JP2001187405A - Method for manufacturing olefin based thermoplastic elastomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing olefin based thermoplastic elastomer which is excellent in a surface appearance. SOLUTION: When crystalline propylene based resin and olefin based copolymer rubber are dynamically heat treated under presence of an organic peroxide, a double-screw extruder is used and a kneading part constituted so that by a plurality of kneading discs of at most 0.5 in a ratio [1/d] of average thickness [1 (mm)] per disc to a diameter of gyration [d (mm)], neither regular-feed capacity nor reverse feed capacity exists, is provided at a position of the screw after feeding at least organic peroxide to the extruder. Besides, a relation of 2.6<(N×Q)/R3<22.6 is kept among a barrel radius [R (mm)] of the double screw extruder, the number of rotations of the screws [N (rpm)] and a discharge amount [Q (kg/h)].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an olefin thermoplastic elastomer by dynamically heat treating a composition of a crystalline propylene resin and an olefin copolymer rubber in the presence of an organic peroxide. The present invention relates to a method for producing an olefinic thermoplastic elastomer which can efficiently produce an olefinic thermoplastic elastomer having excellent surface appearance.

[0002]

2. Description of the Related Art In recent years, a styrene-based, olefin-based, polyester-based, soft rubber-like material that does not require a vulcanizing step and has the same moldability as a thermoplastic resin.
Polyamide-based, polyurethane-based thermoplastic elastomers are attracting attention from the viewpoint of process rationalization and recycling,
It is widely used in the fields of automobile parts, home appliance parts, medical equipment parts, electric wires, and miscellaneous goods. Among them, crystalline propylene polymer resin and ethylene-propylene copolymer rubber or ethylene-propylene-non- A mixture with an olefin copolymer rubber such as a conjugated diene copolymer rubber, or an olefin heat which is dynamically heat-treated in the presence of an organic peroxide to crosslink the latter rubber to form a partially crosslinked product. Plastic elastomers are attracting attention as economically advantageous materials because they are relatively inexpensive. For example, the latter partially cross-linked olefin-based thermoplastic elastomer has an appropriate flexibility, Since there is no disappearance of the pattern and the like, active investigations have been made as a skin material for automotive interior materials to replace the conventional soft vinyl chloride resin.

However, since this olefin-based thermoplastic elastomer is a mixture, it is also a partially crosslinked product, so that coarse or heterogeneous dispersion of a crosslinked rubber is liable to occur. There is an inherent problem that the surface appearance of the resulting sheet or the like is deteriorated.

On the other hand, in order to solve the problems such as the surface appearance of the olefin-based thermoplastic elastomer, for example, Japanese Patent Application Laid-Open No. 58-25340 discloses a method of melt kneading using a twin screw extruder. A method for dynamically cross-linking is described in Japanese Patent Application Laid-Open No. 9-95540. A screw is provided with a kneading section configured to have a progressive feeding capability by a plurality of kneading disks having a specific average thickness. A method of melt-kneading and dynamically cross-linking using a screw extruder has been proposed.

[0005] However, according to the studies of the present inventors, these methods show that the surface appearance of the obtained olefin-based thermoplastic elastomer is still inferior or that the surface appearance can be improved unless the discharge rate is reduced. However, it was not yet sufficiently satisfactory for efficient production of an olefin-based thermoplastic elastomer having excellent surface appearance.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and accordingly, the present invention provides a composition comprising a crystalline propylene resin and an olefin copolymer rubber, which comprises an organic polymer. In producing an olefin-based thermoplastic elastomer by dynamically heat-treating in the presence of an oxide, a method for producing an olefin-based thermoplastic elastomer capable of efficiently producing an olefin-based thermoplastic elastomer having an excellent surface appearance. The purpose is to provide.

