JP2000198836A - Resin composition for lamp extension and lamp extension made thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polybutylene terephthalate resin composition for lamp extension, directly applicable to a molded lamp extension by evaporation and giving a lamp extension having excellent mirror quality (image sharpness). SOLUTION: The objective composition is composed of a polybutylene terephthalate having a butylene terephthalate oligomer content of <=0.30 wt.%, volatile gas generation of <=10 ppm by the heat-treatment at 150 deg.C for 60 min and an intrinsic viscosity [η] of 0.7-1.2 calculated from the solution viscosity measured in o-chlorophenol at 25 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a molded article which is excellent in surface properties of a molded article obtained without the occurrence of mold contamination during continuous molding, can be directly vapor-deposited on the molded article surface, and has excellent mirror surface properties (image sharpness). Further, the present invention relates to a resin composition for a lamp extension, which does not lose its mirror surface property (image sharpness) even when subjected to a heat treatment, and to a lamp extension obtained by injection molding and directly depositing the same. Lamp extensions are used especially for motor vehicles.

[0002]

2. Description of the Related Art A lamp extension for a vehicle is a component that covers the periphery of a lamp reflector, and is decorated with plating, painting, or the like according to the design of the vehicle. In addition, since the lamp generates heat when it is turned on, there is a problem in the lamp extension to suppress such dimensional change due to the heat and to reduce volatiles / precipitates that deteriorate the surface appearance. Conventionally, in order to solve these problems, a method for reducing the moisture content of a polyamide resin to a certain value or less as described in JP-A-8-134205, JP-A-6-20
As described in 3613, a method using a polyethylene terephthalate / polybutylene terephthalate material has been proposed.

[0003] However, such a method is performed in a manufacturing process having a step of adjusting the surface properties with an undercoat agent or the like as a pre-process such as plating or painting, or a lamp extension of a type in which light is condensed by a conventional glass lens. Although a sufficient surface property can be obtained with the lamp extension provided, a sufficient surface appearance can be obtained in the process in which the lamp reflector has the function of condensing light and the previous step of adjusting the surface property with an undercoat agent is omitted. Did not.

[0004]

In order to solve these problems, a method has been proposed in which a polycarbonate resin is used for a lamp extension as described in JP-A-9-176472. However, the polycarbonate resin has a problem that deformation due to heat from the lamp occurs.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a resin composition for a lamp extension which is particularly excellent in the mirror surface (image sharpness) of the surface of the lamp extension when it is used as a lamp extension. Make it an issue.

[0006]

As a result of intensive studies, the inventors have found that volatiles / precipitates contained in polybutylene terephthalate (hereinafter sometimes abbreviated as PBT) are generated by heating, and the surface of the lamp extension Of the volatile gas generated when the oligomer in the PBT used in the manufacture of the lamp extension is not more than 0.30 wt% and heat-treated at 150 ° C. for 60 minutes. By controlling the amount to 10 ppm or less, it was found that a lamp extension having good specularity (map sharpness) could be obtained, and the present invention was reached.

That is, in the present invention, the amount of volatile gas generated when the butylene terephthalate oligomer is 0.30 wt% or less and the heat treatment is performed at 150 ° C. for 60 minutes is 10 ppm.
Hereinafter, a resin composition for lamp extension comprising polybutylene terephthalate having an intrinsic viscosity [η] of 0.7 to 1.2 calculated from a solution viscosity measured in orthochlorophenol at 25 ° C.

Hereinafter, the present invention will be described in more detail. In the present invention, polybutylene terephthalate is a polyester comprising terephthalic acid as a main acid component and 1,4-butanediol as a main glycol component.

Here, "main" means 80 mol% or more, preferably 90 mol% or more, based on all dicarboxylic acid components or all glycol components.

[0010] A copolymer component can be copolymerized with polybutylene terephthalate. When the copolymerization component is copolymerized, the proportion of the copolymerization component is 20 mol%, preferably 10 mol% or less, based on all dicarboxylic acid components or all glycol components.

