Combination foam
The combination foam comprises a matrix composed of polyurethane foam and foamed particles of thermoplastic polyurethane comprised therein, where matrix and particles are each made up of polyol components and polyisocyanate components, wherein at least 50% by weight of the basic building blocks forming the polyol component of the matrix and particles are identical and at least 50% by weight of the basic building blocks forming the polyisocyanate component of the matrix and particles are identical.
1. A combination foam, comprising:
a matrix comprising polyurethane foam; and
foamed particles of thermoplastic polyurethane comprised therein,
wherein the matrix and the particles each comprises polyol components and polyisocyanate components, wherein at least 50% by weight of building blocks forming the polyol component of the matrix and particles are identical and at least 50% by weight of building blocks forming the polyisocyanate component of the matrix and particles are identical, whereby the matrix is completely open-cell and the foamed particles in the matrix are completely closed-cell.
2. The combination foam according to claim 1 , wherein at least 60% by weight of the building blocks forming the polyol component of the matrix and particles are identical and at least 60% by weight of the building blocks forming the polyisocyanate component of the matrix and particles are identical.
3. The combination foam according to claim 2 , wherein at least 65% by weight of the building blocks forming the polyol component of the matrix and particles are identical and at least 85% by weight of the building blocks forming the polyisocyanate component of the matrix and particles are identical.
4. The combination foam according to claim 1 , wherein the foamed particles have a diameter of from 0.1 mm to 10 cm, and are spherical or ellipsoidal.
5. The combination foam according to claim 1 , wherein the foamed particles have a density of from 0.005 to 0.50 g/cm 3 .
6. The combination foam according to claim 1 , wherein the thermoplastic polyurethane of the foamed particles and the polyurethane foam of the matrix comprise polytetrahydrofuran having a number average molecular weight of from 600 to 2500 g/mol.
7. The combination foam according to claim 1 , wherein the thermoplastic polyurethane of the foamed particles and the polyurethane foam of the matrix comprise polyester alcohol having a number average molecular weight of from 500 to 2500 g/mol.
8. The combination foam according to claim 1 , wherein the matrix is a foam having a density of from 0.03 to 0.8 g/cm 3 .
9. The combination foam according to claim 1 , wherein the matrix and the particles are present in a weight ratio of from 0.1 to 10:1 in the combination foam.
10. The combination foam according to claim 1 , wherein the combination foam is suitable as shoe soles, bicycle saddles, upholstery, in components in automobile interiors and exteriors, in balls and sports equipment or as floor covering.
11. A process for producing the combination foam according to claim 1 , comprising reacting the polyol components and polyisocyanate components to form the matrix comprising polyurethane foam and optionally chain extenders, crosslinkers, catalysts, blowing agents, further additives or mixtures thereof, in the presence of the foaming or foamed particles of thermoplastic polyurethane.
12. The process according to claim 11 , wherein no external blowing agent is employed.
13. The process according to claim 11 , comprising:
first preparing an isocyanate prepolymer having an NCO content of from 1 to 20% by weight from polyisocyanate components and polyol components of the matrix;
optionally subsequently mixing at least one chain extender, crosslinker, catalyst, further additive or a mixture thereof and the isocyanate prepolymer with the foamed particles of the thermoplastic polyurethane to form a composite; and then
curing the composite with water.