JP5579044B2 - Polycarbonate resin composition and optical molded article comprising the same - Google Patents

Description

  The present invention does not impair heat resistance, mechanical strength, etc., and further, has no white turbidity or a decrease in light transmittance, has a good hue and brightness, and a light guide plate formed by molding the same. The present invention relates to optical molded products such as illuminant materials and nameplates.

  In the liquid crystal display device, a planar light source device is incorporated in order to cope with demands for thinning, lightening, power saving, high luminance and high definition. This planar light source device is provided with a light guide plate having a wedge-shaped cross section having a uniformly inclined surface. In addition, in order to obtain high luminance, a proposal has also been made to provide a light scattering function by forming a prism-shaped uneven pattern on the inclined surface (Patent Document 1).

  The light guide plate is generally obtained by injection molding of a thermoplastic resin, and the concavo-convex pattern is given by transferring the concavo-convex pattern formed on the mold surface. Conventionally, the light guide plate has been formed from a material such as polymethyl methacrylate (PMMA). However, the heat generated inside devices such as personal computers, mobile phones, and PDAs tends to increase, and the thermoplastic resin used has high heat resistance in order to cope with the lighter, thinner and smaller devices, and Resins having high mechanical strength are demanded, and PMMA is being replaced with polycarbonate resins.

  Polycarbonate resin is superior in mechanical properties, thermal properties, and electrical properties to PMMA, but slightly inferior in light transmittance. Therefore, in the case of the planar light source device using the polycarbonate resin light guide plate, there is a problem that the luminance is lowered as compared with PMMA.

  Conventionally, several methods for increasing the luminance of a light guide plate made of polycarbonate resin have been proposed.

  In Patent Document 2, a method of using a fluorescent whitening agent and a bead-shaped cross-linked acrylic resin in combination, improving luminance with a fluorescent whitening agent, and reducing unevenness in luminance with a bead-shaped cross-linked acrylic fine particle, Patent Document 3 discloses an acrylic resin. And a method for improving light transmittance and luminance by adding an alicyclic epoxy resin, and Patent Document 4 proposes a method for improving luminance by introducing copolyestercarbonate to improve the transfer of uneven patterns. Has been.

  However, in the method of Patent Document 2, although the brightness is partially improved, the light transmittance is lowered by the addition of a bead-shaped cross-linked acrylic resin or a fluorescent brightening agent, so that the brightness of a portion far from the light source of the light guide plate is lowered. However, there is a problem that uniform brightness cannot be obtained. In the method of Patent Document 3, the hue is improved by the addition of the acrylic resin, but since it becomes cloudy, the light transmittance and the luminance cannot be increased, and the transmittance is improved by adding the alicyclic epoxy resin. Although there is a possibility, there was a problem that the effect of improving the hue was not recognized. In the case of the method of Patent Document 4, although an improvement effect of fluidity and transferability can be expected, there is a drawback that heat resistance is lowered.

JP-A-10-55712 Japanese Patent Laid-Open No. 9-20860 JP-A-11-158364 JP 2001-215336 A

  The present invention does not impair the original properties of polycarbonate resin, that is, heat resistance, mechanical strength, etc., and further, has no hue and light transmittance reduction, and has good hue and brightness, and molding the same. Optical molded products such as a light guide plate, a surface light emitter material, and a name plate are provided.

  As a result of diligent studies to solve such problems, the present inventor has no deterioration in white turbidity or light transmittance, and good hue and brightness by including polysilane and a phosphorus-based antioxidant in the polycarbonate resin. The present invention was completed by finding that an optical molded product such as a light guide plate can be obtained.

一般式２

（一般式２において、Ｒ１、Ｒ２は炭素数１〜２０のアルキル基、またはアルキル基で置換されてもよいアリール基を、ａ、ｂは整数０〜３を示す。）
That is, the present invention provides a polycarbonate resin (A) 100 parts by weight of polysilane (B) 0.01 to 1 part by weight of a phosphorus antioxidant (C) Ri Do from 0.02 to 2 parts by weight, the polysilane (B ) Is a polysilane represented by the following general formula 1, and the phosphorus-based antioxidant (C) is a compound represented by the following general formula 2 , wherein the resin composition is When the light transmittance was measured using a test piece having a length of 168 mm obtained by injection molding, the integrated light transmittance in a wavelength region of 380 to 780 nm was 30000 or more, and the light transmittance at a wavelength of 400 nm was 40. The present invention relates to a polycarbonate resin composition , and an optical molded article such as a light guide plate comprising the polycarbonate resin composition .
General formula 1

General formula 2

(In General Formula 2, R1 and R2 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a and b represent integers 0 to 3.)

  Since the polycarbonate resin composition of the present invention is excellent in luminance, light transmittance, mechanical properties, heat resistance and hue stability, the hue is also obtained in the molding of a thin (about 0.3 mm thick) light guide plate. It does not change or the resin itself deteriorates, and the industrial utility value is extremely high.

  The polycarbonate resin (A) used in the present invention is 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 of the polymer is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).

  Examples of the dihydroxydiaryl compound include bisphenol 4-, 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 ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone Sulfone, and the like.

  These are used individually or in mixture of 2 or more types. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be mixed and used.

  Furthermore, the above dihydroxyaryl compound and a trivalent or higher phenol compound as shown below may be used in combination.

  Trihydric or higher phenols 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 usually 10,000 to 100,000, preferably 12,000 to 30,000. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as necessary.

