JPS6333452A - Polyolefin resin composition - Google Patents

Abstract

PURPOSE:The titled composition useful as parts for automobiles, etc., having improved balance of impact strength, rigidity, heat distortion temperature, surface hardness, molding properties, etc., suppressed warpage in molding, obtained by blending elastomer with a lamellar inorganic filler, glass fibers and a modified polyolefin in a specific ratio. CONSTITUTION:(A) a wt% elastomer is blended with (B) b wt% lamellar in organic filler, (C) c wt% glass fibers and (D) the rest of a modified polyolefin in correlation of b>=1/3a, b>=-2a+25, b<=-2a+54, 15<=c<=40, and 0.107c<2>-(7.2-0.0725a-0.0482b)c-3.63a-2.15b+0.786a<2>+0.0923ab+0.0106 b<2>+95.7 <=0 to give the aimed composition having improved warpage caused by anisotropy of shrinkage factor of glass fiber orientation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyolefin resin composition. More specifically, the present invention applies to the automobile and home appliance fields,
A glass fiber-reinforced polyolefin resin composition that is suitable as a molding material in other industrial fields and has an excellent balance of impact strength, rigidity, heat distortion temperature, surface hardness, moldability, etc., and has significantly suppressed warping during molding. It is about things.

[Conventional technology]

In recent years, polyolefins such as polyethylene, polypropylene, and their copolymers have significantly expanded their uses as molding materials that are easy to mold and have excellent physical, mechanical, electrical, and chemical stability. It's here.

However, this polyolefin can be used for example in mechanical parts,
For structural materials or applications that are exposed to high temperatures, they may not be able to withstand the intended use due to insufficient mechanical strength, dimensional stability, heat resistance, etc., and are subject to limitations in use. There is.

Therefore, many proposals have been made regarding methods for reinforcing polyolefins, but among them, the method of filling polyolefins with glass fibers significantly increases the mechanical strength such as tensile strength and rigidity, and heat resistance of the polyolefins. This glass fiber-reinforced polyolefin is widely used as a material for industrial parts such as automobile parts and electrical parts.

However, this glass fiber reinforced polyolefin
When the molten resin cools and solidifies during molding, warpage occurs due to internal stress caused by the difference in shrinkage rate between the glass fiber and resin, the crystallization of the resin, and the anisotropy of the shrinkage rate due to the orientation of the glass fibers. There were problems such as deformation and lack of dimensional accuracy, which inevitably restricted its use in precision parts.

Therefore, various methods have been tried in the past in order to suppress the occurrence of warpage during molding of glass fiber reinforced polyolefin. For example, polyolefin compositions in which synthetic rubber or natural rubber, glass fibers, and powdered talc fillers are blended with polyolefins (Japanese Unexamined Patent Publication No. 136736/1982), modified crystalline polyolefins, glass fibers, and amorphous rubber-like elastic materials. (Japanese Patent Publication No. 59-2294 Tokyo), crystalline polypropylene, sizing agent-adhered glass fiber, modified polypropylene, non-grade ethylene-α-olefin copolymer, and inorganic filler. A filler-containing propylene polymer composition (Japanese Unexamined Patent Publication No. 59-226041) has been proposed.

However, although warping during molding is considerably suppressed in these compositions, mechanical strength such as impact strength and rigidity may be affected due to inappropriate blending ratios or lack of necessary components. There are problems such as insufficient fluidity, poor appearance due to decreased fluidity, and decreased surface hardness.

Furthermore, attempts have been made to suppress warping during molding by using fine glass fibers, but this increases the cost and is not practical.

[Problem that the invention seeks to solve]

The present invention improves the drawbacks of conventional glass fiber-reinforced polyolefins, and has an excellent balance of mechanical strength such as impact strength and rigidity, heat distortion temperature, surface hardness, and moldability. The object of the present invention is to provide a polyolefin resin composition containing ordinary glass fibers in which warpage is significantly suppressed.

