JP2007023299A - Thermoplastic elastomer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition holding flexibility, elastic recovery or the like originally possessed by an ethylene-α-olefin copolymer, having excellent melt moldability, hardly causing necking, breakage, agglutination or the like, and having excellent appearance, blocking resistance, strength, low residual strain after extension, or the like; and to provide a molded product comprising the same. <P>SOLUTION: The thermoplastic elastomer composition contains (a) an ethylene-α-olefin copolymer and (b) a thermoplastic polyurethane satisfying the following conditions (i) to (iv) in a ratio of components (a) to (b) being (70:30)-(90:10): (i) obtained by the reaction of a polyester diol having 1,500-5,000 number average molecular weight with an organic diisocyanate and a chain extender; (ii) having ≥2.6 wt.% nitrogen atom content; (iii) having an endothermic peak by a DSC within the range of 200-220°C; and (iv) having 2-15 J/g crystallization enthalpy (ΔH) by the DSC within the temperature range of 200-220°C. The molded product comprises the composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermoplastic elastomer composition mainly composed of 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 a film or sheet is produced using a T-die type extrusion molding machine, the necking phenomenon or cracking in which the width of the film or sheet becomes narrower. The product can be obtained at a high yield, and it is difficult to agglomerate and has excellent blocking resistance, preventing blocking of molded products without using a large amount of lubricant or release paper. For example, film and sheet can be smoothly wound and unwound. In addition, since the ethylene-α-olefin copolymer and the specific thermoplastic polyurethane are uniformly dispersed in the thermoplastic elastomer composition of the present invention, the molded product such as a film or a sheet obtained therefrom is uneven. It has a smooth and excellent appearance free from rust and fish (fisheye), moderate strength, excellent elasticity recovery, small residual strain after stretching, and can be used effectively as a stretchable material.

Despite its elasticity, thermoplastic elastomer compositions do not require vulcanization as in natural rubber and diene rubber, and can be melt-molded and heat-processed in the same way as thermoplastic resins. Since it is excellent in 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, taking advantage of these characteristics.
Various thermoplastic elastomer compositions have been proposed in the past. Among them, ethylene-α- for thermoplastic resins such as thermoplastic polyurethane, polyvinyl chloride, styrene polymer, polyolefin and the like. A thermoplastic polyolefin-based elastomer composition containing an olefin copolymer is known. For example, Patent Document 1 discloses a specific melt flow for thermoplastic materials such as thermoplastic polyurethane, polyvinyl chloride, styrene polymer, and polyolefin for the purpose of improving impact resistance and transparency at low temperatures. A thermoplastic olefin-based polymer composition blended with an ethylene-α-olefin copolymer having a ratio, molecular weight distribution (Mw / Mn) and critical shear temperature is described.

However, in the above-described conventional thermoplastic polyolefin-based elastomer composition, including those described in Patent Document 1, characteristics such as flexibility inherent in the ethylene-α-olefin copolymer are impaired. There are many cases. In addition, when a film or sheet is produced using a conventional thermoplastic polyolefin-based elastomer composition using a T-die extruder, the necking phenomenon in which the width of the film or sheet is reduced, the film or sheet is cracked. Therefore, a film or sheet product obtained by trimming both ends with thick spots has a problem that the width is extremely narrow or a defective product with cracks is produced, resulting in a low product yield. In addition, the molded product obtained there has a strong agglutination property, and in order to prevent agglutination (blocking), it is necessary to add a large amount of lubricant or wind up the film or sheet together with an expensive release paper. In addition, there are problems such as the problem of the seepage of the lubricant onto the surface of the molded product due to the use of the lubricant, and the complicated labor and cost associated with the combined use of the release paper.
JP-T 8-501343

The object of the present invention is to provide excellent properties inherent to ethylene-α-olefin copolymers, in particular, flexibility and elastic recovery, and excellent melt moldability, such as necking and cracking. To provide a thermoplastic elastomer composition based on an ethylene-α-olefin copolymer, which can produce molded products such as films and sheets having excellent appearance and physical properties with high yield and high productivity without any occurrence. It is.
The object of the present invention is, in addition to the above-mentioned characteristics, excellent in anti-blocking property without sticking, and without using a large amount of lubricant or without using release paper in combination, such as a film or sheet It is to provide a thermoplastic elastomer composition based on an ethylene-α-olefin copolymer, which can smoothly wind or unwind the molded article.
Furthermore, the object of the present invention is to smoothly produce a molded article such as a film or sheet having the above-described excellent characteristics, moderate strength, excellent elastic recovery, and small residual strain after elongation. It is an object of the present invention to provide a thermoplastic elastomer composition based on an ethylene-α-olefin copolymer.
And this invention is providing the molded article which consists of an above described thermoplastic elastomer composition.

  As a result of the inventor's repeated studies to achieve the above object, in the conventional thermoplastic polyolefin-based elastomer composition as described in Patent Document 1 described above, an ethylene-α-olefin copolymer and As the thermoplastic resin to be used in combination, thermoplastic resins such as thermoplastic polyurethane and polypropylene having a low crystal melting temperature are used, and as a result, the above-mentioned necking phenomenon and cracking in the production of films and sheets are caused. It has been found that problems, blocking (sticking) problems in molded products, etc. are likely to occur, and that the recovery stress after elongation of the molded product obtained is small and the residual strain after elongation is large.

