Aromatic polycarbonate resin composition and light-diffusing molded article

Abstract

To provide an aromatic polycarbonate resin composition which is excellent in thermal stability, has high transparency, light transmittance and light diffusibility, and hardly causes deterioration in transparency and light transmittance without impairing characteristics such as heat resistance and mechanical strength which a polycarbonate resin originally has.SOLUTION: An aromatic polycarbonate resin composition containing a linear aromatic polycarbonate resin (A), a polyether derivative (B), a light diffusing agent (C), a phosphorus-based antioxidant (D), and a specific hindered phenol-based aromatic compound (E), wherein the aromatic polycarbonate resin composition contains 0.1 to 2.0 parts by weight of the polyether derivative (B), 0.1 to 6.0 parts by weight of the light diffusing agent (C), up to 0.5 parts by weight of the phosphorus-based antioxidant (D), and up to 0.003 parts by weight of the specific hindered phenol-based aromatic compound (E) with respect to 100 parts by weight of the linear aromatic polycarbonate resin (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aromatic polycarbonate resin composition and a light-diffusing molded article. [Background technology]

[0002] Polycarbonate resins have excellent impact resistance, heat resistance, transparency, etc., and have therefore conventionally been used in molded articles such as light guide plates, various lenses, and nameplates. Light-diffusing molded articles made from resin compositions in which an aromatic polycarbonate resin is blended with a light-diffusing agent such as inorganic fine particles or polymer fine particles have superior heat resistance and dimensional stability compared to light-diffusing molded articles made from acrylic resins, and are therefore used in a wide range of fields, such as light lamp covers, meters, signs (especially internally illuminated signs), plastic window glass, light diffusers for image readers or image display devices (e.g., light diffusers used in backlight modules of liquid crystal display devices and light diffusers used in projection display screens of projector televisions), and light diffuser films (e.g., highly transmittant light diffuser films used to improve the brightness of liquid crystal display devices).

[0003] In recent years, image display devices have become larger, thinner (lighter), more complex in shape, and have higher performance. As a result, there is an increasing demand for light-diffusing molded products, particularly light-diffusing plates and light-diffusing films used in image display devices, to be larger, thinner (lighter), more complex in shape, and have higher performance, and there is a demand for aromatic polycarbonate-based resin compositions that have excellent fluidity during molding.

[0004] Patent Document 1 describes that fluidity is improved by adding a pentaerythritol-based ester compound to an aromatic polycarbonate-based resin to lower its molecular weight through transesterification. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2013 / 011977 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the polycarbonate resin composition disclosed in Patent Document 1 does not fully satisfy recent demands for materials, such as minimal decrease in transparency and light transmittance even when molded at high temperatures to form thin-walled products, and the ability to be made large.

[0007] Furthermore, in recent years, there has been a growing demand for light-diffusing molded articles (e.g., light diffusion plates for image display devices) used in thin molded in-vehicle image display devices with a thickness of approximately 0.3 mm that do not lose much transparency or light transmittance even when exposed to high-temperature conditions such as light irradiation for an extremely long period of time. In other words, there is a growing demand for materials with high light-diffusing properties that do not lose light transmittance even when large, yet do not allow the light source to be seen through them.

[0008] The present invention aims to provide an aromatic polycarbonate resin composition that does not impair the inherent properties of polycarbonate resin, such as heat resistance and mechanical strength, and that has excellent thermal stability and high transparency, light transmittance, and light diffusion properties, and that is resistant to deterioration in transparency and light transmittance (resistant to clouding and coloration) even when molded into a large, thin molded product of about 0.3 mm (e.g., a light diffusion plate for an image display device) and exposed to high temperature conditions such as light irradiation for an extremely long period of time; in other words, it does not reduce light transmittance even when molded into a large product, and yet has high light diffusion properties that prevent light sources from being seen through the product. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems, and as a result have found that an aromatic polycarbonate resin composition containing a linear aromatic polycarbonate resin, a polyether derivative (B), and a light diffusing agent (C) in predetermined amounts has excellent thermal stability and high light transmittance without impairing the inherent properties of polycarbonate resins, such as heat resistance and mechanical strength, and further has found that even when a thin molded product (light guide plate) having a thickness of about 0.3 mm is exposed to high temperature conditions such as irradiation with a light source for a long period of time, the transparency and transmittance are less likely to decrease (opacity or coloration is less likely to occur), thereby completing the present invention.

[0010] Specifically, the present invention provides an aromatic polycarbonate resin composition containing a linear aromatic polycarbonate resin (A), a polyether derivative (B), a light diffusing agent (C), a phosphorus-based antioxidant (D), and an aromatic compound (E) represented by the following formula (1), wherein the aromatic polycarbonate resin composition contains 0.1 to 2.0 parts by weight of the polyether derivative (B), 0.1 to 6.0 parts by weight of the light diffusing agent (C), up to 0.5 part by weight of the phosphorus-based antioxidant (D), and up to 0.003 part by weight of the aromatic compound (E) relative to 100 parts by weight of the linear aromatic polycarbonate resin (A), and a light-diffusing molded article obtained by molding the aromatic polycarbonate resin composition. Formula (1): [ka] [Effects of the Invention]

[0011] The polycarbonate resin composition of the present invention does not impair the inherent properties of polycarbonate resins, such as heat resistance and mechanical strength, and has excellent thermal stability, high transparency, light transmittance, and light diffusion properties. Furthermore, the resulting molded article is resistant to deterioration in transparency and transmittance (is resistant to clouding or coloring) even when exposed to high temperatures for long periods under hot sunlight and / or light source irradiation. Therefore, even a thin molded article (diffusion plate) with a thickness of, for example, about 0.3 mm, is resistant to changes in hue and deterioration in appearance (deterioration), and is resistant to deterioration in transparency (is resistant to clouding or coloring) even when exposed to high temperatures for long periods under external environments or light source conditions. In other words, a polycarbonate resin composition can be provided that maintains light transmittance and yet has high light diffusion properties that prevent light sources from being seen through it, making it highly valuable for industrial use. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described in detail. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of well-known matters or redundant explanation of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0013] The inventors provide the following explanation to enable those skilled in the art to fully understand the present invention, and it is not intended to limit the subject matter described in the claims.

[0014] The aromatic polycarbonate resin composition according to an embodiment of the present invention contains a linear aromatic polycarbonate resin (A), a polyether derivative (B), a light diffusing agent (C), and, if necessary, a phosphorus-based antioxidant (D) and / or a specific aromatic compound (E). The aromatic polycarbonate resin composition according to the embodiment may further contain an epoxy compound and / or other components, if necessary.

[0015] In the embodiments of the present invention, the "linear aromatic polycarbonate resin (A)" is a polycarbonate resin based on an aromatic compound and is not particularly limited as long as it can produce the aromatic polycarbonate resin composition of the present invention. However, branched aromatic polycarbonates are excluded from the scope of the present invention as much as possible because they reduce transparency and light transmittance. Examples of linear aromatic polycarbonate resins include polymers obtained by the phosgene method, in which various dihydroxydiaryl compounds are reacted with phosgene, or the transesterification method, in which a dihydroxydiaryl compound is reacted with a carbonate ester such as diphenyl carbonate. A typical example includes a polycarbonate resin produced from 2,2-bis(4-hydroxyphenyl)propane (bisphenol A).

[0016] Examples of the dihydroxydiaryl compound include, in addition to bisphenol A, bis(hydroxyaryl)alkanes such as bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxyphenyl-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane; Examples of suitable hydroxyaryl compounds include bis(hydroxyaryl)cycloalkanes such as bis(4-hydroxyphenyl)cyclopentane and 1,1-bis(4-hydroxyphenyl)cyclohexane; dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether; dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide; dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; and dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone. These compounds can be used alone or in combination. Other compounds that can be used in combination include piperazine, dipiperidyl hydroquinone, resorcinol, and 4,4'-dihydroxydiphenyl.

