Ski boots with temperature-independent modulus of elasticity

Abstract

The present invention relates to a thermoplastic polyurethane (TPU-1) obtained or obtainable by reaction of an isocyanate composition (IZ) comprising MDI with a polyol composition (PZ), wherein the polyol composition (PZ) comprises at least one polyol (P1) and a chain extender (KV1), wherein the polyol (P1) is selected from polytetrahydrofurans having an average molecular weight Mn in the range from 1200 to 2000 g/mol and the chain extender (KV1) is selected from the group consisting of 1,3-propanediol, 1,4-butanediol and 1,6-hexanediol and also to a process for producing a ski shoe or a part of a ski shoe from the thermoplastic polyurethane according to the invention and to the ski shoe or part of a ski shoe per se.

Claims

1. A process for producing a ski shoe or a part of a ski shoe, the process comprising: producing a ski shoe or a part of a ski shoe from a thermoplastic polyurethane (TPU-1) obtained by reaction of an isocyanate composition (IZ) comprising 4,4-diphenylmethanediisocyanate (MDI) with a polyol composition (PZ), comprising a polyol (P1) and a chain extender (KV1), wherein the polyol (P1) comprises a polytetrahydrofuran having an average molecular weight Mn in a range of from 1300 to 1700 g/mol, wherein the chain extender (KV1) comprises 1,3-propanediol, 1,4-butanediol, or 1,6-hexanediol, and wherein the thermoplastic polyurethane has a hard phase fraction greater than 0.40, and wherein the hard phase fraction is defined by formula (I) $\begin{array}{cc}\mathrm{Hard}\mathrm{phase}\mathrm{fraction}=\left\{\underset{x=1}{\overset{x}{.Math.}}\left[\left(m_{KVx}/M_{\mathrm{KVx}}\right)*M_{Iso}+m_{\mathrm{KVx}}\right]\right\}/m_{ges},& \left(I\right)\end{array}$ wherein M.sub.Kvx is molar mass of the chain extender x in g/mol, m.sub.Kvx is mass of the chain extender x in g, M.sub.Iso is molar mass of the isocyanate in g/mol, m.sub.ges is total mass of all starting materials in g, and x is a number of chain extenders.

2. The process of claim 1, wherein the thermoplastic polyurethane (TPU-1) is processed by injection molding in the producing.

3. The process of claim 1, wherein the chain extender (KV1) is 1,4-butanediol.

4. The process of claim 1, wherein the thermoplastic polyurethane of the ski shoe or the part has a Charpy notched impact strength at ?30? C. according to DIN EN ISO 179-1/1 eA of greater than 10 kJ/m.sup.2.

5. The process of claim 1, wherein the thermoplastic polyurethane has an elastic modulus of greater than 200 MPa.

6. The process of claim 1, wherein the polyol (P1) comprises a polytetrahydrofuran having an average molecular weight Mn in a range of from 1400 to 1700 g/mol.

7. The process of claim 6, wherein the chain extender (KV1) is 1,4-butanediol.

8. The process of claim 1, wherein the thermoplastic polyurethane has a hard phase fraction greater than 0.5.

9. The process of claim 1, wherein the thermoplastic polyurethane has an elastic modulus of 400 to 1,100 MPa.

10. The process of claim 1, wherein the thermoplastic polyurethane has an elastic modulus of 800 to 1,000 MPa.

11. The process of claim 1, wherein the thermoplastic polyurethane of the ski shoe or the part has a Charpy notched impact strength at ?30? C. according to DIN EN ISO 179-1/1 eA of greater than 30 kJ/m.sup.2.

