JP2014051539A - Polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition having excellent surface hardness and excellent color.SOLUTION: A polycarbonate resin composition comprises: 100 pts.wt. of a resin component composed of 35-75 wt.% of a polycarbonate resin (A) and 25-65 wt.% of a surface hardness improver (B); and 0.02-1 pt.wt. of a phosphorus-based antioxidant (C). In the polycarbonate resin composition, the surface hardness improver (B) is a copolymer composed of 5-80 wt.% of an aromatic (meth)acrylate unit and 20-95 wt.% of methyl methacrylate unit and a weight average molecular weight of the copolymer is 5000-30000.

Description

  The present invention relates to a polycarbonate resin composition excellent not only in surface hardness but also in hue.

Polycarbonate resin is a thermoplastic resin excellent in impact resistance, heat resistance, transparency, thermal stability, and the like, and is therefore used as a substitute for glass in windows and display parts of automobiles and building materials. However, the polycarbonate resin has a drawback that it has a low surface hardness and is easily damaged, and its use is limited.
In order to improve this defect, a method of coating an ultraviolet curable resin on a polycarbonate resin surface has been proposed. However, this method has a problem that due to the flexibility derived from the polycarbonate resin, the pencil hardness required for display applications cannot be satisfied.
On the other hand, in order to obtain a molded article excellent in surface hardness and transparency, a resin composition of a polycarbonate resin and an acrylic surface hardness improver has been proposed. However, this resin composition has a problem that the surface hardness is high but the hue is inferior.

JP 2009-280713 A JP 2010-116501 A

  An object of the present invention is to provide a polycarbonate resin composition that solves the above-mentioned problems, that is, has a high surface height and an excellent hue.

  As a result of intensive studies to solve the above problems, the present inventors have found that a polycarbonate resin composition excellent not only in surface hardness but also in hue can be obtained by using a specific antioxidant. The present invention has been completed.

  That is, the present invention relates to phosphorous antioxidant (C) 0.02 to 100 parts by weight of resin component consisting of 35 to 75% by weight of polycarbonate resin (A) and 25 to 65% by weight of surface hardness improver (B). A polycarbonate resin composition containing 1 part by weight, wherein the surface hardness improver (B) is a copolymer comprising 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl methacrylate units, And the weight average molecular weight of the said copolymer is 5000-30000, It is related with the polycarbonate resin composition characterized by the above-mentioned.

The molded product obtained from the polycarbonate resin composition of the present invention has high surface hardness and excellent hue. Therefore, it is suitably used for applications where scratches on the surface of the molded product are avoided and transparency is required, such as displays, electrical / OA equipment, automobile parts, interiors, exteriors, and the like.

  Hereinafter, the present invention will be described in detail.

The polycarbonate resin (A) used in the present invention is a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted or a transesterification method obtained by reacting a dihydroxydiaryl compound and a carbonate 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 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 can 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, 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 25,000 to 39000, and more preferably 28000 to 35,000. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as necessary.

  The surface hardness improver (B) used in the present invention is a copolymer composed of 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl methacrylate units. The weight average molecular weight of the coalescence is 5000-30000. In the present specification, (meth) acrylate means acrylate or methacrylate.

Examples of the aromatic (meth) acrylate include phenyl (meth) acrylate and benzyl (meth) acrylate. These can be used alone or in combination of two or more. Of these, phenyl methacrylate and benzyl methacrylate are preferable, and phenyl methacrylate is more preferable.

If the content of the aromatic (meth) acrylate unit in the surface hardness improver (B) is 5% by weight or more, transparency is maintained, and if it is 80% by weight or less, the phase with the polycarbonate resin (A) is maintained. Since the capacity is not too high and the transferability to the surface of the molded body is not lowered, the surface hardness is not lowered, which is preferable. Moreover, if the content rate of an aromatic (meth) acrylate unit is the range of 20 to 70 weight%, it is still more preferable from expressing high surface hardness, maintaining transparency further.

