17 Resins in the form of powder, bars, blocks, pellets, rods, sheets and tubes, and extruded forms for use in further manufacture; resins in the form of powder, bars, blocks, pellets, rods, sheets and tubes, for general industrial use; synthetic resinous polymers for use in the general industrial arts being semi finished products, plastics in the form of sheets, blocks and rods, being for use in manufacture