JP6186994B2 - Acrylic resin composition - Google Patents

Description

  The present invention relates to an acrylic resin composition.

Conventionally, unsaturated polyester resins, epoxy resins, polyurethane resins, and the like are used as coating agents for forming a coating film on a substrate such as a floor surface, a wall surface, or a road pavement surface.
Although the unsaturated polyester resin is excellent in solvent resistance, it is inferior in weather resistance, has a large shrinkage at the time of curing, and has poor low temperature workability.
Epoxy resins have excellent alkali resistance and excellent adhesion to a substrate, but have poor weather resistance, a long curing time, and poor curability at low temperatures.
Polyurethane resins are excellent in elasticity and flexibility, but are inferior in chemical resistance and weather resistance.
Also, vinyl ester resins and acrylic resins that are excellent in low-temperature curability, weather resistance, and chemical resistance are often used as coating agents.
Since vinyl ester resins and acrylic resins have a specific odor caused by low molecular weight monomers such as styrene and methyl methacrylate, the odor during operation is a problem.

In recent years, interest in environmental problems has increased, and coating agents containing volatile and strong odor components such as organic solvents and low molecular weight monomers tend to be refrained from use.
In order to solve such a problem, a syrup composition containing a monomer having a molecular weight of 130 to 300 and a resin having a glass transition temperature of 20 to 155 ° C. has been proposed (for example, Patent Document 1). According to the invention of Patent Document 1, odor is reduced.
Moreover, in order to improve durability, the syrup composition (for example, patent document 2) containing the acryl-type monomer which does not have an alicyclic structure, and the polymer which has a double bond, has a polymerizable double bond A resin composition (for example, Patent Document 3) containing a (meth) acrylic polymer and a polymerizable monomer has been proposed.

JP 2007-224264 A JP 2009-161589 A Japanese Patent Laid-Open No. 2002-20440

By the way, the resin compositions as described in Patent Documents 1 to 3 are generally applied to a dry substrate (dry substrate).
When a conventional resin composition is applied to a wet substrate, the coating film, which is a cured product of the resin composition, has insufficient adhesion to the substrate. In particular, in the case of a substrate having a complicated uneven surface or a substrate having a crack on the surface, since the moisture exists in the depressions or cracks, the resin composition is difficult to penetrate into the substrate, and adhesion of the obtained coating film Sex was easy to fall.
Furthermore, the adhesiveness when affected by moisture from the base material was remarkably lowered.
Moreover, since the resin compositions described in Patent Documents 1 and 3 have a low Tg of the polymer, there is a problem that the durability at high temperatures is poor, and the resin composition of Patent Document 2 has a low flash point. There was a problem that it was difficult to handle due to the limited storage quantity.

  The present invention has been made in view of the above circumstances, and even when applied to a wet substrate, it can form a coating film excellent in adhesion to the substrate and durability at high temperatures, and is flammable. An object of the present invention is to provide an acrylic resin composition having a high point and excellent handleability.

The acrylic resin composition of the present invention comprises a monomer (A) having one (meth) acryloyl group in the molecule, and a monomer (B) having two or more (meth) acryloyl groups in the molecule. ), A polymer (C) having a polymerizable double bond and 75% by mass or more of a methyl methacrylate unit, and a wax (D), the monomer (A) as a furan ring, It contains a (meth) acrylate (a1) having a heterocycle selected from the group consisting of a hydrofuran ring, a pyran ring and a hydropyran ring, a hydroxyalkyl (meth) acrylate (a2), and a methyl methacrylate (a3). And
It is preferable to contain 1-15 mass% of said polymers (C) with respect to a total of 100 mass% of said monomer (A), said monomer (B), and said polymer (C).

In the present specification, “(meth) acryl” is a general term for acrylic and methacrylic. “(Meth) acrylate” is a general term for acrylate and methacrylate. The “(meth) acryloyl group” is a general term for an acryloyl group and a methacryloyl group, and the general formula CH ₂ ═C (R) —C (═O) — [R represents a hydrogen atom or a methyl group. ].
“Acrylic” is a generic term for acrylic and methacrylic.

  The acrylic resin composition of the present invention can form a coating film excellent in adhesion to a substrate and durability at high temperatures, even when applied to a wet substrate, has a high flash point and is easy to handle. It is excellent.

(Acrylic resin composition)
The acrylic resin composition of the present invention contains a monomer (A), a monomer (B), a polymer (C), and a wax (D).

Although the viscosity of an acrylic resin composition is not specifically limited, 300 mPa * s or less is preferable and 5-100 mPa * s is more preferable. The lower the viscosity of the acrylic resin composition, the better the workability. In addition, the lower the viscosity, the higher the adhesion to the wet substrate, and the higher the permeability to the substrate, the higher the anchor effect to the substrate and the higher the durability when heat is applied. .
The viscosity of the acrylic resin composition is a solution viscosity measured with a Brookfield viscometer BM type defined in JIS-Z8803 at 23 ° C.

The acrylic resin composition has a contact angle with a glass plate at 23 ° C. (JIS R3202: 2011, float plate glass described in “Float plate glass and polished plate glass”), preferably less than 35 °, more preferably less than 20 °. is there. This is because the permeability of the acrylic resin composition to the base material is better if the upper limit value or less.
In addition, a contact angle with a float plate glass is adjusted by adjusting the kind and content of monomer (a1)-(a3) mentioned later.

70 degreeC or more is preferable and, as for the glass transition temperature (Tg) of the hardened | cured material of an acrylic resin composition, 70-120 degreeC is more preferable. If it is more than the said lower limit, durability with respect to the heat | fever of the hardened | cured material of an acrylic resin composition can be improved. If it is below the said upper limit, the hardened | cured material of an acrylic resin composition will not become hard too much, and even when the motion of a base material generate | occur | produces with time by temperature change, degradation of a coating film can be suppressed.
Tg of the cured product of the acrylic resin composition is obtained by polymerizing and curing the acrylic resin composition to prepare a cast plate having a thickness of 1 mm, and measuring the viscoelasticity (JIS-K7244-2: 1998, This is the Tg when the “Plastic—Dynamic Mechanical Properties Test Method—Part A: Method A” described in “Torsion Pendulum Method” is used.
In addition, Tg of hardened | cured material is adjusted by adjusting the kind and content of the monomer (a1)-(a3), monomer (B), and polymer (C) which are mentioned later.

The flash point of the acrylic resin composition is preferably 21 ° C. or higher. This is because the handling is easy if the lower limit is exceeded.
The flash point is adjusted by adjusting the types and contents of the monomers (a1) to (a3) and the monomer (B) described later.

<Monomer (A)>
The monomer (A) is a monomer having one (meth) acryloyl group in the molecule. The acrylic resin composition has a (meth) acrylate (a1) (hereinafter, monomer (A)) having a heterocycle selected from the group consisting of a furan ring, a hydrofuran ring, a pyran ring and a hydropyran ring as the monomer (A). a1)), hydroxyalkyl (meth) acrylate (a2) (hereinafter sometimes referred to as monomer (a2)), and methyl methacrylate (a3) (hereinafter referred to as monomer (a3)). At least).

≪Monomer (a1) ≫
The monomer (a1) is a (meth) acrylate having only one (meth) acryloyl group in the molecule and a heterocycle selected from the group consisting of a furan ring, a hydrofuran ring, a pyran ring and a hydropyran ring. .
A monomer (a1) is a component which adjusts characteristics, such as the viscosity of an acrylic resin composition, the mechanical strength of a coating film, flash point temperature, and Tg.

Examples of the (meth) acrylate having a furan ring include furyl (meth) acrylate and furfuryl (meth) acrylate.
Examples of the (meth) acrylate having a hydrofuran ring include tetrahydrofuryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl (meth) acrylate, and the like.
Examples of the (meth) acrylate having a pyran ring include pyranyl (meth) acrylate.
Examples of the (meth) acrylate having a hydropyran ring include dihydropyranyl (meth) acrylate, tetrahydropyranyl (meth) acrylate, dimethyldihydropyranyl (meth) acrylate, and dimethyltetrahydropyranyl (meth) acrylate. Among these monomers (a1), those having a molecular weight of 130 to 300 are preferable, and tetrahydrofurfuryl methacrylate, caprolactone-modified tetrahydrofurfuryl (meth) acrylate, dimethyldihydropyranyl methacrylate, and dimethyltetrahydropyranyl methacrylate are more preferable.
These monomers (a1) may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the monomer (a1) in the acrylic resin composition is determined in consideration of the type of the monomer (a1) and the like. For example, the monomer (A) and the monomer (B) 10-60 mass% is preferable with respect to a total of 100 mass% with a polymer (C), and 15-60 mass% is more preferable. If it is more than the said lower limit, the surface curability of an acrylic resin composition and the intensity | strength of a coating film will improve, and the flash point of an acrylic resin composition can be raised. If it is below the said upper limit, Tg of the hardened | cured material which superposed | polymerized and hardened the acrylic resin composition can be raised.

