Material for molding thermosetting resin sheet, production process, and molded product

• US 6,592,986 B1
• Filed: 11/24/2000
• Issued: 07/15/2003
• Est. Priority Date: 05/26/1998
• Status: Expired due to Fees

• Current Assignee: Japan Composite Co., Ltd. (Mitsui Chemicals)
• Original Assignee: Mitsui Takeda Chemicals Inc (Mitsui Chemicals)
• Inventors: Shibata, Takashi, Akiyama, Koichi, Miyashita, Hiromu, Hakotani, Masahiro
• Primary Examiner(s): Dawson, Robert
• Assistant Examiner(s): Keehan, Christopher M
• Application Number:
  US09/701,135
• Time in Patent Office: 963 Days
• Field of Search: 428/413, 428/295.1, 524/492, 524/297.4, 524/493, 524/301.4, 524/332, 524/859, 523/209, 523/216, 523/149
• US Class Current: 428/332
• CPC Class Codes: B29C 70/025 with particular filler
• CPC Class Codes: B29C 70/502 by first forming a mat composed of short fibres
• CPC Class Codes: B29C 70/882 partly or totally electrically conductive, e.g. for EMI shielding conductive floors or floor coverings H05F3/025; EMI shielding in general H05K9/00
• CPC Class Codes: C08K 7/04 inorganic
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: H05K 9/0088 comprising a plurality of shielding layers; combining different shielding material structure
• CPC Class Codes: H05K 9/009 comprising electro-conductive fibres, e.g. metal fibres, carbon fibres, metallised textile fibres, electro-conductive mesh, woven, non-woven mat, fleece, cross-linked
• CPC Class Codes: Y10T 428/249933 Fiber embedded in or on the surface of a natural or synthetic rubber matrix
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix
• CPC Class Codes: Y10T 428/249952 At least one thermosetting synthetic polymeric material layer
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/31511 Of epoxy ether

Abstract

The present invention presents an SMC with which the electrically conductive layer does not break down or become non-uniform during molding and with which molded articles with excellent electromagnetic wave shielding capability and electric conductivity can be produced. This SMC is a thermosetting resin sheet molding compound having at least one continuous layer of electrically conductive fibers with a fiber length of 50 μ to 5 mm, and it is further preferred that electrically conductive powder is uniformly dispersed throughout the entire molding compound. These SMCs can be produced by impregnating a reinforcing material with a thermosetting resin composition which is combined with the above-mentioned electrically conductive fibers, or the electrically conductive fibers and electrically conductive powder, and forming at least one continuous layer of these electrically conductive fibers adjacent to this reinforcement layer.

Claims

1. A thermosetting resin impregnated sheet molding compound comprising:

at least one reinforcement layer impregnated with a thermosetting resin and, disposed on at least one side of the reinforcement layer,

at least one continuous layer of electrically conductive fibers having a fiber length of 0.2 mm to 1 mm,

wherein an electrically conductive powder is uniformly dispersed throughout the reinforcement layer and the continuous layer of electrically conductive fibers.

2. The thermosetting resin impregnated sheet molding compound according to claim 1, wherein the continuous layer of electrically conductive fibers is formed by causing a thermosetting resin composition, which comprises the thermosetting resin, the electrically conductive fibers and the electrically conductive powder, to penetrate into the reinforcement layer.

5. A molded article, comprising one or more of the thermosetting resin impregnated sheet molding compounds according to claim 1.

6. A molded article, comprising one or more of the thermosetting resin impregnated sheet molding compounds according to claim 2.

7. A molded article, which is produced by curing one or more of the thermosetting resin impregnated sheet molding compounds according to claim 1 in a mold.

3. A method for producing a thermosetting resin impregnated sheet molding compound, comprising:

forming at least one continuous layer of electrically conductive fibers having a fiber length of 0.2 mm to 1 mm adjacent to at least one side of a reinforcement layer impregnated with a thermosetting resin, wherein the continuous layer of electrically conductive fibers and the reinforcement layer include an electrically conductive powder.

4. A method for producing a thermosetting resin impregnated sheet molding compound, comprising:

causing a thermosetting resin composition, which comprises a thermosetting resin, electrically conductive fibers having a fiber length of 0.2 mm to 1 mm and an electrically conductive powder, to penetrate into at least one side of a reinforcement layer.