CN115202149A

CN115202149A - Negative radiation-sensitive resin composition, insulating film for organic electroluminescent element, method for forming the same, and organic electroluminescent device

Info

Publication number: CN115202149A
Application number: CN202210355644.7A
Authority: CN
Inventors: 西川(鬼丸)奈美; 秋池利之; 田崎太一; 山口佳久; 大友谅平
Original assignee: JSR Corp
Current assignee: JSR Corp
Priority date: 2021-04-07
Filing date: 2022-04-06
Publication date: 2022-10-18
Also published as: KR20220139241A; JP2022161019A

Abstract

The present invention addresses the problem of providing a negative radiation-sensitive resin composition that has sufficient lithography performance and can form a cured film having sufficient resistance to chemicals and oxidation and ashing resistance even when heated at relatively low temperatures, an insulating film for an organic electroluminescent element, a method for forming the same, and an organic electroluminescent device. The present invention is a negative radiation-sensitive resin composition containing (A) a polysiloxane having at least one thiol group, (B) a polyfunctional methacrylate, and (C) a photopolymerization initiator, and having a viscosity of 0.5 mPas to 100 mPas measured at 25 ℃ and 50rpm with an E-type viscometer.

Description

Negative radiation-sensitive resin composition, insulating film for organic electroluminescent element, method for forming the same, and organic electroluminescent device

Technical Field

The present invention relates to a negative radiation-sensitive resin composition, an insulating film for an organic EL element, a method for forming an insulating film for an organic EL element, and an organic EL device.

Background

As one of light-emitting elements which have been developed in recent years, an organic Electroluminescence (EL) element having a laminated structure including an anode layer, an organic light-emitting layer, and a cathode layer is known. As a display device having an organic EL element, a touch panel-equipped organic EL device having a touch panel provided on the front surface of the device is known (see patent document 1).

The organic EL device with a touch panel is manufactured by bonding the touch panel to a substrate on which an organic EL element is formed, for example, via an adhesive layer. A touch panel is generally manufactured by providing a touch panel member such as a sensor electrode on a support substrate for a touch panel.

On the other hand, patent document 2 discloses a curable resin composition containing silsesquioxane having a thiol group and a compound having a plurality of allyl groups, and describes that the composition can be used for forming a coating layer or an adhesive layer such as a liquid crystal panel or an EL panel. Patent document 3 discloses a photosensitive composition containing a polysiloxane having a thiol group and a multifunctional acrylate compound, and describes that durability of a pattern film is improved by forming the pattern film on a substrate using the composition.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. 2015-161806

[ patent document 2] Japanese patent laid-open No. 2012-180464

[ patent document 3] Japanese patent application laid-open No. 2010-039056

Disclosure of Invention

[ problems to be solved by the invention ]

As described above, when the touch panel is bonded to the substrate on which the organic EL element is formed via the adhesive layer, the thickness of the entire organic EL device with the touch panel increases. In the case of a thick device, breakage or functional deterioration is likely to occur when the device is bent. In addition, thinning itself is desired for various display devices. Therefore, it is considered that the thickness of the entire display device such as an organic EL device with a touch panel can be reduced by directly providing the touch panel on the substrate on which the organic EL element is formed by photolithography, etching, or the like.

However, in the conventional method using a material containing a polyfunctional (meth) acrylate or the like as a hardening component, it is necessary to heat at a temperature exceeding 100 ℃, preferably exceeding 120 ℃, at the time of hardening an insulating film for forming a touch panel. When an insulating film is formed on a substrate on which an organic EL element is formed, there is a problem that an organic light-emitting layer deteriorates due to heating at a temperature exceeding 100 ℃, particularly exceeding 120 ℃.

On the other hand, when an insulating film is formed by heating at 120 ℃ or lower, particularly at 100 ℃ or lower using conventional materials, the obtained insulating film cannot withstand an etching solution or oxygen ashing (oxygen ashing) for forming wiring, and thus it tends to be difficult to fabricate a touch panel structure. In various applications such as insulating films for other display devices, not only insulating films for touch panel-equipped organic EL devices, but also insulating films for other display devices, it is desired to develop radiation-sensitive resin compositions that can provide insulating films having sufficient resistance to etching chemicals and resistance to oxidative ashing even when heated at relatively low temperatures.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a negative radiation-sensitive resin composition having sufficient lithography performance and capable of obtaining a cured film having sufficient chemical resistance and oxidation/ashing resistance even by heating at a relatively low temperature (for example, 120 ℃ or lower), an insulating film for an organic EL element and an organic EL device obtained using the negative radiation-sensitive resin composition, and a method for forming an insulating film for an organic EL element using the negative radiation-sensitive resin composition.

[ means for solving problems ]

The invention to solve the above problems is a negative radiation-sensitive resin composition according to the following [ 1] or [ 2],

[ 1] A negative radiation-sensitive resin composition comprising (A) a polysiloxane having at least one thiol group, (B) a polyfunctional methacrylate, and (C) a photopolymerization initiator.

A negative radiation-sensitive resin composition comprising (A) a polysiloxane having at least one thiol group, (B) a polyfunctional methacrylate, and (C) a photopolymerization initiator, and having a viscosity of 0.5 to 20 mPas as measured at 25 ℃ and 50rpm with an E-type viscometer.

Another invention to solve the above problems is an insulating film for an organic EL device, which is formed from the negative radiation-sensitive resin composition according to the above [ 1] or [2 ].

In order to solve the above problem, another invention provides a method for forming an insulating film for an organic EL element, including: a step of forming a coating film by directly or indirectly applying the negative radiation-sensitive resin composition according to [ 1] or [ 2] onto a substrate; a step of irradiating at least a part of the coating film with radiation after the step of forming the coating film; a step of developing the coating film after the step of irradiating the radiation; and heating the coating film at a temperature of 60 ℃ to 120 ℃ after the developing step.

In order to solve the above problem, a further aspect of the present invention is an organic EL device including the insulating film for an organic EL element.

[ Effect of the invention ]

According to the present invention, there can be provided a negative radiation-sensitive resin composition having sufficient lithography performance and capable of obtaining a cured film having sufficient chemical resistance and oxidation/ashing resistance even by heating at a relatively low temperature, an insulating film for an organic EL element and an organic EL device obtained using the negative radiation-sensitive resin composition, and a method for forming an insulating film for an organic EL element using the negative radiation-sensitive resin composition.

Further, when the curable resin composition described in patent document 2 contains a compound having a plurality of allyl groups, the reactivity of the allyl groups is low, and only the ene-thiol reaction proceeds. In contrast, the negative radiation-sensitive resin composition of the present invention contains a polyfunctional methacrylate, and therefore, the polymerization reaction of the methacrylate group-based ene-thiol with a general radical polymerization proceeds simultaneously. Therefore, according to the present invention, a cured film having more excellent low-temperature curability and more excellent solvent resistance can be obtained.

Further, when the photosensitive composition described in patent document 3 contains a polyfunctional acrylate, the reactivity of the acrylate group is excellent, and on the other hand, since an ene-thiol reaction proceeds during storage of the composition, the viscosity of the composition increases, and the storage stability is poor. In contrast, the negative radiation-sensitive resin composition of the present invention contains a polyfunctional methacrylate, and therefore, can provide a composition having excellent storage stability.

Drawings

Fig. 1 is a cross-sectional view schematically showing an organic EL device according to an embodiment of the present invention.

[ description of symbols ]

10: organic EL device

20: organic EL display substrate

21: supporting substrate

22: anode layer

23: organic light emitting layer

24: cathode layer

25: adhesive layer

26: sealing substrate

30: touch screen

31: first sensor electrode

32: second sensor electrode

33: insulating film

34: transparent substrate

Detailed Description

< negative radiation-sensitive resin composition >

A negative radiation-sensitive resin composition according to an embodiment of the present invention is a negative radiation-sensitive resin composition containing (a) a polysiloxane having at least one thiol group (hereinafter also referred to as "component (a)"), (B) a polyfunctional methacrylate (hereinafter also referred to as "component (B)"), and (C) a photopolymerization initiator (hereinafter also referred to as "component (C)"), and preferably having a viscosity of 0.5mPa · s or more and 20mPa · s or less as measured with an E-type viscometer at 25 ℃ and 50 rpm.

According to the negative radiation-sensitive resin composition, by containing the component (a), the component (B) and the component (C), and preferably having the viscosity in the above range, a cured film having sufficient photolithography performance and sufficient resistance to chemical liquid and oxidation ashing even by heating at a relatively low temperature can be obtained. The reason for this is not clear, but is presumed as follows. That is, it is presumed that in the negative radiation-sensitive resin composition, the thiol group of the polysiloxane functions as an alkali-soluble group and a crosslinking group, and thus the dissolution contrast of the cured film obtained is improved, thereby exhibiting excellent lithographic performance. In addition, a cured film having a structure in which a siloxane structure coexists with a methacrylic structure can be obtained by forming a crosslinked structure by an ene-thiol reaction between a polysiloxane having a siloxane structure and a polyfunctional methacrylate having a methacrylic structure. Therefore, it is presumed that the obtained cured film is excellent in stress relaxation and exhibits chemical resistance and oxidation and ashing resistance. Hereinafter, each component of the negative radiation-sensitive resin composition will be described.

