JP3023188B2 - Resin composition for coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various plastics, especially polyolefin resins, which can be used for painting, bonding or printing various plastic molded articles and films including polyolefin resins. The present invention relates to a coating resin composition having excellent adhesion.

[0002]

2. Description of the Related Art In recent years, plasticization of various industrial members such as automobile parts, household electric parts, building materials, etc. has been rapidly promoted from the viewpoints of weight reduction, rust prevention measures, design freedom, and the like. Examples of plastic materials used for these include non-polar polyolefin resins such as polypropylene and polyethylene, polyamide, polybutylene terephthalate, polyurethane, unsaturated polyester, FRP,
Polycarbonate resins and their mixed plastics are widely used. However, these plastics, especially polyolefins, are generally difficult to paint, glue, or print, and are usually treated with flame, plasma, corona discharge, etc., prior to these operations. The fact is that the primer is applied.

[0003]

However, the above-described flame treatment, plasma treatment, and corona discharge treatment are insufficient for obtaining stable adhesion. Further, as a primer, a primer mainly composed of chlorinated polypropylene grafted with maleic anhydride is known, but this has a problem in cold resistance and pigment dispersibility. Α, β
-Primers mainly comprising a styrene / conjugated diene block copolymer grafted with an unsaturated dicarboxylic acid and / or an acid anhydride thereof (JP-A-61-192743, etc.) have been proposed. Stable adhesion is obtained, and although it is improved compared to the maleic anhydride-grafted chlorinated polyolefin primer with respect to cold resistance and pigment dispersibility, it is not always sufficient, and storage stability is also required to be further improved. That is the current situation. The present invention is a coating resin composition having stable adhesion to polyolefin, and when used as a primer, has excellent storage stability, pigment dispersibility, cold resistance, crosslinkability, and a primer. In addition, to provide coating resin compositions applicable to a wider range of applications as paints, inks, binders for adhesives, etc., which have stable adhesion to various plastics including polyolefins. It is.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have good adhesion to various plastics including polyolefins.
In particular, the present invention has found a composition excellent in storage stability, pigment dispersibility, cold resistance and crosslinkability, and has reached the present invention. That is, the present invention relates to a method for producing an α, β-unsaturated dicarboxylic acid and / or a hydrogenated product of a styrene / conjugated diene block copolymer.
Or a graft copolymer obtained by graft-polymerizing an acid anhydride thereof, wherein at least 25% of the total of the grafted α, β-unsaturated dicarboxylic acid and the acid anhydride in the graft copolymer is a monopolymer. The modified graft copolymer (A) which has been half-esterified with an alcohol and / or half-amidated with a mono-secondary amine, and a solvent (B) capable of dissolving or dispersing the modified graft copolymer (A) are used. An object of the present invention is to provide a coating resin composition as a main component.

