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US 4,454,248 AGranted
Open cell rigid thermoset foams and method
AssigneeThe Boeing Company
InventorsMarlan R. Pollock, Marlyn F. Harp
Life of this patent
Estimating the term…
Abstract
A rigid porous, deformation resisting, nonresilient inflexible thermoset resin foam having macroscopic open cells and the method of making the same. The method comprises foaming and partially curing a polyepoxide or polyurethane resin in which the cells are closed. The partially cured resin is softened by heating and then crushed to compress the cells to produce an open-celled product. The crushed foam is reexpanded and finally cured. The foam may be filled for strengthening with a filler such as carbon black before or after the final cure.
Claims49
A method of producing a deformation resisting, non-resilient, inflexible, rigid, impregnable plastic thermosetting foam structure having open cells comprising:
- foaming and partially curing a foamable, curable resin mixture to a B-stage state of cure, the foam becoming rigid in the partial cure and having closed cells;
- softening the partially cured foam;
- compressing to crush the foam material to a thickness less than its original thickness in order to cause the walls forming the cells to rupture to produce an open-celled structure;
- reexpanding the compressed open cell foam material;
- and
- finally curing the open cell foam to be rigid and having inherent great structural strength.
3 more elements
A method of producing a deformation resisting, non-resilient, inflexible, rigid impregnable plastic thermosetting foam structure having open cells comprising,
- admixing a modified polyepoxide produced by reacting a polyepoxide having a ##STR5## equivalency greater than one with a curing and hardening agent therefor, said curing and hardening agent being present in a relatively small amount and less than the amount sufficient to harden and cure the polyepoxide, a curing and hardening agent for epoxies in an amount sufficient to harden and completely cure the modified polyepoxide, and a decomposable blowing agent in an amount sufficient to foam the modified polyepoxide;
- gelling the resultant mixture by maintaining the same at a temperature in the range of 45 degrees F. to 130 degrees F. for an interval in the range of 6 to 24 hours;
- force foaming and partially curing the gelled product by heating to a temperature in the range of 90 degrees F. to 150 degrees F. to an interval in the range of 2 to 6 hours to form a closed-cell foam;
- softening the foam by heating at a temperature in the range of 150 degrees F. to 250 degrees F.;
- compressing and crushing the softened foam to open the cells;
- and
- reexpanding the crushed open-celled foam by heating to a temperature in the range of 150 degrees F. to 250 degrees F.
4 more elements
A method of producing a deformation resisting, non-resilient, inflexible, rigid plastic thermosetting foam structure having open cells comprising:
- admixing a modified polyepoxide produced by reacting a polyepoxide having a ##STR6## equivalency in the range of 175 to 210 produced by reacting bisphenol A and epichlorohydrin, a polyamide curing and hardening agent for polyepoxides produced by condensing a polybasic carboxylic acid having from 1 to 26 carbon atoms in the molecule with a polyamine formed from a polymerizable amine having from 2 to 26 carbon atoms in the molecule in an amount from 0.2 to 2 parts by weight per 100 parts by weight of said polyepoxide;
- said reacting being carried on at a temperature in the range of 180 degrees F. to 220 degrees F. for a period of from 1/2 to 11/2 hours;
- ligroine in an amount in the range of 7 to 9 parts by weight;
- 4. 4' diamino diphenyl methane in an amount in the range of 23 to 27 parts by weight;
- a blowing agent mixture of a polyepoxide having a ##STR7## equivalency in the range of 175 to 210, and N,N' dimethyl N,N' dinitrosoterephthamide in an amount of 1 part by weight per 3 parts by weight of said polyepoxide, said blowing agent mixture being present in an amount in the range of 23 to 27 parts by weight;
