JP2005048154A - Light-scattering thermoplastic resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a light-scattering thermoplastic resin composition that has good fluidity and gives a molded product excellent in light scattering properties, heat resistance, or the like. <P>SOLUTION: This light-scattering thermoplastic resin composition comprises (A) 70-90 wt% aromatic polycarbonate, (B) 3-15 wt% copolymer comprising an aromatic vinyl monomer component and a vinyl cyanide monomer component and (C) 5-15 wt% copolymer comprising an aromatic vinyl monomer component, a vinyl cyanide monomer component and a rubber polymer component wherein the total light transmittance of the molded product of 3 mm in thickness formed from the resin composition is in the range of 45-70 %. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light-scattering thermoplastic resin composition from which a molded article having good fluidity, excellent light scattering properties, heat resistance, and the like is obtained, and the molded article thereof.

  Aromatic polycarbonate resins are tough engineering thermoplastic resins with good impact resistance, but are generally known to be difficult to process due to their low fluidity. Various attempts have been made in the past to blend other polymeric modifiers in order to improve the fluidity of the aromatic polycarbonate resin while maintaining its toughness and impact resistance.

Patent Documents 1 and 2 and Non-Patent Document 1 propose low-cost resin compositions by blending ABA (acrylonitrile-butadiene-styrene copolymer) with an aromatic polycarbonate.

  In patent document 3, the resin composition which improved the impact resistance of the molded object obtained from the composition which consists of an aromatic vinyl compound by using an aromatic polycarbonate with a weight average molecular weight of 35,000 or more as an aromatic polycarbonate. Things have been proposed.

  In Patent Document 4, the flowability and impact resistance are improved by specifying the molecular weight of the aromatic polycarbonate above a certain level and limiting the molecular weight of the aromatic vinyl-vinyl cyanide resin forming the dispersed phase to a specific range. Resin compositions have been proposed.

In Patent Document 5, fluidity and ductility are improved by a resin composition blended with an aromatic polycarbonate resin, an acrylonitrile-butadiene-styrene graft copolymer, and an acrylonitrile-styrene copolymer having a reduced acrylonitrile-styrene oligomer content. It has been proposed to let

  Further, it is generally known that the resin composition of aromatic polycarbonate and ABS is black because of the rubber contained in ABS. In this case, as ABS to be blended with the aromatic polycarbonate, ABS having a small rubber particle diameter is used, and if the addition amount is reduced, it becomes almost transparent, but fluidity is impaired.

  On the other hand, the hue of the resin composition of aromatic polycarbonate and acrylonitrile-styrene copolymer becomes opaque because the refractive index of each resin is different. If the weight ratio of the acrylonitrile-styrene copolymer to be added is lowered in order to increase transparency, the rigidity and chemical resistance of the molded article are impaired.

In patent document 5, although the fluidity | liquidity is improved by using a low weight average molecular weight body as an aromatic polycarbonate and an acrylonitrile styrene copolymer, the fall of a heat deformation temperature is caused, and the resin composition of FIG. There is no mention of hue or transparency.
US Pat. No. 3,130,177 Japanese Patent Publication No.38-15225 JP-A-2-129260 JP-A-8-127686 JP-T-2002-528589 Plastics World November 1977, p5-58

  The present invention is a light-scattering thermoplastic resin composition that has a good fluidity, can maintain a good balance of chemical resistance, heat resistance, impact resistance, etc., and can obtain a molded article that is translucent and easily scatters light, and It is an object to provide the molded body.

  The present inventor can set the total light transmittance of the obtained molded product within a predetermined range by selecting the optimal composition of the resin composition as follows. The present inventors have found that the molded product can be imparted with a translucent property that easily scatters light.

As a means for solving the problems, the present invention provides (A) an aromatic polycarbonate of 70 to 90% by weight, and (B) a copolymer containing an aromatic vinyl monomer component and a vinyl cyanide monomer component of 3 to 15% by weight. (C) a resin composition containing 5 to 15% by weight of a copolymer containing an aromatic vinyl monomer component, a vinyl cyanide monomer component and a rubber polymer component,
Provided are a light-scattering thermoplastic resin composition having a total light transmittance of 45 to 70% in a molded product having a thickness of 3 mm, and a molded product thereof.

