JP2003268216A - Polyester resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin composition which gives a heat-resistant molded article (a light-reflecting body) which, even when a light-reflecting metallic layer is vapor-deposited thereon directly without forming thereon an undercoating layer, exhibits good brightness, high reflectance, and good adhesion to a metal and can retain these characteristics even under high-temperature use. <P>SOLUTION: This polyester resin composition, used for preparing a light- reflecting molded article by forming a light-reflecting metallic layer on a molded article obtained from the composition, is prepared by compounding (A) 100 pts.wt. polybutylene terephthalate resin with (B) 5-100 pts.wt. polyethylene terephthalate resin and (C) 1-100 pts.wt. polyalkylene naphthalate resin. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester resin composition used for a light reflection molded article. More specifically, since the surface gloss of the molded product is extremely high and the amount of gas generated is small, it is possible to form the light-reflecting metal layer directly without undercoating the molded product. A light-reflecting metal layer is formed by coating and / or dry plating, which not only has specularity and high brightness, but also maintains surface appearance (heat resistance) when used at high temperatures and has excellent adhesion to the metal layer. The present invention relates to a polyester resin composition intended to be formed. The light reflector, which is one application of the composition of the present invention, is suitably used for parts around lamps in the fields of automobiles, construction equipment and various industries. Particularly, it is suitably used for reflectors, extensions, etc., which are lamp peripheral parts for automobiles, which require high surface brightness, smoothness, and high light reflectance.

[0002]

2. Description of the Related Art Generally, a light reflector, particularly a reflector such as an extension around an automobile lamp, has a high sense of brightness, smoothness, a uniform reflectance and a high reflectance due to the directionality and reflectivity of the lamp light source. Heat resistance is required. Therefore, conventionally, a crystalline thermoplastic polyester resin having excellent mechanical properties, electrical properties, other physical / chemical properties, and good processability, particularly polybutylene terephthalate resin alone or polyethylene has been used for the reflector. Pre-treatment (undercoating) such as undercoat is used for the molded product, which is made of a mixture of terephthalate resin and various reinforcing agents.
After that, the desired light reflector was obtained by forming the light-reflecting metal layer by a method such as vacuum deposition.

However, since the undercoating of an undercoat or the like greatly increases the cost, it is desired to obtain a light reflector having a high brightness even without the undercoating. In order for the reflector having a light-reflecting layer to be provided on at least one surface of the molded product without an undercoat to have high brightness and uniform reflectance, the resin molded product itself has good surface smoothness, and It is necessary to have high gloss and brightness.

The heat resistance of the resin is also an important issue due to its application specifications. In general, a polybutylene terephthalate resin is solidified quickly in a mold due to its high crystallization rate, and it is difficult to obtain good mirror surface transferability. Further, when an inorganic filler such as talc or mica is added to impart heat resistance, the embossment of these fillers becomes remarkable.

Therefore, as a method in terms of materials in order to obtain a molded article having a high gloss feeling and good surface property, an amorphous polymer is added to polybutylene terephthalate resin to reduce the crystallization rate of the material and to reduce gold. A method of improving the mold transfer property and suppressing the protrusion of the filler is used. In addition, as a method for molding, a method of increasing the resin temperature to improve the fluidity, a method of increasing the mold temperature to delay the crystallization rate and improve the mold transfer property are generally used. Although the appearance of the molded product is improved by these methods, the rise in the resin temperature and the mold temperature makes the problem of the gas generated during molding remarkable, and causes a haze appearance defect on the surface of the molded product. However, it is not possible to continuously obtain good molded products, and it is necessary to take new measures such as polishing and wiping the mold. In addition, when an amorphous polymer is added, if the amorphous polymer itself has a low heat resistance, the amorphous polymer causes a decrease in surface properties and a sense of brightness due to the amorphous polymer, and heat resistance as a light reflector. It will lower the level.
Further, 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.

