Method of making composite material

• US 20060118989A1
• Filed: 12/07/2004
• Published: 06/08/2006
• Est. Priority Date: 12/07/2004
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Shinbach, Madeline P., Widagdo, Soemantri, Nwabunma, Domasius, Bentz, Bridget A., Olsen, Lee E., Marshall, Harry J., Martin, Michael C.
• Application Number:
  US11/007,530
• Publication Number:
  US 20060118989A1
• Time in Patent Office: Days
• US Class Current: 264/102
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/288 in solid form, e.g. powder or granules
• CPC Class Codes: B29C 48/2886 of fibrous, filamentary or filling materials, e.g. thin fibrous reinforcements or fillers
• CPC Class Codes: B29C 48/297 at several locations, e.g. using several hoppers or using a separate additive feeding
• CPC Class Codes: B29C 48/395 using screws surrounded by a cooperating barrel, e.g. single screw extruders
• CPC Class Codes: B29K 2105/06 containing reinforcements, fillers or inserts
• CPC Class Codes: B29K 2105/12 of short lengths, e.g. chopped filaments, staple fibres or bristles
• CPC Class Codes: B29K 2105/16 Fillers

Abstract

A method of making a composite material wherein a molten polymeric material is added to frangible solid particulates within a screw extruder.

Claims

1. A method of making a composite material, the method comprising:

providing an extruder having a housing, a barrel defined by the housing, and at least one screw at least partially disposed within the barrel, a first inlet port that extends through the housing and opens to the barrel, a second inlet port that extends through the housing and opens to the barrel and is disposed downstream from the first inlet port, and an outlet port that opens to the barrel and is downstream from the second inlet port;

introducing a plurality of frangible solid particulates into the first inlet port such that the frangible solid paiticulates are engaged by the screw;

introducing a molten polymeric material into the extruder through the second inlet port such that the molten polymeric material engages the screw and combines with the frangible solid particulates to form a molten composite material comprising a dispersion of the frangible solid particulates in the molten polymeric material; and

obtaining the molten composite material from the outlet port.

2. A method according to claim 1, further comprising solidifying the molten composite material.

3. A method according to claim 2, wherein the included volume of trapped gas in the solidified composite material, exclusive of the frangible solid particulates, is less than 4 percent by volume, based on the total volume of the solidified composite material.

4. A method according to claim 2, wherein the solidified composite material contains less than or equal to 1.2 percent by volume of broken frangible solid particulates, based on the total volume of the solidified composite material.

5. A method according to claim 1, wherein the extruder further comprises a vent that extends through the housing and opens to the barrel.

6. A method according to claim 5, wherein the vent is located upstream from the first inlet port.

7. A method according to claim 5, wherein the vent is located between the first and second inlet ports.

8. A method according to claim 5, wherein the vent is located downstream from the second inlet port.

9. A method according to claim 5, wherein the extruder comprises at least two screws that are at least partially disposed in the barrel.

10. A method according to claim 5, wherein the vent has a pressure of less than 1.3 kilopascals.

11. A method according to claim 1, further comprising at least partially devolatilizing the molten polymeric material prior to introducing it into the second inlet port.

12. A method according to claim 1, further comprising heating the frangible solid particulates while the frangible solid particulates are disposed within the barrel and prior to combining them with the molten polymeric material.

13. A method according to claim 1, wherein the average size of the frangible solid particulates is in a range of from at least 10 up to and including 150 microns in diameter.

14. A method according to claim 1, wherein the frangible solid particulates comprise at least one of glass microbubbles, chopped glass fibers, or hollow ceramic microspheres.

15. A method according to claim 1, wherein the frangible solid particulates comprise glass microbubbles.

16. A method according to claim 1, wherein the frangible solid particulates have a multimodal size distribution.

17. A method according to claim 1, wherein the average density of the frangible solid particulates is in a range of from at least 0.1 grams per milliliter up to and including 3.0 grams per milliliter.

18. A method according to claim 1, wherein, on a total volume basis, the frangible solid particulates comprise from at least 40 percent up to and including 60 percent by volume, based on the total volume of the composite material.

19. A method according to claim 1, wherein the molten polymeric material comprises molten thermoplastic resin.

20. A method according to claim 19, wherein the molten thermoplastic resin is selected from the group consisting of polyolefins, ionomers, polyether blocked polyamide thermoplastic elastomers, polyimides, acrylonitrile-butadiene-styrene polymers, acetals, acrylics, cellulosics, chlorinated polymers, fluoropolymers, polyamides, polyesters, polycarbonates, and combinations thereof.