JP2005320408A - Glass container and aqueous coating agent therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous coating agent for a glass container, which dries at an ordinary temperature, has a water resistance and an alkali removability, has a light-blocking property for inhibiting deterioration of contents caused by light corresponding to ultraviolet to visible ray wavelengths and is excellent in appearance design. <P>SOLUTION: The aqueous coating agent for the glass container contains an acrylic resin emulsion having a film-forming property and a hydrophilic dyestuff which absorbs light ranging from ultraviolet to visible ray wavelengths. The glass container is coated with the aqueous coating agent for the glass container. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aqueous coating agent for glass containers and a glass container coated with the coating material. More specifically, the present invention relates to an aqueous coating agent for glass containers that is excellent in alkali peelability, water resistance, light-shielding properties, and appearance design by drying at room temperature, and a glass container coated with the coating.

  For glass bottles for beer and drinks, brown glass containers are used for the purpose of preventing the contents from being altered by light. However, these brown glass containers use iron oxide so-called bengara to secure light shielding properties, but it is known that the ability to shield light with a wavelength of 450 nm or more is inferior, and in the case of beer, hop alteration It has been reported to generate a sunlight odor due to Also, drinks are known to be altered in content components such as various vitamins.

  For this reason, a coating agent for glass containers that blocks light with a wavelength of 450 nm to 550 nm has been proposed for the purpose of preventing deterioration of the contents (see, for example, Patent Document 1). However, since the above proposal contains a pigment, it has the ability to block light with a wavelength of 450 nm or more, but when applied to a brown bottle, the appearance of the container appears whitish and appears dusty under daylight. The product value was lowered. This phenomenon is presumably caused mainly by the particle size of the pigment. Therefore, it is a water-based paint so far, but the coating agent does not peel off from the glass container even if immersed in water after drying at room temperature, and the alkali releasability that it can be easily peeled off when washed with an alkaline aqueous solution. In addition, a light-shielding coating material that has the following characteristics and blocks light with a wavelength of 450 nm or more and does not cause white blur in daylight has not been obtained.

JP 2001-279185 A

  An object of the present invention is a room temperature drying type which has water resistance and alkali peelability, and has light shielding properties for suppressing deterioration of contents caused by light corresponding to ultraviolet to visible light, and is excellent in appearance design. The object is to provide an aqueous coating agent for glass containers.

  As a result of intensive studies on the water-based coating for glass containers, the present inventors have found that a water-based coating for glass containers having a resin composition having a specific film-forming property and a hydrophobic dye that shields a specific wavelength from light. It has been found that even in a dry state, it has properties required for an aqueous coating agent for glass containers, such as water resistance and alkali peelability, and also has light-shielding properties and appearance design properties, thereby completing the present invention.

  That is, the present invention firstly provides an aqueous coating agent for glass containers comprising an acrylic resin emulsion having a film-forming property and a hydrophobic dye having an absorption region in the ultraviolet to visible wavelength region. provide.

Secondly, the present invention provides a glass container formed by coating the above-described aqueous coating agent for glass containers.

  The glass container formed by coating the aqueous coating agent for a glass container of the present invention is excellent in alkali peelability, water resistance, light-shielding property and appearance design, and can be used, for example, for beer bottles and glass bottles for drinks.

  Hereinafter, the present invention will be described in detail. The acrylic resin emulsion having a film-forming property in the present invention is an acrylic resin emulsion that has fluidity before coating and can form a continuous film after coating and room temperature curing, and has alkali peelability and water resistance. It is what you have.

  The radical polymerizable unsaturated monomer constituting the acrylic resin emulsion used in the aqueous coating agent for glass containers of the present invention is particularly limited as long as it is a compound having a radical polymerizable unsaturated group in one molecule. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate , Acrylic unsaturated monomers of alkyl (meth) acrylates having 1 to 30 carbon atoms such as nonyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate,

  Carboxylic acid group-containing unsaturated monomers such as (meth) acrylic acid, itaconic acid or monoester thereof, maleic acid or monoester thereof, fumaric acid or monoester thereof, crotonic acid, p-vinylbenzoic acid, and salts thereof ,

  2- (meth) acrylamide-2-methylpropanesulfonic acid, vinylsulfonic acid, styrenesulfonic acid, (meth) allylsulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, α-methylstyrenesulfonic acid, etc. Sulfonic acid group-containing unsaturated monomers and salts thereof,

  Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, vinylpyrrolidone, N-methylvinylpyridium chloride, (meth) allyltriethylammonium chloride, 2-hydroxy-3- (meth) acryloxypropyltrimethylammonium chloride, etc. A tertiary or quaternary amino group-containing unsaturated monomer,

  Hydroxyl-containing unsaturated monomers such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate; (meth) acrylamide, N-hydroxyalkyl (meth) acrylamide, N-alkyl (meta ) Amide group-containing unsaturated monomers such as acrylamide, N, N-dialkyl (meth) acrylamide, vinyl lactams,

  Unsaturated dibasic acid diesters such as maleic acid, fumaric acid, itaconic acid, aromatic unsaturated monomers such as styrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, chloromethylstyrene, vinyltoluene Body, nitrile unsaturated monomers such as acrylonitrile, methacrylonitrile, conjugated diolefin unsaturated monomers such as butadiene, isoprene, divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate , Polyfunctional unsaturated monomers such as allyl methacrylate, diallyl phthalate, trimethylolpropane triacrylate, glyceryl diallyl ether, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, ethylene, propylene Vinyl ester monomers such as vinyl unsaturated monomers such as isobutylene, vinyl acetate, vinyl propionate, octyl vinyl ester, Veova 9, Veova 10 and Veova 11 (Beova: Shell Chemical Company) Saturated monomers, vinyl ether unsaturated monomers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, allyl ether unsaturated monomers such as ethyl allyl ether, vinyl chloride, vinyl bromide, vinylidene chloride, fluoride Halogen-containing unsaturated compounds such as vinylidene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, pentafluoropropylene, perfluoro (propyl vinyl ether), perfluoroalkyl acrylate, and fluoromethacrylate Sum monomer, etc.

  Epoxy group-containing unsaturated monomers such as glycidyl acrylate and glycidyl methacrylate, acrolein, diacetone acrylamide, vinyl methyl ketone, vinyl butyl ketone, diacetone acrylate, acetonitryl acrylate, acetoacetoxyethyl (meth) Carbonyl group-containing unsaturated monomers such as acrylate, vinyl acetophenone, vinyl benzophenone, etc.

  Vinylsilane-based unsaturated monomers such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycyl Epoxysilane unsaturated monomers such as Sidoxypropylmethyldiethoxysilane and 3-Glycidoxypropyltriethoxysilane, Styrylsilane unsaturated monomers such as p-styryltrimethoxysilane, 3-Methacryloxypropyl Methacryloxysilane unsaturated monomers such as methyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxy Acryloxysilane unsaturated monomers such as orchid, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3- Examples include aminosilane unsaturated monomers such as aminopropyltrimethoxysilane.

  As the radically polymerizable unsaturated monomer constituting the acrylic resin emulsion used in the aqueous coating agent for glass containers of the present invention, in particular, a silane coupling containing a (meth) acrylic acid monomer and a radically polymerizable unsaturated group An emulsion having an agent is preferred. As a usage-amount of the (meth) acrylic acid monomer in acrylic resin emulsion, about 1-20 mass parts is preferable normally with respect to 100 mass parts of solid content of this emulsion, More preferably, 2-15 mass parts Degree. When the amount of the (meth) acrylic acid monomer used is more than 20 parts by mass, the water resistance of the resulting coating tends to be reduced. Tend to be inferior.

  The amount of the silane coupling agent containing the radically polymerizable unsaturated group described above is usually preferably about 0.05 to 5 parts by mass, more preferably about 100 parts by mass of the solid content of the emulsion. About 0.1 to 2 parts by mass. If the amount of the silane coupling agent used is more than 5 parts by mass, the homogeneity of the film tends to decrease or the storage stability of the composition tends to decrease. When the amount is small, the water resistance tends to be insufficient and the adhesion to the glass container tends to be lowered.

  The glass transition temperature (Tg) of the acrylic resin emulsion is preferably 15 to 40 ° C. For this reason, it is preferable to appropriately select the radically polymerizable unsaturated monomer from the above-mentioned radically polymerizable unsaturated monomer so that the glass transition temperature is reached. When Tg is less than 15 ° C., scratch resistance and water resistance tend to be inferior, and when it exceeds 40 ° C., adhesion becomes poor and peeling of the coating film easily occurs. Inferior, it is necessary to use a large amount of film-forming aid (solvent, plasticizer), which is not preferable.

