Ink for screen printing and printed matter

Abstract

To provide ink for screen printing which is excellent in low temperature temporal stability, leveling property, moisture resistant adhesion and transferability, and a printed matter.SOLUTION: Ink for screen printing contains a binder resin and an organic solvent, wherein the binder resin contains a vinyl chloride copolymer resin and an acrylic resin (excluding the vinyl chloride copolymer resin), the acrylic resin contains an acrylic resin (a) which has a methyl methacrylate-derived constitutional unit and a weight average molecular weight of 10,000-80,000, and the organic solvent contains a cyclic ketone-based organic solvent (A).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an ink for screen printing and a printed matter thereof.

Background Art

[0002] Conventionally, screen printing inks are used in various applications such as for stickers, cards, automotive meters, nameplates, etc., and environmental suitability such as humidity resistance is required. After printing the screen printing ink on a substrate, it is generally used in a form where a surface protection agent such as an overcoat agent is applied.

[0003] For example, as a screen printing ink, an ink using a polyester resin as a binder resin for a polyester substrate (polyethylene terephthalate substrate) is used. On the other hand, various substrates are used for screen printing. For example, polyester-based inks may lack adhesion to substrates such as vinyl chloride substrates and pigment dispersibility.

[0004] For example, Patent Document 1 discloses a printing ink using a vinyl chloride-vinyl acetate copolymer and an acrylic resin as binder resins. However, in the ink described in the invention, only low-boiling organic solvents are used as organic solvents, and there are concerns about poor printing suitability when performing screen printing. In addition, there is a concern about insufficient adhesion to the substrate due to a shortage of the amount of binder resin in the ink.

[0005] Also, for example, Patent Document 2 discloses a screen printing ink using a vinyl chloride-vinyl acetate copolymer and an acrylic resin as binder resins. However, the molecular weight of the acrylic resin is large, which may affect the stability of the ink over time, especially at low temperatures, the leveling property, and the transfer property in screen printing.

[0006] Therefore, no screen printing ink that satisfies printing suitability such as low-temperature stability over time, leveling property, transfer property, and moisture-resistant adhesion has been reported.

Prior Art Documents

Patent Document

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to provide a screen printing ink and a printed matter that are excellent in low-temperature stability over time, leveling property, moisture-resistant adhesion property, and transfer property.

Means for Solving the Problems

[0009] As a result of intensive research, the present inventors have found that the above problems can be solved and have completed the present invention.

[0010] That is, the present invention relates to a screen printing ink containing a binder resin and an organic solvent, wherein the binder resin contains a vinyl chloride copolymer resin and an acrylic resin (excluding the case where it is the vinyl chloride copolymer resin), the acrylic resin contains an acrylic resin (a) having a structural unit derived from methyl methacrylate and having a weight average molecular weight of 10,000 to 80,000, and the organic solvent contains a cyclic ketone-based organic solvent (A).

[0011] Further, the present invention relates to the above screen printing ink containing 25 to 45% by mass of the binder resin based on the total mass of the binder resin and the organic solvent.

[0012] Further, the present invention relates to the above screen printing ink containing 20 to 80% by mass of the cyclic ketone-based organic solvent (A) based on the total mass of the organic solvent.

[0013] Further, in the present invention, the organic solvent further contains an organic solvent (B) having a boiling point of 120 to 250°C, and the organic solvent (B) contains at least one selected from the group consisting of glycol ether-based organic solvents, ester-based organic solvents, aliphatic-based organic solvents, aromatic-based organic solvents, and alcohol-based organic solvents. The present invention relates to the ink for screen printing described above.

[0014] Further, the present invention relates to the ink for screen printing described above, wherein the vinyl chloride copolymer resin contains 2 to 10% by mass of vinyl alcohol units based on the total mass of the vinyl chloride copolymer resin.

[0015] Further, the present invention relates to the ink for screen printing described above, which further contains an antifoaming agent that is a non-silicone-based compound.

[0016] Further, the present invention relates to a printed matter having a printed layer made of the above-described ink for screen printing on a substrate.

[0017] Further, the present invention relates to the above-described printed matter, wherein the substrate is a label film having a polyvinyl chloride layer.

