Membrane, method for manufacturing the membrane, and use of the membrane

Abstract

The present invention discloses a film, a manufacturing method thereof, and uses thereof. The film is a film containing a non-fluororesin and a fluororesin, and the content of the fluororesin is 0.1 to 20.0% by mass relative to the total mass of the non-fluororesin, and the fluorine atom content of the fluororesin is 50% by mass or less.

Description

Technical Field

[0001] The present invention relates to a film, a method for manufacturing the film, and uses of the film. Background Art

[0002] Films used as release films, films for building structures, agricultural films, films for protecting wind power generation blades, decorative films, packaging films, automotive paint protection films, films for communication towers, or films for aircraft, etc., are often used for various purposes as covering films, and these covering films are widely used to provide surface protection. In the agricultural field, agricultural covering materials are required for soil heat preservation and moisture retention, preventing the loss of nutrients in the soil, maintaining the granular structure of the soil, etc. Agricultural covering materials include, for example, agricultural films such as transparent synthetic resin films for the roofs or side walls of agricultural greenhouses for plant cultivation, and are a kind of product for measures such as protecting plant water loss in agricultural production. With the progress of science and technology, the requirements for agricultural films are getting higher and higher.

[0003] Currently, commonly used agricultural films include, for example, polyethylene films made of polyethylene and polyvinyl chloride films made of polyvinyl chloride. For example, Patent Document 1 proposes an agricultural film formed from a resin composition containing polyvinyl chloride as a main component.

[0004] In addition, fluororesin films have good weather resistance and stain resistance, etc., and can maintain weather resistance, transparency, stain resistance, etc. for a long time. Therefore, they are used as roof materials for membrane structures (agricultural greenhouses, sports facilities, tents, etc.), spreading films, wall decoration materials, surface laminated films for various substrates, etc. For example, Patent Document 2 proposes a fluorinated film suitable for outdoor use, especially for greenhouse films in the agricultural field, which is a single-layer polymer film containing a polyvinylidene fluoride (PVDF) matrix. In addition, Patent Document 3 proposes a multi-layer agricultural film, which is a laminated film having a three-layer structure, with the intermediate layer composed of low-density polyethylene (LLDPE) and the outer layer composed of a composition containing high-density polyethylene (HDPE) and polyvinylidene fluoride (PVDF).

[0005] However, there is still a need for these films in the prior art to improve chemical resistance and weather resistance. Therefore, there is a need to provide a film with further improved weather resistance and chemical resistance, a method for manufacturing the same, and uses thereof.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 6-166762

[0009] Patent Document 2: Chinese Patent Application No. CN105814122A

[0010] Patent Document 3: Japanese Patent Laid-Open No. 2000-324959 Summary of the Invention

[0011] Technical Problem to be Solved by the Invention

[0012] An object of the present invention is to provide a film having further improved weather resistance and chemical resistance.

[0013] Another object of the present invention is to provide a method for manufacturing the film.

[0014] Still another object of the present invention is to provide a use of the film.

[0015] Means for Solving the Technical Problem

[0016] Specific means for solving the above technical problem include the following solutions.

[0017] <1>A film comprising a non-fluororesin and a fluororesin,

[0018] wherein the content of the fluororesin is 0.1 to 20.0% by mass relative to the total mass of the non-fluororesin,

[0019] and the fluorine atom content of the fluororesin is 50% by mass or less.

[0020] <2>The film according to <1>, wherein the non-fluororesin is selected from at least one of polyolefin, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, polystyrene, polyurethane, polyester, polycarbonate, (meth)acrylic resin, and vinyl ester resin.

[0021] <3>The film according to <1>, wherein the non-fluororesin is selected from at least one of polyethylene, polyvinyl chloride, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, polystyrene, polyurethane, polyester, polycarbonate, (meth)acrylic resin, vinyl chloride resin, and vinyl ester resin.

[0022] <4>The film according to any one of <1> to <3>, wherein the fluororesin comprises a fluoropolymer containing units based on fluoroolefins, and the fluoroolefins have 2 to 8 carbon atoms.

[0023] <5>The film according to any one of <1> to <3>, wherein the fluororesin comprises a fluoropolymer containing units based on fluoroolefins, and the fluoroolefins are selected from at least one of CF2=CF2, CF2=CFCl, CF2=CHF, CH2=CF2, CF2=CFCF3, CF2=CHCF3, CF3CH=CHF, and CF3CF=CH2.

[0024] <6>The film according to any one of <1> to <3>, wherein the fluororesin comprises a fluoropolymer containing units based on fluorinated olefins and units based on non-fluorine monomers, and the fluorinated olefin is selected from at least one of CF2=CF2, CF2=CFCl, CF2=CHF, CH2=CF2, CF2=CFCF3, CF2=CHCF3, CF3CH=CHF, and CF3CF=CH2.

[0025] <7>The film according to <6>, wherein the unit based on the non-fluorine monomer comprises a unit based on a monomer having a crosslinkable group.

[0026] <8>The film according to <7>, wherein the monomer having a crosslinkable group is selected from at least one of carboxylic acids capable of polymerizing with vinyl alcohol and fluorinated olefins, vinyl ethers having a crosslinkable group other than an ethylenically unsaturated group, vinyl esters having a crosslinkable group other than an ethylenically unsaturated group, allyl ethers having a crosslinkable group other than an ethylenically unsaturated group, allyl esters having a crosslinkable group other than an ethylenically unsaturated group, acrylates having a crosslinkable group other than an ethylenically unsaturated group, and methacrylates having a crosslinkable group other than an ethylenically unsaturated group.

[0027] <9>The film according to <6>, wherein the unit based on the non-fluorine monomer contained in the fluororesin comprises a unit based on a monomer having a crosslinkable group, and the monomer having a crosslinkable group is selected from at least one of carboxylic acids capable of polymerizing with vinyl alcohol and fluorinated olefins, vinyl ethers having a crosslinkable group, vinyl esters, allyl ethers, allyl esters, acrylates, and methacrylates.

[0028] <10>The film according to any one of <7> and <9>, wherein the monomer having a crosslinkable group is selected from at least one of CH2=CHCOOH, CH(CH3)=CHCOOH, CH2=C(CH3)COOH, CH2=CH(CH2) n2 COOH, CH2=CHO-CH2-cyclo-C6H 10 -CH2OH, CH2=CHCH2O-CH2-cyclo-C6H 10 -CH2OH, CH2=CHOCH2CH2OH, CH2=CHCH2OCH2CH2OH, CH2=CHOCH2CH2CH2CH2OH, CH2=CHCH2OCH2CH2CH2CH2OH, CH2=CHCOOCH2CH2OH, and CH2=C(CH3)COOCH2CH2OH, wherein n2 represents an integer of 1 to 10.

[0029] <11>The film as described in <4> or <5>, wherein the glass transition temperature of the fluoropolymer is above 10 °C.

[0030] <12>The film as described in any one of <4>, <5> and <11>, wherein the melt viscosity of the fluoropolymer at 180 °C is 0.5 to 1000 Pa·s.

[0031] <13>The film as described in any one of <1> to <10>, which is formed by melt-kneading a raw material containing the non-fluororesin and the fluororesin.

[0032] <14>The method for manufacturing the film as described in any one of <1> to <13>, which includes melt-kneading a raw material containing the non-fluororesin and the fluororesin to form a film, wherein

[0033] the content of the fluororesin is 0.1 to 20.0% by mass relative to the total mass of the non-fluororesin,

[0034] the fluorine atom content of the fluororesin is 50% by mass or less.

[0035] <15>The use of the film as described in any one of <1> to <13> as a release film, a film for building structures, an agricultural film, a film for protecting wind power generation blades, a decorative film, a packaging film, a paint protection film for automobiles, a film for communication towers or a film for airplanes.

