Manufacturing procedures for making high polytetrafluoroethylene content dispersions in oil for lubricant use and the compositions so produced

A fluid polytetrafluoroethylene dispersion having excellent resistance to sedimentation, said polytetrafluoroethylene dispersion, in parts by weight of the dispersion, consisting essentially of:

• (a) 20% to about 30% particulate polytetrafluoroethylene having a substantially uniform particle size distribution where about 80% of the particles are in the range from about 2 microns to about 8 microns;
• (b) about 5% to about 15% of a polymeric dispersing agent effective to disperse said polytetrafluoroethylene and comprising an ethylene-propylene copolymer reacted with N-Vinyl-pyrrolidone;
• and
• (c) the balance essentially a lubricating carrier oil.

A method of preparing a fluid polytetrafluoroethylene dispersion having excellent resistance to sedimentation, consisting essentially of the steps of:

• (a) preparing a mixture of a carrier oil and about 5 to 20% by weight of the dispersion of an ethylene-propylene copolymer containing about 0.2% of nitrogen as a dispersing agent;
• (b) adding to the mixture 15% to 30% by weight of the dispersion of particulate polytetrafluoroethylene, said polytetrafluoroethylene having a substantially uniform particle size distribution where about 80% of the particles are in the range from about 1.6 microns to about 35 microns and which on a volume basis, the average is about 4-12 microns;
• and
• (c) admixing the carrier oil, dispersing agent and particulate polytetrafluoroethylene obtained in step (b) to form said dispersion.

A fluid polytetrafluoroethylene dispersion having excellent resistance to sedimentation, said polytetrafluoroethylene dispersion, in parts by weight of the dispersion, consisting of:

• (a) 15% to about 30% particulate polytetrafluoroethylene having a substantially uniform particle size distribution where at least about 80% of the particles have a size in the range from about 1.6 microns to about 35 microns and on a volume basis, the average is about 4-12 microns;
• (b) about 5% to about 20% of an ethylene-propylene copolymer containing about 0.2% of nitrogen as a dispersing agent to disperse said polytetrafluoroethylene to provide for dispersion of said polytetrafluoroethylene;
• and
• (c) the balance substantially a lubricating carrier oil.

A fluid polytetrafluoroethylene dispersion having excellent resistance to sedimentation, said polytetrafluoroethylene dispersion, in parts by weight of dispersion, consisting of:

• (a) 22% to about 30% particulate polytetrafluoroethylene having a substantially uniform particle size distribution where about 80% of the particles are in the range from about 2 microns to about 8 microns;
• (b) about 5% to about 15% of a polymeric dispersing agent effective to disperse said polytetrafluoroethylene and comprising an ethylene-propylene copolymer reacted with N-Vinyl-pyrrolidone;
• and
• (c) the balance essentially a lubricating carrier oil.

A method of preparing a fluid polytetrafluoroethylene dispersion having excellent resistance to sedimentation and consisting of about 5% to 20% by weight of an ethylene-propylene copolymer containing about 0.2% of nitrogen as a dispersing agent and 15% to 30% by weight of the dispersion of particulate polytetrafluoroethylene, wherein said polytetrafluoroethylene has a substantially uniform particle size distribution where about 80% of the particles are in the range from about 1.6 microns to about 35 microns and which on a volume basis, the average is about 4-12 microns;

• said method comprising the steps of:
• (a) preparing a mixture of a carrier oil and about 5 to 20% by weight of the dispersion of an ethylene-propylene copolymer containing about 0.2% of nitrogen as a dispersing agent;
• (b) adding to the mixture substantially 15% to 30% by weight of the dispersion of said particulate polytetrafloroethylene;
• and
• (c) admixing the carrier oil, dispersing agent and particulate polytetrafluoroethylene of step (b) to form said dispersion.