Non-dimer acidic polyamide from medium chain diacid having improved water solubility useful as flexographic/gravure ink binder

Polyamide resins useful as binders in flexographic/gravure inks are provided which are essentially free of polyeric fat acids. These polyamide resins exhibit improved water solubility, yet still retain the other many desirable properties of polyamide resins based on polymeric fat acids. The resins are acid terminated having acid values greater than 30 and are prepared from medium chain (12-26 carbons) dicarboxylic acids such as the C.sub.21 acid, 2-n-hexyl-5-(7-carboxyl-n-heptyl)-cyclohex-3-ene carboxylic acid, and aliphatic diamines having from 2-12 carbon atoms.

This invention relates to polyamide resins having improved water solubility 
which are useful as flexographic/gravure ink binders. More particularly, 
this invention relates to polyamide resins which are essentially free of 
dimeric and higher polymeric fat acids. 
BACKGROUND OF THE INVENTION 
U.S. Pat. No. 3,776,865 to Glaser and Lovald discloses polyamide resins 
obtained by reacting an acid component comprised of a polymeric fat acid 
and another dicarboxylic acid with an amine component comprising 
isophorone diamine or mixtures thereof with an alkylene diamine. At least 
12.5 carboxyl equivalent percent of the polymeric fat acid is employed. 
The patentees disclose that these resins are useful as binders applied by 
aqueous systems, particularly in flexographic/gravure inks where water 
reducibility is desired. 
U.S. Pat. No. 4,051,087 to Scoggins et al describes copolyamide resins 
useful as hot melt adhesives, molding resins, coatings or films. These are 
achieved through the use of substantially requivalent amounts of carboxyl 
and amine, i.e. a 1:1 ratio, proving essentially neutral resins. Only a 
slight excess, up to 5 mol percent of carboxyl or amine may be present. 
Examples I, II, III and V employed a polymeric (dimeric) fat acid, while 
Example IV employed azelaic acid in the absence of the dimer acid. The 
Example IV product is indicated as inferior to the polyamide employing the 
dimeric fat acid. 
U.S. Pat. No. 3,781,234 to Drawert et al is another patent describing 
polymeric fat acids polyamides useful as hot melt adhesives. Approximately 
stoichiometric amounts of amine (ethylene diamine) and a carboxyl are 
employed, providing essentially neutral polyamides, neither acid value or 
amine value substantially exceeding the other. A copolymerizing C.sub.19 
acid, heptadecane dicarboxylic acid is required along with the dimerized 
fatty acid. 
U.S. Pat. No. 4,055,525 to Cheng describes a polyamide again useful as a 
hot melt adhesive. Substantially equivalent amounts of amine 
(hexamethylene diamine) and carboxyl are employed, so that a neutral 
polymer is provided. The acid component is comprised of a C.sub.19 diacid 
in admixture with another aliphatic dicarboxylic acid containing 5-10 
carbon atoms. 
Polyamide resins prepared from dimeric and/or higher polymeric fatty acids 
for use in flexographic/gravure inks are dissolved in volatile organic 
solvents, such as the lower alkanols. Environmental concern over the 
amounts of volatile organic solvents in the atmosphere has led to a desire 
to use aqueous solutions that have less volatile organic solvents 
contained therein. In order to accommodate the reduced levels of volatile 
organic solvents, the polyamide resins used as binders in 
flexographic/gravure inks should have increased water solubility and yet 
retain the other desirable properties of polyamide resins, based on 
polymeric fat acids. 
SUMMARY OF THE INVENTION 
The present invention provides polyamide resins which are acid terminated, 
i.e. an equivalent excess of acid is used in relation to the diamine so as 
to provide an acid value greater than 30. The resins ideally contain no 
polymeric fat acid (dimeric fat acid), although a small amount, up to 5 
carboxyl equivalent percent may be tolerated without unduly sacrificing 
the advantageous properties of the products of the present invention, 
particularly as a binder for inks having increased water solubility. The 
polyamide resins are prepared from a mixture of a medium chain (12-26 
carbon) dicarboxylic acid and a short chain (2-10) carbon dicarboxylic 
acid. A short chain (2-6 carbon) monocarboxylic acid may be employed 
primarily as a chain stopper; however, its presence is not necessary and 
may be omitted. The acids are reacted with a diamine having from 2-12 
carbon atoms. 
