JP2003034767A - Ink and coating binder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ink and a coating binder having good pigment dispersibility, good compatibility with urethane resins, providing tough coating films, excellent in adhesive properties to plastic films and comprising environmental friendliness, thereby practically extremely effective as the ink and coating binder for various plastic films. SOLUTION: The ink or the coating binder essentially consists of acrylic copolymers obtained by copolymerizing monomer mixtures including (1) 40-98 wt.% of alkyl(meth)acrylates, (2) 1-40 wt.% of radical polymerizable monomers having a benzene ring, and (3) 1-20 wt.% of radically polymerizable monomers having a hydrophilic polar group and do not include any benzene ring.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can provide a coating film having good pigment dispersibility, toughness, and excellent adhesion to a plastic film. The present invention relates to a binder for ink and paint. 2. Description of the Related Art
As a binder for inks and paints to be printed or applied on polyester or polyolefin films,
Vinyl chloride resins and urethane resins have been used. A binder containing a vinyl chloride-based resin as a main component has good pigment dispersibility, generates less insoluble aggregates (scrap), and forms a tough coating film. However, there is a problem that adhesion to a plastic film is poor, and a toxic gas such as hydrogen chloride is generated at the time of combustion, which is not preferable from the viewpoint of environmental protection. A binder containing a urethane resin as a main component forms a tough coating film and has good adhesion to a plastic film. However, there is a disadvantage that the pigment dispersibility is poor and insoluble aggregates are generated during coating. Therefore, in recent years, attempts have been made to solve the problems of each of the resins by using a vinyl chloride resin and a urethane resin in combination. In view of environmental protection, use of vinyl chloride resin is not preferable. Therefore, development of a binder that does not have the above-mentioned disadvantages and does not contain a vinyl chloride resin is desired. The present invention has been made in order to meet the above-mentioned demands, and has good pigment dispersibility, good compatibility with urethane-based resins, low generation of insoluble aggregates during coating,
An object of the present invention is to provide a binder for inks and coatings that provides a tough coating film having excellent adhesion to a plastic film and also has environmental protection suitability. Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above object, and as a result, have found that alkyl (meth) acrylate (alkyl (meth)
Acrylate is a general term for alkyl acrylate and alkyl methacrylate. The same applies hereinafter. Acrylic monomers obtained by copolymerizing a monomer mixture containing a specific amount of a radical polymerizable monomer having a benzene ring and a radical polymerizable monomer not having a benzene ring having a hydrophilic polar group. The copolymer can improve the above problem as a binder for inks and coatings, has good pigment dispersibility, has good compatibility with urethane resins, can be compatible with a wide range of ratios, and It produces a coating film with little insoluble matter at the time of painting, which is tough and has excellent adhesion to plastic films, and also has environmental protection suitability, and is suitable as a binder for inks and coatings for various plastic films. The inventors have found that the present invention has been accomplished. Accordingly, the present invention provides (1) an alkyl (meth) acrylate of 40 to 98% by weight, (2) a radically polymerizable monomer having a benzene ring of 1 to 40% by weight, and (3) a hydrophilic polar group. Binders for inks or coatings comprising, as a main component, an acrylic copolymer obtained by copolymerizing a monomer mixture containing 1 to 20% by weight of a radical polymerizable monomer containing no benzene ring. I will provide a. Hereinafter, the present invention will be described in more detail. The acrylic copolymer, which is the main component of the ink and coating binder of the present invention, comprises a monomer mixture of the above-mentioned components (1) to (3) as a main raw material. Use as The alkyl (meth) acrylate as the component (1) has 1 to 18 carbon atoms, preferably 1 to 1 carbon atoms.
