JP5838876B2 - Method for forming functional thin film and functional ink - Google Patents

Description

  The present invention relates to a method for forming a functional thin film and a functional ink, and more particularly to a method for forming a functional thin film for forming a functional thin film on a substrate and a functional ink used for the method.

  Patterning functional materials on various substrates is required in a wide variety of fields, such as electronic device manufacturing.

  Conventionally, a vapor deposition method has been used for patterning a functional material. However, a vapor deposition method using a vacuum process has problems such as high apparatus cost and low material utilization efficiency.

  On the other hand, a method of directly patterning a semiconductor material by an ink jet method has been studied (Patent Documents 1 and 2). However, ink jet injection stability, flatness as a whole coating film, repelling prevention property, etc. There was a problem.

JP 2005-328030 A Special table 2008-503870

  Patent Document 1 proposes to use a ketone solvent, an ester solvent, or the like as a solvent used in a semiconductor-containing ink, and to use two or more solvents together. This is in consideration of environmental influences and device characteristics, and makes no mention of inkjet ejection stability, flatness of the entire coating film, anti-repelling property and the like. Patent Document 1 does not describe a specific example or a combination method when two kinds of solvents are used in combination, and an example in which the inkjet method is applied is a single system of anisole (boiling point 153 ° C., surface tension 35 mN / m). is there.

  Patent Document 2 discloses that an organic semiconductor-containing ink has two kinds of solvents, a solvent A having a relatively high boiling point and a good solvent for the organic semiconductor, and a solvent B having a relatively low boiling point and a poor solvent for the organic semiconductor. It is an invention that utilizes dissolution / precipitation of an organic semiconductor in an ink. Patent Document 2 refers to the surface tension of the ink as a whole, but there is no mention of providing a specific surface tension difference between two solvents. Furthermore, in Patent Document 2, the two types of solvents must be different in solubility for dissolving the organic semiconductor, and no mention is made of selecting both types of solvents from ester solvents or ketone solvents. Not.

  The present inventor has shown that, based on research, an ester-based or ketone-based solvent having a boiling point of 150 ° C. or higher and lower than 200 ° C. includes a functionalized material, in particular, a functional material having low stability in a liquid. However, with this solvent alone, an abnormal film thickness area may occur locally in the drying process of the coating film, or liquid dipping (coincidence of dots) may occur due to repelling. I learned that I couldn't draw precise drawings.

  Therefore, the present inventor has further studied diligently, and by using two or more specific solvents in combination, it is possible to improve the stability of inkjet injection and improve the flatness and the repellency of the entire coating film. Has been found to be achieved, and the present invention has been achieved.

  Accordingly, an object of the present invention is to provide a method for forming a functional thin film and a functional ink that can improve inkjet ejection stability, flatness as a whole coating film, and repellency prevention.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

1. In a method for forming a functional thin film, a functional ink containing at least a functional material and a solvent is attached to a substrate, and then the solvent is dried on the substrate to form a functional thin film.
The functional ink includes, as the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and an ester or ketone solvent having a boiling point of less than 150 ° C. A third solvent selected from the solvent group 2 consisting of a solvent and having a lower surface tension than the first solvent and an alcohol having a lower boiling point and lower surface tension than the first solvent; A method for forming a functional thin film comprising at least a solvent .

2. In a method for forming a functional thin film, a functional ink containing at least a functional material and a solvent is attached to a substrate, and then the solvent is dried on the substrate to form a functional thin film.
The functional ink includes, as the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and an ester or ketone solvent having a boiling point of less than 150 ° C. selected from solvent group 2 consisting of a solvent, and at least viewed contains a second and a solvent which is a low surface tension, the than the first solvent, in a range of less than 0.5 wt% total content of the polymer A method for forming a functional thin film, comprising:

3. In a method for forming a functional thin film, a functional ink containing at least a functional material and a solvent is attached to a substrate, and then the solvent is dried on the substrate to form a functional thin film.
The functional ink includes, as the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and an ester or ketone solvent having a boiling point of less than 150 ° C. A third solvent selected from the solvent group 2 consisting of a solvent and having a lower surface tension than the first solvent and an alcohol having a lower boiling point and lower surface tension than the first solvent; and a solvent, only at least including, a method of forming the functional thin film, wherein the total content of the polymer is in the range of less than 0.5 wt%.

4). 4. The functional thin film according to any one of 1 to 3, wherein at least one of the first solvent and the second solvent is an ester solvent or a ketone solvent having an ether bond in the molecule. Forming method.

5. 5. The method for forming a functional thin film according to any one of 1 to 4 , wherein the functional ink has a total content of a solvent selected from the solvent group 1 in a range of less than 40% by weight.

6). 6. The method for forming a functional thin film according to any one of 1 to 5 , wherein the second solvent has a boiling point of 80 ° C. or higher.

7). 7. The method for forming a functional thin film according to any one of 1 to 6 , wherein the functional ink is adhered to the heated substrate.

8). 8. The method for forming a functional thin film according to any one of 1 to 7 , wherein the functional ink is adhered to the substrate by a one-pass printing method.

9. In a functional ink containing at least a functional material and a solvent,
As the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and a solvent group 2 consisting of an ester or ketone solvent having a boiling point of less than 150 ° C. And at least a second solvent having a lower surface tension than the first solvent and a third solvent composed of an alcohol having a lower boiling point and a lower surface tension than the first solvent. A functional ink.

