JP6337974B2 - Resin composition, film and display device - Google Patents

Description

  The present invention relates to a resin composition, a film, and a display device.

  In recent years, display devices such as a smartphone, a portable game machine, an audio player, and a tablet terminal are provided with a touch screen. A glass sheet is usually used on the surface of such a display device, but a plastic sheet as a substitute for the glass sheet has been developed from the viewpoint of weight reduction and workability of the display device. . For example, Patent Document 1 discloses a transparent sheet containing a methacrylic resin and a vinylidene fluoride resin as a plastic sheet as a substitute for a glass sheet, and this transparent sheet sufficiently satisfies transparency and relative dielectric constant. It is described.

  On the other hand, in recent years, display devices are used in various environments due to their high versatility, and therefore, they are required to have durability in harsh environments such as high temperature and high humidity.

JP2013-244604A

  The conventional transparent sheet as described in Patent Document 1 may become cloudy in a high temperature and high humidity environment such as a relative humidity of 90% at 60 ° C., and there is room for improvement in durability. .

（式中、Ｒ₁は水素原子又はメチル基を表し、Ｒ₁が水素原子のときＲ₂は炭素数１〜８のアルキル基を表し、Ｒ₁がメチル基のときＲ₂は炭素数２〜８のアルキル基を表す。）
で示される（メタ）アクリル酸エステルに由来する少なくとも１つの構造単位０.１〜５０質量％を含む共重合体。
〔３〕（メタ）アクリル樹脂の重量平均分子量（Ｍｗ）が、１２０,０００〜２５０,０００である〔１〕又は〔２〕に記載の樹脂組成物。
〔４〕フッ化ビニリデン樹脂が、ポリフッ化ビニリデンである〔１〕〜〔３〕のいずれか一項に記載の樹脂組成物。
〔５〕フッ化ビニリデン樹脂のメルトマスフローレイトが、０.１〜３０ｇ／１０分である〔１〕〜〔４〕のいずれか一項に記載の樹脂組成物。
〔６〕着色剤をさらに含む〔１〕〜〔５〕のいずれか一項に記載の樹脂組成物。
〔７〕〔１〕〜〔６〕のいずれか一項に記載の樹脂組成物から形成される層を含む膜。
〔８〕厚さが１００〜２０００μmである〔７〕に記載の膜。
〔９〕熱可塑性樹脂層をさらに含む〔７〕又は〔８〕に記載の膜。
〔１０〕樹脂組成物から形成される層の両面に熱可塑性樹脂層を含む〔７〕〜〔９〕のいずれか一項に記載の膜。
〔１１〕熱可塑性樹脂層が、（メタ）アクリル樹脂層又はポリカーボネート樹脂層である〔９〕又は〔１０〕に記載の膜。
〔１２〕熱可塑性樹脂層が、当該熱可塑性樹脂層を形成する全樹脂１００質量部当たり（メタ）アクリル樹脂を５０質量部以上含む樹脂から形成された層である〔９〕〜〔１１〕のいずれか一項に記載の膜。
〔１３〕熱可塑性樹脂層に含まれる（メタ）アクリル樹脂の重量平均分子量が、５０,０００〜３００,０００である〔１１〕又は〔１２〕に記載の膜。
〔１４〕熱可塑性樹脂層の厚さが、１０〜２００μmである〔９〕〜〔１３〕のいずれか一項記載の膜。
〔１５〕熱可塑性樹脂層のビカット軟化温度が、１００〜１６０℃である〔９〕〜〔１４〕のいずれか一項記載の膜。
〔１６〕（メタ）アクリル樹脂及びフッ化ビニリデン樹脂を含む膜であって、当該膜を６０℃で相対湿度９０％の環境下に１２０時間暴露したとき、当該膜のヘーズが２％以下であり、かつ誘電率が４.０以上である膜。
〔１７〕少なくとも一方の表面に、傷つき防止、反射防止、防眩及び指紋防止からなる群から選択される少なくとも一種の機能を付与するためのコーティング層をさらに有する〔７〕〜〔１６〕のいずれか一項に記載の膜。
〔１８〕〔７〕〜〔１７〕のいずれか一項に記載の膜を含む表示装置。
〔１９〕〔７〕〜〔１７〕のいずれか一項に記載の膜及び偏光板が積層された膜付き偏光板。
〔２０〕〔１９〕に記載の膜付き偏光板を含む表示装置。The present invention has been made in view of the above problems. That is, the present invention includes the inventions described in the following [1] to [20].
[1] A resin composition comprising a (meth) acrylic resin and a vinylidene fluoride resin,
Each of (meth) acrylic resin and vinylidene fluoride resin contains 35 to 45% by mass of (meth) acrylic resin and 65 to 55% by mass of vinylidene fluoride resin, respectively. The weight average molecular weight (Mw) is 100,000-300,000,
A resin composition in which at least one of the resins contained in the resin composition contains an alkali metal, and the alkali metal content is 50 ppm or less per 100 parts by mass of the total amount of all resins and alkali metals contained in the resin composition.
[2] The resin composition according to [1], wherein the (meth) acrylic resin is the following resin (a1) or (a2).
(A1) methyl methacrylate homopolymer,
(A2) 50-99.9 mass% of structural units derived from methyl methacrylate and the following formula (1)

(In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 8 carbon atoms when R ₁ is a hydrogen atom, and R ₂ represents _{2 to 2} carbon atoms when R ₁ is a methyl group. 8 represents an alkyl group.)
The copolymer containing 0.1-50 mass% of at least 1 structural unit derived from the (meth) acrylic acid ester shown by.
[3] The resin composition according to [1] or [2], wherein the (meth) acrylic resin has a weight average molecular weight (Mw) of 120,000 to 250,000.
[4] The resin composition according to any one of [1] to [3], wherein the vinylidene fluoride resin is polyvinylidene fluoride.
[5] The resin composition according to any one of [1] to [4], wherein the melt mass flow rate of the vinylidene fluoride resin is 0.1 to 30 g / 10 minutes.
[6] The resin composition according to any one of [1] to [5], further including a colorant.
[7] A film including a layer formed from the resin composition according to any one of [1] to [6].
[8] The film according to [7], having a thickness of 100 to 2000 μm.
[9] The film according to [7] or [8], further including a thermoplastic resin layer.
[10] The film according to any one of [7] to [9], which includes a thermoplastic resin layer on both sides of a layer formed from the resin composition.
[11] The film according to [9] or [10], wherein the thermoplastic resin layer is a (meth) acrylic resin layer or a polycarbonate resin layer.
[12] The thermoplastic resin layer is a layer formed of a resin containing 50 parts by mass or more of (meth) acrylic resin per 100 parts by mass of the total resin forming the thermoplastic resin layer. The membrane according to any one of the above.
[13] The film according to [11] or [12], wherein the (meth) acrylic resin contained in the thermoplastic resin layer has a weight average molecular weight of 50,000 to 300,000.
[14] The film according to any one of [9] to [13], wherein the thermoplastic resin layer has a thickness of 10 to 200 μm.
[15] The film according to any one of [9] to [14], wherein the Vicat softening temperature of the thermoplastic resin layer is 100 to 160 ° C.
[16] A film containing a (meth) acrylic resin and a vinylidene fluoride resin, and when the film is exposed to an environment of 90% relative humidity at 60 ° C. for 120 hours, the haze of the film is 2% or less. A film having a dielectric constant of 4.0 or more.
[17] Any of [7] to [16], further comprising a coating layer for imparting at least one function selected from the group consisting of scratch prevention, antireflection, antiglare and fingerprint prevention on at least one surface A membrane according to claim 1.
[18] A display device comprising the film according to any one of [7] to [17].
[19] A film-attached polarizing plate in which the film according to any one of [7] to [17] and a polarizing plate are laminated.
[20] A display device comprising the polarizing plate with a film according to [19].

