Resin composition

Abstract

To provide a resin composition which has high adhesion to various substrates and is excellent in water resistance.SOLUTION: The resin composition of the present invention contains a copolymer (P) obtained by radically polymerizing at least one ethylenically unsaturated monomer (A) having a functional group (a) represented by the following formula (I) and at least one unsaturated monomer (B) different from the monomer (A). The content of the functional group (a) in the copolymer (P) is 0.02 mmol / g or more and 0.5 mmol / g or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition. [Background technology]

[0002] Functional polymers have a wide range of applications depending on their properties, and research into functional polymers with unprecedented functionality is actively underway. Acrylic resins, in particular, can be given a variety of functions by combining monomers. Generally, acrylic resins do not have the high adhesion to metal surfaces that epoxy resins do. However, as a means of improving adhesion to metal surfaces, development is underway to introduce carboxylic acid or phosphate groups into acrylic resins, for example.

[0003] For example, Patent Document 1 discloses a coating composition containing an acrylic resin (A) having a specific hydroxyl value and weight-average molecular weight, an amino resin (B), and an acrylic resin (C) having a phosphate group and a hydrogenated epoxy skeleton and having a specific acid value and weight-average molecular weight. Patent Document 1 also describes that by blending the above-mentioned resins (A) to (C), a coating film can be obtained that exhibits good adhesion to various metal materials including aluminum and also has excellent weather resistance and corrosion resistance.

[0004] Patent Document 2 discloses a binder resin containing a (meth)acrylic polymer essentially composed of 60% by weight or more of carboxylic acid ester monomer units having an alkyl group with 4 to 18 carbon atoms and carboxylic acid ester monomer units having an aminoalkyl group. Patent Document 2 also describes that by using the binder resin in a primer or coating material, a coating film having excellent adhesion to various substrates, paints, etc. can be formed.

[0005] Meanwhile, it has recently been discovered that the adhesive substances secreted by the marine sessile organism Mytilus edulis contain large amounts of catechol groups (see Non-Patent Document 1), and research is underway into their application to coatings or adhesives. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-012814 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-350606 [Non-patent literature]

[0007] [Non-Patent Document 1] Masanobu Naito, Functional materials mimicking marine sessile organisms, J.Jpn.Soc.Colour.,87[1],13-18,2014 Summary of the Invention [Problem to be solved by the invention]

[0008] The resins described in the above patent documents, in which a carboxylic acid group or a phosphate group is introduced into an acrylic resin, are not sufficient to achieve adhesive strength comparable to that of epoxy resins to various substrates such as metals, metal oxides, mortar, and concrete, and there is still room for improvement. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resin composition that has high adhesion to various substrates and excellent water resistance. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by introducing a catechol group and a substituent having a structure similar thereto into an acrylic resin in a specific ratio, thereby completing the present invention.

[0010] That is, the present invention provides a resin composition containing a copolymer (P) obtained by radical polymerization of an ethylenically unsaturated monomer (A) having a functional group (a) represented by the following formula (I) and at least one unsaturated monomer (B) different from the ethylenically unsaturated monomer (A), wherein the content of the functional group (a) in the copolymer (P) is 0.02 mmol / g or more and 0.5 mmol / g or less:

[0011] [ka] (In formula (I), X is a hydrogen atom or a hydroxyl group.)

[0012] The functional group (a) is preferably a functional group represented by the following formula (II).

[0013] [ka]

[0014] The weight average molecular weight Mw of the copolymer (P) is preferably 10,000 or more and 300,000 or less. [Effects of the Invention]

[0015] According to the present invention, a resin composition having high adhesion to various substrates and excellent water resistance can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the present invention will be described below.

[0017] [Resin composition] The resin composition of the present invention is a resin composition containing a copolymer (P) obtained by radical polymerization of an ethylenically unsaturated monomer (A) having at least one functional group (a) represented by the following formula (I) and at least one unsaturated monomer (B) different from the ethylenically unsaturated monomer (A), wherein the content of the functional group (a) in the copolymer (P) is 0.02 mmol / g or more and 0.5 mmol / g or less: The resin composition will be described in detail below.