  Therefore, the present inventor has further studied based on the above findings found by the present inventor. As a result, polyester-based thermoplastic polyurethane having specific physical properties with respect to the ethylene-α-olefin copolymer, that is, polyester-based thermoplastic having specific nitrogen atom content, crystal melting temperature and crystallization enthalpy (ΔH) When polyurethane is blended at a specific ratio, the resulting thermoplastic elastomer composition is a necking phenomenon in which the width of the film or sheet becomes narrower when a film or sheet is produced using a T-die type extruder or the like. In addition, the film and sheet are prevented from cracking, and there is no unevenness or irregularity (fish eye), and the appearance is excellent. Further, the thermoplastic elastomer composition and the molded article made thereof are free from sticking. Excellent blocking resistance and smooth winding without using a large amount of lubricant or release paper In addition, it has been found that molded articles obtained from the thermoplastic elastomer composition have moderate strength, excellent elasticity recovery, and low residual strain after elongation. Based on these findings, the present invention has been completed.

That is, the present invention relates to (1) ethylene-α-olefin copolymer (a) and thermoplastic polyurethane (b), ethylene-α-olefin copolymer (a): thermoplastic polyurethane (b) = 70: A thermoplastic elastomer composition containing a weight ratio of 30 to 90:10; and (2) the thermoplastic polyurethane (b) comprises the following requirements (i) to (iv):
(I) a thermoplastic polyurethane obtained by reaction of a polyester diol having a number average molecular weight of 1,500 to 5,000, an organic diisocyanate and a chain extender;
(Ii) the nitrogen atom content is 2.6% by weight or more;
(Iii) the endothermic peak by differential scanning calorimetry (DSC) is in the temperature range of 200-220 ° C;
(Iv) The crystallization enthalpy (ΔH) determined from the endothermic peak area in the temperature range of 200 to 220 ° C. by differential scanning calorimetry (DSC) is 2 to 15 J / g;
A thermoplastic polyurethane satisfying
This is a thermoplastic elastomer composition.
And this invention is a molded article which consists of an above-described thermoplastic elastomer composition.

Since the thermoplastic elastomer composition of the present invention is excellent in melt moldability, when molding such as extrusion molding using the thermoplastic elastomer composition of the present invention, the appearance does not occur without causing necking or cracking. And molded products such as films and sheets having excellent physical properties can be produced with high yield and high productivity.
Furthermore, since the thermoplastic elastomer composition of the present invention is free of sticking and has excellent anti-blocking properties, the thermoplastic elastomer composition of the present invention can be used without blending a large amount of lubricant and without using a release paper. Using the product, it is possible to smoothly produce a molded product such as a film or a sheet that can be easily wound and unwound.
The thermoplastic elastomer composition of the present invention and a molded product obtained using the same have excellent characteristics inherent in the ethylene-α-olefin copolymer, in particular, flexibility and elastic recovery, It has moderate strength, has little residual strain after elongation, and has an excellent function as a thermoplastic elastomer.
The thermoplastic elastomer composition of the present invention can be effectively used in a wide range of applications by taking advantage of the above-described excellent properties.

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

  When the proportion of units derived from ethylene in the ethylene-α-olefin copolymer (a) is less than 55 mol%, the softening point of the ethylene-α-olefin copolymer is lowered, and the thermoplastic polyurethane (b) It tends to be difficult to mix uniformly, and it tends to cause necking, cracks, and poor appearance when producing films and sheets from thermoplastic elastomer compositions, resulting in blocking in the resulting molded product. It becomes easy. On the other hand, when the ratio of the unit derived from ethylene in the ethylene-α-olefin copolymer (a) exceeds 99 mol%, it is difficult to obtain a film having a thin thickness and excellent stretchability.

In the copolymer of ethylene and an α-olefin having 4 or more carbon atoms, preferably used as the ethylene-α-olefin copolymer (a) in the thermoplastic elastomer composition of the present invention, the α-olefin having 4 or more carbon atoms is used. Examples of the unit (II) derived from olefin include 1-butene, 2-methyl-1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-hexene, Units derived from α-olefins such as octene, 1-decene, 1-octadecene and the like can be mentioned, and these α-olefin units (II) may be contained alone or in combination of two or more. Also good. Among them, the unit (II) is preferably a unit derived from an α-olefin having 4 to 12 carbon atoms, more preferably a unit derived from an α-olefin having 7 to 10 carbon atoms, More preferably, it is 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 an ethylene-α-olefin copolymer is converted into a thermoplastic polyurethane (b ) And a molded product obtained therefrom are likely to have low flexibility and elastic recovery after elongation.

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

The ethylene-α-olefin copolymer (a) preferably has a melt index measured at 190 ° C. under a load of 2.16 kg within a range of 0.1 to 12 g / 10 min, and is 0.2 to 7 g / More preferably within the range of 10 minutes, still more preferably within the range of 0.4 to 5 g / 10 minutes. 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 thin film. It is easy to manufacture. On the other hand, when the melt index of the ethylene-α-olefin copolymer (a) exceeds 12 g / 10 minutes, the thermoplastic elastomer composition and the molded product obtained therefrom are likely to be blocked, and the mechanical properties are lowered. easy.
In addition, the melt index of the ethylene-α-olefin copolymer referred to in the present specification is a value measured according to ASTM D-1238.

The 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. If the Shore A hardness of the ethylene-α-olefin copolymer (a) is less than 30, the mechanical properties of the molded product obtained from the thermoplastic elastomer composition containing it tend to be lowered. On the other hand, when the Shore A hardness of the ethylene-α-olefin copolymer (a) exceeds 90, the thermoplastic elastomer composition containing the copolymer and the molded product obtained therefrom tend to have insufficient flexibility.
In addition, Shore A hardness as used in this specification is the value measured based on ASTM D-2240.

