JP4236770B2 - Thermoplastic polyurethane - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermoplastic polyurethane having specific crystallinity, and a film, a sheet, and other molded articles made of the thermoplastic polyurethane. The thermoplastic polyurethane of the present invention is excellent in melt moldability, and particularly by melt extrusion molding or inflation molding, it is not only excellent in blocking resistance but also molding of films and sheets excellent in adhesion to various substrates. The product can be manufactured with high productivity.
[0002]
[Prior art]
Thermoplastic polyurethane is attracting attention as an alternative material for rubber and plastic because of its excellent properties such as mechanical performance, abrasion resistance, elastic recovery, oil resistance, and flexibility. Is used in a wide range of applications as a molding material to which can be applied. However, in general thermoplastic polyurethane, when a molded product such as a film or a sheet is melt-extruded using a T-die type extruder or the like, the width of the molded product extruded from the T-die is T-die. A phenomenon (hereinafter referred to as “neck-in phenomenon”) that becomes significantly narrower than the effective width of extrusion occurs, and only a molded product having thickness unevenness at both ends can be obtained. Therefore, in order to obtain a uniform molded product with less thickness unevenness, it is necessary to trim the portions having thickness unevenness at both ends of the molded product, and the productivity of the molded product becomes very poor. Furthermore, since the resulting molded article has poor blocking resistance, it is necessary to produce it using, for example, expensive release paper when producing a molded article such as a film or sheet, which is very laborious and costly. There is a problem that it takes.
[0003]
In recent years, it has been proposed to add lubricants to thermoplastic polyurethanes using high molecular diols with specific number average molecular weights for the purpose of improving the melt-extrusion properties of thermoplastic polyurethanes while retaining the properties of thermoplastic polyurethanes. Has been. For example, Japanese Patent Application Laid-Open No. 8-27376 discloses a heat in which a lubricant is blended with a general high-hardness thermoplastic polyurethane comprising a polyether diol unit, an organic diisocyanate unit and a chain extender unit having a specific number average molecular weight. A plastic polyurethane composition is described.
[0004]
[Problems to be solved by the invention]
However, according to the study by the present inventors, a film or sheet can be obtained using a T-die extruder or the like simply by blending a lubricant with a general thermoplastic polyurethane having a limited number average molecular weight of the polymer polyol. It has been found that the neck-in phenomenon that occurs when melt-extrusion molding such as the above is not sufficiently improved. Furthermore, it has been found that when a molded product such as a film or a sheet is melt-molded from this thermoplastic polyurethane composition using an inflation molding machine, thickness spots and cracks are likely to occur.
[0005]
In addition, since thermoplastic polyurethane has strong adhesiveness and is likely to cause blocking, an amide compound is used for the purpose of non-adhesion, blocking prevention, and release property when manufacturing a film or sheet by melt extrusion molding or the like. It is generally known to add a lubricant such as However, the molded product such as a thermoplastic polyurethane film or sheet obtained by adding this amide compound is said to lose smoothness because the amide compound bleeds out on the surface of the molded product, resulting in numerous irregularities. There is a problem. Further, a molded article such as a thermoplastic polyurethane film or sheet having an amide compound bleed-out on its surface is a laminate of a substrate made of a nonwoven fabric or other fiber fabric, or a substrate made of another polymer film or sheet. There is a problem in that the adhesion performance in the production, specifically the hot melt adhesion performance, etc. is significantly reduced.
[0006]
The inventors of the present invention have already studied in JP-A-9-3321 to provide a thermoplastic polyurethane that is non-adhesive, excellent in blocking resistance and releasability. A thermoplastic polyurethane composition containing a high-polyester thermoplastic polyurethane having high hardness is proposed.
However, even in this thermoplastic polyurethane composition, it is desired to further improve the melt extrusion moldability.
[0007]
Therefore, the object of the present invention is to further improve the neck-in phenomenon that occurs when melt-extrusion molding is performed with a T-die extruder or the like, and the thickness unevenness or crack that occurs when melt-molding is performed with an inflation molding machine. An object of the present invention is to provide a thermoplastic polyurethane capable of producing a molded product such as a film or a sheet excellent in adhesiveness with higher productivity than before. Furthermore, the objective of this invention is providing molded articles, such as a film and sheet | seat which consist of this thermoplastic polyurethane.
