JP2000072892A - Thermoplastic elastomer composition excellent in abrasion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyolefin elastomer composition excellent in abrasion resistance. SOLUTION: This composition is obtained by partly or perfectly crosslinking a mixture comprising (A) 1 to 99 pts.wt. of a copolymer of ethylene and a 6 to 12C α-olefin manufactured by using a metallocene catalyst, (B) 99 to 1 pts.wt. of a propylene resin [the sum of the (A) and (B) is 100 pts.wt.], (C) 5 to 100 pts.wt. of a thermoplastic urethane elastomer and (D) 0.5 to 30 pts.wt. of a copolymer of modified carboxylic acids.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefin-based thermoplastic elastomer composition having excellent abrasion resistance. More specifically, the present invention relates to an olefin thermoplastic elastomer composition having an excellent balance of physical properties such as abrasion resistance and mechanical strength, weather resistance, and processability.

[0002]

2. Description of the Related Art In recent years, olefin-based thermoplastic elastomer compositions have been widely used in various fields because of their high flexibility, excellent rubber-like properties, and ease of various molding processes.

[0003] Among them, a so-called dynamic crosslinking is carried out by melting and kneading a radically crosslinkable olefin elastomer and a thermoplastic resin having no radical crosslinkability such as polypropylene in a continuous or batch type kneader in the presence of radicals. The crosslinked composition is a known composition, and is used for applications such as automobile parts because the heat resistance, oil resistance, compression set and the like are remarkably improved by crosslinking the elastomer component. In recent years, due to increasing awareness of environmental issues, features such as fewer problems in waste disposal, recyclability, and lightness have been reviewed compared to conventionally used crosslinked rubber and soft polyvinyl chloride. Attention has been paid to olefin-based thermoplastic elastomer compositions, and there is an increasing movement to use these materials as substitutes.

However, olefin-based thermoplastic elastomer compositions generally have somewhat poor abrasion resistance and have been a major obstacle in substituting crosslinked rubber or soft polyvinyl chloride. As a conventional attempt, JP-A-7-26105 and JP-A-8-27325 disclose a styrene-isoprene block copolymer, a silicone oil, a fatty acid ester, and a fluoropolymer to improve the scratch resistance. A technique for performing this is disclosed. However,
There is a need for an olefin-based thermoplastic elastomer composition that does not always have a sufficient improvement effect and can withstand practical use.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an olefin-based thermoplastic elastomer composition having excellent abrasion resistance in view of the above situation.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that an olefin copolymer having a specific structure composed of ethylene and α-olefin and a thermoplastic polyurethane elastomer. It has been found that the problem can be solved by combining the compound with a carboxylic acid-modified copolymer, and the present invention has been completed.

That is, the present invention relates to (A) ethylene and carbon number 6
Ethylene-α-olefin copolymer 1 comprising α-olefins Nos. 1 to 12 and produced using a metallocene catalyst
To 99 parts by weight and (B) propylene resin 99 to 1 part by weight [total amount of (A) and (B) is 100 parts by weight] and (C)
A thermoplastic elastomer composition obtained by partially or completely crosslinking a mixture of 5 to 100 parts by weight of a thermoplastic polyurethane elastomer and 0.5 to 50 parts by weight of a (D) carboxylic acid-modified copolymer.

Hereinafter, the present invention will be described in detail.

Ethylene / α-olefin copolymer In the present invention, (A) the ethylene / α-olefin copolymer comprises ethylene and at least one or more carbon atoms having 6 or more carbon atoms.
~ 12 α-olefins.

As the α-olefin having 6 to 12 carbon atoms, for example, hexene-1,4-methylpentene-1,
Heptene-1, octene-1, nonene-1, decene-
1, undecene-1, dodecene-1 and the like. .
Among them, hexene-1, 4-methylpentene-1 and octene-1 are preferred, and octene-1 is particularly preferred. Octene-1 is excellent in softening effect even in a small amount, and the obtained copolymer is excellent in mechanical strength.

The ethylene / α-olefin copolymer used in the present invention can be produced with a known metallocene catalyst.

