JP2007297562A - Light-diffusible resin composition and light diffusion plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-diffusible resin composition being good in physical property, molding stability and handleability and a light diffusion plate produced from the composition. <P>SOLUTION: The light-diffusible resin composition comprises (A) a polyorganosiloxane-containing graft copolymer obtained by polymerizing (b) a 0 to 20 pts.wt. of a vinylic monomer that comprises (b-1) a 100 to 50 wt.% of a polyfunctional monomer containing 2 or more polymerizable unsaturated bonds and (b-2) 0 to 50 wt.% of another co-polymerizable monomer in the presence of (a) 30 to 95 pts.wt. of polyorganosiloxane in the form of latex with a volume average particle size ranging from 0.8 to 25 μm and then subjecting them to one or more steps of polymerization with (c) a 5 to 70 pts.wt. of vinylic monomer (provided that the total of (a), (b) and (c) is 100 pts.wt.) and (B) at least one type of transparent resin selected from the group consisting of a thermoplastic resin and a thermosetting resin. The light diffusion plate is obtained by the use of the composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light diffusing resin composition suitable for, for example, a light diffusing plate that can be used for a transmission screen for projection televisions, a light diffusing plate or lighting cover for liquid crystal backlights, a lighting signboard, and the like, and the composition. The present invention relates to a light diffusion plate to be obtained.

  In projection televisions, liquid crystal display devices, lighting covers, etc., in order to obtain light diffusibility, inorganic or organic fine particles having a refractive index different from that of the transparent resin are dispersed in a transparent resin. It has been widely used as a diffusible resin composition.

  For example, inorganic fine particles used in such applications include inorganic fine particles such as barium sulfate, calcium carbonate, and quartz, and organic fine particles include acrylic, styrene, and silicon resins having a crosslinked structure. Examples thereof include fine particles.

  However, generally, when the inorganic fine particles used conventionally and the organic fine particles having a crosslinked structure are blended with a transparent resin as a light diffusing agent, the impact strength of the light diffusing resin composition may be lowered. . For this reason, there existed a problem that it could be used only for the limited use.

  On the other hand, for the purpose of suppressing a decrease in physical strength of the matrix polymer when the fine particles are dispersed in the matrix polymer, the polymer fine particles are composed of a core / shell polymer, and the core is made of carbon. An acrylic system comprising a rubbery alkyl acrylate having 2 to 8 alkyl groups, the outer shell being miscible with the matrix polymer and present in the fine particles in an amount of about 5 to 40% by weight. (See, for example, Patent Documents 1 to 3). However, these acrylic polymer fine particles have a problem that heat resistance is inferior to conventional inorganic fine particles.

In order to solve the above problem, a light diffusing resin composition containing a 0.5 to 10 μm silicone resin having an organic functional group on the surface of a skeleton composed of a bifunctional siloxane unit and a trifunctional siloxane unit is disclosed ( Patent Document 4). However, this also has an organic functional group introduced on the surface, but the affinity with the transparent resin as a matrix is not sufficient, so the impact strength is low, and extrusion molding and molding by melting and kneading with the transparent resin Since the affinity in injection molding is low, there are problems that an unstable molded state and a heterogeneous molded product tend to be formed. In addition, since the volume average particle size is usually less than 10 μm and fine powder, the powder characteristics of the product are often inferior, which leads to inferior handling, intense dusting, worsening the working environment, or dust explosion. There were problems such as inviting.
JP-A 63-137911 Japanese Patent Laid-Open No. 2-311585 JP 7-238200 A JP-A-6-299035

  An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a light diffusing resin composition excellent in physical properties, molding stability, and handleability, and a light diffusion plate obtained from the composition. To do.

  As a result of repeated studies to provide a light diffusing resin composition excellent in impact resistance, heat resistance and molding stability, the present inventor has formulated a specific polyorganosiloxane-containing graft copolymer into a transparent resin. As a result, the inventors have found that the above-described problems can be solved, and have completed the present invention.

  That is, the present invention is a polyfunctional monomer containing two or more polymerizable unsaturated bonds in the presence of 30 to 95 parts by weight of a polyorganosiloxane (a) in a latex state having a volume average particle diameter of 0.8 to 25 μm. Polymerization of 0 to 20 parts by weight of a vinyl monomer (b) comprising 100 to 50% by weight of the body (b-1) and 0 to 50% by weight of another copolymerizable monomer (b-2); Furthermore, a polyorganosiloxane-containing graft obtained by polymerizing one or more stages of vinyl monomer (c) 5 to 70 parts by weight (however, the total of (a), (b) and (c) is 100 parts by weight). The present invention relates to a light diffusing resin composition comprising a copolymer (A) and at least one transparent resin (B) selected from the group consisting of a thermoplastic resin and a thermosetting resin.

  In a preferred embodiment, the polyorganosiloxane-containing graft copolymer (A) is a polyfunctional monomer containing two or more polymerizable unsaturated bonds in the presence of 30 to 95 parts by weight of the polyorganosiloxane (a). (B-1) polymerizing 100 to 50% by weight of vinyl monomer (b) consisting of 100 to 50% by weight and other copolymerizable monomer (b-2) 0 to 50% by weight; Further, it is obtained by polymerizing 4.5 to 69.5 parts by weight of the vinyl monomer (c) (however, the total of (a), (b) and (c) is 100 parts by weight) at least one stage. The present invention relates to the light diffusing resin composition.

  In a preferred embodiment, the polyorganosiloxane (a) is obtained by polymerizing a linear or branched siloxane having a terminal group selected from a hydroxyl group, an amino group and a hydrolyzable group. This relates to any one of the light diffusing resin compositions.

  A preferred embodiment relates to any one of the light diffusing resin compositions, wherein the polymerization of the vinyl monomer (b) and / or the vinyl monomer (c) is carried out by emulsion polymerization.

  In a preferred embodiment, the vinyl monomer (c) is a (meth) acrylic acid ester monomer, an aromatic vinyl monomer, a vinyl cyanide monomer, a carboxyl group-containing vinyl monomer. And one or two or more monofunctional monomers selected from vinyl chloride and vinyl chloride, and one or two or more polyfunctional monomers containing two or more polymerizable unsaturated bonds. The light diffusing resin composition according to any one of the above, wherein the light diffusing resin composition comprises ˜50 wt%.

  In a preferred embodiment, the light diffusion material according to any one of the above, wherein the polyorganosiloxane-containing graft copolymer (A) is contained in an amount of 0.01 to 500 parts by weight with respect to 100 parts by weight of the transparent resin (B). The present invention relates to a functional resin composition.

  A preferred embodiment relates to any one of the light diffusing resin compositions, wherein the transparent resin (B) has a total light transmittance of 50% or more of a molded product having a thickness of 2 mm.

  The present invention relates to a light diffusing plate obtained from any one of the light diffusing resin compositions.

  A preferred embodiment relates to the above light diffusing plate, characterized in that the total light transmittance is 10% or more and the haze is 40% or more.

  According to the present invention, a light diffusing resin composition excellent in impact resistance, heat resistance, and molding stability can be provided. This light diffusing resin composition can be suitably used for, for example, a transmissive screen for projection television, a light diffusing plate for liquid crystal backlight, or a light diffusing plate used for lighting covers, lighting signs, and the like.

  The present invention relates to a light diffusing resin composition containing a specific polyorganosiloxane-containing graft copolymer (A) and a transparent resin (B), and a light diffusing plate obtained from the resin composition.

  In the present invention, the polyorganosiloxane (a) that can be used in the production of the polyorganosiloxane-containing graft copolymer (A) is particularly a polyorganosiloxane having a volume average particle diameter of 0.8 to 25 μm. Without limitation, for example, it can be obtained by a known method of polymerizing cyclic, linear or branched organosiloxane using a catalyst such as acid, alkali, salt, fluorine compound and the like.

