JPS60202148A - Polyester resin composition - Google Patents

Abstract

PURPOSE:The titled compsn. with excellent appearance giving a molded product with little shrink mark, which comprises a polyethylene terephthalate resin, glass fiber, a P compd. and a specified polycarbonate resin. CONSTITUTION:30-98.985wt% polyethylene terephthalate resin prepd. by copolymerizing a linear polyethylene terephthalate homopolymer contg. an ethylene terephthalate unit as the constituent unit with a small amt. of a copolymn. component [(iso)phthalic acid], 1-60wt% chopped strand-type glass fiber 0.4-6mm. in length, 0.01-5wt% P compd. such as triphenyl phosphate and 0.005-5wt% at least one polycarbonate resin selected from among resins having at least three average repeating unit of the formula (wherein R1-8 is H or halogen; R9-10 is alkyl) are mixed in a mixer such as a tumbler followed by melt kneading.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a polyester resin composition, and more particularly to a polyester resin composition that produces molded articles with less sink marks and excellent appearance.

[Technical background of the invention and its problems] Glass fiber reinforced polyethylene terephthalate resin has excellent electrical properties, heat resistance, and chemical resistance.

It has been steadily growing due to its economic efficiency.

However, since polyethylene terephthalate resin has a slow crystallization rate, when molded at a mold temperature of 120° C. or lower, the appearance of the molded product is poor and sufficient heat resistance cannot be obtained.

Therefore, the molded product is usually molded at a high temperature of 120° C. or higher, but when molded using a high-temperature mold, sink marks occur in the molded product. In order to prevent the occurrence of sink marks, molding is performed by increasing the pressure holding time or increasing the injection pressure, but it is still not possible to eliminate sink marks on thick parts or on the back side where there are bosses or ribs. There wasn't.

[Object of the Invention] An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a polyester resin composition that produces molded products with less sink marks and has an excellent appearance.

[Summary of the Invention] As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that by blending a specific amount of a specific phosphorus compound and a specific polycarbonate resin into a glass fiber reinforced polyester resin, sink marks can be reduced. The present invention has been completed based on the discovery that this can be prevented.

That is, the polyester resin composition of the present invention includes (A) 30 to 98.985% by weight of polyethylene terephthalate resin (B) 1 to 60% by weight of glass fiber (C) 0.01 to 5% by weight of phosphorus compound (D) The following formula [I
] (In the formula, R2-R8 may be the same or different and each represents a hydrogen atom or a halogen atom,
R9 and R10 may be the same or different and each represents an alkyl group) At least one polycarbonate resin selected from the group consisting of resins having an average repeating unit of 3 or more represented by 0.005 It has been found that this polyester resin composition is characterized by having a polyester resin composition of 5% by weight, and that the foaming phenomenon caused by molding the composition can be utilized to prevent sink marks.

The polyethylene terephthalate resin (component (A)) used in the present invention is a linear polyethylene terephthalate homopolymer having ethylene terephthalate units as a constituent unit, a copolymer obtained by copolymerizing a small amount of a component that can be copolymerized with this, or a copolymer thereof. or mixtures of these homopolymers and copolymers. As the copolymerization component, conventionally known acid components and glycol components can be used.

Here, examples of copolymerization components include acid components such as phthalic acid, isophthalic acid, naphthalene 1,4- or 2,6-dicarboxylic acid, diphenyl ether 4,4°-dicarboxylic acid, adipic acid, and sebacic acid, and propylene glycol. ,
'Butylene glycol, diethylene glycol, neopentyl glycol, cyclohexane dimetatool, 2,
Examples include glycol components such as 2-bis(4°-bitroxyphenyl)propane; oxyacid components such as p-hydroxybenzoic acid and p-hydroxyethoxybenzoic acid.

As component (A), a polymer obtained by either a method of polycondensation via transesterification or a method of polycondensation via direct esterification can be used, but its intrinsic viscosity [η ] is 0.4~
It is desirable that the value is in the range of 1.4, and a polymer with a large [η] can be obtained by further subjecting the polymer obtained by the above-mentioned conventional top-coating method to a known solid-phase method. In addition, [η] is phenol/tetrachloroethane=
50150 (weight ratio) This is a value determined from the solution viscosity measured at 25°C in a solvent.

