JP2005272761A - Method for producing aqueous resin dispersion and ultraviolet light-curing type aqueous resin composition by using aqueous resin dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous dispersion, enabling the use of hardly water soluble ultraviolet light polymerization initiator in water, and also satisfying the preservation stability as the aqueous dispersion and physical properties such as close adhesion, solvent resistance, etc., on making it a coated film. <P>SOLUTION: This method for producing the aqueous resin dispersion is characterized by making an ethylenically unsaturated monomer (M), a surfactant (S), an ultraviolet light polymerization initiator (P) and water as an emulsified state and performing an emulsion polymerization by using an emulsion polymerization initiator (I). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing an aqueous resin dispersion used in an aqueous ultraviolet curable resin composition, and the aqueous resin dispersion has a compound and / or a functional group that generates radicals by ultraviolet rays. The present invention also relates to an aqueous ultraviolet curable resin composition using the aqueous resin dispersion, and provides a cured film excellent in hardness, curing rate, crosslinking density, solvent resistance, and water resistance. , Glass, cloth, leather, paper, objects to be coated including plastics, ink binders, adhesives, coating agents, etc. applied to objects to be printed.

  In recent years, adhesives, coatings, printing industries, etc. have proposed water-based and solvent-free products as a means to solve air pollution caused by solvent-based products, fire hazard, occupational safety and health during work, etc. It is being advanced. In fact, water-based and solvent-free curable products are widely used in various fields, but some of them have problems with curing speed, crosslinking density, solvent resistance, water resistance, viscosity, etc., compared to solvent-based products. The current situation is limited to applications. In addition, the solventless type often uses a volatile monofunctional monomer having a small molecular weight in order to lower the viscosity, and there is a problem that the odor for that deteriorates the working environment. Therefore, there is an approach to solve this problem by giving a radiation curing performance to water-based products. Here, the radiation curing referred to in the present invention means curing by the energy of ionizing radiation such as an electron beam and ultraviolet rays. Among electron beam curing systems and ultraviolet curing systems, ultraviolet curing systems that have a small radiation device, are inexpensive, and do not necessarily need to be replaced with an inert gas during curing are generally widely used.

  The ultraviolet curable resin composition includes an ultraviolet polymerization initiator that initiates polymerization with ultraviolet rays and a monomer and / or oligomer that is polymerized by the ultraviolet polymerization initiator, but the ultraviolet polymerization starts in an aqueous system. When using an agent, there are the following problems.

  When mixing and adding an ultraviolet polymerization initiator to an aqueous ultraviolet curable resin composition, 1) a method using a water-soluble initiator, 2) when using a water-insoluble ultraviolet polymerization initiator, A method of mixing once dissolved and removing the solvent as necessary is employed. However, in the case of 1), since there is almost no water-soluble UV polymerization initiator on the market, the selection range is narrow, and existing UV polymerization initiators include hydrophilic groups such as polyethylene glycol, carboxyl groups, and quaternary ammonium salts. It takes labor and cost to introduce water into water. Moreover, when a hardened | cured material contacts with water, it may elute and it may cause the deterioration of the surface state of a coating film, or environmental pollution. In the case of 2), the mixing of organic solvents and the environmental load become problems. As a method for solving the above problem, the solvent is removed after mixing an ultraviolet polymerization initiator with a compound having two or more unsaturated double bonds in the molecule into a urethane resin having self-emulsifying ability synthesized in an organic solvent. Discloses a method for forming water-dispersed particles (see Patent Document 1). However, in this method, since an organic solvent is used as in the case of 2), an environmental load is inevitable.

On the other hand, water-dispersed acrylic resins obtained by emulsion polymerization are known to have particularly low environmental impact among water-based resins because they never use a solvent in the synthesis process. The disclosed invention is also disclosed. For example, there is a disclosure of an aqueous dispersion composed of a polymer containing a monomer having a cyclic imide group as a constituent and a compound having two or more (meth) acryloyl groups (see Patent Document 2). The monomer having a cyclic imide group has the ability to generate radicals by ultraviolet rays, but its ability is low compared with general ultraviolet polymerization initiators and a large amount is required. Since the absorption wavelength is narrow, there are limitations such as being unsuitable for compositions containing dyes, pigments, inorganic fine particles and the like that suppress the transmission of ultraviolet rays.
Japanese Patent Laid-Open No. 10-182863 Japanese Patent Laid-Open No. 2000-234044

  An object of the present invention is to make it possible to use a commercially available / distributed ultraviolet polymerization initiator in an aqueous ultraviolet curable resin composition without limitation without using any organic solvent.

  In the present invention, an ethylenically unsaturated monomer (M), a surfactant (S), an ultraviolet polymerization initiator (P), and water are emulsified and emulsified using the emulsion polymerization initiator (I). The present invention relates to a method for producing an aqueous resin dispersion characterized by performing polymerization.

  Moreover, this invention relates to the manufacturing method of the said aqueous resin dispersion whose average diameter of the non-aqueous phase of the emulsified state before emulsion polymerization is 10 micrometers or less.

  Moreover, this invention relates to the manufacturing method of the said aqueous resin dispersion in which an ultraviolet-ray polymerization initiator (P) contains the compound (PM) which has an ethylenically unsaturated double bond.

  Moreover, this invention relates to the aqueous resin dispersion (E) obtained by the said manufacturing method.

