JP6376503B1 - Printing ink and printed matter - Google Patents

Abstract

The present invention provides a printing ink and a printed matter that have excellent stability over time, leveling properties, and transferability, and can achieve both blackness and transparency with high blackness. A printing ink comprising carbon nanotubes having an average diameter of 5 to 30 nm and a binder resin, wherein the binder resin comprises an acrylic resin having an acid value of 1 to 25 mg KOH / g, and thixo at 25 ° C. A printing ink having an index of 1.1 to 1.9 and a printed matter printed on the substrate with the printing ink. [Selection figure] None

Description

The present invention relates to a printing ink and a printed matter printed using the same.

Various printing inks such as gravure printing inks, flexographic printing inks, screen printing inks, offset inks are known as printing inks. Among them, black inks (sometimes called black inks / black inks) ) Mainly uses carbon black as a colorant, and depending on the characteristics of the carbon black, the hue and the printability of the printing ink are greatly affected. For carbon black, it is necessary to select carbon black according to the required properties, but it is difficult to maintain good dispersion stability compared to other organic pigments, and printing density is insufficient when trying to satisfy printability In many cases, it is difficult to satisfy desired characteristics such as insufficient ink film characteristics when the printing density is increased (Patent Document 1).

Prints printed with black ink using carbon black can produce black prints with high hiding power due to the strong coloring power of carbon black, but in recent years the market for prints that are black but easy to transmit light There is an increasing demand. However, depending on the carbon black content in the ink, when trying to obtain such a printed matter, increasing the carbon black content makes it difficult to transmit light, although the desired blackness is obtained. When the rate is lowered, there is a problem that the blackness is lowered although it is easy to transmit light, and it has been difficult to obtain a printed matter capable of achieving both blackness and transparency.

Japanese Patent Laying-Open No. 2015-101688

  The problem to be solved by the present invention has been made to solve the above-mentioned problems, and is excellent in stability over time, leveling and transferability, and can achieve both blackness and transparency with high blackness. To provide ink and printed matter.

As a result of intensive studies, the present inventors have found that the above problems can be solved, and have completed the present invention. That is, the present invention is a screen printing ink comprising carbon nanotubes having an average diameter of 5 to 30 nm, a binder resin, and an organic solvent , wherein the acid value is 1 to 25 mgKOH / g in the total mass of the binder resin. A screen printing ink having a glass transition temperature of 60 to 110 ° C., an acrylic resin having a structural unit composed of methyl methacrylate of 70 to 100% by mass , and a thixo index at 25 ° C. of 1.1 to 1.9 About.

The present invention also relates to the above screen printing ink , wherein the acrylic resin has a weight average molecular weight of 20,000 to 100,000 .
Moreover, this invention relates to the said ink for screen printings in which the said organic solvent contains the organic solvent whose boiling point is 50-250 degreeC.

Moreover, this invention relates to the said ink for screen printing which further contains 0.1-2 mass% of antifoamers.

The present invention also relates to the above screen printing ink, wherein the antifoaming agent is non-silicone.

Moreover, this invention relates to the said ink for screen printing whose viscosity in 25 degreeC is 2-20 Pa.s.

The present invention also relates to the above printing screen ink for screen printing.

Moreover, this invention relates to the printed matter which has a printing layer printed on the base material with the said screen printing ink.

  Moreover, this invention relates to the said printed matter whose said base material is a transparent base material.

Moreover, this invention relates to the said printed matter whose L ^* is 10 or less, a ^* is 0-3, and b ^* is 0-7 measured from the surface on the opposite side to the surface which has a printing layer.
(However, L ^* , a ^* and b ^* represent numerical values in the L ^* a ^* b ^* color system defined by JIS Z8729.)

  Moreover, this invention relates to the said printed matter whose average transmittance | permeability in wavelength 380-780nm is 5% or more measured from the surface on the opposite side to the surface which has a printing layer.

  According to the present invention, it has become possible to provide a printing ink and a printed matter that have excellent stability over time, leveling properties, and transferability, and can achieve both blackness and transparency with high blackness.

Hereinafter, the present invention will be described in detail. The printing ink may be simply abbreviated as “printing ink” or “ink”, but it is synonymous. Further, a film formed by printing ink for printing may be referred to as “printing layer”, “ink coating” or “ink layer”, but it is synonymous.

