JP6648361B2 - Light guide for vehicle lamp - Google Patents

Description

  The present invention relates to a light guide for a vehicle lamp having good hue and brightness without impairing the inherent properties of a polycarbonate resin, that is, heat resistance, mechanical strength, and the like, and without lowering light transmittance.

  In recent years, for example, for applications such as railroads such as vehicles and Shinkansen, dare to turn on the lamp even in the bright daytime, to inform oncoming vehicles and pedestrians, etc., for the purpose of dressing up Daylighting is progressing. In particular, in vehicles such as automobiles and motorcycles provided with daylights in the vicinity of headlamps and rear lamps, such demand has been increasing earlier than in Japan, mainly in Scandinavian countries. As the daylight, a light guide and a light source such as an LED provided near the light guide are provided, and for example, the one disclosed in Patent Document 1 is known.

  Until now, polymethyl methacrylate (hereinafter, referred to as PMMA) has been used as a light guide resin. However, PMMA is being replaced with a polycarbonate resin because of its high heat resistance and high mechanical strength. Have been.

  Polycarbonate resin is superior to PMMA in mechanical properties, thermal properties, and electrical properties, but is slightly inferior in light transmittance. Therefore, the light guide made of polycarbonate resin has a problem that the brightness is lower than that using the light guide made of PMMA.

  Therefore, as disclosed in Patent Documents 2 to 6, for example, a resin composition using a polycarbonate resin and another material in combination to obtain a light transmittance equal to or higher than that of PMMA and improve the brightness of the light guide Have been proposed.

  However, the resin compositions disclosed in Patent Literatures 2 to 6 cannot sufficiently satisfy recent demands for light guide materials.

JP 2013-234233 A JP-A-09-020860 JP-A-11-158364 JP 2001-215336 A JP 2004-051700 A International Publication No. 2011/083635

  The present invention provides a polycarbonate resin composition having excellent light transmittance even when molded at high temperature, without impairing properties such as heat resistance and mechanical strength inherent to the polycarbonate resin, and having high light transmittance. A light guide for a vehicle lamp which is molded, has high luminance, has small yellowness, is excellent in hue, and has excellent luminance and hue even when molded at a high temperature.

  The present inventors have conducted intensive studies in order to solve such problems, and as a result, by including a specific polyalkylene glycol (B) and a specific phosphite compound in a polycarbonate resin, the light transmittance was improved. It has been found that a light guide for a vehicle lamp having a good hue and a good luminance can be obtained without a decrease in the light intensity, and the present invention has been completed.

（式中、Ｒ^１は、炭素数１〜２０のアルキル基又はアルキル基で置換されていてもよいアリール基を示し、ａは、０〜３の整数を示す） That is, the present invention relates to 100 parts by weight of the polycarbonate resin (A) and 0.005 to 3.0 parts by weight of a polyalkylene glycol (B) represented by the following general formula (1) and having a weight average molecular weight of 1,000 to 4,000. And a resin composition containing 0.005 to 1.0 parts by weight of a phosphite compound (C) represented by the following general formula (2). Is what you do.
General formula (1):
_{HO- (CH 2 CH 2 O)} m (CH 2 CH (CH 3) O) n-H (4)
(In the formula, m and n each independently represent an integer of 3 to 60, and m + n represents an integer of 8 to 90.)
General formula (2):

(Wherein, R ¹ represents an alkyl group having 1 to 20 carbon atoms or an aryl group optionally substituted with an alkyl group, and a represents an integer of 0 to 3)

  The light guide for a vehicle lamp in the present invention is formed by molding a polycarbonate resin composition, and the heat resistance, mechanical strength, and other properties inherent to the polycarbonate resin are not impaired, the light transmittance is high, and at high temperatures. Even when molded, it has excellent light transmittance. Therefore, even for a thin light guide having a thickness of about 0.3 mm, for example, the hue changes and the appearance is not deteriorated, and the resin itself is hardly deteriorated through high-temperature molding. high.

  Hereinafter, embodiments will be described in detail. However, an unnecessary detailed description may be omitted. For example, a detailed description of a well-known item or a redundant description of substantially the same configuration may be omitted. This is to prevent the following description from being unnecessarily redundant and to facilitate understanding by those skilled in the art.

  It should be noted that the inventors provide the following description for those skilled in the art to fully understand the present invention, and are not intended to limit the claimed subject matter.

