JPH0841402A - Printing ink and resin composition therefor - Google Patents

Abstract

PURPOSE:To provide a resin composition for printing ink, containing a specified polyamide-modified chlorinated polypropylene and a polyamide, excellent in adhesion, shelf life, color development and printability and useful for, e.g. coating of plastic film, etc. CONSTITUTION:This resin composition for printing contains (A) a polyamide- modified chlorinated polypropylene synthesized by reacting (i) a polyamide having primary or secondary amino groups with (ii) a chlorinated polypropylene having isocyanate groups and having 3100 to 10000O weight-average molecular weight and (B) a polyamide. In addition, the mixing ratio of the component (A) to the component (B) is 3/97 to 50/50 by weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing ink resin composition and a printing ink containing the resin composition. More specifically, the present invention relates to a resin composition for printing ink and a printing ink which are particularly useful for coating various plastic films, plastic sheets or synthetic resin molded products.

[0002]

2. Description of the Related Art In recent years, with the diversification of objects to be packaged and the sophistication of packaging technology, when various plastic films are used as packaging materials, the plastic films are printed for decoration or surface protection. However, printing inks for such printing are required to have high performance and quality. In particular, a wide range of adhesiveness to various plastic films has become necessary for making packaging containers more beautiful and sophisticated. Generally, methods such as gravure printing and flexographic printing are used for printing plastic films, etc., and in the case of film printing as a packaging material, most of them are winding methods, so that the printing ink is required to have quick drying properties. When used as a packaging for food, it is required that the residual solvent content is low.

In printing inks, the adhesion to various substrate films is mainly determined by the binder resin used in the printing ink. Conventionally, as a binder for printing inks, nylon, polyester, treated polyolefins, and polyamide resins having a wide range of adhesiveness to other substrate films have been used. However, a printing ink using a polyamide resin as a binder has sufficient adhesiveness alone to nylon films, polyester films and treated polyolefin films, but sufficient adhesiveness to untreated polyolefin films cannot be obtained. I want to.

Further, it has been attempted to mix a chlorinated polyolefin and a polyamide for the purpose of improving the adhesiveness to an untreated polyolefin film, but the two have poor compatibility and a printing ink using this as a binder is stable. Insufficient properties, color development and printability.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printing ink having excellent adhesiveness to nylon films, polyester films and untreated polyolefin films, and having sufficient stability, color development and printability. It is in.

[0006]

That is, the present invention provides a polyamide (a) having a primary or secondary amino group and a chlorinated polypropylene (b) having an isocyanate group in the molecule.
The present invention provides a resin composition for printing ink, comprising a polyamide-modified chlorinated polypropylene (A) obtained by reacting with and a polyamide (B), and a printing ink containing the resin composition.

The polyamide (a) having a primary or secondary amino group can be obtained by polycondensing a polybasic acid and a polyvalent amine with the functional group ratio of the acid and the amine being NH ₂ / COOH> 1. Those having a molecular weight of 600 to 100,000, and more preferably 1000 to 50,000 are preferably used. When the molecular weight is less than 600, the compatibility is insufficient, and when it exceeds 100,000, the stability of the ink tends to decrease.

As the polybasic acid, for example, adipic acid,
Examples thereof include sebacic acid, isophthalic acid, terephthalic acid, trimellitic acid, cyclohexanedicarboxylic acid, and polymerized fatty acids such as aliphatic, aromatic, and alicyclic compounds. Above all,
Polymerized fatty acid is preferable, and as a representative example of the polymerized fatty acid,
The following composition called dimer acid obtained by polymerizing a C ₁₈ unsaturated fatty acid or a lower alkyl ester (C _{1 to} C ₃ ) thereof can be mentioned. C ₁₈ monobasic acids: Normal 0-15 wt% (preferably 0-7 wt%) C ₃₆ dibasic acid: Normal 60-100 wt% (preferably 75 to 10
0% by weight) C ₅₄ or more polybasic acid: usually 0 to 25% by weight (preferably 0% by weight)
A monocarboxylic acid may be used in combination with the polybasic acid. Examples of the monocarboxylic acid include aliphatic, aromatic and alicyclic acid such as acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid and cyclohexanecarboxylic acid.

Examples of the polyvalent amine include aliphatic and aromatic compounds such as ethylenediamine, diethylenetriamine, triethylenetetramine, 1,2-diaminopropane, 1,3-diaminopropane, hexamethylenediamine, xylylenediamine and isophoronediamine. And alicyclic ones.

