TWI486389B - Polycarbonate resin composition and use thereof - Google Patents

Description

Polycarbonate resin composition and use thereof

The present invention relates to a polycarbonate resin composition which does not impair heat resistance, mechanical strength, etc., and which does not cause white turbidity and light transmittance reduction, and has good hue and brightness, and a light guide plate and a surface illuminant material obtained therefrom. Optical molded products such as nameplates.

In the liquid crystal display device, a planar light source device is incorporated in order to meet the requirements of thinness, weight reduction, power saving, high brightness, and high definition. In the planar light source device, a light guide plate having a wedge-shaped cross section having an inclined surface having the same inclination is provided on one surface. Further, it has been proposed to form a concavo-convex pattern having a meandering shape on the inclined surface in order to obtain high lightness to impart a light scattering effect (Patent Document 1).

The light guide plate can usually be obtained by injection molding of a thermoplastic resin, and the uneven pattern can be imparted by transfer of a concave-convex pattern formed on the surface of the mold. Conventionally, the light guide plate has been formed of a material such as polymethyl methacrylate (PMMA). However, there is a tendency for the heat generation in the inside of the personal computer, the mobile phone, the PDA, etc., and in order to cope with the lightness and thinness of the machine, the thermoplastic resin to be used must require a resin having high heat resistance and high mechanical strength. Therefore, PMMA is gradually being replaced by polycarbonate resin.

The polycarbonate resin is superior in mechanical properties, thermal properties, and electrical properties to PMMA, but is slightly inferior in light transmittance. Therefore, in the case of using the planar light source device of the light guide plate made of polycarbonate resin, there is a problem that the brightness is lower than that of PMMA.

In the past, several methods have been proposed for increasing the brightness of a polycarbonate resin light guide plate.

Patent Document 2 has proposed a method of reducing brightness unevenness by using a fluorescent whitening agent and a beaded crosslinked acrylic resin to increase brightness by a fluorescent whitening agent, and reducing uneven brightness by a beaded crosslinked acrylic resin; 3. A method for improving light transmittance and brightness by adding an acrylic resin and an alicyclic epoxy resin has been proposed. In Patent Document 4, it has been proposed to introduce a copolyestercarbonate to impart transfer property to a concave-convex pattern. Improve the method by which to increase the brightness.

However, in the method of Patent Document 2, although the brightness can be partially improved, the addition of the bead-like crosslinked propylene resin and the fluorescent whitening agent lowers the light transmittance, so that it is far from the light source of the light guide plate. The brightness of the part is greatly reduced, and there is a problem that uniform brightness cannot be obtained. In the method of Patent Document 3, although the hue is improved by the addition of the acrylic resin, the white turbidity is caused, so that the light transmittance and the brightness cannot be improved, and the penetration rate may be improved by adding the alicyclic epoxy resin. However, there is a problem that the effect of the hue improvement cannot be seen. In the case of the method of Patent Document 4, the effect of improving fluidity and transferability can be expected, and the heat resistance is lowered.

Patent Document 1: Japanese Patent Laid-Open No. Hei 10-55712

Patent Document 2: Japanese Patent Laid-Open No. 9-20860

Patent Document 3: Japanese Patent Laid-Open No. Hei 11-158364

Patent Document 4: Japanese Patent Laid-Open Publication No. 2001-215336

The present invention provides a polycarbonate resin composition which does not impair the original characteristics (i.e., heat resistance, mechanical strength, etc.) of the polycarbonate resin, and which does not cause white turbidity and light transmittance reduction, and has good hue and brightness. And an optical molded article such as a light guide plate, a surface light-emitting material, or a name plate obtained by molding the same.

The present inventors have deliberately studied to solve the above problems, and as a result, it has been found that by containing a polystyrene resin and a specific antioxidant in a polycarbonate resin, it is possible to obtain no white turbidity and a decrease in light transmittance, hue and brightness. The optical molded article such as a good light guide plate is used to complete the present invention.

That is, the present invention relates to a polycarbonate resin composition characterized by comprising a polystyrene resin (B) of 0.05 to 99.95% by weight of a polycarbonate resin (A) and a weight average molecular weight of 1,000 to 18,000. 3% by weight to 100 parts by weight of the resin component, 0.02 to 2 parts by weight of the phosphorus-based antioxidant (C) and/or the phenol-based antioxidant (D); and an optical molded article such as a light guide plate obtained therefrom .

