Resin film and agricultural coating material using same

Abstract

Provided is a resin film which has a higher light transmittance and / or a higher light utilization rate for plants than conventional resin films, and which is capable of promoting the growth of crops. The resin film is characterized in that the resin film contains ceramic microparticles (A), ceramic nanoparticles (B) having a particle diameter of 1 nm to 100 nm and / or ceramic microparticles (C) having a particle diameter of 1 nm to 100 nm are contained as the ceramic microparticles (A), and the amount of the ceramic microparticles (B) relative to the total mass of the ceramic microparticles (A) is less than or equal to 1% by mass and less than or equal to 100% by mass. The total content of the ceramic nanoparticles (B) and the ceramic microparticles (C) is 95% by mass or more and 100% by mass or less.

Description

Technical Field

[0001] The present invention belongs to the technical field of resin films, and more particularly, relates to a resin film suitable for use as an agricultural covering material. Background Art

[0002] In recent years, polyvinyl chloride film (hereinafter referred to as agricultural polyvinyl chloride film), polyethylene film (hereinafter referred to as agricultural polyethylene film), ethylene-vinyl acetate copolymer film (hereinafter referred to as agricultural ethylene-vinyl acetate film), polyolefin resin film (hereinafter referred to as agricultural PO), fluororesin film (hereinafter referred to as PTFE film), and biodegradable polymer film (BDP film) are preferably used as agricultural covering materials for promoting the cultivation of crops. The cultivation of economic plants using these agricultural covering materials, such as greenhouse cultivation, tunnel cultivation, and multi-cultivation, is being actively carried out (Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-193977

[0006] Patent Document 2: Japanese Patent Application Publication No. 2011-92058 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, resin films (agricultural covering materials) such as "agricultural polyvinyl chloride film", "agricultural polyethylene film", "agricultural ethylene-vinyl acetate film", "agricultural PO", "PTFE film", and "BDP film" generally have a greatly reduced light transmittance and transmit straight light with low haze, and therefore are pointed out to be unable to sufficiently promote the growth of crops. In other words, conventional resin films cannot produce the best light transmittance and / or scattered light for the growth and development of crops, and further improvement and improvement are strongly required.

[0009] The present invention has been made to solve the above-mentioned technical problems of conventional resin films, namely, the low light transmittance and light utilization efficiency are insufficient from the viewpoint of growing crops.

[0010] That is, the present invention provides a resin film having a higher light transmittance than conventional resin films, which increases the utilization rate of light used by plants and can promote the growth of crops.

[0011] Means used to solve problems

[0012] The inventors of the present invention have repeatedly conducted in-depth research to solve the above-mentioned problems of the prior art. As a result, they found that the key points are:

[0013] (1) By adding ceramic particles to the resin film, the light transmittance of the resin film can be increased and / or the light utilization rate used by plants can be increased, and when used as an agricultural covering material, the growth of crops can be promoted;

[0014] (2) This effect cannot be achieved by simply adding ceramic particles to the resin film, and the particle size of the added ceramic particles must be precisely controlled;

[0015] (3) More specifically, the added ceramic fine particles do not contain ceramic fine particles having a particle size greater than 100 nm and less than 3 μm.

[0016] The inventors have found that the problems of the conventional art described above can be solved by the following concepts (a) to (c), and have completed the resin film according to the present invention.

[0017] (a) causing the resin film to contain ceramic particles other than ceramic particles having a particle size greater than 100 nm and less than 3 μm;

[0018] (b) the resin film contains ceramic fine particles (ceramic nanoparticles) having a particle size of 100 nm or less that do not substantially cause Rayleigh scattering;

[0019] (c) The resin film contains ceramic fine particles (ceramic microparticles) having a particle size of 3 μm or more that Mie scatter the incident light but scatter most (99% or more) of the incident light forward.

[0020] That is, the above-mentioned problems are solved by the present invention described below.

[0021] [1] Resin film (X):

[0022] The resin film (X) of the present invention contains ceramic particles (A), and as the ceramic particles (A), they contain ceramic nanoparticles (B) with a particle size of greater than 1 nm and less than 100 nm and / or ceramic micron particles (C) with a particle size of greater than 3 μm and less than 20 μm, and the total content of the ceramic nanoparticles (B) and the ceramic micron particles (C) is greater than 95% by mass and less than 100% by mass relative to the total mass of the ceramic particles (A).

[0023] Furthermore, preferably, in the resin film (X) of the present invention,

[0024] The ceramic nanoparticles (B) and the ceramic microparticles (C) are silicon dioxide particles.

[0025] The ceramic fine particles (A) include hollow particles.

[0026] The content of the ceramic fine particles (A) is 0.1 mass % or more and 50 mass % or less.

[0027] [2] Agricultural covering materials (Y):

[0028] The agricultural covering material (Y) of the present invention is an agricultural covering material (Y) using the resin film (X) of the present invention.