[0018] <Ethylenically unsaturated monomer (A) having functional group (a)> The ethylenically unsaturated monomer (A) has a functional group (a) represented by the following formula (I).

[0019] [ka]

[0020] In formula (I), X is a hydrogen atom or a hydroxyl group.

[0021] In the functional group (a), R in formula (I) is not particularly limited and is, for example, an organic group having 1 to 20 carbon atoms, which may contain a functional group such as a carbonyl group or a hydroxy group.

[0022] Examples of the functional group (a) include a catechol group (a1) in which X in formula (I) is a hydrogen atom, and a pyrogallol group (a2) in which X is a hydroxyl group. The functional group (a) preferably has a pyrogallol group (a2) because this further improves adhesion to various substrates. The pyrogallol group (a2) is represented by the following formula (II):

[0023] [ka]

[0024] In the present invention, the content of functional group (a) contained in copolymer (P) is 0.02 mmol / g or more and 0.5 mmol / g or less. When the content of functional group (a) is 0.02 mmol / g or more, excellent adhesion to various substrates is achieved. Furthermore, when the content of functional group (a) is 0.5 mmol / g or less, excellent water resistance of the coating film is achieved.

[0025] <Unsaturated Monomer (B)> Specific examples of the unsaturated monomer (B) include vinyl monomers containing functional groups, such as (meth)acrylic acid esters, aromatic vinyl compounds, vinyl cyanide compounds, carboxyl group-containing vinyl compounds, hydroxyl group-containing vinyl compounds, glycidyl group-containing vinyl compounds, and vinyl compounds having secondary and / or tertiary amide groups.

[0026] Specific examples of (meth)acrylic acid esters are not particularly limited, and include, for example, (meth)acrylic acid alkyl esters having an alkyl group with 1 to 50 carbon atoms, and (poly)oxyethylene di(meth)acrylates having an ethylene oxide group with 1 to 100 carbon atoms.

[0027] Specific examples of the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 50 carbon atoms are not particularly limited, and include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, cyclohexyl (meth)acrylate, lauryl (meth)acrylate, and dodecyl (meth)acrylate.

[0028] Specific examples of (poly)oxyethylene di(meth)acrylates having an ethylene oxide group having 1 to 100 carbon atoms include, but are not limited to, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, diethylene glycol methoxy(meth)acrylate, and tetraethylene glycol di(meth)acrylate.

[0029] Specific examples of aromatic vinyl compounds include, but are not limited to, styrene, α-methylstyrene, p-tert-butylstyrene, chlorostyrene, vinyltoluene, and the like.

[0030] Specific examples of the vinyl cyanide compound include, but are not limited to, acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, and the like.

[0031] Specific examples of the carboxyl group-containing vinyl compound include, but are not limited to, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, and half esters of dibasic acids such as itaconic acid, maleic acid, and fumaric acid.

[0032] Specific examples of hydroxyl group-containing vinyl compounds are not particularly limited, and include, for example, hydroxyalkyl esters of (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate, allyl alcohol, (poly)oxyethylene mono(meth)acrylate having 1 to 100 ethylene oxide groups; (poly)oxypropylene mono(meth)acrylate having 1 to 100 propylene oxide groups; and further, "Placcel FM, FA Monomer" (trade name of caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.) and other hydroxyalkyl esters of α,β-ethylenically unsaturated carboxylic acids.

[0033] Specific examples of the (poly)oxyethylene (meth)acrylate having 1 to 100 ethylene oxide groups are not particularly limited, and include, for example, ethylene glycol (meth)acrylate, ethylene glycol methoxy(meth)acrylate, diethylene glycol (meth)acrylate, diethylene glycol methoxy(meth)acrylate, tetraethylene glycol (meth)acrylate, and tetraethylene glycol methoxy(meth)acrylate.

[0034] Specific examples of the (poly)oxypropylene (meth)acrylate having 1 to 100 propylene oxide groups are not particularly limited, and include, for example, propylene glycol (meth)acrylate, propylene glycol methoxy(meth)acrylate, dipropylene glycol (meth)acrylate, dipropylene glycol methoxy(meth)acrylate, tetrapropylene glycol (meth)acrylate, and tetrapropylene glycol methoxy(meth)acrylate.