10. In a functional ink containing at least a functional material and a solvent,
As the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and a solvent group 2 consisting of an ester or ketone solvent having a boiling point of less than 150 ° C. more selected, and at least a look-containing second and the solvent is a low surface tension, the than the first solvent, wherein the total content of the polymer is in the range of less than 0.5 wt% Functional ink.

11. In a functional ink containing at least a functional material and a solvent,
As the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and a solvent group 2 consisting of an ester or ketone solvent having a boiling point of less than 150 ° C. And a second solvent having a lower surface tension than the first solvent and a third solvent composed of an alcohol having a lower boiling point and a lower surface tension than the first solvent. A functional ink having a total polymer content of less than 0.5% by weight .

12 12. The functional ink according to any one of 9 to 11, wherein at least one of the first solvent and the second solvent is an ester solvent or a ketone solvent having an ether bond in the molecule.

13. 13. The functional ink as described in any one of 9 to 12 , wherein the total content of the solvent selected from the solvent group 1 is in the range of less than 40% by weight.

14 14. The functional ink as described in any one of 9 to 13 , wherein the second solvent has a boiling point of 80 ° C. or higher.

  ADVANTAGE OF THE INVENTION According to this invention, the formation method and functional ink of a functional thin film which can improve inkjet injection stability, the flatness as the whole coating film, and a repellency prevention property can be provided.

The figure which shows the measurement example of the width | variety of the film thickness abnormal part in the application | coating edge part based on the two-dimensional profile of the perpendicular direction obtained by the optical interferometry

  Below, the form for implementing this invention is demonstrated.

  In the method for forming a functional thin film according to the present invention, a functional ink containing at least a functional material and a solvent is attached to a substrate, and then the solvent is dried on the substrate to form a functional thin film. Form.

  In the present invention, the functional ink contains at least two kinds of solvents including a first solvent and a second solvent as a solvent.

  The first solvent is selected from solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or higher and lower than 200 ° C.

  On the other hand, the second solvent is selected from the solvent group 2 consisting of an ester or ketone solvent having a boiling point of less than 150 ° C. and has a lower surface tension than the first solvent.

  That is, in the present invention, the first solvent has a relatively high boiling point and high surface tension, and the second solvent has a relatively low boiling point and low surface tension.

  Conventionally, in ink containing a functional material, solids are deposited or the viscosity of the ink increases as the ink evaporates in the vicinity of the nozzle hole of the inkjet head when the ink is not ejected (standby state). For this reason, the injection stability at the time of injection may not be ensured.

  In the functional ink of the present invention, even if a part of the second solvent having a relatively low boiling point has previously evaporated, the first solvent having a relatively high boiling point remains, and the inkjet injection stability is improved. It is thought that it contributes to improvement.

  Furthermore, in the drying process of the coating film (wet coating film) formed by the functional ink of the present invention, the wettability provided by the second solvent having a relatively low surface tension is as the entire coating film after drying. It is thought that it contributes to improvement of flatness and repellency prevention. Furthermore, since the drying is fast in the thin film state, the first solvent is quickly dried following the second solvent. Even if the proportion of the first solvent increases with drying, since the film is a thin film, before the failure due to the reduction in wettability due to the relatively high surface tension of the first solvent occurs, the first solvent dry. Therefore, it has been found that the influence of the surface tension of the first solvent is surprisingly small. This is also considered to contribute to the improvement of flatness and anti-repelling property as a whole coating film after drying.

  The present inventor has further studied based on the above knowledge, and in the present invention, the total of the functional inks of the solvent (including the first solvent) selected from the solvent group 1 having a relatively high boiling point and high surface tension. It has been found that setting the content in a relatively small range (specifically described later) further improves the effects of the present invention described above. It is considered that the influence (decrease in wettability) due to the relatively high surface tension of the first solvent during the drying of the thin film can be further suppressed.

  The present inventor has further studied based on the above findings, and in the present invention, the functional ink is heated to a heated substrate, preferably a relatively low temperature (specifically described later). It has been found that the effect of the present invention described above can be further improved by attaching (applying) to a substrate and forming a thin film. By applying to the heated substrate, the influence of the relatively high surface tension of the first solvent can be further suppressed, and in particular, the wettability by the second solvent is also suitable by performing the heating at a relatively low temperature. It is thought that it is expressed in.

  Hereinafter, the functional ink according to the present invention will be described in more detail.

  In the present invention, the solvent group 1 from which the first solvent is selected comprises an ester or ketone solvent having a boiling point of 150 ° C. or higher and lower than 200 ° C.

  Examples of ester solvents having a boiling point of 150 ° C. or higher and lower than 200 ° C. include 3-methoxybutyl acetate, ethylene glycol monobutyl ether acetate, propylene glycol diacetate, cyclohexanol acetate, amyl acetate, ethyl 3-ethoxypropionate, propylene glycol Monomethyl ether propionate, ethyl lactate and the like can be mentioned, among which ester solvents having an ether bond in the molecule are preferable, 3-methoxybutyl acetate, ethylene glycol monobutyl ether acetate, ethyl 3-ethoxypropionate, propylene glycol monomethyl ether Propionate is preferred and 3-methoxybutyl acetate is most preferred.

