Offset ink compositions

Offset ink compositions are disclosed which contain as a vehicle a resin (III) obtainable by the steps of: PA0 (a) copolymerizing 100 parts by weight of a five-membered ring compound having a conjugated double bond, represented by the general formula: ##STR1## (wherein H is hydrogen, R is an alkyl group having 1 to 3 carbon atoms, and m and n are each 0 or an integer of 1 or more such that m+n=6) and/or a Diels-Alder addition product of said five-membered ring compound (Component A), with 10 to 150 parts by weight of a codimer (Component B) of said five-membered ring compound and 1,3-butadiene; PA0 (b) reacting 100 parts by weight of the resulting hydrocarbon resin (I) with 1 to 15 parts by weight of an unsaturated carboxylic acid or an anhydride thereof (Component C); and PA0 (c) reacting at elevated temperatures 100 parts by weight of the resulting acid-modified resin (II) with 5 to 100 parts by weight of a phenol resin (Component D) obtainable by the condensation of a phenol with formalin.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to varnish compositions for use in offset 
printing inks. 
2. Brief Description of the Prior Art 
As general processes of printing, there have currently been extensively 
used relief printing, lithography (for example, offset printing or the 
like) and photogravure. Of these printing processes, the offset printing 
process comprises transferring inked images from a printing plate roll to 
a rubber blanket and printing the images on paper. The printing plate roll 
is provided with a non-image portion (a water retentive portion) bearing 
water and receiving no oil and an image portion (an inking portion) 
bearing the ink and repelling water. 
Offset printing inks may usually be prepared by adding pigments to resinous 
varnishes comprising resins, solvents, drying oils such as linseed oil, 
and other additives. 
The resinous varnishes for use in offset printing must have the following 
basic properties: 
(1) In order to form images on a flat surface by keeping the ink in contact 
with water, they should maintain a surface balance between the water 
retentive portion and the inking portion; 
(2) they should possess appropriate flowability as indicated by viscosity 
and yield value; 
(3) they should exhibit good dispersibility with pigments; 
(4) they should provide gloss and uniform impressions on the printed 
surface; 
(5) they should quickly set and dry without causing blocking; and 
(6) they should provide printed surfaces having good anti-friction 
property. 
In order to satisfy the above properties required for the resinous 
varnishes for offset printing inks, the resins for use in the varnishes 
must meet the following requirements: 
(1) they should have sufficient solubility in a high boiling point 
hydrocarbon solvent to be used for offset inks which have no aromatic 
content or a low aromatic content; 
(2) they should have sufficient solubility in a drying oil such as linseed 
oil; 
(3) they should have a high softening point, but not a high molecular 
weight; and 
(4) they should have a polar group having pigment dispersibility (a polar 
group having good compatibility with the pigment). 
As varnishes for printing ink, there have currently been used resinous 
varnishes prepared by dissolving a resin such as an alkylphenol resin, a 
rosin-modified phenol or a maleic acid resin in a drying oil such as 
linseed oil. Of these, the rosin-modified phenol resin has been most 
frequently used. A vehicle for printing ink, which comprises the 
rosin-modified phenol resin, a solvent and/or drying oil is excellent in 
quality; however, it has disadvantages in that the supply of rosin is not 
stable and its price is high because it is a naturally occurring 
substance. On the other hand, a so-called petroleum-derived resin which 
may be obtained by polymerizing cracked oil fractions in great quantities 
as by-products in petroleum or petrochemical industry, can offer 
advantages in that it can be constantly supplied and its price is stable; 
however, its quality is not satisfactory. Resins capable of being used as 
resins for printing ink have been little obtained from petroleum-derived 
resins. 
It is disclosed in U.S. Pat. No. 3,084,147 that a resin soluble in a 
hydrocarbon solvent is obtained by thermally polymerizing 
dicyclopentadiene in the presence of an inert hydrocarbon solvent at a 
temperature of 250.degree.-350.degree. C. The dicyclopentadiene resin thus 
obtained cannot be utilized effectively for various uses because of its 
poor compatibility with and adherence to a variety of substances due to 
its lack of polar groups. An ink prepared from this resin by the addition 
thereto of various solvents and pigments is poor in dispersibility with 
the pigments and in its ability to stick to the printing material and 
provide gloss on printed surfaces, and it cannot provide a uniform printed 
surface. Accordingly, it cannot be used as a resin for offset printing 
inks. 
