JP6245166B2 - Method for producing reinforced electrolyte membrane - Google Patents

Description

  The present invention relates to a method for producing a reinforced electrolyte membrane.

  A method of manufacturing a reinforced electrolyte membrane having a reinforced membrane by impregnating a porous membrane as a reinforced membrane with an electrolyte membrane from both sides is known (for example, Patent Document 1). In this method, an electrolyte membrane is laminated on both sides of a porous membrane, a belt press is brought into contact with one electrolyte membrane, the other electrolyte membrane is brought into contact with a heating roll, and the porous membrane is heated with a pair of heating rolls. And the electrolyte membrane on both sides thereof are pressurized to impregnate the porous membrane with the electrolyte membrane.

JP 2008-277288 A JP2011-222499A

  However, in the above technique, when one electrolyte membrane is in contact with the belt press and the other electrolyte membrane is in contact with the heating roll, each membrane is thermally expanded in response to a rapid temperature change. Since there is a difference in thermal expansion between the electrolyte membrane and the porous membrane, the difference in thermal expansion may cause wrinkles in the electrolyte membrane.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.
According to one embodiment of the present invention, a method for producing a reinforced electrolyte membrane produced by impregnating a reinforcing membrane with an electrolyte membrane is provided. The manufacturing method includes: a laminating step in which an electrolyte membrane is disposed on a porous membrane as a reinforcing membrane to form a laminated membrane; a preheating step in which the laminated membrane is preheated at a predetermined preheating temperature; A heating and impregnation step of impregnating the electrolyte membrane into the porous membrane by heating the heated laminated membrane at a predetermined heating temperature higher than the preheating temperature. The preheating temperature is different from the heating temperature in a difference in linear expansion coefficient of the laminated film before and after preheating due to the preheating temperature, and in a difference in linear expansion coefficient of the laminated film before and after heating due to the heating temperature. Is a temperature at which it becomes 5% or less.
According to the manufacturing method of this embodiment, the difference in the linear expansion coefficient of the laminated film before and after the preheating due to the preheating temperature and the difference in the linear expansion coefficient of the laminated film before and after the heating due to the heating temperature are set to 5 with respect to the heating temperature. % To prevent wrinkles generated by expansion of the laminated film by heating the laminated film at a preheating temperature lower than the heating temperature set to suppress the temperature to less than%, and then heating the laminated film at the heating temperature. it can.
Further, in the manufacturing method of the above aspect, the heating and impregnation step may include impregnating the porous membrane with the electrolyte membrane by heating and pressing the preheated laminated film at the heating temperature. Good.
According to the manufacturing method of this embodiment, the laminated film is heated to impregnate the electrolyte film with the reinforcing film, and by pressing, the impregnation of the reinforcing film into the electrolyte film can be promoted.
In addition, the present invention can be realized as the following forms.

(1) According to an embodiment of the present invention, method of manufacturing a reinforced electrolyte membrane manufactured by impregnating the electrolyte membrane to the reinforcing layer is provided. This manufacturing method includes: a laminating step in which an electrolyte membrane is disposed on a porous membrane as a reinforcing membrane to form a laminated membrane; a preheating step in which the laminated membrane is preheated at a predetermined preheating temperature; the heated the laminated film, by heating at a predetermined heating temperature to a temperature higher than the preheating temperature, a heating step of impregnating said electrolyte membrane to said porous membrane; comprises.
According to the manufacturing method of this embodiment, after the laminated film is heated at a preheating temperature lower than the heating temperature, the laminated film is heated at the heating temperature, whereby wrinkles generated due to the expansion of the laminated film can be suppressed. .

(2) In the manufacturing method of the above embodiment, the heating impregnation step, the laminated film was preheated by pressing with heating at the heating temperature, even impregnating the electrolyte membrane on the porous membrane Good.
According to the manufacturing method of this embodiment, together with impregnating a reinforcing film on the electrolyte membrane by heating the laminate film, it is possible to promote the impregnation of the reinforcing layer of the electrolyte membrane by pressing.

(3) In the manufacturing method of the above aspect, the preheating temperature includes a difference in linear expansion coefficient of the laminated film before and after the preheating by the preheating temperature, and a linear expansion of the laminated film before and after the heating by the heating temperature. It may be a temperature at which the difference in rate is equal to or less than a predetermined threshold.
According to the manufacturing method of this embodiment, the difference in the linear expansion coefficient of the laminated film before and after the preheating due to the preheating temperature and the difference in the linear expansion coefficient of the laminated film before and after the heating due to the heating temperature can be suppressed. Wrinkles generated by the expansion of the laminated film can be more effectively suppressed.

