JP2016089023A - Method for producing water repellent film - Google Patents

Abstract

Provided is a method for producing a water-repellent film, which can be easily carried out and can produce a highly durable water-repellent film. A bonding step of bonding a first surface of a first base film and a first surface of a second base film through a bonding material to obtain a laminate, and the first Including a peeling step of peeling the base film of 1 and the second base film to obtain a water-repellent film, wherein the first base film or the second base film is a stretched film, And the manufacturing method of a water-repellent film whose tensile elasticity modulus is 1600 Mpa or more and 2600 Mpa or less. [Selection] Figure 2

Description

  The present invention relates to a method for producing a water-repellent film.

  An apparatus used outdoors or in a place where water scatters may require water repellency on the surface thereof. As a means for imparting water repellency to such a device, a water repellent film is applied to the device.

  As a method for producing a water-repellent film, a method for forming a water-repellent layer on the surface of the base film (for example, Patent Document 1), a method for providing a fine uneven structure on the surface of the base film (for example, Patent Document 2), etc. It has been known.

JP 2009-154480 A JP 2012-126073 A

However, the methods described in Patent Documents 1 and 2 require a material for forming a water-repellent layer and / or a special apparatus for forming a concavo-convex structure, and are therefore widely used in the film manufacturing process. Not easily implemented by equipment and materials.
Furthermore, the method described in Patent Document 1 has a problem that the durability of the water-repellent layer is insufficient, and the water-repellent layer is peeled off due to long-term use and the water repellency is lowered.

  Accordingly, an object of the present invention is to provide a method for producing a water-repellent film, which can be easily carried out and can produce a highly durable water-repellent film.

As a result of studying to solve the above-mentioned problems, the present inventor has shown that a water-repellent film can form a minute uneven structure on a peeled surface by bonding two substrate films and then peeling them. Inspired to be used in the manufacture of And it discovered that a water-repellent film could be easily manufactured with the equipment and material generally used in manufacture of a film by using a specific film as a film to bond. The present invention has been completed based on such findings.
That is, the present invention is as follows.

[1] A bonding step of bonding the first surface of the first base film and the first surface of the second base film via a bonding material to obtain a laminate, and the first A peeling step of peeling the base film and the second base film to obtain a water-repellent film,
The first base film or the second base film is
It is a stretched film and has a tensile elastic modulus of 1600 MPa to 2600 MPa,
A method for producing a water-repellent film.
[2] The method for producing a water-repellent film according to [1], wherein the first base film, the second base film, or both of them are films of an alicyclic structure-containing polymer resin. .
[3] The method for producing a water-repellent film according to [1] or [2], wherein the bonding material is an ultraviolet curable adhesive.

  The production method of the present invention can be easily carried out and can produce a highly durable water-repellent film.

FIG. 1 is a side view schematically showing a laminate obtained in the bonding step of the production method of the present invention. FIG. 2 is a side view schematically showing a pair of water-repellent films obtained by subjecting the laminate shown in FIG. 1 to a peeling step. FIG. 3 is an electron micrograph showing an example of the water-repellent surface of the water-repellent film obtained by the production method of the present invention.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and exemplifications, and may be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

  In the following description, “(meth) acryl” includes both acrylic and methacrylic. “(Meth) acrylate” includes both acrylate and methacrylate.

  In the following description, the direction of the element “parallel” may include an error within a range that does not impair the effect of the present invention, for example, within a range of ± 5 °, unless otherwise specified.

  Further, in the following description, a “long” film refers to a film having a length of at least 5 times the width, preferably having a length of 10 times or more, specifically Refers to a film having a length that can be wound or stored in a roll.

[1. Overview of manufacturing method)
The manufacturing method of the water-repellent film of the present invention includes a specific bonding step and a peeling step.

[2. (Bonding process)
In the bonding step, the first surface of the first base film and the first surface of the second base film are bonded through a bonding material to obtain a laminate.
FIG. 1 is a side view schematically showing a laminate obtained in the bonding step of the production method of the present invention. In FIG. 1, the laminated body 100 is provided with the 1st base film 111, the 2nd base film 112, and the bonding material layer 122 interposed between them.
In the laminate 100, the first base film 111 has a first surface 111U and a second surface 111D, and the second base film 112 has a first surface 112D and a second surface 112U. The first surface 111U of the first base film 111 and the first surface 112D of the second base film 112 are bonded via the bonding material 122, whereby the laminate 100 is configured.
In the example shown in FIG. 1, the entire surface of the first base film 111 and the second base film 112 is not pasted, but there is a part that is not pasted. That is, the 1st base film 111 has the non-bonding part 111G in the part, and the 2nd base film 112 has the non-bonding part 112G in the part.

  In the bonding step, a layer of a bonding material is provided on one or both of the first surface of the first base film and the first surface of the second base film, and then the first base film One surface and the first surface of the second base film can be brought into contact with each other in a state where they face each other. Simultaneously with the contact, or before or after the contact, operations such as heating and pressurization may be performed as necessary. The pressure when pressurizing is preferably 0.1 MPa or more, and preferably 1.3 MPa or less. By setting the pressure to be equal to or higher than the lower limit, the bonding can be sufficiently achieved. In particular, when an adhesive is used as the bonding material, it is possible to reduce the occurrence of uneven film thickness of the adhesive and achieve uniform peeling in the peeling step. On the other hand, the occurrence of problems such as wrinkles of the base film can be reduced by setting the pressure to the upper limit or less. The specific operation of the bonding step can be an operation suitable for the base film and the bonding material to be used.

[2.1. (Base film)
As a base film (a 1st base film and a 2nd base film) used for a pasting process, a resin film is usually used. As resin which comprises a base film, resin containing arbitrary polymers can be used. Especially, as resin which comprises a base film, a thermoplastic resin is preferable and it is especially preferable to use resin containing an alicyclic structure containing polymer. Hereinafter, the resin containing the alicyclic structure-containing polymer is appropriately referred to as “alicyclic structure-containing polymer resin”. The alicyclic structure-containing polymer resin is excellent in water repellency, transparency, low hygroscopicity, dimensional stability and light weight, and is suitable for an optical film.

  The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the structural unit of the polymer, a polymer having an alicyclic structure in the main chain, and an alicyclic structure in the side chain. Any of the polymers may be used. Moreover, an alicyclic structure containing polymer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Among these, a polymer containing an alicyclic structure in the main chain is preferable from the viewpoint of mechanical strength, heat resistance, and the like.

  Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Among these, from the viewpoints of mechanical strength, heat resistance and the like, a cycloalkane structure and a cycloalkene structure are preferable, and a cycloalkane structure is particularly preferable.

  The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, particularly preferably per alicyclic structure. Is a range of 15 or less. Thereby, the mechanical strength, heat resistance, and moldability of the base film are highly balanced and suitable.

