JP2007282625A - Agricultural film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agricultural film having an excellent anti-fogging property, preventing the cultivating property from degradation caused by the insufficiency of the amount of light by the light scattering with water droplets and from the outgrowth of disease caused by the falling down of water droplets, and further excellent in transparency and also preventing the blocking of the coated membranes with each other. <P>SOLUTION: This agricultural film is characterized by forming a lower layer coated membrane containing a synthetic resin on the surface of a substrate film becoming the inside of the green house on being extended, and further forming an upper layer coated membrane containing an inorganic particle as a main component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an agricultural film having excellent antifogging properties and antiblocking properties.

  In recent years, semi-forcing or suppressing cultivation of agricultural crops to increase their marketability and productivity, agricultural vinyl chloride film (hereinafter referred to as agricultural bi), polyethylene, ethylene-vinyl acetate copolymer, and polyolefin Agricultural polyolefin-based resin film (hereinafter referred to as agricultural poly, agricultural vinegar), and agricultural polyethylene terephthalate resin film mainly composed of biaxially stretched polyethylene terephthalate resin. So-called house cultivation and tunnel cultivation, where useful plants are cultivated, are actively carried out. Among them, agricultural polyolefin-based resin film mainly composed of polyolefin-based resin is light because its density is smaller than that of vinyl chloride resin, and generates little toxic gas even when incinerated. Wide-width films that do not require adhesive processing have been actively used because they can be provided at low cost, and have come to be used in a form that replaces traditionally used agricultural bean.

  When cultivating plants inside the house as a form of use of these agricultural films, if the anti-fogging property inside the house is low, the cultivatability deteriorates due to lack of translucency (light quantity inside the house) due to condensation inside the house, and drops of water drops Since various problems such as the occurrence of diseases due to the occurrence of the disease, it is one of the important performances required for agricultural films to maintain better anti-fogging properties for a long period of time.

Among these agricultural films, the type that coats the antifogging paint on the film surface inside the house can provide antifogging properties for a longer period than the type in which the antifogging agent is kneaded into the base material. Currently, research is being actively carried out (for example, see Patent Document 1).
JP2001-89751

  However, as the transition from such an antifogging agent kneading type to an antifogging paint coat type proceeds, there is an increasing demand for further improvement of the antifogging level. Specifically, under winter weather conditions where cloudy weather continues and the light intensity tends to be low, the temperature difference between the inside and outside of the house is difficult to occur, especially in the unheated house usage form, so water droplet growth on the inside anti-fogging surface of the house In some cases, the amount of incident light necessary for photosynthesis of crops could not be secured sufficiently due to irregular reflection caused by water droplets. Even in such a condition where condensation is difficult to occur, it is sufficient to develop anti-fogging properties in a short period of time, to form a uniform water film by quickly flowing out water droplets, and to suppress irregular reflection due to water droplets. Because the amount of light can be secured, it is a very useful technology for agricultural producers. Under such circumstances, there has been a demand for a specific antifogging coating composition and coating technique for imparting better antifogging properties.

  On the other hand, in the agricultural film of anti-fogging paint coat type, after production, the film is wound up, when transported, stored in a processing place or warehouse, or when the user stores before spreading, There has been a problem of blocking in the presence of moisture such as condensed water and rainwater, and improvements have been demanded. This phenomenon is a phenomenon that the anti-fogging coatings imparted with hydrophilicity come into contact with each other through moisture, and it becomes difficult to peel off due to the effect of pressure and heat due to the film's own weight, which significantly reduces the commercial value of agricultural films. That was a problem.

  Although various companies have been actively researching these anti-fogging properties and preventing blocking between coatings, anti-fogging properties are improved by improving the hydrophilicity of the coating, but blocking via water is likely to occur. The balance between anti-fogging performance and anti-blocking performance is still not sufficient, such as increasing the hydrophobicity to suppress blocking, and the anti-fogging performance decreases. A specific combination of a specific base material and an antifogging paint has been demanded.

  As a result of intensive studies, the inventor forms a lower layer coating film containing a synthetic resin binder on the surface of the base film that becomes the inside of the house during expansion, and further forms an upper layer coating film containing inorganic fine particles as a main component. It was found that an agricultural film characterized in that the antifogging property was further improved and an excellent anti-blocking property was obtained, and an agricultural film balanced in both performances could be provided, and the present invention was completed. .

  Furthermore, the present invention is such that a lower layer coating film containing a synthetic resin and inorganic fine particles is formed on the surface of the base film that becomes the inside of the house during stretching, and further an upper layer coating film containing inorganic fine particles as a main component is formed. Also related to agricultural films characterized by

  The present invention has excellent anti-fogging properties, prevents cultivating due to insufficient light quantity due to light scattering by water droplets, and prevents the occurrence of diseases caused by water droplets falling, and is excellent in transparency, during warehouse storage, etc. An object of the present invention is to provide an agricultural film in which blocking between coated films before spreading is prevented. The agricultural film of the present invention may be transparent, satin or semi-satin, and can be suitably used for agricultural film applications such as house, tunnel, mulching and bag hanging.

  Hereinafter, the present invention will be described in detail.

  The present invention is characterized in that a lower layer coating film containing a synthetic resin is formed on the surface of a base film that becomes the inside of a house during stretching, and further an upper layer coating film containing inorganic fine particles as a main component is formed. In the present invention, the lower layer coating film may further contain inorganic fine particles in addition to the synthetic resin.

  In the present invention, by forming a lower coating film on the surface of the hydrophobic base resin film and further forming an upper coating film mainly composed of inorganic fine particles, the film surface is imparted with high hydrophilicity and antifogging properties. It can be greatly improved, and further functions to prevent blocking by a resin binder or the like in a conventional anti-fogging coating film. The lower layer coating film of the present invention can be mainly composed of a synthetic resin, and has a property as a binder of the upper layer coating film. In the present invention, preferably, the lower layer coating film can contain inorganic fine particles in addition to the synthetic resin. In this case, in addition to the property as a binder with an upper layer coating film, the lower layer coating film itself has a property as an antifogging coating film, and can exhibit high antifogging properties more stably. In the present invention, the term “lower coating film” is used regardless of whether the lower coating film contains inorganic fine particles or not.

  In the present invention, it is preferable to use an upper coating film mainly composed of inorganic fine particles as a lower layer coating film mainly composed of inorganic fine particles and acrylic resin and / or urethane resin.

  Moreover, the agricultural film of this invention can form a coating film other than that in addition to the said lower layer coating film and an upper layer coating film. For example, you may form the coating film which has a dustproof effect in the opposite surface which provided the lower layer coating film and the upper layer coating film of this invention. In that case, the blocking prevention effect which is the effect of this invention may be acquired also with respect to a dust-proof coating film.

  The upper layer coating film of the present invention contains inorganic fine particles as a main component. The upper layer coating film of the present invention may contain various other components within a range not impairing the object of the present invention, and can contain various components used in the lower layer coating film described later. Thus, when using components other than inorganic fine particles, such as a synthetic resin binder, a coupling agent (a silane derivative having a reactive group), a crosslinking agent, and a surfactant, the weight of the upper coating film is 20%. The range is not more than wt%, preferably not more than 10 wt%, more preferably not more than 5 wt%.

  As the inorganic fine particles, metals, metal oxides, metal hydroxides, metal sulfates, metal carbonates, metal composite hydroxides, etc., known ones are used as long as they do not impair hydrophilicity to the film surface. I can do it. In the present invention, the upper coating film is preferably formed by applying an antifogging agent composition containing inorganic fine particles to a base film. Here, when considering the production stability during coating, an inorganic colloidal sol can be preferably used.

  Examples of the inorganic colloidal sol include various inorganic aqueous colloidal particles such as silica, alumina, water-insoluble lithium silicate, zinc oxide, zirconium oxide, iron hydroxide, tin hydroxide, titanium oxide, antimony oxide, barium sulfate, and zinc antimonate. In this method, an aqueous sol dispersed in water or a hydrophilic medium can be used. Among these, silica sol and alumina sol are preferably used, and these may be used alone or in combination. Among these, inorganic fine particles with strong photocatalytic action may have an effect on the synthetic resin binder by reducing the substantial addition concentration by combining with other inorganic fine particles, or by applying surface treatment in a range that does not inhibit hydrophilicity. There is a need to reduce it.

  The inorganic colloid sol can be subjected to a surface treatment within a range that does not inhibit the imparting of hydrophilicity to the film surface in order to improve the adhesion between the inorganic colloid sols during drying or between the inorganic colloid sol and the synthetic resin binder. As a method for surface treatment on the colloidal silica surface, known methods can be used, and among them, a silane compound such as a silane coupling agent can be preferably used.

  The inorganic colloidal sol is preferably selected in the range of an average particle size of 5 to 100 nm, and within this range, two or more colloidal sols having different average particle sizes may be used in combination. If the average particle size is too large, the coating may be devitrified in white, and if the average particle size is too small, the stability of the inorganic colloidal sol may be unfavorable. The particle size of the inorganic colloidal sol can be measured by a known method such as a laser diffraction method.

The coating amount per unit area (after drying) when applying an antifogging agent composition containing an inorganic colloid sol as the upper layer coating film is preferably 0.01 to 5 g / m ² . Below this range, it is difficult to obtain good antifogging properties, and exceeding this range causes a decrease in transparency due to whitening, which is not preferable.

  Examples of the synthetic resin that can be used as the lower coating film in the present invention include acrylic resins, epoxy resins, urethane resins, and polyester resins. Moreover, when using polyolefin-type resin as a base material of this invention, it is especially preferable to use an acrylic resin and / or a urethane-type resin, More preferably, it mentions later from (a) hydrophilic acrylic polymer. (C) those made of a hydrophobic acrylic resin, and (e) those made of a hydrophobic acrylic resin and a polyurethane emulsion, each having their respective characteristics, are preferred. In the present invention, it is preferably formed by applying a composition containing a synthetic resin (hereinafter referred to as “binder resin composition”) to a base film.