  A layer formed from the resin composition of the present invention and a film including the layer can maintain transparency even when used for a long time in a high temperature and high humidity environment while having a high dielectric constant. Useful as a face plate.

It is the schematic of the manufacturing apparatus of the film | membrane of this invention used for the Example. It is a cross-sectional schematic diagram which shows the layer structural example of one preferable form of the liquid crystal display device which concerns on this invention.

<Resin composition>
The resin composition of the present invention is a resin composition containing at least a (meth) acrylic resin and a vinylidene fluoride resin, and the (meth) acrylic resin is used per 100% by mass of the total of the (meth) acrylic resin and the vinylidene fluoride resin. 35 to 45% by mass and 65 to 55% by mass of vinylidene fluoride resin are included, and the (meth) acrylic resin has a weight average molecular weight (Mw) of 100,000 to 300,000. Moreover, at least 1 type of resin contained in this resin composition contains an alkali metal, and content of an alkali metal is 50 ppm or less per 100 mass parts of total of all the resins and alkali metals contained in a resin composition. The present invention will be described below.

  This resin composition preferably contains 37 to 45% by mass of (meth) acrylic resin and 55 to 63% by mass of vinylidene fluoride resin, more preferably 100% by mass in total of (meth) acrylic resin and vinylidene fluoride resin. It contains 38 to 45% by mass of (meth) acrylic resin and 55 to 62% by mass of vinylidene fluoride resin, more preferably 38 to 43% by mass of (meth) acrylic resin and 57 to 62% by mass of vinylidene fluoride resin. The resin composition may contain other resins in addition to the (meth) acrylic resin and the vinylidene fluoride resin as long as the transparency is not impaired.

  At least one of the resins contained in these resin compositions contains an alkali metal. For example, when the (meth) acrylic resin or vinylidene fluoride resin is obtained by emulsion polymerization, the alkali metal can be sodium or potassium derived from the emulsifier remaining in the resin. The smaller the total content of alkali metals, the more preferable is a film containing a layer formed from a resin composition because the transparency tends not to be lowered when used for a long period of time in a high temperature and high humidity environment.

  The content of alkali metal is usually 50 ppm or less per 100 parts by mass of the total amount of all resins and alkali metals contained in the resin composition. The content of the alkali metal is preferably 30 ppm or less, more preferably 10 ppm or less, further preferably 1 ppm or less, and still more preferably substantially not contained. In order to make the content of the alkali metal in the resin within the above range, the amount of the compound containing the alkali metal is reduced during the polymerization of the resin, or the compound containing the alkali metal is increased by increasing the washing step after the polymerization. Just remove it. The alkali metal content can be determined by, for example, inductively coupled plasma mass spectrometry (ICP / MS). Examples of inductively coupled plasma mass spectrometry include sample pellets to be measured such as a high temperature ashing melting method, a high temperature ashing acid dissolution method, a Ca-added ashing acid dissolution method, a combustion absorption method, and a low temperature ashing acid dissolution method. The sample may be ashed by an appropriate method, dissolved in an acid, and the volume of the dissolved solution may be fixed, and the amount of alkali metal may be measured by inductively coupled plasma mass spectrometry.

((Meth) acrylic resin)
Examples of (meth) acrylic resins include homopolymers of (meth) acrylic monomers such as (meth) acrylic acid esters and (meth) acrylonitrile, copolymers of two or more (meth) acrylic monomers, acrylic monomers, Examples thereof include copolymers with monomers other than acrylic monomers. In the present specification, the term “(meth) acryl” means “acryl” or “methacryl”.

  As the (meth) acrylic resin, a methacrylic resin is preferably used from the viewpoint of having excellent hardness, weather resistance, transparency, and the like. A methacrylic resin is a polymer of a monomer mainly composed of a methacrylic acid ester (alkyl methacrylate). For example, a homopolymer of a methacrylic acid ester (polyalkyl methacrylate), a copolymer of two or more methacrylic acid esters And a copolymer of a monomer other than 50% by mass of a methacrylic acid ester and a monomer other than 50% by mass of a methacrylic acid ester. In the case of a copolymer of a methacrylic acid ester and a monomer other than the methacrylic acid ester, the methacrylic acid ester is preferably 70% by mass or more and the other monomer is 30% by mass with respect to the total amount of the monomers. More preferably, the methacrylic acid ester is 90% by mass or more and the other monomer is 10% by mass or less.

  Examples of monomers other than methacrylic acid esters include acrylic acid esters and monofunctional monomers having one polymerizable carbon-carbon double bond in the molecule.

  Monofunctional monomers include, for example, styrene monomers such as styrene, α-methylstyrene and vinyltoluene; alkenyl cyanides such as acrylonitrile and methacrylonitrile; acrylic acid; methacrylic acid; maleic anhydride; N-substituted Maleimide; and the like. Further, from the viewpoint of heat resistance, N-substituted maleimides such as phenylmaleimide, cyclohexylmaleimide and methylmaleimide may be copolymerized, or in a molecular chain (also referred to as a main skeleton or main chain in a polymer). A lactone ring structure, a glutaric anhydride structure, a glutarimide structure, or the like may be introduced.

More specifically, the (meth) acrylic resin is preferably the following resin (a1) or (a2).
(A1) A homopolymer of methyl methacrylate.
(A2) 50 to 99.9% by mass of structural units derived from methyl methacrylate and 0.1 to 50% by mass of at least one structural unit derived from a (meth) acrylic acid ester represented by the following formula (1) Containing copolymers. Here, the content of the structural unit can be calculated by analyzing the obtained polymer by pyrolysis gas chromatography and measuring the peak area corresponding to each monomer.

In formula (1), R ₁ represents a hydrogen atom or a methyl group, when R ₁ is a hydrogen atom R ₂ represents an alkyl group having 1 to 8 carbon atoms, when R ₁ is a methyl group R ₂ represents the number of carbon atoms Represents 2 to 8 alkyl groups. Examples of the alkyl group having 2 to 8 carbon atoms represented by R ₂ include an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Etc.

  The (meth) acrylic resin has a melt mass flow rate (hereinafter sometimes referred to as MFR) at 230 ° C. measured at a load of 3.8 kg of usually 0.1 to 20 g / 10 minutes, preferably 0.2. It is -5g / 10min, More preferably, it is 0.5-3g / 10min. If the MFR is too large, the strength of the resulting film tends to decrease, and if the MFR is too small, the film formability tends to decrease. The MFR can be measured in accordance with a method defined in JIS K 7210: 1999 “Plastic-thermoplastic melt mass flow rate (MFR) and melt volume flow rate (MVR) test methods”. This JIS stipulates that poly (methyl methacrylate) -based materials are measured at a temperature of 230 ° C. and a load of 3.80 kg (37.3 N).

