JP7229226B2 - Optical styrene resin composition and optical parts - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical styrene resin composition and an optical component.

Styrene-based resins have excellent properties such as transparency, rigidity, low water absorption, and dimensional stability, and are excellent in moldability. It is widely used as industrial materials, food packaging containers, miscellaneous goods, and the like. In addition, it is also used in optical members such as light guide plates as applications that take advantage of its transparency.

Backlights for liquid crystal displays include a direct type backlight in which the light source is arranged in front of the display device and an edge light type backlight in which the light source is arranged on the side. Light guide plates are incorporated into edge-light backlights and play the role of guiding light from the sides to liquid crystal panels. be. As a styrenic resin composition used for such a light guide plate, Patent Document 1 describes a styrenic resin composition that exhibits a small change in transmittance even after long-term use.

WO2013/094642

However, in the prior art described in the above document, while it is possible to suppress changes in transmittance during long-term use, there is a problem that the uniform surface luminescence and long-term uniform surface luminescence are not sufficient.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a styrenic resin composition and an optical component which are excellent in initial uniform surface luminescence and long-term uniform surface luminescence. With the goal.

According to the present invention, (a) a styrene resin, (b) a phosphorus antioxidant and/or a phenolic antioxidant, and (c) an anthraquinone compound, in 100% by mass of the styrene resin composition The content of (b) is 0.02 to 1% by mass, and the content of (c) with respect to the total mass of the resin component is 0.1 to 90 ppb. goods are provided.

In order to achieve the above object, the present inventors have made intensive studies, and found that the above object can be achieved by using a specific amount of a phosphorus antioxidant and / or a phenol antioxidant in combination with an anthraquinone compound. We have found that it can be achieved, and have completed the present invention.

Various embodiments of the present invention are illustrated below. Various embodiments shown below can be combined with each other.
Preferably, the average transmittance at a wavelength of 380 nm to 780 nm at an optical path length of 115 mm is 80% or more (however, the average transmittance is 127 obtained by injection molding at a cylinder temperature of 230 ° C. and a mold temperature of 50 ° C. A test piece with a thickness of 115 × 85 × 3 mm is cut from a plate-shaped product with a thickness of × 127 × 3 mm, and the end face is polished by buffing to prepare a test piece having a mirror surface on the end face.
Preferably, the ratio of the transmittance (t480) at a wavelength of 480 nm to the transmittance (t580) at a wavelength of 580 nm has the following relationship.
0.96<t580/t480<1.04
Preferably, (a) a styrene resin, (b) a phosphorus antioxidant and/or a phenolic antioxidant, and (c) an anthraquinone compound, and the above ( The content of b) is 0.02 to 1% by mass, and the average transmittance at a wavelength of 380 nm to 780 nm at an optical path length of 115 mm is 80% or more (however, the average transmittance is at a cylinder temperature of 230 ° C., a mold A test piece with a thickness of 115×85×3 mm was cut out from a plate-shaped molding with a thickness of 127×127×3 mm obtained by injection molding at a temperature of 50° C. The end surface was polished by buffing and had a mirror surface. The ratio of the transmittance (t480) at a wavelength of 480 nm to the transmittance (t580) at a wavelength of 580 nm has the following relationship.
0.96<t580/t480<1.04
Preferably, an optical component made of the optical styrene resin composition.

The heat-resistant styrenic resin composition of the present invention provides a styrenic resin composition and an optical component that are excellent in initial uniform surface luminescence and long-term uniform surface luminescence.

The present invention will be described in detail below.

