JP5988602B2 - Thermoplastic resin composition for forming optical parts - Google Patents

Description

The present invention relates to an optical component for forming a thermoplastic resin composition which gives a transparent and and small optics birefringence.

  In recent years, in many fields, such as information display by liquid crystal display, information recording by optical disc, writing / erasing to optical disc by laser optical system, information printing by laser printer, information transmission by optical fiber, etc. Optical parts such as mirrors, optical disks, optical fibers, optical compensation films (retardation films, polarizing films, etc.) are used. In these optical components, birefringence, which is a phenomenon in which there is a difference in refractive index in at least two axial directions in the orthogonal three-dimensional axis direction, may be an important evaluation item. It is said that it is not preferable that the constituent material of the optical component exhibits large birefringence. For example, if a film having birefringence exists in the optical path, it will adversely affect image quality and signal reading performance. .

  Glass-based materials have been used for a long time as constituent materials for optical components, but resin materials such as polymethyl methacrylate resin and polycarbonate resin are used because of excellent molding processability, light weight, impact resistance, etc. It came to be able to. However, molecular orientation generated during molding may cause birefringence and impair the function as an optical component.

In addition, optical components or molding materials thereof are disclosed below.
Patent Document 1 includes a thermoplastic resin composition excellent in optical properties, containing a copolymer obtained by using styrene, maleic anhydride and / or phenylmaleimide, and a styrene / acrylonitrile copolymer. Things are listed.

  Patent Document 2 describes a non-birefringent optical resin material containing strontium carbonate needle crystal particles and a transparent cyclic olefin resin or polymethyl methacrylate resin. This composite material has a relationship in which, when both the resin bond chain and the inorganic fine particles (the long axis of the strontium carbonate needle crystal) are aligned in parallel, their orientation birefringence cancels each other. is there.

JP-A-61-204251 JP 2004-35347 A

An object of the present invention is to provide an optical component for forming the thermoplastic resin composition is transparent and gives a small optic birefringence.

The present invention is as follows.
1. A thermoplastic resin composition containing a thermoplastic resin and fine particles, and giving a transparent and low birefringence optical component,
The thermoplastic resin includes a structural unit derived from a (meth) acrylic acid alkyl ester and a structural unit derived from a vinyl cyanide compound, and a content ratio of the structural unit derived from the (meth) acrylic acid alkyl ester. Is 60% by mass or more (meth) acrylic thermoplastic resin with respect to 100% by mass of the thermoplastic resin,
The fine particles are composed of a graft resin having a volume average particle diameter of 50 to 500 nm, and the graft resin includes a structural unit derived from a polymerizable unsaturated monomer (a2) containing a (meth) acrylic acid alkyl ester ( (Co) polymer is a resin grafted to rubber polymer (a1) made of (meth) acrylic rubber polymer,
The content of the structural unit derived from the (meth) acrylic acid alkyl ester contained in the (co) polymer in the graft resin constituting the fine particles is 3 to 40% by mass with respect to the whole fine particles,
The content of the fine particles is 5 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin.
2. 2. The thermoplastic resin composition for forming an optical component as described in 1 above, wherein the polymerizable unsaturated monomer (a2) comprises the above (meth) acrylic acid alkyl ester, an aromatic vinyl compound, and a vinyl cyanide compound.
3. The proportions of the (meth) acrylic acid alkyl ester, the aromatic vinyl compound, and the vinyl cyanide compound are 40 to 90% by mass and 5 to 40% by mass, respectively, when the total of these is 100% by mass. 3. The thermoplastic resin composition for forming an optical component according to 2 above, which is 1% to 30% by mass.
4). The structural unit derived from the (meth) acrylic acid alkyl ester, the structural unit derived from the vinyl cyanide compound, and the structural unit derived from an aromatic vinyl compound. The thermoplastic resin for forming an optical component according to any one of claims 1 to 3, wherein the content ratios thereof are 60 to 85 mass%, 3 to 15 mass%, and 10 to 25 mass%, respectively. Composition.
5. 5. The thermoplastic resin composition for optical component formation according to any one of 1 to 4, wherein a difference between a refractive index of the thermoplastic resin and a refractive index of the fine particles is 0.02 or less.

In the present invention, “transparent” is defined as having a so-called light transmittance, that is, the total light transmittance measured according to ISO 13468-1 is 80% or more.
In the present invention, “birefringence” is an in-plane retardation (R0) measured by irradiating a film having a predetermined thickness with light having a wavelength of 590 nm under the conditions of a temperature of 23 ° C. and a humidity of 50% RH. Is evaluated by the calculated value of in-plane Δn according to the following formula. “Small birefringence” (hereinafter sometimes referred to as “low birefringence”) is defined as Δn being 0.00010 or less.
In-plane Δn = R0 / d
(R0: in-plane retardation (nm), d: film thickness (nm))
In the present invention, “refractive index” is a value measured according to ISO 489, and the difference in refractive index when comparing the two is evaluated by the absolute value of the calculated value.
In the present invention, the “volume average particle diameter” is different in the measurement method depending on the properties of the measurement sample. When the fine particles are dispersed in the liquid, the fine particles are dispersed in the solid by the light scattering method or the laser diffraction method. In the case of being dispersed, the value is measured by an image analysis method using an electron microscope.

According to the optical component for forming the thermoplastic resin composition of the present invention, it is possible to obtain transparency (optical transparency) and excellent optics to low birefringence. Structural units thermoplastic resin derived from a (meth) acrylic acid alkyl esters and, since it is (meth) acrylic thermoplastic resin comprising a structural unit derived from a vinyl cyanide compound, the properties particularly excellent.

The present invention will be described in detail below.
Each of the thermoplastic resin compositions for forming an optical component of the present invention includes a specific thermoplastic resin (hereinafter referred to as “thermoplastic resin (T)”) and fine particles (hereinafter referred to as “fine particles (A)”). And the content of the fine particles (A) is 5 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin (T).
In this specification, “(meth) acryl” refers to acryl and methacryl, “(meth) acrylate” refers to acrylate and methacrylate, “(meth) acryloyl group” refers to acryloyl group or methacryloyl group, “Polymer” means homopolymers and copolymers.

Specifically, the fine particles (A) according to the present invention include a rubber polymer (hereinafter referred to as “rubber polymer (a1)) composed of a (meth) acrylic rubber polymer having a volume average particle diameter of 50 to 500 nm. In the presence of (meth) acrylic acid alkyl ester (hereinafter referred to as “polymerizable unsaturated monomer (a2)”) (hereinafter referred to as “graft”). Fine particles made of a rubbery polymer reinforced graft resin (hereinafter also referred to as “graft resin”) contained in a resin composition (hereinafter referred to as “rubber reinforced resin”) obtained by “polymerization”. This graft resin is a resin in which a (co) polymer containing a structural unit derived from the polymerizable unsaturated monomer (a2) is grafted to the rubbery polymer (a1), and the rubbery polymer part And a (co) polymer part containing a structural unit derived from the polymerizable unsaturated monomer (a2).
The rubber-reinforced resin obtained by graft polymerization usually has a structural unit derived from the polymerizable unsaturated monomer (a2) that is not grafted to the rubbery polymer (a1) in addition to the graft resin. Including (co) polymer (hereinafter referred to as “ungrafted polymer”), this ungrafted polymer is not fine particles (A).
The fine particles (A) are not agglomerates of the graft resin, and a preferred size will be described later.