  The vehicle lamp light guide (daytime light guide) of the present invention is a daylight provided near a vehicle headlight such as a headlamp, an auxiliary headlight such as a fog lamp, or various vehicle lamps such as a daytime running lamp. And is used as a lighting device that is turned on using a light source such as an LED provided in the vicinity of the light guide and exhibits high visibility.

  The polycarbonate resin composition used in the present invention is obtained by blending a specific polyalkylene glycol (B) and a specific phosphite compound (C) with a polycarbonate resin (A). In addition, you may mix | blend other components with the polycarbonate resin composition used by this invention as needed.

  The polycarbonate resin (A) is a polymer obtained by a phosgene method of reacting various dihydroxydiaryl compounds with phosgene, or a transesterification method of reacting a dihydroxydiaryl compound with a carbonate such as diphenyl carbonate. A representative example is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).

  Examples of the dihydroxydiaryl compound include, in addition to bisphenol A, 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, 2,2- Bis (hydroxyaryl) alkanes such as bis (4-hydroxy-3,5-dichlorophenyl) propane; Bis (hydroxyaryl) cycloalkanes such as -bis (4-hydroxyphenyl) cyclopentane and 1,1-bis (4-hydroxyphenyl) cyclohexane; 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 4,3'-dimethyldiphenyl ether; dihydroxy diaryl sulfides such as 4,4'-dihydroxy diphenyl sulfide; 4,4'-dihydroxy diphenyl sulphoxide, 4,4'-dihydroxy-3,3'-dimethyl Dihydroxydiarylsulfoxides such as diphenylsulfoxide; dihydroxydiarylsulfones such as 4,4'-dihydroxydiphenylsulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone; These may be used alone or as a mixture of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be used as a mixture.

  Further, the dihydroxydiaryl compound may be used in combination with, for example, a trivalent or higher phenol compound shown below.

  Examples of the trivalent or higher phenol compound include phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene, 2,4,6-dimethyl-2,4,6 -Tri- (4-hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2- Bis- [4,4- (4,4′-dihydroxydiphenyl) -cyclohexyl] -propane;

  The viscosity average molecular weight of the polycarbonate resin (A) is preferably 10,000 to 100,000, more preferably 12,000 to 30,000. When producing such a polycarbonate resin (A), a molecular weight regulator, a catalyst and the like can be used as required.

The polyalkylene glycol (B) is represented by the following general formula (1).
General formula (1):
_{HO- (CH 2 CH 2 O)} m (CH 2 CH (CH 3) O) n-H (4)
(In the formula, m and n each independently represent an integer of 3 to 60, and m + n represents an integer of 8 to 90.)

  Further, since the polyalkylene glycol (B) represented by the general formula (1) has moderate lipophilicity and is excellent in compatibility with the polycarbonate resin (A), the polyalkylene glycol (B) is used. The transparency of the molded product obtained from the blended polycarbonate resin composition is also improved.

  Furthermore, by blending the polyalkylene glycol (B) represented by the general formula (1), it is possible to suppress the occurrence of unnecessarily high shearing heat when molding the polycarbonate resin composition. Since release properties can be imparted to the polycarbonate resin composition, it is not necessary to separately add a release agent such as a polyorganosiloxane compound.

  The weight average molecular weight of the polyalkylene glycol (B) is preferably from 1,000 to 4,000. If the weight average molecular weight of the polyalkylene glycol (B) is less than 1,000, a sufficient effect of improving light transmittance may not be expected. Conversely, if the weight average molecular weight exceeds 4,000, light transmittance is reduced. Clouding rate may increase.

  Examples of the commercially available polyalkylene glycol (B) include, for example, Unilube 50DE-25 (weight average molecular weight 1750) manufactured by NOF Corporation, which is a modified glycol composed of an ethylene glycol unit and a propylene glycol unit. Can be

  The amount of the polyalkylene glycol (B) is 0.005 to 3.0 parts by weight, 0.1 to 2.0 parts by weight, and further 0.5 to 1 part by weight based on 100 parts by weight of the polycarbonate resin (A). It is preferably 0.5 parts by weight. When the amount of the polyalkylene glycol (B) is less than 0.005 parts by weight, the effect of improving the light transmittance and the hue is insufficient, and when the amount exceeds 3.0 parts by weight, the light transmittance is insufficient. And the fogging rate increases.