[Means for solving problems]

The inventors of the present invention have conducted intensive research to achieve the above object, and have found that the object can be achieved by blending glass fiber, elastomer, and plate-shaped inorganic filler into modified polyolefin in a specific ratio. The present invention was completed based on this finding.

That is, the present invention provides a composition comprising 3% by weight of an elastomer, % by weight of a plate-shaped inorganic filler, % by weight of glass fiber C, and the balance consisting of a modified polyolefin, in which a and b are
The relationship of formula % formula % is satisfied, and C satisfies formula 15≦C≦40. 0.107c" - (7,2-0,0725a-0,0
482b) c-3,63a-2,15b+0.0786
a”+0.0923ab+0.0106b”+95.
The present invention provides a polyolefin resin composition that satisfies the relationship 7≦0.

Examples of the modified polyolefin used in the composition of the present invention include polyethylene modified with unsaturated carboxylic acids, derivatives of unsaturated carboxylic acids, chlorine, and vinylsilane;
Examples include polypropylene and ethylene propylene copolymer. As the unsaturated carboxylic acid used for the modification,
Examples include acrylic acid, methacrylic acid, maleic acid, tumalic acid, itaconic acid, crotonic acid, citraconic acid, sorbic acid, mesaconic acid, angelic acid, etc. Derivatives of the unsaturated carboxylic acids include acid anhydrides and esters. , amides, imides, metal salts, etc., such as maleic anhydride, itaconic anhydride, citraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, maleic acid monoethyl ester,
Acrylamide, maleic acid monoamide, maleimide,
Examples include N-butylmaleimide, sodium acrylate, and sodium methacrylate.

Among the various modified polyolefins, polypropylene modified with maleic anhydride or acrylic acid is particularly preferred.

The amount of modifier added in the modified polyolefin is 0.01 to 5
It is desirable that the amount is in the range of % by weight. In this case, the unmodified polyolefin is modified to reduce the amount of modifier added to 0.01.
The amount of the modifier added may be in the range of ~5% by weight, or alternatively, a modified polyolefin to which a high concentration of the modifier has been added may be prepared, and this and unmodified polyolefin may be blended so that the amount of the modifier added is in the range of 0°01 to 5% by weight. It may be adjusted to 5% by weight.

During this modification, organic peroxides such as benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, and t-butyl hydroperoxide are usually used to accelerate the degree of modification, and the amount of the organic peroxide is 100 parts by weight of the polyolefin. , preferably 0.01
-3.0 parts by weight.

There are no particular restrictions on the method for producing modified polyolefin, but for example, polyolefin, unsaturated organic acid or its derivative, and organic peroxide are blended, thoroughly mixed using a Henschel mixer, etc., and then heated and melt-kneaded at a temperature above the melting point of the polyolefin. This method can be used.

There are no particular restrictions on the glass fibers used in the composition of the present invention, and any glass fibers conventionally used for resin reinforcement can be used.
3 μm alkali-free glass fibers are preferred. There are no particular restrictions on the form of the glass fibers (they may be roving, chopped strands, strands, etc., but if the fiber diameter is too large, the strength of the composition will decrease,
In addition, there is a risk that the appearance will deteriorate, and if it is too thick, the fibers may break during kneading or molding, resulting in a decrease in strength.

In order to obtain a composition with superior heat resistance and mechanical strength, this glass fiber may be used with a coupling agent such as aminosilane, epoxysilane, borane, vinylsilane, or methacrylosilane, or a chromium complex, if desired. It may be used after surface treatment with a compound, boron compound, etc.

Examples of the elastomer used in the composition of the present invention include ethylene propylene rubber, ethylene propylene diene rubber, styrene butadiene rubber, styrene butadiene ethylene styrene rubber, acrylic rubber, epichlorohydrin rubber, butadiene rubber, etc. , preferably Mouni viscosity ML, or (100
Ethylene propylene rubber having a temperature (°C) of 10 to 100, more preferably 20 to 70 is suitable.

Examples of the plate-like inorganic filler used in the composition of the present invention include talc, mica, sericite, glass flakes, and clay. Among these, talc, mica, and sericite with an aspect ratio of 5 or more are preferred. suitable.

