JPH09111061A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an olefinic thermoplastic elastomer composition, excellent in fluidity, molding processability and mechanical properties and good in molding appearance such as color tone. SOLUTION: This resin composition comprises (A) 30-90 pts.wt. ultrahigh- molecular weight α-olefin copolymer having 5-30dl/g intrinsic viscosity, (B) 70-10 pts.wt. polyolefin having 0.4-4dl/g intrinsic viscosity and (C) a plasticizer such as a process oil in an amount of 10-100 pts.wt. based on 100 pts.wt. total amount of the components (A) and (B).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel thermoplastic resin composition. More specifically, the present invention relates to an olefin-based thermoplastic resin composition that is excellent in fluidity, moldability, mechanical properties, and has a good appearance of a molded product such as a color tone.

[0002]

2. Description of the Related Art A thermoplastic elastomer has a low hardness and flexibility, but can be molded by a processing method such as extrusion molding or injection molding, like conventional thermoplastic resins.
In recent years, applications are expanding mainly in the fields of home appliances and automobiles.

Of these, olefin elastomers are
In addition to having the basic characteristics as a thermoplastic elastomer, it has low specific gravity, heat resistance, and excellent recyclability, so it is expected to be in demand mainly in the automotive field where the need for weight reduction and recycling is increasing. Stretching out.

As an olefinic thermoplastic elastomer composition, a composition comprising (1) a crystalline polyolefin component such as polypropylene or polyethylene and a rubber component (EPR) such as ethylene-propylene copolymer is known.
This composition can be obtained, for example, by melt-kneading polypropylene and EPR using an extruder or the like. (2) Polypropylene and EPDM (ethylene-
A composition comprising a propylene-diene terpolymer) and a process oil, and an EPDM component partially crosslinked with an organic peroxide or the like is known. This composition is:
Due to its excellent moldability and rubber elasticity, it is widely used in industrial parts such as the automobile field.

[0005]

However, in the composition of the above (1), when the amount of the rubber component is increased in order to obtain the flexibility as an elastomer, the melt fracture phenomenon at the time of high speed extrusion molding or the injection molding. At the time, a flow mark, a delamination phenomenon, and a defective molding phenomenon such as poor weld adhesion are likely to occur. Further, since such a composition is inferior in rubbery properties such as permanent elongation, it may not be suitable for use as an elastomer.

Further, the composition produced by dynamic crosslinking as described in (2) above requires a crosslinking reaction step during production, and thus the production step is complicated. Further, since the color of the product tends to be yellowed, there is a problem that it is not suitable for a light-colored product or an application requiring transparency.

[0007]

As a result of intensive studies on the above problems, the present inventors have identified an α-olefin copolymer having a very high molecular weight, a highly fluidized polyolefin, and a plasticizer. A composition obtained by compounding in a sufficient amount can be a thermoplastic resin composition that is excellent in fluidity and moldability, has flexibility as an elastomer, mechanical properties, and gives a molded product with good color tone. They have found the present invention and completed the present invention.

That is, the present invention (A) has an intrinsic viscosity of 5 to 3
0-ultra high molecular weight α-olefin copolymer 30 to 80% by weight, (B) polyolefin having an intrinsic viscosity of 0.4 to 4
70 to 20% by weight and (C) the total amount of the above ultrahigh molecular weight α-olefin (A) and polyolefin (B) 10
A thermoplastic resin composition comprising 10 to 100 parts by weight of a plasticizer with respect to 0 parts by weight.

The α-olefin constituting the ultrahigh molecular weight α-olefin copolymer (A) used in the present invention includes ethylene, propylene, 1-butene and 4-methyl-olefin.
1-pentene and the like. The copolymer is formed by selecting two or three or more of these α-olefins. In particular, ethylene-propylene random copolymer, propylene-ethylene block copolymer, ethylene-1-butene random copolymer, ethylene-propylene-1-butene ternary random copolymer, etc., mainly ethylene, propylene, butene A copolymer as a component is preferably used.

Among these, the propylene content is 20 to
80 mol% of a propylene-ethylene block copolymer or an ethylene-propylene random copolymer is the most preferable.

