JP2001064506A - Thermoplastic polyurethane composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compsn. excellent in elongation at a low stress and adhesiveness with a substrate, and having small residual strain and high recovery stress after elongation, by compounding thermoplastic polyurethanes each contg. a polymer polyol unit or a polyether polyol unit and having a specified nitrogen atom content and crystallization enthalpy. SOLUTION: This compsn. comprises 40-90 wt.% thermoplastic polyurethane comprising a polymer polyol unit having a number average mol.wt. of 500-8,000, an org. diisocyanate unit, and a chain extender and having not higher than 2.5 wt.% nitrogen atom content and less than 1 J/g crystallization enthalpy, and 60-10 wt.% thermoplastic polyurethane comprising a polyether polyol unit having a number average mol.wt. of 1,500-5,000, an org. diisocyanate unit, and a chain extender unit and having not lower than 1.5 wt.% nitrogen atom content and 1-15 J/g crystallization enthalpy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic polyurethane composition comprising a thermoplastic polyurethane having excellent flexibility and a thermoplastic polyurethane having excellent melt moldability, and a film and a sheet comprising the thermoplastic polyurethane composition. Related to other molded products. The thermoplastic polyurethane composition of the present invention is excellent in melt moldability, and in particular, is excellent in blocking resistance and extensibility at low stress by melt extrusion molding and inflation molding, and has high recovery stress after elongation and after elongation. Molded products such as films and sheets that not only have low residual strain but also have excellent adhesion to various substrates
It can be manufactured with high productivity.

[0002]

2. Description of the Related Art Thermoplastic polyurethane has mechanical performance,
Because of its excellent properties such as abrasion resistance, elastic recovery, oil resistance, and flexibility, it is attracting attention as a substitute for rubber and plastic. For example, films and sheets formed by extrusion of thermoplastic polyurethane have attracted attention as stretchable materials for disposable diapers. This elastic film for disposable diapers is intended to prevent the disposable diaper from coming off the body with a moderate force when the disposable diaper is attached, and to be thin and can be stretched with a small force. Instead, the stress (recovery stress) that tries to return to the original shape after elongation is high,
It is required to have the property of being excellent in dimensional stability (small residual strain). Therefore, in order to satisfy such a demand, a method of lowering the hardness of the thermoplastic polyurethane has been attempted, but in such a method,
When a molded product such as a film or a sheet is melt-extruded using a T-die extruder or the like, a phenomenon in which the width of the molded product extruded from the T-die becomes significantly narrower than the effective width of the T-die ( Hereinafter, this phenomenon will be referred to as “neck-in phenomenon”), and only a molded article having uneven thickness at both ends can be obtained. Therefore, in order to obtain a uniform molded article without uneven thickness, it is necessary to trim portions having uneven thickness at both ends of the molded article, and the productivity of the molded article deteriorates. Furthermore, since the obtained molded article has poor blocking resistance, when producing molded articles such as films and sheets, it is necessary to produce the molded articles using expensive release paper, for example, which is extremely troublesome and costly. There is a problem that it takes.

In recent years, a lubricant has been blended with a thermoplastic polyurethane using a high molecular weight diol having a specific number average molecular weight for the purpose of improving the melt extrudability of the thermoplastic polyurethane while maintaining the properties of the thermoplastic polyurethane. It has been proposed. For example, Japanese Patent Application Laid-Open No. 8-27376 discloses that a general high-hardness thermoplastic polyurethane composed of a polyetherdiol unit having a specific number average molecular weight, an organic diisocyanate unit and a chain extender unit is mixed with a lubricant. A plastic polyurethane composition is described.

[0004]

However, according to the study of the present inventors, it was found that simply blending a lubricant with a general thermoplastic polyurethane having a limited number average molecular weight of a high molecular polyol would result in a T-die type. It has been found that the neck-in phenomenon that occurs when melt-extruding a molded product such as a film or sheet using an extruder or the like is not sufficiently improved. Further, it has been found that when a molded article such as a film or a sheet is melt-molded from this thermoplastic polyurethane composition using an inflation molding machine, defective phenomena such as uneven thickness and cracks are likely to occur. In addition, since thermoplastic polyurethane has a strong tackiness and tends to cause blocking, when a film or sheet is produced by melt extrusion molding or the like, an amide compound is used for the purpose of detackification, prevention of blocking, and imparting releasability. It is generally known to add a lubricant such as. However, in molded articles such as thermoplastic polyurethane films and sheets obtained by adding this amide compound, the amide compound bleeds out on the surface of the molded article, causing many irregularities on the surface and loss of smoothness. Problem. Further, molded articles such as thermoplastic polyurethane films or sheets having an amide compound bleed out on the surface are laminated with a base made of nonwoven fabric or other fiber cloth, or a base made of another polymer film or sheet. However, there is a problem that the adhesive performance in the case of producing the polymer, specifically, the hot melt adhesive performance, etc. is remarkably reduced.

The inventors of the present invention have been studying to provide a thermoplastic polyurethane composition which is non-adhesive, excellent in blocking resistance, and excellent in release property, and has already disclosed in Japanese Patent Application Laid-Open No. 9-3321 a polyester-based composition. It has been found that it is important to use a thermoplastic polyurethane composition in which a polyester thermoplastic polyurethane having specific crystallinity is used in combination with the thermoplastic polyurethane. However, even with this thermoplastic polyurethane composition, it is practically desired to further improve the melt-extrusion moldability at a temperature in a normally used range. Therefore, an object of the present invention is to set T
-Improvements to eliminate neck-in phenomena that occur when melt-extrusion molding using a die-type extruder, and poor phenomena such as uneven thickness and cracks that occur when melt-molding with an inflation molding machine. Heat that can produce molded products such as films and sheets with excellent productivity, high recovery stress after elongation, low residual strain after elongation, and excellent adhesion to substrates with higher productivity than before An object of the present invention is to provide a plastic polyurethane composition. It is a further object of the present invention to provide a molded article such as a film or sheet made of the thermoplastic polyurethane composition.

