GB967928A - Packaging unit and process for making same - Google Patents

Abstract

A packaging unit comprises a container with two or more chemicals capable of reacting with each other upon contact, and a barrier layer temporarily separating adjacent components, said layer consisting of a material which is chemically incompatible with each of the adjacent components individually but is soluble in or fusible with their reaction product so as to become completely assimilated thereby. Numerous examples of components are given and in Example I component A, the top layer, comprises 70 parts polyamide resin; Component B, the bottom layer, comprises 100 parts epoxy resin, 70 parts silica and 50 parts barytes; and the barrier layer C comprises 20 parts non-drying alkyd and 7 parts carbon black. The epoxy resin is formed by any diepoxy reaction between a polyhydroxy compound and either epichlorohydrin or dichlorohydrin. The non-drying alkyd is of the type marketed as "Paraplex G-20" and a suitable polyamide is "Versamid". In Example II Barrier C comprises 20 parts coal-tar derivative and 7 parts titanium dioxide; in Example III 20 parts chlorinated wax and 3-7 parts pigment; in Example IV 20 parts chlorinated polyphenyls and pigments as required; in Example V 20 parts terpene polymers and pigments; in Example VI 20 parts petrolatum and pigments; in Example VII 10 parts chlorinated wax, 10 parts microcrystalline wax and pigments; and in Example VIII a 30% solution in acetic ester of cellulose acetobutyrate of viscosity value 1/2 sec. and pigments. In all the Examples II-VIII the components A and B are as in Example 1. In Example IX component A comprises 35 parts ricinoleyl alcohol, 100 parts whiting, 30 parts tributyl phosphate and 10 parts colloidal silica; barrier C comprises 30 parts epoxy ester and 50 parts whiting; and component B 100 parts prepolymer of urethane, 50 parts whiting, 15 parts colloidal silica and 20 parts plasticizer (e.g. chlorinated biphenyls). In Example X component A comprises 100 parts ricinus oil, 100 parts whiting and 10 parts colloidal silica; barrier C comprises 20 parts "Piccopale" resin and 50 parts whiting; and component B 100 parts polyisocyanate, 50 parts whiting, 15 parts colloidal silica, and 20 parts plasticizer (e.g. tributyl phosphate). "Piccopale" is a hydrocarbon resin produced by the polymerization of unsaturated compounds resulting from a petrol-refining process; and in this Example X the barrier may comprise halogenated wax, halogenated polyphenyls, terpene polymers, non-drying alkyds and coal-tar derivatives as previously described. In Example XI component A comprises 7.5 parts lead dioxide, 6 parts dibutyl phthalate and 1 part stearic acid; barrier C comprises 10 parts chlorinated biphenyls, 10 parts chlorinated wax, and 3 parts stearic acid; and component C comprises 100 parts polyalkylene polysulphide, 30 parts whiting, 3 parts carbon black, and 10 parts titanium dioxide. Other compounds which may be incorporated into a barrier layer between the polyalkylene polysulphide and its activation include polyisobutylene, "Piceopale" resin, epoxy ester and terpene polymers. In Example XII three components A1, A11, and B are separated by barrier layers C1 and C11 respectively. In this example component A1 comprises 40 parts tertiary amine; barrier C1 comprises 20 parts chlorinated biphenyls; component A11 comprises 130 parts polyalkylene polysulphide, 20 parts colloidal silica and 50 parts calcium carbonate; barrier C11 20 parts chlorinated wax; and component B 130 parts epoxy resin, 20 parts colloidal silica and 50 parts calcium carbonate. The polyalkylene polysulphides are produced by the reaction between dichlorodiethylformal and are alkali polysulphide, as liquid polymers, water dispersed latices and emulsions, organic polysulphide rubbers and related forms. Component A1 may include a substituted aminomethylphenol. The barrier layer may impart some property to the mixture and may be composed of a pigmentatious matter, a refractory material to enhance fire-retarding properties, a viscosity modifier, a drying inhibitor or accelerator, or a substance capable of modifying the structural strength of the mixture or imparting thixotropic properties thereto.