JP6401044B2 - 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 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. A molded light guide for a vehicle lamp is provided.

  As a result of intensive studies to solve such problems, the present inventors have made light transmission by incorporating a specific tetramethylene glycol derivative (B) and a specific phosphite compound into a polycarbonate resin. The present invention was completed by finding that a light guide for a vehicle lamp having a good hue and brightness can be obtained without a decrease in rate.

That is, the present invention includes a polycarbonate resin (A), the result contains tetramethylene glycol derivative represented by the following general formula (1) (B), phosphorous acid ester-based compound and (C), the tetra The methylene glycol derivative (B) has a weight average molecular weight of 1000 to 4000, the phosphite compound (C) is tris (2,4-di-t-butylphenyl) phosphite, and the tetramethylene glycol The amount of the derivative (B) is 0.005 to 5.0 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A), and the amount of the phosphite compound (C) is the polycarbonate resin ( A) To provide a light guide for a vehicle lamp formed by molding a resin composition that is 0.005 to 5.0 parts by weight with respect to 100 parts by weight. .
General formula (1)
HO (C4H8O) m (C3H6O) nH (1)
(In the formula, m and n each independently represent an integer of 4 to 60, and m + n represents an integer of 20 to 90)

  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.

  In addition, 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 subject matter described in the claims.

  The light guide for vehicle lamps (daytime light guide) of the present invention is daytime lighting provided in the vicinity of 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 (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 tetramethylene glycol derivative (B) is represented by the following general formula (1).
_{HO (C 4 H 8 O)} m (C 3 H 6 O) n H (1)
(In the formula, m and n each independently represent an integer of 4 to 60, and m + n represents an integer of 20 to 90)

  Until now, it has been attempted to improve the light transmittance of the polycarbonate resin by adding polyoxyalkylene glycol. However, the polyoxyalkylene glycol has insufficient heat resistance. If the blended polycarbonate resin composition is molded at a high temperature, the brightness and light transmittance of the molded product will decrease. On the other hand, the specific tetramethylene glycol derivative (B) represented by the general formula (1) is a bifunctional random copolymer, has high heat resistance, and is represented by the general formula (1). A molded article obtained by molding a polycarbonate resin composition containing the specific tetramethylene glycol derivative (B) to be molded at a high temperature has high luminance and light transmittance.

  In addition, since the tetramethylene glycol derivative (B) represented by the general formula (1) has appropriate lipophilicity, it is excellent in compatibility with the polycarbonate resin (A). Therefore, the tetramethylene glycol derivative (B) ) Improves the transparency of the molded product obtained from the polycarbonate resin composition.

  Furthermore, by blending the tetramethylene glycol derivative (B) represented by the general formula (1), it is possible to suppress the generation of unnecessarily shearing heat when molding the polycarbonate resin composition. In addition, since release properties can be imparted to the polycarbonate resin composition, for example, a release agent such as a polyorganosiloxane compound may not be added separately.

  In the general formula (1), m and n are each independently an integer of 4 to 60, and m + n is an integer of 20 to 90. Furthermore, m and n are each independently It is preferably an integer of 6 to 40, and m + n is preferably an integer of 20 to 60.

  The tetramethylene glycol derivative (B) has a weight average molecular weight of preferably 1000 to 4000, more preferably 2000 to 3000. When the weight average molecular weight of the tetramethylene glycol derivative (B) is less than 1000, there is a fear that a sufficient improvement effect of the light transmittance may not be expected. Conversely, when the weight average molecular weight exceeds 4000, the light transmittance decreases. As a result, the fogging rate may increase.

  Commercially available tetramethylene glycol derivatives (B) include, for example, polyserine DCB-2000 (weight average molecular weight 2000), polyserine DCB-1000 (weight average molecular weight 1000) manufactured by NOF Corporation (" Polyserine ”is a registered trademark).

  The amount of the tetramethylene glycol derivative (B) is 0.005 to 5.0 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A), 0.1 to 2.0 parts by weight, and further 0.5 to The amount is preferably 1.5 parts by weight. When the amount of the tetramethylene glycol derivative (B) is less than 0.005 parts by weight, the effect of improving the light transmittance and hue is insufficient. On the other hand, when the amount of the tetramethylene glycol derivative (B) exceeds 5.0 parts by weight, the light transmittance is lowered and the clouding rate is increased.

  The polycarbonate resin composition in the present invention contains a phosphite compound (C) together with the specific tetramethylene glycol derivative (B) represented by the general formula (1). Thus, by blending the specific tetramethylene glycol derivative (B) and the phosphite compound (C) at the same time, the properties such as heat resistance and mechanical strength inherent to the polycarbonate resin (A) are impaired. The polycarbonate resin composition with improved light transmittance is obtained.

As the phosphite compound (C), for example, a compound represented by the general formula (2) is particularly suitable. (In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms, 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, Irgafos 168 manufactured by BASF ("Irgafos" is a registered trademark of BASF Societas Europea) is commercially available. Is available.

Examples of the phosphite compound (C) include compounds represented by the following general formula (3) in addition to the compounds represented by the general formula (2).
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, and the other represents 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.

Examples of the phosphite compound (C) include, in addition to the compound represented by the general formula (2) and the compound represented by the general formula (3), for example, represented by the general formula (4). The compound which is made is mentioned.
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 compound (C) is 0.005 to 5.0 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A), and 0.01 to 0.5 parts by weight. 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 light transmittance and hue are not sufficiently improved. Conversely, when the amount of the phosphite compound (C) exceeds 5.0 parts by weight, the effect of improving the light transmittance and hue is insufficient.

  In addition, when using the compound represented by the said General formula (2) as a phosphite ester type compound (C), the quantity is 0.005-1.0 weight with respect to 100 weight part of polycarbonate resin (A). It is preferable that it is a part because the effect of improving light transmittance and hue is greater.

  Moreover, when using the compound represented by the said General formula (3) as a phosphite compound (C), the quantity is 0.05-2.0 weight with respect to 100 weight part of polycarbonate resin (A). It is preferable that it is a part because the effect of improving light transmittance and hue is greater.

  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 tetramethylene glycol derivative (B), the phosphite compound (C), and the various additives and polycarbonate resins as necessary. For polymers other than (A), the type and amount of each component are appropriately adjusted, and these are mixed in a known mixer such as a tumbler or ribbon blender, or melt kneaded in an extruder. Can be 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 producing the optical molded product, and examples thereof include a method of molding a polycarbonate resin composition by a known injection molding method, compression molding method or the like.

  The optical molded product obtained as described above is suitable as, for example, a light guide plate, a surface light emitter material, and a name plate.

  As described above, the second embodiment has been described as an example of the technique disclosed in the present application. However, the technology in 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, “parts” 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. Tetramethylene glycol derivative (B)
Polyoxytetramethylene polyoxypropylene glycol (random type)
Polyserine DCB-2000
(Trade name, manufactured by NOF Corporation, weight average molecular weight: 2000, hereinafter referred to as “compound B”)

3. Phosphite compound (C)
3-1. 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Ｃ１」という）

Irgaphos 168
(Trade name, manufactured by BASF, hereinafter referred to as “Compound C1”)

4). Others 4-1. Polytetramethylene glycol ether / polyoxyethylene glycol random copolymer polyether Polyserine DC-3000E
(Trade name, manufactured by NOF Corporation, weight average molecular weight: 3000, hereinafter referred to as “compound B ′”)

4-2. Polyorganosiloxane compound having phenyl group, methoxy group and vinyl group KR-511
(Product name, manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter referred to as “KR”)

(1) Embodiment Examples 1 to 8 and Comparative Examples 1 to 6
The raw materials are collectively put into a tumbler at the ratio shown in Table 1, and after dry mixing for 10 minutes, using a twin screw extruder (manufactured by Nippon Steel Works, TEX30α), a melting temperature of 220 ° C. And kneaded to obtain pellets of 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 Table 1.

(Test piece preparation method)
(I) Pre-dwelling test piece After the obtained pellets were dried at 120 ° C for 4 hours or more, an injection molding machine (manufactured by FANUC CORPORATION, ROBOSHOT S2000i100A) was used at a molding temperature of 360 ° C and a mold temperature of 80 ° C. , JIS K 7139 “Plastic test piece” was used to prepare a multipurpose test piece A type (total length: 168 mm × thickness: 4 mm). 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).

(II) Test piece after residence After the molten pellet was held at 360 ° C. for 10 minutes in the cylinder of the injection molding machine, a test piece after residence was produced by the same method as the production method of the test piece before residence.

(Evaluation method of integrated transmittance)
A spectrophotometer (manufactured by Hitachi, Ltd., U-4100) 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. In the state where 0 mm × 2.8 mm was used, the spectral transmittance of each of the test piece before staying and the test piece after staying for each 1 nm in the wavelength range of 380 to 780 nm was measured in the full length direction of the test piece. 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. In addition, 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 tetramethylene glycol derivative (B) represented by the general formula (1) and a phosphite compound (C). These are blended at specific ratios. Therefore, not only the test piece before residence molded from the polycarbonate resin composition, that is, the test piece molded without being held in the injection molding machine, but also the test piece after residence, ie, in the cylinder of the injection molding machine. Even if it is the test piece shape | molded after hold | maintaining for 10 minutes at 360 degreeC, integrated transmittance | permeability is high and yellowness is small.