The composition of the present invention has good fluidity, and the molded product has excellent mechanical strength such as tensile strength, bending strength, bending elastic modulus, impact strength, and heat resistance. Furthermore, since the molded body can exhibit light scattering properties without lowering the light transmittance, it can be imparted with the property that the entire body can shine even with light from a light source such as an LED (light emitting diode). For this reason, when applied to flips, antennas, car audio switches, ornaments, etc. of cellular phones and PDAs (personal portable terminals), operations in the dark can be remarkably improved.

The manufacturing method of the aromatic polycarbonate as the component (A) is not limited, and various types can be used. For example, it can be obtained by a phosgene method in which a known acid acceptor is reacted with a carbonate precursor such as a dihydric phenol in a solvent such as methylene chloride, or a melt transesterification method in which a dihydric phenol and diphenyl carbonate are not used. An aromatic polycarbonate resin is mentioned.
Examples of the dihydric phenol include bisphenols, and 2,2-bis (4-hydroxyphenyl) propane is particularly preferable.

  The aromatic polycarbonate as component (A) preferably has a weight average molecular weight of 38,000 to 53,000 from the viewpoint of mechanical strength and moldability, and the weight average molecular weight is preferably in the range of 40,000 to 50,000. Are more preferred. In addition, in this invention, a weight average molecular weight is the value calculated | required by standard polystyrene conversion using THF as a solvent using gel permeation chromatography.

  The component (B) is a copolymer containing an aromatic vinyl monomer component and a vinyl cyanide monomer component.

  Examples of the aromatic vinyl monomer component include styrene, α-methylstyrene, para-methylstyrene, vinylxylene, dibromostyrene, fluorostyrene, ethylstyrene, vinylnaphthalene, and preferably styrene. The aromatic vinyl monomer component may be a mixture of two or more.

Examples of the vinyl cyanide monomer component include acrylonitrile and methacrylonitrile, and acrylonitrile is preferred. The vinyl cyanide monomer component may be a mixture of two or more.

  (B) Content of the aromatic vinyl monomer component in a component becomes like this. Preferably it is 65 to 80 weight%, More preferably, it is 65 to 77 weight%, More preferably, it is 70 to 75 weight%.

  (B) Content of the vinyl cyanide monomer component in a component becomes like this. Preferably it is 40-20 weight%, More preferably, it is 35-23 weight%, More preferably, it is 30-25 weight%.

  In the component (B), when the content of the aromatic vinyl monomer component and the vinyl cyanide monomer component is within the above range, the chemical resistance of the molded body is improved and the fluidity of the composition is also improved. There is no coloring of the molded body.

  The copolymer of the component (B) preferably has a weight average molecular weight (Mw) in the range of 90,000 to 180,000 from the viewpoint of mechanical strength and chemical resistance, and among them, the weight average molecular weight is 90,000. A range of ˜170,000 is more preferred.

  Preferable examples of the copolymer as component (B) include acrylonitrile-styrene copolymers.

  As a method for producing the copolymer of component (B), bulk polymerization, solution polymerization, bulk suspension polymerization, suspension polymerization, emulsion polymerization, etc. are used, but there are few impurities such as residual solvent, dispersant, emulsifier, etc. Alternatively, an acrylonitrile-styrene copolymer of a bulk polymerization method substantially not containing is preferable.

  If the solvent, dispersant, emulsifier, etc. used in solution polymerization, bulk suspension polymerization, suspension polymerization, emulsion polymerization, etc. are included, the characteristics of the copolymer of component (B) (heat distortion temperature, elastic modulus) In addition to adversely affecting the heat resistance, when the composition is produced, the heat resistance stability is lowered due to these influences, and coloring is not preferable.

  Component (C) is a copolymer including an aromatic vinyl monomer component, a vinyl cyanide monomer component, and a rubber polymer component.