An ethylene-propylene-diene random copolymer having mechanical properties, thermal properties, and melt properties which are essentially the same as those of the ethylene-propylene random copolymer can be used as well.

In the present invention, the intrinsic viscosity of the above ultrahigh molecular weight α-olefin copolymer (A) measured in a 135 ° C. tetralin solvent is 5 to 30 dl / g, preferably 8 to 25 dl / g. . That is, the intrinsic viscosity is 5 dl /
When it is less than g, mechanical properties such as tensile permanent elongation are deteriorated and, for example, molding defects such as poor adhesion of a weld line of a molded product in injection molding are likely to appear. On the other hand, when the intrinsic viscosity exceeds 30 dl / g, not only the fluidity of the composition is impaired, but also the mixing and dispersion with the polyolefin (B) component becomes extremely poor, so that the elongation at break of the resulting thermoplastic composition is increased. Mechanical properties such as degree are impaired, and many lumps appear on the surface of the molded product.

In order for the thermoplastic composition of the present invention to have good flexibility, the ultrahigh molecular weight α-olefin copolymer (A) needs to have sufficient flexibility at room temperature, and crystal melting The heat is preferably 20 J / g or less.

As the ultra-high molecular weight α-olefin copolymer (A), for example, a propylene block copolymer polymerized by the method disclosed in JP-A-5-320468 is used, and its handling is easy. Therefore, the manufacturing process is simplified, which is preferable.

Polyolefin (B) used in the present invention
Is, for example, homopolypropylene, propylene-ethylene block copolymer, propylene-ethylene random copolymer, polyethylene, polybutene, propylene-butene copolymer, ethylene-butene copolymer, ethylene-4methyl-1-pentene copolymer. Coalescence, ethylene-vinyl acetate copolymer and the like are used. Among these, homopolypropylene and a propylene-ethylene block copolymer having an ethylene content of 20% by weight or less are most preferable.

Polyolefin (B) used in the present invention
Has an intrinsic viscosity of 0.4 to 4 dl / g, preferably
It is 0.7-2.5 dl / g. Intrinsic viscosity 0.4dl
If it is less than / g, the mixing and dispersion with the α-olefin copolymer (A) will be poor, and the mechanical properties and appearance will be impaired. On the other hand, when the intrinsic viscosity exceeds 4 dl / g, the fluidity of the composition is lowered and the processability is impaired.

When the composition of the present invention is used in an application requiring heat resistance, it is used as a polyolefin (B) in an amount of 150.
Good heat resistance when using a resin having essentially polypropylene properties, such as polypropylene, propylene-ethylene block copolymer, and propylene-ethylene random copolymer, which have a melting point of ℃ or more and a heat of fusion of 70 J / g or more. And is particularly preferable.

Further, it is also possible to use those obtained by individually decomposing these with an organic peroxide or the like to reduce the molecular weight, or those modified with maleic anhydride or the like.

As the plasticizer (C) in the present invention, an aliphatic hydrocarbon having a molecular weight of 2000 or less, liquid paraffin, polyethylene wax, mineral oil and the like, and derivatives thereof are used. Among these, paraffin-based mineral oils, which have little pollution and odor and have a good color, are preferably used.

The blending amount of the ultrahigh molecular weight α-olefin copolymer (A) and the polyolefin (B) in the present invention is 30 to 80 parts by weight of the ultrahigh molecular weight α-olefin copolymer (A). B) 70 to 20 parts by weight. The ultra high molecular weight α-olefin copolymer (A) is 30
If it is less than 10 parts by weight, the flexibility will be impaired, and if it exceeds 80 parts by weight, the fluidity will decrease.

In the present invention, the blending ratio of the plasticizer (C) is 10 to 10 relative to the total 100 parts by weight of the ultrahigh molecular weight α-olefin copolymer (A) and the polyolefin (B).
0 parts by weight. When the blending ratio of the plasticizer (C) is less than 10 parts by weight, the fluidity of the composition is lowered and the extrusion processability or injection moldability and moldability are impaired. Meanwhile, 1
If it exceeds 100 parts by weight, the bleeding of the plasticizer on the surface of the molded product will increase, and the appearance and feel will be very poor.

