JP4192730B2 - Continuous production method of functional membrane - Google Patents

Description

The present invention relates to a method for continuously producing a functional membrane. More specifically, the present invention relates to a method for continuously producing a functional film that can sufficiently remove a polymer adhering to the surface and can continuously obtain a functional film free from scratches and deformation.
INDUSTRIAL APPLICABILITY The present invention can be used in batteries such as fuel cells and redox flow batteries, various devices in electrolysis, separation membranes, and the like.

  A film made of a perfluorosulfonic acid polymer is widely known as a functional membrane for a fuel cell. In addition, a functional membrane in which a porous membrane is filled with various functional polymers such as a polymer obtained by polymerizing a monomer having an ion exchange group is also known. For example, a fuel cell that is one type of electrochemical device using an electrolyte membrane in which a porous membrane is filled with a polymer electrolyte body is known. In recent years, the performance of this fuel cell has been greatly improved due to improvements in electrolyte membrane and catalyst technology, and is being developed for low-emission vehicles. Such a functional membrane is produced by impregnating a porous sheet with a functional monomer or the like and then polymerizing the functional monomer or the like. In the functional membrane produced by this method, the functional polymer is generated not only inside the pores of the porous sheet but also on the surface of the sheet, and the performance of the functional membrane deteriorates, so it is necessary to remove excess polymer. There is. Conventionally, this excess polymer is removed by a method such as scraping with a plastic blade or the like. Also disclosed is a method of removing the ion exchange resin on the surface of the microporous membrane by bringing it into contact with an oxidizing agent such as hydrogen peroxide or ozone (see, for example, Patent Document 1).

JP 2001-157823 A

The above-mentioned method is known as a method for removing excess polymer, but it can be easily and sufficiently removed without causing damage or deformation to the functional film. There is a need for a method of continuously producing functional membranes.
The present invention has been made in view of the above-described situation. The polymer impregnated and adhered to the continuously conveyed porous sheet is swollen, and the swollen polymer adhering to the sheet surface is sprayed. It aims at providing the continuous manufacturing method of the functional film | membrane which can obtain a functional film | membrane without a damage | wound, a deformation | transformation, etc. by spraying and removing a liquid or gas.

The present invention is as follows.
1. An impregnation / attachment step in which a porous resin sheet is continuously conveyed and impregnated with a polymer precursor containing a monomer having a functional functional group is adhered to the porous resin sheet, and the polymer precursor is polymerized. A polymerizing step for producing a polymer, and a polymer-filled / adhered sheet in which the polymer is filled and adhered to the porous resin sheet, and a liquid capable of swelling the polymer is contacted to swell the polymer; A functional membrane comprising a swelling polymer removing step of removing the swelling polymer attached to the surface of the polymer-filled / attached sheet by spraying at least one of a spray liquid, a gas and a gas-liquid mixture. Continuous manufacturing method.
2. In the swelling polymer removing step, the polymer-filled / adhered sheet is conveyed by a rotating roll, and the polymer-filled / adhered sheet in contact with the rotating roll and in the vicinity thereof are in contact with the rotating roll. The above 1. is performed by spraying at least one of a spray liquid, a gas, and a gas-liquid mixture from the surface opposite to the surface. A method for continuously producing the functional film according to 1.
3. In the swelling polymer removing step, the polymer-filled / adhered sheet is conveyed while being in contact with the smooth surface, and the polymer-filled / adhered sheet in contact with the smooth surface and the vicinity thereof are in contact with the smooth surface. The above-mentioned 1. is performed by spraying at least one of a spray liquid, a gas, and a gas-liquid mixture from a surface opposite to the surface on which the spray is performed . A method for continuously producing the functional film according to 1.
4). The swelling polymer removing step is performed while the polymer filling / adhering sheet is conveyed from below to above. To 3. The continuous manufacturing method of the functional film of any one of these.
5. The swelling polymer removal step is performed while the transport surface of the polymer filling / adhering sheet is transported while being inclined at an angle of 10 ° or more with respect to a horizontal plane. To 3. The continuous manufacturing method of the functional film of any one of these.
6). The swelling polymer removing step is performed in combination with an operation of bringing the attached polymer removing tool into contact with at least one surface of the polymer filling / attaching sheet to which the swelling polymer adheres. To 5. The continuous manufacturing method of the functional film of any one of these.
7). The above 1. in which the spray liquid is sprayed water. To 6. The continuous manufacturing method of the functional film of any one of these.
8). 1. The gas is air. To 7. The continuous manufacturing method of the functional film of any one of these.

According to the continuous production method of the functional film of the present invention, the swelling polymer adhered to the surface of the polymer-filled / adhered sheet can be easily and sufficiently removed, and a functional film having excellent performance is obtained. Can do.
In addition, the swelling polymer removal step conveys the polymer filling / adhering sheet by the rotating roll, and the portion in contact with the rotating roll and the polymer filling / adhering sheet in the vicinity thereof is opposite to the surface in contact with the rotating roll. When carried out by spraying at least one of spray liquid, gas and gas-liquid mixture from the surface, and the swelling polymer removal step conveys the polymer-filled / adhered sheet in contact with the smooth surface, and on the smooth surface When it is performed by spraying at least one of spray liquid, gas and gas-liquid mixture from the surface opposite to the surface in contact with the smooth surface to the polymer filling / adhesion sheet in the vicinity and in contact Since high pressure liquid or gas can be sprayed, the swelling polymer adhering to the surface can be sufficiently removed, and high In deformation of the spraying be functional film can be prevented.
Furthermore, when the swelling polymer removal step is performed while the polymer filling / adhering sheet is conveyed from below to above, the removed swelling polymer quickly flows down to prevent reattachment.
In addition, when the swelling polymer removal step is carried out while the conveying surface of the polymer filling / adhering sheet is conveyed with an inclination of 10 ° or more with respect to the horizontal plane, the removed swelling polymer quickly flows down the inclined surface downward. Re-adhesion is prevented.
Furthermore, when the swelling polymer removal step is performed in combination with the operation of bringing the attached polymer removal tool into contact with at least one surface of the polymer filling / attaching sheet to which the swelling polymer adheres, the swelling attached to the surface of the polymer filling / attaching sheet The polymer can be removed more efficiently.
Further, when the spray liquid is sprayed water and when the gas is air, the operation is easy, which is preferable in terms of the working environment, and the functional film is not altered.