≪Monomer (a2) ≫
The monomer (a2) is a hydroxyalkyl (meth) acrylate having one (meth) acryloyl group and one or more hydroxyalkyl groups.
A monomer (a2) is a component which provides the adhesiveness with respect to a base material.

Examples of the monomer (a2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, and hydroxyhexyl (meth) acrylate. , Hydroxyheptyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxynonyl (meth) acrylate, hydroxydecyl (meth) acrylate, hydroxyundecyl (meth) acrylate, hydroxydodecyl (meth) acrylate, and the like. Among these, those having a molecular weight of 130 to 300 are preferable, and 2-hydroxyethyl methacrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate are particularly preferable.
These monomers (a2) may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the monomer (a2) in the acrylic resin composition is determined in consideration of the type of the monomer (a2) and the like. For example, the monomer (A) and the monomer (B) 2-40 mass% is preferable with respect to a total of 100 mass% with a polymer (C). If it is more than the said lower limit, sufficient adhesiveness can be provided to a coating film. In addition, since affinity for the substrate can be imparted, the affinity for moisture in the wet substrate is improved. Therefore, it is possible to form a coating film excellent in adhesiveness not only on a dry substrate but also on a wet substrate. In particular, even if the substrate has a complicated surface state or a substrate having cracks on the surface, the acrylic resin composition easily penetrates into the substrate, so the adhesion between the substrate and the coating film is improved. . Furthermore, the surface curability of the acrylic resin composition and the strength of the coating film are improved, and the flash point of the acrylic resin composition can be increased. If it is below the said upper limit, the water resistance of a coating film will become favorable.

≪Monomer (a3) ≫
The monomer (a3) is methyl methacrylate.
The content of the monomer (a3) in the acrylic resin composition is determined in consideration of the type of the monomer (a2) and the like. For example, the monomer (A) and the monomer (B) 5-25 mass% is preferable with respect to a total of 100 mass% with a polymer (C), and 5-20 mass% is more preferable. If it is more than the said lower limit, the surface curability of an acrylic resin composition and the intensity | strength of a coating film can be improved. If it is below the said upper limit, the flash point of a resin composition can be raised.

≪Other monomers≫
The acrylic resin composition is a monomer having only one (meth) acryloyl group in addition to the monomers (a1) to (a3) as the monomer (A) (hereinafter, monomer (a4)). May be contained within a range that does not impair mechanical properties such as the strength of the coating film, flash point temperature, and Tg.
As the monomer (a4), monomers having various molecular weights can be used, but those having a molecular weight of 130 to 300 are preferable.

  Examples of the monomer (a4) having a molecular weight of 130 to 300 include n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, and nonyl. Alkyl groups having 4 to 15 carbon atoms such as (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, etc. Alkyl (meth) acrylate having succinic acid 2- (meth) acryloyloxyethyl maleate, 2- (meth) acryloyloxyethyl maleate, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) hexahydrophthalic acid Carboxylic acid-containing (meth) acrylates such as acryloyloxyethyl; 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, 3-methacryloyloxypropyl acid phosphate, dibutyl 2- (meth) acryloyloxyethyl acid phosphate, Phosphoric acid ester monomers such as dioctyl 2- (meth) acryloyloxyethyl phosphate, diphenyl 2- (meth) acryloyloxyethyl phosphate, (meth) acryloyloxyethyl polyethylene glycol acid phosphate; ethylene glycol monomethyl ether methacrylate , Ethylene glycol monoethyl ether methacrylate, diethylene glycol monomethyl ether (meta Oligoethylene glycol monoalkyl ether such as acrylate, diethylene glycol monoethyl ether (meth) acrylate, 2-ethoxylated 2-ethylhexyl (meth) acrylate, polyethylene glycol monomethyl ether (meth) acrylate, polyethylene glycol monoethyl ether (meth) acrylate (Meth) acrylate; glycidyl group-containing methacrylate such as glycidyl methacrylate; polyethylene glycol mono (meth) acrylate (ethylene glycol repeat number is 4 or less), polypropylene glycol mono (meth) acrylate (polypropylene glycol repeat number is 2 or less), etc. Hydroxyl-terminated polyalkylene glycol mono (meth) acrylate; trifluoroethyl (meth) acrylate Fluorine-containing (meth) acrylates such as acrylate and tetrafluoroethyl (meth) acrylate; di- or trialkylcyclohexyl group-containing (meth) acrylates such as dimethylcyclohexyl (meth) acrylate and trimethylcyclohexyl (meth) acrylate; vinyltrichlorosilane; Silane coupling agents such as vinyltris (β-methoxyethoxy) silane and γ-methacryloxypropyltrimethoxysilane; Di- or trialkylphenyl group-containing (meth) acrylates such as dimethylphenyl (meth) acrylate and trimethylphenyl (meth) acrylate Benzyl methacrylate, isobornyl methacrylate, dicyclopentenyloxyethyl (meth) acrylate, phenoxyethyl methacrylate, phenoxydiethyl Glycol (meth) acrylate, phenoxytriethylene glycol (meth) acrylate, and the like.

  Examples of the monomer (a4) having a molecular weight of less than 130 include methyl acrylate, ethyl (meth) acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, (meth) acrylic acid, and allyl (meth). An acrylate etc. are mentioned.

Examples of the monomer (a4) having a molecular weight exceeding 300 include stearyl (meth) acrylate, cetyl methacrylate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, octafluoropentyl methacrylate, heptadecafluorodecyl (meth) ) Acrylate, polyethylene glycol mono (meth) acrylate (ethylene glycol repeat number is 5 or more), polypropylene glycol mono (meth) acrylate (polypropylene glycol repeat number is 3 or more), etc. hydroxyl-terminated polyalkylene glycol mono (meth) acrylate Polyalkylene glycol monoalkyl ethers such as polyethylene glycol monomethyl ether (meth) acrylate (ethylene glycol repeat number of 5 or more) ) Acrylate, and the like.
The upper limit of the molecular weight is not particularly limited, but is preferably 1,000 or less.

  Content of the monomer (a4) in an acrylic resin composition is 0-30 mass with respect to a total of 100 mass% of a monomer (A), a monomer (B), and a polymer (C). % Is preferable, and 0 to 25% by mass is more preferable. If it is below the said upper limit, compatibility with a polymer (C) will not be impaired.

  The content of the monomer (A) in the acrylic resin is 55 to 87% by mass with respect to a total of 100% by mass of the monomer (A), the monomer (B) and the polymer (C). Preferably, 65-85 mass% is more preferable. If it is more than the said lower limit, the viscosity of an acrylic resin composition will not become high too much, and workability | operativity will become favorable. If it is below the said upper limit, the viscosity of an acrylic resin composition will not become low too much, and it can apply with moderate thickness with respect to a base material.

<Monomer (B)>
The monomer (B) is a polyfunctional monomer having two or more (meth) acryloyl groups in the molecule.
The monomer (B) improves the mechanical strength, abrasion resistance, chemical resistance and the like of the coating film.

Examples of the monomer (B) include ethylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,3-butanediol di ( (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, poly (Poly) alkylene such as butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,4-cyclohexanedimethanol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate Glycol di (meth) acrylate; bisphenol A ethylene oxide adduct di (meth) acrylate, bisphenol A propylene oxide adduct di (meth) acrylate, bisphenol A diglycidyl ether (meth) acrylic acid adduct, etc. (Meth) acrylate; trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris (2- (meth) acryloyloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) And polyfunctional monomers having three or more (meth) acryloyl groups in the molecule such as acrylate.
As the monomer (B), ethylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,3-butanediol di (meth) ) Acrylate, 1,6-hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,4-cyclohexanedimethanol di (meth) ) Acrylate, bisphenol A ethylene oxide adduct di (meth) acrylate, bisphenol A propylene oxide adduct di (meth) acrylate, and bisphenol A diglycidyl ether (meth) acrylic acid adduct are preferred.
These monomers (B) may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the monomer (B) in the acrylic resin composition is 0.5 to 100% by mass with respect to a total of 100% by mass of the monomer (A), the monomer (B), and the polymer (C). 15 mass% is preferable and 1-15 mass% is more preferable. If it is more than the said lower limit, the mechanical strength of a coating film, abrasion resistance, durability, etc. can be improved more. If it is below the said upper limit, the time until hardening will not become too short, but workability | operativity will become favorable.
In addition, the content of the monomer (B) in the acrylic resin composition is the following (in the total of 100% by mass of the monomer (A), the monomer (B), and the polymer (C) ( 1) It is preferably within the range that satisfies the formula. If the following formula (1) is satisfied, a coating film excellent in balance between mechanical strength and flexibility can be formed.

0.25 <content of monomer (B) / T <7.5 (1)
(1) In the formula, “content of monomer (B)” means the monomer (B) relative to 100% by mass of the total of monomer (A), monomer (B) and polymer (C). ) Content (mass%). “T” is the total number of carbon atoms in the monomer (B) (excluding the carbon of the (meth) acryloyl group).