(A) Polysiloxanes with at least one thiol group

The negative radiation-sensitive resin composition contains (A) a polysiloxane having at least one thiol group. The negative radiation-sensitive resin composition contains a compound having two or more functional groups reactive with a thiol group in one molecule ((B) polyfunctional methacrylate) in addition to the component (A), and the component (A) and the component (B) react with each other, whereby an insulating film having excellent curability can be formed. The component (A) is a polysiloxane having a siloxane bond.

The negative radiation-sensitive resin composition contains a polysiloxane having a siloxane bond, thereby suppressing the occurrence of outgassing during the production of an insulating film, and obtaining an insulating film for an organic EL element having excellent coating properties and transparency of the insulating film.

In addition, the compound having a thiol group can be photo-hardened by an ene-thiol reaction with the compound having a carbon-carbon double bond. The ene-thiol reaction has advantages such as proceeding by ultraviolet irradiation regardless of the presence or absence of a polymerization initiator, no reaction inhibition by oxygen, and a reduction in curing shrinkage, compared with a radical polymerization system generally used in a photo-curing system.

(A) The component (b) is a compound obtained by hydrolyzing and condensing a thiol group-containing alkoxysilane (a 1) (hereinafter, also referred to as "component (a 1)") represented by the following formula (2).

R ¹ Si(OR ² ) ₃ (2)

In the formula (2), R ¹ Represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms and at least one thiol group, or an aromatic hydrocarbon group having 6 to 8 carbon atoms and at least one thiol group, R ² Represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms.

The aliphatic hydrocarbon group having 1 to 8 carbon atoms may be straight or branched. Examples thereof include: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl.

The term "aromatic hydrocarbon group" in the aromatic hydrocarbon group having 6 to 8 carbon atoms is a concept including not only a group including only a ring structure but also a group in which a divalent aliphatic hydrocarbon group is further substituted in the ring structure, as long as the structure includes at least an alicyclic hydrocarbon or an aromatic hydrocarbon. Examples thereof include: phenyl, benzyl, phenethyl, tolyl, xylyl.

Wherein, as R ¹ From the viewpoint of low-temperature curability, an aliphatic hydrocarbon group having 1 to 6 carbon atoms and having at least one thiol group is preferable, and R is preferably R ² From the viewpoint of hydrolyzability, an aliphatic hydrocarbon group having 1 to 3 carbon atoms is preferred.

Specific examples of the component (a 1) represented by the formula (2) include: 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropyltributoxysilane, 1,4-dimercapto-2- (trimethoxysilyl) butane, 1,4-dimercapto-2- (triethoxysilyl) butane, 1,4-dimercapto-2- (tripropoxysilyl) butane, 1,4-dimercapto-2- (tributoxysilyl) butane, 2-mercaptomethyl-3-mercaptopropyltrimethoxysilane, 2-mercaptomethyl-3-mercaptopropyltriethoxysilane, 2-mercaptomethyl-3-mercaptopropyltripropoxysilane, 2-mercaptomethyl-3-mercaptopropyltributoxysilane, 1,2-dimercaptoethyltrimethoxysilane, 1,2-dimercaptoethyltriethoxysilane, 1,2-dimercaptoethyltripropoxysilane, 1,2-dimercaptoethyltriethoxysilane, and the like, and any of these compounds can be used alone or in combination. Among the above-mentioned exemplary compounds, 3-mercaptopropyltrimethoxysilane is particularly preferable because it has high reactivity in hydrolysis reaction and is easily available.

In addition to the component (a 1), alkyltrialkoxysilanes (a 2) (hereinafter, also referred to as "component (a 2)") such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, etc. may be used. The component (a 2) may be used alone or in combination of two or more. Since the content of thiol groups can be adjusted by using these, the refractive index of the finally obtained insulating film can be adjusted.

When the component (a 1) and the component (a 2) are used in combination, the molar ratio [ the number of moles of the component (a 2) ]/[ the total number of moles of the component (a 1) and the component (a 2) ] (molar ratio) is preferably 0.7 or less, more preferably 0.5 or less. When the molar ratio exceeds 0.7, the number of thiol groups contained in the obtained component (a) is reduced, so that the hardening properties of the insulating film may be reduced and the effect of improving physical properties such as hardness of the insulating film may be insufficient. On the other hand, the molar ratio may be 0, but may exceed 0 and be set as appropriate.

(A) Component (a 1) may be used alone or in combination with component (a 2), and these are hydrolyzed and then condensed to obtain the component (a). The alkoxy group contained in the component (a 1) or the component (a 2) is converted into a silanol group by the hydrolysis reaction, and an alcohol is produced as a by-product. The amount of water required for the hydrolysis reaction may be, for example, an amount of [ the number of moles of water used in the hydrolysis reaction ]/[ the total number of moles of the alkoxy groups contained in the component (a 1) and the component (a 2) ] (molar ratio) of 0.4 to 10. When the molar ratio is 0.4 or more and less than 0.5, a part of the alkoxy groups remain in the obtained component (a), but the adhesion to the inorganic material is improved. In addition, when the molar ratio is 0.5 or more and 10 or less, since substantially no alkoxy group remains in the obtained component (a), a thick cured product can be easily produced. On the other hand, when the molar ratio is less than 0.4, the alkoxy group remaining in the component (a) without hydrolysis is too large, and therefore a large amount of volatile components is generated during curing, and it is difficult to form a thick cured product, which is not preferable. In addition, when the molar ratio exceeds 10, the amount of water to be removed in the condensation reaction (dehydration reaction) to be carried out later becomes large, which is economically disadvantageous.

As the catalyst used in the hydrolysis reaction, an acidic catalyst which is conventionally known to function as a hydrolysis catalyst can be arbitrarily used. However, since it is necessary to substantially remove the acidic catalyst after the hydrolysis reaction, a catalyst that is easily removed is preferable. As such a substance, formic acid which can be removed by pressure reduction is preferable because of high catalytic activity and low boiling point. Examples of the catalyst include solid acid catalysts which can be easily removed by filtration or the like and are insoluble in the component (a 1) and the component (a 2), hydrolysates thereof, solvents used in hydrolysis, and water. As the solid acid catalyst, there may be mentioned: cation exchange resin, activated clay, carbon-based solid acid, and the like. Among them, the cation exchange resin is preferable because of high catalytic activity and easy availability. As the cation exchange resin, a strong acid type cation exchange resin or a weak acid type cation exchange resin can be used. Examples of the strong acid type ion exchange resin include: the Daya ion (Diaion) SK series, the Daya ion (Diaion) UBK series, the Daya ion (Diaion) PK series, the Daya ion (Diaion) HPK 25. PCP series (both trade names made by Mitsubishi chemical corporation), an Mbo Latet (Amberlite) IR120B, an Mbo Latet (Amberlite) IR124, an Mbo Latet (Amberlite) 200CT, an Mbo Latet (Amberlite) 252, an Mbo Jant (Amberjft) 1020, an Mbo Jant (Amberjet) 1024, an Mbo Jant (Amberjet) 1060 82 Jant (Amxberg 3282 Jant) 1220, 34 zxft 3434 Jant (Amberlite) Y, 3264 zxft 3238 Jant (Amberlite) 3238, 3624, and the like are all made by Axbert 3724, 3624 zberg 3724, 3624, and 3624. Examples of the weak acid type ion exchange resin include: da ya ion (Diaion) WK series, da ion (Diaion) WK40 (both trade names manufactured by mitsubishi chemical corporation), an Mbo leite (Amberlite) FPC3500, an Mbo leite (Amberlite) IRC76 (both trade names manufactured by ogano (goro)). The type of ion exchange resin used may be arbitrarily selected depending on the reaction rate, suppression of side reactions, or the like, but a strongly acidic ion exchange resin is particularly preferable in terms of reactivity.

The amount of the acidic catalyst added is preferably 0.1 part by mass or more and 25 parts by mass or less, and more preferably 1 part by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total of the component (a 1) and the component (a 2). When the amount of the additive exceeds 25 parts by mass, the additive tends to be difficult to remove in a subsequent step or to be economically disadvantageous. On the other hand, when the amount is less than 0.1 part by weight, the reaction tends to be substantially not progressed, or the reaction time tends to be prolonged.

