JPH07138378A - Production of thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To produce a thermoplastic elastomer composition excelling in flexibility, mechanical properties, etc., reduced in oil bleeding and excelling in extrudability, etc. CONSTITUTION:A particulate oil-extended olefin copolymer rubber comprising 100 pts.wt. olefin copolymer rubber of a Mooney viscosity (ML1+4, at 100 deg.C) of 180-350 and 20-150 pts.wt. mineral oil softener and an olefin plastic are directly fed to a twin screw extruder and dynamically crosslinked under conditions satisfying the relationships: 0.5<=alpha<=50, and 1.0>=beta>=0.003alpha+0.12 [wherein alphais the size of the oil-extended olefin copolymer rubber (g/100 particles), and betais the specific energy in the extruder (kW.hr/kg)].

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a thermoplastic elastomer composition. More specifically, the present invention relates to a method for producing an olefin-based thermoplastic elastomer composition which has excellent mechanical properties and can substitute for vulcanized rubber.

[0002]

2. Description of the Related Art Thermoplastic elastomer (hereinafter referred to as "TP
"E". ) Does not require a vulcanization process and can be processed with a normal thermoplastic resin molding machine, and its applications have been developed in a wide range of fields including automobile parts, home electric appliances parts and sundries. There is. Among them, the olefinic TPE composition is known from JP-A-58-26838. However, this composition is inferior to the vulcanized rubber in terms of flexibility, tensile strength at break, elongation at break, compression set, etc. in the field of vulcanized rubber replacement, and thus has limited applications.

In order to improve these properties, a softening agent such as a mineral oil type softener and a non-crosslinking type hydrocarbon oxide rubber compound is added to give flexibility, and a crosslinking aid is used in combination to increase the degree of crosslinking and to achieve compression set. Various attempts have been made to improve the distortion.
(For example, JP-B-56-15740 and JP-A-58-25340.
No. 58-152023, JP-A-59-58043, etc.). However, in these compositions, even if the degree of cross-linking is increased to improve the compression set, therefore, the flexibility decreases and the breaking strength and breaking elongation in the tensile test decrease, or the bleeding of the softening agent to the composition surface occurs. It has been difficult to obtain an olefinic TPE composition having a good balance of physical properties.

[0004]

SUMMARY OF THE INVENTION Under such circumstances, the problems to be solved by the present invention include vulcanization of an olefinic TPE composition in terms of flexibility and mechanical properties (particularly tensile breaking strength, breaking elongation, compression set). It is an object of the present invention to provide a method for producing an olefin-based TPE composition which can substitute for rubber and has good blow moldability, extrusion moldability, injection moldability and the like.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to overcome the drawbacks of the above-mentioned conventional methods, and as a result, using a specific particulate oil-extended olefin-based copolymer rubber and olefin-based plastic, The inventors have found that a composition obtained by dynamically cross-linking these by a specific method is excellent in appearance and the like with little bleeding, excellent in flexibility, mechanical properties and the like, and completed the present invention.

That is, according to the present invention, the Mooney viscosity (M
L _{1 + 4} 100 ° C.) is 180 to 350, and mineral oil softener is added to 100 parts by weight of olefinic copolymer rubber 100 parts by weight.
2 parts of the particulate oil-extended olefin copolymer rubber (A) and olefin plastic (B) contained in 150 parts by weight.
The present invention relates to a method for producing a thermoplastic elastomer composition, which is characterized in that it is directly supplied to a shaft extruder and is dynamically crosslinked in the presence of an organic peroxide under the condition that the following expression 2 is satisfied.

[0007]

## EQU2 ## 0.5 ≦ α ≦ 50 1.0 ≧ β ≧ 0.003α + 0.12 α: Size of the particulate oil-extended olefin-based copolymer rubber (A). (G / 100) β: Specific energy of extruder. (KW ・ hr / kg)

Further, the present invention relates to a method for producing the above-mentioned thermoplastic elastomer composition, characterized in that dynamic crosslinking is carried out at a maximum shear rate of 500 / sec or more.
The present invention will be specifically described below.

The olefin copolymer rubber (A) constituting the particulate oil-extended olefin copolymer rubber used in the present invention is, for example, ethylene-propylene copolymer rubber or ethylene-propylene-non-conjugated rubber. Diene rubber, ethylene-butene-1-non-conjugated diene rubber, propylene-
Like butene-1 copolymer rubber, it is an amorphous random elastic copolymer containing olefin as a main component. Of these, ethylene-propylene-non-conjugated diene rubber (hereinafter referred to as "EPDM") is particularly preferable. Examples of the non-conjugated diene include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, ethylidene norbornene and the like, and ethylidene norbornene is particularly preferable.

As a more specific example, the propylene content is 10 to 55% by weight, preferably 20 to 40% by weight.
Ethylene-propylene-ethylidene norbornene copolymer rubbers having an ethylidene norbornene content of 1 to 30% by weight, preferably 3 to 20% by weight are preferred. If the propylene content is less than 10% by weight, the flexibility is lost and 55
If it exceeds 5% by weight, mechanical properties are deteriorated, which is not preferable.
When the content of ethylidene norbornene is less than 1%, mechanical properties are deteriorated, and when it is more than 30% by weight, injection moldability is deteriorated, which is not preferable.

In the present invention, the 100 ° C. Mooney viscosity (ML 1 _{+ 4} 100 ° C.) of the olefinic copolymer rubber is 18
It is 0 to 350, preferably 200 to 300. 100
When the ℃ Mooney viscosity (ML _{1 + 4} 100 ℃) is lower than 180, the mechanical properties are deteriorated, and when it is higher than 350, the appearance of the molded article is deteriorated, which is not preferable.

In the present invention, the oil-extended olefin copolymer rubber is 20 to 150 parts by weight, preferably 3 parts by weight, of a mineral oil softener per 100 parts by weight of the olefin copolymer rubber.
It contains 0 to 120 parts by weight. If the amount is less than 20 parts by weight, the fluidity of the olefin-based TPE composition decreases,
In particular, extrusion processability and injection moldability are impaired, which is not preferable. On the other hand, if the amount is more than 150 parts by weight, the plasticity is remarkably increased and the workability is lowered, and further, the performance such as physical properties of the product is lowered, which is not preferable. Then, the Mooney viscosity (ML _{1 +} 41) of the oil-extended olefin-based copolymer rubber at 100 ° C.
00 ° C.) is preferably 30 to 150, more preferably 40 to 100. When it is lower than 30, mechanical properties are lost, and when it is higher than 150, moldability becomes difficult, which is not preferable.

The mineral oil-based softening agent used in the oil-extended olefin-based copolymer rubber is a high-boiling petroleum fraction that is blended for the purpose of improving processability and mechanical properties. Although there are system-based or aromatic-based systems, paraffin-based systems are preferably used. When the amount of aromatic components is large, the staining property becomes strong and the use for transparent products or light-colored products is limited, which is not preferable.

Next, the properties of an oil-extended olefin copolymer rubber (oil-extended EPDM) and a method for producing the same will be described by taking EPDM as an example. ML _{1 + 4 When a} large amount of a mineral oil-based softener is blended using EPDM having a temperature of 180 to 350 at 100 ° C,
It is possible to obtain an olefin-based TPE composition capable of satisfying both improvement of processability by securing flexibility and improvement of fluidity and improvement of mechanical properties at the same time. Generally, a mineral oil-based softening agent is used as a fluidity improver in an olefin-based TPE composition.
When oil-extended EPDM is not used, if 40 parts by weight or more of a mineral oil-based softening agent is added per 100 parts by weight of EPDM,
Bleed of the softening agent is generated on the surface of the TPE composition, and the product is contaminated and sticky, which is not preferable. But for example ML
_{1 + 4} 100 ° C. 180-350 EPDM 100 to 200 parts by weight of EPDM pre-blended with 20 to 150 parts by weight of a mineral oil-based softener, the oil-extended EPDM causes less bleeding of the softener, resulting in less product contamination and sticking. TPE with excellent physical properties such as breaking strength, breaking elongation, compression set, etc.
A composition can be obtained. Despite the large blending ratio of this mineral oil-based softening agent, the bleeding of the softening agent is not observed. When EPDM having a relatively high Mooney viscosity is used, the upper limit of the allowable amount of the mineral oil-based softening agent is extended. It is considered that the temperature rises and that the softener added in advance is uniformly dispersed in the EPDM.