[0036] <16>The use of the film as described in any one of <1> to <13> as a film for a solar cell backsheet. Detailed Embodiments

[0037] Hereinafter, the embodiments of the present invention will be described in detail. However, the embodiments of the present invention are not limited to the following embodiments.

[0038] The term "process" in the present disclosure means that, in addition to a process independent of other processes, if it can achieve the purpose of the process even in a case where it cannot be clearly distinguished from other processes, it also includes that process.

[0039] The numerical range represented by "~" in the present disclosure means a range including the numerical values respectively described before and after "~" as the lower limit value and the upper limit value.

[0040] In the numerical ranges described hierarchically in the present disclosure, the upper limit value or the lower limit value described in one numerical range can also be replaced with the upper limit value or the lower limit value of other hierarchically described numerical ranges. In addition, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range can also be replaced with the value shown in the examples.

[0041] In the present disclosure, each component may contain a plurality of corresponding substances. In the case where a plurality of corresponding substances of each component are present in the composition, unless otherwise specified, the content or content ratio of each component refers to the total content or content ratio of the plurality of substances present in the composition.

[0042] In the present disclosure, the term "layer" or "film" means that when observing the region where the layer or film is present, in addition to the case where it is formed over the entire region, it also includes the case where it is formed only on a part of the region.

[0043] In the present disclosure, the term "lamination" means laminating layers, which may be the combination of two or more layers, or two or more layers may be detachable.

[0044] In the present disclosure, the "(meth)acrylic resin" means at least one of an acrylic resin and a methacrylic resin.

[0045] In the present disclosure, the following values refer to the values measured by the following methods.

[0046] The hydroxyl value and acid value are the values measured according to the method of JIS K0070-3 (1992).

[0047] The glass transition temperature Tg is the midpoint glass transition temperature of the polymer measured by differential scanning calorimetry (DSC).

[0048] The number average molecular weight Mn is the value obtained by measuring using polystyrene as a standard substance and gel permeation chromatography.

[0049] A unit is a general term for one molecule of an atomic group derived directly from a monomer by polymerization of the monomer and an atomic group obtained by chemically transforming a part of the above atomic group. The content (mol%) of each unit relative to all the units contained in the polymer can be determined by analyzing the polymer by nuclear magnetic resonance (NMR).

[0050] The fluorine atom content is the ratio (mass%) of the mass of fluorine atoms to the total mass of the fluororesin, and is measured by nuclear magnetic resonance (NMR).

[0051] The melt viscosity is the value at a specified temperature when heating from 130°C to 200°C at a rate of 10°C / minute under a frequency of 1 Hz using a rotational rheometer.

[0052] The 300 nm transmittance is the value of the light transmittance at a wavelength of 300 nm in the total light transmittance measurement according to JIS K 7361-1 (1997).

[0053] The tensile breaking strength is the tensile failure stress (MPa) measured at a test speed of 200 mm / min for a dumbbell No. 5 specimen specified in JIS K6251:2010 (ISO 37) in accordance with JIS K7127:1999.

[0054] The tensile elongation at break is the value measured in accordance with ASTM-D638.

[0055] The film of the present disclosure is a film containing a non-fluororesin and a fluororesin. The content of the fluororesin is 0.1 to 20.0% by mass relative to the total mass of the non-fluororesin, and the fluorine atom content of the fluororesin is 50% by mass or less. The inventors of the present invention have intensively studied and found that in the film of the present disclosure, by melt-kneading with a non-fluororesin and a fluororesin having a specific fluorine atom content and the proportion of the content of the fluororesin relative to the total mass of the non-fluororesin being within a specific range, the dispersibility of the fluororesin in the non-fluororesin is good. As a result, after melting, the fluororesin can uniformly diffuse in the non-fluororesin, and can also protect other components such as lubricants and light stabilizers in the film, further improving the weather resistance and chemical resistance, and enabling a film with excellent film properties to be produced. The film of the present disclosure contains a non-fluororesin and a fluororesin having a specific fluorine atom content in the same layer, and the proportion of the content of the fluororesin relative to the total mass of the non-fluororesin is within a specific range. In one embodiment of the present disclosure, the film can be obtained by melt-kneading a raw material containing the non-fluororesin and the fluororesin.

[0056] In one embodiment of the present disclosure, the raw material contains a non-fluororesin and a fluororesin. In the production of the raw material, the non-fluororesin, the fluororesin, and other components such as a plasticizer, a lubricant, and a light stabilizer used as needed are put into an extruder and melt-kneaded to produce a film.

[0057] <Non-fluororesin>

[0058] Examples of the non-fluororesin in the raw material include polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, polystyrene, polyurethane, polyester, polycarbonate, (meth)acrylic resins, vinyl ester resins, etc. Among them, from the viewpoint of the balance between weather resistance and cost, it is preferable to contain at least one selected from polyolefins and polyvinyl chloride, more preferably to contain at least one of polyethylene, polyvinyl chloride, and polypropylene, and still more preferably to contain polyethylene and polyvinyl chloride. They can be used alone or in combination of two or more.

[0059] In the non-fluororesin, the total content of at least one selected from polyolefins, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, polystyrene, polyurethanes, polyesters, polycarbonates, (meth)acrylic resins, and vinyl ester resins is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 99% by mass or more, and particularly preferably 100% by mass.

[0060] When a polyester resin is contained as the non-fluororesin, it contains a structure in which units based on a polycarboxylic acid compound ("carboxylic acid units") and units based on a polyol compound ("alcohol units") are linked by an ester bond. The polyester resin may also contain units based on hydroxycarboxylic acids and the like as units other than the carboxylic acid units and the alcohol units.

[0061] As the polyester, for example, a polymer having units based on an aromatic polycarboxylic acid compound having 8 to 15 carbon atoms and units based on a polyol compound having 2 to 10 carbon atoms can be used.

[0062] The hydroxyl value of the polyester is preferably 20 to 100 mg KOH / g, more preferably 30 to 80 mg KOH / g. The acid value of the polyester is preferably 1 to 80 mg KOH / g, more preferably 3 to 50 mg KOH / g.

[0063] From the viewpoint of melt viscosity, the number average molecular weight (Mn) of the polyester is preferably 5000 or less. In addition, the weight average molecular weight (Mw) of the polyester is preferably 6000 to 20000, more preferably 6000 to 10000.

[0064] From the viewpoint of melt viscosity, the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the polyester are preferably Mn of 5000 or less and Mw of 6000 to 20000, more preferably Mn of 5000 or less and Mw of 6000 to 10000.

[0065] Specific examples of the polyester include "CRYLCOAT (registered trademark) 4642-3" and "CRYLCOAT (registered trademark) 4890-0" manufactured by Daicel Ornex Co., Ltd., and "GV-250", "GV-740", and "GV-175" manufactured by Yupika Co., Ltd.

[0066] The (meth)acrylic resin preferably contains units based on at least one selected from acrylic acid and methacrylic acid, and units based on one or more selected from acrylic esters and methacrylic esters.

[0067] As specific examples of the acrylic resin, for example, "FINEDIC (registered trademark) A-249", "FINEDIC (registered trademark) A-251", "FINEDIC (registered trademark) A-266" manufactured by DIC Corporation, "ALMATEX (registered trademark) PD6200", "ALMATEX (registered trademark) PD7310" manufactured by Mitsui Chemicals, Inc., and "SANPEX PA-55" manufactured by Sanyo Chemical Industries, Ltd. can be exemplified.

