CONTAINER MODIFICATIONS TO MINIMIZE DEFECTS DURING REACTIVE POLYURETHANE FLOW

摘要

A method of reducing the number or size of voids in a polyurethane comprises reacting the formulation components in a container having an inner surface, or having a liner that has an inner surface, that has been modified to reduce the shear forces that normally accompany introduction of such components into a container. This is done by modifying the inner container's or container liner's surface by profiling and/or engraving it, or by including as a liner a mesh. The profiling and/or engraving or mesh serves to alter the formulation's flow dynamics such that the polyurethane has fewer and/or smaller voids, i.e., has a more uniform density, than polyurethanes formed without the modification.

主权项

1. A method of reducing the number or size of voids in a polyurethane formed in situ in a container, comprising forming a flow of at least two reactive polyurethane formulation components from a component source such that at least a portion of the flow contacts an inner surface of a container or of a liner thereof, the inner surface being (1) modified over at least 25 percent thereof by either (a) profiling features, said profiling features each having an average height-to-surface measurement ranging from 0.5 millimeter (mm) to 20 mm; or (b) engraving features, said engraving features having a depth-to-surface measurement ranging from 0.1 mm to 0.3 mm; the profiling or engraving features being repeated at intervals that range from 2 to 5 times the height-to-surface or depth-to-surface measurement, respectively; or (2) a mesh or having a mesh interposed between the inner surface and the component source, wherein the mesh has an average pore diameter ranging from 1 mm to 40 mm; under conditions such that a polyurethane is formed, the polyurethane having fewer or smaller voids than a polyurethane formed under identical conditions but without a modified inner surface.