JPH05140429A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the subject compsn. excellent in the balance among stiffness, heat resistance, tensile elongation and strength, and weld strength. CONSTITUTION:The objective compsn. comprises 40-95wt.% polyester, 1-40wt.% thermoplastic styrenic elastomer modified with an unsatd. glycidyl compd., and 1-45wt.% talc surface-treated with a silane coupling agent.

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 has an excellent balance of rigidity, tensile elongation strength, weld strength, heat resistance and the like and is suitable for molded articles such as automobile interior / exterior parts, electric component parts 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. In particular, fiber-reinforced polyesters containing fibers such as glass fibers have high heat resistance and are used in a wide range of applications as materials replacing metals. However, the fiber-reinforced polyester has a problem that the tensile elongation resistance and the weld strength are remarkably lowered, and the fiber-reinforced polyester cannot be used for a part or the like having a lot of welds during molding. Therefore, the object of the present invention is to provide excellent rigidity of fiber-reinforced polyester,
It is intended to provide a polyester resin composition having improved tensile elongation properties and weld strength without impairing heat resistance.

[0003]

Means for Solving the Problems As a result of intensive investigations by the present inventors, a styrene-based thermoplastic elastomer modified with an unsaturated glycidyl compound and talc surface-treated with a silane coupling agent were identified as polyester. It was discovered that a polyester resin composition having improved tensile elongation strength and weld strength can be obtained without impairing the rigidity and heat resistance by blending in the proportion of, and reached the present invention.

That is, the present invention comprises (a) a polyester, (b) a styrene-based thermoplastic elastomer modified with an unsaturated glycidyl compound, and (c) talc surface-treated with a silane coupling agent. , The proportions of the components (a), (b) and (c) are respectively (a)
40-95% by weight, (b) 1-40% by weight and (c)
The polyester resin composition is 1 to 45% by weight.

The polyester resin composition of the present invention will be described in detail below. The polyester as the component (a) of the polyester resin composition of the present invention is a thermoplastic resin generally obtained by polycondensation of a saturated dicarboxylic acid and a saturated dihydric alcohol, such as polyethylene terephthalate, polypropylene terephthalate, polytetramethylene terephthalate ( Polybutylene terephthalate), polyhexamethylene terephthalate, polycyclohexane-1,4
Examples include dimethylol terephthalate and polyneopentyl terephthalate. 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.

The component (b) of the polyester resin composition of the present invention is a styrene thermoplastic elastomer modified with an unsaturated glycidyl compound. In the component (b), a styrene-based thermoplastic elastomer which is a raw material elastomer modified with an unsaturated glycidyl compound is
Styrene-based monomers, copolymers such as random, block, and graft of other monomers such as mono-olefins or di-olefins copolymerizable with styrene-based monomers,
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 include non-conjugated dienes such as dicyclopentadiene, 1,4-hexadiene, cyclooctadiene and methylnorbornene, and conjugated dienes such as butadiene and isoprene. Of these, butadiene and isoprene are preferred. Further, as the mono-olefin, in addition to ethylene, propylene, butene-1, hexene-1, 3-methylbutene-
Examples thereof include α-olefins having 3 or more carbon atoms such as 1,4-methyl-pentene-1, heptene-1, octene-1, and decene-1, and of these, ethylene and propylene are preferable.

The styrenic thermoplastic elastomer used as the raw material elastomer of the component (b) of the present invention is obtained by copolymerizing the above-mentioned suitable monomers by a well-known suitable method such as anionic polymerization or radical polymerization. You can Specific examples of preferable raw material elastomers include styrene-butadiene-styrene block copolymer (SBS) and its hydrogenated product styrene-ethylene-butylene-styrene block copolymer (SEB).
S), styrene-butadiene copolymer (SB) and hydrogenated products thereof, styrene-ethylene-butylene block copolymer (SEB), styrene-isoprene copolymer (S)
I) and its hydrogenated product, styrene-ethylene-propylene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS) and its hydrogenated product styrene-ethylene-propylene-styrene block copolymer An example is coalescence (SEPS).

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.

In the component (b) of the polyester resin composition of the present invention, the unsaturated glycidyl compound used as a modifier for various styrenic thermoplastic elastomers includes an unsaturated group capable of copolymerizing with an olefin in the molecule. Examples thereof include glycidyl compounds having a glycidyloxy group. 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.

