Isocyanate prepolymer composition and crosslinked polyurethane prepared therefrom

Abstract

An isocyanate prepolymer composition and a crosslinked thermoplastic polyurethane composition are disclosed, preferably in the form of a fiber. Also disclosed is the process for preparing said prepolymer composition and crosslinked thermoplastic polyurethane. Both of the isocyanate prepolymer composition and crosslinked thermoplastic polyurethane show improved properties.

Claims

1. A crosslinked thermoplastic polyurethane composition, comprising a reaction product of the following components: a thermoplastic polyurethane; an isocyanate prepolymer composition; and optionally, a supplementary substance, wherein the isocyanate prepolymer composition comprises: an isocyanate prepolymer which is a reaction product of diphenylmethane diisocyanate and a polyester polyol consisting of a reaction product of adipic acid and 2-methyl-1,3-propanediol; and a polymethylene polyphenyl polyisocyanate (PMDI) with chemical structure shown below: ##STR00007## and optionally, a plasticizer, and wherein an average functionality obtained with the isocyanate prepolymer composition is between 2.1 and 3.

2. The crosslinked thermoplastic polyurethane composition of claim 1, which is in the form of a fiber.

3. The crosslinked thermoplastic polyurethane composition according to claim 1, wherein the PMDI has an average functionality of 2 to 6.

4. The crosslinked thermoplastic polyurethane composition of claim 1, wherein a mole ratio of the polyester polyol to the diphenylmethane 4,4-diisocyanate is from 1/1.2 to 1/3.

5. A process for preparing the crosslinked thermoplastic polyurethane composition of claim 1, the process comprising reacting the following components: the thermoplastic polyurethane; the isocyanate prepolymer composition; and optionally, a supplementary substance.

6. The process of claim 5, wherein the PMDI, the plasticizer, or both, is added to the thermoplastic polyurethane, the isocyanate prepolymer and/or a mixture of the isocyanate prepolymer and the thermoplastic polyurethane.

7. The process of claim 5, wherein the PMDI, the plasticizer, or both, is mixed with starting materials of the isocyanate prepolymer, or if the plasticizer is present in said composition, the isocyanate prepolymer is first mixed with the plasticizer, and then with the PMDI.

8. A process for preparing the crosslinked thermoplastic polyurethane composition of claim 1, the process comprising: (1) melting the thermoplastic polyurethane in a extruder at a temperature of 180 C. to 220 C.; (2) adding the isocyanate prepolymer composition according to claim 1 to a molten thermoplastic polyurethane from (1) and mixing a resulting mixture to form a melt; and (3) extruding the melt through a spinneret heated at 190 C. to 230 C. to obtain a melt-spun elastic fiber.

9. The process of claim 8, further comprising: (4) spraying finish oil on the fiber; (5) winding up a resulting fiber through a roller at a line speed of 100 to 1000 m/min; and (6) storing the fiber for at least 15 h at 80 C.

Description

EXAMPLE 1

(1) Preparation a polyester polyol with average functionality 2.2 and number average molecular weight of 1 kg/mol.

(2) 657.8 g (4.51 mol) adipic acid, 477.5 g (5.31 mol) 2-methyl-1,3-propanediol and 26.8 g (0.2 mol)trimethylolpropane were stirred at 225 C.-230 C. in a 2 liter three-necked flask equipped with a mechanical stirrer, thermometer, and a distillation head. After the rate of distillation significantly decreased and the mixture became clear, the distillation was continued under reduced pressure (33 kPa) until an acid number less than 0.3 mg KOH/g detected in accordance with ASTM D-1045 was obtained.

(3) The following examples 2-8 are for preparing isocyanate prepolymers and the compositions thereof.

EXAMPLE 2 (COMPARATIVE EXAMPLE)

(4) 2000 g polyester diol having a number average molecular mass of 2 kg/mol, obtained from adipic acid, 2-methyl-1,3-propanediol and 1,4-butanediol, with the latter two in the mass ratio of 1:1 (commercially available from BASF as Lupraphen 6610/1), was added to 500 g diphenylmethane-4,4-diisocyanate with mechanical stirring and the reaction mixture temperature was controlled between 50 C.-65 C. After all the polyester diol was added, the reaction mixture was reacted at 70 C. for additional 3 hours.

EXAMPLE 3 (COMPARATIVE EXAMPLE)

(5) 12.1 g trimethylolpropane was mixed with 735.5 g Lupraphen 6610/1, then this mixture was added to 252.4 g diphenylmethane-4,4-diisocyanate with mechanical stirring and the reaction mixture temperature was controlled between 50 C. and 65 C. After adding all the polyol, the reaction mixture temperature was kept at 70 C. for additional 3 hours.

EXAMPLE 4 (COMPARATIVE EXAMPLE)

(6) 600 g polyol made according to example 1 was added to 346 g diphenylmethane-4,4-diisocyanate with mechanical stirring and the reaction mixture temperature was controlled between 50 C. and 65 C. After adding all the polyol, the reaction mixture temperature was kept at 70 C. for additional 3 hours.

