JP5324517B2 - Conductive coating composition - Google Patents

Description

  The present invention relates to a conductive coatable composition, and can be used as a substitute for indium-tin oxide (ITO), which has been used in conventional transparent conductive films. The present invention relates to a conductive coating composition.

  In recent years, liquid crystal display devices, electroluminescence displays, solar cells, touch panels, and the like have been widely used. For these, laminates called so-called transparent electrodes are used.

  As what is used for this transparent electrode, a laminate called a so-called transparent conductive film is widely used, but ITO is currently widely used as a material for providing conductivity in this transparent conductive film. .

  More specifically, it is obtained by laminating ITO, which is a conductive component, on a surface of a transparent polymer resin film such as a polyethylene terephthalate (PET) film by a so-called dry coating method such as vacuum deposition.

  However, while the demand for ITO has increased explosively, the production of indium (In) used in ITO is small, so it is a so-called rare metal, so future resource depletion has become a problem. Furthermore, if ITO is to be laminated on a PET film or the like by the method described above, a high temperature is required for film formation to obtain a vapor deposition film, and there are fewer choices of base film to be laminated. For this reason, a problem has been pointed out that since the vacuum vapor deposition apparatus is an expensive apparatus, the vapor deposition film obtained is inevitably expensive.

  Therefore, research and development of substances that can replace ITO are being promoted in various fields, and some of them try to replace ITO by applying a conductive resin.

  For example, in the invention described in Patent Document 1, a polymer solution having conductivity and a conductive coating film using the polymer solution are proposed.

JP 2008-146913 A

  The conductive polymer solution described in Patent Document 1 includes a π-conjugated conductive polymer, a dopant, an amide compound, a polyfunctional acrylic having two or more unsaturated double bonds, and a solvent. And containing. And it is said that it is preferable to use a polyanion as a dopant and N-hydroxyacryl (meth) acrylamide and / or N-alkoxyalkyl (meth) acrylamide as an amide compound, respectively.

  When this invention is examined in more detail, for example, polystyrene sulfonic acid (PSS) is cited as an example of a polyanion used as a dopant. This PSS is a non-crosslinked, linear PSS. . In Patent Document 1, linear PSS is combined with a conductive polymer.

  However, since this linear PSS is conventionally rich in water solubility, a conductive polymer solution obtained by combining this linear PSS with a conductive polymer is exposed to a high temperature and high humidity environment such as water vapor. In such a case, the linear PSS easily melts, and therefore, the effect obtained by combining the linear PSS with the conductive polymer, that is, good conductivity may be lost. (Hereinafter, resistance in a high-temperature and high-humidity environment such as water vapor is referred to as “environment resistance” in this specification.)

  On the other hand, as can be seen from the fact that the conventional ITO conductive film in the environment where the conductive film is used as described above is an environmental problem, the conductive film is an alternative to ITO. If it is intended to be used for, for example, it is obvious that properties such as environmental resistance after coating are also required for the conductive polymer solution as a substitute. The described conductive polymer solution is considered to be unable to sufficiently meet such a demand.

  On the other hand, laminating and forming a conductive circuit of a transparent conductive film by printing has recently been studied, but adjusting the viscosity is an important matter, but in order to adjust the viscosity It is necessary to adjust the solid content concentration. And even if it is going to concentrate this conductive polymer solution trying to use the conductive polymer solution of patent document 1 as a conductive coating ink, it cannot concentrate to a required level, or a solid part is 2%-3%. When the concentration is advanced to the extent that the conductive polymer is gelled, it becomes a gel, that is, it becomes a solid, and as a result, the desired ink cannot be obtained. It was not preferred to use.

  Therefore, the present invention has been made in view of such problems, and the object thereof is excellent in environmental resistance, can be concentrated, and can be substituted for a conductive substance such as ITO. It is providing the conductive coating composition which is these, and a transparent conductive film using the same.

In order to solve the above problems, the invention of claim 1 of the present invention, a conductive polymer, a dopant, a conductive coating composition whose main component, wherein the dopant is a dopant , Crosslinked polystyrenesulfonic acid (crosslinked PSS) fine particles that are crosslinked using a crosslinking agent before being doped into the conductive polymer and have a crosslinking degree of 1% or more,
The conductive polymer is polyethylene dioxythiophene (PEDOT), which is a π-conjugated conductive polymer resin .