A preferred modified thermoplastic elastomer in the component (b) of 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 specified unconditionally, 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 145 ° C. for 0.1 to 100 hours with stirring.

In any modification method, an ordinary radical polymerization catalyst can be used as a catalyst. For example, benzoyl peroxide, lauroyl peroxide, di-t-peroxide
Butyl, acetyl peroxide, t-butyl perbenzoate, dicumyl peroxide, perbenzoic acid, peracetic acid, t-butyl perpivalate, 2,5-dimethyl-2,5-di-t-butylperoxyhexyne And the like, and diazo compounds such as azobisisobutyronitrile. The amount of catalyst added is based on 100 parts by weight of the glycidyl compound for modification.
It is about 0.1 to 10 parts by weight. It is also possible to add a phenol-based or phosphorus-based antioxidant during the above graft reaction.

The modified styrenic thermoplastic elastomer thus obtained has a graft rate 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 minutes. Then
It is preferably used in the present invention.

As the component (c) in the polyester resin composition of the present invention, (c) talc surface-treated with a silane coupling agent is blended. The talc used here is a complex salt of magnesium oxide and silicic acid, and preferably has an average particle size of about 0.1 to 100 μm.

The silane coupling agent used as the surface treatment agent is not particularly limited, but preferably has a polar group such as an epoxy group, an amino group and a mercapto group, and an alkoxy group in one molecule.

Specific examples of such a silane coupling agent include vinyl silanes such as vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, and 3-methacryloxypropyltrimethoxysilane.
3-glycidoxypropyltrimethoxysilane, 2-
Epoxysilanes such as (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2-
(Aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-
Examples thereof include aminosilane such as phenyl-3-aminopropyltrimethoxysilane and mercaptosilane such as 3-mercaptopropyltrimethoxysilane. Among these, 3-glycidoxypropyltrimethoxysilane,

[0020]

[Chemical 1]

2- (3,4-epoxycyclohexyl)
Ethyltrimethoxysilane

[0022]

[Chemical 2]

Epoxysilanes such as are preferred. These surface treatment agents are usually used alone, but two or more kinds can be used simultaneously. As a method of performing the surface treatment, a method of immersing talc in a solution of the surface treating agent with the silane coupling agent and then drying it is used. The amount of the silane coupling agent used is 0.1 to 10 parts by weight, preferably 100 parts by weight of talc on a dry basis.
0.1-5 parts by weight. The amount of silane coupling agent is 0.
If it is less than 1 part by weight, the effect of improving the weld tensile strength of the composition is not recognized, and if it exceeds 10 parts by weight, talc becomes extremely sticky.

Next, the above components (a), (b) and (c)
The component (a) is 40 to 95% by weight, preferably 50 to 90% by weight, and the component (b) is 1 to 40% by weight.
Preferably 3 to 20% by weight, component (c) is 1 to 45% by weight, preferably 5 to 40% by weight. Component (a) is 4
If it is less than 0% by weight, the amount of polyester is too small, and 95% by weight.
When it exceeds, the effect of improving the physical properties of the polyester by the components (b) and (c) is not recognized. Further, even if the component (b) or the component (c) is less than 1% by weight, the component (b) is 40% by weight or the component (c) is more than 45% by weight, the rigidity,
A resin composition having a good balance of heat resistance, tensile elongation strength and weld strength cannot be obtained.

In the present invention, the polyolefin or olefin elastomer may be used in an amount of 1 to 20 parts by weight based on the total composition of the present invention as 100. Here, the olefin elastomer means two or more copolymer rubbers of α-olefins such as ethylene, propylene, butene-1, hexene-1, and 4-methyl-pentene-1, or α-olefins. And a monomer of another kind. Two or three of the above α-olefins
Specific examples of one or more copolymer rubbers include ethylene-propylene rubber (EPR) and ethylene-butene rubber (EB
R) and ethylene-propylene-diene rubber (EPD
M) can be mentioned. In the present invention, in addition to the above-mentioned substances, other fillers and reinforcing agents usually used in the field of resin compositions, heat stabilizers, light stabilizers, flame retardants, plasticizers for the purpose of further modifying them. , Antistatic agent, foaming agent,
A nucleating agent and the like can be appropriately added.

The polyester resin composition of the present invention is prepared by mixing each of the above components in 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.

