US3859162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pre-preg materials, chemically integral composite foam structures prepared therefrom, and methods of preparation
Assignee: 3M Co
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Filing: 1973-05-11
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Granted: 1975-01-07
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Expires: 1993-05-11
Abstract
Abstract Pre-preg materials and flexible tapes comprising polycarbodiimide prepolymers and a fiber reinforcing material, and reinforced, chemically integral, composite foam structures prepared from said pre-pregs. The composite structures are prepared by curing said pre-pregs in combination with additional polycarbodiimide-forming, foamable precursors by the application of heat.
Inventors
- 👤 James William Johnson
- 👤 John E Peterson
- 👤 Charles Reich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:25
CPC Classifications
B; B32; B32B; B32B5/00; B32B5/22; B32B5/24; B32B5/245; B32B5/18; B32B5/20; B32B5/26; C; C08; C08G; C08G18/00; C08G18/02; C08G18/025; C08J; C08J5/00; C08J5/24; C08J5/241; C08J5/244; C08J5/246; C08J5/248; C08J5/249; C08K; C08K7/00; C08K7/02; C08K7/04; C08L; C08L67/00; C08L67/02; C08L77/00; C08L79/00; B32B2262/00; B32B2262/10; B32B2262/101; B32B2266/00; B32B2266/02; B32B2266/0214; C08J2379/00; Y; Y10; Y10S; Y10S521/00; Y10S521/901; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249987; Y10T428/249988; Y10T428/249994; Y10T428/249998; Y10T428/26; Y10T428/266
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
50 words
A SELF SUPPORTING FIBER REINFORCED PRE-PREG COMPRISING A COHESIVE ADMIXTURE OF FIBER REINFORCING MATERIAL AND FUSED THEREON A SOLID, FLOWABLE, ISOCYANATE-CONTAINING POLYCARBODIIMIDE PREPOLYMER, SAID PREPOLYMER HAVING A CURING CATALYST DISPERSED THEREIN, SAID CATALYST CAPABLE OF CATALYZING THE REACTION BETWEEN ISOCYANATE GROUPS TO FORM CARBONDIIMIDE LINKAGES UNDER THE INFLUENCE OF HEAT.
Claim 2
Dependent Claim
50 words
A SELF SUPPORTING FIBER REINFORCED PRE-PREG COMPRISING A COHESIVE ADMIXTURE OF FIBER REINFORCING MATERIAL AND FUSED THEREON A SOLID, FLOWABLE, ISOCYANATE-CONTAINING POLYCARBODIIMIDE PREPOLYMER, SAID PREPOLYMER HAVING A CURING CATALYST DISPERSED THEREIN, SAID CATALYST CAPABLE OF CATALYZING THE REACTION BETWEEN ISOCYANATE GROUPS TO FORM CARBONDIIMIDE LINKAGES UNDER THE INFLUENCE OF HEAT.
Claim 3
Dependent Claim
20 words
A fiber reinforced pre-preg according to claim 1 wherein said prepolymer has an isocyanate equivalent weight of at least 400.
Claim 4
Independent Claim
117 words
A METHOD OF MAKING A CHEMICALLY INTEGRAL, FIBER REINFORCED, COMPOSITE FOAM STRUCTURE COMPRISING A. PROVIDING A PRE-PREG MATERIAL COMPRISING SOLID POLYCARBONIIMIDE PREPOLYMER FUSED ONTO REINFORCING FIBERS, SAID PREPOLYMER HAVING A CURING CATALSYT HOMOGENEOUSLY DISPERSED THEREIN, SAID PREPOLYMER CAPABLE OF CURING TO FORM A POLYCARBODIIMIDE POLYMER WITH THE APPLICATION OF HEAT, B. CONTACTING SAID PRE-PREG MATERIAL WITH FOAMABLE POLYCARBODIIMIDE PRECURSORS AND MAINTAINING SAID PRECURSORS ADJACENT SAID PRE-PREG MATERIAL, AND C. HEATING SAID PRE-PREG MATERIAL AND SAID FOAMABLE POLYCARBODIIMIDE PRECURSORS SUBSTANTIALLY SIMULTANEOUSLY UNDER CONDITIONS SUFFICIENT TO CAUSE FOAMING OF SAID FOAMABLE POLYCARBODIIMIDE PRECURSORS AND TO CAUSE CROSSLINKING OF SAID FUSED PREPOLYMER IN SAID PRE-PREG, AND CROSSLINKING OCCURRING ESSENTIALLY WITHOUT THE FORMATION OF AUTOGENEOUS VOIDS VISIBLE TO THE NAKED EYE.