In general, a metallocene-based catalyst is composed of a cyclopentadienyl derivative of a Group IV metal such as titanium or zirconium and a cocatalyst, and is not only highly active as a polymerization catalyst but also a conventional catalyst such as a Ziegler-based catalyst. In comparison, the molecular weight distribution of the obtained polymer is narrow, and the distribution of the comonomer α-olefin having 6 to 12 carbon atoms in the copolymer is uniform. Therefore, the properties of the ethylene / α-olefin copolymer produced by the metallocene-based catalyst are greatly different from those of the conventional one using a Ziegler-based catalyst or the like.

The characteristics of an olefin copolymer composed of ethylene and an α-olefin using a metallocene polymerization catalyst are listed below. Since the polymerization catalyst has high activity, the composition of the comonomer α-olefin can be greatly increased as compared with the conventional one, and an elastomeric polymer having high flexibility can be obtained even without a plasticizer. The comonomer distribution is uniform compared to Ziegler-based polymers. Therefore, the reaction site can be uniform in the crosslinking reaction. 3. Extremely sharp molecular weight distribution, extremely low molecular weight components, excellent mechanical strength and processability, and high quality compared to Ziegler polymers. Despite the sharp molecular weight distribution, when a long-chain branch is introduced, the melt index (I10) at 190 ° C./10 kgf specified by ASTM D1238 and the melt index (I2) at 190 ° C./2.16 kgf are obtained. 4. The ratio (I10 / I2) is large, and the processing characteristics are excellent. 5. It does not contain a diene component and has excellent resistance to environmental degradation. Even if the copolymerization ratio of the α-olefin is high, blocking hardly occurs, and a pellet-like form is possible.

In the case of an olefin copolymer which is a copolymer of ethylene and an α-olefin with a Ziegler catalyst, the above-mentioned melt index ratio (I10 / I2) and the molecular weight distribution show a substantially linear proportional relationship. The molecular weight distribution tends to increase as the ratio increases. The molecular weight distribution is usually about 3 to 10.

On the other hand, in the case of an olefin polymer using a metallocene catalyst, the molecular weight distribution becomes a sharp value of less than 3.0, and the low molecular weight component is extremely small, regardless of the value of the melt index ratio. For this reason, workability is extremely excellent.

The molecular weight distribution (Mw / Mn) of these olefinic elastomers is calculated by GPC.

(A) used in the present invention is α-
The copolymerization ratio of the olefin is preferably 1 to 60% by weight, more preferably 10 to 50% by weight, and most preferably 20 to 45% by weight. When the copolymerization ratio of the α-olefin exceeds 60% by weight, the mechanical strength of the composition is lowered and it is difficult to use the composition practically. On the other hand, when it is less than 1% by weight, flexibility is insufficient.

The density of (A) is preferably in the range of 0.8 to 0.9 g / cm ³ from the balance between mechanical strength and flexibility.

The olefin copolymer used in the present invention preferably has a long chain branch. The presence of the long-chain branch enables the density to be lower than the ratio (% by weight) of the copolymerized α-olefin without lowering the mechanical strength. Hardness and high strength elastomer can be obtained. The ethylene / α-olefin copolymer having a long chain branch is described in US Pat. No. 5,278,272.

Further, (A) desirably has a DSC melting point peak at room temperature or higher. When it has a melting point peak, the form is stable in the temperature range below the melting point, the handleability is excellent, and the stickiness is small.

The melt index of (A) used in the present invention is 0.01 to 100 g / 10 min (19
(0 ° C., 2.16 kg load) is preferably used, and more preferably 0.2 to 10 g / 10 min.

When the amount exceeds 100 g / 10 minutes, the crosslinking property of the thermoplastic elastomer composition is insufficient, and
If it is less than 1 g / 10 minutes, the fluidity is poor and the processability is undesirably reduced.

(A) used in the present invention may be a mixture of a plurality of types. In such a case, it is possible to further improve the workability.

Propylene Resin In the present invention, the propylene resin (B) is a homo isotactic polypropylene, propylene and ethylene,
Other α- such as butene-1, pentene-1, hexene-1
Isotactic propylene resins with olefin (including block and random) and the like.

At least one resin selected from these resins is used in a composition ratio of 1 to 99 parts by weight. Preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight.
Parts by weight. If the amount is less than 1 part by weight, the fluidity and processability of the composition are reduced, and if it exceeds 99 parts by weight, the flexibility of the composition is insufficient, which is not desirable.