Hereinafter, the present invention will be described in detail.
(1) Impregnation and adhesion step The “polymer precursor” contains a monomer having a functional functional group. As the “monomer having a functional functional group” (hereinafter referred to as “functional monomer”), various monomers can be used depending on the purpose and application of the functional film. Examples of the functional monomer include a monomer having an ion exchange group when the functional membrane is an electrolyte membrane used for a fuel cell or the like, and various polar groups when the functional membrane is a separation membrane used for concentration or the like. And a monomer having an ion exchange group when the functional membrane is an electrolyte membrane used for electrolysis or the like.

As the functional monomer having an ion exchange group used when the functional membrane is an electrolyte membrane such as a fuel cell, a monomer having a proton acidic group that is excellent in performance when used as an electrolyte membrane for a fuel cell is preferable. The monomer having a proton acidic group is a compound having a polymerizable functional group and a protonic acid in one molecule. For example, 2- (meth) acrylamide-2-methylpropanesulfonic acid, 2- (meth) acrylamide- 2-methylpropanephosphonic acid, styrenesulfonic acid, (meth) allylsulfonic acid, vinylsulfonic acid, isoprenesulfonic acid, (meth) acrylic acid, maleic acid, crotonic acid, vinylphosphonic acid, acidic phosphoric acid group-containing (meth) An acrylate etc. are mentioned. The ion exchange group may be an anion exchange group, and examples of the monomer having an anion exchange group include basic monomers such as vinylpyridine and p-vinyl-N, N-dimethylbenzylamine, which have these. The amino group is quaternized to develop anion exchange ability.
“(Meth) acryl” means “acryl and / or methacryl”, “(meth) allyl” means “allyl and / or methallyl”, and “(meth) acrylate” means “acrylate and / or methacrylate”. (The same applies to the following).

Moreover, the monomer which has a functional group which can be converted into an ion exchange group can also be used. Examples of this monomer include salts, anhydrides and esters of the above compounds. When the acid residue of the monomer used is a derivative such as a salt, an anhydride, or an ester, proton conductivity can be imparted by making it into a protonic acid type after polymerization. Furthermore, a monomer having a site capable of introducing an ion exchange group after polymerization can be used. Examples of this monomer include monomers having a benzene ring such as styrene, α-methylstyrene, chloromethylstyrene, and t-butylstyrene. It is done. Examples of the method for introducing an ion exchange group into these monomers include a method of sulfonation with a sulfonating agent such as chlorosulfonic acid, concentrated sulfuric acid, sulfur trioxide and the like.
As the monomer having a protonic acid group, a vinyl compound having a sulfonic acid group excellent in proton conductivity and a vinyl compound having a phosphoric acid group are preferable, and 2- (meth) acrylamide-2-methylpropanesulfonic acid having high polymerizability is preferable. Is particularly preferred.

  When the functional membrane is a separation membrane used for concentration or the like, a monomer having an affinity for the separation target can be used. Furthermore, when the functional membrane is an electrolyte membrane used for electrolysis or the like, a monomer having an ion exchange group can be used. Examples of the monomer include (meth) acrylic acid, vinyl sulfonic acid, maleic acid, croton. Acid, styrene sulfonic acid, (meth) allyl sulfonic acid, protonic acid such as 2- (meth) acrylamido-2-methylpropane sulfonic acid, and basic such as vinyl pyridine and p-vinyl-N, N-dimethylbenzylamine And monomers.

  The polymer precursor may be composed only of a functional monomer, and may contain a functional monomer and another monomer copolymerizable with the functional monomer (hereinafter referred to as “other monomer”). . Furthermore, a functional monomer and a crosslinkable monomer may be contained, and a functional monomer, other monomers, and a crosslinkable monomer may be contained. Moreover, components other than polymer precursors, such as a polymerization initiator and various additives, can be impregnated and adhered to the porous resin sheet as necessary. The polymerization initiator and various additives can be impregnated and adhered separately from the polymer precursor. Furthermore, at least one of a polymerization initiator and various additives and a polymer precursor can be mixed and impregnated and adhered at the same time. Other than the polymer precursor such as a polymerization initiator and various additives All of the components can be mixed with the polymer precursor and impregnated and deposited simultaneously. In addition, each component such as a functional monomer can be impregnated and adhered as it is if it itself is a liquid, particularly a liquid having a viscosity that can be impregnated. Furthermore, each component such as a functional monomer can be impregnated and adhered to a solution or dispersion obtained by dissolving or dispersing each component in a solvent. When impregnating and adhering as a solution or dispersion, use a solution or dispersion in which all components such as functional monomers, other monomers, crosslinkable monomers, polymerization initiators, various additives, etc. are dissolved or dispersed. It is preferable to impregnate and attach each component simultaneously. In this way, each component can be impregnated uniformly in the pores of the porous resin sheet.

  When the functional monomer is a monomer having an ion exchange group used for an electrolyte membrane of a fuel cell or the like, as the other monomer, a monomer having no proton acidic group is used to adjust the degree of swelling of the polymer. It can be included. This other monomer is not particularly limited as long as it is a monomer copolymerizable with a monomer having an ion exchange group, a crosslinkable monomer, etc., (meth) acrylic acid esters, (meth) acrylamides, maleimides, styrenes , Organic acid vinyls, allyl compounds and methallyl compounds. In addition, as other monomers when the functional membrane is a separation membrane used for concentration, etc., in order to adjust the polarity, monomers with low polarity such as cyclohexyl acrylate and lauryl acrylate, and maleimide, vinyl pyrrolidone, etc. A monomer having a polar group can be contained. Furthermore, as the other monomer when the functional membrane is an electrolyte membrane used for electrolysis or the like, the same monomers as in the case of the electrolyte membrane of the fuel cell or the like can be used.