Examples of the acid component which can be copolymerized include aromatic dicarboxylic acids other than terephthalic acid, for example, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylketonedicarboxylic acid, diphenylsulfonedicarboxylic acid. Acids and the like; aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and the like; alicyclic dicarboxylic acids such as cyclohexane dicarponic acid, tetralin dicarboxylic acid and decalin dicarboxylic acid.

[0012] Copolymerizable glycol components other than butanediol include ethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, tricyclodecane dimethylol, xylylene glycol, bisphenol A, bisphenol B, bishydroxyethoxy bisphenol. A and the like are exemplified.

In addition, a functional compound having three or more valences such that glycerin, trimethylolpropane, pentaerythritol,
Trimellitic acid, tricinic acid, pyromellitic acid and the like may be copolymerized.

In the present invention, the butylene terephthalate oligomer is obtained as a result of a thermal decomposition reaction of polybutylene terephthalate during polymerization or in a molten state, and refers to dimer to pentamer butylene terephthalate.

The amount of the butylene terephthalate oligomer in the polybutylene terephthalate is at most 0.30% by weight, preferably at most 0.20% by weight. When the amount of the oligomer is more than 0.30 wt%, the amount of the oligomer is increased, the mirror surface property (image sharpness) during heating is deteriorated, and the surface of the mold is contaminated during continuous molding, and the surface of the lamp extension molded product is contaminated. , Making direct vapor deposition impossible.

When polybutylene terephthalate is heat-treated at 150 ° C. for 60 minutes, the amount of volatile gas is 10 ppm.
Or less, and particularly preferably 5 ppm or less. If it exceeds 10 ppm, fogging occurs on the mold surface, and the specularity (image sharpness) is deteriorated.

The intrinsic viscosity of polybutylene terephthalate is from 0.7 to 1.2, preferably from 0.9 to 1.0. If the intrinsic viscosity is less than 0.7, the mechanical strength of the lamp extension is reduced, and the lamp extension may be cracked when mounted on an automobile or the like. On the other hand, when the intrinsic viscosity exceeds 1.2, the fluidity of PBT decreases, and the injection moldability of the lamp extension deteriorates.

Further, a filler may be added to the above-mentioned polyester for the purpose of reducing the dimensional change, to such an extent that the vapor deposition surface property is not impaired.

The resin composition for lamp extension of the present invention may be used by mixing the above-mentioned components in advance using a mixer such as a tumbler, a V-type blender, a Nauter mixer, a Banbury mixer, a kneading roll, and an extruder. May be added during the polymerization reaction.

As a method for reducing the amount of butylene terephthalate oligomer in polybutylene terephthalate, a method of immersing pellets in warm water can be exemplified. However, the method for reducing the amount of butylene terephthalate oligomer is not limited to the above method.

The amount of butylene terephthalate oligomer in the resin composition constituting the lamp extension of the present invention obtained by injection molding the above resin composition is 0.30 w
t% or less, preferably 0.20 wt% or less. When the amount of oligomer exceeds 0.30 wt%, the amount of precipitated oligomer increases, the mirror surface property (map sharpness) of the lamp extension during heating is deteriorated, and the surface of the mold is further contaminated, and the surface of the lamp extension molded product is contaminated. In some cases, making direct vapor deposition impossible.

In the present invention, the intrinsic viscosity of polybutylene terephthalate constituting the lamp extension is 0.1.
7 to 1.2. If it is 0.7 or less, the mechanical strength of the lamp extension is reduced, and the lamp extension may be cracked when mounted on an automobile or the like. Also,
If the intrinsic viscosity exceeds 1.2, the fluidity of PBT will decrease, and the injection moldability of the lamp extension will be poor.

As a method of obtaining the lamp extension, a method of performing injection molding and directly vapor-depositing on the lamp extension molded product is preferable. As the molding conditions, the resin temperature is preferably 245 ° C to 280 ° C. If the temperature is lower than this, the melt viscosity is high, and injection molding is difficult.If the temperature is higher than this, the degradation of polybutylene terephthalate is promoted, the amount of oligomer increases, and stains occur on the mold surface during continuous molding, It is not preferable because the surface of the lamp extension molded product is easily stained. In this way, it is possible to obtain a lamp extension in which a metal film layer is formed directly on the surface of the lamp extension molded product. The metal film layer is preferably formed in a gas phase. The lamp extension is preferably obtained by heat-aging a lamp extension molded product obtained by molding and then forming a metal film phase.

