JP2011034708A - Transparent conductive sheet - Google Patents
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本発明は、透明基板上に形成された塗布型の透明導電性シートに関し、その透明導電層の抵抗値の低減と光学的特性とを両立させた透明導電シートに関する。 The present invention relates to a coating-type transparent conductive sheet formed on a transparent substrate, and relates to a transparent conductive sheet that achieves both a reduction in resistance value and optical characteristics of the transparent conductive layer.
従来、透明導電膜や透明導電性インクの材料として、酸化スズ粒子、アンチモン含有酸化スズ粒子、スズ含有酸化インジウム粒子、アルミニウム含有酸化亜鉛、ガリウム含有酸化亜鉛などの導電性酸化微粒子が知られている。中でも、酸化インジウムにスズを含有させたスズ含有酸化インジウム粒子（ＩＴＯ）を含有させたインクは、その可視光に対する高い透光性と、その高い導電性から、静電防止や電磁波遮蔽が要求されるＣＲＴ画面、ＬＣＤ画面などに塗布して使用されている（特許文献１参照）。
しかし、現在、主に用いられている透明導電膜の成膜方法は、真空蒸着法やスパッタリング法などの物理的方法であるため、成膜する基板の大型化に伴って、製造装置が大掛かりとなり、コストが高くなってしまうという問題が生じており、簡便な製造工程である塗布による透明導電膜の成膜がコストの面からも検討されており、特に、スズ含有酸化インジウム粒子を含むインクを塗布して作製された透明導電膜は、タッチパネルなどの、より透光性と導電性を要求される用途への応用が期待されている。
ただ、タッチパネルなどに要求される物理特性は、スパッタＩＴＯ膜をデフォルトとしているため、粒子を用いた塗布型ＩＴＯ膜においては、抵抗値と透過率の両立が難しい。たとえば、特許文献２のように、粒子サイズの異なる粒子を混合することで接触点を増やし、低抵抗化を試みられているが、より低い抵抗値を達成することができていない。
Conventionally, conductive oxide particles such as tin oxide particles, antimony-containing tin oxide particles, tin-containing indium oxide particles, aluminum-containing zinc oxide, and gallium-containing zinc oxide are known as materials for transparent conductive films and transparent conductive inks. . In particular, an ink containing tin-containing indium oxide particles (ITO) in which tin is added to indium oxide is required to have anti-static and electromagnetic shielding because of its high translucency for visible light and high conductivity. Applied to a CRT screen, LCD screen, etc. (see Patent Document 1).
However, currently, the method of forming a transparent conductive film, which is mainly used, is a physical method such as a vacuum evaporation method or a sputtering method, and therefore, as the substrate for film formation becomes larger, the manufacturing apparatus becomes larger. However, there is a problem that the cost becomes high, and the formation of a transparent conductive film by coating, which is a simple manufacturing process, is also being studied from the viewpoint of cost. In particular, an ink containing tin-containing indium oxide particles is used. The transparent conductive film produced by coating is expected to be applied to uses such as a touch panel that require more translucency and conductivity.
However, since the physical properties required for touch panels and the like default to a sputtered ITO film, it is difficult to achieve both resistance value and transmittance in a coated ITO film using particles. For example, as in Patent Document 2, attempts have been made to reduce the resistance by increasing the contact point by mixing particles having different particle sizes, but a lower resistance value cannot be achieved.
本発明は、導電性酸化物微粒子を用いた塗布型の透明導電性シートにおいて、良好な導電性と透明性を兼ね備えた透明導電膜を提供することにある。 An object of the present invention is to provide a transparent conductive film having both good conductivity and transparency in a coating-type transparent conductive sheet using conductive oxide fine particles.
本発明者らは、上記の目的を達成するため鋭意検討した結果、金属の薄膜でコートされた導電性酸化物微粒子と未被覆の導電性酸化物微粒子とを含み、該金属の薄膜でコートされた導電性酸化物微粒子が全導電性酸化物微粒子に２０〜７０％の割合で混合された導電膜形成用塗料を基材に塗布して導電性塗膜を形成した透明導電性シートとすることで、導電塗布膜の抵抗を低下させ、かつ、金属による透明性の低下を極力抑えることができることを見出し、本発明を完成するに至った。 As a result of intensive investigations to achieve the above-mentioned object, the present inventors include conductive oxide fine particles coated with a metal thin film and uncoated conductive oxide fine particles, which are coated with the metal thin film. A transparent conductive sheet in which a conductive coating film is formed by applying a conductive film-forming paint in which conductive oxide fine particles are mixed in a proportion of 20 to 70% to all conductive oxide fine particles to a substrate. Thus, the inventors have found that the resistance of the conductive coating film can be reduced and the reduction in transparency due to metal can be suppressed as much as possible, and the present invention has been completed.
本発明の透明導電シートは、良好な導電性と透明性を兼ね備えているので、電子ペーパー、ＦＰＤ、太陽電池等の透明電極に応用することができる。また、当該透明導電シートの作製方法であれば、プラスチックス、ＰＥＴやポリイミド等のフレキシブルな基板にも適用することができる。 Since the transparent conductive sheet of the present invention has both good conductivity and transparency, it can be applied to transparent electrodes such as electronic paper, FPD, and solar cells. Moreover, if it is a manufacturing method of the said transparent conductive sheet, it can apply also to flexible substrates, such as plastics, PET, and a polyimide.
従来の導電性酸化物粒子のみの塗布膜における導電機構は、粒子同士の物理的接触ならびに周りの有機物による固定によって、成立している。また、抵抗をできるだけ低くするためには、導電性酸化物粒子を極力多く含有させ、接触点を増やすことが必要である。しかし、粒子の含有率が高くなると塗膜の強度（有機物による固定）が著しく低下し、塗膜構造が崩壊しやすくなり、粒子間の接触が絶たれる箇所が生じることで、導電性向上の効果が小さくなる。ある程度の妥協点を見出して含有率が決定されていた。 The conductive mechanism in the conventional coating film of only conductive oxide particles is established by physical contact between the particles and fixation by surrounding organic substances. Moreover, in order to make resistance as low as possible, it is necessary to contain as much conductive oxide particles as possible and increase the number of contact points. However, as the particle content increases, the strength of the coating film (fixation by organic substances) is significantly reduced, the coating film structure tends to collapse, and the contact between the particles is cut off, resulting in an improvement in conductivity. Becomes smaller. The content rate was determined by finding a certain degree of compromise.
また、光学的特性においても、導電性粒子を多く含有させることで、導電性粒子そのものによる透過光の遮蔽のみならず、バインダ成分の減少により表面に直接導電性粒子が現れることにより表面平滑性が低下し散乱光が増え、透明性が低下する。その点においても、ある程度の妥協点を見出して含有率が決定する必要があった。
これに対して、本発明の透明導電性シートのように、導電性の高い金属でコートされた導電性酸化物粒子を塗膜層中にある特定の割合で混合することより、金属接触による化学的結合による通電網が形勢されることで、適度な導電性粒子の含有率で塗膜の導電率を下げることが可能であり、また、塗膜強度および透明性が低下することもない。
In addition, in terms of optical characteristics, the inclusion of a large amount of conductive particles not only shields the transmitted light by the conductive particles themselves, but also the surface smoothness is achieved by the appearance of the conductive particles directly on the surface due to the reduction of the binder component. Decreased and scattered light increases, and transparency decreases. In this respect as well, it was necessary to find a certain degree of compromise and determine the content rate.
In contrast to this, the conductive oxide particles coated with a highly conductive metal, such as the transparent conductive sheet of the present invention, are mixed at a certain ratio in the coating layer, so that the chemical reaction by metal contact is achieved. By forming a current-carrying network by mechanical bonding, the conductivity of the coating film can be lowered with an appropriate content of conductive particles, and the strength and transparency of the coating film are not reduced.
通常、導電性酸化物粒子のみの塗布型透明導電性塗膜は、導電性粒子の含有量が８５ 〜９５ 重量％ 、厚さは、０．５ 〜 ３．０ μ ｍ で構成されており、シートの全光透過率＞８０％、かつ、抵抗値＞１０５Ω/□の透明導電性シートを実現できる。 Usually, the coating-type transparent conductive coating film made of only conductive oxide particles has a conductive particle content of 85 to 95% by weight and a thickness of 0.5 to 3.0 μm. A transparent conductive sheet having a total light transmittance of> 80% and a resistance value of> 10 5 Ω / □ can be realized.
それに対し、本発明の塗布型の透明導電性シートにおいて、これまで不可能と考えられてきた、抵抗値≦１０３Ω/□と透過率＞８０％の両立を実現し、その特性は、スパッタ膜などの透明導電膜の特性に匹敵する。 On the other hand, the coating-type transparent conductive sheet of the present invention achieves both resistance value ≦ 10 3 Ω / □ and transmittance> 80%, which has been considered impossible until now, and its characteristics are sputtered. It is comparable to the characteristics of transparent conductive films such as films.
次に、本発明の透明導電性シートの製造方法について説明する。 Next, the manufacturing method of the transparent conductive sheet of this invention is demonstrated.
本発明の透明導電膜の製造方法は、金属でコートされた導電性酸化物粒子を作製する工程と、上記導電性酸化物粒子と樹脂成分とを含むコーティング組成物を作製する工程と、透明基材の上に、上記コーティング組成物を塗布して塗膜を形成する工程とを含む。図１は、本発明の製造方法により得られる透明導電膜の一例を示す概略断面図である。図１において、透明導電膜１２は、透明基材１１の一方の主面に設けられている。
（金属でコートされた導電性酸化物粒子の作製）
本発明で用いるコアの透明導電性粒子は、透明性と導電性を兼ね備えた粒子であればよく、窒化物インジウム、スズ、亜鉛、カドミウム、インジウムの金属酸化物のいずれか１種類以上を主成分として、スズ、アンチモン、アルミニウム、ガリウムがドープされた導電性酸化物粒子で、たとえば、アンチモン含有酸化スズ粒子（ＡＴＯ）、スズ含有酸化インジウム粒子（ＩＴＯ）、アルミニウム含有酸化亜鉛粒子（ＡＺＯ）、ガリウム含有酸化亜鉛粒子（ＧＺＯ）等が挙げられるが、とくに、ＩＴＯが、透明性、導電性や化学特性に優れていて好ましい。ただ、透明導電性粒子は、透明性と導電性を兼ね備えた粒子であればよい。
The method for producing a transparent conductive film of the present invention includes a step of producing conductive oxide particles coated with a metal, a step of producing a coating composition containing the conductive oxide particles and a resin component, and a transparent group. And applying a coating composition on the material to form a coating film. FIG. 1 is a schematic cross-sectional view showing an example of a transparent conductive film obtained by the production method of the present invention. In FIG. 1, the transparent
(Preparation of conductive oxide particles coated with metal)
The transparent conductive particles of the core used in the present invention may be particles having both transparency and conductivity, and the main component is any one or more of indium nitride, tin, zinc, cadmium, and indium metal oxides. As conductive oxide particles doped with tin, antimony, aluminum, gallium, for example, antimony-containing tin oxide particles (ATO), tin-containing indium oxide particles (ITO), aluminum-containing zinc oxide particles (AZO), gallium Examples thereof include zinc oxide particles (GZO), and ITO is particularly preferable because of its excellent transparency, conductivity, and chemical properties. However, the transparent conductive particles may be particles having both transparency and conductivity.
コア粒子表面にコートする方法としては、ＣＶＤや真空蒸着などの真空系の物理的手法、攪拌エネルギーによるメカノケミカル法、さらには、有機溶媒中で、コア粒子表面に有機金属材料を分解析出させる化学的手法などが考えられる。
大型の設備を必要としないメカノケミカル法の一例としては、ボールミルやヘンシェルタイプの攪拌ミキサーなどによる表面改質法が挙げられ、コアの透明導電性粒子と該当する金属とを密閉容器の中にいれ、高速回転させることで、コア粒子表面が金属コートされた導電性酸化物微粒子が合成できる。
また、コート時、コア粒子ならびに金属粒子が酸化することを防ぐため、チッソ、アルゴン、水素などの不活性ガスにて封入しておくほうが好ましい。もしくは、コート処理後に、水素ガス気流下、１００〜５００℃の加熱還元処理を行っても良い。
As a method for coating the surface of the core particles, a vacuum physical method such as CVD or vacuum deposition, a mechanochemical method using stirring energy, or an organic metal material is decomposed and deposited on the surface of the core particles in an organic solvent. Chemical methods are possible.
An example of a mechanochemical method that does not require large-scale equipment is a surface modification method using a ball mill or a Henschel type stirring mixer. The transparent conductive particles of the core and the corresponding metal are placed in a sealed container. By rotating at high speed, conductive oxide fine particles whose core particle surfaces are metal-coated can be synthesized.
Further, it is preferable to enclose with an inert gas such as nitrogen, argon or hydrogen in order to prevent oxidation of the core particles and metal particles during coating. Or you may perform a 100-500 degreeC heat reduction process under a hydrogen gas stream after a coating process.
用いる金属としては、融点が低く、低エネルギーにより化学的に結合する材料が好ましく、ガリウム、インジウム、スズなどが挙げられる。
コートする重量比としては、コア粒子重量に対し、１〜２０重量％が好ましく、均一コートの観点より、２〜１０重量％がさらに好ましい。１重量％以下の場合は、コア粒子の表面をコートすることができず、また、２０重量％以上の場合は、コア粒子間の結合凝集が激しく、未被覆導電性酸化物粒子と混合させることが困難となる。
As a metal to be used, a material having a low melting point and chemically bonded with low energy is preferable, and examples thereof include gallium, indium, and tin.
The coating weight ratio is preferably 1 to 20% by weight, more preferably 2 to 10% by weight from the viewpoint of uniform coating, based on the core particle weight. When the amount is 1% by weight or less, the surface of the core particle cannot be coated, and when the amount is 20% by weight or more, the bond aggregation between the core particles is severe, and the core particles are mixed with uncoated conductive oxide particles. It becomes difficult.
上記コア粒子の１次粒子径は５〜１５０ｎｍであることが好ましい。一次粒子径が５ｎｍ未満であると、結晶性の良い粒子を得ることが難しく、一方、１５０ｎｍよりも一次粒子径が大きいと、透明性が低下してしまうため、好ましくない。一次粒子径とは、透過型電子顕微鏡（ＴＥＭ）で観測したときに、粒界で区切られた１つ１つの粒子１００個の粒子径を平均した平均粒子径と定義する。
（透明導電性塗膜層用塗料の作製）
通常の透明導電性塗膜層用塗料は、上記透明導電性粒子を、透明導電膜層中の含有量が８０〜９９重量％の範囲になるようにバインダ溶液中に添加して、分散させる。上記含有量が８０重量％より小さい場合には、透明性は良好であるが導電性粒子の充填率が低く、バインダ成分の割合が大きいために導電性粒子が高密度になりにくく、高い導電性を得にくい。また含有量が９９重量％より多い場合には、バインダが少ないため、導電性粒子を均一に分散することが困難になるため好ましくない。したがって上記無機粒子の含有率は、８０〜９９重量％が好ましく、より好ましくは９０〜９８重量％の範囲である。
The primary particle diameter of the core particles is preferably 5 to 150 nm. If the primary particle size is less than 5 nm, it is difficult to obtain particles with good crystallinity, while if the primary particle size is larger than 150 nm, the transparency is lowered, which is not preferable. The primary particle size is defined as an average particle size obtained by averaging the particle sizes of 100 individual particles separated by grain boundaries when observed with a transmission electron microscope (TEM).
(Preparation of paint for transparent conductive coating layer)
In a normal transparent conductive coating layer coating, the transparent conductive particles are added and dispersed in a binder solution so that the content in the transparent conductive layer is in the range of 80 to 99% by weight. When the content is less than 80% by weight, the transparency is good, but the filling rate of the conductive particles is low, and the ratio of the binder component is large, so that the conductive particles are less likely to become high density and have high conductivity. Hard to get. On the other hand, when the content is more than 99% by weight, it is not preferable because the binder is small and it becomes difficult to uniformly disperse the conductive particles. Therefore, the content of the inorganic particles is preferably 80 to 99% by weight, and more preferably 90 to 98% by weight.
本発明の金属コートした導電性酸化物粒子の場合は、全体の導電性酸化物粒子中の割合として２０〜７０％となるように金属コートした導電性酸化物粒子を添加し、通常の透明導電性塗膜層用塗料と同様に均一となるようにバインダ溶液中で混合・分散させる。該割合が２０％よりも小さいと、シート抵抗を１０３Ωとすることが困難になるため好ましくない。また７０％より大きいと、シート抵抗は１０３Ωとすることが可能であるが、透明性が低下し、８０％以上とすることが困難になるため好ましくない。 In the case of the metal-coated conductive oxide particles of the present invention, the metal-coated conductive oxide particles are added so that the proportion in the total conductive oxide particles is 20 to 70%, and the normal transparent conductive In the same manner as the paint for the conductive coating layer, it is mixed and dispersed in the binder solution so as to be uniform. When the ratio is less than 20%, it is difficult to make the sheet resistance 10 3 Ω, which is not preferable. On the other hand, if it is more than 70%, the sheet resistance can be 10 3 Ω, but it is not preferable because the transparency is lowered and it becomes difficult to make it 80% or more.
上記導電性酸化物粒子を分散させるバインダとしては、特に限定されるものではないが、例えば、塩化ビニル樹脂、アクリル樹脂、塩化ビニル− 酢酸ビニル共重合体、塩化ビニル− ビニルアルコール共重合体、塩化ビニル−酢酸ビニル−無水マレイン酸共重合体、塩化ビニル−水酸基含有アルキルアクリレート共重合体、ニトロセルロース、ポリエステル樹脂、ポリウレタン樹脂などがあり、これらの中から、１ 種または２ 種以上が組み合わせて用いられる。とくに、アクリル樹脂は、光学特性と分散性の良好な樹脂として好ましく使用される。ポリウレタン樹脂としては、例えば、ポリエステルポリウレタン、ポリエーテルポリウレタン、ポリエーテルポリエステルポリウレタン、ポリカーボネートポリウレタン、ポリエステルポリカーボネートポリウレタンなどが挙げられる。 The binder for dispersing the conductive oxide particles is not particularly limited. For example, vinyl chloride resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl alcohol copolymer, chloride There are vinyl-vinyl acetate-maleic anhydride copolymer, vinyl chloride-hydroxyl group-containing alkyl acrylate copolymer, nitrocellulose, polyester resin, polyurethane resin, etc. Of these, one or more types are used in combination It is done. In particular, an acrylic resin is preferably used as a resin having good optical properties and dispersibility. Examples of the polyurethane resin include polyester polyurethane, polyether polyurethane, polyether polyester polyurethane, polycarbonate polyurethane, and polyester polycarbonate polyurethane.
また、無機粒子および導電性酸化物粒子の分散性を向上するための分散剤を添加することもできる。このような分散剤としては、従来から公知のものをいずれも使用することができる。 Further, a dispersant for improving the dispersibility of the inorganic particles and the conductive oxide particles can be added. As such a dispersant, any conventionally known dispersant can be used.
さらに、混合・分散させる手段としては、特に限定されるものではないが、たとえば、ボールミル、サンドミル、ジェットミル、超音波分散機、ペンイントジェーカなどが挙げられる。 Further, the mixing / dispersing means is not particularly limited, and examples thereof include a ball mill, a sand mill, a jet mill, an ultrasonic disperser, and a pen-into-jeka.
本発明において、透明導電性塗膜を形成するための透明基板としては、特に限定されるものではなく、従来から使用されている基板あるいは基材をすべて使用できる。具体的には、ポリエチレンテレフタレート、ポリエチレンナフタレートなどのポリエステル類、ポリオレフィン類、セルローストリアセテート、ポリカーボネート、ポリアミド、ポリイミド、ポリアミドイミド、ポリスルフオン、アラミド、芳香族ポリアミドなどからなる、厚さが通常３〜３００μｍのフィルムまたはシートが用いられる。また基板は、特にフレキシブルである必要はなく、ガラス板のような硬質の基板も使用できる。 In the present invention, the transparent substrate for forming the transparent conductive coating film is not particularly limited, and any conventionally used substrate or base material can be used. Specifically, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins, cellulose triacetate, polycarbonate, polyamide, polyimide, polyamideimide, polysulfone, aramid, aromatic polyamide, etc. A film or sheet is used. The substrate need not be particularly flexible, and a hard substrate such as a glass plate can also be used.
なお、これらの基板には、酸化防止剤、難燃剤、耐熱防止剤、紫外線吸収剤、易滑剤、帯電防止剤等の添加剤が添加されていてもよい。さらに、膜の密着性を向上させるために、基板表面に易接着層（ プライマー）を設けたり、またはコロナ処理、プラズマ処理などの公知の表面処理を行っても良い。 These substrates may contain additives such as antioxidants, flame retardants, heat resistance inhibitors, ultraviolet absorbers, lubricants and antistatic agents. Furthermore, in order to improve the adhesion of the film, an easy adhesion layer (primer) may be provided on the substrate surface, or a known surface treatment such as corona treatment or plasma treatment may be performed.
導電性塗膜層用塗料の調製に用いる有機溶剤には、ベンゼン、トルエン、キシレンなどの芳香族系溶剤、アセトン、シクロヘキサノン、メチルエチルケトン、メチルイソブチルケトンなどのケトン系溶剤、酢酸エチル、酢酸ブチルなどの酢酸エステル系溶剤、ジメチルカーボネート、ジエチルカーボネートなどの炭酸エステル系溶剤、エタノール、イソプロパノールなどのアルコ― ル系溶剤のほか、ヘキサン、テトラヒドロフラン、ジメチルホルムアミドなどが挙げられる。 Organic solvents used for the preparation of the paint for the conductive coating layer include aromatic solvents such as benzene, toluene, xylene, ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, etc. Examples include acetate solvents, carbonate solvents such as dimethyl carbonate and diethyl carbonate, alcohol solvents such as ethanol and isopropanol, hexane, tetrahydrofuran and dimethylformamide.
（透明導電性塗膜層の作製）
まず、上記の方法により作製した透明塗膜層用塗料を、基板上に塗布する。塗布方法は、特に限定されるものではないが、例えばダイコーター、バーコーター、アプリケータ、スクリーン塗布、グラビア塗布、マイクログラビア塗布、スライド塗布、カーテン塗布、スプレー塗布などにより塗布される。
(Preparation of transparent conductive coating layer)
First, the transparent coating layer coating material produced by the above method is applied onto a substrate. The coating method is not particularly limited, and for example, it is applied by die coater, bar coater, applicator, screen coating, gravure coating, microgravure coating, slide coating, curtain coating, spray coating or the like.
塗布により形成される透明塗膜層の厚さは、特に限定されるものではないが、なるべく高い透明性を示し、カレンダ処理あるいはプレス処理（ 以下、「プレス処理等」あるいは単に「プレス処理」ともいう） 前の乾燥後の厚さが０.５ 〜 １ ０ μ ｍ になるように設定する。塗膜層の厚さが０.５ μ ｍ 以下では、透明性の面では問題ないが、透明導電性層の導電性粒子が均一に高密度化されにくくなる。塗膜厚さが１ ０ μ ｍ 以上でも特に問題はないが、高い透明性を示すことが難しくなり、また、塗料を多量に使用することとなり、メリットがない。したがって無機粒子を含む下層透明塗膜層は、プレス処理等を施す前の段階において、０.５ 〜 ２ ０ μ ｍ が好ましく、１ 〜 １ ０ μ ｍ がより好ましい。プレス処理等を施した後の下層透明塗膜層の厚さは０.５ 〜 １ ０ μ ｍ が好ましく、１ 〜 ５ μ ｍ がより好ましい。 The thickness of the transparent coating layer formed by coating is not particularly limited, but it shows as high transparency as possible, and it can be called calendar processing or press processing (hereinafter referred to as “press processing” or simply “press processing”). The thickness after the previous drying is set to 0.5 to 10 μm. When the thickness of the coating layer is 0.5 μm or less, there is no problem in terms of transparency, but the conductive particles of the transparent conductive layer are hardly uniformly densified. Even if the coating thickness is 10 μm or more, there is no particular problem, but it becomes difficult to exhibit high transparency, and a large amount of paint is used, which is not advantageous. Therefore, the lower transparent coating film layer containing inorganic particles is preferably 0.5 to 20 μm, more preferably 1 to 10 μm, before the press treatment or the like. The thickness of the lower transparent coating layer after the press treatment or the like is preferably from 0.5 to 10 μm, and more preferably from 1 to 5 μm.
透明塗膜層上に他の保護液役割を持たせた膜を、二層以上の多層膜であっても良い。例えば、屈折率や紫外線透過率、赤外線透過率等において、異なる光学特性を持つ層を何層かに塗り分け、最上層に透明導電性塗膜層を形成しても良い。この場合でも、透明導電性塗膜層のプレス後の総膜厚が０.５ 〜 １ ０ μ ｍ になるように設定することが好ましいが、特に透明性が損なわれなければ、光学特性等の効果を高めるために、１ ０μ ｍ 以上であってもかまわない。
このような塗布により形成される透明導電性塗膜層の厚さは、プレス処理等の効果が現れる範囲とし、かつ高い導電性を得るために、プレス処理前の乾燥後の厚さが０.５〜２０μｍになるように設定する。塗膜の厚さが０.５μｍ 以下でも、プレス処理等の効果は透明導電性塗膜層全体に及び、かつ透明性の面でも問題はないが、高い導電性が得られにくくなる。また塗膜厚さが２０μｍを超えると、塗膜全体にプレス処理等の効果が現われにくく、含有されている導電性酸化物粒子全てが高密度化されにくく、かつ高い透明性が得られにくくなるため好ましくない。したがって導電性酸化物粒子を含む透明導電性塗膜層は、プレス処理等を施す前の段階において、０.５〜２０μｍが好ましく、１〜１０μｍがより好ましい。プレス処理等を施した後の透明導電性塗膜層の厚さは０.５〜６μｍが好ましく、１〜５μｍがより好ましい。
The film having another protective liquid role on the transparent coating layer may be a multilayer film of two or more layers. For example, a layer having different optical characteristics in refractive index, ultraviolet transmittance, infrared transmittance, etc. may be applied to several layers, and a transparent conductive coating layer may be formed as the uppermost layer. Even in this case, it is preferable to set the transparent conductive coating layer so that the total thickness after pressing is 0.5 to 10 μm. In order to enhance the effect, it may be 10 μm or more.
The thickness of the transparent conductive coating layer formed by such coating is in a range where the effect of press treatment or the like appears, and in order to obtain high conductivity, the thickness after drying before the press treatment is 0. It sets so that it may become 5-20 micrometers. Even when the thickness of the coating film is 0.5 μm or less, the effect of the press treatment or the like extends to the entire transparent conductive coating film layer, and there is no problem in terms of transparency, but it is difficult to obtain high conductivity. When the coating thickness exceeds 20 μm, the effect of press treatment or the like hardly appears on the entire coating film, and all of the contained conductive oxide particles are difficult to be densified, and high transparency is difficult to obtain. Therefore, it is not preferable. Therefore, the transparent conductive coating layer containing conductive oxide particles is preferably 0.5 to 20 μm, more preferably 1 to 10 μm, in a stage before being subjected to press treatment or the like. 0.5-6 micrometers is preferable and, as for the thickness of the transparent conductive coating film layer after giving a press process etc., 1-5 micrometers is more preferable.
作製した透明導電性塗膜に対してプレス加工処理やカレンダ処理をすることにより、導電性酸化物粒子が高充填化され、その結果、透明導電性塗膜層中の平均空孔率が減少し、膜の導電性、光学特性が向上する。光学特性においては、特に粒子間空隙による散乱光が減少することにより、光散乱強度を表す値であるヘイズ値が著しく減少し、透明性の高いものとなる。 By applying press processing and calendaring to the transparent conductive coating film produced, the conductive oxide particles are highly filled, resulting in a decrease in the average porosity in the transparent conductive coating layer. The conductivity and optical characteristics of the film are improved. In the optical characteristics, the haze value, which is a value representing the light scattering intensity, is remarkably reduced by reducing the scattered light due to the interparticle voids in particular, and the transparency becomes high.
カレンダ処理する場合、処理速度は１〜３０ｍ／分、熱処理温度は、上記バインダを構成している樹脂のガラス転移温度（Ｔｇ）に対し、Ｔｇ±５０℃の範囲内、加圧条件は面圧力９.８×１０４〜 ９.８×１０６Ｐａ（１〜１００kg／ｃｍ2 ） の範囲内が有効である。また、プレス処理する場合、熱処理温度は、上記バインダを構成している樹脂のガラス転移温度（ Ｔ ｇ ） に対し、Ｔ ｇ ± ５ ０ ℃ の範囲内、加圧条件は面圧力９.８×１０４〜 ９.８×１０６Ｐａ （ １ 〜 １ ０ ０ k g／ c m 2 ） の範囲内が有効である。 When calendering is performed, the processing speed is 1 to 30 m / min, the heat treatment temperature is within the range of Tg ± 50 ° C. with respect to the glass transition temperature (Tg) of the resin constituting the binder, and the pressing condition is the surface pressure. The range of 9.8 × 10 4 to 9.8 × 10 6 Pa (1 to 100 kg / cm 2 ) is effective. When the press treatment is performed, the heat treatment temperature is within the range of T g ± 50 ° C. with respect to the glass transition temperature (T g) of the resin constituting the binder, and the pressing condition is a surface pressure of 9.8 × The range of 10 4 to 9.8 × 10 6 Pa (1 to 100 kg / cm 2 ) is effective.
