JPWO2015178501A1 - Polymer fine particle composition and its use as a light diffusing agent - Google Patents

Abstract

It is an object of the present invention to provide an acrylic fine particle composition having a high refractive index that contributes to the enhancement of the function of a light diffusion sheet base material used for a liquid crystal display device and the like aiming at thinning and high brightness. Average particle diameter obtained by copolymerization reaction of 98-70% by mass of o-phenylphenol (meth) acrylate compound and 2-30% by mass of divinyl compound having a molecular weight smaller than the above compound (100% by mass). This is solved by using a polymer fine particle composition in the range of 1 to 5 μm and the refractive index of 1.60 to 1.62.

Description

  The present invention relates to a polymer fine particle composition and use thereof. Specifically, the present invention relates to a (meth) acrylic crosslinked fine particle copolymer composition having an average particle diameter of 2 to 5 μm and a refractive index of 1.60 or more. In addition to the copolymer, the composition contains additives such as a polymerization stabilizer and a surfactant. Then, for example, the polymer fine particles are arranged in a concavo-convex shape using a binder on the surface of the acrylic light diffusing sheet, or are contained in the sheet to cause diffusion of transmitted light due to a difference in refractive index. Regarding usage.

  In a display device having a light source such as a liquid crystal display device, a light diffusion sheet is used in order to cause the light source disposed on the back of the screen to function as a surface light source. As this light diffusion sheet, for example, there is one in which a transparent (meth) acrylic resin sheet is used as a base material and fine particles having higher refraction are applied or combined.

  Initially, inorganic particles such as silica and titanium dioxide were used as the fine particles. However, non-uniform dispersion due to insufficient affinity with the resin, white turbidity or translucency of the product due to the material itself being opaque, brightness reduction, and scratches when contacting with other flexible materials As a result, polymer-based fine particle compositions having flexibility have become mainstream.

  The (meth) acrylic crosslinked fine particles are a typical example, and various fine particle compositions have been proposed up to a refractive index of around 1.59 (for example, Patent Document 1). However, a polymer fine particle composition having a refractive index of 1.60 to 1.62 and an average particle size in the range of 2 to 5 μm is required in order to meet demands for further thinning and high brightness of display devices in recent years. However, no specific proposal has been made for (meth) acrylic crosslinked fine particles. In addition, although the microparticles | fine-particles exceeding refractive index 1.60 are known, these are not (meth) acrylic-type materials (for example, patent documents 2-3).

JP 2012-23036 A JP-A-11-269419 JP 2001-348477 A

  The present invention is used in a liquid crystal display device aiming at thinning and high brightness, for example, (meth) acrylic resin (meaning acrylic resin, methacrylic resin, the same shall apply hereinafter), a high function of a light diffusion sheet base material An object of the present invention is to provide a high-refractive-index crosslinked acrylic fine particle composition that is effective for the preparation.

式中、Ｒは、Ｈ、または、−ＣＨ３、である。The first of the present invention is 98 to 70% by mass of an ethoxylated o-phenylphenol (meth) acrylate compound represented by the chemical formula (1), 2 to 30% by mass of a divinyl compound having a molecular weight smaller than the chemical formula (1) ( It is related with the polymer fine particle composition formed by carrying out a copolymer reaction.

In the formula, R is H or —CH 3.

  The second of the present invention relates to the first polymer fine particle composition of the present invention in which the average particle diameter of the polymer fine particles is in the range of 2 to 5 μm and the refractive index is in the range of 1.60 to 1.62.

  A third aspect of the present invention relates to the polymer fine particle composition according to the first or second aspect of the present invention, wherein the divinyl compound contains divinylbenzene.

  A fourth aspect of the present invention relates to a light scattering sheet comprising the polymer fine particle composition according to any one of the first or first to third aspects of the present invention.

  A fifth aspect of the present invention relates to the use of the polymer fine particle composition according to any one of the first to third aspects of the present invention as a light scattering agent.

The sixth of the present invention relates to a method for producing a polymer fine particle composition, which comprises the following steps:
98 to 70% by mass of ethoxylated o-phenylphenol acrylate, 2 to 30% by mass of divinyl compound having a molecular weight smaller than that of ethoxylated o-phenylphenol (meth) acrylate (molecular weight 268 or 282) (both 100% by mass) A step of emulsifying the oil phase and the aqueous phase comprising an O / W emulsion, and a subsequent suspension polymerization step of the O / W emulsion. Here, the polymer fine particle composition has an average particle diameter of 2 to 5 μm and a refractive index of 1.60 to 1.62.