Description

EXAMPLES

1. Example 1Raw Materials

(1) Poly PTHF? 1000: Polytetrahydrofuran 1000, CAS number: 25190-06-1, BASF SE, 67056 Ludwigshafen, GERMANY, intermediates division. Poly PTHF? 2000: Polytetrahydrofuran 2000, CAS number: 25190-06-1, BASF SE, 67056 Ludwigshafen, GERMANY, intermediates division. 1,4-butanediol: butane-1,4-diol, CAS number: 110-63-4, BASF SE, 67056 Ludwigshafen, GERMANY, intermediates division. Lupranat MET: 4,4-methylenediphenyl diisocyanate, CAS number: 101-68-8, BASF SE, 67056 Ludwigshafen, GERMANY Color masterbatch 1: Elastollan Konz 315 F (red), BASF Polyurethanes GmbH, Elastogranstrasse 60, 49448 Lemforde Color masterbatch 2: Elastollan Konz 530/1 (blue), BASF Polyurethanes GmbH, Elastogranstrasse 60, 49448 Lemf?rde

2. Example 2Production of Materials

(2) Materials A-N were produced using a ZSK 58 twin-screw extruder from Werner and Pfleiderer Stuttgart with a 48 D screw divided into 12 barrels. Pelletization was carried out using customary underwater pelletization apparatus from Gala (UWG). The formulations for the individual materials are summarized in table 1. TPU materials having average molar weights of the polyol component greater than 2000 Dalton were not producible.

3. Determination of Properties

(3) Mechanical properties were determined on injection molded bodies. Determination of density was performed according to DIN EN ISO 1183-1 (A), hardness according to DIN 53505, tensile strength, breaking elongation and elastic moduli according to DIN EN ISO 527, tear propagation resistance according to DIN ISO 34-1, B (b), notched impact strengths according to DIN EN ISO 179-1/1eA and abrasion according to DIN 53516. The properties for the individual materials are summarized in table 1.

4. Notched Impact Strengths at Low Temperatures

(4) The inventive examples (EB) in table 1 illustrate that the use of a PTHF having average molar weights in the range of 1400-1700 affords materials having a high impact strength at low temperatures. Materials having approximately identical stiffness at 20? C. were to be compared. Thus for example for the inventive material J a notched impact strength of 117 kJ/m.sup.2 was measured at ?30? C. while for the noninventive material K a notched impact strength of 8 kJ/m.sup.2 was determined at ?30? C. Similarly, the inventive materials A and E may be compared to the noninventive material D for example. For material A a notched impact strength of 120 kJ/m.sup.2 was measured at ?30? C. while for the noninventive material D a notched impact strength of 9 kJ/m.sup.2 was determined at ?30? C. For material A a notched impact strength of 110 kJ/m.sup.2 was measured at ?20? C. while for the noninventive material D a notched impact strength of 15 kJ/m.sup.2 was determined at ?20? C. Furthermore, the examples D to I, all having a hard phase fraction of 53%, show that the notched impact strength at ?30? C. for the inventive materials (E-I) having average molar weights for the PTHF in the range of 1400-1700 are always above 20 kJ/m.sup.2. Despite the much lower elastic modulus at 20? C. the noninventive example D is markedly below 20 kJ/m.sup.2 for notched impact strengths at ?30? C.

5. Stiffening at Low Temperatures

(5) The inventive examples (EB) in table 1 illustrate that the use of a PTHF having average molar weights in the range of 1400-1700 affords materials whose stiffness (elastic modulus) increases only moderately at low temperatures. Materials having approximately identical stiffness at 20? C. were to be compared. Thus for example for the inventive material J an increase in the elastic modulus to 180% is registered from 20? C. to ?30? C. while for the noninventive material K an increase to 340% is determined. Similarly, the inventive material A may be compared to the noninventive material D for example. For the inventive material A an increase in the elastic modulus of 260% is registered from 20? C. to ?30? C. while for the noninventive material D an increase in the elastic modulus to 660% is determined.

