JP2006298980A - Polycarbonate resin composition and molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition excellent in heat resistance during molding, ultraviolet resistance, and lightfastness and heat stability when irradiated with light for a long period of time, and thus having a well-balanced performance overall, and to provide a molded article obtained by molding the same. <P>SOLUTION: The polycarbonate resin composition comprises 100 pts.wt. of an aromatic polycarbonate resin (A), 3-50 pts.wt. of titanium oxide (B), and 0.001-0.15 pt.wt. of a benzoxazole compound (C) having a thiophene structure. The molded article is obtained by molding the resin composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polycarbonate-based resin composition and a molded product obtained by molding the polycarbonate-based resin composition, and particularly relates to a resin composition and a molded product suitable for uses such as a light reflector and its peripheral parts.

  Aromatic polycarbonate resins have excellent mechanical properties, thermal properties, and electrical properties, and are widely used industrially including the automotive field, OA equipment field, and electrical / electronic field. For example, polycarbonate resin compositions in which white pigments such as surface-treated titanium oxide are added to aromatic polycarbonate resins include backlights for liquid crystal display devices such as computers and televisions, illuminated push switches, and reflectors for photoelectric switches. It is used as a material.

Recently, the trend of thinning and increasing the size of reflectors and their peripheral components has become stronger due to the increasing thickness and size of display devices such as televisions and personal computers. Along with this tendency, light reflecting resin materials such as reflectors are molded under conditions that are severer at higher temperatures than conventional ones, so that excellent heat resistance during molding is required.
On the other hand, there is a demand for a clearer image display device. In particular, for a liquid crystal display device for a television monitor, there is an increasing demand for high performance such as higher backlight brightness and improved white reproducibility. Along with this demand, the light source of the backlight is changed from the conventional cold cathode fluorescent lamp to the LED, and the use conditions are remarkably severe due to the change of the light source. For example, when a cold cathode tube is used as a light source, the temperature in the vicinity of the reflector is about 60 ° C., whereas when the LED is used as a light source, the temperature rises to about 80 ° C. Therefore, even when irradiated with light for a long period of time, it is also necessary to exhibit good light resistance and thermal stability.

  Conventionally, in order to make a molded article look brighter, various resin compositions such as coumarin derivatives, naphthotriazolyl stilbene derivatives, benzoxazole derivatives, oxazole derivatives, benzimidazole derivatives and diaminostilbene-disulfonate derivatives have been included in the resin composition. It is known to add a fluorescent brightening agent. However, the effect varies greatly depending on the structure of the compound, not only the heat resistance during molding (light reflectance, hue, impact resistance, appearance, etc.), but also UV resistance and light resistance when irradiated for a long period of time. From the viewpoint of excellent performance and thermal stability and a comprehensively balanced performance, a suitable optical brightener has not been studied.

  In response to the strict requirements as described above, Patent Documents 1 and 2 disclose that a light reflector formed of a polycarbonate resin composition containing a polycarbonate resin, titanium oxide, and a stilbene bisbenzoxazole derivative has impact resistance and light resistance. It is disclosed that it has excellent reflection characteristics and light resistance. However, Patent Documents 1 and 2 are still unsatisfactory from the viewpoint of exhibiting a comprehensively balanced performance.

JP 10-36656 A JP 2002-201349 A

  The object of the present invention is excellent in heat resistance at the time of molding (light reflectance, hue, impact resistance, appearance, etc.), UV resistance, and light resistance and thermal stability when irradiated with light for a long time. Another object of the present invention is to provide a resin composition having excellent performance and a comprehensively balanced performance, and a molded product formed by molding the resin composition.

  As a result of intensive studies to achieve the above object, the present inventor has obtained a benzoxazole-based thiophene structure in a polycarbonate-based resin composition containing an aromatic polycarbonate resin (A) and titanium oxide (B). By compounding a specific amount of the compound (C), it is excellent in heat resistance during molding, excellent in ultraviolet resistance, and excellent in light resistance and thermal stability when irradiated with light for a long period of time. The present inventors have found that a resin composition having a well-balanced performance can be obtained and completed the present invention.

  That is, the gist of the present invention is that 3 to 50 parts by weight of titanium oxide (B) and benzoxazole-based compound (C) having a thiophene structure are 0.001 to 100 parts by weight of aromatic polycarbonate (A). The present invention resides in a polycarbonate-based resin composition characterized by containing .about.0.15 parts by weight, and a molded product characterized by molding the resin composition.

According to the present invention, it has excellent heat resistance during molding such as light reflectance, hue, impact resistance, appearance, etc., and also has excellent UV resistance, and even when irradiated with light for a long period of time and exposed to light. Since changes in performance such as reflectance, hue, and mechanical strength are suppressed, it is possible to obtain a resin composition and a molded product that are excellent in light resistance and thermal stability and have a comprehensively balanced performance.
Therefore, the resin composition of the present invention is suitable for a molded article for light reflection and its peripheral members. For example, it is useful as a peripheral member such as a light beam reflector for a backlight of a liquid crystal display device and a frame, an illumination device such as an advertisement light, an automobile device such as an automotive meter panel, and particularly useful as a light reflector. is there.

In particular, since the resin composition of the present invention is excellent in light resistance and thermal stability, it is used as a reflector for a display device using an LED used as a light source at a high temperature of about 80 ° C. and a molded product as a peripheral part thereof. Is preferred.
By adding a non-halogen flame retardant to the resin composition of the present invention, in addition to the above-described performance, further flame retardancy is imparted, and a resin composition and molded product free from environmental pollution are obtained. be able to.

Hereinafter, the present invention will be described in detail.
Aromatic polycarbonate (A)
The aromatic polycarbonate resin (A) used in the present invention may be branched, which is obtained by reacting an aromatic hydroxy compound or a small amount of this with a phosgene or a carbonic acid diester. It is a thermoplastic aromatic polycarbonate polymer or copolymer. As a method for producing the aromatic polycarbonate resin (A), for example, a known method such as a phosgene method (interfacial polymerization method) or a melting method (transesterification method) can be employed. Moreover, you may use resin manufactured by the melting method and adjusting the amount of terminal OH groups.

