JPS61252213A - Polyamide/acrylic graft copolymer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to graft copolymers of polyamides and acrylic monomers; more particularly to a new method of grafting these two.

Problems with the Prior Art The use of polyamide resins and acrylic resins in printing inks is known. When polyamide resins are used in printing inks, excellent bond strength, adhesion, gloss, and printing properties can be obtained. However, polyamide resins are not water-dispersible and are therefore not useful in water-based inks. On the other hand, although acrylic resins are water-dispersible, polyamide resins do not impart desirable properties to the ink. Since these resins are not compatible with each other, when these two resin solutions are mixed, they separate into two layers.

Although a copolymer equivalent of these two incompatible resins would enable the preparation of excellent water-based inks, such copolymers have not been easily synthesized so far.

SUMMARY OF THE INVENTION A method of chemically grafting a polyamide with an acrylic monomer in an alcoholic solution in the presence of a free radical peroxide initiator and then adjusting the pH above 7 to obtain a water-dispersible copolymer. This provides a graft copolymer that maintains the desirable properties of each raw material.

(Means for Solving the Problems) A graft copolymer was synthesized by chemically grafting polyamide and acrylic monomers and retaining the desirable properties of each raw material. It was found to be suitable as a paint resin.

Any type of polyamide may be used as long as it is suitable for printing ink. For example, polyamides from polymerized fatty acids, alkylene diamines, and hexanoic acid as disclosed in U.S. Pat. No. 3,412,115, U.S. Pat. No. 28,533 (
Polyamides disclosed in Re) specifications and British Patent No. 1,236°088 are useful. Also, in U.S. Patent No. 3,778,394, a polymerized fatty acid-based polyamide modified with a rosin adduct is used. There is a disclosure. Polyamides commonly used in flexographic printing inks are reaction products of dimeric fatty acids, dicarboxylic acids, polyamines, and monocarboxylic acids.

Typical examples of dimeric fatty acids useful for producing polyamides include thermal polymers of soybean oil fatty acids and tall oil fatty acids, and depending on the type of raw materials and reaction conditions, dimer, trimer, and higher aliphatic acids can be produced. as well as a mixture of unreacted fatty acids. Various grades are available ranging from 95% by weight of dimer fatty acids to 35% by weight of trimer fatty acids, but 85-95% by weight of dimer fatty acids are available.
Preferably.

Dicarbonate 1gIG useful for producing polyamides
, having 2 to 25 carbon atoms, such as oxalic acid, fumaric acid, maleic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, sebacic acid, 1.
Included are 12-dodecanedioic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,3- and 1,4-cyclohexanedicarboxylic acid, naphthalene dicarboxylic acid, C-21 cycloaliphatic dicarboxylic acid, and the like. Preferred dicarboxylic acids are aliphatic dicarboxylic acids having at least 6, preferably from 6 to 12 carbon atoms, such as adipic acid and azelaic acid.

A large number of monocarboxylic acids are available for polyamide synthesis. These have the general formula ROOM, where R is alkyl, cycloalkyl and aryl. Representative alkyls having at least 1 to 24 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, butrabutyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl. , eicosyl, hexadecyl, and their isomers. Cycloalkyl includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,
and others are included.

Aryl includes phenyl, naphthyl and alkyl derivatives thereof. Preferred monocarboxylic acids include acetic acid, propionic acid, 2-ethylhexonic acid, pelargonic acid, decanonic acid, myristic acid, hexadecanonic acid,
Palmitic acid, stearic acid, oleic acid, lylunic acid,
Included are benzoic acid, salicylic acid, and mixtures thereof.