The invention according to claim 2 of the present invention is the conductive coating composition according to claim 1 , wherein the conductive coating composition has a water-soluble compound having an amide bond and a water-soluble compound having a hydroxyl group. And a compound selected from the group consisting of water-soluble sulfoxide and water-soluble sulfone.

Invention of Claim 3 of this invention is an electroconductive coating composition of any one of Claim 1 thru | or 2 , Comprising: In this electroconductive coating composition, this electroconductive coating composition In order to improve the film-forming property of the product and the adhesion to the substrate, it contains a water-soluble or water-dispersible binder resin, and / or the conductive coating composition wets the substrate. In order to improve the property, it contains a small amount of a surfactant, and / or for the purpose of improving the wettability of the conductive coating composition to the substrate and the drying property of the coating film. This is characterized by containing a water-soluble solvent.

The invention relating to the conductive film according to claim 4 of the present invention is characterized by using the conductive coating composition according to any one of claims 1 to 3 .

The invention relating to the conductive coating ink according to claim 5 of the present invention is characterized by using the conductive coating composition according to any one of claims 1 to 3 .

  As described above, in the case of the conductive coating composition according to the present invention, for example, crosslinked PSS is used as a non-water-soluble dopant in a π-conjugated conductive polymer such as PEDOT. Therefore, even if a conductive film using such a conductive coating composition as an alternative to ITO is exposed to a high humidity environment, the crosslinked PSS contained in the conductive coating composition is insoluble in water, Performance can be maintained. Furthermore, since the composition can be used only in a simple coating process without using an expensive and complicated vacuum deposition apparatus such as conventional ITO, it is inexpensive if applied to the production of a conductive film. A conductive film can be easily obtained. Furthermore, if it is an electroconductive coating composition which concerns on this invention, it is possible to remove the water which is a solvent by concentrating, Therefore, it is possible easily to replace the water which is a solvent with the organic solvent. That is, by utilizing this property, a conductive coating ink using the conductive coating composition according to the present invention can be obtained.

  Embodiments of the present invention will be described below. The embodiment shown here is merely an example, and is not necessarily limited to this embodiment.

(Embodiment 1)
A conductive coating composition according to the present invention will be described as a first embodiment.
The conductive coating composition according to the present embodiment is mainly composed of a conductive polymer and a dopant, and the dopant is a water-insoluble substance.

This will be described in turn below.
First, a conductive polymer, which generally refers to a polymer that literally conducts electricity. A normal polymer is an insulating material, but a conductive polymer is generally characterized by a structure in which double bonds and single bonds are alternately arranged, that is, a main chain in which π conjugation is developed. A π-conjugated conductive polymer resin is used as the conductive polymer used in this embodiment.

  Further, as this π-conjugated conductive polymer, various types such as polyacetylene, polyparaphenylene, polythiophene, polypyrrole, polyaniline, polyacene and the like can be considered. ). PEDOT is preferred because it is the most stable compound because the polymer itself does not decompose in the atmospheric environment.

  However, in reality, the above-mentioned substance has a conductive path, but since there is no charge transfer body (carrier) that can move freely, the substance itself does not exhibit conductivity.

Therefore, for example, conductivity is first manifested by doping a carrier with a conductive polymer such as an inorganic semiconductor such as silicon.

  This doping is performed by adding an appropriate substance (chemical species) such as an electron acceptor (acceptor) such as iodine or an electron donor (donor) such as alkali metal to the conductive polymer. Is referred to as a dopant. Then, the conductive polymer provided with the dopant generates carriers that move freely inside, and as a result, it is possible to obtain conductivity comparable to that of metal while being a polymer resin.

  In the present embodiment, the conductive polymer is PEDOT as described above, but in order to use this PEDOT most effectively, that is, as one of the optimum dopants for effectively extracting the conductivity, PSS is known.

This linear PSS is generally obtained, for example, as follows.
First, 206 g of sodium styrenesulfonate was dissolved in 1000 ml of ion-exchanged water, and 1.14 g of ammonium peroxodisulfate oxidizer solution previously dissolved in 10 ml of water was added dropwise over 20 minutes while stirring at 80 ° C. And the resulting solution is stirred for 2 hours.

