Laminated films, greenhouse horticultural films, and woven and knitted fabrics

Abstract

The purpose of the present invention is to provide a laminate film, a film for protected horticulture, and a woven / knit fabric excellent in durabilty and capable of maintaining high light transmittance without obstructing the growth of plants.　The laminate film has a heat ray reflection layer and a surface function layer provided on at least one surface of the heat ray reflection layer. The surface function layer is formed from a resin composition containing particles and a resin. The average particle diameter of the particles is 4 μm to 10 μm, and 0.3 parts by mass to 1.5 parts by mass of the particles is included in the film with respect to 100 parts by mass of the resin.

Description

[Technical Field]

[0001] The present invention relates to a laminated film that is excellent in durability and maintains high light transmittance without interfering with plant growth, and to a film for greenhouse horticulture, a woven or knitted fabric, etc. that uses the same. [Background technology]

[0002] Films with far-infrared reflectivity and visible light transmittance have been proposed for use in agricultural greenhouses (see, for example, Patent Documents 1 and 2). However, these films are provided with reflectivity by a metal-containing layer, resulting in low visible light transmittance. Providing an ultraviolet-cutting layer has also been proposed, but this does not provide sufficient performance.

[0003] Furthermore, ultra-multilayer films that ensure visible light transmittance and block ultraviolet rays have been proposed (see, for example, Patent Document 3). However, these films use ultraviolet absorbers kneaded into the film resin, and the durability is still insufficient when used as films for agricultural greenhouses, for example.

[0004] Also, a solar radiation control film that is an ultra-multilayer film and has a heat ray reflection function has been proposed (see, for example, Patent Document 4). Also, a film for agricultural greenhouses that has a heat ray reflection function, high total light transmittance, and high light diffusion function has been proposed (see, for example, Patent Document 5). However, even these films do not provide sufficient durability in, for example, the harsh humid and hot environment inside an agricultural greenhouse.

[0005] As described above, there is still no film that fully meets the performance requirements for agricultural films, such as excellent visible light transmission and infrared reflection, and durability even in the harsh humid and hot environment inside an agricultural greenhouse. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5464567 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-206430 [Patent Document 3] Patent No. 6780636 [Patent Document 4] Patent No. 5513373 [Patent Document 5] Japanese Patent Publication No. 2020-179643 Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above circumstances, an object of the present invention is to provide a laminated film, a film for greenhouse horticulture, a woven or knitted fabric, and the like that do not block plant growth, have excellent durability, and can maintain high light transmittance. [Means for solving the problem]

[0008] The present inventors have found that the above problems can be solved by using a laminated film having a laminated structure of specific resin layers, and have completed the present invention.

[0009] That is, the present invention provides the following laminated film.

[0010] [1] A laminated film having a heat ray reflective layer and a surface functional layer on at least one surface of the heat ray reflective layer, The surface functional layer is formed from a resin composition containing particles and a resin, the particles have an average particle diameter of 4 μm to 10 μm, and the particles are contained in an amount of 0.3 parts by mass to 1.5 parts by mass per 100 parts by mass of the resin, in this laminated film.

[0011] [2] The laminated film according to [1], wherein the particles are organic particles.

[0012] [3] The laminate film according to [1] or [2], wherein the heat ray reflective layer comprises a multilayer laminate film in which at least two types of resin layers having different refractive indices are alternately laminated in the thickness direction to form 20 or more layers.

[0013] [4] The laminated film according to any one of [1] to [3], wherein the resin composition contains an ultraviolet absorber having a triazine skeleton.

[0014] [5] The laminated film according to any one of [1] to [4], wherein the resin contained in the resin composition includes a resin that is a binder component.

[0015] [6] The laminated film according to [5], wherein the resin that is the binder component includes an acrylic resin.

[0016] [7] The laminated film according to any one of [1] to [6], wherein the laminated film has an average transmittance of 70% or more at wavelengths of 400 nm to 800 nm and an average transmittance of 20% or less at wavelengths of 900 nm to 1000 nm.

[0017] The present invention also provides the following greenhouse horticultural film.

[0018] [8] A film for greenhouse horticulture, comprising the laminated film according to any one of [1] to [7].

[0019] The present invention also provides the following woven or knitted fabrics.

[0020] [9] A woven or knitted fabric comprising a narrow strip tape cut from the laminated film according to any one of [1] to [7]. [Effects of the Invention]

[0021] By having the above-mentioned constitution, the laminated film of the present invention can become a film that does not block plant growth, has excellent durability and adhesion, and maintains high light transmittance.

[0022] Furthermore, since the greenhouse horticultural film and woven / knitted fabric of the present invention use the above-mentioned laminated film, it is possible to easily suppress temperature rise inside an agricultural greenhouse or the like using the film, promote plant growth over a long period of time, and provide high durability even in harsh humid and hot outdoor environments such as those of agricultural greenhouses. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a partial front view showing an embodiment of a laminated film of the present invention. [Figure 2] FIG. 2 is a partial front view showing another embodiment of the laminated film of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments.

[0025] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0026] <Laminated film> The laminated film of the present invention is A laminated film having a heat ray reflective layer and a surface functional layer on at least one surface of the heat ray reflective layer, The surface functional layer is made of a resin composition containing particles and a resin, the particles having an average particle size of 4 μm to 10 μm, and the particles are contained in an amount of 0.3 to 1.5 parts by mass per 100 parts by mass of the resin.

[0027] In the present invention, visible light refers to light with a wavelength of 400 to 800 nm, and heat rays refers to light with a wavelength of 800 to 1400 nm.

[0028] [Heat ray reflective layer] The heat ray reflective layer of the present invention can be appropriately made of a known layer having a heat ray reflecting function. The heat ray reflective layer can be made of, for example, a multilayer laminate film in which at least two resin layers having different refractive indices are alternately laminated in the thickness direction.

[0029] The multilayer laminate film may have, for example, at least 20 outermost layers (hereinafter also referred to as a "multilayer laminate structure") in which a first resin layer (hereinafter also referred to as a "first layer") and a second resin layer (hereinafter also referred to as a "second layer") having different refractive indices are alternately stacked in the thickness direction.

[0030] The multilayer laminate structure is preferably laminated so that the heat ray reflective layer is the outermost layer.

[0031] The thickness of the heat ray reflective layer is adjusted depending on the application, but is, for example, in the range of 20 μm to 150 μm, and may be 22 μm to 100 μm, 25 μm to 80 μm, or 40 μm to 60 μm. A thin thickness has the advantage of being light and improving workability.

[0032] The multilayer laminated structure is not particularly limited as long as it satisfies the above-mentioned constitution and has the function of transmitting visible light of sunlight and selectively reflecting heat rays. Reflection by alternately laminating resin layers with different refractive indices can be designed such that the reflected wavelength is determined by the optical thickness (refractive index x physical thickness) of the resin layer, and the reflectivity is determined by the total number of resin layers and the refractive index difference between the resin layers. The selection of resin and the thickness and number of resin layers can be adjusted to achieve the desired reflection characteristics.

[0033] In order for the multilayer laminate structure to adequately transmit visible light and selectively reflect heat rays, the difference in average refractive index between the two resin layers in the in-plane direction is preferably at least 0.03. The multilayer laminate structure has at least 15 resin layers, each having an optical thickness of 100 to 400 nm, preferably 150 to 360 nm, and may have, for example, 20 or more, 40 or more, 60 or more, 80 or more, 100 or more, 15 or more, or 200 or more. While a larger number of resin layers is preferable from the standpoint of optical function, if the number is too large, the overall thickness tends to become too thick. Therefore, the number is preferably 2000 or less, more preferably 1000 or less.

[0034] The resins forming the resin layers of the multilayer laminate structure may be known per se, such as polyester, polysulfone, polyamide, polyether, polyketone, polyacrylic, polycarbonate, polyacetal, polystyrene, polyamideimide, polyarylate, polyolefin, polyfluoropolymer, polyurethane, polyarylsulfone, polyethersulfone, polyarylene sulfur, polyvinyl chloride, polyetherimide, tetrafluoroethylene, polyetherketone, etc. These are not limited to homopolymers but may also be copolymers. These may be used alone or in combination of two or more. Furthermore, since it is easy to increase the refractive index difference between resins, it is preferable that at least one of the resin layers has a condensed aromatic ring, such as a naphthalene ring, as a repeating unit, which easily increases the refractive index, and this may be present as a copolymer component.

[0035] Among these, as the resin used in the resin layer having a high refractive index (for example, as the first layer), a crystalline thermoplastic resin is preferred because it is likely to exhibit a high degree of molecular orientation by stretching, and a thermoplastic resin having a melting point of 200° C. or higher is particularly preferred. From this perspective, specific examples of the thermoplastic resin include polyester, and more preferably polyethylene naphthalate and polyethylene terephthalate.

[0036] An example in which polyethylene naphthalate is used as the resin for the first layer will be described.

[0037] As the polyethylene naphthalate, any known polyethylene naphthalate can be used as appropriate. For example, polyethylene-2,6-naphthalenedicarboxylate is preferred, and polyethylene-2,6-naphthalenedicarboxylate having a condensed aromatic ring is particularly preferred because it has a high refractive index and can be stretched at a high draw ratio.

[0038] The proportion of the ethylene naphthalenedicarboxylate component, which is a monomer component in the polyethylene naphthalate, is preferably 95 mol % to 100 mol %, more preferably 96 mol % or more, and even more preferably 97 mol % or more, based on all repeating units constituting the polyethylene naphthalate. If the proportion of the ethylene naphthalenedicarboxylate component, which is the main component, is less than the lower limit, the melting point of the polyethylene naphthalate constituting the first layer decreases, making it difficult to obtain a melting point difference with the polyethylene terephthalate constituting the second layer described below. As a result, it may be difficult to impart a sufficient refractive index difference to the biaxially stretched laminate polyester film.

[0039] Examples of copolymerization components other than the main component constituting the polyethylene naphthalate include aromatic carboxylic acids such as isophthalic acid, terephthalic acid, orthophthalic acid, naphthalenedicarboxylic acids other than the main naphthalenedicarboxylic acid, and biphenyldicarboxylic acid; aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and decanedicarboxylic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; acid components such as diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentyl glycol; alicyclic diols such as 1,4-cyclohexanedimethanol; and glycol components such as polyethylene glycol and polytetramethylene glycol.

[0040] Among the copolymerization components, at least one selected from the group consisting of isophthalic acid, terephthalic acid, neopentyl glycol, 1,4-cyclohexanedimethanol, and diethylene glycol is preferred. Among these copolymerization components, isophthalic acid and terephthalic acid are particularly preferred. These copolymerization components may be used alone or in combination of two or more.

[0041] The polyethylene naphthalate can be produced by appropriately applying known methods. For example, it can be produced by a method in which the main components, i.e., a diol component, a dicarboxylic acid component, and optionally a copolymerization component, are subjected to an esterification reaction, and then the resulting reaction product is subjected to a polycondensation reaction to form a polyester. Alternatively, it can be produced by a method in which derivatives of these raw material monomers are subjected to a transesterification reaction, and then the resulting reaction product is subjected to a polycondensation reaction to form a polyester. Furthermore, it can also be produced by a method in which two or more polyesters are melt-kneaded in an extruder and subjected to a transesterification reaction (redistribution reaction).

[0042] The intrinsic viscosity of the polyethylene naphthalate constituting the first layer is preferably 0.40 to 0.80 dL / g, and may be, for example, in the range of 0.45 to 0.75 dL / g. If the intrinsic viscosity of the polyethylene naphthalate constituting the first layer is not within this range, the difference in intrinsic viscosity from the polyethylene terephthalate constituting the second layer may become large, resulting in a disordered layer structure when an alternating laminate structure is formed, or, even if a film can be formed, reduced film formability. When two or more polyesters are used and melt-mixed in an extruder and subjected to a transesterification reaction, the intrinsic viscosity of each polyester may be within the above range.

[0043] The glass transition temperature of the polyethylene naphthalate constituting the first layer is preferably higher than the glass transition temperature of the polyethylene terephthalate constituting the second layer.

[0044] On the other hand, the resin used in the low-refractive-index resin layer (e.g., as the second layer) is not particularly limited as long as it can exhibit a sufficient refractive index difference with the high-refractive-index resin layer and maintain the necessary adhesion. For example, a resin obtained by copolymerizing the resin used in the high-refractive-index resin layer with a copolymerization component that can lower the refractive index can be used. Furthermore, since there is no need to increase the refractive index by stretching or the like, it is also possible to use an amorphous resin or a resin with a melting point sufficiently lower than that of the resin in the high-refractive-index resin layer. For example, an amorphous polyester containing an ethylene terephthalate component can be preferably used. Furthermore, polylactic acid, acrylic resin, polycarbonate, and polystyrene can also be used as the resin used in the low-refractive-index resin layer.

[0045] An example in which polyethylene terephthalate is used as the resin for the second layer will be described.

[0046] When the polyethylene terephthalate is used, the initial transparency and reflectance of the film can be increased by selecting the processing conditions during film formation, but heating during post-processing can cause crystallization, resulting in a decrease in transparency and reflectance properties.By using an amorphous polyester as the polyethylene terephthalate of the second layer, the high initial transparency and reflectance of the film can be maintained even after heating during post-processing.

