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Liquid fluoropolymer composition and process for producing crosslinked fluorochemical

Inactive Publication Date: 2007-06-21
DAIKIN IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0120] The fluoropolymer liquid composition of the invention, which has the constitution described hereinabove, can produce cured articles excellent in mechanical characteristics and durability and undergoing only slight dimensional changes depending on the moisture content in an industrially efficient and stable manner.BEST MODES FOR CARRYING OUT THE INVENTION
[0121] The following examples illustrate the present invention more specifically. These examples are, however, by no means limitative of the scope of the present invention.

Problems solved by technology

However, they have problems.
In either case, however, decreases in mechanical strength will surely result.
However, there are problems; the crosslinking reaction already occurs in the molding machine and, therefore, it is difficult to control the crosslinking reaction, hence it is difficult to manufacture membranes constant in quality.
However, this method has a problem: it is difficult to obtain membranes large in size, so that batch production is unavoidable and mass production is difficult to make.
However, this document does not disclose the crosslinking of cast membranes formed from a solution, following by heating, for instance.
Further, the crosslinking agent is generally a large molecule and it is difficult for that agent to uniformly penetrate into the membranes; it is a problem that uniformly cured membranes are thus difficult to obtain.
However, the ˜SO2F type dispersion contains the emulsifier and / or initiator residue, which produces a problem, namely deteriorates the characteristics of the membranes obtained.

Method used

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  • Liquid fluoropolymer composition and process for producing crosslinked fluorochemical
  • Liquid fluoropolymer composition and process for producing crosslinked fluorochemical
  • Liquid fluoropolymer composition and process for producing crosslinked fluorochemical

Examples

Experimental program
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Effect test

example 1

[0122] A 500-ml SUS stainless steel autoclave was charged with 227.5 g of perfluorocyclobutane as a solvent, 168.2 g of perfluoro(ethyl vinyl ether)sulfonyl fluoride (PFSF, CF2═CFOCF2CF2SO2F) and 16.1 g of CF2═CFOCF2CF(CF3)OCF2CF2CN (CNVE), followed by deaeration. With stirring at 800 rpm and under the temperature condition of 30° C., tetrafluoroethylene [TFE] was introduced under pressure to a total pressure of 0.33 MPa and, then, 3.56 g of a 8% (by mass) solution of the initiator di(ω-hydroperfluorohexanoyl)peroxide in perfluorohexane was fed under pressure to initiate the polymerization reaction. During reaction, TFE was introduced from outside the system to maintain the pressure at constant level, and PFSF was introduced intermittently under pressure, in a total amount of 7.0 g, to compensate the PFSF consumption in the reaction. After the lapse of 2 hours, the unreacted TFE was discharged out of the system to thereby terminate the polymerization reaction. The state of stirring ...

example 2

[0124] An ice-cooled 300-ml autoclave equipped with a stirrer was charged with 150 ml of pure water, 3 g of ammonium perfluorooctanoate, 37 g of perfluoro(ethyl vinyl ether)sulfonyl fluoride (PFSF, CF2═CFOCF2CF2SO2F), 0.18 g of I(CF2)4I and 60 mg of ammonium persulfate and, after sufficient substitution of the inside space with tetrafluoroethylene [TFE], the inside was pressurized to 0.2 MPa with TFE, the system inside temperature was rapidly raised to 60° C., and TFE was additionally fed until arrival at a pressure of 0.8 MPa to thereby initiate the polymerization. The reaction was continued while additionally feeding TFE to compensate the decrease in pressure and maintain the pressure at 0.8 to 0.75 MPa. After the lapse of 6 hours, the autoclave was rapidly cooled to 20° C. or below and the unreacted TFE was released; the polymerization was thus stopped. A slightly turbid, transparent fluoropolymer aqueous dispersion (240 g) was obtained.

[0125] A portion of the fluoropolymer aque...

example 3

[0128] The procedure of Example 2 was followed in the same manner except that the amount of perfluoro(ethyl vinyl ether)sulfonyl fluoride (PFSF, CF2═CFOCF2CF2SO2F) was increased to 49 g. The PFSF content estimated from NMR spectrometry in a molten state at 300° C. was 23.4 mole percent, and the percentage of membrane expansion was 160%.

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Abstract

It is an object of the present invention to provide a liquid composition which comprises an acid / acid salt group-containing polymer and from which cured articles excellent in mechanical characteristics and undergoing only slight dimensional changes depending on the moisture content can be produced by application thereof to a substrate or impregnation of a porous material therewith. The present invention relates to a fluoropolymer liquid composition comprising a fluoropolymer liquid (A) which comprises a liquid medium and a crosslinkable functional group-containing crosslinkable fluoropolymer, wherein said fluoropolymer liquid (A) is a fluoropolymer liquid dispersion (AD) having, dispersed in a liquid dispersion medium, particles of a crosslinkable fluoropolymer (PD) containing acid / acid salt groups or organic groups capable of undergoing hydrolysis and thus being converted to carboxyl groups, or a fluoropolymer solution (AS) having, dissolved in a fluorosolvent or an alcohol / water mixed solvent, a crosslinkable fluoropolymer (PS) containing acid / acid salt groups or acid / acid salt groups precursors; said acid / acid salt groups are sulfonic acid groups, carboxyl groups or groups of the formula —SO2NR2R3, —SO3NR4R5R6R7, —SO3M11 / L, —COONR8R9R10R11 or —COOM21 / L, wherein R2 represents a hydrogen atom or M51 / L, R3 represents an alkyl group or an sulfonyl-containing group, R4, R5, R6, R7, R8, R9, R10 and R11 are the same or different and each represents a hydrogen atom or an alkyl group, and M1, M2 and M5 each represents a metal having a valence of L, said metal having a valence of L being a metal belonging to the group 1, 2, 4, 8, 11, 12 or 13 of the periodic table; and said acid / acid salt groups precursors are —SO2F, —SO2NR22R23 (wherein R22 and R23 are the same or different and each represents an alkyl group) or organic groups capable of undergoing hydrolysis and thus being converted to carboxyl groups.

Description

TECHNICAL FIELD [0001] This invention relates to a fluoropolymer liquid composition and to a method of producing a fluorine-containing cured article. BACKGROUND ART [0002] Fluorine-containing electrolyte membranes are mainly used in solid polymer fuel cells currently attracting attention. However, they have problems. For improving the power generating characteristics of fuel cells, such means is available as increasing the ion exchange capacity of the electrolyte membrane or diminishing the membrane thickness, for instance. In either case, however, decreases in mechanical strength will surely result. Since the membrane is firmly compressed during use, the membrane undergoes deformation and degradation due to the creep phenomenon, or is deteriorated due to repeated expansion and shrinkage on the occasions of starting and stopping power generation and, in extreme cases, pinholes are made, allowing mixing of hydrogen and oxygen with each other. [0003] For preventing fluorine-containing...

Claims

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Application Information

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IPC IPC(8): H01M8/10B05D5/12C08J3/24C08K5/18C08L27/12C09D127/12H01M8/02
CPCC08K5/18C09D127/12H01M8/0291H01M8/1023H01M8/1039H01M8/106H01M8/1081H01M8/1088Y02E60/523C08L27/12Y02E60/522H01M8/0289Y02P70/50Y02E60/50
Inventor ARASE, TAKUYATATEMOTO, MASAYOSHI
Owner DAIKIN IND LTD