Vinyl polymers prepared via suspension polymerization and methods thereof

Patent metadata

Field	Value
Publication number	US-9453083-B2
Application number	US-201313826705-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Mar 14, 2013
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

A method of producing vinyl polymer particles by suspension polymerization comprising: combining an aqueous media and a tricalcium phosphate to a reaction vessel; adding a pH stabilizing agent to the reaction vessel; adding a vinyl monomer to the reaction vessel; adding a peroxide initiator, e.g., which also generates CO 2 as a result of primary or secondary decomposition, to the reaction vessel; adding surfactant or a water soluble free radical initiator to generate surfactant in situ to the reaction vessel; maintaining the reactor contents at greater than or equal to 90° C. until a density of a dispersed phase becomes substantially equal to that of a continuous phase; adding a blowing agent to the reaction vessel; raising the temperature of the reaction vessel to greater than or equal to 100° C.; and collecting polymer particles having a particle size distribution.

First claim

We claim:

1. A method of producing vinyl polymer particles by suspension polymerization comprising:
adding a vinyl monomer, an aqueous media, a CO 2 generating initiator, tricalcium phosphate, and a pH stabilizing agent comprising one or both of trisodium phosphate and sodium bicarbonate to a reaction vessel under agitation to form a suspension having an initial pH of greater than or equal to 9; polymerizing, at a temperature of greater than or equal to 90° C., the vinyl monomer to result in polymerized particles with a size distribution;
wherein the adding the pH stabilizing agent comprises adding 0.01 wt % to 0.2 wt % of the pH stabilizing agent based on a total weight of the vinyl monomer.

2. The method of claim 1 , wherein the vinyl monomer comprises one or more of styrene, alpha-methylstyrene, p-methylstyrene, and p-ethylstyrene.

3. The method of claim 1 , wherein the CO 2 generating initiator comprises an organic peroxide.

4. The method of claim 1 , wherein the CO 2 generating initiator comprises one or more of dibenzoyl peroxide, dilauroyl peroxide, 2 tert-butylperoxy-benzoate, tert-butylperoxy-2-ethylhexyl carbonate, tert-butylperoxy-isopropyl carbonate, and tert-amylperoxy-2-ethylhexyl carbonate.

5. The method of claim 1 , wherein a water soluble initiator that comprises one or more of ammonium, potassium, and sodium persulfate is added to the reaction vessel to generate a surfactant in situ.

6. The method of claim 1 , wherein the particle size distribution has greater than or equal to 80% of the particles with sizes in the range of 0.4 to 0.8 mm, greater than or equal to 90% of the particles with sizes in the range of 0.8 to 1.1 mm, greater than or equal to 90% of particles with sizes in the range of 1.1 to 1.4 mm, or greater than or equal to 80% of particles with sizes in the range of 1.5 to 2.3 mm.

7. The method of claim 1 , wherein the polymerized particles comprise less than or equal to 1.5 wt % of particles having a size, as measured along a major axis, of less than 0.4 mm.

8. The method of claim 1 , wherein the polymerized particles do not comprise one or both of fines and oversize beads.

9. The method of claim 1 , further comprising the step of adding a blowing agent before, during, or after the step of polymerizing.

10. The method of claim 1 , wherein the polymerized particles are expandable.

11. The method of claim 1 , wherein the polymerized particles are expandable polystyrene.

12. The method of claim 1 , wherein the initial pH of the suspension is 9 to 11.

13. The method of claim 1 , further comprising monitoring a density of a dispersed phase and a density of a continuous phase; wherein the initial pH is maintained until the density of the of dispersed phase and the density of the continuous phase are within 1 to 5% of each other.

14. The method of claim 1 , wherein the initial pH is maintained until the density of a dispersed phase becomes substantially equal to that of a continuous phase.

15. The method of claim 1 , wherein the initial pH of the suspension is greater than 10 to 11.

Assignees

• Saudi Basic Ind Corp

Inventors

• Ahmed Syed Mehmood
• Hamdan Mohammed
• Hashmi Syed Azhar

Classifications

• C08J9/20

  by suspension polymerisation in the presence of the blowing agent · CPC title

• C08J9/02

  using blowing gases generated by the reacting monomers or modifying agents during the preparation or modification of macromolecules · CPC title

• C08J9/0023

  containing oxygen · CPC title

• C08J9/0066

  Use of inorganic compounding ingredients · CPC title

• C08J9/141

  Hydrocarbons · CPC title