JP2008081581A - Thermoplastic resin composition and exterior component for motor vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition excellent in weatherability and also in impact resistance, chemical resistance and mechanical properties, and suitable to design components including door handles, pillars, side moldings, side protectors and automotive interior switches, and to provide exterior components for motor vehicles. <P>SOLUTION: The thermoplastic resin composition is such as to be obtained by compounding 0.01-1.9 pts.wt. of a titanium oxide (D) 0.10-0.25 μm in an average particle size to 100 pts.wt. of a resin component comprising 25-55 wt.% of a polybutylene terephthalate resin (A), 40-70 wt.% of a polycarbonate resin (B) and 0.5-20 wt.% of a rubbery polymer (C). In this resin composition, it is characterized in that the polybutylene terephthalate resin and the polycarbonate resin form a double-phase continuous structure 0.001-1.0 μm in structural period or a disperse structure of 0.001-1.0 μm in particle-particle distance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermoplastic resin composition comprising polybutylene terephthalate and polycarbonate resin, the weather resistance of which has been improved by titanium oxide, and a vehicle exterior part obtained therefrom.

  Conventionally, blends of polybutylene terephthalate resin and polycarbonate resin are widely used as engineering plastics because of their excellent mechanical properties, heat resistance, chemical resistance, and the like. Further, in recent years, in order to improve impact resistance and rigidity, those containing a fine inorganic filler such as rubber polymer, glass fiber, talc, mica, whisker or the like are widely used. Furthermore, a composition having improved mechanical properties such as heat resistance, chemical resistance and impact resistance is desired.

  A composition comprising a polybutylene terephthalate resin and a polycarbonate resin having a specific structural period is known (Patent Document 1). A composition in which titanium oxide and an elastic copolymer are blended with a composition comprising a polybutylene terephthalate resin and a polycarbonate resin is also known (Patent Document 2). Furthermore, a resin composition in which fine titanium oxide is blended with a composition comprising polybutylene terephthalate resin and polycarbonate resin is also known (Patent Document 3). Titanium oxide is blended with a composition comprising polybutylene terephthalate resin and polycarbonate resin. A resin composition is also known (Patent Document 5).

However, in the case where the resin composition described in Patent Document 1 is used, the weather resistance is insufficient, and in the case where the resin composition described in Patent Document 2 is used, the resin composition described in Patent Document 1 is used. The weather resistance is better than that of the product, but it has the disadvantage that the impact resistance, chemical resistance and mechanical properties are not sufficient. When the resin composition described in Patent Document 3 is used, the weather resistance is better than that of the resin composition described in Patent Document 1, but the impact resistance, chemical resistance, and mechanical properties are not sufficient. Moreover, in order to use fine particle titanium oxide, masterbatch is required beforehand and there exists a disadvantage that a process increases. In the case where the resin composition described in Patent Document 4 is used, the weather resistance is better than that of the resin composition described in Patent Document 1, but there is a drawback that impact resistance, chemical resistance, and mechanical properties are not sufficient. Have.
JP 2003-286414 A (Claims) Japanese Patent Laid-Open No. 04-306256 (Claims) Japanese Patent Laid-Open No. 06-329891 (Claims) Japanese Patent Application Laid-Open No. 07-242804 (Claims)

  Then, this invention is providing the thermoplastic resin composition which is excellent in a weather resistance, and has an impact resistance, chemical resistance, and the outstanding mechanical characteristic.

  The present invention has been obtained as a result of intensive studies by the present inventors in order to solve the above problems.

That is, the present invention
(1) Polybutylene terephthalate resin (A) 25 to 55% by weight, polycarbonate resin (B) 40 to 70% by weight, rubber polymer (C) 100 parts by weight of resin component, 0.01 to 1.9 parts by weight of titanium oxide (D) having an average particle diameter of 0.10 to 0.25 μm is blended, and the polybutylene terephthalate resin (A) and the polycarbonate resin (B) have a structural period of 0. A thermoplastic resin composition characterized by forming a double-phase continuous structure of 0.001 to 1.0 μm or a dispersed structure having a distance between particles of 0.001 to 1.0 μm,
(2) Titanium oxide (D) is a rutile crystalline form produced by the chlorine method with the addition of a treatment agent containing alumina hydrate and silicic acid hydrate, and is obtained. And the thermoplastic resin composition according to (1),
(3) Provided is a vehicle exterior component comprising the thermoplastic resin composition described in (1) or (2).

