JPH10273583A - Polyethylene terephthalate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having excellent processability and giving a molding excellent in mechanical properties, heat resistance and surface appearance by mixing a polyethylene terephthalate resin with an epoxy compound having an at least specified number of epoxy groups and a fibrous reinforcement in a specified ratio and specifying the inherent viscosity, molecular weight and molecular weight distribution of the mixed polyethylene terephthalate. SOLUTION: This composition comprises 100 pts.wt. polyethylene terephthalate resin having an intrinsic viscosity of 0.6-0.75 dl/g, 0.1-1 pt.wt. epoxy compound having at least three epoxy groups and 5-100 pts.wt. fibrous reinforcement and satisfies the requirements: the mixed polyethylene terephthalate has an intrinsic viscosity in the range: 0.58 < intrinsic viscosity < 0.70, a molecular weight in the range: 100,000 < weight-average molecular weight < 120,000 in terms of the molecular weight of polystyrene as measured by gel permeation chromatography and a molecular weight distribution in the range: 4.8 < weight-average molecular weight/number-average molecular weight < 6.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polyethylene terephthalate resin composition having excellent mechanical properties and heat resistance, as well as excellent fluidity, crystallization properties and surface appearance of a molded article.

[0002]

[Prior art]

[0003]

Since polyethylene terephthalate resin has excellent heat resistance, mechanical properties, chemical resistance and the like, it is mainly used as a molding material by compounding an inorganic reinforcing agent. A fibrous reinforcing agent is mainly used as an inorganic reinforcing agent. However, even if a large amount of reinforcing agent is used to improve strength and heat resistance, it does not improve more than a certain level. The appearance worsens. On the other hand, for the purpose of increasing the adhesion between the fibrous reinforcing agent and the polymer and improving the strength and heat resistance, an epoxy compound is used as described in JP-A-53-143649 and JP-A-6-212065. It has been proposed for use with fibrous reinforcing agents. However, even when the strength and heat resistance are improved by such a method, in order to obtain a great improvement effect, a decrease in the fluidity and crystallization rate of the polymer is inevitable, resulting in processing defects and molded article surface. The problem of deterioration of appearance arises.

Therefore, the present invention solves the above-mentioned problems of the prior art, and has excellent mechanical properties and heat resistance, and at the same time, has good workability.
It is an object to obtain a polyethylene terephthalate resin composition having excellent surface appearance of a molded article.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have reached the present invention.
That is, the present invention provides: "Based on 100 parts by weight of polyethylene terephthalate resin (a) having an intrinsic viscosity of 0.6 to 0.75 dl / g,
(B) 0.1 to 1 part by weight of an epoxy compound having three or more epoxy groups in one molecule and (c) fibrous reinforcing agent 5
-100 parts by weight, and the intrinsic viscosity of the polyethylene terephthalate after blending is expressed by the formula (1)

[Formula 3] 0.58 <Intrinsic viscosity (dl / g) <0.70 (1) and the molecular weight in terms of polystyrene measured by gel permeation chromatography is represented by the following formula (2) or (3).

(4) A polyethylene terephthalate resin composition characterized by satisfying 100000 <weight average molecular weight <120,000 (2) 4.8 <weight average molecular weight / number average molecular weight <6.0 (3). 1. 2. The polyethylene terephthalate resin composition according to any one of the above, wherein the epoxy compound is an epoxy compound having a glycidyl ether group. "In addition, any one of the above polyethylene terephthalates containing 0.1 to 3 parts by weight of a compound (d) selected from at least one of an inorganic layered compound, an alkali metal salt of an organic carboxylic acid and an alkaline earth metal salt of an organic carboxylic acid. 3. resin composition. ""100 parts by weight of a polyethylene terephthalate resin (a) having an intrinsic viscosity of 0.6 to 0.75 dl / g,
(B) 0.1 to 1 part by weight of an epoxy compound having three or more epoxy groups in one molecule and (c) fibrous reinforcing agent 5
-100 parts by weight, and the intrinsic viscosity of polyethylene terephthalate in the composition is represented by the formula (1)

[Formula 5] 0.58 <Intrinsic viscosity (dl / g) <0.70 (1) and the molecular weight in terms of polystyrene measured by gel permeation chromatography is represented by the following formula (2) or (3).

(6) A method for producing a polyethylene terephthalate resin composition that satisfies 100000 <weight average molecular weight <120,000 (2) 4.8 <weight average molecular weight / number average molecular weight <6.0 (3). ”, 5. "Polyethylene terephthalate and an epoxy compound are melt-kneaded at a temperature lower than the melting point of polyethylene terephthalate + 10 ° C., and then other components are melt-kneaded at a temperature equal to or higher than the melting point + 20 ° C. of the polyethylene terephthalate resin composition. Manufacturing method. "

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

[0007] The polyethylene terephthalate resin composition of the present invention comprises the following components.