Ethylene -α- olefin copolymer (a), it is preferable that its density is in the range of 0.85~0.93g / cm ^3, is in the range of 0.86~0.91g / cm ³ More preferably, it is still more preferably in the range of 0.86 to 0.90 g / cm ³ . By using the ethylene-α-olefin copolymer (a) having the above-described density, the thermoplastic elastomer composition of the present invention has melt moldability, blocking resistance, flexibility, and elastic recovery (low residual strain). Even better.
In addition, the density as used in this specification is the value measured based on ASTM D-792.

The ethylene-α-olefin copolymer (a) preferably has a Mooney viscosity measured at 100 ° C. using an L-shaped rotor in the range of ₅ to 70 ML _{1 + 4} (100 ° C.), 10 to 55 ML. More preferably, it is in the range of _{1 + 4} (100 ° C.). By using the ethylene-α-olefin copolymer (a) having the Mooney viscosity described above, the melt-moldability, blocking resistance, flexibility, elastic recovery (low residual strain property) of the thermoplastic elastomer composition of the present invention. ) Is even better.
In addition, the Mooney viscosity as used in this specification is the value measured based on ASTM D-1646.

  The manufacturing method in particular of ethylene-alpha-olefin copolymer (a) is not restrict | limited, It can manufacture by a conventionally well-known method. For example, ethylene and the above-mentioned α-olefin are subjected to a known method such as a solution polymerization method, a bulk polymerization method, and a gas phase polymerization method, usually at a temperature of 0 to 250 ° C. and a pressure of normal pressure to 1000 atmospheres (100 MPa). It can be obtained by polymerizing under. 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 excellent uniformity can be easily obtained. Can do. 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 cocatalyst such as methylaminooxane and a non-coordinating boron compound is used in an amount of 2 to 1 with respect to 1 mol of the metallocene compound. 1,000,000 moles, preferably 50 to 5,000 moles.

As described above, the thermoplastic polyurethane (b) used in the thermoplastic elastomer composition of the present invention has the following requirements (i) to (iv);
(I) a thermoplastic polyurethane obtained by reaction of a polyester diol having a number average molecular weight of 1,500 to 5,000, an organic diisocyanate and a chain extender;
(Ii) the nitrogen atom content is 2.6% by weight or more;
(Iii) the endothermic peak by differential scanning calorimetry (DSC) is in the temperature range of 200-220 ° C;
(Iv) The crystallization enthalpy (ΔH) determined from the endothermic peak area in the temperature range of 200 to 220 ° C. by differential scanning calorimetry (DSC) is 2 to 15 J / g;
Is satisfied.

That is, first, the thermoplastic polyurethane (b) used in the present invention 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 [requirement ( i)].
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 lowered, and the sticking is likely to occur. On the other hand, when the number average molecular weight of the polyester diol exceeds 5,000, the fluidity of the thermoplastic polyurethane is lowered, resulting in poor dispersibility in the ethylene-α-olefin copolymer (a). The melt moldability of the thermoplastic elastomer composition becomes poor. The polyester diol used in the production of 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 as used in this specification is a number average molecular weight calculated based on the hydroxyl value measured based on JIS K-1557.

  When a thermoplastic polyurethane obtained using a polymer diol other than polyester diol as the thermoplastic polyurethane, for example, a thermoplastic polyurethane obtained using other polymer diol such as polyether diol or polycarbonate diol, Even if the number average molecular weight of the other polymer diol is in the range of 1,500 to 5,000, the affinity between the thermoplastic polyurethane and the ethylene-α-olefin copolymer (a) decreases. The desired thermoplastic elastomer composition having excellent properties such as necking resistance, crack resistance, blocking resistance, and elastic recovery after elongation cannot be obtained.

The polyester diol used in the production of the thermoplastic polyurethane (b) may be obtained by, for example, subjecting a dicarboxylic acid component such as an ester-forming derivative such as a dicarboxylic acid, its ester, and an anhydride to a diol component directly according to a conventional method, or It can be produced by transesterification.
The polyester diol can also be produced by ring-opening polymerization of a lactone.

As the dicarboxylic acid component which is a production raw material of the polyester diol used for the production of the thermoplastic polyurethane (b), those generally used in the production of the polyester diol can be used. For example, succinic acid, glutaric acid, Adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, methylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, trimethyladipic acid, 2-methyloctanedioic acid, 3,8-dimethyl Aliphatic dicarboxylic acids having 4 to 12 carbon atoms such as decanedioic acid and 3,7-dimethyldecanedioic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc. Aromatic dicarboxylic acids; their ester-forming derivatives It is possible. The polyester diol can be formed using one or more of the dicarboxylic acid components described above.
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 that is a raw material for producing the polyester diol used for the production of the thermoplastic polyurethane (b), those generally used in the production of the polyester diol can be used. Specific examples include 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-butane Diol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 2 , 7-dimethyl-1,8-octanediol, 1,9- 2 carbon atoms such as nandiol, 2-methyl-1,9-nonanediol, 2,8-dimethyl-1,9-nonanediol, 1,10-decanediol, 2,2-diethyl-1,3-propanediol Aliphatic diols such as 1,4-cyclohexanediol, cyclohexanedimethanol, cyclooctanedimethanol and dimethylcyclooctanedimethanol; Fragrances such as 1,4-bis (β-hydroxyethoxy) benzene Group dihydric alcohol. These diols may be used alone or in combination of two or more. Among these, 2-methyl-1,4-butanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 2-methyl-1,9-nonanediol, 2, One or more of aliphatic diols having 5 to 12 carbon atoms having a methyl group as a side chain, such as 7-dimethyl-1,8-octanediol and 2,8-dimethyl-1,9-nonanediol, are used. It is preferable. In particular, the aliphatic diol having 5 to 12 carbon atoms having a methyl group as a side chain is more preferably used in a proportion of 30 mol% or more, based on the total amount of diol components forming the polyester diol, and 50 mol%. More preferably, it is used in the above ratio.