[0008]
[Means for Solving the Problems]
As a result of repeated investigations by the present inventors to achieve the above object, in addition to using a thermoplastic polyurethane having specific crystallinity as a thermoplastic polyurethane, a polymer constituting a soft segment of the thermoplastic polyurethane If an ether polymer polyol whose solubility parameter (SP value) is lower than that of an ester polymer polyol is used in the polyol, the difference in SP value between the organic diisocyanate and the hard segment composed of a chain extender increases. The present inventors have found that the phase separation between the soft segment and the hard segment of thermoplastic polyurethane is increased, and the melt moldability and blocking resistance are improved. Furthermore, as a result of repeated studies based on these findings, the use of a polyether-based thermoplastic polyurethane having a specific crystallization enthalpy significantly improves the neck-in phenomenon during melt extrusion with a T-die extruder or the like. In addition, it has excellent anti-blocking properties and can produce molded products such as films and sheets having very favorable mechanical performance with high productivity. The present invention has been completed by finding that a molded product with high quality that is less prone to cracking and can be produced with high productivity.
[0009]
  That is, the present invention relates to a polymer having a number average molecular weight of 1,500 to 5,000.TetramethyleneetherGlicoUnits,4,4'-diphenylmethaneIt consists of a diisocyanate unit and a chain extender unit, has a nitrogen atom content of 1.5% by weight or more, and shows an endothermic peak in the range of 190 to 230 ° C. by differential scanning calorimetry (DSC). Crystallization enthalpy (ΔH) of 1-15 J / gFor extrusion or inflation moldingThermoplastic polyurethaneA thermoplastic polyurethane produced by using 0.001 to 1 ppm of tin-based urethanization catalyst in terms of tin atoms based on the weight of the polyurethane.It is. And this invention is molded articles, such as a film and a sheet which consist of this thermoplastic polyurethane.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
  The thermoplastic polyurethane used in the present invention is a polyTetramethyleneetherGlicoUnits,4,4'-diphenylmethaneConsists of diisocyanate units and chain extender units.
  The thermoplastic polyurethane of the present inventionTetramethyleneetherGlicoExamples of the polyol compound for constituting the polyol unit are obtained by ring-opening polymerization of a cyclic ether in the presence of a polyol.RuRitetramethylene ether glycoLeTo mentionwear.
  The polyTetramethyleneetherGlicoThe number average molecular weight of the rubber is 1,500 to 5,000, preferably 1,800 to 4,000. Poly having a number average molecular weight within this rangeTetramethyleneetherGlicoBy using a rubber, a thermoplastic polyurethane having more excellent melt moldability and blocking resistance can be obtained. Note that the term polyTetramethyleneetherGlicoThe number average molecular weight of the rubber is a number average molecular weight calculated based on the hydroxyl value measured according to JIS K-1557.
[0011]
  The polyTetramethyleneetherGlicoThe SP value of the tool is preferably 5 to 10, and more preferably 6 to 9.5. Poly with SP values in this rangeTetramethyleneetherGlicoBy using the4,4'-diphenylmethaneSince the difference in SP value (about 12.5) between the diisocyanate and the hard segment composed of the chain extender is increased, a thermoplastic polyurethane having better melt moldability and blocking resistance can be obtained. In addition, the poly used in the present inventionTetramethyleneetherGlicoThe SP value of the tool is the SP value calculated based on the method of Fedors (see “Basic Science of Coating” by Yuji Harasaki).
[0012]
  Furthermore, the thermoplastic polyurethane of the present invention contains nitrogen atomsrateIs 1.5% by weight or more and has a specific crystallization enthalpy, which significantly improves the neck-in phenomenon during melt extrusion molding with a T-die extruder, etc., and also has blocking resistance. It is possible to produce excellent molded products such as films and sheets with excellent mechanical performance with high productivity, and even when melt molding with an inflation molding machine, thickness unevenness and cracks are less likely to occur. Good molded products can be produced with high productivity.
[0013]
  As organic diisocyanate for constituting organic diisocyanate unit of thermoplastic polyurethane4, 4'-diphenylmethane diisocyanate usedThe
[0014]
Furthermore, as a compound for constituting the chain extender unit of thermoplastic polyurethane, any of chain extenders conventionally used in the production of thermoplastic polyurethanes may be used, but it can react with an isocyanate group. It is preferable to use a low molecular weight compound having a molecular weight of 300 or less and having 2 or more active hydrogen atoms 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; diamines such as hydrazine, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine and derivatives thereof, phenylenediamine, tolylenediamine, xylenediamine, adipic acid dihydrazide, and isophthalic acid dihydrazide; Examples thereof include 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, it is preferable to use an aliphatic diol having 2 to 10 carbon atoms, and it is more preferable to use 1,4-butanediol.
