In view of the importance of the sealing performance, elastic bodies (e.g. rubber) are used for parts that slide while maintaining the sealing performance, such as a gasket which is integrated with a plunger of a syringe and forms a seal between the plunger and the barrel. Such elastic bodies, however, have a slight problem in their sliding properties (see Patent Literature 1). Thus, a sliding property improving agent (e.g. silicone oil) is applied to the sliding surface. It is, however, pointed out that silicone oil may have a negative influence on recently marketed bio-preparations. Meanwhile, gaskets to which no sliding property improving agent is applied are poor in the sliding properties. Thus, such a gasket does not allow the plunger to be pushed smoothly but causes it to pulsate during administration. Hence, some problems occur, such as inaccuracy in the injection amount and pain for patients.
A technique of applying a self-lubricating PTFE film is proposed to simultaneously satisfy these conflicting requirements, that is, the sealing properties and the sliding properties (see Patent Literature 2). The film, however, is generally expensive and thus increases the production cost of processed products, limiting its application range. Moreover, reliability concerns exist with the use of PTFE film-coated products in applications where durability against repeated sliding motion is required. Another problem is that as PTFE film are vulnerable to radiation, PTFE film-coated products cannot be sterilized by radiation.
Furthermore, the use in other applications where sliding properties in the presence of water are required can be considered. Specifically, water can be delivered without a loss by reducing the fluid resistance of the inner surface of a pre-filled syringe or of the inner surface of a pipe or tube for delivering water, or by increasing or greatly reducing the contact angle with water. Moreover, drainage of water on wet roads and of snow on snowy roads can be improved by reducing the fluid resistance of the groove surfaces of tires, or by increasing or greatly reducing the contact angle with water. This leads to enhanced hydroplaning performance and grip performance, and therefore better safety. In addition, less sticking of wastes and dusts can be expected by reducing the sliding resistance of the sidewall surfaces of tires or walls of buildings, or by increasing their contact angle with water.
Further advantageous effects can be expected, such as: less pressure loss in delivering water, an aqueous solution or the like through a diaphragm such as diaphragm pumps or valves; easy sliding of skis or snowboards achieved by enhancing the sliding properties of the sliding surfaces thereof; better noticeability of road signs or signboards achieved by enhancing the sliding properties thereof to allow snow to slide easily on the surface; reduction in water drag and thus less sticking of bacteria to the outer peripheries of ships, achieved by reducing the sliding resistance of the outer peripheries or by increasing the contact angle with water; and reduction in water drag of swimsuits by improving the sliding properties of the thread surfaces thereof.