JPH0253461B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filler-reinforced polyethylene terephthalate resin composition having excellent moldability and physical properties. More specifically: (A) 100 parts by weight of a polyester resin having an intrinsic viscosity of at least 0.4 and in which at least 80 mol% of the constituent units are ethylene terephthalate units; (B) 10 to 140 parts by weight of reinforcing or filling substances; (C) carboxyl. 0.05 to 20 parts by weight of sodium salt or potassium salt of a polymer containing groups (D) General formula R ₁ O (−R ₂ O) − _o R ₁ ′ (However, R ₁ and R ₁ ′ represent lower alkyl groups. ,
R ₂ represents an alkylene group having 2 to 4 carbon atoms.
Further, n is a number of 5 or more. ) Poly(oxyalkylene) compound represented by
0.1 to 10 parts by weight and (E) sterically hindered phenol and/or general formula (R ₃ C ₆ H ₄ O _{) x} P (OR ₄ ) _y (wherein R ₃ represents H or an alkyl group, x , y is 0 or an integer from 1 to 3 x+
Represents a number that satisfies y=3. ) Regarding a polyester resin composition composed of 0.01 to 1 part by weight of an organic phosphorus compound represented by 100
The present invention relates to a novel filler-reinforced polyethylene terephthalate resin composition that exhibits excellent moldability when molded at a low mold temperature of .degree. C. or lower and provides a molded article with improved mechanical strength. Polyethylene terephthalate (hereinafter referred to as PET) has excellent heat resistance, chemical resistance, mechanical properties, electrical properties, etc., and is used in many industrial products such as fibers and films. In particular, PEH reinforced with fillers such as glass fibers has been widely used in engineering plastics and the like in recent years because it has significantly improved thermal and mechanical properties. However, when filler-reinforced PET is used for injection molding applications, it is known that there are major drawbacks in terms of molding and physical properties due to the crystallization behavior of PET. In other words, since PET has a low crystallization rate at low temperatures, for example 130℃
When injection molding is performed at a mold temperature below, it is difficult to obtain a molded product with good crystallization, and only a molded product with poor surface hardness can be obtained. Moreover, the obtained molded product is
When used at a temperature above the next transition point, crystallization progresses, resulting in poor shape stability. In addition, surface roughness occurs due to non-uniform crystallization within the mold, and this poses many problems as a resin for injection molding. Furthermore, some methods are used in which molding is performed at a mold temperature of around 50°C to obtain a molded product with almost no PET crystallization, and then heat treatment is performed, but this method is inefficient. However, it has drawbacks such as crystallization during heat treatment, resulting in volumetric shrinkage and deformation of the molded product. Therefore, PET molding is usually carried out using a special molding machine that can obtain a mold temperature of 130°C or higher, but such molding machines are not common, so the mold temperature commonly used is A PET resin that can be molded well using a molding machine at temperatures below 90-110°C has been desired. The present inventors conducted various studies to obtain a PET resin that has a low-temperature crystallization promoting effect that allows the crystallization of PET to proceed sufficiently even at a mold temperature of 100°C or less. He discovered that by blending sodium or potassium salts of , and polyalkylene glycol compounds, the objective could be achieved due to the synergistic effect of each of these components, and he filed a patent application (Japanese Unexamined Patent Publication No. 145943/1986).
No. 57-145145, etc.). However, it has been found that when the above additives are blended, the mechanical strength of the composition tends to decrease. The present inventors investigated a method for preventing such a decrease in mechanical strength, and found that the composition further contains a sterically hindered phenol and/or a compound of the general formula (R ₃ C ₃ H ₄ O) _x P(OR ₄ ) _y It has been discovered that by adding an organic phosphorus compound represented by the following, it is possible to prevent a decrease in mechanical strength, and the present invention has been achieved. Polyester resin (A) used in the present invention
has an intrinsic viscosity of at least 0.4 and at least 80 mol% of the constituent units consist of ethylene terephthalate units. filler reinforcement
In the case of PET resin molded products, generally when the intrinsic viscosity of the polymer is 0.4 or more, good mechanical properties are exhibited.