[0015]
In the present invention, the nitrogen content of the thermoplastic polyurethane is 1.5% by weight or more, preferably 1.5 to 6.0% by weight, and 2.0 to 5.0% by weight. More preferably, it is 2.6 to 4.0% by weight, more preferably 3.0 to 4.0% by weight. When the nitrogen content of the thermoplastic polyurethane is less than 1.5% by weight, the melt-molding property and blocking resistance of the resulting thermoplastic polyurethane are inferior.
[0016]
The logarithmic viscosity of thermoplastic polyurethane is 0.2 to 1.2 dl / g when measured at 30 ° C. by dissolving thermoplastic polyurethane in N, N-dimethylformamide solution to a concentration of 0.5 g / dl. It is preferable that it is 0.3-1.0 dl / g, and it is further more preferable that it is 0.5-0.9 dl / g. It is preferable to use a thermoplastic polyurethane having a logarithmic viscosity in the above range because a thermoplastic polyurethane having more excellent melt moldability and blocking resistance can be obtained.
[0017]
The thermoplastic polyurethane of the present invention has an endothermic peak in the range of 190 to 230 ° C. by differential scanning calorimetry (DSC), and the crystallization enthalpy (ΔH) obtained from this endothermic peak is 1 to 15 J / g. Is required and is preferably 2 to 10 J / g. When the temperature of the endothermic peak is less than 190 ° C., or when the crystallization enthalpy (ΔH) is less than 1 J / g, the resulting thermoplastic polyurethane has poor melt moldability and blocking resistance. On the other hand, when the endothermic peak temperature exceeds 230 ° C., or the crystallization enthalpy (ΔH) exceeds 15 J / g, cracks and Defects such as poor appearance due to unmelted materials occur, which is not preferable.
[0018]
Further, the thermoplastic polyurethane of the present invention includes a release agent, a reinforcing material, a colorant, a flame retardant, an ultraviolet absorber, an antioxidant, a hydrolysis resistance improver, as long as the effects of the present invention are not impaired. Additives such as 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 should be added as required Can do.
[0019]
  In the present invention, the method for producing the thermoplastic polyurethane is not particularly limited,TetramethyleneetherGlicoAnd4,4'-diphenylmethaneUsing a diisocyanate and a chain extender, it may be produced by either a prepolymer method or a one-shot method. Of these, the polyTetramethyleneetherGlicoAnd hard segments4,4'-diphenylmethaneA diisocyanate and a chain extender have a large difference in SP value and are incompatible with each other. Therefore, a melt polymerization method capable of being rapidly stirred and mixed at a high shear rate is preferable, and a continuous melt weight using a multi-screw extruder is particularly preferable. It is more preferable to adopt a legal method. Furthermore, in the present invention, the polymerization reaction is more preferably a melt polymerization method at a temperature within the range of 220 to 280 ° C. The thermoplastic polyurethane obtained when the polymerization temperature is lower than 220 ° C shows an endothermic peak at a temperature higher than 230 ° C by differential scanning calorimetry (DSC), so that the melt moldability is lowered, and when it is higher than 280 ° C, the thermal decomposition reaction is caused. Occurs, and it becomes difficult to obtain a thermoplastic polyurethane having a high degree of polymerization.
  Said polyTetramethyleneetherGlicoAnd4,4'-diphenylmethaneIn producing a thermoplastic polyurethane by reacting a diisocyanate and a chain extender, the mixing ratio of each component is appropriately determined in consideration of the hardness to be imparted to the target thermoplastic polyurethane.TetramethyleneetherGlicoFor 1 mole of active hydrogen atoms possessed by the chain and the chain extender,4,4'-diphenylmethaneIt is preferable to use each component in such a ratio that the isocyanate group contained in the diisocyanate is 0.9 to 1.2 mol. It is preferable to use each component in the above ratio because a thermoplastic polyurethane excellent in melt moldability, blocking resistance and the like can be obtained.
[0020]
  In addition, in the production of thermoplastic polyurethane, if a tin-based urethanization catalyst is used for the urethanization reaction, the poly- mer constituting the soft segment is used.TetramethyleneetherGlicoAnd hard segments4,4'-diphenylmethaneThe reaction between the diisocyanate and the chain extender proceeds rapidly, and a thermoplastic polyurethane having a controlled endothermic peak temperature and crystallization enthalpy (ΔH) in differential scanning calorimetry (DSC) can be obtained relatively easily.