  The proportion of the structural unit having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected depending on the purpose of use, preferably 55% by weight or more, more preferably 70% by weight or more, particularly preferably. Is 90% by weight or more. When the ratio of the structural unit having an alicyclic structure in the alicyclic structure-containing polymer is in this range, it is preferable from the viewpoint of the transparency and heat resistance of the base film.

  Examples of alicyclic structure-containing polymers include norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrides thereof. Can be mentioned. Among these, norbornene-based polymers are preferable because of their good transparency and moldability.

  Examples of the norbornene-based polymer include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and an arbitrary monomer, or a hydride thereof; An addition polymer of a monomer having a norbornene structure, an addition copolymer of a monomer having a norbornene structure and an arbitrary monomer, or a hydride thereof. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, and the like. It is. Here, the “(co) polymer” includes both a polymer and a copolymer.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene), tricyclo [4.3.0.1 ^2,5 ] deca-3,7. -Diene (common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4. 0.1 ^2,5 . ^{17, 10} ] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. Moreover, these substituents may be the same or different, and a plurality thereof may be bonded to the ring. Moreover, the monomer which has a norbornene structure may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  Examples of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfonic acid group.

  Examples of an optional monomer capable of ring-opening copolymerization with a monomer having a norbornene structure include, for example, monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof; and cyclic conjugates such as cyclohexadiene and cycloheptadiene. Dienes and derivatives thereof; and the like. As the optional monomer capable of ring-opening copolymerization with a monomer having a norbornene structure, one kind may be used alone, or two or more kinds may be used in combination at any ratio.

  A ring-opening polymer of a monomer having a norbornene structure, and a ring-opening copolymer of any monomer copolymerizable with a monomer having a norbornene structure are, for example, a known ring-opening monomer. It can be produced by polymerization or copolymerization in the presence of a polymerization catalyst.

  Examples of any monomer that can be addition copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and derivatives thereof; cyclobutene, cyclopentene, And cycloolefins such as cyclohexene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene; and the like. Among these, α-olefin is preferable and ethylene is more preferable. Moreover, the arbitrary monomer which can carry out addition copolymerization with the monomer which has a norbornene structure may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  An addition copolymer of a monomer having a norbornene structure and an addition copolymer of any monomer that can be copolymerized with a monomer having a norbornene structure include, for example, a monomer of a known addition polymerization catalyst. It can be produced by polymerization or copolymerization in the presence.

  Examples of the monocyclic olefin polymer include addition polymers of a cyclic olefin monomer having a single ring such as cyclohexene, cycloheptene, and cyclooctene.

  Examples of the cyclic conjugated diene polymer include polymers obtained by cyclization reaction of addition polymers of conjugated diene monomers such as 1,3-butadiene, isoprene and chloroprene; cyclic conjugates such as cyclopentadiene and cyclohexadiene. And 1,2- or 1,4-addition polymers of diene monomers; and their hydrides.

  Examples of vinyl alicyclic hydrocarbon polymers include polymers of vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane and their hydrides; vinyl aromatic hydrocarbons such as styrene and α-methylstyrene. Hydrogenated product obtained by hydrogenating an aromatic ring part contained in a polymer obtained by polymerizing monomers; vinyl alicyclic hydrocarbon monomer, or vinyl aromatic hydrocarbon monomer and vinyl aromatic hydrocarbon monomer And an aromatic ring hydride of a copolymer such as a random copolymer or a block copolymer with an arbitrary copolymerizable monomer. Examples of the block copolymer include a diblock copolymer, a triblock copolymer or a multi-block copolymer having more than that, a gradient block copolymer, and the like.

  The weight average molecular weight (Mw) of the polymer contained in the resin constituting the base film is usually 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and usually 100,000 or less. Preferably it is 80,000 or less, More preferably, it is 50,000 or less. Here, the weight average molecular weight is calculated by polyisoprene or polystyrene measured by gel permeation chromatography using cyclohexane as a solvent (however, toluene may be used when the sample does not dissolve in cyclohexane). The weight average molecular weight. When the weight average molecular weight is in such a range, the mechanical strength and molding processability of the base film are highly balanced and suitable.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the polymer contained in the resin constituting the base film is usually 1.2 or more, preferably 1.5 or more, more preferably 1. It is 8 or more, usually 3.5 or less, preferably 3.0 or less, more preferably 2.7 or less. By making molecular weight distribution more than the lower limit of the said range, productivity of a polymer can be improved and cost can be suppressed. Moreover, since a low molecular weight component can be reduced by making it below an upper limit, relaxation time can be lengthened. Therefore, relaxation at high temperature exposure can be suppressed, and the stability of the base film can be enhanced.

The object to which the water-repellent film obtained by the production method of the present invention is attached may be required to have optical transparency and a predetermined optical property such as a display surface of a liquid crystal display device. When producing a water-repellent film used for such applications, the polymer contained in the resin constituting the base film preferably has an absolute value of the photoelastic coefficient C of 10 × 10 ⁻¹² Pa ⁻¹ or less. 7 × 10 ⁻¹² Pa ⁻¹ or less is more preferable, and 4 × 10 ⁻¹² Pa ⁻¹ or less is particularly preferable. The photoelastic coefficient C is a value represented by “C = Δn / σ” where birefringence is Δn and stress is σ. By keeping the photoelastic coefficient of the polymer within the above range, the variation in the in-plane retardation Re of the base film can be reduced.

  The saturated water absorption rate of the polymer contained in the resin constituting the base film is preferably 0.03% by weight or less, more preferably 0.02% by weight or less, and particularly preferably 0.01% by weight or less. When the saturated water absorption is in the above range, the change over time of the mechanical properties and optical properties of the resulting water-repellent film can be reduced.

  The saturated water absorption is a value expressed as a percentage with respect to the mass of the test piece before immersion, which is obtained by immersing the test piece in water at a constant temperature for a certain period of time. Usually, it is measured by immersing in 23 ° C. water for 24 hours. The saturated water absorption in the polymer can be adjusted to the above range, for example, by reducing the amount of polar groups in the polymer. From the viewpoint of lowering the saturated water absorption rate, the polymer preferably does not have a polar group.

  The resin constituting the base film may contain any component other than the polymer as long as the effects of the present invention are not significantly impaired. Examples of the optional components include colorants such as pigments and dyes; plasticizers; fluorescent brighteners; dispersants; thermal stabilizers; light stabilizers; ultraviolet absorbers; antistatic agents; An additive such as a surfactant. These components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  However, the amount of the polymer contained in the resin constituting the base film is generally 50% to 100%, or 70% to 100%. By setting the ratio of the amount of the polymer to a high value above a certain value, the preferable properties of the polymer can be expressed well. For example, when the polymer is an alicyclic structure-containing polymer, advantages such as transparency, low hygroscopicity, dimensional stability and light weight can be enjoyed at a high level.

