JP2000034372A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition that retains the flexibility and elastic recovery intrinsically unique to ethylene-α-olefin copolymer, shows excellent melt-moldability with no occurrence of necking, cracking or agglutination and has excellent appearance, blocking resistance, strength and low residual strain, and moldings therefrom. SOLUTION: This thermoplastic elastomer composition comprises (a) an ethylene-α-olefin copolymer and (b) a thermoplastic polyurethane that satisfies the following requirements: (1) this thermoplastic polyurethane is prepared by reaction of a polyester diol having a number-average molecular weight of 1,500-5,000 with an organic isocyanate and a chain extender; (2) the content of nitrogen atoms is >=2.6 wt.%; (3) the endothermic peaks are in the temperature range from 200-220 deg.C; (4) the crystallization enthalpy (ΔH) is 2-15 J/g in the temperature range of 200-220 deg.C according to DSC; at a weight ratio a/b of 70/30-90/10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoplastic elastomer composition mainly comprising an ethylene-α-olefin copolymer and a specific thermoplastic polyurethane, and a molded article comprising the same. The thermoplastic elastomer composition of the present invention is excellent in melt moldability, for example, when producing a film or sheet using a T-die extruder,
The product can be obtained with a high yield by preventing the occurrence of necking phenomena and cracks that narrow the width of the film or sheet.Moreover, since it is difficult to adhere and has excellent blocking resistance, a large amount of lubricant and release paper must be used. Even if not used, blocking of the molded article can be prevented, and, for example, film and sheet can be smoothly wound and unwound.
Moreover, in the thermoplastic elastomer composition of the present invention, since the ethylene-α-olefin copolymer and the specific thermoplastic polyurethane are uniformly dispersed, a molded article such as a film or a sheet obtained therefrom has irregularities. It has a smooth and excellent appearance without any swelling (fish eyes), moderate strength, excellent elastic recovery, small residual strain after elongation, and can be effectively used as a stretchable material.

[0002]

2. Description of the Related Art Despite having elasticity, a thermoplastic elastomer composition does not require a vulcanization treatment as in natural rubber or diene rubber, and has the same properties as a thermoplastic resin in melt molding and molding. Since it is heat-processable and has excellent moldability, it has recently been used in a wide range of fields such as automobile parts, parts for home appliances, toys, sporting goods, and daily necessities. . Various types of thermoplastic elastomer compositions have been conventionally proposed. Among them, for example, thermoplastic resins such as thermoplastic polyurethane, polyvinyl chloride, styrenic polymer, and polyolefin have ethylene-α- A thermoplastic polyolefin-based elastomer composition containing an olefin copolymer is known. For example, Tokuhyohei 8-50
No. 1343 discloses a specific melt flow ratio for thermoplastic materials such as thermoplastic polyurethane, polyvinyl chloride, styrene-based polymer and polyolefin for the purpose of improving impact resistance and transparency at low temperatures. Molecular weight distribution (Mw /
Mn) and a thermoplastic olefin-based polymer composition blended with an ethylene-α-olefin copolymer having a critical shear temperature.

[0003] However, in the above-mentioned conventional thermoplastic polyolefin-based elastomer compositions, including those described in JP-A-8-501343, the flexibility inherent in the ethylene-α-olefin copolymer is inherent. Such properties are often impaired. In addition, when a film or sheet is manufactured using a conventional thermoplastic polyolefin-based elastomer composition using a T-die extruder, a necking phenomenon in which the width of the film or sheet becomes narrow, cracking of the film or sheet, For example, a film or sheet product obtained by trimming both ends having uneven thickness has a problem that the width is extremely narrow, a defective product with cracks is generated, and the yield of the product is reduced. In addition, the molded product obtained therefrom has a strong adhesive property, and in order to prevent sticking (blocking), it is necessary to add a large amount of a lubricant or take up a film or sheet using expensive release paper together. There are problems such as the problem of seepage of the lubricant onto the surface of the molded article due to the use of the lubricant, and the complicated labor and cost increase associated with the use of the release paper.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ethylene-α-olefin copolymer having excellent inherent properties, particularly flexibility and elastic recovery, and excellent melt moldability. It is possible to produce molded products such as films and sheets excellent in appearance and physical properties with high yield and high productivity without causing necking phenomenon or cracking.
An object of the present invention is to provide a thermoplastic elastomer composition based on an ethylene-α-olefin copolymer. The object of the present invention, in addition to the properties described above, is that there is no sticking and excellent blocking resistance, even if a large amount of a lubricant is not blended, or even if a release paper is not used in combination, a film or a sheet is used. It is an object of the present invention to provide a thermoplastic elastomer composition based on an ethylene-α-olefin copolymer, which can smoothly take up and unwind a molded article of the above. Furthermore, an object of the present invention is to produce a molded article such as a film or a sheet having excellent strength as described above, appropriate strength, and excellent elastic recovery, and having small residual strain after elongation. Ethylene-α
-To provide a thermoplastic elastomer composition based on an olefin copolymer. And the present invention
An object of the present invention is to provide a molded article comprising the above-mentioned thermoplastic elastomer composition.

[0005]

As a result of repeated studies by the present inventor in order to achieve the above-mentioned object, the above-mentioned Japanese Patent Application Laid-Open No. Hei 8-50 is disclosed.
In a conventional thermoplastic polyolefin-based elastomer composition described in, for example, No. 1343, as a thermoplastic resin used in combination with an ethylene-α-olefin copolymer, a thermoplastic polyurethane or polypropylene having a low crystal melting temperature, etc. The thermoplastic resin is used, and due to this, the above-mentioned necking phenomenon and cracking problem in the production of films and sheets, the problem of blocking (sticking) in molded products, and the like easily occur, and It was found that the recovery stress after elongation of the obtained molded article was small and the residual strain after elongation was large.

Accordingly, the present inventors have further studied based on the above findings found by the present inventors. As a result, for the ethylene-α-olefin copolymer, polyester-based thermoplastic polyurethane having specific physical properties,
That is, when a polyester-based thermoplastic polyurethane having a specific nitrogen atom content, a crystal melting temperature, and a crystallization enthalpy (ΔH) is blended in a specific ratio, a thermoplastic elastomer composition obtained by the T-die extrusion molding is obtained. When a film or sheet is manufactured using a machine or the like, the necking phenomenon in which the width of the film or sheet becomes narrow, the cracking of the film or sheet is prevented, and the appearance is free from irregularities and bumps (fish eyes) In addition, the thermoplastic elastomer composition and the molded article comprising the same have no blocking and have excellent blocking resistance, and can be smoothly wound and unwound without using a large amount of a lubricant or release paper. In addition, a molded article obtained from the thermoplastic elastomer composition has an appropriate strength and an elasticity. It found that residual strain after elongation have excellent recovery properties is small, and completed the present invention based on their various findings.