Organic diamines used for polyamide preparation have the general formula
HN-R-NH2<R' represents an aliphatic, aromatic, or cycloaliphatic hydrocarbon group), and includes aliphatic, cycloaliphatic, or aromatic diamines. Preferred diamines include ethylenediamine, 1,2-propylenediamine, 1°3-propylenediamine, 1,4-diaminobutane, p-xylenediamine, toxylenediamine, piperazine, 1,6-hexamethylenediamine,
1.5-pentamethylenediamine, 4.4°-methylenebis(cyclohexylamine), 1.2-diaminocyclohexane, 2.2-bis(4-cyclohexylamino)propane, isoboronediamine, polyglycoldiamine, cyclohexanebis (methylamine), bis-
1,4-(2°-aminoethyl)benzene, and others. The polyamine used for polyamide SI has the general formula 1-12N [(R”) 2NHI
.

(R1NH2 (wherein R' is the same as above, n is 1 to
3), which includes diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and others.

Preferred polyamides include dimeric fatty acids, azelaic acid,
Prepared from ethylenediamine and piperazine.
Dimer fat 1 (dimer content 83% or more),
Polyamides made from propionic acid, azelaic acid, ethylene diamine, and hexamethylene diamine are also preferred.

Each component is used in stoichiometric proportions so that polymerization proceeds to a high degree. It is known to those skilled in the art to prepare polyamide II in such a manner, first combining the acid component with an amine to form an amine salt of the acid component and then heating the salt to remove water to form the polyamide.

The average molecular weight m of the polyamide used in the present invention is at least 15,000, and when the copolymer obtained from this [J] is used in a water-based printing ink, stability is good, and the bond strength measured with an Instron measuring machine is at least 3
00 M linear inch (2,5 cm), preferably at least 400 (1/linear inch (2,5 α)). For molecular weights below 15,000, the resulting copolymer solution is left standing. This increases the viscosity, forms a gel, and is unstable, making it unsuitable for ink preparation.Moreover, in the case of low molecular weight polyamides, the resulting copolymer is generally 300 Q/linear inch (2.5 cm).
) and cannot be used in fields that require high bond strength, such as laminating inks, where it is necessary to avoid separation of the ink from the film surface and the formation of spots or decals during lamination.

Preferred acrylic monomers for preparing the copolymers of the present invention include acrylic acid and methacrylic acid, 01-018 alkyl esters of acrylic acid and methacrylic acid; human O-oxyalkyl acrylic acid and methacrylate; styrene and alkyl-substituted styrene; vinylbi-O-lidone. ; terpene derivatives of acrylic acid and methacrylic acid; acrylamide and methacrylamide; cyanoalkyl acrylic acid and methacrylate; and others and mixtures thereof.

Acrylic monomers useful in the present invention include propenone i! (acrylic acid) and 2-methylpropenoic acid (methacrylic acid). In addition to the acid itself, these yk derivatives can be used alone or in combination.

These derivatives have the general formula: %formula% It can be shown in

In the formula, R-H or CH3
Hydroxybutyl, 2-cyanoethyl R=-=H, CH
CHOR” 3° 2 R””-H, CHCH 3゛ 25・C3H7・04 H9 In addition, other vinyl monomers known to those skilled in the art may be used as long as they are easily copolymerized with acrylic acid and methacrylic acid. Can be used in the present invention. Among these are styrene, substituted styrenes, N-vinylvinylidene, butadiene, isoprene, N-vinylcarbazole,
Vinyl oxazoline esters and others are included.

Among the preferred monomers are methyl acrylic acid, acrylic acid, methyl methacrylate, isobornyl acrylate and methacrylate, hydroxylethyl acrylate and methacrylate, hydroxypropyl acrylate and methacrylate, ethyl methacrylate, butyl acrylate and methacrylate, Isobutyl methacrylate, styrene, N
-Vinylvinylidene and others are preferred. Preferred acrylic monomers are those that do not contain amino groups; the presence of amino groups results in the formation of a copolymer that suffers from solution stability and forms a gel when the solution is allowed to stand. Polyamide and acrylic monomer are generally added to the reaction solution in a ratio of 5 to 95:95 to 5 parts by weight. Particularly preferred is a polyamide:acrylic monomer ratio of about 40 to 9 G:10 to 60 parts by weight.

