JP4676382B2 - Thermoplastic elastomer composition for tube or hose - Google Patents

Description

  The present invention relates to a thermoplastic elastomer composition for a tube or hose, and in particular, a thermoplastic elastomer composition for a tube or hose excellent in kink properties, extrusion moldability, and multilayer extrusion moldability in a thin molded article, and food, medical, automobile, The present invention relates to an industrial tube or hose member.

  In recent years, thermoplastic elastomers, which are soft materials with rubber elasticity and do not require a vulcanization process, can be molded and processed like thermoplastic resins, and can be recycled. Automotive elastomers, home appliance parts, wire coatings, medical use Widely used in the fields of parts, footwear, sundries, etc.

  Among thermoplastic elastomers, polystyrene-based thermoplastic elastomers such as styrene-butadiene block polymer (SBS) and styrene-isoprene block polymer (SIS), which are block copolymers of aromatic vinyl compound-conjugated diene compound, are flexible. The thermoplastic elastomer composition that is rich and has good rubber elasticity at normal temperature and has excellent processability is widely used as a substitute for vulcanized rubber.

  In addition, an elastomer composition obtained by hydrogenating an intramolecular double bond of a block copolymer of styrene and a conjugated diene in these elastomers is further improved as an elastomer having improved heat aging resistance (thermal stability) and weather resistance. Widely used.

  However, thermoplastic elastomer compositions using these hydrogenated block copolymers still have problems with rubber-like properties such as oil resistance, heat-press deformation rate (compression set) and rubber elasticity at high temperatures. In order to improve this point, a crosslinked product obtained by crosslinking a composition containing a hydrogenated derivative of the block copolymer has been proposed (for example, Patent Documents 1 to 5).

  Moreover, the crosslinked composition of the hydrogenated block copolymer disclosed in the above patent document has a problem that the compression set is still insufficient at a high temperature, particularly at 100 ° C., and the mechanical strength tends to decrease. The current level of performance has not reached the performance level required for vulcanized rubber applications. In extrusion molding, the shape retention is deteriorated due to low melt tension at high temperature, and there are many problems on the molding surface such as a longer molding cycle in injection molding.

Furthermore, any of the compositions disclosed in the above-mentioned patent documents can be used for food, medicine, automobiles, industrial hoses or tubes, especially in the case of thin molded products (for example, tubes having an inner diameter of about 5 mm and an outer diameter of about 8 mm). The present condition is inferior in kink properties (not easy to bend during bending and twisting), extrusion moldability, and multilayer extrusion moldability.
JP 59-6236 A JP-A 63-57662 Japanese Patent Publication No. 3-49927 Japanese Patent Publication No. 3-11291 Japanese Patent Publication No. 6-13628

  In view of the above problems, an object of the present invention is to provide a thermoplastic elastomer composition for food, medical, automobile, industrial hose, and tube member that is excellent in kink properties, extrusion moldability, and multilayer extrusion moldability.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have obtained a kink property, an extrusion property by subjecting a specific olefin copolymer rubber and a peroxide-decomposable olefin resin to a predetermined amount. It was found that the moldability and multilayer extrusion moldability were excellent, and the present invention was completed.

The invention described in claim 1 includes (a) 100 parts by weight of an ethylene-propylene-nonconjugated diene copolymer rubber having a crystallinity of 1% by weight or less, and (b) a peroxide-decomposable olefin resin 15 to 150. A thermoplastic elastomer composition for tubes or hoses obtained by melt-kneading a composition containing parts by weight and (c) 0.01 to 3 parts by weight of an organic peroxide.
The invention according to claim 2 is the tube or hose according to claim 1, wherein (a) the ethylene-propylene-nonconjugated diene copolymer rubber has an ethylene content of 40 to 70% by weight. It is a thermoplastic elastomer composition.
The invention described in claim 3 further comprises (d) a melt-kneading treatment of a composition containing 0.01 to 10 parts by weight of an ester-based crosslinking aid. This is a thermoplastic elastomer composition for tubes or hoses.
The invention according to claim 4 is the thermoplastic elastomer for tubes or hoses according to claim 3, wherein (d) the ester-based crosslinking aid is a polyfunctional acrylate compound or a polyfunctional methacrylate compound. It is a composition.
The invention according to claim 5 further comprises (e) 1 to 150 parts by weight of an inorganic filler, The thermoplastic elastomer for a tube or hose according to any one of claims 1 to 4 It is a composition.
The invention described in claim 6 further comprises (f) 1 to 100 parts by weight of a conjugated diene copolymer and / or a hydrogenated conjugated diene copolymer. The thermoplastic elastomer composition for a tube or hose according to any one of the above.
The invention according to claim 7 further comprises (g) 1 to 100 parts by weight of a non-aromatic rubber softener, or the tube according to any one of claims 1 to 6, It is a thermoplastic elastomer composition for hoses.
Invention of Claim 8 is the tube and hose member which shape | molded the thermoplastic elastomer composition for tubes or hoses of any one of Claims 1-7.