[0021]
  Examples of the tin-based urethanization catalyst include dialkyltin diamerates such as dibutyltin diacetate and dibutyltin dilaurate, and dialkyltin bismercaptocarboxylic acid ester salts such as dibutyltin bis (3-mercaptopropionic acid ethoxybutyl ester) salt. be able to. The amount of these tin-based urethanization catalysts used is polyurethane (i.e.TetramethyleneetherGlico,4,4'-diphenylmethane0.001 to 1 ppm relative to the total weight of the reactive raw material compounds such as diisocyanate and chain extender)The
[0022]
  The thermoplastic polyurethane of the present invention thus obtained can be melt-molded and extruded.OrInflationIn shapeTherefore, various molded products can be manufactured smoothly. In particular, since the thermoplastic polyurethane of the present invention is excellent in melt extrusion moldability, for example, in molding of a film or sheet by a T-die type extruder, the film or sheet extruded beyond the effective width of the T-die The neck-in phenomenon where the width of the molded product becomes considerably smaller, etc. has been remarkably improved, and the range of thickness unevenness at both ends of the molded product such as a film or sheet caused by the neck-in phenomenon is narrowed. Productivity of the product obtained by trimming the part of the is improved. In addition, necking, cracking, and unmelted material that causes necking without stretching the entire molded product such as a film or sheet even when the molded product such as a film or sheet extruded from a T-die is pulled at a high speed. As a result, it is difficult for defects such as appearance defects due to the above to occur. Furthermore, even in the molding of films and sheets using an inflation molding machine, defective phenomena such as appearance defects due to uneven thickness, cracks, unmelted materials, etc. of the molded product are remarkably improved, and high-quality molded products are high. Obtained with productivity.
[0023]
Molded articles such as films and sheets obtained using the thermoplastic polyurethane of the present invention are excellent in mechanical performance represented by tensile breaking strength and tensile breaking elongation, and have a smooth surface. Since the surface state is also good, it can be used for film applications such as paper diapers, sanitary napkins, eye seals, and dust prevention. Moreover, it can also be used for various uses, such as sheet | seat uses, such as a general-purpose conveyor belt, various keyboard sheets, a laminate, and various containers.
Furthermore, since the film and sheet of the present invention are excellent in adhesiveness with non-woven fabrics and other fabrics made of other polymers, and substrates made of other polymer films and sheets, etc. Is also suitable. For example, the thermoplastic polyurethane of the present invention can be melt-extruded into a film or sheet on a fibrous base material or other base material to produce a laminate.
[0024]
【Example】
The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, nitrogen atom content, logarithmic viscosity, differential scanning calorimetry (DSC), melt extrusion moldability, film production state, surface state, blocking resistance, 100% modulus (M100), adhesion Properties and inflation moldability were measured or evaluated by the following methods.
[0025]
[Nitrogen atom content]
It calculated | required by the elemental analysis of a thermoplastic polyurethane using the elemental-analyzer (Perkin-Elmer 240-2 type).
[0026]
[Logarithmic viscosity]
A thermoplastic polyurethane is dissolved in N, N-dimethylformamide solution so as to have a concentration of 0.5 g / dl, and the flow time of the polyurethane solution at 30 ° C. is measured using an Ubbelohde viscometer. The viscosity was determined.
Logarithmic viscosity = [ln (t / t₀)] / C
[Wherein, t is the flow time (seconds) of the polyurethane solution, t₀Is the solvent flow time (seconds), and c is the polyurethane solution concentration (g / dl). ]
[0027]
[Differential scanning calorimetry (DSC)]
Using a differential scanning calorimeter (Mettler DSC30), the melting enthalpy of the thermoplastic polyurethane was measured. For measurement, 10 mg of thermoplastic polyurethane was used and measured at a temperature increase rate of 10 ° C./min in a nitrogen gas atmosphere. From the temperature of the endothermic peak and the endothermic peak area in the range of 190 to 230 ° C., crystallization enthalpy (ΔH) Asked.
[0028]
[Melt extrusion moldability]
While discharging the film extruded from a T-die extrusion machine (25 mmφ, cylinder temperature: 180 to 200 ° C., die temperature: 200 ° C.), the film width 10 cm below the T-die outlet is measured, and according to the following formula: The neck-in rate (%) was determined and used as an index of melt extrusion moldability. The smaller this value, the better the neck-in phenomenon and the better the melt extrusion moldability.