  As the raw material aromatic dihydroxy compound, 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone, resorcinol, 4 , 4-dihydroxydiphenyl, etc., among which bisphenol A is preferred. These aromatic dihydroxy compounds can be used alone or in admixture of two or more. In order to increase the flame retardancy of the resin composition of the present invention, a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the aromatic dihydroxy compound can be used.

  Moreover, in order to obtain the branched aromatic polycarbonate resin (A), a part of the above-mentioned aromatic dihydroxy compound is replaced with the following compounds: phloroglucin, 4,6-dimethyl-2,4,6-tris (4- Hydroxyphenyl) heptene-2,4,6-dimethyl-2,4,6-tris (4-hydroxyphenyl) heptane, 2,6-dimethyl-2,4,6-tris (4-hydroxyphenylheptene)- Polyhydroxy compounds such as 3,1,3,5-tris (4-hydroxyphenyl) benzene and 1,1,1-tris (4-hydroxyphenyl) ethane, and 3,3-bis (4-hydroxyaryl) oxy Replace with compounds such as indole (= isatin bisphenol), 5-chloruisatin, 5,7-dichloroisatin, 5-bromoisatin, etc. . The amount of the compound to be substituted is 0.01 to 10 mol%, preferably 0.1 to 2 mol%, based on the aromatic dihydroxy compound.

Among the above-mentioned, as the aromatic polycarbonate resin (A), a polycarbonate resin derived from bisphenol A or a polycarbonate copolymer derived from bisphenol A and another aromatic dihydroxy compound is preferable. Moreover, in order to improve the flame retardance of a resin composition, the copolymer of the polymer or oligomer which has bisphenol A and a siloxane structure can also be used. Furthermore, the aromatic polycarbonate (A) may be used by mixing two or more kinds of resins.
The molecular weight of the aromatic polycarbonate resin (A) is preferably 16,000 to 30,000, more preferably 17, in terms of viscosity average molecular weight converted from the solution viscosity measured at 25 ° C. using methylene chloride as a solvent. 000 to 23,000.

Titanium oxide (B)
The titanium oxide (B) used in the present invention is not particularly limited, but among these, titanium (IV) oxide, that is, titanium dioxide (TiO ₂ ) is preferable. The crystal form of titanium dioxide may be any of rutile type (tetragonal system) and anatase type (orthorhombic system), but rutile type titanium dioxide is particularly preferable. Rutile-type titanium dioxide is superior to anatase-type titanium dioxide in terms of whiteness, light reflectance, and ultraviolet resistance. Titanium dioxide may be produced from ilmenite (titanite) or rutile ore by any of the chlorine method and sulfuric acid method, and among these, titanium dioxide produced by the chlorine method is preferred. By employing the chlorine method, it is possible to produce the above-described rutile crystal form of titanium dioxide.

  The average particle diameter of titanium oxide (B) used in the present invention is preferably 0.05 to 0.5 μm. When the particle diameter of titanium oxide is less than 0.05 μm, the light shielding properties and light reflectance tend to decrease, and when it exceeds 0.5 μm, the light shielding properties and light reflectance are decreased, and on the surface of the molded product. There is a tendency for rough skin and impact resistance to decrease. The particle diameter of titanium oxide (B) is more preferably 0.1 to 0.4 μm, and most preferably 0.15 to 0.35 μm.

  On the other hand, it is preferable that the titanium oxide (B) used by this invention is what surface-treated with the organic compound. In particular, when titanium oxide that has not been surface-treated with an inorganic treating agent to be described later is used, it is necessary to perform surface treatment with an organic compound. Examples of the organic compound that is the surface treatment agent include an alkoxy group, an epoxy group, an amino group, an organic silane compound having an Si—H bond, or an organic silicone compound, and among them, an organic silicone having an Si—H bond is preferable. A compound. The amount of the organic compound used as the surface treatment agent is preferably 1 to 5% by weight, more preferably 1.5 to 3% by weight, based on titanium oxide (B).

  In general, titanium oxide is often surface-treated with an inorganic hydrous oxide (inorganic treating agent) such as silica or alumina from the viewpoint of weather resistance and handling properties, but as titanium oxide (B) used in the present invention. In view of thermal stability, it is preferable to reduce the amount of the inorganic treatment agent or use titanium oxide that has not been surface-treated with the inorganic treatment agent. The amount of the inorganic treatment agent used is preferably 2% by weight or less with respect to titanium oxide, and more preferably 0% by weight, that is, the treatment with the inorganic treatment agent is not performed. When the surface treatment is performed with an inorganic treatment agent, silica, alumina, zirconia, or a mixture thereof is used as the inorganic treatment agent. However, since silica has high water absorption and is easily affected by moisture, Among these, alumina and zirconia are preferable as the treating agent. When silica is used in combination, the amount of silica is preferably small.

  The amount of titanium oxide (B) blended in the resin composition of the present invention (including the amount of the surface treatment agent) is 3 to 50 parts by weight with respect to 100 parts by weight of the aromatic polycarbonate resin (A). When the blending amount of titanium oxide (B) is less than 3 parts by weight, the light reflectivity becomes insufficient, and when it exceeds 50 parts by weight, the impact resistance becomes insufficient. The amount of titanium oxide (B) is preferably 5-30 parts by weight, more preferably 8-25 parts by weight, per 100 parts by weight of the aromatic polycarbonate resin (A).

Benzoxazole compounds (C)
The benzoxazole-based compound (C) used in the present invention is a benzoxazole-based compound having a thiophene structure, has a fluorescent whitening effect, and has an effect of eliminating the yellowness of the molded product and increasing the brightness. In this respect, it is similar to the bluing agent, but the bluing agent removes yellow light, whereas the benzoxazole compound (C), which has a fluorescent whitening action, absorbs ultraviolet rays and absorbs its energy. It is different in that it is emitted in the visible part of blue-violet rays.

