JP5244469B2 - Method for imparting DME resistance to rubber components - Google Patents

Description

The present invention relates to the DME-resistant method imparting rubber component. More specifically, the present invention relates to a rubber composition and the like suitable for forming a sealing material that comes into contact with gaseous or liquid DME at the stage of manufacturing, storing, transporting, supplying, and using DME.

Dimethyl ether (DME) has a chemical structure of CH ₃ OCH ₃ and has physical properties similar to those of LPG. DME is a gas body at normal temperature and normal pressure, but easily liquefies by either pressurization or low temperature.

DME is obtained by DME synthesis using synthetic gas (CO ₂ , H ₂ ) obtained by gasifying natural gas, associated gas, coal, or the like as a raw material.

  DME is attracting attention as a next-generation fuel that does not generate soot and SOx when burned, has low NOx, and is clean and environmentally friendly.

  In recent years, there has been a movement to use such DME as an alternative fuel for light oil and LPG, and its use as a fuel for power generation, boilers, homes, automobiles, and the like has been studied.

  When DME is used as fuel or the like, rubber components such as NBR and fluororubber are used as a sealing material for fuel storage tanks and pipes, but these rubber components have a relatively low resistance to DME.

  That is, DME is chemically classified as ether, and its chemical properties are completely different from those of LPG made of propane and butane, which are paraffinic hydrocarbons. It has the feature of being easily generated.

  The swelling phenomenon of rubber by DME occurs when DME enters the rubber composition in such a manner as to push away the plasticizer component and the like contained in the rubber composition. When DME enters the rubber composition, the volume of the rubber composition itself increases.

  Therefore, when used as, for example, an O-ring packing formed of a rubber composition in the presence of DME, the O-ring swells and the slidability of the movable portion of the packing is significantly reduced. Thereby, operation, such as a stopper, may become difficult.

  The rubber extraction phenomenon by DME occurs when DME that has entered the rubber composition due to the swelling phenomenon of the rubber composition is released to the outside of the rubber composition. That is, even when DME is released to the outside of the rubber composition, the plasticizer component pushed out of the rubber composition during the swelling phenomenon cannot enter the inside of the rubber composition again, and the volume of the rubber composition itself is Decrease from the beginning.

  Therefore, if the O-ring swells in the presence of DME and then DME is released to the outside of the rubber composition, there is a possibility that a gap will be left in the mounting portion sealed with the O-ring, thereby causing leakage of gas or the like There is.

  Therefore, development of a rubber composition having high resistance to DME (DME resistance) is demanded while DME is attracting attention as a promising candidate as a fuel.

  In Patent Document 1, an attempt is made to impart resistance to DME to a rubber component by using a rubber composition in which the acrylonitrile content of the nitrile rubber is increased.

However, the rubber composition in the technique described in Patent Document 1 does not have a DME resistance that can be used as a packing in the presence of actual DME.
JP 2004-137391 A

The present invention has been made in view of such problems, and an object thereof is to provide an effective resistance to DME imparting methods novel against rubber component.

To achieve the above Symbol purpose, the DME-resistant method imparting a rubber component according to the inventions are
The rubber component used in the sealing material contains a swelling suppression lubricant that suppresses swelling of the rubber component with dimethyl ether (DME) and imparts lubricity to the rubber component. powder, it contains at least one of silicone powder, polytetrafluoroethylene powder, and wherein the.

  The rubber component may contain at least one of hydrogenated nitrile rubber (HNBR), nitrile rubber (NBR), and ethylene-propylene-diene rubber (EPDM).

  Moreover, it is also possible that content of the said swelling suppression lubricant is 10 to 50 weight part with respect to 100 weight part of said rubber components.

  Further, it is possible to contain at least one of carbon black, silica, and clay as a filler.

  The rubber composition according to the present invention is a novel rubber composition having excellent resistance to DME.

[Method of imparting DME resistance of rubber composition / rubber component]
The rubber composition according to the present embodiment has a rubber component and a swelling suppression lubricant. Moreover, the method for imparting DME resistance of the rubber component according to the present embodiment includes a rubber component used for the sealing material containing a swelling suppression lubricant.