In the present invention, the ratio [ηA] / [ηB] of the intrinsic viscosity [ηA] of the ultrahigh molecular weight α-olefin copolymer (A) and the intrinsic viscosity [ηB] of the polyolefin (B) is 5 It is preferably in the range of -30, especially 9-25.
Is more preferably in the range. [ηA] / [ηB] is 5
If it is less than 30, the weld line of the injection-molded product tends to be conspicuous and the melt fracture phenomenon tends to appear. If it exceeds 30, the ultrahigh molecular weight α-olefin copolymer (A) and the polyolefin (B) Mixing and dispersion tend to deteriorate, and the surface of the molded article tends to have lumps or elongation at break.

The thermoplastic resin composition of the present invention contains fillers that have been conventionally used, such as calcium carbonate, whisker carbonate, calcium silicate, talc, silica, carbon fiber, graphite, as long as the characteristics are not significantly impaired. Glass fiber, glass sphere, glass flake, shirasu balloon, hydrotalcite, clay, alumina, molybdenum disulfide, barium sulfate, mica, diatomaceous earth,
Aluminum sulphate, calcium sulphate, basic magnesium sulphate, potassium titanate, wollastonite, sepiolite, zonotolite, asbestos, etc. or colorants such as carbon black, titanium oxide, zinc white,
Red iron oxide, ultramarine blue, navy blue, azo pigment, nitroso pigment, lake pigment, phthalocyanine pigment, quinacridone pigment, or a combination of a plurality of kinds of these fillers and pigments can be blended.

In the present invention, a conventional antioxidant or weathering agent such as a phenol-based, sulfite-based, phenylalkane-based, phosphite-based, or amine-based stabilizer, or a plurality of these types of antioxidants is used. Antioxidants and weathering agents can be combined and compounded. Especially,
Tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl)
Suppressing the decrease in the molecular weight of the ultrahigh molecular weight α-olefin copolymer (A) by blending an appropriate amount of a phosphite-based processing stabilizer such as 4,4′-biphenylene diphosphite and distearyl pentaerythritol diphosphite. This is preferable because the effect of

Further, in the thermoplastic resin composition of the present invention, oleic acid amide, N-stearyl erucic acid amide, erucic acid amide, elaidic acid amide, and lauric acid which have been conventionally used are contained in the thermoplastic resin composition so long as the characteristics are not significantly impaired. Acid fatty acid amides, valmitic acid amides, stearic acid amides, methylenebisstearic acid amides, methylenebisoleic acid amides, ethylene bisstearic acid amides, saturated fatty acid amides such as ethylenebisoleic acid amides, unsaturated fatty acid amides, bis fatty acid amides, etc. The slipperiness of the surface of the molded product can be imparted by adding a lubricant or a combination of plural kinds of lubricants.

Further, in the thermoplastic resin composition of the present invention, a cationic, anionic, nonionic or amphoteric antistatic agent, which has been conventionally used, or a plurality of antistatic agents, which are conventionally used, is used in the range that does not significantly impair the characteristics. Antistatic agents of different types can be combined and compounded. In particular, nonionic antistatic agents such as polyoxyethylene alkylamines, polyoxyethylene alkylamides, fatty acid esters thereof, and fatty acid esters of glycerin are preferred.

The thermoplastic resin composition of the present invention also includes
A compounding agent that can be usually compounded with a polyolefin, such as a crystallization nucleating agent such as an aromatic carboxylic acid metal salt, a sorbitol derivative, an organic phosphate and talc, or a chlorine scavenger such as a higher fatty acid metal salt, is used in the present invention. It can be blended within a range that does not impair the purpose.

The above-mentioned compounding agents can be compounded both at the stage of producing the thermoplastic resin composition of the present invention and at the time of molding.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited. As a suitable method, the intrinsic viscosity is 0.4 to 4 after melt kneading the ultrahigh molecular weight α-olefin copolymer having an intrinsic viscosity of 6 to 30 dl / g and a plasticizer.
A method characterized by melt-kneading with a dl / g polyolefin can be mentioned.