The blending ratio of component (A) in the resin composition composed of each component (A) to (D) is usually 30 to 98.
It is in the range of 1185% by weight, preferably in the range of 45-80% by weight. If it is less than 30% by weight, flow processability decreases,
! If the amount exceeds 38.985% by weight, the object of the present invention cannot be achieved.

Regarding the glass fibers (component (B)) used in the present invention, the type of glass fibers used and the method of mixing them are not particularly specified, and either roving type or chopped strand type can be used. . Note that, in consideration of productivity, a chopped strand type is preferable. In addition, considering workability during mixing, abrasion of the molding machine, or cutting during the molding process, it is particularly desirable that the m length of the glass fibers at the time of mixing is approximately 0.4 to 8 mm. It is sufficient that the length of the fibers is about 0.2 to 2 cm. As the glass fiber, commercially available products that have been subjected to various treatments may be used as they are.

The blending ratio of this component (B) is usually in the range of 1 to 60% by weight, preferably in the range of 10 to 50% by weight in the resin composition composed of each of the components (A) to (B). .

If the amount exceeds 60% by weight, the molding processability seen from the fluidity processability will be lowered, and if it is less than 1% by weight, the reinforcing effect of the glass fiber will be small, which is not preferable.

Examples of the phosphorus compound (component (C)) used in the present invention include phosphoric acid; trimethyl phosphate, methyl diethyl phosphate, ethyl phosphate, triisopropyl phosphate, tributyl phosphate, and tri-2-ethylhexyl phosphate. , phosphate esters such as tricresyl phosphate, triphenyl phosphate, tribenzyl phosphate, tricyclohexyl phosphate; tinous acid; trimethyl phosphite, triethyl phosphite.

Phosphite esters such as tributyl phosphite, tri(γ-hydroxybutyl) phosphite, and triphenyl phosphite;
Phosphonic acid; Phosphonic acid derivatives such as phenylphosphonic acid, phenyl phenylphosphonate, diphenyl phenylphosphonate, phenyl phosphonate; Phosphinic acid; Phosphinic acid derivatives such as phenylphosph4oic acid, methyl dimethylphosphinate, phenyl methylphosphinate; Examples include phosphine derivatives such as triphenylphosphine; triphenylphosphine oxyto, and one or more selected from the group consisting of these.

The blending ratio of this (component (C)) is usually in the range of 0.01 to 5% by weight, preferably 0.1 to 2% by weight in the resin composition composed of each component (A) to (D). % range. If it is less than 0.01% by weight, foaming will not be sufficient;
If the amount exceeds 20%, the molded product will become brittle, which is not preferable.

The polycarbonate resin (component (D)) used in the present invention is a resin represented by the above-mentioned formula [I], and contains one or two types selected from the group consisting of these resins. used.

In formula [I], the halogen atom is, for example, a chlorine atom,
Examples include bromine atom and iodine atom.

Further, the alkyl group is not particularly limited in the number of carbon atoms, but preferably has 1 to 5 carbon atoms. Furthermore, the average number of repeating units is 3 or more. If the average repeating unit is less than 3, the improvement in preventing sink marks, which is the intended purpose of the present invention, will be insufficient.

The blending ratio of component (D) is in the range of 0.005 to 5% by weight, preferably 0.1 to 2% by weight in the resin composition composed of each component (A) to ([]). range.

If the amount is less than 0.005% by weight, there will be little effect on improving the appearance of molded products such as sink marks, and if the amount exceeds 5% by weight, excessive foaming will occur and the appearance of the molded product will deteriorate, which is not preferable. If necessary,
Furthermore, ultraviolet absorbers, antioxidants, heat deterioration inhibitors, dyes and pigments, flame retardants, matting agents, etc. may be added.