[0029] Effects of the Invention

[0030] The resin film of the present invention has a higher light transmittance than conventional resin films, and the utilization rate of light used by plants increases, thereby promoting the growth of crops. DETAILED DESCRIPTION

[0031] Hereinafter, the mode for carrying out the present invention will be described in more detail.

[0032] The resin film of the present invention is characterized in that the resin film contains ceramic fine particles (A).

[0033] The ceramic fine particles (A) include ceramic nanoparticles (B) having a particle size of 1 nm or more and 100 nm or less and / or ceramic microparticles (C) having a particle size of 3 μm or more and 20 μm or less.

[0034] The total content of the ceramic nanoparticles (B) and the ceramic microparticles (C) is 95% by mass or more and 100% by mass or less relative to the total mass of the ceramic fine particles (A).

[0035] In addition, in this specification, "resin film" refers to a thin film formed mainly of resin. "Resin film" only needs to contain resin as the main component, and may contain other components for the purpose of manufacturing the film or for the purpose of improving the function of the film.

[0036] [1] Resin film (X):

[0037] The resin film (X) of the present invention contains ceramic particles (A), and as the ceramic particles (A), it contains ceramic nanoparticles (B) and / or ceramic microparticles (C). That is, the resin film (X) of the present invention is composed of at least a resin (matrix), contains ceramic particles (A), and as the ceramic particles (A), it contains ceramic nanoparticles (B) and / or ceramic microparticles (C).

[0038] [1-1] Ceramic particles (A):

[0039] The resin film (X) of the present invention contains ceramic fine particles (A). By making the resin film contain ceramic fine particles of a predetermined particle size, the refractive index of the resin film can be reduced, and the light transmittance of the resin film and / or the light utilization rate used by the plant can be improved.

[0040] "Ceramic" (synonymous with ceramics) is an inorganic solid material, excluding substances composed only of atoms of metal elements (metals, alloys, etc.).

[0041] Examples of ceramics include compounds mainly composed of atoms consisting of non-metallic elements and atoms consisting of metallic elements, such as metal oxides (silicon dioxide, aluminum oxide, titanium dioxide, zirconium oxide, mullite, cordierite, etc.); metal carbides (silicon carbide, etc.); metal nitrides (silicon nitride, aluminum nitride, etc.); metal fluorides (magnesium fluoride, calcium fluoride), and other naturally occurring inorganic materials (glass, cement, ceramics, etc.).

[0042] However, if the refractive index of the ceramic particles is not lower than that of a general resin film (refractive index: about 1.6), the effect of lowering the refractive index of the resin film cannot be obtained. For example, titanium dioxide, whose material itself has a refractive index of about 2.5-2.7, is higher than the refractive index of a general resin film (about 1.60), so even if the titanium dioxide is directly contained, the refractive index cannot be lowered. Therefore, the refractive index of the ceramic particles is preferably less than 1.55, and more preferably less than 1.45. As a method of lowering the refractive index of the ceramic particles, for example, the ceramic particles can be made into hollow particles described later. From this point of view, as the type of ceramic, it is preferred to use silicon dioxide, whose material itself has a refractive index as low as about 1.4.

[0043] In this specification, "microparticles" refer to particles with a particle size of nm level and particles of μm level. The "microparticles" may be primary particles or secondary particles formed by agglomeration of the primary particles. The "particle size" is obtained by, for example, observing more than 200 particles with a scanning electron microscope (SEM) and obtaining the equivalent circle diameter by image analysis of the particles, and the "average particle size" is based on the 50% diameter (D50v) in the cumulative frequency of the equivalent circle diameter obtained by image analysis of the particles. At this time, the aggregates of secondary particles formed by agglomeration of primary particles refer to the particle size of the secondary particles. The behavior of the particles as a substance is considered.

[0044] [1-2] Ceramic nanoparticles (B):

[0045] The resin film (X) of the present invention contains either or both of ceramic nanoparticles (B) and ceramic microparticles (C) as the ceramic fine particles (A).

[0046] The ceramic nanoparticles (B) do not substantially cause Rayleigh scattering. Therefore, by making the resin film contain the ceramic nanoparticles (B), it is possible to suppress a decrease in the light transmittance of the resin film caused by scattering of incident light in the resin film.

[0047] "Ceramic nanoparticles (B)" are particles with a particle size of the nm order, specifically, particles with a particle size of 1 nm or more and 100 nm or less. Among them, the ceramic nanoparticles (B) are preferably particles with a particle size of 1 nm or more and 80 nm or less, and more preferably particles with a particle size of 1 nm or more and 50 nm or less.

