Composite thermoplastic sheets including natural fibers

• US 7,431,980 B2
• Filed: 11/08/2004
• Issued: 10/07/2008
• Est. Priority Date: 11/08/2004
• Status: Active Grant

• Current Assignee: Hanwa Azdel, Inc.
• Original Assignee: AZDEL Incorporated (Hanwha Corporation)
• Inventors: Raghavendran, Venkat Krishna, Woodman, Daniel Scott, McHugh, John Joseph
• Primary Examiner(s): EDWARDS, NEWTON O
• Application Number:
  US10/983,535
• Publication Number:
  US 20060099393A1
• Time in Patent Office: 1,429 Days
• Field of Search: 428/303, 428/297.4, 428/300.7, 428/317.9, 156/245, 442/30, 442/35, 442/56, 442/57, 442/413, 442/416, 264/41, 264/322
• US Class Current: 428/297.4
• CPC Class Codes: B29C 70/30 Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
• CPC Class Codes: B32B 2262/065 Lignocellulosic fibres, e.g. jute, sisal, hemp, flax, bamboo
• CPC Class Codes: B32B 2262/10 Inorganic fibres layered products comprising a layer of natural mineral fibres B32B19/00
• CPC Class Codes: B32B 2266/0292 Thermoplastic elastomer
• CPC Class Codes: B32B 2266/06 Open cell foam
• CPC Class Codes: B32B 2307/716 Degradable
• CPC Class Codes: B32B 2307/718 Weight, e.g. weight per square meter
• CPC Class Codes: B32B 2419/00 Buildings or parts thereof walls, panels B32B2607/00
• CPC Class Codes: B32B 2605/003 Interior finishings
• CPC Class Codes: B32B 5/18 characterised by features of a layer of foamed material
• CPC Class Codes: B32B 5/32 at least two layers being foamed and next to each other
• CPC Class Codes: B32B 9/02 comprising animal or vegetable substances , e.g. cork, bamboo, starch
• CPC Class Codes: D04H 1/425 Cellulose series
• CPC Class Codes: D04H 1/4266 Natural fibres not provided for in group D04H1/425
• CPC Class Codes: D04H 1/60 the bonding agent being applied in dry state, e.g. thermo-activatable agents in solid or molten state, and heat being applied subsequently
• CPC Class Codes: D21H 11/12 Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse
• CPC Class Codes: D21H 13/26 Polyamides; Polyimides
• CPC Class Codes: D21H 17/34 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: Y10T 428/249924 Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix
• CPC Class Codes: Y10T 428/24995 : Two or more layers
• CPC Class Codes: Y10T 428/249986 : Void-containing component contains also a solid fiber or solid particle

Abstract

A composite sheet material includes, in an exemplary embodiment a porous core that includes at least one thermoplastic material and from about 20 weight percent to about 80 weight percent of natural fibers based on a total weight of the porous core. The natural fibers include at least one of kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, and coir fibers.

Claims

1. A thermoplastic composite sheet material comprising:

a permeable core comprising a thermoplastic resin material reinforced with a web of reinforcing fibers, and discontinuous natural fibers, said permeable core having a density from about 0.1 gm/cc to about 1.8 gm/cc, said permeable core including a surface region, said composite sheet moldable into predetermined shapes;

said natural fibers selected from the group consisting of kenaf fibers, jute fibers, flax fibers, hemp fibers, sisal fibers, coir fibers, and mixtures thereof.

2. A composite sheet material in accordance with claim 1 wherein said permeable core has an open cell structure with a void content of about 1 percent to about 95 percent of the total volume of said permeable core.

3. A composite sheet material in accordance with claim 1 wherein said permeable core comprises a thermoplastic resin selected from the group consisting of polyolefins, polystyrene, acrylonitryistyrene, butadiene, polyesters, polybutyleneterachlorate, polyvinyl chloride, polyphenylene ether, polycarbonates, polyestercarbonates, acrylonitrile-butylacrylate-styrene polymers, amorphous nylon, and mixtures thereof

4. A composite sheet material in accordance with claim 1 wherein said core comprises from about 20 to about 80 percent by weight of said natural fibers and reinforcing fibers, and from about 20 to about 80 percent by weight of said thermoplastic resin.

5. A composite sheet material in accordance with claim 1 wherein said core comprises from about 35 to about 55 percent by weight of said natural fibers and reinforcing fibers, and from about 45 to about 65 percent by weight of said thermoplastic resin.

6. A composite sheet material in accordance with claim 1 further comprising an adherent layer adjacent to said surface region.

7. A composite sheet material according to claim 6 wherein said adherent adjacent layer comprises at least one of a thermoplastic film, an elastomeric film, a metal foil, a thermosetting coating, an inorganic coating, a fiber based scrim, a non-woven fabric, and a woven fabric.

8. A composite sheet material in accordance with claim 1 wherein said said reinforcing fibers comprise at least one of metal fibers, metalized inorganic fibers, metalized synthetic fibers, glass fibers, graphite fibers, carbon fibers, ceramic fibers, basalt fibers, inorganic fibers, and aramid fibers.

9. A composite sheet material comprising:

a porous core comprising at least one themoplastic material reinforced with a web of reinforcing fibers and discontinuous natural fibers, comprising from about 20 weight percent to about 80 weight percent of reinforcing fibers and natural fibers based on a total weight of said porous core layer, said permeable core having a density from about 0.1gm/cc to about 1.8 gm/cc, said natural fibers selected from the group consisting of kenaf fibers, jute fibers, flax fibers, hemp fibers, sisal fibers, coir fibers, and mixtures thereof, said composite sheet moldable into predetermined shapes.

10. A composite sheet material in accordance with claim 9 wherein said porous core has an open cell structure with a void content of about 1 percent to about 95 percent of the total volume of said porous core.

11. A composite sheet material in accordance with claim 9 wherein said porous core comprises a thermoplastic resin selected from the group consisting of polyolefins, polystyrene, acrylonitrylstyrene, butadiene, polyesters, polybutyleneterachlorate, polyvinyl chloride, polyphenylene ether, polycarbonates, polyestercarbonates, acrylonitrile-butylacrylate-styrene polymers, amorphous nylon, and mixtures thereof.

12. A composite sheet material in accordance with claim 9 wherein said porous core comprises from about 35 to about 55 percent by weight of said natural fibcrs and reinforcing fibers, and from about 45 to about 65 percent by weight of said thermoplastic resin.

13. A composite sheet material in accordance with claim 9 further comprising at least one skin, each said skin covering at least a portion of a surface of said porous core layer, said skin comprising at least one of a thermoplastic film, an elastomeric film, a metal foil, a thermosetting coating, an inorganic coating, a fiber based scrim, a non-woven fabric, and a woven fabric.

14. A composite sheet material in accordancc with claim 9 wherein said reinforcing fibers comprise at least one of metal fibers, metalized inorganic fibers, metalized synthetic fibers, glass fibers, graphite fibers, carbon fibers, ceramic fibers, basalt fibers, inorganic fibers, and aramid fibers.