JP2014095035A - Resin composition, coating material using the same, and product coated by the coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition having excellent adhesion property to a difficult-to-attach substrate such as polyamide, further having no remarkable reduction of adhesive property even when immersed into warm water, and capable of forming a coating film having high solvent resistance, and to provide a coating material using the resin composition and a product coated by the coating material.SOLUTION: A resin composition containing a polymer (A) obtained by polymerizing a monomer mixture containing a monomer having a secondary hydroxyl group (a1) of 3 to 22 mass% and a monomer having a phosphate group (a2) of 0.01 to 0.8 mass% is used. Further preferably, the resin composition using 2-hydroxypropyl (meth)acrylate as the monomer (a1) and 2-(meth)acryloyloxyethyl acid phosphate as the monomer (a2) is used.

Description

  The problem to be solved by the present invention is that the present invention has excellent adhesion even to difficult-to-adhere substrates such as polyamide, and there is no significant decrease in adhesion even when immersed in warm water, And it is related with the resin composition which can form the coating film which has high solvent resistance. The present invention also relates to a paint using the resin composition and an article coated with the paint.

  Conventionally, acrylic resins are widely used in applications such as paints, inks, adhesives, and synthetic leather because of their excellent weather resistance, flexibility, strength, adhesiveness, and the like. In particular, in paint applications, acrylics that match each required performance as the base resin of paints for coating various base materials (for example, metal, wood, paper, plastic) in the fields of automobiles, home appliances, building materials, etc. Resin has been developed.

  On the other hand, as plastic molded products, for example, those made of a resin such as acrylonitrile-butadiene-styrene copolymer (ABS resin), polycarbonate (PC resin), polystyrene (PS resin), etc. are easy to cost and mold. So, it is used a lot. In addition, thinning has been promoted in order to reduce the weight required for plastic molded products, but since mechanical strength is reduced due to thinning, polyamide and glass fiber-containing polyamide with higher mechanical strength are used as materials. Plastic molded products are used.

  However, since polyamide is significantly different in polarity from other resins, even an acrylic resin capable of forming a coating film that exhibits excellent adhesion to other resins is sufficient for polyamide. There was a problem that adhesiveness could not be expressed.

  As what improves the adhesiveness with respect to this polyamide, the acrylic resin composition for coating materials containing the acrylic resin obtained by superposing | polymerizing cyclohexyl acrylate is proposed (for example, refer patent document 1). However, although the coating film of the coating material using this acrylic resin composition for coating material has improved adhesion to polyamide, it has a problem of poor solvent resistance. Therefore, a coating material that has excellent adhesion without being affected by the type of material of the base material, in particular, has excellent adhesion to polyamide, and can form a coating film having high solvent resistance. Was demanded.

JP 2007-302835 A

  The problem to be solved by the present invention is that it has excellent adhesion to difficult-to-adhere substrates such as polyamide, and has no significant decrease in adhesion even when immersed in warm water, and has high solvent resistance It is providing the resin composition which can form the coating film which has this. Moreover, it is providing the coating material using this resin composition, and the article coated with this coating material.

  As a result of earnest research to solve the above problems, the present inventors polymerized a monomer mixture containing a monomer having a secondary hydroxyl group and a monomer having a phosphate group at a specific ratio. The resin composition containing the obtained polymer has excellent adhesion to difficult-to-adhere base materials such as polyamide, and further, there is no significant decrease in adhesion even when immersed in warm water, and it is high The inventors have found that a coating film having solvent resistance can be formed, and have completed the invention.

  That is, the present invention provides a monomer mixture containing 3 to 22% by mass of a monomer having a secondary hydroxyl group (a1) and 0.01 to 0.8% by mass of a monomer having a phosphate group (a2). The present invention relates to a resin composition comprising a polymer (A) obtained by polymerization. The present invention also relates to a paint using the composition and an article coated with the paint.

  The resin composition of the present invention has excellent adhesion to difficult-to-adhere substrates such as polyamide, glass fiber-containing polyamide, and carbon fiber-containing polyamide, and further drastically reduces adhesion even when immersed in warm water. And a coating film having high solvent resistance can be formed. Therefore, it is very useful as a paint for coating various articles such as plastic molded products made of polyamide, glass fiber-containing polyamide, carbon fiber-containing polyamide, or the like.

