Method for producing brominated and halohydrated polymers

Patent metadata

Field	Value
Publication number	US-10457751-B2
Application number	US-201615542424-A
Country	US
Kind code	B2
Filing date	Jan 27, 2016
Priority date	Jan 30, 2015
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

Conjugated diene polymers such as a styrene-butadiene copolymer are sequentially brominated by reaction with a quaternary ammonium tribromide or quaternary phosphonium tribromide and halohydrated by reaction with an N-haloimide compound. This produces a brominated and halohydrated polymer with very good thermal stability. The product is useful as a flame retardant in a variety of polymer systems.

First claim

What is claimed is:

1. A process for preparing a brominated and halohydrated polymer of at least one conjugated diene, comprising (a) reacting a starting polymer of at least one conjugated diene with a quaternary ammonium tribromide, quaternary phosphonium tribromide compound or both a quaternary ammonium tribromide and a quaternary phosphonium tribromide to brominate 50% to 98% of the conjugated diene repeating units in the starting polymer to form a partially brominated polymer and then (b) reacting the partially brominated polymer with an N-haloimide compound in the presence of water and a water-miscible solvent system for the partially brominated polymer to halohydrate at least a portion of the remaining conjugated diene repeating units and produce a brominated and halohydrated polymer.

2. The process of claim 1 wherein the N-haloimide is an N-halosuccinimide.

3. The process of claim 1 wherein the N-haloimide is an N-bromoimide.

4. The process of claim 1 wherein 65 to 95% of the conjugated diene units are brominated in step (a), 5 to 35% of the conjugated diene units are halohydrated in step (b), and 0 to 5% of the conjugated diene units are unreacted.

5. The process of claim 1 wherein 75 to 98% of the conjugated diene units are brominated in step (a), 2 to 25% of the conjugated diene units are halohydrated in step (b) and 0 to 5% of the conjugated diene units are unreacted.

6. The process of claim 1 , wherein in step (b) the concentration of the partially brominated polymer in the water-miscible solvent system is 2 to 25 weight percent based on the combined weight of partially brominated polymer and solvent system.

7. The process of claim 1 wherein in step (b), water is present in an amount from 0.25 to 1 parts by weight per part by weight of the solvent system.

8. The process of claim 1 wherein the starting polymer is a copolymer of styrene and butadiene having a weight average molecular weight of at least 20,000 by gel permeation chromatography against a polystyrene standard.

9. The process of claim 1 wherein the brominated and halohydrated polymer obtained from the process is a thermoplastic material that contains no more than 3 weight percent of gel material.

10. The process of claim 1 wherein the brominated and halohydrated is crosslinked in step (b) or in a subsequent step.

11. The process of claim 1 wherein the brominated and halohydrated polymer is formed into particles.

Assignees

• Dow Global Technologies Llc

Inventors

• Hull Jr John W
• Kram Shari
• Porter Michal Elizabeth
• Stobby William G

Classifications

• C08F8/20

  Halogenation · CPC title

• C08C19/12 Primary

  Incorporating halogen atoms into the molecule · CPC title

• C08F8/18

  Introducing halogen atoms or halogen-containing groups · CPC title

• C08J9/00

  Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof (mechanical aspects of shaping of plastics or substances in a plastic state for the production of porous or cellular articles B29C) · CPC title

• C08J2309/06

  Copolymers with styrene · CPC title