JP5715799B2 - Active energy ray-curable composition and coating film obtained by curing the same - Google Patents

Description

  The present invention relates to an active energy ray-curable composition modified with polymer fine particles.

  Polymer fine particles having a particle size of about 1 to 50 μm are used as resin modifiers, paint fields, light diffusing agents or matting agents, slipperiness imparting agents in cosmetics, and toner materials in the field of electronic copying machines. Has been.

  Such a blend of polymer fine particles of about 1 to 50 μm and an acrylic monomer is used as an active energy ray-curable coating having light diffusibility. Patent Document 1 discloses a composition using acrylic particles and styrene particles having an average particle diameter of 1 to 30 μm as a light diffusing agent. Patent Document 2 discloses a composition using silicone polymer fine particles having an average particle diameter of 0.5 to 20 μm as a light diffusing agent. What is used here is in powder form.

In mixing such powdery particles with a liquid medium such as an acrylic monomer, it is difficult to transmit shearing force due to stirring or the like. Most primary particles remain aggregated and are present in the vinyl monomer without being dispersed. If used in such a state, problems such as poor appearance tend to occur.
Moreover, since these polymer fine particles are required to be easily handled as a powder, their composition is limited. For example, in a soft rubbery composition, heat fusion between particles tends to occur, so it does not become powdery, but it becomes a large lump, so it has a relatively hard composition for recovery as powder. There must be. On the other hand, when a hard composition is used, there is a risk of dust generation peculiar to the powder and a dust explosion associated therewith.

  By the way, in general, the physical properties and appearance of the formed coating film are important in the coating (coating), and the active energy ray-curable coating also has excellent elongation (toughness) as one of the physical properties. It is desired to obtain a coating film.

  Core shell type polymer fine particles are generally added to thermoplastic resins as impact resistance improvers, and impart high shear at the time of molding to improve their toughness by dispersing them in the form of primary particles in the thermoplastic resin. It is known that the effect is manifested effectively. In thermoplastic resins, it is easy to add and mix core-shell polymers under high shear, so that powder core-shell polymers can be dispersed in primary particles, and core-shell polymers have a high toughness-improving effect. It is well known that it is important that the core-shell polymer is dispersed in the primary particles. Patent Document 3 discloses a thermoplastic resin composition having improved toughness using a core-shell type polymer having a primary particle size of about 1 to 50 μm.

  Patent Documents 1 and 2 have no examples of using core-shell fine particles of about 1 to 50 μm, and no active energy ray-curable composition using such core-shell type fine particles has been known so far. It was.

JP 2009-114302 A JP 2010-39124 A International Patent Publication No. 2007-0669493

  As can be seen from such technical background, an active energy ray-curable coating composition containing core / shell polymer fine particles of about 1 to 50 μm as a constituent component for improving the (mechanical) physical properties of the coating film is conventionally assumed. I did not come.

  This is because even if an active energy ray-curable coating composition is prepared using powdered core-shell type polymer fine particles, it is difficult to disperse even to primary particles, so that it is more coated than particles having no core-shell structure. This is because there is a problem that it is difficult to obtain a sufficient effect of improving the (mechanical) physical properties of the film.

  In such a situation, by using the polymer fine particles of the present invention, as described above, an active energy ray-curable coating composition that has never been obtained can obtain a coating film having excellent characteristics without appearance problems. For the purpose of providing, the present invention has been made.

  As a result of intensive studies, surprisingly, the active energy ray-curable coating composition of the present invention comprising polymer fine particles and a vinyl monomer is excellent in appearance and (mechanical) properties of a coating film, which has been difficult in the prior art. It has been found that it is possible to provide a coating.

That is, the present invention is an active energy ray-curable coating composition comprising 100 parts by weight of a vinyl monomer (A) and 1 to 200 parts by weight of polymer fine particles (B) having a volume average particle diameter of 1 to 50 μm,
The vinyl monomer (A) relates to an active energy ray-curable coating composition whose main component is one or more monomers selected from the group consisting of (meth) acrylic acid ester monomers and urethane-modified (meth) acrylates. .

  In other words, the main component of the vinyl monomer (A) is preferably a (meth) acrylic acid ester monomer or a urethane-modified (meth) acrylate, and these may be used in combination.

  In a preferred embodiment, the polymer fine particle (B) is a core / shell graft copolymer comprising at least two layers of an elastic core layer existing inside thereof and a shell layer existing outside thereof, and The elastic core layer is made of polymer fine particles (B) made of a rubber-like polymer having a glass transition temperature of less than 0 ° C.

  A preferred embodiment is an active energy ray-curable coating composition containing a polymer fine particle-containing vinyl monomer composition, wherein the polymer fine particles (B) are primarily dispersed in the vinyl monomer (A). It is. Thus, since the core-shell type polymer fine particles are stably dispersed in the state of primary particles in the vinyl monomer (A), the original mechanical strength improving effect of the core-shell type polymer can be exhibited, and the cured product is Excellent mechanical properties, optical properties and appearance. In addition, by using such a polymer fine particle-containing vinyl monomer composition as a raw material, the effect of eliminating the need for imparting high shear in order to disperse the core-shell type polymer fine particles as primary particles in the composition of the present invention. In addition, there is an effect that a coating film having an excellent appearance can be obtained.

  Moreover, this invention relates to the coating film formed by hardening | curing such an active energy ray-curable coating composition of this invention.

  The active energy ray-curable coating composition of the present invention, which has been difficult in the prior art, is a coating comprising polymer fine particles, particularly core-shell type polymer fine particles, and having excellent appearance and coating (mechanical and optical) properties. It is possible to provide a membrane.

  Hereinafter, embodiments of the present invention will be described.

<Active energy ray-curable coating composition>
The active energy ray-curable coating composition of the present invention comprises 100 parts by weight of a vinyl monomer (A) and 1 to 200 parts by weight of polymer fine particles (B) having a volume average particle diameter of 1 to 50 μm. From the viewpoint of a coating composition excellent in appearance and mechanical strength,
The vinyl monomer (A) is required to contain as a main component at least one monomer selected from the group consisting of (meth) acrylic acid ester monomers and urethane-modified (meth) acrylates.

  The active energy ray-curable coating composition of the present invention needs to contain 1 to 200 parts by weight of the polymer fine particles (B) with respect to 100 parts by weight of the vinyl monomer (A) as described above. When the content of (B) is less than 1 part by weight, the effect of the present invention is not observed, and when it exceeds 200 parts by weight, handling may be hindered. Preferably, the content of the polymer fine particles (B) is 5 to 100 parts by weight.