Hereinafter, the present invention will be described in more detail. [Modified Graft Copolymer (A)] The modified graft copolymer (A) used in the present invention is obtained by adding an α, β-unsaturated dicarboxylic acid and / or an α, β-unsaturated dicarboxylic acid to a hydrogenated product of a styrene / conjugated diene block copolymer. It is suitably produced by graft-polymerizing an acid anhydride and then reacting the graft copolymer with a monoalcohol and / or a mono-secondary amine. The modified graft copolymer (A) can also be prepared by using a half-esterified and / or half-amidated α, β-unsaturated dicarboxylic acid and / or an acid anhydride thereof alone or α, β-unsaturated dicarboxylic acid. It can also be obtained by graft-polymerizing a hydrogenated styrene / conjugated diene block copolymer together with an acid and / or an acid anhydride thereof. In such a case, the graft polymerization can be carried out under the same conditions as those for the later-described graft polymerization of α, β-unsaturated dicarboxylic acid and / or an acid anhydride thereof. styrene·
Examples of hydrogenated conjugated diene block copolymers include styrene / butadiene diblock copolymers, triblock copolymers, hydrogenated products of tetra- or higher multiblock copolymers, and diblock copolymers of styrene / isoprene. Examples thereof include a hydrogenated product of a coalesced, triblock copolymer, or multiblock copolymer. These block copolymers are preferably those sold, for example, under the trade name of Clayton from Shell Chemical Co., Ltd., under the trade name of Tuftec from Asahi Kasei Corporation, and under the trade name of Septon from Kuraray Co., Ltd. Can be used for styrene·
Α, β- to hydrogenated conjugated diene block copolymer
The production of a graft copolymer obtained by graft-polymerizing an unsaturated dicarboxylic acid and / or an acid anhydride thereof is disclosed in, for example, JP-A-61-192743.
It can be obtained by graft polymerization of a hydrogenated styrene / conjugated diene block copolymer with an α, β-unsaturated dicarboxylic acid and / or an acid anhydride thereof in the presence of a radical polymerization initiator. The graft polymerization of half ester and / or half amide can be carried out under the same conditions. As a graft polymerization method, these raw materials are melt-kneaded using an extruder,
A method of performing graft polymerization at a temperature of from about 300 ° C. to about 300 ° C., or a method of heating and dissolving these in an organic solvent such as toluene, xylene, or chlorobenzene to perform graft polymerization at a temperature of from about 50 ° C. to about 200 ° C. The radical polymerization initiator may be any of ordinary radical initiators, such as alkyl peroxides such as ditertiary butyl peroxide and tertiary butyl hydroperoxide, and allyl peroxides such as dicumyl peroxide and cumyl hydroperoxide. Acyl peroxide such as dilauroyl peroxide; aroyl peroxide such as dibenzoyl peroxide; ketone peroxide such as methyl ethyl kent peroxide; azonitrile such as peroxycarbonate and azobisisobutyronitrile. . Unreacted α, β-unsaturated dicarboxylic acid and / or its anhydride can be easily removed by subjecting the reaction mixture to a vacuum treatment while heating and melting, or repeatedly washing the reaction mixture with a solvent such as acetone. However, half-esterification and / or half-amidation may be performed without purification. As the α, β-unsaturated dicarboxylic acid and / or its acid anhydride, maleic acid, itaconic acid, citraconic acid, chloromaleic acid, dimethylmaleic acid and acid anhydrides thereof are used. The amount of the grafted α, β-unsaturated dicarboxylic acid and / or acid anhydride in the modified graft copolymer (A) is preferably in the range of 0.1 to 10% by weight. When the graft amount is less than 0.1%,
Adhesion to polyolefins is good, but adhesion to polar substances such as paints, inks, adhesives and metals is inferior. On the other hand, even if the graft ratio exceeds 10%, adhesion to polar substances higher than that is not improved. You can't hope for it, which is uneconomical.