  The (meth) acrylic resin preferably has a weight average molecular weight (hereinafter sometimes referred to as Mw) obtained by GPC measurement of 100,000 to 300,000, preferably 120,000 to 250,000. Is more preferable, and 150,000 to 200,000 is even more preferable. The obtained film tends to have higher transparency when exposed to a high-temperature and high-humidity environment such as 90% relative humidity at 60 ° C. as the Mw increases, but if it is too large, the film formability tends to decrease. It is in.

  From the viewpoint of heat resistance, the (meth) acrylic resin preferably has a Vicat softening temperature (hereinafter sometimes referred to as VST) of 90 ° C or higher, more preferably 100 ° C or higher, and 102 ° C or higher. More preferably. VST may be measured by the B50 method described in accordance with JIS K 7206: 1999. VST can be appropriately set by adjusting the type of monomer and its ratio.

  The (meth) acrylic resin can be prepared by polymerizing the above monomers by a known method such as suspension polymerization or bulk polymerization. In that case, MFR, Mw, VST, etc. can be adjusted to a preferable range by adding a suitable chain transfer agent. As the chain transfer agent, an appropriate commercial product can be used. What is necessary is just to determine the addition amount of a chain transfer agent suitably according to the kind of monomer, its ratio, the characteristic to obtain | require, etc. The obtained (meth) acrylic resin preferably has a low alkali metal content. The content of the alkali metal can be adjusted by reducing the amount of the compound containing the alkali metal during the polymerization, or increasing the washing step after the polymerization to remove the compound containing the alkali metal.

(Vinylidene fluoride resin)
The vinylidene fluoride resin is at least one selected from the group consisting of trifluoroethylene, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoroalkyl vinyl ether and ethylene from the viewpoint of the transparency of the resulting film. And a polymer obtained by copolymerizing vinylidene fluoride alone and a polymer obtained by polymerizing vinylidene fluoride alone (polyvinylidene fluoride), preferably polyvinylidene fluoride.

  The vinylidene fluoride resin has a melt mass flow rate (MFR) at 230 ° C. measured under a load of 3.8 kg is usually 0.1 to 30 g / 10 min, preferably 0.1 to 25 g / 10 min. The lower limit of MFR is more preferably 0.2 g / 10 minutes, and still more preferably 0.5 g / 10 minutes. The upper limit of MFR is more preferably 20 g / 10 minutes, further preferably 5 g / 10 minutes, and even more preferably 2 g / 10 minutes. If the MFR is too large, the transparency tends to decrease when the resulting film is used for a long time, and if the MFR is too small, the film formability tends to decrease.

  The vinylidene fluoride resin preferably has a weight average molecular weight (Mw) measured by GPC measurement of 100,000 to 500,000, more preferably 150,000 to 450,000, and 200,000 to 450. Is more preferably 350,000, and further preferably 350,000 to 450,000. The greater the Mw, the higher the transparency of the resulting film when exposed to a high temperature and high humidity environment with a relative humidity of 90% at 60 ° C., but if it is too large, the film formability tends to decrease. .

  The vinylidene fluoride resin is industrially produced by a suspension polymerization method or an emulsion polymerization method. The suspension polymerization method is carried out by using water as a medium, dispersing the monomer as droplets in the medium with a dispersant, and polymerizing an organic peroxide dissolved in the monomer as a polymerization initiator, A granular polymer of 100 to 300 μm is obtained. Suspension polymers are preferred because they have a simpler manufacturing process than powdered emulsions, have excellent powder handling properties, and do not contain an emulsifier or salting-out agent containing an alkali metal unlike emulsion polymers. The obtained vinylidene fluoride resin preferably has a low alkali metal content. The content of the alkali metal can be adjusted by reducing the amount of the compound containing the alkali metal during the polymerization, or increasing the washing step after the polymerization to remove the compound containing the alkali metal.

  A commercially available product may be used as the vinylidene fluoride resin. Examples of preferable commercially available products include K # Co., Ltd. "KF Polymer (registered trademark)" T # 1300, T # 1100, T # 1000, T # 850, W # 850, W # 1000, W # 1100 and W # 1300, “SOLEF (registered trademark)” 6012, 6010 and 6008 manufactured by Solvay.

(Other additives)
In the resin composition of the present invention, various commonly used additives may be added as long as the effects of the present invention are not impaired. Examples of additives include stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, foaming agents, lubricants, mold release agents, antistatic agents, flame retardants, mold release agents, polymerization inhibitors, and flame retardant aids. And coloring agents such as reinforcing agents, nucleating agents, and bluing agents.

  Examples of the colorant include a compound having an anthraquinone skeleton and a compound having a phthalocyanine skeleton. Among these, a compound having an anthraquinone skeleton is preferable from the viewpoint of heat resistance.

  When the resin composition includes a colorant, the content of the colorant in the resin composition can be appropriately selected according to the purpose, the type of the colorant, and the like. When using a bluing agent as a coloring agent, the content can be about 0.01-10 ppm per 100 mass parts of resin compositions. This content is preferably at least 0.01 ppm, more preferably at least 0.05 ppm, even more preferably at least 0.1 ppm, preferably at most 7 ppm, more preferably at most 5 ppm, even more preferably at most 4 ppm, even more preferably Is 3 ppm or less. Known bluing agents can be used as appropriate. For example, Macrolex (registered trademark) Blue RR (manufactured by Bayer), Macrolex (registered trademark) Blue 3R (manufactured by Bayer), respectively, under the trade name, Sumiplast (registered trademark) Viloet B (manufactured by Sumika Chemtex Co., Ltd.) and Polycinslen (registered trademark) Blue RLS (manufactured by Clariant), Diaresin Violet D, Diaresin Blue G, Diaresin Blue N (manufactured by Mitsubishi Chemical Corporation) Can be mentioned.

  These additives may be contained in a resin such as a (meth) acrylic resin or a vinylidene fluoride resin, or may be added during the melt-kneading of the (meth) acrylic resin and the vinylidene fluoride resin described later. It may be added after melt-kneading the (meth) acrylic resin and the vinylidene fluoride resin, or may be added when a film is formed using the resin composition.

  The resin composition of the present invention is usually obtained by kneading a (meth) acrylic resin and a vinylidene fluoride resin. Such kneading can be performed, for example, by a method including a step of melt-kneading at a shear rate of 10 to 1000 / second at a temperature of 150 to 350 ° C.

  If the temperature during melt kneading is less than 150 ° C., the resin may not melt. On the other hand, when the temperature at the time of melt kneading exceeds 350 ° C., the resin may be thermally decomposed. Furthermore, when the shear rate at the time of melt kneading is less than 10 / second, the kneading may not be sufficiently performed. On the other hand, if the shear rate during melt-kneading exceeds 1000 / second, the resin may be decomposed.

