Aqueous suspension and preparation method thereof

An aqueous suspension of a multivalent-metal-modified salicylic acid resin, which is suitable for use in the production of color-developing sheets for pressure-sensitive recording paper sheets, contains a specific multivalent-metal-modified salicylic acid resin at the first-mentioned resin. Fine particles of the specific multivalent-metal-modified salicylic acid is dispersed in an aqueous solution of a dispersant composed of at least one compound selected from the group consisting of: PA0 (a) water-soluble anionic high-molecular compounds composed of polyvinyl alcohol derivatives containing sulfonic acid groups in their molecules, and salts thereof, PA0 (b) acrylamide-modified polyvinyl alcohols, and PA0 (c) water-soluble anionic high-molecular compounds composed of polymers or copolymers comprising particular styrenesulfonic acid derivatives as their essential components. The aqueous dispersion is prepared by finely grinding the specific multivalent-metal-modified salicylic acid in the aqueous solution of the dispersant.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an aqueous suspension suitable for use as a 
color-developing agent, more specifically, to an aqueous suspension of a 
multivalent-metal-modified salicylic acid resin having a novel composition 
and disclosed in any one of the present assignee's or applicant's 
preceding patent applications to be referred to subsequently, and notably, 
to an aqueous suspension of a novel oil-soluble multivalent-metal-modified 
salicylic acid resin, which is useful as a material for pressure-sensitive 
copying papers. This invention is also concerned with a method for the 
preparation of the above-mentioned aqueous suspension. 
2. Description of the Related Art 
A pressure-sensitive copying paper is generally composed of a sheet 
(CB-sheet) coated with microcapsules of a non-volatile organic solvent 
containing an electron-donating organic compound (so-called 
pressure-sensitive dyestuff) and another sheet (CF-sheet) coated with an 
aqueous coating formulation containing an electron-attracting 
color-developing agent. The CB-sheet and CF-sheet are arranged with their 
coated sides maintained in a contiguous relation. The microcapsules are 
ruptured, for example, by a writing or printing impression of a ballpoint 
pen or a typewriter, whereby the solution of the pressure-sensitive 
dyestuff is caused to flow out of the capsules and is then brought into 
contact with the color-developing agent and a color is hence produced. By 
changing the combination of the layer of the microcapsules containing the 
pressure-sensitive dyestuff and the layer of the color-developing agent, 
many copies can be produced and self-contained pressure-sensitive copying 
papers (SC paper sheets) can be produced. 
As a colorless or slightly-colored dyestuff precursor useful in such 
pressure-sensitive copying papers, one or more compounds are selected 
from: 
(1) triarylmethanephthalide compounds such as crystal violet lactone; 
(2) fluorane compounds such as 3-dibutylamino-6-methyl-7-anilinofluorane; 
(3) pyridylphthalide compounds; 
(4) phenothiazine compounds; and 
(5) leucoauramine compounds. 
Said one or more compounds are dissolved in a hydrophobic phobic high 
boiling-point solvent and microencapsulated for their application. 
As electron-attracting color-developing agents on the other hand, there 
have conventionally been used (1) inorganic solid acids such as acid clay 
and activated clay, (2) oil-soluble phenol-formaldehyde condensation 
products and their multivalent-metal-modified products and (3) multivalent 
metal salts of substituted salicylic acids by way of example. These 
color-developing agents cannot however provide marks having sufficient 
stability, so that produced color marks may be discolored or faded during 
their storage or their water resistance or solvent resistance may be 
insufficient. 
As color-developing agents free of such problems, the present inventors 
have already found novel multivalent-metal-modified salicylic acids on 
which patent applications have been made [Japanese Patent Application No. 
262019/1986 and others, which are the priority applications for U.S. 
patent application Ser. No. 111,763, filed on Oct. 23, 1987, and Japanese 
Patent Application No. 87030/1987]. 
In order to produce pressure-sensitive copying papers by using a 
color-developing agent, the color-developing agent is generally wet-ground 
in the presence of a surfactant into an aqueous suspension of fine 
particles having a particle size of 1-10 .mu.m. A dispersant is used for 
this purpose. 
The selection of the combination of particles to be dispersed and a 
dispersant for obtaining a good dispersion system is however based 
primarily on experiences, and there is no general rule for the selection. 
Upon selection of a dispersant, it is necessary to take into consideration 
not only dispersing effects but also influence and the like to the action 
of particles to be dispersed. 
For these reasons, it is not easy to combine one of the 
multivalent-metal-modified salicylic acid resins with its matching 
dispersant to prepare an aqueous suspension having good properties in 
various aspects such as the state of dispersion, stability, 
color-developing ability, etc. Anionic high-molecular surfactants of the 
polycarboxylic acid type, specifically, the sodium salts of maleic 
anhydridediisobutyrene copolymers are generally employed as dispersants 
for p-phenylphenol-formaldehyde and p-octylphenol-formaldehyde polymers 
which are currently used as color-developing agents for pressure-sensitive 
recording paper sheets. When each of these surfactants is used as a 
dispersant for the conversion of any one of the multivalent-metal-modified 
salicylic acid resins into an aqueous suspension, the formation of an 
inconvenient complex salt takes place between the multivalent metal and 
the carboxylic acid salt. Hence, the dispersing effects and dispersion 
stability are reduced, hardly defoamable foams are formed, and the 
physical properties of the color-developing agent are changed due to 
modification of the multivalent-metal-modified salicylic acid resin as a 
dispersed substance. It is by no means possible to obtain any suspension 
which may be used practically. 
Although some of salts of formaldehyde condensation products of 
naphthalenesulfonic acid, salts of ligninsulfonic acid and like salts, 
which were used previously for color-developing agents of the 
phenol-formaldehyde condensation products, have dispersing effects for the 
multivalent-metal-modified salicylic acid resins, they substantially lack 
practical utility because paper surfaces are colored or undergo 
light-yellowing due to the inclusion of the dispersant when employed in 
pressure-sensitive copying papers. 
SUMMARY OF THE INVENTION 
With a view toward solving the above-described problems, a principal object 
of this invention is to provide an aqueous suspension which is good in the 
state of dispersion, stability and the like and is usable very 
conveniently upon production of pressure-sensitive copying papers. Another 
principal object of this invention is to provide an aqueous suspension 
which permits the production of high-quality pressure-sensitive copying 
papers having high mark stability, water resistance and solvent resistance 
so that the sheet surfaces remain free from coloration, yellowing and the 
like and color marks produced thereon are not discolored or faded during 
their storage. 
In one aspect of this invention, there is thus provided an aqueous 
suspension of a multivalent-metal-modified salicylic acid resin. The 
multivalent-metal-modified salicylic acid resin is selected from the group 
consisting of: 
(A) first multivalent-metal-modified products of a salicylic acid resin 
comprising structural units represented by the following formulae (I) and 
(II): 
##STR1## 
wherein R.sub.1 and R.sub.2 are independently a hydrogen atom or a 
C.sub.1-12 alkyl, aralkyl, aryl or cycloalkyl group and R.sub.3 denotes a 
hydrogen atom or a C.sub.1-4 alkyl group, said structural units (I) and 
(II) accounting for 5-40 mole % and 60-95 mole % respectively, each of 
said structural units (I) being coupled with one of said structural units 
(II) via the .alpha.-carbon atom of said one of said structural units 
(II), one or more of said structural units (II) being optionally coupled 
via the .alpha.-carbon atom or .alpha.-carbon atoms thereof with the 
benzene ring or rings of another or other structural units (II), and said 
salicylic acid resin having a weight average molecular weight of 
500-10,000, 
(B) second multivalent-metal-modified products of another salicylic acid 
resin comprising structural units represented by the following formulae 
(I), (II) and (III): 
##STR2## 
wherein R.sub.1 and R.sub.2 are independently a hydrogen atom or a 
C.sub.1-12 alkyl, aralkyl, aryl or cycloalkyl group, R.sub.3 and R.sub.6 
denote independently a hydrogen atom or a C.sub.1-4 alkyl group and 
R.sub.4 and R.sub.5 are individually a hydrogen atom or a methyl group, 
said structural units (I), (II) and (III) accounting for 5-35 mole %, 
10-85 mole % and 4-85 mole % respectively, each of said structural units 
(I) being coupled with one of said structural units (II) via the 
.alpha.-carbon atom of said one of said structural units (II), one or more 
of said structural units (II) being optionally coupled via the 
.alpha.-carbon atom or .alpha.-carbon atoms thereof with the benzene ring 
or rings of another or other structural units (II), each of said 
structural units (III) being coupled via the .alpha.-carbon thereof with 
the benzene ring of one of the structural units (II) and/or (III), and 
said another salicyclic acid resin having a weight average molecular 
weight of 500-10,000, and 
(c) third multivalent-metal-modified products of a further salicyclic acid 
resin comprising structural units represented by the following formulae 
(IV) and (V): 
##STR3## 
wherein R.sub.1, R.sub.2, R.sub.7, R.sub.8, R.sub.9 and R.sub.9 ' are 
independently a hydrogen atom or a C.sub.1-12 alkyl, aralkyl, aryl or 
cycloalkyl group, R.sub.7 and R.sub.8 may optionally be bonded to adjacent 
carbons of the corresponding benzene ring and form a ring together with 
the adjacent carbons, and X and X' denote independently a direct bond or a 
straight-chain or branched divalent C.sub.1-5 hydrocarbon group, said 
structural units (IV) and (V) accounting for 10-70 mole % and 30-90 mole % 
respectively, each of said structural units (V) being coupled with one of 
said structural units (IV) and/or (V) via the .alpha.-carbon atom of said 
one of said structural units (V), and said further salicylic acid resin 
having a weight average molecular weight of 500-10,000; and 
the multivalent-metal-modified salicylic acid resin is dispersed as fine 
particles in an aqueous solution of a dispersant composed of at least one 
compound selected from the group consisting of: 
(a) water-soluble anionic high-molecular compounds composed of polyvinyl 
alcohol derivatives containing sulfonic acid groups in their molecules, 
and salts thereof, 
(b) acrylamide-modified polyvinyl alcohols, and 
(c) water-soluble anionic high-molecular compounds composed of polymers or 
copolymers comprising as their essential components styrenesulfonic acid 
derivatives represented by the following general formula (VI): 
##STR4## 
wherein R is a hydrogen atom or a C.sub.1-5 alkyl group and M denotes 
Na.sup.+, K.sup.+, Li.sup.+, Cs.sup.+, Rb.sup.+, Fr.sup.+ or 
NH.sub.4.sup.+. 
In another aspect of this invention, there is also provided a method for 
the preparation of the above-described aqueous suspension. The 
multivalent-metal-modified salicylic acid resin selected from the group 
consisting of the products (A), (B) and (C) is finely ground in the 
aqueous solution of the dispersant composed of at least one compound 
selected from the group consisting of the compounds (a) and (c) and the 
acrylamide-modified polyvinyl alcohols (b). 
The particle size of the multivalent-metal-modified salicylic acid resin in 
the aqueous suspension of the present invention may be 0.5-1.0 .mu.m. The 
solid content of the aqueous suspension may be 10-70 wt. %, preferably, 
30-60 wt. %. The compound used as the dispersant may be contained in an 
amount of 0.3-30 parts by weight, preferably, 2-20 parts by weight per 100 
parts by weight of the multivalent-metal-modified salicylic acid resin. 
A color-developing sheet making use of the aqueous suspension of this 
invention has either equal or better color-producing property compared 
with color-developing sheets obtained by using an inorganic solid acid or 
p-phenylphenol novolak resin, is better in low-temperature color-producing 
property compared with color-developing sheets obtained by using a metal 
salt of an aromatic carboxylic acid, and can produce color marks having 
high fastness so that they are not readily faded out by water, 
plasticizers or light. 
The yellowing problem which takes place upon exposure to sunlight has also 
been improved. In particular, the yellowing by NO.sub.x in air has been 
improved significantly. The aqueous suspension of this invention therefore 
has a merit that it can economically provide color-developing sheets 
extremely advantageous for handling and storage. 
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS 
The multivalent-metal-modified salicylic acid resin products (A) and (B) 
[hereinafter abbreviated merely as "resin (A)" and "resin (B)"] useful in 
the practice of this invention will be described. The resins (A) and (B) 
have already been described in detail in the specification of Japanese 
Patent Application No. 262019/1986 and others (corresponding to U.S. 
patent application Ser. No. 111,763) referred to above, regarding their 
preparation processes, their performances when employed as 
color-developing agents, etc. 
The resin (A) may be prepared, for example, by condensing, in the presence 
of an acid catalyst, salicyclic acid with a benzyl alcohol or benzyl ether 
represented by the following general formula (VIII): 
##STR5## 
wherein R.sub.1, R.sub.2 and R.sub.3 are the same as defined above in the 
general formula (II) and R.sub.10 denotes a hydrogen atom, C.sub.1-4 alkyl 
group or 
##STR6## 
or a mixture thereof or with a benzyl halide represented by the following 
general formula (IX): 
##STR7## 
wherein R.sub.1, R.sub.2 and R.sub.3 are the same as defined above in the 
general formula (II) and X denotes a halogen atom, and then converting the 
resultant salicyclic acid resin into the multivalent-metal-modified 
product. 
The resin (B) may be prepared, for example, by condensing a resin, which 
has been obtained likewise the synthesis of the salicylic acid resin of 
the resin (A) before its conversion to the multivalent-metal-modified 
product, with a styrene derivative represented by the following general 
formula (X): 
##STR8## 
wherein R.sub.4, R.sub.5 and R.sub.6 are the same as defined above in the 
general formula (III), in the presence of an acid catalyst, and then 
converting the resultant salicylic acid resin into the 
multivalent-metal-modified product. 
As specific examples of the salicylic acid resin in the resin (B), may be 
mentioned salicylic acid-p-methyl-.alpha.-benzylalcohol-styrene resins, 
salicylic acid-benzyl methyl ether-styrene resins, salicylic acid-benzyl 
alcohol-a-methylstyrene resins, salicylic acid-benzyl alcohol-styrene 
resins, salicylic acid-p-methylbenzyl methyl ether-styrene resins, 
salicylic acid-.alpha.-methylbenzyl alcohol-styrene resins, salicylic 
acid-.alpha.-methylbenzyl ethyl ether-.alpha.-methylstyrene resins, etc. 
The term "multivalent-metal-modified product of salicylic acid resin" or 
"multivalent-metal-modified salicylic acid resin" means either a salt 
formed between multivalent metal ions and intramolecular or intermolecular 
carboxyl groups of the salicylic acid resin or a molten mixture containing 
the multivalent metal salt. 