Since the polycarbonate resin of the present invention is excellent in brightness, light transmittance, mechanical properties, heat resistance, and hue stability, color change does not occur even in a thin (about 0.3 mm thick) light guide plate. Or the deterioration of the resin itself, the industrial use value is extremely high.

The polycarbonate resin (A) used in the present invention is a phosgene method in which various dihydroxydiaryl compounds are reacted with phosgene, or a dihydroxydiaryl compound and diphenyl carbonate. A polymer obtained by a transesterification method of a carbonate reaction is exemplified by a polycarbonate resin produced from 2,2-bis-(4-hydroxyphenyl)propane (bisphenol A).

As the above dihydroxydiaryl compound, in addition to bisphenol A, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-double may be mentioned. (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 a bis(hydroxyaryl)alkane such as bis(4-hydroxy-3,5-dibromophenyl)propane or 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane; , bis(hydroxyaryl)cycloalkanes such as 1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane; 4,4'-dihydroxy a dihydroxydiaryl ether such as phenyl ether or 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether; or a dihydroxy group such as 4,4'-dihydroxydiphenyl sulfide Diaryl sulfoxides; dihydroxydiaryl fluorenes such as 4,4'-dihydroxydiphenylarylene, 4,4'-dihydroxy-3,3'-dimethyldiphenylarylene a dihydroxydiaryl fluorene such as 4,4'-dihydroxydiphenyl fluorene or 4,4'-dihydroxy-3,3'-dimethyldiphenyl hydrazine.

These may be used singly or in combination of two or more. In addition to these, piperazine, dipiperazinehydroquinone, resorcinol, 4,4'-dihydroxybiphenyl or the like may be used.

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

Examples of the trivalent or higher phenol include phloroglucin, 4,6-dimethyl-2,4,6-tris-(4-hydroxyphenyl)-heptene, and 2,4-. Dimethyl-2,4,6-tris(4-hydroxyphenyl)-heptane, 1,3,5-tris(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4- Hydroxyphenyl)-ethane and 2,2-bis-[4,4-(4,4'-dihydroxydiphenyl)cyclohexyl]propane.

The viscosity average molecular weight of the polycarbonate resin (A) is usually 10,000 to 100,000, preferably 12,000 to 25,000, more preferably 12,000 to 18,000. When manufacturing this polycarbonate resin, a molecular weight modifier, a catalyst, etc. may be used as needed.

The polystyrene resin (B) used in the present invention has a weight average molecular weight of 1,000 to 18,000. If the weight average molecular weight of the polystyrene resin (B) is less than 1,000, the light transmittance will be deteriorated, and in the case of more than 18,000, the light transmittance and the atomization rate will be deteriorated, which is not preferable. It is preferably in the range of 1500 to 10,000, more preferably 2000 to 4000.

The composition ratio of the polystyrene resin (B) is preferably 0.05 to 3% by weight based on the resin component composed of (A) and (B), and preferably 0.1 to 1% by weight. When the composition ratio of the polystyrene resin (B) is less than 0.05% by weight, improvement in light transmittance and brightness cannot be expected. Further, when the composition ratio exceeds 3% by weight, the light transmittance is lowered and the haze value is increased, which is not preferable.

As a commercially available polystyrene resin (B), JONCRYL ADF-1300 by BASF Corporation is mentioned.

The phosphorus-based antioxidant (C) and/or the phenol-based antioxidant (D) used in the present invention include the following compounds.

The phosphorus-based antioxidant (C) may be one or more of the compounds represented by the following formulas 1, 2 and 3.

Formula 1

(In the formula 1, R ¹ to R ⁴ represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.)

Formula 2

(In the formula 2, R ⁵ and R ^{6 each} 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.)

Formula 3

(In the formula 3, R ⁷ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and c represents an integer of 0 to 3.)

The compound of the formula 1 is Sandostab P-EPQ manufactured by Clariant Japan Co., Ltd., and the compound of the formula 2 is ADK STAB PEP-36 manufactured by Adeka Co., Ltd., and the compound of the formula 3 is Sumitomo. Sumilizer P-168, a chemical company, is commercially available.

