JPH0458830B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to elastomeric compositions for molding. More specifically, it is highly flexible, impact resistant,
The present invention relates to a thermoplastic elastomer composition for molding that has excellent mechanical strength (bending elasticity), moldability (mold releasability), and appearance of molded products. In recent years, thermoplastic elastomeric compositions that are flexible, have rubber elasticity even without vulcanization, and are thermoplastic have attracted attention in fields such as automobile parts, home appliance parts, wire covering materials, footwear, and asphalt paving materials. has been done. [Prior art and its problems] Currently, various types of elastomeric compositions have been developed as the above-mentioned thermoplastic elastomeric compositions, such as polyolefin-based polyurethane-based, polyester-based, polystyrene-based, and polyvinyl chloride-based. , is commercially available. The polyolefin-based elastomer composition includes a propylene-α-olefin block copolymer, a hydrogenated derivative of a styrene-conjugated diene-styrene block copolymer, and, if necessary, an ethylene-α-olefin copolymer rubber. A blended composition is disclosed in JP-A-61-14248. However, although the above-mentioned composition has excellent mechanical strength and impact resistance, when it is made into a molded product, flow marks occur on the surface of the obtained molded product, resulting in poor appearance. is still not sufficient. In addition, a composition in which a propylene homopolymer is blended with a hydrogenated derivative of the above-mentioned styrene-butadiene-styrene block copolymer and, if necessary, an amorphous ethylene-α-olefin copolymer rubber, has a good property. There are problems in that the rubber elasticity is inhibited and the impact resistance at low temperatures is reduced, so if the composition uses a crystalline propylene-ethylene random copolymer instead of the above-mentioned propylene homopolymer, , when molded products are made using the composition, sink marks and burrs are likely to appear on the molded products obtained,
There are problems with molding processability (mold releasability) and problems such as blocking of molded products. The present inventors have conducted extensive research in order to solve the above-mentioned problems regarding polypropylene-based elastomeric compositions. As a result, a specific amount of a propylene-based copolymer containing a propylene-ethylene block copolymer () and a crystalline propylene-ethylene random copolymer () having a specific flexural modulus in a specific range was combined with the general formula A composition containing specific amounts of a hydrogenated derivative of a specific block copolymer represented by B-A-B', an amorphous ethylene-α-olefin random copolymer, and a higher fatty acid amide has the above problems. found that it is possible to solve
The present invention was completed based on this knowledge. As is clear from the above description, the purpose of the present invention is to provide molded products with excellent flexibility, impact resistance, mechanical strength, molding processability (mold releasability), appearance, and anti-blocking properties of molded products. An object of the present invention is to provide a propylene-based elastomeric composition for molding. [Means for solving the problems] The present invention has the following configuration. (a) Blending ratio (weight ratio) of propylene-ethylene block copolymer () and crystalline propylene-ethylene random copolymer () ()/
50 to 70% by weight of a propylene copolymer in which () is 8/2 to 2/8, (b) general formula B-A-B' (where A is a conjugated diene polymer block, and B
and B' are polymer blocks of aromatic vinyl compounds. ) 10 to 45% by weight of a hydrogenated derivative of a block copolymer represented by (c) amorphous ethylene-α
- An elastomeric composition for molding comprising 1 to 30 parts by weight of an olefin random copolymer and (d) 0.01 to 5 parts by weight of a higher fatty acid amide based on 100 parts by weight of the above (a) + (b) + (c). The propylene-ethylene block copolymer () and the crystalline propylene-ethylene random copolymer () used in the present invention have melt flow rates (MFR, 10 minutes of molten resin at 230°C and a load of 2.16 kg). Discharge amount) is 1 to 100g/10 minutes,
Preferably it is 10 to 60 g/10 minutes. If the MFR is less than 1 g/10 minutes,
The melt fluidity of the composition may deteriorate, making it difficult to mold large molded products such as automobile bumpers.