  The printing ink of the present invention is a printing ink comprising carbon nanotubes having an average diameter of 5 to 30 nm and a binder resin, wherein the binder resin contains an acrylic resin having an acid value of 1 to 25 mgKOH / g. Is a printing ink. A carbon nanotube can be favorably disperse | distributed because binder resin contains the acrylic resin which has the said acid value.

The printing ink of the present invention preferably has a viscosity of 2 to 20 Pa · s at 25 ° C. The thixo index (TI) of the printing ink has a TI at 25 ° C. of 1.1 to 1.9, preferably 1.4 to 1.7. TI is an index of thixotropy of the ink, and is expressed by the following formula 1 as a ratio of the viscosities of two points having different ink shear rates (rotational speeds). As a measuring method, a rotary viscometer can be used most simply, and can be obtained regardless of the type of measuring machine. The viscosity means a value measured at 25 ° C. according to JISZ8803.

(Formula 1) Thixo Index (TI) = Xa / Xb

(In the formula, Xa refers to the viscosity at a low rotational speed in the rotary viscometer, and Xb refers to the viscosity at a rotational speed higher than Xa in the rotational viscometer.)

(carbon nanotube)

The carbon nanotube used in the present invention is a carbon nanotube having an average diameter of 5 to 30 nm. Here, the average diameter means an average diameter of a portion corresponding to a circle in the cylindrical shape, and means an average value of diameters of arbitrary 10 carbon nanotubes observed by a scanning transmission electron microscope. By using such carbon nanotubes, the jet blackness of the ink film and the transparency of the printed layer are improved. Moreover, it is estimated that by using an acrylic resin having an acid value of 1 to 25 mgKOH / g, the carbon nanotubes are well dispersed in the printing ink and the state close to the nanodispersion is maintained.

A carbon nanotube is a cylindrical compound in which a six-membered ring network structure (graphite layer) made of carbon is formed into a single-layer or multilayer coaxial tube. A single layer of the graphite layer is called a single-walled carbon nanotube (SWCNT), and a layer of two or more layers is called a multi-walled carbon nanotube (MWCNT). For the carbon nanotubes used in the present invention, either single-walled carbon nanotubes or multi-walled carbon nanotubes may be selected and used in combination for the purpose of adjusting the coloring effect and jet blackness. Among them, it is preferable to contain MWCNT.

The carbon nanotube is preferably contained in the total mass of the printing ink in an amount of 1 to 7% by mass, and more preferably 2 to 5% by mass. By setting it as the said content rate, the printed matter which shows more favorable jetness is obtained. Moreover, it is preferable to contain at 20-40 mass% in the total mass of printing ink solid content. The solid content means the total mass of nonvolatile components in the printing ink.

(Binder resin)
In the present specification, the binder resin refers to a resin that can function as a binder in printing ink, and is preferably a thermoplastic resin. Further, the binder resin contains an acrylic resin having an acid value of 1 to 25 mgKOH / g. The binder resin is preferably contained in an amount of 20 to 40% by mass, and preferably 25 to 35% by mass, based on the total mass of the ink. Moreover, it is preferable that 70-100 mass% of acrylic resins with an acid value of 1-25 mgKOH / g are contained in the total mass of binder resin.

As binder resins other than acrylic resins having an acid value of 1 to 25 mg KOH / g, styrene resins, polyurethane resins, polyepoxy resins, polyester resins, rosin resins, styrene-acrylic resins, styrene-maleic acid resins, acrylic-urethane resins , Dammar resin, vinyl chloride-vinyl acetate copolymer resin, polycarbonate resin, rosin-modified maleic acid resin, rosin ester resin, terpene resin, acrylic resin other than acid value of 1 to 25 mgKOH / g, and other thermoplastic resins. These binder resins may be used in combination as long as the effects of the present invention are not impaired, and it is preferable to use less than 30% in the total mass of the binder resin.

(Acrylic resin having an acid value of 1 to 25 mgKOH / g)
In this specification, the “acrylic resin” refers to a resin having an acrylic monomer as a main component in a structural unit. “Acrylic monomer” means a monomer having an acrylic group or a methacryloyl group, and “methacryl and acryl” may be abbreviated as “(meth) acryl”. In addition, “methacrylate and acrylate” may be collectively referred to as “(meth) acrylate”.