The base film may be a single-layer film including only one layer, or may be a multilayer film having two or more layers.
When a base film is provided with two or more layers, two or more types of one type of film layer may be provided, or two or more types of different film layers may be provided. When the base film has a multilayer structure, from the viewpoint of obtaining a water-repellent film having good physical properties, it is preferable that one or more layers included in the base film are made of an alicyclic structure-containing polymer resin. It is particularly preferable that the first surface of the base film is made of an alicyclic structure-containing polymer resin. Moreover, you may provide the layer which consists of resin other than the alicyclic structure containing polymer resin mentioned above in a base film. Examples of the layer made of other than the alicyclic structure-containing polymer resin include a film layer having functions such as antireflection, antistatic, and antiglare.

  When manufacturing the water-repellent film which has a light transmittance with the manufacturing method of this invention, the base film used for manufacture shall have a light transmittance. In this case, the base film preferably has a total light transmittance in terms of 1 mm thickness of 70% or more, more preferably 80% or more. The total light transmittance can be measured using a spectrophotometer (manufactured by JASCO Corporation, ultraviolet-visible near-infrared spectrophotometer “V-570”) in accordance with JIS K0115. The base film preferably has a haze at a thickness of 1 mm of 5% or less, and more preferably 3% or less. Here, the haze is an average value obtained by measuring five points using a “turbidimeter NDH-300A” manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS K7361-1997.

  The base film may have a width direction dimension of, for example, 1000 mm to 3000 mm. Although there is no restriction | limiting in the dimension of the longitudinal direction of a base film, It is preferable that it is a long film. By using a long film, efficient production becomes possible.

  The average thickness of the base film is preferably 5 μm or more, more preferably 20 μm or more, preferably 500 μm or less, more preferably 300 μm or less. The thickness variation width of the base film is preferably within ± 3% of the average thickness over the longitudinal direction and the width direction. By setting the thickness variation within the above range, variations in mechanical properties and optical properties of the obtained water-repellent film can be reduced.

  The amount of the volatile component contained in the base film is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and further preferably 0.02% by weight or less. By setting the amount of the volatile component within the above range, the dimensional stability can be improved, and the change over time in the mechanical properties and optical properties of the resulting water-repellent film can be reduced. Here, the volatile component is a substance having a molecular weight of 200 or less. Examples of volatile components include residual monomers and solvents. The amount of volatile components can be quantified by analyzing by gas chromatography as the sum of substances having a molecular weight of 200 or less.

  There is no restriction | limiting in the manufacturing method of a base film. The base film is obtained by molding a resin for forming the base film by a known film forming method. Examples of the film forming method include a cast forming method, an extrusion forming method, and an inflation forming method. Among these, a melt extrusion method that does not use a solvent can reduce the amount of residual volatile components efficiently, and is preferable from the viewpoints of the global environment and work environment, and excellent manufacturing efficiency. Examples of the melt extrusion method include an inflation method using a die, and among them, a method using a T die is preferable in terms of excellent productivity and thickness accuracy.

  Each of the base films may be a multilayer film having two or more layers, but is preferably a single-layer film from the viewpoint of generating well-controlled cohesive failure.

[2.2. Stretching process and relationship between first substrate film and second substrate film]
The base film may be an unstretched film that has not been stretched, or a stretched film that has been stretched. However, in the production method of the present invention, the first base film or the second base film is a stretched film, and the tensile elastic modulus is 1600 MPa or more and 2600 MPa or less. In the following description, the case where the first base film is a stretched film and the tensile elastic modulus is 1600 MPa or more and 2600 MPa or less will be described unless otherwise specified.

  The stretched film is obtained by stretching the unstretched base film obtained by the above method. The stretching method is not particularly limited, and for example, either a uniaxial stretching method or a biaxial stretching method may be adopted. As an example of the stretching method, as an example of the uniaxial stretching method, a method of uniaxial stretching in the longitudinal direction using a difference in peripheral speed of a roll for film conveyance; uniaxial stretching in the width direction using a tenter stretching machine And the like. In addition, as an example of the biaxial stretching method, simultaneous biaxial stretching method that stretches in the width direction according to the spread angle of the guide rail at the same time as stretching in the longitudinal direction with an interval between the clips to be fixed; roll for film conveyance The biaxial stretching method such as the sequential biaxial stretching method is used in which the two ends are clipped and stretched in the width direction using a tenter stretching machine. Can be mentioned. Furthermore, it is neither parallel nor perpendicular to the width direction of the film using, for example, a tenter stretching machine that can apply a feeding force, a pulling force, or a pulling force at different speeds in the width direction or the longitudinal direction. An oblique stretching method in which oblique stretching is continuously performed in the direction may be used.

  Examples of the apparatus used for stretching include a longitudinal uniaxial stretching machine, a tenter stretching machine, a bubble stretching machine, and a roller stretching machine. The stretching temperature is preferably (Tg-30 ° C) or higher, more preferably (Tg-10 ° C) or higher, preferably (Tg + 60 ° C) or lower, where Tg is the glass transition temperature of the resin constituting the stretched film. More preferably, it is (Tg + 50 ° C.) or less.

  The draw ratio is usually 1.05 times or more, preferably 1.1 times or more, and usually 10.0 times or less, preferably 2.0 times or less. By making a draw ratio below the said upper limit, the intensity | strength of the water-repellent film obtained can be kept at a desired high value. By setting the draw ratio to the above lower limit or more, cohesive failure in the layer of the first base film can be generated in a good mode, and as a result, a water-repellent film of good quality can be easily produced. Can do.

The tensile modulus of the first base film is 1600 MPa or more, preferably 1800 MPa or more. On the other hand, the upper limit of the tensile elastic modulus of the first base film is 2600 MPa or less, preferably 2400 MPa or less, more preferably 2200 MPa or less.
When the tensile elastic modulus is equal to or higher than the lower limit, in the peeling step, the cohesive failure in the layer of the first base film can be generated in a good mode. It can be manufactured easily. On the other hand, when the tensile elastic modulus is not more than the above upper limit, the strength of the obtained water-repellent film can be maintained at a desired high value.

  The second base film may be a stretched film or an unstretched film. When the stretched film is compared with the unstretched film, the stretched film is more likely to cause cohesive failure because the molecular entanglement is relatively small. Therefore, when the unstretched film is used as the second base film, the first base Better controlled cohesive failure can occur in the layers of the material film. However, even if the second base film is a stretched film, controlled cohesive failure can be generated in the layer of the first base film depending on the peeling mode. The tensile elastic modulus of the second base film can be preferably 1000 MPa or more from the viewpoint of easily causing cohesive failure. The upper limit is not particularly limited, but is 5000 MPa or less.