EXAMPLE 5 (INVENTIVE EXAMPLE)

(7) 519 g diphenylmethane-4,4-diisocyanate and 157.7 g 1,2-cyclohexane dicarboxylic acid diisononyl ester were mixed, to this mixture 905.9 g polyol made according to example 1 was added under mechanical stirring. The reaction mixture temperature was controlled between 50 C. and 65 C. After adding all the polyol, the reaction mixture temperature was kept at 70 C. for additional 3 hours.

EXAMPLE 6 (INVENTIVE EXAMPLE)

(8) 500 g isocyanate prepolymer composition made according to example 5 was mixed with 167 g PMDI (BASF, Lupranate M20S) at 60 C.

EXAMPLE 7 (INVENTIVE EXAMPLE)

(9) 500 g isocyanate prepolymer composition made according to example 5 was mixed with 250 g polymethylene polyphenyl polyisocyanate (BASF, Lupranate M20S) at 60 C.

EXAMPLE 8 (INVENTIVE EXAMPLE)

(10) 500 g isocyanate prepolymer composition made according to example 5 was mixed with 500 g polymethylene polyphenyl polyisocyanate with a functionality about 2.7 (BASF Lupranate M20S) at 60 C.

(11) TABLE-US-00001 TABLE 1 viscosity of isocyanate prepolymers/prepolymer compositions Examples 2(C) 3(C) 4(C) 5 6 7 8 Viscosity 5.0 8.5 9.0 5.5 2.0 1.3 0.8 (Pa*s at 75 C.)

(12) It is evident from table 1 that the plasticizer reduces the viscosity of the isocyanate prepolymer composition and the viscosity is further reduced by additional PMDI (BASF SE, Lupranate M20S).

EXAMPLES 9-15

(13) In these examples, melt-spun elastic fiber were produced by the following process:

(14) (1) melting a thermoplastic polyurethane, e.g. BASF TPUs such as BASF Elastollan 2280A10 which is made from 4,4-MDI, 1,4-butanediol, polytetramethylene ether glyol with number molecular weight 1000 g/mol, and Lupraphen 6610/1, in a single screw extruder at a temperature of 190 C. or as indicated;

(15) (2) adding the prepolymer or prepolymer composition obtained from Examples 2-8 into the molten TPU from step (1), and mixing them to form a melt;

(16) (3) extruding the melt through a spinneret which is heated at 200 C. or as indicated to obtain a melt-spun elastic fiber;

(17) (4) spraying finish oil on the fiber, and the finish oils was silicone oil;

(18) (5) winding up the fiber through a roller at a line speed of 500 m/min;

(19) (6) storing the fibers for 15 h at 80 C. for better comparability.

EXAMPLE 9 (COMPARATIVE EXAMPLE)

(20) 880 g Elastollan 2280A10 with 120 g isocyanate prepolymer from Example 2, with a spinneret temperature 200 C.

EXAMPLE 10 (INVENTIVE EXAMPLE)

(21) 880 g Elastollan 2280A10 with 120 g isocyanate prepolymer from Example 3, with a spinneret temperature 210 C.

EXAMPLE 11 (INVENTIVE EXAMPLE)

(22) 880 g Elastollan 2280A10 with 120 g isocyanate prepolymer from Example 4, with a spinneret temperature 209 C.

EXAMPLE 12 (INVENTIVE EXAMPLE)

(23) 870 g Elastollan 2280A10 with 130 g isocyanate prepolymer from Example 5, with a spinneret temperature 205 C.

EXAMPLE 13 (INVENTIVE EXAMPLE)

(24) 940 g Elastollan 2280A10 with 60 g isocyanate prepolymer composition from Example 6, with a spinneret temperature 198 C.

EXAMPLE 14 (INVENTIVE EXAMPLE)

(25) 940 g Elastollan 2280A10 with 60 g isocyanate prepolymer composition from Example 7, with a spinneret temperature 201 C.

EXAMPLE 15 (INVENTIVE EXAMPLE)

(26) 940 g Elastollan 2280A10 with 60 g isocyanate prepolymer composition from Example 8, with a spinneret temperature 204 C.

EXAMPLE 16 (COMPARATIVE EXAMPLE)

(27) One 20D melt-spun elastic fiber commercially available from the market made by Jiangsu Nanhuanghai Industry commerce Co., Ltd.

(28) TABLE-US-00002 TABLE 2 processing condistions and properties of the fiber products Examples 9(C)-2.sup.c 10-3 11-4 12-5 13-6 14-7 15-8 16(C) Spinneret 200 210 209 205 204 201 198 N.A. temperature ( C.).sup.a Kofler melt 198 220 220 215 230 240 250 200 temperature ( C.).sup.b .sup.athe spinneret temperatures can be varied due to the design of melt spinning equipments. .sup.bthe kofler melting temperature refer to the temperature that the fiber changes from solid to liquid after it was placed on the hot metal strip of the kofler bench for 1 min. .sup.c9-2 refers to example 9 with the isocyanate prepolymer from example 2.

(29) From table 2, it is evident that the fibers with the isocyanate prepolymer compositions as required by the invention (Examples 10 to 15) show improved high temperature resistance than the fiber made from TPU and isocyanate prepolymer with functionality=2. The fibers disclosed also show improved high temperature resistance than the commercial available melt-spun elastic fiber.