  In order to obtain a resin composition in which each component is more uniformly mixed, the melt-kneading is preferably performed at a temperature of 180 to 300 ° C, more preferably 200 to 300 ° C, preferably 20 to 700 / second, and more. Preferably, it is carried out at a shear rate of 30 to 500 / sec.

  As an apparatus used for melt kneading, a normal mixer or kneader can be used. Specific examples include a single-screw kneader, a twin-screw kneader, another-screw extruder, a Henschel mixer, a Banbury mixer, a kneader, and a roll mill. Further, when the shear rate is increased within the above range, a high shearing device or the like may be used.

<Membrane>
The film of the present invention preferably includes a layer formed from the resin composition of the present invention (hereinafter also referred to as A layer), may be a single layer film of A layer, Two or more layers including other layers may be used. The thickness of the film is preferably 500 to 2000 μm, more preferably 500 to 1500 μm, still more preferably 100 to 1500 μm, and even more preferably 100 to 1000 μm.

  This film preferably further includes a thermoplastic resin layer from the viewpoint of heat resistance, surface hardness, and adhesion to a coating layer described later. The thermoplastic resin layer can be laminated on at least one surface of the layer formed from the resin composition of the present invention, and may be laminated via another layer, but the resin composition of the present invention It is preferable that a thermoplastic resin layer is laminated in contact with the layer formed from the above. From the viewpoint of maintaining the shape of the film, it is preferable to include a thermoplastic resin layer on both sides of the A layer included in the film.

  The thickness of the thermoplastic resin layer is preferably 10 to 200 μm, and more preferably 50 to 150 μm. When the thermoplastic resin layers are included on both sides of the A layer included in the film, the thickness and composition of each thermoplastic resin layer may be the same or different from each other, but from the viewpoint of maintaining the shape of the film, It is preferable that they are substantially the same.

  The thermoplastic resin layer is formed from a thermoplastic resin. The thermoplastic resin preferably has a Vicat softening temperature of 100 to 160 ° C., more preferably 102 to 155 ° C., and 102 to 152 ° C. measured according to JIS K 7206: 1999. More preferably. The Vicat softening temperature of the thermoplastic resin is the Vicat softening temperature of the resin when the thermoplastic resin is made of one type of resin, and when the thermoplastic resin contains a plurality of resins, the Vicat softening temperature is formed of the plurality of resins. It is the Vicat softening temperature of a thermoplastic resin. Examples of the thermoplastic resin layer include a (meth) acrylic resin layer, a polycarbonate resin layer, and a cycloolefin resin layer. Preferably, it is a (meth) acrylic resin layer or a polycarbonate resin layer.

  The (meth) acrylic resin layer is formed of one or more types of (meth) acrylic resins or a composite resin of one or more types of (meth) acrylic resins and one or more types of thermoplastic resins other than (meth) acrylic resins. be able to. These (meth) acrylic resins preferably contain 50 parts by mass or more of (meth) acrylic resin per 100 parts by mass of the total resin forming the (meth) acrylic resin layer. The weight average molecular weight (Mw) of the (meth) acrylic resin contained in the (meth) acrylic resin layer is preferably 50,000 to 300,000, and more preferably 70,000 to 250,000. The (meth) acrylic resin contained in the (meth) acrylic resin layer may be the same as or different from the (meth) acrylic resin contained in the layer formed from the resin composition of the present invention. It is preferable that the thermoplastic resin layer does not substantially contain a vinylidene fluoride resin.

  As the thermoplastic resin other than the (meth) acrylic resin, a thermoplastic resin compatible with the (meth) acrylic resin is preferable. From the viewpoint of heat resistance, the thermoplastic resin other than (meth) acrylic resin preferably has a Vicat softening temperature of 115 ° C or higher, more preferably 117 ° C or higher, as measured in accordance with JIS K 7206: 1999. More preferably, the temperature is 120 ° C. or higher.

  When the thermoplastic resin is a (meth) acrylic resin, the pencil hardness of the thermoplastic resin layer is preferably HB or higher, more preferably F or higher, and even more preferably H or higher.

The polycarbonate resin layer can be formed of one or more types of polycarbonate resins or a composite resin of one or more types of polycarbonate resins and a thermoplastic resin other than one or more types of polycarbonate resins. These polycarbonate resins preferably have a melt volume rate (hereinafter also referred to as MVR) of ³ to 120 cm 3/10 minutes measured under conditions of a temperature of 300 ° C. and a load of 1.2 kg. MVR is more preferably in the 30~80cm ^3/10 min, more preferably 4~40cm ^3/10 min, deliberately preferably 10 to 40 cm ^3/10 min. If MVR is less than 3 cm ^3/10 min, because the flowability is decreased, and tends to be difficult by molding such as melt co-extrusion, there is the appearance failure occurs. Further, the MVR exceeds 120 cm ^3/10 min, mechanical properties such as strength of the polycarbonate resin layer tends to decrease. MVR can be measured under the condition of 300 ° C. under a load of 1.2 kg in accordance with JIS K 7210.

  The polycarbonate resin is a polymer obtained by, for example, a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonic ester such as diphenyl carbonate are reacted. As such, polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as bisphenol A) can be used.

  Examples of the dihydroxydiaryl compound include bisphenol 4-, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2, 2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3) -Tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone Sulfone, and the like.

  These may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be used in combination.

  Furthermore, the above dihydroxyaryl compound and a trivalent or higher phenol compound as shown below may be used in combination. Trihydric or higher phenols include phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene, 2,4,6-dimethyl-2,4,6-tri- (4 -Hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2-bis- [4 4- (4,4'-dihydroxydiphenyl) -cyclohexyl] -propane and the like.

  When the polycarbonate resin layer is formed from a composite resin of one or more types of polycarbonate resin and one or more types of thermoplastic resin, the thermoplastic resin other than the polycarbonate resin is blended within a range that does not impair the transparency. can do. As this thermoplastic resin, for example, a (meth) acrylic resin compatible with a polycarbonate resin is preferable, and a methacrylic resin having an aromatic ring or a cycloolefin in its structure is more preferable. When the polycarbonate resin contains such a tacryl resin, the surface hardness of the obtained polycarbonate resin layer can be made higher than when the polycarbonate resin is formed from the polycarbonate resin alone.

  Examples of polycarbonate resins other than the above polycarbonate resins include polycarbonates synthesized from isosorbite and aromatic diols. For example, “DURABIO (registered trademark)” manufactured by Mitsubishi Chemical Corporation may be mentioned.

  The polycarbonate resin includes a release agent, an ultraviolet absorber, a dye, a pigment, a polymerization inhibitor, an antioxidant, a flame retardant, a reinforcing agent and other additives, a polymer other than the polycarbonate resin, and the like. You may make it contain in the range which does not impair an effect.

  A commercially available product may be used as the polycarbonate resin. Examples of commercial products include 301-4, 301-10, 301-15, 301-22, 301-30, 301-40, SD2221W, SD2201W of “Caliber (registered trademark)” manufactured by Sumika Stylon Polycarbonate Co., Ltd. , TR2201 and the like.

  The film of the present invention is transparent when visually observed, and the total light transmittance (Tt) measured in accordance with JIS K7361-1: 1997 is preferably 88% or more, more preferably 90% or more. It is. The total light transmittance of the film maintains this range even when the film is exposed to an environment of 90% relative humidity at 60 ° C. for 120 hours.

