JP2008019284A - Tin oxide based ultrafine particle coating agent - Google Patents

Abstract

The present invention relates to a tin oxide that exhibits excellent coating properties even on a film or sheet that has not been subjected to a physical surface treatment such as corona discharge treatment without deteriorating other physical properties such as adhesion and printability. An ultrafine particle-containing coating agent is provided.
SOLUTION: The content of tin oxide ultrafine particles containing water dispersible polymer, tin oxide ultrafine particles, hydrophilic organic solvent, and water to make 100 parts by mass of water dispersible polymer is 100 to 10,000 parts by mass. And a solid content concentration of 0.1 to 8% by mass and a hydrophilic organic solvent content of 30% by mass or more, at a temperature of 20 ° C. and a shear rate of 20.40 s ^{− The} coating agent characterized by the viscosity in ¹ being 50-500 mPa * s.
[Selection figure] None

Description

  The present invention relates to a tin oxide-based ultrafine particle-containing coating agent that obtains a good coating film formation and a finished appearance without impairing adhesion and water resistance.

  Thermoplastic resin films and sheets are rarely used alone, and surface modification treatment is performed according to the application. For example, for use as a packaging for electronic materials or the like, antistatic performance is generally imparted to the surface. Examples of the antistatic treatment include a method of applying a tin oxide-based ultrafine particle-containing coating agent (Patent Documents 1 and 2).

  In general, a coating agent containing tin oxide-based fine particles is water-based, but the coating property is poor because the surface of the film or sheet is highly hydrophobic. Therefore, when a water-based coating agent is applied, a substrate having a surface that is subjected to dynamic surface treatment such as corona discharge treatment to make the surface hydrophilic and improve coatability is used (see Patent Documents 1 and 2). . Corona discharge treatment is a very effective method because it can modify the surface without damaging the properties of the substrate, but in addition to the cumbersome process of applying corona discharge treatment, depending on the substrate, There is a problem in that the effect of the corona discharge treatment gradually disappears and troubles such as coating properties are deteriorated.

  Other methods for improving coatability include a method of increasing the content of the organic solvent in the coating agent, a method of adding a surfactant, and a method of adding a thickener. However, in a system using tin oxide ultrafine particles that are dispersed and stabilized in water, if the solvent content is increased, agglomerates may be generated, and even if no agglomerates are generated, the solid content can be increased by increasing the solvent content. In addition to the decrease in the partial concentration, the coating agent may be excessively wetted and spread, so that an appropriate coating thickness cannot be obtained, resulting in uneven drying and uneven coating, and the appearance and surface state may deteriorate. In addition, when a surfactant is added, as described in Patent Document 1 (in the section of the embodiment of the invention), there is generally a problem that the adhesion of the coating film deteriorates and a problem that the surfactant bleeds out. Will occur. Similarly, when a thickener is added, there arises a problem that adhesion is deteriorated.

JP 2002-80775 A JP 2002-226775 A

  The present invention provides a tin oxide system that exhibits excellent coating properties even on films and sheets that have not been subjected to physical surface treatment such as corona discharge treatment without degrading performance such as adhesion and printability. An object is to provide a coating agent containing ultrafine particles.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention contain 100 to 10,000 parts by mass of tin oxide-based ultrafine particles with respect to 100 parts by mass of the water-dispersible polymer, and A group in which a solid surface concentration is 8% by mass or less, a hydrophilic organic solvent of 30% by mass or more is contained, and an appropriate viscosity is imparted so that a physical surface treatment such as corona discharge treatment is not performed. It has been found that a sufficient finish can be imparted and a good finished appearance can be obtained without deteriorating physical properties such as adhesion and printability, and the present invention has been reached based on this finding. did.

That is, the gist of the present invention is as follows.
(1) The content of the tin oxide ultrafine particles containing 100 parts by mass of the water dispersible polymer, tin oxide ultrafine particles, hydrophilic organic solvent, and water to make the water dispersible polymer 100 parts by mass is 100 to 10,000 parts by mass. A coating agent having a solid content concentration of 0.1 to 8% by mass and a hydrophilic organic solvent content of 30% by mass or more, at a temperature of 20 ° C. and a shear rate of 20.40 s ⁻¹ Viscosity at 50 to 500 mPa · s.
(2) The coating agent according to (1), wherein the viscosity at a temperature of 20 ° C. and a shear rate of 1.02 s ⁻¹ is 1000 to 7000 mPa · s.

