Thermoplastic polyurethane

Abstract

The present invention relates to a polyurethane, in particular a thermoplastic polyurethane, obtainable or obtained by reacting at least the components (i) to (ii): (i) a polyisocyanate composition; (ii) a polyol composition, comprising (ii.1) at least one polyester diol or polyether diol having a number-average molecular weight in the range from 500 to 3000 g/mol, (ii.2) at least one polysiloxane having two terminal isocyanate-reactive functionalities selected from the group consisting of thio group, hydroxyl group and amino group. The invention additionally relates to a process for preparing this polyurethane, to the use thereof, to a molded body comprising the polyurethane. Furthermore, the invention relates to foam beads based on polyurethane, obtained or obtainable from the polyurethane, to a process for producing foam beads and also to bead foams and to the use thereof.

Claims

1. A polyurethane, obtained by reacting at least components (i) to (iii): (i) a polyisocyanate composition; (ii) a polyol composition, comprising (ii.1) a polyester diol or polyether diol having a number-average molecular weight in a range from 500 to 3000 g/mol, and (ii.2) a polysiloxane of formula I: ##STR00029## where n is an integer in a range from 1 to 250, A and B are independently selected from the group of the C1-C20-alkyl groups.sub.; where X.sub.1 of the polysiloxane as per (ii.2) is a (CH.sub.2—CH.sub.2—O).sub.m group, a (CH.sub.2—CH.sub.2—CH.sub.2—O).sub.m group, or a (CH.sub.2—CHCH.sub.3—O).sub.m group, X.sub.2 of the polysiloxane as per (ii.2) is a (CH.sub.2—CHCH.sub.3—O).sub.m group, an (O—CH.sub.2—CH.sub.2).sub.m group, or an (O—CH.sub.2—CH.sub.2—CH.sub.2).sub.m group, where m for X.sub.1 and X.sub.2 in each case independently is an integer in a range from 2 to 20; and Y.sub.1 and Y.sub.2 are both a hydroxyl group; wherein the polysiloxane as per (ii.2) is present in a proportion in a range from 5% to 20% by weight, based on a total weight of all of components (ii.1) and (ii.2); and (iii) a chain extender composition.

2. The polyurethane according to claim 1, having a melt mass-flow rate, determined according to DIN EN ISO 1133 in the March 2012 version and measured at a temperatein a range from 190 to 220° C. and at a mass in a range from 1 to 30 kg, in a range from 20 to 350 g/10 min.

3. The polyurethane according to claim 1, wherein n of the polysiloxane as per (ii.2) is an integer in a range from 3 to 50 or in a range from 100 to 240.

4. The polyurethane according to claim 1, wherein A and B of the polysiloxane as per) are independently selected from the group of the C.sub.1- to C5-alkyl groups.

5. The polyurethane according to claim 1, wherein the polysiloxane as per (ii.2) is present in a proportion in a range from 7% to 20% by weight, based on a total weight of all of components (ii.1) and (ii.2).

6. The polyurethane according to claim 1 wherein the polyurethane has a hard segment content in a range from 10% to 50% by weight, based on a total weight of all of components (i), (ii), (iii).

7. The polyurethane according to claim 1, wherein the polyurethane has a hardness in a range from Shore 30A to 98A or in a range from Shore 40D to 64D.

8. The polyurethane according to claim 1, obtained by reacting at least components (i) to (iii): (i) a diisocyanate composition comprising at least 4,4'-MDI or HDI; (ii) a polyol composition, comprising (ii.1) a polyether diol or a polyester diol, wherein the polyether diol or polyester diol has a number-average molecular weight in a range from 500 to 3000 g/mol, and (ii.2) a polysiloxane of formula Ia: ##STR00030## where n is an integer in a range from 10 to 20, A and B are both methyl groups; X.sub.1 is a (CH.sub.2—CH.sub.2—O).sub.m group, X.sub.2 is an (O—CH.sub.2—CH.sub.2).sub.m group, where m for X.sub.1 and X.sub.2 in each case independently is an integer in a range from 3 to 15; (iii) a chain extender composition comprising at least one diol or diamine selected from the group consisting of butane-1,4-diol, hexane-1,6-diol, ethane-1,2-diol and 2,4-diamino-3,5-di(methylthio)toluene.

