THERMOPLASTIC ALIPHATIC POLYURETHANE POLYMER HAVING A LOWER CRYSTALLIZATION ENTHALPY
The present invention relates to thermoplastic aliphatic polyurethane polymers, in which the ratio M z / M w is in a range from 2.3 to 6 and which have a degree of crystallinity χ in the range from 10% to 51%, to compositions containing such polyurethane polymers, to a method for the production thereof and to the use of these polyurethane polymers.
1 . A thermoplastic aliphatic polyurethane polymer, wherein the ratio M z / M w of the thermoplastic aliphatic polyurethane polymer is in a range from 2.3 to 6, where M z is the centrifuge-average molar mass and M w is the mass-average molar mass, in each case determined by gel permeation chromatography, in which the sample was dissolved in a solution of potassium trifluoroacetate in hexafluoroisopropanol at a concentration of 2 mg/cm 3 and a polymethylmethacrylate standard was used, and the thermoplastic aliphatic polyurethane polymer has a degree of crystallinity χ in the range from 10% to 51%, where the degree of crystallinity χ is determined according to the following equation:
χ=(Δ H C,polymer /ΔH crystal,100% )·100%,
where ΔH C,polymer is the measured enthalpy of crystallization in [J/g] of the thermoplastic aliphatic polyurethane polymer, determined by differential scanning calorimetry (DSC) in accordance with DIN EN ISO 11357-1:2017-02 at a cooling rate of 10 K/m in in the range from 250° C. to 20° C., and
ΔH crystal,100% is the enthalpy of fusion of the corresponding 100%-crystalline thermoplastic aliphatic polyurethane polymer in [J/g], determined by differential scanning calorimetry and X-ray scattering analysis.
2 . The thermoplastic aliphatic polyurethane polymer as claimed in claim 1 , wherein the thermoplastic aliphatic polyurethane polymer has a degree of crystallinity χ in the range from 20% to 51%.
3 . The thermoplastic aliphatic polyurethane polymer as claimed in claim 1 , wherein the ratio M w / M n of the thermoplastic aliphatic polyurethane polymer is in a range from 3 to 8.
where M n is the number-average molar mass and M w is the mass-average molar mass, in each case determined by gel permeation chromatography, in which the sample was dissolved in a solution of potassium trifluoroacetate in hexafluoroisopropanol at a concentration of 2 mg/cm 3 and a polymethylmethacrylate standard was used.
4 . The thermoplastic aliphatic polyurethane polymer as claimed in claim 1 , wherein the ratio M z / M w of the thermoplastic aliphatic polyurethane polymer is in a range from 2.5 to 5, where M z is the centrifuge-average molar mass and M w is the mass-average molar mass, in each case determined by gel permeation chromatography, in which the sample was dissolved in a solution of potassium trifluoroacetate in hexafluoroisopropanol at a concentration of 2 mg/cm 3 and a polymethylmethacrylate standard was used.
5 . The thermoplastic aliphatic polyurethane polymer as claimed in claim 1 , wherein the thermoplastic aliphatic polyurethane polymer is obtained by reacting one or more aliphatic polyisocyanates having a molecular weight in the range from ≥140 g/mol to ≤400 g/mol, with one or more aliphatic polols.
6 . The thermoplastic aliphatic polyurethane polymer as claimed in claim 1 , wherein the thermoplastic aliphatic polyurethane polymer consists to an extent of at least 80% by weight of the reaction product of the reaction of hexamethylene-1,6-diisocyanate with butane-1,4-diol, based on the total mass of the thermoplastic aliphatic polyurethane polymer.
7 . The thermoplastic aliphatic polyurethane polymer as claimed in claim 1 , characterized in that the thermoplastic aliphatic polyurethane polymer has a peak crystallization temperature in the range from 130° C. to 145° C., determined by differential scanning calorimetry (DSC) in accordance with DIN EN ISO 11357-1:2017-02.
8 . A process for preparing a thermoplastic aliphatic polyurethane polymer as claimed in claim 1 , wherein, in a first step, at least one or more aliphatic polyisocyanates are reacted with one or more aliphatic polyols, optionally in the presence of a catalyst and/or auxiliaries and additives, to give at least one prepolymer, and the at least one prepolymer obtained in the first step is reacted in a second step with at least one chain extender to give the thermoplastic aliphatic polyurethane polymer.
9 . The process as claimed in claim 8 , wherein, independently of one another, as aliphatic polyisocyanate, an aliphatic diisocyanate is used and, as aliphatic polyol, an aliphatic diol is used.
10 . A composition comprising at least one thermoplastic aliphatic polyurethane polymer as claimed in claim 1 and at least one additive and/or a further thermoplastic polymer.
11 . A thermoplastic molding compound, comprising at least one composition as claimed in claim 10 .
12 . A molding, film and/or fiber, comprising at least one thermoplastic polyurethane polymer as claimed in claim 1 , at least one thermoplastic molding compound as claimed in claim 11 , or at least one composition as claimed in claim 10 .
13 . A method of producing molding, film, and/or fiber, comprising producing the molding, film, and/or fiber with the thermoplastic polyurethane polymer as claimed in claim 1 , a molding compound including the thermoplastic polyurethane polymer as claimed in claim 1 , or composition including the thermoplastic polyurethane polymer as claimed in claim 1 .
14 . A method of producing a composition, a thermoplastic molding compound, or a polyurethane dispersion, comprising producing the composition, the thermoplastic molding compound, or the polyurethane dispersion with the thermoplastic aliphatic polyurethane polymer as claimed in claim 1 .
15 . An article comprising the thermoplastic aliphatic polyurethane polymer as claimed in claim 1 or a composition including the thermoplastic aliphatic polyurethane polymer as claimed in claim 1 .