The reaction temperature and the reaction time can be arbitrarily set according to the reactivity of the component (a 1) or the component (a 2). The reaction temperature is usually about 0 ℃ to 100 ℃ inclusive, and preferably about 20 ℃ to 60 ℃ inclusive. The reaction time is from 1 minute to 2 hours. The hydrolysis reaction may be carried out in the presence or absence of a solvent, but preferably no solvent is used. When a solvent is used, the kind of the solvent is not particularly limited, and one or more kinds of arbitrary solvents can be selected and used, but it is preferable to use the same solvent as used in the condensation reaction described later.

After the hydrolysis reaction is completed, condensation is performed using an acidic catalyst or a basic catalyst. Any dehydration condensation catalyst known in the art may be used in the condensation reaction. In the case of using an acid catalyst, formic acid is preferred because it has high catalytic activity and can be used in common with a catalyst for hydrolysis reaction. The reaction temperature and the reaction time can be arbitrarily set depending on the reactivity of the component (a 1) or the component (a 2). The reaction temperature is usually 40 ℃ or higher and 150 ℃ or lower, preferably 60 ℃ or higher and 100 ℃ or lower. The reaction time is 30 minutes to 12 hours.

When a basic catalyst is used, the acidic catalyst needs to be removed from the system after the completion of the hydrolysis reaction, and therefore, the acidic catalyst is removed by a method such as pressure reduction or filtration. In addition, the acidic catalyst may be removed and the alcohol produced as a by-product or excess water may be removed by a method such as pressure reduction. Further, the hydrolysis product can be easily added to the subsequent condensation reaction by diluting the reaction mixture with a solvent used in the condensation reaction after the removal.

In the condensation reaction, raw water is by-produced between the silanol groups, and a by-product is produced between the silanol groups and the alkoxy groupsAlcohol is generated, thereby forming a siloxane bond. Any basic catalyst known in the art that can function as a dehydration condensation catalyst can be used in the condensation reaction. Among them, a substance having high basicity is preferable, and specific examples thereof include: sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca (OH) ₂ ) Isobasic salts, 1,8-diazabicyclo [5.4.0]Undec-7-ene, 1,5-diazabicyclo [4.3.0]Organic amines such as non-5-ene, and ammonium hydroxides such as tetramethylammonium hydroxide and tetrabutylammonium hydroxide. The exemplified compounds may be used either singly or in appropriate combination. Among the above exemplified compounds, tetramethylammonium hydroxide is particularly preferable because it has high catalytic activity and is easily available. In addition, when these basic catalysts are used as an aqueous solution, since the hydrolysis reaction proceeds also in the step of the condensation reaction, it is necessary to appropriately adjust the amount of water used in the hydrolysis by reducing the amount of water contained in the basic catalysts in advance.

The amount of the basic catalyst added is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, based on 100 parts by mass of the total of the component (a 1) and the component (a 2). When the amount of the additive exceeds 5 parts by mass, the orientation is as follows: the cured product produced using the obtained component (a) is easily colored, cannot be completely removed when the catalyst is removed, or the process of removing the catalyst becomes long. On the other hand, when the amount is less than 0.01 part by mass, the reaction tends to be substantially not progressed or the reaction time tends to be long.

The reaction temperature can be arbitrarily set depending on the reactivity of the component (a 1) or the component (a 2). The reaction temperature is usually 40 ℃ to 150 ℃ inclusive, preferably 60 ℃ to 100 ℃ inclusive. The condensation reaction is carried out in the presence of a polar solvent. When the reaction is carried out in a nonpolar solvent, the silanol group is not completely consumed, or the system is gelled due to an abnormal high molecular weight, which is not preferable. The polar solvent is preferably a polar solvent having compatibility with water, and particularly preferably a glycol ether. Among glycol ethers, dialkyl glycol ether solvents are particularly preferable because the above-mentioned abnormal increase in molecular weight is particularly unlikely to occur. Examples of the dialkyl glycol ether solvent that exhibits compatibility with water include: ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and the like.

The condensation reaction is carried out by setting the reaction temperature and sequentially adding a solution containing a hydrolysate obtained in the hydrolysis reaction to the polar solvent to which the dehydration condensation catalyst is added. The method of addition may be appropriately selected from known various methods. The time required for the addition may be arbitrarily set depending on the reactivity of each of the component (a 1) and the component (a 2), but is usually about 30 minutes to 12 hours.

The condensation reaction is preferably performed by dilution with a solvent so that the concentration of the component (a 1) (both in the case of the component (a 2) used in combination) in the reaction solution is preferably about 2% by mass or more and 80% by mass or less, and more preferably is performed by dilution with a solvent so that the concentration is about 15% by mass or more and 60% by mass or less. When a solvent having a boiling point higher than the boiling points of water and alcohol produced by the condensation reaction is used, these can be distilled off from the reaction system, and therefore, it is preferable. When the concentration is less than 2 mass%, the content of the component (a) contained in the negative radiation-sensitive resin composition to be obtained tends to be small. When the concentration exceeds 80% by mass, gelation may occur during the reaction, or the molecular weight of the component (a) to be produced tends to become too large.

After the condensation reaction is completed, when the catalyst used is removed, the stability of the component (a) or the negative radiation-sensitive resin composition containing the component (a) is improved, which is preferable. The method for removing the catalyst may be appropriately selected from known various methods depending on the catalyst used. For example, in the case of using tetramethylammonium hydroxide, after the condensation reaction is completed, it can be removed by a method such as adsorption or removal using a cation exchange resin.

(A) The components may be used singly or in combination.

(B) Multifunctional methacrylate

(B) The carbon-carbon double bond of the component (a) reacts with a thiol group of the component (a) (ene-thiol reaction), but the reaction mechanism differs depending on the kind of the carbon-carbon double bond or the presence or absence of a radical polymerization initiator.

In the present embodiment, a compound having two or more methacrylate groups in one molecule can be preferably used from the viewpoint of improving the storage stability of the negative radiation-sensitive resin composition or controlling the hardening properties of the insulating film obtained.

Specific examples of such a polyfunctional methacrylate include polyfunctional methacrylates such as difunctional methacrylates and trifunctional or higher-functional methacrylates.

Examples of difunctional methacrylates include: ethylene glycol dimethacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, and the like.

Examples of the trifunctional or higher methacrylate ester include: trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol pentamethylacrylate, ditrimethylolpropane tetramethacrylate, a mixture of dipentaerythritol pentamethylacrylate and dipentaerythritol hexamethacrylate, ethylene oxide-modified dipentaerythritol hexamethacrylate, tris (2-methacryloyloxyethyl) phosphate, succinic acid-modified dipentaerythritol pentamethylacrylate, and the like. Examples of the compound include a polyfunctional urethane methacrylate compound obtained by reacting a compound having a linear alkylene group and an alicyclic structure and having two or more isocyanate groups with a compound having one or more hydroxyl groups in the molecule and having three, four, or five methacryloxy groups. Among them, in terms of improving storage stability and curability of the insulating film obtained, the tetrafunctional or higher methacrylate is preferably pentaerythritol tetramethacrylate, trimethylolpropane trimethacrylate, or di-trimethylolpropane tetramethacrylate, and more preferably pentaerythritol tetramethacrylate or di-trimethylolpropane tetramethacrylate.

Regarding the content ratio of the component (B), the mass ratio of the component (B) to the component (a) is preferably 1/2 or more and 2/1 or less. Particularly preferably, the component (B) is a tetrafunctional or higher methacrylate ester, and the mass ratio of the component (B) to the component (A) is 1/2 or more and 2/1 or less. In these cases, the lower limit of the content of the component (B) is, specifically, preferably 20 parts by mass, and more preferably 50 parts by mass, based on 100 parts by mass of the component (a). On the other hand, the upper limit of the content of the component (B) is preferably 200 parts by mass, and more preferably 150 parts by mass, based on 100 parts by mass of the component (a). When the content ratio of the component (B) to the component (a) is within the above range, the properties and the like of the obtained insulating film can be more effectively improved.

(B) The components may be used singly or in combination.

(C) Photopolymerization initiator

(C) The component (A) is a compound which can generate free radicals by inducing radiation to initiate polymerization, namely a photo-free radical polymerization initiator.

Specific examples of the photopolymerization initiator (C) include: o-acyloxime compounds, α -aminoketone compounds, α -hydroxyketone compounds, acylphosphine oxide compounds, and the like.