  The resin composition of the present invention is a monomer containing 3 to 22% by mass of a monomer having a secondary hydroxyl group (a1) and 0.01 to 0.8% by mass of a monomer having a phosphate group (a2). It contains a polymer (A) obtained by polymerizing the mixture.

  The monomer (a1) is a monomer having a secondary hydroxyl group, and as the secondary hydroxyl group, a hydroxyl group bonded to a carbon atom serving as a branching point of the branched alkyl group, an alicyclic alkyl group, or the like. Examples thereof include a hydroxyl group bonded to the alicyclic portion of the group. Specific examples of the monomer (a1) include 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and hydroxycyclohexyl (meth) acrylate. Among these, 2-hydroxypropyl (meth) acrylate is preferable because adhesion to the base material can be further improved. Moreover, these monomers (a1) can be used alone or in combination of two or more.

  The monomer (a2) is a monomer having a phosphate group. Specific examples thereof include 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxyethyl acid diphenyl phosphate, In addition to 2- (meth) acryloyloxyethyl acid dialkyl phosphate, allylbenzylmethylphenylphosphonium bromide, allylbenzylethylphenylphosphonium bromide, triphenylvinylphosphonium bromide, allyltriphenylphosphonium bromide, trivinylphosphine, dipropylvinylphosphine , Methyl vinyl phenyl phosphine, diphenyl vinyl phosphine, allyl diphenyl phosphine, diethyl vinyl phosphine oxide, dipropyl vinyl phosphine ox , Divinylphenylphosphine oxide, ethylvinylphenylphosphine oxide, dibutylvinylphosphine oxide, diallylphenylphosphine oxide, diphenylvinylphosphine oxide, diallylphenylphosphonate, vinylphosphonic dichloride, diethylvinylphosphonate, allyldichlorophosphite, diallylphosphite, Examples include triallyl phosphite and triallyl phosphate. Among these, 2- (meth) acryloyloxyethyl acid phosphate is preferable because adhesion to the substrate can be further improved. Moreover, these monomers (a1) can be used alone or in combination of two or more.

  In the present invention, “(meth) acrylate” refers to one or both of methacrylate and acrylate, “(meth) acrylamide” refers to one or both of methacrylamide and acrylamide, and “(meth) acryloyl”. "Means one or both of methacryloyl and acryloyl," (meth) acrylonitrile "means one or both of methacrylonitrile and acrylonitrile," (meth) acrylic acid "means methacrylic acid and acrylic acid Or one of both.

  The polymer (A) is obtained by polymerizing the monomer (a1) and the monomer (a2) as essential monomer components, but other monomers other than these monomers ( a3) is used. Examples of such other monomer (a3) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 4 -(Meth) acrylic acid ester compounds such as hydroxybutyl (meth) acrylate; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) A N, N-dialkylaminoalkyl (meth) acrylate such as relate, N, N-diethylaminopropyl (meth) acrylate; N- (N, N-dimethylaminoethyl) (meth) acrylamide, N- (N, N-diethylamino) N- (N, N-dialkylaminoalkyl) such as ethyl) (meth) acrylamide, N- (N, N-dimethylaminopropyl) (meth) acrylamide, N- (N, N-diethylaminopropyl) (meth) acrylamide (Meth) acrylamide; t-butylaminoalkyl (meth) acrylate such as t-butylaminoethyl (meth) acrylate and t-butylaminopropyl (meth) acrylate; aziridinylethyl (meth) acrylate, pyrrolidinylethyl ( (Meth) acrylate, piperidinylethyl Dialkyl ester compounds of unsaturated dibasic acids such as alkyl (meth) acrylate having a cyclic amino group such as (meth) acrylate, dimethyl fumarate, dibutyl fumarate, dimethyl itaconate; (meth) acrylic acid, monobutyl Vinyl monomers having a carboxyl group such as malate, monobutyl fumarate, crotonic acid, maleic acid, fumaric acid and itaconic acid; vinyl monomers having an acid anhydride group such as maleic anhydride and itaconic anhydride; Vinyl monomers having a cyano group such as (meth) acrylonitrile; vinyl monomers having a sulfonic acid group such as p-styrenesulfonic acid and 2-acrylamido-2-methyl-propanesulfonic acid; vinyl acetate, vinyl benzoate, “Veoba” (a vinyl ester made by Ciel of the Netherlands), etc. Tellurium compound; “Biscoat 8F, 8FM, 3F or 3FM” (fluorine-containing (meth) acrylic monomer manufactured by Osaka Organic Chemical Co., Ltd.), perfluorocyclohexyl (meth) acrylate, di-perfluorocyclohexyl fumarate, N-iso- Vinyl monomers having a fluorinated alkyl group such as propylperfluorooctanesulfonamidoethyl (meth) acrylate; halogenated olefins such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene; styrene, Examples thereof include aromatic vinyl monomers such as α-methylstyrene, p- (t-butyl) styrene, vinyltoluene and the like. Moreover, these monomers (a3) can be used alone or in combination of two or more.