  The thermoplastic resin composition of the present invention has excellent weather resistance and can have both impact resistance, chemical resistance and mechanical properties. In addition, the thermoplastic composition of the present invention can be suitably used as exterior parts for vehicles such as door handles, pillars, side moldings, side protectors and the like.

  Hereinafter, the present invention will be described in detail.

  The polybutylene terephthalate resin (A) constituting the present invention is a normal polymerization such as a polycondensation reaction mainly comprising terephthalic acid or an ester-forming derivative thereof and 1,4-butanediol or an ester-forming derivative thereof. It is a polymer obtained by the method, and may contain other copolymerization components in a range that does not impair the characteristics, for example, about 20 parts by weight or less. Preferred examples of these polymers and copolymers include polybutylene terephthalate, polybutylene (terephthalate / isophthalate), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene. (Terephthalate / Naphthalate), poly (butylene / ethylene) terephthalate and the like may be mentioned, and these may be used alone or in combination of two or more.

  The polybutylene terephthalate used in the present invention preferably has an intrinsic viscosity of 0.60 to 1.60, particularly 0.80 to 1.30 when an o-chlorophenol solution is measured at 25 ° C. is there. If the intrinsic viscosity is less than 0.60, the mechanical properties are poor. On the other hand, if the intrinsic viscosity exceeds 1.60, the moldability tends to be poor.

  The blending amount of polybutylene terephthalate in the present invention is 25 to 55% by weight of the resin component. When the blending amount of polybutylene terephthalate is less than 25% by weight, the chemical resistance of the resin composition is inferior, and when it exceeds 55% by weight, the impact strength of the resin composition tends to decrease.

  The polycarbonate resin (B) constituting the present invention is a polymer obtained by reacting a dihydric phenol with a carbonate precursor such as phosgene or a carbonate ester compound, for example, in a solvent such as methylene chloride. It is produced by a reaction between a dihydric phenol and a carbonate precursor such as phosgene, or by a transesterification reaction between a dihydric phenol and a carbonate precursor such as diphenyl carbonate. There are various dihydric phenols, and 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] is particularly preferable. Divalent phenols other than bisphenol A include bis (4-hydroxyphenyl) alkane, 1,1- (4-hydroxyphenyl) methane, 1,1- (4-hydroxyphenyl) ethane, hydroquinone, bis (4-hydroxy Phenyl) cycloalkane, bis (4-hydroxyphenyl) oxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) ether, etc. Is mentioned. These dihydric phenols may be used alone or in combination of two or more. Examples of the carbonate compound include diaryl carbonates such as diphenyl carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate.

  As the polycarbonate resin (B) used in the present invention, those having an average molecular weight in the range of 10,000 to 60,000, particularly 15,000 to 40,000 are suitable. If the average molecular weight is less than 10,000, the mechanical properties are poor. On the other hand, if the average molecular weight exceeds 60000, the moldability tends to be poor.

  The compounding quantity of polycarbonate resin (B) in this invention is 40 to 70 weight% of a resin component. When the blending amount of the polycarbonate resin (B) is less than 40% by weight, the impact strength of the resin composition tends to be lowered, and when it exceeds 70% by weight, the chemical resistance is lowered, or at the time of injection molding of the resin composition. The mold release property and fluidity are poor and the molding high cycle property tends to be inferior.