Even if the rubber composition is filled with an additive having only an effect of suppressing swelling due to DME, if the rubber composition is molded into a sealing material, the slidability is poor and the function as a sealing material is insufficient. There is a risk of becoming.
Therefore, in the present invention, the rubber composition contains a swelling-suppressing lubricant, which is a member that suppresses swelling of the rubber composition due to DME and imparts lubricity to the rubber composition.

As the swelling-suppressing lubricant, polyethylene powder, silicone powder, polytetrafluoroethylene powder, or the like, or a mixture thereof can be used.
Furthermore, nylon powder, polymethylmethacrylate powder, polyurethane powder, polystyrene powder, polyester powder, microsponge, methyl sesquioxane resin microbeads, and the like can also be used as the swelling suppression lubricant.

  The polyethylene powder is not particularly limited as long as it is a low-density, medium-density or high-density polyethylene as long as it is obtained by processing polyethylene into a powder form.

  The polyethylene powder preferably has an average molecular weight of 30,000 or more, more preferably 1,000,000 or more. This is because if the average molecular weight is less than 30,000, the wear resistance may not be improved.

  The average particle size of the polyethylene powder is preferably 1 μm to 600 μm, and more preferably 20 μm to 300 μm. This is because if the average particle size is smaller than 1 μm, the dispersibility in the rubber composition may be lowered. On the other hand, when the average particle size is larger than 600 μm, there is a possibility that poor appearance when formed into an O-ring or the like as described later may occur.

  As specific polyethylene powders, for example, MIPELLON XM-220 and MIPELON XM-221U manufactured by Mitsui Chemicals, Inc., Sunfine LH411 manufactured by Asahi Kasei Co., Ltd., and the like can be used.

  As the silicone powder, any of silicone resin powder, silicone rubber powder, or silicone composite powder which is spherical powder obtained by coating the surface of spherical silicone rubber powder with silicone resin can be preferably used.

  The hardness of the silicone powder can be, for example, a Duro A hardness of 20 to 80, preferably 35 to 55. This is because if the resin hardness is in the range of 20 to 80, it is effective for reducing the elastic modulus of the rubber composition and there is little decrease in strength.

  The shape of the silicone powder is preferably spherical or substantially spherical.

  The average particle size of the silicone powder can be, for example, 0.1 to 500 μm, and preferably 1 to 200 μm. This is because if the average particle size is smaller than 0.1 μm, the dispersibility in the rubber composition may be lowered. On the other hand, if the average particle size is larger than 500 μm, there may be a risk of appearance failure when molding.

  Specific examples of the silicone resin powder include Tospearl 120, Tospearl 120A, Tospearl 130, Tospearl 145, Tospearl 145A, Tospearl 2000B *, Tospearl 2000B, Tospearl 240 *, and Tospearl 3120 manufactured by GE Toshiba Silicone. be able to. For example, KMP-590, KMP-701, X-52-854, etc. of Shin-Etsu Chemical Co., Ltd. can be used.

  Moreover, as specific silicone rubber powder, Shin-Etsu Chemical Co., Ltd. KMP-597, KMP-598, KMP-594, X-52-875 etc. can be used, for example.

  As specific silicone composite powders, for example, KMP-600, KMP-601, KMP-602, KMP-605, X-52-7030, etc., manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

  The polytetrafluoroethylene powder is not particularly limited as long as it is a polytetrafluoroethylene (PTFE) processed into a powder form.

  The average molecular weight of the polytetrafluoroethylene powder is preferably 50,000 to 10,000,000. This is because when the average molecular weight is larger than 10 million, the dispersibility of the polytetrafluoroethylene powder in the rubber composition may be lowered. On the other hand, if the average molecular weight is less than 50,000, the slidability may not be improved.

  The average particle diameter of the polytetrafluoroethylene powder can be, for example, 1 μm to 200 μm, and preferably 10 to 100 μm. This is because if the average particle size is smaller than 1 μm, the dispersibility in the rubber composition may be lowered. On the other hand, when the average particle size is larger than 200 μm, there is a possibility that appearance defects may occur when molding is performed.

  As specific polytetrafluoroethylene powder, for example, Fluon (registered trademark) G190 series manufactured by Asahi Glass Co., Ltd., New Polyflon M-111, Lubron L-2 manufactured by Daikin Industries, Ltd., etc. should be used. Can do.