  7th of this invention is related with the manufacturing method of the polymer fine particle composition as described in 6th of this invention characterized by a divinyl compound containing divinylbenzene.

  By using the polymer fine particle composition according to the present invention, for example, by applying to a (meth) acrylic transparent resin material substrate, or by combining (by laminating a thin film, kneading into a substrate, etc.), A light diffusing highly functional optical material having excellent light diffusibility can be obtained.

  The polymer fine particle composition according to the present invention comprises 98 to 70% by mass of an ethoxylated o-phenylphenol (meth) acrylate compound represented by the chemical formula (1) and a molecular weight smaller than that of the compound represented by the chemical formula (1). 2 to 30% by mass of the divinyl compound (100% by mass in total) is cross-linked.

式中、Ｒは、Ｈ、または、−ＣＨ３、である。

In the formula, R is H or —CH 3.

  The compound represented by the chemical formula (1) can be synthesized by a known method for synthesizing (meth) acrylic acid ester, and R in formula (1) is H (hydrogen). The acrylate can be obtained from the market under the trade name “A-LEN-10” (manufactured by Shin-Nakamura Chemical Co., Ltd.).

  The compound represented by the chemical formula (1) is known to have a large refractive index. Specific usage methods include a monomer for a photocurable resin (Shin-Nakamura Chemical Co., Ltd. website) and an intraocular lens (for example, Patent Publication 2006). No. 249381), a specific method of using the high refractive index fine particle composition as a raw material has not yet been clarified.

  The compound of the chemical formula (1) is relatively poor in hydrophilicity and has high viscosity in the acrylate compound. In the O / W type emulsion, usually, a large oil phase (or oil droplets, the same applies hereinafter) is formed, and the oil phase is likely to associate. Usually, a surfactant is added in order to reduce the oil phase in the O / W emulsion to 5 μm or less. However, a surfactant exhibiting a remarkable and remarkable effect is found in the compound of the chemical formula (1). However, it is necessary to add a large amount of a surfactant. In this case, however, the post-treatment is complicated, and the remaining surfactant may impair the function of the light scattering agent of the particles. Further, according to the study by the present inventors, the compound represented by the chemical formula (1) is not easily divided or refined even when a normal amount of a surfactant is used in combination with vigorous stirring. Moreover, even after fragmentation / miniaturization, the particles are easily associated and returned to large particles, and the oil phase does not become 5 μm or less.

  From the compound of the chemical formula (1), the compound of the formula (1) (wherein R is hydrogen, the molecular weight is 268, R is CH3, 282) 98 to 70% by mass, and the compound of the chemical formula (1) By copolymerizing 2 to 30% by mass of a divinyl compound having a small molecular weight (both are 100% by mass in total), polymer fine particles capable of solving the problems of the present application are obtained. Among them, the average particle size is particularly 1 to 5 μm. And a fine polymer particle composition having a refractive index of 1.60 to 1.62 was found to be preferable.

  98-70 mass% is preferable, and, as for the compound of Chemical formula (1), 90-75 mass% is more preferable. If the amount is less than 70% by mass, fine particles having a refractive index of 1.60 or more cannot be obtained, and if it exceeds 98% by mass, it is difficult to make the average particle size of the polymer fine particles 5 μm or less.

2-30 mass% is preferable and, as for the divinyl compound of molecular weight smaller than the compound of Chemical formula (1), 10-25 mass% is more preferable. If it is less than 2% by mass, it will be difficult to make the average particle size of the polymer fine particles 5 μm or less, and if it exceeds 30% by mass, it will be difficult to obtain fine particles having a refractive index of 1.60 or more. .
As for this polymer fine particle composition, the following measuring method is mentioned, for example. The average particle diameter can be measured using a Beckman Coulter Multisizer 4 with an aperture hole diameter of 30 μm. The refractive index can be measured according to the JISK7132B method.
If a divinyl compound or a trivinyl compound having a molecular weight larger than that of the compound of the chemical formula (1) is used, the average particle diameter of the polymer fine particles obtained may be large, and the refractive index may be out of a predetermined range and the light diffusion effect may be inferior. is there.