  In the present invention, the primary particle size of the polymer fine particles (B) has a volume average particle size of 1 to 50 μm, preferably 1 to 20 μm. Furthermore, the composition of the present invention comprises polymer fine particle-containing vinyl monomer composition in which polymer fine particles (B) are dispersed in primary particles in a continuous layer of vinyl monomer (A), and other compositions of the present invention. It is preferable that it is produced by mixing. That is, (B) is dispersed in (A) with a particle size of 1 to 50 μm, and by mixing such a composition with the other composition of the present invention, the composition of the present invention, Even in the cured product, the polymer fine particles (B) are dispersed in the form of primary particles. By including the polymer fine particles (B) dispersed in the state of such primary particles, the composition of the present invention has a further excellent quality in which the effect of improving the mechanical strength of each primary particle is sufficiently exhibited. Thus, a more preferable active energy ray-curable coating composition modified with polymer fine particles is obtained. That is, in the prior art, it was extremely difficult to actually mix polymer fine particles into a vinyl monomer and stably disperse them with primary particles. The product is represented by improved elongation, preferably using a polymer fine particle-containing vinyl monomer composition in which polymer fine particles (B) are dispersed as primary particles in a continuous layer of vinyl monomer (A). It becomes a more preferable active energy ray-curable coating composition.

  Further, the polymer fine particles (B) are not dissolved even if they swell in the vinyl monomer (A) component. Furthermore, the polymer fine particle (B) may be a polymer having a cross-linked structure so that the fine polymer particle (B) does not lose the form of the fine particle even if it swells even in the solvent that is a good solvent. preferable. The polymer fine particles (B) are dispersed in the state of primary particles in the continuous layer of the vinyl monomer (A) (hereinafter also referred to as primary dispersion) by measuring the dispersed particle diameter. For example, it can be confirmed by measuring the particle size of the polymer fine particles (B) in the composition of the present invention using a particle size measuring device utilizing light scattering.

  In addition, “stable dispersion” of the polymer fine particles (B) means that the polymer fine particles (B) are not regularly aggregated, separated or precipitated in the vinyl monomer (A), and are regularly Means a state of being dispersed over a long period of time under the conditions, and the distribution of the polymer fine particles (B) in the vinyl monomer (A) is not substantially changed. It is preferable that “stable dispersion” can be maintained even if the composition is heated within a range where there is no danger and the viscosity is lowered and stirred.

  100% by weight of the vinyl monomer (A) according to the present invention is mainly composed of one or more monomers selected from the group consisting of (meth) acrylate monomers and urethane-modified (meth) acrylates, that is, 50%. It is necessary to contain more than wt%.

  It is preferable that the coating composition of this invention contains 0-12 weight part of photoinitiators with respect to 100 weight part of said vinyl monomers (A). This photopolymerization initiator is a compound capable of generating radicals upon irradiation with active energy rays such as ultraviolet rays, visible rays, and electron beams, and is also called a photoradical initiator. When free radicals are generated by the radical polymerization initiator, a carbon-carbon unsaturated double bond polymerization reaction (including a cross-linking reaction) in the composition of the present invention occurs, and the composition is cured to form a coating film. Function as. When the coating composition of the present invention is cured by electron beam (EB), the coating composition of the present invention can be cured without this photopolymerization initiator.

  The active energy ray-curable coating composition of the present invention contains a photopolymerization initiator as described above, and preferably contains a photosensitizer together with such a photopolymerization initiator.

<Vinyl monomer (A)>
As described above, the vinyl monomer (A) according to the present invention is a monomer selected from the group consisting of (meth) acrylic acid ester monomers, urethane-modified (meth) acrylates, and other vinyl monomers.

  In this specification, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester.

((Meth) acrylic acid ester monomer)
Examples of the (meth) acrylic acid ester-based monomer include (meth) acrylate monomer (AA1) having one (meth) acryloyloxy group in the molecule, and two or more (meth) acryloyloxy groups in the molecule ( Although a meth) acrylate monomer (AA2) can be illustrated, it is preferable that AA2 with large active energy ray curability in the air is more than AA1. That is, when the (meth) acrylic acid ester monomer composed of AA1 and AA2 described above is a main component, the main component is preferably AA2.

  Examples of the (meth) acrylate monomer (AA1) having one (meth) acryloyloxy group in the molecule include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and hexyl. In addition to chain alkyl (meth) acrylates such as (meth) acrylate and isodecyl acrylate, alicyclic alkyl (meth) acrylates such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate are also included. Alkyloxy (meth) acrylate such as 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2-hydroxyethyl In addition to hydroxyl group-containing (meth) acrylates such as acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate, allyl ( Examples include (meth) acrylate having an ethylenically unsaturated double bond such as (meth) acrylate.

  Among the (meth) acrylate monomers (AA2) having two or more (meth) acryloyloxy groups in the molecule, those having two are ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexane In addition to diol di (meth) acrylate and cyclohexanedimethanol di (meth) acrylate, polyethylene glycol di (meth) acrylates include triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, and tetraethylene glycol di Examples include (meth) acrylate and polyethylene glycol (600) di (meth) acrylate.

  Further, among the AA2, as (A) having three (meth) acrylate groups, alkoxylated trimethylolpropane tris such as trimethylolpropane tri (meth) acrylate and trimethylolpropane triethoxytri (meth) acrylate are used. (Meth) acrylates, glycerol propoxytri (meth) acrylate, pentaerythritol tri (meth) acrylate, di (trimethylolpropane) tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (2-hydroxyethyl) Examples include isocyanurate tri (meth) acrylate.

  Among these (meth) acrylic acid ester monomers, from the viewpoint of industrial use frequency, isobornyl acrylate, isodecyl acrylate, tetrahydrfurfuryl acrylate, phenoxyethyl acrylate, hydroxypropyl (meth) acrylate, Hexanediol diacrylate (HDODA), triethylene glycol di (meth) acrylate, tripropylene glycol diacrylate (TRPGDA), tetraethylene glycol di (meth) acrylate, trimethylolpropane triacrylate (TMPTA), trimethylolpropane triethoxytri Acrylate (TMPTTETA), glycerol propoxytriacrylate, pentaerythritol triacrylate, di (trimethylolpropane) La acrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate is more preferable.