<Polymer (C)>
The polymer (C) is a polymer having a polymerizable double bond and having 75% by mass or more of methyl methacrylate units. The polymer (C) has a polymerizable double bond involved in a radical polymerization reaction such as a vinyl group, an allyl group, or a (meth) acryloyl group, and imparts curability to the acrylic resin composition. It is a component that imparts mechanical strength to the cured coating film of the resin composition.
As the polymer (C), those having a methyl methacrylate unit are preferable. Other than methyl methacrylate units, for example, units having an alkyl group having 2 or more carbon atoms, alkyl (meth) acrylate units, other monofunctional acrylic monomers, polyfunctional acrylic monomers, (meth) acrylic acid, etc. Can be included.
Content of the methylmethacrylate unit in a polymer (C) is 75 mass% or more, 85 mass% or more is preferable and 90 mass% or more is more preferable. The content of methyl methacrylate units in the polymer (C) is preferably 99% by mass or less, and more preferably 97% by mass or less. If it is more than the said lower limit, wet heat durability can be improved. If it is below the said upper limit, durability with respect to the heat | fever when hardening an acrylic resin composition will be improved.

Although the manufacturing method of a polymer (C) is not specifically limited, For example, the following method is mentioned.
As a first step reaction, a first functional group involved in a reaction that forms a bond such as an ester bond or a urethane bond with one or more of methyl methacrylate (c1) and another acrylic monomer (c2). The first monomer (C ′) having the first functional group is obtained by copolymerizing the monomer having the first functional group. Next, as a second stage reaction, the second functional group that reacts with the first functional group to form a bond and the second monomer having a polymerizable double bond, and the first copolymer By reacting with (C ′), a polymer (C) having a polymerizable double bond is obtained.
As a combination of the first functional group and the second functional group, a carboxyl group and a glycidyl group, a hydroxyl group and an isocyanate group, and the like are preferable.
As the monomer (c2), methyl acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, Alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate; Cycloalkyl (meth) acrylates such as isobornyl (meth) acrylate and cyclohexyl (meth) acrylate; Alkyl having 2 or more carbon atoms (meth) ) Glycidyl (meth) acrylate or (meth) acrylic acid is preferred as the acrylic unit that is not contained in either the acrylate unit or the cycloalkyl (meth) acrylate unit. These may be used individually by 1 type and may be used in combination of 2 or more type.
As a monomer constituting the polymer (C), an alkyl methacrylate and / or isobornyl (meth) having a methyl methacrylate unit of 75% by mass or more in the polymer (C) and having an alkyl group having 2 to 4 carbon atoms. It is preferable to use acrylate, glycidyl (meth) acrylate, and (meth) acrylic acid, and it is more preferable to use methyl methacrylate, glycidyl (meth) acrylate, and (meth) acrylic acid.
The alkyl methacrylate having an alkyl group having 2 to 4 carbon atoms is preferably n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, or sec-butyl methacrylate, and particularly preferably n-butyl methacrylate.

  The Tg of the first copolymer (C ′) is preferably 80 to 155 ° C., more preferably 80 to 110 ° C. When Tg is 155 ° C. or lower, the solubility of the first copolymer (C ′) obtained by the first stage reaction is good when the polymer (C) is synthesized. When Tg is 80 ° C. or higher, durability when heat is applied can be enhanced. The Tg of the first copolymer (C ′) is a value determined by a differential scanning calorimeter (hereinafter abbreviated as “DSC”).

As a polymerization method in the production of the polymer (C), for example, the following method is preferable.
A first copolymer having a carboxyl group by suspension polymerization of one or more of methyl methacrylate (c1) and other acrylic monomer (c2) and (meth) acrylic acid in the first stage reaction (C ′) is obtained. In the second stage reaction, the obtained copolymer (C ′) is added to another methyl methacrylate (c1) to form a solution, and glycidyl (meth) acrylate is esterified to the copolymer (C ′) in the solution. The polymer (C) having a polymerizable double bond is obtained by addition by a crystallization reaction.
In this case, the polymerization temperature during suspension polymerization in the first stage reaction is preferably 70 to 98 ° C., and the polymerization time is preferably about 2 to 5 hours. The reaction temperature in the second stage reaction is preferably 90 to 95 ° C., and the reaction time is preferably about 1 to 4 hours.

  The preferred composition ratio of the monomer used in the first stage reaction is 90 to 99.5% by mass of methyl methacrylate (c1), 0 to 9% by mass of other acrylic monomer (c2), (meth) The acrylic acid is preferably 0.5 to 7% by mass, and more preferably (meth) acrylic acid 1 to 4% by mass.

When suspension polymerization is performed in the first stage reaction, the suspension is preferably an aqueous suspension. It is preferable to add a dispersant to the aqueous suspension. The dispersant is not particularly limited, and examples thereof include poorly water-soluble inorganic compounds such as calcium phosphate, aluminum hydroxide, and starch silica; nonionic polymer compounds such as polyvinyl alcohol, polyethylene oxide, and cellulose derivatives; alkali poly (meth) acrylate Examples thereof include metal salts and anionic polymer compounds such as alkali metal salts of (meth) acrylic acid and methyl (meth) acrylate copolymer. The amount of the dispersant used is preferably 0.005 to 5% by mass and more preferably 0.01 to 1% by mass in the suspension.
Moreover, it is preferable to contain electrolytes, such as sodium carbonate, sodium sulfate, manganese sulfate, in the suspension at the time of suspension polymerization. By containing an electrolyte, dispersion stability can be improved. The amount of electrolyte used is not particularly limited as long as it is set appropriately.

In the suspension polymerization, a polymerization initiator is used. The polymerization initiator is not particularly limited. For example, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, bis (4-tert Organic peroxides such as -butylcyclohexyl) peroxydicarbonate; azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis-2-methylbutyronitrile. These may be used alone or in combination of two or more. The addition amount and addition method of the polymerization initiator may be set as appropriate and are not particularly limited.
It is preferable to use a chain transfer agent in the suspension polymerization. When a chain transfer agent is used, the polymerization reaction of the monofunctional acrylic monomer can be easily controlled.
A thiol compound is preferably used as the chain transfer agent. The thiol compound is not particularly limited, and examples thereof include alkyl mercaptans such as t-butyl mercaptan, n-octyl mercaptan and n-dodecyl mercaptan; aromatic mercaptans such as thiophenol thionaphthol: thioglycolic acid, thioglycolic acid thiol and the like And alkyl glycolate. What is necessary is just to set suitably the addition amount and addition method of a chain transfer agent, and it is not specifically limited.

The weight average molecular weight of the first copolymer (C ′) obtained by the first stage reaction is preferably 10,000 to 150,000, and more preferably 15,000 to 80,000. When it is at least the lower limit, the strength of the cured product tends to be sufficiently high. Workability at the time of handling an acrylic resin composition will become favorable as it is below the said upper limit.
The weight average molecular weight in the present specification is obtained by dissolving the resin in a solvent (tetrahydrofuran) and converting the molecular weight measured by gel permeation chromatography (hereinafter referred to as “GPC”) into polystyrene.

  In the second stage reaction, 100 parts by mass of the first stage copolymer (C ′) was added to 100 to 200 parts by mass of another methyl methacrylate (c1) and used for the first stage reaction (meth). It is preferable to react 0.9-1.2 mol of glycidyl (meth) acrylate with respect to 1 mol of acrylic acid, and it is more preferable to react 1.0-1.1 mol.

In the second stage reaction, an esterification catalyst can be used to advance the reaction between the first functional group and the second functional group. Examples of the esterification catalyst include amines such as triethylamine; quaternary ammonium salts such as tetraethylammonium chloride and tetrabutylammonium bromide; and phosphorus compounds such as triphenylphosphine. These may be used alone or in combination of two or more. The addition amount of the esterification catalyst may be set as appropriate and is not particularly limited.
In the second stage reaction, a polymerization inhibitor may be added. When a polymerization inhibitor is added, the second stage reaction can be performed more stably. Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, 2,6-di-t-butyl 4-methylphenol, and the like. These polymerization inhibitors may be used individually by 1 type, and may be used in combination of 2 or more type. The addition amount of the polymerization inhibitor may be set as appropriate and is not particularly limited.

The polymer (C) obtained by the second stage reaction has a polymerizable double bond, that is, the carboxyl group contained in the first copolymer is glycidyl group of glycidyl (meth) acrylate by the second stage reaction. It can be confirmed that the acid value of the polymer (C) having a polymerizable double bond is less than the value estimated from the (meth) acrylic acid used in the first stage reaction. The acid value (unit: mgKOH / g) is preferably 1 or less, and more preferably 0.5 or less.
The value of the acid value in the present specification is a value obtained by dissolving the polymer (C) in toluene and titrating with 0.1N KOH ethanol solution using phenolphthalein as an indicator.

Content of the polymer (C) in an acrylic resin composition is 1-15 mass with respect to a total of 100 mass% of a monomer (A), a monomer (B), and a polymer (C). % Is preferable, and 1 to 10% by mass is more preferable. When it is at least the above lower limit, good curability is easily obtained, and when it is at most the above upper limit, the viscosity of the acrylic resin composition can be lowered.
In addition, the content of the polymer (C) in the acrylic resin composition is preferably in a range that satisfies the relationship of the following formula (2).

