Process for the production of reactive microgel and resin composition containing the microgel

Process for the production of reactive microgels having a functional group on a surface of each of fine particles of the microgels, which comprises reacting fine microgel particles (A) synthesized from a monomer having a polymerizable double bond by emulsion polymerization using, as an emulsifier, a compound containing tertiary ammonium salt, with a compound (B) having, in the molecule, an epoxy group to react with the tertiary ammonium salt and at least one reactive functional group other than the epoxy group, and hardenable resin composition comprising the above reactive microgels and a resin.

FIELD OF THE INVENTION 
This invention relates to a process for the production of reactive 
microgels having a reactive group such as a carbon-carbon double bond, 
hydroxyl group, carboxyl group, or the like and a resin composition 
containing the reactive microgels. More specifically, this invention 
relates to a process for the production of reactive microgels to 
contribute to improvement of properties such as photosensitivity, water 
resistance, solvent resistance, etc., a process for the production of 
reactive microgels useful as a high-resolution, high-reactivity resist 
material for manufacture of printed circuit boards, machine plates for 
printing, semiconductor elements, etc., a coating composition, a printing 
ink and a reactive additive, and a resin composition containing the 
microgels. 
PRIOR ART OF THE INVENTION 
Microgels are gelled or crosslinked polymer particles having about 
colloidal size, e.g. a diameter of 0.001 to 10 .mu.m, and in general, have 
recently attracted attention as a new polymeric material synthesized by 
emulsion polymerization. In particular, since W. Funke synthesized 
microgels having a reactive group on the surface in 1975, the microgels 
have attracted remarkable attention and many polymer researchers have made 
studies thereof [W. Obrecht, U. Seitz, W. Funke, Am. Chem. Soc., Div. 
Polym. Chem. Prepr. 16(1), 149 (1975)]. In the process of Funke, the 
microgels are synthesized by emulsion-polymerizing a monomer having at 
least two double bonds under very moderate conditions and modifying the 
unreacted double bonds on the surface with other reagent to convert them 
to various reactive functional groups. As examples, there have been 
proposed processes for conversion to a hydroxyl group with borane, to a 
halogen group with hydrogen halide, to a carboxyl group with ozone, and 
the like. Since, however, reactions in these processes do not take place 
in a water-existing system, it is required that microgels should be 
separated from an aqueous dispersion, purified, dried, and then reacted 
with various reagents by dispersing them in an organic solvent such as 
DMF, pyridine, etc., whereby a reactive functional group is introduced. 
Thus, these processes take too much time and require very high cost. The 
use of the microgels as an industrial material is therefore limited. 
Yamazaki, et al have made an attempt to synthesize reactive microgels in a 
one-step reaction [Yamazaki, Hattori, Hyomen (Surface) 1987, 25, 86]. 
However, the functional groups that can be introduced by the above reaction 
are extremely limited in kind, and in particular, since functional groups 
having a carbon-carbon double bond react due to an attack of radical in 
emulsion polymerization, it has been difficult to synthesize reactive 
microgels having a double bond. 
Azuma (Japanese Patent Laid-Open Publication No. 80942/1989) discloses a 
process for the production of photosensitive microgel particles having a 
structure in which a cinnamic acid ester is formed on the surface of each 
of the microgel particles. This process comprises separating 
(meth)acrylatebased microgel particles formed in an aqueous medium from 
the aqueous medium, and then reacting them with a cinnamic acid or a 
derivative thereof in an organic solvent. However, this process has a 
problem that the procedure for isolation of the microgel particles from 
the aqueous medium is complicated. There is also a problem that the 
organic solvent for esterification is expensive. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a novel process for the 
production of reactive microgels having a reactive functional group on the 
surface. 
It is another object of this invention to provide a novel process for the 
production of reactive microgels, which makes it possible to attach 
various functional groups quantitatively. 
It is further another object of this invention to provide a novel process 
for the production of reactive microgels, which makes it possible to 
attach reactive functional groups to fine microgel particles formed by 
emulsion polymerization in an aqueous medium without separating the fine 
microgel particles from the aqueous medium. 
It is further another object of this invention to provide a novel 
hardenable resin composition containing reactive microgels. 
It is still further another object of this invention to provide a novel 
photosetting or heat-setting resin composition containing reactive 
microgels. 