Attempts have been made to provide a resin for use in the preparation of 
printing ink by adding an acrylic acid ester, maleic acid anhydride or the 
like to the above-mentioned dicyclopentadiene resin, hydrolyzing the 
mixture to give a carboxylic acid-containing resin, and then reacting the 
resulting resin with a polyhydric alcohol and a higher unsaturated 
aliphatic acid (Japanese Patent Public Disclosure No. 24,405/1972). An 
offset printing ink prepared from this resin may show decreased 
flowability and gloss on printed surfaces because of decreased solubility 
in petroleum-derived hydrocarbon solvents when the softening point of the 
base resin is elevated to bring its setting and drying times at printing 
to the same values conventional inks exhibit. This resin causes gelation 
and turbidity in the preparation of the varnish and gives an undesirable 
hue to the varnish. In order to improve its solubility in ink solvents, 
the resin must have a lower softening point. Accordingly, its setting and 
drying times become so long that it is no longer practical. 
A resin obtained by thermally copolymerizing cyclopentadiene with maleic 
anhydride is disclosed in U.S. Pat. No. 2,608,550. This resin, when the 
amount of the maleic anhydride is lessened, usually exhibits an 
unfavorable elevation in its softening point and provides poor 
dispersibility with pigments and poor compatibility with other fillers; 
when maleic anhydride is added in larger amounts to improve these 
properties, the resin is apt to cause coloring and gelation, and its 
weather resistance is degraded. 
It is further disclosed in U.S. Pat. No. 2,608,550 that a resin useful for 
ink is prepared by so-called alkyd modification comprising reacting a 
resin prepared by thermal polymerization of dicyclopentadiene with maleic 
anhydride, as a polybasic acid component, with a polyhydric alcohol and a 
drying oil. Since the alkyd resins thus prepared usually have high 
molecular weights, they have poor solubility in a high boiling point 
hydrocarbon solvent and a drying oil for use in ink. Thus, when formulated 
into an ink, the ink exhibits poor flowability and inferior gloss on the 
printed surface. Furthermore, the ink tends to disperse in a mist 
(so-called "misting"), thereby staining the printing paper so that it 
cannot be practically used. 
In every case mentioned hereinabove, those resins are very poor in 
solubility in paraffinic solvents so that they are not applicable 
whatsoever to offset inks where a paraffinic solvent is used. 
In order to provide offset ink compositions which are improved in the 
various properties referred to hereinabove, we have previously proposed 
offset ink compositions containing as vehicles resins obtainable by 
preparing a hydrocarbon resin by copolymerizing a particular five-membered 
ring compound having a conjugated double bond and/or a Diels-Alder 
addition product of the above five-membered ring compound with at least 
one component selected from the group consisting of turpentine oil, 
diisobutylene and nonene; reacting the hydrocarbon resin with an 
unsaturated carboxylic acid or an anhydride thereof to produce an 
acid-modified resin; and then thermally reacting the acid-modified resin 
with a phenol resin obtainable by condensation of a phenol having an alkyl 
group having 4 to 9 carbon atoms with formalin (Japanese Patent 
Application No. 131,665/1978). 
We further proposed novel varnish compositions for use in offset inks, 
containing (a) a resin obtainable by reacting a hydrocarbon resin obtained 
by polymerizing a particular five-membered ring compound having a 
conjugated double bond and/or Diels-Alder addition product thereof with an 
unsaturated carboxylic acid and/or an anhydride thereof to provide an 
acid-modified resin, additionally reacting the resulting acid-modified 
resin with a higher saturated or unsaturated monohydric alcohol having 6 
or more carbon atoms to yield an esterified resin, and then reacting the 
esterified resin with a phenol resin obtainable by reacting a phenol 
having an alkyl substituent having 4 to 9 carbon atoms with formalin; (b) 
a hydrocarbon solvent containing an aromatic content of less than 50% by 
weight and having a boiling point between 200.degree. C. and 350.degree. 
C.; and (c) drying oil (Japanese Patent Application No. 128/1979). 
SUMMARY OF THE INVENTION 
Accordingly, the object of the present invention is to provide varnish 
compositions for use in offset inks, capable of offering the 
above-mentioned various characteristics required for offset inks. 
Another object of the present invention is to provide varnish compositions 
for offset inks, using resins having properties improved over those of 
prior art resins. 