  The ratio of the monomer (a1) in the monomer mixture used as the raw material for the polymer (A) is 5 to 20% by mass, but the solvent resistance can be further improved, so 3 to 22% by mass. The range of 5-20 mass% is more preferable, The range of 7-15 mass% is further more preferable. Moreover, although the ratio of the said monomer (a2) is 0.01-0.8 mass%, since the adhesiveness can be improved more, the range of 0.05-0.5 mass% is preferable.

  The polymer (A) can be produced by a known polymerization method using the monomer (a1) and the monomer (a2), and, if necessary, other monomers (a3) as raw materials. Although it can be performed, the solution radical polymerization method is preferred because it is the simplest.

  The solution radical polymerization method is a method in which each monomer as a raw material is dissolved in a solvent and a polymerization reaction is performed in the presence of a polymerization initiator. Examples of the solvent that can be used in this case include hydrocarbon solvents such as toluene, xylene, cyclohexane, n-hexane, and octane; methanol, ethanol, iso-propanol, n-butanol, iso-butanol, sec-butanol. Alcohol solvents such as ethylene glycol monomethyl ether; ester solvents such as methyl acetate, ethyl acetate, acetic acid-n-butyl, acetic acid-isobutyl, and amyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone Is mentioned. These solvents can be used alone or in combination of two or more.

  Examples of the polymerization initiator include ketone peroxide compounds such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (t-butylperoxy) -3, 3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (4,4-di -T-butylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-amylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-hexylperoxycyclohexyl) Propane, 2,2-bis (4,4-di-t-octylperoxycyclohexyl) propane, Peroxyketal compounds such as 1,2-bis (4,4-dicumylperoxycyclohexyl) propane; hydroperoxide compounds such as cumene hydroperoxide and 2,5-dimethylhexane-2,5-dihydroperoxide; 1,3-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diisopropylbenzene peroxide, t-butylcumyl peroxide, etc. Dialkyl peroxide compounds; diacyl peroxide compounds such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide; peroxides such as bis (t-butylcyclohexyl) peroxydicarbonate Carbonate compounds; organic peroxides such as peroxyester compounds such as t-butylperoxybenzoate and 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, and 2,2′-azobisisobutyrate Examples include azo compounds such as rhonitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), and the like.

  Further, together with the polymerization initiator, if necessary, a chain transfer agent such as lauryl mercaptan, octyl mercaptan, 2-mercaptoethanol, octyl thioglycolate, 3-mercaptopropionic acid, α-methylstyrene dimer as a molecular weight regulator. Can also be used.

  The glass transition temperature (hereinafter abbreviated as “Tg”) of the polymer (A) is preferably in the range of 0 to 60 ° C. because it has better adhesion to the substrate. The range of 55 ° C is more preferable, and the range of 10 to 50 ° C is more preferable. In addition, Tg in this invention is calculated | required by following formula (1).

Tg ⁻¹ = ΣXi · Tgi ⁻¹ (K) (1)
It is assumed that n monomer components of i = 1 to n are copolymerized. Xi is the mass fraction of the i-th monomer, and Tgi is the Tg of the homopolymer of the i-th monomer. The Tg of the monomer homopolymer was determined by Polymer Handbook (4th Edition) J. MoI. Brandrup, E .; H. Immergut, E .; A. Values described by Grulke (Wiley Interscience) were used.