  Moreover, in this invention, in addition to a synthetic resin, an inorganic fine particle can be further contained in a lower layer coating film, and thereby a high antifogging property can be obtained stably. Here, the inorganic fine particles used for the lower layer coating film of the present invention may be the same as the inorganic fine particles used for the upper layer coating film, such as metal, metal oxide, metal hydroxide, metal sulfate, metal carbonate, etc. Metal composite hydroxides can be used. Moreover, when the lower layer coating film contains inorganic fine particles, the lower layer coating film is preferably a composition containing a synthetic resin (synthetic resin binder) and inorganic fine particles (hereinafter referred to as “antifogging agent composition for lower layer coating film”). ")" Is applied to a substrate, and an inorganic colloidal sol can be preferably used.

  In the antifogging agent composition for the lower layer coating film, the inorganic colloid sol used in combination with the synthetic resin binder is blended in a weight ratio as a solid content with respect to the total solid weight of the binder resin composition. It is preferably 0.2 or more and 5 or less, preferably 0.5 or more and 4 or less. That is, if the blending amount is too small, a sufficient antifogging effect may not be exhibited. On the other hand, if the blending amount is too large, the antifogging effect is not improved in proportion to the blending amount, but also after application. A phenomenon that the formed film becomes cloudy and lowers the light transmittance of the film appears, and the film may be rough and brittle, which is not preferable.

  The acrylic resin that can be used as a synthetic resin binder includes (a) a hydrophilic acrylic polymer, and (b) a block copolymer containing a hydrophobic molecular chain block and a hydrophilic molecular chain block in one molecule. In particular, (a) is preferably excellent in compatibility with the base film of the present invention in terms of quick initial antifogging wetting, On the other hand, (c) is preferable because of excellent compatibility with the base film of the present invention.

  As the hydrophilic acrylic polymer (a), a hydroxyl group-containing vinyl monomer component is a main component (preferably 60 wt% to 99.9 wt%, more preferably 65 wt% to 95 wt%), acid Examples thereof include a copolymer containing 0.1 to 30% by weight of a group-containing vinyl monomer component, a partially neutralized product thereof, or a completely neutralized product thereof. Examples of the hydroxyl group-containing vinyl monomer component include hydroxyalkyl (meth) acrylates, such as hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- Hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) An acrylate etc. are mention | raise | lifted. These may be homopolymers, or may be copolymers of these hydroxyalkyl (meth) acrylates as main components and other monomers that can be copolymerized therewith.

  Examples of the acid group-containing monomer copolymerizable with these hydroxyalkyl (meth) acrylates include carboxylic acids, sulfonic acids, and phosphonic acids, and (meth) acrylic acid belonging to carboxylic acids is particularly preferable.

  Examples of other copolymer components include styrene, vinyl terene, vinyl chloride, vinylidene chloride, vinyl oxide, (meth) acrylic acid esters, N, N-dimethylaminoethyl (meth) acrylamide, vinyl pyridine and the like.

  Examples of the antifogging agent composition for a lower layer coating film containing a synthetic resin binder and an inorganic colloidal sol that can be used in the present invention include, for example, Japanese Patent Publication No. 63-45432, Japanese Patent Publication No. 63-45717, Japanese Patent Publication No. 64-2158. And compounds shown in Japanese Patent No. 3094296.

  As the hydrophobic acrylic resin (c), at least a total of 60% by weight of a monomer comprising an alkyl ester of acrylic acid or methacrylic acid, or a single unit of an alkyl ester of acrylic acid or methacrylic acid and an alkenylbenzene. A monomer mixture and 0 to 40% by weight of a copolymerizable α, β-ethylenically unsaturated monomer are obtained by emulsion polymerization in an aqueous medium, for example, in the presence of an emulsifier, under normal polymerization conditions. And water dispersible polymers or copolymers.

  Examples of alkyl esters of acrylic acid or methacrylic acid used in the production of hydrophobic acrylic resins include acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid-n-propyl ester, acrylic acid isopropyl ester, acrylic acid-n- Butyl ester, acrylic acid-2-ethylhexyl ester, acrylic acid decyl ester, methacrylic acid methyl ester, methacrylic acid ethyl ester, methacrylic acid-n-propyl ester, methacrylic acid isopropyl ester, methacrylic acid-n-butyl ester, methacrylic acid- 2-ethylhexyl ester, methacrylic acid decyl ester, and the like. Generally, an alkyl alkyl group having 1 to 20 carbon atoms and / or a methyl group having 1 to 20 carbon atoms is used. Acrylic acid alkyl esters are used. Examples of alkenylbenzenes include styrene, α-methylstyrene, vinyltoluene and the like.

  Examples of α, β-ethylenically unsaturated monomers used to obtain hydrophobic acrylic resins include α, β such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid. -Ethylenically unsaturated carboxylic acids; α, β-ethylenically unsaturated sulfonic acids such as ethylene sulfonic acid; 2-acrylamido-2-methylpropanoic acid; α, β-ethylenically unsaturated phosphonic acids; acrylic acid or methacrylic acid Hydroxyl group-containing vinyl monomers such as hydroxyethyl; acrylonitriles; acrylic amides; glycidyl esters of acrylic acid or methacrylic acid, and the like. These monomers may be used alone or in combination of two or more, and are preferably used in the range of 0 to 40% by weight. If the amount used is too large, the antifogging performance may be lowered, which is not preferable.

  The acrylic resin is a known emulsifier, for example, an anionic surfactant, a cationic surfactant, or a nonionic surfactant, in the presence of one or more kinds in an aqueous medium. It can be obtained by a method of emulsion polymerization, a method of polymerization using a reactive emulsifier, a method of polymerizing based on an oligo soap theory without containing an emulsifier. In the case of a polymerization method in the presence of an emulsifier, these emulsifiers are used in the range of 0.1 to 10% by weight with respect to the total amount of charged monomers. It is preferable from the viewpoint of stability.

  Examples of the polymerization initiator preferably used for the production of the acrylic resin include persulfates such as ammonium persulfate and potassium persulfate; organic peroxides such as acetyl peroxide and benzoyl peroxide. These can be used in the range of 0.1 to 10% by weight based on the total amount of monomers charged.

  It is particularly preferable to use a hydrophobic acrylic resin having a glass transition temperature of 35 to 80 ° C. If the glass transition temperature is too low, the inorganic colloidal particles are agglomerated several times and tend to be in a non-uniform dispersion state. If it is too high, it is difficult to obtain a transparent uniform coating.

  The hydrophobic acrylic resin is preferably used as an aqueous emulsion. An aqueous emulsion obtained by polymerization of each monomer in an aqueous medium may be used as it is, or may be diluted by adding a liquid dispersion medium to this, and also produced by the above polymerization. A polymer may be collected separately and re-dispersed in a liquid dispersion medium to form an aqueous emulsion.

  On the other hand, examples of the urethane-based resin that can be used in the present invention include polyether-based, polyester-based, and polycarbonate-based anionic polyurethane aqueous compositions and emulsions. Polycarbonate-based anionic polyurethane emulsions are preferred in terms of adhesion, water resistance, and scratch resistance, and further increase the water resistance, scratch resistance, antifogging time and antifogging durability of the antifogging coating. In this respect, a polycarbonate-based anionic polyurethane emulsion containing a silanol group is more preferable. These may be used alone or in combination of two or more.

  A polycarbonate-based anionic polyurethane emulsion containing a silanol group comprises a polyurethane resin containing at least one silanol group in the molecule and a strongly basic tertiary amine as a curing catalyst. Refers to a colloidal dispersion system (emulsion) in which the silanol group-containing polyurethane resin and the strongly basic tertiary amine are dissolved in the aqueous phase, or a colloidal dispersion system in which fine particles are dispersed.

  It is preferable that the amount of the polyurethane aqueous composition is 0.01 or more and 2 or less, more preferably 0.01 or more and 1 or less with respect to the hydrophobic acrylic resin in terms of solid content by weight. When it is less than 0.01, it is difficult to improve the scratch resistance, and it takes a long time until the antifogging property is exhibited, and it is difficult to exhibit a sufficient antifogging effect. In addition, when it is too much, not only the scratch resistance is difficult to improve in proportion to the blending amount, but the coating film formed after coating tends to become cloudy and lower the light transmittance, which is also disadvantageous in terms of cost. It is not preferable.

  When preparing an antifogging agent composition for forming the lower layer coating film of the present invention, an anionic surfactant, a cationic surfactant, a nonionic surfactant, a polymer surfactant, etc. A surfactant can be added.

  Anionic surfactants include fatty acid salts such as sodium oleate and potassium oleate; higher alcohol sulfates such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzene sulfones such as sodium dodecylbenzenesulfonate and sodium alkylnaphthalenesulfonate Acid salt and alkyl naphthalene sulfonate salt; naphthalene sulfonic acid formalin condensate; dialkyl sulfosuccinate salt; dialkyl phosphate salt; polyoxyethylene sulfate salt such as sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, etc. Can be mentioned.

  Cationic surfactants include: ethanolamines; laurylamine acetate, triethanolamine monostearate formate; amine salts such as stearamide ethyl diethylamine acetate; lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, dilauryldimethyl And quaternary ammonium salts such as ammonium chloride, distearyldimethylammonium chloride, lauryldimethylbenzylammonium chloride, and the like.