  By introducing a cross-linked structure into the polymer using a cross-linkable monomer, a polymer that does not dissolve in the liquid used to swell the polymer but swells can be obtained. For example, in the case of a water-soluble resin, it dissolves when water is used as a liquid, but it can be made into a polymer that swells without being dissolved in water by crosslinking. This crosslinkable monomer has two or more polymerizable functional groups in one molecule. For example, N, N′-methylenebis (meth) acrylamide, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) Examples include acrylate, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, divinylbenzene, bisphenol di (meth) acrylate, isocyanuric acid di (meth) acrylate, tetraallyloxyethane, triallylamine, diallyloxyacetate and the like. In addition, the crosslinkable monomer is not limited to one having a carbon-carbon double bond, and a bifunctional or higher functional epoxy compound can be used although the reaction rate is slightly low. When this epoxy compound is used, a cross-linking bond is formed by reacting with a carboxyl group of the polymer. Only one type of crosslinkable monomer may be used, or two or more types may be used.

The “porous resin sheet” is not swelled by a liquid capable of swelling a polymer (hereinafter referred to as “swellable liquid”). The term “does not swell” means that the area increase rate is 5% or less when a porous resin sheet having a size of 100 × 100 mm is immersed in a swellable liquid at 25 ° C. for 1 hour. The area increase rate is 2% or less, particularly 1% or less, and more preferably 0.5% or less.
Area increase rate (%) = [(Area after immersion in swelling liquid−Area before immersion in swelling liquid) / Area before immersion in swelling liquid] × 100

  As the porous resin sheet, those made of various resins can be used. The resin used for forming the porous resin sheet is not particularly limited. Polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride- Vinyl chloride resins such as olefin copolymers, polytetrafluoroethylene, polytrifluoroethylene, polychlorotrifluoroethylene, poly (tetrafluoroethylene-hexafluoropropylene), poly (tetrafluoroethylene-perfluoroalkyl ether), etc. And fluorine resins, polyamide resins such as nylon 6 and nylon 66, aromatic polyimide, aramid, polysulfone, and polyether ether ketone. As the resin, a polyolefin resin excellent in mechanical strength, chemical stability, chemical resistance and the like is preferable. Furthermore, a porous resin sheet that is cross-linked by electron beam irradiation, chemical cross-linking with a cross-linking agent, or the like and has improved heat resistance or the like is preferable. In addition, a porous resin sheet that has a high strength by stretching or the like and is capable of suppressing deformation due to external force is preferable. Furthermore, the porous resin sheet which gave bridge | crosslinking and extending | stretching etc. together is more preferable.

The porosity of the porous resin sheet depends on the type of polymer and the product in which the porous resin sheet is used, but it is preferably 5 to 95%, particularly 5 to 90%, and more preferably 20 to 80%. The average pore diameter is preferably in the range of 0.001 to 100 μm, particularly preferably 0.01 to 1 μm, although the preferred range varies depending on the type of polymer and the product in which the porous resin sheet is used. Further, the porosity of the porous resin sheet is 5 to 95%, particularly 5 to 90%, more preferably 20 to 80%, and the average pore diameter is 0.001 to 100 μm, particularly 0.01 to 1 μm. More preferred. When the porous resin sheet is used, for example, for an electrolyte membrane of a fuel cell, if the porosity is too small, the number of ion exchange groups per area becomes too small and the output decreases. On the other hand, when the porosity is too large, the strength is undesirably lowered. Further, the thickness of the porous resin sheet also depends on the type of polymer, the product in which the porous resin sheet is used, and the like, for example, in the case of a fuel cell, it is preferably 200 μm or less, preferably 1 to 150 μm, particularly 5 to 100 μm, More preferably, it is 5-50 micrometers. If the porous resin sheet is too thin, the strength decreases and the amount of methanol permeated also increases. On the other hand, if it is too thick, the membrane resistance becomes excessive and the output of the fuel cell decreases, which is not preferable.

  The tensile elastic modulus of the porous resin sheet is preferably 500 to 5000 MPa, particularly 1000 to 5000 MPa. Moreover, it is preferable that the tensile fracture strength of a porous resin sheet is 50-500 MPa, especially 100-500 MPa. Furthermore, it is more preferable that the tensile modulus of the porous resin sheet is 500 to 5000 MPa, particularly 1000 to 5000 MPa, and the tensile breaking strength is 50 to 500 MPa, particularly 100 to 500 MPa. If the tensile modulus of the porous resin sheet is at least one of 500 to 5000 MPa and the tensile breaking strength is 50 to 500 MPa, the swelling of the polymer filled in the pores of the porous resin sheet is sufficiently suppressed, and the porous resin sheet is porous. The deformation of the quality resin sheet is suppressed. Furthermore, it has moderate rigidity and, for example, when a functional membrane is used as an electrolyte membrane of a fuel cell, cracks do not occur due to pressure molding at the time of electrode joining and tightening at the time of battery assembly. The fuel cell is heated during operation, but is preferably a porous resin sheet that has sufficient heat resistance at this temperature and does not easily deform even when an external force is applied.

