JPS59204655A - Polyethylene terephthalate resin composition - Google Patents

Abstract

PURPOSE:To provide the titled composition having excellent moldability and mold-release property, and increased rate of crystallization to enable the sufficient crystallization even in a low-temperature mold, by compounding glass fiber, a specific organic carboxylic acid metal salt, a specific epoxy compound, and a specific benzoic acid ester. CONSTITUTION:(A) 30-85wt% of polyethylene terephthalate resin is compounded with (B) 5-60wt% of glass fiber (having fiber length of preferably 0.4-6mm.), (C) 0.03-5wt% of an organic carboxylic acid salt of a metal of the I a-group or IIa- group of the periodic table, (D) 0.1-10wt% of the epoxy compound of formula I (R1 is >=6C hydrocarbon group of halogenated hydrocarbon group; R2 is 2-6C alkylene; n is 0 or >=1), e.g. polyethylene glycol monolauryl monoglycidyl ether, and (E) 0.1-10wt% of the benzoic acid ester of formula II (R is 2-6C alkylene; n>=1), e.g. ethylene glycol dibenzoate. The sum of the above components is 100wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly crystalline monoglass fiber reinforced polyethylene terephthalate resin composition having excellent moldability, mold release properties and dimensional stability.

Glass fiber reinforced polyethylene terephthalate resins are widely used because they have excellent mechanical properties, chemical resistance, and the like. However, crystalline polymers such as polyethylene terephthalate resin have the characteristic that their various properties strongly depend on the degree of crystallinity. Therefore, if these reinforced resins are molded at a mold temperature of 100°C or less. Since crystallization does not proceed sufficiently, the moldability is poor, and the heat distortion temperature is low at around 100°C, so the heat resistance is poor. Known methods for promoting crystallization include a method in which a molded article obtained in a partially crystallized state is subjected to post-heat treatment to advance crystallization, and a method in which the molded article is immersed in a liquid that promotes crystallization. However, these methods require post-processing after molding, and have the disadvantage that the molded product is easily deformed during post-processing. Therefore, in general, the mold temperature is
A method is used in which crystallization is sufficiently advanced during molding by increasing the temperature to a high temperature of 20 to 150'C, but the use of high temperature molds is disadvantageous in terms of economy and work safety.

In order to improve this point, a method of adding a crystal nucleating agent such as a metal salt of an organic carboxylic acid or an inorganic compound has been proposed.

However, this method has poor mold releasability (and requires a long cooling time) when molding is performed at a mold temperature of 100° C. or lower.

Benzoic acid varnish is known as another crystallization accelerator (JP-A-54-139654 and JP-A No. 55-54).
(Refer to each publication No. 161844). 'The inventor is
Furthermore, when various crystallization promoters were investigated, it was discovered that crystallization can be more effectively promoted by using benzoic acid esters and a specific monoepoxy compound in combination.

The present invention provides (A) polyethylene terephthalate resin 6
0-85% by weight, CB) Glass fiber 5-60% by weight, (
C) 0.03 to 5% by weight of an organic carboxylic acid salt of a metal in group Ⅰ a or group Ⅰ a of the periodic table, (D> general formula (wherein R1 is a hydrocarbon group having 6 or more carbon atoms or a halogenated a hydrocarbon group, R2 is an aralkylene group having 2 to 6 carbon atoms,
(n is an integer of 0 or 1 or more) 0.1 to 10% by weight of an epoxy compound represented by (E) general formula (wherein R is an alkylene group having 2 to 2 carbon atoms, n is an integer of 1 or more 0.1 to 1 benzoic acid ester represented by
It is a polyethylene terephthalate resin composition consisting of 0% by weight (total of each component is 100% by weight).

The resin composition of the present invention has improved crystallization rate and excellent moldability and mold release properties, especially in low-temperature molding.
This is its characteristic.

■ That is, by adding the general formula ρ monoepoxy compound and the benzoic acid ester of the general formula ■ to the glass fiber reinforced polyethylene terephthalate resin at the same time, the compound exists as a terminal group of the polyethylene terephthalate resin by heating during extrusion and molding. The carboxyl group reacts with the monoepoxy compound, and long-chain alkyl groups, phenyl groups, polyoxyalkylene chains, etc. are introduced at the end of the polyester, thereby improving the compatibility between the added benzoic acid ester and the polyethylene terephthalate resin. It is presumed that this improves the polyethylene terephthalate, plasticizes the polyethylene terephthalate more effectively, and improves the crystallization rate. Therefore, the crystallization rate can be improved with a smaller amount added than when only benzoic acid ester is added.

