JP2006225439A - Polyester resin composition for light-reflecting molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin composition that gives a light-reflecting molded article having a very high surface gloss, emitting a small amount of nonvolatile components (gases), permitting direct formation of a light-reflecting metal layer without coating an undercoat or the like thereon and being excellent in heat resistance and adhesion to the metal layer, and exhibits good mold release when molding. <P>SOLUTION: The polyester resin composition for obtaining the light-reflecting molded article having the light-reflecting metal layer formed thereon comprises (A) 100 pts.mass of a polyester resin mainly composed of an alkylene terephthalate recurring unit and, incorporated therewith, (B) 5-80 pts.mass of an inorganic filler having an average particle size of at most 5 μm, and 0.1-5 pts.mass in total of a mold release agent comprising (C1) a fatty acid ester compound and (C2) a silicone compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin composition for obtaining a polyester resin light reflector. More specifically, since the surface gloss of the molded product is extremely high and the amount of gas generated from the molded product is small, it is possible to form a light-reflecting metal layer directly without undercoating the molded product. Not only has high specularity and high brightness, but also maintains surface appearance (heat resistance) when used at high temperatures, has low mold release resistance during molding, and has good moldability, as well as adhesion to the metal layer. The present invention also relates to a polyester resin for the purpose of forming a light reflecting metal layer by an excellent coating and / or dry plating method.

Light reflectors, particularly reflectors such as extensions around automobile lamps, require high brightness, smoothness, uniform reflectance, and high heat resistance for the directionality and reflectivity of the lamp light source. . For this reason, conventionally, a light reflector has a crystalline thermoplastic polyester resin, particularly a polybutylene terephthalate resin, which is excellent in mechanical properties, electrical properties, other physical and chemical properties, and has good processability. A resin composition in which various reinforcing materials are added and blended with a mixture of butylene terephthalate and other resins is used. After pre-treatment (undercoating) such as undercoating on the molded product, techniques such as vacuum deposition are used. By forming a light-reflecting metal layer, an intended light reflector is obtained (see Patent Document 1). However, undercoating and other undercoating results in a significant cost increase, and it is desired to obtain a light reflector having a high luminance feeling without undercoating. In order for a reflector with a light reflection layer on one surface of the molded product without undercoating to have high brightness and uniform reflectance, the resin molded product itself has good surface smoothness and high gloss. It needs to have a sense of sexuality and brightness. In addition, the heat resistance of the resin is also a serious problem due to its application specifications. However, since high brightness is required, the surface of the molding die must be remarkably polished, and the mold separation at the time of taking out the molded product at the time of molding becomes worse and the molding cycle is lowered. Therefore, in order not to lower the moldability, it is necessary to improve both the mold release property and maintain the surface luminance.
JP-A-6-203613

In general, polybutylene terephthalate resin is rapidly solidified in a mold due to its high crystallization speed, and it is difficult to obtain good mirror transferability. Further, when an inorganic filler such as talc or mica is added to impart heat resistance, the relief of these fillers becomes remarkable.
Therefore, as a material method for obtaining molded products with high gloss and good surface properties, an amorphous polymer is added to polybutylene terephthalate resin, and the crystallization speed of the material is lowered to transfer the mold. And a method of suppressing the embossing of the filler is used. (See Patent Document 2). Further, as a technique on the molding surface, a method of improving fluidity by raising the resin temperature (see Patent Document 3), a method of raising mold temperature and delaying the solidification rate (see Patent Document 4). ) Etc. are generally used. Although the appearance of the molded product is improved by these methods, an increase in the resin temperature and mold temperature causes the generation of volatile matter during molding, and the appearance of cloudy (haze) appearance on the molded product surface due to the generation of volatile matter. Therefore, it is impossible to obtain a good molded product continuously, and new measures such as polishing and wiping the mold are required.
Japanese Patent Laid-Open No. 11-293099 JP 2002-88235 A JP 2004-240292 A

In addition, when the amorphous polymer itself has low heat resistance, the surface property caused by the amorphous polymer under high temperature use can be obtained. The brightness feeling is lowered, and the heat resistance level of the light reflector is lowered. In addition, an amorphous polymer having a high glass transition temperature generally has poor compatibility with a polybutylene terephthalate resin, and good surface properties cannot be obtained.
On the other hand, the use of polyglycerin stearic acid as a specific release agent has been proposed, but due to its high release resistance, there is a problem that a good molded product cannot be obtained due to deformation of the molded product at the time of demolding. It was. As described above, even when a reflective metal layer is directly deposited on a resin molded product without undercoating, it has good brightness, high reflectivity and good metal adhesion, and maintains these characteristics even under high temperature use. It has been desired to develop a polyester resin composition for obtaining a molded product that can be used for a light reflector having heat resistance.