The acrylic resin having an acid value of 1 to 25 mgKOH / g preferably has an acid value of 10 to 25 mgKOH / g, and preferably 10 to 20 mgKOH / g, from the viewpoint of jet blackness of the ink film and improvement of the stability of the printing ink over time. It is more preferable. A method for imparting an acid value to the acrylic resin can be easily obtained by copolymerizing an acidic monomer such as a carboxyl group-containing acrylic monomer and another monomer, but is not limited thereto. Acidic monomers include (meth) acrylic acid, maleic acid, maleic anhydride, phthalic acid, phthalic anhydride, monohydroxyethyl (meth) acrylate succinate, monohydroxyethyl (meth) acrylate phthalate, and hexahydrophthalic acid mono Hydroxyethyl (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, and the like are preferable, and (meth) acrylic acid is particularly preferable. In addition, an acid value means the measured value in JISK0070 (1992).

  The glass transition temperature of the acrylic resin having an acid value of 1 to 25 mg KOH / g (hereinafter sometimes referred to as “Tg”) is preferably in the range of 50 to 110 ° C., and preferably 60 to 110 ° C. More preferably, it is 70 to 100 degreeC. This is because the blocking resistance of the printing layer made of printing ink is improved. The glass transition temperature is a value measured by a differential scanning calorimeter (DSC).

The weight average molecular weight (Mw) of the acrylic resin having an acid value of 1 to 25 mgKOH / g is preferably 20,000 to 100,000, and more preferably 50,000 to 80,000. This is because the properties of the ink coating are improved. In addition, a weight average molecular weight or a number average molecular weight means the conversion value with respect to polystyrene by the gel permeation chromatography (GPC) measurement which used tetrahydrofuran as a solvent.

The acrylic resin contains an acrylic monomer as a structural unit. Below, although the acrylic monomer which comprises an acrylic resin is listed, it is not limited to these. In addition, an acrylic monomer may be used independently and may use 2 or more types together. Among the acrylic monomers listed below, the acrylic monomer preferably contains alkyl methacrylate and / or alkyl acrylate, and more preferably contains methyl methacrylate. The content is preferably 5 to 95% by mass in the total mass of the acrylic resin. The acrylic monomer can also contain a hydroxyl group-containing alkyl (meth) acrylate.

In addition, it is preferable to have 80-100 mass% of at least 1 type of structural unit chosen from the group which consists of methyl methacrylate, alkyl (meth) acrylate, and (meth) acrylic acid in acrylic resin total mass.

  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. , (Meth) acrylic acid cyclohexyl, (meth) acrylic acid cyclopentyl, (meth) acrylic acid methyl cyclohexyl, (meth) acrylic acid bornyl, (meth) acrylic acid isobornyl, (meth) acrylic acid dicyclopentenyl, (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. Among these, it is preferable that carbon number of an alkyl group is 1-6, and (meth) acrylic acid methyl is more preferable from the point that it is easy to obtain favorable adhesiveness with respect to a base material.

  The acrylic monomer may contain a hydroxyl group-containing alkyl (meth) acrylate, such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (Meth) acrylic acid 2-hydroxybutyl, (meth) acrylic acid 3-hydroxybutyl, (meth) acrylic acid 4-hydroxybutyl, (meth) acrylic acid 6-hydroxyhexyl, (meth) acrylic acid 8-hydroxyoctyl, etc. (Meth) acrylic acid hydroxyalkyl ester, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycol mono (meth) acrylate such as 1,4-cyclohexanedimethanol mono (meth) acrylate, cap Lactone-modified (meth) acrylate, and hydroxyethyl acrylamide. Among these, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable.

(Pigment)
The printing ink of the present invention may be used in combination with organic pigments, inorganic pigments and extender pigments that are usually used in addition to the carbon nanotubes. Organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethine azo, diketopyrrolopyrrole, isoindoline, etc. However, the pigment is not limited to these. C. described in the color index. I pigments can be used as appropriate. Examples of the inorganic pigments include carbon black, aluminum paste, mica (mica), bronze powder, chrome vermillion, chrome lead, cadmium yellow, cadmium red, ultramarine blue, bitumen, bengara, yellow iron oxide, and iron black. As extender pigments, silica, alumina, talc, calcium carbonate, precipitated barium, and the like are preferably used.

