Patent GB-834263-A (GB)
Title: Improvements in or relating to method for treating interiors of synthetic resin containers
IPC: B29C67/00
Filed: 1956-09-17
Abstract: The interior surface of a synthetic resin container is modified by igniting therein an explosive oxygen-containing mixture and then coating the surface with, for example, a film-forming resin, or a dye or pigment, or a chemical stabilizer such as anti-oxidant or anti-corrosive materials.  The container may be made of one or more resins and the resin may be a polymerization or a condensation product.  The resin may, for example, be polyethylene, e.g. Ziegler polyethylene, polyethylene terephthalate, polytetrafluoroethylene, nylon, ethylenevinyl acetate copolymer, an epoxy resin, a coumarone or indene resin, acetylene polymer, olefin and olefin-sulphur dioxide resin, phenolaldehyde resin, furfural, ketone or urea-formaldehyde resin, melamine- or dicyandiamideformaldehyde resin, sulphonamide-aldehyde resin, a resin derived from nitrogen containing heterocyclic compounds, polyester or polyamide resin, polyether resin, a polyvinyl ether, alcohol or ester, polystyrene or synthetic rubber.  The coating material may be applied, e.g., by spraying or shaking, to the interior in the form of solutions, suspensions or dispersions in a volatile liquid and the resins specified above may be used as coating materials.  The coating material may also be a polyacrylonitrile resin, acrylonitrile-styrene copolymer, polyvinyl chloride, or copolymers of methyl vinyl ether with maleic anhydride and the coating material may be dissolved in a suitable solvent such as water, low molecular weight alcohols, e.g. methyl, ethyl or propyl alcohols, toluene or methyl ethyl ketone.  In the case of thermosetting resins the coating may afterwards be cured at a raised temperature.ALSO:The interior surface of a container made of a synthetic resin is modified, to render it adherent to a coating by igniting therein an explosive oxygen-containing mixture.  Synthetic resins mentioned are polyethylene (including lowtemperature polyethylene such as Ziegler polyethylene), polytetrafluoroethylene, polyvinyl acetate, ethylene-vinyl acetate copolymers, acetylene polymers (including their halogenated derivatives), polystyrene, polymers of isoprene, butadiene, polyvinyl ethers, polyvinyl alcohols, polyvinyl esters, epoxy resins, coumarone and indene resins, resins from hydrazine, pyrazoles, pyridine, quinoline, pyrrole, indole and carbazole, olefin-sulphur dioxide resins, phenol-aldehyde, furfural, ketone, amine-aldehyde and sulphonamide-aldehyde resins, urea-formaldehyde resins such as thiourea-, melamine- or dicyandiamide-formaldehyde resins, condensation polyester resins, including those from polyhydric alcohols and polybasic acids, and from hydroxy acids, polyamide resins and derivatives thereof, mixed polyester-polyamide resins, polyether resins, polyethylene terephthalate and nylon and synthetic rubber or mixtures of these.  The above materials may be modified with any of the usual plastizers, pigments, fillers, dyes or substances which chemically combine with them.  The explosive mixture may be a mixture of a gaseous fuel such as propane, ethane or natural gas, or a liquid fuel such as gasoline or kerosene, or a solid explosive such as gun powder or dynamite with a free-oxygen supplying gas such as air and ignition may be by means of a spark.  The treated surface may be coated with a film-forming resin in the form, usually of a solution, suspension or dispersion in a volatile liquid and any of the resins mentioned above may be used or alternatively there may be used mixtures of vinyl chloride or vinyl ester-vinyl alcohol copolymers with ureaformaldehyde resins, polyacrylonitrile resins, polyamide resins such as nylon, acrylonitrile-styrene copolymers, polyvinyl alcohols, and copolymers of methyl vinyl ether with maleic anhydride.  The preferred coatings are polar ones which are cured or set after the p  coating has been applied to the surface.  The examples include (1) a solution of a mixture of polyvinyl chloride and urea-formaldehyde resin in a solvent consisting of equal proportions of toluene and methyl ethyl ketone, and (2) a solution of nylon in ethanol.  Alternatively, coatings other than film-forming resins may be applied to the interior surface, e.g. pigments or chemicals such as antioxidant or anticorrosive stabilizers.