[0017] The viscosity average molecular weight of the linear aromatic polycarbonate resin (A) is preferably 10,000 to 100,000, and more preferably 12,000 to 30,000. When producing such an aromatic polycarbonate resin (A), a molecular weight modifier, a catalyst, etc. may be used as needed.

[0018] In the embodiment of the present invention, the polyether derivative (B) is a derivative of a polyether compound and is not particularly limited as long as it can provide the aromatic polycarbonate resin composition of the present invention. Representative examples of such polyether derivatives include polyether derivatives represented by the following formula (2):

[0019] Formula (2): RO-(XO)m(YO)n-R' (In the formula, R and R' each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, X represents a linear or branched alkylene group having 2 to 4 carbon atoms, Y represents a linear or branched alkylene group having 2 to 5 carbon atoms, X and Y may be the same or different, m and n each independently represent 3 to 60, and m+n represents 6 to 120.) The weight-average molecular weight of the polyether derivative represented by formula (2) is preferably 500 to 8000, and more preferably 1000 to 4000. As the polyether derivative represented by formula (2), commercially available products can be used.

[0020] The polyether derivative represented by formula (2) may be a compound represented by the following formula (2-1). Formula (2-1): RO-(XO)m(YO)n-R' (In the formula, R and R' each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, X represents a linear alkylene group having 2 to 4 carbon atoms, Y represents a branched alkylene group having 2 to 5 carbon atoms, m and n each independently represent a number from 3 to 60, and m+n represents a number from 8 to 90.) The weight average molecular weight of the polyether derivative represented by formula (2-1) is preferably 500 to 8000, more preferably 1000 to 4000. As the polyether derivative represented by formula (2-1), commercially available products can be used.

[0021] The polyether derivative represented by formula (2) may be a compound represented by the following formula (2-2). Formula (2-2): RO-(XO)m(YO)n-R' (In the formula, R and R' each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, X represents a linear alkylene group having 2 to 4 carbon atoms, Y represents a linear alkylene group having 2 to 5 carbon atoms, X and Y may be the same or different, m and n each independently represent a number from 3 to 60, and m+n represents a number from 6 to 100.) The weight average molecular weight of the polyether derivative represented by formula (2-2) is preferably 500 to 8000, more preferably 1000 to 4000. As the polyether derivative represented by formula (2-2), commercially available products can be used.

[0022] The polyether derivative represented by formula (2) may be a compound represented by the following formula (2-3). Formula (2-3): RO-(XO)m(YO)n-R' (In the formula, R and R' each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, X represents a branched alkylene group having 2 to 4 carbon atoms, Y represents a branched alkylene group having 2 to 5 carbon atoms, X and Y may be the same or different, m and n each independently represent a number from 3 to 60, and m+n represents a number from 6 to 120.) The weight average molecular weight of the polyether derivative represented by formula (2-3) is preferably 500 to 8000, more preferably 1000 to 4000. As the polyether derivative represented by formula (2-3), commercially available products can be used.

[0023] The polyether derivative represented by formula (2) preferably includes at least one selected from the group consisting of polyether derivatives represented by the following formula (3), polyether derivatives represented by formula (4), polyether derivatives represented by formula (5), polyether derivatives represented by formula (6), polyether derivatives represented by formula (7), polyether derivatives represented by formula (8), polyether derivatives represented by formula (9), polyether derivatives represented by formula (10), and polyether derivatives represented by formula (11).

[0024] The polyether derivative represented by formula (2-1) preferably includes at least one selected from the group consisting of polyether derivatives represented by the following formula (3), polyether derivatives represented by formula (4), polyether derivatives represented by formula (5), polyether derivatives represented by formula (6), and polyether derivatives represented by formula (7).

[0025] The polyether derivative represented by formula (2-2) preferably includes at least one selected from the group consisting of polyether derivatives represented by formula (8) and polyether derivatives represented by formula (9).

[0026] The polyether derivative represented by formula (2-3) preferably includes at least one selected from the group consisting of polyether derivatives represented by formula (10) and polyether derivatives represented by formula (11).

[0027] Formula (3): HO-(CH2CH2CH2CH2O)m(CH(CH3)CH2O)nH (In the formula, m and n each independently represent 3 to 60, and m+n represents 8 to 90.)

[0028] The polyether derivative represented by formula (3) is preferably a modified glycol containing a tetramethylene glycol unit and a propylene glycol unit. Commercially available polyether derivatives can be used, such as NOF Corp.'s Polyserine DCB-1000 (weight average molecular weight 1000), Polyserine DCB-2000 (weight average molecular weight 2000), and Polyserine DCB-4000 (weight average molecular weight 4000). The weight average molecular weight of the polyether derivative represented by formula (3) is preferably 500 to 8000, more preferably 1000 to 4000.

[0029] Formula (4): HO-(CH2CH2CH2CH2O)m(CH2CH2CH(CH3)CH2O)nH (In the formula, m and n each independently represent 3 to 60, and m+n represents 8 to 90.)

[0030] The polyether derivative represented by formula (4) is preferably a modified glycol containing a tetramethylene glycol unit and a 2-methyltetramethylene glycol unit. Commercially available polyether derivatives can be used, such as PTG-L1000 (weight average molecular weight: 1000), PTG-L2000 (weight average molecular weight: 2000), or PTG-L3000 (weight average molecular weight: 3000) manufactured by Hodogaya Chemical Co., Ltd. The weight average molecular weight of the polyether derivative represented by formula (4) is preferably 500 to 8000, more preferably 1000 to 4000.

[0031] Formula (5): HO-(CH2CH2O)m(CH(CH3)CH2O)nH (In the formula, m and n each independently represent 3 to 60, and m+n represents 8 to 90.)

[0032] The polyether derivative represented by formula (5) is preferably a modified glycol containing an ethylene glycol unit and a propylene glycol unit. Commercially available products such as Unilube 50DE-25 (weight average molecular weight 1750) and Unilube 75DE-25 (weight average molecular weight 1400), manufactured by NOF Corporation, can be used. The weight average molecular weight of the polyether derivative represented by formula (5) is preferably 500 to 8000, more preferably 1000 to 4000.

[0033] Formula (6): RO-(CH2CH2CH2CH2O)m(CH(CH3)CH2O)nH (In the formula, R represents an alkyl group having 1 to 30 carbon atoms, m and n each independently represent 3 to 60, and m+n represents 8 to 90.)

[0034] The polyether derivative represented by formula (6) is preferably a modified glycol containing a tetramethylene glycol unit and a propylene glycol unit and having a butyl group or a stearyl group at one end. Commercially available polyether derivatives are available, such as NOF Corp.'s Polyserine BC-1000 (butyl group at one end, weight-average molecular weight 1000) and Polyserine SC-1000 (stearyl group at one end, weight-average molecular weight 1000). The weight-average molecular weight of the polyether derivative represented by formula (6) is preferably 500 to 8000, more preferably 1000 to 4000.

[0035] Formula (7): RO-(CH2CH2O)m(CH(CH3)CH2O)nH (In the formula, R represents an alkyl group having 1 to 30 carbon atoms, m and n each independently represent 3 to 60, and m+n represents 8 to 90.)

[0036] The polyether derivative represented by formula (7) is preferably a modified glycol containing an ethylene glycol unit and a propylene glycol unit and having a butyl or stearyl group at one end. Commercially available polyether derivatives include NOF Corp.'s Unilube 50MB-11 (butyl group at one end, weight-average molecular weight 1000), Unilube 50MB-26 (butyl group at one end, weight-average molecular weight 2000), Unilube 50MB-72 (butyl group at one end, weight-average molecular weight 3000), and Unilube 10MS-250KB (stearyl group at one end, weight-average molecular weight 2000). The weight-average molecular weight of the polyether derivative represented by formula (7) is preferably 500 to 8000, more preferably 1000 to 4000.