  Furthermore, in the present invention, it is essential to use the rubbery polymer (C) in order to improve the impact strength. Such a rubbery polymer is a resin that exhibits rubber elasticity at room temperature, and is a polybutadiene, polyisobrene, random copolymer of styrene-butadiene and a block copolymer, a hydrogenated product of the block copolymer, acrylonitrile-butadiene. Copolymers, diene rubbers such as butadiene-isoprene copolymers, ethylene-propylene random copolymers and block copolymers, ethylene-butene random copolymers and block copolymers, and ethylene-α olefins Copolymers, copolymers with ethylene-unsaturated carboxylic esters such as ethylene-methacrylate, ethylene-butyl acrylate, acrylic ester-butadiene copolymers, for example acrylic rubbers such as butyl acrylate-butadiene copolymers, etc. Can be mentioned. Particularly, bulk polymerization, suspension polymerization, bulk suspension polymerization, solution of one or more of methacrylic acid ester, aromatic monovinyl compound, and vinyl cyanide compound to butadiene rubber-like polymer such as polybutadiene and butadiene-styrene copolymer An MBS resin obtained by graft polymerization by a method such as polymerization or emulsion polymerization, particularly an emulsion polymerization method is preferred.

  The blending amount of the rubbery polymer (C) in the present invention is 0.5 to 20% by weight, preferably 0.5 to 10% by weight of the resin component. When the blending amount of the rubber polymer (C) is less than 0.5% by weight, the impact strength is insufficient, and when it exceeds 20% by weight, the chemical resistance is lowered or the mold release at the time of injection molding of the resin composition. The properties are poor and the molding high cycle property tends to be inferior.

  It is essential that the titanium oxide (D) used in the present invention is a titanium oxide having an average particle diameter of 0.10 μm to 0.25 μm, and if it is less than 0.10 μm, the dispersibility is deteriorated and aggregation occurs. When it occurs, the weather resistance decreases, and when it exceeds 0.25 μm, the mechanical properties tend to be poor or the surface appearance tends to deteriorate. The average particle diameter was magnified 50000 times with a scanning electron microscope, the diameter in the longitudinal direction of 100 particles was measured, and the number average was taken as the average particle diameter.

  Titanium oxide (D) used in the present invention is a rutile crystalline form produced by the chlorine method, and has alumina hydrate and silicic acid hydrate on the surface. That is, titanium oxide having a rutile crystal form produced by the chlorine method is preferable, and if it is a titanium oxide having a crystal form other than the rutile form produced by a production method other than the chlorine method, the weather resistance of the molded product is lowered. Tend to. In addition, the titanium oxide is preferably obtained by adding a treatment agent containing alumina hydrate and silicate hydrate. When the surface treatment is not performed, the particle size is increased by secondary aggregation. As a result, the surface appearance of the molded product is lowered, and the mechanical properties tend to be lowered.

  The compounding amount of titanium oxide is 0.01 to 1.9 parts by weight with respect to 100 parts by weight of the resin component, and if it is less than 0.01 parts by weight, the weather resistance of the resin composition is lowered and 1.9 parts by weight. If it exceeds, impact resistance, fatigue properties, chemical resistance, and mechanical properties tend to deteriorate.

  In the present invention, it is essential that the polybutylene terephthalate resin and the polycarbonate resin form a biphasic continuous structure having a structural period of 0.001 to 1.0 μm or a dispersed structure having a distance between particles of 0.001 to 1.0 μm. It is. As a method for obtaining a polymer alloy having such a structure, a method utilizing spinodal decomposition described later is preferable.

  In general, polymer alloys composed of two-component resins include compatible systems, incompatible systems, and semi-compatible systems. The compatible system is a system that is compatible in the entire range of practical temperatures above the glass transition temperature and below the thermal decomposition temperature under non-shearing in an equilibrium state. The incompatible system is a system that is incompatible in the entire region, contrary to the compatible system. A semi-compatible system is a system that is compatible in a certain temperature and composition region and incompatible in another region. Furthermore, in this semi-compatible system, there are those that undergo phase separation by spinodal decomposition depending on the conditions of the phase separation state and those that undergo phase separation by nucleation and growth.