Each of the polyamide and acrylic monomers is present as an alcohol solution during the reaction. Alcohols include methanol and ethanol with 1 to 4 carbon atoms;
Examples include propyl alcohol, butyl alcohol, and mixtures thereof, but are not necessarily limited to these aliphatic alcohols.

Initiators for free-radical graft polymerization include acyl peroxides, dialkyl peroxides, peroxy esters, hydroperoxides, and others in the acrylic moiety!
It is used in an amount of about 3-15% on an i basis. This peroxide free radical initiator is used to promote grafting of acrylic monomer onto the polyamide. Generally, at least 15%, and preferably at least 20%, by weight of the copolymer is comprised of polyamide-acrylic graft copolymer in order to obtain a copolymer with desirable properties. Peroxyester is a preferred initiator because it has a high conversion rate of acrylic monomer to polymer and also has a high grafting efficiency of acrylic monomer onto polyamide. Other free radical initiators, such as azo compounds, are not preferred because they have low conversion of acrylic monomers to polymer and do not tend to promote grafting onto polyamides.

The basics of the polymerization reaction are as follows.

Polyamide + Acrylic Monomer -> Polyamide + Acrylic Graft Polyamide + Acrylic Polymer Generally, this grafting reaction occurs in the range of about 60-115°C, preferably about 75-115°C. The viscosity of the resulting copolymer solution is 5 to 2 at a solids content of 40 to 60% when measured at room temperature using a Brookfield viscometer.
A range of 50 poise is preferred.

According to the method of the invention, at least one acrylic monomer is obtained grafted onto a polyamide skeleton. The resulting polyamide has grafted acrylic side chains. This acrylic moiety is grafted onto the dimer acid moiety of the polyamide by abstraction of frilled H atoms.

By the free radical grafting method of the present invention, a polymer having a structure in which polyamide and acrylic polymer, which are normally incompatible with each other, are copolymerized with each other can be obtained, and this polymer has the excellent bond strength, adhesion, and In addition to possessing gloss and printing properties, water-dispersibility occurs due to the carboxyl groups of the grafted acrylic moieties, resulting in water-based inks such as flexographic and gravure printing inks on substrates such as packaging films. A copolymer is obtained which is particularly suitable as a varnish.

One of the very important proposals of the present invention involves neutralizing the produced copolymer by adding a base, such as an amine. Acidic graft copolymers do not become water-dispersible as they are. The solution is neutralized to a pH of at least 7, preferably 8.5 to 10, so that a water-dispersible ink can be prepared from the neutralized varnish. The term water dispersible herein refers to the ability to form a homogeneous aqueous colloidal dispersion, rather than a heterogeneous dispersion, containing at least 211.

The advantage of using amines to neutralize and solubilize is that these volatile amines do not corrode equipment during the printing and drying process. Conventional copolymers having amine groups are solubilized by being neutralized with volatile acids such as hydrochloric acid and acetic acid, so there is a concern about corrosion. Preferred amines include ammonia, dimethylethanolamine, diethylethanolamine, 2-methyl-2-aminopropanol, triethanolamine, jetanolamine, N,N-dimethyl-2-methyl-2-aminoprobanol, and others. .

(Examples) Hereinafter, the present invention will be described in detail with reference to Examples, but there is no way to limit the invention to these Examples unless it departs from the gist of the present invention. Also, throughout this specification, all temperatures are in degrees Celsius and parts and percentages are by weight unless otherwise specified.

Polyamide (molecular weight 28
．． Goo 210 parts, n-propyl alcohol 362 parts
．． Three parts were placed in a four-sided round bottom flask under a nitrogen blanket, and gradually heated to reflux while stirring. This reflux completely dissolved the polyamide.