That is, the present invention relates to (i) ethylene-
The α-olefin copolymer (a) and the thermoplastic polyurethane (b) were converted from the ethylene-α-olefin copolymer (a): thermoplastic polyurethane (b) = 70:30 to 9
A thermoplastic elastomer composition containing the thermoplastic polyurethane (b) in a weight ratio of 0:10; and (ii) a polyester having a number average molecular weight of 1,500 to 5,000. A thermoplastic polyurethane obtained by a reaction of a diol, an organic diisocyanate and a chain extender; a nitrogen atom content of 2.6% by weight or more; an endothermic peak by differential scanning calorimetry (DSC) of 20
In the temperature range of 0-220 ° C; and 200-220 ° C by differential scanning calorimetry (DSC)
Is a thermoplastic polyurethane that satisfies the enthalpy of crystallization (ΔH) determined from the endothermic peak area in the temperature range of 2 to 15 J / g;

[0008] The present invention is a molded article comprising the above-mentioned thermoplastic elastomer composition.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the thermoplastic elastomer composition of the present invention, any of a copolymer of ethylene and an α-olefin can be used as the ethylene-α-olefin copolymer (a),
Although not particularly limited, among them, a copolymer of ethylene and an α-olefin having 4 or more carbon atoms and a unit (I) derived from ethylene in the copolymer: an α-olefin having 4 or more carbon atoms The ethylene-α-olefin copolymer in which the molar ratio of the unit (II) derived from is 55:45 to 99: 1 is preferably used. In the ethylene-α-olefin copolymer (a), the molar ratio of the unit (I): unit (II) is more preferably 75:25 to 95: 5, and 85:15 to 95: 5. Is more preferable. Such an ethylene-α-olefin copolymer has a high softening temperature and a thermoplastic polyurethane (b)
Excellent uniform mixing with Moreover, when the thermoplastic elastomer composition of the present invention containing such an ethylene-α-olefin copolymer is extrusion-molded to produce a molded product such as a film or sheet, there is no occurrence of necking phenomenon or cracking. In addition, a molded article having excellent blocking resistance, elastic recovery, and elasticity can be obtained.

[0010] Ethylene-α-olefin copolymer (a)
If the proportion of units derived from ethylene in the above is less than 55 mol%, the softening point of the ethylene-α-olefin copolymer will be low, and it will be difficult to achieve uniform mixing with the thermoplastic polyurethane (b). When a film or sheet is produced from the plastic elastomer composition, necking, cracking, poor appearance, and the like are likely to occur, and blocking (sticking) is likely to occur in the obtained molded product.
On the other hand, when the proportion of units derived from ethylene in the ethylene-α-olefin copolymer (a) exceeds 99 mol%, it is difficult to obtain a film having a small thickness and excellent stretchability.

The copolymer of ethylene and an α-olefin having 4 or more carbon atoms, which is preferably used as the ethylene-α-olefin copolymer (a) in the thermoplastic elastomer composition of the present invention, has 4 or more carbon atoms. As units (II) derived from α-olefins, for example, 1-butene, 2-methyl-1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene , 1-octene, 1-decene, 1-octadecene, and other units derived from α-olefins. These α-olefin units (II) may be contained singly or in combination of two or more. You may make it contain. Among them, the unit (II) is preferably a unit derived from an α-olefin having 4 to 12 carbon atoms, and has 7 to 7 carbon atoms.
The unit is more preferably a unit derived from 10 α-olefins, and even more preferably a unit derived from 1-octene. When the ethylene-α-olefin copolymer (a) is a copolymer of ethylene and an olefin having 3 or less carbon atoms (propylene), such ethylene-α-olefin copolymer (a)
α-olefin copolymer as thermoplastic polyurethane (b)
And the molded article obtained therefrom tend to have low flexibility and elastic recovery after elongation.

The ethylene-α-olefin copolymer (a) may have a small amount of a unit derived from a non-conjugated diene compound, if necessary, together with the α-olefin unit described above. In this case, examples of the non-conjugated diene compound include ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, and methylene norbornene.

[0013] Ethylene-α-olefin copolymer (a)
The melt index measured at 190 ° C. under a load of 2.16 kg is preferably in the range of 0.1 to 12 g / 10 min, more preferably in the range of 0.2 to 7 g / 10 min. , 0.4 to 5 g / 10 min. When the melt index of the ethylene-α-olefin copolymer (a) is less than 0.1 g / 10 minutes, the thermoplastic elastomer composition tends to be hard and poor in flexibility, and has a small thickness. Is easily difficult to manufacture. On the other hand, the ethylene-α-olefin copolymer (a) has a melt index of 12 g /
If the time exceeds 10 minutes, the thermoplastic elastomer composition and the molded article obtained therefrom are liable to cause blocking, and the mechanical properties are liable to deteriorate. The melt index of the ethylene-α-olefin copolymer referred to in this specification is a value measured according to ASTM D-1238.

Ethylene-α-olefin copolymer (a)
Preferably has a Shore A hardness in the range of 30 to 90, and more preferably in the range of 40 to 85. When the Shore A hardness of the ethylene-α-olefin copolymer (a) is less than 30, the mechanical properties of a molded article obtained from a thermoplastic elastomer composition containing the same tend to decrease. On the other hand, if the Shore A hardness of the ethylene-α-olefin copolymer (a) exceeds 90, the flexibility of the thermoplastic elastomer composition containing the copolymer and the molded article obtained therefrom tends to be insufficient. The Shore A hardness referred to in this specification is ASTM.
It is a value measured according to D-2240.

Ethylene-α-olefin copolymer (a)
Is preferably that the density is in the range of ^{0.85~0.93g / cm 3, 0.86~0.91g / cm} 3
More preferably in the range of 0.86 to 0.9
More preferably, it is within the range of 0 g / cm ³ . By using the ethylene-α-olefin copolymer (a) having the above density, the melt moldability, blocking resistance, flexibility, and elastic recovery (low residual strain) of the thermoplastic elastomer composition of the present invention are improved. It will be even better. In addition, the density referred to in the present specification is a value measured in accordance with ASTM D-792.

Ethylene-α-olefin copolymer (a)
Is preferably a Mooney viscosity measured at 100 ° C. using an L-shaped rotor is in the range of _{5~70ML 1 + 4 (100 ℃)} , within the scope of 10~55ML ₁ + 4 (100 ℃) More preferably, there is. By using the ethylene-α-olefin copolymer (a) having the Mooney viscosity described above, the thermoplastic elastomer composition of the present invention has melt moldability, blocking resistance, flexibility, and elastic recovery (low residual distortion). ) Will be better. The Mooney viscosity referred to in the present specification is a value measured in accordance with ASTM D-1646.

