JP5669345B2 - Composition for flat printing liquid and flat printing liquid using the same - Google Patents

Description

  The present invention relates to a flat printing liquid, for example, a composition used for an overprint varnish for flat printing (hereinafter sometimes abbreviated as OP varnish) and a flat printing ink, and a flat printing liquid using the same.

  Lithographic printing is used extensively in a wide range of fields, including commercial printing such as posters, catalogs, calendars, flyers, packaging printing, publication printing, and newspaper printing. In lithographic printing, an oleophilic lithographic printing liquid and water are alternately applied to a plate surface (usually referred to as a flat plate) composed of an oleophilic image area and a hydrophilic non-image area, which has almost no difference in height. In this method, printing is performed while giving to the printer.

  The flat printing liquid contains a resin, a vegetable oil, a high boiling point petroleum solvent, and, in some cases, a so-called vehicle containing a plasticizer and a wax. In general, the vehicle absorbs oxygen in the air and is dried by the progress of oxidative polymerization of the resin in the vehicle (oxidation polymerization dry type vehicle). The vehicle is combined with an organic acid such as octyl acid to promote oxidative polymerization. Generally, a metal salt dryer with a transition metal such as cobalt or manganese is blended. Further, in some cases, it is possible to add a heat drying method to the vehicle.

  However, even if a metal salt dryer is blended or a heat drying method is added, drying of the printed surface usually takes a long time of several hours. The work efficiency was extremely poor because it was difficult to work. Also, since it takes time to dry, when the printed material is placed on top of each other, the back side of the printing surface is soiled with printing ink, so-called “set-off”, and in some cases, “blocking” occurs on the back side and the front side of the printing surface. Problems can occur.

  In particular, recently, there is a tendency to reduce the ratio of high-boiling petroleum solvents in the vehicle due to environmental problems, so as the amount of drying oil / semi-drying oil used as vegetable oil increases, the solubility of the resin used increases and the solvent increases. Since the release is slow and the penetration into the paper is slow, the drying property is lowered, and the problems of “set-off” and “blocking” are more likely to occur.

  As these prevention methods, there is a so-called powder spraying method in which an anti-set-off agent such as silicone-treated processed starch is kneaded in the vehicle in advance, or fine powder such as starch is sprayed on the printing surface immediately after printing. It is taken. Although the powder spraying method is effective, the powder is scattered and floating around the printing press, which is a problem in terms of environmental hygiene. Further, when fine powder adheres to the printing surface, there is a problem that the commercial value is remarkably lowered, such as the gloss of the printing surface is lowered and the printing surface is roughened. Furthermore, if the solubility of the resin used is reduced in order to speed up the solvent removal, there arises a problem that the gloss of the printed surface is lowered.

As a method for solving such a problem, a method in which a predetermined amount of a polymer having a solubility parameter smaller than 19 (MPa) ^1/2 and compatible with a solvent component is contained in an offset printing ink composition (Patent Document 1). 2), and a method (Patent Document 3) in which a solvent comprising a vegetable oil component and liquid paraffin is contained in an ink composition for offset printing.

  However, the methods described in Patent Documents 1 to 3 can improve the problems of “set-off” and “blocking”, but the gloss level is not impaired, and it is rather remarkable when overprinting is performed. There is a deteriorating problem.

  Patent Document 4 discloses a printing ink composition containing a predetermined amount of an epoxy group-containing (meth) acrylic acid ester. However, this method can improve the problem of “set-off” and “blocking”, but it does not impair the original level of gloss.

  In recent years, an ultraviolet curable vehicle has been proposed as an alternative to the oxidation polymerization drying type vehicle. UV curable vehicle cures and dries in a very short time, does not require powder spraying, has excellent printing surface gloss, friction resistance, anti-set-off, blocking resistance, etc., and requires no solvent Therefore, there is no problem of fire, explosion, air pollution, etc., and it is excellent in terms of non-yellowing and low odor.

  However, there is a problem in economic efficiency because an ultraviolet irradiation facility is required. In addition, special monomers, oligomers, and photopolymerization initiators that are UV-cured are required, which increases the price. Furthermore, storage in a low-temperature environment is required, the storage period is limited, pigment dispersibility and printability, adhesion to the printing substrate is limited, effects of compounding ingredients such as pigments, and film thickness There are many problems such as different curing speeds. In addition, special solvents must be used for cleaning the printing press, and there are still many problems.

  In order to improve the respective problems of the oxidation polymerization drying type vehicle and the ultraviolet curing type vehicle, a so-called hybrid drying type using these in combination has been proposed (see, for example, Patent Documents 5 to 7). However, the hybrid drying type simply uses a blend of the conventional oxidative polymerization drying type and ultraviolet curing type, and the resulting performance is only an intermediate level of each drying method, leading to a fundamental solution. Not in. In particular, the gloss level of the paper surface is such that it does not impair the original level, and there is a problem that it is considerably lowered when overprinting is performed.

  On the other hand, in recent years, fingerprints when touching printed materials such as covers and photo albums of publications such as flat-printed posters, catalogs, calendars, flyers, wrapping papers, and weekly magazines have become particularly problematic. Adhesive. These printed materials are required to have high merchantability in combination with improvement in aesthetic sense and design, and since there are many occasions where they are touched by hand, sebum and fingerprints contained in the sweat of the hand are easily attached. As a result, the commercial value of the printed matter may be impaired, and fingerprint adhesion is a serious problem especially in highly designed printed matter such as cosmetic paper boxes, shopping bags and catalogs printed in black, and photo collections. .

  As a countermeasure to this problem, in general, in order not to impair or enhance the commercial value of these printed materials, PP (polypropylene) is applied to the printed surface, vinyl drawing, vinyl press processing or the like is performed. However, there is a problem that the cost becomes high.

  In addition, for products used or stored in high-humidity environments or environments where condensation occurs, such as liquor bottle labels, boxes containing liquor bottles, and frozen food packaging, water repellency and water resistance are required on the printed paper surface. In general, a technique of applying OP varnish to the surface of the printing paper is used to provide the above, but at present, a sufficiently satisfactory effect is not obtained.

Furthermore, in the printing market, without investing in new equipment, the existing flat printing press can be used as it is, to improve the problems of “set-off” and “blocking” during printing, improve glossiness, It is desired to reduce fingerprint adhesion and further improve water repellency and waterproofness.
JP 2002-155227 A JP 2003-147253 A JP 2002-226754 A JP 2006-8845 A Japanese Patent Laid-Open No. 11-228899 JP 2001-123100 A JP 2003-64288 A

  In light of such circumstances, the present invention is a dramatic improvement in glossiness of the printing paper surface, anti-set-off property, anti-blocking property, anti-fingerprint adhesion, in flat printing using an oxidation polymerization drying type vehicle, The objective is to make it possible to further improve water repellency and waterproofness with an existing flat printing press.

The present inventors, as a result of extensive study in detail, for the oxidative polymerization drying type vehicle, Ri Na are dispersed stabilized by specific water-soluble polymer, an acrylic copolymer having a specific glass transition temperature By adding the resin powder of the synthetic resin emulsion of the above, the gloss of the printing paper surface by the existing flat printing press is improved, the anti-set-off property, the blocking resistance, and the fingerprint adhesion resistance are dramatically improved. The present inventors have found that further improvement in waterproofness can be obtained and have completed the present invention.

That is, the present invention includes a resin powder of a synthetic resin emulsion that is dispersed and stabilized by a water-soluble polymer , the water-soluble polymer is a polyvinyl alcohol-based resin, and the resin of the synthetic resin emulsion is −5 ° C. or higher. The present invention relates to a composition for a lithographic printing liquid, which is an acrylic copolymer having a glass transition temperature . The present invention also relates to a flat printing liquid comprising the flat printing liquid composition and a vehicle.

  In the lithographic printing in the present invention, wet lithographic printing in which printing is performed while alternately applying a lithographic printing liquid and a fountain solution, the surface of the plate is coated with a silicone resin, and water is maintained by maintaining water repellency on the surface. Waterless lithographic printing which is not required, so-called dry lithographic printing is included. Also, in the printing method of the flat printing, the flat printing liquid is moved to the plate through the inking roller, then transferred from the plate to the rubber blanket, and then transferred from the rubber blanket to the printing surface for printing. A direct printing method in which a flat printing liquid is directly transferred to a printing surface is included. Since most lithographic printing is performed by an offset method, lithographic printing is often referred to as offset printing, and lithographic printing ink is often referred to as offset printing ink.