A further object of the present invention is to provide varnish 
compositions for use in offset inks, using resins which are obtainable at 
less cost and in greater quantities from raw materials obtained as 
by-products in the petrochemical industry and which are acceptable 
substitutes for rosin-modified phenol resins. 
DETAILED DESCRIPTION OF THE INVENTION 
The offset ink compositions according to the present invention satisfy the 
above-mentioned objects and have performance identical with or better than 
those of the inventions claimed in the two patent applications referred to 
hereinabove. 
The offset ink compositions according to the present invention contain as a 
vehicle, a resin (III) which is obtained by copolymerizing 100 parts by 
weight of a five-membered ring compound having a conjugated double bond, 
represented by the general formula: 
##STR2## 
(wherein H is hydrogen, R is an alkyl group having 1 to 3 carbon atoms, 
and m and n are each 0 or an integer of 1 or more such that m+n=6) and/or 
a Diels-Alder addition product of the five-membered ring compound 
(Component A), with 10 to 150 parts by weight of a codimer (Component B) 
of the five-membered ring compound and 1,3-butadiene to yield a 
hydrocarbon resin (I); reacting 100 parts by weight of the hydrocarbon 
resin (I) with 1 to 15 parts by weight of an unsaturated carboxylic acid 
or an anhydride thereof (Component C) to yield an acid-modified resin 
(II), and thermally reacting 100 parts by weight of the acid-modified 
resin (II) with 5 to 100 parts by weight of a phenol resin (Component D) 
obtainable by the condensation of a phenol and formalin. 
The compositions according to the present invention will be described below 
in more detail. 
The present invention employs as a raw material component (Component A) a 
five-membered ring compound having a conjugated double bond, represented 
by the following general formula: 
##STR3## 
(wherein H is hydrogen, R is an alkyl group having 1 to 3 carbon atoms, 
and m and n are each 0 or an integer of 1 or more such that m+n=6) or its 
Diels-Alder addition product. 
Specifically, the five-membered ring compounds may include, for example, 
cyclopentadiene and methylcyclopentadiene, and its Diels-Alder addition 
products may include, for example, dicyclopentadiene, 
cyclopentadiene-methylcyclopentadiene codimer and tricyclopentadiene. A 
mixture thereof may be preferably employed on an industrial scale. Among 
these, cyclopentadiene, dicyclopentadiene or a mixture thereof is 
preferred. 
Although a higher purity of Component A is not always necessary, it is 
preferred that cyclopentadiene, dicyclopentadiene or an alkyl-substituted 
derivative thereof be present in the amount of 80% by weight or higher. 
For example, there may be employed a condensed fraction obtainable by the 
removal by distillation of a majority of C.sub.5 components such as 
C.sub.5 olefins, C.sub.5 paraffins or the like from a mixture of 
dicyclopentadiene, dimethylcyclopentadiene, 
cyclopentadiene-methylcyclopentadiene codimer, cyclopentadiene-isoprene 
codimer, cyclopentadiene-piperylene codimer or the like obtainable by the 
thermal dimerization of cyclopentadiene and methylcyclopentadiene 
contained in C.sub.5 fractions produced by high temperature cracking of 
oil by-products such as naphtha. 
It is also possible to employ in Component A a mixture of an unsaturated 
component of petroleum fractions, particularly an unsaturated aromatic 
component, with the five-membered ring compound and/or the Diels-Alder 
addition thereof in an amount equal to or less than the molar amount of 
the latter. For example, styrene, .alpha.-methylstyrene, vinyltoluene, 
indene, methylindene and a mixture thereof may be used. So-called C.sub.9 
fractions by-produced at the time of cracking of naphtha and the like are 
preferred industrially. 
The Component B to be employed in the present invention is a codimer of a 
five-membered ring compound having a conjugated double bond, represented 
by the following general formula: 
##STR4## 
(wherein H is hydrogen, R is an alkyl group having 1 to 3 carbon atoms, 
and m and n are each 0 or an integer of 1 or more such that m+n=6) and 
1,3-butadiene. Specifically, it may include tetrahydroindene, 
vinylnorbornene or a substituted derivative thereof, which are all 
codimers of cyclopentadiene and 1,3-butadiene. A mixture of these may also 
be used. If a dimer of 1,3-butadiene is present in a small amount as a 
by-product in the manufacture of the Component B, the codimer of the 
five-membered ring compound with a conjugated double bond and 
1,3-butadiene, it may also be employed. 