[0047] The ethylene terephthalate may be, for example, a polyester containing 50 mol % to 80 mol % of ethylene terephthalate based on all repeating units of the polyethylene terephthalate constituting the second layer, and more preferably a copolymerized polyethylene terephthalate containing 55 mol % to 75 mol % of ethylene terephthalate (i.e., the copolymerization component is preferably 20 to 50 mol %, more preferably 25 to 45 mol %). The copolymerization amount may be adjusted within the above range depending on the type of copolymerization component used. For example, when the copolymerization component of the copolymerized PET is isophthalic acid or naphthalenedicarboxylic acid, the copolymerization amount is generally 30 mol % or more.

[0048] If the copolymerization amount is below the lower limit, the film is likely to crystallize and orient during film formation, making it difficult to achieve a refractive index difference with the first layer, and near-infrared reflectivity is likely to decrease. Furthermore, crystallization during film formation increases haze. On the other hand, if the copolymerization amount exceeds the upper limit, heat resistance and film formability during film formation (especially during extrusion) are likely to decrease, and if the copolymerization component is a component that imparts a high refractive index, the increase in refractive index tends to reduce the refractive index difference with the first layer. By keeping the copolymerization amount within the above range, it is possible to maintain good heat resistance and film formability while ensuring a sufficient refractive index difference with the first layer, and to impart sufficient near-infrared reflectivity.

[0049] Examples of copolymerization components preferably used in the polyethylene terephthalate constituting the second layer include acid components such as aromatic dicarboxylic acids such as isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid; aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and decanedicarboxylic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aliphatic diols such as butanediol and hexanediol; alicyclic diols such as cyclohexanedimethanol; and glycol components such as spiroglycol. Among these, isophthalic acid, 2,6-naphthalenedicarboxylic acid, cyclohexanedimethanol, and spiroglycol are preferred. When copolymerization components other than these are included, the copolymerization amount is preferably 10 mol % or less. In particular, from the viewpoints of a low refractive index and minimal molecular weight loss during extrusion, 1,4-cyclohexanedimethanol is preferred as the copolymerization component of the polyethylene terephthalate.

[0050] The intrinsic viscosity of the polyethylene terephthalate is preferably 0.4 to 1.0 dL / g, and may be, for example, in the range of 0.45 to 0.95 dL / g, or 0.5 to 0.95 dL / g. If the intrinsic viscosity of the polyethylene terephthalate constituting the second layer is not within this range, the difference in intrinsic viscosity from the polyethylene naphthalate constituting the first layer may become large, resulting in disordered layer structure when an alternate laminate structure is formed, or reduced film formability even if film formation is possible.

[0051] When two or more polyesters are used and melt-mixed in an extruder to undergo an ester interchange reaction, the intrinsic viscosity of each polyester may be within the above range.

[0052] The polyethylene terephthalate can be produced by appropriately applying known methods. For example, it can be produced by a method in which the main components, that is, an acid component, a glycol component, and a copolymerization component, are subjected to an esterification reaction, and then the resulting reaction product is subjected to a polycondensation reaction to form a polyester. It can also be produced by a method in which derivatives of these raw material monomers are subjected to a transesterification reaction, and then the resulting reaction product is subjected to a polycondensation reaction to form a polyester. Furthermore, it can also be produced by a method in which two or more polyesters are melt-kneaded in an extruder and subjected to a transesterification reaction (redistribution reaction).

[0053] The first and second layers may also contain small amounts of additives as long as the object of the present invention is not impaired. Examples of such additives include lubricants such as inert particles, colorants such as pigments and dyes, stabilizers, flame retardants, and foaming agents.

[0054] The heat ray reflective layer may have a protective layer on at least one outermost layer of the multilayer laminate structure. A preferred embodiment is a heat ray reflective layer having protective layers on both outermost layers of the multilayer laminate structure.

[0055] The protective layer preferably contains the resin used in the first layer.

[0056] The protective layer is preferably a layer mainly made of polyethylene naphthalate. Regarding polyethylene naphthalate, the description in the first layer section above can be used appropriately.

[0057] In the present invention, "mainly composed of polyethylene naphthalate" means that the protective layer contains polyethylene naphthalate in an amount of 50% by mass or more of the total amount of the constituents thereof, and may, for example, be 80% by mass or more, or 90% by mass or more.

[0058] The thickness of the protective layer is 10 μm or less, but may be, for example, 1 μm to 9 μm, 2 μm to 8 μm, 3 to 7 μm, or 4 to 5 μm.

[0059] In addition, when a plurality of protective layers are provided in the laminate film, such as when protective layers are provided on both outermost layers of the multilayer laminate structure, the thickness of the protective layer refers to the thickness of each of the protective layers.

[0060] [Surface functional layer] The surface functional layer of the present invention is a layer provided on at least one surface of the heat ray reflective layer, and is made of a resin composition containing particles and a resin.

[0061] The particles may be inorganic particles, organic particles, or organic-inorganic composite particles. Specifically, for example, particles of silica, acrylic resin, styrene resin, acrylic / styrene copolymer resin, silicone, melamine resin, benzoguanamine resin, etc. may be used. These may be used alone or in combination of two or more.

[0062] The particles are preferably organic particles, specifically, the organic particles listed above, and are more preferably acrylic resin, styrene resin, or acrylic / styrene copolymer resin, with acrylic resin particles being particularly preferred from the viewpoint of heat resistance or solvent resistance.

[0063] The particles have an average particle size of 4 μm to 10 μm, and may be, for example, 4.5 μm to 9.5 μm, 5 μm to 9 μm, 5.5 μm to 8.5 μm, 6 μm to 8 μm, 6.5 μm to 7.5 μm, or 6.7 μm to 7 μm.

[0064] In the present invention, the average particle size of the particles is measured by the following method.

[0065] First, a cross section of the surface functional layer is cut out parallel to the vertical direction using a microtome, and then a very thin layer of metal is sputtered onto the particle surface to impart conductivity to the cross section.The image is then magnified 10,000 to 30,000 times using a transmission electron microscope (TEM), and the equivalent circle diameter is determined from the image, which is then calculated using the following formula. Formula: Average particle size = Sum of the diameters of the circles equivalent to the area of ​​the measured particles / Number of measured particles (at least 100 particles)

[0066] The particle content in the surface functional layer is 0.3 to 1.5 parts by mass relative to 100 parts by mass of the resin contained in the surface functional layer, and may be, for example, 0.4 to 1.4 parts by mass, 0.5 to 1.3 parts by mass, 0.6 to 1.2 parts by mass, 0.7 to 1.1 parts by mass, 0.8 to 1 part by mass, or 0.85 to 9 parts by mass.