It is yet another object of this invention to provide a novel water-soluble 
photohardenable resin composition. 
According to this invention, there are provided: 
a process for the production of reactive microgels having a functional 
group on the surface of each of fine particles of the reactive microgels, 
which comprises reacting fine microgel particles (A) synthesized from a 
monomer having a polymerizable double bond by emulsion polymerization 
using, as an emulsifier, a compound containing tertiary ammonium salt, 
with a compound (B) having, in its molecule, an epoxy group to react with 
the tertiary ammonium salts and at least one reative functional group 
other than the epoxy group, and 
a hardenable resin composition comprising the above reactive microgels and 
a resin. 
DETAILED DESCRIPTION OF THE INVENTION 
The present inventor has made a diligent study and found an addition 
reaction which takes place even in water, and the use of this finding has 
led to a finding of a process for quantitatively attaching a functional 
group other than an epoxy group, e.g. an unsaturated double bond, hydroxyl 
group, carboxyl group, etc., without isolating fine microgel particles 
from an aqueous dispersion. 
In this invention, concerning monomers having a polymerizable double bond 
for systhesis of the fine microgel particles (A), examples of 
monofunctional monomers are as follows. 
(a) (meth)acrylic compounds: 
C.sub.1 -C.sub.18 alkyl esters of (meth)acrylic acid such as methyl 
(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl 
(meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl 
(meth)acrylate, lauryl (meth)acrylate, etc.; glycidyl (meth)acrylate; 
C.sub.2 -C.sub.8 alkenyl esters of (meth)acrylic acids such as allyl 
(meth)acrylate, etc.; C.sub.2 -C.sub.8 hydroxyalkyl esters of 
(meth)acrylic acids such as hydroxyethyl (meth)acrylate, hydroxypropyl 
(meth)acrylate, etc.; C.sub.3 -C.sub.19 hydroxyalkenyl esters of 
(meth)acrylic acids such as allyoxyethyl acrylate, etc.; (meth)acrylic 
acid. 
(b) vinyl aromatic compounds: 
styrene, p-methylstyrene, p-chlorostyrene, etc. 
(c) others: 
(meth)acrylonitrile, methyl isopropenyl ketone, vinyl acetate, vinyl 
propionate, vinyl pivalate, etc. 
Examples of polyfunctional monomers having two or more carbon-carbon double 
bonds useful for three-dimensional crosslinkage within each of the fine 
microgel particles (A) are the following. 
(a) (meth)acrylic compounds: 
tri(meth)acrylic ester of trimethylolpropane, di(meth)acrylic ester of 
glycols, di(meth)acrylic ester of polyol, di(meth)acrylic ester of 
polyurethane, di(meth)acrylic ester of polyester, etc. 
(b) olefin compounds: 
butadiene, isoprene, chloroprene, divinyl benzene, diallyphthalate, etc. 
These unsaturated monomers having polymerizable double bond(s) are suitably 
selected depending upon their physical properties, and they are usable 
alone or in combination. 
The molar ratio between the monofunctional monomer and the polyfunctional 
monomer in use is usually 100:0.1.about.50, preferably 100:0.1.about.10, 
whereby the degree of three-dimensional crosslinkage within each of the 
fine microgel particles is suitably controlled. 
However, it is not essential in this invention to use a polyfunctional 
monomer. That is, a reactive emulsifier is usable as an emulsifier in this 
invention, and the use of a reactive emulsifier can achieve 
three-dimensional crosslinkage within each of the fine mcirogel particles 
(A). 
The compound containing tertiary ammonium salts, usable as an emulsifier 
for synthesis of the fine microgel particles (A), is selected from those 
having a function of an emulsifier, and in general, there are used 
compounds having a tertiary amino group is neutralized into a tertiary 
ammonium salt with acid. 
As the emulsifiers having a lower molecular weight, it is possible to cite 
those prepared by neutralizing reactive monomers having an amino group, 
i.e. tertiary amines--examples thereof are shown below--to tertiary 
ammonium salts with an acid such as hydrochloric acid, nitric acid, 
sulfuric acid, formic acid, acetic acid, propionic acid, butyric acid, 
(meth)acrylic acid, etc.: 
C.sub.6 -C.sub.20 alkyl and alkenyl tertiary amines of dimethyllaurylamine, 
dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, 
diethyllaurylamine, diethylmyristylamine, diethylpalmitylamine, 
diethylstearylamine, etc. 2,2-dimethylaminoethyl (meth)acrylate, 
2,2-diethylaminoethyl (meth)acrylate, etc. 