[0048] By setting the particle size of the ceramic nanoparticles (B) to be 1 nm or more, the aggregation of the ceramic nanoparticles (B) can be suppressed, and the ceramic nanoparticles (B) can be uniformly dispersed in the resin matrix. On the other hand, by setting the particle size of the ceramic nanoparticles (B) to be 100 nm or less, Rayleigh scattering is substantially not caused, and the reduction in the light transmittance of the resin film caused by Rayleigh scattering of the incident light in the resin film can be suppressed.

[0049] [1-3] Ceramic micron particles (C):

[0050] The ceramic microparticles (C) cause the incident light to Mie scatter, but scatter most of it forward (almost not backward). Therefore, by making the resin film contain ceramic microparticles (C), the reduction in the light transmittance of the resin film caused by the backward scattering of the light incident on the resin film can be suppressed, and the forward diffused light can be increased by forward scattering, so that the light is irradiated further forward of the resin film.

[0051] “Ceramic micron particles (C)” are particles with a particle size of μm, specifically, particles with a particle size of 3 μm or more and 20 μm or less. Among them, the ceramic micron particles (C) are preferably particles with a particle size of 4 μm or more and 15 μm or less, and more preferably particles with a particle size of 4 μm or more and 10 μm or less.

[0052] By setting the particle size of the ceramic microparticles (C) to be 3 μm or more, although the incident light is Mie scattered, most of it is scattered forward (almost not scattered backward), so that the reduction in the light transmittance of the resin film caused by Mie scattering of the incident light in the resin film can be suppressed.

[0053] On the other hand, by setting the particle size of the ceramic microparticles (C) to 20 μm or less, the formation of easily reflective crystal planes on the surface of the fine particles can be suppressed, thereby achieving an effect of reducing the reflectance of incident light.

[0054] Ceramic microparticles (C) can increase scattered light without significantly reducing light transmittance. Therefore, the resin film (X) of the present invention can provide a large amount of light, such as light in the lower part of a greenhouse, to plants even when the sun is low, by containing ceramic microparticles (C).

[0055] The resin film (X) of the present invention can be listed as the following three types: (1) a type containing ceramic nanoparticles (B) but not containing ceramic micron particles (C); (2) a type containing ceramic micron particles (C) but not containing ceramic nanoparticles (B); (3) a type containing both ceramic nanoparticles (B) and ceramic micron particles (C).

[0056] The resin film (X) of the present invention is preferably (1) a method containing ceramic nanoparticles (B) and no ceramic microparticles (C), or (3) a method containing both ceramic nanoparticles (B) and ceramic microparticles (C) among the three methods. In these methods, ceramic nanoparticles (B) are contained. Ceramic nanoparticles (B) do not cause scattering and can reduce the refractive index of the resin film, resulting in an advantage of being able to increase the light transmittance of the resin film.

[0057] Furthermore, the resin film (X) of the present invention is also preferably a method using hollow particles as ceramic particles (A). Hollow particles contain air (refractive index is about 1) in the hollow part, so the refractive index is low. That is, the refractive index of the hollow particles decreases due to the influence of the hollow part. In the resin film (X) of the present invention, the method of using hollow particles has the effect of reducing the refractive index of the ceramic particles (A) and improving the light transmittance of the resin film (X). This method is preferred in that ceramic particles with a low refractive index can be formed even when using ceramics with a high refractive index. Therefore, from the perspective of increasing the effect of improving the light transmittance of the resin film (X), the resin film (X) of the present invention preferably contains hollow ceramic nanoparticles (B) and / or hollow ceramic microparticles (C) as ceramic particles (A).

[0058] [1-4] Resin (matrix):

[0059] The resin used as the matrix of the resin film (X) of the present invention is not particularly limited, and general plastics commonly used as agricultural covering materials and the like can be used.

[0060] As the resin (matrix), for example, polysaccharides, polysaccharide ester derivatives, polyethylene, polypropylene, polystyrene, polymethylpentene, polybutylene, butadiene styrene, polyvinyl chloride, polymethacrylic styrene, polysulfone, styrene-acrylonitrile resin, acrylonitrile-butadiene resin, acrylonitrile-butadiene-acrylate resin, acrylonitrile-butadiene-styrene resin, urea-formaldehyde resin, polyethylene terephthalate, polytrimethylene terephthalate, polymethyl methacrylate, polyphenylene ether, polyphenylene sulfide, polyphenylene sulfide, polyphenylene ether ... sulphide), polyacrylonitrile, polychlorotrifluoroethylene, polyvinyl alcohol, polyvinylidene chloride, polyvinylidene fluoride, polycarbonate, polyamide, polyamideimide, polyoxymethylene, polyacetal, polyformaldehyde, polybutylene terephthalate, polytetrafluoroethylene, ethyl vinyl acetate copolymer, ethylene tetrafluoroethylene copolymer, melamine resin, polyurea, polyurethane, epoxy resin, unsaturated polyester, polyaryl sulfone, polyacrylate, hydroxybenzoic acid polyester, polyetherimide, polycyclohexylene terephthalate, polyethylene naphthalate, polyester carbonate, aromatic polyester, aliphatic polyester, polylactic acid, lactic acid polyester, cellulose ester, polyhydroxybutyrate , polybutylene terephthalate, polybutylene adipate terephthalate, polybutylene succinate, polybutylene succinate adipate, hydroxybutyric acid / 3-hydroxyhexanoic acid copolymer polyester, polyglycolic acid, polyethylene terephthalate, polyethylene terephthalate succinate, polytetramethylene adipate terephthalate, polyhydroxybutyric acid, cellulose acetate, cellulose nitrate, cellulose propionate, ethyl cellulose, bacterial cellulose, furan-formaldehyde resin, melamine-formaldehyde resin, polyimide, chitosan, cellulose, starch, polycaprolactone, starch-based copolyester, esterified starch, polyhydroxyalkanoate, polybutylene succinate adipate, polybutylene adipate terephthalate, phenolic resin, silicone, polyether, long-chain dicarboxylic acid copolymer or a combination of any one of them.

[0061] In addition, as the resin (matrix), there can be cited ultraviolet light-curing polymers, and as ultraviolet light-curing polymers, for example, acrylic compounds, epoxy compounds, urethane compounds, and silicone compounds can be preferably used. Examples of acrylic compounds include unsubstituted alkyl (meth) acrylates, such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate; substituted alkyl (meth) acrylates, such as hydroxyl, epoxy, or halogen-substituted alkyl (meth) acrylates; cyclopentenyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, polyethylene glycol di (meth) acrylate, and the like.

[0062] There is no particular restriction on the weight average molecular weight of the resin. However, it is preferably 5,000 to 400,000, and more preferably 10,000 to 250,000. From the viewpoint of coating performance, strength of the formed sheet, and operability, a resin within the above weight average molecular weight range can be preferably used.

[0063] [1-5] Structure of resin film:

[0064] Regardless of the name of the "film", as long as it is a thin film, it is included in the "resin film" of the present invention. For example, a material generally called a "film" (thickness of 250 μm or less) is acceptable, and a material called a "sheet" (thickness of 250 μm or more) or a material called a "foil" is also acceptable. In other words, there is no limit to the thickness of the resin film.

[0065] If the resin film of the present invention is used as a resin agricultural covering material, as long as it has the flexibility or softness required for covering crops and the strength of the resin film that does not break during operation, it can be used without any problem. For example, when "agricultural polyvinyl chloride film", "agricultural polyethylene film", "agricultural ethylene-vinyl acetate film", "agricultural PO", "PTFE film", "BDP film" and the like are used in plastic greenhouses and tunnels, the thickness is about 50 μm to 200 μm. If it is used as an agricultural multilayer film, a film with a thickness of about 10 μm to 75 μm can be preferably used. In addition, when hard acrylic resins, polycarbonates, acrylonitrile resins and the like are used in agricultural greenhouses, thicker films are preferably used, and films with a thickness of about 100 μm to 1000 μm can be preferably used.

[0066] In addition, the "film" is not limited to a single layer, and may be a multilayer film. In the case of a multilayer film, the composition (type and composition of components contained), thickness, etc. of each layer may be appropriately changed.

[0067] [1-6]] Composition of resin film:

[0068] In the resin film (X) of the present invention, the total content of the ceramic nanoparticles (B) and the ceramic micron particles (C) is 95% by mass or more and 100% by mass or less, preferably 98% by mass or more and 100% by mass or less, and more preferably 100% by mass, relative to the total mass of the ceramic fine particles (A). By making the total content of the ceramic nanoparticles (B) and the ceramic micron particles (C) within the above range, the light transmittance of the resin film and / or the light utilization rate used by plants can be increased, and the growth of crops can be promoted when used as an agricultural covering material.

[0069] In the resin film (X) of the present invention, the content of ceramic particles larger than 100 nm and smaller than 3 μm is limited to 5% by mass or less, preferably limited to 2% by mass or less, and more preferably limited to 0% by mass, relative to the total mass of the ceramic particles (A). By setting the content of ceramic particles larger than 100 nm and smaller than 3 μm within the above range, backscattering increases, thereby improving the light transmittance of the resin film and / or the light utilization rate used by plants, and promoting the growth of crops when used as an agricultural covering material.

[0070] In the resin film (X) of the present invention, the content of ceramic particles smaller than 1 nm and / or ceramic particles larger than 20 μm is allowed within a range of 5 mass % or less relative to the total mass of the ceramic particles (A) and not impairing the effects of the present invention and the performance of other resin films.

[0071] In the resin film (X) of the present invention, the ceramic particles (A) are silica particles. For example, when containing ceramic nanoparticles (B), the ceramic nanoparticles (B) are silica particles. Furthermore, when containing ceramic micron particles (C), the ceramic micron particles (C) are silica particles. Furthermore, when containing ceramic nanoparticles (B) and ceramic micron particles (C), the ceramic nanoparticles (B) and the ceramic micron particles (C) are both silica particles. This is preferred in terms of making the refractive index of the resin film lower than the refractive index of a general resin film and further improving the effect of improving the light transmittance of the resin film and / or the light utilization rate used by plants.

[0072] In addition, the resin film (X) of the present invention can increase the light transmittance and also increase the scattered light by containing both ceramic nanoparticles (B) and ceramic microparticles (C). In this case, the resin film (X) of the present invention contains both ceramic nanoparticles (B) and ceramic microparticles (C), and the mass ratio ((C) / (B)) of the ceramic microparticles (C) to the ceramic nanoparticles (B) is preferably 100 or less, more preferably 10 or less, and more preferably 1 or less.

[0073] The resin film (X) of the present invention preferably contains the ceramic particles (A) at a ratio of 0.1% by mass or more and 50% by mass or less, and more preferably contains the ceramic particles (A) at a ratio of 0.5% by mass or more and 20% by mass or less. By making the content of the ceramic particles (A) 0.1% by mass or more, it is easy to produce an effect of improving the light transmittance of the resin film and / or the light utilization rate used by the plant. On the other hand, by making the content of the ceramic particles (A) 50% by mass or less, it is easy to evenly disperse the ceramic particles in the resin.

[0074] The resin film (X) of the present invention is at least composed of a resin (matrix) and contains ceramic particles (A), but as needed, within the scope that does not impair the effects of the present invention, it may contain low-refractive index materials other than ceramics (such as hollow nanopolymers), materials that are colored with various organic pigments to increase the transmittance only in a specific wavelength range, ceramics that transmit wavelengths not used in fluorescent light emission and use the absorbed wavelengths as converted light, etc.

[0075] The resin film (X) of the present invention may contain a dispersant. When manufacturing the resin film (X) of the present invention, in the process of dispersing the ceramic particles (A) in the resin, a process containing a dispersant can be preferably used. By making the resin film contain a dispersant on the particle surface or in the polymer, the aggregation of the ceramic particles (A) can be suppressed.

[0076] As dispersants, organic acids, polymer compounds, surfactants, lubricants, etc. can be used. In particular, as surfactants, various well-known nonionic surfactants (polyethylene glycol nonionic surfactants, etc.), anionic surfactants (carboxylates, sulfonates, carboxylates / sulfonates, sulfates, phosphates, etc.), cationic surfactants (amine salt type cationic surfactants, quaternary ammonium salt type cationic surfactants, etc.), polyol partial ester surfactants composed of polyols and higher fatty acids, silicone surfactants, fluorine surfactants, amino acid type amphoteric surfactants, betaine type amphoteric surfactants, etc. can be listed. In addition, as lubricants for dispersing microparticles, for example, polyethylene wax, liquid paraffin, bisamide, stearic acid, zinc stearate, aliphatic alcohols, calcium stearate, barium stearate, barium ricinoleate, dibutyltin dilaurate, dibutyltin dimaleate, organic phosphoric acid metal salts, organic phosphite compounds, phenols, β-diketone compounds, etc. can be listed. From the perspective of dispersion, these lubricants can be mixed with the polymer after direct contact with the microparticles. In addition, as a method for separating the bonds between the fine particles or adjusting the size, a method of treating with an acid or alkaline solution can also be preferably used.

[0077] Examples of the surfactant serving as a dispersant include the following surfactants.