[0068] Polyurethane is a mixture of polyols (acrylic polyol, polyester polyol, polyether polyol, propylene glycol, etc.) and an isocyanate compound, or a resin obtained by reacting the mixture, and preferably a mixture of powdered polyols (acrylic polyol, polyester polyol, polyether polyol) and powdered isocyanate.

[0069] As the non-fluororesin, it is preferably solid at room temperature (25 °C), the softening point is preferably 100 to 150 °C, the glass transition temperature Tg is preferably 30 to 60 °C, and the melting point is preferably 200 °C or lower.

[0070] <Fluororesin>

[0071] The fluororesin used in the raw materials may include a fluoropolymer containing units based on fluoroolefins. Fluoroolefins are olefins in which one or more hydrogen atoms are replaced by fluorine atoms. The number of carbon atoms of the fluoroolefin is preferably 2 to 8, more preferably 2 to 6. The number of fluorine atoms in the fluoroolefin is preferably 2 or more, more preferably 3 to 4. When the number of fluorine atoms is 2 or more, the weather resistance of the cured film is excellent. In the fluoroolefin, one or more of the hydrogen atoms not replaced by fluorine atoms may be replaced by chlorine atoms.

[0072] As specific examples of the fluoroolefin, CF2=CF2, CF2=CFCl, CF2=CHF, CH2=CF2, CF2=CFCF3, CF2=CHCF3, CF3CH=CHF, and CF3CF=CH2 can be exemplified. From the viewpoint of polymerizability, CF2=CFCl, CF3CH=CHF, or CF3CF=CH2 is preferred. The fluoroolefin may be used alone or in combination of two or more.

[0073] In the total amount of the units based on the fluoroolefin, the total content of the units based on at least one selected from CF2=CF2, CF2=CFCl, CF2=CHF, CH2=CF2, CF2=CFCF3, CF2=CHCF3, CF3CH=CHF, and CF3CF=CH2 is preferably 90 mol% or more, more preferably 95 mol% or more, still more preferably 99 mol% or more, and particularly preferably 100 mol%.

[0074] The fluoropolymer may contain only units based on fluoroolefins, may contain only units based on fluorinated monomers other than fluoroolefins, or may contain units based on fluorinated monomers other than fluoroolefins in addition to units based on fluoroolefins. Further, in addition to units based on fluorinated monomers, units based on non-fluorinated monomers may also be contained.

[0075] Examples of the fluoropolymer containing only units based on fluoroolefins include homopolymers of fluoroolefins and copolymers of two or more fluoroolefins. Specific examples include polychlorotrifluoroethylene, copolymers of tetrafluoroethylene and hexafluoropropylene, and polyvinylidene fluoride.

[0076] Examples of the fluoropolymer containing units based on fluorinated monomers other than fluoroolefins in addition to units based on fluoroolefins include fluoroolefin / perfluoro(alkyl vinyl ether) copolymers, preferably fluoroolefin / perfluoro(C 1-10 alkyl vinyl ether) copolymers, more preferably fluoroolefin / perfluoro(C 1-6 alkyl vinyl ether) copolymers. Specific examples include tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymers, preferably tetrafluoroethylene / perfluoro(C 1-10 alkyl vinyl ether) copolymers, more preferably tetrafluoroethylene / perfluoro(C 1-6 alkyl vinyl ether) copolymers.

[0077] As the fluorinated monomer, fluoroolefins are better than the above-mentioned fluorinated monomers other than fluoroolefins. As the fluoropolymer, it is better to contain only fluoroolefins as the fluorinated monomer than to contain fluoroolefins and fluorinated monomers other than fluoroolefins.

[0078] In all the units contained in the fluoropolymer, the content of the units based on fluoroolefins is preferably 5 to 100 mol%, more preferably 20 to 70 mol%, and particularly preferably 40 to 60 mol%.

[0079] When the fluoropolymer contains units based on non-fluorinated monomers, the units based on non-fluorinated monomers preferably contain units based on monomers having a crosslinkable group. The crosslinkable group described here refers to a crosslinkable group other than an ethylenically unsaturated group. By using a monomer having a crosslinkable group, the compatibility between the fluororesin and a plasticizer or the like in the film component can be improved, and components such as a plasticizer can be retained in the film, preventing embrittlement of the film over time due to the elution of these components, enabling the film to remain unbrittled even after long-term use, and maintaining excellent film properties. In this case, if a curing agent is used as a raw material, the above-mentioned crosslinkable group serves as a crosslinking point, and the crosslinking reaction of the fluoropolymer bonds proceeds through the curing agent, improving the physical properties of the cured film. Examples of the crosslinkable group include a hydroxyl group, a carboxyl group, an amino group, an alkoxysilyl group, or an epoxy group. From the viewpoints of water resistance, chemical resistance, impact resistance, etc. of the cured film, a hydroxyl group or a carboxyl group is preferred, and a hydroxyl group is more preferred.

[0080] Examples of the monomer having a crosslinkable group include carboxylic acids capable of polymerizing with vinyl alcohol and fluoroolefins, and vinyl ethers, vinyl esters, allyl ethers, allyl esters, acrylates, and methacrylates having a crosslinkable group other than an ethylenically unsaturated group.

[0081] In the total amount of units based on the monomer having a crosslinkable group, the total content of units based on at least one selected from carboxylic acids capable of polymerizing with vinyl alcohol and fluoroolefins, and vinyl ethers, vinyl esters, allyl ethers, allyl esters, acrylates, and methacrylates having a crosslinkable group other than an ethylenically unsaturated group is preferably 90 mol% or more, more preferably 95 mol% or more, still more preferably 99 mol% or more, and particularly preferably 100 mol%.

[0082] Specific examples of the monomer having a crosslinkable group include CH2=CHCOOH, CH(CH3)=CHCOOH, CH2=C(CH3)COOH, and a compound represented by the formula CH2=CH(CH2) n2 COOH (wherein n2 represents an integer of 1 to 10), CH2=CHO-CH2-cyclo-C6H 10 -CH2OH, CH2=CHCH2O-CH2-cyclo-C6H 10 -CH2OH, CH2=CHOCH2CH2OH, CH2=CHCH2OCH2CH2OH, CH2=CHOCH2CH2CH2CH2OH, CH2=CHCH2OCH2CH2CH2CH2OH, CH2=CHCOOCH2CH2OH, and

[0083] CH2=C(CH3)COOCH2CH2OH. In addition, "-cyclo-C6H 10 -" represents cyclohexylene, and the bonding position of "-cyclo-C6H 10 -" is usually 1,4-. The monomer having a crosslinkable group may be used alone or in combination of two or more.

[0084] In the total amount of units based on the monomer having a crosslinkable group, based on CH2=CHCOOH, CH(CH3)=CHCOOH, CH2=C(CH3)COOH, and the compound represented by the formula CH2=CH(CH2) n2 COOH (wherein n2 represents an integer of 1 to 10), CH2=CHO-CH2-cyclo-C6H 10 -CH2OH, CH2=CHCH2O-CH2-cyclo-C6H 10The total content of units of at least one of -CH2OH, CH2=CHOCH2CH2OH, CH2=CHCH2OCH2CH2OH, CH2=CHOCH2CH2CH2CH2OH, CH2=CHCH2OCH2CH2CH2CH2OH, CH2=CHCOOCH2CH2OH, and CH2=C(CH3)COOCH2CH2OH is preferably 90 mol% or more, more preferably 95 mol% or more, still more preferably 99 mol% or more, and particularly preferably 100 mol%.

[0085] From the perspective of excellent physical properties of the cured film, among all the units contained in the fluoropolymer, the content of units based on monomers having a crosslinkable group can be 0.5 to 100 mol%, preferably 10 to 60 mol%, more preferably 10 to 55 mol%, still more preferably 15 to 50 mol%, or can be 0.5 to 35 mol%, preferably 3 to 30 mol%, more preferably 5 to 25 mol%, and particularly preferably 5 to 20 mol%.

