Patent GB-621501-A (GB)
Title: Improvements in or relating to a composition of matter and method of making the same
IPC: C08L61/10
Filed: 1946-03-21
Abstract: Synthetic resin compositions suitable for making p  anti-frictional devices such as bearings and sealing washers comprise a fibrous filler, powdered metal, graphite and a thermosetting potentially reactive resin, particularly phenolformaldehyde resin, the resin constituting from 35 to 50 per cent by weight of the whole.  The fibrous filler is preferably asbestos; macerated cloth may also be used.  The powdered metal preferably has a plastic metal such as lead as major constituent, and may be an alloy containing 80-85 per cent by weight of lead, the remainder being antimony and tin, preferred proportions being 84 per cent lead, 12 per cent antimony and 4 per cent tin.  The composition preferably comprises by weight 21 to 30 parts asbestos floats, 25-30 parts powdered metal, 35-50 parts phenol-formaldehyde resin, 14-20 parts graphite and 0.3-0.7 parts zinc stearate acting as lubricant.  A machine element is formed by mixing the constituents of the composition over hot rolls, grinding the resultant product into a moulding powder, subjecting a measured quantity of the powder in a die to pressure and heat just sufficent to form a coherent mass, and then removing the element from the die and increasing its temperature in an oven until the resin is completely cured.  Moulding takes place preferably at a temperature of 200 DEG  F. and a maximum pressure of about 28,000 lbs. per sq. in., the moulding step being completed in about half a second, and the element may be cured by heating for 24 to 36 hours in the oven at a maximum temperature of about 350 DEG  F.  Specifications 565,955 and 620,153 are referred to.ALSO:Plastic compositions suitable for making antifrictional devices such as bearings and sealing washers comprise a fibrous filler, powdered metal, graphite and a thermo-setting potentially reactive resin, particularly phenol-formaldehyde resin, the resin constituting from 35 per cent to 50 per cent by weight of the whole.  The fibrous filler is preferably asbestos; macerated cloth may also be used.  The powdered metal preferably has a plastic metal such as lead as major constituent, and may be an alloy containing 80 - 85 per cent by weight of lead, the remainder being antimony and tin, preferred proportions being 84 per cent lead, 12 per cent antimony and 4 per cent tin.  The composition preferably comprises by weight 21 to 30 parts asbestos floats, 25 - 30 parts powdered metal, 35 to 50 parts phenol-formaldehyde resin, 14 - 20 parts graphite and 0.3 - 0.7 parts zinc stearate acting as lubricant.  A machine element is formed by mixing the constituents of the composition over hot rolls, grinding the resultant product into a moulding powder, subjecting a measured quantity of the powder in a die to pressure and heat just sufficient to form a coherent mass, and then removing the element from the die and increasing its temperature in an oven until the resin is completely cured.  Moulding takes place preferably at a temperature of 200 DEG  F. and a maximum pressure of about 28,000 lb. per sq. in., the moulding step being completed in about half a second, and the element may be cured by heating for 24 to 36 hours in the oven at a maximum temperature of about 350 DEG  F. Specifications 565,955, [Group IV], and 620,153, [Group IV (a)], are referred to.