The chlorinated polypropylene (b) having an isocyanate group is a chlorinated polypropylene (c) having a hydroxyl group and a diisocyanate (d), and the functional group ratio of isocyanate group / hydroxy group is NCO / OH = 1.8 to 2.5, preferably Is 2.0 to 2.3, reaction temperature is 30 to 90 ° C, reaction time is 0.5
It can be produced by reacting for about 20 hours. A commercially available product can be used as the chlorinated polypropylene (c) having a hydroxyl group, and the hydroxyl group equivalent represented by the resin weight per hydroxyl group is 500 to 30.
It is preferably 00, more preferably 1000 to 2000. If the hydroxyl equivalent exceeds 3000, it is difficult to obtain the effect of compatibilization by modification with the polyamide (a) having a primary or secondary amino group, and if it is less than 500, the adhesion to the substrate decreases, which is preferable. Absent.

The degree of chlorination of the chlorinated polypropylene (c) having a hydroxyl group is preferably 10 to 60, particularly 25.
Those in the range of to 45 are preferred. If the chlorination degree is less than 10,
Solubility in organic solvents is low, and when it exceeds 60, the adhesion to polyolefins and other substrates decreases. Furthermore, the weight average molecular weight of the chlorinated polypropylene (c) having a hydroxyl group is preferably in the range of 3,000 to 100,000, more preferably 5,000 to 30,000. If the weight average molecular weight is less than 3000, the adhesion to the substrate will be reduced, and if it exceeds 100000, the compatibility will be poor and the object of the present invention will not be achieved.

Examples of the diisocyanate (d) include aliphatic and aromatic compounds such as 4,4'-diphenylene methane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate.
Various known ones such as alicyclic can be used.

The polyamide-modified chlorinated polypropylene (A) of the present invention comprises a polyamide (a) having a primary or secondary amino group and a chlorinated polypropylene (b) having an isocyanate group at a reaction temperature of 10 to 70 ° C. Reaction time 0.5〜
It can be obtained by reacting for about 20 hours. Level 1 or 2
The ratio of the polyamide (a) having a primary amino group and the chlorinated polypropylene (b) having an isocyanate group is such that the functional group ratio of amino group / isocyanate group NH ₂ /NCO=1.0 to 3.0.
The range is good, and further 1.0 when the polyamide (a) has a primary or secondary amino group at one end, and 1 at both ends.
When it has a secondary or secondary amino group, it is preferably 2.0 to 2.3. If it is less than 1.0, the isocyanate group remains and the stability after ink formation becomes unstable. The weight average molecular weight of the polyamide-modified chlorinated polypropylene (A) is 3100 to 100,000.
The range is more preferably 5000 to 50000. If it is less than 3100, the blocking resistance tends to decrease, and if it exceeds 100000, the compatibility with the polyamide (B) decreases, which is not preferable.

As the polyamide (B), first-class or second-class
It is obtained by polycondensing the polybasic acid exemplified with the polyamide (a) having a primary amino group and a polyvalent amine, and has a molecular weight of 3000 to
Those of 100,000 and more preferably 5,000 to 50,000 are preferably used. The polyamide (B) may or may not have a primary or secondary amino group. Molecular weight 3000
If it is less than 100, the film strength and heat resistance tend to decrease,
If it exceeds the range, the resin solution is apt to gel and the dispersibility of the pigment tends to be deteriorated, which is not preferable.

In the resin composition for a printing ink of the present invention, the mixing ratio of the polyamide-modified chlorinated polypropylene (A) and the polyamide (B) is such that the weight ratio of the solid content is A /
B is preferably in the range of 3/97 to 50/50, more preferably 10/90 to 40/60. If the content of the polyamide-modified chlorinated polypropylene (A) is less than 3% by weight, it is difficult to obtain the adhesiveness to the untreated polyolefin, and if it exceeds 50% by weight, the blocking property tends to be lowered, which is not preferable.

In the case of producing a printing ink containing the resin composition of the present invention, various pigments and solvents are added to polyamide-modified chlorinated polypropylene (A) and polyamide (B), and the mixture is kneaded and dispersed. An antiblocking agent, an additive such as a plasticizer, a surfactant for improving ink fluidity and dispersibility, or nitrification cotton having compatibility,
Terpenoids, urea resins, maleic acid resins and the like can be used in combination. The resin solid content concentration in the printing ink is appropriately determined in consideration of workability during printing, printing effect, etc., and is not particularly limited, but usually 3 to 50.
It is better to adjust to the weight percent.