Neck-in rate (%) = (W₂-W₁) / W₂× 100
(Where₁Is the film width 10 cm below the T-die exit,₂Indicates the effective width of the T-die. )
[0029]
[Film production state, surface state]
The film cooled by being extruded from a T-die extrusion machine (25 mmφ, cylinder temperature: 180 to 200 ° C., die temperature: 200 ° C.) onto a cooling roll at 30 ° C. without using a release paper is about 2.5 m / Winding up at a winding speed of minutes. During the winding, the production state of the film was observed and evaluated according to the following criteria.
○: The film can be wound up normally without causing defects such as cracks.
Δ: Some defects such as cracks occurred in the film, but it can be wound.
X: Defects such as cracks occur in the film, and winding is impossible.
The “breaking in the film” referred to here indicates a state where the film is torn.
Furthermore, the surface state of the wound film was observed, and a smooth film was marked with ◯, and a film with irregularities on the surface due to poor dispersion was marked with x.
[0030]
[Thick spots]
  The film cooled by being extruded from a T-die extrusion machine (25 mmφ, cylinder temperature: 180 to 200 ° C., die temperature: 200 ° C.) onto a cooling roll at 30 ° C. without using a release paper is about 2.5 m / Winding up at a winding speed of minutes. The film was cut in the extrusion width direction, the film thickness was measured using a micrometer at regular intervals, and the following evaluation was performed.
  ○: Thickness unevenness of film {50μm± (5 μm or less)}.
  Δ: FilmofThickness spots {50μm± (over 5 μm and below 15 μm)}.
  ×: FilmofThickness spots {50μm± (over 15 μm)}.
[0031]
[Blocking resistance]
The film cooled by being extruded from a T-die extrusion machine (25 mmφ, cylinder temperature: 180 to 200 ° C., die temperature: 200 ° C.) onto a cooling roll at 30 ° C. without using a release paper is about 2.5 m / Winding up at a winding speed of minutes. The wound film was allowed to stand at room temperature for 24 hours and then rewound by hand, and the resistance at that time was evaluated according to the following criteria.
A: Rewinding is possible very easily without requiring any tensile force.
○: Smooth rewinding is possible.
Δ: A considerable tensile force was required, but it was possible to rewind.
×: High stickiness and impossible to rewind.
[0032]
[100% modulus (M100)]
A test piece (20 cm × 5 cm) was prepared from a film having a thickness of about 50 μm formed using a T-die type extruder (25 mmφ, cylinder temperature: 180 to 200 ° C., die temperature: 200 ° C.). The test piece was stretched 100% at a tensile speed of 300 mm / min at room temperature and measured for 100% modulus (M100) using an autograph measuring apparatus IS-500D (manufactured by Shimadzu Corporation).
[0033]
〔Adhesiveness〕
A test piece having a width of 25 mm was prepared from a film having a thickness of about 50 μm formed using a T-die type extruder (25 mmφ, cylinder temperature: 180 to 200 ° C., die temperature: 200 ° C.). Adhesive tape (Nichiban Co., Ltd., cloth adhesive tape LS No. 101) is attached to this test piece, and the resistance value when this adhesive tape is peeled off is measured using an autograph measuring device IS-500D (manufactured by Shimadzu Corporation). Then, the measurement was performed at room temperature under the condition of a tensile speed of 300 mm / min, and used as an index of adhesion to the substrate.
[0034]
[Inflation formability]
At a winding speed of about 8 m / min, the film extruded from a single-screw extruder (50 mmφ, cylinder temperature: 180 to 200 ° C., die temperature: 200 ° C.) attached with an inflation die is pulled up in the vertical direction. It was wound up continuously for 8 hours. The film production state was observed and evaluated according to the following criteria.
○: The film can be wound up normally without causing defects such as appearance defects due to uneven thickness, cracks, unmelted material, etc.
Δ: Some defects in appearance due to uneven thickness, cracks, unmelted material, etc. occurred on the film, but it can be wound up.
X: Defects such as appearance defects due to thickness irregularities, cracks, unmelted material, etc. occur violently on the film, and winding is impossible.
Abbreviations relating to resins and compounds used in the following Examples and Comparative Examples are shown below.