Further, as polymer emulsifiers, it is also possible to cite those prepared 
by coplymerizing a compound having an amino group such as 
2,2-dimethylaminoethyl (meth)acrylate, 2,2-diethylaminoethyl 
(meth)acrylate, etc., with at least one of the following other compounds, 
e.g. a vinyl monomer, and then neutralizing the resultant copolymer with 
an acid to convert it a tertiary ammonium salt. 
C.sub.1 -C.sub.18 alkyl esters of (meth)acrylates such as methyl 
(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl 
(meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl 
(meth)acrylate, lauryl (meth)acrylate, etc.; glycidyl (meth)acrylate; 
C.sub.2 -C.sub.8 alkenyl esters of (meth)acrylates such as allyl 
(meth)acrylate, etc., C.sub.2 -C.sub.8 hydroxyalkyl esters of 
(meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl 
(meth)acrylate, hydroxybutyl (meth)acrylate, etc; C.sub.3 -C.sub.19 
alkenyloxyalkyl esters of (meth)acrylates such as allyoxylethyl 
(meth)acrylate, etc.; (meth)acrylic acid, etc. 
Furthermore, examples of the emulsifiers include those formed by 
neutralizing amino group-containing polymers, e.g. natural polymers such 
as chitosan, etc., or synthetic polymers such as polyethylene imine, etc., 
with an acid to convert them to quaternay ammonium salts. 
These high-molecular emulsifiers can be used without any change, or after 
polymerizable dobule bonds are introduced by reacting part of their 
tertiary ammonium salts with a compound containing an epoxy group such as 
glycidyl (meth)acrylate, etc., and a tertiary ammonium salt. 
The above high-molecular emulsifiers also have a function to control the 
degree of water-solubility. These emulsifiers are used in an amount of 0.1 
to 80% by weight, preferably 3 to 50% by weight, based on the monomer 
having a polymerizable double bond, and the temperature for the emulsion 
polymerization is between 50.degree. and 95.degree. C., preferably between 
65.degree. and 80.degree. C. The emulsion polymerization is carried out 
under the conditions that the solid content of the monomer and the 
emulsifier in total is 10 to 50% by weight, preferably 15 to 30% by 
weight. In this invention, the fine microgel particles formed by the 
emulsion polymerization usually have a diameter, measured by optical 
scattering method, of 10 to 200 nm. 
A tertiary ammonium salt present on each of the fine microgel particles (A) 
formed as above and the compound (B) having, in the molecule, an epoxy 
group and at least one reactive functional group other than the epoxy 
group are reacted to introduce the reactive functional group into the 
surface of each of the fine microgel particles. Examples of the compound 
(B) include epoxy compounds having an unsaturated double bond such as 
glycidyl (meth)acrylate, N-glycidyl (meth)acrylamide, glycidylallyl ether, 
1,2-epoxy-5-hexene, etc., epoxy compounds having a hydroxyl group such as 
glycidol, etc., epoxy compounds having a carboxyl group such as epoxy 
succinate, etc., and the like. These compounds for the compound (B) are 
suitably selected depending upon desired physical properties, and usable 
alone or in combination. In the reaction with the tertiary ammonium salt 
on the surface of the fine microgel particle, the amount of the compound 
(B) may be 1 to 100 mole % based on the tertiary ammonium salts. 
This reaction is completed by only mixing an epoxy compound with an 
emulsion of the fine microgel particles and stirring the mixture at a 
temperature between 30.degree. and 90.degree. C., preferably between 
60.degree. and 80.degree. C. for 2 hours or more. Namely, this invention 
has an advantage that the fine microgel particles can be reacted even in 
an aqueous dispersion. 
The reactive microgels of this invention are provided as an aqueous 
dispersion or a dispersion thereof in an organic solvent prepared by 
removing whole or part of their water content by azeotropy with benzenes, 
alcohols, ketones, etc. The reactive microgels can be converted to a dry 
form by a usual method, preferably by a method of coagulating the 
microgels, then washing the coagulation product, drying it and milling it 
or by a spray drying method. The microgels can be coagulated by 
salt-precipitation in which sodium chloride is added. 