  150,000 ≦ [Mw of the first copolymer (C ′) obtained by the first stage reaction] × [mass% of the polymer (C) having a polymerizable double bond] ≦ 750,000 (2)

  When the polymer (C) is a mixture of the polymers (C1), (C2)... Having a polymerizable double bond, the following formula (3) is used.

  150,000 ≦ {[Mw of the first copolymer (C′1) obtained by the first stage reaction] × [mass% of the polymer (C1) having a polymerizable double bond]} + {[ Mw of first copolymer (C′2) obtained by the first stage reaction] × [mass% of polymer (C2) having a polymerizable double bond]} +... ≦ 750,000 ... (3)

  By setting it to 150,000 or more in the above formula (2) or (3), better curability can be obtained, and by setting it to 750,000 or less, the viscosity of the acrylic resin composition is lowered, and workability is improved. Can be enhanced. If the viscosity of the acrylic resin composition becomes too high, the adhesiveness of the substrate in a wet state is likely to be reduced, and the permeability to the substrate is reduced. Durability when added tends to decrease.

<Wax (D)>
The wax (D) has an effect of improving the surface curability using an air blocking effect.
Examples of the wax (D) include solid waxes. Examples of solid waxes include higher fatty acids such as paraffins, polyethylenes, and stearic acid. Among these, paraffins are preferable.

The melting point of the wax (D) is preferably 40 to 80 ° C. If it is more than the said lower limit, when an acrylic resin composition is hardened, sufficient air barrier action will be obtained and surface curability will become favorable. If it is below the said upper limit, when preparing an acrylic resin composition, the solubility of the wax (D) to a monomer (A) and (B) will become favorable.
As the wax (D), it is preferable to use two or more different melting points in combination. When two or more kinds of waxes (D) having different melting points are used in combination, even if the base material temperature is changed when the acrylic resin composition is cured, a sufficient air blocking action is obtained, and the surface curability is improved. When using together, it is preferable to use together the thing of 5 to 20 degreeC difference in melting | fusing point.

As wax (D), you may use the wax (D) disperse | distributed to the organic solvent at the point which improves surface curability. At this time, the particle diameter of the wax (D) in the dispersed state is preferably 0.1 to 50 μm. Since the wax (D) is in a dispersed state in an organic solvent and the particle diameter of the dispersed wax (D) is finely divided to 0.1 μm to 50 μm, an air blocking action can be effectively expressed. The wax (D) in the dispersed state is commercially available, and the wax may be added as it is. In this case, the acrylic resin composition of the present invention contains an organic solvent.
The wax (D) in a dispersed state may be one in which the wax (D) is dispersed in the monomers (A) and (B) without containing any organic solvent.

  The content of the wax (D) in the acrylic resin composition is such that the monomer (A), the monomer (B), and the polymer (C) are in view of the balance between the air curability and the physical properties of the coating film. ) To 100 parts by mass in total, and preferably 0.05 to 3 parts by mass, more preferably 0.05 to 2 parts by mass. If it is more than the said lower limit, when an acrylic resin composition is paint-hardened, sufficient air blocking action will be obtained and surface curability will become favorable. If it is below the above upper limit value, the storage stability of the acrylic resin composition and the stain resistance when the acrylic resin composition is coated and cured are good.

<Organic peroxide (E)>
The acrylic resin composition may contain an organic peroxide (E) as an optional component. The organic peroxide (E) serves as a polymerization initiator.
Examples of the organic peroxide (E) include ketone peroxides such as methyl ethyl ketone peroxide; 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t- Peroxyketals such as hexylperoxy) cyclohexane and 1,1-di (t-butylperoxy) cyclohexane; 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, p-menthane hydro Hydroperoxides such as peroxides; Dialkyl peroxides such as dicumyl peroxide and di-t-butyl peroxide; Diacyl peroxides such as dilauroyl peroxide and dibenzoyl peroxide; Di (4-t-butylcyclohexyl) Peroxydicarbonate Peroxydicarbonates such as di (2-ethylhexyl) peroxydicarbonate; peroxyesters such as t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxybenzoate Etc.
As the organic peroxide (E), dibenzoyl peroxide and hydroperoxide are preferable.
An organic peroxide (E) may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the organic peroxide (E) in the acrylic resin composition is preferably 0.25 to 5 parts by mass with respect to 100 parts by mass of the resin composition excluding the organic peroxide (E). 0.25-4 mass parts is more preferable. If it is more than the said lower limit, it exists in the tendency for sclerosis | hardenability to become favorable. If it is below the upper limit, the coating workability of the acrylic resin composition and the various physical properties of the resulting coating film tend to be further increased.
The content of the organic peroxide (E) in the acrylic resin composition is preferably adjusted as appropriate so that the pot life of the acrylic resin composition is 5 to 90 minutes. Thus, by adjusting and adding content of organic peroxide (E), a polymerization reaction is started immediately after addition and hardening of an acrylic resin composition advances.

<Decomposition accelerator (F)>
The acrylic resin composition may contain a decomposition accelerator (F) as an optional component. The decomposition accelerator (F) promotes the decomposition of the organic peroxide (E) and promotes the curing reaction.
As the decomposition accelerator (F), at least one selected from polyvalent metal soap (f1) and tertiary amine (f2) is preferable, and polyvalent metal soap (f1) and tertiary amine (f2) are used in combination. Is more preferable.
By using the polyvalent metal soap (f1) and the tertiary amine (f2) in combination as the decomposition accelerator (F), the curing time of the acrylic resin composition can be shortened and the curability can be enhanced. Accordingly, a coating film having excellent curability can be formed not only on a dry substrate but also on a wet substrate.

≪Polyvalent metal soap (f1) ≫
Examples of the polyvalent metal soap (f1) include cobalt naphthenate, cobalt octylate, cobalt acetoacetylate, manganese naphthenate, nickel octylate and the like.
As the polyvalent metal soap (f1), cobalt naphthenate and cobalt octylate are preferable from the viewpoint of obtaining an appropriate pot life and good curability.
A polyvalent metal soap (f1) may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the polyvalent metal soap (f1) in the acrylic resin composition is 0.000 with respect to a total of 100 parts by mass of the monomer (A), the monomer (B), and the polymer (C). More than 01 parts by mass, preferably 0.03 parts by mass or more, and more preferably 0.05 parts by mass or more. If it is more than the said lower limit, favorable curability can be obtained.
However, if the content of the polyvalent metal soap (f1) is too large, the amount of the solvent in which the polyvalent metal soap (f1) is dispersed and dissolved increases, and the curability decreases or the strength of the cured coating film increases. It may decrease. Therefore, the upper limit of the content of the polyvalent metal soap (f1) is 1.0 mass relative to 100 mass parts in total of the monomer (A), the monomer (B), and the polymer (C). Part or less, preferably 0.5 part by weight or less, more preferably 0.4 part by weight or less.
In addition, in this invention, "content of polyvalent metal soap (f1)" is content of the metal originating in a polyvalent metal soap (f1), ie, a metal conversion value.

≪Tertiary amine (f2) ≫
As the tertiary amine (f2), N, N-substituted anilines such as aniline, N, N-dimethylaniline, N, N-diethylaniline, N, N-bis (hydroxyethyl) aniline, diethanolaniline, etc .; p-toluidine , M-toluidine, N, N-dimethyl-p-toluidine, N, N-bis (2-hydroxyethyl) -p-toluidine, N, N-bis (2-hydroxypropyl) -p-toluidine, N-ethyl N, N-substituted p-toluidine such as m-toluidine; 4- (N, N-dimethylamino) benzaldehyde, 4- [N, N-bis (2-hydroxyethyl) amino] benzaldehyde, 4- (N 4- (N, N-substituted amino) benzaldehydes such as -methyl-N-hydroxyethylamino) benzaldehyde; triethanolamine, die Aliphatic amines such as Rentoriamin; pyridine, phenyl morpholine, cyclic amines such as piperidine.

  As the tertiary amine (f2), an aromatic tertiary amine is preferable. As the aromatic tertiary amine, those in which at least one aromatic residue is directly bonded to the nitrogen atom are preferable. Examples of the aromatic tertiary amine include N, N-dimethyl-p-toluidine, N, N-diethylaniline, N, N-diethyl-p-toluidine, N- (2-hydroxyethyl) N-methyl-p-. Toluidine, N, N-di (2-hydroxyethyl) -p-toluidine, N, N-di (2-hydroxypropyl) -p-toluidine; N, N-di (2-hydroxyethyl) -p-toluidine or N, N-di (2-hydroxypropyl) -p-toluidine ethylene oxide or propylene oxide adduct, N, N-dimethylaniline, N, N-diethylaniline, N, N-bis (hydroxyethyl) aniline, Examples include diethanolaniline. Moreover, it is not limited to p (para) body, o (ortho) body and m (meta) body may be sufficient.