[0035]
  Example 1
  As a polyether polyol, PTMG (SP value = 9.35) having a number average molecular weight of 2000 blended with 1 ppm of dibutyltin diacetate, MDI, and BD were heated to 85 ° C., 50 ° C., and 50 ° C., respectively. / MDI / BD was continuously fed to a twin screw extruder rotating coaxially by a metering pump so that the molar ratio was 1 / 3.57 / 2.57, and continuous melt polymerization was performed. . At this time, the heating zone of the extruder was divided into three zones, a front part, an intermediate part and a rear part, and the temperature of the intermediate part was set to 260 ° C and the temperature of the rear part was set to 220 ° C. The resulting polyurethane melt was continuously extruded into water as a strand, then cut with a pelletizer, and the pellets were dried at 80 ° C. for 4 hours. The analysis results of the thermoplastic polyurethane thus obtained are shown in Table 1 below.
  Its nitrogen atom contentrateIs 3.2 wt%, logarithmic viscosity is 0.65 dl / g, and differential scanning calorimetry (DSC) shows an endothermic peak at 209 ° C. The crystallization enthalpy (ΔH) determined from this endothermic peak is 5.5 J / G.
  Moreover, the result of evaluating the obtained thermoplastic polyurethane by the above evaluation method is shown in Table 2 below.
[0036]
[Table 1]
[0037]
[Table 2]
[0038]
Examples 2-3
A thermoplastic polyurethane was produced in the same manner as in Example 1 except that polyether polyol / MDI / BD was reacted in the ratio shown in Table 1. The analysis results of the obtained thermoplastic polyurethane are shown in Table 1. In addition, Table 2 shows the results of evaluating the obtained thermoplastic polyurethanes by the above evaluation method.
[0039]
Comparative Example 1
As a polyether polyol, a PTMG (SP value = 9.46) having a number average molecular weight of 1500 blended with 10 ppm of dibutyltin diacetate, MDI and BD were reacted at a ratio shown in Table 1, and a vent installed at the rear of the extruder. A thermoplastic polyurethane composition was prepared in the same manner as in Example 1 except that ethylenebisstearic acid amide (lubricant) was added from the mouth so as to be 0.5% by weight based on the total weight of PTMG, MDI and BD. Manufactured. Table 1 shows the analysis results of the obtained thermoplastic polyurethane composition. About the obtained thermoplastic polyurethane composition, it evaluated by said evaluation method. The adhesiveness was as weak as 250 g / 25 mm and could not withstand actual use. The results are shown in Table 2.
[0040]
Comparative Example 2
Example 1 except that PTMG, MDI and BD having a number average molecular weight of 2000 as a polyether polyol were supplied to the extruder at a ratio shown in Table 1 and the temperature of the intermediate part and the rear part was reacted at 210 ° C. A thermoplastic polyurethane was produced in the same manner. The analysis results of the obtained thermoplastic polyurethane are shown in Table 1. A film having a thickness of about 50 μm was produced from this thermoplastic polyurethane. However, since film cracking occurred, a film capable of evaluating blocking resistance, 100% modulus (M100) and adhesiveness could not be obtained. The obtained results are shown in Table 2.
[0041]
Comparative Example 3
A thermoplastic polyurethane was prepared in the same manner as in Example 1, except that PMPA (SP value = 10.22) having a number average molecular weight of 3500 was reacted as a polyester diol at a ratio shown in Table 1 instead of the polyether polyol. Manufactured. The analysis results of the obtained thermoplastic polyurethane are shown in Table 1. Table 2 shows the results of evaluation of the obtained thermoplastic polyurethane by the above evaluation method.

Claims (4)

Polytetramethylene ether glycol units having a number average molecular weight of 1,500 to 5,000, composed of 4,4'-diphenylmethane diisocyanate unit and chain extender units, the nitrogen atom content be 1.5 wt% or more And an endothermic peak in the range of 190 to 230 ° C. by differential scanning calorimetry (DSC), and the heat for extrusion molding or inflation molding in which the crystallization enthalpy (ΔH) obtained from this endothermic peak is 1 to 15 J / g. A thermoplastic polyurethane produced by using a 0.001 to 1 ppm tin-based urethanization catalyst in terms of tin atoms based on the weight of the polyurethane .   The thermoplastic polyurethane according to claim 1, having a logarithmic viscosity of 0.2 to 1.2 dl / g.   A molded article comprising the thermoplastic polyurethane according to claim 1.   The molded article according to claim 3, which is a film or a sheet.