JP2017204412A - Light guide for vehicle lamp - Google Patents

Abstract

CONSTITUTION: A light guide for a vehicle lamp includes a resin composition containing 0.005 to 3.0 pts.wt. of a specific polyalkylene glycol (B) and 0.005 to 1.0 pts.wt. of a specific phosphite compound (C) based on 100 pts.wt. of a polycarbonate resin (A).EFFECT: The light guide for the vehicle lamp of the present invention is excellent in luminance, light transmittance and hue stability in particular, without impairing the original characteristics of polycarbonate resin, that is, mechanical properties and heat resistance. Therefore, even in molding process of a light guide plate of thin type (about 0.3 mm thick), the hue is not changed and the resin itself is not deteriorated.SELECTED DRAWING: None

Description

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

  In recent years, for example, for purposes such as for vehicles and trains such as Shinkansen, the lamp is lit in bright hours during the day to inform oncoming vehicles and pedestrians, and for dress-up purposes. Daylighting is progressing. In particular, demand for vehicles such as automobiles and motorcycles equipped with daylights in the vicinity of headlamps and rear lamps has been increasing from an earlier stage than Japan, mainly in the Nordic countries. As this daylight, a light guide and a light source such as an LED provided in the vicinity thereof are provided. For example, a light source disclosed in Patent Document 1 is known.

  Until now, polymethylmethacrylate (hereinafter referred to as PMMA) has been used as a light guide resin, but replacement of PMMA with polycarbonate resin has been promoted because of its high heat resistance and high mechanical strength. It has been.

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

  Therefore, as disclosed in, for example, Patent Documents 2 to 6, a resin composition in which a polycarbonate resin and another material are used together in order to obtain a light transmittance equal to or higher than that of PMMA and improve the brightness of the light guide. Various proposals have been made.

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

JP 2013-234233 A Japanese Patent Laid-Open No. 09-020860 JP-A-11-158364 JP 2001-215336 A JP 2004-051700 A International Publication No. 2011/088335

  The present invention provides a polycarbonate resin composition that does not impair the properties such as heat resistance and mechanical strength inherent to the polycarbonate resin, has high light transmittance, and has excellent light transmittance even when molded at a high temperature. Provided is a light guide for a vehicle lamp which is molded, has high brightness, low yellowness, excellent hue, and excellent brightness and hue even when molded at a high temperature.

  As a result of intensive studies to solve the problems, the present inventors have made the polycarbonate resin contain a specific polyalkylene glycol (B) and a specific phosphite compound, thereby increasing the light transmittance. The present invention has been completed by finding that a light guide for a vehicle lamp having a good hue and brightness can be obtained.

（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 is represented by the following general formula (1) with respect to 100 parts by weight of the polycarbonate resin (A), and 0.005 to 3.0 parts by weight of a polyalkylene glycol (B) having a weight average molecular weight of 1000 to 4000. And a light guide for vehicle lamps comprising a resin composition containing 0.005 to 1.0 parts by weight of a phosphite compound (C) represented by the following general formula (2): To 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):

(In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be 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, the properties such as heat resistance and mechanical strength inherent to the polycarbonate resin are not impaired, the light transmittance is high, and at a high temperature. Even when it is molded, it has excellent light transmittance. Therefore, even if it is a thin light guide with a thickness of about 0.3 mm, for example, the hue changes and the appearance deteriorates, and the resin itself is less likely to deteriorate through high-temperature molding, and the industrial utility value is extremely high. high.

  Hereinafter, embodiments will be described in detail. However, more detailed explanation than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The inventors provide the following explanation for those skilled in the art to fully understand the present invention, and are not intended to limit the claimed subject matter.

  The light guide for vehicle lamps (daytime light guide) of the present invention is lit in the daytime provided near various vehicle lamps such as vehicle headlamps such as headlamps, auxiliary headlamps such as fog lamps, and daytime running lamps. It is used as a lighting fixture that is turned on using a light source such as an LED provided near 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 another component with the polycarbonate resin composition used by this invention as needed.

  The polycarbonate resin (A) is a polymer obtained by a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate are reacted. A typical example is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).

  As the dihydroxydiaryl compound, in addition to bisphenol A, for example, 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'-dihydroxydiphenyl sulfide; 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyl Dihydroxy diaryl sulfoxides such as diphenyl sulfoxide; dihydroxy diaryl sulfones such as 4,4′-dihydroxydiphenyl sulfone and 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone; These may be used alone or in admixture of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4′-dihydroxydiphenyl, and the like may be mixed and used.

  Furthermore, you may mix and use the said dihydroxy diaryl compound and the trivalent or more phenol compound shown below, for example.