Also, a method of blending a polybutylene terephthalate resin composition in which an additive is mixed at a high concentration with a polybutylene terephthalate resin composition to which no additive is added, and subjecting the mixture to injection molding so as to have a predetermined additive concentration. It is preferable from the viewpoint of dispersibility of the additive and suppression of the generation of butylene terephthalate oligomer.

A method of directly supplying the measured components to the supply port of the molding machine, or supplying the separately measured components to the supply ports of a molding machine having two or more supply ports to perform injection molding. Is also a preferable processing method from the viewpoint of suppressing the generation of butylene terephthalate oligomer.

[0026]

Embodiments of the present invention will be described in detail below. The measurement and preparation of polybutylene terephthalate were performed by the following methods.

[Measurement of Amount of Oligomer] The amount of butylene terephthalate oligomer was determined by adding 5 mg of a sample (pellet and extension molded product) to chloroform (0.4 m
1) Dissolved in a mixed solution of hexafluoropropanol (0.4 ml) and measured by gel permeation chromatography. The gel permeation chromatography apparatus used was Waters 486 manufactured by Waters, and the column was TOS manufactured by Tosoh Corporation.
SK-GELG2000H8 was used.

The analysis conditions are as follows. 1) Solvent: chloroform 2) Flow rate: 1.2 ml / min 3) Measurement time: 40 min 4) Injection volume 20 μl 5) Absorbance: 254 nm

[Measurement of the amount of generated volatile gas] The amount of generated volatile gas was evaluated by measuring 3 g of a sample (one obtained by freeze-pulverizing a pellet and one obtained by freeze-pulverizing an extension molded product).
The measurement was performed by measuring the amount of volatile gas generated when heat treatment was performed at 0 ° C. for 60 minutes using gas chromatography. For gas chromatography, use headspace gas chromatography (HS-GC: G, manufactured by Shimadzu Corporation).
C-9A HSS-2A and CR-4A) were used.

The analysis conditions are as follows. 1) Column: silicon 0V-1701, Id 0.25 mm × 50 mm, df 0.3 μm 2) Carrier gas: He 1.5 kg / cm 2 G 3) Split ratio: 80 4) Septum purge flow rate: 1.5 ml / min 5) Column INI. Temp: 50 ° C. 6) Column INI. 7) Column P. Time: 2 min RATE: 10 ° C./min 8) Column FINE. Temp: 250 ° C. 9) Column FINE. Time: 10min

[Measurement of Intrinsic Viscosity] The intrinsic viscosity [η] of the polymer is a value calculated from the solution viscosity measured in orthochlorophenol at 25 ° C.

Reference Example 1 Preparation of Polybutylene Terephthalate The polybutylene terephthalate used in Example 1 was prepared by placing pellets of polybutylene terephthalate having an intrinsic viscosity of 0.13 and an oligomer amount of 0.35 wt% in warm water at 80 ° C. After stirring for a period of time, the pellet was taken out and dried at 130 ° C. for 5 hours to reduce the amount of butylene terephthalate oligomer.

[Reference Example 2] Preparation of polybutylene terephthalate The polybutylene terephthalate used in Example 2 was prepared by placing pellets of polybutylene terephthalate having an intrinsic viscosity of 0.82 and an oligomer amount of 0.38 wt% in warm water at 80 ° C for 1 hour. After stirring, the pellets were taken out and dried at 130 ° C. for 5 hours to reduce the amount of butylene terephthalate oligomer.

