AGING-RESISTANT TPU

Abstract

The present invention relates to thermoplastic polyurethanes obtainable or obtained by a process comprising the reaction of a thermoplastic polyester (PE-1) with a diol (D1) to give a composition (Z1) comprising a polyester (PE-2), and the reaction of the composition (Z1) obtained in step (i) with an isocyanate composition (I1) comprising at least one polyisocyanate, and with a polyol composition (P1), where the polyol composition (P1) comprises at least one polycarbonate polyol (PC1), and also to a process for the production of the thermoplastic polyurethane. The present invention further relates to a composition comprising a thermoplastic polyurethane of the invention and at least one flame retardant. The present invention also relates to the use of this thermoplastic polyurethane for the production of cable sheathing, and also to films, moldings, rollers, fibers, automobile cladding, hoses, cable plugs, folding bellows, drag cables, cable sheathing, gaskets, belts or damping elements comprising this thermoplastic polyurethane.

Claims

1-15. (canceled)

16. A thermoplastic polyurethane obtained by a process comprising: (i) reacting a thermoplastic polyester (PE-1) with a diol (D1) to give a composition (Z1) comprising a polyester (PE-2), and (ii) reacting the composition (Z1) with an isocyanate composition (I1) comprising a polyisocyanate, and with a polyol composition (P1), wherein the polyol composition (P1) comprises a polycarbonate polyol (PC1), wherein a molar mass of the thermoplastic polyester (PE-1) is in a range from 15 000 g/mol to 70 000 g/mol and a molar mass of the polyester (PE-2) is in a range from 1000 g/mol to 6000 g/mol, and wherein the diol (D1) is 1,4-butanediol.

17. The thermoplastic polyurethane according to claim 16, wherein the polycarbonate polyol (PC1) is at least one selected from the group consisting of a polycarbonatediol based on butanediol and hexanediol, a polycarbonatediol based on pentanediol and hexanediol, and a polycarbonatediol based on hexanediol.

18. The thermoplastic polyurethane according to claim 16, wherein a number-average molecular weight Mn of the polycarbonate polyol (PC1) is in a range from 500 to 4000, determined by GPC.

19. The thermoplastic polyurethane according to claim 16, wherein the thermoplastic polyester (PE-1) is selected from the group consisting of a polyalkylene terephthalate and poly-L-lactic acid.

20. The thermoplastic polyurethane according to claim 16, wherein the polyisocyanate is selected from the group consisting of hexamethylene diisocyanate and diphenylmethane diisocyanate (MDI).

21. The thermoplastic polyurethane according to claim 16, wherein a Shore hardness of the thermoplastic polyurethane is in a range from Shore A to 78 Shore D.

22. A process for producing a thermoplastic polyurethane, the process comprising: (i) reacting a thermoplastic polyester (PE-1) with a diol (D1) to give a composition (Z1) comprising a polyester (PE-2), and (ii) reacting the composition (Z1) with an isocyanate composition (I1) comprising a polyisocyanate, and with a polyol composition (P1), wherein the polyol composition (P1) comprises a polycarbonate polyol (PC1), wherein a molar mass of the thermoplastic polyester (PE-1) is in a range from 15 000 g/mol to 70 000 g/mol and a molar mass of the polyester (PE-2) is in a range from 1000 g/mol to 6000 g/mol, and wherein the diol (D1) is 1,4-butanediol.

23. A composition comprising components (A) and (B): (A) the thermoplastic polyurethane according to claim 16, (B) a flame retardant.

24. The composition according to claim 23, wherein the flame retardant is selected from the group consisting of a metal hydroxide, a nitrogen-containing flame retardant and a phosphorus-containing flame retardant.

25. The composition according to claim 23, wherein a total content of the thermoplastic polyurethanes in the composition is from 20% by weight to 80% by weight, based on an entire composition.

26. A cable sheathing, comprising the thermoplastic polyurethane according to claim 16.

27. A film, molding, roller, fiber, automobile cladding, hose, cable plug, folding bellows, drag cable, cable sheathing, gasket, belt or damping element comprising the thermoplastic polyurethane according to claim 16.

