Process for making a polymer polyol

Abstract

This invention relates to a continuous process for making a polymer polyol, the polymer polyol produced according to the said process and its applications.

Claims

1. A continuous process for making a polymer polyol, the polymer polyol comprising: particles of a thermoplastic styrene-acrylonitrile-copolymer (TP); at least one polyol (P); and a stabilizer (S); wherein the stabilizer (S) comprises: from 10 to 70% by weight, based on the sum of all components, of at least one polyol P2, and at least one polyol CSP which is a reaction product of at least one macromere M, styrene and acrylonitrile in P2, optionally with an initiator and/or a chain transfer agent, wherein the macromere comprises one or more polymerizable double bonds and one or more hydroxyl-terminated polyether tails, a content of the macromere M in the stabilizer (S) is between 30-70 wt %, based on the sum of all components of the stabilizer, wherein the polyol CSP comprises two or more OH groups, the process comprising: continuously feeding the TP, the P and the S to an extruder (E) having a plurality of process zones, preparing an initial dispersion of the TP, the P and the S in the extruder (E); continuously passing the initial dispersion obtained in the extruder into at least one rotor-stator device (RS) decoupled from the extruder comprising at least one rotor-stator combination; and cooling the rotor-stator treated dispersion below the glass transition temperature (T.sub.g) of the thermoplastic styrene-acrylonitrile-copolymer (TP) after passing all of the rotor-stators (RS) to obtain the polymer polyol, wherein in the preparation of the initial dispersion, TP is continuously fed into a first process zone Z1 of the extruder E, S is continuously fed into a second process zone Z2 or a later process zone, and P is continuously fed into a process zone following the process zone of addition of S, wherein the terms first and second refer to a direction of flow of the reaction mixture through the extruder E.

2. The process according to claim 1, wherein there is at least one process zone of the extruder E wherein no components are added between the zone of addition of the stabilizer S and the zone of addition of the polyol P.

3. The process according to claim 1, wherein P is fed into at least two different process zones after the zone of addition of the stabilizer S of the extruder E.

4. The process according to claim 1, wherein the extruder (E) is operated at a barrel temperature in the range of between 160 to 250 C. in at least one of the plurality of process zones.

5. The process according to claim 1, wherein a rotation speed of the extruder (E) is from 400 to 1200 rpm.

6. The process according to claim 1, further comprising removing volatile material in a stripping column or stripping-vessel after the rotor-stator device.

7. The process according to claim 1, wherein at least one of the at least one-level rotor-stator devices (RS) are operated at a set temperature of 160 to 250 C.

8. The process according to claim 1, wherein at least one of the rotor-stator devices (RS) has a circumferential speed in the range of 10 to 60 s.sup.1.

9. The process according to claim 1, wherein at least one of the rotor-stator devices comprises at least two rotor-stator combinations.

10. The process according to claim 9, wherein each single rotor-stator combination of the at least two rotor-stator combinations have differing teeth.

11. The process according to claim 1, wherein the polyol (P) is added to the extruder (E) at a temperature of above 100 C.

12. The process according to claim 1, wherein the stabilizer (S) is added to the extruder (E) at a temperature of above 100 C.

13. The process according to claim 1, wherein the polyol (P) is liquid at room temperature.

14. The process according to claim 1, wherein the polyol (P) is selected from the group of polyols consisting of polyols employed for slabstock foam applications and polyols employed for molded foam applications.

15. The process according to claim 1, wherein an average OH value of the polyol (P) is between 20 and 300 mg KOH/g.

16. The process according to claim 1, wherein an average functionality of the polyol (P) is from 2 to 6.

17. The process according to claim 1, wherein an average particle size of the product according to D50 is below 25 m, as determined by static laser diffraction.

18. The process according to claim 1, wherein the polyol P2 contained in the stabilizer S is a polyether polyol (PEOL).

19. The process according to claim 1, wherein an average molecular weight of the macromere M is from 1000 to 50000 g/mol.

20. The process according to claim 1, wherein the macromere M is obtained by reaction of 1,1-dimethyl meta isopropenyl benzyl isocyanat (TMI) with a polyether polyol PM, selected from the group consisting of three- and sixfunctional polyether polyols, the reaction optionally conducted in the presence of a Lewis acid catalyst.