  As the rubber component, hydrogenated nitrile rubber (HNBR), nitrile rubber (NBR), ethylene-propylene-diene rubber (EPDM), or the like can be used.

  Nitrile rubber (NBR) has low nitrile content (content 24% or less), medium nitrile (content 25% to 30%), medium to high nitrile (content 31% to 35%), high nitrile (content Any of 36% to 42%) and extremely high nitrile (content 43% or more) can be preferably used.

  Hydrogenated nitrile rubber (HNBR) is hydrogenated conjugated diene unit part of nitrile-conjugated diene copolymer rubber, hydrogenated conjugated diene unit part of nitrile-conjugated diene-ethylenically unsaturated monomer terpolymer rubber. Nitrile-ethylenically unsaturated monomer copolymer rubber or the like can be used, but is not limited thereto.

  Ethylene-propylene-diene rubber (EPDM) is a third component introduced into the ethylene-propylene chain. Ethylidene norbornene (ENB), 1,4-hexadiene (1,4-HD), dicyclopentadiene (DCP) Etc. can be used.

  The content of the above-described swelling suppression lubricant can be 10 to 50 parts by weight with respect to 100 parts by weight of the rubber component. This is because if the content of the swelling suppression lubricant is less than 10 parts by weight, the volume change rate of the rubber composition after dipping in DME may be increased. On the other hand, when the content of the swelling suppression lubricant is more than 50 parts by weight, the molding processability may be deteriorated because the content ratio of the rubber composition itself is relatively small. In addition, even if the molding processability is slightly deteriorated by containing more than 50 parts by weight of the swelling suppression lubricant, it is a problem of the molding processing means, and the swelling suppression lubricant cannot be contained by 50 parts by weight or more. is not.

  Moreover, the rubber composition according to the present embodiment can contain a filler. As the filler, carbon black, silica, clay and the like can be suitably used.

  As carbon black, furnace black, thermal black, channel black, etc. can be used.

  Inorganic fillers other than silica and clay include metal powders such as aluminum, copper, iron, lead, nickel, silver, diatomaceous earth, alumina, titanium oxide, calcium oxide, magnesium oxide, zinc oxide, iron oxide, oxidation Oxides such as beryllium, hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, aluminate hydrate, silicates such as talc, mica, asbestos, bentonite, zeviolite, calcium silicate, montmorillonite , Carbonates such as calcium carbonate, magnesium carbonate and hydrotalcite, sulfates such as calcium sulfate sulfate, calcium sulfite sulfate, barium sulfate and calcium sulfite can be used, and molybdenum disulfide, titanium Potassium acid, silicon carbide and the like can also be used as inorganic fillers.

  Furthermore, organic fillers can also be used as the filler. For example, linter, linen, sisal wood flour, silk, leather powder, collagen fiber, viscose, acetate, etc. can be used. .

  In addition, the rubber composition according to the present embodiment includes a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerator, a vulcanization retarder, etc. in a predetermined blending amount in addition to the rubber component and the swelling-suppressing lubricant. It can be included. As the vulcanizing agent, for example, in addition to sulfur-based vulcanizing agents such as sulfur, sulfur dichloride, morpholine disulfide, non-sulfur vulcanizing agents such as organic peroxides and metal oxides can be used. As the vulcanization accelerator, for example, thiuram, thiazole, sulfenamide, sulfide, and thiourea compounds can be used. As a vulcanization retarder, for example, salicylic acid or the like can be used.

  Furthermore, the rubber composition according to the present embodiment may contain various additives such as a plasticizer, an antioxidant, a softening agent, a tackifier, and an anti-aging agent for the purpose of improving the quality. Specific examples of the plasticizer include synthetic plasticizers such as phthalic acid ester, diallyl phthalate, adipic acid ester, fatty acid ester, trimellitic acid ester, and the like. Examples of the antioxidant include diphenylamine-based antioxidants such as dioctylated diphenylamine, and p-phenylenediamine-based antioxidants such as N, N′-diphenyl-p-phenylenediamine. As the softener, for example, fatty acid, tall oil and the like can be used. The anti-aging agent is not particularly limited as long as it is a heat-resistant anti-aging agent, a weather-resistant anti-aging agent and the like which are usually used in rubber compositions. Specific examples thereof include N- (1,3-dimethylbutyl). ) -N'-phenyl-p-phenylenediamine (6PPD), N, N'-dinaphthyl-p-phenylenediamine (DNPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), styrenated phenol (SP) etc. are mentioned.