[0037] Formula (8): HO-(CH2CH2CH2CH2O)m(CH2CH2O)nH (In the formula, m and n each independently represent 3 to 60, and m+n represents 8 to 90.)

[0038] The polyether derivative represented by formula (8) is preferably a modified glycol containing a tetramethylene glycol unit and an ethylene glycol unit. Commercially available polyether derivatives can be used, such as NOF Corp.'s Polyserine DC3000E (weight average molecular weight 3000) and Polyserine DC1800E (weight average molecular weight 1800). The weight average molecular weight of the polyether derivative represented by formula (8) is preferably 500 to 8000, more preferably 1000 to 4000.

[0039] Formula (9): HO-(CH2CH2CH2CH2O)pH (In the formula, p represents 6 to 100.)

[0040] The polyether derivative represented by formula (9) is preferably polytetramethylene glycol. Commercially available polyether derivatives are available, such as PTG-650SN (weight average molecular weight 650), PTG-850SN (weight average molecular weight 850), PTG-1000SN (weight average molecular weight 1000), PTG-1400SN (weight average molecular weight 1400), PTG-2000SN (weight average molecular weight 2000), and PTG-2900 (weight average molecular weight 2900), all manufactured by Hodogaya Chemical Co., Ltd. The weight average molecular weight of the polyether derivative (polytetramethylene glycol) represented by formula (9) is preferably 500 to 8000, more preferably 1000 to 4000.

[0041] Equation (10): Formula: HO-(CH(CH3)CH2O)qH (In the formula, q represents 7 to 120.)

[0042] Polypropylene glycol is preferred as the polyether derivative represented by formula (10). Commercially available polyether derivatives can be used, such as Polyglycol P2000P (weight average molecular weight 2000) manufactured by Dow Chemical, Uniol D-1000 (weight average molecular weight 1000), Uniol D-2000 (weight average molecular weight 2000), and Uniol D-4000 (weight average molecular weight 4000) manufactured by NOF Corporation. The weight average molecular weight of the polyether derivative (polypropylene glycol) represented by formula (10) is preferably 500 to 8000, more preferably 1000 to 4000.

[0043] Equation (11): HO-(CH(C2H5)CH2O)rH (In the formula, r represents 6 to 100.)

[0044] Polybutylene glycol is preferred as the polyether derivative represented by formula (11). Commercially available products of this polyether derivative can be used, such as Uniol PB-500 (weight average molecular weight 500), Uniol PB-1000 (weight average molecular weight 1000), and Uniol PB-2000 (weight average molecular weight 2000), all manufactured by NOF Corporation. The weight average molecular weight of the polyether derivative (polybutylene glycol) represented by formula (11) is preferably 500 to 8000, more preferably 1000 to 4000.

[0045] The polyether derivatives represented by the general formula (2) generally have high heat resistance, and molded articles obtained by molding aromatic polycarbonate resin compositions containing such polyether derivatives at high temperatures have high brightness and light transmittance.

[0046] Each of the polyether derivatives represented by the formulas (2) to (11) may contain repeating units other than those described in each formula, as long as the aromatic polycarbonate resin composition and optical molded article targeted by the present invention can be obtained. Examples of such repeating units include repeating units based on impurities that may be contained in the starting materials for the polyether derivative, and repeating units based on the initiator (polymerization initiator) used during polymerization.

[0047] When a polymerization initiator is used in synthesizing the polyether derivative, examples of the polymerization initiator include the following compounds: hydrogenated bisphenol A, bisphenol A, isosorbide, glycerin, pentaerythritol, sorbitol, glucose, etc.

[0048] As a polyether derivative containing a repeating unit based on such a polymerization initiator, for example, Polyserine 60DB-2000H (manufactured by NOF Corporation) represented by the following formula (3') can also be used (see formula 3-2). Formula (3'): [ka] (In the formula, m1+m2 corresponds to m in formula (3), and n1+n2 corresponds to n in formula (3).)

[0049] The weight average molecular weight of the polyether derivative represented by formula (3-2) is preferably 500 to 8,000, and more preferably 1,000 to 4,000.

[0050] Furthermore, the polyether derivative (B) used in the present invention has a moderate lipophilicity and therefore has excellent compatibility with the aromatic polycarbonate resin (A), so that the transparency of a molded article obtained from an aromatic polycarbonate resin composition containing the polyether derivative (B) can be maintained without being reduced. The weight-average molecular weight of such a polyether derivative (B) is preferably 500 to 8,000, more preferably 1,000 to 4,000.

[0051] Furthermore, the CPR (unit: dimensionless) (Controlled Polymerization Rate: an index showing the amount of basic substances in a polyether derivative; measured in accordance with JIS K1557-4) of the polyether derivative (B) used in the present invention is preferably 2.0 or less, more preferably 1.0 or less. When the CPR is 2.0 or less, the polyether derivative (B) has excellent compatibility with polycarbonate resins, is inhibited from decomposition and deterioration, has excellent storage stability, and is less likely to adversely affect the hue of the resulting polycarbonate resin composition. For example, the CPR of polyserine DCB-2000, which corresponds to the polyether derivative (B) represented by the above formula (3), is less than 1.0; the CPR of polyserine 60DB-2000H (manufactured by NOF Corporation), which corresponds to the polyether derivative (B) represented by the above formula (3), is less than 1.0; and the CPR of PTG-1000SN (manufactured by Hodogaya Chemical Co., Ltd.), which corresponds to the polyether derivative (B) represented by the above formula (9), is less than 1.0.

[0052] Furthermore, the pH (measured in accordance with JIS K1557-5) of the polyether derivative (B) used in the present invention is preferably 5.0 or more and less than 7.5, more preferably 6.0 or more and less than 7.0. When the pH of the polyether derivative (B) is 5.0 or more and less than 7.5, decomposition and deterioration are suppressed, resulting in excellent storage stability and less adverse effects on the color of the resulting polycarbonate resin composition. For example, the pH of Polyserine DCB-2000, which corresponds to the polyether derivative (B) represented by the above formula (3), is 6.7; the pH of Polyserine 60DB-2000H (manufactured by NOF Corporation), which corresponds to the polyether derivative (B) represented by the above formula (3), is 6.8; and the pH of PTG-1000SN (manufactured by Hodogaya Chemical Co., Ltd.), which corresponds to the polyether derivative (B) represented by the above formula (9), is 6.7.

[0053] Furthermore, the temperature at which the polyether derivative (B) used in the present invention reduces to 90% by weight (or the temperature at which the weight loss rate is 10%) (measured by thermogravimetry in accordance with JIS K7120) is preferably 300°C or higher, more preferably 330°C or higher. When the temperature at which the polyether derivative (B) reduces to 90% by weight is 300°C or higher, decomposition and deterioration are suppressed, resulting in excellent storage stability and less adverse effects on the color of the resulting polycarbonate resin composition. For example, the temperature at which Polyserine DCB-2000, which corresponds to the polyether derivative (B) represented by the above formula (3), reduces to 90% by weight is 330°C, and the temperature at which Polyserine 60DB-2000H (manufactured by NOF Corporation), which corresponds to the polyether derivative (B) represented by the above formula (3), reduces to 90% by weight is 400°C.