[0008] The polyethylene terephthalate used in the present invention refers to a high-molecular-weight thermoplastic polyester having an ester bond in its main chain, using terephthalic acid as an acid component and ethylene glycol as a glycol component. Phthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, oxalic acid, adipic acid, 1,4-cyclohexanedicarboxylic acid, etc., as glycol components, propylene glycol, 1,4-butanediol,
1,6-hexanediol, 1,4-cyclohexanedimethanol, bisphenol A and the like can be used in a proportion of 20 mol% or less.

The intrinsic viscosity of polyethylene terephthalate blended in the resin composition of the present invention is 0.6 to 0.75 dl when measured at 25 ° C. using o-chlorophenol.
/ G.

The epoxy compound used in the present invention is:
An epoxy compound having three or more epoxy groups in one molecule such as glycidyl ether, glycidyl ester, and glycidylamine, and an epoxy compound having a glycidyl ether group is preferable. Specific examples include novolak-type epoxy compounds such as phenol and cresol,
Examples include resorcinol-type epoxy compounds, tetrahydroxyphenylmethane-type epoxy compounds, glycidyl ethers, and triglycidyl isocyanurate. The epoxy equivalent of these epoxy compounds is 90 to 280 g /
eq is preferable. Among these, one or more of the above epoxy compounds can be used in combination.

The amount of the epoxy compound added in the present invention is 0.1 to 100 parts by weight of polyethylene terephthalate.
It is 1 to 1 part by weight, preferably 0.2 to 1 part by weight.

The fibrous reinforcing agents used in the present invention include glass fibers, asbestos fibers, carbon fibers, graphite fibers, metal fibers, potassium titanate whiskers, aluminum borate whiskers, magnesium whiskers, and silicon whiskers. -, Wollastonite, sepiolite, asbestos, slag fiber, zonolite, elestadite, gypsum fiber, silica fiber, silica-alumina fiber,
Examples include zirconia fibers, boron nitride fibers, silicon nitride fibers, and boron fibers. Among these fibrous reinforcements,
Glass fibers are preferred.

[0013] These fibrous reinforcing agents are used for the purpose of the present invention.
As long as the physical properties are not impaired, those treated with a sizing agent or a coupling agent are preferable.

The amount of the fibrous reinforcing agent to be added is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, per 100 parts by weight of polyethylene terephthalate.

The molecular weight of polyethylene terephthalate in the resin composition of the present invention satisfies the following conditions. That is, the intrinsic viscosity measured at 25 ° C. using o-chlorophenol as a solvent is represented by the following formula (1):

[Formula 7] 0.58 <intrinsic viscosity (dl / g) <0.70 (1) and the molecular weight in terms of polystyrene measured by gel permeation chromatography is represented by the following formula (2) or (3).

[0000] 100000 <weight average molecular weight <120,000 (2) 4.8 <weight average molecular weight / number average molecular weight <6.0 (3) Only when such an optimum molecular weight distribution is obtained, the mechanical strength and heat resistance can be drastically improved without substantially deteriorating the fluidity and the crystallization speed. In the present invention, a compound (d) selected from at least one of an inorganic layered compound, an alkali metal salt of an organic carboxylic acid and an alkaline earth metal salt of an organic carboxylic acid can be further blended. These can act as crystallization promoters. The inorganic layered compound is an inorganic compound having a layered crystal structure in which unit crystal layers are stacked on each other, and preferably has an average particle size of 5 μm or less. Specific examples of the inorganic layer compound include clay minerals such as kaolinite group, antigolite group, smectite group, vermiculite group, and mica group.

The alkali metal salt of an organic carboxylic acid or alkaline earth metal salt of an organic carboxylic acid is an alkali metal salt or an alkaline earth metal salt of an aliphatic, alicyclic, aromatic or heterocyclic carboxylic acid. Salt. Specific examples include lithium acetate, sodium acetate, potassium acetate, calcium acetate, barium acetate, lithium propionate, sodium propionate, calcium propionate, sodium sebacate, potassium sebacate, calcium sebacate, sodium laurate, and lauric acid. Potassium, calcium laurate, barium laurate, sodium palmitate, potassium palmitate,
Calcium palmitate, sodium benzoate, potassium benzoate, calcium benzoate, sodium terephthalate, potassium terephthalate, calcium terephthalate, sodium phthalate, potassium phthalate, potassium cyclohexylcarboxylate, sodium trimellitate, potassium trimellitate , Sodium pyromellitate, potassium pyromellitate and the like.

When any one of the above compounds (d) is blended, the amount of addition is determined by adding the inorganic layered compound, the alkali metal salt of an organic carboxylic acid or the alkaline earth metal salt of an organic carboxylic acid to 100% of polyethylene terephthalate (a). 0.1 to 3 parts by weight based on parts by weight is preferred.

