JP2022130777A - Ink for screen printing and printed matter - Google Patents

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

The present invention relates to an ink for screen printing and printed matter thereof.

Conventionally, screen printing inks have been used in various forms such as stickers, cards, automobile meters, and nameplates, and environmental suitability such as humidity resistance is required. After printing the ink for screen printing on the substrate, it is common to apply an overcoat agent or the like to protect the surface before use.

For example, as an ink for screen printing, an ink using a polyester resin as a binder resin is used for a polyester base material (polyethylene terephthalate base material). On the other hand, a wide variety of substrates are used for screen printing. For example, polyester-based inks sometimes lack adhesion to vinyl chloride substrates and dispersibility of pigments.

For example, Patent Document 1 discloses a printing ink containing a vinyl chloride-vinyl acetate copolymer and an acrylic resin as a binder resin. However, when screen printing is performed, there is concern about poor printability. In addition, there is concern about adhesion to substrates due to insufficient amount of binder resin in the ink.

Further, for example, Patent Document 2 discloses a screen printing ink using a vinyl chloride-vinyl acetate copolymer and an acrylic resin as a binder resin. May affect stability, leveling in screen printing, transferability, etc.

Therefore, no screen printing ink has been reported that satisfies printability such as low-temperature aging stability, leveling property, transfer property, etc., and moisture-resistant adhesion.

WO2016/121141 pamphlet Japanese Patent Application Laid-Open No. 2004-231805

An object of the present invention is to provide a screen printing ink and a printed matter which are excellent in low-temperature aging stability, leveling property, moisture-resistant adhesion and transfer property.

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

That is, the present invention provides a screen printing ink containing a binder resin and an organic solvent,
The binder resin contains a vinyl chloride copolymer resin and an acrylic resin (excluding the vinyl chloride copolymer resin),
The acrylic resin comprises an acrylic resin (a) having a weight-average molecular weight of 10,000 to 80,000 and having structural units derived from methyl methacrylate,
The screen printing ink, wherein the organic solvent contains a cyclic ketone-based organic solvent (A).

The present invention also relates to the screen printing ink containing 25 to 45% by mass of the binder resin with respect to the total mass of the binder resin and the organic solvent.

The present invention also relates to the screen printing ink containing 20 to 80% by mass of the cyclic ketone-based organic solvent (A) with respect to the total mass of the organic solvent.

Further, in the present invention, the organic solvent further contains an organic solvent (B) having a boiling point of 120 to 250° C.,
The above screen, wherein 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. It relates to printing inks.

The present invention also relates to the above ink for screen printing, wherein the vinyl chloride copolymer resin contains 2 to 10% by mass of vinyl alcohol units relative to the total mass of the vinyl chloride copolymer resin.

The present invention also relates to the above screen printing ink, which further contains an antifoaming agent that is a non-silicone compound.

The present invention also provides a printed material having a print layer formed of the screen printing ink on a base material.

The present invention also relates to the above printed matter, wherein the substrate is a label film having a polyvinyl chloride layer.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a screen printing ink and a printed matter which are excellent in low-temperature aging stability, leveling property, moisture-resistant adhesion property and transfer property.

Although the present invention will be described in detail below, screen printing ink may be abbreviated simply as "printing ink" or "ink", but they have the same meaning. A film printed with screen printing ink is sometimes referred to as a "printing layer", an "ink film" or an "ink layer", but these have the same meaning.

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

<Binder resin>
In the present invention, the binder resin refers to a resin that can function as a binder in the screen printing ink, and is preferably a thermoplastic resin. Binder resins include vinyl chloride copolymer resins such as vinyl chloride-vinyl acetate copolymer resins, and acrylic resins.
The screen printing ink preferably contains 25 to 45% by mass of the binder resin with respect to the total of the binder resin and the organic solvent contained in the ink, and the content is 28 to 43% by mass. is still more preferable, and 30 to 40% by mass is even more preferable. This is because the low temperature aging stability is improved.

The vinyl chloride copolymer resin and the acrylic resin are preferably contained in an amount of 50% by mass or more, more preferably 80% by mass or more, of the binder resin. The mass ratio of the vinyl chloride copolymer resin to the acrylic resin is preferably 95:5 to 40:60, more preferably 90:10 to 50:50.