  The film of the present invention contains a (meth) acrylic resin and a vinylidene fluoride resin. When the film of the present invention is exposed to an environment of 90% relative humidity at 60 ° C. for 120 hours, the haze (haze value) measured in accordance with JIS K7136: 2000 may be 2.0% or less. The yellowness (Yellow Index: YI value) can be 1.5 or less. The haze is more preferably 1.8% or less, and still more preferably 1.5% or less. The yellowness can be calculated as a YI value according to JIS Z 8722: 2009. It is preferably 1.4 or less, more preferably 1.2 or less than the vinylidene fluoride resin.

  Further, the membrane of the present invention is in accordance with JIS K 6911: 1995, left at 23 ° C. in an environment with a relative humidity of 50% for 24 hours, and measured in this environment at 3 V and 100 kHz measured by the automatic equilibrium bridge method. The dielectric constant is usually 3.5 or more, preferably 4.0 or more. A commercially available device may be used for the measurement, and for example, measurement can be performed with “precision LCR meter HP4284A” manufactured by Agilent Technologies.

  The A layer contained in the film of the present invention can be produced by molding the above resin composition of the present invention by, for example, a melt extrusion molding method, a solution casting film forming method, a hot press method, an injection molding method or the like. Among them, the injection molding method and the melt extrusion method are preferable, and the melt extrusion method is more preferable.

  When the film of the present invention further includes a thermoplastic resin layer, the A layer obtained by molding the resin composition of the present invention by the above molding and the separately formed thermoplastic resin layer are bonded, for example, via an adhesive or an adhesive. May be manufactured by laminating and laminating the resin composition of the present invention and a thermoplastic resin such as a (meth) acrylic resin and a polycarbonate resin. preferable. Thus, the film manufactured by melt coextrusion molding usually tends to be secondary molded as compared with the film manufactured by bonding.

  In melt coextrusion molding, for example, the resin composition of the present invention and a thermoplastic resin such as a (meth) acrylic resin and a polycarbonate resin are separately fed into two or three uniaxial or biaxial extruders. Then, after the respective melt-kneading, the layer formed from the resin composition of the present invention and the thermoplastic resin layer are laminated and integrated through a feed block die, a multi-manifold die or the like, and extruded. The obtained film is preferably cooled and solidified by, for example, a roll unit.

  The film of the present invention preferably further has a coating layer on at least one surface for imparting at least one function selected from the group consisting of scratch prevention, antireflection, antiglare and fingerprint prevention. As a coating layer, the cured film described in Unexamined-Japanese-Patent No. 2013-86273 can be used, for example.

  The thickness of the coating layer is preferably 1 to 100 μm, more preferably 3 to 80 μm, and even more preferably 5 to 70 μm. If it is thinner than 1 μm, it is difficult to express its function, and if it is thicker than 100 μm, the coating layer may be cracked.

  If necessary, the surface of the coating layer may be subjected to antireflection treatment by a coating method, a sputtering method, a vacuum deposition method, or the like. In addition, for the purpose of imparting an antireflection effect, a separately prepared antireflection sheet may be bonded to one side or both sides.

When the layer formed from the resin composition of the present invention is abbreviated as A layer, the thermoplastic resin layer is abbreviated as B layer, and the coating layer is abbreviated as C layer, examples of the layer structure of the film of the present invention include the following (1) to ( 12). However, considering the adhesion and scratch resistance between the coating layer and the film, there is a thermoplastic resin layer on the surface, and there is little change in shape when exposed to a high temperature and high humidity environment of 90% relative humidity at 60 ° C. In view of lack, the configuration of (3), (4), (10) or (12) is preferable, and the configuration of (3) or (10) is more preferable.
(1) A layer (2) A layer / B layer (3) B layer / A layer / B layer (4) B layer / A layer / B layer / A layer / B layer (5) A layer / C layer ( 6) C layer / A layer / C layer (7) A layer / B layer / C layer (8) C layer / A layer / B layer / C layer (9) B layer / A layer / B layer / C layer ( 10) C layer / B layer / A layer / B layer / C layer (11) B layer / A layer / B layer / A layer / B layer / C layer (12) C layer / B layer / A layer / B layer / A layer / B layer / C layer

<Transparent conductive sheet>
A transparent conductive sheet can be obtained by forming a transparent conductive film on at least one side of the film of the present invention.

  As a method of forming a transparent conductive film on the surface of the film of the present invention, a method of directly forming a transparent conductive film on the surface of the film of the present invention may be used, or a plastic film on which a transparent conductive film has been previously formed is used. It may be a method of forming a transparent conductive film by laminating on the surface of the film of the invention.

  The film base of the plastic film on which the transparent conductive film is formed in advance may be a transparent film that can form a transparent conductive film. For example, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, An acrylic resin, polyamide, a mixture or laminate thereof can be exemplified. Also, before forming the transparent conductive film, it is effective to coat the film for the purpose of improving the surface hardness, preventing Newton's ring, and imparting antistatic properties.

  The method of laminating a film, on which a transparent conductive film has been previously formed, on the surface of the film of the present invention may be any method as long as it is free from bubbles and can provide a uniform and transparent sheet. A method of laminating using an adhesive that is cured by normal temperature, heating, ultraviolet light, or visible light may be used, or a transparent adhesive tape may be used for bonding.

  As a method for forming a transparent conductive film, a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, a spray method, and the like are known, and these methods are appropriately used depending on a required film thickness. Can do.

  In the case of the sputtering method, for example, a normal sputtering method using an oxide target, a reactive sputtering method using a metal target, or the like is used. At this time, oxygen, nitrogen, or the like may be introduced as a reactive gas, or means such as ozone addition, plasma irradiation, or ion assist may be used in combination. If necessary, a bias such as direct current, alternating current, and high frequency may be applied to the substrate. The transparent conductive metal oxide used for the transparent conductive film includes indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite. An oxide etc. are mentioned. Of these, indium-tin composite oxide (ITO) is preferable from the viewpoints of environmental stability and circuit processability.

  As a method of forming a transparent conductive film, it is formed by applying a coating agent containing various conductive polymers capable of forming a transparent conductive film and curing it by irradiating with ionizing radiation such as heat or ultraviolet rays. The method of making it apply is also applicable. As the conductive polymer, polythiophene, polyaniline, polypyrrole, and the like are known, and these conductive polymers can be used.

  The thickness of the transparent conductive film is not particularly limited, but when a transparent conductive metal oxide is used, it is usually 50 to 2000 mm, preferably 70 to 000 mm. If it is this range, it will be excellent in both electroconductivity and transparency.

  The thickness of the transparent conductive sheet is not particularly limited, and an optimum thickness can be selected according to the demand for the product specifications of the display.

<Touch sensor panel>
The film | membrane and transparent conductive sheet of this invention can be used suitably as transparent electrodes, such as a display panel face plate and a touch screen. Specifically, the film of the present invention can be used as a touch screen window sheet, and the transparent conductive sheet can be used as an electrode substrate for a resistive film type or capacitive type touch screen. An external touch sensor panel having a touch screen function can be obtained by arranging the touch screen on the front surface of a liquid crystal display, an organic EL display, or the like.