A known method is used as the oil-extending method of EPDM. For example, using a device such as a roll or a Banbury mixer, a method of oil-extending by a method of mechanically kneading EPDM and a mineral oil-based softening agent, or adding a predetermined amount of a mineral oil-based softening agent to an EPDM solution, and then , A method of removing the solvent by a method such as steam stripping, and the like.
Of these, the preferred oil extension method is a method using an EPDM solution, and the EPDM solution is an EPDM obtained by polymerization.
A solution is used, but the operation is easy.

In the present invention, the method for obtaining the (A) particulate oil-extended olefin copolymer rubber from the oil-extended olefin copolymer rubber is as follows. 1. Grinding of bale rubber. (1) A method of crushing with a commonly used crusher for rubber. (2) A method of pulverizing at low temperature using a high speed mill or a jet pulverizer. 2. A method of granulating using an extruder or the like. 3. A method in which a sheet is formed using rolls, and this is granulated with a pelletizer or the like. 4. A method in which the crumb-like polymer obtained by removing the solvent after the polymerization is used as it is. Of these, 1 and 4 are the preferred methods. Here, the particle of the particulate rubber means an irregular particle,
Not only spherical and columnar shapes, but also rectangular parallelepiped shapes, flake shapes, crumb shapes, lint shapes, and the like are included, as well as foamed particles and the like having a void inside. That is, the form does not matter as long as it can be identified as individual particles. In addition, in order to prevent mutual adhesion of the particulate rubber, a small amount of an inorganic filler, an olefin-based plastic, an organic lubricant, a powder of an inorganic lubricant, and a liquid substance such as silicone oil are attached to the surface or kneaded into the rubber. Can be used in.

In the present invention, the size (α, g / 100) of the (A) particulate oil-extended olefin copolymer rubber is
As will be described later, it is important for the physical property balance of the thermoplastic elastomer composition obtained, and 0.5 ≦ α ≦ 50 g / 100
The number is preferably 1 ≦ α ≦ 40 g / 100.

The olefinic plastic (B) used in the present invention is polypropylene or a copolymer of propylene and an α-olefin having 2 or more carbon atoms. Specific examples of the α-olefin having 2 or more carbon atoms include ethylene, 1-butene, 1-pentene, and 3-methyl-.
1-betane, 1-hexene, 1-decene, 3-methyl-
1-Pentene, 4-methyl-1-pentene, 1-octene and the like. The melt flow rate of these polymers is 0.1
~ 100 g / 10 min is preferred, more preferably 0.5-
It is in the range of 50 g / 10 minutes. Melt flow rate is 0.
If it is smaller than 1 g / 10 minutes or larger than 100 g / 10 minutes, a problem may occur in workability.

In the present invention, the compounding weight ratio of (A) the particulate oil-extended olefin copolymer rubber and (B) the olefin plastic is (A) / (B) = 20 to 95/8.
It is preferably 0-5. More preferably (A) /
(B) = 35-90 / 65-10, more preferably,
(A) / (B) = 35-85 / 65-15.