  Moreover, this invention relates to the ultraviolet curable aqueous resin composition containing the said aqueous resin dispersion (E) and the compound (X) which has an ethylenically unsaturated double bond.

  The present invention also relates to a cured product obtained by curing the aqueous resin composition with ultraviolet rays.

  According to the present invention, it is possible to use an ultraviolet polymerization initiator that is difficult to dissolve in water in an aqueous solution, and it is possible to satisfy the physical properties such as storage stability as an aqueous dispersion, adhesion when formed into a coating film, and solvent resistance. A dispersion could be provided.

  In the present invention, an ethylenically unsaturated monomer (M), a surfactant (S), an ultraviolet polymerization initiator (P), and water are emulsified and emulsified using the emulsion polymerization initiator (I). The aqueous resin dispersion obtained by carrying out the polymerization contains the ultraviolet polymerization initiator (P) in the water and exists in water, so that the ultraviolet polymerization initiator (P) is not soluble in water. It can be used for an aqueous ultraviolet curable resin composition.

  As the ethylenically unsaturated monomer (M) used in the present invention, a (meth) acrylic acid ester having an alkyl group having 1 to 18 carbon atoms is preferably used as a main component. Examples of the acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and n-hexyl. (Meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, etc., nonyl (meth) acrylate, isononyl (meth) Acrylate, decyl (meta Acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, isododecyl (meth) acrylate, tridecyl (meth) acrylate, isotridecyl (meth) acrylate.

The ethylenically unsaturated monomer (M) preferably contains a polar group-containing monomer, and examples of the polar group include a carboxyl group, a hydroxyl group, and an amide group. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, acrylic acid dimer, crotonic acid, itaconic acid, maleic acid and the like. Examples of the hydroxyl group-containing monomer include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, dihydroxy acrylate, and glycerol (meth) acrylate. Examples of the amide group-containing monomer include (meth) acrylamide, N-alkyl (meth) acrylamide, and N, N-dialkyl (meth) acrylamide.
Of these, the carboxyl group-containing monomer is preferably used in the range of 0.1 to 30 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer (M) from the viewpoint of polymerization stability.

  Moreover, the monomer which has a crosslinkable group can also be contained as a component of an ethylenically unsaturated monomer (M). Examples of the crosslinkable group include an epoxy group, an alkoxysilyl group, a methylol group, and an acetoacetyl group. In addition, examples of the monomer having a crosslinkable group also include a polyfunctional ethylenically unsaturated monomer having two or more ethylenically unsaturated double bonds.

  Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

  Examples of the alkoxysilyl group-containing monomer include γ- (meth) acryloxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meta ) Acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth) Acryloxypropyldimethylethoxysilane, γ- (meth) acryloxypropyltrichlorosilane, γ- (meth) acryloxypropylmethyldichlorosilane, γ- (meth) acryloxypropyldimethylchlorosilane, γ- (meth) acryloxypropyltri Propoxy , Γ- (meth) acryloxypropylmethyldipropoxysilane, γ- (meth) acryloxypropyltributoxysilane, γ- (meth) acryloxybutyltrimethoxysilane, γ- (meth) acryloxypentyltrimethoxy Silane, γ- (meth) acryloxyhexyltrimethoxysilane, γ- (meth) acryloxyhexyltriethoxysilane, γ- (meth) acryloxyoctyltrimethoxysilane, γ- (meth) acryloxydecyltrimethoxysilane, γ- (meth) acryloxydodecyltrimethoxysilane, γ- (meth) acryloxyoctadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripyropoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane , Vinylmethyldipropoxysilane and the like can be mentioned.

  Examples of the methylol group-containing monomer include N-methylol acrylamide and butoxy N-methylol acrylamide.

  Examples of the acetoacetyl group-containing monomer include diacetone (meth) acrylamide, 2- (acetoacetoxy) ethyl (meth) acrylate, and allyl acetoacetate.

  Polyfunctional ethylenically unsaturated monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) ) Acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) ) Acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (Meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, glycerin methacrylate acrylate, tris (meth) acryloyloxyphosphate, glycerin di (meth) acrylate, allyl (meth) acrylate diallyl phthalate, Examples include tetraallyloxyethane, divinylbenzene, and tri (meth) allyl isocyanurate.

  The ethylenically unsaturated monomer (M) exemplified above can be used in combination, and there is no limitation on the type and the ratio of the combination in accordance with the purpose of use. Here, the ethylenically unsaturated monomer (M) referred to in the present invention does not include a compound (PM) having an ultraviolet polymerization opening ability and having an ethylenically unsaturated double bond, which will be described later.

  The surfactant (S) used in the present invention is not particularly limited as long as it has a function capable of emulsifying each component in an aqueous medium, and any known one can be used without limitation. For example, an ionic or nonionic reactive surfactant having an ethylenically unsaturated double bond, an ionic or nonionic nonreactive surfactant having no ethylenically unsaturated double bond, etc. Used alone or in combination. Among these, in consideration of water resistance, it is preferable to use a reactive surfactant.