(6) TABLE-US-00001 TABLE 1 Formulations and properties of materials A-G Material A B C D E F G EB inv. Example/VB comp. EB EB EB VB EB EB EB example HP fraction [%] 47 49 51 53 53 53 53 Average molar weight of PTHF 1700 1700 1700 1000 1200 1400 1500 [Dalton] Poly THF 2000 OHN: 56.1 [g] 37.64 36.16 34.76 0 12.83 22.52 26.54 Poly THF 1000 OHN: 112.2 [g] 8.06 7.74 7.44 37.09 25.58 16.85 13.24 Lupranat MET [g] 40.9 42.15 43.34 47.94 46.62 45.64 45.23 Butanediol, 1,4- [g] 12.31 12.85 13.37 13.87 13.87 13.89 13.89 Density [g/cm.sup.3] 1.14 1.14 1.15 1.17 1.16 1.16 1.16 Hardness [Shore D] 53 54 57 59 59 60 60 Tensile strength [MPa] 37 42 43 57 42 49 41 Elongation at break [%] 370 370 380 430 360 370 330 Tear propagation resistance 96 107 114 171 176 171 168 [kN/m] Abrasion [mm.sup.3] 40 40 43 32 51 58 50 Elastic modulus at 20? C. [MPa] 281 382 435 205 353 528 591 Elastic modulus at 0? C. [MPa] 395 514 587 438 556 870 807 Elastic modulus at ?10? C. [MPa] 477 586 680 608 758 954 902 Elastic modulus at ?20? C. [MPa] 571 712 809 922 1169 1191 1134 Elastic modulus at ?30? C. [MPa] 736 885 1064 1345 1301 1334 1260 Percentage increase in elastic 262 231 244 656 368 253 213 modulus from room temperature to ?30? C. Charpy notched impact strength 107 104 102 175 139 117 114 at ?10? C. [kJ/m.sup.2] Charpy notched impact strength 110 112 114 15 122 118 116 at ?20? C. [kJ/m.sup.2] Charpy notched impact strength 120 120 124 9 25 113 121 at ?30? C. [kJ/m.sup.2] Colorability with 2% color 3 3 3 1 1 1 2 masterbatch 1 (*) Colorability with 2% color 3 3 3 1 1 1 2 masterbatch 2 (*) Formulations and properties of materials H-N Material H I J K L M N EB inv. Example/VB comp. EB EB EB VB EB EB EB example HP fraction [%] 53 53 57 60.5 62.5 72 60.5 Average molar weight of PTHF 1600 1700 1700 1000 1700 1700 1400 [Dalton] Poly THF 2000 OHN: 56.1 [g] 30.13 33.34 30.54 0 26.63 19.83 18.93 Poly THF 1000 OHN: 112.2 [g] 10.05 7.14 6.54 31.38 5.7 4.24 14.2 Lupranat MET [g] 44.84 44.53 46.9 52.25 50.2 55.95 49.92 Butanediol, 1,4- [g] 13.88 13.89 14.92 15.99 16.37 18.88 15.85 Density [g/cm.sup.3] 1.15 1.15 1.16 1.20 1.18 1.20 n.d. Hardness [Shore D] 58 57 62 75 66 74 n.d. Tensile strength [MPa] 42 43 43 65 44 51 n.d. Elongation at break [%] 330 360 310 380 260 180 n.d. Tear propagation resistance 168 126 155 220 183 238 n.d. [kN/m] Abrasion [mm.sup.3] 48 47 52 22 75 113 n.d. Elastic modulus at 20? C. [MPa] 550 561 803 774 1101 1597 n.d. Elastic modulus at 0? C. [MPa] 731 700 943 1370 1354 2000 n.d. Elastic modulus at ?10? C. [MPa] 783 816 1043 1841 1431 2256 n.d. Elastic modulus at ?20? C. [MPa] 940 927 1170 2171 1606 2525 n.d. Elastic modulus at ?30? C. [MPa] 1137 1286 1439 2642 1980 2835 n.d. Percentage increase in elastic 206 229 179 341 179 178 n.d. modulus from room temperature to ?30? C. Charpy notched impact 105 105 114 9 91 n.d. n.d. strength at ?10? C. [kJ/m.sup.2] Charpy notched impact 107 118 122 9 82 n.d. n.d. strength at ?20? C. [kJ/m.sup.2] Charpy notched impact 119 123 117 8 31 n.d. n.d. strength at ?30? C. [kJ/m.sup.2] Colorability with 2% color 3 3 5 1 5 5 1 masterbatch 1 Colorability with 2% color 3 3 5 1 5 5 1 masterbatch 2 n.d.not determined (*) Assessment of colorability: 1very good 2good 3satisfactory 4adequate 5inadequate

CITED LITERATURE

(7) WO 2007/118827A1 Kunststoffhandbuch, volume VII, edited by Vieweg and H?chtlen, Carl Hanser Verlag, Munich 1966 (p. 103-113) EP 0 922 552 A1 DE101 03 424 A1 WO 2006/072461 A1