[0007]

According to the present invention, a composition of a crystalline propylene resin and an olefin copolymer rubber is dynamically heat-treated in the presence of an organic peroxide to form an olefin thermoplastic elastomer. In manufacturing, using a twin-screw extruder equipped with an interlocking co-rotating or counter-rotating twin-screw, the screw has a rotating diameter at least at a position after the supply of the organic peroxide to the extruder. [D (mm)]
Of the average thickness [l (mm)] per sheet to
/ D] is provided with a kneading section configured to have no forward feeding ability and no reverse feeding ability by using a plurality of kneading disks having a diameter of 0.5 or less, and a barrel radius [R (m
m)], the screw rotation speed [N (rpm)], and the discharge rate [Q (kg / hour)]. 2.6 <(N × Q) / R ³ <22.6

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the crystalline propylene resin as one of the components constituting the olefin thermoplastic elastomer composition is, for example, propylene homopolymer or propylene, ethylene, 1- Butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 4-methyl-1hexene, 1-heptene, 1-octene, 1-decene, etc. A copolymer with about 10 other α-olefins,
Specifically, for example, a propylene-ethylene copolymer,
Propylene-1-butene copolymer, propylene-ethylene-1-butene copolymer, propylene-4-methyl-1
-Pentene copolymer and the like. In the case of a random copolymer, the content of the other α-olefin in the copolymer is preferably 10% by weight or less, more preferably 7% by weight or less. In the case of a block copolymer, the content is preferably 40% by weight or less, more preferably 15% by weight or less.

The crystalline propylene-based resin in the present invention may be either a polymerized with a Ziegler-based catalyst or a polymerized with a metallocene-based catalyst. It is manufactured by a conventionally known polymerization method such as a bulk method and a solution method.

[0010] The crystalline propylene-based resin may be a resin selected from JI
The melt flow rate measured at 230 ° C. under a load of 2.16 kg according to SK7210 is 0.01 to 100 g /
It is preferably 10 minutes, more preferably 0.05 to 80 g / 10 minutes, and particularly preferably 0.1 to 60 g / 10 minutes. If the melt flow rate is less than the above range, the moldability tends to be inferior as a thermoplastic elastomer, while if it exceeds the above range, it tends to be difficult to obtain sufficient mechanical properties.

Further, the crystalline propylene-based resin may be a resin selected from JI
The density measured according to SK7112 is 0.870-
0.920 g / cm^Three0.880
~ 0.915 g / cm^ThreeIs more preferable, and 0.
885 to 0.910 g / cm ^ThreeEspecially preferred
No. If the density is less than the above range, the thermoplastic elastomer and
It is difficult to obtain sufficient mechanical strength and oil resistance
On the other hand, above the above range, the moldability is poor.
It tends to be.

In the present invention, the olefin copolymer rubber of the other component constituting the olefin thermoplastic elastomer composition includes ethylene, propylene,
1-butene, 3-methyl-1-butene, 1-pentene,
Copolymers of α-olefins having about 2 to 10 carbon atoms such as 4-methyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-decene, or And 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 6-methyl-1,5-heptadiene,
4-octadiene, 7-methyl-1,6-octadiene, cyclohexadiene, cyclooctadiene, dicyclopentadiene, 5-methylene-2-norbornene, 5
-Ethylidene-2-norbornene, 5-butylidene-2
Copolymers obtained by copolymerizing non-conjugated dienes such as -norbornene and 2-isopropenyl-5-norbornene, specifically, for example, ethylene-propylene copolymer, ethylene-1-butene copolymer, propylene- 1-butene copolymer, ethylene-propylene-1,4-hexadiene copolymer, ethylene-propylene-dicyclopentadiene copolymer, ethylene-propylene-5-ethylidene-2-
Norbornene copolymers and the like can be mentioned.

Among the above, a copolymer of ethylene and another α-olefin, or a copolymer of ethylene and another α-olefin and a non-conjugated diene is preferred. Is preferably from 5 to 70% by weight, more preferably from 10 to 60% by weight. Further, an olefin copolymer obtained by copolymerizing a non-conjugated diene is preferable, in which case, the content of the non-conjugated diene is
It is preferably from 0.5 to 12% by weight, more preferably from 1 to 10% by weight. When the content of the non-conjugated diene is less than the above range, it tends to be difficult to obtain sufficient mechanical strength and oil resistance as a thermoplastic elastomer,
On the other hand, if the ratio exceeds the above range, rubber elasticity tends to be inferior.

The olefin copolymer rubber of the present invention may be either a copolymer copolymerized in the presence of a Ziegler catalyst such as a vanadium compound or a copolymer copolymerized in the presence of a metallocene catalyst. Good.

