JPH04285618A - Resin composition for coating - Google Patents

Abstract

PURPOSE:To provide a coating composition having excellent storage stability, pigment dispersibility, freeze resistance and crosslinkability and exhibiting excellent adhesivity to various plastics such as polyolefin. CONSTITUTION:The objective resin composition is composed mainly of (A) a modified graft copolymer produced by the graft-polymerization of an alpha,beta-unsaturated dicarboxylic acid and/or its acid anhydride to a hydrogenated styrene/ conjugated diene block copolymer, wherein >=25% of the sum of the grafted dicarboxylic acid and/or its acid anhydride is half-esterified and/or half-amidated and (B) a solvent capable of dissolving or dispersing the component A.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to various plastics, especially polyolefin resins, which can be used when painting, adhering, or printing molded products and films made of various plastics, including polyolefin resins. The present invention relates to a coating resin composition with excellent adhesion.

0002

BACKGROUND OF THE INVENTION In recent years, the use of plastics has been rapidly progressing in various industrial parts such as automobile parts, household electrical parts, and building materials, from the viewpoints of weight reduction, rust prevention, and design freedom. 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 mixed plastics thereof are widely used. However, these plastics, especially polyolefins, are generally difficult to paint, glue, or print, and the plastic surface is usually treated with flame treatment, plasma treatment, corona discharge treatment, etc. before these operations. In reality, they are coated with primer.

0003

However, the above flame treatment, plasma treatment, and corona discharge treatment are insufficient to obtain stable adhesion. Further, as a primer, a primer whose main component is chlorinated polypropylene grafted with maleic anhydride is known, but this primer has problems in cold resistance and pigment dispersibility. Furthermore, α, β
- A primer whose main component is a styrene/conjugated diene block copolymer grafted with an unsaturated dicarboxylic acid and/or its acid anhydride has been proposed (Japanese Patent Application Laid-Open No. 192743/1983, etc.); Stable adhesion can be obtained, and although the cold resistance and pigment dispersibility are improved over the maleic anhydride-grafted chlorinated polyolefin primer, it is not necessarily sufficient, and further improvements are required in terms of storage stability. The current situation is that The present invention is a coating resin composition that has stable adhesion to polyolefin, and when used as a primer, has excellent storage stability, pigment dispersibility, cold resistance, and crosslinking property. In addition, we aim to provide coating resin compositions that can be used in a wider range of applications, such as paints, inks, binders for adhesives, etc., that have stable adhesion to various plastics including polyolefins. It is.

0004

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the present inventors have found that they have good adhesion to various plastics including polyolefins.
In particular, we have discovered a composition that is excellent in storage stability, pigment dispersibility, cold resistance, and crosslinking properties, leading to the present invention. That is, the present invention adds α,β-unsaturated dicarboxylic acid and/or
or a graft copolymer obtained by graft polymerization of an acid anhydride thereof, wherein 25% or more of the total of the grafted α,β-unsaturated dicarboxylic acid and the acid anhydride in the graft copolymer is a monomer. A modified graft copolymer (A) that has been half-esterified with alcohol and/or half amidated with a mono-secondary amine, and a solvent (B) that can dissolve or disperse the modified graft copolymer (A). The present invention provides a coating resin composition containing the present invention as a main component.