  The flat printing liquid in the present invention includes printing ink and OP varnish covering the printing surface. Basically, four colors of yellow, red, indigo and black are used as printing inks, and subtle colors can be exhibited by overprinting these inks. OP varnish is printed or coated at the end of printing for the purpose of giving the printed surface gloss or protecting the printed surface to improve friction resistance, set-off prevention, blocking resistance, etc. It is a transparent or translucent varnish that is used. The amount of printing ink or OP varnish applied to the paper surface is generally about 1 to 2 μm as the coating thickness. The “liquid” in the flat printing liquid of the present invention is a general term for substances having fluidity, and includes liquid or paste-like substances.

  According to the present invention, in flat printing using an oxidative polymerization drying type vehicle, the gloss of the printing paper surface by an existing flat printing machine is improved, anti-set-off, anti-blocking, anti-fingerprint adhesion, In addition, further improvement in water repellency and waterproofness can be obtained.

Hereinafter, although it demonstrates in detail about the structure of this invention, these show an example of a desirable embodiment.
In the following embodiments, (1) a composition for a flat printing liquid and (2) a flat printing liquid will be sequentially described.

(1) Composition for flat printing liquid The composition for flat printing liquid of this invention contains the resin powder (henceforth emulsion resin powder) of the synthetic resin emulsion by which dispersion stabilization is carried out by water-soluble polymer. It is characterized by that. First, the water-soluble polymer used in the present invention will be described.

  The water-soluble polymer in the present invention is used for the purpose of adjusting the particle size of the synthetic resin emulsion as a protective colloid (dispersion stabilizer) of the synthetic resin emulsion that is dispersed and stabilized by emulsion polymerization described later. .

  The water-soluble polymer is not particularly limited as long as it can be used as a dispersion stabilizer, and examples thereof include polyvinyl alcohol resins, hydroxyethyl cellulose, polyvinyl pyrrolidone, methyl cellulose, and water-soluble acrylic oligomers. Examples of the water-soluble acrylic oligomer include an acrylic polymer having a hydrophilic group such as a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkylene glycol group, and an amide group and having a polymerization degree of about 10 to 500. These can be used alone or in combination of two or more.

In the present invention, polyvinyl alcohol (hereinafter, PVA hereinafter) as a water-soluble polymer at least including the resin. The average saponification degree of the PVA-based resin is preferably 85 to 99.5 mol%, and more preferably 95 to 99 mol%. If the average saponification degree is too small, the polymerization may not proceed stably, and even if the polymerization is completed, the storage stability of the synthetic resin emulsion tends to be poor. Moreover, PVA-type resin with a too large saponification degree tends to be difficult to produce industrially. In the present specification, the average saponification degree can be determined in accordance with JISK 6726.

  The average degree of polymerization of the PVA-based resin is preferably 50 to 2000, more preferably 200 to 1000, and still more preferably 200 to 500. If the average degree of polymerization is too small, the protective colloid ability at the time of emulsion polymerization is insufficient and the polymerization tends not to proceed stably. If the average degree of polymerization is too large, the reaction system becomes unstable due to thickening during polymerization. Tend to be.

  In the present invention, the PVA resin means PVA itself or, for example, PVA modified with various modified species. The degree of modification by various modified species is usually 20 mol% or less, preferably 15 mol% or less, and more preferably 10 mol% or less.

  Examples of such modified species include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene; acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and the like. Unsaturated acids; or salts thereof; or mono- or dialkyl esters thereof; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, etc. Olefin sulfonic acids or salts thereof; alkyl vinyl ethers; polyoxyalkylene (meth) allyl ethers such as polyoxyethylene (meth) allyl ether and polyoxypropylene (meth) allyl ether, polyoxyethylene (meth) a Polyoxyalkylene (meth) acrylates such as relate and polyoxypropylene (meth) acrylate; polyoxyalkylene (meth) acrylamides such as polyoxyethylene (meth) acrylamide and polyoxypropylene (meth) acrylamide; polyoxyethylene [1- (Meth) acrylamide-1,1-dimethylpropyl] ester; polyoxyalkylene vinyl ethers such as polyoxyethylene vinyl ether and polyoxypropylene vinyl ether; polyoxyalkylene allylamines such as polyoxyethylene allylamine and polyoxypropylene allylamine; polyoxyethylene Polyoxyalkylene vinylamines such as vinylamine and polyoxypropylene vinylamine; N-acrylamidomethyltrimethylan Chloride, allyl trimethyl ammonium chloride, cationic group-containing unsaturated compounds such as dimethyl diallyl ammonium chloride; dimethylallyl vinyl ketone, N- vinylpyrrolidone, vinyl chloride, etc. Other unsaturated compounds of vinylidene chloride and the like.

  In the present invention, the PVA resin having an active hydrogen is a PVA resin having good reactivity with the copolymerizable monomer, excellent polymerization stability, and a high nonvolatile content synthetic resin emulsion. To preferred. When a synthetic resin emulsion having a high non-volatile content is obtained, the drying property of the synthetic resin emulsion is improved, and in particular, the heat source energy during spray drying can be saved.

  Examples of the PVA resin containing active hydrogen include acetoacetyl group-modified PVA resin, mercapto group modified PVA resin, diacetone acrylamide modified PVA resin, and the like. Among these, polymerization stability is improved. A powdered acetoacetyl group-modified PVA resin is particularly preferred from the viewpoints of improvement and stability over time of the resulting synthetic resin emulsion.

  The acetoacetylation degree of the acetoacetyl group-modified PVA resin is preferably 0.01 to 10 mol%, more preferably 0.01 to 6 mol%, and 0.03 to 3 mol%. More preferably, it is particularly preferably 0.03 to 2 mol%, and most preferably 0.03 to 1 mol%. If the degree of acetoacetylation is too small, the polymerization stability and mechanical stability tend to decrease, and the miscibility with fillers and the like tends to decrease. On the other hand, if the degree of acetoacetylation is too large, the polymerization stability during emulsion polymerization tends to be poor.

  Furthermore, the acetoacetyl groups present on the PVA molecules are preferably those that are relatively randomly arranged in the molecule rather than those that are solidly arranged in a fixed region in the molecule.

  In the acetoacetyl group-modified PVA resin, the average saponification degree is preferably 90 mol% or more, and more preferably 97 to 99.8 mol%. If the average saponification degree is too small, the polymerization does not proceed stably, and even if the polymerization is completed, the storage stability of the synthetic resin emulsion tends to be poor. On the other hand, if the degree of saponification is too large, the polymerization stability is deteriorated and gelation may occur during the polymerization, and even if the polymerization is completed, the stability over time of the emulsion tends to be deteriorated.

  Further, in the acetoacetyl group-modified PVA resin, the average degree of polymerization is preferably 50 to 2000, and more preferably 200 to 600. If the average degree of polymerization is too small, the protective colloid ability at the time of emulsion polymerization is insufficient and the polymerization tends not to proceed stably. If the average degree of polymerization is too large, the reaction system becomes unstable due to thickening during polymerization. Therefore, the re-emulsification tends to decrease.

  The production method of the acetoacetyl group-modified PVA resin is not particularly limited, and can be produced by a known method, for example, a method in which diketene is reacted with the PVA resin. Specifically, a method of dispersing a PVA resin in an acetic acid solvent and adding diketene thereto, a method of previously dissolving a PVA resin in a solvent such as dimethylformamide or dioxane, and adding diketene thereto, PVA system Examples thereof include a method in which gaseous or liquid diketene is brought into direct contact with the resin.

  In the present invention, whether the PVA resin has active hydrogen or does not have active hydrogen, the side chain of the PVA resin is added to the side chain of the PVA resin from the viewpoint of increase in non-volatile content of emulsion, ease of polymerization, etc. More preferred is a PVA-based resin having a 1,2-diol bond. As the PVA resin having a 1,2-diol bond in the side chain, a PVA resin containing a 1,2-diol structural unit represented by the following general formula (1) is usually mentioned.