In accordance with the present invention, the hydrocarbon resin (I) may be 
prepared by reacting 10 to 150 parts by weight, preferably 20 to 100 parts 
by weight, of Component B with 100 parts by weight of the above Component 
A in the presence or absence of a catalyst. When the reaction is carried 
out without a catalyst, the hydrocarbon resin (I) may be prepared by 
heating a mixture of the above Components A and B at 200.degree. to 
300.degree. C. for 30 minutes to 15 hours, preferably from 1 to 7 hours. 
On the other hand, a catalyst, including a Friedel-Crafts catalyst, for 
example, boron trifluoride; its complex with phenol, ether, acetic acid or 
the like; or aluminum chloride or the like; may be employed in an amount 
between 0.1 and 10% by weight, and preferably between 0.3 and 2% by weight 
with respect to the total monomer weight. When the reaction is carried out 
in the presence of a catalyst, the reaction conditions may be: a reaction 
temperature from -30.degree. to 100.degree. C., preferably from 0.degree. 
to 50.degree. C., and a reaction time from 10 minutes to 20 hours, 
preferably from 1 to 15 hours. 
In the manufacture of the hydrocarbon resin (I) to be employed in 
accordance with the present invention, when the amount of Component B is 
below the above range, the acid-modified resin (III) resulting from 
modification of this resin has inadequate solubility in paraffinic 
solvents so that it cannot be used for the major purpose of the present 
invention, which is for use in inks for offset printing where a paraffinic 
solvent is employed. When the amount of Component B exceeds the above 
upper limit, the yield of the resin becomes extremely low and the 
softening point of the resin disadvantageously decreases. 
The hydrocarbon resins (I) prepared hereinabove are then reacted with the 
unsaturated carboxylic acid or the anhydride thereof (Component C). The 
Component C is preferably a mono- or poly-unsaturated carboxylic acid or 
an anhydride thereof having generally 3 to 32 carbon atoms, and preferably 
3 to 15 carbon atoms. Representatives are: acrylic acid, methacrylic acid, 
maleic acid, maleic anhydride, tetrahydrophthalic acid and its anhydride, 
fumaric acid, citraconic acid, itaconic acid, mixtures thereof, and fatty 
acids of drying oils, for example a fatty acid of linseed oil or the like. 
Among these, maleic acid and maleic anhydride are preferred. 
The amounts of the unsaturated carboxylic acid or the anhydride thereof to 
be employed in the present invention is 1 to 15 parts by weight, and 
preferably 1 to 10 parts by weight with respect to 100 parts by weight of 
the hydrocarbon resin (I). When the amount of the unsaturated carboxylic 
acid or the anhydride thereof is below the lower limit, it is not 
desirable because of poor characteristics which result fron a low amount 
of polar groups in the formed resin and because of low dispersibility in 
pigments, reduced flowability of ink, and degraded printing effect when 
used as a vehicle for ink. 
When the amount of the unsaturated carboxylic acid or its anhydride exceeds 
the upper limit, it also is not preferred because the amount of the polar 
groups is too high so that the solubility in solvents is decreased, and 
discoloration of the resin and gelation tend to occur. When this is used 
in an ink, it is not preferred because the solubility in a hydrocarbon 
solvent upon varnishing is decreased, and the flowability of ink and gloss 
on the printed surface are lessened. 
The above reaction for modification may be carried out without a catalyst 
or in the presence of a known radical initiator such as an organic 
peroxide or the like at a temperature ranging from 100.degree. to 
300.degree. C., preferably from 150 to 250.degree. C., for 30 minutes to 
15 hours, preferably from 1 to 8 hours. It is preferred to carry out the 
reaction without a catalyst when an unsaturated polycarboxylic acid or the 
anhydride thereof is used, and with a catalyst when an unsaturated 
monocarboxylic acid or the anhydride thereof is used. 
The acid-modified resins to be used in the present invention may also be 
prepared by the following one-step process: In thermally polymerizing a 
mixture of Component A and Component B in the presence or absence of a 
solvent at 200.degree. to 300.degree. C., the unsaturated carboxylic acid 
or the anhydride thereof is added to the reaction system at the beginning 
of or during the reaction and subjected to thermal polymerization. 
