JPH0253462B2 - - 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, it mainly includes: (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) 30 to 160 parts by weight of a reinforcing or filling substance; ) 1 to 20 parts by weight of a compound that is a mono- to trivalent metal salt of a copolymer of α-olefin and α, β-unsaturated carboxylic acid and has a molecular weight of less than 5000, and (D) general formula R ₁ O (-R ₂ O) - _o R ₁ ′ (where R ₁ and R ₁ ′ represent H or a lower alkyl group, R ₂ represents an alkylene group having 2 to 4 carbon atoms, and n is a number of 5 or more. ) Polyalkylene glycol 0.1~
A polyester resin composition composed of 10 parts by weight, and further to the composition, (E) General formula (However, R ₃ and R ₃ ′ represent H, an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group, and R ₃ and R ₃ ′ may be bonded to each other. R ₄ represents an alkylene group or a cycloalkylene group. base,
It represents an arylene group, an alkalylene group, or an aralkylene group, and these groups may have an ether group or an ester group. ) Regarding a polyester resin composition formed by blending 0.1 to 3 parts by weight of an epoxy compound represented by
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 100°C or less and provides molded products 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, PET reinforced with inorganic fillers such as glass fiber has thermal properties,
Since it has significantly improved mechanical properties, it has been widely used in engineering plastics and other applications in recent years. 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 carried out at a mold temperature below, it is difficult to obtain a molded product with good crystallization, and a molded product with poor surface hardness cannot 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 since such molding machines are not common, 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. In order to solve the above problems, various methods have been proposed to improve the moldability of PET. Among them, metal salt compounds of organic carboxylic acids are particularly effective as crystallization promoters, and alkali metal salts of aromatic or aliphatic carboxylic acids such as sodium benzoate and sodium stearate are used as crystallization promoters.
It was proposed in No. 29977 and Japanese Patent Publication No. 47-14502. However, adding these compounds causes problems during molding.
There is a problem that the molecular weight of PET decreases rapidly. In addition, in Japanese Patent Publication No. 45-26225, 1
-Addition of ionic copolymers containing trivalent metal ions has been proposed. However, this publication discloses that the molecular weight of the ionic copolymer must be 5,000 or more, and subsequent research has focused exclusively on the addition of high molecular weight ionic copolymers. Furthermore, in recent years, attempts have been made to obtain even better moldability by blending compounds that can be called plasticizers for PET together with these crystallization promoters. The present inventors also found that if a polyalkylene glycol compound is used in combination with a metal salt of an organic carboxylic acid or a copolymer of an α-olefin and a metal salt of an α,β-unsaturated carboxylic acid, the crystallization rate will be extremely high. It was discovered that a resin composition with a large amount of water could be obtained, and a patent application was filed as Japanese Patent Application No. 32135/1983. Furthermore, a rapidly crystallizing thermoplastic polyester resin composition comprising a thermoplastic polyester blended with an ionic copolymer and a polyalkylene glycol has also been proposed in JP-A-56-127655. However, when such a system is filled with a large amount of filler such as glass fiber, the fluidity of the composition when melted becomes extremely poor, and the amount of filler filled must be too large in order to use it for injection molding. I couldn't do it. As a result of intensive studies on methods for improving melt fluidity without reducing the crystallization rate, the present inventors found that α-
The inventors have discovered that the object can be achieved by using a mono- to trivalent metal salt of a copolymer of olefin and α,β-unsaturated carboxylic acid together with a polyalkylene glycol compound, and have arrived at the present invention. 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. As the crystallization rate decreases as the intrinsic viscosity increases, it is difficult for conventional crystallization accelerators to be effective, but the resin composition of the present invention can be The effect is sufficiently expressed, and an injection molded product with sufficiently advanced crystallization can be obtained at a mold temperature of 100°C or less. Note that the intrinsic viscosity referred to herein 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,
Examples include diols such as 1,4-butanediol, neopentyl glycol, and 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,
Silicates such as asbestos, wollastonite, calcium silicate, inorganic fillers such as silica, gypsum, graphite, glass fibers, carbon fibers, graphite fibers, metal carbide fibers, metal nitride fibers,
Examples include fibrous reinforcing agents such as aramid fibers and phenolic resin fibers. These reinforcing or filling materials may be used alone or in combination of two or more. Further, 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 amount of reinforcing or filling material (B) used is the same as that of polyester resin (A)
A suitable amount is 30 to 160 parts by weight per 100 parts by weight.