[0005] The present invention will be explained in more detail below. [Modified graft copolymer (A)] The modified graft copolymer (A) used in the present invention is a hydrogenated product of a styrene/conjugated diene block copolymer containing an α,β-unsaturated dicarboxylic acid and/or its It is suitably produced by graft polymerizing an acid anhydride and then reacting the graft copolymer with a monoalcohol and/or a monosecondary amine. The modified graft copolymer (A) may also be a half-esterified and/or half-amidated α
, β-unsaturated dicarboxylic acid and/or its acid anhydride alone or α,β-unsaturated dicarboxylic acid and/or its acid anhydride.
Alternatively, it can also be obtained by graft polymerization to a hydrogenated product of styrene/conjugated diene block copolymer together with its acid anhydride. In that case, the graft polymerization is α
, β-unsaturated dicarboxylic acid and/or its acid anhydride under the same conditions as the graft polymerization. Hydrogenated products of styrene/conjugated diene block copolymers include styrene/butadiene diblock copolymers, triblock copolymers, hydrogenated products of tetra or higher multiblock copolymers, and styrene/isoprene diblock copolymers. Examples include hydrogenated products of copolymers, triblock copolymers, and multiblock copolymers. These block copolymers are available, for example, from Shell Chemical Co., Ltd. under the trade name Clayton, and from Asahi Kasei Co., Ltd. under the trade name Tuftec.
Also, one sold under the trade name of SEPTON by Kuraray Co., Ltd. can be suitably used. Regarding the production of a graft copolymer obtained by graft polymerizing α,β-unsaturated dicarboxylic acid and/or its acid anhydride to a hydrogenated styrene/conjugated diene block copolymer, for example, No. 192743, etc., in which α,β-unsaturated dicarboxylic acid and/or its acid anhydride are graft-polymerized to a hydrogenated product of styrene/conjugated diene block copolymer in the presence of a radical polymerization initiator. It can be obtained by Graft polymerization of half ester and/or half amide can also be carried out under similar conditions. The graft polymerization method involves melt-kneading these raw materials using an extruder and heating them at 150℃~
A method of graft polymerization at 300°C or a method of heating and dissolving these in an organic solvent such as toluene, xylene, or chlorobenzene and graft polymerizing at 50°C to 200°C is preferable. The radical polymerization initiator may be any conventional radical initiator, including alkyl peroxides such as ditertiary butyl peroxide and tertiary butyl hydroperoxide, and allyl peroxides such as dicumyl peroxide and cumyl hydroperoxide. , acyl peroxides such as dilauroyl peroxide, aroyl peroxides such as dibenzoyl peroxide, ketone peroxides such as methyl ethyl kent peroxide, peroxy carbonates, and azonitrile such as azobisisobutyronitrile. . Unreacted α,β-unsaturated dicarboxylic acids and/or their acid anhydrides can be easily removed by subjecting the reaction mixture to a vacuum treatment under heating and melting, or by repeatedly washing the reaction mixture with a solvent such as acetone. However, half-esterification and/or
Alternatively, half amidation may be performed. 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 its acid anhydride in the modified graft copolymer (A) is preferably in the range of 0.1 to 10% by weight. When the amount of grafting is less than 0.1%, the adhesion to polyolefin is good, but the adhesion to polar substances such as paints, inks, adhesives, and metals is poor; on the other hand, even when the amount of grafting is over 10%, Further improvement in adhesion to polar substances cannot be expected, and is rather uneconomical.

[Half-esterification and half-amidation] Half-esterification of α,β-unsaturated dicarboxylic acid and/or its acid anhydride grafted onto the graft copolymer with monoalcohol and/or mono-secondary amine As a method for half amidation, a graft copolymer, a monoalcohol and/or a monosecondary amine, and if necessary a catalyst are melt-kneaded using an extruder and reacted at 150 to 300°C, toluene,
A preferred method is to dissolve these raw materials in an organic solvent such as xylene or chlorobenzene and react at 0 to 200°C. The graft copolymer used in the half-esterification and/or half-amidation reaction may be used with or without removal of unreacted α,β-unsaturated dicarboxylic acid and/or its acid anhydride. You may also use In half-esterification and half-amidation reactions, catalysts are not necessarily required, but amines such as triethylamine, tributylamine, and benzyldimethylamine, quaternary ammonium salts such as tetramethylammonium bromide and benzyltrimethylammonium chloride,
Various catalysts such as strong acids such as hydrochloric acid, sulfuric acid, and para-toluenesulfonic acid, and metal oxides such as zinc oxide may be used. However, when using a strong acid, not only half-esterification but also diesterization easily occurs, so care must be taken because half-ester may turn into diester and the half-esterification rate may decrease. There are no particular restrictions on the monoalcohol used for half-esterification, but methanol, ethanol, propanol, butanol, hexanol, octanol, benzyl alcohol,
Examples include phenethyl alcohol, N,N-dimethylaminoethanol, and alkylene oxide adducts thereof. Examples of mono-secondary amines used for half amidation include dimethylamine, diethylamine, dipropylamine, dibutylamine, N-methylcyclohexylamine, and N-methylaniline. The amount of monoalcohol and/or monosecondary amine used is α, β.
- It is necessary to use at least 25 mol% or more of the total unsaturated dicarboxylic acid and/or its acid anhydride. There is no particular restriction on the upper limit, but since these are generally poor solvents for graft copolymers, it is desirable to use them to the extent that solids do not precipitate. 25% or more of the total amount of α,β-unsaturated carboxylic acid and/or its acid anhydride grafted into the modified graft copolymer (A) is half-esterified and/or half-amidated. preferable. If the total amount of half-esterified and/or half-amidated α,β-unsaturated carboxylic acid and/or its acid anhydride is less than 25%, the effect of improving pigment dispersibility, storage stability, etc. is insufficient. It is. In addition,
The half-esterification rate or half-amidation rate refers to the amount of half-ester or half-amide in the total of all the grafted α,β-unsaturated dicarboxylic acids, their acid anhydrides, half-esters or half-amides, and diesters or diamides. It is expressed in mol%.