9. A process for preparing a polyurethane according to claim 1, the process comprising reacting components (i) to (iii): (i) a polyisocyanate composition; (ii) a polyol composition, comprising (ii.1) a polyester diol or polyether diol having a number-average molecular weight in a. range from 500 to 3000 g/mol, and (ii.2) a polysiloxane of formula I ##STR00031## where n is an integer in a range from 1 to 250, A and B are independently selected from the group of the C1-C20-alkyl groups, where X.sub.1 of the polysiloxane as per (ii.2) is a (CH.sub.2—CH.sub.2—O).sub.m group, a (CH.sub.2—CH.sub.2—CH.sub.2—O).sub.m group, or a (CH.sub.2—CHCH.sub.3—O).sub.m group, X2 of the polysiloxane as per (ii.2) is an (O—CHCH.sub.3—CH.sub.2).sub.m group, an (O—CH.sub.2—CH.sub.2).sub.m group, or an (O—CH.sub.2—CH.sub.2—CH.sub.2).sub.m group, where m for X.sub.1 and X.sub.2 in each case independently is an integer in a range from 2 to 20; and Y.sub.1 and Y.sub.2 are both a hydroxyl group; and (iii) a chain extender composition.

10. A molded body, an injection-molded product, an extrusion product, or a film, comprising the polyurethane according to claim 1.

11. An article, comprising the polyurethane according to claim 1, wherein the article is a consumer article.

12. An article, comprising a polyurethane obtained by the process according to claim 9.

13. A foam bead based on polyurethane, obtained from a polyurethane according to claim 1, wherein the polyurethane is obtained by reacting at least components (i) to (ii): (i) a polyisocyanate composition; and (ii) a polyol composition, comprising (ii.1) a polyester diol or polyether diol aving a number-average molecular weight in a range from 500 to 3000 g/mol, and (ii.2) a polysiloxane having two terminal hydroxyl groups.

14. The foam head based on polyurethane according to claim 13, wherein the polyurethane is obtained by reacting at least components (i) to (iii): (i) a polyisocyanate composition; (ii) a polyol composition, comprising (ii.1) a polyester diol or polyether diol having a number-average molecular weight in a range from 500 to 3000 g/mol, and (ii.2) a polysiloxane having two terminal isocyanate-reactive functionalities selected from the group consisting of a thio group, a hydroxyl group and an amino group; and (iii) a chain extender composition.

15. The foam bead based on polyurethane according to claim 13, wherein the polyurethane is obtained by reacting at least components (i) to (ii): (i) a polyisocyanate composition; (ii) a polyol composition, comprising (ii.1) a polyester diol or polyether diol having a number-average molecular weight in a range from 500 to 3000 g/mol, and (ii.2) a polysiloxane of formula I: ##STR00032## where n is an integer in a range from 1 to 250, A and B are independently selected from the group of the C1-C20-alkyl groups; X.sub.1 is selected from the group consisting of (CH.sub.2—CH.sub.2—O).sub.m group, (CH.sub.2—CH.sub.2—CH.sub.2—O).sub.m group, (CH.sub.2).sub.m—O group, and (CH.sub.2).sub.m group, X.sub.2 is selected from the group consisting of (O—CH.sub.2—CH.sub.2).sub.m group, (O—CHCH.sub.3—CH.sub.2).sub.m group, (O—CH.sub.2—CH.sub.2—CH.sub.2).sub.m group, O—(CH.sub.2).sub.m and —(CH.sub.2).sub.m group, where in for X.sub.1 and X.sub.2 in each case independently is an integer in a range from 2 to 20; and Y.sub.1, Y.sub.2 are hydroxyl groups; and (iii) a chain extender composition.

16. The foam bead based on polyurethane according to claim 13, wherein n of the polysiloxane as per (ii.2) integer in a range from 3 to 50 or in a range from 100 to 240.

17. The foam bead based on polyurethane according to claim 13, wherein A and B of the polysiloxane as per (ii.2) are independently selected from the group of the C1- to C5-alkyl groups.

18. The foam bead based on polyurethane according to claim 13. wherein the polyurethane has a hard segment content in a range from 10% to 50% by weight based on a total weight of all of components (i), (ii), (iii).

19. The foam bead based on polyurethane according to claim 13. wherein the polyurethane has a hardness in a range from Shore 30AA to 98A or in a range from Shore 40D to 64D.

