JP2005239739A - Dimethyl ether-resistant polymer member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer member which exhibits resistance to DME and LPG, can be commonly used for DME and LPG, and maintains excellent sealing performances. <P>SOLUTION: The dimethyl ether-resistant polymer member arranged at places brought into contact with dimethyl ether gas or liquid comprises a rubber member which is impregnated with a lubricating oil having a bivalent perfluoroether structure in the main chain or with a grease comprising the lubricating oil as a base oil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is applied to an apparatus / apparatus that comes into contact with gaseous or liquid DME at the stage of manufacturing, storing, transporting, supplying, and using dimethyl ether (hereinafter abbreviated as “DME”), and further, the apparatus for LPG The present invention relates to a polymer member that can be shared with other devices.

  Rubber members such as O-rings and seals that are widely used in various industrial devices and equipment are coated with a lubricant for the purpose of improving the familiarity with the joint surface and improving the sealing performance or durability. There are many cases. A rubber member impregnated with a lubricant is also used. In the LPG industry, rubber-based seal members are used in pipe connection parts and valves, etc. in supply facilities such as primary bases, secondary bases, filling stations, and transportation facilities such as ocean-going vessels, coastal ships, and tank trucks. For the same purpose, lubricating oil such as mineral oil or synthetic oil, or grease based on these lubricating oils is applied and impregnated (for example, see Patent Document 1).

  On the other hand, LPG relies on imports for about 80% of supply, and about 80% for imports in the Middle East. In recent years, Asian countries such as China and India have diversified as income levels rise. The demand for LPG as a type fuel is increasing rapidly, and there is a problem that high price stability is becoming constant due to tight supply and demand. In response to this situation, there is an active movement to find new energy sources, and LNG and GTL are attracting attention as LPG alternative fuels, but LNG and GTL are other alternative fuels, especially DME. In comparison, there is a problem that the construction cost of the plant is high.

Among other alternative fuels, DME has a chemical structure of CH ₃ OCH ₃ and usually uses DME as a raw material from synthesis gas (CO ₂ , H ₂ ) obtained by gasifying natural gas, associated gas, coal, etc. It is obtained by synthesis and does not generate soot and SOx when burned, and has a clean feature of low NOx, so its use as a fuel for power generation, boilers, households, automobiles, etc. is being studied. . Moreover, since this DME is similar to LPG in physical properties such as vapor pressure, it is considered possible to utilize the infrastructure of LPG. In recent years, DME is being used as an alternative fuel for LPG. The movement is increasing.

  However, DME is chemically classified as ether, and its chemical properties are completely different from LPG consisting of propane and butane, which are paraffinic hydrocarbons, and has high gas permeability to organic compounds such as plastic and rubber. It has the feature that it is easy to swell and dissolve. Therefore, in the rubber member used for the conventional LPG, the lubricant applied or impregnated, and further, the rubber member itself is easily extracted in contact with the DME, so that the function can be sufficiently performed. There are concerns that cannot be made.

Japanese Patent Laid-Open No. 10-274336

  In this way, DME is attracting attention as a promising candidate as an alternative fuel for LPG, and in order to be able to use the infrastructure of LPG as it is, development of a material highly resistant to DME is urgently required. . Therefore, an object of the present invention is to provide a polymer member that has resistance to DME and LPG, can be shared for DME, and further for LPG and can maintain excellent sealing performance.

  As a result of repeated investigations to solve the above problems, the present inventors have found that specific fluorine-based lubrication exhibits DME resistance and LPG resistance, and have completed the present invention.

  That is, in order to achieve the above object, the present invention provides a rubber member disposed at a position in contact with a dimethyl ether gas or liquid, the lubricating oil having a divalent perfluoropolyether structure in the main chain, Provided is a dimethyl ether-resistant polymer member, which is impregnated with grease based on a lubricating oil.

  ADVANTAGE OF THE INVENTION According to this invention, the sealing performance of the apparatus and apparatus which contacts DME and also LPG can be maintained favorable.

  Hereinafter, the present invention will be described in detail.

  In the DME resistant rubber member of the present invention, the rubber material forming the rubber member is not limited, and acrylic rubber, fluorine rubber, silicon rubber and the like that have been widely used can be used. It is preferable to use a rubber having resistance to LPG. Examples of such rubber include acrylonitrile butadiene rubber, hydrogenated acrylonitrile butadiene rubber, PTFE, PFA, nylon, polyethylene, polyester, etc. containing 38% by weight or more of acrylonitrile previously filed by the present applicant (Japanese Patent Application No. 2002-304358). A rubber composition as a base rubber can be given as a preferred example.

The rubber material is molded into a predetermined shape such as a ring shape, a sheet shape, or a tape shape, and impregnated with a lubricating oil having a divalent perfluoropolyether structure in the main chain or a grease based on the lubricating oil. Examples of such lubricating oil include, but are not limited to, those represented by the following general formula (1). In addition, n is 5-100, Preferably it is 15-50.
F (C ₃ F ₆ O) _n C ₂ F ₅ (1)

  Further, there is no limitation on the thickener for making grease, but PTFE, metal soap (Li, Ca, Na, Al), organic matter (diurea, tetraurea compound), organic bentonite, carbon black, inorganic filler, silica gel, Graphite, sodium terephthalate, etc. are suitable. As such grease, for example, those sold under the trade name “Molicoat HP Grease” from Dow Corning Asia Co., Ltd. or “Demnam Grease” from Daikin Industries, Ltd. can be used.

  The method for producing the DME-resistant polymer member of the present invention is not limited, but a method of immersing and drying a rubber material molded into a predetermined shape in the lubricating oil or grease is simple and efficient.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to the following Example.

(Examples 1-5, Comparative Examples 1-5)
A PTFE rubber sheet was impregnated with a certain amount of grease shown in Table 1 to obtain a test specimen.

  The specimen was immersed in DME by a method according to JIS K 6258, the weight before and after immersion was measured, and the difference in grease extraction by DME was evaluated. The test results are shown in Table 2.

  As can be seen from Table 2, the test specimens of each example using a grease based on a lubricating oil having a divalent perfluoropolyether structure in the main chain in accordance with the present invention have almost no extraction by DME, and are resistant to DME. Excellent in properties.

Claims (1)

  A polymer member disposed at a position in contact with dimethyl ether gas or liquid, the main chain is impregnated with a lubricating oil having a divalent perfluoropolyether structure or a grease based on the lubricating oil. A dimethyl ether resistant polymer member characterized by the above.