Ethylene-α-olefin copolymer (a)
Is not particularly limited, and can be manufactured by a conventionally known method. For example, ethylene and the above-mentioned α-olefin can be prepared by a known method such as a solution polymerization method, a bulk polymerization method, or a gas phase polymerization method, usually at a temperature of 0 to 250 ° C. and a normal pressure to 1
It can be obtained by polymerizing under conditions of 000 atm (100 MPa). In the polymerization, it is preferable to use a single-site catalyst having a uniform polymerization active site, whereby an ethylene-α-olefin copolymer having a narrow molecular weight distribution and a narrow copolymer composition distribution, and having excellent uniformity can be easily obtained. Can be. As the single-site catalyst, a metallocene compound containing a tetravalent transition metal is preferably used. Specific examples include cyclopentadienyl titanium tris (dimethylamide), methylcyclopentadienyl titanium tris (dimethylamide), bis (Cyclopentadienyl) titanium dichloride, dimethylsilyltetramethylcyclopentadienyl t-butylamidozirconium dichloride, dimethylsilyltetramethylcyclopentadienyl t-butylamidohafnium dichloride, dimethylsilyltetramethylcyclopentadienyl-p- n-butylphenylamidozirconium dichloride, methylphenylsilyltetramethylcyclopentadienyl t-butylamidohafnium dichloride, (t-butylamide) (tetramethyl Cyclopentadienyl) -1,2-ethanediyl titanium dichloride, indenyl titanium tris (dimethylamide), indenyl titanium tris (diethylamide), indenyl titanium (di n- propyl amide)
And the like. When a metallocene compound is used as a polymerization catalyst, since it does not exhibit polymerization activity by itself, a co-catalyst such as methylaminooxane or a non-coordinating boron compound is used in an amount of 2 to 1 per mole of the metallocene compound. 2,000,000 moles, preferably 50-
It is preferable to use them together at a ratio of 5,000 mol.

The thermoplastic polyurethane (b) used in the thermoplastic elastomer composition of the present invention is, as described above,
A thermoplastic polyurethane obtained by the reaction of a polyester diol having a number average molecular weight of 1,500 to 5,000, an organic diisocyanate and a chain extender; and having a nitrogen atom content of at least 2.6% by weight. An endothermic peak by differential scanning calorimetry (DSC) of 20;
In the temperature range of 0-220 ° C; and 200-220 ° C by differential scanning calorimetry (DSC)
Enthalpy of crystallization (ΔH) determined from the endothermic peak area within the temperature range of 2 to 15 J / g.

That is, the thermoplastic polyurethane (b) used in the present invention has a number average molecular weight of 1,500 to 1,500.
It is a thermoplastic polyurethane obtained by the reaction of 5,000 polyester diol, organic diisocyanate and chain extender (requirement). When the number average molecular weight of the polyester diol used for the production of the thermoplastic polyurethane is less than 1,500, the blocking resistance of the thermoplastic elastomer composition is reduced, and sticking is likely to occur. On the other hand, the number average molecular weight of the polyester diol is
If it exceeds 0, the fluidity of the thermoplastic polyurethane decreases, the dispersibility in the ethylene-α-olefin copolymer (a) becomes poor, and the melt moldability of the obtained thermoplastic elastomer composition is poor. Become. The polyester diol used for producing the thermoplastic polyurethane (b) preferably has a number average molecular weight in the range of 1,800 to 4,000. In addition, the number average molecular weight of the polyester diol referred to in the present specification is a number average molecular weight calculated based on a hydroxyl value measured according to JIS K-1577.

As the thermoplastic polyurethane, a thermoplastic polyurethane obtained by using a polymer diol other than the polyester diol, for example, a thermoplastic polyurethane obtained by using another polymer diol such as polyether diol or polycarbonate diol is used. In this case, even if the other polymer diol has a number average molecular weight of 1,500 to
Even within the range of 5,000, the affinity between the thermoplastic polyurethane and the ethylene-α-olefin copolymer (a) is reduced, and the desired necking resistance, crack resistance,
A thermoplastic elastomer composition having excellent properties such as blocking resistance and elastic recovery after elongation cannot be obtained.

The polyester diol used for the production of the thermoplastic polyurethane (b) may be prepared by, for example, directly esterifying a diol component with a dicarboxylic acid component such as a dicarboxylic acid, an ester thereof, or an ester-forming derivative such as an anhydride according to a conventional method. Or by transesterification. Further, the polyester diol can also be produced by ring-opening polymerization of lactone.

As the dicarboxylic acid component, which is a raw material for producing the polyester diol used for producing the thermoplastic polyurethane (b), those generally used in the production of polyester diol can be used. For example, succinic acid, Glutaric acid, adipic acid, pimelic acid,
Suberic acid, azelaic acid, sebacic acid, dodecandioic acid, methylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, trimethyladipic acid, 2-methyloctanedioic acid, 3,8-dimethyldecandioic acid, 3, Aliphatic dicarboxylic acids having 4 to 12 carbon atoms such as 7-dimethyldecane diacid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid; And the like. Polyester diol is one of the dicarboxylic acid components described above.
It can be formed using species or two or more species. Among them, the polyester diol is preferably formed using an aliphatic dicarboxylic acid component having 6 to 12 carbon atoms, and may be formed using an adipic acid, azelaic acid and / or sebacic acid component. More preferred.

As the diol component, which is a raw material for producing the polyester diol used for producing the thermoplastic polyurethane (b), those generally used in the production of polyester diol can be used. Ethylene glycol, diethylene glycol,
Triethylene glycol, propylene glycol, 1,
3-propanediol, 2-methyl-1,3-propanediol, 1,3-butylene glycol, 1,4-butanediol, 2-methyl-1,4-butanediol, neopentyl glycol, 1,5-pentane Diol, 3
-Methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-
1,8-octanediol, 2,7-dimethyl-1,8
-Octanediol, 1,9-nonanediol, 2-methyl-1,9-nonanediol, 2,8-dimethyl-
1,9-nonanediol, 1,10-decanediol,
Aliphatic diols having 2 to 15 carbon atoms such as 2,2-diethyl-1,3-propanediol; alicyclics such as 1,4-cyclohexanediol, cyclohexanedimethanol, cyclooctanedimethanol, dimethylcyclooctanedimethanol; Diols; aromatic dihydric alcohols such as 1,4-bis (β-hydroxyethoxy) benzene; These diols may be used alone or in combination of two or more. Among them, 2-methyl-1,4-butanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-
Octanediol, 2-methyl-1,9-nonanediol, 2,7-dimethyl-1,8-octanediol,
It is preferable to use one or more of aliphatic diols having 5 to 12 carbon atoms and having a methyl group as a side chain, such as 2,8-dimethyl-1,9-nonanediol. In particular, the aliphatic diol having 5 to 12 carbon atoms having a methyl group as a side chain is more preferably used in an amount of 30 mol% or more, and more preferably 50 mol%, based on the total amount of the diol component forming the polyester diol. It is more preferable to use the above ratio.