Description

EXAMPLES

1. Raw Materials:

[0122] Poly PTHF1000: Polytetrahydrofuran 1000, CAS number: 25190-06-1, BASF SE, 67056 Ludwigshafen, GERMANY, Intermediates Division. [0123] 1,4-Butanediol: Butane-1,4-diol, CAS number: 110-63-4, BASF SE, 67056 Ludwigshafen, GERMANY, Intermediates Division. [0124] Lupranat MET: 4,4-Methylenediphenyl diisocyanate, CAS number: 101-68-8, BASF SE, 67056 Ludwigshafen, GERMANY. [0125] Polyol A: Copolyesterdiol based on 1,4-butanediol, 1,6-hexanediol (ratio 2:1) and adipic acid, water content % (w/w)<0.1, acid number [KOH mg/g]<0.6, OH number [KOH mg/g]=48-53. [0126] Capromer PD1-20 (PolyCLO NPG2000): Polycaprolactone, CAS number: 69089-45-8, water content % (w/w)<0.1, acid number [KOH mg/g]<0.25, OH number [KOH mg/g]=54-58. [0127] Eternacoll PH-200D: Polycarbonatediol based on 1,6-hexanediol and 1,5-pentanediol in the ratio 1:1, water content % (w/w)<0.1, acid number [KOH mg/g]<0.1, OH number [KOH mg/g]=51-61; UBE Chemical Europe S.A., 28016 Madrid, Spain. [0128] Irganox 1010: Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), CAS Number: 6683-19-8, BASF SE, 67056 Ludwigshafen, GERMANY. [0129] Irganox 1098: N,N-Hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide], CAS number: 23128-74-7, BASF SE, 67056 Ludwigshafen, GERMANY. [0130] Elastostab H01: Hydrolysis stabilizer for polyester polyurethane, BASF Polyurethanes GmbH, 49440 Lemfoerde, GERMANY. [0131] Tin dioctanoate: Catalyst metal 93690, tin bis(2-ethylhexanoate), CAS number: 301-10-0, BASF Polyurethanes GmbH, 49440 Lemfoerde, GERMANY. [0132] Melapur MC 15 ED: Melamine cyanurate (1,3,5-triazine-2,4,6(1H,3H,5H)trione, with 1,3,5-triazine-2,4,6-triamine (1:1)), CAS #: 37640-57-6, BASF SE, 67056 Ludwigshafen, GERMANY, particle size D99%</=50 m, D50%<=4.5 m, water content % (w/w)<0.2. [0133] Ultradur B4500 NAT: Polymer based on: polybutylene terephthalate (PBT), BASF SE, 67056 Ludwigshafen, GERMANY.

2. Production by the Manual Casting Process

[0134] The quantity specified in the parent formulation of polyol and of the chain extenders is weighed in a tin-plated steel container and briefly blanketed with nitrogen. The container is closed with a lid and heated to about 90 C. in an oven.

[0135] Another oven is preheated to 80 C. for the heat-conditioning of the skin. The Teflon dish is placed on the hotplate, which is set to 125 C.

[0136] The calculated quantity of liquid isocyanate is determined volumetrically. For this, the liquid isocyanate is weighed in a PE beaker and poured out within 10 s into a PE beaker (the volumetric determination being carried out for MDI at a temperature of about 48 C.). The resultant emptied beaker is then tared, and the calculated quantity of isocyanate is charged thereto. In the case of MDI, this is stored at about 48 C. in an oven.

[0137] Additions such as hydrolysis stabilizer, antioxidant, etc., where these are solid at RT, are weighed in directly.

[0138] The preheated polyol is placed on an elevating platform under the stirrer, which is at rest. The reaction vessel is then raised by the elevating platform until the stirrer blades are completely immersed in the polyol.

[0139] Before the stirrer motor is switched on, it is vital to ensure that the rotation rate controller is set at zero. The rotation rate is then slowly controlled upward in a manner that ensures good mixing without incorporation of air.

[0140] Additives, e.g. antioxidants, are then added to the polyol.

[0141] The temperature of the reaction mixture is carefully set to 80 C. by using a hot-air blower.

[0142] If necessary, prior to addition of isocyanate, catalyst is metered into the reaction mixture by using a microliter syringe. Isocyanate is then added at 80 C. by introducing the quantity previously determined volumetrically within a period of 10 s into the reaction mixture. The weight is monitored by reweighing. Deviations of 0.2 g from the quantity in the formulation are recorded. The stopwatch is started when the isocyanate is added. When the temperature reaches 110 C., the reaction mixture is poured out into the Teflon dishes, which have been preheated to 125 C.

[0143] 10 min after the stopwatch was started, the skin is removed from the hotplate and then stored at 80 C. for 15 h in an oven. The cooled skin is comminuted in the chopper mill. The granulate is then dried at 110 C. for 3 h and stored under dry conditions.

[0144] This method can also in principle be used in a reactive extruder or in the belt process.