Further, examples of the phenol-based antioxidant (D) include compounds of the following formula 4.

Formula 4

(In the formula 4, R ⁸ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group.)

As a compound of the formula 4, commercially available is Irganox 1076 manufactured by Ciba Specialty Chemicals.

The blending amount of the phosphorus-based antioxidant (C) and/or the phenol-based antioxidant (D) is 0.02 to 2 parts by weight based on 100 parts by weight of the resin component composed of (A) and (B). If the amount is less than 0.02 parts by weight, it is not preferable because of poor thermal stability. On the other hand, when it exceeds 2 parts by weight, the light transmittance is lowered and the haze value is increased, which is not preferable. The blending amount is suitably 0.04 to 1 part by weight, more preferably 0.05 to 0.2 part by weight. In this range, the light transmittance is not lowered and excellent thermal stability can be exhibited.

Further, additives such as various heat stabilizers, antioxidants, colorants, mold release agents, softeners, and antistatic agents, impact modifiers, and other polymers may be contained within the range not impairing the effects of the present invention.

The mixing method of the various compounding components of the polycarbonate resin composition of the present invention is not particularly limited, and it may be a mixture of a known mixer, for example, a rotary drum or a spiral belt blender, or an extruder. Melt and knead.

The molding method of the polycarbonate resin composition of the present invention is not particularly limited, and a known injection molding method, compression molding method, or the like can be used.

Hereinafter, the present invention will be specifically described by way of examples, but the invention is not limited thereto. In addition, "parts" and "%" are based on weight.

(Example)

According to the components and the blending amounts of Tables 1 to 4, each of the blending components was mixed with a rotary drum, and melt-kneaded at a cylinder temperature of 220 ° C using a 40-mm diameter single-axis extruder (manufactured by Tanabe Plastic Co., Ltd.) to obtain various particulate matter. .

The combinations used are as follows:

1. Polycarbonate resin:

Polycarbonate resin synthesized from bisphenol A and carbonyl chloride

SD1080 manufactured by Sumitomo Dow Co., Ltd. (viscosity average molecular weight: 15000)

(The following is abbreviated as "PC1".)

Polycarbonate resin synthesized from bisphenol A and carbonyl chloride

SD2000W made by Sumitomo Dow (viscosity average molecular weight: 13,000)

(The following is abbreviated as "PC2".)

2. Polystyrene resin:

JAFCRYL ADF-1300 manufactured by BASF

(weight average molecular weight: 2800, the following is abbreviated as "PS1".)

Polystyrene produced by Aldrich (weight average molecular weight: 800)

(The following is abbreviated as "PS2".)

Polystyrene produced by Aldrich (weight average molecular weight: 4000)

(The following is abbreviated as "PS3".)

Polystyrene produced by Aldrich (weight average molecular weight: 13,000)

(The following is abbreviated as "PS4".)

Polystyrene produced by Aldrich (weight average molecular weight: 20000)

(The following is abbreviated as "PS5".)

Polystyrene produced by Aldrich (weight average molecular weight: 23,000)

(The following is abbreviated as "PS6".)

Polystyrene produced by Aldrich (weight average molecular weight: 35000)

(The following is abbreviated as "PS7".)

3. Phosphorus antioxidants:

P-EPQ made by Clariant Japan

(The following is abbreviated as "P system A01".)

Adeka company ADK STAB PEP-36

(The following is abbreviated as "P system A02".)

Sumitomo Chemical Co., Ltd. P-168

(The following is abbreviated as "P system AO3".)

4. Phenol antioxidants:

Steaming Bart Chemical Company Irganox 1076

(The following is abbreviated as "Ph AO".)

(Method for producing chromaticity, light transmittance, and test piece for measuring haze value)

After the obtained pellets were dried at 120 ° C for 4 hours, an injection molding machine was used.

(J-100SAII, manufactured by Nippon Steel Co., Ltd.) A test piece (90 × 50 × 2 mm) for measuring chromaticity, transmittance, and haze value was prepared at 280 ° C and an injection pressure of 1200 kg/cm ² . (Method of evaluating chromaticity)

The chromaticity was measured using a Spectrophotometer CMS35-SP manufactured by Murakami Color Research Laboratory under a D65 light source and a viewing angle of 10°. The chromaticity measurement is such that the difference between the maximum value and the minimum value of the x and y values when n=10 is 0.0005 or less is acceptable. The results are shown in Tables 1 to 4.

