Foams based on thermoplastic elastomers
A bead foam is made of thermoplastic polyurethane, a styrene polymer, and an impact modifier. Moldings can be produced from the bead foam and processes for the production of the bead foams and moldings can be utilized. The moldings can be used for shoe intermediate soles, shoe insoles, shoe combisoles, cushioning elements for shoes, bicycle saddles, bicycle tires, damping elements, cushioning, mattresses, underlays, grips, protective films, in components in the automobile-interior sector or automobile-exterior sector, balls and sports equipment, or as floorcovering.
1. A bead foam, made of a composition (Z) comprising:
a. from 60 to 94% by weight of thermoplastic polyurethane as component I,
b. from 5 to 30% by weight of a styrene polymer as component II, wherein the styrene polymer is an atactic polystyrene,
c. from 1 to 10% by weight of an impact modifier as component III, wherein the impact modifier is an impact-resistant polystyrene (HIPS) and,
wherein the entirety of components I, II, and III provides 100% by weight.
2. The bead foam according to claim 1 , wherein an average diameter of the bead foam is from 0.5 to 20 mm.
3. The bead foam according to claim 1 , wherein the composition (Z) comprises from 80 to 94% by weight of the thermoplastic polyurethane as component I.
4. The bead foam according to claim 1 , wherein the composition (Z) comprises from 5 to 10% by weight of the styrene polymer as component II.
5. A process for the production of the bead foam according to claim 1 , the process comprising:
i. impregnating the composition (Z) with a blowing agent under pressure; and
ii. expanding the composition by means of pressure decrease.
6. A molded body, comprising:
the bead foam according to claim 1 .
7. The molded body according to claim 6 , wherein a tensile strength of the molded body is above 600 kPa.
8. The molded body according to claim 6 , wherein elongation at break is above 100%.
9. The molded body according to claim 6 , wherein compressive stress at 10% compression is above 15 kPa.
10. The molded body according to claim 6 , wherein a density of the molded body is from 75 to 375 kg/m 3 .
11. The molded body according to claim 6 , wherein a rebound resilience of the molded body is above 55%.
12. The molded body according to claim 6 , wherein the molded body is an intermediate sole, an insert, or a cushioning element for a shoe,
wherein the shoe is an outdoor shoe, a sports shoe, a sandal, a boot, or a safety shoe.
13. A process for the production of the molded body according to claim 6 , the process comprising:
(i) introducing the bead foam into an appropriate mold, and
(ii) fusing the bead foam from (i).
14. A shoe, comprising the molded body according to claim 6 .
15. A bead foam, comprising a composition (Z) which comprises:
a. from 80 to 94% by weight of thermoplastic polyurethane as component I,
b. from 5 to 10% by weight of a styrene polymer as component II, wherein the styrene polymer is an atactic polystyrene, and
c. from 1 to 10% by weight of an impact modifier as component III, wherein the impact modifier is an impact-resistant polystyrene (HIPS), and
wherein the entirety of components I, II, and III provides 100% by weight.
16. The bead foam according to claim 15 , wherein the composition (Z) comprises:
a. 91% by weight of thermoplastic polyurethane as component I,
b. 5% by weight of the styrene polymer as component II, wherein the styrene polymer is an atactic polystyrene, and
c. 4% by weight of the impact modifier as component III, wherein the impact modifier is an impact-resistant polystyrene (HIPS) and
wherein the entirety of components I, II, and III provides 100% by weight.
17. The bead foam according to claim 4 , wherein a tensile modulus of elasticity of the styrene polymer as component II is above 2500 MPa, according to DIN EN ISO 527 1/2, June 2012.
18. The bead foam according to claim 1 , wherein a tensile modulus of elasticity of the impact modifier as component III is below 2700 MPa, according to DIN EN ISO 527-1/2, June 2012.