Effects of the Invention

[0018] According to the present invention, it has become possible to provide an ink for screen printing and a printed matter that are excellent in low-temperature stability over time, leveling property, moisture-resistant adhesion, and transfer property.

Modes for Carrying Out the Invention

[0019] Hereinafter, the present invention will be described in detail. The ink for screen printing may be simply abbreviated as "printing ink" or "ink", which are synonymous. Further, the film formed by printing the ink for screen printing may be referred to as a "printed layer", "ink film", or "ink layer", which are synonymous.

[0020] The ink for screen printing of the present invention is an ink for screen printing containing a binder resin and an organic solvent, The binder resin contains a vinyl chloride copolymer resin and an acrylic resin (excluding the case where it is the vinyl chloride copolymer resin), The acrylic resin includes an acrylic resin (a) having a structural unit derived from methyl methacrylate and having a weight average molecular weight of 10,000 to 80,000, The organic solvent contains a cyclic ketone-based organic solvent (A), and relates to an ink for screen printing.

[0021] <Binder resin> In the present invention, the binder resin refers to a resin that can function as a binder in an ink for screen printing, and is preferably a thermoplastic resin. Further, the binder resin includes a vinyl chloride copolymer resin such as a vinyl chloride-vinyl acetate copolymer resin, and an acrylic resin. The ink for screen printing preferably contains 25 to 45% by mass of the binder resin, more preferably 28 to 43% by mass, and still more preferably 30 to 40% by mass, based on the total of the binder resin and the organic solvent contained in the ink. This is to improve the stability over time at low temperatures.

[0022] The vinyl chloride copolymer resin and the acrylic resin preferably contain 50% by mass or more of the binder resin, more preferably 80% by mass or more. The mass ratio of the vinyl chloride copolymer resin to the acrylic resin is preferably 95:5 to 40:60, and more preferably 90:10 to 50:50.

[0023] The binder resin may contain resins other than the vinyl chloride-vinyl acetate copolymer resin and the acrylic resin. For example, styrene resins, polyurethane resins, polyepoxy resins, polyester resins, rosin resins, styrene-maleic acid resins, dammar resins, polycarbonate resins, rosin-modified maleic acid resins, rosin ester resins, terpene resins, and other thermoplastic resins can be mentioned. These binder resins may be used in combination as long as the effects of the present invention are not impaired.

[0024] <Vinyl chloride copolymer resin> The vinyl chloride copolymer resin is not particularly limited as long as it contains a structural unit derived from vinyl chloride and a structural unit derived from other monomers. Among them, a copolymer resin containing vinyl alcohol units is preferable. The vinyl chloride copolymer resin preferably contains 2 to 10% by mass of vinyl alcohol units based on the total amount of the vinyl chloride copolymer resin. The content of the vinyl alcohol units is more preferably 3 to 9% by mass, and even more preferably 4 to 8% by mass. This is because the pigment dispersibility is improved. In the present invention, the vinyl alcohol unit or the vinyl alcohol-derived unit refers to a structural unit that appears to be derived from a vinyl alcohol monomer regardless of the production process (mostly saponification of a structural unit derived from vinyl acetate) when distinguishing the structural units of the copolymer derived from vinyl monomers. Further, the vinyl chloride copolymer resin is preferably a vinyl chloride-vinyl acetate copolymer resin and / or a vinyl chloride-acrylic copolymer resin. It is more preferable that the vinyl chloride-vinyl acetate copolymer resin and / or the vinyl chloride-acrylic copolymer resin have vinyl alcohol units.

[0025] <Vinyl chloride-vinyl acetate copolymer resin> The vinyl chloride-vinyl acetate copolymer resin is a copolymer of vinyl chloride and vinyl acetate, and preferably has a weight average molecular weight of 5,000 to 100,000, and more preferably 20,000 to 70,000. The structural unit derived from the vinyl acetate monomer in 100% by mass of the solid content of the vinyl chloride-vinyl acetate copolymer resin is preferably 1 to 10% by mass, more preferably 1 to 7% by mass, and even more preferably 1 to 5% by mass. The structural unit derived from the vinyl chloride monomer is preferably 75 to 95% by mass. In this case, the solubility in an organic solvent is improved, and the adhesion to a substrate, film physical properties, pigment dispersibility (including stability over time), etc. are good. In addition, in order to improve the solubility in an organic solvent, those containing a hydroxyl group derived from vinyl alcohol by saponification reaction or copolymerization are more preferable, and the hydroxyl value is preferably 20 to 200 mgKOH / g. Further, the glass transition temperature is preferably 50°C to 90°C, and more preferably 60 to 85°C.