  The coating material of this invention contains the hardening | curing agent (B) containing said resin composition of this invention, and polyisocyanate. Examples of the polyisocyanate include 1,4-tetramethylene diisocyanate, ethyl (2,6-diisocyanate) hexanoate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,2,4- Or aliphatic diisocyanates such as 2,4,4-trimethylhexamethylene diisocyanate; 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 2-isocyanatoethyl (2 , 6-diisocyanato) hexanoate; 1,3-bis (isocyanatomethylcyclohexane), 1,4-bis (isocyanatomethylcyclohexane), 1,3-diisocyanatocyclohexane, 1, 4-di Sodium cyclohexane, 3,5,5-trimethyl (3-isocyanatomethyl) cyclohexyl isocyanate, dicyclohexylmethane-4,4'-diisocyanate, 2,5-diisocyanate methyl norbornane, 2,6-diisocyanatomethyl norbornane Alicyclic diisocyanates such as 2,5-diisocyanatomethyl-2-isocyanate propyl norbornane, 2,6-diisocyanatomethyl-2-isocyanate propyl norbornane; m- Aralkylene diisocyanates such as xylylene diisocyanate, α, α, α′α′-tetramethyl-m-xylylene diisocyanate; m- or p-phenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-di Isocyanate, diphenylmethane-4,4′-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4′-diisocyanate, 4,4′-diisocyanate-3,3′-dimethyldiphenyl, 3-methyl-diphenylmethane Aromatic diisocyanates such as -4,4'-diisocyanate and diphenyl ether-4,4'-diisocyanate; aromatic triisocyanates such as triphenylmethane triisocyanate and tris (isocyanatophenyl) thiophosphate; A polyisocyanate having a uretdione structure obtained by cyclizing and dimerizing isocyanate groups; obtained by cyclizing and trimerizing the isocyanate groups of the diisocyanate or triisocyanate. A polyisocyanate having an isocyanurate structure; a polyisocyanate having a burette structure obtained by reacting the diisocyanate or triisocyanate with water; an oxadiazine trione obtained by reacting the diisocyanate or triisocyanate with carbon dioxide Examples thereof include polyisocyanates having a structure; polyisocyanates having an allophanate structure. Among these, a polyisocyanate having an isocyanurate structure in which hexamethylene diisocyanate or the like is cyclized and trimerized is preferable because a dense crosslinked coating film can be formed and the solvent resistance of the cured coating film can be further improved. These polyisocyanates can be used alone or in combination of two or more.

  The amount of the curing agent (B) is such that the solvent resistance of the coating film of the present invention is further improved, so that the hydroxyl group (OH) of the polymer (A) and the curing agent (B) are included. The equivalent ratio [(NCO) / (OH)] with the isocyanate group (NCO) of the polyisocyanate contained is preferably in the range of 0.5 to 2, and in an amount in the range of 0.8 to 1.5. It is preferable.

  Furthermore, the paint of the present invention includes organic pigments, inorganic pigments, anti-splitting agents (pigment dispersants), antistatic agents, antifoaming agents, viscosity modifiers (flow modifiers), light-resistant stabilizers, and weathering stabilizers. , Various additives such as heat stabilizers, UV absorbers, antioxidants, leveling agents; fiber derivatives such as nitrocellulose and cellulose acetate butyrate; chlorinated polyethylene, chlorinated polypropylene, petroleum resins, chlorinated rubber, etc. Resin can be added.

  Since the paint of the present invention has excellent adhesion to a base material and high solvent resistance, the paint surface is protected by coating the paint on the surface of various articles. be able to. Moreover, the coating material of this invention can be used also as a primer agent before apply | coating a finishing coating material. Examples of articles that can be coated with the paint of the present invention include housings for home appliances such as televisions, refrigerators, washing machines, and air conditioners; housings for electronic devices such as personal computers, smartphones, mobile phones, digital cameras, and game machines. Body: Housing for OA equipment such as printers, facsimiles, etc .; Various plastic parts such as various parts used for interior materials of various vehicles such as automobiles and railway vehicles; Woodwork materials such as furniture, artificial and synthetic leather; FRP bathtubs It is done. In addition, interior and exterior materials for buildings such as outer walls, roofs, glass, and decorative panels; civil engineering members such as soundproof walls and drainage grooves; galvanized steel sheets used for household appliances, industrial machinery, automotive parts, and aluminum-zinc Metal members such as plated steel plates such as alloy steel plates, aluminum plates, aluminum alloy plates, electromagnetic steel plates, copper plates, and stainless steel plates are also included. Among these articles, it is preferable to use the coating material of the present invention for plastic molded articles made of polyamide, glass fiber-containing polyamide, carbon fiber-containing polyamide, etc., which are difficult to adhere.