Claim 5
Independent Claim
117 words
A METHOD OF MAKING A CHEMICALLY INTEGRAL, FIBER REINFORCED, COMPOSITE FOAM STRUCTURE COMPRISING A. PROVIDING A PRE-PREG MATERIAL COMPRISING SOLID POLYCARBONIIMIDE PREPOLYMER FUSED ONTO REINFORCING FIBERS, SAID PREPOLYMER HAVING A CURING CATALSYT HOMOGENEOUSLY DISPERSED THEREIN, SAID PREPOLYMER CAPABLE OF CURING TO FORM A POLYCARBODIIMIDE POLYMER WITH THE APPLICATION OF HEAT, B. CONTACTING SAID PRE-PREG MATERIAL WITH FOAMABLE POLYCARBODIIMIDE PRECURSORS AND MAINTAINING SAID PRECURSORS ADJACENT SAID PRE-PREG MATERIAL, AND C. HEATING SAID PRE-PREG MATERIAL AND SAID FOAMABLE POLYCARBODIIMIDE PRECURSORS SUBSTANTIALLY SIMULTANEOUSLY UNDER CONDITIONS SUFFICIENT TO CAUSE FOAMING OF SAID FOAMABLE POLYCARBODIIMIDE PRECURSORS AND TO CAUSE CROSSLINKING OF SAID FUSED PREPOLYMER IN SAID PRE-PREG, AND CROSSLINKING OCCURRING ESSENTIALLY WITHOUT THE FORMATION OF AUTOGENEOUS VOIDS VISIBLE TO THE NAKED EYE.
Claim 6
Dependent Claim
16 words
The fiber reinforced pre-preg of claim 1 wherein said fiber reinforcing material is a fiber web.
Claim 7
Dependent Claim
27 words
The fiber reinforced pre-preg of claim 1 wherein said prepolymer constitutes from 20 - 90 percent by volume of the total volume of prepolymer and reinforcing fiber.
Claim 8
Dependent Claim
29 words
The fiber reinforced pre-preg of claim 1 wherein said polycarbodiimide propolymer is capable of generating autogenous voids visible to the naked eye when cured by the application of heat.
Claim 9
Dependent Claim
30 words
The fiber reinforced pre-preg of claim 1 wherein said polycarbodiimide prepolymer is capable of cure upon the application of heat without generation of autogenous voids visible to the naked eye.
Claim 10
Dependent Claim
16 words
A pre-preg according to claim 1 wherein said prepolymer contains an additional particulate filler dispersed therein.
Claim 11
Dependent Claim
12 words
A pre-preg according to claim 7 wherein said filler comprises mica flakes.
Claim 12
Dependent Claim
13 words
A pre-preg according to claim 7 wherein said filler comprises inorganic titanate whiskers.
Claim 13
Dependent Claim
74 words
A chemically integral, fiber reinforced, composite foam structure comprising crosslinked polycarbodiimide polymer and a fiber reinforcing material, said structure comprising a. at least one first reinforcing portion, said reinforcing portion comprising fiber reinforcing material and said polycarbodiimide polymer, said reinforcing portion being essentially free of autogenous voids visible to the naked eye, and b. at least one second foamed portion comprising said polycarbodiimide polymer, said first portion being chemically integral with said second portion.
Claim 14
Dependent Claim
74 words
A chemically integral, fiber reinforced, composite foam structure comprising crosslinked polycarbodiimide polymer and a fiber reinforcing material, said structure comprising a. at least one first reinforcing portion, said reinforcing portion comprising fiber reinforcing material and said polycarbodiimide polymer, said reinforcing portion being essentially free of autogenous voids visible to the naked eye, and b. at least one second foamed portion comprising said polycarbodiimide polymer, said first portion being chemically integral with said second portion.
Claim 15
Dependent Claim
23 words
A chemically integral, fiber reinforced composite foam structure according to claim 10 wherein said reinforcing portion has a minimum thickness of 5 mils.