[0026] <Vinyl chloride-acrylic copolymer resin> The vinyl chloride-acrylic copolymer resin is mainly composed of a copolymer resin of a vinyl chloride monomer and an acrylic monomer. As the acrylic monomer, the same ones as those described below can be used, but in order to improve the adhesiveness to the substrate and the solubility in an organic solvent, it is preferable to contain a (meth)acrylic acid hydroxyalkyl ester as a structural unit. The acrylic monomer may be incorporated into the main chain of polyvinyl chloride in a block or random manner, or may be graft-polymerized to the side chain of polyvinyl chloride. The vinyl chloride-acrylic copolymer resin preferably has a weight average molecular weight of 10,000 to 100,000, and more preferably 30,000 to 70,000. Further, the hydroxyl value is preferably 20 to 200 mgKOH / g, the glass transition temperature is preferably 50°C to 90°C, and more preferably 60 to 85°C.

[0027] <Acrylic resin> The acrylic resin used in the present invention has a structural unit derived from methyl methacrylate and contains an acrylic resin (a) having a weight average molecular weight of 10,000 to 80,000. In addition, it does not include the case of being the vinyl chloride copolymer resin. In the present invention, the "acrylic resin" is a resin having an acrylic monomer as a structural unit and not containing a structural unit derived from vinyl chloride. The acrylic resin preferably contains 50% by mass or more of the structural units derived from the acrylic monomer in the whole acrylic resin. The acrylic resin (a) having a structural unit derived from methyl methacrylate and having a weight average molecular weight of 10,000 to 80,000 is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and still more preferably 90 to 100% by mass based on the total mass of the acrylic resin. The acrylic resin (a) having a structural unit derived from methyl methacrylate strengthens the film of the ink layer, and the weight average molecular weight of the acrylic resin (a) being 10,000 to 80,000 enables good printing suitability. Furthermore, since the organic solvent contains a cyclic ketone-based organic solvent (A), the solubility of the vinyl chloride copolymer resin and the acrylic resin (a) is improved, and when these requirements are met, the pigment dispersibility is also good, and the properties are improved. The content of the structural unit derived from methyl methacrylate is still preferably 1 to 70% by mass, and more preferably 5 to 60% by mass of the total mass of the acrylic resin (a). This is to improve the good adhesion to the substrate. Also, it is necessary for the weight average molecular weight to be 10,000 to 80,000, and the weight average molecular weight is preferably 20,000 to 75,000. Also, the glass transition temperature of the acrylic resin (a) is preferably 60 to 120°C, and more preferably 70 to 110°C. This is to improve the blocking resistance of the printing layer composed of the printing ink. The acid value of the acrylic resin (a) is preferably 25 mgKOH / g or less, and more preferably 20 mgKOH / g or less. This is to improve the stability over time. The "acrylic monomer" means a monomer having an acrylic group or a methacryloyl group, and "methacryl and / or acrylic" may be collectively referred to as "(meth)acrylic" for short. Also, "methacrylate and / or acrylate" may be collectively referred to as "(meth)acrylate" for short.

[0028] The acrylic monomers that constitute the acrylic resin or acrylic resin (a) are listed below, but are not limited thereto. Preferred examples of the acrylic monomers include alkyl (meth)acrylates and hydroxyl group-containing alkyl (meth)acrylates. The acrylic monomers may be used alone or in combination of two or more. Among the following listed acrylic monomers, it is more preferable to include methyl methacrylate. Further, it is preferable to include structural units derived from alkyl methacrylate (alkyl group having 2 or more carbon atoms) and / or hydroxyalkyl methacrylate. It is still more preferable to include butyl (meth)acrylate and / or 2-hydroxyethyl (meth)acrylate.

