GB820706A - Mould releasing agent - Google Patents

Abstract

A mould releasing agent (particularly applicable to moulding rubber) comprises a homogeneous mixture of (a) zinc, magnesium, lead or calcium oleate, oleic acid of the oleate comprising 11-16% of the composition; (b) 50-60% paraffin wax or preferably petroleum jelly; (c) 4-6% monohydric C12-20 fatty alcohol; (d) 4.5-6.7% potassium stearate, and (e) 14-26% excess stearic acid. The preferred method of preparation is to react an oxide, hydroxide or carbonate of the appropriate metal with oleic acid, mix therewith items (b) and (c), then stearic acid and finally potassium oxide, hydroxide or carbonate; the temperature of reaction is preferably 90-130 DEG (particularly 95-105 DEG ) C. The oleic acid may be in 0.25 - about 2% excess. The petroleum jelly has, typically, m.p. 115-130 DEG (preferably 120-125 DEG ) F.; the paraffin waxes, of petroleum origin, have m.p. 110 DEG to about 135 DEG F. The alcohol may be cetyl, stearyl, lauryl, myristyl or oleyl. The mould delivering agent is incorporated into rubber during the compounding stage.ALSO:A method of compounding raw rubber comprises adding thereto a mould releasing agent comprising a homogeneous mixture of (a) zinc, magnesium, lead or calcium oleate (oleic acid thereof=11-16% of composition); (b) 50-60% petroleum jelly or paraffin wax; (c) 4-6% C12-20 monohydric fatty alcohol; (d) 4.5-6.7% potassium stearate; (e) 14-26% stearic acid. In an example, said agent was prepared from zinc oxide, oleic acid, petroleum jelly, cetyl alcohol, stearic acid and caustic potash, and 0.5 parts by weight of said agent was added to a rubber containing natural rubber (15 parts), reclaimed rubber (30 parts), rubber crumb (25 parts), reinforcing furnace black (30 parts), asphalt (3 parts), zinc oxide (1 part), sulphur (1.25 parts) and cyclohexylbenzthiazyl sulphenamide (0.5 parts).ALSO:A mould release agent (particularly applicable to moulding rubber) comprises a homogeneous mixture of (a) zinc magnesium, lead or calcium oleate (oleic acid thereof = 11-16% of composition), (b) 50-60% petroleum jelly (preferred) or paraffin wax (c) 4-6% monohydric C12-20 fatty alcohol, (d) 45-67% potassium stearate, (e) 14-26% stearic acid. Said agent is preferably prepared by reacting an oxide, hydroxide or carbonate of the appropriate metal with oleic acid, mixing therewith items (b) and (c), then stearic acid and finally potassium oxide, hydroxide or carbonate; temperature of reaction is preferably 90-130 (particularly 95-105) DEG C. The oleic acid may be in ,25-about 2% excess. The petroleum jelly has typically mp. 115-130 (preferably 120-125) DEG F.; the paraffin wax, of petroleum origin, has mp. 110-about 135 DEG F. The alcohol may be cetyl, lauryl, myristyl, stearyl or oleyl. Said agent is incorporated into rubber during the compounding stage.