<Display device>
The film of the present invention can be applied to flat panel display devices other than liquid crystal displays and liquid crystal display devices. For example, the film can be used as a front plate disposed on the outermost surface of the display device. Examples of the flat panel display device other than the liquid crystal display device include an organic EL display device, a plasma display display device, a field emission display (FED), a SED type flat display, and electronic paper. For example, when applied to a liquid crystal display device, the film of the present invention can be laminated on a polarizing plate via an optical adhesive such as an adhesive and a pressure-sensitive adhesive. As the adhesive or pressure-sensitive adhesive, a known one may be used as appropriate.

  FIG. 2 is a schematic cross-sectional view showing an example of a liquid crystal display device to which the film of the present invention is applied. The film 10 of the present invention can be laminated on the polarizing plate 11 via an optical adhesive, and this laminate can be disposed on the viewing side of the liquid crystal cell 13. A polarizing plate is usually disposed on the back side of the liquid crystal cell. The liquid crystal display device 15 is composed of such members. FIG. 2 is an example of a liquid crystal display device and is not limited to this configuration.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these Examples.

In the examples, Vicat softening temperature, alkali metal content, MFR, MVR, total light transmittance, haze, and YI value were measured by the following methods, respectively.
The Vicat softening temperature was measured in accordance with the B50 method defined in JIS K 7206: 1999 “Plastic—Thermoplastic—Vicat Softening Temperature (VST) Test Method”. The Vicat softening temperature was measured with a heat distortion tester ["148-6 continuous type" manufactured by Yasuda Seiki Seisakusho Co., Ltd.]. The test piece at that time was measured by press-molding each raw material to a thickness of 3 mm.
The alkali metal content was measured by inductively coupled plasma mass spectrometry.
The MFR was measured in accordance with the method defined in JIS K 7210: 1999 “Testing methods for plastic-thermoplastic melt mass flow rate (MFR) and melt volume flow rate (MVR)”. This JIS stipulates that poly (methyl methacrylate) -based materials are measured at a temperature of 230 ° C. and a load of 3.80 kg (37.3 N).
MVR was measured with a “semi-auto melt indexer 2A” manufactured by Toyo Seiki Seisakusho Co., Ltd., which conforms to JIS K 7210, under a load of 1.2 kg and at 300 ° C.
Haze transmittance meter based on JIS K 7361-1: 1997 "Plastics-Test method of total light transmittance of transparent materials-Part 1: Single beam method" [Murakami Color Co., Ltd.] Measurement was performed with “HR-100” manufactured by Technical Research Institute.
The YI value was measured with “Spectrophotometer SQ2000” manufactured by Nippon Denshoku Industries Co., Ltd.

(Production Example 1)
98.5 parts by weight of methyl methacrylate and 1.5 parts by weight of methyl acrylate were mixed, and 0.16 parts by weight of a chain transfer agent (octyl mercaptan) and 0.1 part by weight of a release agent (stearyl alcohol) were added. A mass mixture was obtained. Further, 0.036 parts by mass of a polymerization initiator [1,1-di (tert-butylperoxy) 3,3,5-trimethylcyclohexane] was added to 100 parts by mass of methyl methacrylate to obtain an initiator mixed solution. Continuously fed to the fully mixed polymerization reactor so that the flow ratio of the monomer mixture to the initiator mixture was 8.8: 1, the average residence time was 20 minutes, the temperature was 175 ° C, and the average polymerization rate was 54%. Until partial polymerization was obtained. The resulting partially polymerized product is heated to 200 ° C. and led to a vented devolatilizing extruder, and unreacted monomers are devolatilized from the vent at 240 ° C., and the polymer after devolatilization is extruded in a molten state. After cooling with water, it was cut to obtain a pellet-shaped methacrylic resin (i).

  The obtained pellet-like methacrylic resin composition was analyzed by pyrolysis gas chromatography under the following conditions, and each peak area corresponding to methyl methacrylate and acrylate ester was measured. As a result, in the methacrylic resin (i), the structural unit derived from methyl methacrylate was 97.5% by mass, and the structural unit derived from methyl acrylate was 2.5% by mass.

(Pyrolysis conditions)
Sample preparation: A methacrylic resin composition was precisely weighed (standard 2-3 mg), placed in the center of a bowl-shaped metal cell, the metal cell was folded, and both ends were lightly pressed with pliers and sealed.
Pyrolysis device: CURIE POINT PYROLYZER JHP-22 (manufactured by Nippon Analytical Industries, Ltd.)
Metal cell: Pyrofoil F590 (Nippon Analytical Industrial Co., Ltd.)
Thermostatic bath set temperature: 200 ° C
Set temperature of heat insulation pipe: 250 ℃
Thermal decomposition temperature: 590 ° C
Thermal decomposition time: 5 seconds

(Gas chromatography analysis conditions)
Gas chromatography analyzer: GC-14B (manufactured by Shimadzu Corporation)
Detection method: FID
Column: 7G 3.2 m × 3.1 mmφ (manufactured by Shimadzu Corporation)
Filler: FAL-M (manufactured by Shimadzu Corporation)
Carrier gas: Air / N2 / H2 = 50/100/50 (kPa), 80 ml / min Column heating conditions: Hold at 100 ° C. for 15 minutes, then increase to 150 ° C. at 10 ° C./min. Hold for 14 minutes INJ temperature: 200 ° C
DET temperature: 200 ° C

The peak area (a ₁ ) corresponding to methyl methacrylate and acrylic acid detected when the methacrylic resin composition is pyrolyzed under the above pyrolysis conditions and the generated decomposition product is measured under the above gas chromatography analysis conditions The peak area (b ₁ ) corresponding to the ester was measured. Then, to determine the peak area ratio of these peak areas _{A (= b 1 / a 1} ). On the other hand, a standard product of a methacrylic resin having a weight ratio of acrylic ester units to methyl methacrylate units of W ₀ (known) is pyrolyzed under the above pyrolysis conditions, and the generated decomposition product is subjected to the above gas chromatography analysis conditions. The peak area (a ₀ ) corresponding to methyl methacrylate and the peak area (b ₀ ) corresponding to acrylate detected when the measurement is performed are measured, and the peak area ratio A ₀ (= b ₀ ) is measured from these peak areas. / A ₀ ). Then, the factor f (= W ₀ / A ₀ ) was determined from the peak area ratio A ₀ and the weight ratio W ₀ .
By multiplying the peak area ratio A by the factor f, a weight ratio W of acrylate units to methyl methacrylate units in the copolymer contained in the methacrylic resin composition is obtained, and from the weight ratio W, methacrylic acid is obtained. The ratio (mass%) of the methyl methacrylate unit to the total of the methyl unit and the acrylate unit and the ratio (mass%) of the acrylate unit to the total were calculated.

(Production Example 2)
A pellet-like methacrylic resin (ii) was prepared in the same manner as in Production Example 1 except that 95.0 parts by mass of methyl methacrylate, 5.0 parts by mass of methyl acrylate, and 0.08 parts by mass of the chain transfer agent were changed. And the content of the structural unit was measured. In the methacrylic resin (ii), the structural unit derived from methyl methacrylate was 94.7% by mass, and the structural unit derived from methyl acrylate was 5.3% by mass.