Moreover, if it exceeds 100 g/10 minutes, the impact resistance of the molded product obtained will decrease, which is not preferable. In addition, the crystalline propylene-ethylene random copolymer () to be used must have a flexural modulus of 3000 to 9000 Kgf/cm ² as measured in accordance with JIS K6758, particularly 5000 to 9000 Kgf/cm 2 . 8000Kg
f/cm ² is preferred. Further, the crystalline propylene-ethylene random copolymer () of the present invention also includes a crystalline propylene-ethylene-butene ternary random copolymer having a flexural modulus of 3000 to 9000 Kgf/cm ² . If the flexural modulus exceeds 9,000 Kgf/cm ² , an elastomeric composition with good flexibility cannot be obtained, and if the flexural modulus is less than 3,000 Kgf/cm ² , it will not be possible to obtain a molded product. This is not preferable because it may reduce the mechanical strength of the molded product and may deteriorate the mold releasability during molding. Further, the blending ratio (weight ratio) ()/() of the propylene-ethylene block copolymer () and the crystalline propylene-ethylene random copolymer () is 8/2 to 2/
If the blending ratio exceeds 8/2, flow marks will be observed on the appearance of the resulting molded product and the appearance will deteriorate;
If it is less than 8, sink marks and burrs will be observed in the molded product obtained, resulting in poor appearance, which is not preferable. In addition, the blending ratio of the propylene copolymer used in the present invention, which is a mixture of a propylene-ethylene block copolymer () and a crystalline propylene-ethylene random copolymer () in a specific range, is 50 to 50%.
70% by weight, preferably 55-65% by weight. If the blending ratio is less than 50% by weight, when the resulting composition is used to make a molded product, the surface appearance of the resulting molded product may be poor, and if it exceeds 70% by weight, This is not preferable because the low-temperature impact resistance of the obtained molded article decreases. The hydrogenated derivative of the block copolymer represented by the general formula B-A-B' used in the present invention has unsaturated bonds in the conjugated diene polymer block A and the aromatic vinyl compound polymer blocks B and B'. It is made by hydrogenating. Examples of the conjugated diene polymer block A represented by the above general formula include those having a structure obtained by polymerizing one or more conjugated dienes such as butadiene, isoprene, and chloroprene. In the present invention, it is preferable to use a polyptadiene block as the block A. Further, the polymer blocks B and B' represented by the above general formula have a structure obtained by polymerizing an aromatic vinyl compound, and preferably have a polystyrene structure. In the hydrogenated derivative of the block copolymer, 90% by weight or more of the conjugated diene polymer block A is hydrogenated, and 10% by weight or less of the aromatic vinyl compound block polymers B and B' are hydrogenated. Among them, the commercially available KRATON G-1652 (trade name) manufactured by Siel Chemical Co., Ltd. can be mentioned. Further, the hydrogenated derivative of the block copolymer has a solution viscosity of 300 to 800 cps, preferably 400 to 800 cps, in a 20% by weight toluene solution at a temperature of 25°C.
It is of 600cps. When the solution viscosity exceeds 800 cps,
This is undesirable because the compatibility with the propylene copolymer deteriorates, flow marks are generated on the surface of the molded product, and the fluidity of the molten resin during molding is reduced. The blending ratio of the hydrogenated derivative of the block copolymer is 10 to 45% by weight, preferably 15 to 45% by weight. If the blending amount is less than 10% by weight, the molding processability of the resulting composition, that is, the mold releasability, will be poor, and if it exceeds 45% by weight, the molded product will deteriorate when molded using the resulting composition. This is undesirable because flow marks may occur on the surface of the molded product and the mechanical strength of the molded product may be significantly reduced. The amorphous ethylene-α-olefin random copolymer used in the present invention acts as a soft segment in the composition, similar to the hydrogenated derivative of the block copolymer described above, and improves flexibility and impact resistance. It is something to give. The amorphous ethylene-α-olefin random copolymer is an α-olefin having 3 or more carbon atoms, particularly 3 to 18 carbon atoms, as an α-olefin component unit, such as propylene, butene-1, hexene-1, etc.
1,4-methyl-pentene-1, peptene-1,
Examples include octene-1, nonene-1, decene-1, etc., with propylene being preferred. Further, the α-olefin component in the ethylene-α-olefin random copolymer may be used alone or in combination of two or more types. Note that the ethylene-α-olefin random copolymer may contain a small amount of diene component. Preferred ethylene-α-olefin random copolymers are amorphous ethylene-propylene random copolymers or amorphous ethylene-propylene-
It is a dielene random copolymer. In the case of an amorphous ethylene-propylene random copolymer, the propylene content is usually 25 to 75% by weight, preferably 25 to 50% by weight. The amorphous ethylene
The blending ratio of α-olefin random copolymer is
It is 1 to 30% by weight. If the blending ratio exceeds 30% by weight, the molding shape of the resulting composition, that is, the mold releasability will deteriorate, which is not preferable. Examples of the higher fatty acid amide used in the present invention include oleic acid amide, erucic acid amide, and stearic acid amide, among which oleic acid amide is particularly preferred. The higher fatty acid amide is blended with an ethylene copolymer, a hydrogenated derivative of a block copolymer represented by the general formula B-A-B', and an amorphous ethylene-based copolymer.