[0086] The fluoropolymer may also contain units based on monomers that do not contain fluorine atoms and do not have a crosslinkable group. Examples of the above units include olefins, vinyl ethers, vinyl esters, allyl ethers, allyl esters, acrylates, methacrylates, etc., preferably vinyl ethers, vinyl esters, allyl ethers, allyl esters, acrylates or methacrylates, and more preferably vinyl ethers or vinyl esters. As specific examples, ethylene, propylene, ethyl vinyl ether, 2-ethylhexyl vinyl ether, vinyl acetate, vinyl benzoate, methyl acrylate, methyl methacrylate, butyl acrylate, and butyl methacrylate can be exemplified.

[0087] Among them, from the perspective of the glass transition temperature of the fluoropolymer, the fluoropolymer preferably contains units based on monomers having a tertiary carbon-containing alkyl group with 3 to 9 carbon atoms or a cycloalkyl group with 4 to 10 carbon atoms in the side chain. However, this unit does not contain fluorine atoms and crosslinkable groups.

[0088] Examples of the tertiary carbon-containing alkyl group with 3 to 9 carbon atoms or the cycloalkyl group with 4 to 10 carbon atoms include tert-butyl, neodecyl, cyclohexyl, cyclohexylmethyl, 4-cyclohexylcyclohexyl, 1-decahydronaphthyl, etc.

[0089] As specific examples of the above units, cyclohexyl vinyl ether, tert-butyl vinyl ether, vinyl pivalate, vinyl tert-butylbenzoate, and vinyl neodecanoate can be exemplified. The above units can be used alone or in combination of two or more.

[0090] From the viewpoints of the glass transition temperature of the fluoropolymer and the flexibility of the cured film, among all the units contained in the fluoropolymer, the content of the units based on monomers that do not contain fluorine atoms and do not have crosslinkable groups is preferably 5 to 60 mol%, more preferably 10 to 50 mol%.

[0091] In the total amount of the fluoropolymer, the total amount of the units based on fluoroolefins, the units based on monomers having crosslinkable groups, and the units based on monomers that do not contain fluorine atoms and do not have crosslinkable groups is preferably 90 mol% or more, more preferably 95 mol% or more, further preferably 99 mol% or more, and particularly preferably 100 mol%.

[0092] Relative to all the units of the fluoropolymer, the contents of the units based on fluoroolefins, the units based on monomers having crosslinkable groups, and the units based on monomers that do not contain fluorine atoms and do not have crosslinkable groups in the fluoropolymer are preferably 20 to 70 mol%, 10 to 60 mol%, and 20 to 70 mol% in this order.

[0093] The fluoropolymer preferably contains units based on vinyl ethers. Relative to all the units of the fluoropolymer, the content of the units based on vinyl ethers is preferably 5 mol% or more, more preferably 15 mol% or more, further preferably 20 mol% or more, and particularly preferably 30 mol% or more. In addition, the content of the units based on vinyl ethers relative to all the units of the fluoropolymer is preferably 80.0 mol% or less, more preferably 70.0 mol% or less, and further preferably 60.0 mol% or less.

[0094] From the viewpoints of the water resistance and smoothness of the cured film, the Mn of the fluoropolymer is preferably 3000 to 50000, more preferably 5000 to 30000.

[0095] When the fluororesin contains a fluoropolymer having a hydroxyl group, the hydroxyl value of the fluoropolymer is preferably 5 to 200 mg KOH / g, more preferably 10 to 150 mg KOH / g.

[0096] When the fluororesin contains a fluoropolymer having a carboxyl group, the acid value of the fluoropolymer is preferably 1 to 150 mg KOH / g, more preferably 3 to 100 mg KOH / g, and particularly preferably 5 to 50 mg KOH / g.

[0097] The fluoropolymer may have only either an acid value or a hydroxyl value, or may have both. When the fluoropolymer has both an acid value and a hydroxyl value, the total of the acid value and the hydroxyl value is preferably 1 to 80 mg KOH / g. If the total of the acid value and the hydroxyl value is within the above range, the glass transition temperature of the fluoropolymer can be appropriately adjusted, and the physical properties of the cured film are excellent.

[0098] In one embodiment of the present disclosure, the fluororesin is a crosslinked product of a fluoropolymer containing a crosslinkable group and a curing agent.

[0099] The glass transition temperature of the fluoropolymer is preferably 10 °C or higher, more preferably 30 to 150 °C, still more preferably 40 to 120 °C, and further preferably 50 to 100 °C.

[0100] The melt viscosity of the fluoropolymer at 180 °C is preferably 0.5 to 1000 Pa·s, more preferably 0.6 to 900 Pa·s, and further preferably 0.7 to 800 Pa·s.

[0101] The melting point of the fluororesin is preferably 300 °C or lower, more preferably 200 °C or lower, and particularly preferably 180 °C or lower. From the viewpoints of anti-caking property and smoothness of the cured film, the glass transition temperature of the fluororesin is preferably 30 to 150 °C, more preferably 40 to 120 °C, and further preferably 50 to 100 °C.

[0102] From the viewpoint of uniform mixing with non-fluororesin, the melt viscosity of the fluororesin at 150 to 200 °C is preferably 1000 Pa·s or lower, more preferably 700 Pa·s or lower, and further preferably 500 Pa·s or lower.

[0103] In the present disclosure, the fluorine atom content of the fluororesin is 50% by mass or less. In one embodiment of the present disclosure, the fluorine atom content of the fluororesin is 10 to 50% by mass, preferably 15 to 40% by mass, and more preferably 20 to 30% by mass. By making the fluorine atom content of the fluororesin within this range, the fluororesin has good dispersibility in the non-fluororesin, can be uniformly diffused in the non-fluororesin after melting, can also protect other components such as lubricants and light stabilizers in the film, further improve weather resistance and chemical resistance, and obtain excellent film properties.

[0104] In one embodiment of the present disclosure, the content of the fluororesin is 0.1 to 20.0% by mass, preferably 0.5 to 15.0% by mass, more preferably 1.0 to 10.0% by mass, and further preferably 1.0 to 9.0% by mass based on the total mass of the non-fluororesin. By making the relative content of the fluororesin within this range, the fluororesin has good dispersibility in the non-fluororesin, can be uniformly diffused in the non-fluororesin after melting, does not cause the film to become brittle, can also protect other components such as lubricants and light stabilizers in the film, further improve weather resistance and chemical resistance, and obtain excellent film properties.

[0105] In one embodiment of the present disclosure, the fluororesin is obtained by introducing an organic solvent, a fluoroolefin monomer, an optional monomer having a crosslinkable group, a monomer containing no fluorine atom and no crosslinkable group, and a polymerization initiator into an autoclave, and raising the temperature to carry out a polymerization reaction to obtain a powdery fluororesin.

[0106] In one embodiment of the present disclosure, a film is formed by melt-kneading a raw material containing the non-fluororesin and the fluororesin. Among them, the total mass of the fluororesin and the non-fluororesin relative to the total mass of the raw material may be 50 to 100% by mass, may be 60 to 99.5% by mass, or may be 80 to 99% by mass.

[0107] <Curing agent>

[0108] In one embodiment of the present disclosure, the raw material may contain a curing agent in addition to the fluororesin and the non-fluororesin. However, the curing agent may not be added at the stage of the raw material, but may be added after the fluororesin and the non-fluororesin are kneaded and pulverized. In addition, when the fluororesin and the non-fluororesin can be cured by other methods without using a curing agent, the curing agent may not be added.

