Patents by Inventor Francis U. Hill
Francis U. Hill has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5192810Abstract: A method of forming complex polyimide foam shapes by impregnating a low density, open cell, reticulated foam with polyimide foam precursor, placing the combination in a mold, closing the mold, then heating the assembly to the foaming and curing temperatures of the precursor. As the powdered precursor expands, it spreads throughout the reticulated foam producing a product having substantially uniform density and polyimide foam characteristics. If desired, the reticulated foam can be removed from the product by using a material that outgasses and boils away at polyimide processing temperatures. Radar absorbing materials may be incorporated in the reticulated foam so that the final product will have uniformly distributed radar absorbing components with the desirable high temperature resistance and other properties of polyimide foams.Type: GrantFiled: December 16, 1991Date of Patent: March 9, 1993Assignee: Sorrento Engineering CorporationInventor: Francis U. Hill
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Patent number: 5188879Abstract: A method of manufacturing polyimide foam filled structures such as honeycomb panels. A polyimide foam precursor is prepared in powder form. A layer of the powder is heated and foamed at the resin condensation temperature and pre-cured to an easily handleable, stiff and inflexible state. A multi-cell, thin-walled structure having open cells along a surface is pressed into and through the foam sheet so that foam pieces fill the cells. The foam is then heated to a final cure temperature at which the foam becomes stable, resilient and flexible. Face sheets may be bonded to the structure to retain the foam pieces in the cells. If desired, the walls of the structure that contact the foam may be coated with an adhesive, such as a liquid polyimide adhesive resin precursor, so that the foam will be bonded to the cell walls when the liquid resin precursor is cured as a necessary result of the final foam cure conditions.Type: GrantFiled: July 15, 1991Date of Patent: February 23, 1993Assignee: Sorrento Engineering CorporationInventors: Francis U. Hill, Paul F. Schoenzart, Werner P. Frank
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Patent number: 5135959Abstract: A method of forming complex polyimide foam shapes by impregnating a low density, open cell, reticulated form with polymide foam precursor, placing the combination in a mold, closing the mold, then heating the assembly to the foaming and curing temperatures of the precursor. As the powdered precursor expands, it spreads throughout the reticulated foam producing a product having substantially uniform density and polyimide foam characteristics. If desired, the reticulated foam can be removed from the product by using a material that outgasses and boils away at polyimide processing temperatures. Radar absorbing materials may be incorporated in the reticulated foam so that the final product will have uniformly distributed radar absorbing components with the desirable high temperature resistance and other properties of polyimide foams.Type: GrantFiled: May 20, 1991Date of Patent: August 4, 1992Assignee: Sorrento Engineering CorporationInventor: Francis U. Hill
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Patent number: 5047436Abstract: A method of improving the flame resistance of foams, such as open cell polyimide foams, through the introduction of finely divided non-metallic inorganic particles which are gel forming and insoluble in water and polar organic liquids into the foam cells. A stable liquid suspension or gel, preferably aqueous is prepared using these particles. An opacifier such as finely divided titanium dioxide or tin oxide may also be added. An open cell foam product is placed in the gel until the cells fill with the gel. Excess gel is removed and the foam is dried, leaving the particles trapped in the cells. If desired, the foam may be post treated, such as by compression at the stabilizing temperature, resulting in a densified foam which further mechanically traps the particles and further improves the flame resistance.Type: GrantFiled: February 12, 1990Date of Patent: September 10, 1991Assignee: Sorrento Engineering CorporationInventors: Francis U. Hill, Lola E. Crosswhite
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Patent number: 5011558Abstract: A method of improving the flame resistance of foams, such as open cell polyimide foams, through the introduction of finely divided non-metallic inorganic particles which are gel forming and insoluble in water and polar organic liquids into the foam cells. A stable liquid suspension or gel, preferably aqueous is prepared using these particles. An opacifier such as finely divided titanium dioxide or tin oxide may also be added. An open cell foam product is placed in the gel until the cells fill with the gel. Excess gel is removed and the foam is dried, leaving the particles trapped in the cells. If desired, the foam may be post treated, such as by compression at the stabilizing temperature, resulting in a densified foam which further mechanically traps the particles and further improves the flame resistance.Type: GrantFiled: February 21, 1990Date of Patent: April 30, 1991Assignee: Sorrento Engineering CorporationInventors: Francis U. Hill, Lola E. Crosswhite