  The polycarbonate resin composition used in the present invention includes, together with the specific polyalkylene glycol (B) represented by the general formula (1), a phosphite compound represented by the following general formula (2) (C) is blended. As described above, by simultaneously blending the specific polyalkylene glycol (B) and the specific phosphite compound (C), the properties such as the heat resistance, mechanical strength, and the like inherent to the polycarbonate resin (A) are obtained. A polycarbonate resin composition having improved light transmittance without being damaged can be obtained.

General formula (2):

（式中、Ｒ^１は、炭素数１〜２０のアルキル基又はアルキル基で置換されていてもよいアリール基を示し、ａは、０〜３の整数を示す）

(Wherein, R ¹ represents an alkyl group having 1 to 20 carbon atoms or an aryl group optionally substituted with an alkyl group, and a represents an integer of 0 to 3)

In the general formula (2), R ¹ is an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms.

  Examples of the compound represented by the general formula (2) include triphenyl phosphite, tricresyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, trisnonyl phenyl phosphite and the like. Can be Among these, tris (2,4-di-t-butylphenyl) phosphite is particularly preferable. For example, Irgafos 168 manufactured by BASF (“Irgafos” is a registered trademark of BSF SF Societas Europea) is commercially available. Is available at

The polycarbonate resin composition used in the present invention is obtained by blending a specific polyalkylene glycol (B) and a specific phosphite compound (C) with a polycarbonate resin (A). And a compound (D) represented by the general formula (3) or (4).
General formula (3):

（式中、Ｒ^２、Ｒ^３、Ｒ^５及びＲ^６は、それぞれ独立して、水素原子、炭素数１〜８のアルキル基、炭素数５〜８のシクロアルキル基、炭素数６〜１２のアルキルシクロアルキル基、炭素数７〜１２のアラルキル基又はフェニル基を示す。Ｒ^４は、水素原子又は炭素数１〜８のアルキル基を示す。Ｘは、単結合、硫黄原子又は式：−ＣＨＲ^７−（ここで、Ｒ^７は、水素原子、炭素数１〜８のアルキル基又は炭素数５〜８のシクロアルキル基を示す）で表される基を示す。Ａは、炭素数１〜８のアルキレン基又は式：＊−ＣＯＲ^８−（ここで、Ｒ^８は、単結合又は炭素数１〜８のアルキレン基を示し、＊は、酸素側の結合手であることを示す）で表される基を示す。Ｙ及びＺは、いずれか一方がヒドロキシル基、炭素数１〜８のアルコキシ基又は炭素数７〜１２のアラルキルオキシ基を示し、もう一方が水素原子又は炭素数１〜８のアルキル基を示す）

(Wherein, 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, Represents an alkylcycloalkyl group, an aralkyl group having 7 to 12 carbon atoms or a phenyl group, R 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 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), and A represents 1 to 8 carbon atoms. alkylene group or the formula: * - COR 8 - ^(wherein, R ⁸ represents a single bond or an alkylene group having 1 to 8 carbon atoms, * indicates a bond to the oxygen side) are represented by Y or Z is one of a hydroxyl group and an alcohol having 1 to 8 carbon atoms. Represents an xy group 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)

In the general formula (3), R ² , R ³ , R ⁵ and R ⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, and a carbon atom having 6 carbon atoms. An alkylcycloalkyl group of 7 to 12, an aralkyl group of 7 to 12 carbon atoms or a phenyl group.

  Here, examples of the alkyl group having 1 to 8 carbon atoms include 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 and a t-butyl group. Group, t-pentyl group, i-octyl group, t-octyl group, 2-ethylhexyl group and the like. Examples of the cycloalkyl group having 5 to 8 carbon atoms include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the alkylcycloalkyl group having 6 to 12 carbon atoms include a 1-methylcyclopentyl group, a 1-methylcyclohexyl group, and a 1-methyl-4-i-propylcyclohexyl group. Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, an α-methylbenzyl group, and an α, α-dimethylbenzyl group.

Preferably, R ² , R ³ and R ⁵ are 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. . In particular, R ² and R ⁵ are preferably each independently a t-alkyl group such as a t-butyl group, a t-pentyl group, a t-octyl group, a cyclohexyl group, or a 1-methylcyclohexyl group. In particular, R ³ is a carbon number 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, and a t-pentyl group. It is preferably an alkyl group of 1 to 5, more preferably a methyl group, a t-butyl group or a t-pentyl group.

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 is preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group. And n-butyl group, i-butyl group, sec-butyl group, t-butyl group, t-pentyl group and the like.

In the general formula (3), R ⁴ 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 alkyl groups exemplified in the description of R ² , R ³ , R ⁵ and R ⁶ . Particularly, 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.

In the general formula (3), X represents a single bond, a sulfur atom, or a group represented by the formula: —CHR ⁷ —. Here, R ⁷ in the formula: —CHR 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 alkyl groups and cycloalkyl groups exemplified in the description of R ² , R ³ , R ^5, and R ⁶ , respectively. Can be In particular, X is 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. Preferably, it is a single bond.

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

In the general formula (3), 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 a 1 to 1 carbon atom. 8 represents an alkyl group. 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 alkyl groups exemplified in the description of R ² , R ³ , R ⁵ and R ⁶ .

  As the compound represented by the general formula (3), for example, 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4-hydroxy-5-t-butylphenyl) Propoxy] dibenzo [d, f] [1,3,2] dioxaphosphepin, 6- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propoxy] -2,4,8 , 10-Tetra-t-butyldibenzo [d, f] [1,3,2] dioxaphosphepin, 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] dioxaphosphine, 6- [3- (3,5-di-t -Butyl-4-hydroxyphenyl) propionyloxy] -4,8-di-t-butyl-2, 0-dimethyl -12H- dibenzo [d, g] [1,3,2] dioxaphosphocin, and the like. Among these, particularly when the obtained polycarbonate resin composition is used in a field where optical characteristics are required, 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4) is used. -Hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1,3,2] dioxaphosphepin is suitable. For example, Sumilizer GP (“Sumilyzer”) manufactured by Sumitomo Chemical Co., Ltd. Is commercially available as a registered trademark).

In addition to the compound represented by the general formula (3), a compound represented by the general formula (4) is preferable.
General formula (4):

（式中、Ｒ^９及びＲ^１０は、それぞれ独立して、炭素数１〜２０のアルキル基又はアルキル基で置換されていてもよいアリール基を示し、ｂ及びｃは、それぞれ独立して、０〜３の整数を示す。）

(Wherein, R ⁹ and R ¹⁰ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group optionally substituted with an alkyl group, and b and c each independently represent 0 Represents an integer of 3 to 3)

  As the compound represented by the general formula (4), for example, ADK STAB PEP-36 (“ADK STAB” is a registered trademark) available from ADEKA Corporation is commercially available.

  The amount of the phosphite compound (C) is 0.005 to 1.0 part by weight, 0.01 to 0.5 part by weight, and more preferably 0.1 to 0.5 part by weight based on 100 parts by weight of the polycarbonate resin (A). It is preferably from 0.2 to 0.1 part by weight. When the amount of the phosphite compound (C) is less than 0.005 parts by weight, the effect of improving the light transmittance and the hue is insufficient, and when the amount exceeds 1.0 part by weight, The effect of improving light transmittance and hue is insufficient.

  When the phosphite compound (C) and the compound (D) are used in combination, the amount of the phosphite compound (C) is 0.01 to 0 with respect to 100 parts by weight of the polycarbonate resin (A). 0.5 part by weight, and the amount of compound (D) is preferably 0.01 to 0.5 part by weight. Furthermore, it is preferable that the amount of the phosphite compound (C) is 0.02 to 0.05 part by weight, and the amount of the compound (D) is 0.02 to 0.05 part by weight.

  Further, the polycarbonate resin composition used in the present invention, within a range that does not impair the effects of the present invention, for example, a heat stabilizer, an antioxidant, a coloring agent, a release agent, a softener, an antistatic agent, Various additives such as an impact modifier, a polymer other than the polycarbonate resin (A), and the like may be appropriately blended.

  The method for producing the polycarbonate resin composition is not particularly limited, and the polycarbonate resin (A), the polyalkylene glycol (B), the phosphite compound (C) and the compound (D), and if necessary, the various additives For the polymers and the like other than the polycarbonate resin (A) and the like, the type and amount of each component are appropriately adjusted, and these are mixed by a known mixer such as a tumbler or a ribbon blender, or melt-kneaded by an extruder. Method.

  The light guide for a vehicle lamp of the present invention is obtained by molding the polycarbonate resin composition obtained as described above. The method for producing the light guide for a vehicle lamp is not particularly limited, and examples thereof include a method of molding a polycarbonate resin composition by a known injection molding method, a compression molding method, or the like.

  As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology according to the present invention is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, and the like are made as appropriate.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, “parts” and “%” are based on weight, respectively.

The following were used as raw materials.
1. Polycarbonate resin (A)
Polycarbonate resin Caliber 200-80 synthesized from bisphenol A and carbonyl chloride
(Trade name, manufactured by Sumika Stylon Polycarbonate Co., Ltd., “Calibur” is a registered trademark of Stylon Europe GmbH, viscosity average molecular weight: 15000, hereinafter referred to as “PC”)

2. Polyalkylene glycol (B)
Modifying glycols comprising ethylene glycol units and propylene glycol units _{HO- (CH 2 CH 2 O)} 17 (CH 2 CH (CH 3) O) 17 -H
Unilube 50DE-25
(Trade name, NOF (manufactured by Corporation), weight average molecular weight: 1750, hereinafter referred to as "compound B")

3. Phosphite compound (C)
Tris (2,4-di-t-butylphenyl) phosphite represented by the following formula

イルガフォス１６８（商品名、ＢＡＳＦ社製、以下「化合物Ｃ」という）

Irgafos 168 (trade name, manufactured by BASF, hereinafter referred to as "Compound C")

4. Compound (D)
3,9-bis (2,6-di-t-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] represented by the following formula: Undeca

アデカスタブＰＥＰ−３６（商品名、（株）ＡＤＥＫＡ製、以下「化合物Ｄ」という）

ADK STAB PEP-36 (trade name, manufactured by ADEKA Corporation, hereinafter referred to as "Compound D")

Examples 1 to 8 and Comparative Examples 1 to 5
The raw materials were put together in a tumbler at the mixing ratios shown in Tables 1 and 2 and were dry-mixed for 10 minutes. Then, using a twin-screw extruder (manufactured by Nippon Steel Works, TEX30α), The mixture was melt-kneaded at a melting temperature of 220 ° C. to obtain pellets of the polycarbonate resin composition.

  Using the obtained pellets, test pieces for evaluation were prepared according to the following method and subjected to evaluation. The results are shown in Tables 1 and 2.

(Method of preparing test pieces)
After drying the obtained pellets at 120 ° C. for 4 hours or more, using an injection molding machine (ROBOSHOT S2000i100A, manufactured by FANUC CORPORATION) at a molding temperature of 360 ° C. and a mold temperature of 80 ° C., JIS K 7139 “Plastic- A specified multi-purpose test piece A type (length 168 mm × thickness 4 mm) was prepared from “test piece”. The end face of this test piece was cut, and the cut end face was mirror-finished using a resin plate end face mirror machine (Plasticity PB-500, manufactured by Megalo Technica Co., Ltd.).

(Evaluation method of integrated transmittance)
A long light path measuring accessory is installed on a spectrophotometer (UH4150, manufactured by Hitachi, Ltd.), and a 50 W halogen lamp is used as a light source, and a light source front mask is 5.6 mm × 2.8 mm, and a sample front mask is 6.0 mm × With 2.8 mm used, the spectral transmittance in the direction of the length of 168 mm of the test piece was measured every 1 nm in the wavelength range of 380 to 780 nm. The measured spectral transmittances were integrated, and the tens place was rounded off to obtain each integrated transmittance. In addition, the integrated transmittance of 30,000 or more was evaluated as good (indicated by a circle in the table), and the integrated transmittance of less than 30,000 was evaluated as poor (indicated by a cross in the table).

(Evaluation method of yellowness)
Based on the spectral transmittance measured by the above-described method for evaluating the integrated transmittance, each yellowness was determined in a 10-degree visual field using a standard light source D65. In addition, when the yellowness was 20 or less, it was evaluated as good (shown by ○ in the table), and when it exceeded 20, it was evaluated as poor (shown by x in the table).

  The polycarbonate resin compositions of Examples 1 to 8 were obtained by adding a specific polyalkylene glycol (B) represented by the general formula (1) and a specific phosphite compound (C) to a polycarbonate resin (A). Compound (D) is compounded at a specific ratio as required. Test pieces (light guides for vehicle lamps) molded from the polycarbonate resin compositions according to these examples have high integrated transmittance and low yellowness.

  Thus, the polycarbonate resin compositions of Examples 1 to 8 have high light transmittance in the visible region without impairing the inherent heat resistance of the polycarbonate resin (A), and are stable at high temperatures in light transmittance. Also excellent in nature. A test piece (light guide for a vehicle lamp) molded from such a polycarbonate resin composition has a small yellowness and excellent hue even when molded at a high molding temperature of 360 ° C.

  In contrast, the polycarbonate resin composition of Comparative Example 1 had a small amount of the specific polyalkylene glycol (B), and the test piece molded at a high temperature had a low integrated transmittance.

  The polycarbonate resin composition of Comparative Example 2 was a case where the amount of the specific polyalkylene glycol (B) was large, but the test piece molded at a high temperature had a low integrated transmittance and a large yellowness. Was.

  The polycarbonate resin composition of Comparative Example 3 had a small amount of the specific phosphite compound (C), and the test piece molded at a high temperature had a low integrated transmittance and a large yellowness.

  The polycarbonate resin composition of Comparative Example 4 has a large amount of the specific phosphite compound (C), and a test piece molded at a high temperature has a low integrated transmittance and a large yellowness. there were.

  The test in which the polycarbonate resin composition of Comparative Example 5 did not contain the specific polyalkylene glycol (B) but used the specific phosphite-based compound (C) and the compound (D) together and was molded at a high temperature The piece had a low integrated transmittance and a large yellowness.

  As described above, the embodiments have been described as examples of the technology according to the present invention. To that end, a detailed description has been provided.

  Therefore, among the components described in the detailed description, not only components that are essential for solving the problem but also components that are not essential for solving the problem are included to illustrate the above technology. obtain. Therefore, the fact that those non-essential components are described in the detailed description should not be used to immediately determine that these non-essential components are essential.

  Further, since the above-described embodiment is intended to exemplify the technique of the present invention, various changes, replacements, additions, omissions, and the like can be made within the scope of the claims or the equivalents thereof.

  The vehicle lamp light guide of the present invention is provided near various vehicle lamps such as a vehicle headlight such as a headlamp, an auxiliary headlight such as a fog lamp, or a daytime running lamp, and has a heat resistance inherent to the polycarbonate resin. It has high light transmittance without impairing the properties such as mechanical strength and the like, and also has excellent light transmittance even when molded at a high temperature, and has extremely high industrial utility value.

Claims (6)

With respect to 100 parts by weight of the polycarbonate resin (A), 0.005 to 3.0 parts by weight of a polyalkylene glycol (B) represented by the following general formula (1) having a weight average molecular weight of 1,000 to 4,000 and the following general formula (2) A light guide for a vehicle lamp, comprising a resin composition containing 0.005 to 1.0 part by weight of a phosphite compound (C) represented by the formula (1).
General formula (1):
_{HO- (CH 2 CH 2 O)} m (CH 2 CH (CH 3) O) n-H (4)
(In the formula, m and n each independently represent an integer of 3 to 60, and m + n represents an integer of 8 to 90.)
General formula (2):

(Wherein, R ¹ represents an alkyl group having 1 to 20 carbon atoms or an aryl group optionally substituted with an alkyl group, and a represents an integer of 0 to 3) The light guide for a vehicle lamp according to claim 1, further comprising a compound (D) represented by the following general formula (3) or (4).
General formula (3):

(Wherein, 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, Represents an alkylcycloalkyl group, an aralkyl group having 7 to 12 carbon atoms or a phenyl group, R 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 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), and A represents 1 to 8 carbon atoms. alkylene group or the formula: * - COR 8 - ^(wherein, R ⁸ represents a single bond or an alkylene group having 1 to 8 carbon atoms, * indicates a bond to the oxygen side) are represented by Y or Z is one of a hydroxyl group and an alcohol having 1 to 8 carbon atoms. Represents an xy group 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)
General formula (4):

(In the formula, R ⁹ and R ¹⁰ represent 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 represent an integer of 0 to 3.)   The light guide for a vehicle lamp according to claim 1, wherein the phosphite compound (C) represented by the general formula (2) is tris (2,4-di-t-butylphenyl) phosphite.   Compound (D) represented by the general formula (3) is 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4-hydroxy-5-t-butylphenyl) 3. The light guide for a vehicle lamp according to claim 2, wherein the light guide is propoxy] dibenzo [d, f] [1,3,2] dioxaphosphepin.   The compound (D) represented by the general formula (4) is 3,9-bis (2,6-di-t-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9 3. The light guide for a vehicle lamp according to claim 2, wherein the light guide is diphosphaspiro [5,5] undecane.   The amount of the phosphite-based compound (C) is 0.01 to 0.5 part by weight, and the amount of the compound (D) is 0.01 to 100 parts by weight of the polycarbonate resin (A). The light guide for a vehicle lamp according to claim 2, wherein the amount is 0.5 to 0.5 parts by weight.