[0027]

The polyester resin composition of the present invention obtained by blending polyester with a modified styrene thermoplastic elastomer and talc surface-treated with a silane coupling agent provides a balance between rigidity, heat resistance, tensile elongation strength and weld strength. The reason why it is excellent is not necessarily clear, but the modification of the polyester of (a) component and the (b) component of talc through polar groups such as epoxy group, amino group and mercapto group of the silane coupling agent on the surface of talc. It is considered that the styrene-based thermoplastic elastomer is dispersed in the styrene-based thermoplastic elastomer and uniformly mixed.

[0028]

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)]

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, GMA (glycidyl methacrylate) 1.5 parts by weight, and a catalyst (Perhexin 25B: manufactured by NOF CORPORATION) 0.03 parts by weight are dry blended, and then this is mixed with a single screw extruder having a diameter of 65 mm to 200
Melt kneading under conditions of ℃ and 100 rpm, melt flow rate (MFR, 230 ℃, 2.16kg load) 5g / 10min G
MA modified SEBS was obtained. The GMA graft ratio of this modified styrene-based thermoplastic elastomer was 1% by weight.

Surface-untreated talc Untreated talc: [Fuji Talc Co., Ltd., LMS 300, average particle size 1.2 μm] Surface-treated with a silane coupling agent
Talc surface treatment Talc: Talc (Fuji Talc Co., LMS
300, average particle size 1.2 μm, 100 parts by weight) was surface-treated with 3-glycidoxypropyltrimethoxysilane (silane coupling agent, Nippon Unicar Co., A187, 3 parts by weight).

Examples 1 to 5 and Comparative Examples 1 to 2 Polyester (PBT), GMA modified SEBS (modified SEBS), surface treated talc, untreated talc or glass fiber at a ratio shown in Table 1 in a Henschel mixer. After dry-blending by, the mixture was kneaded with a twin-screw extruder (L / D = 28) having a diameter of 45 mm at 250 ° C. and 200 rpm to obtain resin composition pellets. The polyester resin composition thus obtained was injection molded, and the flexural modulus, tensile yield strength, tensile elongation at break, weld tensile strength, heat distortion temperature and Izod impact strength of the molded product were measured. The results are also shown in Table 1.

[0032]

[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) Weld tensile strength (23 ° C): Weld was formed by pouring resin from two directions into the mold by an injection molding machine.
A m-thick sheet was created and punched with a JIS No. 2 dumbbell to obtain a test piece, and the tensile yield strength (ASTM D-638) was measured. (5) Heat distortion temperature (load 4.6 kg / cm ² ): Measured by ASTM D-648. (6) Izod impact strength (23 ° C): measured by ASTM D-256.

As is apparent from Table 1 above, the compositions obtained by blending polyester and GMA-modified SEBS with surface-treated talc (Examples 1 to 5) are compositions obtained by blending talc without surface treatment. The flexural modulus, tensile yield strength, weld tensile strength, and Izod impact strength are all superior to those of Comparative Example 1 (Comparative Example 1), and particularly the weld tensile strength is remarkably improved.

On the other hand, conventionally used fiber-reinforced polyester, that is, polyester and GMA-modified S
A composition obtained by adding glass fiber to EBS (Comparative Example 2: fiber-reinforced polyester) and the composition of the present invention (Examples 1 to 1)
In 5), the fiber-reinforced polyester shows a good tensile yield strength, but a significantly low tensile elongation at break. That is, it is understood that the polyester resin composition of the present invention is a polyester resin composition having a good strength balance of tensile elongation strength and weld strength without impairing the properties of polyester such as heat resistance and mechanical strength.

[0036]

As described in detail above, the polyester resin composition of the present invention comprises a polyester compounded with a modified styrene thermoplastic elastomer and talc surface-treated with a silane coupling agent. The resin composition has improved tensile elongation characteristics and weld strength without impairing the rigidity and heat resistance of the fiber-reinforced polyester. 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.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 4, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

[0032]

[Table 1]

Claims (1)

[Claims] 1. A composition comprising (a) a polyester, (b) a styrene-based thermoplastic elastomer modified with an unsaturated glycidyl compound, and (c) a talc surface-treated with a silane coupling agent, wherein the component ( The proportions of a), (b) and (c) are (a) 40 to 95% by weight, respectively.
(B) 1 to 40% by weight and (c) 1 to 45% by weight, a polyester resin composition.