[In the general formula (1), R ¹ , R ² , and R ³ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. ]

  In the PVA resin having a 1,2-diol bond in the side chain, the average degree of saponification is preferably 85 to 100 mol%, more preferably 90 to 99.8 mol%. If the average degree of saponification is too small, the stability of the emulsion during polymerization tends to decrease, and it becomes difficult to obtain the intended emulsion.

  Moreover, in the PVA resin having a 1,2-diol bond in the side chain, the average degree of polymerization is preferably 50 to 2500, more preferably 100 to 1700, still more preferably 100 to 1000, and particularly preferably 200 to 500. is there. If the average degree of polymerization is too small, it tends to be difficult to industrially produce a PVA-based resin. If the average degree of polymerization is too large, the viscosity of the emulsion becomes too high or the polymerization stability of the emulsion is low. There is a tendency to decrease.

  The amount of 1,2-diol bonds in the side chain in the PVA-based resin is preferably 1 to 15 mol%, more preferably 1 to 12 mol%, still more preferably 2 to 10 mol%, still more preferably. 2 to 8 mol%. If the content of the 1,2-diol component is too small, the mechanical stability of the emulsion and the water resistance of the film tend to be lowered. If the content is too large, the stability during polymerization is lowered and non-volatile. It tends to be difficult to obtain a stable emulsion having a minute content.

  PVA resins having a 1,2-diol bond in the side chain are, for example, (a) a method of saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene, Saponification and decarboxylation of a copolymer with vinyl ethylene carbonate, (c) Saponification and deketalization of a copolymer of vinyl acetate and 2,2-dialkyl-4-vinyl-1,3-dioxolane And (d) a method of saponifying a copolymer of vinyl acetate and glyceryl monoallyl ether.

  The amount of water-soluble polymer used to disperse and stabilize the synthetic resin emulsion allows the emulsion polymerization to proceed smoothly, allows easy control of the polymerization, and prevents the generation of coarse particles and block-like substances generated during the polymerization. For example, it is preferably 3 to 20% by weight, more preferably 4 to 10% by weight in terms of solid content, based on the total monomer. Although depending on the final non-volatile content of the emulsion, if the amount of the water-soluble polymer used is too large, the viscosity of the emulsion itself increases during the polymerization, and the possibility that the stable state cannot be maintained tends to increase. On the other hand, if the amount used is too small, coarse particles and block-like substances are likely to be generated during the polymerization, and it is difficult to maintain a stable state.

  In the present invention, as the PVA resin, the PVA resin can be used alone or in admixture of two or more. For example, PVA resin having active hydrogen and 1,2-diol in the side chain A PVA resin having a bond can be used in combination.

  In the present invention, the water-soluble polymer, particularly the PVA resin, is usually used as an aqueous solution using an aqueous medium in the course of emulsion polymerization. Here, the aqueous medium refers to water or an alcoholic solvent mainly composed of water, preferably water. The amount of the water-soluble polymer in this aqueous solution (in terms of nonvolatile content) is not particularly limited, but is preferably 5 to 30% by weight from the viewpoint of easy handling.

Next, a synthetic resin of a synthetic resin emulsion that is dispersed and stabilized by a water-soluble polymer will be described.
Synthetic resin used in the present invention has a glass transition temperature of -5 ° C. or higher, more preferably 30 ° C. or higher, even more preferably 45 ° C. or higher. The upper limit of the glass transition temperature is usually 110 ° C., preferably 90 ° C., more preferably 70 ° C. If the glass transition temperature is too low, the effects of fingerprint resistance, anti-set-off, blocking resistance, and water repellency and waterproof properties tend to be reduced. In addition, in order to prevent blocking due to the caking / aggregation of particles that are likely to occur during storage of the resin powder, about 15 to 30% by weight of fine powder calcium carbonate or the like is added and kept in a state of being dusted. Such a treatment is necessary, and the added fine powder tends to roughen the printing paper surface. These glass transition temperatures (Tg values) can be calculated from the FOX equation.

The synthetic resin in the present invention, typically, an acrylic copolymer. The acrylic copolymer is a copolymer containing an acrylic monomer or an aromatic vinyl monomer as a main copolymer component.

  Examples of the acrylic monomer constituting the acrylic copolymer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, stearyl (meth) acrylate, lauryl ( In addition to aliphatic (meth) acrylates such as meth) acrylate, alicyclic (meth) acrylates such as cyclohexyl (meth) acrylate, aromatic (meth) acrylates such as benzyl (meth) acrylate, dimethylaminoethyl ( ) Acrylate, diethylaminoethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, etc., among which methyl (meth) acrylate, ethyl (meth) An aliphatic (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, such as acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate is preferably used. One of these monomers may be used, or two or more may be used in combination. Here, “(meth) acrylate” means acrylate or methacrylate.

  The content of the acrylic monomer is preferably 30% by weight or more, particularly preferably 50% by weight or more, and the upper limit is preferably 90% by weight or less, particularly preferably 80% by weight or less, based on the entire copolymerization component. It is.

  The acrylic copolymer preferably contains an aromatic vinyl monomer as a copolymerization component. The content of the aromatic vinyl monomer is preferably 10% by weight or more, particularly preferably 20% by weight or more with respect to the copolymer component. Further, the upper limit of the content of the aromatic vinyl monomer is usually 70% by weight, preferably 50% by weight. Examples of the aromatic vinyl monomer include styrene and α-methylstyrene, and styrene is more preferable because of easy polymerization. If the copolymerization amount of the aromatic vinyl monomer is too small, it tends to be difficult to contribute to improvement of glossiness in the flat printing liquid.

  If necessary, the acrylic copolymer may be introduced with a carboxyl group-containing monomer and neutralized with alkali to enhance the stability of the synthetic resin emulsion particles themselves. The resin powder of a synthetic resin emulsion that has been neutralized with a carboxyl group-containing monomer has the following characteristics: kneading / mixing stability with vehicle, transferability, mechanical stability on the plate, and dispersibility of pigments, etc. It is also preferable in terms of improvement. As the carboxyl group-containing monomer, ethylenic mono- and dicarboxylic acids are preferable, and examples thereof include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, crotonic acid, and itaconic acid. These can be used alone or in combination of two or more. Among these, acrylic acid, methacrylic acid, and maleic anhydride are more preferable. The amount of the carboxyl group-containing monomer used is preferably 0.05 to 5% by weight, more preferably 0.1 to 3% by weight, based on the total monomers. If the amount used is too small, the above effects tend not to be expected. If the amount used is too large, the viscosity tends to be affected when added to the vehicle. In addition, the same effects as described above can be imparted by including an acid-modified alkyd resin, an acid-modified acrylic resin, and an acrylic / styrene resin. In this case, you may mix | blend at the time of superposition | polymerization of an acryl-type copolymer, or may add after superposition | polymerization.

  Moreover, in the range which does not inhibit the objective of this invention, the copolymerizable monomer other than the above can be used together. For example, vinyl monomers such as vinyl acetate, vinyl propionate, vinyl carboxylate such as vinyl versatate, nitrile monomers such as (meth) acrylonitrile, amide monomers such as (meth) acrylamide, vinyl monomers such as alkyl vinyl ether such as methyl vinyl ether, Examples thereof include olefin monomers such as ethylene and diene monomers such as butadiene. These can be used alone or in combination of two or more. In some cases, it is also possible to use a resin powder made of a copolymer of the above vinyl carboxylate and an olefin monomer.

  Furthermore, within a range not inhibiting the purpose of the present invention, a glycidyl group-containing monomer, a hydrolyzable silyl group-containing monomer, an acetoacetyl group-containing monomer, a hydroxyl group-containing monomer, a monomer having two or more vinyl groups in the molecular structure, allyl Functional group-containing monomers such as group-containing monomers, sulfonic acid group-containing monomers, amide group-containing monomers, and carbonyl group-containing monomers can be used in combination.

  Specific examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate, glycidyl (meth) allyl ether, 3,4-epoxycyclohexyl (meth) acrylate, and the like.