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Patent number: 5000813Abstract: A method of improving the flame resistance of foams, such as open cell polyimide foams, through the introduction of finely divided metal oxide particles into the foam cells. A stable water suspension or gel is prepared using particles of metal oxides, such as aluminum oxide and silicon dioxide. An opacifier such as titanium dioxide may also be added. An open cell foam product is placed in the gel until the cells fill with the gel. Excess gel is removed and the foam is dried, leaving the metal oxide particles trapped in the cells. If desired, the foam may be post treated, such as by compression at the stabilizing temperature, resulting in a densified foam which further mechanically traps the particles.Type: GrantFiled: February 12, 1990Date of Patent: March 19, 1991Assignee: Sorrento Engineering, Inc.Inventor: Francis U. Hill
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Patent number: 4988739Abstract: A method of improving the flame resistance of foams, such as open cell polyimide foams, through the introduction of finely divided metal oxide particles into the foam cells. A stable water suspension or gel is prepared using particles of metal oxides, such as aluminum oxide and silicon dioxide. An opacifier such as titanium dioxide may also be added. An open cell foam product is placed in the gel until the cells fill with the gel. Excess gel is removed and the foam is dried, leaving the metal oxide particles trapped in the cells. If desired, the foam may be post treated, such as by compression at the stabilizing temperature, resulting in a densified foam which further mechanically traps the particles.Type: GrantFiled: February 12, 1990Date of Patent: January 29, 1991Assignee: Sorrento Engineering, Inc.Inventor: Francis U. Hill
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Patent number: 4980389Abstract: A method of making polyetherimide foam precursors and flexible polyetherimide foams having improved specific tensile strength, resistance to high temperatures and flame, low density and flexibility at both high and cryogenic temperatures. 4,4'-oxydiphthalic anhydride (ODPA) is reacted with an alcohol to produce a diester, which is then reacted with a suitable monomeric polyamine such as meta phenylene diamine to produce a precursor. This material is dried to a solid block or powder. Upon heating, foaming occurs, resulting in a fine celled white friable mass. The foam is cured by heating for a suitable period and is ready for use.Type: GrantFiled: April 3, 1990Date of Patent: December 25, 1990Assignee: Irbit Research & Consulting AGInventors: Francis U. Hill, Paul F. Schoenzart, Werner P. Frank
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Patent number: 4980102Abstract: A method of manufacturing lightweight shapes from polyimide foam in which density discontinuities such as cavities, varying cell size, or swirl marks are substantially eliminated. A block or bun of polyimide foam is prepared in a conventional manner which results in a high density rind and other discontinuities. The foam is chopped into fine flakes in a chopper with a continuous flow of air to prevent electrostatic attachment of the flakes to the chopper and ducting. The flakes are mixed with a quantity of polyimide precursor and then heated to cause the precursor to bond the flakes into a uniform mass having highly uniform and predictable density. This is a very economical process since portions of the original bun may be used which would ordinarily be discarded. An alternative method is described whereby the flakes can be bonded together by using the precursor in the form of a partially cured foam either as a binder, or by making the flakes of partially cured foam.Type: GrantFiled: February 7, 1990Date of Patent: December 25, 1990Assignee: Sorrento Engineering, Inc.Inventor: Francis U. Hill
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Patent number: 4980004Abstract: A method of manufacturing lightweight shapes from polyimide foam in which density discontinuities such as cavities, varying cell size, or swirl marks are substantially eliminated. A block or bun of polyimide foam is prepared in a conventional manner which results in a high density rind and other discontinuities. The foam is chopped into fine flakes in a chopper with a continuous flow of air to prevent electrostatic attachment of the flakes to the chopper and ducting. The flakes are mixed with a quantity of polyimide precursor and then heated to cause the precursor to bond the flakes into a uniform mass having highly uniform and predictable density. This is a very economical process since portions of the original bun may be used which would ordinarily be discarded. An alternative method is described whereby the flakes can be bonded together by using the precursor in the form of a partially cured foam either as a binder, or by making the flakes of partially cured foam.Type: GrantFiled: February 7, 1990Date of Patent: December 25, 1990Assignee: Sorrento Engineering, Inc.Inventor: Francis U. Hill
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Patent number: 4978690Abstract: A method of making thermal insulating products comprising porous, lightweight, high temperature resistant inorganic particles in a polyimide foam matrix and the product thereof. A polyimide precursor powdered is mixed with about equal weight of flake-like porous inorganic particles to substantially uniformly coat the particles with powder. The mixture is placed in a mold and compressed slightly. The assembly is heated to the foaming temperature of the polyimide precursor for a period suitable to produce uniform foaming. Then the temperature is raised to the curing and crosslinking temperature of the precursor for a time period sufficient to produce complete cure. A high temperature and flame resistant, light weight, highly insulating product results. If desired, protective sheets of material may be bonded to selected product surfaces during or after the molding operation.Type: GrantFiled: July 12, 1989Date of Patent: December 18, 1990Assignee: Sorrento Engineering, Inc.Inventor: Francis U. Hill