  Preferred examples of the ketone solvent having a boiling point of 150 ° C. or higher and lower than 200 ° C. include cyclohexanone, methylcyclohexanone, diisobutyl ketone, and the like, and among these, cyclohexanone is more preferable. A ketone solvent having an ether bond in the molecule can also be preferably used.

  In the present invention, the solvent group 2 from which the second solvent is selected comprises an ester or ketone solvent having a boiling point of less than 150 ° C.

  Examples of the ester solvent having a boiling point of less than 150 ° C. include propylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, and n-propyl acetate. Among them, ester solvents having an ether bond in the molecule are preferable, and propylene acetate Glycol monomethyl ether and ethylene glycol monomethyl ether acetate are preferred.

  Preferable examples of the ketone solvent having a boiling point of less than 150 ° C. include methyl ethyl ketone and methyl isobutyl ketone, and among these, 3-pentanone is more preferable. A ketone solvent having an ether bond in the molecule can also be preferably used.

  In the present invention, the second solvent is selected from the solvent group 2 having a lower surface tension than the first solvent. The surface tension is a value measured at 25 ° C. by the Wilhelmy method (plate method) using an automatic surface tension meter CVBP-Z type manufactured by Kyowa Interface Science Co., Ltd.

  In the present invention, the second solvent preferably has a boiling point of 80 ° C. or higher.

  Furthermore, in the present invention, at least one of the first solvent and the second solvent, preferably both are ester-based or ketone-based solvents having an ether bond in the molecule, and the ether bond is formed in the molecule. It is particularly preferable that it is an ester solvent.

  The functional ink according to the present invention may contain one or more other solvents in addition to the first solvent and the second solvent.

  As other solvents, alcohols such as 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, and 1-hexanol can be preferably exemplified.

  Among these, as the other solvent (third solvent), it is preferable to include an alcohol having a lower boiling point and lower surface tension than the first solvent. Thereby, the effect which can improve notably inkjet injection stability, the flatness as the whole coating film, and repellency prevention property further is acquired.

  It is also preferable that the functional ink further contains a solvent belonging to the solvent group 1 and the solvent group 2 in addition to the first solvent and the second solvent described above.

  In the functional ink according to the present invention, the total content of the solvent selected from the solvent group 1 (including the first solvent) is preferably relatively small, specifically, preferably less than 40% by weight, more Preferably it is 30 weight% or less, Most preferably, it is the range of 20 weight% or less. Thereby, inkjet injection stability, flatness as a whole coating film, and repellency prevention property are further improved, and in particular, flatness as a whole coating film and repellency prevention property are remarkably improved.

  Further, the total content of the solvent (including the first solvent) selected from the solvent group 1 in the functional ink is preferably 5% by weight or more, and more preferably 10% by weight or more. As a result, the ink jet injection stability, the flatness of the entire coating film, and the repellency can be further improved, and in particular, the ink jet injection stability is significantly improved.

  The functional material contained in the ink of the present invention is not particularly limited, but conductive materials such as conductive fine particles and conductive polymers, insulating materials, semiconductor materials, optical filter materials, dielectric materials, etc. Can be preferably exemplified.

  The conductive fine particles are not particularly limited, but Au, Pt, Ag, Cu, Ni, Cr, Rh, Pd, Zn, Co, Mo, Ru, W, Os, Ir, Fe, Mn, Ge, Sn, Ga. In particular, fine particles such as In can be exemplified, and among them, use of fine metal particles such as Au, Ag, and Cu is more preferable because a circuit pattern having low electrical resistance and strong corrosion can be formed. From the viewpoint of cost and stability, metal fine particles containing Ag are most preferable. The average particle diameter of these metal fine particles is preferably in the range of 1 to 100 nm, more preferably in the range of 3 to 50 nm.

  It is also preferable to use carbon fine particles as the conductive fine particles. Preferable examples of the carbon fine particles include graphite fine particles, carbon nanotubes, fullerenes and the like.

  Although it does not specifically limit as a conductive polymer, (pi) conjugated system conductive polymer can be mentioned preferably.

  The π-conjugated conductive polymer is not particularly limited, and includes polythiophenes (including basic polythiophenes, the same applies hereinafter), polypyrroles, polyindoles, polycarbazoles, polyanilines, polyacetylenes, polyfurans, polyparaffins. A chain conductive polymer of phenylene vinylenes, polyazulenes, polyparaphenylenes, polyparaphenylene sulfides, polyisothianaphthenes, polythiazyls can be used. Of these, polythiophenes and polyanilines are preferable in that high conductivity and good precision patterning characteristics can be obtained. Most preferred is polyethylene dioxythiophene.

  More preferably, the conductive polymer used in the present invention comprises the above-described π-conjugated conductive polymer and a polyanion. Such a conductive polymer can be easily produced by chemical oxidative polymerization of a precursor monomer that forms a π-conjugated conductive polymer in the presence of an appropriate oxidizing agent, an oxidation catalyst, and a polyanion.

  The polyanion is a substituted or unsubstituted polyalkylene, a substituted or unsubstituted polyalkenylene, a substituted or unsubstituted polyimide, a substituted or unsubstituted polyamide, a substituted or unsubstituted polyester, and a copolymer thereof. It consists of a structural unit having a group and a structural unit having no anionic group.

