US4504338A
Expired / Lapsed
US
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Methods of producing composite foamed thermoplastic resin articles
Assignee: HR SMITHE (TECHNICAL DEVELOPMENTS) Ltd
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Filing: 1981-08-18
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Granted: 1985-03-12
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Expires: 2001-08-18
Abstract
Abstract Aromatic polymer materials, such as polyethersulphone, polysulphone or polycarbonates in granular or porous forms with a solvent such as acetone or butanone. The resultant mixture is thereafter compressed and compounded to significantly increase its density producing a pre-form substantially free of large irregular voids. The preform is then capable of being formed in a foamed structure under heat.
Inventors
- 👤 Peter J. Ives
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:03
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/14; C08J9/142; B; B29; B29B; B29B11/00; B29B11/06; B29B11/10; B29B11/12; B32; B32B; B32B27/00; B32B27/28; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/64; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/31504; Y10T428/31533
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
89 words
A method of producing thermoplastic articles consisting essentially of the steps of mixing an aromatic thermoplastic polymer material in granular or powder form with sufficient amount of a solvent comprising a non-aqueous volatile organic solvent or partial solvent of said polymer to form a gel, subjecting the gel so formed to compression to produce a pre-form of substantially greater density than said gel and free of large irregular holes and thereafter heating the pre-form so produced at a temperature at which it foams to form the foamed thermoplastic article.
Claim 2
Independent Claim
89 words
A method of producing thermoplastic articles consisting essentially of the steps of mixing an aromatic thermoplastic polymer material in granular or powder form with sufficient amount of a solvent comprising a non-aqueous volatile organic solvent or partial solvent of said polymer to form a gel, subjecting the gel so formed to compression to produce a pre-form of substantially greater density than said gel and free of large irregular holes and thereafter heating the pre-form so produced at a temperature at which it foams to form the foamed thermoplastic article.
Claim 3
Dependent Claim
25 words
The method according to claim 1 in which a foaming or nucleating agent is added to the polymer material and solvent as they are mixed.
Claim 4
Dependent Claim
22 words
The method according to claim 1 of producing foamed polyethersulphone materials in which powdered polyethersulfphone material is mixed with acetone or butanone.
Claim 5
Dependent Claim
32 words
A method according to claim 1 in which the polymer material/solvent mix is repeatedly compressed in a compression moulding tool, the compressed material being folded between repeated operations of the moulding tool.
Claim 6
Dependent Claim
20 words
A method according to claim 1 in which the polymer material/solvent mix is compressed by passage through a two-roll mill.
Claim 7
Dependent Claim
57 words
A method according to claim 1 in which the polymer material/solvent mix is repeatedly compressed in a compression moulding tool, the compressed material being folded between repeated operations of the moulding tool, and in which layers of the mixed, compressed material are stacked in a compression moulding tool and the tool is operated to produce a pre-form.
Claim 8
Dependent Claim
45 words
The method according to claim 1 in which the polymer material/solvent mix is compressed by passage through a two-roll mill and in which layers of the mixed, compressed material are stacked in a compression moulding tool and the tool is operated to produce a pre-form.
Claim 9
Independent Claim
38 words
The method according to claims 1 to 3, in which the polymer material/solvent mix is compressed by passage through an extruder and die which is cooled to a temperature below the foaming temperature of the polymer material/solvent mix.
Claim 10
Independent Claim
95 words
The method according to any one claims 1 to 3, in which the polymer material/solvent mix is compressed by passage through an extruder and die which is cooled to a temperature below the foaming temperature of the polymer material/solvent mix, and in which the pre-form so formed is initially dried at a temperature below that at which the polymer material/solvent mix foams and is then passed between a pair of pinch rollers heated to a temperature at which the polymer material/solvent mix will foam, so as to form a continuous length of foamed thermoplastic material.
Claim 11
Dependent Claim
32 words
A method according to claim 1 in which a pre-form formed by compression of the thermoplastic material/solvent mix is placed in mould and heated so as to form a foamed thermoplastic article.
Claim 12
Dependent Claim
53 words
The method according to claim 1, in which a pre-form formed by compression of the thermoplastic material/solvent mix is foamed in intimate contact with an adhesive coated surface of a layer of material, which layer of material is after foaming bonded to the foamed polymer material so as to form a composite structure.
Claim 13
Dependent Claim
16 words
The method according to claim 11, in which the layer is a fibre-reinforced thermoplastic composite material.
Claim 14
Dependent Claim
20 words
The method according to claim 12, in which the layer, the adhesive and the pre-form are polyethersulphone, polysulphone or polycarbonate.
Claim 15
Dependent Claim
30 words
The method according to claim 13, in which the pre-form material and the layer are of polyethersulphone, and in which the adhesive is a blend of polyethersulphone and N Methyl-2-Pyrrolidone.
Claim 16
Dependent Claim
23 words
A method according to claim 14, in which the adhesive is a blend of polyethersulphone and N Methyl-2-Pyrrolidone diluted with Xylene or Toluene.
Claim 17
Dependent Claim
84 words
A method according to claim 1 in which the polymer material/solvent mix is repeatedly compressed in a compression moulding tool, the compressed material being folded between repeated operations of the moulding tool, in which layers of the mixed, compressed material are stacked in a compression moulding tool and the tool is operated to produce a pre-form, and in which the pre-form is foamed in intimate contact with an adhesive coated surface of a layer of fibre reinforced thermoplastics material to form a composite structure.
Claim 18
Dependent Claim
88 words
A method according to claim 1 in which the polymer material/solvent mix is compressed by passage through an extruder and die which is cooled to a temperature below the foaming temperature of the polymer material/solvent mix, in which layers of the mixed, compressed material are stacked in a compression moulding tool and the tool is operated to produce a pre-form, and in which the pre-form is foamed in intimate contact with an adhesive coated surface of a layer of fibre reinforced thermoplastics material to form a composite structure.
Claim 19
Dependent Claim
124 words
A method according to claim 1 in which the polymer material/solvent mix is compressed by passage through an extruder and die which is cooled to a temperature below the foaming temperature of the polymer material/solvent mix, in which the pre-form so formed is initially dried at a temperature below that at which the polymer material/solvent mix foams and is then passed between a pair of pinch rollers heated to a temperature at which the polymer material/solvent mix will foam, to which pinch rollers are also passed one or more layers of fibre reinforced thermoplastic material, the surfaces of which layers which contact the pre-form being coated with a layer of adhesive such that a continuous length of composite foamed thermoplastic-reinforced thermoplastic material is produced.
Claim 20
Dependent Claim
44 words
A method of producing a thermoplastic article according to claim 1 wherein the thermoplastic material is an aromatic polymeric material selected from the group consisting of polyethersulphone, polysulphone and polycarbonates, and the organic solvent is selected from the group consisting of acetone and butanone.
Claim 21
Dependent Claim
20 words
The method according to claim 19, including the step of adding a foaming agent to said gel prior to compression.
Claim 22
Dependent Claim
23 words
The method according to claim 20 including the step of drying said pre-form for a period not less than 48 hours before heating.
References Cited (Backward Citations)
GB429316A
Cited
US2714076A
Cited
GB1062684A
Cited
GB1504559A
Cited
US4179540A
Cited
GB1569763A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-11 | 1988-09-10 | 1989-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-11 | 1992-09-10 | 1993-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-11 | 1996-09-10 | 1997-03-12 | $7700.00 | Window Closed / Lapsed |