  Among these, from the viewpoint of controlling the volume average particle diameter of the polyorganosiloxane (a) within the target range, a linear or branched siloxane having a terminal group selected from a hydroxyl group, an amino group, and a hydrolyzable group is polymerized. It is preferable to obtain a latex of polyorganosiloxane (a). Based on the above, methods for obtaining a polyorganosiloxane (a) in a latex state are disclosed in, for example, JP-A Nos. 2001-288269 and 11-222554. On the other hand, it can also be obtained by ring-opening and condensation polymerization of cyclic organosiloxane, but cyclic organosiloxane tends to be difficult to maintain the particle size of oil droplets emulsified and dispersed during polymerization. May be difficult to control within a range of 0.8 to 25 μm. Therefore, the latex polyorganosiloxane (a) is more preferably obtained by polymerization using a linear or branched siloxane.

  The polyorganosiloxane (a) has, for example, a hydroxyl group, an amino group, or a hydrolyzable group at the end, and, if necessary, a mercaptopropyl group, a methacryloyloxypropyl group, an acryloyloxypropyl group, a vinyl group, or a vinylphenyl group. Group, a modified or non-modified linear or branched organosiloxane partially substituted with a radical reactive group such as an allyl group, if necessary, mixed with a known graft crossing agent or the like, water, It can be obtained by adding an emulsifier and the like, then forcibly emulsifying to a desired particle size by mechanical shearing, emulsifying and dispersing in water to make it acidic, and performing polymerization.

  As an apparatus for emulsifying and dispersing by mechanical shearing, any emulsifying and dispersing apparatus capable of adjusting the shear strength can be used without any particular limitation. As such an emulsifying and dispersing apparatus, for example, a known emulsifying and dispersing apparatus such as a homomixer, a centrifugal pump, a high-pressure homogenizer, or an ultrasonic dispersing apparatus can be suitably used.

  In the above method, since the particle diameter of the dispersed droplets during the emulsion dispersion substantially determines the average particle diameter of the polyorganosiloxane (a), the volume average particle diameter of the dispersed droplets of the emulsion is 0.8 to It is preferable to adjust the amount of siloxane, water and emulsifier used, and the strength of mechanical shear so as to be 25 μm.

  The linear or branched siloxane having a terminal group selected from a hydroxyl group, an amino group and a hydrolyzable group that can be used in the present invention has a volatile low molecular weight siloxane content of 5% by weight or less. More preferably, it is more preferably 1% by weight or less. In the linear or branched siloxane, when the content of the low molecular weight siloxane is large, the content of the low molecular weight siloxane after polymerization tends to increase. Furthermore, it is preferable to use the linear or branched siloxane having a weight average molecular weight of 500 to 100,000. When the weight average molecular weight of the siloxane is less than 500 or more than 100,000, it is difficult to stably obtain an emulsion having a volume average particle size of 0.8 to 25 μm by emulsification dispersion by mechanical shearing. Tend. Furthermore, the weight of the linear or branched siloxane can be obtained by using a homomixer, a centrifugal pump, or the like without using a high-pressure homogenizer or an ultrasonic dispersion device. The average molecular weight is more preferably 1,000 to 10,000, and still more preferably 2,000 to 6,000. Examples of the hydrolyzable group at the terminal of the linear or branched siloxane include an alkoxyl group, an acyloxy group, a ketoxime group, an alkenoxy group, an amide group, and an aminoxy group.

  In the polymerization of the polyorganosiloxane (a) that can be used in the present invention, a graft crossing agent such as a silane having a radical reactive group may be used if necessary, and a crosslinking agent may be used if necessary. it can.

  As the graft crossing agent, known ones can be used, but preferably a bifunctional vinyl polymerizable group-containing silane compound can be used. When a trifunctional or higher functional vinyl-based polymerizable group-containing silane compound is used, the impact resistance of the molded product obtained from the resin composition of the present invention may be lowered. The containing silane compound is more preferable. Specific examples of the graft crossing agent include γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, γ-acryloyloxypropyldimethoxymethylsilane, and 3-mercaptopropylmethyldimethoxysilane. It is done. These graft crossing agents can be used alone or in admixture of two or more. The proportion of the grafting agent used is preferably 0.1 to 10% by weight, more preferably 0.5 to 7% by weight, particularly preferably 1 to 5% by weight, based on the amount of polyorganosiloxane. If the amount of the grafting agent used exceeds 10% by weight, the impact resistance of the final molded product may be reduced. If the amount of the grafting agent used is less than 0.1% by weight, the light diffusibility of the molded product will be reduced. In addition, the formability of the final molded body may be reduced.

  In the production of the polyorganosiloxane (a) used in the present invention, a crosslinking agent can be used if necessary. Examples of the crosslinking agent include trifunctional crosslinking agents such as methyltrimethoxysilane, phenyltrimethoxysilane, and ethyltriethoxysilane, tetraethoxysilane, 1,3bis [2- (dimethoxymethylsilyl) ethyl] benzene, 1,4-bis [2- (dimethoxymethylsilyl) ethyl] benzene, 1,3-bis [1- (dimethoxymethylsilyl) ethyl] benzene, 1,4-bis [1- (dimethoxymethylsilyl) ethyl] benzene 1- [1- (dimethoxymethylsilyl) ethyl] -3- [2- (dimethoxymethylsilyl) ethyl] benzene, 1- [1- (dimethoxymethylsilyl) ethyl] -4- [2-dimethoxymethylsilyl] And tetrafunctional cross-linking agents such as ethyl] benzene. These crosslinking agents can be used singly or in combination of two or more. The amount of the crosslinking agent used is preferably 10% by weight or less, more preferably 3.0% by weight or less, based on the amount of polyorganosiloxane (a). When the amount of the crosslinking agent used exceeds 10% by weight, the flexibility of the polyorganosiloxane (a) is impaired, and the impact resistance of the final molded product may be lowered.

  In the polymerization of the polyorganosiloxane (a), when polymerizing under an acidic condition, it is preferable to use an emulsifier that does not lose the emulsification ability even under acidic conditions. Specific examples include alkylbenzene sulfonic acid, sodium alkylbenzene sulfonate, alkyl sulfonic acid, sodium alkyl sulfonate, sodium (di) alkyl sulfosuccinate, sodium polyoxyethylene nonylphenyl ether sulfonate, sodium alkyl sulfate, and the like. . These may be used alone or in combination of two or more. Among these, alkylbenzene sulfonic acid, sodium alkylbenzene sulfonate, alkyl sulfonic acid, sodium alkyl sulfonate, and sodium (di) alkyl sulfosuccinate are more preferable because of their relatively high emulsion stability. Furthermore, alkylbenzene sulfonic acid and alkyl sulfonic acid are preferable from the point of acting also as a polymerization catalyst for the polyorganosiloxane-forming component.

  In addition, polyoxyalkylene alkyl ether typified by polyoxyethylene dodecyl ether, polyoxyalkylene alkyl aryl ether typified by polyoxyethylene nonylphenyl ether, polyoxyalkylene higher fatty acid ester typified by polyoxyethylene stearate ester Nonionic emulsifiers such as sorbitan monolaurate can also be used. These can also be used in combination with the emulsifier.