  Specific examples of the acrylic resin emulsion include (meth) acrylic acid- (meth) acrylic acid ester copolymer emulsion, styrene- (meth) acrylic acid, including a silane coupling agent containing a radical polymerizable unsaturated group. Copolymer emulsion, styrene- (meth) acrylic acid- (meth) acrylic ester copolymer emulsion, ethylene-vinyl acetate- (meth) acrylic acid copolymer emulsion, ethylene-vinyl acetate- (meth) acrylic acid- (Meth) acrylic acid ester copolymer emulsions and the like are mentioned, and among them, (meth) acrylic acid- (meth) acrylic acid ester copolymer emulsions are preferable.

  Examples of the silane coupling agent used as the radical polymerizable unsaturated monomer constituting the acrylic resin emulsion used in the aqueous coating agent for glass containers of the present invention include, for example, vinyl group-containing alkoxysilanes and (meth) acrylic groups. Examples thereof include silane coupling agents such as containing alkoxysilane and partial hydrolysates thereof.

  Specifically, vinyl group-containing silanes such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldisilane. Examples include (meth) acryloyl group-containing silanes such as ethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

  Particularly preferable silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane and the like.

  These vinyl group and (meth) acryl group-containing silane coupling agents can be easily incorporated into the acrylic resin emulsion by copolymerization with the above-mentioned radical polymerizable unsaturated monomer.

  A silane coupling agent other than the vinyl group-containing alkoxysilane may be used in combination as long as the performance is not impaired.

  In the production of the acrylic resin emulsion used in the present invention, a general emulsion polymerization method can be used, for example, a radically polymerizable unsaturated monomer in a nitrogen atmosphere in a reaction layer charged with water and an emulsifier, It is produced by dropping a polymerization initiator and carrying out a polymerization reaction. In order to produce an acrylic resin emulsion that is particularly excellent in water resistance, it is effective to reduce the low molecular weight components. For this purpose, it is necessary to reduce the amount of emulsifier used for emulsion polymerization, but it is most effective. A typical method is to reduce the number of radicals derived from the polymerization initiator relative to the radically polymerizable unsaturated monomer present in the polymerization system. From this point of view, any method of reducing the amount of the polymerization initiator used, or polymerizing using a so-called redox initiator at a low temperature, particularly a polymerization temperature of 50 ° C. or less, or extending the polymerization time, or a combination thereof Is effective.

  Moreover, surfactant (emulsifier) can be used in the range of 0.1-1 mass part with respect to 100 mass parts of polymerizable unsaturated monomers as needed. The emulsifier at this time is not particularly limited, but conventionally known emulsifiers can be used.

  Anionic emulsifiers such as alkyl sulfates, alkane sulfonates, alkyl benzene sulfonates, alkyl aryl polyether sulfates, (di) alkyl sulphosuccinates, polyoxyethylene alkyl phenyl sulfates, etc.

  Nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene-polyoxypropylene block copolymer, etc .: cationic emulsifiers such as cetyltrimethylammonium bromide, lauryl pyridinium chloride,

  (Meth) acrylic acid polyoxyethylene ammonium sulfate, (meth) acrylic acid polyoxyethylene sulfonic acid soda, polyoxyethylene alkenyl phenyl sulfonic acid ammonium, polyoxyethylene alkenyl phenyl sodium sulfate, sodium allylalkylsulfosuccinate, (meth) Anionic reactive emulsifiers such as polyoxypropylene sulfonate acrylate, 2-hydroxyethyl (meth) acryloyl phosphate,

  Nonionic reactive emulsifiers such as polyoxyethylene alkenyl phenyl ether and polyoxyethylene (meth) acryloyl ether can be used.

  Commonly available reactive emulsifiers such as Aqualon HS-10, HS-20, New Frontier A-229E (above, manufactured by Daiichi Kogyo Seiyaku), Adeka Soap SE-3N, SE-10N, SE-20N , SE-30N (above, manufactured by Asahi Denka Kogyo Co., Ltd.), AntoxMS-60, MS-2N, RA-1120, RA-2614 (above, made by Nippon Emulsifier), Eleminor JS-2, RS-30 (above, Sanyo Chemical Industries) Anionic reactive emulsifiers such as Latemulu S-120A, S-180A, S-180 (above, manufactured by Kao), Aqualon RN-20, RN-30, RN-50, New Frontier N-177E (above, Daiichi Kogyo Seiyaku Co., Ltd.), Adeka Soap NE-10, NE-20, NE-30, NE-40 (above, manufactured by Asahi Denka Kogyo), RMA-564, RMA-568, RMA-1 14 (or more, manufactured by Nippon Nyukazai) may be used without any problem nonionic reactive emulsifier or the like, as long as it is generally used to emulsion polymerization reaction such.