  Specific examples of the reactive surfactant include ADEKA rear soap SE-20N (anionic), ADEKA rear soap SE-10N (anionic), ADEKA rear soap NE-10 (nonionic), and ADEKA rear soap NE-. 20 (nonionic), ADEKA rear soap NE-30 (nonionic), ADEKA rear soap NE-40 (nonionic), ADEKA rear soap SDX-730 (anionic), ADEKA rear soap SDX-731 (anionic) [ Asahi Denka Co., Ltd.], Eleminol JS-2 (anionic), Eleminol RS-30 (anionic) [Sanyo Kasei Co., Ltd.], Latemul S-180A (anionic), Latemul S- 180 (anionic), Latemul PD-104 (anionic) [above, manufactured by Kao Corporation], Aqualon BC-05 (anionic), Aqualon BC-10 (anionic), Aqualon BC-20 (anionic), Aqualon KH-10 (anionic), Aqualon KH-20 (anionic), Aqualon HS-05 (anionic), Aqualon HS-10 ( Anionic), Aqualon HS-20 (Anionic), Aqualon RN-10 (Nonionic), Aqualon RN-20 (Nonionic), Aqualon RN-30 (Nonionic), Aqualon RN-50 (Nonionic), New Commercial products such as Frontier S-510 (anion) [manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], Phosfinol TX (anionic) [manufactured by Toho Chemical Industry Co., Ltd.], and the like.

  In the production method of the present invention, when the ethylenically unsaturated monomer (M) is 100 parts by weight, the amount of the surfactant (S) is preferably 0.5 to 5 parts by weight, more preferably 0.8 to 4 parts by weight, particularly preferably 1 to 3 parts by weight. If the surfactant (S) is less than 0.5 parts by weight, aggregates and the like are likely to be generated during the polymerization, and if it exceeds 5 parts by weight, the water resistance of the coating film may be undesirably lowered.

  The ultraviolet polymerization initiator (P) used in the present invention is not particularly limited as long as it has a function capable of initiating polymerization of an ethylenically unsaturated double bond by photoexcitation, and examples thereof include monocarbonyl compounds and dicarbonyls. Compounds, acetophenone compounds, benzoin ether compounds, acyl phosphine oxide compounds, aminocarbonyl compounds and the like can be used.

  Specific monocarbonyl compounds include benzophenone, 4-methyl-benzophenone, 2,4,6-trimethylbenzophenone, methyl-o-benzoylbenzoate, 4-phenylbenzophenone, 4 (4-methylphenylthio) phenyl-enetanone, 3,3'-dimethyl-4-methoxybenzophenone, 4- (1,3-acryloyl-1,4,7,10,13-pentaoxotridecyl) benzophenone, 3,3 ', 4,4'-tetra ( t-Butylperoxycarbonyl) benzophenone, 4-benzoyl-N, N, N-trimethylbenzenemethammonium chloride, 2-hydroxy-3- (4-benzoyl-phenoxy) -N, N, N-trimethyl-1-propanamine Hydrochloride, 4-benzoyl-NN-dimethyl-N- [2- (1-oxo-2-propenyloxyethyl) methammonium bromide, 2- / 4-iso-propylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothio Xanthone, 1-chloro-4-propoxythioxanthone, 2-hydroxy-3- (3,4-dimethyl-9-oxo-9H thioxanthone-2-iroxy) -N, N, N-trimethyl-1-propanamine hydrochloride Benzoylmethylene-3-methylnaphtho (1,2-d) thiazoline and the like.

  Dicarbonyl compounds include 1,7,7-trimethyl-bicyclo [2,1,1] heptane-2,3-dione, benzyl, 2-ethylanthraquinone, 9,10-phenanthrenequinone, methyl-α-oxobenzene Examples include acetate and 4-phenylbenzyl.

  Acetophenone compounds include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- ( 4-Isopropylphenyl) 2-hydroxy-di-2-methyl-1-phenylpropan-1-one, 1-hydroxy-cyclohexyl-phenylketone, 2-hydroxy-2-methyl-1-styrylpropan-1-one polymerization , Diethoxyacetophenone, dibutoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,2-diethoxy-1,2-diphenylethane-1-one, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholino-phenyl) butan-1-one, 1-phenyl-1,2- Propanedione-2- (o-ethoxycarbonyl) oxime, 3,6-bis (2-methyl-2-methyl) Horino - Puropanoniru) -9-butyl carbazole, and the like.

  Examples of the benzoin ether compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzoin normal butyl ether.

Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 4-n-propylphenyl-di (2,6-dichlorobenzoyl) phosphine oxide.
Examples of aminocarbonyl compounds include methyl-4- (dimethylamino) benzoate, ethyl-4- (dimethylamino) benzoate, 2-n butoxyethyl-4- (dimethylamino) benzoate, isoamyl-4- (dimethylamino) benzoate, 2- (Dimethylamino) ethyl benzoate, 4,4'-bis-4-dimethylaminobenzophenone, 4,4'-bis-4-diethylaminobenzophenone, 2,5'-bis- (4-diethylaminobenzal) cyclopenta Non etc. are mentioned. These exemplified compounds may be used alone or in combination.
The ultraviolet polymerization initiator (P) exemplified above is a resin (including both a resin having a radical polymerization property and a resin having no radical polymerization property) used in the ultraviolet curable resin composition, and a radical polymerization property. Reacts only partially with monomers having Therefore, the ultraviolet polymerization initiator (P) exemplified above remains unreacted or becomes a decomposition product decomposed by a photoreaction, and all remains as a residue in the final cured film. The presence of the residue may cause a problem, for example, as shown in the following (1) to (4).