In its broadest scope, the present invention relates to polyamide resin 
compositions obtained by the reaction of an acid component comprised of a 
medium chain dicarboxylic acid having from 12-26 carbon atoms and an amine 
component comprised of an aliphatic diamine containing from 2-12 carbon 
atoms wherein the amine equivalent of the diamine employed is less than 
the carboxyl equivalents of the acid component so as to provide an acid 
value of the resin greater than 30 and the acid value exceeds the amine 
value by at least 20 units. 
When the acid component contains a copolymerizing short chain dicarboxylic 
acid, the products of the present invention may be described as polyamide 
resin compositions formed from, or obtained by, the amidification or 
condensation reaction of 
(A) An acid component comprising 
(1) about X equivalent percent of a medium-chain dicarboxylic acid having 
from 12 to 26 aliphatic carbon atoms; 
(2) about Y equivalent percent of a short-chain acyclic aliphatic 
dicarboxylic acid having from 2 to 10 aliphatic carbon atoms; and 
(B) an amine component comprising about Z equivalent percent of a diamine 
having from 2 to 12 aliphatic carbon atoms or mixtures thereof; wherein 
the ratio of Z to the sum of X and Y is less than 1, so as to provide an 
acid value greater than 30. 
The preferred polyamides are those wherein the ratio of Z to the sum of X 
and Y is less than about 0.9, more preferably ranges from about 0.50 to 
about 0.85, and most preferably from about 0.65 to about 0.85. 
Where a monocarboxylic acid is employed in the acid component, the acid 
component can be defined as being a mixture of: 
(a) about X equivalent percent of a medium chain dicarboxylic acid having 
from 12-26 aliphatic carbon atoms; 
(b) about Y equivalent percent of a short chain acyclic aliphatic 
dicarboxylic acid having from 2-10 aliphatic carbon atoms and 
(c) about Y' equivalent percent of a short chain aliphatic monocarboxylic 
acid having from 3-5 aliphatic carbon atoms. 
In such case, the ratio of Z to the sum of X, Y and Y' is less than 1. As 
is apparent in a situation where no monocarboxylic acid is employed, Y' 
would be zero. 
The invention also provides binder compositions flexographic/gravure ink 
compositions containing such resins. 
It has been found that the polyamide resins of this invention are more 
soluble in flexographic/gravure ink compositions containing more water and 
less volatile organic solvent than flexographic/gravure ink compositions 
containing polyamide resins based on polymeric fat acids. In spite of this 
increased water solubility, however, the polyamide resins yield ink 
coatings with acceptable water-resistance and other desirable properties. 
DETAILED DESCRIPTION OF THE INVENTION 
The polyamide resins of the present invention are prepared by reacting or 
polymerizing a mixture of an acid component which contains at least two 
different carboxylic acids with an amine component containing at least one 
diamine. These resins are acid terminated resins in that an equivalent 
excess of the dicarboxylic acids are used in relation to the diamine, so 
as to provide an acid value of greater than 30. Using such excess, the 
amine value will be low and the acid value will exceed the amine value by 
at least 20. Thus, the amine value will be 10 or lower. A monobasic acid 
can also be used in the acid component as a chain stopper. In achieving 
the acid value of at least 30, the ratio of amine equivalents of the 
diamines to the carboxyl equivalents of the acids is therefore less than 
1, preferably less than about 0.9, more preferably ranges from 0.50 to 
about 0.85, and most preferably about 0.65 to 0.85. 
The polyamides of the present invention may be defined as a polymer or 
resin obtained by the reaction of: 
(A) an acid component comprising a mixture of 
(1) about X carboxyl equivalent percent of a medium chain aliphatic 
dicarboxylic acid having from 12-26 carbon atoms; 
(2) about Y carboxyl equivalent percent of a short chain alicyclic 
aliphatic dicarboxylic acid having from 2-8 carbon atoms; and 
(B) an amine component comprising Z amine equivalent percent of an 
aliphatic diamine containing 2-12 carbon atoms. 
wherein the equivalent ratio of Z to the sum of X and Y is less than 1 so 
as to provide an acid value greater than 30. With such acid values, the 
acid value will exceed the amine value by about 20. 
When a monocarboxylic acid is employed, the acid component will comprise a 
mixture of: 
(1) X carboxyl equivalent percent of the medium aliphatic dicarboxylic acid 
defined above; 
(2) Y carboxyl equivalent percent of the short chain dicarboxylic acid 
defined above; and 
(3) Y' carboxyl equivalent percent of a short chain aliphatic 
monocarboxylic acid having from 2-6 carbon atoms. 
With an acid component as above, the ratio of Z to the sum of X, Y and Y' 
is less than 1 so as to provide an acid value greater than 30. 
The carboxylic acid useful in the present invention accordingly can be 
divided into two groups on the basis of chain length. The acids of one 
group have medium-chain length and the acids of the other group have 
short-chain length. The medium-chain aliphatic dicarboxylic acids are 
present in all of the polyamide resins of this invention. The other group 
of acids, i.e. the short-chain carboxylic acid used to prepare the 
polyamide resins of this invention, can be further subdivided into two 
groups on the basis of functionality. In general, it is preferred that the 
short-chain acyclic dicarboxylic acids be used to the exclusion of the 
short-chain aliphatic monocarboxylic acids (in which case the amount Y' is 
zero), especially when the diamine chosen is isophorone diamine, and that 
the short-chain aliphatic monocarboxylic acids be used to the exclusion of 
the short-chain acyclic aliphatic dicarboxylic acids (in which case the 
amount Y is zero), especially when the diamine chosen is ethylene diamine. 
The medium-chain aliphatic dicarboxylic acids (hereinafter referred to as 
the medium-chain diacids) necessary in this invention have from 12 to 26 
carbon atoms, preferably from 16 to 22. This class of dicarboxylic acids 
includes not only the homologous series beginning with dodecanedioic acid 
and extending to the 24 carbon diacid, but also includes dicarboxylic 
acids that have branched alkyl chains and alicyclic structures in the 
molecule as well. 
These medium chain dicarboxylic acids may be represented by the formula 
EQU HOOC--R.sub.1 --COOH 
where R is a divalent aliphatic hydrocarbon radical containing from 10 to 
24 carbon atoms, straight or branched chain, acyclic or alicyclic. 
Preferably, R contains 14 to 20 carbon atoms. 
A preferred class of medium-chain diacids are those having a carboxylic 
ring and three substituents wherein one substituent is a carboxyl group, a 
second substituent is an alkyl group having more than three aliphatic 
carbon atoms, and a third substituent is an alkyl group that is terminally 
substituted with a carboxyl group. Examples of the medium-chain diacid of 
this preferred class may be obtained as the Diels Alder reaction products 
of acrylic acid with a fatty acid having two conjugated ethylenic 
unsaturations. A preferred example of the medium-chain diacids is 
2-n-hexyl-5-(7-carboxylic-n-heptyl)-cyclohex-3-ene carboxylic acid which 
is a C.sub.21 acid available from Westvaco, Charleston Heights, S.C., as 
Westvaco DiAcid. 
The short-chain acyclic aliphatic dicarboxylic acids (hereinafter referred 
to as short-chain diacids useful in this invention) have from 2 to 10 
carbon atoms in a unbranched hydrocarbon chain. The short-chain diacids 
can be characterized as a homologous series of dicarboxylic acids which 
begins with oxalic acid, ends with decanedioic acid, and includes each 
member in-between. The short chain diacids may also be represented by the 
formula 
EQU HOOC--(R.sub.2).sub.n --COOH 
where R.sub.2 is defined as a divalent, straight chain alkylene radical 
having 2-8 carbon atoms and n is 0 or 1. When n is 0, the acid is oxalic 
acid, HOOCCOOH. When n is 1, the acids include the dicarboxylic acids from 
propanedioic (malonic) to decanedioic (sebacic). The preferred short-chain 
diacids are azelaic acid and adipic acid. 
The amounts of short-chain diacid and medium-chain diacid used in the 
polyamides of this invention are preferably chosen such that the ratio of 
equivalents of the short-chain diacid to equivalents of the medium-chain 
diacid range from about 4:1 to about 0.66:1, more preferably from about 
3:1 to about 0.8:1, and most preferably from about 1:1 to 2:1. 
The short-chain aliphatic monocarboxylic acids (hereinafter referred to as 
short-chain monoacid) useful in this invention have from 2 to 6 carbon 
atoms. These monocarboxylic acids may be represented by the formula 
EQU R.sub.3 --COOH 
where R.sub.3 is a straight or branched chain alkyl group containing from 
1-5 carbon atoms. The short chain acids are exemplified by acetic, 
propionic acid, n-butanoic acid, isobutanoic acid, and the like. The 
preferred short-chain acid is propionic acid. 
The amounts of the medium-chain diacid and short-chain monoacid used in the 
polyamides of this invention are preferably chosen such that the ratio of 
equivalents of the medium-chain diacid to the equivalents of the 
short-chain monoacid ratio of about 1:1 to about 5:1, more preferably from 
about 2:1 to about 4:1, and most preferably about 3:1. 
The acid component of the present invention will accordingly be composed as 
follows: 
______________________________________ 
Acid Component - 100 Equivalents 
Eq. % 
______________________________________ 
Medium Chain Dicarboxylic Acid 
20-100 
Short Chain Dicarboxylic Acid 
0-80 
Short Chain Monobasic Acid 
0-35 
Carboxyl Equivalent Percent 
100 
______________________________________ 
The polyamides of this invention are prepared from mixtures that are 
substantially free of polymeric fat acids. These polymeric fat acids, 
which can be characterized as long-chain polybasic acids, are described in 
U.S. Pat. No. 3,776,865. These polymeric fat acids are derived by 
polymerizing either saturated or unsaturated fatty acids. It has been 
found that the amount of polymeric fat acid used in the polyamides of this 
invention should be minimized to obtain improved water solubility in the 
polyamide resin. The mixtures from which the resins of this invention are 
prepared are substantially free of polymeric fat acids, i.e. they may 
contain an amount of a polymeric fat acid equal to as much as 5 equivalent 
percent of the polyamide reaction mixture but preferably less than 5 
equivalent percent and most preferably zero equivalent percent. With 
amounts of about 10 equivalent percent, i.e. 12.5 equivalent percent of a 
polymeric fat acid, the properties are adversely affected to the point 
where the products are insoluble or gelled and unsuitable for use in 
flexographic inks. 
The diamine used to form the polyamide resins of this invention is 
comprised of at least one aliphatic diamine having from 2 to 12 aliphatic 
carbon atoms. The preferred diamines can be divided into two preferred 
groups. One group consists of cyclic aliphatic diamines having from 8-12 
aliphatic carbon atoms, e.g. isophorone diamine. The other preferred group 
is comprised of short-chain alkylene diamines which can be represented by 
the formula: 
EQU H.sub.2 N--R--NH.sub.2 
wherein R is an alkylene radical having from 2 to 8 carbon atoms. R may be 
branched or straight chained, the straight chain radicals being preferred. 
Specific examples of short-chain alkylene diamines are ethylene diamine, 
diamino-propane, diamino-butane, and hexamethylene diamine. 
The polyamide resins of this invention will contain the structural unit 
##STR1## 
where R and R.sub.2 are as earlier defined. Where a short chain 
dicarboxylic acid is also employed, the resin will also contain the 
structural unit 
##STR2## 
The short chain monocarboxylic acid is employed as a chain stopper which, 
along wih the acid and amine ratios employed, will control the degree of 
polymerization of the mixture, the number of recurring structural units, 
and the amine and acid numbers. 
