JP2023042231A - Steam permselective membrane, production method of steam permselective membrane, and on-vehicle lamp - Google Patents

Abstract

To provide a steam permselective membrane excellent in membrane strength and moisture permeability and hardly coming off an adhesion object, a production method thereof, and an on-vehicle lamp having the steam permselective membrane.SOLUTION: A steam permselective membrane P1 comprises a laminate including a steam permselective layer 2 containing a fluorine-containing polymer having an ion-exchange group and a nonwoven fabric layer 3 contacting the steam permselective layer 2 and containing a nonwoven fabric. In a production method of the steam permselective membrane, a coating layer is formed by coating the surface of the steam permselective layer containing a fluorine-containing polymer having an ion-exchange group with a polymer solution containing an adhesive polymer and a solvent, then the nonwoven fabric is laminated on the surface of the coating layer, and the solvent contained in the coating layer is removed. An on-vehicle lamp has the steam permselective membrane.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a selective water vapor permeable membrane, a method for producing a selective water vapor permeable membrane, and an in-vehicle lamp.

Fluoropolymers are sometimes used as water vapor permeable materials. For example, in US Pat. No. 5,400,000, it is proposed to cover the vent openings in the vehicle front lamp housing with an expanded polytetrafluoroethylene membrane of microporous material. However, this expanded polytetrafluoroethylene film has insufficient film strength.
Therefore, Patent Document 2 proposes a water vapor selective permeable membrane comprising a composite of a perfluorocarbon polymer having a sulfonic acid group and a woven fabric.

Japanese translation of PCT publication No. 2002-513504 JP 2005-111415 A

However, fluoropolymers having ion-exchange groups such as sulfonic acid groups swell when wet and shrink when dried, resulting in poor dimensional stability. When the selective water vapor permeable membrane of Patent Literature 2 is applied to dehumidification and humidification applications, repeated expansion and contraction of the membrane results in the problem that the membrane is easily peeled off from the adhered object.
Therefore, in the water vapor selective permeable membrane of Patent Document 2, sufficient membrane strength and resistance to peeling from the adhered object cannot be achieved at the same time.
In addition, the water vapor selective permeable membrane is required to have excellent moisture permeability.

The present invention provides a selective water vapor permeable membrane that is excellent in film strength and moisture permeability and is difficult to peel off from an object to which it is attached, a method for producing the same, and a vehicle lamp that includes the selective water vapor permeable membrane.

The present invention has the following aspects.
[1] A laminate comprising: a water vapor selective permeable layer containing a fluorine-containing polymer having an ion exchange group; and a nonwoven fabric layer in contact with the water vapor selective permeable layer and containing a nonwoven fabric. Water vapor selective permeable membrane.
[2] The selective water vapor permeation membrane of [1], wherein the nonwoven fabric layer has an adhesive layer containing an adhesive polymer in the voids in the nonwoven fabric, and the adhesive layer is in contact with the selective water vapor permeation layer.
[3] The water vapor selective permeation membrane of [2], wherein the nonwoven fabric layer further has an outer layer containing no adhesive polymer in the voids in the nonwoven fabric.
[4] A layer containing a nonwoven fabric is included inside the water vapor selective permeable layer containing a fluoropolymer having an ion exchange group, and the voids in the nonwoven fabric are filled with the fluoropolymer. A water vapor permselective membrane, characterized in that:
[5] The water vapor selective permeability of [4], wherein at least one surface of the water vapor selective permeability layer has either or both of an outer layer made of a nonwoven fabric and an outer layer containing the fluorine-containing polymer in the voids in the nonwoven fabric. film.
[6] The water vapor selective permeation membrane according to any one of [1] to [5], wherein the fluorine-containing polymer contains units represented by the following formula 1.
-[CF ₂ -CF(-L-(SO ₃ M) _n )]- Formula 1
In Formula 1, L is an n+1 valent perfluorohydrocarbon group which may contain an etheric oxygen atom, n is 1 or 2, and M is a hydrogen atom or an alkali metal.
[7] The selective water vapor permeable membrane according to any one of [1] to [6], further comprising an adhesive layer on at least one surface of the selective water vapor permeable membrane.
[8] The water vapor selective permeation membrane of any one of [1] to [7], wherein the nonwoven fabric contains at least one selected from the group consisting of natural fibers, chemical fibers and carbon fibers.
[9] A polymer solution containing an adhesive polymer and a solvent is applied to the surface of a water vapor selective permeable layer containing a fluorine-containing polymer having an ion exchange group to form a coating layer, and then a coating layer is formed on the surface of the coating layer. A method for producing a selective water vapor permeable membrane, comprising laminating a nonwoven fabric and removing the solvent contained in the coating layer.
[10] The production method of [9], wherein the fluorine-containing polymer contains a unit represented by formula 1 below.
-[CF ₂ -CF(-L-(SO ₃ M) _n )]- Formula 1
In Formula 1, L is an n+1 valent perfluorohydrocarbon group which may contain an etheric oxygen atom, n is 1 or 2, and M is a hydrogen atom or an alkali metal.
[11] The production method of [9] or [10], wherein the solvent in the polymer solution dissolves both the fluorine-containing polymer and the adhesive polymer.
[12] The production method according to any one of [9] to [11], wherein an adhesive layer is further provided on at least one surface of the water vapor selective permeable membrane.
[13] The production method according to any one of [9] to [12], wherein the nonwoven fabric contains at least one selected from the group consisting of natural fibers, chemical fibers and carbon fibers.
[14] A housing containing a lamp light source; and a water vapor selective permeable membrane closing an opening formed in the housing; A car lamp, which is a permselective membrane.

INDUSTRIAL APPLICABILITY According to the present invention, there are provided a water vapor selective permeable film that is excellent in film strength and moisture permeability and is difficult to peel off from an object to which it is attached, a method for producing the same, and an in-vehicle lamp provided with the water vapor selective permeable film.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view schematically showing an example of a water vapor selective permeable membrane according to the first aspect of the present invention; FIG. 4 is a cross-sectional view schematically showing another example of the water vapor selective permeable membrane according to the first aspect of the present invention. FIG. 4 is a cross-sectional view schematically showing another example of the water vapor selective permeable membrane according to the first aspect of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a water vapor selective permeable membrane according to a second aspect of the present invention; FIG. 4 is a cross-sectional view schematically showing another example of the water vapor selective permeable membrane according to the second aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically an example of the manufacturing method of the water vapor selective permeation membrane of this invention. 1 is a schematic diagram of an example of an in-vehicle lamp according to an embodiment; FIG. It is a figure which shows the result of having measured the water-vapor-permeability in each example.

The terms used herein have the following meanings.
A "unit" in a polymer means an atomic group derived from one molecule of a monomer formed by polymerizing the monomer. The unit may be an atomic group directly formed by the polymerization reaction, or may be an atomic group in which a part of the atomic group is converted to another structure by treating the polymer obtained by the polymerization reaction. . Units based on monomers are simply referred to as "monomer units".
A "sulfonic acid-type functional group" means a sulfonic acid group (--SO ₃ H) or a sulfonic acid group (--SO ₃ M, where M is an alkali metal).
"Water vapor permeability" is determined by the method described in Examples.
In this specification, the unit represented by formula 1 is referred to as unit 1. Units represented by other formulas are similarly described.