Examples of the aromatic tertiary amine include N, N-dimethyl-p-toluidine, N, N-diethyl-p-toluidine, N, N-di (2) from the viewpoint of the reactivity and curability of the acrylic resin composition. -Hydroxyethyl) -p-toluidine and N, N-di (2-hydroxypropyl) -p-toluidine are preferred.
A tertiary amine (f2) may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the tertiary amine (f2) in the acrylic resin composition is such that the monomer (A), the monomer (B), and the weight of the tertiary amine (f2) are heavy from the viewpoint of balance between curability and pot life (workability). 0.05-10 mass parts is preferable with respect to 100 mass parts in total with coalescence (C), 0.2-8 mass parts is more preferable, and 0.2-5 mass parts is especially preferable. If it is more than the said lower limit, the surface curability of an acrylic resin composition will become favorable. If it is less than or equal to the above upper limit value, it becomes an appropriate pot life when working in a low temperature atmosphere.

<Other optional components>
The acrylic resin composition of the present invention may contain components other than the components described above as long as the effects of the present invention are not impaired.
Examples of other components include a plasticizer, a silane coupling agent, a polymerization inhibitor, a resin having no polymerizable double bond, an isocyanate prepolymer, an epoxy resin, an oligomer, and an antifoaming agent.

≪Plasticizer≫
The plasticizer is blended for the purpose of softening the coating film and reducing shrinkage during curing.
Plasticizers include phthalates such as dibutyl phthalate, di-2-ethylhexyl phthalate and diisodecyl phthalate, adipates such as di-2-ethylhexyl adipate and octyl adipate, dibutyl sebacate and di-2-ethylhexyl seba. Examples include dibasic fatty acid esters such as sebacic acid esters such as cate, azelain esters such as di-2-ethylhexyl azelate and octyl azelate; and paraffins such as chlorinated paraffin.
A plasticizer may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the plasticizer in the acrylic resin composition is preferably 10 parts by mass or less with respect to 100 parts by mass in total of the monomer (A), the monomer (B), and the polymer (C). If it is below the said upper limit, cure shrinkage of an acrylic resin composition will be suppressed, and Tg of a coating film will not fall too much.

≪Silane coupling agent≫
A silane coupling agent plays the role which stabilizes the adhesiveness with respect to a base material, and provides durability of adhesive strength.
Examples of the silane coupling agent include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane other than vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane and γ-methacryloxypropyltrimethoxysilane, γ-glu Sidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and the like can be mentioned.
The content of the silane coupling agent in the acrylic resin composition is 10 parts by mass or less with respect to 100 parts by mass in total of the monomer (A), the monomer (B), and the polymer (C). Preferably, 5 mass parts or less are more preferable from the viewpoint of curability and cost. If content of a silane coupling agent is below the said upper limit, surface curability will become favorable, hold | maintaining stabilization of the adhesiveness to the base material of an acrylic resin composition.

≪Polymerization inhibitor≫
The polymerization inhibitor is blended for the purpose of improving the storage stability of the acrylic resin composition and adjusting the polymerization reaction.
Examples of the polymerization inhibitor include hydroquinone, 2-methylhydroquinone, hydroquinone monomethyl ether, 2-6-di-t-butyl 4-methylphenol, and the like.
The content of the polymerization inhibitor in the acrylic resin composition is 0.001 to 0.00 with respect to 100 parts by mass in total of the monomer (A), the monomer (B), and the polymer (C). 2 parts by mass is preferable, and 0.002 to 0.18 parts by mass is more preferable.

≪Resin without polymerizable double bond≫
As resin which does not have a polymerizable double bond, that whose Tg is 20-155 degreeC is preferable, and what is 20-105 degreeC is more preferable.
If Tg is below the said upper limit, when manufacturing an acrylic resin composition, the solubility to a monomer (A) and (B) will become favorable.
In addition, Tg of resin which does not have a polymerizable double bond is the value calculated | required by the measurement of DSC.

Moreover, 10,000-150,000 are preferable and, as for the weight average molecular weight (Mw) of resin which does not have a polymerizable double bond, 10,000-80,000 are more preferable. If it is more than the said lower limit, the coating-film intensity | strength of an acrylic resin composition can be improved more. If it is below the said upper limit, when preparing an acrylic resin composition, the solubility to a monomer (A) and (B) will become favorable.
The Mw of the resin having no polymerizable double bond is obtained by dissolving the resin in a solvent (tetrahydrofuran) and converting the molecular weight measured by gel permeation chromatography (hereinafter referred to as “GPC”) into polystyrene.

Examples of the resin having no polymerizable double bond include alkyl (meth) acrylate homopolymers or copolymers, cellulose acetate butyrate resin, diallyl phthalate resin, saturated polyester resin, and the like.
As the resin having no polymerizable double bond, a homopolymer or copolymer of alkyl (meth) acrylate or cellulose acetate butyrate resin is preferable.
A resin having no polymerizable double bond may be used alone or in combination of two or more.

  Examples of the monomer constituting the homopolymer or copolymer of alkyl (meth) acrylate include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i -Butyl (meth) acrylate, t-butyl (meth) acrylate, amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (Meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (medium) ) Acrylate, benzyl (meth) acrylate, dicyclopentenyl (meth) acrylate, 2-dicyclopentenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, Examples include butoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid, and the like. It is done.

  The content of the resin having no polymerizable double bond is preferably 0 to 5% by mass with respect to 100 parts by mass in total of the monomer (A), the monomer (B) and the polymer (C). . If it is below the said upper limit, the viscosity of an acrylic resin composition can be adjusted, without impairing a physical property.

≪Isocyanate prepolymer≫
The isocyanate prepolymer is highly reactive and easily reacts with moisture in the air and monomer components in the acrylic resin composition. Therefore, if the acrylic resin composition contains an isocyanate prepolymer, the curing time can be further shortened.

  Examples of the isocyanate prepolymer include hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, and tetramethylene diisocyanate. , Polyisocyanurate obtained by prepolymerizing phenylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, isophorone diisocyanate, and the like.

  As for content of an isocyanate prepolymer, 0-30 mass parts is preferable with respect to a total of 100 mass parts of a monomer (A), a monomer (B), and a polymer (C). If it is below the above upper limit value, the curing time can be further shortened and the workability is improved while sufficiently securing the pot life of the acrylic resin composition.

≪Epoxy resin≫
An epoxy resin is a component which improves the adhesiveness with an inorganic base material. Therefore, if the acrylic resin composition contains an epoxy resin, adhesion to crushed stone and the like used in concrete and asphalt pavement can be improved.

Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, polysulfide modified epoxy resin and the like.
As the epoxy resin, a polysulfide-modified epoxy resin is preferable from the viewpoint of adhesion to an inorganic base material and curability. An epoxy resin may be used individually by 1 type, and 2 or more types may be used in combination.

  The content of the epoxy resin is preferably 0 to 20 parts by mass, and 0 to 10 parts by mass with respect to 100 parts by mass in total of the monomer (A), the monomer (B) and the polymer (C). More preferred. If it is below the said upper limit, hardening time can be shortened and workability | operativity becomes favorable, ensuring the pot life of an acrylic resin composition fully.

≪Oligomer≫
The oligomer is blended for the purpose of improving the surface curability.
Examples of the oligomer include urethane (meth) acrylate and polyester (meth) acrylate.
Urethane (meth) acrylate includes, for example, a hydroxyl group-containing (meth) acrylate and a polyisocyanate having two or more isocyanate groups in one molecule, and a hydroxyl group-containing (meth) acrylate having two or more isocyanate groups in one molecule. It is obtained by reacting the polyisocyanate having and the polyol having two or more hydroxyl groups in one molecule by a known method.
Polyester (meth) acrylates are polybasic acids such as phthalic acid, isophthalic acid, tetrahydrophthalic acid, succinic acid, maleic acid, fumaric acid and adipic acid or their anhydrides, and polyhydric alcohol compounds such as ethylene glycol and propylene glycol. And a (meth) acrylic acid adduct or glycidyl (meth) acrylate and a polybasic acid anhydride.
0-20 mass parts is preferable with respect to a total of 100 mass parts of a monomer (A), a monomer (B), and a polymer (C), and, as for content of an oligomer, 0-10 mass parts is more. preferable. If it is below the said upper limit, hardening time can be shortened and workability | operativity becomes favorable, ensuring the pot life of an acrylic resin composition fully.

≪Defoamer≫
Examples of the antifoaming agent include known antifoaming agents. For example, acrylic defoamers in which a special acrylic polymer is dissolved in a solvent, vinyl defoamers in which a special vinyl polymer is dissolved in a solvent, etc. : OX-880EF, OX-881, OX-883, OX-77EF, OX-710, OX-8040, 1922, 1927, 1950, P-410EF, P-420, P-425, PD-7, 1970, 230 , 230HF, LF-1980, LF-1982, LF-1983, LF-1984, LF-1985, etc.) and BYK-052, BYK-1752 manufactured by BYK Japan, Inc. can be used.
The content of the antifoaming agent is preferably 0 to 3 parts by mass, and 0 to 2 parts by mass with respect to 100 parts by mass in total of the monomer (A), the monomer (B) and the polymer (C). Is more preferable. If it is below the said upper limit, the bubble mixed when the acrylic resin composition was stirred and mixed can be removed effectively, and the coating film which a bubble does not mix can be obtained.