(Method for evaluating light transmittance and fog value)

The light transmittance and the haze value were measured by a Haze Meter HM-150 manufactured by Murakami Color Research Laboratory. The total light transmittance Tt was 90.4% or more and the haze value H was 0.7% or less as a pass. The results are shown in Tables 1 to 4. Further, the haze value is defined by the following formula based on the total light transmittance Tt and the diffusion transmittance Td.

Fog value H (%) = (diffusion transmittance Td / total light transmittance Tt) × 100

As shown in Examples 1 to 10, the polycarbonate resin composition having the requirements of the present invention exhibits high light transmittance and brightness, excellent hue stability, and low haze value.

In Comparative Example 1, the amount of PS1 was less than the predetermined amount, and the light transmittance was poor.

In Comparative Example 2, when the amount of PS1 was larger than the prescribed amount, the light transmittance and the fog value were both poor.

In Comparative Example 3, when the amount of the phosphorus-based antioxidant was less than the predetermined amount, the hue stability was poor.

In Comparative Example 4, when the amount of the phosphorus-based antioxidant was more than the prescribed amount, the light transmittance and the fog value were inferior.

In Comparative Example 5, when the amount of the phenol-based antioxidant was less than the predetermined amount, the hue stability was poor.

As shown in Examples 11 and 12, the polycarbonate resin composition having the requirements of the present invention exhibits high light transmittance and brightness, excellent hue and low haze value.

Comparative Example 6 is a case where PS2 having a weight average molecular weight of 800 was used, and the light transmittance was poor.

Comparative Example 7 is a case where PS5 having a weight average molecular weight of 20,000 was used, and the light transmittance was poor.

In Comparative Example 8, in the case of using PS6 having a weight average molecular weight of 23,000, the light transmittance and the haze value were both inferior.

In Comparative Example 9, in the case of using PS7 having a weight average molecular weight of 35,000, the light transmittance and the haze value were both inferior.

Claims (10)

A polycarbonate resin composition comprising 0.05 to 99.95% by weight of a polycarbonate resin (A) and 0.05 to 1% by weight of a polystyrene resin (B) having a weight average molecular weight of 1,000 to 18,000. 100 parts by weight of the resin component, 0.02 to 2 parts by weight of the phosphorus-based antioxidant (C) and/or the phenol-based antioxidant (D). The polycarbonate resin composition of claim 1, wherein the polycarbonate resin (A) has a weight average molecular weight of from 12,000 to 18,000. The polycarbonate resin composition according to claim 1, wherein the polystyrene resin (B) has a weight average molecular weight of 1,500 to 10,000. The polycarbonate resin composition of claim 1, wherein the polystyrene resin (B) has a weight average molecular weight of from 2,000 to 4,000. The polycarbonate resin composition according to any one of claims 1 to 4, wherein the composition ratio of the polystyrene resin (B) is 0.1 to 1% by weight based on the resin component. The polycarbonate resin composition of the first aspect of the invention, wherein the phosphorus-based antioxidant (C) and/or the phenol-based antioxidant (D) is added in an amount of 0.05 based on 100 parts by weight of the resin component. ~0.2 parts by weight. The polycarbonate resin composition of the first aspect of the invention, wherein the phosphorus-based antioxidant (C) is one or more compounds selected from the group consisting of the compounds represented by the following formulas 1, 2 and 3; (In the formula 1, R ¹ to R ⁴ represent an alkyl group having 1 to 20 carbon atoms or an aryl group substituted by an alkyl group;) (In the formula 2, R ⁵ and R ⁶ represent an alkyl group having 1 to 20 carbon atoms or an aryl group substituted with an alkyl group, and a and b represent integers 0 to 3;) (In the formula 3, R ⁷ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and c represents an integer of 0 to 3). The polycarbonate resin composition of the first aspect of the invention, wherein the phenolic antioxidant (D) is a compound represented by the following formula 4; (In the formula 4, R ⁸ represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group). A molded article for optics obtained by molding the polycarbonate resin composition according to any one of claims 1 to 8. A light guide plate obtained by molding a polycarbonate resin composition according to any one of claims 1 to 8.