  According to the coating agent of the present invention, an antistatic coating film excellent in adhesion, printability, and appearance can be formed even on a substrate surface that has not been subjected to physical surface treatment such as corona discharge treatment. A film or the like on which a coating film is formed can be favorably used for packaging electronic materials.

  Hereinafter, the present invention will be described in detail.

The viscosity of the coating agent in the present invention is related not only to the finished appearance but also to other coating film performance and work performance. For this reason, the viscosity (apparent viscosity) of the coating agent needs to be 50 to 500 mPa · s at 20 ° C. under a high shear rate (20.40 s ⁻¹ ), and more preferably 100 to 400 mPa · s. Yes, more preferably 150 to 300 mPa · s. When the viscosity exceeds 500 mPa · s, the coating film becomes uneven, and the finished appearance tends to be lowered. On the other hand, it is preferable that the viscosity at a high shear rate is low, but if it is less than 50 mPa · s, it is difficult to obtain an appropriate coating thickness because of excessive wetting and spreading.

The viscosity of the coating agent in the present invention preferably has a viscosity of 1000 to 7000 mPa · s under a low shear rate (1.02 s ⁻¹ ) in addition to the viscosity at the high shear rate described above. More preferably, it is ˜6000 mPa · s. If both the viscosity at the high shear rate and the viscosity at the low shear rate are in the specified range, the coating agent of the present invention has thixotropy (thixotropy) as a result. By imparting thixotropy to the coating agent, it is possible to increase the viscosity under a low shear rate (at rest) to suppress excessive wetting spread, while maintaining the viscosity under a high shear rate low. As a result, sufficient coating properties can be imparted to a substrate that has not been subjected to physical surface treatment such as corona discharge treatment, without deteriorating physical properties such as adhesion and water resistance, and good. A finished appearance can be obtained. When the viscosity at a low shear rate exceeds 7000 mPa · s, handling becomes difficult and workability is lowered. On the other hand, when it is less than 1000 mPa · s, the wetting spread resistance is lowered, and for example, it is difficult to obtain a thick film.

  The viscosity of the coating agent of the present invention is adjusted mainly by the content of the hydrophilic organic solvent, and can also be adjusted by adjusting the solid content concentration. For example, when the solid content concentration is lowered, the viscosity tends to decrease, and when the content of the hydrophilic organic solvent is increased, the viscosity tends to decrease.

  As described above, it is essential that the coating agent of the present invention contains a hydrophilic organic solvent. As the hydrophilic organic solvent, those having a solubility in water at 20 ° C. of 50 g / L or more are preferable, and specific examples thereof include methanol, ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, Examples thereof include dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether, and methanol, ethanol, n-propanol, and isopropanol are particularly preferable from the viewpoint of liquid stability and price.

  The amount of the hydrophilic organic solvent needs to be 30% by mass or more. Although the addition amount is adjusted by solid content concentration, 30-90 mass% is preferable, 40-80 mass% is more preferable, 50-70 mass% is further more preferable. If the amount of the hydrophilic organic solvent is less than 30% by mass, sufficient coatability may not be exhibited, and if it exceeds 90% by mass, the tin oxide ultrafine particles may aggregate.

  Moreover, the solid content concentration of the coating agent of the present invention is required to be 0.1 to 8% by mass. Although the addition amount is adjusted by the hydrophilic organic solvent content, 1 to 7% by mass is more preferable, and 2 to 6% by mass is more preferable. When the solid content concentration is 0.1% by mass or less, it becomes difficult to control the viscosity to an appropriate level, and it tends to be difficult to form a film having a sufficient thickness when applied to a substrate. On the other hand, when it exceeds 8 mass%, it may aggregate and a stable liquid may not be obtained.

  The coating agent in the present invention is prepared, for example, by mixing an aqueous dispersion of tin oxide ultrafine particles, an aqueous dispersion of a water-dispersible polymer, and a hydrophilic organic solvent. The mixing order is arbitrary, but in order to prepare a stable coating agent, after adding and stirring a hydrophilic organic solvent to an aqueous dispersion of tin oxide ultrafine particles, an aqueous dispersion of a water-dispersible polymer is added. In addition, a method of mixing is preferable.

  When preparing the coating agent, a known device is used as a stirring device for mixing the aqueous dispersion of tin oxide ultrafine particles, the aqueous dispersion of the water-dispersible polymer, and the hydrophilic organic solvent. Since the dispersibility of the mixed liquid is good, a simple mixing operation can be performed in a very short time.