≪Others≫
Acrylic resin compositions may contain UV absorbers such as benzotriazole derivatives, hindered amine light stabilizers, antioxidants, leveling agents, thixotropic agents such as aerosil, and moisture resistance such as calcium carbonate, if necessary. Pigments, inorganic pigments such as chromium oxide and bengara, and organic pigments such as phthalocyanine blue may be contained.

(Method for producing acrylic resin composition)
As a manufacturing method of an acrylic resin composition, the method of mixing each component mentioned above is mentioned.
In addition, the tertiary amine (f2) in the decomposition accelerator (F) may be added immediately before the acrylic resin composition is cured, or may be added in advance to the acrylic resin composition. The polyvalent metal soap (f1) is preferably added immediately before the acrylic resin composition is cured. If the polyvalent metal soap (f1) is added to the acrylic resin composition in advance, the stability of the acrylic resin composition decreases, and the viscosity of the acrylic resin composition increases over time. The resin composition may be gelled.
Moreover, it is preferable to add a polymerization initiator just before hardening an acrylic resin composition.

  When the acrylic resin composition contains an isocyanate prepolymer, the isocyanate prepolymer is preferably added immediately before the acrylic resin composition is cured. Since the isocyanate prepolymer has high reactivity as described above, it easily reacts with moisture in the air and the monomer component in the acrylic resin composition. For this reason, if it is added to the acrylic resin composition in advance, it tends to cause the viscosity to increase or harden during the production or storage of the acrylic resin composition.

(Coating)
The coating of the present invention is obtained by forming a coating film made of a cured product of the acrylic resin composition of the present invention on the surface of a substrate.

Examples of the base material in the covering include cement concrete, asphalt concrete, mortar concrete, resin concrete, permeable concrete, ALC (lightweight foamed concrete) plate, PC (precast concrete) plate and the like. These may be used alone or in combination of two or more. Concrete may or may not contain reinforcing bars.
These base materials are used, for example, for floors and platforms of buildings, floor slabs such as roads, bridges and viaducts. For building floors, platforms, and floor slab waterproof structures, the existing base material on which building floors and pavement layers have already been formed, and the structure after the existing pavement layers and existing waterproof layers have been removed There is no particular problem even if the body is used as a base material before the undercoat layer is applied.
The shape of the substrate is not particularly limited, and may be any shape such as a flat surface, a curved surface, and an inclined surface.

The thickness of a coating film is not specifically limited, For example, it determines according to the function calculated | required by a coating.
Examples of the method for forming a coating film include a method in which the acrylic resin composition of the present invention is applied to a substrate and cured.
Examples of the coating method include a known coating method using a roller, a gold trowel, a brush, a flexible bow, a coating machine (such as a spray coating machine), and the like. When using a two-part airless coating machine, it is desirable to divide into two liquids on the main agent side and the curing agent side, add a curing accelerator on the main agent side, and add an organic peroxide on the curing agent side.

  Moreover, -30-60 degreeC is preferable and the temperature at the time of coating has especially preferable -10-40 degreeC. From the viewpoint of workability, the pot life is preferably 5 to 90 minutes, more preferably 5 to 60 minutes. The curing time is preferably 10 to 120 minutes, more preferably 10 to 90 minutes. Pot life and cure time are adjusted by adjusting the amount of organic peroxide and cure accelerator.

  The coating should just have the coating film which is the hardened | cured material of the acrylic resin composition of this invention formed in the surface of a base material. For example, a coating film that is a cured product of the acrylic resin composition of the present invention may be formed as an undercoat layer, and an intermediate coat layer and an overcoat layer may be laminated in this order on the undercoat layer. In addition, as for the coating, only the undercoat layer may be formed on the surface of the base material, or only the undercoat layer and the overcoat layer may be formed, or four or more layers including the undercoat layer may be formed. It may be laminated.

The intermediate coating layer is not particularly limited, and may be a layer made of a cured product of the acrylic resin composition of the present invention or a layer made of a cured product other than the acrylic resin composition of the present invention.
Examples of materials other than the acrylic resin composition of the present invention include solvent-based resins and emulsion-based resins, and synthetic resin-based paints that are cured after construction, such as epoxy resins, polyurethane resins, unsaturated polyester resins, and methacrylic resins; resins, rubbers In addition, a solid material such as asphalt that is melted and liquefied before coating; a liquid material such as petroleum asphalt, asphalt emulsion, and various liquid synthetic resins.
The method for forming the intermediate coating layer is appropriately determined according to the type of material constituting the intermediate coating layer.

  The top coat layer is the same as the intermediate coat layer. In addition, the topcoat layer may be a topcoat layer or a protective layer formed of a film or a sheet from the viewpoint of design properties and appearance.

In order to strengthen the adhesiveness between the undercoat layer and the intermediate coat layer, or the adhesiveness between the intermediate coat layer and the overcoat layer, an adhesive layer may be provided between the respective layers. The adhesive used for the adhesive layer is not particularly limited, and may be, for example, any of liquid, powder, granular, and sheet / film. The adhesive is not particularly limited as long as it improves the adhesion between the undercoat layer of the acrylic resin composition and the layer laminated thereon. Examples of the adhesive include solid materials such as resins, rubbers and asphalts, and liquid materials such as petroleum asphalts and asphalt emulsions and various liquid synthetic resins.
As a method for forming the adhesive layer, when the adhesive is liquid, the liquid material may be applied onto the undercoat layer by brush, roller, spray, or the like. When the adhesive is powdery or granular, the adhesive may be uniformly sprayed on the surface of the undercoat layer, or after the acrylic resin composition is applied, it may be sprayed before curing. When the adhesive is solid, it may be applied after being melted by heating and liquefying.

  Since the coating of the coating according to the present invention can prevent the occurrence of swelling caused by moisture contained in the concrete layer and the asphalt layer of the base material, pinholes hardly occur and is excellent in durability.

As explained above, since the acrylic resin composition of the present invention contains the monomer (A), the monomer (B), the polymer (C) and the wax (D), not only the dry base material. In addition, a coating film excellent in adhesiveness can be formed on a wet substrate. In particular, even if the substrate has a complicated surface state or a substrate having cracks on the surface, the acrylic resin composition easily penetrates into the substrate, so that the adhesion between the substrate and the coating film is improved.
Conventional coating agents have insufficient adhesion to wet substrates. In particular, when heated after being applied to the base material, the coating film softens, so that there is a problem that the anchor effect on the base material is lowered and adhesiveness is lowered.
According to the acrylic resin composition of the present invention, even when the substrate is in a wet state, it has excellent adhesion to the substrate and is excellent in durability.
For this reason, the acrylic resin composition of the present invention does not need to dry a wet substrate before coating, and can simplify the number of work steps.
In addition, since the acrylic resin composition of the present invention has a high flash point, it is easy to handle.

  The acrylic resin composition of the present invention is suitable as a coating agent for floor surfaces such as concrete and asphalt, wall surfaces, and road pavement surfaces.

EXAMPLES Hereinafter, although an Example is shown and demonstrated about this invention, this invention is not limited to an Example.
In the following description, unless otherwise specified, “part” represents mass part, and “%” other than the degree of saponification and humidity represents “mass%”.

(Synthesis Example 1: Preparation of Composition S-1 Containing Polymer (C) Having Polymerizable Double Bond)
In a polymerization apparatus equipped with a stirrer, a cooling tube, and a thermometer, 135 parts of deionized water and 0.4 part of polyvinyl alcohol (saponification degree 80%, polymerization degree 1,700) as a dispersing agent are charged and stirred. Then, polyvinyl alcohol was dissolved. Stirring was stopped, 4 parts of methacrylic acid (hereinafter abbreviated as “MAA”), 96 parts of methyl methacrylate (hereinafter abbreviated as “MMA”), 2,2′-azobis-2-methylbutyroyl as a polymerization initiator. Nitrile (hereinafter abbreviated as “AMBN”) 0.2 part, n-dodecyl mercaptan (hereinafter abbreviated as “n-DM”) 0.8 part as a chain transfer agent, and sodium carbonate 0.1 part as an electrolyte. Added and stirred again. The temperature was raised to 75 ° C. and reacted for 2.5 hours, and then the temperature was raised to 98 ° C. and held for 1.5 hours to complete the first stage reaction. After cooling to 40 ° C., the obtained aqueous suspension was filtered through a polyamide filter cloth having an opening of 45 μm. The filtrate was washed with deionized water, dehydrated, and dried at 40 ° C. for 16 hours to obtain a granular vinyl polymer (first copolymer (C ′)). The granular vinyl polymer obtained had a Tg of 100 ° C. and a weight average molecular weight of 40,000. The Tg of the granular vinyl polymer was measured by DSC.