Several known processes may be applied for the preparation of the 
multivalent metal salt from the salicylic acid resin. For example, it may 
be prepared by reacting an alkali metal salt of the resin with a 
water-soluble multivalent metal salt in water or a solvent in which the 
alkali metal salt and multivalent metal salt are both soluble. Namely, it 
may be prepared by reacting the salicylic acid resin with the hydroxide or 
carbonate of an alkali metal, an alkoxide of an alkali metal, or the like 
to obtain the alkali metal salt of the salicylic acid resin or a solution 
of the alkali metal salt in water, an alcohol or a mixed water-alcohol 
solvent, followed by a further reaction with the water-soluble multivalent 
metal salt. 
The multivalent-metal-modified product may also be obtained by neutralizing 
the resin without its separation after the condensation and hence reacting 
the resin with a multivalent metal salt employed as a Friedel-Crafts 
catalyst. 
The molten mixture containing the multivalent metal salt of the salicylic 
acid resin may be produced by mixing the salicylic acid resin with a 
multivalent metal salt of an organic carboxylic acid such as formic acid, 
acetic acid, propionic acid, valeric acid, capric acid, stearic acid or 
benzoic acid, reacting them under heat in a molten state, and then cooling 
the resultant reaction mixture. In some instances, a basic substance, for 
example, ammonium carbonate, ammonium bicarbonate, ammonium acetate or 
ammonium benzoate may be added, followed by a further reaction under heat 
in a molten state. 
As an alternative, the molten mixture may also be prepared by using 
salicylic acid and the carbonate, oxide or hydroxide of a multivalent 
metal, heating, melting and reacting them with a basic substance, e.g., 
the ammonium salt of an organic carboxylic acid, such as ammonium formate, 
ammonium acetate, ammonium caproate, ammonium stearate or ammonium 
benzoate, and then cooling the reaction mixture. 
As preferred multivalent metals, may be mentioned calcium, magnesium, 
aluminum, copper, zinc, tin, barium, cobalt, nickel, etc. Among these, 
zinc is particularly preferred. 
Of multivalent-metal-modified salicylic acid resins obtained in the 
above-described manner, are generally employed those having a softening 
point of 50.degree. C. -120.degree. C. as measured in accordance with the 
ring and ball softening-point measuring method prescribed in JIS K-2548 
(softening points to be referred to hereinafter will all mean those 
determined by this method). 
The multivalent-metal-modified salicyclic acid resin product (C) 
[hereinafter abbreviated merely as "resin (C)"] useful in the practice of 
this invention will next be described. 
As already mentioned above, the present applicant or assignee has disclosed 
its composition, its preparation process, its performance as a 
color-developing agent, etc. in Japanese Patent Application No. 
87030/1987. The preparation process may be outlined as follows. A 
salicyclic acid derivative represented by the following general formula 
(XI): 
##STR9## 
wherein R.sub.7, R.sub.8, R.sub.9, R.sub.9 ', X and X' are the same as 
defined above in the general formula (IV) and n stands for 1 or 0 is 
reacted in the presence of a Friedel-Crafts catalyst with a benzyl halide 
represented by the following general formula (XII): 
##STR10## 
wherein R.sub.1 and R.sub.2 are the same as defined above in the general 
formula (V) and X is a halogen atom. The resulting resin composition is 
then converted into its multivalent-metal-modified product in the same 
manner as that described in the preparation processes of the resins (A) 
and (B). Preferred multivalent metals and the softening point of the 
multivalent-metal-modified product are the same as those described in 
connection with the resins (A) and (B). 
At least one of the following compounds is also used in the practice of 
this invention. 
(a) Water-soluble anionic high-molecular compounds composed of polyvinyl 
alcohol derivatives containing sulfonic acid groups in their molecules or 
salts thereof, 
(b) Acrylamide-modified polyvinyl alcohols, and 
(c) Water-soluble anionic high-molecular compounds composed of polymers or 
copolymers comprising as their essential components styrenesulfonic acid 
derivatives represented by the following general formula (VI): 
##STR11## 
wherein R is a hydrogen atom or a C.sub.1-5 alkyl group and and M denotes 
Na.sup.+, K.sup.+, Li.sup.+, Cs.sup.+, Rb.sup.+, Fr.sup.+ or 
NH.sub.4.sup.+. 
The compounds (a), (b) and (c) act individually as a dispersant for the 
resin (A), (B) or (C) in the suspension of this invention. These compounds 
will hereinafter be abbreviated as "dispersants (a)" "dispersants (b)" and 
"dispersants (c)" respectively and described in detail. 
(i) Dispersants (a) 
The dispersants (a) may each be prepared, for example, by any one of the 
following processes: 
(1) Vinyl acetate is copolymerized with an .alpha., .beta.-unsaturated 
monomer containing at least one sulfonic acid group in its molecule, 
followed by saponification. 
(2) Polyvinyl alcohol is reacted with concentrated sulfuric acid. 
(3) Polyvinyl alcohol is oxidized with bromine, iodine or the like, 
followed by a reaction with acidic sodium sulfite. 
(4) An aldehyde compound containing one or more sulfonic acid groups is 
reacted with polyvinyl alcohol in the presence of an acid catalyst, 
whereby polyvinyl alcohol is converted into a sulfoacetal. 
Among dispersants (a) obtained by the above processes, it is preferable to 
use those obtained by saponifying copolymers of vinyl acetate and 
.alpha.,.beta.-unsaturated monomers containing one or more sulfonic acid 
groups. 
As specific examples of .alpha., .beta.-unsaturated monomers containing one 
or more sulfonic groups, may be mentioned: 
(a) sulfoalkyl acrylates, for example, sulfoethyl acrylate and sulfoethyl 
methacrylate; 
(b) vinylsulfonic acid, styrenesulfonic acid and allylsulfonic acid; 
(c) Maleinimide-N-alkanesulfonic acids; and 
(d) 2-acrylamido-2-methylpropanesulfonic acid and 
2-acrylamido-2-phenylpropanesulfonic acid. 
The dispersants (a) may each be obtained by copolymerizing such an .alpha., 
.beta.-unsaturated monomer in a proportion of 0.5-20 moles, preferably, 
1-10 moles per 100 moles of vinyl acetate and then saponifying (50-100%) 
the vinyl acetate moieties under alkaline conditions by a method known per 
se in the art. 
As an alternative, they may also be obtained individually by sulfonating a 
copolymer of vinyl acetate and an aromatic .alpha., .beta.-unsaturated 
monomer such as styrene and then saponifying the thus-sulfonated 
copolymer. The dispersants (a) also include high molecular compounds 
obtained individually by copolymerizing vinyl acetate with an .alpha., 
.beta.-unsaturated monomer containing at least one sulfonic acid group in 
its molecule and another .alpha., .beta.-unsaturated monomer. 
In this invention, the sulfonic acid groups in the molecule of dispersant 
(a) are generally employed in such a form that their sulfonic acid groups 
have been converted into the alkali metal (Na.sup.+, K.sup.+, Li.sup.+, 
Cs.sup.+, Rb.sup.+ or Fr.sup.+) or NH.sub.4.sup.+ salts. 
Unlike conventional completely- or partly-saponified polyvinyl alcohols, 
each of the dispersants (a) has high solubility in water and is hence 
dissolved easily in water, shows less viscosity variations over a wide pH 
range, is substantially colorless or colored in an extremely pale color 
and thus does not color an aqueous suspension of a 
multivalent-metal-modified salicyclic acid resin to be obtained by using 
the same, and accordingly does not color pressure-sensitive copying paper 
sheets (CF-sheets) to be produced by using the aqueous suspension. With 
the own characteristics of the dispersants (a) that they are neither 
modified nor discolored under severe environmental conditions, they have 
excellent dispersing effects for the multivalent-metal-modified salicyclic 
acid resins useful in the practice of this invention. They can therefore 
provide aqueous suspensions of the multivalent-metal-modified salicylic 
acid resins, which suspensions are stable thermally, mechanically and 
chemically. 
Different from completely-saponified polyvinyl alcohols, partly-saponified 
polyvinyl alcohols and carboxyl-modified polyvinyl alcohols which are 
employed generally, the dispersants (a) have lower foaming tendency and 
are superb in self-defoaming property. The dispersants (a) can therefore 
eliminate troubles which would otherwise arise due to foams in the course 
of a dispersing operation. 
The dispersants (a) are equipped with both anionic and nonionic properties 
and have not only excellent dispersing effects but also protective 
colloidal effects. Dispersions obtained by using the dispersants (a) are 
far superior in mechanical stability and thermal stability to dispersions 
making use of other anionic surfactants. 
The polyvinyl alcohols which have sulfonic acid groups in their molecules 
and are useful in the present invention are generally available as either 
white or light-colored powders soluble readily in water or as aqueous 
solutions. Upon production of aqueous suspensions, they are beforehand 
dissolved separately in water and then adjusted to a pH range of 4-10, 
preferably, 6-9 prior to their use. 
(ii) Dispersants (b) 
Each of the dispersants (b) may generally be obtained by copolymerizing 
vinyl acetate and acrylamide and then saponifying the resultant copolymer. 
It is therefore possible to obtain those having varied average molecular 
weights and acrylamide contents. 
The dispersants (b) useful in the practice of this invention have an 
average polymerization degree of 200-2000, preferably, 500-1500 and an 
acrylamide content of 2-30 mole %, preferably, 3-15 mole %. 
Since the dispersants (b) usable in the present invention themselves are 
substantially colorless or extremely light-colored, they do not color the 
resultant aqueous suspensions of multivalent-metal-modified salicylic acid 
resins. Accordingly, they do not color pressure-sensitive copying papers 
to be produced by using the aqueous suspensions separately. With their own 
characteristics that they are neither modified nor discolored under severe 
environmental conditions, they have excellent dispersing effects for the 
resin (A), (B) or (C) and provide aqueous suspensions of the 
multivalent-metal-modified salicylic acid resins, which suspensions are 
stable thermally, mechanically and chemically. 
Different from conventional completely- or partly-saponified polyvinyl 
alcohols and carboxyl-modified polyvinyl alcohols, the dispersants (b) 
have lower foaming tendency and are superb in self-defoaming property. The 
dispersants (b) can therefore eliminate troubles which would otherwise 
arise due to foams in the course of a dispersing operation. 
Each of the dispersants (b) also has a function as a binder for binding an 
aqueous formulation, which has been obtained by mixing the aqueous 
suspension of this invention with an inorganic pigment or the like, to 
paper. 
In this invention, one or more of other anionic and/or nonionic 
surfactants, one or more high-molecular surfactants or one or more 
water-soluble high molecular compounds having protective colloidal effects 
may also be used in combination in order to control the viscosity and 
rheological characteristics of the aqueous suspension to be obtained. 
The dispersants (b) are generally available as either white or 
light-colored powders soluble readily in water or as aqueous solutions. 
Upon production of aqueous suspensions, they are beforehand dissolved 
separately in water and then adjusted to a pH range of 4-10, preferably, 
6-9 prior to their use. 
(iii) Dispersants (c) 
The water-soluble anionic high-molecular compounds useful as the 
dispersants (c) in this invention include a group of substances known as 
agents for imparting electrical conductivity to electrophotographic paper 
sheets and electrostatic recording paper sheets. However, it has not been 
known at all that they exhibit superb properties when employed as 
dispersants, especially, for forming multivalent-metal-modified salicylic 
acid resins into aqueous suspensions according to this invention. 
As suitable specific examples, may be mentioned salts of 
polystyrenesulfonic acid derivatives represented by the following general 
formula (VII): 
##STR12## 
wherein R is a hydrogen atom or a C.sub.1-5 alkyl group, M denotes 
Na.sup.+, K.sup.+, Li.sup.+, Cs.sup.+, Rb.sup.+, Fr.sup.+ or 
NH.sub.4.sup.+, n stands for an integer of 5-10,000, m is an integer 
ranging from 1 to 10,000 but not exceeding n, and one or more of the Rs in 
each molecule may be different from the rest of the Rs. Preparation 
processes of such inorganic salts of polystyrenesulfonic acid derivatives 
may include the sulfonation of polystyrene and polymerization of 
styrenesulfonic acid (or a salt thereof). 
Besides, salts of copolymers of styrenesulfonic acid and maleic anhydride, 
salts of sulfonation products of styrene-maleic acid copolymers, salts of 
copolymers of styrenesulfonic acid and other vinyl compounds, salts of 
sulfonated products of copolymers of styrene and other vinyl monomers, 
etc. may be used. Two or more of these salts may also be used in 
combination. 
The dispersants (c) useful in the present invention are stable over a wide 
pH range and have an extremely light color. They hence do not color 
aqueous suspensions of the resin (A), (B) or (C), which are to be obtained 
by using them. Accordingly, they do not color pressure-sensitive copying 
papers (CF-sheets) which are to be produced by using the aqueous 
suspensions separately. With the characteristics of the dispersants (c) 
that they are neither modified nor discolored under severe environmental 
conditions, they have excellent dispersing effects for the resin (A), (B) 
or (C). Among these dispersants, the inorganic salts of 
polystyrenesulfonic acid derivatives represented by the general formula 
(VII) can be employed preferably because they can provide particularly 
good aqueous suspensions of the resin (A), (B) or (C) and they are readily 
available. 
In the present invention, the resin (A), (B) or (C) having excellent 
properties can be converted into an aqueous suspension having a high solid 
content, a low viscosity and superb dispersion stability by finely 
wet-grinding the resin in an aqueous solution which uses as a dispersant a 
water-soluble anionic high-molecular substance comprising a polymer or 
copolymer composed as an essential component of a styrenesulfonic acid 
derivative represented by the general formula (VI). 
Further, one or more of other anionic and/or nonionic surfactants or one or 
more water-soluble high molecular compounds having protective colloidal 
effects may also be used in combination in order to control the viscosity 
and rheological characteristics of the aqueous suspension. 
Such dispersants(c) are generally available as either white or 
light-colored powders soluble readily in water or as aqueous solutions. 
Upon production of aqueous suspensions, they are beforehand dissolved 
separately in water and then adjusted to a pH range of 4-10, preferably, 
6-9 prior to their use. 
In order to produce an aqueous suspension of the resin (A), (B) or (C) by 
using the dispersant (a), (b) and/or (c) (hereinafter simply referred to 
as "dispersant"), the resin (A), (B) or (C) is charged to a concentration 
of 10-70 wt. %, preferably, 30-60 wt. % into a solution which has been 
formed by dissolving the dispersant in water and then adjusting the pH of 
the resultant solution to 4-10, preferably, 6-9. The resultant mixture is 
stirred into a slurry and is then finely wet-ground to an average particle 
size of 0.5-10 .mu.m by means of a wet-grinding apparatus, for example, an 
apparatus designed to perform wet-grinding by means of a spherical 
grinding medium, such as a ball mill, attritor or sand grinder, whereby an 
aqueous suspension is formed. Such fine wet-grinding may be performed 
batchwise or continuously. The fine wet-grinding is continued until a 
desired particle size is achieved. 