The resins are prepared from mixtures contaning a dicarboxylic acid 
component and a diamine component by known methods for the polymerization 
of diacids and diamine to form polyamides. In general, a mixture of the 
diacid component and the diamine component is heated to a temperature 
between about 100.degree. C. and 250.degree. C. in a vessel equipped for 
the removal of the by-product water formed in the polyamidification 
reaction; e.g. a vessel fitted with a distillation column and condenser so 
as to remove water from the reaction zone. 
Typically the reaction mixture will be heated at lower temperatures 
initially to avoid any volatilization and loss of any short chain monoacid 
which may be employed, after which the temperature is raised to the higher 
reaction temperature. Thus, it is common to heat at about 140.degree. C. 
for about 1 hour followed by raising the temperature to about 250.degree. 
C. and reacting for about 1.5-3 hours. 
Similarly, a portion of the charge of the medium-chain diacid can be 
reserved from the initial charge of reactants. The initial reactant 
mixture can be initially reacted to ensure that substantially all of the 
short-chain monoacid is incorporated into the resin. The reserved portion 
of medium-chain diacid is then charged and the resulting mixture is 
allowed to react to obtain an acid terminated product. For example, from 
about 25% to about 50% of the medium-chain diacid to be charged is 
reserved from the initial charge which is heated at about 140.degree. C. 
for one hour. The reserved portion of medium-chain diacid is then added to 
the reaction mixture and the temperature is raised to about 250.degree. C. 
for about 11/2 to 3 hours to obtain a product having acid termination. 
The degree of polymerization of the mixture should be controlled, along 
with the choice of ratio of diamine to diacids, to obtain a polyamide 
having a high acid value (greater than 30). The acid value of the 
polyamide preferably should be greater than about 50, Generally, the 
products will have an acid value between 30 up to about 100. With such 
acid values, the amine numbers will be low, less than about 10, 
approaching a value of about 1-5. Thus, the acid number will exceed the 
amine value by about 20, and generally higher. 
The polyamide resins of this invention form the binder compositions of this 
invention when dissolved in an aqueous solvent containing an organic 
amine. The resin is added to the solvent in an amount of about 30% to 
about 40% resin solids based on the weight of the solvent. Examples of 
suitable organic amines include primary, secondary and tertiary amines 
which can act as a base to salt the acid terminated polyamides. 
Particularly preferred organic amines are the dialkylaminoalkanols, such 
as 2-(N,N-dimethylamino)ethanol and 2-(N,N-diethylamino)ethanol. 
The organic amine is present in the aqueous solution in an amount 
sufficient to solubilize the chosen polyamide resin. In general, the 
organic amine will be present in the aqueous solution in an amount 
sufficient to theoretically neutralize the acid groups of the polyamide, 
i.e. the amount of organic amine is stoichiometrically equivalent to or 
greater than the acid value of the polyamide. For example, a 7.4% solution 
of dimethylaminoethanol is stoichiometrically equivalent to a polyamide 
resin having an acid value of about 70 used at the level of 40% resin 
solids. A large excess of organic amine should be avoided because 
retention of the organic amine in the cured binder may adversely affect 
the water retention of the binder. 
These binders are particularly useful in flexographic/gravure ink 
compositions. 
The flexographic/gravure ink compositions of this invention are preferably 
made by dispersing a flexographic/gravure ink pigment in the binder 
compositions of this invention. 
It is an advantage of the present invention that less volatile organic 
solvent is needed to solubilize the resin in the binder compositions used 
to make flexographic/gravure ink compositions of this invention than is 
needed to solubilize the dimer acid resins of U.S. Pat. No. 3,776,865. 
Generally, the flexographic/gravure ink compositions of this invention can 
contain less than about 25% by volume volatile organic solvent. The 
preferred resins can be used to prepare binders which contain even less 
volatile organic solvent, e.g. 5% to 20%, but which still yield 
flexographic/gravure ink coatings having good water resistance.