As a method for producing the polyester resin composition of the present invention, 4
There are no particular limitations as long as the method is normally applied to the production of resin compositions. The polycarbonate resin may be added by kneading it together with the three components (A) to (C) at the same time, or by adding the polyester resin consisting of the components (A), (B), and (C) together. A pellet blend with a polyester resin consisting of [l] may also be used. However, in the case of the batch kneading method, it is necessary to extrude at a cylinder temperature of 280° C. or lower in order to suppress foaming within the cylinder of the extruder.

A specific example of preparing the polyester resin composition of the present invention as described above is as follows.

To sufficiently dried polyethylene terephthalate (A),
A predetermined amount of glass fiber (B), phosphorus compound (C), and polycarbonate resin (B) are added, mixed in a suitable mixer such as a tumbler, and then fed to an extruder etc. for melt cross-wire extrusion. and pelletize.

The present invention will be explained in more detail below with reference to Examples and Comparative Examples.

[Embodiments of the Invention] A polyethylene terephthalate homopolymer having [η] of 0.72, various substances of the components (C) and (D) of the present invention, and a three-layer chopped strand glass were added. Fiber #I
(GF) were blended in the proportions shown in Table 1 and uniformly mixed for 5 minutes in a V-type blender. Using a vent type melt extruder with a diameter of 65mm, the mixture was heated at a cylinder temperature of 260~27mm.
The polyester resin compositions of the present invention (Examples 11 to 22) were obtained by extruding and pelletizing at 0°C.

These resin compositions were molded using an 8-ounce screw injection molding machine at a cylinder temperature of 280°C and a mold temperature of 14.
A round bar molded product having a diameter of 33 1φ x 7h was obtained at 0° C. and a molding cycle of 3 minutes.

The shrinkage of this molded product was measured by the expansion ratio using the method described below. In addition, sink marks and surface appearance of the molded products were visually observed. The results are shown in the table.

6-1 The above-described round bars of 33 mmφ×70 cm were molded under various conditions, and the expansion ratio was calculated using the following formula.

The larger the foaming ratio, the fewer sink marks.

Here, the specific gravity of the blank refers to the specific gravity of a molded product to which components (C) and (D) are not added.

GF;l'7ヱL1j 150% by weight 1.42 30% by weight 1.53 50% by weight 1.88 Sai1旌J2'' As shown in the table, except for changing the composition and blending ratio, the rest was carried out. Compositions (Comparative Examples 1 to 4) were obtained in the same manner as in the example.

The obtained compositions were subjected to the same measurements and observations as in the examples. The results are shown in the table.

[Effects of the Invention] As described in detail above, the polyester resin composition of the present invention produces molded articles with less sink marks and excellent appearance, and has extremely high industrial value.

Procedural amendment July 2, 1980 Mr. Manabu Shiga, Commissioner of the Patent Office■, Indication of the case Patent Application No. 57364 of 1982 2 Name of the invention Polyester resin composition 3, Person making the amendment Relationship to the case Patent Name of applicant (30?) Mitsubishi Rayon Co., Ltd. 4 Address of agent 2-10-85 Akasaka, Minato-ku, Tokyo 107 Date of amendment order Voluntary 6 Number of inventions increased by amendment None 7 Subject of amendment Details Column 8 of Detailed Description of the Invention of the Book, Contents of Amendment (1) “150% by weight” stated in page 12, line 10 of the specification.
” is corrected to “r15% by weight”.

(2) "Ratio of molded product" written in the upper right column of the table on page 13 will be corrected to "specific gravity of molded product" and "Appearance of statement" will be corrected to "surface appearance."

Claims (1)

[Claims] (A) Polyethylene terephthalate resin 30-98.
985% by weight (B) Glass fiber 1-60% by weight (C) Phosphorus compound 0.0.1-5% by weight (D) Following formula [
11 (wherein R and -R8 may be the same or different and each represents a hydrogen atom or a halogen atom,
R9 and R10 may be the same or different and each represents an alkyl group) At least one poly-303 carbonate resin selected from the group consisting of resins having three or more average repeating units represented by A polyester resin composition comprising 0.005 to 5% by weight.