The amount is 0.01 to 5 parts by weight, particularly preferably 0.1 to 2 parts by weight, based on a total of 100 parts by weight of the α-olefin random copolymer. If the blending ratio is less than 0.01 parts by weight, the mold releasability when molding the obtained composition into a molded product and the anti-blocking effect of the obtained molded product will be insufficient. If it exceeds this, the higher fatty acid amide will significantly bleed onto the surface of the resulting molded product, resulting in poor appearance of the molded product, which is not preferable. In the composition of the present invention, antioxidants, antistatic agents, colorants, decabromodiphenyl oxide, dodecachlorododecahydrodimethane, Organic halogen flame retardants such as nodibencyclooctene, flame retardant aids such as antimony oxide, antimony sulfide, and zirconium oxide, ultraviolet absorbers, plasticizers,
One or more of various additives such as extender oil for EPDM, softener for mineral non-aromatic rubber such as process oil, etc. can be blended. The method for producing the composition of the present invention includes a propylene copolymer, a hydrogenated derivative of a block copolymer represented by the general formula B-A-B', an amorphous ethylene-α-olefin random copolymer, and After stirring and mixing a predetermined amount of each higher fatty acid amide and a predetermined amount of one or more of the above-mentioned various additives using a ribbon blender, tumbler mixer, Hensel mixer (trade name), super mixer, etc., the mixture is rolled or bumped. Melt kneading temperature in remixer, extruder, etc. 150-300℃, preferably
A method of melt-kneading and pelletizing at 180 to 230°C can be exemplified. The thus obtained elastomeric composition for molding of the present invention can be used to produce various molded articles by various molding methods such as injection molding, extrusion molding, vacuum forming, and pressure forming. [Effects of the Invention] The elastomeric composition for molding of the present invention comprises a propylene-ethylene block copolymer () and a crystalline propylene-ethylene random copolymer ().
A propylene copolymer having a specific blending ratio, a hydrogenated derivative of a specific block copolymer represented by the general formula B-A-B', an amorphous ethylene-propylene random copolymer, and a higher fatty acid amide, respectively. It is a composition having a two-phase structure of a plastic phase and a rubber phase mixed in a predetermined amount, and is highly flexible, has excellent impact resistance and mechanical strength, and has particularly good moldability (mold releasability) and moldability. It is an elastomeric composition for molding that provides molded products with excellent anti-blocking properties and a good surface appearance. It can be suitably used for footwear and the like. [Examples] Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The ingredients and evaluation methods used in Examples and Comparative Examples are as follows. Ingredients (1) Propylene-ethylene block copolymer () manufactured by Chitsuso Petrochemical Co., Ltd., ethylene content
Propylene-ethylene block copolymer with a melt flow rate of 45 g/10 min, 12.5% by weight. (2) Crystalline propylene-ethylene random copolymer () manufactured by Chitsuso Petrochemical Co., Ltd., ethylene content 4.5% by weight, butene content 4.5% by weight, melt flow rate 45g/10 minutes, flexural modulus 6000Kgf/cm ² crystalline ethylene-ethylene-butene ternary random copolymer. (3) Hydrogenated derivative of a block copolymer represented by the general formula B-A-B' Hydrogenation of a styrene-butadiene-styrene block copolymer with a 20% by weight toluene solution having a solution viscosity of 550 cps at a temperature of 25°C Kraton G-1652 (trade name) manufactured by Shell Chemical Co., Ltd. and a hydrogenated derivative of styrene-butadiene-styrene block copolymer with a solution viscosity of 1100 cps in a 20% by weight toluene solution at a temperature of 25°C, manufactured by Shell Chemical Co. Clayton G-1650 (product name). (4) Amorphous ethylene-propylene random copolymer Mooney viscosity M ¹⁰⁰ ₁₊₄ = 24, EP02P (trade name) manufactured by Japan Synthetic Rubber Co., Ltd. (5) Higher fatty acid amide oleic acid amide (Diamid-200L (trade name) manufactured by Nippon Kasei Co., Ltd.). Evaluation method (1) Melt flow route (g/10 minutes): JIS K-
Compliant with 6758. (2) Flexural modulus (Kgf/cm ² ): Based on JIS K-6758. (3) Izotsu impact strength (Kgf・cm/cm): JIS
Conforms to K-7110 (temperature -40℃, 40Kg load). (4) Appearance of molded product Using the obtained pellets, the molding temperature was 230°C.