  This polyanion is a solubilized polymer that solubilizes the π-conjugated conductive polymer in a solvent. The anion group of the polyanion functions as a dopant for the π-conjugated conductive polymer, and improves the conductivity and heat resistance of the π-conjugated conductive polymer.

  The anion group of the polyanion may be a functional group capable of undergoing chemical oxidation doping to the π-conjugated conductive polymer. Among them, from the viewpoint of ease of production and stability, a monosubstituted sulfate group, A monosubstituted phosphate group, a phosphate group, a carboxy group, a sulfo group and the like are preferable. Furthermore, from the viewpoint of the doping effect of the functional group on the π-conjugated conductive polymer, a sulfo group, a monosubstituted sulfate group, and a carboxy group are more preferable.

  Specific examples of polyanions include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacrylic acid ethyl sulfonic acid, polyacrylic acid butyl sulfonic acid, poly-2-acrylamido-2-methylpropane sulfonic acid, polyisoprene sulfone. Examples include acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly-2-acrylamido-2-methylpropane carboxylic acid, polyisoprene carboxylic acid, polyacrylic acid and the like. . These homopolymers may be sufficient and 2 or more types of copolymers may be sufficient.

  Moreover, the polyanion which has F (fluorine atom) in a compound may be sufficient. Specifically, Nafion (made by Dupont) containing a perfluorosulfonic acid group, Flemion (made by Asahi Glass Co., Ltd.) made of perfluoro vinyl ether containing a carboxylic acid group, and the like can be mentioned.

  Among these, a compound having a sulfonic acid is more preferable because ink ejection stability is particularly good and high conductivity is obtained.

  Furthermore, among these, polystyrene sulfonic acid, polyisoprene sulfonic acid, polyacrylic acid ethylsulfonic acid, and polyacrylic acid butylsulfonic acid are preferable. These polyanions have the effect of being excellent in conductivity.

  The degree of polymerization of the polyanion is preferably in the range of 10 to 100,000 monomer units, and more preferably in the range of 50 to 10,000 from the viewpoint of solvent solubility and conductivity.

  A commercially available material can also be preferably used for the conductive polymer. For example, a conductive polymer (abbreviated as PEDOT / PSS) made of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid is H.264. C. It is commercially available from Starck as the CLEVIOS series, from Aldrich as PEDOT-PASS 483095, 560598, and from Nagase Chemtex as the Denatron series. Polyaniline is also commercially available from Nissan Chemical as the ORMECON series.

  The insulating material is not particularly limited, but is silicon such as silicon oxide (SiOX), silicon nitride (SiNX), silicon oxynitride (SiOXNY; where X> Y), silicon nitride oxide (SiNXOY; where X> Y), or the like. Preferred examples include materials, organic insulating resins such as phenol resins and polyimide resins.

  The semiconductor material is not particularly limited, but organic semiconductor materials such as polythienylene vinylene, poly (2,5-thienylene vinylene), polyacetylene, polyacetylene derivatives, and polyarylene vinylene can be preferably exemplified.

  It is particularly preferable to use the functional ink and the method for forming a functional thin film of the present invention for forming an organic layer thin film of an organic EL panel (organic EL element).

  The organic EL element has a configuration in which one or a plurality of organic compound layers are laminated between electrodes. For example, the organic EL device has the above-described configuration. In addition to the above, an electron blocking layer, a hole blocking layer, and a buffer layer Necessary layers and the like are stacked in a predetermined layer order so that carriers such as holes and electrons injected from both electrodes are smoothly moved.

  The organic EL element has various organic layer configurations. In the simplest configuration, it consists of an anode / a light emitting layer / a cathode, and, if necessary, for example, other than the above, an electron transport layer, an electron blocking layer. A layer, a hole transport layer, a hole blocking layer, a buffer layer, and the like are appropriately laminated in a predetermined layer order. Typically, for example, an element comprising a constituent layer such as an anode / hole transport layer / light emitting layer / electron transport layer / cathode is common.

  The organic EL element has a structure in which one or a plurality of organic layers are stacked between electrodes as described above, and emits light by injecting carriers such as holes and electrons from both electrodes.

  The method for forming a functional ink and a functional thin film of the present invention is particularly preferably used for coating formation of a light emitting layer, a hole injection / transport layer, an electron injection / transport layer, or the like.

  At this time, for example, the organic light emitting material contained in the light emitting layer includes aromatic heterocyclic compounds such as carbazole, carboline, diazacarbazole, triarylamine derivatives, stilbene derivatives, polyarylenes, aromatic condensed polycyclic compounds , Aromatic hetero-fused ring compounds, metal complex compounds, etc., and single or complex oligo compounds thereof, and polymer materials such as the aforementioned polyfluorenes and polyvinyl carbazoles. A widely known material can be used.

  In addition to the organic light emitting material, the organic light emitting material may preferably contain about 0.1 to 20% by weight of a dopant. As the dopant, known fluorescent dyes such as perylene derivatives and pyrene derivatives are known. In the case of a phosphorescent light emitting layer, for example, tris (2-phenylpyridine) iridium, bis (2-phenylpyridine) ( A complex compound such as an orthometalated iridium complex represented by acetylacetonato) iridium, bis (2,4-difluorophenylpyridine) (picolinato) iridium, etc. is similarly contained in an amount of about 0.1 to 20% by mass. Is preferred.