(1) Residues partially volatilize and cause odor of printing / coating sites or printed / coated materials. (2) In applications where transparency is required, such as films and overcoat varnishes, the residue causes color changes that occur over time, such as yellowing. (3) In the process of stacking and winding up printed materials / coating materials, the residue exudes / transfers from the printed surface or coated surface to other surfaces, and the exuded / transferred material is the inclusion. Touching etc. has an unfavorable influence on the inclusion (for example, in the case of a beverage, the taste changes). (4) When used in electronic materials, the residue diffuses into the surrounding medium, causing electrical trouble in addition to problems such as yellowing and odor.

  In the present invention, in the usage method and application in which such a problem is concerned, the compound (PM) described below as the ultraviolet polymerization initiator (P) is used in an amount of 30% by weight or more of the entire ultraviolet polymerization initiator (P). It is preferably 50% by weight or more, more preferably 80% by weight or more. If it is less than 30% by weight, the effect of suppressing the above problems (1) to (4) is thin. As the compound (PM), when the residue obtained by removing x hydrogen atoms from the hydrogen atoms present in the ultraviolet polymerization initiator (P) exemplified above is used as the functional group <p>, the compound (PM) may be present. Absent. In the compound (PM), two or more different functional groups <p> and two or more different functional groups having different ethylenically unsaturated double bonds may exist in one molecule. In the ultraviolet curable aqueous resin composition of the present invention, when all of the ultraviolet polymerization initiator (P) is a compound (PM), the ethylenically unsaturated double bond present in the compound (PM) contributes to radical polymerization. Therefore, the above problems (1) to (4) are preferably suppressed.

  In the production method of the present invention, when the ethylenically unsaturated monomer (M) is 100 parts by weight, the amount of the ultraviolet polymerization initiator (P) is preferably 1 to 200 parts by weight, more preferably 5 parts. -100 parts by weight, most preferably 10-50 parts by weight. When the amount is less than 1 part by weight, the effect of the ultraviolet polymerization initiator may be weak, and when it exceeds 200 parts by weight, the polymerization stability may be deteriorated.

  The emulsion polymerization initiator (I) used in the present invention is not particularly limited as long as it generates radicals by heat or a reducing agent, and any water-soluble or oil-soluble one can be used. . It is a compound in which a specific functional group <p> and a functional group having x ethylenically unsaturated double bonds are connected by a covalent bond. At this time, what is the bond between the ethylenically unsaturated double bond and the functional group <p> is alkyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, p-methane hydroperoxide. Oxide, isobutyl peroxide, laurolyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, Di-t-butyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, di-isobutyl peroxide Oxy Organic peroxides such as carbonate, di-2-ethylhexylperoxydicarbonate, t-butylperoxyisobutyrate, azobisisobutyronitrile, dimethylazodiisobutyrate, 2,2-azobis (2,4- Dimethylvaleronitrile), 2,2-azobis (2-methylbutyronitrile), potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, ammonium 4,4′-azobis-4-cyanovaleric acid ( Amine) salt, 2,2′-azobis (2-methylamidooxime) dihydrochloride, 2,2′-azobis (2-methylbutanamidoxime) dihydrochloride tetrahydrate, 2,2′-azobis {2-methyl -N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] -propio Amide}, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], various redox catalysts (in this case, as the oxidizing agent, ammonium persulfate, potassium persulfate, hydrogen peroxide, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide and the like, and sodium sulfite, acidic sodium sulfite, Rongalite, ascorbic acid and the like are used as the reducing agent. . Of these, water-soluble ones are preferably used. Here, the emulsion polymerization initiator (I) referred to in the present invention does not include the ultraviolet polymerization initiator (P) that initiates polymerization by ultraviolet rays.

  In the production method of the present invention, when the ethylenically unsaturated monomer (M) is 100 parts by weight, the amount of the emulsion polymerization initiator (I) is preferably 0.01 to 10 parts by weight, more preferably Is 0.05 to 5 parts by weight. If the polymerization initiator is less than 0.01 parts by weight, the polymerization rate may be slow, and if it exceeds 10 parts by weight, the molecular weight of the resin may be lowered and the cured product may have poor resistance.

  In the production method of the present invention, the ethylenically unsaturated monomer (M), the surfactant (S), the ultraviolet polymerization initiator (P), and water are mixed and stirred to obtain an emulsified state. At this time, the emulsion polymerization initiator (I) may or may not coexist. The ultraviolet polymerization initiator (P) is preferably used by dissolving in advance in the ethylenically unsaturated monomer (M). Moreover, when using a water-insoluble thing as emulsion polymerization initiator (I), it is preferable to melt | dissolve in an ethylenically unsaturated monomer (M) previously.

  The emulsified state is preferably an O / W type in which a non-aqueous phase is dispersed in a continuous phase of water. At this time, the cumulative volume average diameter of the non-aqueous phase droplets may be 100 μm or less. However, if the generation of aggregates or precipitation of the ultraviolet polymerization initiator (P) occurs during the polymerization, it is forced to apply a high share. The cumulative volume average diameter of the non-aqueous phase droplets is preferably 10 μm or less by stirring, more preferably 5 μm or less, and most preferably 3 μm or less. In order to reduce the cumulative volume average diameter of non-aqueous phase droplets to 10 μm or less, a commercially available emulsifier can be used. A rotary emulsifier, a colloid mill emulsifier, a high-pressure homogenizer emulsifier, and an ultrasonic treatment emulsifier. For example, a forced emulsifier can be used.

  Here, the cumulative volume average diameter refers to a value that can be measured using, for example, a master sizer 2000 manufactured by Malvern, which is a laser diffraction particle size distribution measuring apparatus.

