JP2010132926A - Aqueous anti-clouding coating agent and material improved in anti-clouding property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous anti-clouding coating agent providing a coating film exhibiting anti-clouding properties over the long period of time, and at the same time, transparency at low temperature and having excellent water resistance and alkali resistance. <P>SOLUTION: In the aqueous anti-clouding coating material, a polyolefin resin of a specific composition, a water-soluble polymer and a basic compound are contained in an aqueous medium, and the number-average particle diameter of the polyolefin resin is 0.2 μm or lower. Various anti-clouding materials are obtained when the aqueous anti-clouding coating agent is applied to the surface of a thermoplastic resin, metal, and glass. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an aqueous antifogging coating agent and a material having improved antifogging properties obtained by applying the same.

In general, when the surface of a material such as a plastic such as a film, glass, or metal falls below the dew point, water in the air condenses and fine water droplets adhere to the material surface. If the material used is transparent, it becomes cloudy and loses transparency. For example, mirror fogging, window glass fogging, agricultural film fogging, and the like.

  When fogging occurs in agricultural films used for house cultivation, the problem is that the transmission of sunlight is hindered, the effective rays necessary for growing crops are insufficient, and the temperature in the house does not rise. Produce. In addition, when water drops fall directly on crops, they prevent the growth of crops, such as preventing mating and causing illness.

  As a method for improving the antifogging property of the film, there is known a method of adding a surfactant having a fatty acid ester such as sorbitan or glycerin as a representative example (for example, Patent Documents 1 to 5). However, there is a problem that the surfactant bleeds out to the surface with the passage of time and the antifogging property is lowered, so that it cannot be used for a long time.

On the other hand, it is known that long-term antifogging properties are improved by using inorganic colloids such as silica sol and alumina sol (see, for example, Patent Documents 4 to 8).
On the other hand, in order to prevent fogging of the surface of glass or metal, an antifogging coating agent is applied to the surface of such a material. In this case, physical properties such as minimum film forming properties, adhesion to materials, and water resistance required as a coating agent depend on the properties of the binder resin used for the coating agent. The binder resin conventionally used as an antifogging coating agent contains a large amount of hydroxyl groups and carboxyl groups in the molecule, so the water resistance and alkali resistance of the coating film are poor, and the adhesion to the substrate is poor. There were problems such as inadequate.

  Furthermore, in consideration of environmental protection, resource saving, regulations on dangerous goods by the Fire Service Law, and workplace environment improvement, the dispersion medium of the coating agent is preferably water-based.

Japanese Patent Publication No.49-32668 Japanese Patent Publication No. 50-11348 Japanese Patent Publication No.53-37075 Japanese Patent Laid-Open No. 57-119974 JP 59-15473 A JP-A-55-99987 JP-A 64-246984 JP-A-8-188682

  The present inventors provide an aqueous anti-fogging coating agent that can form an anti-fogging property over a long period of time, and at the same time, can form a coating film excellent in water resistance and alkali resistance at a low temperature. Is.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention include a specific composition of a polyolefin resin having a small number average particle size and neutralized with a basic compound and a water-soluble polymer in a specific ratio. Thus, the present inventors have found that the above problems can be solved, and have reached the present invention.

That is, the gist of the present invention is as follows.
First, the following polyolefin resin (A), an aqueous polymer (B), and a basic compound, wherein the number average particle diameter of the polyolefin resin is 0.2 μm or less, an aqueous antifogging characterized by A coating agent,
Polyolefin resin (A):
(A1) unsaturated carboxylic acid or anhydride thereof,
(A2) ethylene hydrocarbon,
(A3) A copolymer composed of at least one compound represented by any of the following formulas (I) to (IV), wherein the mass ratio of each of the constituent components (A1) to (A3) is as follows: Polyolefin resin satisfying the formulas (1) and (2).
0.01 ≦ (A1) / {(A1) + (A2) + (A3)} × 100 <5 (1)
(A2) / (A3) = 55 / 45-99 / 1 (2)
The second is an antifogging material in which a coating film obtained from the coating agent is formed on the surface of a thermoplastic resin molded body, metal or glass.

  Adhesiveness to various substrates by containing a specific amount of polyolefin resin with a specific composition having a number average particle size of 0.2 μm or less and neutralized with a basic compound, and a water-soluble polymer The resulting coating film exhibits excellent water resistance, alkali resistance, and antifogging properties over a long period of time.

  Hereinafter, the present invention will be described in detail.

  The anti-fogging coating agent of the present invention is obtained by dispersing a polyolefin resin having a specific composition shown below, a water-soluble polymer and a basic compound in an aqueous medium.

  In the polyolefin resin used in the present invention, the unsaturated carboxylic acid or its anhydride (A1) component is 0.01% by mass or more and 5% by mass with respect to the entire resin [(A1) + (A2) + (A3)]. %, More preferably 0.1% by weight or more and less than 5% by weight, more preferably 0.5% by weight or more and less than 5% by weight. Most preferred. When the content of the component (A1) is less than 0.01% by mass, it becomes difficult to make the resin aqueous (liquefaction) and it is difficult to obtain a good aqueous dispersion. On the other hand, when the content of the unsaturated carboxylic acid or its anhydride is 5% by mass or more, it is easy to make it water-based, but the physical properties such as water resistance and alkali resistance of the coating film and adhesion to a film with low polarity May decrease.