  The rubbery polymer (a1) used for forming the fine particles (A) may be a homopolymer or a copolymer as long as it is rubbery at 25 ° C. The rubbery polymer (a1) may be a crosslinked polymer or a non-crosslinked polymer.

The rubber polymer (a1) is a (meth) acrylic rubber polymer. These can be used alone or in combination of two or more.
In the present invention, from the viewpoint of transparency and impact resistance of the molded article obtained, a diene-based rubbery polymer is preferably Iga, in the present invention, from the viewpoint of weather resistance and heat resistance, (meth) acrylic A rubbery polymer is used .

Examples of the diene rubber polymer include homopolymers such as polybutadiene, polyisoprene, and polychloroprene; styrene / butadiene copolymer, styrene / butadiene / styrene copolymer, acrylonitrile / butadiene copolymer, acrylonitrile / styrene / Styrene / butadiene copolymers such as butadiene copolymers; styrene / isoprene copolymers, styrene / isoprene / styrene copolymers, styrene / isoprene copolymers such as acrylonitrile / styrene / isoprene copolymers; natural rubber Etc. These copolymers may be block copolymers or random copolymers. In addition, hydrogenated products of these copolymers can also be used.
Each of the above copolymers can further contain a structural unit derived from a vinyl monomer such as (meth) acrylic acid alkyl ester. When the fine particles (A) obtained using these copolymers are used in combination with a thermoplastic resin, the difference in refractive index between them may be further reduced, and the transparency can be improved.

The gel content of the diene rubbery polymer is preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more, regardless of the type. When a diene rubbery polymer having a high gel content is used, a molded product excellent in transparency, appearance, impact resistance and the like can be obtained.
The gel content of the diene rubber polymer can be determined by the following method, for example.
First, 1 g of a diene rubbery polymer is put into 100 ml of toluene and left at room temperature for 48 hours. Then, it filters using a 100 mesh sieve and isolate | separates into the filtrate containing an insoluble part and a soluble part. After separation, toluene is distilled off from the filtrate containing toluene-soluble matter, and the obtained solid is dried and weighed (mass is defined as Wt grams). From this weighed value, the gel content is calculated by the following formula.
Gel content (mass%) = [1 (g) −Wt (g)] × 100

  The (meth) acrylic rubbery polymer is a polymer containing a structural unit derived from a (meth) acrylic acid alkyl ester, and may be a homopolymer or a copolymer containing this structural unit. May be. This copolymer may be a copolymer containing two or more kinds of structural units derived from (meth) acrylic acid alkyl ester, and may be a structural unit derived from (meth) acrylic acid alkyl ester and other vinyl-based units. It may be a copolymer containing structural units derived from monomers. Furthermore, the (meth) acrylic rubbery polymer may be a crosslinked polymer or a non-crosslinked polymer.

  Examples of the (meth) acrylic acid alkyl ester compound used for forming the structural unit derived from the (meth) acrylic acid alkyl ester constituting the (meth) acrylic rubbery polymer include methyl (meth) acrylate, ( (Meth) ethyl acrylate, (meth) acrylate n-propyl, (meth) acrylate isopropyl, (meth) acrylate n-butyl, (meth) acrylate isobutyl, (meth) acrylate tert-butyl, (meth) Sec-butyl acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, Decyl (meth) acrylate, dodecyl (meth) acrylate, cyclo (meth) acrylate Hexyl, and the like. These compounds can be used alone or in combination of two or more. Of these, compounds having 1 to 14 carbon atoms in the alkyl group in the ester moiety are preferred, and n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred.

  In addition, when the (meth) acrylic rubbery polymer is a copolymer, the compound (vinyl monomer) used for forming other structural units is carbon other than (meth) acrylic acid alkyl ester. -It can be set as the compound which has one or more carbon-carbon double bonds, and / or the compound which has two or more carbon-carbon double bonds. When the fine particles (A) in the case of using such a copolymer are used together with a thermoplastic resin, the difference in refractive index between the two may be made smaller, and the transparency can be improved.

  Examples of the compound having one carbon-carbon double bond include aromatic vinyl compounds, vinyl cyanide compounds, amide group-containing unsaturated compounds, alkyl vinyl ethers, and vinylidene chloride. In addition, these compounds may be used independently and may be used in combination of 2 or more type.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, ethylstyrene, tert-butylstyrene, 1,1-diphenylstyrene, N, N-diethyl. -P-aminostyrene, N, N-diethyl-p-aminomethylstyrene, vinylpyridine, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, tribromostyrene, fluorostyrene, vinylnaphthalene, etc. .
Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.
Examples of the amide group-containing unsaturated compound include acrylamide and methacrylamide.
Examples of the alkyl vinyl ether include compounds having 1 to 6 carbon atoms in the alkyl group constituting the alkyl portion.

  In addition, as a compound having two or more carbon-carbon double bonds, a bifunctional aromatic vinyl compound, a bifunctional (meth) acrylic ester, a trifunctional (meth) acrylic ester, a tetrafunctional (meta ) Acrylic acid ester, pentafunctional (meth) acrylic acid ester, hexafunctional (meth) acrylic acid ester, polyhydric alcohol (meth) acrylic acid ester, and the like. In addition, these compounds may be used independently and may be used in combination of 2 or more type.

Examples of the bifunctional aromatic vinyl compound include divinylbenzene and divinyltoluene.
Examples of the bifunctional (meth) acrylic acid ester include 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, neopentyl glycol diacrylate, allyl (meth) acrylate, neopentyl glycol dimethacrylate, and triethylene glycol diacrylate. Examples include acrylate and triethylene glycol dimethacrylate.
Examples of the trifunctional (meth) acrylic acid ester include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, and the like.
Examples of the tetrafunctional (meth) acrylic acid ester include pentaerythritol tetraacrylate and pentaerythritol tetramethacrylate.
Examples of the pentafunctional (meth) acrylic acid ester include pentaerythritol pentaacrylate and pentaerythritol pentamethacrylate.
Examples of the hexafunctional (meth) acrylic acid ester include dipentaerythritol hexaacrylate and dipentaerythritol hexamethacrylate.
Examples of the (meth) acrylic acid ester of the polyhydric alcohol include (poly) ethylene glycol dimethacrylate.
In addition, allyl methacrylate, diallyl phthalate, diallyl malate, diallyl fumarate, triallyl cyanurate, triallyl isocyanurate, bis (acryloyloxyethyl) ether of bisphenol A, and the like can be used.
Of these, allyl methacrylate and triallyl cyanurate are preferred.

  As the (meth) acrylic rubbery polymer, a copolymer containing a structural unit derived from (meth) acrylic acid alkyl ester is preferable. In this case, when the total amount of all the structural units constituting the copolymer is 100% by mass, the content of the structural unit derived from the (meth) acrylic acid alkyl ester is preferably 60 to 99.99% by mass, More preferably, it is 75-99.9 mass%, More preferably, it is 90-99.5 mass%.