  Examples of materials used in the hole injection / transport layer include phthalocyanine derivatives, heterocyclic azoles, aromatic tertiary amines, polyvinyl carbazole, polyethylene dioxythiophene / polystyrene sulfonic acid (PEDOT: PSS), and the like. Polymer materials such as conductive polymers are also used for the light emitting layer, for example, carbazole-based light emitting materials such as 4,4′-dicarbazolylbiphenyl, 1,3-dicarbazolylbenzene, (di ) Low molecular light emitting materials represented by pyrene-based light emitting materials such as azacarbazoles, 1,3,5-tripyrenylbenzene, polymer light emitting materials represented by polyphenylene vinylenes, polyfluorenes, polyvinyl carbazoles, etc. Etc.

  Examples of the electron injection / transport layer material include metal complex compounds such as 8-hydroxyquinolinate lithium and bis (8-hydroxyquinolinate) zinc, and nitrogen-containing five-membered ring derivatives listed below. That is, oxazole, thiazole, oxadiazole, thiadiazole or triazole derivatives are preferred. These polymeric materials are also preferred. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1 -Phenyl) -1,3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) 1,3,4-oxadiazole, 2,5-bis ( 1-naphthyl) -1,3,4-oxadiazole, 1,4-bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1 , 3,4-thiadiazole, 1,4-bis [2- (5-phenyl) Asiazolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1,3,4 -Triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

  Moreover, it is particularly preferable to use the functional ink and the method for forming a functional thin film of the present invention for forming an organic thin film of an organic TFT.

  As an example of the TFT creation process, a method of sequentially forming a gate electrode formation, a gate insulating film formation, a source and drain electrode formation, a semiconductor layer formation, and a protective film formation on a substrate is known. It is particularly preferable to form the semiconductor layer using the functional ink and the method for forming a functional thin film of the invention.

  The semiconductor material may be an organic polymer material as well as a low molecular weight organic material provided with a soluble side chain to increase solubility. A TFT can be manufactured.

  Low molecular weight semiconductor materials include solubility in organic solvents such as silyl groups, ferrocenyl groups, silylalkyl groups, silylalkoxy groups, silylalkenyl groups, ferrocenylalkyl groups, ferrocenylalkoxy groups, and ferrocenylalkenyl groups. Acenes to which substituents for improvement are added are preferred. As the acene material, pentacene, tetracene, anthracene, anthradithiophene, benzothienobenzothiophene and the like are preferable.

  Examples of the π-conjugated polymer and oligomer include thiophene, vinylene, thienylene vinylene, phenylene vinylene, p-phenylene, a substituted product thereof, or two or more of these repeating units, and the number (n) of the repeating units is 2. At least one selected from the group consisting of an oligomer of ˜15, a polymer having the repeating unit number (n) of 20 or more, or a condensed polycyclic aromatic compound such as pentacene is preferable. A material having a three-dimensional regular structure by adding a substituent such as a C4 to C15 alkyl group to at least one of the repeating units is preferable.

  The optical filter material is not particularly limited, and for example, materials that form hues of yellow, magenta, cyan, black, blue, green, and red are preferably used, and particularly preferably yellow, magenta, cyan, and black materials. It is. Further, the material is not necessarily limited to a material having optical properties in the visible light region, and a material having optical properties in an invisible light region such as ultraviolet light and infrared light may be used. In addition to a material having a function of changing the intensity in a specific wavelength region, a material having a function of changing polarization characteristics may be used. Moreover, the material which expresses optical characteristics, such as light emission, by provision of excitation energy etc. may be sufficient.

  As the optical filter material, pigments, dyes and the like can be preferably used.

  As the pigment, conventionally known pigments can be used without particular limitation, and any of water-dispersible pigments, solvent-dispersible pigments and the like can be used. For example, organic pigments such as insoluble pigments and lake pigments, and inorganic pigments such as carbon black A pigment can be preferably used. This pigment is present in a dispersed state in the water-based ink, and any of self-dispersion, activator dispersion, polymer dispersion, and microcapsule dispersion may be used as this dispersion method, but polymer dispersion and microcapsule dispersion are fixable. From the point of view, it is preferable.

  Although it does not specifically limit as an insoluble pigment, For example, azo, azomethine, methine, diphenylmethane, triphenylmethane, quinacridone, anthraquinone, perylene, indigo, quinophthalone, isoindolinone, isoindoline, azine, oxazine, thiazine, dioxazine , Thiazole, phthalocyanine, diketopyrrolopyrrole and the like are preferable.

  Specific pigments that can be preferably used include the following pigments.

  Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 15: 3, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the pigment for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  When red, green, blue and intermediate colors are required in addition to the above pigments, the following pigments are preferably used alone or in combination. I. Pigment Red; 209, 224, 177, 194, C.I. I. Pigment Orange; 43, C.I. I. Vat Violet; 3, C.I. I. Pigment Violet; 19, 23, 37, C.I. I. Pigment Green; 36, 7, C.I. I. Pigment Blue; 15: 6 or the like is used.

  Examples of black pigments include C.I. I. Pigment Black; 1, C.I. I. Pigment Black; 6, C.I. I. Pigment Black; 7 etc. are mentioned.

  Examples of the dye include azo dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, phthalocyanine dyes, triphenylmethane dyes, diphenylmethane dyes and the like. Specific examples of such compounds include JP-A-2002-264490. And the dyes exemplified in the publication.

  For oil-soluble dyes that form colored fine particles together with polymers and the like and become colorants, dyes that are soluble in organic solvents that do not have water-soluble groups such as carboxylic acids and sulfonic acids and are insoluble in water, for example, dispersed A dye or the like is selected. Also included are dyes that exhibit oil solubility by salting a water-soluble dye with a long-chain base. For example, acid dyes, direct dyes, salt-forming dyes of reactive dyes and long-chain amines are known. .

  Although it does not specifically limit as a dielectric material, A silicon oxide, an alumina oxide, a titanium oxide, niobium oxide, a tantalum oxide, a tin oxide etc. can be illustrated preferably.

  Further, various polymer materials can be used as the dispersion resin of the functional material or as the binder of the functional material.

  The functional ink according to the present invention preferably has a total polymer content of less than 0.5% by weight. The polymer contained in the functional ink of the present invention is usually derived from the functional material described above. The polymer generally means a polymer having a molecular weight of 10,000 or more, and a compound having a molecular weight of 1,000 or more and less than 10,000 is treated as a quasi-polymer. However, in the present invention, a polymer includes a quasi-polymer and has a molecular weight of 1000 or more.

  In the present invention, the functional material preferably has high solubility in both the first solvent and the second solvent, and preferably in both the first solvent and the second solvent. Preferably has a high solubility of 0.3 g / l or more, more preferably 5 g / l or more. In the present invention, the functional material may be one having higher solubility in the second solvent than the first solvent, or in the first solvent rather than the second solvent. It may exhibit high solubility.

  In the present invention, the substrate on which the functional ink is applied and the coating film is formed is not particularly limited, and may be light transmissive or light opaque. For example, a glass substrate, a resin substrate, a resin film and the like can be preferably exemplified in terms of excellent hardness as a base material and ease of formation of a conductive layer on the surface, but it is lightweight and flexible. It is preferable to use a resin film from the viewpoints of being excellent and inexpensive.

  The resin film used as the substrate in the present invention is not particularly limited, and the material, shape, structure, thickness and the like can be appropriately selected from known ones. For example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate, modified polyester resin film such as modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, polystyrene resin film, cyclic olefin resin Polyolefin resin films such as polyvinyl chloride, polyvinyl resin such as polyvinyl chloride, polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate ( PC) resin film, polyamide resin film, polyimide resin film, acrylic resin film, triacetyl cellulose (TAC) resin film, etc. It can be.

  Above all, from the viewpoint of being chemically stable, small in manufacturing variations, and inexpensive, biaxially stretched polyethylene terephthalate, biaxially stretched polyethylene naphthalate film, polyethersulfone film, polycarbonate film, polyimide resin film The biaxially stretched polyethylene terephthalate and the biaxially stretched polyethylene naphthalate film are more preferable.

  In the present invention, the substrate is preferably pretreated from the viewpoint of precision patterning characteristics. Preferred examples of the pretreatment include application of an adhesive layer, application of a water repellent layer, corona discharge, plasma irradiation, UV irradiation, and the like.

  As an inkjet head used for coating film formation with the functional ink of the present invention, any of existing methods such as a piezo method, a thermal method, and a continuous method may be used, but when the ink according to the present invention is used. It is preferable to use a piezo method from the viewpoint of further suitably improving the injection stability.

  The volume of ink droplets ejected from the head is preferably in the range of 0.5 pl to 100 pl. From the viewpoint of reducing coating unevenness and increasing the printing speed, the range of 2 pl to 20 pl is more preferable. The volume of the ink droplet can be adjusted as appropriate by adjusting the applied voltage.

  The printing resolution is preferably in the range of 180 dpi to 10000 dpi, more preferably in the range of 360 dpi to 2880 dpi, and can be appropriately set in consideration of the wet film thickness, the volume of the ink droplets, and the like.

  In the present invention, the wet film thickness of the wet coating film at the time of inkjet application (immediately after application) can be appropriately set, but is preferably in the range of 1 μm to 100 μm, more preferably in the range of 1 μm to 30 μm, and most preferably 1 μm. In the range of ˜5 μm, the effect of the present invention is more remarkably exhibited. The wet film thickness can be calculated from the application area, printing resolution, and ink droplet volume.

  Ink jet printing methods include a one-pass printing method and a multi-pass printing method.

  The one-pass printing method is a method for printing a predetermined printing area by one head scan. On the other hand, the multi-pass printing method is a method of printing a predetermined print area by a plurality of head scans.

  As described above, the functional ink of the present invention has a more remarkable effect when a coating film is formed using the one-pass printing method.

  In the one-pass printing method, it is preferable to use a wide head in which nozzles are arranged in parallel over a width equal to or larger than the width of a desired coating pattern. When forming a plurality of independent coating patterns whose patterns are not continuous with each other on the same base material, a wide head having at least the width of each coating pattern may be used.

  In addition, when the parallel arrangement width of the nozzles is less than the width of the application pattern, one application pattern is divided into a plurality of print areas, and one-pass printing is performed for each print area. In the ink, there is a problem that uncoated stripes are formed between adjacent regions, or the coating film is overlapped between the regions so that the uniformity of the film thickness is easily lost. On the other hand, with the functional ink according to the present invention, it has been confirmed that the effect of improving the uniformity of the film thickness can be obtained even under such printing conditions.