[0015] The olefin copolymer rubber may have A
The Mooney viscosity [ML _{1 + 4} (100 ° C.)] measured at 100 ° C. according to STM D1646 is preferably 30 to 450, more preferably 50 to 420, and more preferably 80 to 400. Particularly preferred. If the Mooney viscosity is less than the above range, it tends to be difficult to obtain sufficient mechanical strength and oil resistance as a thermoplastic elastomer, while if it exceeds the above range, the moldability tends to be poor.

In the present invention, the composition ratio of the crystalline propylene resin and the olefin copolymer rubber is 5 to 80% by weight of the former resin and 95 to 20% by weight of the latter rubber. More preferably, the former resin is 10 to 65% by weight and the latter rubber is more preferably 90 to 35% by weight, and the former resin is 10 to 50% by weight and the latter rubber is 90 to 50% by weight. Particularly preferred. When the former resin is less than the above range and the latter rubber is more than the above range,
If the thermoplastic resin is inferior in molding processability, on the other hand, if the former resin is more than the above range and the latter rubber is less than the above range, rubber elasticity, flexibility and the like as the thermoplastic elastomer tend to be inferior.

The method for producing an olefin-based thermoplastic elastomer according to the present invention is characterized in that the composition of the crystalline propylene-based resin and the olefin-based copolymer rubber is dynamically heat-treated in the presence of an organic peroxide. Become.

Here, the term "dynamically heat-treating" means that the above composition is kneaded in a molten state using a twin-screw extruder described later. The crosslinking reaction by the peroxide proceeds, and a thermoplastic elastomer which is a partially crosslinked product is obtained.

The organic peroxide used at this time includes:
Organic peroxides commonly used in the production of conventional partially crosslinked olefin-based thermoplastic elastomers, specifically, for example, di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,5 -Dimethyl-2,5-di (t-butylperoxy) hexane, 2,
5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,3- or 1,4-bis (t-butylperoxyisopropyl) benzene, 1,1-di (t-butyl) Dialkyl peroxides such as peroxy) -3,3,5-trimethylcyclohexane, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) Hexane, 2,5-dimethyl-2,5
Peroxyesters such as -di (benzoylperoxy) hexine-3, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide,
Diacyl peroxides such as 2,4-dichlorobenzoyl peroxide; hydroperoxides such as diisopropylbenzene hydroperoxide; and the like.
Dialkyl peroxides are preferred and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane or 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 Is particularly preferred.

The amount of the organic peroxide to be used is preferably 0.005 to 3 parts by weight based on 100 parts by weight of the composition of the propylene resin and the olefin copolymer rubber. It is particularly preferably 0.05 to 2 parts by weight.

In the present invention, a crosslinking aid may be used together with the organic peroxide. Specific examples of the crosslinking aid include sulfur, p-quinonedioxime, nitrobenzene, and the like. Organic peroxide crosslinking aids such as diphenylguanisine and m-phenylenebismaleimide;
Allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth)
Examples include polyfunctional (meth) acrylates such as acrylate and trimethylolpropane tri (meth) acrylate, and polyfunctional vinyl compounds such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, and diallyl phthalate.

The amount of these crosslinking aids used is preferably 0.005 to 4 parts by weight based on 100 parts by weight of the composition of the propylene resin and the olefin copolymer rubber. , 0.05 to 3 parts by weight.

The olefin-based thermoplastic elastomer of the present invention may be blended with a rubber softener which is usually blended to impart processability, flexibility, etc. to the thermoplastic elastomer. Is preferably 20 to 200 parts by weight, more preferably 30 to 150 parts by weight, based on 100 parts by weight of the olefin copolymer rubber. The rubber softener may be incorporated into the thermoplastic elastomer by a so-called oil-extended rubber method, which is added in advance in a post-treatment step during the production of the olefin copolymer rubber.