[Solvent (B)] Half esterification and/
Or as the solvent (B) that can dissolve or disperse the half-amidated modified graft copolymer (A), aromatic hydrocarbons such as toluene, xylene, chlorobenzene, tetralin, mineral spirit, heptane,
Tetrahydrofuran or the like is used as a dissolving solvent. Also, methyl ethyl ketone, methyl isobutyl ketone,
Ethyl acetate, butyl acetate, ethylene glycol dimethyl ether, methyl cellosolve acetate, cellosolve,
Various polar solvents such as ethanol, propanol, and water can be used as a dispersing solvent or a diluent used in combination with the above-mentioned dissolving solvent. There is no particular restriction on the amount of solvent component (B) that can dissolve or disperse component (A), but from the viewpoint of ease of handling and workability, the concentration of component (A) is usually 1 to 60% by weight. , preferably 4 to 50%, (
B) component is 99-40% by weight, preferably 96-50%
Although it is preferable to use it at a concentration of 100%, it is of course possible to use it at a concentration outside this range.

[Additional additives] The composition of the present invention may contain various pigments, dyes, fillers, antioxidants, light stabilizers, ultraviolet absorbers, thixotropic agents, leveling agents, surfactants, blocking agents, etc. Various additives such as inhibitors, slip agents, antistatic agents, and tackifiers; various crosslinking agents such as polyisocyanate compounds, polyepoxides, alkyl etherified melamine formalin resins, and silane coupling agents;
Various coating resins such as chlorinated polypropylene, acrylic resin, unsaturated polyester resin, polyurethane resin, alkyd resin, cellulose resin, vinyl chloride/vinyl acetate copolymer, polyvinyl acetate, and polyamide resin can be added and used. can.

[Application] The composition of the present invention is a primer for improving the adhesion of various plastics such as polyolefins with paints, adhesives, and inks; improving the adhesion of paints, adhesives, and inks for various plastics; additives; binders for various plastic paints; various adhesives such as adhesives for heat sealing between various plastics or between plastics and various metals, adhesives for dry lamination, pressure sensitive adhesives, etc.; or binders for various plastic inks. The present invention provides a coating resin composition that is useful as a coating material 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 target object, but it is usually applied using a spray, brush, coater, printing machine, etc. so that the thickness of the dry film is 0.1μ to 100μ. .

0010

[Example] The present invention will be explained below by giving examples.
The present invention is not limited to these examples. Comparative Example 1 100 g of hydrogenated styrene-butadiene-styrene block copolymer (abbreviated as SEBS) (abbreviated as SEBS) was placed in a glass flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer.
Clayton G-1652 (manufactured by Shell Chemical Co., Ltd.) and 300 g of xylene were charged, the system was replaced with nitrogen and the temperature was raised to 125°C, and then a solution of 10 g of maleic anhydride and 1 g of dicumyl peroxide dissolved in 200 g of xylene was added. The mixture was added dropwise over 10 hours. After the reaction was completed, the system was cooled to around room temperature, and acetone was added to reprecipitate maleated SEBS, followed by filtration and drying to obtain a white powdery grafted resin. Based on 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 this graft resin was heated and dissolved 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 grafted resin obtained in Comparative Example 1
% solution and 2 parts of Etamer were charged into a reactor similar to that used in Comparative Example 1, and a half-esterification reaction was performed by heating and reacting at about 80° C. for 12 hours. After the reaction was completed, 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 the maleic anhydride was half-esterified. The half-esterification rate was determined from the infrared absorption spectrum of (A). Next, a coating resin composition with a solid content of 20% was obtained by heating and dissolving 20 parts of the modified graft copolymer (A) in a mixed solvent of 60 parts of toluene, 10 parts of xylene, and 10 parts of methyl ethyl ketone. Ta.

Comparative Example 2 The hydrogenated styrene butylene block copolymer was replaced with 100 g of hydrogenated styrene isoprene styrene block copolymer (abbreviated as SEPS) (Septon 2002, manufactured by Kuraray Co., Ltd.),
In addition, the synthesis was performed in the same manner as in Comparative Example-1 except that the amount of maleic anhydride was changed to 5 g, and the maleic anhydride content was 2.4%.
A 40% solution of grafted graft resin was obtained.

Example 2 To 100 parts of the graft resin solution obtained in Comparative Example 2, N,
Add 3 parts of N-methylcyclohexylamine, mix thoroughly, and leave at room temperature for 3 days to obtain a modified product with a grafting rate of maleic anhydride of 2.4% and approximately 95% of the maleic anhydride being half-amidated. A 40% solution of grafted resin was obtained.