  Nonionic surfactants include polyoxyethylene higher alcohol ethers such as polyoxyethylene lauryl alcohol, polyoxyethylene lauryl ether and polyoxyethylene oleyl ether; polyoxyethylene such as polyoxyethylene octylphenol and polyoxyethylene nonylphenol. Alkylaryl ethers; polyoxyethylene acyl esters such as polyethylene glycol monostearate; polypropylene glycol ethylene oxide adducts; sorbitan fatty acid esters such as sorbitan monostearate, sorbitan monopalmitate, sorbitan monobenzoate; diglycerin monopalmi Diglycerol fatty acid esters such as tate and diglycerol monostearate; glycerol monostearate Glycerin fatty acid esters such as pentaerythritol monostearate, etc .; dipentaerythritol fatty acid esters such as dipentaerythritol monopalmitate; sorbitan monopalmitate half adipate, diglycerin monostearate half Sorbitan such as glutamate and diglycerin fatty acid / dibasic acid esters; or condensates thereof with alkylene oxide such as ethylene oxide and propylene on oxide such as polyoxyethylene sorbitan monolaurate and polyoxypropylene sorbitan monostearate Etc .; Polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene stearamide, etc. Carboxymethyl ethylene alkyl amine fatty acid amides; sugar esters.

  Examples of the polymer surfactant include polyacrylate, polymethacrylate, and cellulose ethers.

  By adding these surfactants, the synthetic resin binder and the inorganic colloidal sol can be easily and rapidly dispersed uniformly, and when used in combination with the inorganic colloidal sol, hydrophilicity is imparted to the surface of the hydrophobic polyolefin resin film. It fulfills the function to be granted. The addition amount of the surfactant is preferably selected in the range of 0.1 to 50 parts by weight with respect to 100 parts by weight of the solid content of the resin. If the amount of the surfactant added is too small, it takes time to sufficiently disperse the resin and the inorganic colloid sol, and the antifogging effect in combination with the inorganic colloid sol cannot be sufficiently exhibited. If the amount added is too large, the transparency of the coating will decrease due to the bleed-out phenomenon on the coating surface formed after coating, and if it is noticeable, it may cause deterioration of the blocking resistance of the coating or decrease the water resistance of the coating. .

  When preparing the anti-fogging agent composition or binder resin composition for forming the lower layer coating film of this invention, a crosslinking agent can be added. The crosslinking agent is particularly effective in crosslinking acrylic resins to improve the water resistance of the coating. Examples of the crosslinking agent include phenolic resins, amino resins, carbodiimide compounds, amine compounds, aziridine compounds, azo compounds, isocyanate compounds, epoxy compounds, silane compounds, etc., but particularly amine compounds. Aziridine compounds, epoxy compounds, silane compounds and the like can be preferably used.

  Examples of amine compounds include aliphatic polyamines such as diethylenetriamine, triethylenepentamine and hexamethylenediamine; alicyclic amines such as 3,3′-dimethyl-4,4′-diaminocyclohexylmethane and isophoronediamine; 4-4 Aromatic amines such as' -diaminodihenylmethane and m-phenylenediamine are used. Examples of the aziridine compounds include tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, trimethylolpropane-tri-β-aziridinylpropionate, tris [1- (2- Methyl) -aziridinyl] phosphine oxide, hexa [1- (2-methyl) -aziridinyl] triphosphatriazine and the like are used.

  Epoxy compounds include reaction products of bisphenol A or bisphenol F and epichlorohydrin, epoxidized novolak resins, epichlorohydrin and aliphatics produced by the reaction of a resin reaction product of phenol (or substituted phenol) and formaldehyde with epichlorohydrin. Resin-like reaction products produced from polyhydric alcohols such as glycerol, 1,4-butanediol, poly (oxypropylene) glycol or similar polyhydric alcohol components, and resins obtained by epoxidation using peracetic acid are used. The Epoxy compounds can be used in combination with tertiary amines or quaternary ammonium salts as catalysts. These crosslinking agents can be used in an amount of 0.1 to 30% by weight based on the acrylic resin solid content.

  A liquid dispersion medium can be blended with the antifogging agent composition or binder resin composition for the lower layer coating film used in the present invention, if necessary. Such a liquid dispersion medium includes a hydrophilic or water-miscible solvent containing water, water; monohydric alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin. Examples: cyclic alcohols such as benzyl alcohol; cellosolve acetates; ketones and the like. These liquid dispersion media may be used alone or in combination.

  In the antifogging agent composition prepared in the present invention, conventional additions such as an antifoaming agent, a plasticizer, a film-forming aid, a thickening agent, a coupling agent, a pigment, and a pigment dispersant are added as necessary. Agents can be mixed. Further, as a binder component other than the acrylic resin, for example, a polyether-based, polycarbonate-based, or polyester-based water-dispersible urethane resin may be mixed.

  In order to form a lower layer coating on the surface of a base film, generally a solution or a dispersion of an antifogging composition or a binder resin composition is applied to a doctor blade coating method, a roll coating method, a dip coating method, a spray coating method, a rod, respectively. A known coating method such as a coating method, a bar coating method, a knife coating method, or a brush coating method may be employed, and drying may be performed after coating. As a drying method after coating, either a natural drying method or a forced drying method may be employed. When the forced drying method is employed, the drying method is usually 50 to 250 ° C., preferably 70 to 200 ° C. Good. For heating and drying, an appropriate method such as a hot air drying method, an infrared drying method, a far infrared drying method, and an ultraviolet curing method may be employed, and it is advantageous to adopt the hot air drying method in consideration of the drying speed and stability. is there.

  In the present invention, the total thickness of the upper layer coating film and the lower layer coating film formed on the surface of the substrate film may be selected with 1/10 or less of the substrate film as a guide, but is not necessarily limited to this range. If the total thickness of the coating film is larger than 1/10 of the base film, there is a difference in flexibility between the base film and the coating film, so that a phenomenon such as peeling of the coating film from the base film is likely to occur. The phenomenon that the coating film is cracked and the strength of the base film is lowered is not preferable.

  Moreover, when the adhesiveness of a base film and a coating film is not enough, you may give surface treatment to a base film. Examples of the treatment method applied to the surface of the laminated film of the present invention include corona discharge treatment, sputter etching treatment, sodium treatment, and sandblast treatment. In the corona discharge treatment method, discharge is performed between a needle-like or knife-edge electrode and a counter electrode, and a sample is put in between, and treatment is performed, and the film surface contains oxygen such as aldehyde, acid, alcohol peroxide, ketone, ether, etc. This is a process for generating a functional group. In the sputter etching process, a sample is placed between electrodes performing low-pressure glow discharge, and a large number of fine protrusions are formed on the film by the impact of positive ions generated by the glow discharge. In the sandblasting process, fine sand is sprayed on the film surface to form a large number of fine irregularities on the surface. Among these surface treatments, corona discharge treatment is preferable from the viewpoints of adhesion to the coating layer, workability, safety, cost, and the like.

  As the base resin film in the present invention, a known thermoplastic resin used for agricultural films mixed with an additive can be used. The base resin film in the present invention may be either a single layer or a multilayer film.

  As the resin, vinyl chloride resin, low density polyethylene, linear low density polyethylene, high density polyethylene, linear low density polyethylene having a long chain branch, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, A single layer or multilayer film mainly composed of a polyolefin resin such as polyethylene terephthalate, a polyester resin such as polyethylene terephthalate, or the like can be used. When applied to a base resin film mainly composed of polyethylene terephthalate resin, polyolefin resin, and fluorine resin, the effect is remarkable and preferable. In particular, when a polyolefin resin is used, a wide and highly flexible film is obtained, which is preferable.

  Examples of the polyolefin resin used in the present invention include an α-olefin homopolymer, a copolymer of a different monomer mainly containing an α-olefin, an α-olefin and a conjugated diene or a non-conjugated diene, etc. And polyunsaturated compounds, acrylic acid, methacrylic acid, copolymers with vinyl acetate, etc., such as high density, low density or linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene- Examples include butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid copolymer. Among these, low density polyethylene having a density of 0.910 to 0.935, an ethylene-α-olefin copolymer, and an ethylene-vinyl acetate copolymer having a vinyl acetate content of 30% by weight or less have transparency and weather resistance. It is preferable as an agricultural film from the viewpoint of properties and price.

  In the present invention, an ethylene-α-olefin copolymer resin obtained by copolymerization with a metallocene catalyst can be used as at least one component of the polyolefin resin.

  This is usually referred to as metallocene polyethylene, and is a copolymer of ethylene and an α-olefin such as butene-1, hexene-1, 4-methylpentene-1, octene. It can be obtained by (Method A) or (Method B).

(Method A) JP-A-58-19309, JP-A-59-95292, JP-A-60-35005, JP-A-60-35006, JP-A-60-35007, JP-A-60-35008 , JP-A-60-35009, JP-A-61-130314, JP-A-3-163088, European Patent Application No. 420436, US Pat. No. 5,555,438 and International Publication WO91. The method described in US Pat. No. 04247, that is, a metallocene catalyst, particularly a metallocene-alumoxane catalyst, or a metallocene compound as disclosed in, for example, International Publication No. WO92 / 01723, and a metallocene A catalyst comprising a compound that reacts with a compound to form a stable ion, or further disclosed in JP-A-5-295020 and JP-A-5 Using a catalyst in which a metallocene compound is supported on an inorganic compound as described in No. 295022, etc., the main component ethylene and the secondary component α-olefin having 4 to 20 carbon atoms can be obtained. This is a method of copolymerizing so that the density of the polymer is 0.880 to 0.930 g / cm ³ . Examples of the polymerization method include a high-pressure ion polymerization method, a solution method, a slurry method, and a gas phase method. In these, it is preferable to manufacture by a high pressure ion polymerization method.

The high-pressure ion polymerization method is described in JP-A-56-18607 and JP-A-58-25106, but the pressure is 100 kg / cm ² or more, preferably 300 to 1500 kg / cm. ^{2 and produced} at a temperature of 125 ° C. or higher, preferably 150 to 200 ° C. by a high pressure ion polymerization method.

(Method B) Metallocene catalyst component and organoaluminum oxy compound catalyst component described in JP-A-6-9724, JP-A-6-136195, JP-A-6-136196, and JP-A-6-207057 In the presence of an olefin polymerization catalyst, various conditions in the gas phase, slurry, or solution liquid phase, including a particulate carrier, and optionally an organoaluminum compound catalyst component and an ionized ionic compound catalyst component In which ethylene and an α-olefin, specifically, an α-olefin having 3 to 20 carbon atoms are copolymerized so that the density of the resulting copolymer is 0.900 to 0.930 g / cm ^3. .