Examples 1 and 2 and Comparative Examples 1 and 2 A polybutylene terephthalate resin composition having the characteristics shown in Table 1 was subjected to injection molding at a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C. Mirror flat plate (60 × 40 × 2.5m)
m) was molded. After molding, vacuum evaporation machine (JEOL Ltd.
According to JEE-400), aluminum (purity: 9) was deposited under a vacuum condition of 6.0 × 10 ⁻⁴ Pa and a deposition current value of 22.0 A.
9.99%) was directly deposited on the surface of the mirror flat plate at a thickness of 1 μm, and the mirror surface (map sharpness) at this time and a temperature of 170 ° C. × 2
The specularity (image sharpness) after the heat treatment for 4 hours was visually evaluated.

The results are shown in Table 1 as Example 1 and Comparative Examples 1 and 2. In addition, a polybutylene terephthalate resin composition having the characteristics shown in Table 2 by an injection molding machine,
A lamp extension molded product was formed under the conditions of a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C. After molding, the degree of vacuum is measured by a vacuum deposition machine (JEE-400, JEOL Ltd.).
Aluminum (purity: 99.99%) was directly deposited in a thickness of 1 μm on the surface of the lamp extension molded product under the deposition conditions of 0 × 10 ⁻⁴ Pa and a deposition current value of 22.0 A, and the mirror surface property (image sharpness) ) Was visually evaluated. Table 2 shows these results as Example 2.

[0036]

[Table 1]

[0037]

[Table 2]

The method and evaluation criteria for the specularity (map sharpness) of the lamp extension are shown below. Molded products by vacuum evaporation machine (mirror flat plate and extension molded products)
The mirror surface (map sharpness) at this time, and the mirror surface (heat sharpness) after heating at a temperature of 170 ° C for 24 hours
Was evaluated according to the following criteria. However, the lamp extension was evaluated only at the time of vapor deposition. ：: There is no fogging on the vapor deposition surface and the mirror surface is provided. X: The vapor deposition surface is cloudy and lacks specularity.

From the results shown in Table 2, it was confirmed that there was no difference between the lamp extension and the deposited mirror flat plate. From the results in Table 1, as shown in the examples, the present invention having a small amount of butylene terephthalate oligomer and a small amount of volatile gas,
It was confirmed that the surface of the molded product was hardly stained during continuous molding, and that the surface could be directly vapor-deposited on the molded product, and that the surface was excellent in specularity (image sharpness), particularly, after heat treatment (image sharpness).

[0040]

According to the present invention, the lamp extension molded product surface is less likely to be stained during continuous molding, it is possible to directly vapor-deposit the lamp extension molded product, and the lamp extension is excellent in mirror finish (image sharpness). A resin composition and a lamp extension comprising the same can be provided.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kiyoshi Sugie 1-4-13 Onodai, Midori-ku, Chiba-shi, Chiba F-term in the Chiba Research Center (reference) 2H042 DA02 DA11 DB06 DC02 DE01 4F100 AB01B AB10B AK42A AL05A BA02 EH36A EH66B GB32 JA07A JK14 JM02B 4J029 AA03 AB07 AC01 AC02 AD01 AD10 AE01 BA05 CB06A

Claims (5)

[Claims] 1. An intrinsic viscosity calculated from a solution viscosity measured at 25 ° C. in orthochlorophenol, wherein the amount of volatile gas generated when the butylene terephthalate oligomer is 0.30 wt% or less, heat treatment at 150 ° C. for 60 minutes is 10 ppm or less. A resin composition for lamp extension comprising polybutylene terephthalate having [η] of 0.7 to 1.2. 2. A lamp extension molded product obtained by injection-molding the resin composition according to claim 1, wherein the content of the butylene terephthalate oligomer is 0.30% by weight or less.
A lamp extension molded product having an intrinsic viscosity [η] of 0.7 to 1.2 calculated from a solution viscosity measured in orthochlorophenol at 25 ° C. 3. A lamp extension obtained by directly forming a metal film layer on the surface of the lamp extension molded product according to claim 2. 4. The lamp extension according to claim 3, wherein the metal film layer is formed in a gas phase. 5. The lamp extension according to claim 3, wherein a metal film phase is formed after heat-aging the lamp extension molded product.