  As described above, the fine particles of the water-dispersible polymer are used as an aqueous dispersion previously dispersed in water or a solvent containing water as a main component. A method for obtaining an aqueous dispersion of a water-dispersible polymer is not particularly limited, and a commercially available one may be used. A method of obtaining a resin and dispersing it or polymerizing a monomer in an aqueous medium. Obtainable. Aqueous dispersions of water-dispersible polymers can generally be classified into self-dispersing aqueous dispersions and forced dispersion-type aqueous dispersions. The aqueous dispersion of the water-dispersible polymer used in the present invention is a self-dispersing aqueous dispersion formed by neutralizing an anionic group contained in the water-dispersible polymer with a basic compound. Preferably there is. Those that are dispersed and stabilized by surfactants (cationic emulsifiers, anionic emulsifiers, nonionic emulsifiers, or amphoteric emulsifiers) or protective colloid compounds, such as forced dispersion type aqueous dispersions, depend on the dispersion stabilizer. When the coating film is formed, the coating film performance may be deteriorated.

  The number average particle system of the water-dispersible polymer in the aqueous dispersion is preferably 200 nm or less, more preferably 150 nm or less, still more preferably 100 nm or less. The volume average particle diameter is preferably 500 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less. If the number average particle diameter of the water-dispersible polymer exceeds 200 nm or the volume average particle diameter exceeds 500 nm, not only will it be difficult to develop thixotropy, but the transparency of the coating film may be reduced or the substrate may be reduced. Adhesiveness may be reduced.

  The number average particle diameter and volume average particle diameter of the water-dispersible polymer and tin oxide ultrafine particles described later are measured by a dynamic light scattering method.

  Examples of the water-dispersible polymer used in the present invention include polyolefin resins, polyester resins, polyurethane resins, acrylic resins, and the like. The water-dispersible polymer preferably contains the same type of resin as the thermoplastic resin substrate described later from the viewpoint of adhesion. For example, it is preferable to use a polyolefin resin when the substrate is a polyolefin resin such as polypropylene, and to use a polyester resin when the substrate is a polyester resin such as polyethylene terephthalate.

  A commercially available water-dispersible polymer can also be used. Examples of polyolefin resin water dispersions include Unitika Arrowbase Series, Mitsui Chemicals Chemipearl Series, Toho Chemicals High Tech Series, Sumitomo Seika Co., Ltd. Elitel series manufactured by Toyobo Co., Ltd., Bironal series manufactured by Toyobo Co., Ltd., Adekabon titer series manufactured by Asahi Denka Co., Ltd. and Takerak series manufactured by Mitsui Chemicals Co., Ltd. as water dispersions of polyurethane resin And so on.

  In the present invention, the tin oxide-based ultrafine particles refer to tin oxide-based compounds, or ultrafine particles of solvates and coordination compounds thereof, and have an average particle size of 200 nm or less and a sharp particle size distribution. is there. Specific examples thereof include tin oxide, antimony-doped tin oxide, indium-doped tin oxide, tin oxide-doped indium, aluminum-doped tin oxide, tungsten-doped tin oxide, titanium oxide-cerium oxide-tin oxide composite, and titanium oxide-oxide. Tin composites can be used, and solvates and ultrafine particles of coordination compounds can also be used. Tin oxide ultrafine particles are particularly preferred from the viewpoint of transparency and cost of the coating film.

  The method for producing the above tin oxide ultrafine particles is not particularly limited. For example, a method of hydrolyzing or thermally hydrolyzing metal tin or a tin compound, a method of alkaline hydrolysis of an acidic solution containing tin ions, and a solution containing tin ions. Any method such as a method of ion exchange using an ion exchange membrane or an ion exchange resin can be used.

  In the coating agent of the present invention, the tin oxide-based ultrafine particles used together with the above-described polymer are used as a sol dispersed in advance in water or a solvent containing water as a main component.

  The sol in the present invention is a fluid system in which a solid dispersoid having a size of about 1 to 100 nm is dispersed in a liquid dispersion medium, and the solid dispersoid has an active Brownian motion. It refers to the state of being dispersed to the extent that it passes through the filter paper or the state thereof. The production method of the tin oxide-based ultrafine particle sol is not particularly limited, but in general, many dispersions are stabilized by a basic compound, and an aqueous dispersion of a water-dispersible polymer that is stabilized by a basic compound. Such a thing is also preferable from the viewpoint of improving the mixing stability with the body.

  The number average particle diameter of the tin oxide ultrafine particles in the sol is preferably 50 nm or less, more preferably 30 nm or less, and particularly preferably 20 nm or less. The volume average particle diameter is preferably 200 nm or less, more preferably 50 nm or less, and particularly preferably 20 nm or less. When the number average particle diameter of the tin oxide compound exceeds 50 nm or the volume average particle diameter exceeds 200 nm, not only is it difficult to form a thin coating film uniformly, but the transparency of the coating film is reduced. Adhesion with the substrate may be reduced.

  A commercially available sol of tin oxide-based ultrafine particles can also be used. For example, there are EPS-6 manufactured by Yamanaka Chemical Co., Ltd. as the tin oxide aqueous dispersion, SN100D manufactured by Ishihara Sangyo Co., Ltd. as the antimony-doped tin oxide aqueous dispersion, and ITO manufactured by CI Chemical Co., Ltd. as the tin oxide-doped indium.

  The amount of the tin oxide-based ultrafine particles needs to be 100 to 10000 parts by mass with respect to 100 parts by mass of the polymer, preferably 400 to 9000 parts by mass, more preferably 800 to 8000 parts by mass, and 1200 to 7000 parts by mass. Part is more preferable. When the amount of the tin oxide ultrafine particles is less than 100 parts by mass, the antistatic performance and the like tend to be lowered, and when it exceeds 10,000 parts by mass, the adhesion with the substrate tends to be lowered.

  As a basic compound contained in an aqueous dispersion of a water-dispersible polymer or a tin oxide sol, ammonia or an organic amine compound that volatilizes at the time of coating film formation is preferable from the viewpoint of water resistance of the coating film, and a boiling point of 30 to An organic amine compound at 250 ° C. is preferable, and an organic amine compound at 50 to 200 ° C. is more preferable. When the boiling point is less than 30 ° C., handling becomes difficult. When the boiling point exceeds 250 ° C., it becomes difficult to disperse the organic amine compound from the resin coating film by drying, and the water resistance of the coating film may deteriorate.

  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, 3-methoxypropylamine, monoethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine and the like.

  The coating agent of the present invention includes a crosslinking agent, a lubricant, a pigment or a dye, an ultraviolet absorber, an antioxidant, a leveling agent, an antifoaming agent, an anti-waxing agent, a dispersing agent, etc., as long as the effects of the present invention are not impaired. Can be added.

  As the crosslinking agent, 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 complex having a polyvalent coordination site, etc. can be used. Of these, isocyanate compounds , Melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline group-containing compounds, zirconium salt compounds, silane coupling agents and the like are preferable. Moreover, you may use combining these crosslinking agents. Among these, an isocyanate compound and an oxazoline group-containing compound are preferable, and an oxazoline group-containing compound is more preferable because the coating film performance can be improved at a relatively low temperature. The addition amount is appropriate as long as it is 100 parts by mass or less with respect to 100 parts by mass of the water-dispersible polymer.

  Examples of the lubricant include waxes, silicone compounds, fatty acid amide compounds, fatty acid metal salt compounds, and the like. As waxes, plant waxes such as candelilla wax, carnauba wax, rice wax, and wax, animal waxes such as shellac wax and lanolin wax, mineral waxes such as montan wax and ozokerite, petroleum waxes such as paraffin wax and microcrystalline wax Examples thereof include polyethylene wax and polypropylene wax. The silicone compound is a compound having a silicon-oxygen bond (siloxane bond) in the molecule and an organic group bonded to the side chain of the silicon atom, and examples thereof include an alkylmethoxysilane compound and an alkylethoxysilane compound. . Examples of the fatty acid amide compound include stearic acid amide, bis stearic acid amide, and oleic acid amide. Examples of the fatty acid metal salt compound include zinc stearate and magnesium stearate.

  The content of non-volatile compounds such as surfactants (cationic emulsifiers, anionic emulsifiers, nonionic emulsifiers or amphoteric emulsifiers) and protective colloid compounds in the coating agent is water-dispersible in terms of adhesion to the substrate. The amount is preferably 5 parts by mass or less per 100 parts by mass of the polymer, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, and most preferably not added. This is because such a compound remains in the coating film even after drying, and may degrade the coating film performance over time.

  Examples of the coating method for the coating agent include gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, and brushing. After uniformly coating the surface of the material film, etc., it is possible to form a uniform resin coating in close contact with the surface of various substrate films, etc. by setting it near room temperature if necessary and subjecting it to a drying treatment. it can. As a heating device at this time, a normal hot air circulation type oven, an infrared heater, or the like may be used. In addition, the heating temperature and the heating time are appropriately selected depending on the properties of the substrate film that is the object to be coated. However, in consideration of economy, the heating temperature is 10 ° C. to (such as a film). The range of the melting point of the resin) is preferred. The heating time is usually in the range of 1 second to 20 minutes.