<<Styrene resin>>
The styrenic resin of the present invention can be obtained by polymerizing styrenic monomers. Styrenic monomers are aromatic vinyl monomers such as styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, ethylstyrene and pt-butylstyrene. or a mixture of two or more, preferably styrene. In addition, it may be copolymerized with a monomer that can be copolymerized with a styrene-based monomer as long as the characteristics of the present invention are not impaired. Examples include vinyl cyanide monomers such as lonitrile, α,β-ethylenically unsaturated carboxylic acids such as maleic anhydride and fumaric acid, and imide monomers such as phenylmaleimide and cyclohexylmaleimide. Among these, polymers composed only of styrene-based monomers are preferred, and styrene homopolymers are particularly preferred.
The styrene resin composition is preferably composed of a styrene resin and various additives, and the proportion of the styrene resin in 100% by mass of the styrene resin composition is, for example, 90 to 99.96% by mass. and preferably 95 to 99.96% by mass. Specifically, the ratio of the styrene resin is, for example, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.96% by mass. It may be within a range between two.

When the styrene-based resin is a styrene-(meth)acrylic acid copolymer resin obtained by copolymerizing a styrene-based monomer and (meth)acrylic acid, the content of styrene-based monomer units in the styrene-based resin It is preferable that the amount is 80.0 to 99.9% by mass and the content of (meth)acrylic acid units is 0.1 to 20.0% by mass. However, the total content of styrene-based monomer units and (meth)acrylic acid units is 100% by mass. (Meth)acrylic acid includes acrylic acid, methacrylic acid, etc., and methacrylic acid is preferred.

The measurement of the (meth)acrylic acid unit content in the styrenic resin is carried out at room temperature. 0.5 g of styrene resin was weighed and dissolved in a mixed solution of toluene/ethanol = 8/2 (volume ratio), followed by neutralization titration with a 0.1 mol/L ethanol solution of potassium hydroxide to detect the end point. , the content of (meth)acrylic acid units based on mass is calculated from the amount of potassium hydroxide ethanol solution used. In addition, an automatic potentiometric titrator can be used, and the measurement can be performed with AT-510 manufactured by Kyoto Electronics Industry Co., Ltd. The content of (meth)acrylic acid units in the styrene-based resin can be adjusted by adjusting the composition ratio of the styrene-based monomer and the (meth)acrylic acid monomer as raw materials during the polymerization of the styrene-based resin. Alternatively, a styrenic resin containing (meth)acrylic acid units and a styrenic resin not containing (meth)acrylic acid units can be blended to adjust the composition.

Polymerization methods for styrene resins include known styrene polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. In terms of quality and productivity, bulk polymerization and solution polymerization are preferred, and continuous polymerization is preferred. Examples of solvents that can be used include alkylbenzenes such as benzene, toluene, ethylbenzene and xylene, ketones such as acetone and methyl ethyl ketone, and aliphatic hydrocarbons such as hexane and cyclohexane.

A polymerization initiator and a chain transfer agent may be used, if necessary, during the polymerization of the styrenic resin. As the polymerization initiator, radical polymerization initiators are preferred, and known and commonly used ones include, for example, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, 2,2- Peroxyketals such as di(4,4-di-t-butylperoxycyclohexyl)propane, 1,1-di(t-amylperoxy)cyclohexane, cumene hydroperoxide, t-butyl hydroperoxide and the like Hydroperoxides, t-butyl peroxyacetate, alkyl peroxides such as t-amyl peroxy isononanoate, t-butyl cumyl peroxide, di-t-butyl peroxide, dicumyl peroxide, di-t - dialkyl peroxides such as hexyl peroxide, peroxyesters such as t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxyisopropyl carbonate, polyethers peroxycarbonates such as tetrakis(t-butylperoxycarbonate), N,N'-azobis(cyclohexane-1-carbonitrile), N,N'-azobis(2-methylbutyronitrile), N,N' -azobis(2,4-dimethylvaleronitrile), N,N'-azobis[2-(hydroxymethyl)propionitrile] and the like, and these can be used alone or in combination of two or more. . Chain transfer agents include aliphatic mercaptans, aromatic mercaptans, pentaphenylethane, α-methylstyrene dimer and terpinolene.