The gel content of the (meth) acrylic rubbery polymer is preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass or more, regardless of the type. When a (meth) acrylic rubbery polymer having a high gel content is used, a molded article excellent in impact resistance and appearance can be obtained.
In addition, the gel content rate of the said (meth) acrylic-type rubber-like polymer can be calculated | required with the following method, for example.
First, about 0.2 gram of (meth) acrylic rubbery polymer is weighed (mass is Wr gram), charged into 25 ml of toluene and stirred. Then, it is allowed to stand at 25 ° C. for 48 hours, and is filtered using a 200-mesh wire mesh (mass is Wm gram) weighed in advance to separate into insoluble and soluble components. Immediately after the separation, the insoluble matter is weighed together with the filtered wire mesh (mass is W1 gram), and the weight value (Wm) of the wire mesh is subtracted from the weight value (W1), and the insoluble matter swollen with toluene. Weighing value is obtained. Next, since the insoluble matter swollen with toluene contains toluene, it is air-dried at 25 ° C. for 12 hours, and subsequently dried at 60 ° C. for 12 hours using a vacuum dryer. Toluene contained in the minute is removed by drying. The insoluble matter after drying is weighed together with the wire mesh (the mass is W2 grams), and the weight value (Wm) of the wire mesh is subtracted from the weight value (W2) to obtain the dry weight of the insoluble matter (the mass is Wd grams). And). From these weighed values, the gel content is calculated by the following formula.
Gel content (% by mass) = [Wd (g) / Wr (g)] × 100
= [{W2 (g) -Wm (g)} / Wr (g)] × 100

  On the other hand, the polymerizable unsaturated monomer (a2) used for the formation of the fine particles (A) contains (meth) acrylic acid alkyl ester and can be copolymerized with the (meth) acrylic acid alkyl ester. The vinyl monomer may be included. Other vinyl monomers include aromatic vinyl compounds, cyanide vinyl compounds, maleimide compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds (unsaturated acids), hydroxyl group-containing unsaturated compounds, oxazolines. And group-containing unsaturated compounds. These compounds may be used alone or in combination of two or more. When the fine particles (A) in the case of using such other vinyl monomers are used together with the thermoplastic resin, the difference in refractive index between the two may be further reduced, and the transparency is improved. be able to.

The lower limit of the content of the (meth) acrylic acid alkyl ester contained in the polymerizable unsaturated monomer (a2) is determined from the viewpoint of the transparency and low birefringence of the obtained molded product. It is preferably 30% by mass, more preferably 50% by mass, and still more preferably 60% by mass with respect to 100% by mass of the monomer (a2). The upper limit is preferably 100% by mass, more preferably 95% by mass.
The content of the (meth) acrylic acid alkyl ester contained in the polymerizable unsaturated monomer (a2) depends on the type of the rubbery polymer (a1) in order to obtain a desired refractive index in the fine particles (A). In some cases, it is effective to select an appropriate amount and set the following usage amount. For example, in the case where the rubber polymer (a1) is a diene rubber polymer and the fine particles (A) have a refractive index in the range of 1.5122 to 1.5226, a polymerizable non-polymerizable polymer is used. Content of the (meth) acrylic-acid alkylester contained in a saturated monomer (a2) becomes like this. Preferably it is 50-90 mass%, More preferably, it is 60-80 mass%, More preferably, it is 65-75 mass%. In order to obtain fine particles (A) in which the rubber polymer (a1) is a (meth) acrylic rubber polymer and the refractive index is in the range of 1.4632 to 1.5206, The content of the (meth) acrylic acid alkyl ester contained in the polymerizable unsaturated monomer (a2) is preferably 99% by mass or less, and more preferably 50 to 90% by mass.

  Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, tert-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, (meth) acrylic 2-ethylhexyl acid, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, (meth) Examples include benzyl acrylate. These compounds can be used alone or in combination of two or more. Of these, methyl methacrylate is preferred.

  The aromatic vinyl compound is not particularly limited as long as it is a compound having at least one vinyl bond and at least one aromatic ring. However, it is assumed to be an aromatic hydrocarbon having no substituent such as a functional group. Examples thereof include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyltoluene, vinylxylene, vinylnaphthalene and the like. These compounds can be used alone or in combination of two or more. Of these, styrene and α-methylstyrene are preferred.

  Examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, ethacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile and the like. These compounds can be used alone or in combination of two or more. Of these, acrylonitrile is preferred.

  Examples of the maleimide compound include maleimide, N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-dodecylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (4-methyl). Phenyl) maleimide, N- (2,6-dimethylphenyl) maleimide, N- (2,6-diethylphenyl) maleimide, N-benzylmaleimide, N-naphthylmaleimide, N-cyclohexylmaleimide and the like. These compounds can be used alone or in combination of two or more.

Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like. These compounds can be used alone or in combination of two or more.
Examples of the carboxyl group-containing unsaturated compound (unsaturated acid) include (meth) acrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, and cinnamic acid. These compounds can be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing unsaturated compound include 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (Meth) acrylic acid 2-hydroxybutyl, (meth) acrylic acid 3-hydroxybutyl, (meth) acrylic acid 4-hydroxybutyl, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, (meth) acrylic Compound obtained by adding ε-caprolactone to 2-hydroxyethyl acid, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, o-hydroxy-α-methylstyrene, m-hydroxy-α-methylstyrene P-hydroxy α-methylstyrene, 2-hydroxymethyl-α-methylstyrene, 3-hydroxymethyl-α-methylstyrene, 4-hydroxymethyl-α-methylstyrene, 4-hydroxymethyl-1-vinylnaphthalene, 7-hydroxymethyl- 1-vinylnaphthalene, 8-hydroxymethyl-1-vinylnaphthalene, 4-hydroxymethyl-1-isopropenylnaphthalene, 7-hydroxymethyl-1-isopropenylnaphthalene, 8-hydroxymethyl-1-isopropenylnaphthalene, p- Vinylbenzyl alcohol, 3-hydroxy-1-propene, 4-hydroxy-1-butene, cis-4-hydroxy-2-butene, trans-4-hydroxy-2-butene, 3-hydroxy-2-methyl-1- And propene. These compounds can be used alone or in combination of two or more.

  Other vinyl monomers are preferably aromatic vinyl compounds and vinyl cyanide compounds, and polymerizable unsaturated monomers (a2) are (meth) acrylic acid alkyl esters, aromatic vinyl compounds and vinyl cyanide. It is particularly preferred that it consists of a compound.

  When the polymerizable unsaturated monomer (a2) further contains an aromatic vinyl compound and a vinyl cyanide compound, the ratio of these compounds is such that when the total of both is 100% by mass, It is selected from the viewpoints of molding processability during production, transparency of the resulting molded product, low birefringence, chemical resistance, hydrolysis resistance, impact resistance, rigidity, appearance, and the like. When the rubber polymer (a1) is a diene rubber polymer, the ratios of the aromatic vinyl compound and the vinyl cyanide compound are preferably 40 to 95% by mass and 5 to 60% by mass, respectively, more preferably. They are 50-90 mass% and 10-50 mass%, More preferably, they are 60-85 mass% and 15-40 mass%. When the rubber polymer (a1) is an acrylic rubber polymer, the ratio of the aromatic vinyl compound and the vinyl cyanide compound is preferably 40 to 95% by mass and 5 to 60% by mass, respectively. Preferably they are 50-93 mass% and 7-50 mass%, More preferably, they are 60-90 mass% and 10-40 mass%.