  In producing the polyester diol using the above-described dicarboxylic acid component and 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 completion of the polycondensation reaction, so that a thermoplastic elastomer composition having excellent properties such as melt moldability and crack resistance can be obtained. It is preferable from the point obtained.

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

  Examples of the method of deactivating the titanium-based polycondensation catalyst contained in the produced polyester diol include a method of deactivating the polyester diol obtained by the esterification reaction by bringing it into contact with water under heating. Examples thereof include a method of treating with a phosphorus compound such as acid, phosphoric acid ester, phosphorous acid, or phosphorous acid ester. When the titanium-based polycondensation catalyst is deactivated by contact with water, 1% by weight or more of water is added to the polyester diol obtained by the esterification reaction, and the temperature is 70 to 150 ° C, preferably 90 to 130 ° C. Heat 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.

  Examples of the lactone that can be used as a raw material for producing the polyester diol used in the production of the thermoplastic polyurethane (b) include ε-caprolactone and β-methyl-δ-valerolactone. 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, trimethylolbutane, pentane may be used as necessary within the range not impairing the object of the present invention. A small amount of a polyol such as erythritol, a tri- or higher functional polycarboxylic acid or an ester-forming derivative thereof may be used.

The type of the organic diisocyanate used in the production of the thermoplastic polyurethane (b) is not particularly limited, and any of aliphatic diisocyanate, alicyclic diisocyanate and aromatic diisocyanate conventionally used in the production of thermoplastic polyurethane is used. For example, a fragrance such as 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3′-dichloro-4,4′-diphenylmethane diisocyanate, etc. Diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate Nate etc. can be mentioned. These organic diisocyanates may be used alone or in combination of two or more.
Among these, 4,4′-diphenylmethane diisocyanate is preferably used.

There is no restriction | limiting in particular as chain extender used for manufacture of a thermoplastic polyurethane (b), Any of the chain extenders conventionally used for manufacture of thermoplastic polyurethane may be used, Among these, an isocyanate group and A low molecular compound having two active hydrogen atoms capable of reacting in the 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. Diols such as bis (β-hydroxyethyl) terephthalate and xylylene glycol; hydrazine, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine and derivatives thereof, phenylenediamine, tolylenediamine, adipic acid dihydrazide, isophthalic acid Examples include diamines such as dihydrazide; 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 these, aliphatic diols having 2 to 10 carbon atoms are preferably used, and 1,4-butanediol is more preferably used.

  In the production of the thermoplastic polyurethane (b), the ratio of [total number of moles of active hydrogen atoms possessed by polyester diol and chain extender]: [number of moles of isocyanate group based on organic diisocyanate] is 1: 0. It is preferable to carry out the reaction using the above-described polyester diol, organic diisocyanate and chain extender in such an amount as to be in the range of .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 above-described polyester diol, organic diisocyanate, and chain extender are used in the absence or presence of a solvent using a known urethanization reaction technique. Further, it may be produced by either the prepolymer method or the one-shot method.
Among these, a method of producing a thermoplastic polyurethane (b) by performing melt polymerization in a substantially solvent-free state 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.

The thermoplastic polyurethane (b) used in the present invention must satisfy the requirement (ii) that “the nitrogen atom content is 2.6% by weight or more” in addition to the requirement (i) described above. When the nitrogen content of the thermoplastic polyurethane is less than 2.6% by weight, the resistance of the thermoplastic elastomer composition obtained by blending such a thermoplastic polyurethane with the ethylene-α-olefin copolymer (a). The blocking property is inferior. The thermoplastic polyurethane (b) preferably has a nitrogen atom content of 2.6 to 6.0% by weight, more preferably 2.8 to 5.0% by weight. More preferably, it is in the range of 3.0 to 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 elemental analysis of the thermoplastic polyurethane.
The thermoplastic polyurethane (b) having a nitrogen atom content of 2.6% by weight or more is prepared by adjusting the molecular weight of the polyester diol, the organic diisocyanate and the chain extender, which are raw materials for producing the thermoplastic polyurethane (b), the organic diisocyanate and the chain. It can be obtained by adjusting the type and amount of the extender.

Further, the thermoplastic polyurethane (b) used in the present invention has an endothermic peak by differential scanning calorimetry (DSC) within a temperature range of 200 to 220 ° C. [Requirement (iii)], and differential scanning calorimetry (DSC It is necessary that the crystallization enthalpy (ΔH) determined from the endothermic peak area in the temperature range of 200 to 220 ° C. in the range of 2 to 15 J / g [requirement (iv)].
A thermoplastic elastomer composition obtained by blending such a thermoplastic polyurethane when the endothermic peak of the thermoplastic polyurethane is less than 200 ° C. and / or the crystallization enthalpy (ΔH) is less than 2 J / g. In products, melt moldability and blocking resistance are poor. On the other hand, when the endothermic peak of thermoplastic polyurethane exceeds 220 ° C. and / or the crystallization enthalpy (ΔH) exceeds 15 J / g, a thermoplastic elastomer composition obtained by blending such thermoplastic polyurethane When melted, an unmelted product is likely to be generated, and the molded product such as a film or a sheet obtained from the product has a flaw (fish eye), and the surface smoothness is lost. Etc., and the blocking resistance decreases.