As the rubber softener, a mineral oil-based softener is particularly preferable, which is generally a mixture of an aromatic ring, a naphthene ring, and a paraffin chain, and has a carbon number of the paraffin chain. Is 50% or more of the total number of carbon atoms in the paraffinic system, and the carbon number of the naphthene ring is 3% of the total carbon number.
The naphthene type which occupies 0 to 40% and the aromatic type whose aromatic ring occupies 30% or more of the total carbon number are classified into a naphthenic type and a paraffinic type. Has a number average molecular weight of 200 to 2,000.
A value of 0, especially 300 to 1,600 is preferred.

The olefin-based thermoplastic elastomer of the present invention further includes various resins and rubbers, glass fibers, fillers such as calcium carbonate, silica, talc, mica and clay; antioxidants; heat stabilizers; Various additives such as an absorbent, an antistatic agent, an antiblocking agent, a lubricant, a dispersant, a neutralizing agent, a flame retardant, and a coloring agent may be added as necessary.

The method for producing an olefin-based thermoplastic elastomer according to the present invention is characterized in that the composition comprising the crystalline propylene-based resin and the olefin-based copolymer rubber or a rubber softener is mixed with an organic peroxide. Alternatively, or further in the dynamic heat treatment in the presence of a crosslinking aid, using a twin-screw extruder equipped with an interlocking co-rotating or counter-rotating twin-screw, at least the organic peroxide of the screw At the position after the feed to the extruder, the rotating diameter [d (mm)]
Of the average thickness [l (mm)] per sheet to
/ D] is provided with a kneading section configured to have no forward feeding ability and no reverse feeding ability by using a plurality of kneading disks having a diameter of 0.5 or less, and a barrel radius [R (m
m)], the screw rotation speed [N (rpm)] and the discharge rate [Q (kg / hour)]. 2.6 <(N × Q) / R ³ <22.6

A twin screw extruder having a high kneading function is usually
A raw material supply port and a vent port, and a barrel with a jacket, arranged inside, a plurality of grooves are engraved on the surface,
Formed by two screws rotating in the same direction or different directions, and a die attached to the tip of the extruder, and a kneading part composed of a plurality of kneading disks in the middle of the screws, meshing with each other Or, they are provided in such a form that they do not mesh with each other. For example, they are commercially available as "TEXα" series from Nippon Steel Works, Ltd. and "TEM-SS" series from Toshiba Machine Co., Ltd. It is possible to increase the screw rotation speed to about 2,000 rpm, which is several times higher than that of the conventional screw.

The kneading section constituted by the plurality of kneading disks has, for example, an elliptical shape, a triangular shape,
A plurality of square-shaped kneading discs, such as meshing between two screws, or not meshing, is configured by arranging in a regularly shifted direction, for example, an elliptical shape To explain the case of a meshing type using four kneading disks, each kneading disk of one screw is shifted by 45 degrees in the feed direction of the screw and four disks are superposed, and each kneading disk of the other screw is Rotate the kneading disc in the feed direction,
A type in which forward feeding capability is provided in which four sheets are shifted one after another, and each kneading disc of one screw is shifted 45 degrees in the counter-feeding direction of the screw so that four sheets are stacked in a row and each knee of the other screw is shifted. The disc to the opposite direction, and set the phase to 90 degrees for one screw.
A type in which four sheets are shifted in a row to provide a reverse feed capability, and each kneading disc of one screw is shifted by 90 degrees so that two sheets are doubled in a row, and each knee of the other screw is stacked. The loading disc is classified as an orthogonal type in which the two discs are double doubly arranged with a phase shifted by 90 degrees with respect to one of the screws and have neither a forward feeding ability nor a reverse feeding ability.

According to the present invention, there is provided a twin-screw extruder provided with an interlocking co-rotating or counter-rotating twin-screw, which has a kneading section composed of a plurality of kneading disks and has a progressive feeding capability. As there is no reverse feed ability,
The kneading disk is configured to be the above-described orthogonal type, and the ratio [l / d] of the average thickness [l (mm)] per sheet to the rotational diameter [d (mm)] is 0.5.
It is as follows.

The ratio [l / d] is preferably 0.05 to 0.4, and more preferably 0.05 to 0.3. If the ratio [l / d] is less than the above range, the problem of a decrease in mechanical strength of the kneading disc tends to occur. On the other hand, if the ratio [l / d] exceeds the above range, heat generation due to shearing increases, causing a poor appearance. Etc. tend to occur easily.

