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US4407982A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for the manufacture of foamed structures

Assignee: DuPont Canada Inc
•
Filing: 1982-02-03
•
Granted: 1983-10-04
•
Expires: 2002-02-03
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Abstract

Abstract An improvement in a process for the production of polyurethane foam is disclosed, in which a first component is admixed and reacted with a second component and in which the first component has a viscosity at least two times the viscosity of the second component, thereby resulting in a nonuniform distribution of the cells of the foam. The improvement comprises admixing the second component with 1-5%, by weight, of the second component, of fumed silica prior to admixing the first and second components. The amount of fumed silica is controlled so that the polyurethane foam subsequently obtained has a substantially uniform distribution of cells. A process for the production of a foamed thermoplastic structure is also disclosed in which at least part of the normally liquid chlorofluorocarbon blowing agent is added as a composition comprising an admixture of 5-99%, by weight, of fumed silica and 1-95%, by weight, of a normally liquid chlorofluorocarbon adsorbed thereon. The composition is in the form of a dry free-flowing powder.

Inventors

  • 👤 John M. Elgie

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 23:27
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/0066; C08J2375/00; C08J2375/04

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 135 words
In a process for the production of polyurethane foam in which a first component is admixed and reacted, in the presence of a normally liquid blowing agent, with a second component said first component being an isocyanate, and said second component being a polyol and in which the first component has a viscosity at least two times the viscosity of the second component, the difference in the viscosities being such that but for the improvement hereinafter set forth the resultant polyurethane foam would have nonuniform distribution of cells, the improvement comprising admixing the second component with 1-5%, by weight, of the second component, of fumed silica prior to admixing said first and second components, the amount of silica so admixed being such that the polyurethane foam subsequently obtained has a substantially uniform distribution of cells.
Claim 2
Dependent Claim 135 words
In a process for the production of polyurethane foam in which a first component is admixed and reacted, in the presence of a normally liquid blowing agent, with a second component said first component being an isocyanate, and said second component being a polyol and in which the first component has a viscosity at least two times the viscosity of the second component, the difference in the viscosities being such that but for the improvement hereinafter set forth the resultant polyurethane foam would have nonuniform distribution of cells, the improvement comprising admixing the second component with 1-5%, by weight, of the second component, of fumed silica prior to admixing said first and second components, the amount of silica so admixed being such that the polyurethane foam subsequently obtained has a substantially uniform distribution of cells.
Claim 3
Dependent Claim 23 words
The process of claim 1 in which fumed silica and normally liquid chlorofluorocarbon blowing agent are added, in combination, to the second component.
Claim 4
Dependent Claim 30 words
The process of claim 1 or claim 2 in which the normally liquid chlorofluorocarbon is selected from the group consisting of trichloromonofluoromethane, dichlorodifluoromethane, monochlorodifluoromethane, trichlorotrifluoroethane and dichlorotetrafluoroethane, and mixtures thereof.
Claim 5
Dependent Claim 20 words
The process of claim 2 in which the chlorofluorocarbon is one component of a mixture with another liquid blowing agent.

References Cited (Backward Citations)

US3072582A Cited
US4048208A Cited
US4101467A Cited
US4217422A Cited
US4278770A Cited
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US4275172A Cited
US4317888A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1986-10-03 1987-04-04 1987-10-04 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1990-10-03 1991-04-04 1991-10-04 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1994-10-03 1995-04-04 1995-10-04 $7700.00 Window Closed / Lapsed

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