Abstract:
A process of producing a high gloss oxidizable extrusion coated polyethylene is provided. This process entails extrusion coating a low density polyethylene of narrow molecular weight distribution having a low melt index, a low swell ratio, and a polydispersity index below 9.
Abstract:
A process for permanently attaching smooth finished globules of coating material to the ends of the teeth of molded plastic combs, picks, lifts and the like, including roughening or oxidizing the teeth ends to remove the gloss finish and form a more adherent surface; dipping the roughened teeth ends into a bath of liquid coating material to attach a globule of coating material to each tooth end and cover the sharp mold-parting line located thereat; and drying the globules attached to the teeth ends.
Abstract:
A method and apparatus for coating a hollow article with at least two coating materials, said method comprising the steps of applying a first coating material to the article and drying or partially curing at least the surface of the first coating before the application of the second material. Thereafter the two coatings may be fully cured together or alternatively the second coating material may be partially cured in readiness to receive a further coating. The preferred curing means is a gas flame.
Abstract:
Disclosed herein is a cylinder produced by a method of providing on the outer surface of an inner cylindrical member an epoxy coating of substantially uniform radial thickness. More particularly, the coated member is a roto-gravure printing cylinder.The method comprises the steps of applying an innermost layer of an uncured mixture of an epoxy resin and a hardener to the outer surface of the member to a depth which is less than the desired coating thickness, applying at least one additional layer of the uncured mixture to the outer surface of an already applied layer, such that the total depth of all layer is at least as great as the thickness, heating the outermost layer after the application thereof to eliminate its porosity, and after the applying steps allowing the layers to cure to form the coating. The total depth of the layers is disclosed as greater than the thickness and the method includes, after curing, the further step of machining the outer surface of the cured epoxy to reduce the depth thereof to the desired radial thickness.The apparatus comprises a holding device having an axis for gripping the member and rotating the same about its axis, a source of supply of the mixture, a mixture extruding tube connected to the supply and having extruding orifices parallel to the axis of the holding device for applying the mixture as aforesaid, and a ribbon burner parallel to the axis of the gripping means for directing a flame against the applied layers.
Abstract:
A process of bonding a coating of a polyurethane resin to a polyolefin substrate is provided. The polyolefin substrate is coated with a graft copolymer of a polyolefin and a functional monomer such as acrylic acid. The graft copolymer is flame treated to fuse it. A liquid polyurethane precursor composition is then applied thereto and cured.
Abstract:
A method for coating a cylindrical container with a thin, resinous coating by spraying powdered resin is disclosed. The technique involves spraying of finely divided resin particles at a velocity of at least about 200 feet per minute from a spray nozzle external to the container into the interior of a rapidly revolving container, particularly slender, cylindrical containers. The container may be sprayed by directing a pulse of a predetermined quantum of resin into the container to deposit a substantially uniform coating. Alternatively, a continuous flow of resin at a predetermined rate may be sprayed into a container. The resin particles are caused to adhere to the container by preheating the container. The coating is rendered continuous by preheating the container to temperatures above the softening point of the resin. Postheating of the coated container at temperatures in excess of about 300.degree. F matures the coating.