In accordance with the present invention, the acid-modified resin (II) may 
be esterified with an alcohol in order to control the solubility and the 
softening point of the acid-modified resin (II) or to regulate the 
molecular weight of the resin (III). The alcohol to be used in this case 
may include a mono- or poly-hydric alcohol. When a monohydric alcohol 
having 6 or more carbon atoms, and preferably from 8 to 18 carbon atoms, 
is employed, the particularly preferred solubility of the modified resin 
(III) may be achieved. The amount of the alcohol may be from 0 to 1.0 
molar equivalent with respect to the equimolar equivalent of the carboxyl 
groups in the acid-modified resin (II) or from 0 to 2.0 molar equivalents 
with respect to the equimolar equivalent of the acid anhydride groups in 
the resin (II). The esterification may be effected by heat-melting the 
acid-modified resin and then adding the alcohol, or by dissolving the 
acid-modified resin in a hydrocarbon solvent such as benzene, toluene, 
xylene or the like and adding the alcohol. The reaction may be carried out 
for 30 minutes to 10 hours, and preferably from 1 to 5 hours, at a 
temperature of 150.degree. to 250.degree. C. 
In accordance with the present invention, the acid-modified resin (II) is 
further reacted with the phenol resin (Component D) to provide the desired 
modified resin (III). The phenol resin to be employed in the present 
invention is preferably one which may be prepared by condensation of a 
phenol having an alkyl substituent wih 4 to 9 carbon atoms and formalin, 
and may include specifically p-tert-butylphenol, sec-butylphenol, 
p-tert-octylphenol, nonylphenol or the like, which is preferable for 
industrial use. 
Instead of the reaction with the phenol resin, the desired phenol resin 
modified resins may be prepared by reacting formaldehyde and a phenol in 
the presence of the acid-modified resin (II) and in the presence or 
absence of a catalyst such as oxalic acid, maleic acid or the like. 
The amount of the phenol resin to be used for modification may range from 5 
to 100 parts by weight, preferably from 10 to 50 parts by weight, of the 
phenol resin with respect to 100 parts by weight of the acid-modified 
resin (II). When the amount of the phenol resin is below the stated lower 
limit, an ink using this modified resin as a vehicle cannot provide 
sufficient flowability or an appropriate gloss on printed surfaces. When 
the amount of the phenol resin exceeds the stated upper limit, it is not 
preferred because the solubility of the resin in an ink solvent is 
decreased; it is not industrially desirable and it is not economical. 
This reaction proceeds merely by melting a mixture of the acid-modified 
resin (II) and the phenol resin at 150.degree. to 250.degree. C. for 30 
minutes to 10 hours, preferably from 1 to 5 hours. If necessary, an acid 
catalyst such as oxalic acid, toluenesulfonic acid, a Friedel-Crafts 
catalyst or the like may be employed. 
The resin (III) as prepared hereinabove preferably has a softening point of 
100.degree. C. or higher, more preferably 130.degree. C. or higher. When 
the softening point is lower than 100.degree. C., it is not desirable 
because, when used in an ink for printing, the phenomenon of misting tends 
to occur frequently, the time required for drying is extremely prolonged, 
and blocking tends to occur. 
The resin (III) preferably has an acid value of 5 to 50, and more 
preferably 5 to 20. Where the acid value is below the lower value, the ink 
resulting therefrom has poor flowability. A resin having an acid value 
above the upper limit has lessened solubility in paraffinic solvents and, 
when included in an ink for offset printing, the inks resistance to 
emulsion is so degraded that it is not desirable. 
The resin (III) as prepared hereinabove may be employed as a vehicle to 
prepare an offset ink composition in accordance with the present invention 
by usual, known and arbitrary methods. The ink composition in accordance 
with the present invention may be prepared by dissolving 100 parts by 
weight of the resin (III) in 50 to 200 parts by weight of a high boiling 
point paraffinic solvent and 0 to 150 parts by weight, preferably from 5 
to 30 parts by weight, of a drying oil at ambient or elevated temperatures 
to provide a varnish adjusted to have a viscosity between 200 and 600 
poises at ordinary temperature; formulating a pigment or the like 
therewith; and mixing and kneading by means of a roll mixer or the like. 
The high boiling point paraffinic solvent to be used in the present 
invention may be one having a boiling point between 200.degree. and 
350.degree. C. and having substantially no aromatic component, although 
usual high boiling point hydrocarbon solvents having an aromatic component 
of 50% or less may be used. The oil component such as the drying oil or 
the like may also include a long oil type alkyd resin as well as linseed 
oil, tung oil or the like.