In particular, when the intrinsic viscosity is 0.5 or more, preferably 0.6 or more, a resin with well-balanced mechanical performance can be obtained. The resin composition of the present invention exhibits sufficient effects even when using a PET resin with a high intrinsic viscosity as described above, and injection molded products with sufficient crystallization can be produced at a mold temperature of 100°C or less. can get. In addition,
The intrinsic viscosity referred to here is a value measured at 30° C. in a mixed solvent of phenol/tetrachloroethane at a weight ratio of 1:1. Further, the polyester resin used in the present invention may contain components other than ethylene terephthalate units in a range of 20 mol% or less. Such copolymerizable components include:
Aromatic dicarboxylic acids such as isophthalic acid and naphthalene dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, diethylene glycol, 1,
4-butanediol, neopentyl glycol,
Examples include diols such as 2,2-bis(4-hydroxyphenyl)propane, and oxycarboxylic acids such as p-oxybenzoic acid. Reinforcing or filling materials used in the invention
(B) includes talc, clay, kaolin, mica,
Asbestos, wollastonite, silicates such as calcium silicate, inorganic fillers such as silica, gypsum, and graphite, and glass fibers, carbon fibers, graphite fibers, metal carbide fibers, metal nitride fibers, aramid fibers, and phenolic resin fibers. Examples include fibrous reinforcing agents such as. These reinforcing or filling materials may be used alone or in combination of two or more. These may be used as they are, or may be used after surface treatment or sizing agent treatment. Among the above-mentioned reinforcing or filling substances, glass fibers or a combination of glass fibers and mica are preferred because they significantly improve the heat resistance and mechanical properties of the molded product. The appropriate amount of the reinforcing or filling material (B) to be used is 10 to 140 parts by weight per 100 parts by weight of the polyester resin (A). If it is less than 10 parts by weight, sufficient effects cannot be obtained, and if it is less than 140 parts by weight,
If the amount exceeds 1 part by weight, the fluidity of the system becomes poor and molding becomes difficult. The sodium or potassium salt (including both totally and partially neutralized salts) of the carboxyl group-containing polymer used in the present invention (C) includes ethylene/ Sodium or potassium salts of copolymers of olefins such as methacrylic acid copolymers, ethylene/acrylic acid copolymers, and acrylic acid or methacrylic acid, aromatic olefins such as styrene/maleic anhydride copolymers, and maleic anhydride. Copolymers with sodium or potassium salts, etc. can be mentioned. In the above copolymer, the olefin or aromatic olefin preferably accounts for 50 to 98% by weight, particularly preferably 80 to 98% by weight. Also, a particularly preferred polymer is the sodium salt of an ethylene/methacrylic acid copolymer. The amount of component (C) used is based on 100 parts by weight of polyester resin (A).
0.05 to 20 parts by weight, preferably 0.1 to 10 parts by weight are suitable. If it exceeds 20 parts by weight, the extensibility properties of the molded product will deteriorate, and if it is less than 0.05 parts by weight, the effect of improving moldability will be insufficient. The general formula used in the present invention is R ₁ O(-R ₂ O) _-o R ₁ ' (R ₁ and R ₁ ' represent a lower alkyl group, and R ₂ represents an alkylene group having 2 to 4 carbon atoms. Also n
is a number of 5 or more. ) Poly(oxyalkylene) compound (D) represented by
Examples include dialkyl ethers of polyethylene glycol, polypropylene glycol, and polytetramethylene glycol (e.g. dimethyl ether, diethyl ether, dipropyl ether, etc.)
