JP2009067891A - Aqueous resin composition and coating agent containing the same - Google Patents

Abstract

An object of the present invention is to provide an aqueous resin composition capable of forming a coating film having very excellent solvent resistance and a coating agent containing the same.
[MEANS FOR SOLVING PROBLEMS] Core-shell type resin particles (A) in which a shell layer is made of a urethane resin (a1) having a carboxyl group and a core layer is made of a vinyl polymer (a2) having a basic nitrogen atom-containing group. ), A compound (B) having a hydrolyzable silyl group or silanol group and an epoxy group, and an aqueous medium, and the core-shell type resin particles (A) are dispersed in the aqueous medium. The present invention relates to an aqueous resin composition and a coating agent.
[Selection figure] None

Description

  The present invention relates to an aqueous resin composition in which core-shell type resin particles are dispersed in an aqueous medium, and a coating agent capable of forming a coating film for the purpose of surface protection and imparting design properties to various substrates.

  The coating agent has the role of protecting the surface of the substrate from external factors in addition to the role of imparting design properties to the surface of various substrates. In recent years, there has been a demand for high durability of the coating film to be formed. It is growing. The coating agent capable of forming a highly durable coating film includes, for example, polymer particles, a polyfunctional epoxy compound, and an aqueous medium, and the polymer particles are composed of at least two layers, of which A phase Is an curable polymer aqueous dispersion in which is composed of a carboxyl group-containing polymer and the B phase is an ethylenic polymer having a basic nitrogen atom-containing group (see, for example, Patent Document 1).

If it is a coating agent which consists of the said curable polymer aqueous dispersion liquid, the coating film which has some favorable water resistance and solvent resistance is possible.
However, in order to further ensure the protection of the substrate, a coating agent capable of forming a coating film having a very high level of solvent resistance is required. Then, the required performance was not one step away.

  On the other hand, as the coating agent, a coating agent composed of composite particles of a urethane resin and a vinyl resin, for example, a vinyl polymer chain portion and a urethane polymer chain portion are bonded to a silicon atom and an oxygen atom. It is known that a vinyl-urethane copolymer bonded through a connecting portion having an adhesive can be used for an aqueous coating agent or the like (for example, see Patent Document 2).

  However, the aqueous coating agent composed of the vinyl-urethane copolymer is difficult to form a film because it is difficult to form a film, and as a result, it can exhibit a very high level of solvent resistance. It was sometimes difficult.

JP 9-235332 A International Publication No. 2005/054341 Pamphlet

  The problem to be solved by the present invention is to provide an aqueous resin composition capable of forming a coating film having very excellent solvent resistance and a coating agent containing the same.

  As a result of investigations to solve the above problems, the inventors of the present invention are core-shell type resin particles composed of a combination of different types of resins, urethane resin and vinyl polymer, each having a carboxyl group and a basic nitrogen atom. A composition comprising a specific group of functional groups, a containing group, and a compound having a hydrolyzable silyl group or silanol group and an epoxy group as its curing agent is significantly superior to conventional products. It was found that a coating film having high solvent resistance can be formed.

  That is, the present invention provides a core-shell type resin particle (A) in which the shell layer is made of a urethane resin (a1) having a carboxyl group, and the core layer is made of a vinyl polymer (a2) having a basic nitrogen atom-containing group. A compound (B) having a hydrolyzable silyl group or silanol group and an epoxy group, and an aqueous medium, wherein the core-shell type resin particles (A) are dispersed in the aqueous medium. The present invention relates to a characteristic aqueous resin composition and a coating agent.

  Since the aqueous resin composition of the present invention has extremely excellent solvent resistance at room temperature, it can be used, for example, as a coating agent for protecting various substrate surfaces and imparting design properties.

  The present invention relates to a core-shell type resin particle (A) in which the shell layer is made of a urethane resin (a1) having a carboxyl group and the core layer is made of a vinyl polymer (a2) having a basic nitrogen atom-containing group, hydrolysis Containing a compound (B) having a reactive silyl group or silanol group and an epoxy group, an aqueous medium, and various additives as required, wherein the core-shell type resin particles (A) are an aqueous medium. This is an aqueous resin composition dispersed therein.

First, the core-shell type resin particles (A) will be described.
The core-shell type resin particle (A) is a resin particle having a two-layer structure of a shell layer and a core layer, and the core layer and the shell layer are not substantially bonded or have a film-forming property. It is preferable to form a bond that does not inhibit the above. In other words, the crosslinking density inside the resin particles (A) dispersed in the aqueous medium is preferably as low as possible from the viewpoint of imparting excellent film forming properties to the aqueous resin composition of the present invention.

  The degree of cross-linking inside the core-shell type resin particles (A) is such that the aqueous dispersion of the resin particles (A) and an organic solvent are mixed and the resin particles (A) are easily dissolved in the solvent. It can be evaluated by examining. Specifically, a method of measuring the light transmittance (transparency) of a mixed liquid of an aqueous dispersion of core / shell type resin particles (A) and tetrahydrofuran is mentioned. Although a more specific method will be described in the examples described later, the light transmittance (wavelength 640 nm) of the mixed solution in which the concentration of the resin particles (A) is 4% by mass is preferably 70% or more.

  The core-shell type referred to in the present invention refers to a configuration in which the vinyl polymer (a2) constituting the core layer is present in the urethane resin (a1) constituting the shell layer. At that time, the vinyl polymer (a2) may be dispersed in a plurality of particles in the urethane resin (a1), and the vinyl polymer (a2) is concentrically formed with the urethane resin (a1) in the core layer. May be formed.

  Moreover, it is preferable that the said core-shell type resin particle (A) is a particle diameter of the range of 5-100 nm from a viewpoint of forming into a dense film and improving the solvent resistance of a coating film.

  The core-shell type resin particles (A) have a mass ratio [(a1) / (a2)] of the urethane resin (a1) and the acrylic polymer (a2) of 10/90 to 70/30. If it exists, since the aqueous resin composition which can form the coating film which is excellent in film forming property and excellent in solvent resistance can be obtained, it is preferable.

  The core-shell type resin particles (A) have a carboxyl group as a hydrophilic group necessary for dispersion in an aqueous medium. The carboxyl group is preferably present in the urethane resin (a1) constituting the shell layer that is the outermost part of the resin particles (A). The carboxyl group may be neutralized with a basic compound described later. Moreover, the said carboxyl group also contributes to reaction with the compound (B) which has a hydrolyzable silyl group or silanol group mentioned later, and an epoxy group.