The following examples illustrate specifically the present invention, but 
should only be construed as illustrating a few examples. Accordingly, the 
present invention is not restricted to the examples as long as it does not 
deviate from the spirit and scope of the present invention. 
SYNTHESIS EXAMPLE 1 
Dicyclopentadiene (DCPD) of 97% purity (580 grams), 350 grams of 
tetrahydroindene (THI) and 70 grams of methyltetrahydroindene (MeTHI) were 
charged into a 2 liter autoclave, and the mixture was heated and stirred 
at 260.degree. C. for 5 hours in a nitrogen atmosphere. After completion 
of the reaction, the autoclave was cooled and subjected to distillation at 
a temperature of 210.degree. C. and a pressure of 2 mmHg to distill off 
the unreacted and low molecular weight materials, thereby leaving as a 
residual material 810 grams of a hydrocarbon resin (I-1). This resin had a 
softening point of 150.0.degree. C. 
This hydrocarbon resin (I-1) (100 grams) was heat-melted at 200.degree. C. 
and, after the addition thereto of 3.0 grams of maleic acid anhydride, 
stirred for 4 hours to provide an acid-modified resin (II-1) having a 
softening point of 161.0.degree. C. and an acid value of 13.0. The 
acid-modified resin (II-1) (103.0 grams) was then mixed with 18.2 grams of 
a resol type phenol resin obtainable by the condensation reaction of 
p-tert-octylphenol and formalin, and the mixture was heated at 195.degree. 
C. for 2 hours to provide a modified resin (III-1) having a softening 
point of 180.0.degree. C. and an acid value of 12.0. 
SYNTHESIS EXAMPLE 2 
DCPD of 97% purity (500 grams), 400 grams of vinylnorbornene (VNB) and 100 
grams of vinylcyclohexene (VCH) were charged into a 2 liter autoclave, 
subjected to reaction at 260.degree. C. for 4 hours, and treated in the 
same manner as in Synthesis Example 1 to provide 750 grams of a 
hydrocarbon resin (I-2) having a softening point of 143.0.degree. C. 
The hydrocarbon resin (I-2) (100 grams) was heat-melted at 200.degree. C. 
and, after the addition of 4.0 grams of maleic anhydride, stirred for 3 
hours to provide an acid-modified resin (II-2) having a softening point of 
158.0.degree. C. and an acid value of 18. The acid-modified resin (II-2) 
(104.0 grams) was then mixed with 18.4 grams of a resol type phenol resin 
prepared by the condensation reaction of p-tert-butylphenol and formalin, 
and the mixture was then reacted at 190.degree. C. for 3 hours to provide 
a modified resin (II-2) having a softening point of 175.0.degree. C. and 
an acid value of 15.0. 
SYNTHESIS EXAMPLE 3 
DCPD of 97% purity (450 grams), 300 grams of THI, 150 grams of VNB and 100 
grams of MeTHI were charged into a 2 liter autoclave, reacted at 
270.degree. C. for 3 hours, and then treated in the same manner as in 
Synthesis Example 1 to provide 730 grams of a hydrocarbon resin (I-3) 
having a softening point of 145.0.degree. C. 
The hydrocarbon resin (I-3) (100 grams) was heat-melted at 200.degree. C. 
and, after the addition thereto of 5.0 grams of maleic anhydride, stirred 
for 3 hours to provide an acid-modified resin (II-3) having a softening 
point of 160.0.degree. C. and an acid value of 22.0. The acid-modified 
resin (II-3) (105.0 grams) was stirred at 180.degree. C. for 1 hour after 
the addition of 4.0 grams of decanol and then reacted with 16.3 grams of a 
resol type phenol resin prepared by the condensation of p-nonylphenol and 
formalin, thereby providing a modified resin (III-3) having softening 
point of 165.0.degree. C. and an acid value of 19.0. 
SYNTHESIS EXAMPLE 4 
DCPD of 97% purity (600 grams) and 400 grams of THI were charged into a 2 
liter autoclave, reacted at 260.degree. C. for 6 hours, and then treated 
in the same manner as in Synthesis Example 1 to provide 800 grams of a 
hydrocarbon resin (I-4) having a softening point of 151.0.degree. C. 
The hydrocarbon resin (I-4) (100 grams) was then heat-melted at 200.degree. 