[0029] Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, methylcyclohexyl (meth)acrylate, bornyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate and the like. Among these, it is preferable that the alkyl group has 2 to 8 carbon atoms, and butyl (meth)acrylate is more preferable in terms of easily obtaining good adhesion to the base material.

[0030] The acrylic monomer may contain a hydroxyl group-containing alkyl (meth)acrylate. For example, hydroxyalkyl esters of (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, glycol mono(meth)acrylates such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, caprolactone-modified (meth)acrylate, hydroxyethylacrylamide, etc. may be mentioned. Among these, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred.

[0031] <Cyclic ketone-based organic solvent (A)> As the cyclic ketone-based organic solvent (A), a solvent containing a 5- to 7-membered cyclic ketone structure in the molecule is preferred. Examples of the 5-membered cyclic ketone solvent include cyclopentanone, 2-methyl-2-cyclopenten-1-one, 2-methylcyclopentanone, 3-methylcyclopentanone, 2-ethylcyclopentanone, 3-ethylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, etc. Examples of the 6-membered cyclic ketone solvent include cyclohexanone, isophorone, 2-cyclohexen-1-one, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2-dimethylcyclohexanone, etc. Examples of the 7-membered cyclic ketone solvent include cyclopeptanone, 2-cyclopeptan-1-one, etc. Preferably, the total mass of the organic solvent contains 20 to 80% by mass of the cyclic ketone-based organic solvent (A), more preferably 30 to 70% by mass, and still more preferably 40 to 60% by mass. This is because the solubility in the resin is improved. The boiling point of the cyclic ketone-based organic solvent (A) is preferably 120 to 250°C, more preferably 130 to 230°C.

[0032] <Organic solvent (B) having a boiling point of 120 to 250°C> As one embodiment, it is also preferable that the ink for screen printing contains an organic solvent (B) having a boiling point of 120 to 250°C. Specifically, it contains at least one selected from the group consisting of glycol ether-based organic solvents, ester-based organic solvents, aliphatic-based organic solvents, aromatic-based organic solvents, and alcohol-based organic solvents (the organic solvent (B) does not contain the above cyclic ketone-based organic solvent (A)). The organic solvent (B) is preferably contained in an amount of 30 to 70% by mass, more preferably 40 to 60% by mass, based on the total amount of the organic solvents constituting the liquid medium of the ink for screen printing. This is because the solubility in the resin is improved.

[0033] Examples of the glycol ether-based organic solvent include ethylene glycol dibutyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethoxymethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, and the like.

[0034] Examples of ester-based organic solvents include gamma-butyrolactone, cellosolve acetate, propylene glycol monomethyl ether acetate, ethylene glycol diacetate, ethylene glycol monoacetate, ethylene glycol monobutyl ether acetate, diethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene carbonate, and the like.

[0035] Examples of aliphatic organic solvents include normal paraffin solvents, isoparaffin solvents, cycloparaffin solvents, and the like.

[0036] Examples of aromatic organic solvents include, for example, toluene, xylene, ethylbenzene, naphthalene, tetralin, solvent naphtha, and in addition, as solvents rich in aromatics, such as Swasol (manufactured by Cosmo Oil Co., Ltd., Maruzen Petrochemical Co., Ltd.), Solvesso (manufactured by ExxonMobil Corporation), Cactus Fine (manufactured by Japan Energy Corporation), and the like.

[0037] Examples of alcohol-based organic solvents include diacetone alcohol, N-amyl alcohol, methyl isobutyl carbinol, n-butanol, 3-methoxy-3-methyl-1-butanol, ethylene glycol, propylene glycol, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, hexylene glycol, 1,5-pentanediol, and the like.

[0038] Among the above, the boiling points of typical ones are shown below. Isophorone: boiling point 215.2 °C 3-Methylcyclopentanone: boiling point 145 °C Ethylene glycol monobutyl ether: boiling point 168.4 °C Gamma-butyrolactone: boiling point 204 °C Solvent A: aliphatic organic solvent (component mineral spirit), boiling point 160 - 200 °C Diacetone alcohol: boiling point 166 °C These can be used in combination and can be in any ratio.