[0078] Examples thereof include sodium laurate, sodium myristate, sodium palmitate, sodium stearate, perfluorooctanoic acid, perfluorononanoic acid, sodium N-lauroyl sarcosinate, sodium cocoyl glutamate, α-sulfo fatty acid methyl ester salt, sodium caprylate, sodium caprate, sodium 1-hexanesulfonate, sodium 1-octanesulfonate, sodium 1-decanesulfonate, sodium 1-dodecanesulfonate, perfluorobutanesulfonic acid, sodium linear alkylbenzenesulfonate, sodium toluenesulfonate, sodium isopropylbenzenesulfonate, sodium octylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium naphthalenesulfonate, disodium naphthalene disulfonate, trisodium naphthalenetrisulfonate, sodium butylnaphthalenesulfonate, perfluorooctanesulfonic acid, sodium di(2-ethylhexyl)sulfosuccinate, sodium lauryl sulfate, sodium myristyl sulfate, sodium lauryl sulfate, sodium polyoxyethylene alkylphenolsulfonate, ammonium lauryl sulfate, lauryl phosphoric acid, lauryl Sodium phosphate, potassium lauryl phosphate, tetramethylammonium chloride, tetramethylammonium hydroxide, tetrabutylammonium chloride, dodecyldimethylbenzylammonium chloride, alkyltrimethylammonium chloride, octyltrimethylammonium chloride, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, alkyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzalkonium chloride, benzalkonium bromide, benzethonium chloride, dialkyldimethylammonium chloride, didecyldimethylammonium chloride, dioctadecyldimethylammonium chloride, monomethylamine hydrochloride, dimethylamine hydrochloride, trimethylamine hydrochloride, butylpyridinium chloride, dodecylpyridinium chloride, hexadecane chloride Pyridinium, lauric acid glyceryl, monostearate glyceryl, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkyl ether, pentaethylene glycol monododecyl ether, octaethylene glycol monododecyl ether, polyoxyethylene alkylphenyl ether, octylphenol ethoxylate, nonylphenol ethoxylate, polyoxyethylene polyoxypropylene glycol, polyoxyethylene glycerol fatty acid ester, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene hexyl fatty acid ester, sorbitan fatty acid ester polyethylene glycol, lauric acid diethanolamide, oleic acid diethanolamide, stearic acid diethanolamide, coconut oil fatty acid diethanolamide, octyl glucoside, decyl glucoside, lauryl glucoside, cetyl alcohol , stearyl alcohol, oleyl alcohol, lauryl dimethylaminoacetic acid betaine, stearyl dimethylaminoacetic acid betaine, dodecylaminomethyl dimethyl sulfopropyl betaine, octadecylaminomethyl dimethyl sulfopropyl betaine, cocamidopropyl betaine, cocamidopropyl hydroxysulfobetaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazoline betaine, sodium lauroyl glutamate, potassium lauroyl glutamate, lauroyl methyl-β-alanine, lauryl dimethylamine N-oxide, oleyl dimethylamine N-oxide, dodecylamine, hexadecylamine, oleylamine, oleic acid, sodium lauryl sulfate, behenylamine, coconut amine, laurylamine, stearylamine, soyamine, lauryl dimethylamine, soy dimethylamine, stearyl dimethylamine,There are no particular limitations on the material as long as it can disperse the ceramic fine particles (A) in the resin, such as palmityl dimethylamine, distearyl methylamine, tribenzylamine, trioctylamine, trioctylphosphine, polyoxyethylene oleylamine, dodecanethiol, and 1-aminodecane.

[0079] [2] Agricultural covering materials:

[0080] The agricultural covering material of the present invention uses the resin film of the present invention. The agricultural covering material (resin film) of the present invention can also be composed of inexpensive and easily available materials such as general-purpose resins and general-purpose ceramics, and the possibility of reducing the unit price of the product is also high. Therefore, the agricultural covering material of the present invention has the following advantages: agricultural practitioners can purchase resin films with high light transmittance and capable of promoting the growth of crops at a low price compared with conventional resin films.

[0081] Example

[0082] Hereinafter, the present invention will be described in more detail using examples. However, the present invention is not limited to the following examples.

[0083] [Comparative Example 1-2, Example 1-5]

[0084] Resin films with a thickness of 150 μm or 100 μm were manufactured, and the physical properties of the resin films and the growth and development of plants covered with the resin films were compared.

[0085] [1] Manufacture of resin film:

[0086] (Comparative Example 1-2)

[0087] The resin films of Comparative Examples 1 and 2 were prepared by using low-density polyethylene as the resin and not containing ceramic fine particles. As the low-density polyethylene, trade name "Petrothene" (manufactured by Tosoh Corporation) was used.

[0088] (Example 1)

[0089] As the resin film of Example 1, the same low-density polyethylene as in Comparative Example 1 was used as the resin, and a resin film containing 10% by mass of ceramic nanoparticles (B) was manufactured. As the ceramic nanoparticles (B), silica particles having an average particle size of 60 nm and a particle size range of 40 to 80 nm were used. As the low-density polyethylene, the same substance as in Comparative Example 1 was used, and as the silica particles, the trade name "HSP-6A" (average particle size of 60 nm, particle size range of 40 to 80 nm, manufactured by Fuso Chemical Industries, Ltd.) was used.

[0090] (Example 2)

[0091] As the resin film of Example 2, the same low-density polyethylene as in Example 1 was used as the resin to produce a resin film containing 10% by mass of hollow ceramic nanoparticles (B). As the hollow ceramic nanoparticles (B), hollow silica particles having an average particle size of 60 nm and a particle size range of 40 to 80 nm were used. As the low-density polyethylene, the same substance as in Comparative Example 1 was used.

[0092] The hollow silica particles are prepared as follows: A reaction apparatus equipped with a 1L four-necked flask, a stirring blade, and a water bath is prepared. A solution in which polystyrene particles having an average particle size of 20 nm and a particle size range of 10 to 30 nm are dispersed is added to the flask, methanol is added as a solvent, and a 25% ammonia solution is further added to prepare a reaction solution 1.