  The acidic state can be adjusted by adding an inorganic acid such as sulfuric acid or hydrochloric acid, or an organic acid such as alkylbenzenesulfonic acid, alkylsulfonic acid, or trifluoroacetic acid to the system. The pH of the system is preferably adjusted to 1 to 3 and more preferably 1.0 to 2.5 from the viewpoint that the production facility is not corroded and an appropriate polymerization rate is obtained. The polymerization temperature is preferably 0 to 100 ° C. in that an appropriate polymerization rate can be obtained. In particular, when the polyorganosiloxane (a) is obtained by polymerizing a linear or branched siloxane having a terminal group selected from a hydroxyl group, an amino group and a hydrolyzable group, an appropriate polymerization rate is obtained. It is preferably 0 to 50 ° C., more preferably 15 to 30 ° C. from the viewpoint of reducing the amount of volatile siloxane obtained. When the polymerization temperature is lower than 0 ° C, the stability of the emulsion is reduced by freezing, and when it is higher than 50 ° C, volatile siloxane tends to increase.

  Since the polyorganosiloxane formation reaction under the acidic condition is an equilibrium reaction, after the polymerization under the acidic condition is completed, the polyorganosiloxane is made to have a high molecular weight by aging at room temperature for several hours or longer as necessary. Then, for example, an aqueous alkali solution such as sodium hydroxide, potassium hydroxide or sodium carbonate is added to neutralize the system so that the pH of the system is 5 to 8, thereby stopping the polymerization and stabilizing the siloxane chain. It is preferable.

  Similarly, when basic polymerization conditions are used in the production of polyorganosiloxane (a), it is preferable to use an emulsifier that is basic but capable of exhibiting surface activity. Examples of such emulsifiers include alkyltrimethylammonium salts such as dodecyltrimethylammonium bromide and stearyltrimethylammonium bromide, dialkyldimethylammonium salts such as didodecyldimethylammonium bromide, and alkylaralkylammonium salts such as stearyldimethylbenzylammonium chloride. Cationic emulsifiers can be mentioned. Nonionic emulsifiers as described above can also be used. These can also be used in combination with the cationic emulsifier.

  As a base for making basic conditions, inorganic bases, such as lithium hydroxide, potassium hydroxide, sodium hydroxide, cesium hydroxide, and organic bases, such as alkylammonium hydroxide, can be used, for example. For example, tetraorganammonium hydroxides such as cetyltrimethylammonium hydroxide described in JP-A-2001-106787 have both functions of a cationic emulsifier and a base. Therefore, it is preferably used. However, the present invention is not limited to this, and the base and the emulsifier may be either a single component or a combination of a plurality of components. After the polymerization is completed under basic conditions, aging is performed as necessary, and the system is neutralized with an inorganic acid such as sulfuric acid or an organic acid such as acetic acid or dodecylbenzenesulfonic acid in the same manner as described above. The polymerization can be stopped.

  The volume average particle diameter of the polyorganosiloxane (a) particles is preferably 0.8 to 25 μm, more preferably 1 to 20 μm, and particularly preferably 2 to 10 μm. When the volume average particle diameter of the polyorganosiloxane (a) is less than 0.8 μm, the light reflecting surface relatively increases with the relative increase in particle surface area, so that the light transmittance of the light diffusing plate is increased. Tends to be low. On the other hand, when the volume average particle diameter of the polyorganosiloxane (a) exceeds 25 μm, the polymerization may become unstable such as generation of scale when the polyorganosiloxane (a) is produced, and the light diffusion performance. And the impact strength of the resulting molded product tends to decrease. Furthermore, the surface appearance of the light diffusing plate may be deteriorated. The volume average particle diameter of the polyorganosiloxane (a) can be measured using, for example, a Microtrac particle size analyzer Model 9220FRA (manufactured by Nikkiso Co., Ltd.).

  The vinyl monomer (c) used in the production of the polyorganosiloxane-containing graft copolymer (A) of the present invention is a transparent resin (B) that becomes a matrix resin with the polyorganosiloxane copolymer (A) of the present invention. ) Is a component that can be used to ensure compatibility. The vinyl monomer (c) may be polymerized in one stage or in two or more stages. The vinyl monomer (c) may be a single compound or a mixture of two or more compounds.

  Specific examples of the monomer that can be used as the vinyl monomer (c) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid. (Meth) acrylic acid alkyl ester monomers such as butyl, (meth) acrylic acid n-octyl, (meth) acrylic acid 2-ethylhexyl, styrene, α-methylstyrene, chlorostyrene, chloromethyl Aromatic vinyl monomers such as styrene, vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile, and (meth) acrylic acid Carboxyl group-containing vinyl monomers, vinyl acetate, monofunctional monomers such as vinyl chloride, or (meth) acrylic Represented by allyl acid, diallyl phthalate, ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, diallyl itaconate, divinylbenzene, triallyl cyanurate, triallyl isocyanurate, etc. Examples thereof include polyfunctional monomers having two or more polymerizable unsaturated groups in the molecule, and mixtures thereof. In the present invention, unless otherwise specified, for example, (meth) acryl means acryl and / or methacryl.

  Among them, from the viewpoint of the affinity between the polyorganosiloxane-containing graft copolymer (A) of the present invention and the transparent resin (B) serving as a matrix, as the vinyl monomer (c), a (meth) acrylic acid ester One or two or more monofunctional monomers selected from monomers, aromatic vinyl monomers, vinyl cyanide monomers, carboxyl group-containing vinyl monomers, and vinyl chloride It is preferably composed of 100% by weight and 0 to 50% by weight of one or more polyfunctional monomers containing two or more polymerizable unsaturated bonds. Furthermore, it is more preferable that the vinyl monomer (c) is composed of the monofunctional monomer and does not contain the polyfunctional monomer.

  In the polymerization of the vinyl monomer (c), a known chain transfer agent can be used in combination as appropriate. Specific examples of the chain transfer agent include unsaturated terpenes such as α-pinene, terpinolene and limonene, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, 2-ethylhexyl thioglycolate and the like. Examples of the mercaptans can be exemplified. Among these, the mercaptans can be preferably used. Furthermore, 2-ethylhexyl thioglycolate can be most preferably used because a polyorganosiloxane-containing graft copolymer or resin composition having no odor can be obtained.

  The amount of the chain transfer agent used relative to the vinyl monomer (c) is preferably 10% by weight or less, more preferably 5% by weight or less, and further 2% by weight or less. When the chain transfer agent is used in excess of 10% by weight, the graft efficiency of the polymer produced from the vinyl monomer (c) tends to be reduced.

  The polymerization of the vinyl monomer (c) is preferably carried out by an emulsion polymerization method. When the emulsion polymerization method is employed, a known polymerization initiator, that is, 2,2′-azobisisobutyronitrile, hydrogen peroxide, potassium persulfate, ammonium persulfate, or the like is used as a thermal decomposition type polymerization initiator. Can do. In addition, organic peroxides such as t-butylperoxyisopropyl carbonate, paramentane hydroperoxide, cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-hexyl peroxide, etc. Oxides; peroxides such as inorganic peroxides such as hydrogen peroxide, potassium persulfate, and ammonium persulfate; reducing agents such as sodium formaldehyde sulfoxylate and glucose as necessary; and iron sulfate (II as necessary) ) And the like, and if necessary, a chelating agent such as disodium ethylenediaminetetraacetate, and if necessary, a redox type polymerization initiator using a phosphorus-containing compound such as sodium pyrophosphate. .

  When a redox type polymerization initiator system is used, the polymerization can be carried out even at a low temperature at which the peroxide is not substantially thermally decomposed, so that the polymerization temperature can be set in a wide range, which is preferable. Among them, it is preferable to use an aromatic ring-containing peroxide such as cumene hydroperoxide and dicumyl peroxide as a redox type polymerization initiator. The amount of the polymerization initiator used and the amount of the reducing agent / transition metal salt / chelating agent used in the case of using a redox type polymerization initiator can be used within a known range.