  Specific examples of the hydrolyzable silyl group-containing monomer include, for example, vinyltrialkoxysilanes such as vinyltrimethoxysilane and vinyltriethoxysilane; vinylalkyldialkoxysilanes such as vinylmethyldimethoxysilane and vinylmethyldiethoxysilane; γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltrialkoxysilane such as γ- (meth) acryloxypropyltriethoxysilane; γ- (meth) acryloxypropylmethyldimethoxysilane, γ Γ- (meth) acryloxypropylalkyldialkoxysilane such as-(meth) acryloxypropylmethyldiethoxysilane; vinyltris (β-methoxyethoxy) silane and the like.

  Specific examples of the acetoacetyl group-containing monomer include, for example, acetoacetoxyalkyl (such as vinyl acetoacetate, allyl acetoacetate, allyl acetoacetate, acetoacetoxyethyl (meth) acrylate, acetoacetoxypropyl (meth) acrylate) Meth) acrylates; acetoacetoxyalkyl crotonates such as acetoacetoxyethyl crotonate and acetoacetoxypropyl crotonate; 2-cyanoacetoacetoxyethyl (meth) acrylate and the like.

  Specific examples of the hydroxyl group-containing monomer include, for example, an alkyl group such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like having 1 to 10 carbon atoms, particularly 1-6 hydroxyalkyl (meth) acrylate etc. are mentioned.

  Specific examples of the monomer having two or more vinyl groups in the molecular structure include, for example, divinylbenzene; diallyl phthalate; triallyl cyanurate; triallyl isocyanurate; ethylene glycol di (meth) acrylate, 1,2-propylene Glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) Examples include alkylene glycol (meth) acrylate such as acrylate; trimethylolpropane tri (meth) acrylate; allyl (meth) acrylate and the like.

  Specific examples of the allyl group-containing monomers include, for example, monomers having two or more allyl groups such as triallyloxyethylene, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane; allyl glycidyl ether ; And allyl acetate.

Specific examples of the sulfonic acid group-containing monomer include 2-acrylamido-2-methylpropanesulfonic acid.
Specific examples of the amide group-containing monomer include (meth) acrylamide, N, N-dimethylacrylamide, t-butylacrylamide, diacetone acrylamide and the like.
Specific examples of the carbonyl group-containing monomer include, for example, diacetone acrylamide.
Among these functional group-containing monomers, one type can be used alone, or two or more types can be used in combination.

  Use of these functional group-containing monomers is effective in modifying a copolymer that becomes brittle as the glass transition temperature of the polymer increases to a stronger copolymer. It is also effective for mechanical stability during mixing and mixing. Furthermore, there is an effect that contributes to adhesion to the printing base. The amount used is preferably 0.05 to 10% by weight, more preferably 0.1 to 5% by weight, still more preferably 0.5 to 2% by weight, based on the total monomers. If the amount used is too small, a tough copolymer tends to be difficult to obtain. If the amount used is too large, the stability during copolymerization and the stability over time of the resulting synthetic resin emulsion tend to deteriorate. is there.

  Next, the production of the synthetic resin emulsion and the production of the resin powder from this emulsion will be described.

  The synthetic resin emulsion used in the present invention is a dispersion stabilized by a water-soluble polymer, but in some cases, for example, it is necessary to prevent the generation of coarse particles and block-like substances generated during polymerization. In some cases, a surfactant is used together with a water-soluble polymer, and various monomers, for example, an acrylic or acrylic / styrene monomer as a main component, and if necessary, a copolymer component containing a functional group-containing monomer is emulsion-polymerized. Can be manufactured.

  The surfactant is not particularly limited as long as it can emulsify and disperse the synthetic resin emulsion. For example, anionic surfactants such as sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate, sodium alkyldiphenyl ether disulfonate, etc. A nonionic surfactant having a polyoxyethylene alkyl ether type structure or a pluronic type structure, and a so-called reactive surfactant having a radical polymerizable unsaturated bond in the structure can be used. If necessary, a cationic surfactant can also be used. Actually, a combination of an anionic surfactant and a nonionic surfactant is desirable.

  As the surfactant, in addition to the surfactant for emulsion polymerization described above, an oil-soluble emulsifier having a low HLB and an emulsifier for mineral oil can be further used. By post-adding an emulsifier having a low HLB to the synthetic resin emulsion, the synthetic resin emulsion can be made into a resin powder and easily added to the vehicle when added to the vehicle.

  As a method of emulsion polymerization, for example, water, a water-soluble polymer, and a surfactant as necessary are charged into a reaction can, and after raising the temperature to obtain an aqueous solution, the monomer and the polymerization catalyst are added dropwise. Examples thereof include a drop type emulsion polymerization method and an emulsion monomer drop type emulsion polymerization method in which a monomer to be dropped is preliminarily emulsified and dispersed with a water-soluble polymer and water, and then dropped into an aqueous solution in a reaction vessel to be polymerized. From the aspects of management of the polymerization process and controllability of the polymerization itself, the monomer dropping type emulsion polymerization method is convenient.

  More specifically, the emulsion polymerization process by the monomer dropping method will be described as follows. First, 90 to 95% by weight of the total amount of water, a total amount of water-soluble polymer, and a buffer and a surfactant as necessary are charged in a reaction can and heated to 70 to 80 ° C. A part of an aqueous solution of the catalyst and the polymerization catalyst (using 5 to 10% by weight of the total water amount) is added in advance, and initial polymerization is carried out. Next, the polymerization is allowed to proceed while dropping the remaining aqueous solution of the remaining monomer mixture and the remaining polymerization catalyst into the reaction vessel. When it is determined that the polymerization is complete, the reaction vessel is cooled, and the target emulsion is taken out.

  As the emulsion polymerization catalyst, inorganic or organic peroxides can be used. For example, peroxo acid compounds such as potassium persulfate, sodium persulfate and ammonium persulfate; hydrogen peroxide; di-t-butyl peroxide, benzoyl peroxide, t-butyl perbenzoate, t-butyl peroctoate, t-butyl Peroxide compounds such as hydroperoxide and cumene hydroperoxide; azobisisobutyronitrile, dimethylazodiisobutyrate, 2,2-azobis (2,4-dimethylvaleronitrile), 2,2-azobis (2-methyl) Azo compounds such as butyronitrile) and redox polymerization initiators combining these with reducing agents such as sodium acid sulfite and L-ascorbic acid. These polymerization catalysts may be used alone or in combination of two or more. Among these, ammonium persulfate and potassium persulfate are preferable in terms of easy emulsion polymerization. The amount of the polymerization catalyst used is usually 0.1 to 2% by weight based on the total monomers.

  Usually, in emulsion polymerization, a copolymerizable monomer, a water-soluble polymer and a polymerization catalyst can be used, and other components can be further used as necessary. Examples of such other components include the above-mentioned surfactants, polymerization regulators, auxiliary emulsification / dispersion stabilizers, plasticizers, and the like. The reaction conditions for emulsion polymerization can be appropriately selected according to the type of copolymerizable monomer, the use and purpose of the flat printing liquid, and the like.

  As a polymerization regulator, it can select suitably from well-known things. Examples of such a polymerization regulator include a chain transfer agent and a buffer.

  Examples of chain transfer agents include lower alcohols such as methanol, ethanol, and propanol; aldehydes such as acetaldehyde, propionaldehyde, and n-butyraldehyde; and dodecyl mercaptan, lauryl mercaptan, thioglycolic acid, octyl thioglycolate, and the like. Of mercaptans. Among these chain transfer agents, one type may be used alone, or two or more types may be used in combination. By using a chain transfer agent, the polymerization can be performed stably, but the degree of polymerization will be reduced and the toughness and elasticity of the film will be impaired. Is desirable.

  Examples of the buffer include sodium acetate, ammonium acetate, dibasic sodium phosphate, and the like. Among these buffers, one type may be used alone, or two or more types may be used in combination.

  Examples of the auxiliary emulsification / dispersion stabilizer include so-called pluronic emulsifiers and naphthalene sulfonic acid polymer activators for polyoxyethylene / polyoxypropylene block polymers.

