FOAMS BASED ON THERMOPLASTIC ELASTOMERS

Abstract

The present invention relates to bead foams made of thermoplastic polyurethane and styrene polymer with a modulus of elasticity below 2700 MPa, to moldings produced therefrom, to processes for the production of the bead foams and moldings, and also to the use of the moldings 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.

Claims

1-15. (canceled)

16. A bead foam made of a composition (Z) comprising: from 60 to 95% by weight of a thermoplastic polyurethane as component I, and from 5 to 40% by weight of a styrene polymer as component II, wherein the styrene polymer has a modulus of elasticity below 2700 MPa, wherein the entirety of components I and II provides 100% by weight, and wherein the styrene polymer is high-impact polystyrene.

17. The bead foam of claim 16, wherein the bead foam is in the form of beads having an average diameter of between 0.2 and 20 mm.

18. A process for the production of a molded body made of the bead foam of claim 16, comprising: impregnating the composition with a blowing agent under pressure to form an impregnated composition; and decreasing a pressure to expand the impregnated composition.

19. A molded body made of bead foam, obtained by the process of claim 18.

20. A molded body made of the bead foam of claim 16, wherein the tensile strength of the molded body is above 600 kPa.

21. The molded body of claim 20, having an elongation at break of above 100%.

22. The molded body of claim 20, having a compressive stress at 10% compression of above 15 kPa.

23. The molded body of claim 20, wherein the density of the molded body is from 75 to 375 kg/m.sup.3.

24. The molded body of claim 20, wherein the rebound resilience of the molded body is above 55%.

25. The molded body of claim 20, wherein the molded body is at least one selected from the group consisting of an intermediate sole for a shoe, an insert for a shoe, and a cushioning element for a shoe, wherein the shoe is at least one selected from the group consisting of an outdoor shoe, a sports shoe, a sandal, a boot, and a safety shoe.

26. A process for the production of a molded body of claim 20, comprising: introducing the bead foam into an appropriate mold, and fusing the bead foam after the introducing.

27. A shoe comprising the molded body of claim 20.

28. A molded body comprising the bead foam of claim 16, wherein the molded body is a whole or a part of at least one selected from the group consisting of a shoe intermediate sole, a shoe insole, a shoe combisole, a cushioning element for a shoe, a bicycle saddle, a bicycle tire, a damping element, a cushioning, a mattress, an underlay, a grip, a protective film, a component in the automobile-interior sector, a component in the automobile-exterior sector, a ball, a sport equipment, and a floorcovering.

29. The molded body of claim 28, which is a whole or a part of at least one selected from the group consisting of a shoe intermediate sole, a shoe insole, a shoe combisole, and a cushioning element for a shoe.

Description

[0164] Illustrative embodiments of the present invention are listed below, but do not restrict the present invention. In particular, the present invention also encompasses embodiments which result from the dependencies stated below, therefore being combinations: [0165] 1. A bead foam made of a composition (Z) comprising [0166] a) from 60 to 95% by weight of thermoplastic polyurethane as component I [0167] b) from 5 to 40% by weight of the styrene polymer with a modulus of elasticity below 2700 MPa as component II,  where the entirety of components I and II provides 100% by weight. [0168] 2. The bead foam according to embodiment 1, comprising [0169] a) from 65 to 95% by weight of thermoplastic polyurethane as component I [0170] b) from 5 to 35% by weight of the styrene polymer as component II,  where the entirety of components I and II provides 100% by weight. [0171] 3. The bead foam according to embodiment 1, comprising [0172] a) from 80 to 85% by weight of thermoplastic polyurethane as component I [0173] b) from 15 to 20% by weight of [material II] as components II  where the entirety of components I and II provides 100% by weight. [0174] 4. The bead foam according to any of embodiments 1 to 3, where the styrene polymer is high-impact polystyrene (HIPS). [0175] 5. The bead foam according to any of embodiments 1 to 4, where the average diameter of the foam beads is between 0.2 and 20. [0176] 6. The bead foam according to any of embodiments 1 to 4, where the average diameter of the foam beads is from 0.5 to 15 mm. [0177] 7. A process for the production of a molded body made of bead foams according to any of embodiments 1 to 6, comprising [0178] i. provision of a composition (Z) of the invention; [0179] ii. impregnation of the composition with a blowing agent under pressure; [0180] iii. expansion of the composition by means of pressure decrease. [0181] 8. A molded body made of bead foam according to any of embodiments 1 to 6. [0182] 9. The molded body made of bead foam according to any of embodiments 1 to 6, wherein the tensile strength of the molded body is above 600 kPa. [0183] 10. The molded body according to embodiment 8 or 9, wherein elongation at break is above 100%. [0184] 11. The molded body according to embodiment 8, 9 or 10, wherein compressive stress at 10% compression is above 15 kPa. [0185] 12. The molded body according to any of embodiments 8 to 11, wherein the density of the molded body is from 75 to 375 kg/m.sup.3. [0186] 13. The molded body according to any of embodiments 8 to 12, wherein the density of the molded body is from 100 to 300 kg/m.sup.3. [0187] 14. The molded body according to any of embodiments 8 to 13, wherein the density of the molded body is from 150 to 200 kg/m.sup.3. [0188] 15. The molded body according to any of embodiments 8 to 14, wherein the rebound resilience of the molded body is above 55%. [0189] 16. The molded body according to any of embodiments 8 to 15, wherein the ratio of the density of the molding to the bulk density of the bead foam is from 1.5 to 2.5. [0190] 17. The molded body made of bead foam according to any of embodiments 8 to 16, wherein the ratio of the density of the molding to the bulk density of the bead foam is from 1.8 to 2.0. [0191] 18. The molded body according to any of embodiments 8 to 17, where the molded body is an intermediate sole for shoes. [0192] 19. The molded body according to any of embodiments 8 to 17, where the molded body is an insert for shoes. [0193] 20. The molded body according to any of embodiments 8 to 17, where the molded body is a cushioning element for shoes. [0194] 21. The molded body according to any of embodiments 8 to 17, where the shoe is an outdoor shoe, sports shoe, sandal, boot or safety shoe. [0195] 22. The molded body according to any of embodiments 8 to 17, where the shoe is a sports shoe. [0196] 23. A process for the production of a molded body according to any of embodiments 8 to 17 comprising [0197] (i) introduction of the foam beads into an appropriate mold, [0198] (ii) fusion of the foam beads from step (i). [0199] 24. The process according to claim 23, wherein the fusion in step (ii) is achieved in a closed mold. [0200] 25. The process according to claim 23 or 24, wherein the fusion in step (ii) is achieved by means of steam, hot-air or high-energy radiation. [0201] 26. A shoe comprising a molded body according to any of embodiments 8 to 17. [0202] 27. The shoe according to embodiment 26, wherein the shoe is an outdoor shoe, sports shoe, sandal, boot or safety shoe. [0203] 28. The shoe according to embodiment 26, wherein the shoe is a sports shoe. [0204] 29. The use of a bead foam according to any of embodiments 1 to 6 for the production of a molded body according to any of embodiments 8 to 17 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. [0205] 30. The use according to embodiment 29 for shoe intermediate soles, shoe insoles, shoe combisoles, or cushioning elements for shoes. [0206] 31. The use according to embodiment 30, where the shoe is a sports shoe.

[0207] The examples below serve to illustrate the invention, but are in no way restrictive in respect of the subject matter of the present invention.

Examples

[0208] The expanded beads made of thermoplastic polyurethane and of the impact-modified polystyrene were produced by using a twin-screw extruder with screw diameter 44 mm and length-to-diameter ratio 42 with attached melt pump, a diverter valve with screen changer, a pelletizing die and an underwater pelletization system. In accordance with processing guidelines, the thermoplastic polyurethane was dried for 3 h at 80° C. prior to use in order to obtain residual moisture content below 0.02% by weight. In order to prevent introduction of moisture via the impact-modified polystyrene, quantities used of which were likewise significant, this was likewise dried for 3 h at 80° C. to residual moisture content below 0.05% by weight. 0.6% by weight, based on the thermoplastic polyurethane used, of a thermoplastic polyurethane to which diphenylmethane 4,4′-diisocyanate with average functionality 2.05 had been admixed in a separate extrusion process was added to each example, alongside the two abovementioned components.