  Furthermore, in the case of a polymer alloy comprising three or more components, a system in which all of the three or more components are compatible, a system in which all of the three or more components are incompatible, and a compatible system having two or more components and the rest There is a system in which one or more phases are incompatible with each other, two components are in a semi-compatible system, and the remaining components are distributed in a semi-compatible system composed of these two components.

  In the present invention, in the case of a polymer alloy comprising three or more components other than polybutylene terephthalate resin and polycarbonate resin, the third component other than polybutylene terephthalate resin and polycarbonate resin is at least one of polybutylene terephthalate resin and polycarbonate resin. A distributed system is preferred. In this case, the structure of the polymer alloy is equivalent to the incompatible structure composed of two components. The following description will be made on behalf of a polymer alloy composed of a two-component resin.

In the above incompatible system, it is possible to induce spinodal decomposition by melt kneading. For this purpose, it is once compatible under shear at a shear rate of 100 to 10000 sec ⁻¹ during melt kneading and then under non-shearing. The phases are separated by the so-called shear field-dependent spinodal decomposition in which the phase decomposition occurs. Since the basic part of this shear field-dependent spinodal decomposition mode is the same as the above-described general spinodal decomposition in the semi-compatible system, the spinodal decomposition in the general semi-compatible system is described below, and then the present invention is applied. A description will be given in the form of appending characteristic portions.

  In general, phase separation by spinodal decomposition refers to phase separation that occurs in an unstable state inside the spinodal curve in phase diagrams for different two-component resin compositions and temperatures. On the other hand, phase separation by nucleation and growth refers to phase separation that occurs in the metastable state inside the binodal curve and outside the spinodal curve in the phase diagram.

The spinodal curve refers to the difference (ΔGmix) between the free energy in the case of being compatible and the sum of the free energy in the incompatible phase (ΔGmix) when mixing two different resins with respect to the composition and temperature. This is a curve in which the partial differential of (φ ² ) (∂ ² ΔGmix / ∂φ ² ) becomes zero. Inside the spinodal curve, 不 安定² ΔGmix / ∂φ ² <0 is in an unstable state, and outside the spinodal curve, ∂ ² ΔGmix / ∂φ ² > 0.

  The binodal curve is a curve at the boundary between a region where the system is compatible and a region where it is incompatible with the composition and temperature.

  Here, the compatible state is a state in which they are uniformly mixed at the molecular level. Specifically, the case where the phase which consists of a different component does not form the structure of 0.001 micrometer or more is pointed out. Moreover, an incompatible state is a case where it is not a compatible state. That is, the phase which consists of a different component points out the state which forms the structure of 0.001 micrometer or more. Here, the structure of 0.001 μm or more is, for example, a two-phase continuous structure having a structural period of 0.001 to 1 μm or a dispersed structure having a distance between particles of 0.001 to 1 μm. Whether or not they are compatible is determined by, for example, an electron microscope, a differential scanning calorimeter (DSC), and various other methods as described in Polymer Alloys and Blends, Leszek A Utracki, hanser Publishers, Munich Viema New York, P64. be able to.

In order to realize the spinodal decomposition, it is necessary that the resin having two or more components is once in a compatible state and then in an unstable state inside the spinodal curve. In spinodal decomposition in a general semi-compatible system, spinodal decomposition can be caused by temperature jumping to an incompatible region after melt-kneading under compatible conditions. On the other hand, in the above-mentioned shear field-dependent spinodal decomposition, in the non-compatible system, since it is compatibilized under shear in the range of a shear rate of 100 to 10000 sec ⁻¹ at the time of melt kneading, the spinodal can be obtained only by non-shearing. Degradation can occur.

The polymer alloy formed by blending the polybutylene terephthalate resin and the polycarbonate resin of the present invention belongs to the above-mentioned shear field-dependent spinodal decomposition, and is compatibilized under shear in the range of a shear rate of 100 to 10000 sec ⁻¹ during melt kneading. Only under non-shearing can cause spinodal decomposition. In the above, the shear rate is, for example, when using a parallel disk type shear applicator, a resin heated to a predetermined temperature and put in a molten state is put between the parallel disks, the distance (r) from the center, and between the parallel disks It can be obtained as ω × r / h from the interval (h) and the angular velocity (ω) of rotation.