(Organic solvent)
The printing ink of the present invention preferably contains an organic solvent. As an organic solvent, it is preferable that a boiling point is 50-250 degreeC, and it is more preferable that it is 100 to 220 degreeC. Examples of the organic solvent include glycol ether organic solvents, ester organic solvents, ketone organic solvents, aliphatic organic solvents, aromatic organic solvents, alcohol organic solvents, and ether organic solvents. Two or more of these may be used in combination.

Examples of glycol ether 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, diethylene glycol monomethyl ether. 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.

Examples of ester 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. Examples thereof include tart, diethylene glycol monobutyl ether acetate, and propylene carbonate.

Examples of ketone organic solvents include acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, dipropyl ketone, diisobutyl ketone, methyl amyl ketone, acetonyl acetone, isophorone, cyclohexanone, and methylcyclohexanone. Can be mentioned.

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

  Examples of the aromatic organic solvent include toluene, xylene, ethylbenzene, naphthalene, tetralin, and solvent naphtha, as well as swazol (manufactured by Cosmo Oil Co., Ltd., Maruzen Petrochemical Co., Ltd.) Solvesso (ExxonMobil Corp.) And Cactus Fine (manufactured by Japan Energy).

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, 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.

  Examples of the ether organic solvent include cyclic ethers such as tetrahydrofuran and 1,3-dioxolane. Other liquid media include dimethyl carbonate, ethyl methyl carbonate, and di-n-butyl carbonate.

(Defoamer)
The printing ink of the present invention preferably contains an antifoaming agent. As content, it is preferable that 0.1-2 mass% is contained in the printing ink total mass. Examples of the compound constituting the antifoaming agent include acrylic resins, vinyl ether resins, butadiene resins, silicone resins, fluorine resins, and modified resins thereof (however, the binder resin is not included). The antifoaming agent is preferably a non-silicone resin, and preferably contains at least one resin selected from an acrylic resin, a vinyl ether resin, and a butadiene resin.
For example, as such an antifoamer marketed, BYK series (BIC Chemie Japan Co., Ltd.) Florene series (Kyoeisha Chemical Co., Ltd.) and the like can be mentioned.

(Leveling agent)
The printing ink of the present invention preferably further contains a leveling agent. The content is preferably 0.1 to 1% by mass in the total mass of the printing ink. The compound constituting the leveling agent is preferably an acrylic resin and / or a silicone resin (however, the binder resin is not included). Examples of such leveling agents that are commercially available include the Polyflow series (manufactured by Kyoeisha Chemical Co., Ltd.). These may be used alone or in combination of two or more.

(Other additives)
If necessary, add additives such as dispersants, wetting and penetrating agents, anti-skinning agents, UV absorbers, antioxidants, crosslinking agents, preservatives, fungicides, viscosity modifiers, pH adjusters, etc. It can mix | blend suitably in the range which does not inhibit the objective of invention. Among these, it is preferable to use a dispersant. This is to improve the jet blackness of the printed material. As the dispersant, an acidic dispersant is preferable.

(Manufacture of printing ink)
The printing ink of the present invention can be appropriately prepared by a known dispersion method. For example, the binder resin, carbon nanotubes, organic solvent and additives can be mixed in the required amount and stirred well with a stirrer, etc., and then manufactured with a disperser such as a three-roll, paint shaker, attritor or sand mill. is there.

(Base material)
The substrate used for forming the printed material in the present invention is not particularly limited, and is an inorganic substrate such as glass, a polyester substrate such as polyethylene terephthalate, polyethylene, polypropylene, ethylene-vinyl acetate and other polyolefin substrates. And resin base materials such as nylon base materials such as polyamide, acrylic base materials, polyvinylidene chloride base materials, polycarbonate base materials, polyurethane base materials, and epoxy base materials. Further, a vapor deposition base material in which an inorganic compound such as silica, alumina, or aluminum is vapor-deposited on the base material can be used, and the vapor deposition treatment surface may be coated with polyvinyl alcohol or the like. Further, corona treatment, frame treatment, and stretching treatment may be performed. Among these, a transparent substrate is preferable.