  The unsaturated carboxylic acid or anhydride thereof that can be used as the component (A1) of the polyolefin resin is a compound having at least one carboxyl group or acid anhydride group in the molecule (in the monomer unit), specifically Examples thereof include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, and the like, as well as unsaturated dicarboxylic acid half esters and half amides. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and acrylic acid and maleic anhydride are particularly preferable. Moreover, the unsaturated carboxylic acid should just be copolymerized in polyolefin resin, The form is not limited, For example, random copolymerization, block copolymerization, graft copolymerization etc. are mentioned.

  In the polyolefin resin used in the present invention, the component (A3) represented by any of the following formulas (I) to (IV) is necessary as a constituent component, and hydrophilicity is imparted to the polyolefin resin by this component. Even if the component (A1) is less than 5% by mass, it can be made aqueous without the addition of a non-volatile aqueous additive. The mass ratio (A2) / (A3) between the ethylene-based hydrocarbon (A2) component and the (A3) component needs to be in the range of 55/45 to 99/1, and 60/40 to 98/2. Preferably 65/35 to 97/3, more preferably 70/30 to 97/3, and particularly preferably 75/25 to 97/3. When the ratio of the component (A3) to [(A2) + (A3)] is less than 1% by mass, it becomes difficult to make the polyolefin resin water-based and it is difficult to obtain a good aqueous dispersion. On the other hand, when the content ratio of the compound (A3) exceeds 45% by mass, properties as a polyolefin resin due to the component (A2) are lost, and performance such as water resistance is deteriorated.

  In the present invention, the ethylene hydrocarbon (A2) component constituting the polyolefin resin includes C2-C6 alkenes such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, Mixtures of these can also be used. Among these, alkenes having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene are more preferable, and ethylene is particularly preferable.

  In the present invention, as the component (A3) represented by any one of the above formulas (I) to (IV) constituting the polyolefin resin, for example, methyl (meth) acrylate represented by the formula (I), (meta ) (Meth) acrylic acid esters such as ethyl acrylate and butyl (meth) acrylate, maleic acid esters such as dimethyl maleate, diethyl maleate and dibutyl maleate represented by the formula (II): ) (Meth) acrylic amides represented by formula (IV), alkyl vinyl ethers represented by formula (IV) such as methyl vinyl ether and ethyl vinyl ether, vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate Vinyl esters obtained by saponifying vinyl esters with basic compounds, etc. Alcohols, and the like, can also be a mixture thereof. Among these, (meth) acrylic acid esters represented by the formula (I) are more preferable, and methyl (meth) acrylate or ethyl (meth) acrylate is particularly preferable.

  The polyolefin resin used in the present invention is most preferably a terpolymer comprising ethylene, methyl acrylate or ethyl acrylate, and maleic anhydride. Here, the acrylic ester unit may be converted into an acrylic acid unit by hydrolyzing a small part of the ester bond when the resin is made into an aqueous solution described later. It suffices if the ratio of each constituent component taking into account the change is within a specified range.

  In addition, unsaturated carboxylic anhydride units such as maleic anhydride units constituting the polyolefin resin in the present invention form an acid anhydride structure in which the adjacent carboxyl group is dehydrated and cyclized in the dry state of the resin. In an aqueous medium containing a basic compound, a part or all of the ring is opened to facilitate the structure of a carboxylic acid or a salt thereof.

  In the present invention, when the amount is defined based on the amount of carboxyl group of the resin, the calculation is performed assuming that all acid anhydride groups in the resin are ring-opened to form carboxyl groups.

  The polyolefin resin used in the present invention may be copolymerized with a small amount of other monomers. Examples thereof include dienes, (meth) acrylonitrile, halogenated vinyls, halogenated vinylidenes, carbon monoxide, and sulfur dioxide.

  The molecular weight of the polyolefin resin used in the present invention is not particularly limited, but the melt flow rate at 190 ° C. and 2160 g load, which is a measure of molecular weight, is preferably 0.1 to 500 g / 10 minutes, more preferably 0.5 to 400 g. / 10 minutes, more preferably 1 to 300 g / 10 minutes, most preferably 1 to 250 g / 10 minutes. If the melt flow rate of the polyolefin resin is less than 0.1 g / 10 min, it becomes difficult to make the resin water-based and it is difficult to obtain a good aqueous dispersion. On the other hand, when the melt flow rate of the polyolefin resin exceeds 500 g / 10 min, the coating film obtained from the aqueous dispersion becomes hard and brittle, and the mechanical strength and the adhesion to the substrate are lowered.

  The method for synthesizing the polyolefin resin used in the present invention is not particularly limited. Generally, it is obtained by high-pressure radical copolymerization of a monomer constituting the polyolefin resin in the presence of a radical generator. In addition, the unsaturated carboxylic acid or its anhydride may be graft copolymerized (grafted modification).