Where the softening point of the resin (A), (B) or (C) is so low that it is 
liquefied easily at a temperature not higher than the boiling point of 
water, an aqueous suspension can be obtained by stirring the 
multivalent-metal-modified salicylic acid resin at a high speed in warm or 
hot water to emulsify the resin in water and then cooling the emulsion 
thus formed. 
One or more of other anionic and/or nonionic surfactants or one or more 
water-soluble high molecular compounds having protective colloidal effects 
may also be used in combination in order to control the viscosity and 
rheological characteristics of the aqueous suspension. 
The amount of the dispersant to be used varies depending on the kind and 
physical properties of the material [the resins (A), (B) or (C)] to be 
dispersed and the physical properties (solid concentration, the viscosity 
of the material dispersed, etc.) of the intended aqueous suspension, and 
no particular limitation is imposed thereon. In order to obtain a 
practical aqueous suspension (solid content: 30-60 wt. %, average particle 
size: 0.5-10 .mu.m), the dispersant may be used in an amount of 0.3-30 
parts by weight, preferably, 2-20 parts by weight per 100 parts by weight 
of the resin (A), (B) or (C). 
Further, the average particle size of the multivalent-metal-modified 
salicylic acid resin in the aqueous suspension may be 10 .mu.m or smaller, 
preferably, in a range of 0.5-5 .mu.m. If particles greater than 10 .mu.m 
are contained in a large proportion, more sediment occurs while the 
aqueous suspension is stored standstill. In addition, the color-producing 
performance, especially, the concentration of a color immediately after 
its production is reduced. If the particle size is smaller than 0.5 .mu.m, 
the aqueous suspension shows a thickening behavior. It is hence difficult 
to form a thick aqueous suspension and also to handle the resultant 
aqueous suspension. 
The dispersants useful in the practice of this invention do not exhibit 
thickening tendency (shock) when mixed with a dispersion of another 
component, for example, a white inorganic pigment such as kaolin or 
calcium carbonate upon preparation of a coating formulation suitable for 
use in the production of pressure-sensitive copying papers. 
The aqueous suspension obtained in the above manner, which pertains to the 
present invention and contains the multivalent-metal-modified salicylic 
acid resin, can have a higher solid content and a lower viscosity. The 
aqueous suspension can therefore provide an aqueous coating formulation of 
a higher solid content for the production of pressure-sensitive copying 
paper. The aqueous coating formulation can therefore be applied especially 
by a coating machine of the type that the coating is performed by using an 
aqueous coating formulation of a high solid content, such as blade coater 
or roll coater. 
Pressure-sensitive copying papers produced from the aqueous coating 
formulation making use of the aqueous suspension of the present invention 
enjoy improved color-producing performance and owing to the low thickening 
tendency of the aqueous coating formulation, substantial effects have also 
been brought about for the improvement of the efficiency of coating work. 
The air-knife coating method making use of a low-viscosity coating 
formulation is convenient, since foaming is significantly suppressed upon 
recirculation of the aqueous coating formulation. 
Although the dispersants (a), (b) and (c) individually show excellent 
performance as has been described above, they may also be used in 
combination. The combined use generally makes it possible to reduce the 
amount of a dispersant to be used upon formation of an aqueous suspension. 
It is hence possible to obtain an aqueous suspension of a 
multivalent-metal-modified salicylic acid resin, which is more stable 
compared with those available by using the dispersants singly. 
When the dispersants (a) and (b) are used in combination, an 
extremely-stable aqueous suspension can be obtained by using them in a 
total amount of 10 parts by weight or less per 100 parts by weight of each 
resin. 
Upon production of pressure-sensitive copying papers by using the aqueous 
suspension of this invention, in order to adjust the characteristics of 
the surfaces of the pressure-sensitive copying papers to be obtained, (1) 
an inorganic or organic pigment, (2) a pigment dispersant, (3) a coating 
binder and (4) various additives are mixed first of all to prepare an 
aqueous coating formulation suitable for a coating method to be employed. 
A base paper web is thereafter coated with a coating formulation, followed 
by drying into the pressure-sensitive copying papers. 
As the inorganic or organic pigment (1) employed here, may be mentioned 
kaolin, calcined kaolin, bentonite, talc, calcium carbonate, barium 
sulfate, aluminum oxide (alumina), silicon oxide (silica), satinwhite, 
titanium oxide, polystyrene emulsion or the like. Illustrative examples of 
the pigment dispersant (2) useful here may include phosphates such as 
sodium methaphosphate, sodium hexamethaphosphate and sodium 
tripholyphosphate as well as polycaroxylates such as sodium polyacrylate. 
As exemplary coating binders (3), may be used denatured starches such 
oxidized starch, enzyme-converted starch, starch urea phosphate and 
alkylated starch, water-soluble proteins such as casein and gelatin, and 
synthetic and semi-synthetic binders such as styrene-butadiene latex 
(SBR), methyl methacrylate-butadiene latex (MBR), emulsions of vinyl 
acetate polymers, polyvinyl alcohol, carboxymethylcellulose, 
hydroxyethylcellulose and methylcellulose. As various other additives, 
fluorescent brightening agents, defoaming agents, viscosity modifiers, 
anti-dusting agents, lubricants, waterproofing agents, etc. may be 
employed. 
By an air-knife coater, blade coater, brush coater, roll coater, bar 
coater, gravure coater or the like, a base paper web is coated with the 
aqueous coating formulation prepared by mixing the aqueous suspension of 
this invention and the above-mentioned various components and dispersing 
the latter in the former. The thus-coated paper web is then dried to form 
color-developing sheets for pressure-sensitive copying papers. 
The aqueous coating formulation may generally be coated to give a dry coat 
weight of at least 0.5 g/m.sup.2, preferably, 1-10 g/m.sup.2. The 
color-producing properties of a sheet coated with the aqueous coating 
formulation are governed primarily by the concentration of the 
multivalent-metal-modified salicylic acid resin contained in the aqueous 
coating formulation. Dry coat weights greater than 10 g/m.sup.2 are not 
effective for the improvement of the color-producing properties and are 
disadvantageous from the economical standpoint. 
The superiority of the aqueous suspension of this invention for the 
production of pressure-sensitive paper sheets is appreciated from the 
following advantageous effects. For example, the aqueous suspension of 
this invention has little thickening tendency and the efficiency of 
coating work of an aqueous coating formulation formed principally of the 
aqueous suspension has been improved considerably. The use of the 
air-knife coating method, which uses a low-viscosity coating formulation 
at the time of coating work, is convenient for coating the aqueous coating 
formulation making use of the aqueous suspension of this invention, since 
the foaming is suppressed significantly upon recirculation of the aqueous 
coating formulation. The aqueous suspension of this invention does not 
exhibit thickening tendency (shock) when it is mixed with other common 
components, for example, a white inorganic pigment such as kaolin clay or 
calcium carbonate upon preparation of an aqueous coating formulation 
suitable for use in the production of pressure-sensitive copying papers. 
In addition, the aqueous suspension has a high solid content and is 
excellent in thermal stability. An aqueous coating formulation making use 
of the aqueous suspension is hence superb in both thermal and mechanical 
stability and can be employed suitably for a coating machine which 
performs coating work by using an aqueous coating formulation of a high 
solid content, especially, for a blade coater or roll coater. 
Novel color-developing sheets, which have been produced by using the 
aqueous suspension of this invention and are suited for use in 
pressure-sensitive copying papers, have various advantages. For example, 
they have either equal or better color-producing ability compared with 
color-developing sheets making use of an inorganic solid acid or 
p-phenylphenol novolak resin. The yellowing resistance upon exposure to 
sunlight has also been improved substantially, so that they are extremely 
advantageous in handling and storage.

EXAMPLES 
The present invention will hereinafter be described in detail by the 
following Examples and Comparative Examples. 
Properties of aqueous suspensions, aqueous coating formulations and 
pressure-sensitive copying papers obtained in the following Examples and 
Comparative Examples will be summarized in Tables 1-3. 
The following testing methods were employed for the determination of the 
respective properties. 
(A) Properties of aqueous suspensions 
(I) Hue 
A wood free paper web was coated with each aqueous suspension by using 
Meyer bar to give a dry coat weight of 5 g/m.sup.2. Four sheets cut off 
from the thus-coated paper web (i.e., sheets coated with the aqueous 
suspension) were superposed one over another and the reflectivity was 
measured by a Hunter colorimeter, Model TSS (manufactured by Toyo Seiki 
Seisakusho, Ltd.) through a blue filter. The whiteness of the sheets 
coated with the aqueous suspension will be expressed in terms of 
reflectivity (A). 
Higher reflectivity (A) indicates that the corresponding aqueous suspension 
has greater whiteness. The superiority or inferiority between two aqueous 
suspensions can be distinguished visually so long as their difference in 
reflectivity is about 1% or greater. 
(II) Viscosity 
After adjusting the solid content of each aqueous suspension to 40 wt. %, 
its viscosity was measured at 60 rpm by a Brookfield viscometer equipped 
with a No. 1 rotor. The viscosity is expressed by a figure thus measured 
in centipoises. 
(III) High-temperature storage stability 
Two killograms of each aqueous suspension were placed in a stainless beaker 
having an internal capacity of 3 l. The aqueous suspension was stored 
there at 40.degree. C. for 1 week while stirring it at 100 rpm by a 
glass-made stirring blade (anchor type; diameter: 100 mm). Its 
filterability before the storage and that after the storage were compared 
in terms of the filtration time (sec) through a 200 mesh sieve whose 
diameter was 7.5 cm. In a dispersion having poor high-temperature storage 
stability, the particles of the multivalent-metal-modified salicylic acid 
resin coagulated together so that as the particle size grew further, the 
filtration time became longer and the filterability was reduced. 
(B) Properties of aqueous coating formulations 
Using the aqueous suspensions of the Examples and Comparative Examples 
separately, were prepared aqueous coating formulations of the following 
composition (solid content: 50%) suitable for use in the production of 
pressure-sensitive copying papers by the blade coating method. Their 
properties were then measured separately. 
______________________________________ 
Components parts by weight 
______________________________________ 
(1) Aqueous suspension (in terms 
18 
of the multivalent-metal- 
modified salicylic acid resin 
(2) Light calcium carbonate 
100 
(3) Styrene-butadiene latex 
6 
(4) Oxidized starch 6 
(5) Sodium polyacetate 
0.5 
(pigment dispersant) 
______________________________________ 
(I) Viscosity 
The occurrence or non-occurrence of thickening was determined by a 
Brookfield viscometer (No. 3 rotor; 60 rpm). The preferable viscosity is 
in a range of 300-1000 cps. 
(II) Mechanical stability 
Using each of the above-described 50% solid aqueous coating formulations, 
the amount of agglomerates formed was measured by a Marron mechanical 
stability testing machine in accordance with JIS K-6392 (Testing Method 
for NBR Synthetic Latexes) to obtain an index of the mechanical stability 
of the aqueous coating formulation. 
Testing conditions 
100 g sample, 1000 rpm, 10 min, 20 kg load. Subsequent to the test, the 
aqueous coating formulation was caused to pass through a 200 mesh sieve 
for its filtration. The weight of agglomerates was measured after drying 
them in an oven. The amount of the agglomerates is expressed in terms of 
amount (%) of agglomerates formed. 
Aqueous coating formulations indicated a large amount (%) of agglomerates 
formed by the above testing method tend to develop coating troubles due to 
disruption of their dispersion, agglomeration of their solid components, 
etc. when they are applied at a high-speed and subjected to a strong shear 
force, for example, by the blade coating or gate roll coating method. 
(C) Properties as pressure-sensitive copying papers 
Wood free paper webs were coated by a Meyer bar at a rate of dry coat 
weight of 6 g/m.sup.2 respectively with the aqueous coating formulations 
which had been tested by a homomixer with respect to their mechanical and 
thermal stability as described above. The thus-coated paper webs were then 
dried to obtain color-developing sheets for pressure-sensitive copying 
papers of the multiple sheet type. 
(I) Densities of colors produced and color-producing speeds 
In the case of the color-developing sheets for pressure-sensitive copying 
papers of the multiple sheet type, the coated side of color-developing 
sheet was brought into a contiguous relation with the coated side of a 
commercial CB-sheet ("NW-40T", trade name; product of Jujo Paper Co., 
Ltd.) which contained crystal violet lactone (CVL) as a principal 
pressure-sensitive dyestuff. Wood free paper sheets were then placed on 
the top and under the bottom of the thus-combined color-developing sheet 
and CB-sheet. On the other hand, each self-contained pressure-sensitive 
copying paper was sandwiched between wood free paper sheets. Each 
pressure-sensitive copying paper was caused to develop a cobalt blue color 
by an electric typewriter, and its reflectivity was measured by the Hunter 
colorimeter, Model TSS, through an amber filter. The measurement of the 
density of the thus-produced color was conducted on the 1st minute after 
the application of the typewriter impression and also on the 20th hour 
after the color production. The density of the color thus produced is 
expressed in terms of initial color production rate (J.sub.1) and final 
color production rate (J.sub.2): 
##EQU1## 
Where I.sub.O : reflectivity before the color production, 
I.sub.1 : reflectivity on the 1st minute after the color production, and 
I.sub.2 : reflectivity on the 20th hour after the color production. 
The color-producing speed and color density are more preferred as the 
difference between the initial color production rate and the final color 
production rate is smaller and the final color production rate is greater. 
(II) Whiteness of color-developing sheets 
Four color-developing sheets coated and dried in the above-described manner 
were superposed one over another, and the reflectivity was measured by the 
Hunter colorimeter through a blue filter. The whiteness of each 
color-developing sheet is expressed in terms of reflectivity (F). A 
greater F indicates that the color-developing sheet is whiter. The 
difference in whiteness between two color-developing sheets can be 
distinguished visually so long as the difference in reflectivity is about 
0.5% or greater. 
(III) Light yellowing resistance 
Each color-developing sheet, which had not been used for the production of 
a color, was exposed for 10 hours to sunlight. Its reflectivity K.sub.1 
before the exposure and its reflectivity K.sub.2 after the exposure were 
measured by the Hunter colorimeter through a blue filter. The difference 
between K.sub.1 and K.sub.2 indicates the degree of yellowing of the 
color-developing sheet, which can be attributed to the photo-oxidative 
yellowing of the multivalent-metal-modified salicylic acid resin and the 
light yellowing of the dispersant. 