  A polyolefin resin polymerized by using a metallocene compound, that is, a metallocene polyethylene, is not limited to the above methods (A) and (B) in that good initial transparency and transparency persistence of the film can be obtained. Can be used.

  Polyethylene resins including these metallocene polyethylenes are classified based on temperature rising elution fractionation (TREF), MFR, density, molecular weight distribution, and other various physical properties.

Measurement of elution curve by temperature rising elution fractionation (TREF) The measurement of elution curve by temperature rising elution fractionation (TREF) is described in “Journal of Applied Polymer Science 126, 4, 217-4, 231 ( 1981) "," Polymer debate proceedings 2P1C09 (Showa 63) "and the like. That is, first, the target polyethylene is completely dissolved once in a solvent. Thereafter, it is cooled to produce a thin polymer layer on the surface of the inert carrier. Such a polymer layer is formed easily on the inner side (side closer to the surface of the inert carrier), and on the outer side is difficult to crystallize. Next, by elevating the temperature continuously or stepwise, first, at a low temperature, the polymer is eluted from an amorphous portion in the target polymer, that is, from a polymer having a high degree of short-chain branching. As the elution temperature rises, the one with a little branching degree is gradually eluted, and finally the linear part without branching is eluted to complete the measurement. The concentration of the elution component at each temperature is continuously detected, and the composition distribution of the polymer can be measured by the peak of the graph (elution curve) drawn by the elution amount and elution temperature.

  The ethylene-α-olefin copolymer used as at least one component of the polyolefin resin of the present invention exhibits the following physical properties.

Melt flow rate (MFR)
The MFR measured according to JIS-K7210 is 0.01 to 10 g / 10 min, preferably 0.1 to 5 g / 10 min. If the MFR is larger than this range, the film meanders during molding and is not stable. On the other hand, if the MFR is too smaller than this range, the resin pressure at the time of molding increases and a load is applied to the molding machine. Therefore, the increase in pressure must be suppressed by reducing the production amount, which is not practical.

Density The density measured by JIS-K7112 is 0.880 to 0.930 g / cm ³ , preferably 0.880 to 0.920 g / cm ³ . When the density is larger than this range, the transparency is deteriorated. On the other hand, if the density is smaller than this range, blocking occurs due to stickiness of the film surface, resulting in poor practicality.

Molecular weight distribution The molecular weight distribution (weight average molecular weight / number average molecular weight) determined by gel permeation chromatography (GPC) is 1.5 to 3.5, preferably 1.5 to 3.0. . When the molecular weight distribution is larger than this range, the mechanical strength is lowered, which is not preferable. If the molecular weight distribution is smaller than this range, the film meanders during molding and is not stable.

  The ethylene-vinyl acetate copolymer resin used in the present invention has a vinyl acetate content in the range of 10 to 25% by weight, preferably in the range of 12 to 20% by weight. If the vinyl acetate content is less than this range, the resulting film will be hard and will tend to wrinkle and sag when stretched in a house, which will have a negative effect on anti-fogging properties. If it is larger than the range, the melting point of the resin is low, so that the film loosens at high temperatures in summer during house extension, and is easily broken by wind and flapping with the house structure.

  The present invention is an agricultural film that is excellent in long-term weather resistance and bleed-out resistance by using an ethylene / cyclic aminovinyl compound copolymer, has good anti-fogging coating adhesion, and hardly causes anti-fogging failure due to coating peeling. Can be obtained. Compared with hindered amine weathering agents used for general agricultural films, the ethylene / cyclic aminovinyl compound copolymer not only provides an effect as a light stabilizer that significantly improves long-term weather resistance, but also prevents it. It plays a role of improving the adhesion to the surface of the coating including the cloudy coating.

  The copolymer of ethylene (A) and cyclic aminovinyl compound (B) of the present invention (hereinafter referred to as “ethylene / cyclic aminovinyl compound copolymer”) is composed of ethylene (A) and the compound of formula (1). Copolymers can be used. Since the ethylene / cyclic aminovinyl compound copolymer can be added in a large amount, the surface properties (surface tension, etc. as a solid) of the polyolefin film of the film can be changed, and the coating film adhesion can be improved. It can be suitably used for the purpose.

  In said formula (2), R1 and R2 represent a hydrogen atom or a methyl group each independently, R3 represents a hydrogen atom or a C1-C4 alkyl group. Preferably, R1 and R2 are each a hydrogen atom or a methyl group, and R3 is a hydrogen atom.

  The vinyl compound (B) represented by the formula (2) is known and can be synthesized by a known method, for example, a method described in JP-B-47-8539, JP-A-48-65180, or the like. it can.

  Representative examples of the vinyl compound (B) represented by the formula (2) include 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-1,2,2,6,6. -Pentamethylpiperidine, 4-acryloyloxy-1-ethyl-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-1-propyl-2,2,6,6-tetramethylpiperidine, 4-acryloyl Oxy-1-butyl-2,2,6,6-tetramethylpiperidine, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine, 4-methacryloyloxy-1,2,2,6,6- Pentamethylpiperidine, 4-methacryloyloxy-1-ethyl-2,2,6,6-tetramethylpiperidine, 4-methacryloyloxy-1-butyl 2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-1-propyl-2,2,6,6-tetramethyl Examples include piperidine.

  As the preferred ethylene / cyclic aminovinyl compound copolymer, the ratio of (B) to the sum of ethylene (A) and cyclic aminovinyl compound (B) is 0.0005 to 0.85 mol%, More preferably, it is 0.001 to 0.55 mol%. That is, the preferred copolymer is one having a high light stability for a low content of the vinyl monomer having a hindered amine group in the side chain (cyclic aminovinyl compound (B)). When the concentration of the cyclic aminovinyl compound (B) is 0.0005 mol%, a sufficient light stabilizing effect is exhibited. On the other hand, when it exceeds 0.85 mol%, it tends to be substantially uneconomical.

  Further, the ethylene / cyclic aminovinyl compound copolymer is such that (B) is not continuous in two or more in the copolymer, and the ratio of being isolated is 83% or more based on the total amount of (B), Preferably it is 90% or more.

  The presence of the cyclic aminovinyl compound (B) is confirmed as follows, as described in JP-A-4-80215. In 13 C-NMR (for example, JNM-GSX270 Spectrometer manufactured by JEOL Ltd.), according to a known method (for example, refer to “Chemistry Dossier (1)” pages 53 to 56 (1985)) Polyethyl acrylate (see Asakura Shoten "Polymer Analysis Handbook", page 969 (1985)) and ethylene-hydroxyethyl acrylate copolymer (Eur. Poly. J. 25, 4, 411-418 (1989) ))), The 32.9 ppm peak in the TMS standard is attributed to the methylene group in the α position from the branch point of the isolated vinyl monomer (B), and the 35.7 ppm peak It was attributed to the methylene group sandwiched between the branch points of the vinyl monomer (B). Using these two signals, the ratio of the vinyl monomer (B) present in isolation in the copolymer of ethylene (A) and vinyl monomer (B) can be calculated by the following formula.

  The proportion of the hindered amine group-containing vinyl monomers having two or more hindered amine groups that are estimated as described above is not continuous but is present in an isolated state of 83% or more based on the total amount of vinyl monomers (B) in the copolymer. Is preferred. If the proportion of vinyl monomers having hindered amine groups in the side chain is less than 83% without two or more vinyl monomers having hindered amine groups in the side chain, the light stability is relatively high In some cases, the feature of having

  The MFR (value measured according to JIS-K6760 (190 ° C., 2.16 kg load)) of the ethylene / cyclic aminovinyl compound copolymer is 0.1 to 200 g / 10 min, preferably 0.5 to 20 g / 10 minutes, more preferably 1-5 g / 10 minutes. When the MFR is less than the above range, the compatibility with the polyolefin resin is poor, and when blended, it causes visible defects in film applications such as fish eyes and boots. On the other hand, if the MFR exceeds the above range, even if the copolymer has a large molecular weight, bleeding or blooming due to diffusion loss occurs, or when it is blended with a polyolefin resin, it causes a decrease in strength of the resulting resin composition. It becomes.

  Further, the ethylene / cyclic aminovinyl compound copolymer is expressed by a ratio of the weight average molecular weight to the number average molecular weight determined by preparing a calibration curve with monodisperse polystyrene using GPC. The value is preferably in the range of 3 to 120. A particularly preferred range is 5-20.

  The ethylene / cyclic aminovinyl compound copolymer is produced by subjecting required monomers to copolymerization conditions, but can be produced by a high-pressure low-density polyethylene production apparatus. Usually produced by radical polymerization, the catalyst used is a free radical generating initiator such as dialkyl peroxide, diacyl peroxide, peroxy ester, ketone peroxide, peroxy ketal, hydroperoxide, azo Compounds and the like are useful. As the polymerization apparatus, a continuous stirring tank reactor or a continuous tube reactor generally used in the high-pressure radical polymerization method of ethylene can be used. The polymerization pressure is about 1000 to 5000 kg / cm 2, and the polymerization temperature is about 100 to 400 ° C.

  The content of the ethylene / cyclic aminovinyl compound copolymer in the polyolefin resin composition of the present invention is 2 to 10 parts by weight, preferably 2 to 6 parts by weight with respect to 100 parts by weight of the polyolefin resin. If this content is less than the above range, the weather resistance is inferior because it is inferior.