  According to the present invention, the surface gloss of the molded product is very high and the amount of non-volatile components (gas) generated is small, and it is possible to directly form the light reflecting metal layer without undercoating the molded product. . Another object of the present invention is to provide a polyester resin composition that is capable of obtaining a light-reflecting molded article that is excellent in heat resistance and adhesion to a metal layer, and that has good mold release during molding.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above-mentioned problems.
That is, the present invention
(1) A polyester resin composition for obtaining a light-reflecting molded product in which a light-reflecting metal layer is formed on the molded product, wherein the composition is (A) 100 parts by mass of a polyester resin mainly composed of alkylene terephthalate. On the other hand, (B) 5 to 80 parts by mass of an inorganic filler having an average particle size of 5 μm or less, (C) 0.1 to 5 parts by mass of a release agent composed of a fatty acid ester compound and a silicone compound are included. Polyester resin composition for light reflection molding,
(2) The polyester resin composition for light-reflective molded products according to (1), wherein the release resistance value of the cylindrical molded product at a mold surface temperature of 50 to 90 ° C. during injection molding is 120 N or less,
(3) (B) The polyester resin composition for light reflection molded articles according to (1) to (3), wherein the inorganic filler having an average particle size of 5 μm or less is barium sulfate,
(4) A molded body in which a light reflecting metal layer is formed on at least a part of the surface of a molded product obtained by molding the resin composition of (1) to (3).

  The light reflection molded product obtained from the polyester resin composition of the present invention has extremely high surface brightness and excellent heat resistance and moldability. In addition, since it is possible to form a light-reflecting metal layer directly on the surface of the molded product without undercoating the molded product, for example, in the manufacture of headlamp extensions and lighting components, there is an environmental burden. It is small, has good working efficiency, and is excellent in terms of cost.

Hereafter, the structural component of the resin composition used for this invention is demonstrated in detail.
(A) The polyester resin mainly comprising alkylene terephthalate as a repeating unit in the present invention is a polyester resin having 70% by mole or more of alkylene terephthalate as a repeating unit, and a dicarboxylic acid component such as terephthalic acid and / or an ester derivative thereof, For example, linear or branched alkylene diols having 2 to 12 carbon atoms, such as ethylene glycol, 1,2-propanediol or 1,3-propanediol, 1,4-butanediol, 1,5-pentane It can be obtained by polymerizing diol components such as diol, neopentyl glycol, 1,6-hexanediol and 1,12-dodecanediol. The diol component is preferably a linear or branched alkylene diol having 2 to 6 carbon atoms. Particularly preferred are linear diols containing 2 to 4 carbon atoms.

  (A) The polyester resin mainly comprising alkylene terephthalate as a repeating unit is mainly composed of polybutylene terephthalate, a mixture of polybutylene terephthalate and polyethylene terephthalate, a copolymer polyester mainly comprising alkylene terephthalate units, and polybutylene terephthalate and alkylene terephthalate units. A mixture with a copolymerized polyester as a component is preferred. In particular, in order to satisfy the brightness and heat resistance of the surface of the light reflection molded article obtained from the polyester resin composition of the present invention, it is preferable that 65 to 100 mol% of the polyester resin component is a butylene terephthalate unit.

  Examples of the dicarboxylic acid as a copolymerization component of the copolymerized polyester include linear or branched aliphatic dicarboxylic acids, particularly those having 2 to 40, preferably 4 to 10 carbon atoms, such as oxalic acid and malonic acid. , Succinic acid, dodecyl succinic acid, octadecyl succinic acid, pimelic acid, adipic acid, trimethyladipic acid, sebacic acid, azelaic acid and dimer acid (dimerized products of unsaturated fatty acids having 10 to 20 carbon atoms such as oleic acid) A cycloaliphatic dicarboxylic acid having 6 to 10 carbon atoms, such as 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3- and 1,4-cyclohexanedicarboxylic acid, 1,3; -And 1,4-methylcyclohexanedicarboxylic acid and 4,4'-dicyclohexyldicarboxylic acid Or aromatic dicarboxylic acids having for example 8 to 14 carbon atoms, such as isophthalic acid, phthalic acid, 1,3-, 1,4-, 2,6- or 2,7-naphthalenedicarboxylic acid, 4,4 '-Biphenyl dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 1,1,3-trimethyl-5-carboxyl-3- (p-carboxyphenyl) indane, 4,4'-diphenyl ether dicarboxylic acid and 4,4 Examples include '-diphenylmethanedicarboxylic acid.