[0109] As the curing agent, known compounds can be used, and examples include isocyanate curing agents, melamine resins, guanamine resins, sulfonamide resins, urea resins, amine curing agents such as aniline resins, β-hydroxyalkylamide curing agents, and isocyanuric acid triglycidyl ester curing agents. The curing agent can be used alone or in combination of two or more.

[0110] The curing agent is preferably an isocyanate curing agent, and its glass transition temperature is 30 to 100 °C, and the content of the isocyanate group relative to the total mass of the curing agent can be 0.1 to 30.0% by mass.

[0111] The softening temperature of the curing agent is preferably 10 to 120 °C, more preferably 40 to 100 °C. When the softening temperature is 10 °C or higher, it is possible to prevent the raw material from curing at room temperature (25 °C) to form granular lumps. In addition, when it is 120 °C or lower, the curing agent can be uniformly dispersed in the raw material during the kneading process, and the smoothness and strength of the obtained cured film can be improved.

[0112] The content of the curing agent relative to 100% by mass of the raw material is preferably 1 to 50% by mass, and preferably 3 to 30% by mass.

[0113] <Other components>

[0114] In addition to the fluororesin, non-fluororesin, and curing agent, the raw material may optionally contain other components. Examples of other components include plasticizers, lubricants, light stabilizers, pigments, curing catalysts, degassing agents, surface modifiers, ultraviolet absorbers, matting agents such as ultrafine powder synthetic silica, nonionic, cationic or anionic surfactants, homogenizers, fillers, heat stabilizers, tackifiers, dispersants, antistatic agents, rust inhibitors, silane coupling agents, antifouling agents, low pollution treatment agents, etc.

[0115] As a plasticizer, at least one selected from aliphatic dibasic acid esters, benzenepolycarboxylic acid esters such as phthalic acid esters, benzoic acid esters, polyhydric alcohol esters, chlorinated hydrocarbons, epoxies, citric acid esters, polyesters, etc. can be used.

[0116] Phthalic acid ester plasticizers are preferably used. As phthalic acid ester plasticizers, phthalic acid esters such as phthalic acid esters and terephthalic acid esters can be exemplified. Phthalic acid esters are preferably used. As examples of phthalic acid esters, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, di-n-octyl phthalate, butyl benzyl phthalate, bis(2-ethylhexyl) phthalate, dioctyl phthalate, diisononyl phthalate, etc. can be exemplified.

[0117] In one embodiment of the present disclosure, the content of the plasticizer in the raw material can be 10 to 50% by mass, preferably 12 to 40% by mass, and more preferably 15 to 30% by mass.

[0118] As a lubricant, silica, fatty acid amide, oleic acid, polyester, synthetic ester, carboxylic acid, etc. can be selected. The lubricant can be used alone in one kind, or two or more kinds can be used in combination. Silica-based lubricants are preferably used, for example, SUNSPHERE H-31 (manufactured by AGC Sitech Co., Ltd. (AGC Esu Aitekku Co., Ltd.)).

[0119] In one embodiment of the present disclosure, the content of the lubricant in the raw material can be 0.1 to 20% by mass, preferably 0.2 to 10% by mass, and more preferably 0.5 to 1% by mass.

[0120] As a light stabilizer, ultraviolet absorbers such as benzotriazoles, benzophenones, salicylates, etc. or radical scavengers such as hindered amines can be used, for example, Chimassorb 944 (manufactured by BASF Japan Ltd.). The light stabilizer can be used alone in one kind, or two or more kinds can be used in combination.

[0121] In one embodiment of the present disclosure, the content of the light stabilizer in the raw material can be 0.1 to 20% by mass, preferably 0.2 to 10% by mass, and more preferably 0.5 to 1% by mass.

[0122] As the pigment, it preferably contains at least one selected from bright pigments, rust-preventive pigments, coloring pigments, and filler pigments. As bright pigments, examples include aluminum powder, nickel powder, stainless steel powder, copper powder, bronze powder, gold powder, silver powder, mica powder, graphite powder, glass flakes, flaky iron oxide powder, etc. As rust-preventive pigments, lead-free rust-preventive pigments with a small environmental load are preferred, and examples include zinc cyanamide, zinc oxide, zinc phosphate, calcium magnesium phosphate, zinc molybdate, barium borate, and zinc calcium cyanamide. The coloring pigment is a pigment that colors the cured film. As coloring pigments, examples include titanium oxide, carbon black, iron oxide, phthalocyanine blue, phthalocyanine green, quinacridone, isoindolinone, benzimidazolone, dioxazine, etc. As filler pigments, examples include talc, barium sulfate, mica, calcium carbonate, etc.

[0123] In one embodiment of the present disclosure, the content of the pigment in the raw material is preferably 20 to 200% by mass, more preferably 50 to 150% by mass, based on 100% by mass of the fluororesin.

[0124] The curing catalyst can be, for example, a tin catalyst such as tin octoate, tributyltin dilaurate, or dibutyltin dilaurate. The curing catalyst can be used alone or in combination of two or more. The content of the curing catalyst is preferably 0.0001 to 10.0 parts by mass based on 100 parts by mass of the total amount of the solid components other than the pigment.

[0125] [Method for manufacturing a film]

[0126] The method for manufacturing the film of the present disclosure includes melting and kneading a raw material containing the non-fluororesin and the fluororesin to form a film.

[0127] In one embodiment of the present disclosure, the raw material contains the non-fluororesin and the fluororesin. In the manufacture of the raw material, the fluororesin, non-fluororesin, and other components such as plasticizers, lubricants, and light stabilizers used as needed are put into an extruder for melting and kneading to form a film.

[0128] Kneading can use ordinary kneading techniques. For example, mixers, kneaders, extruders, and other various known blending and mixing equipment can be used for kneading. In one embodiment of the present disclosure, an inflatable co-extruder equipped with an extruder is used to melt and knead the raw material components.

[0129] The kneading temperature in the kneading process is preferably not less than the higher one of the glass transition temperatures of the fluororesin and non-fluororesin contained in the raw material. In addition, the kneading temperature in the kneading process is preferably not more than the curing start temperature of the raw material. Here, the curing start temperature of the raw material refers to the lower one of the curing start temperatures of the fluororesin and non-fluororesin. In addition, when the raw material contains a curing agent, it refers to the lower one of the curing start temperatures of the blend of the fluororesin and the curing agent and the blend of the non-fluororesin and the curing agent. By setting the kneading temperature to the above temperature, the resins can be uniformly mixed with each other, and the curing of the raw material in the kneading extruder can be prevented, which may otherwise impede the kneading. From the perspective of being able to control the viscosity increase of the raw material during melt-kneading and uniformly mix it, the kneading temperature can be 100°C or higher, preferably 110°C or higher. In addition, from the perspective of uniformly mixing the raw material during melt-kneading and preventing the raw material from curing in the kneading extruder and impeding the kneading, the temperature can be 300°C or lower, preferably 190°C or lower.

[0130] The film-forming method can be a known method, for example, melt extrusion method, solution casting method, calendering method, etc.

[0131] The thickness of the formed film is 0.03 to 0.2 mm, preferably 0.05 to 0.15 mm, and more preferably 0.08 to 0.12 mm. When it is 0.03 mm or more, the strength is sufficient, and when it is 0.2 mm or less, the workability of film formation and subsequent processing (cutting the film, joining it in the form of a greenhouse, spreading it on the greenhouse, etc.) is excellent.