20. The foam bead based on polyurethane according to claim 13, wherein the poly.sup.-urethane is obtained by reacting at least components (i) to (iii): (i) a diisocyanate composition comprising at least 4,4′-MDI or HDI; (ii) a polyol composition, comprising (ii.1) a polyether diol or a polyester diol, wherein the polyether diol or polyester diol has a number-average molecular weight in a range from 500 to 3000 g/mol, and (ii.2) a polysiloxane of formula Ia.: ##STR00033## where n is an integer in a range from 10 to 20, A and B are both methyl groups; X.sub.1 is (CH.sub.2—CH.sub.2—O—).sub.m group. X.sub.2 is an (O—CH.sub.2—CH.sub.2).sub.m group, where m for X.sub.1 and X.sub.2 in each case independently is an integer in a range from 3 to 15, (iii) a chain extender composition comprising at least one diol or diamine selected from the group consisting of butane-1,4-diol, hexane-1,6-diol, ethane-1,2-diol and 2,4-diamino-3,5-di(methylthio)toluene.

21. The foam bead according to claim 13, wherein the polyurethane has a hardness in a range from Shore 30A to 98A or in a range from Shore 40D to 64D.

22. A process for producing the foam beads according to claim 13, the process comprising: melting the polyurethane, thereby obtaining the melted polyurethane, mixing the melted polyurethane with a blowing agent, thereby forming a blowing agent-containing melt, and pelletizing the blowing agent-containing melt while foaming at a pressure in a range front 1 to 15 bar.

23. A process for producing the foam beads according to claim 13, the process comprising: expanding the polyurethane in a presence of a blowing agent at a pressure in a range from 1 to 15 bar.

24. A bead foam obtained by fusing the foam bead according to claim 13 by means of water vapor or irradiation with electromagnetic radiation.

25. A bead foam obtained by adhesively bonding the foam beads according to claim 13.

26. An article, comprising the foam bead according to claim 13 wherein the article is suitable for applications in fields of sport, clothing, construction, automobiles, and electronics.

27. An article, comprising the foam bead according to claim 13, wherein the article is selected from the group consisting of consumer articles.

Description

EXAMPLES

1. Chemicals

(1) TABLE-US-00001 Name Chemical name Isocyanate 1 diphenylmethane 4,4′-diisocyanate (4,4′-MDI) Isocyanate 2 hexamethylene 1,6-diisocyanate (HDI) Chain extender 1 butane-1,4-diol (BDO) Chain extender 2 hexane-1,6-diol (1,6-HDO) Chain extender 3 ethane-1,2-diol (MEG) Chain extender 4 aromatic diamine (>95% by weight 2,4-diamino-3,5- di(methylthio)toluene) Antioxidant 1 pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4- hydroxyphenyl]propionate Antioxidant 2 N,N′-1,6-hexanediylbis[3,5-bis(1,1-dimethylethyl)-4- hydroxybenzenepropanamide Antioxidant 3 mixture of antioxidant 1 and antioxidant 2 in a ratio of 1:1 Antioxidant 3 mixture of antioxidant 1 and antioxidant 2 Polyol 1 polytetramethylene ether glycol (PTHF) having an OH number in the range from 109.5-115.1 mg KOH/g Polyol 2 polyester diol having a hydroxyl number of 56 mg KOH/g formed from adipic acid, butane-1,4-diol and hexane-1,6-diol; number-average molecular weight M.sub.n: 2000 g/mol (ADS/BDO/HDO) Hydrolysis polymer based on carbodiimide and polyglycol ether stabilizer Plasticizer tributyl O-acetylcitrate Antiblocking ethylenebisstearamide agent Catalyst 1 Kosmos ® 29 tin catalyst from Evonik Si polyol 1 difunctional polyol with 59% PDMS and 41% EO content and having an OH number of 62 mg KOH/g Si polyol 2 difunctional polyol with 55% PDMS and 45% EO content and having an OH number of 57 mg KOH/g Si polyol 3 difunctional polyol with 72% PDMS and 28% EO content and having an OH number of 65 mg KOH/g PDMS: polydimethylsiloxane EO: ethylene oxide

2. Measurement Methods

(2) Tensile strength: DIN 53504

(3) Elongation at break: DIN 53504

(4) Tear strength: DIN ISO 34-1 Bb

(5) Tear propagation resistance: DIN ISO 34-1 Bb

(6) Shore hardness: DIN ISO 7619-1

(7) Abrasion determination: DIN ISO 4649

(8) Hot air resistance: DIN 53508

(9) Melt

(10) mass-flow rate (MFR): DIN EN ISO 1133 (March 2012 version)

(11) The hard segment content (hard phase content) was determined according to the formula from WO 2010/076224 A1/U.S. Pat. No. 9,097,835 B2:

(12) $\mathrm{Hard}\mathrm{phase}\mathrm{content}=\left\{\underset{x=1}{\overset{k}{.Math.}}\left[{\left(m_{\mathrm{KVx}}/M_{\mathrm{KVx}}\right)}^{*}{M}_{\mathrm{iso}}+m_{\mathrm{KVx}}\right]\right\}/m_{\mathrm{ges}}$
having the following definitions:

(13) Mkv.sub.x: molar mass of the chain extender x in g/mol

(14) mKV.sub.x: mass of the chain extender x in g

(15) M.sub.Is0: molar mass of the isocyanate used in g/mol

(16) m.sub.ges: total mass of all starting materials in g

(17) k: number of chain extenders.