  The impregnation and adhesion of the polymer precursor, etc. are impregnated with the polymer precursor in the pores of the long porous resin sheet that is continuously sent and conveyed, and the polymer precursor on the surface of the porous resin sheet. This can be done by attaching a body or the like. The impregnation and adhesion methods are not particularly limited, and (1) a polymer precursor, (2) a mixture in which a compound other than a monomer such as a polymerization initiator and various additives is blended with the polymer precursor, and (3) a polymer. Solutions or dispersions in which the precursor is dissolved or dispersed in a solvent, or (4) solutions in which a mixture of a compound other than a monomer such as a polymerization initiator and various additives is dissolved or dispersed in a solvent. Or the method of immersing a porous sheet in a dispersion liquid etc., the method of spraying said (1) thru | or (4) etc. on a porous resin sheet, etc. are mentioned. As a method of impregnation and adhesion, a method of immersing the porous resin sheet in the above (1) to (4) is preferable. With this method, the polymer precursor or the like can be uniformly impregnated and adhered by the porous resin sheet. In particular, the polymer precursor is preferably uniformly impregnated in the pores of the porous resin sheet. For that purpose, the porosity of the porous resin sheet and the average pore diameter of the pores, and the polymer precursor or the solution It is preferable to select a method of impregnation while taking into account the viscosity and the like, and to set conditions for impregnation. The temperature, time, and the like during the impregnation and adhesion are not particularly limited, but the temperature is preferably 0 to 120 ° C, particularly 5 to 80 ° C, and more preferably 5 to 50 ° C. The time is preferably 0.1 seconds to 1 hour, particularly 1 to 600 seconds, and more preferably 1 to 300 seconds. More preferably, the temperature is 0 to 120 ° C., particularly 5 to 80 ° C., further 5 to 50 ° C., and the time is 0.1 second to 1 hour, particularly 1 to 600 seconds, and further 1 to 300 seconds. .

(2) Polymerization process The method of polymerizing the polymer precursor impregnated and adhered to the porous resin sheet in the impregnation and adhesion process is not particularly limited, and it is by irradiation with active energy rays such as thermal polymerization, electron beam, and ultraviolet rays. It can be carried out by polymerization or the like. Among these methods, polymerization by electron beam or ultraviolet irradiation is preferred.
The electron beam is excellent in permeability to the porous resin sheet. In particular, when the porous resin sheet is made of a hydrocarbon-based polymer, a crosslinked structure can be introduced into the polymer depending on irradiation conditions. Furthermore, polymerization by electron beam irradiation is also preferable in that a radical photopolymerization initiator or the like is not required. In addition, it is preferable that a crosslinked structure is introduced because swelling of the polymer filled in the pores of the porous resin sheet is suppressed and dimensional change of the porous resin sheet is suppressed.

When polymerizing a polymer precursor by irradiating with an electron beam, the accelerating voltage of the irradiated electron beam depends on the type of the polymer precursor and the like, but is preferably 150 to 500 KeV, particularly 150 to 200 KeV. If the acceleration voltage is too low, it is difficult to generate an electron beam, and if it is too high, the porous resin sheet may deteriorate and the strength may decrease. The irradiation amount also depends on the type of polymer precursor, but is preferably 1 to 600 Mrad, particularly 2 to 200 Mrad, and more preferably 2 to 100 Mrad. When the irradiation amount is less than 10 mJ / cm ² , it cannot be sufficiently polymerized, and when it exceeds 10,000 mJ / cm ² , the porous resin sheet is deteriorated and the strength is lowered, which is not preferable.

  After polymerization by irradiation with an electron beam, it can be post-cured by heating or irradiation with ultraviolet rays, if necessary. The polymerization initiator for that purpose can also be previously blended with the polymer precursor. Examples of the polymerization initiator include azo compounds such as 2,2′-azobis (2-amidinopropane) dihydrochloride, ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide, cumene hydroperoxide. , Peroxides such as di-t-butyl peroxide, redox initiators combining the above peroxides with reducing agents such as sulfites, bisulfites, thiosulfates, formamidinesulfinic acid, ascorbic acid, Azo radical polymerization initiators such as 2,2'-azobis- (2-amidinopropane) dihydrochloride and azobiscyanovaleric acid. These polymerization initiators may use only 1 type and may use 2 or more types.

  Further, as a curing method, a polymerization method by irradiation with ultraviolet rays, which can easily control the polymerization reaction and obtain a desired functional film with a simple process and high productivity, is also preferable. In the method of curing by irradiation with ultraviolet rays, it is more preferable to previously dissolve or disperse the radical photopolymerization initiator in a solution or dispersion containing the monomer precursor. As the radical photopolymerization initiator, those described below can be used. Furthermore, the blending amount of the radical photopolymerization initiator is 0.001 to 1% by mass, particularly 0.001 to 0.5% by mass, more preferably 0.01 to 0% when the polymer precursor is 100% by mass. It is preferable that it is 0.5 mass%.

  When polymerizing the polymer precursor by irradiating with ultraviolet rays, it is preferable to attach a radical photopolymerization initiator that generates radicals by ultraviolet rays in advance to the surface of the pores of the porous resin sheet. The radical photopolymerization initiator is preferably attached by impregnating the solution or dispersion containing the initiator into the pores of the porous resin sheet and then removing the solvent. If it does in this way, an initiator can be made to adhere uniformly in the pore of a porous resin sheet.

The radical photopolymerization initiator is not particularly limited, but an aromatic ketone radical polymerization initiator that can generate a radical by extracting hydrogen from a carbon-hydrogen bond such as benzophenone, thioxanthone, or thioacridone is preferable.
Examples of the benzophenone initiator include methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone. 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxy-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethyl Ammonium chloride, 4,4′-dimethylaminobenzophenone, 4,4′-diethylaminobenzophenone and the like can be mentioned. Examples of the thioxanthone initiator include thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and 2-ethylthioxanthone. Furthermore, examples of the thioacridone initiator include thioacridone.

As the radical photopolymerization initiator, benzoin-based initiators, acetophenone-based initiators, benzyl-based initiators, and the like can also be used.
Examples of the benzoin initiator include benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin ethyl ether, and benzoin isobutyl ether. Examples of the acetophenone-based initiator include acetophenone, propiophenone, diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- ( 4- (Methylthio) phenyl) -2-monforinopropane-1, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenyl And propan-1-one, 1- (4- (2-hydroxyethoxy) -phenyl) -2-hydroxydi-2-methyl-1-propan-1-one, and the like. Furthermore, examples of the benzyl initiator include benzyl. Only one type of radical photopolymerization initiator may be used, or two or more types may be used.

