TRANSPARENT HARD THERMOPLASTIC POLYURETHANES

Abstract

The present invention relates to a thermoplastic polyurethane obtainable or obtained by reacting a polyisocyanate composition, a chain extender, and a polyol composition, wherein the polyol composition comprises at least one polyol (P1) which has a molecular weight Mw in the range from 500 to 2500 g/mol and has at least one aromatic polyester block (B1), wherein the polyol (P1) includes 20% to 70% by weight of the aromatic polyester blocks (B1), based on the overall polyester polyol (P1). The present invention further relates to a process for producing a shaped body comprising such a thermoplastic polyurethane, and to shaped bodies obtainable or obtained by a process of the invention.

Claims

1-16. (canceled)

17. A thermoplastic polyurethane, obtainable or obtained by reacting at least the following components (I) to (iii): (i) a polyisocyanate composition, (ii) a chain extender, and (iii) a polyol composition, wherein the polyol composition comprises a polyol (P1) having a molecular weight Mw in a range of from 500 to 2500 g/mol and having an aromatic polyester block (B1), wherein the polyol (P1) comprises 20% to 70% by weight of the aromatic polyester block (B1), based on the overall polyester polyol (P1), and wherein the molecular weight Mw is calculated according to the formula:
Mw=1000 mg/g.Math.[(z.Math.56.106 g/mol)/(OHN [mg/g])], where z=2, and wherein a hard segment content in the thermoplastic polyurethane is greater than 65%.

18. The thermoplastic polyurethane of claim 17, wherein the chain extender of (ii) and the polyol (P1) present in the polyol composition are employed in a molar ratio of 100:1 to 1:1.

19. The thermoplastic polyurethane of claim 17, wherein the polyol (P1) comprises 25% to 65% by weight of the aromatic polyester block (B1), based on the overall polyester polyol (P1).

20. The thermoplastic polyurethane of claim 17, wherein the aromatic polyester block (B1) is a polyester of an aromatic dicarboxylic acid and an aliphatic diol.

21. The thermoplastic polyurethane of claim 17, wherein the aromatic polyester block (B1) is a polyethylene terephthalate block or a polybutylene terephthalate block.

22. The thermoplastic polyurethane of claim 17, wherein the polyol (P1) has a molecular weight Mw in a range of from 500 to 2300 g/mol.

23. The thermoplastic polyurethane of claim 17, wherein the chain extender of (ii) is a diol having a molecular weight Mw<220 g/mol.

24. The thermoplastic polyurethane of claim 17, wherein the chain extender of (ii) and the polyol (P1) present in the polyol composition are employed in a molar ratio of 80:1 to 5:1.

25. The thermoplastic polyurethane of claim 17, wherein the polyol composition comprises a further polyol selected from the group consisting of a polyetherol, a polyesterol, a polycarbonate alcohol and a hybrid polyol.

26. The thermoplastic polyurethane of claim 17, wherein the polyisocyanate is an aromatic diisocyanate.

27. The thermoplastic polyurethane of claim 17, wherein the hard segment content in the thermoplastic polyurethane is in a range of from 75% to 99%.

28. A process for producing a shaped body (SC), the process comprising: (a) preparing a thermoplastic polyurethane, wherein the preparing comprises reacting at least the following components (i) to (iii): (i) a polyisocyanate composition, (ii) a chain extender, and (iii) a polyol composition, wherein the polyol composition comprises a polyol (P1) having a molecular weight Mw in a range of from 500 to 2500 g/mol and having an aromatic polyester block (B1), wherein the polyol (P1) comprises 20% to 70% by weight of the aromatic polyester block (B1), based on the overall polyester polyol (P1), and wherein the molecular weight (Mw) is calculated according to the formula:
Mw=1000 mg/g.Math.[(z.Math.56.106 g/mol)/(OHN [mg/g])], where z=2, and wherein a hard segment content in the thermoplastic polyurethane is greater than 65%; and (b) producing a shaped body (SC) from the thermoplastic polyurethane.

29. The process of claim 28, wherein the shaped body (SC) is produced in (b) by extrusion, injection molding or sintering methods or from solution.

30. A shaped body, obtainable or obtained by the process of claim 28.

31. The shaped body of claim 30, wherein the shaped body is a film.

Description

EXAMPLES

1 the Following Feedstocks were Used

[0215] Polyol 1: polyester polyol based on adipic acid, PET, butane-1,4-diol and diethylene glycol with an OH number of 111.2, functionality: 2 [0216] Polyol 2: polyester polyol based on adipic acid, PET, butane-1,4-diol and propane-1,3-diol with an OH number of 112.1, functionality: 2 [0217] Polyol 3: polyester polyol based on adipic acid, PET and diethylene glycol with an OH number of 50, functionality: 2 [0218] Isocyanate 1: aromatic isocyanate (methylene diphenyl 4,4′-diisocyanate) [0219] CE 1: butane-1,4-diol [0220] CE 2: hexane-1,6-diol [0221] Stabilizer 1: hydrolysis stabilizer based on polycarbodiimide

2 Synthesis of the Polyester Polyols with PET Blocks

[0222] 2.1 Synthesis of Polyol 1 [0223] A 4000 ml round-neck flask provided with PT100 thermocouple, nitrogen inlet, stirrer, column, column head, Anschutz-Thiele attachment and heating mantle is initially charged with 880.84 g of adipic acid, 395.56 g of butane-1,4-diol (3% excess) and 465.79 g of diethylene glycol (3% excess). The mixture is then heated to 120° C. until a homogeneous mixture is formed. 1000 g of polyethylene terephthalate (PET) are then added to the mixture, and then 10 ppm=2.5 g of TTB (tetra-n-butyl orthotitanate, 1% in toluene). The reaction mixture is heated first to 180° C. for about 1.5 h and then further to 240° C., and the resultant water of reaction is continuously removed. Over the entire synthesis, the PET flakes are gradually degraded, and a transparent mixture is formed, which is condensed until a product having an acid number<1.0 mg KOH/g is obtained. [0224] The polymer obtained has the following properties: [0225] Hydroxyl number: 111.2 mg KOH/g [0226] Acid number: 0.45 mg KOH/g [0227] Viscosity at 75° C.: 757 mPas