3. Example 1—Preparation of an SI-Based Thermoplastic Polyurethane (TPU) with Aromatic Isocyanate

(18) 660 g of polyol 1 and 440 g of Si polyol 3 together with 72.28 g of chain extender 1 were weighed into a 2 l tin can and briefly blanketed with nitrogen. The can was sealed with a suitable lid and heated to approx. 90° C. in a heating cabinet. The liquid components in the can were mixed on a lab jack by means of a propeller stirrer. 8.1 g of antioxidant 1 and 8.1 g of antioxidant 2 was subsequently added and the mixture was stirred. 433.61 g of isocyanate 1 were added at 80° C. The overall formulation is shown in table 1. The isocyanate 1 had a temperature of 45° C. Mixing was effected by means of a propeller stirrer at 200 rpm. Upon reaching 110° C., the reaction mixture was poured into a Teflon dish. The Teflon dish was situated on a heating stage at 125° C. After 10 min, the solid slab was removed from the heating stage and subsequently heat-treated for 24 h in a heating cabinet at 80° C. The cooled slab was comminuted in a cutting mill. The resulting pellets were dried at 110° C. for 3 h. 2 mm and 6 mm test specimens were produced by means of injection molding processes and used in accordance with the requirements of the respective DIN standard.

4. Examples 2 to 4—Preparation of Si-Based TPUs with Aromatic Isocyanate

(19) Further Si-based TPUs with aromatic isocyanate were produced analogously to the procedure of example 1, with the individual components being used in the amounts reported in table 1 (formulations).

(20) TABLE-US-00002 TABLE 1 Formulations for example 1 and examples 2 to 4 Example 1 Example 2 Example 3 Example 4 Polyol 1 660.00 g 950.00 g 900.00 g 880.00 g Si polyol 3 440.00 g 50.00 g 100.00 g 220.00 g Chain 72.28 g 67.82 g 67.52 g 73.61 g extender 1 Isocyanate 1 433.61 g 439.01 g 432.60 g 461.78 g Antioxidant 1 8.11 g 7.61 g 7.58 g 8.26 g Antioxidant 2 8.11 g 7.61 g 7.58 g 8.26 g

5. Determination of the Mechanical Properties of SI-Based TPUs with Aromatic Isocyanate

(21) The tensile strength, the elongation at break and the Shore hardness were measured, and the hard segment content and the abrasion determined, for the test specimens according to example 1 and examples 2, 3 and 4. Table 2 below shows the results of the tests.

(22) TABLE-US-00003 TABLE 2 Results of the mechanical investigations for the Si-based TPUs with aromatic isocyanate according to example 1 and examples 2, 3 and 4 MFR Hard segment Tensile (190° C./21.6 kg) Si polyol 3 content strength [g/10 min] Example 1 40% by 17% by not injection- flows through weight weight moldable Example 2 5% by 17% by >35 MPa 40   weight weight Example 3 10% by 17% by >35 MPa 80.4 weight weight Example 4 20% by 17% by >15 MPa flows through weight weight Elongation at Tear Shore hardness break strength (Shore A) Abrasion Example 1 not injection- not injection- not injection- not injection- moldable moldable moldable moldable Example 2 >500% >40 kN/m <75A <15 mm.sup.3 Example 3 >500% >40 kN/m <75A <15 mm.sup.3 Example 4 >500% >35 kN/m <75A <15 mm.sup.3

(23) It has surprisingly been found that, for an Si-based TPU having a content of Si polyol, in particular Si polyol 3, in the range from 5-30% by weight, in particular from 5-20% by weight, there was a significant improvement in the mechanical properties, in particular the tensile strength, elongation at break and tear strength, in comparison to an Si-based TPU having a content of 40% by weight. The abrasion was below 15 mm.sup.3 for all examples; this is a surprising improvement over standard TPUs not comprising any polysiloxane and also having a Shore A hardness of 70.