(Urethane modified (meth) acrylate)
The urethane-modified (meth) acrylate according to the present invention has a weak anaerobic property and has a property of being difficult to undergo radical polymerization inhibition even in an oxygen-existing atmosphere. In the active energy ray-curable coating composition of the present invention, , You can take advantage of this property. Among 100% by weight of the vinyl monomer (A), 0 to 90% by weight of the urethane-modified (meth) acrylate according to the present invention may be included.

  The urethane-modified (meth) acrylate according to the present invention includes (1) a polyisocyanate, (2) a hydroxyl group-containing (meth) acrylic acid ester, and (3) a polyester having a hydroxyl group, a polyether having a hydroxyl group, if necessary. A urethane (meth) acrylate obtained by reacting a compound having a hydroxyl group in the molecule such as acrylic polyol and polyvinyl alcohol is preferred.

  The above polyisocyanate can be used as long as it has a compound having at least two isocyanate groups in the molecule, but tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, hydrogenated tolylene diene. Preferred are divalent isocyanates such as isocyanate, hydrogenated 4,4′-diphenylmethane diisocyanate, lysine diisocyanate methyl ester, 2,2,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, and their dimers or trimers. .

  The polyester having a hydroxyl group is an ester compound of one or more polyhydric alcohols and one or more polybasic acids. Here, the polyhydric alcohol may be an adduct of an alkylene oxide or an adduct of a cyclic ester (for example, caprolactone). As the polyhydric alcohol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, ethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, glycerin, Examples include pentaerythritol and dipentaerythritol. Examples of the polybasic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, isophthalic acid, terephthalic acid, phthalic anhydride, and trimellitic acid.

  A preferable hydroxyl group-containing polyether may be a hydroxyl group-containing polyether obtained by adding one or more alkylene oxides and / or a cyclic ester (for example, caprolactone) to a polyhydric alcohol. Examples of the polyhydric alcohol include those that can be used for the hydroxyl group-containing polyester.

  Preferred as the hydroxyl group-containing (meth) acrylate is an ester compound composed of a polyhydric alcohol and (meth) acrylic acid or methacrylic acid, and has one or more hydroxyl groups in the molecule. The polyhydric alcohol here may be an adduct of an alkylene oxide or an adduct of a cyclic ester (for example, caprolactone), and the same one as in the case of the hydroxyl group-containing polyester can be used.

  Preferred hydroxyl group-containing (meth) acrylates include 2-hydroxyethyl (meth) acrylate, 1-methyl-2-hydroxyethyl (meth) acrylate, glycerin di (meth) acrylate, ethylene oxide-added glycerin di (meth) acrylate, and propylene oxide. Addition glycerin di (meth) acrylate, ε-caprolactone addition glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, ethylene oxide addition trimethylolpropane di (meth) acrylate, propylene oxide addition trimethylolpropane di (meth) acrylate , Ε-caprolactone-added trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene oxide-added pentaerythritol Thritol tri (meth) acrylate, propylene oxide-added pentaerythritol tri (meth) acrylate, ε-caprolactone-added pentaerythritol tri (meth) acrylate, ethylene oxide-added pentaerythritol di (meth) acrylate, propylene oxide-added pentaerythritol di (meth) acrylate, ε-caprolactone-added pentaerythritol di (meth) acrylate, pentaerythritol monoethoxylate di (meth) acrylate, ethylene oxide-added pentaerythritol monoethoxylate di (meth) acrylate, propylene oxide-added pentaerythritol monoethoxylate di (meth) acrylate, ε-Caprolactone-added pentaerythritol monoethoxylate di (meth) a Lilate, dipentaerythritol penta (meth) acrylate, ethylene oxide-added dipentaerythritol penta (meth) acrylate, propylene oxide-added dipentaerythritol penta (meth) acrylate, ε-caprolactone-added dipentaerythritol penta (meth) acrylate, dipentaerythritol Monolaurylate tetra (meth) acrylate, ethylene oxide-added dipentaerythritol monolaurate tetra (meth) acrylate, propylene oxide-added dipentaerythritol monolaurate tetra (meth) acrylate, ε-caprolactone-added dipentaerythritol monolaurylate tetra ( (Meth) acrylate, dipentaerythritol dimethacrylate triacrylate, dipen Erythritol monomethacrylate tetraacrylate, dipentaerythritol tetraacrylate methacrylate monoacrylate can be exemplified.

  As the urethane-modified (meth) acrylate according to the present invention, preferably, the above-mentioned (1) polyisocyanate, (2) hydroxyl group-containing (meth) acrylic acid ester, and (3) a hydroxyl group-containing polyester or hydroxyl group as required. The equivalent ratio of isocyanate (NCO) group / hydroxy acid (OH) group to a compound having a hydroxyl group in the molecule, such as polyether or polyvinyl alcohol, is about 0.7 to 1.20, preferably 0.8. It is obtained by reacting in the range of ˜1.05. Furthermore, the molecular weight becomes like this. Preferably it is 500-20,000, More preferably, it is 600-12,000, More preferably, it is 600-6,000. When the molecular weight is in the range of 600 to 3,000, and a urethane-modified (meth) acrylate having 3 or more (meth) acryloyloxy groups in the molecule, a coating film having particularly excellent hardness can be obtained.

(Aromatic vinyl monomers)
Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, alkyl styrene having an alkyl group having 1 to 12 carbon atoms, methoxystyrene, chlorostyrene, bromostyrene, divinylbenzene, phenylstyrene, vinylnaphthalene, and the like. . Of these aromatic vinyl monomers, styrene is more preferable from the viewpoint of industrial use frequency.

(Other vinyl monomers)
The other vinyl monomer is a vinyl monomer other than those belonging to the group consisting of a (meth) acrylic acid ester monomer and a urethane-modified (meth) acrylate, such as an aromatic vinyl monomer or vinyl Examples thereof include a cyan monomer, a (meth) acrylamide monomer, an N-vinylamide monomer, and an allyl ester monomer.

  Examples of such aromatic vinyl monomers include styrene, α-methylstyrene, alkyl styrene having an alkyl group having 1 to 12 carbon atoms, methoxystyrene, chlorostyrene, bromostyrene, divinylbenzene, phenylstyrene, vinylnaphthalene, and the like. Can be mentioned.

  Similarly, examples of such vinyl cyan monomers include (meth) acrylonitrile.

  Further, (meth) acrylamide monomers include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, and N-isopropyl (meth) acrylamide, and N-vinylamide monomers include N-vinylpyrrolidone and N-vinyl. Examples of caprolactam and allyl ester monomers include diallyl phthalate.