The present inventors have found that divinyl compounds having a molecular weight smaller than the chemical formula (1) according to the present invention can be used in preparation of an O / W type emulsion and subsequent suspension polymerization in addition to the original function as a crosslinking agent. It is considered to have the effects i) to iv).
i) Excellent miscibility (affinity) with the chemical formula (1) and easily forms a uniform oil phase (oil droplets).
ii) In adjusting the O / W type emulsion, the effect of reducing the apparent viscosity of the oil phase mainly composed of the chemical formula (1) under shearing conditions is excellent.
iii) It is excellent in the rapidity of the crosslinking rate at the time of suspension polymerization reaction progress, and suppresses the increase in particles due to re-association between particles.
iv) Excellent copolymerization with the chemical formula (1).

  A preferred specific example of the divinyl compound in the present inventor is divinylbenzene (DVB, molecular weight 130) (obtained from the market) which has a sufficiently small molecular weight and is an aromatic compound similar to the compound of the chemical formula (1). Possible o-divinylbenzene, p-divinylbenzene mixture, ethylene glycol dimethacrylate (EDGMA. Molecular weight 198), 1,3-butanediol dimethacrylate (ED), which is a (meth) acrylic acid ester derivative as in chemical formula (1). BDDMA, molecular weight 226), hydroxy-3-acryloyloxypropyl methacrylate (alias: 1- (acryloyloxy) -3- (methacryloyloxy) -2-propanol) (HAPMA, molecular weight 214).

  The polymer fine particles according to the present invention can be obtained by a known suspension polymerization reaction apparatus and reaction step. A preferable production method is 98 to 70% by mass of chemical formula (1), 2 to 30% by mass of divinyl compound having a molecular weight smaller than that of ethoxylated o-phenylphenol acrylate (molecular weight 268) having a molecular weight smaller than chemical formula (1) (both combined) The oil phase and the aqueous phase comprising the O / W type emulsion, and the subsequent emulsion polymerization step of the O / W type emulsion.

  There is no restriction | limiting in the polymerization initiator used for suspension polymerization based on this invention. Usually, an oil-soluble peroxide polymerization initiator or an azo polymerization initiator used for aqueous suspension polymerization can be used. Specific examples include benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, o-chlorobenzoyl peroxide, o-methoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide, peroxide polymerization initiators such as t-butyl hydroperoxide and diisopropylbenzene hydroperoxide, azobisvaleronitrile, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4- Dimethylvaleronitrile), 2,2′-azobis (2,3-dimethylbutyronitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,3,3- Trimethylbutyronitrile), 2,2′-azobis (2 Isopropyl butyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), (2-carbamoylazo) isobutyro Examples include azo initiators such as nitrile, 4,4′-azobis (4-cyanovaleric acid), dimethyl-2,2′-azobisisobutyrate.

  Among these, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, lauroyl peroxide, etc. are suitable polymerization initiators. This is preferable in that it has a decomposition rate. The polymerization initiator is preferably used in an amount of 0.01 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the monomer mixture. When the polymerization initiator is less than 0.01 parts by mass, it is difficult to fulfill the function of initiating the polymerization, and when it is used in excess of 10 parts by mass, the addition amount is more than necessary, which is not preferable because it is not economical. .

  An oil / water mixture containing the compound of the chemical formula (1) and a divinyl compound having a lower molecular weight is dissolved in a polymerization initiator according to a conventional method and then stirred and mixed with an aqueous solution containing a polymerization stabilizer and a surfactant. Adjust to W-type emulsion. The O / W emulsion mixture is heated with stirring to conduct a polymerization reaction to obtain the desired polymer fine particle composition. As the polymerization stabilizer, a water-soluble polymer such as polyvinyl alcohol or an inorganic stabilizer such as calcium phosphate can be used.

  As the surfactant, a nonionic surfactant that does not affect the polymerization reactivity is used, and ester types such as glycerin fatty acid ester and sorbitan fatty acid ester, polyoxyethylene (or POE) alkyl ether, polyoxyethylene (or POE) Ether type such as alkylphenyl ether, polyoxyethylene polyoxypropylene glycol, etc., type with ethylene oxide added to fatty acid or polyhydric alcohol fatty acid ester, ester ether having both ester bond and ether bond in the molecule A mold or the like is used.