The degree of the light yellowing is expressed by .DELTA.K=K.sub.1 
-K.sub.2. Smaller .DELTA.K indicates less light yellowing of a 
color-developing sheet. 
(IV) Yellowing by NO.sub.x 
Following JIS L-1055 (Testing Method of NO.sub.x - Resistant Color Fastness 
of Dyed Products and Dyes), each color-developing sheet was stored for 1 
hour in a sealed container of an NO.sub.x gas atmosphere formed by the 
reaction between NaNO.sub.2 (sodium nitrite) and H.sub.3 PO.sub.4 
(phosphoric acid). Then the degree of yellowing was investigated. 
The reflectivity was measured by the Hunter colorimeter through a blue 
filter both before and on the 1st hour after its treatment with the 
NO.sub.x gas. 
The smaller the difference between the reflectivity L.sub.1 before the 
treatment and the reflectivity L.sub.2 after the treatment, i.e., 
.DELTA.L=L.sub.1 -L.sub.2, the less the yellowing of a color-developing 
sheet. 
Synthesis Examples of metal-modified salicylic acid resins employed in the 
Examples and Comparative Examples will next be given. 
SYNTHESIS EXAMPLE A-1 
A glass-made reactor was charged with 27.6 g (0.2 mole) of salicylic acid, 
253.2 g (2 moles) of benzyl chloride and as a catalyst, 1.5 g of anhydrous 
zinc chloride They were condensed at 70.degree.-90.degree. C. for 3 hours 
while causing nitrogen gas to flow through the reactor. The temperature 
was thereafter raised to 120.degree. C., at which aging was conducted for 
5 hours to complete the reaction. After pouring 200 ml of toluene and 60 g 
of water under stirring into the reaction mixture, the resultant mixture 
was left over so that the mixture was allowed to separate into layers. The 
weight average molecular weight of a resin thus obtained was 1550. The 
upper solvent layer was charged into a separate glass-made reactor, 
followed by addition of 20 g of 28% aqueous ammonia and 8.1 g (0.1 mole) 
of zinc oxide. The resultant mixture was then stirred for 1 hour at room 
temperature. The mixture was thereafter heated to distill out the solvent. 
The internal temperature was raised to 150.degree. C., at which the 
residue was aged for 2 hours. It was then degasified for 30 minutes in a 
vacuum of 20 mmHg, thereby obtaining 212 g of a zinc-modified salicylic 
acid resin in a clear, reddish brown form (yield: stoichiometric). Its 
softening point was found to be 96.degree. C. It will be designated as 
Resin (A)-1. 
SYNTHESIS EXAMPLE A-2 
A reactor was charged with 27.6 g (0.2 mole) of salicylic acid, 123.7 g 
(0.8 mole) of p-methyl-.alpha.-methylbenzyl chloride, 100 ml of 
monochlorobenzene and as a catalyst, 5.6 g of "Nafion H" (trade name; 
product of E. I. du Pont de Nemours & Co., Inc.). They were reacted for 5 
hours under reflux of the solvent. After the reaction, 300 ml of warm 
water was added and the resultant mixture was stirred for 20 minutes at 
temperatures of 90.degree. C. and higher, and the upper water layer was 
removed. The average molecular weight of a resin thus formed was 850. The 
resin was added with 1500 ml of water, followed by a dropwise addition of 
36 g (0.4 mole) of a 45% aqueous solution of caustic soda. The resultant 
mixture was heated to azeotropically distill out the solvent, whereby an 
aqueous solution was obtained in a somewhat turbid state. The aqueous 
solution was then cooled down to 40.degree. C., to which an aqueous 
solution prepared in advance by dissolving 29 g (0.1 mole) of zinc sulfate 
heptahydrate in 200 ml of water was added dropwise. A white precipitate 
was formed. The precipitate was collected by filtration, washed with water 
and then dried in vacuum, thereby obtaining 126 g of a zinc-modified 
salicylic acid resin. The zinc content was found to be 5.05% by an 
elemental analysis. It will be designated as Resin (A)-2. 
SYNTHESIS EXAMPLE A-3 
Into a reactor, 27.6 g (0.2 mole) of salicylic acid, 74 g (0.4 mole) of 
.alpha.-methylbenzyl bromide and as a catalyst, 15.2 g of zinc chloride 
were charged. They were condensed at 60.degree.-90.degree. C. for 5 hours 
while causing nitrogen gas to flow through the reactor. The temperature 
was thereafter raised to 135.degree. C., at which the reaction was 
continued for 2 hours. 
The weight average molecular weight of a condensation resin thus formed was 
550. 
The reaction product was added with 150 ml of toluene, whereby the reaction 
product was dissolved. Dilute aqueous ammonia was then added dropwise at 
70.degree.-80.degree. C. to adjust the solution to pH 6. The resultant 
solution was added with 8.1 g (0.1 mole) of zinc oxide and then stirred 
for 1 hour at 70.degree.-80.degree. C. to complete the reaction. After 
completion of the reaction, the lower water layer was drawn out. An 
organic layer was concentrated under heat. A molten resin was then taken 
out and cooled, followed by grinding to obtain 75 g of a zinc-modified 
salicylic acid resin as powder. The softening point of the zinc-modified 
resin was 110.degree. C. It will be designated as Resin (A)-3. 
SYNTHESIS EXAMPLE A-4 
A reactor was charged with 6.9 g (0.05 ) of salicylic acid, 0.2 g of 
anhydrous zinc chloride and 10 ml of acetic acid. Thereafter, 46.1 g (0.2 
mole) of p-(.alpha.-methylbenzyl)benzyl chloride was added in portions at 
an internal temperature of 90.degree.-95.degree. C. over 5 hours. After 
completion of the addition, the reaction mixture was heated and a reaction 
was conducted for 3 hours under reflux of the acetic acid. Thereafter, 6.3 
g (0.025 mole) of nickel acetate was added to reaction mixture and the 
acetic acid was allowed to distil out while raising the temperature of the 
reaction mixture. When the temperature reached 150.degree. C., the 
pressure was reduced to a vacuum. The residue was maintained for 1 hour at 
the same temperature and pressure. The softening point of a 
nickel-modified salicyclic acid resin was 102.degree. C. It will be 
designated as Resin (A)-4. 
SYNTHESIS EXAMPLE A-5 
(i) Synthesis of Salicylic Acid Resin 
A glass-made reactor was charged with 27.6 g (0.2 mole) of salicylic acid, 
109 g (0.8 mole) of benzyl ethyl ether and as a catalyst, 1.3 g of 
p-toluenesulfonic acid. After condensing them at 160.degree.-170.degree. 
C. for 3 hours, the reaction mixture was heated further to 180.degree. C. 
at which the reaction was continued further for 2 hours. In the course of 
the reaction, 34 g of ethanol was distilled out. At the same temperature, 
the reaction product was immediately poured into an enameled shallow pan 
and was then left over. The resinous reaction product was solidified, 
thereby obtaining 95 g of a clear, reddish brown resin. The softening 
point of the thus-obtained resin was 52.degree. C. 
(ii) Synthesis of Multivalent-Metal-Modified Salicyclic Acid Resin 
Ten grams of the above resin were placed in a flask and were then heated 
and molten at 150.degree.-160.degree. C. A mixture of 3.3 g of zinc 
benzoate and 2 g of ammonium bicarbonate, which had been obtained in 
advance, was gradually added under stirring to the molten resin over 30 
minutes. The resultant mixture was then stirred at 155.degree.-165.degree. 
C. for 1 hour to complete the reaction. After completion of the reaction, 
the molten resin was taken out, cooled and then ground, so that 120 g of a 
zinc-benzoate-modified salicylic acid resin was obtained as powder. The 
softening point of the zinc-modified resin was 79.degree. C. It will be 
designated as Resin (A)-5. 
SYNTHESIS EXAMPLE A-6 
(i) Synthesis of Salicylic Acid Resin 
A glass-made reactor was charged with 27.6 g (0.2 mole) of salicylic acid, 
83 g (0.5 mole) of 3,5-dimethylbenzyl ethyl ether and as a catalyst, 0.75 
g of anhydrous zinc chloride. After condensing them at 
150.degree.-160.degree. C. for 4 hours, the reaction mixture was heated 
further to 170.degree. C. and the reaction was continued further for 2 
hours at the same temperature. The internal temperature was then cooled to 
100.degree. C. and 200 ml of toluene was added to dissolve the contents. 
After the dissolution, 500 ml of warm water was added, the resultant 
mixture was stirred for 20 minutes at 95.degree.-100.degree. C., and a 
water layer was removed. This warm-water washing and separation procedure 
was repeated two more times so that unreacted salicylic acid was removed. 
The solvent was thereafter caused to distil out, and the condensation 
product was cooled to obtain 68 g of a clear, reddish brown resin. Its 
softening point was 58.degree. C. 
(ii) Synthesis of Multivalent-Metal-Modified Salicylic Acid Resin 
Ten grams of the above resin were dispersed in 100 g of water which 
contained 0.65 g of caustic soda. The dispersion was heated to 70.degree. 
C. under stirring so as to dissolve the resin. While maintaining the 
temperature of the resultant solution at 45.degree.-50.degree. C., a 
solution which had been prepared in advance by dissolving 1.2 g of 
anhydrous zinc chloride (purity: 90%) in 30 ml of water was added dropwise 
under stirring over 30 minutes. 
A white precipitate was formed. After continuously stirring the reaction 
mixture at the same temperature for 2 hours, the precipitate was collected 
by filtration, washed with water and then dried to obtain 9.8 g of white 
powder. It will be designated as Resin (A)-6. 
SYNTHESIS EXAMPLE A-7 
A glass-made reactor was charged with 27.6 g (0.2 mole) of salicylic acid, 
54 g (0.5 mole) of benzyl alcohol and as catalysts, 0.8 g of anhydrous 
zinc chloride and 0.8 g of p-toluenesulfonic acid. After condensing them 
at 130.degree.-140.degree. C. for 4 hours, the reaction mixture was heated 
further to 160.degree. C. and the reaction was continued further for 2 
hours at the same temperature. The internal temperature was then cooled to 
100.degree. C. and 200 ml of toluene was added to dissolve the contents. 
After the dissolution, 500 ml of warm water was added, the resultant 
mixture was stirred for 20 minutes at 95.degree.-100.degree. C., and a 
water layer was removed. This warm-water washing and separation procedure 
was repeated two more times so that unreacted salicylic acid was removed. 
The solvent was thereafter caused to distil out, and the condensation 
product was cooled to obtain 70 g of a clear, pale reddish brown resin. 
Its softening point was 46.degree. C. 
(ii) Synthesis of Multivalent-Metal-Modified Salicylic Acid Resin 
Ten grams of the above resin was dispersed in 100 g of water which 
contained 0.9 g of caustic soda. The dispersion was heated to 70.degree. 
C. under stirring so as to dissolve the resin. While maintaining the 
temperature of the resultant solution at 45.degree.-50.degree. C., a 
solution which had been prepared in advance by dissolving 1.7 g of 
anhydrous zinc chloride (purity: 90%) in 30 ml of water was added dropwise 
under stirring over 30 minutes. 
A white precipitate was formed. After continuously stirring the reaction 
mixture at the same temperature for 2 hours, the precipitate was collected 
by filtration, washed with water and then dried to obtain 10.5 g of white 
powder. It will be designated as Resin (A)-7. 
SYNTHESIS EXAMPLE A-8 
(i) Synthesis of salicylic acid resin 
A glass-made reactor was charged with 27.6 g (0.2 mole) of salicylic acid, 
24.4 g (0.2 mole) of .alpha.-methylbenzyl alcohol and as a catalyst, 3.0 g 
of p-toluenesulfonic acid. They were condensed at 150.degree.-160.degree. 
C. for 3 hours while causing nitrogen gas to flow through the reactor. 
Then, 48.8 g (0.4 mole) of .alpha.-methylbenzyl alcohol was added dropwise 
over 5 hours at the same temperature. The temperature was thereafter 
raised to 170.degree.-180.degree. C., at which aging was conducted for 3 
hours. At the same temperature, the reaction product was immediately 
poured into an enameled shallow pan and was then left over. The resinous 
reaction product was solidified, thereby obtaining 86 g of a clear, pale 
yellow resin. The weight average molecular weight of the resin thus 
obtained was 750 and its softening point was 54.degree. C. 
(ii) Synthesis of Multivalent-Metal-Modified Salicylic Acid Resin 
Twenty-five grams of the above resin were placed in a flask and were then 
heated and molten at 150.degree.-160.degree. C. A mixture of 6.8 g of zinc 
benzoate and 4 g of ammonium bicarbonate, which had been obtained in 
advance, was gradually added under stirring to the molten resin over 30 
minutes. The resultant mixture was then stirred at 155.degree.-165.degree. 
C. for 1 hour to complete the reaction. After completion of the reaction, 
the molten resin was taken out, cooled and then ground, so that 27 g of a 
zinc-benzoate-modified salicyclic acid resin was obtained as powder. The 
softening point of the zinc-modified resin was 78.degree. C. It will be 
designated as Resin (A)-8. 
SYNTHESIS EXAMPLE A-9 
A reactor was charged with 48 g (0.09 mole) of a 20 wt. % aqueous solution 
of sodium carbonate and 21.2 g (0.1 mole) of 
2,4-dimethyl-.alpha.-methylbenzyl bromide. They was reacted at 100.degree. 
C. for 20 hours. When the reaction mixture was left over after completion 
of the reaction, it cooled down and separated into two layers. The lower 
water layer was removed to obtain the upper organic layer. Yield: 14.5 g. 
It was found to have the following composition by gas chromatography. 