Examples of the polysilane (B) used in the present invention include compounds represented by the following general formula 1.
General formula 1

  The compounding quantity of polysilane (B) is 0.01-1 weight part with respect to 100 weight part of polycarbonate resin (A). When the blending amount of the polysilane (B) is less than 0.01 parts by weight, the effect of improving the light transmittance is not sufficient, which is not preferable. Moreover, when a compounding quantity exceeds 1 weight part, since the light transmittance falls and a haze value increases, it is unpreferable.

Examples of the phosphorus antioxidant (C) used in the present invention include compounds represented by the following general formula 2.
General formula 2

（一般式２において、Ｒ１、Ｒ２は炭素数１〜２０のアルキル基、またはアルキル基で置換されてもよいアリール基を、ａ、ｂは整数０〜３を示す。）

(In General Formula 2, R1 and R2 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a and b represent integers 0 to 3.)

  Examples of the compound of the general formula 2 include Adeka Stab PEP-36 manufactured by Adeka Company, which is commercially available.

  The compounding quantity of phosphorus antioxidant (C) is 0.02-2 weight part per 100 weight part of polycarbonate resin (A). If the blending amount is less than 0.02 parts by weight, the thermal stability is poor, which is not preferable. On the other hand, when the amount exceeds 2 parts by weight, the light transmittance is lowered and the haze value is raised, which is not preferable. The amount is preferably 0.04 to 1 part by weight, more preferably 0.05 to 0.2 part by weight. In this range, the light transmittance does not decrease, and excellent thermal stability is exhibited.

  In addition, various heat stabilizers, antioxidants, colorants, mold release agents, softeners, antistatic agents, and other additives, impact modifiers, and other polymers are added as long as the effects of the present invention are not impaired. You may mix | blend.

  There are no particular limitations on the method of mixing the various components of the polycarbonate resin composition of the present invention, and examples thereof include mixing with a known mixer such as a tumbler or ribbon blender or melt kneading with an extruder.

  There is no restriction | limiting in particular in the method to shape | mold the polycarbonate resin composition of this invention, A well-known injection molding method, a compression molding method, etc. can be used.

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

The following were used as raw materials.
Polycarbonate resin (A):
Polycarbonate resin synthesized from bisphenol A and phosgene (Sumitomo Dow Caliber 200-13, hereinafter abbreviated as PC)
Polysilane (B):
Ogsol SI-30-10
(Osaka Gas Chemical Co., Ltd., hereinafter abbreviated as SI)
Phosphorous antioxidant (C):
ADK STAB PEP-36
(Adeka, abbreviated as P-based AO)

  The above-mentioned various raw materials are collectively put into a tumbler at the blending ratio shown in Table 1, and after dry-mixing for 10 minutes, using a twin screw extruder (TEX30α manufactured by Nippon Steel Works) at a melting temperature of 240 ° C. The various pellets of the polycarbonate resin composition were obtained by kneading.

  Various test pieces for evaluation were prepared using the obtained pellets, and were used for evaluation. The results are shown in Table 1. In addition, each evaluation method is as follows.

(Method of creating test piece for measuring accumulated transmittance and light transmittance)
After drying the obtained pellets at 120 ° C. for 4 hours or longer, using an injection molding machine (FANUC S2000i100A) at a molding temperature of 280 ° C. and a mold temperature of 100 ° C., JIS K7139 multipurpose specimen A type (length 168 mm × thickness) 4 mm). The end face was cut, and the cut end face was mirror-finished using a resin plate end face mirror machine PB-500 manufactured by Megaro Technica.

(Evaluation method of integrated transmittance and light transmittance)
The accumulated transmittance and light transmittance were measured using a Hitachi optical spectrophotometer U-4100 with a long optical path measurement accessory, using a 50 W halogen lamp as a light source, and a mask 5.6 mm × 2.8 mm before the light source, and a mask 6 before the sample. It was determined by measuring the spectral transmittance every 1 nm in a state where 0.0 mm × 2.8 mm was used. The cumulative light transmittance in the wavelength range of 380 to 780 nm was 30000 or more, and the light transmittance at a wavelength of 400 nm was 40% or more.

Judgment: Pass (○), Fail (×)

As shown in Examples 1 and 2, the polycarbonate resin composition having the requirements of the present invention showed high light transmittance.
On the other hand, as shown in Comparative Examples 1 to 4, polycarbonate-based resin compositions that do not have the requirements of the present invention did not exhibit high light transmittance.

Claims (3)

Polycarbonate resin (A) 100 parts by weight of polysilane (B) Ri Do from 0.01 to 1 part by weight and a phosphorus-based antioxidant (C) 0.02 to 2 parts by weight, the polysilane (B) is represented by the following general formula 1 is a polycarbonate resin composition in which the phosphorus-based antioxidant (C) is a compound represented by the following general formula 2 and is obtained by injection molding the resin composition When the light transmittance is measured using a test piece having a length of 168 mm, the accumulated light transmittance in the wavelength region of 380 to 780 nm is 30000 or more, and the light transmittance at a wavelength of 400 nm is 40% or more. A polycarbonate resin composition characterized by the above.
General formula 1

General formula 2

(In General Formula 2, R1 and R2 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a and b represent integers 0 to 3.) An optical molded article obtained by molding the polycarbonate resin composition according to claim 1 . A light guide plate formed by molding the polycarbonate resin composition according to claim 1 .