  Since the thermoplastic elastomer composition of the present invention is excellent in kink properties, extrusion moldability, and multilayer extrusion moldability, it can be used in food, medical, automobile, industrial tubes and hose members.

  The components, production methods, and uses constituting the present invention will be described in detail below.

1. Component of thermoplastic elastomer composition (1) Olefin copolymer rubber component (a)
The olefin copolymer rubber component (a) used in the thermoplastic elastomer composition for a tube or hose of the present invention is an elastomer obtained by copolymerizing an α-olefin such as ethylene, propylene, 1-butene, 1-pentene or the like. Examples thereof include olefin copolymer rubbers obtained by copolymerizing these with non-conjugated dienes.

  Examples of non-conjugated dienes include dicyclopentadiene, 1,4-hexadiene, dicyclooctadiene, methylene norbornene, and 5-ethylidene-2-norbornene.

  Specific examples of such olefin copolymer rubber include ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene copolymer rubber, ethylene-1-butene copolymer rubber, and ethylene-1. Examples thereof include ethylene copolymer rubbers such as -butene-nonconjugated diene copolymer rubber and ethylene-propylene-1-butene copolymer rubber.

  The ethylene content in the ethylene copolymer rubber is preferably 40 to 70% by weight, more preferably 45 to 65% by weight. When the ethylene content is less than 40% by weight, the mechanical properties and heat resistance are remarkably lowered, and when it exceeds 70% by weight, the flexibility is lost and the rubber elasticity becomes remarkable and the kink property is deteriorated.

  Further, the crystallinity of polyethylene as measured by DSC of the olefin copolymer rubber (a) is preferably 20% by weight or less, more preferably 15% by weight or less, and further preferably 1% by weight or less. When the degree of crystallinity exceeds 20% by weight, the flexibility of the resulting tube or hose thermoplastic elastomer composition decreases, the hardness of the thermoplastic elastomer composition becomes too high, and the flexibility is lost, resulting in a rubbery feel. I can't get the product.

Here, the crystallinity is a value obtained by the following measurement method.
(I) The sample is put in an aluminum pan with a known weight and dried under a pressure of 100 Pa or less for 24 hours before sealing.
(Ii) Immediately after drying, the weight of the entire sample container is measured and sealed under pressure.
(Iii) A sample container is set in the sample holder of the DSC, and the temperature is increased to 230 ° C. at a temperature increase rate of 10 ° C./min.
(Iv) Maintain at 230 ° C. for 60 minutes to completely melt or relax the sample.
(V) Cool to 30 ° C. at the same rate (10 ° C./min) as the temperature rising rate.
(Vi) The degree of crystallinity is evaluated from the heat of crystallization (ΔHc) on the assumption that the completeness of crystals generated in the isothermal crystallization process is constant regardless of the crystal generation time.
(Vii) The degree of crystallinity is expressed in terms of weight% of the crystallization heat (ΔHc) of the olefin copolymer rubber (a) with the crystallization heat (ΔHc) of HDPE (HJ560: Nippon Polychem, specific gravity 0.964) being 100. To do.