______________________________________ 
2,4-Dimethyl-.alpha.-methylbenzyl alcohol 
87.5 wt. % 
Di-(2,4-dimethyl-.alpha.-methylbenzyl) ether 
11.9 wt. % 
Others 0.6 wt. % 
______________________________________ 
Using the benzyl compounds, a metal-modified salicylic acid co-condensation 
resin was next produced in the following manner. A reactor was charged 
with 3.45 g (0.025 mole) of salicylic acid, 14.5 g of the above benzyl 
compounds and as a catalyst, 0.09 g of aluminum chloride. While causing 
nitrogen gas to flow through the reactor, the resultant mixture was 
heated. Distillation of water started at 120.degree. C. While guiding the 
distilled water to the outside of the reaction system, the reaction 
mixture was heated further and maintained at 150.degree. C. The reaction 
was conducted at the same temperature for 7 hours to complete the 
co-condensation reaction. After completion of the reaction, the reaction 
mixture was immediately taken out of the reactor to obtain 16.2 g of a 
co-condensation resin of salicylic acid. Its average molecular weight was 
780. The co-condensation resin was then added to a solution of 1.38 g 
(0.013 mole) of sodium carbonate in 100 ml of water. The resultant mixture 
was heated to 70.degree. C. under stirring, whereby the co-condensation 
resin was dissolved. The temperature of the solution was then lowered to 
30.degree. C., followed by a dropwise addition of a solution, which had 
been prepared in advance by dissolving 4.3 g (0.015 mole) of zinc sulfate 
heptahydrate in 30 ml of water, over 30 minutes. A white precipitate was 
formed. After continuously stirring the reaction mixture at the same 
temperature for 2 hours, the precipitate was collected by filtration, 
washed with water and then dried to obtain 16.5 g of white powder. It will 
be designated as Resin (A)-9. 
SYNTHESIS EXAMPLE B-1 
A glass-made reactor was charged with 27.6 g (0.2 mole) of salicylic acid, 
48.8 g (0.4 mole) of benzyl methyl ether and as catalysts, 0.76 g of 
p-toluenesulfonic acid and 0.76 g of anhydrous zinc chloride. They were 
condensed at 125.degree.-135.degree. C. for 3 hours while causing nitrogen 
gas to flow through the reactor. The reaction temperature was thereafter 
raised to 145.degree. C., at which the reaction was continued further for 
2 hours. The internal temperature was cooled down to 70.degree. C., 
followed by an addition of 150 ml of 1,2-dichloroethane. The resultant 
mixture was then cooled down to room temperature. Thereafter, 7.5 g of 96% 
sulfuric acid was charged and under vigorous stirring, 83.2 g (0.8 mole) 
of styrene was added dropwise at 20.degree.-30.degree. C. over 5 hours. 
The reaction mixture was then aged at the same temperature for 5 hours to 
complete the reaction. After pouring 60 g of water into the reaction 
mixture under stirring, the resultant mixture was left over so that the 
mixture was allowed to separate into layers. The average molecular weight 
of a resin thus obtained was 1380. The lower solvent layer was charged 
into a separate glass-made reactor, followed by addition of 20 g of 28% 
aqueous ammonia and 8.1 g (0.1 mole) of zinc oxide. The resultant mixture 
was then stirred for 1 hour at room temperature. The mixture was 
thereafter heated and a reaction was conducted at 60.degree.-70.degree. C. 
for 1 hour. The reaction mixture was then heated to distill out the 
solvent. The internal temperature was raised to 150.degree. C., and the 
residue was then degasified for 30 minutes in a vacuum of 20 mmHg to 
obtain 156 g of a zinc-modified salicylic acid resin in a clear, reddish 
brown form (yield: stoichiometric). 
The softening point of the resin was 85.degree. C. It will be designated as 
Resin (B)-1. 
SYNTHESIS EXAMPLE B-2 
A reactor was charged with 27.6 g (0.2 mole) of salicylic acid, 40.8 g (0.3 
mole) of p-methyl-.alpha.-methylbenzyl alcohol, 100 ml of 
monochlorobenzene and as a catalyst, 0.7 g of anhydrous zinc chloride. 
They were reacted for 5 hours under reflux of the solvent. In the course 
of the reaction, the distilled water was removed by a water separator. 
After the reaction, 300 ml of warm water was added and the resultant 
mixture was stirred for 20 minutes at 90.degree. C. or higher, and the 
upper water layer was removed. This water-washing and separation procedure 
was repeated two more times to remove unreacted salicylic acid. Then, 10 g 
of concentrated sulfuric acid was poured into the monochlorobenzene 
solution which had been chilled to 5.degree. C. To the resultant mixture, 
31.2 g (0.3 mole) of styrene was added dropwise at 5.degree.-10.degree. C. 
over 7 hours. After the reaction, the reaction mixture was aged for 3 
hours at the same temperature. The weight average molecular weight of the 
resin was 1150 at that time. The resin was added with 1500 ml of water, 
followed by a dropwise addition of 36 g (0.4 mole) of a 45% aqueous 
solution of caustic soda. The resultant mixture was then heated to 
azeotropically distil out the solvent, thereby obtaining an aqueous 
solution in a somewhat turbid state. The aqueous solution was cooled to 
40.degree. C., followed by a dropwise addition of an aqueous solution 
which had been prepared in advance by dissolving 29 g (0.1 mole) of zinc 
sulfate heptahydrate in 200 ml of water. A white precipitate was formed. 
The white precipitate was collected by filtration, washed with water and 
then dried in a vacuum, thereby obtaining 92 g of a zinc-modified 
salicylic acid resin. Its zinc content was found to be 6.78% by an 
elemental analysis. It will be designated as Resin (B)-2. 
SYNTHESIS EXAMPLE B-3 
A zinc-modified salicylic acid co-condensation resin (172 g) of a pale 
reddish brown color was obtained in the same manner as in Synthesis 
Example B-1 except that benzyl methyl ether was replaced by the same 
amount (0.4 mole) of benzyl alcohol and 104 g (1.0 mole) of styrene was 
used instead of 83.2 g (0.8 mole) of styrene. The softening point of the 
resin was 58.degree. C. It will be designated as Resin (B)-3. 
SYNTHESIS EXAMPLE C-1 
(i) Synthesis of Salicylic Acid Resin 
A glass-made reactor was charged with 6.9 g (0.02 mole) of 
3,5-di(4-methylbenzyl)salicylic acid, 50 ml of isopropyl ether and as a 
catalyst, 2.7 g of anhydrous aluminum chloride. The resultant mixture was 
maintained at 50.degree. C. under stirring. At the same temperature, 7.6 g 
(0.06 mole) of benzyl chloride was added dropwise over 8 hours to conduct 
a reaction. After completion of the dropwise addition, the reaction 
mixture was aged for 2 hours at the same temperature and was then poured 
into a dilute aqueous solution of hydrochloric acid. The resultant mixture 
was allowed to separate into layers. The solvent was then distilled out to 
obtain 12.0 g of a reddish brown resin. The weight average molecular 
weight of the thus-obtained resin was 1250, while its softening point was 
65.degree. C. 
(ii) Synthesis of Multivalent-Metal-Modified Salicylic Acid Resin 
Ten grams of the resin obtained in the above step (i) and 0.65 g of caustic 
soda were stirred and dissolved in 200 ml of hot water. While maintaining 
the temperature of the resultant solution at 30.degree.-35.degree. C., a 
solution which had beforehand been prepared by dissolving 2.5 g of zinc 
sulfate heptahydrate in 30 ml of water was added dropwise over 30 minutes. 
A white precipitate was formed. After continuously stirring the mixture 
for 2 hours at the same temperature, the precipitate was collected by 
filtration, washed with water and then dried to obtain 10.5 g of white 
powder (yield: stoichiometric). The powder was a zinc-modified salicylic 
acid resin. As a result of an analysis of its zinc content, the zinc 
content was found to be 4.96%. The resin will be designated as Resin 
(C)-1. 
SYNTHESIS EXAMPLE C-2 
(i) Synthesis of Salicylic Acid Resin 
A glass-made reactor was charged with 5.1 g (0.02 mole) of 5-(.alpha., 
.alpha.-dimethylbenzyl)salicylic acid, 50 ml of nitromethane, and as a 
catalyst, 1.4 g of anhydrous zinc chloride. The resultant mixture was 
maintained at 95.degree. C. under stirring. At the same temperature, 22.5 
g (0.16 mole) of p-methylbenzyl chloride was added dropwise over 10 hours 
to conduct a reaction. After completion of the dropwise addition, the 
reaction mixture was aged for 2 hours at the same temperature to complete 
the reaction. The weight average molecular weight of the thus-obtained 
resin was 2400. 
(ii) Synthesis of Multivalent-Metal-Modified Salicylic Acid Resin 
The reaction product obtained in the above step (i) was added with and 
dissolved in 75 ml of toluene. Dilute aqueous ammonia was then added 
dropwise at 70.degree.-80.degree. C. to adjust the pH to 6. Thereafter, 
the resultant mixture was added with 0.81 g (0.01 mole) of zinc oxide and 
then stirred at 70.degree.-80.degree. C. for 1 hour to complete the 
reaction. After completion of the reaction, the lower water layer was 
drawn out and the organic layer was concentrated under heat. The resultant 
molten resin was taken out, cooled and then ground, thereby obtaining 23 g 
of a zinc-modified salicylic acid resin as powder. The softening point of 
the zinc-modified resin was 86.degree. C. It will be designated as Resin 
(C)-2. 
SYNTHESIS EXAMPLE C-3 
(i) Synthesis of Salicyclic Acid Resin 
A glass-made reactor was charged with 5.4 g (0.02 mole) of 
3-tert-butyl-5-phenylsalicylic acid, 30 ml of glacial acetic acid, and as 
a catalyst, 1.4 g of anhydrous zinc chloride. The resultant mixture was 
heated under stirring and maintained under reflux. Then, 12.4 g (0.08 
mole) of 2,4-dimethylbenzyl chloride was added dropwise over 6 hours to 
conduct a reaction. After completion of the dropwise addition, the 
reaction mixture was aged for 2 hours under reflux to complete the 
reaction. The weight average molecular weight of the thus-obtained resin 
was 1680. 
(ii) Synthesis of Multivalent-Metal-Modified Salicylic Acid Resin 
Following the procedure of Synthesis Example C-2, 15 g of a zinc-modified 
salicylic acid resin was obtained as powder from the reaction product 
obtained in the above step (i). The softening point of the zinc-modified 
resin was 94.degree. C. It will be designated as Resin (C)-3. 
SYNTHESIS EXAMPLE C-4 
(i) Synthesis of Salicylic Acid Resin 
Charged were 5.50 g (0.02 mole) of 1-hydroxy-2-carboxy-4-benzylnaphthalene, 
50 ml of 1,2-dichloroethane, and as a catalyst, 2.7 g of anhydrous 
aluminum chloride. The resultant mixture was maintained at 70.degree. C. 
under stirring. Then, 5.2 g (0.03 mole) of benzyl bromide was added 
dropwise over 6 hours to conduct a reaction. After completion of the 
dropwise addition, the reaction mixture was aged for 2 hours at the same 
temperature and then poured into dilute hydrochloric acid. The resultant 
mixture was allowed to separate into layers. The lower organic layer was 
concentrated to obtain 8.2 g of a reddish brown resin. The weight average 
molecular weight of the resin was 720. 
(ii) Synthesis of Multivalent-Metal-Modified Salicylic Acid Resin 
To the resin obtained in the above step (i), a mixture of 3.2 g (0.01 mole) 
of zinc benzoate and 2.4 g (0.03 mole) of ammonium bicarbonate was slowly 
added at 150.degree.-160.degree. C. The resultant mixture was then stirred 
for 1 hour at 155.degree.-165.degree. C. to complete the reaction. After 
completion of the reaction, the resultant molten resin was taken out, 
cooled and ground to obtain 23 g of a zinc-benzoate-modified salicylic 
acid resin as powder. The softening point of the zinc-modified resin was 
108.degree. C. It will be designated as Resin (C)-4. 
EXAMPLE A-1 
Twenty-five grams of a 20% aqueous solution of polyvinyl alcohol containing 
5 mole % of sodium 2-acrylamido-2-methylpropanesulfonate (average 
polymerization degree: 300, saponification degree: 90%) and 135.7 g of 
water were mixed in advance, and the pH of the resultant aqueous solution 
was adjusted to 8.0. Into the thus-prepared aqueous solution, 100 g of 
fine powder of Resin (A)-1 obtained in Synthesis Example A-1 was added. 
After stirring the resultant mixture into a slurry, it was processed for 3 
hours in a sand grinder which contained as a grinding medium glass beads 
having a diameter of 1 mm, thereby obtaining a white aqueous suspension 
(solids: 40 wt. %) whose average particle size was 2.4 .mu.m. 
EXAMPLE A-2 
An ethylene-sulfonic acid-vinyl acetate copolymer containing 3 mole % 
ethylenesulfonic acid was saponified with caustic soda, thereby obtaining 
polyvinyl alcohol (average polymerization degree: 300) which contained 
sulfonic acid groups in a proportion equivalent to 3 mole % along with 1 
mole % of acetyl groups. 
Into an aqueous solution (pH 8.4) which had been obtained in advance by 
mixing 50 g of a 20% aqueous solution of the polyvinyl alcohol containing 
sulfonic acid groups with 90 g of water, 100 g of Resin (A)-2 obtained in 
Synthesis Example A-2 was added. After stirring the resultant mixture into 
a slurry, it was dispersed for 5 hours under water cooling in an attritor 
(manufactured by Mitsui Miike Engineering Corporation; contained zirconium 
media of 5 mm diameter) so that a white aqueous suspension (solids: 45 wt. 
%, average particle size: 2.3 .mu.m) was obtained. 
EXAMPLE A-3 
Sulfonated polyvinyl alcohol was obtained by adding polyvinyl alcohol to 
80% sulfuric acid (maintained at 0.degree. C.), reacting them to each 
other, neutralizing the reaction product and then purifying the 
thus-neutralized reaction product. The sulfonated polyvinyl alcohol 
contained sulfonic acid groups in a proportion equivalent to 5 mole % of 
the whole monomer units along with 10 mole % of acetyl groups. An aqueous 
solution obtained in advance by mixing 85 g of water with 25 g of a 20% 
aqueous solution of the sulfonated polyvinyl alcohol was heated to 
90.degree. C, followed by an addition of 100 g of Resin (A)-3 obtained in 
Synthesis Example A-3. After emulsifying and dispersing the resultant 
mixture at a high speed by a homomixer (manufactured by Tokushu Kika Kogyo 
Co., Ltd.), the mixture was cooled down to room temperature so that a 
white aqueous suspension containing 50 wt. % of solids (average particle 
size: 2.1 .mu.m) was obtained. 
EXAMPLE A-4 
Into an aqueous solution obtained by mixing 15 g of a 20% aqueous solution 
of polyvinyl alcohol containing 5 mole % of ethylenesulfonic acid (average 
polymerization degree: 250, saponification degree: 88%) and 6.7 g of a 30% 
aqueous solution of sodium salt of sulfonated polystyrene with 140.8 g of 
water, 100 g of fine powder of Resin (A)-4 obtained in Synthesis Example 
A-4 was added. After stirring the resultant mixture into a slurry, the 
slurry was processed for 2 hours in a sand mill which contained as a 
grinding medium glass beads having a diameter of 1 mm, thereby obtaining a 
white aqueous suspension (solid content: 40 wt. %, average particle size: 
2.4 .mu.m). 