If it is less than 30 parts by weight, a sufficient reinforcing effect cannot be obtained, and if it exceeds 160 parts by weight, the fluidity of the system becomes poor and molding becomes difficult. 1 to 3 of copolymers of α-olefin and α,β-unsaturated carboxylic acid used in the present invention
Valid metal salts (including both totally neutralized salts and partially neutralized salts) include, for example, α-olefins such as ethylene/methacrylic acid copolymers, ethylene/acrylic acid copolymers, etc. α- of sodium or potassium salts of copolymers with acrylic acid or methacrylic acid, styrene/maleic anhydride copolymers, ethylene/maleic anhydride copolymers, etc.
Examples include sodium or potassium salts of copolymers of olefin and maleic anhydride. Furthermore, a graft copolymer can also be used as the ionic copolymer. Such a copolymer is produced by, for example, grafting an α,β-unsaturated carboxylic acid ester onto a polyolefin, saponifying the same, and
It can then be obtained by, for example, reacting with an alkali metal hydroxide. Further, in the above copolymer, the olefin or aromatic olefin preferably accounts for 50 to 98% by weight of the copolymer, particularly preferably 80 to 98% by weight. Also, a particularly preferred polymer is the sodium salt of an ethylene/methacrylic acid copolymer. The molecular weight of these ionic copolymers must be less than 5,000. Even if a polymer having a molecular weight of 5,000 or more is used, the melt fluidity not only does not improve, but also the fluidity may decrease, which is not preferable. The amount of component (C) used is 1 per 100 parts by weight of polyester resin (A).
~20 parts by weight, preferably 2 to 10 parts by weight are suitable. If it exceeds 20 parts by weight, the mechanical properties of the molded product will deteriorate, and if it is less than 1 part by weight, the effect of improving fluidity during melting will not be sufficiently expressed, and the effect of promoting crystallization will also 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 H or a lower alkyl group, and R ₂ represents an alkylene group having 2 to 4 carbon atoms. represent
Further, n is a number of 5 or more. ) Examples of the polyalkylene glycol (D) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and their mono- or dialkyl ethers (for example, monomethyl or dimethyl ether, monoethyl or diethyl ether, monopropyl or dipropyl ether, monobutyl or dibutyl ether, etc.). In the present invention, it is preferable that the polyalkylene glycol has alkyl ethers at both ends, since the inherent viscosity of the polyester resin during molding is less likely to decrease. If a monoalkyl ether in which only one end is etherified or a polyalkylene glycol in which both ends are hydroxyl groups are used, the inherent viscosity of the polyester resin during molding will decrease significantly. It is necessary to use a polyester resin of The degree of polymerization n of component (D) is 5
If it is less than 5, component (D) tends to stand out on the surface of the molded product, which is not preferable. The amount of component (D) used is polyester resin (A)
0.1 to 10 parts by weight, preferably 1 part by weight per 100 parts by weight
~5 parts by weight is suitable. 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, which is inappropriate. In the present invention, when a molded article with particularly high mechanical properties is required, the general formula (However, R ₃ and R ₃ represent H, an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group, and R ₃ and R ₃ ' may be bonded to each other. _{R 4}
represents an alkylene group, a cycloalkylene group, an arylene group, an alkalylene group, or an aralkylene group, and these groups may have an ether group or an ester group. ) It is preferable to use the epoxide compound (E) represented by: The property-improving effect of component (E) is particularly significant when used in combination with component (C). Specific examples of component (E) include ethylene glycol diglycidyl ether, butanediol-1,4-diglycidyl ether, hexanediol-1,6-diglycidyl ether, and 1,4-dimethylolcyclohexane diglycidyl ether. , 1,1-trimethylolpropane triglycidyl ether, hexadiene-1,5-diepoxide, p,p'-dioxy-2,2-diphenylpropane diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether , diglycidyl ether of ethylene glycol/propylene glycol copolymer, polybutylene glycol diglycidyl ether, polyneopentyl glycol diglycidyl ether, and the like. The appropriate amount of these epoxy compounds to be used is 0.1 to 3 parts by weight per 100 parts by weight of the polyester resin (A). If the amount exceeds 3 parts by weight, a large amount of crosslinking reaction will occur during molding, resulting in extremely poor fluidity during melting, which is unsuitable.