In producing the polyester diol using the dicarboxylic acid component and the diol component, a titanium-based and / or tin-based polycondensation catalyst may be used. When a titanium-based catalyst is used, it is possible to deactivate the titanium catalyst contained in the polyester diol after the completion of the polycondensation reaction, so that a thermoplastic elastomer composition having excellent properties such as melt moldability and crack resistance is obtained. It is preferable in that it can be obtained.

When a titanium-based polycondensation catalyst is used in the production of the polyester diol, any of the titanium-based polycondensation catalysts conventionally used in the production of polyester can be used. For example, titanic acid, tetraalkoxytitanium compound, Examples include a titanium acylate compound and a titanium chelate compound. More specifically, tetraisopropyl titanate, tetra n-butyl titanate,
Tetraalkoxytitanium compounds such as tetra-2-ethylhexyl titanate and tetrastearyl titanate;
Polyhydroxytitanium stearate, titanium acylate compounds such as polyisopropoxytitanium stearate,
Examples thereof include titanium chelate compounds such as titanium acetylacetonate, triethanolamine titanate, titanium ammonium lactate, titanium ethyl lactate, and titanium octylene glycol. The amount of the titanium-based polycondensation catalyst is not particularly limited, but is generally preferably in the range of about 0.1 to 50 ppm, and more preferably about 1 to 30 ppm, based on the total amount of the reaction components for forming the polyester diol. More preferably, it is within the range.

As a method for deactivating the titanium-based polycondensation catalyst contained in the produced polyester diol, for example, a method in which the polyester diol obtained by the esterification reaction is brought into contact with water under heating to deactivate the polyester diol, A method of treating a diol with a phosphorus compound such as phosphoric acid, a phosphoric acid ester, a phosphorous acid, or a phosphite may be used. In the case where the titanium-based polycondensation catalyst is deactivated by contact with water, water is added to the polyester diol obtained by the esterification reaction in an amount of 1% by weight or more, and 70 to 15%.
The heating may be performed at a temperature of 0 ° C, preferably 90 to 130 ° C for 1 to 3 hours. The deactivation of the titanium-based polycondensation catalyst may be performed under normal pressure or under pressure. The added water can be removed by depressurizing the system after deactivating the titanium-based polycondensation catalyst.

The lactone which can be used as a raw material for producing the polyester diol used for producing the thermoplastic polyurethane (b) includes, for example, ε-caprolactone, β-methyl-δ-valerolactone and the like. A polyester diol can be obtained by performing ring-opening polymerization using these lactones using a diol or the like as an initiator.

In the production of the polyester diol used for the production of the thermoplastic polyurethane (b), glycerin, trimethylolpropane, butanetriol, hexanetriol, trimethylol may be used, if necessary, within a range not to impair the object of the present invention. A small amount of a polyol such as butane or pentaerythritol or a trifunctional or higher polycarboxylic acid or an ester-forming derivative thereof may be used.

The type of the organic diisocyanate used for producing the thermoplastic polyurethane (b) is not particularly limited.
Any of aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate conventionally used for the production of thermoplastic polyurethane may be used.For example, 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, Aromatic diisocyanates such as xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3'-dichloro-4,4'-diphenylmethane diisocyanate; hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenation Examples thereof include aliphatic or alicyclic diisocyanates such as xylylene diisocyanate. These organic diisocyanates may be used alone or in combination of two or more. Among them, 4,4'-diphenylmethane diisocyanate is preferably used.

The chain extender used for producing the thermoplastic polyurethane (b) is not particularly limited, and any chain extender conventionally used for producing a thermoplastic polyurethane may be used. A low molecular weight compound having two active hydrogen atoms capable of reacting with an isocyanate group in a molecule is preferably used. Examples of such chain extenders include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol And diols such as bis (β-hydroxyethyl) terephthalate and xylylene glycol; hydrazine, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine and derivatives thereof, phenylenediamine, tolylenediamine, xylenediamine, adipic dihydrazide And diamines such as isophthalic acid dihydrazide; and amino alcohols such as aminoethyl alcohol and aminopropyl alcohol. These low molecular compounds may be used alone or in combination of two or more. Among them, aliphatic diols having 2 to 10 carbon atoms are preferably used,
-Butanediol is more preferably used.

In the production of the thermoplastic polyurethane (b), the ratio of [the total number of moles of active hydrogen atoms of the polyester diol and the chain extender]: [the number of moles of isocyanate groups based on the organic diisocyanate] is:
It is preferable to carry out the reaction using the polyester diol, the organic diisocyanate and the chain extender in an amount such that the ratio becomes 1: 0.9 to 1.2. By using the thermoplastic polyurethane (b) thus produced, a thermoplastic elastomer composition having excellent melt moldability and blocking resistance can be obtained.

The method for producing the thermoplastic polyurethane (b) is not particularly limited, and the polyester diol, the organic diisocyanate and the chain extender described above are used in the absence of a solvent by utilizing a known urethanation reaction technique. Alternatively, in the presence, it may be produced by either the prepolymer method or the one-shot method. Among them, a method of producing a thermoplastic polyurethane (b) by performing melt polymerization in a state substantially free of a solvent is preferably employed. In particular, it is more preferable to produce the thermoplastic polyurethane (b) by employing a continuous melt polymerization method using a multi-screw extruder in the absence of a solvent or a belt-type prepolymer method. By using the thermoplastic polyurethane (b) thus obtained, a thermoplastic elastomer composition having excellent blocking resistance can be obtained.

It is necessary that the thermoplastic polyurethane (b) used in the present invention further satisfies not only the above requirements but also the requirement that the nitrogen atom content is at least 2.6% by weight. When the nitrogen content of the thermoplastic polyurethane is less than 2.6% by weight, the thermoplastic elastomer composition obtained by blending such a thermoplastic polyurethane with the ethylene-α-olefin copolymer (a) has a high durability. The blocking property is inferior. The thermoplastic polyurethane (b) has a nitrogen atom content of 2.6 to 6.
It is preferably in the range of 0% by weight, and 2.8 to 5.
More preferably, it is within the range of 3.0% by weight.
More preferably, it is within the range of 4.0% by weight. In addition, the nitrogen atom content of the thermoplastic polyurethane referred to in the present specification is the nitrogen atom content obtained from the elemental analysis of the thermoplastic polyurethane. The thermoplastic polyurethane (b) having a nitrogen atom content of 2.6% by weight or more can be obtained by adjusting the molecular weight of polyester diol, an organic diisocyanate and a chain extender which are raw materials for producing the thermoplastic polyurethane (b), It can be obtained by adjusting the type and amount of the elongating agent.