6. Example 5—Preparation of an SI-Based TPU with Aliphatic Isocyanate

(24) An Si-based TPU having a content of 40% by weight of Si polyol 3 was produced according to the procedure from example 1, the amounts of the components used being shown in table 3. Instead of the aromatic isocyanate 1 from comparative example 1, the aliphatic isocyanate 2 was used. Production of the test specimens was not possible since the TPU could not be processed by means of injection molding processes.

7. Examples 6 to 8—Preparation of SI-Based TPUs with Aliphatic Isocyanate

(25) Si-based TPUs having a content of Si polyol 3 in the range from 5% to 20% by weight were produced according to the procedure for example 1, the amounts of the components used being shown in table 3. Instead of the aromatic isocyanate 1 from example 1, the aliphatic isocyanate 2 was used. 2 mm and 6 mm test specimens were produced by means of injection molding processes according to the procedure from comparative example 1.

(26) TABLE-US-00004 TABLE 3 Formulations for example 5 and examples 6 to 8 Example 5 Example 6 Example 7 Example 8 Polyol 1 600.00 g 950.00 g 900.00 g 800.00 g Si polyol 3 400.00 g 50.00 g 100.00 g 200.00 g Chain 96.51 g 98.76 g 98.45 g 97.81 g extender 2 Isocyanate 2 279.21 g 309.04 g 304.85 g 296.47 g Catalyst 1 in 688 μl 704 μl 702 μl 697 μl 50% dioctyl adipate(DOA) Antioxidant 1 6.95 g 7.12 g 7.58 g 8.26 g Antioxidant 2 6.95 g 7.12 g 7.58 g 8.26 g

8. Determination of the Mechanical Properties of SI-Based TPUs with Aliphatic Isocyanate

(27) The tensile strength, the elongation at break, tear strength and Shore hardness were measured and the hard segment content determined for the test specimens according to example 5 and examples 6 to 8. Table 4 below shows the results of the tests.

(28) TABLE-US-00005 TABLE 4 Results of the mechanical investigations for the Si-based TPUs with aliphatic isocyanate of example 5 and examples 6 to 8. Hard segment MFR Si polyol 3 content Tensile (190° C./3.8 kg) [% by weight] [% by weight] strength [g/10 min] Example 5 40 17 (not n.m. 214.7 injection- moldable) Example 6 5 17 >20 MPa 28.8 Example 7 10 17 >20 MPa 54.07 Example 8 20 17 >15 MPa 116.98 Elongation at Shore hardness break Tear strength (Shore A) Example 5 n.m. n.m. n.m. Example 6 >500% >30 kN/m <90A Example 7 >500% >30 kN/m <90A Example 8 >500% >30 kN/m <90A n.m.: not measurable

(29) The Si-based TPUs with aliphatic isocyanate had, for an Si polyol content in the range from 1% to 30% by weight, preferably in the range from 5% to 20% by weight, improved tensile strength of in each case >15 MPa and a tear strength of >30 kN/m.

9. Comparative Example 1—Preparation of a TPU with Aromatic Isocyanate without SI Polyol

(30) A TPU without Si polyol was produced according to the procedure from example 1, the amounts of the components used being shown in table 5. 2 mm and 6 mm test specimens were produced by means of injection molding processes according to the procedure from example 1.

10. Examples 9 and 10—Preparation of Si-Based TPUs with Aromatic Isocyanates and Various Si Polyols

(31) Si-based TPUs having a content of Si polyol 2 (example 7, 10% by weight) or Si polyol 1 (example 8, 20% by weight) in the range from 10% to 20% by weight were produced according to the procedure from comparative example 1, the amounts of the components used being shown in table 5. 2 mm and 6 mm test specimens were produced by means of injection molding processes according to the procedure from example 1.

(32) TABLE-US-00006 TABLE 5 Formulations for comparative example 1 and examples 9 and 10 Comparative example 1 Example 9 Example 10 Polyol 2 1000.00 g 720.00 g 640.00 g Si polyol — 2 1 Amount of Si 0.00 g 80.00 g 160.00 g polyol Chain extender 1 164.3 g 164.28 g 164.62 g Isocyanate 1 560.00 g 560.0 g 560.0 g Hydrolysis 6.40 g 6.4 g 6.4 g stabilizer

11. Determination of the Thermal Stability of Si-Based TPUs with Aromatic Isocyanate (Long-Term Test)

(33) The test specimens of comparative example 1 and examples 9 and 10 were subjected to long-term hot air aging tests and tested for their resistance to hot air. To this end, all test specimens were stored in air at 165° C. for 3000 hours, the elongation at break was determined prior to this and afterwards. The results are shown in table 6.

