Melt spun multifilaments based on thermoplastic polyurethane, their production and use

Abstract

The invention relates to melt spun multifilaments based on thermoplastic polyurethane, their production and the use of said melt spun multifilaments to produce technical textiles and clothing such as socks, stockings, compression textiles like medical bandage, surgical hose, orthopedic elastic bandage, sport textiles, underwear etc.

Claims

1. Melt spun multifilaments based on thermoplastic polyurethane obtained by the reaction of A) at least one organic diisocyanate B) at least one polyol with a number-average molar mass M.sub.n≥500 and ≤5000 g/mol, and at least two isocyanate-reactive groups C) at least one chain extender with a molar mass ≥60 and ≤490 g/mol, and with two isocyanate-reactive groups and D) optionally a monofunctional chain terminator which has an isocyanate-reactive group E) optionally catalysts F) optionally auxiliaries and/or additives, where component B) comprises B1) at least one polyether carbonate polyol obtainable via an addition reaction of carbon dioxide and alkylene oxides onto H-functional starter substances B2) 0 to 70% by weight based on B) of at least one or more polyols which are different from B1) and where the molar ratio of the isocyanate groups from A) to the entirety of the isocyanate-reactive groups in B), C) and optionally D) is ≥0.9:1 and ≤1.2:1.

2. The melt spun multifilaments according to claim 1 based on thermoplastic polyurethane which is obtained by the reaction of A) at least one organic diisocyanate selected from the group consisting of 4,4′-methylene-diphenyldiisocyanate (4,4′-MDI), 1,6-hexamethylenediisocyanate and 4,4′-diisocyanato-dicyclohexylmethane (hydrogenated 4,4′-MDI) B) at least one polyol with a number-average molar mass M.sub.n≥1000 and ≤3000 g/mol, and with a number-average functionality of 1.9 to 2.1 C) at least one chain extender with a molar mass ≥60 and ≤300 g/mol, and with two isocyanate-reactive groups and D) optionally a monofunctional chain terminator which has an isocyanate-reactive group E) optionally catalysts F) optionally auxiliaries and/or additives, where component B) comprises B1) at least one polyether carbonate polyol obtainable via an addition reaction of carbon dioxide and propylene oxide or a mixture of propylene oxide with up to 30% by weight, based on the alkylene oxide mixture, of ethylene oxide onto H-functional starter substances B2) 0 to 70% by weight based on B) of at least one or more polyols which are different from B1) and where the molar ratio of the isocyanate groups from A) to the entirety of the isocyanate-reactive groups in B), C) and optionally D) is ≥0.9:1 and ≤1.2:1.

Description

EXAMPLES

Production of the TPU Granules

(1) The TPUs were continuously produced as follows:

(2) The mixture comprising the polyol/polyol mixture (B), Tyzor AA105 (E) and additives (F), which had been heated to about 200° C., was intensively mixed together with the isocyanate (A), which had been heated to about 170° C. by means of a heat exchanger, in a pipe with 4 static mixers manufactured by Sulzer (Type DN6 with 10 mixer elements and a shearing rate of 500 sec.sup.−1). The mixture was then fed into the inlet of a screw device (ZSK 53 manufactured by Werner & Pfleiderer) and was then fed through the extruder with a number of revolutions of 280 r.p.m. at 200° C. At the end of the extruder the TPU strands were cooled by water, cut into granules and then dried.

(3) Table 1 describes the components used and the proportions thereof, for the production of the TPUs.

(4) TABLE-US-00001 TABLE 1 Molar proportions of the starting components for the synthesis of the TPUs 1,4-Butanediol/ Polyol 4,4′-MDI 1,6-Hexanediol Catalyst Additives Example Polyol no. [mol] [mol] [mol] [ppm] [% by weight] 1 1 and 2 0.5 and 4.01 2.76 and 0.25 C1: 34.5 A1: 0.06 0.5 A9: 0.90 2 1 and 2 0.5 and 4.54 3.46 and 0.0 C1: 15 A1: 0.10 0.5 A3: 0.30 A4: 0.35 A7: 0.12 A9: 0.50 3* 1 1 3.18 1.98 and 0.20 C1: 30 A1: 0.33 A3: 0.91 A8: 0.11 A9: 0.59 4* 6 1 2.27 1.27 C2: 250 A1: 0.24 A5: 0.50 A6: 0.30 A10: 0.59 5* 3 and 4 0.5 and 4.49 3.49 C1: 8 A1: 0.10 and 5 0.17 and A2: 0.30 0.33 A9: 0.27 *comparative example

(5) Polyol 1: Acclaim® 2200N: Polypropylene oxide glycol with OH number 56.1 mg KOH/g (M.sub.n=2000 g/mol) from Covestro AG.