The thermoplastic polyurethane (b) used in the present invention has an endothermic peak by differential scanning calorimetry (DSC) in the temperature range of 200 to 220 ° C. and a temperature range of 200 to 220 ° C. by differential scanning calorimetry (DSC). It is more preferable that the crystallization enthalpy (ΔH) determined from the endothermic peak area within the range of 3 to 10 J / g.
In addition, the specific measurement method of the temperature of the endothermic peak by differential scanning calorimetry (DSC) in this specification and the method of obtaining the crystallization enthalpy (ΔH) are as described in the section of the following examples.
The thermoplastic polyurethane (b) satisfying the requirements (iii) and (iv) is not limited, but examples thereof include polyester diol, organic diisocyanate and chain extender which are raw materials for producing the thermoplastic polyurethane (b). By adjusting the molecular weight of the organic diisocyanate and the type and amount of the organic diisocyanate and chain extender.

  Further, the viscosity of the thermoplastic polyurethane (b) may vary depending on the type of polyester diol, organic diisocyanate and chain extender used in the production thereof, and the nitrogen atom content in the thermoplastic polyurethane (b). Includes a solution having a concentration of 0.5 g / dl obtained by dissolving thermoplastic polyurethane (b) in N, N-dimethylformamide at 30 ° C., and its logarithmic viscosity is 0.2 to 1.2 dl. / G is preferable, 0.3 to 1.1 dl / g is more preferable, and 0.5 to 1.1 dl / g is more preferable. By using the thermoplastic polyurethane (b) having the logarithmic viscosity described above, the melt moldability and blocking resistance of the thermoplastic elastomer composition of the present invention are further improved.

  The thermoplastic elastomer composition of the present invention comprises an ethylene-α-olefin copolymer (a) and a thermoplastic polyurethane (b) satisfying the above requirements (i) to (iv). It is necessary that the α-olefin copolymer (a): thermoplastic polyurethane (b) is contained so that the weight ratio falls within the range of 70:30 to 90:10, and 75:25 to 85. : It is preferable to contain within the range of 15.

The content of the ethylene-α-olefin copolymer (a) is less than 70% by weight based on the total weight of the ethylene-α-olefin copolymer (a) and the thermoplastic polyurethane (b) [Thermoplastic polyurethane In the case of a thermoplastic elastomer composition such that the content of (b) exceeds 30% by weight, a molded product such as a film having a thin surface and a good surface state cannot be obtained, and the blocking resistance is high. It will be inferior.
On the other hand, based on the total weight of the ethylene-α-olefin copolymer (a) and the thermoplastic polyurethane (b), the content of the ethylene-α-olefin copolymer (a) exceeds 90% by weight [thermoplastic In the case of a thermoplastic elastomer composition such that the content of polyurethane (b) is less than 10% by weight, a necking phenomenon occurs when extrusion molding into a film or sheet using a T-die extruder or the like. As a result, the width of the film or sheet becomes narrower, and as a result, the range of thickness spots generated on both ends of the film or sheet becomes wider, and the width of the product obtained by trimming the thick part becomes extremely narrow, yield. Cause a significant decrease in Moreover, the blocking resistance of the thermoplastic elastomer composition or the molded product is inferior.

The thermoplastic elastomer composition of the present invention comprises an ethylene-α-olefin copolymer (a) and a thermoplastic polyurethane (b) satisfying the above requirements (i) to (iv). As long as the thermoplastic elastomer composition is contained so that the weight ratio of the polymer (a): the thermoplastic polyurethane (b) is in the range of 70:30 to 90:10 as described above, Other thermoplastic polymers may be contained in a small amount, preferably 10% by weight or less based on the total weight of the ethylene-α-olefin copolymer (a) and the thermoplastic polyurethane (b).
Such other thermoplastic polymers include, for example, thermoplastic polyurethanes that do not satisfy one or more of the above requirements (i) to (iv) [i.e., thermoplastic polyurethane (b And other thermoplastic polyurethanes], and polyolefins such as polyethylene and polypropylene.

In addition, the thermoplastic elastomer composition of the present invention is within a range that does not impair the effects of the present invention, and if necessary, a reinforcing agent, a colorant, a lubricant, an adhesive, a flame retardant, a weather resistance improver, an ultraviolet absorber, Various additives such as antioxidants, hydrolysis resistance improvers, fungicides, antibacterial agents and stabilizers; various fibers such as glass fibers and polyester fibers; inorganic substances such as talc and silica; arbitrary coupling agents and the like The component may be contained.
These components are added after the production process or production of the ethylene-α-olefin copolymer (a), after the production process or production of the thermoplastic polyurethane (b), and / or during the preparation of the thermoplastic elastomer composition. Can do.

The method for preparing the thermoplastic elastomer composition of the present invention is not particularly limited, and any method conventionally employed in preparing the thermoplastic polymer composition may be used. For example, an ethylene-α-olefin copolymer (a), a thermoplastic polyurethane (b), and others as required are used by using a vertical or horizontal mixer as is usually used for mixing resin materials. After pre-mixing the thermoplastic polymer and other components in a specified ratio, using a single or twin screw extruder, mixing roll, Banbury mixer, etc., melt and knead under heating in batch or continuous mode By doing so, the thermoplastic elastomer composition of the present invention can be obtained. In this case, the melt kneading temperature may vary depending on the type of ethylene-α-olefin copolymer (a) and thermoplastic polyurethane (b) to be 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, other thermoplastic polymer and other components are blended in the latter stage of polymerization when the thermoplastic polyurethane (b) is produced. Thus, a thermoplastic elastomer composition may be prepared.