  As a specific method for producing such a polymer alloy, a method using the above-mentioned shear field-dependent spinodal decomposition is mentioned as a preferred example. As a method for realizing compatibilization during melt-kneading, polybutylene terephthalate resin and polycarbonate resin are used. A preferable method is a method of melt-kneading under high shear stress in the kneading zone of the twin-screw extruder.

  When using such a twin-screw extruder, a higher shear stress state is formed by screw arrangement using a kneading block, lowering the resin temperature, increasing the screw rotation speed, or increasing the viscosity of the polymer used. Therefore, it can be adjusted appropriately.

  In the polyester resin composition of the present invention, a mold release agent, an antioxidant, a stabilizer, an ultraviolet absorber, a colorant, a flame retardant, a flame retardant aid, an impact modifier, within the range not impairing the effects of the present invention. Conventional additives such as lubricants and small amounts of other polymers can be added.

  Release agents include plant waxes such as carnauba wax and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as montan wax, petroleum waxes such as paraffin wax and polyethylene wax, castor oil and its Fatty waxes such as derivatives, fatty acids and derivatives thereof may be mentioned.

  Examples of antioxidants include 2,6-di-t-butyl-4-methylphenol, tetrakis (methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) methane, tris Phenol compounds such as (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, sulfur such as dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate And phosphorous compounds such as trisnonylphenyl phosphite and distearyl pentaerythritol diphosphite.

  Stabilizers include benzotriazole compounds including 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, and benzophenone compounds such as 2,4-dihydroxybenzophenone, mono- or distearyl phosphate, trimethyl phosphate And phosphoric acid esters.

  These various additives may have a synergistic effect by combining two or more kinds, and may be used in combination.

  For example, the additive exemplified as the antioxidant may act as a stabilizer or an ultraviolet absorber. Some of those exemplified as stabilizers also have an antioxidant action and an ultraviolet absorption action. In other words, the classification is for convenience and does not limit the action.

  Examples of the ultraviolet absorber include 2-hydroxy-4-n-dodecyloxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, and bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane. Benzophenone-based ultraviolet absorbers typified by, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) Benzotriazole, 2- (2′-hydroxy-3 ′, 5′-bis (α, α′-dimethylbenzyl) phenylbenzotriazole, 2,2′methylenebis [4- (1,1,3,3-tetramethyl) Butyl) -6- (2H-benzotriazol-2-yl) phenol], methyl-3- [3-tert-butyl-5 The benzotriazole type ultraviolet absorber represented by the condensate with-(2H-benzotriazol-2-yl) -4-hydroxyphenylpropionate-polyethylene glycol can be mentioned.

  Also, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6- Tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetra Carboxylate, poly {[6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethylpiperidyl ) Imino] hexamethylene [(2,2,6,6-tetramethylpiperidyl) imino]}, polymethylpropyl 3-oxy- [4- (2,2,6,6-tetramethyl) piperidinyl] siloxane. It can also include hindered amine light stabilizers represented by, such light stabilizers in combination with the ultraviolet absorber and various antioxidants, exhibit better performance in terms of weather resistance.

  Flame retardants are halogen-based, phosphoric ester-based, metal salt-based, red phosphorus, silicon-based, metal hydrate-based, and the like, and also include anti-dripping agents. Examples of the colorant include organic dyes, organic pigments, and inorganic pigments. Other examples include fluorescent brighteners, phosphorescent pigments, fluorescent dyes, flow modifiers, inorganic and organic antibacterial agents, photocatalytic antifouling agents, impact modifiers such as graft rubber, infrared absorbers, and photochromic agents. be able to.

  In the thermoplastic resin composition of the present invention, these blending components are preferably dispersed uniformly, and any blending method can be used. A typical example is a method of melt-kneading at a temperature of 200 to 350 ° C. using a known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll. Each component may be mixed in advance and then melt kneaded. In addition, although it is better that the water | moisture content adhering to each component is less and it is desirable to dry beforehand, not all the components need to be dried.