  The radical photopolymerization initiator is preferably used as a solution or dispersion as described above. The concentration of the initiator in this solution or dispersion is preferably 0.01 to 10% by mass, particularly preferably 0.1 to 5% by mass. When this concentration is less than 0.01% by mass, polymerization may not be sufficiently performed. On the other hand, if it exceeds 10% by mass, crystals of the initiator may precipitate and block some of the pores of the porous resin sheet. If some of the pores are blocked as described above, the polymer precursor or the like may not be sufficiently filled. Moreover, it may not be filled uniformly over the entire porous resin sheet, which is not preferable anyway.

(3) Swelling polymer removal step The “liquid” that can swell the polymer is not particularly limited, and a swellable liquid that can swell to such an extent that the polymer can be easily removed can be used. Also, from the viewpoint of productivity, a short time contact, for example, a continuous porous resin sheet is supplied to produce a polymer-filled / adhered sheet, and the polymer adhering to the surface of this polymer-filled / adhered sheet When the liquid and the swellable liquid are brought into contact with each other, the liquid is preferably capable of sufficiently swelling the polymer.
The ability to swell this polymer means that the increase rate of mass is 1 or more when 1 g of polymer is immersed in an excessive amount of swellable liquid at 25 ° C. for 1 hour in a mass ratio. The mass increase rate is 500 times or less, preferably 100 times or less, and more preferably 10 times or less.
Mass increase ratio (times) = [(mass after immersing in swellable liquid−mass before immersing in swellable liquid) / mass before immersing in swellable liquid]

  The swellable liquid can be selected from water or various organic solvents depending on the type of polymer. In the case of a polymer that swells in water, such as a hydrophilic polymer or a polymer in which a cross-linked structure is introduced into a water-soluble polymer, an organic solvent compatible with water, such as water, methanol, ethanol, or the like as a swellable liquid, or these organic solvents A mixed solvent of water and water can be used. Such a swellable liquid has no effect on the human body and the environment, has a small effect, is easy to handle, and is easy to remove. For example, if the polymer is composed of a functional monomer such as 2- (meth) acrylamide-2-methylpropanesulfonic acid used for the production of the electrolyte membrane of the fuel cell and has a crosslinked structure introduced, By contact, it can be swollen enough to be easily removed only by contact for a relatively short time of 0.1 to 60 seconds, particularly in a wide temperature range of 1 to 80 ° C. On the other hand, in the lipophilic polymer, an organic solvent capable of swelling the polymer can be used. This solvent is preferably selected and used depending on the kind of polymer, the predetermined degree of swelling, and the like.

  The contact between the polymer for swelling the polymer and the swellable liquid can be performed by immersing the polymer-filled / adhered sheet in the swellable liquid. Moreover, it can also carry out by spraying a swellable liquid on a polymer filling and adhesion sheet. The method of immersing the polymer-filled / adhered sheet in the swellable liquid can swell the polymer sufficiently and easily over the entire surface of the polymer-filled / adhered sheet. Moreover, it is preferable that the temperature at the time of making a polymer and a swelling liquid contact is -10-100 degreeC, especially 0-50 degreeC, and it is more preferable that it can fully swell at room temperature (20-35 degreeC). The time for contacting the polymer with the swellable liquid is preferably 0.1 to 300 seconds, particularly preferably 0.1 to 100 seconds, and more preferably 1 to 60 seconds. Furthermore, the temperature is −10 to 100 ° C., particularly 0 to 50 ° C., further room temperature (20 to 35 ° C.), and the time is 0.1 to 300 seconds, particularly 0.1 to 100 seconds, and further 1 to 60 seconds. It is preferable that The contact temperature and contact time are particularly preferably such that the temperature is closer to room temperature and the time is shorter. Moreover, it is preferable to set this contact temperature and contact time by each kind etc. of a polymer and a swelling liquid.

Removal of the swollen polymer can be achieved by transporting the polymer-filled / adhered sheet to the polymer-filled / adhered sheet in the vicinity of the portion where the sheet is conveyed by a rotating roll and in contact with the rotating roll. It can carry out by spraying at least 1 sort of (refer FIG. 2). In this method, the polymer-filled / adhered sheet can be continuously conveyed, and the swelling polymer adhering to the surface of the sheet can be continuously removed. The swelling polymer is removed by conveying the polymer-filled / adhered sheet in contact with the smooth surface and spraying liquid, gas and gas / liquid on the polymer-filled / adhered sheet in contact with the smooth surface and the vicinity thereof. It can also carry out by spraying at least 1 sort (s) of a mixture (refer FIG. 4). Also in this case, by moving the polymer filling / adhering sheet on the smooth surface, the sheet can be continuously conveyed, and the swelling polymer adhering to the surface of the polymer filling / adhering sheet can be continuously removed.
In these removal methods, since the polymer-filled / adhered sheet is supported on a rotating roll or a smooth surface, a high-pressure spray liquid, gas or gas-liquid mixture, for example, 0.01 to 10 MPa is supported on the supported part. In particular, it is possible to spray a spray liquid with a pressure of 0.1 to 1 MPa, and efficiently remove the swelling polymer adhering to the surface of the polymer filling / adhering sheet without causing damage to the polymer filling / adhering sheet. Can do.
The vicinity of the portion where the polymer-filled / adhered sheet is in contact with the rotating roll or smooth surface is a range in which the sheet can be continuously conveyed without being damaged even if sprayed liquid or gas is sprayed. The separation between the rotating roll or smooth surface and the polymer filling / attaching sheet (the length between the surface of the polymer filling / attaching sheet perpendicular to the polymer filling / attaching sheet and the surface of the rotating roll or smooth surface, That is, the distance between both surfaces is preferably in the range of 2 cm or less, more preferably 1 cm or less.
Further, in the removal of the swelling polymer, the swelling polymer such as a lump must be removed, but the swelling polymer may remain in the form of a thin film on the surface of the polymer-filled / adhered sheet. The contact area with other members, for example, electrodes in a fuel cell can be increased.

