JP2016003334A - Polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition which is substantially improved in not only surface hardness but rigidity and warping while retaining original excellent transparency of polycarbonate resins, is usable in, for example, covers of display parts of electrical and electronic apparatuses and replacements for plate glass used in automobiles and construction materials and allows weight saving of products.SOLUTION: A polycarbonate resin composition contains 5-20 pts. wt. of glass flakes (C) in 100 pts. wt. of a resin ingredient comprising 35-58 wt.% of a polycarbonate resin (A) and 42-65 wt.% of a specified surface hardness improver (B).

Description

  The present invention relates to a polycarbonate resin composition excellent not only in surface hardness but also in transparency, rigidity and warpage.

Polycarbonate resins are thermoplastic resins that are excellent in transparency, heat resistance, thermal stability, and the like, and are therefore used for electrical and electronic component casings and automotive interior materials.

  Polycarbonate resin is expected to be used as a cover for display parts of electrical and electronic equipment, as a substitute for plate glass used in automobiles and building materials because of its transparency. Since the hardness is low, the molded product obtained from the polycarbonate resin has a drawback of being easily damaged.

Until now, in order to improve the rigidity of the polycarbonate resin composition, a method of adding glass fibers that reinforce the polycarbonate resin has been proposed. However, since the refractive index of the added glass fiber material (example: refractive index of E glass at a wavelength of 589 nm: 1.555) and the refractive index of the polycarbonate resin (1.580-1.590) are significantly different, polycarbonate When glass fiber is added to the resin, it is difficult to maintain the transparency of the composition due to the difference in refractive index between the two, and because the glass fiber is a fibrous filler, it is caused by a characteristic called anisotropy of the molded product. That is, there is a problem that warpage occurs in a molded product due to a difference in molding shrinkage rate between the flow direction and the direction perpendicular to the flow.

For such problems, by improving the glass fiber component composition, the refractive index of the glass fiber is improved to the same level as that of the polycarbonate resin, and the transparency of the glass fiber reinforced polycarbonate resin molded product is maintained. It is being considered.

For example, Patent Document 1 proposes a polycarbonate resin composition that maintains transparency by blending glass fibers in which the refractive index of glass fibers is approximately the same as that of polycarbonate resin by blending specific inorganic components. However, there is no description about improving the surface hardness.

Further, in order to improve the scratch resistance (surface hardness) of the polycarbonate resin molded product, a method of coating the surface of the polycarbonate resin with an ultraviolet curable resin has been proposed. However, this method has a problem that due to the flexibility derived from the polycarbonate resin, the pencil hardness requirement 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 2 and Patent Document 3). However, the resin compositions described in these documents have a problem that the surface hardness is high but the hue is lowered. In addition, there is no description on improving the warpage of the molded product.

Japanese Patent No. 5013798 JP 2009-280713 A JP 2010-116501 A

The present invention solves the above-mentioned problems, that is, a polycarbonate resin that can exhibit stable dimensionality that is excellent not only in surface hardness but also in rigidity and without causing warpage as much as possible while maintaining the transparency inherent in the polycarbonate resin. An object is to provide a composition.

As a result of intensive studies to solve the above problems, the present inventors have used not only surface hardness but also rigidity while maintaining transparency by using a specific surface hardness improver and glass flakes. The inventors have found that an excellent polycarbonate resin composition can be obtained, and have completed the present invention.

That is, this invention contains 5-20 weight part of glass flakes (C) per 100 weight part of resin components which consist of 35-58 weight% of polycarbonate resin (A) and 42-65 weight% of surface hardness improvers (B). 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 a copolymer is 5000-30000, It is related with the polycarbonate resin composition characterized by the above-mentioned.

  The polycarbonate resin composition according to the present invention drastically improves not only the surface hardness but also the rigidity and stable dimensionality in which warpage hardly occurs while maintaining the excellent transparency inherent in the polycarbonate resin. . The polycarbonate resin composition of the present invention can be used as, for example, a cover for a display part of an electric device or an electronic device, a substitute for a plate glass used in an automobile or a building material, and the product can be reduced in weight. Furthermore, it is possible to suppress the occurrence of problems such as the falling of a heavy object onto a product made of a molded article made of a polycarbonate resin composition and the occurrence of cracks when the product itself falls.

