This invention relates to the impregnation of rigid porous articles, particularly metal castings. In its preferred form the impregnant is a liquid mixture of monofunctional (meth)acrylic ester and a relatively small proportion of polyfunctional (meth)acrylic ester to provide a cross linked product on curing and to facilitate washing of the casting with water and an emulsifier. A peroxy or other free radical catalyst such as AZBN is associated in the impregnant with an inhibitor such as a hydroquinone derivative so that curing can be effected at a temperature of 90.degree. C. within 3 to 15 minutes. Curing is preferably effected by immersion in a hot water bath.
A process of forming a film of a fluorine-containing resin on a surface of a metallic substrate, wherein the substrate is coated with the fluorine-containing resin and is placed in a furnace vacuumized to a predetermined degree within a range containing the order of 10.sup.-3 Torr. The vacuumized atmosphere in the furnace is heated at a predetermined heating temperature of the range of from about 330.degree. C. to about 420.degree. C. for a predetermined period of time, whereupon the hot vacuumized atmosphere in the furnace is allowed to cool spontaneously with a vacuum of preferably the same degree maintained in the furnace until the temperature in the furnace reaches a predetermined pre-quenching temperature lower than the heating temperature and, thereafter, an inert gas at ambient temperature is introduced into the furnace for quenching the coating on the substrate.
A composition of matter which is useful in a process for impregnating and sealing of porous articles, the composition comprising: (a) an azonitrile; (b) a polymerizable acrylic monomer; (c) a substituted, sterically-hindered phenol; and (d) a metal ion chelator.
A method of impregnating a porous article with impregnant to seal the pores thereof, which comprises placing the article in a vessel, evacuating the vessel to withdraw air from the pores, releasing the vacuum with the pores beneath the surface of a liquid impregnant in the vessel, removing excess impregnant from the vessel, washing excess impregnant from the surface of the article by supplying washing fluid to the vessel, removing the fluid from the vessel, heating the article while still within the vessel to effect curing of the impregnant within the pores, and removing the impregnated article from the vessel.
A process for impregnating a porous part is provided. In one embodiment, the process comprises impregnating the part with an impregnant that is not water soluble, and curing the impregnated part in a water bath. In another embodiment, the process comprises impregnating a part with an impregnant that is not water soluble, washing the impregnated part in a washing solution, and then curing the impregnated part in a water bath.
A resin cleaner composition is provided herein for use as a cleaning solvent to remove cured, partially cured and uncured polyester or vinyl ester resin containing a free radical polymerization initiator from resin fabrication tools. The composition is characterized by the presence therein of a free radical inhibitor which suppresses the rate of free radical polymerization. Thereby the resin can be loaded in increased amounts in the composition without an accompanying increase in polymerization of the resin.