The polyethylene terephthalate-based resin (A) used in the present invention includes a linear polyethylene terephthalate homopolymer having ethylene terephthalate units as a constituent unit, a copolymer obtained by copolymerizing this with a small amount of other copolymerizable components, and homopolymers of these. Examples include mixtures of polymers and copolymers. Components that can be copolymerized here include conventionally known acid components and glycol components, such as isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid,
Acid components such as diphenyl ether-4,4'-dicarboxylic acid, adipic acid, and cepatic acid, propylene glycol,
Examples include glycol components such as phtylene glycol, neohentyl glycol, cyclohexane dimetatool, 2,2-bis(4-hydroxyphenyl)propane, and oxyacids such as p-hydroxybenzoic acid and p-hydroxyethoxybenzoic acid. It will be done.

Polyethylene terephthalate resins can be obtained by polycondensation through transesterification or direct esterification, but their intrinsic viscosity [η
] is preferably in the range of 0.4 to 1.4. A polymer having a large intrinsic viscosity [η] can be obtained by a conventional polymerization method and can be subjected to a known solid phase polymerization method.

Note that [η] is phenol/tetrachloroethane-507
50 (weight ratio) This is a value determined from the solution viscosity measured in Solution 1 at 25°C.

The blending amount of the polyethylene terephthalate resin (A) is 60 to 85% by weight based on the total resin composition. 30% by weight
If it is less than 85% by weight, the flowability of the resin composition may deteriorate, and if it is more than 85% by weight, the moldability in a low-temperature mold will be poor, which is not preferable.

Glass fiber (B) is 5 to 6% by weight based on the total resin composition.
Used within the range of If the blending amount of glass fiber exceeds 60% by weight, the fluidity processability will decrease, and if it is less than 5% by weight, the reinforcing effect of the glass fiber will be small, which is not preferable. The type of glass fibers and the method of mixing them are not particularly limited, and both roving type and chopped strand type can be used, but from the viewpoint of productivity, chopped strand type is preferable. In addition, considering workability during mixing, wear of the molding machine, and cutting during the molding process, the fiber length of glass fibers during mixing is 0.4~
A fiber length of about 6 mm is particularly preferable, and it is sufficient if the fiber length of the glass fiber in the final molded product is about 0.2 to 2 mm. As the glass fiber, commercially available products that have been subjected to various treatments can be used as they are.

The metal salt of the specific organic carboxylic acid used in the present invention (C
) has an effect as a crystal nucleating agent for polyethylene terephthalate resin, and metal salts of organic carboxylic acids of group Ⅰ a or group Ⅰ a of the periodic table are used. The organic carboxylic acid may be an aliphatic or aromatic carboxylic acid. Examples of metal salts of organic carboxylic acids include sodium laurate,
Potassium laurate, sodium myristate, potassium myristate, sodium stearate, potassium stearate, sodium ophtacoate, potassium ophtacoate, calcium myristate, calcium stearate, sodium benzoate, potassium benzoate, calcium benzoate, potassium terephthalate , lithium terephthalate, etc. Among these, sodium stearate, sodium benzoate, potassium benzoate, lithium terephthalate, etc. are particularly preferred. These organic carboxylic acid metal salts may be used alone or in combination, and the amount thereof needs to be in the range of 0.06 to 5% by weight based on the resin composition. If the amount is less than 0.03% by weight, excellent heat resistance and appearance improvement effects are hardly exhibited.

Moreover, if it exceeds 5% by weight, the molded product becomes brittle, which is not preferable.

(The hydrocarbon group for the substituent R1 of the epoxy compound (I), which is a DJ acid component, includes an alkyl group, -phenyl group, etc.) These alkyl groups, phenyl groups, etc. may have a halogen atom. .

The monoepoxy compound of formula I preferably has a polyalkylene chain in the molecule because it has a high effect of promoting crystallization. If the molecule does not have a polyalkylene chain, R1 preferably has a long-chain alkyl group with 10 or more carbon atoms, since a small alkyl group at one end lowers the molecular weight of the polyethylene terephthalate.

Examples of the epoxy compound (I) include polyethylene glycol monolauryl monoglycidyl ether, polypropylene glycol monolauryl monoglycidyl ether, polyethylene glycol monostearyl monoglycidyl ether, polyethylene glycol monoceter monoglycidyl ether, polyethylene glycol monooleyl monoglycidyl ether, Polyethylene glycol monophenyl monoglycidyl ether, polyethylene glycol monononylphenyl monoglycidyl ether,
Examples include lauryl glycidyl ether, stearyl glycidyl ether, and cetyl glycidyl ether.