  The amount of water used in the emulsified state is based on 100 parts by weight of the total amount of ethylenically unsaturated monomer (M), surfactant (S), ultraviolet polymerization initiator (P), and water. The amount is preferably 25 parts by weight or more and 90 parts by weight or less, and more preferably 30 to 50 parts by weight. If the amount of water used is less than 25 parts by weight, an O / W type emulsion may not be formed, and even if it can be formed, the viscosity becomes high and workability may deteriorate. If it exceeds 90 parts by weight, the concentration of the later aqueous resin dispersion (E) may decrease and productivity may deteriorate.

  After the emulsion state, the polymerization is carried out in the presence of the emulsion polymerization initiator (I). ) Polymerize by heating the whole amount of the emulsion as it is. 2.) Raise the temperature of a part of the emulsion to start the polymerization, and drop or add the remaining emulsion dropwise to continue the polymerization. ) After charging the reaction can with water and, if necessary, the surfactant (S) and raising the temperature, the whole emulsion is dropped or added in portions to polymerize, and the emulsion polymerization initiator (I) is reacted. Either or both of the can and the dropping can may be charged in an arbitrary ratio, or only the initiator may be dropped or added separately.

  Although it does not specifically limit as polymerization conditions in the said polymerization method, For example, 1. ) Is usually in the temperature range of about 40 to 100 ° C., and the reaction is carried out for about 1 to 8 hours after the start of temperature increase. 2. In the method of), 1 to 50% by weight of the emulsion is polymerized at 40 to 90 ° C. for 0.1 to 4 hours, and then the remaining emulsion is added dropwise or dividedly over about 1 to 5 hours. Aging is carried out at temperature for about 1 to 3 hours. 3. ), Water is charged so as to be 5 to 100% by weight of the emulsion, the temperature is raised to 40 to 90 ° C., the emulsion is added dropwise or dividedly over 2 to 5 hours, and then at the same temperature. Examples include a method of aging for 1 to 3 hours.

  The total amount of water in the polymerization method is preferably such that the solid content after polymerization is 10% by weight or more and 75% by weight or less. If it is less than 10% by weight, the productivity may deteriorate, and if it exceeds 75% by weight, a stable aqueous resin dispersion (E) may not be obtained.

  Moreover, when performing emulsion polymerization, in order to suppress the radical generation | occurrence | production from the ultraviolet-ray polymerization initiator (P), it is preferable that the reaction can and dripping can to be used do not receive an ultraviolet-ray.

  The aqueous resin dispersion (E) obtained by the production method of the present invention described above can be used as an ultraviolet curable aqueous resin composition by adding the compound (X) having an ethylenically unsaturated double bond. Specific examples of the compound (X) having an ethylenically unsaturated double bond include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and isopropyl (meth). Acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, Stearyl (meth) acrylate, lauryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate Phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, etc.

Alkoxypolyalkylene glycol (meth) acrylates such as methoxypolypropylene glycol (meth) acrylate and ethoxypolyethylene glycol (meth) acrylate;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, glycerol (meth) acrylate, polyethylene glycol (meth) Hydroxyl-containing (meth) acrylates such as acrylate and polypropylene glycol (meth) acrylate,
(Meth) acrylamide, and N-substituted types such as N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, diacetone (meth) acrylamide, acryloylmorpholine (meta ) Acrylamides,

Amino group-containing (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate;
Nitriles such as (meth) acrylonitrile, styrenes such as styrene and α-methylstyrene,
Vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, and fatty acid vinyls such as vinyl acetate and vinyl propionate;

  Also, alkylene glycol di (meth) acrylates such as 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, etc. Glycerin propylene oxide modified tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, trimethylolpropane propylene oxide modified tri (meth) acrylate , Isocyanuric acid ethylene oxide modified tri (meth) acrylate, isocyanuric acid ethylene oxide modified ε-caprolactone modified tri (meth) acrylate, 1,3,5-triacryloylhexahydro-s-triazine, pentaerythritol tri (Meta Acrylate - DOO, dipentaerythritol - Rutori (meth) acrylate - Totoripuropione - trifunctional (meth) such as bets acrylate - DOO acids. Pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate monopropionate, dipentaerythritol hexa (meth) acrylate, tetramethylol methanetetra (meth) acrylate And polyfunctional (meth) acrylates such as oligoester tetra (meth) acrylate and tris ((meth) acryloyloxy) phosphate.

  Further, in addition to the above-mentioned compounds, polyester (meth) acrylate, polyurethane (meth) acrylate, epoxy (meth) acrylate, (meth) acrylated maleic acid-modified polybutadiene and the like can be mentioned.

  Polyester (meth) acrylate is obtained by polycondensation of a polybasic acid and a polyhydric alcohol to obtain a polyester having a hydroxyl group or a carboxyl group, and then the hydroxyl group in the polyester and (meth) acrylic acid, Esterification with an unsaturated aliphatic polybasic acid such as maleic acid, or a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate in the polyester It can be obtained by esterification with (meth) acrylate having. Alternatively, it can also be obtained by reacting an acid anhydride, glycidyl (meth) acrylate and a compound having at least one hydroxyl group.