(Printed matter)
The printed material of the present invention refers to a material in which a printing layer made of printing ink is formed on a substrate by an arbitrary printing method. Examples of the printing method include screen printing, offset printing, gravure printing, flexographic printing, etc. Among them, printing by screen printing is preferable.
The printed material has an L ^* value of 10 or less, an a ^* value of 0 to 3 and a b ^* value of 0 to 7 as measured from the surface opposite to the surface having the printed layer printed on the substrate. Is preferred. L ^* , a ^*, and b ^* represent numerical values measured by JISZ8729. In L ^* a ^* b ^* , L ^* represents the lightness of the color as a diffused color in the black direction when the value is 0 and in the white direction when the value is 100. a ^* b ^* represents chromaticity, and a ^* is a hue between red and green. When the value is negative, the hue is in the green direction, and the positive value is the hue in the red direction. b ^* is a hue between yellow and blue, a negative value represents a hue in the blue direction, and a positive value represents a hue in the yellow direction. Note that L ^* a ^* b ^* is expressed as three-dimensional coordinates. The L ^* a ^* b ^* value is a value measured by reflection.
Further, the transmittance is a transmission spectrum measurement in the wavelength range of 300 to 1500 nm from the surface opposite to the surface having the printed layer in the printed matter, and a weighted average value of each transmittance in the visible light wavelength range of 380 nm to 780 nm. It is a value calculated by obtaining and means a measured value in a transmission spectrum. The weighted average value is a value calculated according to JIS R3106 (1998).

  EXAMPLES Hereinafter, although this invention is demonstrated concretely as an Example, this invention is not limited at all by the following Examples. In the present invention, unless otherwise specified, “part” represents “part by mass” and “%” represents “% by mass”, respectively.

(Average diameter of carbon nanotube)
In an observation photograph using a scanning transmission electron microscope (HD-2700, manufactured by Hitachi High-Technologies Corporation), select any 10 carbon nanotubes, measure the diameter of each, and determine the average value to obtain the average diameter of the carbon nanotubes. did.

(Weight average molecular weight)
The weight average molecular weight was determined by GPC (gel permeation chromatography) method. The molecular weight distribution was measured using “ShodexGPCSystem-21” manufactured by Showa Denko KK, and the molecular weight in terms of polystyrene was determined. The measurement conditions are shown below.
Column: The following multiple columns are connected in series.
Tosoh Co., Ltd., TSKgel SuperAW2500,
Tosoh Co., Ltd., TSKgel SuperAW3000,
Tosoh Corporation, TSKgel SuperAW4000,
TSKgel guardcolumn SuperAWH, manufactured by Tosoh Corporation
Detector: RI (differential refractometer),
Measurement conditions: column temperature 40 ° C.
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min

(Acid value)
The measurement was performed according to the method described in JISK0070 (1992).

(Glass transition temperature (Tg))
The glass transition temperature (Tg) was determined by DSC (differential scanning calorimetry measurement). In addition, a measuring machine uses DSC8231 by Rigaku Co., Ltd., measurement temperature range -50-250 degreeC, temperature increase rate 10 degree-C / min, the inflection point of the baseline change based on the glass transition in a DSC curve glass transition temperature It was.

(Viscosity and thixo index (TI))
It was measured using a single cylindrical rotational viscometer at 25 ° C. according to JISZ8803 (2011). The thixo index was calculated as the ratio of the viscosity at 6 rpm and 60 rpm according to the above (Equation 1).

(L ^* a ^* b ^* value)
It measured according to JISZ8781-4 (2013) from the surface on the opposite side to the surface which has a printed layer of printed matter. In addition, the color difference meter (The product made by NIPPONDENSHOKU, SpectroColorMeterSE2000) was used for the measurement. In addition, a measured value says the measured value by reflection.

(Average transmittance)
Using a UV-visible near-infrared spectrophotometer (manufactured by Hitachi, Ltd., UV-3500), a transmission spectrum is measured in a wavelength range of 300 to 1500 nm from the surface of the printed material opposite to the surface having the printed layer, and visible light region. It calculated by calculating | requiring the weighted average value of each transmittance | permeability of wavelength 380nm -780nm.