In the present invention, the benzoxazole-based compound is a compound including a structure composed of benzoxazole and a benzoxazole derivative, and the benzoxazole derivative is a compound having various substituents on benzoxazole, hydrogenated products thereof, and the like. Point to.
The benzoxazole-based compound (C) of the present invention has a thiophene structure, and among them, a compound represented by the following general formula (1) is preferable.

（一般式（１）中、Ｒ_１及びＲ_２は、各々独立に炭素数１〜１０のアルキル基を表し、ｎ及びｍは、各々独立に０〜３の整数を表す。）

(In General Formula (1), R ₁ and R ₂ each independently represent an alkyl group having 1 to 10 carbon atoms, and n and m each independently represent an integer of 0 to 3)

In general formula (1), R ₁ and R ₂ each independently represent a linear or branched alkyl group having 1 to 10 carbon atoms, among which an alkyl group having 2 to 8 carbon atoms is preferable, and Is preferably a branched alkyl group having 3 to 6 carbon atoms. n and m each independently represents an integer of 0 to 3, but is preferably an integer of 1 or 2, and more preferably 1. Further, the substitution position of R ₁ and R ₂ is not particularly limited, but it is preferably substituted at the 5-position.

  Examples of the compound represented by the general formula (1) include 2,5-bis [5′-t-butylbenzoxazolyl (2)] thiophene, 2,5-bis [5′-isobutylbenzoxazolyl ( 2)] thiophene, 2,5-bis [5′-i-propylbenzoxazolyl (2)] thiophene, 2,5-bis [5′-i-pentylbenzoxazolyl (2)] thiophene, 2,5 -Bis [5′-neopentylbenzoxazolyl (2)] thiophene, among others, 2,5-bis [5′-t-butylbenzoxazolyl (2)] thiophene represented by the following structural formula Is preferred.

  In the present invention, the blending amount of the benzoxazole-based compound (C) is 0.001 to 0.15 parts by weight, preferably 0.005 to 0.10 parts by weight with respect to 100 parts by weight of the aromatic polycarbonate resin. Parts, more preferably 0.08 to 0.05 parts by weight. If the blending amount is less than 0.001 part by weight, the effect as a fluorescent brightening agent is small. If the blending amount exceeds 0.15 part by weight, the thermal stability at the time of molding is lowered, which is disadvantageous in terms of cost.

  In the resin composition of the present invention, the blending amount (C / B) of the benzoxazole-based compound (C) with respect to the above-described titanium oxide (B) is usually 1/100 to 1/10000 in weight ratio. The ratio is preferably 1/500 to 1/5000, and more preferably 1/1000 to 1/3000.

In the present invention, it is preferable to further blend a phosphite ester compound (D-1) and / or a hindered phenol compound (D-2).
Phosphite ester compound (D-1)
As the phosphite compound (D-1), from the viewpoint of thermal stability and weather resistance, polyphosphite, more preferably bisphosphite is preferable, and bisphosphite having a cyclic structure, in particular, A compound represented by the general formula (2) is preferable.

（一般式（２）中、Ｒ_３及びＲ_４は、各々独立にアルキル基又はアリール基であり、置換基を有していてもよい。）

(In General Formula (2), R ₃ and R ₄ are each independently an alkyl group or an aryl group, and may have a substituent.)

R ₃ and R ₄ in the general formula (2) are each independently an alkyl group or an aryl group, which may have a substituent, and among them, an optionally substituted phenyl The group is preferable, and further, a phenyl group which may be substituted and which is represented by the following general formula (3) or (4) is preferable.

（一般式（３）中、Ｒ_１及びＲ_２は、各々独立に、炭素数１〜１０のアルキル基、又は、炭素数７〜２０のアリールアルキル基である。）
一般式（３）中の、Ｒ_１及びＲ_２としては、中でも、各々独立に、炭素数２〜５のアルキル基、又は、炭素数７〜１２のフェニルアルキル基が好ましい。

(In General Formula (3), R ₁ and R ₂ are each independently an alkyl group having 1 to 10 carbon atoms or an arylalkyl group having 7 to 20 carbon atoms.)
As R ₁ and R ₂ in the general formula (3), an alkyl group having 2 to 5 carbon atoms or a phenylalkyl group having 7 to 12 carbon atoms is preferable.

（一般式（４）中、Ｒ_１及びＲ_２は、各々独立に、炭素数１〜１０のアルキル基である。）
一般式（４）中の、Ｒ_１及びＲ_２としては、中でも、各々独立に、炭素数１〜６のアルキル基、更には炭素数３〜５の分岐状アルキル基が好ましい。

(In General Formula (4), R ₁ and R ₂ are each independently an alkyl group having 1 to 10 carbon atoms.)
As R < ₁ > and R < ₂ > in General formula (4), a C1-C6 alkyl group and also a C3-C5 branched alkyl group are respectively preferable especially.

Among the phosphite compounds (D-1) represented by the general formula (2), examples of the compound in which R ₃ and R ₄ are groups represented by the general formula (3) include: Bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite (Adeka Stub PEP-24G manufactured by Asahi Denka Kogyo Co., Ltd.), bis (2,4-di-i-propylphenyl) pentaerythritol diphosphite And bis (2,4-di-neopentylphenyl) pentaerythritol diphosphite. Moreover, bis (2,4-dicumylphenyl) pentaerythritol diphosphite (Doverfos S-9228 manufactured by Dover Chemical Co., Ltd.) is exemplified as R ₃ and R ₄ represented by the following structural formula. .
Among these, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite and bis (2,4-dicumylphenyl) pentaerythritol diphosphite are preferable.