Specifically, first, the ultra-high molecular weight α-olefin copolymer (A) and the plasticizer (C) are mixed using an extruder, a Banbury mixer or the like to prepare a masterbatch. After that, this masterbatch is melt-kneaded with the polyolefin (B) using an extruder or the like, whereby there are few spots and the decrease in the molecular weight of the ultrahigh molecular weight α-olefin copolymer is small, and the appearance, moldability, and mechanical properties are improved. It is possible to obtain a composition having excellent physical properties.

Further, instead of the above-mentioned method for preparing a masterbatch, an ultrahigh molecular weight α-
A method in which a dry blend of the olefin copolymer (A) and the plasticizer (C) is supplied, melt-kneaded, and the polyolefin (B) is supplied to the extruder through a side feed port provided in the middle of the cylinder, and further melt-kneaded. Also by the above, it is possible to obtain a composition having less lumps and less decrease in the molecular weight of the ultrahigh molecular weight α-olefin copolymer, and having excellent appearance, moldability, and mechanical properties.

In contrast to the above method, in the usual method of simply melt-kneading the ultrahigh molecular weight α-olefin copolymer (A), the polyolefin (B) and the plasticizer (C), it is possible to mix them uniformly. Very difficult. For example, when (A) and (B) and (C) are simply melt-kneaded at the same time by a twin-screw extruder, the mixing and dispersion are very poor, and very many spots appear on the surface of the molded product. Similarly, when (A) and (B) are melt-kneaded and then (C) is added and melt-kneaded, the mixing and dispersion are also very poor. Further, in order to improve the dispersibility, when the kneading temperature is increased or when the mixture is kneaded for a long time using a mixer or the like, the mixing and dispersion is improved, but the molecular weight of the ultrahigh molecular weight α-olefin copolymer is lowered, and therefore the mechanical It adversely affects the physical properties and moldability.

In the above method, any device may be used for mixing the ultra-high molecular weight α-olefin copolymer (A) with the polyolefin (B) and the plasticizer (C). The method of melt-kneading using a twin-screw extruder has excellent productivity.

When the thermoplastic resin composition of the present invention is produced by melt kneading in an atmosphere of an inert gas such as nitrogen, the molecular weight of the ultrahigh molecular weight α-olefin copolymer (A) is This is a preferred embodiment because it has the effect of suppressing the deterioration and yellowing of the product.

Further, in the above-mentioned method, when a propylene resin is used as the polyolefin (B), in order to improve the fluidity, the amount of the composition does not exceed the range of the intrinsic viscosity specified at the time of melt kneading, and the amount is not more than Even if an amount of the organic peroxide selected from the range of 0.01 to 0.5 parts by weight is added to 100 parts by weight of the total of the high molecular weight α-olefin copolymer (A) and the polyolefin (B). Good.

The thermoplastic resin composition of the present invention can be molded into various shapes by any conventionally used molding method such as injection molding, extrusion molding, calender molding, compression molding and the like. Further, a laminate with another material can be formed by a two-color molding method, a co-extrusion method, a sticking method, or the like. Since the thermoplastic resin composition of the present invention has high compatibility with polyolefins such as polypropylene and polyethylene, a laminate having excellent adhesive strength can be easily formed using these resins.

[0037]

EFFECT OF THE INVENTION The thermoplastic resin composition of the present invention has good fluidity and molding processability while having flexibility. In particular, when molding is performed by injection molding, since the flow length is long and the bond strength of the weld is high, it is possible to easily mold a molded product having a thin portion or a large molded product. Therefore, it can be used as automobile parts such as mudguards, bumpers, side moldings, home appliances, miscellaneous goods, shock absorbers for toys, wheel tires, suckers, and the like. Moreover, since the extrusion characteristics are good, a good molded product can be obtained by extrusion molding. Therefore, it can be used for sheets, skin materials, nets, bands, films and the like.

[0038]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Prior to the examples, the measuring method used in the examples will be described.

(1) Intrinsic viscosity Measured in tetralin at 135 ° C.

(2) Heat of fusion Using DSC200 manufactured by Seiko Denshi Kogyo Co., Ltd., JI
The heat of fusion was measured according to the method specified in S: K7122.

(3) Buds A No. 1 type test piece defined by JIS: K6251 was prepared by injection molding, and the number of burrs on the surface of the molded product was evaluated by visual observation, and the following three grades were evaluated.