[0006]

Means for Solving the Problems As a result of repeated studies by the present inventors to achieve the above object, the soft segment of the thermoplastic polyurethane (b) constituting the composition comprising two types of thermoplastic polyurethanes was obtained. Solubility parameter (SP
Value) is smaller than that of the polyester polyol, the difference between the SP value of the organic diisocyanate and the SP value of the hard segment composed of the chain extender becomes large, and the phase separation between the soft segment and the hard segment increases. It has been found that when the thermoplastic polyurethane (b) is used in combination with another thermoplastic polyurethane (a), the melt moldability and the blocking resistance of the thermoplastic polyurethane composition are further improved. Specifically, the neck-in phenomenon at the time of melt extrusion molding with a T-die type extruder or the like is remarkably improved, and the blocking resistance is also excellent,
It is possible to produce molded products such as films and sheets having very suitable mechanical performance as a stretchable material with good productivity, and even when melt-molded with an inflation molding machine, thickness unevenness and cracks are less likely to occur. A high quality molded product can be manufactured with high productivity.

That is, the present invention relates to a thermoplastic polyurethane composition comprising two types of thermoplastic polyurethanes (a) and (b); (i) the thermoplastic polyurethane (a) has a number average molecular weight of 500 to 500; It is composed of 8,000 polymer polyol units, organic diisocyanate units and chain extender units, has a nitrogen atom content of 2.5% by weight or less, and has an endothermic peak at 190 ° C. or more in differential scanning calorimetry (DSC). A thermoplastic polyurethane having a crystallization enthalpy (ΔH) of less than 1 J / g as determined from the endothermic peak; (ii) the thermoplastic polyurethane (b) has a number average molecular weight of 1,500 to 5,000. A polyether polyol unit, an organic diisocyanate unit and a chain extender unit, having a nitrogen atom content of 1.5% by weight or more, A thermoplastic polyurethane exhibiting an endothermic peak in the range of 190 to 230 ° C. by differential scanning calorimetry (DSC) and having an enthalpy of crystallization (ΔH) of 1 to 15 J / g determined from the endothermic peak; Based on the total weight of the types of thermoplastic polyurethanes (a) and (b), the thermoplastic polyurethane (a) is contained in a proportion of 40 to 90% by weight, and the thermoplastic polyurethane (b) is contained in a proportion of 60 to 10% by weight. A thermoplastic polyurethane composition. Then, based on the total weight of the two types of thermoplastic polyurethanes (a) and (b), a block copolymer comprising an aromatic vinyl compound polymer block and a conjugated diene polymer block, and the block copolymer At least one (c) of the hydrogenated product of
It is a thermoplastic polyurethane composition contained in a percentage by weight. Further, the present invention is a molded article such as a film or a sheet comprising the thermoplastic polyurethane composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic polyurethane (a) used in the present invention is composed of a polymer polyol unit, an organic diisocyanate unit and a chain extender unit. Further, the thermoplastic polyurethane (b) used in the present invention
Is composed of a polyether polyol unit, an organic diisocyanate unit and a chain extender unit. Examples of the polymer polyol constituting the thermoplastic polyurethane (a) include a polyester polyol, a polyether polyol, a polycarbonate polyol, and a polyester polycarbonate polyol. These polymer polyols may be used alone or in combination of two or more. Among these, it is preferable to use a polyester polyol or a polyether polyol, and it is more preferable to use a polyether polyol from the viewpoint of compatibility with the thermoplastic polyurethane (b).

The above polyester polyol is subjected to, for example, a direct esterification reaction or a transesterification reaction between the polyol and a dicarboxylic acid or an ester-forming derivative such as an ester or an anhydride thereof according to a conventional method, or starting the polyol or the like. It can be produced by ring-opening polymerization of lactone as an agent. As the polyol constituting the polyester polyol, those generally used in the production of polyester can be used. For example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 2- Methyl-1,3
-Propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 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-nonanediol, 2-methyl-1,9-nonanediol, 2,8-dimethyl-
Aliphatic diols having 2 to 15 carbon atoms such as 1,9-nonanediol and 1,10-decanediol; alicyclic rings such as 1,4-cyclohexanediol, cyclohexanedimethanol, cyclooctanedimethanol, dimethylcyclooctanedimethanol; Formula diols; diols having two hydroxyl groups per molecule, such as aromatic dihydric alcohols such as 1,4-bis (β-hydroxyethoxy) benzene, and the like. 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, 2,7-dimethyl-1,8-octanediol, 2-methyl-1,9-nonanediol, 2,8-dimethyl-1,9- It is preferable to use an aliphatic diol having 5 to 12 carbon atoms having a methyl group as a side chain such as nonanediol, and it is more preferable to use these aliphatic diols in a proportion of 30 mol% or more based on the total amount of the diol. More preferably, it is more preferably used in a proportion of 50 mol% or more. Furthermore, within a range that does not impair the spirit of the present invention, a small amount of a polyol having three or more hydroxyl groups per molecule can be used. For example, trimethylolpropane, trimethylolethane, glycerin,
Examples include 1,2,6-hexanetriol, pentaerythritol, diglycerin, methylglycoxide and the like.