Furthermore, if the amount is less than 0.1 part by weight, the effect of improving the mechanical properties of the molded product will not be sufficient. The composition of the present invention suppresses the molecular weight reduction of PET as much as possible, has excellent melt flowability during molding, and has a high crystallization rate even at relatively low temperatures. Even when molding is carried out at the mold temperature, a molded product that is uniformly and highly crystallized to the surface layer and has excellent surface gloss can be obtained with a short mold residence time. The resulting molded product not only has excellent dimensional stability and shape stability even at high temperatures, exhibits excellent heat resistance with extremely low warping deformation, but also exhibits high mechanical properties when used in combination with component (E). In combination, it is extremely preferable as an engineering plastic material. Although the reason why the composition of the present invention has excellent moldability is not clear, the moldability of polyester resin is improved due to the synergistic effect of the crystallization nucleating effect of component (C) and the plasticizing effect of component (D). It is thought that this is because the Further, it is presumed that by using component (E), a crosslinking reaction occurs appropriately and the elastic modulus is improved. In the composition of the present invention, in addition to the above-mentioned components, additives commonly used in polyester resins,
For example, it can contain colorants, mold release agents, antioxidants, ultraviolet stabilizers, flame retardants, and the like. The composition of the present invention is produced by combining the components by any known means. For example, the polyester resin may be mixed with components (B), (C), (D), [or even (E)] in any suitable mixer or rotator, and the mixture may be melt extruded or It is also possible to mix components (B), (C), (D), [or further (E)] into the molten resin at the final stage of polymerization and extrude the mixture as it is. In addition, a method of melt-kneading components (C), (D), [or further (E)] into a polyester resin, and then blending component (B), and conversely, a method of blending component (B) into a polyester resin containing component (B), (C),
A method of melting and kneading (D), [or further (E)] 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. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way. Example 1 43.5 g of PET (intrinsic viscosity 0.68), sodium salt of ethylene/methacrylic acid copolymer (average molecular weight
3000) 3.5g, polyethylene glycol dimethyl ether (average molecular weight of polyethylene glycol portion 1000) 1.3g, glass fiber (manufactured by Nittobo Co., Ltd.)
