Nanocellular foam with solid flame retardant

Patent metadata

Field	Value
Publication number	US-9822230-B2
Application number	US-201515109935-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	Mar 28, 2014
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

Prepare nanofoam by (a) providing an aqueous solution of a flame retardant dissolved in an aqueous solvent, wherein the flame retardant is a solid at 23° C. and 101 kiloPascals pressure when in neat form; (b) providing a fluid polymer composition selected from a solution of polymer dissolved in a water-miscible solvent or a latex of polymer particles in a continuous aqueous phase; (c) mixing the aqueous solution of flame retardant with the fluid polymer composition to form a mixture; (d) removing water and, if present, solvent from the mixture to produce a polymeric composition having less than 74 weight-percent flame retardant based on total polymeric composition weight; (e) compound the polymeric composition with a matrix polymer to form a matrix polymer composition; and (f) foam the matrix polymer composition into nanofoam having a porosity of at least 60 percent.

First claim

The invention claimed is:

1. A process for preparing nanofoam comprising the following steps:
(a) providing an aqueous solution of a flame retardant dissolved in an aqueous solvent, wherein the flame retardant is a solid at 23° C. and 101 kiloPascals pressure when in neat form;
(b) providing a fluid polymer composition selected from a solution of polymer dissolved in a water-miscible solvent or a latex of polymer particles in a continuous aqueous phase;
(c) mixing the aqueous solution of flame retardant with the fluid polymer composition to form a mixture;
(d) removing water and, if present, solvent from the mixture to produce a polymeric composition having flame retardant present at a concentration of less than 74 weight-percent based on total polymeric composition weight;
(e) compounding the polymeric composition with a matrix polymer to form a matrix polymer composition; and
(f) foaming the matrix polymer composition into nanofoam having a porosity of at least 60 percent.

2. The process of claim 1 , further characterized by the flame retardant in step (a) being a halogen-free flame retardant.

3. The process of claim 1 , further characterized by the flame retardant being aluminum tris (2-(diethyoxyphosphoryl) acetate).

4. The process of claim 1 , where the fluid polymer composition of step (b) is a latex of polymer particles in a continuous aqueous phase.

5. The process of claim 4 , further characterized by the polymer particles of the latex in step (b) being miscible with the matrix polymer of step (e).

6. The process of claim 4 , further characterized by the polymer particles of the latex and the matrix polymer being selected from acrylate polymers.

7. The process of claim 4 , further characterized by removing water and, if present, solvent in step (d) at pressure and temperature conditions under which the flame retardant is a solid and the polymer particles in the latex do not indistinguishably coalesce.

8. The process of claim 1 , further characterized by foaming the matrix polymer composition in step (f) by pressurizing a mixture of carbon dioxide and the matrix polymer composition under temperature and pressure conditions so that the carbon dioxide dissolves in the polymer matrix to form a foamable polymer composition and then depressurizing the foamable polymer composition at a rate of at least 100 megaPascals per second to cause the foamable polymer composition to foam.

Assignees

• Dow Global Technologies Llc

Inventors

• Chen Liang
• Kelly-Rowley Anne M
• Bunker Shana P
• Costeux Stéphane

Classifications

• C08J9/0061

  characterized by the use of several polymeric components · CPC title

• C08J2203/06

  CO2, N2 or noble gases · CPC title

• C08J3/215 Primary

  at least one additive being also premixed with a liquid phase · CPC title

• C08J9/0004

  Use of compounding ingredients, the chemical constitution of which is unknown, broadly defined, or irrelevant · CPC title

• C08J2201/024

  Preparation or use of a blowing agent concentrate, i.e. masterbatch in a foamable composition · CPC title