JP5381367B2 - Method for producing fluororesin molded body - Google Patents

Description

  The present invention relates to a method for producing a fluororesin molded body, and more specifically, a fluororesin molded body that can obtain a fluororesin molded body excellent in mechanical strength and dimensional stability by low-temperature and short-time annealing. It relates to a manufacturing method.

  In the production of fluoropolymer moldings, it is effective to perform annealing after the molding process to form a thermally stable phase, control crystallinity, and remove residual stress. It has been known. In particular, an electrolyte polymer is typically formed by coating (casting) a dispersion and drying, so that it can be annealed at 120 ° C. or higher in order to obtain a continuous solid phase from dried and agglomerated polymer particles. It is disclosed in Patent Document 1 that it is effective.

  Further, in Patent Document 2, in order to obtain a film having sufficient physical strength and durability, it is higher by 10 ° C. or more than the glass transition point (Tg) of the fluorine-containing resin and leads to decomposition of the electrolyte polymer at a high temperature 210. Annealing at a temperature lower than 0 C is disclosed.

  Furthermore, the electrolyte membrane is desired to have a small dimensional change in the area direction due to a change in moisture content or a change in temperature. However, in this respect, Patent Document 3 discloses a technique for stretching during heating as a technique for improving dimensional stability. Then, it is disclosed that annealing is performed at a temperature higher than the stretching temperature.

  Furthermore, in Patent Document 4, as a method for producing an electrolyte membrane, the electrolyte membrane is brought into contact with a liquid that has a lower boiling point than the solvent used for the electrolyte polymer suspension and is a poor solvent for the electrolyte polymer. Thus, a technique for improving the drying speed is disclosed.

JP-T-2004-501484 (Claims etc.) JP-T 2007-511047 (Claims etc.) JP-A-2005-166329 (Claims) JP 2007-042582 A (claims, etc.)

  However, obtaining a continuous solid phase as in the technique described in Patent Document 1 is a necessary condition in the formation of an electrolyte membrane, but by itself, sufficient physical strength and dimensional stability are not sufficient in the environment where the electrolyte membrane is used. There is a problem that it cannot be obtained. Further, if the annealing is not sufficient, there is a problem that the electrolyte membrane may be damaged due to weak physical strength in the manufacturing process.

  In the technique described in Patent Document 2, if the fluororesin molded body contains a material having low heat resistance, it is necessary to anneal at a temperature commensurate with the heat resistance of the material. Alternatively, there is a problem that long annealing is required. On the other hand, in annealing at a temperature higher than the Tg of the fluororesin, since the fluororesin is softened, a support having high heat resistance is required, and there is a problem that the manufacturing cost increases. Also, the annealing temperature needs to be lower than the decomposition temperature of the electrolyte polymer, but even at the upper limit temperature that can be annealed, it may take a long time to obtain sufficient mechanical strength. is there.

  Furthermore, the method of stretching the electrolyte membrane during heating as in the technique described in Patent Document 3 is that the residual strain is relaxed by being exposed to changes in the temperature and humidity environment for a long period of use, and the effectiveness is reduced. There's a problem. Further, since strain remains in the electrolyte membrane, the degree of elongation until the membrane breaks is low, and it may be difficult to handle. Further, the stretching apparatus has a problem that the apparatus cost is high.

  Furthermore, the adoption of the step of contacting with a poor solvent as in the technique described in Patent Document 4 has the effect of improving the drying speed, but does not contribute to the improvement of physical properties by annealing. In any case, the actual situation is that until now it has not been possible to efficiently produce a fluorine-containing resin molded article excellent in mechanical strength and dimensional stability.

  Accordingly, an object of the present invention is to provide a method for producing a fluorinated resin molded article that can obtain a fluorinated resin molded article excellent in mechanical strength and dimensional stability by low-temperature and short-time annealing.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor annealed after swelling the formed fluororesin molded product intermediate with a good solvent, thereby reducing the annealing temperature or the annealing time, or It has been found that a fluorine-containing resin molded product having equivalent performance can be obtained even if both of these are performed, and the present invention has been completed.