The melt index of the propylene resin (B) in the present invention is from 0.1 to 100 g / 10
Min (230 ° C., 2.16 kg load) is preferably used. If it exceeds 100 g / 10 minutes, the heat resistance of the composition, mechanical strength such as adhesive strength tends to decrease,
On the other hand, if it is less than 0.1 g / 10 minutes, the fluidity is poor and the molding processability is undesirably reduced.

In the present invention, a softening agent may be added to the composition comprising (A) and (B), if necessary, to improve workability.

The above-mentioned softening agent is preferably a paraffinic or naphthenic process oil. These are used in an amount of 0 to 250 parts by weight, preferably 10 to 150 parts by weight, per 100 parts by weight of (A) and (B) for adjusting the hardness and flexibility of the composition. If the amount exceeds 250 parts by weight, oil bleed becomes remarkable, which is not desirable.

In the present invention, the thermoplastic elastomer composition comprising (A) and (B) is used in combination with (A) the specific ethylene / α-olefin copolymer and (B) propylene resin described above. If necessary, by combining a softener with a specific composition ratio, the balance between mechanical strength, flexibility and workability is improved, and the composition can be preferably used.

Thermoplastic Polyurethane Elastomer The thermoplastic polyurethane elastomer of the present invention is one obtained by addition-polymerizing a long-chain glycol and a short-chain glycol having active hydrogen at both terminals using a diisocyanate compound. There are no particular restrictions on the compound used, but typical long-chain glycols include polyesters, polyethers, and polycarbonates. Specific examples of the compound include a polyester-based dehydration condensate of adipic acid and various glycols such as poly (ethylene adipate), poly (diethylene adipate), poly (1,4-butylene adipate), and poly (1,1). 6-hexane adipate), and polycaprolactone can also be used. Polyethers include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (propylene glycol / ethylene glycol), and polycarbonates include poly (1,6-hexamethylene glycol carbonate).

Polyolefin glycols are also useful, and polybutadiene diol, polyisoprene diol and hydrogenated products thereof can be preferably used.

As the short-chain glycols, aliphatic glycols, aromatic glycols and the like are typical. As the specific compound names, ethylene glycol, 1,3-propylene glycol,
Examples include 1,4-butane glycol, 1,3-butane glycol, 1,5-pentane glycol, 1,6-hexane glycol, and the like. Examples of aromatic glycols include bisphenol A, hydroquinone diethylol ether, bisphenol A / Examples include ethylene glycol.

The diisocyanate includes aromatic, alicyclic, and aliphatic diisocyanates, such as tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalenedi isocyanate, hexamethylene diisocyanate, and the like. Examples thereof include isophorone diisocyanate and the like, and further include hydrogenated products of xylylene diisocyanate and 4,4′-diphenylmethane diisocyanate.

The thermoplastic polyurethane elastomer generally has excellent abrasion resistance, and is useful for improving the abrasion resistance of the entire composition of the present invention by being added as a component of the composition. Thermoplastic polyurethane elastomers have a relatively high specific gravity and slightly inferior rebound resilience and snappy properties, but olefin elastomers have excellent properties, but olefin elastomers and thermoplastic polyurethane elastomers complement each other's disadvantages. hand,
Overall, they form a well-balanced thermoplastic elastomer composition. Olefin elastomers are generally inferior in oil resistance, but polyurethane elastomers are excellent, and are useful in improving the oil resistance of olefin elastomers.

The amount of the thermoplastic polyurethane elastomer component used in the present invention is 5 to 100 parts by weight based on 100 parts by weight of the total of (A) and (B). If the amount is less than 5 parts by weight, the improvement in wear resistance is unsatisfactory.
Even when used in a large amount exceeding 00 parts by weight, the improvement in wear resistance reaches a peak, and conversely, physical properties such as rebound resilience and compression set are reduced, and further, water absorption is deteriorated and cost is increased, which is desirable. No composition can be obtained. A more desirable amount is in the range of 10 to 50 parts by weight.

Carboxylic acid-modified copolymer The carboxylic acid-modified copolymer is composed of an ethylene / α-olefin copolymer having no polar group and a propylene resin,
It enhances compatibility with polar thermoplastic polyurethane elastomers, and acts as a compatibilizer for functioning as a finely dispersed integral composition.