  The urethane resin (a1) that forms the shell layer of the core-shell type resin particles (A) is a urethane resin obtained by reacting a polyol and a polyisocyanate, and has a carboxyl group that contributes to hydrophilicity.

  The urethane resin (a1) preferably has a carboxyl group-derived acid value in the range of 10 to 50, and more preferably in the range of 15 to 35. If the urethane resin (a1) has an acid value in such a range, the dispersion stability of the core-shell particles can be increased, and the reactivity with the compound (B) described later can be increased, and the resulting coating film can be obtained. Solvent resistance can be improved.

  Moreover, the amount of the carboxyl group contained in the core / shell type resin particles (A) is such that the acid value derived from the carboxyl group with respect to the whole core / shell type resin particles (A) is in the range of 2 to 30, It is preferable because the dispersion stability of the core / shell particles can be increased, the reactivity with the compound (B) described later can be increased, and the solvent resistance of the resulting coating film can be improved.

  In addition to the carboxyl group, the urethane resin (a1) may have an amino group, an imino group, a hydroxyl group, a hydrolyzable silyl group, which is a functional group capable of reacting with the compound (B) as another functional group as necessary. It may have a silanol group or the like.

  In particular, the urethane resin having a hydrolyzable silyl group or silanol group as the other functional group reacts with the hydrolyzable silyl group or silanol group possessed by the compound (B). It is preferable because the solvent property is further improved.

  When the urethane resin (a1) has a weight average molecular weight in the range of 5,000 to 100,000, an aqueous resin composition capable of forming a coating film having excellent film forming properties and excellent solvent resistance is obtained. Is preferable.

  The vinyl polymer (a2) constituting the core layer of the core-shell type resin particles (A) has a basic nitrogen atom-containing group. The vinyl polymer (a2) containing a basic nitrogen atom-containing group contributes to the reaction with the epoxy group of the compound (B). The basic nitrogen atom-containing group also functions as a catalyst for promoting the reaction between the carboxyl group of the urethane resin (a1) and the epoxy group of the compound (B).

  As the basic nitrogen atom-containing group, for example, a primary amino group, a secondary amino group, or a tertiary amino group can be used. Among them, the tertiary amino group is highly reactive with the epoxy group possessed by the compound (B), and promotes the reaction between the carboxyl group possessed by the urethane resin (a1) and the epoxy group possessed by the compound (B). High effect. Therefore, it is preferable to use a tertiary amino group as the basic nitrogen atom-containing group in order to obtain an aqueous resin composition capable of forming a coating film excellent in solvent resistance.

  The content of the basic nitrogen atom-containing group maintains the reactivity with the compound (B), the excellent solvent resistance and water resistance of the resulting coating film, and the good dispersion stability of the resin particles (A). From the viewpoint of, it is preferably 10 to 700 mmol / Kg with respect to the total amount of the vinyl polymer (a2).

  In addition, the content of the basic nitrogen atom-containing group with respect to the entire core / shell type resin particle (A) provides reactivity with the compound (B), dispersion stability, and excellent solvent resistance in the resulting crosslinked coating film. From this viewpoint, the amount is preferably in the range of 3 to 600 mmol / Kg with respect to the total amount of the core-shell type resin particles (A).

  The weight average molecular weight of the vinyl polymer (a2) is preferably in the range of 100,000 to 2,000,000 from the viewpoint of solvent resistance of the coating film.

The core-shell type resin particles (A) are produced by, for example, producing an aqueous dispersion of a urethane resin (a1) by reacting a polyol and a polyisocyanate, and then polymerizing a vinyl monomer in the aqueous dispersion. Can be manufactured.
Moreover, when using what does not have a hydrophilic group for the said vinyl polymer (a2), the said resin particle (A) separates the said urethane resin (a1) and the said vinyl polymer (a2) separately. Or by mixing them with an aqueous medium.
Moreover, you may perform manufacture of the said resin particle (A) in presence of the compound (B) mentioned later as needed.

  The aqueous dispersion of the urethane resin (a1) is prepared by, for example, reacting a polyol containing a carboxyl group-containing polyol with a polyisocyanate in the absence of a solvent or in the presence of an organic solvent to produce a carboxyl group-containing urethane prepolymer. Subsequently, the neutralized carboxyl group can be mixed with an aqueous medium to make it aqueous, and if necessary, it can be reacted with a chain extender such as polyamine to adjust to a desired molecular weight.

  The reaction between the polyol and the polyisocyanate is preferably carried out, for example, in an equivalent ratio of the isocyanate group of the polyisocyanate to the hydroxyl group of the polyol in the range of 1.05 to 3, It is more preferable to carry out within a range.

  Further, when the urethane resin (a1) is dispersed in the aqueous medium, a machine such as a homogenizer may be used as necessary.

In addition, the polymerization of the vinyl polymer (a2) is performed by supplying the vinyl monomer and the polymerization initiator separately or a mixture thereof in a batch or divided into the aqueous dispersion of the urethane resin (a1). And a method of polymerizing the vinyl monomer in the urethane resin (a1) particles dispersed in an aqueous medium.
At this time, the vinyl monomer is not supplied into the aqueous dispersion of the urethane resin (a1) together with the surfactant, but needs to be supplied alone. As a result, the vinyl monomer cannot be stably present in the aqueous medium, and is polymerized inside the already existing urethane resin (a1) particles. As a result, core-shell type polymer particles (A) having the urethane resin (a1) in the shell layer and the vinyl polymer (a2) in the core layer can be produced.

  Moreover, when manufacturing the said resin particle (A), when the viscosity of urethane resin (a1) is high and it is not excellent in workability | operativity, the said vinyl monomer can also be added previously as a reactive diluent. That is, the resin particles (A) are produced by a method in which a urethane resin (a1) and the vinyl monomer are mixed in advance in an aqueous medium and then the vinyl monomer is polymerized. You can also.

  Here, examples of polyols that can be used in the production of the urethane resin (a1) include polyester polyols, polyether polyols, polycarbonate polyols, polyacetal polyols, polyacrylate polyols, polyester amide polyols, polythioether polyols, polyolefin polyols such as polybutadiene, and the like. Can be used alone or in combination of two or more.

  Examples of the polyester polyol include those obtained by an esterification reaction of a low molecular weight polyol and a polycarboxylic acid, polyesters obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymers of these. Polymerized polyester or the like can be used.