That is, the method for producing a fluororesin molded product of the present invention includes the following steps a) and b),
a) molding a fluororesin that is an electrolyte polymer or a mixture containing the fluororesin to obtain a fluororesin molded article intermediate;
b) impregnating 25 to 500 parts by mass of a good solvent with respect to 100 parts by mass of the fluororesin in the obtained fluororesin molded product intermediate, and annealing at 120 to 200 ° C ;
It is characterized by having at least.

  According to the present invention, a fluorine-containing resin molded article excellent in mechanical strength and dimensional stability, particularly a fluorine-containing resin film, can be produced by annealing at a lower temperature and in a shorter time than conventional production methods. Such a decrease in the annealing temperature not only saves energy but also reduces the load on the film support and the like, and various support materials can be selected. In addition, according to the present invention, even when a material having a heat resistance lower than that of the fluorine-containing resin, which cannot be sufficiently annealed by the conventional manufacturing method, can be sufficiently annealed.

Hereinafter, preferred embodiments of the present invention will be described in detail.
(Process a))
The step a) of obtaining a fluororesin molded product intermediate by molding a fluororesin or a mixture containing the fluororesin is not particularly limited. For example, the fluororesin or the mixture containing the fluororesin is a solvent. In addition, the suspension, dispersion, or dissolved solution can be applied (applied) to the substrate as a coating solution, and dried to form a film.

  In the present invention, the coating method is not particularly limited, but as a specific example, the batch method includes a bar coater method, a spin coater method, a screen printing method, and the like. There is a measurement law. The post-weighing method is a method of applying an excessive coating liquid and removing the coating liquid so that a predetermined film thickness is obtained later. The pre-weighing method is necessary to obtain a predetermined film thickness. This is a method of applying an amount of coating liquid.

  As the post-measuring method, there are an air doctor coater method, a blade coater method, a rod coater method, a knife coater method, a squeeze coater method, an impregnation coater method, a comma coater method, etc. Examples include a transfer roll coater method, a gravure coater method, a kiss roll coater method, a cast coater method, a spray coater method, a curtain coater method, a calendar coater method, and an extrusion coater method. In order to form a uniform coating layer, a screen printing method and a die coater method are preferable, and a continuous die coater method is preferable in consideration of cost and mass production.

The fluorine-containing resin that can be used in the present invention is not particularly limited, but is preferably an electrolyte polymer because of its versatility. In particular, a perfluorocarbon polymer having a sulfonic acid group is preferable, and a copolymer including a unit based on tetrafluoroethylene and a unit based on perfluorovinyl ether having a sulfonic acid group is more preferable. Such a copolymer is usually obtained by copolymerization of tetrafluoroethylene and perfluorovinyl ether having a precursor group of a sulfonic acid group such as —SO ₂ F group, followed by hydrolysis and acidification. Can do.

  As the perfluorocarbon polymer having a sulfonic acid group (sulfonic acid type perfluorocarbon polymer), the following polymer (H) or the following polymer (Q) is preferable, and the polymer (Q) is particularly preferable.

  The polymer (H) is a copolymer having units based on tetrafluoroethylene (hereinafter referred to as “TFE”) and the following unit (1).

Unit (1):

(However, in the formula of unit (1), X is a fluorine atom or a trifluoromethyl group, m is an integer of 0 to 3, n is an integer of 1 to 12, and p is 0 or 1. .)

The polymer (H) is obtained by polymerizing a mixture of TFE and the following compound (2) to obtain a precursor polymer (hereinafter referred to as “polymer (F)”), and then —SO ₂ F in the polymer (F). It is obtained by converting the group into a sulfonic acid group. Conversion of the —SO ₂ F group into a sulfonic acid group is performed by hydrolysis and acidification treatment.

Compound (2):
_{CF 2 = CF (OCF 2 CFX} ) m -O p - (CF 2) n -SO 2 F (2)
(However, in the formula of compound (2), X is a fluorine atom or a trifluoromethyl group, m is an integer of 0 to 3, n is an integer of 1 to 12, and p is 0 or 1. .)

  Moreover, as said compound (2), the following compounds (21)-(23) are preferable.