In the composition of the present invention, the content of the elastomer is 3% by weight, the content of the plate-like inorganic filler is 5% by weight, the content of glass fiber is C% by weight, and the content of modified polyolefin is (100-( a+b+C)) When set as overlapping %,
It is necessary for a and b to satisfy the following relationships: 2b≧1/3a, b≧−23+25, b−5a+24, and b≦−23+54. b < l / 3
In a, the surface hardness is low, and in b<-22+25, warpage during molding is large. On the other hand, when b>a+24, the impact strength is low, and when b>-2a+54, the heat distortion temperature is low. Preferably, a and b satisfy the following relationship.

FIG. 1 is a graph showing the relationship between a and b, with the horizontal axis representing a and the vertical axis representing b. In this figure, the area surrounded by solid lines is the range in which a and b can vary under the essential conditions of the present invention, and the area surrounded by dotted lines is the range in which a and b can vary under preferable conditions. As can be seen from this figure, the ranges in which a and b can fluctuate are each 1/
3-162/7.75/21-34.

From this relationship between a and b, arbitrary values of a and b are selected within the above range, and C is determined from the values of a and b,
Formula % Formula % More preferably 0.107c"-(7,2-0,0725a-0,0
482b) c-3,63a-2,15b+0.0786
a”+0.0923ab+0.0106b”+105
．． Determined by 7≦.

If C is thicker than this range, the moldability will decrease and the appearance will deteriorate; on the other hand, if it is smaller than this range, the heat resistance will decrease and warpage during molding will increase. The range of C determined by a and b is approximately in the range of 8.5 < c < 47.

In the composition of the present invention, when the values of a, b, and C have a relationship that satisfies the above formula, warpage, heat distortion temperature, impact strength, and surface hardness are well balanced and each exhibits high values.

The composition of the present invention can be prepared by heating and kneading each component using a conventional kneading machine such as a -screw extruder, twin-screw kneading machine, Pan Bali mixer, roll, Brabender, or kneader. However, it is preferable to side-feed only the glass fibers from the middle of the kneader using a twin-screw kneader.Adding an organic peroxide during this kneading process can further improve the warpage suppressing effect. improves.

Examples of the organic peroxide include benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-t-butyl peroxide, 1,3-bis(t-butylperoxyisopropyl)benzene, t-
Butyl peracetate, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylperoxy Benzoate, t-butyl perphenylacetate, t-butyl perisobutyrate, t-butyl per-5ec-oftate, t-butyl perpivalate, cumyl perpivalate, 1-butyl perdiethyl acetate, dichlorobenzoyl peroxide, etc. can be mentioned.

Among these, benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, 1.3-
Preferred examples include bis(t-butylperoxyisopropyl)benzene.

The blending amount of these organic peroxides is 0.05 to 0.1 part by weight, preferably 0.01 to 0.05 part by weight, per 100 parts by weight of the polyolefin resin composition.

Heat treatment is 200-260℃, preferably 210-250℃
This is done by melting and kneading at a temperature of . The treatment time is 0.1 to 5 minutes, preferably 0.3 to 3 minutes.

The composition of the present invention is usually kneaded in an extruder or the like to form a pellet-like compound and then subjected to processing. However, in special cases, each component is directly supplied to various molding machines, and while being kneaded by the molding machine, It can also be molded. As the molding method, methods such as extrusion molding, blow molding, injection molding, sheet molding, thermoforming, rotational molding, and lamination molding can be used.

(Examples) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

In addition, each physical property was calculated|required as follows.

Tensile strength: Based on JIS K 7113 Bending strength: Based on JIS K 7203 Flexural modulus
: Compliant with JIS K 7203 Eye shift impact strength: Compliant with JIS K 7110 (using notched test piece) Heat distortion temperature: Compliant with JIS K 7207 Warpage rate
: Diameter 150 m from the obtained pellet.

Form a disk with a thickness of 3 cranes, place the obtained disk on a flat plate, and measure the warp height (D+, Di) shown in Figure 2 from the plate surface to the curved part of the disk. Then, the warpage rate was calculated using the following formula.