Examples of the diol as a copolymerization component of the copolymer polyester include linear or branched aliphatic diols (excluding 1,4-butanediol), alicyclic diols such as 1,3-dihydroxycyclohexane, 1, 4-dihydroxycyclohexane and aromatic diols such as hydroquinone and resorcinol and in particular:

(Wherein the OH group is in the m-position and in particular the p-position, and R ′ and R ″ are alkyl groups of 1 to 6 carbon atoms, halogen atoms such as chlorine or bromine atoms, and in particular hydrogen atoms. Bisphenol represented by A may be a direct bond or O, S, SO ₂ , —C _p H _2p —, where _p represents 1-4 and in particular —CH ₂ — or —C (CH ₃ ) ₂ —. Examples of such bisphenols are: bis (p-hydroxyphenyl) ether or -thioether, bis (p-hydroxyphenyl) sulfone, bis (p-hydroxyphenyl) methane, 1,2-bis (p-hydroxyphenyl) ethane 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1- or 2,2-bis (p-hydroxyphenyl) butane, 2,2-bis (3,5-dibromo-4- Hydroxyphenyl) propane (also referred to as terebromobisphenol A) and in particular 2,2-bis (p-hydroxyphenyl) propane (also referred to as bisphenol A).

  Further suitable diols are, for example, 1,1-bis (p-hydroxyphenyl) cyclohexane (also referred to as bisphenol C); β-hydroxyalkylated, in particular β-hydroxyethylated bisphenols, such as 2,2-bis [4- (Β-hydroxyethoxy) phenyl] propane, 1,4-bis (hydroxymethyl) cyclohexane; aromatic diols, aliphatic diols such as p-dihydroxymethylbenzene, 2,5-dichloro-p-dihydroxy-methylbenzene; poly Alkylene glycols such as diethylene glycol, triethylene glycol, polyethylene glycol and N, N′-heterocyclic containing diols such as N, N ′-(2-hydroxyethyl) -5,5-dimethylhydantoin, NN ′-(2 -Hydroxyethyl) ben Imidazolone and N, N '- (2-hydroxyethyl) -4,5,6,7-Gro mode benzimidazolone.

(A) In the polyester resin mainly having alkylene terephthalate as a repeating unit,
A polyester other than a polyester having an alkylene terephthalate unit as a main component or a copolyester other than a copolymer polyester having an alkylene terephthalate unit as a main component may be mixed, but the repetition of alkylene terephthalate contained in (A) A unit is 70 mol% or more of a polyester resin component. Particularly preferably, the repeating unit of butylene terephthalate contained in (A) is 70 mol% or more of the polyester resin component.

(A) The polyester resin mainly containing alkylene terephthalate as a repeating unit may be branched by a trivalent to tetravalent alcohol or a 3 to 4 basic acid. Suitable branching agents are, for example, trimellitic acid, pyromellitic acid, 1,1,1-trimethylolpropane and pentaerythritol.
Copolyester is a copolymer component, in particular 2,2-bis [4- (β-hydroxyethoxy) phenyl] propane in an amount of 0.5 to 10 mol%, in particular 2 to 10 mol%, relative to the diol component. Those containing these groups are preferred.

The inorganic filler (B) used in the present invention has an average particle size of 5 μm or less, more preferably 2 μm or less, and still more preferably 1 μm or less. By adding an inorganic filler having an average particle size of 5 μm or less, a molded product having heat resistance due to the inorganic filler and having a good surface appearance can be obtained. In particular, when an inorganic filler having an average particle size of 1 μm or less is used, a molded article having extremely good surface gloss can be obtained.
On the other hand, when the average particle size of the inorganic filler is larger than 5 μm, the inorganic filler is lifted on the surface of the molded product, and a molded product having a good appearance cannot be obtained.