<Polymer fine particles (B)>
The polymer fine particle (B) according to the present invention is a polymer fine particle having a core-shell structure comprising at least two layers of an elastic core layer present on the inner side and a shell layer present on the outermost side, and preferably the elastic fine particle thereof. The core layer is made of a rubbery polymer having a glass transition temperature of less than 0 ° C. More preferably, the polymer fine particles (B) according to the present invention are polymers in which a shell layer is formed by graft polymerization of a monomer component capable of graft copolymerization in the presence of an elastic core layer made of such a rubbery polymer. In this case, the elastic core layer has a structure having an elastic core layer and at least one shell layer that is graft-polymerized on the surface and covers the periphery or part of the elastic core layer.

  The shell layer of the present invention has an elastic core layer / shell layer ratio (mass ratio of monomers forming each polymer) in the range of 30/70 to 99/1 with respect to the elastic core layer. Is more preferable, 50/50 to 90/10 is more preferable, and 55/45 to 88/12 is still more preferable. If the elastic core layer / shell layer ratio is off 30/70 and the elastic core layer ratio is decreased, the composition of the present invention may have a high viscosity and may be difficult to handle. Further, if the ratio of the shell layer falls outside 99/1, it tends to cause aggregation when handling the polymer fine particles, which may cause a problem in operability. In addition, the physical properties expected of the cured product of the composition of the present invention may not be obtained.

  As a polymerization method for forming such polymer particles having a core-shell structure, it is preferable to polymerize a polymerizable monomer described later by a known emulsion polymerization method or suspension polymerization method. Moreover, when the polymer fine particle (B) uses a polysiloxane rubber described later as an elastic core, it can also be obtained by a method of forcibly emulsifying after solution polymerization.

(Elastic core layer)
The elastic core layer according to the present invention is preferably a rubbery polymer having properties as a rubber capable of imparting toughness to the cured product according to the present invention. The elastic core layer often has a single layer structure, but may have a multilayer structure. When the elastic core layer has a multilayer structure, the polymer composition of each layer may be different.

  Such a rubbery polymer according to the present invention preferably has a cross-linked structure. When such a cross-linked rubber polymer is used, the rubbery polymer is a vinyl monomer according to the present invention. It does not dissolve in the component (A) and does not dissolve even if it swells even in a solvent that is a good solvent.

  The glass transition temperature (Tg) of the rubber-like polymer is preferably less than 0 ° C., but is preferably −20 ° C. or less, more preferably −45 ° C. or less from the viewpoint of increasing the toughness imparting effect.

  The elastic core layer usually has a spherical shape. In this case, the volume average particle size of the core portion which is the elastic core layer in the polymer fine particles (B) is 1 as the volume average particle size of the polymer fine particles (B). As long as it is in the range of ˜50 μm, it is preferably 1 to 50 μm, more preferably 1 to 20 μm. As described above, the core portion is preferably insoluble in the vinyl monomer (A). In that case, if the cured product of the composition of the present invention is observed using, for example, a transmission electron microscope (TEM), the core portion can be easily obtained. The particle diameter of the part can be confirmed.

  Such a rubber-like polymer is obtained by polymerizing a monomer for forming a rubber-like polymer. Among them, the main monomer, that is, the type of monomer that becomes the first monomer The diene rubber obtained mainly by polymerizing the conjugated diene monomer, the acrylic rubber obtained mainly by polymerizing the (meth) acrylic acid ester monomer, and the polysiloxane rubber may be mentioned. A combination of these or a combination thereof may be used. In addition to the first monomer, the rubber-like polymer-forming monomer may further contain an aromatic vinyl monomer and a vinyl cyan monomer.

  A preferred first monomer for the acrylic rubber is butyl acrylate or 2-ethylhexyl acrylate, and a preferred first monomer for the diene rubber is butadiene, isoprene, or the like.

(Bridge of elastic core layer)
In the elastic core layer according to the present invention, it is preferable that a crosslinked structure is introduced into a polymer component obtained by polymerizing the monomer. The method for introducing the crosslinked structure is not particularly limited, and a generally used method can be employed. For example, as a method for introducing a cross-linked structure into a polymer component obtained by polymerizing the above monomer, a method in which a cross-linkable monomer such as a polyfunctional monomer described later is added to the polymer component and then polymerized is exemplified. It is done. Specifically, the elastic core layer preferably has a gel content of 60% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and 95% by mass or more. It is particularly preferred that As used herein, the gel content refers to when about 1.2 g of crumb obtained by coagulation and drying is immersed in 100 g of toluene and left at 23 ° C. for 24 hours, and then insoluble and soluble components are separated. Means the ratio of the insoluble content to the total amount of the insoluble content and the soluble content.

(Polyfunctional monomer)
The polyfunctional monomer does not include butadiene, and includes alkyl (meth) acrylates having an allyl group such as allyl (meth) acrylate and allyloxyalkyl (meth) acrylate; 1,3-butanediol di (meth) ) Acrylates, 1,4-butanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate and other polyfunctional (meth) acrylates Diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene and the like. Particularly preferred are allyl methacrylate, 1,3-butanediol dimethacrylate, triallyl isocyanurate, 1,4-butanediol di (meth) acrylate, and divinylbenzene.

<Shell layer>
The shell layer according to the present invention improves the compatibility between the polymer fine particles (B) and the vinyl monomer (A), and the polymer fine particles (B) are contained in the curable composition according to the present invention or the cured product thereof. It consists of a shell polymer that plays a role of enabling dispersion in the form of primary particles.

  Such a shell polymer is preferably grafted to the elastic core layer. More precisely, it is preferable that the monomer component used for forming the shell layer is graft-polymerized to the core polymer forming the elastic core layer so that the shell layer and the elastic core layer are substantially chemically bonded. . That is, preferably, the shell polymer is formed by graft polymerization of a monomer (mixture) that is a component of the shell polymer in the presence of the core polymer, and in this way, the core polymer is graft-polymerized. And covers part or all of the core polymer. This polymerization operation is carried out by adding a monomer that is a constituent component of the shell polymer to the core polymer prepared and present in an aqueous polymer latex state and polymerizing it. The primary particle diameter of (B) thus obtained is 1 to 50 μm. Moreover, there is no restriction | limiting in particular in Tg of the polymer which comprises a shell layer, You may be less than 0 degreeC.

