Improvements in the production of adherent or removable liners for hollow articles

Abstract

Abstract <PICT:0591611/III/1> Adherent liners for hollow articles, e.g., pipes, metal valves, pump bodies and acid eggs, are made by partly or completely filling a hollow article with a composition comprising a dispersion of vinyl chloride polymer in a non-volatile plasticizing agent in which it is from scarcely soluble to insoluble at room temperature, e.g., dibutyl phthalate or tri-cresyl phosphate, and gelling a layer of the composition adjacent to the surface to be lined by the application of heat to the surface and then removing the ungelled composition. The article is preferably previously heated, before filling, to a temperature of 90 DEG to 150 DEG C. After removal of the ungelled composition the article with its adherent liner may be baked, e.g., at 90 DEG to 150 DEG C. To make a lining for a flanged pipe 1, a blank flange 2 is bolted to the pipe with a spacing ring 3 between the two flanges. A spacing ring 5 is placed on the top of the pipe. A bung 4 is fitted in the lower end of the pipe and the pipe heated to 150 DEG C. and then filled with composition. After 2 1/2 minutes the bung is removed and the pipe and its newly formed liner baked for 20 minutes at 150 DEG C. Detailed examples of various compositions for making liners are given. Specifications 500,298 and 589,715, [both in Group IV], are referred to.ALSO:Hollow articles or adherent liners for hollow articles, e.g pipes, metal valves, pump bodies and acid eggs, are made by partly or completely filling a hollow article or mould with a composition comprising a dispersion of vinyl chloride polymer in a non-volatile plasticising agent in which it is from scarcely soluble to insoluble at room temperature, e.g. dibutyl phthalate or tricresyl phosphate, and gelling a layer of the composition adjacent to the surface to be lined or the surface of the mould by the application of heat to the surface and then removing the ungelled composition. The article or mould is preferably previously heated, before filling, to a temperature of 90 DEG to 150 DEG C. After removal of the ungelled composition the article with its adherent liner may be baked, e.g. at 90 DEG to 150 DEG C. Detailed examples are described for making liners for pipes with various compositions and for making a doll's head, a T junction piece and a bottle. The compositions used include a dispersion of 51 parts of finely powdered polyvinyl chloride in a mixture of 21 parts of dibutyl phthalate, 21 parts of chlorinated paraffin wax and 7 parts of tetrahydronaphthalene. Specifications 500,298 and 589,715 are referred to.

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