When the base film has two or more layers, a stretched film may be obtained by laminating a stretched film layer in advance, and stretched to a pre-stretch film having a multilayer structure obtained by coextrusion or the like. You may process and obtain a stretched film.
When each of the base films includes two or more layers, when at least the layer constituting the first surface of the base film satisfies the above requirements, the base film satisfying the above requirements is used in the production method of the present invention. sell. For example, when the first base film includes two or more layers, when the layer constituting the first surface is a stretched film having a tensile elastic modulus of 1600 MPa or more, the film is the first base film. Can be used as

[2.3. (Bonding material)
As an example of the bonding material interposed between the first base film and the second base film during the bonding step,
An adhesive capable of forming an adhesive layer that bonds the first base film and the second base film. A chemical bond is formed between the first base film and the second base film. Materials such as coupling agents that can be used.

[2.4. adhesive〕
Examples of adhesives include water-based adhesives, solvent-based adhesives, two-component curable adhesives, photo-curable adhesives, and pressure-sensitive adhesives. Among these, a photocurable adhesive is preferable. Moreover, an adhesive agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  As the photocurable adhesive, for example, an acrylate adhesive containing urethane (meth) acrylate, hydroxyalkyl (meth) acrylate, and acrylamide derivative can be used. These adhesives may be UV curable adhesives. By using an ultraviolet curable adhesive as the bonding material, it can be applied and cured more quickly than other types of adhesives and silane coupling agents. Sex can be obtained.

Urethane (meth) acrylate, for example, after reacting a polyisocyanate and a polyol, further reacting a hydroxyl group-containing (meth) acryl compound and, if necessary, a hydroxyl group-containing allyl ether compound, thereby producing a radically polymerizable unsaturated group. It can be obtained as a containing oligomer. In addition, urethane (meth) acrylate can be obtained, for example, by reacting a hydroxyl group-containing (meth) acrylic compound with a polyol and further reacting with polyisocyanate.
As urethane (meth) acrylate, use urethane (meth) acrylate having 2 to 3 double bonds per molecule and having a number average molecular weight of 500 to 3000 per double bond. However, it is preferable because it is easy to balance adhesive strength, flexibility, photocurability, viscosity, and the like.
The amount of urethane (meth) acrylate in the photocurable adhesive is usually 30% by weight to 50% by weight. By making the amount of urethane (meth) acrylate not less than the lower limit of the above range, the adhesive layer can be prevented from becoming brittle. Moreover, by making it into below an upper limit, the viscosity of an adhesive agent can be made low and adhesive strength can be made high.

Examples of the hydroxyalkyl (meth) acrylate include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate. Among these, hydroxyethyl methacrylate is particularly preferable.
The amount of hydroxyalkyl (meth) acrylate in the photocurable adhesive is usually 13 wt% to 40 wt%. By setting the amount of hydroxyalkyl (meth) acrylate to be equal to or higher than the lower limit of the above range, the hydrophilicity of the entire adhesive can be set to an appropriate range. Moreover, by making it into an upper limit or less, it can prevent that an adhesive bond layer becomes weak, and can make photocurability of an adhesive agent high.

Examples of acrylamide derivatives include N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-dimethylaminoethylacrylamide, N, N-dimethylaminopropylacrylamide, N-isopropylacrylamide, and N, N-dimethylamino. Examples thereof include propylacrylamide and N-hydroxyethylacrylamide. Of these, N, N-diethylacrylamide, N-isopropylacrylamide, N, N-dimethylaminopropylacrylamide, and N-hydroxyethylacrylamide are particularly preferable.
The amount of acrylamide in the photocurable adhesive is usually in the range of 0 to 30% by weight, preferably 1 to 30% by weight.

  The photocurable adhesive preferably contains 30% to 40% by weight of isobornyl (meth) acrylate in addition to the components described above. By including isobornyl (meth) acrylate, heat resistance is imparted to the adhesive layer. Furthermore, it is possible to easily adjust the viscosity for improving the coating performance without deteriorating the adhesive performance.

  The photocurable adhesive preferably contains a photopolymerization initiator. Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4- Chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane -1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chloro Thioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino - propan-1-one, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, and the like. Moreover, the quantity of the photoinitiator in a photocurable adhesive agent is 2 to 10 weight% normally.

  The viscosity of the adhesive at 23 ° C. is usually 20 mPa · s or more, preferably 30 mPa · s or more, more preferably 50 mPa · s or more, usually 5000 mPa · s or less, preferably 3000 mPa · s or less, more preferably 1500 mPa. -S or less.

  The adhesive is used as a bonding material by interposing the adhesive between the first surface of the first base film and the first surface of the second base film, and further curing as necessary. A laminated body can be obtained. More specifically, for example, after applying an adhesive to the first surface of the first base film and / or the first surface of the second base film, the first using a laminating device such as a roll laminator. The base film and the second base film can be bonded together and dried or irradiated with light such as ultraviolet rays as necessary to form an adhesive layer.

  The average thickness of the adhesive layer is preferably 0.1 μm or more, more preferably 0.3 μm or more, preferably 50 μm or less, more preferably 30 μm or less. When the thickness of the adhesive layer is equal to or less than the above upper limit, a force at the time of peeling can be applied to the base film, and desired cohesive failure in the base film layer can be easily caused. Moreover, when the thickness of the adhesive layer is equal to or more than the lower limit, the strength of the adhesive layer can be ensured and desired cohesive failure in the base film layer can be easily caused.

  The storage modulus of the adhesive layer is preferably 3.00 GPa or more, more preferably 3.50 GPa or more. The upper limit is not particularly limited, but is 10.0 GPa or less. When the storage elastic modulus is within the above range, desired cohesive failure in the base film layer can be easily caused. The storage elastic modulus can be measured using a TI-950 TriboIndenter manufactured by HYSITRON under conditions of normal temperature, 300 Hz, and an indentation depth of 50 nm.

[2.5. Modification process)
Prior to the formation of the adhesive layer, it is preferable to improve the adhesion between the base film and the adhesive layer by subjecting the surface of the base film to a modification treatment. Examples of the surface modification treatment for the base film include energy ray irradiation treatment, primer treatment, and chemical treatment. Examples of the energy ray irradiation treatment include corona discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet ray irradiation treatment, etc., and from the viewpoint of treatment efficiency, corona discharge treatment and plasma treatment are preferred, and corona discharge treatment is particularly preferred. preferable. Examples of the primer treatment include a treatment for forming a polyurethane layer on the surface of the base film. Examples of the chemical treatment include a saponification treatment, a method of immersing in an aqueous oxidizing agent solution such as potassium dichromate solution and concentrated sulfuric acid, and then washing with water.

  For the corona discharge treatment, the electrode structure is preferably a wire electrode, a planar electrode, or a roll electrode. Examples of the material of the electrode include metals such as iron, copper, aluminum, and stainless steel. Examples of the electrode shape include a thin plate shape, a knife edge shape, and a brush shape.