  Further, during the emulsion polymerization, an emulsifier can be additionally added as necessary, but this can also be used within a known range.

  Various conditions such as polymerization temperature, pressure, deoxygenation and the like in the emulsion polymerization can be applied within known ranges. The polymerization of the vinyl monomer (c) may be performed in one stage or in two or more stages. A method of adding the vinyl monomer (c) at once to an emulsion obtained by polymerizing a polyorganosiloxane (a) or a vinyl monomer (b) described later in the presence of the polyorganosiloxane (a). In the presence of polyorganosiloxane (a) or polyorganosiloxane (a), a vinyl system described later is added to a reactor in which a monomer containing vinyl monomer (c) is charged in advance or in a continuous addition method. A method of performing polymerization after adding an emulsion obtained by polymerizing the monomer (b) can be appropriately employed.

  In the production of the polyorganosiloxane-containing graft copolymer (A) of the present invention, in the presence of the latex polyorganosiloxane (a), a polyfunctionality containing two or more polymerizable unsaturated bonds as necessary. A vinyl monomer (b) comprising 100 to 50% by weight of the monomer (b-1) and 0 to 50% by weight of another copolymerizable monomer (b-2) is polymerized; The vinyl monomer (c) can be polymerized.

  The vinyl monomer (b) that can be used for the production of the polyorganosiloxane-containing graft copolymer (A) of the present invention is a polyfunctional monomer containing two or more polymerizable unsaturated bonds in the molecule. (B-1) and other copolymerizable monomer (b-2), the polyfunctional monomer (b-1) is preferably 100 to 50% by weight, More preferably, it is 100 to 80% by weight. On the other hand, the other copolymerizable monomer (b-2) is preferably 0 to 50% by weight, and more preferably 0 to 20% by weight.

  Specific examples of the polyfunctional monomer (b-1) include allyl (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, ethylene glycol di (meth) acrylate, and di (meth). Examples thereof include 1,3-butylene glycol acrylate, diallyl itaconate, and divinylbenzene. These may be used alone or in combination of two or more. Among these, the use of allyl (meth) acrylate and triallyl cyanurate is particularly preferred from the viewpoint of economy and effects.

  Specific examples of the other copolymerizable monomer (b-2) include, for example, aromatic vinyl monomers such as styrene, α-methylstyrene, paramethylstyrene, and parabutylstyrene, acrylonitrile, and methacrylate. Vinyl cyanide monomers such as nitrile, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, hydroxyethyl acrylate, hydroxybutyl acrylate, methacryl (Meth) acrylic acid ester monomers such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, lauryl methacrylate, glycidyl methacrylate, hydroxyethyl methacrylate, itaconic acid, (meth) acrylic acid, fumaric acid, maleic acid Carboxyl group-containing Such as Le monomer and the like. These may be used alone or in combination of two or more.

  In the production of the polyorganosiloxane-containing graft copolymer (A) of the present invention, when the vinyl monomer (b) containing the polyfunctional monomer (b-1) as a main component is used, the vinyl It is considered that the grafting efficiency to the polyorganosiloxane (a) when polymerizing the monomer (c) can be increased, and the compatibility with the transparent resin (B) serving as a matrix is increased. Thereby, there exists a tendency for shaping | molding stability, the light diffusibility of a final molded object, and impact resistance to improve. The polymerization of the vinyl monomer (b) is preferably carried out by an emulsion polymerization method as in the vinyl monomer (c).

  The polyorganosiloxane-containing graft copolymer (A) according to the present invention contains 0 to 20 parts by weight of the vinyl monomer (b) in the presence of 30 to 95 parts by weight of the polyorganosiloxane (a). Polymerized and further obtained by polymerizing the vinyl monomer (c) 5 to 70 parts by weight (however, the total of (a), (b) and (c) is 100 parts by weight) Furthermore, in the presence of 30 to 95 parts by weight of the polyorganosiloxane (a), 0.5 to 10 parts by weight of the vinyl monomer (b) is polymerized, and further the vinyl monomer (c). What is obtained by superposing | polymerizing 4.5-69.5 weight part (however, the sum total of (a), (b), (c) is 100 weight part) is more preferable.

  The amount of the polyorganosiloxane (a) in 100 parts by weight of the polyorganosiloxane-containing graft copolymer (A) is preferably 30 to 95 parts by weight, and more preferably 50 to 90 parts by weight. When the amount of polyorganosiloxane (a) is less than 30 parts by weight, the content of polyorganosiloxane (a) is too low to make it difficult to develop impact resistance and heat resistance derived from polyorganosiloxane. There is. On the contrary, when the polyorganosiloxane (a) is more than 95 parts by weight, the affinity between the polyorganosiloxane-containing graft copolymer (A) and the transparent resin (B) serving as a matrix is not sufficient, and these are melted. In extrusion molding and injection molding in which kneading is performed, an unstable molded state and a non-homogeneous molded product are likely to be obtained, and the surface appearance of the light diffusing plate may be deteriorated.

  The amount of the vinyl monomer (c) in 100 parts by weight of the polyorganosiloxane-containing graft copolymer (A) is preferably 5 to 70 parts by weight, and more preferably 10 to 50 parts by weight. When the amount of the vinyl monomer (c) is more than 70 parts by weight, the content of the polyorganosiloxane (a) is relatively lowered, so that the impact resistance and heat resistance derived from the polyorganosiloxane are expressed. It may be difficult. On the contrary, when the amount of the vinyl monomer (c) is less than 5 parts by weight, the affinity between the polyorganosiloxane-containing graft copolymer (A) and the transparent resin (B) as a matrix is not sufficient, In extrusion molding or injection molding in which these are melt kneaded and molded, an unstable molded state and a non-homogeneous molded product tend to be formed, and the surface appearance of the light diffusing plate may be deteriorated.

  The amount of the vinyl monomer (b) in 100 parts by weight of the polyorganosiloxane-containing graft copolymer (A) is preferably 0 to 20 parts by weight, more preferably 0.5 to 10 parts by weight. 5% by weight is particularly preferred. When the amount of the vinyl monomer (b) is more than 20 parts by weight, the impact resistance of the final molded product may be lowered.

  Thus, when the polyorganosiloxane-containing graft copolymer (A) of the present invention is obtained by emulsion polymerization, a divalent or higher metal salt such as calcium chloride, magnesium chloride, magnesium sulfate or aluminum chloride is added to the latex. After the latex is coagulated by addition, the graft copolymer (A) can be separated from the aqueous medium by heat treatment, dehydration, washing and drying according to a known method (coagulation method). As the above-mentioned divalent or higher metal salt, calcium chloride and magnesium chloride are preferable because they are particularly economically available at low cost and are easy to handle. Furthermore, when it is desired not to contain a trace amount of halogen for environmental considerations, magnesium sulfate can be suitably used. In the step after the salt coagulation, the slurry is preferably diluted 20 times, more preferably 30 times, and even 50 times or more before dehydration, or the solid content of the graft copolymer (A) in the step after dehydration. Is preferably 3 times, more preferably 5 times, and even 10 times or more of solvent, preferably by spraying water from the viewpoint of environmental impact and washing, thereby burning or decomposing during molding of the transparent resin (B) Problems can be reduced.

  Alternatively, the graft copolymer (A) is precipitated by adding a water-soluble organic solvent such as methanol, ethanol, propanol or the like or acetone to the latex, and is separated from the solvent by centrifugal dehydration or filtration, and then dried. And can be isolated. As another method, an organic solvent having some water solubility such as methyl ethyl ketone is added to the latex containing the graft copolymer (A) of the present invention to extract the copolymer (A) in the latex into the organic solvent layer, Examples include a method in which the organic solvent layer is separated and then mixed with water to precipitate a copolymer component.

  The latex can also be directly powdered by spray drying. In this case, the same effect can be obtained by washing the obtained powder of the graft copolymer (A) with a solvent in the same manner as in the coagulation method described above.

  When using the powdery resin as the transparent resin (B) according to the present invention, the graft copolymer (A) of the present invention preferably has a volume average particle size of 1 μm or more, more preferably 10 μm or more, Is preferably recovered as a powder of 50 μm or more, preferably 1 mm or less, more preferably 500 μm or less, and even 200 μm or less. In particular, it is preferable that the average particle diameter of the transparent resin (B) powder is close to or similar to the volume average particle diameter because classification becomes difficult. As the powder of the graft copolymer (A), the graft copolymer (A) of the present invention is in a state of being gently agglomerated so that the graft copolymer (A) in the transparent resin (B) can be obtained. ) From the viewpoint of easy dispersion of primary particles.

  The polyorganosiloxane-containing graft copolymer (A) of the present invention is mixed with the transparent resin (B) and subjected to molding, coating, etc., so that the particle unit size of the polyorganosiloxane-containing graft copolymer is increased. Can be dispersed. Further, the obtained light diffusing resin composition can be suitably used for, for example, a transmissive screen for projection television, a light diffusing plate for liquid crystal backlight, or a light diffusing plate used for lighting covers, lighting signs, etc. .

  As the transparent resin (B) in the present invention, at least one selected from the group consisting of known thermoplastic resins and thermosetting resins can be used.

  As a preferable thermoplastic resin that can be used as the transparent resin (B) serving as the matrix resin, polycarbonate resin such as aromatic polycarbonate and aliphatic polycarbonate, polyester resin, polyvinyl acetal resin, aromatic alkenyl compound, methacrylic acid ester, A vinyl polymer or copolymer resin obtained by polymerizing or copolymerizing one or more vinyl monomers selected from the group consisting of acrylic acid esters and vinyl cyanide compounds, transparent polyolefin such as polypropylene, and vinyl chloride Examples thereof include transparent cellulose resins such as resins and acetylcellulose. These can be used alone or in a blend of two or more.

  Examples of the vinyl chloride resin that can be used in the present invention include a vinyl chloride homopolymer, or a copolymer of vinyl chloride with another vinyl monomer having at least one double bond that can be copolymerized with vinyl chloride. A chlorinated vinyl chloride resin and a chlorinated polyethylene resin can be exemplified, and the other vinyl monomer in the copolymer is preferably 50% by weight or less, more preferably 45% by weight or less. Examples of other vinyl monomers having at least one double bond include, for example, ethylene, propylene, vinyl acetate, (meth) acrylic acid and its ester, maleic acid and its ester, vinylidene chloride, vinyl bromide And acrylonitrile. These vinyl chloride resins can be obtained by homopolymerizing or copolymerizing vinyl chloride alone or vinyl chloride and the other vinyl monomer in the presence of a radical polymerization initiator, for example. The degree of polymerization of the vinyl chloride resin is usually 400 to 4500, and particularly preferably 400 to 1500.

  A vinyl polymer or copolymer obtained by polymerizing or copolymerizing at least one vinyl monomer selected from aromatic alkenyl compounds, methacrylic acid esters, acrylic acid esters and vinyl cyanide compounds that can be used in the present invention. The polymer resin may be copolymerized with a diene monomer, an olefin monomer, a maleimide monomer, or the like, and may be further hydrogenated. Examples of the vinyl polymer or copolymer resin include polystyrene resin, s-polystyrene resin, polymethyl methacrylate resin, polychlorostyrene resin, polybromostyrene resin, poly α-methylstyrene resin, and styrene-acrylonitrile copolymer. Polymer resin, styrene-methyl methacrylate copolymer resin, acrylonitrile-styrene-methyl methacrylate copolymer resin, styrene-maleic anhydride copolymer resin, styrene-maleimide copolymer resin, styrene-N-phenylmaleimide copolymer Resin, styrene-N-phenylmaleimide-acrylonitrile copolymer resin, methyl methacrylate-butyl acrylate copolymer resin, methyl methacrylate-ethyl acrylate copolymer resin, styrene-acrylonitrile α-methylstyrene terpolymer resin, acrylonitrile-butadiene rubber-styrene copolymer (ABS) resin, acrylonitrile-butadiene rubber-α-methylstyrene copolymer resin, aromatic alkenyl compound-diene-vinyl cyanide- Examples thereof include N-phenylmaleimide copolymer resin.

  Polyester resins that can be used in the present invention include those obtained by polycondensation products of dicarboxylic acids or derivatives of dicarboxylic acids such as alkyl esters with diols, or alkyls of carboxylic acids or carboxylic acids in one molecule. Examples include those obtained by polycondensation of a derivative having both a derivative such as an ester and a hydroxyl group, and ring-opening polymerization of a monomer having a cyclic ester structure in one molecule.

  Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, adipic acid, sebacic acid, and the like. Examples of the diol include ethanediol, propanediol, butanediol, pentanediol, hexanediol, and the like. Examples of the monomer having both a carboxylic acid or a derivative such as an alkyl ester of a carboxylic acid and a hydroxyl group in one molecule include hydroxyalkanoic acids such as lactic acid and hydroxypropionic acid. Examples of the monomer having a cyclic ester structure in one molecule include caprolactone.

  Specific examples of the polyester resin include polymethylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polytetramethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene naphthalate, polylactic acid, polyhydroxybutyric acid, butylene polysuccinate, poly-ε -Caprolactone, poly (α-oxyacid) and copolymers thereof, and blends thereof can be exemplified, but in the present invention, polybutylene terephthalate, polyethylene terephthalate, and polylactic acid are particularly preferable.

  The polyvinyl acetal resin that can be used in the present invention is obtained by modifying polyvinyl alcohol with aldehydes, and examples thereof include polyvinyl formal and polyvinyl butyral.

  The transparent polyolefin resin that can be used in the present invention includes not only a polymer composed only of olefins typified by polypropylene, polymethylpentene, polybutene, cycloolefin polymer or copolymer, but also olefin and copolymerizable double resin. Also included are copolymers with compounds having at least one bond, such as ethylene-vinyl acetate copolymers. Examples of the compound having copolymerizability with the olefin include (meth) acrylic acid and its ester, maleic acid and its ester, maleic anhydride, vinyl acetate and the like.

  The polycarbonate resin that can be used in the present invention is obtained by reacting a dihydric phenol with phosgene or a carbonate precursor. As the dihydric phenol, bis (hydroxyaryl) alkane is preferable, for example, bis (hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,2-bis (4-hydroxyphenyl) ethane, 2 , 2-bis (hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2 -Bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (hydroxyphenyl) hexafluoropropane and the like. Other dihydric phenols include 1,1-bis (4-hydroxyphenyl) cyclohexane; 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane; 1,1-bis (4- Bis (4-hydroxyphenyl) cycloalkane such as hydroxyphenyl) cyclodecane, 1,1-bis (4-hydroxyphenyl) fluorene; 1,1-biscresol fluorene; fluorene derivatives such as 1,1-bisphenoxyethanol fluorene, phenyl Bis (hydroxyphenyl) methane; Diphenylbis (hydroxyphenyl) methane; Phenyl group-containing bis (hydroxyphenyl) alkane such as 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane, 4,4′-dihydroxydiphenyl Bis (4-hydroxy Phenyl) oxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) ketone, hydroquinone, piperazine, dipiperidylhydroquinone, resorcin, etc. Is mentioned. These dihydric phenols can be used alone or in combination. Of these, dihydric phenol containing no halogen can be preferably used. Particularly preferred dihydric phenols are bis (hydroxyphenyl) methane, 2,2'-bis (hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) fluorene. Examples of the carbonate precursor include diaryl carbonates such as diphenyl carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate. In addition to these aromatic polycarbonate resins, aliphatic polycarbonate resins such as polyethylene carbonate can also be used. These polycarbonate resins may be those in which dimethylsiloxane is copolymerized in the main chain.

  Preferred thermosetting resins that can be used as the transparent resin (B) include epoxy resins, polyamideimide resins, thermosetting polyester resins (unsaturated polyester resins), silicone resins, urethane resins, and (meth) acrylic resins. And fluorine-based resin.

  Examples of the epoxy resin that can be used in the present invention include novolak resins obtained by condensing phenols, biphenols, or naphthols with aldehydes, such as phenol novolac type epoxy resins and cresol novolak type epoxy resins. Novolac type epoxy resin, biphenyl type epoxy resin such as 2,2 ′, 6,6′-tetramethylbiphenol diglycidyl ether, biphenol or aromatic nucleus substituted biphenols or bisphenol A, F, S, trimethylolpropane There are a wide range of commonly used epoxy resins such as polyglycidyl ethers of polyhydric phenols or polyhydric alcohols or condensates thereof, or alicyclic epoxy resins containing a cycloolefin oxide structure skeleton in one molecule. Ku is available.

  Among these, diglycidyl ether of biphenol or aromatic nucleus-substituted biphenol or its condensate, novolac type epoxy resin, dicyclopentadienyl type epoxy resin, alicyclic epoxy containing cycloolefin oxide structure skeleton in one molecule It is preferable to contain at least 50% by weight of one or more epoxy resins selected from resins with respect to the total amount of the thermosetting resin. These can be cured using phenol resins such as phenol novolac, aliphatic amines, aromatic amines, or carboxylic acid derivatives such as acid anhydrides and blocked carboxylic acids. Among these, it is particularly preferable to use a phenol resin from the viewpoint that the heat resistance of the resulting cured product is increased.

  Among the resins exemplified as the transparent resin (B), (meth) acrylic such as polycarbonate resin, polymethyl methacrylate resin, methyl methacrylate-butyl acrylate copolymer resin, etc. from the viewpoint of excellent light transmittance. More preferred are resins, styrene resins such as polystyrene, methyl methacrylate-styrene copolymer resins, styrene-acrylonitrile copolymer resins, acrylonitrile-butadiene rubber-styrene copolymer (ABS) resins, and vinyl chloride resins. The said transparent resin (B) can be used individually or in combination. However, when a plurality of resins are used in combination, the total light transmittance is often lowered, so that it is preferable to use them alone.

  The transparent resin (B) in the present invention is not particularly limited as long as it is a known resin having transparency, but the light diffusion plate obtained from the light diffusing resin composition according to the present invention exhibits excellent light diffusion performance. From the standpoint of possible, it is preferable that the total light transmittance of the 2 mm-thick molded product made of the transparent resin (B) is 50% or more, more preferably 60% or more, particularly 80% or more. More preferred. For example, the 2 mm-thick molded body can be obtained according to a known method such as a press molding method, an injection molding method, or an extrusion molding method. For example, the total light transmittance can be measured for a molded product obtained by an injection molding method by using a commercially available light transmittance measuring device.

  The light diffusing plate obtained from the light diffusing resin composition of the present invention is, for example, a monomer, a monomer mixture, or a mixture of a polymer and a monomer (syrup) used in the production of the transparent resin (B). ) Etc., the polyorganosiloxane-containing graft copolymer (A) is mixed and dispersed in a casting polymerization method in which it is polymerized in the mold, and the polyorganosiloxane-containing graft copolymer (A) is mixed and dispersed in the transparent resin (B). Then, the resulting mixture is pelletized using an extruder or the like, extruded or injection molded, or the transparent resin (B) in which the polyorganosiloxane-containing graft copolymer (A) is dispersed is formed into a flat or It can be produced by a method in which it is uniformly applied to one or both of the film-like resins.

  The blending amount of the polyorganosiloxane-containing graft copolymer (A) with respect to the transparent resin (B) is different from the characteristics required for the light diffusing plate depending on the use of the light diffusing plate. The polyorganosiloxane-containing graft copolymer (A) is blended in an amount of 0.01 to 500 parts by weight, preferably 0.05 to 300 parts by weight with respect to 100 parts by weight of the resin (B).

  The optimum blending amount of the polyorganosiloxane-containing graft copolymer (A) is the characteristics of the transparent resin (B) (total light transmittance, refractive index, etc.) and the characteristics of the polyorganosiloxane-containing graft copolymer (A) ( The total light transmittance, refractive index, average particle diameter, etc.) can be determined. For example, when the difference in refractive index between the polyorganosiloxane-containing graft copolymer (A) and the transparent resin (B) is small, the polyorganosiloxane-containing graft copolymer (A) is added to the transparent resin (B). If a large amount is not blended, good light diffusibility cannot be obtained, and if the average particle diameter of the polyorganosiloxane-containing graft copolymer (A) is relatively small, the polyresin is in proportion to the transparent resin (B). Unless the blending amount of the organosiloxane-containing graft copolymer (A) is reduced, it is difficult to obtain good light transmittance. On the contrary, when the difference in refractive index between the polyorganosiloxane-containing graft copolymer (A) and the transparent resin (B) is large, the polyorganosiloxane-containing graft copolymer (A) with respect to the transparent resin (B). If the blending amount of is not reduced, it is difficult to obtain good light transmittance, and when the average particle size of the polyorganosiloxane-containing graft copolymer (A) is relatively large, the transparent resin (B) If the amount of the polyorganosiloxane-containing graft copolymer (A) is excessive, good smoothness of the light diffusing plate surface cannot be obtained, and the coating of the light diffusing resin composition becomes difficult. May happen.

  The light diffusing plate produced using the light diffusing resin composition of the present invention has good light transmittance and light diffusing property. Light diffusion plate thickness, average particle diameter of polyorganosiloxane (a), difference in refractive index between polyorganosiloxane-containing graft copolymer (A) and transparent resin (B), polyorganosiloxane content in light diffusion plate Although it varies depending on the content of the graft copolymer (A), the light transmittance (total light transmittance) of the light diffusion plate having a thickness of 2 mm is 10% or more, preferably 20% or more, more preferably 40% or more. The light diffusibility (also referred to as haze) is 40% or more, preferably 50% or more, more preferably 90% or more. The light transmittance and light diffusibility can be measured by using, for example, an integrating sphere type light transmittance measuring device (NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.).

  In the light diffusing resin composition of the present invention, if necessary, for example, a plasticizer, a curing agent, a dispersant, various leveling agents, an ultraviolet absorber, a viscosity modifier, a lubricant, and a deterioration preventive agent. Agents, antistatic agents, flame retardants, fluorescent brighteners, fluorescent dyes, pigments, colorants, antioxidants (eg sulfur-containing molecules, phosphites, hindered phenols, hypophosphites, phosphonites) and light stabilization Stabilizers such as agents (such as UV stabilizers), tackifiers, mold release agents, impact modifiers, processing aids, fillers (eg, glass fibers), heat resistance imparters, etc. The additive mix | blended with a board can be used suitably.

  The transparent resin (B) and the polyorganosiloxane-containing graft copolymer (A) constituting the light diffusing resin composition of the present invention can be used in any combination as long as the characteristics of the light diffusing plate are not impaired. May be.

  This light diffusing resin composition can be widely used in applications requiring light diffusibility, such as a transmissive screen for projection television, a light diffusing plate for liquid crystal backlight, or a lighting cover or lighting signboard.

