JP3356885B2 - Polycarbonate resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polycarbonate resin composition. In more detail, without impairing the original physical properties of polycarbonate resin such as impact resistance and heat resistance,
The present invention relates to a polycarbonate resin composition having high light reflectivity.

[0002]

2. Description of the Related Art Conventionally, a plated product obtained by plating a resin molded product has been used as a light reflecting material. However, such plated products are
A complicated plating step is required, which leads to an increase in cost. A light reflecting material which does not need to be plated and has a high light reflectivity in a resin molded product itself is demanded. In recent years, resin molded products that contain titanium oxide and have improved light reflectivity by improving whiteness have been used as backlight reflectors for liquid crystal displays, reflectors for illuminated push switches and photoelectric switches, and displays for vending machines. Used for internal frames, strobe reflectors, etc. As a resin used for such an application, a polycarbonate resin excellent in impact resistance, heat resistance and the like is suitable.

However, since the polycarbonate resin is excellent in transparency, if the amount of titanium oxide is small, the amount of transmitted light is large and the required high light reflectivity cannot be obtained. In addition, when the amount of titanium oxide is increased, there arises a problem that the intrinsic physical properties of the polycarbonate resin such as impact resistance are impaired.

On the other hand, attempts have been made to improve the impact resistance by blending titanium oxide surface-treated with a silane coupling agent into a polycarbonate resin, but none of them still satisfy the required performance. There is no present.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a mixture obtained by melt-mixing a specific titanium oxide fine powder and a styrene-based resin at a specific ratio and a rubber-like mixture. By blending the reinforcing material with the polycarbonate resin, it was found that a polycarbonate resin composition having high light reflectivity can be obtained without impairing the physical properties of the polycarbonate resin such as impact resistance and heat resistance, and completed the present invention. I came to.

[0006]

[Means for Solving the Problems] That is, the present invention provides:
(A) For 100 parts by weight of the polycarbonate resin,
(B) The titanium oxide fine powder (b-1) and the styrene-based resin (b-2) treated with a hydrated oxide of aluminum and / or silicon are melted at a weight ratio of 30:70 to 80:20. A mixture of 5 to 60 parts by weight of a mixture obtained by mixing and 0.1 to 20 parts by weight of a rubber-like reinforcing material (C) is used without impairing the physical properties of polycarbonate resin such as impact resistance and heat resistance. An object of the present invention is to provide a polycarbonate resin composition having light reflectivity.

Hereinafter, the present invention will be described in detail. The polycarbonate resin (A) used in the present invention is a resin obtained by a phosgene method of reacting various dihydroxydiaryl compounds with phosgene, or a transesterification method of reacting a dihydroxydiaryl compound with a carbonate such as diphenyl carbonate. It is coalesced and a typical one is a polycarbonate 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-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 (4-hydroxy-3,
Bis (hydroxyaryl) alkanes such as 5-dichlorophenyl) propane, bis (hydroxyaryl) such as 1,1-bis (4-hydroxyphenyl) cyclopentane and 1,1-bis (4-hydroxyphenyl) cyclohexane Cycloalkanes, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-
Dihydroxydiaryl ethers such as 3,3'-dimethyldiphenylether, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxy-3,
Dihydroxydiaryl sulfides such as 3'-dimethyldiphenyl sulfide, 4,4'-dihydroxydiphenyl sulphoxide, 4,4'-dihydroxy-
Dihydroxydiarylsulfoxides such as 3,3'-dimethyldiphenylsulfoxide; dihydroxydiarylsulfones such as 4,4'-dihydroxydiphenylsulfone; and 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone. Can be

These may be used alone or as a mixture of two or more kinds. In addition, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl and the like may be used in combination.

Further, the above-mentioned dihydroxyaryl compound and a phenol compound having three or more valences as shown below may be mixed and used. 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 10,000 to 100,000, preferably 15,000, in view of moldability and strength.
３５35,000. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as required.

The titanium oxide fine powder used as the component (b-1) in the present invention may be titanium oxide produced by any of a chlorine method and a sulfuric acid method.
Further, in the present invention, a titanium oxide fine powder which has been treated with a hydrated oxide of aluminum and / or silicon is used. The fine powder of titanium oxide is usually 0.1 to 0.5 μm.

The hydrated oxides of aluminum and silicon used in the treatment of titanium oxide include alumina and silica. The treatment with alumina and / or silica does not need to employ any particular method, and may be performed by any method. When the amount given by the treatment is too small, it is difficult to obtain high light reflectivity. When the amount is too large, the physical properties of the polycarbonate resin may be impaired. It is preferable to process within the range. The treating agent used may contain, in addition to alumina and / or silica, a stabilizer, a dispersant and the like within a range that does not impair the object of the present invention.