Further, the thermoplastic polyurethane (b) used in the present invention has an endothermic peak in the temperature range of 200 to 220 ° C. according to differential scanning calorimetry (DSC) (requirement), and a differential scanning calorimetry (DSC). 20 by
It is necessary that the crystallization enthalpy (ΔH) determined from the endothermic peak area in the temperature range of 0 to 220 ° C. is in the range of 2 to 15 J / g (requirement). The endothermic peak of the thermoplastic polyurethane is less than 200 ° C.,
And / or the crystallization enthalpy (ΔH) is 2J
If it is less than / g, the thermoplastic elastomer composition obtained by blending such a thermoplastic polyurethane has poor melt moldability and blocking resistance. on the other hand,
If the endothermic peak of the thermoplastic polyurethane is above 220 ° C. and / or the enthalpy of crystallization (Δ
When H) exceeds 15 J / g, the thermoplastic elastomer composition obtained by blending such a thermoplastic polyurethane tends to generate an unmelted substance when melted, and a film or sheet obtained therefrom may be used. Bubbles (fish eyes) are generated in the molded product, the smoothness of the surface is lost, the appearance and the mechanical properties are deteriorated, and the blocking resistance is reduced.

The thermoplastic polyurethane (b) used in the present invention has an endothermic peak in the temperature range of 200 to 220 ° C. by differential scanning calorimetry (DSC) and 200 to 220 ° C. in differential scanning calorimetry (DSC). More preferably, the crystallization enthalpy ([Delta] H) determined from the endothermic peak area within the temperature range is in the range of 3 to 10 J / g. The specific method of measuring the temperature of the endothermic peak by differential scanning calorimetry (DSC) and the method of determining the crystallization enthalpy (ΔH) in this specification are as described in the following Examples. The thermoplastic polyurethane (b) satisfying the requirements and requirements is
Although not limited, for example, the molecular weight of the polyester diol, the organic diisocyanate and the chain extender, which are the raw materials for producing the thermoplastic polyurethane (b), and the type and the amount of the organic diisocyanate and the chain extender are adjusted. Can be obtained by:

The viscosity of the thermoplastic polyurethane (b) may vary depending on the types of polyester diol, organic diisocyanate and chain extender used in the production thereof, the nitrogen atom content in the thermoplastic polyurethane (b), and the like. Generally, when a solution obtained by dissolving thermoplastic polyurethane (b) in N, N-dimethylformamide and having a concentration of 0.5 g / dl is measured at 30 ° C., its logarithmic viscosity is 0.2 to It is preferably in the range of 1.2 dl / g, more preferably in the range of 0.3 to 1.1 dl / g, and more preferably in the range of 0.5 to 1.1 dl / g. preferable. By using the thermoplastic polyurethane (b) having the above-mentioned logarithmic viscosity, the thermoplastic elastomer composition of the present invention has more excellent melt moldability and blocking resistance.

The thermoplastic elastomer composition of the present invention comprises the above-mentioned ethylene-α-olefin copolymer (a) and the thermoplastic polyurethane (b) satisfying the above requirements (1) to (4) The weight ratio of copolymer (a): thermoplastic polyurethane (b) is 7
It is necessary to contain it in the range of 0:30 to 90:10, and it is preferable to contain it in the range of 75:25 to 85:15.

Ethylene-α-olefin copolymer (a)
And the total weight of the thermoplastic polyurethane (b)
When the content of the ethylene-α-olefin copolymer (a) is 7
In the case of a thermoplastic elastomer composition having a content of less than 0% by weight [the content of the thermoplastic polyurethane (b) exceeds 30% by weight], a molded article such as a film having a small thickness and a good surface condition. Cannot be obtained, and the blocking resistance is poor. On the other hand, an ethylene-α-olefin copolymer (a) and a thermoplastic polyurethane (b)
Thermoplastic elastomers having a content of ethylene-α-olefin copolymer (a) of more than 90% by weight and a content of thermoplastic polyurethane (b) of less than 10% by weight, based on the total weight of In the case of the composition, when extruding into a film or sheet using a T-die extruder or the like, the necking phenomenon becomes severe and the width of the film or sheet becomes narrow, and as a result, the film or sheet becomes The range of thickness unevenness generated at both ends is widened, and the width of a product obtained by trimming the thick portion becomes extremely narrow, resulting in a large decrease in yield. In addition, the thermoplastic elastomer composition and the molded article have poor blocking resistance.

The thermoplastic elastomer composition of the present invention comprises:
The ethylene-α-olefin copolymer (a) and the thermoplastic polyurethane (b) satisfying the above requirements (1) and (2) are mixed in a weight ratio of ethylene-α-olefin copolymer (a): thermoplastic polyurethane (b). 70:30 to 90:
As long as the thermoplastic elastomer composition is contained so as to fall within the range of 10, if necessary, another thermoplastic polymer may be used in a small amount, preferably an ethylene-α-olefin copolymer (a) and It may be contained in a proportion of 10% by weight or less based on the total weight of the plastic polyurethane (b). Such other thermoplastic polymers include, for example, thermoplastic polyurethanes that do not meet one or more of the above requirements (i.e., thermoplastic polyurethanes other than thermoplastic polyurethane (b)) And polyolefins such as polyethylene and polypropylene.

The thermoplastic elastomer composition of the present invention may further contain a reinforcing agent, a coloring agent, a lubricant, a pressure-sensitive adhesive, a flame retardant, a weather resistance improver, and an ultraviolet ray as long as the effects of the present invention are not impaired. Various additives such as absorbents, antioxidants, hydrolysis resistance improvers, fungicides, antibacterial agents, and stabilizers; various fibers such as glass fibers and polyester fibers; inorganic materials such as talc and silica; various coupling agents And the like. These components are ethylene-
It can be added during or after the production of the α-olefin copolymer (a), during or after the production of the thermoplastic polyurethane (b), and / or during the preparation of the thermoplastic elastomer composition.

The method for preparing the thermoplastic elastomer composition of the present invention is not particularly limited, and any method conventionally used for preparing a thermoplastic polymer composition may be used. For example, using a vertical or horizontal mixer as generally used for mixing resin materials, ethylene-α-olefin copolymer (a), thermoplastic polyurethane (b), and other After pre-mixing the thermoplastic polymer and other components in a predetermined ratio, melt-kneading is performed batchwise or continuously using a single-screw or twin-screw extruder, mixing roll, Banbury mixer, etc. By doing so, the thermoplastic elastomer composition of the present invention can be obtained. The melt-kneading temperature in that case may vary depending on the type of the ethylene-α-olefin copolymer (a) or the thermoplastic polyurethane (b) used, but generally a temperature of 120 to 270 ° C is preferably employed. . As another method, an ethylene-α-olefin copolymer (a) and, if necessary, another thermoplastic polymer and other components are blended at a later stage of polymerization when producing the thermoplastic polyurethane (b). To prepare a thermoplastic elastomer composition.

