Process for preparing polyoxymethylene

Patent metadata

Field	Value
Publication number	US-2016115270-A1
Application number	US-201414894158-A
Country	US
Kind code	A1
Filing date	May 26, 2014
Priority date	May 29, 2013
Publication date	Apr 28, 2016
Grant date	—

Abstract

The patent application relates to a process for preparing polyoxymethylene by polymerization of a reaction mixture (R G ) which comprises at least one formaldehyde source and at least one initiator mixture (I G ), wherein the initiator mixture (I G ) comprises at least one polymerization initiator and at least one solvent of the general formula (I)
R 1 —O—[—R 3 —O—] m —R 2   (I),
where m is 1, 2, 3 or 4; R 1 and R 2 are each, independently of one another, C 3 -C 6 -alkyl; R 3 is C 1 -C 5 -alkylene.

First claim

1 . A process for preparing polyoxymethylene, comprising polymerizing a reaction mixture (R G ) which comprises a formaldehyde source and an initiator mixture (I G ), wherein the initiator mixture (I G ) comprises a polymerization initiator and a solvent of formula (I):
R 1 —O—[—R 3 —O—] m —R 2   (I),
wherein m is 1, 2, 3 or 4; R 1 and R 2 are each, independently of one another, C 3 -C 6 -alkyl; and R 3 is C 1 -C 5 -alkylene.

2 . The process according to claim 1 , wherein the formaldehyde source is selected from the group consisting of cyclic and linear formals.

3 . The process according to claim 1 , wherein
m is 1, 2, 3 or 4, R 1 and R 2 are both unsubstituted C 3 -C 6 -alkyl; and R 3 is unsubstituted C 1 -C 5 -alkylene.

4 . The process according to claim 1 , wherein the reaction mixture (R G ) further comprises a first comonomer (C-1).

5 . The process according to claim 4 , wherein the comonomer (C-1) is a cyclic ether of formula (II):

wherein
R 11 to R 14 are each, independently of one another, H, C 1 -C 4 -alkyl or halogen-substituted C 1 -C 4 -alkyl;
R 15 is a chemical bond, a (—CR 15a R 15b —) group or a (—CR 15a R 15b O—) group, where R 15a and R 15b are each, independently of one another, H, unsubstituted or at least monosubstituted C 1 -C 4 -alkyl in which the substituents are selected from among F, Cl, Br, OH and C 1 -C 4 -alkyl; and
n is 0, 1, 2 or 3.

6 . The process according to claim 4 , wherein the reaction mixture (R G ) comprises up to 50 mol %, based on the formaldehyde source, of the comonomer (C-1).

7 . The process according to claim 1 , wherein the polymerization initiator is a protic acid or a Lewis acid.

8 . The process according to claim 1 , wherein the polymerization initiator is added in an amount of from 0.0001 ppm to 1000 ppm, based on the reaction mixture (R G ).

9 . The process according to claim 1 , wherein the polymerization initiator is dissolved in the solvent (I) in a concentration of from 0.005% by weight to 5% by weight, based on a total weight of the initiator mixture (I G ).

10 . The process according to claim 1 , wherein the reaction mixture (R G ) further comprises a chain transfer agent.

11 . The process according to claim 10 , wherein the chain transfer agent is added in an amount of from 10 ppm to 10 000 ppm, based on the reaction mixture (R G ).

12 . The process according to claim 1 , wherein the reaction mixture (R G ) further comprises a second comonomer (C-2), which is a bifunctional compound of formula (III) or (IV):

wherein
Z is a chemical bond, an (—O—) group or an (—O—R 21 —O—) group, where R 21 is unsubstituted C 1 -C 8 -alkylene or C 3 -C 8 -cycloalkylene.

13 . A solvent of formula (I):
R 1 —O—[—R 3 —O—] m —R 2   (I),
wherein m is 1, 2, 3 or 4; R 1 and R 2 are each, independently of one another, C 3 -C 6 -alkyl; and R 3 is C 1 -C 5 -alkylene, and wherein the solvent is suitable as solvent for a polymerization initiator in the preparation of polyoxymethylene.

14 . A polyoxymethylene obtained by the process according to claim 1 .

15 . The polyoxymethylene according to claim 14 ,
wherein the polyoxymethylene has a degree of migration of the solvent for the polymerization initiator of less than 10 μg/kg.

Assignees

• Basf Se

Inventors

• Pottie Laurence
• Demeter Juergen
• Hermant Marie-Claire

Classifications

• C08G4/00

  Condensation polymers of aldehydes or ketones with polyalcohols; Addition polymers of heterocyclic oxygen compounds containing in the ring at least once the grouping —O—C—O— (of cyclic oligomers of aldehydes C08G2/00) · CPC title

• C08L59/04

  Copolyoxymethylenes · CPC title

• C08G2/18

  Copolymerisation of aldehydes or ketones · CPC title

• C08G2/22

  with epoxy compounds · CPC title

• C08G59/02

  Polycondensates containing more than one epoxy group per molecule · CPC title