Such a shell polymer is obtained by polymerizing a monomer for forming a shell polymer (BS). From the viewpoint of effectively ensuring the primary dispersibility described above,
2 to 90% by weight of at least one monomer (BS-1) selected from the group consisting of alkoxyalkyl (meth) acrylate, hydroxyalkyl (meth) acrylate, and glycidyl (meth) acrylate,
2 to 98% by weight of one or more monomers (BS-2) selected from the group consisting of alkyl (meth) acrylate, styrene, α-methylstyrene, and (meth) acrylonitrile;
Shell polymer of 100% by weight in total of 0 to 10% by weight of polyfunctional vinyl monomer (BS-3) and 0 to 10% by weight of other vinyl monomer (BS-4) copolymerizable with these monomers A copolymer of the forming monomer (BS) is preferred.

  Examples of the combination of the monomer (BS) for forming a shell polymer include (1) an alkoxyalkyl having 2 to 10 carbon atoms and one ether bond by an oxygen atom as the monomer (BS-1). A combination of an alkoxyalkyl (meth) acrylate having a group and an alkyl (meth) acrylate having an alkyl group having 2 to 10 carbon atoms which is a monomer (BS-2), (2) a carbon number which is a monomer (BS-1) A combination of a hydroxyalkyl (meth) acrylate having a hydroxyalkyl group having 2 to 10 and one hydroxyl group, and an alkyl (meth) acrylate having a C2-10 alkyl group as the monomer (BS-2), ( 3) Monomer (BS-1) having 2 to 10 carbon atoms and containing one ether bond by an oxygen atom Alkoxyalkoxyalkyl (meth) acrylates having an alkyl group (m-1), and a monomer (BS-2) (meth) combination with acrylonitrile, etc. can be preferably exemplified.

  Monomer (BS-1), monomer (BS-2), polyfunctional vinyl monomer (BS-3), and other copolymerizable with these monomers in the shell polymer-forming monomer (BS) From the viewpoint of obtaining a more stable curable composition, the ratio of vinyl monomer (BS-4) is 2 to 90% by weight of monomer (BS-1), 2 to 98% by weight of monomer (BS-2), polyfunctional It is preferable to use 0 to 10% by weight of the functional vinyl monomer (BS-3) and 0 to 10% by weight of the other vinyl monomer (BS-4) copolymerizable with these monomers, and a crosslinked structure is introduced into the shell layer. From the viewpoint of sufficiently preventing the swelling described above, the shell polymer-forming monomer (BS) containing 0.1 to 5% by weight of a polyfunctional vinyl monomer (BS-3) as an essential component is used. Is more preferable.

  Examples of the alkoxyalkyl (meth) acrylate in the monomer (BS-1) include 2-methoxyethyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, (meth Preferred examples include tetrahydrofurfuryl acrylate and 2-phenoxyethyl (meth) acrylate.

  Preferred examples of the hydroxyalkyl (meth) acrylate in the monomer (BS-1) include 2-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate.

  Examples of the alkyl (meth) acrylate having an alkyl group having 2 to 10 carbon atoms in the monomer (BS-2) include ethyl (meth) acrylate, butyl (meth) acrylate, tertiary butyl (meth) acrylate, A preferred example is cyclohexyl (meth) acrylate.

  Examples of the polyfunctional vinyl monomer (BS-3) include allyl (meth) acrylate, 1,3-butanediol di (meth) acrylate, diallyl phthalate, (poly) ethylene glycol di (meth) acrylate, and trimethylol. Propane (tri) acrylate, triallyl isocyanurate, and tris (2-hydroxyethyl) isocyanurate triacrylate can be preferably exemplified.

  Examples of other vinyl monomers (BS-4) copolymerizable with these monomers include (meth) acrylamide monomers, allyl ester monomers, N-vinylpyrrolidone monomers, (meth) acrylic acid monomers, and the like. . As the (meth) acrylamide monomer, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide is used, and as the allyl ester monomer, diallyl phthalate is an N-vinylpyrrolidone monomer. Examples thereof include N-vinylpyrrolidone and N-vinylcaprolactam, and examples of the meth) acrylic acid monomer include (meth) acrylic acid, crotonic acid, itaconic acid, cinnamic acid, maleic anhydride, and butenetricarboxylic acid.

(Recovery of polymer fine particle (B) from aqueous medium)
Since the polymer fine particles (B) are obtained in a state of being dispersed in an aqueous medium, an operation for recovering them is required. The operation is not particularly limited as long as the dispersion to the primary particles is not hindered, but the so-called master batch (T) in which the polymer fine particles (B) are contained as primary particles in the vinyl monomer (A) is used. It is preferable.

  Such a master batch (T) may be used as it is to obtain an active energy ray-curable composition, and a vinyl monomer (A) may be further added as necessary.

  The master batch (T), for example, extracts polymer fine particles (B) from an aqueous dispersion of polymer fine particles (B) into an organic solvent, and then mixes with the vinyl monomer (A) to volatilize the organic solvent and moisture. Is obtained. By measuring the particle size before and after the recovery operation, it can be confirmed that the polymer fine particles (B) are dispersed in the primary particles.

<Photopolymerization initiator>
The photopolymerization initiator according to the present invention can be selected from those that undergo irradiation of active energy rays such as ultraviolet rays, electron beams, and visible light to radically polymerize the vinyl monomer (A).

  Examples of such photopolymerization initiators include benzophenones such as benzophenone and 4,4-bis (N, N′-dimethylamino) benzophenone, and benzoins such as benzoin and benzoin alkyl ether (alkyl = methyl, ethyl, isopropyl). , Acetophenones such as 2,2-dimethoxyacetophenone and 1,1-dichloroacetophenone, benzyl ketals such as benzyldimethyl ketal (Irgacure 651, manufactured by Ciba Specialty Chemicals), 2-methylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone Anthraquinones such as phenyl di (2,4,6-trimethylbenzoyl) phosphine oxide (Irgacure 819, manufactured by Ciba Specialty Chemicals), Benzoylphosphine oxides such as 1,4,6-trimethylbenzoyl-diphenylphosphine oxide, triphenylphosphine, 1-hydroxycyclohexyl phenyl ketone (eg, Irgacure 184, manufactured by Ciba Specialty Chemicals), 2-hydroxyisopropylphenyl ketone, 2- Examples include α-hydroxyphenyl ketones such as hydroxy-1- [4- (2-hydroxyethoxy) phenyl] -1-propanone, thioxanthones such as thioxanthone and 2-chlorothioxanthone, camphorquinone and the like, acridine derivatives, Phenazine derivatives, quinoxaline derivatives, and the like can also be used.