In the present invention, the above α is the above component (A).
And (B) are indexes that greatly affect the step of directly supplying the extruder to the extruder and performing melt-kneading. Especially ML _{1 + 4} 100 ℃
When an olefin-based copolymer rubber having a large value is used, it has a great influence on the dispersibility and morphology of the composition comprising the copolymer rubber and the olefin-based plastic. The dispersibility and the like of the composition formed here significantly affect the physical properties and processability of the TPE composition obtained through the subsequent dynamic crosslinking step. In the present invention, α is 0.5 to 50 g /
Although it is in the range of 100 pieces, when α is smaller than 0.5, there is a risk that transport efficiency will deteriorate in the solid transport portion of the continuous kneading extruder and blockage will occur in some cases. In addition, the mixing and kneading properties in the kneading section of the kneading machine are deteriorated, and the obtained T
It is difficult to form a preferable morphology in the PE composition. α is preferably 1 to 40 g / 100. On the other hand, the particle size of the (B) olefin-based plastic does not have to be the same as the size (α) of the (A) particulate oil-extended olefin-based copolymer rubber, but it is generally about 1 to
It is preferably within the range of 10 g / 100.

As the organic peroxide for dynamically cross-linking the mixture of (A) the particulate oil-extended olefin-based copolymer rubber and (B) the olefin-based plastic, 2,5-dimethyl-2,5-di ( t-butylperoxy) hexane,
2,5-Dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,3-bis (t-butylperoxyisopropyl) benzene, 1,1-di (t-butylperoxy) 3 , 5,5-trimethylcyclohexane,
2,5-dimethyl-2,5-di (peroxybenzoyl) hexyne-3, dicumyl peroxide and the like. Of these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is particularly preferable in terms of odor and scorch. The organic peroxide is added in an amount of 0.005 to 2.0 parts by weight, preferably 0 to 100 parts by weight of the total of (A) the particulate oil-extended olefin copolymer rubber and (B) the olefin plastic. It can be selected in the range of 0.01 to 0.6. If it is less than 0.005 part by weight, the effect of the crosslinking reaction is small,
If it exceeds 2.0 parts by weight, it is difficult to control the reaction and it is not economically advantageous.

In producing the composition of the present invention, N, N'-m- serves as a cross-linking aid during dynamic cross-linking with an organic peroxide.
Peroxide crosslinking aids such as phenylene bismaleimide, toluylene bismaleimide P-quinonedioxime, nitrobenzene, diphenylguanidine, trimethylolpropane, or divinylbenzene, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate,
A polyfunctional vinyl monomer such as allyl methacrylate can coexist. By blending such a compound, a uniform and mild crosslinking reaction and a reaction occur between the olefin-based copolymer rubber and the olefin-based plastic, and it is possible to improve the mechanical properties. The amount of the crosslinking aid added is selected in the range of 0.01 to 4.0 parts by weight based on 100 parts by weight of the total of (A) the particulate oil-extended olefin copolymer rubber and (B) the olefin plastic. You can It is preferably 0.05 to 2.0 parts by weight. 0.01
If it is less than 4 parts by weight, the effect is difficult to appear, and if it exceeds 4 parts by weight, it is not economically advantageous.

A specific method for producing a TPE composition by dynamically crosslinking a mixture of (A) the particulate oil-extended olefin-based copolymer rubber and (B) the olefin-based plastic will be described below. First, the particulate olefin-based copolymer rubber (A) and the olefin-based plastic (B) are directly supplied and mixed in a specific ratio to a twin-screw extruder, and melt-kneaded.
Next, an organic peroxide is preferably supplied from a supply port provided on the downstream side of the extruder to perform dynamic crosslinking, whereby the desired TPE composition is obtained. In the production of the TPE composition according to the present invention, the particulate oil-extended olefin-based copolymer rubber (A), the olefin-based plastic (B) and the organic peroxide are fed to a twin-screw extruder to obtain the following formula 3. The dynamic heat treatment is performed under the conditions that are satisfied.