Alkyl (meth) acrylate having an alkyl group of from 10 to 10 is preferable, and specifically, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and pentyl (Meth) acrylate, hexyl (meth) acrylate, octyl (meth)
Examples thereof include acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate, and one of these can be used alone, or two or more can be used in combination. The amount of the alkyl (meth) acrylate is 40 to 98% by weight of the total monomers, preferably 55 to 95% by weight. If the amount is less than 40% by weight, the coating film becomes soft and the adhesion to the plastic film is reduced. If the amount is more than 98% by weight, the coating film becomes brittle and the compatibility with the urethane resin and the like is reduced. . The radical polymerizable monomer having a benzene ring as the component (2) is, for example, a compound having a vinylic double bond copolymerizable with the alkyl (meth) acrylate and containing a benzene ring. Benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-acryloyloxyethylphthalic acid, styrene, α-methylstyrene, Examples thereof include vinyltoluene, and of these, only one type can be used alone, or two or more types can be used in combination. The amount of the radical polymerizable monomer having a benzene ring is 1 to 40% by weight of the total monomer.
Preferably it is 2 to 35% by weight. If it is less than 1% by weight, the compatibility with the urethane-based resin or the like decreases, and if it exceeds 40% by weight, the viscosity of the ink or paint increases. The radically polymerizable monomer having no benzene ring and having a hydrophilic polar group as the component (3) includes, for example, a hydrophilic polar group such as a hydroxyl group, a carboxyl group, a sulfonic acid group, and a phosphoric acid group. Those having a vinylic double bond copolymerizable with the above alkyl (meth) acrylate are preferred. Here, the hydroxyl group-containing monomers include hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, and polyethylene. Polyalkylene glycol mono (meth) acrylates such as glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol polypropylene glycol mono (meth) acrylate, hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether and hydroxypropyl vinyl ether, and hydroxyethyl Mono (meth) allyl ether, hydroxypropyl mono (meth) allyl ether, hydroxybutyl mono (meth) a Dialkylene glycol mono (meta) such as hydroxyalkyl (meth) allyl ether such as butyl ether, 3-chloro-2-hydroxypropyl (meth) allyl ether, diethylene glycol mono (meth) allyl ether, and dipropylene glycol mono (meth) allyl ether. ) Allyl ether, glycerin mono (meth) allyl ether, vinyl alcohol, (meth)
Allyl alcohol and the like can be mentioned. In addition, it is preferable that the alkyl group and the alkylene group in the said hydroxyl-containing monomer are a C1-C5 lower alkyl group or an alkylene group. Further, vinyl alcohol can be produced by copolymerizing vinyl acetate and performing a saponification reaction with a caustic alkali in a solvent. Examples of the carboxyl group-containing monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid; unsaturated carboxylic anhydrides such as maleic anhydride and itaconic anhydride; Half esters of acids and the like. Examples of the sulfonic acid group-containing monomer include the following. Embedded image (Where M is a hydrogen atom or an alkali metal such as sodium or potassium, R is an alkyl group, preferably having 1 to 1 carbon atoms)
5 represents an alkyl group. Examples of the phosphoric acid group-containing monomer include mono [(meth) acryloyloxyethyl] acid phosphate and mono [(meth) acryloyloxypropyl]
Acid phosphate, mono [(meth) acryloyloxybutyl] acid phosphate, mono [(meth) acryloyloxyethoxyethyl] acid phosphate, mono [(meth) acryloyloxypolyoxyethylene glycol] acid phosphate, (meth) acryloyloxyethylmethyl Acid phosphate,
(Meth) acryloyloxyethyl butyl acid phosphate, (meth) acryloyloxypropyl ethyl acid phosphate, (meth) acryloyloxyethoxyethyl methyl acid phosphate, (meth) acryloyloxy polyoxyethylene glycol butyl acid phosphate, vinyl acid phosphate, and the like Alkali metal salts and the like. Among these hydrophilic polar groups, it is preferable to use a monomer containing a hydroxyl group and a carboxyl group. The radical polymerizable monomer containing no benzene ring having a hydrophilic polar group may be used alone or in combination of two or more. It is 1 to 20% by weight of the monomer, preferably 3 to 17% by weight. If the amount is less than 1% by weight, the dispersibility decreases, and if it exceeds 20% by weight, the viscosity of the ink or paint increases. In the present invention, other radical polymerizable monomers other than those described above can be copolymerized with the above monomers, if necessary. Specific examples of such other radical polymerizable monomers include vinyl acetate, vinyl propionate,
Acrylonitrile, ethylene, propylene, butylene,
Isobutylene, butadiene, glycidyl (meth) acrylate, glycidyl allyl ether, cyclohexyl (meth) acrylate, alkoxyalkyl (meth) acrylate such as methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and acetoacetoxyethyl (meth) acrylate , Acetoacetoxypropyl (meth) acrylate, acetoacetoxybutyl (meth) acrylate, acetoacetoxyisobutylene (meth) acrylate, and other acetoacetoxyalkyl (meth) acrylates, methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, n-
Examples thereof include alkyl vinyl ethers such as butyl vinyl ether, 2-ethylhexyl vinyl ether, n-octyl vinyl ether, lauryl vinyl ether, cetyl vinyl ether, and stearyl vinyl ether.