The carboxylic acid-modified copolymer of the present invention can be roughly classified into two. First, an olefin-based polymer contains at least one compound selected from the group consisting of ethylenically unsaturated group-containing carboxylic acids and derivatives thereof in an amount of 0.05 to 100 parts by weight per 100 parts by weight of the base polymer.
It is a modified copolymer obtained by binding 30 parts by weight.

The method of bonding includes graft polymerization and copolymerization.

Second, at least one compound selected from the group consisting of ethylenically unsaturated group-containing carboxylic acids and derivatives thereof is added to the hydrogenated block copolymer in an amount of 0.05 to 100 parts by weight of the base polymer. It is a modified copolymer formed by bonding to 30 parts by weight. Examples of the method of bonding include graft polymerization and copolymerization.

First, at least one compound selected from the group consisting of ethylenically unsaturated group-containing carboxylic acids and derivatives thereof is added to the olefin-based polymer in an amount of 0.05 to 100 parts by weight of the base copolymer. The modified copolymer formed by bonding to 30 parts by weight will be described below.

Here, the olefin polymer is a homopolymer or a copolymer mainly composed of an olefin having 2 to 12 carbon atoms. For example, polyethylene, polypropylene, polybutene, a copolymer of ethylene and at least one or more α-olefins having 3 to 12 carbon atoms, propylene and at least one or more of α-olefins having 4 to 12 carbon atoms And copolymers.

The first carboxylic acid-modified copolymer is obtained by bonding at least one compound selected from the group consisting of a carboxylic acid containing an ethylenically unsaturated group or a derivative thereof to the above-mentioned base polymer.

Examples of such an ethylenically unsaturated group-containing carboxylic acid or a derivative thereof include maleic acid, halogenated maleic acid, fumaric acid, itaconic acid, and cis-4-acid.
Cyclohexene-1,2-dicarboxylic acid, endo-cis-bicyclo (2,2,1) -5-heptene-2,3-dicarboxylic acid and the like, and anhydrides, esters, amides and imides of these dicarboxylic acids, vinyl acetate And the like, and further acrylic acid, methacrylic acid, crotonic acid and the like and esters of these monocarboxylic acids, for example, methyl acrylate,
Examples include derivatives such as ethyl acrylate, methyl methacrylate, ethyl methacrylate, glycidyl acrylate, glycidyl methacrylate and amide. Further, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate,
2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, 3-hydroxy-2-phenoxypropyl acrylate, 3- Hydroxy-2-phenoxypropyl methacrylate and the like are also exemplified. Among them, maleic anhydride, glycidyl methacrylate and 2-hydroxyethyl methacrylate are particularly preferably used. These compounds can be used alone or further
A combination of more than one species can also be used. When modifying the basic olefin polymer, in addition to the compounds described above, vinyl aromatic compounds such as styrene and α-methylstyrene may be used as long as the properties of the modified olefin polymer of the present invention are not impaired. A group compound can be used in combination.

The modified olefin polymer of the present invention may be prepared, for example, by adding at least one compound selected from the group consisting of an ethylenically unsaturated group-containing carboxylic acid or a derivative thereof to a base olefin polymer in a solution state or a molten state. In the above, the addition is performed with or without the use of a radical initiator.

As the radical initiator used in the above addition, an organic peroxide, an azo compound or the like is usually suitably used.

Specific examples of the organic peroxide include 1,1-
Bis (t-butylperoxy) -3,5,5-trimethylcyclohexane, di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane And 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3. Further, as a specific example of the azo compound,
Azoisobutyronitrile and the like can be mentioned. Such radical initiators can be used alone or in combination of two or more.

The method for producing these modified olefin polymers is not particularly limited in the present invention, but the resulting modified olefin polymers may contain undesirable components such as insoluble and infusible gels, A method in which the melt viscosity is significantly increased and the processability is deteriorated is not preferable.
As a method preferably used, for example, there is a method of reacting a base olefin polymer with a carboxylic acid containing an ethylenically unsaturated group or a derivative thereof in the presence of a radical initiator in an extruder.