A flat plate having a length of 400 mm, a width of 80 mm and a thickness of 3 mm was injection molded under the molding conditions of an injection pressure of 600 Kgf/cm ² and a mold temperature of 30°C, and the surface condition of the obtained flat plate was evaluated by visual observation. It was considered good if there were no flow marks, silver streaks, sink marks or burrs on the surface. (5) Molding processability (mold releasability) Using the obtained pellets, the molding temperature was 230℃,
Injection pressure 600Kgf/cm ² , holding pressure, cooling time 20Kg
f/cm ² , 20 seconds, mold temperature 30℃ vertically
A cage with a mesh shape of 200 mm, width 300 mm, and depth 80 mm was molded by injection molding, and the releasability of the molded product from the cage mold was visually judged. (6) Blocking properties of molded products Using the obtained pellets, the molding temperature was 230°C.
A flat plate with a length of 150 mm, a width of 150 mm and a thickness of 3 mm was injection molded under the molding conditions of an injection pressure of 600 Kgf/cm ² and a mold temperature of 30°C. Five of the obtained flat plates were stacked, and a load of 2 kg was applied. I left it for a while. Thereafter, when the flat plates were peeled off, the state of blocking between the flat plates was visually observed and evaluated based on the following criteria. XX: The flat plate was destroyed when peeled off. ×: Blocking. ○: No blocking. Examples 1 to 6, Comparative Examples 1 to 6 Dimyristylthiodipropionate 0.1% by weight,
Tetrakis [methylene-3-(3,5-di-t-
Butyl-4-hydroxyphenyl)propionate] propylene-ethylene block copolymer and crystalline propylene-ethylene-butene ternary random copolymer containing 0.18% by weight of methane and 0.03% by weight of calcium stearate, Kraton G-
1652, amorphous ethylene-propylene random copolymer (EP02P), and oleic acid amide in the mixing ratios listed in Table 1 below, were placed in a Hensel mixer (trade name) and stirred and mixed for 3 minutes. The resulting mixture was melt-kneaded and extruded using a single-screw extruder with a diameter of 40 mm at a melt-kneading temperature of 200°C to form pellets. In addition, as Comparative Examples 1 to 6, each compounded component was placed in a Hensel mixer (trade name) at the proportions listed in Table 1 below, and stirred, mixed, melt-kneaded, and extruded in accordance with Examples 1 to 6. , pelletized. Using the pellets obtained in each of the Examples and Comparative Examples, test pieces for melt flow rate measurement and various evaluations were prepared, and various evaluation tests were conducted. These results are summarized in Table 1.

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Claims (1)

[Scope of Claims] 1 (a) Blending ratio (weight ratio) of propylene-ethylene block copolymer () and crystalline propylene-ethylene random copolymer () ()/
50 to 70% by weight of a propylene copolymer in which () is 8/2 to 2/8, (b) general formula B-A-B' (where A is a conjugated diene polymer block, and B
and B' are polymer blocks of aromatic vinyl compounds. 10 to 45% by weight of a hydrogenated derivative of a block copolymer represented by (c) amorphous ethylene-
An elastomeric composition for molding comprising 1 to 30 parts by weight of an α-olefin random copolymer and (d) 0.01 to 5 parts by weight of a higher fatty acid amide based on 100 parts by weight of the above (a) + (b) + (c). . 2 The propylene-ethylene block copolymer () and the crystalline propylene-ethylene random copolymer () have a melt flow rate of 1 to 100 g/10 minutes, and the crystalline propylene-ethylene random copolymer () The elastomeric composition for molding according to claim 1, which has a flexural modulus of 3000 to 9000 Kgf/cm ² .