JPS6318974B2 - - 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, 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) 10 to 140 parts by weight of glass fiber (C) Carbon Sodium salt or potassium salt of a carboxylic acid having a number of 7 to 25, or a sodium salt or potassium salt of a polymer containing a carboxyl group
0.05 to 20 parts by weight (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 a carbon number of 2 to 4. Represents an alkylene group.N is a number of 5 or more.) Polyalkylene glycol 0.1~
10 parts by weight (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. basis,
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 ) and 1 to 6 parts by weight of (F) talc,
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 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, in some cases, molding is performed at a mold temperature of around 50°C to obtain a molded product in which the PET is hardly crystallized, and then heat treatment is performed, but this method is only 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. As a result of various studies in order to obtain a PET resin that sufficiently progresses in crystallization even at a mold temperature of 100°C or lower, the present inventors found that sodium or potassium salts of carboxylic acids having 7 to 25 carbon atoms, or carboxyl groups It was discovered that the object could be achieved by adding a sodium or potassium salt of a polymer having the following, and a polyalkylene glycol compound, and a patent application was previously filed. However, the molded product obtained from the above composition involves a sacrifice in mechanical strength because it contains a polyalkylene glycol compound, which can be called a plasticizer.
The present inventors found that even though a soft substance called a polyalkylene glycol compound was blended, crystallization still occurred.
As a result of continuing intensive studies in order to achieve the high rigidity inherent to PET, we found that when glass fiber is used as the main reinforcing agent, by combining it with an epoxy compound and talc, it does not impair moldability. The present invention was achieved by discovering that a dramatic improvement in mechanical strength can be achieved. Hereinafter, the composition of the present invention will be explained in detail. 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. The glass fiber (B) used in the present invention may be any ordinary glass fiber used for reinforcing plastics, and preferably has a diameter of 3 to 30 microns. Depending on the manufacturing method, various forms such as roving or chopped strands can be used. The glass fibers are preferably treated with silane treatment, chromium treatment, or the like for the purpose of improving adhesion to plastics. The appropriate amount is 10 to 140 parts by weight, preferably 20 to 100 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 exceeds 140 parts by weight, the fluidity of the system becomes poor and molding becomes difficult. Sodium or potassium salts of carboxylic acids having 7 to 25 carbon atoms used in the present invention, or sodium or potassium salts of polymers containing carboxyl groups (totally neutralized salts and partially neutralized salts) Examples of (C) include sodium salts or potassium salts of stearic acid, pelargonic acid, behenic acid, etc., and olefins such as ethylene/methacrylic acid copolymers, ethylene/acrylic acid copolymers, etc. Examples include sodium or potassium salts of copolymers with acrylic acid or methacrylic acid, and sodium or potassium salts of copolymers of aromatic olefins and maleic anhydride such as styrene/maleic anhydride copolymers. Among these, sodium salts or potassium salts of polymers containing carboxyl groups are preferably used because they cause less decrease in the viscosity of the polyester resin during molding. 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 appropriate amount of component (C) to be used is 0.05 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the polyester resin (A).
If it exceeds 20 parts by weight, the mechanical properties of the molded product will deteriorate, and if it exceeds 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 H or a lower alkyl group,
R ₂ represents an alkylene group having 2 to 4 carbon atoms. 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 intrinsic viscosity of the polyester resin during molding will decrease significantly, so when using these, it is necessary to use a high degree of polymerization. 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 per 100 parts by weight, preferably 1
~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, so it is unsuitable. General formula used in the present invention (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. , arylene group, alkalylene group, or aralkylene group, and these groups may have an ether group or ester group. Glycol diglycidyl ether, butanediol-1,4-diglycidyl ether, hexanediol-1,6-diglycidyl ether, 1,4-dimethylolcyclohexane diglycidyl ether, 1,1-trimethylolpropane triglycidyl ether, hexadiene -1,5-diepoxide, P,P'-dioxy-
Diglycidyl ether of 2,2-diphenylpropane, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, diglycidyl ether of ethylene glycol/propylene glycol copolymer, polybutylene glycol diglycidyl ether, polyneopentyl glycol diglycidyl Ether etc. can be given. The amount of these epoxy compounds used is 0.1 parts by weight per 100 parts by weight of the polyester resin (A).
~3 parts by weight is suitable. 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. Also,
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. In the present invention, talc (hydrated magnesium silicate, mainly 3MgO.4SiO ₂ .nH ₂ O) is used in an amount of 1 to 6 parts by weight based on 100 parts by weight of the polyester resin (A). If the amount of talc added is less than 1 part by weight, the effect of improving mechanical properties will not be sufficient, and if it is more than 6 parts by weight, fluidity during molding will decrease and molding will become difficult, which is not preferred. The present invention is characterized by the combined use of glass fiber, epoxy compound, and talc.