  Further, in the corona discharge treatment, it is preferable to carry out the treatment by sandwiching a dielectric between the film to be treated and the electrode in order to make the discharge uniform. It is preferable to use a dielectric having a relative dielectric constant of 10 or more. The dielectric structure is preferably a structure in which electrodes of both electrodes are sandwiched between dielectrics. Examples of the dielectric material include ceramics; plastics such as silicon rubber, polytetrafluoroethylene, and polyethylene terephthalate; glass; quartz; silicon dioxide; metal oxides such as aluminum oxide, zirconium dioxide, and titanium dioxide; barium titanate and the like. And the like. In particular, it is advantageous to interpose a solid dielectric having a relative dielectric constant of 10 or more (under an environment of 25 ° C.) in that corona discharge treatment can be performed at a low voltage and at a high speed. Examples of the solid dielectric having a relative dielectric constant of 10 or more include metal oxides such as zirconium dioxide and titanium dioxide; oxides such as barium titanate; and silicon rubber. The thickness of the dielectric is preferably in the range of 0.3 mm to 1.5 mm. Dielectric breakdown can be prevented by setting the thickness of the dielectric to be equal to or greater than the lower limit of the above range. Moreover, since it is not necessary to raise an applied voltage by making it below an upper limit, processing efficiency can be improved.

  In the corona discharge treatment, the distance between the film to be treated and the electrode is preferably 0.5 mm to 10 mm. By setting the interval to be equal to or greater than the lower limit of the above range, even a thick film can be passed between the electrodes. For this reason, even if it is a film which has thick parts, such as a seam, for example, since it can pass between electrodes stably, the damage of a film can be prevented. Further, by making the voltage lower than the upper limit value, the applied voltage can be lowered, so that the power source can be miniaturized and the discharge can be prevented from becoming a streamer shape.

  The output of the corona discharge treatment is preferably performed under the condition that the damage to the surface to be treated is as small as possible. Specifically, it is preferably 0.02 kW or more, more preferably 0.04 kW or more, preferably 5 kW or less, more preferably Is 2 kW or less. Further, within this range, it is a preferable corona discharge treatment method to perform the corona discharge treatment several times at the lowest possible output.

The density of the corona discharge treatment is preferably 1 W · min / m ² or more, more preferably 5 W · min / m ² or more, particularly preferably 10 W · min / m ² or more, preferably 1000 W · min / m ² or less. More preferably, it is 500 W · min / m ² or less, and particularly preferably 300 W · min / m ² or less. By setting the treatment density to be equal to or higher than the lower limit of the above range, the applicability of the urethane composition can be improved. Moreover, the fall of the adhesiveness by prevention by destruction of a process surface can be prevented by making it into an upper limit or less.

  The frequency of the corona discharge treatment is preferably 5 kHz or more, more preferably 10 kHz or more, preferably 100 kHz or less, more preferably 50 kHz or less. By setting the frequency to be equal to or higher than the lower limit value of the above range, the uniformity of the corona discharge treatment can be improved, so that unevenness of the corona discharge treatment can be prevented. Moreover, the stable corona discharge process can be performed by making it below an upper limit.

  When corona discharge treatment is performed by surrounding the electrode with a casing, putting an inert gas inside the casing, and applying gas to the electrode portion, the discharge can be generated in a finer state. As an inert gas, helium, argon, nitrogen etc. are mentioned, for example. An inert gas may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  When performing plasma treatment as the modification treatment, examples of the plasma discharge treatment include glow discharge treatment and flame plasma treatment. As the glow discharge treatment, either a vacuum glow discharge treatment performed under vacuum or an atmospheric pressure glow discharge treatment performed under atmospheric pressure can be used. Among these, from the viewpoint of productivity, atmospheric pressure glow discharge treatment performed under atmospheric pressure is preferable. Here, the atmospheric pressure is in the range of 700 Torr to 780 Torr.

  In the glow discharge treatment, a film to be treated is placed between opposing electrodes, a plasma-exciting gas is introduced into the apparatus, and a high-frequency voltage is applied between the electrodes to excite the gas between the electrodes. Glow discharge is performed. This further increases the hydrophilicity of the treated surface.

  A plasma-excitable gas refers to a gas that can be plasma-excited under the above conditions. Examples of the plasma-exciting gas include rare gases such as argon, helium, neon, krypton, and xenon; nitrogen; carbon dioxide; chlorofluorocarbons such as tetrafluoromethane and mixtures thereof; and inert gases such as argon and neon. , A reactive gas capable of imparting a polar functional group such as a carboxyl group, a hydroxyl group or a carbonyl group; Moreover, plasma excitation gas may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The frequency of the high frequency voltage in the plasma treatment is preferably in the range of 1 kHz to 100 kHz. The magnitude of the voltage is preferably in a range in which the electric field strength when applied to the electrode is 1 kV / cm to 100 kV / cm.

  When performing a saponification process as a modification process, an alkali saponification process is suitable as the saponification process. Examples of the treatment method include an immersion method and an alkaline solution coating method, and the immersion method is preferable from the viewpoint of productivity.

  The dipping method in the saponification treatment is a technique in which a film to be treated is dipped in an alkaline solution under appropriate conditions, and all surfaces having reactivity with alkali on the entire surface of the film are saponified. The immersion method is preferable from the viewpoint of cost because it does not require special equipment. The alkaline liquid is preferably a sodium hydroxide aqueous solution. The concentration of the alkaline solution is preferably 0.5 mol / liter or more, more preferably 1 mol / liter or more, preferably 3 mol / liter or less, more preferably 2 mol / liter or less. The liquid temperature of the alkaline solution is preferably 25 ° C. or higher, more preferably 30 ° C. or higher, preferably 70 ° C. or lower, more preferably 60 ° C. or lower. In order to set the average water contact angle of the treated surface and the standard deviation of the water contact angle within a desired range, for example, the dipping time is appropriately adjusted.

  After immersing the film in the alkaline solution, the film is thoroughly washed with water so that the alkali component does not remain in the treated film, or the alkali component is neutralized by immersing the film in dilute acid. It is preferable.

When performing ultraviolet irradiation treatment as the modification treatment, the wavelength of ultraviolet rays to be irradiated is usually 100 nm to 400 nm. The output value of the lamp, which is an ultraviolet light source, is usually 120 W or more, preferably 160 W or more, and is usually 240 W or less, preferably 200 W or less. The irradiation amount of ultraviolet rays is preferably 100 mJ / cm ² or more, more preferably 200 mJ / cm ² or more, and particularly preferably 300 mJ / cm, when expressed as the total amount of accumulated ultraviolet light with respect to the object irradiated with ultraviolet rays. cm ^{2 or} more, preferably 2,000 mJ / cm ² or less, more preferably 1,500 mJ / cm ² or less, particularly preferably 1,000 mJ / cm ² or less. The total amount of integrated light is a value determined by the illuminance of the ultraviolet irradiation lamp and the line speed (film moving speed), and can be measured by, for example, an ultraviolet integrated illuminometer (EYEUV METER UVPF-A1 manufactured by Eye Graphic).