Examples of the compound in which R ₃ and R ₄ are a group represented by the above general formula (4) include, for example, cyclic neopentanetetraylbis (2,6-di-t-butyl-4-methylphenyl). ) Diphosphite (Adeka Stub PEP-36 manufactured by Asahi Denka Kogyo Co., Ltd.), cyclic neopentanetetraylbis (2,6-i-propyl-4-methylphenyl) diphosphite, cyclic neopentanetetraylbis (2, 6-di-neopentyl-4-methylphenyl) diphosphite and the like are mentioned, among which cyclic neopentanetetraylbis (2,6-di-t-butyl-4-methylphenyl) diphosphite is preferable.

  In the present invention, the phosphite compound (D-1) is 0.001 to 1 part by weight, preferably 0.005 to 0.8 part by weight, based on 100 parts by weight of the aromatic polycarbonate resin (A). More preferably 0.01 to 0.5 part by weight is blended. In the resin composition of the present invention, the blending amount (D-1 / B) of the phosphite compound (D-1) with respect to the above-described titanium oxide (B) is usually 1/30 by weight ratio. Is 1/800, preferably 1/50 to 1/500, and more preferably 1/100 to 1/350. Further, the blending amount (D-1 / C) of the phosphite compound (D-1) with respect to the benzoxazole compound (C) is usually 1/1 to 1/50 by weight, preferably 1/3 to 1/30, more preferably 1/5 to 1/20.

  Moreover, in this invention, it is preferable to mix | blend a hindered phenol type compound (D-2) further. Among them, the hindered phenol compound (D-2) is preferably a compound represented by the following general formula (5) from the viewpoint of thermal stability and weather resistance.

（一般式（５）中、Ｒ_５及びＲ_６は各々独立に、炭素数１〜１０のアルキル基を表し、Ｒ_７及びＲ_８は各々独立に、炭素数１〜５のアルキレン基を表す。）
一般式（５）中、Ｒ_５及びＲ_６は、中でも、各々独立に、炭素数１〜６のアルキル基、更には、炭素数３〜５の分岐状アルキル基が好ましく、Ｒ_７及びＲ_８は、中でも、各々独立に、炭素数１〜３のアルキレン基が好ましい。

(In General Formula (5), R ₅ and R ₆ each independently represent an alkyl group having 1 to 10 carbon atoms, and R ₇ and R ₈ each independently represent an alkylene group having 1 to 5 carbon atoms. )
In general formula (5), R ₅ and R ₆ are each independently preferably an alkyl group having 1 to 6 carbon atoms, more preferably a branched alkyl group having 3 to 5 carbon atoms, and R ₇ and R _8. Among these, an alkylene group having 1 to 3 carbon atoms is preferable independently.

As a compound represented by the general formula (5), pentaerythritol tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) (Irganox 1010 manufactured by Ciba Specialty Chemicals Co., Ltd.) ), Pentaerythritol tetrakis (3- (3,5-di-i-propyl-4-hydroxyphenyl) propionate), pentaerythritol tetrakis (3- (3,5-di-neopentyl-4-hydroxyphenyl) propionate), etc. Among them, pentaerythritol tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) is preferable.
In the present invention, the hindered phenol compound (D-2) is 0.001 to 1 part by weight, preferably 0.01 to 0.8 part by weight, based on 100 parts by weight of the aromatic polycarbonate resin (A). Preferably, 0.05 to 0.5 part by weight is blended.

  In the present invention, the above-described phosphite compound (D-1) and hindered phenol compound (D-2) are effective as antioxidants even if each compounded alone in the resin composition. Preferably, by using the phosphite compound (D-1) and the hindered phenol compound (D-2) in combination, the hue change during molding such as extrusion molding or injection molding is suppressed, and The hue change when exposed to a high temperature for a long time, such as when using a molded product, can be remarkably suppressed.

  When the phosphite compound (D-1) and the hindered phenol compound (D-2) are used in combination, the total blending amount thereof is 100 parts by weight of the aromatic polycarbonate resin (A). 0.002 to 2 parts by weight, preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.5 part by weight. The blending ratio of the phosphite compound (D-1) and the hindered phenol compound (D-2) is (D-1) :( D-2), usually 5: 1 to 1:10. And preferably 3: 1 to 1: 8, more preferably 1: 1 to 1: 3.

Flame retardant (E)
In this invention, when it is necessary to provide a flame retardance to a resin composition, it is preferable to mix | blend a non-halogen flame retardant (E).
Non-halogen flame retardant (E) includes non-halogen phosphate ester (E-1), silicone compound (E-2), and alkali metal salt or alkaline earth of perfluoroalkanesulfonic acid or perfluoroalkylene disulfonic acid. At least one selected from metal salts (E-3) is preferred, and can be appropriately selected from these, and these may be used in combination.

  The non-halogen phosphate ester (E-1) used in the present invention is a flame retardant containing phosphorus in the molecule and not containing a halogen atom. Preferably, the compound represented by the following general formula (6) is used. Can be mentioned.

(In General Formula (6), R ₉ , R ₁₀ , R _11, and R ₁₂ are each independently an alkyl group having 1 to 6 carbon atoms, or an optionally substituted alkyl group having 6 to 20 carbon atoms. And p, q, r and s are each independently 0 or 1, l is an integer of 1 to 5, and X represents an arylene group.)
Among the general formula (6), R ₉ , R ₁₀ , R ₁₁ and R ₁₂ are each independently preferably an aryl group having 6 to 18 carbon atoms which may be substituted with an alkyl group, and p, q, r And s are each independently preferably 1, 1 is preferably an integer of 1 to 3, and X is preferably a resorcinol residue or a bisphenol A residue.

  The non-halogen phosphate ester (E-1) represented by the general formula (6) is a condensed phosphate ester in which 1 is 1 to 5, and when used as a mixture of condensed phosphate esters in which l is different, The value is the average value of the mixture. Examples of X that is an arylene group include groups derived from dihydroxy compounds such as resorcinol, hydroquinone, and bisphenol A. Among them, a group derived from resorcinol and bisphenol A is preferable.