[0132] The content of the fluororesin relative to the total mass of the non-fluororesin in the film is measured by a melt decomposition method or a perfluorine quantification method. Examples of the melt decomposition method include (1) potassium carbonate decomposition method, (2) combustion-hydrolysis method, (3) oxygen flask combustion method, and (4) sodium metal. Examples of the perfluorine quantification method include (5) fluoride ion selective electrode method, (6) ion chromatography method, (7) spectrophotometry (lanthanum-alizarin complexone method), (8) titration method, and (9) zero potential difference method.

[0133] The 300-nm transmittance of the film of the present disclosure is preferably 85.0% or more, more preferably 87.0% or more, and further preferably 90.0% or more in the initial state. In addition, the 300-nm transmittance after 500 hours of super UV (hereinafter also referred to as "SUV") irradiation is preferably 70.0% or more, more preferably 80.0% or more, and further preferably 90.0% or more. In addition, the retention rate of the 300-nm transmittance before and after 500 hours of SUV irradiation is preferably 70.0% or more, more preferably 80.0% or more, and further preferably 90.0% or more.

[0134] Compared with a film containing only non-fluorine resin, the film of the present disclosure has a high transmittance at 300 nm and a high retention rate of transmittance after SUV irradiation, and excellent weather resistance.

[0135] The tensile fracture strength of the film of the present disclosure at 25°C is preferably 10 MPa or more, more preferably 15 MPa or more, and further preferably 20 MPa or more. There is no particular limitation on the upper limit, but it is actually about 80 MPa or less.

[0136] In addition, the tensile fracture strength at 25°C after 500 hours of SUV irradiation is preferably 10 MPa or more, more preferably 15 MPa or more, and further preferably 20 MPa or more. There is no particular limitation on the upper limit, but it is actually about 80 MPa or less.

[0137] In addition, the retention rate of the tensile fracture strength before and after 500 hours of SUV irradiation is preferably 40% or more, more preferably 50% or more, and further preferably 60% or more.

[0138] The film elongation at break of the film of the present disclosure at 25°C is preferably 500% or more, more preferably 600% or more, and still more preferably 700% or more. There is no particular limitation on the upper limit, but it is actually about 1500% or less.

[0139] In addition, the elongation at break at 25°C after 500 hours of SUV irradiation is preferably 500% or more, more preferably 600% or more, and still more preferably 700% or more. There is no particular limitation on the upper limit, but it is actually about 1500% or less.

[0140] In addition, the retention rate of the elongation at break before and after 500 hours of SUV irradiation is preferably 40% or more, more preferably 50% or more, and further preferably 60% or more.

[0141] Compared with a film containing only non-fluorine resin, the film of the present invention has a high retention rate of tensile fracture strength and elongation at break after SUV irradiation, and excellent mechanical properties.

[0142] The water vapor permeability of the film of the present invention is 1.0 g / m 2 ·day (converted based on a film thickness of 25 μm) or more, preferably 3.0 g / m 2 ·day (converted based on a film thickness of 25 μm) or more, more preferably 5.0 g / m 2 ·day (converted based on a film thickness of 25 μm) or more. There is no particular limitation on the upper limit of the water vapor permeability, but it is preferably 50.0 g / m 2 ·day (converted based on a film thickness of 25 μm) or less, more preferably 40.0 g / m 2 ·day (converted based on a film thickness of 25 μm) or less, further preferably 30.0 g / m 2 ·day (converted based on a film thickness of 25 μm) or less.

[0143] The film of the present invention is superior in moisture permeability compared to a film composed only of a non-fluorine resin.

[0144] The moisture permeability of the film of the present invention is measured by the amount of water vapor passing through the test piece per 1 m per day. 2 The test piece was prepared as follows.

[0145] The moisture permeability is measured by measuring the mass (g) of water vapor passing through the test piece within 24 hours (1 day) in an atmosphere of 40°C, with the relative humidity of the space on one side separated by the test piece at 90% and the space on the other side kept dry by a moisture absorbent. 2 The test material is converted. The measurement is carried out in accordance with JIS Z 0208:1976 Moisture permeability test method for moisture-proof packaging materials (cup method). A circular test piece with a diameter of about 10 mm larger than the inner diameter of the cup is placed on a cup to which about 50 g of calcium chloride moisture absorbent has been added. A rubber gasket and a pressure ring are installed and tightened with screws so that the test piece does not shift. After measuring the total mass of the test piece, it is placed in a constant temperature and humidity chamber at 40°C and 90% RH, and the mass change at regular intervals is measured. The moisture permeability is calculated according to the following formula.

[0146] Moisture permeability (g / m 2 ·day)=W×240000 / S

[0147] Where S represents the moisture permeability area (cm 2 ), W represents the mass increase per hour (g / hr).

[0148] The film obtained in the present disclosure may be a single-layer film or a multilayer film formed by laminating a non-fluorine resin film such as a polyolefin film such as polyethylene and polypropylene with a fluorine resin such as polyvinyl fluoride and polyvinylidene fluoride. In the case of a multilayer film, a multilayer film of 2 to 10 layers is preferred, and a multilayer film of 2 to 5 layers is more preferred.

[0149] The film disclosed in the present invention has the following technical effects: excellent weather resistance, greatly extending the service life; excellent chemical resistance, even after being subjected to acid rain or pesticide spraying, it maintains good chemical resistance; it is not easy to adhere to the soil, so that the weight of the film is light when it is reused or discarded; it has high light transmittance, which is particularly useful for plant cultivation and growth; it can prevent the film from becoming brittle, avoid the dissolution of other components such as plasticizers in the film components, and it is not easy to become brittle even after long-term use.

[0150] Therefore, the film of the present invention can be widely used as a release film, a film for building structures, an agricultural film, a wind power blade protection film, a decorative film, a packaging film, a paint protection film for automobiles, a film for communication towers, a film for aircraft, or a film for solar cell backplanes.

[0151] The disclosure of Chinese Patent Application No. 202010766854.6 is incorporated herein by reference in its entirety.

[0152] All the documents, patent applications and technical standards described in this specification are incorporated into this specification to the same extent as each individual document, patent application and technical standard specifically and separately described as incorporated by reference.

[0153] Examples

[0154] The present invention will be described in more detail below through examples and comparative examples. However, the present invention is not limited to these examples. Among them, Examples 1 to 3, 5, 6, 9, and 10 are examples, Comparative Examples 4, 7, 8, and 11 are comparative examples, and Example 12 is a reference example.

[0155] <Production Example>

[0156] [Production Example 1 (Production of Fluororesin F1)]

[0157] Xylene (503 g), ethanol (142 g), CTFE (387 g), CHVE (326 g), HBVE (84.9 g), potassium carbonate (12.3 g), and a 50 mass% xylene solution of tert-butyl perneodecanoate (20 mL) were introduced into an autoclave and heated, and polymerization was carried out at 65 °C for 11 hours. Then, the solution in the autoclave was filtered to obtain a solution containing fluororesin F1 composed of a fluoropolymer. The solvent in the obtained solution was removed by vacuum drying at 65 °C for 24 hours, and further vacuum dried at 130 °C for 20 minutes. The obtained block-shaped fluororesin F1 was pulverized to obtain powdery fluororesin F1.

[0158] Fluororesin F1 is a polymer containing 50 mol% of CTFE-based units, 39 mol% of CHVE-based units, and 11 mol% of HBVE-based units in this order relative to all the units contained in fluororesin F1 (hydroxyl value: 50 mg KOH / g, glass transition temperature Tg: 52 °C, number average molecular weight Mn: 10,000, fluorine atom content: 24 mass%, content of vinyl ether-based units: 50 mol%). The melt viscosity of fluororesin F1 at 180 °C is 30 Pa·s.