  Examples of the low molecular weight polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Neopentyl glycol, 1,8-octanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight 300-6000), dipropylene glycol, tripropylene glycol Bis-hydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, hydroquinone and their alkylene oxide adducts can do.

  Examples of the polycarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid. Acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-p , P′-dicarboxylic acid, and anhydrides or ester-forming derivatives thereof can be used.

  As the polyester polyol, in addition to the polyol and polycarboxylic acid, p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, ester-forming derivatives of these hydroxybenzoic acids, and the like are reacted. The one obtained can be used.

  In addition, as the polyether polyol, for example, one obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator can be used.

  Examples of the initiator include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, Trimethylolethane, trimethylolpropane, sorbitol, sucrose, aconite sugar, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, dihydroxybenzoic acid, hydroxyphthalic acid, 1,2,3- Propane trithiol or the like can be used.

  As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, cyclohexylene and the like can be used.

  Examples of the polycarbonate polyol include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, cyclohexanedimethanol and other glycols and caprolactone, diphenyl carbonate, dimethyl carbonate, phosgene and the like. What was obtained by reacting can be used.

  As the above-described polyol, it is preferable to use the polyester polyol or the polycarbonate polyol from the viewpoint of further improving the solvent resistance of the crosslinked coating film formed by the aqueous resin composition of the present invention. Moreover, as said polyol, it is preferable to use a thing with a weight average molecular weight of 300-10000, Preferably it is 500-5000.

  Moreover, when manufacturing a urethane resin (a1), it is preferable to use a carboxyl group-containing polyol together for the purpose of introducing a carboxyl group into the urethane resin (a1).

  Examples of the carboxyl group-containing polyol include 2,2′-dimethylolpropionic acid, 2,2′-dimethylolbutanoic acid, 2,2′-dimethylolbutyric acid, 2,2′-dimethylolvaleric acid, and the like. Can do. Moreover, the carboxyl group-containing polyester polyol obtained by making the said carboxyl group-containing polyol and various polycarboxylic acids react can also be used.

  Moreover, as polyisocyanate used when manufacturing the said urethane resin (a1), aromatic diisocyanates, such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, Aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate can be used alone or in combination of two or more.

  As the polyisocyanate, an aliphatic diisocyanate or an alicyclic diisocyanate is preferably used from the viewpoint of further improving the solvent resistance of the crosslinked coating film formed by the aqueous resin composition of the present invention. Preference is given to using methylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate.

  Examples of basic compounds that can be used when neutralizing the carboxyl group in the urethane resin (a1) include organic amines such as ammonia, triethylamine, and morpholine, alkanolamines such as monoethanolamine and diethylethanolamine, A metal containing Na, K, Li or the like can be used. The amount of the basic compound used is [basic compound / carboxyl group] = 0.5 to 3.0 (moles) with respect to the carboxyl group from the viewpoint of improving the water dispersion stability of the resulting aqueous resin composition. The ratio is preferably in the range of 0.9 to 2.0 (molar ratio).

  When producing the urethane resin (a1), for the purpose of designing a polyurethane resin having physical properties such as various mechanical properties and thermal properties, polyamine, other active hydrogen atom-containing compounds, etc. Chain extenders may be used.

  Examples of such polyamines include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, and 3,3′-. Diamines such as dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, Diamines containing one primary amino group and one secondary amino group such as N-methylaminopropylamine; polyamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, Hydrazines such as N, N'-dimethylhydrazine and 1,6-hexamethylenebishydrazine; Dihydrazides such as succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide; , Semicarbazides such as 3-semicarbazide-propyl-carbazate, semicarbazide-3-semicarbazide methyl-3,5,5-trimethylcyclohexane, and the like can be used.

  When polyamine is used as the chain extender, it is preferably used in the range where the equivalent ratio of the amino group and excess isocyanate group of the polyamine is 1.9 or less (equivalent ratio). More preferably, it is used in the range of 0.0 (equivalent ratio). By using the chain extender in the above-described range, the solvent resistance and mechanical strength of the coating film formed by the obtained aqueous resin composition can be improved.

  Examples of the other active hydrogen-containing compound include ethylene glycol, diethylene recall, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, and sucrose. , Glycols such as methylene glycol, glycerin, sorbitol; phenols such as bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, hydroquinone , And water can be used singly or in combination of two or more in a range where the storage stability of the aqueous paint of the present invention does not deteriorate.

  When the urethane resin (a1) is produced in the presence of an organic solvent, for example, ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetate esters such as ethyl acetate and butyl acetate; Nitriles such as acetonitrile; amides such as dimethylformamide and N-methylpyrrolidone can be used alone or in combination of two or more. In particular, it is preferable to use methyl ethyl ketone or N-methylpyrrolidone because the urethane resin (a1) is easily dissolved.

  Moreover, as a vinyl monomer used when manufacturing the vinyl polymer (a2) which comprises the core layer of the core-shell type resin particle (A) used by this invention, in a vinyl polymer (a2), For the purpose of imparting a basic nitrogen atom-containing group, a vinyl monomer containing a basic nitrogen atom-containing group is used.

  The vinyl monomer containing a basic nitrogen atom-containing group is not particularly limited as long as it can react with the epoxy group of the compound (B). For example, N, N-dimethylaminoethyl (meth) acrylate N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N- [ 2- (meth) acryloyloxyethyl] piperidine, N- [2- (meth) acryloyloxyethyl] pyrrolidine, N- [2- (meth) acryloyloxyethyl] morpholine, 4- [N, N-dimethylamino] styrene 4- [N, N-diethylamino] styrene, 2-vinylpyridine, 4-vinylpyri Tertiary amino group-containing polymerizable monomer such as N; secondary amino group-containing polymerizable monomer such as N-methylaminoethyl (meth) acrylate and Nt-butylaminoethyl (meth) acrylate; Examples include primary amino group-containing polymerizable monomers such as acrylate, aminoethyl acrylate, aminopropyl (meth) acrylate, amino-n-butyl (meth) acrylate, butylvinylbenzylamine, vinylphenylamine, and p-aminostyrene. One or a mixture of two or more of these can be used.