  As the plasticizer, adipate plasticizers, phthalic acid plasticizers, phosphoric acid plasticizers and the like that are generally used for paints and adhesives can be used.

  The amount of these other components used is not particularly limited as long as the object of the present invention is not impaired, and can be appropriately set according to the object.

  The synthetic resin emulsion thus obtained preferably has a weight average molecular weight of 100,000 to 2,000,000, more preferably 200,000 to 1,000,000. If the weight average molecular weight is too small, the object of the present invention tends to be difficult to achieve. If the weight average molecular weight is too large, gelation tends to occur during the polymerization, particularly when the nonvolatile content of the synthetic resin emulsion is high. is there.

  The average particle size of the synthetic resin in the synthetic resin emulsion is preferably 0.05 to 1 μm, more preferably 0.07 to 0.3 μm. If the average particle size is too small, the apparent weight average particle size of the obtained resin powder becomes small, so that dust easily rises during handling, and the working environment is deteriorated, and a flat printing liquid containing this resin powder is used as a base material. When printed on the substrate, the particle diameter of the resin powder present in the printed layer formed on the substrate tends to be too small with respect to the thickness of the printed layer, making it difficult to achieve the object of the present invention. On the other hand, if the average particle size is too large, the weight average particle size of the obtained resin powder becomes too large, so that it becomes difficult to mix this resin powder uniformly in the flat printing liquid, and the resin powder present in the printing layer is removed. It tends to be difficult to adjust to a desired particle size. That is, when the printing paper surface is rough or rubbed, it tends to be easily damaged.

  Further, the non-volatile content of the synthetic resin emulsion is preferably adjusted to 30 to 60% by weight, particularly 40 to 50% by weight. If the non-volatile content is too small, a large amount of heat for drying is required in spray drying, resulting in an economical problem such as an increase in production cost, and drying tends to be insufficient. On the other hand, if there is too much non-volatile content, the viscosity of the synthetic resin emulsion becomes too high, spraying itself does not become smooth, and it tends to be difficult to obtain a resin powder having the desired particle size.

  When manufacturing resin powder from a synthetic resin emulsion, a drying process is performed. Examples of the drying method for producing the resin powder of the synthetic resin emulsion include spray drying, freeze drying, and hot air drying after coagulation. Among these, spray drying is preferable from the viewpoint of production cost and energy saving.

  Examples of the spray format in spray drying include a disk type and a nozzle type. Examples of the heat source for spray drying include hot air and heated steam. The conditions for spray drying can be appropriately set according to the size and type of the spray dryer, the nonvolatile content of the synthetic resin emulsion, the viscosity, the flow rate, and the like. The temperature of spray drying is usually about 80 to 150 ° C.

  The spray drying process will be described more specifically. First, the non-volatile content in the synthetic resin emulsion is adjusted, and this is continuously supplied from the nozzle of a spray dryer, and the mist is dried by hot air to be powdered. In some cases, the spray solution of the synthetic resin emulsion with adjusted non-volatile content is preheated during spraying and continuously supplied from the nozzle, and the atomized product can be dried with warm air to be powdered. . Preheating before spraying not only increases the drying speed but also increases the non-volatile content in the spray liquid as the viscosity of the spray liquid decreases, contributing to a reduction in production costs.

  The resin powder obtained by spray drying takes a form in which several tens to several hundreds of polymer particles (particle size is about 0.05 to 1 μm) in the synthetic resin emulsion before spraying are entangled. The apparent weight average particle diameter of the emulsion resin powder is preferably about 5 to 200 μm, more preferably 20 to 100 μm, based on the ease of work when the emulsion resin powder is blended into the vehicle. When the apparent weight average particle diameter is too small, dust rises during handling and the working environment tends to deteriorate. If the apparent weight average particle size is too large, it tends to take a long time to add to the vehicle and perform kneading and dispersion with a bead mill or a three-roll mill. That is, it tends to be difficult to sufficiently knead and disperse the OP varnish and ink within a general kneading and dispersing time.

  The apparent weight average particle diameter of the emulsion resin powder can be usually measured using a sonic vibration type automatic sieve divided particle size distribution measuring device in which sieves are stacked in multiple stages. For example, by using a robot shifter RPS-85 manufactured by Seishin Co., Ltd., by setting an appropriate eight-stage sieve with 20 to 300 μm “bitter light” based on JIS-Z8801, and classifying emulsion resin powder products, The apparent weight average particle diameter (unit: μm) can be determined.

  In producing the emulsion resin powder, various additives can be added before or after the drying treatment, if necessary. Examples of such additives include dispersants for dispersing organic / inorganic pigments, pigments / fillers, thickeners, ultraviolet absorbers, antioxidants, and the like. When these additives are powder products, they may be added directly to the emulsion resin powder after the drying treatment. The antioxidant is preferably added to the synthetic resin emulsion before the drying treatment.

  The ultraviolet absorber is added in order to prevent the printed paper surface from being yellowed by sunlight or the like to reduce the commercial value. As the ultraviolet absorber, those generally used for paints can be used. For example, a benzophenone-based or benzotriazole-based UV absorber, a hindered amine light stabilizer, or the like can also be used, and these can be used alone or in combination of two or more.

  Antioxidants are effective in preventing electrostatic explosions when handling emulsion resin powders. As the antioxidant, those generally used for general purposes can be used. For example, a phenol type, bisphenol type, phosphorus type antioxidant, etc. are mentioned. These can be used alone or in combination of two or more, and are preferably added to the synthetic resin emulsion before pulverization.

  In the present invention, the anti-caking agent is mixed with the synthetic resin emulsion before spray drying, mixed with the emulsion resin powder after spray drying, or sprayed with the synthetic resin emulsion as needed. It can be used in combination, for example, by spraying from another nozzle.

  By using an anti-caking agent in combination, it becomes a state where an emulsion resin powder is applied with an anti-caking agent, and it is possible to prevent particles from caking and agglomerating and blocking during storage etc. Become.

  It does not restrict | limit especially as an anti-caking agent, For example, a well-known inactive inorganic fine powder or organic fine powder can be used. Examples of the inorganic fine powder include calcium carbonate, talc, and clay. As the organic fine powder, for example, a resin powder obtained by spray drying a synthetic resin emulsion containing a synthetic resin having a glass transition temperature of 70 ° C. or higher can be used. The amount of the anti-caking agent used is preferably 1 to 15% by weight, particularly preferably 5 to 12% by weight, based on the resulting emulsion resin powder. When the amount of the anti-caking agent is increased, not only the gloss is lowered, but also the surface of the printing paper is roughened and the commercial value tends to be lowered. These anti-caking agents can be used alone or in combination of two or more. For example, organic fine powder and inorganic fine powder can be used in combination.

(2) Flat printing liquid The flat printing liquid of the present invention is characterized by containing the above-mentioned composition for a flat printing liquid and a vehicle, and the above-described composition for a flat printing liquid and a vehicle are mixed. Not only the prepared lithographic printing liquid but also those obtained by blending at least the above emulsion resin powder with a commonly used lithographic printing liquid are included.

  The content of the emulsion resin powder in the flat printing liquid is preferably from 0.3 to 10% by weight, more preferably from 1 to 5% by weight, based on the total composition (whole liquid). If the content is too small, it tends to be difficult to improve glossiness of the printing paper surface, fingerprint adhesion, anti-set-off, blocking resistance, and water repellency and water resistance. The viscosity increases, the fluidity and transferability deteriorate, and the so-called piling phenomenon tends to occur. Also, the anti-fingerprint property, the anti-set-off property, the water repellency and the waterproof property tend to be improved, but the glossiness tends not to be improved so much.

  The vehicle generally contains a binder, vegetable oil (optionally processing oil) and a high-boiling solvent, and optionally contains a plasticizer.

  The binder used in the vehicle is not particularly limited. For example, rosin-modified phenolic resins, rosin-modified maleic resins, styrene / maleic resins, alkyd resins (including fatty acid-modified semi-drying oil type polyester resins) ) And petroleum resins. Resins or the like in which a copolymerizable unsaturated double bond is introduced into an acrylic copolymer skeleton can also be used. In particular, it is desirable to use rosin-modified phenolic resins and alkyd resins because of a good balance of performance as a resin. These resins can be used individually by 1 type, or can also use 2 or more types together suitably. The binder content in the flat printing liquid is usually 25 to 60% by weight, preferably 35 to 55% by weight. If the content of the binder is too small, the adhesion / adhesion effect as a binder tends to be difficult to obtain, and the dispersibility of pigments and the like tends to decrease. When the content of the binder is too large, drying tends to be delayed, and physical properties such as wear resistance, anti-set-off property, and blocking resistance tend to be deteriorated.