The rubber composition according to this embodiment is produced by the following method.
That is, first, for example, 10 to 50 parts by weight of a swelling suppression lubricant such as polyethylene powder is contained per 100 parts by weight of a rubber component such as HNBR, and a vulcanizing agent such as sulfur or a thiuram vulcanization accelerator is added. It is made to contain and the rubber composition which is not vulcanized is obtained.

  The rubber composition is primarily vulcanized at a predetermined temperature of, for example, about 130 ° C. to 200 ° C., for example, for 10 to 20 minutes, and then at a predetermined temperature of, for example, about 140 ° C. to 180 ° C. It can be obtained by secondary vulcanization for a period of time.

[DME resistant rubber composition]
The rubber composition for DME resistant according to the present embodiment is a rubber composition that has DME resistance and is used in an environment where it is used in an environment where it is in contact with gas or liquid DME.

  The DME-resistant rubber composition has a rubber component and an additive.

  As the rubber component, hydrogenated nitrile rubber (HNBR), nitrile rubber (NBR), ethylene-propylene-diene rubber (EPDM) or the like can be used as described above.

  As the additive, the above-described polyethylene powder, silicone powder, polytetrafluoroethylene powder, and the like can be used.

  The rubber composition for DME-resistant rubber can contain the above-mentioned filler, a predetermined amount of vulcanizing agent, a vulcanization accelerator, a vulcanization acceleration aid, a vulcanization retarder, and the like. .

[Sealant]
The sealing material according to the present embodiment is molded using the rubber composition according to the present embodiment as its material.

  The sealing material can be processed into an O-ring 900 as shown in FIG. A vertical pipe 400 is connected to one end of the horizontal pipe 100. An O-ring groove that is recessed along the circumferential direction of the inner surface of the pipe is formed at the upper end of the vertical pipe 400. An O-ring 900 is fitted in the O-ring groove. A plug 200 made of metal or the like is fitted into the vertical pipe 400 so as to be in contact with the O-ring 900. A handle 300 is provided on the top of the stopper 200.

  Even if liquid or gaseous DME flows from the other end of the horizontal pipe 100 and flows in the vicinity of the stopper 200 as shown by an arrow in FIG. It is formed with the rubber composition concerning. For this reason, not only is the sealing performance of the O-ring 900 difficult to deteriorate due to the swelling / extraction phenomenon of DME, but smooth opening and the like are possible due to the improved slidability.

  The shape of the O-ring 900 is not limited to a solid round shape as shown in FIG. 1, and various shapes are possible. An annular shape having holes may be used.

  Further, the place where the O-ring 900 is installed is not limited to that shown in FIG. 1, and can be installed on the outer peripheral surface near the end of the pipe, for example.

  Furthermore, the specific shape of the sealing material formed by processing the rubber composition according to the present embodiment is not limited to the O-ring, and examples thereof include V packing, U packing, cup packing, and flange packing. Various shapes are possible.

Example 1
100 parts by weight of HNBR (manufactured by ZEON Corporation, Zetpol 0020) as a rubber component, 10 parts by weight of polyethylene powder (Mipelon XM-220, manufactured by Mitsui Chemicals, Inc.) as an anti-swelling lubricant, and organic peroxide as a vulcanizing agent A rubber composition containing 5 parts by weight of the rubber composition was subjected to primary vulcanization at 170 ° C. for 10 minutes, then secondary vulcanization at 150 ° C. for 2 hours, and then molded to prepare a test piece of the rubber composition.

(Example 2)
A rubber composition test piece was prepared in the same manner as in Example 1 except that 50 parts by weight of polyethylene powder as a swelling-suppressing lubricant was contained.

(Example 3)
A test piece of a rubber composition was prepared in the same manner as in Example 1 except that 150 parts by weight of polyethylene powder as a swelling suppression lubricant was contained.

(Comparative example)
A test piece of a rubber composition was prepared in the same manner as in Example 1 except that polyethylene powder as a swelling suppression lubricant was not included.

  For the test piece of rubber composition thus prepared, compression set (%), volume change rate after immersion in DME (%), dynamic friction coefficient, strength at break (MPa), elongation at break (% ) And hardness (Duro A hardness).

  The compression set (%) is used to test the sealability of the rubber composition and was tested according to JIS K6262. A large-diameter test piece was used as the shape of the test piece. That is, the diameter was 290 ± 0.5 mm and the thickness was 12.5 ± 0.5 mm. Since the hardness of the test piece was 10 to 79 in IRHD, 25% was selected as the ratio for compressing the test piece. The test time was 72 hours.

In the standard state of the test chamber, insert the test piece into the center between the compression plates of the compression device and the specified spacer outside the test piece, and then compress until the compression plate is in close contact with the spacer. Tightened and fixed in that state.
After compressing the test piece, the compression apparatus was immediately put into a thermostatic chamber adjusted to the test temperature in advance. This time was taken as the test start time and heated at 100 ± 1 ° C.
After completion of the heat treatment, the compression device is taken out from the thermostatic chamber, the test piece is quickly removed from the compression device, placed on the table, and left in the standard state of the test room for 30 ± 3 minutes, and then the thickness of the central part of the test piece is measured. The measurement was performed by the formula (1).

Here, Cs is compression set (%), t ₀ is the original thickness (mm) of the test piece, t ₁ is the thickness (mm) of the spacer, and t ₂ is the test piece. The thickness (mm) after 30 minutes from removal from the compression apparatus.

  The compression set of Example 1 is 30%, the compression set of Example 2 is 40%, the compression set of Example 3 is 61%, and the compression set of Comparative Example is 25%. there were.

  Next, the coefficient of dynamic friction is used to test the slidability of the rubber composition and was tested according to JIS K6264. The measurement was performed under a load of 10 kgf / cm 2, a speed of 60 m / min, and a distance of 10 mm using an Orientec Suzuki-Matsubara friction and wear tester.

  The dynamic friction coefficient of Example 1 was 0.84, the dynamic friction coefficient of Example 2 was 0.83, the dynamic friction coefficient of Example 3 was 0.98, and the dynamic friction coefficient of the comparative example was 0.83.

Next, the volume change rate after immersion in DME was measured according to JIS K6258.
Three test pieces of 20 mm × 50 mm × 2 mm thickness were put into a pressure vessel, and liquefied DME was injected.
And it was left to stand at 40 degreeC for 24 hours. Thereafter, DME was removed, and the test piece was quickly taken out and placed in a desiccator. The test piece was taken out from the desiccator, and the volume change rate after 12 minutes was calculated by the formula (2).

  Here, Va is the volume after immersion, Vb is the volume before immersion, and Vc is the volume change rate.

  The volume change rate of Example 1 was 30%, the volume change rate of Example 2 was 30%, the volume change rate of Example 3 was 22%, and the volume change rate of the comparative example was 39%.

Next, the strength at break (MPa) was tested according to JIS K6251.
The breaking strength of Example 1 is 15.4 MPa, the breaking strength of Example 2 is 16.9 MPa, the breaking strength of Example 3 is 14.3 MPa, and the breaking strength of the comparative example is 18.4 MPa. there were.

Next, the elongation at break (%) was tested in accordance with JIS K6251.
The elongation at break of Example 1 was 400%, the elongation at break of Example 2 was 390%, the elongation at break of Example 3 was 240%, and the elongation at break of the Comparative Example was 400%.

Next, the hardness (Duro A) was tested according to JIS K6253.
The hardness of Example 1 was 90, the hardness of Example 2 was 91, the hardness of Example 3 was 97, and the hardness of the comparative example was 84.

  The results of these tests are shown in Table 1 below.

  Regarding the dynamic friction coefficient, in Examples 1 to 3, good results were obtained. In particular, it can be seen that Example 1 and Example 2 have a lower coefficient of dynamic friction than Example 3, and are particularly excellent in slidability when molded into a sealing material.

  Regarding the compression set, in Examples 1 to 3, good results were obtained. In particular, it can be seen that Example 1 and Example 2 have a lower compression set than Example 3 and are particularly excellent in sealing properties when molded into a sealing material.