  As long as the (B) inorganic filler in the present invention satisfies the above particle diameter, it may be any shape such as granular, plate-like or wedge-like. Suitable fillers such as quartz, kaolin, talc, mica, graphite, wollastonite, glass beads, calcium carbonate, calcium sulfate, barium carbonate and barium sulfate, magnesium carbonate and magnesium sulfate and zinc sulfide, zinc oxide and magnesium titanate are suitable. In particular, barium sulfate having a fine and uniform particle size and good thermal stability is preferable.

  The blending amount of the inorganic filler (B) in the present invention is 5 to 80 parts by mass, preferably 5 to 50 parts by mass, based on 100 parts by mass of the polyester resin (A) mainly composed of alkylene terephthalate. If it exceeds 80 parts by mass, the molded product becomes brittle, which is not preferable. Moreover, in order to improve the heat resistance of a molded article, it is necessary to mix | blend 5 mass parts or more.

In the present invention, the releasability of the molded product from the mold at the time of molding is improved, and an excellent appearance of the molded product is obtained. Further, a light-reflecting metal layer is directly formed on the molded product without undercoating or other undercoating. However, in order to ensure sufficient adhesiveness, a fatty acid ester compound and a silicone compound are used in combination in the release agent (C). The release agent of the fatty acid ester compound and the silicone compound acts synergistically, so that the appearance of the surface of the molded product is not deteriorated due to the bleeding out of the release agent, so that the release property from the mold is excellent. Characteristics are obtained.
Examples of the fatty acid ester compounds include fatty acid esters, glycerin fatty acid esters, sorbitan fatty acid esters, montanic acid esters, and montanic acid partially saponified products. Among these, fatty acid ester compounds having 22 or more carbon atoms are particularly preferable. Particularly preferred are montanic acid esters and partially saponified products of glycerin esters of montanic acid.
Examples of the silicone compound include dimethyl silicone oil, methylphenyl silicone oil, various modified silicone oils, and the like.
It is also possible to use a different type of release agent in combination with the release agent consisting of the above two types of fatty acid ester compound and silicone compound.

The compounding quantity of the (C) mold release agent in this invention is 0.1-5.0 mass parts with respect to 100 mass parts of (A) the polyester resin which has an alkylene terephthalate as a repeating unit mainly. If the blending amount exceeds the above range, depending on the use temperature, a cloudy appearance defect or bleeding may become apparent, which is not preferable. Conversely, if the blending amount is small, effective mold release cannot be obtained.
Particularly preferable blending amounts are (A) 0.1 to 1% by mass of the fatty acid ester compound and 0.1 to 1% by mass of the silicone compound with respect to 100 parts by mass of the polyester resin mainly composed of alkylene terephthalate. By using a fatty acid ester compound and a silicone compound in combination, a polyester resin composition that does not deteriorate the appearance of the surface of the molded article due to bleeding out of the mold release agent and has little mold release resistance at the time of injection molding. can get.

Further, in the present invention, the thermal stability at the time of molding of the resin composition constituting the light reflector is improved, and particularly the gas generated in the molded product obtained from the resin composition even when continuously molded, the low molecular component Further, an antioxidant can be added in order to suppress a decrease in the appearance and brightness due to the influence of the exudate and the like.
The antioxidant that can be used in the present invention is preferably composed of one or a combination of two or more selected from hindered phenols, thioethers, and organic phosphites. It is effective for improving the heat stability of the melt at the time and in the molding machine, and is useful for continuously producing molded products with good appearance and surface smoothness with little occurrence of surface haze due to volatilization. In addition, when the light reflector is placed under a high temperature condition, it is particularly useful for suppressing volatilization generated from the resin and generation of decomposition products and maintaining good appearance and surface smoothness.

  Specific examples of the antioxidant used here include tetrakis {methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate} methane, triethylene glycol- as hindered phenols. Bis {3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate}, 1,6-hexanediol-bis {3- (3,5-di-t-butyl-4-hydroxyphenyl) Thioethers include tetrakis {methylene-3- (dodecylthio) propionate} methane, dimyristyl thiodipropionate, didodecylthiodipropionate, and the organic phosphites include bis (2, 6-di-t-4methylphenyl) pentaerythritol diphosphite, bis (2 4-di-t-butylphenyl) pentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene phosphite, tris (2,4-di-t-butylphenyl) ) There are phosphites. Particularly, hindered phenols and thioethers, hindered phenols and organic phosphites, and a combination of these three antioxidants are effective.

