Patent EA-005231-B1 (EA)
Title: Thermosetting resin-rubber composite and method and apparatus for the manufacture thereof
Inventor: CAPPI GUISEPPI
IPC: C08L61/06
Filed: 2002-02-07
Abstract: 1. A thermosetting resin composition comprising: a particulate thermosetting phenol-aldehyde resin; and a particulate curing agent for said thermosetting resin, said curing agent being encapsulated in a water insoluble thermoplastic resin having a softening point higher than, (1) the melting point of said thermosetting resin and, (2) the temperature at which said thermosetting resin flows on a solid substrate, said encapsulating thermoplastic resin also being dissolvable in said thermosetting resin by heating; said curing agent being capable of curing said thermosetting resin upon melting of said encapsulating thermoplastic resin and release thereof. 2. The thermosetting resin composition of claim 1 wherein said encapsulated curing agent comprises particles dispersed substantially homogeneously throughout said thermosetting resin. 3. The thermosetting resin composition according to claim 1, wherein said encapsulated curing agent is a microcapsule-type curing agent being an emulsion-type microcapsule curing agent formed from an emulsion containing said curing agent and said water insoluble thermoplastic resin as a particle material. 4. The thermosetting resin composition according to claim1, wherein said encapsulated curing agent has a mean particle diameter in the range of 30 mum to 50 mum. 5. The thermosetting resin composition of claim 1 wherein said particulate thermosetting resin has a mean particle diameter in the range of 30 mum to 50 mum. 6. The thermosetting resin composition according to claim 1 wherein said thermoplastic encapsulating agent is a propylene/ethylene/butadiene block copolymer, polyamide, melamine, epoxy, styrene and acrylic, glycidal and acrylic copolymer. 7. The thermosetting resin composition according to claim 1 wherein said curing agent is hexamethylentetramine, paraformaldehyde, hexamethoxymelamine, trimellitic anhydride, an epoxy resin, a phenol resolic resin, a melamine resin, a prereacted epoxy-polyester resin, meta-triphenyl phosphine and quartenary ammonium salt. 8. The thermosetting resin composition according to claim 1 comprising a prepreg containing said thermosetting resin and said encapsulated curing agent. 9. The thermosetting resin composition of claim 1 wherein said phenol-aldehyde resin is a novolac. 10. The thermosetting resin composition of claim 1 wherein said phenol-aldehyde resin is a novolac having a molecular weight between about 300 and 2000. 11. The thermosetting resin composition of claim 1 wherein said phenol-aldehyde resin is a novolac formed by formed by condensation of a phenol component comprising at least one bifunctional phenol with at least one aldehyde component represented by the formula: R-CHO wherein R represents a hydrogen atom, a methyl group or a halogenated methyl group. 12. The thermosetting resin composition of claim 11 wherein said phenol-aldehyde resin is a phenol-formaldehyde resin. 13. The thermosetting resin composition of claim 1 wherein at least one particle of said particulate encapsulated curing agent is adhered to at least one particle of said thermosetting resin. 14. A curing agent for a thermosetting phenol-aldehyde resin, said curing agent being encapsulated in a water insoluble thermoplastic resin having a softening point higher than, (1) the melting point of said thermosetting resin and, (2) the temperature at which said thermosetting resin flows on a solid substrate, said encapsulating thermoplastic resin also being dissolvable in said thermosetting resin by heating; said curing agent being capable of curing said thermosetting resin upon melting of said encapsulating thermoplastic resin and release thereof. 15. The curing agent of claim 14 in particulate form. 16. The curing agent of claim 15 comprising particles having a mean particle diameter in the range of 30 mum to 50 mum. 17. The curing agent of claim 14 wherein said encapsulating curing agent is a microcapsule-type curing agent being an emulsion-type microcapsule curing agent formed from an emulsion containing said curing agent and said water insoluble thermoplastic resin as a particle material. 18. A method for curing a thermosetting phenol-aldehyde resin comprising contacting said resin with the curing agent of claim 14 and heating said resulting combination to a temperature above the melting point of said encapsulating thermoplastic resin. 19. The method of claim 18 wherein said thermosetting resin is in particulate form. 20. The method of claim 18 wherein said curing agent comprises particles substantially homogeneously distributed throughout said thermosetting resin. 21. The method of claim 18 wherein said curing agent comprises particles having a mean particle diameter in the range of 30 mum to 50 mum. 22. The method of claim 18 wherein said particulate thermosetting resin has a mean particle diameter in the range of 30 mum to 200 mum. 23. The method of claim 19 wherein at least one particle of said particulate encapsulated curing agent is adhered to at least one particle of said thermosetting resin. 24. The method of claim 18 wherein said combination is cured in the presence of a substrate that is substantially chemically inert with respect to said thermosetting resin and said curing agent. 25. The method of claim 24 resulting in the formation of a composite material comprising cured thermoset resin and said substrate. 26. The method of claim 25 wherein said composite comprises said substrate substantially surrounded by a matrix comprising said thermoset resin. 27. The method of claim 25 wherein said substrate is fiberglass. 28. A process for producing materials consisting of a mass of mutually linked inorganic fibers, comprising linking the fibers at localized fiber-fiber junctions or knots by distributing particles of a binding material and of a cross linking agent within the fiber mass and activating said binding material and cross linking agent be heating said material and agent to their respective melting temperatures, wherein said cross linking agent has a higher melting point than said binding material. 29. A process according to Claim 28, wherein said binding material and said cross linking agent are in the form of a powder. 30. A process according to Claim 28, wherein said binding material is in the form of an aqueous dispersion (slurry) of a phenolic resin. 31. A process according to Claim 28, wherein said binding material consists of a phenolic resin and said cross linking consists of a derivative of formaldehyde coated with a film of material having a melting point higher than that of the phenolic resin. 32. A process according to Claim31, wherein said formaldehyde derivative consists of a hexamethylenetetramine powder encapsulated in a coating of a material having a higher melting point than the said phenolic resin, said coating comprising a block copolymer of the propylene-ethylene-butylene type. 33. A process according to Claim 32, characterized in that said binding material consists of a phenolic resin and that said cross linking agent is chosen from among one or more of the following compounds: -paraformaldehyde - hexamethoxymelamine - trimellitic anhydride - epoxy resins - resol-type phenolic resins - melamine resins - prereacted epoxy-polyester resins. 34. Apparatus for producing a mass of mutually linked inorganic fibers comprising a first furnace for melting glass inorganic material, a die connected to said furnace for obtaining a flow of molten glass, a rotatable spinneret disposed to receive said flow and form a plurality of glass fibers passed through openings in the spinneret as it is rotated, flame deflectors disposed in the path of the fibers for directing heat on the fibers passed onto a conveyor belt disposed below the fibers and means adjacent the fibers for simultaneously dispersing a of binding material and a powdered cross linking agent within the mass formed by said fibers prior to the fibers being passed onto the conveyor belt. 35. Apparatus according to Claim 34, characterized in that it also contains a second furnace for receiving the fibers on the conveyor belt and heating said fiber up to the melting temperature of said binding material and said cross linking agent, respectively. 36. Apparatus according to Claim 35, wherein said second furnace comprises two sections through which said fibers pass, each said section adapted to operate at a different temperature, the second section having an operating temperature greater than the operating temperature of the first section.