  Regarding the volume change rate after immersion in DME, the comparative example had a large volume change rate of 39%. However, Example 1 is 30%, Example 2 is 30%, and Example 3 is 22%, both of which are good values. Examples 1 to 3 have DME resistance unlike the comparative examples. I found out.

  Therefore, in the case of a rubber composition containing polyethylene powder as a swelling-suppressing lubricant in a rubber component, such a sealing material is excellent in slidability even if molded into a sealing material such as an O-ring. It is understood that it exhibits excellent physical properties such as excellent DME resistance as well as excellent properties.

Example 4
100 parts by weight of HNBR (manufactured by Nippon Zeon Co., Ltd., Zetpol 0020) as a rubber component, 10 parts by weight of silicone powder (manufactured by Momentive Performance Materials, Tospearl 2000B) as a swelling-suppressing lubricant, and organic excess as a vulcanizing agent A rubber composition containing 5 parts by weight of oxide was subjected to primary vulcanization at 170 ° C. for 10 minutes, then secondary vulcanization at 150 ° C. for 2 hours, and then molded to prepare a test piece of the rubber composition.

(Example 5)
A rubber composition test piece was prepared in the same manner as in Example 4 except that 50 parts by weight of silicone powder as a swelling-suppressing lubricant was contained.

  For the test piece of rubber composition thus prepared, compression set (%), volume change rate after immersion in DME (%), dynamic friction coefficient, strength at break (MPa), elongation at break (% ), Hardness (duro A hardness), and the same method as described above.

  The compression set of Example 4 was 28%, and the compression set of Example 5 was 30%.

  The volume change rate of Example 4 was 32%, and the volume change rate of Example 5 was 32%.

  The dynamic friction coefficient of Example 4 was 0.82, and the dynamic friction coefficient of Example 5 was 0.73.

  The breaking strength of Example 4 was 14.9 MPa, and the breaking strength of Example 5 was 13.7 MPa.

  The elongation at break of Example 4 was 360%, and the elongation at break of Example 5 was 350%.

  The hardness of Example 4 was 89, and the hardness of Example 5 was 90.

  The results of these tests are shown in Table 2 below.

  Regarding the dynamic friction coefficient, in Example 4 and Example 5, it was a favorable result. Also, the compression set was a good result in Example 4 and Example 5.

  Regarding the volume change rate after DME immersion, although the comparative example was 39%, Example 4 and Example 5 were good values of 32% and Example 5 were 32%. Example 5 was found to have DME resistance unlike the comparative example.

  Therefore, in the case of a rubber composition containing a rubber component containing silicone powder as a swelling-suppressing lubricant, even if it is molded into a sealing material such as an O-ring, such a sealing material is excellent in slidability and seal. It is understood that it exhibits excellent physical properties such as excellent DME resistance as well as excellent properties.

  As described above, rubber compositions containing polyethylene powder or silicone powder as a swelling-suppressing lubricant in rubber components such as HNBR are excellent in slidability, excellent in DME resistance, and molded into sealing materials such as O-rings. It has been found that even if processed, it has excellent sealing properties. When polytetrafluoroethylene powder is contained as a swelling-suppressing lubricant, it is similarly excellent in slidability, excellent in DME resistance, and excellent in sealing properties even when molded into a sealing material such as an O-ring.

It is a figure explaining the usage pattern of the sealing material which concerns on this embodiment.

Explanation of symbols

100 Horizontal piping 200 Plug 300 Handle 400 Vertical piping 900 O-ring

Claims (4)

The rubber component used for the sealing material contains a swelling-suppressing lubricant that suppresses swelling of the rubber component by dimethyl ether (DME) and imparts lubricity to the rubber component .
The swelling-controlled lubricant is polyethylene powder, you contain at least one of silicone powder, polytetrafluoroethylene powder,
A method for imparting DME resistance to a rubber component. The rubber component contains at least one of hydrogenated nitrile rubber (HNBR), nitrile rubber (NBR), and ethylene-propylene-diene rubber (EPDM).
The method for imparting DME resistance to a rubber component according to claim 1 . The content of the swelling suppression lubricant is 10 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the rubber component.
The method for imparting DME resistance to a rubber component according to claim 1 or 2 . As a filler, it contains at least one of carbon black, silica, clay,
The method for imparting DME resistance of a rubber component according to any one of claims 1 to 3 , wherein:

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