GB617145A - Improvements in or relating to compositions for forming coatings and method of making the same sheet materials - Google Patents

Abstract

A composition for coating sheet materials comprises a major proportion by weight of microcrystalline wax and an aluminium soap of a higher fatty acid, said composition having been transformed from a thixotropic gel of maximum viscosity to a less thixotropic condition approaching the Newtonian condition as determined by a Brookfield Synchrolectric viscosimeter at 250 DEG F. The soap may be aluminium stearate, e.g. technical aluminium distearate, or the palmitate or oleate, preferably in amount between four and twenty per cent by weight. The microcrystalline wax preferably has a drop melting point from 130 DEG to 180 DEG F., and a needle penetration from 10 to 60 at 77 DEG F., and the composition may be compounded under controlled conditions of time, temperature and mixing to have a viscosity not less than 10,000 c.p.s. at 250 DEG F. There may also be present an embrittlement inhibitor such as tetramethylthiuram disulphide, alkylated polyhydroxyphenol and hydroquinone, or other substances such as high melting waxes, triethanol amine, ammonia, stearic or oleic acid, abietic or citric acid, opal wax, carnauba wax, paraffin wax, montan wax, beeswax, hydrogenated oils, rubber, petrolatum, mineral oils, pigments, dyes and fillers. Such compositions may be made by melting microcrystalline wax adding up to 20 per cent soap, mixing and heating to a thixotropic gel or maximum viscosity and then further heating and mixing. Or the soap may be added to the wax, a solvent added and then the mixture heated and mixed. Specified solvents are naphtha, toluol, gasoline and benzol. The compositions may be used for coating sheet materials such as metal foil and rubber hydrochloride.ALSO:A composition for coating and laminating sheet materials comprises a major proportion by weight of microcrystilline wax and an aluminium soap of a higher fatty acid together with ester gum, phenol-formaldehyde resin or an isobutylene polymer, said compositions having been transformed from a thixotropic gel of maximum viscosity to a less thixotropic condition approaching the Newtonian condition as determined by a Brookfield synchro-electric viscosimeter at 250 DEG F. The soap may be aluminium stearate, palmitate or oleate, preferably in amount between 4 and 20 per cent by weight. There may also be present tetramethyl thiuram disulphide, alkylated polyhydroxy phenol, hydroquinone, high melting waxes, trethanolamine, ammonia, stearic acid, oleic acid, citric acid, abietic acid, opal wax, carnauba wax, paraffin wax, montan wax, beeswax, hydrogenated oils, rubber, petrolatum, mineral oils, pigments, dyes, fillers and solvents such as naphtha, toluol, gasoline and benzol. It is preferred that the amount of ester gum is up to 20 per cent by weight.