  Specific examples of the non-halogen phosphate ester (E-1) represented by the general formula (6) include, when X is derived from bisphenol A, phenyl bisphenol polyphosphate, cresyl bisphenol poly Phosphate, phenyl, cresyl, bisphenol, polyphosphate, xylyl, bisphenol, polyphosphate, phenyl-pt-butylphenyl, bisphenol, polyphosphate, phenyl, isopropylphenyl, bisphenol, polyphosphate, cresyl, xylyl, bisphenol, polyphosphate , Phenyl isopropylphenyl diisopropylphenyl bisphenol polyphosphate. Among these, phenyl bisphenol polyphosphate is preferable.

  The blending amount of the non-halogen phosphate ester (E-1) is preferably 2 to 20 parts by weight with respect to 100 parts by weight of the aromatic polycarbonate resin (A). When the addition amount of the non-halogen phosphate ester (E-1) is less than 2 parts by weight, the effect of improving the flame retardancy tends to be insufficient, and when it exceeds 20 parts by weight, the mechanical properties tend to decrease. . The blending amount of the non-halogen phosphate ester (E-1) is more preferably 3 to 18 parts by weight, still more preferably 5 to 15 parts by weight with respect to 100 parts by weight of the aromatic polycarbonate resin (A).

  In the present invention, as the silicone compound (E-2) that can be used as the non-halogen flame retardant (E), when blended with the aromatic polycarbonate resin (A), the flame retardancy can be improved. Various silicones or silicone-containing compounds may be mentioned. As the silicone compound (E-2), specifically, (1) a powdery silicone compound having a polyorganosiloxane polymer supported on the surface of silica powder, and (2) the main chain has a branched structure. A branched silicone compound having an aromatic group bonded to silicon, and (3) a silicone compound comprising a mixture of an aromatic group-containing cyclic polyorganosiloxane and a linear polyorganosiloxane.

(1) Examples of the silica powder used in the powdery silicone compound having a polyorganosiloxane polymer supported on the surface of the silica powder include fumed silica, finely pulverized silica obtained from a precipitation method or mining form. In the case of fumed silica and precipitated silica, the silica powder preferably has a surface area in the range of 50 to 400 m ² / g. When the surface area is in this range, the polyorganosiloxane polymer is easily supported (absorbed, adsorbed or retained) on the surface. When using the silica powder in the mined form, it is preferable to use a silica powder in which at least an equal weight of fumed silica or precipitated silica is combined, and the surface area of the mixture is in the range of 50 to 400 m ² / g.

  The silica powder can be surface-treated with a surface treatment agent other than the polyorganosiloxane polymer before supporting the polyorganosiloxane polymer. Examples of the surface treating agent include low molecular weight polyorganosiloxanes having a hydroxy group or an alkoxy group as a terminal group, hexaorganodisiloxane, and hexaorganodisilazane. Among these, an oligomer having an average degree of polymerization of 2 to 100 is preferable, and polydimethylsiloxane having a hydroxyl group as a terminal group and a liquid or viscous oil at room temperature is preferable.

The surface of the silica powder or the surface-treated silica powder is further treated with a polyorganosiloxane polymer. The polyorganosiloxane polymer may have a straight chain or a branched chain, and among them, a linear polydiorganosiloxane polymer is more preferable. The organic group (organo group) of the polyorganosiloxane polymer is an alkyl group having 1 to 20 carbon atoms which may be substituted with a halogen atom or the like, an alkenyl group such as vinyl or 5-hexenyl, or a cyclohexane such as a cyclohexyl group. It is selected from alkyl groups, phenyl groups, tolyl groups, aryl groups such as benzyl groups, and aralkyl groups. Preferred are alkyl groups having 1 to 4 carbon atoms, phenyl groups, and halogenated alkyl groups such as 3,3,3-trifluoropropyl, more preferred are alkyl groups having 1 to 3 carbon atoms, especially A methyl group is preferred.
The viscosity of the polyorganosiloxane polymer is preferably 10,000 to 200,000 centistokes, more preferably 30,000 to 100,000 centistokes.

  The polyorganosiloxane polymer may have a functional group in the molecular chain. Although it does not specifically limit as a functional group, A methacryl group or an epoxy group is preferable. When it has a methacryl group or an epoxy group, a crosslinking reaction with the aromatic polycarbonate resin (A) can be caused at the time of combustion, so that the flame retardancy of the resin composition can be further improved. The amount of the functional group in the polyorganosiloxane polymer molecular chain is usually 0.01 to 1 mol%, preferably 0.03 to 0.5 mol%, more preferably 0.05 to 0.00 mol%. 3 mol%.

  When the polyorganosiloxane polymer is supported on silica powder, it is preferable to use an adhesion promoter. By using an adhesion promoter, the interface between the silica powder and the polyorganosiloxane polymer can be adhered more firmly. Examples of the adhesion promoter include alkoxysilane adhesion promoters. The alkoxysilane-based adhesion promoter has a C 1-4 alkoxy group, epoxy group, acryloxy group, methacryloxy group, vinyl group, phenyl group, and N-β- (N-vinylbenzylamino) in the molecular chain. ) Compounds having at least one group selected from ethyl-γ-aminoalkyl hydrochloride are preferred.

As the alkoxysilane-based adhesion promoter, a compound represented by the general formula Y—Si (OCH ₃ ) ₃ is particularly preferable. In the above general formula, Y represents an epoxyalkyl group, an acryloxyalkyl group, a methacryloxyalkyl group, a vinyl group, a phenyl group, and N-β- (N-vinylbenzylamino) ethyl-γ-aminoalkyl monohydrogenhydro -Represents a group selected from a chloride group. Specific examples of the alkoxysilane adhesion promoter represented by the general formula include γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and N-β. -(N-vinylpentylamino) ethyl-γ-aminopropyltrimethoxysilane monohydrogenhydro chloride, phenyltrimethoxysilane and vinyltrimethoxysilane.

  The adhesion promoter is preferably added in the range of 0.5 to 15 parts by weight with respect to 100 parts by weight of the silica powder. It is desirable that the adhesion promoter is added at the same time when the silica powder and the polydiorganosiloxane polymer are mixed.