In the reactive microgels obtained according to the process of this 
invention, the degree of crosslinkage within the fine microgel particle is 
controlled by selection of monomers having a polymerizable double bond, 
etc., whereby the microgel per se can be imparted with a film-forming 
ability and used in a resist material. Further, it is also possible to 
obtain resin compositions having excellent properties by suitably 
selecting degrees of crosslinkage and functional groups on the surface, 
and incorporating the resultant microgels into resins. 
Water-soluble photohardenable resin compositions containing reactive 
microgels obtained according to the process of this invention will be 
explained hereinbelow. 
A photohardenable resin composition containing reactive microgels is 
crosslinked with UV rays, electron beams, etc., after an additive, e.g. a 
photopolymerization initiator, etc., other hydrophilic resin and a 
hydrophilic monomer are added as required. The content of the reactive 
microgels in the photohardenable resin composition is 20 to 90% by weight, 
preferably 40 to 80% by weight, based on a water-soluble resin. The 
crosslinkage can take place by radiation without using any 
photopolymerization initiator. When UV rays are irradiated, however, 
efficiency of crosslinkage can be improved by addition of a suitable 
photopolymerization initiator. Examples of the photopolymerization 
initiator include benzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 
1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 
2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1, etc. These 
photopolymerization initiators are usable in an amount of 0.1 to 10 parts 
by weight based on 100 parts by weight of a resin. Examples of the 
above-mentioned "other hydrophilic resin" include polyvinyl alcohol, 
carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, 
poly(meth)acrylate, casein, gelatin, starch, polyvinyl pyrrolidone, 
poly(meth)acrylamide, chitosan, a polymer containing a quaternary ammonium 
salt, and the like. Examples of the hydrophilic monomer include 
N,N-methylenebis(meth)acrylamide, 1,2-di(meth)acrylamide ethylene glycol, 
N,N-oxymethylenebisacrylamide, (meth)acrylamide, vinyl pyrrolidone, 
2-hydroxyethyl (meth)acrylate, polyoxyethylene (meth)acrylate, 
polyoxyethylene di(meth)acrylate, and the like. Further, to impart the 
resin of this invention with various functions, it is possible to 
incorporate a colorant, extender pigment, lubricant, plasticizer, 
stabilizer, flame retardant, antifoamer, oxidation preventor, sterilizer, 
electrically conductive material, magnetic material, etc. 
According to this invention, there is provided a process for the production 
of microgels, which makes it possible to attach a variety of functional 
groups to the surface of each of fine microgel particles quantitatively 
without isolating the fine microgel particles from an aqueous dispersion 
thereof. 
Further, according to this invention, there is provided a process for the 
production of microgels, in which degree of crosslinkage within each of 
fine microgel particles can be controlled to make the microgels per se 
useful as a resist material. 
According to this invention, there is also provided a resin composition 
containing the microgels formed in the process of this invention. This 
resin composition produces effects on improvement of various properties of 
resin compositions such as photosensitivity, water resistance, solvent 
resistance, etc., by suitably selecting functional groups to be attached 
to the surface of the microgel. For example, a resin composition 
containing the microgels having a (meth)acryl group as a functional group 
on the surface is suitable as a photosensitive material especially for a 
coating composition, ink, photohardenable adhesive, printing substrate, 
machine plate, etc.

The following Examples explain processes for the production of reactive 
microgels and changes in physical properties of resins containing the 
reactive microgels. In Examples, part stands for part by weight, and % for 
% by weight. 
EXAMPLE 1 
Process for the production of reactive microgels 
I. Aqueous solution of cationic polymer emulsifier: 
While 100 parts of butyl methacrylate, 100 parts of 2-dimethylaminoethyl 
methacrylate and 200 parts of 2-propanol were stirred in a 2-liter reactor 
under nitrogen atmosphere, they were heated to 80.degree. C. 1 part of 
azobisisobutyronitrile (to be referred to as AIBN hereinbelow) was added, 
and the mixture was maintained at the above temperature for 1 hour. Then, 
0.2 part of AIBN was added every 30 minutes 5 times while the mixture was 
maintained at 80.degree. C. The resultant reaction product was further 
maintained at 80.degree. C. for 3 hours after the final addition of AIBN 
to complete polymerization. The product was cooled to room temperature, 
then 38.2 parts of acetic acid was added, and the mixture was stirred for 
a while. Then, 1,000 parts of water was added, and the mixture was heated 
to remove the 2-propanol by azeotropy, whereby an aqueous solution of a 
cationic polymer emulsifier was obtained. Further, part of the water was 
removed by distillation to adjust this emulsifier solution to a solid 
content of 20%. 