(6) Polyol 2: Polyether carbonate diol based on propylene oxide and CO.sub.2 with OH number 54.3 mg KOH/g (M.sub.n=2066 g/mol) and with 18.7% by weight incorporated CO.sub.2 content.

(7) Polyol 3: Desmophen® C2201: Polycarbonate diol with OH number of 56.2 mg KOH/g (Mn=1996 g/mol) from Covestro AG

(8) Polyol 4: Polybutylene adipate with OH number of 50.1 mg KOH/g (Mn=2240 g/mol)

(9) Polyol 5: Polybutylen/ethylene adipate with OH number of 55.1 mg KOH/g (Mn=2036 g/mol

(10) Polyol 6: TERATHANE® PTMEG 2000: Polytetramethylene glycol with OH number of 55.8 mg/KOH/g (Mn=2011 g/mol) from INVISTA

(11) MDI: Desmodur® 44M with NCO content of 33.6% from Covestro AG

(12) Catalyst 1: Tyzor® AA105: Titanium catalyst from Dorf Ketal

(13) Catalyst 2: Tin dioctoate

(14) Additive 1: Irganox® 1010: Antioxidant from BASF SE

(15) Additive 2: Stabaxol® I: hydrolytic stabilizer from Rhein Chemie GmbH

(16) Additive 3: Oil M350: Silicon oil from Momentive

(17) Additive 4: Tinuvin® PUR 866: Light stabilizer from BASF SE

(18) Additive 5: Tinuvin® 234: Light stabilizer from BASF SE

(19) Additive 6: Tinuvin® 622: Light stabilizer from BASF SE

(20) Additive 7: Irgafos® 126: Antioxidant from BASF SE

(21) Additive 8: Irgafos® P-EPQ: Antioxidant from BASF SE

(22) Additive 9: Loxiol® 3324: N,N′-ethylene-bis-stearamide from Emery Oleochemicals

(23) Additive 10: Licowax® E: Ester of montanic acids with multifunctional alcohols from Clariant

DESCRIPTION OF THE MELT SPINNING MACHINE AND ITS PREPARATION

(24) Before melt spinning, it should be ensured that the TPU does not contain more than 0.02% by weight of moisture. In order to achieve this low water content, the TPU granules were dried overnight under vacuum at 80° C. in an oven. The dried TPU granules were collected in aluminum bags and sealed with a hot press to protect the dried granules from atmospheric moisture.

(25) The melt spinning machine used consists of the following parts: a hopper 1, an extruder 2, a spinning pump 3, a spinning head 4, a filament quenching unit 5, a take-up roller 6, duo rollers 7, optionally a relaxation unit 8 and a winder 9 [see FIG. 1]. The melt spinning machine was prepared before the melt spinning experiment as follows: The extruder 2, spinning pump 3 and spinning head 4 were heated.

(26) Then the dried polymer was filled into the hopper 1 under a constant flow of nitrogen to avoid the intake of moisture. The pressure at the extruder head was set to 35 bar. Then the extruder 2 and spinning pump 3 were started. To achieve a constant throughput, the rotations per minute (RPM) of the spinning was constant and the RPM of the extruder 2 varied to keep the extruder head pressure at 35 bar. The purging was carried out for 1 hour to ensure that no traces of previous polymer were remaining in the machine.

(27) After purging and after a stable extrusion process was achieved, the filaments were produced and were cooled below the spinning head 4 (comprising a distribution plate and a spinneret) in the quenching unit 5 with air and collected in form of a bundle of filaments (multifilament), passed over the take-up roller 6, three duo rollers 7 and collected on a winder 9.

Production of the TPU-Multifilaments

(28) The TPU-granules were dried before processing in order to obtain a moisture content of less than 0.02% by weight. The polymers were dried in a vacuum oven at 80° C. and 10 mbar for about 12 hours.