  The coating method of the paint of the present invention varies depending on the application. For example, gravure coater, roll coater, comma coater, knife coater, air knife coater, curtain coater, kiss coater, shower coater, wheeler coater, spin coater, dipping, screen printing , Spray, applicator, bar coater and the like. In addition, examples of the method for forming a cured coating film after applying the paint of the present invention include a method of heating and drying in the range of room temperature to about 80 ° C.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

Example 1
A reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube was charged with 70 parts by mass of xylene, heated to 90 ° C. in a nitrogen atmosphere, 10 parts by mass of styrene, 50 parts by mass of methyl methacrylate, Mixture of dodecyl methacrylate and tridecyl methacrylate ("Blemmer SLMA" manufactured by NOF Corporation), 34.4 parts by mass, 5.5 parts by mass of 2-hydroxypropyl methacrylate, 2-methacryloyloxyethyl acid phosphate (manufactured by Kyoeisha Chemical Co., Ltd.) "Light ester P-1M") 0.2 parts by mass, 2,2'-azobis (2-methylbutyronitrile) (hereinafter abbreviated as "ABN-E") 1 part by mass and xylene 5 parts by mass The resulting mixture was added dropwise over 4 hours. After completion of dropping, the mixture was maintained at 90 ° C. for 2 hours, and then a mixture composed of 0.2 parts by mass of ABN-E and 30 parts by mass of n-butanol was added dropwise over 1 hour. Subsequently, after hold | maintaining at 90 degreeC for 12 hours, the 45 mass% solution of the polymer (A-1) was obtained by adding n-butanol. In addition, let the solution of this polymer (A-1) be a resin composition (1). Moreover, Tg of the polymer (A-1) was 19 ° C.

[Preparation of paint]
100 parts by mass of the resin composition (1) (polymer (A-1) solution) obtained in Example 1 and a curing agent (“Bernock DN-980” manufactured by DIC Corporation), non-volatile content of polyisocyanate 75 4.8 parts by mass of (mass% solution) was uniformly mixed. The mixing ratio of the resin composition (1) and the curing agent was such that the hydroxyl group equivalent of the resin composition (1) and the isocyanate group equivalent of the curing agent were 1: 1. Next, a mixed solvent (toluene / xylene / butyl acetate / propylene glycol methyl ether acetate = 40/20/30) so that the viscosity is 10 to 11 seconds (23 ° C.) by “Viscosity Cup NK-2” manufactured by Anest Iwata Co., Ltd. / 10 (mass ratio)) to prepare a paint.

[Preparation of coating film for evaluation]
The paint obtained above is spray-coated on a polyamide 6 resin plate (Mitsubishi Gas Chemical Co., Ltd., plate thickness 3 mm) so that the dry coating thickness is 15 μm, and heated at 80 ° C. for 30 minutes in a dryer. After drying, the coating film for evaluation was produced by drying at 25 ° C. for 1 day.

[Evaluation of adhesion]
The coating film for evaluation obtained above was measured based on the cross cut test method of JIS K-5400. A 1 mm wide cut is made on the cured coating film with a cutter, the number of grids is 100, cellophane tape is applied so as to cover all grids, and they are peeled off quickly to adhere and remain. From the number, the adhesion was evaluated according to the following criteria.
A: 96-100 pieces B: 91-95 pieces C: 60-90 pieces D: 31-59 pieces E: 30 pieces or less

[Evaluation of adhesion after immersion in hot water]
The evaluation coating film obtained above was immersed in 60 ° C. warm water for 5 hours. Subsequently, after taking out from warm water and wiping off moisture well, the adhesiveness after warm water immersion was evaluated similarly to said method.

[Evaluation of solvent resistance]
The same part of the surface of the coating film for evaluation obtained above was rubbed 300 times back and forth with a felt soaked in ethanol. Next, the state of the coating film before rubbing and after rubbing was confirmed by touch and visual observation, and the solvent resistance was evaluated according to the following criteria.
A: There is almost no change in the coating film.
B: The underlying resin plate is not visible, but the coating is thin.
C: There is a portion where the coating film has fallen off, and the underlying resin plate is visible.