(2) Peroxide-decomposable olefin resin component (b)
The peroxide-decomposable olefin-based resin component (b) used in the thermoplastic elastomer composition for tubes or hoses of the present invention improves the rubber dispersion of the resulting thermoplastic elastomer composition and improves the appearance of the molded product. In addition, it has an effect on adjusting the hardness and shrinkage rate. Component (b) is an olefin-based polymer or copolymer that is thermally decomposed by heat treatment in the presence of peroxide to moderately reduce the molecular weight and increase fluidity at the time of melting. Examples thereof include copolymers of tactic polypropylene and propylene with other α-olefins such as ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene.

  The melting point by DSC measurement of the homopolymer portion of the olefin copolymer is preferably in the range of Tm of 150 to 167 ° C. and ΔHm of 25 to 83 mJ / mg. The crystallinity can be estimated from Tm and ΔHm of DSC measurement. When Tm and ΔHm are outside the above ranges, the oil resistance of the resulting thermoplastic elastomer composition and the rubber elasticity at 100 ° C. or higher are not improved.

  The melt flow rate (MFR, ASTM D-1238, L condition, 230 ° C.) of component (b) is preferably 0.1 to 200 g / 10 minutes, more preferably 0.5 to 100 g / 10 minutes. . When the MFR is less than 0.1 g / 10 minutes, the moldability of the resulting thermoplastic elastomer composition deteriorates, and when it exceeds 200 g / 10 minutes, the mechanical strength of the obtained thermoplastic elastomer composition decreases.

  The compounding quantity of a component (b) is 15-150 weight part with respect to 100 weight part of component (a), Preferably it is 40-100 weight part. If the blending amount is less than 15 parts by weight, the moldability of the resulting thermoplastic elastomer composition is deteriorated, and peeling, deformation and flow marks are likely to occur in the molded product. If it exceeds 150 parts by weight, the hardness of the thermoplastic elastomer composition becomes too high and the flexibility is lost, so that a rubber-like product cannot be obtained.

(3) Organic peroxide component (c)
In the thermoplastic elastomer composition for tubes or hoses of the present invention, an organic peroxide component (c) can be blended as necessary. Component (c) has the function of generating radicals and reacting the radicals in a chain manner to crosslink component (a). At the same time, component (b) is decomposed and the composition flows during melt-kneading. To improve the dispersion of the rubber component.

  Examples of the component (c) include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2. , 5-Di- (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3, 3,5- Trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert- Butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroylpa Oxide, tert- butyl cumyl peroxide, and the like. Of these, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di, from the viewpoint of odor, colorability, and scorch safety. -(Tert-Butylperoxy) hexyne-3 is particularly preferred.

  When blended, the amount of component (c) is preferably 0.01 to 3 parts by weight, more preferably 0.01 to 1 part by weight with respect to 100 parts by weight of component (a). If the blending amount is less than 0.01 parts by weight, the effect of addition is not observed. On the other hand, if it exceeds 3 parts by weight, the moldability becomes worse.

(4) Ester-based crosslinking aid component (d)
In the thermoplastic elastomer composition for a tube or hose of the present invention, an ester-based crosslinking aid component (d) can be blended as necessary. The component (d) has an effect of causing a uniform and efficient crosslinking reaction in the crosslinking treatment with the organic peroxide (c).

  Examples of the component (d) include triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate having 9 to 14 repeating units of ethylene glycol. , Trimethylolpropane trimethacrylate, allyl methacrylate, polyfunctional methacrylate compounds such as 2-methyl-1,8-octanediol dimethacrylate, 1,9-nonanediol dimethacrylate, polyethylene glycol diacrylate, 1,6-hexane Multifunctional acrylates such as diol diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate Compounds, may contain a polyfunctional vinyl compounds such as vinyl butyrate or vinyl stearate. You may use these individually or in combination of 2 or more types. Of the above-mentioned crosslinking aids, polyfunctional acrylate compounds or polyfunctional methacrylate compounds are preferred, and triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate are particularly preferred. The compound is easy to handle, has an organic peroxide solubilizing action, and acts as a dispersion aid for the organic peroxide, so that it is uniformly and effectively crosslinked by heat treatment, resulting in hardness and rubber elasticity. Can be obtained.