3. Reactive Extruder ProcessProduction as Described in EP 1419188 B1

[0145] The TPU described below were produced in a ZSK 58 twin-screw extruder from Werner & Pfleiderer. The length of the processing section of the extruder was 12 barrel sections, and the length of the actual barrel sections was 4 times the screw diameter. A gear pump was used to discharge material from the extruder; conventional underwater pelletization equipment was used for granulation. The resultant granulate was then dried in a fluidized-bed dryer at from 60 to 100 C. with residence times of from 5 to 10 min. to water content <0.03%, and then heat-conditioned for 15 hours at 80 C.

[0146] The temperatures of the extruder barrel sections were as follows: 1-260 C., 2-4from 290 to 250 C., 5-240 C., 6-12, inclusive of melt-discharge equipment230 C. Under these conditions, the resultant melt temperature with throughput about 200 kg/h and rotation rate 200 rpm was from 220-230 C.

[0147] A commercially available polybutylene terephthalate (Ultradur B 4500/BASF Aktiengesellschaft) was used as semicrystalline, high-molecular-weight polyester, 1,4-butanediol was used as low-molecular-weight diol for the degradation of the high-molecular-weight PBT, and 4,4-diisocyanatodiphenylmethane (MDI) was used as aromatic diisocyanate. The polydiols (PDO) used are described and characterized in Table 1.

[0148] Ultradur granulate was metered continuously into barrel section 1 of the twin-screw extruder, and 1,4-butanediol was metered into barrel section 3 together with tin dioctanoate as catalyst to accelerate degradation. Polyol, MDI and tin dioctanoate were added in barrel section 5 of the twin-screw extruder. Stabilizers (Elastostab H01 and Irganox 1125) were metered into barrel section 8 of the twin-screw extruder via metering equipment attached at the side.

4. Compounding

[0149] The respective mixtures were produced by ZE 40 A twin-screw extruder from Berstorff, the length of the processing section being 35 D, divided into 10 barrel sections. The flame retardant was metered into zone 5 here. Conventional underwater pelletization equipment was used for granulation. The resultant granulate was then dried in a fluidized-bed dryer at from 60 to 100 C. with residence times of from 5 to 10 min. to water content <0.03%, and then heat-conditioned for 15 hours at 80 C.

5. Formulations of TPU 1-7

[0150]

TABLE-US-00001 TABLE 1 TPU 1 TPU 2 TPU 3 TPU 4 TPU 5 TPU 6 TPU 7 Production Manual Manual Manual Extruder Extruder Extruder Extruder process casting casting casting process process process process PTHF 1000 1000 1000 Polyol A 1000 1000 Capromer 1000 PD1-20 Eternacoll 1000 1000 PH-200D Ultradur 785.312 434.9 483.54 714.354 B4500 NAT Lupranat MET 630 440 565 400.125 195.08 203.71 224.096 1,4-Butanediol 136.74 111.62 156.64 48.954 20.66 22.89 32.146

[0151] 0.5% of Irganox 1010, 0.5% of Irganox 1098, 1% of Elastostab H01, and also 200 ppm of tin dioctanoate as catalyst were respectively added to all of the formulations.

6. Formulations of flame-retardant TPUCompounded material 1-4

TABLE-US-00002 TABLE 2 Compounded Compounded Compounded Compounded material 1 material 2 material 3 material 4 (comparative (comparative (comparative (of the example) example) example) invention) Production process Compounding Compounding Compounding Compounding TPU 1 80 TPU 3 80 TPU 4 80 TPU 7 80 Melapur MC 15 ED 20 20 20 20 MFR 190 C. 2.16 kg 17 32 21 61 [g/10 min] DIN EN ISO 1133

7. Production of Test Specimens

[0152] An Arenz single-screw extruder with three-zone screw with mixing section (screw ratio 1:3) was used to extrude films of thickness 1.6 mm from the granulates.

8. Determination of Mechanical Properties

[0153] The following were measured on the corresponding test samples: tensile strength or elongation at break (in accordance with DIN 53504), density (DIN EN ISO 1183-1, A), tear strength (DIN ISO 34-1, (b)), abrasion (DIN 53516) and Shore A hardness (in accordance with DIN 53505).

TABLE-US-00003 TABLE 3 TPU 1 TPU 2 TPU 3 TPU 4 TPU 5 TPU 6 TPU 7 Density [g/cm.sup.3] 1.12 1.19 1.21 1.16 1.19 1.18 1.23 Shore A 87 87 91 91 85 85 92 Tensile strength 45 50 43 41 45 46 47 [MPa] Elongation at 600 650 490 730 750 690 500 break [%] Tear strength 70 70 114 87 65 69 117 [kN/m] Abrasion [mm.sup.3] 25 30 38 36 35 43 38