[0039] <Pigment> The screen printing ink of the present invention may be used in combination with commonly used organic pigments, inorganic pigments, extender pigments, etc. As organic pigments, azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, diketopyrrolopyrrole-based, isoindoline-based pigments and the like are suitable, but are not limited thereto. C.I pigments described in the Color Index can be used as appropriate. Examples of inorganic pigments include titanium oxide, carbon black, aluminum paste, mica, bronze powder, chrome vermilion, lead yellow, cadmium yellow, cadmium red, ultramarine blue, dark blue, red iron oxide, iron black, and the like. As extender pigments, it is preferable to use silica, alumina, talc, calcium carbonate, precipitated barium, etc. The pigment is preferably contained in an amount of 0.1 to 50% by mass, more preferably 5 to 45% by mass, based on the total amount of the screen printing ink.

[0040] <Antifoaming agent> The screen printing ink of the present invention preferably contains an antifoaming agent. The content is preferably 0.1 to 5% by mass, more preferably 0.3 to 4% by mass, based on the total amount of the screen printing ink. Examples of the compound constituting the antifoaming agent include acrylic resins, vinyl ether resins, butadiene resins, silicone resins, fluorine-based resins, and modified resins thereof (however, the above binder resins are not included). The antifoaming agent is preferably a non-silicone-based resin, and preferably contains at least one resin selected from acrylic resins, vinyl ether resins, and butadiene resins. For example, commercially available antifoaming agents of this type include the BYK series (manufactured by Big Chemie Japan) and the Florens series (manufactured by Kyoeisha Chemical Co., Ltd.).

[0041] <Leveling agent> The screen printing ink of the present invention preferably further contains a leveling agent. The content is preferably 0.1 to 1% by mass based on the whole screen printing ink. The compound constituting the leveling agent is preferably an acrylic resin and / or a silicone resin (however, the above binder resin is not included). For example, commercially available such leveling agents include the Polyflow series (manufactured by Kyoeisha Chemical Co., Ltd.). These may be used alone or in combination of two or more.

[0042] <Other additives> Also, if necessary, additives such as a dispersant, a wetting and penetrating agent, an anti-skinning agent, an ultraviolet absorber, an antioxidant, a crosslinking agent, a preservative, a fungicide, a viscosity modifier, and a pH modifier can be appropriately blended within a range not inhibiting the object of the present invention. Among them, it is preferable to use a dispersant. This is for improving the jet-black feeling of the printed matter. As the dispersant, an acidic dispersant is preferable.

[0043] <Manufacture of screen printing ink> The screen printing ink of the present invention can be produced by a conventionally known dispersion method as appropriate. For example, a required amount of a binder resin, a pigment, an organic solvent, and an additive are mixed, stirred well with a stirrer, etc., and then can be produced by a disperser such as a three-roll mill, a paint shaker, an attritor, or a sand mill.

[0044] <Substrate> The base material used for forming the printed matter in the present invention is not particularly limited, and examples include inorganic base materials such as glass, polyester base materials such as polyethylene terephthalate, polyolefin base materials such as polyethylene, polypropylene, ethylene-vinyl acetate, and others, nylon base materials such as polyamide, acrylic base materials, polyvinyl chloride base materials, polycarbonate base materials, polyurethane base materials, resin base materials such as epoxy base materials. These laminated bodies may also be used. Further, a vapor-deposited base material obtained by vapor-depositing an inorganic compound such as silica, alumina, or aluminum on the base material can also be used, and furthermore, the vapor-deposited surface may be subjected to a coating treatment with polyvinyl alcohol or the like. Also, corona treatment, frame treatment, or stretching treatment may be performed. Among the above, a polyvinyl chloride base material composed only of a polyvinyl chloride layer, or a film base material having a polyvinyl chloride layer as the outermost layer, which is a laminated body having a polyvinyl chloride layer, is preferable.

[0045] <Printed matter> The printed matter of the present invention refers to a material in which a printing layer made of screen printing ink is formed on a base material by any printing method. The printing method is screen printing, and it is preferable that the printing conditions use a resin material such as nylon or polyester for the printing plate and a resin material such as stainless steel for the printing machine, such as a cylinder press printing machine or a semi-automatic printing machine.