[0054] The amount of the polyether derivative is 0.1 to 2.0 parts by weight, preferably 0.3 to 1.8 parts by weight, based on 100 parts by weight of the aromatic polycarbonate resin (A). If the amount of the polyether derivative is less than 0.1 part by weight, the effects of improving light transmittance and color may be insufficient. Conversely, if the amount of the polyether derivative is more than 2.0 parts by weight, the degree of haze may increase and the light transmittance may decrease.

[0055] In an embodiment of the present invention, the light diffusing agent (C) is not particularly limited as long as it can scatter light inside the polycarbonate resin composition, and there are no particular limitations on its chemical composition, such as whether it is a polymeric or inorganic type. However, when the light diffusing agent (C) is added to the linear polycarbonate resin (A) and dispersed by a known method such as melt mixing using an extruder, it is necessary that the light diffusing agent is incompatible or poorly compatible with the matrix phase and exists as particles.

[0056] As the light diffusing agent (C), fine particles having light diffusing ability are preferred. Examples of such fine particles include inorganic fine particles and polymer fine particles. Examples of inorganic fine particles include glass fillers, calcium carbonate, barium sulfate, silica, talc, mica, wollastonite, titanium oxide, etc. Among these, calcium carbonate is preferred. The shape of the inorganic fine particles is preferably granular (including irregular) or plate-like rather than fibrous. For example, in the case of glass fillers, examples include glass beads, glass balloons, glass milled fibers, glass flakes, ultrathin glass flakes (manufactured by the sol-gel method), and irregular glass. Similarly, various shapes can be used for other inorganic fine particles.

[0057] From the viewpoint of light diffusion, spherical polymeric particles are preferred, with the closer to spherical shape being more preferable. Examples include organic diffusing agents such as silicone-based light diffusing agents, acrylic-based light diffusing agents, silicone rubber-like elastomers, polymethylsilsesquioxane, acrylic-based, styrene-based, polyester-based, polyolefin-based, urethane-based, nylon-based, styrene-(meth)acrylate-based, fluorine-based, norbornene-based, and silicone-based, with silicone-based and acrylic-based light diffusing agents being particularly preferred. Commercially available light diffusing agents can be used. For example, silicone-based light diffusing agents include "Tospearl (registered trademark) 120S" manufactured by Momentive Performance Materials Japan, and acrylic-based light diffusing agents include "Ganzpearl (registered trademark) GM-0449S" and "Ganzpearl GM-0205S" manufactured by Aica Kogyo Co., Ltd., and "Chemisnow (registered trademark) KMR-3TA" manufactured by Soken Chemical & Engineering Co., Ltd.

[0058] As the light diffusing agent (C), fine particles obtained by copolymerizing a styrene monomer, a methyl methacrylate monomer, and a crosslinking agent (styrene-methyl methacrylate copolymer crosslinked fine particles) can also be suitably used. They can be obtained using common methods such as emulsion polymerization, solution polymerization, dispersion polymerization, suspension polymerization, bulk polymerization, soap-free polymerization, and seed polymerization. Among these polymerization methods, emulsion polymerization, dispersion polymerization, and suspension polymerization are preferred, and emulsion polymerization and dispersion polymerization are particularly preferred in terms of the physical properties of the light diffusing plate.

[0059] The crosslinking agent used in the styrene-methyl methacrylate copolymer crosslinked microparticles may be any radically polymerizable monomer containing two or more vinyl groups or (meth)acryloyl groups. Specific examples include divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, and pentaerythritol tetramethacrylate. These crosslinking agents may be used alone or in combination.

[0060] The average particle size of the styrene-methyl methacrylate copolymer crosslinked microparticles is 5 to 30 μm. A more preferred average particle size is in the range of 8 to 20 μm. If the average particle size is less than 5 μm, the surface of the resulting light diffusion plate will remain smooth, resulting in insufficient light scattering and poor light diffusion. On the other hand, if the average particle size exceeds 30 μm, the surface of the resulting light diffusion plate will become too smooth, causing light to travel straight through and transmit, resulting in reduced light scattering and poor light diffusion and light source transmission prevention, which are undesirable. Common methods for measuring the average particle size of microparticles include the Coulter method, dynamic light scattering, and centrifugal sedimentation.

[0061] The refractive index of the styrene-methyl methacrylate copolymer crosslinked fine particles is in the range of 1.54 to 1.57. A more preferable range is 1.55 to 1.57. If the refractive index is less than 1.54, haze may occur, resulting in reduced light transmittance. If the refractive index exceeds 1.57, light diffusibility may decrease. The refractive index can be changed by adjusting the polymerization ratio of the styrene and methyl methacrylate monomers when copolymerizing the fine particles.

[0062] Commercially available styrene-methyl methacrylate copolymer crosslinked microparticles include, for example, SMX-12R (average particle size 12.3 μm, refractive index 1.56) manufactured by Sekisui Chemical Co., Ltd., and GMS-6121 (average particle size 11.3 μm, refractive index 1.56) manufactured by Guide Win Special Chemicals.

[0063] The Becke method is a common method for measuring the refractive index of styrene-methyl methacrylate copolymer crosslinked microparticles. Resin particles are placed on a glass slide and a refractive index liquid (Cargill Standard Refractive Index Liquid, manufactured by Cargill) is dropped onto it. The resin particles and refractive index liquid are mixed thoroughly, and a sodium lamp is irradiated from below. The particle outline is observed from above. If the outline is not visible, the refractive index of the refractive index liquid and the resin particles is deemed to be equal. The absolute value of the difference between the refractive index of the light diffusing agent and the refractive index of the aromatic polycarbonate resin is preferably 0.02 to 0.2. A refractive index difference within this range enables both light diffusibility and total light transmittance to be achieved at a high level. The refractive index of the light diffusing agent is more preferably lower than the refractive index of the aromatic polycarbonate resin.

[0064] The preferred average particle size of the light diffusing agent is 0.1 to 50 μm, more preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. If the average particle size of the light diffusing agent is too small, sufficient light dispersion effect cannot be obtained, while if it is too large, the surface of the molded article may become rough and the mechanical strength of the molded article may decrease. Here, the average particle size of the light diffusing agent refers to the volume average particle size measured by the Coulter counter method. The Coulter counter method quantifies particle size by passing an electrolyte containing suspended sample particles through an aperture and reading the change in voltage pulse generated in proportion to the particle volume. Furthermore, the voltage pulse height can be measured one by one to obtain a volume distribution histogram of the sample particles. Measurement of particle size or particle size distribution using the Coulter counter method is the most widely used particle size distribution measuring device.

[0065] From the viewpoint of light diffusibility, the light diffusing agent (C) preferably has a refractive index difference (Δn) of 0.01 or more with respect to the polycarbonate resin (A). In order to fully exhibit light diffusibility and suppress problems such as a light source behind the molded product (such as a light diffusion plate) being visible through the molded product, and to further exhibit sufficient brightness, the light diffusing agent preferably has a refractive index difference of 0.05 or more with respect to the polycarbonate resin, and particularly preferably 0.07 or more.

[0066] The mass average particle size of the light diffusing agent (C) is usually 0.5 μm or more, preferably 1 μm or more, and more preferably 1.5 μm or more, and usually 30 μm or less, preferably 20 μm or less, more preferably 10 μm or less, even more preferably 5 μm or less, and particularly preferably 3 μm or less. If the mass average particle size is too small, the light diffusing properties of the resulting polycarbonate resin composition will be poor, and when used as a diffusion plate or the like, the light source will tend to be visible through or visibility will be poor. Conversely, if the mass average particle size is too large, the diffusing effect relative to the content may be low.

[0067] The light diffusing agent (C) may be used alone or in any combination and ratio of two or more kinds. It is preferable to use a silicone-based light diffusing agent in combination with other light diffusing agents.