  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 and the like.

  The viscosity average molecular weight of the polycarbonate resin (A) is preferably 10,000 to 100,000, more preferably 12,000 to 30,000. In addition, when manufacturing such a polycarbonate resin (A), a molecular weight regulator, a catalyst, etc. can be used as needed.

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 an appropriate lipophilicity, it is excellent in compatibility with the polycarbonate resin (A). 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), when molding the polycarbonate resin composition, it is possible to suppress generation of shear heat more than necessary, Since release properties can also be imparted to the polycarbonate resin composition, for example, a release agent such as a polyorganosiloxane compound need not be added separately.

  The polyalkylene glycol (B) preferably has a weight average molecular weight of 1000 to 4000. When the weight average molecular weight of the polyalkylene glycol (B) is less than 1000, there is a possibility that a sufficient effect of improving the light transmittance may not be expected. Conversely, when the weight average molecular weight exceeds 4000, the light transmittance decreases. The fogging rate may increase.

  Examples of the commercially available polyalkylene glycol (B) include 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. It is done.

  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 with respect to 100 parts by weight of the polycarbonate resin (A). .5 parts by weight is preferred. When the amount of the polyalkylene glycol (B) is less than 0.005 parts by weight, the effect of improving the light transmittance and hue is insufficient, and conversely, when the amount exceeds 3.0 parts by weight, the light transmittance Decreases and the fogging rate increases.

  The polycarbonate resin composition used in the present invention includes a phosphite compound represented by the following general formula (2) together with the specific polyalkylene glycol (B) represented by the general formula (1). (C) is blended. Thus, by simultaneously blending the specific polyalkylene glycol (B) and the specific phosphite compound (C), the polycarbonate resin (A) has inherent properties such as heat resistance and mechanical strength. A polycarbonate resin composition with improved light transmittance is obtained without damage.

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）

(In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be 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, and trisnonylphenyl phosphite. It is done. Among these, tris (2,4-di-t-butylphenyl) phosphite is particularly suitable. For example, Irgaphos 168 manufactured by BASF ("Irgaphos" is a registered trademark of BISF Societas Europea) is commercially available. Is available.

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). It is preferable that the compound (D) represented by the general formula (3) or the general formula (4) is included.
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）

(In the formula, 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, or an alkyl group having 6 to 12 carbon atoms. 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 is a single bond, a sulfur atom, or a formula: —CHR; ^7- (wherein 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 a group having 1 to 8 carbon atoms. Or an alkylene group of the formula: * —COR ⁸ — (wherein R ⁸ represents a single bond or an alkylene group having 1 to 8 carbon atoms, and * represents a bond on the oxygen side). Y and Z are either a hydroxyl group or an alcohol having 1 to 8 carbon atoms. A xyl group or an aralkyloxy group having 7 to 12 carbon atoms, the other being a hydrogen atom or an alkyl group having 1 to 8 carbon atoms

In General Formula (3), 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, or 6 carbon atoms. -12 alkylcycloalkyl group, a C7-12 aralkyl group, or a phenyl group is shown.

  Here, examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, and t-butyl. 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 1-methylcyclopentyl group, 1-methylcyclohexyl group, 1-methyl-4-i-propylcyclohexyl group and the like. Examples of the aralkyl group having 7 to 12 carbon atoms include benzyl group, α-methylbenzyl group, α, α-dimethylbenzyl group and the like.

R ² , R ³ and R ⁵ are each independently preferably 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, or 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, or 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, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group. , An n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, a t-pentyl group, or the like, more preferably an alkyl group having 1 to 5 carbon atoms.

In General formula (3), R < ⁴ > shows a hydrogen atom or a C1-C8 alkyl group. As a C1-C8 alkyl group, the alkyl group illustrated by description of the said R < ² >, R < ³ >, R < ⁵ > and R < ⁶ > is mentioned, for example. In particular, 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 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. It is done. 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. It is preferably a single bond, and more preferably a single bond.

In the general formula (3), A represents an alkylene group having 1 to 8 carbon atoms or a group represented by the formula: * —COR ⁸ —. 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 is 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 which indicates the R ^8, for example, alkylene groups exemplified in the description of the 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 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 is a hydrogen atom or 1 to 1 carbon atoms. 8 represents an alkyl group. As a C1-C8 alkoxy group, a methoxy group, an ethoxy group, a propoxy group, t-butoxy group, a pentyloxy group etc. are mentioned, for example. Examples of the aralkyloxy group having 7 to 12 carbon atoms include benzyloxy group, α-methylbenzyloxy group, α, α-dimethylbenzyloxy group and the like. As a C1-C8 alkyl group, the alkyl group illustrated by description of the said R < ² >, R < ³ >, R < ⁵ > and R < ⁶ > is mentioned, for example.