  Among these, in particular, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) Acrylate, acrylate of N, N-diethylaminopropyl (meth) acrylate, N- [2- (meth) acryloyloxyethyl] piperidine, N- [2- (meth) acryloyloxyethyl] pyrrolidine, N- [2- (meta ) Tertiary amino group-containing polymerizable monomer such as acryloyloxyethyl] morpholine, 4- [N, N-dimethylamino] styrene, 4- [N, N-diethylamino] styrene, 2-vinylpyridine, 4-vinylpyridine and the like. Can be used for copolymerization with other vinyl monomers described later Excellent preferable because of a large effect of improving the solvent resistance.

  Moreover, as a method of providing a basic nitrogen atom-containing group in the vinyl polymer (a2), for example, after producing a polymer using N-vinylformamide as a vinyl monomer, There is also a method of forming a primary amino group by hydrolyzing an amide group.

  Further, in the production of the vinyl polymer (a2), in addition to the vinyl monomer containing the basic nitrogen atom-containing group, when other vinyl monomers are used in combination, the base in the vinyl polymer (a2) The amount of the reactive nitrogen atom-containing group can be adjusted to a preferred range.

  The other vinyl monomer is not particularly limited as long as it is copolymerizable with a vinyl monomer containing a basic nitrogen atom-containing group. For example, methyl (meth) acrylate, ethyl (meth) acrylate , N-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate , Nonyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, etc. Acrylic ester 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, 2,2,3,3, -tetrafluoro Fluorine-containing vinyl monomers such as propyl (meth) acrylate and β- (perfluorooctyl) ethyl (meth) acrylate; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatate; methyl vinyl ether, Vinyl ethers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, amyl vinyl ether, hexyl vinyl ether; nitriles of unsaturated carboxylic acids such as (meth) acrylonitrile; styrene, α-methylstyrene, vinyl toluene, vinyl acetate Sole, α-halostyrene, vinyl naphthalene, vinyl compound having an aromatic ring such as divinylstyrene; isoprene, chloroprene, butadiene, ethylene, tetrafluoroethylene, vinylidene fluoride, N-vinylpyrrolidone, etc., and one of these Alternatively, a mixture of two or more types can be used. Of these, (meth) acrylic acid esters are preferred because they are particularly easy to polymerize and are excellent in physical properties represented by solvent resistance of the resulting coating film.

  Further, as other vinyl monomers, vinyl monomers containing reactive functional groups other than basic nitrogen atom-containing groups can be used in combination, for example, glycidyl (meth) acrylate, allyl glycidyl ether. , Epoxy group-containing polymerizable monomers such as 4-vinylcyclohexane monoepoxide; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, glycerol mono (meth) acrylate Hydroxyl group-containing polymerizable monomers such as: (meth) acrylamide, N-monoalkyl (meth) acrylamide, amide group-containing polymerizable monomers such as N, N-dialkyl (meth) acrylamide; N-methylol (meth) Acrylamide, N-isopropoxymethyl (meth) a Methylolamide groups such as rilamide, N-butoxymethyl (meth) acrylamide, N-isobutoxymethyl (meth) acrylamide, and alkoxylated-containing polymerizable monomers; aziridinyl groups such as 2-aziridinylethyl (meth) acrylate -Containing polymerizable monomer; isocyanate group such as (meth) acryloyl isocyanate, phenol adduct of (meth) acryloyl isocyanate ethyl, and / or blocked isocyanate group-containing polymerizable monomer; 2-isopropenyl- Oxazoline group-containing polymerizable monomers such as 2-oxazoline, 2-vinyl-2-oxazoline and 2-oxazodinylethyl (meth) acrylate; Cyclopentenyl group-containing polymerizable monomers such as dicyclopentenyl (meth) acrylate Acrolein, diacetone (meta Carbonyl group-containing polymerizable monomers such as acrylamide; acetoacetyl group-containing polymerizable monomers such as acetoacetoxyethyl (meth) acrylate; (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, β -(Meth) acryloyloxyethyl hydrogen succinate, β- (meth) acryloyloxyethyl hydrogen phthalate, or carboxyl group-containing monomers such as half esters or salts thereof, and the like. Alternatively, a mixture of two or more types can be used.

  As the other vinyl monomer, it is particularly preferable to use a vinyl monomer having a hydrolyzable silyl group or silanol group in combination. Since the hydrolyzable silyl group of the vinyl polymer (a2) obtained by using such a vinyl monomer in combination reacts with the hydrolyzable silyl group or silanol group of the compound (B), the resulting coating film The solvent resistance can be further improved.

  Examples of the vinyl monomer having a hydrolyzable silyl group or silanol group include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinyltriacetoxysilane, vinyltriisoiso Propoxysilane, allyltrimethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, γ- (meth) acryl Roxypropyltriethoxysilane, γ- (meth) acryloxypropyltriisopropoxysilane, and the like can be used.

  On the other hand, as a method for imparting a hydrolyzable silyl group or silanol group to the vinyl polymer (a2), a hydrolyzable silyl group or silanol group and a mercapto group are used as a chain transfer agent during the production of the vinyl polymer (a2). The functional group can also be imparted to the molecular terminal of the vinyl polymer (a2) using a compound having As the compound having a hydrolyzable silyl group or silanol group and a mercapto group, for example, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane and the like can be used.

  For the purpose of imparting other reactive functional groups to the vinyl polymer (a2), vinyl monomers containing reactive functional groups other than basic nitrogen atom-containing groups are used as the other vinyl monomers. In order to prevent the film-forming property of the core-shell type resin particles (A) from being hindered, the resin particles (A) are in the stage before forming the film in which the resin particles (A) are dispersed in the aqueous medium. Select a combination of reactive functional groups that do not substantially cross-link internally and cross-link between the resin particles (A) after the film is formed, and further, the amount of reactive functional groups used inhibits film-forming properties. It is preferable to adjust to a range that does not exist.

  The other vinyl monomer is such that the content of the basic nitrogen atom-containing group in the vinyl polymer (a2) is in the range of 10 to 700 mmol / Kg with respect to the total amount of the vinyl polymer (a2). It is preferable to use for.

  Examples of the polymerization initiator that can be used in producing the vinyl polymer (a2) include radical polymerization initiators such as persulfates, organic peroxides, and hydrogen peroxide, and 4,4′-azobis ( An azo initiator such as 4-cyanovaleric acid) or 2,2′-azobis (2-amidinopropane) dihydrochloride can be used. The radical polymerization initiator may be used as a redox polymerization initiator in combination with a reducing agent described later.