In the present invention, the number of the kneading disks constituting one kneading section is preferably from 3 to 200, and more preferably from 5 to 50. The kneading unit is preferably composed of about 1 to 20 units, more preferably about 2 to 18 units, particularly preferably about 3 to 15 units, and the composition is transported between the respective units. For example, a full flight screw is used. If the number of kneading discs per one kneading unit is less than the above range, the kneading effect tends to be small, while if the number of kneading disks is less than the above range,
Heat generation due to shearing is increased, and there is a tendency that bumps and the like that cause poor appearance tend to occur.

In the present invention, the location of the kneading section must be, of course, at least the position after the organic peroxide is supplied to the extruder. The smooth cross-linking of the olefin copolymer rubber can be advanced.

Further, in the present invention, the barrel radius [R (mm)] of the twin-screw extruder and the screw rotation speed [N (rpm)
m)] and the discharge rate [Q (kg / hr)] must be extruded while maintaining the following relationship. 2.6 <(N × Q) / R ³ <22.6

It is preferable to extrude while maintaining the relationship of the following equation. 3.0 <(N × Q) / R ³ <20.0

The barrel radius [R (mm)] of the twin-screw extruder, the screw rotation speed [N (rpm)], and the discharge amount [Q (kg
/ Hour)] is less than the above range, it is difficult to efficiently produce an olefin-based thermoplastic elastomer, while if it is more than the above range, heat generation due to shearing becomes large and causes poor appearance. Bubbles and the like are likely to occur.

In the present invention, the maximum shear rate in the kneading section is set to 1,000 / sec or more and 10,000.
/ Sec, preferably 1,300 / sec or more,
More preferably, it is 8,000 / sec or less. If the maximum shear rate is less than the above range, kneading becomes insufficient, and if the maximum shear rate is more than the above range, heat generation due to shearing becomes large, and in any case, the appearance tends to be poor.

The maximum shear rate [γ _max (/ sec)]
Can be determined from the following formula based on the barrel inner diameter [D (mm)], the minimum gap [t (mm)] between the barrel inner wall and the screw kneading part, and the screw rotation speed [N (rpm)]. γ _max = [(πDN) / t] × (1/60)

The kneading temperature of the composition in the production method of the present invention is preferably from 170 to 290 ° C.
More preferably, the temperature is from 180 to 280 ° C.

In the present invention, the crystalline propylene-based resin and the olefin-based copolymer rubber, or the rubber softener, the organic peroxide, or the crosslinking aid, etc., are added to the twin-screw extruder. The supply order is not particularly limited, and, for example, a method in which these are collectively supplied from a raw material supply port of a twin-screw extruder and melt-kneaded, a crystalline propylene resin and an olefin copolymer rubber, or Further, a rubber softener is supplied from a first raw material supply port of a twin-screw extruder, and after these are melt-kneaded, an organic peroxide or further a crosslinking aid is supplied from a second raw material supply port by a plunger pump or the like. Then, a method of further kneading, a crystalline propylene resin and an olefin copolymer rubber, or further a rubber softener is supplied from a first raw material supply port of a twin-screw extruder, and after these are melt-kneaded, (2) A method of supplying a master batch of an organic peroxide or a crosslinking assistant by a crystalline propylene-based resin or / and an olefin-based copolymer rubber from a raw material supply port, and further kneading the mixture, the crystalline propylene-based resin and the olefin-based The copolymer rubber is supplied from the first raw material supply port of the twin-screw extruder, and after these are melt-kneaded, the rubber softener and the organic peroxide or further cross-linked from the second raw material supply port and thereafter. The auxiliaries may be supplied simultaneously or sequentially and further kneaded, or any other method, but in which at least the crystalline propylene resin and the olefin copolymer rubber are the first raw materials of the twin-screw extruder. It is preferable that the mixture is supplied from the supply port and melt-kneaded in advance, and then the organic peroxide or a crosslinking aid is supplied from the second raw material supply port and further kneaded.