  In the present invention, it is also preferable that the substrate is heated at the time of printing (when the functional ink adheres to the substrate). Thereby, drying of a coating film is accelerated | stimulated, the influence (decrease in wettability) by the comparatively high surface tension of a 1st solvent is further suppressed, and a drying nonuniformity can further be reduced. As a result, in particular, the effect of further improving the flatness and anti-repellency of the coating after drying can be obtained.

  Heating is preferably performed at a relatively low temperature. Specifically, it is preferable to perform the heating so that the temperature of the substrate surface during printing is in the range of 30 ° C to 70 ° C. Thereby, the effect which further improves the flatness as a whole coating film after drying, and repelling prevention property is acquired. When it exceeds 70 ° C., drying is promoted too much, so that wettability by the second solvent is hardly expressed, and there is a possibility of causing coating unevenness.

  In the present invention, it is also preferable to provide a drying step after printing, and heat drying, blow drying, and the like can be preferably used. In the present invention, the flow of the coating solution may occur even after several seconds to several hours after coating, and therefore, it is preferable to reduce the fluidity by drying as soon as possible after coating.

  In the present invention, an example of a preferable drying step is to start drying in the range of room temperature to 70 ° C. after application, raise the drying temperature later, and dry completely at 80 ° C. or higher. The increase in drying temperature may be increased in stages or continuously.

  Examples of the present invention will be described below, but the present invention is not limited to such examples.

(Example 1)
<Preparation of ink>
After mixing the functional material and the organic solvent with the composition (% by weight) shown in Table 1, the mixture was filtered through a 0.45 μm PTFE filter, and the obtained filtrates were designated as Inks 1 to 13. It was confirmed that the composition shown in Table 1 was not substantially changed before and after filtration.

  As the functional material, a light emitting material 1 (a mixture of the following host material (90% by weight) and the following light emitting material (10% by weight)) or an organic semiconductor material 1 (the following C10-DNTT) was used. The polymer content of each functional material is 0% by weight for both the light emitting material 1 and the organic semiconductor material 1 with respect to the total weight of the functional material.

  The following evaluation was performed on each prepared ink.

1. Evaluation of repellency <Preparation of substrate>
A 10 cm square (10 cm × 10 cm) glass is washed with pure water after washing with detergent, and further using a UV-ozone cleaner for 10 minutes from a distance of 30 mm with a low-pressure mercury lamp (UV wavelength: 254 nm, 185 nm) at an illuminance of ² mW / cm ^2. Treatment was performed by UV irradiation to obtain a substrate.

<Printing>
By using an inkjet drawing apparatus equipped with an inkjet head (“KM512M” manufactured by Konica Minolta Co., Ltd.), the prepared ink is ejected onto the prepared substrate by an inkjet method, and two pattern films (each 36 mm width × 90 mm height; wet film thickness (μm) is described in Table 1.

  The drawing conditions of the ink jet method were an appropriate liquid amount of 13.0 ng (14.1 pl) by adjusting the applied voltage, a resolution of 360 dpi × 360 dpi, and one-pass printing for each pattern film.

  Further, the temperature of the substrate was kept at 50 ° C. during printing. After printing, it was dried by heating at 100 ° C. for 30 minutes on a hot plate.

  A total of 10 pattern films were continuously formed on 5 substrates, the occurrence pattern of uneven coating failure was counted, and the anti-repellency was evaluated according to the following evaluation criteria.

〔Evaluation criteria〕
Evaluation 5: No failure in 10 patterns Evaluation 4: Failure in 1 pattern Evaluation 3: Failure in 2 patterns Evaluation 2: Failure in 3-5 patterns Evaluation 1: Failure in 6 patterns or more

2. Evaluation of coating film flatness Pd vapor deposition (thickness: 1 mm) was uniformly applied to the pattern film formed in the same manner as in the evaluation of the above-mentioned anti-repelling property, and a light interference type surface shape measuring apparatus (“WYKO NT9300 manufactured by Beiko Japan Ltd.) )) Was measured based on the two-dimensional profile in the vertical direction obtained by the optical interferometry using the optical interference method, and the width of the film thickness abnormality portion at the coating end was measured and evaluated according to the following evaluation criteria.

  In addition, the example of a measurement of the width | variety of the film thickness abnormal part in the application | coating edge part based on a two-dimensional profile is as having shown in FIG.

〔Evaluation criteria〕
Evaluation 5: The width of the abnormal thickness portion is less than 50 μm Evaluation 4: The width of the abnormal thickness portion is 50 μm or more and less than 100 μm Evaluation 3: The width of the abnormal thickness portion is 100 μm or more and less than 150 μm Evaluation 2: Film The width of the abnormal thickness portion is 150 μm or more and less than 300 μm. Evaluation 1: The width of the abnormal thickness portion is 300 μm or more.

3. Evaluation of ink jet ejection stability Using an ink jet drawing apparatus equipped with an ink jet head ("KM512M" manufactured by Konica Minolta Co., Ltd.), the ink prepared above is ejected onto glossy media for ink jet (void type) by the ink jet method. A pattern of 36 mm width × 290 mm height was continuously printed.

  The drawing conditions of the ink jet method were set to 13.0 ng (14.1 pl) by adjusting the applied voltage, the resolution to 360 dpi × 360 dpi, and one-pass printing for each pattern film.