(34) TABLE-US-00007 TABLE 6 Elongation at break values for comparative example 1 and examples 9 and 10, in each case before and after thermal aging (long-term test) Shore hardness Elongation Elongation MFR (Shore A) at break be- at break (220° C./ before ther- fore ther- after ther- 2.16 kg) mal aging mal aging mal aging [g/10 min] Comparative 95A >500% test specimen 7.13 example 1 melted Example 9 95A >500% >300% 65.7 Example 10 95A >500% >300% 103.5

(35) It could be observed that thermal aging for the test specimen of comparative example 1 resulted in deformation and that after 2000 hours of storage at 165° C. elongation at break had fallen below 50%. In contrast to this, the test specimens of examples 9 and 10, which both comprised 10% to 20% by weight of Si polyol, exhibited an elongation at break after the thermal aging of greater than 50% compared to the elongation at break before thermal aging. The incorporation of an Si polyol thus evidentially results in an improvement in the aging properties.

12. Comparative Example 2—Preparation of a TPU with Aromatic Isocyanate without Si Polyol

(36) A TPU without Si polyol was produced according to the procedure from example 1, the amounts of the components used being shown in table 7. 2 mm and 6 mm test specimens were produced by means of injection molding processes according to the procedure from comparative example 1.

13. Examples 11 and 12—Preparation of Si-Based TPUs with Aromatic Isocyanate and Various Si Polyols, and Also Various Chain Extenders

(37) Si-based TPUs having a content of Si polyol 2 of 10% by weight (example 11) or 20% by weight (example 12) were produced according to the procedure from comparative example 1, the amounts of the components used being shown in table 7. 2 mm and 6 mm test specimens were produced by means of injection molding processes according to the procedure from example 1.

(38) TABLE-US-00008 TABLE 7 Formulations for comparative example 2 and examples 11 and 12 Comparative example 2 Example 11 Example 12 Polyol 1 900.00 g 765.00 g 680.00 g Si polyol 2 0.00 g 85.00 g 170.00 g Chain extender 3 33.26 g 0  0 (diol) Chain extender 4 0.0 g 118.62 g 128.72 g (diamine) Plasticizer 335.5 g 343.68 346.31 g Isocyanate 1 372.15 g 351.48 g 351.48 g Antiblocking 9.73 g 9.97 g 10.04 g agent Antioxidant 1 8.11 g 8.6 g 8.66 g Antioxidant 2 8.11 g 8.6 g 8.66 g

14. Determination of the Thermal Stability of Si-Based TPUs with Aromatic Isocyanate (Accelerated Test)

(39) The test specimens of comparative example 2 and examples 11 and 12 were subjected to accelerated hot air aging tests and tested for their resistance to hot air. To this end, all test specimens were stored in air at 200° C. for 6 hours, the elongation at break was determined prior to this and afterwards. The results are shown in table 8.

(40) TABLE-US-00009 TABLE 8 Elongation at break values for comparative example 2 and examples 11 and 12, in each case before and after thermal aging (accelerated test) Shore hardness Elongation Elongation MFR (Shore A) at break be- at break 190° C./ before ther- fore ther- after ther- 10 kg mal aging mal aging mal aging [g/10 min] Comparative 55A >500% melted 26.6 example 2 Example 11 55A >400% >300% 89.0 Example 12 55A >500% >300% 330

(41) The mechanical performance of a TPU having a low Shore A hardness (55A) and which did not have any Si polyol (comparative example 2) was significantly impaired by the thermal aging even in the accelerated test—the test specimen melted within just a few minutes. In contrast to this, the Si-based TPUs, in this case with Si polyol 2 especially in combination with chain extender 4, even though they had a Shore A hardness of only 55A, displayed only a minor deterioration in the elongation at break in the thermal aging—even after 6 hours this still remained above 300%; in addition the test specimens of examples 11 and 12 both remained dimensionally stable. Since standard TPU materials in the standard case are molten at temperatures above 180° C., this is very good aging performance which is brought about by the incorporation of the Si polyol, especially in combination with the diamine chain extender 4.