The amount of the ethylenically unsaturated group-containing carboxylic acid or its derivative compound to be added is 0.05 to 30 parts by weight, preferably 0.5 to 20 parts by weight, per 100 parts by weight of the base olefin polymer. Department. If the added amount is less than 0.05 part by weight, it is not preferable because the improvement in compatibility between other components in the case of the composition is very small. Also,
If the added amount exceeds 30 parts by weight, the effect of improving the compatibility is hardly increased as compared with the amount less than 30 parts by weight, and instead the gel content is increased, which is not preferable.

Next, at least one compound selected from the group consisting of ethylenically unsaturated group-containing carboxylic acids and derivatives thereof is added to the second hydrogenated block copolymer per 100 parts by weight of the base copolymer. 0.05-30
The modified copolymer obtained by bonding parts by weight will be described below.

Here, the hydrogenated block copolymer means a block copolymer obtained by hydrogenating a block copolymer comprising a vinyl aromatic compound and a conjugated diene compound.

The hydrogenated block copolymer of the present invention comprises a block consisting of at least one polymer block A mainly composed of a vinyl aromatic compound and at least one polymer block B mainly composed of a conjugated diene compound. It is a block copolymer obtained by hydrogenating a copolymer.

For example, AB, ABA, BAB
-A, ABABA, BABAB, (A
_{-B) 4 Si, (B-} A-B) 4 Si, (B-A-B) 4
It has a structure such as Sn.

The polymer block mainly composed of a vinyl aromatic compound refers to a copolymer block of a vinyl aromatic compound containing 50% by weight or more of a vinyl aromatic compound and a conjugated diene compound and / or a single polymer of a vinyl aromatic compound. Shows the coalescing block.

The polymer block mainly composed of a conjugated diene compound refers to a copolymer block of a conjugated diene compound containing at least 50% by weight of a conjugated diene compound and a vinyl aromatic compound and / or a homopolymer block of a conjugated diene compound. Show.

As the vinyl aromatic compound constituting the block copolymer, styrene, methylstyrene, 1,3-
One or more of dimethylstyrene, p-tert-butylstyrene and the like can be used. Among them, styrene is preferred.

As the conjugated diene compound constituting the block copolymer, one or more of butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like can be used. . Among them, butadiene, isoprene and a combination thereof are preferred.

The block copolymer may be produced by any known method, for example, using a polymerization initiator such as an organic lithium compound in a hydrocarbon solvent to block a vinyl aromatic compound and a conjugated diene compound. It is a method of polymerizing.

The block copolymer obtained by hydrogenation can be obtained by subjecting the block copolymer to a hydrogenation reaction. The method of the hydrogenation reaction may be any known method, for example, hydrogenation can be performed in an inert solvent in the presence of a hydrogenation catalyst. The reaction conditions for hydrogenation are selected such that at least 80%, preferably 90% or more, of the conjugated diene compound is hydrogenated, while less than 20%, preferably less than 10%, of the vinyl aromatic compound is hydrogenated. Is done.

The number average molecular weight of the block copolymer having the above structure is 20,000 to 300,000, preferably 30.
000 to 200,000.

The second carboxylic acid-modified copolymer is obtained by bonding at least one compound selected from the group consisting of a carboxylic acid containing an ethylenically unsaturated group or a derivative thereof to the above-mentioned base polymer.

Examples of such a carboxylic acid containing an ethylenically unsaturated group or a derivative thereof include those equivalent to those of the first carboxylic acid-modified copolymer.

The specific examples of the bonding method and the production method are the same as those of the first carboxylic acid-modified copolymer.

The addition amount of the ethylenically unsaturated group-containing carboxylic acid or its derivative compound is 0.05 to 30 parts by weight, preferably 0.5 to 20 parts by weight, per 100 parts by weight of the base block copolymer. Department. If the added amount is less than 0.05 part by weight, it is not preferable because the improvement in compatibility between other components in the case of the composition is very small. Also,
If the added amount exceeds 30 parts by weight, the effect of improving the compatibility is hardly increased as compared with the amount less than 30 parts by weight, and instead the gel content is increased, which is not preferable.

The present invention provides (A), (B),
It is necessary that the thermoplastic elastomer composition composed of (C) and (D) be partially or completely crosslinked with a radical initiator such as an organic peroxide or a radical initiator and a crosslinking assistant. . This makes it possible to further improve the mechanical strength, heat resistance, oil resistance and the like of the composition.

