JP6565590B2 - Curable composition and coated article - Google Patents

Description

  The present invention relates to a curable composition and a coated article.

Conventionally, as paints for vehicles and the like that require excellent coating performance such as high cosmetics and impact resistance, solvent-type or water-soluble acrylic resin / melamine resin paint, acrylic resin / urethane resin, etc. Many paints are used. However, the scratch resistance of coating films obtained from these paints was insufficient.
Patent Documents 1 and 2 contain a polyfunctional (meth) acrylate, a polyhydric alcohol mono (meth) acrylate polymer, a polyisocyanate, and a photopolymerization initiator, and can be cured by ultraviolet rays and heat to form a coating film. A composition is described. The coating film formed from these coating compositions has good cosmetic properties, adhesion, etc., but has insufficient alkali resistance.
Patent Document 3 describes a thermosetting coating composition containing a hydroxyl group-containing acrylic resin, a polyester resin, a bright pigment and a curing agent. Although the coating film formed from this coating composition has good alkali resistance, the scratch resistance of the coating film was insufficient.

JP-A-63-113085 JP 2003-277684 A JP 2013-139508 A

  The present invention relates to a curable composition that can be cured by heat and active energy rays to form a coating film having good cosmetic properties, scratch resistance, impact resistance, and alkali resistance, as well as cosmetic properties, scratch resistance, and impact resistance. It aims at providing the coated article which has a coating film with favorable property and alkali resistance.

  The present inventors have found that the above-mentioned problems can be solved by a curable composition containing a specific amount of a specific component and capable of being cured by heat and active energy rays to form a coating film, and have reached the present invention. That is, this invention has the following aspects.

[1] (A) a polyfunctional (meth) acrylate having three or more (meth) acryloyl groups, a structural unit (b1) derived from a (meth) acrylic acid adduct of (B) a saturated fatty acid glycidyl ester, and a hydroxyl group A copolymer containing the structural unit (b2) derived from (meth) acrylate (excluding the (meth) acrylic acid adduct of saturated fatty acid glycidyl ester), (C) polyisocyanate, and (D) photopolymerization initiation. And a curing agent containing 20 to 30% by mass of the component (A) and 70 to 80% by mass of the component (B) based on the total amount of the component (A) and the component (B). Sex composition.
[2] The curable composition according to [1], wherein the component (B) has a glass transition temperature of 40 to 90 ° C. and a weight average molecular weight of 2000 to 7000.
[3] The curable composition according to [1] or [2], wherein the content of the structural unit (b1) in the component (B) is 10 to 30% by mass with respect to the total of all the structural units. .
[4] A coated article having a coating film made of a cured product of the curable composition according to any one of [1] to [3] on at least a part of the surface of the substrate.

  According to the present invention, a curable composition that can be cured by heat and active energy rays to form a coating film having good cosmetic properties, scratch resistance, impact resistance, and alkali resistance, as well as cosmetic properties, scratch resistance, A coated article having a coating film with good impact resistance and alkali resistance can be provided.

≪Curable composition≫
The curable composition of the present invention (hereinafter also referred to as the present composition) contains the following components (A), (B), (C), and (D).
This composition may further contain other components other than (A) component, (B) component, (C) component, and (D) component as needed.
The present composition may further contain a solvent, if necessary.

<(A) component>
The component (A) is a polyfunctional (meth) acrylate having 3 or more (meth) acryloyl groups. The component (A) is a component that exhibits good polymerization activity and imparts scratch resistance to the coating film.
In the present specification and claims, “(meth) acryloyl” means “acryloyl” and “methacryloyl”, “(meth) acrylate” means “acrylate” and “methacrylate”, and “( “Meth) acrylic acid” means “acrylic acid” and “methacrylic acid”.