<Water vapor selective permeable membrane>
The water vapor selective permeable membrane of the present invention includes at least a water vapor selective permeable membrane P according to the first aspect below and a water vapor selective permeable membrane Q according to the second aspect below.
- Water vapor selective permeable membrane P according to the first aspect: a water vapor selective permeable layer containing a fluorine-containing polymer having ion exchange groups; and a nonwoven fabric layer in contact with the water vapor selective permeable layer and containing a nonwoven fabric A water vapor selective permeable membrane characterized by comprising a laminate comprising:
Selective water vapor permeable membrane Q according to the second aspect: A layer containing a nonwoven fabric is included inside the selective water vapor permeable layer containing a fluorine-containing polymer having an ion-exchange group, and the voids in the nonwoven fabric include A water vapor selective permeable membrane characterized by being filled with the fluorine-containing polymer.

Hereinafter, an example of the selective water vapor permeable membrane P according to the first aspect and an example of the selective water vapor permeable membrane Q according to the second aspect will be described in order with reference to the drawings. These embodiment examples are merely examples, and the water vapor selective permeable membrane of the present invention is not limited to these examples.
The dimensional ratios in FIGS. 1 to 7 are for convenience of explanation and are different from the actual ones. Moreover, in the drawings below, the same configuration may be indicated using the same words and symbols, and the description of overlapping configurations may be omitted.

(Water vapor selective permeable membrane P according to the first aspect)
FIG. 1 is a cross-sectional view schematically showing an example of the water vapor selective permeable membrane P according to the first aspect of the present invention. The water vapor selective permeable membrane P1 is a laminate comprising: a water vapor selective permeable layer 2 containing a fluorine-containing polymer having an ion exchange group; Become.

The water vapor selective permeable layer 2 contains a fluorine-containing polymer having ion exchange groups (hereinafter referred to as "fluorine-containing polymer I"). Since the water vapor selective permeable layer 2 contains the fluorine-containing polymer I, water vapor can selectively permeate from the high water vapor concentration to the low water vapor concentration.
Here, the content of the fluorine-containing polymer I in the water vapor selective permeability layer 2 is not particularly limited as long as the water vapor selective permeability is exhibited. Although the water vapor selective permeable layer 2 may further contain components other than the fluoropolymer I, it is preferably a layer composed of the fluoropolymer I.

In the fluorine-containing polymer I, the ion exchange group is not particularly limited. Examples include sulfonic acid groups, sulfonimide groups, sulfonemethide groups, phosphonic acid groups, carboxylic acid groups, ketoimide groups, and bases thereof.
Among them, a sulfonic acid group, a sulfonimide group, a sulfonemethide group and their bases are preferable, a sulfonic acid group, a sulfonimide group and their bases are more preferable, and a sulfonic acid group and a sulfonate group are more preferable.

The fluorine-containing polymer I preferably contains units 1 from the viewpoint of water vapor selective permeation performance, moisture permeability and mechanical properties.
-[CF ₂ -CF(-L-(SO ₃ M) _n )]- Formula 1
In Formula 1, L is an n+1 valent perfluorohydrocarbon group which may contain an etheric oxygen atom, n is 1 or 2, and M is a hydrogen atom or an alkali metal.

In Formula 1, when the n+1 valent perfluorohydrocarbon group contains an etheric oxygen atom, the oxygen atom may be located at the end of the perfluorohydrocarbon group or may be located between carbon atoms. . The number of carbon atoms in the n+1-valent perfluorohydrocarbon group is preferably 1 or more, more preferably 2 or more, preferably 20 or less, and more preferably 10 or less.

L is preferably an n+1 valent perfluoroaliphatic hydrocarbon group which may contain an etheric oxygen atom, and a divalent perfluoroalkylene group which may contain an etheric oxygen atom (n = 1 embodiment ), and a trivalent perfluoroaliphatic hydrocarbon group which may contain an etheric oxygen atom (embodiment where n=2) are more preferred.
A divalent perfluoroalkylene group may be linear or branched.

As the unit 1, for example, the following units 1-1, 1-2 and 1-3 are preferable.
-[CF ₂ -CF(-OR ^f1 -SO ₃ M)]- Formula 1-1
-[CF ₂ -CF(-R ^f1 -SO ₃ M)]- Formula 1-2

In formulas 1-1 to 1-3, R ^f1 is a perfluoroalkylene group which may contain an etheric oxygen atom between carbon atoms, and M is the same as in formula 1 above.
In formula 1-3, m is 0 or 1, and R ^f2 is a single bond or a perfluoroalkylene group optionally containing an etheric oxygen atom between carbon atoms.
The number of carbon atoms in the perfluoroalkylene group in R ^f1 and R ^f2 is preferably 1 or more, more preferably 2 or more, preferably 20 or less, and more preferably 10 or less. When the perfluoroalkylene groups of R ^f1 and R ^f2 contain etheric oxygen atoms, the number of such oxygen atoms may be one or two or more.

The unit 1-1 includes, for example, the following units 1-1-1, 1-1-2 and 1-1-3.
-[CF ₂ -CF(-O-(CF ₂ ) _w -SO ₃ M)]- Formula 1-1-1
-[CF ₂ -CF(-O-CF ₂ CF(CF ₃ )-O-(CF ₂ ) _w -SO ₃ M)]- Formula 1-1-2
-[CF ₂ -CF(-(O-CF ₂ CF(CF ₃ )) _x -SO ₃ M)]- Formula 1-1-3
w is an integer of 1 to 8, x is an integer of 1 to 5, and M is the same as in Formula 1 above.

Examples of the unit 1-2 include the following units 1-2-1 and 1-2-2.
-[CF ₂ -CF(-(CF ₂ ) _w -SO ₃ M)]- Formula 1-2-1
-[CF ₂ -CF(-CF ₂ -O-(CF ₂ ) _w -SO ₃ M)]- Formula 1-2-2
w is an integer of 1 to 8, and M is the same as in Formula 1 above.

As the unit 1-3, the unit 1-3-1 is preferable.

In formula 1-3-1, R ^f3 is a straight-chain perfluoroalkylene group having 1 to 6 carbon atoms, and R ^f4 is a single bond or a carbon number that may contain an etheric oxygen atom between carbon atoms. It is a linear perfluoroalkylene group of 1 to 6, M is the same as in formula 1 above, and m is the same as in formula 1-3 above.

In formula 1-3-1, R ^f4 is preferably a perfluoroalkylene group containing an etheric oxygen atom between carbon atoms. If R ^f4 is a perfluoroalkylene group containing an etheric oxygen atom, the flexibility of the fluorine-containing polymer I having the units 1-3-1 is improved. The water vapor selective permeable layer 2 containing the highly flexible fluorine-containing polymer I is resistant to breakage even when repeatedly swollen in a wet state and shrunk in a dry state, and tends to have good durability. In addition, the difference between the elastic modulus in the wet state and the elastic modulus in the dry state tends to be small, and cracks caused by wrinkles caused by repeated swelling in the wet state and shrinkage in the dry state are less likely to develop.

Units 1-3 include, for example, the following units.