[0068] Any of silicone-based light diffusing agents, acrylic-based light diffusing agents, and styrene-methyl methacrylate copolymer crosslinked microparticles may be used in combination with an inorganic light diffusing agent (inorganic microparticles). When any of silicone-based light diffusing agents, acrylic-based light diffusing agents, and styrene-methyl methacrylate copolymer crosslinked microparticles is used in combination with an inorganic light diffusing agent, the amount of silicone-based or organic diffusing agent can be reduced while still achieving the same light diffusing properties as before the reduction. Titanium oxide (white pigment) is preferred as the inorganic light diffusing agent to be used in combination. Examples of titanium oxide that can be used include TIPAQUE (registered trademark) PC-3 manufactured by Ishihara Sangyo Kaisha, Ltd., CP-K manufactured by Resinocolor Kogyo Co., Ltd., and KRONOS (registered trademark) 2233 manufactured by Kronos.

[0069] The amount of the light diffusing agent (C) is The amount is preferably 0.1 to 6.0 parts by weight, more preferably 1.0 to 5.0 parts by weight, relative to 100 parts by weight of the aromatic polycarbonate resin (A). If the amount is less than 0.1 part by weight, light is not sufficiently scattered, resulting in a poor effect in preventing the visibility of the light source, while if the amount exceeds 6.0 parts by weight, the transmittance may be significantly reduced.

[0070] The aromatic polycarbonate resin composition according to an embodiment of the present invention may contain a phosphorus-based antioxidant (D) as needed. When the aromatic polycarbonate resin composition simultaneously contains the polyether derivative (B), the diffusing agent (C), and the phosphorus-based antioxidant (D), it is possible to maintain and improve the excellent optical properties required for a light-diffusing molded article, and in particular to prevent deterioration of the initial optical properties of a molded article made from the resulting aromatic polycarbonate resin composition, and further to prevent deterioration due to usage conditions.

[0071] The phosphorus-based antioxidant (D) is not particularly limited as long as it can produce the aromatic polycarbonate resin composition intended by the present invention, but it preferably contains a phosphite ester compound having the following phosphite ester structure: [ka]

[0072] In the aromatic polycarbonate resin composition according to an embodiment of the present invention, the phosphorus-based antioxidant (D) preferably contains at least one compound selected from the group consisting of a phosphite ester compound represented by the following formula (12), a phosphite ester compound represented by the following formula (13), a phosphite ester compound represented by the following formula (14), and a phosphite ester compound represented by the following formula (15):

[0073] The phosphorus-based antioxidant (D) preferably contains, for example, a compound represented by the following formula (12).

[0074] Formula (12): [ka] (In the formula, R 1 represents an alkyl group having 1 to 20 carbon atoms, and a represents an integer of 0 to 3.

[0075] In the formula (12), R 1 is an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms.

[0076] Examples of the compound represented by formula (12) include triphenyl phosphite, tricresyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, trisnonylphenyl phosphite, etc. Among these, tris(2,4-di-t-butylphenyl) phosphite is particularly suitable, and is commercially available, for example, as Irgafos 168 manufactured by BASF ("Irgafos" is a registered trademark of BASF Societas Europea).

[0077] The phosphorus-based antioxidant (D) preferably contains, for example, a compound represented by the following formula (13).

[0078] Equation (13): [ka] (In the formula, R 2 , R 3 , R 5 and R 6 R each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group. 4 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; X represents a single bond, a sulfur atom, or a group of the formula: -CHR 7 -(where R 7 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. A represents an alkylene group having 1 to 8 carbon atoms or a group represented by the formula: *-COR 8 -(where R 8 represents a single bond or an alkylene group having 1 to 8 carbon atoms, and * represents a bond on the oxygen side. Either Y or Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

[0079] In equation (13), R 2 , R 3 , R 5 and R 6 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group.

[0080] Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, t-pentyl, i-octyl, t-octyl, and 2-ethylhexyl groups. Examples of cycloalkyl groups having 5 to 8 carbon atoms include cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of alkylcycloalkyl groups having 6 to 12 carbon atoms include 1-methylcyclopentyl, 1-methylcyclohexyl, and 1-methyl-4-i-propylcyclohexyl groups. Examples of aralkyl groups having 7 to 12 carbon atoms include benzyl, α-methylbenzyl, and α,α-dimethylbenzyl groups.

[0081] R 2 , R 3 and R 5 are preferably each independently an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an alkylcycloalkyl group having 6 to 12 carbon atoms. 2 and R 5 are each preferably independently a t-alkyl group such as a t-butyl group, a t-pentyl group, or a t-octyl group, a cyclohexyl group, or a 1-methylcyclohexyl group. 3 is preferably an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, or a t-pentyl group, and more preferably a methyl group, a t-butyl group, or a t-pentyl group.

[0082] R 6 is preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms, and more preferably a hydrogen atom, or an alkyl group having 1 to 5 carbon atoms such as a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, or t-pentyl group.

[0083] In equation (13), R4 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 In particular, the alkyl groups exemplified in the explanation of R 4 is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom or a methyl group.

[0084] In formula (13), X represents a single bond, a sulfur atom, or a group represented by the formula: -CHR 7 -, where the formula is -CHR 7 -R in 7 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms and the cycloalkyl group having 5 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 Examples of the alkyl and cycloalkyl groups include those exemplified in the description of 1. In particular, X is preferably a single bond, a methylene group, or a methylene group substituted with a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, or the like, and more preferably a single bond.

[0085] In formula (13), A is an alkylene group having 1 to 8 carbon atoms or a group represented by the formula: *-COR 8 - represents a group represented by the formula: *-COR. Examples of the alkylene group having 1 to 8 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, and a 2,2-dimethyl-1,3-propylene group, and the like, with a propylene group being preferred. 8 -R in 8 represents a single bond or an alkylene group having 1 to 8 carbon atoms. 8 Examples of the alkylene group having 1 to 8 carbon atoms represented by R include the alkylene groups exemplified in the description of A. 8is preferably a single bond or an ethylene group. 8 The * in - indicates a bond on the oxygen base side, and indicates that the carbonyl group is bonded to the oxygen atom of the phosphite group.

[0086] In formula (13), one of Y and Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkoxy group having 1 to 8 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a t-butoxy group, and a pentyloxy group. Examples of the aralkyloxy group having 7 to 12 carbon atoms include a benzyloxy group, an α-methylbenzyloxy group, and an α,α-dimethylbenzyloxy group. Examples of the alkyl group having 1 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 Examples of the alkyl groups include those exemplified in the explanation of 1.

[0087] Examples of the compound represented by formula (13) include 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepine, Examples include 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, and the like. Among these, when the resulting aromatic polycarbonate resin composition is to be used in a field where optical properties are particularly required, 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine is suitable, and is commercially available, for example, as Sumilizer GP ("Sumilizer" is a registered trademark) manufactured by Sumitomo Chemical Co., Ltd.

[0088] The phosphorus-based antioxidant (D) preferably contains, for example, a compound represented by the following formula (14).

[0089] Equation (14): [ka] (In the formula, R 9 and R 10 each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and b and c each independently represent an integer of 0 to 3.

[0090] Examples of the compound represented by formula (14) include bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite and phenylbisphenol A pentaerythritol diphosphite. Bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite is commercially available under the trade name "ADK STAB PEP-24G" manufactured by ADEKA Corporation. ADK STAB PEP-36 ("ADK STAB" is a registered trademark) manufactured by ADEKA Corporation is also commercially available.

[0091] The phosphorus-based antioxidant (D) preferably contains, for example, a compound represented by the following formula (15).