[0024]

0.5 ≦ α ≦ 50 1.0 ≧ β ≧ 0.003α + 0.12 α: Size of the particulate oil-extended olefin-based copolymer rubber (A). (G / 100) β: Specific energy of extruder. (KW ・ hr / kg)

Here, the specific energy means a dynamic heat treatment.
Drive power of extruder (HP ₁: KW) same from
Color operation with screw speed (without feed)
Drive power (HP₂: KW) minus the value extruded
Machine (Qkg / hr) divided by
The unit is KW · hr / kg. This specific energy
It can be adjusted by changing the operating conditions of the machine. Immediately
However, the number of screw rotations increases and the screen pack
The ratio of
The amount of energy can be increased. In addition,
It also changes depending on the shape of the Liu, and the screw groove
The specific energy increases when a shallow depth is used.
In the present invention, the specific energy (β) is a copolymer rubber
Is defined by the number 3 defined by the particle size (α) of
Must be equal to or greater than
It is essential that it not
Partially crosslinked rubber-resin composition
I can only get things. However, the specific energy (β) is 1.5
KWhr / kg, preferably less than about 1.0KWhr / kg
Is desirable, and under conditions that exceed this, mechanical
The conversion of energy into frictional energy locally warms it.
Increase the degree of deterioration, deterioration of the processed object and deterioration of physical properties.
There is a turnaround, and the addition of such excess energy
Neither unnecessary nor economical.

As the axial extruder for giving such energy, a twin-screw continuous kneading extruder equipped with a screw or rotor having a design capable of improving kneading performance, or materials in the extruder move in a molten state. It is possible to use a combination of extruders which are connected as much as possible.
As a screw design that has the function of improving kneading,
Examples include kneading discs and rotors. In the present invention, the twin-screw continuous kneading extruder can be rotated either in the different direction type or in the same direction type. Examples of the commercially available type of the twin-screw continuous kneading extruder include ZSK type (W & P Company), TEX type (Japan Steel Works, Ltd.), TEM type (Toshiba Machinery Co., Ltd.), and KTX type (Kobe Steel Works). ) And Mixtron LCM type (Kobe Steel Co., Ltd.). In the present invention, it is possible to give a sufficient specific energy by changing the operating conditions even if a normally used single-screw extruder is used, but the partially cross-linked copolymer rubber and the resin component are separated from each other. A well-dispersed TPE composition cannot be obtained and therefore its physical properties are also not good. The dynamic heat treatment using a twin-screw extruder is carried out at a temperature at which a material, particularly an olefinic plastic, melts, generally 150 to 280.
C., preferably 200 to 250.degree. C., generally under conditions of a residence time of about 15 to 240 seconds, preferably about 30 to 180 seconds.

In the present invention, the maximum shearing rate at the time of dynamic crosslinking is preferably 500 / sec or more, but this can only be achieved by using the above continuous kneading extruder, and the conventional shearing rate of Banbury, roll, etc. It is difficult to obtain with a batch type mixer. When the shear rate is less than 500 / sec, it is difficult to obtain a TPE composition having low production efficiency and excellent appearance and physical properties.

Next, specific steps of the preferred manufacturing method will be described. In the melt-kneading step of the particulate olefin-based copolymer rubber (A) and the olefin-based plastic (B), first, the components (A) and (B) are fed to the extruder by a belt type screw or a screw. Type feeder can be used,
A screw type pushing device can also be used. Ingredient (A) /
The blending weight ratio of (B) is such that (A) / (B) is 20 to 95 /
80 to 5 is preferable, and when the content of (B) is less than that, physical properties are likely to be deteriorated during dynamic crosslinking, and shear heat generation tends to be large. In order to form a good morphology of the composition comprising the components (A) and (B), it is desirable that the kneading section has a screw or rotor having a design having a kneading property improving function.

Next, in the dynamic crosslinking step, the organic peroxide can be used by diluting it with a liquid or powdery substance. Supply from the supply port provided in the middle of the extruder
In the case of a liquid, it can be carried out by appropriately injecting it into the supply port with a metering pump or into a cylinder, and in the case of a powder, supplying it to the supply port with a metering feeder. As the diluent, oil, organic solvent, inorganic filler (silica,
Talc etc.) can be used. It is desirable that the dynamic cross-linking portion has a design having a function of improving kneading property, for example, in a twin-screw kneading machine, a rotor, a kneading disk, or the like. The maximum shear rate in the dynamically crosslinked portion is preferably 500 / sec or more. However, if it is too high, heat generation due to shearing tends to cause decomposition, deterioration, and coloration.