  As described above, the polycarbonate resin compositions of Examples 1 to 8 do not lose the heat resistance inherent in the polycarbonate resin (A), have high light transmittance in the visible region, and are molded at a high temperature. But it has excellent light transmittance. And the molded article which shape | molded such a polycarbonate resin composition is small in yellowness, is excellent in a hue, and is excellent in a hue even when it shape-processes at high temperature.

  In addition, since especially the compound represented by General formula (2) is mix | blended with these polycarbonate resin compositions of Examples 1-8 as a phosphite compound (C), this general formula ( 2) and the specific tetramethylene glycol derivative (B) represented by the general formula (1), due to the synergistic effect, the light transmittance in the visible region, the light transmittance when molded at high temperature , Hue, and the effect of improving hue when molded at a high temperature is greater.

  On the other hand, since the polycarbonate resin composition of Comparative Example 1 has a small amount of the specific tetramethylene glycol derivative (B), both the test piece before residence and the test piece after residence have a low integrated transmittance, and Yellowness is large. Thus, the polycarbonate resin composition of Comparative Example 1 has a low light transmittance in the visible region and a low light transmittance when molded at a high temperature. And the molded product which shape | molded such a polycarbonate resin composition is inferior to the hue at the time of shape | molding at high temperature, and a yellow degree is large and is inferior to a hue.

  Since the polycarbonate resin composition of Comparative Example 2 has a large amount of the specific tetramethylene glycol derivative (B), the accumulated transmittance of the test piece before staying is low. In addition, after the residence, the components were decomposed in the test piece, and it was impossible to measure the spectral transmittance. Thus, the polycarbonate resin composition of Comparative Example 2 is extremely inferior in heat resistance.

  Since the polycarbonate resin composition of Comparative Example 3 has a small amount of the phosphite compound (C), the test piece before residence has a high integrated transmittance and a small yellowness, but the test piece after residence is The integrated transmittance is low and the yellowness is large. Thus, the polycarbonate resin composition of Comparative Example 3 is inferior in heat resistance.

  Since the polycarbonate resin composition of Comparative Example 4 has a large amount of the phosphite compound (C), the accumulated transmittance of the test piece before staying is low and the yellowness is large. In addition, after the residence, the components were decomposed in the test piece, and it was impossible to measure the spectral transmittance. Thus, the polycarbonate resin composition of Comparative Example 4 is extremely inferior in heat resistance.

  The polycarbonate resin composition of Comparative Example 5 is not a specific tetramethylene glycol derivative (B) represented by the general formula (1) but a polytetramethylene glycol ether / polyoxyethylene glycol random copolymer polyether. Therefore, the pre-staying test piece has a high integrated transmittance and a low yellowness, but the post-staying test piece has a low integrated transmittance and a high yellowness. Thus, the polycarbonate resin composition of Comparative Example 5 is inferior in heat resistance.

  The polycarbonate resin composition of Comparative Example 6 is obtained by further blending the polycarbonate resin composition of Comparative Example 5 with a polyorganosiloxane compound, and the pre-dwelling test piece has a high integrated transmittance and a low yellowness. . However, the post-staying test piece has a slightly higher integrated transmittance and lower yellowness than the post-staying test piece of the polycarbonate resin composition of Comparative Example 5, but both are values judged to be good. The difference is big. Thus, the polycarbonate resin composition of Comparative Example 6 is inferior in heat resistance.

  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, replacement, 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 (3)

A polycarbonate resin (A), a tetramethylene glycol derivative (B) represented by the following general formula (1), and a phosphite compound (C) are contained, and the tetramethylene glycol derivative (B) The weight average molecular weight is 1000 to 4000, the phosphite compound (C) is tris (2,4-di-t-butylphenyl) phosphite, and the amount of the tetramethylene glycol derivative (B) Is 0.005 to 5.0 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A), and the amount of the phosphite compound (C) is 100 parts by weight of the polycarbonate resin (A). A light guide for a vehicle lamp formed by molding a resin composition that is 0.005 to 5.0 parts by weight.
General formula (1)
_{HO (C 4 H 8 O)} m (C 3 H 6 O) n H (1)
(In the formula, m and n each independently represent an integer of 4 to 60, and m + n represents 20 to 90.
Indicates an integer) The light guide for vehicle lamps according to claim 1 , wherein the amount of the phosphite compound (C) is 0.005 to 1.0 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A). The amount of the polytetramethylene glycol derivative (B) is 0.1 to 2.0 parts by weight of the polycarbonate resin (A) 100 parts by weight of the amount of the phosphite ester compound (C), polycarbonate The light guide for vehicle lamps of Claim 1 which is 0.01-0.5 weight part with respect to 100 weight part of resin (A).