In the present invention, the rubber polymer (a1) is a diene rubber polymer, and the polymerizable unsaturated monomer (a2) is a (meth) acrylic acid alkyl ester, an aromatic vinyl compound, and cyanide. In the case of a vinyl compound, the ratio of these compounds is preferably 40 to 90% by mass, 5 to 40% by mass, and 1 to 30% by mass, more preferably, when the total of the three is 100% by mass. Is 50 to 85 mass%, 7 to 35 mass% and 2 to 25 mass%, more preferably 60 to 80 mass%, 10 to 30 mass% and 4 to 20 mass%.
Further, the rubber polymer (a1) is an acrylic rubber polymer, and the polymerizable unsaturated monomer (a2) is composed of (meth) acrylic acid alkyl ester, aromatic vinyl compound and vinyl cyanide compound. In this case, the ratio of these compounds is preferably 5 to 90% by mass, 5 to 80% by mass, and 5 to 45% by mass, more preferably 7 to 7%, when the total of the three is 100% by mass. In some cases, it may be 50 mass%, 40-75 mass%, and 5-30 mass%.

The method for producing the fine particles (A) is not particularly limited, and may be emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, or a combination thereof. The polymerization temperature of the polymerizable unsaturated monomer (a2) is preferably 40 ° C to 95 ° C, more preferably 50 ° C to 90 ° C.

  When the fine particles (A) are produced, the polymerization is started by supplying the polymerizable unsaturated monomer (a2) all together in the reaction system in the presence of the total amount of the rubbery polymer (a1). Alternatively, the polymerization may be performed while being divided or continuously fed. The polymerization may be started by supplying the polymerizable unsaturated monomer (a2) all at once in the presence or absence of the rubbery polymer (a1), or divided or continuously. May be supplied. At this time, the remainder of the rubber polymer (a1) may be supplied in a batch, divided, or continuously during the reaction.

As a method for producing the fine particles (A), emulsion polymerization is particularly preferable.
When performing emulsion polymerization, a polymerization initiator, a chain transfer agent (molecular weight regulator), an emulsifier, water, and the like are used.

  Examples of the polymerization initiator include organic peroxides, azo compounds, inorganic peroxides, and redox polymerization initiators.

  Examples of the organic peroxide include tert-butyl hydroperoxide, tert-amyl-tert-butyl peroxide, tert-butyl-tert-hexyl peroxide, tert-amyl-tert-hexyl peroxide, di (tert-hexyl). ) Peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1- Bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydropa Oxide, 1,3-bis (tert-butylperoxy) -m-isopropyl) benzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, diisopropylbenzene peroxide, tert-butyl kumi Ruperoxide, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxylaurate, tert-butylperoxymonocarbonate, bis (tert-butylcyclohexyl) peroxy Examples include dicarbonate, tert-butyl peroxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, and the like.

  Examples of the azo compound include 2,2′-azobis (isobutyronitrile), 1,1-azobis (cyclohexane-1-carbonitrile), azocumene, and 2,2′-azobis (2-methylbutyronitrile). 2,2′-azobisdimethylvaleronitrile, 4,4′-azobis (4-cyanovaleric acid), 2- (tert-butylazo) -2-cyanopropane, 2,2′-azobis (2,4,4) 4-trimethylpentane), 2,2′-azobis (2-methylpropane), dimethyl 2,2′-azobis (2-methylpropionate) and the like.

Examples of the inorganic peroxide include potassium persulfate, sodium persulfate, and ammonium persulfate.
Further, as a redox type polymerization initiator, sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, ferrous sulfate and the like are used as reducing agents, potassium peroxodisulfate, hydrogen peroxide, cumene hydroperoxide, What used tert-butyl hydroperoxide etc. as the oxidizing agent can be used.

The amount of the polymerization initiator used is preferably 0.05 to 10% by mass with respect to the total amount of the polymerizable unsaturated monomer (a2).
The polymerization initiator can be supplied to the reaction system all at once or continuously.

  Examples of the chain transfer agent include mercaptans such as octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-hexyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, tert-tetradecyl mercaptan; Examples include α-methylstyrene dimers. These can be used alone or in combination of two or more.

The amount of the chain transfer agent used is preferably 0.01 to 5% by mass with respect to the total amount of the polymerizable unsaturated monomer (a2).
The chain transfer agent can be supplied to the reaction system all at once or continuously.

Examples of the emulsifier include anionic surfactants and nonionic surfactants. Examples of the anionic surfactants include sulfates of higher alcohols, sulfates of higher fatty acids, ammonium salts or alkali metal salts (sodium salts, potassium salts, etc.) of organic acids. Examples of the organic acid include (higher) fatty acid, (higher) alkylsulfonic acid, (higher) alkyldisulfonic acid, sulfonated (higher) fatty acid, (higher) fatty acid ester sulfonic acid, sulfonic acid of higher alcohol ether, (higher) Examples include fatty acid amide alkylol sulfate, alkyl benzene sulfonic acid, alkyl phenol sulfonic acid, alkyl naphthalene sulfonic acid, (higher) aliphatic phosphoric acid and the like.
Examples of nonionic surfactants include polyethylene glycol alkyl ester compounds and alkyl ether compounds.

  The amount of the emulsifier used is preferably 0.1 to 10% by mass with respect to the total amount of the polymerizable unsaturated monomer (a2).

  Emulsion polymerization can be performed by a well-known method according to kinds, such as a polymerizable unsaturated monomer (a2) and a polymerization initiator. The latex obtained by this emulsion polymerization is usually coagulated with a rubber-reinforced resin containing fine particles (A) with a coagulant to form a powder or the like. Thereafter, it is purified by washing with water, etc., dried and collected. For coagulation, conventionally known coagulants are used, and inorganic salts such as calcium chloride, magnesium sulfate, magnesium chloride, and sodium chloride; inorganic acids such as sulfuric acid and hydrochloric acid are used.

  When the fine particles (A) and the ungrafted polymer are separated from the rubber-reinforced resin containing fine particles (A) obtained as described above, for example, 10 g of rubber-reinforced resin is added to 100 to 200 ml of acetone (rubber In the case where the polymer (a1) is an acrylic rubber, acetonitrile is used), and the mixture is shaken at 25 ° C. for 2 to 3 hours using a shaker or the like. The method of separating and recovering is applied. The insoluble component corresponds to the fine particles (A), and the acetone soluble component (acetonitrile soluble component) corresponds to the ungrafted polymer.

In the fine particles (A), the graft ratio of the (co) polymer containing a structural unit derived from the polymerizable unsaturated monomer (a2) is from the viewpoint of the transparency and low birefringence of the resulting molded product. , Preferably 40 to 150%, more preferably 45 to 100%, still more preferably 50 to 80%. When this graft ratio is too low, the transparency, mechanical strength and appearance of the resulting molded product may be deteriorated. On the other hand, if the graft ratio is too high, the molding processability of the thermoplastic resin composition for forming an optical component , the transparency of the resulting molded product, the mechanical strength, and the like may decrease.

The graft ratio can be determined by the following formula.
Graft rate (%) = {(S−T) / T} × 100
In the formula, S represents 1 gram of rubber-reinforced resin obtained by graft polymerization in 20 ml of acetone (acetonitrile is used when the rubbery polymer is an acrylic rubber), and is shaken using a shaker. (Temperature 25 ° C., 2 hours), then centrifuge using a centrifuge (temperature 5 ° C., rotation speed 23,000 rpm, 1 hour) to separate the insoluble matter and the soluble matter. The mass (g) of the minute, and T is the mass (g) of the rubbery polymer (a1) contained in 1 gram of the rubber-reinforced resin. The mass of the rubbery polymer (a1) can be calculated from the polymerization prescription and the polymerization conversion rate.

