Hybrid systems consisting of foamed thermoplastic elastomers and polyurethanes

Abstract

The present invention relates to a hybrid material comprising a matrix of polyurethane and foamed particles of thermoplastic polyurethane comprised therein and also a process for producing such hybrid materials and the use of these hybrid materials as bicycle saddles, upholstery and shoe soles.

1 : A hybrid material comprising a matrix of polyurethane and foamed particles of thermoplastic polyurethane, wherein the foamed particles have a closed surface skin. 
   
   
       2 : The hybrid material according to  claim 1 , wherein the foamed particles have a diameter of from 0.1 mm to 10 cm and are spherical or ellipsoidal. 
   
   
       3 : The hybrid material according to  claim 2 , wherein the foamed particles have a diameter of from 0.5 mm to 5 cm. 
   
   
       4 : The hybrid material according to  claim 1 , wherein the foamed particles have a density of from 0.005 to 0.50 g/cm 3 . 
   
   
       5 : The hybrid material according to  claim 1 , wherein the thermoplastic polyurethane of the foamed particles comprises polytetrahydrofuran having a number average molecular weight of from 600 to 2500 g/mol. 
   
   
       6 : The hybrid material according to  claim 1 , wherein the thermoplastic polyurethane of the foamed particles comprises polyester alcohol having a number average molecular weight of from 500 to 2500 g/mol. 
   
   
       7 : The hybrid material according to  claim 1 , wherein the matrix of polyurethane is a foam, a compact elastomeric system, or a gel. 
   
   
       8 : The hybrid material according to  claim 7 , wherein the matrix is a compact material and the weight ratio of matrix to foamed particles is from 1:1 to 1:20. 
   
   
       9 : The hybrid material according to  claim 1 , wherein the matrix is a foam having a density of from 0.03 to 0.8 g/cm 3 . 
   
   
       10 : The hybrid material according to  claim 1 , wherein a tear propagation resistance is greater than 2.5 N/mm at an average density of the hybrid material of from 0.4 to 0.5 g/cm 3 , greater than 2.2 N/mm at an average density of the hybrid material of from 0.3 to <0.4 g/cm 3 , greater than 2.0 N/mm at an average density of the hybrid material of from 0.2 to <0.3 g/cm 3  and greater than 1.0 N/mm at an average density of the hybrid material of from 0.1 to <0.2 g/cm 3 . 
   
   
       11 : A shoe sole, bicycle saddle, or upholstery comprising the hybrid material according to  claim 1 . 
   
   
       12 : A floor covering comprising the hybrid material according to  claim 7 . 
   
   
       13 : A process for producing a hybrid material comprising a matrix of polyurethane and foamed particles of thermoplastic polyurethane, which comprises:
 mixing   a) polyisocyanates with   b) compounds having hydrogen atoms which are reactive toward isocyanates,   c) expandable particles (c′) of thermoplastic polyurethane which comprise blowing agents in dispersed or dissolved form   and, optionally,   d) chain extenders and/or crosslinkers,   e) catalysts,   f) blowing agents and   g) further additives,   and reacting the mixture to form the hybrid material, thereby expanding the expandable particles (c′) wherein the foamed particles have a closed surface skin.   
   
   
       14 : The process for producing the hybrid material according to  claim 13 , wherein the expandable particles (c′) have a Shore hardness of from A44 to A84. 
   
   
       15 : The process for producing a hybrid material according to  claim 13 , wherein the melting range of the expandable particles (c′) in a DSC measurement at a heating rate of 20 K/min commences below 130° C. and the thermoplastic polyurethane has a melt flow rate (MFR) of not more than 250 g/10 min at 190° C. under a weight of 21.6 kg in accordance with DIN EN ISO 1133. 
   
   
       16 : The process for producing a hybrid material according to  claim 13 , wherein the expandable particles (c′) have an average diameter of from 0.1 to 10 mm. 
   
   
       17 : The process for producing a hybrid material according to  claim 13 , wherein the expandable particles (c′) have a content of blowing agent, based on the total weight of the particles (c′), of from 1 to 50% by weight. 
   
   
       18 : The process for producing a hybrid material according to  claim 13 , wherein the reaction is carried out at a temperature of the reaction mixture of from 100 to 140° C. 
   
   
       19 : A process for producing a hybrid material comprising a matrix of polyurethane and foamed particles of thermoplastic polyurethane comprised therein, which comprises:
 mixing   a) polyisocyanates with   b) compounds having hydrogen atoms which are reactive toward isocyanates,   c) expanded particles (c″) of thermoplastic polyurethane and, if appropriate,   d) chain extenders and/or crosslinkers,   e) catalysts,   f) blowing agents and   g) further additives,   and reacting the mixture to form the hybrid material, with the foamed particles having a closed surface skin.   
   
   
       20 : The process for producing a hybrid material according to  claim 19 , wherein the expanded particles (c″) have a diameter of from 0.1 mm to 10 cm, and are spherical or ellipsoidal. 
   
   
       21 : The process for producing a hybrid material according to  claim 19 , wherein the expanded particles have a density of from 0.005 to 0.50 g/cm 3  and have a compact outer skin. 
   
   
       22 : The process according to  claim 19 , wherein no blowing agent is used. 
   
   
       23 : The process according to  claim 22 , wherein an isocyanate prepolymer having an NCO content of from 1 to 20% by weight is firstly prepared from polyisocyanates a) and compounds having hydrogen atoms which are reactive toward isocyanates b) and, optionally, chain extenders and/or crosslinkers d), catalysts e) and further additives f), and the isocyanate prepolymer is subsequently mixed with the expanded particles (c″) of thermoplastic polyurethane and the composite is allowed to cure by action of water. 
   
   
       24 : The process according to  claim 23 , wherein the weight ratio of the components (a), (b) and (d)-(g) to component (c″) is from 1:1 to 1:20.