[0092] Formula (15): [ka]

[0093] (In the formula, R 11 ~R 18 R each independently represents an alkyl group or alkenyl group having 1 to 3 carbon atoms. 11 and R 12 , R 13 and R 14 , R 15 and R 16 , R 17 and R 18 may be bonded to each other to form a ring. 19 ~R 22 each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. d to g each independently represents an integer of 0 to 5. X 1 ~X 4 X each independently represents a single bond or a carbon atom. 1 ~X 4 is a single bond, R 11 ~R 22 Among these, the functional group connected to the single bond is excluded from general formula (15).

[0094] A specific example of the compound represented by formula (15) is bis(2,4-dicumylphenyl)pentaerythritol diphosphite, which is commercially available from Dover Chemical under the trade name "Doverphos (registered trademark) S-9228" and from ADEKA under the trade name "ADEKA STAB PEP-45" (bis(2,4-dicumylphenyl)pentaerythritol diphosphite).

[0095] The aromatic polycarbonate resin composition described above preferably satisfies at least one selected from the following: the phosphite ester compound represented by formula (12) contains tris(2,4-di-t-butylphenyl)phosphite; the phosphite ester compound represented by formula (13) contains 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine; The phosphite compound represented by the formula (14) contains 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane; and The phosphite compound represented by the formula (15) contains bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

[0096] The amount of the phosphorus-based antioxidant (D) is preferably 0.5 parts by weight or less, more preferably 0.02 to 0.2 parts by weight, based on 100 parts by weight of the aromatic polycarbonate resin (A).

[0097] The aromatic polycarbonate resin composition according to an embodiment of the present invention more preferably contains, together with the polyether derivative (B), a light diffusing agent (C), a phosphorus-based antioxidant (D), and an aromatic compound (E) represented by the following formula (1): By using the polyether derivative (B), the light diffusing agent (C), the phosphorus-based antioxidant (D), and the aromatic compound (E), it is possible to prevent deterioration of molded articles made from the resulting aromatic polycarbonate resin composition, such as deterioration due to aging, in addition to deterioration caused by the usage conditions, while maintaining the excellent optical properties required of light-diffusing molded articles.

[0098] For example, optical molded articles molded from aromatic polycarbonate resin compositions are effectively prevented from thermal degradation (clouding or coloring) due to long-term exposure to light from a light source (such as an LED light source). When light-diffusing molded articles are exposed to harsh conditions, such as under the blazing sun, and / or to prolonged light exposure, the surface temperature of the molded article may rise, gradually causing thermal degradation of the linear aromatic polycarbonate resin (A) contained in the aromatic polycarbonate resin composition. Furthermore, the polyether derivative (B) in the resin composition may be modified, impairing the transparency (brightness or light transmittance) expected of aromatic polycarbonate resin compositions used in conventional light-diffusing molded articles, and causing clouding or coloring (light to dark coloring) on ​​the surface of the molded article.

[0099] In view of this problem, the present inventors have conducted extensive research and have found that a specific aromatic compound (E) represented by the following formula (1) is particularly effective as a compound for inhibiting deterioration such as modification of the polyether derivative (B), and that by adding the specific aromatic compound (E) to the polyether derivative (B) in advance or before melt-kneading to obtain an aromatic polycarbonate resin composition, deterioration of the polyether derivative (B) in the molded article can be inhibited and the phenomenon of clouding or coloring (light to dark coloring) can be reduced or alleviated. Formula (1): [ka]

[0100] The amount of aromatic compound (E) used in the present invention is preferably 0.003 parts by weight or less per 100 parts by weight of aromatic polycarbonate resin (A). To achieve the effect of suppressing the modification of polyether derivative (B) by aromatic compound (E), the amount of aromatic compound (E) is set to 0.0001 parts by weight or more per 100 parts by weight of aromatic polycarbonate resin (A). The amount of aromatic compound (E) is more preferably 0.0005 parts by weight or more and 0.003 parts by weight or less per 100 parts by weight of aromatic polycarbonate resin (A). If the amount of aromatic compound (C) is less than 0.0001 parts by weight, the effect of suppressing cloudiness or coloration is insufficient. Conversely, if the amount of aromatic compound (C) exceeds 0.003 parts by weight, the high levels of light transmittance and color required for optically molded articles may not be achieved, which is undesirable.

[0101] In addition to the above components, the aromatic polycarbonate resin composition according to the embodiment may contain, for example, an ultraviolet absorber, which is a component that further improves the weather resistance of the resulting aromatic polycarbonate resin composition, and the ultraviolet absorber may be used as appropriate depending on the application of the molded article obtained by molding the aromatic polycarbonate resin composition.

[0102] As the ultraviolet absorber, for example, ultraviolet absorbers that are usually incorporated into polycarbonate resins, such as benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, and oxalic acid anilide-based compounds, can be used alone or in combination of two or more.

[0103] Examples of benzotriazole compounds include 2-(2-hydroxy-5-t-octylphenyl)benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole, 2-(3,5-di-tert-pentyl-2-hydroxyphenyl)-2H-benzotriazole, and 2-(2H-benzotriazole-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimid 2,2'-Methylenbis[6-(2H-benzotriazol-2-yl)4-(1,1,3,3-tetramethylbutyl)phenol], 2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole, 2-[2'-hydroxy-3,5-di(1,1-dimethylbenzyl)phenyl]-2H-benzotriazole, 2,2'-Methylenbis[6-(2H-benzotriazol-2-yl)4-(1,1,3,3-tetramethylbutyl)phenol], etc. Among these, 2-(2-hydroxy-5-t-octylphenyl)benzotriazole is particularly suitable, and commercially available products include, for example, TINUVIN 329 (TINUVIN is a registered trademark) manufactured by BASF, Seesorb 709 manufactured by Shipro Chemical Co., Ltd., and Chemisorb 79 manufactured by Chemipro Chemical Co., Ltd.

[0104] Examples of triazine compounds include 2,4-diphenyl-6-(2-hydroxyphenyl-4-hexyloxyphenyl)1,3,5-triazine, 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]phenol, and commercially available compounds include, for example, TINUVIN 1577 manufactured by BASF.

[0105] As the oxalic acid anilide compound, for example, Sanduvor VSU manufactured by Clariant Japan K.K. is commercially available.

[0106] Examples of benzophenone compounds include 2,4-dihydroxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone.

[0107] The amount of the ultraviolet absorber is 0 to 1.0 part by weight, preferably 0 to 0.5 part by weight, per 100 parts by weight of the aromatic polycarbonate resin (A). If the amount of the ultraviolet absorber exceeds 1.0 part by weight, the initial color of the resulting aromatic polycarbonate resin composition may be deteriorated. Furthermore, if the amount of the ultraviolet absorber is 0.1 part by weight or more, the effect of further improving the weather resistance of the aromatic polycarbonate resin composition is particularly significant.

[0108] The aromatic polycarbonate resin composition according to an embodiment of the present invention can contain an epoxy compound (F). When the aromatic polycarbonate resin composition simultaneously contains the polyether derivative (B), the aromatic compound (E), and the epoxy compound (F) in this manner, it is possible to maintain and improve the excellent optical properties required for a light-diffusing molded article, while preventing deterioration due to usage conditions, aging, and other degradation of the molded article made from the resulting aromatic polycarbonate resin composition without deteriorating the initial optical properties.

[0109] The epoxy compound (F) is not particularly limited as long as it has at least one epoxy group in its molecule and can produce the aromatic polycarbonate resin composition of the present invention. Examples of the epoxy compound (F) include 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, epoxidized soybean oil, ε-caprolactone-modified 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, epoxy group-containing acrylic-styrene polymers, and 2,2-bis(4-hydroxycyclohexyl)propane diglycidyl ether. The epoxy compound (F) preferably includes 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate.