II. Reactive microgels: 
While 27 parts of styrene, 3 parts of divinyl benzene, 75 parts of an 
aqueous solution of the cationic polymer emulsifier and 185 parts of 
deionized water were stirred in a 500-milliliter reactor under a nitrogen 
atmosphere, they were heated to 65.degree. C. 8 Parts of a 3% aqueous 
solution of 2,2-azobis(2-amidinopropane) dihydrochloride (to be referred 
to as AAPD hereinbelow) was added, and immediately thereafter, the mixture 
was heated to 80.degree. C. and maintained at this temperature for 2 
hours. Then, 2 parts of a 3% aqueous solution of AAPD was added, and after 
the addition, the resultant reaction mixture was maintained at 80.degree. 
C. to complete polymerization (for nonreactive fine microgel particles). 
The particle diameter thereof was measured by an optical scattering method 
to show about 50 nm. The resultant microgel aqueous dispersion was cooled 
to room temperature, and left to stand overnight. Then, 2.7 parts of 
glycidyl methacrylate was added and the mixture was heated to 80.degree. 
C. under air. The resultant reaction mixture was maintained at 80.degree. 
C. for 4 hours to complete the reaction (for reactive microgels). 
EXAMPLES 2-3 and COMATIVE EXAMPLES 1-2 
The reactive microgels having a methacryl group on the surface, synthesized 
in Example 1, were added to a nonphotosensitive acrylic resin (Example 2) 
and to a photosenstive acrylic resin (Example 3) to examine changes in 
tensile strength. The cationic polymer synthesized in Example 1-I was used 
as the nonphotosensitive acrylic resin above. Further, as the 
photosensitive acrylic resin, there was used a polymer prepared by 
modifying 5% of the quaternary ammonium groups of the above cationic 
polymer with glycidyl methacrylate. 
______________________________________ 
Component Weight (g) 
______________________________________ 
Aqueous solution of 20% acrylic resin 
10 
Aqueous dispersion of 15% reactive microgel 
3.3 
Photopolymerization initiator (Darocure 2959, 
0.075 
product name, manufactured by Merk Co.. 
______________________________________ 
The above components were mixed and heated to 60.degree. C. The mixture was 
stirred until it was homogeneously mixed as a whole, and maintained at 
60.degree. C. The homogeneous mixture was charged into a box made of 
Teflon and having interior length and width sizes of 9 cm and a depth of 3 
mm, and the box was placed on a horizontal base, covered with a shading 
sheet, and left to stand at room temperature until a film was formed on 
the surface. When the film was formed, the box was put into an oven at 
60.degree. C. to dry the film overnight. The resultant dry film had a 
thickness of about 0.2 mm. The film was cut into strips having a width of 
1 cm to measure tensile strength. The above procedure was repeated except 
that the nonreactive microgel particles obtained in Example 1-II were 
added to the above nonphotosensitive acrylic resin or the photosensitive 
acrylic resin, and the resultant films were measured for tensile strength. 
Table 1 shows changes in tensile strength of films obtained by 
incorporating the reactive microgel particles or nonreactive microgel 
particles into the nonphotosensitive acrylic resin or photosensitive 
acrylic resin and subjecting the resultant films to irraidation with 100 
mJ UV rays or no irradiation. 