[0159] [Production Example 2 (Production of Fluororesin F2)]

[0160] Xylene (56 g), ethanol (15.8 g), CTFE (63.2 g), t-BuVE (3.1 g), EVE (4.5 g), HBVE (12.1 g), PV (41.5 g), potassium carbonate (1.1 g), and a 50 mass% xylene solution of tert-butyl perpivalate (0.7 g) were introduced into an autoclave and the temperature was raised. Polymerization was carried out at 55°C for 20 hours. The temperature was further raised to 65°C and maintained for 5 hours, followed by cooling. The solution in the autoclave was filtered to obtain a solution containing fluororesin F2 composed of a fluoropolymer. The solvent in the obtained solution was removed by vacuum drying at 65°C for 24 hours, and further vacuum dried at 130°C for 20 minutes. The obtained block-shaped fluororesin F2 was pulverized to obtain powdered fluororesin F2.

[0161] Fluororesin F2 is a polymer containing 50 mol% of CTFE-based units, 3 mol% of t-BuVE-based units, 10 mol% of HBVE-based units, 6 mol% of EVE-based units, and 31 mol% of PV-based units in this order with respect to all the units contained in fluororesin F2 (hydroxyl value: 51 mg KOH / g, glass transition temperature Tg: 52°C, number average molecular weight Mn: 12,000, fluorine atom content: 24 mass%, content of vinyl ether-based units: 19 mol%). The melt viscosity of fluororesin F2 at 180°C is 5 Pa·s.

[0162] [Abbreviations in the production example]

[0163] CTFE: Chlorotrifluoroethylene

[0164] CHVE: Cyclohexyl vinyl ether

[0165] HBVE: 4-Hydroxybutyl vinyl ether

[0166] t-BuVE: tert-Butyl vinyl ether

[0167] EVE: Ethyl vinyl ether

[0168] PV: Vinyl pivalate

[0169] [Measurement method]

[0170] The hydroxyl value and acid value were measured according to the method of JIS K0070-3 (1992).

[0171] The glass transition temperature Tg was measured by differential scanning calorimetry (DSC) method to obtain the midpoint glass transition temperature of the polymer.

[0172] The number average molecular weight Mn was determined by gel permeation chromatography using polystyrene as a standard substance.

[0173] Fluorine atom content: The fluorine atom content is the ratio (mass %) of the mass of fluorine atoms to the total mass of the fluororesin, and is measured by nuclear magnetic resonance (NMR) method.

[0174] The melt viscosity is the value at a specified temperature obtained by using a rotational rheometer and raising the temperature from 130 °C to 200 °C at a rate of 10 °C per minute under the condition of a frequency of 1 Hz.

[0175] The content (mol %) of each unit relative to all the units contained in the polymer is determined by analyzing the polymer by nuclear magnetic resonance (NMR) method.

[0176] <Examples 1 to 11>

[0177] [Manufacture of film]

[0178] Using an inflation coextruder equipped with an extruder, the respective components described in the "Film composition" column shown in Table 1 below are melt-kneaded to form a film with a thickness of 0.1 mm. The obtained film is cut into a size of 1.0 m × 1.0 m for the chemical resistance evaluation described later. It is also cut into a size of 7 cm × 15 cm for use in the accelerated aging test described later.

[0179] <Example 12>

[0180] A fluorine-based coating with a dry film thickness of 10 μm is applied to a commercially available agricultural polyethylene film and then dried and cured to form a fluorine-containing coating film for the evaluation described later. The results are shown in Table 1 below.

[0181] Table 1

[0182]

[0183] [Detailed description of each component in Table 1]

[0184] · Non-fluororesin:

[0185] Polyethylene: HI-ZEX (registered trademark) 7200F (trade name, manufactured by Prime Polymer Co., Ltd.)

[0186] Polyvinyl chloride: NOVATECH EVA LV430 (trade name, manufactured by Mitsubishi Chemical Corporation)

[0187] · Fluororesin:

[0188] F1: Fluororesin F1 manufactured in Production Example 1

[0189] F2: Fluororesin F2 manufactured in Production Example 2

[0190] F3: Richflon SRF-750P (trade name, fluorinated olefin-vinyl ester fluororesin, manufactured by Beijing Sino-rich Materials Technology Co., Ltd., hydroxyl value: 54 mg KOH / g, glass transition temperature Tg: 41 °C, number average molecular weight Mn: 10,000, fluorine atom content: 22%, content of units based on vinyl ether: 0 mol%). The melt viscosity of fluororesin F3 at 180 °C is 25 Pa·s.

[0191] F4: DS203 (trade name, polyvinylidene fluoride, manufactured by Shandong Huaxia Shenzhou New Materials Co., Ltd., melting point: 179 °C, fluorine atom content: 59%, content of units based on vinyl ether: 0 mol%). The melt viscosity of fluororesin F4 at 180 °C is 2000 Pa·s.

[0192] · Plasticizer: Di-n-octyl phthalate

[0193] · Silica lubricant: SUNSPHERE H-31 (manufactured by AGC Sitech Co., Ltd.)

[0194] · Light stabilizer: Chimassorb 944 (manufactured by BASF Japan Co., Ltd.)

[0195] [Evaluation method]

[0196] (Chemical resistance)

[0197] The film was immersed in acidic water for 8 hours, then covered on a round tank filled with 60 °C hot water and left standing for 50 days, and the appearance change of the film was visually observed. Evaluation was carried out according to the following criteria.

[0198] A: The appearance of the film has no change

[0199] B: The appearance of the film is soiled

[0200] C: The appearance of the film is damaged

[0201] (Weather resistance)

[0202] An accelerated weathering test was carried out using an accelerated weathering tester (manufactured by Q-Panel Lab Products Corp, model: QUV / SE) with a test time of 1000 hours. The appearance of the film after the test was visually confirmed and evaluated according to the following criteria.

[0203] A: The appearance of the film has no change

[0204] B: The appearance of the film is soiled

[0205] C: The appearance of the film is damaged

[0206] (Optical property evaluation)

[0207] After irradiating the film with a super UV test machine (manufactured by Iwasaki Electric Co., Ltd., super accelerated weathering test machine) for 500 hours, measure the transmittance (%) at a wavelength of 300 nm. Calculate the retention rate (%) of the light transmittance based on the light transmittance before and after the test. It can be said that the higher the retention rate, the better the weather resistance of the film. The evaluation is carried out according to the following criteria.

[0208] A: The retention rate of the light transmittance is 90% or more

[0209] B: The retention rate of the light transmittance is 70% or more and less than 90%

[0210] C: The retention rate of the light transmittance is 50% or more and less than 70%

[0211] D: The retention rate of the light transmittance is less than 50%

[0212] (Mechanical strength (1))

[0213] After irradiating the film with a super UV test machine (manufactured by Iwasaki Electric Co., Ltd., super accelerated weathering test machine) for 500 hours, measure the tensile fracture strength (tensile stress at the time of specimen fracture) through a tensile test. Calculate the retention rate (%) of the tensile fracture strength before and after the test. It can be said that the higher the retention rate, the better the weather resistance of the film. The evaluation is carried out according to the following criteria.

[0214] A: The retention rate of the tensile fracture strength is 60% or more

[0215] B: The retention rate of the tensile fracture strength is 40% or more and less than 60%

[0216] C: The retention rate of the tensile fracture strength is 20% or more and less than 40%

[0217] D: The retention rate of the tensile fracture strength is less than 20%

[0218] (Mechanical strength (2))

[0219] After irradiating the film with a super UV test machine (manufactured by Iwasaki Electric Co., Ltd., super accelerated weathering test machine) for 500 hours, measure the tensile fracture elongation through a tensile test. Calculate the retention rate (%) of the tensile fracture elongation before and after the test. It can be said that the higher the retention rate, the better the weather resistance of the film. The evaluation is carried out according to the following criteria.