  After the suspension polymerization, the polymer fine particle composition particles are used after being subjected to a solid-liquid separation step and a drying step by a normal operation from the polymerization reaction solution and then taken out as a powder by pulverization. That is, after removing moisture by a method of drying a shelf after obtaining a wet cake by centrifugation, a method of spray drying, etc., and then applying impact with a hammer mill, a bead mill, etc. Can be obtained. The shape of the fine particles is not particularly limited, but a spherical shape, a spheroid and the like are preferable.

The polymer fine particle composition of the present invention can be prepared by a known method, for example, a light scattering sheet prepared by melting and kneading into a (meth) acrylic light diffusion sheet material, or a (meth) acrylic solution. It can be used in any of a method of forming by suspending, casting and removing the solvent, and a method of coating the surface of the sheet by suspending in a transparent epoxy prepolymer. At that time, various additives, fillers, and the like can be added. Further, the sheet surface can be subjected to an uneven pattern or embossing.
In addition, the thickness of these light diffusion sheets is not particularly limited, but is preferably 0.1 μm to 20 mm, more preferably 0.1 mm, from the viewpoints of application, productivity, handleability, and transportability. It is 5 micrometers-15 mm, More preferably, they are 1 micrometer-10 mm.
In addition to the above, the light diffusion sheet is made of a plastic material that is generally used, for example, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl alcohol (PVA), polyvinyl chloride (PVC). And resins such as polycarbonate (PC). For example, the polymer fine particle composition of the present invention can be used in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the resin for sheets.
For example, a compound obtained by kneading 100 parts of polyethylene terephthalate and 5 parts of the polymer fine particle composition of the present invention can be stretched to obtain a sheet having a thickness of 60 to 150 μm. Moreover, a stabilizer, an ultraviolet absorber, a lubricant, etc. can be added in the range which does not impair the transparency of these resins.

  The polymer fine particle composition of the present invention can be blended in paints, printing, inks, cosmetics and the like in addition to the light diffusion sheet.

  The fine polymer particle composition of the present invention can be used for paints. Examples thereof include organic solvent paints, water-based paints, emulsion paints, colloidal paints, and powder paints. 1-100 mass parts can be mix | blended with respect to 100 mass parts of coating resin parts. A compounding quantity becomes like this. Preferably it is 1-70 mass parts, More preferably, it is 1-20 mass parts.

  The polymer fine particle composition of the present invention can be used for printing ink. Examples thereof include letterpress ink, flat plate ink, intaglio ink, metal plate ink, radiation curable ink, UV ink, EB ink, flexographic ink, screen ink, offset ink, gravure ink, and water-based ink. 1-100 mass parts can be mix | blended with respect to 100 mass parts of resin solid content in an ink. A compounding quantity becomes like this. Preferably it is 1-70 mass parts, More preferably, it is 1-20 mass parts.

  The polymer fine particle composition of the present invention can be used in cosmetics. For example, makeup cosmetics, hair cosmetics, pack cosmetics and the like can be mentioned. For example, it can be used for gels, lipsticks, foundation blushers, mascaras, nail enamels, eyebrows, eye shadows, eyeliners, hair preparations and the like. As a compounding quantity, 1-90 mass parts is mentioned. For example, 1 to 50 parts by mass for the foundation, 1 to 80 parts by mass for the shadow, 1 to 40 parts by mass for the lipstick, and 0.1 to 20 parts by mass for the nail enamel are exemplified.

  The fine polymer particle composition of the present invention can be used by blending with a color toner for copying machines.

The present invention will be specifically described below with reference to examples, comparative examples, and test examples. In addition, a part is a mass part.
(Production method of polymer fine particle composition)

(Characteristic measurement method)
1) Average particle diameter The average particle diameter was measured using a Beckman Coulter Multisizer 4 and an aperture pore diameter of 30 μm. In Comparative Examples 9 to 14, since a large number of coarse particles having a particle diameter of 30 μm or more existed, an aperture hole diameter of 70 μm was used.
2) Refractive index The refractive index of fine particles was measured according to JIS K 7132 B method.

(Production of polymer fine particle composition)
(Examples 1-7)
In a dispersion container, 200 parts by mass of deionized water and 6 parts by mass of polyvinyl alcohol were added. Separately, as a compound of the chemical formula (1), a predetermined amount (see Table 1) of ethoxylated o-phenylphenol acrylate (EPPA, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “A-LEN-10”), chemical formula ( A predetermined divinyl compound having a molecular weight smaller than that of the compound 1), divinylbenzene (DVB, molecular weight 130), ethylene glycol dimethacrylate (EDGMA, molecular weight 198), 1,3-butanediol dimethacrylate (BDDMA, molecular weight 226), or hydroxy -3-acryloyloxypropyl methacrylate (alias: 1- (acryloyloxy) -3- (methacryloyloxy) -2-propanol) (HAPMA, molecular weight 214) in a predetermined amount (see Table 1), 100 parts by mass in total, And 1 part by weight of lauryl peroxide are adjusted to It added to the vessel, to an oil-water mixture. The obtained oil / water mixture was subjected to a dispersion treatment at 19000 rpm for 2 minutes by a disperser to obtain an O / W emulsion. This emulsion was poured into a polymerization reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet, and a polymerization reaction was carried out at 80 ° C. for 4 hours while introducing nitrogen.

(Comparative Examples 1-7)
Instead of the divinyl compound having a smaller molecular weight than the predetermined chemical formula (1) in the examples, trivinylpropane triacrylate (TMPTA, molecular weight 296), which is a trivinyl compound, 1, which is a divinyl compound having a higher molecular weight than the chemical formula (1), 10-decanediol diacrylate (DDDA, molecular weight 310), [2,2-bis (4- (methacryloxyethoxy) phenyl] propane (trade name “BPE-100” manufactured by Shin-Nakamura Chemical Co., Ltd.) The same process was performed.

  The results are shown in Table 1, and it is understood that a polymer fine particle composition having a refractive index of 1.60 to 1,62 and an average particle size of 2 to 5 μm is obtained only in the composition according to the present invention. . In particular, divinylbenzene as a divinyl compound stably gives a high refractive index regardless of mass%, and has a unique effect by combining a low molecular weight and a high affinity with the compound of the chemical formula (1). It can be seen that

(Manufacture of paint for light diffusion layer and light diffusion layer sheet)
60 parts of each fine particle and 200 parts of polyester resin Byron 20SS (Hot Melt Type manufactured by Toyobo Co., Ltd.) obtained in Examples and Comparative Examples were stirred and mixed at room temperature with a dispersion stirrer to obtain a “light diffusion layer coating material”.
As a base material, a PET sheet HSL-75 μm (made by Teijin DuPont) having a thickness of 75 μm is used. Was applied so that the dry film thickness was about 20 μm, and dried with hot air to obtain a dry coating film of the light diffusion layer. After the coating process, a heat aging treatment was performed for 48 hours in a constant temperature room at 40 ° C. to prepare a “light diffusion sheet”.

  The polymer fine particle composition according to the present invention has, for example, a high refractive index and an affinity with an acrylic resin, and is arranged in an uneven shape using a binder on the surface of the acrylic light diffusing sheet, or in the sheet Since it is possible to cause diffusion of transmitted light due to a difference in refractive index, it is suitably used as a light diffusing agent for a diffusion sheet for backlight.

Claims (7)

98 to 70% by mass of an ethoxylated o-phenylphenol (meth) acrylate compound represented by the chemical formula (1), 2 to 30% by mass of a divinyl compound having a molecular weight smaller than that of the chemical formula (1) (100% by mass in total) A polymer fine particle composition obtained by carrying out a copolymer reaction.

In the formula, R is H or —CH 3.   2. The fine polymer particle composition according to claim 1, wherein the average particle diameter is in the range of 2 to 5 [mu] m and the refractive index is in the range of 1.60 to 1.62.   The polymer fine particle composition according to claim 1 or 2, wherein the divinyl compound contains divinylbenzene.   A light scattering sheet comprising the polymer fine particle composition according to claim 1.   A light scattering agent comprising the polymer fine particle composition according to claim 1. 98 to 70% by mass of ethoxylated o-phenylphenol acrylate, 2 to 30% by mass of divinyl compound having a molecular weight smaller than that of ethoxylated o-phenylphenol (meth) acrylate (molecular weight 268 or 282) (both 100% by mass) A first step of emulsifying the oil phase and the aqueous phase comprising
A method for producing a polymer fine particle composition, comprising a second step of suspension polymerization of the O / W emulsion.   The method for producing a polymer fine particle composition according to claim 6, wherein the divinyl compound contains divinylbenzene.