JPH06179803A - Poly@(3754/24)ethylene terephthalate) resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition which is excellent in mechanical properties, flowability, and releasability and gives a molding excellent in appearance and having diminished burrs by incorporating an inorganic filler, a poly (ethylene glycol) blocked at each end, talc, and a metal salt of a fatty acid into poly (ethylene terephthalate). CONSTITUTION:The resin composition comprises 20-80wt.% poly (ethylene terephthalate), up to 60wt.% inorganic filler, 1.0-10wt.% poly (ethylene glycol) blocked at each end in which 80% or more of the hydrogen atoms of the terminal hydroxyl groups have been replaced with methyl groups and which has a weight-average mol.wt. of 700-5,000, 0.5-5wt.% talc having an average particle diameter of 1-10mum, and 0.1-1wt.% metal salt of a fatty acid. For imparting flame retardancy to the composition, 2-25wt.% brominated polystyrene (flame retardant) and 1-10wt.% sodium antimonate (flame retardant aid) are further added.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyethylene terephthalate resin composition. More specifically, the present invention relates to a well-balanced resin composition which is excellent in mechanical strength, appearance, fluidity and releasability, is flame retardant if necessary, and has less burrs.

[0002]

2. Description of the Related Art Conventionally, polyethylene terephthalate has taken advantage of its excellent heat resistance and mechanical properties, and has made use of its excellent heat resistance and mechanical properties.
Widely used for materials such as relay cases and transformers. However, polyethylene terephthalate has a slow crystallization rate, and it was difficult to mold it with a mold of about 110 ° C. or lower. Therefore, when injection molding was performed, burrs were generated on the molded product. Recently, it has become possible to accelerate the crystallization rate of polyethylene terephthalate with various crystallization accelerators, plasticizers, nucleating agents, etc., but it is less effective in controlling and preventing burrs.

Further, it is possible to use a large amount of glass fibers for the prevention of burrs, but this method has a problem that the fluidity of the composition obtained is lowered and the appearance is deteriorated. However, recently, with the miniaturization and thinning of electronic parts such as switches, connectors, and relay cases, the characteristics required for resins have become more severe, and not only excellent mechanical and electrical characteristics but also high fluidity and high separation It has been desired to develop a polyethylene terephthalate resin composition having moldability and low flash property.

[0004]

The present invention has reached the present invention as a result of extensive studies to obtain a resin composition having excellent mechanical properties, fluidity, releasability, and appearance, and having less burr.

That is, the polyethylene terephthalate resin composition of the present invention is (A) polyethylene terephthalate 20.
To 80% by weight (in the entire composition), (B) 60% by weight or less (in the entire composition) of the inorganic filler, and (C) 80% or more of the hydrogen at both terminal hydroxyl groups are replaced by methyl groups. Is 700 to 5000 and polyethylene glycol having both ends blocked 1.0 to 10% by weight (in the entire composition), (D) average particle size 1
0.5 to 5% by weight of talc of 10 μm (in the total composition) and 0.1 to 1% by weight (E) of a metal salt of an aliphatic monocarboxylic acid (in the total composition).

Furthermore, the present invention includes a composition which has been subjected to a flame-retardant treatment, wherein (A) polyethylene terephthalate 20 to 80% by weight (in the total composition), (B) 60% by weight or less (total composition). (In the product), (C) both ends hydroxyl groups of hydrogen having 80% or more hydrogen substituted at both ends by a methyl group and a weight average molecular weight of 700 to 5000 both ends blocked polyethylene glycol 1.0 to 10% by weight (total composition Medium), (D) 0.5 to 5% by weight of talc having an average particle size of 1 to 10 μm (in the entire composition), (E) Metal salt of aliphatic monocarboxylic acid 0.1 to 1
In addition to the composition by weight (in the total composition), a flame retardant of the following (F) component and a flame retardant auxiliary of the (G) component are included, and specifically, (F) brominated It is composed of 2 to 25% by weight of polystyrene (in the whole composition) and 1 to 10% by weight of (G) sodium antimonate (in the whole composition).

The resin composition of the present invention will be described in detail below.

First, (A) polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") used in the present invention comprises, for example, a dicarboxylic acid having at least 90 mol% terephthalic acid or an ester-forming derivative component thereof. It is a polymer obtained by subjecting a glycol component of which at least 90 mol% is ethylene glycol to an esterification reaction or a transesterification reaction, and then to a polycondensation reaction. As the ester-forming derivative of dicarboxylic acid,
Examples thereof include dialkyl esters and diaryl esters of terephthalic acid.