The composition of the present invention may contain conventional additives such as an ultraviolet absorber, a heat stabilizer, a lubricant, a release agent, a coloring agent including a dye and a pigment, and a colorant including a dye, in a range not to impair the object of the present invention. One or more kinds of fuels and the like can be further contained.

Small amounts of other thermoplastic resins (eg, polyethylene, acrylic resin, fluororesin, polyamide, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyphenylene sulfide, polyether ether ketone) , Polyacetal, polycarbonate, polysulfone, polyphenylene oxide, etc.), thermosetting resins (eg, phenolic resins, melamine resins, polyester resins, silicone resins, epoxy resins, etc.) and soft thermoplastic resins (eg, ethylene / vinyl acetate copolymer, polyester) Elastomers,
Ethylene / propylene terpolymer, ethylene / butene-1 copolymer, etc.).

The composition of the present invention can be used by adding a small amount of another inorganic filler within a range not to impair the object of the present invention. The inorganic filler herein means a particulate or flake-shaped filler, for example, glass beads, glass flake, diatomaceous earth, mica, sericite, zeolite, dolomite, fine silica powder, feldspar powder, potassium titanate, Shirasu balloon, magnesium hydroxide, aluminum hydroxide, calcium carbonate, magnesium carbonate,
Calcium sulfate, barium sulfate, calcium oxide, aluminum oxide, titanium oxide, magnesium oxide, zirconium oxide, aluminum silicate, silicon oxide, aluminum oxide, iron oxide, barium titanate, calcium fluoride, boron nitride, silicon nitride, metal powder , Novaculite, dawsonite, clay and carbon black.

When the above-mentioned additional components and other thermoplastic resins, thermosetting resins, soft thermoplastic resins and inorganic fillers are added to the composite material of the present invention, a known melt mixer, that is, a single-shaft or twin-shaft mixer is used. Extruders, Banbury mixers, kneaders, mixing rolls and the like can be used.

When the above composition is produced, polyethylene terephthalate and an epoxy compound are melt-kneaded near the melting point of polyethylene terephthalate, specifically at a temperature lower than the melting point + 10 ° C., and after the epoxy compound is well dispersed in polyethylene terephthalate, A method of melting and kneading together with other components at a temperature at which both can react, specifically, at a temperature equal to or higher than the melting point + 20 ° C., is preferable for obtaining the optimum molecular weight distribution specified in the present invention.

The obtained composition is usually prepared by injection molding,
It can be formed by any method such as extrusion. The obtained molded article has excellent heat resistance, mechanical properties, and surface appearance, and can be used for various applications such as electric / electronic parts, automobile parts, and mechanical parts.

[0024]

The present invention will be described in detail with reference to the following examples. All copies in the examples are on a weight basis.

The intrinsic viscosity of polyethylene terephthalate in the composition was measured at 25 ° C. after dissolving a sample in o-chlorophenol and filtering. The molecular weight in terms of polystyrene of polyethylene terephthalate in the composition is determined by dissolving the sample in hexafluoroisopropanol, filtering, and then measuring by gel permeation chromatography under the following conditions, using monodisperse polystyrene with a known molecular weight as a standard sample. It was determined from the third-order calibration curve obtained. Column: Shodex K-80M Mobile phase: hexafluoroisopropanol / methylene chloride (volume ratio = 3: 7) Temperature: 30 ° C. Flow rate: 1 mL / min Detector: UV (254 nm) The crystallization characteristics of the composition are indicated by differential scanning. Type thermal analyzer (DSC)
The temperature rises and falls at a rate of 20 ° C./min, and the difference (Tc−
Tcc). A higher value means better crystallization characteristics.

The epoxy compounds and crystallization accelerators used in this example and comparative examples are shown below. Epoxy compound A-1: Pentaerythritol tetraglycidyl ether (epoxy equivalent 230) A-2: Tetraglycidyl ether of 1,1,2,2-tetrakis- (p-hydroxyphenyl) ethane (epoxy equivalent 200) A-3: Triglycidyl tris (2-hydroxyethyl) isocyanurate (epoxy equivalent 240) A-4: o-cresol novolak type epoxy resin (epoxy equivalent 210) A-5: bisphenol-S-diglycidyl ether (epoxy equivalent 190) d component (Crystallization accelerator) B-1: Talc having an average particle size of 2.5 μm B-2: Barium stearate