[0067] The particles are preferably spherical. The higher the sphericity of the spherical particles, the more preferable, and the aspect ratio is preferably 1.3 or less, and particularly preferably 1.1 or less. The particles are preferably colorless and transparent. Here, colorless and transparent means that the particles are substantially free of coloring that would reduce the color purity of the three primary colors and have excellent light transmittance.

[0068] The ratio of the thickness of the surface functional layer to the average particle size of the particles contained in the surface functional layer is 0.5 or more. By setting the thickness ratio to 0.5 or more, it is possible to prevent particles from falling off the surface functional layer. The upper limit of the thickness ratio is not particularly limited, but from the viewpoint of reducing material costs, it is preferably 3 or less, more preferably 2.5 or less, and even more preferably 2 or less.

[0069] In addition, when the average particle diameter of the particles contained in the surface functional layer is larger than the thickness of the surface functional layer (i.e., the above ratio is less than 1), the thickness of the surface functional layer is measured at a point where no particles are present.

[0070] The resin composition contains a resin as a binder component. Specific examples of the resin include acrylic resin, polyester resin, polyolefin resin, urethane resin, and fluororesin. These resins may be used alone or in combination of two or more.

[0071] The resin is the main component of the resin composition (i.e., it is contained in an amount of 50% by mass or more), and it is preferable that the resin is contained in an amount of 70% by mass or more of the entire resin composition, and it may be contained in an amount of 90% by mass or more, or 95% by mass or more.

[0072] The resin may contain a known ultraviolet absorber as appropriate, but preferably contains an ultraviolet absorber having a triazine skeleton.

[0073] As the ultraviolet absorber having a triazine skeleton, any known ultraviolet absorber can be used as long as it has a triazine skeleton in the molecule.

[0074] Examples of the ultraviolet absorber having a triazine skeleton include 2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyl-s-triazine, 2-(2-hydroxy-4-propoxy-5-methylphenyl)-4,6-bis(2,4-dimethylphenyl)-s-triazine, 2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diviphenyl-s-triazine, 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-s-triazine, 2,4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)-s-triazine, and 2,4-diphenyl-6-(2-hydroxy-4-propoxyphenyl)-s-triazine. , 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-s-triazine, 2,4-bis(2-hydroxy-4-octoxyphenyl)-6-(2,4-dimethylphenyl)-s-triazine, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-s-triazine, 2,4,6-tris(2-hydroxy-4-octoxyphenyl)-s-triazine, 2-(4-isooctyloxycarbonylethoxyphenyl)-4,6-diphenyl-s-triazine, 2-(4,6-diphenyl-s-triazin-2-yl)-5-(2-(2-ethylhexanoyloxy)ethoxy)phenol, etc. These may be used alone or in combination of two or more.

[0075] The content of the ultraviolet absorber in the weather-resistant resin layer is preferably 8 to 45 parts by mass relative to 100 parts by mass of the resin contained in the surface functional layer, and may be, for example, 10 to 40 parts by mass, 12 to 35 parts by mass, 13 to 30 parts by mass, 14 to 25 parts by mass, or 15 to 20 parts by mass.

[0076] The thickness of the surface functional layer is adjusted depending on the application, but may be, for example, in the range of 1 μm to 125 μm, for example, 2 μm to 100 μm, 3 μm to 90 μm, 5 μm to 80 μm, or 10 μm to 60 μm.

[0077] The surface functional layer may contain a small amount of additives as long as the object of the present invention is not impaired. Examples of additives include lubricants such as inert particles other than the above particles, leveling agents for improving film formation quality, colorants such as pigments and dyes, stabilizers, flame retardants, and foaming agents.

[0078] [Laminated film] The laminated film of the present invention is a laminated film having the heat ray reflective layer and a surface functional layer on at least one side of the heat ray reflective layer.

[0079] In the present invention, the spectral transmittance refers to a value measured with a spectrophotometer. The spectral transmittance was measured at wavelengths of 300 to 1800 nm at 2 nm intervals, and the spectral transmittance for each wavelength was measured. The average transmittance in each wavelength range (400 to 800 nm and 900 to 1000 nm) was then calculated. The measurements were carried out in an air atmosphere at 25°C, with the incident angle of the measurement light set to 0 degrees.

[0080] In order to obtain high total light transmittance (and light diffusibility) while retaining heat ray reflection function, the laminated film of the present invention preferably has an average transmittance at wavelengths of 400 nm to 800 nm of 70% or more, more preferably 75% or more, or even more preferably 80% or more, and preferably has an average transmittance at wavelengths of 900 nm to 1000 nm of 20% or less, more preferably 15% or less, even more preferably 10% or less, and particularly preferably 5% or less.

[0081] For example, when the laminated film of the present invention is used as a film for greenhouse horticulture, it can sufficiently supply plants with visible light, which serves as a driving source for photosynthesis.Furthermore, since the laminated film of the present invention has high total light transmittance, it is believed that it can sufficiently promote plant growth.

[0082] Furthermore, since the average heat ray transmittance is 20% or less, when the laminated film of the present invention is applied to a greenhouse film, for example, it can sufficiently block heat rays that increase the temperature inside an agricultural greenhouse. Furthermore, since the film itself does not generate much heat like a heat ray-absorbing film, it is possible to suppress the temperature rise inside the agricultural greenhouse and reduce the cost required for dehumidifying and cooling.

[0083] In the present invention, the film color b value was measured using an automatic color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., model Z-300A) in accordance with JIS Z8722. The color after weathering test treatment was also measured in the same manner. The film color b value was determined by subtracting the untreated initial value data from the data after weathering test treatment, i.e., the difference Δb.

[0084] The film color b value is preferably 5 or less, and may be, for example, 4 or less, 3 or less, 2.5 or less, or 2 or less.

[0085] In the present invention, the static friction coefficient is measured by the following method.

[0086] A fixed acrylic plate is placed on the underside of two films (each 20 cm long x 10 cm wide) made by overlapping the surface and the opposite side of the target laminate film, and a thread is placed in the center of the upper side of the two overlapping films and fixed to the acrylic plate.

[0087] Next, the acrylic plate is taken up by a slow roll (10 cm / min), and a detector is fixed to one end of the upper film (the end opposite to the direction of taking up the lower film) to detect the initial tensile force between the films. The thread used at this time weighs 200 g and has a lower area of ​​50 cm. 2 (A rectangle measuring 10cm long x 5cm wide) is used.

[0088] The static friction coefficient (μs) is calculated using the following formula: μs = (starting tension force g) / (200g load)

[0089] The static friction coefficient is preferably 0.30 to 0.65, for example, more preferably 0.35 to 0.64, and further preferably 0.37 to 0.63.

[0090] (Other layers) The laminated film may be provided with other known films or layers as appropriate, as long as they do not impair the effects of the present invention. For example, a lubricating layer, a diffusion layer, etc. may be mentioned.