  Prints up to 100 patterns in succession, observes the landed ink with an optical microscope (100 times), and the number of nozzles with missing nozzles and nozzle bending (landing position deviation) in all nozzles (512) Were evaluated according to the following evaluation criteria.

〔Evaluation criteria〕
Evaluation 5: No missing nozzle or bent nozzle Evaluation 4: No missing nozzle, but no bent nozzle (less than 25)
Evaluation 3: No missing nozzle, but no bent nozzle (25 or more and less than 50)
Evaluation 2: Nozzle missing (less than 50)
Evaluation 1: Nozzle missing (50 or more)

4). Evaluation Table 1 shows the results of the above evaluation for each ink.

<Evaluation>
In the inks 1 to 10 according to the present invention including at least a first solvent selected from the solvent group 1 and a second solvent selected from the solvent group 2 and having a lower surface tension than the first solvent, It can be seen that the injection stability, the flatness of the coating film as a whole, and the repellency can be improved.

  In particular, it can be seen that, in the ink 3 containing alcohol as the third solvent, the inkjet ejection stability, the flatness of the entire coating film, and the repelling prevention property are remarkably improved.

  Furthermore, the contrast of the ink 1 and the ink 4 indicates that the total content of the solvent (including the first solvent) selected from the solvent group 1 is less than 40% by weight. It turns out that it is further superior.

  In contrast, in the inks 11 to 13 that do not include the first solvent selected from the solvent group 1 and the second solvent selected from the solvent group 2 and having a lower surface tension than the first solvent, It can be seen that the ink jet injection stability, the flatness of the entire coating film, and the anti-repellency are poor.

Claims (14)

In a method for forming a functional thin film, a functional ink containing at least a functional material and a solvent is attached to a substrate, and then the solvent is dried on the substrate to form a functional thin film.
The functional ink includes, as the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and an ester or ketone solvent having a boiling point of less than 150 ° C. A third solvent selected from the solvent group 2 consisting of a solvent and having a lower surface tension than the first solvent and an alcohol having a lower boiling point and lower surface tension than the first solvent; A method for forming a functional thin film comprising at least a solvent . In a method for forming a functional thin film, a functional ink containing at least a functional material and a solvent is attached to a substrate, and then the solvent is dried on the substrate to form a functional thin film.
The functional ink includes, as the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and an ester or ketone solvent having a boiling point of less than 150 ° C. selected from solvent group 2 consisting of a solvent, and at least viewed contains a second and a solvent which is a low surface tension, the than the first solvent, in a range of less than 0.5 wt% total content of the polymer A method for forming a functional thin film, comprising: In a method for forming a functional thin film, a functional ink containing at least a functional material and a solvent is attached to a substrate, and then the solvent is dried on the substrate to form a functional thin film.
The functional ink includes, as the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and an ester or ketone solvent having a boiling point of less than 150 ° C. A third solvent selected from the solvent group 2 consisting of a solvent and having a lower surface tension than the first solvent and an alcohol having a lower boiling point and lower surface tension than the first solvent; and a solvent, only at least including, a method of forming the functional thin film, wherein the total content of the polymer is in the range of less than 0.5 wt%. The functional thin film according to any one of claims 1 to 3, wherein at least one of the first solvent and the second solvent is an ester solvent or a ketone solvent having an ether bond in the molecule. Forming method. The method for forming a functional thin film according to any one of claims 1 to 4 , wherein the functional ink has a total content of a solvent selected from the solvent group 1 in a range of less than 40% by weight. The second solvent, the method of forming the functional thin film according to any one of claims 1 to 5, wherein the boiling point of 80 ° C. or higher. Method of forming a functional thin film according to any one of claims 1 to 6, characterized in that is attached to the substrate which is heated the functional ink. Method of forming a functional thin film according to any one of claims 1 to 7, characterized in that depositing a single pass printing process the functional ink on the substrate. In a functional ink containing at least a functional material and a solvent,
As the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and a solvent group 2 consisting of an ester or ketone solvent having a boiling point of less than 150 ° C. And at least a second solvent having a lower surface tension than the first solvent and a third solvent composed of an alcohol having a lower boiling point and a lower surface tension than the first solvent. A functional ink. In a functional ink containing at least a functional material and a solvent,
As the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and a solvent group 2 consisting of an ester or ketone solvent having a boiling point of less than 150 ° C. more selected, and at least a look-containing second and the solvent is a low surface tension, the than the first solvent, wherein the total content of the polymer is in the range of less than 0.5 wt% Functional ink. In a functional ink containing at least a functional material and a solvent,
As the solvent, a first solvent selected from a solvent group 1 consisting of an ester or ketone solvent having a boiling point of 150 ° C. or more and less than 200 ° C., and a solvent group 2 consisting of an ester or ketone solvent having a boiling point of less than 150 ° C. And a second solvent having a lower surface tension than the first solvent and a third solvent composed of an alcohol having a lower boiling point and a lower surface tension than the first solvent. A functional ink having a total polymer content of less than 0.5% by weight . The functional ink according to claim 9, wherein at least one of the first solvent and the second solvent is an ester solvent or a ketone solvent having an ether bond in the molecule. . Functional ink according to any one of claims 9-12 that the total content of solvent selected from the solvents group 1, characterized in that in the range of less than 40 wt%. The second solvent, functional ink according to any one of claims 9-13, wherein the boiling point of 80 ° C. or higher.

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