Examples 1 to 8 Polyethylene terephthalate having an intrinsic viscosity of 0.65 dl / g, an epoxy compound, glass fiber (fiber diameter 10 μm, fiber length 3 mm), and a crystallization accelerator were used in the proportions shown in Table 1 and the diameter was 40 mm. The mixture was kneaded and compounded by a vent-type melt extruder to obtain pellets of the polyethylene terephthalate resin composition. At this time, the polyethylene terephthalate and the epoxy compound are preliminarily kneaded at 260 ° C., and then 290 ° C.
Then, the mixture was melt-kneaded including glass fibers and a crystallization accelerator added as necessary, and then cooled to obtain a resin composition. Using a screw-type injection molding machine the obtained resin composition,
A test piece was molded at a cylinder temperature of 275 ° C., a mold temperature of 130 ° C., and a molding cycle of 30 seconds. At this time, the minimum gauge pressure (short shot gauge pressure) required to completely fill the cavity of the mold was measured. Using this test piece, the tensile strength was determined in accordance with ASTM D638.
Flexural strength according to ASTM D790
The impact strength was measured according to D256, and the deflection temperature under load (1.82 MPa) was measured according to ASTM D648. Further, the appearance of the molded product was visually observed, and the presence or absence of surface roughness was evaluated.

The results are shown in Table 1.

Comparative Examples 1 to 7 Table 2 shows polyethylene terephthalate having an intrinsic viscosity of 0.65 dl / g, an epoxy compound, glass fiber (fiber diameter 10 μm, fiber length 3 mm) and, if necessary, a crystallization accelerator.
In the ratio shown in, without preliminary kneading, otherwise,
Melt and kneaded in the same manner as in Example 1 to obtain a resin composition,
Further, molding and evaluation were performed. The results are shown in Table 2.

Comparative Example 8 As in Comparative Example 1, polyethylene terephthalate having an intrinsic viscosity of 0.55 dl / g, an epoxy compound, glass fiber (fiber diameter 10 μm, fiber length 3 mm) and a crystallization accelerator were used in the proportions shown in Table 2. , Molding and evaluation. The results are shown in Table 2.

Comparative Example 9 Polyethylene terephthalate having an intrinsic viscosity of 0.8 dl / g, an epoxy compound, glass fiber (fiber diameter: 10 μm, fiber length: 3 mm), and a crystallization accelerator were used in the proportions shown in Table 2 as in Comparative Example 1. , Molding and evaluation. The results are shown in Table 2.

[0032]

[Table 1]

[0033]

[Table 2]

It can be seen that the polyethylene terephthalate resin compositions of the respective examples have excellent mechanical properties and heat resistance, as well as excellent fluidity, crystallization characteristics and molded article surface appearance.

[0035]

EFFECT OF THE INVENTION The polyethylene terephthalate resin composition of the present invention has excellent mechanical properties and heat resistance, as well as excellent fluidity, crystallization characteristics and surface appearance of a molded article.

Claims (5)

[Claims] 1. An epoxy compound (b) having three or more epoxy groups in one molecule per 100 parts by weight of a polyethylene terephthalate resin (a) having an intrinsic viscosity of 0.6 to 0.75 dl / g. To 1 part by weight (c) fibrous reinforcing agent
100 parts by weight, the intrinsic viscosity of the polyethylene terephthalate after compounding satisfies the following formula (1): 0.58 <intrinsic viscosity (dl / g) <0.70 (1), and the gel permeation chromatography The molecular weight in terms of polystyrene measured by chromatography satisfies the following formula (2) (3) 100000 <weight average molecular weight <120,000 (2) 4.8 <weight average molecular weight / number average molecular weight <6.0 (3) Polyethylene terephthalate resin composition. 2. The method according to claim 1, wherein the epoxy compound is an epoxy compound having a glycidyl ether group.
The polyethylene terephthalate resin composition according to the above. 3. A compound (d) selected from at least one selected from the group consisting of inorganic layered compounds, alkali metal salts of organic carboxylic acids and alkaline earth metal salts of organic carboxylic acids.
3. The polyethylene terephthalate resin composition according to claim 1, comprising 3 parts by weight. 4. 100 parts by weight of a polyethylene terephthalate resin (a) having an intrinsic viscosity of 0.6 to 0.75 dl / g, and (b) an epoxy compound having an epoxy compound having 3 or more epoxy groups in one molecule. Parts by weight and (c) 5 to 100 parts by weight of the fibrous reinforcing agent are melt-mixed, and the intrinsic viscosity of polyethylene terephthalate in the composition is expressed by the following formula (1): 0.58 <intrinsic viscosity ( dl / g) <0.70 (1) and the molecular weight in terms of polystyrene measured by gel permeation chromatography is the following formula (2) (3): 100000 <weight average molecular weight <120,000 (2) 4.8 <weight average molecular weight / number average molecular weight <6.0 A method for producing a polyethylene terephthalate resin composition that satisfies (3). 5. Melt-kneading a polyethylene terephthalate and an epoxy compound at a temperature lower than the melting point of polyethylene terephthalate + 10 ° C.
The method for producing a polyethylene terephthalate resin composition according to claim 4, wherein the mixture is melt-kneaded at the above temperature.