[0091] For example, in order to further enhance the lubricity of the laminated film, a lubrication layer having a function of imparting lubrication may be provided as appropriate. In this case, the lubrication layer may be provided on at least one surface, preferably both surfaces, of the laminated film.

[0092] The slipping layer can be formed by coating a resin layer containing a lubricant such as fine particles having an average particle size of 0.05 to 0.5 μm or wax on the multi-layer laminate structure, or by laminating by coextrusion.

[0093] If the average particle size of the fine particles is less than 1.0 μμm, the film may lack sufficient slip properties depending on the amount of particles, while if it is greater than 10 μm, the particles may fall off from the coating film, which is undesirable.

[0094] Examples of the fine particles include organic fine particles such as polystyrene, polymethyl methacrylate, methyl methacrylate copolymer, crosslinked methyl methacrylate copolymer, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, benzoguanamine resin, and core-shell type particles in which the outer shell of polystyrene particles is covered with an acrylic resin, and inorganic fine particles such as silica, alumina, titanium dioxide, kaolin, talc, graphite, calcium carbonate, feldspar, molybdenum disulfide, carbon black, and barium sulfate. Of these, organic fine particles are preferred.

[0095] [Applications of laminated film] The laminated film of the present invention can be suitably used, for example, in the field of greenhouse horticulture, the field of construction such as window materials, and the field of transportation equipment such as automobiles, airplanes, and trains.It can also be suitably used, for example, in covers and curtains for outdoor facilities such as agricultural greenhouses, lighting equipment, display devices, storage facilities, packaging, etc.

[0096] The laminate film of the present invention can be used as is in the form of a film, or can be used after being appropriately processed. Specific examples of using the laminate film as is in the form of a film include using the laminate film by attaching it to an object (for example, a window material such as glass). Specific examples of using the laminate film after processing include using it as a woven or knitted fabric as shown below.

[0097] [Method for producing laminated film] A method for producing a laminated film according to one embodiment of the present invention will be described in detail. Note that the production method described below is merely an example, and the present invention is not limited thereto. In addition, other embodiments can be obtained by referring to the following.

[0098] The laminated film of the present invention has a heat ray reflective layer and a surface functional layer provided on at least one surface of the heat ray reflective layer.

[0099] First, the method for manufacturing the heat ray reflective layer will be described by taking as an example a case where the heat ray reflective layer has a multilayer laminate structure in which at least two types of resin layers with different refractive indices are alternately laminated.

[0100] A multilayer laminate structure according to one embodiment of the present invention can be obtained by alternately stacking the polymers constituting the first layer and the polymers constituting the second layer in a molten state using a multilayer feed block device, for example, to create an alternating laminate structure of 99 or more layers in total, and then providing protective layers on both sides of the structure.

[0101] The multilayer laminated structure may be laminated so that the thickness of each of the first and second layers has a desired gradient structure. This can be achieved, for example, by changing the spacing and length of the slits in the multilayer feedblock device. This allows light with a wide wavelength range from 900 nm to 1000 nm to be reflected.

[0102] After laminating the desired number of layers using the method described above, the laminate is extruded through a die and cooled on a casting drum to obtain a multilayer unstretched film. The multilayer unstretched film is preferably stretched at least uniaxially (such uniaxial direction is the direction along the film surface) in the direction of the film-forming machine axis (also referred to as the machine direction, length direction, or MD) or in a direction perpendicular to the machine direction in the film plane (also referred to as the transverse direction, width direction, or TD). From the viewpoint of improving mechanical properties, biaxial stretching in the machine direction and transverse direction is more preferable. The stretching temperature is preferably in the range of the glass transition temperature (Tg) of the polymer in the first layer to (Tg + 20)°C. By stretching at a temperature lower than conventional temperatures, the orientation properties of the film can be more precisely controlled.

[0103] The stretching ratio is preferably 2.0 to 6.5 times, more preferably 3.0 to 5.5 times, in both the longitudinal and transverse directions. A higher stretching ratio within this range is preferable because it reduces the variation in the refractive index of each of the first and second layers in the in-plane direction due to thinning by stretching, uniforms the optical interference in the in-plane direction of the multilayer laminate structure, and increases the difference in refractive index between the first and second layers in the stretching direction. Stretching methods that can be used include uniaxial stretching in only the longitudinal or transverse direction, sequential biaxial stretching in which longitudinal and transverse stretching are performed separately, and simultaneous biaxial stretching in which longitudinal and transverse stretching are performed simultaneously. Known stretching methods, such as rod-shaped heater heating stretching, roll heating stretching, and tenter stretching, can be used for stretching in both the longitudinal and transverse directions. However, tenter stretching is preferred from the viewpoints of reducing scratches due to contact with the rolls and increasing the stretching speed.

[0104] Furthermore, by further heat-setting the film after stretching at a temperature of (Tg) to (Tg+30)°C while toeing (relaxing) the film in the stretching direction within a range of 1 to 15%, the thermal stability (e.g., thermal shrinkage rate) of the resulting multilayer laminate structure can be highly controlled.

[0105] Next, a method for forming the surface functional layer will be described.

[0106] The surface functional layer is provided on at least one surface of the heat ray reflective layer, and may be provided directly on the heat ray reflective layer or via another layer.

[0107] The method for forming the surface functional layer is not particularly limited, and examples thereof include a coating method, a spin coating method, and a transfer method, but it is preferable to form the surface functional layer by coating.

[0108] For example, known coating techniques such as bar coating, roll coating, knife-edge coating, gravure coating, and curtain coating can be used as a method for coating and forming a surface functional layer on the surface of the heat ray reflective layer. Furthermore, before applying the surface functional layer, the heat ray reflective layer may be subjected to a surface treatment (flame treatment, corona treatment, plasma treatment, ultraviolet treatment, etc.). The coating liquid used for coating is a dispersion of the above-mentioned particles and resin, and may be an aqueous dispersion or a dispersion dispersed in an organic solvent.

[0109] When the surface functional layer is formed by coating, the coating onto the heat ray reflective layer (for example, multilayer laminate structure) can be carried out at any stage, but is preferably carried out after the manufacturing process of the multilayer laminate structure.

[0110] <Film for greenhouse horticulture> The greenhouse horticultural film of the present invention includes the laminated film.

[0111] The above-mentioned greenhouse horticultural film may be any film as long as it contains the above-mentioned laminate film, and may be composed of the above-mentioned laminate film alone, or may be provided with other known films or layers.

[0112] <Woven and knitted fabrics> The woven or knitted fabric of the present invention includes narrow strips cut from the laminated film.

[0113] The woven or knitted fabric may be any fabric containing a narrow strip of tape cut from a laminated film, and may consist of only the narrow strip of tape, or may have other known tapes or layers provided thereon.