In the case of continuous polymerization, the polymerization reaction is controlled by adjusting the polymerization temperature, etc., so as to achieve the target molecular weight, molecular weight distribution, and reaction conversion rate using a well-known complete mixing tank type stirring tank, tower type reactor, etc. in the polymerization process. be done. The polymerization solution containing the polymer exiting the polymerization step is transferred to the devolatilization step to remove unreacted monomers and polymerization solvent. The devolatilization process consists of a vacuum devolatilization tank with a heater and a devolatilization extruder with a vent. The molten polymer that has exited the devolatilization step is transferred to the granulation step. In the granulation step, the molten resin is extruded in strands from a multi-hole die and processed into pellets by a cold cut method, an air hot cut method, or an underwater hot cut method.

<< Phosphorus-based antioxidant / Phenol-based antioxidant >>
The styrenic resin composition of the present invention contains at least one of a phosphorus antioxidant and a phenolic antioxidant as an essential component. Preferably, it contains both a phosphorus antioxidant and a phenolic antioxidant.

The phosphorus antioxidant preferably contains 0.02 to 1% by mass in 100% by mass of the styrene resin composition, more preferably 0.02 to 0.50% by mass, and 0.02 to 0 It is more preferable to contain 0.30% by mass. Further, the phenolic antioxidant preferably contains 0.02 to 1% by mass in 100% by mass of the styrene resin composition, more preferably 0.02 to 0.50% by mass, and 0.02 It is more preferable to contain up to 0.30% by mass. This is because when the phosphorus-based or phenol-based antioxidant is added in the above content, the long-term uniform surface luminescence is excellent. The content of the phosphorus antioxidant and the phenolic antioxidant in 100% by mass of the styrene resin composition is specifically, for example, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1% by mass and exemplified here It may be in a range between any two of the numbers.

Phosphorus-based antioxidants are phosphites, which are trivalent phosphorus compounds. Phosphorus antioxidants, for example, tris (2,4-di-tert-butylphenyl) phosphite, 2,2'-methylenebis (4,6-di-tert-butyl-1-phenyloxy) (2- ethylhexyloxy)phosphorus, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylenediphosphinic acid, 3,9-bis(2 ,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, cyclic neopentanetetraylbis(2,4-di -t-butylphenyl phosphite), distearyl pentaerythritol diphosphite, bis(nonylphenyl) pentaerythritol diphosphite, bis-[2-methyl-4,6-bis-(1,1-dimethylethyl)phenyl ] ethyl phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4′-biphenylenedi phosphonite and the like. As the phosphorus antioxidant, those having excellent hydrolysis resistance are preferable, and tris(2,4-di-tert-butylphenyl)phosphite, 2,2'-methylenebis(4,6-di-tert- Butyl-1-phenyloxy)(2-ethylhexyloxy) phosphorous, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, 3,9-bis(2,6-di-tert-butyl-4-methyl phenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane. Particularly preferred is tris(2,4-di-tert-butylphenyl)phosphite. Phosphorus-based antioxidants may be used alone or in combination of two or more.

A phenolic antioxidant is an antioxidant having a phenolic hydroxyl group in its basic skeleton. Phenolic antioxidants include, for example, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 3,9-bis[2-[3-(3-tert-butyl-4 -hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, ethylenebis(oxyethylene)bis[3-(5 -tert-butyl-4-hydroxy-m-tolyl)propionate], 4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis[(dodecylthio)methyl]-o-cresol, 2,4 -dimethyl-6-(1-methylpentadecyl)phenol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], DL-α-tocopherol, 2-t-butyl -6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]- 4,6-di-t-pentylphenyl acrylate, 4,4′-thiobis(6-t-butyl-3-methylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t -butylphenyl)butane, 4,4'-butylidenebis(3-methyl-6-t-butylphenol), bis-[3,3-bis-(4'-hydroxy-3'-tert-butylphenyl)-butanoic acid ]-glycol ester and the like. Octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methyl Phenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4 -hydroxy-m-tolyl)propionate], and pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Phenolic antioxidants may be used alone or in combination of two or more.

As described above, there are a wide variety of phosphorus antioxidants and phenolic antioxidants. Among them, phosphorus antioxidants are selected from (B1-1) to (B1-4) shown below It is at least one selected, and it is particularly preferable that the phenolic antioxidant is at least one selected from (B2-1) to (B2-4) shown below.