  The graft ratio is, for example, the type and amount of polymerization initiator used in graft polymerization, the type and amount of chain transfer agent, the supply method and supply time of the polymerizable unsaturated monomer (a2), The polymerization temperature and the like can be adjusted by appropriately selecting.

The volume average particle diameter of the fine particles (A) is 50 to 500 nm, more preferably 50 to 400 nm , and still more preferably 50 from the viewpoints of transparency, low birefringence, mechanical strength and the like of the obtained molded product. ~ 350 nm.
The volume average particle diameter can be measured by subjecting the reaction solution after graft polymerization or the fine particles (A) separated from the rubber-reinforced resin to a light scattering method or a laser diffraction method.

The content of the structural unit derived from the (meth) acrylic acid alkyl ester contained in the (co) polymer part of the graft resin constituting the fine particles (A) is such that the rubber polymer (a1) is a diene rubber. When it is a polymer, it is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and still more preferably 15 to 35% by mass with respect to the entire fine particles (A), and the rubbery polymer (a1) Is a (meth) acrylic rubbery polymer, it is 3 to 40% by mass, more preferably 5 to 30% by mass, based on the whole fine particles (A).

The refractive index of the fine particles (A) depends on the type of the rubbery polymer (a1), and is preferably 1.4782 to 1.5206 from the viewpoint of the transparency and low birefringence of the obtained molded product. is there. In particular, when the rubbery polymer is a diene rubber such as polybutadiene, the preferable refractive index is 1.5140 to 1.5200, more preferably 1.5150 to 1.5190, and still more preferably 1.5106 to 1. 5180. When the rubbery polymer is an acrylic rubber, the preferable refractive index is 1.50050 to 1.5200, more preferably 1.5100 to 1.5190, and still more preferably 1.5130 to 1.5180.
The refractive index can be measured using a film formed using the fine particles (A) as a test piece.

The fine particles (A), the thermoplastic resin (hereinafter, "thermoplastic resin (B)" hereinafter) with reference et al is in a transparent and and fine particles giving small moldings birefringence. The thermoplastic resin (B) includes an aromatic vinyl resin containing a structural unit derived from an aromatic vinyl compound, and a (meth) acrylic resin (hereinafter referred to as “meth) acrylic acid alkyl ester”. (meth) acrylic-based thermoplastic resin "hereinafter), polyolefin resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyester resins, polycarbonate resins, polyamide resins, it may be at least one selected from a fluororesin or the like In the present invention, the structural unit derived from a (meth) acrylic acid alkyl ester and the structural unit derived from the (meth) acrylic acid alkyl ester, including the structural unit derived from a vinyl cyanide compound. However, 60 mass% or more (meth) acrylic heat with respect to 100 mass% of the thermoplastic resin Plastic resin.

The lower limit of the content of the structural unit derived from the (meth) acrylic acid alkyl ester contained in the (meth) acrylic thermoplastic resin is the above (from the viewpoint of the transparency and low birefringence of the obtained molded product ( It is 60 mass% with respect to 100 mass% of meth) acrylic-type thermoplastic resins, More preferably, it is 70 mass%. The upper limit is preferably 100% by mass, more preferably 95% by mass.
In addition, this (meth) acrylic acid alkyl ester is preferably a compound exemplified as the (meth) acrylic acid alkyl ester contained in the polymerizable unsaturated monomer (a2), and particularly preferably methyl methacrylate.

The (meth) monomer used to form the thermoplastic acrylic resins, (meth) including an acrylic acid alkyl ester and another copolymerizable vinyl monomer. Other vinyl monomers include aromatic vinyl compounds, cyanide vinyl compounds, maleimide compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds (unsaturated acids), hydroxyl group-containing unsaturated compounds, oxazolines. Examples thereof include a group-containing unsaturated compound , and in the present invention, a vinyl cyanide compound is included . The other vinyl monomer can be the compound exemplified as the polymerizable unsaturated monomer (a2).

  In the present invention, the (meth) acrylic thermoplastic resin is preferably a copolymer obtained using a (meth) acrylic acid alkyl ester, an aromatic vinyl compound and a vinyl cyanide compound. In this case, the content ratio of the structural unit derived from the (meth) acrylic acid alkyl ester, the structural unit derived from the aromatic vinyl compound, and the structural unit derived from the vinyl cyanide compound is 100% by mass in total. In each case, it is preferably 60 to 85% by mass, 10 to 25% by mass and 3 to 15% by mass, respectively.

  The method for producing the (meth) acrylic thermoplastic resin is not particularly limited, and emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization can be used. Of these, solution polymerization and bulk polymerization are preferred.

The intrinsic viscosity [η] of the (meth) acrylic thermoplastic resin is preferably from 0.20 to 0.80 dl / g, more preferably from the viewpoint of molding processability, transparency, low birefringence and the like. It is 25-0.60 dl / g, More preferably, it is 0.28-0.40 dl / g.
The intrinsic viscosity [η] can be determined, for example, in the following manner.
The intrinsic viscosity [η] is determined by dissolving the measurement sample in methyl ethyl ketone, preparing five solutions having different concentrations, and measuring the reduced viscosity of each solution at 30 ° C. using an Ubbelohde viscosity tube.

In order to use the fine particles (A) in combination with the thermoplastic resin (B) made of the (meth) acrylic thermoplastic resin, to obtain a molded product excellent in transparency and low birefringence, the fine particles (A ) Content is 5 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin (B).

The thermoplastic resin composition for forming an optical component of the present invention may contain various additives as long as transparency and low birefringence are not impaired.

The thermoplastic resin composition for forming an optical component of the present invention comprises an alkyl (meth) acrylate in the presence of the thermoplastic resin (B) and a rubbery polymer (a1) having a volume average particle diameter of 50 to 500 nm. A composition obtained using a rubber-reinforced resin containing fine particles (A) made of a graft resin obtained by polymerizing a polymerizable unsaturated monomer (a2) containing an ester is preferable. In this case, since the rubber-reinforced resin contains an ungrafted polymer as described above, in this preferable thermoplastic resin composition for forming an optical component , the thermoplastic resin (T) is the thermoplastic resin (B). and consisting of ungrafted polymer.

(Meth) acrylic thermoplastic resin containing structural unit derived from (meth) acrylic acid alkyl ester, wherein the thermoplastic resin (T) is blended as an ungrafted polymer and a thermoplastic resin (B) separately When it consists of, the ratio of the total amount of the structural unit derived from the (meth) acrylic-acid alkylester contained in a thermoplastic resin (T) becomes like this. Preferably it is 60-85 mass%.
In this case, the intrinsic viscosity [η] of the thermoplastic resin (T) is preferably 0.20 to 0.80 dl / g, more preferably from the viewpoint of moldability, transparency, low birefringence, and the like. It is 0.25 to 0.60 dl / g, more preferably 0.28 to 0.40 dl / g. In order to recover the thermoplastic resin (T) from the mixture of the thermoplastic resin (T) and the fine particles (A), for example, the mixture is put into acetone or acetonitrile, and shaken using a shaker. There is a method of removing insolubles after centrifugation (temperature: 25 ° C., 2 hours), followed by centrifugation for 1 hour using a centrifuge at a temperature of 5 ° C. and a rotational speed of 23,000 rpm. The method for measuring the intrinsic viscosity [η] is as described above.

In the present invention, another preferable thermoplastic resin composition for forming an optical component includes a (meth) acrylic thermoplastic resin containing a structural unit derived from an alkyl (meth) acrylate and a structure derived from an aromatic vinyl compound. A composition comprising a thermoplastic resin (T) comprising a unit and a thermoplastic resin comprising a structural unit derived from a vinyl cyanide compound, and fine particles (A).

  In the present invention, the difference (absolute value) between the refractive index of the thermoplastic resin (T) and the refractive index of the fine particles (A) is preferably 0.0200 or less from the viewpoint of the transparency of the obtained molded product. More preferably, it is 0.0100 or less, More preferably, it is 0.0060 or less, Most preferably, it is 0.

In the thermoplastic resin composition for forming an optical component of the present invention, the content of the fine particles (A) is 5 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin (T), and has low birefringence, From the viewpoints of mechanical strength, moldability, etc., the amount is preferably 5 to 80 parts by mass, more preferably 10 to 50 parts by mass.

As described above, the thermoplastic resin composition for forming an optical component of the present invention may contain an additive, but may be a composition containing no additive. Preferred compositions of the latter aspect (hereinafter, referred to as "rubber-reinforced resin composition") is the presence of a rubbery polymer having a volume average particle diameter of 50 to 500 nm (a1), (meth) acrylic acid alkyl ester and A vinyl system containing fine particles (A) obtained by graft polymerization of a polymerizable unsaturated monomer (a2) containing a vinyl cyanide compound and a structural unit derived from this polymerizable unsaturated monomer (a2) It is a mixture consisting of a copolymer.

  The rubber-reinforced resin composition may be composed of a rubber-reinforced resin including a graft resin and an ungrafted polymer obtained by graft polymerization, and is blended with the rubber-reinforced resin and polymerizable unsaturated It may consist of a vinyl copolymer containing a structural unit derived from the monomer (a2). That is, the vinyl copolymer may be composed of an ungrafted polymer, or a structure derived from this ungrafted polymer and a separately mixed polymerizable unsaturated monomer (a2). And a copolymer containing units.

  The content of the structural unit derived from the polymerizable unsaturated monomer (a2) contained in the vinyl copolymer is determined from the viewpoint of transparency and low birefringence of the obtained molded product. Preferably it is 2-80 mass% with respect to a polymer, More preferably, it is 2.5-60 mass%, More preferably, it is 3-50 mass%.

  The intrinsic viscosity [η] of the vinyl copolymer is preferably 0.20 to 0.80 dl / g, more preferably 0.25 to 0, from the viewpoints of moldability, transparency, low birefringence, and the like. .60 dl / g, more preferably 0.28 to 0.40 dl / g. In order to recover the vinyl copolymer from the mixture of the vinyl copolymer and the fine particles (A), for example, the mixture is put into acetone or acetonitrile and shaken using a shaker ( There is a method of removing the insoluble matter by centrifuging for 1 hour using a centrifuge at a temperature of 5 ° C. and a rotation speed of 23,000 rpm.

  In the rubber-reinforced resin composition, the content of the fine particles (A) is 5 to 100 parts by mass with respect to 100 parts by mass of the vinyl copolymer, and has low birefringence, mechanical strength, and moldability. From the viewpoint of the above, it is preferably 5 to 80 parts by mass, more preferably 10 to 50 parts by mass.

Hereinafter, the additive which can be mix | blended with the thermoplastic resin composition for optical component formation of this invention is illustrated. Additives include fillers, plasticizers, antioxidants, UV absorbers, anti-aging agents, flame retardants, lubricants, weathering stabilizers, light stabilizers, heat stabilizers, antistatic agents, water repellents, oil repellents , Antifoaming agents, antibacterial agents, preservatives, colorants (pigments and dyes), fluorescent whitening agents, conductivity-imparting agents and the like.

  Examples of the filler include heavy calcium carbonate, colloidal calcium carbonate, light calcium carbonate, magnesium carbonate, zinc carbonate, aluminum hydroxide, magnesium hydroxide, carbon black, clay, talc, fumed silica, calcined silica, precipitated silica, Ground silica, fused silica, kaolin, diatomaceous earth, zeolite, titanium oxide, quicklime, iron oxide, zinc oxide, barium oxide, aluminum oxide, magnesium oxide, aluminum sulfate, glass fiber, carbon fiber, glass balloon, shirasu balloon, saran Examples include balloons and phenol balloons. These can be used alone or in combination of two or more.

  Examples of the plasticizer include phthalic acid ester, trimellitic acid ester, pyromellitic acid ester, aliphatic monobasic acid ester, aliphatic dibasic acid ester, phosphoric acid ester, polyhydric alcohol ester, epoxy plasticizer, high Examples include molecular plasticizers and chlorinated paraffins. These can be used alone or in combination of two or more.

  Examples of the antioxidant include hindered amine compounds, hydroquinone compounds, hindered phenol compounds, sulfur-containing compounds, and phosphorus-containing compounds. These can be used alone or in combination of two or more.

  Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, and triazine compounds. These can be used alone or in combination of two or more.

  Examples of the anti-aging agent include naphthylamine compounds, diphenylamine compounds, p-phenylenediamine compounds, quinoline compounds, hydroquinone derivative compounds, monophenol compounds, bisphenol compounds, trisphenol compounds, polyphenol compounds, thiols. Examples thereof include bisphenol compounds, hindered phenol compounds, phosphite compounds, imidazole compounds, nickel dithiocarbamate salts, phosphoric compounds, and the like. These can be used alone or in combination of two or more.

  Examples of the flame retardant include organic flame retardants, inorganic flame retardants, and reactive flame retardants. These can be used alone or in combination of two or more.

  Organic flame retardants include brominated epoxy compounds, brominated alkyltriazine compounds, brominated bisphenol epoxy resins, brominated bisphenol phenoxy resins, brominated bisphenol polycarbonate resins, brominated polystyrene resins, brominated crosslinked polystyrene resins Halogenated flame retardants such as brominated bisphenol cyanurate resin, brominated polyphenylene ether, decabromodiphenyl oxide, tetrabromobisphenol A and oligomers thereof; trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, tripentyl phosphate Hexyl phosphate, tricyclohexyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate Phosphate esters such as phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, dimethyl ethyl phosphate, methyl dibutyl phosphate, ethyl dipropyl phosphate, hydroxyphenyl diphenyl phosphate, modified compounds thereof, condensed phosphate ester compounds, phosphorus Examples thereof include phosphorus flame retardants such as phosphazene derivatives containing elements and nitrogen elements; guanidine salts; silicone compounds.

Examples of the inorganic flame retardant include aluminum hydroxide, antimony oxide, magnesium hydroxide, zinc borate, zirconium compound, molybdenum compound, and zinc stannate.
Examples of the reactive flame retardant include tetrabromobisphenol A, dibromophenol glycidyl ether, brominated aromatic triazine, tribromophenol, tetrabromophthalate, tetrachlorophthalic anhydride, dibromoneopentyl glycol, poly (pentabromobenzyl poly). Acrylate), chlorendic acid (hett acid), chlorendic anhydride (hett acid anhydride), brominated phenol glycidyl ether, dibromocresyl glycidyl ether, and the like.

  Examples of the lubricant include wax, silicone, and lipid. These can be used alone or in combination of two or more.

The thermoplastic resin composition for forming an optical component of the present invention can be produced by kneading the fine particles (A) and the thermoplastic resin (T) together with additives used as necessary. A particularly preferred production method is, as described above, polymerization comprising a (meth) acrylic acid alkyl ester in the presence of the thermoplastic resin (B) and the rubbery polymer (a1) having a volume average particle diameter of 50 to 500 nm. A rubber-reinforced resin containing fine particles (A) made of a graft resin obtained by polymerizing the polymerizable unsaturated monomer (a2), and kneading together with additives used as necessary, by a method of production is there. In kneading, conventionally known kneading apparatuses such as a twin screw extruder, a single screw extruder, a heatable twin or single screw feeder, a feeder ruder, a Banbury mixer, a roll mill, and the like can be used.

  The kneading temperature is appropriately selected depending on the types of the fine particles (A) and the thermoplastic resin (T), but is usually a temperature equal to or higher than the melting temperature of the component having the lowest melting temperature contained in the thermoplastic resin (T). Preferably, the temperature is 10 ° C. or more higher than the melting temperature.

By using the thermoplastic resin composition for forming an optical component of the present invention, a molded product excellent in transparency and low birefringence can be obtained. The shape of the molded product is selected according to the purpose, application, etc., and can be flat, curved, linear, massive, or the like.

The total light transmittance of the molded product is 80% or more, preferably 85% or more, more preferably 88% or more.
Further, the in-plane Δn of the molded product is 0.00010 or less, preferably 0.00008 or less, more preferably 0.00005 or less. This in-plane Δn can be calculated from, for example, an in-plane retardation measured using light having a wavelength of 590 nm using a film having a thickness of 10 to 200 μm as a measurement sample.
In-plane Δn = R0 / d
(R0: in-plane retardation (nm), d: film thickness (nm))

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded. In the following, “part” and “%” are based on mass unless otherwise specified.

1. Measurement Method A method relating to the evaluation of the rubber polymer used in the following experimental examples, the obtained fine particles, the thermoplastic resin (rubber reinforced resin), and the thermoplastic resin composition for forming an optical component is shown below.

1-1. Volume average particle diameter of rubbery polymer and fine particles The volume average particle diameter of the rubbery polymer, which is a raw material for producing fine particles, and the fine particles dispersed in the latex, is manufactured using “Microtrack UPA150 Model 9340” manufactured by Nikkiso Co., Ltd. It was measured by a light scattering method.

1-2. Graft ratio in graft resin contained in rubber reinforced resin 1 g of rubber reinforced resin is put into 20 ml of acetone or acetonitrile, shaken using a shaker (temperature 25 ° C., 2 hours), and then centrifuged. Then, the mixture was centrifuged for 1 hour at a temperature of 5 ° C. and a rotational speed of 23,000 rpm. Next, acetone-insoluble or acetonitrile-insoluble and acetone-soluble or acetonitrile-soluble are separated, and acetone-insoluble or acetonitrile-insoluble is weighed (this mass (g) is S), and rubber reinforcement From the mass of the rubbery polymer contained in 1 gram of the resin (this mass (g) is T), the graft ratio was obtained by the following formula.
Graft rate (%) = {(S−T) / T} × 100

1-3. Intrinsic viscosity [η]
Intrinsic viscosity of acetone soluble component or acetonitrile soluble component in rubber reinforced resin, intrinsic viscosity of vinyl-based (co) polymer, and intrinsic viscosity of acetone soluble component or acetonitrile soluble component in thermoplastic resin composition, It was measured by the method described above.

1-4. Refractive index In accordance with ISO 489, an Abbe refractometer “NAR-3T” (model name) manufactured by Atago Co., Ltd. was used and measured under the conditions of D-line, temperature of 23 ° C. and humidity of 50% RH.

1-5. Birefringence A film having a thickness of 100 μm is used as a test piece, using an automatic birefringence meter “KOBRA21ADH” (model name) manufactured by Oji Scientific Co., Ltd., under the conditions of a wavelength of 590 nm, a temperature of 23 ° C. and a humidity of 50% RH. The phase difference R0 (nm) was measured, and the in-plane Δn was calculated based on the following formula. When the in-plane Δn was 0.0001 or less, it was evaluated that the low birefringence was excellent.
In-plane Δn = R0 / d
(D: film thickness (converted to nm))

1-6. Total light transmittance Using a film having a thickness of 100 μm as a test piece, measurement was performed using “haze-gard plus” (trade name) manufactured by BYK-GARDNER according to ISO 13468-1.

2. Production and evaluation of fine particles and rubber reinforced resin (R)
Production Example 1-1
In a separable flask having an internal volume of 10 liters equipped with a stirrer, latex (a-1) (solid content concentration 50%) containing 30 parts of polybutadiene rubber having a volume average particle diameter of 250 nm and a gel content of 90% is placed. After the preparation, 0.5 part of potassium oleate, 0.2 part of glucose, 0.2 part of sodium pyrophosphate, 0.01 part of ferrous sulfate and 100 parts of deionized water were added. Next, the mixture was heated while stirring, and a monomer mixture consisting of 49 parts of methyl methacrylate, 16 parts of styrene, 5 parts of acrylonitrile, 0.4 part of diisopropylbenzene hydroperoxide and 0.8 part of t-dodecyl mercaptan. Was polymerized at 70 ° C. while continuously added over 5 hours. The obtained latex is subjected to coagulation, water washing and drying, and a powdery rubber-reinforced resin (R-1) containing fine particles of grafted polybutadiene and free methyl methacrylate / styrene / acrylonitrile copolymer is contained. (Polymerization conversion 98%) was obtained.
The graft ratio of the grafted polybutadiene (acetone insoluble matter) obtained by the acetone treatment of the rubber reinforced resin was 60%, and the volume average particle diameter was 260 nm. The liberated methyl methacrylate / styrene / acrylonitrile copolymer (acetone soluble component) had a refractive index of 1.5171.
Table 1 shows the evaluation results of the obtained fine particles and rubber-reinforced resin (R-1).

Production Examples 1-2 to 1-8
Fine particles and rubber-reinforced resin (R) were prepared in the same manner as in Production Example 1-1 except that latex containing polybutadiene rubber and a polymerizable unsaturated monomer were used as the rubbery polymer in the proportions shown in Table 1. -2) to (R-8) were produced (see Table 1).

Preparation Example 1-9
Acrylic polymers obtained by emulsion polymerization, wherein the content of structural units derived from n-butyl acrylate and structural units derived from allyl methacrylate are 99% and 1%, respectively, and the weight average particle diameter is 284 nm. After charging 100 parts of rubber and 110 parts of water into a glass reactor, the temperature was raised in a nitrogen stream while stirring. When the temperature reached 40 ° C., an aqueous solution in which 0.3 part of glucose, 1.2 parts of sodium pyrophosphate and 0.01 part of ferrous sulfate were dissolved in 20 parts of water (hereinafter referred to as “RED aqueous solution”) An aqueous solution in which 0.4 part of tert-butyl hydroperoxide (hereinafter referred to as “BHP”) and 2.4 part of disproportionated potassium rosinate are dissolved in 30 parts of water (hereinafter referred to as “CAT aqueous solution”). )) Was added to the reactor. Immediately thereafter, 100 parts of a monomer mixture composed of 74% styrene and 26% acrylonitrile and the remaining 70% of the CAT aqueous solution were continuously added over 3 hours and 3 hours 30 minutes, respectively, to carry out polymerization. It was. Polymerization was carried out by raising the temperature to 75 ° C. from the beginning and then holding at 75 ° C. Then, 180 minutes after the start of the polymerization, the remaining 14% of the RED aqueous solution was added to the reactor and held at the same temperature for 60 minutes to complete the polymerization. The obtained latex is subjected to coagulation, washing with water and drying to obtain a powdery rubber-reinforced resin (R-9) containing fine particles of grafted acrylic rubber and free styrene / acrylonitrile copolymer. It was.
Table 2 shows the evaluation results of the obtained fine particles and rubber-reinforced resin (R-9).