C. and, after the addition of 4.0 grams of maleic anhydride, stirred for 3 
hours to provide an acid-modified resin (II-4) having a softening point of 
162.0.degree. C. and an acid value of 17.0. Then, 104.0 grams of the 
acid-modified resin (II-4) were mixed with 22.9 grams of a resol type 
phenol resin prepared by the condensation of p-tert-butylphenol and 
formalin, and the mixture was reacted at 190.degree. C. for 2 hours to 
provide a modified resin (III-4) having a softening point of 178.0.degree. 
C. and an acid value of 15.0. 
SYNTHESIS EXAMPLE 5 
C.sub.5 cracked oil fractions (boiling points, 28.degree.-60.degree. C.), 
prepared as by-products in the manufacture of ethylene, propylene or the 
like by the steam cracking of naphtha were subjected to distillation at 
120.degree. C. for 4 hours to remove the C.sub.5 fractions, thereby 
leaving a residual material containing 85% DCPD and, as other components, 
codimers of cyclopentadiene with isoprene or piperylene. Then 650 grams of 
the fractions containing 85% DCPD and 450 grams of VNB were charged into a 
2 liter autoclave, reacted at 270.degree. C. for 3 hours, and then treated 
in the same manner as in Synthesis Example 1 to produce 850 grams of a 
hydrocarbon resin (I-5) having a softening point of 155.0.degree. C. Then 
100 grams of the hydrocarbon resin (I-5) were heat-melted at 200.degree. 
C., mixed with 4.0 grams maleic acid anhydride, and stirred for 4 hours to 
provide an acid-modified resin (II-5) having a softening point of 
165.0.degree. C. and an acid value of 18.0. The acid-modified resin (104.0 
grams) was then mixed with 3.5 grams of 2-ethylhexanol and stirred at 
180.degree. C. for 1 hour, followed by the addition thereto of 17.0 grams 
of a resol type phenol resin prepared by the condensation of 
p-tert-octylphenol and formalin. The mixture was reacted at 190.degree. C. 
for 3 hours, thereby providing a modified resin (III-5) having a softening 
point of 175.0.degree. C. and an acid value of 15.0. 
COMATIVE SYNTHESIS EXAMPLE 1 
DCPD of 95% purity (1,000 grams) and 400 grams of xylene as a solvent were 
charged into a 2 liter autoclave, reacted at 260.degree. C. for 3 hours, 
and treated in the same manner as in Synthesis Example 1 to provide 800 
grams of a hydrocarbon resin (I-a) having a softening point of 
152.0.degree. C. 
The hydrocarbon resin (I-a) (100 grams) was heat-melted at 200.degree. C., 
mixed with 3.0 grams of maleic anhydride, and treated for 4 hours to 
provide an acid-modified resin (II-a) having a softening point of 
162.0.degree. C. and an acid value of 13.0. The acid-modified resin (II-a) 
(103.0 grams) was then mixed with 18.2 grams of a resol type phenol resin 
prepared by the condensation of p-tert-octylphenol and formalin and 
reacted at 195.degree. C. for 2 hours, thereby producing a resin (III-a) 
having a softening point of 178.0.degree. C. and an acid value of 12.0. 
COMATIVE SYNTHESIS EXAMPLE 2 
The hydrocarbon resin (I-1) (100 grams) obtained in Synthesis Example 1 was 
heat-melted at 190.degree. C., mixed with 15.0 grams of a resol type 
phenol resin prepared by the condensation of p-tert-octylphenol and 
formalin, then reacted with stirring at 190.degree. C. for 2 hours to 
provide a resin (III-b) having a softening point of 155.0.degree. C. and 
an acid value of 0. 
EXAMPLES 1-5 AND COMATIVE EXAMPLES 1-4 
The modified resins obtained in the above Synthesis Examples 1-5, 
Comparative Synthesis Examples 1 and 2, the acid-modified resin (II-1) 
obtained in Synthesis Example 1, and a control resin, respectively, were 
formulated as described below to prepare a varnish. Each of the varnishes 
so prepared was then included in an ink which was tested for ink 
performance. The test results are shown in the table below as Examples 1-5 
and Comparative Examples 1-4, respectively. 
(PREATION OF VARNISHES) 
A mixture of 50 grams of the product resin, 10 grams of linseed oil and 
20-40 grams of a high boiling point paraffinic solvent (NISSEKI No. 0 
Solvent H: product of Nippon Oil Company Ltd., boiling point, 
250.degree.-265.degree. C.; a pure aliphatic hydrocarbon solvent 
containing no aromatic components) was heat-melted at 180.degree. C. to 
provide a varnish having a viscosity of 300 to 400 poises. 
(PREATION OF INKS) 
An ink was formulated by mixing the following by means of three rolls. 
______________________________________ 
Pigment (trademark "Karmin 6B: product 
of Toyo Ink Seizo K.K.) 14 grams 
Varnish 50 grams 
Solvent (Nisseki No. 0 Solvent H) 
15 grams 
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(PERFORMANCE TEST METHOD AND RESULTS) 
Gloss: 0.4 cc of the ink was applied to a coated paper by means of an RI 
tester (manufactured by Akira Seisakusho K.K.), dried for 10 seconds in an 
oven at 150.degree. C., and then measured with a 60.degree.--60.degree. 
glossmeter. 
Drying Time: 0.4 cc of the ink was applied to a parchment paper with said 
RI tester, placed in an oven heated to 150.degree. C. and measured for the 
time required to lose stickness perceivable by finger touch. 
Misting: 2.4 cc of the ink was placed on an incometer (manufactured by Toyo 
Seiki K.K.), rotated at 1,200 r.p.m. for 3 minutes, and measured for the 
degree of scattering on a coated paper placed under the roll. 
Emulsification characteristics of ink: Water was added to the adjusted ink 
to emulsify the ink, and the ink was measured for its flowability. An ink 
for offset printing is not practical if the emulsified ink does not have 
good flowability because the ink is brought into contact with water during 
printing and is partially emulsified. 
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Viscosity 
of Varnish 
Physical 
Gloss on 
Drying Emulsification 
Type of (poises 
Appearance 
Printed 
Period Characteristics 
Resins 25.degree. C.) 
of Varnish 
Surface 
(sec) 
Misting 
of Ink 
__________________________________________________________________________ 
Example 1 
III - 1 
410 Transparent 
65 5 Did not 
Favorable 
(Synthesis occur 
Example 1) 
Example 2 
III - 2 
350 Transparent 
68 6 Did not 
Favorable 
(Synthesis occur 
Example 2) 
Example 3 
III - 3 
330 Transparent 
70 8 Did not 
Favorable 
(Synthesis occur 
Example 3) 
Example 4 
III - 4 
370 Transparent 
68 6 Did not 
Favorable 
(Synthesis occur 
Example 4) 
Example 5 
III - 5 
360 Transparent 
70 7 Did not 
Favorable 
(Synthesis occur 
Example 5) 
Compara- 
III - a 
No ink was prepared because a transparent varnish was not 
tive (Comparative 
obtained due to poor solubility of the resin in paraffinic 
Example 1 
Synthesis 
solvents. 
Example 1) 
Compara- 
III - b 
250 Turbid 55 20 Occurred 
Not Good 
tive (Comparative Bad hue 
Example 2 
Synthesis 
Example 2) 
Compara- 
II - 1 180 Turbid 40 15 Occurred 
Not Good 
tive (Synthesis 
Example 3 
Example 1) 
Compara- 
(Control 
370 Transparent 
66 7 Did not 
Slightly 
tive Resin* Occur 
inferior 
Example 4 
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*Rosin-modified phenol resin (Trademark Tamanol 361: Arakawa Kagaku K.K.) 
As shown in Examples 1 to 5 according to the present invention, it is 
apparent that the offset ink compositions in accordance with the present 
invention have excellent gloss and emulsification characteristics, and 
favorable misting and drying performance when a paraffinic solvent is 
used. 
It is shown from Comparative Example 1 that a uniform ink cannot be 
obtained with a resin containing no codimer of cyclopentadiene and 
1,3-butadiene because of poor solubility. 
Comparative Example 2 represents an example in which the resin is not 
acid-modified during the step of modification. This resin cannot provide a 
complete reaction with the phenol resin. Thus, it produces no resin having 
a high softening point, and an ink prepared therefrom was poor in both 
drying and emulsifying characteristics. 
It is shown from Comparative Example 3, which represents an example in 
which no modification with a phenol resin is effected, that such a resin 
is not practically applicable because of its poor gloss, and drying and 
emulsifying characteristics. 
As a control, an ink was prepared by using a rosin-modified phenol resin 
having excellent solubility in paraffinic solvents. This was compared with 
the examples according to the present invention. As a result, it is shown 
that the offset ink composition according to the present invention are 
superior in emulsification performance to the ink prepared from the 
rosin-modified phenol resin.