Examples of the O-acyloxime compound include: 1- [ 9-ethyl-6- (2-methylbenzoyl) -9.H ] -carbazol-3-yl ] -ethane-1-ketoxime-O-acetate, 1- [ 9-ethyl-6-benzoyl-9.H ] -carbazol-3-yl ] -octane-1-ketoxime-O-acetate, 1- [ 9-ethyl-6- (2-methylbenzoyl) -9.H ] -carbazol-3-yl ] -ethane-1-ketoxime-O-benzoate, 1- [ 9-n-butyl-6- (2-ethylbenzoyl) -9.H ] -carbazol-3-yl ] -ethane-1-ketoxime-O-benzoate, ethanone, 1- [ 9-ethyl-6- (2-methyl-4-tetrahydrofurylbenzoyl) -9.H-carbazol-3-yl ] -,1- (O-acetyloxime), ethanone, 1- [ 9-ethyl-6- (2-methyl-4-tetrahydropyranylbenzoyl) -9.H-carbazol-3-yl ] -,1- (O-acetyloxime), ethanone, 1- [ 9-ethyl-6- (2-methyl-5-tetrahydrofurylbenzoyl) -9.H-carbazol-3-yl ] -,1- (O-acetyloxime), ethanone, 1- [ 9-ethyl-6- { 2-methyl-4- (2,2-dimethyl-1,3-dioxolanyl) methoxybenzoyl } -9.H-carbazol-3-yl ] -,1- (O-acetyloxime), ethanone, 1- [ 9-ethyl-6- (2-methyl-4-tetrahydrofuranylmethoxybenzoyl) -9.H-carbazol-3-yl ] -,1- (O-acetyloxime), 1,2-octanedione, 1- [4- (phenylthio) -,2- (O-benzoyloxime) ], and the like.

Examples of the α -aminoketone compound include: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2- (dimethylamino) -1- (4-morpholinophenyl) -2-benzyl-1-butanone, 1- [4- (2-hydroxyethylmercapto) phenyl ] -2-methyl-2- (4-morpholino) propan-1-one, and the like.

Examples of the α -hydroxyketone compound include: 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) one, 1-hydroxycyclohexyl phenyl ketone, and the like.

Examples of the acylphosphine oxide compound include: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide, and the like.

The photopolymerization initiator (C) is preferably an O-acyloxime compound, an α -aminoketone compound, and an acylphosphine oxide compound, more preferably an O-acyloxime compound and an α -aminoketone compound, and even more preferably an O-acyloxime compound, from the viewpoint of further promoting the curing reaction by radiation.

The oxime-based photopolymerization initiator such as an O-acyloxime compound generates a radical such as a phenyl radical or a methyl radical by light irradiation, and preferably performs polymerization by utilizing the radical. Among such oxime-based photopolymerization initiators, oxime-based photopolymerization initiators that generate a methyl radical are preferable in terms of high initiation efficiency of the polymerization reaction. In addition, from the viewpoint of more efficiently carrying out the polymerization reaction, it is preferable to use a photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350nm or more. Examples of the oxime ester polymerization initiator that generates such a methyl radical include compounds having a structure represented by the following formula (1).

[ solution 1]

In the formula (1), a represents a bonding site with another moiety in the compound.

The use of an oxime ester photopolymerization initiator which generates a methyl radical is preferable in terms of excellent curing properties, development resistance, an effect of suppressing the occurrence of defects in a pattern, and excellent physical properties of a cured film even under low-temperature curing conditions.

Examples of oxime ester photopolymerization initiators that generate an alkyl radical containing a methyl radical include: ethanone, 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -,1- (o-acetyl oxime) (trade name: brilliant (Irgacure) OXE-02, manufactured by BASF), [8- [ [ (acetoxy) imino ] [2- (2,2,3,3-tetrafluoropropoxy) phenyl ] methyl ] -11- (2-ethylhexyl) -11H-benzo [ a ] carbazol-5-yl ] -, (3536 zxft 36-trimethylphenyl) (trade name: brilliant (Irgacure) OXE-03, manufactured by BASF), ethanone, 1- [ 9-ethyl-6- (1,3-dioxolane, 4- (2-methoxyphenoxy) -9H-carbazol-3-yl ] -,1- (o-acetyl oxime) (trade name Ai Dike (ADEKEKEK A) OPT-N-1919, 4- (2-methoxyphenoxy) -9H-carbazol-3-yl ] -, manufactured by 3534- (ADxzethoxy) -2-acetyl oxime) (trade name: acetyl-3528, manufactured by ADEK-3-34, manufactured by NCxzft 3534, 1-propanone, 3-cyclopentyl-1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -,1- (o-acetyloxime) (trade name TR-PBG-304, manufactured by chanzhou strong electron new material corporation), 1-propanone, 3-cyclopentyl-1- [2- (2-pyrimidinylthio) -9H-carbazol-3-yl ] -,1- (o-acetyloxime) (trade name TR-PBG-314, manufactured by chanzhou strong electron new material corporation), ethanone, 2-cyclohexyl-1- [2- (2-pyrimidinyloxy) -9H-carbazol-3-yl ] -,1- (o-acetyloxime) (trade name TR-PBG-326, manufactured by chanzhou strong electron new material corporation), ethanone, 2-cyclohexyl-1- [2- (2-pyrimidinylthio) -9H-carbazol-3-yl ] -,1- (o-acetyloxime) (trade name TR-PBG-331, manufactured by chanzhou strong electron new material corporation), 1-octanone, 1- [4- [3- [ (acetyloxy) imino ] ethyl ] -9H-carbazol-3-yl ] -894-phenyl ] -78H-phenyl- ] -phenyl-fts, manufactured by chan strong electron new material corporation, 1-octanone, 1- [4- [ 3-ethyl ] -894- [ 2-pyrimidinyloxy ] -894-yl ] -892-phenyl ] -78 -,1- (o-acetyloxime) (trade name: EXTA-9, manufactured by Union Chemicals), etc.

In addition, a photopolymerization initiator having a tertiary amine structure may be used in combination with the oxime ester photopolymerization initiator. This is because the photopolymerization initiator having a tertiary amine structure has a tertiary amine structure as an oxygen quencher in a molecule, and thus radicals generated from the initiator are less likely to be deactivated by oxygen, and sensitivity can be improved. Examples of commercially available products of the photopolymerization initiator having a tertiary amine structure include: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (e.g., brilliant (Irgacure) 907, manufactured by BASF corporation), 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone (e.g., brilliant (Irgacure) 369, manufactured by BASF corporation), 4,4' -bis (diethylamino) benzophenone (e.g., heloud (high-cure) ABP, manufactured by Chuanyu medicine), and the like.

As described above, the component (C) may be used alone or in combination of two or more. The content ratio of the component (C) is preferably 1 part by mass or more and 40 parts by mass or less, and more preferably 5 parts by mass or more and 30 parts by mass or less, with respect to 100 parts by mass of the component (a). By setting the content ratio to 1 part by mass or more and 40 parts by mass or less, a cured film having high solvent resistance, high hardness, and high adhesion can be formed even when the negative radiation-sensitive resin composition is exposed to a low amount of light. As a result, an insulating film having more excellent characteristics can be provided.

(F) Organic solvent

The negative radiation-sensitive resin composition may further contain (F) an organic solvent. The organic solvent (F) is not particularly limited, and examples thereof include: alcohol-based solvents, ether-based solvents, ester-based solvents, ketone-based solvents, amide-based solvents, and the like. (F) The organic solvent may be used alone or in combination of two or more.

Examples of the alcohol solvent include: alkyl alcohols such as methanol, ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-hexanol, 1-octanol, 1-nonanol, 1-dodecanol, 1-methoxy-2-propanol, and diacetone alcohol; aromatic alcohols such as benzyl alcohol, and the like.

Examples of the ether solvent include: ethylene glycol monoalkyl ethers such as diethylene glycol methyl ethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether; diethylene glycol monoalkyl ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol ethyl methyl ether; and dipropylene glycol monoalkyl ethers such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, and dipropylene glycol monobutyl ether.

Examples of the ester-based solvent include: carboxylic acid esters such as ethyl acetate, isopropyl acetate, n-butyl acetate, amyl acetate, ethyl lactate, methyl 3-methoxypropionate, and ethyl 3-ethoxypropionate; polyhydric alcohol carboxylate solvents such as propylene glycol diacetate; and polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate.

Examples of the ketone solvent include: acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl amyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, and the like.

Among these, ether solvents and ester solvents are preferable, ester solvents are more preferable, and polyol partial ether carboxylate solvents are even more preferable. Among the ether solvents and ester solvents, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, and methyl 3-methoxypropionate are preferable.

The content of the (F) organic solvent in the negative radiation-sensitive resin composition is not particularly limited, but is preferably prepared so that the concentration of the solid component (components other than the (F) organic solvent) is in the range below. The lower limit of the solid content concentration in the negative radiation-sensitive resin composition is preferably 5 mass%, more preferably 10 mass%, and still more preferably 20 mass%. On the other hand, the upper limit of the solid content concentration is preferably 60% by mass, more preferably 50% by mass, and still more preferably 40% by mass.