Preferably the coating amount of the coating film is 0.1 to 1 g / ^{m 2,} more preferably 0.2 to 0.8 g / ^{m 2,} more preferably 0.3 to 0.5 g / ^{m 2.} When the amount of lamination exceeds 1 g / m ² , the transparency of the coating film and the substrate adhesion deteriorate. When the stacking amount is less than 0.1 g / m ² , the antistatic performance deteriorates. The antistatic performance can be evaluated by a surface specific resistance value, and from the viewpoint of suppressing adhesion of dust, dust and the like, it is practically preferable if this value is less than 10 ¹¹ Ω / □.

  As a base material to which the coating agent is applied, a thermoplastic resin is preferable, and a molded body, a film, a sheet, a synthetic paper, and the like made of the thermoplastic resin are exemplified. From the viewpoint of sufficiently exerting the coating film performance, as the thermoplastic resin, polyolefin resin such as polyethylene, polypropylene, ionomer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, cyclic polyolefin resin, nylon 6, Polyamide resins such as nylon 66 and nylon 46, polyethylene terephthalate (hereinafter referred to as PET), amorphous PET (A-PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, Examples thereof include polyester resins such as polylactic acid, polystyrene resins, polyimide resins, polycarbonate resins, polyarylate resins, and mixtures thereof. These thermoplastic resin films or sheets (hereinafter referred to as films) are preferably used, and the haze of the substrate is preferably 10% or less, more preferably 5% or less. Moreover, as a film etc., single bodies, such as a film consisting of the said resin, or laminated bodies, such as a film, are mentioned. Since the antistatic coating agent of the present invention is excellent in wettability, the substrate need not be subjected to physical surface treatment, but may be applied. Here, the physical surface treatment means a surface treatment using light, electron beam, ion beam, plasma or the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, as a base material, PP sheet (300 micrometers in thickness, Super Pure Array by Idemitsu Unitech Co., Ltd.) (henceforth, SP), A-PET sheet (Mitsubishi Chemical Corporation, thickness 200 micrometers) (henceforth AP), stretched polypropylene film ( Tosero Co., Ltd., OP U-1, thickness 20 μm) (hereinafter, PP) or biaxially stretched polyethylene terephthalate film (Unitika's Emblet PET12, thickness 12 μm) was used. Various evaluations were carried out after leaving the coated film or the like for 1 day in an atmosphere of a temperature of 23 ° C. and a humidity of 65%.

(1) Antistatic properties Based on JIS-K6911, using a digital ultrahigh resistance / microammeter R83340 manufactured by Advantest Co., Ltd. The measurement was performed in an atmosphere of 65 ° C. and a humidity of 65%.

(2) Viscosity and shear rate
BROOKFIELD ENGINEERING LABORATORIES, INC. B-type viscous clock SYNCHRO-LECTRIC VISCOMETER Model LVT (Spindle 31) was used and measured at a temperature of 20 ° C. The measurement was performed at a rotor rotational speed of 3 rpm as a low shear rate condition and 60 rpm as a high shear rate condition. The shear rate was converted by multiplying the rotor speed by 0.34.

(3) Coating amount (coating amount)
A predetermined amount of the coating liquid of the present invention was applied to a substrate whose area and mass were measured in advance, and dried at 60 ° C. for 30 seconds. The mass of the obtained laminate was measured, and the coating amount was determined by subtracting the mass of the base material before coating. The coating amount per unit area (g / m ² ) was calculated from the coating amount and the coating area.

(4) Haze Based on JIS-K7361-1, the haze measurement of a film etc. (laminated body) was performed using the turbidimeter (Nippon Denshoku Industries Co., Ltd. make, NDH2000). However, this evaluation value is the turbidity (SP: 3.1%, AP: 0.7%, PP: 2.4%, PET: 2.8%) of the base film used in each example. Contains.