The binder resin may contain vinyl chloride-vinyl acetate copolymer resin and resin other than acrylic resin, such as styrene-based resin, polyurethane resin, polyepoxy resin, polyester resin, rosin-based resin, styrene-maleic acid resin. , dammar resins, polycarbonate resins, rosin-modified maleic acid resins, rosin ester resins, terpene resins, other thermoplastic resins, and the like, and these binder resins may be used in combination as long as the effects of the present invention are not impaired. .

<Vinyl chloride copolymer resin>
The vinyl chloride copolymer resin is not particularly limited as long as it contains structural units derived from vinyl chloride and structural units derived from other monomers. Among them, a copolymer resin containing a vinyl alcohol unit is preferable. The vinyl chloride copolymer resin preferably contains 2 to 10% by mass of vinyl alcohol units with respect to the entire vinyl chloride copolymer resin. The content of the vinyl alcohol unit is more preferably 3 to 9% by mass, more preferably 4 to 8% by mass. This is because pigment dispersibility is improved. In the present invention, vinyl alcohol units or derived from vinyl alcohol are vinyl alcohol monomers regardless of the production process (mostly saponification of vinyl acetate-derived structural units) when distinguishing the structural units of the copolymer from vinyl monomers. It refers to what can be seen as the constituent unit of origin.
Also, 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.

<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, more preferably 20,000 to 70,000. is more preferred. 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 1 to 5% by mass. is more preferred. The vinyl chloride monomer-derived structural unit is preferably 75 to 95% by mass. In this case, the solubility in organic solvents is improved, and the adhesion to substrates, film physical properties, pigment dispersibility (including aging stability) and the like are improved.
Further, since the solubility in organic solvents is improved, those containing hydroxyl groups derived from vinyl alcohol by saponification reaction or copolymerization are more preferable, and the hydroxyl value is preferably 20 to 200 mgKOH/g. Also, the glass transition temperature is preferably 50°C to 90°C, more preferably 60°C to 85°C.

<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 acrylic monomer as described below can be used. It preferably contains a (meth)acrylic acid hydroxyalkyl ester as a structural unit because it improves adhesiveness and solubility in organic solvents. The acrylic monomer may be incorporated into the main chain of polyvinyl chloride in blocks or randomly, or may be graft-polymerized to the side chains of polyvinyl chloride. The vinyl chloride-acrylic copolymer resin preferably has a weight average molecular weight of 10,000 to 100,000, 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 to 90°C, and more preferably 60 to 85°C.

<Acrylic resin>
The acrylic resin used in the present invention includes acrylic resin (a) having a structural unit derived from methyl methacrylate and having a weight average molecular weight of 10,000 to 80,000. Moreover, it does not include the vinyl chloride copolymer resin. In the present invention, the “acrylic resin” is a resin that contains acrylic monomers as structural units but does not contain vinyl chloride-derived structural units. The acrylic resin preferably contains structural units derived from acrylic monomers in an amount of 50% by mass or more based on the total amount of the acrylic resin.
The acrylic resin (a) having a structural unit derived from methyl methacrylate and having a weight average molecular weight of 10000 to 80000 is preferably 50 to 100% by mass, preferably 70 to 100%, based on the total mass of the acrylic resin. % by mass is more preferable, and 90 to 100% by mass is more preferable.
The acrylic resin (a) has a structural unit derived from methyl methacrylate to strengthen the film of the ink layer, and the weight average molecular weight of the acrylic resin (a) is 10,000 to 80,000 to improve printability. can be done. Furthermore, the organic solvent contains the cyclic ketone-based organic solvent (A), thereby improving the solubility of the vinyl chloride copolymer resin and the acrylic resin (a), and by combining these requirements, the pigment dispersibility is also good. and the characteristics are improved.
The content of the structural unit derived from methyl methacrylate is preferably 1 to 70% by mass, more preferably 5 to 60% by mass of the total mass of the acrylic resin (a). This is because good adhesion to the substrate is improved. Also, the weight average molecular weight must 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, more preferably 70 to 110°C. This is because the blocking resistance of the printing layer made of the printing ink is improved.
The acid value of the acrylic resin (a) is preferably 25 mgKOH/g or less, more preferably 20 mgKOH/g or less. This is because the stability over time is improved.
"Acrylic monomer" means a monomer having an acryl group or a methacryloyl group, and "methacryl and/or acryl" may be collectively abbreviated as "(meth)acryl". In addition, "methacrylate and/or acrylate" may be collectively abbreviated as "(meth)acrylate".