21. The process according to claim 1, wherein a ratio of styrene to acrylonitrile in the polyol CSP is greater than 1:1.

22. The process according to claim 1, comprising a chain transfer agent and an initiator in production of the stabilized S wherein the chain transfer agent is selected from the group consisting of dodecane thiol, isopropanol and 2-butanol, and the initiator is selected from the group consisting of azoisobutyro nitrite (AIBN) and Dimethyl 2,2-azobis(2-methylpropionate).

23. The process according to claim 1, wherein a ratio of styrene to acrylonitrile in the styrene-acrylonitrile-copolymer (TP) is greater than 1:1.

24. The process according to claim 1, wherein the dispersion is cooled below the T.sub.g of the thermoplastic styrene-acrylonitrile-copolymer (TP) within a maximum time range of four hours after passing all of the rotor-stator devices (RS).

25. The process according to claim 1, wherein the dispersion is cooled to a temperature of equal to or less than 60 C., within a maximum time range of four hours after passing all of the rotor-stator devices (RS).

26. The process according to claim 1, wherein a particle size distribution of the polymer polyol is monomodal, bimodal or multimodal.

27. The process according to claim 9, wherein the first rotor-stator combination has coarse teeth, the next rotor-stator combination in the flow direction has medium fine teeth, and the third rotor-stator combination in the flow direction has fine teeth.

Description

EXAMPLE 1

(1) A recipe comprised of the 40 wt % of SAN, 15 wt % stabilizer 1 and 45 wt % Lupranol 2095 was used. All the SAN was fed into the extruder in zone 1, all the stabilizer was injected into extruder zone 3 and all the Lupranol was injected into extruder zone 4. The respective extruder processing parameters such as barrel temperature profile, screw rotation speed and throughput can be found in Table 2. The extruder set-up used is schematically represented in FIG. 2. The sample collected after the extruder had a particle size of D50=8,955 m, D90=88,658 m. The sample collected after the rotor-stator device had a particle size of D50=2,089 m, D90=8,469.

(2) The viscosity of the sample collected after rotor stator device was 6837 mPas determined at 25 C. in accordance with DIN EN ISO 3219 from 1994.

(3) This example shows the important influence of the rotor-stator device in order to obtain small and uniform particles. By using a rotor-stator device the particle size D90 could be reduced by a factor higher than 10. Dosing of the polyol after the PFS was observed to be beneficial for efficient stabilization.

EXAMPLE 2 (INFLUENCE OF ROTOR STATOR AND DOSING POSITION)

(4) A recipe comprised of the 40 wt % of SAN, 15 wt % stabilizer 1 and 45 wt % Lupranol 2095 was used. SAN was fed into the extruder in zone 1, all the stabilizer was injected into extruder zone 3 and Lupranol 2095 was injected into extruder zone 7. The respective extruder processing parameters such as barrel temperature profile, screw rotation speed and throughput can be found in Table 2. The extruder set-up used is schematically represented in FIG. 2.

(5) The sample collected after the extruder had a particle size of D50=5,455 m, D90=14,852 m. The sample collected after the rotor-stator device had a particle size of D50=1,410 m, D90=2,116.

(6) The viscosity of the sample collected after rotor stator device was 10266 mPas determined at 25 C. in accordance with DIN EN ISO 3219 from 1994.

(7) Recipe & Parameters

(8) Cavitron speed: 265 Hz

(9) Cooling temp: 60 C.

(10) This example shows once again the important influence of the rotor-stator device in order to obtain small and uniform particles. Alteration of the dosing position of the carrier polyol leads to a significant decrease in particle size. Dosing of the polyol at a later stage (zone 7 instead of zone 4) of the extruder may be important for obtaining smaller particles This difference is observed after the extruder in comparison to example 1 and consequently after the rotor-stator device. By dosing the Lupranol 2095 at a later stage in the extruder the particle size D90 after extruder could be reduced by a factor of 6 compared to example 1 and by using a rotor-stator device the particle size D90 could be reduced again by a factor of 7.

EXAMPLE 3 (SPLIT POLYOL DOSING)

(11) The sample collected after the rotor-stator device had a particle size of D50=1,343 m, D90=1,949.