[0046] <Label> One embodiment of the present invention, a label, will be described. For example, if a film base material having a polyvinyl chloride layer is used as the above base material and screen printing is performed on the polyvinyl chloride layer, it can be suitably used as a label. The label (printed matter) may be in a form where an adhesive is applied to the printed matter and attached to an article, or may be in a form where it is held on the article by heat shrinkage without using an adhesive like a shrink label, or may be in a form where only the end of the printed matter is subjected to adhesive or heat sealing and wound around the article like a body wrap label. Any form is preferable.

Example

[0047] Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited in any way by the following examples. In the present invention, unless otherwise specified, "parts" represents "parts by mass" and "%" represents "% by mass".

[0048] <Measurement of various numerical values> (Acid value) It was measured according to the method described in JIS K0070. (Molecular weight and molecular weight distribution) The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were measured by GPC (gel permeation chromatography) and determined as the converted molecular weight using polystyrene as a standard substance. GPC apparatus: Shodex GPC-104 manufactured by Showa Denko KK Columns: The following columns were connected in series and used. Two Shodex LF-404 manufactured by Showa Denko KK Shodex LF-G manufactured by Showa Denko KK Detector: RI (differential refractometer) Measurement conditions: Column temperature 40°C Eluent: Tetrahydrofuran Flow rate: 0.3 mL / min (Glass transition temperature) The glass transition temperature (Tg) was determined by DSC (differential scanning calorimetry). The measuring instrument used was DSC8231 manufactured by Rigaku Corporation. The measuring temperature range was -70 to 250°C, the heating rate was 10°C / min, and the midpoint between the endothermic start temperature and the end temperature based on the glass transition in the DSC curve was taken as the glass transition temperature.

[0049] <Example 1>[Preparation of ink S1 for screen printing] As the binder resin, 25 parts of vinyl chloride-vinyl acetate copolymer resin (Solvain C, 0% vinyl alcohol, 87% by mass of vinyl chloride, 13% by mass of vinyl acetate, glass transition temperature 70°C, manufactured by Nissin Chemical Industry Co., Ltd.), 5 parts of Dianal BR-77 (acrylic resin manufactured by Mitsubishi Chemical Corporation, 20-50% by mass of the constituent unit derived from methyl methacrylate, weight average molecular weight 60,000, acid value 18 mgKOH / g, glass transition temperature 80°C, manufactured by Mitsubishi Chemical Corporation), 29 parts of cyclic ketone-based organic solvent cyclohexanone (boiling point 155.6°C) as the organic solvent, 29 parts of aromatic-based organic solvent Swazol 1000 (component C9 aromatic hydrocarbon, manufactured by Maruzen Petrochemical Co., Ltd., boiling point 167°C), 2 parts of BYK-057 (butadiene copolymer, manufactured by BYK-Chemie Japan) as the non-silicone-based antifoaming agent, and 10 parts of pigment (C.I. Pigment Blue 15:4) were uniformly mixed using a mixer rotary stirrer, and then passed through a three-roll disperser twice to prepare screen printing ink (S1).