  Such a photopolymerization initiator is not necessarily required when the composition of the present invention is cured with an electron beam, but is necessary when cured with ultraviolet rays or visible light. The compounding quantity of a preferable photoinitiator is 0.1-12 weight part with respect to 100 weight part of vinyl monomers (A). The adhesive composition satisfying the requirements of the present invention is preferably 0.3 to 8 parts by weight as long as it has good light transmittance and does not particularly block or scatter ultraviolet rays or visible light. A combination of these photopolymerization initiators can also be used.

<Photosensitizer>
Furthermore, you may use together with these photoinitiators the photosensitizer used combining conventionally. A photosensitizer is not activated by irradiation with ultraviolet rays or the like by itself, but when used together with a photopolymerization initiator, it has a function of making radical polymerization easier to proceed than in the case of a photopolymerization initiator alone. Have. Examples of such photosensitizers include amines such as n-butylamine, triethylamine, N-methyldiethanolamine, piperidine, N, N-dimethylaniline, triethylenetetramine, diethylaminoethyl (meth) acrylate, and O-tolylthiourea. Illustrative examples include such urea compounds, sulfur compounds such as s-benzyl-isothiuronium-p-toluenesulfinate, nitriles such as N, N-dimethyl-p-aminobenzonitrile, and phosphorus compounds such as sodium diethylthiophosphate. And 0 to 6 parts by weight are preferably added to the composition of the present invention.

<Curing>
For curing the coating composition of the present invention, active energy rays can be used. Active energy rays are visible light, ultraviolet rays, microwaves, high frequencies, and ionizing radiation such as electron beams, X-rays, α rays, β rays, and γ rays, but release substances that initiate polymerization. Any energy species is acceptable if possible. For example, in the case of ultraviolet to visible light, a high-pressure mercury lamp, a metal halide lamp, laser light, LED light, sunlight, or the like can be used. Typically, it can be cured by irradiating an integrated light amount of 1 to 9,000 mJ / cm2. Curing can be performed in an air atmosphere, an inert gas atmosphere, or a mixed gas atmosphere thereof. However, curing in an atmosphere with a low oxygen concentration promotes the formation of a crosslinked structure and reduces the inhibition of curing. From such viewpoints, there is a tendency to give a coating film with excellent quality.

  In the case of curing with a photoelectron beam (EB), a photopolymerization initiator is not always necessary. Typically, an electron beam generator having an acceleration voltage of 100 to 500 kV can be used. When curing, it can be cured in an air atmosphere, an inert gas atmosphere, or a mixed gas atmosphere thereof. However, the possibility of generation of ozone and nitrogen oxides by electron beams and the lower the oxygen concentration, the more the polymerization is inhibited. From the viewpoint of low oxygen content, it is preferable that the oxygen concentration is low.

<Others>
The coating method of the coating composition of the present invention is not particularly limited, and the bar coating method, the micro bar coating method, the spray method, the dip (dipping) method, the roll coater method, the roll knife coating method, and the spin coating method. , Slide coating method, curtain coating method, meniscus coater method, bead coater method, gravure coating method, die coating method, rod coating method, screen printing method, flexographic printing method, offset printing method, gravure printing method, etc. be able to.

  Moreover, the composition of this invention can also be diluted with an organic solvent suitably, and can be used. There is no limitation on the usable organic solvent as long as it is a solvent that can be mixed with the vinyl monomer (A) and does not significantly impair the handleability of the coating composition of the present invention. Preferably, it is preferable to use an organic solvent in such a range that it can be mixed with the vinyl monomer (A) and the polymer fine particles (B) are not separated from the coating composition of the present invention and precipitation or levitation does not occur. . More preferably, it is preferable to use an organic solvent as long as it can be mixed with the vinyl monomer (A) and does not impair the state where the polymer fine particles (B) are dispersed in the primary particles. The amount of the organic solvent used is not particularly limited as long as the above requirements are satisfied. Specific examples of organic solvents include esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, ethanol, isopropyl alcohol, butanol, methyl glycol, ethyl cellosolve, methyl cellosolve, butyl cellosolve, etc. Examples include alcohols, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol, ketones such as acetone, amides such as N-methylpyrrolidone, N, N-dimethylformamide, and ethers such as tetrahydrofuran, dioxane, dioxolane, etc. , Halogenated hydrocarbons such as methylene chloride and dichloroethane, dimethyl sulfoxide, propylene carbonate, and the like can also be used. You may mix and use these suitably.

  The coating composition of the present invention can be used by being applied to various substrates, and in addition to resin materials such as polyester, polycarbonate, acrylic polymer, cycloolefin polymer, and cellulose acylate, It can be used by applying to the surface of not only the cured resin but also wood, metal, etc.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to these.

(Evaluation method)
(1) Volume average particle diameter The volume average particle diameter of the polymer fine particles (B) was measured with a particle diameter measuring device (Microtrac (registered trademark) UPA manufactured by Nikkiso Co., Ltd.).

(2) Total light transmittance, haze It measured with NDH-300A by Nippon Denshoku Industries Co., Ltd. using the film with a cured coating film as a sample. It can be said that the larger the haze value, the higher the light diffusibility.

(3) Glossiness Glossiness at an incident angle of 60 degrees was measured with a VG-2000 manufactured by Nippon Denshoku Industries Co., Ltd. using a film with a cured coating film as a sample. It can be said that the lower the glossiness, the higher the matteness.

(4) Bending resistance test (cylindrical mandrel method)
Using a film with a cured coating film as a sample, it was carried out at 23 ° C. in accordance with JISK5600. Using a round bar having a diameter (Φ) of 10 mm, the presence or absence of cracks on the surface of the coated film after bending was observed.

(5) Pencil hardness Using a film with a cured coating film as a sample, the hardness of the coating film surface was evaluated according to JIS K5600 at a load of 500 g and 23 ° C. Evaluation result: 2B, B, HB, F, H, 2H,... Indicate that the surface is hard and hard to damage.

(6) Appearance The surface of the coating film was visually observed to check for the presence of particulate matter. The case where no particulate matter was observed was marked with ◯, and the case where particulate matter was seen was marked with ×.

(7) Particle sedimentation property The presence or absence of particle sedimentation after leaving the compositions used in Examples and Comparative Examples for 24 hours was visually observed.

[Preparation of acrylic core-shell polymer fine particles (B1)]
6.75 parts by weight of butyl acrylate, 0.14 parts by weight of allyl methacrylate, 0.04 parts by weight of 1,3-butylene glycol dimethacrylate, 0.07 parts by weight of stearyl methacrylate, and 0.2 weights of lauroyl peroxide A mixture in which parts were uniformly dissolved was prepared. To this mixture, a solution consisting of 10 parts by weight of water and 0.02 part by weight of sodium dodecylbenzenesulfonate was added and mixed. K. An O / W emulsion was prepared by applying mechanical shearing at 7,000 rpm for 10 minutes with Robomix (manufactured by Tokushu Kika Kogyo Co., Ltd.).