Next, 6.6 parts of glycidyl methacrylate (hereinafter abbreviated as “GMA”), 1.5 parts of tetrabutylammonium bromide as an esterification catalyst, polymerization inhibitor in a polymerization apparatus equipped with a stirrer, a condenser, and a thermometer 2,6-di-t-butyl-4-methylphenol (hereinafter abbreviated as “BHT”) 0.1 part, tetrahydrofurfuryl methacrylate (hereinafter abbreviated as “THFMA”) 108.16 parts and MMA54 Department was put in. While stirring these, 100 parts of the above granular vinyl polymer (first copolymer (C ′)) was gradually added, and after the entire amount was added, the temperature was raised to 90 ° C. and held for 2 hours. A step S reaction is performed, and a composition S-1 (hereinafter abbreviated as “S-1”) containing a polymer (C) having a polymerizable double bond having an acid value of 0.3 mgKOH / g, THFMA and MMA. Got. The amount of GMA used in the second stage reaction was 1.0 mole relative to 1 mole of MAA used in the first stage reaction.
The composition of the obtained S-1 and polymer (C) was as follows.
S-1: Polymer (C) /THFMA/MMA=106.6/108.16/54 (parts) = 40/40/20 (%).
Polymer (C) = MMA / MAA / GMA = 96/4 / 6.6 (parts) = 90 / 3.8 / 6.2 (%).

(Synthesis example 2: Preparation of composition S-2 containing a polymer having a polymerizable double bond)
Synthesis Example 1 except that the amount of MMA added was changed from 96 parts to 60 parts and 36 parts of n-butyl methacrylate (hereinafter abbreviated as “n-BMA”) was added in the first stage reaction of Synthesis Example 1. In the same manner as in Example 1, a granular vinyl polymer (first copolymer (C ′)) having a Tg of 71 ° C. and a weight average molecular weight of 40,000 was obtained.
Using the obtained granular vinyl polymer, a second-stage reaction was performed, and composition S-2 (hereinafter referred to as "THMA and MMA") containing a polymer having a polymerizable double bond having an acid value of 0.3 mgKOH / g. , "S-2").
The composition of the obtained S-2 and polymer was as follows.
S-2: Polymer / THFMA / MMA = 106.6 / 108.16 / 54 (parts) = 40/40/20 (%).
Polymer = MMA / n-BMA / MAA / GMA = 60/36/4 / 6.6 (part) = 56/34 / 3.8 / 6.2 (%).

(Synthesis Example 3: Preparation of composition S-3 containing polymer (C) having a polymerizable double bond)
In the same manner as in Synthesis Example 1, a granular vinyl polymer (first copolymer (C ′)) having a Tg of 100 ° C. and a weight average molecular weight of 40,000 was obtained.
When performing the second stage reaction using the obtained granular vinyl polymer, the amount of MMA added was changed from 54 parts to 0 parts, and the amount of THFMA used was changed to 162.16 parts. In the same manner as in Synthesis Example 1, the second stage reaction was performed, and a composition S-3 (hereinafter referred to as “S-”) containing a polymer (C) having a polymerizable double bond having an acid value of 0.3 mgKOH / g and THFMA. 3 ”).
The compositions of S-3 and polymer (C) obtained were as follows.
S-3: Polymer (C) /THFMA=106.6/162.16 (parts) = 40/60 (%).
Polymer (C) = MMA / MAA / GMA = 96/4 / 6.6 (parts) = 90 / 3.8 / 6.2 (%).

(Synthesis example 4: Preparation of composition S-4 containing polymer (C) having a polymerizable double bond)
In the same manner as in Synthesis Example 1, a granular vinyl polymer (first copolymer (C ′)) having a Tg of 100 ° C. and a weight average molecular weight of 40,000 was obtained.
When performing the second stage reaction using the obtained granular vinyl polymer, the amount of MMA added was changed from 54 parts to 162.16 parts, and the amount of THFMA used was changed to 0 parts. In the same manner as in Synthesis Example 1, the second stage reaction was carried out, and a composition S-4 (hereinafter referred to as “S-”) containing a polymer (C) having a polymerizable double bond having an acid value of 0.3 mgKOH / g and MMA. 4 ”).
The compositions of S-4 and polymer (C) obtained were as follows.
S-3: Polymer (C) /MMA=106.6/162.16 (parts) = 40/60 (%).
Polymer (C) = MMA / MAA / GMA = 96/4 / 6.6 (parts) = 90 / 3.8 / 6.2 (%).

(Synthesis Example 5: Synthesis of Composition P-1)
A granular vinyl polymer (first copolymer (C ′)) having a Tg of 100 ° C. and a weight average molecular weight of 40,000 obtained in the first stage reaction of Synthesis Example 1 was prepared as composition P-1 (hereinafter referred to as “ It was abbreviated as “P-1”.).
The composition of P-1 obtained was as follows.
P-1: First copolymer (C ′) = 100 (parts).
First copolymer (C ′) = MMA / MAA = 96/4 (parts) = 96/4 (%).

(Examples 1-13, Comparative Examples 1-8)
According to the composition of Tables 1 to 3, in a 1 L flask equipped with a stirrer, thermometer, and cooling tube, composition S-1 to S-4 or composition P-1, monomer (A), monomer (B) , Wax (D), decomposition accelerator (F), antifoaming agent (Disparon 230 (trade name, manufactured by Enomoto Kasei Co., Ltd.)), polymerization inhibitor (BHT), ultraviolet absorber (JF-77 (trade name, Johoku Chemical) Kogyo Co., Ltd.) and thixotropic agent (BYK-410 (trade name, manufactured by Big Chemie Japan)). Then, it heated at 70 degreeC for 2 hours, cooled to room temperature, and obtained the acrylic resin composition of the resin composition shown to Tables 4-6.
In addition, the component which does not have description of the compounding quantity in a table | surface shall not be mix | blended.
The obtained acrylic resin composition (hereinafter sometimes referred to as “composition I for measurement”) was evaluated for viscosity, contact angle, and flash point, and the results are shown in Tables 4-6.
1 part of cobalt naphthenate 6% solution (trade name: naphthex cobalt 6% (T), cobalt content 6%, manufactured by Nippon Kagaku Sangyo Co., Ltd.) as a decomposition accelerator for 100 parts of measurement composition I , NIPPER NS (trade name, manufactured by NOF Corporation, 40% product of dibenzoyl peroxide) which is an organic peroxide (E), curing rate modifier XD-7021 (trade name: Acrysilup XD-7021, Ryo 3 parts) were added and mixed to obtain an acrylic resin composition containing an organic peroxide (hereinafter sometimes referred to as composition II for measurement). The obtained measurement composition II was evaluated for curing time, coating workability, and wet coating workability. In addition, the cured measurement composition II was evaluated for Tg, wet heat durability, and hot / cold repeat test, and the results are shown in Tables 4-6.

Abbreviations in the table are as follows.
THFMA: Tetrahydrofurfuryl methacrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: acrylate ester THF).
2-HEMA: 2-hydroxyethyl methacrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: acrylate ester HO).
4-HBA: 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Co., Ltd., trade name: 4-HBA).
MMA: Methyl methacrylate (Mitsubishi Rayon Co., Ltd., trade name: Acryester M),
KBM-503: γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-503).
FA-512M: dicyclopentenyloxyethyl methacrylate (manufactured by Hitachi Chemical Co., Ltd., trade name FANCL FA-512M).
CHMA: cyclohexyl methacrylate (Made by Mitsubishi Rayon Co., Ltd., trade name: acrylate ester CH).
SLMA: alkyl methacrylate having 12 to 13 carbon atoms in the alkyl group (Mitsubishi Rayon Co., Ltd., trade name: Acryester SL).
BPE-4: Bisphenol type diacrylate (Daiichi Kogyo Seiyaku Co., Ltd., trade name: New Frontier BPE4).
EDMA: ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: acrylate ester ED).
P-115: Paraffin wax (manufactured by Nippon Seiwa).
-P-130: Paraffin wax (manufactured by Nippon Seiwa).
-P-150: Paraffin wax (manufactured by Nippon Seiwa).
DMPT: N, N-dimethyl-p-toluidine.
PTEO: N, N-di (2-hydroxyethyl) -p-toluidine.
Polymerization inhibitor: BHT (2,6-di-t-butyl 4-methylphenol).
Antifoaming agent: Disparon 230 (trade name, manufactured by Enomoto Kasei Co., Ltd.)
Thixotropic agent: BYK-410 (trade name, manufactured by Big Chemie Japan).
UV absorber: JF-77 (trade name, manufactured by Johoku Chemical Industry Co., Ltd.).

(Evaluation method)
<Viscosity>
Using a B-type viscometer (BM type, manufactured by Tokimec Co., Ltd.), the viscosity of composition for measurement I at 23 ° C. (viscosity at 60 rpm) was measured.

<Contact angle>
The composition for measurement I was allowed to stand for 4 hours in an environment variable chamber (3 m × 7 m × 3 m height) having a temperature of 23 ° C. and a relative humidity of 50% to acclimatize to the temperature of the environment variable chamber. An automatic contact angle meter manufactured by Kyowa Interface Science Co., Ltd. in the environment variable chamber using this measurement composition I and the glass plate (float plate glass described in JIS-R3202: 2011 “Float plate glass and polished plate glass”). The contact angle between the glass plate and the composition for measurement I was measured using DM-500. The measurement of the contact angle was evaluated by the “liquid suitable method”.
The obtained contact angles were classified according to the following evaluation criteria.