  1000 ml of sulfuric acid diluted to 10% by mass and 10000 ml of ion-exchanged water were added to the obtained solution, ie, a sodium styrenesulfonate-containing solution, and the polystyrenesulfonic acid-containing solution was added using an ultrafiltration method. Remove approximately 10,000 ml solution. Next, 10,000 ml of ion-exchanged water is added to the remaining liquid, and about 10,000 ml of solution is removed using an ultrafiltration method. The above ultrafiltration operation was repeated 3 times.

  Then, about 10,000 ml of ion-exchanged water was added to the obtained filtrate, and about 10,000 ml of solution was removed using an ultrafiltration method. This ultrafiltration operation was repeated three times.

  Water in the obtained solution was removed under reduced pressure to obtain colorless solid polystyrene sulfonic acid.

In addition, the ultrafiltration conditions in the above are as follows.
・ Molecular weight cut off of ultrafiltration membrane: 30K
・ Cross flow type Supply liquid flow rate: 3000ml / min
Membrane partial pressure: 0.12 Pa

  For example, a linear PSS can be obtained in this way.

  However, this linear PSS is water-soluble, and this water-solubility becomes a problem in this embodiment.

  That is, the conductive coating composition according to the present embodiment is assumed as an alternative to ITO in a conductive film that has been conventionally obtained with ITO, for example, as described later. In other words, the conductive film using ITO usually requires environmental resistance and the like, and the conductive coating composition according to the present embodiment is used as an alternative to ITO in such a conductive film. If there is, of course, the conductive film using this is also required to have environmental resistance, and for that purpose, it is strongly desired that the conductive coating composition according to the present embodiment has environmental resistance. .

  However, since this linear PSS is water-soluble as described above, if a conductive coating composition using this linear PSS is used, when this conductive coating composition is exposed to an environment such as water vapor, the conductive coating composition is changed. The constituting linear PSS is eluted in response to moisture, that is, the linear PSS falls off from the conductive coating composition.

  Then, as described above, even if the main component PEDOT is supposed to exhibit conductivity, if PDCOT, ie, a state where no dopant exists, PEDOT cannot exhibit conductivity. That is, a substance that should be a conductive coating composition is very likely to lose its conductivity when exposed to an environment such as water vapor. That is, it can be said that environmental resistance is not provided.

  Therefore, the inventor according to the present invention has found that the PSS is optimally derived from the PSS shape rather than the linear shape of the PSS, so that the PSS is not in a straight chain but in a crosslinked state. It has been found that by using cross-linked PSS as a dopant, a conductive coating composition having suitable environmental resistance can be obtained.

This crosslinked PSS is obtained as follows.
Specifically, the method is similar to the method for obtaining the linear PSS described above, but the polymer used is a linear polystyrene sulfonic acid. In this embodiment, a crosslinked polystyrene sulfonic acid is used. In this case, a crosslinked PSS can be obtained.

Cross-linked polystyrene sulfonic acid is obtained as follows.
First, styrene monomer, divinylbenzene monomer, sodium dodecyl sulfate as a surfactant, and potassium peroxodisulfate as a polymerization initiator are added to water and reacted at 80 ° C. for 2 hours. A polymer dispersed in water is obtained. Next, in order to sulphonate this, water is removed by an evaporator, and a solvent is put in the polymer powder to disperse it. Thereafter, 3.3 molar equivalents of concentrated sulfuric acid and 3 molar equivalents of acetic anhydride are added and reacted at 50 ° C. for 5 hours. The resulting precipitate is further transferred to another container, and water is added to this and dispersed in water. The crosslinked polymer thus obtained is used.

  In this case, water is used as a solvent for dispersing the polymer. However, other than this, for example, a solvent in which crosslinked PSS is sufficiently dispersed and does not react with concentrated sulfuric acid, such as dichloroethane, dichloromethane, or chloroform, can be selected. good. Substances other than the above are also conceivable, but further details are omitted here.

  In the present embodiment, a conductive coating composition is obtained using PEDOT and crosslinked PSS described above as main components.

The specific manufacturing method is as follows.
First, ethylenedioxythiophene (EDOT) which is a precursor monomer of PEDOT, the above-mentioned crosslinked PSS as a dopant, water as a solvent, ferric sulfate and sodium peroxodisulfate as an oxidizing agent are mixed. In addition, hydrochloric acid is added to adjust the pH, and the mixture is reacted at 18 ° C. for 23 hours. The ratio at this time is as follows.
Cross-linked PSS to EDOT 1: 2 molar equivalents
Ferric sulfate : 0.03 molar equivalent Sodium peroxodisulfate: 0.9 molar equivalent Hydrochloric acid: 3 molar equivalent Water: 1700 molar equivalent After 23 hours, a cation exchange resin and an anion were used to remove excess residual metal ions. Add ion exchange resin and stir for 2 hours.

