A swash plate-type compressor that is frequently used as a compressor for an automotive air conditioning system comprises a swash plate secured to a rotary shaft at an inclined angle, and a plurality of shoes disposed at the front and rear sides of the swash plate and operably coupled to a piston. When the rotary shaft rotates, the disc-shaped swash plate secured to the rotary shaft rotates, and the rotary motion of the swash plate mediated by the shoes is converted to the reciprocating motion of the piston to compress, expand, and discharge a refrigerant. In the case of this swash plate-type compressor, if the metal swash plate slides relative to the shoes in an initial operating state before lubricating oil reaches the inside of a housing including a refrigerant, the sliding portion will be free of lubricating oil, thus causing a seizure phenomenon.
Japanese Unexamined Patent Application Publication No. 2009-209727 and Korean Patent No. 10-1086847 disclose a mixture of a solid lubricant such as PTFE, MoS2, WS2 or crystalline graphite, a metal oxide or silane coupling agent for increasing abrasion resistance or adhesion to a substrate, and a binder such as polyamide imide resin, is dispersed in various solvents to prepare slurry-state lubricating compositions, and the lubricating compositions are applied to the front and sides of a swash plate made of an iron- or aluminum-based material to form lubricating layers. The lubricating properties of such lubricating compositions comprising a binder resin, a solid lubricant, additives and a solvent significantly differ depending on the surface state of a swash plate, the physical properties of the lubricating composition, and conditions in which the lubricating composition is coated on the surfaces of the swash plate. Japanese Unexamined Patent Application Publication No. 2009-209727 discloses that both surfaces of a disc-shaped steel plate are polished, and a low-friction resin coating layer comprising 40-50 wt % of fluorine resin (PTFE, etc.), 1-10 wt % of graphite and 45-55 wt % of matrix resin is formed on a sliding surface of the polished steel plate, which slides against shoes. Korean Patent No. 10-1086847 discloses a lubricating member comprising 30-70 wt % of a binder, 25-60 wt % of a solid lubricant and 5-10 wt % of other additives. However, the patent document discloses only the ratio of components in the lubricating member, does not mention a liquid slurry composition for the lubricating member composition, and thus does not disclose the contents of solids (binder, solid lubricant, other additives, etc.) in a lubricating member slurry for coating on a sliding member, the kind of solvent, and the viscosity of a liquid lubricating coating composition. However, in an actual operation of coating the lubricating member on the surface of a swash plate, the ratio of the solid lubricant in the composition, the kind of solvent, and the changes in solid content and viscosity by the addition of the solvent, will influence the various physical and chemical properties of the lubricating member, including abrasion resistance, adhesion to a substrate, heat resistance, durability, seizure resistance and lubricating properties. In fact, if the amount of a solvent in a lubricating composition is too large, it will be difficult to form a uniform and thin coating layer even by any coating process, and if the viscosity of a lubricating composition is too low, it will be difficult to form a coating layer having a desired thickness, because the adhesion of the composition to a substrate is low.