◯: Almost no lumps are seen Δ: Some lumps are seen ×: Many lumps are seen (4) Bleed JIS: K6251 No. 1 type test piece is prepared by injection molding, and 60 ° C. After being left in the oven for 1 hour, the bleeding of the oil on the surface of the test piece was evaluated with the naked eye, and the following three grades were evaluated.

○: Almost no bleeding △: Slight bleeding ×: Severe bleeding (5) Melt Fracture Capillary Rheometer Capirograph B-1 manufactured by Toyo Seiki Seisaku-sho, Ltd. and an inner diameter of 0.5 mm , Length 5
Existence of melt fracture is checked by extruding resin at a measurement temperature of 200 ° C. and an extrusion amount of 1432 mm ² / min (apparent shear rate: 1946 S ⁻¹ ) using a capillary of mm, and visually observing the extruded product. It was

(6) Flow length A mold having a spiral flow passage having a thickness of 2 mm and a width of 10 mm was attached to an injection molding machine having a mold clamping force of 150 tons.
Injection molding was performed at a heating cylinder temperature of 200 ° C., an injection pressure of 60 MPa, and a mold cooling water temperature of 40 ° C. Then, the flowed distance was measured and defined as the flow length.

(7) Weld Conspicuity The shape of the No. 1 type tensile test piece specified in JIS: K7113 was injection-molded by injecting resin simultaneously from both ends, and the weld formed in the central portion of the test piece. The visibility of the line was visually observed and the following three-stage evaluation was performed.

◯: The weld line is hardly noticeable Δ: The weld line is slightly noticeable ×: The weld line is noticeable (8) Tensile fracture elongation A tensile test was performed by the method specified in JIS: K6251 to measure the tensile fracture elongation. . As the test piece, a No. 3 type test piece was prepared by injection molding and used.

(9) Permanent elongation The permanent elongation was measured by the method specified in JIS: K6262. As the test piece, a No. 1 type test piece defined by JIS: K6251 was prepared by injection molding and used.

(10) A hardness A hardness was measured using an A type spring type hardness tester specified in JIS: K6253.

(11) Vicat Softening Temperature The Vicat softening temperature was measured according to the method specified in JIS: K7206. However, the test load applied to the test piece was 2.5N.

The ultrahigh molecular weight α-olefin copolymer (A), polyolefin (B) and plasticizer (C) used in the following examples and comparative examples are as follows.

(A-1): An ultrahigh molecular weight ethylene-propylene copolymer obtained by polymerizing in accordance with the method described in JP-A-5-320468, having a propylene content of 64 mol%, [η ] = 16.5 (dl /
g), ΔH = 8 (J / g).

(A-2): Ultra-high molecular weight ethylene-propylene copolymer obtained by polymerization according to the method described in JP-A-5-320468, having a propylene content of 67 mol%, [η ] = 9.0 (dl / g),
ΔH = 10 (J / g).

(A-3): An ultra-high molecular weight ethylene-propylene copolymer obtained by polymerizing according to the method described in JP-A-5-320468, having a propylene content of 69 mol%, [η ] = 6.9 (dl / g),
ΔH = 13 (J / g).

(A-4): An ultrahigh molecular weight ethylene-propylene copolymer obtained by carrying out polymerization according to the method described in JP-B-7-53771, which has a propylene content of 64 mol% and [η ] = 3.8 (dl / g), Δ
H = 8 (J / g).

(A-5): An ultrahigh molecular weight ethylene-propylene copolymer obtained by carrying out polymerization according to the method described in JP-A-5-320468, having a propylene content of 33 mol%, [η ] = 32.2 (dl /
g), ΔH = 9 (J / g).

(A-6): An ultra-high molecular weight ethylene-propylene copolymer obtained by polymerizing according to the method described in JP-A-5-320468, having a propylene content of 38 mol%, [η ] = 26.4 (dl /
g), ΔH = 8 (J / g).

(A-7): An ultra-high molecular weight ethylene-propylene copolymer obtained by polymerization according to the method described in JP-A-5-320468, having a propylene content of 77 mol%, [η ] = 10.5 (dl /
g), ΔH = 35 (J / g).