[0006]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, that is, even if a light-reflecting metal layer is directly vapor-deposited on a resin molded product without undercoating, a good sense of brightness, It is an object of the present invention to obtain a polyester resin composition having a high reflectance and good metal adhesion, and having heat resistance capable of maintaining these characteristics even under high temperature use, which is used for a light reflection molded article. .

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present inventors have earnestly studied, studied, and finally completed the present invention. That is, the present invention is a polyester resin composition used in a light-reflecting molded article in which a light-reflecting metal layer is formed on the molded article obtained from the polyester resin composition, wherein the composition is (A) polybutylene terephthalate. A polyester resin composition characterized by containing 5 to 100 parts by weight of (B) polyethylene terephthalate resin and 1 to 100 parts by weight of (C) polyalkylene naphthalate resin with respect to 100 parts by weight of resin. The polyester resin composition as described above, wherein the amount of terminal carboxyl groups of the (A) polybutylene terephthalate resin and the (B) polyethylene terephthalate resin is 70 meq / kg or less. (C) Among the diol components of the polyalkylene naphthalate resin, the polyester resin composition as described above, wherein 1,4-butanediol is 75% or more in terms of mole fraction based on the total diol components. The polyester resin composition as described above, wherein the compounding amount of the (C) polyalkylene naphthalate resin is 1 to 50 parts by weight. The polyester resin composition according to any one of 1 to 3, wherein the light-reflecting metal layer is formed by forming a metal film having a mirror gloss on the surface of the resin molded product by a dry plating method. The polyester resin composition according to any one of the above 1 to 4, wherein a metal film having a specular gloss is formed by forming a light-reflecting metal layer, particularly by a vapor deposition method. The polyester resin composition according to any one of 1 to 3, wherein the metal forming the light-reflecting metal layer is aluminum. The polyester resin composition according to any one of 1 to 3, wherein a light-reflecting metal layer is directly formed on at least a part of the molded product.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The constituent components of the resin composition used in the present invention will be sequentially described in detail below. The (A) polybutylene terephthalate resin in the present invention is, for example, polybutylene terephthalate obtained by polycondensing terephthalic acid or its ester-forming derivative with alkylene glycol having 4 carbon atoms or its ester-forming derivative. Polybutylene terephthalate also has 70
It may be a copolymer containing at least wt%. Monomers to be copolymerized include dibasic acid components other than terephthalic acid and its lower alcohol ester, such as isophthalic acid, naphthalene dicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, succinic acid, and other aliphatic and aromatic polycarboxylic acids. Basic acid or its ester-forming derivative, etc.
As a glycol component other than 4-butanediol, a normal alkylene glycol, for example, ethylene glycol,
Diethylene glycol, propylene glycol, trimethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, etc.
Lower alkylene glycol such as 3-octanediol,
Aromatic alcohols such as bisphenol A and 4,4'-dihydroxybiphenyl, alkylene oxide adducts such as bisphenol A ethylene oxide 2 mol adduct, bisphenol A propylene oxide 3 mol adduct, glycerin, pentaerythritol and other poly alcohols Examples thereof include a hydroxy compound or an ester-forming derivative thereof. In the present invention, any polybutylene terephthalate produced by polycondensation using the above compound as a monomer component may be used as the component (A) of the present invention, and may be used alone or in combination of two or more kinds. However, preferably polybutylene terephthalate homopolymer is used.

Branched polymers belonging to the copolymers can also be used. The term “polybutylene terephthalate branched polymer” as used herein is a polyester which is mainly formed of so-called polybutylene terephthalate or butylene terephthalate monomer and which is branched by adding a polyfunctional compound. As the polyfunctional compound that can be used here, trimesic acid, trimellitic acid, pyromellitic acid and their alcohol esters, glycerin, trimethylolethane, trimethylolpropane,
For example, pentaerythritol.