[0093] On the other hand, tetramethoxysilane (TMOS) and methanol were mixed to prepare a reaction solution 2. The reaction solution 2 was added three times at intervals of 30 minutes to the reaction solution 1 maintained at 30°C. The mixed solution was stirred at 250 rpm for 1 hour to form core-shell particles in which polystyrene particles as cores were coated with shells composed of silica. The mixed solution was dried on a hot plate at 150°C to obtain a powder of core-shell particles.

[0094] Thereafter, the core-shell particle powder was heat-treated at 500° C. to remove the polystyrene serving as the core, thereby producing silica-based hollow particles having an average particle diameter of 60 nm and a particle diameter range of 40 to 80 nm.

[0095] (Example 3)

[0096] As the resin film of Example 3, the same low-density polyethylene as in Example 1 was used as the resin, and a resin film containing 2% by mass of ceramic micron particles (C) was manufactured. As the ceramic micron particles (C), silica particles having an average particle size of 4 μm and a particle size range of 3 to 5 μm were used. As the low-density polyethylene, the same substance as in Comparative Example 1 was used, and as the silica particles, the trade name "SiO2 silica" (average particle size of 4 μm, particle size range of 3 to 5 μm, manufactured by High Purity Science Research Institute Co., Ltd.) was used.

[0097] (Example 4)

[0098] As the resin film of Example 4, the same low-density polyethylene as in Example 1 was used as the resin, and a resin film containing 4% by mass of ceramic nanoparticles (B) and 1% by mass of ceramic micron particles (C) (a total of 5% by mass of ceramic fine particles) was manufactured. As the ceramic nanoparticles (B), silica particles having an average particle size of 60 nm and a particle size range of 40 to 80 nm were used, and as the ceramic micron particles (C), silica particles having an average particle size of 4 μm and a particle size range of 3 to 5 μm were used. As the low-density polyethylene, the same substance as in Comparative Example 1 was used, as the silica particles having an average particle size of 60 nm and a particle size range of 40 to 80 nm, the same substance as in Example 1 was used, and as the silica particles having an average particle size of 4 μm and a particle size range of 3 to 5 μm, the same substance as in Example 3 was used.

[0099] (Example 5)

[0100] As the resin film of Example 5, the same low-density polyethylene as in Example 1 is used as the resin to manufacture a resin film containing 2% by mass of ceramic micron particles (C). As the ceramic micron particles (C), silica particles having a secondary particle size of 3 μm or more and a particle size range of 3 to 10 μm are used. For the ceramic micron particles (C), the same ceramic nanoparticles as in Example 1 are pretreated to form secondary particles formed by agglomerating primary particles, and the secondary particles are sieved to remove silica particles below 3 μm, thereby preparing silica particles having a secondary particle size of 3 μm or more and a particle size range of 3 to 10 μm.

[0101] [Evaluation method]

[0102] (Average particle size, particle size range)

[0103] More than 200 particles of the obtained silica powder were observed by a scanning electron microscope (SEM), and the particle size range was calculated based on the equivalent circle diameter obtained by image analysis of the particles, and the 50% diameter (D50v) in the cumulative frequency of the equivalent circle diameter obtained by image analysis of the particles was calculated. For commercial products, regardless of the specifications, the measurement was performed in the same manner.

[0104] (Light transmittance, diffuse light, haze)

[0105] The measurement was performed by a measurement method in accordance with JIS K 7136. As a measurement device, a haze meter "NDH4000" (manufactured by Nippon Denshoku Industries) was used.

[0106] (Fresh weight)

[0107] Vegetable seedlings (five seedlings) planted in plastic flower pots were covered with the sheets of the embodiments and comparative examples and irradiated with indoor lighting for 28 days to allow them to grow. The average weight of the five seedlings of vegetables just after harvest was measured and compared. The results are shown in Table 1.

[0108]

[0109] As shown in Table 1, the average fresh weight of vegetables increased by 13% for the resin film of Example 1, 21% for the resin film of Example 2, 5% for the resin film of Example 3, 14% for the resin film of Example 4, and 8% for the resin film of Example 5, compared with the resin film of Comparative Example 1. This is believed to be due to the increase in light transmittance of the resin film.

[0110] Among them, the average fresh weight of vegetables in the resin films of Examples 1, 2, and 4 using ceramic nanoparticles increased significantly, showing good results. In particular, the average fresh weight of vegetables in the resin film of Example 2 using hollow ceramic nanoparticles increased significantly, showing extremely good results.

[0111] [Comparative Example 3]

[0112] As the resin film of Comparative Example 3, a resin film containing 10% by mass of ceramic particles was prepared using low-density polyethylene as the resin. As the ceramic particles, silica particles having an average particle size of 1 μm and a particle size range of 500 nm to 2 μm were used. As the low-density polyethylene, the same material as in Comparative Example 1 was used, and as the silica particles, the trade name "SiO2 silica" (average particle size of 1 μm, particle size range of 500 nm to 2 μm, manufactured by High Purity Science Research Institute Co., Ltd.) was used.