(5) Appearance The surface appearance of the coated film was visually determined.
○: Uneven, ×: Uneven

(6) Adhesiveness It evaluated by classifying into a sheet and a film.
(6) -1 Adhesiveness of Sheet (SP, AP) Adhesiveness between the base film and the coating film was evaluated by tape peeling (cross cut test) by the cross-cut method described in JIS K5400. The coated layer was cut into 100 sections by cross-cutting, and the number of sections of the coated layer remaining after the tape peeling was evaluated according to the following criteria.
○: 100 section remaining, Δ: 90 to 99 section remaining, x: 0 to 89 section remaining (6) -2 Adhesiveness of film (PP, PET) Adhesive tape (TF- manufactured by Nichiban Co., Ltd.) After pasting 12), the tape was peeled off vigorously. The state of the coating film surface was visually observed and evaluated as follows.
○: No peeling at all, Δ: Some peeling occurred, ×: All peeling off.

(7) Particle size The number average particle size and volume average particle size of the binder resin and the tin oxide compound were measured by a dynamic light scattering method using a Microtrac particle size distribution analyzer UPA150 (Model No. 9340) manufactured by Nikkiso Co., Ltd. did.

(8) Printability (ink wettability)
The wettability (degree of repellency) of ink when water-based ink (Aqua Ecole JW 224, manufactured by Toyo Ink Manufacturing Co., Ltd.) was gravure printed on a coating film was evaluated.
○: No ink repelling ×: Ink repelling

<Polymer aqueous dispersion>

(Polyolefin resin aqueous dispersion)
As the polyolefin resin aqueous dispersion, a commercially available dispersion O-1 (manufactured by Unitika, Arrow Base SB-1200, solid content concentration: 25.2 mass%, isopropanol: 20 mass%) was used. Both the number average particle diameter and the volume average particle diameter were 100 nm or less.

(Polyester resin aqueous dispersion)
As the polyester resin aqueous dispersion, a commercially available dispersion P-1 (manufactured by Unitika, Elitel KZA-3556, solid content concentration: 30% by mass, isopropanol: 22% by mass) was used. Both the number average particle diameter and the volume average particle diameter were 100 nm or less.

(Polyurethane resin aqueous dispersion)
As the polyurethane resin aqueous dispersion, a commercially available dispersion U-1 (Asahi Denka Kogyo Co., Ltd., Adekabon titer HUX-232, solid concentration: 30% by mass, N-methylpyrrolidone: 10% by mass) was used. Both the number average particle diameter and the volume average particle diameter were 100 nm or less.

<< Preparation of tin oxide sol >>

(Preparation of tin oxide sol)
Dissolve 35 g (0.1 mol) of stannic chloride pentahydrate in 200 ml of water to make a 0.5 M aqueous solution, and add 28% aqueous ammonia with stirring to add white tin oxide with a pH of 1.5 An ultrafine particle-containing slurry was obtained. The obtained tin oxide ultrafine particle-containing slurry is heated to 70 ° C. and then naturally cooled to around 50 ° C., and then pure water is added to obtain a 1 L tin oxide ultrafine particle-containing slurry, and solid-liquid separation is performed using a centrifuge. went. After adding 800 ml of pure water to this water-containing solid content, stirring and dispersing with a homogenizer, washing was performed by solid-liquid separation using a centrifuge. 75 ml of pure water was added to the water-containing solid content after washing to prepare a tin oxide ultrafine particle-containing slurry.

  To the obtained tin oxide ultrafine particle-containing slurry, 3.0 ml of triethylamine was added and stirred, and when the transparency appeared, the temperature was raised to 70 ° C., then the heating was stopped and the solid content was cooled to 11.5 mass. Tin oxide sol Z-1 containing 1% of organic amine as a dispersion stabilizer was obtained. The number average particle diameter and the volume average particle diameter were 8.5 nm and 9.8 nm, respectively.

Example 1
After adding water (7 g) to the tin oxide sol Z-1 (35 g), 64 g of n-propanol (amount that the total amount of the solvent contained in the coating agent is 60% by mass) was added to obtain a sol. A coating agent was prepared by mixing 1 g of the polyolefin resin aqueous dispersion O-1 (corresponding to 1600 parts by mass of tin oxide ultrafine particles with respect to 100 parts by mass of the polyolefin resin solid content). When the viscosity was measured, the viscosity at a shear rate of 20.40 s ⁻¹ was 224 mPa · s, the viscosity at a shear rate of 1.02 s ⁻¹ was 2500 mPa · s, and it was thixotropic. The coating agent prepared on various substrates was coated such that the coating amount after drying (coating amount) was 0.2 g / m ² and then dried at 60 ° C. for 30 seconds to obtain a coated film.