  Further, the number average particle diameter (hereinafter referred to as mn) of the polyolefin resin particles dispersed in the aqueous dispersion of the present invention is from the viewpoint of the storage stability of the aqueous dispersion and the film-forming property at a low temperature. It needs to be 2 μm or less, and more preferably 0.1 μm or less. Further, the weight average particle diameter (hereinafter, mw) is preferably 0.3 μm or less, and more preferably 0.2 μm or less. The degree of particle dispersion (mw / mn) is preferably 1 to 3, more preferably 1 to 2.5, and particularly preferably 1 to 2 from the viewpoint of storage stability of the aqueous dispersion and low-temperature film-forming properties. The above particle diameter range can be achieved by using a basic compound in dispersing the polyolefin resin in an aqueous medium. At this time, it is not necessary to use a non-volatile aqueous additive such as an emulsifier or a compound having a protective colloid action.

  Examples of the water-soluble polymer (B) include polyvinyl alcohol, modified polyvinyl alcohol such as carboxyl group-modified polyvinyl alcohol, polyalkylene oxide, polyethyleneimine, polyallylamine, cellulose compounds such as carboxymethylcellulose and hydroxyethylcellulose, starch, and modified starch. , Polysaccharides such as guar gum and carrageenan, alginate, polyvinyl pyrrolidone, polyoxyethylene, polyvinyl methyl ether, polyoxazoline, poly (meth) acrylic acid and its salt, acrylic acid-maleic anhydride copolymer and its salt, styrene -(Meth) acrylic acid copolymer and salt thereof, ethylene- (meth) acrylic acid copolymer and salt thereof, methyl vinyl ether-maleic anhydride alternating copolymer and Salt, isobutylene-maleic anhydride alternating copolymer and salt thereof, polyitaconic acid and salt thereof, polymaleic acid and salt thereof, water-soluble acrylic copolymer having amino group such as polyacrylamide, dextrin, gelatin and gum arabic , Casein, collagen and the like. You may use these in mixture of 2 or more types. Among these, polyvinyl alcohol, polyvinyl pyrrolidone, and polyoxyethylene are preferable from the viewpoint of mixing stability with the aqueous polyolefin resin dispersion, and polyvinyl alcohol and ethylene-vinyl alcohol copolymer are particularly preferable. The saponification degree of polyvinyl alcohol is preferably 80 to 100%, and the polymerization degree is preferably 200 to 2000 because it is easy to handle as an aqueous solution. Furthermore, the solvent resistance of the coating film is remarkably improved by adding a predetermined amount of polyvinyl alcohol.

  The addition amount of the water-soluble polymer (B) needs to be such that the solid content mass ratio (A) / (B) between the polyolefin resins (A) and (B) is 95/5 to 20/80, and is water resistant. From the viewpoints of alkali resistance, antifogging properties, and adhesion to a substrate, 95/5 to 30/70 is preferable, 90/10 to 40/60 is more preferable, and 90/10 to 50/50 is particularly preferable. When the addition amount of the water-soluble polymer is less than 5% by mass, the antifogging effect is small, and when it exceeds 80% by mass, the water resistance, alkali resistance and adhesion to the substrate are lowered. Furthermore, when polyvinyl alcohol is used as the water-soluble polymer (B), the addition amount is preferably 90/10 to 20/80, more preferably 85/15 to 30/70, from the viewpoint of the durability of the coating film. In view of adhesion to the substrate, 85/15 to 50/50 is particularly preferable.

  Furthermore, the anti-fogging coating agent of the present invention may contain an inorganic colloid (C). Examples of the inorganic colloid (C) include inorganic aqueous colloidal particles such as silica, alumina, smectite such as saponite and hectorite, water-insoluble lithium silicate, alkali metal silicate, tin oxide, and titanium oxide in water or an aqueous medium. A dispersed aqueous sol may be mentioned. Among these, colloidal silica is preferable from the viewpoint of mixing stability with the aqueous polyolefin resin dispersion and antifogging properties. The number average particle diameter is preferably 0.001 to 10 μm, more preferably 0.005 to 1 μm, particularly preferably 0.01 to 0.5 μm in consideration of transparency. The inorganic colloid (C) may be used as a mixture of two or more.

  The solid content mass ratio (A) / (C) between the polyolefin resin (A) and the inorganic colloid (C) is preferably 80/20 to 20/80, and is antifogging and adhesion to the substrate. From this point, 75/25 to 30/70 is more preferable, and 70/30 to 40/60 is particularly preferable. When the added amount of the inorganic colloid is less than 20% by mass, the antifogging effect is small, and when it exceeds 80% by mass, the adhesion to the substrate is lowered.