  When blended, the amount of component (d) is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 2 parts by weight, per 100 parts by weight of component (a). If the blending amount is less than 0.01 parts by weight, the effect of addition is not observed. On the other hand, if it exceeds 10 parts by weight, the moldability becomes worse.

(5) Inorganic filler component (e)
In the thermoplastic elastomer composition for a tube or hose of the present invention, an inorganic filler component (e) can be blended as necessary. In addition to the effect of improving some physical properties such as compression set of a molded article obtained from the thermoplastic elastomer composition, the component (e) has an economic advantage due to the increase in the amount.

  As component (e), chlorite, wollastonite, calcium carbonate, talc, silica, diatomaceous earth, barium sulfate, magnesium carbonate, magnesium hydroxide, mica, clay, titanium oxide, carbon black, glass fiber, hollow glass balloon, Examples thereof include carbon fiber, calcium titanate fiber, natural silicic acid, and synthetic silicic acid (white carbon). Of these, wollastonite, chlorite, calcium carbonate, talc and mica are particularly preferable, and wollastonite and mica are more preferable.

  When blended, the amount of component (e) is preferably 1 to 150 parts by weight, more preferably 20 to 110 parts by weight, per 100 parts by weight of component (a). When the blending amount exceeds 150 parts by weight, the mechanical strength of the resulting elastomer composition is remarkably lowered, the hardness is increased, the flexibility is lost, and a rubber-like product cannot be obtained.

(6) Conjugated diene copolymer and / or hydrogenated conjugated diene copolymer component (f)
In the thermoplastic elastomer composition for a tube or hose of the present invention, a conjugated diene copolymer and / or a hydrogenated conjugated diene copolymer component (f) can be blended as necessary. Component (f) is a conjugated diene copolymer and a copolymer obtained by hydrogenating or partially hydrogenating a conjugated diene-based part in the conjugated polymer, and the following (f-1) to (f) (F-3) A component is mentioned.

(F-1) Aromatic vinyl compound-conjugated diene compound random copolymer and / or hydrogenated product thereof As the aromatic vinyl compound-conjugated diene compound random copolymer used in the present invention, a conjugated diene compound and aromatic vinyl are used. Random copolymer with compound, number average molecular weight is preferably 5,000 to 1,000,000, more preferably 10,000 to 350,000, polydispersity (Mw / Mn) And the vinyl bond content such as 1,2 bond or 3,4 bond of the conjugated diene part is 5% or more, preferably 20-90%. If it is less than 5%, the feel of the molded product obtained becomes hard and does not meet the object of the present invention. Here, content of the aromatic vinyl compound which comprises a component (f-1) is 50 weight% or less, Preferably, it is 5-35 weight%. If it exceeds 50% by weight, the feel of the molded product obtained becomes hard and does not meet the object of the present invention.

  Examples of the aromatic vinyl compound in the component (f-1) include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p. -One or more types can be selected from aminoethylstyrene, vinyltoluene, p-tert-butylstyrene, etc. Among them, styrene is preferable. Further, as the conjugated diene compound, for example, one or two or more kinds are selected from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., among which butadiene, isoprene and These combinations are preferred.

  The aromatic vinyl compound and the conjugated diene compound are randomly bonded, and Korsov [I. M.M. Kolthoff, J. et al. Polymer Sci. , Vol 1p. 429 (1946)], the content of the block-like aromatic vinyl compound is preferably 10% by weight or less, preferably 5% by weight or less in the total bonded aromatic vinyl compound. Further, the hydrogenated product of the copolymer is preferably one in which at least 90% of the aliphatic double bond based on the conjugated diene compound is hydrogenated.

  Specific examples of the component (f-1) include a styrene / butadiene random copolymer (SBR) and a hydrogenated styrene / butadiene random copolymer (HSBR). In the present invention, SBR and HSBR may be used alone, or two or more kinds may be mixed and used.

(F-2) Aromatic vinyl compound-conjugated diene compound block copolymer and / or its hydrogenated component (f-2) includes at least two polymer blocks A mainly composed of an aromatic vinyl compound; A block copolymer comprising at least one polymer block B mainly composed of a conjugated diene compound and a hydrogenated block copolymer obtained by hydrogenating the block copolymer. For example, a block copolymer of an aromatic vinyl compound-conjugated diene compound having a structure such as ABA, BABA, ABBABA, and the hydrogenated block copolymer thereof. It is a coalescence.

  The (hydrogenated) block copolymer (hereinafter, (hydrogenated) block copolymer means a block copolymer and / or a hydrogenated block copolymer) is an aromatic vinyl compound. 5 to 60% by weight, preferably 20 to 50% by weight.

  The polymer block A mainly composed of an aromatic vinyl compound is preferably composed of an aromatic vinyl compound alone or a conjugated diene containing 50% by weight or more, preferably 70% by weight or more (hydrogenated) of the aromatic vinyl compound. The compound (hereinafter referred to as (hydrogenated) conjugated diene compound means a copolymer block with a conjugated diene compound and / or a hydrogenated conjugated diene compound).

  The polymer block B mainly composed of (hydrogenated) conjugated diene compound is preferably composed only of (hydrogenated) conjugated diene compound or 50% by weight or more of (hydrogenated) conjugated diene compound, Preferably, it is a copolymer block of 70% by weight or more and an aromatic vinyl compound.

  In each of the polymer block A mainly composed of these aromatic vinyl compounds and the polymer block B mainly composed of (hydrogenated) conjugated diene compound, the aromatic vinyl compound in the molecular chain or (hydrogenated) ) The distribution of the conjugated diene compound may be random, tapered (in which the monomer component increases or decreases along the molecular chain), partially blocked, or any combination thereof.

  When there are two or more polymer blocks A mainly composed of aromatic vinyl compounds or polymer blocks B mainly composed of (hydrogenated) conjugated diene compounds, they have different structures even if each has the same structure. There may be.

  As the aromatic vinyl compound constituting the (hydrogenated) block copolymer, for example, one or more kinds are selected from styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, etc. Styrene is preferred. Further, as the conjugated diene compound, for example, one or more kinds are selected from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., among which butadiene, isoprene, and these The combination of is preferable.

  The micro bond in the polymer block B mainly composed of the conjugated diene compound can be selected arbitrarily. In the butadiene block, the 1,2-microstructure has a lower limit of 1% or more, preferably 5% or more, more preferably 10% or more, and an upper limit of 95% or less, preferably 80% or less, more preferably 75% or less. is there.

  The hydrogenation ratio of the component (f-2) in the hydrogenated block copolymer can be arbitrarily selected, and in the case of improving the heat deterioration resistance while maintaining the characteristics of the unhydrogenated block copolymer. The lower limit of the conjugated diene-based aliphatic double bond is 3% or more, preferably 5% or more, more preferably 7 or more, still more preferably 9% or more, and the upper limit is less than 85%, preferably less than 80%, It is preferable to hydrogenate less than 75%, still more preferably less than 60%. Further, the 1,2-vinyl bond after hydrogenation is preferably 0.5 to 12%, more preferably less than 10%, still more preferably 5% or less, and still more preferably 3% or less.

  Further, when improving the heat deterioration resistance and the weather resistance, it is recommended to hydrogenate 80% or more, preferably 90% or more. In the polyisoprene block, 70 to 100% by weight of the isoprene compound has a 1,4-microstructure, and at least 90% of the aliphatic double bonds based on the isoprene compound are hydrogenated. preferable.

  The weight average molecular weight of the hydrogenated block copolymer provided for the present invention having the above structure is preferably 5,000 to 1,500,000, more preferably 10,000 to 550,000, and still more preferably 50,000. The range is from 000 to 400,000. The molecular weight distribution (ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn)) is preferably 10 or less, more preferably 5 or less, and more preferably 2 or less. The molecular structure of the hydrogenated block copolymer may be linear, branched, radial, or any combination thereof. In addition, the molecular weight in this invention is the value calculated | required on the basis of the polystyrene whose molecular weight is known by GPC. Therefore, the value is a relative value, not an absolute value, and may vary by about ± 30% depending on GPC conditions such as a reference sample, apparatus, and data processing method.

  The range of the solution viscosity of the block copolymer (5% toluene solution, 77 ° F., ASTM D-2196) is preferably 5 to 500 cps, more preferably 20 to 300 cps.

  Many methods for producing these block copolymers have been proposed. As typical methods, for example, a lithium catalyst or a Ziegler-type catalyst can be prepared by the method described in Japanese Patent Publication No. 40-23798. Can be obtained by block polymerization in an inert solvent. A hydrogenated block copolymer is obtained by hydrogenating the block copolymer obtained by the above method in the presence of a hydrogenation catalyst in an inert solvent.

  Specific examples of the above (hydrogenated) block copolymer include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene butene-styrene copolymer ( SEBS), styrene-ethylene / propylene-styrene copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene copolymer (SEEPS), partially hydrogenated styrene-butadiene-styrene copolymer (SBBS), and the like. be able to. In the present invention, the (hydrogenated) block copolymer may be used alone or in admixture of two or more.

(F-3) Conjugated diene compound block copolymer and / or hydrogenated product thereof As the conjugated diene compound block copolymer and / or hydrogenated product thereof used in the present invention, for example, a block copolymer of butadiene, butadiene And a block copolymer (CEBC) having a crystalline ethylene block and an amorphous ethylene-butene block obtained by hydrogenating the block copolymer. In the present invention, the conjugated diene compound block copolymer and / or the hydrogenated product thereof may be used alone or in admixture of two or more.

  When blended, the amount of component (f) is 1 to 100 parts by weight, preferably 1 to 40 parts by weight per 100 parts by weight of component (a). When the blending amount is less than 1 part by weight, there is no improvement effect, and when it exceeds 100 parts by weight, rubber elasticity is developed and kink properties are lowered.

(7) Non-aromatic rubber softener component (g)
In the thermoplastic elastomer composition for a tube or hose of the present invention, a softener component (g) for non-aromatic rubber can be blended as necessary. Examples of component (g) include non-aromatic mineral oils or liquid or low molecular weight synthetic softeners. The mineral oil softener used for rubber is a mixture of the aromatic ring, naphthene ring, and paraffin chain, and the paraffin chain carbon number accounts for 50% or more of the total carbon number. A naphthene ring having 30 to 40% carbon atoms is distinguished by being called a naphthene type, and those having 30% or more aromatic carbon number being called aromatic.

  The mineral oil-based rubber softener used as the component (g) of the present invention is classified into paraffinic and naphthenic ones. Aromatic softeners are not preferred because the component (a) becomes soluble by use of the aromatic softener, inhibits the crosslinking reaction, and cannot improve the physical properties of the resulting composition. As the component (g), paraffin-based ones are preferable, and paraffin-based ones having few aromatic ring components are particularly suitable. Examples of the liquid or low molecular weight synthetic softener include polybutene, hydrogenated polybutene, and low molecular weight polyisobutylene.

  These non-aromatic rubber softeners have a dynamic viscosity of 20 to 50000 cSt at 37.8 ° C, a dynamic viscosity of 5 to 1500 cSt at 100 ° C, a pour point of -10 to -15 ° C, and a flash point. It is preferable that (COC) shows 170-300 degreeC. Furthermore, a thing with a weight average molecular weight of 100-2,000 is preferable.

  The amount of component (g) is 1 to 100 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of component (a) when blended. If the blending amount is less than 1 part by weight, there is no improvement effect, and if it exceeds 100 parts by weight, the softening agent tends to bleed out from the resulting thermoplastic elastomer composition, and peeling, deformation and flow marks are likely to occur in the molded product. .

(8) Other ingredients (h)
In addition, in the thermoplastic elastomer composition for a tube or hose of the present invention, in addition to the above-described components, various anti-blocking agents, sealability improvers, heat stabilizers, antioxidants, light, and the like as necessary. It is also possible to contain a stabilizer, an ultraviolet absorber, a lubricant, a crystal nucleating agent, a colorant and the like. Here, examples of the antioxidant include 2,6-di-tert-p-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butylphenol, 4 , 4-dihydroxydiphenyl, tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, and the like, phenolic antioxidants, phosphite antioxidants, thioether antioxidants, and the like. Of these, phenolic antioxidants and phosphite antioxidants are particularly preferred. The antioxidant is preferably 0 to 3.0 parts by weight, particularly preferably 0.1 to 1.0 parts by weight, based on 100 parts by weight of the total of the components (a) to (g).

2. Production of Thermoplastic Elastomer Composition The thermoplastic elastomer composition for a tube or hose of the present invention is prepared by adding the above components (a) to (b) or components (c) to (g) as necessary. Can be produced by melting and kneading them simultaneously or in any order.

  The method of melt kneading is not particularly limited, and generally known methods can be used. For example, a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, or various kneaders can be used. For example, the above operation can be continuously performed by using a suitable L / D twin screw extruder, Banbury mixer, pressure kneader, or the like. Here, the temperature of melt kneading is preferably 160 to 220 ° C.

  The thermoplastic elastomer composition of the present invention obtained as described above is excellent in kink properties, extrudability, and multilayer extrusion moldability. Here, the kink property refers to the resistance to bending during twisting and twisting.For example, both ends of a tube obtained by extrusion molding are fixed to a jig of a tensile tester, and compressed at a constant speed. It can be evaluated by a value expressed by a kink test that observes the state of deformation that occurs.

3. Use of Thermoplastic Elastomer Composition When the thermoplastic elastomer composition of the present invention is formed into a tube or a hose by extrusion molding or the like, since it is excellent in kink property and extrusion moldability, an excellent hose and tube member can be obtained. In particular, hoses and tubes that can be used as food, medical, automobile, and industrial hoses and tube members, and hoses or tubes that do not undergo organic peroxide treatment can be used for medical purposes.

  The present invention will be specifically described with reference to the following examples and comparative examples, but the present invention is not limited to these examples. In addition, the measuring method and sample of the physical property used by this invention are shown below.

1. Physical property measurement method (1) Specific gravity: Measurement was performed in accordance with JIS K 7112.
(2) Hardness: In accordance with JIS K 6253, a 6.3 mm thick press sheet was used as the test piece.
(3) Tensile strength: In accordance with JIS K 6251, the test piece was a 1 mm thick press sheet punched into a No. 3 shape with a dumbbell. The tensile speed was 500 mm / min.
(4) 100% elongation stress: In accordance with JIS K 6251, the test piece was a 1 mm thick press sheet punched into a No. 3 shape with a dumbbell. The tensile speed was 500 mm / min.
(5) Elongation at break: In accordance with JIS K 6251, the test piece was a 1 mm thick press sheet punched into a No. 3 shape with a dumbbell. The tensile speed was 500 mm / min.
(6) Compression set (CS%): In accordance with JIS K 6262, a 6.3 mm thick press sheet was used as the test piece. The measurement was performed at 100 ° C. × 22 hours under the condition of 25% deformation.
(7) Extrudability: A tube having an inner diameter of 5 mm, an outer diameter of 8 mm, and a wall thickness of 1.5 mm using a 40 mm extruder (YE40 manufactured by Yamaguchi Seisakusho Co., Ltd.), cylinder temperature 160 to 180 ° C., die head and crosshead temperature Molding was performed at 185 ° C., a full flight screw, and a screw rotation speed of 40 rpm, and the drawdown property, surface appearance and shape were observed and evaluated according to the following criteria.
○: Good, △: Some grease, drawdown but good appearance, ×: Bad (8) Kink property: Set both ends of tube 200mm obtained in (7) to jig of tensile tester with jig interval 200mm Then, it was compressed at a compression rate of 100 mm / min, the presence or absence of kink was visually observed, and evaluated according to the following criteria.
○: Good (no kinking even when the jig interval is 0 mm)
×: Bad (kink occurrence)