_{CF 2 = CFO (CF 2)} n1 SO 2 F (21)
CF ₂ = CFOCF ₂ CF (CF ₃ ) O (CF ₂ ) _{n 2} SO ₂ F (22)
_{CF 2 = CF (OCF 2 CF} (CF 3)) m3 O (CF 2) n3 SO 2 F (23)
(However, in the formulas of the compounds (21) to (23), n1, n2, and n3 are integers of 1 to 8, and m3 is an integer of 1 to 3.)

  The polymer (Q) is a copolymer having units based on TFE and the following units (U1).

Unit (U1):

(However, in the formula of the unit (U1), Q ¹ is a perfluoroalkylene group which may have an etheric oxygen atom, and Q ² has a single bond or an etheric oxygen atom. And Y is a fluorine atom or a monovalent perfluoro organic group, and the single bond is a direct bond between a CY carbon atom and a SO ₃ H sulfur atom. The organic group means a group containing one or more carbon atoms.)

In the unit (U1), when the perfluoroalkylene groups of Q ¹ and Q ² have an etheric oxygen atom, the oxygen atom may be one or two or more. The oxygen atom may be inserted between the carbon atom-carbon atom bonds of the perfluoroalkylene group or may be inserted at the carbon atom bond terminal. Further, the carbon number of the perfluoroalkylene group is preferably 1 to 6, and may be linear or branched.

  The unit (U1) is preferably the following unit (M1), more preferably the following unit (M11) or the following unit (M12).

Unit (M1):

(However, in the formula of the unit (M1), R ^F11 is a single bond or a linear perfluoroalkylene group having 1 to 6 carbon atoms which may have an etheric oxygen atom, and R ^F12 Is a linear perfluoroalkylene group having 1 to 6 carbon atoms.)

Unit (M11):

Unit (M12):

  Further, the polymer (Q) may have a repeating unit based on another monomer (hereinafter referred to as “other unit”).

  The other unit is preferably a repeating unit based on a perfluoromonomer from the viewpoint of mechanical strength and chemical durability. The repeating unit based on the unit (1) having the above functional group or the following unit (M2 ) Based repeating units are preferred. As the unit (M2), the following unit (M21) or the following unit (M22) is more preferable.

Unit (M2):

(However, in the unit (M2) formula, t is an integer of 0 to 5, and q is an integer of 1 to 12.)

Unit (M21):

Unit (M22):

  The ion exchange equivalent (EW) of the polymer (Q) is preferably 400 to 900 g dry resin / equivalent (hereinafter referred to as “g / equivalent”), and more preferably 500 to 800 g / equivalent.

Furthermore, the mass average molecular weight of the polymer (Q) is preferably 1 × 10 ⁴ to 1 × 10 ^{7, and} more preferably 5 × 10 ^{4 to} 5 × 10 ⁶ .

The mass average molecular weight of the polymer (Q) can be evaluated by measuring the TQ value. The TQ value (unit: ° C.) is an index of the molecular weight of the polymer, and the extrusion amount when the polymer is melt-extruded under the condition of the extrusion pressure of 2.94 MPa using a nozzle having a length of 1 mm and an inner diameter of 1 mm is 100 mm. ^The temperature is ³ / sec. For example, a polymer having a TQ value of 200 to 300 ° C. corresponds to a mass average molecular weight of 1 × 10 ⁵ to 1 × 10 ⁶ although the composition of repeating units constituting the polymer differs.

  Further, the ion exchange capacity of the fluorine-containing ion exchange resin is preferably 1.1 to 1.8 meq / g dry resin, in terms of conductivity and gas diffusibility, and preferably 1.25 to 1.65 meq / g. A dry resin is more preferred.

  Moreover, in this invention, a non-fluorine-type exchange resin can be used as another component which can be contained in the mixture containing the said fluorine-containing resin. Examples of the non-fluorinated exchange resin include sulfonated polyarylene, sulfonated polybenzoxazole, sulfonated polybenzothiazole, sulfonated polybenzimidazole, sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetherethersulfone, and sulfonated. Examples include polyphenylene sulfone, sulfonated polyphenylene oxide, sulfonated polyphenylene sulfoxide, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone, sulfonated polyether ketone, sulfonated polyether ether ketone, sulfonated polyether ketone ketone, and sulfonated polyimide. It is done.

  The solvent contained in the coating solution may be a single solvent or a mixed solvent of two or more. For example, alcohols and fluorine-containing solvents can be used.