EXAMPLES 
The following Examples show the preparation and properties of polyamide 
resins representative of the polyamide resins of this invention and the 
preparation and properties of comparative polyamide resins. The polyamide 
resins of this invention are denoted by an arabic numeral and the 
comparative polyamide resins are denoted by a letter. 
Definitions 
In the following Examples, the following terms, abbreviations and symbols 
have the following meanings: 
MCD: 2-n-hexyl-5-(7-carboxyl-n-heptyl)-cyclohex-3-ene carboxylic acid, 
available from Westvaco as Westvaco DiAcid. 
ADA: adipic acid 
AZA: azelaic acid 
PRA: propionic acid 
IPD: isophorone diamine 
EDA: ethylene diamine 
RESIN PREATION 
The resins described in the Examples below were prepared by charging the 
acid and amine reactants shown in the Tables to a reactor along with about 
1% of an 85% solution of phosphoric acid as a catalyst. In Example 5, a 
portion of the MCD was indicated was reserved from the initial charge and 
added after most of the PRA had reacted. The reaction mixture was heated 
to 250.degree. C. and held for 2 hours at that temperature. The resulting 
resins had the softening point as determined by the Ball and Ring method 
and the acid value, reported in milligram KOH per gram of sample, in Table 
I below. 
The resins of Comparative Examples A, B and C were prepared using a 
polymeric fat acid available from Henkel Corporation as VERSADYME.RTM. 204 
which has the following analysis: 
______________________________________ 
Saponification Value (S.V.) 
198.5 
Acid Value (A.V.) 189.2 
Thermosel Viscosity (25.degree..) 
54.4 poises 
Color (Gardner - no solvent) 
7+ 
Fe 3.7 ppm 
P 25 ppm 
S 44 ppm 
Iodine Value 99.9 
% Monomer (M) 10.9 
% Intermediate (I) 5.3 
% Dimer (D) 71.1 
% Trimer (T) 12.6 
______________________________________ 
TABLE I 
__________________________________________________________________________ 
POLYAMIDE RESIN PREATION AND RESIN PROPERTIES 
Softening 
Acid Value 
PFA MCD ADA AZA PRA 
IPD 
EDA Point 
(mg KOH/g 
Example 
(eq.) 
(eq.) 
(eq.) 
(eq.) 
(eq.) 
(eq.) 
(eq.) 
(.degree.C.) 
sample) 
__________________________________________________________________________ 
1 -- 1 -- 3 -- 2.72 
-- 97 98.6 
2 -- 1 1 -- -- 1.4 
-- 126 93.0 
3 -- 1 1 -- -- 1.7 
-- 148.5 
35.1 
4 -- 1 1 -- -- 1.3 
-- 117.0 
85.4 
5 -- 3 -- -- 1 -- 3.28 
87 49.6 
A 1.25 
-- -- -- -- 1 -- 95 28.5 
B 1 -- 1 -- -- 1.7 
-- 124 30.0 
C 1 -- 1 -- -- 1.2 
-- 67.5 90.3 
__________________________________________________________________________ 
The solubility of the resins described in Table I in the following two 
solvents was determined. 
Solvent #1 was a mixture of 92.6% deionized and 7.4% dimethylaminoethanol. 
Solvent #2 was a mixture of 77.1% deionized water, 21.8% 
diethylaminoethanol, and 1.1% dimethylaminoethanol. 
The solubility of the resins in the indicated solvents are indicated in the 
table by the use of the following symbols: 
______________________________________ 
+ soluble/fluid - very high in viscosity 
- insoluble fluid 
-G insoluble/gel 
BG borderline gel 
+G soluble/gel 
______________________________________ 
The remaining symbols in the table indicate the Gardner-Holdt viscosity of 
the solution obtained by mixing the resin and the indicated solvent. 