  The removal of the swollen polymer can also be performed by conveying the polymer-filled / adhered sheet from below to above and spraying at least one of a spray liquid, a gas, and a gas-liquid mixture on at least one surface of the sheet. In this case, a plurality of rotating rolls can be arranged in the vertical direction, and the rolls can be conveyed while contacting the polymer-filled / adhering sheet with these rolls. (See FIG. 2). In this case, as described above, it is more preferable to spray at least one of a spray liquid, a gas, and a gas-liquid mixture on the polymer-filled / attached sheet in the portion in contact with the rotating roll. Further, the swelling polymer is removed by transporting the polymer filling / adhering sheet with the conveying surface inclined at an angle of 10 ° or more with respect to the horizontal plane, and spraying liquid, gas and gas-liquid mixture on at least one surface of the polymer filling / adhering sheet. It can also be performed by spraying at least one kind. This inclination may be an inclination in the conveying direction of the polymer-filled / adhered sheet, or an inclination in the width direction of the long sheet (see FIG. 4). Furthermore, the conveyance surface may be inclined with respect to the horizontal plane in both the conveyance direction and the width direction. This inclination angle is preferably 20 ° or more, particularly preferably 30 ° or more. In these methods, the removed swollen polymer quickly flows downward and prevents reattachment.

  The removal of the swollen polymer is performed by spraying at least one of a spray liquid, a gas, and a gas-liquid mixture on the polymer filling / adhering sheet to which the swollen polymer adheres, and simultaneously bringing the adhered polymer removing tool into contact with the sheet. You can also. If it does in this way, the adhering swelling polymer can be removed more easily and the usage-amount of the spraying liquid etc. which are sprayed can also be reduced. The attached polymer removing tool may be any as long as the functional film is not damaged and does not cause damage such as deformation. Examples of the attached polymer removing tool include a brush roll (see FIG. 3), a rubber blade, and the like. The polymer adhering to the surface can also be removed by passing the polymer-filled / adhered sheet through a narrow gap slightly wider than its thickness. In FIG. 3, the brush roll is in contact with the portion where the polymer filling / adhering sheet is in contact with the rotating roll, but is not in contact with the rotating roll unless the functional film is deformed. You may contact in the part.

Various types of nozzles can be used when spraying at least one of a spray liquid, a gas, and a gas-liquid mixture on the polymer-filled / attached sheet. Examples of the nozzle include a fan type, a straight full cone type, and a hollow cone type. This nozzle may be fixed as long as the spray liquid or the like can be sprayed evenly onto the surface of the polymer-filled / attached sheet. It can also be swung as needed. By swinging the nozzle, the spray liquid or the like can be sprayed evenly over the entire surface of the polymer-filled / adhered sheet, and the adhering swollen polymer can be efficiently removed.
Furthermore, when using a spray liquid such as sprayed water or a gas-liquid mixture containing water, etc., the water containing the swelling polymer removed from the surface of the polymer-filled / adhered sheet is filtered through a resin net or the like. Thus, the amount of water used can be reduced by separating the polymer and water and reusing the water.

  The spray liquid, gas, and gas-liquid mixture sprayed onto the polymer-filled / adhered sheet in order to remove the swelling polymer are not particularly limited, but those inert to the porous resin sheet and the polymer are preferable. Moreover, the thing which does not affect a human body, an environment, etc. is preferable. Such spray liquid is preferably sprayed water, and the gas is preferably air. Furthermore, humidified air in which water vapor is contained in the air can also be used as the gas-liquid mixture. In particular, when water can be used as the swelling liquid, it is preferable to use water as the liquid for removing the swelling polymer, air as the gas, and humidified air as the gas-liquid mixture. In this way, since an organic solvent or the like is not used in all steps from the impregnation and adhesion step to the polymer removal step, it can be made a more preferable method for the human body, the environment, and the like.

The impregnation, adhesion process, polymerization process and polymer removal process are performed continuously. In this continuous production method, a long porous resin sheet is continuously delivered to impregnate and adhere to a polymer precursor, polymerization thereof, swelling of the produced polymer, and swelling adhering to the surface of the polymer-filled / attached sheet. The removal of the polymer is performed by a continuous process, and the resulting long functional film can be made into a product by a method such as continuous winding. Moreover, in order to manufacture a functional film efficiently, when there exists another process, it is performed continuously also including another process.
This continuous manufacturing method can be performed, for example, by a process as shown in FIG. That is, a long porous resin sheet 1 that is continuously fed is brought into contact with a solution or dispersion 2 containing a polymer precursor or the like placed in a container (impregnation, adhesion process), and then this polymer The polymer precursor is polymerized by irradiating the adhering porous resin sheet with an electron beam, ultraviolet rays or the like from the active energy ray irradiation source E (polymerization step), and then the obtained polymer The swellable liquid 3 is sprayed from the nozzle N1 to the filling / adhering sheet 11 to swell the adhering polymer, and then the spraying liquid 4 for removing the polymer is sprayed from the nozzle N2 to the surface of the polymer filling / adhering sheet. The adhering swelling polymer is removed (polymer removal step), and then when the sprayed liquid such as sprayed water is used, the resulting functional film 5 is continuously dried by the drying device H. It can be produced efficiently wound on. Furthermore, in order to protect the product, it is possible to wind up while laminating a protective film 6 made of polyester, polyolefin, fluororesin or the like on at least one side (both sides in FIG. 1) of the functional film to be wound.
Other processes other than the impregnation, adhesion process, polymerization process, and polymer removal process include a drying process after the polymer removal process, an inspection process after this drying process, a humidity control process, and the like. Moreover, a slitting process, a cutting process, etc. may be provided as needed. These other steps are also carried out as a series of continuous steps along with the impregnation, adhesion step, polymerization step and polymer removal step.