The epoxy compound of formula I may be used alone or in combination, but it is necessary that the epoxy compound is blended in an amount of 0.1 to 10% by weight based on the resin composition. If the amount is less than o, i% by weight, the combined effect of NiH with benzoic acid ester will not be noticeable, and since it is used in combination with benzoic acid ester,
Addition in an amount exceeding 10% by weight is unnecessary and undesirable since the mechanical strength of the molded article decreases. ((To) The benzoic acid ester (■) which is the component is, for example, ethylene glycol dibenzoate, propylene glycol dibenzoate, neopentyl glycol dibenzoate, diethylene glycol 7-lucihey 7" ate, triethylene glycol dibenzoate, etc. can be mentioned.

Benzoic acid ester (n) can be used alone or in combination, but in an amount of 0.1 to 10% by weight based on the resin composition.
If the amount is less than 0.1% by weight, the combined effect with the epoxy compound of formula I will not be noticeable, and since it is used in combination with the epoxy compound, 10% by weight. Addition of larger amounts is unnecessary.

What is important in the polyethylene terephthalate resin composition of the present invention is that components (C), (D), and (E) of the above-mentioned A constituting the composition contain glass fiber-reinforced boron ethylene terephthalate. In particular, by using component (D) in combination with component (g), a high crystallization promoting effect can be obtained with a relatively small amount added.

In addition, the reinforced resin composition of the present invention may optionally contain fillers such as talc, mica, glass groups, clay, and kaolin.
Additives such as light or heat stabilizers, dyes and pigments can be added.

The composition of the present invention comprises a predetermined amount of (A), CB), (C),
It is preferable to melt and knead (D) and ((to) in a suitable kneader such as an extruder and then pelletize it. A molded product can be obtained by subjecting this to injection molding or pressure molding.

Example 1 and Comparative Example 1 A polyethylene terephthalate homopolymer having an intrinsic viscosity [η] of 0.72 had components (C), (J]) and (1Σ) specified in the present invention (comparative examples had (C) and (E)). ) ingredients only)
Additionally, chopped strand glass fibers (hereinafter abbreviated as OF) having a length of 3 were blended in the following proportions and uniformly mixed for 5 minutes in a V-type blender. 65% of this mixture
φ throat vent type melt extrusion, cylinder temperature 26 using extrusion machine
A resin composition was obtained by extrusion at 0 to 290°C and pelletization. Its composition is as follows.

Example 1 Comparative Example 1 Polyethylene terephthalate 64.8% by weight 64
．． 8wt% Gr+' 30
Weight% 60% sodium stearate
0.2% by weight 0.2% by weight Polyethylene glycol (n = 10) Monophenylglycide 6% by weight -
The resulting resin composition was treated with a differential calorimeter (DSC).
The crystallization temperature Tc when the temperature is raised and the crystallization temperature Tc when the temperature is lowered are measured in a nitrogen stream, and △T, which represents the crystallization rate, is measured.
= Tc - Tc was determined. The measurement conditions are 10°C
The temperature was raised at a rate of 10°C/min, held at 280°C for 6 minutes, and then lowered at a rate of 10°C/min. The measurement results are as follows.

As is clear from this result, compared to the benzoate ester alone system, the combination system has a remarkable effect of increasing ΔT,
It was found that the crystallization rate was accelerated.

Examples 2 to 4 and Comparative Examples 2 to 6 (A) or E) components were blended in the proportions shown in the table below,
A resin composition was produced in the same manner as in Example 1. Using this resin composition, the crystallization rate and bending properties were measured. The results are shown in the table below along with Example 1 and Comparative Example 1. The bending strength was measured using a 6oz 6oφ screw set injection molding machine with a cylinder temperature of 260°C, a mold temperature of 80°C, and a molding cycle of 127X12 for 60 seconds.
, 7 x 3.2 rtan strip specimens were molded and AS
The bending test was conducted using TM D790.

Claims (1)

[Scope of Claims] (A) 30 to 85% by weight of polyethylene terephthalate resin, CB) 5 to 60% by weight of glass fiber, (C) Organic carboxylic acid of a metal of group Ⅰ a or group Ⅰ a of the periodic table. Salt 0.
03 to 5% by weight, (D) general formula (in the formula, R□ is a hydrocarbon group or halogenated hydrocarbon group having 6 or more carbon atoms, R2 is an aralkylene group having 2 to 2 carbon atoms, and n is 0 or 1 or more) 0.1 to 10% by weight of an epoxy compound (E) represented by the general formula (in which R is an alkylene group having 2 to 2 carbon atoms, and n is an integer of 1 or more); Ester 0.1-1
A polyethylene terephthalate resin composition comprising 0% by weight (total of each component is 100it%).