  As an example of a preferable production method of the thermoplastic resin composition of the present invention, a twin screw extruder having a cylinder temperature of 230 to 300 ° C. is used, and the raw materials blended with (A) to (D) and other additives are extruded. And a method of utilizing shear field-dependent spinodal decomposition, and as a method of realizing compatibilization during melt-kneading, a polybutylene terephthalate resin and Examples thereof include a method in which a polycarbonate resin is melt-kneaded under a high shear stress in a kneading zone of a twin-screw extruder.

  The vehicle parts of the present invention are generally molded by a known thermoplastic resin molding method such as injection molding, extrusion molding, blow molding, transfer molding, vacuum molding, etc., and among them, injection molding is preferable. In the case of producing by injection molding, it is preferable that the cylinder temperature is about 20 ° C. to 50 ° C. higher than the melting point of the resin composition, and the mold temperature is 60 to 120 ° C.

  The thermoplastic resin composition of the present invention is excellent in weather resistance and excellent in impact resistance, chemical resistance and mechanical properties, and is designed for vehicles such as door handles, pillars, side moldings, side protectors, and automobile interior switches. It can be suitably used as a component. In particular, it is preferably used as an exterior part for a vehicle because it is excellent in weather resistance, impact resistance, chemical resistance, and physical properties in a well-balanced manner.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  The evaluation method of an Example and a comparative example is shown next.

(1) Confirmation of structural period or interparticle distance For a 3 mm thick square plate injection molded under the conditions of a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C., a 100 μm thick slice was cut out and stained with an iodine dyeing method, Observation was performed with a transmission electron microscope at a magnification of 100,000 times, and then measured by small-angle X-ray scattering. The X-ray generator is RU-200 manufactured by Rigaku Corporation, using CuKα rays as the radiation source, output 50 KV / 150 mA, slit diameter 0.5 mm, camera radius 405 mm, exposure time 120 minutes, scattered photograph with film Kodak DEF-5 Was taken. In small angle X-ray scattering, the structure period (Λm) was calculated from the wavelength (λ) and scattering angle (θm) by the following equation.
Λm = (λ / 2) / sin (θm / 2)

  The distance between particles in a dispersed structure was determined in the same manner. From the small-angle X-ray scattering, the structural period or interparticle distance at which the structure was observed was measured.

(2) Evaluation of weather resistance A 3 mm thick square plate injection molded under conditions of a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C. was treated with a sunshine weatherometer for 1000 hours and discolored from the initial color according to JIS Z8722. The degree ΔE was evaluated.

(3) Evaluation of impact resistance (Charpy impact strength) Charpy impact strength was measured in accordance with ISO179 for a test piece injection molded under conditions of a cylinder temperature of 260 ° C and a mold temperature of 80 ° C.

(4) Evaluation of chemical resistance A test piece injection-molded under the conditions of a cylinder temperature of 260 ° C and a mold temperature of 80 ° C was immersed in a diluent of 50 parts of wax remover for 72 hours, and bending strength was evaluated according to ISO 178.

(5) Evaluation of tensile strength and tensile elongation Tensile properties were evaluated in accordance with ISO527-1, 2 for test pieces injection molded under conditions of a cylinder temperature of 260 ° C and a mold temperature of 80 ° C.

(6) Evaluation of rigidity (flexural modulus)
Test specimens injection-molded under conditions of a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C. were evaluated for flexural modulus according to ISO178.