[2.6. (Coupling agent)
As an example of the coupling agent as the bonding material, a silane coupling agent used for surface treatment of the material may be mentioned.
As specific examples of the silane coupling agent,
Having vinyl groups such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane;
Having an epoxy group such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane;
having a styryl group such as p-styryltrimethoxysilane;
Those having a methacryloxy group such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxymethyldiethoxysilane, 3-methacryloxytriethoxysilane;
Having an acryloxy group such as 3-acryloxypropyltrimethoxysilane;
N-2-aminoethyl-3-aminopropylmethyldimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane Methoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidenepropylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2 -Those having an amino group such as aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, special aminosilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-6135, etc.);
Having a ureido bond such as 3-ureidopropyltriethoxysilane;
Containing halogen atoms such as 3-chloropropyltrimethoxysilane;
Those having a mercapto group such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane;
Having a sulfide bond such as bis (triethoxysilylpropyl) tetrasulfide;
Having an isocyanate group such as 3-isocyanatopropyltriethoxysilane;
Etc. One of these can be used alone, or two or more can be used in combination.

  Gas containing the vaporized silane coupling agent (hereinafter sometimes referred to as “treatment gas”) is applied to the first surface of the first base film and / or the first surface of the second base film. By treating these surfaces by contact, and then crimping the first substrate film and the second substrate film under appropriate conditions, a laminate using a silane coupling agent as a bonding material can be obtained. . The treatment with the treatment gas may be performed on only one of the first surface of the first base film and the first surface of the second base film, but is usually performed on both of them.

The processing gas can contain a carrier gas in addition to the silane coupling agent. As such a carrier gas, an inert gas such as nitrogen, helium, or argon can be used.
The concentration of the silane coupling agent in the processing gas (ratio where the saturation concentration is 100%) is preferably 20% or more, more preferably 40% or more, still more preferably 60% or more, and It is 100% or less, preferably 95% or less, and more preferably 90% or less. By setting the silane coupling agent concentration to 20% or more of the saturation concentration, cohesive failure in the layer of the first base film can be generated in a good manner in the peeling step, and as a result, good quality The water-repellent film can be easily produced.

  The processing gas can further contain water vapor as required. By containing water vapor, a silane coupling treatment that provides high peel strength can be achieved more efficiently. The content ratio of water vapor in the processing gas can be 5% to 100% of the saturation concentration.

  The processing gas can further contain an optional gas component as required. Examples of such optional gas components include methanol and ethanol. The content ratio of an arbitrary gas component in the processing gas can be 0.1% to 10% of the saturation concentration.

  When a silane coupling agent is used as the bonding material, the thickness of the layer of the bonding material is usually in the range of 5 nm or less.

  Prior to the treatment with the coupling agent, it is preferable to modify the surface of the base film to improve the effect of the coupling agent. An example of such a modification process is the same process as the modification process prior to the formation of the adhesive layer described above.

[3. (Peeling process)
In the peeling step, the first base film and the second base film are peeled to obtain a water repellent film.
As an example of a more specific operation of peeling, one end of the first base film or the second base film in the laminate is gripped, and from the end, the other end Peeling can be achieved by pulling the gripped film so that the peel position moves.
When the base film is a long film, it is preferable that the longitudinal direction is the peeling direction in order to increase the production efficiency.
There is no particular limitation on the peeling speed, but if the peeling speed is too low, the productivity is poor. Conversely, if the peeling speed is too high, the stress at the time of peeling may increase and the substrate may break. Therefore, it is preferable to increase the peeling speed to such an extent that the substrate does not break, because stable production can be performed with high productivity.

  When the first base film is a stretched film and the tensile modulus is 1600 MPa or more, a cohesive failure is generated in the layer of the first base film by performing a peeling step, and the first base film A part of the material film can be peeled off from the remaining part of the laminate. Such cohesive failure can be achieved by using the above-mentioned predetermined one as the first base film and appropriately adjusting the material for the bonding material and the second base film and the formation conditions of the laminate. . By this peeling step, a fine uneven structure due to cohesive failure can be formed on a part of the separated first base film and the peeled surface of the remaining part of the laminate. Any of these can be a water-repellent film as a product. The cohesive failure caused by the peeling step is preferably expressed only in the layer of the first base film or only in the layer of the second base film, and particularly only in the layer of the first base film. It is particularly preferable to stably produce a large-area, homogeneous water-repellent film in which the cohesive failure of the embodiment produced and thereby produced has occurred.

  FIG. 2 is a side view schematically showing a pair of water-repellent films obtained by subjecting the laminate shown in FIG. 1 to a peeling step. A part of the first base film 111 in FIG. 1 becomes a first water-repellent film 211 by cohesive failure. The remaining 212 of the first base film 111, the bonding material layer 122, and the second base film 112 constitute a second water-repellent film 202. Both the peeling surface 211U of the first water-repellent film 211 and the peeling surface 202D of the second water-repellent film 202 have a fine concavo-convex structure generated by cohesive failure of the first base film 111. Since the release surface has a higher water repellent effect than a case where there is no fine uneven structure, it can be used as a water repellent surface.

  FIG. 3 is an electron micrograph showing an example of the water-repellent surface of the water-repellent film obtained by the production method of the present invention. Thus, a fine concavo-convex structure is formed on the surface of the water-repellent surface due to cohesive failure, whereby a high water-repellent effect can be obtained.

[4. (Water-repellent film)
By the production method of the present invention, the above-described first water-repellent film and second water-repellent film can be obtained as the water-repellent film. Unlike the concavo-convex structure constituted by particles or the like, the interface of the water-repellent film is a concavo-convex structure constituted by a base film, and therefore has high durability during use. In particular, the first water-repellent film can be a film that is particularly excellent in durability during use because the concavo-convex structure and the substrate are integrated.

  The water-repellent film obtained by the production method of the present invention can be applied to a surface where it is preferable to reduce undesired phenomena such as adhesion of dirt due to adhesion of water droplets, deterioration of aesthetics, and deterioration of visibility. For example, the present invention can be applied to the surface of an apparatus or member used in a place where water droplets are easily attached due to a phenomenon such as rainfall, condensation, or water splash. Specifically, it can be applied to surfaces such as windows, display devices used outdoors or in bathrooms, and lighting.

  The water-repellent film can be used by sticking to the surface to be applied through a layer such as an adhesive layer as necessary. Specifically, an adhesive layer is formed on the surface opposite to the water repellent surface (the surface 211D for the first water repellent film 211 shown in FIG. 2 and the surface 202U for the second water repellent film 202). And a water-repellent film can be used by sticking on the surface of an application object through the said adhesive bond layer.