can be given. In the present invention, since a poly(oxyalkylene) compound in which both ends are alkyl ethers is used, there is little decrease in the intrinsic viscosity of the polyester resin during molding. The degree of polymerization n of component (D) must be 5 or more; if it is less than 5, component (D) tends to stand out on the surface of the molded product, which is not preferred. The appropriate amount of component (D) to be used is 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the polyester resin (A). If the amount is more than 10 parts by weight, the rigidity of the molded product will decrease, and if it is less than 0.1 part by weight, the effect of improving moldability will be insufficient, so it is unsuitable. The sterically hindered phenol used in the present invention preferably has a substituent at the 2,4,6-position, and has the general formula as well as Compounds represented by the following are preferably used. Here, n and m are integers of 1 to 4, R ₃ and R ₄ are monovalent to tetravalent aliphatic or aromatic groups depending on n and m, and tBu is a tertiary butyl group. More specifically, these compounds are 2,2′-
Methylenebis(4-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), Stearyl-β
(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl) Benzene, tetrakis [methylene-3(3',5'-di-t-butyl-4'-
Examples include hydroxyphenyl propionate] methane. In addition, examples of the organic phosphorus compound represented _by the general formula ( _{R 3} C ₆ H _{4 O} ) t-Butyl phenyl phosphite, tri-n-amyl phenyl phosphite, tri-t-aluminum phenyl phosphite, tri-n-hexyl phenyl phosphite, tri-n-octyl phenyl phosphite, tri- t-octyl phenyl phosphite, tri-t-nonylphenyl phosphite, octyl di-n-nonylphenyl phosphite, octyl di-n-nonyl phosphite, oleyl di-t-octyl phenyl phosphite, Examples include 2-ethylhexyldioctyl phenyl phosphorite. These sterically hindered phenols and organic phosphorus compounds may be used alone or in combination of two or more. In addition, the amount used is
The amount is 0.01 to 1 part by weight, preferably 0.05 to 0.5 part by weight, per 100 parts by weight of (A). If the amount used is less than 0.01 part by weight, the mechanical strength of the resin composition will be poor, and if it is more than 1 part by weight, embossment will occur on the surface of the molded product, causing yellowing of the molded product. This is not desirable as there is a risk of this happening. The composition of the present invention has a high crystallization rate even at relatively low temperatures, so even when molded at a mold temperature of about 80 to 100°C, which is usually used for molding general-purpose thermoplastic resins, the composition has a short mold residence time and is uniform throughout the surface layer. Moreover, a molded product that is highly crystallized and has excellent surface gloss can be obtained. The resulting molded product not only exhibits excellent dimensional stability and shape stability even at high temperatures, and extremely low warping deformation, but also exhibits excellent heat resistance.
Due to the combined use of component (E), it also has high mechanical properties and is extremely preferred as an engineering plastic material. In the composition of the present invention, in addition to the above-mentioned parts, additives commonly used in polyester resins,
For example, it may contain a colorant, a mold release agent, an ultraviolet stabilizer, a flame retardant, and the like. Moreover, if an epoxy compound is used in combination, even higher mechanical strength can be obtained. The composition of the present invention is produced by mixing each component by any known means. For example, the polyester resin may be mixed with components (B), (C), (D), and (E) in any suitable mixer or rotator and the mixture may be melt extruded or the final step in the polymerization of the polyester resin. Components (B), (C), (D), (E) are added to the molten resin.
It is also possible to mix and extrude as is. In addition, there are methods for melt-kneading components (C), (D), and (E) into polyester resin, and then blending component (B), and vice versa.
Components (C), (D), and (E) are added to polyester resin containing (B).
A method of melting and kneading can also be adopted. The composition of the present invention does not require any special molding method or reaction conditions, and can be molded under the same conditions as those used for molding ordinary thermoplastic resins. Hereinafter, the present invention will be explained in more detail with reference to Examples. All parts in the examples are by weight unless otherwise specified. Example 1 100 parts of PET (intrinsic viscosity 0.90), 8 parts of sodium salt of ethylene/methacrylic acid copolymer (Surlyn 1707 manufactured by Mitsui Polychemicals), 3 parts of polyethylene glycol dimethyl ether (average molecular weight of the polyethylene glycol portion 1000), Tetrakis [Methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate] methane (Irganox1010 manufactured by CIBA GEIGY) 0.3 parts, glass fiber (CS6PE401 manufactured by Nitto Boseki Co., Ltd., focused carbon fiber) After pre-mixing 50 parts of pud strand (cut length: 6 mm), use a 40 mmφ extruder (8VSE-40 manufactured by Osaka Seiki Kogyo Co., Ltd.).