In the (A) polybutylene terephthalate resin and (B) polyethylene terephthalate resin of the present invention, the amount of terminal carboxyl groups is preferably 70 meq / kg or less. It is more preferably 40 meq / kg or less, particularly preferably 30 meq / kg or less. If the amount of terminal carboxyl groups is 70 meq / kg or less, the haze of the obtained molded product is significantly reduced, and therefore it is very preferable for this application. The amount of terminal carboxyl group is measured by dissolving a ground sample of polybutylene terephthalate or polyethylene terephthalate polycondensed from the above monomer in benzyl alcohol at 215 ° C for 10 minutes and titrating with 0.01N aqueous sodium hydroxide solution. Is prescribed.

The (B) polyethylene terephthalate resin in the resin composition of the present invention is added to and blended with the (A) polybutylene terephthalate resin to improve the surface smoothness and brightness of the resulting molded article and the light-reflecting metal layer. It is an essential component for improvement. Since polyethylene terephthalate has a lower crystallization rate than polybutylene terephthalate, the addition and blending of polyethylene terephthalate has the effect of improving mold transferability as a resin composition. It is also effective in suppressing the deterioration of the surface smoothness and the sense of brightness, deformation, etc. that occur when the light reflector is exposed to high temperatures such as light and heat. From the above two viewpoints, the polyethylene terephthalate resin is an essential component in the present invention in order to obtain a good light-reflecting appearance product. The amount of the (B) polyethylene terephthalate added is 1 to 100 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the component (A). If the amount is too small, good mold transfer properties cannot be obtained, so that the light reflector having good brightness and surface smoothness, which is the object of the present invention, cannot be obtained.
On the other hand, if it is too large, molding problems such as an increase in molding cycle and deterioration of releasability will occur, and a defective appearance due to the generated gas will occur, resulting in deterioration of brightness and surface smoothness, which is not preferable.

Further, the (C) polyalkylene naphthalate resin in the resin composition of the present invention is added and blended with the (A) polybutylene terephthalate resin, whereby the surface smoothness of the resulting molded article and the light-reflecting metal layer, It is an essential component as in (B) for improving the brightness and the like. Since polyalkylene naphthalate has a smaller crystallization rate and a smaller coefficient of linear expansion than polybutylene terephthalate, the addition of the polyalkylene naphthalate has the effect of improving the mold transferability of the resin composition. In addition, since the heat distortion temperature is higher than that of polybutylene terephthalate, it suppresses the deterioration of surface smoothness and brightness, deformation, etc. that occurs when a molded product with a light reflecting layer is exposed to high temperatures such as light and heat. It also has an effect on From the above two viewpoints, the polyalkylene naphthalate resin is an essential component in the present invention in order to obtain a good light-reflecting appearance product.

The (C) polyalkylene naphthalate resin used in the present invention is mainly obtained by polycondensation reaction of naphthalene acid or its ester-forming derivative with C2-8 alkylene glycol or its ester-forming derivative. The polymer may be a copolymer containing 70 wt% or more of polyalkylene naphthalate.

In the polyalkylene naphthalate resin (C) used in the present invention, the acid component monomers to be copolymerized include, in addition to naphthalene dicarboxylic acid, terephthalic acid, isophthalic acid, adipic acid, sebacic acid, trimellitic acid. Examples thereof include aliphatic and aromatic polybasic acids such as succinic acid and ester-forming derivatives thereof. Preferably,
Naphthalenedicarboxylic acid / terephthalic acid /
Isophthalic acid is mentioned, and it is particularly preferable to use only naphthalenedicarboxylic acid.

In the (C) polyalkylene naphthalate resin used in the present invention, as a diol component, an ordinary alkylene glycol, such as diethylene glycol,
Propylene glycol, 1,4-butanediol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, etc., lower alkylene glycols such as 1,3-octanediol, ethylene oxide 2 mol adduct of bisphenol A, propylene oxide of bisphenol A Examples thereof include alkylene oxide adduct alcohols such as 3 mol adducts, polyhydroxy compounds such as glycerin and pentaerythritol, and ester-forming derivatives thereof. Preferable examples of the diol component include ethylene glycol / propion glycol / 1,4-butanediol, and it is particularly preferable to use only 1,4-butanediol.