  The water repellency obtained when a material having optical transparency is used as the base film (or a base film and a bonding material in the case where the second water repellent film 202 shown in FIG. 2 has a layer structure). The film may also be light transmissive. For example, the water repellent film can have a total light transmittance in terms of 1 mm thickness of preferably 70% or more, more preferably 80% or more. Further, the haze in terms of 1 mm thickness of the water repellent film can be preferably 5% or less, more preferably 3% or less. By having such characteristics, the water-repellent film can be favorably applied to members or devices that require light transmission, such as windows and display devices.

  The water repellent surface of the water repellent film can have an average water contact angle of preferably 115 ° or more, more preferably 120 ° or more. By appropriately selecting the material of the base film, it is possible to obtain an average water contact angle of about 110 ° even if the surface of the base film is smooth, but the water repellent film obtained by the production method of the present invention Can obtain an even higher average water contact angle due to the fine uneven structure on the water repellent surface.

The average water contact angle can be determined by the θ / 2 method using a contact angle meter.
The average water contact angle is calculated, for example, by measuring 20 water contact angles randomly selected within a range of 100 cm ^{2 on} the surface of the measurement target and adding the measured values.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples shown below, and the scope of the claims of the present invention and the equivalents thereof are not deviated from. Any change can be made.
Further, in the following description, “parts” and “%” indicating amounts are based on weight unless otherwise specified. In addition, the operations described below were performed under normal temperature and normal pressure conditions unless otherwise specified.

[Explanation of evaluation method]
(Tensile modulus)
The tensile modulus of the film is in accordance with JIS K7113, and the tensile elasticity of the film in the longitudinal direction (MD direction) and in the width direction (TD direction) with a tensile tester (Instron, 5564 type digital material tester). The rate was measured. The measurement conditions were a tensile speed of 5 m / min, a test count of 5 times, a room temperature of 23 ° C., and a humidity of 50% RH. In the measurement of the tensile modulus, the strain was measured by placing a point at a distance of 50 mm in the center of the test piece and measuring the distance between the two points with a video extensometer (manufactured by Instron).

(Contact angle)
The contact angle of the water repellent surface of the water repellent film was measured according to JIS R3257: 1999.
Using an automatic contact angle meter (model name: DropMaster500) manufactured by Kyowa Interface Science Co., Ltd., the contact angle was determined using distilled water as droplets.

(Storage modulus)
The storage elastic modulus of the adhesive layer was obtained by peeling the adhesive layer from a part of the obtained laminate and using it as a sample, using TI-950 TriboIndenter manufactured by HYSITRON at room temperature, 300 Hz, and an indentation depth of 50 nm. Measured at

[Example 1]
(1-1. Second base film: Production of unstretched film)
A pellet of a norbornene polymer (trade name “ZEONOR 1420”, manufactured by Nippon Zeon Co., Ltd .; glass transition temperature Tg 136 ° C.) was dried at 100 ° C. for 4 hours using a hot air dryer in which air was circulated. The pellets were then used with a 50 mm single-screw extruder provided with a leaf disk-shaped polymer filter (filtration accuracy 30 μm) and a 650 mm wide T-die with a surface roughness Ra = 0.15 μm chrome plated. And extruded at 260 ° C. The extruded sheet-shaped norbornene polymer was brought into close contact with the first cooling drum (diameter 250 mm, temperature: 135 ° C., peripheral speed R1: 25.7 m / min), and then the second cooling drum (diameter 250 mm, temperature 125 ° C.). , Peripheral speed R2: 25.7 m / min), and then transferred in close contact with the third cooling drum (diameter 250 mm, temperature 100 ° C., peripheral speed R3: 25.5 m / min), with a width of 600 mm and a length of 300 m. An unstretched film 1 was obtained. Of these transfer paths, the sheet-shaped norbornene-based polymer extruded from the opening of the T-shaped die is covered with an aluminum enclosure member to the first contact with the first cooling drum, and the enclosure member forms a sheet form. The distance to the cooling drum to which the molten resin first adhered was 80 mm. It was 1650 MPa when the tensile elasticity modulus of the obtained unstretched film 1 was measured.

(1-2. First base film: production of stretched film)
The unstretched film 1 produced in (1-1) is continuously supplied to a floating-type longitudinal stretching apparatus as it is, and after longitudinal stretching is performed at 140 ° C. and 1.3 times, further continuously into a tenter. Supplied. In the tenter, the film was stretched in a direction perpendicular to the traveling direction at 145 ° C. and 1.5 times. Thereby, the stretched film 1 was obtained. It was 1630 MPa when the tensile elasticity modulus of the obtained stretched film 1 was measured.

(1-3. Bonding step: production of laminate)
A laminate having the structure schematically shown in FIG. 1 was produced by the following operation.
One surface of the stretched film 1 obtained in (1-2) (corresponding to the first base film 111 in FIG. 1) and the unstretched film 1 obtained in (1-1) (in FIG. 1) One surface of the second substrate film 112) is subjected to a discharge treatment using a corona treatment device (Kasuga Denki Co., Ltd.) under conditions of an output of 500 W, an electrode length of 1.35 m, and a conveyance speed of 5 m / min. did.
The discharge-treated surfaces of the stretched film 1 and the unstretched film 1 were bonded via a UV curable adhesive. In pasting, a commercially available laminator (GLM320R4 manufactured by Acobrands Japan) was used. The bonding pressure at this time was 1.1 MPa. In pasting, the entire surface was not pasted, but pasting was performed while leaving unbonded portions (corresponding to the unbonded portions 111G and 112G in FIG. 1) to be gripped for peeling. As the UV curable adhesive, product name “Aronix 7300K” manufactured by Toa Gosei Co., Ltd. was used, and the thickness of the adhesive layer was adjusted to 2 μm after curing.
The obtained paste is subjected to UV irradiation (metal halide lamp 500 mW / m ² , 2000 mJ / m ² ) from the unstretched film 1 side to cure the adhesive, and the adhesive layer (bonding member 122 in FIG. 1). To obtain a laminate. The storage modulus of the obtained adhesive layer was 3.9 GPa.

(1-4. Peeling process)
A water-repellent film having a structure schematically shown in FIG. 2 was produced by the following operation.
The laminate obtained in (1-3) was cut into a rectangle of 100 mm × 25 mm so that the longitudinal stretching direction of the stretched film 1 was the longitudinal direction.
The cut laminate is set in a tensile tester (“Tensile Testing Machine 5564” manufactured by Instron Japan Co., Ltd.) so that the longitudinal direction is the peeling direction, a chuck is attached to the non-bonded portion, and gripped, 180 ° Tension was performed at a speed of 300 mm / min so that T-type peeling was performed in the direction (each of the unstretched film 1 and the stretched film 1 was peeled by pulling them in the opposite direction in a state where the unstretched film 1 was bent at 90 °). . As a result of the tension, cohesive failure occurred in the layer of the stretched film 1, and a part of the stretched film 1 was peeled off from the remaining portion. Thus, the peeled portion of the stretched film 1 is obtained as a first water-repellent film (corresponding to the water-repellent film 211 in FIG. 2), and the remaining portion is obtained as a second water-repellent film (in FIG. 2). Obtained as a water-repellent film 202). In the obtained first and second water-repellent films, a fine concavo-convex structure was formed on the water-repellent surface, that is, the surface where cohesive failure occurred.