[Half-esterification and half-amidation] Half-esterification and / or mono-secondary amine of α, β-unsaturated dicarboxylic acid and / or anhydride thereof grafted on a graft copolymer with monoalcohol As a method of half amidation, a method of melt-kneading a graft copolymer, a monoalcohol and / or a monosecondary amine, and a catalyst, if necessary, using an extruder and reacting at 150 to 300 ° C, It is preferable to dissolve these raw materials in an organic solvent such as toluene, xylene, or chlorobenzene and react them at 0 to 200 ° C. The graft copolymer used for the half esterification and / or half amidation reaction contains unreacted α, β-
The product from which the unsaturated dicarboxylic acid and / or its acid anhydride has been removed may be used, or the product from which it has not been removed may be used. In the half esterification and half amidation reaction, a catalyst is not always necessary, but amines such as triethylamine, tributylamine and benzyldimethylamine; quaternary ammonium salts such as tetramethylammonium bromide and benzyltrimethylammonium chloride; A variety of catalysts such as sulfuric acid, strong acids such as paratoluenesulfonic acid, and metal oxides such as zinc oxide may be used.
However, when a strong acid is used, care must be taken because not only half-esterification but also diesterification easily occurs, so that the half-ester becomes a diester and the half-esterification rate may be reduced. The monoalcohol used for the half esterification is not particularly limited, but examples thereof include methanol, ethanol, propanol, butanol, hexanol, octanol, benzyl alcohol, phenethyl alcohol, N, N-dimethylaminoethanol, and alkylene oxide adducts thereof. Is done. Examples of the monosecondary amine used for half amidation include dimethylamine, diethylamine, dipropylamine, dibutylamine, N-methylcyclohexylamine, N-methylaniline, and the like. The amount of monoalcohol and / or monosecondary amine used is
It is necessary to use at least 25 mol% or more based on the total amount of the α, β-unsaturated dicarboxylic acid and / or its acid anhydride. There is no particular upper limit, but since these are generally poor solvents for the graft copolymer, it is desirable to use them to such an extent that solids do not precipitate. It is preferable that at least 25% of the total of the α, β-unsaturated carboxylic acid and / or the acid anhydride grafted in the modified graft copolymer (A) is half-esterified and / or half-amidated. preferable. When the total of the half-esterified and / or half-amidated α, β-unsaturated carboxylic acid and / or its acid anhydride is 25% or less, the effect of improving the pigment dispersibility, storage stability and the like is insufficient. It is. The half esterification rate or half amidation rate is
The amount of the half ester or half amide in the total of the grafted α, β-unsaturated dicarboxylic acid, its anhydride, half ester or half amide, and diester or diamide is indicated by mol%.

[Solvent (B)] Half esterification and / or
As the solvent (B) capable of dissolving or dispersing the modified graft copolymer (A) which has been half-amidated,
Aromatic hydrocarbons such as toluene, xylene and chlorobenzene, tetralin, mineral spirit, heptane, tetrahydrofuran and the like are used as the soluble solvent. Further, various polar solvents such as methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, ethylene glycol dimethyl ether, methyl cellosolve acetate, cellosolve, ethanol, propanol, and water are used as dispersants or diluents used in combination with the above-mentioned soluble solvents. Can be done. The amount of the solvent component (B) capable of dissolving or dispersing the component (A) is not particularly limited. However, from the viewpoint of easy handling and workability, the concentration of the component (A) is usually 1 to 60% by weight. It is desirable to use 4 to 50%, preferably 99 to 40% by weight, preferably 96 to 50% of the component (B). However, it is of course possible to use a concentration outside this range.

[Additives] The composition of the present invention contains various pigments, dyes, fillers, antioxidants, light stabilizers, ultraviolet absorbers, thixotropic agents, leveling agents, surfactants, and blocking agents. Various additives such as an inhibitor, a slip agent, an antistatic agent, a tackifier, a polyisocyanate compound, a polyepoxide, an alkyl etherified melamine formalin resin, various crosslinking agents such as a silane coupling agent, a chlorinated polypropylene, an acrylic resin, Various coating resins such as an unsaturated polyester resin, a polyurethane resin, an alkyd resin, a cellulose resin, a vinyl chloride / vinyl acetate copolymer, polyvinyl acetate, and a polyamide resin can be added and used.

[Application] The composition of the present invention is a primer for improving the adhesion to paints, adhesives and inks of various plastics such as polyolefins; and the adhesion of various paints, adhesives and inks for plastics. Binders for various plastic paints; Adhesives for heat sealing various plastics or between plastics and various metals, adhesives for dry lamination, pressure-sensitive adhesives, etc .; or binders for various plastic inks Provided is a coating resin composition which is useful as, for example, and has excellent adhesion to various plastics. The coating amount of the composition of the present invention varies depending on the required performance and the object, but is usually applied using a spray, a brush, a coater, a printing machine, or the like such that the thickness of the dried film is 0.1 μ to 100 μ. .