As the dicarboxylic acid constituting the polyester polyol, those generally used in the production of polyester 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,
Aliphatic dicarboxylic acids having 4 to 12 carbon atoms such as 3,8-dimethyldecandioic acid and 3,7-dimethyldecandioic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid, orthophthalic acid; And aromatic dicarboxylic acids such as naphthalenedicarboxylic acid. These dicarboxylic acids may be used alone or in combination of two or more. Among these, it is preferable to use a fatty acid dicarboxylic acid having 6 to 12 carbon atoms, and it is more preferable to use adipic acid, azelaic acid, and sebacic acid. Examples of the lactone include ε-caprolactone and β-methyl-δ-valerolactone.

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, poly (methyltetramethylene ether) glycol, polytetramethylmethylene ether obtained by ring-opening polymerization of a cyclic ether in the presence of a polyol. Methylene ether triol and the like,
One or more of these can be used. Among these, it is preferable to use polytetramethylene ether glycol.

As the polycarbonate polyol, for example, those obtained by reacting a polyol with a carbonate compound such as dialkyl carbonate, alkylene carbonate, diaryl carbonate and the like can be used. As the polyol constituting the polycarbonate polyol, the polyol exemplified above as the constituent component of the polyester polyol can be used. Also, as the dialkyl carbonate, dimethyl carbonate,
Diethyl carbonate and the like. Further, the alkylene carbonate includes ethylene carbonate, and the diaryl carbonate includes diphenyl carbonate.

The polyester polycarbonate polyol is obtained, for example, by simultaneously reacting a polyol, a dicarboxylic acid and a carbonate compound. Alternatively, it can be obtained by previously synthesizing a polyester polyol and a polycarbonate polyol by the above-mentioned method, and then reacting them with a carbonate compound or with a polyol and a dicarboxylic acid. The number average molecular weight of the polymer polyol constituting the thermoplastic polyurethane (a) is from 500 to
8,000, preferably from 600 to 5,000, and more preferably from 800 to 5,000.
By using a polymer polyol having a number average molecular weight within this range, a thermoplastic polyurethane composition having more excellent mechanical performance and melt moldability can be obtained. In addition, the number average molecular weight of the polymer polyol referred to in the present invention is JIS
It is a number average molecular weight calculated based on the hydroxyl value measured according to K-1577.

Further, as the polyether polyol constituting the thermoplastic polyurethane (b), the polyether polyol exemplified above among the polymer polyols constituting the thermoplastic polyurethane (a) can be used.
The number average molecular weight of the polyether polyol constituting the thermoplastic polyurethane (b) is from 1,500 to 5,000, preferably from 1,800 to 4,000. By using a polyether polyol having a number average molecular weight within this range, a thermoplastic polyurethane composition having more excellent melt moldability and blocking resistance can be obtained. The number average molecular weight of the polyether polyol referred to in the present invention is a number average molecular weight calculated based on a hydroxyl value measured according to JIS K-1577. The SP value of the polyether polyol (corresponding to the soft segment) constituting the thermoplastic polyurethane (b) is 5 to 10
Is preferably, and more preferably 6 to 9.5. By using a polyether polyol having an SP value within this range, the SP value of the hard segment composed of the organic diisocyanate and the chain extender (about 1) can be obtained.
Since the difference of 2.5) is increased, the phase separation between the soft segment and the hard segment is increased, and a thermoplastic polyurethane composition having more excellent melt moldability and blocking resistance is obtained. The SP value of the polyether polyol referred to in the present invention is determined by the method of Fedors ("Basic Science of Coating", Yuji Harasaki [1977, 9, 15 First Edition] 5
(See page 5).

The organic diisocyanate used in the production of the two types of thermoplastic polyurethanes (a) and (b) is not particularly limited, and any of the organic diisocyanates conventionally used in the production of ordinary thermoplastic polyurethanes can be used. For example, for example, 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate,
Phenylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3 '
Aromatic diisocyanates such as -dichloro-4,4'-diphenylmethane diisocyanate; hexamethylene diisocyanate, isophorone diisocyanate,
Examples thereof include aliphatic or alicyclic diisocyanates such as 4′-dicyclohexylmethane diisocyanate and hydrogenated xylylene diisocyanate. These organic diisocyanates may be used alone or 2
More than one species may be used in combination. Among these, 4,4'-
It is preferred to use diphenylmethane diisocyanate.

The chain extender used in the production of the two types of thermoplastic polyurethanes (a) and (b) of the present invention is not particularly limited, and the chain extension conventionally used in the production of ordinary thermoplastic polyurethanes. Any of the agents may be used, and it is preferable to use a low molecular weight compound having a molecular weight of 300 or less and having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule. For example, ethylene glycol, propylene glycol, 1,4-butanediol,
1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol, bis (β-hydroxyethyl) terephthalate,
Diols such as xylylene glycol; hydrazine,
Diamines such as ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine and derivatives thereof, phenylenediamine, tolylenediamine, xylenediamine, adipic dihydrazide and isophthalic dihydrazide; amino alcohols such as aminoethyl alcohol and aminopropyl alcohol And the like. These low molecular compounds may be used alone or in combination of two or more. Among these, it is preferable to use an aliphatic diol having 2 to 10 carbon atoms, and it is more preferable to use 1,4-butanediol.

In producing the two types of thermoplastic polyurethanes (a) or (b) by reacting the above-mentioned polymer polyol or polyether polyol with an organic diisocyanate and a chain extender, the mixing ratio of each component is as follows:
It is appropriately determined in consideration of the hardness to be imparted to the target thermoplastic polyurethane, and is determined based on 1 mol of active hydrogen atoms of the polymer polyol or polyether polyol and the chain extender with respect to the organic diisocyanate. It is preferable to use each component in such a ratio that the isocyanate group contained in the above becomes 0.9 to 1.2 mol. The use of each component at the above ratio is preferable because a thermoplastic polyurethane composition having excellent melt moldability, blocking resistance, flexibility, elastic recovery, and the like can be obtained.

The method for producing the two types of thermoplastic polyurethanes (a) and (b) of the present invention is not particularly limited.
It may be produced by either a prepolymer method or a one-shot method using an organic diisocyanate and a chain extender. Among these, regarding the method for producing the thermoplastic polyurethane (b), the difference in SP value between the polyether polyol constituting the soft segment, the organic diisocyanate constituting the hard segment and the chain extender is large, and the compatibility is high. Because of poor properties, a melt polymerization method capable of rapidly stirring and mixing at a high shear rate is preferable, and a continuous melt polymerization method using a multi-screw extruder is particularly preferable. Furthermore, the polymerization reaction according to the present invention comprises 22
More preferably, a melt polymerization method is employed at a temperature within the range of 0 to 280 ° C. When the polymerization temperature is lower than 220 ° C., the obtained thermoplastic polyurethane has a differential scanning calorimetry (DS).
C) shows an endothermic peak at a temperature higher than 230 ° C., which lowers the melt moldability. If the temperature is higher than 280 ° C., a thermal decomposition reaction occurs, making it difficult to obtain a thermoplastic polyurethane having a high degree of polymerization.

In producing a thermoplastic polyurethane (b) using the above-mentioned polyether polyol, an organic diisocyanate and a chain extender, if a tin-based urethane-forming catalyst is used, a polyether polyol constituting a soft segment , The reaction between the organic diisocyanate constituting the hard segment and the chain extender proceeds quickly, and the thermoplastic resin whose endothermic peak temperature and crystallization enthalpy (ΔH) in differential scanning calorimetry (DSC) are controlled relatively easily It is preferable because polyurethane can be obtained. Examples of the tin-based urethanization catalyst include dialkyltin diacylates such as dibutyltin diacetate and dibutyltin dilaurate, and dialkyltin bismercaptocarboxylic acid ester salts such as dibutyltin bis (ethoxybutyl ester of 3-mercaptopropionate). be able to. The amount of the tin-based urethanization catalyst used is, in terms of tin atom, polyurethane (that is, polyether polyol, organic diisocyanate,
It is preferably 0.001 to 1 ppm based on the total weight of reactive raw material compounds such as a chain extender.

The nitrogen content of the thermoplastic polyurethane (a) is 2.5% by weight or less, preferably 1.0 to 2.5% by weight, and more preferably 1.5 to 2.5% by weight. More preferably, it is 1.7 to 2.5% by weight. When the nitrogen content of the thermoplastic polyurethane (a) exceeds 2.5% by weight, the hardness of the obtained thermoplastic polyurethane composition is increased, and a stretchable film having excellent flexibility and elastic recovery properties is obtained. Molded articles such as sheets cannot be obtained. In addition, thermoplastic polyurethane (b)
Has a nitrogen atom content of 1.5% by weight or more,
The content is preferably from 6.0 to 6.0% by weight, more preferably from 2.0 to 5.0% by weight, and still more preferably from 2.6 to 4.0% by weight. Thermoplastic polyurethane (b)
If the nitrogen atom content of the thermoplastic polyurethane composition is less than 1.5% by weight, the resulting thermoplastic polyurethane composition is inferior in melt moldability and blocking resistance.

The logarithmic viscosity of the thermoplastic polyurethane (a) is determined by dissolving the thermoplastic polyurethane (a) in an N, N-dimethylformamide solution at a concentration of 0.5 g / dl and measuring at 30 ° C. 0.6 to 1.8 dl / g
Is preferably 0.7 to 1.6 dl / g, and more preferably 0.8 to 1.5 dl / g. Use of the thermoplastic polyurethane (a) having a logarithmic viscosity in the above range is preferable because a thermoplastic polyurethane composition having more excellent flexibility and elastic recovery can be obtained. The logarithmic viscosity of the thermoplastic polyurethane (b) is 0 when the thermoplastic polyurethane (b) is dissolved in an N, N-dimethylformamide solution to a concentration of 0.5 g / dl and measured at 30 ° C. .2 to 1.2 dl /
g, more preferably 0.3 to 1.0 dl / g, even more preferably 0.5 to 0.9 dl / g. Use of the thermoplastic polyurethane (b) having a logarithmic viscosity in the above range is preferable because a thermoplastic polyurethane composition having more excellent melt moldability and blocking resistance can be obtained.

The thermoplastic polyurethane (a) of the present invention comprises:
It shows an endothermic peak at 190 ° C. or higher by differential scanning calorimetry (DSC), and the crystallization enthalpy (ΔH) determined from this endothermic peak needs to be less than 1 J / g.
If it is at least J / g, a thermoplastic polyurethane composition having excellent flexibility and elastic recovery properties cannot be obtained. Further, the thermoplastic polyurethane (b) of the present invention shows an endothermic peak in the range of 190 to 230 ° C. by differential scanning calorimetry (DSC), and has a crystallization enthalpy (ΔH) of 1 to 15 J determined from this endothermic peak. / G,
It is preferably 2 to 10 J / g. When the temperature of the endothermic peak is lower than 190 ° C. or when the crystallization enthalpy (Δ
When H) is less than 1 J / g, the resulting thermoplastic polyurethane composition has poor melt moldability and blocking resistance. On the other hand, when the endothermic peak temperature exceeds 230 ° C., or when the crystallization enthalpy (ΔH) exceeds 15 J / g, an unmelted substance is easily generated in the obtained thermoplastic polyurethane composition, and a film, a sheet or the like is formed. When molded into a molded product of the above, cracks, poor appearance due to unmelted material, etc. occur, and a high quality product is not obtained.

The thermoplastic polyurethane composition of the present invention comprises
Based on the total weight of the thermoplastic polyurethanes (a) and (b), 40 to 90% by weight of the thermoplastic polyurethane (a) and 60 to 10% by weight of the thermoplastic polyurethane (b)
, And preferably 45 to 85% by weight of the thermoplastic polyurethane (a) and 55 to 15% by weight of the thermoplastic polyurethane (b). When the content of the thermoplastic polyurethane (a) is less than 40% by weight (when the content of the thermoplastic polyurethane (b) exceeds 60% by weight), the hardness of the thermoplastic polyurethane composition becomes high, so that the Is thin,
It becomes difficult to obtain a film or sheet having a good surface condition, and even if it is obtained, the film or sheet is
Poor flexibility and elastic recovery. When the content of the thermoplastic polyurethane (a) exceeds 90% by weight [the content of the thermoplastic polyurethane (b) is 10% by weight]
Less than), the neck-in phenomenon that occurs when melt-extrusion of a film or sheet with a T-die type extruder or the like is not sufficiently improved, and the thickness generated at both ends of a molded product such as a film or sheet is not improved. The range of the spots is widened, and the productivity of a homogeneous product obtained by trimming the thick spots is reduced. When performing inflation molding, defective phenomena such as uneven thickness and cracks are not sufficiently improved, and the productivity of a homogeneous product is reduced. Furthermore, since the obtained film and sheet also have poor blocking resistance, it is difficult to wind and rewind the film and sheet.

The thermoplastic polyurethane composition of the present invention comprises:
In addition to the thermoplastic polyurethane composition comprising the above thermoplastic polyurethanes (a) and (b), a block copolymer comprising an aromatic vinyl compound polymer block and a conjugated diene polymer block, and a block copolymer of the block copolymer At least one type of hydrogenated product (c) (hereinafter sometimes referred to as “(hydrogenated) block copolymer (c)”)
Based on the total weight of the thermoplastic polyurethanes (a) and (b), it can be contained in a proportion of preferably 5 to 100% by weight, more preferably 5 to 60% by weight. By adding the (hydrogenated) block copolymer (c) at the above ratio, not only a thermoplastic polyurethane composition having further improved blocking resistance and mold release property at the time of melt extrusion molding can be obtained, It is also preferable in inflation molding which requires high blocking resistance, since a molded article such as a film or a sheet can be manufactured smoothly.

The (hydrogenated) block copolymer (c) of the present invention
Examples of the aromatic vinyl compound constituting the aromatic vinyl compound polymer block include styrene and α-
Methylstyrene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, 1-vinylnaphthalene, and the like, One or more of them can be used. Of these, styrene and α-methylstyrene are preferably used. Further, as the conjugated diene constituting the conjugated diene polymer block in the (hydrogenated) block copolymer (c) of the present invention, for example, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,2 3-
Dimethyl-1,3-butadiene, 2-neopentyl-
1,3-butadiene, 1,3-pentadiene, 1,3-
Hexadiene, etc., and one or more of these can be used. Among them, 1,
It is preferable to use 3-butadiene and 2-methyl-1,3-butadiene.

The bonding form of the aromatic vinyl compound polymer block and the conjugated diene polymer block in the (hydrogenated) block copolymer (c) is not particularly limited, and may be linear, branched, radial, or any of those. Any combination of two or more combinations may be used, and a linear combination is preferable. (Hydrogenated) block copolymer (c)
As an example of the above, an aromatic vinyl compound polymer block is represented by X
Thus, when the conjugated diene polymer block is represented by Y,
(XY) n-X, (XY) m, Y- (XY) p
[N, m and p each represent an integer of 1 or more. ], Etc. (hydrogenated) block copolymer. Among these, it is preferable to use a diblock copolymer represented by XY and a triblock copolymer represented by XYX. Further, as the (hydrogenated) block copolymer (c), a copolymer in which part or all of the unsaturated double bond in the conjugated diene polymer block is hydrogenated can also be used. By using such a hydrogenated block copolymer (c), a thermoplastic polyurethane composition having better heat resistance, light resistance and the like can be obtained.

The (hydrogenated) block copolymer (c) preferably has a content of structural units derived from an aromatic vinyl compound of 5 to 75% by weight based on all structural units.
More preferably, it is 0 to 65% by weight. When a (hydrogenated) block copolymer (c) containing a structural unit derived from an aromatic vinyl compound in the above range is used, excellent melt moldability when producing a film or sheet is achieved, and a thin film is achieved. As a result, a material having more excellent blocking resistance, flexibility, and recovery performance such as recovery stress after stretching and residual strain can be obtained.

(Hydrogenated) 230 of the block copolymer (c)
The melt index measured under a load of 2.16 kg at 100 ° C. is preferably 100 g / 10 min or less, and is 80 g or less.
/ 10 minutes or less is more preferable. When the (hydrogenated) block copolymer (c) having the above melt index is used, it is excellent in melt moldability when producing a film or a sheet, a thin film can be achieved, blocking resistance, flexibility, and after elongation. Which has more excellent recovery performance such as recovery stress and residual strain. The melt index of the (hydrogenated) block copolymer (c) in the present invention is AST
It is a value measured according to MD-1238. Further, the JIS A hardness of the (hydrogenated) block copolymer (c) is preferably 30 to 98. The (hydrogenated) block copolymer (c) having a JIS A hardness within this range has more excellent compatibility with the thermoplastic polyurethane, and such (hydrogenated) block copolymer (c) is used. In this case, the molded article obtained from the thermoplastic polyurethane composition is given sufficient flexibility and good mechanical performance. In addition,
JIS of (hydrogenated) block copolymer (c) referred to in the present invention
-A hardness is a value measured according to JIS K-6301.

The thermoplastic polyurethane composition of the present invention contains a releasing agent, a reinforcing agent, a coloring agent, a flame retardant, an ultraviolet absorber, an antioxidant, and a hydrolysis resistance as long as the effects of the present invention are not impaired. Various additives such as improvers, fungicides, antibacterial agents, and stabilizers; various fibers such as glass fibers and polyester fibers; inorganic substances such as talc and silica; and optional components such as various coupling agents, if necessary. Can be blended. The thermoplastic polyurethane composition of the present invention can be produced by mixing the above-mentioned thermoplastic polyurethanes (a) and (b) and other components as required by a desired method. For example, a thermoplastic polyurethane (a) using a vertical tumbler or a horizontal mixer such as a mixer generally used for mixing resin materials,
(B) and, if necessary, other components are premixed at a predetermined ratio, and then melted by heating in a batch or continuous manner using a single-screw or twin-screw extruder, mixing roll, Banbury mixer, or the like. It can be manufactured by kneading.

The thermoplastic polyurethane composition of the present invention comprises:
Melt molding is possible, and various molded articles can be produced smoothly by any molding method such as extrusion molding, inflation molding, injection molding, blow molding, calendar molding, and casting. In particular, since the thermoplastic polyurethane composition of the present invention is excellent in melt extrusion moldability, for example, T
-In molding a film or sheet by a die-type extruder, the neck-in phenomenon in which the width of a molded product such as an extruded film or sheet becomes considerably smaller than the effective width of the T-die has been significantly improved. Since the range of thickness unevenness at both ends of a molded product such as a film or a sheet caused by the phenomenon becomes narrow, the productivity of a product obtained by trimming the thickness unevenness portion is improved. Also, when a molded product such as a film or a sheet extruded from a T-die is taken at a high speed, the entire molded product such as a film or a sheet is not uniformly stretched, resulting in necking or cracking that causes constriction. As a result, a high quality product can be obtained with high productivity. Furthermore, in the molding of films and sheets by an inflation molding machine, defective phenomena such as uneven thickness and cracks of the obtained molded product are remarkably improved, and a high-quality molded product can be obtained with high productivity. further,
Molded products such as films and sheets obtained using the thermoplastic polyurethane composition of the present invention are excellent in stretchability at low stress, recovery performance such as recovery stress or residual strain after elongation, tensile breaking strength and It has excellent mechanical properties such as tensile elongation at break, and has a smooth surface and good surface condition. In particular, it excels in elasticity at low stress and recovery performance such as recovery stress after elongation and residual strain.Effect of these characteristics, stretchable film used for disposable diapers, sanitary napkins, seals, dust proofing, etc. It is particularly preferred to use it for applications. Further, it can be used for various uses such as sheet use for general-purpose conveyor belts, various keyboard sheets, laminated products, various containers, and the like. Furthermore, the film or sheet made of the thermoplastic polyurethane composition of the present invention has excellent adhesiveness with a fibrous substrate made of nonwoven fabric or other fiber cloth, or a substrate made of another polymer film or sheet. Therefore, it is suitable for manufacturing a laminate. For example, the thermoplastic polyurethane composition of the present invention can be melt-extruded into a film or a sheet on a fibrous substrate or another substrate to produce a laminate.

[0031]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. In Examples and Comparative Examples, the nitrogen atom content, logarithmic viscosity, and differential scanning calorimetry (DS
C), melt extrusion moldability, film production state, surface state, blocking resistance, 100% modulus (M10
0), residual strain, adhesiveness and inflation moldability were measured or evaluated by the following methods.

[Nitrogen atom content] The nitrogen atom content was determined by elemental analysis of the thermoplastic polyurethane using an elemental analyzer (Model 240-2, manufactured by PerkinElmer).

[Logarithmic viscosity] Thermoplastic polyurethane was added to an N, N-dimethylformamide solution at a concentration of 0.5 g / dl.
The polyurethane solution was dissolved using an Ubbelohde viscometer and the flow time at 30 ° C. was measured.
The logarithmic viscosity was determined by the following equation. Logarithmic viscosity = [ln (t / t ₀ )] / c [where t is the flow time (seconds) of the polyurethane solution, t ₀
Represents the flow time (second) of the solvent, and c represents the concentration (g / dl) of the polyurethane solution. ]

[Differential Scanning Calorimetry (DSC)] The enthalpy of fusion of the thermoplastic polyurethane was measured using a differential scanning calorimeter (DSC30 manufactured by Mettler). 10 mg of thermoplastic polyurethane was used for the measurement, and the temperature was measured at a rate of 10 ° C./min in a nitrogen gas atmosphere. I asked.

[Melt Extrusion Formability] While discharging a film extruded from a T-die type extruder (25 mmφ, cylinder temperature: 180 to 200 ° C., die temperature: 190 ° C.), the film was discharged 10 cm below the T-die exit. The film width was measured, and the neck-in rate (%) was determined according to the following formula, and was used as an index of melt extrusion moldability. The smaller this value is, the more the neck-in phenomenon is improved, indicating that the melt extrudability is excellent. Neck-in rate (%) = (W ₂ −W ₁ ) / W ₂ × 100 (where W ₁ represents a film width 10 cm below the T-die exit, and W ₂ represents an effective width of the T-die. )

[Film production state, surface state] T-die type extruder (25 mmφ, cylinder temperature: 180)
(200 ° C., dice temperature: 190 ° C.), the film cooled by extruding onto a cooling roll at 30 ° C. was wound at a winding speed of about 3 m / min without using release paper. During the winding, the production state of the film was observed and evaluated according to the following criteria. ：: Without causing a defect phenomenon such as cracking in the film,
Can be wound up normally. Δ: The film was somewhat defective, such as cracks, but could be wound up. ×: A defective phenomenon such as cracking occurred in the film, and winding was impossible. Furthermore, observe the surface condition of the wound film,
平滑 indicates a smooth surface, and X indicates an uneven surface due to poor dispersion.

[Blocking resistance] T-die type extruder (25 mmφ, cylinder temperature: 180-200 ° C.)
Die temperature: 190 ° C.) and extruded onto a cooling roll at 30 ° C. to cool the film to about 3 m without using release paper.
/ Min winding speed. After leaving the wound film at room temperature for 24 hours, the film was rewound by hand, and the resistance at that time was evaluated according to the following criteria. ：: Rewinding is extremely easy without requiring any tensile force. ：: Smooth rewinding is possible. Δ: A considerable tensile force was required, but rewinding was possible. X: The adhesive property is large and rewinding is impossible.

[100% modulus (M100) and residual strain] T-die extruder (25 mmφ, cylinder temperature: 180-200 ° C., die temperature: 190 ° C.)
A test piece (20 cm × 5 cm) was prepared from a 30 μm-thick film formed by using the above method. Using an autograph measuring device IS-500D (manufactured by Shimadzu Corporation), the test piece was stretched 100% at a tensile speed of 300 mm / min at room temperature to measure a 100% modulus (M100). Next, it is returned to the position before elongation at a speed of 300 mm / min (first cycle), and after elongating 100% at the same speed continuously, the residual strain at the time when it is returned to the position before elongation (second cycle) is obtained. Was. The smaller the value of the 100% modulus (M100), the better the extensibility at low stress.
In addition, the smaller the value of the residual strain, the better the recovery performance that returns to the original state after elongation.

[Adhesiveness] T-die type extrusion molding machine (25 m
(φ, cylinder temperature: 180 to 200 ° C, die temperature: 190 ° C), a test piece having a width of 25 mm was prepared from a film having a thickness of 30 µm. An adhesive tape (manufactured by Nichiban Co., Ltd., cloth adhesive tape LSN)
o. 101), and the resistance value when the adhesive tape is peeled off is measured with an autograph measuring device IS-500D.
(Manufactured by Shimadzu Corporation) at room temperature at a tensile speed of 300
It was measured under the condition of mm / min and was used as an index of the adhesiveness to the substrate.

[Inflation Formability] A single screw extruder (50 mmφ, cylinder temperature: 180-200 ° C., die temperature: 190) equipped with an inflation die.
C)), the film was extruded into a tube shape and wound up continuously at a winding speed of about 8 m / min for 8 hours while being pulled up in the vertical direction. The state of film production was observed and evaluated according to the following criteria. ：: The film can be wound up normally without causing defects such as uneven thickness and cracks in the film. Δ: The film was somewhat defective, such as uneven thickness and cracks, but could be wound up. ×: Inferior phenomena such as uneven thickness and cracks occurred on the film, and winding was impossible. Abbreviations for the resins and compounds used in the following Examples and Comparative Examples are shown in Table 1 below.

[0041]

[Table 1]

Example 1 PMP having a number average molecular weight of 3500 as a polymer polyol
A, MDI and BD at 85 ° C., 50 ° C., 5
From the storage tank heated to 0 ° C, polymer polyol / MDI
The mixture was continuously supplied to a twin-screw extruder rotating coaxially by a metering pump so that the molar ratio of / BD became 1 / 3.4 / 2.4, and continuous melt polymerization was performed. At this time, the heating zone of the extruder was divided into three zones of a front part, a middle part and a rear part, and the temperature of the front part was set to 90 to 220 ° C, the temperature of the middle part was set to 260 ° C, and the temperature of the rear part was set to 220 ° C. . The resulting thermoplastic polyurethane melt was continuously extruded in strands into water, then cut with a pelletizer, and the pellets were dried at 80 ° C. for 4 hours. The thermoplastic polyurethane [corresponding to the thermoplastic polyurethane (a)] thus obtained has a nitrogen atom content of 2.
1% by weight, logarithmic viscosity is 0.98 dl / g, and
The crystalline enthalpy (ΔH) determined from the endothermic peak at 190 ° C. or higher by differential scanning calorimetry (DSC) is 0 J /
g. Next, as a polyether polyol, PTMG having a number average molecular weight of 2,000 (SP value = 9.35) containing 1 ppm of dibutyltin diacetate, MDI and BD were heated at 85 ° C, 50 ° C, and 50 ° C, respectively, from storage tanks. , Polyether polyol / MDI / BD
Was continuously supplied to a twin-screw extruder rotating coaxially by a metering pump so that the molar ratio of 1 / 3.52 / 2.57 was obtained, thereby performing continuous melt polymerization. At this time, the heating zone of the extruder is divided into three zones of a front part, a middle part and a rear part, and the temperature of the front part is set to 90 to 220 ° C, the temperature of the middle part is set to 260 ° C, and the temperature of the rear part is set to 220 ° C. did. The resulting polyurethane melt is continuously extruded into water in strands and then cut with a pelletizer,
The pellet was dried at 80 ° C. for 4 hours. The thermoplastic polyurethane [corresponding to the thermoplastic polyurethane (b)] thus obtained has a nitrogen atom content of 3.2% by weight, an logarithmic viscosity of 0.65 dl / g, and differential scanning calorimetry (DSC). Shows an endothermic peak at 209 ° C., and the crystallization enthalpy (ΔH) determined from this endothermic peak is 5.5.
J / g. A mixture obtained by blending the dried pellets of the thermoplastic polyurethanes (a) and (b) prepared above in the ratio shown in Table 2 below was mixed with a single screw extruder (25 mm).
φ, cylinder temperature: 180-200 ° C, die temperature:
(190 ° C.) and melt-kneaded to produce a thermoplastic polyurethane composition. Table 3 below shows the results of the evaluation of the obtained thermoplastic polyurethane composition by the above evaluation method.