≪Evaluation criteria≫
A: Contact angle of less than 20 degrees.
○: Contact angle of 20 degrees or more and less than 35 degrees.
X: A contact angle of 35 degrees or more.

<Tg>
The composition for measurement II was polymerized and cured at an ambient temperature of 23 ° C. to prepare a cast plate having a thickness of 1 mm. This was measured by measuring the viscoelasticity of the cast plate (JIS-K7244-2: 1998, “Plastics—Test method for dynamic mechanical properties—Part 2: A method described in torsion pendulum method”).

<Flash point>
The flash point of the composition I for measurement was measured according to JIS K2265-2: 2007 “How to determine flash point—Part 2: Rapid equilibrium sealing method”.

<Curing time>
The composition II for measurement immediately after the addition of the organic peroxide (E) was placed in a test tube having a diameter of 10 mm and a length of 120 mm up to a height of 70 mm from the bottom.
A thermocouple was placed in the center of the measurement composition II in the depth direction. While the test tube was left in 23 ° C. water to cure the measurement composition I, the heat generation temperature was measured over time with the thermocouple. The time from the addition of the organic peroxide (E) to the time when the maximum exothermic temperature was reached was determined, and this time was taken as the curing time.

<Coating workability>
Workability, surface curability and adhesion when the measurement composition II of each example is applied to the surface of a concrete plate (30 cm × 30 cm × 6 cm) as a base material so as to be 0.4 kg / m ² . Was evaluated based on the following evaluation criteria. In addition, an evaluation result is an average of the result of having tested about five base materials.

<< Evaluation criteria for workability >>
Good (◯): The composition could be sufficiently leveled with a brush and applied uniformly.
Poor (x): When leveling the formulation with a brush, it took a very long time to obtain a highly viscous and / or uniform surface.

≪Surface Curability Evaluation Criteria≫
The curability of the surface of the obtained coating film was confirmed by finger touch and evaluated based on the following evaluation criteria.
○: Elapsed time less than 1 hour and no tack.
(Triangle | delta): There is no tack in elapsed time 1-2 hours.
X: Tack is present even after 2 hours.

<< Evaluation criteria for adhesiveness >>
About 5 base materials evaluated in <Coating workability> 24 hours after coating and curing the composition II for measurement, the coating strength test method (NNK- 005: 2006). In addition, when the area | region where evaluation differs was mixed, the area ratio of the area | region was written together. For example, “80% KH, 20SH” means that as an evaluation result of five substrates, the KH region was 80% and the SH region was 20%.
KH (good): substrate cohesive failure.
SH (defect): delamination between the base material and the undercoat layer.
JH (Poor): Cohesive failure of the undercoat layer.

<Wet coating workability>
In advance, a concrete plate (30 cm × 30 cm × thickness 6 cm) serving as a base material was immersed in water for 48 hours or more. The concrete board was taken out of the water, and the surface of the concrete board was immediately wiped with a waste cloth. The moisture content of the concrete board was measured with a moisture meter (trade name: HI-500, manufactured by Kett), and it was confirmed that the moisture content was 6% or more.
Immediately after confirming the moisture content, workability, surface curability and adhesiveness were evaluated in the same manner as in the above <Coating workability>.

<Hot and cold repeat test>
The hot and cold repeated test was evaluated according to JIS-A6909 finish coating material for construction.
However, what was laminated as follows was used as a sample.
On the surface of a mortar plate (7 cm × 7 cm × 2 cm thickness: JIS-A6909 7.2 base material for finishing coating material for construction), the measurement composition II in each example was 0.4 kg / m ^2. The undercoat layer was formed by coating with a brush.
Add 100 parts of Acrisilap XD-3026 (trade name, manufactured by Ryojo Co., Ltd.), an intermediate coating resin, and add 5 parts of Acrisilap MRT-40 (trade name, manufactured by Ryojo Co., Ltd.) as a colorant and stir. , Mixed. Next, to 100 parts of acrylic syrup XD-3026, 2 parts of a benzoyl peroxide 50% granule product (manufactured by Kayaku Akzo, trade name: Perkadox CH-50L) is added as a polymerization initiator, and further stirred and mixed. did. To this, 400 parts of aggregate (trade name: KM-17A, manufactured by Ryohin Co., Ltd.) was added and stirred to prepare an intermediate coating agent. Immediately after the preparation, the intermediate coat was applied to the surface of the undercoat layer so as to be 10 kg / m ² to form an intermediate coat layer.
As an overcoat layer, 10 parts of Acrysilap MRT-40 was added to 100 parts of Acrisilup XD-511 (trade name, manufactured by Ryohin Co., Ltd.), which is a resin for overcoating, and the mixture was stirred and mixed. To 100 parts of Acrysilap XD-511, 3 parts of Parkadox CH-50L was added, stirred and mixed to prepare a top coat. Immediately after the preparation, the top coat was applied with a brush so as to be 0.3 kg / m ² . Before the top coating was cured, No. 5 silica sand was uniformly spread on the surface of the top coating so as to be 0.5 kg / m ² . Next, the top coat was applied with a brush so as to be 0.4 kg / m ² to form a top coat layer. A bond quick mender (epoxy resin, manufactured by Konishi Co., Ltd.) was applied to four side surfaces so as to be 2.0 kg / m ² .
Thus, a coating comprising a coating in which an undercoat layer, an intermediate coat layer, and an overcoat layer were laminated in this order on the surface of the substrate was obtained.

  The three coatings were immersed in 23 ± 2 ° C. water for 18 hours, immediately cooled in a −20 ± 2 ° C. incubator for 3 hours, and then heated in another 50 ± 3 ° C. incubator for 3 hours. Warm up. The operation of setting this 24 hours as one cycle was repeated 10 times, and then allowed to stand in a test room (23 ° C.) for 24 hours. Then, the presence or absence of cracks, peeling and swelling of the coating was visually examined and evaluated according to the following evaluation criteria.

≪Evaluation criteria≫
Good (O): The coating film is not cracked, peeled or swollen.
Defect (x): Cracks, peeling and swelling are seen in the coating film.

<Damp heat durability>
The measurement composition II of each example was applied to the surface of a concrete plate (30 cm × 30 cm × 6 cm) so as to be 0.4 kg / m ² to obtain a coating. About this coating | coated, the swelling resistance was evaluated in accordance with the load test method as described in JHS-433-2 "swelling load method", and the result was made into wet heat durability.
The load test method was performed according to the following procedure.
After the measurement composition was cured, it was cured at room temperature for 24 hours to obtain a coating. The coating was immersed in 23 ± 2 ° C. water for 24 hours. The coating was taken out of the water, and allowed to stand for 24 hours in a constant temperature and humidity chamber having a temperature of 60 ± 2 ° C. and a humidity of 80 ± 5%, and then the coating film was visually observed. The observation results were evaluated according to the following evaluation criteria. If the coating is hard and brittle, dandruff is likely to occur.

≪Evaluation criteria≫
Good (O): No swelling occurs in the coating film.
Defect (x): A swelling occurred in the coating film.

As shown in Tables 4 to 6, in Examples 1 to 13 to which the present invention was applied, the curing time was in a range suitable for the painting work, and the coating workability, the wet coating workability, the hot and cold repeated test, and the wet heat durability. The property was good.
On the other hand, Comparative Example 1 containing no wax (D) did not cure. For this reason, about the comparative example 1, evaluation was not carried out about adhesiveness, a heat / cool repetition test, and heat durability.
Comparative Example 2 in which the methyl methacrylate unit in the polymer (C) is less than 75% by mass, a composition P-1 composed of a polymer containing no polymerizable double bond instead of the polymer (C) Example 3, Comparative Example 4 lacking monomer (a3), Comparative Example 7 lacking monomer (B), and Polymer lacking monomer (a2) and containing a polymerizable double bond (C In Comparative Example 8 having a large blending amount of), the wet heat durability was “x”.
In Comparative Example 5 lacking the monomer (a2), the adhesiveness in wet coating workability was “SH”, and in Comparative Example 6 lacking the monomer (a1), the flash point was 13 ° C. It was.
From these results, it was found that by applying the present invention, it is possible to form a coating film having excellent adhesion and excellent durability even on a wet substrate.

Claims (2)

A monomer (A) having one (meth) acryloyl group in the molecule, a monomer (B) having two or more (meth) acryloyl groups in the molecule, and a polymerizable double bond And a polymer (C) having 75% by mass or more of methyl methacrylate units, and a wax (D),
As the monomer (A), a (meth) acrylate (a1) having a heterocycle selected from the group consisting of a furan ring, a hydrofuran ring, a pyran ring and a hydropyran ring, a hydroxyalkyl (meth) acrylate (a2), An acrylic resin composition for coating a wet substrate, comprising methyl methacrylate (a3). 1-15 mass% of said polymers (C) are contained with respect to a total of 100 mass% of said monomer (A), said monomer (B), and said polymer (C). The acrylic resin composition for wet substrate coating according to claim 1.