Here, specific examples of the radical initiator preferably used include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane,
1,1-bis (t-hexylperoxy) -3,3,5
-Trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-
Butylperoxy) cyclododecane, 1,1-bis (t
-Butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-4,
Peroxy ketals such as 4-bis (t-butylperoxy) butane and n-butyl-4,4-bis (t-butylperoxy) valerate; di-t-butyl peroxide, dicumyl peroxide, t -Butylcumyl peroxide, α, α′-bis (t-butylperoxy-m
-Isopropyl) benzene, α, α'-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane and 2,5-dimethyl-2,5 Dialkyl peroxides such as -bis (t-butylperoxy) hexyne-3; acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexa Diacyl peroxides such as noyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide and m-trioyl peroxide; t-butylperoxyacetate, t
-Butylperoxyisobutyrate, t-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate,
Di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, and cumylperoxyoctate Peroxyesters; and
Hydrogens such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide and 1,1,3,3-tetramethylbutyl peroxide Peroxides can be mentioned.

Among these compounds, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl -2,5-bis (t-butylperoxy) hexane and 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3 are preferred.

These radical initiators include (A) 100
0.02 to 3 parts by weight, preferably 0.05 to 3 parts by weight
Used in an amount of １1 part by weight. If the amount is less than 0.02 parts by weight, the crosslinking is insufficient, and if it exceeds 3 parts by weight, the physical properties of the composition are not improved, which is not preferable. Further, as a crosslinking aid,
Divinylbenzene, triallyl isocyanurate, triallyl cyanurate, diacetone diacrylamide,
Polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diisopropenylbenzene,
P-quinone dioxime, P, P'-dibenzoylquinone dioxime, phenylmaleimide, allyl methacrylate, N, N'-m-phenylenebismaleimide, diallyl phthalate, tetraallyloxyethane, 1,2-polybutadiene and the like are preferable. Used. These crosslinking aids may be used in combination of two or more.

These crosslinking aids are used in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight, per 100 parts by weight of (A). If the amount is less than 0.1 part by weight, crosslinking is insufficient, and if it exceeds 5 parts by weight, the physical properties of the composition are not improved, and an excessive amount of a crosslinking aid remains, which is not preferable.

Further, if necessary, other resins and elastomers may be added to the thermoplastic elastomer composition of the present invention to such an extent that its characteristics are not impaired. Examples are polyethylene, polybutene, polyisobutene, ethylene-vinyl ester copolymers such as ethylene-vinyl acetate copolymer, ethylene-unsaturated carboxylic acid ester copolymers such as ethylene-ethyl acrylate copolymer, ethylene-vinyl alcohol There are copolymers, block copolymers composed of vinyl aromatic and conjugated dienes, and hydrogenated products of block copolymers composed of vinyl aromatic and conjugated diene.

Further, the thermoplastic elastomer composition of the present invention can contain an inorganic filler and a plasticizer to such an extent that the characteristics thereof are not impaired. Examples of the inorganic filler used here include calcium carbonate, magnesium carbonate, silica, carbon black, glass fiber, titanium oxide, clay, mica, talc, and magnesium hydroxide. Also, as the plasticizer, for example,
Polyethylene glycol, dioctyl phthalate (DO
And phthalic acid esters such as P). Further, other additives, for example, organic / inorganic pigments, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, silicone oils, and the like are also suitably used.

For the production of the thermoplastic elastomer composition of the present invention, general resins such as a Banbury mixer, a kneader, a single-screw extruder and a twin-screw extruder used for the production of an elastomer composition can be used. It is possible to adopt a method.

However, among them, a twin-screw extruder is preferably used. The twin-screw extruder is more suitable for uniformly and finely dispersing the components and further adding other components to cause a cross-linking reaction to continuously produce the thermoplastic elastomer composition of the present invention. ing.

The form of each component such as an ethylene / α-olefin copolymer and a propylene-based polymer used in the present invention is preferably a finely divided form such as pellets, powders and crumbs.

The thermoplastic elastomer composition of the present invention comprises:
As a specific example, it can be manufactured through the following processing steps.