The thermoplastic elastomer composition of the present invention comprises:
Melt molding and heat processing are possible, and various molding methods generally used for thermoplastic polymers, such as extrusion molding, injection molding, blow molding, calender molding, press molding, vacuum molding, injection molding By melt spinning, various molded articles and products such as films, sheets, plates, tubular articles, rod-shaped articles, various block-shaped molded articles, hollow molded articles, tray-shaped molded articles, and fibers can be smoothly manufactured. . Although not limited, for example, in the case of molding and spinning techniques involving melting such as extrusion molding, injection molding, blow molding, and melt spinning, generally, a melting temperature of 150 to 200 ° C. is preferably employed. .

In particular, the thermoplastic elastomer composition of the present invention is excellent in melt moldability. For example, when producing a film or sheet using a T-die extruder,
Necking in the extruded film or sheet is greatly reduced, cracking does not occur, and as a result, the proportion of thickness unevenness at both ends of the film or sheet also decreases. The width of the product to be manufactured is large, and the target product such as a film or sheet can be manufactured with high yield and high productivity.
Moreover, the resulting molded products such as films and sheets have no sticking and have excellent blocking resistance.
Even if it is wound as it is, it does not stick to each other and can be easily rewound later, eliminating the need for expensive release paper,
Also, there is no need to use a large amount of lubricant that may seep out. In addition, films, sheets, and other molded products obtained using the thermoplastic elastomer composition of the present invention include:
Smooth and good surface condition, excellent flexibility, stretchability, elastic recovery, low residual strain after elongation, excellent mechanical properties such as tensile breaking strength and tensile breaking elongation, moderate High strength.

Therefore, molded articles, particularly sheets and films, obtained from the thermoplastic elastomer composition of the present invention are:
By utilizing the above-mentioned excellent properties, it can be effectively used as a stretchable film (sheet) used for a sanitary napkin, a disposable diaper, a sealing material, a dustproof material, and the like. Further, the thermoplastic elastomer composition of the present invention,
Not limited to the above-mentioned applications, for example, various conveyor belts,
It can also be used effectively for applications such as keyboard sheets and various containers. Further, the thermoplastic elastomer composition of the present invention is also suitable for producing a laminate with a nonwoven fabric or other fibrous base material, a laminate with another polymer film or a base material such as a sheet, and the like. Can be easily obtained by, for example, melt-extruding the thermoplastic elastomer composition of the present invention into a film or sheet on a fibrous substrate or another substrate.

[0045]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto. In the following Examples and Comparative Examples, the nitrogen content of the thermoplastic polyurethane, the logarithmic viscosity, the endothermic peak temperature by differential scanning calorimetry (DSC), and the endothermic temperature in the temperature range of 200 to 220 ° C. by differential scanning calorimetry (DSC). Crystallization enthalpy (Δ
H), melt moldability of the thermoplastic elastomer composition, state of the film at the time of extrusion (ease of winding), appearance of the film, blocking resistance, 100% modulus (M
100) and residual strain were measured or evaluated by the following methods.

(1) Nitrogen atom content of thermoplastic polyurethane: Elemental analyzer (Perkin Elmer “240-
Elemental analysis of the thermoplastic polyurethane was performed using "type 2") to determine its nitrogen atom content (% by weight).

(2) Logarithmic viscosity of thermoplastic polyurethane:
A thermoplastic polyurethane solution having a concentration of 0.5 g / dl is prepared by dissolving a thermoplastic polyurethane in N, N-dimethylformamide, and the above-prepared thermoplastic polyurethane solution is allowed to flow at 30 ° C. using an Ubbelohde viscometer. The time was measured, and the logarithmic viscosity of the thermoplastic polyurethane was determined by the following equation.

[0048]

## EQU1 ## Logarithmic viscosity (dl / g) of thermoplastic polyurethane =
_{{Ln (t / t 0)} } / c [ where, t is a thermoplastic polyurethane solution flow time (in seconds), t _o a solvent (N, N-dimethylformamide)
And c indicates the concentration of the thermoplastic polyurethane (0.5 g / dl). ]

(3) Endothermic peak temperature and enthalpy of crystallization (ΔH) of thermoplastic polyurethane measured by differential scanning calorimetry (DSC): (i) Differential scanning calorimeter (“DSC3” manufactured by METTLER COMPANY)
0 ”), using about 10 mg of thermoplastic polyurethane, heating at a rate of 10 ° C./min in a nitrogen gas atmosphere and measuring its melting enthalpy to determine an endothermic peak (° C.). . (Ii) In the measurement of the enthalpy of fusion of the thermoplastic polyurethane in the above (i), the measurement was performed at 200 to 220 ° C.
The crystallization enthalpy (ΔH) (J / g) was determined from the endothermic peak area in the temperature range described above.

(4) Melt moldability of thermoplastic elastomer composition (thermoplastic elastomer): T-die single-screw extrusion molding using thermoplastic elastomer compositions (thermoplastic elastomers) of the following Examples and Comparative Examples. Machine (25mm
φ: Die effective width 350mm, lip gap 0.3mm)
, A film was produced by extrusion under the conditions described in the following Examples and Comparative Examples, and the film width (W ₂ ) (mm) at 10 cm downstream from the T-die exit was measured. From the relationship with the effective width (W ₁ ) (mm), the necking ratio (%) of the extruded film was determined by the following formula, and was used as an index of melt moldability.

[0051]

## EQU2 ## Necking rate (%) of film = ｛(W ₁ −
W ₂ ) / W ₁ ｝ × 100

(5) State of film during extrusion (ease of winding): A film extruded from a T-die extruder was cooled by contact with a cooling roll having a surface temperature of 30 ° C. The film was wound as it was at a winding speed of about 3 m / min without using the film. During the winding, the state of the film was visually observed.
Were evaluated according to the criteria shown in Table 1.

[0053]

[Table 1] ：: No defective phenomenon such as necking or cracking occurred in the film, and the film could be wound smoothly. Δ: The film is somewhat defective, such as necking or cracking, but can be wound up. ×: Inferior phenomena such as necking and cracks in the film were severe, and winding was impossible.

(6) Appearance of film: In the above-mentioned (5), in the case of a film that cannot be wound or a film that cannot be wound, the surface condition of the film immediately before the winder is visually observed. Smooth ones were evaluated as good (O), and those having irregularities on the surface due to poor dispersion between polymers were evaluated as poor (X).