Further, in the present invention, the thermal stability of the resin composition constituting the light reflector at the time of molding is enhanced, and particularly gas, low molecular component, generated from the resin composition when continuously molded,
An antioxidant can be further added in order to suppress the deterioration of the appearance and the feeling of brightness due to the influence of the exudate or the like.

The antioxidant that can be used in the present invention preferably comprises one or a combination of two or more selected from hindered phenols, thioethers and organic phosphites. The addition is
It has the effect of improving the melting heat stability during extrusion and in the molding machine, and is useful for continuously obtaining molded products with good appearance and surface properties with little surface clouding due to gas adhesion.
When the light reflector is placed under high temperature conditions, it is also particularly useful for suppressing the generation of gas and decomposition products from the resin and maintaining good appearance and surface properties.

Specific examples of the antioxidants used here include tetrakis {methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate} methane and trihinder as hindered phenols. Ethylene glycol-bis {3- (3-t-butyl-5-methyl-4-
Hydroxyphenyl) propionate}, 1,6-hexanediol-bis {3- (3,5-di-t-butyl-4-)
Hydroxyphenyl) propionate}, etc., thioethers such as tetrakis {methylene-3- (dodecylthio) propionate} methane, dimyristylthiodipropionate, didodecylthiodipropionate, etc. (2,6 −
Di-t-4 methylphenyl) 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) phosphite and the like. Particularly, the combined use of hindered phenols and thioethers, hindered phenols and organic phosphites, and these three kinds of antioxidants are effective. Metal phosphates are also suitable as a substitute for the organic phosphite antioxidants, and specific examples thereof include monobasic calcium phosphate and monobasic sodium phosphate.
A hydrate is mentioned.

Further, in the present invention, fatty acid ester compounds represented by glycerin fatty acid esters and sorbitan fatty acid esters, and partially saponified products thereof, in order to enhance the releasability of the product during molding and improve the appearance of the molded product. It is possible to add one or more kinds of compounds selected from polyether compounds, fatty acid metal salts, trimellitic acid esters and pyromellitic acid esters, and terminal-modified siloxane.

The amount of these compounds added is 0 based on 100 parts by weight of polyalkylene terephthalate containing (A) and (B).
~ 2.0 parts by weight. If the amount added exceeds this range, haze and exudation may become apparent depending on the use temperature, which is not preferable.

In the present invention, in order to improve heat resistance and the like, an inorganic reinforcing agent can be added within a range not exceeding 10 parts by weight with respect to 100 parts by weight of the resin composition. Specific examples include glass fibers, carbon fibers, fibrous reinforcing agents such as potassium titanate, and inorganic fillers such as talc, wollastonite, silica, clay, calcium carbonate, and glass beads. It is possible to add one or more kinds to.

Further, in the composition of the present invention, a known substance generally added to a thermoplastic resin or the like can be added and used in combination in order to impart desired properties according to the purpose. For example, an antistatic agent, a release agent, a coloring agent such as a dye or a pigment, and the like can be added.

The composition of the present invention can be easily prepared by the equipment and method generally used as the conventional resin composition preparation method. For example, (1) a predetermined amount of components constituting the composition of the present invention are collectively mixed and melt-kneaded with a uniaxial or biaxial extruder to obtain pellets having a target composition. (2) A single-screw or twin-screw extruder with two or more raw material inlets,
After the resin, stabilizer, pigment component, etc. are charged from the first charging port and melt-kneaded, the inorganic filler is charged from the second raw material charging port and melt-kneaded to obtain pellets of the target composition. To be

As a method for molding the composition of the present invention into a molded article, there are an injection molding method, an injection compression molding method and the like, but the injection molding method is generally used.

Next, examples of the method for forming the light-reflecting metal layer on the molded body include a method of forming by sputtering and a method of depositing under vacuum.

As a method of providing a light-reflecting metal layer on the layer of the polyester resin composition obtained as described above, there are a coating method and a dry plating method. Specifically, the coating method includes a dipping method, a scroll method, An electrostatic coating method and the like can be mentioned, and as the dry plating method, a vacuum vapor deposition method, a vaporization method, a sputtering method and the like can be mentioned. In the present invention, the vacuum vapor deposition method is preferable.

In the present invention, as the metal constituting the light reflecting metal layer, gold, silver, copper, aluminum, tin, lead, zinc, platinum, titanium, manganese, chromium, iron, nickel,
Examples thereof include cobalt, silicon, germanium, gallium, molybdenum, and alloys containing 50% or more thereof. In the present invention, aluminum and aluminum alloys are particularly preferable.

[0028]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. The measuring methods of the evaluation items shown in the following examples are as follows. Parts and% in the examples are by weight.

Thermoplastic polyester resin for explaining the compounding agents used below: Polybutylene terephthalate resin (hereinafter referred to as PBT-1) η
_sp / c: 1.23, Terminal carboxyl group amount (CEG amount): 30meq / kg Polybutylene terephthalate resin (hereinafter referred to as PBT-2) η
_sp / c: 0.85, terminal carboxyl group amount (CEG amount): 80meq / kg polyethylene terephthalate resin (hereinafter referred to as PET) η _sp /
c: 0.62 Terminal carboxyl group amount (CEG amount): 35 meq / kg Polybutylene naphthalate resin (hereinafter referred to as PBN) η _sp / c:
0.88 Polyethylene naphthalate resin (hereinafter referred to as PEN) η _sp / c:
0.75 Inorganic Reinforcing Agent: Talc Particle Size: 3.7μm Modified Silicone and / or Fatty Acid Ester Compound
(Hereinafter referred to as Wax): Paint 54 manufactured by Dow Corning Co., Ltd.
Wax-1) Clariant Japan KK Hostalub WE 40 (hereinafter
(Wax-2)

(1) Regarding the evaluation of appearance, 100 mm × 100 mm
Molding was performed under the following molding conditions using a flat plate molded product having a thickness of 2 mm. Molding conditions: Molding machine: Toshiba IS-80 Cylinder temperature (℃): 250-265-265-265 Injection speed: 2.0m / min Holding pressure: 400 kg / cm ² Mold temperature: 80 ℃

(2) Vapor deposition: For vapor deposition of a flat plate molded product, a vapor deposition apparatus was used, the pressure inside the vapor deposition apparatus was reduced to 1.0 × 10 ⁻² Pa, and
Aluminum was evaporated at a rate of nm / sec to a film thickness of 100 nm. The appearance of the light-reflecting surface of the light-reflecting body was visually observed, and the following points were given. 1; It has a high sense of brightness and the fluorescent lamp is clearly reflected without distortion. 2; It has a high brightness and the fluorescent lamp appears without distortion, but there is some cloudiness due to gas. 3; Some cloudiness due to gas is seen, and although the fluorescent lamp appears without distortion, it is slightly blurred. 4; The surface is not uniform, and the fluorescent lamp appears distorted to some extent. There is also clouding due to gas. 5: The surface is rough, and the fluorescent lamp is reflected in a wavy image. Also,
It looks white due to gas. Further, the light reflector is
After being left to stand for 24 hours at ℃, the state of the light-reflecting appearance was visually observed in the same manner and scored in the same manner.

(3) Surface smoothness: Using a flat plate (100 mm × 100 mm × 2 mm thickness) molded under the conditions of the above (1), using a surface roughness meter (Surfcom 554A manufactured by Tokyo Seimitsu Co., Ltd.) Then, the ten-point average roughness (μm) and the maximum height (μm) were measured. (4) Deflection Temperature Under Load (HDT): ASTM D-648
Was measured according to (using a measuring weight that gives a fiber stress of 0.46 MPa).