[0043]

[Table 2]

[0044]

[Table 3]

Example 2 A thermoplastic polyurethane composition was produced in the same manner as in Example 1 except that the thermoplastic polyurethanes (a) and (b) shown in Table 2 were used at a predetermined ratio. Table 3 shows the results of the evaluation of the obtained thermoplastic polyurethane composition by the above evaluation method.

Example 3 As the thermoplastic polyurethane (a), the number average molecular weight was 20
The PTMG, MDI and BD of No. 00 were continuously melt-polymerized by a twin-screw extruder so that the molar ratios became 1 / 1.8 / 0.8, respectively, and pelletized by a predetermined method. The thermoplastic polyurethane [corresponding to the thermoplastic polyurethane (a)] thus obtained has a nitrogen atom content of 2.0% by weight and an logarithmic viscosity of 0.89 dl / g.
Met. Next, as thermoplastic polyurethane (b),
PTMG (SP value = 9.23), MDI, and BD having a number average molecular weight of 3000 mixed with 1 ppm of dibutyltin diacetate were mixed at a molar ratio of 1 / 5.12 / 4.17, respectively.
Then, continuous melt polymerization was performed using a twin screw extruder, and pelletization was performed by a predetermined method. The thermoplastic polyurethane [corresponding to the thermoplastic polyurethane (b)] thus obtained has a nitrogen atom content of 3.1% by weight, an logarithmic viscosity of 0.82 dl / g, and differential scanning calorimetry (DSC). Shows an endothermic peak at 215 ° C., and the crystallization enthalpy (ΔH) determined from this endothermic peak is 10.
It was 2 J / g. From these, a thermoplastic polyurethane composition was produced in the same manner as in Example 1. Table 3 below shows the results of the evaluation of the obtained thermoplastic polyurethane composition by the above evaluation method.

Example 4 A thermoplastic polyurethane composition was produced in the same manner as in Example 1 except that the thermoplastic polyurethanes (a), (b) and TPS shown in Table 2 were used in predetermined proportions. Table 3 shows the results of the evaluation of the obtained thermoplastic polyurethane composition by the above evaluation method.

Comparative Example 1 As a thermoplastic polyurethane (b), 10 ppm of dibutyltin diacetate was blended with P having a number average molecular weight of 1500.
TMG (SP value = 9.46), MDI and BD were reacted at the ratios shown in Table 2, and ethylene bisstearic acid amide (lubricant) was passed through a vent installed at the rear of the extruder.
With respect to the total weight of PTMG, MDI and BD.
A thermoplastic polyurethane composition was produced in the same manner as in Example 1 except that the amount was 5% by weight. Table 3 shows the results of the evaluation of the obtained thermoplastic polyurethane composition by the above evaluation method.

Comparative Example 2 As the thermoplastic polyurethane (b), a number average molecular weight of 20
Of PTMG, MDI and BD at a ratio shown in Table 2 to the extruder, and the temperature of the intermediate section and the rear section was set at 210
A thermoplastic polyurethane composition was produced in the same manner as in Example 1 except that the reaction was carried out at a temperature of ° C. A film having a thickness of 30 μm was produced from this thermoplastic polyurethane composition.
No film was obtained in which the 00% modulus (M100), residual strain and adhesiveness could be evaluated. Table 3 shows the obtained results.

Comparative Example 3 A thermoplastic polyurethane (b) having a number average molecular weight of 35
A thermoplastic polyurethane composition was produced in the same manner as in Example 1 except that PMPA of 00 (SP value = 10.22) was reacted at the ratio shown in Table 2. Table 3 shows the results of the evaluation of the obtained thermoplastic polyurethane composition by the above evaluation method.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F071 AA12X AA22X AA53 AA75X AA81 AA83 AA87 AF21 AF58 BA01 BB06 BB09 BC01 4J002 BP01Y CK00W CK03W CK04X

Claims (4)

[Claims] 1. A thermoplastic polyurethane composition comprising two types of thermoplastic polyurethanes (a) and (b); (i) the thermoplastic polyurethane (a) has a number average molecular weight of 500 to 8,000. Having a nitrogen atom content of 2.5% by weight or less, and showing an endothermic peak at 190 ° C. or more by differential scanning calorimetry (DSC), comprising a polymer polyol unit, an organic diisocyanate unit and a chain extender unit. Crystallization enthalpy (Δ
(Ii) the thermoplastic polyurethane (b) has a number average molecular weight of 1,500 to 5,000, a polyether polyol unit, an organic diisocyanate unit, and a chain elongation. And a nitrogen atom content of 1.5% by weight or more, and an endothermic peak in the range of 190 to 230 ° C. by differential scanning calorimetry (DSC). ΔH) is 1 to 15 J / g; and 40 to 90% by weight of the thermoplastic polyurethane (a) based on the total weight of the two thermoplastic polyurethanes (a) and (b). And a thermoplastic polyurethane (b) in a proportion of 60 to 10% by weight. 2. A block copolymer composed of an aromatic vinyl compound polymer block and a conjugated diene polymer block and at least one type (c) of a hydrogenated product of the block copolymer is converted into two types of thermoplastics. The thermoplastic polyurethane composition according to claim 1, which is contained in a proportion of 5 to 100% by weight based on the total weight of the polyurethanes (a) and (b). 3. A molded article comprising the thermoplastic polyurethane composition according to claim 1. 4. The molded article according to claim 3, which is a film or a sheet.