Examples of the component (A) include tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, and caprolactone-modified trimethylolpropane. Trifunctional (meth) acrylates such as tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate;
Pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, tripentaerythritol tetra (meth) acrylate, ethylene oxide modified pentaerythritol tetra (meth) acrylate, ethylene oxide modified dipentaerythritol tetra (meth) acrylate, ethylene 4 having a pentaerythritol skeleton such as oxide-modified tripentaerythritol tetra (meth) acrylate, caprolactone-modified pentaerythritol tetra (meth) acrylate, caprolactone-modified dipentaerythritol tetra (meth) acrylate, and caprolactone-modified tripentaerythritol tetra (meth) acrylate. Functional (meth) acrylate;
Dipentaerythritol penta (meth) acrylate, tripentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified tripentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol penta (meta) ) Pentafunctional (meth) acrylate having a pentaerythritol skeleton such as acrylate, caprolactone-modified tripentaerythritol penta (meth) acrylate;
Dipentaerythritol hexa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified tripentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meta) ) A hexafunctional (meth) acrylate having a pentaerythritol skeleton such as acrylate, caprolactone-modified tripentaerythritol hexa (meth) acrylate;
7-functional (meth) acrylates having a pentaerythritol skeleton such as tripentaerythritol hepta (meth) acrylate, ethylene oxide modified tripentaerythritol hepta (meth) acrylate, caprolactone modified tripentaerythritol hepta (meth) acrylate;
8-functional (meth) acrylate having a pentaerythritol skeleton such as tripentaerythritol octa (meth) acrylate, ethylene oxide-modified tripentaerythritol octa (meth) acrylate, caprolactone-modified tripentaerythritol octa (meth) acrylate;
A trifunctional urethane tri (meth) acrylate obtained by reacting a polyisocyanate having an isocyanurate skeleton with hydroxymono (meth) acrylate;
4-functional or higher functional urethane poly (meth) acrylate having a pentaerythritol skeleton such as urethane hexa (meth) acrylate obtained by reacting isophorone diisocyanate with pentaerythritol tri (meth) acrylate;
A tetra- or higher functional (meth) acrylate having a trimethylolpropane skeleton such as ditrimethylolpropane tetraacrylate;
And polyester poly (meth) acrylates such as polyester poly (meth) acrylate obtained by reacting trimethylolethane, succinic acid and (meth) acrylic acid.
Among these, from the viewpoint of curability, scratch resistance, and cost, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, hexafunctional The above urethane (meth) acrylate is preferable.
(A) A component may be used individually by 1 type and may be used in combination of 2 or more type.

<(B) component>
The component (B) is a copolymer containing the following structural unit (b1) and structural unit (b2). The component (B) may further include a structural unit other than the structural unit (b1) and the structural unit (b2).

  The structural unit (b1) is a structural unit derived from a (meth) acrylic acid adduct of saturated fatty acid glycidyl ester. The structural unit (b1) can impart hydrophobicity to the component (B) and improve the alkali resistance of the coating film.

Although it does not specifically limit as (meth) acrylic acid adduct of saturated fatty acid glycidyl ester, From the viewpoint of providing hydrophobicity to (B) component, that whose carbon number of a saturated fatty acid residue is 10 or more is preferable. The saturated fatty acid residue is a group (acyl group) obtained by removing OH from a carboxy group of a saturated fatty acid.
As the (meth) acrylic acid adduct of saturated fatty acid glycidyl ester, a (meth) acrylic acid adduct of neodecanoic acid glycidyl ester is particularly preferred because of the availability of saturated fatty acid glycidyl ester.

  The content of the structural unit (b1) in the component (B) is preferably 10 to 30% by mass with respect to the total of all the structural units because alkali resistance and compatibility with other components are improved. -20 mass% is more preferable.

The structural unit (b2) is a structural unit derived from a hydroxyl group-containing (meth) acrylate (excluding a (meth) acrylic acid adduct of a saturated fatty acid glycidyl ester).
Examples of the hydroxyl group-containing (meth) acrylate (excluding the (meth) acrylic acid adduct of saturated fatty acid glycidyl ester) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3- Hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, glycerin mono (meth) acrylate, polycaprolactone Modified hydroxylalkyl (meth) acrylate, polycaprolactone-modified poly (oxyalkylene) (meth) acrylate and the like can be mentioned. A hydroxyl-containing (meth) acrylate may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the structural unit (b2) in the component (B) is preferably 10 to 60% by mass and more preferably 20 to 60% by mass with respect to the total of all the structural units because scratch resistance becomes better. preferable.

Examples of the structural unit other than the structural unit (b1) and the structural unit (b2) include, for example, other vinyl monomers other than (meth) acrylic acid adducts of saturated fatty acid glycidyl esters and hydroxyl group-containing (meth) acrylates. The structural unit derived from is mentioned.
Other vinyl monomers may be those that can be copolymerized with a hydroxyl group-containing (meth) acrylate, such as (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, butyl ( Alkyl) (meth) acrylates such as meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; dibasic acids such as itaconic acid, maleic acid, fumaric acid and esters thereof; styrene, Examples include substituted or unsubstituted styrene such as vinyl toluene, dimethyl styrene, and ethyl styrene; (meth) acrylonitrile, (meth) acrylamide, vinyl acetate, and vinyl chloride. Other vinyl monomers may be used alone or in combination of two or more.

  The content of the other structural unit in the component (B) is preferably 10 to 80% by mass and more preferably 20 to 70% by mass with respect to the total of all the structural units from the viewpoint of alkali resistance and scratch resistance.

(B) 40-90 degreeC is preferable and the glass transition temperature of a component has more preferable 40-70 degreeC. When the glass transition temperature is within the above range, the balance between the coating film hardness, the resin viscosity, and the coating film appearance becomes better.
The glass transition temperature of (B) component is calculated | required by the method shown in the Example mentioned later.

(B) As for the mass mean molecular weight of a component, 2000-7000 are preferable and 2000-5000 are more preferable. When the mass average molecular weight is within the above range, the scratch resistance and leveling properties of the coating film become better.
(B) The mass average molecular weight of a component is measured by the method shown in the Example mentioned later.

The hydroxyl value of the component (B) is preferably 60 to 180 mgKOH / g, more preferably 100 to 180 mgKOH / g. When the hydroxyl value is within the above range, the scratch resistance and impact resistance of the coating film become better.
The hydroxyl value of (B) component is measured by the method shown in the Example mentioned later.

Component (B) can be produced, for example, by the following method (1), (2) or (3).
(1) In the presence of a saturated fatty acid glycidyl ester, (meth) acrylic acid, a hydroxyl group-containing (meth) acrylate, and, if necessary, a monomer component containing other monomers are (co) polymerized and polymerized. A method of adding saturated fatty acid glycidyl ester to (meth) acrylic acid during the reaction.
(2) A (meth) acrylic acid adduct of a saturated fatty acid glycidyl ester obtained by reacting a saturated fatty acid glycidyl ester with (meth) acrylic acid, a hydroxyl group-containing (meth) acrylate, and other units as required. A method of (co) polymerizing monomer components including a monomer.
(3) To the carboxy group of the copolymer obtained by (co) polymerizing (meth) acrylic acid, a hydroxyl group-containing (meth) acrylate, and a monomer component containing another monomer as required. A method of reacting an epoxy group of a saturated fatty acid glycidyl ester.

The amount of (meth) acrylic acid used to obtain a (meth) acrylic acid adduct of a saturated fatty acid glycidyl ester or a structural unit derived therefrom is 0.8 to 1.2 mol relative to 1 mol of the fatty acid glycidyl ester. Is preferable, 0.9 to 1.1 mol is more preferable, and 1 mol (equal mol) is particularly preferable.
Among the above methods, the method (1) is preferable from the viewpoint of the number of production steps, and the polymerization temperature is preferably 140 ° C. or higher and 170 ° C. or lower.

In the polymerization for producing the component (B), a polymerization initiator may be used.
Examples of the polymerization initiator include organic peroxide polymerization initiators and azo polymerization initiators.
Although the usage-amount of a polymerization initiator does not have a restriction | limiting in particular, 0.5-15 mass parts is preferable with respect to 100 mass parts of total amounts of a monomer component.

<(C) component>
Component (C) is a polyisocyanate. The component (C) is used for the purpose of reacting with the component (B) by heat to crosslink the component (B).
As the component (C), an aliphatic or alicyclic polyisocyanate compound is preferably used. Typical examples include a reaction product of hexamethylene diisocyanate and / or isophorone diisocyanate and a polyhydric alcohol and / or a low molecular weight polyester polyol, an isocyanurate body which is a polymer of hexamethylene diisocyanate and / or isophorone diisocyanate, A let body etc. are mentioned. In addition, blocked isocyanates in which isocyanate groups in these polymers are masked with a compound having a hydroxyl group or the like are also preferably used. Various polyisocyanate compounds such as polymers of diisocyanate compounds other than those described above can also be used. (C) A component may be used individually by 1 type and may be used in combination of 2 or more type.