[0050] <Examples 2 to 22, Comparative Examples 1 to 6>[Preparation of Screen Printing Inks S2 to S22, T1 to T6] Screen printing inks were prepared in the same manner as in Example 1. The abbreviations in Tables 1 and 2 are shown below. Also, the numerical values in the tables represent "parts" unless otherwise specified, and blanks indicate that they were not used. Dianal BR-87: Acrylic resin having a constituent unit derived from methyl methacrylate as a constituent unit, manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 25,000, acid value 10 mgKOH / g, glass transition temperature 105°C Paraloid B66: Acrylic resin having a constituent unit derived from methyl methacrylate as a constituent unit, manufactured by The Dow Chemical Company, weight average molecular weight 70,000, acid value 3.5 mgKOH / g, glass transition temperature 50°C Solvain TA3: Vinyl chloride-acrylic copolymer resin manufactured by Nissin Chemical Company, 83% by mass of vinyl chloride unit, glass transition temperature 65°C Solvain A: Vinyl chloride-vinyl acetate copolymer resin manufactured by Nissin Chemical Company, 92% by mass of vinyl chloride unit, 3% by mass of vinyl alcohol unit, glass transition temperature 76°C Solvayne TAO: Vinyl chloride - vinyl acetate copolymer resin manufactured by Nissin Chemical Industry Co., Ltd., 91% by mass of vinyl chloride units, 7% by mass of vinyl alcohol units, glass transition temperature 77°C Solvayne TA5R: Vinyl chloride - vinyl acetate copolymer resin manufactured by Nissin Chemical Industry Co., Ltd., 88% by mass of vinyl chloride units, 11% by mass of vinyl alcohol units, glass transition temperature 78°C In addition, all of the above vinyl chloride copolymer resins have a weight - average molecular weight in the range of 30,000 to 70,000. Shin -etsu silicone KF - 96 - 1000CS: Silicone - based defoaming agent (manufactured by Shin -etsu Chemical Co., Ltd.) Dianal BR - 80: Acrylic resin manufactured by Mitsubishi Chemical Corporation, weight - average molecular weight 100,000 Acrylic resin A: Acrylic resin with a weight - average molecular weight of 8000 and a glass transition temperature of 70°C having a structural unit derived from methyl methacrylate Isophorone: Boiling point 215.2°C 3 - Methylcyclopentanone: Boiling point 145°C Ethylene glycol monobutyl ether: Boiling point 168.4°C Gamma - butyrolactone: Boiling point 204°C Solvent A: Aliphatic organic solvent (component mineral spirit), boiling point 160 - 200°C Diacetone alcohol: Boiling point 166°C Bylon 200: Amorphous polyester resin manufactured by Toyobo Co., Ltd.

[0051] <Printing with Screen - printing Ink S1> Using a label film having a polyvinyl chloride layer as a substrate (manufactured by Oji Tack Co., Ltd., PVCW80 / F93 / YW16, 80μm), Screen - printing Ink S1 for the above - mentioned screen printing was screen - printed in a pattern using a screen printing plate (manufactured by NBC Mesh Tech Co., Ltd., L - SCREEN, 100 - 035 / 255PW) on this substrate to produce a screen - printed product.

[0052] <Examples 1 - 22, Comparative Examples 1 - 6>[Printing with Screen - printing Inks S1 - S22, T1 - T6] The printed materials were produced in the same manner as in Example 1, except that the screen printing ink S1 used in Example 1 was changed to the screen printing inks described in Table 2.

[0053] <Evaluation of Screen Printing Ink and Its Printed Material> The following evaluations were performed on the screen printing inks and printed materials obtained in the above Examples and Comparative Examples. The evaluation results are shown in Table 1 and Table 2.

[0054] <Low-Temperature Aging Stability> The screen printing inks obtained in Examples 1 to 22 and Comparative Examples 1 to 6 were each held at -5°C for 5 days. The change in the viscosity value before and after holding was evaluated. The criteria for the evaluation results were as follows. A (excellent): The viscosity change is less than 10%. B (good): The viscosity change is 10% or more and less than 20%. C (poor): The viscosity change is 20% or more. Note that the industrially applicable levels are A and B.

[0055] <Evaluation of Levelling Property> The evaluation was performed using the printed materials obtained in Examples 1 to 22 and Comparative Examples 1 to 6. The criteria for the evaluation results were as follows. "Printing unevenness" refers to a state where the color density of the printed layer is uneven. A (excellent): Less than 5% of the area within the pattern has printing unevenness. B (good): 5% or more and less than 20% of the area within the pattern has printing unevenness. C (poor): 20% or more of the area within the pattern has printing unevenness. Note that the industrially applicable levels are A and B.

[0056] <Moisture Resistance Adhesion> Evaluations were conducted using the printed materials obtained in Examples 1 to 22 and Comparative Examples 1 to 6. After exposing the printed materials to an atmosphere of 40°C and 80% humidity for 24 hours, a pressure-sensitive adhesive tape (Nichiban cellophane tape) with a width of 12 mm was attached to the printed surface, and the appearance state of the printed surface when this was rapidly peeled off was visually judged. The criteria for judging the evaluation results were as follows. A (excellent): The ink film on the printed surface does not peel off at all. B (good): The peeled area of the ink film is 5% or more and less than 20%. C (poor): The peeled area of the ink film is 20% or more. Note that the industrially applicable levels are A and B.