The acrylic monomers constituting the acrylic resin or the acrylic resin (a) are listed below, but are not limited to these. Suitable acrylic monomers include alkyl (meth)acrylates and hydroxyl group-containing alkyl (meth)acrylates.
Incidentally, the acrylic monomers may be used alone or in combination of two or more. More preferably, the acrylic monomer includes methyl methacrylate among those listed below. In addition, it is preferable to further include structural units derived from alkyl methacrylate (alkyl group having 2 or more carbon atoms) and/or hydroxyalkyl methacrylate. It is even more preferred to contain butyl (meth)acrylate and/or 2-hydroxyethyl (meth)acrylate.

Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and hexyl (meth)acrylate. , cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, methylcyclohexyl (meth)acrylate, bornyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, (meth)acrylic dicyclopentanyl acid, 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 can be mentioned. Among these, it is preferable that the alkyl group has 2 to 8 carbon atoms, and butyl (meth)acrylate is more preferable from the viewpoint of easily obtaining good adhesion to the substrate.

Acrylic monomers may contain hydroxyl group-containing alkyl (meth)acrylates, 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, etc. (Meth)acrylic acid hydroxyalkyl ester, glycol mono(meth)acrylate such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, caprolactone modification (Meth)acrylate, hydroxyethyl acrylamide, and the like. Among these, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred.

<Cyclic ketone 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 preferable.
Five-membered ring cyclic ketone solvents include, for example, cyclopentanone, 2-methyl-2-cyclopenten-1-one, 2-methylcyclopentanone, 3-methylcyclopentanone, 2-ethylcyclopentanone, 3 -ethylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone and the like.
Six-membered cyclic ketone solvents include, for example, cyclohexanone, isophorone, 2-cyclohexen-1-one, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, and 2,6-dimethylcyclohexanone. , 2,2-dimethylcyclohexanone and the like.
Examples of the seven-membered cyclic ketone solvent include cycloheptanone and 2-cycloheptan-1-one.
The content of the cyclic ketone-based organic solvent (A) is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, more preferably 40 to 60% by mass, based on the total mass of the organic solvent. More preferred. This is because the solubility in the resin is improved.
The boiling point of the cyclic ketone organic solvent (A) is preferably 120 to 250°C, more preferably 130 to 230°C.

<Organic Solvent (B) Having a Boiling Point of 120 to 250° C.>
In one embodiment, the screen printing ink preferably contains an organic solvent (B) having a boiling point of 120-250°C. Specifically, it contains at least one selected from the group consisting of glycol ether organic solvents, ester organic solvents, aliphatic organic solvents, aromatic organic solvents, and alcohol organic solvents (organic solvent (B ) does not contain the 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 organic solvent constituting the liquid medium of the screen printing ink. This is because the solubility in the resin is improved.

Glycol ether-based organic solvents 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, and 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 can be mentioned.

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. tart, diethylene glycol monobutyl ether acetate, propylene carbonate and the like.

Examples of aliphatic organic solvents include normal paraffin solvents, isoparaffin solvents, and cycloparaffin solvents.

Examples of aromatic organic solvents include toluene, xylene, ethylbenzene, naphthalene, tetralin, solvent naphtha, and solvents rich in aromatics such as Swasol (manufactured by Cosmo Oil Co., Ltd., Maruzen Petrochemical Co., Ltd.) and Solvesso (Exxon Mobil Co., Ltd.). (manufactured by Japan Energy), and Cactus Fine (manufactured by Japan Energy Co., Ltd.).

Examples of alcoholic organic solvents include diacetone alcohol, N-amyl alcohol, methylisobutylcarbinol, n-butanol, 3-methoxy-3-methyl-1-butanol, ethylene glycol, propylene glycol, and 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.

Among the above, typical boiling points 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 mixed and used, and may be in any ratio.

<Pigment>
The screen printing ink of the present invention may be used in combination with commonly used organic pigments, inorganic pigments, extender pigments, and the like. Organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethineazo, diketopyrrolopyrrole, and isoindoline pigments. are suitable, but not limited to. C.I. described in the Color Index I pigments can be used accordingly. Examples of inorganic pigments include titanium oxide, carbon black, aluminum paste, mica (mica), bronze powder, chromium vermillion, yellow lead, cadmium yellow, cadmium red, ultramarine blue, Prussian blue, red iron oxide, yellow iron oxide, and iron black. be done. Preferred extender pigments include silica, alumina, talc, calcium carbonate, precipitated barium, and the like. The pigment content is preferably 0.1 to 50% by mass, more preferably 5 to 45% by mass, based on the total screen printing ink.

