Preparation of moulding compositions
AssigneeBP Chemicals International Limited
InventorDavid Philip Fry
Life of this patent
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Abstract
Sheet moulding compound (S.M.C.) is made by impregnating glass fibre with hot polyester resin matrix containing a soluble gelling agent, e.g. sodium or potassium stearate which causes the matrix to gel on cooling.
Claims11
A process for the preparation of an unsaturated polyester resin based sheet or rovings moulding compound, consisting essentially of the steps of heating a liquid unsaturated polyester resin system consisting essentially of an unsaturated polyester, a copolymerisable monomer, a polymerisation initiator and a gelling agent for said unsaturated polyester resin system to an elevated temperature at which the unsaturated resin system does not form a gel but below that at which cross linking of the system occurs, said gelling agent being soluble in said mixture of unsaturated polyester and copolymerisable monomer at said elevated temperature and being capable of initiating formation of a high viscosity gel when said solution is cooled from said elevated temperature to below 30.degree.C., impregnating a fibrous reinforcement with said liquid unsaturated polyester resin system while said resin system is at said elevated temperature, and subsequently cooling the resultant moulding compound to a temperature at which the liquid unsaturated polyester resin system forms a gel.
A process for the preparation of an unsaturated polyester resin based sheet or rovings moulding compound, consisting essentially of the steps of heating a liquid unsaturated polyester resin system consisting essentially of an unsaturated polyester, a copolymerisable monomer, a polymerisation initiator and a gelling agent for said unsaturated polyester resin system to an elevated temperature at which the unsaturated resin system does not form a gel in the range of from 50.degree. to 70.degree.C. but below that at which cross linking of the system occurs, said gelling agent being soluble in said mixture of unsaturated polyester and copolymerisable monomer at said elevated temperature and being capable of initiating formation of a high viscosity gel when said solution is cooled from said elevated temperature to below 30.degree.C., impregnating a fibrous reinforcement with said liquid unsaturated polyester resin system while said resin system is at said elevated temperature, and subsequently cooling the resultant moulding compound to a temperature below 40.degree.C. at which the liquid unsaturated polyester resin system forms a gel.
Dependencies are inferred from the claim text.