  In the case of adding the inorganic colloid (C), it is preferable to further perform jet pulverization treatment from the viewpoint of improving the transparency of the coating film as necessary. Jet pulverization here refers to jetting fluid from pores such as nozzles and slits under high pressure, causing inorganic particles to collide with each other and colliding plates with mechanical energy, etc. Furthermore, as a specific example of an apparatus for that purpose, A. P. V. Examples include a homogenizer manufactured by GAULIN, and a microfluidizer M-110E / H manufactured by Mizuho Industries.

  Further, the water-soluble polymer (B) and the inorganic colloid (C) may be mixed and used. In that case, the amount of (B) and (C) added to the polyolefin resin is as described above. It may be in a range satisfying the relationship with the polyolefin resin (A).

  Various additives can be added to the aqueous antifogging coating agent of the present invention. Examples of such additives include surface active antifogging agents, antioxidants, plasticizers, leveling agents, antifoaming agents, anti-waxing agents, ultraviolet absorbers, colorants or dyes, crosslinking agents, and polyolefin resins (A). An aqueous resin dispersion of Two or more of the above-described additives may be used in combination.

  As the crosslinking agent, for example, a crosslinking agent having self-crosslinking property, a compound having a plurality of functional groups that react with a carboxyl group in the molecule, a metal having a multivalent coordination site, a metal complex, or the like can be used. Among these, an isocyanate compound, a melamine compound, a urea compound, an epoxy compound, a carbodiimide compound, an oxazoline group-containing compound, a zirconium salt compound, a silane coupling agent, and the like can be given. Various coating film performances, such as water resistance, can further be improved by adding a crosslinking agent. The addition amount of a crosslinking agent is 0.01-100 mass parts with respect to 100 mass parts of polyolefin resin (A) in an aqueous antifogging coating agent, Preferably 0.1-60 mass parts can be added. When the addition amount of the crosslinking agent is less than 0.01 parts by mass, the degree of improvement in coating film performance such as water resistance is small, and when it exceeds 100 parts by mass, the crosslinking density of the coating film increases, Performance such as workability will deteriorate.

  In order to impart initial antifogging property, a surfactant can be added, which is an effective means. For example, a fatty acid ester of a polyhydric alcohol such as glycerin, diglycerin or sorbitan is added in an amount of 0.1 to 20 parts by mass, preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the polyolefin resin solid content. Is good.

  An aqueous resin dispersion other than the polyolefin resin (A) may be added to the aqueous antifogging coating agent of the present invention, and the type thereof is not particularly limited. For example, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, styrene-maleic acid resin, styrene-butadiene resin, butadiene resin, acrylonitrile-butadiene resin, poly (meth) acrylonitrile resin, chlorination Examples thereof include aqueous dispersions such as polyethylene resins, chlorinated polypropylene resins, polyester resins, modified nylon resins, urethane resins, phenol resins, silicone resins, and epoxy resins. You may use these in mixture of 2 or more types.

  The solid content in the aqueous antifogging coating agent of the present invention can be appropriately selected depending on the film forming conditions, the thickness and performance of the target resin coating film, and is not particularly limited. It is preferably 1 to 60% by mass, more preferably 3 to 55% by mass, further preferably 5 to 50% by mass, and particularly preferably 10 to 45% by mass in terms of maintaining an appropriate amount and exhibiting good coating film forming ability. preferable.

  The aqueous antifogging coating agent of the present invention needs to contain a basic compound. This is to neutralize a part of the carboxyl groups in the polyolefin resin and prevent aggregation between the polyolefin resin fine particles by the electric repulsive force between the carboxyl anions generated by the neutralization.

  The basic compound to be added is not particularly limited as long as it can neutralize the carboxyl group, and ammonia or an organic amine compound is preferable from the viewpoint of ease of making the polyolefin resin aqueous. The content of the basic compound is preferably 0.5 to 3.0-fold equivalent mole, more preferably 0.5 to 2.0-fold equivalent mole based on the number of moles of carboxyl groups in the polyolefin resin. When the addition amount of the basic compound is less than 0.5 times the equivalent mole, it becomes difficult to make the resin aqueous, or the stability of the polyolefin resin fine particles deteriorates. When the addition amount of the basic compound is less than 3.0 times the equivalent mole, the drying time may be prolonged or the stability of the polyolefin resin fine particles may be deteriorated.

  Specific examples of the organic amine compound include triethylamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, and 3-ethoxypropylamine. , 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N- Long chain alkylamines such as ethylmorpholine and octylamine can be exemplified.

  The aqueous antifogging coating agent of the present invention may contain an organic solvent. In this case, it is preferable to use an organic solvent having a solubility in water at 20 ° C. of 5 g / L or more, preferably 10 g / L or more, and the amount is preferably 40% by mass or less in the aqueous medium. 1 to 40% by mass, more preferably 2 to 35% by mass, and particularly preferably 3 to 30% by mass. When the amount of the organic solvent exceeds 40% by mass, it cannot be regarded as an aqueous medium substantially and does not deviate from one of the objects of the present invention (environmental protection). The stability of the may decrease.

  In addition, in order to make the particle diameter of polyolefin resin into 0.2 micrometer or less of this invention, when making this resin aqueous, it is preferable to use an organic solvent. In this case, the amount of the organic solvent used for the aqueous treatment can be reduced by a solvent removal process called “stripping” and can be adjusted to an arbitrary final concentration.