That is, an ethylene / α-olefin copolymer, a propylene-based polymer, a thermoplastic polyurethane elastomer, and a carboxylic acid-modified copolymer are mixed well, and the mixture is charged into a hopper of an extruder. The radical initiator and the crosslinking assistant may be added together with the ethylene / α-olefin copolymer and the propylene-based polymer from the beginning, or may be added in the middle of the extruder. The rubber oil may be added from the beginning of the extruder, or may be added halfway,
You may add separately in the beginning and in the middle. Ethylene α-
The olefin copolymer and the propylene-based polymer may be partially added in the middle of the extruder. The thermoplastic polyurethane elastomer and the carboxylic acid-modified copolymer may be added in the middle of the extruder where the cross-linking reaction is almost completed. When heated and melted and kneaded in an extruder, the ethylene / α-olefin copolymer, a radical initiator and a crosslinking assistant undergo a crosslinking reaction, and a crosslinking reaction is performed by adding a rubber oil or the like and melt-kneading. After sufficient mixing and kneading and dispersion, the mixture is taken out of the extruder. Pellets can be obtained to obtain pellets of the thermoplastic elastomer composition of the present invention.

The thermoplastic elastomer composition thus obtained can be used to produce various molded articles by any molding method. Injection molding, extrusion molding, compression molding, blow molding, calender molding, foam molding and the like are preferably used.

[0077]

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In these examples and comparative examples, the test methods used for evaluating various physical properties are as follows.

(1) Surface Hardness Four sheets having a thickness of 2 mm were stacked and evaluated according to ASTM D2240 using a type A in an atmosphere of 23 ° C.

(2) Tensile breaking strength [kgf / cm ² ] Evaluated at 23 ° C. according to JIS K6251.

(3) Tensile Elongation at Break [%] Evaluated at 23 ° C. according to JIS K6251.

(4) Weather Resistance Using a carbon arc type sunshine weather meter (manufactured by Suga Test Instruments), a black panel temperature of 63 ° C., a rainfall time of 18 minutes and an irradiation time of 120 were applied according to ASTM D1499.
And the tensile breaking elongation retention [%] after continuously exposing the 2 mm thick compression molded sheet for 500 hours.

(5) Taber abrasion test This is performed according to JIS K7311. Wear wheel; H-18,
Load: 1 kgf, rotation speed: 60 rpm, abrasion amount (mg) after 1000 rotation wear was measured.

The following components were used in Examples and Comparative Examples.

(A) Ethylene / α-olefin copolymer Copolymer of ethylene and octene-1 (referred to as EOR) Composition of ethylene / octene-1 of a copolymer produced by a method using a metallocene catalyst Ratio: 75/25 (weight ratio), density: 0.87 g / cm ³ , MFR: 0.5 (1
90 ° C. × 2.16 kg), Mw / Mn = 2.3, long chain branching, DSC melting point peak, ethylene-propylene-ethylidene norbornene copolymer (referred to as EPDM) manufactured by a method using a Ziegler catalyst did. Propylene content: 28% by weight, iodine value 15, density: 0.8
7 g / cm ³ , MFR; 0.4 (190 ° C. × 2.16 k
g), having no long-chain branching, and having no DSC melting point peak (ii) Propylene resin Polypropylene (referred to as PP) Homo isotactic polypropylene, MFR15
(230 ° C. × 2.16 kg) (c) Thermoplastic polyurethane elastomer (c-1) Polyester-based polyurethane elastomer (referred to as TPU-1) Elastran C80A (manufactured by Takeda Birdish Urethane Industry Co., Ltd.), hardness 81 (c -2) Polyether-based polyurethane elastomer (referred to as TPU-2) Elastran ET880 (manufactured by Takeda Birdish Urethane Industry Co., Ltd.), hardness 80 (d) Carboxylic acid-modified copolymer (d-1) Carboxylic acid-modified copolymer Polymer (referred to as CPE) Copolymer of ethylene and ethyl acrylate EEA DPDJ-6169 (Nihon Unicar Co., Ltd.)
(D-2) carboxylic acid-modified styrene / butadiene block copolymer (referred to as CHTR) having a structure of BABA and a number average molecular weight of 5100
0, maleic anhydride is added to 100 parts by weight of a hydrogenated styrene / butadiene block copolymer having a styrene content of 30% by weight and a hydrogenation ratio of polybutadiene of 99%.
Parts by weight and 0.1 parts by weight of 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane were added to cause an addition reaction in an extruder.