The thermoplastic elastomer composition of the present invention can be melt-molded and heat-processed, and various molding methods generally employed for thermoplastic polymers, such as extrusion molding, injection molding, blow molding, and calendering. Various molded products such as films, sheets, plates, tubes, rods, various block molded products, hollow molded products, tray molded products, fibers, etc. by molding, press molding, vacuum molding, injection molding, melt spinning, etc. And products can be manufactured smoothly.
Although not limited, for example, in the case of molding or spinning technology involving melting such as extrusion molding, injection molding, blow molding, melt spinning, etc., 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 a film or sheet is produced using a T-die type extrusion molding machine, necking in the extruded film or sheet is greatly increased. As a result, the ratio of the thickness spots at both ends of the film or sheet is reduced, so that the width of the product obtained by trimming the both ends with the thickness spots is large. Products such as films and sheets can be manufactured with high yield and high productivity. In addition, molded articles such as films and sheets obtained thereby have excellent anti-blocking properties without sticking, do not stick to each other even when wound as they are, can be easily rewound later, and are expensive. There is no need to use a pattern and no need to use a large amount of lubricant that may ooze out.
In addition, films, sheets, and other molded articles obtained using the thermoplastic elastomer composition of the present invention have a smooth and good surface state, and are excellent in flexibility, stretchability, elastic recovery, and after elongation. The residual strain is small, has excellent mechanical properties such as tensile breaking strength and tensile breaking elongation, and has an appropriate strength.

Therefore, molded articles obtained from the thermoplastic elastomer composition of the present invention, particularly sheets and films, are made of stretchable films (such as sanitary napkins, disposable diapers, sealing materials, dustproof materials, etc.) by taking advantage of the above-described excellent properties. It can be used effectively for purposes such as a sheet.
Furthermore, the thermoplastic elastomer composition of the present invention is not limited to the above-described applications, and can be effectively used for applications such as various conveyor belts, keyboard sheets, and various containers.
The thermoplastic elastomer composition of the present invention is also suitable for the production of laminates with nonwoven fabrics and other fibrous base materials, and laminates with other polymer films and sheets, and the like. The laminate can be easily obtained by, for example, melt-extruding the thermoplastic elastomer composition of the present invention in the form of a film or sheet on a fibrous base material or other base material.

Hereinafter, the present invention will be specifically described with reference to Examples and the like, but the present invention is not limited 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 endotherm in the temperature range of 200 to 220 ° C. by differential scanning calorimetry (DSC) Crystallization enthalpy (ΔH) determined from peak area, melt moldability of thermoplastic elastomer composition, state of film during extrusion (easiness of winding), film appearance, blocking resistance, 100% modulus (M100 ) And residual strain were measured or evaluated by the following methods.

(1) Nitrogen atom content of thermoplastic polyurethane:
Using an elemental analyzer ("240-2 type" manufactured by PerkinElmer Co., Ltd.), elemental analysis of the thermoplastic polyurethane was performed 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 was prepared by dissolving thermoplastic polyurethane in N, N-dimethylformamide, and the above-prepared thermoplastic polyurethane solution was allowed to flow down at 30 ° C. using an Ubbelohde viscometer. The time was measured and the logarithmic viscosity of the thermoplastic polyurethane was determined by the following mathematical formula.

Logarithmic viscosity of thermoplastic polyurethane (dl / g) = {ln (t / t ₀ )} / c

[Wherein t is the flow time (seconds) of the thermoplastic polyurethane solution, t ₀ is the flow time (seconds) of the solvent (N, N-dimethylformamide), and c is the concentration of the thermoplastic polyurethane (0.5 g / dl). Indicates. ]

(3) Endothermic peak temperature and crystallization enthalpy (ΔH) by differential scanning calorimetry (DSC) of thermoplastic polyurethane:
(3-1) Using a differential scanning calorimeter (“DSC30” manufactured by Mettler), about 10 mg of thermoplastic polyurethane is heated at a temperature rising rate of 10 ° C./min in a nitrogen gas atmosphere and melted. The enthalpy was measured to determine the endothermic peak (° C.).
(3-2) In the measurement of the melting enthalpy of the thermoplastic polyurethane in (3-1) above, the crystallization enthalpy (ΔH) (J / g) was determined from the endothermic peak area in the temperature range of 200 to 220 ° C.

(4) Melt moldability of thermoplastic elastomer composition (thermoplastic elastomer):
Using the thermoplastic elastomer compositions (thermoplastic elastomers) of the following examples and comparative examples, using a T-die type single screw extruder (25 mmφ; effective width of die 350 mm, lip gap 0.3 mm), Extrusion is performed under the conditions described in the following Examples and Comparative Examples to produce a film, and the film width (W ₂ ) (mm) 10 cm downstream from the T-die outlet is measured, and the effective width of the T-die (W ₁ ) From the relationship with (mm), the necking rate (%) of the extruded film was calculated by the following formula and used as an index of melt moldability.

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

(5) State of film during extrusion molding (ease of winding):
After the film-like material extruded from the T-die extruder is brought into contact with a cooling roll having a surface temperature of 30 ° C. and cooled, the film is wound at a winding speed of about 3 m / min without using a release paper. did.
During winding, the state of the film was visually observed and evaluated according to the criteria shown in Table 1 below.

(6) Appearance of film:
In the above (5), in the case of a film wound up or a film that cannot be wound up, the surface state of the film immediately before the winder is visually observed, and a smooth surface is good (◯). Those having irregularities on the surface due to poor dispersion between them were evaluated as defective (x).

(7) Blocking resistance of the film:
After the film-like material extruded from the T-die extruder is brought into contact with a cooling roll having a surface temperature of 30 ° C. and cooled, the film is wound at a winding speed of about 3 m / min without using a release paper. did. The wound film was allowed to stand at room temperature for 24 hours, and then rewound by hand. Based on the resistance at that time, the blocking resistance was evaluated according to the criteria shown in Table 2 below.