The compounding amount of these other monomers can be in a range that does not impair the effects of the present invention, and it is preferable to use them in a range of 10% by weight or less based on all the monomers. In addition, it is not preferable to copolymerize a nitrogen-containing monomer having radical polymerizability such as vinylpyrrolidone and vinylpyridine, because the viscosity of the ink or the coating material is increased or the compatibility with the urethane resin is significantly reduced. . In the present invention, the acrylic copolymer composed of a combination of the above units has a weight average molecular weight of 5,000 to 200,000, particularly 7,000 to 200,000.
It is preferably in the range of 140,000, and it is preferable to use each monomer in combination within this range.
If the weight average molecular weight is lower than 5,000, physical properties may deteriorate such as the coating film becoming brittle, and conversely, 200,00
If it exceeds 0, the viscosity of the ink or paint at a predetermined concentration becomes high, the workability becomes poor, and the handling may become difficult. For adjusting the molecular weight, a molecular weight modifier such as n-dodecyl mercaptan, thioglycol, trichloroethylene, sodium 2-chloroethanesulfonate, sodium P-chlorobenzenesulfonate can be used as necessary. The acrylic copolymer according to the present invention can be produced by a general solution polymerization method, precipitation polymerization method, suspension polymerization method, emulsion polymerization method or the like. In this case, the polymerization initiator used in the production of the copolymer includes persulfates and hydrogen peroxide such as ammonium persulfate, potassium persulfate and sodium persulfate; diisopropyl peroxydicarbonate, t-butyl Organic peroxide-based polymerization initiators such as hydroperoxide, benzoyl peroxide, cumene hydroperoxide and dibutyl peroxide; nitrogen-containing polymerization initiators such as azobisisobutyronitrile and azobisisovaleronitrile are exemplified. You. The amount of the polymerization initiator can be a usual amount. These polymerization initiators may be used alone, but they may be used together with sodium acid sulfite, Rongalit, L-
A reducing agent such as ascorbic acid, saccharide or amine may be used in combination, and in any case, polymerization can be carried out by a conventional method. In the case of solution polymerization, examples of the solvent include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate and butyl acetate. Examples of the solvent for precipitation polymerization include alcohols such as methanol, ethanol and isopropanol; and hydrocarbons such as hexane and pentane. Examples of the suspension stabilizer in the case of suspension polymerization include polyvinyl alcohol-based polymers such as polyvinyl alcohol and partially saponified polyvinyl acetate; cellulose derivatives such as methyl cellulose, hydroxypropyl cellulose and carboxymethyl cellulose; polyvinyl pyrrolidone; Examples include synthetic polymers such as acrylamide, maleic acid-styrene copolymer, and maleic acid-methyl vinyl ether copolymer; and natural polymers such as starch and gelatin. Further, as an emulsifier in the case of emulsion polymerization,
Anionic emulsifier such as alkyl or alkyl allyl sulfate, alkyl or alkyl allyl sulfonate, alkyl allyl sulfosuccinate; nonionic emulsifier such as polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene carboxylate And the like. In producing the acrylic copolymer according to the present invention, the above-mentioned monomer, polymerization initiator, suspension stabilizer,