Production Example 1-10 to 1-11
An acrylic rubber latex as shown in Table 2, except for using a polymerizable unsaturated monomer shown in Table 2, in the same manner as in Preparation Example 1-9, fine particles and the rubber-reinforced resin (R-10) ~ ( R-11) was produced (see Table 2).

3. Production of vinyl-based (co) polymer (V) Synthesis Example 1-1
An autoclave with an internal volume of 10 liters was charged with 73 parts of methyl methacrylate, 20 parts of styrene, 7 parts of acrylonitrile, 20 parts of toluene and 0.5 part of tert-dodecyl mercaptan and polymerized at 150 ° C. for 5 hours with stirring. A copolymer (V-1) was obtained (polymerization conversion: 70%).
Table 3 shows the evaluation results of the obtained copolymer (V-1).

Synthesis Examples 1-2 to 1-4
Copolymers (V-2) to (V-4) were produced in the same manner as in Synthesis Example 1-1 except that the polymerizable unsaturated monomers shown in Table 3 were used (see Table 3).

Synthesis Example 1-5
A glass reactor was charged with 2 parts of sodium oleate and 110 parts of water, and the temperature was raised in a nitrogen stream while stirring. When 40 ° C was reached, 0.3 parts of potassium persulfate was added to the reactor. Immediately thereafter, a monomer mixture consisting of 80 parts of methyl methacrylate and 20 parts of acrylonitrile was continuously added over 3 hours for polymerization. Polymerization was carried out by raising the temperature to 75 ° C. from the beginning and then holding at 75 ° C. The obtained latex was subjected to coagulation, washing with water and drying to obtain a powdery acrylonitrile / methyl methacrylate copolymer (V-5).
Table 3 shows the evaluation results of the obtained copolymer (V-5).

Synthesis Example 1-6
An acrylonitrile / styrene / methyl methacrylate copolymer (V-6) was produced in the same manner as in Synthesis Example 1-5 except that the polymerizable unsaturated monomer shown in Table 3 was used (see Table 3). .

4). Production and evaluation of thermoplastic resin composition for optical component formation (1)
Reference example 1
100 parts of rubber reinforced resin (R-1) obtained in Preparation Example 1-1 and pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] as a heat stabilizer After 0.4 parts (trade name “IRGANOX1010”, manufactured by BASF) and 0.2 parts of calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) as a lubricant are uniformly mixed with a high-speed mixer, It melt-kneaded at 260 degreeC using the axial extruder (L / D = 32), and was pelletized with the strand cut method. Next, using a film forming machine equipped with a T die (die width: 1600 mm, lip interval: 0.4 mm) and an extruder with a screw diameter of 115 mm, the resulting pellet was heated to a melting temperature of 230 ° C. The resin was discharged from the T die to obtain a thin body. Then, this thin-walled body was brought into close contact with a cast roll whose surface temperature was controlled at 70 ° C. with an air knife and cooled and solidified to produce a film. The birefringence and total light transmittance of this film were measured, and the results are shown in Table 4.

Reference example 2
The same as Reference Example 1 except that 50 parts of the rubber-reinforced resin (R-1) obtained in Preparation Example 1-1 and 50 parts of the copolymer (V-1) obtained in Synthesis Example 1-1 were used. Then, a film was prepared and evaluated (see Table 4).

Reference Examples 3-7 and Comparative Examples 1-2
The rubber-reinforced resin (R) and vinyl-based (co) polymer (V) shown in Table 4 were each pelletized in the same manner as in Reference Example 2 except that they were used in the proportions shown in Table 4, and then the film was formed. Prepared and evaluated (see Table 4).

5. Production and evaluation of thermoplastic resin composition for optical component formation (2)
Example 1
The same as Reference Example 1 except that 40 parts of the rubber-reinforced resin (R-9) obtained in Production Example 1-9 and 50 parts of the copolymer (V-5) obtained in Synthesis Example 1-5 were used. Then, a film was prepared and evaluated (see Table 5).

Examples 2 to 4 and Comparative Examples 4 to 5
Except having used the rubber reinforced resin (R) and copolymer (V) shown in Table 5 in the ratio shown in Table 5, respectively, after pelletizing like Example 1 , a film was produced and evaluated. (See Table 5).

According to the optical component for forming the thermoplastic resin composition of the present invention, it is possible to obtain transparency (optical transparency) and excellent optics to low birefringence.
The obtained optical component is suitable for optical products and the like. Specifically, a lens, a prism, a light guide plate, an optical waveguide, a polarizing plate protective film, an optical compensation film (viewing angle improvement film, brightness enhancement film, retardation) Widely used as an optical filter, an antireflection film, and the like.

Claims (5)

A thermoplastic resin composition containing a thermoplastic resin and fine particles, and giving a transparent and low birefringence optical component,
The thermoplastic resin includes a structural unit derived from a (meth) acrylic acid alkyl ester and a structural unit derived from a vinyl cyanide compound, and a content ratio of the structural unit derived from the (meth) acrylic acid alkyl ester Is 60% by mass or more (meth) acrylic thermoplastic resin with respect to 100% by mass of the thermoplastic resin,
The fine particles are composed of a graft resin having a volume average particle diameter of 50 to 500 nm, and the graft resin includes a structural unit derived from a polymerizable unsaturated monomer (a2) containing a (meth) acrylic acid alkyl ester ( (Co) polymer is a resin grafted to rubber polymer (a1) made of (meth) acrylic rubber polymer,
The content of the structural unit derived from the (meth) acrylic acid alkyl ester contained in the (co) polymer in the graft resin constituting the fine particles is 3 to 40% by mass with respect to the whole fine particles,
The content of the fine particles is 5 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin.   The thermoplastic resin composition for forming an optical component according to claim 1, wherein the polymerizable unsaturated monomer (a2) comprises the alkyl (meth) acrylate, an aromatic vinyl compound, and a vinyl cyanide compound. .   The proportions of the (meth) acrylic acid alkyl ester, the aromatic vinyl compound, and the vinyl cyanide compound are 40 to 90% by mass and 5 to 40% by mass, respectively, when the total of these is 100% by mass. The thermoplastic resin composition for forming an optical component according to claim 2, wherein the thermoplastic resin composition is 1% and 30% by mass.   The (meth) acrylic thermoplastic resin is the structural unit derived from the (meth) acrylic acid alkyl ester, the structural unit derived from the vinyl cyanide compound, and a structural unit derived from an aromatic vinyl compound. The thermoplastic resin for forming an optical component according to any one of claims 1 to 3, wherein the content ratios thereof are 60 to 85 mass%, 3 to 15 mass%, and 10 to 25 mass%, respectively. Composition.   The thermoplastic resin composition for forming an optical component according to any one of claims 1 to 4, wherein a difference between a refractive index of the thermoplastic resin and a refractive index of the fine particles is 0.02 or less.