Further, as glycols which can be used together in the range of 10 mol% or less with respect to ethylene glycol as a glycol component, propylene glycol, butylene glycol, neopentyl glycol, cyclohexanedimethanol, 2,2-bis (4- Mention may be made of glycols such as hydroxyphenyl) propane.

The degree of polymerization of polyethylene terephthalate used in the present invention is not particularly limited, but the intrinsic viscosity (at 35 ° C. in orthochlorophenol) is 0.3 to.
A value of 1.0 is preferable. In the polyethylene terephthalate resin composition of the present invention, the polyethylene terephthalate accounts for 20 to 80% by weight of the total composition.
If the amount of polyethylene terephthalate is less than 20% by weight, the moldability becomes difficult, while if it exceeds 80% by weight, the mechanical strength of the molded product becomes problematic.

Next, in the present invention, the inorganic filler (B) is blended in order to obtain a molded article having excellent properties such as mechanical strength, heat resistance and dimensional stability.

As the inorganic filler (B), glass fiber,
Fibrous fillers such as graphite fiber, aramid fiber, silica fiber and alumina fiber, powdered and granular fillers such as carbon black, silica, glass beads, calcium silicate, whiskers, kaolin and wollastonite, mica, glass flakes It is possible to use a plate-like filler such as These inorganic fillers can be used alone or in combination of two or more.

In using these inorganic fillers,
If necessary, it is desirable to use a sizing agent or a surface treatment agent together. Examples of this are functional compounds such as epoxy compounds, isocyanate compounds, silane compounds and titanate compounds. These compounds may be used by subjecting the inorganic filler to a surface treatment or a converging treatment in advance, or may be added at the same time when the material is adjusted.

In the present invention, the content of the inorganic filler (B) is 60% by weight or less, preferably 5 to 50% by weight. When the content of the inorganic filler exceeds 60% by weight, the molding process becomes difficult and the mechanical strength of the molded product also becomes problematic. The amount of the functional surface treating agent used in combination is 0.05 to 10% by weight, preferably 1 to 5% by weight, based on the inorganic filler.

Further, the component (C) used in the present invention, which is a polyoxyethylene glycol capped with methyl groups at both ends, is compounded to function as a plasticizer. Since polyoxyethylene glycol with both ends methylated is not reactive, it is uniformly dispersed in polyester when blended with PET. This polyoxyethylene glycol improves the mobility of the molecular chain more than PET, and exhibits a crystallization promoting effect. The weight-average molecular weight of the polyoxyethylene glycol with both ends methyl group blocked is 700 to 5,000.
And the range of 800 to 4000 is more preferable. When the weight average molecular weight is less than 700, the heat loss of the molded product obtained from the resin composition containing polyoxyethylene glycol is large. Also, the weight average molecular weight is 5
If the polyoxyethylene glycol content exceeds 000, the plasticizing effect of the obtained resin composition becomes excessive, and the mechanical strength of the molded product decreases.

Further, the methyl group blocking rate of hydrogen at both end hydroxyl groups is 80% or more, more preferably 90% or more. When the blocking rate of both end methyl groups is less than 80%, it has reactivity, reacts with PET, is not uniformly dispersed, and has a small plasticizing effect. The compounding amount of polyethylene glycol with both ends methyl group blocked is 1 to 12% by weight (in the total composition), and more preferably 1 to 10% by weight (in the total composition). If the content is less than 1% by weight, the effect of promoting crystallization is small. Further, if the blending amount exceeds 12% by weight, the mechanical properties of the obtained molded product will be extremely deteriorated.

The talc of the component (D) of the present invention is blended as a crystal nucleating agent. The average particle size of talc is 1 to 10 μm. When it is less than 1 μm, the mechanical strength of the obtained molded article is lowered, and when it exceeds 10 μm, the effect as a crystal nucleating agent is lowered, which is not preferable. The blending amount of talc is 0.5 to 5% by weight
(In the entire composition). If the content is less than 0.5% by weight, crystallization of the obtained molded product is slow, and if it exceeds 5% by weight, mechanical strength is lowered, which is not preferable.

In addition, the metal salt of the aliphatic monocarboxylic acid as the component (E) used in the present invention is known as a crystal nucleating agent, but is compounded in the present invention for the purpose of functioning as a releasing agent for another purpose. To do. As a specific example, Na palmitate,
Examples include Ca stearate, Zn behenate, and Na montanate, with Na palmitate being preferred.
The compounding amount of the metal salt of the aliphatic monocarboxylic acid is 0.1 to 1.
It is 0% by weight. If the content is less than 0.1% by weight, the mold release during molding is poor, and if it exceeds 1.0% by weight, the thermal stability of the obtained resin composition is impaired.