An emulsifier or the like may be added to the polymerization system at the start of the polymerization and then polymerized, or these raw materials may be divided and added during the polymerization to perform the polymerization. In this case, the polymerization conditions can be appropriately adjusted, but it is desirable to carry out the polymerization at 40 to 80 ° C. After completion of the polymerization, the solution can be filtered, washed with water and dried in a usual manner. In the case of emulsion polymerization, a solution such as sodium chloride, calcium chloride or sodium sulfate can be obtained by a known salting-out method after the polymerization. The particles may be aggregated by adding an aqueous solution of an inorganic salt or by adding a water-soluble organic solvent or the like, followed by filtration, washing with water, and drying. The binder of the present invention contains the above-mentioned acrylic copolymer as a main component. If necessary, a urethane resin may be used in combination with this acrylic copolymer. In this case, the acrylic copolymer is excellent in compatibility with the urethane resin, and can be used in a wide range of ratios. Specifically, the urethane resin is used for 100 parts by weight of the acrylic copolymer. Is preferably 50 to 250 parts by weight, particularly preferably 100 to 200 parts by weight. When an ink or a paint is produced by using the binder mainly composed of the acrylic copolymer of the present invention, the amount of the binder mainly composed of the acrylic copolymer is added to the ink or the paint. Is 1 to 20% by weight, especially 3
It is preferable to use it so that it may be in the range of 15% by weight. Further, as the pigment used for the ink and the paint, an inorganic pigment such as carbon black, titanium white and red iron, phthalocyanine and an organic pigment such as an azo can be used. weight%
(0% by weight when transparent), more preferably 5 to 30% by weight. Furthermore, this ink or paint contains a plasticizer, wax, dispersant, wetting agent,
A thickener, a gelling agent, a thixotropic agent, an antifoaming agent and the like can be mixed in a usual amount. In this case, the binder containing the acrylic copolymer as a main component is an appropriate amount of methyl ethyl ketone,
It is preferable to use as a solution by dissolving in various solvents such as methyl isobutyl ketone, ethyl acetate, and toluene. In this solution, a pigment and, if necessary, a plasticizer, a wax, a dispersant, a wetting agent, and a thickener , Gelling agent, thixotropic agent,
A defoaming agent or the like can be dispersed or dissolved and can be produced by a conventionally known production machine. When an acrylic copolymer is prepared by an emulsion polymerization method, a pigment, a water-solubilizing agent, and a dispersing aid are added to the emulsion dispersion after polymerization without employing a known salting-out method after polymerization as described above. It is also possible to add an antifoaming agent or the like to prepare an ink or a paint. Further, when an acrylic copolymer is prepared by a solution polymerization method, it can be prepared in the same manner as described above. EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Parts and% in each example indicate parts by weight and% by weight, respectively. [Example 1] After nitrogen replacement in a polymerization vessel equipped with a stirrer, a condenser, a thermometer and a nitrogen gas inlet,
1500 parts of ethyl acetate, azobisisobutyronitrile 5
The temperature was raised to 65 ° C. while stirring under a nitrogen gas atmosphere. Next, 340 parts of methyl methacrylate, 300 parts of butyl methacrylate, 250 parts of benzyl methacrylate, 100 parts of hydroxyethyl methacrylate,
A mixture of 10 parts of acrylic acid and 0.1 part of dodecyl mercaptan was uniformly added to the above-mentioned polymerization vessel over 8 hours, and the reaction was further carried out at 75 ° C. for 4 hours. Was. Thereafter, 2,000 parts of methanol was added to precipitate a copolymer. The precipitated copolymer was filtered, washed twice with 1000 parts / time of methanol, then three times with 1000 parts / time of deionized water, filtered and dried to obtain a copolymer (hereinafter abbreviated as P1). ) 823 parts were obtained. In addition,