(B1-1) tris (2,4-di-tert-butylphenyl) phosphite (B1-2) 2,2'-methylenebis (4,6-di-tert-butyl-1-phenyloxy) (2- Ethylhexyloxy) phosphorous (B1-3) bis(2,4-dicumylphenyl) pentaerythritol diphosphite (B1-4) 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane

(B2-1) Octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (B2-2) 3,9-bis[2-[3-(3-tert-butyl-4 -hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (B2-3)ethylenebis(oxyethylene)bis[ 3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate]
(B2-4) pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]

Phosphorus-based antioxidants and phenol-based antioxidants can be added by adding and mixing them during the polymerization, devolatilization, or granulation processes of styrene-based resins, or by extruders or injection molding machines during molding. A method of mixing, and a method of diluting and mixing a resin composition in which a hydrophilic additive is adjusted to a high concentration with an additive-free styrene resin to a target content, etc., are not particularly limited.

<<Anthraquinone compound>>
The styrenic resin composition of the present invention contains an anthraquinone compound as an essential component. The content of the anthraquinone compound relative to the total mass of the resin components in the styrene resin composition is preferably 0.1 to 90 ppb, more preferably 1 to 70 ppb, even more preferably 5 to 50 ppb, and particularly preferably 15 to 45 ppb. This is because when the anthraquinone-based compound is added in the above content, initial and long-term uniform surface luminescence is excellent. Specifically, the content of the anthraquinone compound is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 , 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 , 90 ppb, and may be in the range between any two of the values exemplified herein.

Examples of anthraquinone compounds include the following. The names listed below are COLOR INDEX GENERIC NAMEs. Ｄｉｓｐｅｒｓｅ Ｂｌｕｅ１４、Ｄｉｓｐｅｒｓｅ Ｂｌｕｅ６０、Ｄｉｓｐｅｒｓｅ Ｂｌｕｅ１９７、Ｄｉｓｐｅｒｓｅ Ｂｌｕｅ１９８、Ｄｉｓｐｅｒｓｅ Ｂｌｕｅ３３４、Ｄｉｓｐｅｒｓｅ Ｂｌｕｅ７２、Ｓｏｌｖｅｎｔ Ｂｌｕｅ１１、Ｓｏｌｖｅｎｔ Ｂｌｕｅ３５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ３６、Ｓｏｌｖｅｎｔ Ｂｌｕｅ４５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ５９、Ｓｏｌｖｅｎｔ Ｂｌｕｅ６３、Ｓｏｌｖｅｎｔ Ｂｌｕｅ６７、Ｓｏｌｖｅｎｔ Ｂｌｕｅ７８、Ｓｏｌｖｅｎｔ Ｂｌｕｅ８３、Ｓｏｌｖｅｎｔ Ｂｌｕｅ８７、Ｓｏｌｖｅｎｔ Ｂｌｕｅ９４ 、Ｓｏｌｖｅｎｔ Ｂｌｕｅ９５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ９７、Ｓｏｌｖｅｎｔ Ｂｌｕｅ１０４、Ｓｏｌｖｅｎｔ Ｂｌｕｅ１０５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ１２２、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ１３、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３３、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３４、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ１４、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３１、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３６、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３７、Ｄｉｓｐｅｒｓｅ Ｖｉｏｌｅｔ２６、Ｄｉｓｐｅｒｓｅ Ｖｉｏｌｅｔ２８、Ｄｉｓｐｅｒｓｅ Ｖｉｏｌｅｔ３１、Ｄｉｓｐｅｒｓｅ Ｖｉｏｌｅｔ５７、Ｓｏｌｖｅｎｔ Green3, Solvent Green20, Solvent Green28.

