Abstract:
A method and apparatus for the coating of a substrate such as a polyethylene terephthalate container with a gas barrier coating of a copolymer of vinylidene chloride is disclosed. The method includes locating the container to be coated in close proximity to one or more airless spray nozzles and impacting the outside surface of the container with a stream of a stabilized aqueous polymer dispersion such as an aqueous polyvinylidene chloride dispersion. The impacting force of the stable polyvinylidene chloride dispersion on the surface of the container is sufficient to cause selective destabilization of the dispersion at the surface interface to form a gel layer containing the polymer in the continuous phase. This gel layer serves as an adhesive layer for an overlying layer of the aqueous polymer dispersion as a continuous uniform coating. The resulting wet coating does not sag or run off. The coating on the container is then dried in a controlled atmosphere to complete the gel formation throughout its thickness whereupon it is further dried to remove the water from the coating and to collapse the get to form a film without distorting the container. The dried coating is smooth, uniform and uniformly transparent. In operation, the overspray can be collected and returned to achieve greater than 95% material efficiency.
Abstract:
Articles coated with multilayers of a composition of polytetrafluoroethylene plus a specified proportion of copolymers of perfluorinated polyvinyl ether and tetrafluoroethylene, to which is optionally added a heat stable polymer with a glass-transition temperature greater than or equal to 130°C, are found to have improved durability. The proportion of the copolymer in each layer varies such that there is a maximum amount in the bottom layer with decreasing proportions in the other layer or layers.
Abstract:
The invention relates to a plastic transparency having improved resistance to cracking. Plastic transparencies have been used as airplane windows, but have been subject to cracking, especially when subjected to a high humidity environment. The disclosed plastic transparency includes a transparent sheet member and a thin resinous coating overlying the peripheral edge surface of the sheet member. The sheet member is formed of a multi-axially oriented plastic material that is absorptive of moisture, preferably polymethyl methacrylate. The edge coating has a moisture permeation rate substantially less than that of the underlying sheet member, so when the window is exposed to an environment of high or variable humidity, any moisture gradient adjacent the peripheral edge surface is reduced, and the resultant tensile stress and incidence of cracking in the window are correspondingly reduced.
Abstract:
A method and apparatus are disclosed for enabling integrated in-line synchronous hotmelt or similar adhesive coatings of web materials and simultaneously radiation-cured silicon coatings for use therewith, as for release purposes, through the use of coating and curing stations controlled with web speed and compatably with the adhesive application and hardening steps.
Abstract:
A process for the preparation of a water-impervious surface coating on a substrate comprising applying to said substrate a layer of an aqueous bitumen emulsion containing, based on dry matter, 5-55% by weight of an acrylic prepolymer, 1-15% by weight of an air-drying alkyd resin, 40-80% by weight of bitumen and optionally up to 5% by weight of additives, applying to said layer a glass fibre layer and subsequently applying to said glass fibre layer at least one layer of water-based paint. A considerable saving in labour and time is obtained by the process and the coating obtained has an increased water vapour diffusion resistance.
Abstract:
Bei einem Verfahren zur Oberflächenbehandlung von Wärmeaustauscherflächen, die mit einem thermoplastischen Kunstharz-Überzug versehen sind, werden zur Aufbringung eines festhaftenden hydrophilen Überzuges auf den Kunstharz-Überzug hydrophile Feinpartikel auftragen und diese durch Erhitzen auf eine Temperatur oberhalb des Erweichungspunktes des Kuntharzes teilweise in den Über zug eingebettet. Der Kunstharz-Überzug sollte eine Schichtdicke im Bereich von 0,05 bis 20 µm, vorzugsweise im bereich von 0,3 bis 2 µm, aufweisen. Als hydrophile Feinpartikel sind Kiesel säure, Silikate, Tonerde und/oder Calciumkarbonat mit einer Korngröße von bis zu 10 µm, vorzugsweise von bis zu 2 µm, besonders geeignet. Ihre Auftragsmenge sollte 50 bis 2000 mg/m² betragen.
Abstract:
Bei einem Verfahren zur Oberflächenbehandlung von Wärmeaustauscherflächen, die mit einem Kunstharz-Überzug versehen sind, wird zur Aufbringung eines festhaftenden hy drophilen Überzuges mit einer Dispersion nachbehandelt, die hydrophile Feinpartikel enthält und deren Dispergiermittel den Kunstharz-Überzug erweicht oder anlöst. Der Kunstharz-Überzug sollte eine Schichtdicke im Be reich von 0,05 bis 20 µm, vorzugsweise im Bereich von 0,3 bis 2 µm, aufweisen. Als hydrophile Feinpartikel sind Kieselsäure, Silikate, Tonerde und/oder Kalziumkarbonat mit einer Korn größe von bis zu 10 µm, vorzugsweise von bis zu 2 µm, beson ders geeignet. Ihre Auftragsmenge sollte 50 bis 2000 mg/m² betragen.
Abstract:
The invention deals with a process for the surface halogenation of polymeric or metallic materials. This process comprises: introducing the material into a chamber; heating the chamber and the material to a selected temperature in the range of 38°C to 93°C by recirculating the air through a heat exchanger; evacuating the system; introducing a halogen into the system in an amount (i) of up to about 10 percent in excess of the theoretical amount of halogen required to halogenate the material to a desired depth and (ii) sufficient to provide a partial absolute pressure in the system in the range of 0.007 x 10 5 Pa to 0.21 x 10 5 Pa absolute; introducing an inert gas into the system in an amount sufficient to provide a total pressure in the system of about one atmosphere; maintaining the selected temperature by recirculating the halogen/inert gas mixture through the heat exchanger; recirculating the halogen/inert gas mixture a sufficient number of times to reduce the amount of halogen to less than about 5 percent of the amount of halogen initially introduced into the system; evacuating the system; introducing air into the system to provide about atmospheric pressure; and removing the material.