  Examples of the persulfates that are representative of the polymerization initiator include potassium persulfate, sodium persulfate, and ammonium persulfate. Specific examples of organic peroxides include, for example, peroxidation. Diacyl peroxides such as benzoyl, lauroyl peroxide and decanoyl peroxide, dialkyl peroxides such as t-butylcumyl peroxide and dicumyl peroxide, t-butylperoxylaurate, t-butylperoxybenzoate, etc. Peroxyesters, cumene hydroperoxide, paramentane hydroperoxide, hydroperoxides such as t-butyl hydroperoxide, and the like can be used.

  Examples of the reducing agent include ascorbic acid and its salt, erythorbic acid and its salt, tartaric acid and its salt, citric acid and its salt, metal salt of formaldehyde sulfoxylate, sodium thiosulfate, sodium bisulfite, chloride Ferric iron or the like can be used.

  The polymerization initiator may be used in an amount that allows the polymerization to proceed smoothly, but is preferably less in terms of maintaining the water resistance of the resulting coating film, and is used for the production of the vinyl polymer (a2). The total amount of vinyl monomer is preferably 1.0% by weight or less (in the case of a redox polymerization initiator used in combination with a reducing agent, the total amount of an oxidizing agent and a reducing agent).

  Next, the compound (B) having a hydrolyzable silyl group or silanol group and an epoxy group used in the present invention will be described.

  The compound (B) reacts with the carboxyl group or basic nitrogen atom-containing group of the core-shell type resin particle (A) to form a crosslinked coating film excellent in solvent resistance. It is an ingredient.

  The compound (B) has a hydrolyzable silyl group or silanol group, or both. The hydrolyzable silyl group and silanol group react between the functional groups to form a polyfunctional epoxy compound.

  The hydrolyzable silyl group and silanol group also act as a silane coupling agent that connects the core-shell type resin particles (A) and the base material to which the aqueous coating agent is applied. There is also an effect of remarkably improving the adhesion to glass.

  Examples of the hydrolyzable silyl group include an atomic group containing a silicon atom to which an alkoxy group, a substituted alkoxy group, a phenoxy group, a halogen atom, an isopropenyloxy group, an acyloxy group, iminooxy, or the like is bonded. It refers to those that produce silanol groups. Of these, an alkoxysilyl group, a phenoxysilyl group, a halosilyl group, an isopropenyloxysilyl group, an acyloxysilyl group, an iminooxysilyl group, or the like can be used.

  Moreover, the epoxy group which the said compound (B) has reacts with the carboxyl group and basic nitrogen atom containing group which the said resin particle (A) has. Thereby, it is possible to form a crosslinked coating film having very excellent solvent resistance.

Examples of the compound (B) include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethylmethyldiethoxysilane or γ-glycid Epoxysilane compounds such as xylpropyltriisopropenyloxysilane can be used.
Further, adducts of isocyanate silane and glycidyl such as γ-isocyanatopropyltriisopropenyloxysilane or γ-isocyanatopropyltrimethoxysilane, and aminosilanes and diepoxy such as γ-aminopropyltrimethoxysilane An adduct with a compound or a compound obtained by partial hydrolytic condensation of epoxysilane can also be used.

  Moreover, as said compound (B), the high molecular weight compound which has a hydrolyzable silyl group or silanol group, and an epoxy group other than what was mentioned above can be used.

  As the high molecular weight compound, for example, a vinyl polymer having a hydrolyzable silyl group or silanol group and an epoxy group, or a silicone resin having an epoxy group such as cyclic tetrasiloxane can be used.

  The vinyl polymer having a hydrolyzable silyl group or silanol group and an epoxy group, for example, radically copolymerizes a hydrolyzable silyl group-containing vinyl monomer and an epoxy group-containing vinyl monomer in the presence of a solution. It can be produced by a method or a method of radical (co) polymerizing a monomer mixture containing an epoxy group-containing vinyl monomer in the presence of a solution in the presence of a hydrolyzable silyl group-containing chain transfer agent.

  As the silicone resin having an epoxy group, for example, cyclic tetrasiloxane can be used, and a compound represented by the following formula [I] can be used.

但し、式［Ｉ］中の、「Ｇｌｙ」は３−グリシドキシプロピル基を表す。

However, “Gly” in the formula [I] represents a 3-glycidoxypropyl group.

  When the compound (B) forms a coating film excellent in solvent resistance and obtains the aqueous resin composition of the present invention excellent in storage stability, the carboxyl contained in the core-shell type resin particles (A) It is preferable to use in the range of 0.3-3.0 mol with respect to 1 mol of group.

  Various additives can be used in combination with the aqueous resin composition of the present invention as required. Especially, it is preferable to use a curing catalyst together from a viewpoint of forming the crosslinked coating film excellent in solvent resistance.

  Examples of the curing catalyst include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, tetraisopropyl titanate, tetra-n-butyl titanate, tin octylate, lead octylate, cobalt octylate, and zinc octylate. Calcium octylate, zinc naphthenate, cobalt naphthenate, di-n-butyltin diacetate, di-n-butyltin dioctoate, di-n-butyltin dilaurate, di-n-butyltin maleate, p-toluenesulfone Acid, trichloroacetic acid, phosphoric acid, monoalkyl phosphoric acid, dialkyl phosphoric acid, monoalkyl phosphorous acid, dialkyl phosphorous acid and the like can be used.

  Moreover, as an aqueous medium used by this invention, only water may be used and the mixed solution of water and a water-soluble solvent may be used. Examples of the water-soluble solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl carbitol, ethyl cellosolve, and butyl cellosolve, and polar solvents such as N-methylpyrrolidone, one or more of these. Can be used.

  The amount of the water-soluble solvent used is preferably reduced as much as possible in consideration of the danger of ignition of the aqueous resin composition of the present invention and safety and hygiene. Therefore, it is particularly preferable to use water alone as the aqueous medium.

  The aqueous resin composition of the present invention is 20 to 20 from the viewpoint of suppressing an abrupt increase in viscosity during production, and improving the productivity of the aqueous resin composition, ease of coating, drying properties, and the like. The non-volatile content is preferably 70% by mass, and more preferably in the range of 30 to 60% by mass.

  Further, the aqueous resin composition of the present invention may contain an emulsifier and a dispersion stabilizer as necessary, but from the viewpoint of suppressing a decrease in water resistance of the crosslinked coating film, it is preferably not contained as much as possible. It is preferable that it is 0.5 mass% or less with respect to solid content of an aqueous resin composition.

  Moreover, the aqueous resin composition of this invention can be used for a coating agent for the purpose of the surface protection of various base materials, and the designability provision to various base materials.

  Examples of the substrate include metal, glass, paper, wood, various plastic films and the like.

  The coating agent of the present invention exhibits extremely excellent solvent resistance against organic solvents such as methanol, ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, and toluene even when the cross-linked coating film has a thickness of about 5 μm. It is possible.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

Various evaluation methods are described below.
[Solvent resistance test]
The aqueous resin compositions obtained in Examples and Comparative Examples were each coated on a glass plate using a 3 mil applicator, (1) a coating film dried at 25 ° C. for 7 days, and (2) 20 ° C. at 140 ° C. A coating film dried for a minute was prepared. The surface of the obtained coating film was rubbed 100 times with a cotton swab soaked in ethanol, and the presence or absence of deterioration of the coating film was observed.
Moreover, the surface of the coating film produced by the same method as described above was rubbed 100 times with a cotton swab soaked with methyl ethyl ketone, and the presence or absence of deterioration of the coating film was observed.

A: There is no change on the surface of the coating film.
○: The surface of the coating film is slightly dissolved and deteriorated.
Δ: Less than 30% of the coating film was peeled off from the glass plate.
X: 30% or more of the coating film was peeled off from the glass plate.

[Measurement of light transmittance of tetrahydrofuran (THF) mixture of resin particles]
As an index of the degree of crosslinking of the resin particles, the light transmittance when the resin particles were mixed with tetrahydrofuran was measured. The aqueous resin composition precisely weighed so that the solid content weight was 1 g and tetrahydrofuran were mixed so that the total amount was 25 g and stirred for 24 hours to prepare a mixed solution. The light transmittance of the obtained mixture was measured with a Shimadzu absorptiometer UV-1200 under the conditions of wavelength: 640 nm, quartz cell length (length of light transmission): 50 mm.

[Measurement of acid value]
The acid value is a numerical value representing the amount of carboxyl groups contained in the urethane resin (a1), and is the number of mg of potassium hydroxide required to neutralize free carboxyl groups contained in 1 g of the urethane resin (a1).

  The aqueous resin composition was coated on a glass plate using a 3 mil applicator and dried at room temperature for 1 hour to prepare a semi-dry coating film. The obtained coating film was peeled off from the glass plate, and 1 g was precisely weighed and dissolved in 100 g of tetrahydrofuran to obtain a measurement sample.

  The measuring method was a neutralization titration method using an aqueous potassium hydroxide solution. Two drops of phenolphthalein are added to the tetrahydrofuran solution in which the measurement sample is dissolved, and a 0.1N aqueous potassium hydroxide solution is added dropwise to change the color of the solution from colorless to light pink. Potassium consumption was measured and the number of mg was determined.

  In addition, about the measurement sample which did not melt | dissolve in tetrahydrofuran, since the measurement by this method is impossible, the preparation amount of the carboxyl group-containing polyol used at the time of manufacture of urethane resin (a1-1) and (a1-2) Was calculated as the acid value of the urethane resin.

[Measurement of weight average molecular weight]
The weight average molecular weight was measured by gel permeation chromatograph (GPC method).

  The aqueous resin composition was coated on a glass plate with a 3 mil applicator and dried at room temperature for 1 hour to prepare a semi-dry coating film. The obtained coating film was peeled off from the glass plate, and 0.4 g was dissolved in 100 g of tetrahydrofuran to obtain a measurement sample.

  As a measuring apparatus, Tosoh Corporation high performance liquid chromatograph HLC-8220 type was used. As a column, Tosoh Corporation column TSK-GEL (HXL-H, G5000HXL, G4000HXL, G3000HXL, G2000HXL) was used in combination.

  Standard polystyrenes (manufactured by Showa Denko KK and Toyo Soda Co., Ltd.) as standard samples (molecular weights: 44.48 million, 4250,000, 288,000, 2750,000, 1.85 million, 860,000, 450,000, 411,000, 35. Calibration curves were created using 50,000, 190,000, 160,000, 96,000, 50,000, 37,000, 198,000, 196,000, 5570, 4000, 2980, 2030, 500). .

  Tetrahydrofuran was used as the eluent and sample solution, and the weight average molecular weight was measured using a RI detector with a flow rate of 1 mL / min, a sample injection amount of 500 μL, and a sample concentration of 0.4%.

[Reference Example 1] Production of Urethane Resin (a1-1) In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, neopentyl glycol, 1,6-hexanediol and adipic acid were added. 100 parts by mass of polyester polyol obtained by reaction, 13 parts by mass of 2,2-dimethylolpropionic acid, 21 parts by mass of 1,4-cyclohexanedimethanol, 43 parts by mass of dicyclohexylmethane diisocyanate, and 36 parts by mass of isophorone diisocyanate, By reacting in a mixed solvent of 59 parts by mass of methyl ethyl ketone and 119 parts by mass of methyl pyrrolidone, an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular end was obtained.

  Next, 10 parts by mass of triethylamine is added to the organic solvent solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and 331 parts by mass of water is added and the urethane resin is sufficiently stirred. An aqueous dispersion was obtained.

  Next, 8 parts by mass of a 25% by mass ethylenediamine aqueous solution is added to the aqueous dispersion, and the resulting polyurethane resin is chain-extended by stirring, followed by aging and desolvation, thereby solid content concentration of 30% by mass. An aqueous dispersion of urethane resin (a1-1) was obtained. The urethane resin (a1-1) obtained here had an acid value of 26.5 and a weight average molecular weight of 73,000.

Reference Example 2 Production of Urethane Resin (a1-2) Polycarbonate diol (“Niporan 980R” manufactured by Nippon Polyurethane Industry Co., Ltd., hydroxyl group in a nitrogen-substituted container equipped with a thermometer, nitrogen gas inlet tube, and stirrer. Equivalent 1000 g / equivalent) 100 parts by mass, 13 parts by mass of 2,2-dimethylolpropionic acid, 21 parts by mass of 1,4-cyclohexanedimethanol, 43 parts by mass of dicyclohexylmethane diisocyanate, 36 parts by mass of isophorone diisocyanate, 59 parts by mass of methyl ethyl ketone The organic solvent solution of the urethane prepolymer which has an isocyanate group in the molecular terminal was obtained by making it react in the mixed solvent of 119 parts by weight of methylpyrrolidone.

  Next, 10 parts by mass of triethylamine is added to the organic solvent solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and 331 parts by mass of water is added and the urethane resin is sufficiently stirred. An aqueous dispersion was obtained.

  Next, 8 parts by mass of a 25% by mass ethylenediamine aqueous solution is added to the aqueous dispersion, and the resulting polyurethane resin is chain-extended by stirring, followed by aging and desolvation, thereby solid content concentration of 30% by mass. An aqueous dispersion of urethane resin (a1-2) was obtained. The urethane resin (a1-2) obtained here had an acid value of 25.9 and a weight average molecular weight of 55,000.

[Reference Example 3] Production of acrylic polymer (a1-3) Detach into a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping monomer mixture, dropping funnel for dropping polymerization catalyst. 200 parts by weight of ionic water, Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd .; polyoxyethylene-1- (allyloxymethyl) alkyl sulfate ammonium salt, solid content 100% by weight) 1.5 parts by weight The temperature was raised to 80 ° C. while blowing nitrogen.

Under stirring, 0.5 parts by mass of ammonium persulfate was added, and then a monomer mixture consisting of 40 parts by mass of n-butyl acrylate, 45 parts by mass of methyl methacrylate and 15 parts by mass of methacrylic acid was added dropwise over 60 minutes for polymerization. I was damned. During this time, the temperature in the reaction vessel was kept at 80 ± 2 ° C. After completion of the dropwise addition of the monomer mixture, the mixture was held at the same temperature for 60 minutes.
Thereafter, the contents were cooled to 30 ° C., and 15 parts of 5% by mass ammonia water was added dropwise at the same temperature over 10 minutes with stirring. Then, it adjusted with deionized water so that solid content concentration might be 30.0 mass%, and filtered with a 100 mesh metal-mesh, and the acrylic polymer for comparison (a1-3) was obtained.

[Example 1] Production of aqueous resin composition (I) Deionized in a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping monomer mixture, dropping funnel for dropping polymerization catalyst 140 parts by mass of water and 100 parts by mass of the aqueous dispersion of the urethane resin (a1-1) obtained in Reference Example 1 were added, and the temperature was raised to 80 ° C. while blowing nitrogen.

In order to obtain a vinyl polymer (a2-1) constituting the core layer with stirring in a reaction vessel heated to 80 ° C., 40 parts by mass of n-butyl acrylate, 58 parts by mass of methyl methacrylate, dimethylaminoethyl methacrylate 2 A monomer mixture consisting of parts by mass and 15 parts by mass of an aqueous ammonium persulfate aqueous solution (concentration: 2% by mass) were dropped from separate dropping funnels over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C. for polymerization. .
After completion of dropping, the mixture was stirred at the same temperature for 60 minutes. Thereafter, the contents are cooled to 30 ° C., 3 parts by weight of γ-glycidoxypropyltrimethoxysilane is added with stirring, and the mixture is adjusted with deionized water so that the solid content concentration becomes 35.0% by mass. The aqueous resin composition (I) of the present invention was obtained by filtering through a 100 mesh wire net.

  The light transmittance of the mixed liquid obtained by mixing the obtained aqueous resin composition (I) and tetrahydrofuran was 97.5%.

[Examples 2 to 4]
Aqueous resin compositions (II) to (IV) were prepared in the same manner as in Example 1 except that the composition and blending ratio were changed to those described in Tables 1 and 2.

[Example 5]
Urethane resin obtained in Reference Example 1, 140 parts by mass of deionized water in a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping monomer mixture, dropping funnel for dropping polymerization catalyst 100 parts by mass of the aqueous dispersion (a1-1) was added, and the temperature was raised to 80 ° C. while blowing nitrogen.

  A single reactor comprising 40 parts by mass of n-butyl acrylate, 58 parts by mass of methyl methacrylate, 2 parts by mass of dimethylaminoethyl methacrylate, and 3 parts by mass of γ-glycidoxypropyltrimethoxysilane with stirring in a reaction vessel heated to 80 ° C. The polymer mixture and 15 parts by mass of an aqueous ammonium persulfate solution (concentration: 2% by mass) were dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C. for polymerization. After completion of dropping, the mixture was stirred at the same temperature for 60 minutes. Thereafter, the contents are cooled to 30 ° C., adjusted with deionized water so that the solid content concentration is 35.0% by mass, and filtered through a 100 mesh wire net to obtain the aqueous resin composition (V) of the present invention. It was. The light transmittance of the mixed liquid obtained by mixing the obtained aqueous resin composition (V) and tetrahydrofuran was 90.7%.

[Comparative Example 1]
In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping the monomer mixture, dropping funnel for dropping the polymerization catalyst, 140 parts by mass of deionized water, for comparison obtained in Reference Example 3 100 parts by mass of an aqueous dispersion of acrylic polymer (a1-3) was added, and the temperature was raised to 80 ° C. while blowing nitrogen.

In a reaction vessel heated to 80 ° C., with stirring, a monomer mixture consisting of 40 parts by mass of n-butyl acrylate, 58 parts by mass of methyl methacrylate, and 2 parts by mass of dimethylaminoethyl methacrylate, an aqueous ammonium persulfate solution (concentration: 2). (Mass%) 15 parts by mass were dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C. for polymerization.
After completion of dropping, the mixture was stirred at the same temperature for 60 minutes. Thereafter, the contents are cooled to 30 ° C., 3 parts by weight of γ-glycidoxypropyltrimethoxysilane is added with stirring, and the mixture is adjusted with deionized water so that the solid content concentration becomes 35.0% by mass. The solution was filtered through a 100 mesh wire mesh to obtain a comparative aqueous resin composition (VI). The light transmittance of the mixed liquid obtained by mixing the obtained aqueous resin composition (VI) and tetrahydrofuran was 92.3%.

[Comparative Example 2]
Urethane resin obtained in Reference Example 1, 140 parts by mass of deionized water in a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping monomer mixture, dropping funnel for dropping polymerization catalyst 100 parts by mass of the aqueous dispersion (a1-1) was added, and the temperature was raised to 80 ° C. while blowing nitrogen.

