JPS62199639A - Thermoplastic elastomer composition and production thereof - Google Patents

Abstract

PURPOSE:The titled composition suitable for automobile parts, etc., having improved moldability and rubber elasticity, obtained by crosslinking latex of ethylene alpha-olefin copolymer rubber to give a crosslinked latex composition and blending the composition with a specific amount of crystalline polyolefin. CONSTITUTION:100pts.wt. ethylene alpha-olefin copolymer rubber which has 50-87mol% ethylene content, 0.5-3dl/g intrinsic viscosity and 30-95wt% hot toluene insoluble content and 2-50pts.wt. low-molecular-weight alpha-olefin copolymer and/or modified low-molecular-weight alpha-olefin copolymer are homogeneously dispersed in an aqueous medium in the presence of a surface active agent to form copolymer rubber latex, which is crosslinked in a latex state and dried to give finely divided ethylene alpha-olefin copolymer rubber having 1-10mum average particle diameter and <=20mum maximum particle diameter. The rubber is blended with a crystalline polyolefin resin in a weight ratio of 90:10-50:50 in a molten state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a Kunetcho plastic elastomer composition that has excellent moldability and rubber elasticity.

(Prior art) Thermoplastic elastomers are energy-saving and resource-saving elastomers that are particularly used as substitutes for vulcanized rubber for automobile parts (bellows, chapes, interior sheets, mudguards),
It is used in industrial machinery parts (pressure hoses, gaskets, Dia 7 rams), electronic and electrical equipment parts, building materials, etc.

Olefin-based thermoplastic elastomeric compositions comprising a blend of completely crosslinked ethylene-propylene-nonconjugated diene copolymer rubber (EPDM) and polyolefin resin are disclosed in Japanese Patent Publication No. 58-46138 and Japanese Patent Publication No. 55-1.
This is known from Japanese Patent No. 8448 and the like. Although this composition has various excellent properties, it lacks rubber elasticity and moldability, so it has certain limitations in its use as a substitute for vulcanized rubber, and improvements are needed.

(Problems to be solved) General methods for improving the rubber elasticity of olefinic thermoplastic elastomers include: 1. Crosslinking increases the amount of rubber component blended.

■ Increase the amount of process oil used as a softener.

etc. are mentioned. However, although both improve the elasticity of the thermoplastic elastomer, there is a problem in that the strength of the thermoplastic elastomer decreases.

In addition, general methods for improving the moldability of olefin thermoplastic elastomers include: (1) increasing the amount of polyolefin resin blended;

■ Increase the amount of process oil used as a softener.

etc. are mentioned. However, there is a problem in that the former causes a decrease in rubber elasticity, and the latter causes a decrease in strength.

Therefore, the object of the present invention is to provide a thermoplastic elastomer that has significantly improved moldability and rubber elasticity without impairing the excellent heat resistance, weather resistance, and mechanical properties such as strength of the olefinic thermoplastic elastomer, and a method for producing the same. Our goal is to provide the following.

(Means for Solving the Problems) In order to solve the above problems, the present invention aims to solve the problems described above.
- A latex composition obtained by finely dispersing an olefin copolymer rubber in an aqueous medium to have a particle size within a specific range to form a latex, and then crosslinking in the latex state is used as a starting material. The thermoplastic elastomer composition is obtained by blending the thermoplastic elastomer and the crystalline polyolefin resin.

The obtained thermoplastic elastomer composition contains ethylene α
- The main components are olefin copolymer rubber and crystalline polyolefin resin, with the crystalline polyolefin resin existing as a groove-shaped continuous phase and the ethylene/α-olefin copolymer rubber existing as a finely uniformly dispersed island phase. It is something to do.

(Function) That is, in the thermoplastic elastomer composition of the present invention,
Since the crystalline polyolefin resin exists as a groove-like continuous phase, it has excellent properties such as moldability, weather resistance, and impact resistance.

Furthermore, since the ethylene/α-olefin copolymer rubber component is finely and uniformly dispersed in the form of islands, it also has excellent rubber elasticity.

Furthermore, according to the present invention, in order to obtain the above-mentioned elastomer, a crosslinked latex composition in which ethylene/α-olefin copolymer rubber is finely dispersed is used as a starting material, and a crystalline polyolefin resin is blended therein. As a result, the particle size of the dispersed rubber particles can be easily adjusted in the latex preparation stage, and a desired thermoplastic elastomer can be easily obtained.

For example, when directly melt-kneading the ethylene/α-olefin copolymer 1) gum and crystalline polyolefin resin, it is difficult to adjust the particle size of the rubber particles, and it is difficult to adjust the particle size of the rubber particles to the desired particle size. It is difficult to obtain dispersed elastomer compositions.

(Effects) The thermoplastic elastomer composition of the present invention has excellent mechanical properties such as moldability, rubber elasticity, weather resistance, and strength, so it can be used for bellows, cheeseboards, interior sheets, mudguards, boots, etc. It is extremely useful in various fields such as automobile parts such as pressure hoses, gaskets, diaphragms, industrial mechanical parts such as electronic and electrical equipment parts, electric wire cables, covering materials, building materials, and footwear soles.

(Preferred Embodiment of the Invention) Elastomer Composition Constituent Component (A) Ethylene/α-olefin copolymer rubber
In addition to completely amorphous materials such as rubber,
This concept also includes polymers with a low crystallinity of 15 or less as measured by X-ray diffraction.

The ethylene/α-olefin copolymer rubber used in the present invention includes ethylene and α-olefin, such as propylene, 1-butene, 1-intene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1 It is a copolymer with 121 or more α-olefins having 3 to 10 carbon atoms such as -decene.

Its ethylene content is usually 50 to 87 ma1%, preferably 63 to 82 mo/L/thi, and its intrinsic viscosity in decahydronaphthalene solution at 135°C is 0.5 to 3.
．． Odt/11.4? K 0.7 to 1.5 clt
/fl is preferably used.

Furthermore, this ethylene/α-olefin compound rubber may contain one or more /IJene components.

Specifically, the polyene component includes 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-hecitadiene, 7-methyl-1,6 - linear non-conjugated diene such as octadiene,
Cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinyl-2-norbornene,
5-factor 7"7-2-norbornene, 5-methylene-
2-norbornene, 5-isopropylidene-2-nor〆runene, 6-chloromethyl-5-isopropenyl-2-
Cyclic non-conjugated dienes such as norbornene, 2,3-diisopropyritene-5-norgelnene, 2-ethylidene-
Typical examples include trienes such as 3-isopropylidene-5-nor〆runene, 2-f lopenyl-2,2-nor as lunadiene, and octatriene and 1,4.9-decatriene in 1.3.7. be able to. Suitable polyenes are cyclic non-conjugated dienes and 1,4-hexadiene, especially synclopentadiene or 5-ethylidene-2-norbornene.

These polyene components are copolymerized so that the resulting copolymer has an iodine value of at most 30, preferably 20 or less.

The ethylene/α-olefin copolymer rubber as described above is
For example, it can be produced by a method known per se, as described in Synthetic Rubber Processing Techniques [Ethylene Propylene 9] (Taiseisha).

That is, in a medium, ethylene,
It is produced by supplying an α-olefin having 3 to 10 carbon atoms, polyene if necessary, and hydrogen gas as a molecular weight regulator. Examples of media include aliphatic hydrocarbons such as intane, hexane, heptane, octane, and kerosene, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, chlorobenzene, and carbon tetrachloride. , tetrachloroethylene, trichlorethylene, ethyl chloride, methylene chloride, dichloroethane, and other halodanized hydrocarbons can be used alone or in combination. Examples of soluble vanadium compounds include vanadium tetrachloride, vanadyl trichloride, vanadium triacetylacetonate, vanadyl acetylacetonate, vanadyl trialkoxide VO(OR), (herein, R is an aliphatic hydrocarbon group), Halogenated panasol alkoxide VO (OR
)nX! -n (where R is an aliphatic hydrocarbon group, X is a halogen atom, and 0<n<3), etc. can be used alone or in combination of two or more. On the other hand, as an organoaluminum compound, the general formula RnIA2x3-
Compounds represented by fI, (where R is an aliphatic hydrocarbon group, X is halodane, and 1≦m≦3) such as triethylaluminum, diethylaluminium chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, etc. These can be used alone or in combination of 21 or more.

In addition, the above ethylene α in the elastomer composition of the present invention
- The olefin copolymer rubber component has a hot toluene insoluble content of 30 to 95% by weight, preferably 40 to 90% by weight.
It is important that the crosslinks are formed within the range of .

By using the ethylene/α-olefin copolymer rubber in which crosslinks are formed in this manner, a thermoplastic elastomer having particularly excellent strength and moldability can be obtained.

This hot toluene insoluble amount is an index indicating the degree of crosslinking of the rubber component, and is determined as follows.

That is, after salting out the crosslinked latex composition described below, dry ethylene/α-olefin co-produced rubber CWo9)
was extracted with a large excess of boiling toluene for 6 hours, and 0.05 μm
The value obtained by drying and weighing the residue was taken as Wl, 9, and the value was calculated using the following formula, W, /WoX 100 (wt%).

(B) Crystalline polyolefin resin The crystalline polyolefin resin used in the present invention is:
A single or copolymer of 1-olefin, which has a crystallinity of usually 4 (1 or more, preferably 60) by X-ray diffraction.
% or more. The polymerization type may be either random polymerization or block polymerization. In the case of random copolymers, those containing the smaller 1-olefin unit are usually 40 molti or less, preferably 30 molti or less.

The 1-olefins include ethylene, propylene, 1-olefin,
-butene, 1-pentene, 1-hexene, 4-methy/I
/ -1-pentene, 1-octene, 1-decene, 1-
It can be enriched with one or more of dodecene etc.

Is this crystalline again? The lyolefin resin is not limited to the above polymers or copolymers, but may also contain other olefin polymers in an amount of 40% by weight or less based on the composition.

In the present invention, among the above-mentioned crystalline polyolefin resins, isotactic I-propylene or a copolymer of propylene and a small amount of other α-olefin is used because it has excellent moldability and heat resistance and is suitable for obtaining a composition. It is preferably used in

Thermoplastic Elastomer Composition The thermoplastic elastomer composition of the present invention is composed of the above-mentioned ethylene/α-olefin copolymer rubber (A) and crystalline olefin resin CB) in a ratio of 90:10 to 50% by weight. :50, especially in a ratio of 80:20 to 60:40.

In other words, if the content of the ethylene/α-olefin copolymer comb is higher than the above range, properties such as moldability and strength will be poor, and if it is lower than the above range, the elasticity of the adhesive will be significantly reduced. do.

(9) In the elastomer composition of the present invention, the crystalline polyolefin resin is present as a groove-like continuous phase, and is made of ethylene/α-olefin copolymerized-1” mtri, and has an average particle size of 0.1 to 10 μm. Preferably, the particle size is in the range of 0.2 to 5 μm, and the particles are finely dispersed in an island shape so that the maximum particle size is 20 μm or less.

If the average particle size is less than 0.1 μm, the comb elasticity of the thermoplastic elastomer composition will be poor, and if it exceeds 10 μm, the moldability and strength will be poor.

Further, if the maximum particle size exceeds 20 μm, the thermoplastic elastomer composition becomes unsatisfactory in moldability and strength.

In the present invention, the average particle size and maximum particle size in the composition refer to values measured as follows.

An injection molded sheet with a thickness of 2 μ is freeze-cut, the cut surface is stained with osmium tetroxide, and after dyeing dispersed rubber particles, a continuous area consisting of 50 to 100 dispersed rubber particles is arbitrarily cut using an electron microscope. Select three locations, observe the long diameter and number of dispersed rubber particles at each location, calculate the number average particle diameter, and
The average value of the area was taken as the average particle size.

Region 1 Number average grain size A1 t2. t A2 t 3 t As Average particle size of dispersed rubber particles = % (A, 10 people 2 + A!S) Also, the maximum particle size of dispersed rubber particles is the maximum particle size of each observed in areas 1 and 2゜3 , ,L2. L, and its average value was taken as the average value.

That is, maximum particle size of dispersed rubber particles = % (L, +L2+L5) Also, the amount of hot toluene insoluble matter in the composition was measured as follows.

Weigh out approximately 0.5 g of thermoplastic elastomer. , 9), extracted with boiling toluene of 50αee for 6 hours, and extracted with 0
．． Filter through a 05 μm 74 filter, dry the residue, and then weigh it (defined as Wlg).

In addition, the elastomer composition of the present invention may contain mineral oil-based softeners, rubber compounding agents, etc., which are known per se, to the extent that they do not impair the strength, moldability, and rubber properties of the elastomer composition. .

Mineral oil-based softeners usually weaken the intermolecular attraction of rubber during roll processing, making processing easier, promoting the dispersion of carmen black, white carmen, etc., or reducing the hardness of vulcanized rubber. A petroleum fraction with a high boiling point that is used for the purpose of reducing flexibility and increasing comb elasticity.It is classified into rough-hewn, naphthenic, aromatic, etc.

In the present invention, /4' rough-in type process oil is particularly effectively used. Such a mineral oil softener contains 100 parts by weight of an ethylene/α-olefin copolymer,
Amounts up to 200 parts by weight may be used. If the amount exceeds this range, the strength of the resulting elastomeric composition will decrease, or the softener will ooze out, resulting in problems such as deterioration of the appearance.

In addition, compounding agents for rubber include fillers, colorants, anti-aging agents, antioxidants, cross-linking agents/cross-linking aids, secondary light or light resistance stabilizers, processing aids, antistatic agents, and other physical property improvers. can be used as appropriate.

For example, fillers include carmen black, clay, talc, heavy calcium carbonate, kaolin, diatomaceous earth, silica, alumina, asbestos, graphite, glass fiber, etc., and antioxidants include phenyl-
α-su7thylamine, p-impropoxy diphenylamine, N,N”-diphenylΦethylenediamine,
Amine-based antioxidants such as nonylated sophenylamine, 2
．． 6-diter7yarifthylphenol, styrenated phenol, butylated hydroxyanineol, 4.4'-
Hydroxydiphenyl, 2,2-methylene-bis-(4
-methyl-6-7chlorohexyl phenol), tetra-kis-[methylene-3-(3',5'-ditasha'
)-pf-4'-hydroxyphenyl)gropionate]methane, tris-(2-methyl-hydroxy-5-
Examples include phenolic antioxidants such as ditertiary-butylphenyl)butane.

In the present invention, the thermoplastic elastomer composition is prepared by preparing a latex of the ethylene/α-olefin copolymer rubber described above, crosslinking it in the latex state, and using this crosslinked latex composition as a main raw material to prepare various crystalline polyolefin resins. It is manufactured by blending in the following manner.

Latexization of ethylene/α-olefin copolymer rubber In the present invention, the average particle diameter and hot toluene insoluble content of the ethylene/α-olefin copolymer rubber can be adjusted by converting the copolymer into latex and crosslinking in the latex state. It is done by doing.

Production of ethylene/α-olefin copolymer rubber latex: For example, ethylene/α-olefin copolymer rubber is dissolved in an organic solvent such as toluene or hexane, and then emulsified in water in which a surfactant is dispersed. It can be manufactured by a method that removes the

For emulsification in water, known means and methods can be used, such as using a homomixer equipped with a high-speed stirring blade or a high-speed pipe emulsifier.

In addition, when preparing this latex, a low molecular weight α-olefin copolymer (hereinafter sometimes simply referred to as an olefin copolymer) or a modified low molecular weight α-olefin copolymer
Copolymer (hereinafter sometimes simply referred to as modified copolymer)
It is preferable to mix 2 to 50 parts by weight per 100 parts by weight of the copolymer.

These olefin copolymers and modified copolymers prevent agglomeration of rubber particles by easily making the copolymer rubber fine when converting the copolymer rubber into latex, and also prevent the agglomeration of rubber particles when forming the resulting thermoplastic elastomer. Improve your sexuality.

As this olefin copolymer, both a waxy one and a liquid one at room temperature can be used, and it is also possible to use both in combination.

(a) As the waxy copolymer, an ethylene-glopyrene copolymer and/or an ethylene-1-butene copolymer is generally used.

Copolymers useful for purposes of this invention have a density of 0.9 (1
/m or higher, and a softening point (picat) of 90°C or higher, preferably 95°C or higher.

(b) Useful liquid copolymers at 135°C
It has an intrinsic viscosity of 0.01 to 0.3 dt/9 in the state of a decahydronaphthalene solution.

These waxy or liquid copolymers can also be used as modified products containing the below-described unsaturated cargenic acid compound as a graft copolymerization component.

As the modified copolymer, a modified polyethylene wax digraft-modified with an unsaturated cargenic acid compound and a modified ethylene/α-olefin copolymer are used.

Unsaturated/I/ykenic acid compounds used as modifiers include unsaturated cargenic acids containing 3 to 10 carbon atoms, K, anhydrides thereof, amides thereof, imides thereof, and esters thereof. One or more types of acids, such as acrylic acid, methacrylic acid, maleic acid,
Fumaric acid, itaconic acid, citraconic acid, nordelene dicarzanic acid, tetrahydrophthalic acid, bicyclo(2,
2,1) Unsaturated carboxylic acids such as hept-2-ene-5,6-dicardenoic acid, maleic anhydride, itaconic anhydride,
Unsaturated carboxylic acid anhydrides such as citraconic anhydride, tetrahydrophthalic anhydride, bicyclo(2,2,1)hept-2-dyne-5,6-dicargenic acid anhydride, maleic acid monoamide, maleic acid diamide, maleimide, etc. amides or imides of , methyl acrylate, methyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconate, dimethyl tetrahyro-7talate, bicyclo(2,2 ,1) hept-2-ene-
Examples include unsaturated caldic acid esters such as dimethyl 5,6-dicarboxylate and glycidyl (meth)acrylate. Among these, preferred are maleic anhydride, maleic monoamide, maleic diamide, maleimide, monomethyl maleate, diethyl maleate, glycidyl (meth)acrylate, and the like.

Such graft copolymer component is usually 0.2 to 50 g, preferably 0.2 to 20 g, based on the weight of the modified copolymer.
Denaturation may be carried out so that the content is %.

At a content of 20% or less, there is almost no change in the softening point of the modified copolymer.

Furthermore, when a modified ethylene/α-olefin binary copolymer is used as the modified copolymer, the intrinsic viscosity of the decahydronaphthalene solution at 135°C is ODl to 0.3.
Modified copolymers with dt/9 are preferred.

Such low molecular weight α-olefin copolymers or modified low molecular weight α-olefin copolymers can be used alone or in combination, and in either case, the above-mentioned nine copolymers are 2 to 50 parts by weight, especially 5
It is preferable that the latex be contained in the range of 40 to 40 parts by weight. When used in an amount smaller than this range, it tends to become difficult to refine the polymer components when forming them into latex.

Uniform dispersion of a polymer in an aqueous medium can be achieved, for example, by dissolving the polymer in a solvent such as n-hexane, and then stirring the solution into an aqueous medium in which an appropriate amount of surfactant has been dispersed. It is recommended that the solvent be mixed and dispersed and then heated to an appropriate temperature to evaporate and remove the solvent component.

If a solvent is not used, the latex may be formed by kneading an aqueous medium containing a copolymer rubber or the like and a surfactant using an extruder or the like.

As the surfactant, any surfactant such as anionic surfactants, cationic surfactants, nonionic surfactants, etc. can be used, and anionic surfactants such as fatty acid sodium and fatty acid potassium can be preferably used. The amount of surfactant used varies depending on the type of polymer component used, but generally copolymer rubber 1
00 parts by weight! It is preferable to select a proportion of 70.2 to 20 parts by weight.

In addition, the amount of aqueous medium to be used is such that the solid content concentration in the latex is 5 to 65 w from the viewpoint of particle size adjustment of the fine particle crosslinked copolymer rubber.
It is preferable to select it so that it becomes t.

(ii) Crosslinking of Latex The ethylene/α-olefin copolymer rubber latex prepared as described above is subjected to a crosslinking reaction in a latex state.

Crosslinking is effectively carried out by blending a polyfunctional monomer into the latex and, for example, by crosslinking with an organic peroxide or with an electron beam.

As the polyfunctional monomer to be used, for example, monomers having two or more ethylenically unsaturated bonds, especially vinyl bonds, etc. are preferably used, and specific examples include divinylbenzene, tetramethylene di(meth)acrylate, glyceryl triacrylate, Ethylene glycol dimethacrylate, 1
, 2,4-trivinylcyclohexane, and tetraallyloxyethane.

This polyfunctional upper layer is based on 100 parts by weight of copolymer rubber.
It is preferable to use it in a range of 0.1 to 20 parts by weight, particularly 0.3 to 5 parts by weight.

The organic peroxide used depends on the stability of latex particles,
In view of the stability and economic efficiency of the crosslinking reaction operation, those having a 10-hour half-life temperature of 0° C. or more and 100° C. or less are preferable, and the following organic peroxides can be specifically exemplified.

1.1-bis(1-butylperoxy)fuclohexane, t-butylperoxypivalate, t-butyl/#-oxy-2-ethylhexanoate, t-butylperoquine isoprobyl carbonate, 2 .5-dimethyl-2,5-bis(tart-butylperoxy)hexene-3,2,5-dimethyl-2,5-bis(tert-butylperoxy)hexene-3,2,5-tmethyl-2,5 -bis(tert-butylperoxy)hexane, 3.5.5-trimethylhexanoylperoxide,
Benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, 1,3-bis(tert-butylperoxyinglovir)benzene, isobutyl peroxide, diisopropyl peroxydicargenate, di(2-ethylhexyl) peroxide ΦSical? acetylcyclohexylsulfonylperoxide, 1,1-bis(t-butylperoxy) -3,3゜5
-Trivinylcyclohexane.

The amount of organic peroxide used varies depending on the required degree of crosslinking, but in the present invention, it is usually 3×10 to 5× per 100 parts of ethylene/α-olefin copolymer rubber.
By using 10 mol, especially in the range of 10 to 3X10 mol, the amount insoluble in hot toluene can be adjusted within the above-mentioned range.

Further, when crosslinking with an organic peroxide, it is preferable to use a crosslinking aid in combination.

Examples of crosslinking aids include sulfur, quinone dioxime types such as p-quinone dioxime, methacrylate types such as polyethylene glycol dimethacrylate, allyl types such as diallyl phthalate and triallyl cyanurate, other maleimide types, and divinylbenzene. Illustrated. Such a crosslinking aid (vulcanization aid) is usually used in an amount of Hz to 2 moles, preferably approximately equimolar, per mole of the organic peroxide used.

These organic peroxides and crosslinking aids may be blended in advance before producing the latex, or may be blended after producing the latex.

The heating time for crosslinking is usually 5 to 1 half-life.
It is preferable to set it to 0 times, and it can be carried out either under normal pressure or under pressure.

In electron beam crosslinking, α rays, β rays, γ rays, electron beams,
The absorbed dose is selected depending on the required degree of crosslinking, but in the case of the present invention, it is usually controlled within the range of 1 to 50 Mrad, preferably 5 to 30 Mrad. . Even in such electron beam crosslinking, if a crosslinking aid is added in advance, the crosslinking efficiency can be improved.

(Ill) Drying of crosslinked ethylene/α-olefin copolymer rubber latex Methods for separating and removing the aqueous medium from the crosslinked copolymer rubber latex include spray drying, freeze drying, etc.
Known drying methods can be applied. Since the ethylene/α-olefin copolymer rubber is crosslinked in the latex state, the gum hardly aggregates during drying. Even if aggregation occurs, it is only a slight agglomeration, so it is easily finely dispersed in a melt blending operation with a crystalline polyolefin resin, which will be described later.

O fine particulate cross-linked ethylene/α-olefin joint type Co9
The thermoplastic elastomer of the present invention is produced by melt-blending the thermoplastic elastomer of the present invention with a fine cross-linked copolymer rubber obtained by drying a cross-linked copolymer rubber latex, and a crystalline polyolefin in the form of a pellet or powder. This can be carried out by melt blending the resins in a weight ratio of 90:10 to 50:50 using an internal mixer such as a Banbury mixer or a single-screw or multi-screw extruder. It is said that if the proportion of the fine particle cross-linked copolymer rubber exceeds the above upper limit, the moldability and strength of the thermoplastic elastomer will be significantly reduced, and if the proportion of the fine particle cross-linked copolymer rubber is below the above lower limit, the elasticity of the thermoplastic elastomer will be significantly reduced. causing inconvenience. The temperature during melt blending varies depending on the melting point of the crystalline polyolefin resin, but is preferably 150"C to 260"C.

In addition, this blend of crystalline polyolefin resin is obtained by mixing the polyolefin resin with an aqueous medium during the latexization of the ethylene/α-olefin copolymer comb,
After uniform dispersion, crosslinking is performed and dry melt blending is performed using the method described above, or ethylene/α-olefin 7
After the polyolefin resin is mixed with an aqueous medium and uniformly dispersed in the crosslinked latex composition of the copolymer comb, dry melt blending may be performed.

Mineral oil-based softeners and rubber compounding agents known per se are blended as necessary during melt blending in any case.

The thus obtained thermoplastic elastomer composition contains the crystalline polyolefin resin as a latent continuous phase, and the ethylene/α-olefin copolymer rubber as an island phase uniformly dispersed in fine particles. It has excellent mechanical properties such as moldability, weather resistance, and strength, as well as rubber elasticity.

(Example) Example 1 As an ethylene/α-olefin copolymer rubber, ethylene/propylene ethylidenenordelene copolymer rubber (ethylene unit content: 72 molt, polyene component: 5-
Contains ethylidecinordernene units with an iodine value of 15, 1
Intrinsic viscosity [η] in decahydronaphthalene at 35°C is 1
．． 1 tit/g, hereinafter abbreviated as EPT), and modified polyethylene wax (maleic anhydride unit content 3% by weight, density 0.
93. ! il/cc.

Softening point: 111° C.) 11y was dissolved in n-hexane 900II and stirred until homogeneous.

Next, add 5 g of potassium oleate as a surfactant to 9 g of water.
After being dispersed in 00I, the solution was mixed with the above solution for 60 minutes using a homomixer at a stirring blade rotation speed of 10,000 rpm. N-hexane was distilled off from the obtained emulsion at a temperature of 60 to 80°C to obtain a latex. To the latex thus obtained, appropriate amounts of p-dipinylbenzene and di-t-butylperoxytrimethylcyclohexane were added so as to have the hot toluene insoluble content shown in Table 1, and after sufficient dispersion, Transfer the latex to an autoclave and N
Heat at 120℃ for 2 hours under 9-G pressure in step 2 and step 3.
Crosslinked. Then, the average particle diameter and the amount of hot toluene insoluble matter were measured and shown in Table 1.

The cross-linked latex thus obtained was heated to 25,000 rpm using a disk atomizing spray dryer.
, a crosslinked latex feed rate of 10 kp/hr, a feed gas temperature of 200° C., and a gas flow rate of 87 FL 7 hr were used to obtain a fine particulate crosslinked amorphous copolymer.

Next, the fine particulate crosslinked copolymer rubber obtained by the above method,
VFR (230℃, 2.16k&) IIN/10
m1n.

Polypropylene having a density of 0.91 g/ce was melt-mixed in an extruder at an extrusion temperature of 230° C. so that the weight ratio of copolymer rubber and propylene was 70:30 to form pellets.

This thermoplastic elastomer was injection molded at an injection temperature of 240° C. to form a sheet with a thickness of 211 mm, and various physical properties were measured.

Formability MFR (5″Q10kf), 9/10 minutes ASTM
D-1238 Rubber elasticity P8 * (100% strain applied)
JISK6301 strength TBkg/2'17f
The JISK6301 results are shown in Table 1.

Example 2 EPT70,9. with [η] of 0.8 dt/i. 30 g of polypropylene and 21 fi of modified polyethylene wax
The same procedure as in Example 1 was carried out except that the solution was dissolved in n-hexane.

Example 3 A crosslinked copolymer rubber latex produced in the same manner as in Example 1 using EP'r with [η] of 1.3 dt/I was subjected to Example 1 in the same manner as in Example 1. The polypropylene latex produced by replacing polypropylene 10 (L with copolymer rubber 100I) used in 1 and dispersing it in an aqueous medium was mixed so that the weight ratio of copolymer rubber and propylene was 70:30, and then mixed with an aqueous medium. The same procedure as in Example 1 was carried out except that the sample was removed by drying.

Each was carried out in the same manner as in Example 1 except for the following points.

11 Comparative Example 1 The weight ratio of EPT and polypropylene used in Example 1 was 7.
After kneading for 5 minutes in a Banbury mixer at 0:30, mix EPT and polyglopylene mixture 1 using a Brabender mixer.
00 parts by weight, 0.00 parts by weight of dicumyl/4'-oxide.
2 parts by weight of divinylbenzene, 0.2 parts by weight of divinylbenzene, dynamic crosslinking blending was carried out for 7 minutes at an oil bath temperature of 180°C and a rotation speed of 6 Orpm to produce a thermoplastic elastomer, which was molded to determine its physical properties. was measured.

Comparative Example 2 Comparative Example 2 was carried out in the same manner as Comparative Example 2, except that the Bra Pender rotation speed was changed to 15 Orpm.

Comparative example 3.4.5.6 Each was carried out in the same manner as in Example 1 except for the following points.

Amount of mixture

Claims (3)

[Claims] (1) Thermoplastic elastomer composition containing ethylene/α-olefin copolymer rubber (A) and crystalline polyolefin resin (B) in a ratio of A:B = 90:10 to 50:50 on a weight basis The ethylene/α-olefin copolymer rubber (A) has an amount insoluble in hot toluene in the range of 30 to 95% by weight, and has an average particle size of 0% in the thermoplastic elastomer composition.
．． A thermoplastic elastomer composition characterized in that it exists in the form of dispersed fine particles having a maximum particle diameter of 1 to 10 μm and a maximum particle size of 20 μm or less. (2) Said ethylene/α-olefin copolymer rubber 100
Low molecular weight α-
The thermoplastic elastomer composition according to claim 1, which contains an olefin copolymer and/or a modified low molecular weight α-olefin copolymer. (3) Ethylene α whose intrinsic viscosity of decahydronaphthalene solution at 135°C is in the range of 0.5 to 3.0 dl/g.
- Olefin copolymer rubber and low molecular weight α-olefin copolymer and/or modified low molecular weight α-olefin copolymer are uniformly dispersed in an aqueous medium in the presence of (i) a surfactant and copolymerized; forming a rubber latex, (ii) performing crosslinking in the latex state to form a crosslinked rubber latex composition, (iii) drying the crosslinked rubber latex composition, and forming the resulting fine particulate crosslinked ethylene/α-olefin copolymer. A method for producing a thermoplastic elastomer comprising melt blending a rubber and a crystalline polyolefin resin, the crystalline polyolefin resin being premixed or crosslinked in step (i) of forming the copolymerized rubber latex. In the rubber latex forming step (1), the crystalline polyolefin resin dispersed in the form of fine particles in an aqueous medium is mixed in advance with the crosslinked rubber latex composition together with the aqueous medium, or the fine particulate crosslinked ethylene α- A method for producing a thermoplastic elastomer, characterized by mixing it with an olefin copolymer rubber and performing melt blending.