Methyl methacrylate was then added to the polyamide solution for 1±174 hours while refluxing at 95-100°C.
1.7 parts, 11128.5 parts of glacial acrylic, 8.92 parts of human O-oxypropyl methacrylate, 92.1 parts of n-propyl alcohol, and 2.94 parts of benzoyl peroxide.
part was dripped.

(B) After 1 hour, 2°68 parts of benzoyl peroxide,
1/4 of a mixture consisting of 20.1 parts of methyl ethyl ketone
The remainder was added in hourly portions over 3 hours. Refluxing was continued until solids analysis confirmed that the acrylic acid monomer had completely reacted.

The product was then cooled to room temperature and poured off.

The polyamide/acrylic weight ratio of the produced copolymer is 70
/ 30, and the solution viscosity at 40% solids is 24
It was Poise. The viscosity of this solution did not change even after being left for a day and night, indicating good stability.

337 parts of polyamide (molecule Wi 28,000, synthesized from piperazine, ethylenedi7mine, azelaic acid, and dimer fatty acid), and 5 parts of n-propyl alcohol
30.31 parts were charged into a stainless steel reactor. Reflux (97°C) was carried out under nitrogen blanket.

Then methacrylic acid-t was added under reflux for 1 hour.
11.9 parts of art-butyl, 11.9 parts of ethyl acrylate
parts, ice acrylic t, 29.7 parts, hydroxylethyl acrylate 5.9 parts, n-propyl alcohol 59.5 parts
and 97% tert-butyl neodecanoate.
A mixture consisting of 0 parts was added. The mixture was further refluxed for 1 hour.

(B) After 1 hour, 1/4 of a mixture consisting of 969 parts of n-propyl alcohol and 1.8 parts of tert-butyl neodecanoate was added, and the remainder was added in portions every hour over the next 3 hours. did.

The reaction was continued until the product contained 40% non-volatile solids. Next, 200 parts of the solvent was distilled off, and the mixture was cooled to 60° C. and filtered.

The polyamide/acrylic weight ratio of the copolymer produced was 85.
/15, solid content 50.2%, viscosity at 25°C is 12
It had a theoretical acid value of 1 poise and a theoretical acid value of 44, and its viscosity did not change even after being left for a day and night, indicating good stability.

The procedure of Example 2 was repeated, except that IL-eupolyamide (928,000 molecules) was synthesized from sebacic acid instead of azelaic acid. The viscosity of the produced copolymer solution increased when it was left for a day and night, and its stability was inferior to that of the copolymer solution of Example 2 using azelaic acid.

Ura Imperial Seal-1 (A) 216 synthesized from ethylenediamine, hexamethylenediamine, propionic acid, and dimer aliphatic acid
．． 0 parts of alcohol-soluble polyamide (molecular weight s, oo
o) and 329.9 parts of n-propyl alcohol were charged into a four-bottle round bottom flask under a nitrogen blanket and gradually heated to reflux while stirring. Refluxing completely dissolved the polyamide.

Next, 1124.0 parts of ice acrylic was added to this polyamide solution for 1 hour while refluxing at 90 to 100°C.
24.0 parts of n-propyl alcohol and 0.79 parts of benzoyl peroxide were added dropwise.

(B) After 1 hour, only 1/4 of the mixture consisting of 6.1 parts of methyl ethyl ketone and benzoyl peroxide Q, 721 was added, and the remainder was added in 3 portions every hour.

(C) After 3 hours, a solution of 0.72 parts of benzoyl peroxide in 6.1 parts of methyl ethyl ketone was added. Refluxing was continued until analysis of the solids indicated complete conversion of the acrylic monomer.

Traces of unreacted material were removed by removing 20% of the solvent.

The polyamide/acrylic weight ratio of the copolymer produced is 90/1
The viscosity of the 0.45% solids solution was 15 poise.
However, when it was left for a day and night, it was found that the viscosity increased and the stability was poor.