Example 3 The SEBS used in Comparative Example-1 was added to a resin (Krayton G1726 manufactured by Shell Chemical Co., Ltd.) whose main component is a hydrogenated styrene-butadiene diblock copolymer (abbreviated as SEB).
A graft reaction was carried out in the same manner except that the amount of maleic anhydride 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 grafting rate of maleic anhydride was found to be 5.
．． It was 8%. Next, 30 parts of 1-butanol was added to this reaction solution, and the mixture was further reacted at 100°C to 105°C for 2 hours. After that, the same post-treatment as in Comparative Example 1 was performed,
A 30% solution of a modified graft resin in which the ungrafted maleic anhydride and maleic acid monobutyl ester were removed, the grafting ratio of maleic anhydride was 5.8%, and about 40% of which was half-esterified was prepared. 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 5 parts and the esterification time was 20 minutes.
A 30% solution of a modified graft resin with a grafting rate of maleic anhydride of 5.8% and a half-esterification rate of 13% was obtained.

Example 4 A grafting reaction was carried out in the same manner as in Comparative Example 1 except that 10 parts of maleic anhydride was replaced with 20 parts of monooctyl maleate, and the grafting rate as maleic anhydride was 0.9% and half. A 20% solution of modified resin with an esterification rate of 100% was obtained.

Example 5 30% solution 1 of modified graft resin obtained in Example-3
00 parts, 80% of sodium dioctyl sulfosuccinate
Phase inversion emulsification was performed by dissolving 0.4 parts of the solution and gradually adding 150 parts of distilled water while stirring vigorously. 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 with a modified graft resin concentration of 40%. Ta. Table 1 shows the contents of the coating compositions of Examples 1 to 5 and Comparative Examples 1 to 3, and the storage stability evaluation results.

[0018]

[Table 1]

Application Examples 1 to 7 and Comparative Application Examples 1 to 3
(Application example to primer for painting) A primer for plastic painting was prepared using the coating resins of Examples and Comparative Examples, and the results of evaluating the pigment dispersibility of the primer stock solution are shown in Table 2. In addition, a cross-linking agent may be further added to the primer stock solution, and except for application example 5, a diluting solvent with a xylene/toluene mixing ratio of 1/1 is used in a Ford cup #4 for approximately 15 to
The liquid adjusted to a viscosity of 20 seconds is sprayed onto the coating substrate listed in Table 2 using an air gun so that the dry film thickness is approximately 10μ.In the case of application example 5, the dry film thickness is adjusted using a bar coater. Apply the coating to a thickness of 10μ, and then apply commercially available 2
A test piece for evaluation was prepared by spray painting a liquid type urethane paint to a dry film thickness of about 40 μm and baking it at 80° C. for 1 hour. After this painted test piece was left in a constant temperature room at 23° C. for one week, coating film evaluation was performed. The evaluation results are shown in Table 2.

[0020]

[Table 2]

Application examples 8-12 and comparative application examples 4-
6 (Application example to adhesive for heat-sealable labels) Alicyclic petroleum resin (Alcon P125 manufactured by Arakawa Chemical Co., Ltd.) and aromatic carbonization were added to the coating resin compositions of Examples and Comparative Examples in the formulations shown in Table 3. A hydrogen resin (Crystalex 112.0 manufactured by Rika Hercules Co., Ltd.) and N-oleyl erucamide were blended to prepare an adhesive for heat seal labels. The prepared adhesive was applied to the back side of a polypropylene label using a bar coater so that the dry coating amount was about 3 g/m2. Press this label onto the adherend listed in Table 3 so that the adhesive side is in contact with the adherend surface, and apply a heat seal bar at the temperature listed in Table 3 from the label side to the adherend for 2 seconds at a pressure of 2 kg/cm2.
Heat sealed by pressing for seconds. Table 3 shows the results of the peel strength and cold/heat resistance of the label when heat-sealed at each temperature.

[0022]

[Table 3]

[0023]

Effects of the Invention Since the composition of the present invention has the above-mentioned structure, it is excellent in pigment dispersibility, cold resistance, crosslinking property, storage stability, etc., and is suitable for various plastics, especially polyolefin resins. Because of its excellent adhesion to polyolefin resins, it can be used in a wide range of applications as a coating resin composition suitable for painting, adhesion, or printing on various plastic molded products and films, including polyolefin resins. .

Claims (1)

[Claims] Claim 1: A hydrogenated product of styrene/conjugated diene block copolymer containing α,β-unsaturated dicarboxylic acid and/or
or a graft copolymer obtained by graft polymerizing an acid anhydride thereof, wherein the grafted α,
2 of the total of β-unsaturated dicarboxylic acids and their acid anhydrides
A modified graft copolymer (A) in which 5% or more of the modified graft copolymer (A) has been half-esterified with a monoalcohol and/or half-amidated with a mono-secondary amine, and the modified graft copolymer (A) is dissolved or dispersed. A coating resin composition containing a solvent (B) as a main component.