[0114] The woven or knitted fabric may be, for example, a weft knitted or warp knitted fabric using the narrow strip tape. Alternatively, the woven or knitted fabric may be a warp knitted fabric using the narrow strip tape as an insert yarn.

[0115] The woven or knitted fabric is, for example, a fabric using the narrow strip tapes as warp or weft and filament yarns or the like as weft or warp.

[0116] The woven or knitted fabric can improve the winding properties, blocking resistance, tear resistance, durability, and other mechanical strengths of the laminated film compared to when a film consisting of only a heat ray reflective layer is used alone, for example.

[0117] Furthermore, the woven or knitted fabric can ensure breathability due to the openings formed between the thin strip tapes, filament yarns, etc. As such, the woven or knitted fabric generally has superior breathability compared to when the laminated film is used alone, and therefore can prevent the temperature difference between the cultivation area and the ceiling area at night, especially in the morning, from increasing, causing condensation on the underside of the film and droplets that fall on the plants, thereby preventing discoloration and deterioration of the fruits, leaves, flowers, etc. of the plants.

[0118] Furthermore, since the woven or knitted fabric has openings, it is possible to prevent excessive blocking of ultraviolet rays, which may be effective in improving the coloring of fruits such as eggplants during growth and in supporting normal pollination activities by bees in agricultural greenhouses.

[0119] In the woven or knitted fabric, the thickness of the filament yarn or the like can be 0.01 to 0.30 times the width of the narrow tape, and the spacing between adjacent narrow tapes can be 0.1 to 0.5 times the width of the narrow tape. In the present invention, "filament yarn or the like" refers to filament yarn or spun yarn. The filament yarn may be either monofilament yarn or multifilament yarn, and is not particularly limited.

[0120] 1 and 2, an example is a fabric in which thin strip-shaped tapes (warp threads) 11, which are formed by cutting (slitting) a laminated film into thin strips, are woven with filament yarns or the like (weft threads) 12. By specifying the thickness A of the filament yarns or the like (weft threads) 12, the width B of the thin strip-shaped tapes (warp threads) 11, the spacing C between adjacent filament yarns or the like (weft threads) 12, and the spacing D between adjacent thin strip-shaped tapes (warp threads) 11 within specific ranges, the aperture ratio of the woven or knitted fabric is kept within an appropriate range, ensuring high total light transmittance and heat ray reflectance comparable to those achieved when the laminated film is used alone, while also maintaining an appropriate range for ultraviolet transmittance. Furthermore, to ensure a tight weave, filament yarns or the like (warp threads) 13 of thickness E are interposed as warps between adjacent thin strip-shaped tapes (warp threads) 11.

[0121] More specifically, in the above-mentioned woven or knitted fabric, the thickness of the filament yarns (weft) 12 is 0.01 to 0.30 times the width of the narrow strip tapes (warp) 11, and the spacing between adjacent narrow strip tapes (warp) 11 is 0.1 to 0.5 times the width of the narrow strip tapes (warp) 11, thereby keeping the aperture ratio within an appropriate range and ensuring high total light transmittance and heat ray reflectance comparable to those when the laminated film is used alone, while also keeping the ultraviolet transmittance within an appropriate range. Note that the spacing between adjacent filament yarns (weft) 12 is preferably in the range of 1.0 to 10 mm.

[0122] The width of the narrow strip tapes (warp threads) 11 is preferably 1 to 10 mm, more preferably 2 to 6 mm, and even more preferably 3 to 5 mm. The spacing between the narrow strip tapes (warp threads) 11, i.e., the distance between the edges of adjacent narrow strip tapes (warp threads) 11, is preferably 0.2 to 1.0 mm, more preferably 0.4 to 0.8 mm, and even more preferably 0.5 to 0.7 mm. The thickness of the filament yarns or the like (weft threads) 12 is preferably 0.05 to 0.35 mm, more preferably 0.1 to 0.3 mm, and even more preferably 0.15 to 0.25 mm. By setting the width of the narrow strip tapes, the thickness of the filament yarns or the like, the spacing between adjacent filament yarns or the like, and the spacing between adjacent narrow strip tapes in the woven or knitted fabric of the present invention as described above, the porosity of the woven or knitted fabric can be kept within an appropriate range, and the ultraviolet transmittance can be kept within an appropriate range while ensuring high total light transmittance and heat ray reflectance comparable to those when the laminated film is used alone.

[0123] The woven or knitted fabric formed from the laminated film preferably has an aperture ratio of 10 to 30%. In the present invention, the "aperture ratio" is defined as the aperture ratio of a square area of ​​10 cm length and width (area 100 cm) on one surface of the woven or knitted fabric. 2 ) is observed from the surface perpendicular to the surface, the part where the back side can be seen without any obstruction is defined as an aperture, and the sum of the area of ​​the aperture (referred to as the aperture area) (S cm 2 ) and calculate the formula: [S(cm 2 ) / 100(cm 2 )] × 100.

[0124] In the woven / knitted fabric of the present invention, an open area ratio of 10% or more can improve the breathability of the woven / knitted fabric. When a skylight in the ceiling is opened at night, when photosynthesis is not occurring, to lower the temperature inside the agricultural greenhouse in preparation for the temperature rise during the next day, the air heated during the day in the lower part of the agricultural greenhouse can be released to the outside through the woven / knitted fabric. Furthermore, even when the air above the roof cools at night, particularly in the morning, condensation on the underside of the woven / knitted fabric can be prevented from forming droplets that fall on plants, causing discoloration and deterioration of the fruit, leaves, flowers, etc. of the plants, as well as deterioration of the woven / knitted fabric itself, which is preferable. Furthermore, an open area ratio of 30% or less is preferable because it can ensure the high total light transmittance and heat reflectance provided by the laminated film. [Example]

[0125] Next, the present invention will be described in detail using examples, but the present invention is not limited to the following examples. The physical properties and characteristics in the examples were measured or evaluated by the following methods. Furthermore, "parts" means "parts by mass."

[0126] Furthermore, measurements and evaluations in the examples were carried out as follows.

[0127] (1) Overall film thickness and thickness of each layer The total film thickness was determined by clamping the film sample between a spindle detector (K107C, manufactured by Anritsu Electric Co., Ltd.) and measuring the thickness at 10 different positions using a digital differential electronic micrometer (K351, manufactured by Anritsu Electric Co., Ltd.). The average value was calculated and used as the total film thickness.

[0128] The thickness of each film layer was measured by cutting the laminated film into a length of 2 mm and a width of 2 cm, fixing it in an embedding capsule, and then embedding it in epoxy resin (Epomount, manufactured by Refine Tech Co., Ltd.). The embedded sample was cut perpendicular to the width direction using a microtome (ULTRACUT UCT, manufactured by LEICA) to produce thin slices with a thickness of 5 nm. Observations and photographs were taken using a transmission electron microscope (Hitachi S-4300) at an accelerating voltage of 100 kV, and the thickness (physical thickness) of each layer was measured from the photographs.