<(D) component>
The component (D) is a photopolymerization initiator. Since the component (D) generates radicals upon irradiation with active energy rays, the component (D) is blended for the purpose of reacting and crosslinking the component (A).
Specific examples of the component (D) include, for example, benzophenone, 4-methylbenzophenone, 2-methylbenzophenone, 4,4-bis (diethylamino) benzophenone, 2,4,6-trimethylbenzophene, 4-phenylbenzophenone, and the like. Benzophenone derivatives;
anthraquinone derivatives such as t-butylanthraquinone and 2-ethylanthraquinone;
2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl} Α-hydroxyacetophenones such as 2-methylpropan-1-one;
2-Benzyl-2-dimethylamino-4-morpholinobutyrophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-methyl-1- [4- (methylthio) phenyl] Α-aminoacetophenones such as 2-morpholinopropan-1-one and 2- (dimethylamino) -2- (4-methylbenzyl) -1- (4-morpholinophenyl) -butan-1-one;
2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, etc. Acylphosphine oxide derivatives;
Benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether;
Examples thereof include methyl orthobenzoyl benzoate, diethoxyacetophenone, benzyl dimethyl ketal, diethyl thioxanthone, isopropyl thioxanthone, and methyl benzoyl formate. (D) A component may be used individually by 1 type and may be used in combination of 2 or more type.
Among these, 1-hydroxycyclohexyl phenyl ketone is preferable from the viewpoint of cost.

<Other ingredients>
This composition can contain at least 1 sort (s) chosen from the group which consists of a ultraviolet absorber and a light stabilizer in order to improve the weather resistance of a coating film.
Although it will not specifically limit as a ultraviolet absorber if the weather resistance of a coating film can be improved, It melt | dissolves with respect to the (A) component and the organic solvent mix | blended as needed in this composition. Those are preferred. A compound derived from a triazine, benzophenone, benzotriazole, phenyl salicylate, phenyl benzoate having a maximum absorption wavelength from the viewpoint of high solubility in this composition and good weather resistance. Is preferably an ultraviolet absorber having a wavelength of 240 to 380 nm.

Specific examples of the light stabilizer include bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1-methyl-8-bis (1,2,2,6,6-pentamethyl-4 -Piperidyl) sebacate, (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), 2,4-bis [N-butyl- (1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl) Amino] -6- (2-hydroxyethylamine) -1,3,5-triazine, reaction product of sebacic acid and bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) ester Etc. That.
Among these, from the viewpoint of cost, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and 1-methyl-8-bis (1,2,2,6,6-pentamethyl-4- A mixture with piperidyl) sebacate is preferred. As this mixture, for example, commercially available Tinuvin (registered trademark) 292 (manufactured by BASF Japan) can be used.

  The present composition may contain a leveling agent for the purpose of preventing repellency and obtaining the smoothness of the coating film. Examples of the leveling agent include fluorine-based, silicon-based, and acrylic-based agents. Among these, an acrylic leveling agent is preferable in order to obtain recoatability.

  The present composition comprises an antifoaming agent, an anti-settling agent, a lubricant, an abrasive, an antirust agent, an antistatic agent, a sensitizer, a polymerization inhibitor, an antioxidant, a clouding agent, a dispersant, a thickener, Anti-sagging agent, desiccant, adhesion promoter, film modifier, slip agent, anti-scratch agent, plasticizer, matting agent, low shrinkage agent, antibacterial agent, antifungal agent, antifouling agent, flame retardant, curing Contains additives such as accelerators, deterioration inhibitors, photopolymerization accelerators, thermal initiators, polypropylene (PP) adhesion promoters (chlorinated PP), thixotropic agents, dyes, pigments, fine particles, reactive fine particles, and bactericides. May be.

<Solvent>
Specific examples of the solvent include alcohol solvents such as ethanol, isopropanol, and normal butanol; ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, and methoxyethyl acetate. Ether solvents such as diethyl ether, ethylene glycol dimethyl ether and dioxane; aromatic solvents such as toluene and xylene; aliphatic solvents such as pentane and hexane;

<Content of each component>
Content of (A) component in this composition is 20-30 mass% with respect to the total amount (100 mass%) of (A) component and (B) component from a viewpoint of abrasion resistance and impact resistance. From the viewpoint of further improving the balance between scratch resistance and impact resistance, 25 to 30% by mass is preferable.