  Other dispersion stabilizers other than the emulsifier include, for example, polyvinyl alcohol, cellulose and derivatives thereof, starch and derivatives thereof, styrene maleic acid resin, maleated polybutadiene, maleated alkyd resin, polyacrylic acid (salt), polyacrylamide, Synthetic or natural water-soluble polymers such as water-soluble acrylic resins, sulfonated products of melamine formalin condensates, and polyvinyl pyrodrine. Of course, other commercially available emulsifiers and water-soluble polymers can be used, and two or more of these can be used in combination.

  The polymerization initiator used for the preparation of the acrylic resin emulsion constituting the aqueous coating agent for glass containers of the present invention may be one that is usually used for emulsion polymerization and is not particularly limited. Persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate, azobisisobutyronitrile, 2,2′-azobisdimethylvaleronitrile, 2,2′-azobis (2-aminodipropane) dihydrochloride Salts, such as azo compounds such as salts, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 4,4'-azobis (4-cyanovaleric acid), etc. Cumene hydroperoxide, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-te La methyl butyl hydroperoxide, 2,5-organic peroxides such as dimethyl-2,5-dihydro peroxide, hydrogen peroxide, and the like.

  Known using a combination of a persulfate or peroxide, a metal ion such as iron ion or copper ion, and a reducing agent such as glucose, dextrose, sodium sulfooxylate formaldehyde, sodium pyrosulfite, or L-ascorbic acid (salt) Redox type initiators can also be used. Further, examples of the chelating agent include sodium pyrophosphate and ethylenediamine tetraacetate. These usage-amounts can be suitably changed according to the combination of each initiator.

  As said polymerization initiator, only 1 type may be used and 2 or more types may be mixed suitably. Moreover, the usage-amount of these initiators can be suitably changed with the kind, usage-amount, etc. of the monomer to be used.

  The temperature at the time of polymerization may be within a range that is used in a known technique, and is performed under normal pressure or under pressure when a gaseous unsaturated monomer is used. The polymerization time in the radical polymerization reaction may be appropriately set according to the type and amount of the monomer used, but is preferably about 2 to 30 hours.

  The aqueous coating agent for glass containers according to the present invention is a hydrophobic dye for shielding light having a wavelength corresponding to ultraviolet to visible light in order to prevent the light from being transmitted through the glass container and the contents from being altered. Are blended. The amount of the dye used is appropriately set depending on the degree of coloration of the glass container, the film thickness of the coating agent, and the extinction coefficient of the dye. Usually, the light transmittance at 500 nm transmitted through the coated glass container is 5%. An amount of light shielding to a degree or less, preferably about 1% or less is used. Further, in order to maintain the brown appearance of the coating material of the brown glass container, the light transmittance of about 600 nm or more transmitted through the coated glass container is preferably about 25% or more.

  Examples of the hydrophobic dye used in the aqueous coating agent for glass containers of the present invention include nitro, benzeneazo, naphthaleneazo, heterocyclic azo, stilbene, triphenylmethane, xanthene, quinoline, and polymethine. Examples include hydrophobic dyes that block light with a wavelength of 450 to 550 nm, such as azomethine, azomethine, thiazole, quinoneimine, anthraquinone, indigoid, and phthalocyanine. For example, in order to maintain a brown image in a beer bottle, it is preferable to use a combination of various dyes that shield light of 450 to 550 nm as much as possible.

  Specifically, Dianix Red AC-E01 (Dyster Japan), Dianix Orange UN-SE01 (Dystar Japan), Dianix Red UN-SE (Dystar Japan), Dianix Rubine UN-SE ( Dystar Japan), Dianix Orange PLUS (Dystar Japan), Dianix Red PLUS (Dystar Japan), Dianix Rubine PLUS (Dystar Japan), Kalonon Polyester Yellow Brown 3RL 200 (Nippon Kayaku) Kayalon Polyester Dark Brown AS 200 (Nippon Kayaku), Kayalon Polyester Dark Brown TS 200 (Nippon Kayaku), Kayalon Polyester Scarlet 2R-E (Nippon Kayaku), Kayalon Polyester Red BR -S (Nippon Kayaku Co., Ltd.) etc. are illustrated.