(Production Example 3)
A pellet-like methacrylic resin (iii) was prepared in the same manner as in Production Example 1 except that 97.7 parts by mass of methyl methacrylate, 2.3 parts by mass of methyl acrylate, and 0.05 part by mass of the chain transfer agent were changed. And the content of the structural unit was measured. In the methacrylic resin (iii), the structural unit derived from methyl methacrylate was 97.0% by mass, and the structural unit derived from methyl acrylate was 3.0% by mass.

  Table 1 shows the (meth) acrylic resins used in the examples and their physical properties. Methacrylic resins (i) to (iii) are methacrylic resins obtained in the above production examples, and Altglass (registered trademark) HT121 is an acrylic resin used for the thermoplastic resin layer. In addition, "MA" in a table | surface represents the content rate of the structural unit derived from the methyl acrylate in a methacryl resin.

The weight average molecular weight (Mw) of the (meth) acrylic resin was measured by gel permeation chromatography (GPC). To create a GPC calibration curve, use a methacrylic resin made by Showa Denko KK with a narrow molecular weight distribution and known molecular weight as a standard reagent, create a calibration curve from the elution time and molecular weight, and calculate the weight of each resin composition. Average molecular weight was measured. Specifically, 40 mg of resin was dissolved in 20 ml of tetrahydrofuran (THF) solvent to prepare a measurement sample. For the measuring device, two columns “TSKgel SuperHM-H”, which is a column made by Tosoh Corporation, and one “SuperH2500” were installed in series, and a detector employing an RI detector was used. . The measured molecular weight distribution curve was fitted using the normal distribution function by taking the logarithm of the molecular weight on the horizontal axis and fitting using the normal distribution function of the following equation.

  In Examples, “Regisfi (registered trademark) R-200” manufactured by Denka Co., Ltd. was used as the thermoplastic resin other than the (meth) acrylic resin used for forming the thermoplastic resin layer. This resin had a Vicat softening temperature of 132 ° C. and an MFR of 1.8 g / 10 min.

  Table 2 shows the vinylidene fluoride resins used in the examples and their physical properties.

  The weight average molecular weight (Mw) of vinylidene fluoride was measured by GPC. To prepare a GPC calibration curve, polystyrene was used as a standard reagent, a calibration curve was created from the elution time and molecular weight, and the weight average molecular weight of each resin was measured. Specifically, 40 mg of resin was dissolved in 20 ml of N-methylpyrrolidone (NMP) solvent to prepare a measurement sample. As the measuring device, two columns “TSKgel SuperHM-H” made by Tosoh Corporation and one “SuperH2500” were installed in series, and a detector employing an RI detector was used. .

In the examples, the following were used as the polycarbonate resin used for the thermoplastic resin layer. Both are products made by Sumika Stylon Polycarbonate.
Caliber 301-15: MVR10cm ^3/10 min, and Mw38,500 resin.
Caliber 301-22: MVR22cm ^3/10 min, and Mw35,000 resin.
Caliber 301-30: MVR ³⁰ cm 3/10 min and Mw 32,200 resin.
Caliber SD2201W: MVR118cm ^3/10 min, and Mw13,600 resin.

  The weight average molecular weight of the polycarbonate resin was measured by gel permeation chromatography (GPC). To create a GPC calibration curve, use a methacrylic resin made by Showa Denko KK with a narrow molecular weight distribution and known molecular weight as a standard reagent, create a calibration curve from the elution time and molecular weight, and calculate the weight of each resin composition. Average molecular weight was measured. Specifically, 40 mg of resin was dissolved in 20 ml of tetrahydrofuran (THF) solvent to prepare a measurement sample. As the measuring device, two columns “TSKgel SuperHM-H” made by Tosoh Corporation and one “SuperH2500” were installed in series, and a detector employing an RI detector was used. .

(Production Example 4)
In order to turn the bluing agent into a master batch (MB), (meth) acrylic resin and colorant are dry blended in the proportions shown in Table 3 and set with a 40 mmφ single screw extruder (manufactured by Tanabe Plastic Machinery Co., Ltd.). It was melt-mixed at a temperature of 250 to 260 ° C. to obtain colored master batch pellets. As the colorant, a bluing agent (“Sumiplast (registered trademark) Violet B” manufactured by Sumika Chemtex Co., Ltd.) was used.

(Examples 1-5 and Comparative Examples 1-6)
When the layer formed from the resin composition of the present invention is the A layer and the thermoplastic resin layer is the B layer, a film represented by B layer / A layer / B layer was produced as follows.
First, as a material for forming the A layer, (meth) acrylic resin, vinylidene fluoride resin, and the master batch pellet prepared in Production Example 1 are mixed in the combinations and proportions shown in Table 4, and the resin composition of the present invention is mixed. Obtained. Next, the resin composition was 65 mmφ single screw extruder 1 and 3 [manufactured by Toshiba Machine Co., Ltd.], and 100 parts by weight of methacrylic resin (i) as a layer B forming material was 45 mmφ single screw extruder 2 [Hitachi Zosen Corporation]. Made] and melted respectively. Subsequently, these are laminated so as to have a structure represented by the above-mentioned B layer / A layer / B layer through a feed block 4 (manufactured by Hitachi Zosen) having a set temperature of 250 to 270 ° C., and a multi-manifold type Extruded from a die 5 [manufactured by Hitachi Zosen Co., Ltd., 2 types, 3 layers distribution], a film-like molten resin 6 was obtained. Then, the obtained film-like molten resin 6 is sandwiched between the first cooling roll 7 and the second cooling roll 8 that are arranged to face each other, and then wound around the second roll 8 while the second roll 8 and the third roll. 9, the film was wound around a third cooling roll 9, molded and cooled, and a film 10 having a three-layer structure in which the thickness of each layer is as shown in Table 4 was obtained. All of the obtained films 10 had a total film thickness of 800 μm, and were visually transparent when observed visually.

  Table 5 shows calculated values obtained from Tables 1 to 4 for the amount of alkali metal (Na + K) contained in the A layer.

  Table 5 shows the results of measuring the dielectric constant of each film with a precision LCR meter HP4284A (manufactured by Agilent Technologies) in accordance with JIS K 6911: 1995. The dielectric constant is a numerical value at 3 kHz and 100 kHz measured by the automatic equilibrium bridge method in which the test sample (film) is allowed to stand in an environment of 50% relative humidity at 23 ° C. for 24 hours.

  Further, the durability test was performed by leaving the obtained film in a constant temperature and humidity oven at 60 ° C. and 90% absolute humidity for 120 hours. Table 5 shows the haze value (Haze) measured according to JIS K7136: 2000 and the total light transmittance (Tt) measured according to JIS K7361-: 19971 for the films before and after the durability test. .

(Examples 6 to 8)
In Example 4, a film was obtained in the same manner as in Example 4 except that the composition of the B layer was changed to the resin composition in the ratio described in Table 6. Table 7 shows the dielectric constant and durability test results of the obtained film measured in the same manner as in Example 4.