  From the viewpoint of cost, the ethylene / cyclic aminovinyl compound copolymer used in the present invention is not necessarily contained in all layers of the multilayer film, and may be contained in at least one layer. Further, the ethylene / cyclic aminovinyl compound copolymer can be used in combination with one or two or more hindered amine weathering agents that are usually used. Further, one or two or more hindered amine weathering agents which are usually used can be used for the layer not containing the ethylene / cyclic aminovinyl compound copolymer. Of course, the ethylene / cyclic aminovinyl compound copolymer may be contained in all layers, but it is, for example, contained in the innermost layer and the outermost layer (outer surface of the house), and the other layers are hindered amines usually blended for agricultural use. A light stabilizer can also be contained. Moreover, the hindered amine light stabilizer normally mix | blended for agricultural use can also be contained in the same layer with an ethylene-cyclic amino vinyl compound copolymer. In this case, the cost becomes more advantageous than the case where an ethylene / cyclic aminovinyl compound copolymer is used for all layers.

  Moreover, in the base resin film of this invention, the various additives normally used for a synthetic resin can be used together. These additives include, for example, ultraviolet absorbers, weathering agents, hindered amine compounds, infrared absorbers, heat retention agents, surfactants (including fluorosurfactants), antifoggants, fillers, and metal organic acids. Antioxidation of salt, basic organic acid salt and overbased organic acid salt, hydrotalcite compound, epoxy compound, β-diketone compound, polyhydric alcohol, halogen oxyacid salt, sulfur-based, phenol-based and phosphite-based Agents, heat stabilizers, lubricants, antistatic agents, colorants, antiblocking agents, and the like.

  Examples of hindered amine compounds that can be used include bis (1,2,2,6,6-pentamethyl-4-piperidyl) -2-butyl-2- (3,5-ditert-butyl-4-hydroxybenzyl). Malonate, tetra (2,2,6,6-tetramethyl-4-piperidyl) butanetetracarboxylate, tetra (1,2,2,6,6-pentamethyl-4-piperidyl) butanetetracarboxylate, bis (2 2,6,6-tetramethyl-4-piperidyl) .di (tridecyl) butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) .di (tridecyl) butanetetracarboxylate Rate 3,9-bis [1,1-dimethyl-2- {tris (2,2,6,6-tetramethyl-4-piperidyloxycarbonyl Xyl) butylcarbonyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9-bis [1,1-dimethyl-2- {tris (1,2,2, 6,6-pentamethyl-4-piperidyloxycarbonyloxy) butylcarbonyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, 1,5,8,12-tetrakis [4, 6-bis {N- (2,2,6,6-tetramethyl-4-piperidyl) butylamino} -1,3,5-triazin-2-yl] -1,5,8,12-tetraazadodecane 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / dimethyl succinate condensate, 2-tert-octylamino-4,6-dichloro-s-triazine / N, N ' Bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine condensate, N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine / dibromo Examples include ethane condensate.

  Examples of commercially available hindered amine compounds that can be used include TINUVIN 770, TINUVIN 780, TINUVIN 144, TINUVIN 622LD, TINUVIN NOR 371, CHIMASSORB 119FL, CHIMASSORB 944 (above, manufactured by Ciba Geigy), Sanol LS-765 (Sankyo R / K) -63, MARK LA-68, MARK LA-68, MARK LA-62, MARK LA-67, MARK LA-57, LA-900 (manufactured by Asahi Denka Co., Ltd.), UV-3346, UV-3529, UV-3581, UV-3853 (above, manufactured by Cytec Corporation) and the like. These piperidine ring-containing hindered amine compounds are used alone or in combination of two or more.

  Content of the said piperidine ring containing hindered amine compound is 0.001 to 5 weight% with respect to 100 weight% of thermoplastic resins, Preferably it is 0.01 to 1 weight%. When the content is less than 0.001% by weight, a sufficient effect cannot be obtained, and when the content is more than 5% by weight, the effect is not improved, and the physical properties of the film are deteriorated.

  From the viewpoint of cost, for example, when the hindered amine compound used in the present invention is used in a multilayer film, it is not necessarily required to be contained in all layers of the multilayer film, and it may be contained in at least one layer. For example, in the case of a multilayer film, the influence on the coating film extends from additives transferred to and transferred from other layers in addition to the additive added to the layer in contact with the coating film. Although a layer or an inner / outer layer is preferable, only an inner layer, only an intermediate layer, only an outer layer, or any combination thereof may be used.

  Examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5′-methylenebis (2-hydroxy-4-methoxybenzophenone). 2-hydroxybenzophenones such as 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-ditert-butylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-ditert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chloro Benzotriazole, 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2'-hydroxy) such as-(2'-hydroxy-3'.5'-dicumylphenyl) benzotriazole, 2,2'-methylenebis (4-tert-octyl-6-benzotriazolyl) phenol Phenyl) benzotriazoles; phenyl salicylate, resorcinol monobenzoate, 2,4-ditertiarybutylphenyl-3 ′, 5′-ditertiarybutyl-4′-hydroxybenzoate, 2,4-ditertiaryamylphenyl- Benzoates such as 3 ′, 5′-ditert-butyl-4′-hydroxybenzoate, hexadecyl-3, 5-ditert-butyl-4-hydroxybenzoate; 2-ethyl-2′-ethoxyoxanilide, 2 -Substituted oxanilides such as ethoxy-4'-dodecyloxanilide; ethyl-α-cyano-β, β-diphenylacrylate Cyanoacrylates such as methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate; 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5 Triazines such as [(hexyl) oxy] -phenol, 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol Can be given. These ultraviolet absorbers are used alone or in combination of two or more.

  The content of the ultraviolet absorber is preferably more than 0.001% by weight and less than 2% by weight, more preferably 0.01-1% by weight, based on 100% by weight of the polyolefin resin. If the content is less than the above range, the effect of improving weather resistance is low, and if it exceeds the above range, there are problems such as a decrease in transparency due to bleeding out.

  From the viewpoint of cost, for example, when used in a multilayer film, the ultraviolet absorber used in the present invention does not necessarily need to be contained in all the layers of the multilayer film, and may be contained in at least one layer. Moreover, a ultraviolet absorber can be used in combination with the 1 type, or 2 or more types of other ultraviolet absorber normally used.

  The said infrared absorber (heat retention agent) is an inorganic fine particle which has infrared absorptivity, and these can be used combining 1 type (s) or 2 or more types. The inorganic fine particles that can be used are not particularly limited, but inorganic compounds containing at least one atom selected from the components: Si 2, Al 2, Mg 3, Ca, and Li 2 can be used. For example, magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, lithium hydroxide, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, calcium sulfate, magnesium sulfate, aluminum sulfate, lithium phosphate, calcium phosphate , Magnesium silicate, calcium silicate, aluminum silicate, calcium aluminate, magnesium aluminate, sodium aluminosilicate, potassium aluminosilicate, calcium aluminosilicate, kaolin, clay, talc, mica, zeolite, hydrotalcite compound, lithium aluminum composite Hydroxides, aluminum / lithium / magnesium composite carbonate compounds, aluminum / lithium / magnesium composite silicate compounds, magnesium / aluminum Um silicon composite hydroxide, magnesium aluminum silicon composite sulfate compounds, magnesium aluminum silicon composite carbonate compound, a metal complex hydroxide salt containing more anions. These may be obtained by dehydrating crystal water.

  The infrared absorber (heat retention agent) may be a natural product or a synthetic product. The inorganic fine particles can be used without being limited by the crystal structure, crystal particle diameter, and the like.

  The method for obtaining the infrared absorber (heat retention agent) represented by the above formula (4) is not particularly limited, and commercially available products can be used. For example, DHT4A (manufactured by Kyowa Chemical Co., Ltd.), HT-P (Manufactured by Sakai Chemical Co., Ltd.), Optima (manufactured by Toda Kogyo Co., Ltd.) and Mizukarak (manufactured by Mizusawa Chemical Co., Ltd.).

  In addition, the infrared absorber (heat retention agent) has a surface of higher fatty acid such as stearic acid, higher fatty acid metal salt such as alkali metal oleate, organic sulfonic acid metal salt such as alkali metal dodecylbenzenesulfonate, Those coated with fatty acid amides, higher fatty acid esters or waxes can also be used.

  The said infrared absorber (heat retention agent) can be used individually or in combination of 2 or more types. The average particle diameter is preferably in the range of 0.05 to 15 μm, more preferably 0.1 to 10 μm. If the average particle size of the infrared absorber (heat retention agent) is smaller than the above range, the dispersibility in the resin is poor and the appearance of the film (inorganic secondary agglomerates) is deteriorated and the film appearance is deteriorated. The powdering at the time is intense and the handling is inferior. On the other hand, if the average particle size of the infrared absorber (heat retention agent) is larger than the above range, the transparency is inferior or the extruder breaker screen is clogged, resulting in poor productivity.

  The content of the infrared absorber (heat retention agent) is preferably more than 0.1% by weight and less than 15% by weight, and more preferably 1 to 12% by weight with respect to 100% by weight of the polyolefin resin. If the content is less than the above range, the effect of improving heat retention is low, and if it exceeds the above range, there are problems such as a decrease in transparency.

  Examples of the surfactant include polyhydric alcohol partial esters composed of polyhydric alcohols and higher fatty acids, including various known nonionic surfactants, anionic surfactants, and cationic surfactants. Of these, silicone-based surfactants and fluorine-based surfactants are suitable. Specific examples of such an antifogging agent include, for example, nonionic surfactants such as sorbitan monostearate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monobehenate, sorbitan / alkylene glycol condensate and fatty acid. Sorbitan surfactants such as esters and glycerol monopalmitate, glycerol monostearate, glycerol monolaurate, diglycerol monopalmitate, glycerol dipalmitate, glycerol distearate, diglycerol monopalmitate monostearate Glycerin-based surfactants such as glycerol, monoglycerate, triglycerin monostearate, triglycerin distearate or alkylene oxide adducts thereof, polyethylene glycol monostearate, polyethylene glycol Polyethylene glycol surfactants such as coal monopalmitate, polyethylene glycol alkyl phenyl ether, and other trimethylolpropane surfactants such as trimethylolpropane monostearate, and pentaerythritol monopalmitate, pentaerythritol monostearate, etc. Erythritol surfactant, alkylene oxide adduct of alkylphenol; sorbitan / glycerin condensate and fatty acid ester, sorbitan / alkylene glycol condensate and fatty acid ester; diglycerin dioleate sodium lauryl sulfate, dodecylbenzenesulfonic acid Sodium, cetyltrimethylammonium chloride, dodecylamine hydrochloride, lauric acid laurylamide ethyl phosphate It can be exemplified triethylammonium cetyl ammonium iodide, oleyl amino diethylamine hydrochloride, and those containing dodecyl pyridinium salts, etc. and their isomers.