  As the vegetable oil used in the vehicle, those of the dry oil / semi-dry oil type can be used without particular limitation. For example, in addition to linseed oil, tung oil, soybean oil, safflower oil, etc., these vegetable oils are processed by various methods to improve dryness, gloss, water resistance, etc., or to increase the viscosity. It can also be used as a processing oil. For example, linseed oil is heated and polymerized at 180 to 250 ° C. for 1 to 2 hours to increase viscosity, non-drying castor oil is heated and dehydrated in the presence of a catalyst to form dehydrated castor oil, Monoesterified products such as methyl, ethyl, butyl, and propyl such as soybean oil are also used. These vegetable oils can be used alone or in combination of two or more. The vegetable oil content in the lithographic printing liquid is usually 20 to 60% by weight, preferably 35 to 55% by weight. When there is too little content of vegetable oil, there exists a tendency for abrasion resistance, dryness, and gloss to be not enough. When there is too much content of vegetable oil, there exists a tendency for set property and blocking resistance not to be enough.

  The solvent used in the vehicle is preferably a solvent that has appropriate solubility or dilutability and a desired evaporation rate for the resin to be used, and that gives the viscosity and fluidity required for the flat printing liquid. Can be used. And those which are suitable for the environment, have little odor and toxicity, and do not adversely affect the printed matter can be particularly suitably used. For example, an aliphatic hydrocarbon solvent, which is a petroleum solvent having a boiling point of 230 to 320 ° C., is distilled and a fraction is cut at a width of about 20 ° C. Specifically, Nippon Oil Corporation's No. 0, No. 4 to No. 7 solvent, which is a typical aliphatic hydrocarbon solvent, is desirable, and in recent years from the viewpoint of environmental measures, the content of aromatic hydrocarbons Is more preferably 1% by weight or less and the use of AF4 to 7 solvent of Nippon Oil Corporation having a boiling point of 200 ° C. or higher. These solvents can be used alone or in combination of two or more.

  Furthermore, various solvents such as n-paraffinic, isoparaffinic, naphthenic, α-olefins, higher alcohols, glycols and derivatives thereof, liquid paraffin, mineral spirits, mineral oils, and the like do not impair the purpose of the present invention. Can be used. The content of the solvent in the flat printing liquid is appropriately set according to the type and use of the flat printing liquid.

  The flat printing OP varnish and the flat printing ink (hereinafter collectively referred to as “OP varnish / ink”) as flat printing liquids are not only printable but also dry, productive, glossy, Generally, various additives are contained because performance and physical properties such as wear resistance, set-off prevention, and blocking resistance are required. For example, metal dryers that promote the oxidative polymerization and drying of drying oils and semi-drying oils as vegetable oils, anti-set-off agents that prevent set-off and blocking that occur when printed materials are placed on top of each other, and slipping on the film Examples of the main additive include waxes that impart wear resistance and improve wear resistance.

  Drying on the paper surface on which OP varnish / ink is printed is usually oxidative polymerization drying. Specifically, OP varnish / ink containing drying oil or processing oil with unsaturated double bond in the molecule such as linseed oil is printed and transferred as a thin layer on the surface of paper etc. As a result, the surface area of the OP varnish / ink is expanded, absorbs oxygen in the air, oxidatively polymerizes and solidifies, forms a film, and dries.

  A metal dryer promotes this oxidative polymerization drying, and a vehicle marketed for OP varnish / ink contains an appropriate amount of metal dryer. The metal dryer is generally a metal salt of an organic acid such as octylic acid, stearic acid or naphthenic acid and a transition metal such as cobalt or manganese. The content of the metal dryer in the OP varnish / ink is preferably 0.3 to 3% by weight.

  Further, if necessary, in addition to a metal dryer that promotes oxidative polymerization drying, an amount of a reactive curing agent that does not impair the storage stability of the OP varnish / ink itself can be used in combination. Examples of the reactive curing agent include metal alkoxides and metal chelates.

  As drying on the paper surface of OP varnish / ink, etc., the above-mentioned oxidation polymerization drying is generally used. However, for example, thermal polymerization drying and ultraviolet curing (photopolymerization drying) can also be performed in combination. is there. In particular, thermal polymerization drying has a meaning of complementing oxidation polymerization drying. UV curing (photopolymerization drying) involves printing OP varnish / ink blended with acrylic oligomers / acrylic monomers and a photopolymerization initiator, then irradiating ultraviolet rays to generate radicals, and instantly chain radicals. This is a system in which polymerization is advanced to solidify and dry. However, UV curing has problems such as low pigment dispersibility, printability, and adhesion to the substrate, as well as odor generation due to residual monomers and high price compared to oxidation polymerization drying. Combination of curing is not desirable.

  In order to print OP varnish / ink under optimum printing conditions, it is necessary to consider the temperature and humidity of the printing chamber, the type of substrate, the printing speed, the plate pattern, and the like. In addition, when stacking printed materials quickly, there is a problem of “back-off” where the back side of the printed material is stained with printing ink, and when drying is slower, there is a problem such as “blocking” that gets stuck on the back / front of the printed material. Considering these, it is desirable to take measures to add additives to the OP varnish / ink in advance.

  Examples of the anti-set-off agent for preventing “set-off” and “blocking” include silicone-treated processed starch and magnesium carbonate. The addition amount of the anti-set-off agent is desirably 5% by weight or less, particularly 3% by weight or less based on the OP varnish / ink. When the addition amount is increased, there is a tendency that plate residue, plate clogging, blanket residue and the like are likely to occur. However, in general, the effect of preventing set-off by the addition of the set-off preventing agent is not so great, and in reality, so-called powder spraying is performed in which fine powder such as starch is sprayed on the printing surface immediately after printing. . However, this method causes fine powder to easily scatter and float around the printing press, which is problematic for environmental hygiene and adheres to the printing surface, resulting in a decrease in gloss and a rough surface. It may adversely affect processing. According to the lithographic printing liquid of the present invention (for example, OP varnish / ink), the effect of preventing the set-off is improved, and a sufficient effect can be obtained only by blending the set-up preventing agent without spraying the powder.

  Examples of waxes that improve the abrasion resistance by imparting lubricity to the film include polyethylene wax, carnauba wax, polytetrafluoroethylene, and paraffin wax. By blending these, a thin film is formed on the printing surface. In particular, it is possible to improve the wear resistance by imparting lubricity to the film. Furthermore, there are effects such as reduction of ink tack, prevention of set-off, prevention of blocking, and imparting water repellency.

  When the lithographic printing liquid of the present invention is an ink for lithographic printing, various inorganic / organic pigments and optionally dyes may be blended as a colorant without any particular limitation. For example, inorganic pigments such as titanium dioxide, petal, carbon black, iron oxide, extender pigments such as calcium carbonate and barium sulfate, organic pigments such as azo pigments, lake pigments, phthalocyanine pigments, isoindoline pigments, anthraquinone pigments and quinacridone pigments Etc. are used as colorants. The content of the colorant in the lithographic printing ink is preferably 3 to 40% by weight.

  The flat printing liquid of the present invention may further contain other additives. Other additives are not particularly limited as long as they do not impair the object of the present invention. For example, organic and inorganic dispersants and wetting agents, surfactants, thickeners, gelling agents, thixotropic agents, Matting agents, anti-skinning agents / drying inhibitors, UV absorbers / light stabilizers, plasticizers, and the like are used as necessary. More specifically, for example, an oil emulsifier or mineral oil emulsifier having a low HLB value can be blended in the flat printing liquid for the purpose of increasing dispersibility of a colorant or the like. These emulsifiers may be added before subjecting the synthetic resin emulsion to a drying treatment.