  A polyurethane (meth) acrylate is obtained by reacting a compound having at least two or more isocyanate groups in a molecule with a (meth) acrylate having a hydroxyl group, or at least two or more isocyanate groups in a molecule. And a polyhydric alcohol to obtain a urethane prepolymer having at least two isocyanate groups in the molecule, and then a (meth) acrylate having a hydroxyl group-containing urethane prepolymer with an isocyanate group-containing urethane prepolymer. -It can be obtained by reacting with

Epoxy (meth) acrylate is synthesized by a reaction between an epoxy group and acrylic acid or methacrylic acid, and includes a glycidyl compound, an alicyclic epoxy resin, or a novolac epoxy resin and acrylic acid or methacrylic acid. What reacts is mentioned.
The (meth) acrylated maleic acid-modified polybutadiene is obtained by adding maleic anhydride to a double bond in polybutadiene, and then a portion derived from maleic anhydride in the maleated polybutadiene and 2-hydroxyethyl (meth) acrylate. It can be obtained by reacting with a (meth) acrylate having a hydroxyl group such as.

  Here, (meth) acrylate means acrylate or methacrylate, (meth) acrylamide means acrylamide or methacrylamide, and (meth) acrylonitrile means acrylonitrile or methacrylonitrile.

  Among the compounds (X) having an ethylenically unsaturated double bond exemplified above, preferably a (meth) acryloyl group having a molecular weight of 2000 or less, a compound having a vinyl group, and N-substituted (meth) acrylamides, Preferred are compounds having an acryloyl group and N-substituted acrylamides, and most preferred are compounds having a bifunctional or higher acryloyl group.

  In addition, the ultraviolet curable aqueous resin composition obtained in the present invention includes, as an optional component, a solvent, a pigment, a dye, an antioxidant, a polymerization inhibitor, a leveling agent, a humectant, and a viscosity adjustment as long as the purpose is not impaired. Agents, preservatives, antibacterial agents, finely divided silica, plasticizers, surfactants, polymer emulsions and the like can be added.

  The ultraviolet curable aqueous resin composition of the present invention can be applied to objects to be coated and objects to be printed including wood, metal, glass, cloth, leather, paper, and plastic.

  Inks, paints, and adhesives containing the ultraviolet curable aqueous resin composition of the present invention include brush painting, spray painting, flow coating, curtain coating, dip coating, vacuum coating, -Coating, painting, and printing such as rucoat, river coat, gravure printing, flexographic printing, screen printing, and ink jet printing are possible.

  The ultraviolet curable aqueous resin composition of the present invention can be used as various adhesives including ink binders such as paints, gravure printing inks, flexographic printing inks and inkjet printing inks, and laminating adhesives.

  The ultraviolet curable aqueous resin composition of the present invention can be cured using a known ultraviolet irradiation device. As an ultraviolet irradiation device, a light source that normally contains light in the range of 200 to 500 nm, such as a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a gallium lamp, a xenon lamp, a carbon arc lamp, or the like is used. it can. The accumulated amount of ultraviolet light is not limited because the required minimum accumulated amount of light depends on the application, film thickness, presence / absence of a colorant, and the type and amount of the photopolymerization initiator. When curing by ultraviolet rays, although not particularly necessary, the oxygen concentration may be lower than that of air using an inert gas such as nitrogen.

In addition to ultraviolet rays, it is possible to use heat by infrared rays, far infrared rays, hot air, high-frequency heating or the like.
After application of the ultraviolet curable aqueous resin composition obtained in the present invention, it may be subjected to radiation curing after natural or forced drying, or may be naturally or forcedly dried after being subjected to radiation curing following coating. It doesn't matter.

  Hereinafter, the present invention will be specifically described with reference to examples. In the examples, “%” and “part” mean weight basis unless otherwise specified. Moreover, the particle diameter described in the Example shows the cumulative volume average diameter measured with the master sizer 2000 by Malvern.

Example 1: 49 parts of n-butyl acrylate, 49 parts of methyl methacrylate and 2 parts of acrylic acid were used as the ethylenically unsaturated monomer (M), and 2-methyl-1 was used as the ultraviolet polymerization initiator (P). -[4- (Methylthio) phenyl] -2-morpholinopropan-1-one (manufactured by Ciba Specialty Chemicals: Irgacure 907) and 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd .: Kayacure DETX-S) ) 6 parts were dissolved in advance. Thereto, 1.0 part of Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) as a surfactant (S) and 70 parts of water were added and stirred at 300 rpm for 10 minutes with a stirrer equipped with a screw type stirring blade. And emulsified. The particle size of the non-aqueous phase at this time was 40 μm.
In a separate container, 0.3 part of ammonium persulfate as an emulsion polymerization initiator (I) was dissolved in 5.7 parts of water to prepare an emulsion polymerization initiator (I) aqueous solution. In another container, 0.15 part of sodium isoascorbate was dissolved in 14.85 parts of water as a reducing agent to prepare an aqueous reducing agent solution.
Next, 100 parts of water is added to a reaction can equipped with a nitrogen introduction tube, a condenser, a stirring blade, a thermometer, a first dropping can, a second dropping can, and a third dropping can. Nitrogen was introduced while charging and stirring. 191 parts of the emulsion is charged in the first dropping can, 3 parts of the aqueous emulsion polymerization initiator (I) solution is charged in the second dropping can, and 7.5 parts of the reducing agent aqueous solution is charged in the third dropping can. It is. When the reaction can was heated and the internal temperature reached 60 ° C., 3 parts of the emulsion polymerization initiator (I) aqueous solution was put into the reaction can, and after 5 minutes, the first, second and third dripping cans were added. The liquid charged in was dropped into the reaction can at a constant rate over 2 hours. After completion of dropping, 7.5 parts of the reducing agent aqueous solution was further charged into a third dropping can and dropped into the reaction can at a constant rate over 1 hour. Thereafter, stirring was continued for 1 hour at 60 ° C. to complete the polymerization. The solid content rate of the obtained aqueous resin dispersion (E-1) was 40.5%. The particle size was 102 nm. Further, it was confirmed that some aggregates adhered to the reactor and the stirring blade used for the polymerization.