(D) Ultraviolet absorber

The negative radiation-sensitive resin composition may further contain (D) an ultraviolet absorber (hereinafter, also referred to as a "(D) component"). (D) The component (D) is added for the purpose of controlling the light hardening distribution by absorbing a specific wavelength of a light source for exposure. When the negative radiation-sensitive resin composition contains the component (D), the following effects tend to be obtained: improve the taper shape after development, and reduce the residue left in the unexposed part after development. As the component (D), a compound having a maximum absorption at a wavelength of 250nm to 400nm, for example, can be used from the viewpoint of inhibiting light absorption by the component (C).

Examples of the component (D) include: benzotriazole-based compounds, triazine-based compounds, benzophenone compounds, benzoate compounds, cinnamic acid derivatives, naphthalene derivatives, anthracene and its derivatives, dinaphthalene compounds, phenanthroline compounds, dyes, and the like.

(D) The components may be used alone or in combination of two or more.

Of these, from the viewpoint of increasing the taper angle, benzotriazole compounds and/or hydroxyphenyltriazine compounds are preferable, and benzotriazole compounds are particularly preferable. Specifically, examples of the benzotriazole compound include 2- (5-tert-butyl-2-hydroxyphenyl) benzotriazole, 2,2-methylenebis {6- (benzotriazol-2-yl-4-tert-octylphenol) } and the like. Examples of the benzophenone-based organic compound include 2,2-di-hydroxy-4,4-dimethoxybenzophenone and the like. Examples of the triazine-based organic compound include 2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine. Examples of commercially available products that can be obtained include: "Dennu (TINUVIN) PS", "Dennu (TINUVIN) P", "Dennu (TINUVIN) 324", "Dennu (TINUVIN) 326", "Dennu (TINUVIN) 360", "Siesbeck (Seesorb) 107" manufactured by Shipro Kasei corporation, "Adekatb (Adekastab) LA-F70" manufactured by Ai Dike (ADEKA) and the like.

The content ratio of the component (D) is preferably 0.1 part by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 30 parts by mass or less, further preferably 10 parts by mass or more and 30 parts by mass or less, and further preferably 20 parts by mass or more and 30 parts by mass or less, with respect to 100 parts by mass of the component (a). By satisfying the range by the content ratio, the shape and resolution of the obtained pattern are improved.

(E) Alkali generating agent

The negative radiation-sensitive resin composition may further contain (E) a base generator (hereinafter, also referred to as "(E) component").

The base generator (E) is not particularly limited as long as it is a compound that generates a base (such as an amine) by irradiation with radiation. Examples of (E) the base generator include: transition metal complexes such as cobalt, o-nitrobenzyl carbamates, α -dimethyl-3,5-dimethoxybenzyl carbamates, acyloxyimino compounds, and the like.

Examples of the transition metal complex include: bromine penta-amino cobalt perchlorate, bromine pentamethyl amine cobalt perchlorate, bromine penta-propylamine cobalt perchlorate, hexa-amino cobalt perchlorate, hexamethyl amine cobalt perchlorate, hexa-propylamine cobalt perchlorate, etc.

Examples of the ortho-nitrobenzyl carbamates include: [ [ (2-nitrobenzyl) oxy ] carbonyl ] methylamine, [ [ (2-nitrobenzyl) oxy ] carbonyl ] propylamine, [ [ (2-nitrobenzyl) oxy ] carbonyl ] hexylamine, [ [ (2-nitrobenzyl) oxy ] carbonyl ] cyclohexylamine, and the like.

Examples of the α, α -dimethyl-3,5-dimethoxybenzyl carbamates include [ [ (α, α -dimethyl-3,5-dimethoxybenzyl) oxy ] carbonyl ] methylamine and [ [ (α, α -dimethyl-3,5-dimethoxybenzyl) oxy ] carbonyl ] propylamine.

Examples of the acyloxyimino group include: propionyl acetophenone oxime, propionyl benzophenone oxime, propionyl acetone oxime, butyryl acetophenone oxime, butyryl benzophenone oxime, butyryl acetone oxime, adipoyl acetophenone oxime, adipoyl benzophenone oxime, and the like.

Examples of the other alkali generators than the above include: 2-nitrobenzyl cyclohexyl carbamate, O-carbamoyl hydroxyamide and O-carbamoyl hydroxyamide 1,2-diisopropyl-3- { bis (dimethylamino) methylene } guanidinium =2- (3-benzoylphenyl) propionate.

(E) The alkali generating agent may be used alone or in combination of two or more.

The lower limit of the content ratio of the alkali generating agent (E) is preferably 0.1 part by mass, more preferably 1 part by mass, per 100 parts by mass of the component (a). The upper limit of the content of the alkali generating agent (E) is preferably 20 parts by mass, and more preferably 10 parts by mass, based on 100 parts by mass of the component (a). By the content ratio satisfying the range, the obtained pattern shape and heat resistance become good at a high level.

(other Components)

The negative radiation-sensitive resin composition may further contain the component (a), the component (B), the component (C), the component (D), the component (E), and the component (F) other than the organic solvent. Examples of such other components include: a curing agent, a curing accelerator, a sealing aid, an antioxidant, a surfactant, and the like. However, the content of the other components other than the component (a), the component (B), the component (C), the component (D), the component (E), and the organic solvent (F) in the negative radiation-sensitive resin composition is preferably 10 mass% or less in some cases, and more preferably 1 mass% or less in some cases.

(viscosity of negative radiation-sensitive resin composition)

The viscosity of the negative radiation-sensitive resin composition measured at 25 ℃ and 50rpm using an E-type viscometer is preferably 0.5 to 20mPa · s, more preferably 0.5 to 7mPa · s, and still more preferably 2.5 to 5mPa · s. When the viscosity satisfies the above range, the resolution, the residual film ratio, the chemical resistance, the oxidation and ashing resistance, and the storage stability, which will be described later, are all excellent. The viscosity of the negative radiation-sensitive resin composition can be set to the above range by adjusting the amount of the added (F) organic solvent.

< temperature for forming hardened film >

As described above, the negative radiation-sensitive resin composition can provide a cured film having sufficient etching resistance and oxidation and ashing resistance even when heated at a relatively low temperature. The negative radiation-sensitive resin composition is preferably a composition that can be cured by heating at a temperature in the range of, for example, 60 ℃ to 120 ℃, and more preferably a composition that can be cured by heating at a temperature in the range of 60 ℃ to 100 ℃.

< preparation of negative radiation-sensitive resin composition >

The negative radiation-sensitive resin composition can be prepared by mixing the respective components at a predetermined ratio and dissolving the mixture in (F) an organic solvent. The composition thus prepared is preferably filtered through a filter having a pore size of about 0.2. Mu.m, for example.

< insulating film for organic EL element >

The insulating film for an organic EL element according to an embodiment of the present invention is a cured film formed from the negative radiation-sensitive resin composition. The insulating film for an organic EL element may be a patterned film. The insulating film for an organic EL element is formed from a negative radiation-sensitive resin composition which can provide a cured film having sufficient etching resistance and ashing resistance even when heated at a relatively low temperature, and therefore has a high yield and excellent durability.

The insulating film for an organic EL element is suitable as an interlayer insulating film, and can be used for a planarization film, a spacer, a protective film, and the like. The insulating film for an organic EL element can also be used for display devices including organic EL elements (organic EL devices), electronic paper, and the like. As will be described later, the insulating film for an organic EL element is suitable as an interlayer insulating film between a touch panel and another layer in a display device including a touch panel such as an organic EL device including a touch panel.

The insulating film for organic EL element is less likely to crack even when it is relatively thick. Therefore, the insulating film for a display device can be formed thick. The lower limit of the average thickness of the insulating film for organic EL element may be, for example, 0.1 μm, and may be 0.5 μm, more preferably 1 μm, and still more preferably 2 μm. On the other hand, the upper limit of the average thickness is, for example, 10 μm, and may be 6 μm or 4 μm.

The insulating film for organic EL elements can be provided on various display devices. Such a display device includes an organic EL device, electronic paper, and the like, and among these, an organic EL device is preferable.

< organic EL device >

An organic EL device according to an embodiment of the present invention includes the insulating film for an organic EL element. The organic EL device preferably includes a touch panel laminated on a substrate having organic EL elements. An organic EL device generally has a laminated structure including an anode layer, an organic light-emitting layer, and a cathode layer. The insulating film for organic EL elements is preferably used for at least a part of the insulating film in the touch panel. In particular, it is preferable that the insulating film for an organic EL element is used for an insulating film of a touch panel which is laminated on a substrate having an organic EL element without an adhesive layer or an adhesive layer. By doing so, the touch panel can be directly laminated on the substrate on which the organic EL element is formed, and therefore, the organic EL device including the touch panel can be thinned.