From the viewpoint of mechanical properties, the fluorine-containing polymer I is a perfluorocarbon containing units 1 and units based on tetrafluoroethylene (hereinafter referred to as "TFE") (hereinafter also referred to as "TFE units"). Polymers are preferred.
However, the fluoropolymer I may further contain units derived from monomers other than the units 1 and TFE units (hereinafter also referred to as "other units").
Other monomers include, for example, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, ethylene, propylene, perfluoro α-olefins (hexafluoropropylene, etc.), (perfluoroalkyl)ethylene (perfluorobutyl)ethylene etc.), (perfluoroalkyl)propene (3-perfluorooctyl-1-propene, etc.), perfluorovinyl ether (perfluoro (alkyl vinyl ether), perfluoro (etheric oxygen atom-containing alkyl vinyl ether), etc.), International Publication No. 2011/013578 Examples include perfluoromonomers having a five-membered ring as described.
The fluoropolymer I may have one type each of the unit 1 and other units, or may have two or more types of each.

The ion exchange capacity of the fluorine-containing polymer I is preferably 0.8 to 2.00 meq/g, more preferably 0.9 to 1.90 meq/g. When the ion exchange capacity is at least the lower limit of the above range, the water vapor permeability is further improved, and the moisture permeability is further improved. If the ion exchange capacity is equal to or less than the upper limit of the above range, it is easy to synthesize a polymer having a high molecular weight, and swelling of the fluorine-containing polymer I is easily suppressed, so that the mechanical strength is further excellent and the dimensional stability is also improved. improves.

The ratio of each unit may be appropriately set according to the water vapor selective permeability (water vapor permeability), mechanical properties, ion exchange capacity, etc. required for the water vapor selective permeable membrane. For example, the higher the proportion of unit 1, the higher the ion exchange capacity and the more excellent water vapor selective permeability (water vapor permeability). Also, the higher the proportion of TFE units, the higher the film strength and the more excellent the mechanical properties.

The proportion of unit 1 is preferably 17.4 to 36.5 mol%, more preferably 18.1 to 29.9 mol%, out of 100 mol% of all structural units contained in the fluoropolymer I. 7 to 28.2 mol % is more preferable. If the proportion of unit 1 is at least the lower limit of the above range, the water vapor selective permeability (water vapor permeability) of the water vapor selective permeable membrane is further improved. If the proportion of unit 1 is equal to or less than the upper limit of the above range, the effects of structural units other than unit 1 are less likely to be inhibited.

The proportion of TFE units is preferably 63.5 to 82.6 mol%, more preferably 70.1 to 81.9 mol%, based on 100 mol% of all structural units contained in the fluorine-containing polymer I. 8 to 81.3 mol % is more preferable. If the proportion of TFE units is at least the lower limit of the above range, the mechanical properties of the water vapor selective permeable membrane are further improved. If the proportion of the TFE unit is equal to or less than the upper limit of the above range, the effect of structural units other than the TFE unit is less likely to be inhibited.

The total ratio of the other units is preferably 0 to 19.1 mol%, more preferably 0 to 11.8 mol%, more preferably 0 to 9, based on 100 mol% of all structural units contained in the fluorine-containing polymer I. 0.5 mol % is more preferred. If the total ratio of the other units is equal to or less than the upper limit of the above range, the effects of the unit 1 and the TFE unit are less likely to be inhibited.

The method for synthesizing the fluoropolymer I is not particularly limited. The fluoropolymer I can be synthesized by a known method as disclosed, for example, in International Publication No. 2017/221840.

The fluorine-containing polymer I of the water vapor selective permeable layer 2 may be of one type or two or more types. Moreover, the water vapor selective permeable layer 2 may further contain components other than the fluorine-containing polymer I as long as the effects of the invention are not impaired.

As the selective water vapor permeable layer 2, a non-porous selective water vapor permeable layer is preferable.
For example, if a conventional microporous film, such as the expanded polytetrafluoroethylene film of Patent Document 1, is used to block the opening of the housing of an in-vehicle lamp, foreign matter such as dust will enter the housing. In addition, the micropores may be clogged with foreign matter such as dust, and the water vapor permeation performance may be remarkably lowered. In addition, water may enter the housing during high-pressure washing of the vehicle, causing dripping of the on-vehicle lamp.
On the other hand, when the water vapor selective permeation layer is non-porous, when the opening of the housing is closed with the water vapor selective permeable membrane, it is difficult for foreign matter to enter the housing, and the water vapor permeability due to clogging is reduced. There is no decrease in the water content, and the contamination of water during high-pressure washing of the car is also reduced.

The thickness of the water vapor selective permeable layer 2 is preferably 5 to 50 μm, more preferably 10 to 40 μm, even more preferably 15 to 25 μm.
When the thickness of the selective water vapor permeation layer 2 is equal to or greater than the lower limit of the numerical range, pinholes are less likely to occur, and the selective water vapor permeation layer 2 can be easily formed as a non-porous film. When the thickness of the selective water vapor permeable layer is equal to or less than the upper limit value of the above numerical range, the selective water vapor permeable membrane is more difficult to peel off from the adhered object.

The nonwoven fabric layer 3 is in contact with the water vapor selective permeable layer 2 . Therefore, the nonwoven fabric constituting the nonwoven fabric layer 3 can follow the dimensional change caused by the expansion and contraction of the selective water vapor permeable layer 2 .
The nonwoven fabric layer 3 has an adhesive layer 31 containing an adhesive polymer in the voids within the nonwoven fabric. The adhesive layer 31 is in contact with the water vapor selective permeable layer 2 at the adhesive surface 31a. The adhesive layer 31 contributes to improving the adhesive strength between the nonwoven fabric layer 3 and the water vapor selective permeable layer 2 .

The adhesive polymer is not particularly limited as long as it can adhere the nonwoven fabric constituting the nonwoven fabric layer 3 to the water vapor selective permeable layer 2 . Therefore, the adhesive polymer can be selected from any polymer so that the peel strength between the adhesive layer 31 and the selective water vapor permeable layer 2 is practically sufficient.

Depending on the bonding mechanism between the water vapor selective permeable layer 2 and the nonwoven fabric, examples of adhesive polymers include the following adhesive polymers X1 to X3.
Adhesive polymer X1: A polymer that is soluble in the solvent Y that dissolves the fluorine-containing polymer I of the water vapor permselective layer 2 .
Adhesive polymer X2: A polymer having a polar group that interacts with the molecular chain of the fluorine-containing polymer I of the permselective water vapor layer 2 .
- Adhesive polymer X3: A polymer having a reactive group that chemically reacts with the fluorine-containing polymer I of the water vapor selective permeable layer 2 to form a covalent bond or an ionic bond (excluding the adhesive polymer X2).

The adhesive polymer X1 is soluble in the solvent Y that dissolves the fluorine-containing polymer I of the water vapor permselective layer 2 . Therefore, a polymer solution in which the adhesive polymer X1 is dissolved in the solvent Y can be prepared during production. By coating the surface of the selective water vapor permeable layer 2 with this polymer solution, the fluorine-containing polymer I on the surface of the selective water vapor permeable layer 2 can be partially dissolved. After that, the surface of the water vapor selective permeable layer 2 and the adhesive polymer X1 are welded and integrated, so that the nonwoven fabric and the water vapor selective permeable layer 2 can be adhered.