[0110] The aromatic polycarbonate resin composition of the present invention preferably contains 0.001 to 0.2 parts by weight, more preferably 0.002 to 0.1 parts by weight, and particularly preferably 0.005 to 0.05 parts by weight of the epoxy compound (F) per 100 parts by weight of the linear aromatic polycarbonate resin. When the aromatic polycarbonate resin composition of the present invention contains 0.001 to 0.2 parts by weight of the epoxy compound (E) per 100 parts by weight of the linear aromatic polycarbonate resin, the excellent optical properties required for a light-diffusing molded article are maintained or improved, while the initial optical properties (integral transmittance and yellowness index) of the molded article made from the resulting aromatic polycarbonate resin composition are improved, and deterioration due to usage conditions, aging, and the like can be prevented.

[0111] Furthermore, the aromatic polycarbonate resin composition according to the embodiment may contain various additives such as a heat stabilizer, other antioxidants, colorants, release agents, softeners, antistatic agents, and impact modifiers, as well as polymers other than linear aromatic polycarbonate resins, as appropriate, within the range that does not impair the effects of the present invention.

[0112] The aromatic polycarbonate resin composition of the present invention can be produced by, for example, mixing a linear aromatic polycarbonate resin, a polyether derivative (B), and a light diffusing agent (C), and, if necessary, adding a phosphorus-based antioxidant (D), an aromatic compound (E), an epoxy compound (F), the various additives described above, and a polymer other than the linear aromatic polycarbonate resin. The production method is not particularly limited as long as the aromatic polycarbonate resin composition of the present invention can be obtained, and the type and amount of each component can be adjusted appropriately. The method for mixing the components is also not particularly limited, and examples include mixing using a known mixer such as a tumbler or ribbon blender, or melt-kneading using an extruder. These methods make it easy to obtain pellets of the aromatic polycarbonate resin composition. The aromatic compound (E) may be mixed before melt-kneading, or may be added to or mixed with the polyether derivative (B) in advance.

[0113] The shape and size of the pellets of the aromatic polycarbonate resin composition obtained as described above are not particularly limited, and may be any shape and size common to resin pellets. Examples of pellet shapes include elliptical cylinders and cylindrical shapes. The pellet size is preferably about 2 to 8 mm in length. In the case of an elliptical cylinder, the major axis of the cross-sectional ellipse is preferably about 2 to 8 mm and the minor axis is preferably about 1 to 4 mm. In the case of a cylindrical shape, the diameter of the cross-sectional circle is preferably about 1 to 6 mm. Each of the obtained pellets may be of this size, or all of the pellets forming a pellet aggregate may be of this size, or the average size of the pellet aggregate may be of this size, and there are no particular limitations.

[0114] The light-diffusing molded article according to the embodiment of the present invention can be obtained by molding the aromatic polycarbonate resin composition described above. As a large, thin light-diffusing plate (particularly a light-diffusing plate for an image display device), it is preferable to use a light-diffusing plate having a surface area of ​​500 to 50,000 cm. 2 The surface area of ​​the light diffusion plate is 1000 to 25000 cm 2The thickness is preferably 0.3 to 3 mm. As described above, the aromatic polycarbonate resin composition of the present invention can be used to produce a large, thin (lightweight) light diffusion plate having high dimensional stability.

[0115] As long as the light-diffusing molded article intended by the present invention can be obtained, the method for producing the light-diffusing molded article is not particularly limited, and examples thereof include methods of molding an aromatic polycarbonate resin composition by known injection molding methods, compression molding methods, etc.

[0116] Examples of the light-diffusing molded article according to the present invention include light diffusion plates, light diffusion films, parts for electronic and electrical devices, office automation equipment, vehicle parts, machine parts, agricultural materials, fishing materials, transport containers, packaging containers, and miscellaneous goods. Specifically, it is suitable as a light diffusion plate for an image display device (a light diffusion plate used in a backlight module of a liquid crystal display device or the like, a light diffusion plate used in a screen of a projection display device such as a projector television, etc.). For the backlight module of a liquid crystal display device or the like, various light sources (cold cathode tubes, LEDs, etc.) can be used.

[0117] Although the embodiments have been described above as examples of the present invention, the technology of the present invention is not limited to these and can be applied to embodiments in which appropriate changes, substitutions, additions, omissions, etc. are made. [Example]

[0118] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" are all by weight.

[0119] The following raw materials were used: 1. Linear aromatic polycarbonate resin: Polycarbonate resin synthesized from bisphenol A and carbonyl chloride Viscosity average molecular weight: 15,000, SD Polyca 200-80 (trade name) manufactured by Sumika Polycarbonate Co., Ltd., "SD Polyca" is a registered trademark of Sumika Polycarbonate Co., Ltd., hereinafter also referred to as (A1).

[0120] 2. Polyether derivatives (B): 2-1. Modified glycol (random copolymer) consisting of tetramethylene glycol units and propylene glycol units Weight average molecular weight: 2000, pH: 6.7 (JIS K1557-5), Polyserine DCB-2000 (trade name) manufactured by NOF Corporation, hereinafter also referred to as (B1).

[0121] 2-2. Modified glycol consisting of ethylene glycol units and propylene glycol units (random copolymer) Weight average molecular weight: 1750, Unilube 50DE-25 (trade name) manufactured by NOF Corporation, hereinafter also referred to as (B2).

[0122] 2-3. Polytetramethylene glycol Weight average molecular weight: 1000, PTG-1000SN (trade name) manufactured by Hodogaya Chemical Co., Ltd., hereinafter also referred to as (B3)

[0123] 3. Light diffuser (C): 3-1. Polymethylsilsesquioxane-based diffusing agent SL-200M (product name) manufactured by Samsung, hereinafter referred to as (C1). 3-2. Acrylic diffusing agent GM-0449S (product name) manufactured by Aica Kogyo Co., Ltd., hereinafter also referred to as (C2). 3-3. Styrene-methyl methacrylate copolymer crosslinked particles SMX-12R (product name) manufactured by Sekisui Plastics Co., Ltd., hereinafter also referred to as (C3). 3-4. Inorganic diffusing agent (titanium oxide) TIPAQUE (registered trademark) PC-3 (product name) manufactured by Ishihara Sangyo Kaisha, Ltd. (hereinafter also referred to as (C4))

[0124] 4. Phosphorus-based antioxidants (D): 4-1. Tris(2,4-di-t-butylphenyl)phosphite, represented by the following formula: [ka] Irgafos 168 (trade name) manufactured by BASF, hereinafter also referred to as (D1).

[0125] 4-2. 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine represented by the following formula: [ka] Sumilizer GP (trade name) manufactured by Sumitomo Chemical Co., Ltd., hereinafter also referred to as (D2).

[0126] 4-3. Bis(2,4-dicumylphenyl)pentaerythritol diphosphite (IUPAC name: 3,9-bis[2,4-bis(α,α-dimethylbenzyl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane) represented by the following formula: [ka] Doverphos S-9228 (trade name) manufactured by Dover Chemical Co., hereinafter also referred to as (D3).

[0127] 4-4. Bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite (IUPAC name: 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane) represented by the following formula: [ka] ADEKA's ADK STAB PEP-36 (product name), hereafter also referred to as (D4). 5.Aromatic compounds (E): 3,5-di-t-butyl-4-hydroxytoluene Manufactured by Wako Pure Chemical Industries, Ltd., hereinafter also referred to as (E1).

[0128] 6. Epoxy compounds (F) 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate Celloxide 2021P (trade name) manufactured by Daicel Chemical Industries, Ltd., hereinafter also referred to as (F1).