(5) Cross-cut peeling evaluation: As a method for evaluating the adhesion between the aluminum film formed on the flat plate molded product by vapor deposition and the flat plate molded product, the flat plate (1
00mm × 100mm × 2mm thickness), the room temperature flat-plate molded product vapor-deposited by the above method was left for 24 to 48 hours in a constant temperature and humidity chamber at 23 ° C and a humidity of 40%, and then a Nichiban cellophane tape was used. Using them, a cross-cut peeling test with 100 cross-cuts at 1 mm intervals was performed. For the evaluation, a cross-cut peeling test was performed 5 times for each of the examples and comparative examples, and the remaining number of cross-cuts remaining on the surface of the test plate was expressed as a percentage for evaluation.

Examples 1 to 5 and Comparative Examples 1 to 3 PBT-1, PET and PBN were used, and the ratio of each component ratio of the inorganic reinforcing agent / releasing agent was changed as shown in Table 1 and the cylinder temperature was changed. The pellets were obtained by melt-kneading with a twin-screw extruder set to 255-270-270-265 ° C from the nozzle side. Next, after drying each of the obtained pellets at 140 ° C for 4 hours, use a molding machine with a cylinder temperature of 240 to 260 ° C and inject using a chrome-plated mold with a mold surface temperature of 90 ° C. Molded to obtain a test plate for evaluation.

Example 6 PBT-1 in Example 1 was replaced with PBT-2, and melt kneading and injection molding were carried out in the same manner as in Example 1 to obtain a test plate for evaluation.

Example 7 Melt kneading and injection molding were carried out in the same manner as in Example 1 except that PBN was changed to PEN to obtain a test plate for evaluation.

[0037]

[Table 1]

[0038]

As described above, the composition of the present invention having such a constitution has a very high brightness sensation, and the deterioration of the brightness sensation due to clouding is small even after continuous molding and exposure to a high temperature, and the adhesion to a metal is good. It has excellent heat resistance. In addition, the cost can be reduced compared to conventional products. Such a light reflector is suitable for use in reflectors and extensions of automobile lamps, which particularly require high reflectivity, and greatly contributes to the industrial world.

Continued front page    F-term (reference) 4F100 AB01A AB10A AK41B AL05B                       BA02 BA07 EH66A EH71A                       GB32 GB90 JJ03 JL11 JN06A                       YY00B                 4J002 CF062 CF071 CF083 CF093                       CF103 FD010 FD070 FD160                       GN00 GP00 GQ00                 4K029 AA11 BA03 BC07 BD09 CA01                       DB03

Claims (8)

[Claims] 1. A polyester resin composition for use in a light-reflecting molded article in which a light-reflecting metal layer is formed on the molded article obtained from the polyester resin composition, the composition comprising:
(A) With respect to 100 parts by weight of polybutylene terephthalate resin,
(B) Polyethylene terephthalate resin 5 to 100 parts by weight
(C) A polyester resin composition containing 1 to 100 parts by weight of a polyalkylene naphthalate resin. 2. A (A) polybutylene terephthalate resin
The polyester resin composition according to claim 1, wherein the amount of terminal carboxyl groups of the (B) polyethylene terephthalate resin is 70 meq / kg or less. 3. The polyester resin composition according to claim 1, wherein among the diol components of the polyalkylene naphthalate resin (C), 1,4-butanediol is 75% or more in terms of mole fraction with respect to the total diol components. . 4. The polyester resin composition according to claim 1, wherein the compounding amount of the (C) polyalkylene naphthalate resin is 1 to 50 parts by weight. 5. The polyester resin composition according to claim 1, wherein the light-reflecting metal layer is formed by forming a metal film having specular gloss on the surface of the resin molded product by a dry plating method. 6. A light-reflecting metal layer is formed by forming a metal film having specular gloss, especially by a vapor deposition method.
The polyester resin composition according to any one of 1. 7. The polyester resin composition according to claim 1, wherein the metal forming the light reflecting metal layer is aluminum. 8. The polyester resin composition according to claim 1, wherein a direct light-reflecting metal layer is formed on at least a part of the molded product.