EXAMPLE A-5 
Into an aqueous solution which had been prepared by mixing 25 g of a 20% 
aqueous solution of the sodium salt of sulfated polystyrene (molecular 
weight: 10000, sulfonation degree: 70%) with 135.7 g of water and then 
adjusting its pH to 8.0, 100 g of fine powder of Resin (A)-1 obtained in 
Synthesis Example A-1 was added. In the same manner as in Example A-1, a 
white aqueous suspension having an average particle size of 2.1 .mu.m 
(solid content: 40 wt. %) was obtained. 
EXAMPLE A-6 
Into a mixture (adjusted to pH 8.5 with dilute aqueous ammonia) of 30 g of 
a 30% aqueous solution of the NH.sub.4 salt of sulfonated polystyrene 
("Chemistat 65000", trade name; product of Sanyo Chemical Industries, 
Ltd.) and 88 g of water, 100 g of fine powder of Resin (A)-2 obtained in 
Synthesis Example A-2 was added. After stirring the resultant mixture into 
a slurry, the slurry was dispersed in the same manner as in Example A-2 so 
that a white aqueous suspension (solid content: 45 wt. %, average particle 
size: 1.9 .mu.m) was obtained. 
EXAMPLE A-7 
Into an aqueous solution which had been obtained by mixing 10 g of a 20% 
aqueous solution of polyvinyl alcohol containing 5 mole % of 
ethylenesulfonic acid (average polymerization degree: 250, saponification 
degree: 88%) and 5 g of a 30% aqueous solution of poly(sodium 
styrenesulfonate) ("OKS-3376", trade name; product of The Nippon Synthetic 
Chemical Industry Co., Ltd.) with 112.1 g of water, 100 g of fine powder 
of Resin (A)-3 obtained in Synthesis Example A-3 was added. The resultant 
mixture was processed for 1.5 hours in a sealed sand grinder (Dyno mill) 
which contained as a grinding medium glass beads having a diameter of 0.8 
mm, thereby obtaining a white aqueous suspension having an average 
particle size of 2.4 .mu.m (solid content: 48 wt. %). 
EXAMPLE A-8 
Into an aqueous solution which had been obtained by mixing 13.3 g of a 30% 
aqueous solution of the sodium salt of a sulfonated styrene-maleic acid 
copolymer ("S-SMA-1000", trade name; product of Arco Chemical Company) 
with 117.8 g of water, 100 g of Resin (A)-4 obtained in Synthesis Example 
A-4 was added. The resultant mixture was processed for 2 hours in a 
horizontal sand mill which contained as a grinding medium glass beads 
having a diameter of 1.0 mm, thereby obtaining a white aqueous suspension 
having an average particle size of 2.3 .mu.m (solid content: 45 wt. %). 
EXAMPLE A-9 
A white aqueous suspension having an average particle size of 2.5 .mu.m 
(solid content: 40 wt. %) was obtained in the same manner as in Example 
A-1 except for the use of Resin (A)-5 in lieu of Resin (A)-1. 
EXAMPLE A-10 
A white aqueous suspension (solid content: 45 wt. %, average particle size: 
2.4 .mu.m) was obtained in the same manner as in Example A-2 except for 
the use of Resin (A)-6 in lieu of Resin (A)-2. 
EXAMPLE A-11 
A white aqueous suspension having an average particle size of 2.5 .mu.m 
(solid content: 40 wt. %) was obtained by conducting stirring and slurry 
formation in the same manner as in Example A-3 except for the use of Resin 
(A)-2 instead of Resin (A)-3 and then effecting dispersing processing in 
the same manner as in Example A-1. 
EXAMPLE A-12 
A white aqueous suspension having an average particle size of 2.1 .mu.m 
(solid content: 50 wt. %) was obtained in the same manner as in Example 
A-3 except for the use of Resin (A)-9 in place of Resin (A)-3. 
EXAMPLE A-13 
A white aqueous suspension (solid content: 40 wt. %, average particle size: 
2.1 .mu.m) was obtained in the same manner as in Example A-5 except for 
the use of Resin (A)-7 in place of Resin (A)-1. 
EXAMPLE A-14 
A white aqueous suspension (solid content: 45 wt. %, average particle size: 
1.9 .mu.m) was obtained in the same manner as in Example A-6 except for 
the use of Resin (A)-8 in lieu of Resin (A)-2. 
EXAMPLE A-15 
A white aqueous suspension having an average particle size of 2.1 .mu.m 
(solid content: 45 wt. %) was obtained in the same manner as in Example 
A-8 except for the use of Resin (A)-1 in place of Resin (A)-4. 
EXAMPLE A-16 
A white aqueous suspension having an average particle size of 2.1 .mu.m 
(solid content: 40 wt. %) was obtained by conducting stirring and slurry 
formation in the same manner as in Example A-4 except for the use of Resin 
(A)-8 instead of Resin (A)-4 and then effecting dispersing processing in 
the same manner as in Example A-1. 
EXAMPLE A-17 
Into an aqueous solution which had been obtained by mixing 20 g of a 20% 
aqueous solution of polyvinyl alcohol (average polymerization degree: 300, 
saponification degree: 90%) containing 5 mole % of sodium 
2-acrylamide-2-methylpropanesulfanate units and 3.3 g of a 30% aqueous 
solution of the sodium salt of a sulfonated styrene condensation resin 
("NARLEX-D82", trade name; product of Kanebo-NSC, Ltd.) with 157 g of 
water, 100 g of Resin (A)-5 obtained in Synthesis Example A-5 was added. 
After the resultant mixture was stirred into a slurry, the slurry was 
processed for 2 hours in the horizontal sand mill employed in Example A-8, 
thereby obtaining a white aqueous suspension having an average particle 
size of 2.2 .mu.m (solid content: 40 wt. %). 
EXAMPLE A-18 
A white aqueous suspension having an average particle size of 2.2 .mu.m 
(solid content: 48 wt. %) was obtained in the same manner as in Example 
A-7 except for the use of Resin (A)-9 in place of Resin (A)-3. 
EXAMPLE A-19 
Into an aqueous solution which had been obtained by mixing 12 g of a 20% 
aqueous solution of sulfonated polyvinyl alcohol (which contained sulfonic 
acid groups in a proportion equivalent to 5 mole % of the whole monomer 
units along with 10 mole % of acetyl groups) and 10 g of a 30% aqueous 
solution of the sodium salt of a styrene-maleic acid copolymer with 114 g 
of water, 100 g of Resin (A)-2 obtained in Synthesis Example A-2 was 
added. After stirring the resultant mixture into a slurry, it was 
dispersed for 5 hours under water cooling in the attritor employed in 
Example A-2 so that a white aqueous suspension (solid content: 45 wt. %, 
average particle size: 2.6 .mu.m) was obtained. 
EXAMPLE A-20 
Fine powder (100 g) of Resin (A)-7 was added to an aqueous solution (pH 
8.4) which had been prepared in advance by mixing 50 g of a 20% aqueous 
solution of acrylamide-modified polyvinyl alcohol (average polymerization 
degree: 1000, the degree of modification: 10 mole %; "PC-100", trade name; 
product of Denki Kagaku Kogyo Kabushiki Kaisha) with 90 g of water. After 
stirring the resultant mixture into a slurry, the slurry was dispersed for 
5 hours under water cooling in the attritor employed in Example A-2. A 
white aqueous suspension (solid content: 45 wt. %, average particle size: 
2.3 .mu.m) was obtained. 
EXAMPLE A-21 
Resin (A)-8 (100 g) was added to an aqueous solution which had been 
obtained by mixing 20 g of a 20% aqueous solution of acrylamide-modified 
polyvinyl alcohol (average polymerization degree: 1000 the degree of 
modification: 10 mole %) and 5 g of a 30% aqueous solution of poly(sodium 
styrenesulfonate) (molecular weight: 5000, sulfonation degree:90%) with 
139 g of water. After stirring the resultant mixture into a slurry, a 
white aqueous suspension having an average particle size of 2.2 .mu.m 
(solid content: 40 wt. %) was obtained in the same manner as in Example 
A-2. 
COMATIVE EXAMPLE A-1 
A brown aqueous suspension having an average particle size of 2.8 .mu.m was 
obtained in the same manner as in Example A-1 except that instead of the 
polyvinyl alcohol containing sulfonic acid groups, the sodium salt of a 
formaldehyde condensation product of naphthalenesulfonic acid was used in 
the same amount. 
COMATIVE EXAMPLE A-2: 
Formation of an aqueous suspension was conducted in the same manner as in 
Example A-1 except that instead of the polyvinyl alcohol containing 
sulfonic acid groups, completely-saponified polyvinyl alcohol ("POVAL 
117", trade name; product of Kuraray Co., Ltd.) was used in the same 
amount. Considerable foaming took place upon stirring the mixture into a 
slurry prior to the processing of the slurry in the sand grinder and 
during the processing in the sand grinder. Even after the processing, it 
took 24 hours until foams disappeared. The work efficiency was hence 
extremely inferior. The thus-formed aqueous suspension was a viscous white 
aqueous suspension having an average particle size of 2.6 .mu.m. 
COMATIVE EXAMPLE A-3 
Fine powder (100 g) of Resin (A)-2 obtained in Synthesis Example A-2 was 
dispersed in 120 g of water in which 10 g of sodium ligninsulfonate 
("Orzan CD", trade name; product of ITT Rayonier Company) had been 
dissolved, thereby forming a slurry. The slurry was then processed in a 
sand grinder in the same manner as in Example A-1, so that a brown aqueous 
suspension (solid content: 47.8 wt. %, average particle size: 2.5 .mu.m) 
was obtained. 
COMATIVE EXAMPLE A-4 
A brown aqueous suspension having an average particle size of 2.8 .mu.m was 
obtained in the same manner as in Comparative Example A-1 except for the 
substitution of Resin (A)-5 for Resin (A)-1 used in Comparative Example 
A-1. 
COMATIVE EXAMPLE A-5 
Formation of an aqueous suspension was conducted in the same manner as in 
Comparative Example A-2 except for the replacement of Resin (A)-1 employed 
in Comparative Example A-2 to Resin (A)-5. Considerable foaming took place 
upon stirring the mixture into a slurry prior to the processing of the 
slurry in the sand grinder and during the processing in the sand grinder. 
Even after the processing, it took 24 hours until foams disappeared. The 
work efficiency was hence extremely inferior. The thus-formed aqueous 
suspension was a viscous white aqueous suspension having an average 
particle size of 2.6 .mu.m. 
COMATIVE EXAMPLE A-6 
A brown aqueous suspension (solid content: 47.8 wt. %, average particle 
size: 2.5 .mu.m) was obtained in the same manner as in Comparative Example 
A-3 except for the use of Resin (A)-6 instead of Resin (A)-2. 
COMATIVE EXAMPLE A-7 
When processing was conducted in the same manner as in Comparative Example 
A-5 except that the sodium salt of a polycarboxylic acid ("Quinflow 540", 
trade name for the sodium salt of a copolymer of C.sub.5 fraction and 
maleic anhydride; product of Nippon Zeon Co., Ltd.) was used in the same 
amount instead of the polyvinyl alcohol containing sulfonic acid groups, 
the state of dispersion was poor and the resultant mixture turned to a 
solid paste as a whole. It was hence unable to take it out as an aqueous 
suspension. 
COMATIVE EXAMPLE A-8 
Into a glass-made reactor, were charged 170 g of p-phenylphenol, 22.5 g of 
80% paraformaldehyde, 2.0 g of p-toluenesulfonic acid and 200 g of 
benzene. While heating them under stirring and distilling the resulting 
water out of the system azeotropically with the benzene, they were reacted 
for 2 hours at 70.degree.-80.degree. C. After the reaction, 320 g of a 10% 
aqueous solution of sodium hydroxide was added and the benzene was 
distilled out by steam distillation. The resultant mixture was cooled, 
followed by a dropwise addition of dilute sulfuric acid. A 
p-phenylphenol-formaldehyde polymer thus precipitated was collected by 
filtration, washed with water, and then dried, thereby obtaining 176 g of 
white powder. 
In an aqueous solution of 12 g of a 25% aqueous solution of the sodium salt 
of a polycarboxylic acid ("Polystar OM", trade name; product of Nippon Oil 
& Fats Co., Ltd.) in 160 g of water, 100 g of powder of the 
p-phenylphenol-formaldehyde polymer was dispersed to form a slurry. The 
slurry was processed in a sand grinder in the same manner as in Example 
A-1, thereby obtaining a white aqueous suspension (solid content: 39.6 wt. 
%, average particle size: 25 .mu.m). 
Properties of the aqueous suspensions obtained separately in Examples 
A-1-A-21 and Comparative Examples A-1-A-8 were evaluated. Results are 
summarized in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Ex. A-1 
Ex. A-2 
Ex. A-3 
Ex. A-4 
Ex. A-5 
Ex. A-6 
Ex. A-7 
Ex. A-8 
Ex. 
Ex. 
__________________________________________________________________________ 
A-10 
Properties of aqueous suspension 
Hue reflectivity (%) 
83.1 83.1 83.2 82.9 83.1 82.9 83.1 83.1 83.2 83.1 
Viscosity (cps) 
16.8 19.4 17.2 18.5 16.0 21.5 23.2 19.0 17.7 19.3 
High temperature 
storage stability 
Filtration 26 29 30 21 29 33 31 19 31 29 
time (sec) 
Particle size change (.mu.m) 
Before test 2.4 2.3 2.1 2.4 2.1 1.9 2.4 2.3 2.5 2.4 
After test 2.4 2.3 2.1 2.5 2.1 2.0 2.4 2.4 2.5 2.4 
Properties of aqueous coating formulation 
Viscosity (cps) 
460 480 470 480 490 480 490 500 470 490 
Amount of agglomerates 
0.01 0.01 0.02 0.003 
0.01 0.005 
0.01 0.004 
0.01 0.01 
formed * (%) 
Properties as pressure-sensitive copying paper 
Color producing ability 
Color production rate (%) 
Initial (J.sub.1) 
42.9 43.5 44.1 43.5 43.0 43.3 42.8 44.1 43.3 43.3 
Final (J.sub.2) 
47.5 47.4 47.6 47.5 47.6 47.1 47.8 48.0 48.3 48.5 
Whiteness of color 
82.1 82.0 82.0 82.1 82.1 82.0 81.9 82.1 82.1 82.1 
developing sheet (F) 
Light yellowing 
5.1 4.9 5.0 5.0 3.9 4.5 4.7 4.1 2.1 2.2 
resistance (.DELTA.K) 
NOx yellowing 
2.5 2.4 2.4 2.3 2.7 2.5 2.7 2.4 2.5 2.5 
resistance (.DELTA.L) 
__________________________________________________________________________ 
Ex. A-11 
Ex. A-12 
Ex. A-13 
Ex. A-14 
Ex. A-15 
Ex. A-16 
Ex. A-17 
Ex. A-18 
Ex. 
