Moldable fibrous mat and method of making the same

• US 4,418,031 A
• Filed: 03/02/1982
• Issued: 11/29/1983
• Est. Priority Date: 04/06/1981
• Status: Expired due to Term

• Current Assignee: Van Dresser Corporation
• Original Assignee: Van Dresser Corporation
• Inventors: Doerer, Richard P., Karpik, Joseph T.
• Primary Examiner(s): Bell, James J.
• Application Number:
  US06/352,501
• Time in Patent Office: 637 Days
• Field of Search: 428/288, 428/296, 428/326, 264/122, 264/241, 264/257, 264/259
• US Class Current: 264/241
• CPC Class Codes: B27N 3/12 from fibres
• CPC Class Codes: B27N 5/00 Manufacture of non-flat articles
• CPC Class Codes: B29C 2045/0093 of articles provided with an attaching element
• CPC Class Codes: B29C 33/18 using vacuum
• CPC Class Codes: B29C 45/14786 Fibrous material or fibre containing material, e.g. fibre mats or fibre reinforced material
• CPC Class Codes: B29C 70/38 Automated lay-up, e.g. using robots, laying filaments according to predetermined patterns application heads for tyres B29D30/28
• CPC Class Codes: B29C 70/74 Moulding material on a relatively small portion of the preformed part, e.g. outsert moulding B29C70/845 takes precedence
• CPC Class Codes: B29C 70/86 Incorporated in coherent impregnated reinforcing layers, e.g. by winding
• CPC Class Codes: D04H 1/425 Cellulose series
• CPC Class Codes: D04H 1/54 by welding together the fibres, e.g. by partially melting or dissolving in combination with needling D04H1/485
• CPC Class Codes: D04H 1/558 in combination with mechanical or physical treatments other than embossing
• 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: Y10T 428/253 Cellulosic [e.g., wood, paper, cork, rayon, etc.]
• CPC Class Codes: Y10T 442/692 Containing at least two chemically different strand or fiber materials

Abstract

A moldable fibrous mat from which a product of predetermined shape can be molded by the application of heat and/or pressure. The mat consists essentially of base fibers and carrier fibers with the base fibers having a substantially higher softening temperature, if any, than the carrier fibers. The fibers intertwine to resist separation. The carrier fibers are bonded to the base fibers and to each other to form connections. There is also disclosed a method by which the moldable fibrous mat is made and product made from the mat, which product may be of uniform density or have areas of differing density.

Claims

1. A two-stage method of manufacturing a permanently rigid shaped end product comprising:

(1) in a first stage and by a dry process, making a soft, flexible, handleable fibrous mat by providing a mixture consisting essentially of cellulose base fibers, linking and activatable bonding means including carrier fibers, and a thermosetting ingredient,

forming said mixture into a mat in which said fibers are interspersed,

activating said bonding means to cause said carrier fibers to bond to said base fibers and to each other forming connections therebetween and holding said fibers together,

said thermosetting ingredient remaining in an uncured state during said activation of said bonding means and

(2) thereafter making said end product in a second stage at any later time by subjecting said mat to sufficient heat and pressure in a compression molding operation to cause said thermosetting ingredient to cure and to compress the material to the desired thickness and density, and molding and bonding an attachment to said end product simultaneously with the making of said end product and in said compression molding operation, thereby completing the manufacture of said end product.

2. A method as defined in claim 1, wherein said base fibers are wood.

3. A method as defined in claim 1, wherein said carrier fibers are thermoplastic in nature, and wherein said bonding is caused by heating the said thermoplastic carrier fibers to their tack point but not to melting, thus maintaining their essentially fibrous form, said tack point being below the curing temperature of the thermosetting ingredient involved, thereby avoiding any curing in stage 1.

4. A method as defined in claim 3, wherein said carrier fibers are formed of thermoplastic material selected from the group consisting of the vinyl family, the polyester family, the polyolefin family, the polyamide family and any physical or chemical combination of the above families.

5. A method as defined in claim 1, wherein said bonding means includes a chemical bonding agent which effects the aforesaid bonding of said base and carrier fibers.

6. A method as defined in claim 1, 2, 3, 4 or 5, wherein said attachment is made of a thermosetting material which is cured and bonded as aforesaid by the heat employed in the molding of said end product.

7. A method as defined in claim 6, wherein said thermosetting material is a polyester resin.

8. A method as defined in claim 6 wherein said thermosetting material is a phenolic resin.