(7) Blocking resistance of the film: The film-like material extruded from the T-die extruder was subjected to a surface temperature of 30 ° C.
After being cooled by contact with a cooling roll, the film was wound at a winding speed of about 3 m / min without using release paper to produce a film. After leaving the wound film at room temperature for 24 hours, the film was rewound by hand, and the anti-blocking property was evaluated according to the criteria shown in Table 2 below based on the magnitude of the resistance at that time.

[0056]

[Table 2] ：: Unwinding is extremely easy without requiring any tensile force. ：: Although some tensile force is required, rewinding can be performed almost smoothly. Δ: A considerable tensile force is required, but rewinding is possible. X: The adhesive force is large, and rewinding by hand is impossible.

(8) 100% modulus of film (M
100): Thickness 3 manufactured using a T-die extruder
From a 0 μm film to a test piece (length × width = 20 cm × 5
cm) from the test piece, and stretched at room temperature at a tensile speed of 300 mm / min using an autograph measuring device (“IS-500D” manufactured by Shimadzu Corporation) at room temperature.
Modulus (M100) at 0% elongation (kgf /
cm ² ) was measured.

(9) Residual strain of film: A test piece (length × width = 20 cm × 5 cm) was sampled from a 30 μm-thick film manufactured by using a T-die extruder, and this test piece was used. Using an autograph measuring device (“IS-500D” manufactured by Shimadzu Corporation), a tensile speed of 3 at room temperature was used.
100% elongation at 00 mm / min, then return to the position before elongation at 300 mm / min (1st cycle), continue 100% elongation again at the same speed, then return to the position before elongation at the same speed (Second cycle) At this point (second cycle), the length of the test piece was measured, and the residual strain (%) of the film was determined from the following equation.

[0059]

## EQU3 ## Residual strain (%) of film = ₂ (L ₂ −L ₁ ) /
L ₁ ｝ × 100 [where L ₁ is the length of the test piece before elongation (20 c
m), L ₂ represents the length of the second cycle after the end of the test piece (cm). ]

The abbreviations and contents of the polymers used in the following Examples and Comparative Examples are as shown below. [Ethylene-α-olefin copolymer (a)] POE-A : ethylene-1-octene copolymer [“ENGAGE EG81 manufactured by DuPont Dow Elastomer Co., Ltd.”
00 ", molar ratio of ethylene units / 1-octene units = 9
2.7 / 7.3, melt index (190 ° C, 2.
16 kg load) = 1.0 g / 10 min, Shore A hardness =
75, Mooney viscosity = 35.6 ML _{1 + 4} (100 ° C)]. -POE -B : an ethylene-1-octene copolymer [Engage EG81 manufactured by Dupont Dow Elastomer Co., Ltd.]
50 ", molar ratio of ethylene units / 1-octene units = 9
2.5 / 7.5, melt index (190 ° C, 2.
16 kg load) = 0.4 g / 10 min, Shore A hardness =
75, Mooney viscosity = 52.1 ML _{1 + 4} (100 ° C)].

[Thermoplastic polyurethane] TPU-A : Polyester diol comprising 3-methyl-1,5-pentanediol and adipic acid (number average molecular weight = 3,500) / 4,4'-diphenylmethane diisocyanate / 1, Thermoplastic polyurethane obtained by reaction of 4-butanediol [nitrogen atom content = 3.2% by weight, endothermic peak temperature by differential scanning calorimetry (DSC) = 204 ° C., crystallization enthalpy (ΔH) = 3.5 J /
g, logarithmic viscosity = 0.75 dl / g]. TPU-B : polyester diol (number-average molecular weight = a mixture of 1,4-butanediol and 1,6-hexanediol (molar ratio = 60: 40) and adipic acid)
(2,000) / 4,4'-diphenylmethane diisocyanate / 1,4-butanediol thermoplastic polyurethane [nitrogen atom content = 3.1% by weight, endothermic peak temperature by differential scanning calorimetry (DSC)] = 20
6 ° C., crystallization enthalpy (ΔH) = 5.3 J / g, logarithmic viscosity = 1.01 dl / g].

TPU-C : polyester diol composed of 3-methyl-1,5-pentanediol and adipic acid (number average molecular weight = 3,500) / 4,4′-diphenylmethane diisocyanate / 1,4-butanediol Thermoplastic polyurethane obtained by reaction [nitrogen atom content = 2.4% by weight, endothermic peak temperature by differential scanning calorimetry (DSC) = 171 ° C., enthalpy of crystallization (ΔH)
= 8.8 J / g, logarithmic viscosity = 1.38 dl / g]. TPU-D : polyester diol comprising 1,4-butanediol and adipic acid (number average molecular weight = 1,00
0) / 4,4′-diphenylmethane diisocyanate /
Thermoplastic polyurethane obtained by the reaction of 1,4-butanediol [nitrogen atom content = 4.4% by weight, endothermic peak temperature by differential scanning calorimetry (DSC) = 175 ° C., crystallization enthalpy (ΔH) = 0 J / g, logarithmic viscosity = 0.
90 dl / g]. * TPU-E : 1,9-nonanediol and 2-methyl-
Mixture of 1,8-octanediol (molar ratio = 65: 3
5) Thermoplastic polyurethane obtained by the reaction of polyester diol composed of adipic acid (number average molecular weight = 2,000) / 4,4′-diphenylmethane diisocyanate / 1,4-butanediol [nitrogen atom content = 4.3.
Weight%, endothermic peak temperature by differential scanning calorimetry (DSC) = 228 ° C., crystallization enthalpy (ΔH) = 20.
5 J / g, logarithmic viscosity = 0.70 dl / g].

Example 1 (1) As shown in Table 3 below, POE-A and TPU
-A was premixed at a ratio of 80 parts by weight: 20 parts by weight, and then the mixture was supplied to a single screw extruder, melt-kneaded at 200 ° C, extruded into strands, cut, and cut to give a thermoplastic elastomer composition. Pellets were produced. (2) The pellets of the thermoplastic elastomer composition obtained in the above (1) are extruded into a single-screw T-die extruder (25 m
mφ, cylinder temperature 180-200 ° C, die temperature 2
(00 ° C.), melt-kneaded, extruded from the T-die into a film, cooled by contacting with a cooling roll having a surface temperature of 30 ° C., and wound up about 3 m / min without using release paper. The film was produced by winding at a speed. (3) Melt moldability of the thermoplastic elastomer composition at the time of the extrusion molding in the above (2), state of the film (ease of winding), appearance of the obtained film, blocking resistance, modulus of 100% (M100) When the residual strain was measured or evaluated by the method described above, the results were as shown in Table 3 below.