To a glass reactor charged with 210 parts by weight of water, 0.01 parts by weight of sodium nitrite, and 0.05 parts by weight of sodium dodecylbenzenesulfonate, the dispersion containing this prepared emulsion was added, The temperature of the system is raised to 65 ° C. while stirring at 65 ° C.
And stirred for 30 minutes.

Next, 0.2 parts by weight of sodium dodecylbenzenesulfonate was added to the system, and then 61.4 parts by weight of butyl acrylate, 1.3 parts by weight of allyl methacrylate, 1,3-dimethacrylic acid 1,3-
0.3 part by weight of butylene glycol was continuously added over 3 hours. Thereafter, the system temperature was kept at 65 ° C. and stirred for 1 hour.
Furthermore, after adding 0.2 parts by weight of sodium dodecylbenzenesulfonate to the system, 7.5 parts by weight of butyl acrylate, 15 parts by weight of ethyl acrylate, 7.5 parts by weight of 2-methoxyethyl acrylate, allyl methacrylate 0.7 parts by weight were continuously added over 1.5 hours. Thereafter, the system temperature was kept at 65 ° C. and stirred for 1 hour to obtain an aqueous latex. The solid content concentration was 31%, and the polymerization conversion rate was 99%. A part of the polymer fine particles (B1) in an aqueous latex state was taken and diluted with water, and the volume average particle size was measured with a particle size measuring device (Microtrac UPA manufactured by Nikkiso Co., Ltd.) and found to be 2.0 μm. .

[Preparation of acrylic core-shell polymer fine particles (B2)]
Under a nitrogen atmosphere, in a 2 L glass reaction vessel, 220 parts by weight of water, 0.0025 parts by weight of sodium dodecylbenzenesulfonate, 0.025 parts by weight of tripotassium phosphate, 0.0008 parts by weight of iron (II) sulfate hexahydrate. Parts, 0.0032 parts by weight of EDTA (ethylenediaminetetraacetic acid), and 0.1 parts by weight of sodium formaldehyde sulfoxylate were charged and stirring was started. After setting to 40 degrees, a mixture of 6.82 parts by weight of butyl acrylate, 0.14 parts by weight of allyl methacrylate, and 0.04 parts by weight of 1,3-butylene glycol dimethacrylate was added. Immediately thereafter, 0.004 part by weight of cumene hydroperoxide was added and held for 1 hour. Next, 0.2 parts by weight of sodium dodecylbenzenesulfonate was added to the system, and then 61.4 parts by weight of butyl acrylate, 1.3 parts by weight of allyl methacrylate, and 0.3 parts by weight of 1,3-butylene glycol dimethacrylate. A mixture of 0.03 part by weight of cumene hydroperoxide was continuously added over 3 hours. Furthermore, after adding 0.2 parts by weight of sodium dodecylbenzenesulfonate to the system, 7.5 parts by weight of butyl acrylate, 15 parts by weight of ethyl acrylate, 7.5 parts by weight of 2-methoxyethyl acrylate, allyl methacrylate A mixture of 0.7 parts by weight and 0.02 parts by weight of t-butyl hydroperoxide was continuously added over 1.5 hours. Thereafter, the mixture was stirred for 1 hour to obtain an aqueous latex. The solid content concentration was 31%, and the polymerization conversion rate was 99%. A part of the polymer fine particles (B1) in an aqueous latex state was taken and diluted with water, and the volume average particle size was measured with a particle size measuring device (Microtrac UPA manufactured by Nikkiso Co., Ltd.) and found to be 0.4 μm. .

[Preparation of powdery polymer (B1 ′)]
While stirring 1000 g of an aqueous latex containing polymer fine particles (B1) at room temperature, 200 g of a 10% calcium chloride aqueous solution was added thereto and coagulated. The slurry was heated to 70 ° C., then dehydrated, washed with water, and dried to obtain a coarse granular polymer (B1 ′).

[Preparation of Composition T1 Containing Polymer Fine Particles (B1)]
After mixing 1000 g of aqueous latex containing polymer fine particles (B1) and 1000 g of methyl acetate, 700 g of water was further added to reprecipitate polymer fine particles (B). After separating the liquid phase from the reprecipitate, 1300 g of methyl acetate was added to the reprecipitate and stirred at room temperature for 90 minutes. This mixture was mixed with 310 g of pentaerythritol triacrylate (PETA) as the vinyl monomer (A), and then methyl acetate was distilled off under reduced pressure, whereby polymer fine particles were added to 100 parts by weight of pentaerythritol triacrylate (PETA). A composition T1 (620 g) in which 100 parts by weight of the acrylic polymer fine particles (B1) as (B), that is, 50% by weight of the polymer fine particles (B) were dispersed, was obtained.

  This composition T1 was diluted with methyl ethyl ketone (MEK), and the volume average particle size of the polymer fine particles (B) was measured again with a particle size measuring device (Microtrac UPA manufactured by Nikkiso Co., Ltd.). At 2.0 μm, the particle size distribution was the same as (B1) in the aqueous latex state.

  Furthermore, in this composition T1, the dispersion state of the polymer fine particles (B1) did not change even after being left for 3 months in a cool and dark place protected from light.

[Preparation of Composition T2 Containing Polymer Fine Particles (B2)]
After mixing 1000 g of aqueous latex containing polymer fine particles (B2) and 1000 g of methyl acetate, 700 g of water was further added to reprecipitate polymer fine particles (B). After separating the liquid phase from the reprecipitate, 1300 g of methyl acetate was added to the reprecipitate and stirred at room temperature for 90 minutes. This mixture was mixed with 310 g of pentaerythritol triacrylate (PETA) as the vinyl monomer (A), and then methyl acetate was distilled off under reduced pressure, whereby polymer fine particles were added to 100 parts by weight of pentaerythritol triacrylate (PETA). A composition T2 (620 g) in which 100 parts by weight of the acrylic polymer fine particles (B1) as (B), that is, 50% by weight of the polymer fine particles (B) were dispersed, was obtained.

  The composition T2 was diluted with methyl ethyl ketone (MEK), and the volume average particle size of the polymer fine particles (B) was measured again with a particle size measuring device (Microtrac UPA manufactured by Nikkiso Co., Ltd.). At 0.4 μm, the particle size distribution was similar to (B1) in the aqueous latex state.