Example 2
After adding water (5.7 g) to the tin oxide sol Z-1 (35 g), 61 g of n-propanol (amount in which the total amount of the solvent contained in the coating agent is 60% by mass) was added to obtain a sol. Here, 0.25 g of polyolefin resin aqueous dispersion O-1 (corresponding to 6400 parts by mass of tin oxide ultrafine particles with respect to 100 parts by mass of polyolefin resin solid content) was mixed to prepare a coating agent. When the viscosity was measured, the viscosity at a shear rate of 20.40 s ⁻¹ was 279 mPa · s, the viscosity at a shear rate of 1.02 s ⁻¹ was 5200 mPa · s, and it was thixotropic. The coating agent prepared on various substrates was coated such that the coating amount after drying (coating amount) was 0.2 g / m ² and then dried at 60 ° C. for 30 seconds to obtain a coated film.

Example 3
After adding water (12 g) to tin oxide sol Z-1 (35 g), 74.7 g of n-propanol (amount in which the total amount of solvent contained in the coating agent is 60% by mass) was added to obtain a sol. 4 g of polyolefin resin aqueous dispersion O-1 was mixed here (equivalent to 400 parts by mass of tin oxide ultrafine particles with respect to 100 parts by mass of polyolefin resin solids) to prepare a coating agent. Measurement of the viscosity, a viscosity at a shear rate of 20.40s ^-1 200mPa · s, the viscosity at a shear rate of 1.02s ^-1 is 1500 mPa · s, had thixotropic properties. The coating agent prepared on various substrates was coated such that the coating amount after drying (coating amount) was 0.2 g / m ² and then dried at 60 ° C. for 30 seconds to obtain a coated film.

Example 4
After adding water (7 g) to the tin oxide sol Z-1 (35 g), 64 g of n-propanol (amount that the total amount of the solvent contained in the coating agent is 60% by mass) was added to obtain a sol. 0.8 g of polyester resin aqueous dispersion P-1 (equivalent to 1600 parts by mass of tin oxide ultrafine particles per 100 parts by mass of polyester resin solids) was mixed here to prepare a coating agent. When the viscosity was measured, the viscosity at a shear rate of 20.40 s ⁻¹ was 224 mPa · s, the viscosity at a shear rate of 1.02 s ⁻¹ was 2500 mPa · s, and it was thixotropic. The coating agent prepared on various substrates was coated such that the coating amount after drying (coating amount) was 0.2 g / m ² and then dried at 60 ° C. for 30 seconds to obtain a coated film.

Example 5
After adding water (7 g) to the tin oxide sol Z-1 (35 g), 64 g of n-propanol (amount that the total amount of the solvent contained in the coating agent is 60% by mass) was added to obtain a sol. A coating agent was prepared by mixing 0.8 g of polyurethane resin aqueous dispersion U-1 (corresponding to 1600 parts by mass of tin oxide ultrafine particles with respect to 100 parts by mass of polyurethane resin solid content). When the viscosity was measured, the viscosity at a shear rate of 20.40 s ⁻¹ was 204 mPa · s, the viscosity at a shear rate of 1.02 s ⁻¹ was 2300 mPa · s, and it was thixotropic. The coating agent prepared on various substrates was coated such that the coating amount after drying (coating amount) was 0.2 g / m ² and then dried at 60 ° C. for 30 seconds to obtain a coated film.

Comparative Example 1
After adding water (60.4 g) to tin oxide sol Z-1 (35 g), 10.5 g of n-propanol (amount in which the total amount of solvent contained in the coating agent is 10% by mass) was added. 1 g of polyolefin resin aqueous dispersion O-1 was mixed here (equivalent to 1600 parts by mass of tin oxide ultrafine particles with respect to 100 parts by mass of polyolefin resin solids) to prepare a coating agent having a solid content concentration of 4% by mass. When the viscosity was measured, the viscosity at a shear rate of 20.40 s ⁻¹ was 5 mPa · s, and the viscosity at a shear rate of 1.02 s ⁻¹ was 5 mPa · s. An attempt was made to apply the coating agent prepared on various substrates so that the coating amount (coating amount) after drying was 0.2 g / m ² , but remarkable repellency occurred and the coating agent could not be applied.

Comparative Example 2
To tin oxide sol Z-1 (35 g), 15 g of n-propanol (amount so that the total amount of the solvent contained in the coating agent was 30% by mass) was added. Here, 1 g of polyolefin resin aqueous dispersion O-1 (corresponding to 1600 parts by mass of tin oxide ultrafine particles per 100 parts by mass of polyolefin resin solids) was mixed to prepare a coating agent having a solid content concentration of 8.5% by mass. It could not be evaluated because it aggregated and did not disperse even when a shearing force was applied.

