STABILIZER FOR POLYMER POLYOL PRODUCTION PROCESSES

Abstract

This invention relates to a stabilizer for polymer polyol production processes, its production and use.

Claims

1. A stabilizer (S), comprising 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 comprises 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 a content of macromere M of the stabilizer (S) is between 35 to 54 wt %, based on the sum of all components, and wherein an overall content of styrene of the stabilizer (S) is between 4 to 15 wt %, and/or an overall content of acrylonitrile of the stabilizer (S) is between 2 to 7 wt, and wherein the macromere M is obtained by reacting 1,1-dimethyl meta isopropenyl benzyl isocyanate (TMI) with a polyether polyol PM, optionally in the presence of a Lewis acid catalyst.

2. The stabilizer (S) according to claim 1, consisting of one or two polyols P2 and one or two polyols CSP which comprise the reaction product of at least one macromere M styrene and acrylonitrile in P2, optionally with an initiator selected from the group consisting of azo initiators and peroxide initiators, and/or a chain transfer agent selected from the group consisting of dodecane thiol, isopropanol and 2-butanol.

3. The stabilizer (S) according to claim 1, consisting of one or two polyols P2 one or two polyols CSP which consist of the reaction product of a macromere M, styrene and acrylonitrile in P2.

4. The stabilizer (S) according to claim 1, wherein the macromere M has an average molecular weight Mn of from 1000 to 50000 g/mol.

5. The stabilizer (S) according to claim 1, wherein the macromere M has from 0.2 to 1.2 polymerizable ethylenically unsaturated groups per molecule in average and/or from 2 to 8 hydroxyl groups per molecule.

6. The stabilizer (S) according to claim 1, wherein the polyether polyol PM is selected from the group consisting of three- and six-functional polyether polyols.

7. The stabilizer (S) according to claim 1, wherein the ratio of styrene to acrylonitrile is greater than 1:1.

8. The stabilizer (S) according to claim 1, wherein a viscosity of the stabilizer is between 1000 and 100000 mPas at 25 C., determined according to DIN EN ISO 3219 and a shear rate of 100 1/s.

9. The stabilizer (S) according to claim 1, wherein an overall content of polyol P2 of the stabilizer (S) is 20 to 70 wt %.

10. The stabilizer (S) according to claim 1, comprising no additional solvent.

11. A process for the production of the stabilizer (S) according to claim 1, comprising free radical polymerization of styrene, acrylonitrile and at least one macromere M in the presence of at least one polyol P2, wherein the macromere M is obtained by reacting 1,1-dimethyl meta isopropenyl benzyl isocyanate (TMI) with a polyether polyol PM, optionally in the presence of a Lewis acid catalyst.

12. The process according to claim 11, wherein at least one chain transfer agent is present during the free radical polymerization.

13. The process according to claim 12, wherein at least one chain transfer is selected from the group consisting of dodecane thiol, isopropanol and 2-butanol.

14. The process according to claim 12, wherein less than 5% by weight of the chain transfer agents are present, relative to the weight of the entire reaction mixture.

15. The process according to claim 11, wherein a reaction temperature is between 80 and 150 C., and/or the reaction takes between 10 min and 300 mm.

16. The process according to claim 11, wherein at least one initiator is present during the free radical polymerization.

17. The process according to claim 16, wherein less than 1% by weight of the initiators are present, relative to the weight of the entire reaction mixture.

18. A process of stabilizing a polymer polyol dispersion produced by melt emulsification, comprising adding the stabilizer (S) according to claim 1 to the dispersion.

19. A process for producing a polymer polyol dispersion by melt emulsification, comprising adding the stabilizer (S) according to claim 1 to the dispersion.

20. The process according to claim 19, wherein the obtained polymer polyol dispersion has a solid content of 10% to 50%, and/or a viscosity of 1000 to 20000 mPas at 25 C., and/or an average particle size of D50 <50 m.

21. (canceled)

Description

EXAMPLES

[0051] In the following sections, some experimental examples are given in order to illustrate some aspects of the present invention.

General Procedure for Synthesizing a Stabilizer

[0052] A glass reactor was charged with a carrier polyol, optionally already in the beginning a macromere or a mixture of macromeres, optionally acrylonitrile, optionally styrene, optionally a chain transfer agent and heated to 125 C. A mixture of carrier polyol, initiator, styrene, acrylonitrile and macromere or a mixture of macromeres were added over 100 minutes. The reaction mixture was stirred for another 20 minutes at 125 C. The mixture was subsequently evacuated under reduced pressure for 120 minutes at 125 C. to remove residual monomers. The obtained stabilizers were characterized and used without further purification.

[0053] The composition of representative stabilizers obtained by this procedure are shown in table x. All amounts are given in weight %. All experiment were carried out by using 0,5 weight % of azo initiator (Dimethyl 2,2-azobis(2-methylpropionate) and 0,4% of a thiol containing chain transfer agent. The weight percentages given in this section refer to the final product (i. e. the stabilizer).

TABLE-US-00001 TABLE 1 carrier OH- styrene macromere macromere Polyo, value in acrylonitrile A in B in in in mg viscosity experiment weight in weight weight weight weight KOH/ in No. % %. % % % g mPas 1 7.8 4.2 50 0 37 25.3 14990 2 5.5 4 0 41 48.5 25.1 9913 3 17.3 8.8 0 42 31.3 20.4 39400 4 3.64 1.86 56.64 0 37.28 23.2 9040 5 7.8 4.2 32 16 39 23.7 25345 6 10.3 5.5 42.2 21.1 19.8 46.7 Viscosity not measurable at RT, 18285 @ 75 C. 7 7.8 4.2 16 0 70 29.8 2300

[0054] The residual portion (rest when adding up to 100% by weight) is made up of the initiator(s) and the chain transfer agent(s).

Production of Polyol Dispersion

[0055] The following dispersions were obtained by using commercially available styrene-acrylonitrile copolymer types with different compositions of styrene and acrylonitrile. For example Starex types from Samsung, Luran types from Styrolution, Lustran types from lneos can be used. A round bottom-flasked equipped with a stirrer and a nitrogen inlet was charged with 200 g of the SAN type given in table x and 50 g of the selected stabilizer and heated to 245 C. under nitrogen atmosphere. The mixture was stirred for 15 minutes at this temperature. Lupranol 2095 was heated to 245 C. and added with vigorous stirring. The mixture was stirred for additional 30 minutes after addition and then cooled to RT. The particle size was determined by light scattering as described before. The particle size is used as an indicator for the efficiency of the stabilizer system.

TABLE-US-00002 SAN composition Styrene to particle size Dispersion Stabilizer acrylonitrile D50 in No. No. (weight ratio) Micrometer 1 1 65/35 1.9 2 1 76/24 3.7 3 2 65/35 2.5 4 3 65/35 140.4 5 4 65/35 27.7 6 5 65/35 2.18 7 5 76/24 2.2 8 7 65/35 No phase stable product obtained .fwdarw. insufficient stabilization

[0056] Examples 1 to 3 in comparison to example 4 show that the ratio between, styrene, acrylonitrile, macromere or macromere mixtures and carrier polyol which was used for the synthesis of the stabilizers is important for efficient stabilization of the produced dispersions. Stabilizer 3 used in example 4 shows that a high amount of styrene and acrylonitrile which was used to produce the stabilizers leads to ineffective stabilization of the dispersions obtained with these products. Example 5 which used stabilizer 4 and example 8 which uses stabilizer 7 shows that the amount of used macromere is critical to obtain efficient stabilizer systems.

[0057] The ratio between the monomers styrene and acrylonitrile which were used to produce the stabilizer does not necessarily have to match the ratio of the used SAN material to obtain stable dispersion. The stabilizer used in example 2 and 7 had a styrene to acrylonitrile ratio of 1.86 to 1, the SAN used as a dispersed phase had a composition of 3.16 to 1. In both cases very stable dispersion with small particle sizes could be obtained. Stabilizer 6 could not be used to prepare dispersion because of the high viscosity of this stabilizer. Handling of these highly viscous stabilizers under normal conditions is not possible.