Method for co-reactive extrusion coating of pipe using thermosetting material
AssigneeW. R. Grace & Co.-Conn.
InventorsCung Vu, Matthew T. Pickett
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Abstract
The method of the invention for co-reactive slot die extrusion coating of elongated tubular articles, such as pipes, comprises the steps of extruding a two-component thermosetting material through a slot die that is comprised of low friction material and so configured as to permit the slot die to be rapidly opened for purposes of peeling gelled material from the die by hand. The method provides for substantially increased coverage rates and the use of interchangeable and reusable slot dies. In a preferred method, the extrusion step campuses the use of a slot die comprised of two blocks comprised of an acetal resin, and the blocks are clamped together and can be quickly unclamped to permit convenient removal of gelled thermoset material.
Claims13
A method for coating a pipe, comprising the steps of:
- introducing two thermoset components A and B each separately into a proportioning pump operative to meter said components in a ratio said components, when combined, operative to form a material selected from the group consisting of epoxy, polyurethane, and silicone;
- providing a metering pump in conjunction with said proportioning pump to ensure that after metering said thermoset components A and B are sufficiently intermixed to initiate a thermosetting reaction;
- extruding onto a continuously rotating pipe said intermixed reacting components through a slot die having a body comprised of at least two blocks defining therebetween inner passageway surfaces comprised of low-stick material operative to permit said reacting thermosetting components, when gelled and thermoset, to be removed therefrom, said blocks being releasably attached to each other whereby said slot die can be dismantled and thermoset material can be removed from within said inner passageway surfaces, and said extruded intermixed reacting components having a coating coverage rate for coating said continuously rotating pipe;
- and
- advancing said slot die longitudinally along the length of said pipe while said pipe is rotated, whereby a ribbon of thermosetting material is helically coated around said pipe and is operative to protect said pipe against corrosion,
A method for coating a pipe, comprising the steps of:
- introducing two thermoset components A and B separately into a proportioning pump operative to meter said components in a desired ratio, said components, when combined, operative to form a polyurethane;
- providing a metering pump in conjunction with said proportioning pump to ensure that after metering said thermoset components A and B are sufficiently intermixed to initiate a thermosetting reaction;
- extruding onto a continuously rotating pipe said intermixed reacting components through a slot die having a body comprised of at least two blocks defining therebetween inner passageway surfaces comprised of low-stick material operative to permit said reacting thermosetting components, when gelled, and thermoset, to be removed therefrom, said slot die blocks being releasably attached to each other whereby said slot die can be dismantled, and said at least two slot die blocks further being comprised of low-stick material, said extruded intermixed reacting components having a coating coverage rate for coating said continuously rotating pipe;
- and
- advancing said slot die longitudinally along the length of said pipe while said pipe is rotated, whereby a ribbon of reacting thermosetting polyurethane material is helically coated around said pipe.
Dependencies are inferred from the claim text.