In Table 1, the charged amounts of the respective components are again described in terms of percentage by weight. The compatibility, pigment dispersibility, dispersion stability, and weight average molecular weight of the obtained copolymer were measured. The results are shown in Table 2. In addition, the measurement of each characteristic was performed as follows. A. Using a mixed solvent of compatible ethyl acetate / isopropyl alcohol = 1/1 (part), a 20% solution of the dry copolymer was prepared, and polyurethane resin [Sunplane IB-422 (trade name, manufactured by Sanyo Chemical Co., Ltd.) and CA-133 (trade name, manufactured by Toyo Morton Co., Ltd.)] at a ratio of 1: 1 (weight), stirred for 1 hour with a stirrer, applied and dried on a glass plate, The compatibility was visually evaluated in four stages from the degree of cloudiness. ◎: excellent, ○: good, Δ: acceptable, ×: not acceptable b. Pigment dispersibility (gloss) 20% solution of dry copolymer 1 prepared using a mixed solvent of ethyl acetate / isopropyl alcohol = 1/1 (part)
2.5 parts, titanium oxide (TIPAQUE, CR-90,
25 parts by Ishihara Sangyo Co., Ltd., 20 of polyurethane resin
% Solution (supra), 37.5 parts of ethyl acetate and 1 m
100 parts of mφ glass beads were placed in a 140 ml glass container, and dispersed for 1 hour with a paint conditioner to form a paint. The obtained paint was applied to a glass plate with a 3 mil doctor knife, and the gloss was compared with a standard glass plate using a gloss meter (manufactured by Murakami Color Materials Giken Co., Ltd.). c. Dispersion stability After the paint obtained in the above measurement was left at room temperature for 3 days, the state of separation of the pigment was visually observed. d. Weight average molecular weight: measured by GPC method. Examples 2 to 4, Comparative Examples 1 and 2
In the same manner as described above, copolymerization was carried out with the types of monomers and charged amounts (%) shown in Table 1, and precipitated, filtered and dried in the same manner to obtain copolymers (P2 to P4, P6 and P7). Was. Also,
Evaluation was performed in the same manner, and the results are shown in Table 2. Example 5 After nitrogen replacement in a polymerization vessel equipped with a stirrer, condenser, thermometer and nitrogen gas inlet,
1500 parts of deionized water, 0.35 sodium lauryl sulfate
Parts, dodecyl mercaptan 8 parts, potassium persulfate 10
And 3 parts of sodium carbonate, and heated to 70 ° C. while stirring under a nitrogen gas atmosphere. Next, 280 parts of methyl methacrylate, 150 parts of butyl methacrylate, 150 parts of butyl acrylate, 250 parts of benzyl methacrylate
, 150 parts of hydroxypropyl acrylate and 20 parts of methacrylic acid were uniformly added to the above-mentioned polymerization vessel over 8 hours, and the reaction was further carried out at 80 ° C. for 1 hour. I let it. Then, methanol 10
The copolymer was precipitated by adding 00 parts and 500 parts of 20% sodium sulfate. The precipitated copolymer was filtered, washed twice with 1000 parts of methanol / time, and then washed with 10 parts of deionized water.
After washing four times at 00 parts / time, filtering and drying, the copolymer (P
5) 720 parts were obtained. In Table 1, the charged amounts of the respective components are again described in terms of percentage by weight. Using the obtained copolymer, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2. [Table 1] [Table 2] The binder for inks and coatings of the present invention has good pigment dispersibility and good compatibility with urethane resins, and the resulting coating film is tough and can be applied to plastic films. It has excellent adhesion and environmental protection suitability, and is therefore extremely effective practically as a binder for inks and coatings for various plastic films.

Continuation of front page    F term (reference) 4J038 CC061 CC071 CC081 CG141                       CH031 CH041 CH081 DG031                       GA03 GA06 GA13 GA14 MA14                       NA25 NA27                 4J039 AB02 AD03 AD06 AD09 AD10                       AE04 BC04 BC18 BC22 BE01                       CA04 EA44 EA45

Claims (1)

Claims: (1) 40 to 98% by weight of an alkyl (meth) acrylate (2) 1 to 40% by weight of a radical polymerizable monomer having a benzene ring (3) A hydrophilic polar group Or paint comprising, as a main component, an acrylic copolymer obtained by copolymerizing a monomer mixture containing 1 to 20% by weight of a radical polymerizable monomer containing no benzene ring having For binders.