[0113] The evaluation method was the same as that of Example 1. Table 2 shows the results of comparison between the resin films of Comparative Example 1 and Example 1 described above and the resin film of Comparative Example 3.

[0114]

[0115] As shown in Table 2, the light transmittance of the resin film of Comparative Example 3 was significantly lower than that of the resin film of Example 1. The haze was also significantly increased, and the reason for the decrease in light transmittance is believed to be that the backscattering caused by the ceramic particles increased and the transparency of the resin film decreased.

[0116] In addition, the resin film of Comparative Example 3 is 48%, and the average fresh weight of vegetables is reduced. It is believed that this is caused by the reduction of the light transmittance of the resin film. It can be seen that the light transmittance of the resin film will not be improved when simply containing ceramic particles, and precise control of its particle size is required. Specifically, it is important to remove ceramic particles with a particle size greater than 100nm and less than 3μm as much as possible.

[0117] [Examples 6-10]

[0118] In the same manner as in Example 1-5, a resin film having a thickness of 150 μm or a thickness of 100 μm was produced, and the physical properties of the resin film and the growth and development of the plants covered with the resin film were compared.

[0119] (Example 6)

[0120] As a resin, a resin film containing 10 mass % of ceramic nanoparticles (B) was prepared using the same low-density polyethylene as in Example 1. As ceramic nanoparticles (B), silica particles (trade name "HSP-2S", manufactured by Fuso Chemical Industries, Ltd.) having an average particle diameter of 25 nm and a particle diameter range of 20 to 40 nm were used.

[0121] (Example 7)

[0122] As the resin, the same low-density polyethylene as in Example 1 was used, and a resin film containing 10% by mass of ceramic microparticles (C) was produced. As the ceramic microparticles (C), the same ones as in Example 3 were used.

[0123] (Example 8)

[0124] As the resin, the same low-density polyethylene as in Example 1 was used, and a resin film containing 5% by mass of ceramic nanoparticles (B) was produced. As the ceramic nanoparticles (B), the same ones as in Example 1 were used.

[0125] (Example 9)

[0126] As the resin, the same low-density polyethylene as in Example 1 was used to manufacture a resin film containing 0.4% by mass of ceramic nanoparticles (B) and 0.1% by mass of ceramic microparticles (C) (a total of 0.5% by mass of ceramic microparticles). As the ceramic nanoparticles (B), the same substance as in Example 1 (average particle size of 60 nm, particle size range of 40 to 80 nm) was used, and as the ceramic microparticles (C), the same substance as in Example 3 (average particle size of 4 μm, particle size range of 3 to 5 μm) was used.

[0127] (Example 10)

[0128] As a resin, the same low-density polyethylene as in Example 1 was used to manufacture a resin film containing 10% by mass of ceramic nanoparticles (B) and 5% by mass of ceramic microparticles (C) (a total of 15% by mass of ceramic microparticles). As ceramic nanoparticles (B), the same substance as in Example 1 (average particle size of 60 nm, particle size range of 40 to 80 nm) was used, and as ceramic microparticles (C), the same substance as in Example 3 (average particle size of 4 μm, particle size range of 3 to 5 μm) was used.

[0129] For Examples 6 to 10, light transmittance, diffuse light, haze, and fresh weight were measured and compared in the same manner as above. The results are shown in Table 3.

[0130]

[0131] Industrial Applicability

[0132] The resin film of the present invention has a higher light transmittance and / or light utilization rate used by plants than conventional resin films, and can promote the growth of crops, so it can be suitable for use as an agricultural covering material. Specifically, it can be used for resin films for plastic greenhouses, resin films for tunnels, agricultural multilayer films, etc.

Claims

1. A resin film, characterized in that The resin film contains ceramic particles (A), The ceramic fine particles (A) include ceramic nanoparticles (B) having a particle size of 1 nm or more and 100 nm or less and / or ceramic microparticles (C) having a particle size of 3 μm or more and 20 μm or less. The total content of the ceramic nanoparticles (B) and the ceramic microparticles (C) is 95% by mass or more and 100% by mass or less relative to the total mass of the ceramic fine particles (A).

2. The resin film according to claim 1, characterized in that The ceramic nanoparticles (B) and the ceramic microparticles (C) are silicon dioxide particles.

3. The resin film according to claim 1 or 2, characterized in that The ceramic fine particles (A) include hollow particles.

4. The resin film according to claim 1 or 2, characterized in that The content of the ceramic fine particles (A) is 0.1 mass % or more and 50 mass % or less.

5. An agricultural covering material, characterized in that: The agricultural covering material uses the resin film according to claim 1 or 2.

6. An agricultural covering material, characterized in that: The agricultural covering material uses the resin film according to claim 3.

7. An agricultural covering material, characterized in that: The agricultural covering material uses the resin film according to claim 4.

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