The negative radiation-sensitive resin composition can provide a cured film having sufficient etching resistance and oxidation and ashing resistance even when heated at a relatively low temperature, and therefore can suppress deterioration of an organic EL element in a process for manufacturing the organic EL device, and can improve yield and the like. In addition, since the insulating film can be formed by heating at a relatively low temperature using the negative radiation-sensitive resin composition in this manner to suppress the deterioration of the organic EL element in the production process, the negative radiation-sensitive resin composition can be particularly preferably used in the formation of the insulating film in various organic EL devices including organic EL elements other than the organic EL device including a touch panel.

Fig. 1 shows an embodiment of an organic EL device including a touch panel. The organic EL device with a touch panel 10 of fig. 1 includes an organic EL display substrate 20 and a touch panel 30. The organic EL display substrate 20 has a structure in which a support substrate 21, an anode layer 22, an organic light-emitting layer 23, a cathode layer 24, an adhesive layer 25, and a sealing substrate 26 are sequentially stacked. At least the anode layer 22, the organic light-emitting layer 23, and the cathode layer 24 constitute an organic EL element. The organic light-emitting layer 23 may be, for example, a structure in which a hole injection layer, a hole transport layer, an organic EL light-emitting layer, an electron transport layer, and an electron injection layer are sequentially stacked from the anode layer 22 side.

The touch panel 30 is of a capacitance type in which a first sensor electrode 31, an insulating film 33, and a second sensor electrode 32 are sequentially stacked. The touch panel 30 includes a first sensor electrode 31, a second sensor electrode 32 disposed to face the first sensor electrode 31, an insulating film 33, and a transparent substrate 34 disposed on the outermost surface. In the present embodiment, the first sensor electrode 31 is formed directly on the sealing substrate 26 of the organic EL display substrate 20. The insulating film 33 is a transparent insulating film that insulates the first sensor electrode 31 and the second sensor electrode 32, and is formed of the negative radiation-sensitive resin composition. The touch panel is not limited to the capacitive touch panel.

< method for forming insulating film for organic EL element >

The method for forming an insulating film for an organic EL element according to one embodiment of the present invention includes: a step of forming a coating film by directly or indirectly applying the negative radiation-sensitive resin composition onto a substrate (hereinafter, also referred to as "coating film forming step"); a step of irradiating (exposing) at least a part of the coating film with radiation after the step of forming the coating film (hereinafter, also referred to as a "radiation irradiation step"); a step of developing the coating film after the step of irradiating the radiation (hereinafter, also referred to as "developing step"); and a step (hereinafter, also referred to as "heating step") of heating the coating film at a temperature of 60 ℃ or higher and 120 ℃ or lower after the step of developing. The forming method may include a step of heating the coating film between the radiation irradiation step and the development step (hereinafter, also referred to as a "Post Exposure Bake (PEB) step") as an arbitrary step.

According to the above-mentioned forming method, since the negative radiation-sensitive resin composition is used, it is possible to pattern the insulating film into a good shape and obtain an insulating film having sufficient etching resistance and ashing resistance even by heating at a relatively low temperature. Even when the substrate on which the coating film is formed includes an organic EL element, deterioration of the organic EL element can be suppressed by performing the heating step at a relatively low temperature. Hereinafter, each step will be explained.

(coating film formation step)

In this step, after the negative radiation-sensitive resin composition is applied directly or via another layer onto a substrate, the applied surface is preferably heated (prebaked) to remove the organic solvent and the like, thereby forming a coating film. Examples of the material of the substrate include: glass, quartz, silicon, resin, etc. Specific examples of the resin include: polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, polyimide, an addition polymer of a cyclic olefin, a ring-opening polymer of a cyclic olefin, a hydride thereof, and the like.

The substrate may include an organic EL element or the like. The substrate may be a substrate having an electrode, wiring, or the like provided on the coating surface. As such a substrate, the organic EL display substrate 20 in which the first sensor electrode 31 is formed in fig. 1 can be exemplified.

The method for applying the negative radiation-sensitive resin composition is not particularly limited, and for example, the following methods can be used: a spraying method, a roll coating method, a spin coating method (spin coat method), a slit die coating method, a bar coating method, and the like. Among these coating methods, spin coating and slit die coating are particularly preferable. The conditions for the prebaking may vary depending on the kind of each component, the blending ratio, and the like, and may be, for example, 60 ℃ to 120 ℃, more preferably 100 ℃ to 1 minute to 10 minutes.

(radiation irradiation step)

In this step, at least a part of the coating film formed in the coating film forming step is irradiated with radiation. In general, when a part of the coating film is irradiated with radiation, the part is irradiated through a photomask having a predetermined pattern. As the radiation, for example, visible light, ultraviolet light, far ultraviolet light, electron beam, X-ray, or the like can be used. Of these radiations, radiation having a wavelength in the range of 190nm to 450nm is preferable, and radiation including ultraviolet rays of 365nm is more preferable.

The lower limit of the exposure amount in this step is preferably a value obtained by measuring the intensity of radiation at a wavelength of 365nm with a luminometer ("OAI model 356" of OAI Optical Associates inc.) (OAI Optical Associates inc.) ² More preferably 50mJ/cm ² . The upper limit of the exposure amount is preferably 2,000mJ/cm in a value measured by the illuminometer ² More preferably 1,000mJ/cm ² 。

(PEB Process)

When the PEB step is provided, the PEB conditions may vary depending on the type of each component, the blending ratio, and the like, and may be, for example, a temperature of 60 ℃ to 120 ℃, more preferably 100 ℃ or less, and a heating time of 1 minute to 10 minutes.

(developing step)

In this step, the coating film after the irradiation with the radiation is developed with a developer to form a predetermined pattern. The developer is preferably an alkaline developer. Examples of the alkaline developing solution include an alkaline aqueous solution in which at least one of alkaline compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, tetramethylammonium hydroxide, and tetraethylammonium hydroxide is dissolved. In addition, an appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant may be added to the alkaline developer.

As the developing method, for example, a suitable method such as a liquid coating method, a dipping method, a shaking dipping method, a spraying method, or the like can be used. The developing time varies depending on the composition of the radiation-sensitive resin composition, and is, for example, 10 seconds to 180 seconds. After such a development treatment, for example, a water-flowing cleaning is performed for a treatment time of 30 seconds to 90 seconds, and then, for example, air-drying is performed by using compressed air or compressed nitrogen gas, whereby a desired pattern can be formed.

(heating step)

In this step, the coating film patterned by development is heated (post-baked) using a heating device such as a hot plate or an oven, thereby obtaining an insulating film for a display device having a desired pattern. Further, the coating film may be irradiated with radiation such as ultraviolet rays between the developing step and the heating step. The exposure amount at this time may be, for example, 100mJ/cm ² 2,000mJ/cm or more ² The following. The lower limit of the heating temperature is 60 ℃ and preferably 80 ℃. By setting the heating temperature to the lower limit or more, a sufficiently cured insulating film can be obtained. On the other hand, the upper limit of the heating temperature is 120 ℃ and preferably 100 ℃. By setting the heating temperature to the lower limit or more, for example, an insulating film which is sufficiently cured can be obtained while suppressing deterioration of an organic EL element included in a substrate. In addition, by setting the heating temperature to the upper limit or less, excessive stress generation such as rapid film shrinkage can be suppressed, and therefore, generation of cracks can be suppressed. In this manner, the heating step is performed at a temperature ranging from 60 ℃ to 120 ℃. The heating time varies depending on the type of heating equipment, and for example, in the case of heating on a hot plate, it may be set to 5 minutes or more and 30 minutes or less, and in the case of heating in an oven, it may be set to 10 minutes or more and 90 minutes or less. The heating may be performed in air, or may be performed in an inert gas atmosphere such as nitrogen or argon. In addition, a step baking method in which the heating step is performed twice or more can also be used.

(other steps)

In the case of manufacturing the organic EL device, after the insulating film for the organic EL element is formed on the organic EL display substrate, other steps for forming further electrodes, wirings, and the like (for example, the second sensor electrodes 32 in the touch panel 30 of fig. 1) and the like are performed. Examples of such a step include: an electrode forming step, a wiring forming step, an etching step, an ashing step, and the like. A known method such as printing or vapor deposition may be used for forming the electrodes or the wirings. The etching can be performed using a known etching chemical such as an amine-based solution. The ashing may be performed by a known ashing method such as oxygen ashing. In addition, in the production of a touch panel or the like, the formation of an insulating film, the formation of electrodes, wirings, and the like may be performed a plurality of times.

[ examples ]

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

< determination of weight average molecular weight (Mw) >)

In the following examples of synthesis of polymers, the weight average molecular weight (Mw) of the obtained polymer was measured by Gel Permeation Chromatography (GPC) under the following conditions.

The device comprises the following steps: "GPC-101" by Showa electrician corporation "

Pipe column: there are connected "GPC-KF-801", "GPC-KF-802", "GPC-KF-803" and "GPC-KF-804" of Showa Denko K.K.)