(Comparative Examples 7 and 8)
A resin 4 pellet as a vinylidene fluoride resin and a methacrylic resin (iii) pellet as a (meth) acrylic resin were uniformly mixed in the proportions shown in Table 8, respectively, and then a 20 mm single screw extruder (laboplast) Using a mill, manufactured by Toyo Seiki Seisakusho, kneaded at 250 ° C., blended pellets were obtained. A film having a thickness of 800 μm was obtained by press molding at 220 ° C. using this pellet. Table 8 also shows the results of durability tests of the obtained membranes measured in the same manner as in Example 1.

(Example 9 and Comparative Example 9)
A resin 1 pellet as a vinylidene fluoride resin and a methacrylic resin (i) pellet as a (meth) acrylic resin were uniformly mixed in the proportions shown in Table 9, respectively, and then a 20 mm single screw extruder (laboplast mill) , Manufactured by Toyo Seiki Seisakusho Co., Ltd.) to obtain blend pellets. A film having a thickness of 800 μm was obtained by press molding at 220 ° C. using this pellet. Table 9 also shows the dielectric constant and durability test results of the obtained film measured in the same manner as in Example 1.

(Example 10)
By using the films obtained in Examples 1 to 9 as a front plate (display window sheet), a display device having the configuration shown in the cross-sectional view of FIG. 2 can be produced.

(Examples 11 to 18)
When the layer formed from the resin composition is the A layer and the thermoplastic resin layer is the B layer, a film represented by B layer / A layer / B layer was produced as follows.
First, as a material for forming the A layer, (meth) acrylic resin, vinylidene fluoride resin, and the master batch pellet prepared in Production Example 1 were mixed in the combinations and proportions shown in Table 10 to obtain the resin composition of the present invention. . The processing method was the same as in Examples 1 to 5 except that the resin composition was different.

  Table 11 shows the calculated values obtained from Tables 1 and 3 for the amount of alkali metal (Na + K) contained in layer A of the obtained film and the dielectric constant measured by the same method as described above. Table 11 shows the results of an endurance test in which the obtained film was left in a constant temperature and humidity oven at 60 ° C. and 90% absolute humidity for 120 hours.

(Examples 19 to 22)
Membranes were produced in the same manner as in Examples 1 to 5 except that polycarbonate resin was used for the B layer. Table 12 shows the composition and ratio of the resin in the A layer and the B layer.

  Table 13 shows the calculated values obtained from Tables 1 and 3 for the amount of alkali metal (Na + K) contained in the A layer of the obtained film and the dielectric constant measured by the same method as described above. Table 13 shows the results of an endurance test in which the obtained film was left in a constant temperature and humidity oven at 60 ° C. and 90% absolute humidity for 120 hours.

  Furthermore, Table 14 shows the results of measuring the falling ball strength of the obtained film. The falling ball strength was measured by dropping a 25 g iron ball from a predetermined height and measuring the height at which the film breaks.

  The layer formed from the resin composition of the present invention and the film of the present invention including the layer can maintain transparency even when used for a long time in a high temperature and high humidity environment while having a high dielectric constant. It is useful as a front plate in display devices such as portable game machines, audio players and tablet terminals.

1 Single screw extruder (extrudes a melt of (meth) acrylic resin)
2 Single screw extruder (extrudes the melt of the resin composition of the present invention)
3 Single screw extruder (extrudes a melt of (meth) acrylic resin)
4 Feed block 5 Multi-manifold die 6 Film-like molten resin 7 First cooling roll 8 Second cooling roll 9 Third cooling roll 10 Film 11 Polarizing plate 12 Optical adhesive layer 13 Liquid crystal cell 15 Liquid crystal display device

Claims (20)

A resin composition comprising a (meth) acrylic resin and a vinylidene fluoride resin,
Each of (meth) acrylic resin and vinylidene fluoride resin contains 35 to 45% by mass of (meth) acrylic resin and 65 to 55% by mass of vinylidene fluoride resin, respectively. The weight average molecular weight (Mw) is 100,000-300,000,
A resin composition in which at least one of the resins contained in the resin composition contains an alkali metal, and the alkali metal content is 50 ppm or less per 100 parts by mass of the total amount of all resins and alkali metals contained in the resin composition. The resin composition according to claim 1, wherein the (meth) acrylic resin is the following resin (a1) or (a2).
(A1) methyl methacrylate homopolymer,
(A2) 50-99.9 mass% of structural units derived from methyl methacrylate and the following formula (1)

(In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 8 carbon atoms when R ₁ is a hydrogen atom, and R ₂ represents _{2 to 2} carbon atoms when R ₁ is a methyl group. 8 represents an alkyl group.)
The copolymer containing 0.1-50 mass% of at least 1 structural unit derived from the (meth) acrylic acid ester shown by.   The resin composition according to claim 1 or 2, wherein the (meth) acrylic resin has a weight average molecular weight (Mw) of 120,000 to 250,000.   The resin composition according to any one of claims 1 to 3, wherein the vinylidene fluoride resin is polyvinylidene fluoride. The resin composition as described in any one of Claims 1-4 whose melt mass flow rate in 230 degreeC measured by the 3.8kg load of vinylidene fluoride resin is 0.1-30 g / 10min.   The resin composition according to any one of claims 1 to 5, further comprising a colorant.   The film | membrane containing the layer formed from the resin composition as described in any one of Claims 1-6.   The film according to claim 7, which has a thickness of 100 to 2000 µm.   The film according to claim 7 or 8, further comprising a thermoplastic resin layer.   The film | membrane as described in any one of Claims 7-9 which contains a thermoplastic resin layer on both surfaces of the layer formed from a resin composition.   The film according to claim 9 or 10, wherein the thermoplastic resin layer is a (meth) acrylic resin layer or a polycarbonate resin layer.   The thermoplastic resin layer is a layer formed from a resin containing 50 parts by mass or more of (meth) acrylic resin per 100 parts by mass of the total resin forming the thermoplastic resin layer. The membrane described.   The film according to claim 11 or 12, wherein the (meth) acrylic resin contained in the thermoplastic resin layer has a weight average molecular weight of 50,000 to 300,000.   The film according to any one of claims 9 to 13, wherein the thermoplastic resin layer has a thickness of 10 to 200 µm.   The film according to any one of claims 9 to 14, wherein a Vicat softening temperature of the thermoplastic resin layer is 100 to 160 ° C. A film containing a (meth) acrylic resin and a vinylidene fluoride resin, and when the film is exposed to an environment of 90% relative humidity at 60 ° C. for 120 hours, the haze of the film is 2% or less and dielectric A film | membrane as described in any one of Claims 7-15 whose rate is 4.0 or more.   17. The coating layer according to claim 7, further comprising a coating layer for imparting at least one function selected from the group consisting of anti-scratching, anti-reflection, anti-glare and anti-fingerprint on at least one surface. Membrane.   The display apparatus containing the film | membrane as described in any one of Claims 7-17.   The polarizing plate with a film | membrane with which the film | membrane and polarizing plate as described in any one of Claims 7-17 were laminated | stacked.   A display device comprising the polarizing plate with a film according to claim 19.

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