In addition, metal phosphates are also suitable as an alternative to organic phosphites antioxidants. Specific examples include monohydrates of primary calcium phosphate and primary sodium phosphate.
The compounding quantity of antioxidant is 0-3.0 mass parts with respect to 100 mass parts of (A) polyester resin which has an alkylene terephthalate as a repeating unit mainly. If the blending amount exceeds this, a cloudy appearance defect or bleeding may be manifested, which is not preferable.

  Furthermore, the polyester resin composition of the present invention can be blended with known substances that are generally added to thermoplastic resins and the like in order to impart desired properties according to the purpose. For example, any of antistatic agents, colorants such as dyes and pigments, and the like can be blended.

  The polyester resin composition of the present invention is easily prepared by equipment and methods generally used as conventional resin composition preparation methods. For example, (1) a predetermined amount of components constituting the composition of the present invention are mixed at once and melt-kneaded with a uniaxial or biaxial extruder to obtain pellets of the desired composition. (2) A uniaxial or biaxial extruder having two or more raw material input ports. After the resin, stabilizer, pigment component, etc. are injected from the first input port and melt kneaded, the second raw material input port More inorganic filler is added and melt-kneaded to obtain pellets of the desired composition.

  As a molding method for filling a resin with a mold, there are an injection molding method, an injection compression molding method and the like, and an injection molding method is general. The mold is preferably mirror-finished by chrome plating or the like.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, the measuring method of the material used in the Example and an evaluation item is as follows.
In the examples, parts and% are based on mass unless otherwise specified.

<Materials used>
(A1) PBT: polybutylene terephthalate resin having ηsp / C (reduced viscosity) of 1.23 dl / g and a terminal carboxyl group amount of 30 eq / kg.
(A2) PET: ηsp / C (reduced viscosity) 0.62 dl / g, polyethylene terephthalate resin having a terminal carboxyl group amount of 30 eq / kg (B1) Zinc oxide: 1 type zinc oxide (manufactured by Shodo Chemical Industry Co., Ltd.), Average particle size 0.6μm
(B2) Barium sulfate: B-55 (manufactured by Sakai Chemical Industry Co., Ltd.), average particle size 0.6 μm
(B3) Talc: Micron White 5000A (manufactured by Hayashi Kasei Co., Ltd.), average particle size 8 μm
(C1) Release agent 1: Fatty acid ester compound (Montanic acid ester, Licolub WE-40, manufactured by Clariant Japan Co., Ltd.)
(C2) Release agent 2: Silicone compound (polyether-modified silicone, Paintad 54, manufactured by Dow Corning Asia Co., Ltd.)
(C3) Mold release agent 3: (polyglycerol stearic acid ester, Riquemar AF-70, manufactured by Riken Vitamin Co., Ltd.)

Hereinafter, the measurement evaluation method will be described.
(1) Production of flat plate test piece for evaluation A flat plate test piece of 100 × 100 × 2 mm (thickness) was used for the appearance evaluation.
The flat plate test piece was obtained by injection molding under the following molding conditions.
Injection molding machine: IS-80 manufactured by Toshiba Machine Co., Ltd.
Cylinder 1-4 zone temperature: 240-250-250-250 ° C
Injection speed: 2.0 m / min Holding pressure: 400 kgf / cm ²
Mold temperature: 60 ℃

(2) Appearance evaluation of light-reflecting surface The flat plate test piece obtained by injection molding was decompressed to 1.0 × 10 ⁻² Pa using a vapor deposition device, and the vapor deposition rate was 1.0 nm / sec. The aluminum was evaporated to a film thickness of 100 nm. The appearance of the light-reflecting surface of the vapor-deposited flat test piece was visually observed and given the following score.
1: A high brightness feeling and a fluorescent lamp clearly appear without distortion.
2; It has a high brightness feeling, and the fluorescent lamp appears without distortion, but there is some cloudiness.
3; Although the fluorescent lamp is projected without distortion, it is somewhat blurred and cloudy.
4; The surface is not uniform, and the fluorescent lamp is slightly distorted and cloudy.
5; The surface is rough, and the fluorescent light is waved and appears white.
Further, the vapor-deposited flat test piece light reflector was left in a heating oven at 160 ° C. for 24 hours and then taken out. Similarly, the appearance of the light reflecting surface was visually observed and scored in the same manner.