Mobile phase: tetrahydrofuran (THF)

Temperature of the pipe column: 40 deg.C

Flow rate: 1.0mL/min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μ L

A detector: differential refractometer

Standard substance: monodisperse polystyrene

< measurement of viscosity >

The viscosity is measured in accordance with Japanese Industrial Standards (JIS) K2283:2000, a value measured at 25 ℃ using an E-type viscometer ("TVE 22L" manufactured by Toyobo industries Co., ltd.).

An example of synthesizing the thiol group-containing polysiloxane as the component (a) is shown below. In the following description, "%" means "% by mass" unless otherwise specified.

Synthesis example 1 preparation of thiol group-containing polysiloxane solution (A-1)

190g of 3-mercaptopropyltrimethoxysilane (trade name "KBM-803" manufactured by shin-Etsu chemical industry, ltd.) as the component (a 1), 52.3g of ion exchange water ([ mole number of water used in hydrolysis ]/[ mole number of alkoxy groups contained in the component (a 1) ] (mole ratio) = 1.0), and 9.5g of 95% formic acid were charged into a reaction apparatus including a stirrer, a cooling tube, a water separator, a thermometer, and a nitrogen gas blowing port, and hydrolysis reaction was performed at room temperature for 30 minutes. During the reaction, the temperature rose by a maximum of 22 ℃ due to heat generation. After the reaction, propylene glycol monomethyl ether acetate 287.36g was charged and heated. After the temperature was raised to 82 ℃, methanol produced by hydrolysis began to be distilled off. It took a further 30 minutes to heat up to 105 ℃ and distill off the water produced by the condensation reaction. After further reaction at 105 ℃ for 1 hour and 30 minutes, a part of the remaining methanol, water, formic acid and propylene glycol monomethyl ether acetate was distilled off under reduced pressure of 70 to 150mmHg to obtain 385.2g of a condensate solution (A-1). The "total mole number of unreacted hydroxyl groups and unreacted alkoxy groups ]/[ mole number of alkoxy groups contained in the component (a 1)" (molar ratio) in the thiol group-containing polysiloxane contained in the condensate solution (a-1) was 0.15, and the concentration was 32.0%. The condensate solution (A-1) had a mercaptan equivalent weight of 398g/eq and Mw of 2147.

Synthesis example 2 preparation of thiol group-containing polysiloxane solution (A-2)

Into a reaction apparatus equipped with a stirrer, a cooling tube, a water separator, a thermometer, a dropping funnel, and a nitrogen gas inlet, 300g of 3-mercaptopropyltrimethoxysilane (product name "KBM-803" manufactured by shin-Etsu chemical industries, ltd.) as the component (a 1), 162.8g of ion exchange water ([ mole number of water used in hydrolysis ]/[ mole number of alkoxy groups contained in the component (a 1] (molar ratio) = 2.0), and 6.0g of a cation exchange resin (product name "Daaion) PK228LH" manufactured by Mitsubishi chemical industries, H type strongly acidic cation exchange resin) were charged, and hydrolysis reaction was carried out at room temperature for 30 minutes. During the reaction, the temperature rose by a maximum of 28 ℃ due to heat generation. After the reaction, the cation exchange resin was separated by filtration, and the pressure was reduced at 70 ℃ and 20kPa for 3 hours, whereby 228g of a hydrolysate was obtained. This was diluted with 82g of ethylene glycol dimethyl ether to obtain 310g of a hydrolysate solution.

Then, 325.9g of ethylene glycol dimethyl ether and 1.25g of a 25% aqueous solution of tetramethylammonium hydroxide were put into another reaction vessel and heated to 80 ℃. Tetramethylammonium hydroxide was insoluble in ethylene glycol dimethyl ether and became slightly turbid. 300g of the obtained hydrolysate solution was added dropwise thereto over 2 hours and 30 minutes. During the dropwise addition, the tetramethylammonium hydroxide was dissolved, and the reaction solution became clear (clear). After dropwise addition, the reaction mixture was further reacted at 80 ℃ for 15 minutes, and then cooled to 25 ℃. At 25 ℃ tetramethylammonium hydroxide did not dissolve and the reaction solution became slightly turbid. 6.4g of the same cation exchange resin as described above was charged therein, and stirred at room temperature for 4 hours. During the stirring process, the tetramethylammonium hydroxide is absorbed by the cation exchange resin, and the reaction solution becomes clear. After the cation exchange resin was separated by filtration, the pressure was reduced at 70 ℃ and 20kPa for 2 hours, and further at 70 ℃ and 0.7kPa for 1 hour, whereby 196g of the thiol group-containing polysiloxane solution (A-2) was obtained. When the thiol group-containing polysiloxane ((A-2) component) contained in the solution (A-2) was analyzed by infrared spectroscopy, 3500cm ^-1 The absorption of nearby visible silanol groups is completely absent. Further, no silanol group was found by the analysis by nuclear magnetic resonance. The total mole number of [ unreacted hydroxyl groups and unreacted alkoxy groups ] in the component (A-2)]/[ moles of alkoxy groups contained in component (a 1) ]](molar ratio) is 0. The concentration of component (A-2) in solution (A-2) was 94.7%, the mercaptan equivalent weight was 133g/eq, and the Mw was 2700.

[ preparation of negative radiation-sensitive resin composition ]

The raw materials used in the preparation of each negative radiation-sensitive resin composition are shown below.

(A) Composition (I)

A-1: thiol group-containing polysiloxane obtained in Synthesis example 1

A-2: the thiol group-containing polysiloxane obtained in Synthesis example 2

A-3: thiol group-containing polysiloxane (Kang Pala Sen (Compacran) SQ109 manufactured by Ishikawa chemical industries, ltd.)

(a) Comparative Components

a-1: pentaerythritol tetrakis (3-mercaptopropionate) (pentaerythritoltetra (3-mercaptopropionate), PEMP)

(B) Composition (I)

B-1: pentaerythritol Tetramethylacrylate

B-2: di-trimethylolpropane tetra methyl acrylate

B-3: trimethylolpropane trimethacrylate

(b) Comparative Components

b-1: dipentaerythritol hexaacrylate (DPHA)

(C) Composition (A)

C-1:1,2-octanedione, 1- {4- (phenylthio) phenyl } -,2- (O-benzoyl oxime) (IRGACURE OXE-01, manufactured by BASF corporation)

C-2: NCI-930 (Ai Dike (ADEKA) Co., ltd.)

C-3: 2-methyl-1- {4- (methylthio) phenyl } -2-morpholinopropan-1-one (IRGACURE) 907 manufactured by BASF corporation)

(D) Composition (A)

D-1: dennubin (Tinuvin) PS (manufactured by BASF corporation)

D-2: dennubin (Tinuvin) 324 (manufactured by BASF corporation)

(E) Composition (I)

E-1:1,2-diisopropyl-3- { bis (dimethylamino) methylene } guanidinium =2- (3-benzoylphenyl) propionate

(F) Organic solvent

F-1: propylene Glycol Monomethyl Ether Acetate (PGMEA)

Examples of the preparation of the negative radiation-sensitive resin composition are shown below. In the following description, "%" means "% by mass" unless otherwise specified.

(example 1)

The negative radiation-sensitive resin composition of example 1 was prepared by dissolving 100 parts by mass of (a-1) as the (a) component, 200 parts by mass of (B-1) as the (B) component, 15 parts by mass of (C-1) as the (C) component, and 20 parts by mass of (D-2) as the (D) component in the solution (a-1) obtained in synthesis example 1 in 500 parts by mass of (F-1) as the (F) organic solvent. The negative radiation-sensitive resin composition thus obtained had a viscosity of 3.5 mPas as measured at 25 ℃ and 50rpm using an E-type viscometer. The results are shown in Table 1.

(examples 2 to 11, comparative examples 1 to 2)

Negative radiation-sensitive resin compositions of examples 2 to 11 and comparative examples 1 to 2 were prepared in the same manner as in example 1, except that the respective components were used in the kinds and contents shown in table 1, and the viscosity of the obtained negative radiation-sensitive resin compositions was measured in the same manner as in example 1. The results are shown in Table 1.

[ evaluation ]

The obtained negative radiation-sensitive resin composition was evaluated for resolution, residual film ratio, chemical resistance, oxidation and ashing resistance, and storage stability by the following methods. The results are shown in Table 1.

< resolution >

After the negative radiation-sensitive resin composition was applied onto a silicon substrate by spin coating, it was prebaked on a hot plate at 85 ℃ for 2 minutes, thereby forming a coating film having a thickness of 2.5 μm. A high-pressure mercury lamp (exposure at 365 nm: 100 mJ/cm) was used for the obtained coating film ² ) After exposure through a mask having a square blank pattern with one side of 10 μm arranged at 10 μm intervals, development was performed for 60 seconds at 25 ℃ by a liquid coating method using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide. Then, the silicon substrate was cleaned with ultrapure water for 60 seconds Zhong Liushui and dried, thereby forming a pattern on the silicon substrate. Manufactured using a scanning electron microscope (Hitachi, ltd. (Strand Co.))S-4200) of (a) was observed at a magnification of 1500 times the sectional shape of the square blank pattern having one side of 10 μm obtained in the above manner. The one having no residual pattern opening was evaluated as good and indicated as "a", and the one having residual pattern opening was evaluated as bad and indicated as "B".