[0035] Specific examples of the glycidyl group-containing vinyl compound are not particularly limited, and include, for example, glycidyl (meth)acrylate, allyl glycidyl ether, and allyl dimethyl glycidyl ether.

[0036] Specific examples of vinyl compounds having secondary and / or tertiary amide groups are not particularly limited, and include, for example, N-alkyl-substituted (meth)acrylamides, N-alkylene-substituted (meth)acrylamides, and the like.

[0037] Specific examples of N-alkyl substituted (meth)acrylamides are not particularly limited, and include, for example, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethylacrylamide, N-methyl-N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, Nn-propyl(meth)acrylamide, N-methyl-Nn-propyl(meth)acrylamide, N-methyl-N-isopropyl(meth)acrylamide, N-(meth)acryloylpyrrolidine, N-(meth)acryloylpiperidine, N-acryloylhexahydroazepine, N-(meth)acryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, N,N'-methylenebis(meth)acrylamide, N-vinylacetamide, diacetone(meth)acrylamide, and N-methylol(meth)acrylamide.

[0038] Specific examples of vinyl monomers other than those mentioned above include (meth)acrylamide, olefins such as ethylene, propylene, and isobutylene; dienes such as butadiene; haloolefins such as vinyl chloride, vinylidene chloride vinyl fluoride, tetrafluoroethylene, and chlorotrifluoroethylene; vinyl carboxylic acid esters such as vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl benzoate, vinyl p-tert-butylbenzoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versatate, and vinyl laurate; isopropenyl carboxylic acid esters such as isopropenyl acetate and isopropenyl propionate; ethyl vinyl ether, isobutyl vinyl ether, Examples of suitable vinyl ethers include vinyl ethers such as methyl ether and cyclohexyl vinyl ether; aromatic vinyl compounds such as styrene and vinyl toluene; allyl esters such as allyl acetate and allyl benzoate; allyl ethers such as allyl ethyl ether and allyl phenyl ether; 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, perfluoromethyl(meth)acrylate, perfluoropropyl(meth)acrylate, perfluoropropylmethyl(meth)acrylate, vinylpyrrolidone, trimethylolpropane tri(meth)acrylate, and allyl(meth)acrylate. These may be used alone or in combination of two or more.

[0039] <Copolymer (P)> The copolymer (P) is obtained by radical polymerization of an ethylenically unsaturated monomer (A) having a functional group (a) and at least one unsaturated monomer (B) different from the ethylenically unsaturated monomer (A).

[0040] The copolymer (P) in the present invention preferably has a weight average molecular weight Mw of 10,000 or more and 300,000 or less, and more preferably 20,000 or more and 80,000 or less. When the weight average molecular weight Mw of the copolymer (P) is within the above range, it can be suitably used as a coating resin composition. The weight average molecular weight Mw of the copolymer (P) is measured by the same method as described later in the Examples.

[0041] A radical polymerization catalyst is used to synthesize the copolymer (P). Specific examples of the radical polymerization catalyst include, but are not limited to, 2,2-azobisisobutyronitrile, 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylbutyronitrile), t-butylperoxy-2-ethylhexanoate, and dibenzoyl peroxide.

[0042] The amount of the radical polymerization catalyst to be added is not particularly limited, but is preferably 0.3 parts by mass or more and 6.0 parts by mass or less per 100 parts by mass of the total amount of vinyl monomers.

[0043] Although the resin composition of the present invention can be used as a clear coating by itself, in order to impart various functions as a coating, additives generally used in coatings, such as various resins, driers, anti-sagging agents, etc. Furthermore, when blending various pigments generally used in coatings, such as extender pigments, coloring pigments, and anti-rust pigments, it is desirable to blend various additives generally used in coatings, such as pigment dispersants and anti-settling agents.

[0044] The resin composition of the present invention or a paint using the same can be applied to various substrates such as various metals such as iron, tinplate, and aluminum, metal oxides, mortar, concrete, slate boards, etc. Furthermore, it can also be applied to steel materials having water or oil on the surface, and an excellent coating film can be formed by natural drying or forced drying with heat.

[0045] By using the resin composition of the present invention, it is possible to provide a coating film that has good adhesion to various substrates and is excellent in water resistance. [Example]

[0046] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0047] <Synthesis of Coating Resin Composition> [Example 1] (Coating Resin Composition A) 66,000 parts by mass of xylene was added to a reactor equipped with a stirrer, thermometer, reflux condenser, and dropping tank, and the temperature in the reactor was heated to 100 ° C. with stirring. Into this reactor, a mixture consisting of 69.110 parts by mass of methyl methacrylate, 29.620 parts by mass of butyl acrylate, 1.270 parts by mass of Blenmer GA-MA (manufactured by NOF Corporation, Benzoic acid, 3,4,5-trihydroxy-, 2-hydroxy-3-[(2-methyl-1-oxo-2-propen-1-yl)oxy]propyl ester), 19,000 parts by mass of n-butanol, and 0.360 parts by mass of AMBM (2,2'-azobis(2-methylbutyronitrile)) was added dropwise over 180 minutes while the temperature in the reactor was maintained at 100 ° C. Thereafter, stirring was continued for 15 minutes while the temperature in the reactor was maintained at 100 ° C. Next, a mixed solution consisting of 11,000 parts by mass of xylene and 1,300 parts by mass of 2,2'-azobis(2-methylbutyronitrile) was divided into six portions and added every 15 minutes while the temperature in the reactor was maintained at 100°C. Thereafter, the temperature in the reactor was maintained at 100°C and stirring was continued for 2 hours. After cooling, 4,000 parts by mass of xylene was added and the mixture was stirred until homogenous, thereby obtaining a coating resin composition A of Example 1.

[0048] [Examples 2 to 4 and Comparative Examples 1 to 3] (Coating Resin Compositions B to G) Coating resin compositions BG of Examples 2 to 4 and Comparative Examples 1 to 3 were prepared in the same manner as coating resin composition A, except that the formulation shown in Table 1 was followed. Details of *1 in Table 1 are as follows: *1: VISIOMER HEMA-P70M (70% by weight of reaction product of 2-hydroxyethyl methacrylate and phosphoric anhydride, 30% by weight of methyl methacrylate)

[0049] <Preparation of Coating Compositions A to G> Coating resin compositions A, C, D, E, and G were not prepared, and were used as coating compositions A, C, D, E, and G, respectively. Coating composition B was prepared by mixing 100 parts by mass of coating resin composition B with 18 parts by mass of an isocyanate curing agent (Desmodur N75MPA / X-JP, manufactured by Sumika Covestro Co., Ltd.) and 0.02 parts by mass of a curing catalyst (0.1% butyl acetate solution of 1,3-diacetoxy-1,1,3,3-tetrabutyldistannoxane). Coating resin composition F was also prepared in the same manner as above.

[0050] <Preparation of test plate> Using a 6 mil applicator, the prepared coating compositions A to G were each applied to the following substrates measuring 70 mm x 150 mm, and then dried at 100°C for 20 minutes to obtain test panels. As substrates, a degreased steel plate, a degreased aluminum plate, a degreased black steel plate, a slate plate from which dirt from cutting had been removed, a steel plate with a water-wettable surface, and a steel plate with an oily surface were prepared. The steel plate with a water-wettable surface was prepared by wetting the painted surface of a degreased steel plate with a water-soaked cloth. The steel plate with an oily surface was prepared by degreasing the steel plate and then applying 1.0 g / m of rust-preventive oil [JIS K 2246 (1994) NP-3-2]. 2 The coating was applied evenly so that the thickness was as shown in the figure, and the coating was left to stand for one week in an atmosphere of 23°C and 50% RH. For evaluating water resistance, each of the prepared coating compositions A to G was applied to a degreased steel plate of 70 mm x 150 mm, and dried at 100°C for 20 minutes to prepare a test plate.

[0051] [Characteristics] The coating resin composition obtained above was measured for the following properties. The measurement results are shown in Table 1.