<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, preferably 0.3 to 4% by mass, relative to the entire screen printing ink. Compounds constituting antifoaming agents include acrylic resins, vinyl ether resins, butadiene resins, silicone resins, fluororesins, and modified resins thereof (but not including the above binder resins). The antifoaming agent is preferably a non-silicone resin, and preferably contains at least one resin selected from acrylic resins, vinyl ether resins and butadiene resins.
Examples of commercially available antifoaming agents include the BYK series (manufactured by BYK-Chemie Japan) and the Floren series (manufactured by Kyoeisha Chemical Co., Ltd.).

<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 entire 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). Examples of commercially available leveling agents include POLYFLOW series (manufactured by Kyoeisha Chemical Co., Ltd.). These may be used alone or in combination of two or more.

<Other additives>
In addition, if necessary, additives such as dispersants, wet penetrants, anti-skinning agents, ultraviolet absorbers, antioxidants, cross-linking agents, preservatives, anti-mold agents, viscosity modifiers, pH modifiers, etc. They can be appropriately blended within a range that does not hinder the object of the invention. Among them, it is preferable to use a dispersant. This is because the jet-black feeling of printed matter is improved. As the dispersant, an acidic dispersant is preferred.

<Production of ink for screen printing>
The screen printing ink of the present invention can be produced by a suitable known dispersing method. For example, it is possible to mix a binder resin, a pigment, an organic solvent and an additive in the required amounts, stir well with a stirrer or the like, and then use a dispersing machine such as a three-roll roll, a paint shaker, an attritor, or a sand mill. .

<Base material>
The substrate used to form the printed matter in the present invention is not particularly limited, and includes inorganic substrates such as glass, polyester substrates such as polyethylene terephthalate, polyethylene, polypropylene, ethylene-vinyl acetate and other polyolefin substrates. , nylon bases such as polyamides, acrylic bases, polyvinyl chloride bases, polycarbonate bases, polyurethane bases, epoxy bases, and other resin bases. A laminate of these may be used. In addition, a deposition substrate obtained by depositing an inorganic compound such as silica, alumina, or aluminum on the substrate can also be used, and the deposition-treated surface may be coated with polyvinyl alcohol or the like. In addition, corona treatment, flame treatment, or stretching treatment may be applied. Among the above, a polyvinyl chloride substrate consisting of only a polyvinyl chloride layer, or a film substrate having a polyvinyl chloride layer, which is a laminate having a polyvinyl chloride layer as the outermost layer, is preferable.

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

<label>
A label, which is one embodiment of the present invention, will be described.
For example, if a film substrate having a polyvinyl chloride layer is used as the above substrate and screen printing is performed on the polyvinyl chloride layer, it can be suitably used as a label. The label (printed matter) may be attached to the article by applying an adhesive agent to the printed matter, or may be held on the article by heat shrinkage without using an adhesive agent like a shrink label. It may be in the form of a body-wrapped label, or it may be in the form of applying an adhesive or heat sealing only to the edges of the printed matter and wrapping it around the article. Either form is preferred.

EXAMPLES Hereinafter, the present invention will be specifically described as examples, but the present invention is not limited to the following examples. In the present invention, unless otherwise specified, "part" represents "mass part" and "%" represents "mass%".

<Measurement of various numerical values>
(acid number)
It was measured according to the method described in JISK0070.
(Molecular weight and molecular weight distribution)
Weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) were measured by GPC (gel permeation chromatography), and were obtained as converted molecular weights using polystyrene as a standard substance.
GPC device: Showa Denko Shodex GPC-104
Column: The following columns were connected in series and used.
Showa Denko Shodex LF-404 2 Showa Denko Shodex LF-G
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 measurement). In addition, DSC8231 manufactured by Rigaku Co., Ltd. is used as the measuring instrument, the measurement temperature range is -70 to 250 ° C., the temperature increase rate is 10 ° C./min, and the midpoint between the endothermic start temperature and the end temperature based on the glass transition in the DSC curve is measured. was taken as the transition temperature.