(12) The viscosity of the sample collected after rotor stator device was 7145 mPas determined at 25 C. in accordance with DIN EN ISO 3219 from 1994

(13) Recipe & Parameters

(14) Cavitron speed: 265 Hz

(15) Cooling temp: 60 C.

(16) A recipe comprised of the 41 wt % of SAN, 12 wt % stabilizer 1 and 47 wt % Lupranol 2095 was used. SAN was fed into the extruder in zone 1, all the stabilizer was injected into extruder zone 3. Lupranol 2095 dosing was split between extruder zones 4 and 7 with 30 wt % and 17 wt % respectively. The respective extruder processing parameters such as barrel temperature profile, screw rotation speed and throughput can be found in Table 2. The extruder set-up used is schematically represented in FIG. 2.

(17) This example shows that the dosing of polyol can be split up in different parts of the extruder, in this case with a decrease in particle size distribution. As mentioned above, it is important that the polyol is dosed after the stabilizer. By using a split polyol dosing the particle size D90 could be reduced by 9%, compared to example 2.

(18) Some figures have been added to illustrate some aspects of the present invention.

(19) FIG. 1 shows an exemplary set-up of devices for the inventive process. Optionally, a stripping column is used to remove residual volatile components, like styrene or acrylonitrile. In a preferred embodiment of the inventive process, at least one stripping column is used. Thus, the amount of residual styrene in the product may be reduced to levels below 20 ppm and the amount of acrylonitrile below 5 ppm. Optionally at least one filter can be installed.

(20) FIG. 2 shows a preferred embodiment of the inventive process, where in the first place, SAN is added to the extruder (E) into the first process zone, and then, later on, stabilizer (S) and polyol (P) are added successively into separate process zones of the extruder (E).

(21) TABLE-US-00002 TABLE 2 Process parameters used in extrusion step for examples given above. (GK 3496-024-01: example 1; GK 3496-024-02: example 2; GK 3496-030-01: example 3) Barrel set temperature Through- Through- Through- Through- Zone put put put put Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone 11 Polymer Stabilizer Polyol Polyol Experiment 1 2 3 4 5 6 7 8 9 10 Head RPM Zone 1 Zone 3 Zone 4 Zone 7 number [ C.] [ C.] [ C.] [ C.] [ C.] [ C.] [ C.] [ C.] [ C.] [ C.] [ C.] [min.sup.1] [kg/h] [kg/h] [kg/h] [kg/h] GK3496- 30 230 210 210 190 190 190 190 190 190 190 500 2.4 0.9 2.7 030-01 GK3496- 30 230 210 210 190 190 190 190 190 190 190 500 2.4 0.9 2.7 024-02 GK3496- 30 230 210 210 190 190 190 190 190 190 190 500 4,920 1.44 3.60 2,040 024-01

(22) The polymer polyol obtainable by the inventive process may be used for the production of polyurethanes, in particular for flexible polyurethane foams.

(23) Polymer polyols made according to the present invention may be reacted with polyisocyanate. The polyisocyanates may be selected from the group comprising aliphatic, cycloaliphatic, arylaliphatic and aromatic isocyanates. Among them, aromatic polyisocyanates are preferred. Examples of suitable aromatic isocyanates include 2,4-, 2,6-isomers of toluene diisocyanate (TDI), 4,4-, 2,4 and 2,2-isomers of diphenylmethane diisocyante (MDI), or mixtures thereof. Optionally, a blowing agent may also be used.

(24) The polymer polyols obtainable by the inventive process may be used in a variety of applications. Inter alia, the may be used for the production of polyurethane (PU) foams, like microcellular foams, flexible foams, formed flexible foams, viscoelastic foams, rigid foams for construction or insulation applications, or PU elastomers, thermoplastic polyurethanes (TPU), PU coatings, PU sealants, PU adhesives, surfactants, lubricants, dispersants, concrete liquefiers, as seed or starting material for the production of polymer polyols, as seed or starting material for aqueous polymer dispersions, as seed or starting material

(25) In one embodiment, the polymer polyols obtainable by the inventive process are used for the production of flexible polyurethane foams. Preferred applications of the polyurethane foams include footware applications and applications in the car sector and furniture, for example car seats.