TABLE-US-00004 TABLE 4 Compounded Compounded Compounded Compounded Standard material 1 material 2 material 3 material 4 mechanical (comparative (comparative (comparative (of the properties example) example) example) invention) Density [g/cm.sup.3] [g/cm.sup.3] 1.193 1.263 1.229 1.293 Shore A [A] 91 87 96 96 Tensile [MPa] 42 35 18 26 strength [MPa] Elongation [%] 540 550 600 510 at break [%] Tear [kN/m] 65 78 73 102 strength [kN/m] Abrasion [mm.sup.3] [mm.sup.3] 31 44 55 34

9. Determination of Aging Resistance and Hydrolysis Resistance

[0154] The expression oxidative aging is used in the context of this invention when the mechanical parameters of the thermoplastic polyurethanes, for example tensile strength, elongation at break, tear strength, flexibility, impact resistance, softness, etc., undergo adverse changes over the course of time.

[0155] Resistance to oxidative aging is evaluated by suspending a test sample in a convection oven at 150 C. for 3000 h, at 175 C. for 240 hand at 200 C. for 6h, and then determining mechanical parameters. The tables below collate the results.

[0156] Hydrolysis resistance is evaluated by storing a test sample at 85 C. and 85% relative humidity for 3000 hours, and then determining mechanical parameters. The tables below collate the results.

TABLE-US-00005 TABLE 5 TPU 1 TPU 2 TPU 3 TPU 4 TPU 5 TPU 6 TPU 7 Hot-air aging 200 C./6 h Tensile strength [MPa] ** ** ** 20 ** ** 26 (Difference from 0 h [%]) (51) (45) Elongation at break [%] ** ** ** 590 ** ** 670 (Difference from 0 h [%]) (19) (+34) Hot-air aging 175 C./240 h Tensile strength [MPa] [MPa] ** ** ** ** 18 23 27 (Difference from 0 h [%]) (60) (50) (43) Elongation at break [%] [%] ** ** ** ** 340 460 300 (Difference from 0 h [%]) (54) (33) (40) Hot-air aging 150 C./3000 h Tensile strength [MPa] [MPa] ** 9 41 ** 17 21 20 (Difference from 0 h [%]) (82) (5) (62) (54) (58) Elongation at break [%] [%] ** 420 190 ** 310 250 310 (Difference from 0 h [%]) (35) (61) (58) (74) (38) Humid heat 85/85/3000 h Tensile strength [MPa] [MPa] 31 ** 36 21 ** ** 25 (Difference from 0 h [%]) (31) (16) (49) (47) Elongation at break [%] [%] 470 ** 470 770 ** ** 250 (Difference from 0 h [%]) (22) (4) (+5) (50) ** sample destroyed

[0157] The TPU 7 of the invention meets the requirements of temperature class D, and also the more stringent specifications of LV112 for hydrolysis resistance.

TABLE-US-00006 TABLE 6 Compounded Compounded Compounded Compounded material 1 material 2 material 3 material 4 (comparative (comparative (comparative (of the example) example) example) invention) Hot-air aging 200 C./6 h Tensile strength [MPa] [MPa] ** ** 8(56) 14(46) (Difference from 0 h [%]) Elongation at break [%] [%] ** ** 130(78) 490(4) (Difference from 0 h [%]) Hot-air aging 175 C./240 h Tensile strength [MPa] [MPa] ** ** 11(39) 18(31) (Difference from 0 h [%]) Elongation at break [%] [%] ** ** 2(100) 280(45) (Difference from 0 h [%]) Hot-air aging 165 C./1000 h Tensile strength [MPa] [MPa] ** ** ** 14(46) (Difference from 0 h [%]) Elongation at break [%] [%] ** ** ** 100(80) (Difference from 0 h [%]) Hot-air aging 150 C./3000 h Tensile strength [MPa] [MPa] ** ** ** 17(35) (Difference from 0 h [%]) Elongation at break [%] [%] ** ** ** 160(69) (Difference from 0 h [%]) Humid heat 85/85/3000 h Tensile strength [MPa] [MPa] 14(67) 15(57) 8(56) 10(62) (Difference from 0 h [%]) Elongation at break [%] [%] 630(+17) 580(+5) 120(80) 380(25) (Difference from 0 h [%]) ** sample destroyed

[0158] Compounded material 4 of the invention meets the requirements of temperature class D, and also the more stringent specifications of LV112 for hydrolysis resistance.

REFERENCES

[0159] Kunststoffhandbuch, Band 7, Polyurethane [Plastics handbook, vol. 7, Polyurethanes], Carl Hanser Verlag, 3.sup.rd edn., 1993, chapter 3.1 [0160] Kunststoffhandbuch, Band VII [Plastics handbook, vol. VII], eds. Vieweg and Hchtlen, Carl Hanser Verlag, Munich, 1966 (pp. 103-113)