  In the aqueous coating agent for glass containers of the present invention, if necessary, butyl carbitol, triethoxy carbitol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4 -Trimethyl-1, 3-pentanediol diisobutyrate, diethylene glycol mono-2-ethylhexyl ether, dibutyl sebacate, dibutyl citrate, acetyl tributyl citrate, diethylene glycol monobutyl ether acetate, 4-methyl-2-oxo-1 , 3-dioxolane, 3-methyl-3-methoxybutyl acetate, dipropylene glycol-n-butyl ether, dimethyl succinate, dimethyl glutarate, dimethyl adipate, tributyl phosphate, tributoxyethyl phosphate , Dioctyl adipate, Dibutyl diglycol adipate, Bis (2-ethylhexyl) azelate, Dioctyl sebacate, pH adjusters such as ammonia water, sodium hydroxide, leveling agents, viscosity modifiers, surfactants , Water-repellent agents, antifoaming agents, plasticizers, UV absorbers, penetrating agents, crosslinking agents, antistatic agents, polymerization inhibitors, adhesion-imparting agents, surface conditioners, antioxidants, waxes, etc. may be added. . In addition, a silicone resin may be added as long as the adhesiveness between the label and the coating agent with the casein adhesive is not significantly reduced.

  Examples of the glass container of the present invention include glass containers such as brown glass bottles, transparent glass bottles, and colored glass bottles. Among them, brown containers such as beer bottles and drink bottles that are beverage containers whose contents are easily altered by light. It is suitable to use for this glass container.

  Examples of the method for coating the glass container with the aqueous coating agent for glass containers of the present invention include, for example, a method using a roller type coating apparatus, a coating belt type coating apparatus or a spray type coating apparatus, brush coating, puff coating, transfer method, There are methods such as an immersion method and a flow coater method. After the glass container is coated with the coating agent, the target glass container can be usually produced by drying for about 0 to 48 hours. After the coating agent is coated on the glass container, air blowing, heat treatment, or the like may be performed as necessary in order to shorten the drying time.

  The dry film thickness on the glass container surface of the aqueous coating agent for glass containers of the present invention is usually about 0.5 to 30 μm, preferably 1 to 20 μm, and particularly preferably 3 to 8 μm.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

(Preparation of acrylic resin emulsion A-1)
While introducing nitrogen into a 3 liter reactor equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a reflux condenser, 700 parts of ion-exchanged water was mixed with Neoperex F-25 (an anionic emulsifier with a solid content of 25% manufactured by Kao Corporation). ) 40 parts, 5 parts of Neugen ET-170 (100% solid nonionic emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) dissolved, treated with membrane deoxygenator: Separel PF (manufactured by Dainippon Ink & Chemicals), and reacted I put it in the kettle. Stirring was started and the temperature was raised to 65 ° C.

  1 part of potassium persulfate was charged and the reaction temperature was kept at 65 to 67 ° C., and 180 parts of ion-exchanged water separately prepared, 33 parts of New Coal 707F (anion emulsifier with a solid content of 30% manufactured by Nippon Emulsifier Co., Ltd.) 485 parts, 425 parts of methyl methacrylate, 90 parts of methacrylic acid, and 2 parts of 3-methacryloxypropyltriethoxysilane were stirred and emulsified into a membrane-type deoxygenator: Separel PF-F (Dainippon Ink Chemical Co., Ltd.) While being deoxygenated by Kogyo Kogyo Co., Ltd.), it was dropped into the reaction kettle over 4 hours with a metering pump.

  After completion of dropping, the temperature was raised to 80 ° C., 0.5 part of t-butylperoxy-2-ethylhexanoate was added, and the mixture was further maintained at the same temperature for 3 hours and cooled to room temperature. The pH was adjusted to 6.5 using 5 parts of N, N-dimethylethanolamine and 25% aqueous ammonia, and ion exchange water was added to adjust the solid content to 36%. The obtained emulsion polymer had a solid content of 36% and a pH of 6.5. This is abbreviated as acrylic resin A-1.

(Preparation of acrylic resin emulsion A-2 to A-6)
In the same manner as in Preparation Example 1, acrylic resins A-2 to A-6 shown in Table 1 were prepared.

Example 1
To 100 parts of the acrylic resin A-1 (solid content: 36%, Tg: 30, methacrylic acid content: solid content ratio 9%, acid value: 59), 52 parts of ion-exchanged water is added to a dispersion stirrer. After stirring and mixing, the additives ((3), (4), (5)) and the colorant (6) were mixed at a mass ratio shown in Table 2. A glass container was dip-coated on the obtained aqueous coating agent and then dried at room temperature for 48 hours to obtain a sample of Example 1 having a dry film thickness of 5 μm.