15. Example 13 and Comparative Example 3—Preparation of eTPU

(42) 15.1 Preparation of the TPU

(43) The TPUs of example 13 and comparative example 3 were prepared as follows on a reaction extruder. A mixture of the chain extender 3, polyol 1, and also optionally the Si polyol 3 and a catalyst at a charge temperature of 160° C. on the one hand, and, separately from this, the diphenylmethane 4,4′-diisocyanate at a charge temperature of 65° C., and the phenolic antioxidant 3, was metered into the first barrel of a ZSK 58 twin-screw extruder from Coperion—Werner & Pfleiderer, having a processing length of 48 D. The speed of the twin screw was 200 rpm. The set temperature values for the barrels in the downstream direction were between 200 and 230° C. in the first third of the screw, between 210 and 190° C. in the second third of the screw and 190-200° C. in the third and final third of the screw. The output was 200 kg/h. After chopping of the melt by means of underwater pelletization and integrated centrifugal drying, the pellets were subjected to final drying at approx. 80 to 90° C. Table 9 shows the composition of the TPUs, the masses of all constituents being reported in grams.

(44) TABLE-US-00010 TABLE 9 Composition of the TPUs of example 13 and comparative example 3 Comparative Composition Example 13 example 3 Polyol 1 [g] 900.00 1000 Si polyol 3 [g] 100.00 — Isocyanate 1 [g] 633.28 610.6 Chain extender 1 [g] 140.49 133.0 Antioxidant 3 [g] 17.880 18.0 Index 1000 985 MFR (190° C./21.6 kg) after 2 h/ 70 63 110° C. [g/10 min] Shore hardness 85A n.d. n.d.: not determined

(45) TABLE-US-00011 TABLE 10 Composition of the TPUs of examples 14 and 15 Composition Example 14 Example 15 Polyol 1 [g] 900.00 900.00 Si polyol 3 [g] 100.00 100.00 Isocyanate 1 [g] 432.45 685.64 Chain extender 1 [g] 69.35 160.52 Antioxidant 3 [g] 15.16 18.62 Index 1000 1000 Shore hardness 70A 90A

(46) 15.2 Preparation of the eTPU

(47) 99 parts by weight of a dried thermoplastic polyurethane (TPU) and 1 part by weight of a TPU which had been admixed in a separate extrusion process with diphenylmethane 4,4′-diisocyanate having an average functionality of 2.05 were mixed and melted in a twin-screw extruder having a screw diameter of 44 mm and a length-to-diameter ratio of 42. After melting, a mixture of CO.sub.2 (2 parts by weight) and N.sub.2 (0.2 parts by weight) was added as blowing agent. In the course of passage through the rest of the extruder length, the blowing agent and the polymer melt were mixed with one another, so as to form a homogeneous mixture. The total throughput of the extruder, which included a TPU, to which diphenylmethane 4,4′-diisocyanate having an average functionality of 2.05 had been added in a separate extrusion process, and the blowing agent, was 40 kg/h. The melt mixture was subsequently forced using a gear pump (GP) via a diverter valve with screen changer (DV) into a die plate (DP), and cut into pellets in the cutting chamber of the underwater pelletization system (UWP) and transported away with the temperature-controlled and pressurized water and expanded in the process. After separating the expanded pellets from the water by means of a centrifugal dryer, the expanded pellets were dried at 60° C. for 3 h. The temperatures used for the installation parts are listed in table 11 for comparative example 3 and example 13.

(48) TABLE-US-00012 TABLE 11 Temperature data of the installation parts for comparative example 3 and example 13 Temperature Temperature Temperature Temperature range in range of range of range of the extruder the GP the DV the DP (° C.) (° C.) (° C.) (° C.) Comparative 160-220 160-200 160-200 220 example 3 Example 13 180-220 180 180 220

(49) The water temperature and water pressure used for example 13 and comparative example 3 and also the resulting bulk densities of the expanded pellets are listed in table 12.

(50) TABLE-US-00013 TABLE 12 Water temperature and water pressure and the resulting bulk densities of the expanded pellets of example 13 and comparative example 3 Particle Bulk Water pressure Water temperature mass density in the UWP in the UWP (mg) (g/l) (bar) (° C.) Comparative 26 180 15 45 example 3 Example 13 26 190 15 50

(51) 15.2.1 Preparation of the eTPU Based on TPU Having Different Shore Hardnesses