  As the alcohols, those having 1 to 4 carbon atoms in the main chain are preferable. For example, methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, tert-butyl alcohol and the like can be suitably used. . Moreover, when water is mixed with alcohol, the solubility of resin can also be improved.

  As a fluorine-containing solvent, the following are mentioned, for example. 1,1,1,2,3,3-hexafluoropropane, 1,1,2,2,3,3,4,4-octafluorobutane, 1,1,1,2,3,4,4, 5,5,5-decafluoropentane, 1,1,1,2,3,4,5,5,5,5-nonafluoro-2- (trifluoromethyl) -pentane, 1,1,1,2,3 , 3,4,4,5,6,6,6-dodecafluorohexane, 1,1,1,2,3,4,4,5,5,5-decafluoro-2- (trifluoromethyl)- Fluorocarbons such as pentane, 1,2,3,3,4,4-hexafluoro-1,2-di (trifluoromethyl) -cyclobutane, perfluorooctane, perfluoroheptane, perfluorohexane; 1,1-dichloro -1-fluoroethane, 2,2,2-trifluoro-1,1-di Hydrochlorofluorocarbons such as chloroethane, 1,1-dichloro-2,2,3,3-pentafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane; , 2-tetrafluoroethyl-1,1,1-trifluoroethyl ether, methyl-1,1,1,2,3,3-hexafluoropropyl ether and other fluoroethers; 2,2,2-trifluoroethanol , Fluorinated alcohols such as 2,2,3,3,3-pentafluoropropanol and 1,1,1,3,3,3-hexafluoroisopropanol.

  In the present invention, the viscosity of the coating solution is preferably in the range of 0.1 to 10 Pa · s. If it is less than 0.1 Pa · s, the viscosity is too low, and there is a possibility that the coating liquid flows out without being applied to the substrate when applied. On the other hand, if it exceeds 10 Pa · s, the viscosity is too high and uniform coating becomes difficult. Moreover, although the density | concentration of a coating liquid changes with solvents to be used, it is preferable that it is 0.1-50 mass% considering the viscosity of a coating liquid, and 0.1-30 mass% especially.

  In the present invention, the base material on which the coating liquid is applied is not particularly limited, and may be not melted during drying. Specifically, hydrocarbon films such as polyethylene terephthalate (hereinafter referred to as PET), polyethylene, polypropylene, polyimide, polytetrafluoroethylene, ethylene / tetrafluoroethylene copolymer, ethylene / hexafluoropropylene copolymer, tetra Fluorine-based films such as fluoroethylene / perfluoroalkyl vinyl ether copolymer and polyvinylidene fluoride can be mentioned.

(Process b))
Next, the method of impregnating the good solvent in the fluororesin molded product intermediate in step b) is not particularly limited, but specifically, the good solvent is cast on the fluororesin molded product intermediate. Examples thereof include a method, a method of immersing the fluororesin molded product intermediate in a good solvent, and a method of exposing the fluororesin molded product intermediate to the vapor of the good solvent.

  As a method of casting the good solvent on the fluororesin molded product intermediate, any of the coating methods similar to the above coating step can be used. The pre-measurement method is preferred for absorption. In particular, the non-contact spray coater method and die coater method are preferred to avoid deformation of the fluororesin molded product intermediate since the fluororesin softens, and the die coater method is preferred to obtain a uniform coating amount. preferable.

  In addition, the method of immersing the fluororesin molded product intermediate in a good solvent is not limited in terms of immersion time, solvent composition, etc., as long as the fluororesin in the fluororesin molded product intermediate can be impregnated with the good solvent. However, since the fluororesin may be dissolved in the solvent depending on the type of the solvent, it is preferable to adjust the immersion time, the solvent composition, and the like so that the impregnation amount is appropriate.

  Furthermore, the method of exposing the fluororesin molded product intermediate to the vapor of a good solvent is limited as long as the fluororesin of the fluororesin molded product intermediate can be impregnated with a good solvent. However, it is preferable to adjust the exposure time, temperature, and pressure so that the amount of impregnation is appropriate.