  The conductive coating composition according to the present embodiment thus obtained is an aqueous dispersion using as a seed the composite of PEDOT and crosslinked PSS. In addition to this, a compound selected from the group consisting of a water-soluble compound having an amide bond, a water-soluble compound having a hydroxyl group, a water-soluble sulfoxide, and a water-soluble sulfone is included. These are contained in order to improve the conductivity of the coating film.

  Examples of the water-soluble compound having an amide bond contained in the conductive coating composition according to the present embodiment include pyrrolidone compounds (for example, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-vinyl-2). -Pyrrolidone), amide group-containing compounds (for example, N-methylformamide, N 2, N-dimethylformamide, formamide, γ-butyrolactone, etc.) are conceivable, but are not limited thereto. Among these, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-vinyl-2-pyrrolidone, N-methylformamide, formamide, and N 2, N-dimethylformamide are preferable, and the most preferable compound is N-methylformamide. These amide compounds may be used alone or in combination of two or more.

  As a water-soluble compound having a hydroxyl group contained in the composition for conductive coating according to the present embodiment. For example, glycerol, 1,3-butanediol, ethylene glycol, diethylene glycol monoethyl ether and the like can be mentioned as suitable polyhydric alcohols. These may be used alone or in combination of two or more.

  Examples of the water-soluble sulfoxide contained in the conductive coating composition according to the present embodiment include dimethyl sulfoxide and diethyl sulfoxide.

  Examples of the water-soluble sulfone contained in the conductive coating composition according to the present embodiment include diethyl sulfone and tetramethylene sulfone.

  Further, for the purpose of improving the film formability of the conductive coating composition according to the present embodiment and the adhesion to the substrate, it may contain a water-soluble or water-dispersible binder resin.

  Examples of such a water-soluble or water-dispersible binder resin include polymer substances such as polyester, poly (meth) acrylate, polyurethane, polyvinyl acetate, polyvinylidene chloride, polyamide, and polyimide. Examples of the compound include, but are not limited to, a copolymer having a copolymer component selected from styrene, vinylidene chloride, vinyl chloride, and alkyl (meth) acrylate.

  Moreover, you may contain a small amount of surfactant in this in order to improve the wettability with respect to the base material of the electroconductive coating composition which concerns on this Embodiment.

  As such a surfactant, preferably, a nonionic surfactant (for example, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, sorbitan fatty acid ester, fatty acid alkylolamide, etc.), fluorosurfactant (For example, fluoroalkyl carboxylic acid, perfluoroalkyl benzene sulfonic acid, perfluoroalkyl quaternary ammonium, perfluoroalkyl polyoxyethylene ethanol, etc.).

  Moreover, in order to improve the wettability with respect to the base material of the conductive coating composition according to the present embodiment and to improve the drying property of the coating film, it may contain a water-soluble solvent.

  Examples of such solvents include water, methanol, ethanol, 2-propanol, n-propyl alcohol, isobutanol, ethylene glycol, propylene glycol, acetone, methyl ethyl ketone, acetonitrile, tetrahydrofuran, dioxane, and mixed solvents thereof. Although it is mentioned as a suitable solvent, it is not limited to these.

  What should be noted here is the shape of the conductive coating composition containing PEDOT and cross-linked PSS as main components in the present embodiment, which means that particles are formed.

Continue to explain further.
In the conductive coating ink composition synthesized with the conductive polymer (PEDOT) using a normal linear PSS dopant, the solid content is only about 1.3%. If you try to concentrate it, you can't concentrate it very much. Although there are some differences depending on the molecular weight of the linear PSS, if it is forcibly concentrated until the solid part becomes about 2 to 3%, the conductive coating composition using the linear PSS becomes a gelled solid. It becomes a shape. The conductive coating composition that has become a solid state, for example, remains solid even if it is applied using any solvent, so it cannot be applied satisfactorily and is difficult to put to practical use. I must.

  However, in the case of the conductive coating composition in the present embodiment, since the resulting composition forms particles at that stage, it is possible to dilute and use it as necessary at a necessary concentration. That is, there is an advantage that it can be easily used as a coating agent.