  Example 2: In Example 1, when making an emulsified state, the same operation was performed except that the emulsified state was obtained by stirring for 10 minutes at 12000 rpm with a homomixer instead of a stirrer equipped with a screw type stirring blade. The particle size of the non-aqueous phase of the emulsion at this time was 2.5 μm. Moreover, the solid content rate of the finally obtained aqueous resin dispersion (E-2) was 40.2%. The particle size was 210 nm. Moreover, there was no adhesion of aggregates to the reactor and the stirring blade used for the polymerization.

  Example 3: In Example 1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (manufactured by Ciba Specialty Chemicals: Irgacure 907) was used as the ultraviolet polymerization initiator (P). 24 parts and 6 parts of 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd .: Kayacure DETX-S) are used in a total of 30 parts. Instead, an acryloyl group is added to benzophenone as a compound (PM). 30 parts of bound compound (Evekril P-36: manufactured by Daicel UCB) was used, and when emulsified, the mixture was stirred for 10 minutes at 12000 rpm with a homomixer instead of a stirrer with a screw-type stirring blade, and emulsified. All operations were the same except for the above. The particle size of the non-aqueous phase of the emulsion at this time was 4.0 μm. Moreover, the solid content rate of the finally obtained aqueous resin dispersion (E-3) was 40.8%. The particle size was 150 nm. Moreover, there was no adhesion of aggregates to the reactor and the stirring blade used for the polymerization.

Comparative Example 1: 63.7 parts of n-butyl acrylate, 63.7 parts of methyl methacrylate, and 2.6 parts of acrylic acid were mixed, and Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) as a surfactant (S). (Product made) 1.0 part and 70 parts of water were added and it stirred at 300 rpm with the screw type stirring blade for 10 minutes, and was made into the emulsified state. The particle size of the non-aqueous phase at this time was 50 μm.
In a separate container, 0.3 part of ammonium persulfate as an emulsion polymerization initiator (I) was dissolved in 5.7 parts of water to prepare an emulsion polymerization initiator (I) aqueous solution. In another container, 0.15 part of sodium isoascorbate was dissolved in 14.85 parts of water as a reducing agent to prepare an aqueous reducing agent solution.
Next, 100 parts of water is added to a reaction can equipped with a nitrogen introduction tube, a condenser, a stirring blade, a thermometer, a first dropping can, a second dropping can, and a third dropping can. Nitrogen was introduced while charging and stirring. 191 parts of the emulsion is charged in the first dropping can, 3 parts of the aqueous emulsion polymerization initiator (I) solution is charged in the second dropping can, and 7.5 parts of the reducing agent aqueous solution is charged in the third dropping can. It is. When the reaction can was heated and the internal temperature reached 60 ° C., 3 parts of the emulsion polymerization initiator (I) aqueous solution was put into the reaction can, and after 5 minutes, the first, second and third dripping cans were added. The solution charged in was dripped at a constant rate into the reaction can over 2 hours. After completion of dropping, 7.5 parts of the reducing agent aqueous solution was further charged into a third dropping can and dropped into the reaction can at a constant rate over 1 hour. Thereafter, stirring was continued for 1 hour at 60 ° C. to complete the polymerization. The solid content rate of the obtained aqueous resin dispersion (N-1) was 40.8%. The particle size was 98 nm. Moreover, there was no adhesion of aggregates to the reactor and the stirring blade used for the polymerization.

  Comparative Example 2: 45 parts of water was added to 250 parts of the aqueous resin dispersion (N-1) obtained in Comparative Example 1, and heated to 90 ° C. 24 Methyl-2- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (manufactured by Ciba Specialty Chemicals: Irgacure 907) was used as an ultraviolet polymerization initiator (P) while stirring the mixture. Parts and 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd .: Kayacure DETX-S) were mixed and stirred at 90 ° C. for 24 hours with an aqueous resin dispersion having a solid content of 40.2% ( N-2) was obtained.

  Comparative Example 3: 45 parts of water was added to 250 parts of the aqueous resin dispersion (N-1) obtained in Comparative Example 1, and heated to 50 ° C. 30 parts of a compound (Evecryl P-36: manufactured by Daicel UCB) having acryloyl group bonded to benzophenone was mixed as a compound (PM) and stirred for 24 hours at 60 ° C. An aqueous resin dispersion (N-3) having a rate of 40.3% was obtained.

(Storage stability test of aqueous resin dispersion)
The aqueous resin dispersions obtained in Examples 1 to 3 and Comparative Examples 2 and 3 were placed in a sample bottle, and after repeating a cycle of 24 hours at 40 ° C. for 24 hours and 5 ° C. twice, It was confirmed that there was no precipitate. When there was a precipitate, it was collected and confirmed by infrared absorption spectrum to perform qualification. The results are shown in Table 1.