[0129] For layers with a thickness exceeding 1 μm, the layer present inside the multilayer structure was defined as an intermediate layer, and the layer present on the outermost surface was defined as an outermost layer, and the thickness of each was measured.

[0130] Whether a layer is the first or second layer can be determined from the refractive index, but if this is difficult, it can also be determined from the electronic state through NMR analysis or TEM analysis. The refractive index of each layer can also be determined from a single-layer film that has the same composition as each layer but is thicker.

[0131] (2) Spectral transmittance The spectral transmittance was measured at wavelengths of 300 to 1800 nm at 2 nm intervals using a spectrophotometer (Shimadzu Corporation, UV3600). The spectrum of the resulting laminated film was obtained, and the spectral transmittance at each wavelength was measured. The average transmittance in each wavelength range (400 to 800 nm and 900 to 1000 nm) was then calculated.

[0132] The measurements were carried out in an air atmosphere at 25° C., with the incident angle of the measurement light set to 0 degrees.

[0133] (3) Total light transmittance The total light transmittance (TT) was measured using a haze meter (NDH-4000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7361-1.

[0134] The total light transmittance after the weathering test was also measured in the same manner.

[0135] (4) Average particle size The average particle size of the particles (also called "filler") contained in the surface functional layer was measured by the following method.

[0136] First, a cross section of the surface functional layer was cut out parallel to the longitudinal direction using a microtome, and then a very thin layer of metal was sputtered onto the particle surface to impart conductivity to the cross section.The image was then magnified 10,000 to 30,000 times using a transmission electron microscope (TEM) to determine the equivalent circle diameter, which was calculated using the following formula.The results are shown in Table 1. Formula: Average particle size = Sum of the diameters of the circles equivalent to the area of ​​the measured particles / Number of measured particles (at least 100 particles)

[0137] (5) Evaluation of film color b value The film color b value was measured using an automatic color difference meter (Nippon Denshoku Industries Co., Ltd., Model Z-300A) in accordance with JIS Z8722. The color after weathering test processing was also measured in the same way. The film color b value was calculated by subtracting the unprocessed initial value data from the data after weathering test processing, and is shown in Table 1 as Δb.

[0138] (6) Moisture and heat resistance treatment The film was cut into 50 mm square specimens, which were then left in an environmental tester set at 80°C and 80% humidity for 120 hours. The specimens were then removed and subjected to appearance and adhesion evaluations, the results of which are shown in Table 1. Tests using samples after the moist heat treatment were also used for the measurements after the weather resistance test.

[0139] (7) Adhesion evaluation after moisture and heat treatment The adhesion after the moist heat treatment was evaluated as follows: A grid of cross-cuts (100 1 mm squares) was made, and 24 mm wide cellophane tape (manufactured by Nichiban Co., Ltd.) was applied on top of the cross-cuts. The tape was then rapidly peeled off at a 90° peeling angle, and the peeled surface was observed and evaluated according to the following criteria. <Adhesion evaluation criteria> ◎: Peeling area is 0% or more and less than 5% (very good adhesion) ○: Peeling area is 5% or more and less than 50% (good adhesion) ×: Peeling area exceeds 50% (poor adhesion)

[0140] (8) Static friction coefficient of laminated film An acrylic plate was placed on the underside of two films (each 20 cm long x 10 cm wide) with the front and back surfaces of the laminated film overlapping, and a thread was placed in the center of the upper side of the two overlapping films and fixed to the acrylic plate.

[0141] Next, the acrylic plate was taken up by a slow roll (10 cm / min), and a detector was attached to one end of the upper film (the end opposite to the direction of taking up the lower film) to detect the initial tensile force between the films. The thread used at this time was 200 g in weight and had a lower surface area of ​​50 cm. 2 (a rectangle measuring 10 cm in length and 5 cm in width) was used.

[0142] The static friction coefficient (μs) was calculated using the following formula: μs = (starting tension force g) / (200g load) When the static friction coefficient of a film increases, the film's slipperiness decreases, and the film is more likely to wrinkle or have defects when wound into a roll or when handled.

[0143] [Preparation of heat ray reflective layer A] The polyester used for the first and protective layers was polyethylene-2,6-naphthalate (hereinafter referred to as "PEN") with an intrinsic viscosity (orthochlorophenol, 35°C) of 0.62 dL / g, and the polyester used for the second layer was cyclohexanedimethanol-copolymerized polyethylene terephthalate (hereinafter referred to as "PETG") with an intrinsic viscosity (orthochlorophenol, 35°C) of 0.77 dL / g, copolymerized with 30 mol% cyclohexanedimethanol.

[0144] The polyester for the first and protective layers was dried at 180°C for 5 hours and then fed to an extruder, and the PEN for the first layer was melted at 290°C. The PETG for the second layer was dried at 120°C for 10 hours and then fed to an extruder and heated to 230°C to melt it.

[0145] The first layer was then split into 137 layers of PEN and the second layer of PETG into 138 layers. The resulting laminate structure, in which the PEN and PETG layers were alternately stacked and the ratio of the maximum and minimum layer thicknesses of the first and second layers varied continuously up to 1.4 times, was then laminated using a multilayer feedblock device that laminated protective layers on both sides of the laminate structure. The laminated structure was then guided through a die and cast onto a casting drum. This resulted in an unstretched multilayer laminate film with a total of 275 layers in the laminate structure, with protective layers made of PEN on the outermost layers on both sides. The supply rate of the protective layers was adjusted so that the thickness after stretching would be as shown in Table 1. The resin extrusion rates for the first and second layers were adjusted so that the optical thickness ratio of the first and second layers in the laminate structure, excluding the protective layers, was equal.

[0146] The unstretched film obtained as described above was preheated to 120°C and further stretched 3.5 times in the machine direction by heating it between low-speed and high-speed rolls from 15 mm above using an IR heater at 900°C. It was then fed into a tenter and stretched 4.5 times in the transverse direction at 140°C. The resulting biaxially oriented film was heat-set at 190°C for 30 seconds and then toe-in (relaxed) by 1.5% in the transverse direction. The heat-reflecting layer had a thickness of 55 μm, of which the protective layers on both sides were 13 μm in total. A 2000 mm wide roll was obtained.