<<Other Additives>>
Mineral oil may be contained in the styrene-based resin composition as long as it does not impair the colorless transparency of the present invention. It also contains internal lubricants such as stearic acid and ethylenebisstearylamide, and additives such as sulfur-based antioxidants, lactone-based antioxidants, UV absorbers, hindered amine-based stabilizers, antistatic agents, and external lubricants. It's okay if it is. Ethylenebisstearylamide is suitable as the external lubricant, and the content thereof is preferably 30 to 200 ppm in the resin composition.

Ultraviolet absorbers have the function of suppressing deterioration and coloration due to ultraviolet rays, and include, for example, benzophenone-based, benzotriazole-based, triazine-based, benzoate-based, salicylate-based, cyanoacrylate-based, oxalic acid anilide-based, and malonic acid esters. and formamidine-based UV absorbers. These may be used alone or in combination of two or more, and may be used in combination with a light stabilizer such as a hindered amine.

The styrenic resin composition of the present invention can be molded by injection molding, extrusion molding, compression molding, blow molding, and other molding methods according to the purpose, and the shape is not limited. For example, if it is a plate-shaped molded article, it can be processed into a light guide plate or the like. The obtained molded product is used as an optical member that functions by allowing light to pass through the inside of the molded product such as a light guide plate. An optical member such as a light guide plate preferably has excellent uniform surface luminescence because the distance (optical path length) through which light passes is long. Here, "excellent in uniform surface luminescence" means that the material has excellent transmittance and small wavelength dependence of light absorption.

Regarding the transmittance, the average transmittance at a wavelength of 380 nm to 780 nm at an optical path length of 115 mm is preferably 80% or more, more preferably 82.5% or more, and even more preferably 84% or more. However, the above average transmittance is obtained by cutting a 115 × 85 × 3 mm thick test piece from a 127 × 127 × 3 mm thick plate-shaped molded product obtained by injection molding at a cylinder temperature of 230 ° C and a mold temperature of 50 ° C. shall be measured using a test piece having a mirror surface on the end face prepared by polishing the end face by buffing. In addition, the absolute value of the difference between the average transmittance after storage at 80° C. for 1000 hours and the initial average transmittance is preferably 2.0% or less, more preferably 1.5% or less, and 1.2% or less. It is even more preferable to have

The wavelength dependence of light absorptance can be evaluated, for example, by the ratio (t580/t480) of the transmittance (t480) at a wavelength of 480 nm and the transmittance (t580) at a wavelength of 580 nm. In the present invention, the ratio (t580/t480) is preferably 0.96<t580/t480<1.04, more preferably 0.97<t580/t480<1.03, and 0.96<t580/t480<1.03. More preferably, 98<t580/t480<1.02. Here, that the wavelength dependence of the light absorptance is small means that the ratio (t580/t480) is close to 1 in principle. Specifically, the ratio (t580/t480) is, for example, 0.97, 0.98, 0.99, 1.00, 1.01, 1.02, 1.03. may be in the range between any two of

The transmittance at an optical path length of 115 mm was measured by the following procedure. Using pellets of the styrene-based resin composition, injection molding was performed at a cylinder temperature of 230°C and a mold temperature of 50°C to form a plate-like molded product of 127 x 127 x 3 mm thickness. The samples evaluated here for long-term thermal stability were stored in an oven at 80° C. for 1000 hours. Next, a test piece having a thickness of 115×85×3 mm was cut out from the plate-shaped molded product, and the end faces were polished by buffing to prepare a plate-shaped molded product having mirror surfaces on the end faces. For the plate-shaped molded article after polishing, using an ultraviolet-visible spectrophotometer V-670 manufactured by JASCO Corporation, the size of 20 × 1.6 mm, the incident light with a spread angle of 0 °, the wavelength at the optical path length of 115 mm Spectral transmittance from 350 nm to 800 nm was measured.