- a plasticizer comprising a liquid mixture of polysulfide polymers produced by condensing an alkaline polysulfide with a dihalide in an amount in the range of 9 to 11 parts by weight;
- and
- triethylene tetramine in an amount in the range of 2 to 3 parts by weight, each per 100 parts by weight of modified polyepoxide;
- gelled the resulting mixture in a mold by maintaining the same at a temperature in the range of 50 degrees F. to 90 degrees F. for a period in the range of 8 to 16 hours;
- force foaming and partially curing the resultant gelled product by heating the same to a temperature in the range of 110 degrees F. to 130 degrees F. for an interval in the range of 3 to 5 hours;
- heating the mixture at a temperature in the range of 140 degrees F. to 160 degrees F. for an interval in the range of 3 to 5 hours;
- and
- subsequently heating the mixture to a temperature in the range of 190 degrees F. to 210 degrees F. for a period in the range of 50 to 70 minutes for each inch of thickness of the resulting closed-cell product;
- softening the product to a temperature in the range of 195 degrees F. to 205 degrees F.;
- compressing the closed-cell product to approximately one-half the original expanded thickness to cause the walls forming the closed cells to rupture to produce an open-celled product;
- reexpanding the open-celled foam material by heating to a temperature in the range of 210 degrees F. to 215 degrees F. and maintaining the temperature for an interval in the range of 10 to 30 minutes.
13 more elements
A rigid porous, deformation resisting, non-resilient inflexible, thermoset resin foam having macroscopic open cells formed by:
- admixing a B-stagable polymerizable thermosetting resin mixture selected from the group consisting of a curable polyepoxide resin, a polyurethane formed from a polyester resin and an isocynate compound, a polyurethane formed from a polyether resin and an isocynate compound, and mixtures thereof, and a forming agent for the resin mixture in an amount sufficient to foam the same;
- B-staging the resulting curable mixture by heating to a temperature in the range of 50 degrees F. to 180 degrees F. and maintaining the temperature for a time sufficient to foam the mixture and partially cure the same to produce a partially cured closed-cell foam material;
- softening the resulting partially cured foam material by heating until it can be indented with a finger;
- compressing and crushing the softened closed-cell foam to approximately one-half its original thickness to cause the walls forming the cells to rupture to produce an open-celled foam;
- reexpanding the opened-celled foam by heating until the structure is expanded.
2 more elements
A rigid porous, deformation resisting, non-resilient inflexible, thermoset resin foam having macroscopic open cells formed by,
- admixing a modified polyepoxide produced by reacting a polyepoxide having a ##STR8## equivalency greater than one with a curing and hardening agent therefor, said curing and hardening agent being present in a relatively small amount and less than the amount sufficient to harden and cure the polyepoxide, a curing and hardening agent for epoxies in an amount sufficient to harden and completely cure the modified polyepoxide, and a decomposable blowing agent in an amount sufficient to foam the modified polyepoxide;
- gelling the resultant mixture by maintaining the same at a temperature in the range of 45 degrees F. to 130 degrees F. for an interval in the range of 6 to 24 hours;
- force foaming and partially curing the gelled product by heating to a temperature in the range of 90 degrees F. to 150 degrees F. to an interval in the range of 2 to 6 hours to form a closed-cell foam;
- softening the foam by heating at a temperature in the range of 150 degrees F. to 250 degrees F.;
- compressing and crushing the softened foam to open the cells;
- and
- reexpanding the crushed open-celled foam by heating to a temperature in the range of 150 degrees F. to 250 degrees F.