[0147] [Preparation of Coating Solution A and Formation of Weather-Resistant Resin Layer] A coating liquid was obtained by mixing a special acrylic resin ("UV-G13" manufactured by Nippon Shokubai Co., Ltd.), a triazine-based ultraviolet absorber ("ADK STAB (registered trademark) LA-F70" manufactured by ADEKA Corporation, molecular weight 700), polymer particles with an average particle size of 5.2 μm ("TECHPOLYMER (registered trademark) MBX-5" manufactured by Sekisui Plastics Co., Ltd.) and a solvent (toluene) in the mass ratios shown in Table 1. The resulting coating liquid was applied to the surface of the heat ray reflective polyester film using a bar coater and dried to form a coating layer with the specified thickness shown in Table 1.

[0148] [Adjustment of Coating Solution B] Coating Solution B was prepared in the same manner as Coating Solution A, except that polymer particles having an average particle diameter of 7.3 μm (manufactured by Sekisui Plastics Co., Ltd., "Techpolymer (registered trademark) MBX-8") were used instead of polymer particles having an average particle diameter of 5.2 μm. The obtained coating solution was applied to the surface of the heat ray reflective polyester film using a bar coater and dried to form a coating layer with the specified thickness shown in Table 1.

[0149] [Preparation of Coating Solution C] Coating Solution C was obtained in the same manner as Coating Solution A, except that polymer particles having an average particle diameter of 4.0 μm (manufactured by Nippon Shokubai Co., Ltd., "Eposter (registered trademark) MV1004") were used instead of the polymer particles having an average particle diameter of 5.2 μm. The obtained coating solution was applied to the surface of the heat ray reflective polyester film using a bar coater and dried to form a coating layer with the specified thickness shown in Table 1.

[0150] [Preparation of Coating Solution D] Coating Solution D was prepared in the same manner as Coating Solution A, except that the polymer particles having an average particle size of 5.2 μm and the ultraviolet absorber contained in Coating Solution A were not added. The obtained coating solution was applied to the surface of the heat ray reflective polyester film using a bar coater and dried to form a weather-resistant layer having the specified thickness shown in Table 1.

[0151] [Adjustment of Coating Solution E] Coating Solution E was prepared in the same manner as Coating Solution A, except that polymer particles having an average particle diameter of 12.1 μm (manufactured by Sekisui Chemical Co., Ltd., ``Techpolymer (registered trademark) MBX-12'') were used instead of polymer particles having an average particle diameter of 5.2 μm, and a triazine-based ultraviolet absorber (manufactured by BASF, ``Tinuvin (registered trademark) Tinuvin 326'', molecular weight 316) was used.The obtained coating solution was applied to the surface of the heat ray reflective polyester film using a bar coater and dried to form a weather-resistant layer of the specified thickness shown in Table 1.

[0152] Example 1-1 Coating Solution A was applied to Heat Ray Reflective Layer A (thickness: 55 μm) using a bar coater. This was placed in an oven and dried at 120°C for 1 minute to solidify the coating layer, yielding a laminated film. The thickness of the resulting laminated film was 69 μm (heat ray reflective layer A: 55 μm, surface functional layer: 14 μm). The resulting laminated film was evaluated using the methods described above. The results are shown in Table 1.

[0153] [Examples 1-2 to 1-4, Comparative Examples 1-1 to 1-2] Except for adjusting each component of Coating Solution A so as to obtain the values ​​shown in Table 1, a laminated film was produced in the same manner as in Example 1-1, and the same evaluations as in Example 1-1 were carried out.

[0154] [Examples 2-1 to 2-3, Comparative Examples 2-1 to 2-2] Except for adjusting each component of Coating Solution B so as to obtain the values ​​shown in Table 1, a laminated film was produced in the same manner as in Example 1-1, and the same evaluations as in Example 1-1 were carried out.

[0155] [Examples 3-1 to 3-4, Comparative Examples 3-1 to 3-3] Except for adjusting each component of Coating Solution C so as to obtain the values ​​shown in Table 1, a laminated film was produced in the same manner as in Example 1-1, and the same evaluations as in Example 1-1 were carried out.

[0156] Comparative Example 4-1 A laminated film was produced in the same manner as in Example 1-1, except that no coating layer was provided so that the values ​​shown in Table 1 were obtained, and evaluations were carried out in the same manner as in Example 1-1.

[0157] Comparative Example 4-2 Except for adjusting each component of Coating Solution D so as to obtain the values ​​shown in Table 1, a laminated film was produced in the same manner as in Example 1-1, and the same evaluations as in Example 1-1 were carried out.

[0158] Comparative Example 4-3 Except for adjusting each component of Coating Solution E so as to obtain the values ​​shown in Table 1, a laminated film was produced in the same manner as in Example 1-1, and the same evaluations as in Example 1-1 were carried out.

[0159] The above formulation and the results are shown in Table 1 below.

[0160] [Table 1]

[0161] As can be seen from Table 1, the laminated films of the examples of the present invention were superior in durability and adhesion to the laminated films of the comparative examples, and were able to maintain a high light transmittance.

Claims

1. A laminated film having a heat ray reflective layer and a surface ultraviolet absorbing layer on at least one surface of the heat ray reflective layer, The surface ultraviolet absorbing layer is The resin composition is formed from particles, a resin binder, and an ultraviolet absorber. the particles are selected from the group consisting of silica particles, organic particles, and organic-inorganic composite particles; The particles have an average particle size of 4 μm to 10 μm, the particles are contained in an amount of 0.3 parts by mass to 1.5 parts by mass per 100 parts by mass of the resin; The laminated film contains 8 to 45 parts by mass of the ultraviolet absorber per 100 parts by mass of the resin.

2. The laminated film according to claim 1 , wherein the ultraviolet absorber is an ultraviolet absorber having a triazine skeleton.

3. 3. The laminated film according to claim 1, wherein the particles are contained in an amount of 0.3 to 1.0 part by mass relative to 100 parts by mass of the resin.

4. The laminate film according to claim 1 or 2, wherein the heat ray reflective layer comprises a multilayer laminate film in which at least 20 or more layers of at least two types of resin layers having different refractive indices are alternately laminated in the thickness direction.

5. The laminated film according to claim 1 or 2, wherein the resin serving as the binder component includes an acrylic resin.

6. The laminated film has an average transmittance of 70% or more in the wavelength range of 400 nm to 800 nm and an average transmittance of 20% or less in the wavelength range of 900 nm to 1000 nm. The laminated film according to claim 1 or 2.

7. The laminated film has an average transmittance of 80% or more at wavelengths of 400 nm to 800 nm and an average transmittance of 20% or less at wavelengths of 900 nm to 1000 nm. The laminated film according to claim 1 or 2.

8. A laminated film as described in claim 1 or 2, wherein the difference Δb in film color b value of the laminated film before and after weather resistance testing is 2 or less.

9. A horticultural film comprising the laminated film according to claim 1 or 2.

10. A woven or knitted fabric comprising a narrow strip tape cut from the laminated film according to claim 1 or 2.

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