The solvent Y is not particularly limited as long as the amount of the fluorine-containing polymer I dissolved in 100 g of the solvent Y at 25° C. is 5 g or more. For example, acetone, methanol, 2-methoxyethanol, ethanol, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, 1,1,2-trichloroethane, 1,1,2, 2-tetrachloroethane, triethyl phosphate, tetrahydrofuran and the like.
These may be used individually by 1 type, and may use 2 or more types together.

The adhesive polymer X1 may be the fluorine-containing polymer I, or may be a polymer other than the fluorine-containing polymer I. When the adhesive polymer X1 is a fluoropolymer I, the adhesive polymer X1 may be the same fluoropolymer I as the fluoropolymer I in the water vapor permselective layer 2, or a different fluoropolymer I may be However, in terms of adhesion between the selective water vapor permeable layer 2 and the non-woven fabric layer 3, the adhesive polymer X1 is preferably the same type of fluorine-containing polymer I as the fluorine-containing polymer I in the selective water vapor permeable layer 2. .

When the adhesive polymer X1 is a polymer other than the fluoropolymer I, the adhesive polymer X1 is not particularly limited as long as it is soluble in the solvent Y that dissolves the fluoropolymer I of the water vapor selective permeable layer 2. However, even if swelling in a wet state and shrinking in a dry state are repeated, the linear expansion coefficient of the adhesive polymer X1 other than the fluorine-containing polymer I is the It is preferably about the same as the coefficient of linear expansion of polymer I.

The adhesive polymer X2 has a polar group that interacts with the molecular chains of the fluorine-containing polymer I of the permselective water vapor layer 2 . Therefore, van der Waals forces act between the polar groups in the adhesive polymer X2 and the molecular chains in the fluorine-containing polymer I, and the nonwoven fabric and the water vapor selective permeation layer 2 can be bonded.

Polar groups in the adhesive polymer X2 include, for example, carbonyl group-containing groups, hydroxy groups, epoxy groups, isocyanate groups and the like. The carbonyl group-containing group includes, for example, a group having a carbonyl group between carbon atoms of a hydrocarbon group, a carbonate group, a carboxy group, a haloformyl group, an alkoxycarbonyl group, an acid anhydride group, and the like.

Examples of the hydrocarbon group in the group having a carbonyl group between carbon atoms of the hydrocarbon group include an alkylene group having 2 to 8 carbon atoms. Here, the number of carbon atoms in the alkylene group is the number of carbon atoms in the state not including the carbon atoms that constitute the carbonyl group. The alkylene group may be linear or branched.
A haloformyl group is represented by -C(=O)-X (where X is a halogen atom). The halogen atom in the haloformyl group includes a fluorine atom, a chlorine atom and the like, and a fluorine atom is preferred. That is, the haloformyl group is preferably a fluoroformyl group (also referred to as a carbonyl fluoride group).
The alkoxy group in the alkoxycarbonyl group may be linear or branched. As the alkoxy group in the alkoxycarbonyl group, an alkoxy group having 1 to 8 carbon atoms is preferable, and a methoxy group or an ethoxy group is particularly preferable.

The adhesive polymer X3 has a reactive group that chemically reacts with the fluorine-containing polymer I of the permselective water vapor layer 2 to form a covalent bond or an ionic bond. The reactive group may be any group capable of reacting with the ion-exchange group of the fluorine-containing polymer I. For example, when the fluorine-containing polymer I has a sulfonic acid group or the like, the reactive group in the adhesive polymer X3 may be a group capable of reacting with the sulfonic acid group.

One of the adhesive polymers X1 to X3 may be used alone, or two or more of them may be used in combination.
Moreover, a polymer corresponding to the adhesive polymer X1 may exist among the adhesive polymer X2 and the adhesive polymer X3. When using the adhesive polymer X2 and the adhesive polymer X3, which also correspond to the adhesive polymer X1, in addition to the adhesive mechanism as the adhesive polymer X1, the adhesive mechanism as the adhesive polymer X2 and the adhesive polymer X3 It is conceivable that each of the adhesion mechanisms may be obtained in a superimposed manner.

The adhesive layer 31 contains an adhesive polymer so that voids between fibers of the nonwoven fabric remain. That is, voids exist sparsely throughout the adhesive layer 31 in the nonwoven fabric of the adhesive layer 31 . Depending on the adhesion mechanism of the adhesive polymer and the material of the fibers of the nonwoven fabric, it is believed that the adhesive polymer exists on the surface of the fibers and inside the fibers in the voids in the nonwoven fabric.

In the water vapor selective permeable membrane P1, the nonwoven fabric layer 3 further has an outer layer 32 containing no adhesive polymer in the voids within the nonwoven fabric. The outer layer 32 is provided on the surface 31b of the adhesive layer 31 opposite to the adhesive surface 31a in the thickness direction.
In the outer layer 32, all the voids of the nonwoven fabric before bonding remain intact. Therefore, it can also be said that the outer layer 32 is a layer made of nonwoven fabric.

The nonwoven fabric forming the outer layer 32 may be a nonwoven fabric integral with the nonwoven fabric forming the adhesive layer 31 or may be a nonwoven fabric separate from the nonwoven fabric forming the adhesive layer 31 and separable. When the outer layer 32 is a nonwoven fabric integral with the nonwoven fabric that constitutes the adhesive layer 31, a part of the nonwoven fabric in the thickness direction before bonding constitutes the adhesive layer 31, and the rest in the thickness direction is the outer layer 32 as it is. configure.
When the outer layer 32 is a nonwoven fabric separate from the nonwoven fabric that constitutes the adhesive layer 31, after bonding the selective water vapor permeable layer 2 and the nonwoven fabric to form only the adhesive layer 31, the adhesive layer 31 is formed on the surface of the adhesive layer 31. A different nonwoven fabric may be separately provided to form the outer layer 32 .

The thickness of the nonwoven fabric layer 3 is preferably 50 to 300 μm, more preferably 80 to 200 μm, even more preferably 100 to 150 μm.
If the thickness of the nonwoven fabric layer 3 is equal to or greater than the lower limit of the numerical range, the membrane strength of the selective water vapor permeable membrane is further improved. When the thickness of the nonwoven fabric layer 3 is equal to or less than the upper limit value of the above numerical range, the flexibility of the nonwoven fabric layer 3 is further excellent, and the dimensional change caused by the expansion and contraction of the selective water vapor permeable layer 2 can be easily followed.

The material of the fibers of the nonwoven fabric is not particularly limited. Examples thereof include nonwoven fabrics containing at least one selected from the group consisting of natural fibers, chemical fibers and carbon fibers.
The nonwoven fabric may be a nonwoven fabric made of one type of fiber, or a mixed nonwoven fabric made of a plurality of types of fibers.

Natural fibers may be plant-derived fibers or animal-derived fibers. Plant-derived fibers include, for example, cotton, kapok fiber, bamboo fiber, flax fiber, hemp fiber, pulp fiber, manila hemp fiber, and the like. Animal-derived fibers include, for example, wool, goat hair, horse hair, llama hair, and the like.
Chemical fibers include, for example, polyethylene terephthalate, polybutylene terephthalate, polyvinyl alcohol, polyamide, rayon, polyethylene, polypropylene, polyphenylene sulfide, polyacryl, and polyurethane. Among them, polyethylene terephthalate, polyvinyl alcohol, polyamide, rayon, polyethylene, polypropylene, polyacryl, and polyurethane are preferable from the viewpoint of cost performance.
Examples of carbon fibers include PAN (polyacrylonitrile)-based carbon fibers and pitch-based carbon fibers. A water vapor selective permeable membrane having excellent membrane strength can be obtained by using any carbon fiber.

Among these, when the fluorine-containing polymer I in the water vapor selective permeable layer 2 has strongly acidic ion exchange groups such as sulfonic acid groups, chemical fibers having excellent acid resistance are preferred. Chemical fibers having excellent acid resistance include polyethylene terephthalate, polybutylene terephthalate, rayon, polypropylene, and polyphenylene sulfide. When the nonwoven fabric contains these acid-resistant chemical fibers, the long-term strength stability is excellent even when the fluorine-containing polymer I has strongly acidic ion-exchange groups such as sulfonic acid groups.

The basis weight of the nonwoven fabric is preferably 5 to 120 g/m ² , more preferably 15 to 100 g/m ² , still more preferably 20 to 80 g/m ² .
If the weight per unit area of the fibers of the nonwoven fabric is at least the lower limit of the numerical range, the membrane strength of the selective water vapor permeation membrane will be even better. If the basis weight of the fibers of the nonwoven fabric is equal to or less than the upper limit of the numerical range, the softness of the nonwoven fabric is further improved.

The water vapor selective permeable membrane P1 can be manufactured, for example, by the method described in the section <Manufacturing method of water vapor selective permeable membrane> below.

Although the nonwoven fabric layer 3 has an adhesive layer 31 and an outer layer 32 in the example shown in FIG. 1, the water vapor selective permeable membrane P is not limited to this example. The water vapor selective permeable membrane P includes a form such as a water vapor selective permeable membrane P2 provided with a nonwoven fabric layer 3' consisting only of an adhesive layer 31, as in one example shown in FIG. The details and preferred aspects of the nonwoven fabric layer 3 ′ are the same as those described for the nonwoven fabric layer 3 .
The water vapor selective permeable membrane P2 can be manufactured, for example, by a casting method.

In addition to the examples shown in FIGS. 1 and 2, the selective water vapor permeable membrane P may be a selective water vapor permeable membrane P3 having a nonwoven fabric layer 3'' consisting only of an outer layer 32, such as an example shown in FIG. forms.
In the water vapor selective permeable membrane P3, the non-woven fabric layer 3'' consisting of only the outer layer 32 is in contact with the water vapor selective permeable layer 2. As shown in FIG. In the water vapor selective permeable membrane P3, it is considered that there is a very thin adhesive region at the interface between the outer layer 32 and the water vapor selective permeable layer 2, which cannot be called a layer.
The details and preferred aspects of the nonwoven fabric layer 3 ″ are also the same as those described for the nonwoven fabric layer 3 .
The water vapor selective permeable membrane P3 can be produced, for example, by hot-pressing the water vapor selective permeable layer 2 and a non-woven fabric.

Since the water vapor selective permeable membrane P according to the first aspect described above with some examples has a water vapor selective layer containing the fluorine-containing polymer I, it has excellent moisture permeability. Moreover, the water vapor selective permeable layer is in contact with the nonwoven fabric layer containing the nonwoven fabric. Therefore, the nonwoven fabric can function as a reinforcing material for the selective water vapor permeable layer, and the membrane strength of the selective water vapor permeable membrane P is improved.
In addition, nonwoven fabrics are more flexible than woven fabrics. Therefore, even if the selective water vapor permeable layer expands and contracts repeatedly when applied to dehumidification and humidification, the nonwoven fabric in contact with the selective water vapor permeable layer can follow the dimensional change of the selective water vapor permeable layer. As a result, the dimensional stability of the entire film is improved, the amount of movement on the adhesive surface with respect to the object to be applied is suppressed, and both sufficient film strength and resistance to peeling from the object to be applied can be achieved.
Therefore, the water vapor selective permeable membrane P is excellent in membrane strength and moisture permeability, and is difficult to peel off from the adhered object.

(Water vapor selective permeable membrane Q according to the second aspect)
The water vapor selective permeable membrane Q according to the second aspect of the present invention includes a layer containing a nonwoven fabric inside the water vapor selective permeable layer containing the fluorine-containing polymer I, and the voids in the nonwoven fabric contain the above-mentioned It is characterized by being filled with a fluorine-containing polymer.

FIG. 4 is a cross-sectional view schematically showing an example of the water vapor selective permeable membrane Q according to the second aspect of the present invention. The water vapor selective permeable membrane Q1 has a water vapor selective permeable layer 20 containing a fluorine-containing polymer I. As shown in FIG. Inside the water vapor selective permeable layer 20, a layer containing a non-woven fabric is included.

The fluoropolymer I is filled in the voids in the nonwoven fabric inside the water vapor selective permeable layer 20 . That is, the fluoropolymer I is filled between fibers in the nonwoven fabric inside the water vapor selective permeable layer 20, and voids do not exist in the nonwoven fabric. Therefore, the selective water vapor permeability layer 20 exhibits selective water vapor permeability and excellent moisture permeability.
The details and preferred aspects of the fluorine-containing polymer I and the nonwoven fabric are the same as those described for the water vapor selective permeation membrane P.

The thickness of the water vapor selective permeable layer 20 is preferably 50 to 300 μm, more preferably 80 to 200 μm, even more preferably 100 to 150 μm.
If the thickness of the water vapor selective permeable layer 2 is equal to or greater than the lower limit of the numerical range, the membrane strength is further improved. When the thickness of the selective water vapor permeable layer is equal to or less than the upper limit value of the above numerical range, the selective water vapor permeable membrane is more difficult to peel off from the adhered object.

In the example shown in FIG. 4, the selective water vapor permeable membrane Q1 is formed of the selective water vapor permeable layer 20. The selective water vapor permeable membrane Q is made of nonwoven fabric on at least one surface of the selective water vapor permeable layer. Either one or both of the outer layer and the outer layer containing the fluorine-containing polymer I in the voids in the nonwoven fabric may be provided.
In the outer layer containing the fluoropolymer I in the voids in the nonwoven fabric, the fluoropolymer I is contained so that the voids between the fibers of the nonwoven fabric remain. That is, in the outer layer containing the fluorine-containing polymer I in the voids in the nonwoven fabric, the voids in the nonwoven fabric exist sparsely throughout. Although it depends on the material of the fibers of the nonwoven fabric, it is considered that the fluoropolymer I is present on the surface of the fibers and inside the fibers in the voids in the nonwoven fabric.

The water vapor selective permeable membrane Q1 can be manufactured by, for example, a casting method. For example, it can be produced by applying a solution containing the fluorine-containing polymer I to the surface of the substrate to form a coating layer, and immersing the nonwoven fabric in the coating layer. At this time, the fluoropolymer I is filled in the voids in the nonwoven fabric. In order to reliably fill the voids in the nonwoven fabric with the fluoropolymer I, the operation of applying the solution containing the fluoropolymer I may be repeated multiple times.