4 more elements
A rigid porous deformation resisting, non-resilient, inflexible, rigid plastic thermoset resin foam structure having macroscopic open cells formed by,
- admixing a modified polyepoxide produced by reacting a polyepoxide having a ##STR9## equivalency in the range of 175 to 210 produced by reacting bisphenol A and epichlorohydrin, a polyamide curing and hardening agent for polyepoxides produced by condensing a polybasic carboxylic acid having from 1 to 26 carbon atoms in the molecule with a polyamine formed from a polymerizable amine having from 2 to 26 carbon atoms in the molecule in an amount from 0.2 to 2 parts by weight per 100 parts by weight of said polyepoxide;
- said reacting being carried on at a temperature in the range of 180 degrees F. to 220 degrees F. for a period of from 1/2 to 11/2 hours;
- ligroine in an amount in the range of 7 to 9 parts by weight;
- 4. 4' diamino diphenyl methane in an amount in the range of 23 to 27 parts by weight;
- a blowing agent mixture of a polyepoxide having a ##STR10## equivalency in the range of 175 to 210, and N,N' dimethyl N,N' dinitrosoterephthamide in an amount of 1 part by weight per 3 parts by weight of said polyepoxide, said blowing agent mixture being present in an amount in the range of 23 to 27 parts by weight;
- a plasticizer comprising a liquid mixture of polysulfide polymers produced by condensing an alkaline polysulfide with a dihalide in an amount in the range of 9 to 11 parts by weight;
- and
- triethylene tetramine in an amount in the range of 2 to 3 parts by weight, each per 100 parts by weight of modified polyepoxide;
- gelling the resulting mixture in a mold by maintaining the same at a temperature in the range of 50 degrees F. to 90 degrees F. for a period in the range of 8 to 16 hours.
- force foaming and partially curing the resultant gelled product by heating the same to a temperature in the range of 110 degrees F. to 130 degrees F. for an interval in the range of 3 to 5 hours;
- heating the mixture at a temperature in the range of 140 degrees F. to 160 degrees F. for an interval in the range of 3 to 5 hours;
- and
- subsequently heating the mixture to a temperature in the range of 190 degrees F. to 210 degrees F. for a period in the range of 50 to 70 minutes for each inch of thickness of the resulting closed-cell product;
- softening the product to a temperature in the range of 195 degrees F. to 205 degrees F.;
- compressing the closed-cell product to approximately one-half the original expanded thickness to cause the walls forming the closed cells to rupture to produce an open-celled product;
- reexpanding the open-celled foam material by heating to a temperature in the range of 210 degrees F. to 215 degrees F. and maintaining the temperature for an interval in the range of 10 to 30 minutes.
13 more elements
A method of producing a deformation resisting, non-resilient, inflexible, rigid plastic thermosetting foam structure having open cells comprising:
- admixing a modified polyepoxide produced by reacting a polyepoxide having a ##STR11## equivalency in the range of 175 to 210 produced by reacting bisphenol A and epichlorohydrin, a polyamide curing and hardening agent for polyepoxides produced by condensing a polybasic carboxylic acid having from 1 to 26 carbon atoms in the molecule with a polyamine formed from a polymerizable amine having from 2 to 26 carbon atoms in the molecule in an amount from 0.2 to 2 parts by weight per 100 parts by weight of said polyepoxide;
- said reacting being carried on at a temperature in the range of 180 degrees F. to 220 degrees F. for a period of from 1/2 to 11/2 hours;
- ligroine in an amount in the range of 7 to 9 parts by weight;
- 4. 4' diamino diphenyl methane in an amount in the range of 23 to 27 parts by weight;
- a decomposable activated blowing agent adapted to produce N.sub.2, CO.sub.2, and NH.sub.3 (trace) gases, said blowing agent mixture being present in an amount in the range of 23 to 27 parts by weight;
- a plasticizer comprising a liquid mixture of polysulfide polymers produced by condensing an alkaline polysulfide with a dihalide in an amount in the range of 9 to 11 parts by weight;
- and
- triethylene tetramine in an amount in the range of 2 to 3 parts by weight, each per 100 parts by weight of modified polyepoxide;
- gelling the resulting mixture in a mold by maintaining the same at a temperature in the range of 50 degrees F. to 90 degrees F. for a period in the range of 8 to 16 hours;
- force foaming and partially curing the resultant gelled produced by heating the same to a temperature in the range of 110 degrees F. to 130 degrees F. for an interval in the range of 3 to 6 hours;
- heating the mixture at a temperature in the range of 140 degrees F. to 160 degrees F. for an interval in the range of 2 to 5 hours;
- and
- subsequently heating the mixture to a temperature in the range of 190 degrees F. to 210 degrees F. for a period in the range of 50 to 70 minutes for each inch of thickness of the resulting closed-cell product;
- softening the product at a temperature in the range of 280 degrees F. to 300 degrees F.;
- compressing the closed-cell product to approximately one-half the original expanded thickness to cause the walls forming the closed cells to rupture to produce an open-celled product;
- reexpanding the open-celled foam material to its original thickness by heating to a temperature in the range of 280 degrees F. to 300 degrees F. and maintaining the temperature for an interval in the range of 10 to 30 minutes.