  The amount of good solvent impregnated in the fluororesin molded product intermediate varies depending on the good solvent used and the fluororesin used, but is 25 to 500 with respect to 100 parts by mass of the fluororesin in the fluororesin molded product intermediate. It is a mass part, Preferably it is 50-500 mass parts. If the amount of impregnation is lower than 25 parts by mass, volatilization of the good solvent will occur in concert with the progress of the annealing step. I can't get enough. On the other hand, when the amount exceeding 500 parts by mass is impregnated, the form of the fluororesin molded body itself may not be maintained.

  In the present invention, the good solvent means that the fluorine-containing resin permeates into the fluorine-containing resin at a temperature equal to or lower than the boiling point of the solvent when the fluorine-containing resin is mixed with the solvent so as to be 10% by mass of the total mass. A solvent that can eliminate insoluble resin.

  As such a good solvent, for example, fluorine-containing compounds, alcohols, glycol ethers, aromatic hydrocarbons and the like can be suitably used. Particularly preferably, in addition to the solvent used in step a) to form the fluororesin molded product intermediate, 2- (perfluorohexyl) ethanol, Asahi Clin AK-225 TM (Asahi Glass Co., Ltd., Japan, Tokyo), cellosolve, toluene, n-butyl alcohol and the like. Further, the good solvent may be a single solvent or a mixture of two or more.

  In addition, since it is preferable that the good solvent does not remain in the fluorine-containing resin molded body after annealing, the boiling point of the good solvent is preferably equal to or lower than the annealing temperature, and is the same as the solvent used in the step of forming the fluorine-containing resin molded body. It is particularly preferable to have a boiling property.

Even if the annealing temperature at the time of annealing is set lower than the conventional annealing temperature at which the fluorine-containing resin in the intermediate of the fluorine-containing resin molded article is not impregnated with a good solvent, the final fluorine-containing resin molded article In this case, the same performance as in the prior art can be obtained. Further, the annealing time can be shortened when the temperature is the same, or the same performance as the conventional one can be obtained even if the temperature is lowered and the time is shortened at the same time.

  Specifically, when the fluorine-containing resin is an electrolyte polymer, the annealing temperature is preferably 120 to 200 ° C. If the temperature is lower than 120 ° C, the effect of annealing may not be sufficiently obtained. If the temperature exceeds 200 ° C, the electrolyte polymer may be decomposed.

  In the present invention, the annealing time is typically 10 to 60 minutes. If the annealing time is too short, the annealing effect may not be obtained. On the other hand, considering the cost and mass production, it is disadvantageous to increase the annealing time.

  In the present invention, the amount of impregnation of the good solvent may decrease with time depending on the environment. Therefore, the annealing is preferably performed immediately after impregnation with the good solvent.

  In the present invention, the fluororesin molded body as the final molded body is preferably a fluororesin film. Such a fluorine-containing resin film can be suitably used for an electrolyte membrane of a fuel cell.

  In the present invention, the fluorine-containing resin molded body may be a layered molded body having a fluorine-containing resin as a constituent element. Such a layered molded body may be, for example, a layered porous body containing a metal catalyst and a catalyst carrier in addition to the fluororesin. Such a fluororesin porous body can be suitably used for a catalyst layer of a fuel cell.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

[Example 1]
Monomer _{A (CF 2 = CF 2)} , monomer _{B (CF 2 = CF-OCF} 2 CF (CF 3) -OCF 2 CF 2 SO 2 F) and monomer _{C (CF 2 = CF-OCF} 2 CF (OCF ₂ and _{CF 2 SO 2 F) -OCF 2} CF 2 SO 2 F), by copolymerizing the proportion of each monomer unit a: 82.6mol%, B: 7.8mol %, C: 9.6mol% A sulfonic acid type perfluorocarbon polymer precursor was obtained. This precursor is hydrolyzed and acidified to convert it to an ion exchange resin having an ion exchange capacity of 1.52 meq / g dry resin, and then a mixture of the ion exchange resin in water and ethanol is used. A solution (solid content concentration of 10% by mass) was prepared as a solvent. Then, a solution of cerium nitrate dissolved in distilled water is added to this solution, and a solution of a resin in which 10% of the sulfonic acid groups in the ion exchange resin are ion exchanged with Ce ³⁺ (hereinafter referred to as ion exchange resin (A)). Got. This solution is cast on a fluororesin (trade name: Film Aflex) product number 100N (thickness: 100 μm) manufactured by Asahi Glass Co., Ltd. by die coating, and then dried at 80 ° C. for 15 minutes, and consists of the ion exchange resin (A). A fluororesin film intermediate having a thickness of 25 μm was obtained.
The obtained fluororesin film intermediate was immersed in ethanol for 1 second to obtain a swollen body. Next, the swollen body was annealed at 140 ° C. for 15 minutes to obtain a fluororesin film as a final molded body.

[Example 2]
A fluororesin film was obtained in the same manner as in Example 1 except that a mixed solution of cellosolve and ethanol (mass ratio 1: 1) was used instead of ethanol and annealing was performed at 140 ° C. for 30 minutes.

[Comparative Example 1]
A fluorine-containing resin film was obtained in the same manner as in Example 1 except that the immersion in ethanol was not performed.

[Comparative Example 2]
A fluororesin film was obtained in the same manner as in Comparative Example 1 except that annealing was performed at 140 ° C. for 30 minutes.

[Comparative Example 3]
A fluororesin film was obtained in the same manner as in Example 2 except that acetone was used in place of ethanol for the formation of the swollen body. When acetone was used as a solvent, a swollen body could not be obtained.

(Evaluation method)
Since the moisture content is an index of mechanical strength and dimensional stability of the fluororesin film, the moisture content of the fluororesin films obtained in Examples 1 and 2 and Comparative Examples 1 to 3 was determined by the following method. .
After the fluororesin film was immersed in warm water at 80 ° C. for 60 hours, the fluororesin film was cooled to room temperature together with the warm water. The fluorine-containing resin film was taken out of the water, water droplets adhering to the surface were wiped off, and the mass of the fluorine-containing resin film at the time of water inclusion was immediately measured. Next, the fluorine-containing resin film was put in a glove box and left in an atmosphere of flowing dry nitrogen for 24 hours or more to dry the fluorine-containing resin film. Thereafter, the dry mass of the fluororesin film was measured in the glove box. From the difference between the moisture content of the fluorine-containing resin film and the dry mass, the mass of water absorbed by the fluorine-containing resin film when moisture was obtained was determined. From these measured values,
Moisture content = (mass of water absorbed by fluorinated resin film when hydrated / dry mass of fluorinated resin film) × 100
Thus, the moisture content (%) of the fluororesin film was determined.

  The evaluation results are shown with the water content of Example 1 as 100. It shows that mechanical strength and dimensional stability are so favorable that a numerical value is small. The obtained results are shown in Table 1 below.

  From Table 1, it can be seen that Example 1 can obtain a fluorine-containing resin molded article excellent in mechanical strength and dimensional stability as compared with Comparative Example 1 in which the annealing conditions are the same. In addition, it can be seen that Example 1 can still obtain good results even if the annealing time is shortened compared to Comparative Examples 2 and 3. Furthermore, in Example 2, it can be seen that a fluorine-containing resin molded article excellent in mechanical strength and dimensional stability can be obtained as compared with Comparative Examples 2 and 3 where the annealing conditions are the same.

Example 3
Monomer _{A (CF 2 = CF 2)} , monomer _{B (CF 2 = CF-OCF} 2 CF (CF 3) -OCF 2 CF 2 SO 2 F) and monomer _{C (CF 2 = CF-OCF} 2 CF (OCF ₂ and _{CF 2 SO 2 F) -OCF 2} CF 2 SO 2 F), by copolymerizing the proportion of each monomer unit a: 82.6mol%, B: 7.8mol %, C: 9.6mol% A sulfonic acid type perfluorocarbon polymer precursor was obtained. This precursor is hydrolyzed and acidified to convert it to an ion exchange resin having an ion exchange capacity of 1.52 meq / g dry resin, and then a mixture of the ion exchange resin in water and ethanol is used. A solution (solid content concentration of 10% by mass) was prepared as a solvent. Then, a solution of cerium nitrate dissolved in distilled water is added to this solution, and a solution of a resin in which 10% of the sulfonic acid groups in the ion exchange resin are ion exchanged with Ce ³⁺ (hereinafter referred to as ion exchange resin (A)). Got. This solution is cast on a fluororesin (trade name: Film Aflex) product number 100N (thickness: 100 μm) manufactured by Asahi Glass Co., Ltd. by die coating, and then dried at 80 ° C. for 15 minutes, and consists of the ion exchange resin (A). A fluororesin film intermediate having a thickness of 25 μm was obtained.
The obtained fluororesin film intermediate was exposed to ethanol saturated steam at 25 ° C. for 16 hours to obtain a swollen body. Next, the swollen body was annealed at 160 ° C. for 30 minutes to obtain a fluororesin film as a final molded body.

[Comparative Example 4]
A fluororesin film was obtained in the same manner as in Example 3 except that the exposure time to the ethanol saturated vapor was 1 hour.

[Comparative Example 5]
A fluorine-containing resin film was obtained in the same manner as in Example 3 except that the exposure to ethanol saturated vapor was not performed.

[Comparative Example 6]
Instead of exposure to ethanol saturated steam, ethanol was applied by die coating so that the amount of ethanol impregnation of the fluororesin film was 550 parts by mass with respect to 100 parts by mass of the fluororesin in the fluororesin film intermediate. Except for the above, a fluororesin film was obtained in the same manner as in Example 3. In Comparative Example 6, since the fluorine-containing resin swelled too much, a part of the fluorine-containing resin film was peeled off from the substrate, and a flat fluorine-containing resin film could not be obtained.

  The moisture content of the fluororesin films of Example 3 and Comparative Examples 4 and 5 and the amount of ethanol impregnation after exposure were determined. The moisture content was measured in the same manner as in Example 1, and the evaluation results were displayed assuming that the moisture content in Example 3 was 100. It shows that mechanical strength and dimensional stability are so favorable that a numerical value is small. The obtained results are shown in Table 2 below.

  From Table 2, Example 3 is mechanically compared with Comparative Examples 4 and 5 in which annealing conditions are the same by impregnating 50 parts by mass of ethanol with respect to 100 parts by mass of the fluororesin in the fluororesin intermediate. It was found that a fluorine-containing resin molded article excellent in strength and dimensional stability can be obtained. In Comparative Example 4, since the amount of ethanol impregnated in the intermediate of the fluororesin molded product is too small, ethanol is volatilized before the effect of promoting the annealing is obtained, and the effect of improving the mechanical strength and dimensional stability is observed. I couldn't.

Claims (9)

The following steps a) and b),
a) molding a fluororesin that is an electrolyte polymer or a mixture containing the fluororesin to obtain a fluororesin molded article intermediate;
b) impregnating 25 to 500 parts by mass of a good solvent with respect to 100 parts by mass of the fluororesin in the obtained fluororesin molded product intermediate, and annealing at 120 to 200 ° C ;
A process for producing a fluorine-containing resin molded article, comprising:   The method for producing a fluorinated resin molded article according to claim 1, wherein the fluorinated resin molded article is a fluorinated resin film.   The method for producing a fluorine-containing resin molded article according to claim 1, wherein the fluorine-containing resin molded article is a layered molded article having the fluorine-containing resin as a constituent element. 2. The step a) is a step in which a coating liquid containing a fluorine-containing resin or a mixture containing the fluorine-containing resin is applied to a substrate and then dried to obtain the fluorine-containing resin molded product intermediate. The manufacturing method of the fluorine-containing resin molding as described in any one of Claims 1-3 . The method for producing a fluororesin molded article according to claim 4 , wherein the coating liquid is a suspension, a dispersion or a solution. The step b) is a step of impregnating the good solvent by casting on the fluororesin molded product intermediate. 6. The fluororesin molded product according to any one of claims 1 to 5 . Production method. The method for producing a fluorinated resin molded product according to any one of claims 1 to 5 , wherein the step b) is a step of impregnating the fluorinated resin molded product intermediate by immersing it in the good solvent. . The method for producing a fluorinated resin molded product according to any one of claims 1 to 5 , wherein the step b) is a step of impregnating the fluorinated resin molded product intermediate by exposing it to the vapor of the solvent. . The good solvent is a fluorine-containing compound, an alcohol, One any one of claims 1-8 which is one, or a solvent mixture of two or more selected from the group consisting of glycol ethers and aromatic hydrocarbons The manufacturing method of the fluororesin molded object of description.