A light guide plate receives light from the end face (side surface) of a plate-shaped molded product, and guides the light to the front surface (light-emitting surface) of the molded product by the reflection pattern formed on the rear surface (non-light-emitting surface) of the molded product. It is a member that has the function of emitting surface light. A reflective pattern can be formed by methods such as a screen printing method, an injection molding method, a laser method, and an inkjet method. When processing a plate-like molding into a light guide plate, it is preferable to polish the light incident surface or the entire end surface to make a mirror surface. In addition, a prism pattern or the like can be provided on the front surface (light-emitting surface) of the plate-like molded product in order to improve the uniformity of emitted light. The pattern on the front or rear surface of the plate-shaped molded product can be formed during molding of the plate-shaped molded product.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples.

(Manufacture of styrene resin)
A polymerization process is configured by connecting in series a first reactor, a second reactor, which is a complete mixing type stirring tank, and a third reactor, which is a plug flow type reactor with a static mixer, and the conditions shown in Table 1 Manufacture of styrenic resin was carried out. The capacity of each reactor was 39 liters for the first reactor, 39 liters for the second reactor, and 16 liters for the third reactor. A raw material solution was prepared with the raw material composition shown in Table 1, and the raw material solution was continuously supplied to the first reactor at the flow rate shown in Table 1. The polymerization initiator was added to the raw material solution at the inlet of the first reactor so as to have the addition concentration shown in Table 1 (concentration on a mass basis with respect to the total amount of the raw material styrene and methacrylic acid) and uniformly mixed. Polymerization initiators listed in Table 1 are as follows: 2,2-di(4,4-t-butylperoxycyclohexyl)propane (Pertetra A manufactured by NOF Corporation was used.)
In addition, in the third reactor, a temperature gradient was provided along the direction of flow, and the temperatures in the intermediate portion and the outlet portion were adjusted as shown in Table 1.
Subsequently, the polymer-containing solution continuously taken out from the third reactor was introduced in series into a vacuum devolatilization tank equipped with a preheater composed of two stages. After separating unreacted styrene and ethylbenzene by adjusting the temperature of and adjusting the pressure to the value shown in Table 1, the product is extruded into a strand from a multi-hole die, and the strand is cooled and cut by a cold cut method. pelleted.

(Examples 1-4, Comparative Examples 1-3)
At the contents shown in Table 2, (a) styrene resin PS-1, (b) phosphorus antioxidant/phenolic antioxidant, and (c) anthraquinone compound were mixed in a single screw extruder with a screw diameter of 40 mm. was melted and kneaded at a cylinder temperature of 230° C. and a screw rotation speed of 100 rpm to obtain pellets. The phosphorus antioxidant and phenolic antioxidant (b) used in Table 2 are respectively 2,2′-methylenebis(4,6-di-tert-butyl-1-phenyloxy)(2-ethylhexyloxy ) Phosphorus (adekastab HP-10 manufactured by ADEKA Corporation), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate (Irganox 1076 manufactured by BASF Japan Co., Ltd.), and (c) The anthraquinone compound is Solvent Violet 33 (Blue J manufactured by Mitsubishi Chemical Corporation).

Using the obtained pellets, injection molding was performed at a cylinder temperature of 230° C. and a mold temperature of 50° C. to form a plate-like molded product of 127×127×3 mm thickness. In order to evaluate the long-term thermal stability, the resulting molded article was stored in an oven at 80°C for 1000 hours. In order to evaluate the optical properties of the initial molded product before storage and the molded product after storage, a 115 × 85 × 3 mm thick test piece was cut from the plate-shaped molded product, the end face was polished by buffing, and the end face was mirror-finished. A plate-shaped molded article having For the plate-shaped molded article after polishing, using an ultraviolet-visible spectrophotometer V-670 manufactured by JASCO Corporation, the size of 20 × 1.6 mm, the incident light with a spread angle of 0 °, the wavelength at the optical path length of 115 mm Spectral transmittance from 350 nm to 800 nm was measured.

