Low density microspheres

Patent metadata

Field	Value
Publication number	US-10808094-B2
Application number	US-201515525656-A
Country	US
Kind code	B2
Filing date	Nov 11, 2015
Priority date	Nov 11, 2014
Publication date	Oct 20, 2020
Grant date	Oct 20, 2020

Abstract

Low-density thermoplastic expandable microspheres are disclosed. Various low-density structures, in particular, sandwich panels, based on foam prepared from the low-density microspheres, are also disclosed. Process of preparing low-density polymeric microspheres, per se, and the corresponding low-density structures, based on the microsphere foam, are also disclosed.

First claim

What is claimed is:

1. A composition of matter comprising a foam, said foam comprising polymeric microspheres, said polymeric microspheres further being expanded and further being fused to each other in at least one portion thereof, wherein said foam is characterized by a density below 15 kg/m 3 , and wherein said density is characterized as being a uniform density, said uniform density being characterized as having at least 90% of said foam with densities that vary within a range of less than 15%, said microspheres are limited to size variation of less than 15%, said microspheres are coated with multiwall carbon nanotubes at said carbon nanotubes density of 1.5 gr/cc to 2.5 gr/cc.

2. The composition of matter of claim 1 , wherein said polymeric microspheres are selected from the group consisting of: polyvinylchloride, polyacrylonitrile, polyvinylidene chloride, polyimide, and any combination and/or derivative, and/or copolymer thereof.

3. The composition-of-matter of claim 1 , wherein at least 85% of said microspheres are further limited to length or diameter variation of 160 to 240 micrometers.

4. The composition-of-matter of claim 1 , further comprising reinforcing fiber filaments, said reinforcing fiber filaments being aramid fiber filaments.

5. The composition-of-matter of claim 1 , wherein said polymeric microspheres further comprise a conductive additive, said conductive additive comprising a material selected from the group consisting of: carbon, a conductive polymer, conductive metal particle, a magnetic metal particle, metal alloys, ceramics, a composite material and any mixture thereof, and wherein said material is characterized as having a size of at least one dimension thereof that ranges from about 1 nm to 1000 nm.

6. The composition-of-matter of claim 5 , wherein said carbon is in the form selected from the group consisting of: pristine carbon nanotubes, functionalized carbon nanotubes, single walled carbon nanotubes, graphene, fullerene, carbon black, graphite, a carbon fiber, and any combination thereof.

7. A sandwich panel comprising:
(a) a first skin and a second skin; and
(b) the composition of matter of claim 1
wherein said composition of matter is a core being located between a first skin and a second skin.

8. The sandwich panel of claim 7 , said first skin and said second skin are stitched to a core using yarn beams wherein said yarn is selected from the group consisting of: carbon, glass, aramid, PBI, PABI, PBO, polyimide, polyamide, Poly(ethylene terephthalate) (PET), and any combination thereof.

9. The sandwich panel of claim 7 , further comprising second foam wherein said second foam:
(a) comprises polymeric microspheres, said polymeric microspheres further being expanded and further being fused to each other in at least one portion thereof,
(b) is characterized by a density below 15 kg/m 3 , wherein said density is characterized as being a uniform density, said uniform density being characterized as having at least 90% of said foam with densities that vary within a range of less than 15%, and wherein
(c) said second foam filling a space surrounding said yarn beams.

10. The sandwich panel of claim 9 , wherein said second foam is characterized as having a density of at least 30% higher than the density of the foam being located between said first and second skin.

11. The sandwich panel of claim 7 , wherein said first skin, said second skin, or both further comprise a fibrous material and/or a resin.

12. The sandwich panel of claim 11 , wherein said resin is selected from the group consisting of: phenolic, epoxy, polyetheretherketone (PEEK), polyimides, polyamides, bismaleimides, polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polysulphone (PSU) and Polybutylene terephthalate (PBT).

13. The sandwich panel of claim 11 , wherein said fibrous material is selected from the group consisting of: carbon, glass, aramid, polybenzimidazole (PBI), polyimide, polyamide, PET, and any combination thereof.

14. The sandwich panel of claim 7 , wherein said first skin and/or said second skin are coated with a material selected from the group consisting of: a metal, a composite, a ceramic, a polymer, and any combination thereof.

15. The sandwich panel of claim 7 , wherein said foam is selected from the group consisting of: PVC foam, polyurethane (PU) foam, styrene acrylonitrile (SAN) foam, polyethylene, polyimide foam, phenolic foam, and polymethacrylimide (Rohacell) foam.

Assignees

• Technion Res & Dev Foundation
• Technion Res & Development Foundation

Inventors

• Vaikhanski Lev
• Cohen Yachin

Classifications

• B32B7/09

  by stitching, needling or sewing (by {mechanically connecting} fibrous layers {to another layer} B32B5/06) · CPC title

• C08J2203/22

  Expandable microspheres, e.g. Expancel® · CPC title

• C08J9/32 Primary

  from compositions containing microballoons, e.g. syntactic foams · CPC title

• C08J9/24

  by surface fusion and bonding of particles to form voids, e.g. sintering (of expandable particles C08J9/232) · CPC title

• B29K2995/0063

  Density · CPC title