[0209] Thermoplastic polyurethane used was an ether-based TPU from BASF (Elastollan 1180 A) with a Shore hardness 80 A according to the data sheet. The impact-modified polystyrene used was Styrolution PS 485N from Ineos with modulus of elasticity 1650 MPa measured in the tensile test according to data sheet.

[0210] The thermoplastic polyurethane, the impact-modified polystyrene, and also the thermoplastic polyurethane to which diphenylmethane 4,4′-diisocyanates have been admixed were respectively metered separately into the intake of the twin-screw extruder by way of gravimetric metering devices.

[0211] Table 1 lists the proportions by weight of the thermoplastic polyurethane, inclusive of the thermoplastic polyurethane to which diphenylmethane 4,4′-diisocyanate had been admixed, and the impact-modified polystyrene.

TABLE-US-00001 TABLE 1 Proportions by weight of thermoplastic polyurethane and impact-modified polystyrene in the examples Elastollan 1180 A Styrolution PS 485N Example (E) [% by wt.] [% by wt.] E1 90 10 E2 95 5 E3 92.5 7.5 E4 90 10 E5 87.5 12.5 E6 85 15 E7 80 20

[0212] The materials were metered into the intake of the twin-screw extruder and then melted and mixed with one another. After mixing, a mixture of CO.sub.2 and N.sub.2 was added as blowing agent. During passage through the remainder of the length of the extruder, the blowing agent and the polymer melt were mixed with one another to form a homogeneous mixture. The total throughput of the extruder, including the TPU, the TPU, to which diphenylmethane 4,4′-diisocyanate with average functionality 2.05 had been added in a separate extrusion process, the impact-modified polystyrene and the blowing agents, was 80 kg/h.

[0213] A gear pump (GP) was then used to force the melt mixture by way of a diverter valve with screen changer (DV) into a pelletizing die (PD), and said mixture was chopped in the cutting chamber of the underwater pelletization system (UP) to give pellets and transported away by the temperature-controlled and pressurized water, and thus expanded. A centrifugal dryer was used to ensure separation of the expanded beads from the processed water.

[0214] Table 2 lists the plant-component temperatures used. Table 3 shows the quantities used of blowing agent (CO.sub.2 and N.sub.2), the quantities being adjusted in each case to give the lowest possible bulk density. The quantitative data for the blowing agents are based on the total throughput of polymer.

TABLE-US-00002 TABLE 2 Plant-component temperature data Temper- Temper- Temper- Temper- Water ature ature ature ature Water temper- range in range range range pressure ature extruder of GP of DV of PD in UP in UP (° C.) (° C.) (° C.) (° C.) (bar) (° C.). E1 220-170 170 170 220 15 40 E2 220-170 155 155 220 15 40 E3 220-170 155 155 220 15 40 E4 220-170 155 155 220 15 40 E5 220-170 155 155 220 15 40 E6 220-170 155 155 220 15 40 E7 220-170 155 155 220 15 40

TABLE-US-00003 TABLE 3 Quantities added of blowing agents, based on total throughput of polymer CO.sub.2 N.sub.2 [% by wt.] [% by wt.] E1 2.2 0.1 E2 1.8 0.1 E3 1.9 0.1 E4 2.0 0.1 E5 2.1 0.1 E6 2.2 0.1 E7 2.45 0.1

[0215] Table 4 lists the bulk densities of the expanded pellets resulting from each of the examples.

TABLE-US-00004 TABLE 4 Bulk density achieved for expanded beads after about 3 h of storage time Bulk density (g/l) E1 128 ± 4 E2 165 ± 3 E3 158 ± 7 E4 162 ± 5 E5 166 ± 5 E6 160 ± 4 E7 165 ± 6

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