  The above-mentioned fluorosurfactant is a surfactant in which a part or all of the surfactant is substituted with F instead of H bonded to C of the hydrophobic group of a normal surfactant, and particularly a perfluoroalkyl group or perfluoroalkenyl. A surfactant containing a group. The above various additives can be used alone or in combination of two or more. Examples of the fluorine-containing compound having a perfluoroalkyl group include an anionic fluorine-containing surfactant, a cationic fluorine-containing surfactant, an amphoteric fluorine-containing surfactant, a nonionic fluorine-containing surfactant, and a fluorine-containing oligomer. can give.

  Examples of the metal species constituting the organic acid salt, basic organic acid salt and overbased organic acid salt of the metal include Li, Na, K, Ca, Ba, Mg, Sr, Zn, Cd, Sn, Cs, Examples of the organic acid include carboxylic acid, organic phosphoric acid, and phenol. Examples of the carboxylic acid include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, Caprylic acid, neodecanoic acid, 2-ethylhexylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, isostearic acid, stearic acid, 12-hydroxystearic acid, behenic acid, montanic acid, Elaidic acid, oleic acid, linoleic acid, linolenic acid, thioglycolic acid, mercaptopropionic acid, octyl mercap Propionic acid, benzoic acid, monochlorobenzoic acid, p-tert-butylbenzoic acid, dimethylhydroxybenzoic acid, 3,5-ditert-butyl-4-hydroxybenzoic acid, toluic acid, dimethylbenzoic acid, ethylbenzoic acid, cumin Acids, n-propylbenzoic acid, acetoxybenzoic acid, salicylic acid, p-tertiary octylsalicylic acid and other monovalent carboxylic acids, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid , Divalent carboxylic acids such as sebacic acid, maleic acid, fumaric acid, citraconic acid, metaconic acid, itaconic acid, aconitic acid, thiodipropionic acid, phthalic acid, isophthalic acid, terephthalic acid, oxyphthalic acid, chlorophthalic acid, etc. Monoester or monoamide compound, butanetricarboxylic acid, butane Examples thereof include di- or triester compounds of trivalent or tetravalent carboxylic acids such as tetracarboxylic acid, hemimellitic acid, trimellitic acid, merophanic acid, and pyromellitic acid, and examples of the organic phosphoric acid include mono- or dioctylphosphoric acid. Acid, mono or didodecyl phosphoric acid, mono or dioctadecyl phosphoric acid, mono or di- (nonylphenyl) phosphoric acid, phosphonic acid nonylphenyl ester, phosphonic acid stearyl ester, etc., and the phenols include phenol, cresol , Xylenol, methylpropylphenol, methyl tert-octylphenol, ethylphenol, isopropylphenol, tert-butylphenol, n-butylphenol, diisobutylphenol, isoamylphenol, diamylphenol, isohexyl Enol, octylphenol, isooctylphenol, 2-ethylhexylphenol, tertiary octylphenol, nonylphenol, dinonylphenol, tertiary nonylphenol, decylphenol, dodecylphenol, octadecylphenol, cyclohexylphenol, phenylphenolphenol, cresol, ethylphenol, cyclohexylphenol, nonylphenol And dodecylphenol.

  Examples of the filler include silica, talc, aluminum hydroxide, hydrotalcite, calcium sulfate, calcium silicate, calcium hydroxide, and hydroxide in order to suppress stickiness of the film or to further improve heat retention. Magnesium, kaolin clay, mica, alumina, magnesium carbonate, sodium aluminate, conductive zinc oxide, lithium phosphate and the like are used. One type of these fillers may be used, or two or more types may be used in combination.

  Examples of the phenol-based antioxidant include 2,6-ditert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5-ditert-butyl-4- Hydroxyphenyl) -propionate, distearyl (3,5-ditert-butyl-4-hydroxybenzyl) phosphonate, thiodiethylene glycol bis [(3,5-ditert-butyl-4-hydroxyphenyl) propionate], 1,6 -Hexamethylenebis [(3,5-ditert-butyl-4-hydroxyphenyl) propionate], 1,6-hexamethylenebis [(3,5-ditert-butyl-4-hydroxyphenyl) propionic acid amide] 4,4′-thiobis (6-tert-butyl-m-cresol), 2,2′-methylenebis (4-methyl-6- Tributylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, 4, 4′-butylidenebis (6-tert-butyl-m-cresol), 2,2′-ethylidenebis (4,6-ditert-butylphenol), 2,2′-ethylidenebis (4-secondarybutyl-6- Tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, bis [2-tert-butyl-4-methyl-6- (2-hydroxy-3) -Tert-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate 1,3,5-tris (3,5-ditert-butyl-4-hydroxylbenzyl) isocyanurate, 1,3,5-tris (3,5-ditert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 1,3,5-tris [(3,5-ditert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, tetrakis [methylene-3- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate] methane, 2-tert-butyl-4-methyl-6- (2-acryloyloxy-3-tert-butyl-5-methylbenzyl) phenol, 3, 9- Bis [1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5. ] Undecane, triethylene glycol bis [(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], n-octadecyl 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) ) Propionate, tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane and the like.

  Examples of the sulfur-based antioxidant include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl, and distearyl, and β-alkyl mercapto of polyols such as pentaerythritol tetra (β-dodecyl mercaptopropionate). And propionic acid esters.

  Examples of the phosphite antioxidant include trisnonylphenyl phosphite, tris (2,4-ditert-butylphenyl) phosphite, tris [2-tert-butyl-4- (3-tert-butyl- 4-hydroxy-5-methylphenylthio) -5-methylphenyl] phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, monodecyl diphenyl phosphite, mono (dinonylphenyl) Bis (nonylphenyl) phosphite, di (tridecyl) pentaerythritol diphosphite, distearylpentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-ditertiarybutylphenyl) penta Erythritol diphosphie Bis (2,6-ditert-butyl-4-methylphenyl) pentaerythritol diphosphite, tetra (tridecyl) isopropylidene diphenol diphosphite, tetra (tridecyl) isopropylidenediphenol diphosphite, tetra (C 12-15 mixed alkyl) -4,4′-n-butylidenebis (2-tert-butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1,1,3-tris (2-methyl-4-hydroxy-) 5-tert-butylphenyl) butane triphosphite, tetrakis (2,4-ditert-butylphenyl) biphenylene diphosphonite, 2,2′-methylenebis (4,6-ditert-butylphenyl) (octyl) phosphite , Tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylene-di Phosphonites, 2,2-methylenebis (4,6-di -t- butyl phenyl) octyl phosphite, and the like.

  Examples of the colorant include phthalocyanine blue, phthalocyanine green, hansa yellow, alizarin lake, titanium oxide, zinc white, ultramarine blue, permanent red, quinacridone, and carbon black.

  In the base film in the present invention, inorganic fine particles, organic fine particles and the like can be used as an antiblocking agent. An inorganic filler containing at least one selected from Si, Mg, Al, Li, and Ca can be used as a constituent element component of the inorganic fine particles. Among these, diatomaceous earth, natural silica, synthetic silica, talc, mica, zeolite, and the like that can be usually used as an antiblocking agent can be suitably used. As the organic fine particles, for example, polymer beads mainly composed of a thermoplastic resin can be used. Among them, acrylate, methacrylate, styrene, nylon polymers and / or copolymers thereof can be preferably used.

  The base resin film of the present invention contains the above-mentioned components in combination, and can further contain the following optional components that can be contained in the base resin film of the present invention as required. Optional components include other stabilizers, impact resistance improvers, cross-linking agents, fillers, foaming agents, antistatic agents, nucleating agents, plate-out preventing agents, surface treatment agents, flame retardants, fluorescent agents, anti-glare agents Agents, bactericides, metal deactivators, mold release agents, pigments, processing aids and the like.

  The base resin film of the present invention is each weighed in a necessary amount for blending various additives, and blender such as ribbon blender, Banbury mixer, Henschel mixer, super mixer, single or twin screw extruder, roll, and kneading machine. Any other known blending machine or mixing machine may be used. In order to form the resin composition thus obtained into a film, a method known per se, for example, a melt extrusion molding method (including a T-die method and an inflation method), calendar processing, roll processing, extrusion molding processing, Blow molding, inflation molding, melt casting, pressure molding, paste processing, powder molding, and the like can be suitably used.

  About the base resin film thickness of this invention, the thing of the range of 0.01-1 mm is preferable at the point of intensity | strength or cost, The thing of 0.05-0.5 mm is more preferable, More preferably, 0.05-0. 2 mm. If it is less than this range, there is a problem in strength, and if it exceeds this range, molding is difficult and there is a problem in stretch workability.

  When the base resin film of the present invention is a polyolefin-based multilayer film, 3 to 5 layers are easy to balance each layer. The layer ratio constituting the three-layer film is preferably in the range of 1 / 0.5 / 1 to 1/5/1 in terms of moldability, transparency and strength, and 1/2/1 to 1/4/1. The range of is more preferable. Further, the ratio between the outer layer and the inner layer is not particularly specified, but it is preferable that the ratio is approximately the same because of the curl property of the obtained film.

  When the agricultural film according to the present invention is actually used, it is preferably stretched so that the side on which the upper layer coating film / lower layer coating film is provided becomes the inside of the house or tunnel.