  Examples of the aromatic vinyl monomer component include styrene, α-methylstyrene, para-methylstyrene, vinylxylene, dibromostyrene, fluorostyrene, ethylstyrene, vinylnaphthalene, and preferably styrene. The aromatic vinyl monomer component may be a mixture of two or more.

  Examples of the vinyl cyanide monomer component include acrylonitrile and methacrylonitrile, and acrylonitrile is preferred. The vinyl cyanide monomer component may be a mixture of two or more.

  Examples of the rubbery heavy component include polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, polyisoprene, and preferably polybutadiene. The rubbery polymer may be a mixture of two or more.

  The content of the rubbery polymer component in the component (C) is preferably 3 to 30% by weight, more preferably 8 to 25% by weight, and still more preferably 10 to 22% by weight. When the content of the rubbery polymer component is 3% by weight or more, the impact resistance of the molded product obtained from the composition is improved, and when it is 30% by weight or less, the fluidity of the composition is improved.

  As the method for producing the copolymer of component (C), for example, bulk polymerization, suspension polymerization, emulsion polymerization, bulk-suspension polymerization, etc. are used. Alternatively, a bulk polymerization process that is substantially free of is optimal.

  If the dispersant, emulsifier, etc. used in the bulk polymerization method, suspension polymerization method, emulsion polymerization method, bulk-suspension polymerization method, etc. are contained, the mechanical properties of the copolymer (C) (impact resistance) Not only adversely affects the property), but also when the composition is produced, the heat resistance stability is reduced due to these effects, and burning occurs.

  The particle diameter of the dispersed rubber phase of the copolymer (C) is preferably 10 μm or less, more preferably 10 μm to 0.1 μm, and still more preferably 5 μm to 0.1 μm. When the particle diameter is 10 μm or less, the molded product obtained from the composition has high transparency, and can give a predetermined total light transmittance.

  The grafting rate of the copolymer of component (C) is preferably 20 to 66%, more preferably 20 to 28%, and still more preferably 20 to 25%. When the grafting rate is 20% or more, the impact resistance of the molded product obtained from the composition is improved, and when it is 60% or less, the fluidity of the composition is lowered.

  Various additives such as a lubricant, a release agent, an antistatic agent, a flame retardant, and a colorant can be appropriately combined and added to the composition of the present invention within a range that can solve the problems of the present invention.

  The composition of the present invention has a total light transmittance of 45 to 70%, preferably 48 to 65%, more preferably 50 to 63% in a molded product having a thickness of 3 mm. When the total light transmittance is 45% or more, moderate transparency and light scattering can be imparted to the molded product obtained from the composition.

  In the composition of the present invention, the rubber content of the whole composition is preferably 0.8 to 1.95% by weight, more preferably 0.85 to 1.95% by weight, and still more preferably 0.9 to 1. 95% by weight. When the rubber content is 0.8% by weight or more, the impact resistance of the molded product obtained from the composition is improved, and when it is 1.95% by weight or less, a predetermined total light transmittance is imparted to the molded product. it can.

  The composition of the present invention is obtained by appropriately weighing and mixing the components (A), (B), (C) and other additives. The composition can be formed into a desired molded body as it is by dry blending, but is preferably melt-mixed into a granular material such as pellets.

  The composition of the present invention is applied to various molding methods such as an injection molding method, an extrusion molding method, a thermoforming method, etc., for example, flips of mobile phones and PDAs (personal portable terminals), parts such as antennas, lighting covers, etc. Can be molded into car audio switches, ornaments, etc.