The flame-retardant resin composition according to one aspect of the present invention comprises the components (A) to (E), the component (F) and the component (G), and the flame retardant auxiliary. Is compounded.

That is, the brominated polystyrene as the component (F) is blended to bring about a flame retardant effect.

Brominated flame retardants other than brominated polystyrene,
For example, a flame retardant effect can be obtained by using brominated epoxy or brominated polycarbonate. However, the addition of the flame retardant increases the melt viscosity of the composition and impairs the fluidity. As the brominated polystyrene, one or two kinds can be selected from dibromopolystyrene and tribromopolystyrene, and the manufacturing method thereof is not particularly limited. The blending amount of brominated polystyrene is 2 to 25% by weight (in the entire composition), more preferably 5 to 20% by weight. If the blending amount is less than 2% by weight, the flame-retardant effect of the obtained molded article cannot be obtained, and if it exceeds 25% by weight, the mechanical strength decreases, which is not preferable.

In addition, the component (G), sodium antimonate, is preferably used in combination with the brominated polystyrene (E) in order to improve the flame retardant effect as a flame retardant aid. If an antimony-based flame retardant aid other than sodium antimonate, such as antimony trioxide, antimony tetroxide or antimony pentoxide, is used, the effect as a flame retardant aid can be obtained. However, decomposition and degradation of PET and decomposition of the flame retardant occur, which causes deterioration of mechanical strength of molded products, deterioration of aesthetics, deterioration of thermal stability, generation of decomposition gas, and the like. The content of sodium antimonate is 1 to 10% by weight (in the whole composition), and more preferably 2 to 8% by weight. If the blending amount is too large, the decomposition of the resin or the compounding agent is promoted to lower the mechanical strength, and if it is too small, the flame retardancy cannot be obtained, which is not preferable.

The polyethylene terephthalate resin composition of the present invention further comprises known additives such as a lubricant, a nucleating agent, a release agent, an antistatic agent other than the above-mentioned components in order to impart desired properties according to the purpose. Agent, surfactant, plasticizer,
It is of course possible to add a colorant, a heat stabilizer or an ultraviolet stabilizer.

The polyethylene terephthalate resin composition of the present invention can be easily prepared by known equipment and methods generally used as conventional resin composition preparation methods. For example, 1) a method in which each component is mixed, then kneaded and extruded by an extruder to adjust pellets, and then molded, 2) pellets having different compositions are once adjusted, and a predetermined amount of the pellets are mixed and molded, and molded Any method such as a method of obtaining a molded article having a desired composition later, a method of directly charging one or more of each component into a molding machine, and the like can be adopted. In addition, it is a preferable method to form a fine powder of a part of the resin component and mix it with the other components to reduce the amount thereof, in order to uniformly mix these components.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples.

The measuring method for the characteristic evaluation shown in the examples is as follows.

1) Physical property measuring method Tensile test According to ASTM D638. Izod impact strength According to ASTM D 256.

2) Method of measuring fluidity Using a test die for measuring rod flow length (cavity: width 10 mm x thickness 0.7 mm), molding was performed under the following conditions, and the flow length (molded product length) Was evaluated for liquidity.

Molding condition: Cylinder temperature: 280 ° C. Injection pressure: 100 kg / cm ² Mold temperature: 80 ° C. 3) Burr evaluation A molded product with a bar flow length of 0.05 mm is considered as a burr and a thickness of 0.5 mm bar. The Bali index was calculated by comparing with the flow length.
Molding conditions are cylinder temperature 280 ℃, mold temperature 80
℃, injection pressure 400kg / cm ² , injection speed 100mm / se
c. The lower the index, the less burr.

[0030]

[Equation 1]

4) Retention test in molding machine (thermal stability) The sample was retained in the molding machine cylinder at a cylinder temperature of 280 ° C. for 30 minutes and then molded, and the tensile strength of the molded test piece was measured to determine the thermal stability. , Evaluate the degree of deterioration.

5) Visual inspection of molded product A disk (100 mm diameter, 3 mm thickness) is molded and observed with reference to the presence or absence of differently colored spots and the degree thereof, and judgment is made according to the following ranks.

Spots ○: No △: Little Yes ×: Many 6) Crystallization temperature measurement method The crystallization temperature was measured by a differential calorimeter using a sample obtained by performing melting and quenching operations in advance and using a nitrogen stream. Inside
The temperature is raised at a rate of 10 ° C./min, and the crystallization temperature during temperature rise is measured. The smaller the value of the crystallization temperature, the easier the crystallization.

7) Heat loss measurement method A disk (50 mm diameter, thickness 5 mm) is molded and determined by the following formula.

W ₀ : Weight after 1 hr after molding (g) W ₁ : Weight after heating at 185 ° C. for 10 days (g)

[0036]

[Equation 2]

8) Method of evaluating mold releasability A molded product with a cylindrical top and bottom (outer diameter 40 mmφ, height 40 mm, average wall thickness 5 mm) is molded to obtain a molded product with a good appearance without losing the mold shape. Obtain the release force (load force applied to the ejection pin) (kg ・ cm) under the following conditions.
The lower the value, the better the releasability.

Molding conditions: Cylinder temperature: 280 ° C. Injection pressure: 1200 kg / cm ² Mold temperature: 80 ° C. 9) Bromine generation evaluation 300 ° C. A cylindrical glass container was installed in the flow path of heated air and resin was sealed. Immerse in an oil bath at 300 ° C. The circulating air is introduced into pure water, and the generated bromine is converted to HB.
Collect as r for 1 hour. HBr generation weight ppm with respect to the encapsulating resin in this aqueous solution using an ion chromatograph
To measure.

10) Combustion test (UL-94) Subject 9 of Underwriters Laboratories
According to the method of 4 (UL-94), 5 test pieces (thickness:
Test for flammability using 1/32 inch).

[0040]

Examples 1 to 10 and Comparative Examples 1 to 9 Intrinsic viscosity (35
C., in ortho-chlorophenol) 0.7 polyethylene terephthalate with various ingredients shown in Tables 1 and 2
After adding and mixing the amount shown in (1), a pelletized composition was prepared using an extruder. Next, various test pieces were prepared by using the pellets or by injection molding from the pellets, and the above evaluation was performed. The results are shown in Tables 1 and 2.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

Examples 11 to 20 and Comparative Examples 11 to 27 Polyethylene terephthalate having an intrinsic viscosity of 0.7 was added with various components shown in Tables 3 to 6 in the amounts shown in Tables 3 to 6 and mixed. A pelletized composition was prepared by an extruder. Next, various test pieces were prepared by using the pellets or by injection-molding the pellets, and various evaluations were performed. The results are shown in Tables 3 to 6.

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Table 6]

[0048]

The resin composition of the present invention has a function in which the following characteristics are effectively improved. 1) Excellent mechanical properties such as tensile properties and Izod impact strength. 2) High fluidity. 3) Less burr is generated. 4) Due to its excellent thermal stability, less decomposition volatile gas is generated. 5) No generation of differently colored spots on the molded product. 6) Easy crystallinity. 7) Little heat loss after high temperature heat treatment. 8) The mold release is excellent and the molded product can be easily removed from the mold.

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Claims (4)

[Claims] 1. (A) Polyethylene terephthalate 20
To 80% by weight (in the entire composition), (B) 60% by weight or less (in the entire composition) of the inorganic filler, and (C) 80% or more of the hydrogen at both terminal hydroxyl groups are replaced by methyl groups. Is 700 to 5000 and polyethylene glycol having both ends blocked 1.0 to 10% by weight (in the entire composition), (D) average particle size 1
A polyethylene terephthalate resin composition comprising 0.5 to 5% by weight of talc of 10 μm (in the total composition) and (E) 0.1 to 1% by weight of a metal salt of an aliphatic monocarboxylic acid (in the total composition). 2. (A) Polyethylene terephthalate 20
To 80% by weight (in the entire composition), (B) 60% by weight or less (in the entire composition) of the inorganic filler, and (C) 80% or more of the hydrogen at both terminal hydroxyl groups are replaced by methyl groups. Is 700 to 5000 and polyethylene glycol having both ends blocked 1.0 to 10% by weight (in the entire composition), (D) average particle size 1
0.5 to 5% by weight of talc of 10 μm (in the entire composition),
(E) 0.1 to 1% by weight of metal salt of aliphatic monocarboxylic acid
A polyethylene terephthalate resin composition comprising (in the whole composition), (F) brominated polystyrene 2 to 25% by weight (in the whole composition) and (G) sodium antimonate 1 to 10% by weight (in the whole composition). 3. The polyethylene terephthalate resin composition according to claim 1, wherein the aliphatic monocarboxylic acid as the component (E) is any one of palmitic acid, stearic acid, behenic acid and montanic acid. 4. The polyethylene terephthalate resin composition according to claim 1, wherein the metal salt of component (E) is a metal salt of Group I or Group II of the periodic table.