(8) 100% modulus of film (M100):
A test piece (length × width = 20 cm × 5 cm) was taken from a 30 μm-thick film manufactured using a T-die type extrusion molding machine, and an autograph measurement device (“IS” manufactured by Shimadzu Corporation) was used. -500D "), the modulus (M100) (kgf / cm ² ) when stretched at a tensile rate of 300 mm / min at room temperature and stretched by 100% was measured.

(9) Residual distortion of film:
A test piece (length × width = 20 cm × 5 cm) was taken from a 30 μm-thick film manufactured using a T-die type extrusion molding machine, and an autograph measurement device (“IS” manufactured by Shimadzu Corporation) was used. -500D ") at room temperature at a pulling speed of 300 mm / min to 100% extension, then at a speed of 300 mm / min back to the pre-extension position (first cycle) and then again at the same speed to 100 again % Stretch, and then return to the position before stretching at the same speed (second cycle). The length of the test piece at this point (second cycle) was measured, and the residual strain (%) of the film was calculated from the following formula. Asked.

Residual strain of film (%) = {(L ₂ −L ₁ ) / L ₁ } × 100
[In the formula, the length of the test piece before L ₁ is extending (20 cm), L ₂ is the length of the second cycle after the end of the test piece (cm). ]

Abbreviations for the polymers used in the following Examples and Comparative Examples and their contents are as shown below.
[Ethylene-α-olefin copolymer (a)]
・ POE-A:
Ethylene-1-octene copolymer [“ENGAGE EG8100” manufactured by DuPont Dow Elastomer Co., Ltd., ethylene unit / 1-octene unit molar ratio = 92.7 / 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:
Ethylene-1-octene copolymer [“ENGAGE EG8150” manufactured by DuPont Dow Elastomer Co., Ltd., ethylene unit / 1-octene unit molar ratio = 92.5 / 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:
Thermoplastic polyurethane obtained by reaction of polyester diol (number average molecular weight = 3,500) / 4,4′-diphenylmethane diisocyanate / 1,4-butanediol comprising 3-methyl-1,5-pentanediol and adipic acid [ Nitrogen atom content = 3.2 wt%, 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:
A mixture of 1,4-butanediol and 1,6-hexanediol (molar ratio = 60: 40) and polyester diol composed of adipic acid (number average molecular weight = 2,000) / 4,4′-diphenylmethane diisocyanate / 1, Thermoplastic polyurethane obtained by reaction of 4-butanediol [nitrogen atom content = 3.1 wt%, endothermic peak temperature by differential scanning calorimetry (DSC) = 206 ° C., crystallization enthalpy (ΔH) = 5.3 J / g, logarithmic viscosity = 1.01 dl / g].

・ TPU-C:
Thermoplastic polyurethane obtained by reaction of polyester diol (number average molecular weight = 3,500) / 4,4′-diphenylmethane diisocyanate / 1,4-butanediol comprising 3-methyl-1,5-pentanediol and adipic acid [ Nitrogen content = 2.4 wt%, endothermic peak temperature by differential scanning calorimetry (DSC) = 171 ° C., crystallization enthalpy (ΔH) = 8.8 J / g, logarithmic viscosity = 1.38 dl / g].
・ TPU-D:
Polyester diol composed of 1,4-butanediol and adipic acid (number average molecular weight = 1,000) / 4,4′-diphenylmethane diisocyanate / 1,4-butanediol thermoplastic polyurethane [nitrogen atom content = 4.4 wt%, endothermic peak temperature by differential scanning calorimetry (DSC) = 175 ° C., crystallization enthalpy (ΔH) = 0 J / g, logarithmic viscosity = 0.90 dl / g].
・ TPU-E:
Polyester diol (number average molecular weight = 2,000) / 4,4′-diphenylmethane composed of a mixture of 1,9-nonanediol and 2-methyl-1,8-octanediol (molar ratio = 65: 35) and adipic acid Thermoplastic polyurethane obtained by reaction of diisocyanate / 1,4-butanediol [nitrogen atom content = 4.3 wt%, 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, after POE-A and TPU-A were premixed at a ratio of 80 parts by weight: 20 parts by weight, the mixture was supplied to a single screw extruder and melted at 200 ° C. The mixture was kneaded, extruded into strands, and cut to produce thermoplastic elastomer composition pellets.
(2) The pellets of the thermoplastic elastomer composition obtained in (1) above are supplied to a uniaxial T-die extruder (25 mmφ, cylinder temperature 180-200 ° C., die temperature 200 ° C.) and melt-kneaded. Then, the film was extruded from the T die into a film shape, brought into contact 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 a release paper to produce a film. .
(3) Melt moldability of the thermoplastic elastomer composition at the time of extrusion molding in the above (2), film state (easiness of winding), appearance of the obtained film, blocking resistance, 100% modulus (M100) When the residual strain was measured or evaluated by the method described above, it was as shown in Table 3 below.

<< Examples 2 to 5 >>
(1) After premixing the ethylene-α-olefin copolymer (a) and thermoplastic polyurethane shown in Table 3 below in the proportions shown in Table 3, the mixture is supplied to a single screw extruder at 200 ° C. The mixture was melt-kneaded, extruded into strands, and cut to produce thermoplastic elastomer composition pellets.
(2) Using the thermoplastic elastomer composition pellets 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 extrusion molding in the above (2), film state (easiness of winding), appearance of the obtained film, blocking resistance, 100% modulus (M100) When the residual strain was measured or evaluated by the method described above, it was as shown in Table 3 below.