  Specific examples of the organic solvent used in the present invention include methanol, ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol. Monobutyl ether is preferable, and isopropanol is particularly preferable from the viewpoint of low temperature drying property.

  As a method for preparing the antifogging coating agent of the present invention, it is preferable to first prepare an aqueous dispersion of a polyolefin resin, and then mix an aqueous solution of an inorganic colloid or a water-soluble polymer with stirring.

  The anti-fogging coating agent of the present invention not only has excellent anti-fogging properties but also can form a highly transparent coating film at room temperature, and the haze of the coated film measured by the method described below 10.0% )

  The anti-fogging coating agent of the present invention can be adhered to various substrates to form an anti-fogging coating on the substrate surface. Suitable materials for the substrate include resin, glass, metal and the like. Although these are not particularly limited in shape, examples of the resin include various molded products, fibers, films, and the like. Specific applications of the film include agricultural films and food packaging films. As an agricultural film, a polyolefin resin film is preferable among the following base materials. Further, the glass material can be used for window glass and mirrors, and the metal material can be used for various plated steel sheets.

  Regardless of the thermosetting resin or thermoplastic resin used as the base material, for example, olefin resin, polyester resin, polyamide resin, phenol resin, epoxy resin, urea resin, melamine resin, polyimide resin, polycarbonate resin, polyarylate Examples thereof include resins, polyvinyl chloride resins, and polyvinylidene chloride resins. These may be used as a mixture.

  Examples of the polyolefin resin include polypropylene, low density polyethylene, medium density polyethylene, high density polyethylene, a copolymer of ethylene and an α-olefin having 3 or more carbon atoms, and ethylene having a vinyl acetate content of, for example, 20% by mass or less. -Vinyl acetate copolymer, ethylene having a (meth) acrylic acid ester content of, for example, 20% by mass or less-(Meth) acrylic acid ester copolymer, ethylene having an unsaturated carboxylic acid content, for example, of 20% by mass or less Examples thereof include unsaturated carboxylic acid copolymers, ionomer resins, and mixtures thereof.

  Polyester resins include polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polybutylene succinate, polyethylene succinate, polylactic acid, polyglycolic acid, poly ( ε-caprolactone), poly (δ-valerolactone), poly (3-hydroxycaproic acid), poly (3-hydroxybutyric acid), poly (3-hydroxyvaleric acid) and the like. May be.

  Examples of the polyamide resin include nylon 6, nylon 66, nylon 46, nylon 610, nylon 612, nylon 11, nylon 12, nylon MXD6, nylon 6T, nylon 6I, and the like, and these mixed polyamides and copolymers may be used.

  The substrate may be a laminate of the above resins (particularly, a laminate film in the case of a film). The substrate surface may be subjected to corona treatment or ozone treatment, or may be coated with an anchor coating agent. These surface treatments are particularly effective when the film is used as a substrate. Moreover, when setting it as a film, an unstretched film or a stretched film may be sufficient, and a manufacturing method is not specifically limited. Although thickness is not specifically limited, Usually, what is necessary is just 1-500 micrometers.

  Since the aqueous anti-fogging coating agent of the present invention is excellent in film forming ability, known film forming methods such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray Uniform resin by coating on the surface of various substrates uniformly by coating, dip coating, brushing, etc., and setting it near room temperature as required, followed by heat treatment for drying or drying and baking The coating film can be formed in close contact with various substrate surfaces. As a heating device at this time, a normal hot air circulation type oven, an infrared heater, or the like may be used. The heating temperature and heating time are not particularly limited.

  In addition, the thickness of the coating film formed using the anti-fogging coating agent of the present invention is appropriately selected depending on the application, but is preferably 0.05 to 30 μm, more preferably 0.1 to 20 μm. 0.2 to 15 μm is more preferable, and 0.3 to 10 μm is particularly preferable. If the film is formed so that the coating thickness is within the above range, a resin coating having excellent uniformity can be obtained.

  In addition, in order to adjust the coating thickness, in addition to appropriately selecting the equipment used for coating and its usage conditions, an anti-fogging coating agent with a concentration suitable for the desired resin coating thickness is used. It is preferable to do. The concentration at this time can be adjusted by the charged composition at the time of preparation. The antifogging coating agent once prepared may be adjusted by appropriately diluting or concentrating.

  The antifogging material to which the coating agent of the present invention is applied is used in a place with a lot of moisture or a place where condensation easily occurs, thereby reducing condensation on the surface of the coating film and improving antifogging properties. For example, it is suitable for use in mirrors and window glass around water, mirrors and glass in bathrooms, window glass in contact with the outside air, automobile window glass, building materials, agricultural films, and the like.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
Various characteristics were measured or evaluated by the following methods.

(1) Structure of polyolefin resin ¹ H-NMR analysis (manufactured by Varian, 300 MHz) was performed at 120 ° C. in orthodichlorobenzene (d ₄ ).

(2) Residual Amount of Ester Group after Aqueous Treatment After the aqueous aqueous polyolefin dispersion was dried at 150 ° C., ¹ H-NMR analysis (Varian Inc.) at 120 ° C. in orthodichlorobenzene (d ₄ ). Manufactured, 300 MHz), and the ester group residual ratio (%) was determined with the ester group amount of the acrylate ester before being made water-based as 100.

(3) Solid content concentration of polyolefin resin aqueous dispersion An appropriate amount of the polyolefin dispersion was weighed and heated at 150 ° C. until the mass of the residue (solid content) reached a constant weight to obtain the polyolefin resin solid content concentration.

(4) Viscosity of aqueous polyolefin resin dispersion The rotational viscosity of the aqueous dispersion at a temperature of 20 ° C was measured using a DVL-BII type digital viscometer (B type viscometer) manufactured by Tokimec.

(5) Average particle diameter of polyolefin resin particles The number average particle diameter (mn) and the weight average particle diameter (mw) were calculated | required using the Nikkiso Co., Ltd. make Microtrack particle size distribution analyzer UPA150 (MODEL No. 9340).

(6) Content of organic solvent in aqueous polyolefin resin dispersion Gas chromatograph GC-8A manufactured by Shimadzu Corporation [using FID detector, carrier gas: nitrogen, column packing material (manufactured by GL Sciences): PEG-HT (5 %)-Uniport HP (60/80 mesh), column size: diameter 3 mm × 3 m, sample charging temperature (injection temperature): 150 ° C., column temperature: 60 ° C., internal standard substance: n-butanol] A body or an aqueous dispersion diluted with water was directly put into the apparatus, and the content of the organic solvent was determined. The detection limit was 0.01% by mass.

(7) Water resistance of coating film An anti-fogging coating agent is coated on a 40 μm-thick ethylene / vinyl acetate copolymer film with a Mayer bar so that the coating thickness after drying is 1 μm, and dried at 70 ° C. for 1 minute. did. The coated film thus prepared was immersed in warm water at 40 ° C. for 3 minutes, and then the presence or absence of dissolution or peeling of the coating layer was visually evaluated.
○: No change in appearance.
X: A coating film melt | dissolves or peels.

(8) Alkali resistance of coating film An anti-fogging coating agent is coated on a 40 μm-thick ethylene / vinyl acetate copolymer film with a Mayer bar so that the coating thickness after drying becomes 1 μm, and dried at 70 ° C. for 1 minute. did. A NaOH aqueous solution adjusted to pH 12.0 at 20 ° C. was heated to 45 ° C. and stirred, and the coated film was immersed in this solution for 3 minutes. Then, it washed with water and evaluated the state of the coating film visually.
○: No change in appearance.
X: A coating film melt | dissolves or peels.

(9) Solvent resistance of coating film An anti-fogging coating agent is coated on a 40 μm-thick ethylene / vinyl acetate copolymer film with a Mayer bar so that the coating film thickness after drying becomes 1 μm, and at 70 ° C. for 1 minute. Dried. The surface of the coating film was rubbed several times with a cloth containing various organic solvents, and the state of the coating film surface was visually evaluated. As the organic solvent, isopropanol (reagent special grade), toluene (reagent special grade), and methylene chloride (reagent special grade) were used.
○: No change in appearance.
(Triangle | delta): A coating film becomes cloudy.
X: A coating film melt | dissolves or peels.

(10) Haze (cloudiness value)
According to JIS K7105, “Haze (%)” was measured using NDH2000 “turbidity, haze meter” manufactured by Nippon Denshoku Industries Co., Ltd. Using a 2.8% haze PET film (Embret PET12 manufactured by Unitika, thickness 12 μm) as a base material, a Meyer bar was used so that the coating thickness after drying the coating agent at 25 ° C. was 2 μm. After coating, the film was allowed to stand for 3 days in an atmosphere at 25 ° C. and dried to produce a coated film. Thus, the haze of the whole coat film produced was measured.

(11) Adhesiveness of coating film Anti-fogging coating agent is dried on 40 μm thick ethylene / vinyl acetate copolymer film, 5 mm thick glass plate, 0.8 mm thick hot dip galvanized steel sheet (manufactured by Nippon Test Panel Osaka Co., Ltd.) It was coated with a Mayer bar so that the subsequent coating thickness was 2 μm. When the substrate was a film, it was dried at 70 ° C. for 1 minute, and when it was any other substrate, it was dried at 120 ° C. for 1 minute. After standing at room temperature for 24 hours, an adhesion test was performed by the method of JIS K5400 8.5.2. The coat layer was cut to create 1 mm × 1 mm × 100 grid sections, which were peeled off with an adhesive tape, and evaluated by the number of remaining 100 grid sections without peeling. “N / 100” indicates that n of the 100 grids remain without being peeled off, and “100/100” indicates that they are not peeled off at all and have the best adhesion.