Example 5 Flexographic printing ink (A) 60.8 parts of the product of Example 2 were mixed with 31.8 parts of water, 3.4 parts of ethanol, 2.0 parts of 28% aqueous ammonia, and 2.0 parts of diethylethanolamine. mixed with.

(B) 48.5 parts of the varnish obtained in <A> above, 26.1 parts of titanium dioxide, and water/ethanol (80/
20) 25.4 parts of the mixture was added under high speed stirring to make a white ink.

(C) This ink was applied onto polypropylene film using a Flexographic Hand Bruf 7. This ink has printing properties, gloss, stability,! 5 Adhesion was good, the bond strength was at least 400 g/linear inch (2.5 cm+) as measured on an Instron tester, and the crinkle resistance was also good.

The following experiment was conducted to demonstrate the need to copolymerize Tomonao Mame-Tama polyamide and acrylic monomer.

Run (operation A1 was repeated, except that the acrylic monomer was polymerized without the presence of polyamide).

The acrylic polymer was then added into the polyamide solution.
These two solutions were not compatible, and precipitation of the acrylic polymer occurred.

Example 7 A polyamide/acrylic graft copolymer was synthesized according to the following recipe.

(1) Polyamide 408.0 parts (
Molecular weight approximately 11,000) (2) n-propatool 642.6
(3) Isobutyl methacrylate 14.4 (4)
Methyl methacrylate 14,4 (5) Acrylic acid 36.0 (6) Hydroxylpropyl acrylate 7,2 (7) Tert-Butylberoctoate 2,38 (8) n-Propatol 72.0 (9) tert-butyl octoate 2.16 (10) n-propenol 12.2 (A) dimer acid 8
408 parts of polyamide synthesized from 3% dimer, 17% trimer), propionic acid, azelaic acid, ethylene diamine, and hexamethylene diamine and 642.
6 parts of n-propyl alcohol were charged into a four-sided round bottom flask under a blanket of nitrogen and slowly heated to reflux with stirring, thereby dissolving all the polyamide.

Next, 14.4 parts of isobutyl methacrylate, 14.4 parts of methyl methacrylate, 1136.0 parts of 1% glacial acrylic, 7.2 parts of hydroxylpropyl acrylate, 72.0 parts of n-propyl alcohol, and tert-butyl ber. A mixture of 2.38 parts of octoate was added to the polyamide solution at 90-100° C. while refluxing at 1.1/4.
It was dripped over time.

(B) After 1 hour, 5-butylberoctoate 2.16
and 12.2 parts of n-propanol; the remainder was refluxed in three portions of 1 hour each until the solids indicated that the acrylic monomer had completely reacted. The product was then cooled to room temperature and removed as a 45% solids solution.

The polyamide/acrylic weight ratio of the produced copolymer is 85/1
5. The solution viscosity was 8 poise (using a Brookfield viscometer, solid content 45%, temperature 9!).

An aqueous varnish was made in WA according to the following recipe.

(1) Polyamide/acrylic graft copolymer composition (
Example 7) 60.1 parts (2) Water 36.1 (3) Diethylethanolamine 1.9 (4) Ammonium hydroxide solution 1.9 These components were placed in an Osteragoza and mixed for about 15 minutes. The produced varnish was cooled to room temperature and taken out.

A water-based ink was prepared using this varnish according to the following recipe.

(1) Varnish (above) 55 parts (2) Titanium dioxide 25.0 (
3) 8G/2G (w/w) water/ethanol 10.
0 These ingredients were placed in a male riser and stirred for about 30 minutes.

A Zahn #2 cup reading was adjusted to 25 seconds using a water-ethanol mixture (80720 Jyusha) as a diluting solvent. Add amine as needed to adjust pH to 9,0-9.
Adjusted to 5.

The printability of the final ink was good, but:
Poor ink stability and bond strength were observed.