(3) Cross-cut peel evaluation The adhesion between the aluminum film formed on the flat test piece by vapor deposition and the flat test piece was evaluated by cross-cut peel. Using a flat plate (100 mm × 100 mm × 2 mm thickness) molded under the above conditions, a room temperature flat molded product deposited by the method described above is left in a constant temperature and humidity chamber at 23 ° C. and a relative humidity of 40% for 24 hours. After that, a cross-cut peel test with 100 cross-cuts at intervals of 1 mm was performed using Nichiban Co., Ltd. adhesive tape: cello tape (registered trademark). The evaluation was performed by performing five cross-cut peel tests on each example and comparative example, and expressing the remaining number of cross-cuts remaining on the surface of the test plate as a percentage.

(4) Release resistance value measurement A cylindrical molded product having an outer diameter of 150 mm, an inner diameter of 145 mm, a height of 60 mm, and a taper of 1 ° provided with a pressure sensor for detecting a resistance force when the molded product is ejected from the mold with an ejector pin. A mold was used, the mold surface temperature was adjusted to 50 to 90 ° C., and the mold release resistance value at the time of injection molding was measured. In the evaluation, when the mold release resistance was high and the molded product was deformed or broken by the ejector pin, measurement was impossible (indicated by x in Table 1).
Injection molding machine: IS-100, manufactured by Toshiba Machine Co., Ltd.
Cylinder 1-4 zone temperature (° C): 240-250-250-250
Injection pressure: 60MPa
Injection time: 16 seconds Cooling time: 35 seconds

(5) Deflection temperature under load Measured according to ISO75-1,2. (Flatwise, using a measurement weight with a fiber stress of 0.45 MPa)
(6) Measurement of average particle diameter of inorganic filler After centering the flat plate test piece obtained by injection molding with a microtome, applying carbon deposition, field emission scanning electron microscope (S4500, manufactured by Hitachi, Ltd.) ) At an accelerating voltage of 20 KV and a magnification of 500 to 5000 times, and taking a picture. Next, in the obtained photograph, the equivalent circle diameter (the diameter of a circle having an area equal to the area in the photograph of the particle) was measured for 100 particles, and the average particle diameter was calculated.

(Examples 1-3, Comparative Examples 1-5)
The material was blended so as to have the blending amounts shown in Table 1, and the twin-screw extruder (Ikegai Iron Works Co., Ltd., in which the temperature of each part of the nozzle from the cylinder was sequentially set to 240-250-250-250 ° C., Polyester resin composition pellets were obtained by melt-kneading with PCM30). Next, the obtained pellets were dried at 140 ° C. for 4 hours, and then injection molded using a chromium-plated mirror mold having a mold surface temperature of 60 ° C. using an injection molding machine under the above molding conditions. A flat test plate for evaluation was obtained. The evaluation results are shown in Table 1.

  As is clear from the examples, the light reflector obtained from the polyester resin composition of the present invention is excellent in surface brightness and heat resistance, and has low mold release resistance and excellent moldability.

  The molded product obtained from the polyester resin composition for light reflecting molded product of the present invention is excellent in heat resistance and dimensional stability during molding, and has extremely high surface gloss, without undercoating the molded product. It is possible to form a direct light reflecting metal layer. Moreover, there is little release resistance from the mold at the time of injection molding, and the productivity is excellent. Therefore, in the production of the polyester resin composition for light reflection molded products of the present invention, such as headlamp extensions and lighting parts, it is excellent in environmental protection, work efficiency, and cost, and contributes greatly to the industry. is there.

Claims (4)

  A polyester resin composition for obtaining a light-reflecting molded article having a light-reflecting metal layer formed on a molded article, wherein the composition is (A) 100 parts by mass of a polyester resin mainly comprising alkylene terephthalate, (B) 5 to 80 parts by mass of an inorganic filler having an average particle size of 5 μm or less, and (C) 0.1 to 5 parts by mass of a release agent composed of a fatty acid ester compound and a silicone compound. Polyester resin composition for molded articles.   2. The polyester resin composition for light-reflective molded products according to claim 1, wherein a release resistance value of the cylindrical molded product at a mold surface temperature of 50 to 90 ° C. during injection molding is 120 N or less.   (B) The polyester resin composition for light reflection molded products according to any one of claims 1 to 3, wherein the inorganic filler having an average particle size of 5 µm or less is barium sulfate.   The molded object for light reflections obtained by shape | molding the polyester resin composition in any one of Claims 1-4.