Claim 16
Independent Claim
117 words
A method of making a chemically integral, fiber reinforced, composite foam structure comprising a. providing a pre-preg material comprising solid polycarbodiimide prepolymer fused onto reinforcing fibers, said prepolymer having a curing catalyst homogeneously dispersed therein, said prepolymer capable of curing to form a polycarbodiimide polymer with the application of heat, b. contacting said pre-preg material with foamable polycarbodiimide precursors and maintaining said precursors adjacent said pre-preg material, and c. heating said pre-preg material and said foamable polycarbodiimide precursors substantially simultaneously under conditions sufficient to cause foaming of said foamable polycarbodiimide precursors and to cause crosslinking of said fused prepolymer in said pre-preg, said crosslinking occurring essentially without the formation of autogenous voids visible to the naked eye.
Claim 17
Independent Claim
117 words
A method of making a chemically integral, fiber reinforced, composite foam structure comprising a. providing a pre-preg material comprising solid polycarbodiimide prepolymer fused onto reinforcing fibers, said prepolymer having a curing catalyst homogeneously dispersed therein, said prepolymer capable of curing to form a polycarbodiimide polymer with the application of heat, b. contacting said pre-preg material with foamable polycarbodiimide precursors and maintaining said precursors adjacent said pre-preg material, and c. heating said pre-preg material and said foamable polycarbodiimide precursors substantially simultaneously under conditions sufficient to cause foaming of said foamable polycarbodiimide precursors and to cause crosslinking of said fused prepolymer in said pre-preg, said crosslinking occurring essentially without the formation of autogenous voids visible to the naked eye.
Claim 18
Dependent Claim
19 words
A method according to claim 12 wherein said pre-preg material is formed so as to substantially enclose said precursors.
Claim 19
Dependent Claim
48 words
A flexible, reinforced tape comprising a cohesive admixture of fiber reinforcing material and fused thereon a solid, flowable, isocyanate-containing polycarbodiimide prepolymer, said prepolymer having a curing catalyst dispersed therein, said catalyst capable of catalyzing the reaction between isocyanate groups to form carbodiimide linkages under the influence of heat.
Claim 20
Dependent Claim
48 words
A flexible, reinforced tape comprising a cohesive admixture of fiber reinforcing material and fused thereon a solid, flowable, isocyanate-containing polycarbodiimide prepolymer, said prepolymer having a curing catalyst dispersed therein, said catalyst capable of catalyzing the reaction between isocyanate groups to form carbodiimide linkages under the influence of heat.
Claim 21
Dependent Claim
18 words
A tape according to claim 14 wherein said prepolymer has an isocyanate equivalent weight of at least 400.
Claim 22
Dependent Claim
26 words
A tape according to claim 14 wherein said prepolymer constitutes from 20 - 90 percent by volume of the total volume of prepolymer and reinforcing fiber.
Claim 23
Independent Claim
102 words
A method of making a chemically integral, fiber reinforced, foamed structure comprising a. providing a flexible, reinforced tape comprising a cohesive admixture of fiber reinforcing material and fused thereon a solid, flowable, isocyanate-containing polycarbodiimide prepolymer, said prepolymer having a curing catalyst dispersed therein, said catalyst capable of catalyzing the reaction between isocyanate groups to form carbodiimide linkages under the influence of heat, b. applying said tape to a substrate, and c. heating said tape to cause foaming by the generation of carbon dioxide from the carbodiimide forming reaction of said prepolymer, and d. continuing said heating to form a crosslinked polycarbodiimide polymer.
Claim 24
Independent Claim
102 words
A method of making a chemically integral, fiber reinforced, foamed structure comprising a. providing a flexible, reinforced tape comprising a cohesive admixture of fiber reinforcing material and fused thereon a solid, flowable, isocyanate-containing polycarbodiimide prepolymer, said prepolymer having a curing catalyst dispersed therein, said catalyst capable of catalyzing the reaction between isocyanate groups to form carbodiimide linkages under the influence of heat, b. applying said tape to a substrate, and c. heating said tape to cause foaming by the generation of carbon dioxide from the carbodiimide forming reaction of said prepolymer, and d. continuing said heating to form a crosslinked polycarbodiimide polymer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |