JP5169062B2 - Conductive ink composition - Google Patents

Description

  The present invention relates to a conductive ink for solvent-type printing that can control the surface resistance value of various base materials by coating on various plastic films, plastic sheets, synthetic resin molded articles, or paper. Furthermore, the present invention relates to a conductive ink that can exhibit conductivity by being coated on the surface of a substrate, and can be used for applications such as trays for conveying ICs and electronic components.

  In recent years, OA devices and electronic devices have been reduced in size, weight, integration, and accuracy, and accordingly, there has been an increasing demand for reducing dust and dust adhesion to electrical and electronic parts as much as possible. In other words, these electric and electronic parts cause problems such as poor contact and reading errors when dust and dirt adhere to them. The demands are getting stricter due to accuracy.

  However, since the plastic sheet as the base material is inherently non-conductive, it is easily charged and dust and dust are likely to adhere to it. For this reason, there exists a problem that the dust and dust adhering to the components for conveyance will adhere to an electrical / electronic component main body after conveyance during conveyance. In order to prevent this, plastic sheets used for conveying parts have been worked on by kneading carbon or the like in order to reduce electrical resistance and make it conductive.

  Originally, it should be sufficient to suppress the charging only on the surface of the plastic sheet. However, in the kneading type, carbon is included in the sheet, which may increase the cost. Patent Document 1 describes a method for manufacturing a conductive sheet in which a conductive coating using carbon is applied to a plastic sheet.

  Further, as conductive materials other than carbon, metals, conductive metal oxides, inorganic materials (titanium oxide, barium titanate, mica, etc.) whose surfaces are treated with ATO or ITO are used.

Furthermore, as a non-spherical inorganic filler, Patent Document 2 consists of a synthetic resin paint containing a conductive material having needle-like crystals with a major axis / minor axis ratio of 5-30 in the ratio of major axis to minor axis. A conductive decorative board having a surface resistance value of 10 ⁶ to 10 ⁹ Ω is described. However, although various materials containing titanium oxide as an inorganic filler are described, the conductivity in thin film coating is insufficient, and the dispersibility of the conductive material may not be good. There were cases where problems occurred in film properties and paint stability.

In addition, with the reduction in size, weight, integration, and accuracy, the conductive sheet has been cleaned with water and alcohol to reduce dust and dust, and the alcohol resistance of the ink film has become necessary. .
JP-A-6-000925 JP-A-9-327891

The present invention is an ink capable of making the surface resistance value of a substrate surface printed by a thin film coating printing machine such as a gravure printing system 10 ⁷ Ω / □ or less, and is excellent in printability and printing effect. An object is to provide a conductive ink. It is another object of the present invention to provide a conductive ink composition capable of imparting alcohol resistance by selecting a resin system.

The present invention is a conductive ink composition intended to be applied to a plastic film, a plastic sheet, a synthetic resin molded product, or paper, and is characterized by the following (A) to (C): The present invention relates to an ink composition.
(A) A conductive ink composition in which titanium oxide having a surface covered with antimony-doped tin oxide is dispersed in a thermoplastic resin.
(B) The titanium oxide is a needle-like crystal, the ratio of the major axis to the minor axis of the titanium oxide is major axis / minor axis = 5 to 25, and the major axis is 0.5 to 10 μm. .
(C) The thermoplastic resin is at least one thermoplastic resin selected from polyester urethane, polyester, acrylic resin, and modified polyolefin.

In the present invention , the thermoplastic resin is polyester and / or polyester urethane, the number average molecular weight of the polyester and polyester urethane is 10,000 to 50,000, and the glass transition temperature is 60 ° C to 110 ° C. It is related with the said conductive ink composition characterized .

Furthermore, this invention relates to the said conductive ink composition characterized by containing 100-550 weight part of titanium oxide with respect to 100 weight part of thermoplastic resins .

Furthermore, the present invention relates to a coated product obtained by coating the conductive ink composition on a plastic film, a plastic sheet, a synthetic resin molded product, or paper .

According to the present invention, the surface resistance value of the substrate surface printed by a thin film coating printing machine such as a gravure printing method can be made 10 ⁷ Ω / □ or less, and the conductivity is excellent in printability and printing effect. Ink could be provided. Moreover, the conductive ink which can provide alcohol resistance by selection of the resin system was able to be provided.

  Details of the present invention will be described. The surface of the conductive ink composition of the present invention is covered with antimony-doped tin oxide having a major axis / minor axis ratio of 5 to 25 and a major axis of 0.5 to 10 μm. It is characterized in that the needle-like crystal titanium oxide is used as a conductive component and dispersed in a thermoplastic resin.

  As the conductive component used in the present invention, a conductive material having needle-like crystals can be used, and the same effect can be exhibited regardless of the type as long as it has conductivity. For example, there are metal powder, carbon-based powder, metal oxide and the like. More specifically, examples of the metal powder include copper, nickel, silver, gold, aluminum powder and the like. Examples of the carbon-based powder include graphite and carbon black. Examples of the metal oxide include tin oxide, zinc oxide, indium oxide, antimony oxide, tin oxide, or tin oxide doped or coated with antimony oxide, indium oxide, titanium oxide, potassium titanate, barium sulfate, and the like. . In the present invention, among these conductive materials, rutile-type titanium oxide coated or doped with antimony-containing tin oxide (antimony-doped tin oxide) is used as a conductive component in terms of whiteness, particle strength, and the like. It is characterized by that. In the present invention, the conductive material having the needle crystal can be used in combination with titanium oxide whose surface is covered with antimony-doped tin oxide.

  In the present invention, the needle shape includes not only a so-called rod shape but also a spindle shape, a rice grain shape, a column shape, other similar shapes, and those in which those particles are entangled.

  Further, if the ratio of the major axis to the minor axis (major axis / minor axis) of titanium oxide whose surface is covered with antimony-doped tin oxide is less than 5, the entangled structure of the conductive material crystal is reduced and sufficient. The conductivity cannot be exhibited. On the other hand, when the ratio of the major axis to the minor axis (major axis / minor axis) exceeds 25, the viscosity of the coating liquid increases and the suitability of the coating material decreases, which is not preferable. In addition, if the major axis is less than 0.5 μm, sufficient conductivity cannot be exhibited, and if the major axis exceeds 10 μm, the viscosity of the coating liquid increases and poor dispersion occurs, and the stability of the paint decreases. The physical properties of the coating film are undesirably lowered.

  In the present invention, in addition to the conductive material having titanium oxide whose surface is covered with antimony-doped tin oxide and the needle crystal, other conductive materials can be used in combination. Other conductive materials include, for example, powders such as copper, nickel, silver, gold, and aluminum, metal powders such as fibers, carbon-based powders such as graphite and carbon black, tin oxide, zinc oxide, indium oxide, Examples thereof include antimony oxide, tin oxide, and metal oxides such as tin oxide doped with or coated with antimony oxide, indium oxide, titanium oxide, potassium titanate, and barium sulfate.

  The conductive ink composition of the present invention is characterized in that needle-like crystal titanium oxide whose surface is covered with antimony-doped tin oxide is dispersed in a thermoplastic resin. The thermoplastic resin is used as a binder component of the conductive ink composition of the present invention, and is selected from adhesiveness to various substrates.

  Examples of the thermoplastic resin include polyurethane, polyester urethane, vinyl chloride-vinyl acetate copolymer, modified polyolefin, ethylene-vinyl acetate copolymer, vinyl acetate resin, polyamide, acrylic resin, polyester, alkyd resin, and polyvinyl chloride. Rosin resin, rosin-modified maleic resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, melamine resin, furan resin, epoxy resin, cellulose derivative, polyimide, etc. The above can be mixed and used. Among these, it is possible to use at least one resin selected from polyurethane, polyester urethane, vinyl chloride-vinyl acetate copolymer, polyester, polyamide, cellulose derivative, acrylic resin, and modified polyolefin. It is preferable from the viewpoint of improving the stability.

  Furthermore, in order to bring out the alcohol resistance of the coating film, it is more preferable to use polyester and / or polyester urethane. The number average molecular weight of the polyester and polyester urethane is preferably 10,000 or more, more preferably 10,000 to 50,000. When the number average molecular weight is less than 10,000, sufficient alcohol resistance may not be exhibited, and when the number average molecular weight exceeds 50,000, the viscosity of the ink composition may increase and workability may decrease. The number average molecular weight was measured using GPC (gel permeation chromatography). GPC is liquid chromatography in which a substance dissolved in a solvent (THF; tetrahydrofuran) is separated and quantified by the difference in molecular size, and the number average molecular weight (Mn) is determined in terms of polystyrene.

  Further, the glass transition temperature (Tg) of polyester and polyester urethane is preferably 60 ° C. or higher, more preferably 60 to 110 ° C. If Tg is less than 60 ° C, sufficient physical properties of the coating film may not be obtained, and if it exceeds 110 ° C, the coating film becomes hard and the coating film may be cracked. In addition, the glass transition temperature was measured using DSC (differential thermogravimetric measuring device).

  The ratio of titanium oxide contained in the conductive ink composition of the present invention is preferably 10 to 550 parts by weight with respect to 100 parts by weight of the thermoplastic resin. More preferably, it is 150 to 350 parts by weight. If the content of titanium oxide is less than 100 parts by weight, a desired surface resistivity may not be obtained. On the other hand, if the titanium oxide content exceeds 550 parts by weight, the coating strength may be lowered.

  In the present invention, a dispersant can be used in combination. A polymer dispersant is preferably used as the dispersant. Specific examples include Solspers series (manufactured by Lubrizol), Ajisper series (manufactured by Ajinomoto Co., Inc.), BYK series (manufactured by Big Chemie), and EFKA series (manufactured by EFKA). In addition, when a dispersant such as a surfactant type is used, the adsorption to the surface of the conductive component is insufficient compared to the polymer dispersant, and the particles may easily reaggregate. The dispersant is expensive, and since the molecular weight is lower than that of the binder resin, it is desirable to keep the addition amount small. However, too little dispersant causes poor wetting of the conductive component and a decrease in ink stability. The addition amount is preferably 0.05 to 10 parts by weight with respect to 10 parts by weight of the conductive component.

  When the adhesion to the substrate is insufficient, an anchoring agent can be used, and OP varnish can be applied for the purpose of improving the physical properties of the coating film and preventing the pigment from falling off.

  Since it has the functions required as an ink composition, additives such as leveling agents, antifoaming agents, waxes, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, and flame retardants are used as necessary. You can also.

  Also, by mixing hues other than white, such as yellow, red, indigo, ink, red (orange), grass (green), purple, transparent yellow, peony, vermilion, brown, gold, silver, pearl, etc. It can be colored. Although it is common to color with a pigment, dye, etc., it is not limited to these. Care should be taken when coloring with non-conducting materials, as it may cause a decrease in conductivity depending on the amount added.

  The disperser for dispersing the conductive component is not particularly limited. For example, a paint conditioner (manufactured by Red Devil), a ball mill, a sand mill (such as “Dynomill” manufactured by Shinmaru Enterprises), an attritor, a pearl mill (Such as “DCP mill” manufactured by Eirich), coball mill, basket mill, homomixer, homogenizer (such as “Creamix” manufactured by M Technique), wet jet mill (“Genus PY” manufactured by Genus, “Nanomizer manufactured by Nanomizer”) Or the like. In view of cost, processing capability, etc., it is preferable to use a media type dispersing machine. As the media, glass beads, zirconia beads, alumina beads, magnetic beads, stainless beads, etc. can be used.

  As the substrate, various plastic films, plastic sheets, synthetic resin molded products, paper, or the like are used. Also, a plastic sheet that can be molded, for example, HIPS (impact polystyrene), A-PET (amorphous polyethylene terephthalate), PP, polycarbonate, etc. can be used.

  It does not specifically limit as a coating method of the electroconductive ink composition of this invention, Well-known coating methods, such as a reverse coater, a roll coater, a doctor knife coater, and a gravure coater, can be used.

  The present invention will be described in more detail with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. In the examples, “part” represents “part by weight”.

(Production Example 1)
<Adjustment of polyurethane varnish>
A polyester diol having a number average molecular weight (hereinafter referred to as Mn) of 2000 obtained from adipic acid and 3-methyl-1,5-pentanediol in a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas introduction tube (PMPA2000, manufactured by Kuraray Co., Ltd.) 520.8 parts, Mn2000 polypropylene glycol (PPG2000, manufactured by NOF Corporation) 520.8 parts, N-methyldiethanolamine 18.6 parts, isophorone diisocyanate 316 parts, stannous 2-ethylhexylate 0.25 parts and 200 parts of ethyl acetate were added, reacted at 85 ° C. for 3 hours under a nitrogen stream, and 400.0 parts of ethyl acetate was added and cooled to obtain 1976 parts of a solvent solution of a terminal isocyanate prepolymer. Next, 91.3 parts of isophoronediamine, 1.54 parts of di-n-butylamine, 6.2 parts of aminoethylethanolamine, 1200 parts of ethyl acetate and 1120 parts of isopropyl alcohol were mixed with the resulting terminal isocyanate prepolymer 1581. .1 part was gradually added at room temperature and then reacted at 50 ° C. for 1 hour to obtain varnish A having a solid content of 30% and a number average molecular weight of 35,000.

(Production Example 2)
<Preparation of acrylic resin varnish>
Varnish B was obtained by mixing and dissolving 20 parts of acrylic resin [Dianal BR85, manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight 280000, Tg 105 ° C., acid value 0 mg KOH / g] in 40 parts of methyl ethyl ketone and 40 parts of toluene. .

(Production Example 3)
<Preparation of polyester varnish>
30 parts of polyester [Byron 200, manufactured by Toyobo Co., Ltd., number average molecular weight 17000, Tg 67 ° C., OH value 9 mg KOH / g] was mixed and dissolved in 20 parts of ethyl acetate, 20 parts of methyl ethyl ketone, and 30 parts of toluene to obtain varnish C. Obtained.

(Production Example 4)
<Preparation of polyester varnish>
30 parts of polyester [Byron 240, manufactured by Toyobo Co., Ltd., number average molecular weight 15000, Tg 60 ° C., OH value 9 mg KOH / g] was mixed and dissolved in 35 parts of methyl ethyl ketone and 35 parts of toluene to obtain varnish D.

(Production Example 5)
<Preparation of polyester varnish>
Varnish E was obtained by mixing and dissolving 30 parts of polyester [Byron GK640, manufactured by Toyobo Co., Ltd., number average molecular weight 18000, Tg 79 ° C., OH value 5 mgKOH / g] in 70 parts of methyl ethyl ketone.

[Example 1]
Polyester urethane varnish [Byron UR8200, manufactured by Toyobo Co., Ltd., number average molecular weight 25000, Tg 73 ° C., OH value 5 mg KOH / g, NV 30%] 60 parts, antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / Short axis ratio 12.9) 50 parts, 22 parts of toluene and 22 parts of methyl ethyl ketone were charged into a glass bottle and dispersed for 1 hour using a glass shaker with a glass bead as a medium to obtain printing ink 1.

[Example 2]
Polyester urethane varnish [Byron UR8200, manufactured by Toyobo Co., Ltd., number average molecular weight 25000, Tg 73 ° C., OH value 5 mg KOH / g, NV 30%] 60 parts, antimony-doped tin oxide coated titanium oxide (major axis 2.86 μm, major axis / Short axis ratio 13.6) 50 parts, 22 parts of toluene and 22 parts of methyl ethyl ketone were charged into a glass bottle, and dispersed for 1 hour using a glass shaker with a glass bead as a medium to obtain printing ink 2.

[Example 3]
Polyester urethane varnish [Byron UR8200, manufactured by Toyobo Co., Ltd., number average molecular weight 25000, Tg 73 ° C., OH value 5 mg KOH / g, NV 30%] 60 parts, antimony-doped tin oxide coated titanium oxide (major axis 5.15 μm, major axis / Short axis ratio 19.1) 50 parts, 22 parts of toluene, and 22 parts of methyl ethyl ketone were charged into a glass bottle and dispersed for 1 hour using a glass shaker with a glass bead as a medium to obtain printing ink 3.

[ Reference Example 4]
60 parts of varnish A, 50 parts of antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / minor axis ratio 12.9), 30 parts of ethyl acetate, 14 parts of isopropyl alcohol are charged into a glass bottle, and glass beads are used as media. The ink was dispersed for 1 hour using a paint shaker to obtain printing ink 4.

[Example 5]
Varnish B 64.4 parts, antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / minor axis ratio 12.9) 50 parts, toluene 28 parts, methyl ethyl ketone 28 parts in a glass bottle, glass beads as media Was dispersed for 1 hour using a paint shaker to obtain printing ink 5.

[Example 6]
Modified polyolefin varnish [Super Clon 803 MW (Nippon Paper Chemical Co., Ltd.), chlorine content 30%, NV 30%] 60 parts, antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / minor axis ratio 12.9 50 parts and 44 parts of toluene were charged in a glass bottle, and dispersed for 1 hour using a glass shaker with a glass bead as a medium, to obtain printing ink 6.

[Example 7]
Varnish C 60 parts, antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / minor axis ratio 12.9) 50 parts, toluene 22 parts, methyl ethyl ketone 22 parts are charged into a glass bottle and painted with glass beads as media The ink was dispersed for 1 hour using a shaker to obtain printing ink 7.

[Example 8]
Varnish D 60 parts, antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / minor axis ratio 12.9) 50 parts, toluene 22 parts, methyl ethyl ketone 22 parts are charged in a glass bottle, and glass beads are used as media The ink was dispersed for 1 hour using a shaker to obtain printing ink 8.

[Example 9]
Varnish E 60 parts, antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / minor axis ratio 12.9), 44 parts of methyl ethyl ketone were charged into a glass bottle, and glass beads were used as a medium using a paint shaker The ink was dispersed for 1 hour to obtain printing ink 9.

[Example 10]
Polyester urethane varnish [Byron UR8200, manufactured by Toyobo Co., Ltd., number average molecular weight 25000, Tg 73 ° C., OH value 5 mg KOH / g, NV 30%] 55.5 parts, antimony-doped tin oxide coated titanium oxide (long axis 1.68 μm, long Axis / minor axis ratio 12.9) 25 parts, 11 parts of toluene, and 11 parts of methyl ethyl ketone were charged into a glass bottle, and dispersed for 1 hour using a paint shaker with glass beads as a medium, to obtain printing ink 10.

[Example 11]
Polyester urethane varnish [Byron UR8200, manufactured by Toyobo Co., Ltd., number average molecular weight 25000, Tg 73 ° C., OH value 5 mg KOH / g, NV 30%] 30 parts, antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / Short axis ratio 12.9) 49.5 parts, 11 parts of toluene and 11 parts of methyl ethyl ketone were charged into a glass bottle, and dispersed for 1 hour using a paint shaker using glass beads as a medium, to obtain printing ink 11.

[Comparative Example 1]
Polyester urethane varnish [Byron UR8200, manufactured by Toyobo Co., Ltd., number average molecular weight 25000, Tg 73 ° C., OH value 5 mg KOH / g, NV 30%] 60 parts, antimony-doped tin oxide coated titanium oxide (major axis 1.68 μm, major axis / Short axis ratio 4) 50 parts of ink, 22 parts of toluene, and 22 parts of methyl ethyl ketone were charged into a glass bottle, and dispersed for 1 hour using a glass shaker with a glass bead as a medium to obtain printing ink 12.

