JP6818120B2 - Polycarbonate resin composition for vehicle light guide - Google Patents

Description

The present invention provides a polycarbonate resin composition for a vehicle light guide and a vehicle light, which do not impair the original characteristics of the polycarbonate resin, that is, heat resistance, mechanical strength, etc., do not reduce the light transmittance, and have good hue and brightness. Regarding the guide.

In recent years, for example, in applications such as vehicles and railways such as the Shinkansen, the lamps are lit even during bright hours during the day to inform oncoming vehicles and pedestrians of their existence, and for dressing up. Daylighting is progressing. In particular, in vehicles such as automobiles and motorcycles equipped with daylights in the vicinity of headlamps and rear lamps, such demand has been increasing from an earlier stage than in 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, and for example, those disclosed in Patent Document 1 are known.

Until now, polymethylmethacrylate (hereinafter referred to as PMMA) has been used as the light guide resin, but PMMA is being replaced with polycarbonate resin because of its high heat resistance and high mechanical strength. Has been done.

Polycarbonate resin is superior in mechanical property, thermal property, and electrical property as compared with PMMA, 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, for example, as disclosed in Patent Documents 2 to 6, a resin composition in which a polycarbonate resin and another material are used in combination in order to obtain a light transmittance equal to or higher than that of PMMA and improve the brightness of the light guide. Have been proposed in various ways.

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

Japanese Unexamined Patent Publication No. 2013-234233 Japanese Patent Application Laid-Open No. 09-020860 JP-A-11-158364A Japanese Unexamined Patent Publication No. 2001-215336 Japanese Unexamined Patent Publication No. 2004-051700 International Publication No. 2011/083635

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

As a result of diligent studies to solve the above problems, the present inventors have made the polycarbonate resin contain a specific polyalkylene glycol (B), so that the light transmittance is not lowered and the hue and brightness are good. The present invention has been completed by finding that a light guide for a vehicle lamp 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 the polyalkylene glycol (B) having a weight average molecular weight of 1000 to 4000. To provide a polycarbonate resin composition for a vehicle light guide, which comprises 0.005 to 1.0 part by weight of a phosphite ester compound (C) represented by the following general formula (2). It is a thing.
General formula (1):
HO- (CH ₂ CH ₂ O) m (CH ₂ CH (CH ₃ ) O) n-H (4)
(In the equation, m and n independently indicate an integer of 3 to 60, and m + n indicates 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).

When molded, the polycarbonate resin composition for vehicle light guides in the present invention does not impair the inherent properties of the polycarbonate resin such as heat resistance and mechanical strength, has high light transmittance, and is molded at a high temperature. Even if it is used, it has excellent light transmittance. Therefore, for example, even with a thin light guide having a thickness of about 0.3 mm, the hue changes and the appearance is less likely to deteriorate, and the resin itself is less likely to deteriorate due to high-temperature molding, and its 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 explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of 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 subject matter described in the claims by these.

The vehicle lamp light guide (daytime light guide) of the present invention is provided in the vicinity of vehicle headlights such as headlamps, auxiliary headlights such as fog lamps, and various vehicle lighting fixtures such as daytime running lamps during the daytime. It is used as a lighting tool that is lit by 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 a polycarbonate resin (A) mixed with a specific polyalkylene glycol (B). If necessary, other components may be added to the polycarbonate resin composition used in the present invention.

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

Examples of the dihydroxydiaryl compound include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2-bis (4-hydroxyphenyl) butane, in addition to bisphenol A. 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy) -3-3 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; 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane and the like Bis (hydroxyaryl) cycloalkanes; dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether; dihydroxy such as 4,4'-dihydroxydiphenylsulfide Diarylsulfides; dihydroxydiarylsulfoxides such as 4,4'-dihydroxydiphenylsulfonide, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfoxide; 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy Examples thereof include dihydroxydiaryl sulfones such as -3,3'-dimethyldiphenyl sulfone, which are 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.

Further, the dihydroxydiaryl compound and, for example, the following trivalent or higher valent phenol compound may be mixed and used.

Examples of the trivalent or higher valent phenol compound include fluoroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene, and 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- Examples thereof include bis- [4,4- (4,4'-dihydroxydiphenyl) -cyclohexyl] -propane.

The viscosity average molecular weight of the polycarbonate resin (A) is preferably 1000 to 100,000, more preferably 12,000 to 30,000. When producing such a polycarbonate resin (A), a molecular weight modifier, a catalyst, or the like 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 equation, m and n independently indicate an integer of 3 to 60, and m + n indicates an integer of 8 to 90.)