(12) Anti-fogging property of coating film An anti-fogging coating agent is coated on a 40 μm-thick ethylene / vinyl acetate copolymer film with a Mayer bar so that the coating thickness after drying becomes 2 μm, and at 70 ° C. for 1 minute. Dried. The mouth of a 200 ml beaker containing 100 ml of 40 ° C. warm water was covered with a coat film and left in a 40 ° C. atmosphere for 24 hours, and then the adhesion of water droplets on the coat surface was visually observed.
○: Water uniformly adheres to the surface of the coat surface, and no cloudiness is observed.
Δ: Partial or slight cloudiness was observed.
X: Water droplets adhered, and significant clouding was observed.

(13) Long-term anti-fogging property of coating film An anti-fogging coating agent is coated on a 40 μm-thick ethylene / vinyl acetate copolymer film with a Mayer bar so that the coating film thickness after drying becomes 2 μm. Dried for minutes. The coated film was immersed in water at 20 ° C. for 1 week and then dried again at 70 ° C. for 1 minute. The mouth of a 200 ml beaker containing 100 ml of 40 ° C. warm water was covered with the coated film subjected to the above treatment, and left in a 40 ° C. atmosphere for 24 hours, and then the adhesion of water droplets on the coat surface was visually observed.
○: Water uniformly adheres to the surface of the coat surface, and no cloudiness is observed.
Δ: Partial or slight cloudiness was observed.
X: Water droplets adhered, and significant clouding was observed.

  Table 1 shows the composition of the resin used. In addition, melting | fusing point of resin described in Table 1 is a value measured by DSC (measuring device: DSC-7 manufactured by Perkin Elmer), and melt flow rate is a method described in JIS 6730 (190 ° C., 2160 g load) It is the value measured by.

(Production of aqueous polyolefin resin dispersion E-1)
Using a stirrer equipped with a 1 liter glass container that can be sealed with a heater, 60.0 g of polyolefin resin [Bondaine HX-8290 (A), manufactured by Sumitomo Chemical Co., Ltd.], 60.0 g of isopropanol (hereinafter, IPA), 4.5 g (1.8 times equivalent to the carboxyl group of maleic anhydride in the resin) of triethylamine (hereinafter TEA) and 175.5 g of distilled water were charged into a glass container, and the stirring blade was rotated. When stirring was performed at a speed of 300 rpm, no precipitation of resin particles was observed at the bottom of the container, confirming that it was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 140 ° C. and further stirred for 20 minutes. Then, after putting in a water bath and cooling to room temperature (about 25 ° C.) while stirring at a rotational speed of 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a milky white uniform polyolefin resin aqueous dispersion E-1 was obtained.

  Various characteristics of the aqueous dispersion are shown in Table 2. The number average particle diameter was 0.072 μm, and the distribution was one peak, and the polyolefin resin was dispersed in a good state in the aqueous medium. Furthermore, the pot life of this aqueous dispersion was 90 days or more. In addition, when the resin composition after water-ized was analyzed, the residual rate of ethyl acrylate was 100% and ester was not hydrolyzed.

  This ester group residual rate was 100% at room temperature for 90 days and remained unchanged after standing. The haze of the coated film coated with this aqueous dispersion by the method described above was 2.8%, and the transparency was good.

(Production of aqueous polyolefin resin dispersion E-2)
E-1 250 g and distilled water 40 g were charged into a 0.5 liter 2-neck round bottom flask, a mechanical stirrer and a Liebig condenser were installed, and the flask was heated in an oil bath to distill off the aqueous medium. When about 95 g of the aqueous medium was distilled off, heating was terminated and the mixture was cooled to room temperature. After cooling, the liquid component in the flask was subjected to pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave), and the solid content concentration of the filtrate was measured to find 25.8 mass. %Met. While stirring the filtrate, distilled water was added to adjust the solid content concentration to 25.0% by mass.

  Various characteristics of the aqueous dispersion are shown in Table 2. In addition, the content rate of the water-soluble organic solvent in this aqueous dispersion was 0.5 mass%.

(Production of aqueous polyolefin resin dispersion E-3)
Ethylene-acrylic acid copolymer resin [Primacol 5980I (I), acrylic acid 20% by mass copolymer, manufactured by Dow Chemical] was used as the polyolefin resin. Using a stirrer equipped with a hermetically sealed 1 liter glass container with a heater, 60.0 g of ethylene-acrylic acid copolymer resin [Primacol 5980I (I), manufactured by Dow Chemical Co., Ltd.], 16.8 g ( TEA of 1.0 times equivalent to the carboxyl group of acrylic acid in the resin) and 223.2 g of distilled water were charged into a glass container and stirred at a rotation speed of 300 rpm, Precipitation of the resin granular material was not recognized, and it was confirmed that it was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 100 ° C. and further stirred for 20 minutes. Then, after putting in a water bath and cooling to room temperature (about 25 ° C.) while stirring at a rotational speed of 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a slightly cloudy aqueous dispersion E-5 was obtained. At this time, almost no resin remained on the filter. Various characteristics of the aqueous dispersion are shown in Table 2.