(1-5. Evaluation)
The contact angle of the water repellent surface of the obtained first and second water repellent films was evaluated.

[Example 2]
(2-1. Second base film: Production of unstretched film)
The peripheral speed R1 of the first cooling drum was 10.05 m / min, the peripheral speed R2 of the second cooling drum was 10.05 m / s, and the peripheral speed R3 of the third cooling drum was 9.98 m / min. The unstretched film 2 was obtained in the same manner as in the production of the unstretched film 1 of (1-1) in Example 1.

(2-2. First base film: production of stretched film)
In place of the unstretched film 1 obtained in (1-1), except that the unstretched film 2 obtained in (2-1) was used, the production of the stretched film 1 in (1-2) of Example 1 was carried out. Similarly, a stretched film 2 was obtained. It was 2580 MPa when the tensile elasticity modulus of the obtained stretched film 2 was measured.

(2-3. Manufacture and evaluation of laminate and water-repellent film)
Instead of the stretched film 1, the same procedure as in (1-3) to (1-5) of Example 1 except that the stretched film 2 obtained in (2-2) was used ((1-3) The unstretched film was evaluated by producing a laminate and a water-repellent film using the unstretched film 1 as in Example 1.

Example 3
(3-1. Bonding step: production of laminate)
On one surface of the stretched film 1 obtained in (1-2) of Example 1 and one surface of the unstretched film 1 obtained in (1-1) of Example 1, a corona treatment device (Kasuga Electric) The product was discharged under the conditions of an output of 500 W, an electrode length of 1.35 m, and a conveyance speed of 5 m / min.

  A small amount of a silane coupling agent (KBM-903 manufactured by Shin-Etsu Silicone Co., Ltd.) was placed in a sealed container, and the inside of the container was saturated with the vapor of the silane coupling agent. The stretched film 1 subjected to the discharge treatment was put therein, and the silane coupling agent was subjected to silane coupling treatment by a vapor treatment method while keeping the liquid level of the silane coupling agent in contact with the film for 15 minutes.

  On the other hand, a small amount of a silane coupling agent (KBM-403 manufactured by Shin-Etsu Silicone Co., Ltd.) was put in a sealed container, and the inside of the container was saturated with the vapor of the silane coupling agent. Here, the unstretched film 1 subjected to the discharge treatment was put, and the liquid surface of the silane coupling agent was kept at 25 ° C. for 15 minutes so that the liquid level of the silane coupling agent did not touch the film, and a silane coupling treatment by a vapor treatment method was performed.

  After aligning the surface of the stretched film 1 that has been subjected to the discharge treatment and silane coupling treatment and the surface of the unstretched film 1 that has been subjected to the discharge treatment and silane coupling treatment, pressure bonding using a laminator (GLM320R4 manufactured by Nippon GBC). Combined. The pressure bonding conditions were a pressure of 0.4 MPa and a temperature of 130 ° C. In pasting, the entire surface was not pasted, but pasting was performed leaving a non-bonded portion to be gripped for peeling. This obtained the laminated body.

(3-2. Peeling step)
The laminate obtained in (3-1) was cut into a rectangle of 100 mm × 25 mm so that the longitudinal stretching direction of the stretched film 1 was the longitudinal direction.
The cut laminate is set in a tensile tester (“Tensile Testing Machine 5564” manufactured by Instron Japan Co., Ltd.) so that the longitudinal direction is the peeling direction, a chuck is attached to the non-bonded portion, and gripped, 180 ° Tensioning was performed at a speed of 300 mm / min so as to peel the T-shape in the direction. As a result of the tension, cohesive failure occurred in the layer of the stretched film 1, and a part of the stretched film 1 was peeled off from the remaining portion. Thereby, the peeled part of the stretched film 1 was obtained as the first water-repellent film, and the remaining part was obtained as the second water-repellent film. In the obtained first and second water-repellent films, a fine concavo-convex structure was formed on the water-repellent surface, that is, the surface where cohesive failure occurred.

(3-3. Evaluation)
The contact angle of the water repellent surface of the obtained first and second water repellent films was evaluated.

[Reference Example 1]
The contact angle was measured on one side of the stretched film obtained in (1-2) of Example 1.

[Comparative Example 1]
As the stretched film, instead of the one obtained in (1-2), a biaxially stretched PET film (Cosmo Shine A4300 film thickness 100 μm manufactured by Toyobo Co., Ltd.) was used. In the same manner as (1-3) to (1-5), first and second water-repellent films were obtained and evaluated. However, the cut of the laminate in (1-3) was performed so that the longitudinal direction of the long biaxially stretched PET film before cutting coincided with the longitudinal direction of the cut laminate.

[Comparative Example 2]
(1-1) and (1-3) to (1) of Example 1 except that an unstretched polyvinyl alcohol film (thickness 80 μm) was used instead of the stretched film obtained in (1-2). In the same manner as in −5), first and second water-repellent films were obtained and evaluated. However, since the film which comprises a laminated body is a film without anisotropy, the cut of the laminated body in (1-3) was performed so that arbitrary arbitrary directions may become a longitudinal direction.

  Table 1 shows the outline and evaluation results of Examples and Comparative Examples.

  From the results in Table 1, it can be seen that a water-repellent film having high water repellency can be easily produced by the production method of the present invention.

DESCRIPTION OF SYMBOLS 100: Laminated body 111: 1st base film 111G: Non-bonding part 112: 2nd base film 112G: Non-bonding part 122: Bonding material 211: 1st water-repellent film 212: 1st Residue 202 of base film: second water repellent film

Claims (3)

The 1st surface of the 1st substrate film and the 1st surface of the 2nd substrate film are pasted together via a pasting material, and the pasting process which obtains a layered product, and the 1st base material Including a peeling step of peeling the film and the second base film to obtain a water-repellent film,
The first base film or the second base film is
It is a stretched film and has a tensile elastic modulus of 1600 MPa to 2600 MPa,
A method for producing a water-repellent film.   The method for producing a water-repellent film according to claim 1, wherein the first base film, the second base film, or both are films of an alicyclic structure-containing polymer resin.   The method for producing a water-repellent film according to claim 1 or 2, wherein the bonding material is an ultraviolet curable adhesive.