<< Comparative Examples 1-6 >>
(1) The ethylene-α-olefin copolymer (a) and thermoplastic polyurethane shown in Table 3 below are premixed at the ratio shown in Table 3, and then supplied to a single screw extruder and melt-kneaded at 200 ° C. The pellets were extruded into strands and cut to produce thermoplastic elastomer composition pellets (Comparative Examples 1 to 5) (Comparative Example 6 uses only POE-A).
(2) A pellet of the thermoplastic elastomer composition obtained in (1) (Comparative Examples 1 to 5) or an ethylene-α-olefin copolymer (POE-A) (Comparative Example 6) After supplying to a T-die type extrusion molding machine (25 mmφ, cylinder temperature 180-200 ° C., die temperature 200 ° C.) and melt-kneading, it is extruded from the T-die into a film shape and brought into contact with a cooling roll having a surface temperature of 30 ° C. After cooling, the film was produced by winding at a winding speed of about 3 m / min without using a release paper.
(3) Melt moldability of the thermoplastic elastomer composition at the time of extrusion molding in the above (2), film state (easiness of winding), appearance of the obtained film, blocking resistance, 100% modulus (M100) When the residual strain was measured or evaluated by the method described above, it was as shown in Table 3 below.

From the results of Table 3 above, the thermoplastic elastomer compositions of Examples 1 to 5, that is, the ethylene-α-olefin copolymer (a) and the thermoplastic polyurethane satisfying the above requirements (i) to (iv) (B) The thermoplastic elastomer composition containing (TPU-A or TPU-B) in a weight ratio of 70:30 to 90:10 defined in the present invention has a low necking rate during film extrusion. It can be seen that the film is excellent in melt moldability and is excellent in the film state (easiness of winding) during extrusion molding. Moreover, the films obtained in Examples 1 to 5 have a smooth surface and excellent appearance, no sticking and excellent blocking resistance, and can be smoothly wound and rewound, and 100%. It can be seen that the value of the modulus (M100) is in an appropriate range and has an appropriate flexibility, and that the elasticity is excellent and the residual strain is small even after elongation.
And the result of Example 5 is the weight of 70: 30-90: 10 for the thermoplastic polyurethane (b) which satisfies the requirements (i)-(iv) of said ethylene-alpha-olefin copolymer (a). In the thermoplastic elastomer composition of the present invention contained in a ratio, even if some thermoplastic polyurethane other than the thermoplastic polyurethane (b) (TPU-C in Example 5) is contained, the excellent properties are impaired. It shows no.

  On the other hand, the above-described requirements for the thermoplastic elastomer compositions of Comparative Examples 1 to 5 and the polymer of Comparative Example 6, that is, the ethylene-α-olefin copolymer (a), which do not satisfy the various requirements in the present invention ( i) Thermoplastic elastomer composition of Comparative Examples 1 to 3, wherein only the thermoplastic polyurethane (TPU-C, TPU-D, TPU-E) not satisfying any of (iv) is blended, ethylene-α- Even if the thermoplastic polyurethane (TPU-A, TPU-B) satisfying the above requirements (i) to (iv) is blended with the olefin copolymer (a), the blending amount is defined by the present invention. Comparative examples comprising the thermoplastic elastomer compositions of Comparative Example 4 and Comparative Example 5 and the ethylene-α-olefin copolymer (a) alone, which are out of the weight ratio range of 70:30 to 90:10. No. 6, the necking rate at the time of extrusion molding of the film is large and inferior in melt moldability, the film state at the time of extrusion molding (ease of winding) is inferior, or the resulting film has irregularities on the surface and the appearance , Is it hard to stick and has poor blocking resistance and is difficult or impossible to unwind, or is the value of 100% modulus (M100) inadequate and does not have adequate flexibility? And / or it is inferior in elastic recoverability, and it turns out that the residual distortion after expansion | extension is large.

The thermoplastic elastomer composition of the present invention is excellent in melt moldability, free from sticking and excellent in blocking resistance, and therefore excellent in appearance and physical properties without causing necking or cracking by molding such as extrusion molding. Further, it is possible to produce a molded product such as a film or a sheet that can be easily wound and unwound with high yield and high productivity.
Moreover, 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, in particular, flexibility and elastic recovery, Since it has an appropriate strength, has a small residual strain after elongation, and has an excellent function as a thermoplastic elastomer, it can be effectively used in a wide range of applications by taking advantage of these excellent properties.

Claims (4)

(1) An ethylene-α-olefin copolymer (a) and a thermoplastic polyurethane (b) are converted into an ethylene-α-olefin copolymer (a): a thermoplastic polyurethane (b) = 70:30 to 90:10. A thermoplastic elastomer composition containing by weight; and (2) the thermoplastic polyurethane (b) comprises the following requirements (i) to (iv):
(I) a thermoplastic polyurethane obtained by reaction of a polyester diol having a number average molecular weight of 1,500 to 5,000, an organic diisocyanate and a chain extender;
(Ii) the nitrogen atom content is 2.6% by weight or more;
(Iii) the endothermic peak by differential scanning calorimetry (DSC) is in the temperature range of 200-220 ° C;
(Iv) The crystallization enthalpy (ΔH) determined from the endothermic peak area in the temperature range of 200 to 220 ° C. by differential scanning calorimetry (DSC) is 2 to 15 J / g;
A thermoplastic polyurethane satisfying
A thermoplastic elastomer composition characterized by the above.   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: derived from the α-olefin. The thermoplastic elastomer composition according to claim 1, wherein the molar ratio of the units is 55:45 to 99: 1.   A molded article comprising the thermoplastic elastomer composition according to claim 1.   The molded article according to claim 3, which is a film or a sheet.