<Example 1> [Preparation of ink S1 for screen printing]
25 parts of vinyl chloride-vinyl acetate copolymer resin (Solbin C, 0% vinyl alcohol, 87% by mass of vinyl chloride, 13% by mass of vinyl acetate, glass transition temperature of 70°C, manufactured by Nissin Kagaku Kogyo Co., Ltd.) as a binder resin, DIANAL BR-77 (Mitsubishi Chemical Co., Ltd. acrylic resin structural unit derived from methyl methacrylate as a structural unit 20 to 50% by mass, weight average molecular weight 60000, acid value 18 mgKOH / g glass transition temperature 80 ° C.), Mitsubishi Chemical Co.) 5 parts, Cyclic ketone-based organic solvent cyclohexanone (boiling point 155.6 ° C.) as organic solvent 29 parts, aromatic organic solvent Swasol 1000 (component C9 aromatic hydrocarbon, manufactured by Maruzen Petrochemical Co., Ltd. boiling point 167 ° C.) 29 parts, non-silicone defoaming 2 parts of BYK-057 (butadiene copolymer, manufactured by BYK-Chemie Japan) as an agent and 10 parts of pigment (CI Pigment Blue 15:4) are uniformly mixed using a mixer rotary stirrer, and then 3 A screen printing ink (S1) was prepared by making two passes through this roll disperser.

<Examples 2 to 22, Comparative Examples 1 to 6> [Production of screen printing inks S2 to S22 and T1 to T6]
Screen printing inks were prepared in the same manner as in Example 1. Abbreviations in Tables 1 and 2 are shown below. Numerical values in the table represent "parts" unless otherwise specified, and blanks indicate that they are not used.
Dianal BR-87: manufactured by Mitsubishi Chemical Corporation Acrylic resin having a structural unit derived from methyl methacrylate as a structural unit, weight average molecular weight 25000, acid value 10 mgKOH / g, glass transition temperature 105 ° C.
Paraloid B66: manufactured by Dow Chemical Company Acrylic resin having a structural unit derived from methyl methacrylate as a structural unit, weight average molecular weight 70000, acid value 3.5 mgKOH/g, glass transition temperature 50°C
Solbin TA3: Vinyl chloride-acrylic copolymer resin manufactured by Nissin Chemical Co., Ltd. Vinyl chloride unit 83% by mass Glass transition temperature 65 ° C.
Solbin A: Vinyl chloride-vinyl acetate copolymer resin manufactured by Nissin Chemical Co., Ltd. Vinyl chloride unit 92% by mass Vinyl alcohol unit 3% by mass Glass transition temperature 76 ° C.
Solbin TAO: Vinyl chloride-vinyl acetate copolymer resin manufactured by Nissin Chemical Co., Ltd. Vinyl chloride unit 91% by mass, vinyl alcohol unit 7% by mass, glass transition temperature 77°C
Solbin TA5R: Vinyl chloride-vinyl acetate copolymer resin manufactured by Nissin Chemical Co., Ltd. Vinyl chloride unit 88% by mass Vinyl alcohol unit 11% by mass Glass transition temperature 78 ° C.
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 Silicon KF-96-1000CS: Silicone antifoaming agent (manufactured by Shin-Etsu Chemical Co., Ltd.)
Dianal BR-80: Mitsubishi Chemical Corporation acrylic resin weight average molecular weight 100000
Acrylic resin A: acrylic resin having a weight average molecular weight of 8000 and a glass transition temperature of 70°C having structural units derived from methyl methacrylate Isophorone: boiling point of 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
Vylon 200: Amorphous polyester resin manufactured by Toyobo Co., Ltd.

<Printing with screen printing ink S1>
Using a label film (manufactured by Oji Tac Co., Ltd., PVCW80/F93/YW16, 80 μm) having a polyvinyl chloride layer as a base material, the screen printing ink S1 was applied onto this base material by a screen printing plate (NBC Meshtec Co., Ltd.). A screen-printed material was produced by screen-printing a pattern using L-SCREEN, 100-035/255PW).

<Examples 1 to 22, Comparative Examples 1 to 6> [Printing with screen printing inks S1 to S22 and T1 to T6]
Prints were produced in the same manner as in Example 1, except that the screen printing inks listed in Table 2 were used instead of the screen printing ink S1 used in Example 1.