  The Examples and Comparative Examples shown in Table 1 contain 23% of the ultraviolet polymerization initiator (P) or compound (PM) in the solid content. As is clear from the examples, the aqueous resin dispersion (E) obtained by the production method of the present invention was able to allow the ultraviolet polymerization initiator (P) to exist in water with good storage stability. On the other hand, in the comparative example in which an aqueous resin dispersion not containing the ultraviolet polymerization initiator (P) was produced and then the ultraviolet polymerization initiator (P) was included in the aqueous resin dispersion, all were aqueous. Storage stability was poor because it was not absorbed by the resin dispersion, or even though it was absorbed, it exudes during storage.

Examples 4 to 6: The following operations were performed to prepare a transparent coating film and test it.
100 parts of each aqueous resin dispersion obtained in Examples 1 to 3 was taken, neutralized to pH 8 with triethanolamine subjected to the above storage stability test, and then stirred with a homomixer. To this place, 20 parts of trimethylolpropane ethylene oxide-modified triacrylate (manufactured by Toagosei Co., Ltd .: Aronix M-350), 20 parts of polyethylene glycol diacrylate (9EGA), and 1 part of a leveling agent are added in this order to form an ultraviolet curable aqueous solution. A resin composition was obtained.

This ultraviolet curable aqueous resin composition was coated on a PET film having been subjected to corona treatment having a thickness of 50 μm with a # 4 bar coater and dried at 60 ° C. for 30 seconds. This coating film was irradiated with ultraviolet rays having a power of 120 W / cm and an integrated light amount of 150 mJ / cm ² with a belt conveyor type ultraviolet irradiation device (UVC-2534 metal halide lamp type manufactured by USHIO INC.), And the following tests were performed.

(Adhesion test)
Cellophane tape (manufactured by Nichiban) was affixed to the coating film, then peeled off and observed for removal of the coating film.
○ ・ ・ ・ No peeling at all × ・ ・ ・ Partial peeling

(Solvent resistance)
A cotton swab was soaked with ethanol, and the surface of the cured coating film was rubbed up to 50 times.
Number: Number of round trips until the ground is exposed.

Example 8: A black coating film was prepared by performing the following operations and tested.
100 parts of “Printex 55” (manufactured by Degussa), water; 900 ml of ion-exchanged water were stirred with a homomixer to obtain a dispersion having a pigment concentration of 10% by weight. A 1000 ml four-necked flask was equipped with a stirring blade and a reflux condenser, and 125 parts of carbon black dispersion prepared by the above method, 250 parts of 60% nitric acid, and 125 parts of ion-exchanged water were charged at about 110 ° C. with stirring. The mixture was subjected to an oxidation treatment reaction under reflux for 5 hours and then washed with water. Furthermore, after removing residual ions with a reverse osmosis membrane, the pH was adjusted to 9 to 10 with an aqueous caustic soda solution to obtain an aqueous carbon black dispersion having a pigment content of about 20% and an average particle size of about 100 nm.

The aqueous resin dispersion obtained in Example 1 was taken, neutralized with triethanolamine to pH 8, and then stirred with a homomixer. Trimethylolpropane ethylene oxide-modified triacrylate (Toago) Synthesized Co., Ltd .: Aronix M-350 (20 parts) and polyethylene glycol diacrylate (9EGA) (20 parts) were added and stirred well. Then, 150 parts of the carbon black aqueous dispersion was mixed to obtain an ultraviolet curable aqueous resin composition. It was.
This ultraviolet curable aqueous resin composition was coated on a PET film having been subjected to corona treatment having a thickness of 50 μm with a # 4 bar coater and dried at 60 ° C. for 30 seconds. This coating film was irradiated with ultraviolet rays having a power of 120 W / cm and an integrated light quantity of 500 mJ / cm ² with a belt conveyor type ultraviolet irradiation device (UVC-2534 metal halide lamp type manufactured by Ushio Electric Co., Ltd.). A test and a solvent resistance test were conducted. The results are shown in Table 2.

  As is apparent from Table 2, the ultraviolet curable aqueous resin composition containing the aqueous resin dispersion (E) obtained from the production method of the present invention gives a coating film with good adhesion and solvent resistance. It was confirmed that the ultraviolet polymerization initiator (P) and / or the ultraviolet polymerization functional group <p> present in the aqueous resin dispersion (E) of the invention worked effectively. Furthermore, it is known that when benzophenone is usually used as an ultraviolet polymerization initiator, benzaldehyde is generated as a by-product and an unpleasant odor is generated. In Example 6, a compound (PM) having a benzophenone skeleton is used. Despite being done, the odor was weak.

Claims (6)

The emulsion polymerization is performed using the emulsion polymerization initiator (I) in an emulsion state of the ethylenically unsaturated monomer (M), the surfactant (S), the ultraviolet polymerization initiator (P), and water. A method for producing an aqueous resin dispersion characterized by the above. The method for producing an aqueous resin dispersion according to claim 1, wherein the average diameter of the non-aqueous phase in an emulsified state before emulsion polymerization is 10 µm or less. The method for producing an aqueous resin dispersion according to claim 1 or 2, wherein the ultraviolet polymerization initiator (P) contains a compound (PM) having an ethylenically unsaturated double bond. An aqueous resin dispersion (E) obtained by the production method according to claim 1. An ultraviolet curable aqueous resin composition comprising the aqueous resin dispersion (E) according to claim 4 and a compound (X) having an ethylenically unsaturated double bond. A cured product obtained by curing the aqueous resin composition of claim 5 with ultraviolet rays.