  Content of (B) component in this composition is 70-80 mass% with respect to the total amount of (A) component and (B) component from a viewpoint of scratch resistance and impact resistance, 70 to 75% by mass is preferable because the balance of impact resistance is further improved.

  Content of (C) component in this composition is determined according to the mole number of the hydroxyl group of (B) component. From the viewpoint of the curability and scratch resistance of the coating film, an amount in which the isocyanate group of the component (C) is 0.5 to 1.5 equivalents relative to 1 equivalent of the hydroxyl group of the component (B) is preferable. An amount of -1.2 equivalent is more preferred.

  As for content of (D) component in this composition, 0.1-20 mass parts is preferable with respect to 100 mass parts of total amounts of (A) component. There exists a tendency for the sclerosis | hardenability of this composition and the hardness of a coating film to improve, so that there is much content of (D) component. However, since the component (D) is expensive, the smaller the component, the lower the production cost of the composition.

  When this composition contains an ultraviolet absorber, the content of the ultraviolet absorber in this composition is the component (A) from the viewpoints of curability and abrasion resistance and weather resistance (yellowing resistance) of the coating film. And 0.1-20 mass parts is preferable with respect to 100 mass parts of total amounts of (B) component, and 0.1-10 mass parts is more preferable.

  When this composition contains a light stabilizer, content of the light stabilizer in this composition is 100 from the viewpoint of the weather resistance (crack resistance) of a coating film, and the total amount of (A) component and (B) component is 100. 0.1-5 mass parts is preferable with respect to mass parts, and 0.1-2 mass parts is more preferable.

<Effect>
This composition contains the component (A), the component (B), the component (C), the component (D), and the contents of the component (A) and the component (B) are within a specific range. Further, the coating film formed by curing the composition can be cured with active energy rays, and has good cosmetic properties, scratch resistance, impact resistance and alkali resistance.
Therefore, a coated article having a coating film having good cosmetic properties, scratch resistance, impact resistance and alkali resistance can be obtained by applying the composition to a substrate and curing the composition.

≪Painted article≫
The coated article of the present invention (hereinafter also referred to as the present coated article) has a coating film made of a cured product of the present composition on at least a part of the surface of the substrate.

Although the film thickness of a coating film is not specifically limited, 10-60 micrometers is preferable.
The substrate is not particularly limited, and examples thereof include structures, wood products, metal products, plastic products, rubber products, processed paper, ceramic products, and glass products. More specifically, automobiles, automotive parts (for example, parts such as bodies, bumpers, spoilers, mirrors, wheels, interior materials, etc., of various materials), metal plates such as steel plates, motorcycle parts, motorcycle parts , Road materials (eg, guardrails, traffic signs, noise barriers, etc.), tunnel materials (eg, side walls, etc.), ships, railway vehicles, aircraft, furniture, musical instruments, household appliances, building materials, containers, office supplies, Examples include sports equipment and toys. Among these, vehicle applications such as automobiles, automobile parts, motorcycles, and motorcycle parts are suitable.

  Although the manufacturing method of this coated article is not specifically limited, For example, the manufacturing method including the following application | coating processes, a drying process, a heating process, and an active energy ray irradiation process is mentioned.

In the application step, the composition is applied to at least a part of the surface of the substrate.
Examples of the application method of the composition include brush coating, spray coating, dip coating, spin coating, and flow coating. In particular, the spray coating method is preferable from the viewpoint of coating workability, coating film smoothness, and uniformity.

In the drying process, the solvent is volatilized from the present composition applied in the application process, or the thermosetting component is partially reacted. Here, the reaction of the thermosetting component means reacting the component (B) with the component (C).
In the drying step, heating is usually performed using an infrared (IR) heater or a hot air dryer. The heating conditions are, for example, about 40 to 150 ° C. for about 1 to 10 minutes.

In the heating step, the thermosetting component that has not reacted in the drying step is reacted. The heating conditions are, for example, about 50 to 200 ° C. and about 1 to 10 minutes.
In the active energy ray irradiation step, radicals are generated from the component (D), and the component (A) and the like are polymerized and cured. As the active energy ray, ultraviolet rays are preferable. As the ultraviolet light source, a high-pressure mercury lamp, a metal halide lamp, or the like can be used. Irradiation conditions, 50~250mW / cm ² irradiation intensity at a wavelength 340~380nm is, integrated light quantity is suitable 100~4000mJ / cm ^2.

The order of the heating step and the active energy ray irradiation step is not particularly limited, and the active energy ray irradiation step may be performed after the heating step is performed, and the heating step is performed after the active energy ray irradiation step is performed. You may go.
In the above manufacturing method, one of the heating step and the active energy ray irradiation step may be omitted. In terms of the scratch resistance of the coating film, it is preferable to perform both the heating step and the active energy ray irradiation step.

<Effect>
The coating film comprising the cured product of the present composition possessed by the present coated article has good cosmetic properties, scratch resistance, impact resistance and alkali resistance.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples do not limit the scope of the present invention.
In the examples, “part” means “part by mass”. “%” Means “mass%” unless otherwise specified.
Moreover, the measuring method of the characteristic (glass transition temperature, mass average molecular weight, hydroxyl value) of a polymer, and the evaluation method of the obtained coating film are as follows.

(Glass-transition temperature)
The glass transition temperature was calculated by using the Fox equation (TG Fox, Bull. Am. Physics Soc., Vol. 1, No. 3, page 123 (1956)).
The glass transition temperature of a copolymer containing a plurality of different monomer units can be determined using the following calculation formula.
1 / Tg = Σ [w (Mi) / Tg (Mi)]
(In the formula, w (Mi) is a mass fraction of the monomer unit Mi constituting the copolymer, and Tg (Mi) is a glass transition temperature of the homopolymer of Mi).
In addition, the glass transition temperature of a homopolymer can be calculated | required using the value described in polymer handbook "Polymer HandBook, J. Brandrup, Interscience, 1998". When there is no description, it can calculate using measured values, such as a differential scanning calorimeter.
The Tg of the homopolymer of an acrylic acid adduct of glycidyl neodecanoate was calculated at -55 ° C.

(Mass average molecular weight)
The mass average molecular weight was measured by the following method.
After preparing a tetrahydrofuran solution (solid content 0.4%) of the polymer, 100 μL of the above solution was injected into a TOSO gel permeation chromatography apparatus equipped with a TOSO column (GE4000HXL and G2000HXL), and the flow rate was Gel permeation chromatography was performed under the conditions of 1 mL / min, eluent: tetrahydrofuran, column temperature: 40 ° C., and the mass average molecular weight in terms of standard polystyrene was determined.

(Hydroxyl value)
The hydroxyl value was determined using the following calculation formula.
Hydroxyl value (mgKOH / g) = 56100 (mgKOH / mol) × Σ [w (b2) / (100 × M _b2 )]
(In the formula, w (b2) is a mass fraction of the monomer (b2) constituting the copolymer, and _Mb2 is a hydroxyl equivalent (g / mol) of the monomer (b2)). . )
The monomer (b2) is a monomer corresponding to the structural unit (b2).
The hydroxyl value is a calculated value obtained from the amount of the monomer (b2) used in the production of the copolymer, and does not include the amount of hydroxyl group derived from the structural unit (b1).

(Appearance of coating film)
The 60 ° specular glossiness of the obtained coating film was measured using a variable angle gloss meter (VG-7000 manufactured by Nippon Denshoku Industries Co., Ltd.). From the measured 60 ° specular gloss, the appearance of the coating film was judged according to the following criteria.
“◯”: 95 or more.
"X": Less than 95.

(Abrasion resistance)
The pencil hardness of the obtained coating film was measured in accordance with JIS K5600-5-4: 1999 (General coating test method-Part 5: Mechanical properties of coating film-Section 4: Scratch hardness (pencil method)). From the measured pencil hardness, the scratch resistance of the coating film was determined according to the following criteria.
“◯”: F or more.
“×”: HB or less.

(Impact resistance)
The obtained coated article was placed on the support of a DuPont impact tester with the coating surface facing upward, and a striker with a hemispherical tip with a radius of 6.35 mm was placed on the coating surface. A 500 g weight was dropped from a height of 20 cm onto the strike core. Thereafter, the indented part of the coating film (the part where the tip of the hitting core hit) and the surrounding area were visually observed, and the impact resistance of the coating film was determined according to the following criteria.
“O”: There is no crack or peeling at the indentation and its surroundings.
“×”: cracks and peelings are seen in the indentation and its surroundings.