If any of them is missing, sufficient improvement in mechanical properties cannot be obtained. Generally, methods for improving the mechanical properties of synthetic resins using glass fibers and epoxy compounds are known, and talc is also known as a reinforcing agent for synthetic resins, but talc is In contrast, in the present invention, a significant effect is achieved with a small amount, whereas the reinforcing effect is hardly achieved unless 20 parts by weight or more is added. Therefore, such an effect is considered to be unique to the system of the present invention using polyalkylene glycol. 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 can be uniformly molded to the surface layer with a short mold residence time. 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.
It also has high mechanical properties, especially high flexural modulus, making it extremely desirable as an engineering plastic material. 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 manufactured by mixing each component by any known means. For example, the polyester resin may be mixed with components (B), (C), (D), (E), and (F) in any suitable mixer or rotating machine and the mixture may be melt extruded or In the final stage of polymerization, components (B), (C),
(D), (E), and (F) can also be mixed and extruded as is. In addition, components (C), (D),
After melt-kneading (E), components (B) and (F) are blended, and conversely, components (C), (D), (E), and (F) are added to a polyester resin containing component (B). ) 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 through implementation. All parts in the examples are by weight unless otherwise specified. Example 1 100 parts of PET (intrinsic viscosity 0.68), 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), Bis Phenol A
Diglycidyl ether (Epicote 828 manufactured by Ciel Kagaku Co., Ltd.) 0.3 parts, talc (MICEL manufactured by Hayashi Kasei Co., Ltd.)
After premixing 5 parts of TONE, particle size distribution D50 = 1.6μ) and 50 parts of glass fiber (CS6PE401 manufactured by Nitto Boseki Co., Ltd., bundled chopped strands, cut length 6 mm), the mixture was heated using a 40 mmφ extruder (8VSE manufactured by Osaka Seiki Kogyo Co., Ltd.). -40
- 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 Ankelberg 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 Molding was carried out under the same conditions as in Example 1, except that 0.3 parts of sodium stearate was used instead of the sodium salt of the ethylene/methacrylic acid copolymer. Table 1 shows the physical properties of the molded product obtained. Example 3 In Example 1, PET with an intrinsic viscosity of 0.78 was used, and instead of polyethylene glycol dimethyl ether, polyethylene glycol (average molecular weight
Molding was carried out under the same conditions as in Example 1 except that 3 parts (1000) were used. Table 1 shows the physical properties of the molded product obtained. When polyethylene glycol whose ends are not dialkyl ethers is used, the intrinsic viscosity of PET is greatly reduced. Example 4 Molding was carried out under the same conditions as in Example 1 except that 1 part of polyethylene glycol diglycidyl ether (average molecular weight 1000) was used instead of bisphenol A diglycidyl ether. Table 1 shows the physical properties of the molded product. The moldability was good and the mechanical properties of the molded product were well balanced. Example 5 Molding was carried out under the same conditions as in Example 1 except that 3 parts of polyethylene glycol dimethyl ether having an average molecular weight of 2000 in the polyethylene glycol portion was used. Table 1 shows the physical properties of the molded product. 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 poor in practical use. Comparative Example 2 Molding was carried out under the same conditions as in Example 1 except that the amount of polyethylene glycol dimethyl ether was changed to 11 parts. Table 1 shows the physical properties of the molded product. The resin has good fluidity during molding,
Although the molded product had good surface smoothness, it had poor rigidity due to the large amount of plasticizer blended. Comparative Example 3 Molding was carried out under the same conditions as in Example 1 except that the amount of sodium salt of ethylene/methacrylic acid copolymer was 0.04 parts. Table 1 shows the physical properties of the molded product obtained. The molded product had poor surface smoothness and poor dimensional stability during annealing, so under these molding conditions PET
It seems that it is not sufficiently crystallized. Furthermore, despite the small amount of the sodium salt of ethylene/methacrylic acid copolymer (component (C)), which has a small elastic modulus, both the tensile strength and the bending strength are lower than in Example 1. Comparative Example 4 Example 1 except that the amount of bisphenol A diglycidyl ether in Example 1 was 4 parts.
When each component was kneaded and melt-extruded under the same conditions as above, the viscosity of the system suddenly increased and the cylinder torque increased, so extrusion was stopped. Comparative Example 5 Molding was carried out under the same conditions as in Example 1 except that 0.5 part of talc was used. Table 1 shows the physical properties of the molded product. This shows that when the amount of talc used is small, the mechanical properties, especially the flexural modulus, become low. 【table】

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) 10 to 140 parts by weight of glass fiber ( C) Sodium or potassium salts of carboxylic acids having 7 to 25 carbon atoms, or sodium or potassium salts of polymers containing carboxyl groups.
0.05 to 20 parts by weight (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 a carbon number of 2 to 4. Represents an alkylene group.N is a number of 5 or more.) Polyalkylene glycol 0.1~
10 parts by weight (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. basis,
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 polyethylene terephthalate resin composition comprising 0.1 to 3 parts by weight of an epoxy compound represented by (F) and 1 to 6 parts by weight of talc. 2. The composition according to claim 1, wherein component (C) is a sodium salt or potassium salt of a polymer containing a carboxyl group. 3. The composition according to claim 1, wherein R ₁ and R ₁ ' of component (D) are lower alkyl groups.