DI+Dt Warpage rate -xlOO (%) ◎The value of the double warpage rate is 0 to 2% O: The value of the warpage rate is 2 to 4% 68 The value of the warpage rate is 4 to 6% g: The value of the warpage rate is 6% or more Surface hardness: Rockwell hardness JIS K 7202
Based on Production Example 1 99 parts by weight of 1-polypropylene (Idemitsu Polypro 750H) of polyolefin A and modified polypropylene with 5% by weight of maleic acid added (
Modified polyolefin A was produced by melt-kneading 1 part by weight of Idemitsu Polytac H-1000P) using a single-screw extruder to form pellets.

Production Example 2 Polyolefin B was added to 100 parts by weight of polypropylene (M18 g/10 min, density 0.90, trade name Idemitsu Polypro J750H) in a three-flow separable flask with a capacity of 1 liter equipped with a stirring blade and a reflux device. Terminal hydroxylated 1,2-polybutadiene (number average molecular weight 2000, trade name: N15soPBG-
2000 Nippon Soda ■) 5 parts by weight, maleic anhydride 20
parts by weight, 1.72 parts by weight of dicumyl peroxide, and 600 parts by weight of xylene, heated in an oil bath using an input heater, stirred, reacted at 120°C for 1 hour, and then heated at 140°C. The reaction was continued for 3 hours. After the completion of the reaction, it was cooled, precipitated in a large excess of acetone, filtered with suction, and then dried (
(at 70° C. for 50 hours) to obtain a white powdery polymer (modified polyolefin B). The amount of maleic anhydride added to this polymer was 0.5% by weight.

Production Example 3 Modified Polyolefin C A modified polyolefin C was obtained in the same manner as Production Example 2, except that 10 parts by weight of acrylic acid was used instead of 20 parts by weight of maleic anhydride. The amount of acrylic acid added to this product was 2.0% by weight.

Examples 1 to 17, Comparative Examples 1 to 9 After blending other components except glass fiber with a Henschel mixer, they were fed to the hopper tatami of a twin-screw kneader with a quantitative feeder, while the glass fibers were fed to the side with a quantitative feeder. Feed was performed, an organic peroxide was added as necessary, and the mixture was melt-kneaded at 220°C to obtain pellets.

After drying the obtained pellets at 100° C. for 3 hours, test pieces and disks with a diameter of 150 cranes were molded using an injection molding machine, and various physical properties were measured. The results are shown in the table.

In addition, in the column of modified polyolefin in the table, D is an unmodified polyolefin of Idemitsu Polypro J750H.

(The following is a blank space) [Effects of the invention] The glass fiber reinforced polyolefin resin composition of the present invention has the following properties:
It is a modified polyolefin blended with an elastomer, a plate-shaped inorganic filler, and glass fiber in a specific ratio, and it has an excellent balance of impact strength, rigidity, heat distortion temperature, surface hardness, moldability, etc. It has excellent characteristics such as extremely small warpage, and is suitably used as a molding material in, for example, automobiles, home appliances, and other industrial fields.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the amount of elastomer and the amount of plate-like inorganic filler in the composition of the present invention. The range in which the amount can vary, and the area surrounded by the dotted line is the range in which the amount can vary under preferable conditions. FIG. 2 is an explanatory diagram for measuring the warpage rate of a molded body. Figure 1 Nilastomer α (weight%)

Claims (1)

[Claims] 1. Elastomer a weight %, plate-shaped inorganic filler b weight %,
In a composition consisting of glass fiber c by weight % and the remainder being modified polyolefin, a and b satisfy the following relationships: b≧1/3a, b≧-2a+25, b≦a+24, b≦-2a+54, and c , formula 15≦c≦40, 0.107c^2-(7.2-0.0725a-0.0
482b) c-3.63a-2.15b+0.0786
a^2+0.0923ab+0.0106b^2+95
．． A polyolefin resin composition characterized by satisfying the relationship 7≦0.