  Note that the present invention can be realized in various modes. For example, in addition to the manufacturing method of the reinforced electrolyte membrane, it can be realized in the form of a manufacturing apparatus of the reinforced electrolyte membrane.

It is explanatory drawing which shows the lamination apparatus of a reinforcement film | membrane and an electrolyte membrane. It is explanatory drawing which shows the impregnation apparatus of an electrolyte membrane. It is a manufacturing flowchart of a reinforced electrolyte membrane. It is explanatory drawing which shows the impregnation apparatus of the comparative form 1. It is explanatory drawing which shows the impregnation apparatus of the comparative form 2. It is explanatory drawing which compares the performance of a reinforced type electrolyte membrane. It is explanatory drawing of the presumed mechanism which a wrinkle generate | occur | produces. It is a graph which shows the relationship between the preheating temperature of a preheating roll, and the difference of the linear expansion coefficient of a laminated film.

FIG. 1 is an explanatory diagram showing a laminating apparatus 10 for a reinforcing membrane and an electrolyte membrane. The laminating apparatus 10 includes an electrolyte membrane manufacturing unit 100, a protective sheet bonding unit 110, and a reinforcing membrane / electrolyte membrane laminating unit 120. The electrolyte membrane manufacturing unit 100 forms an electrolyte membrane (hereinafter referred to as “electrolyte membrane 210”). As the electrolyte, a precursor of a perfluorosulfonic acid polymer having a fluorinated sulfuryl group (—SO ₂ F) at the end of the regular chain, such as a precursor of Nafion (registered trademark), can be used. In this embodiment, the electrolyte membrane manufacturing unit 100 uses the electrolyte precursor having an IEC of 1.3 to 1.8 meg / g to form the electrolyte membrane 210 having a thickness of 4 to 20 μm. In this embodiment, the precursor of the electrolyte having a sulfuryl fluoride group at the end of the regular chain is used. Instead, the precursor of the electrolyte having a sulfuryl chloride group (—SO ₂ Cl) at the end of the regular chain, or the rule An electrolyte having a sulfonic acid group (—SO ₃ H) group at the chain end may be used. The halogenated sulfuryl group (sulfuryl fluoride group, sulfuryl chloride group) of the electrolyte precursor can be easily converted to a sulfonic acid group (—SO ₃ H) group by hydrolysis treatment. In the present embodiment, the term “electrolyte” includes both the precursor of the electrolyte and the electrolyte.

  The protective sheet bonding unit 110 includes a pair of bonding rolls 112 and a protective sheet feeding roll 114. The protective sheet feeding roll 114 feeds the protective sheet 220. The protective sheet 220 is formed of a fluorine-based resin, for example, Teflon (Teflon is a registered trademark) or a hydrocarbon-based resin. The protective sheet bonding unit 110 closely adheres the electrolyte membrane 210 and the protective sheet 220 by passing the electrolyte membrane 210 and the protective sheet 220 between two rolls of the pair of bonding rolls 112. Let

  The reinforcing membrane / electrolyte membrane laminate 120 includes a pair of laminate rolls 122, a paste extruder 124, and a stretching machine 126. The paste extruder 124 mixes a fine powder of polytetrafluoroethylene (PTFE) and Isopar (Isopar is a registered trademark), and extrudes it into a band shape to form a band-shaped reinforcing film 230. The stretching machine 126 stretches the belt-like reinforcing film 230 to a thickness of 1 to 5 μm and a porosity of about 40 to 60%, and bakes at about 350 ° C. to form a reinforcing film 231 that is a porous film. For example, the stretching machine 126 may stretch the reinforcing film 230 by using a pair of rolls and pressing while passing the reinforcing film 230 therebetween. In the present embodiment, the reinforcing film / electrolyte film stacking unit 120 includes the paste extruder 124 and manufactures the reinforcing film 230, but a separately prepared reinforcing film 230 may be used.

  In this embodiment, polytetrafluoroethylene (PTFE) is used as the reinforcing film 230. However, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polysiloxane; methacrylates such as polymethyl methacrylate (PMMA). Styrene resins such as polystyrene, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin); polyamide; polyimide (PI); polyetherimide (PEI); polyamideimide Polyesterimide; Polycarbonate (PC); Polyacetal; Polyarylene ethers such as polyphenylene ether (PPO); Polyphenylene sulfide (PPS); Polyarylate; Polyaryl; Polysulfone (polysulfone); Polyethersulfone (PES) (polyethersulfone); Polyurethanes; Polyester resins such as polyethylene terephthalate (PET); Polyethers such as polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) Ether ketones; Polyacrylates such as polybutyl acrylate and polyethyl acrylate; Polyvinyl esters such as polybutoxymethylene; Polysiloxanes; Polysulfides; Polyphosphazenes; Polytriazines; Polycarboranes Polynorbornene; epoxy resin; polyvinyl alcohol; polyvinyl pyrrolidone; polydienes such as polyisoprene and polybutadiene; polyalkenes such as polyisobutylene; System resin, hexafluoropropylene resin, or may be used in the resin, such as hexafluoroacetone-based resin (such as a thermoplastic resin).

  In the pair of laminated rolls 122, the electrolyte membrane 210 having the protective sheet 220 is arranged on both surfaces of the reinforcing membrane 231, and 5 of “protective sheet 220 -electrolyte membrane 210 -reinforcing membrane 231 -electrolyte membrane 210 -protective sheet 220”. A laminated film 200 having a layer structure is formed. The laminated film 200 is sent to an impregnation apparatus in which the next process is performed.

  FIG. 2 is an explanatory view showing an impregnation apparatus 30 for an electrolyte membrane. The impregnation apparatus 30 includes a transport roll 310, a preheating roll 320, and a pair of heating rolls 330 and 340. The conveying roll 310 conveys the laminated film 200 to the preheating roll 320 and the pair of heating rolls 330 and 340 while applying a tension of 0.1 to 0.8 MPa to the laminated film 200. The preheating roll 320 is rotatably provided, and the laminated film 200 conveyed from the conveyance roll 310 comes into contact with the preheating roll 320 and then rotates along with the rotation of the preheating roll 320. It is conveyed along the circumferential surface.

  The first heating roll 330 is disposed downstream of the preliminary heating roll 320. The first heating roll 330 is also rotatably provided in the same manner as the preliminary heating roll 320, and the laminated film 200 that has been conveyed contacts the first heating roll 330 and then rotates the first heating roll 330. As a result, it is conveyed along the circumferential surface of the first heating roll 330. The arrangement relationship between the preheating roll 320 and the first heating roll 330 is, for example, that the length of the laminated film 200 until the laminated film 200 is separated from the preheating roll 320 and contacts the first heating roll 330 is 200 mm or less. Is set to be However, the present invention is not limited to this, and a range in which the temperature of the laminated film 200 heated by the preheating roll 320 can be maintained, or a difference in thermal expansion coefficient (linear expansion coefficient) described later is a threshold value Dth [%] ( It may be within a range that can be maintained at 5% or less in this example.

The first heating roll 330 is set to a heating temperature described later, and the preheating roll 320 is set to a preheating temperature described later that is lower than the heating temperature. The laminated film 200 is heated while being in contact with the preheating roll 320 and the first heating roll 330, particularly the first heating roll 330, the electrolyte film 210 is softened, and the softened electrolyte film 210 is reinforced. The membrane 231 is impregnated.

The second heating roll 340 is disposed so as to form a pair downstream of the first heating roll 330. The second heating roll 340 is also rotatably provided like the first heating roll 330, and the laminated film 200 receives a pressing force in the laminating direction by being sandwiched between the pair of heating rolls 330 and 340. . This pushing force, impregnation of the reinforcing film 231 softened electrolyte membrane 210 is accelerated.

  The heating temperature Th1 of the first heating roll 330 is set to a temperature at which the electrolyte membrane 210 can be softened, for example, about 200 to 260 ° C. In this example, it shall be set to 240 degreeC. The preheating temperature Tph1 of the preheating roll 320 is set to heat the laminated film 200 in order to raise the temperature of the laminated film 200 from the ambient temperature of the temperature before heating, usually room temperature Tn (25 ° C. in this example) to the heating temperature step by step. The temperature is set lower than the temperature Th1. As will be described later, the preheating temperature Tph1 is equal to the difference between the linear expansion coefficient of the laminated film 200 at the preheating temperature Tph1 and the linear expansion coefficient of the laminated film at the preheating temperature Tph1. Both of the differences in the linear expansion coefficient of the laminated film 200 at the heating temperature Th1 with respect to the rate are set to temperatures at which the threshold value Dth (5% in this example) or less can be set.

The heating temperature Th2 of the second heating roll 340 is set to be equal to or lower than the heating temperature Th1 of the first heating roll 330. In addition, since the 1st heating roll 330 is set to the high heating temperature Th1 of about 200-260 degreeC mentioned above in order to fully soften the electrolyte membrane 210, it is comprised using metal rolls. On the other hand, the main purpose of the second heating roll 340 is to promote impregnation by pressing the reinforcing film 231 of the laminated film 200 by the pair of heating rolls 330 and 340. For this reason, heating temperature Th2 should just be more than the temperature which can maintain softening of the electrolyte membrane 210. FIG. Therefore, the second heating roll 340 is often configured using a rubber roll having high elasticity. Therefore, it is difficult to set the heating temperature Th2 of the second heating roll 340 to the same temperature as the heating temperature Th1 of the first heating roll 330, and a temperature lower than the heating temperature Th1 according to the heat resistant temperature of the rubber. Set to For example, the temperature is set to about 170 to 190 ° C. In this example, it is set to 180 ° C. However, the second heating roll 340 can also be a metal roll like the first heating roll 330. In this case, the heating temperature Th2 of the second heating roll 340 is also the first heating roll 340. What is necessary is just to set to the same temperature as heating temperature Th1 of the roll 330. FIG.

The pressing force (also referred to as “nip pressure”) by the first heating roll 330 and the second heating roll 340 includes a heating temperature Th1 of the first heating roll 330, a heating temperature Th2 of the second heating roll 340, and a laminated film. 200 conveying speed (for example, 3 to 20 m / min), according to the conditions set for each of the pressure can be promoted impregnation of the reinforcement film 231 of the electrolyte membrane 210 by pressing, for example, 0.1 It is set to about 1 MPa. In this example, it is set to 0.4 MPa.

After the electrolyte membrane 210 is impregnated into the reinforcement film 231, the laminated film 200, as the side opposite to the side in contact with the first heating roll 330 is in contact with the second heating roll 340, the surface of the second heating roller 340 For example, it is conveyed with a tension of 0.5 MPa. The heating temperature Th2 of the second heating roll 340 is a temperature slightly lower than the heating temperature Th1 of the first heating roll 330, and the laminated film 200 is slowly conveyed while being transported on the second heating roll 340. The temperature decreases and the reinforced electrolyte membrane 201 is formed. The formed reinforced electrolyte membrane 201 is wound into a roll shape by a winding roll (not shown), for example.

  FIG. 3 is a flowchart of manufacturing a reinforced electrolyte membrane. Step S100 is performed by the reinforcing film / electrolyte film stacking apparatus 10 described with reference to FIG. In step S100, the electrolyte membrane 210 having the protective sheet 220 on both sides of the reinforcing membrane 231 is prepared, and these are laminated, so that "protective sheet 220-electrolyte membrane 210-reinforcing membrane 231-electrolyte membrane 210-protective sheet 220". A stacking process for forming the stacked film 200 having the five-layer structure is performed.

Steps S110 to S130 are executed by the impregnation apparatus 30 described with reference to FIG. In step S110, the preheating process of heating the laminated film 200 at the preheating temperature Tph1 is performed by bringing the laminated film 200 into contact with the preheating roll 320 on the preheating roll 320. In step S120, the laminated film 200 is brought into contact with the first heated roll 330 on the first heated roll 330, whereby the laminated film 200 is heated at the heating temperature Th1, thereby softening the electrolyte film 210, and the electrolyte. heating step of impregnating the membrane 210 to the reinforcing film 231 is performed. In step S130, the laminated film 200 is pressed (pressed) in the laminating direction using the pair of heating rolls 330 and 340 while maintaining the heated state, and the pressurization for promoting the impregnation of the electrolyte membrane 210 into the reinforcing film 231 is performed. An impregnation step is performed. Therefore, steps S120 and S130 correspond to the heat impregnation step of the present invention. Note that the pressure impregnation step in step S130 can be omitted. When the pressure impregnation step is omitted, the first and second heating rolls 330 and 340 are arranged apart from each other by a predetermined distance, and the first and second heating rolls 340 are not pressurized. the heating by the heating roll 330 and 340, may be performed impregnation of the reinforcement film 231 of the electrolyte membrane 210. In this case, the second heating roll 340 is preferably a heating roll capable of setting the heating temperature Th2 to the same temperature as the first heating roll 330 and the heating temperature Th1.

  FIG. 4 is an explanatory view showing an impregnation apparatus 31 of Comparative Example 1. The impregnation apparatus 31 of the comparative form 1 is not provided with a preheating roll, and the point that the belt 250 is attached to the laminated film 200 before the laminated film 200 is heated by the first heating roll 330 is the present embodiment. Different from the impregnation apparatus 30 of FIG. That is, in the impregnation apparatus 30 of this embodiment, the laminated film 200 is preheated by the preheating roll 320 before being heated by the first heating roll 330. On the other hand, the impregnation apparatus 31 of the comparative example 1 allows the laminated film 200 and the gripping belt 250 to pass between the pair of transport rolls 312a and 312b (also referred to as “nip roll 312”), while the pressure is 0. The belt 250 is attached to the laminated film 200 by applying a pressure of 0.05 to 0.4 Mpa. Thereafter, the laminated film 200 to which the belt 250 is attached is brought into contact with the first heating roll 330 and conveyed on the first heating roll 330. Other configurations and processes are basically the same as those in the present embodiment. However, the affixed belt 250 is peeled off when the reinforced electrolyte membrane 201 is separated from the second heating roll 340.

  FIG. 5 is an explanatory view showing an impregnation device 32 of Comparative Example 2. The impregnation apparatus 32 of the comparative form 2 does not include the preliminary heating roll 320, but instead includes the spiral roll 316 slightly downstream from the position where the laminated film 200 contacts the first heating roll 330. The spiral roll 316 has a groove shape inclined at an inclination angle of about 30 degrees. The spiral roll 316 extends the wrinkles at the end in the direction intersecting the transport direction of the laminated film 200. About another structure and process, it is the same as this embodiment.

  FIG. 6 is an explanatory diagram for comparing the results of the reinforced electrolyte membrane 201. In Examples 1 to 4, the impregnation apparatus 30 of the embodiment is used, and the preheating temperature Tph1 of the preheating roll 320 is sequentially set to 160 ° C (example) with respect to the heating temperature Th1 of 240 ° C of the first heating roll 330. 1), 170 ° C. (Example 2), 180 ° C. (Example 3), and 190 ° C. (Example 4). Example 5 was produced using the impregnation apparatus 31 of Comparative Example 1, and Example 6 was produced using the impregnation apparatus 32 of Comparative Example 2.

  The result was judged by the presence or absence of wrinkles in the reinforced electrolyte membrane 201. The presence or absence of wrinkles (buckling wrinkles) was visually observed over the entire length (about 50). If there were no wrinkles, it was judged as good (◯), and if there were wrinkles, it was judged as bad (x). In Example 5 according to Comparative Example 1 and Example 6 according to Comparative Example 2, wrinkles were found visually. Among Examples 1 to 4 according to the embodiment, in Example 2 where the preheating temperature Tph2 is 170 ° C. and Example 3 where the preheating temperature Tph2 is 180 ° C., wrinkles are not found visually, and Example 1 where the preheating temperature Tph2 is 160 ° C. In Example 4 at 190 ° C., wrinkles were found visually.

  FIG. 7 is an explanatory diagram of an estimation mechanism for generating wrinkles. When the laminated film 200 comes into contact with the heating roll, the reinforcing film 231, the two electrolyte membranes 210, and the two protective sheets 220 of the laminated film 200 try to thermally expand each according to the applied temperature and the linear expansion coefficient, and as a result As a result, the laminated film 200 is thermally expanded as a whole. At this time, in the laminated film 200, an expansion force F1 generated by thermal expansion, an elastic restoring force F2 for suppressing expansion deformation, and between the laminated film 200 and a contact surface (such as a heating roll) or between each layer are generated. The frictional force F3 that suppresses the elastic restoring force F2 is applied, and it is estimated that the presence or absence of wrinkles is generated by the balance of these three forces.

  In Example 5 of Comparative Example 1, it is presumed that the frictional force F3 is increased by the belt 250, and the expansion force F1 cannot be relaxed by the elastic restoring force F2, and wrinkles are generated. In Example 6 of Comparative Example 2, the surface layer portion where the force is exerted by the spiral roll 316 can be stretched, but the frictional force between the inner layers is increased, so that the stress (expansion force) accumulated by the thermal energy in the inner layer is increased. ) Is not able to be mitigated, and it is estimated that wrinkles occur.

  FIG. 8 is a graph showing the relationship between the preheating temperature of the preheating roll and the difference in the linear expansion coefficient of the laminated film. The solid curve in FIG. 8 indicates the laminated film 200 at the preheating temperature Tph1 of the preheating roll 320 relative to the preheating temperature Tph1 of the preheating roll 320 and the linear expansion coefficient of the laminated film 200 at room temperature Tn (25 ° C. in this example). The linear expansion coefficient difference Dec1 [%] (hereinafter, also referred to as “first linear expansion coefficient difference Dec1”) is shown. The dashed curve in FIG. 8 shows the laminated film at the heating temperature Th1 of the first heating roll 330 with respect to the linear heating coefficient of the laminated film 200 at the preliminary heating temperature Tph1 of the preliminary heating roll 320 and the preliminary heating temperature Tph1 of the preliminary heating roll 320. A relationship with a difference Dec2 [%] of the linear expansion coefficient of 200 (hereinafter, also referred to as “second linear expansion coefficient difference Dec2”) is shown. In the parentheses of each preheating temperature Tph1 on the horizontal axis, the difference of each preheating temperature Tph1 with respect to the heating temperature Th1 (240 ° C. in this example) is shown. The linear expansion coefficient was measured using a test piece of a laminated film 200 of 4 mm × 10 mm and using a thermomechanical analyzer (TMA) under a nitrogen environment, a load of 5 gf, and a temperature rising rate of 5 ° C./min. It was executed at.

  As shown in FIG. 8, the first linear expansion coefficient difference Dec1 indicates that the rate of increase increases when the preheating temperature Tph1 is higher than 160 ° C. Specifically, the first linear expansion coefficient difference Dec1 is 2% in Example 1 (Tph1: 160 ° C.), 3% in Example 2 (Tph1: 170 ° C.), and Example 3 (Tph1: 170 ° C.), as shown in FIG. 5% in Tph1: 180 ° C. and 8% in Example 4 (Tph1: 190 ° C.), which increases as the heating temperature Th1 is approached. That is, the difference Dec1 of the first linear expansion coefficient decreases and decreases as the preheating temperature Tph1 approaches the temperature before the preheating (normal temperature Tn: 25 ° C. in this example), and the preheating temperature Tph1 However, the rate of increase increases as the temperature approaches the heating temperature Th1 (240 ° C. in this example).

  8, the second linear expansion coefficient difference Dec2 is larger when the preheating temperature Tph1 is lower than 190 ° C., in other words, the difference with respect to the heating temperature Th1 is larger than −50 ° C. It shows the characteristic that the rate of increase is high at low temperatures. Specifically, as shown in FIG. 6, the second increase rate difference Dec2 is 2% in Example 4 (Tph1: 190 ° C.), 3% in Example 3 (Tph1: 180 ° C.), and Example 2 (Tph1). : 170 ° C.) and 5% in Example 1 (Tph1: 160 ° C.), 2%, and becomes higher as the heating temperature becomes lower than Th1 (240 ° C.). That is, the difference Dec2 in the second linear expansion coefficient decreases as the preheating temperature Tph1 approaches the heating temperature Th1 (240 ° C. in this example), and the increase rate decreases and the preheating temperature Tph1 becomes lower than the heating temperature Th1. As the value decreases, the rate of increase increases and increases.

  Here, the measured value of the linear expansion coefficient of the laminated film 200 is a total value reflecting the difference in the linear expansion coefficient between the respective layers, and the difference in the linear expansion coefficient after heating with respect to the measured linear expansion coefficient before heating. If the difference (hereinafter also referred to as “difference in expansion coefficient before and after heating”) increases, it is considered that the difference in linear expansion coefficient between layers also increases relatively. Therefore, the smaller the difference between the linear expansion coefficients before and after heating, the less the expansion force generated due to the difference in the linear expansion coefficient between the layers, and the less the occurrence of wrinkles. It is considered that the expansion force generated due to the difference in the linear expansion coefficient between the layers is increased and wrinkles are easily generated. Therefore, if the preheating temperature Tph1 of the preheating roll 320 is set to a temperature that satisfies the first linear expansion coefficient difference Dec1 and the second linear expansion coefficient difference Dec2 so that wrinkles do not occur, wrinkles are generated. It is considered possible to suppress this. In other words, the preheating roll 320 is set to the preheating temperature Tph1 at which the first linear expansion coefficient difference Dec1 and the second linear expansion coefficient difference Dec2 are equal to or less than a threshold value representing the difference in linear expansion coefficient that can suppress the generation of wrinkles. If the temperature is set, the generation of wrinkles can be suppressed.

  As shown in FIG. 6, in Example 1 (Tph1: 160 ° C.), the first linear expansion coefficient difference Dec1 is 2% and the second linear expansion coefficient difference Dec2 is 8%, and wrinkles are generated. ing. In Example 2 (Tph1: 170 ° C.), the first linear expansion coefficient difference Dec1 is 3% and the second linear expansion coefficient difference Dec2 is 5%, and wrinkles are not generated. Similarly, in Example 3 (Tph1: 180 ° C.), the first linear expansion coefficient difference Dec1 is 5% and the second linear expansion coefficient difference Dec2 is 3%, and wrinkles are not generated. In Example 4 (Tph1: 190 ° C.), the first linear expansion coefficient difference Dec1 is 8% and the second linear expansion coefficient difference Dec2 is 2%, and wrinkles are generated. From this result, the threshold Dth that can suppress the occurrence of wrinkles is 5% for both the first linear expansion coefficient difference Dec1 and the second linear expansion coefficient difference Dec2. Accordingly, if the preheating temperature Tph1 of the preheating roll 320 is set so that both the first linear expansion coefficient difference Dec1 and the second linear expansion coefficient difference Dec2 are equal to or less than the threshold value Dth (5%). It is thought that the generation of wrinkles can be prevented. As can be seen from the results of Examples 1 to 4, in this example, the preheating temperature Tph1 of the preheating roll 320 is in the range of 170 ° C. to 180 ° C., in other words, −70 ° C. to −60 with respect to the heating temperature Th1. If the temperature is set in the range of ° C., both the first linear expansion coefficient difference Dec1 and the second linear expansion coefficient difference Dec2 can be set to the threshold value Dth (5%) or less to prevent the generation of wrinkles. Can do.

  As described above, wrinkles occurred in Example 5 using the impregnation apparatus 31 of Comparative Example 1 and Example 6 using the impregnation apparatus 32 of Comparative Example 6. In contrast, in Examples 1 and 4 using the impregnation apparatus 30 of the embodiment, wrinkles were generated, but in Examples 2 and 3, generation of wrinkles could be suppressed. This is because the laminated film 200 is preheated at the preheating temperature Tph1 (170 ° C in Example 2 and 180 ° C in Example 3), and then heated at the heating temperature Th1 (240 ° C), so that the lamination before and after the preheating is performed. The difference Dec1 in the linear expansion coefficient of the film 200 and the difference Dec2 in the linear expansion coefficient of the laminated film 200 before and after heating are less than the threshold Dth (5%) of the difference in linear expansion coefficient that can suppress the generation of wrinkles. It is thought that it was possible. From the above, in this embodiment, wrinkles can be prevented from being generated in the electrolyte membrane 210 by heating the multilayer film 200 stepwise.

  Note that the characteristic of the first linear expansion coefficient difference Dec1 in FIG. 8 shows the difference from the linear expansion coefficient at normal temperature Tn, where the temperature of the laminated film 200 before preheating is normal temperature Tn (25 ° C.). Even when the temperature is in the range of 150 to 160 ° C. or higher, similar characteristics are exhibited as the difference with respect to the linear expansion coefficient at other temperatures, for example, in the range of 15 to 40 ° C.

  The characteristic of the second linear expansion coefficient difference Dec2 in FIG. 8 is that the preheating temperature Tph1 and the heating temperature Th1 are 240 ° C., and the difference in the linear expansion coefficient at the preheating temperature Tph1 with respect to the linear expansion coefficient at the heating temperature Th1. Shows the relationship. When this is a relationship between the difference of the preheating temperature Tph1 with respect to the heating temperature Th1 and the difference of the linear expansion coefficient at the preheating temperature Tph1 with respect to the linear expansion coefficient at the heating temperature Th1, according to the heating temperature Th1, FIG. It is presumed to show a characteristic in which the second linear expansion coefficient difference Dec2 is shifted to the high temperature side or the low temperature side. For example, when the heating temperature Th1 is set to 220 ° C., it is estimated that the same characteristic as that obtained by shifting the second linear expansion coefficient difference Dec2 of FIG. 8 to the low temperature side by 20 ° C. is assumed. Therefore, in this case, it is estimated that the temperature range of the preheating temperature Tph1 of the preheating roll 320 in which the difference in linear expansion coefficient is equal to or less than the threshold value Dth (5%) extends to 150 ° C to 180 ° C.

  In the above embodiment, the threshold Dth is described as 5%. However, the threshold value Dth is not limited to this, and is a value that changes according to various conditions such as the material of the electrolyte membrane and the material of the reinforcing membrane. . For example, the threshold value Dth can vary from 3 to 7%.

  The threshold value Dth is a characteristic of the difference in linear expansion coefficient of the laminated film before and after preheating (corresponding to the first linear expansion coefficient difference Dec1 in FIG. 8) and a characteristic of the difference in linear expansion coefficient of the laminated film before and after heating. It may be set on the basis of (corresponding to the second linear expansion coefficient difference Dec2 in FIG. 8) and the result of an experiment examining whether or not wrinkles are generated at each preheating temperature Tph1.

  Moreover, in the said embodiment, although the structure which arrange | positions one preheating roll 320 and heats the laminated film 200 in two steps was demonstrated to the example, it is not limited to this, Two or more preheating rolls are used. It is good also as a structure which arrange | positions and heats the laminated film 200 in three or more steps. In this case, the difference in the linear expansion coefficient of the laminated film before and after the contact of each preheating roll and the difference in the linear expansion coefficient before and after the contact of the heating roll are the threshold values for the difference in linear expansion coefficient that can suppress wrinkles. What is necessary is just to set the preheating temperature of each preheating roll to the temperature low stepwise so that it may become below Dth.

  In the above embodiment, the electrolyte membrane 210 is disposed on both surfaces of the reinforcing membrane 231, but the electrolyte membrane 210 may be disposed on one surface of the reinforcing membrane 231.

  In the above embodiment, the case where a heating roll is used as a means for heating the laminated film has been described as an example. However, the present invention is not limited to this. For example, various heating means such as a heater may be used. Is possible.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above-described effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Laminating apparatus 30, 31, 32 ... Impregnation apparatus 100 ... Electrolyte membrane production part 110 ... Protection sheet bonding part 112 ... Bonding roll 114 ... Protection sheet feeding roll 120 ... Electrolyte film lamination part 122 ... Lamination roll 124 ... Paste extrusion Machine 126 ... Stretching machine 200 ... Laminated film 201 ... Reinforced electrolyte membrane 210 ... Electrolyte film 220 ... Protective sheet 230, 231 ... Reinforcing film 250 ... Belt 310 ... Transport roll 312 ... Nip roll 312a, 312b ... Transport roll 316 ... Spiral roll 320 ... Preheating roll 330, 340 ... Heating roll F1 ... Expansion force F2 ... Elastic restoring force F3 ... Friction force

Claims (2)

A method of manufacturing a reinforced electrolyte membrane manufactured by impregnating an electrolyte membrane reinforced membrane,
A laminating process in which an electrolyte membrane is disposed on a porous membrane as a reinforcing membrane to form a laminated membrane;
A preheating step of preheating the laminated film at a predetermined preheating temperature;
The laminated film being preheated by heating at a predetermined heating temperature to a temperature higher than the preheating temperature, a heating step of impregnating said electrolyte film on the porous membrane,
With
The preheating temperature is relative to the heating temperature, the difference in linear expansion coefficient of the multilayer film before and after preheating by the preheating temperature, and the difference in linear expansion coefficient of the multilayer film before and after the heating by the heating temperature Is a temperature which becomes 5% or less, The manufacturing method of a reinforced type electrolyte membrane. In the manufacturing method of the reinforced electrolyte membrane of Claim 1,
The heating impregnation step, the laminated film was preheated by pressing with heating at the heating temperature, wherein the porous membrane is impregnated with an electrolyte membrane, method for producing a reinforced electrolyte membrane.

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