次に実施例を挙げて本発明をより具体的に詳細に説明する。ただし、本発明はそれらの実施例に限定されるものではない。 Next, an Example is given and this invention is demonstrated more concretely in detail. However, the present invention is not limited to these examples.
［実施例１］
＜金属コート導電性酸化物粒子の調製＞
一次粒子径２５ｎｍの導電性酸化物粒子としてＩＴＯを１０ｇと所定量の一次粒子径３００μｍの金属粒子としてガリウムを１００ｃｃのテフロン(登録商標)瓶にいれ密閉する。そのテフロン（登録商標）瓶を１５０℃の恒温槽に４時間入れた後、ペイントシェーカーにて３０分混合攪拌する。その後、再度、同様の作業を２回繰り返し、導電性酸化物粒子上に金属をコートした。その結果、粒子径３０ｎｍの金属コート導電性酸化物粒子を調整した。
＜導電性塗料の調製＞
所定量の上記金属コート導電性酸化物粒子と元となる未被覆導電性酸化物粒子を合計で２ｇとなるように秤量し、密閉可能なテフロン（登録商標）容器に入れる。その後、エチレングリコール１８ｇを混合し、さらに０．１ｍｍ径のジルコニアビースを１５０ｇ入れて、ペイントコンディショナーにより、分散処理を施して、実施例および比較例の透明導電膜形成用塗料を調製した。
[Example 1]
<Preparation of metal-coated conductive oxide particles>
10 g of ITO as a conductive oxide particle having a primary particle diameter of 25 nm and gallium as a predetermined amount of metal particle having a primary particle diameter of 300 μm are placed in a 100 cc Teflon (registered trademark) bottle and sealed. The Teflon (registered trademark) bottle is placed in a thermostatic bath at 150 ° C. for 4 hours, and then mixed and stirred for 30 minutes by a paint shaker. Thereafter, the same operation was repeated twice again to coat the metal on the conductive oxide particles. As a result, metal-coated conductive oxide particles having a particle diameter of 30 nm were prepared.
<Preparation of conductive paint>
A predetermined amount of the above metal-coated conductive oxide particles and the original uncoated conductive oxide particles are weighed to a total of 2 g and placed in a sealable Teflon (registered trademark) container. Thereafter, 18 g of ethylene glycol was mixed, 150 g of zirconia beads having a diameter of 0.1 mm was added, and dispersion treatment was performed with a paint conditioner to prepare transparent conductive film forming paints of Examples and Comparative Examples.
次に、以下のようにしてコーティング組成物を調製した。 Next, a coating composition was prepared as follows.
＜コーティング組成物＞
紫外線を遮蔽したプラスチック製ビンに、ガリウムをコートとしたＩＴＯ分散体組成物を下記の成分を計り取り・攪拌して、３０ｇのコーティング組成物１を調製した。
（１）ＩＴＯ分散体組成物 ２０．３ｇ
（２）ライトアクリレート１，６−ＨＸ（共栄社化学製） １．０２ｇ
（３）イルガキュア９０７ ０．１０ｇ
（チバスペシャルティケミカルズ社製）
（４）メチルエチルケトン（和光純薬社製） １．５０ｇ
（５）トルエン（和光純薬社製） １．５０ｇ
（６）シクロヘキサノン（和光純薬社製） ５．６３ｇ
コーティング組成物１の不揮発固形成分中のＩＴＯ粒子の重量含有率は８１．０％であり、ＩＴＯの比重を７．１、アクリル樹脂の比重を１．１として計算すると、体積含有率は３９．５％であった。
＜透明導電膜形成および膜特性評価＞
上記の透明導電膜形成用塗料を用いて、５０ｍｍ×５０ｍｍ×青板ガラス上にスピンコートしたところ、良好にベタ膜を形成することができ、６０℃で減圧乾燥後、大気雰囲気中で３０分間２００℃加熱処理を施すことにより、透明導電膜を形成することができた。形成した透明導電膜の膜特性を評価するために、シート抵抗測定、透過率測定、膜厚測定を行なった。その測定結果を表１に示す。
[実施例２〜５]
金属コート導電性酸化物粒子と未被覆導電性粒子の混合割合を変化させた透明導電膜を、実施例１と同様にスピンコートによる成膜を行ない、膜特性の比較を行なった。それらの透明導電膜形成用塗料を用いて、５０ｍｍ×５０ｍｍ×青板ガラス上に、２０００ｒｐｍで10秒間回転する条件で、スピンコートを行ない、６０℃で減圧乾燥後、大気雰囲気中で３０分間２００℃加熱処理を施すことにより、透明導電膜を形成し、透明導電膜の膜特性を評価した。その測定結果を表1に示す。
＜シート抵抗測定＞
抵抗率測定装置ロレスタＡＰ ＭＣＰ−Ｔ４００(三菱化学(株))により、シート抵抗を測定した。
＜透過率測定＞
紫外可視近赤外分光光度計Ｖ−５７０（日本分光(株)）により、透過率を測定した。ガラス基板の透過率を１００％として、ガラス基板上に形成した透明導電膜の透過率を概算し、５５０ｎｍにおける透過率を透過率とする。
<Coating composition>
The following components of the ITO dispersion composition coated with gallium were weighed and stirred in a plastic bottle shielded from ultraviolet rays to prepare 30 g of coating composition 1.