< residual film ratio >

After the negative radiation-sensitive resin composition was applied onto a silicon substrate by spin coating, it was prebaked on a hot plate at 85 ℃ for 2 minutes, thereby forming a coating film having a thickness of 2.5 μm. A high-pressure mercury lamp (exposure at 365 nm: 100 mJ/cm) was used for the obtained coating film ² ) After the entire surface was exposed, development was carried out by a liquid coating method at 25 ℃ for 60 seconds using a 2.38 mass% aqueous tetramethylammonium hydroxide solution. Then, the silicon substrate was cleaned with ultrapure water for 60 seconds Zhong Liushui and dried to form a film thereon. The average film thickness before and after development was measured, and the residual film ratio (residual film ratio before and after development) was calculated based on the following formula (1). The residual film rate was evaluated according to the following criteria. That is, when the residual film ratio is 85% or more, the evaluation is extremely good and is represented by "a", when the residual film ratio is 80% or more and less than 85%, the evaluation is very good and is represented by "B", when the residual film ratio is 75% or more and less than 80%, the evaluation is good and is represented by "C", and when the residual film ratio is less than 75%, the evaluation is bad and is represented by "D".

Residual film ratio (%) = { (average film thickness after development)/(average film thickness before development) } × 100 · · (equation 1)

Chemical resistance >

After the negative radiation-sensitive resin composition was applied onto a silicon substrate by spin coating, it was prebaked on a hot plate at 85 ℃ for 2 minutes, thereby forming a coating film having a thickness of 2.5 μm. A high-pressure mercury lamp (exposure at 365 nm: 100 mJ/cm) was used for the obtained coating film ² ) After the entire surface was exposed to light, the resultant was developed by a liquid coating method at 25 ℃ for 60 seconds using a 2.38 mass% aqueous tetramethylammonium hydroxide solution. Then, the silicon substrate was washed with ultrapure water for 60 seconds Zhong Liushui and dried, thereby forming a film on the silicon substrate. Then is connected toUsing a high pressure mercury lamp (exposure at 365nm of 200 mJ/cm) ² ) After exposure of the entire surface, post-baking was performed in an oven at 85 ℃ for 1 hour. The obtained substrate was immersed in a 70 mass% aqueous solution of 2-aminoethanol at 60 ℃ for 5 minutes. The average film thickness before and after immersion was measured, and the ratio of the average film thickness after immersion to the average film thickness before immersion (film thickness ratio before and after immersion) was calculated. The ratio was evaluated according to the following criteria. That is, when the film thickness ratio before and after the dipping is 97% or more and less than 103%, the evaluation is extremely good and is expressed as "a", when the film thickness ratio before and after the dipping is 95% or more and less than 97%, the evaluation is very good and is expressed as "B", when the film thickness ratio before and after the dipping is 103% or more and less than 105%, the evaluation is good and is expressed as "C", and when the film thickness ratio before and after the dipping is less than 95% or less than 105%, the evaluation is poor due to the peeling of the cured film and is expressed as "D".

< Oxidation and Ash resistance >

After the negative radiation-sensitive resin composition was applied onto a silicon substrate by spin coating, it was prebaked on a hot plate at 85 ℃ for 2 minutes, thereby forming a coating film having a thickness of 2.5 μm. A high-pressure mercury lamp (exposure at 365 nm: 100 mJ/cm) was used for the obtained coating film ² ) After the entire surface was exposed, development was carried out by a liquid coating method at 25 ℃ for 60 seconds using a 2.38 mass% aqueous tetramethylammonium hydroxide solution. Then, the silicon substrate was washed with ultrapure water for 60 seconds Zhong Liushui and dried, thereby forming a film on the silicon substrate. Then, a high-pressure mercury lamp (exposure at 365 nm: 100 mJ/cm) was used ² ) After exposure of the entire surface, post-baking was performed in an oven at 85 ℃ for 1 hour. The film (cured film) formed on the substrate in the above manner was subjected to predetermined conditions (300W, 30sec, O) ₂ 30 sccm) was performed. The average film thickness before and after ashing was measured, and the residual film ratio (residual film ratio before and after ashing) was calculated based on the following equation (2). The oxidation and ashing resistance was evaluated by the following criteria using the calculated residual film ratio. That is, when the residual film ratio is 95% or more, the evaluation is extremely good and is represented by "a", and when the residual film ratio is 93% or more and less than 95%, the evaluation is extremely goodThe evaluation was very good and indicated as "B", when the residual film ratio was 90% or more and less than 93%, the evaluation was good and indicated as "C", and when the residual film ratio was less than 90%, the evaluation was bad and indicated as "D".

Residual film ratio (%) = { (average film thickness after ashing)/(average film thickness before ashing) } × 100 · · (equation 2)

< storage stability >

After 10mL of the negative radiation-sensitive resin composition was placed in a threaded tube and stored at 40 ℃ in the shade for 3 days, the viscosity before and after storage was measured in the same manner as the above-mentioned viscosity measurement, and the viscosity increase rate before and after storage was confirmed by the following formula (3). When the viscosity increase rate was less than 110%, the evaluation was good and indicated as "a", and when the viscosity increase rate was 110% or more, the evaluation was bad and indicated as "B".

Viscosity increase rate (%) = { (viscosity after storage)/(viscosity before storage) } × 100% … (equation 3)

[ Table 1]

The negative radiation-sensitive resin compositions of examples 1 to 11 exhibit lithography performance, and even when heated at a relatively low temperature, can form an insulating film having sufficient hardness and being less likely to cause cracks such as cracks. In addition, it was confirmed that when the insulating film was formed from the negative radiation-sensitive resin compositions of examples 1 to 11, the occurrence of outgas was small, and the defects caused by the outgas could be reduced.

[ Industrial Applicability ]

The negative radiation-sensitive resin composition can be preferably used as a material for forming an insulating film used in an organic EL device.

Claims

1. A negative radiation-sensitive resin composition comprising:

(A) A polysiloxane having at least one thiol group;

(B) A multifunctional methacrylate; and

(C) A photopolymerization initiator,

the viscosity measured at 25 ℃ and 50rpm with an E-type viscometer is 0.5 mPas to 20 mPas.

2. The negative radiation-sensitive resin composition according to claim 1, wherein the (B) polyfunctional methacrylate is a tetrafunctional or higher methacrylate,

the mass ratio of the (B) polyfunctional methacrylate to the (A) polysiloxane having at least one thiol group is 1/2 or more and 2/1 or less.

3. The negative radiation-sensitive resin composition according to claim 1 or 2, wherein the (C) photopolymerization initiator is a compound comprising a structure represented by the following formula (1),

4. The negative radiation-sensitive resin composition according to claim 1 or 2, further comprising (D) an ultraviolet absorber,

the content ratio of the ultraviolet absorber (D) is 0.1 to 30 parts by mass with respect to 100 parts by mass of the polysiloxane (A) having at least one thiol group.

5. The negative radiation-sensitive resin composition according to claim 1 or 2, further comprising (E) a base generator,

the content ratio of the base generator (E) is 0.1 to 20 parts by mass with respect to 100 parts by mass of the polysiloxane (A) having at least one thiol group.

6. The negative radiation-sensitive resin composition according to claim 1 or 2, which is used for forming an insulating film for an organic electroluminescent element.

7. An insulating film for an organic electroluminescent element, which is formed from the negative radiation-sensitive resin composition according to claim 6.

8. A method for forming an insulating film for an organic electroluminescent element, comprising:

a step of forming a coating film by directly or indirectly applying the negative radiation-sensitive resin composition according to claim 6 on a substrate;

a step of irradiating at least a part of the coating film with radiation after the step of forming the coating film;

a step of developing the coating film after the step of irradiating the radiation; and

and a step of heating the coating film at a temperature of 60 ℃ to 120 ℃ after the step of developing.

9. An organic electroluminescent device comprising the insulating film for organic electroluminescent element according to claim 7.

10. A negative radiation-sensitive resin composition comprising:

(A) A polysiloxane having at least one thiol group;

(B) A multifunctional methacrylate; and

(C) A photopolymerization initiator.

11. An insulating film for an organic electroluminescent element, which is formed from the negative radiation-sensitive resin composition according to claim 10.

12. A method for forming an insulating film for an organic electroluminescent element, comprising:

a step of forming a coating film by directly or indirectly applying the negative radiation-sensitive resin composition according to claim 10 on a substrate;