# US 7,612,161 B2 · Method for treating extremely small particles of plastic

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- Number: US 7,612,161 B2
- Document ID: US7612161B2
- Status: Granted
- Kind: B2
- Application number: 11/409,796
- Filed: 2006-04-24
- Published: 2007-10-25
- Granted: 2009-11-03
- Earliest claimed: 2006-04-24
- Assignees: Phoenix Technologies International, LLC
- Inventors: Donald W. Hayward; Daniel L. Witham
- Web page: https://patentgrep.com/patent/US7612161B2

## CPC

- B29B 9/08: by agglomerating smaller particles
- B29B 9/06: in the form of filamentary material, e.g. combined with extrusion
- B29C 48/04: Particle-shaped (making granules B29B9/00)
- B29C 48/05: Filamentary, e.g. strands
- B29C 48/09: Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
- B29C 48/345: Extrusion nozzles comprising two or more adjacently arranged ports, for simultaneously extruding multiple strands, e.g. for pelletising
- B29C 2793/009: after shaping
- B29K 2025/00: Use of polymers of vinyl-aromatic compounds {or derivatives thereof} as moulding material
- B29K 2027/06: PVC, i.e. polyvinylchloride
- B29K 2033/12: {Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate}
- B29K 2033/20: PAN, i.e. polyacrylonitrile
- B29K 2067/00: Use of polyesters {or derivatives thereof}, as moulding material
- B29K 2069/00: Use of PC, i.e. polycarbonates {or derivatives thereof}, as moulding material
- B29K 2071/00: Use of polyethers {, e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof}, as moulding material
- B29K 2077/00: Use of {PA, i.e.} polyamides, e.g. polyesteramides {or derivatives thereof}, as moulding material
- B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS

## Abstract

A method for treating extremely small particles of plastic comprises providing a quantity of plastic particles having an average mean particle size ranging from about 0.0005 inch to about 0.05 inch in diameter, heating the plastic particles to a temperature sufficient to cause at least a portion of the plastic particles to adhere to one another, and forming the adhered plastic particles into pellets, said pellets having substantially the same average surface-to-volume ratio as the bulk, un-adhered plastic particles.

## Claims

### Claim 1

A process for treating extremely small particles of plastic, comprising:
providing a quantity of plastic particles having an average mean particle size ranging from about 0.0005 inch to about 0.05 inch in diameter;
heating the plastic particles to a temperature sufficient to cause at least a portion of the plastic particles to adhere to one another; and
forming the adhered plastic particles into pellets, said pellets having substantially the same average surface-to-volume ratio as the bulk, un-adhered plastic particles.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the plastic comprises polyolefin, polystyrene, polyacrylate, polymethacrylate, polyvinyl chloride, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyester, polycarbonate, polyether, polyamide, or a derivative, blend, or copolymer thereof.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the average mean particle size of the plastic particles is about 0.01 inch in diameter.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the heating is accomplished by electrical resistance heating, flame heating, infrared radiant heating, or hot gas heating.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the heating is accomplished by frictional engagement between the particles.

### Claim 6 (depends on 1)

The process according to claim 1, wherein at least some of the plastic particles are heated to a temperature greater than or equal to their glass transition temperature.

### Claim 7 (depends on 1)

The process according to claim 1, wherein the plastic particles are heated to a temperature greater than about 125 degrees Celsius.

### Claim 8 (depends on 1)

The process according to claim 1, wherein the pellets are formed into cylinders, flakes, spheres, cubes, or misshapen chunks.

### Claim 9 (depends on 1)

The process according to claim 1, wherein the pellets are formed by passing the heated plastic particles through die passageways.

### Claim 10

A process for treating extremely small particles of plastic, comprising:
providing a quantity of plastic particles having an average mean particle size about 0.01 inch in diameter;
heating the plastic particles, by frictional engagement, electrical resistance heating, flame heating, infrared radiant heating, or hot gas heating, to a temperature greater than or equal to their glass transition temperature, to cause at least a portion of the plastic particles to adhere to one another; and
forming the adhered plastic particles into pellets in the form of cylinders, flakes, spheres, cubes, or misshapen chunks, by passing the heated plastic particles through die passageways, said pellets having substantially the same average surface-to-volume ratio as the bulk, un-adhered plastic particles.

### Claim 11 (depends on 10)

The process according to claim 10, wherein the plastic comprises polyolefin, polystyrene, polyacrylate, polymethacrylate, polyvinyl chloride, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyester, polycarbonate, polyether, polyamide, or a derivative, blend, or copolymer thereof.

### Claim 12 (depends on 10)

The process according to claim 10, wherein the plastic particles are heated to a temperature greater than about 125 degrees Celsius.

### Claim 13

A process for treating extremely small particles of plastic, comprising:
providing a quantity of plastic particles, comprising polyolefin, polystyrene, polyacrylate, polymethacrylate, polyvinyl chloride, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyester, polycarbonate, polyether, polyamide, or a derivative, blend, or copolymer thereof, having an average mean particle size about 0.01 inch in diameter;
heating the plastic particles, by frictional engagement, electrical resistance heating, flame heating, infrared radiant heating, or hot gas heating, to a temperature greater than about 125 degrees Celsius, to cause at least a portion of the plastic particles to adhere to one another; and
forming the plastic particles into pellets in the form of cylinders, flakes, spheres, cubes, or misshapen chunks, by passing the plastic particles through die passageways, said pellets having substantially the same average surface-to-volume ratio as the bulk, un-adhered plastic particles.