| abstract |
A lubricating composition for shaping metal under heat and pressure (see Group XXII) contains a minor proportion of an anti-welding agent mixed with a polymeric organic oxygen-containing silicon compound (see Group IV (a)) which is a silicon of general formula <FORM:0600634/III/1> or a meta-silicate of general formula <FORM:0600634/III/2> in which R is the same or different hydrocarbon or substituted hydrocarbon radical and n is an integer representing the degree of polymerization. Suitable anti-welding agents are graphite, mica, vermiculite, talc, tungsten disulphide, molybdenum disulphide, silver sulphate, lead iodide, zinc oxide and calcium oxide. A suitable lubricating composition is a polymeric dimethyl silicone containing 10 per cent graphite. Minor proportions of hydrocarbon or organic solvents, e.g. petroleum ether, naphtha, mineral oil or ashphalt may be added. A lubricating test is described, the results of which illustrate the lubricating properties of di-n-propyl silicone, di-isopropyl silicone and di-lauryl silicone. Specification 572,331 is referred to.ALSO:A lubricating composition (see Group III) for shaping metal under heat and pressure (see Group XXII) contains a minor proportion of an anti-welding agent mixed with a polymeric organic oxygen-containing silicon compound which is a silicone of general formula <FORM:0600634/IV(a)/1> or a meta-silicate of general formula <FORM:0600634/IV(a)/2> in which R is the same or different hydrocarbon or substituted hydrocarbon radicals and n is an integer representing the degree of polymerisation. The monomeric or low molecular weight silicon compounds may be polymerized by heating in presence of oxygen and an acid substance such as hydrochloric, sulphuric, phosphoric or hydrofluoric acid, boron trifluoride or bromine. Specified radicals which R may represent are methyl, ethyl, n or isopropyl, n, iso, sec. or tert. butyl, amyl, hexyl, heptyl, octyl, nonyl or decyl, cyclopentyl, cyclohexyl, phenyl, benzyl, tolyl or naphthyl. The radicals may be substituted by halogen or alkoxy. Dimethyl silicone is particularly useful. Suitable anti-welding agents are graphite, mica, vermiculite, talc, tungsten disulphide, molybdenum disulphide, silver sulphate, lead iodide, zinc oxide and calcium p oxide. A suitable lubricating composition is a polymeric dimethyl silicone containing 10 per cent graphite. Minor proportions of hydrocarbon or organic solvents, e.g. petroleum ether, naphtha, mineral oil or asphalt may be added. Specification 572,331 is referred to. |