  The surface hardness improver (B) may contain other monomer units other than the aromatic (meth) acrylate unit and the methyl methacrylate unit, if necessary. Examples of other monomers constituting other monomer units include methacrylates such as ethyl methacrylate, butyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate; methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, 2- Acrylates such as ethylhexyl acrylate and glycidyl acrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; diene monomers such as butadiene, isoprene and dimethylbutadiene; vinyl ether ethers such as vinyl methyl ether and vinyl ethyl ether Body; carboxylic acid vinyl monomers such as vinyl acetate and vinyl butyrate; olefin monomers such as ethylene, propylene and isobutylene; acrylic acid, methacrylic acid and male Ethylenically unsaturated carboxylic acid monomers such as acid and itaconic acid; vinyl halide monomers such as vinyl chloride and vinylidene chloride; maleimides such as maleimide, N-phenylmaleimide, N-cyclohexylmaleimide and N-methylmaleimide Monomers; Examples include cross-linking agents such as allyl (meth) acrylate, divinylbenzene, and 1,3-butylene dimethacrylate. Of these, methacrylate, acrylate, and vinyl cyanide monomer are preferable, and acrylate is more preferable from the viewpoint of suppressing thermal decomposition of the surface hardness improver (B). These monomers can be used alone or in combination of two or more.

  When other monomer units are contained, the constituent monomers of the surface hardness improver (B) are aromatic (meth) acrylate units of 5-79.9% by weight, methyl methacrylate units of 20-94.9% by weight. And other monomer units in the range of 0.1 to 10% by weight.

  As a polymerization method of the monomer for obtaining the surface hardness improver (B), a known method such as an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, a bulk polymerization method, or the like can be used. A suspension polymerization method and a bulk polymerization method are preferable, and a suspension polymerization method is more preferable. Further, additives necessary for the polymerization can be appropriately added as necessary, and examples thereof include a polymerization initiator, an emulsifier, a dispersant, and a chain transfer agent.

The weight average molecular weight of the surface hardness improver (B) is 5,000 to 30,000. When the weight average molecular weight is in the range of 5000 to 30000, the compatibility with the polycarbonate resin (A) is good, and the effect of improving the surface hardness is excellent. In addition, Preferably it is the range of 10,000-25000.

The weight average molecular weight is measured using gel permeation chromatography (GPC), and the detailed conditions are as follows:
As a GPC column, PLGEL 5 μm MIXED-C manufactured by Agilent Technologies was used, and THF was used as a mobile phase.

As the phosphorus-based antioxidant (C) used in the present invention, known phosphorus-based antioxidants used for polycarbonate resins, for example, IRGAFOSP-EPQ manufactured by BASF, IRGAFOSP-168 manufactured by BASF, and ADEKA Examples include ADK STAB PEP-36 manufactured by KK Of these, the compound represented by the following general formula 1 can be particularly preferably used.
General formula 1

In General Formula 1, 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.

  The compounding quantity of phosphorus antioxidant (C) is 0.02-1 per 100 weight part of resin components which consist of polycarbonate resin (A) 35-75 weight% and surface hardness improver (B) 25-65 weight%. Parts by weight. When the blending amount is less than 0.02 parts by weight, the hue is inferior, and when it exceeds 1 part by weight, the haze value increases, which is not preferable. Preferably, it is 0.03-0.5 weight part, More preferably, it is the range of 0.04-0.3 weight part.

  Furthermore, various resins, fluorescent brighteners, pigments, dyes, carbon black, fillers, mold release agents, antistatic agents, rubber, softening are added to the polycarbonate resin composition of the present invention as long as the effects of the present invention are not impaired. Materials, spreading agents (liquid paraffin, epoxidized soybean oil, etc.), flame retardants, additives such as organic metal salts, polytetrafluoroethylene resin for preventing dripping, etc. may be blended.

  Examples of the various resins include polystyrene, high impact polystyrene, ABS, AES, AAS, AS, acrylic resin, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polysulfone, and polyphenylene sulfide resin. Or you may use together by 2 or more types.

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

Details of the raw materials used are as follows.
Polycarbonate resin (A):
Polycarbonate resin synthesized from bisphenol A and phosgene (Caliver 200-3, Sumika Stylon Polycarbonate Co., Ltd., viscosity average molecular weight 28,500, hereinafter abbreviated as “PC”)
Surface hardness improver (B):
Copolymer of aromatic (meth) acrylate unit and methyl methacrylate unit (Metbrene H-880 manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight 10,000,
Hereinafter abbreviated as “component B”)
Phosphorous antioxidant (C):
3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane (ADEKA STAB PEP- manufactured by ADEKA) 36, hereinafter abbreviated as “AO”)

  In the blending ratios shown in Tables 1 and 2, each of the above raw materials was put into a tumbler and dry mixed for 4 minutes, and then a twin screw extruder (L / D = 42, Φ = 37 mm, KTX-37 manufactured by Kobe Steel) ) Was melt kneaded at a melting temperature of 240 ° C. to obtain pellets of various polycarbonate resin compositions.

  The obtained pellets were dried at 100 ° C. for 6 hours, and then a test piece (50 mm × 5 mm) for various evaluation items using an injection molding machine (J100S EIIP) manufactured by Nippon Seiko Co., Ltd. under a cylinder temperature of 260 ° C. 90 mm × 3 mm and 50 mm × 90 mm × 2 mm).

The evaluation method is as follows.
(Hue)
The hue of the obtained test piece was a yellowness index (measured with a spectrophotometer (CMS35-SP, manufactured by Murakami Color Research Laboratory) using a 3 mm thick test piece under the conditions of a D65 light source and a viewing angle of 10 °. YI).
YI of 2.0 or less was considered good. The results are shown in Tables 1 and 2.

(Pencil hardness)
Using a test piece having a thickness of 2 mm, in accordance with JISK5600-5-4, a pencil hardness measuring machine (a pencil scratch coating film hardness tester manufactured by Toyo Seiki Co., Ltd.) is used to determine the pencil hardness at which no scratches are observed on the test piece surface. It was. A pencil hardness of HB or higher was considered good. The results are shown in Tables 1 and 2.

(Haze value)
Using a test piece having a thickness of 2 mm, the haze value (H) was determined with a haze meter (HM150, manufactured by Murakami Color Research Laboratory Co., Ltd.) according to JISK7105. The haze value (H) was calculated according to the following formula.
Haze value H (%) = (diffuse transmittance Td / total light transmittance Tt) × 100
A haze value (H) of 2.0% or less was considered good. The results are shown in Tables 1 and 2.

判定： ○： 良好 ×：不良

Judgment: ○: Good ×: Bad

判定： ○： 良好 ×：不良

Judgment: ○: Good ×: Bad

As shown in Examples 1 to 6, those satisfying the constituent requirements of the present invention satisfied the required performance.
On the other hand, as shown in Comparative Examples 1 to 4, those that do not satisfy the constituent requirements of the present invention have the following drawbacks.
In Comparative Example 1, YI was poor when the blending amount of AO was less than the specified amount.
In Comparative Example 2, the amount of AO was greater than the specified amount, and the haze value was poor.
In Comparative Example 3, when the blending amount of the component B (surface hardness improver) was less than the specified amount, the pencil hardness was poor.
Comparative Example 4 was a case where the blending amount of the component B (surface hardness improver) was larger than the prescribed amount, and the haze value became 2.0 or more, resulting in failure.

Claims (4)

Polycarbonate containing 0.02 to 1 part by weight of a phosphorous antioxidant (C) per 100 parts by weight of a resin component comprising 35 to 75% by weight of a polycarbonate resin (A) and 25 to 65% by weight of a surface hardness improver (B) A resin composition, wherein the surface hardness improver (B) is a copolymer comprising 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl methacrylate units, and A polycarbonate resin composition having a weight average molecular weight of 5,000 to 30,000.   The polycarbonate resin composition according to claim 1, wherein the resin component comprises 45 to 65% by weight of a polycarbonate resin (A) and 35 to 55% by weight of a surface hardness improver (B). The polycarbonate resin composition according to claim 1 or 2, wherein the phosphorus-based antioxidant (C) is a compound represented by the following general formula 1.
General formula 1

(In General Formula 1, 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.) The polycarbonate resin composition according to claim 1 or 2, wherein the amount of the phosphorus-based antioxidant (C) is 0.04 to 0.3 parts by weight per 100 parts by weight of the resin component. object.