Instability was evidenced by a significant increase in viscosity after 24 hours. The laminate bond strength measured by an Instron bond strength tester was 50-80 g/linear inch.

Tomo 1M8 The reaction was carried out using the following recipe.

(1) Polyamide (molecular weight approximately 15,000) 204.0 parts (2) n-propertool 321.0
(3) Methyl methacrylate 7.2 (4)
Isobutyl methacrylate 7.2(5) Acrylic acid 18.1(6) Hydroxypropyl acrylate 3,6(7) Tart-butylberoctoate 1.19(8) N-propatol 36.0(9) tert-Butylberoctoate 1.08 (10) n-prop/- 6.10 The reaction was carried out in the same manner as described in Example 7. The polyamide/acrylic weight ratio of the copolymer is 85/1
The viscosity at 5.45% solids was 20 poise.

The resulting water-based ink exhibits excellent adhesion printing properties, excellent stability and crinkle resistance (both dry and wet),
It also showed that the block resistance on the polyolefin film was excellent. Bond strength is soog/
It was more than a linear inch (2.5α).

11ri-1 The reaction was carried out according to the following recipe.

(1) Bo IJ 7 Mid 204.
071 (molecular weight approximately 5,000) (2) n-propatool 321.3
(3) Methyl methacrylate 7.28 (
4) Isobutyl methacrylate 7.2 (5) Acrylic acid 18.0 (6) Hydroxypropyl acrylate 3.6 (7) tert-
Butylberoctoate 1.19(8) n-propertool 36.0(9) ter
t-Butylberueoctoate 1.08 (1G)
n-Propatool 1.10 The reaction was carried out in a manner similar to that described in Example 7. It was not possible to prepare an ink because the copolymer solution was unstable and caused gelation of the varnish.

Song jl! 611 1st The following prescription was used to counteract the law.

(1) Polyamide 204.0 parts (
molecular weight approx. 28,000) (2) n-propatool 321.3
(3) Isobornyl methacrylate 72 (4) Isobutyl methacrylate 7.2 (5) Acrylic acid 18.0 (6) Hydroxypropyl acrylate 3.6 (7) Tert-Butyl peroctoate 1819 (8) n -Propatol 36,1(9) to tert-butylberoctoate-1 1.0(10)n-propatol 6.1 The reaction was carried out according to the method of Example 7.

The polyamide/acrylic weight ratio of the copolymer is 85/15.
The solution viscosity at 45% solids was 53 poise. The resulting water-based ink exhibited good adhesion and excellent block resistance with a bond strength of 5000/linear inch (2,57:I) as measured by an Instron bond strength tester.

Example 11 The reaction was carried out according to the following recipe.

(1) Polyamide 210.0 parts (molecular weight approximately 45,500) (2) n-propertool 363.3
(3) Isobornyl methacrylate 26.8 (4
) Isobutyl methacrylate 25.0 (5) Acrylic acid 28.5 (6) Hydroxypropyl acrylate 8.9 (7) ter
t-Butyl peroctoate 2.94 (8) n-propertool 92.1 (g) te
rt-butyl peroctoate 2.68 (10)
n-Propertool 2.68 The reaction was carried out according to the method of Example 7. Copolymer polyamide/
The acrylic weight ratio was 70/30.45% solids solution had a viscosity of 200 poise. The resulting water-based ink exhibited excellent adhesion, stability, printing properties, and crinkle resistance, with a bond strength greater than 400 g/linear inch (2,5α) as measured by an Instron bond strength tester. It showed block resistance.

Example 12 The reaction was carried out according to the following recipe.

(1) Polyamide 168.0
parts (molecular weight approximately 45.000) (2) n-propatool 288.71
(3) Methyl methacrylate 40,8 (
4) Acrylic acid 24.0 (5
) Dimethylaminoethyl methacrylate °7.2 (6)
tert-butylperoctoate-1-2.3
8(7)n-Proper Tools 72
．． 0(a) tart-butyl peroctoate
2.16(9) n-proper tool
6.1 The reaction was carried out in the same manner as in Example 7.