[Comparative Example 2]
Polyester urethane varnish [Byron UR8200, manufactured by Toyobo Co., Ltd., number average molecular weight 25000, Tg 73 ° C., OH value 5 mg KOH / g, NV 30%] 60 parts, antimony-doped tin oxide coated titanium oxide (spherical, particle size 0.25 μm) 50 Part, toluene 22 parts, and methyl ethyl ketone 22 parts were placed in a glass bottle, and dispersed for 1 hour using a glass shaker with a glass bead as a medium, to obtain printing ink 13.

[Comparative Example 3]
60 parts of varnish A, 50 parts of titanium oxide (Titanics JR-805, manufactured by Teika), 30 parts of ethyl acetate and 14 parts of isopropyl alcohol are charged into a glass bottle, and dispersed and printed using a glass shaker as a medium for 1 hour. Ink 14 was obtained.

  In order to adjust the printing inks 1 to 5 and 7 to 14 to the viscosity at the time of printing, using a mixed solvent consisting of 50 parts of methyl ethyl ketone and 50 parts of toluene, the Zahn Cup No. Dilution printing inks 1 'to 5' and 7 'to 14' were obtained by diluting them so that the viscosity measured in 3 was 16 seconds.

  In order to adjust the printing ink 6 to the viscosity at the time of printing, Zahn Cup No. Dilution printing ink 6 'was obtained by diluting each so that the viscosity measured in 3 was 16 seconds.

  Diluted printing inks 1 ′ to 5 ′ and 7 ′ to 14 ′ are printed on an A-PET film having a thickness of 200 μm using a gravure proofing machine using a corrosive plate having a plate depth of 30 μm, and printed products (1) to (5 ), (7) to (14) were obtained.

  The diluted printing ink 6 'was printed on a PP film having a thickness of 300 µm using a corrosive plate having a plate depth of 30 microns using a gravure proofing machine to obtain a printed matter (6).

<Surface resistance measurement>
The surface resistance value of the obtained printed film was measured with Loresta-GP MCP-T600 manufactured by Mitsubishi Chemical Corporation. Those outside the measuring range were measured with an ACL800 MEGOHMMETER manufactured by ACL.

<Alcohol resistance>
Alcohol resistance of the obtained printed coating film was determined by using a Gakushin type abrasion resistance tester, soaking isopropyl alcohol into the gold width No. 3 and determining the degree of ink removal at a load of 200 g and 300 times. The determination was performed as follows.
○: No ink is removed.
Δ: There is a portion where ink is removed.
X: Use in applications requiring alcohol resistance is not suitable, but there is no practical problem for other applications.

  The evaluation results are shown in Table 1.

  As shown in Table 1, the conductive ink compositions of Examples 1 to 11 showed a lower surface resistance value than Comparative Examples 1 to 3, and were found to be excellent in conductivity. Furthermore, it turned out that Examples 1-3 and 7-11 electroconductive ink composition is excellent also in alcohol resistance.

Claims (4)

A conductive ink composition characterized by the following (A) to (C), which is a conductive ink composition intended to be applied to a plastic film, a plastic sheet, a synthetic resin molded product, or paper .
(A) A conductive ink composition in which titanium oxide having a surface covered with antimony-doped tin oxide is dispersed in a thermoplastic resin.
(B) The titanium oxide is a needle-like crystal, the ratio of the major axis to the minor axis of the titanium oxide is major axis / minor axis = 5 to 25, and the major axis is 0.5 to 10 μm. .
(C) The thermoplastic resin is at least one thermoplastic resin selected from polyester urethane, polyester, acrylic resin, and modified polyolefin. The thermoplastic resin is polyester and / or polyester urethane, wherein the polyester and polyester urethane have a number average molecular weight of 10,000 to 50,000 and a glass transition temperature of 60 ° C to 110 ° C. Item 2. The conductive ink composition according to Item 1. Per 100 parts by weight of the thermoplastic resin, according to claim 1 or 2 conductive ink composition according to characterized in that it contains 100 to 550 parts by weight of titanium oxide. A coated product obtained by coating the conductive ink composition according to any one of claims 1 to 3 on a plastic film, a plastic sheet, a synthetic resin molded product, or paper.