[0220] A: The retention rate of the tensile fracture elongation is 60% or more

[0221] B: The retention rate of the tensile fracture elongation is 40% or more and less than 60%

[0222] C: The retention rate of the elongation at break is 20% or more and less than 40%.

[0223] D: The retention rate of the elongation at break is less than 20%.

[0224] (Water vapor permeability)

[0225] The water vapor permeability (g / m 2 ·day (converted to a film thickness of 25 μm)) of the films obtained in the examples and comparative examples was measured according to the water vapor permeability test method (cup method) of JIS Z0208:1976 for moisture-proof packaging materials.

[0226] From the results in Table 1, it can be seen that the films of Examples 1 to 3, 5, 6, 9, and 10 have excellent chemical resistance and weather resistance, and also excellent retention rates of light transmittance, tensile breaking strength, and then the retention rate of elongation at break. Among them, in Examples 1, 3, 9, and 10, the fluororesin can be uniformly diffused in the non-fluororesin after melting, and can also protect other components such as light stabilizers in the film, obtaining a film with excellent film properties and extremely excellent chemical resistance and weather resistance.

[0227] In contrast, in Example 4 as a comparative example, the content of the fluororesin relative to the total mass of the non-fluororesin was set too high, the film became brittle, and both the chemical resistance and weather resistance were poor.

[0228] In Example 7 as a comparative example, a fluororesin with too high a fluorine atom content was used, the dispersibility of the fluororesin decreased, and both the chemical resistance and weather resistance were poor.

[0229] In Example 8 as a comparative example, no fluororesin was used, so the film properties were low, and both the chemical resistance and weather resistance were poor.

[0230] In Example 11 as a comparative example, a fluororesin with too high a fluorine atom content was used, the plasticizer leached out, the film properties were low, and both the chemical resistance and weather resistance were poor.

[0231] Examples 4, 7, 8, and 11 as comparative examples are also poor in terms of the retention rate of light transmittance, the retention rate of tensile breaking strength, and the retention rate of elongation at break.

[0232] In Example 12 as a reference example, a laminate of a fluororesin coating film and a non-fluororesin coating film was formed by coating a fluorine-based coating on a commercially available agricultural polyethylene film. As a result, deterioration started from the interface between the fluororesin coating film and the non-fluororesin coating film, and peeling of the fluororesin coating film occurred. It can be seen that compared with the coating film formed by applying a fluorine-based coating on a non-fluororesin film, the film of the present disclosure has no risk of coating film peeling and significantly has more excellent chemical resistance and weather resistance. Example 12 is also poor in terms of the retention rate of tensile breaking strength and the retention rate of elongation at break.

[0233] <Manufacturing of Solar Cell Backsheet Film>

[0234] 4 kg of polymethylpentene as a non-fluorine resin, 0.5 kg of polyethylene glycol as a dispersing aid, 1 kg of a copolymer of polybutylene terephthalate and polytetramethylene glycol, 3 kg of fluororesin (F1), and 2 kg of titanium oxide were mixed into 90 kg of polyethylene terephthalate, fully mixed and dried, and supplied to an extruder heated to 270 to 300° C. The mixture was extruded from a T-die of the extruder to form a film (thickness: 50 μm).

[0235] <Manufacturing of Solar Cell Back Sheet>

[0236] A fluorine coating (AGC Coating Technology Co., Ltd., product name "Obbligatto") was applied to one side of the obtained film with a polyester adhesive to a film thickness of 20 μm, and dried at 80°C for 1 hour. A 100 μm EVA (ethylene-vinyl acetate copolymer) sheet was superimposed on the surface of the obtained film opposite to the coated surface with a polyester adhesive, and the film was dried at 150°C at a pressure of 100 g / cm 2 Load crimping to make solar cell back panels.

[0237] <Manufacturing of solar cell modules>

[0238] On the EVA sheet side of the obtained solar cell back sheet, the solar cell unit, the EVA sheet and the glass sheet are stacked in order from the near side to the far side of the EVA sheet to produce a solar cell module.

[0239] Industrial Applicability

[0240] The film disclosed in the present invention has excellent weather resistance and greatly extends its service life; it has excellent chemical resistance and maintains good chemical resistance even after being subjected to acid rain or pesticide spraying; it is not easy to adhere to the soil, so that the weight of the film is light when it is reused or discarded; it has high light transmittance and is particularly useful for plant cultivation and growth; it can prevent the film from becoming brittle and avoid the dissolution of other components such as plasticizers in the film components, and it is not easy to become brittle even after long-term use. Therefore, the film disclosed in the present invention can be widely used as a demoulding film, a film for building structures, an agricultural film, a wind power blade protection film, a decorative film, a packaging film, a paint protection film for automobiles, a film for communication towers or aircraft, a film for solar cell back panels, and the like.

Claims

1. A film which is a film containing a non-fluororesin and a fluororesin, wherein the fluororesin contains a fluoropolymer containing units based on a fluoroolefin and units based on a non-fluoromonomer, the fluoroolefin has 2 to 8 carbon atoms, the units based on the non-fluoromonomer contain units based on a monomer having a crosslinkable group, the content of the fluororesin is 4.0 to 10.0% by mass relative to the total mass of the non-fluororesin, the fluorine atom content of the fluororesin is 50% by mass or less, the non-fluororesin is selected from at least one of polyethylene and polyvinyl chloride.

2. The membrane according to claim 1, wherein The fluororesin contains a fluoropolymer containing units based on a fluoroolefin and units based on a non-fluoromonomer, and the fluoroolefin is selected from at least one of CF2=CF2, CF2=CFCl, CF2=CHF, CH2=CF2, CF2=CFCF3, CF2=CHCF3, CF3CH=CHF and CF3CF=CH2.

3. The membrane according to claim 1 or 2, wherein The monomer having a crosslinkable group is selected from at least one of carboxylic acids capable of polymerizing with vinyl alcohol and fluoroolefins, and vinyl ethers, vinyl esters, allyl ethers, allyl esters, acrylates and methacrylates having a crosslinkable group.

4. The membrane according to claim 1 or 2, wherein, The monomer having a crosslinkable group is selected from CH2=CHCOOH, CH(CH3)=CHCOOH, CH2=C(CH3)COOH, CH2=CH(CH2) n2 COOH, CH2=CHO-CH2-cyclo-C6H 10 -CH2OH, CH2=CHCH2O-CH2-cyclo-C6H 10 -CH2OH, CH2=CHOCH2CH2OH, CH2=CHCH2OCH2CH2OH, CH2=CHOCH2CH2CH2CH2OH, CH2=CHCH2OCH2CH2CH2CH2OH, CH2=CHCOOCH2CH2OH and CH2=C(CH3)COOCH2CH2OH, where n2 represents an integer from 1 to 10.

5. The film according to claim 1 or 2, wherein, the glass transition temperature of the fluoropolymer is 10°C or higher.

6. The membrane according to claim 1 or 2, wherein, It is formed by melt-kneading a raw material containing the non-fluororesin and the fluororesin.

7. A method for manufacturing the film according to any one of claims 1 to 6, comprising melt-kneading a raw material containing the non-fluororesin and the fluororesin to form a film, wherein the content of the fluororesin is 4.0 to 10.0% by mass relative to the total mass of the non-fluororesin, the fluorine atom content of the fluororesin is 50% by mass or less.

8. Use of the film according to any one of claims 1 to 6 as an agricultural film, a film for protecting wind power generation blades, a paint protection film for automobiles, a film for communication towers or a film for airplanes.

9. Use of the film according to any one of claims 1 to 6 as a release film, a decorative film or a packaging film.

10. Use of the film according to any one of claims 1 to 6 as a film for building structures.

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