[0057] <Evaluation of transferability> Evaluations were conducted using the screen printing inks obtained in Examples 1 to 22 and Comparative Examples 1 to 6. In the following evaluations, the transfer rate refers to the weighed calculated value of the ink mass transferred per unit area in one printing. The criteria for the evaluation results were as follows. A (excellent): The transfer rate of the printed ink is 90% by mass or more. B (good): The transfer rate of the printed ink is 80% by mass or more and less than 90% by mass. C (poor): The transfer rate of the printed ink is less than 80% by mass. Note that the industrially applicable levels are A and B.

[0058]

Table 1

[0059]

Table 2

[0060] According to the present invention, a screen printing ink and a printed material excellent in low-temperature stability over time, leveling property, moisture-resistant adhesion, and overprinting property can be provided in order to solve the above problems. In Comparative Example 1 of the cyclic ketone-based organic solvent (A), the low-temperature stability over time, leveling property, and transfer property were poor. In Comparative Example 3 with a different type of binder resin, the low-temperature stability over time, leveling property, and moisture-resistant adhesion were poor. In Comparative Example 6 with a high weight-average molecular weight of the acrylic resin, the low-temperature stability over time, leveling property, and transfer property were poor. In Comparative Example 5 with a low weight-average molecular weight of the acrylic resin, the low-temperature stability over time and moisture-resistant adhesion were poor.

Claims

1. An ink for screen printing containing a binder resin and an organic solvent, wherein the binder resin contains a vinyl chloride copolymer resin and an acrylic resin (excluding the case where it is the vinyl chloride copolymer resin), the acrylic resin contains an acrylic resin (a) having a constituent unit derived from methyl methacrylate and a weight average molecular weight of 10,000 to 80,000, the binder resin is contained in an amount of 23.5 to 45% by mass based on the total mass of the binder resin and the organic solvent, the organic solvent contains a cyclic ketone-based organic solvent (A), the cyclic ketone-based organic solvent (A) is contained in an amount of 17.9 to 85% by mass based on the total mass of the organic solvent, the organic solvent further contains an organic solvent (B) having a boiling point of 120 to 250 °C, the organic solvent (B) contains at least one selected from the group consisting of glycol ether-based organic solvents, ester-based organic solvents, aliphatic-based organic solvents, aromatic-based organic solvents, and alcohol-based organic solvents, an ink for screen printing (excluding the case where it is an ink composition used by thermal transfer).

2. The ink for screen printing according to Claim 1, wherein the vinyl chloride copolymer resin contains 2 to 10% by mass of vinyl alcohol units based on the total mass of the vinyl chloride copolymer resin.

3. The ink for screen printing according to Claim 1 or 2, further containing an antifoaming agent which is a non-silicone-based compound.

4. A printed matter having a printing layer made of the ink for screen printing according to Claim 1 on a substrate.

5. The printed matter according to Claim 4, wherein the substrate is a film substrate having a polyvinyl chloride layer.

6. A method for manufacturing a printed matter having a printing layer made of an ink for screen printing, comprising a step of forming a printing layer by screen printing the ink for screen printing on a substrate, the ink for screen printing comprises a binder resin and an organic solvent, the binder resin contains a vinyl chloride copolymer resin and an acrylic resin (excluding the case where it is the vinyl chloride copolymer resin), the acrylic resin contains an acrylic resin (a) having a constituent unit derived from methyl methacrylate and a weight average molecular weight of 10,000 to 80,000, the binder resin is contained in an amount of 23.5 to 45% by mass based on the total mass of the binder resin and the organic solvent, the organic solvent contains a cyclic ketone-based organic solvent (A), The cyclic ketone-based organic solvent (A) is contained in an amount of 17.9 to 85% by mass based on the total mass of the organic solvent, the organic solvent further contains an organic solvent (B) having a boiling point of 120 to 250°C, the organic solvent (B) contains at least one selected from the group consisting of glycol ether-based organic solvents, ester-based organic solvents, aliphatic organic solvents, aromatic organic solvents, and alcohol-based organic solvents, Method for producing a printed matter.

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