TABLE 1 
______________________________________ 
Tensile strength 
(kg/cm.sup.2) 
No UV UV 
Sample irradiation 
irradiation 
______________________________________ 
Example 2 (Nonphotosensitive 
10.5 22.9 
resin + reactive microgels) 
Example 3 (Photosensitive 
9.8 102.1 
resin + reactive microgels) 
Comparative Example 1 
(Nonphotosensitive resin) 
10.2 9.5 
(Nonphotosensitive resin + 
8.9 8.8 
nonreactive microgels) 
Comparative Example 2 (Photosensitive 
5.8 52.7 
acrylic resin) 
(Photosensitive resin + 
8.3 64.9 
nonreactive mirogels) 
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EXAMPLE 4 
While 27 parts of styrene, 3 parts of divinyl benzene, 75 parts of an 
aqueous solution of the cationic polymer emulsifier obtained in Example 1 
and 185 parts of deionized water were stirred in a 500-milliliter reactor 
under nitrogen current, they were heated to 80.degree. C. 8 Parts of a 3% 
aqueous solution of AAPD was added, and this temperature of the mixture 
was maintained for 2 hours. Then, 2 parts of a 3% aqueous solution of AAPD 
was added, and thereafter, the resultant reaction mixture was maintained 
at 80.degree. C. to complete the reaction. The resultant aqueous 
dispersion of microgel particles was cooled to room temperature, and left 
to stand overnight. Then, 1.4 parts of glycidol was added, and the mixture 
was maintained under air under heat at 80.degree. C. for 4 hours to give 
reactive microgels containing a hydroxyl group. 
EXAMPLE 5 
Example 4 was repeated except that 2.5 parts of epoxy succinate was used in 
place of 1.4 parts of glycidol, whereby reactive microgels containing a 
carboxyl group were obtained. 
EXAMPLE 6 
Process for the production of reactive microgel 
I. Cationic polymer emulsifier: 
While 100 parts of hexyl methacrylate, 100 parts of 2-dimethylaminoethyl 
methacrylate and 200 parts of 2-propanol were stirred in a 2-liter reactor 
under nitrogen atmosphere, they were heated to 80.degree. C. 1.6 parts of 
AIBN was added, and the mixture was maintained at 80.degree. C. for 2 
hours. Then, 0.4 part of AIBN was added and the resultant reaction mixture 
was maintained at 80.degree. C. for 4 hours to complete polymerization. 
The reaction mixture was cooled to room temperature, then a mixture of 
38.2 parts of acetic acid with 1,000 parts of water was added, and the 
resultant mixture was heated to remove the 2-propanol and water by 
azeotropy and adjust the solid content of the resultant emulsifier 
solution to 20%. 
II. Reactive (photosensitive) cationic polymer emulsifier: 
Glycidyl methacrylate (18.1 parts) was added to the cationic polymer 
emulsifier synthesized in Example 6-I, and the mixture was heated to 
70.degree. C. under air atmosphere and maintained for 2 hours to give a 
photosensitive cationic polymer emulsifier having pendant methacryl 
groups. 
III. Nonreactive microgel particles: 
While 12 parts of butyl methacrylate, 15 parts of ethylhexyl methacrylate, 
3 parts of neopentyl glycol dimethacrylate, 75 parts of an aqueous 
solution of the reactive cationic polymer emulsifier synthesized in 
Example 6-II and 185 parts of deionized water were stirred in a 
500-milliliter reactor under nitrogen atmosphere, they were heated to 
80.degree. C. 8 parts of a 3% aqueous solution of 
azobisamidinopropane-dihydrochloride (to be referred to as AAPD 
hereinbelow) was added, and the mixture was maintained at 80.degree. C. 
for 2 hours. Then, 2 parts of an aqueous solution of 3% AAPD was added. 
After the addition, the reaction mixture was maintained at 80.degree. C. 
for 4 hours to complete polymerization. The diameter of the resultant 
microgel particles was measured by an optical scattering method to show 
about 50 nm. 
IV. Reactive microgels 
An aqueous dispersion of the nonreactive microgel particles synthesized in 
Example 6-III was left to stand overnight, then 2.7 parts of glycidyl 
methacrylate was added, the mixture was heated to 70.degree. C. under air 
atmosphere, and the reaction product was maintained at this temperature 
for 2 hours to complete the reaction. 
V. Evaluation of reactive microgels 
The nonreactive microgel particles of Example 6-III (Comparative Example 3) 
and the reactive microgel particles of Example 6-IV (Example 6) were 
respectively dispersed in the photosensitive cationic polymer emulsifiers 
synthesized in Example 6-II, and then a photopolymerization initiator of 
4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone (Darocure 2959, 
trade name, manufactured by Merk Co.) in an amount of 3% based on the 
dispersions was added to each of the dispersions to form, by a casting 
method, microgel dispersion films having a thickness of about 300 .mu.m. 
The films were irradiated with UV rays at 200 mJ/cm.sup.2. The films were 
immersed in deionized water or methyl ethyl ketone at room temperature for 
3 hours, and their weight increases were examined to evaluate their water 
resistance and solvent resistance. 