[0129] (Examples 1 to 14 and Comparative Examples 1 and 2) The raw materials were all charged into a tumbler in the proportions shown in Table 1 and dry-mixed for 10 minutes, and then melt-kneaded at a melting temperature of 230°C using a twin-screw extruder (TEX30α, manufactured by The Japan Steel Works, Ltd.) to obtain pellets of the aromatic polycarbonate resin composition of each of Examples 1 to 11 and Comparative Examples 1 and 2. The pellets obtained in the Examples and Comparative Examples were all approximately elliptical cylindrical, and an aggregate consisting of 100 pellets had an average length of about 5.1 mm to about 5.4 mm, an average major axis of the elliptical cross section of about 4.1 mm to about 4.3 mm, and an average minor axis of about 2.2 mm to about 2.3 mm.

[0130] Using the obtained pellets, test pieces for evaluation were prepared according to the following method and subjected to evaluation. The results are shown in Table 1.

[0131] (Method of preparing test specimens) The obtained pellets were dried at 120°C for 4 hours or more, and then an injection molding machine (FANUC Corporation, ROBOSHOT S2000i100A) was used to prepare three-tiered plate-shaped test pieces (3 mm thick part: length 35 mm / 2 mm thick part: length 30 mm / 1 mm thick part: length 25 mm) with a molding temperature of 290°C and a mold temperature of 80°C.

[0132] (Test piece evaluation method) 1.Total light transmittance (%): Using a 1 mm section of the obtained three-stage plate-shaped test piece, the total light transmittance was measured in accordance with JIS K7361. The higher the value, the better the light transmittance of the molded product. A total light transmittance value of 40% or more for a 1 mm thick molded product was rated as good (○), and anything else was rated as x.

[0133] 2. Light diffusion (degrees): Using a 1 mm section of the three-step plate-shaped test piece used in 1 above, the light diffusion (D50) was determined using an automatic variable angle photometer (Goniophotometer GP-1R, manufactured by Murakami Color Research Laboratory). The detailed measurement method is as follows. The higher this value, the better the light diffusion of the molded product. A straight beam of light from the light source of the automatic variable angle photometer was directed at the test piece from the normal direction, the intensity of the transmitted light was measured using a movable light receiver, and the transmittance was plotted against the angle from the normal direction to determine the angle (D50) at which the transmittance was 50% of the straight light transmittance. The unit of measurement is degrees, and a light diffusion (D50) of 30 degrees or more was considered good.

[0134] 3. Prevention of light source see-through (visual judgment): A 3cm x 5cm rectangular hole was drilled in the center of a Philips 20W straight tube LED lamp, and a 3cm x 5cm x 1mm injection molded plate was placed in that location at a height of approximately 1.5cm from the LED light source. The light source visibility prevention was judged visually from a height of approximately 20cm above the injection molded plate placed on the LED lamp. If the plate had sufficient light diffusion and the outline of the LED light source had disappeared, it was judged as extremely good ◎. If the outline of the LED light source was somewhat visible, it was judged as good ○, and if the light diffusion was poor and the outline of the LED light source was clearly visible, it was judged as poor ×.

[0135] 4.Yellowness: Using a 1 mm section of the obtained three-tiered plate-shaped test piece, the yellowness index (hereinafter referred to as YI) of each test piece before and after the heating test was determined using a spectrophotometer (Hitachi, Ltd., UH4150) with a standard illuminant D65 and a 10-degree field of view. The heating test was performed by placing the test piece in an inert oven IPHH-201M manufactured by Espec Corporation and holding it at 90°C for 500 hours. A YI of 4.0 or less was rated as good (◎), a YI of more than 4.0 to 5.0 or less was rated as usable (○), and a YI of more than 5.0 was rated as poor (×).

[0136] Tables 1 to 3 show the raw materials and blending ratios of each example and comparative example, as well as the evaluation results. [Table 1] [Table 2] [Table 3]

[0137] The aromatic polycarbonate resin compositions of Examples 1 to 14 contain a linear aromatic polycarbonate resin, a polyether derivative (B), and a light diffusing agent (C), and optionally contain a phosphorus-based antioxidant (D), an aromatic compound (E), an epoxy compound (F), etc., each in a specific ratio. Therefore, test pieces molded from the aromatic polycarbonate resin compositions have the required high total light transmittance, light diffusibility, and light source visibility prevention properties, low yellowness, and show almost no deterioration after a heating test.

[0138] Furthermore, molded articles made from such aromatic polycarbonate resin compositions have a low yellow index and excellent hue, and furthermore, they hardly deteriorate after a heating test.

[0139] In contrast, the aromatic polycarbonate resin composition of Comparative Example 1 had a low light diffusion rate and poor light source visibility prevention because of the small amount of light diffusing agent blended in. Furthermore, the aromatic polycarbonate resin composition of Comparative Example 2 had a low total light transmittance because of the large amount of light diffusing agent blended in.

[0140] The embodiments have been described above as examples of the technology of the present invention, and detailed descriptions have been provided for that purpose.

[0141] Therefore, the components described in the detailed description may include not only components essential for solving the problem but also components that are not essential for solving the problem in order to exemplify the above technology. Therefore, the fact that these non-essential components are described in the detailed description should not be interpreted as immediately being essential.

[0142] Furthermore, since the above-described embodiments are intended to illustrate the technology of the present invention, various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0143] The aromatic polycarbonate resin composition of the present invention does not impair the inherent properties of polycarbonate resins, such as heat resistance and mechanical strength, and is excellent in thermal stability and weather resistance. Moreover, even when a molded article containing the aromatic polycarbonate resin composition of the present invention is heated, it maintains excellent appearance and optical properties. Therefore, even when used in applications where a heated state is continued due to long-term irradiation of the surface of a diffuser plate from a thin diffused light source with a thickness of about 0.3 mm, for example, the hue of the resulting diffuser plate does not change and the appearance and optical properties do not deteriorate, making it extremely valuable for industrial use.

Claims

1. An aromatic polycarbonate resin composition comprising a linear aromatic polycarbonate resin (A), a polyether derivative (B), a light diffusing agent (C), a phosphorus-based antioxidant (D), and an aromatic compound (E) represented by the following formula (1): The aromatic polycarbonate resin composition contains, relative to 100 parts by weight of the linear aromatic polycarbonate resin (A), 0.1 to 2.0 parts by weight of a polyether derivative (B), 0.1 to 6.0 parts by weight of a light diffusing agent (C), up to 0.5 part by weight of a phosphorus-based antioxidant (D), and up to 0.003 part by weight of an aromatic compound (E). Formula (1): 【Chemistry 1】

2. 2. The aromatic polycarbonate resin composition according to claim 1, wherein the light diffusing agent (C) has a mass average particle size of 0.5 to 3 μm.

3. 2. The aromatic polycarbonate resin composition according to claim 1, wherein the polyether derivative (B) is represented by the following formula (2) and comprises a polyether derivative having a weight average molecular weight of 500 to 8,000: Formula (2): RO-(X-O)m(Y-O)n-R' (In the formula, R and R' each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms; X represents a linear or branched alkylene group having 2 to 4 carbon atoms; Y represents a linear or branched alkylene group having 2 to 5 carbon atoms; X and Y may be the same or different; m and n each independently represent a number from 3 to 60; and m+n represents a total of 6 to 120.)

4. 2. The aromatic polycarbonate resin composition according to claim 1, wherein the light diffusing agent (C) is a silicone-based light diffusing agent, an acrylic-based light diffusing agent, inorganic fine particles, or a combination thereof.

5. 2. The aromatic polycarbonate resin composition according to claim 1, further comprising at least one selected from the group consisting of a heat stabilizer, a colorant, a release agent, a softener, an antistatic agent, and an impact modifier.

6. A light-diffusing molded article comprising the aromatic polycarbonate resin composition according to any one of claims 1 to 5.

7. The light-diffusing molded article according to claim 6, which is a light-diffusing plate or film for an image display device.

Images