  When the functional membrane is an electrolyte membrane, the electrolyte membrane is useful as an electrolyte membrane in a solid polymer fuel cell, particularly a direct methanol fuel cell. Thus, when using an electrolyte membrane in a fuel cell, the electrolyte membrane electrode assembly is sandwiched between two electrodes provided with a catalyst such as platinum and then integrated by a heating press or the like. Then, the assembly can be used by being incorporated in a fuel cell.

Example 1
90 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid and 10 parts by mass of N, N′-methylenebisacrylamide were used as a polymer precursor, and this polymer precursor and an ultraviolet polymerization initiator (Ciba Specialty Chemical) were used. 2 parts by mass of a product name “Darocur 1173” manufactured by the company and 2 parts by mass of a surfactant were dissolved in 100 parts by mass of water to prepare a solution. Thereafter, as shown in FIG. 1, the polyethylene porous resin sheet 1 is continuously fed and passed through the container in which the solution 2 is put, so that the porous resin sheet is impregnated with a polymer precursor, etc. The polymer precursor is polymerized by irradiating ultraviolet rays with a high-pressure mercury lamp, which is a source E of active energy rays, to an irradiation dose of 1000 mJ / cm ² to produce a polymer-filled / attached sheet 11, and then FIG. In this way, the polymer-filled / adhered sheet is conveyed while being brought into contact with about 1/3 circumference of a stainless steel roll R having a diameter of 30 cm. While the three cone type nozzles N1 are being swung, the polymer is swelled by spraying at a pressure of 0.2 MPa, and then, while the three cone type nozzles N2 are swung, 0. To remove swelling polymer by spraying water 41 to remove MPa swollen polymer attached to the surface of the polymer filling and adhering sheets at a pressure of. This process of swelling and removing the polymer was repeated three times to produce an electrolyte membrane 5. No bulk polymer remained on the surface of the obtained electrolyte membrane, and there was no damage such as scratches, deformations, and tears.

Example 2
While continuously feeding the polymer filling / attaching sheet 11 obtained by polymerizing the polymer precursor, as shown in FIG. 3, the polymer filling / attaching sheet is passed through a container containing water 31 as a swellable liquid. The polymer was swollen. Thereafter, the polymer filling / adhering sheet is passed between a stainless steel roll R having a diameter of 10 cm and a rotating brush roll B, and further, the polymer filling is performed at a pressure of 0.1 MPa while swinging the two fan-shaped nozzles N2. -The water 41 for removing the swelling polymer adhering to the surface of the adhesion sheet was sprayed to remove the swelling polymer. An electrolyte membrane was produced in the same manner as in Example 1 except that the polymer swelling and removal steps were repeated twice to obtain the electrolyte membrane 5. No bulk polymer remained on the surface of the obtained electrolyte membrane, and there was no damage such as scratches, deformations, and tears.

Example 3
While continuously feeding the polymer filling / attaching sheet 11 obtained by polymerizing the polymer precursor, as shown in FIG. 4, a plurality of the polymer filling / attaching sheets are arranged so that the conveying surface of the polymer filling / attaching sheet is inclined by θ = 30 ° from the horizontal plane. It is conveyed while being in contact with the smooth surface of the fixed plate S, and water 31 that is a swellable liquid from the opposite surface in the portion that is in contact with the fixed plate is 0.2 MPa while the three fan nozzles N1 are swung. Swelled by pressure, and then swollen the three fan-shaped nozzles N2 while spraying water 41 to remove the swollen polymer adhering to the surface of the polymer-filled / adhered sheet with a pressure of 0.2 MPa. Was removed. An electrolyte membrane was produced in the same manner as in Example 1 except that the polymer swelling and removal steps were repeated twice to obtain the electrolyte membrane 5. No bulk polymer remained on the surface of the obtained electrolyte membrane, and there was no damage such as scratches, deformations, and tears.
In addition, as each fixing plate, a stainless steel plate in which both end portions in the direction in which the polymer-filled / adhered sheet is conveyed is processed into a curved surface, and the surface in contact with the sheet is coated with a fluororesin is used. Further, the sprayed water 31 and 41 and the removed polymer were separated by filtration through a 300 mesh polyethylene net, and this water was circulated and reused.

Comparative Example 1
While continuously feeding the polymer-filled / attached sheet obtained by polymerizing the polymer precursor, the polymer was swollen by passing the polymer-filled / attached sheet through a container containing water as a swelling liquid. After that, the smooth tip of the polypropylene blade was brought into contact with the surface of the polymer-filled / adhered sheet conveyed upward, then sprayed with water and washed to adhere to the surface of the polymer-filled / adhered sheet. The swelling polymer was removed and the electrolyte membrane 5 was manufactured. Although the obtained electrolyte membrane had a function as an electrolyte as shown in Table 1 below, a block of polymer remained in some places, and there were some scratches caused by the blade being caught.

As described above, the proton conductivity and the methanol permeation flux of each of the electrolyte membranes of Examples 1 to 3 and Comparative Example 1 were measured by the following methods. The results are shown in Table 1.
(1) Measurement of proton conductivity The electrolyte membrane was immersed in water at 25 ° C. to swell, and thereafter, the electrolyte membrane was sandwiched between two platinum foil electrodes to prepare a specimen for measuring proton conductivity. . Using this specimen, impedance was measured with an impedance measuring device (manufactured by Hewlett-Packard Company, model “HP4192A”).
(2) Measurement of methanol permeation flux The pervaporation experiment at 50 ° C. was carried out using methanol / water with a mass ratio of 1/9 as the feed liquid, reducing the permeation side to a steady permeation flow rate. Details are as follows.
The electrolyte membrane was sandwiched between stainless steel cells, and the above supply liquid was placed on the top surface of the electrolyte membrane and stirred. Further, a heater and a resistance temperature detector were added to the supply liquid, and the temperature was controlled at 50 ° C. Furthermore, a vacuum pump was connected to the lower surface of the electrolyte membrane via a cold trap. In this way, the lower surface of the electrolyte membrane, that is, the permeation side was reduced in pressure, and the mixture of methanol and water vapor that permeated the electrolyte membrane in the cold trap was collected. Thereafter, the collected vapor (solidified in the cold trap) is heated, dissolved and taken out as a liquid, and the total permeation flux is measured from its mass, and the permeate vapor composition is measured by gas chromatographic analysis. . This measurement was continued until the membrane permeation performance became constant with respect to time, and the measured value when the membrane permeation performance became constant was evaluated as the steady-state permeability.