TABLE II 
______________________________________ 
SOLUBILITY AND VISCOSITY OF POLYAMIDE RESINS 
SOLVENT #1 SOLVENT #2 
Resin solids (wt. %) 
EXAMPLE 40 30 20 40 30 20 
______________________________________ 
1 +G A1+ A4+ +G X+ A2- 
2 +G L+ A4 +G + A1 
3 BG Y+ A2 +G +G A-A1 
4 -G S A3 + Z4+ A-A1 
5 Z5-6 +G A X-Y +G A- 
A -G -G -- +G Z1 A2 
B BG -- -- +G Z1 A2 
C -G G- A2-3 + T-U A2 
______________________________________ 
The results shown in Table II show the representative resins of this 
invention have better solubility, particularly in a solvent having a very 
low concentration of organics, than the comparative polyamides prepared 
from polymeric fat acids. 
Samples of the polyamide resins shown in Table I were mixed with n-propanol 
and titanium dioxide to prepare white inks containing 33.3% by weight 
titanium dioxide, 20% by weight resin, and 46.7% by weight n-propanol. 
These inks were rolled out at 11/2 ml wet on glass to yield inks having 
the gloss shown in Table III. Samples of the inks were also rolled out on 
polyethylene and allowed to dry. The polyethylene samples were then 
immersed in water at 25.degree. C. for 24 hours. The samples were then 
subjected to 50 manual rubs with cotton wadding. The samples were rated on 
a scale of 1-10 with 10 representing a finding that the test had no effect 
on the ink coating. 
The gloss of the resulting inks and the results of the wet rub tests are 
shown in Table III below. 
TABLE III 
______________________________________ 
INK GLOSS AND WATER RESISTANCE 
GLOSS 
EXAMPLE 60.degree. 
20.degree. C. 
WET RUB 
______________________________________ 
1 85 16 10 
2 78 39 10 
3 76 45 10 
4 64 17 10 
5 67 20 10 
A 89 76 10 
B 82 51 10 
C 86 61 10 
______________________________________ 
The results shown in Table III indicate that the resins of this invention 
yield inks having good gloss and excellent resistance to water. 
EXAMPLE 6 
In this example, polyamides were prepared containing polymeric fat acids at 
a level of 12.5 equivalent percent, the lowest level shown in U.S. Pat. 
No. 3,776,865 to Glaser et al. A polyamide resin was also prepared from an 
acid component containing no polymeric fat acid, but having a low acid 
value of 16.5. These resins were evaluated and compared to the polyamide 
of Example 3 of the present invention, which has an acid value of 35.1. 
Five comparative resins were prepared using the Resin Preparation 
procedures disclosed earlier. In those resins employing a polymeric fact 
acid, a polymeric fat acid was employed having the same typical analysis 
given earlier. The amounts of the reactants, the acid value of the product 
and results of solubility of the products can be seen in the following 
Table IV. 
TABLE IV 
______________________________________ 
Acid 
Value Solubility 
Exam- Reactants (Ac- in Solvent 
ple PFA MCD ADA IPDA tual) C-1 C-2 
______________________________________ 
D 12.5 37.5 50 84.4 37.2 IS Gel 
E 12.5 -- 87.5 89.6 35.7 Gel Gel 
F -- 50 50 92.9 16.5 IS-PS IS-Gel 
G 12.5 37.5 50 93.2 14.4 IS-PS IS-Gel 
H 12.5 -- 87.5 96.6 11.4 IS-PS IS-Gel 
Exam- -- 50 50 85 35.1 T-U* Gel 
ple 3 
______________________________________ 
IS = Insoluble 
PS = Phase Separation 
* = Gardner Holdt Viscosity 
C1 and C2 = Two Solvents described earlier and used in Table II 30% Resi 
Concentration by weight 
As can be seen from the foregoing, the resin of the present invention has 
better solubility than the comparative resins D, E, G and H prepared with 
12.5 equivalents of polymerized tall oil fatty acids and resin F (with no 
polymeric fat acid), resins D through F all having actual acid values 
below 30.