The styrene resin used as the component (b-2) is a polymer mainly composed of styrene and copolymerized with another copolymerizable monomer as required. Is polystyrene, styrene-acrylonitrile copolymer, α-methylstyrene-acrylonitrile copolymer, styrene-methyl methacrylate copolymer, styrene-acrylonitrile-methyl methacrylate copolymer, styrene-maleic anhydride copolymer, styrene −
Acrylic acid copolymer, styrene-maleimide copolymer,
Styrene-acrylonitrile-maleimide copolymer and the like can be mentioned.

The component (B) in the present invention is obtained by melt-mixing the fine titanium oxide powder (b-1) and the styrene resin (b-2) at a weight ratio of 30:70 to 80:20. It is a mixture consisting of If the component (b-1) is less than 30% by weight, impact resistance and heat resistance are poor, and if it exceeds 80% by weight, melt mixing becomes difficult, which is not preferable. When the titanium oxide fine powder (b-1) and the styrene-based resin (b-2) are melt-mixed, a known kneading machine can be used, but mixing by a kneader is particularly preferable.

The rubber-like reinforcing material (C) used in the present invention may be a diene rubber such as polybutadiene or polyisoprene, an acrylate rubber such as polybutyl acrylate, an olefin rubber such as ethylene-propylene rubber, or a rubber. To which a vinyl compound such as methyl methacrylate or styrene is graft-polymerized. Among these, a graft polymer obtained by grafting methyl methacrylate and styrene onto an acrylate rubber is particularly preferred.

The resin composition of the present invention is prepared by mixing 5 parts of the mixture (B) with 100 parts by weight of the polycarbonate resin (A).
To 60 parts by weight and 0.1 to 20 parts by weight of the rubber-like reinforcing material (C). If the amount of the mixture (B) is less than 5 parts by weight, the light reflectivity is inferior. If the amount exceeds 60 parts by weight, no further improvement in the light reflectivity can be expected, and physical properties such as impact resistance are rather deteriorated. . If the rubber-like reinforcing material is less than 0.1 part by weight, the impact resistance is poor, and if it exceeds 20 parts by weight, heat resistance, rigidity and, in some cases, delamination occur, which is not preferable.

The method of mixing the components (A), (B) and (C) and the order of mixing are not particularly limited, and the three components are mixed simultaneously or any two components are mixed, and then the remaining component is mixed. May be. In addition, upon mixing, melt kneading is performed using a known mixer such as a Banbury mixer, a roll, or an extruder.

Further, at the time of mixing, if necessary, known additives such as fillers, antistatic agents, release agents, antioxidants,
UV absorbers, flame retardants, dyes and pigments, etc. can be added.

[Examples] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, the physical property in an Example was measured by the following method.

Impact resistance : According to ASTM D-256,
Izod impact strength was measured. The thickness of the test piece is 1/8 inch, and the unit is Kg · cm / cm.

Tensile strength : According to ASTM D-790
The tensile strength was measured. Test piece thickness 1/8 inch, unit K
g / cm ² .

Heat resistance : The deflection temperature under load was measured in accordance with ASTM D-648. Test specimen thickness 1/4 inch, load 18.6 kg / cm ² , unit ° C.

Light reflectivity : Using a spectrophotometer (CMS-35SP) manufactured by Murakami Color Co., Ltd., wavelength: 400 to 800 n.
The Y value at m was measured. Those that are 91% or more are judged to be acceptable.

Preparation of component (B) : titanium oxide shown in Table 1 and acrylonitrile obtained by a known suspension polymerization method
A styrene (AS) copolymer (copolymerization ratio 30/70) was pelletized at a ratio shown in Table 2 by a kneader at a melt mixing temperature of 220 ° C. In addition, about b-1, it was not able to pelletize.

The component (A) has a viscosity average molecular weight of 23,
Table 3 shows the polycarbonate resin of No. 000, the component (B) and the methyl methacrylate-styrene grafted acrylic rubber (W-800 manufactured by Mitsubishi Rayon) as the component (C), or the AS copolymer and titanium oxide as comparative examples. After mixing in a blender at a ratio, the mixture was extruded at a cylinder temperature of 250 ° C. by a single screw extruder (VS40-32 manufactured by Tanabe Seisakusho) and pelletized. After drying the pellets at 125 ° C. for 4 hours, various test pieces were molded using a 4-ounce injection molding machine.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 1]

[0030]

Industrial Applicability The polycarbonate resin composition of the present invention is excellent in light reflectivity without impairing the inherent physical properties of polycarbonate resin such as impact resistance and heat resistance. Can be suitably used for applications requiring light reflectivity.

Continuation of the front page (56) References JP-A-4-161448 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 69/00

Claims (1)

(57) [Claims] 1. (B) 100 parts by weight of a polycarbonate resin, (B) titanium oxide fine powder (b-1) treated with a hydrated oxide of aluminum and / or silicon, and styrene resin (b-2) 30: 70-8 by weight
A polycarbonate resin composition comprising 5 to 60 parts by weight of a mixture obtained by melting and mixing at a ratio of 0:20 and (C) 0.1 to 20 parts by weight of a rubber-like reinforcing material.