  That is, the conductive coating composition according to the present embodiment does not gel no matter how concentrated it is. For example, it can be easily concentrated to 5%, which is about twice as concentrated as the conventional conductive coating composition described above.

  Concentrating is possible, and taking advantage of the fact that the conductive coating composition does not become solid even when concentrated, the following is also possible.

  By concentrating the conductive coating composition according to the present embodiment, first, water that is a solvent of the conductive coating composition according to the present embodiment can be removed. By removing water, it becomes possible to replace the water that was originally a solvent with an organic solvent. For example, the following advantages can be obtained by using an organic solvent. First, in the case of a conventional conductive coating composition, the solvent is water, and when this is actually used for coating, there is a problem in terms of drying or the like. By substituting with a solvent, problems such as drying can be solved. By solving the problems in terms of drying and the like, those substituted with an organic solvent can be used as a conductive coating ink, and it can be said that a very useful one can be obtained. Here, further detailed description of this conductive coating ink is omitted, but in short, water that had been conventionally used as a solvent should be used as an organic solvent for the conductive coating composition according to the present embodiment. It should be noted that it can be easily replaced, and that a method of use that has been impossible in the past can be realized by replacing with an organic solvent.

Further, the description of the conductive coating composition will be continued.
As described above, the conductive coating composition according to the present embodiment may be used for a conventional transparent conductive film as an alternative to ITO, for example. That is, the conductive coating composition according to the present embodiment may require a certain degree of transmittance. For example, when used as a transparent conductive film used as a member of a solar cell or other transparent electrode, as an alternative to ITO.

  As a measure of this transmittance, when ITO is used and if a high-grade or high-grade one is required, the transmittance is desirably about 92%, but in general, A value of about 85% is also widely used, and this value can be considered as one standard. However, in the conductive coating composition according to the present embodiment, a very high level of transmittance is not necessarily essential, and it is more environmentally resistant than that, more specifically, even when exposed to water vapor or the like. It is important in the conductive coating composition according to the present embodiment to prevent a decrease in conductivity due to the disappearance of the dopant, and states that it is assumed to be used in an environment where such performance is required. deep.

  The conductive coating composition according to the present embodiment thus obtained is used as an alternative to ITO, for example, as follows. For example, a transparent conductive film can be obtained as follows.

  First, examples of the substrate to which the conductive coating composition according to the present embodiment is applied include a plastic sheet, a plastic film, a nonwoven fabric, and a glass plate. Plastics that are the raw materials for plastic sheets and plastic films include polyester, polystyrene, polyimide, polyamide, polysulfone, polycarbonate, polyvinyl chloride, polyethylene, polypropylene, blends of these, and copolymers containing these compounds. , Phenol resin, epoxy resin, ABS resin and the like. Here, a polyester film is used.

  The conductive coating composition according to the present embodiment is applied to the surface of this polyester film. Although an appropriate application method is not particularly limited, for example, a coating method such as gravure coating, roll coating, and bar coating, a printing method such as screen printing, gravure printing, flexographic printing, offset printing, and inkjet printing, a spray coating method, and dip coating. The gravure coating method is used here.

  When the coating is finished, the conductive layer is formed on the substrate surface by drying the coating layer. The conditions for drying the coating solution are 20 ° C. to 250 ° C. for 3 seconds to 1 week. Preferably, it is 70 to 130 ° C. for 5 to 60 seconds. In this embodiment mode, drying is performed at 100 ° C. for 30 seconds.

  Thus, if it is the conductive coating composition concerning this Embodiment, what produced the conductive film etc. using ITO conventionally will be limited to an expensive and complicated base film. Thus, an almost equivalent conductive film can be obtained by an inexpensive and easy wet coating method without using such a vacuum deposition method.

  Further, in the conductive coating composition according to the present embodiment described above, although not specifically described in detail here, PEDOT that can be used for the antistatic paint is of course linear PSS, which is resistant to water. Is low. In other words, it can be used as an antistatic coating without being influenced by the environment.

  Furthermore, in the conductive coating composition according to the present embodiment, although not specifically detailed here, the fact that water can be replaced with an organic solvent is as described above, so that If so, it is impossible to mix with acrylic, urethane, epoxy resin, etc., because the aqueous PEDOT / PSS that cannot be replaced with an organic solvent is used, the conductive coating composition according to the present embodiment If it is a composition substituted with an organic solvent, it can be kneaded into a resin, and therefore, an antistatic ink that can be used semipermanently can be obtained.

