Thermoplastic foams and method of forming them using nano-graphite

Patent metadata

Field	Value
Publication number	US-10184037-B2
Application number	US-201615147159-A
Country	US
Kind code	B2
Filing date	May 5, 2016
Priority date	Nov 26, 2003
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

Rigid foam insulating products and processes for making such insulation products are disclosed. The foam products are formed from a polymer, a blowing agent, and nano-graphite. The nano-graphite has a size in at least one dimension less than about 100 nm and, in exemplary embodiments may be an intercalated, expanded nano-graphite. In addition, the nano-graphite may include a plurality of nanosheets having a thickness between about 10 to about 100 nanometers. The nano-graphite acts as a process additive to improve the physical properties of the foam product, such as thermal insulation and compressive strength. In addition, the nano-graphite in the foam controls cell morphology and acts as a nucleating agent in the foaming process. Further, the nano-graphite exhibits overall compound effects on foam properties including improved insulating value (increased R-value) for a given thickness and density and improved ultraviolet (UV) stability.

First claim

What is claimed is:

1. An extruded polymeric foam material comprising:
a polymer comprising polystyrene, wherein the polymer has a weight-average molecular weight from 30,000 to 500,000;
a blowing agent composition comprising carbon dioxide; and
from 0.05 to 5 wt. % of a nano-graphite material based upon the total weight of the polymer,
wherein the extruded polymeric foam material comprises cell walls and struts that define a plurality of cells,
wherein at least 90% of the cells are closed cells, and
wherein a ratio r of the cell dimension in an extrusion direction to the cell dimension in a thickness direction satisfies one of: r<1 and 1<r≤1.54.

2. The extruded polymeric foam material of claim 1 , wherein the nano-graphite material is selected from the group consisting of nanosheets of graphite, intercalated nano-graphite, exfoliated nano-graphite, and expanded nano-graphite.

3. The extruded polymeric foam material of claim 1 , wherein the blowing agent composition further comprises at least one blowing agent selected from the group consisting of aliphatic hydrocarbons having 1-9 carbon atoms, fully or partially halogenated aliphatic hydrocarbons having 1-4 carbon atoms, methane, ethane, propane, n-butane, isobutane, isopentane, n-pentane, isopentane, neopentane, cyclopentane, methanol, ethanol, n-propanol, and isopropanol.

4. The extruded polymeric foam material of claim 3 , wherein the blowing agent composition further comprises at least one blowing agent selected from the group consisting of 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-difluoroethane (HFC-152a), water, and ethanol.

5. The extruded polymeric foam material of claim 1 , wherein the nano-graphite has a size, in at least one dimension, of less than 100 nanometers.

6. The extruded polymeric foam material of claim 1 , wherein the cells have a median cell size of less than 150 microns.

7. The extruded polymeric foam material of claim 1 , wherein the extruded polymeric foam material is a rigid insulating foam board.

8. The extruded polymeric foam material of claim 7 , wherein the foam board has a density from 1.2 pcf to 5 pcf.

9. The extruded polymeric foam material of claim 7 , wherein the foam board has a thickness from ⅛ inch to 12 inches.

10. The extruded polymeric foam material of claim 1 , wherein the extruded polymeric foam material is a foam board having an R-value per inch from 3 to 8.

Assignees

• Owens Corning Intellectual Capital Llc

Inventors

• Breindel Raymond
• Loh Roland
• Rynd Joseph P
• Delaviz Yadolah
• Polasky Mark E

Classifications

• C08J9/008 Primary

  Nanoparticles · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• Y10T428/249986

  Void-containing component contains also a solid fiber or solid particle · CPC title

• C08J2325/06

  Polystyrene · CPC title

• C08J2433/00

  Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers · CPC title