- Type 28) into the hopper and check the cylinder temperature.
250-275-275-275℃, adapter temperature 265℃,
The mixture was extruded while melt-kneading at a die temperature of 265°C to obtain pellets. The extrusion was carried out smoothly and a well-dispersed pellet of glass fibers was obtained. After drying the obtained pellets under reduced pressure at 120℃ for 15 hours, the cylinder temperature was 240-260-280℃, the die temperature was 280℃,
A test piece was molded using an injection molding machine (model V-15-75 manufactured by Nikko Ankerperg Co., Ltd.) whose mold temperature was adjusted to 90°C. Table 1 shows the physical properties of the molded product obtained.
The composition of the present invention showed good moldability despite being molded in a low-temperature mold. Example 2 Mica 50 was used instead of glass fiber in Example 1.
Molding was carried out under the same conditions as in Example 1, except that 1. Table 1 shows the physical properties of the molded product obtained. Example 3 In Example 1, tetra extract [methylene-3
(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate] The procedure was carried out except that 0.3 part of trinonylphenyl phosphorite (Nokrac TNP manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.) was used instead of methane. Molding was carried out under the same conditions as in Example 1. Table 1 shows the physical properties of the molded product obtained. Example 4 Molding was carried out under the same conditions as in Example 1, except that 3 parts of polyethylene glycol dimethyl ether (average molecular weight of polyethylene glycol portion: 2000) was used instead of polyethylene glycol dimethyl ether (average molecular weight of polyethylene glycol portion: 1000) in Example 5. I went. Table 1 shows the physical properties of the molded product obtained. Example 5 In Example 1, 0.3 parts of trinonyl phenyl phosphite was added in addition to each component to create Example 1.
Molding was carried out under the same conditions. Table 1 shows the physical properties of the molded product obtained. Comparative Example 1 Molding was carried out under the same conditions as in Example 1 except that polyethylene glycol dimethyl ether was not used. The obtained molded product had irregularities on its surface and was of poor practical use. Comparative Example 2 Same as Example 1 except that the sterically hindered phenol tetrakis[methylene-3(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane in Example 1 was not used. Molding was carried out under these conditions. Table 1 shows the physical properties of the molded product obtained. As can be seen from Table 1, mechanical properties were found to be lower than those obtained in Examples or Comparative Examples. Comparative Example 3 Same as Example 4 except that the sterically hindered phenol Tetra Extract [methylene-3(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane was not used in Example 4. Molding was carried out under the same conditions. Table 1 shows the physical properties of the molded product obtained. Comparative Example 4 The same procedure as in Example 1 was carried out except that polyethylene glycol dimethyl ether and the sterically hindered phenol tetrakis[methylene-3(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane were not used. Molding was carried out under the same conditions as in Example 1. Table 1 shows the physical properties of the molded product obtained. As can be seen from the results in Table 1 for Comparative Examples 1 and 4, no substantial decrease in mechanical properties was observed in the compositions to which no poly(oxyalkylene) compound was added. 【table】

Claims (1)

[Claims] 1. (A) A polyester resin 100 having an intrinsic viscosity of at least 0.4 and in which at least 80 mol% of the constituent units are ethylene terephthalate units.
Parts by weight (B) 10-140 parts by weight of reinforcing or filler substances (C) 0.05-20 parts by weight of sodium or potassium salts of polymers containing carboxyl groups (D) General formula R ₁ O (-R ₂ O)- _{Poly ( _ _ _} oxyalkylene) compounds
0.1 to 10 parts by weight and (E) sterically hindered phenol and/or general formula (R ₃ C ₆ H ₄ O) _x P (OR ₄ ) _y (wherein R ₃ and R ₄ represent H or an alkyl group, x , y is 0 or an integer from 1 to 3 x+
Represents a number that satisfies y=3. ) A polyester resin composition comprising 0.01 to 1 part by weight of an organic phosphorus compound represented by: