JPH05140428A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the subject compsn. excellent in the balance among stiffness, strengths, heat resistance, and impact resistance. CONSTITUTION:The objective compsn. comprises 50-95wt.% polyester, 1-40wt.% thermoplastic styrenic elastomer modified with an unsatd. glycidyl compd., and 4-45wt.% inorg. filler.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester resin composition. More specifically, the present invention relates to a polyester resin composition which is excellent in rigidity, strength, heat resistance and impact resistance and is suitable for molded articles such as automobile interior / exterior parts, electrical components and home electric appliances.

[0002]

2. Description of the Related Art Polyester has heat resistance,
It is a resin that has excellent mechanical strength and insulation properties, and it is widely used mainly in electrical components due to its characteristics. However, polyester has a low impact strength, and therefore, there is a problem in using it in applications requiring impact resistance in addition to the above properties. Therefore, if a thermoplastic elastomer is added to the polyester in order to improve the impact resistance of the polyester, the impact strength is increased, but on the contrary, the characteristics of the polyester such as rigidity, strength and heat resistance are greatly reduced.
When an inorganic filler is added, rigidity, strength and heat resistance are increased, but impact strength is greatly reduced. Therefore,
An object of the present invention is to provide a polyester resin composition having a good balance of rigidity, strength, heat resistance and impact strength.

[0003]

Means for Solving the Problems As a result of intensive studies made by the present inventors, when a styrene-based thermoplastic elastomer modified with an unsaturated glycidyl compound and an inorganic filler were blended in a specific ratio to the polyester, the rigidity was improved. The present invention has been accomplished by finding that a polyester resin composition having improved strength, heat resistance and impact strength can be obtained. That is, the present invention comprises (a) a polyester, (b) a styrene-based thermoplastic elastomer modified with an unsaturated glycidyl compound, and (c) an inorganic filler, and comprises the components (a) and (b). And the ratio of (c) is (a)
50-95% by weight, (b) 1-40% by weight and (c)
The polyester resin composition is 4 to 45% by weight.

The polyester resin composition of the present invention will be described in detail below. The (a) polyester of the polyester resin composition component of the present invention is a thermoplastic resin generally obtained by polycondensation of a saturated dicarboxylic acid and a saturated dihydric alcohol, and includes, for example, polyethylene terephthalate, polypropylene terephthalate, polytetramethylene terephthalate (polyester). Butylene terephthalate), polyhexamethylene terephthalate, polycyclohexane-1,4-dimethylol terephthalate, polyneopentyl terephthalate and the like. Of these, polyethylene terephthalate and polybutylene terephthalate are preferred.

The polyester as the above component (a) is
The intrinsic viscosity [η] (dl / g) obtained from the solution viscosity measured at 25 ° C in an o-chlorophenol solvent is 0.30 to 1.
It is preferable that the terminal carboxyl group has a terminal carboxyl group concentration of 10 to 200 meq / kg. In the case of polyethylene terephthalate, it is preferable that the intrinsic viscosity [η] is 0.30 to 1.2 and the terminal carboxyl group concentration is 10 to 200 meq / kg.
The terephthalic acid component in polyethylene terephthalate may be substituted with an alkyl group, a halogen group or the like, and the glycol component may be up to about 50% by weight of another glycol such as 1,4-, in addition to ethylene glycol.
It may contain butylene glycol, propylene glycol, hexamethylene glycol and the like. In the case of polybutylene terephthalate, the intrinsic viscosity [η] is 0.30
Preferably, the terminal carboxyl group concentration is 10 to 200 meq / kg. Also in this case, the terephthalic acid component may be substituted with an alkyl group, a halogen group or the like, and the glycol component may be 1,4-butylene glycol or another glycol such as ethylene glycol or propylene glycol up to about 50% by weight. Hexamethylene glycol and the like may be contained.

(B) of the polyester resin composition of the present invention
The styrene-based thermoplastic elastomer modified with the unsaturated glycidyl compound in the component, a styrene-based monomer, random with other monomers such as monoolefin or diolefin copolymerizable with the styrene-based monomer,
They are copolymers such as blocks and grafts, and hydrogenated products of these copolymers.

Here, as the styrene-based monomer, styrene, α-chlorostyrene, 2,4-dichlorostyrene, p-methoxystyrene, p-methylstyrene, p-
Phenylstyrene, p-divinylbenzene, p- (chloromethoxy) -styrene, α-methylstyrene, o-methyl-α-methylstyrene, m-methyl-α-methylstyrene, p-methyl-α-methylstyrene, p -Methoxy-α-methylstyrene and the like can be mentioned. Of these, styrene is preferably used.

Examples of the diolefin which is copolymerized with the styrene-based monomer to form a styrene-based thermoplastic elastomer include non-conjugated dienes such as dicyclopentadiene, 1,4-hexadiene, cyclooctadiene and methylnorbornene, or butadiene. And conjugated dienes such as isoprene. Of these, butadiene and isoprene are preferred. Further, as the mono-olefin, in addition to ethylene, propylene, butene-1, hexene-1,
Examples thereof include α-olefins having 3 or more carbon atoms such as 3-methylbutene-1, 4-methyl-pentene-1, heptene-1, octene-1, and decene-1, and of these, ethylene and propylene are preferable.

The styrene-based thermoplastic elastomer used as the raw material elastomer of the modified styrene-based thermoplastic elastomer in the component (b) of the present invention can be prepared by using the above-mentioned suitable monomer by a known suitable method such as anionic polymerization or radical polymerization. It can be obtained by copolymerization. Specific examples of preferable raw material elastomers include styrene-butadiene-styrene block copolymer (SBS) and its hydrogenated product styrene-ethylene-butylene-styrene block copolymer (SEBS).
Styrene-butadiene copolymer (SB) and hydrogenated product thereof, styrene-ethylene-butylene block copolymer (SEB), styrene-isoprene copolymer (SI) and hydrogenated product thereof, styrene-ethylene-propylene block copolymer Examples thereof include a polymer (SEP), a styrene-isoprene-styrene block copolymer (SIS), and a hydrogenated product thereof, a styrene-ethylene-propylene-styrene block copolymer (SEPS).
BS and SEPS are particularly preferred.

The above raw material elastomer preferably has a styrene-based monomer content of 5 to 65% by weight, particularly 1
It is preferably 5 to 50% by weight. As such a preferable raw material styrene-based thermoplastic elastomer, a commercially available product can be appropriately selected and used.

The component (b) of the polyester resin composition of the present invention is the above-mentioned various styrene-based thermoplastic elastomers modified with an unsaturated glycidyl compound. Here, examples of the unsaturated glycidyl compound used as the modifier include a glycidyl compound having an unsaturated group capable of copolymerizing with an olefin and a glycidyloxy group in the molecule. Specific examples thereof include unsaturated carboxylic acid glycidyl esters and unsaturated glycidyl ethers, and unsaturated carboxylic acid glycidyl esters are preferably used. Examples of the unsaturated carboxylic acid glycidyl ester include glycidyl esters of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, tiglic acid, and angelic acid, among which glycidyl acrylate (GA) and glycidyl methacrylate. (GMA) is preferred.

The modified thermoplastic elastomer preferred in the present invention is the above-mentioned raw material styrene-based thermoplastic elastomer, among which SEBS or SEPS is modified with the glycidyl compound. The content of the unsaturated glycidyl compound as a modifier of the modified styrene-based thermoplastic elastomer varies depending on the kind of the raw material styrene-based thermoplastic elastomer and cannot be generally stated, but it is generally about 0.2 to 5% by weight, preferably 0.5. ~ 3% by weight.

Such a modified styrenic thermoplastic elastomer can be obtained by utilizing a known modification method such as a solution method or a melt-kneading method. In addition, a commercially available product may be appropriately selected and used. As a specific example of the modification method, an example of modification of SEBS with GMA (graft polymerization) is shown below. That is, in the melt-kneading method, SEB
Using S and GMA and, if necessary, a catalyst, and introducing these components into an extruder, a twin-screw kneader, or the like, 170 to 300 ° C
The modified SEBS is obtained by kneading for about 0.1 to 20 minutes while heating to a temperature of about 3 to melt. In the case of the solution method,
90% by dissolving the above starting materials in an organic solvent such as xylene.
Denaturation is carried out at a temperature of about 200 ° C. for 0.1 to 100 hours with stirring.

In any of the modification methods, an ordinary radical polymerization catalyst is used as a catalyst to modify the glycidyl compound 10.
About 0.1 to 10 parts by weight can be used with respect to 0 parts by weight. For example, benzoyl peroxide, lauroyl peroxide, di-t-butyl peroxide, acetyl peroxide, t-perbenzoate.
Butyl, dicumyl peroxide, perbenzoic acid, peracetic acid, t-butyl perpivalate, 2,5-dimethyl-2,5-di-t
-Peroxides such as butylperoxyhexyne and diazo compounds such as azobisisobutyronitrile are used. In addition, it is also possible to add a phenol type antioxidant and a phosphorus type antioxidant during the above graft reaction.