(1) Components used (A) Component PC: Polycarbonate, S2000F (weight average molecular weight 44,000, manufactured by Mitsubishi Engineering Plastics)
(B) Component AS-1: Acrylonitrile-styrene copolymer by bulk polymerization (weight average molecular weight 150,000; acrylonitrile content 25% by weight, manufactured by Daicel Chemical Industries, Ltd.)
AS-2: Acrylonitrile-styrene copolymer by bulk polymerization (weight average molecular weight 150,000; acrylonitrile content 30% by weight, manufactured by Daicel Chemical Industries, Ltd.)
(C) Component ABS-1: Acrylonitrile-butadiene-styrene copolymer by emulsion polymerization, DP611 (manufactured by Technopolymer Co., Ltd.)
ABS-2: Acrylonitrile-butadiene-styrene copolymer by bulk polymerization, AT05 (manufactured by Nippon A & L Co., Ltd.)
Other components Heat resistance stabilizer: hindered phenol heat resistance stabilizer and phosphorus heat resistance stabilizer (2) Measuring method [Particle size of dispersed rubber phase]
The sliced specimen is etched and wrapped with a photo-curable epoxy resin. After photo-curing, an ultrathin section is created with a cryomicrotome, stained with ruthenium tetroxide, and the rubber particle size of this section is transmitted. It measured with the electron microscope and calculated | required the average value of 3 pieces.

[Total amount of rubber in the composition]
Calculated from the rubber content in the ABS.

[MFR]
The measurement was performed at 240 ° C. and a load of 5 kg.

〔Tensile strength〕
Using a test piece having a thickness of 4 mm, measurement was performed according to ISO 529 using UCT-1T (Orientec Co., Ltd.).

[Bending strength]
Using a test piece having a thickness of 4 mm, measurement was performed according to ISO178 with UTM-5T (manufactured by Toyo Baldwin Co., Ltd.).

(Bending elastic modulus)
Using a test piece having a thickness of 4 mm, measurement was performed according to ISO178 with UTM-5T (manufactured by Toyo Baldwin Co., Ltd.).

[Heat deformation temperature (HDT)]
Using a test piece having a thickness of 4 mm, measurement was performed according to ISO75 using UTM-5T (manufactured by Toyo Baldwin Co., Ltd.).

[Charpy impact strength]
Using a test piece having a thickness of 4 mm, measurement was performed according to ISO 179 with a Charpy impact tester (manufactured by Toyo Seiki Co., Ltd.).

[Total light transmittance]
Measurement was performed with a haze meter HGM-2D (manufactured by Suga Test Instruments Co., Ltd.) using a test piece having a thickness of 3 mm.

Examples 1 to 4, Comparative Examples 1 and 2
After mixing each component shown in Table 1 (numerical values are expressed in parts by weight. However, the heat stabilizer is expressed in parts by weight with respect to 100 parts by weight of the total of the components (A), (B), and (C)). In addition to the hopper of a twin screw extruder (TEM35B manufactured by Toshiba Machine Co., Ltd.), the composition of the present invention was obtained by extrusion at 270 ° C. and pelletizing. This pellet was injection-molded using SH-100 (manufactured by Sumitomo Heavy Industries, Ltd.) to produce the above test pieces for each measurement.

  As is apparent from Table 1, since the fluidity is good, molding by a known molding method such as injection molding is easy. In addition, the molded product obtained from the composition is not colored, has excellent mechanical properties and heat resistance, and has a total light transmittance in the range of 45 to 75%. Therefore, it can be applied to the use as described above. In Comparative Examples 1 and 2, since the total light transmittance is low, transparency and light scattering are not sufficient.

Claims (4)

(A) Aromatic polycarbonate 70 to 90% by weight, (B) 3 to 15% by weight of copolymer containing aromatic vinyl monomer component and vinyl cyanide monomer component, (C) aromatic vinyl monomer A resin composition containing 5 to 15% by weight of a copolymer comprising a component, a vinyl cyanide monomer component and a rubber polymer component;
A light-scattering thermoplastic resin composition having a total light transmittance of 45 to 70% in a molded product having a thickness of 3 mm.   The light scattering according to claim 1, wherein the aromatic vinyl monomer component contained in the copolymer of component (B) is in the range of 65 to 80 wt% and the vinyl cyanide monomer component is in the range of 35 to 20 wt%. Thermoplastic resin composition.   The light scattering thermoplastic resin composition according to claim 1 or 2, wherein the rubber content of the copolymer of component (C) is in the range of 3 to 30% by weight and the particle diameter of the dispersed rubber phase is 10 µm or less. The molded object of the light-scattering thermoplastic resin composition in any one of Claims 1-3.