In the present invention, an olefinic plastic may be additionally added. The supply location can be upstream or downstream of the extruder. Moreover, it does not matter even after the dynamic crosslinking step. In the present invention, when a crosslinking aid is used, it is preferable to supply it before or at the same time as the supply of the organic peroxide. In the present invention, an inorganic filler, an antioxidant, a weatherproofing agent, an antistatic agent, a lubricant, a coloring pigment and the like can be added if necessary, but these may be fed from any part of the extruder. Regarding addition of the mineral oil-based softening agent, it may be supplied at any part of the extruder. However, in the case of adding a large amount, it is preferable to separately supply from multiple injection ports. When a mineral oil-based softening agent is required, it is more preferably used as the above-mentioned particulate oil-extended olefin copolymer rubber.

The olefin-based TPE composition according to the present invention may be used as a substitute for vulcanized rubber in weather strips, ceiling materials, interior sheets, van bar moldings, side moldings, air boilers, air duct hoses, and various other automotive parts. Backing etc. For civil engineering materials and building materials, waterproofing materials, jointing materials, window frames for construction, etc. For sports equipment, grips for golf clubs and tennis rackets. Hose tubes, gaskets, etc. for industrial parts. For home electric appliances, there are hoses and backings. Hereinafter, the embodiments of the present invention will be specifically described by the present invention.

[0032]

EXAMPLES The contents of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The test methods used for measuring the physical properties in these examples and comparative examples are as follows.

(1) Mooney viscosity (ML _{1 + 4} 100 ° C.)
(Hereinafter, referred to as "viscosity".): Based on ASTM D-927-57T. EPDM
The viscosity (ML ₁ ) of was calculated by Equation 4.

[0034]

## EQU00004 ## log (ML ₁ / ML ₂ ) = 0.0066 (ΔPHR) ML ₁ : viscosity of EPDM. ML ₂ : Oil-extended EPDM viscosity. ΔPHR: Oil extension amount per 100 parts by weight of EPDM.

(2) Extrudability: USV 25 mmφ extruder manufactured by Union Plastics. Full flight type screw, screw rotation speed 30 rpm. Use T-die,
The judgment was made on the extruded skin. The judgment ranks are as follows. ○: excellent △: good ×: bad

(3) Oil bleeding property: 7
Let stand for 1 hour in an oven at 0 ° C and visually observe the oil bleeding on the surface of the molded product. The judgment rank is as follows. ○: No bleeding. Δ: There is slight bleeding. ×: There is bleeding.

The production conditions by the twin-screw continuous kneading extruder are shown below. Equipment used: TEX44HCT (L / D = made by Japan Steel Works)
38.5 Number of Cylinder Blocks = 11) The structure of the cylinder is the outer one, that is, 11 cylinder blocks C1 to C11 are provided, and the first supply port is provided at C1 and the vent port is provided at C10. A second supply port for supplying peroxide or the like is provided in C5. D is the die exit. In addition, in the outer 1, the direction from C1 to C11 is the downstream side of the extruder.

[0038]

[Outer 1]