  The blending ratio of silica powder and polyorganosiloxane polymer used in the above-mentioned (1) powdery silicone compound is the silica powder when the total amount of silica powder and polyorganosiloxane polymer is 100% by weight. Is preferably selected in the range of 10 to 90% by weight and the polyorganosiloxane polymer in the range of 90 to 10% by weight. When the amount of the silica powder is less than 10% by weight, it becomes difficult to support the polyorganosiloxane polymer, and it is difficult to form a smooth powder. When the amount exceeds 90% by weight, the amount of the polyorganosiloxane polymer is small. There is a tendency that the appearance defect of the molded product is likely to occur due to being too small. Among the above blending ratios, silica powder 20 to 80% by weight and polyorganosiloxane polymer 80 to 20% by weight are preferable, and further silica powder 20 to 50% by weight and polyorganosiloxane polymer 80 to 50% by weight are preferable. preferable. Here, the amount of the silica powder includes the amount of the surface treatment agent when the surface treatment is performed.

  The (2) branched silicone compound as the silicone compound (E-2) is a branched silicone compound having a branched structure in the main chain and an aromatic group bonded to silicon, but its weight average molecular weight is 2 The range is preferably from 3,000 to 50,000, more preferably from 3,000 to 30,000. Examples of the aromatic group include a phenyl group and a naphthyl group, and among them, a phenyl group is preferable. Further, the amount of the phenyl group in the (2) branched silicone compound is preferably 40 mol% or more. (2) The branched silicone compound is produced, for example, by the methods described in JP-A-11-140294, JP-A-10-139964, and JP-A-11-217494.

  In the resin composition of the present invention, when (2) a branched silicone compound is used as the silicone compound (E-2), 0.5 to 10 parts per 100 parts by weight of the aromatic polycarbonate (A). Part by weight, preferably 0.8 to 5 parts by weight, more preferably 1.0 to 3 parts by weight. When the amount is less than 0.5 part by weight, the combustibility is insufficient. When the amount exceeds 10 parts by weight, the appearance and the elastic modulus of the molded product tend to decrease, and the flame retardancy tends to be insufficient. There is.

  The silicone compound containing a mixture of (3) aromatic group-containing cyclic polyorganosiloxane and aromatic group-containing linear polyorganosiloxane as the silicone compound (E-2) is a straight chain of the following general formula (A) And a mixture of the cyclic polyorganosiloxane of the general formula (B). Among them, the compound of the general formula (B) is 5 with respect to the total amount of the compounds of the general formulas (A) and (B). It is preferred that the mixture be -95% by weight, preferably 10-50% by weight.

In the general formulas (A) and (B), n ₁ is an integer of 2 or more, and n ₂ is an integer of 3 or more. R ^e is a monovalent hydrocarbon group containing an aromatic group having 6 to 20 carbon atoms, and R ^f is a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. R ^g and R ^h are each independently a hydrogen atom or a triorganosilyl group.
In formula (A) and (B), the monovalent hydrocarbon group containing an aromatic group having 6 to 20 carbon atoms represented by R ^e, a benzyl group, aralkyl groups such as phenethyl groups, tolyl groups, An aromatic hydrocarbon group substituted with an alkyl group such as a xylyl group, an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, and a biphenyl group is mentioned, among which an aromatic hydrocarbon group is preferable, and further, a phenyl group is preferable.

In the general formulas (A) and (B), the monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by R ^f includes a methyl group, an ethyl group, an isopropyl group, a butyl group, a hexyl group, and a decyl group. And an alkenyl group such as a vinyl group and an allyl group, and a cycloalkyl group such as a cyclohexyl group. Among them, an alkyl group is preferable, and a methyl group is particularly preferable.

(3) A silicone compound containing an aromatic group-containing cyclic polyorganosiloxane and a linear polyorganosiloxane can be produced by a known method as described in JP-A-2002-53746. For example, by hydrolyzing an aromatic group-containing dichlorosilane (R ^h R ^g SiCl ₂ ) or an aromatic group-containing dialkoxysilane (R ^h R ^g Si (OR ′) ² ), the terminal is a silanol group. A mixture of a certain linear polyorganosiloxane (A) and cyclic polyorganosiloxane (B) is obtained. R ′ is an alkyl group.

When the above (3) silicone compound is blended in the resin composition of the present invention, 0.5 to 10 parts by weight, more preferably 1.0 to 100 parts by weight with respect to 100 parts by weight of the aromatic polycarbonate resin (A). It is preferable to blend 5.0 parts by weight. In the case of 0.5 parts by weight or less, the combustibility is insufficient, and in the case of exceeding 10 parts by weight, the appearance of the molded product and the elastic modulus are likely to decrease, and the flame retardancy is also insufficient.
By blending the above-mentioned specific flame retardants (E-1) to (E-3) with the resin composition of the present invention, there is an advantage that not only flame retardancy but also light resistance is improved.

  The resin composition of the present invention preferably further contains polytetrafluoroethylene (F) as an anti-dripping agent. Polytetrafluoroethylene (F) is a polytetrafluoroethylene having a fibril-forming ability, in particular, because it tends to disperse in the polymer and to form a fibrous structure by bonding the polymers together. Is preferred. Polytetrafluoroethylene having fibril-forming ability is classified as type 3 according to the ASTM standard. Examples of polytetrafluoroethylene having fibril-forming ability include Teflon (registered trademark) 6J manufactured by Mitsui DuPont Fluorochemical Co., Ltd. and polyflon manufactured by Daikin Chemical Industries, Ltd. Moreover, as an aqueous dispersion of polytetrafluoroethylene, Teflon (registered trademark) 30J manufactured by Mitsui DuPont Fluorochemical Co., Ltd., Fullon D-1 manufactured by Daikin Chemical Industries, Ltd., and a vinyl monomer are polymerized. And a polytetrafluoroethylene polymer having a multilayer structure such as METABRENE A-3800 manufactured by Mitsubishi Rayon Co., Ltd.