(Examples 2-7, Comparative Examples 1-2)
In the same manner as in Example 1, an aqueous coating material was prepared with the composition shown in Table 2. Further, in the same manner as in Example 1, a glass container was dip coated on the obtained aqueous coating material, and then at room temperature. It dried for time and obtained the sample of Examples 2-7 and Comparative Examples 1 and 2 with a dry film thickness of 5 micrometers.

  In Table 1, Si-A represents 3-methacryloxypropyltriethoxysilane, Si-B represents 3-methacryloxypropyltrimethoxysilane, MAA represents methacrylic acid, and the content is% solid content. .

The additives and the like in Table 2 are as follows.
(2) Ion-exchanged water (3) SN deformer 777 (manufactured by San Nopco, defoamer)
(4) Dynol 604 (manufactured by Air Products, surfactant)
(5) Texanol (Eastman Chemical Co., Ltd., film-forming aid)

The colorants in Table 2 are as follows.
(6) Kayalon Polyester Dark Brown AS 200 (Nippon Kayaku Dye)
(7) Kayalon Polyester Dark Brown TS 200 (Nippon Kayaku Dye)
(8) IRUGASPERSE Brown RW (Dye made by Ciba Specialty Chemicals)
(9) Luconyl Red 2817 (BASF pigment)

  The following evaluation was implemented with respect to above-described Examples 1 to 7 samples and Comparative Examples 1 and 2. The evaluation results are shown in Table 3.

(water resistant)
The appearance after the glass container after coating and drying was immersed in water at 25 ° C. was observed and evaluated according to the following criteria.
(Double-circle): Even if a glass container is immersed in water for 1 week, there is no change in the external appearance.
○: Even if the glass container is immersed in water for 1 day, there is no change in the overall appearance.
X: When a glass container was immersed in water for 1 day, whitening, peeling, color fading, or floating occurred in the coating agent.

(Alkali peelability)
The appearance after immersing the glass container coated with 4% NaOH aqueous solution at 75 ° C. for 3 minutes was observed and evaluated according to the following criteria.
(Double-circle): The coating agent of the whole glass container has peeled off.
○: A part of the coating material of the glass container remains.
X: The coating agent of the glass container is not peeled off.

(Light shielding)
The coated glass container was cut into a size of 1 cm × 3 cm, and the transmittance at 450 to 500 nm was measured using a spectrophotometer UV / VIS-660 (manufactured by JASCO), and evaluated according to the following criteria.
○: The transmittance is 5% or less.
X: The transmittance is larger than 5%.

(Appearance design)
The coated glass container was exposed to sunlight, the appearance was observed, and the following criteria were evaluated.
○: The coating film is transparent and the painted part is not uncomfortable.
X: The coating film is not transparent and is blurred.

  As the above evaluation results show, the aqueous coating agent for glass containers of the present invention using a hydrophobic dye has a water-resistant coating film on the surface of the glass container, and the white blur characteristic of pigment systems. It also has an appearance design.

The glass container formed by coating the aqueous coating agent for glass containers of the present invention is excellent in alkali peelability, water resistance, light-shielding properties and appearance design, and can be used, for example, in beer bottles and drink glass bottles.

Claims (5)

An aqueous coating agent for glass containers, comprising an acrylic resin emulsion having film-forming properties and a hydrophobic dye having an absorption region at a wavelength in the ultraviolet to visible light region. An acrylic resin emulsion is an emulsion obtained by copolymerizing a (meth) acrylic acid monomer and a radical polymerizable monomer essentially comprising a silane coupling agent having a radical polymerizable unsaturated group, The methacrylic acid monomer is 1 to 20% by mass, and the radically polymerizable unsaturated group-containing silane coupling agent is 0.05 to 5% by mass with respect to 100 parts by mass of solid content. The aqueous coating agent for glass containers as described in 2. The aqueous coating agent for glass containers according to claim 1 or 2, wherein the silane coupling agent containing a radically polymerizable unsaturated group is a vinyl group-containing alkoxysilane and / or a (meth) acryloyl group-containing alkoxysilane. . A glass container obtained by coating the aqueous coating agent for a glass container according to any one of claims 1 to 3. The glass container according to claim 4, wherein the light transmittance at a wavelength of 500 nm transmitted through the glass container is 5% or less.