Examples 2 to 5 (1) The ethylene-α-olefin copolymer (a) shown in Table 3 below and the thermoplastic polyurethane were premixed in the proportions shown in Table 3, and then the mixture was simply mixed. The mixture was fed to a screw extruder, melt-kneaded at 200 ° C., extruded into strands, and cut to produce pellets of a thermoplastic elastomer composition. (2) Using a pellet of the thermoplastic elastomer composition obtained in (1) above, a film was produced using a T-die extruder in the same manner as in (2) of Example 1. (3) Melt moldability of the thermoplastic elastomer composition at the time of the extrusion molding in the above (2), state of the film (ease of winding), appearance of the obtained film, blocking resistance, modulus of 100% (M100) When the residual strain was measured or evaluated by the method described above, the results were as shown in Table 3 below.

<< Comparative Examples 1 to 6 >> (1) After pre-mixing the ethylene-α-olefin copolymer (a) shown in Table 3 below and the thermoplastic polyurethane in the ratio shown in Table 3, a single screw extruder was used. And melt-kneaded at 200 ° C., extruded into strands, and cut to produce pellets of a thermoplastic elastomer composition.
5) (Comparative Example 6 uses only POE-A). (2) Pellets of the thermoplastic elastomer composition obtained in the above (1) (Comparative Examples 1 to 5) or ethylene-α-
The olefin copolymer (POE-A) (Comparative Example 6) was fed to a single-screw T-die extruder (25 mmφ, cylinder temperature 180 to 200 ° C, die temperature 200 ° C) and melt-kneaded. The film was extruded from the T-die into a film form, contacted with a cooling roll having a surface temperature of 30 ° C., cooled, and then wound up at a winding speed of about 3 m / min without using release paper to produce a film. (3) Melt moldability of the thermoplastic elastomer composition at the time of the extrusion molding in the above (2), state of the film (ease of winding), appearance of the obtained film, blocking resistance, modulus of 100% (M100) When the residual strain was measured or evaluated by the method described above, the results were as shown in Table 3 below.

[0066]

[Table 3]

From the results in Table 3 above, the thermoplastic elastomer compositions of Examples 1 to 5, ie, ethylene-α-
The olefin copolymer (a) and the thermoplastic polyurethane (b) (TPU-A or TPU-B) satisfying the above requirements are specified in the present invention at 70:30 to 90:
The thermoplastic elastomer composition contained at a weight ratio of 10 has a low necking ratio at the time of extrusion molding of a film and is excellent in melt moldability, and further has an excellent state of a film at the time of extrusion molding (ease of winding). You can see that there is. In addition, the films obtained in Examples 1 to 5 had smooth surfaces and excellent appearance, had no sticking, had excellent blocking resistance, and could be smoothly wound and unwound. It can be seen that the modulus (M100) is in an appropriate range and has an appropriate flexibility, and that the elastic recovery is excellent and the residual strain is small even after elongation. And the result of Example 5 is ethylene-α-
An olefin copolymer (a) and a thermoplastic polyurethane (b) satisfying the above-mentioned requirements (1) to 70:30 to 90: 1
In the thermoplastic elastomer composition of the present invention containing a weight ratio of 0, even if it contains some thermoplastic polyurethane (TPU-C in Example 5) other than the thermoplastic polyurethane (b), its excellent properties are as follows. It shows that it is not damaged at all.

On the other hand, the thermoplastic elastomer compositions of Comparative Examples 1 to 5 and the polymer of Comparative Example 6, ie, the ethylene-α-olefin copolymer (a), which do not satisfy the various requirements in the present invention, Thermoplastic polyurethane that does not satisfy any of the following requirements (TPU-
Comparative Example 1 containing only C, TPU-D and TPU-E)
Thermoplastic polyurethanes (TPU-A, TPU-A) which satisfy the above requirements (1) to (3) of the thermoplastic elastomer composition and the ethylene-α-olefin copolymer (a).
The thermoplastic elastomer compositions of Comparative Examples 4 and 5 in which the compounding amount of B) is out of the above-mentioned range of the weight ratio of 70:30 to 90:10 specified in the present invention even when compounded, and In Comparative Example 6 consisting solely of the ethylene-α-olefin copolymer (a), the necking ratio during extrusion molding of the film was large and the melt moldability was poor.
The state of the film at the time of extrusion molding (rewindability) is inferior, the obtained film has irregularities on the surface and is inferior in appearance, or the sticking is strong and the blocking resistance is inferior, making it difficult or impossible to rewind. It can be seen that it is possible, that the value of the modulus (M100) of 100% is not appropriate and does not have appropriate flexibility, and / or that the elastic recovery is poor and the residual strain after elongation is large.

[0069]

Since the thermoplastic elastomer composition of the present invention is excellent in melt moldability, when a molded article such as extrusion molding is performed using the thermoplastic elastomer composition of the present invention, necking phenomena, cracking, etc. Thus, molded products such as films and sheets having excellent appearance and physical properties can be produced with high yield and high productivity without causing the problem. Furthermore, since the thermoplastic elastomer composition of the present invention has no blocking and excellent blocking resistance, the thermoplastic elastomer composition of the present invention can be used without blending a large amount of a lubricant and further without using a release paper. Using the product, a molded product such as a film or a sheet that can be easily wound or unwound can be manufactured smoothly. And, the thermoplastic elastomer composition of the present invention and a molded product obtained using the same have excellent properties inherent to the ethylene-α-olefin copolymer, particularly, flexibility and elastic recovery. It has moderate strength, small residual strain after elongation, and has excellent functions as a thermoplastic elastomer. The thermoplastic elastomer composition of the present invention can be effectively used in a wide range of applications by utilizing the above-mentioned various excellent properties.

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Claims (4)

[Claims] (I) An ethylene-α-olefin copolymer (a) and a thermoplastic polyurethane (b) are obtained by mixing the ethylene-α-olefin copolymer (a) and the thermoplastic polyurethane (b) with 70:30. (Ii) a thermoplastic elastomer composition containing the composition in a weight ratio of 〜90: 10;
The thermoplastic polyurethane (b) is a thermoplastic polyurethane obtained by a reaction of a polyester diol having a number average molecular weight of 1,500 to 5,000, an organic diisocyanate and a chain extender; The amount is 2.6% by weight or more; Endothermic peak by differential scanning calorimetry (DSC) is 20
In the temperature range of 0-220 ° C; and 200-220 ° C by differential scanning calorimetry (DSC)
A thermoplastic elastomer composition characterized by having a crystallization enthalpy (ΔH) determined from an endothermic peak area in a temperature range of 2 to 15 J / g; 2. The ethylene-α-olefin copolymer (a) is a copolymer of ethylene and an α-olefin having 4 or more carbon atoms, and a unit derived from ethylene in the copolymer: α The thermoplastic elastomer composition according to claim 1, wherein the molar ratio of units derived from olefin is 55:45 to 99: 1. 3. A molded article comprising the thermoplastic elastomer composition according to claim 1. 4. The molded article according to claim 3, which is a film or a sheet.