(Example 1) [Preparation of printing ink S1]
NC-7000 (manufactured by Nanosil Corporation, average diameter 9.5 nm, MWCNT) 3.5 parts as carbon nanotubes, acrylic resin (Dianal BR-116, methyl methacrylate acrylic resin, weight average) with an acid value of 7 mg KOH / g as binder resin Molecular weight 45,000, glass transition temperature 50 ° C. Acid value 7.0 mg KOH / g manufactured by Mitsubishi Chemical) 27.5 parts, BYK-057 (butadiene copolymer, manufactured by Big Chemie Japan) as a non-silicone antifoaming agent 1 5 parts, polyflow NO. 7 (acrylic resin, Kyoeisha Chemical Co., Ltd.) 0.5 parts, 20 parts of butyl cellosolve and 47 parts of diacetone alcohol as a solvent were mixed uniformly using a mixer rotary stirrer, and then a 3-roll disperser was passed through 2 passes. Thus, a printing ink (S1) was prepared. The viscosity of the printing ink (S1) was 2.4 Pa · s.

(Examples 2 to 12, Comparative Examples 1 to 4) [Preparation of printing inks S2 to S10, T1 to T4]
Printing inks were prepared in the same manner as in Example 1 except that the materials and ratios described in Table 1 were used. Abbreviations in the table are shown below. Moreover, the numerical value in a table | surface represents "part" unless there is particular notice, and the blank represents that it is not using.
In this specification, examples other than Examples 2 to 11 (Inks S2 to S11) and Examples 14 to 23 of printed materials using the same are reference examples.

<Carbon nanotube>
Flotube 9000: carbon nanotube, manufactured by CNano, average diameter of 12.5 nm, MWCNT
SMW210: Carbon nanotube, manufactured by Southwest Nano Technologies, average diameter of 10 nm, MWCNT
<Carbon black>
Mitsubishi carbon MA-100: carbon black, manufactured by Mitsubishi Chemical Corporation, primary particle size 24 nm

<Acrylic resin>
Dianal BR-77: acid value 18.5 mgKOH / g, methyl methacrylate / butyl methacrylate acrylic resin weight average molecular weight 65,000, glass transition temperature 80 ° C., Mitsubishi Chemical Corporation Dianal BR-87: acid value 10.5 mgKOH / G, methyl methacrylate / alkyl methacrylate acrylic resin weight average molecular weight 25,000, glass transition temperature 105 ° C., Mitsubishi Chemical's Dianal MB-2389: acid value 2.3 mg KOH / g, methyl methacrylate acrylic resin weight average molecular weight 30,000, glass transition temperature 90 ° C., Paraloid B66 manufactured by Mitsubishi Chemical Co., Ltd .: acid value 3 mg KOH / g, methyl methacrylate acrylic resin weight average molecular weight 70,000, glass transition temperature 50 ° C., Rohm and Haas Dianal BR-110: acid value 0.0 mgKOH / g, acrylic resin weight average molecular weight 72,000, glass transition temperature 90 ° C.
<Polyester resin>
Byron 200: acid value 2 mgKOH / g, amorphous polyester resin, weight average molecular weight 30,000, glass transition temperature 67 ° C., manufactured by Toyobo Co., Ltd. <leveling agent>
KF-96-1000CS: Silicone resin, manufactured by Shin-Etsu Chemical Co., Ltd.

(Example 13) [Printing with printing ink S1]
Using a transparent substrate made of polycarbonate resin (Panlite PC2151 film thickness 300 μm, manufactured by Teijin Ltd.) as a substrate, the above printing ink S1 is screen-printed on this substrate (manufactured by NBC Meshtec, L-SCREEN). , 140-030 / 355PW) to produce a printed matter.

(Examples 13 to 24, Comparative Examples 5 to 8) [Printing with printing inks S2 to S12, T1 to T4]
Instead of the printing ink S1 used in Example 1, printed materials were respectively prepared by the same method as in Example 1 except that the printing ink described in Table 2 was used.

(Evaluation of printing ink and printed matter)
The following evaluation was performed about the printing ink and printed matter obtained by the said Example and comparative example. The evaluation results are shown in Table 2.