(Examples 2 to 5)
Except having changed the usage-amount of each monomer into the quantity shown in Table 1, it operated similarly to Example 1 and obtained the 45 mass% solution of polymer (A-2)-(A-5). . In addition, let the solution of this polymer (A-2)-(A-5) be resin composition (2)-(5), respectively. Moreover, after preparing a coating material using resin composition (2)-(5) similarly to Example 1, the coating film for evaluation was produced and adhesiveness, the adhesiveness after a hot water test, and solvent resistance evaluation were carried out. .

(Comparative Examples 1-7)
A 45 mass% solution of the polymers (R-1) to (R-5) was obtained in the same manner as in Example 1 except that the amount of each monomer used was changed to the amount shown in Table 2. . In addition, let the solution of this polymer (R-1)-(R-5) be resin composition (R1)-(R5), respectively. Moreover, after preparing a coating material using resin composition (R1)-(R5) similarly to Example 1, the coating film for evaluation was produced and adhesiveness, the adhesiveness after a hot water test, and solvent resistance evaluation were carried out. . In Comparative Examples 2 and 5, the adhesion before warm water immersion was very low, so the adhesion after warm water immersion was not evaluated.

  Tables 1 and 2 show the monomer composition of each polymer, the solvent composition in each resin composition, and the evaluation results of the storage stability of each resin composition.

The abbreviations in Tables 1 and 2 are as follows.
St: Styrene MMA: Methyl methacrylate SLMA: Mixture of dodecyl methacrylate and tridecyl methacrylate (“Blemmer SLMA” manufactured by NOF Corporation)
nBA: butyl acrylate HEPA: 2-hydroxypropyl methacrylate (monomer having secondary hydroxyl group)
HEMA: 2-hydroxyethyl methacrylate (monomer having a primary hydroxyl group)
L-P1M: 2-methacryloyloxyethyl acid phosphate (“Eye ester P-1M” manufactured by Kyoeisha Chemical Co., Ltd.)

  From the evaluation results of Examples 1 to 5 shown in Table 1, it was confirmed that the coating films of the resin compositions (1) to (5) of the present invention have excellent adhesion. It was also confirmed that there was no significant decrease in adhesion even after the coating film was immersed in warm water. Furthermore, it was learned that the coating films of the resin compositions (1) to (5) of the present invention have high solvent resistance.

  On the other hand, from the evaluation results of Comparative Examples 1 to 5 shown in Table 2, the following was confirmed.

  Comparative Example 1 is an example of a resin composition produced using a monomer having a primary hydroxyl group instead of the monomer having a secondary hydroxyl group (a1). It was confirmed that the adhesion was insufficient.

  Although the comparative example 2 is an example of the resin composition manufactured without using the monomer (a2) which has a phosphate group, it was confirmed that the adhesiveness of the coating film is inadequate.

  Comparative Example 3 is an example of a resin composition produced using 1% by mass of the phosphoric acid group-containing monomer (a2) exceeding 0.8% by mass, which is the upper limit defined in the present invention. It was confirmed that the adhesion of the coating film was slightly insufficient.

  Comparative Example 4 is an example of a resin composition produced using 1% by mass of less than 3% by mass of the monomer (a1) having a secondary hydroxyl group as defined in the present invention. It was confirmed that the solvent resistance of the film was insufficient.

  Comparative Example 5 is an example of a resin composition produced using 25% by mass of the monomer (a1) having a secondary hydroxyl group, which exceeds the upper limit of 22% by mass defined in the present invention. It was confirmed that the adhesiveness of was insufficient.

Claims (6)

  Obtained by polymerizing a monomer mixture containing 3 to 22% by mass of a monomer having a secondary hydroxyl group (a1) and 0.01 to 0.8% by mass of a monomer having a phosphate group (a2) A resin composition comprising a polymer (A).   The resin composition according to claim 1, wherein the monomer (a1) is 2-hydroxypropyl (meth) acrylate.   The resin composition according to claim 1 or 2, wherein the monomer (a2) is 2- (meth) acryloyloxyethyl acid phosphate.   The resin composition according to any one of claims 1 to 3, wherein a glass transition temperature of the polymer (A) is in a range of 0 to 60 ° C.   A paint comprising the resin composition according to any one of claims 1 to 4 and a curing agent (B) containing polyisocyanate.   An article coated with the paint according to claim 5.