  When polytetrafluoroethylene (F) is blended in the resin composition of the present invention, 0.01 to 1 part by weight, and further 0.02 to 0, based on 100 parts by weight of the aromatic polycarbonate resin (A). It is preferable to add 0.8 part by weight, particularly 0.05 to 0.6 part by weight. If the amount of polytetrafluoroethylene (F) is less than 0.01 parts by weight, the flame retardancy is insufficient, and if it exceeds 1 part by weight, the appearance of the molded product tends to deteriorate.

  In the resin composition of the present invention, in addition to the components (A) to (F) described above, as long as the purpose and the necessity are not impaired, the effects of the present invention can be maintained. Agents, impact modifiers, pigments, dyes, lubricants, mold release agents, additives such as slidability improvers, reinforcing materials such as glass fibers and glass flakes, whiskers such as potassium titanate and aluminum borate, or aromatics A thermoplastic resin other than polycarbonate can be blended.

  The resin composition of the present invention may further contain an ultraviolet absorber for the purpose of improving the ultraviolet resistance. Examples of the ultraviolet absorber blended in the present invention include benzophenone series, benzotriazole series, phenyl salicylate series, and hindered amine series compounds. In particular, by blending an ultraviolet absorber with a 5% weight loss temperature of 300 ° C. or higher, molding defects such as injection molding and extrusion molding, such as mold deposit, silver streak, and roll contamination, are suppressed, and molding is performed. The light resistance during use of the product can be improved. As an ultraviolet absorber having a 5% weight loss temperature of 300 ° C. or more, for example, trade name: Asahi Denka Kogyo Co., Ltd .: LA-31 (2,2-methylenebis (4- (1,1,3,3-tetra Methylbutyl) -6- (2H-benzotriazol-2-yl) phenol) and the like.

  In the resin composition of the present invention, as thermoplastic resin components other than the aromatic polycarbonate resin (A), polyester resins such as polybutylene terephthalate and polyethylene terephthalate, polyamide resins, styrene resins such as HIPS resin and ABS resin, You may contain thermoplastic resins, such as polyolefin resins, such as polyethylene and a polypropylene, as needed. The blending amount of the thermoplastic resin other than the aromatic polycarbonate resin (A) is 40% by weight or less based on the total amount of the aromatic polycarbonate resin (A) and the thermoplastic resin other than the aromatic polycarbonate resin (A). Furthermore, 30% by weight or less is preferable.

  The method for producing the resin composition of the present invention is not particularly limited. For example, (1) an aromatic polycarbonate resin (A), titanium oxide (B), and a benzoxazole-based compound (C) are necessary. (2) Aromatic polycarbonate resin (D), non-halogen flame retardant (E), polytetrafluoroethylene (F) and other additives that are used in accordance with the melt, After melt-kneading A) and titanium oxide (B) in advance, benzoxazole-based compound (C) and, if necessary, antioxidant (D), non-halogen flame retardant (E), polytetrafluoroethylene (F), The method of mix | blending other additives and melt-kneading is mentioned.

  The polycarbonate resin composition of the present invention can be used as a molding material for various molded products, but has a high light reflectance of, for example, 94% or more, and is excellent in light shielding properties and ultraviolet resistance. In addition, it is useful as a molded product for light reflection applications such as peripheral members thereof.

  The production method of the light reflecting plate which is the main aspect of the molded product of the present invention is not particularly limited, and injection molding with an injection molding machine, sheet molding with an extrusion molding machine, or injection by shaping the obtained sheet. A known thermoplastic resin molding method such as a method of injection molding and integration after insertion into a mold of a molding machine is employed.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to the following examples, unless the summary is exceeded. The raw materials used in the following examples are as follows.

[raw materials]
(A) Aromatic polycarbonate resin: Poly-4,4-isopropylidene diphenyl carbonate (“Iupilon (registered trademark) S-3000” manufactured by Mitsubishi Engineering Plastics Co., Ltd., viscosity average molecular weight 21,000, “PC” in the table) .)
(B) Titanium oxide: 3% hydrogen polysiloxane (organic treatment agent) was blended with titanium dioxide not subjected to inorganic treatment, and the temperature was raised to 120 ° C. with stirring in a super mixer and held for 1 hour. And then obtained by taking out at a reduced temperature ("ST6433TDA" rutile type manufactured by Resino Color Co., Ltd., average particle size 0.22μ)

(C) Optical brightener (C-1) benzoxazole-based compound: 2,5-bis [5′-t-butylbenzoxazolyl (2)] thiophene (“UvitexOB” manufactured by Ciba Geigy)
(C-2) Coumarin compound: 3-phenyl-7- (2H-naphtho (1,2-d) -triazol-2-yl) coumarin (“Leucopure EGM” manufactured by Ciba Specialty Chemicals Co., Ltd.)

(D) Antioxidant (D-1-1) Phosphite ester compound 1: Cyclic neopentanetetraylbis (2,6-di-tert-butyl-4-methylphenyl) diphosphite (Asahi Denka Kogyo) "ADK STAB PEP-36" manufactured by Co., Ltd.)
(D-1-2) Phosphite ester compound 2: Tris (2,4-ditertiary butylphenyl) phosphite (“ADK STAB 2112” manufactured by Asahi Denka Kogyo Co., Ltd.)

(D-2-1) Hindered phenolic compound 1: pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) (Irganox manufactured by Ciba Specialty Chemicals Co., Ltd.) 1010 ")
(D-2-2) Hindered phenol compound 2: n-octadecyl-β- (4-hydroxy-3,5-di-t-butylphenyl) propionate (“Irganox 1076” manufactured by Ciba Specialty Chemicals) ")

(E) Flame Retardant Flame Retardant 1: Powdered silicone compound (Toray Fill F202 manufactured by Toray Dow Corning Silicone Co., Ltd.) having a viscosity of 60000 cSt supported on silica powder, polydimethylsiloxane content 60 weight %)
Flame retardant 2: Branched silicone compound having a main chain having a branched structure and a phenyl group bonded to a silicon atom (“X-40-9805” manufactured by Shin-Etsu Chemical Co., Ltd.)
Flame Retardant 3: Resorcin Dixyl Phosphate (In General Formula (6), R _{9 to} R ₁₂ are xylyl groups, l is a compound having about 1 to 1.2, “PX200” manufactured by Daihachi Chemical Industry Co., Ltd.)

