Manufacture of flat surfaced composites comprising powdered fillers in a polymer matrix

• US 6,787,246 B2
• Filed: 10/05/2001
• Issued: 09/07/2004
• Est. Priority Date: 10/05/2001
• Status: Expired due to Fees

• Current Assignee: The 323 Trust
• Original Assignee: Kreido Laboratories (Namliong SkyCosmos, Inc.)
• Inventors: Lichtenberger, Philip L., Holl, Richard A., Yao, Kenneth S.
• Primary Examiner(s): Kelly, Cynthia H.
• Assistant Examiner(s): FERGUSON, LAWRENCE D
• Application Number:
  US09/973,290
• Publication Number:
  US 20040151892A1
• Time in Patent Office: 1,068 Days
• Field of Search: 428/548, 428/212, 428/213, 419/10
• US Class Current: 428/548
• CPC Class Codes: B29C 43/02 of articles of definite length, i.e. discrete articles B29C35/0227 takes precedence
• CPC Class Codes: B29C 43/146 for making multilayered articles
• CPC Class Codes: B29C 70/58 comprising fillers only , e.g. particles, powder, beads, flakes, spheres B29C70/025 takes precedence, agglomerating hollow spheres to produce synthetic foam B29C70/66; compounding ingredients per se C08K
• CPC Class Codes: B29K 2503/04 Inorganic materials
• CPC Class Codes: B29L 2031/772 Articles characterised by their shape and not otherwise provided for closed loop B29L2031/709; ring-like B29L2031/7096; corrugated B29L2016/00, flat B29L2007/00; hollow B29L2022/00; screw-threaded B29L2001/00; toothed B29L2031/775; corrugated tubes B29L2023/18
• CPC Class Codes: B32B 15/16 next to a particulate layer
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2264/10 Inorganic particles
• CPC Class Codes: B32B 2457/00 Electrical equipment
• CPC Class Codes: B32B 5/30 one layer being formed of particles, e.g. chips, granules, powder
• CPC Class Codes: Y10T 428/12028 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Abstract

Composite materials, particularly those that are highly filled, e.g. comprising about 60 to 70 volume % of finely powdered filler material in a polymer matrix, are made by dissolving the polymer in a volatilisable solvent and forming a homogeneous mixture of the components by high shear mixing. The solvent is then removed while maintaining complete homogeneity in the mixture by evaporating much of the solvent in a high shear mill, then extruding an extremely thin film or tape (e.g. 0.0125 mm (0.0005 in)) from which the remaining solvent is removed by heating without introducing any appreciable non-uniformity, such as bubble holes. Required bodies are formed from the dried film or tape by stacking the thin coherent layers, typically about 6 to 120, then heating and pressing the stack in a mold melting the polymer, uniting the separate layers and dispersing the melted polymer into the interstices between the filler particles.

Claims

1. Articles consisting of bodies of composite materials comprising finely powdered filler material particles distributed in a polymer matrix;

wherein each body comprises a composite mixture of filler material particles and the balance polymer, the polymer being one which is soluble in a volatilizable solvent that has been volatilized from the mixture;

wherein each body comprises a stack of a plurality of united thin coherent layers in number sufficient to provide a unitary body of the desired thickness; and

wherein the body has been formed from the stack of thin coherent layers by subjecting the stack to a temperature

sufficient to melt the polymer and to a pressure sufficient to unite the thin coherent layers into a unitary body and disperse the melted polymer into the interstices between the filler material particles.

2. Articles as claimed in claim 1, wherein body of composite material has been formed from a stack of thin coherent layers of thickness from 0.0125 mm (0.0005 in) to 0.01 mm (0.004 (in).

3. Articles as claimed in claim 1, wherein the body of composite material has been formed from a stack of from 6 to 120 thin coherent layers.

4. Articles as claimed in claim 1, wherein the filler material particles selected from the group comprising particles of inorganic material, particles of electromagnetic material, particles of a core of inorganic material covered with a layer of a metal oxide material, particles of metal material, particles of magnetic material, and particles of low dielectric constant high melting point polymer material, all of which particles may be hollow.

5. Articles as claimed in claim 4, wherein the filler material particles are of size in range 0.1 to 50 micrometers, and consist of a mixture of filler material particles of different chemical compositions.

6. Articles as claimed in claim 1, and comprising a layer of conductive metal applied to a surface of the body by sputtering or by direct bonding of conductive metal foil under heat and pressure in a vacuum.

7. Articles as claimed in claim 1, and comprising substrates for electronic circuits formed from the heated and pressurized composite mixture.

8. Articles as claimed in claim 1, wherein the melted polymer is dispersed substantially uniformly into the interstices between the filler material particles.