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

Further, by blending the polyalkylene glycol (B) represented by the general formula (1), it is possible to suppress the generation of shear heat more than necessary when molding the polycarbonate resin composition. Since it is possible to impart mold releasability to the polycarbonate resin composition, it is not necessary to separately add a mold release agent such as a polyorganosiloxane compound.

The weight average molecular weight of the polyalkylene glycol (B) is preferably 1000 to 4000. If the weight average molecular weight of the polyalkylene glycol (B) is less than 1000, the effect of sufficiently improving the light transmittance may not be expected, and conversely, if the weight average molecular weight exceeds 4000, the light transmittance decreases. There is a risk that the clouding rate will increase.

Examples of commercially available polyalkylene glycol (B) include Unilube 50DE-25 (weight average molecular weight 1750) manufactured by Nichiyu Co., Ltd., which is a modified glycol composed of an ethylene glycol unit and a propylene glycol unit. Be 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 0.5 to 1 part by weight with respect to 100 parts by weight of the polycarbonate resin (A). It is preferably 5.5 parts by weight. When the amount of polyalkylene glycol (B) is less than 0.005 parts by weight, the effect of improving the light transmittance and the hue is insufficient, and conversely, when the amount exceeds 3.0 parts by weight, the light transmittance Will decrease and the clouding rate will increase.

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

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 triphenylphosphine, tricresylphosphine, tris (2,4-di-t-butylphenyl) phosphite, trisnonylphenylphosphine and the like. Be done. Among these, tris (2,4-di-t-butylphenyl) phosphite is particularly preferable, and for example, it is commercially available as Irgafos 168 manufactured by BASF (“Irgafos” is a registered trademark of BASF Societyus Europe). It is available at.

The polycarbonate resin composition used in the present invention is a polycarbonate resin (A) mixed with a specific polyalkylene glycol (B) and a specific phosphite ester compound (C). , The compound (D) represented by the general formula (3) or the general formula (4) is preferably contained.
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 each independently have a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, and 6 to 12 carbon atoms. Alkylcycloalkyl group, aralkyl group or phenyl group having 7 to 12 carbon atoms. R ⁴ represents hydrogen atom or alkyl group having 1 to 8 carbon atoms. X is a single bond, sulfur atom or formula: -CHR. ⁷ − (Here, R ⁷ indicates a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms). A indicates a group having 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 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 has a hydrogen atom or 1 to 8 carbon atoms. (Indicating an alkyl group)

In the general formula (3), R ² , R ³ , R ⁵ and R ⁶ are independently hydrogen atoms, alkyl groups having 1 to 8 carbon atoms, cycloalkyl groups having 5 to 8 carbon atoms, and ⁶ carbon atoms, respectively. It shows an alkylcycloalkyl group of ~ 12, an aralkyl group or a phenyl group having 7 to 12 carbon atoms.

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. Examples thereof include a group, a t-pentyl group, an i-octyl group, a t-octyl group, a 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, a cyclooctyl group and the like. Examples of the alkylcycloalkyl group having 6 to 12 carbon atoms include a 1-methylcyclopentyl group, a 1-methylcyclohexyl group, a 1-methyl-4-i-propylcyclohexyl group and the like. Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, an α-methylbenzyl group, an α, α-dimethylbenzyl group and the like.

It is preferable that R ² , R ³ and R ⁵ are independently alkyl groups having 1 to 8 carbon atoms, cycloalkyl groups having 5 to 8 carbon atoms, or alkyl cycloalkyl groups having 6 to 12 carbon atoms, respectively. .. In particular, R ² and R ⁵ are preferably t-alkyl groups such as t-butyl group, t-pentyl group and t-octyl group, cyclohexyl group or 1-methylcyclohexyl group, respectively. In particular, R ³ has the number of carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group and t-pentyl group. It is preferably an alkyl group of 1 to 5, and more preferably a methyl group, a t-butyl group or a t-pentyl group.

The 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 a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group. , N-Butyl group, i-butyl group, sec-butyl group, t-butyl group, t-pentyl group and the like, more preferably an alkyl group having 1 to 5 carbon atoms.

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 above-mentioned explanations of R ² , R ³ , R ⁵ and R ⁶ . 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 the formula: -CHR ⁷ - represents a group represented by. 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 group and the cycloalkyl group exemplified in the explanations of R ² , R ³ , R ⁵ and R ⁶ , respectively. Be 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 present, and more preferably 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 a methylene group, an ethylene group, a propylene group, a butylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, a 2,2-dimethyl-1,3-propylene group and the like. , Which is preferably a propylene group. Further, the formula: * - COR ⁸ - ^{R 8} in the 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 showing R ⁸ include the alkylene group exemplified in the above description of A. R ⁸ is preferably a single bond or an ethylene group. Further, the formula: * ^- COR 8 - * is in a bond of the oxygen side, indicating that a carbonyl group is bonded to an 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 is a hydrogen atom or 1 to 1 carbon atoms. Shows 8 alkyl groups. 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, a pentyloxy group and the like. Examples of the aralkyloxy group having 7 to 12 carbon atoms include a benzyloxy group, an α-methylbenzyloxy group, an α, α-dimethylbenzyloxy group and the like. Examples of the alkyl group having 1 to 8 carbon atoms include the alkyl groups exemplified in the above-mentioned explanations of R ² , R ³ , R ⁵ and R ⁶ .

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] dioxaphosfepine, 6- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propoxy] -2,4,8 , 10-Tetra-t-Butyldibenzo [d, f] [1,3,2] dioxaphosphepine, 6- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propoxy] -4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo [d, g] [1,3,2] dioxaphosphocin, 6- [3- (3,5-di-t) -Butyl-4-hydroxyphenyl) propionyloxy] -4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo [d, g] [1,3,2] dioxaphosphocin and the like. Be done. Among these, when the obtained polycarbonate resin composition is used in a field where optical properties are particularly required, 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4) -Hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1,3,2] dioxaphosfepine is suitable, for example, Sumitomo Chemical Co., Ltd.'s Sumilyzer GP ("Sumilyzer"). 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。）

(In the formula, R ⁹ and R ¹⁰ each independently 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 are independently 0. Indicates an integer of ~ 3.)

As a compound represented by the general formula (4), for example, ADEKA 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 preferably 0.005 to 1.0 parts by weight, preferably 0.01 to 0.5 parts by weight, based on 100 parts by weight of the polycarbonate resin (A). It is more preferable that the amount is 0.02 to 0.1 parts by weight.

When the phosphite ester compound (C) and the compound (D) are used in combination, the amount of the phosphite ester compound (C) is 0.01 to 0 with respect to 100 parts by weight of the polycarbonate resin (A). It is preferably .5 parts by weight and the amount of compound (D) is preferably 0.01 to 0.5 parts by weight. Further, it is preferable that the amount of the phosphite ester compound (C) is 0.02 to 0.05 parts by weight and the amount of the compound (D) is 0.02 to 0.05 parts by weight.

Further, the polycarbonate resin composition used in the present invention includes, for example, a heat stabilizer, an antioxidant, a colorant, a mold release agent, a softener, an antistatic agent, as long as the effects of the present invention are not impaired. Various additives such as an impact improving agent, 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 ester compound (C) and the compound (D), and various additives as required. The type and amount of each component of the polymer other than the polycarbonate resin (A) and the polycarbonate resin (A) 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. There is a way to do it.

The light guide for a vehicle lamp of the present invention is formed by molding the polycarbonate resin composition obtained as described above. The method for manufacturing 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, compression molding method, or the like.

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

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

The following materials were used as raw materials.
1. 1. Polycarbonate resin (A)
Polycarbonate resin Caliber 200-80 synthesized from bisphenol A and carbonyl chloride
(Product name, manufactured by Sumika Stylon Polycarbonate Co., Ltd., "Calibre" is a registered trademark of Stylon Europ Gembeher, viscosity average molecular weight: 15,000, hereinafter referred to as "PC")

2. 2. Polyalkylene glycol (B)
Modified glycol HO- (CH ₂ CH ₂ O) ₁₇ (CH ₂ CH (CH ₃ ) O) _17- H consisting of ethylene glycol unit and propylene glycol unit
Unilube 50DE-25
(Product name, NOF Corporation, weight average molecular weight: 1750, hereinafter referred to as "Compound B")

3. 3. Phosphite ester 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）

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

Examples 1-8 and Comparative Examples 1-3
Each of the above raw materials was put into a tumbler at the blending ratios shown in Tables 1 and 2, and after drying and mixing for 10 minutes, a twin-screw extruder (manufactured by Japan Steel Works, Ltd., TEX30α) was used. Melt kneading was performed at a melting temperature of 220 ° C. to obtain pellets of a polycarbonate resin composition.

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

(Method of preparing test piece)
After drying the obtained pellets at 120 ° C. for 4 hours or more, JIS K 7139 “Plastic-” was used at an injection molding machine (ROBOSHOT S2000i100A manufactured by FANUC Co., Ltd.) at a molding temperature of 360 ° C. and a mold temperature of 80 ° C. A specified multipurpose 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 (Plastic Beauty PB-500, manufactured by Megaro Technica Co., Ltd.).

