JP2015174927A - Foam and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam using a fluorine-based rubber consisting of a copolymer of tetrafluoroethylene excellent in heat and oil resistances and also in chemical resistance and a perfluoroalkyl vinyl ether and its production method.SOLUTION: A foam uses a fluorine-based rubber consisting of a copolymer of tetrafluoroethylene and a perfluoroalkyl vinyl ether, has a specific gravity of 0.1-0.5 and includes cells of an average cell diameter of 100 μm or smaller.

Description

  The present invention is widely used in the fields of semiconductor manufacturing processes, automobile parts manufacturing processes, personal computer and mobile device manufacturing processes, OA (Office Automation) devices such as copiers and printers, and the like. The present invention relates to a foam using a fluorine rubber excellent in oil resistance and the like and a method for producing the same.

  Conventional rubber foams having excellent heat resistance include silicone rubber foams and fluorine rubber foams. Fluorine-based rubber foams are excellent in heat resistance and chemical resistance, and are therefore used as sealing materials for chemical containers and as part sealing materials in semiconductor manufacturing processes.

  Conventionally, the fluorine-based rubber used for the fluorine-based rubber foam is a binary fluorine-based rubber obtained by copolymerizing vinylidene fluoride (VDF) and hexafluoropropylene (HEP), and further tetrafluoro. A ternary fluorine-based rubber (FKM) copolymerized with ethylene (TFE; Tetrafluoroethylene) is used (see Patent Document 1). A conventional method for producing a fluorinated rubber foam is also proposed in Patent Document 2.

JP 07-278335 A JP 2005-146030 A

  However, the conventional foams using fluororubbers mainly use vinylidene fluoride rubbers as fluororubbers. Compared to other rubber foams, the foams are heat and oil resistant. Although the property is excellent, regarding chemical resistance, especially when used as an application of an O-ring or a gasket, the life is short and further improvement is desired.

  The inventors of the present invention have further improved the chemical resistance of foams using conventional fluororubbers, and have advanced research on foams using fluororubbers with plasma resistance. As a result, tetrafluoroethylene and The present inventors have succeeded in obtaining a foam using a fluorine rubber made of a copolymer with perfluoroalkyl vinyl ether.

  This invention solves the said subject, The place made into the objective provides the foam which was excellent also in chemical resistance in addition to heat resistance and oil resistance, and its manufacturing method.

  In order to achieve the above object, a foam according to the present invention is a foam using a fluorine-based rubber composed of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, and has a specific gravity of 0.1 to 0. In the range of 0.5, the average bubble diameter is 100 μm or less.

  The method for producing a foam according to the present invention is a method for producing the foam, in which a pyrolytic foaming agent 0 is added to 100 parts by weight of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether. .5 parts by weight to 10 parts by weight and 0.1 to 5 parts by weight of a peroxide-based crosslinking agent.

  The foam according to the present invention is excellent in chemical resistance and plasma resistance in addition to heat resistance and oil resistance.

It is a figure which shows the immersion test result of the foam which concerns on this invention.

  An embodiment of a foam and a method for producing the same according to the present invention will be specifically described with reference to the drawings.

  The foam of this embodiment is a foam using a fluorine-based rubber made of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, and the specific gravity is within the range of 0.1 to 0.5. It has bubbles with an average bubble diameter of 100 μm or less. As a method for producing the foam, 0.5 parts by weight to 10 parts by weight of a pyrolytic foaming agent and a peroxide-based crosslinking agent with respect to 100 parts by weight of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether It is produced by blending 0.1 to 5 parts by weight.

  As the pyrolytic foaming agent used in the present embodiment, azodicarbonamide is preferable. Furthermore, hydrazosicarbonamide, azodicarboxylic acid barium salt, dinitrosopentaethylenetetramine, nitrosoguanidine, p, p'-oxybisbenzenesulfonyl semicarbazide, trihydrazinecin having a decomposition temperature equivalent to or higher than azodicarbonamide Metric triazine, bisbenzenesulfonyl hydrazide, barium azodicarbaxylate, azobisisobutyronitrile, toluenesulfonyl hydrazide and the like are used. These may be used alone or in combination of two or more.

  The compounding amount of the pyrolytic foaming agent is such that the pyrolytic foaming agent is used with respect to 100 parts by mass of the fluororubber composed of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether in the fluororubber composition. It is about 0.5 to 10 parts by mass, and is set according to the desired expansion ratio.

  Peroxide-based crosslinking agents used in this embodiment include dicumyl peroxide, 2,5-dimethyl-2,5-bis-tert-butylperoxyhexane, 1,3-bis-tertiary peroxy-isopropylbenzene. An organic peroxide such as can be used.

  The compounding amount of the peroxide-based crosslinking agent is such that the peroxide-based crosslinking is performed with respect to 100 parts by weight of the fluorine-based rubber composed of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether in the fluorine-based rubber composition. 0.1 parts by weight to 5 parts by weight of the agent. If the peroxide-based crosslinking agent is less than 0.1 parts by weight, it is difficult to obtain the desired effect, and if the peroxide-based crosslinking agent exceeds 5 parts by weight, cracks and coarse bubbles tend to occur during foaming, which is not preferable. .

  In this embodiment, in order to efficiently perform the crosslinking reaction, a polyfunctional monomer can be used in combination as a crosslinking aid. Examples of the polyfunctional monomer include divinylbenzene, trimethylolpropane trimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, and triallyl trimellitic acid. Esters, triallyl isocyanurate, trimethallyl isocyanurate, ethyl vinylbenzene and the like can be used. These polyfunctional monomers may be used alone or in combination of two or more. The amount of the crosslinking aid added is 0.1 to 5 parts by weight with respect to 100 parts by weight of the fluororubber composed of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether in the fluororubber composition. It is preferable to use within the range of parts by weight.

  In this embodiment, carbon black, titanium oxide, silica, clay and other fillers as required, and liquid fluororubber, dioctyl sebacate, tricresyl phosphate, etc. are optionally added as plasticizers. I can do it.

  The foam obtained by the production method of the present embodiment was evaluated for chemical resistance, and as Comparative Example 1, “DF700 (trade name)” manufactured by Mifuku Kogyo Co., Ltd. as an example of a conventional fluororubber foam. The result of the immersion test compared with is shown in FIG. The chemical resistance was evaluated by preparing a test piece having a length of 50 mm, a width of 20 mm, and a thickness of 3.5 mm as a foam, and using a methyl ethyl ketone (MEK) solution as a chemical, and a stainless steel container. Pour a methyl ethyl ketone solution into it, put a test piece of foam into it, immerse it at room temperature (room temperature) for 200 hours, take out the test piece, measure its dimensions and weight, and compare the volume change rate with the numerical value before immersion. The quality was judged from the weight change rate.

[Comparative Example 1]
As Comparative Example 1, as an example of a conventional fluororubber foam, the formulation and manufacturing method of “DF700 (trade name)” manufactured by Mifuku Kogyo Co., Ltd. are as follows. 100 parts by weight of fluororubber (“G-702 (trade name)” manufactured by Daikin Industries, Ltd.), 20 weight of MT (Medium Thermal) carbon black (“Thermax N-990 (trade name)” manufactured by CANCARB Ltd)) 3 parts by weight of magnesium oxide (“Kyowa Mag MA-150 (trade name)” manufactured by Kyowa Chemical Industry Co., Ltd.) and calcium hydroxide (“CALDIC-2000 (trade name)” manufactured by Omi Chemical Industry Co., Ltd.) 6 parts by weight, 5 parts by weight of thermally expandable microcapsules (“Matsumoto Microsphere-F-30 (trade name)” manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), “Azodicarbonamide” (manufactured by Sankyo Kasei Co., Ltd. A composition comprising 4 parts by weight of CAP-250 (trade name) ") is kneaded with a water-cooled open roll having a roll temperature of 35 ° C or lower, and 160 ° C. The above-mentioned mixture is filled in a mold in a press heated to, and heated under pressure for 20 minutes to obtain a foam.

100 g of “GA-15 (trade name)” manufactured by Daikin Industries, Ltd., which is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, and azodicarbonylamide (Sankyo Chemical Co., Ltd.) as a pyrolytic foaming agent “Cermic CAP250 (trade name)” manufactured by Nippon Oil & Fats Co., Ltd. 0.15 g as a peroxide-based crosslinking agent, and “Nippon Kasei Co., Ltd.” 0.15 g of TMAIC (trade name) and 1 g of carbon black (“Asahi 60 (trade name)” manufactured by Asahi Carbon Co., Ltd.) were mixed with an 8-inch open roll and heated at a temperature of 140 ° C. For 10 minutes and further heated in an oven at 160 ° C. for 5 minutes to obtain a foam. The density of the foam was measured and found to be 0.42 g / cm ³ . As shown in FIG. 1, the chemical resistance was superior to the fluorine-based foam of Comparative Example 1 (“DF700 (trade name)” manufactured by Mifuku Kogyo Co., Ltd.).

In Example 1, except that 1.5 g of azodicarbonylamide (“Cermic CAP250 (trade name)” manufactured by Sankyo Chemical Co., Ltd.) 1.5 g was changed to 3 g as the pyrolytic foaming agent. A foam was obtained under the same conditions as the same formulation. The density of the foam was measured and found to be 0.25 g / cm ³ .

[Comparative Example 2]
In Example 1, except that 1.5 g of azodicarbonylamide (“Celmic CAP250 (trade name)” manufactured by Sankyo Chemical Co., Ltd.) 1.5 g was changed to 12 g as the pyrolytic foaming agent. An attempt was made to obtain a foam under the same conditions as the same formulation, but the foam was defoamed from the surface of the foam, and a good foam could not be obtained.

[Comparative Example 3]
Example 1 except that “G801 (trade name)” manufactured by Daikin Industries, Ltd. made of vinylidene fluoride is used as a fluorine-based rubber made of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether. A foam was obtained in the same manner. In Comparative Example 3, as in Comparative Example 2, an attempt was made to obtain a foam under the same formulation and conditions as in Example 1. However, the foam was defoamed from the surface of the foam and was good. No foam can be obtained.

  The foam using a fluororubber made of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether obtained by the present invention has not only heat resistance but also chemical resistance, particularly durability against esters and ketone chemicals. Is effective for sealing materials and packing applications.

Claims (2)

A foam using a fluorine-based rubber made of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether,
A foam having a specific gravity within a range of 0.1 to 0.5 and bubbles having an average bubble diameter of 100 μm or less. It is a manufacturing method of the foam according to claim 1,
0.5 parts by weight to 10 parts by weight of a pyrolytic foaming agent and 0.1 parts by weight to 5 parts by weight of a peroxide-based crosslinking agent with respect to 100 parts by weight of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether. A method for producing a foam, comprising mixing a part.

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