  Further, in this composition T2, the dispersion state of the polymer fine particles (B1) did not change even after being left for 3 months in a cool and dark place protected from light.

Example 1
T1 (50 g) obtained above, pentaerythritol triacrylate (PETA) (25 g), 3 ethoxylated trimethylolpropane triacrylate (EO3TMPTA) (25 g), methyl ethyl ketone (MEK) (20 g), 1-hydroxycyclohexyl phenyl ketone ( 5 g) was mixed to obtain a polymer fine particle-containing active energy ray-curable coating composition. This mixture is a mixture comprising 25 g of polymer fine particles B1, 50 g of PETA, and 25 g of EO3TMPTA.

  The coating composition was applied on a 150 × 100 mm × 125 μm thick PET (polyethylene terephthalate) film using a bar coater (# 20) and then dried at 100 ° C. for 2 minutes. The sample was passed through the sample at a conveyor speed of 4.0 m / min and cured under irradiation of a 120 W / cm metal halide lamp using a UV irradiation device (ECS-301, manufactured by I-Graphics). The evaluation results are shown in the table.

(Comparative Example 1)
25 g of techpolymer MBX-5 (manufactured by Sekisui Plastics Co., Ltd., average particle size 5 μm), pentaerythritol triacrylate (PETA) (25 g), 3 ethoxylated trimethylolpropane tri, which are commercially available powdery acrylic polymer particles Acrylate (EO3TMPTA) (25 g), methyl ethyl ketone (MEK) (20 g), and 1-hydroxycyclohexyl phenyl ketone (5 g) were mixed to obtain a polymer fine particle-containing active energy ray-curable coating composition. This mixture is a mixture comprising 25 g of polymer fine particles, 50 g of PETA, and 25 g of EO3TMPTA.

  This coating composition was applied and cured in the same manner as in Example 1. The evaluation results are shown in the table.

(Comparative Example 2)
25 g of Tospearl 120 (Momentive Performance Materials, average particle size 2 μm), pentaerythritol triacrylate (PET) (25 g), 3 ethoxylated trimethylolpropane triacrylate, which are commercially available powdery silicone polymer fine particles (EO3TMPTA) (25 g), methyl ethyl ketone (MEK) (20 g), and 1-hydroxycyclohexyl phenyl ketone (5 g) were mixed to obtain a polymer fine particle-containing active energy ray-curable coating composition. This mixture is a mixture comprising 25 g of polymer fine particles, 50 g of PETA, and 25 g of EO3TMPTA.

  This coating composition was applied and cured in the same manner as in Example 1. The evaluation results are shown in the table.

(Comparative Example 3)
T2 (50 g) obtained above, pentaerythritol triacrylate (PETA) (25 g), 3 ethoxylated trimethylolpropane triacrylate (EO3TMPTA) (25 g), methyl ethyl ketone (MEK) (20 g), 1-hydroxycyclohexyl phenyl ketone ( 5 g) was mixed to obtain a polymer fine particle-containing active energy ray-curable coating composition. This mixture is a mixture comprising 25 g of polymer fine particles B2, 50 g of PETA, and 25 g of EO3TMPTA.

  This coating composition was applied and cured in the same manner as in Example 1. The evaluation results are shown in the table.

(Comparative Example 4)
25 g of B1 ′ obtained by pulverizing B1 obtained above, pentaerythritol triacrylate (PETA) (25 g), 3 ethoxylated trimethylolpropane triacrylate (EO3TMPTA) (25 g), methyl ethyl ketone (MEK) (20 g), 1 -Hydroxycyclohexyl phenyl ketone (5 g) was stirred and mixed for 1 day, but B1 'was not dispersed in the mixture and a lump was left as it was.

  From the results of the above Example 1, Comparative Example 1 and Comparative Example 2, the active energy ray-curable coating composition of the present invention containing core-shell type polymer fine particles (B) and dispersed in primary particles (Examples) It can be seen that 1) is excellent in bending resistance while maintaining light diffusibility, matteness and hardness, and polymer fine particles are difficult to settle.

  Moreover, from the results of Example 1 and Comparative Example 3, it can be seen that Comparative Example 3 having a small volume average particle diameter is inferior in light diffusibility and matting property.

  Further, from the results of Example 1 and Comparative Examples 1, 2, and 4, the composition (Example 1) in which the polymer fine particles (B) were dispersed in the vinyl monomer (A) without being powdered was powdered. It can be seen that the dispersibility is good compared to Comparative Examples 1, 2, and 4 using the polymer fine particles.

Claims (5)

A core / shell graft copolymer having 100 parts by weight of a vinyl monomer (A) and a volume average particle diameter of 1 to 20 μm and comprising at least two layers of an elastic core layer and an outermost shell layer An active energy ray-curable coating composition containing 1 to 200 parts by weight of polymer fine particles (B), wherein the vinyl monomer (A) is a (meth) acrylic acid ester monomer, a urethane-modified (meth) acrylate, A polymer fine particle-containing vinyl monomer composition comprising as a main component one or more monomers selected from the group consisting of the above, wherein the polymer fine particles (B) are primarily dispersed in the vinyl monomer (A). An active energy ray-curable coating composition containing the same. The shell layer is composed of 2 to 90% by weight of one or more monomers (BS-1) selected from the group consisting of alkoxyalkyl (meth) acrylate, hydroxyalkyl (meth) acrylate, and glycidyl (meth) acrylate, and alkyl ( One or more monomers (BS-2) 2 to 98% by weight selected from the group consisting of (meth) acrylate, styrene, α-methylstyrene, and (meth) acrylonitrile; and polyfunctional vinyl monomer (BS-3) 0 Copolymer of monomer (BS) of 100% by weight in total of 10% by weight and 10% by weight of other vinyl monomers (BS-4) copolymerizable with these monomers The active energy ray-curable coating composition according to claim 1. The elastic core layer of the polymer particles (B) is an active energy ray-curable coating composition according to any one of 請 Motomeko 1,2 glass transition temperature ing a rubber-like polymer of less than 0 ° C.. The polymer fine particle-containing vinyl monomer composition is obtained by extracting polymer fine particles from an aqueous dispersion of polymer fine particles into an organic solvent, and then mixing with the vinyl monomer to volatilize the organic solvent and water. 4. The active energy ray-curable coating composition according to any one of 3 above. The coating film formed by hardening | curing the active energy ray-curable coating composition in any one of Claims 1-4 .