  The agricultural film of the present invention has very good anti-fogging properties inside the house, prevents the deterioration of cultivation due to insufficient light quantity due to light scattering by water drops and the occurrence of diseases caused by water drop falling, Agricultural film that prevents blocking and not only provides good anti-fogging properties when extended by farmers, but can also be suitably stored in areas and seasons where condensation tends to occur during distribution. It has a good balance of performance to be provided. The agricultural film of the present invention may be transparent, pear or semi-pear. Agricultural films for house, tunnel, mulching, bag hanging, etc. (so-called agricultural poly, agricultural sacbi, agricultural PO, agricultural PET (polyethylene terephthalate) ) Etc.).

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example and a comparative example, this invention is not limited to the following examples, unless the summary is exceeded.

(1) Preparation of substrate film Polyolefin-based substrate film (PO substrate film)
As a three-layer inflation molding apparatus, a 100 mmφ (made by Pla Koken Co., Ltd.) was used for a three-layer die, and the extruder used two 30 mmφ (made by Pla Giken Co., Ltd.) tube outer layers and an intermediate layer of 40 mmφ (Plastic Co., Ltd.). Manufactured by Giken Co., Ltd.) Outer inner layer extruder temperature 180 ° C., intermediate layer extruder temperature 170 ° C., die temperature 180-190 ° C., blow ratio 2.0-3.0, take-off speed 3-7 m / min, thickness 0 A three-layer laminated film composed of the components shown in Table 1 at 15 mm was obtained. Since these films are used with the end of the tube cut open when the house is stretched, the tube outer layer during film formation becomes the inner layer (inner surface) of the house when stretched when unfolded.

[Composition] Addition amounts are as described in each table.
HP-LDPE: Branched polyethylene produced with a high-pressure radical catalyst (MFR: 1.1 g / 10 min, density 0.920) Novatec LD “YF30” manufactured by Nippon Polychem
Metallocene PE: Ethylene / α-olefin copolymer produced with a metallocene catalyst (MFR: 2 g / 10 min, density 0.907) Kernel “KF270” manufactured by Nippon Polychem
EVA (1): ethylene-vinyl acetate copolymer (vinyl acetate content 5% by weight, MFR 2 g / 10 min)
EVA (2): ethylene-vinyl acetate copolymer (vinyl acetate content 15% by weight, MFR 2 g / 10 min)
UV absorber A: Cytec's triaryltriazine UV absorber "UV1164"
Synthetic hydrotalcite A: “DHT4A” manufactured by Kyowa Chemical Co., Ltd.
Light Stabilizer A: Light stabilizer “Chimassorb 944” manufactured by Ciba Specialty Chemicals
Light Stabilizer A: Light Stabilizer “tinuvin NOR 371” manufactured by Ciba Specialty Chemicals
Ethylene / Cyclic aminovinyl copolymer: “Novatech LD · XJ100H” manufactured by Nippon Polyethylene Co., Ltd. MFR = 3 g / 10 min (190 ° C., JIS-K6760) Density = 0.931 g / cm ³ (JIS-K6760) Cyclic amino Vinyl compound content = 5.1% by weight (0.7 mol%) Percentage of cyclic aminovinyl compound present in isolation = 90 mol% Melting point = 111 ° C.

PET base film As the base polyethylene terephthalate film, PET film “OHW” (150 μm thickness) manufactured by Teijin DuPont Films Ltd. was used.

(2) Surface treatment of substrate film The surface of the obtained substrate film corresponding to the inside of the house was subjected to corona discharge treatment at a discharge voltage of 120 V, a discharge current of 4.7 A, and a line speed of 10 m / min, and “wetting index” according to JIS-K6768. Was measured and confirmed.

(3) Preparation of coating solution composition for lower layer coating film Antifoggant composition A to C by blending inorganic colloid sol (silica sol and / or alumina sol), thermoplastic resin, crosslinking agent and liquid dispersion medium shown below. Thus, coating liquid compositions such as binder resin compositions A and B were obtained.

The antifogging agent composition for the lower layer coating film was as follows.
<Anti-fogging agent composition A: Use of hydrophobic acrylic binder>
Inorganic colloidal sol 1 (Snowtex ZL) 3.0
Inorganic colloidal sol 2 (Snowtex 20L) 3.0
Thermoplastic resin (GD88: hydrophobic acrylic binder resin) 4.0
Crosslinking aid (EB10) 0.1
Cross-linking agent (EA55) 0.2
Dispersion medium (water / IPA = 6/4) 90
(Note) The amount of inorganic colloidal sol is indicated by the amount of inorganic particles, and the amount of thermoplastic resin is indicated by the solid content of the polymer.
Snowtex ZL: Nissan Chemical Co., Ltd. Snowtex 20L: Nissan Chemical Co., Ltd. GD88: Japan NSC Co., Ltd. acrylic emulsion EB10: Japan NSC Co., Ltd. EA55: Japan NSC Co., Ltd.

<Anti-fogging agent composition B: Use of hydrophobic acrylic binder + urethane binder>
Inorganic colloidal sol 1 (Snowtex ZL) 3.0
Inorganic colloidal sol 2 (Snowtex 20L) 3.0
Thermoplastic resin (GD88: hydrophobic acrylic binder resin) 3.2
Thermoplastic resin (WS-4000: Urethane binder resin) 0.8
Crosslinking aid (EB10) 0.1
Cross-linking agent (EA55) 0.2
Dispersion medium (water / IPA = 6/4) 90

WS-4000: Anionic polycarbonate polyurethane emulsion manufactured by Takeda Pharmaceutical Co., Ltd.

<Anti-fogging agent composition C: Use of hydrophilic acrylic binder>
Alcohol-dispersed colloidal silica (methanol silica) 5
Thermoplastic resin (Saftomer ST6400: hydrophilic acrylic binder resin) 5
Cross-linking agent (3-mercaptopropylmethyldimethoxysilane) 0.3
Surfactant (polyoxyethylene lauryl ether) 1
Dispersion medium (methanol) 80
(Note) The amount of inorganic colloidal sol is indicated by the amount of inorganic particles, and the amount of thermoplastic resin is indicated by the solid content of the polymer.
Methanol silica: Silica sol saftomer ST6400 manufactured by Nissan Chemical Industries, Ltd. Hydrophilic acrylic resin manufactured by Mitsubishi Chemical Corporation

The binder resin composition (not containing inorganic fine particles) for the lower layer coating film was blended as follows.
<Binder resin composition A>
Thermoplastic resin (GD88) 27.2
Cross-linking agent (NK Faster C60) 0.5
Dispersion medium (water) 72.3
NK Faster C60: Shin-Nakamura Chemical Co., Ltd.

<Binder resin composition B>
Thermoplastic resin (A-612) 31
Dispersion medium (water) 69
A-612: Enomoto Kasei Co., Ltd.

As a comparative example, a coating liquid (inorganic colloid solution type) for forming a lower layer coating film not containing a synthetic resin was prepared with the following formulation.
<Inorganic colloid solution type 1: no binder resin added>
1) 99% by weight of ion-exchanged water and 1% by weight of an inorganic layered compound (synthetic smectite: “SWF” manufactured by Coop Chemical Co., Ltd.) are mixed and stirred to obtain a synthetic smectite aqueous dispersion.
2) Ion-exchanged water 79.584% by weight, synthetic smectite aqueous dispersion 9.000% by weight, colloidal alumina aqueous dispersion (“Alumina Sol 520” manufactured by Nissan Chemical Industries, Ltd.) 9.000% by weight, colloidal silica water Dispersion liquid (“Snowtex 20” manufactured by Nissan Chemical Industries, Ltd.) 2.400% by weight, sodium caprylate (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) 0.02% by weight, sodium p-toluenesulfonate (Tokyo Chemical Industry) Made by Co., Ltd.) 0.002% by weight was mixed and stirred to obtain an inorganic colloid solution 1.

<Inorganic colloid solution type 2: no binder resin added>
The inorganic colloidal solution type 1 synthetic smectite was “SWN” manufactured by Co-op Chemical Co., Ltd., and used as the inorganic colloidal solution 2.

(3) Formation of lower layer coating film The coating liquid composition was applied to the surface of the base film surface-treated in (2) using # 8 or # 5 bar coater. The coated film was held in an oven at 80 ° C. for 1 minute to volatilize the liquid dispersion medium to form a lower layer coating film, and then the thickness of each coating film obtained was confirmed.

(4) Preparation of anti-fogging agent composition for upper coating film Anti-fogging described in each table by blending a solution in which various inorganic fine particles of the main components shown below are dispersed in water or a mixed solvent of water and IPA An agent composition was obtained.
Colloidal silica A: Snowtex ZL (Nissan Chemical Co., Ltd.)
Colloidal silica B: Snowtex 20 (Nissan Chemical Co., Ltd.)
Colloidal silica C: Snowtex 20L (Nissan Chemical Co., Ltd.)

(5) Formation of upper layer coating film The above-mentioned various antifogging agent compositions are applied to the surface of the base film coated with the antifogging agent composition prepared in (4) in (3) using a # 3 bar coater. Each was applied. The applied film was kept in an oven at 80 ° C. for 1 minute to volatilize the liquid dispersion medium to form an upper layer coating film.

  The following physical properties were measured for each sample created by the above method, but the same resin, additive, combination other than the coating film, or film thickness different from this time, unless the gist is changed. The effect is obtained. The following tests were conducted for each sample used this time. Each measuring method in an Example and a comparative example is shown below.

(Evaluation methods)
Transparency The straight-line light transmittance at a wavelength of 555 nm of the film after forming (coating) the upper layer coating film was measured with a spectrophotometer (manufactured by Hitachi, U3500 type), and the value was shown.

Haze value (HAZE)
The HAZE value (cloudiness value) of the film after forming (coating) the upper layer coating film was measured with a haze meter (manufactured by Tokyo Denshoku Co., Ltd .: TC-H3DP), and the value was shown.

Coating film adhesion In the film after forming (coating) the upper-layer coating film, the cellophane tape is adhered to the surface of the molded product where the coating film is formed, and the load applied when the cellophane tape is peeled off is the tensile test described in JIS-K6732. A T-peel strength was measured at a test speed of 500 mm / min and a temperature of 23 ° C. using a machine, and the numerical value was shown.