  In the above description, the case where PEDOT and crosslinked PSS are used as main components has been described. However, in the present invention, the conductive polymer is not limited to PEDOT and the crosslinked PSS as a dopant. It should be mentioned here that it is sufficient if a functional polymer and a water-insoluble dopant are used in combination.

  Further, the conductive coating composition according to the present invention will be described with reference to examples. In the following, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to these examples. In the following examples and comparative examples, “part” represents “part by weight”.

(Materials used)
As the polyester water-dispersed resin as the binder resin, pesresin A-645H manufactured by Takamatsu Yushi Co., Ltd., having a solid content of 20% was used.
The nonionic surfactant which is a leveling agent was Neos Co., Ltd. having a 250% solids and a solid content of 1%.
(Used equipment)
FPAR-1000, a particle size analyzer manufactured by Otsuka Electronics Co., Ltd. using a light scattering method, was used for measuring the particle size of the fine particles of the dispersion.

  The conductive coating composition according to the present invention was obtained as follows.

Example 1
1000 parts of water was added to a vessel equipped with 50 parts of styrene monomer, 1.1 parts of divinylbenzene monomer, and 3.5 parts of sodium dodecyl sulfate, and nitrogen gas was allowed to flow at 80 degrees for 30 minutes. Next, 20 parts of an aqueous solution containing 1 part of potassium peroxodisulfate was added, and the mixture was stirred at 80 ° C. for 2 hours in a nitrogen atmosphere to obtain a crosslinked polystyrene fine particle dispersion.
The solid content of the crosslinked polystyrene fine particles was 5.0%.
The particle size was 40 nm.
Next, water as a solvent for the crosslinked polystyrene fine particle dispersion was removed with an evaporator. 10 parts of powder of crosslinked polystyrene fine particles were added to 160 parts of dichloroethane solvent and completely dispersed. 30 parts of acetic anhydride and 32 parts of concentrated sulfuric acid were added to the dispersion, and the mixture was stirred in a nitrogen atmosphere at 50 ° C. for 5 hours. The obtained precipitate was filtered and washed three times with dichloroethane, and then dichloroethane was completely removed in a vacuum oven to obtain a solid. 1000 parts of water was added to the obtained solid to completely disperse the solid, and an aqueous dispersion of crosslinked PSS fine particles having a crosslinking degree of 1% was obtained.
The solid content of the crosslinked PSS fine particles was 2.9%.
The particle size was 300 nm.

2.4 parts of ethylenedioxythiophene, 446 parts of water, 5.5 parts in 215 parts of the crosslinked PSS fine particle dispersion 1% of the crosslinked PSS fine particles <1> obtained as described above. Of hydrochloric acid, 13.8 parts of 1% aqueous ferric sulfate , and 34.5 parts of 11% aqueous sodium peroxodisulfate were added. The mixture was allowed to stir at 18 ° C. for 23 hours. To this reaction mixture, 120 parts of a cation exchange resin and 220 parts of an anion exchange resin were added and stirred for 2 hours, and then the ion exchange resin was filtered off to obtain a composite of the desalted PEDOT and crosslinked PSS microparticles. A conductive polymer aqueous dispersion (solid content: 1.12%) was obtained.

  5 parts of polyester water dispersion resin, 4 parts of ethylene glycol, and 1 part of an anionic surfactant are added to 90 parts of the conductive polymer aqueous dispersion obtained by the above production method to obtain a conductive coating composition 1. Got.

(Example 2)
In the crosslinked PSS fine particles <1> in Example 1, the crosslinked PSS fine particles <2> having a different degree of crosslinking were prepared as follows. Note that the detailed description is omitted as in the previous case.
To a vessel equipped with 50 parts of styrene monomer, 3.4 parts of divinylbenzene monomer, and 3.5 parts of sodium dodecyl sulfate, 1000 parts of water was added, and nitrogen gas was allowed to flow at 80 degrees for 30 minutes. Next, 20 parts of an aqueous solution containing 1 part of potassium peroxodisulfate was added, and the mixture was stirred at 80 ° C. for 2 hours in a nitrogen atmosphere to obtain a crosslinked polystyrene fine particle dispersion.
The solid content rate of the crosslinked polystyrene fine particles was 4.4%.
The particle size was 40 nm.
Water, which is a solvent for the crosslinked polystyrene fine particle dispersion, was removed with an evaporator. 10 parts of powder of crosslinked polystyrene fine particles were added to 160 parts of dichloroethane solvent and completely dispersed.
30 parts of acetic anhydride and 32 parts of concentrated sulfuric acid were added to the dispersion, and the mixture was stirred in a nitrogen atmosphere at 50 ° C. for 5 hours. The obtained precipitate was filtered and washed three times with dichloroethane, and then dichloroethane was completely removed in a vacuum oven to obtain a solid. 1000 parts of water was added to the obtained solid to completely disperse the solid, and an aqueous dispersion of crosslinked PSS fine particles having a crosslinking degree of 3% was obtained.
The solid content of the crosslinked PSS fine particles was 3.0%.
The particle size was 100 nm.

  A conductive polymer aqueous dispersion was obtained in the same manner as in Example 1 except that the crosslinked PSS fine particles <2> obtained as described above, which was crosslinked PSS having a crosslinking degree of 3%, were used.

  To 90 parts of the conductive polymer aqueous dispersion obtained by the above production method, 5 parts of a polyester water-dispersed resin, 4 parts of ethylene glycol, and 1 part of an anionic surfactant are added to form a conductive coating composition 2 Got.

(Example 3)
Cross-linked PSS fine particles <3> having a different degree of cross-linking from the cross-linked PSS fine particles <1> and <2> were prepared as follows. Note that the detailed description is omitted as in the previous case.
To a vessel equipped with 45 parts of styrene monomer, 5 parts of divinylbenzene monomer, and 3.5 parts of sodium dodecyl sulfate, 1000 parts of water was added, and nitrogen gas was allowed to flow at 80 ° C. for 30 minutes. Next, 20 parts of an aqueous solution containing 1 part of potassium peroxodisulfate was added, and the mixture was stirred at 80 ° C. for 2 hours in a nitrogen atmosphere to obtain a crosslinked polystyrene fine particle dispersion.
The solid content rate of the crosslinked polystyrene fine particles was 4.4%.
The particle size was 40 nm.
Water, which is a solvent for the crosslinked polystyrene fine particle dispersion, was removed with an evaporator. 10 parts of powder of crosslinked polystyrene fine particles were added to 160 parts of dichloroethane solvent and completely dispersed.
30 parts of acetic anhydride and 32 parts of concentrated sulfuric acid were added to the dispersion, and the mixture was stirred in a nitrogen atmosphere at 50 ° C. for 5 hours. The obtained precipitate was filtered and washed three times with dichloroethane, and then dichloroethane was completely removed in a vacuum oven to obtain a solid. 1000 parts of water was added to the obtained solid to completely disperse the solid, and an aqueous dispersion of crosslinked PSS fine particles having a crosslinking degree of 5% was obtained.
The solid content of the crosslinked PSS fine particles was 3.4%.
The particle size was 120 nm.

  A conductive polymer aqueous dispersion was obtained in the same manner as in Example 1 except that the crosslinked PSS microparticles <3> obtained in this manner were used, and the crosslinked PSS microparticles having a crosslinking degree of 5% were used.

  5 parts of polyester water dispersion resin, 4 parts of ethylene glycol, and 1 part of an anionic surfactant are added to 90 parts of the conductive polymer aqueous dispersion obtained by the above production method, to form a conductive coating composition 3 Got.

(Comparative Example 1)
1000 parts of water was added to a vessel equipped with 50 parts of styrene monomer and 3.5 parts of sodium dodecyl sulfate, and nitrogen gas was allowed to flow for 30 minutes at 80 degrees. Next, 20 parts of an aqueous solution containing 1 part of potassium peroxodisulfate was added, and the mixture was stirred at 80 ° C. for 2 hours in a nitrogen atmosphere to obtain a polystyrene fine particle dispersion.
The solid content ratio of the polystyrene fine particle dispersion was 5.0%.
The particle size was 40 nm.
Water which is a solvent of the polystyrene fine particle dispersion was removed by an evaporator. 10 parts of polystyrene fine particle powder was added to 160 parts of dichloroethane solvent and completely dispersed.
30 parts of acetic anhydride and 32 parts of concentrated sulfuric acid were added to the dispersion, and the mixture was stirred in a nitrogen atmosphere at 50 ° C. for 5 hours. The obtained precipitate was filtered and washed three times with dichloroethane, and then dichloroethane was completely removed in a vacuum oven to obtain a solid. 1000 parts of water was added to the obtained solid to completely dissolve the solid to obtain an aqueous solution of linear PSS.
The solid content of the linear PSS aqueous solution was 5.5%.
A conductive polymer aqueous dispersion was obtained in the same manner as in Example 1 except that the linear PSS aqueous solution was used.
5 parts of a polyester water dispersion resin, 4 parts of ethylene glycol, and 1 part of an anionic surfactant were added to 90 parts of the obtained conductive polymer aqueous dispersion to obtain a conductive coating composition 4.