Example 1 EPDM (ethylene-propylene-ethylidene norbornene copolymer rubber, viscosity = 242, propylene = 28% by weight, iodine value = 12) in a 4% by weight hexane solution,
100 parts by weight of a mineral oil-based softening agent (Diana Process Oil PW380 manufactured by Idemitsu Kosan) was added per 100 parts by weight of EPDM, and then the oil-extended EPDM (viscosity = 53) desolvated by steam stripping was crushed by a crusher to obtain a size. A particulate oil-extended olefinic copolymer rubber (oil-extended EPDM) having (α) of 4.5 g / 100 was obtained. Then this oil exhibition E
87 parts by weight of PDM, MFR (230 ° C, 2.16 kg load)
No. 10, 13 parts by weight of crystalline polypropylene (PP) having a size of 1.9 g / 100, and 1.1 parts by weight of N, N-metaphenylene bismaleimide (BM) with a super mixer (Kawata Manufacturing Co., Ltd.) Mix for seconds. This mixture
A twin-screw continuous kneading extruder having a cylinder configuration shown in External 1 (TEX44HCT manufactured by Japan Steel Works, L / D = 38.5, cylinder set temperature 180 to 200 ° C., die set temperature 2
It is melt-kneaded by supplying it at 30 kg / hr from the first supply port (C1 of the outside 1) at 30 ° C, and then the second supply port (C of the outside 1).
From 5), 2,5 dimethyl-2,5-di (tert-butylperoxy) hexane (hereinafter referred to as "organic peroxide") is used as a mineral oil oil (paraffin oil Diana Process Oil PW90 manufactured by Idemitsu Kosan Co., Ltd.). ), Which was diluted to 50% by weight (PO-1) at 480 g / hr,
0.2 kW. The physical energy and extrusion moldability were evaluated by applying a specific energy (β) of hr / kg to perform dynamic crosslinking and pelletizing. The maximum shear rate of the dynamically crosslinked part was about 1600 / sec. The evaluation results are shown in Table 1.

Comparative Example 1 In Example 1, 87 parts by weight of oil-extended EPDM was added to JSR.
EP-24 (ML 1 _{+ 4} 100 ° C. = 70, propylene content = 44% by weight, EPDM with iodine value = 12, manufactured by Japan Synthetic Rubber Co., Ltd.) 43.5 parts by weight and mineral oil softener 43.5 parts by weight The same procedure as in Example 1 was carried out except that it was replaced. The evaluation results are shown in Table 1.

[0041]

[Table 1]

[0042]

According to the present invention, mechanical properties such as tensile strength, elongation at break, and compression set in the low hardness region of olefin-based TPE are improved, and further, workability and bleeding of oil onto the surface of a molded product are achieved. It is possible to provide a method for producing an olefin-based TPE composition which has an improved property and can substitute for a vulcanized rubber.

Claims (8)

[Claims] 1. A Mooney viscosity at 100 ° C. (ML _{1 + 4} 100
Particulate oil-extended olefin-based copolymer rubber (A) and olefin-based plastic (B) containing 20 to 150 parts by weight of a mineral oil-based softening agent per 100 parts by weight of an olefin-based copolymer rubber having a temperature of 180 to 350. ) Is directly supplied to a twin-screw extruder, and dynamic crosslinking is carried out in the presence of an organic peroxide under the condition of satisfying the following formula 1, a method for producing a thermoplastic elastomer composition. ## EQU1 ## 0.5 ≦ α ≦ 50 1.0 ≧ β ≧ 0.003α + 0.12 α: Size of the particulate oil-extended olefin-based copolymer rubber (A). (G / 100) β: Specific energy of extruder. (KW ・ hr / kg) 2. A 100 ° C. Mooney viscosity (ML 1 _{+ 4} 100 ° C.) of the (A) particulate oil-extended olefin copolymer rubber is 30.
The manufacturing method according to claim 1, wherein 3. The method according to claim 1, wherein the mineral oil softener is a paraffin softener. 4. The compounding weight ratio of (A) the particulate oil-extended olefin-based copolymer rubber and (B) the olefin-based plastic is (A) / (B) = 20-95 / 80-5. 1. The manufacturing method according to 1. 5. The (A) olefin-based copolymer rubber constituting the particulate oil-extended olefin-based copolymer rubber is ethylene-based rubber.
A propylene-non-conjugated diene copolymer rubber.
The manufacturing method described. 6. An ethylene-propylene-non-conjugated diene copolymer rubber is an ethylene-propylene-ethylidene norbornene copolymer rubber having a propylene content of 10 to 55% by weight and an ethylidene norbornene content of 1 to 30% by weight. The manufacturing method according to claim 5. 7. The production method according to claim 1, wherein the olefin-based plastic (B) is at least one selected from polypropylene and propylene-α-olefin copolymer resin. 8. The production method according to claim 1, wherein the dynamic crosslinking is performed at a maximum shear rate of 500 / sec or more.