  Next, although a specific Example is given and demonstrated, these are all illustrations and do not limit the content of the present invention at all.

  The volume average particle size was measured with a Microtrac particle size analyzer Model 9220FRA (manufactured by Nikkiso Co., Ltd.).

  The light transmittance was evaluated by measuring the total light transmittance using an integrating sphere type light transmittance measuring device (NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K7361-1.

  Light diffusivity was evaluated by measuring haze using an integrating sphere light transmittance measuring device (NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K7136.

  The Izod strength was measured in accordance with JIS K7110 using a No. 2 test piece (A notch, width b = 6.4 ± 0.3 mm) at a temperature of 23 ° C. and a relative humidity of 50%.

The appearance of the molded body was determined by the size of the rough surface portion generated at the gate portion of the light diffusion plate molded body. The surface roughness less than an area 0.5 cm ² ○ (excellent), a surface roughness area 0.5 to 1 cm ² △ (parallel), the surface roughness area 1 cm ² or more was × (poor).

  The powder characteristics were evaluated based on the handleability during work. That is, when handling a light diffusable resin composition, it was set as (circle) (excellent) when there was almost no powdering, and x (inferior) when intense.

(Production Example 1)
100 parts by weight of water, 0.5 part by weight of sodium dodecylbenzenesulfonate, 1 part by weight of dodecylbenzenesulfonate, 100 parts by weight of terminal hydroxyorganopolysiloxane (trade name: PRX413, manufactured by Toray Dow Corning Silicone Co., Ltd.), γ- A mixed solution consisting of 3 parts by weight of methacryloyloxypropylmethyldimethoxysilane (hereinafter also referred to as DSMA) K. A mechanical shear was applied by ROBOMIX at a rotation speed of 10,000 rpm for 5 minutes to prepare an O / W type siloxane emulsion. The siloxane emulsion was quickly charged all at once into a flask equipped with a stirrer, reflux condenser, nitrogen blowing port, monomer addition port, and thermometer. 150 parts by weight of water was added, and the mixture was reacted at 25 ° C. for 24 hours while stirring the system. Thereafter, the pH of the system was adjusted to 6.8 with sodium hydroxide to complete the polymerization, and latex (SR) containing polyorganosiloxane polymer particles having a volume average particle diameter of 6.1 μm was obtained.

  Subsequently, the latex was diluted with pure water to a solid content concentration of 15% by weight, and then 4 parts by weight (solid content) of 2.5% by weight calcium chloride aqueous solution was added to obtain a coagulated slurry. The coagulated slurry was heated to 100 ° C., cooled to 50 ° C., dehydrated, and dried to obtain a polyorganosiloxane powder (SR-1) having a volume average particle size of 60 μm.

(Production Example 2)
70 parts by weight (solid content) of the polyorganosiloxane particle latex (SR) obtained in Production Example 1 was charged into a 5-neck flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer. The temperature was raised to 60 ° C. under a nitrogen stream while stirring. After reaching 60 ° C., sodium formaldehyde sulfoxylate (hereinafter also referred to as SFS) 0.39 parts by weight, ethylenediaminetetraacetic acid disodium (hereinafter also referred to as EDTA) 0.004 parts by weight, ferrous sulfate 0.001 After adding parts by weight, 1.5 parts by weight of allyl methacrylate (hereinafter also referred to as ALMA) and 0.04 parts by weight of cumene hydroperoxide were mixed and then added all at once, and stirring was continued at 60 ° C. for 1 hour. It was. After that, 28.5 parts by weight of methyl methacrylate (hereinafter also referred to as MMA) and 0.23 part by weight of cumene hydroperoxide were mixed and then continuously added dropwise over 1.5 hours. Stirring was continued for a time to obtain a graft copolymer latex.

  Subsequently, the latex was diluted with pure water to a solid content concentration of 15% by weight, and then 4 parts by weight (solid content) of 2.5% by weight calcium chloride aqueous solution was added to obtain a coagulated slurry. The coagulated slurry was heated to 100 ° C., cooled to 50 ° C., dehydrated, and dried to obtain a polyorganosiloxane-containing graft copolymer powder (SG-1) having a volume average particle size of 110 μm.

(Production Example 3)
In Production Example 2, a polyorganosiloxane-containing graft having a volume average particle size of 130 μm was used except that allyl methacrylate was not polymerized and methyl methacrylate (MMA) was changed to 30 parts by weight. A copolymer powder (SG-2) was obtained.

(Examples 1 and 2)
Polyorganosiloxane-containing graft obtained in Production Example 2 with respect to 100 parts by weight of polycarbonate resin (manufactured by Teijin Chemicals Ltd., Panlite L-1225WX, total light transmittance 90.1% of 2 mm-thick molded product) Copolymer powder (SG-1) was blended in the number of parts (parts by weight) shown in Table 1. The resulting blend was extruded and kneaded at a set temperature C3 = 260 ° C. using a single screw extruder with a vent (HW-40-28: 40 m / m, L / D = 28, manufactured by Tabata Machinery Co., Ltd.), and pellets Turned into. After drying the obtained pellet at 140 ° C. for 5 hours or more, using an injection molding machine (160MSP-10 type, manufactured by Mitsubishi Plastics), cylinder temperature C3 = 265 ° C., nozzle temperature N = 280 ° C. A flat plate sample having a thickness of 2 mm was obtained by injection molding. Moreover, the test piece for an Izod intensity | strength measurement was obtained on the same pelletization and injection molding conditions. The obtained molded product was evaluated, and the results are shown in Table 1.

(Examples 3 and 4)
Instead of the polyorganosiloxane-containing graft copolymer powder (SG-1) in Example 1, the polyorganosiloxane-containing graft copolymer powder (SG-2) obtained in Production Example 3 was used. Except for the above, a molded product was obtained in the same manner. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Examples 1 and 2)
In the same manner as in Example 1, except that the polyorganosiloxane powder (SR-1) obtained in Production Example 1 was used instead of the polyorganosiloxane-containing graft copolymer powder (SG-1). A molded product was obtained. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Examples 3 and 4)
In Example 1, instead of the polyorganosiloxane-containing graft copolymer powder (SG-1), a silicone-based light diffusing agent (crosslinked polymethylsilsesquioxane particles, Tospearl 2000B, average, manufactured by GE Toshiba Silicone Co., Ltd.) A molded product was obtained in the same manner except that the particle size was 4.0 μm. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Examples 5 and 6)
In Example 1, instead of the polyorganosiloxane-containing graft copolymer powder (SG-1), a silicone light diffusing agent (cross-linked polymethylsilsesquioxane particles, X-52-, manufactured by Shin-Etsu Chemical Co., Ltd.) was used. 1621, an average particle size of 5.4 μm) was used to obtain a molded product. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 7)
A molded product was obtained in the same manner as in Example 1 except that the polyorganosiloxane-containing graft copolymer powder (SG-1) was not used. The obtained molded product was evaluated, and the results are shown in Table 1.

(Example 5)
Adeka Stub 2112 (Asahi Denka Kogyo Co., Ltd.), an antioxidant, with respect to 100 parts by weight of polymethyl methacrylate resin (manufactured by CYRO, Acrylite H-12, total light transmittance 92.3% of 2 mm thick molded product) )) And 0.2 parts by weight of the polyorganosiloxane-containing graft copolymer powder (SG-1) obtained in Production Example 2 were blended in the number of parts shown in Table 1. The resulting blend was extruded and kneaded at a set temperature C3 = 200 ° C. using a single screw extruder with a vent (HW-40-28: 40 m / m, L / D = 28, manufactured by Tabata Machinery Co., Ltd.) and pellets Turned into. The obtained pellets were dried at 90 ° C. for 4 hours or more and then injected at an injection molding machine (160MSP-10 type, manufactured by Mitsubishi Plastics) at a cylinder temperature C3 = 250 ° C. and a nozzle temperature N = 255 ° C. A flat plate sample having a thickness of 2 mm was obtained by molding. Moreover, the test piece for an Izod intensity | strength measurement was obtained on the same pelletization and injection molding conditions. The obtained molded product was evaluated, and the results are shown in Table 1.