The modified styrenic thermoplastic elastomer thus obtained has a graft ratio of about 0.2 to 5% by weight and a melt flow rate (MFR, JISK7210, load 2.16 kg, 230 ° C.) of about 0.1 to 100 g / 10 min. Then
It is preferably used in the present invention.

Further, in the present invention, (c) an inorganic filler is blended in order to improve the rigidity, strength and heat resistance of polyester. Examples of the inorganic filler include oxides such as alumina, magnesium oxide and calcium oxide, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, calcium hydroxide, tin oxide hydrate and zirconium oxide hydrate. Hydrated metal oxides, carbonates such as calcium carbonate, magnesium carbonate, silicates such as talc, clay, bentonite, barium borate, borate such as zinc borate, aluminum phosphate, sodium tripolyphosphate, etc. Sulfate of phosphate, barium, gypsum etc.,
Metal powder such as sulfite, copper, iron, lead, wollastonite,
Examples thereof include mica and a mixture of two or more thereof.
These inorganic fillers can be used in various shapes such as powder, sphere and flake.

Among the above inorganic fillers, talc, barium sulfate, calcium carbonate, wollastonite and mica are preferable, and talc, calcium carbonate and mica are particularly preferable. Here, talc is a complex salt of magnesium oxide and silicic acid, and has an average particle size of 0.1 to 100 μm.
The average particle size of calcium carbonate is preferably about m.
It is preferably about 0.1 to 30 μm. Mica is an aluminosilicate containing an alkali metal and has an average particle size of about 5 to 500 μm and an aspect ratio of 10 to 5.
It is preferably about 00.

The components (a), (b) and (c) are blended in such a proportion that the component (a) is 50 to 95% by weight, preferably 60 to 90% by weight, and the component (b) is 1 to 40% by weight. , Preferably 3 to 20% by weight, the component (c) is 4 to 45% by weight,
It is preferably 5 to 30% by weight. When the amount of the component (a) is less than 50% by weight, the amount of the polyester is too small, and when the amount is more than 95% by weight, the effect of improving the physical properties of the polyester by the components (b) and (c) cannot be recognized.

Other crystalline polyolefins and polyolefin elastomers (1 to 20% by weight based on the total polyester composition) may be added to the extent that the characteristics of the polyester resin composition of the present invention are not impaired. Here, the olefin elastomer means a copolymer rubber of two or more kinds of α-olefins such as ethylene, propylene, butene-1, hexene-1, and 4-methyl-pentene-1,
It also means a copolymer of α-olefin and another type of monomer. Specific examples of the copolymer rubber of two or more kinds of α-olefins include ethylene-propylene rubber (EPR), ethylene-butene rubber (EBR) and ethylene-propylene-diene rubber (EPDM). In the present invention, in addition to the above-mentioned substances, for the purpose of further modification thereof, other fillers and reinforcing materials usually used in the field of resin compositions, heat stabilizers, light stabilizers,
A flame retardant, a plasticizer, an antistatic agent, a foaming agent, a nucleating agent and the like can be appropriately added.

The polyester resin composition of the present invention is prepared by mixing the above components with a kneading machine such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneading roll, and a Brabender.
It can be obtained by heating, melting and kneading at 0 to 320 ° C, preferably 250 to 280 ° C. In the present invention, the kneading order of each component is not particularly limited, and the components (a), (b) and (c) may be kneaded together, or after kneading the components (a) and (b), The component (c) may be kneaded, and other kneading orders may be adopted.

[0021]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. In each of the examples and comparative examples, the following materials were used as raw materials and additives. Polyester polybutylene terephthalate PBT: [TRB-J manufactured by Teijin Limited, intrinsic viscosity [η] 0.87
(In o-chlorophenol)] Styrene-based thermoplastic elastomer SEBS: [Asahi Kasei Corporation, Tuftec H-1041,
Styrene content 30% by weight, melt flow rate (MF
R, 190 ° C, 2.16 kg load) 5.0 g / 10 minutes]

Modified styrene thermoplastic elastomer modified SEBS: SEBS [manufactured by Asahi Kasei Corporation, Tuftec H-1041, styrene content 30% by weight, melt flow rate (MFR, 190 ° C., 2.16 kg load) 5.0 g / 10
Min] 100 parts by weight, GMA1.5 parts by weight and catalyst (Perhexin 25B: manufactured by NOF CORPORATION) 0.03 parts by weight are dry blended, and then this is blended at 200 ° C. and 100 rpm using a uniaxial extruder having a diameter of 65 mm. Melt kneading was carried out under the conditions to obtain GMA-modified SEBS having a melt flow rate (MFR, 230 ° C., 2.16 kg load) of 5 g / 10 min. The GMA graft ratio of this modified styrene-based thermoplastic elastomer was 1% by weight.

Inorganic filler talc: [Fuji Talc Co., Ltd., LMS 300, average particle size 1.2 μm] Calcium carbonate: [Shiraishi Industry Co., Ltd., Whiten P-30] Mica: [Kuraray Co., Ltd., 200HK, Average flakes 90 μm]

Examples 1 to 4 and Comparative Examples 1 to 3 Polyester (PBT), GMA modified SEBS (modified SEBS) or unmodified SEBS, and inorganic filler (or) in the ratio shown in Table 1. After dry blending with a Henschel mixer, use a twin-screw extruder (L / D = 28) with a diameter of 45 mm, 250 ° C., 200 rp
The resin composition was pelletized by kneading at m 2. The polyester resin composition thus obtained is injection-molded, the flexural modulus of the molded product, the tensile yield strength, the tensile elongation at break,
The heat distortion temperature and Izod impact strength were measured. The results are also shown in Table 1.

[0025]

[Table 1]

The methods for measuring the physical properties shown in Table 1 above are as follows. (1) Flexural modulus (23 ° C.): measured by ASTM D-790. (2) Tensile yield strength (23 ° C): measured by ASTM D-638. (3) Tensile elongation at break (23 ° C): measured by ASTM D-638. (4) Heat distortion temperature (load 4.6 kg / cm ² ): Measured by ASTM D-648. (5) Izod impact strength (23 ℃ and -20 ℃): AS
Measured with TM D-256.

As is apparent from Table 1, the composition of the present invention containing polyester, GMA-modified SEBS, talc, calcium carbonate or mica (Examples 1 to 4).
Is a composition comprising polyester and GMA-modified SEBS (Comparative Example 1), polyester and inorganic filler (talc)
Flexural modulus, tensile yield strength, and a composition (Comparative Example 2) composed of and a composition (Comparative Example 3) composed of polyester, unmodified SEBS, and inorganic filler (talc),
It has an excellent balance of tensile elongation at break, heat distortion temperature, and Izod impact strength, and the improvement of Izod impact strength is remarkable.

[0028]

As described in detail above, the polyester resin composition of the present invention is made by blending polyester with a modified styrene thermoplastic elastomer and an inorganic filler, and has rigidity, strength and heat resistance. And a resin composition having an excellent balance of impact resistance. Such a polyester resin composition of the present invention is suitable as various engineering plastics, particularly as a resin composition for interior and exterior parts of automobiles, home electric appliance parts and the like.

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[Procedure amendment]

[Submission date] November 28, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

Examples 1 to 6 and Comparative Examples 1 to 3 Polyester (PBT), GMA modified SEBS (modified SEBS) or unmodified SEBS, and inorganic filler (or) in the proportions shown in Table 1. After dry blending with a Henschel mixer, use a twin-screw extruder (L / D = 28) with a diameter of 45 mm at 250 ° C. and 200
The resin composition was kneaded at rpm to obtain pellets of the resin composition. The polyester resin composition thus obtained was injection molded, and the flexural modulus, tensile yield strength, tensile elongation at break, heat distortion temperature and Izod impact strength of the molded product were measured. The results are also shown in Table 1.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

[Table 1]

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

As is clear from Table 1, the composition of the present invention containing polyester, GMA-modified SEBS, talc, calcium carbonate or mica (Examples 1 to 6 )
Is a composition comprising polyester and GMA-modified SEBS (Comparative Example 1), polyester and inorganic filler (talc)
Flexural modulus, tensile yield strength, and a composition (Comparative Example 2) composed of and a composition (Comparative Example 3) composed of polyester, unmodified SEBS, and inorganic filler (talc),
It has an excellent balance of tensile elongation at break, heat distortion temperature, and Izod impact strength, and the improvement of Izod impact strength is remarkable.

Claims (1)

[Claims] 1. A composition comprising (a) a polyester, (b) a styrene-based thermoplastic elastomer modified with an unsaturated glycidyl compound, and (c) an inorganic filler, wherein the components (a), (b) and The proportion of (c) is (a)
50-95% by weight, (b) 1-40% by weight and (c)
A polyester resin composition, which is 4 to 45% by weight.