2. Samples used in Examples and Comparative Examples (1) Olefin copolymer rubber (a): Nordel IP 4520 (EPDM; manufactured by Dupont Dow Elastomers)
Ethylene content: 50% by weight, crystallinity: 1% by weight or less (2) Peroxide-decomposable polypropylene component (b): PP-BC8 (trademark; manufactured by Nippon Polychem Co., Ltd.), crystallinity: Tm 166 ° C., Δ Hm82 mJ / mg, MFR 1.8 g / 10 min (3) Organic peroxide component (c): Perhexa 25B (trademark; manufactured by NOF Corporation)
(4) Crosslinking assistant component (d): TMPT (Trimethylol Propane Trimethylacrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.) Molecular weight: 338
(5) Calcium carbonate component (e-1): NS400 (trademark; manufactured by Sankyo Seiko Co., Ltd.)
(6) Wollastonite component (e-2): NYGLOS8 (trademark; manufactured by NYCO Minerals, Inc.), average fiber length 136 μm, average particle diameter 8 μm
(7) Chlorite component (e-3): CR330 (trademark; manufactured by Sankyo Seiko Co., Ltd.)
(8) SBS block copolymer component (f): VECTOR 2518 (trademark; manufactured by DEXCO POLYMERS) Styrene content: 30 wt% solution viscosity 75 cps (5% toluene solution, 77 ° F., ASTM D-2196)
(9) Softener component (g): Diana Process Oil PW-90 (trademark; manufactured by Idemitsu Kosan Co., Ltd.)
(10) Hindered phenol / phosphite / lactone composite antioxidant component (h): HP2215 (trademark; manufactured by Ciba Specialty Chemicals)

Examples 1-5 and Comparative Examples 1-2
Using each component in the amount shown in Table 1, the mixture was put into a twin screw extruder having an L / D of 47, and melt kneaded at a kneading temperature of 180 ° C. and a screw rotation speed of 350 rpm to be pelletized. Next, the obtained pellet was injection-molded to prepare a test piece, which was used for each test. The evaluation results are shown in Table 1. Examples 4 and 5 are reference examples.

As is clear from Table 1, Examples 1 to 3 are the thermoplastic elastomer compositions of the present invention. The thermoplastic elastomer composition had shifted also showed good properties.

  On the other hand, in Comparative Examples 1 and 2, the amount of component (b) is outside the scope of the present invention. When there are few components (b), mechanical characteristics will fall and kink property and moldability will deteriorate. When there are many components (b), it will become hard too much and kink property and extrusion moldability will deteriorate.

Claims (8)

(A) 100 parts by weight of ethylene-propylene-nonconjugated diene copolymer rubber having a crystallinity of 1% by weight or less, (b) 15 to 150 parts by weight of peroxide-decomposable olefin resin, and (c) organic peroxidation A thermoplastic elastomer composition for tubes or hoses, which is obtained by melt-kneading a composition containing 0.01 to 3 parts by weight of a product. 2. The thermoplastic elastomer composition for a tube or hose according to claim 1, wherein the ethylene-propylene-nonconjugated diene copolymer rubber has an ethylene content of 40 to 70% by weight.   The thermoplastic elastomer composition for a tube or hose according to claim 1 or 2, further comprising (d) a melt-kneading treatment of a composition containing 0.01 to 10 parts by weight of an ester-based crosslinking aid. object.   The thermoplastic elastomer composition for tubes or hoses according to claim 3, wherein (d) the ester-based crosslinking aid is a polyfunctional acrylate compound or a polyfunctional methacrylate compound.   Furthermore, (e) 1-150 weight part of inorganic fillers are contained, The thermoplastic elastomer composition for tubes or hoses of any one of Claims 1-4 characterized by the above-mentioned.   The tube according to any one of claims 1 to 5, further comprising (f) 1 to 100 parts by weight of a conjugated diene copolymer and / or a hydrogenated conjugated diene copolymer. A thermoplastic elastomer composition for hoses.   Furthermore, (g) 1-100 weight part of softening agents for non-aromatic rubbers are contained, The thermoplastic elastomer composition for tubes or hoses of any one of Claims 1-6 characterized by the above-mentioned.   The tube and hose member which shape | molded the thermoplastic elastomer composition for tubes or hoses of any one of Claims 1-7.