Knead 21.7g of CS6PE401 (focused chopped strand, cut length 6mm) at 275℃ and 30rpm for 5 minutes using a Plastograph (Brabender PL-3000 model, mixing section capacity 70ml, 1 pair of roller type rotors installed) The kneading torque after 5 minutes is shown in Table 1.A sample of the obtained kneaded material was rapidly cooled using a differential calorimeter (hereinafter abbreviated as DSC, model 2C manufactured by PerkinElmer) from room temperature to 20°C. The crystallization temperature (Thc) was measured by raising the temperature at a rate of /min.The lower the Thc, the faster the crystallization rate of the polymer at low temperatures, and the higher the crystallization rate of the molded product when actually molded in a low-temperature mold. Comparative Example 1 Kneading was carried out under the same conditions as in Example 1 except that 3.5 g of a sodium salt of an ethylene/methacrylic acid copolymer having an average molecular weight of 200,000 was used. Thc composition
are shown in Table 1. Example 2 Kneading was carried out under the same conditions as in Example 1 except that 1.3 g of polyethylene glycol dimethyl ether having an average molecular weight of 2000 in the polyethylene glycol portion was used. Table 1 shows the kneading torque and Thc of the obtained composition. Example 3 In addition to the ingredients used in Example 1, 0.13 g of bisphenol A diglycidyl ether was added,
Kneading was carried out under exactly the same conditions as in Example 1. Table 1 shows the kneading torque and Thc of the obtained composition. Comparative Example 2 Kneading was carried out under the same conditions as in Example 3, except that the sodium salt of the ethylene/methacrylic acid copolymer having an average molecular weight of 50,000 was used. Table 1 shows the kneading torque and Thc of the obtained composition.
Shown below. Comparative example 3 PET 43.5g with intrinsic viscosity 0.63, glass fiber 21.7g
were kneaded using a plastograph under the same conditions as in Example 1. The kneading torque and Thc are shown in Table 1. Comparative Example 4 In Example 3, kneading was carried out under the same conditions as in Example 3 except that a sodium salt of an ethylene/methacrylic acid copolymer having an average molecular weight of 7000 was used. Table 1 shows the kneading torque and Tch of the obtained composition.

[Table] As can be seen from the table, the composition of the present invention
The kneading torque is lower than that in the case of using it alone (Comparative Example 3). On the other hand, in 1, 2, and 4, which use sodium salt of ethylene/methacrylic acid copolymer with a molecular weight of 5000 or more, the kneading torque is higher than that of PET alone, making it difficult to blend a large amount of filler. It shows that. Furthermore, there is no difference in Thc between the composition of the present invention and those of Comparative Examples 1, 2, and 4, and the crystallization promoting effect of the composition of the present invention is due to the sodium content of the ethylene/methacrylic acid copolymer with a molecular weight of 5000 or more. It can be seen that the results are equivalent to those using salt.

Claims (1)

[Scope of Claims] 1. Mainly (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) 30 to 160 parts by weight of reinforcing or filling substances Part (C) 1 to 20 parts by weight of a compound that is a mono- to trivalent metal salt of a copolymer of α-olefin and α, β-unsaturated carboxylic acid and has a molecular weight of less than 5000, and (D) General formula R ₁ O (-R ₂ O) - _o R ₁ ' (where R ₁ and R ₁ ' represent H or a lower alkyl group, R ₂ represents an alkylene group having 2 to 4 carbon atoms, and n is 5 polyalkylene glycol represented by 0.1~
A polyester resin composition composed of 10 parts by weight. 2. The composition according to claim 1, wherein R ₁ and R ₁ ' of component (D) are lower alkyl groups. 3 Mainly (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) 30 to 160 parts by weight of a reinforcing or filling substance (C) α- 1 to 20 parts by weight of a mono- to trivalent metal salt of a copolymer of olefin and α,β-unsaturated carboxylic acid and having a molecular weight of less than 5000 (D) General formula R ₁ O(-R ₂ O) - _o R ₁ ' (However, R ₁ and R ₁ ' represent H or 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.) Polyalkylene glycol represented by 0.1~
10 parts by weight and (E) general formula (However, R ₃ and R ₃ ′ represent H, an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group, and R ₃ and R ₃ ′ may be bonded to each other. R ₄ represents an alkylene group or a cycloalkylene group. base,
It represents an arylene group, an alkalylene group, or an aralkylene group, and these groups may have an ether group or an ester group. ) A polyester resin composition comprising 0.1 to 3 parts by weight of an epoxy compound represented by: 4. The composition according to claim 3, wherein R ₁ and R ₁ ' of component (D) are lower alkyl groups.