  Examples of the compound represented by the general formula (3) include 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4-hydroxy-5-t-butylphenyl). Propoxy] dibenzo [d, f] [1,3,2] dioxaphosphine, 6- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propoxy] -2,4,8 , 10-Tetra-t-butyldibenzo [d, f] [1,3,2] dioxaphosphine, 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, 0-dimethyl -12H- dibenzo [d, g] [1,3,2] dioxaphosphocin, and the like. Among these, 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4) is particularly used when the obtained polycarbonate resin composition is used in a field where optical properties are required. -Hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1,3,2] dioxaphosphine is suitable, for example, Sumitizer GP ("Smilizer") 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 represents 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 represents 0 Represents an integer of ~ 3.)

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

  The amount of the phosphite ester compound (C) is 0.005 to 1.0 part by weight, 0.01 to 0.5 part by weight, and further 0.000 to 100 parts by weight of the polycarbonate resin (A). It is preferable that it is 02-0.1 weight part. When the amount of the phosphite compound (C) is less than 0.005 parts by weight, the effect of improving light transmittance and hue is insufficient, and conversely, when the amount exceeds 1.0 parts 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 parts by weight, and the amount of the compound (D) is preferably 0.01 to 0.5 parts by weight. Furthermore, the amount of the phosphite compound (C) is preferably 0.02 to 0.05 parts by weight, and the amount of the compound (D) is preferably 0.02 to 0.05 parts by weight.

  Furthermore, the polycarbonate resin composition used in the present invention is, for example, a heat stabilizer, an antioxidant, a colorant, a release agent, a softener, an antistatic agent, as long as the effects of the present invention are not impaired. Various additives such as impact modifiers, polymers 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. The polycarbonate resin (A), the polyalkylene glycol (B), the phosphite compound (C) and the compound (D), and the various additives as necessary. For polymers other than polycarbonate resin (A), etc., the type and amount of each component are adjusted as appropriate, and these are mixed in a known mixer such as a tumbler or ribbon blender, or melt kneaded in an extruder. The method of doing is mentioned.

  The vehicle lamp light guide of the present invention is formed by molding the polycarbonate resin composition obtained as described above. There is no particular limitation on the method for manufacturing the vehicle lamp light guide, and examples thereof include a method of molding a polycarbonate resin composition by a known injection molding method, compression molding method or the like.

  As described above, the embodiment has been described as an example of the technique disclosed in the present application. However, the technology according to the present invention is not limited to this, and can also be applied to embodiments in which changes, replacements, additions, omissions, etc. are made as appropriate.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on weight.

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

2. Polyalkylene glycol (B)
Modified glycol consisting of ethylene glycol unit and propylene glycol unit HO— (CH ₂ CH ₂ O) ₁₇ (CH ₂ CH (CH ₃ ) O) ₁₇ —H
UNILOVE 50DE-25
(Trade name, NOF (made by Co., Ltd., 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）

Irgaphos 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 Undeka

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 1-8 and Comparative Examples 1-5
Each raw material was collectively put into a tumbler at a blending ratio shown in Tables 1 and 2, and after dry mixing for 10 minutes, using a twin screw extruder (manufactured by Nippon Steel Works, TEX30α), Melt kneading was performed at a melting temperature of 220 ° C. to obtain pellets of a polycarbonate resin composition.

  Using the obtained pellet, according to the following method, each test specimen for evaluation was produced and used for evaluation. The results are shown in Tables 1 and 2.

(Test piece preparation method)
The obtained pellets were dried at 120 ° C. for 4 hours or more, and then an injection molding machine (manufactured by FANUC, ROBOSHOT S2000i100A) was used at a molding temperature of 360 ° C. and a mold temperature of 80 ° C. The multipurpose test piece A type (length 168 mm × thickness 4 mm) defined in “Test piece” was produced. The end face of the test piece was cut, and the cut end face was mirror-finished using a resin plate end face mirror machine (Megaro Technica Co., Ltd., Plasticity PB-500).

(Evaluation method of integrated transmittance)
A spectrophotometer (manufactured by Hitachi, Ltd., UH4150) is equipped with a long optical path measurement accessory device, using a 50 W halogen lamp as a light source, a mask before light source 5.6 mm × 2.8 mm, a mask before sample 6.0 mm × In a state where 2.8 mm was used, the spectral transmittance in the direction of 168 mm in length of the test piece was measured every 1 nm in a wavelength range of 380 to 780 nm. The measured spectral transmittance was integrated and rounded off to the nearest tenth to obtain the total transmittance. The integrated transmittance was 30000 or more as good (indicated by ◯ in the table) and less than 30000 was defective (indicated by x in the table).

(Yellowness evaluation method)
Based on the spectral transmittance measured in the evaluation method of the accumulated transmittance, each yellow degree was obtained in a 10 degree visual field using a standard light source D65. The yellowness was 20 or less as good (indicated by ◯ in the table), and when it exceeded 20, it was determined as defective (indicated by x in the table).

  In the polycarbonate resin compositions of Examples 1 to 8, the polycarbonate resin (A) contains a specific polyalkylene glycol (B) represented by the general formula (1), a specific phosphite compound (C), and The compound (D) is blended at a specific ratio as necessary. Test pieces (vehicle lamp light guides) molded from the polycarbonate resin composition according to these examples have high integrated transmittance and low yellowness.

  Thus, the polycarbonate resin compositions of Examples 1 to 8 do not impair the heat resistance inherent in the polycarbonate resin (A), have high light transmittance in the visible region, and are stable at high temperatures. Also excellent in properties. And the test piece (vehicle lamp light guide) molded from such a polycarbonate resin composition has small yellowness and excellent hue even when molded at a high molding temperature of 360 ° C.

  On the other hand, the polycarbonate resin composition of Comparative Example 1 was a case where the amount of the specific polyalkylene glycol (B) was small, and the test piece molded at a high temperature had a low integrated transmittance.

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

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

  The polycarbonate resin composition of Comparative Example 5 does not contain the specific polyalkylene glycol (B), and is a test in which the specific phosphite compound (C) and the compound (D) are used in combination and molded at a high temperature. The piece had a low integrated transmittance and a high yellowness.

  As described above, the embodiments have been described as examples of the technology in the present invention. To that end, a detailed explanation was provided.

  Accordingly, the components described in the detailed description include not only components essential for solving the problem but also components not essential for solving the problem in order to illustrate the above technique. obtain. Therefore, it should not be immediately recognized that these non-essential components are essential as the non-essential components are described in the detailed description.

  Moreover, since the above-mentioned embodiment is for demonstrating the technique in this invention, a various change, substitution, addition, abbreviation, etc. can be performed in a claim or its equivalent range.

  The vehicle lamp light guide of the present invention is provided in the vicinity of various vehicle lamps such as vehicle headlamps such as headlamps, auxiliary headlamps such as fog lamps, or daytime running lamps, and has the heat resistance inherent in polycarbonate resin. The properties such as mechanical strength are not impaired, the light transmittance is high, and even when molded at a high temperature, the light transmittance is excellent, and the industrial utility value is extremely high.

Claims (6)

The polyalkylene glycol (B) represented by the following general formula (1) and having a weight average molecular weight of 1000 to 4000 and 0.005 to 3.0 parts by weight and 100 parts by weight of the polycarbonate resin (A) and the following general formula (2 The light guide for vehicle lamps characterized by including the resin composition containing 0.005-1.0 weight part of phosphite compound (C) represented by this.
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):

(In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a represents an integer of 0 to 3) Furthermore, the light guide for vehicle lamps of Claim 1 containing the compound (D) represented by the following general formula (3) or (4).
General formula (3):

(In the formula, 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, or an alkyl group having 6 to 12 carbon atoms. 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 is a single bond, a sulfur atom, or a formula: —CHR; ^7- (wherein 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 a group having 1 to 8 carbon atoms. Or an alkylene group of the formula: * —COR ⁸ — (wherein R ⁸ represents a single bond or an alkylene group having 1 to 8 carbon atoms, and * represents a bond on the oxygen side). Y and Z are either a hydroxyl group or an alcohol having 1 to 8 carbon atoms. A xyl group or an aralkyloxy group having 7 to 12 carbon atoms, the other being a hydrogen atom or an alkyl group having 1 to 8 carbon atoms
General formula (4):

(In formula, R < ⁹ >, R < ¹⁰ > is the C1-C20 alkyl group or the aryl group which may be substituted by the alkyl group, b and c show the integers 0-3.)   The light guide for vehicle lamps 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). The light guide for a vehicle lamp according to claim 2, which is propoxy] dibenzo [d, f] [1,3,2] dioxaphosphine.   The compound (D) represented by the general formula (4) is 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9. The light guide for a vehicle lamp according to claim 2, which is diphosphaspiro [5,5] undecane.   The amount of the phosphite compound (C) is 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A), and the amount of the compound (D) is 0.01. The light guide for a vehicle lamp according to claim 2, wherein the light guide is -0.5 part by weight.