(Evaluation method of integrated transmittance)
A spectrophotometer (UH4150, manufactured by Hitachi, Ltd.) is equipped with a long-light path measurement accessory, and a 50 W halogen lamp is used as the light source. The light source front mask is 5.6 mm x 2.8 mm, and the sample front mask is 6.0 mm x. Using 2.8 mm, the spectral transmittance of the test piece in the length of 168 mm was measured for each 1 nm in the region of wavelength 380 to 780 nm. The measured spectral transmittances were integrated and the tens digit was rounded off to obtain each integrated transmittance. In addition, the integrated transmittance of 30,000 or more was regarded as good (indicated by ◯ in the table), and less than 30,000 was regarded as defective (indicated by x in the table).

(Evaluation method of yellowness)
Based on the spectral transmittance measured in the method for evaluating the integrated transmittance, the yellowness of each was determined in a 10-degree field of view using a standard light source D65. When the yellowness was 20 or less, it was considered good (indicated by ◯ in the table), and when it exceeded 20, it was considered defective (indicated by x in the table).

The polycarbonate resin compositions of Examples 1 to 8 are composed of a polycarbonate resin (A), a specific polyalkylene glycol (B) represented by the general formula (1), and a specific phosphite ester compound (C). , If necessary, the compound (D) is blended in a specific ratio. The test pieces (light guides for vehicle lamps) molded from the polycarbonate resin composition according to these examples have high integrated transmittance and low yellowness.

As described above, 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 the light transmittance is stable at high temperature. It is also excellent in sex. A test piece (light guide for a vehicle lamp) molded from such a polycarbonate resin composition has a small yellowness and an excellent hue even when molded at a high molding temperature of 360 ° C.

On the other hand, in the polycarbonate resin composition of Comparative Example 1, when the amount of the specific polyalkylene glycol (B) was small, 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 formed at a high temperature has a low integrated transmittance and a large yellowness. It was.

The polycarbonate resin composition of Comparative Example 3 does not contain a specific polyalkylene glycol (B), and is a test in which a specific phosphite ester compound (C) and a compound (D) are used in combination, and is molded at a high temperature. One piece had a low integrated transmittance and a large yellowness.

As described above, an embodiment has been described as an example of the technique in the present invention. To that end, a detailed explanation was provided.

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

Further, since the above-described embodiment is for exemplifying the technique of the present invention, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or the equivalent scope thereof.

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

Claims (6)

Represented by the following general formula (1) with respect to 100 parts by weight of the polycarbonate resin (A), 0.005 to 3.0 parts by weight of the polyalkylene glycol (B) having a weight average molecular weight of 1000 to 4000 and the following general formula ( A polycarbonate resin composition for a vehicle light guide, which contains 0.005 to 1.0 parts by weight of the phosphite ester compound (C) represented by 2) .
General formula (1):
HO- (CH ₂ CH ₂ O) m (CH ₂ CH (CH ₃ ) O) n-H (4)
(In the equation, m and n independently indicate an integer of 3 to 60, and m + n indicates 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 following general formula (3) or the compound represented by (4) a (D), according to claim 1 a vehicle light guide polycarbonate resin composition.
General formula (3):

(In the formula, R ² , R ³ , R ⁵ and R ⁶ each independently have a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, and 6 to 12 carbon atoms. Alkylcycloalkyl group, aralkyl group or phenyl group having 7 to 12 carbon atoms. R ⁴ represents hydrogen atom or alkyl group having 1 to 8 carbon atoms. X is a single bond, sulfur atom or formula: -CHR. ⁷ − (Here, R ⁷ indicates a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms). A indicates a group having 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 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 has a hydrogen atom or 1 to 8 carbon atoms. (Indicating an alkyl group)
General formula (4):

(In the formula, R ⁹ and R ¹⁰ are alkyl groups having 1 to 20 carbon atoms or aryl groups that may be substituted with alkyl groups, and b and c are integers 0 to 3.) Formula (2) phosphorous acid ester compound represented by (C) is tris (2,4-di -t- butyl-phenyl) phosphite, a vehicle light guide polycarbonate resin composition of claim 1, wherein Stuff. The 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 polycarbonate resin composition for a vehicle light guide according to claim 2 , which is propoxy] dibenzo [d, f] [1,3,2] dioxaphosfepine. 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. -The polycarbonate resin composition for a vehicle light guide according to claim 2 , which is a diphosphaspiro [5,5] undecane. The amount of the phosphite ester 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 polycarbonate resin composition for a vehicle light guide according to claim 2 , which is ~ 0.5 parts by weight.