[0228] 2.2 Synthesis of Polyol 2 [0229] A 4000 ml round-neck flask provided with PT100 thermocouple, nitrogen inlet, stirrer, column, column head, Anschutz-Thiele attachment and heating mantle is initially charged with 788.52 g of adipic acid, 309.27 g of propane-1,3-diol (3% excess) and 366.24 g of butane-1,4-diol (3% excess). The mixture is then heated to 120° C. until a homogeneous mixture is formed. 1250 g of polyethylene terephthalate (PET) are then added to the mixture, and then 10 ppm=2.5 g of TTB (tetra-n-butyl orthotitanate, 1% in toluene). The reaction mixture is heated first to 180° C. for about 1.5 h and then further to 240° C., and the resultant water of reaction is continuously removed. Over the entire synthesis, the PET flakes are gradually degraded, and a transparent mixture is formed, which is condensed until a product having an acid number<1.0 mg KOH/g is obtained. [0230] The polymer obtained has the following properties: [0231] Hydroxyl number: 112.1 mg KOH/g [0232] Acid number: 0.38 mg KOH/g [0233] Viscosity at 75° C.: 1803 mPas

[0234] 2.3 Synthesis of Polyol 3 [0235] A 4000 ml round-neck flask provided with PT100 thermocouple, nitrogen inlet, stirrer, column, column head, Anschutz-Thiele attachment and heating mantle is initially charged with 1099.59 g of adipic acid and 921.43 g of diethylene glycol (no excess). The mixture is then heated to 120° C. until a homogeneous mixture is formed. 750 g of polyethylene terephthalate (PET) are then added to the mixture in the form of flakes, and then 10 ppm=2.5 g of TTB (tetra-n-butyl orthotitanate, 1% in toluene). The reaction mixture is heated first to 180° C. for about 1.5 h and then further to 240° C., and the resultant water of reaction is continuously removed. Over the entire synthesis, the PET flakes are gradually degraded, and a transparent mixture is formed, which is condensed until a product having an acid number<1.0 mg KOH/g is obtained. [0236] The polymer obtained has the following properties: [0237] Hydroxyl number: 50 mg KOH/g [0238] Acid number: 0.38 mg KOH/g [0239] Viscosity at 75° C.: 1936 mPas

3 Methods

[0240] 3.1 Determination of Viscosity: [0241] Unless stated otherwise, the viscosity of the polyols was determined at 75° C. to DIN EN ISO 3219 (01.10.1994 edition) with a Rheotec RC 20 rotary viscometer using the CC 25 DIN spindle (spindle diameter: 12.5 mm; internal measuring cylinder diameter: 13.56 mm) at a shear rate of 50 1/s.

[0242] 3.2 Measurement of Hydroxyl Number: [0243] Hydroxyl numbers were determined by the phthalic anhydride method DIN 53240 (01.12.1971 edition) and reported in mg KOH/g.

[0244] 3.3 Measurement of Acid Number: [0245] Acid number was determined to DIN EN 1241 (01.05.1998 edition) and is reported in mg KOH/g.

4 General Preparation Example

[0246] The polyols were initially charged in a container at 80° C. and mixed by vigorous stirring with the components according to table 1. The reaction mixture was heated to above 110° C. and was then poured out onto a heated, Teflon-coated table. The cast slab obtained was heat-treated at 80° C. for 15 hours, then pelletized and processed by injection molding.

TABLE-US-00001 TABLE 1 Example compounds used Example A Example 1 Example 2 Polyol 1 [g] 650 Polyol 2 [g] 240 Polyol 3 [g] 130 CE 1 [g] 143.2 319 CE 2 [g] 419.2 Isocyanate 1 [g] 562 903 947.9 Stabilizer 1 [g] 6.5 1.9 Index 1000 1000 1000 Hard segment 40% 90% 80% content Starting  80° C.  70° C.  80° C. temperature Casting 110° C. 110° C. 110° C. temperature

5 Mechanical Properties

[0247] The measurements collated in table 2 were established from injection-molded sheets of the examples. [0248] The following properties of the obtained polyurethanes were determined by the recited methods: [0249] Shore hardness: DIN ISO 7619-1 [0250] Tensile strength and elongation at break: DIN 53504 [0251] Modulus of elasticity: DIN EN ISO 527

TABLE-US-00002 TABLE 2 Mechanical properties of examples 1 and 2 and of example A Modulus of Modulus of Shore Elongation at elasticity at elasticity at hardness break [%] RT [MPa] 70° C. [MPa] Comparative 80 D 320 2038 27 example 1 Example 1 83 D 240 2742 1299 Example 2 80 D 200 2237 1652

CITED LITERATURE

[0252] U.S. Pat. No. 5,574,092 [0253] U.S. Pat. No. 5,627,254 [0254] WO 2015/063062 A1 [0255] WO 2007/118827 A1 [0256] Kunststoffhandbuch, volume 7, “Polyurethane”, Carl Hanser Verlag, 3rd edition, 1993, chapter 3.1 [0257] Kunststoffhandbuch, volume 7, Carl Hanser Verlag, 1st edition 1966, p. 103-113