(E) Softener Paraffin oil (referred to as MO) Diana Process Oil PW-90 (Idemitsu Kosan Co., Ltd.)
(F) Radical generator (referred to as POX) 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3 (v) crosslinking aid divinylbenzene (referred to as DVB) To 6, Comparative Examples 1 to 3 As an extruder, a twin-screw extruder (L / D = 47) having an inlet at the center of the barrel was used. A double screw having a kneading part by a kneading disk before and after the injection port was used as the screw.

A predetermined amount of an ethylene / α-olefin copolymer and a propylene-based resin were first melt-kneaded in a twin-screw extruder (cylinder temperature 220 ° C.) to form pellets. Next, POX and DVB adhered to the pellets were again charged from the hopper of the extruder (cylinder temperature 220 ° C.). Add MO from the injection port at the center of the barrel,
Melt kneading and a crosslinking reaction were performed to pelletize. Thereafter, a predetermined amount of a preliminarily dried thermoplastic polyurethane elastomer and a carboxylic acid-modified copolymer were further added, and the mixture was melt-kneaded by a twin-screw extruder (cylinder temperature: 220 ° C.) to produce pellets.

A sheet having a thickness of 2 mm was prepared from the elastomer composition thus obtained by compression molding at 200 ° C., and various physical properties were evaluated.

Table 1 shows the results.

[0089]

[Table 1]

All of the examples were superior to the comparative examples in abrasion resistance, mechanical strength and weather resistance, and were excellent in physical property balance.

[0091]

Industrial Applicability The thermoplastic elastomer composition of the present invention has an excellent balance between physical properties such as abrasion resistance and mechanical strength, weather resistance, workability, and the like, and its utility value is extremely large. In particular,
It can be effectively used for various applications as a substitute for crosslinked rubber or soft polyvinyl chloride.

The thermoplastic elastomer composition of the present invention can be used for interior and exterior parts of automobiles such as airbag covers, instrument panels, lamp end rubbers, console boxes, shift knob grips, home appliances, light electric appliance housings, various grips, and the like. It can be widely used for various switches, various key tops, electric wire covering materials, hoses, belts, toys, miscellaneous goods, daily necessities, building materials, sheets, films and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08L 51/06 C08L 51/06 75/04 75/04 F term (Reference) 4F070 AA13 AA15 AA53 AB03 AC56 AC57 AE08 GA05 GA06 4F071 AA15 AA20 AA21X AA33X AA36X AA53 AA78 AE02A AE06A AG05 AH03 AH11 AH12 DA22 4J002 BB004 BB05W BB064 BB074 BB094 BB104 BB11X BB12X BB14X BB204 CK02Y EA047 ED027 EH077 EH147 EK016 EK036 EK046 EK056 EK066 ES017 ET007 EU027 EU197 FD157 FD206 GC00 GL00 GN00 GQ00

Claims (2)

[Claims] (A) ethylene and α- having 6 to 12 carbon atoms
1 to 99 parts by weight of an ethylene / α-olefin copolymer produced using a metallocene catalyst composed of an olefin and 99 to 1 part by weight of (B) a propylene resin [the total amount of (A) and (B) is 100 Parts by weight], a mixture comprising (C) 5 to 100 parts by weight of a thermoplastic polyurethane elastomer and (D) 0.5 to 50 parts by weight of a carboxylic acid-modified copolymer, partially or completely crosslinked. Elastomer composition. 2. The carboxylic acid-modified copolymer is obtained by adding at least one compound selected from the group consisting of an ethylenically unsaturated group-containing carboxylic acid or a derivative thereof to an olefin polymer by 100 parts by weight of the base polymer. 0.05 ~
At least one compound selected from the group consisting of ethylenically unsaturated group-containing carboxylic acids and derivatives thereof is added to the modified copolymer or the hydrogenated block copolymer having 30 parts by weight of the base polymer 100 2. The thermoplastic elastomer composition according to claim 1, which is a modified copolymer obtained by bonding 0.05 to 30 parts by weight per part by weight.