Example 1
80% solid content mass ratio of polyolefin aqueous dispersion E-2 and polyvinyl alcohol (UF040G, degree of saponification 98.4%, degree of polymerization about 400, manufactured by Unitika Chemical, hereinafter abbreviated as “PVA”). An anti-fogging coating agent M-1 was prepared by mixing and stirring so as to be / 20.

Examples 2-5
Antifogging coating agents M-2 to M-5 were prepared in the same manner as in Example 1 except that the amount of PVA added was changed as shown in Table 3 using polyolefin aqueous dispersion E-1.

Example 6
An anti-fogging coating agent M-6 was prepared by mixing and stirring a polyolefin aqueous dispersion E-2, colloidal silica S—O, and a 10% aqueous solution of PVA such that the solid content mass ratio was as shown in Table 3.

  Table 3 summarizes the performance evaluation results of the coating films obtained from the coating agents of Examples 1 to 6.

Comparative Examples 1 and 2
Antifogging coating agents H-1 and H-2 were prepared in the same manner as in Example 1 except that the ratio of the polyolefin resin and PVA was changed as shown in Table 4.

Comparative Example 3
An antifogging coating agent H-3 was prepared in the same manner as in Example 1 except that the polyolefin aqueous dispersion E-3 having a large amount of unsaturated carboxylic acid was used.

  Table 4 summarizes the performance evaluation results of the coating films obtained from the coating agents of Comparative Examples 1 to 3.

  In Examples 1-6, the outstanding coating film which has water resistance, alkali resistance, solvent resistance, adhesiveness, transparency, and antifogging property was obtained. Among these, in Example 5, although it was inferior in water resistance and alkali resistance, it was in the level which is practically satisfactory if a use is chosen. Further, when both the inorganic colloid and the water-soluble polymer were contained as in Example 6, the effect of improving the solvent resistance was remarkable.

In contrast, the comparative example has the following problems. That is, in Comparative Example 1, since the amount of the water-soluble polymer deviated from the range of the present invention, the antifogging effect was insufficient. In Comparative Example 2, since the amount of the water-soluble polymer deviated from the range of the present invention, water resistance, alkali resistance and adhesion were insufficient, and long-term antifogging property was insufficient. Comparative Example 3 is an example in which the structure of the polyolefin resin is outside the scope of the present invention, and the copolymerization amount of the unsaturated carboxylic acid is high, but even when combined with a water-soluble polymer as in Comparative Example 3, it is antifogging. Was insufficient.

Claims (11)

The following polyolefin resin (A), aqueous polymer (B) and basic compound are contained in an aqueous medium, and the solid content mass ratio (A) / (B) between (A) and (B) is 95 / 5-5. An aqueous anti-fogging coating agent characterized by being 20/80 and having a polyolefin resin number-average particle size of 0.2 μm or less.
Polyolefin resin (A):
(A1) unsaturated carboxylic acid or anhydride thereof,
(A2) ethylene hydrocarbon,
(A3) A copolymer composed of at least one compound represented by any one of the following formulas (I) to (IV), wherein the mass ratio of each component (A1) to (A3) is Polyolefin resin satisfying the formulas (1) and (2).
0.01 ≦ (A1) / {(A1) + (A2) + (A3)} × 100 <5 (1)
(A2) / (A3) = 55 / 45-99 / 1 (2)
  An aqueous antifogging coating agent coats this aqueous antifogging coating agent on a film having a film thickness of 2 μm (after drying) at 25 ° C. at 25 ° C. at 25 ° C. 2. The aqueous antifogging coating agent according to claim 1, wherein the haze of the entire coated film obtained by drying is 10.0 (%) or less.   The aqueous anti-fogging coating agent according to claim 1 or 2, wherein the polyolefin resin (A) has a melt flow rate of 0.1 to 500 g / 10 min at 190 ° C and a load of 2160 g.   The polyolefin resin (A) is an ethylene-acrylic acid ester-maleic anhydride terpolymer or an ethylene-methacrylic acid ester-maleic anhydride terpolymer. An aqueous anti-fogging coating agent as described in 1.   5. The basic compound is an organic amine compound, and the content of the organic amine compound is 0.5 to 3.0 times equivalent mol to the number of moles of carboxyl groups in the polyolefin resin. The aqueous anti-fogging coating agent according to any one of the above.   An antifogging thermoplastic resin molded article in which a coating film comprising the aqueous antifogging coating agent according to any one of claims 1 to 5 is formed on the surface of a thermoplastic resin molded article.   An antifogging metal material in which a coating film comprising the aqueous antifogging coating agent according to any one of claims 1 to 5 is formed on a surface of a metal material.   An antifogging glass in which a coating film comprising the aqueous antifogging coating agent according to any one of claims 1 to 5 is formed on the surface of the glass.   The antifogging thermoplastic resin molded article according to claim 6, wherein the thickness of the coating film is 0.05 to 30 µm.   The antifogging metal material according to claim 7, wherein the thickness of the coating film is 0.05 to 30 µm. The antifogging glass according to claim 8, wherein the thickness of the coating film is 0.05 to 30 μm.