The olefin-based thermoplastic elastomer produced by the production method of the present invention is obtained by dynamically heat-treating the composition comprising the propylene-based resin and the olefin-based copolymer rubber in the presence of the organic peroxide. By the dynamic heat treatment, a cross-linking reaction is carried out in the olefin-based copolymer rubber so that the gel content in the olefin-based copolymer rubber is 5 to 5.
It is a partially crosslinked product that has become 95%. If the gel content is less than the above range, the balance between moldability and mechanical properties tends to be inferior, while if it exceeds the range, mechanical strength such as impact resistance tends to be inferior.

The olefin-based thermoplastic elastomer produced by the production method of the present invention is excellent in moldability and surface appearance, and is suitable for extrusion molding, injection molding, compression molding and the like used in thermoplastic elastomers. By various molding methods such as molding, the molded article is formed into a desired shape as a simple substance or as a laminate with another material. Among them, it is suitably used as a skin material of an automobile interior material.

[0042]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. The crystalline propylene resin, olefin copolymer rubber, rubber softener, organic peroxide, and crosslinking aid used in the following Examples and Comparative Examples, and kneading of a twin-screw extruder and a screw. Part shape,
And the supply order of each raw material is shown below.

Propylene-ethylene random copolymer of crystalline propylene resin having an ethylene content of 2.8% by weight, a melt flow rate of 0.7 g / 10 min, and a density of 0.890 g / cm ³ (Novatec PP manufactured by Nippon Polychem Co., Ltd.) EG8 ").

Olefinic copolymer rubber Propylene content 30% by weight, 5-ethylidene-2-
Norbornene content 5.5% by weight, Mooney viscosity [ML
_{1 + 4} (100 ° C)] 390 ethylene-propylene-5
-Ethylidene-2-norbornene copolymer. (However, an oil-extended rubber containing 50% by weight of a rubber softener described below is used.) Propylene content: 34% by weight, 5-ethylidene-2-
Norbornene content 4.5% by weight, Mooney viscosity [ML
_{1 + 4} (100 ° C)] 289 ethylene-propylene-5
-Ethylidene-2-norbornene copolymer. (However, an oil-extended rubber containing 43% by weight of a rubber softener described below is used.) Propylene content: 34% by weight, 5-ethylidene-2-
Norbornene content 4.5% by weight, Mooney viscosity [ML
_{1 + 4} (100 ° C.)] 88 ethylene-propylene-5
Ethylidene-2-norbornene copolymer.

Rubber softener paraffin oil ("PW38" manufactured by Idemitsu Kosan Co., Ltd.)
0 "). Organic peroxide 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (40% by weight diluted with calcium silicate, “Kayahexa AD40C” manufactured by Kayaku Akzo). Crosslinking aid divinylbenzene (Sankyo Chemical Industry Co., Ltd.). Trimethylolpropane trimethacrylate (Sankyo Chemical Industry Co., Ltd.).

A barrel provided with a jacket having a first raw material supply port on the upstream side of the twin-screw extruder, a second raw material supply port with a plunger pump in the middle, and a vent port on the downstream side. Twin screw extruder (two screw grooves, barrel inner diameter (D) 47 mm, L / D 52.5, "TEX44α-II" manufactured by Nippon Steel Works) composed of a die. A second material supply port having a first material supply port on the upstream side, a second material supply port having a plunger pump in the middle, and a vent having a vent port on the downstream side, a barrel having a jacket, and a die attached to the tip end; Shaft extruder (2 screw grooves, barrel inner diameter (D) 32 mm, L / D 52.5, “TEX30α” manufactured by Japan Steel Works, Ltd.).

The shape of the kneading portion of the screw and the supply of each material
The feeding order is elliptical, and the ratio [l / mm] of the average thickness per sheet [l (mm)] to its rotating diameter [d (mm)]
d] is a perpendicular type in which five kneading disks of 0.2 are orthogonally arranged in a row, and subsequently, five kneading disks having a ratio [l / d] of 0.1 are fed in the reverse direction of the screw. A screw provided with a kneading section provided on the upstream side, wherein the kneading section is configured such that one unit is a reverse-feed type that is arranged in a row and eight units are provided with a full flight screw therebetween.
The crystalline propylene-based resin and the olefin-based rubber softener (including oil-softened rubber in the case of oil-extended rubber), and the organic peroxide and the crosslinking assistant are supplied from the first raw material supply port to the remaining rubber. Softeners are supplied from the second supply port.

It has an elliptical shape, and its rotational diameter [d
(Mm)] to the average thickness per sheet [l (m
m)], a kneading disk in which ten kneading disks having a ratio [l / d] of 0.1 are arranged orthogonally and superposed, followed by a kneading disk 5 having a ratio [l / d] of 0.1. A screw provided with a kneading section on the upstream side, in which a kneading section composed of one unit is a reverse feed type in which the sheets are stacked in the screw reverse feed direction and six units are arranged with a full flight screw therebetween. The crystalline propylene-based resin and the olefin-based rubber softener (including oil-softened rubber in the case of oil-extended rubber), and the organic peroxide and the crosslinking assistant are supplied from the first raw material supply port to the remaining rubber. Softeners are supplied from the second supply port.

An elliptical shape having a rotation diameter [d
(Mm)] to the average thickness per sheet [l (m
m)], an orthogonal type in which fifteen kneading disks having a ratio [l / d] of 0.1 are orthogonally superposed, followed by a kneading disk 5 having a ratio [l / d] of 0.1. A screw provided with a kneading section on the upstream side, in which a kneading section composed of one unit is a reverse feed type in which the sheets are stacked in the screw reverse feed direction and six units are arranged with a full flight screw therebetween. The crystalline propylene-based resin and the olefin-based rubber softener (including oil-softened rubber in the case of oil-extended rubber), and the organic peroxide and the crosslinking assistant are supplied from the first raw material supply port to the remaining rubber. Softeners are supplied from the second supply port.

It has an elliptical shape, and its rotational diameter [d
(Mm)] to the average thickness per sheet [l (m
m)], a kneading disk in which ten kneading disks having a ratio [l / d] of 0.1 are arranged orthogonally and superposed, followed by a kneading disk 5 having a ratio [l / d] of 0.1. A screw provided with a kneading section on the downstream side, in which a kneading section composed of one unit is a reverse feed type in which sheets are stacked in the screw reverse feed direction and six units are arranged with a full flight screw therebetween. Crystalline propylene resin and olefin rubber softener (including oil softener in the case of oil-extended rubber) are supplied from the first raw material supply port through an organic peroxide, a crosslinking aid, and a residual rubber. Softeners are supplied from the second supply port.

(For Comparative Example) A knee having an elliptical shape and a ratio [l / d] of an average thickness [l (mm)] per sheet to a rotation diameter [d (mm)] of 0.5 is used. A forward feeding type in which ten discs are stacked in the forward direction of the screw, and a reverse feeding in which five kneading discs having a ratio [l / d] of 0.1 are subsequently stacked in the reverse direction of the screw. A screw provided with a kneading unit on the upstream side, wherein one unit is a type and three units are provided with a full flight screw between them. The crystalline propylene-based resin and the olefin-based rubber softener (including oil-softened rubber in the case of oil-extended rubber), and the organic peroxide and the crosslinking assistant are supplied from the first raw material supply port to the remaining rubber. Softeners are supplied from the second supply port.

(For comparison) A knee having an elliptical shape and a ratio [l / d] of an average thickness [l (mm)] per sheet to a rotation diameter [d (mm)] of 0.1 is used. A progressive feeding type in which fifteen loading disks are superposed in the screw forward direction, followed by a reverse feeding in which five kneading discs having a ratio [l / d] of 0.1 are superposed in the screw reverse direction. A screw provided with a kneading section on the upstream side in which one type is a unit and six units are arranged with a full flight screw between them. The crystalline propylene-based resin and the olefin-based rubber softener (including oil-softened rubber in the case of oil-extended rubber), and the organic peroxide and the crosslinking assistant are supplied from the first raw material supply port to the remaining rubber. Softeners are supplied from the second supply port.

Examples 1 to 18 and Comparative Examples 1 to 12 A crystalline propylene resin and an olefin copolymer rubber shown in Table 1 or tetrakis as an antioxidant together with an organic peroxide and a crosslinking aid. [Methylene-3-
(3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane (“Irganox 1010” manufactured by Ciba-Geigy) and 2- as an ultraviolet absorber
(2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole (“Tinuvin 326” manufactured by Ciba Geigy) and a crystalline propylene resin and an olefin copolymer rubber. After adding 0.1 parts by weight to the total amount of 100 parts by weight and mixing with a Henschel mixer, the supply of a rubber softener was also added to a twin-screw extruder having a screw kneading section shape shown in Table 1. The olefin-based thermoplastic elastomer was produced by dynamically supplying heat under the conditions shown in Table 1 and extruding.

The numerical values of the crystalline propylene resin and the olefin copolymer rubber in Table 1 are% by weight based on the total amount of both, and the numerical value of the rubber softener is 100 wt% of the olefin copolymer rubber. Parts by weight, and the numerical values of the organic peroxide and the crosslinking assistant represent parts by weight based on 100 parts by weight of the total amount of the crystalline propylene resin and the olefin copolymer rubber.

For each of the obtained olefin-based thermoplastic elastomers, the melt flow rate and the gel fraction were measured by the methods described below, and the surface appearance was observed. The results are shown in Table 1.

Melt flow rate According to JIS K7210, temperature 230 ° C., load 5.
It was measured at 0 kg or 10.0 kg.

Gel fraction The obtained thermoplastic elastomer was subjected to Soxhlet extraction with boiling cyclohexane for 12 hours, and was calculated as an insoluble content after extraction with respect to the olefin copolymer rubber in the thermoplastic elastomer.

[0058] The thermoplastic elastomer obtained surface appearance, a barrel diameter 45 mm,
At L / D28, a melt extruded into a sheet at 220 ° C. using an extruder (manufactured by Musashino Machinery Co., Ltd.) equipped with a T die, and 30 ° C.
2m / m between the crimping roll and the pressure roll set at
By taking at a speed of one minute, crimping and cooling and solidifying, a crimped sheet having an average grain depth of 100 μm and a thickness of 0.35 mm is formed, the sheet surface is visually observed, the number of bumps is counted, and The surface appearance was evaluated according to the following criteria. A: Excellent. ；: Good. △; slightly rough. X; roughness is conspicuous.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

According to the present invention, an olefin thermoplastic elastomer is produced by dynamically heat-treating a composition of a crystalline propylene resin and an olefin copolymer rubber in the presence of an organic peroxide. In the above, it is possible to provide a method for producing an olefinic thermoplastic elastomer which can efficiently produce an olefinic thermoplastic elastomer having excellent surface appearance.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazunori Yano 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co., Ltd. Yokkaichi Office Yokkaichi Office F-term (reference) 4F201 AA03E AA11 AB03 AH26 AR09 AR14 AR20 BA01 BC01 BC12 BC38 BK02 BK13 BK27 BK49 4J002 BB05X BB12W BB14W BB14X BB15X BB17X FD010 GB01 GC00 GN00 GQ01

Claims (4)

[Claims] An olefin thermoplastic elastomer is produced by dynamically heat-treating a composition of a crystalline propylene resin and an olefin copolymer rubber in the presence of an organic peroxide. Using a twin-screw extruder with a directional or counter-rotating twin-screw,
At least at the position after the supply of the organic peroxide to the extruder, the ratio [l / d] of the average thickness per sheet [l (mm)] to the rotating diameter [d (mm)] is 0.5. A kneading unit configured to have no forward feeding ability and no reverse feeding ability is provided by a plurality of the following kneading disks, and a barrel radius [R (mm)] and a screw rotation speed [N (rpm) of the twin-screw extruder are provided. And a discharge rate [Q (kg / hour)], and extruding while maintaining the relationship of the following formula. 2.6 <(N × Q) / R ³ <22.6 2. The method for producing an olefinic thermoplastic elastomer according to claim 1, wherein the kneading section is constituted by three or more kneading disks. 3. The maximum shear rate of the kneading section is 1,000 /
3. The method for producing an olefin-based thermoplastic elastomer according to claim 1, wherein the time is not less than seconds and less than 10,000 / sec. 4. The composition of a crystalline propylene-based resin and an olefin-based copolymer rubber, wherein the composition ratio of the two is 5 to 80% by weight of the former resin and 95 to 20% by weight of the latter rubber. The method for producing an olefin-based thermoplastic elastomer according to any one of the above.