(Alkali resistance)
A polyethylene cylinder having an inner diameter of 25 mm and a height of 15 mm was placed on the coating film, and was firmly adhered to the coating film with a crimping device such as a rubber band. 2 mL of 1/10 mol / L sodium hydroxide aqueous solution was dropped into the opening, and a test was performed in a drier kept at 55 ° C. for 4 hours. After the test, the coating film was washed with water, the state of the coating film in contact with the sodium hydroxide aqueous solution was visually observed, and the alkali resistance of the coating film was determined according to the following criteria.
“◯”: There is no change in the coating film.
“×”: blistering is observed in the coating film.

<Production Example 1: Synthesis of polymer (PA-1)>
A four-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was charged with 32 parts of butyl acetate and 14 parts of neodecanoic acid glycidyl ester (Cardura E10P, manufactured by Momentive). The temperature was raised to 170 ° C. over time. After reaching 170 ° C., 46 parts of styrene, 8.5 parts of methyl methacrylate, 5 parts of acrylic acid, 26.5 parts of hydroxyethyl methacrylate, and perbutyl (registered trademark) D (polymerization initiator, manufactured by NOF Corporation) as an initial initiator ) A monomer mixture composed of 5.6 parts was dropped over 2 hours. Next, the temperature was lowered to 125 ° C. over 1 hour, and a mixture of 5 parts of butyl acetate and 0.3 part of perbutyl O (polymerization initiator, manufactured by NOF Corporation, trade name) was added dropwise over 30 minutes. After holding at 125 ° C. for 1 hour, the mixture was cooled and 5.7 parts of butyl acetate was added to obtain a polymer (PA-1). The obtained polymer (PA-1) had a solid content of 70%, a glass transition temperature of 46 ° C., a weight average molecular weight of 4500, and a hydroxyl value of 115 mgKOH / g.

<Production Example 2: Synthesis of polymer (PA-2)>
A composition comprising only 32 parts of butyl acetate without adding neodecanoic acid glycidyl ester to the initial charge, and after heating, 46 parts of styrene, 27.5 parts of methyl methacrylate, 26.5 parts of hydroxyethyl methacrylate, and 5.6 parts of perbutyl D The same procedure as in Production Example 1 was carried out except that the monomer mixture was added dropwise over 2 hours and the amount of butyl acetate added after the polymerization was completed and cooled was 19.4 parts. The union (PA-2) was obtained. The obtained polymer (PA-2) had a solid content of 65%, a glass transition temperature of 88 ° C., a mass average molecular weight of 3000, and a hydroxyl value of 115 mgKOH / g.

<Production Example 3: Synthesis of polymer (PA-3)>
The composition of the monomer mixture to be dropped after the temperature rise was changed to a composition comprising 46 parts of styrene, 8.5 parts of methyl methacrylate, 26.5 parts of hydroxyethyl methacrylate, 19 parts of acrylic acid, and 5.6 parts of perbutyl D. The same operation as in Production Example 2 was performed to obtain a polymer (PA-3). The obtained polymer (PA-3) had a solid content of 65%, a glass transition temperature of 88 ° C., a weight average molecular weight of 3900, and a hydroxyl value of 115 mgKOH / g.

<Example 1>
Each component shown in Table 1 (the numerical values in the table are parts by mass) was mixed and stirred for about 30 minutes until the whole became uniform to prepare a liquid heat and active energy ray-curable composition.
This curable composition was applied onto a laminate composed of zinc phosphate-treated steel sheet / melamine base / melamine top by air spray coating so that the film thickness after curing was 30 to 40 μm, and a dryer. At 80 ° C. for 3 minutes to evaporate the solvent and form a dry film. Next, the dried film was cured by irradiating with ultraviolet rays under the conditions of an irradiation intensity of 80 mW / cm ^{2 at} a wavelength of 340 to 380 nm and an integrated light amount of 1000 mJ / cm ² using a metal halide lamp in the air, and then dried. A coating film (cured film) was formed by heat curing at 120 ° C. for 5 minutes in the machine to obtain a coated article. The evaluation results are shown in Table 1.