(1) ITO dispersion composition 20.3 g
(2) Light acrylate 1,6-HX (manufactured by Kyoeisha Chemical) 1.02 g
(3) Irgacure 907 0.10g
(Ciba Specialty Chemicals)
(4) Methyl ethyl ketone (Wako Pure Chemical Industries, Ltd.) 1.50 g
(5) Toluene (Wako Pure Chemical Industries, Ltd.) 1.50 g
(6) Cyclohexanone (Wako Pure Chemical Industries, Ltd.) 5.53 g
The weight content of the ITO particles in the non-volatile solid component of the coating composition 1 is 81.0%, the specific volume of ITO is calculated as 7.1, and the specific gravity of the acrylic resin is 1.1. It was 5%.
<Transparent conductive film formation and film characteristic evaluation>
When spin coating was performed on 50 mm × 50 mm × blue plate glass using the above-mentioned transparent conductive film forming paint, a solid film could be formed satisfactorily, dried at 60 ° C. under reduced pressure, and then 200 minutes in an air atmosphere for 30 minutes. A transparent conductive film could be formed by performing a heat treatment at a temperature of ° C. In order to evaluate the film characteristics of the formed transparent conductive film, sheet resistance measurement, transmittance measurement, and film thickness measurement were performed. The measurement results are shown in Table 1.
[Examples 2 to 5]
A transparent conductive film in which the mixing ratio of metal-coated conductive oxide particles and uncoated conductive particles was changed was formed by spin coating in the same manner as in Example 1, and the film characteristics were compared. Using these transparent conductive film forming paints, spin coating was performed on 50 mm × 50 mm × blue plate glass under the condition of rotating at 2000 rpm for 10 seconds, dried under reduced pressure at 60 ° C., and then 200 ° C. for 30 minutes in the air atmosphere. By performing the heat treatment, a transparent conductive film was formed, and the film characteristics of the transparent conductive film were evaluated. The measurement results are shown in Table 1.
<Sheet resistance measurement>
Sheet resistance was measured with a resistivity measuring apparatus Loresta AP MCP-T400 (Mitsubishi Chemical Corporation).
<Transmittance measurement>
The transmittance was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 (JASCO Corporation). Assuming that the transmittance of the glass substrate is 100%, the transmittance of the transparent conductive film formed on the glass substrate is estimated, and the transmittance at 550 nm is defined as the transmittance.
金属コートした導電性酸化物粒子を特定の割合で混合することで、塗布型の透明導電性シートにおいて、良好な導電性と透明性を兼ね備えた透明導電膜を提供することができ、タッチパネルや電子ペーパーなどのフレキシブルデバイスの性能向上を図ることができる。 By mixing conductive oxide particles coated with metal at a specific ratio, a transparent conductive film having good conductivity and transparency can be provided in a coating-type transparent conductive sheet. The performance of flexible devices such as paper can be improved.
１１ 透明基材
１２ 透明導電膜
11
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| WO2015053160A1 (en) * | 2013-10-08 | 2015-04-16 | 東洋紡株式会社 | Conductive paste, conductive thin film, and circuit |
| JP2019516208A (en) * | 2016-02-29 | 2019-06-13 | リキッド ワイヤ エルエルシーＬｉｑｕｉｄ Ｗｉｒｅ Ｌｌｃ | Liquid wire |
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| JP7141042B2 (en) | 2016-02-29 | 2022-09-22 | リキッド ワイヤ エルエルシー | liquid wire |
| US11585705B2 (en) | 2016-02-29 | 2023-02-21 | Liquid Wire Inc. | Sensors with deformable conductors and selective deformation |
| US11955253B2 (en) | 2016-02-29 | 2024-04-09 | Liquid Wire Inc. | Deformable conductors and related sensors, antennas and multiplexed systems |
| DE112021003838T5 (en) | 2020-08-25 | 2023-05-04 | Wacom Co., Ltd. | COVER FILM FOR PIN SENSOR AND PIN SENSOR |
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