[0017]

The present invention is described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, "parts" and "%" in the examples represent "parts by weight" and "% by weight", respectively. [Production Example 1] A 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was used, and a 55% solid content toluene solution of chlorinated polypropylene having a hydroxyl group (“Super Clone” manufactured by Nippon Paper Industries Co., Ltd. 813A ", hydroxyl equivalent 1624, molecular weight 1
0000) 47.25 parts and isophorone diisocyanate 1.96 parts were charged and reacted at 80 ° C. for 6 hours. To the resulting chlorinated polypropylene containing isocyanate groups, 24.12 parts of solid content 50% toluene solution of polyamide having amine groups at both ends (amine equivalent 685, molecular weight 1370) was reacted at 50 ° C for 3 hours, and 26.67 parts of toluene was added. Resin solution a with solid content of 40%
(Molecular weight 20,000) was obtained.

[Production Example 2] 50.42 parts of a chlorinated polypropylene having an isocyanate group in the molecule obtained in the same manner as in Production Example 1 and a solid content 50 of a polyamide having an amino group and a hydroxyl group at the end (amine equivalent 1260.7). % Toluene solution
22.74 parts were reacted at 50 ° C. for 3 hours, and 26.84 parts of toluene was added to obtain a resin solution b (molecular weight 19,000) having a solid content of 40%.

[Production Example 3] Solid content of polyamide (amine equivalent 1286.7) having amino groups and alkyl groups at the ends in 50.12 parts of chlorinated polypropylene having isocyanate groups in the molecule obtained in the same manner as in Production Example 1. 23.08 parts of 50% toluene solution was reacted at 50 ° C for 3 hours to give 26.80 parts of toluene.
Parts were added to obtain a resin solution c (molecular weight 19,000) having a solid content of 40%.

[Examples 1-8 and Comparative Examples 1-2] Table 1
After adjusting the white printing ink by kneading in the mixing ratio shown in, after adjusting the viscosity of the resulting printing ink with a mixed solvent of toluene, isopropyl alcohol, ethyl acetate (weight ratio 60:30:10), The uncoated unstretched polypropylene was color-developed with a bar coater # 6, and the following tests were conducted. Table 2 shows the results.

[0021]

[Table 1] * 1 Polyamide (B) varnish Solid content 35% Toluene 43% Isopropyl alcohol
(IPA) 22% Molecular weight 8000 * 2 Nitrified cotton varnish Solid content 14% Toluene 32% IPA 30% Ethyl acetate 24
% * 3 Chlorinated polypropylene varnish “Super Clone 813A” manufactured by Nippon Paper Industries Co., Ltd. was diluted to a solid content of 24% with toluene. * 4 The amount of the raw material chlorinated polypropylene component used in Example 4 was added. * 5 Chlorinated polypropylene / polyamide (B ) Solid content ratio

1) Ink stability (compatibility) After the ink was allowed to stand at room temperature for 24 hours, the degree of separation was visually determined. ○ No separation △ Slight separation × Large separation 2) Adhesion Immediately after being applied to the film, it was dried for 10 seconds with a drier and allowed to stand for 20 seconds, a cellophane tape was attached to the printing surface, and the film was rapidly peeled off. Was visually evaluated. ○ 80% or more remained on the film △ 50% or more remained on the film × less than 50% remained on the film 3) Color development (gloss of coating film) The gloss of the developed product was visually judged. ○ Good △ Somewhat bad × Bad

[0023]

[Table 2]

[0024]

According to the present invention, it is possible to provide a printing ink having good adhesion to an untreated polyolefin film used as a material to be printed and having excellent physical properties such as storage stability and color development.

Claims (4)

[Claims] 1. A polyamide-modified chlorinated polypropylene (A) obtained by reacting a polyamide (a) having a primary or secondary amino group with a chlorinated polypropylene (b) having an isocyanate group, and a polyamide (B). ) And a resin composition for printing ink. 2. A polyamide-modified chlorinated polypropylene (A) having a weight average molecular weight of 3100 to 100000.
The resin composition for a printing ink as described above. 3. The resin composition for printing ink according to claim 1, wherein the weight ratio of the polyamide-modified chlorinated polypropylene (A) and the polyamide (B) is in the range of 3/97 to 50/50. 4. A printing ink comprising the resin composition for printing ink according to any one of claims 1 to 3.