<Examples 2-3 and Comparative Examples 1-4>
Except having set it as the compounding ratio shown to Tables 1-2, it carried out similarly to Example 1, and prepared the heat | fever and active energy ray curable composition, and produced the coated article. The evaluation results are shown in Tables 1-2.

In Tables 1-2, the compounding quantity of (B) component is the quantity also including a non-solid content. (A): (B) indicates a mass ratio of the (A) component and the (B) component in terms of solid content.
Abbreviations in Tables 1 and 2 represent the following compounds.
“DPHA”: a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (trade name: KAYARAD (registered trademark) DPHA, manufactured by Nippon Kayaku Co., Ltd.).
“THEICTA”: tris (2-hydroxyethyl) isocyanurate triacrylate (trade name: NK ester A-9300S, manufactured by Shin-Nakamura Chemical Co., Ltd.).
“PETA”: pentaerythritol tetraacrylate (trade name: NK Ester A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.).
“PU-610”: hexafunctional aliphatic urethane acrylate (trade name: MIRAMER (registered trademark) PU-610, manufactured by MIWON).
“N3300”: hexamethylene diisocyanate type isocyanurate (trade name: Sumidur (registered trademark) N3300, manufactured by Sumika Bayer Urethane Co., Ltd.).
“HCPK”: 1-hydroxycyclohexyl phenyl ketone (trade name: LUNACURE (registered trademark) 200, manufactured by DKSH Japan).
“Tinuvin 292”: bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and 1-methyl-8-bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (Trade name: Tinuvin 292, manufactured by BASF Japan Ltd.).
“TinuvinPS”: 2- (5-t-butyl-2-hydroxyphenyl) benzotriazole (trade name: TinuvinPS, manufactured by BASF Japan Ltd.).
“Modaflow Resin”: an acrylic leveling agent (trade name: Modaflow Resin, manufactured by CYTEC).
“PMA”: propylene glycol monomethyl ether acetate (trade name: PMA, manufactured by KH Neochem).
“BuAc”: butyl acetate (trade name: butyl acetate, manufactured by Daicel Corporation).
“Xy”: xylene (trade name: xylol, manufactured by Daishin Chemical Co., Ltd.).
“T-SOL-100”: an aromatic hydrocarbon solvent (trade name: T-SOL-100, manufactured by TonenGeneral Sekiyu KK).

As shown in the above results, the coating films formed from the curable compositions of Examples 1 to 3 had good appearance (decorative properties), scratch resistance, impact resistance, and alkali resistance.
On the other hand, the coating formed from the curable composition of Comparative Example 1 in which the component (A) is less than 20% by mass and the component (B) is more than 80% by mass relative to the total amount of the components (A) and (B). The film was inferior in scratch resistance and alkali resistance.
The coating film formed from the curable composition of Comparative Example 2 in which the component (A) is more than 30% by mass and the component (B) is less than 70% by mass with respect to the total amount of the component (A) and the component (B). The impact resistance was poor.
(B) The coating film formed from the curable composition of Comparative Examples 3-4 which does not have the structural unit derived from the (meth) acrylic acid adduct of saturated fatty acid glycidyl ester is inferior in an external appearance and alkali resistance. It was.

Claims (4)

(A) a polyfunctional (meth) acrylate having 3 or more (meth) acryloyl groups;
(B) the structural unit (b1) and the hydroxyl group-containing (meth) acrylate having a carbon number of the saturated fatty acid glycidyl ester is 10 or more (meth) acrylic acid adducts of saturated fatty acid residues (where the saturated fatty acid glycidyl ester ( Except for the (meth) acrylic acid adduct, and a copolymer comprising the structural unit (b2)
(C) a polyisocyanate;
(D) a photopolymerization initiator;
Containing
The curable composition whose said (A) component is 20-30 mass% and whose said (B) component is 70-80 mass% with respect to the total amount of the said (A) component and the said (B) component.   The curable composition according to claim 1, wherein the component (B) has a glass transition temperature of 40 to 90 ° C. and a weight average molecular weight of 2000 to 7000.   Content of the said structural unit (b1) in the said (B) component is 10-30 mass% with respect to the sum total of all the structural units, The curable composition of Claim 1 or 2.   The coated article which has a coating film which consists of hardened | cured material of the curable composition as described in any one of Claims 1-3 on the surface of at least one part of a base material.