(29) The dried TPU-granules were fed at room temperature through the hopper 1 under a constant flow of nitrogen into the extruder 2. The extruder used in the experiments had a single screw rotating in a heated cylinder. From the extruder 2 the melted TPU arrived in a spinning head 4 through a spinning pump 3. After leaving the spinning head the filaments were quenched in a quenching unit 5 and solidified by air cooling. The filaments were combined to a bundle (multifilament). The multifilament was stretched by pulling it through the duo rollers 7 and collecting it on the winder 9. The process parameters are described in the tables.

(30) TABLE-US-00002 TABLE 2 Process parameters for the production of non-inventive TPU multifilaments TPU used 3* 3* 4* 4* 4* 5* 5* 5* Experiment 1 2 3 4 5 6 7 8 Extruder temperature [° C.] Zone 1 170 170 170 170 170 185 185 185 Zone 2 190 190 180 180 180 205 205 205 Zone 3 200 200 190 190 190 215 215 215 Spinning pump 195 195 190 190 190 205 205 205 temperature [° C.] Spinning head 195 195 190 190 190 205 205 205 temperature [° C.] Spinning pump 5 5 5 5 5 15 15 15 speed; rotations per minute [RPM] Residence time 12.2 12.2 12.2 12.2 12.2 3.4 3.4 3.4 of the TPU in extruder and spinning head [min.] Roller speeds [m/min]: Take-up 24 59 35 35 46 45 50 51 roller 6 First duo roller 19 56 36 36 59 47 53 54 Second duo 36 79 46 57 80 57 65 65 roller Drawing 80 80 100 100 100 80 80 80 temperature [° C.] in the relaxation unit 8 Winding speed 34 71 46 55 76 61 68 68 in the winder 9 [m/min]

(31) TABLE-US-00003 TABLE 3 Process parameters for the production of inventive TPU multifilaments thermoplastic poly-urethane used 2 1 Experiment 1 2 3 4 5 6 Extruder temperature [° C.] Zone 1 195 195 195 195 195 200 Zone 2 200 200 200 200 200 200 Zone 3 215 215 215 215 215 200 Spinning pump 210 210 210 210 210 212 temperature [° C.] Spinning head 210 210 210 210 210 215 temperature [° C.] Spinning pump 15 15 15 15 15 10 speed in rotations per minute [RPM] Residence time of 3.4 3.4 3.4 3.4 3.4 6.1 the TPU in extruder and spinning head [min.] Roller speeds [m/min]: Take-up roller 6 110 90 80 80 80 73 First duo roller 110 92 85 85 85 73 Second duo roller 110 95 95 95 95 73 Drawing Room RT 60 70 80 RT temperature [° C.] in temperature the relaxation unit 8 (RT) Winding speed 110 97 97 97 97 73 [m/min]

(32) The following test methods were used:

(33) The fineness of the multifilaments was determined according to the DIN EN ISO 2060.

(34) The tensile strength and the elongation of the multifilaments was measured in accordance to the DIN EN ISO 2062.

(35) Table 4 describes the properties determined for the comparative TPU-multifilaments from Table 2.

(36) TABLE-US-00004 TABLE 4 Multifilament properties Example 1 2 3 4 5 6 7 8 Fineness [dtex] 510.48 226.24 397.73 371.15 269.98 783.88 671.55 687.87 Tensile strength [cN/tex] 2.82 5.18 3.39 3.33 4.16 4.88 5.06 4.69 Elongation [%] 206.2 197.9 279.17 263.21 193.84 329.51 307.64 298.52

(37) Table 5 describes the properties determined for the inventive TPU-multifilaments from Table 3.

(38) TABLE-US-00005 TABLE 5 Multifilament properties Example 1 2 3 4 5 6 Fineness [dtex] 395.47 441.97 385.43 426.33 374.4 277.23 Tensile 7.4 6.14 7.01 7.2 7.35 5.41 strength [cN/tex] Elongation [%] 401.4 330.4 401.7 405.6 413 460.9

(39) The TPU-multifilaments of the invention have a markedly better level of mechanical properties than the respective comparative multifilaments, this being particularly apparent from the tensile strength as well as the elongation at break.