Comparative Example 3
After adding water (17.7 g) to the tin oxide sol Z-1 (35 g), 53.3 g of n-propanol (amount in which the total amount of the solvent contained in the coating agent is 50% by mass) was added. 1 g of polyolefin resin aqueous dispersion O-1 was mixed here (equivalent to 1600 parts by mass of tin oxide ultrafine particles with respect to 100 parts by mass of polyolefin resin solids) to prepare a coating agent having a solid content concentration of 4% by mass. When the viscosity was measured, the viscosity at a shear rate of 20.40 s ⁻¹ was 5 mPa · s, and the viscosity at a shear rate of 1.02 s ⁻¹ was 5 mPa · s. An attempt was made to apply the coating agent prepared on various substrates so that the coating amount (coating amount) after drying was 0.2 g / m ² . When the coating amount after drying was measured, it was 0.07 g / m ² .

Comparative Example 4
To the tin oxide sol Z-1 (35 g), 70 g of a solution obtained by dissolving 4 g of polyvinyl alcohol (JC-25, manufactured by Nihon Vinegar Poval Co., Ltd.) in water (66 g) was added, and then an aqueous polyolefin resin dispersion O-1 was added. 1 g (corresponding to 1600 parts by mass of tin oxide ultrafine particles per 100 parts by mass of polyolefin resin solids) was mixed to prepare a coating agent having a solids concentration of 7.8% by mass. Measurement of the viscosity, a viscosity at a shear rate 20.40S ^-1 is 30 mPa · s, the viscosity at a shear rate of 1.02s ^-1 was 50 mPa · s. An attempt was made to apply the coating agent prepared on various substrates so that the coating amount (coating amount) after drying was 0.2 g / m ² , but remarkable repellency occurred and the coating agent could not be applied.

Comparative Example 5
To the tin oxide sol Z-1 (35 g), 71 g of a solution obtained by dissolving 6 g of polyvinyl alcohol (JC-25 manufactured by Nippon Vinegar Poval Co., Ltd.) in water (65 g) was added, and then an aqueous polyolefin resin dispersion O-1 was added. 1 g (equivalent to 1600 parts by mass of tin oxide ultrafine particles per 100 parts by mass of polyolefin resin solids) was mixed to prepare a coating agent having a solids concentration of 8.7% by mass. When the viscosity was measured, the viscosity at a shear rate of 20.40 s ⁻¹ was 300 mPa · s, and the viscosity at a shear rate of 1.02 s ⁻¹ was 350 mPa · s. The coating agent prepared on various substrates was coated such that the coating amount after drying (coating amount) was 0.2 g / m ² and then dried at 60 ° C. for 30 seconds to obtain a coated film.

  Table 1 summarizes the results of Examples 1 to 5 and Comparative Examples 1 to 5.

  As shown in Examples 1 to 5, the coating agent of the present invention can be applied to a film that has not been surface-treated, and the coating film has antistatic properties, adhesion, transparency, appearance, and printability. It was excellent. It was confirmed that a coating agent showing excellent performance could be prepared regardless of the type of the water-dispersible polymer (Examples 1, 4, and 5). It was confirmed that the antistatic property was improved when the ratio of the tin oxide compound was increased (Examples 1 to 3). It was confirmed that the performance developed regardless of the substrate (Examples 1 to 5). On the other hand, when the viscosity is outside the range of the present invention, a stable coating agent or coating amount cannot be obtained, the antistatic property is deteriorated, and the appearance is not satisfactory (Comparative Examples 1 to 3). In order to prepare a coating material having a viscosity within the range of the present invention by adding a thickening agent, a large amount of the thickening agent is necessary (Comparative Example 4). Since the ratio of the tin oxide compound occupying in the film decreased, the antistatic property decreased and the adhesion was inferior (Comparative Example 5).

Claims (2)

The content of the tin oxide ultrafine particles containing a water dispersible polymer, tin oxide ultrafine particles, a hydrophilic organic solvent, and water to make 100 parts by mass of the water dispersible polymer is 100 to 10,000 parts by mass, and A coating agent having a solid content concentration of 0.1 to 8% by mass and a hydrophilic organic solvent content of 30% by mass or more, having a viscosity at a temperature of 20 ° C. and a shear rate of 20.40 s ⁻¹ . A coating agent characterized by having a viscosity of 50 to 500 mPa · s. The coating agent according to claim ^1, wherein the viscosity at a temperature of 20 ° C. and a shear rate of 1.02 s ⁻¹ is 1000 to 7000 mPa · s.