Ex. 
__________________________________________________________________________ 
A-20 
Properties of aqueous suspension 
Hue reflectivity (%) 
83.1 83.0 83.1 83.0 83.2 83.0 83.1 83.1 83.1 83.1 
Viscosity (cps) 
18.4 19.7 18.7 18.2 18.7 17.1 17.5 18.5 18.1 19.5 
High temperature 
storage stability 
Filtration 30 27 25 22 26 25 23 23 20 28 
time (sec) 
Particle size change (.mu.m) 
Before test 2.5 2.1 2.0 1.9 2.3 2.1 2.2 2.1 2.3 2.3 
After test 2.6 2.1 2.1 2.0 2.3 2.1 2.2 2.2 2.3 2.3 
Properties of aqueous coating formulation 
Viscosity (cps) 
480 530 480 520 510 490 490 550 520 530 
Amount of agglomerates 
0.01 0.02 0.02 0.01 0.01 0.01 0.01 0.005 
0.005 
0.01 
formed * (%) 
Properties as pressure-sensitive copying paper 
Color producing ability 
Color production rate (%) 
Initial (J.sub.1) 
43.3 43.0 43.1 43.0 42.9 43.0 43.0 43.1 43.0 43.1 
Final (J.sub.2) 
48.1 47.9 48.0 48.0 47.8 48.0 48.1 48.3 48.0 48.0 
Whiteness of color 
82.1 82.1 82.0 82.2 82.2 82.1 82.1 82.2 82.1 82.0 
developing sheet (F) 
Light yellowing 
2.2 2.1 2.1 2.2 2.2 2.2 2.2 2.1 2.2 2.1 
resistance (.DELTA.K) 
NOx yellowing 
2.7 2.7 2.7 2.5 2.7 2.6 2.4 2.4 2.4 2.7 
resistance (.DELTA.L) 
__________________________________________________________________________ 
Comp. 
Comp. 
Comp. 
Comp. 
Comp. 
Comp. 
Comp. 
Comp. 
Ex. A-21 
Ex. A-1 
Ex. A-2 
Ex. A-3 
Ex. A-4 
Ex. A-5 
Ex. A-6 
Ex. 
Ex. 
__________________________________________________________________________ 
A-8 
Properties of aqueous suspension 
Hue reflectivity (%) 
83.0 75.8 83.0 60.0 73.1 83.1 60.8 -- 80.7 
Viscosity (cps) 18.5 65.0 110.0 
73.0 65.0 125.0 
78.0 -- 24.0 
High temperature 
storage stability 
Filtration 24 230 75 480 250 90 420 -- 52 
time (sec) 
Particle size change (.mu.m) 
Before test 2.2 2.6 2.7 2.5 2.8 2.6 2.5 -- 2.5 
After test 2.3 7.3 2.8 3.1 5.8 2.7 3.3 -- 2.7 
Properties of aqueous coating formulation 
Viscosity (cps) 490 610 (viscous) 
720 720 (viscous) 
700 -- 490 
1720 1820 
Amount of agglomerates 
0.01 1.80 0.06 0.52 1.30 0.05 0.64 -- 0.02 
formed * (%) 
Properties as pressure-sensitive copying paper 
Color producing ability 
Color production rate (%) 
Initial (J.sub.1) 43.0 40.1 43.8 36.8 40.5 43.1 36.8 -- 39.4 
Final (J.sub.2) 48.0 46.7 47.4 43.4 46.2 47.5 43.1 -- 44.8 
Whiteness of color 
82.2 76.8 82.0 75.3 76.2 82.1 74.8 -- 81.9 
developing sheet (F) 
Light yellowing 2.2 16.8 5.0 11.0 11.8 2.1 8.6 -- 16.5 
resistance (.DELTA.K) 
NOx yellowing 2.5 11.5 2.6 19.7 11.4 2.6 18.4 -- 36.2 
resistance (.DELTA.L) 
__________________________________________________________________________ 
* (measured by marron mechanical stability testing machine.) 
EXAMPLE B-1 
Fine powder (100 g) of Resin (B)-1 obtained in Synthesis Example B-1 was 
added to an aqueous solution which had been prepared in advance by mixing 
25 g of a 20% aqueous solution of poly(sodium styrenesulfonate) (molecular 
weight: 5000, sulfonation degree: 65%) with 137.5 g of water and then 
adjusting its pH to 8.0. The resultant mixture was stirred into a slurry, 
followed by processing for 3 hours in a sand grinder which contained as a 
grinding medium glass beads having a diameter of 1 mm. A white aqueous 
suspension (solid content: 40 wt. %) having an average particle size of 
2.5 .mu.m was obtained. 
EXAMPLE B-2 
A white aqueous suspension (solid content: 50 wt. %, average particle size: 
2.4 .mu.m) was obtained in the same manner as in Example A-6 except for 
the use of Resin (B)-2 in place of Resin (A)-2. 
EXAMPLE B-3 
Fine powder (100 g) of Resin (B)-2 obtained in Synthesis Example B-2 was 
added to an aqueous solution of 5 g of the sodium salt of a sulfonated 
styrenemaleic anhydride copolymer ("S-SMA 3000", trade name; product of 
Arco Chemical Company) in 130 g of water. The resultant mixture was then 
converted into a slurry. The slurry was then processed in a sand grinder 
in the same manner as in Example B-1 to obtain a white aqueous 
suspension,(solid content: 44.7 wt. %, average particle size: 3.4 .mu.m). 
EXAMPLE B-4 
A white aqueous suspension (solid content: 50 wt. %, average particle size 
2.7 .mu.m) was obtained in the same manner as in Example B-3 except for 
the use of the sodium salt of a sulfonated styrene condensation resin 
("NARLEX-D82", trade name; product of Kanebo-NSC, Ltd.) in place of the 
sodium salt of the sulfonated styrene-maleic anhydride copolymer. 
EXAMPLE B-5 
Fine powder (100 g) of Resin (B)-1 obtained in Synthesis Example B-1 was 
added to an aqueous solution which had been prepared in advance by mixing 
50 g of a 20% aqueous solution of polyvinyl alcohol containing 5 mole % of 
ethylenesulfonic acid (average polymerization degree: 250. saponification 
degree: 88%) with 135 g of water. The resultant mixture was stirred into a 
slurry, followed by dispersion in the same manner as in Example B-1 A 
white aqueous suspension (solid content: 40wt. %) having an average 
particle size of 2 3 .mu.m was obtained. 
EXAMPLE B-6 
Resin (B)-2 (100 g) was added to an aqueous solution which had been 
obtained by mixing 13.3 g of a 30% aqueous solution of the sodium salt of 
a sulfonated styrene condensation resin ("NARLEX-D82", trade name; product 
of Kanebo-NSC, Ltd.) with 117.8 g of water. The resultant mixture was 
processed for 2 hours in a horizontal sand mill in which glass beads 
having a diameter of 1.0 mm were contained as a grinding medium, so that a 
white aqueous suspension (solid content: 50 wt. %) having an average 
particle size of 2.5 .mu.m was obtained. 
EXAMPLE B-7 
Fine powder (100 g) of Resin (B)-1 obtained in Synthesis Example B-1 was 
added to an aqueous solution which had been prepared by mixing 20 g of a 
20% aqueous solution of polyvinyl alcohol containing 5 mole % of 
ethylenesulfonic acid (average polymerization degree: 250, saponification 
degree: 88%) and 3.3 g of a 30% aqueous solution of poly(ammonium 
styrenesulfonate) with 110 g of water. The resultant mixture was processed 
for 1.5 hours in a sealed sand grinder (Dynomill) which contained as a 
grinding medium glass beads having a diameter of 0.8 mm. A white aqueous 
suspension (solid content: 45 wt. %) having an average particle size of 
2.0 .mu.m was obtained. 
EXAMPLE B-8 
A white aqueous suspension (solid content: 40 wt. %, average particle size: 
2.6 .mu.m) was obtained in the same manner as in Example A-1 except for 
the use of Resin (B)-1 in place of Resin (A)-1. 
EXAMPLE B-9 
A white aqueous suspension (solid content: 45 wt. %, average particle size: 
2.6 .mu.m) was obtained in the same manner as in Example A-2 except for 
the use of Resin (B)-2 in place of Resin (A)-2. 
EXAMPLE B-10 
A white aqueous suspension having a solid content of 50 wt. % (average 
particle size: 2.1 .mu.m) was obtained in the same manner as in Example 
A-3 except for the use of Resin (B)-3 in place of Resin (A)-3. 
EXAMPLE B-11 
Fine powder (100 g) of Resin (B)-1 obtained in Synthesis Example B-1 was 
added to an aqueous solution which had been prepared by mixing 25 g of a 
20% aqueous solution of polyvinyl alcohol containing 5 mole % of 
ethylenesulfonic acid (average polymerization degree: 250, saponification 
degree: 88%) and 10 g of a 30% aqueous solution of poly(sodium 
styrenesulfonate) with 135 g of water. After stirring the resultant 
mixture into a slurry, the slurry was processed for 2 hours in a same mill 
which contained as a grinding medium glass beads having a diameter of 1 
mm. A white aqueous suspension (solid content: 40 wt. %, average particle 
size: 2.2 .mu.m) was obtained. 
EXAMPLE B-12 
A white aqueous suspension having an average particle size of 2.6.mu.(solid 
content: 40 wt. %) was obtained in the same manner as in Example B-1 
except for the use of acrylamide-modified polyvinyl alcohol (average 
polymerization degree: 1000, the degree of modification: 10 mole %; 
"PC-100", trade name; product of Denki Kagaku Kogyo Kabushiki Kaisha) in 
place of the poly(sodium styrenesulfonate). 
EXAMPLE B-13 
Fine powder (100 g) of Resin (B)-2 was added to an aqueous solution (pH 
8.4) which had been prepared in advance by mixing 50 g of a 20% aqueous 
solution of acrylamide-modified polyvinyl alcohol (average polymerization 
degree: 600, the degree of modification: 4 mole %; "NP-10K", trade name; 
product of Denki Kagaku Kogyo Kabushiki Kaisha) with 90 g of water. After 
stirring the resultant mixture into a slurry, the slurry was dispersed for 
5 hours under water cooling in the attritor employed in Example A-2. A 
white aqueous suspension (solid content: 45 wt. %, average particle size: 
2.6 .mu.m) was obtained. 
EXAMPLE B-14 
A white aqueous suspension having a solid content of 50 wt. % (average 
particle size: 2.1 .mu.m) was obtained in the same manner as in Example 
B-10 except for the use of acrylamide-modified polyvinyl alcohol 
(polymerization degree: 600, the degree of modification: 2 mole %; 
"NP-15", trade name; product of Denki Kagaku Kogyo Kabushiki Kaisha) in 
place of the sulfonated polyvinyl alcohol. 
EXAMPLE B-15 
A white aqueous suspension (solid content: 40 wt. %, average particle size: 
2.2 .mu.m) was obtained in the same manner as in Example B-11 except for 
the use of acrylamide-modified polyvinyl alcohol (average polymerization 
degree: 1000, the degree of modification: 2 mole %) in lieu of the 
polyvinyl alcohol containing sulfonic acid. 
EXAMPLE B-16 
A white aqueous suspension having an average particle size of 2.1 .mu.m 
(solid content: 40 wt. %) was obtained in the same manner as in Example 
A-17 except for the use of Resin (B)-2 in lieu of Resin (A)-5. 
EXAMPLE B-17 
Resin (B)-2 (100 g) was added to an aqueous solution which had been 
obtained by mixing 20 g of a 20% aqueous solution of acrylamide-modified 
polyvinyl alcohol (average polymerization degree: 1000, the degree of 
modification: 10 mole %) and 5 g of a 30% aqueous solution of poly(sodium 
styrenesulfonate) (molecular weight: 5000, sulfonation degree: 90%) with 
139 g of water. After stirring the resultant mixture into a slurry, a 
white aqueous suspension having an average particle size of 2.1 .mu.m 
(solid content: 40 wt. %) was obtained in the same manner as in Example 
A-2. 
EXAMPLE B-18 
A white aqueous suspension having an average particle size of 2.3 .mu.m 
(solid content: 40 wt. %) was obtained in the same manner as in Example 
B-16 except for the use of acrylamide-modified polyvinyl alcohol (average 
polymerization degree: 600, the degree of modification: 2 mole %) instead 
of the acrylamide-modified polyvinyl alcohol (average polymerization 
degree: 1000, the degree of modification: 10 mole %). 
EXAMPLE B-19 
Resin (B)-3 (100 g) was added to an aqueous solution which had been 
obtained by mixing 20 g of a 20% aqueous solution of polyvinyl alcohol 
containing 3 mole % of ethylenesulfonic acid (average polymerization 
degree: 300, saponification degree: 88%) and 5 g of a 30% aqueous solution 
of poly(sodium styrenesulfonate) (molecular weight: 10000, sulfonation 
degree: 94%) with 139 g of water. After stirring the resultant mixture 
into a slurry, a white aqueous suspension having an average particle size 
of 2.1 .mu.m (solid content: 40 wt. %) was obtained in the same manner as 
in Example B-1. 
EXAMPLE B-20 
Resin (B)-2 (100 g) obtained in Synthesis Example B-2 was added to an 
aqueous solution which had been obtained by mixing 20 g of a 20% aqueous 
solution of sulfonated polyvinyl alcohol (which contained sulfonic acid 
groups in a proportion equivalent to 5 mole % of the whole monomer units 
along with 10 mole % of acetyl groups) and 5 g of a 30% aqueous solution 
of poly(sodium styrenesulfonate) (molecular weight: 5000, sulfonation 
degree: 90%) with 139 g of water. After stirring the resultant mixture 
into a slurry, a white aqueous suspension (solid content: 40 wt. %, 
average particle size: 2.1 .mu.m) was obtained in the same manner as in 
Example A-8. 
EXAMPLE B-21 
A white aqueous suspension having an average particle size of 2.0 .mu.m 
(solid content: 45 wt. %) was obtained in the same manner as in Example 
B-7 except for the use of poly(sodium styrenesulfonate) (molecular weight: 
3000, sulfonation degree: 60%). 