According to the results of Table 1, in the electrolyte membranes of Examples 1 to 3, the proton conductivity is 52 to 54 S / cm ² and the methanol permeation flux is 0.68 to 0.75 kg / m ² · h. It can be seen that it has excellent performance. Moreover, the external appearance was also favorable. On the other hand, in the electrolyte membrane of Comparative Example 1, the proton conductivity in the measurable part is 52 S / cm ² and the methanol permeation flux is 0.81 kg / m ² · h, which is comparable to the Example. However, the film surface was inferior because of damage such as scratches.

It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified embodiments within the scope of the present invention depending on the purpose and application. For example, in FIG. 2, the liquid or gas is sprayed on the portion where the polymer filling / adhering sheet is in contact with the rotating roll, but can also be sprayed on the portion not in contact with the rotating roll. Moreover, in FIG. 4, although a liquid or gas etc. are sprayed in the part which the polymer filling and adhesion sheet | seat is in contact with the smooth surface, it can also be sprayed in the part which is not in contact with the smooth surface. Furthermore, the shape, the number, and the like of the fixing plate S in FIG. 4 are not particularly limited, and may be long in the transport direction of the polymer filling / adhering sheet. The material thereof may be any of metals such as stainless steel and aluminum, and resins such as polyolefin and polyamide.
Further, the polymer-filled / adhered sheet can be transported so that the width direction thereof is perpendicular to the horizontal plane (corresponding to the case where θ in FIG. 4 is 90 °). In this way, it is possible to prevent re-adhesion of the removed swelling polymer in the same manner as when the transport surface is inclined with respect to the horizontal plane.

It is a flowchart which shows an example of the process for manufacturing a functional film. Explanatory drawing which shows the method of swelling a polymer by conveying a polymer filling and adhesion sheet | seat while making it contact with a rotary roll from the bottom upwards, and spraying water on at least one surface of this sheet | seat, and removing the adhering swelling polymer It is. The polymer filled and attached sheet is passed through a container containing water, which is a swellable liquid, to swell the polymer, and then sprayed with water, and the swollen polymer attached by contacting the rotating brush as the attached polymer removing tool It is explanatory drawing which shows the method of removing. An explanation of a method for removing the adhered swollen polymer by causing the transport surface of the polymer-filled / adhered sheet to be transported while being inclined at an angle of 30 ° with respect to the horizontal plane, and spraying water onto at least one surface of the sheet. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Porous resin sheet (polyethylene porous resin sheet), 11: Polymer filling / adhesion sheet, 2; Solution or dispersion containing polymer precursor, E; Active energy ray irradiation source, 3; Swellability Liquid, 31, water used as swellable liquid, N1; nozzle for spraying swellable liquid, 4; liquid for removing polymer, etc. 41; water for removing polymer, N2; for removing polymer Nozzle for spraying liquid such as water, H; drying device, 5; functional film, 6; protective film, R; roll, B; brush roll, S; fixed plate, F;

Claims (8)

An impregnation / adhesion step in which the porous resin sheet is continuously conveyed, the porous resin sheet is impregnated with a polymer precursor containing a monomer having a functional functional group, and adhered;
A polymerization process for polymerizing the polymer precursor to form a polymer, and a liquid capable of swelling the polymer in contact with the polymer filling / adhesion sheet in which the polymer is filled and adhered to the porous resin sheet And a swelling polymer removing step of removing the swelling polymer adhered to the surface of the polymer-filled / attached sheet by spraying at least one of a spray liquid, a gas, and a gas-liquid mixture. A method for continuously producing a functional film.   In the swelling polymer removing step, the polymer filling / adhering sheet is conveyed by a rotating roll, and the polymer charging / adhering sheet in the vicinity of and in contact with the rotating roll is in contact with the rotating roll. The continuous manufacturing method of the functional film of Claim 1 performed by spraying at least 1 sort (s) of a spray liquid, gas, and a gas-liquid mixture from the surface opposite to a surface. In the swelling polymer removing step, the polymer-filled / adhered sheet is conveyed while being in contact with the smooth surface, and the polymer-filled / adhered sheet in contact with the smooth surface and the vicinity thereof are in contact with the smooth surface. The continuous manufacturing method of the functional film of Claim 1 performed by spraying at least 1 sort (s) of a spray liquid, gas, and a gas-liquid mixture from the surface opposite to the surface which is carrying out.   The method for continuously producing a functional film according to any one of claims 1 to 3, wherein the swelling polymer removing step is performed while the polymer filling / adhering sheet is conveyed from below to above.   The functional film according to any one of claims 1 to 3, wherein the swelling polymer removing step is performed while conveying the transport surface of the polymer filling / adhering sheet with an inclination of 10 ° or more with respect to a horizontal plane. Continuous manufacturing method.   The said swelling polymer removal process is performed in any one of the Claims 1 thru | or 5 performed together with operation which makes an adhesion polymer removal tool contact at least one surface of the said polymer filling and adhesion sheet to which the said swelling polymer adheres. The continuous manufacturing method of the functional film as described.   The method for continuously producing a functional film according to any one of claims 1 to 6, wherein the spray liquid is sprayed water.   The method for continuously producing a functional film according to any one of claims 1 to 7, wherein the gas is air.

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