  The conductive coating composition obtained by Examples 1-3 and Comparative Example 1 was used as follows to obtain a conductive film.

  Using a PET film as a substrate, the coating composition was applied with a wire bar so as to have a thickness of 13.6 μm, and air-dried at 120 ° C. for 3 minutes to obtain a coated substrate having a thin film.

The following evaluation was implemented regarding the obtained electroconductive film.
-Measurement of surface resistance value The Loresta GP made from Mitsubishi Chemical Corporation was used for the measurement of surface resistance.
-Measurement of environmental resistance As a method of measuring environmental resistance, the resistance change rate was obtained from the initial resistance value and the resistance value after the environment of 60 ° C, 95% RH, 250 hours.
The lower the rate of change in resistance, the better the environmental resistance.
-Evaluation of total light transmittance The total light transmittance was measured based on JISK7361-1.

The obtained results are shown below.
Further, as Comparative Example 2, a transparent conductive film which is a so-called ITO laminated film in which ITO is laminated by a conventionally known method using a known material was prepared. Incidentally, this transparent conductive film has a configuration of PET film / ITO, the thickness of the PET film is 175 μm, and the laminated thickness of ITO is 16 nm.

  From this result, it can be seen that a conductive film using the conductive coating composition according to the present invention can exhibit the same conductivity as a conventional conductive film using ITO. Furthermore, it can be understood that the conductive coating composition according to the present invention has environmental resistance since the performance degradation is not so much observed even after exposure to a water vapor environment.

If it is the conductive coating composition demonstrated above, the layer obtained by apply | coating this conductive coating composition to the conductive layer by ITO etc. which comprises the conductive film conventionally obtained using metals, such as ITO. Even if it substitutes for, it becomes possible to obtain a conductive film having substantially the same performance and also having environmental resistance. Moreover, even if it is other than an electroconductive film, in the articles | goods which conventionally used ITO etc. as an electroconductive layer, it becomes possible to utilize as substitutes, such as ITO. If it is those articles, it becomes possible to easily impart conductivity as compared with the case of ITO metal or the like, and it is possible to make the workability easier and the production cost reduced accordingly. It becomes like this. Further, since the solvent can be easily replaced with water from an organic material, it is possible to easily obtain a conductive coating ink using the conductive coating composition according to the present invention using this property.

Claims (5)

A conductive polymer;
A dopant,
A conductive coating composition comprising as a main component,
The dopant is a crosslinked polystyrene sulfonic acid (crosslinked PSS) fine particle which is crosslinked using a crosslinking agent before being doped into the conductive polymer and has a crosslinking degree of 1% or more.
The conductive polymer is polyethylene dioxythiophene (PEDOT) which is a π-conjugated conductive polymer resin ,
A conductive coating composition characterized by the above. The conductive coating composition of claim 1, comprising:
In the conductive coating composition,
A water-soluble compound having an amide bond, a water-soluble compound having a hydroxyl group, a water-soluble sulfoxide, and a compound selected from the group consisting of water-soluble sulfones,
A conductive coating composition characterized by the above. The conductive coating composition according to any one of claims 1 to 2, comprising:
In the conductive coating composition,
In order to improve the film-forming property of the conductive coating composition and the adhesion to the substrate, it contains a water-soluble or water-dispersible binder resin.
Or / and containing a small amount of a surfactant for the purpose of improving the wettability of the conductive coating composition to the substrate,
Or / and containing a water-soluble solvent for the purpose of improving the wettability of the conductive coating composition to the substrate and improving the drying property of the coating film,
A conductive coating composition characterized by the above. Using the conductive coating composition according to any one of claims 1 to 3,
A conductive film characterized by Using the conductive coating composition according to any one of claims 1 to 3,
A conductive coating ink characterized by