[0010]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these examples. Comparative Example 1 100 g of a hydrogenated styrene-butadiene-styrene block copolymer (abbreviated as SEBS) was placed in a glass flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer.
(Clayton G-1652, manufactured by Shell Chemical Co., Ltd.), 300 g of xylene, the inside of the system was replaced with nitrogen, the temperature was raised to 125 ° C., and a solution of 10 g of maleic anhydride and 1 g of dicumyl peroxide dissolved in 200 g of xylene Was added dropwise over 10 hours. After completion of the reaction, the system was cooled to around room temperature,
Acetone was added to reprecipitate the maleated SEBS, followed by filtration and drying to give a white powdery graft resin. From the results of infrared absorption spectrum measurement and neutralization titration of this graft-modified resin, the content of maleic anhydride was 4.2% by weight. Next, 20 parts by weight of the graft resin was dissolved by heating in a mixed solvent of 60 parts of toluene, 10 parts of xylene, and 10 parts of methyl ethyl ketone to obtain a 20% solution of the graft resin.

Example 1 20 of the maleic anhydride graft resin obtained in Comparative Example 1
The half esterification reaction was carried out by charging 100 parts of the 100% solution and 2 parts of ethanol into the same reactor as used in Comparative Example 1 and heating and reacting at about 80 ° C. for 12 hours.
After completion of the reaction, a large amount of acetone was added to the reaction solution, and the precipitated solid was filtered and dried to obtain a modified graft copolymer (A) in which about 85% of maleic anhydride was half-esterified. The half esterification ratio was determined from the infrared absorption spectrum of (A). Next, 20 parts of the modified graft copolymer (A) were mixed with 60 parts of toluene and 10 parts of xylene.
And a mixture of 10 parts of methyl ethyl ketone by heating to obtain a coating resin composition having a solid content of 20%.

Comparative Example 2 The hydrogenated styrene butylene block copolymer was replaced with 100 g of hydrogenated styrene isoprene styrene block copolymer (SEPS) (Septon 2002, manufactured by Kuraray Co., Ltd.), and the amount of maleic anhydride was reduced to 5 g. Comparative Example-
Synthesized in the same manner as 1 to give a 40% solution of graft resin with 2.4% maleic anhydride grafted.

Example 2 N, N was added to 100 parts of the graft resin solution obtained in Comparative Example 2.
After adding 3 parts of N-methylcyclohexylamine and thoroughly mixing, the mixture was allowed to stand at room temperature for 3 days to modify the graft ratio of maleic anhydride to 2.4% and about 95% of maleic anhydride to be half amidated. A 40% solution of the graft resin was obtained.

Example 3 SEBS used in Comparative Example-1 was added to a resin having a hydrogenated styrene-butadiene diblock copolymer (abbreviated as SEB) as a main component (Clayton G1726 manufactured by Shell Chemical Co., Ltd.) and maleic anhydride. The graft reaction was carried out in the same manner except that the amount of the acid was changed to 20 parts. When a small amount of the reaction solution was taken out and the graft resin was purified and analyzed, the graft ratio of maleic anhydride was 5.8%.
Met. Next, 1-butanol 30 was added to the reaction solution.
The mixture was further reacted at 100 ° C. to 105 ° C. for 2 hours. Thereafter, the same post-treatment as in Comparative Example 1 was carried out to remove ungrafted maleic anhydride and monobutyl maleate. The graft ratio of maleic anhydride was 5.8%, of which about 40% was A 30% solution of the half-esterified modified graft resin was obtained.

Comparative Example 3 The reaction was carried out in the same manner as in Example 3 except that the amount of 1-butanol used was changed to 5 parts and the esterification time was changed to 20 minutes.
A 30% solution of a modified graft resin having a graft ratio of maleic anhydride of 5.8% and a half esterification ratio of 13% was obtained.

Example 4 A graft reaction was carried out in the same manner as in Comparative Example 1 except that maleic anhydride (10 parts) was changed to monooctyl maleate (20 parts). A 20% solution of a modified resin having an esterification rate of 100% was obtained.

Example 5 30% solution 1 of the modified graft resin obtained in Example-3
In 00 parts, 80% of sodium dioctyl sulfosuccinate
Phase inversion emulsification was carried out by dissolving 0.4 part of the solution and gradually adding distilled water 150 under strong stirring. Next, one drop of Nopco 8034 manufactured by San Nopco Co., Ltd. was added as an antifoaming agent to the obtained emulsion, and the organic solvent was azeotropically distilled off under reduced pressure to obtain an aqueous dispersion having a modified graft resin concentration of 40%. Was. Table 1 shows the contents of the coating compositions of Examples 1 to 5 and Comparative Examples 1 to 3 and the evaluation results of storage stability.

[0018]

[Table 1]

Application Examples 1 to 7 and Comparative Application Examples 1 to 3 ( Examples of Application to Coating Primer) A primer for plastic coating was prepared using the coating resins of Examples and Comparative Examples, and the pigment dispersion of the undiluted primer solution was prepared. Table 2 shows the results of evaluation of the properties. In addition, a crosslinking agent may be further added to the primer stock solution in some cases, and except for Application Example 5, a dilution solvent having a mixing ratio of xylene / toluene of 1/1 is used.
The liquid adjusted to have a viscosity of 20 seconds is sprayed with an air gun onto the coating substrate shown in Table 2 so that the dry film thickness becomes about 10 μm. In the case of Application Example 5, the dry film thickness is obtained using a bar coater. It is applied so as to have a role of 10μ, and a commercially available 2
A liquid type urethane paint was spray-coated so as to have a dry film thickness of about 40 μm, and baked at 80 ° C. for 1 hour to prepare a test piece for evaluation. After leaving the coated test piece in a constant temperature room at 23 ° C. for one week, the coating film was evaluated. Table 2 shows the evaluation results.

[0020]

[Table 2]

Application Examples 8 to 12 and Comparative Application Examples 4 to 6 ( Application Examples for Adhesives for Heat Seal Labels) The alicyclic petroleum resins were added to the coating resin compositions of the Examples and Comparative Examples by mixing them in Table 3. (Alcon P125 manufactured by Arakawa Chemical Co., Ltd.), aromatic hydrocarbon resin (Crystalex 11 manufactured by Rika Hercules, Inc.)
2.0) and N-oleyl erucamide were blended to prepare an adhesive for heat seal labels. The prepared adhesive was applied to the back surface of the polypropylene label using a bar coater so that the coating amount upon drying was about 3 g / m ² .
This label was pressed onto the adherend shown in Table 3 so that the adhesive surface was in contact with the adherend surface, and a heat seal bar at the temperature shown in Table 3 was applied from the label side at a pressure of 2 kg / cm ² for 2 seconds. Heat sealing was performed by pressing. Table 3 shows the peel strength and cold resistance of the label when heat-sealed at each temperature.

[0022]

[Table 3]

[0023]

Since the composition of the present invention is constituted as described above, it is excellent in pigment dispersibility, cold resistance, cross-linking property, storage stability, etc., and can be used for various plastics, especially polyolefin resins. Because of its excellent adhesion, it can be applied to a wide range of applications as a coating resin composition suitable for coating, bonding or printing on molded products and films of various plastics including polyolefin resins. .

Continuation of the front page (56) References JP-A-63-139953 (JP, A) JP-A-63-51477 (JP, A) JP-A-63-48362 (JP, A) JP-A-61-192743 (JP) JP-A-11-116887 (JP, A) JP-A-11-80649 (JP, A) JP-A-10-176125 (JP, A) JP-A-9-176453 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 151/04 C08F 287/00

Claims (1)

(57) [Claims] 1. A graft copolymer obtained by graft polymerization of a hydrogenated styrene / conjugated diene block copolymer with an α, β-unsaturated dicarboxylic acid and / or an acid anhydride thereof, wherein the graft copolymer Α, β grafted in
25 total of unsaturated dicarboxylic acids and their anhydrides
% Or more of which is half-esterified with a monoalcohol and / or half-amidated with a mono-secondary amine, and the modified graft copolymer (A) is dissolved or dispersed in the modified graft copolymer (A). Solvent (B) obtained,
A coating resin composition comprising, as a main component,