13 more elements
A rigid porous deformation resisting, non-resilient, inflexible, rigid plastic thermoset resin foam structure having macroscopic open cells formed by,
- admixing a modified polyepoxide produced by reacting a polyepoxide having a ##STR12## equivalency in the range of 175 to 210 produced by reacting bisphenol A and epichlorohydrin, a polyamide curing and hardening agent for polyepoxides produced by condensing a polybasic carboxylic acid having from 1 to 26 carbon atoms in the molecule with a polyamine formed from a polymerizable amine having from 2 to 26 carbon atoms in the molecule in an amount from 0.2 to 2 parts by weight per 100 parts by weight of said polyepoxide;
- said reacting being carried on at a temperature in the range of 180 degrees F. to 220 degrees F. for a period of from 1/2 to 11/2 hours;
- ligroine in an amount in the range of 7 to 9 parts by weight;
- 4. 4' diamino diphenyl methane in an amount in the range of 23 to 27 parts by weight;
- a decomposable activated blowing agent adapted to produce N.sub.2, CO.sub.2, and NH.sub.3 (trace) gases, said blowing agent mixture being present in an amount in the range of 23 to 27 parts by weight;
- a plasticizer comprising a liquid mixture of polysulfide polymers produced by condensing an alkaline polysulfide with a dihalide in an amount in the range of 9 to 11 parts by weight;
- and
- triethylene tetramine in an amount in the range of 2 to 3 parts by weight, each per 100 parts by weight of modified polyepoxide;
- gelling the resulting mixture in a mold by maintaining the same at a temperature in the range of 50 degrees F. to 90 degrees F. for a period in the range of 8 to 16 hours;
- force foaming and partially curing the resultant gelled product by heating the same to a temperature in the range of 110 degrees F. to 130 degrees F. for an interval in the range of 3 to 6 hours;
- heating the mixture at a temperature in the range of 140 degrees F. to 160 degrees F. for an interval in the range of 2 to 5 hours;
- and
- subsequently heating the mixture to a temperature in the range of 190 degrees F. to 210 degrees F. for a period in the range of 50 to 70 minutes for each inch of thickness of the resulting closed-cell product;
- softening the product to a temperature in the range of 280 degrees F. to 300 degrees F.;
- compressing the closed-cell product to approximately one-half the original expanded thickness to cause the walls forming the closed cells to rupture to produce an open-celled product;
- reexpanding the open-celled foam material to its original thickness by heating to a temperature in the range of 280 degrees F. to 300 degrees F. and maintaining the temperature for an interval in the range of 10 to 30 minutes.
13 more elements
A method of producing a deformation resisting, non-resilient, inflexible, rigid, plastic thermosetting foam structure having open cells comprising:
- foaming and partially curing a foamable, curable resin mixture to a B-stage state of cure, the foam becoming rigid in the partial cure and having closed cells;
- softening the partially cured foam;
- compressing to crush the foam material to a thickness less than its original thickness in order to cause the walls forming the cells to rupture to produce an open-celled structure;
- and
- reexpanding the compressed open cell foam material.
2 more elements
Dependencies are inferred from the claim text.