(52) 99 parts by weight of a dried thermoplastic polyurethane (TPU) and 1 part by weight of a TPU which had been admixed in a separate extrusion process with diphenylmethane 4,4′-diisocyanate having an average functionality of 2.05 were mixed and melted in a twin-screw extruder having a screw diameter of 18 mm and a length-to-diameter ratio of 40. After melting, a mixture of CO.sub.2 and N.sub.2 was added as blowing agent. In the course of passage through the rest of the extruder length, the blowing agent and the polymer melt were mixed with one another, so as to form a homogeneous mixture. The total throughput of the extruder, which included a TPU, to which diphenylmethane 4,4′-diisocyanate having an average functionality of 2.05 had been added in a separate extrusion process, and the blowing agent, was 1.75 kg/h. The melt mixture was subsequently forced using a gear pump (GP) via a diverter valve with screen changer (DV) into a die plate (DP), and cut into pellets in the cutting chamber of the underwater pelletization system (UWP) and transported away with the temperature-controlled and pressurized water and expanded in the process. After separating the expanded pellets from the water by means of a centrifugal dryer, the expanded pellets were dried at 60° C. for 3 h. The amounts of blowing agent used and also the temperatures set for the installation parts are listed in table 13.

(53) TABLE-US-00014 TABLE 13 Temperature data of the installation parts for comparative example 3 and example 13 Temperature Temperature Temperature Temperature CO.sub.2 N.sub.2 range in range of range of range of parts by parts by the extruder the GP the DV the DP weight weight (° C.) (° C.) (° C.) (° C.) Example 1.6 0.3 170-215 185 200 200 14 90 A 1.75 0.3 200-220 200 210 230 Example 15

(54) The water temperature and water pressure used for example 14 and example 15 and also the resulting bulk densities of the expanded pellets are listed in table 14.

(55) TABLE-US-00015 TABLE 14 Water temperature and water pressure and the resulting bulk densities of the expanded pellets of example 14 and comparative example 15 Particle Bulk Water pressure Water temperature mass density in the UWP in the UWP (mg) (g/l) (bar) (° C.) Example 14 3.3 136 15 40 90 A Example 3.3 142 15 40 15

16. Dirt Repellency and Easier Cleaning of the eTPUs

(56) Samples of the expanded pellets of example 13 and comparative example 3 were stored with dirt for two weeks in a suspension of 5 g of potting soil and 50 ml of tap water under constant agitation in a screwtop bottle at room temperature. After dirtying, the samples were rinsed under cold running water for 1 minute, without using additional chemical or mechanical cleaning agents. Dirt residue was assessed visually and is listed in table 15.

(57) TABLE-US-00016 TABLE 15 Dirt residue after cleaning the samples after dirt storage (visual assessment). Example 13 Comparative example 3 (with Si polyol) (without Si polyol) Cleanability 0 ++ ++ very dirty/+ dirty/0 no residue and no discolorations of the surface

(58) Comparative example 3 shows distinct soiling of the surface after cleaning. The Si polyol-containing expanded pellets of example 13 were surprisingly very easy to clean and displayed no discolorations of the surface even after storage, that is to say the dirt repellency of the silicone-modified eTPUs was significantly better. This saves an additional coating step in the production of the end products.

17. Examples 16 to 18—Preparation of SI-Based TPUs with Aromatic Isocyanate and Various Hard Segment Contents/Various Contents of SI Polyol

(59) Further Si-based TPUs with aromatic isocyanate were prepared analogously to the procedure of example 1, with the individual components being used in the amounts reported in table 16 (formulations); Si polyol 3 and polyol 1 were in this case always consistently used in the Si polyol 3:polyol 1 weight ratio of 4:1.

(60) TABLE-US-00017 TABLE 16 Formulations for examples 16 to 18 Example 16 Example 17 Example 18 [g] [g] [g] Polyol 1 200 160 130 Si polyol 3 800 640 520 Chain 102.55 164.08 199.98 extender 1 Isocyanate 1 446.77 585.24 660.61 Antioxidant 1 7.82 7.82 7.63 Antioxidant 2 7.82 7.82 7.63

(61) For the test specimens of examples 16 to 18, the tear propagation resistance, the elongation at break and the Shore hardnesses A and D were measured and the hard segment content was determined. Table 17 below shows the results of the tests.

(62) TABLE-US-00018 TABLE 17 Results of the mechanical investigations for the Si-based TPUs having various hard segment contents of examples 16 to 18 Hard segment Tear content Tensile Elongation propagation [% by Shore Shore strength at break resistance weight] A D [MPa] [%] [kN/m] Example 25 74 15 / / 6 16 Example 40 94 36  7  20 13 17 Example 50 98 57 19 240 87 18

(63) It was surprisingly found that for an Si-based TPU having a high polysiloxane diol content, of 80% by weight based on the polyol content in examples 16-18, the mechanical properties, in particular the tensile strength, elongation at break and the tear propagation resistance, deteriorate significantly. The examples given above show that this can be observed for a wide range of the hard segment content.