In addition to the example shown in FIG. 4, the selective water vapor permeation membrane Q has an outer layer 32 made of non-woven fabric on one surface 20a of the selective water vapor permeable layer 20, as in the example shown in FIG. morphology such as membrane Q2. The outer layer 32 is the same as the description of the water vapor selective permeable membrane P.

In the water vapor selective permeable membrane Q according to the second aspect described above with several examples, the layer containing the nonwoven fabric is included inside the water vapor selective permeable layer 20, so the nonwoven fabric is used as the reinforcing material. and the membrane strength of the water vapor selective permeable membrane Q is improved. This nonwoven fabric is excellent in flexibility like the water vapor selective permeable membrane P according to the first aspect, and can follow the dimensional change of the water vapor selective permeable layer. Therefore, even if the selective water vapor permeation layer expands and contracts repeatedly when applied to dehumidification and humidification applications, the dimensional stability of the entire film is good, and the amount of movement on the adhesive surface with the adhered object is suppressed. . As a result, it is possible to achieve both sufficient film strength and resistance to peeling from the adhered object.
In addition, in the interior of the water vapor selective permeable layer containing the fluoropolymer I, the voids in the nonwoven fabric are filled with the fluoropolymer I, so the selective water vapor permeable membrane Q has excellent moisture permeability.
Therefore, the water vapor selective permeable membrane Q has excellent membrane strength and moisture permeability, and is difficult to peel off from the adhered object.

(Water vapor selective permeable membrane according to one embodiment)
Hereinafter, an embodiment including the water vapor selective permeable membrane P and the water vapor selective permeable membrane Q will be described as a water vapor selective permeable membrane according to one embodiment. That is, in the following description, the "selective water vapor permeable membrane according to one embodiment" includes the selective water vapor permeable membrane P and the selective water vapor permeable membrane Q.

The moisture permeability at 50% RH of the water vapor selective permeable membrane according to one embodiment is preferably 600 to 2500 g/m ² ·24h, more preferably 800 to 2000 g/m ² ·24h, and 1000 to 1400 g/m ² ·24h. is more preferred. If the moisture permeability at 50% RH is equal to or higher than the lower limit of the above range, it can be said that the selective water vapor permeable membrane has excellent moisture permeability in a high humidity environment. If the moisture permeability at 50% RH is equal to or lower than the upper limit of the above range, the selective water vapor permeable membrane is considered to be less likely to peel off from the adhered object even in a high humidity environment.

The water vapor selective permeable membrane according to one embodiment may further include an adhesive layer on at least one surface. The adhesive layer is an adhesive layer for adhering the water vapor selective permeable membrane to an object to be adhered. The surface on which the adhesive layer is provided may be determined in consideration of the application of the selective water vapor permeable membrane, the object to be adhered, and the desired water vapor permeation performance.
The adhesive layer may be partially provided on a part of the surface of the water vapor selective permeable membrane in plan view, or may be provided over the entire surface. For example, the adhesive layer may be provided on a portion of the surface of the selective water vapor permeable membrane along the outer edge of the selective water vapor permeable membrane.

The adhesive layer may be formed by applying an adhesive, or may be formed by treating the surface of the selective water vapor permeable membrane with a primer.
The adhesive is not particularly limited. For example, a pressure-sensitive adhesive containing an acrylic polymer can be used, but the present invention is not limited to this example. The pressure-sensitive adhesive may be selected from various pressure-sensitive adhesives in consideration of the application of the selective water vapor permeable membrane, the object to be adhered, and the desired water vapor permeation performance. In this case, the pressure-sensitive adhesive layer may further contain components other than the pressure-sensitive adhesive, depending on the use of the water vapor selective permeable membrane and the object to which it is attached.
The thickness of the adhesive layer is also not particularly limited, and may be determined according to the application, the object to be adhered, and the desired water vapor transmission performance. An adhesive tape may be used as the adhesive layer.

<Method for producing water vapor selective permeable membrane>
In the method for producing a selective water vapor permeable membrane of the present invention, a polymer solution containing an adhesive polymer and a solvent is applied to the surface of a selective water vapor permeable layer containing a fluorine-containing polymer I to form a coating layer, followed by the steps of: It is characterized by laminating a non-woven fabric on the surface of the coating layer and removing the solvent contained in the coating layer.
The details and preferred aspects of the fluorine-containing polymer I, the adhesive polymer and the non-woven fabric are the same as those described in the section <Selective Water Vapor Permeable Membrane>.

The polymer solution contains an adhesive polymer and a solvent. The solvent in the polymer solution preferably dissolves both the fluorine-containing polymer I and the adhesive polymer. That is, solvent Y is preferable as the solvent in the polymer solution. The details and preferred aspects of the solvent Y are the same as those described in the section <Water vapor selective permeable membrane>.
From the viewpoint of production cost, the adhesive polymer X1 is preferable, and the fluorine-containing polymer I is preferable as the adhesive polymer in the polymer solution.
The polymer solution may further contain components other than the adhesive polymer and the solvent as long as the effects of the invention are not impaired.

FIG. 6 is a cross-sectional view schematically showing an example of a method for producing a selective water vapor permeable membrane according to one embodiment.
In the example shown in FIG. 6, first, the water vapor selective permeable layer 2 provided on the substrate 7 is prepared in advance. The water vapor selective permeable layer 2 is provided on the surface of the substrate 7 by, for example, applying a solution of the fluorine-containing polymer I dissolved in the solvent Y to the surface of the substrate 7, followed by drying and solidification.

The substrate 7 is not particularly limited as long as it is a substrate film used in the casting method.
The material of the substrate is not particularly limited. Examples thereof include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyimide, etc., but are not limited to these examples. The substrate may be a single layer film or a multilayer film.

The amount of the solution applied to the surface of the substrate 7 is not particularly limited. It is preferable to adjust the thickness of the selective water vapor permeation layer 2 so that it falls within the preferable numerical range described in the section <Selective water vapor permeability membrane>.
Moreover, the thickness of the base material 7 is not specifically limited, either. Considering that the base material 7 serves as a release layer for protecting the water vapor selective permeation membrane during distribution and is peeled off during use, the thickness of the base material 7 (release layer) may be about 50 to 200 μm, and the thickness is about 75 to 75 μm. It may be about 125 μm.

Next, a coating layer 8 is formed by applying a polymer solution containing an adhesive polymer and a solvent to the surface of the water vapor selective permeable layer 2 . The thickness of the coating layer 8 is not particularly limited. For example, it is preferably 90-180 μm, more preferably 120-150 μm. When the thickness of the coating layer 8 is equal to or greater than the lower limit, the adhesive strength between the selective water vapor permeable layer 2 and the nonwoven fabric is likely to be improved. If the thickness of the coating layer 8 is equal to or less than the upper limit, the productivity is likely to be improved.

When the polymer solution contains the fluorine-containing polymer I, the fluorine-containing polymer I in the coating layer 8 may be of one type or two or more types. The fluorine-containing polymer I in the coating layer 8 may be the same type as or different from the fluorine-containing polymer I in the water vapor permselective layer 2 .

Next, the nonwoven fabric 30 is laminated on the surface of the coating layer 8, and the solvent contained in the coating layer 8 is removed.
By laminating the nonwoven fabric 30 on the surface of the coating layer 8 , the polymer solution of the coating layer 8 permeates into the nonwoven fabric, and the selective water vapor permeable layer 2 and the nonwoven fabric 30 are integrated. After that, by removing the solvent contained in the coating layer 8, the water vapor selective permeable layer 2 and the nonwoven fabric layer 3 are strongly bonded. At this time, some fibers of the nonwoven fabric 3 are impregnated with the adhesive polymer of the polymer solution.

When laminating the nonwoven fabric 30 on the surface of the coating layer 8, it may be laminated under pressure in order to increase the adhesive strength.
As a method for removing the solvent contained in the coating layer 8 after lamination of the nonwoven fabric 30, natural drying or heat drying may be used.

In the method for producing the selective water vapor permeable membrane of the present invention, an adhesive layer may be further provided on at least one surface of the selective water vapor permeable membrane. The details and preferred aspects of the adhesive layer are the same as those described in the section <Selective water vapor permeability membrane>.

(Mechanism of action)
In the method for producing a water vapor selective permeable membrane according to one embodiment described above, the surface of the water vapor selective permeable layer containing the fluoropolymer I is coated with a solution containing the fluoropolymer I, and then It is characterized by overlaying a nonwoven fabric on the surface of the coating layer of the solution containing. Therefore, the solution containing the fluorine-containing polymer permeates into the nonwoven fabric, and the nonwoven fabric having excellent flexibility is integrally adhered to the water vapor selective permeation layer.
As a result, when applied to dehumidification and humidification applications, the nonwoven fabric easily follows the dimensional changes of the water vapor selective permeable layer, the dimensional stability of the entire water vapor selective permeable membrane is improved, and the adhesive surface with the adhered object is improved. is suppressed. In addition, the nonwoven fabric contributes to improving the strength of the selective water vapor permeable membrane, and the selective water vapor permeable membrane contributes to improving the moisture permeability.
Therefore, according to the method for producing a selective water vapor permeable membrane according to one embodiment, it is possible to obtain a selective water vapor permeable membrane which is excellent in membrane strength and moisture permeability and which is difficult to peel off from an adhered object.

<Application>
A water vapor selective permeable membrane according to one embodiment is difficult to peel off from an adhered object even when used under conditions where swelling and expansion/contraction are frequently repeated. Therefore, the water vapor selective permeable membrane according to one embodiment can be applied, for example, to dehumidification or humidification of fluids.

One example of the application of the water vapor selective permeable membrane is the application for dehumidification or humidification of vehicle lamps. FIG. 7 is a schematic diagram of an example of an in-vehicle lamp according to an embodiment, showing an in-vehicle lamp 10 provided with a non-porous flat sheet water vapor selective permeable membrane 1 for dehumidification or humidification.
A vehicle-mounted lamp 10 includes a housing 11 containing a lamp light source (LED light) 13 and a socket 14; LED is an abbreviation for Light Emitting Diode.
According to the in-vehicle lamp 10, since the opening 12 of the housing 11 is covered with the water vapor selective permeable membrane 1, when there is a difference in humidity between the inside and outside of the housing 11, the water vapor D moves from the area with the higher concentration to the area with the lower concentration. D can be selectively transmitted.

The water vapor selective permeable membrane 1 is attached to the outer surface of the housing 11 . The selective water vapor permeable membrane 1 is arranged so that the selective water vapor permeable layer is located on the inner side of the housing 11 . Therefore, it is expected that the amount of moisture exchanged between the inside and outside of the housing 11 will increase.
In addition, the water vapor selective permeable membrane 1 is excellent in membrane strength and moisture permeability, and is difficult to peel off from the housing 11 even if expansion and contraction are repeated. As a result, it is expected that the long-term durability of the in-vehicle lamp 10 will be improved.

The material of the housing 11 is not particularly limited, but if it is a hygroscopic resin, the effect of the invention can be obtained remarkably. For example, if the material of the housing 11 is a hygroscopic resin such as an acrylic resin or a polycarbonate resin, the housing 11 absorbs moisture in the outside atmosphere, and the moisture is diffused and held in the hygroscopic resin. After that, when the housing 11 is heated by sunlight, a lamp, or the like, the moisture absorbed from the atmosphere evaporates, and the water vapor D diffuses within the housing 11 . Such water vapor D may cause fogging of the vehicle lamp 10, safety problems such as condensation, and appearance problems such as dripping inside the housing.
In order to deal with these problems, since the opening 12 of the housing 11 of the vehicle lamp 10 is covered with the water vapor selective permeable membrane 1, the amount of moisture exchanged between the inside and outside of the housing 11 is large. Therefore, when the humidity inside the housing 11 increases, the inside of the housing 11 is dehumidified by the water vapor selective permeable membrane 1 . As a result, fogging, condensation, and dripping of the in-vehicle lamp 10 are effectively suppressed.

The water vapor selective permeable membrane 1 is a non-porous flat membrane. Therefore, the water vapor selective permeable membrane 1 can also function as a dust-proof film for preventing foreign matter such as dust from entering the housing 11 . Since the water vapor selective permeable membrane 1 is a non-porous flat membrane, it is possible to reduce foreign matter such as dust entering the housing 11 . Also, water is less likely to enter the housing 11 during high-pressure washing of the vehicle.

In the vehicle lamp 10 , the water vapor selective permeable membrane 1 covers and blocks the opening 12 outside the housing 11 , but in other exemplary embodiments, the water vapor selective permeable membrane 1 is inside the housing 11 and closes the opening 12 . may be covered and blocked.
Also, the size and shape of the opening 12 are not particularly limited. In the vehicle lamp 10, the number of openings 12 is one, but in other example embodiments, the number of openings may be more than one.

The in-vehicle lamp 10 is an illustration as an example of an embodiment. Accordingly, an automotive lamp according to one embodiment may have various configurations not shown in FIG. For example, the housing of the vehicle lamp may be formed with a vent for adjusting the internal pressure.
Further, in the in-vehicle lamp 10 of FIG. 7, an LED light is used as an example of the lamp light source, but in other embodiments, the lamp light source may be a halogen light or an HID light. The lamp light source is not particularly limited as long as it is used as a vehicle light. HID is an abbreviation for High Intensity Discharge.
In addition, the in-vehicle lamp may include various configurations such as an attachment portion (connection terminal, etc.) for attachment to the vehicle, a control portion for controlling the operation of the in-vehicle lamp by the vehicle, and the like.

Although one embodiment has been described above, the present invention is not limited to the embodiments disclosed in this specification, and can be implemented with appropriate modifications without changing the gist thereof. The embodiments disclosed herein can be embodied in various other forms, and various omissions, substitutions, and modifications are possible without departing from the scope of the invention.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to the following descriptions. Example 1 is an example, and Examples 2 and 3 are comparative examples.

<Measurement method>
(moisture permeability)
The moisture permeability (g/m ² ·24 h) was measured according to the moisture permeability test method (cup method) specified in JIS Z 0208. Specifically, a moisture-impermeable measurement container was prepared, and about 23 g of calcium chloride was filled in the measurement container. The measuring vessel had a volume of 24 ml, a base area of 300 mm ² and a height of 80 mm. Calcium chloride was filled so that the height from the bottom of the measurement container was about 77 mm.
Next, a rectangular evaluation film was cut out so as to match the shape of the opening of the measurement container, fixed to the outer edge of the opening of the measurement container, and then the measurement container was placed on an electronic balance. After that, the measurement container together with the electronic balance was placed in a constant temperature machine at a temperature of 20° C. and 30% RH, and measurement of moisture permeability (g/m ² ·24 h) was started. The moisture permeability (g/m ² ·24h) of each film to be evaluated was obtained from the change in mass of calcium chloride. Specifically, the total average was calculated from 17 hours to 24 hours after the start of the measurement, and was taken as the moisture permeability (g/m ² ·24 hours).
Subsequently, the moisture permeability (g/m ² ·24 h) under each humidity condition was measured in the same manner except that the conditions of the constant temperature machine were changed to 50% RH and 80% RH.

<raw materials>
(Fluorine-containing polymer)
A commercially available Flemion FSS-2 (trade name, manufactured by AGC, ethanol solution) was used.

(non-woven fabric)
A non-woven fabric (manufactured by Nihon Vilene Co., Ltd.) having a thickness of about 130 μm was prepared by blending polyethylene and polypropylene.

<Example 1>
A PET film was coated with an ethanol solution of Flemion FSS-2 and dried to solidify the coating layer, thereby forming a water vapor selective permeation layer containing Flemion FSS-2 on the PET film. The thickness of the water vapor selective permeable layer provided on the PET film was 25 μm.
Thereafter, an ethanol solution of Flemion FSS-2 was applied to the surface of the water vapor selective permeable layer provided on the PET film to form a coating layer having a thickness of 120 μm. Then, before the ethanol solution of Flemion FSS-2 dried and solidified, a non-woven fabric was laminated on the surface of the coating layer, and the ethanol was removed by drying to obtain the water vapor selective permeable membrane of Example 1.
The obtained water vapor selective permeable membrane was cut into a 40 mm×20 mm square, and a double-faced tape was attached along the outer edge of the rectangular water vapor selective permeable membrane to measure moisture permeability.

<Example 2>
A stretched ETFE porous membrane (manufactured by Gore, trade name “Automotive Vent”) was used as an evaluation target membrane. The stretched ETFE porous membrane was cut into a square of 40 mm×20 mm, a double-faced tape was attached along the outer edge of the square stretched ETFE porous membrane, and the moisture permeability was measured.

<Example 3>
In Example 3, a PTFE porous membrane (manufactured by Nitto Denko Corporation, trade name "TEMISH") was used as a membrane to be evaluated. The PTFE porous membrane was cut into a square of 40 mm×20 mm, and a double-faced tape was attached along the outer edge of the square PTFE porous membrane to measure the moisture permeability.

FIG. 8 is a diagram showing results of measuring moisture permeability in each example. "Blank" in FIG. 8 indicates the measurement result of moisture permeability when no film was fixed to the opening of the measurement container. Therefore, the "blank" plot corresponds to the maximum value of water vapor transmission rate under each measurement condition.
As shown in FIG. 8, in Example 1, as the relative humidity of the surrounding environment increased, the difference from the maximum value of the moisture permeability indicated by the blank decreased compared to Examples 2 and 3. From this result, it was confirmed that excellent moisture permeability was exhibited in a high-humidity environment with a relative humidity of 50% or higher.

According to one embodiment, there are provided a water vapor selective permeable film that is excellent in film strength and moisture permeability and is difficult to peel off from an object to which it is attached, a method for manufacturing the same, and an in-vehicle lamp that includes the water vapor selective permeable film.

DESCRIPTION OF SYMBOLS 1... Water vapor selective permeable membrane, 2, 20... Water vapor selective permeable layer, 3... Nonwoven fabric layer, 7... Base material, 8... Coating layer, 10... Vehicle lamp, 11... Housing, 12... Opening, 13... Lamp Light source (LED light) 14 Socket 30 Non-woven fabric 31 Adhesive layer 32 Outer layer.

Claims (14)

a water vapor permselective layer containing a fluorine-containing polymer having ion exchange groups;
a nonwoven fabric layer in contact with the water vapor selective permeable layer and containing a nonwoven fabric;
A water vapor selective permeable membrane comprising a laminate comprising: the nonwoven fabric layer has an adhesive layer containing an adhesive polymer in the voids within the nonwoven fabric;
2. The water vapor selective permeable membrane according to claim 1, wherein the adhesive layer is in contact with the water vapor selective permeable layer. 3. The water vapor selective permeation membrane according to claim 2, wherein the nonwoven layer further has an outer layer that does not contain an adhesive polymer in the voids within the nonwoven. A layer containing a non-woven fabric is included inside a water vapor selective permeable layer containing a fluoropolymer having an ion-exchange group, and voids in the non-woven fabric are filled with the fluoropolymer. , water vapor permselective membrane. 5. The selective water vapor permeable membrane according to claim 4, wherein at least one surface of the water vapor selective permeable layer has either or both of an outer layer made of a nonwoven fabric and an outer layer containing the fluoropolymer in the voids in the nonwoven fabric. . The water vapor selective permeation membrane according to any one of claims 1 to 5, wherein the fluorine-containing polymer contains units represented by the following formula 1.
-[CF ₂ -CF(-L-(SO ₃ M) _n )]- Formula 1
In Formula 1, L is an n+1 valent perfluorohydrocarbon group which may contain an etheric oxygen atom, n is 1 or 2, and M is a hydrogen atom or an alkali metal. The selective water vapor permeable membrane according to any one of claims 1 to 6, further comprising an adhesive layer on at least one surface of the selective water vapor permeable membrane. The water vapor selective permeation membrane according to any one of claims 1 to 7, wherein the nonwoven fabric contains at least one selected from the group consisting of natural fibers, chemical fibers and carbon fibers. A polymer solution containing an adhesive polymer and a solvent is applied to the surface of a water vapor selective permeable layer containing a fluorine-containing polymer having an ion exchange group to form a coating layer, and then a nonwoven fabric is laminated on the surface of the coating layer. and removing the solvent contained in the coating layer. 10. The production method according to claim 9, wherein the fluorine-containing polymer contains units represented by the following formula 1.
-[CF ₂ -CF(-L-(SO ₃ M) _n )]- Formula 1
In Formula 1, L is an n+1 valent perfluorohydrocarbon group which may contain an etheric oxygen atom, n is 1 or 2, and M is a hydrogen atom or an alkali metal. The production method according to claim 9 or 10, wherein the solvent in the polymer solution dissolves both the fluorine-containing polymer and the adhesive polymer. The production method according to any one of claims 9 to 11, further comprising an adhesive layer provided on at least one surface of the water vapor selective permeable membrane. The manufacturing method according to any one of claims 9 to 12, wherein the nonwoven fabric contains at least one selected from the group consisting of natural fibers, chemical fibers and carbon fibers. a housing containing a lamp light source;
a water vapor selective permeable membrane closing an opening formed in the housing;
with
A vehicle-mounted lamp, wherein the water vapor selective permeable membrane is the water vapor selective permeable membrane according to any one of claims 1 to 8.

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