  Hereinafter, the present invention will be described in detail.

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 (commonly referred to as 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 may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4′-dihydroxydiphenyl, and the like may be used in combination.

  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 not particularly limited, but is usually in the range of 10,000 to 100,000, more preferably 14,000 to 30,000, and even more preferably 16,000 to 26,000 in terms of moldability and strength. Moreover, when manufacturing this polycarbonate resin, a molecular weight modifier, a catalyst, etc. can be used as needed.

The compounding quantity of polycarbonate resin (A) is 35 to 58 weight%. If it exceeds 58% by weight, the surface hardness is inferior, and if it is less than 35% by weight, the transparency is inferior. The preferred blending amount is 45 to 58% by weight, more preferably 45 to 50% by weight.

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.

The compounding amount of the surface hardness improver (B) is 42 to 65% by weight. If it exceeds 65% by weight, the transparency is inferior, and if it is less than 42% by weight, the surface hardness is inferior. A preferable blending amount is 42 to 55% by weight, and more preferably 42 to 50% by weight.

The glass flakes (C) used in the present invention are irregular plate-like glass fillers, and any glass flakes that are usually used in thermoplastic resins can be used.
The glass used in the glass flakes is preferably alkali-free glass (E glass, refractive index at a wavelength of 589 nm: around 1.555), and the maximum diameter of the glass flakes is preferably 30 to 140 μm, and a thickness of 3 to 7 μm is generally used. ing. Further, the number average maximum diameter of the glass flakes is preferably 60 to 120 mm. These are produced according to any conventionally known method.

If the number average maximum diameter is 30 μm or less, the mechanical strength is not sufficiently improved, and if it exceeds 140 μm, glass flakes are scattered in the course of the granulation process, and stable granulation workability cannot be obtained. The thickness of the glass flake (C) is 5 μm, and the number average maximum diameter is more preferably 80 to 100 μm.

The glass flake (C) can be surface-treated with a silane coupling agent such as aminosilane or epoxysilane for the purpose of improving the adhesion to the polycarbonate resin. Further, when glass flakes are handled, the glass flakes can be focused by a bundling material such as urethane or epoxy for the purpose of improving the handleability.

The compounding quantity of glass flake (C) is 5 to 20 weight%. If it is 5% by weight or less, it is not preferable because it is inferior in rigidity, and if it exceeds 20% by weight, it is not preferable because it is inferior in transparency. A preferable blending amount is 5 to 15% by weight, and more preferably 5 to 10% by weight.

Furthermore, various resins, antioxidants, fluorescent brighteners, pigments, dyes, carbon black, fillers, mold release agents, ultraviolet absorbers are added to the polycarbonate resin composition of the present invention within the range not impairing the effects of the present invention. , Antistatic agents, rubber, softeners, spreading agents (liquid paraffin, epoxidized soybean oil, etc.), flame retardants, additives such as organic metal salts, polytetrafluoroethylene resin for preventing dripping, etc. .

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. Two or more kinds may be used in combination.

Examples of the antioxidant include phosphorus antioxidants and phenolic antioxidants. Of these, hindered phenolic antioxidants are preferably used. For example, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], thiodiethylene-bis [ Examples include 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate. In particular, a compound represented by the following structural formula is preferably used. Examples of the antioxidant include Irganox 1076 manufactured by BASF.

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 (manufactured by Sumika Stylon Polycarbonate, Caliber 200-20, viscosity average molecular weight 19000, 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, it is abbreviated as “B component”. )
Glass flake (C)
(Nippon Sheet Glass REFG313 average maximum diameter 140μm, thickness 5μm,
Hereinafter, it is abbreviated as “G-Flake”. )

(Preparation of polycarbonate resin composition pellets)
The above-mentioned various blending components are collectively put into a tumbler at the blending ratios shown in Tables 1 and 2, and after dry mixing for 10 minutes, using a twin screw extruder (KTX37 manufactured by Kobe Steel), a melting temperature of 250 It knead | mixed at (degreeC) and the pellet of the polycarbonate resin composition was obtained.

(Evaluation of transparency of molded products)
The pellets of the various resin compositions obtained above were each dried at 120 ° C. for 4 hours, and then set to a set temperature of 250 ° C. and an injection pressure of 1600 kg / cm 2 using an injection molding machine (Japan Steel Works J-100E-C5). Thus, a test piece for transparency evaluation (50 × 90 × 3, 2, 1 mm (3 thickness) three-stage plate) was prepared. Using the obtained test piece, according to JIS K7361, the light transmittance of the test piece thickness of 2 mm was measured, and the total light transmittance was 80% or more and the haze was 40% or less.

(Evaluation of warpage of molded products)
The pellets of the various resin compositions obtained above were each dried at 120 ° C. for 4 hours, and then set to a set temperature of 250 ° C. and an injection pressure of 1600 kg / cm 2 using an injection molding machine (Japan Steel Works J-100E-C5). Thus, a test piece for dimensional evaluation (plate of 150 × 90 × 3 mm) was prepared. Measure the molding shrinkage rate in the flow direction and in the direction perpendicular to the flow direction of the test piece obtained, and divide the molding shrinkage rate in the flow direction by the molding shrinkage rate in the direction perpendicular to the flow to determine the anisotropy of the molding shrinkage rate. It was sex. A warp property of 0.85 or more was considered good.

(Evaluation of flexural modulus of molded product)
The pellets of the various resin compositions obtained above were each dried at 120 ° C. for 4 hours, and then set to a set temperature of 250 ° C. and an injection pressure of 1600 kg / cm 2 using an injection molding machine (Japan Steel Works J-100E-C5). A test piece according to the ISO test method was prepared, and the bending elastic modulus (rigidity) was measured according to ISO 178 using the obtained test piece, and the bending elastic modulus was determined to be 3000 MPa or more.

(Pencil hardness)
The pellets of the various resin compositions obtained above were dried at 120 ° C. for 4 hours, respectively, and then set at a set temperature of 250 ° C. and an injection pressure of 1600 kg / cm ² using an injection molding machine (Japan Steel Works J-100E-C5). The test piece for pencil hardness evaluation (150x90x2.0mm) was created. Using the obtained test piece, the pencil hardness at which no scratches were observed on the surface of the test piece was determined with a pencil hardness measuring machine (pencil scratch coating film hardness tester manufactured by Toyo Seiki Co., Ltd.) according to JISK5600-5-4. . This pencil hardness was used as an evaluation of surface hardness, and H or higher was considered good.

判定： ○：良好 ×：不良

Judgment: ○: Good ×: Bad

As shown in Examples 1 and 2, 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, the blending amount of the B component (surface hardness improver) and the G-Flake (glass flake) were less than the specified amount, and the pencil hardness and the flexural modulus were poor.
Comparative Example 2 was a case where the blending amount of G-Flake (glass flake) was less than the specified amount, and the flexural modulus was poor.
In Comparative Example 3, the blending amount of the component B (surface hardness improver) was larger than the specified amount and the amount of G-Flake (glass flake) was small, and the flexural modulus was poor.
In Comparative Example 4, there were many G-Flakes (glass flakes), and the dimensionality, total light transmittance, and haze were poor.

Claims (3)

Polycarbonate resin composition comprising 5 to 20 parts by weight of glass flakes (C) per 100 parts by weight of a resin component comprising 35 to 58% by weight of polycarbonate resin (A) and 42 to 65% by weight of surface hardness improver (B) 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 of the copolymer A polycarbonate resin composition having a molecular weight of 5,000 to 30,000. 2. The polycarbonate resin composition according to claim 1, wherein the resin component comprises 45 to 58 wt% of a polycarbonate resin (A) and 42 to 55 wt% of a surface hardness improver (B). 2. The polycarbonate resin composition according to claim 1, wherein the glass flake (C) has a number average maximum diameter of 30 to 140 μm and a thickness of 3 to 7 μm.