(Stability over time)
The printing inks obtained in Examples 1 to 12 and Comparative Examples 1 to 4 were held at 40 ° C. for 5 days, respectively. Changes in viscosity values before and after holding were 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): Viscosity change is 20% or more.
Industrially available levels are A and B.

(Evaluation of leveling properties)
Evaluation was performed using the printed matter obtained in Examples 13 to 24 and Comparative Examples 5 to 8. The criteria for the evaluation results were as follows. “Print unevenness” refers to a state in which the color density of the print layer is uneven.
A (excellent): An area of less than 5% in the pattern has uneven printing.
B (good): An area of 5% or more and less than 20% in the pattern has uneven printing.
C (defect): An area of 20% or more in the pattern has uneven printing.
Industrially available levels are A and B.

(Evaluation of metastasis)
Evaluation was performed using the printing inks obtained in Examples 1 to 12 and Comparative Examples 1 to 4. In the following evaluation, the transfer rate is a calculated value of the weight of ink transferred per unit area in one printing. The criteria for the evaluation results were as follows.
A (excellent): The transfer rate of the printing ink is 90% by mass or more.
B (good): The transfer rate of the printing ink is 80% by mass or more and less than 90% by mass.
C (defect): The transfer rate of the printing ink is less than 80% by mass.
Industrially available levels are A and B.

(Evaluation of jetness)
Evaluation was performed using the printed matter obtained in Examples 11 to 20 and Comparative Examples 5 to 8. The criteria for the evaluation results were as follows.
A (excellent): L ^* is 8 or less, a ^* is 0 to 3, and b ^* is 0 to 7.
B (good): L ^* is more than 8 and 10 or less, a ^* is 0 to 3, and b ^* is 0 to 7.
C (defect): L ^* is greater than 10, a ^* is 4 or more and less than 0 or greater than 3, or b ^* is a value less than 0 or greater than 7.
Industrially available levels are A and B.

(Evaluation of permeability)
Evaluation was performed using the printed matter obtained in Examples 13 to 24 and Comparative Examples 5 to 8. The criteria for the evaluation results were as follows.
A (excellent): The average transmittance of the printed material is 10% or more.
B (good): The average transmittance of the printed material is 5% or more and less than 10%.
C (defect): The average transmittance of the printed material is less than 5%.
Industrially available levels are A and B.

The present invention has been made to solve the above-mentioned problems, and it has become possible to provide a printing ink and a printed matter that are excellent in jetness, leveling, transferability, and transparency.

Claims (10)

An ink for screen printing comprising carbon nanotubes having an average diameter of 5 to 30 nm, a binder resin, and an organic solvent , wherein the total mass of the binder resin has an acid value of 1 to 25 mgKOH / g , and a glass transition temperature. Screen printing ink which is 60-110 degreeC, contains 70-100 mass% of acrylic resins which have a structural unit which consists of methyl methacrylate, and the thixo index in 25 degreeC is 1.1-1.9 . The screen printing ink according to claim 1, wherein the acrylic resin has a weight average molecular weight of 20,000 to 100,000. The ink for screen printing according to claim 1 or 2, wherein the organic solvent contains an organic solvent having a boiling point of 50 to 250 ° C. Furthermore, the ink for screen printing in any one of Claims 1-3 which contains 0.1-2 mass% of antifoamers. The ink for screen printing according to any one of claims 1 to 4 , wherein the antifoaming agent is non-silicone. The ink for screen printing according to any one of claims 1 to 5 , which has a viscosity at 25 ° C of 2 to 20 Pa · s. The printed matter which has the printing layer printed with the ink for screen printing in any one of Claims 1-6 on the base material.   The printed material according to claim 7, wherein the substrate is a transparent substrate. The printed matter according to claim 7 or 8, wherein L ^* is 10 or less, a ^* is 0 to 3 and b ^* is 0 to 7 as measured from a surface opposite to the surface having the printed layer.
(However, L ^* , a ^* and b ^* represent numerical values in the L ^* a ^* b ^* color system defined by JIS Z8729.)   The printed matter according to any one of claims 7 to 9, wherein an average transmittance at a wavelength of 380 to 780 nm, measured from a surface opposite to the surface having the printed layer, is 5% or more.