<Evaluation of screen printing ink and its printed matter>
The screen printing inks and printed materials obtained in the above Examples and Comparative Examples were evaluated as follows. Evaluation results are shown in Tables 1 and 2.

<Low temperature aging stability>
The screen printing inks obtained in Examples 1 to 22 and Comparative Examples 1 to 6 were each kept at -5°C for 5 days. The change in viscosity value before and after holding was evaluated. The criteria for evaluation results are as follows.
A (Excellent): Viscosity change of less than 10%.
B (Good): Viscosity change of 10% or more and less than 20%.
C (defective): Viscosity change of 20% or more.
Industrially applicable levels are A and B.

<Evaluation of leveling property>
Evaluation was carried out using the prints obtained in Examples 1-22 and Comparative Examples 1-6. The criteria for evaluation results are as follows. "Printing unevenness" refers to a state in which the color density of the printed layer is uneven.
A (excellent): Printing unevenness in less than 5% of the pattern area.
B (Good): Printing unevenness in an area of 5% or more and less than 20% in the pattern.
C (defective): 20% or more of the area in the pattern has printing unevenness.
Industrially applicable levels are A and B.

<Moisture resistant adhesion>
Evaluation was carried out using the prints obtained in Examples 1-22 and Comparative Examples 1-6. Appearance of the printed surface after exposing the printed matter to an atmosphere of 40°C and 80% humidity for 24 hours, then attaching a 12 mm wide adhesive tape (cellophane tape manufactured by Nichiban Co., Ltd.) to the printed surface and quickly peeling it off. was determined visually. Criteria for evaluation results are as follows.
A (excellent): The ink film on the printed surface was not peeled off at all.
B (Good): The peeling area of the ink film was 5% or more and less than 20%.
C (defective): The peeling area of the ink film is 20% or more.
Industrially applicable levels are A and B.

<Evaluation of metastasis>
Evaluation was performed using the screen printing inks obtained in Examples 1 to 22 and Comparative Examples 1 to 6. In the following evaluations, the transfer rate means the weighted calculated value of the amount of ink transferred per unit area in one printing. The criteria for evaluation results are as follows.
A (excellent): The transfer rate of printing ink is 90% by mass or more.
B (Good): The transfer rate of printing ink is 80% by mass or more and less than 90% by mass.
C (defective): The transfer rate of printing ink is less than 80% by mass.
Industrially applicable levels are A and B.

The present invention has been made to solve the above problems, and has made it possible to provide a screen printing ink and a printed material which are excellent in low-temperature aging stability, leveling property, moisture-resistant adhesion, and reprintability. .
Cyclic ketone-based organic solvent (A) Comparative Example 1 was poor in low-temperature aging stability, leveling property, and transition property. Comparative Example 3, in which the type of binder resin was different, resulted in poor low-temperature aging stability, leveling properties, and moisture-resistant adhesion. Comparative Example 6, in which the weight average molecular weight of the acrylic resin is high, resulted in poor low-temperature aging stability, leveling properties, and transfer properties. Comparative Example 5, in which the acrylic resin had a low weight-average molecular weight, resulted in inferior low-temperature aging stability and moisture-resistant adhesion.

Claims (8)

A screen printing ink containing a binder resin and an organic solvent,
The binder resin contains a vinyl chloride copolymer resin and an acrylic resin (excluding the vinyl chloride copolymer resin),
The acrylic resin comprises an acrylic resin (a) having a weight-average molecular weight of 10,000 to 80,000 and having structural units derived from methyl methacrylate,
A screen printing ink, wherein the organic solvent contains a cyclic ketone-based organic solvent (A). The screen printing ink according to claim 1, containing 25 to 45% by mass of the binder resin based on the total mass of the binder resin and the organic solvent. 3. The screen printing ink according to claim 1, which contains 20 to 80% by mass of the cyclic ketone organic solvent (A) 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. 4. The screen printing ink according to any one of 1 to 3. The screen printing ink according to any one of claims 1 to 4, wherein the vinyl chloride copolymer resin contains 2 to 10% by mass of vinyl alcohol units with respect to the total mass of the vinyl chloride copolymer resin. The screen printing ink according to any one of claims 1 to 5, further comprising an antifoaming agent that is a non-silicone compound. A printed matter having a printing layer formed of the screen printing ink according to any one of claims 1 to 6 on a substrate. 8. The printed matter according to claim 7, wherein the substrate is a film substrate having a polyvinyl chloride layer.