Coating appearance The appearance of the molded product was observed with the naked eye. The evaluation criteria are as follows.
◎… with good transparency compared to the base film coated with only the antifogging agent composition (no upper layer coating film) ○… with only the antifogging agent composition coated on the base film In comparison, the transparency is almost the same.
◯ ×: A film in which a decrease in transparency is slightly recognized as compared with a base film coated only with an antifogging agent composition.
Δ: A considerable decrease in transparency is observed as compared to a substrate film coated only with an antifogging agent composition.
X: The deterioration of the transparency is very severe compared to the case where only the antifogging agent composition is applied to the base film, and it is not practical.

Anti-fogging property under non-condensing conditions Observation conditions based on the criteria for determining the speed of anti-fogging on the basis of the time until water droplets begin to flow under non-condensing conditions. The surface on which the coating film is formed is arranged facing the inside of the water tank, the outside air temperature is kept at 12 ° C., the water temperature inside the water tank is kept at 22 ° C., and the speed of appearance of the antifogging property after a predetermined time is observed with the naked eye, The time until the water droplet started flowing was shown.
Also, the antifogging property was evaluated according to the following evaluation criteria depending on the time until water droplets started to flow.
◎ ... Time before water drops begin to flow is less than 60 minutes.
○ ... The time until the water droplet starts flowing is longer than 60 minutes and within 90 minutes.
XX: The time until the water droplet starts flowing is longer than 90 minutes and within 120.
Δ: Time until water droplets start to flow is longer than 120 minutes and within 150.
X: The time until the water droplet starts flowing is longer than 150 minutes.

Anti-blocking property In a thermostatic chamber maintained at 50 ° C., place the 10 cm square sample coating surfaces in contact with each other, and add 1 cc of water so that the water spreads evenly between the two sample coatings. Included. In this state, when the film after being left for 15 hours in a constant temperature room at 50 ° C. with a load of 150 kg per 100 cm ² is cut into 2.5 cm × 10 cm in a stacked state, and the two films are peeled in the longitudinal direction Was measured as a T-peel strength at a test speed of 500 mm / min and a temperature of 23 ° C. using a tensile tester described in JIS-K6732, and the numerical value was shown.

(Examples 1-5, Comparative Examples 1-2, Reference Example 1)
By the above formulation, a polyolefin three-layer film (substrate film) having a film thickness of 150 μm and a layer ratio of 1/3/1 is prepared, and an antifogging agent composition A or B (binder resin component: acrylic resin or acrylic) is formed thereon. After the application of the resin and urethane resin), an anti-fogging agent composition containing inorganic fine particles (colloidal silica) was applied to produce a film in which an upper layer coating film was formed (Examples 1 to 5). Moreover, the film which does not form an upper layer coating film as a comparative example was produced, and the commercially available polyolefin-type film for agriculture (Mitsubishi Chemical MKV Co., Ltd. product "Super solar mutex S") was prepared as a reference example. Evaluation of anti-fogging property under conditions where transparency, fog value, coating film adhesion, appearance, and dew condensation are difficult was carried out by the above-described methods. The results are shown in Tables 2 and 3. From these results, the polyolefin film according to the present invention has very high transparency, good coating film adhesion, and extremely high antifogging property as compared with a commercially available polyolefin film for agriculture. It turns out that it has.

(Examples 6 to 8)
By the above blending, a polyolefin three-layer film (base film) having a film thickness of 150 μm and a layer ratio of 1/3/1 was prepared, and antifogging agent composition A and binder resin compositions A and B were applied on the base film, respectively. After that, a film was formed by applying an antifogging agent composition containing inorganic fine particles to form an upper coating film. By the above methods, the evaluation of anti-fogging property was carried out under the conditions of transparency, haze value, coating film adhesion, appearance, conditions that hardly cause condensation and conditions that hardly cause condensation after a load test. The results are shown in Table 4. From this result, it can be seen that any of the films of Examples 6 to 8 has very high transparency, good coating film adhesion, and extremely high antifogging properties. Moreover, when the antifogging agent composition was applied to the lower layer coating film, better antifogging properties were exhibited even under conditions where condensation was difficult after the load test.

(Example 9, Comparative Examples 3 and 4)
A polyolefin-type three-layer film having a film thickness of 150 μm and a layer ratio of 1/3/1 was prepared by the above composition, and an antifogging agent composition A (Example 9) or an inorganic colloid solution (without a binder resin component) on the base film; comparison After applying Examples 3 and 4), a film in which an anti-fogging agent composition containing inorganic fine particles was applied to form an upper layer coating film was prepared. Evaluation of anti-fogging property under conditions where transparency, haze value, appearance, and dew condensation are difficult was carried out by the above-described methods. The results are shown in Table 5. From these results, it can be seen that the polyolefin film according to the present invention has very high transparency, and when the lower layer coating film does not have a binder resin component, it is clearly inferior in transparency and antifogging property.

(Examples 10 and 11, Comparative Example 5)
By the above formulation, a polyolefin three-layer film having a film thickness of 150 μm and a layer ratio of 1/3/1 was prepared, and after applying antifogging agent composition C (binder resin component: hydrophilic acrylic resin) to the base film, inorganic A film (Examples 10 and 11) on which an anti-fogging agent composition containing fine particles was applied to form an upper coating film and a film on which the anti-fogging agent composition was not applied (Comparative Example 5) were prepared. The coating film adhesion and anti-blocking properties were evaluated by the above methods. The results are shown in Table 6. From these results, it can be seen that the polyolefin film according to the present invention has a very high anti-blocking property.

(Examples 12 and 13, Comparative Example 6, Reference Example 2)
A film in which a commercially available PET film having a film thickness of 150 μm was used, an antifogging agent composition A was applied to a base film, and then an antifogging agent composition containing inorganic fine particles was applied to form an upper coating film (Example) 12 and 13) and a film (Comparative Example 6) to which the antifogging agent composition was not applied were prepared. Evaluation of anti-fogging property under conditions where transparency, fog value, coating film adhesion, appearance, and dew condensation are difficult was carried out by the above-described methods. The results are shown in Table 7. From these results, the PET film according to the present invention has very high transparency, good coating film adhesion, and a commercially available polyethylene terephthalate film for agriculture (“Sixlite” manufactured by Mitsubishi Chemical MKV Co., Ltd.). It can be seen that it has an extremely high antifogging property even compared with “clean mute”.

(Examples 14 to 17, Comparative Example 7)
After applying the antifogging agent composition A on the PO base film 1, an antifogging agent composition containing inorganic fine particles and a synthetic resin binder B at a predetermined ratio was applied to produce a film in which an upper coating film was formed. . Evaluation of anti-fogging property was performed by the above-described methods under the conditions of transparency, fog value, appearance, conditions that hardly cause condensation, and conditions that hardly cause condensation after a load test. The results are shown in Table 8.

  As is clear from the above results, on the surface of the base film that becomes the inside of the house when stretched according to the present invention, a lower layer coating film containing synthetic resin or synthetic resin and inorganic fine particles is formed, and the inorganic fine particles are the main component. Agricultural film characterized by forming an upper layer coating film has very good anti-fogging property and excellent anti-blocking performance via water, and is provided as an anti-fogging coating film. It has excellent performance (antifogging properties, blocking resistance, coating film adhesion, etc.) and is excellent as an antifogging coating film for agricultural films (Examples 1 to 13).

  Further, by adding the ethylene-cyclic aminovinyl compound according to the present invention to the side in contact with the antifogging coating film, the adhesion of the antifogging coating film is not impaired as described in JP-A-2001-161180. Can be further improved, which is preferable.

  In addition, when the synthetic resin binder is lacking in the lower layer coating film, the antifogging property is inferior due to the influence of the inorganic viscosity adjusting agent and the charge adjusting agent necessary for ensuring the film forming property, and the binder resin is used. Compared with the case, it is inferior in transparency and has a problem in practical use. (Comparative Examples 3 and 4).

  In addition, when there is no upper layer coating film containing inorganic fine particles as a main component, the coating film adhesion can be ensured, but the antifogging property is inferior compared with the antifogging coating film according to the present invention, and through water. It is easy to block and has practical problems. (Comparative Example 5)

  That is, when the constituent elements according to the present invention are lacking, it cannot be said that the performance to be provided as an agricultural film is provided in a balanced manner.

Claims (11)

An agricultural film comprising: a base film that includes a synthetic resin, and an upper film that includes inorganic fine particles as a main component, on the surface of a base film that becomes the inside of a house when stretched. The agricultural film according to claim 1, wherein the lower coating film further contains inorganic fine particles. The agricultural film according to claim 1, wherein the upper layer coating film is formed by applying an antifogging agent composition containing an inorganic colloid sol as a main component to a base film. The agricultural film according to claim 3, wherein the inorganic colloidal sol is colloidal silica and / or colloidal alumina. The agricultural film according to any one of claims 2 to 4, wherein the lower layer coating film is formed by applying an antifogging agent composition containing a synthetic resin and an inorganic colloid sol to a base film. The agricultural film according to claim 5, wherein the inorganic colloidal sol is colloidal silica and / or colloidal alumina. The agricultural film according to any one of claims 1 to 6, wherein the synthetic resin is an acrylic resin and / or a urethane resin. The agricultural film according to claim 1, wherein the base film is a polyolefin-based resin. The agricultural film according to claim 1, wherein the base film is a polyethylene terephthalate resin. The agricultural film according to claim 8, wherein the base film has at least one layer containing a copolymer of ethylene (A) and a cyclic aminovinyl compound (B) represented by the following formula (1).

(In the formula, R1 and R2 each independently represent a hydrogen atom or a methyl group, and R3 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) The agricultural film according to claim 10, wherein R1 and R2 in the formula (1) are each a hydrogen atom or a methyl group, and R3 is a hydrogen atom.