  When the flat printing liquid of the present invention is printed on a substrate such as paper, the particle diameter of the emulsion resin powder present in the printing layer such as an OP varnish layer and an ink layer formed on the substrate is It has a particle diameter of 2 to 20 times, particularly 3 to 15 times, and further 5 to 12 times the thickness, which improves the glossiness of the printing paper surface, resistance to fingerprint adhesion, anti-settling and blocking resistance From the viewpoint of the object of the present invention, that is, improvement of water repellency and water repellency and waterproofness. If the particle diameter of the emulsion resin powder is too small with respect to the thickness of the printed layer, it tends to be difficult to achieve the object of the present invention. Conversely, if the particle diameter is too large, the object of the present invention can be achieved. Although it is possible, the printed paper surface becomes rough and, when rubbed, it tends to be easily scratched.

In order to obtain the particle size of the emulsion resin powder present in the printing layer such as the OP varnish layer or the ink layer, measurement with an electron microscope is more preferable. However, as a simple method, a flat printing liquid (for example, OP varnish / ink) It can be measured by using a grind meter for examining the meat paste and dispersibility of.
The emulsion resin powder present in the printing layer is mixed with a vehicle, and then kneaded and dispersed in a bead mill, a three-roll mill, etc., so that the particle diameter is reduced by ripening.

  As a method for producing the flat printing liquid of the present invention, for example, a known method can be employed. For example, binders such as rosin-modified phenolic resins, drying oils / semi-drying oils and / or vegetable oils such as processing oils obtained by heat polymerization of these, high boiling point solvents (which may further contain a plasticizer), etc. 180 to 250 ° C. For 1 to 2 hours to prepare a vehicle. Alternatively, the vehicle is prepared by mixing the binder, vegetable oil, high boiling point solvent (which may further contain a plasticizer) and the like at room temperature. Next, in the case of a high boiling point solvent (preferably a solvent similar to that used in the preparation of the vehicle), a metal dryer, an anti-set-off agent (more vegetable oil if necessary), and ink for lithographic printing, further coloring such as pigments Add the agent / pigment dispersant, if necessary, other additives to the above-mentioned vehicle, add the composition for the lithographic printing liquid of the present invention, knead and disperse with a bead mill or triple roll mill, etc. The OP varnish / ink can be manufactured by adjusting the properties.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded. In the examples, “parts” and “%” mean weight basis unless otherwise specified.

Production example of synthetic resin emulsion
Emulsion 1
In a 1 L glass reaction can equipped with a condenser, thermometer and stirrer, 500 parts of water, 1 part of sodium acetate trihydrate and a degree of saponification of about 99 moles having 1,2-diol bonds in the side chain %, Average degree of polymerization of about 300, and 32 parts of modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having a side chain 1,2-diol bond content of 8 mol%, and heated to 85 ° C., This PVA was dissolved. Next, keeping the temperature of the reaction vessel at about 80 ° C., 43 parts of a prepared monomer (320 parts of methyl methacrylate, 107 parts of butyl acrylate, 427 parts of monomers in total) and a polymerization catalyst 4 parts of 8% aqueous ammonium persulfate solution was added and initial polymerization was carried out for 45 minutes. Subsequently, the remaining mixed monomer and 10 parts of an 8% aqueous ammonium persulfate solution as a polymerization catalyst were continuously dropped over 3 hours to proceed the polymerization. After aging at the same temperature for 1 hour, it was cooled to room temperature. Emulsion 1 having a nonvolatile content of 47.1% was obtained.
The calculated glass transition temperature (Tg) of the copolymer composed of this main monomer composition (methyl methacrylate / butyl acrylate = 320 parts / 107 parts = 75/25 (wt%)) is obtained by adding the Tg of each homopolymer to +105 When it is set to ° C and -52 ° C, it is about + 48 ° C.

Emulsion 2
Emulsion 2 having a nonvolatile content of 47.0% was obtained in the same manner as emulsion 1, except that the composition ratio of the main monomer was changed to methyl methacrylate / butyl acrylate = 384 parts / 43 parts.
The calculated glass transition temperature (Tg) of the copolymer composed of this main monomer composition (methyl methacrylate / butyl acrylate = 384 parts / 43 parts = 90/10 (% by weight)) is obtained by adding the Tg of each homopolymer to +105. When it is set to ° C and -52 ° C, it is about + 80 ° C.

Emulsion 3
Emulsion 1 except that the composition ratio of the main monomer was changed to methyl methacrylate / styrene / butyl acrylate = 150 parts / 149 parts / 128 parts, and 5 parts of glycidyl methacrylate was added instead of acrylic acid as a functional group-containing monomer. In the same manner as above, an emulsion 3 having a nonvolatile content of 47.3% was obtained.
The calculated glass transition temperature (Tg) of the copolymer consisting of this main monomer composition (methyl methacrylate / styrene / butyl acrylate = 150 parts / 149 parts / 128 parts / = 35/35/30 (wt%)) is: When the Tg of each homopolymer is + 105 ° C, + 100 ° C, and -52 ° C, it is about + 37 ° C.

Emulsion 4
Instead of PVA having a 1,2-diol bond in the side chain, an acetoacetyl group-modified PVA having a saponification degree of about 98 mol%, an average degree of polymerization of about 300, and an acetoacetylation degree of 0.5 mol% (Japan) Emulsion 4 having a non-volatile content of 47.2% was obtained in the same manner as Emulsion 1 except that it was changed to Synthetic Chemical Industry Co., Ltd.
The calculated glass transition temperature (Tg) of the copolymer composed of this main monomer composition (methyl methacrylate / butyl acrylate = 320 parts / 107 parts = 75/25 (wt%)) is obtained by adding the Tg of each homopolymer to +105 When it is set to ° C and -52 ° C, it is about + 48 ° C.

Emulsion 5
Emulsion 5 having a nonvolatile content of 47.0% was obtained in the same manner as emulsion 1, except that the composition ratio of the main monomer was changed to methyl methacrylate / butyl acrylate = 256 parts / 171 parts.
The calculated glass transition temperature (Tg) of the copolymer composed of this main monomer composition (methyl methacrylate / butyl acrylate = 256 parts / 171 parts = 60/40 (% by weight)) is obtained by adding the Tg of each homopolymer to +105. When it is set to ° C and -52 ° C, it is about + 21 ° C.

Emulsion 6
Emulsion 6 having a non-volatile content of 47.2% was obtained in the same manner as emulsion 1, except that the composition ratio of the main monomer was changed to methyl methacrylate / butyl acrylate = 214 parts / 213 parts.
The calculated glass transition temperature (Tg) of the copolymer comprising this main monomer composition (methyl methacrylate / butyl acrylate = 214 parts / 213 parts = 50/50 (% by weight)) is obtained by adding the Tg of each homopolymer to +105. When it is set to ° C and -52 ° C, it is about + 6 ° C.

Production example of emulsion resin powder
Emulsion resin powder 1
Emulsion resin powder 1 was obtained by adjusting the nonvolatile content of emulsion 1 to 35% and spray drying at 150 ° C. with a nozzle type spray dryer using a heat source as hot air. The apparent weight average particle diameter of the resin powder 1 was about 36 μm.

Emulsion resin powder 2-5
Emulsion resin powders 2 to 5 were obtained in the same manner as emulsion resin powder 1 except that emulsion 1 was changed to emulsions 2 to 5. The particle diameters of these resin powders 2, 3, 4, and 5 were about 53 μm, about 40 μm, about 26 μm, and about 31 μm, respectively.

Emulsion resin powder 6
An emulsion resin powder 6 was obtained in the same manner as the emulsion resin powder 1 except that the emulsion 1 was changed to the emulsion 6.
However, in the case of the resin powder 6, since the calculated glass transition temperature (Tg) of the copolymer is as low as + 6 ° C., the resin powder 6 is likely to be hardened during storage. Thus, resin powder 6 was obtained by spray drying in the presence of calcium carbonate (“Hydrocarb” / trade name; Plus Staufa (PLUSS-STAUFER)) as an anti-caking agent during spray drying. The amount of the anti-caking agent contained in the resin powder is about 10%, and the apparent weight average particle diameter of the resin powder 6 is about 150 μm.
The compositions of the above emulsion resin powders 1 to 6 are summarized in Table 1.

Vehicle Production Example-1
In a four-necked flask equipped with a condenser, thermometer and stirrer, 400 parts of KG-1829 (Arakawa Chemical Co., Ltd.) as rosin-modified phenol resin, 350 parts of soybean white oil as vegetable oil, 100 parts of tung oil, aliphatic carbonization After 140 parts of AF5 solvent (manufactured by Nippon Oil Co., Ltd.) as a hydrogen solvent was charged and mixed, the temperature was raised to 200 ° C. and heat polymerization was performed for 1 hour to obtain a vehicle.

Example 1 (OP varnish-1)
85 parts of the vehicle obtained in Production Example-1, 1 part of emulsion resin powder 1, 8 parts of AF5 solvent (manufactured by Nippon Oil Corporation), 2 parts of processed starch as an anti-set-off agent, as a metal dryer One part of manganese naphthenate was mixed and kneaded with a three-roll mill to obtain OP varnish for flat printing (OP varnish-1).

Example 2 (OP Varnish-2)
An OP varnish for flat printing (OP varnish-2) was obtained in the same manner as in Example 1 except that the emulsion resin powder 1 was replaced with 2 parts.

Example 3 (OP Varnish-3)
An OP varnish for flat printing (OP varnish-3) was obtained in the same manner as in Example 1 except that the emulsion resin powder 1 was replaced with 4 parts.

Examples 4-8 (OP varnish-4-8)
An OP varnish for flat printing (OP varnish-4 to 8) was obtained in the same manner as in Example 2 except that the emulsion resin powder 1 was replaced with the emulsion resin powders 2 to 6, respectively.

Comparative Example 1 (OP varnish-9)
Except that the emulsion resin powder 1 of Example 1 was removed, an OP varnish for flat printing (OP varnish-9) was obtained in the same manner as in Example 1.

  Using the OP varnishes obtained in the above Examples and Comparative Examples, printing was performed by the following printing method, and the items described below were evaluated.

Printing method-1
Using OP varnishes obtained in Examples 1 to 8 (OP varnishes 1 to 8) and Comparative Example 1 (OP varnish-9), Tokuhishi Art (Mitsubishi Paper Co., Ltd.), JET Star ( Using two types (manufactured by Nippon Paper Industries Co., Ltd.), the color was developed and printed (OP varnish color spread: 0.10 ml) with a RI tester based on JISK5701 (manufactured by Ishikawajima Seisakusho). After leaving at room temperature for 1 day, it was subjected to the test (underlying ink: GP Aplus SOY black EX-N / sheet-fed process black ink / manufactured by Naigai Ink Manufacturing Co., Ltd., color development: 0.1125 ml). The results are shown in Table 2.
In addition, the particle diameter of the resin powder dispersed and dispersed in the OP varnish layer when the OP varnishes of Examples 1 to 8 (OP varnishes 1 to 8) were printed on JET star paper is expressed as OP varnish. Example 1 is 8.8 times, Example 2 is 12.2 times, Example 3 is 11.5 times, Example 4 is 9 times, Example 5 is 6.9 times the thickness of the layer, Example 6 was 7.5 times, Example 7 was 14.9 times, and Example 8 was 17.5 times.

Printing method-2
Using the OP varnish obtained in Examples 1 to 8 (OP varnish-1 to 8) and Comparative Example 1 (OP varnish-9), using a notebook cover special sheet (made by Oji Paper Co., Ltd.) as the paper. And a Lislon printing machine (manufactured by Komori Corporation). After leaving at room temperature for 1 day, it was subjected to the test (printing speed: 4000 to 6000 sheets / hour). The results are shown in Table 3.

Printing method-3
Using the OP varnish obtained in Examples 1 to 8 (OP varnish-1 to 8) and Comparative Example 1 (OP varnish-9), using OK top coat (made by Oji Paper Co., Ltd.) as the paper, Printed with a Mitsubishi Diamond 4-color machine (Mitsubishi Heavy Industries, Ltd.). After being left at room temperature for 1 day, it was subjected to the test (printing speed: 7000 to 8000 sheets / hour). The results are shown in Table 4.

Glossiness The 60 degree gloss of each paper was measured with a Minolta gloss meter GM-60. The gloss increase / decrease rate (%) was evaluated by setting the gloss value of OP Varnish-9 (Comparative Example 1) to which no emulsion resin powder was added as 100.

Fingerprint adhesion resistance test method and evaluation method The paper on which OP varnish was printed was touched with a thumb or forefinger, and the adhesion level of the fingerprint was visually evaluated. The OP varnish-9 (Comparative Example 1) to which no emulsion resin powder was added was used as the standard for the lowest evaluation, and was evaluated as follows.
Evaluation method: sufficiently good anti-fingerprint adhesion (much better than Comparative Example 1);
Good fingerprint resistance (better than Comparative Example 1);
Slightly poor fingerprint resistance (slightly better than Comparative Example 1);
Bad fingerprint resistance (equivalent to Comparative Example 1)

Test method for anti-set-off and evaluation standard printing method-2 and 3 sheets of paper are piled up, placed under a load equivalent to 5000 and left at room temperature for 24 hours. Evaluation was made according to the following criteria.
Evaluation criteria: Set-off prevention is sufficiently good;
Good set-off prevention; ○
Slightly poor prevention of set-off; △
Poor set-off prevention property; ×
In printing method-1, five sheets of 4 × 5 cm square printed paper were stacked and tested in the same manner with a weight of 1 kg.

  As shown in Tables 2 to 4, the printed surfaces according to Examples 1 to 8 are improved in gloss, anti-fingerprint property and anti-set-off property as compared with Comparative Example 1. In particular, the glossiness of the printed surface according to Example 5 using the copolymer emulsion resin powder 3 containing styrene, which is an aromatic vinyl monomer, as a copolymerization component is significantly improved.

  The composition for a flat printing liquid of the present invention can be used as an additive to be added to a conventional oxidation polymerization dry OP varnish or ink. Further, according to the lithographic printing liquid of the present invention, the gloss of the printing paper surface is improved, the anti-set-off property and the anti-blocking property are improved, and the anti-fingerprint property is improved. Can be suitably used for the purpose of increasing the commercial value of the product. Moreover, since the existing flat printing press can be used as it is, the applicability is high. Furthermore, since the surface water repellency and waterproofness of the printing paper surface on which the flat printing liquid of the present invention is printed are improved, it is suitable for printing products that are used or stored in a high humidity environment or an environment where condensation occurs. . For example, it can be suitably used for labeling sake bottles, boxes containing sake bottles, and packaging frozen foods.

Claims (9)

An acrylic resin containing a resin powder of a synthetic resin emulsion which is dispersed and stabilized by a water-soluble polymer , the water-soluble polymer is a polyvinyl alcohol resin, and the resin of the synthetic resin emulsion has a glass transition temperature of −5 ° C. or higher. A composition for a lithographic printing liquid, which is a copolymer. Polyvinyl alcohol resins are, 1 to active hydrogen and / or side chains, flat printing fluid composition of claim 1, wherein the polyvinyl alcohol-based resin having a 1,2-diol bond. The lithographic printing liquid composition according to claim 1 or 2, wherein the acrylic copolymer contains an aromatic vinyl monomer as a copolymerization component. The composition for a flat printing liquid according to claim 3, wherein the aromatic vinyl monomer is contained in an amount of 10% by weight or more based on the entire copolymerization component. The apparent weight average particle diameter of the resin powder of the synthetic resin emulsion is 5 to 200 µm, The composition for a flat printing liquid according to any one of claims 1 to 4 . A flat printing liquid comprising the composition for a flat printing liquid according to any one of claims 1 to 5 and a vehicle. The resin powder having a particle diameter of 2 to 20 times the thickness of the printed layer when printed on the substrate, wherein the resin powder is present in the printed layer formed on the substrate. 6. The flat printing liquid according to 6 . The flat printing liquid according to claim 6 or 7, wherein the content of the resin powder of the synthetic resin emulsion is 0.3 to 10% by weight based on the whole liquid. The flat printing liquid according to any one of claims 6 to 8, which is an overprint varnish or an ink.