[0052] (heated residue) 1.0 g of the above coating resin composition was precisely weighed into an aluminum cup and dried for 30 minutes in an oven at 150° C. After drying, the mass of the residue was precisely weighed, and the ratio of the mass of the residue to the original mass was calculated as the heating residue (mass %).

[0053] (acid number) The acid value of the coating resin composition was determined in accordance with JIS K 5601-2-1:1999.

[0054] (Number average molecular weight Mn) The number-average molecular weight Mn of the coating resin composition was measured by SEC (size exclusion chromatography, product name "HLC-8420GPC", manufactured by Tosoh Corporation) equipped with a differential refractive index (RI) detector using a TSKgel column SuperMultiporeHZ-M (manufactured by Tosoh Corporation). SEC conditions included using tetrahydrofuran as the developing solvent, a flow rate of 0.35 ml / min, and a temperature of 40°C. TSK standard polystyrene (manufactured by Tosoh Corporation) was used as the standard substance.

[0055] (Weight average molecular weight Mw) The weight-average molecular weight Mw of the coating resin composition was measured by SEC (size exclusion chromatography, product name "HLC-8420GPC", manufactured by Tosoh Corporation) equipped with a differential refractive index (RI) detector using a TSKgel column SuperMultiporeHZ-M (manufactured by Tosoh Corporation). SEC conditions included using tetrahydrofuran as the developing solvent, a flow rate of 0.35 ml / min, and a temperature of 40°C. TSK standard polystyrene (manufactured by Tosoh Corporation) was used as the standard substance.

[0056] (Mw / Mn) Mw / Mn was calculated from the number average molecular weight and the weight average molecular weight.

[0057] [evaluation] The test plates obtained in the examples and comparative examples were evaluated as follows. The evaluation results are shown in Table 1.

[0058] (Adhesion (cross-cut method)) In accordance with the adhesion test method specified in JIS K 5600, 100 1 mm wide grids were made on each of the obtained test plates using a cutter knife, and a peel test was performed using cellophane tape (manufactured by Nichiban Co., Ltd.) and visually evaluated according to the following criteria. A: There is no peeling in the grid and no abnormalities on the coating surface. B: The number of holes remaining on the coating film is 95 or more, and there is no practical problem with adhesion. C: The number of holes remaining on the coating film is 94 or less.

[0059] (water resistance) The obtained test plate (substrate: steel plate) was immersed in deionized water at 23°C for 360 hours, and then the appearance and adhesion of the coating film were evaluated immediately after wiping off the water droplets on the surface. A: There is no blistering of the coating film, and no peeling of the coating film is observed in the adhesion evaluation. B: Some peeling is observed on the edges of the grid, but the coating film is not blistered and there is no practical problem with water resistance. C: The coating film is blistered or peeled off from the substrate.

[0060] [Table 1]

[0061] As shown in Table 1, the coating resin compositions of Examples 1 to 4, which contain copolymer (P) using ethylenically unsaturated monomer (A) having functional group (a) as a monomer, are superior in adhesion to various substrates and in water resistance of the coating film compared to Comparative Example 1, which does not have functional group (a), and Comparative Examples 2 and 3, which use other functional groups. [Industrial Applicability]

[0062] The resin composition of the present invention has high adhesion to various substrates such as metals, metal oxides, mortar, and concrete, comparable to that of epoxy resins, and also has excellent water resistance, making it suitable as a resin composition for coating various substrates.

Claims

1. A resin composition containing a copolymer (P) obtained by radical polymerization of at least one ethylenically unsaturated monomer (A) having a functional group (a) represented by the following formula (I) and at least one unsaturated monomer (B) different from the ethylenically unsaturated monomer (A), A resin composition in which the content of the functional group (a) in the copolymer (P) is 0.02 mmol / g or more and 0.5 mmol / g or less. 【Chemical 1】 (In formula (I), X is a hydrogen atom or a hydroxyl group.)

2. 2. The resin composition according to claim 1, wherein the functional group (a) is a functional group represented by the following formula (II): 【Chemistry 2】

3. 3. The resin composition according to claim 1, wherein the copolymer (P) has a weight average molecular weight Mw of 10,000 or more and 300,000 or less.

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