A monomer mixture consisting of 40 parts by mass of n-butyl acrylate, 58 parts by mass of methyl methacrylate, and 2 parts by mass of dimethylaminoethyl methacrylate, and an aqueous ammonium persulfate solution (concentration: 2 masses) while stirring in a reaction vessel heated to 80 ° C. %) 15 parts by mass were dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C., and polymerized.
After completion of the dropping, the temperature in the reaction vessel was maintained at the same temperature with stirring for 60 minutes. Thereafter, the contents were cooled to 30 ° C., adjusted with deionized water so that the solid content concentration was 35.0% by mass, and filtered through a 100 mesh wire net to obtain a comparative aqueous resin composition. The light transmittance of the mixed liquid obtained by mixing the obtained aqueous resin composition (VII) and tetrahydrofuran was 98.5%.

[Comparative Example 3]
Urethane resin obtained in Reference Example 1, 140 parts by mass of deionized water in a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping monomer mixture, dropping funnel for dropping polymerization catalyst 100 parts by mass of the aqueous dispersion (a1-1) was added, and the temperature was raised to 80 ° C. while blowing nitrogen.

A monomer mixture composed of 40 parts by mass of n-butyl acrylate, 58 parts by mass of methyl methacrylate, and 2 parts by mass of glycidyl methacrylate, and an aqueous ammonium persulfate solution (concentration: 2% by mass) with stirring in a reaction vessel heated to 80 ° C. 15 parts by mass were dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C., and polymerized.
After completion of the dropping, the temperature in the reaction vessel was maintained at the same temperature with stirring for 60 minutes. Thereafter, the contents are cooled to 30 ° C., 3 parts by mass of γ-glycidoxypropyltrimethoxysilane is added with stirring, and the mixture is adjusted with deionized water so that the solid content concentration becomes 35.0% by mass. And filtering with a 100 mesh wire netting to obtain a comparative aqueous resin composition. The light transmittance of the mixed liquid obtained by mixing the obtained aqueous resin composition (VIII) and tetrahydrofuran was 3.5%.

[Comparative Example 4]
Urethane resin obtained in Reference Example 1, 140 parts by mass of deionized water in a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, dropping funnel for dropping monomer mixture, dropping funnel for dropping polymerization catalyst 100 parts by mass of the aqueous dispersion (a1-1) was added, and the temperature was raised to 80 ° C. while blowing nitrogen.

A monomer mixture consisting of 40 parts by mass of n-butyl acrylate, 58 parts by mass of methyl methacrylate, and 2 parts by mass of γ-methacryloxypropyltrimethoxysilane with stirring in a reaction vessel heated to 80 ° C., and an aqueous ammonium persulfate solution ( (Concentration: 2% by mass) 15 parts by mass were dropped from a separate dropping funnel over 120 minutes while maintaining the temperature in the reaction vessel at 80 ± 2 ° C. to polymerize.
After completion of the dropping, the temperature in the reaction vessel was maintained at the same temperature with stirring for 60 minutes. Thereafter, the contents were cooled to 30 ° C., adjusted with deionized water so that the solid content concentration was 35.0% by mass, and filtered through a 100 mesh wire net to obtain a comparative aqueous resin composition. The light transmittance of the mixed liquid obtained by mixing the obtained aqueous resin composition (IX) and tetrahydrofuran was 55.9%.

[Comparative Example 5]
Add 30 parts by weight of deionized water to a pre-emulsion mixing container, add 4 parts by weight of emulsifier Neugen XL-400 (Daiichi Kogyo Seiyaku Co., Ltd .; polyoxyethylene decyl ether, solid content: 100% by weight) and stir. And dissolved. A monomer component of 40 parts by mass of n-butyl acrylate, 58 parts by mass of methyl methacrylate, and 2 parts by mass of dimethylaminoethyl methacrylate was sequentially added to the container and stirred to prepare a pre-emulsion of the monomer mixture.

In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 100 parts by mass of deionized water was added, and the temperature was raised to 80 ° C. while blowing nitrogen. Acrylic polymer (X) was produced by adding 0.3 part of ammonium persulfate under stirring, and then dropping and polymerizing the pre-emulsion of the monomer mixture over 120 minutes while maintaining at 80 ± 2 ° C. .
After completion of the dropping, the temperature in the reaction vessel was maintained at the same temperature with stirring for 60 minutes. Thereafter, the content was cooled to 30 ° C., 100 parts by mass of the urethane resin aqueous dispersion of Reference Example 1 and 3 parts by mass of γ-glycidoxypropyltrimethoxysilane were added, and after stirring and mixing, the solid content concentration was It adjusted with deionized water so that it might become 35.0 mass%, and the aqueous resin composition for a comparison was obtained. The light transmittance of the mixed liquid obtained by mixing the obtained aqueous resin composition (X) and tetrahydrofuran was 45.3%.

Tables 1 and 2 below show the evaluation of Examples and Comparative Examples. The abbreviations in the table are also as described below.
BA; n-butyl acrylate MMA; methyl methacrylate DMAEMA; dimethylaminoethyl methacrylate GMA; glycidyl methacrylate Z-6030; γ-methacryloxypropyltrimethoxysilane Z-6040 manufactured by Toray Dow Corning Co., Ltd .; Γ-glycidoxypropyltrimethoxysilane Z-6043 manufactured by Toray Dow Corning Co., Ltd. 2- (3 ′, 4′-epoxycyclohexyl) ethyltrimethoxysilane

Claims (7)

Core-shell type resin particles (A), wherein the shell layer is made of a urethane resin (a1) having a carboxyl group and the core layer is made of a vinyl polymer (a2) having a basic nitrogen atom-containing group, hydrolyzable silyl groups or An aqueous resin composition comprising a compound (B) having a silanol group and an epoxy group, and an aqueous medium, wherein the core-shell type resin particles (A) are dispersed in the aqueous medium. object. The aqueous resin composition according to claim 1, wherein the vinyl polymer (a2) further has a hydrolyzable silyl group or a silanol group. The water-based resin composition of Claim 1 whose mass ratio [(a1) / (a2)] of the said urethane resin (a1) and the said vinyl polymer (a2) is 10 / 90-70 / 30. The aqueous resin composition according to claim 1, wherein the urethane resin (a1) is obtained by reacting a polyol containing a carboxyl group-containing polyol with a polyisocyanate. The aqueous resin composition of Claim 1 whose acid value derived from the carboxyl group which the said urethane resin (a1) has is 10-50. The aqueous resin composition according to claim 1, wherein the vinyl polymer (a2) has 10 to 700 mmol / Kg of a basic nitrogen atom-containing group with respect to the total amount of the vinyl polymer (a2). A coating agent comprising the aqueous resin composition according to claim 1.