In Table 2, each evaluation is shown according to the following criteria. X, Δ, ◯, and ⊚ are set, with ⊙ being the worst, ⊙ being the best, and the evaluation being higher in the order of ×, Δ, ◯, and ⊚.

transparency
◎: transmittance of 84% or more ○: transmittance of 82.5% or more and less than 84% △: transmittance of 80% or more and less than 82.5% ×: transmittance of less than 80%

wavelength dependence
◎: 0.98<t580/t480<1.02
○: 0.97 < t580/t480 ≤ 0.98, or 1.02 ≤ t580/t480 < 1.03
△: 0.96 < t580/t480 ≤ 0.97 or 1.03 ≤ t580/t480 < 1.04
×: t580/t480 ≤ 0.96, or t580/t480 ≥ 1.04

uniform surface luminescence
This is an item evaluated by combining two evaluations of transparency and wavelength dependence.
◎: Both transparency and wavelength dependence are ◎
○: Both transparency and wavelength dependence are ○ or more, and at least one is ○
△: Both transparency and wavelength dependence are △ or more, and at least one is △
×: At least one of transparency and wavelength dependence is ×

Long-term uniform surface luminescence
This is an item comprehensively evaluating the initial uniform surface luminescence and the uniform surface luminescence after the long-term thermal stability test (80° C., 1000 hours later).
◎: Initial uniform surface luminescence ◎ and uniform surface luminescence after long-term thermal stability test ○ or more ○: Initial uniform surface luminescence ○ and uniform surface luminescence after long-term thermal stability test △ or more △: Initial uniform surface luminescence △ and uniform surface luminescence after long-term thermal stability test △
×: Initial uniform surface luminescence × or uniform surface luminescence after long-term thermal stability test ×

The molded articles of Examples were excellent in initial uniform surface luminescence and excellent in long-term uniform surface luminescence.

The optical styrene-based resin composition and molded article of the present invention are excellent in initial uniform surface luminescence and long-term uniform surface luminescence. , mobile phones, car navigation systems, and the like.

Claims (2)

(a) a styrene resin, (b) a phosphorus antioxidant and/or a phenolic antioxidant, (c) Disperse Blue 14, Disperse Blue 60, Disperse Blue 197, Disperse Blue 198, Disperse Blue 334, Disperse Blue 72, Solvent Blue 11, Ｓｏｌｖｅｎｔ Ｂｌｕｅ３５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ３６、Ｓｏｌｖｅｎｔ Ｂｌｕｅ４５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ５９、Ｓｏｌｖｅｎｔ Ｂｌｕｅ６３、Ｓｏｌｖｅｎｔ Ｂｌｕｅ６７、Ｓｏｌｖｅｎｔ Ｂｌｕｅ７８、Ｓｏｌｖｅｎｔ Ｂｌｕｅ８３、Ｓｏｌｖｅｎｔ Ｂｌｕｅ８７、Ｓｏｌｖｅｎｔ Ｂｌｕｅ９４、Ｓｏｌｖｅｎｔ Ｂｌｕｅ９５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ９７、Ｓｏｌｖｅｎｔ Ｂｌｕｅ１０４、Ｓｏｌｖｅｎｔ Ｂｌｕｅ１０５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ１２２、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ１３、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３３ 、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３４、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ１４、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３１、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３６、Ｓｏｌｖｅｎｔ Ｖｉｏｌｅｔ３７、Ｄｉｓｐｅｒｓｅ Ｖｉｏｌｅｔ２６、Ｄｉｓｐｅｒｓｅ Ｖｉｏｌｅｔ２８、Ｄｉｓｐｅｒｓｅ Ｖｉｏｌｅｔ３１、Ｄｉｓｐｅｒｓｅ Ｖｉｏｌｅｔ５７、Ｓｏｌｖｅｎｔ Ｇｒｅｅｎ３、Ｓｏｌｖｅｎｔ Ｇｒｅｅｎ２０、Ｓｏｌｖｅｎｔ Ｇｒｅｅｎ２８から選ばれた1種類以上のアントラキノン系化合物を含み、
The content of (b) in 100% by mass of the styrene resin composition is 0.02 to 1% by mass,
A styrenic resin composition for optics, wherein the content of (c) with respect to the total mass of the resin component is 1 to 70 ppb. An optical component comprising the optical styrene resin composition according to claim 1 .