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Patent number: 4962132Abstract: A method of improving the flame resistance of foams, such as open cell polyimide foams, through the introduction of finely divided non-metallic inorganic particles which are gel forming and insoluble in water and polar organic liquids into the foam cells. A stable liquid suspension or gel, preferably aqueous is prepared using these particles. An opacifier such as finely divided titanium dioxide or tin oxide may also be added. An open cell foam product is placed in the gel until the cells fill with the gel. Excess gel is removed and the foam is dried, leaving the particles trapped in the cells. If desired, the foam may be post treated, such as by compression at the stabilizing temperature, resulting in a densified foam which further mechanically traps the particles and further improves the flame resistance.Type: GrantFiled: December 11, 1989Date of Patent: October 9, 1990Assignee: Sorrento Engineering CorporationInventors: Francis U. Hill, Lola E. Crosswhite
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Patent number: 4935452Abstract: A method of improving the flame resistance of foams, such as open cell polyimide foams, through the introduction of finely divided metal oxide particles into the foam cells. A stable water suspension or gel is prepared using particles of metal oxides, such as aluminum oxide and silicon dioxide. An opacifier such as titanium dioxide may also be added. An open cell foam product is placed in the gel until the cells fill with the gel. Excess gel is removed and the foam is dried, leaving the metal oxide particles trapped in the cells. If desired, the foam may be post treated, such as by compression at the stabilizing temperature, resulting in a densified foam which further mechanically traps the particles.Type: GrantFiled: June 30, 1989Date of Patent: June 19, 1990Assignee: Sorrento Engineering, Inc.Inventor: Francis U. Hill
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Patent number: 4923907Abstract: A method of making thermal insulating products comprising porous, lightweight, high temperature resistant inorganic particles in a polyimide foam matrix and the product thereof. A polyimide precursor powdered is mixed with about equal weight of flake-like porous inorganic particles to substantially uniformly coat the particles with powder. The mixture is placed in a mold and compressed slightly. The assembly is heated to the foaming temperature of the polyimide precursor for a period suitable to product uniform foaming. Then the temperature is raised to the curing and crosslinking temperature of the precursor for a time period sufficient to product complete cure. A high temperature and flame resistant, light weight, highly insulating product results. If desired, protective sheets of material may be bonded to selected product surfaces during or after the molding operation.Type: GrantFiled: July 24, 1989Date of Patent: May 8, 1990Assignee: Sorrento Engineering, Inc.Inventor: Francis U. Hill
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Patent number: 4923651Abstract: A method of manufacturing lightweight shapes from polyimide foam in which density discontinuities such as cavities, varying cell size, or swirl marks are substantially eliminated. A block or bun of polyimide foam is prepared in a conventional manner which results in a high density rind and other discontinuities. The foam is chopped into fine flakes in a chopper with a continuous flow of air to prevent electrostatic attachment of the flakes to the chopper and ducting. The flakes are mixed with a quantity of polyimide precursor and then heated to cause the precursor to bond the flakes into a uniform mass having highly uniform and predictable density. This is a very economical process since portions of the original bun may be used which would ordinarily be discarded. An alternative method is described whereby the flakes can be bonded together by using the precursor in the form of a partially cured foam either as a binder, or by making the flakes of partially cured foam.Type: GrantFiled: June 30, 1989Date of Patent: May 8, 1990Assignee: Sorrento Engineering, Inc.Inventor: Francis U. Hill
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Patent number: 4865784Abstract: A method of making thermal insulating products comprising porous, lightweight, high temperature resistant inorganic particles in a polyimide foam matrix and the product thereof. A polyimide precursor provided is mixed with about equal weight of flake-like porous inorganic particles to substantially uniformly coat the particles with powder. The mixture is placed in a mold and compressed slightly. The assembly is heated to the foaming temperature of the polyimide precursor for a period suitable to produce uniform foaming. Then the temperature is raised to the curing and crosslinking temperature of the precursor for a time period sufficient to produce complete cure. A high temperature and flame resistant, light weight, highly insulating product results. If desired, protective sheets of material may be bonded to selected product surfaces during or after the molding operation.Type: GrantFiled: February 21, 1989Date of Patent: September 12, 1989Inventor: Francis U. Hill