(F) Anti-dripping agent: “Polyflon F-201L” manufactured by Polytetrafluoroethylene Daikin Co., Ltd. having fibril forming ability)
(G) Impact modifier: butadiene core / acrylic shell (Rohm & Haas Co., Ltd. "Paraloid EXL2603")

[Method for evaluating molded products]
(1) Impact strength An Izod impact test piece was molded under a cylinder temperature of 280 ° C, and the impact strength was measured in accordance with ATSM D256.
(2) Hue evaluation A spectroscopic color difference meter “SE-2000, C light source / reflection” manufactured by Nippon Denshoku Industries Co., Ltd. was used, and a square plate having a molded product thickness of 2 mm was molded as a test piece to obtain an initial hue (YI). Was evaluated.

(3) Light resistance test In the same manner as the evaluation of the initial hue, a square plate having a thickness of 2 mm was molded as a test piece, and this test piece was measured using a metal ring weatherometer M6T manufactured by Suga Test Instruments Co., Ltd. After irradiation for 100 hours under conditions of a panel temperature of 60 ° C., a humidity of 50%, and an irradiance of 0.75 KW / m ² , the hue (YI) of the test piece was evaluated. The values in the table indicate that the closer to the initial hue value, the better the light resistance.

(4) Flammability A 1.6 mm-thick test piece was molded and subjected to a vertical combustion test in accordance with UL94 to evaluate the flammability.
(5) Appearance evaluation A square plate having a molded product thickness of 2 mm was molded as a test piece, and the appearance of the test piece was visually determined. In the table, the case where no silver was generated was marked as ◯, the case where silver was slightly generated was marked as Δ, and the case where a large amount of silver was generated was marked as x.

[Examples 1 to 13 and Comparative Examples 1 to 4]
Blend the aromatic polycarbonate resin, titanium oxide, fluorescent brightener, antioxidant, flame retardant, anti-dripping agent and impact modifier so that the blending amounts shown in Table 1 and Table 2 are obtained, and tumbler for 20 minutes. After mixing, the mixture was melt-kneaded using a 30 mm twin screw extruder at a cylinder temperature of 270 ° C. to obtain pellets of the resin composition. Using the obtained pellets, various test pieces were molded at a cylinder temperature of 280 ° C. and evaluated. The evaluation results are shown in Tables 1 and 2.

(1) Comparing Examples 1 and 2 with Comparative Examples 1 and 2, when a benzothiazole compound having a thiophene skeleton is blended, a benzothiazole compound is not blended (Comparative Example 1) and a coumarin compound Compared to the case where (Comparative Example 2) is blended, the light resistance is excellent. Even when a benzothiazole-based compound having a thiophene skeleton is blended, the light resistance is inferior when 0.2 parts by weight is blended (Comparative Example 3).
(2) When Example 1 and Examples 3-10 are compared, it turns out that an external appearance is excellent by mix | blending antioxidant. Moreover, in Examples 3-7 which mix | blended (D-1-1) phosphite compound represented by General formula (2) as antioxidant, light resistance is further excellent.

Claims (11)

  3 to 50 parts by weight of titanium oxide (B) and 0.001 to 0.15 parts by weight of benzoxazole-based compound (C) having a thiophene structure per 100 parts by weight of aromatic polycarbonate resin (A) A polycarbonate-based resin composition characterized by comprising: The polycarbonate-based resin composition according to claim 1, wherein the benzoxazole-based compound (C) is a compound represented by the following general formula (1).

(In General Formula (1), R ₁ and R ₂ each independently represent an alkyl group having 1 to 10 carbon atoms, and n and m each independently represent an integer of 0 to 3)   The polycarbonate resin composition according to claim 1 or 2, wherein 0.001 to 1 part by weight of the phosphite compound (D-1) is blended with 100 parts by weight of the aromatic polycarbonate resin (A). The polycarbonate resin composition according to claim 3, wherein the phosphite compound (D-1) is a compound represented by the following general formula (2).

(In General Formula (2), R ₃ and R ₄ are each independently an alkyl group or an aryl group, and may have a substituent.)   The polycarbonate-type resin composition in any one of Claims 1-4 which mix | blends 0.001-1 weight part of hindered phenolic compounds (D-2) with respect to 100 weight part of this aromatic polycarbonate resin (A). object. The polycarbonate resin composition according to claim 5, wherein the hindered phenol compound (D-2) is a compound represented by the following general formula (5).

(In General Formula (5), R ₅ and R ₆ each independently represent an alkyl group having 1 to 10 carbon atoms, and R ₇ and R ₈ each independently represent an alkylene group having 1 to 5 carbon atoms. .)   The polycarbonate-type resin composition in any one of Claims 1-6 which mix | blend 2-20 weight part of non-halogen phosphate ester (E-1) with respect to 100 weight part of this aromatic polycarbonate resin (A).   The polycarbonate-type resin composition in any one of Claims 1-7 which mix | blends 0.5-10 weight part of silicone type compounds (E-2) with respect to 100 weight part of this aromatic polycarbonate resin (A).   The polycarbonate resin composition according to claim 8, wherein the silicone compound (E-2) is a powdery silicone compound obtained by supporting polyorganosiloxane on silica powder.   The polycarbonate-type resin composition in any one of Claims 1-9 which mix | blend polytetrafluoroethylene (F) which has a fibril formation ability.   A molded article obtained by molding the polycarbonate resin composition according to any one of claims 1 to 10.