JP2014062148A - Polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition which contains 0.02 to 1 pts.wt. of a phosphorus-based antioxidant (C) and 0.05 to 3 pts.wt. of a specific ultraviolet absorber (D) per 100 pts.wt. of a resin component composed of 35 to 75 wt.% of a polycarbonate resin (A), 25 to 65 wt.% of a surface hardness improver (B), in which the surface hardness improver (B) is a copolymer composed of 5 to 80 wt.% of an aromatic (meth)acrylate unit and 20 to 95 wt.% of a methyl methacrylate unit and the copolymer has a weight average molecular weight of 5000 and 30000.SOLUTION: A molded product obtained from the polycarbonate resin composition has a high surface hardness and is excellent in hue and weather resistance. Therefore, the molded product can be suitably used for applications in which scratches on the surface of the molded product are avoided, transparency is required and outdoor use is assumed, for example, for a smart phone and a tablet terminal.

Description

  The present invention relates to a polycarbonate resin composition that is excellent not only in surface hardness but also in hue, and also has weather resistance.

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. (See Patent Document 1 and Patent Document 2) However, this resin composition has a problem that the surface hardness is high but the hue and weather resistance are 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-described problems, that is, has a high surface height, excellent hue, and weather resistance.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a specific antioxidant and ultraviolet absorber, so that the polycarbonate resin composition is excellent not only in surface hardness but also in hue and weather resistance. The present inventors have found that a product can be obtained, and have completed the present invention.

  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 comprising 1 part by weight and 0.05 to 3 parts by weight of one or more ultraviolet absorbers (D) selected from benzotriazole-based, triazine-based and oxalic anilide-based ultraviolet absorbers. 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 copolymer has a weight average molecular weight of 5000. It provides a polycarbonate resin composition characterized by being ˜30000.

  The molded product obtained from the polycarbonate resin composition of the present invention has a high surface hardness and is excellent in hue and weather resistance. Therefore, it can be suitably used for applications in which scratches on the surface of the molded product are avoided and transparency is required, and applications where outdoor use is also assumed, such as smartphones and tablet terminals.

  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 Monomer; Cross-linking agents such as aryl (meth) acrylate, divinylbenzene, 1,3-butylene dimethacrylate and the like can be mentioned. 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.

  The ultraviolet absorber (D) used in the present invention is one or more ultraviolet absorbers selected from benzotriazole-based, triazine-based and oxalic anilide-based ultraviolet absorbers. Examples of commercially available products include Tinuvin 329 manufactured by BASF, Seasorb 709 manufactured by Sipro Kasei Co., and Chemisorb 79 manufactured by Chemipro Kasei. Among these, Sanduvor VSU manufactured by Clariant Japan Co. shown in the following formula can be used preferably.

  The compounding amount of the ultraviolet absorber (D) is 0.05 to 3 parts by weight per 100 parts by weight of the resin component consisting of 35 to 75% by weight of the polycarbonate resin (A) and 25 to 65% by weight of the surface hardness improver (B). It is. When the blending amount is less than 0.05 parts by weight, the weather resistance is inferior, and when it exceeds 3 parts by weight, the polycarbonate resin (A) is decomposed and the molecular weight is lowered, which is not preferable. More preferably, it is 0.07-2 weight part, More preferably, it is the range of 0.1-1 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, polyphenylene sulfide resin, and the like. 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”)
UV absorber (D):
Oxalic acid anilide-based UV absorber (Clariant Japan's Sanduvor VSU,
(Hereinafter abbreviated as “UVA”)

  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 × 2 mm).

The evaluation method is as follows.
(Initial hue)
The hue of the obtained test piece was a yellowness index (2 mm thick test piece) measured with a spectrophotometer (CMS35-SP manufactured by Murakami Color Research Laboratory) under the conditions of a D65 light source and a viewing angle of 10 °. YI).
A YI of 3.0 or less was considered good. The results are shown in Tables 1 and 2.

(Weatherability)
A test piece having a thickness of 2 mm was placed in an accelerated weathering tester Sunshine Super Long Life Weather Meter (WELSUNHCH-B type manufactured by Suga Test Instruments Co., Ltd.) and irradiated for 300 hours. Then, YI of the test piece after irradiation was measured according to the initial hue conditions.
A difference (ΔYI) between YI after irradiation and initial YI before irradiation was obtained.
A case where the value of ΔYI was less than 10 was judged as good (◯), and a case where it was 10 or more was judged as bad. 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.

(Molecular weight reduction)
With respect to each of the obtained pellets, the melt borate rate (MVR) was measured under the condition of 280 ° C. under a load of 1.2 kg according to ISO 1133 using a semi-auto melt indexer 2A manufactured by Toyo Seiki. The MVR of PC used as a raw material was also measured under the above conditions, and the difference (ΔMVR) from the MVR value for each of the obtained pellets was calculated.
Those having a value of ΔMVR of less than 27 were evaluated as good (◯), and those having a value of 27 or more were determined as defective. 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 3.0% or less was considered good.

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 6, those not satisfying the constituent requirements of the present invention had the following defects.
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.
In Comparative Example 4, the amount of component B (surface hardness improver) was greater than the specified amount, and the haze value was poor.
In Comparative Example 5, ΔYI was poor when the blended amount of UVA was less than the specified amount.
In Comparative Example 6, when the blending amount of UVA was larger than the specified amount, YI and ΔMVR were poor.

Claims (6)

  Phosphorous antioxidant (C) 0.02 to 1 part by weight and benzotriazole per 100 parts by weight of resin component consisting of polycarbonate resin (A) 35 to 75% by weight and surface hardness improver (B) 25 to 65% by weight A polycarbonate resin composition containing 0.05 to 3 parts by weight of one or more ultraviolet absorbers (D) selected from a series, triazine-based, and oxalic anilide-based ultraviolet absorber, (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 copolymer is 5,000 to 30,000. A polycarbonate resin composition characterized by the above.   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. The polycarbonate resin composition according to claim 1, wherein the ultraviolet absorber (D) is an oxalic anilide-based ultraviolet absorber represented by the following formula.

  2. The polycarbonate resin composition according to claim 1, wherein the blending amount of the ultraviolet absorber (D) is 0.1 to 1 part by weight per 100 parts by weight of the resin component.