Since an acrylate containing an amino group was used, the ink prepared from the resulting copolymer had poor printing properties, poor storage stability, and increased viscosity when left overnight.

Example 13 The reaction was carried out according to the following recipe.

(1) Polyamide 210.0 parts (molecular weight 28,000) (2) Robanol 363.3
(3) Isobutyl methacrylate 26.8 (4
) Isobornyl methacrylate 25.0 (5) Acrylic 199 28.5 (6) Hydroxypropyl acrylate 8.9 (7) n-bu[1panol 92.1 (8) Azobisisobutyronitrile 2.94 (9) n-propatol 2.68 (10) Azobisisobutyronitrile 2.68 The reaction was carried out in the same manner as in Example 7. Even after neutralization, the water-dispersibility was poor and no ink could be prepared from this varnish.

1 other person

Claims (20)

[Claims] (1) A method for producing a water-dispersible polyamide/acrylic graft copolymer by free radical graft copolymerization of at least one acrylic monomer onto a polyamide skeleton, the method comprising the presence of a free radical peroxide initiator. A method comprising reacting a polyamide and an acrylic monomer in an alcoholic solution and then adjusting the pH of the copolymer solution to 7 or higher to obtain a water-dispersible copolymer solution. (2) The method according to claim 1, characterized in that the reaction temperature is 60 to 150°C. (3) Polyamide:acrylic weight ratio of 5 to 95:95
5. The method according to claim 2, characterized in that: (4) A method according to claim 3, characterized in that the polyamide has a molecular weight of at least 15,000. (5) The polyamide is a dimeric fatty acid, a dicarboxylic acid,
5. The method according to claim 4, which is a reaction product of a polyamine and a monocarboxylic acid. (6) The method of claim 5, wherein the free radical peroxide initiator is a peroxyester. (7) The method according to claim 6, wherein the acrylic monomer does not contain an amino group. (8) The acrylic monomer is selected from the group consisting of methyl methacrylate, isobutyl methacrylate, hydroxypropyl acrylate, isobornyl methacrylate, acrylic acid, and mixtures thereof. Method described. (9) The method according to claim 2, wherein the reaction temperature is 15 to 115°C. (10) The weight ratio of polyamide:acrylic is 40 to 90:
Claim 3, characterized in that the number is 10 to 60.
The method described in section. (11) The method according to claim 1, characterized in that p of the copolymer solution is adjusted to 8.5 to 10. (12) The method according to claim 11, characterized in that the pH of the copolymer solution is adjusted with an amine. (13) The method according to claim 4, wherein the solid content is 40 to 50% and the viscosity of the copolymer solution measured at room temperature is 5 to 250 poise. (14) The method according to claim 13, wherein the viscosity of the copolymer solution does not change even if left for a day or night. (15) Claims 1, 4, 6, and 8
A water-dispersible polyamide/acrylic graft copolymer prepared by the method according to any one of Items 1, 12 and 14. (16) Claims 1, 4, 6, and 8
15. A water-based printing ink containing, as a resin component, a water-dispersible polyamide/acrylic graft copolymer prepared by the method according to any one of Items 1, 12 and 14. (17) The water-based printing ink of claim 16, wherein the ink has a bond strength of at least 300 g/linear inch (2.5 cm). (18) At least 15% by weight of the copolymer contains as a resin component a water-dispersible polyamide/acrylic graft copolymer comprising a polyamide/acrylic graft copolymer, and the bond strength of the ink is at least 300 g/linear inch ( 2
．． 5cm) water-based printing ink. (19) The printing ink according to claim 18, wherein the ink has a bond strength of at least 400 g/linear inch (2.5 cm). (20) Printing ink according to claim 19, characterized in that the polyamide used to prepare the copolymer has a molecular weight of at least 15,000.