COMATIVE EXAMPLE B-1 
A brown aqueous suspension having an average particle size of 2.8 .mu.m was 
obtained in the same manner as in Comparative Example A-1 except for the 
use of Resin (B)-1 instead of Resin (A)-1. 
COMATIVE EXAMPLE B-2 
Formation of an aqueous suspension was conducted in the same manner as in 
Comparative Example A-2 except for the use of Resin (B)-1 instead of Resin 
(A)-1. Considerable foaming took place upon processing the resultant 
mixture in the sand grinder. Even after the processing, it took 24 hours 
until foams disappeared. The work efficiency was hence extremely inferior. 
The thus-formed aqueous suspension was a viscous white aqueous suspension 
having an average particle size of 2.7 .mu.m. 
COMATIVE EXAMPLE B-3 
A brown aqueous suspension (solid content: 47.8 wt. %, average particle 
size: 3.0 .mu.m) was obtained in the same manner as in Comparative Example 
A-3 except for the use of Resin (B)-2 instead of Resin (A)-2. 
Properties of the aqueous suspensions obtained separately in Examples 
B-1-B-21 and Comparative Examples B-1-B-3 were evaluated. Results are 
summarized in Table 2. 
TABLE 2 
__________________________________________________________________________ 
Ex. B-1 
Ex. B-2 
Ex. B-3 
Ex. B-4 
Ex. B-5 
Ex. B-6 
Ex. 
Ex. 
__________________________________________________________________________ 
B-8 
Properties 
Hue reflectivity (%) 
82.5 82.6 82.5 82.5 83.0 83.1 83.2 82.5 
of aqueous 
Viscosity (cps) 21.3 41.5 52.5 48.5 18.1 18.9 17.9 18.5 
suspension 
High- 
Filtration 30 55 45 63 29 26 18 30 
temper- 
time (sec) 
ature 
Par- Before 
2.5 2.4 3.4 2.7 2.3 2.5 2.0 2.6 
storage 
ticle 
test 
stability 
size After 2.5 2.5 3.7 2.7 2.3 2.5 2.1 2.6 
change 
test 
(.mu.m) 
Properties 
Viscosity (cps) 560 540 610 580 490 550 510 480 
of aqueous 
Amount of agglomerates 
0.01 0.02 0.02 0.03 0.01 0.02 0.005 
0.02 
coating 
formed* (%) 
formulation 
Properties 
Color 
Color 
Initial (J.sub.1) 
44.3 44.1 43.8 43.9 43.1 43.5 43.0 
44.1 
as pro- produc- 
Final (J.sub.2) 
47.3 48.5 48.4 48.4 48.1 48.3 48.0 47.3 
pressure- 
ducing 
tion 
sensitive 
abil- 
rate 
copying 
ity (%) 
paper Whiteness of color 
82.1 82.1 82.1 82.2 82.0 82.0 82.0 82.1 
developing sheet (F) 
Light yellowing 3.5 3.7 3.8 3.6 2.0 2.1 2.1 3.6 
resistance (.DELTA.K) 
NOx yellowing 1.8 2.0 2.0 1.8 2.6 2.6 2.4 1.8 
resistance (.DELTA.L) 
__________________________________________________________________________ 
Ex. B-9 
Ex. B-10 
Ex. B-11 
Ex. B-12 
Ex. B-13 
Ex. B-14 
Ex. 
Ex. 
__________________________________________________________________________ 
B-16 
Properties 
Hue reflectivity (%) 
82.6 82.5 82.5 82.5 82.6 82.6 82.5 83.0 
of aqueous 
Viscosity (cps) 20.3 16.5 17.5 17.4 24.0 15.5 14.8 17.1 
suspension 
High- 
Filtration 31 25 18 28 31 25 17 22 
temper- 
time (sec) 
ature 
Par- Before 
2.6 2.1 2.2 2.6 2.6 2.1 2.2 2.1 
storage 
ticle 
test 
stability 
size After 2.6 2.2 2.2 2.6 2.6 2.2 2.2 2.2 
change 
test 
(.mu.m) 
Properties 
Viscosity (cps) 470 470 480 490 530 480 510 490 
of aqueous 
Amount of agglomerates 
0.02 0.03 0.01 0.01 0.03 0.02 0.01 0.005 
coating 
formed* (%) 
formulation 
Properties 
Color 
Color 
Initial (J.sub.1) 
43.9 44.4 44.2 44.4 44.0 44.2 44.4 43.0 
as pro- produc- 
Final (J.sub.2) 
47.4 46.9 47.2 47.1 47.3 46.9 47.2 48.3 
pressure- 
ducing 
tion 
sensitive 
abil- 
rate 
copying 
ity (%) 
paper Whiteness of color 
82.1 82.1 82.2 82.1 82.1 82.1 82.2 82.0 
developing sheet (F) 
Light yellowing 3.7 3.8 3.5 3.6 3.7 3.9 3.4 2.1 
resistance (.DELTA.K) 
NOx yellowing 2.0 2.0 1.9 1.9 2.0 1.9 2.0 2.5 
resistance (.DELTA.L) 
__________________________________________________________________________ 
Comp. 
Comp. 
Comp. 
Ex. B-17 
Ex. B-18 
Ex. B-19 
Ex. B-20 
Ex. B-21 
Ex. B-1 
Ex. 
Ex. 
__________________________________________________________________________ 
B-3 
Properties 
Hue reflectivity (%) 
83.0 83.1 83.0 83.0 83.2 76.1 82.4 60.3 
of aqueous 
Viscosity (cps) 17.5 17.3 17.7 17.6 17.2 53.0 85.4 68.4 
suspension 
High- 
Filtration 21 23 20 25 23 180 40 480 
temper- 
time (sec) 
ature 
Par- Before 
2.1 2.3 2.1 2.1 2.0 2.8 2.7 3.0 
storage 
ticle 
test 
stability 
size After 2.3 2.3 2.1 2.1 2.1 4.5 3.0 5.1 
change 
test 
(.mu.m) 
Properties 
Viscosity (cps) 495 500 497 505 510 590 760 610 
of aqueous 
Amount of agglomerates 
0.005 
0.005 
0.005 
0.005 
0.005 
0.55 0.01 0.63 
coating 
formed* (%) 
formulation 
Properties 
Color 
Color 
Initial (J.sub.1) 
43.1 43.0 43.2 43.0 43.0 39.5 44.3 36.8 
as pro- produc- 
Final (J.sub.2) 
48.3 48.5 48.3 48.1 48.1 43.3 46.8 43.1 
pressure- 
ducing 
tion 
sensitive 
abil- 
rate 
copying 
ity (%) 
paper Whiteness of color 
82.0 82.0 82.1 82.1 82.0 78.4 82.0 76.3 
developing sheet (F) 
Light yellowing 2.1 2.1 2.1 2.1 2.1 10.8 3.6 8.4 
resistance (.DELTA.K) 
NOx yellowing 2.7 2.7 2.7 2.5 2.4 9.4 1.8 14.5 
resistance (.DELTA.L) 
__________________________________________________________________________ 
*(measured by marron mechanical stability testing machine.) 
EXAMPLE C-1 
A white aqueous suspension having an average particle size of 2.5 .mu.m 
(solid content: 40 wt. %) was obtained in the same manner as in Example 
A-1 except for the use of Resin (C)-1 in place of Resin (A)-1. 
EXAMPLE C-2 
A white aqueous suspension (solid content: 45 wt. %, average particle size: 
2.1 .mu.m) was obtained in the same manner as in Example A-2 except for 
the use of Resin (C)-2 in place of Resin (A)-2. 
EXAMPLE C-3 
A white aqueous suspension having a solid content of 50 wt. % (average 
particle size: 2.1 .mu.m) was obtained in the same manner as in Example 
A-3 except for the use of Resin (C)-3 in place of Resin (A)-3. 
EXAMPLE C-4 
A white aqueous suspension (solid content: 40 wt. %, average particle size: 
2.2 .mu.m) was obtained in the same manner as in Example B-11 except for 
the use of Resin (C)-4 in place of Resin (B)-1. 
EXAMPLE C-5 
A white aqueous suspension (solid content: 40 wt. %, average particle size: 
2.3 .mu.m) was obtained in the same manner as in Example A-5 except for 
the use of Resin (C)-1 in place of Resin (A)-1. 
EXAMPLE C-6 
A white aqueous suspension (solid content: 45 wt. %, average particle size: 
1.9 .mu.m) was obtained in the same manner as in Example A-6 except for 
the use of Resin (C)-2 in place of Resin (B)-2. 
EXAMPLE C-7 
A white aqueous suspension having an average particle size of 2.4 .mu.m 
(solid content: 48 wt. %) was obtained in the same manner as in Example 
A-7 except for the use of Resin (C)-3 in place of Resin (A)-3. 
COMATIVE EXAMPLE C-1 
A brown aqueous suspension having an average particle size of 2.8 .mu.m was 
obtained by following the procedure of Comparative Example A-1 except for 
the use of Resin (C)-1 in place of Resin (A)-1. 
COMATIVE EXAMPLE C-2 
Formation of an aqueous suspension was conducted in the same manner as in 
Comparative Example A-2 except for the use of Resin (C)-1 instead of Resin 
(A)-1. Considerable foaming took place upon conducting the stirring and 
slurry formation prior to the processing in the sand grinder and during 
the processing in the sand grinder. Even after the processing, it took 24 
hours until foams disappeared. The work efficiency was hence extremely 
inferior. The thus-formed aqueous suspension was a viscous white aqueous 
suspension having an average particle size of 2.7 .mu.m. 
COMATIVE EXAMPLE C-3 
A brown aqueous suspension (solid content: 47.8 wt. %, average particle 
size: 3.0 .mu.m) was obtained in the same manner as in Comparative Example 
A-3 except for the use of Resin (C)-2 instead of Resin (A)-2. 
Properties of the aqueous suspensions obtained separately in Examples 
C-1-C-7 and Comparative Examples C-1-C-3 were evaluated. Results are 
summarized together with evaluation results of the suspension of 
Comparative Example A-8 in Table 3. 
TABLE 3 
__________________________________________________________________________ 
Comp. 
Ex. C-1 
Ex. C-2 
Ex. C-3 
Ex. C-4 
Ex. C-5 
Ex. C-6 
Ex. 
Ex. 
__________________________________________________________________________ 
A-8 
Properties 
Hue reflectivity (%) 
83.2 82.8 82.7 82.7 83.1 82.7 82.7 80.7 
of aqueous 
Viscosity (cps) 16.3 18.5 20.1 18.5 17.5 19.1 15.0 24.0 
suspension 
High- 
Filtration 31 30 27 18 32 35 16 52 
temper- 
time (sec) 
ature 
Par- Before 
2.5 2.1 2.1 2.2 2.3 1.9 2.4 2.5 
storage 
ticle 
test 
stability 
size After 2.5 2.1 2.2 2.2 2.4 2.0 2.4 2.7 
change 
test 
(.mu.m) 
Properties 
Viscosity (cps) 470 480 470 480 470 460 480 490 
of aqueous 
Amount of agglomerates 
0.01 0.01 0.02 0.005 
0.03 0.03 0.005 
0.02 
coating 
formed* (%) 
formulation 
Properties 
Color 
Color 
Initial (J.sub.1) 
43.8 44.4 
42.8 43.1 44.1 43.8 44.1 39.4 
as pro- produc- 
Final (J.sub.2) 
47.4 47.4 48.0 47.5 47.5 47.5 48.0 44.8 
pressure- 
ducing 
tion 
sensitive 
abil- 
rate 
copying 
ity (%) 
paper Whiteness of color 
82.0 82.0 82.0 82.1 82.0 82.0 82.0 81.9 
developing sheet (F) 
Light yellowing 3.6 3.7 3.7 3.8 3.6 3.7 3.8 16.5 
resistance (.DELTA.K) 
NOx yellowing 2.0 2.1 2.1 2.0 1.9 2.0 2.0 36.2 
resistance (.DELTA.L) 
__________________________________________________________________________ 
Comp. 
Comp. 
Comp. 
Ex. C-1 
Ex. 
Ex. 
__________________________________________________________________________ 
C-3 
Properties 
Hue reflectivity (%) 
76.1 82.4 60.1 
of aqueous 
Viscosity (cps) 76.0 124.0 
69.0 
suspension 
High- 
Filtration 210 85 485 
temper- 
time (sec) 
ature 
Par- Before 
2.7 2.7 3.0 
storage 
ticle 
test 
stability 
size After 6.4 2.7 4.5 
change 
test 
(.mu.m) 
Properties 
Viscosity (cps) 590 (viscous) 
720 
of aqueous 1640 
coating 
Amount of agglomerates 
1.80 0.09 0.48 
formulation 
formed* (%) 
Properties 
Color 
Color 
Initial (J.sub.1) 
39.8 44.0 36.8 
as pro- produc- 
Final (J.sub.2) 
46.0 47.0 43.4 
pressure- 
ducing 
tion 
sensitive 
abil- 
rate 
copying 
ity (%) 
paper Whiteness of color 
78.1 82.0 76.3 
developing sheet (F) 
Light yellowing 11.8 3.9 8.6 
resistance (.DELTA.K) 
NOx yellowing 10.8 2.1 18.4 
resistance (.DELTA.L) 
__________________________________________________________________________ 
*(measured by marron mechanical stability testing machine.) 
As is apparent from the foregoing, it has become feasible to prepare an 
aqueous suspension of a multivalent-metal-modified salicylic acid resin, 
said suspension having the below-described advantages, by using the 
above-described aionic water-soluble high-molecular compound as a 
dispersant upon preparation of the aqueous suspension. 
(1) The suspension is colored very little and has a high degree of 
whiteness. 
(2) The suspension is dispersed in an extremely stable state and develops 
little coagulation or sedimentation even when stored for a long period of 
time at high temperatures. 
(3) Stable aqueous suspensions can be obtained over a wide pH range. They 
are less affected by an acid, alkali, salt and/or the like , which are 
contained in the multivalent-metal-modified salicylic acid. 
(4) Thickening and/or foaming occur very little during the formation of the 
aqueous suspension. 
(5) The aqueous coating formulation, which has been obtained by mixing the 
suspension with other components of the aqueous coating formulation and is 
suitable for use in the production of pressure-sensitive copying papers, 
is excellent in both thermal and mechanical stability. 
(6) Upon preparation of the aqueous coating formulation and during coating 
work, foaming takes place very little so that the efficiency of the 
coating work is superb. 
(7) The aqueous suspension provides excellent pressure-sensitive copying 
papers free of the problem that the dispersant itself would be yellowed 
and deteriorated upon exposure to light or during storage and would hence 
be deteriorated in quality.