Method of thickening phenolic resin and use thereof to form vehicle components
A method of building viscosity in a sheet molding composition is provided that includes a thickening agent of at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxides, zinc oxide, borates, aluminum ion chelates, aluminum trihydrate, polyphosphate, epoxides being mixed into a phenolic resin liquid or solution that includes novolac resin. An initial viscosity results for the mixture. The viscosity builds from the initial viscosity to 36 hours, from 36 to 142 hours, and then from 142 hours to 176 hours to define a slope ratio of viscosities in these time ranges of 1.5-8:1:−0.4-2 and a having terminal viscosity as measured at 176 hours. Alternatively, the initial viscosity is between 500 and 50,000 centiPoise (cP) and at 24 hours thereafter builds to between 1 million to 50 million cP, and the terminal viscosity thereafter of between 10 million and 200 million cP.
1 . A method of building viscosity in a sheet molding composition comprising:
mixing into a phenolic resin liquid or solution, a thickening agent of at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxides, zinc oxide, borates, aluminum ion chelates, aluminum trihydrate, polyphosphate, epoxides or combinations thereof, with the proviso that novolac-phenolic resin is present in said phenolic resin liquid or solution, to define an initial viscosity for a mixture; and
allowing viscosity of said mixture to build from the initial viscosity such that:
the initial viscosity is between 500 and 50,000 centiPoise (cP) and at 24 hours thereafter builds to between 1 million to 50 million cP, and a terminal viscosity thereafter is between 10 million and 200 million cP, wherein the phenolic resin of the phenolic resin liquid or solution includes novolac-phenolic resin and resol-phenolic resin in a weight ratio of (greater than 1 but less than or equal to 2):1.
2 . The method of claim 1 wherein the terminal viscosity is between 10 million and 100 million cP.
3 . The method of claim 1 wherein said phenolic resin of the phenolic resin liquid or solution is liquid at 20° C. and standard atmospheric pressure.
4 . The method of claim 1 wherein the resol-phenolic resin is provided as a liquid, aqueous solution or alcoholic solution.
5 . The method of claim 1 wherein the novolac-phenolic resin has an average molecular weight between 250 and 1200.
6 . The method of claim 1 wherein the resol-phenolic resin has an average molecular weight between 200 and 750.
7 . The method of claim 1 wherein said thickening agent is magnesium oxide.
8 . The method of claim 1 wherein said thickening agent is present from 0.5 to 10 percent by total weight.
9 . The method of claim 1 wherein said mixing is mechanical mixing with concurrent heating.
10 . The method of claim 1 further comprising dispersing in the mixture at least one of reinforcing fibers, inert filler particles, microspheres, or a low profile additive.
11 . The method of claim 1 further comprising curing said phenolic resin into a shape in a mold.
12 . The method of claim 11 wherein the mold has a cycle time of from 45 to 180 seconds to form an article.
13 . The method of claim 11 wherein the shape defines a vehicle battery box of or portion thereof.
14 . The method of claim 11 wherein the shape defines a vehicle component of a firewall barrier, a bumper beam, an automotive door intrusion beam, an automotive door panel component, an automotive hood, an automotive trunk lid, an automotive load floor component, a pick-up box, a railcar component, a HVAC component, electrical component, or an aerospace component.
15 . A method of building viscosity in a sheet molding composition comprising:
mixing into a phenolic resin liquid or solution, a thickening agent of at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxides, zinc oxide, borates, aluminum ion chelates, aluminum trihydrate, polyphosphate, epoxides or combinations thereof, with the proviso that novolac-phenolic resin is present in said phenolic resin liquid or solution, to define an initial viscosity for a mixture; and
allowing viscosity of said mixture to build from the initial viscosity such that:
said viscosity from the mixing to 36 hours, from 36 to 142 hours, and from 142 hours to 176 hours define a slope ratio of 1.5-8:1:-0.4-2 with a terminal viscosity measured at 176 hours.
16 . The method of claim 1 , wherein the sheet molding composition includes between two volume percent and 33 volume percent hollow glass microspheres, the hollow glass microspheres having a mean diameter between 10 and 55 microns.
17 . The method of claim 15 wherein the phenolic resin of the phenolic resin liquid or solution includes novolac-phenolic resin and resol-phenolic resin.
18 . The method of claim 17 wherein the novolac-phenolic resin and the resol-phenolic resin are present in a weight ratio of (greater than 1 but less than or equal to 2):1.