Examples 1-6
The following resins (A) to (D) and titanium oxide were blended in combinations shown in Table 1.
(A-1) Polybutylene terephthalate resin: “Toraycon 1200S” manufactured by Toray Industries, Inc., intrinsic viscosity 0.89 (hereinafter also referred to as PBT)
(B-1) Aromatic polycarbonate resin: “A2600” manufactured by Idemitsu Chemical Co., Ltd., number average molecular weight 26000 (hereinafter also referred to as PC)
(C-1) Rubber polymer: “M-511” manufactured by Kaneka Chemical Co., Ltd., average particle size = 0.66 μm
(D-1) Titanium oxide: “CR-63” manufactured by Ishihara Sangyo Co., Ltd., average particle size = 0.21 μm, produced by the chlorine method, alumina hydrate and silicic acid hydrate, two kinds of treating agents Rutile titanium oxide used as
(D-2) Titanium oxide: “CR-60” manufactured by Ishihara Sangyo Co., Ltd., average particle diameter = 0.21 μm, manufactured by the chlorine method, rutile titanium oxide using only alumina hydrate as a treating agent .
(D-3) Titanium oxide: “A-220” manufactured by Ishihara Sangyo Co., Ltd., average particle size = 0.16 μm, manufactured by the sulfuric acid method, anatase type titanium oxide using only alumina hydrate as a treating agent .
(D-4) Titanium oxide: “CR-95” manufactured by Ishihara Sangyo Co., Ltd., average particle size = 0.28 μm, produced by the chlorine method, alumina hydrate and silicic acid hydrate, treatment agent Rutile titanium oxide used as
(E-1) Fine particle titanium oxide: “Titanium oxide P25” manufactured by Nippon Aerosil Co., Ltd. average particle diameter = 0.02 μm

(A) (B) (C) (D) Components and all other additives were supplied from the original storage part of the twin screw extruder and melt kneaded in a twin screw extruder with a screw diameter of 57 mmφ set at a cylinder temperature of 250 ° C. Went. In a twin-screw extruder, the polybutylene terephthalate resin and the polycarbonate resin are made compatible by melt-kneading under shear in the range of a shear rate of 7000 sec ⁻¹ , and then non-sheared when discharged from the die. By causing spinodal decomposition, a resin composition having a structural period of 0.1 μm was obtained. The strand discharged from the die was cooled in a cooling bath and then pelletized with a strand cutter. Each pellet obtained was dried in a hot air dryer at 130 ° C. for 3 hours or more, and then a test piece was prepared to confirm the continuous period of both phases, weather resistance, impact resistance, chemical resistance, tensile strength, tensile elongation. The rigidity was evaluated. The results are also shown in Table 1. Each of the obtained compositions was excellent in weather resistance, chemical resistance, impact resistance, tensile strength, tensile elongation, and flexural modulus.

Comparative Examples 1-8
As shown in Table 2, the composition of the resin composition was changed, and the components (A), (B), (C), and (D), as well as all other additives, were supplied from the original charging section and melt-kneaded. The discharged strand was cooled in a cooling bath and then pelletized with a strand cutter. For Comparative Examples 1 and 5 to 8, resin compositions having a structural period of 0.1 μm were obtained using the same method as in the Examples. Each of the obtained pellets was dried for 3 hours or longer with a hot air dryer at 130 ° C., and then molded using the method described in the evaluation method and subjected to various evaluations. The obtained composition was inferior in any of weather resistance, chemical resistance, impact resistance, tensile strength, tensile elongation, and flexural modulus.

Claims (3)

  In 100 parts by weight of the resin component consisting of 25 to 55% by weight of the polybutylene terephthalate resin (A), 40 to 70% by weight of the polycarbonate resin (B) and 0.5 to 20% by weight of the rubbery polymer (C), the average particle diameter 0.01 to 1.9 parts by weight of titanium oxide (D) having a 0.10 to 0.25 μm, and a polybutylene terephthalate resin (A) and a polycarbonate resin (B) have a structural period of 0.001 to 0.001. A thermoplastic resin composition characterized by forming a 1.0 μm double-phase continuous structure or a dispersed structure having a distance between particles of 0.001 to 1.0 μm.   2. The thermoplastic according to claim 1, wherein the titanium oxide (D) is a rutile crystalline form produced by a chlorine method, and has alumina hydrate and silicic acid hydrate on its surface. Resin composition.   A vehicle exterior part comprising the thermoplastic resin composition according to claim 1 or 2.