In addition, the above procedure was repeated to form a film except that no 
microgel was added, and water resistance and solvent resistance of the 
film were also evaluated as Comparative Example 4. 
Table 2 shows the results. 
TABLE 2 
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Resistance 
Sample to water to solvent 
______________________________________ 
Reference 52% 75% 
Nonphotosensitive microgel 
42% 102% 
Photosensitive microgel 
32% 48% 
______________________________________ 
As is clear in the above Table 2, the nonreactive (nonphotosensitive) 
microgels exhibited improved water resistance but exhibited poorer solvent 
resistance. In contrast, the reactive (photosensitive) microgels were 
excellent both in water resistance and solvent resistance. 
EXAMPLE 7 
While 27 parts of butyl acrylate, 3 parts of ethylene glycol 
dimethacrylate, 75 parts of an aqueous solution of the cationic polymer 
emulsifier synthesized in Example 6-I and 185 parts of deionized water 
were stirred in a 500-milliliter reactor under nitogen current, they were 
heated to 80.degree. C. 8 parts of a 3% aqueous solution of AAPD was 
added, and the mixture was maintained at the above temperature for 2 
hours. Then, 2 parts of a 3% aqueous solution of AAPD was added, and the 
reaction mixture was maintained at 80.degree. C. to complete the reaction. 
The resultant microgel aqueous dispersion was cooled to room temperature 
and left to stand overnight, then 1.4 parts of glycidol was added, and the 
mixture was maintained under air current under heat at 70.degree. C. for 2 
hours to give reactive microgels containing hydroxyl groups. 
EXAMPLE 8 
Example 6 was repeated to form reactive microgels containing carboxyl 
groups except that 2.5 parts of epoxy succinic acid was used in place of 
1.4 parts of glycidol in Example 6-III. 
EXAMPLE 9 AND COMATIVE EXAMPLE 5 
Glycidyl methacrylate (72.4 parts) was added to the photosensitive cationic 
polymer emulsifier synthesized in Example 6-II, and the mixture was 
stirred at 70.degree. C. for 2 hours to react the glycidyl methacrylate 
with all of quaternary ammonium salts, whereby a water-soluble 
photosensitive polymer was prepared. 
2 parts of the water-soluble photosensitive polymer, 40 parts of the 
reactive microgel dispersion (having a solid content of 20%) obtained in 
Example 6-IV and 0.5 part of Darocure 2959 (trade name, manufactured by 
Merk Co.) were mixed and formed into resin sheets having a thickness of 
about 1 mm by a casting method. These resin sheets and commercially 
available sheets (photosensitive resin sheets formed of an acrylic monomer 
having a side chain of acetyl group of partial saponification polyvinyl 
acetate, trade name, NAPP, manufactured by Nippon Paint K.K., Comparative 
Example 5) were irradiated with UV rays at 500 mJ/cm.sup.2, and immersed 
in deionized water at room temperature (25.degree. C.) to examine their 
weight increases. 
Table 3 shows the results. 
TABLE 3 
______________________________________ 
Sample 
Immersing time 
The invention, 
Commercial sheets 
______________________________________ 
1 hour 5% 18% 
2 hours 6% 25% 
3 hours 7% 29% 
4 hours 8% 35% 
______________________________________ 
EXAMPLE 10 
I. The procedure of Example 6 was repeated to form reactive microgels 
except that the amount (12 parts) of butyl methacrylate was changed to 
28.5 parts, and that 15 parts of ethylhexyl methacrylate was changed to 
1.5 parts of ethylene glycol dimethacrylate. 
II. 3% Darocure 2959 (trade name, manufactured by Merk Co.) was added to an 
aqueous dispersion of the reactive microgel obtained above to form 
microgel dispersion films having a thickness of 300 .mu.m. The films were 
irradiated with 1,200 mJ UV rays, and then immersed in deionized water or 
isopropyl alcohol at room temperature (25.degree. C.) to examine their 
weight increases. 
Table 4 shows the results. 
TABLE 4 
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Absorptivity 
Immersing time to water to alcohol 
______________________________________ 
1 hour 5.4 11.2 
2 hours 6.2 17.0 
3 hours 6.2 21.0 
4 hours 6.1 24.0 
______________________________________