(B-1): 100 parts by weight of "Tokuyama Polypro PN180G" manufactured by Tokuyama Corporation as peroxide
A low molecular weight polypropylene obtained by adding 0.15 parts by weight of 3-bis- (t-butylperoxyisopropyl) benzene and melt-kneading at 220 ° C., and [η] = 0.8.
2 (dl / g) and ΔH = 108 (J / g).

(B-2): "Tokuyama Polypro PN790G" manufactured by Tokuyama Corporation, [η] = 1.0 (dl /
g), ΔH = 90 (J / g).

(B-3): "Tokuyama Polypro RB110" manufactured by Tokuyama Corporation, [η] = 2.9 (dl /
g) and ΔH = 103 (J / g).

(B-4): 100 parts by weight of "Tokuyama Polypro PN180G" manufactured by Tokuyama Corporation as a peroxide 1,
It is a low molecular weight polypropylene obtained by adding 0.26 parts by weight of 3-bis- (t-butylperoxyisopropyl) benzene and melt-kneading at 220 ° C., and [η] = 0.
52 (dl / g) and ΔH = 98 (J / g).

(B-5): 100 parts by weight of "Tokuyama Polypro PN180G" manufactured by Tokuyama Corporation as peroxide
A low molecular weight polypropylene obtained by adding 0.42 parts by weight of 3-bis- (t-butylperoxyisopropyl) benzene and melt-kneading at 220 ° C., and [η] = 0.
33, ΔH = 96 (J / g).

(B-6): Polypropylene obtained by polymerizing in accordance with the method described in JP-A-3-7704, [η] = 5.6 (dl / g), ΔH =
107 (J / g).

(B-7): "PE" manufactured by Tokuyama Corp.
R. M352E ″, and [η] = 0.95 (dl /
g) and ΔH = 30 (J / g).

(B-8): Low density polyethylene "Petrosene 356" manufactured by Tosoh Corporation, [η] = 0.78
(Dl / g) and ΔH = 117 (J / g).

(B-9): Ethylene-propylene random copolymer "Tufmer P00" manufactured by Mitsui Petrochemical Industry Co., Ltd.
80K ″, [η] = 0.82, ΔH = 0 (J /
g).

(C) Plasticizer: PW3 manufactured by Idemitsu Kosan Co., Ltd.
80 (paraffin-based mineral oil (process oil)) Examples 1 to 14 and Comparative Examples 1 to 9 The α-olefin copolymer (A) and the plasticizer (C) were used in a nitrogen atmosphere using a biaxial kneading extruder. The mixture was melt-kneaded at 200 ° C. to prepare a masterbatch. This masterbatch and polyolefin (B) were kneaded and mixed at 200 ° C. in a nitrogen atmosphere using a twin-screw kneading extruder to obtain a desired composition. The composition and evaluation items of the obtained composition are shown in Table 1.

Comparative Example 10 The masterbatch prepared in Example 1 was evaluated alone. The composition and evaluation items are shown in Table 1.

Example 15 A dry blend of an ultrahigh molecular weight α-olefin copolymer (A) and a plasticizer (C) was fed from a hopper of a twin-screw kneading extruder, and a polyolefin was fed from a side feed port provided in the middle of the cylinder. (B) was fed to a twin-screw kneading extruder,
The desired composition was obtained by melt-kneading at 0 ° C. The composition and evaluation items of the obtained composition are shown in Table 1.

[0071]

[Table 1]

Claims (2)

[Claims] 1. An ultrahigh molecular weight α-olefin copolymer (A) having an intrinsic viscosity of 5 to 30 dl / g, 30 to 80% by weight,
(B) 70 to 20% by weight of a polyolefin having an intrinsic viscosity of 0.4 to 4 dl / g, and (C) the ultrahigh molecular weight α.
A thermoplastic resin composition comprising 10 to 100 parts by weight of a plasticizer based on 100 parts by weight of the total amount of the olefin (A) and the polyolefin (B). 2. The method according to claim 1, wherein the ultrahigh molecular weight α-olefin copolymer (A) and the plasticizer (C) are melt-kneaded and then melt-kneaded with the polyolefin (B). A method for producing a thermoplastic resin composition.