(Example 6)
Instead of the polyorganosiloxane-containing graft copolymer powder (SG-1) in Example 5, the polyorganosiloxane-containing graft copolymer powder (SG-2) obtained in Production Example 3 was used. Except for the above, a molded product was obtained in the same manner. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 8)
The same procedure as in Example 5 was repeated except that the polyorganosiloxane powder (SR-1) obtained in Production Example 1 was used instead of the polyorganosiloxane-containing graft copolymer powder (SG-1). A molded product was obtained. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 9)
In Example 5, instead of the polyorganosiloxane-containing graft copolymer powder (SG-1), a silicone-based light diffusing agent (cross-linked polymethylsilsesquioxane particles, Tospearl 2000B, average, manufactured by GE Toshiba Silicones Co., Ltd.) A molded product was obtained in the same manner except that the particle size was 4.0 μm. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 10)
In Example 5, instead of the polyorganosiloxane-containing graft copolymer powder (SG-1), a silicone-based light diffusing agent (crosslinked polymethylsilsesquioxane particles, X-52-, manufactured by Shin-Etsu Chemical Co., Ltd.) was used. 1621, an average particle size of 5.4 μm) was used to obtain a molded product. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 11)
A molded product was obtained in the same manner as in Example 5 except that the polyorganosiloxane-containing graft copolymer powder (SG-1) was not used. The obtained molded product was evaluated, and the results are shown in Table 1.

(Example 7)
In Production Example 2 with respect to 100 parts by weight of methyl methacrylate-styrene copolymer resin (manufactured by Nippon Steel Chemical Co., Ltd., Estyrene MS MS-600, total light transmittance of 91.3% of 2 mm-thick molded product) The obtained polyorganosiloxane-containing graft copolymer powder (SG-1) was blended in the number of parts shown in Table 1. The resulting blend was extruded and kneaded at a set temperature C3 = 180 ° C. using a single screw extruder with a vent (HW-40-28: 40 m / m, L / D = 28, manufactured by Tabata Machinery Co., Ltd.) and pellets Turned into. The obtained pellets were dried at 80 ° C. for 3 hours or more, and then injected using an injection molding machine (160MSP-10 type, manufactured by Mitsubishi Plastics) at a cylinder temperature C3 = 220 ° C. and a nozzle temperature N = 225 ° C. A flat plate sample having a thickness of 2 mm was obtained by molding. Moreover, the test piece for an Izod intensity | strength measurement was obtained on the same pelletization and injection molding conditions. The obtained molded product was evaluated, and the results are shown in Table 1.

(Example 8)
Instead of the polyorganosiloxane-containing graft copolymer powder (SG-1) in Example 7, the polyorganosiloxane-containing graft copolymer powder (SG-2) obtained in Production Example 3 was used. Except for the above, a molded product was obtained in the same manner. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 12)
The same procedure as in Example 7 was repeated except that the polyorganosiloxane powder (SR-1) obtained in Production Example 1 was used instead of the polyorganosiloxane-containing graft copolymer powder (SG-1). A molded product was obtained. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 13)
In Example 7, instead of the polyorganosiloxane-containing graft copolymer powder (SG-1), a silicone-based light diffusing agent (crosslinked polymethylsilsesquioxane particles, Tospearl 2000B, average, manufactured by GE Toshiba Silicones Co., Ltd.) A molded product was obtained in the same manner except that the particle size was 4.0 μm. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 14)
In Example 7, instead of the polyorganosiloxane-containing graft copolymer powder (SG-1), a silicone light diffusing agent (crosslinked polymethylsilsesquioxane particles, X-52-, manufactured by Shin-Etsu Chemical Co., Ltd.) was used. 1621, an average particle size of 5.4 μm) was used to obtain a molded product. The obtained molded product was evaluated, and the results are shown in Table 1.

(Comparative Example 15)
A molded product was obtained in the same manner as in Example 7, except that the polyorganosiloxane-containing graft copolymer powder (SG-1) was not used. The obtained molded product was evaluated, and the results are shown in Table 1.

  As is clear from Table 1, the examples are excellent in light transmittance (total light transmittance), light diffusibility (haze), Izod strength, appearance of the molded product, and powder characteristics.

  As described above, the present invention can provide a light diffusing resin composition excellent in physical properties, molding stability, and handleability. This light diffusing resin composition can be suitably used for, for example, a transmissive screen for projection televisions, a light diffusing plate for liquid crystal backlights, or a light diffusing plate that can be used for lighting covers, lighting signs, and the like.

Claims (9)

  A polyfunctional monomer (b-1) containing two or more polymerizable unsaturated bonds in the presence of 30 to 95 parts by weight of a latex polyorganosiloxane (a) having a volume average particle size of 0.8 to 25 μm ) Polymerizing 0 to 20 parts by weight of vinyl monomer (b) consisting of 100 to 50% by weight and other copolymerizable monomer (b-2) 0 to 50% by weight; A polyorganosiloxane-containing graft copolymer (A) obtained by polymerizing one or more stages of the body (c) 5 to 70 parts by weight (however, the sum of (a), (b) and (c) is 100 parts by weight) ), And at least one transparent resin (B) selected from the group consisting of thermoplastic resins and thermosetting resins, a light diffusing resin composition.   The polyorganosiloxane-containing graft copolymer (A) is a polyfunctional monomer (b-1) containing two or more polymerizable unsaturated bonds in the presence of 30 to 95 parts by weight of the polyorganosiloxane (a). 0.5 to 10 parts by weight of vinyl monomer (b) consisting of 100 to 50% by weight and other copolymerizable monomer (b-2) 0 to 50% by weight is polymerized, It is obtained by polymerizing 4.5 to 69.5 parts by weight of the monomer (c) (however, the total of (a), (b) and (c) is 100 parts by weight). The light diffusing resin composition according to claim 1.   The polyorganosiloxane (a) is obtained by polymerizing a linear or branched siloxane having a terminal group selected from a hydroxyl group, an amino group and a hydrolyzable group. The light diffusing resin composition according to claim 1 or 2.   4. The light diffusing resin composition according to claim 1, wherein the polymerization of the vinyl monomer (b) and / or the vinyl monomer (c) is carried out by emulsion polymerization. .   The vinyl monomer (c) is a (meth) acrylic acid ester monomer, an aromatic vinyl monomer, a vinyl cyanide monomer, a carboxyl group-containing vinyl monomer and vinyl chloride. From one to two or more kinds of monofunctional monomers selected from 50 to 100% by weight, and from one to two or more kinds of polyfunctional monomers containing two or more polymerizable unsaturated bonds from 0 to 50% by weight The light diffusing resin composition according to any one of claims 1 to 4, wherein   The polyorganosiloxane-containing graft copolymer (A) is contained in an amount of 0.01 to 500 parts by weight with respect to 100 parts by weight of the transparent resin (B), according to any one of claims 1 to 5. Light diffusing resin composition.   The light diffusing resin composition according to any one of claims 1 to 6, wherein the transparent resin (B) has a total light transmittance of 50% or more of a molded product having a thickness of 2 mm.   A light diffusing plate obtained from the light diffusing resin composition according to claim 1.   9. The light diffusing plate according to claim 8, wherein the total light transmittance is 10% or more and the haze is 40% or more.