KR102436922B1 - Head cleaning method for ink-jet printer - Google Patents

Abstract

The present application relates to a cleaning method of an inkjet printer head and an inkjet printing apparatus, and through efficient cleaning of an inkjet printer head in an inkjet process, ink ejection stability is ensured even when an organic electronic device is sealed using a photocurable composition as an ink composition And, to provide a method for cleaning an inkjet printer head and an inkjet printing apparatus capable of providing a highly reliable organic electronic device.

Description

How to clean an inkjet printer head {HEAD CLEANING METHOD FOR INK-JET PRINTER}

The present application relates to a cleaning method of an inkjet printer head and an inkjet printing apparatus.

In the inkjet printing-related industry, which has grown markedly in recent years, performance enhancement of inkjet printers, improvement of inks, etc. are progressing rapidly.

Various performance is calculated|required by the said ink every year with the performance improvement of inkjet printers etc. For example, the ink discharge stability which does not cause clogging of the ink discharge nozzle which comprises an inkjet printer with time, and does not produce ink discharge defect or abnormal discharge direction over a long period of time is mentioned.

In addition, when the ink material remains in the ink passage in the inkjet printer, a problem in which the ink material is partially cured in the flow passage may occur. Also, when the ink material is changed, a problem in which the materials are mixed with each other occurs. When such a problem occurs, when the organic electronic device is sealed using the photocurable composition as an ink, a fatal dark spot is generated in the organic electronic device, thereby shortening the lifespan of the organic electronic device.

The present application relates to an inkjet printer capable of securing ink ejection stability and providing a highly reliable organic electronic device even when an organic electronic device is sealed by using a photocurable composition as an ink composition through efficient cleaning of the inkjet printer head in the inkjet process. A method for cleaning a head and an inkjet printing apparatus are provided.

The present application relates to a cleaning method of an inkjet printer head. The inkjet printer may be applied to encapsulate or encapsulate an organic electronic device, such as an OLED, because patterning is possible in a non-contact manner. In particular, the inkjet printer uses a photocurable composition as an ink composition, and provides a method of cleaning such an inkjet printer head.

As used herein, the term "organic electronic device" refers to an article or device having a structure including an organic material layer that generates an exchange of electric charges using holes and electrons between a pair of electrodes facing each other, for example, may include, but are not limited to, a photovoltaic device, a rectifier, a transmitter, and an organic light emitting diode (OLED). In one example of the present application, the organic electronic device may be an OLED.

An exemplary method for cleaning an inkjet printer head may include injecting a positive pressure inert gas into an ink passage of the inkjet print head and injecting a cleaning solution into an ink passage of the head. Specifically, in the cleaning method, the inert gas may be supplied into the ink passage of the head. Accordingly, according to the present application, the inert gas may be injected in the nozzle direction from the inside of the ink flow path of the inkjet print head, and the inert gas may flow out to the nozzle. In addition, in the present application, the cleaning liquid may be injected after the inert gas is injected, and injection of the cleaning liquid before the inert gas may be excluded. In addition, in the present application, the inert gas is injected at a positive pressure, and suction with a negative pressure may be excluded. By controlling the conditions of the cleaning method, the present application prevents the photocurable composition from remaining in the inkjet printer and partially cured even when used as ink, thereby preventing nozzle clogging or mixing of ink materials, and in the above manner To provide an organic electronic device with excellent durability and reliability by preventing dark spots even at high temperature and high humidity by sealing the organic electronic device.

In an embodiment of the present application, the step of injecting the inert gas may have a pressure range of 3 to 8 kPa, 3.5 to 7.5 kPa, 3.8 to 7.0 kPa, 4.0 to 6.5 kPa, 4.3 to 6.0 kPa, or 4.6 to 5.2 kPa. . In addition, the step of injecting the inert gas may be performed for 100 to 300 seconds, 150 to 280 seconds, or 210 to 250 seconds. The type of the inert gas is not particularly limited, and may include nitrogen, argon, neon, helium, krypton, xenon, or radon. According to the present application, by controlling the injection condition of the inert gas, in cleaning for a specific ink composition to be described later, the remaining ink composition can be efficiently removed, and thus process cost can be reduced. In addition, in the present application, by injecting an inert gas instead of air, it is possible to prevent the photocurable composition from partially reacting or from introducing moisture into the flow path.

In one example, the step of injecting the cleaning solution may be performed two or more times or three or more times. The number of repetitions is not particularly limited, but may be 4 or more or 5 or more, and the upper limit may be 10 or less or 8 or less. According to the present application, process efficiency can be achieved while removing the remaining ink composition by controlling the number of injections of the cleaning solution.

The cleaning solution may use a material known in the art, for example, diethylene glycol monobutyl ether acetate, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, ethylene glycol dimethyl ether, ethylene glycol di Ethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, 2-ethoxy propanol, 2-methoxy propanol, 2-ethoxy Ethanol, 3-methoxybutanol, cyclohexanone, cyclopentanone, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, 3-methoxybutyl acetate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, methyl cellosolve acetate, butyl acetate, dipropylene glycol monomethyl ether, cyclohexene oxide or propylene carbonate.

In an embodiment of the present application, the inkjet printer may use a photocurable composition as an ink. Accordingly, the above-described cleaning method may be applied when the following photocurable composition is used as an ink, and may be a method of cleaning the following specific composition.

In one example, the photocurable composition may be a sealing material composition, for example, may be an encapsulant applied to encapsulating or encapsulating an organic electronic device such as OLED. In one example, the photocurable composition of the present application may be applied to encapsulating or encapsulating the entire surface of the organic electronic device. Therefore, after the photocurable composition is applied to the encapsulation, it may exist in the form of an organic layer that seals the front surface of the organic electronic device. In addition, the organic layer may be laminated on the organic electronic device together with the protective film and/or the inorganic layer to form an encapsulation structure.

Exemplary photocurable compositions may include a curable compound. More specifically, the photocurable composition of the present application may include a curable compound and a monofunctional curable compound having a cyclic structure in the molecular structure and having at least two or more curable functional groups. The monofunctional curable compound is 65 parts by weight to 165 parts by weight, 68 to 162 parts by weight, 73 to 160 parts by weight, 78 to 159 parts by weight, 85 to 158 parts by weight, or It may be included in the composition within the range of 90 to 157 parts by weight. As used herein, the term “parts by weight” may mean a weight ratio between each component. In addition, the photocurable composition of the present application may have a haze of 3% or less, 2% or less, or 1% or less according to the JIS K7105 standard test after curing, and the lower limit is not particularly limited, but may be 0% or 0.01%. Within the haze range, the photocurable composition may have excellent optical properties after curing. In addition, the present application is applied to an organic electronic device by adjusting the content ratio of the monofunctional curable compound and the curable compound having a cyclic structure to provide a composition capable of an inkjet process, the curing sensitivity of the cured product after curing, Excellent curing strength and surface strength.

In the present specification, the curable compound may refer to a compound having a curable functional group. The curable compound may include, for example, a curable compound having a cyclic structure and a monofunctional curable compound in the molecular structure described above, and a linear or branched aliphatic curable compound and/or a curable compound having an oxetane group to be described later. may include

In one example, the photocurable composition may further include a linear or branched aliphatic curable compound. The aliphatic curable compound may have at least two or more curable functional groups. In addition, the linear or branched aliphatic compound is 20 parts by weight or more, less than 205 parts by weight, 23 parts by weight to 204 parts by weight, 30 parts by weight to 203 parts by weight, 34 parts by weight based on 100 parts by weight of the compound having a cyclic structure. It may be included in the photocurable composition within the range of parts by weight to 202 parts by weight, 40 parts by weight to 201 parts by weight, 60 parts by weight to 200 parts by weight, or 100 parts by weight to 173 parts by weight. The present application relates to the implementation of optical properties by controlling the content ratio of the curable compound having the cyclic structure and the aliphatic curable compound to prevent haze due to unreacted or over-curing, and to realize optical properties and the characteristics of the organic layer composition directly applied to the organic electronic device. It is possible to prevent damage to the device and control its physical properties so that it can be applied to the device by an inkjet method.

In one example, the curable compound may be an epoxy compound, and in the case of an epoxy compound, the curable compound having a cyclic structure is 50 to 350 g/eq, 73 to 332 g/eq, 94 to 318 g/eq, or 123 to 298 g/eq. may have an epoxy equivalent in the range of In addition, the linear or branched aliphatic compound may have an epoxy equivalent of 120 e/eq to 375 e/eq or 120 e/eq to 250 e/eq. According to the present application, by adjusting the epoxy equivalent of the curable compound to a low level, it is possible to prevent the inkjet process from being impossible due to excessively high viscosity of the composition while improving the degree of completion of curing after curing of the sealing material, and at the same time moisture barrier properties and excellent curing sensitivity can provide In the present specification, the epoxy equivalent is the number of grams (g/eq) of a resin containing 1 gram equivalent of an epoxy group, and can be measured according to the method stipulated in JIS K 7236.

In an embodiment of the present application, the photocurable composition may further include a curable compound having an oxetane group. The oxetane group-curable compound may have at least two or more oxetane groups. In addition, the curable compound having an oxetane group is 50 parts by weight to 150 parts by weight, 55 to 145 parts by weight, 60 to 140 parts by weight, 65 to 100 parts by weight of the curable compound having a cyclic structure and the monofunctional curable compound. 140 parts by weight, 70 to 135 parts by weight, 75 to 130 parts by weight, 80 to 125 parts by weight, 85 to 120 parts by weight, or 88 to 115 parts by weight may be included. According to the present application, by controlling the content ratio between the curable compounds, an organic layer can be formed on an organic electronic device by an inkjet method, the applied photocurable composition has excellent spreadability within a short time, and nozzle clogging is prevented due to low viscosity and can provide an organic layer having excellent curing strength after curing.

The compound having the oxetane group may have a weight average molecular weight of 150 to 1,000 g/mol, 173 to 980 g/mol, 188 to 860 g/mol, 210 to 823 g/mol, or 330 to 780 g/mol. According to the present application, by controlling the weight average molecular weight of the compound having an oxetane group to be low, excellent printability can be realized when applied to inkjet printing while at the same time providing moisture barrier properties and excellent curing sensitivity. In the present specification, the weight average molecular weight means a value converted to standard polystyrene measured by Gel Permeation Chromatograph (GPC). In one example, a column consisting of a metal tube having a length of 250 to 300 mm and an inner diameter of 4.5 to 7.5 mm is filled with 3 to 20 mm Polystyrene beads. When a diluted solution of a substance to be measured is dissolved in a THF solvent is passed through a column, the weight average molecular weight can be measured indirectly according to the time it flows out. The amount separated by size from the column can be detected by plotting each time.

Further, the compound having an oxetane group may have a boiling point in the range of 90 to 300°C, 98 to 270°C, 110 to 258°C, or 138 to 237°C. In the present application, by controlling the boiling point of the compound in the above range, it is possible to realize excellent printability even at a high temperature in the inkjet process, excellent moisture barrier properties from the outside, and a sealing material that can prevent damage to the device by suppressing outgas. of can be provided. In the present specification, unless otherwise specified, the boiling point may be measured at 1 atm.

In one example, the photocurable composition of the present application may have a contact angle with respect to glass of 30° or less, 25° or less, 20° or less, 15° or less, or 12° or less. The lower limit is not particularly limited, but may be 1° or 3° or more. In the present application, by adjusting the contact angle to 30° or less, spreadability can be secured within a short time in inkjet coating, and thus a thin organic layer can be formed. In the present application, the contact angle may be measured by applying one drop of the photocurable composition on glass using a sessile drop measurement method, and may be an average value measured after applying five times.

In the present application, the curable functional group of the aforementioned curable compound is selected from, for example, an oxetane group, a glycidyl group, an isocyanate group, a hydroxyl group, a carboxyl group, an amide group, an epoxide group, a sulfide group, an acetal group and a lactone group. There may be more than one.

In an embodiment of the present application, the photocurable composition may include a compound having a cyclic structure in a molecular structure as a curable compound, as described above. In one example, the compound having a cyclic structure in the molecular structure may have 3 to 10, 4 to 8, or 5 to 7 ring constituent atoms in the molecular structure, and 1 or 2 or more, 10 or less of the cyclic structure in the compound can exist as The compound having the cyclic structure is based on 100 parts by weight of the total curable compound, 10 parts by weight to 50 parts by weight, 12 parts by weight to 45 parts by weight, 14 parts by weight to 40 parts by weight, 15 parts by weight to 35 parts by weight, 16 parts by weight. It may be included in an amount of parts by weight to 28 parts by weight or 16 parts by weight to 22 parts by weight. By controlling the content range, the present application allows the photocurable composition to have suitable physical properties in full sealing of the organic electronic device, to have excellent curing strength after curing, and to realize excellent moisture barrier properties together.

In one example, the compound having a cyclic structure in the molecular structure is 3,4-epoxycyclohexylmethyl 3',4'-epoxycyclohexanecarboxylate (EEC) and derivatives, dicyclopentadiene dioxide and derivatives, vinylcyclohexene Dioxide and derivatives, 1,4-cyclohexanedimethanol bis(3,4-epoxycyclohexanecarboxylate) and derivatives can be exemplified, but are not limited thereto.

In the present specification, the curable compound having a cyclic structure may be an aliphatic compound, and may be distinguished from a linear or branched aliphatic compound in that it has a cyclic structure. In addition, the curable compound having an oxetane group may be a linear, branched or cyclic aliphatic compound, but may be distinguished from the aforementioned two compounds in that it has an oxetane group. In addition, the monofunctional curable compound may be distinguished from the three compounds as a compound having one curable functional group.

In one example, the structure of the curable compound including the oxetane group is not limited as long as it has the functional group, for example, TOAGOSEI's OXT-121, CHOX, OX-SC, OXT101, OXT121, OXT221 or OXT212, Or EHO, OXBP, OXTP or OXMA from ETERNACOLL can be exemplified. In addition, linear or branched aliphatic curable compounds include aliphatic glycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycyl. Contains cidyl ether, propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether or neopentylglycol diglycidyl ether can, but is not limited thereto. In addition, the monofunctional curable compound may include an aliphatic alcohol glycidyl ether, and an alkyl carboxylic acid glycidyl ester.

In an embodiment of the present application, the photocurable composition may further include a surfactant. In one example, the surfactant may include a polar functional group, and the polar functional group may be present at the end of the compound structure of the surfactant. The polar functional group may include, for example, a carboxyl group, a hydroxyl group, a phosphate, an ammonium salt, a carboxylate group, a sulfate or a sulfonate. In addition, in the embodiment of the present application, the surfactant may be a non-silicone-based surfactant or a fluorine-based surfactant. The non-silicone-based surfactant or fluorine-based surfactant is applied together with the above-described curable compound to provide excellent coating properties on the organic electronic device. On the other hand, in the case of a surfactant including a polar reactive group, an excellent effect can be realized in terms of adhesion because the affinity with other components of the photocurable composition is high. In an embodiment of the present application, a hydrophilic fluorine-based surfactant or a non-silicone-based surfactant may be used to improve coating properties on a substrate.

Specifically, the surfactant may be a polymer-type or oligomeric-type fluorine-based surfactant. Commercially available surfactants may be used as the surfactant, for example, TEGO's Glide 100, Glide110, Glide 130, Glide 460, Glide 440, Glide450 or RAD2500, DIC (DaiNippon Ink & Chemicals)'s Megaface F-251, F-281, F-552, F552, F-560, F-561, F-562, F-563, F-565, F-568, F-570 and F-571 or Surflon S-111, S-112 from Asahi Glass. , S-113, S-121, S-131, S-132, S-141 and S-145 or Sumitomo 3M's Fluorad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430 and FC-4430 or Zonyl FS-300, FSN, FSN-100 and FSO from DuPont and BYK-350, BYK-354, BYK-355, BYK-356, BYK-358N, BYK from BYK -359, BYK-361N, BYK-381, BYK-388, BYK-392, BYK-394, BYK-399, BYK-3440, BYK-3441, BYKETOL-AQ, BYK-DYNWET 800, etc. selected from the group consisting of that can be used

The surfactant is 0.01 to 10 parts by weight, 0.05 to 10 parts by weight, 0.1 to 10 parts by weight, 0.5 to 8 parts by weight, or 1 to 4 parts by weight based on 100 parts by weight of the total curable compound. may be included as a part. Within the above content range, the present application allows the photocurable composition to be applied to an inkjet method to form a thin organic layer.

In an embodiment of the present application, the photocurable composition may further include a photoinitiator. The photoinitiator may be an ionic photoinitiator. In addition, the photoinitiator may be a compound that absorbs a wavelength in the range of 200 nm to 400 nm. In the present application, by using the photoinitiator, excellent curing properties can be implemented in the specific composition of the present application.

In one example, the photoinitiator may be a cationic photopolymerization initiator. In the case of a cationic photopolymerization initiator, a material known in the art may be used, for example, a cation moiety containing aromatic sulfonium, aromatic iodonium, aromatic diazonium or aromatic ammonium and AsF ₆ ^- , SbF ₆ ^- , PF ₆ ^- , or a compound having an anionic moiety comprising tetrakis(pentafluorophenyl)borate. In addition, as the cationic photopolymerization initiator, an onium salt or organometallic salt-based ionized cationic initiator or an organosilane or latent sulfonic acid-based or non-ionized cationic photopolymerization initiator may be exemplified. . Examples of the onium salt-based initiator include a diaryliodonium salt, a triarylsulfonium salt, or an aryldiazonium salt, and the initiation of an organometallic salt-based initiator. The zero may be exemplified by iron arene, and the like, and as the organosilane-based initiator, o-nitrobenzyl triaryl silyl ether, triaryl silyl peroxide, etc. Alternatively, acyl silane may be exemplified, and the latent sulfuric acid-based initiator may include α-sulfonyloxy ketone or α-hydroxymethylbenzoin sulfonate, but is not limited thereto. .

In one example, the photocurable composition of the present application may include a photoinitiator including a sulfonium salt as a photoinitiator in the specific composition described above so as to be suitable for use in sealing an organic electronic device by an inkjet method. Although the photocurable composition according to the composition is directly sealed on the organic electronic device, the amount of outgas generated is small, so that chemical damage to the device can be prevented. In addition, the photoinitiator including the sulfonium salt has excellent solubility and can be suitably applied to the inkjet process.

In an embodiment of the present application, the photoinitiator may be included in an amount of 1 to 15 parts by weight, 2 to 13 parts by weight, or 3 to 11 parts by weight based on 100 parts by weight of the total curable compound. In the present application, by controlling the content range of the photoinitiator, physical and chemical damage to the device can be minimized due to the nature of the composition directly on the organic electronic device.

In an embodiment of the present application, the photocurable composition may further include a photosensitizer to compensate for curability in long-wavelength active energy rays of 300 nm or more. The photosensitizer may be a compound that absorbs a wavelength in a range of 200 nm to 400 nm.

The photosensitizer may include anthracene-based compounds such as anthracene, 9,10-dibutoxyanthracene, 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, and 2-ethyl-9,10-dimethoxyanthracene; Benzophenone, 4,4-bis(dimethylamino)benzophenone, 4,4-bis(diethylamino)benzophenone, 2,4,6-trimethylaminobenzophenone, methyl-o-benzoylbenzoate, 3,3 -benzophenone compounds, such as dimethyl-4-methoxybenzophenone and 3,3,4,4-tetra(t-butylperoxycarbonyl)benzophenone; acetophenone; ketone compounds such as dimethoxyacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one and propanone; perylene; fluorenone compounds such as 9-fluorenone, 2-chloro-9-prorenone, and 2-methyl-9-fluorenone; Thioxanthone, 2,4-diethyl thioxanthone, 2-chloro thioxanthone, 1-chloro-4-propyloxy thioxanthone, isopropyl thioxanthone (ITX), diisopropyl thioxanthone, etc. thioxanthone-based compounds; xanthone-based compounds such as xanthone and 2-methylxanthone; anthraquinone compounds such as anthraquinone, 2-methyl anthraquinone, 2-ethyl anthraquinone, t-butyl anthraquinone, and 2,6-dichloro-9,10-anthraquinone; 9-phenylacridine, 1,7-bis(9-acridinyl)heptane, 1,5-bis(9-acridinylpentane), 1,3-bis(9-acridinyl)propane, etc. acridine-based compounds; dicarbonyl compounds such as benzyl, 1,7,7-trimethyl-bicyclo[2,2,1]heptane-2,3-dione, and 9,10-phenanthrenequinone; phosphine oxide compounds such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide; benzoate compounds such as methyl-4-(dimethylamino)benzoate, ethyl-4-(dimethylamino)benzoate, and 2-n-butoxyethyl-4-(dimethylamino)benzoate; 2,5-bis(4-diethylaminobenzal)cyclopentanone, 2,6-bis(4-diethylaminobenzal)cyclohexanone, 2,6-bis(4-diethylaminobenzal)-4- amino synergists such as methyl-cyclopentanone; 3,3-carbonylvinyl-7-(diethylamino)coumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 3-benzoyl-7-(diethylamino)coumarin, 3 -benzoyl-7-methoxy-coumarin, 10,10-carbonylbis[1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-C1]-benzo coumarin-based compounds such as pyrano[6,7,8-ij]-quinolizin-11-one; chalcone compounds such as 4-diethylamino chalcone and 4-azidebenzalacetophenone; 2-benzoylmethylene; and 3-methyl-b-naphthothiazoline may be at least one selected from the group consisting of.

The photosensitizer may be included in the range of 28 parts by weight to 40 parts by weight, 31 parts by weight to 38 parts by weight, or 32 parts by weight to 36 parts by weight based on 100 parts by weight of the photoinitiator. According to the present application, by controlling the content of the photosensitizer, it is possible to prevent the photosensitizer from being dissolved and thereby lowering the adhesion while realizing the synergistic action of curing sensitivity at a desired wavelength.

The photocurable composition of the present application may further include a coupling agent. The present application can improve the adhesion of the cured product of the photocurable composition to the adherend or the moisture permeability resistance of the cured product. The coupling agent may include, for example, a titanium-based coupling agent, an aluminum-based coupling agent, or a silane coupling agent.

In an embodiment of the present application, as the silane coupling agent, specifically, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyl (dimethy epoxy-based silane coupling agents such as oxy)methylsilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; mercapto-based silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane and 11-mercaptoundecyltrimethoxysilane; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, N-phenyl-3-aminopropyltrimethoxysilane, N-methylaminopropyltrimethoxysilane, amino-based silane coupling agents such as N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropyldimethoxymethylsilane; urea-based silane coupling agents such as 3-ureidepropyltriethoxysilane, vinyl-based silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinylmethyldiethoxysilane; styryl-based silane coupling agents such as p-styryltrimethoxysilane; acrylate-based silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane; isocyanate-based silane coupling agents such as 3-isocyanatepropyltrimethoxysilane, sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)disulfide and bis(triethoxysilylpropyl)tetrasulfide; Phenyl trimethoxysilane, methacryloxy propyl trimethoxysilane, imidazole silane, triazine silane, etc. are mentioned.

In the present application, the coupling agent may be included in an amount of 0.1 parts by weight to 10 parts by weight or 0.5 parts by weight to 5 parts by weight based on 100 parts by weight of the total curable compound. The present application can implement the effect of improving the adhesion by the addition of the coupling agent within the above range.

The photocurable composition of the present application may include a moisture absorbent, if necessary. The term “moisture adsorbent” may be used as a generic term for components capable of adsorbing or removing moisture or moisture introduced from the outside through a physical or chemical reaction. That is, it means a moisture-reactive adsorbent or a physical adsorbent, and a mixture thereof may also be used.

The specific type of the moisture adsorbent that can be used in the present application is not particularly limited, and for example, in the case of the moisture-reactive adsorbent, one or more types of mixtures such as metal oxide, metal salt, or phosphorus pentoxide (P ₂ O ₅ ) may be mentioned. and in the case of a physical adsorbent, zeolite, zirconia, or montmorillonite may be mentioned.

The photocurable composition of the present application contains the moisture absorbent in an amount of 5 to 100 parts by weight, 5 to 80 parts by weight, 5 to 70 parts by weight, or 10 to 30 parts by weight based on 100 parts by weight of the total curable compound. can do. The photocurable composition of the present application preferably controls the content of the moisture absorbent to 5 parts by weight or more, so that the photocurable composition or a cured product thereof exhibits excellent moisture and moisture barrier properties. In addition, the present application may provide an encapsulation structure of a thin film by controlling the content of the moisture absorbent to 100 parts by weight or less.

In one example, the photocurable composition may further include an inorganic filler, if necessary. Specific types of fillers that can be used in the present application are not particularly limited, and for example, one or a mixture of two or more types of clay, talc, alumina, calcium carbonate or silica may be used.

The photocurable composition of the present application contains 0 parts by weight to 50 parts by weight, 1 part by weight to 40 parts by weight, 1 part by weight to 20 parts by weight, or 1 to 10 parts by weight of the inorganic filler based on 100 parts by weight of the total curable compound. can do. The present application may provide an encapsulation structure having excellent moisture or moisture barrier properties and mechanical properties by controlling the inorganic filler to preferably be 1 part by weight or more. In addition, the present invention can provide a cured product exhibiting excellent moisture barrier properties even when formed as a thin film by controlling the inorganic filler content to 50 parts by weight or less.

In addition to the above-described configuration, the photocurable composition according to the present application may include various additives within a range that does not affect the effects of the above-described invention. For example, the photocurable composition may include an antifoaming agent, a tackifier, a UV stabilizer, or an antioxidant in an appropriate range according to desired physical properties.

In one example, the photocurable composition may be liquid at room temperature, for example, about 25°C. In an embodiment of the present application, the photocurable composition may be a liquid in a solvent-free form. The photocurable composition may be applied to encapsulating an organic electronic device, and specifically, may be applied to encapsulating the entire surface of an organic electronic device. In the present application, since the photocurable composition has a liquid form at room temperature, the device can be encapsulated by applying the composition to the side of the organic electronic device.

In addition, the photocurable composition of the present application may be an ink composition. The photocurable composition of the present application may be an ink composition capable of an inkjet process. The photocurable composition of the present application may have a specific composition and physical properties to enable inkjetting.

In one example, in the photocurable composition of the present application, the amount of the volatile organic compound measured after curing may be less than 50 ppm. The volatile organic compound may be measured after curing the photocurable composition and maintaining the cured product sample at 110° C. for 30 minutes using a Purge & Trap-gas chromatography/mass spectrometry method. The measurement may be performed using a Purge & Trap sampler (JAI JTD-505Ⅲ)-GC/MS (Agilent 7890b/5977a) instrument.

In addition, in an embodiment of the present application, the photocurable composition has a viscosity of 50 cPs or less, 1 to 46 cPs, or 5 at a temperature of 25° C., a torque of 90%, and a shear rate of 100 rpm, as measured by Brookfield's DV-3. to 44 cPs. The present application can provide an encapsulant of a thin film by controlling the viscosity of the composition in the above range, thereby improving the coatability at the time of application to the organic electronic device.

In addition, in an embodiment of the present application, the photocurable composition may have a light transmittance of 90% or more, 92% or more, or 95% or more in a visible light region after curing. Within the above range, the present application provides an organic electronic device with high resolution, low power consumption and long life by applying the photocurable composition to a top emission type organic electronic device. In addition, the photocurable composition of the present application may have a haze of 3% or less, 2% or less, or 1% or less according to the JIS K7105 standard test after curing, and the lower limit is not particularly limited, but may be 0%. Within the haze range, the photocurable composition may have excellent optical properties after curing. In the present specification, the above-described light transmittance or haze may be measured in a state in which the photocurable composition is cured into an organic layer, and may be an optical characteristic measured when the thickness of the organic layer is any one of 2 μm to 50 μm. have. In an embodiment of the present application, in order to implement the optical properties, the above-described moisture absorbent or inorganic filler may not be included.

The present application also relates to an inkjet printing apparatus. The inkjet printing apparatus of the present application may include a pneumatic apparatus for injecting an inert gas of positive pressure into the ink passage of the inkjet printhead.

The present application does not include a separate cleaning device other than the inkjet printing device, and cleaning can be performed through a pneumatic device in the inkjet printing device, so that process efficiency can be realized. In addition, the present application can effectively remove the photocurable composition ink by injecting an inert gas at a positive pressure.

In an embodiment of the present application, the inkjet printing apparatus may further include a pressure adjusting unit for adjusting the inert gas injection pressure. Through the control unit, it is possible to provide an inert gas in the above-described pressure range.

In one example, the pneumatic device may discharge the inert gas in the nozzle direction from the inside of the ink flow path of the inkjet print head. Thus, it is distinguished from injecting air outside the nozzle through a cleaning device existing outside the nozzle.

In one example, the present application does not separately include the cleaning liquid supply device, and the cleaning liquid may be supplied by injecting the cleaning liquid into the ink passage of the inkjet print head.

In addition, in an embodiment of the present application, the inkjet printing apparatus may further include an ink receiving unit. The ink receiving unit may be a storage space for ink, and may include the aforementioned photocurable composition ink.

The present application relates to an inkjet printer capable of securing ink ejection stability and providing a highly reliable organic electronic device even when an organic electronic device is sealed by using a photocurable composition as an ink composition through efficient cleaning of the inkjet printer head in the inkjet process. A method for cleaning a head and an inkjet printing apparatus are provided.

Hereinafter, the present invention will be described in more detail through Examples according to the present invention and Comparative Examples not according to the present invention, but the scope of the present invention is not limited by the Examples presented below.

Example One

As a curable compound at room temperature, alicyclic epoxy compound (Celloxide 2021P from Daicel), aliphatic epoxy compound 1,4-butanediol diglycidyl ether (DE200, HAJIN CHEM TECH), monofunctional curable compound o-cresylglycidyl ether (HAJIN CHEM TECH) and an oxetane group-containing curable compound (TOAGOSEI's OXT-121) in a weight ratio of 16:18:18:39.95 (Celloxide2021P:DE200:o-cresylglycidyl ether:OXT-121) It was put into the mixing vessel. Based on 100 parts by weight of the total curable compound, 3.3 parts by weight of a photopolymerization initiator (BASF's Irgacure PAG 290, hereinafter, I290), 1.1 parts by weight of a fluorine-based surfactant (DIC's F552), 3.3 parts by weight of a coupling agent (KBM-303, SHIN) -ETSU) and 0.05 parts by weight of a heat stabilizer 2,6-di-tert-Butyl-alpha-methoxy-para-cresol (SIGMA aldrich) were additionally added to the mixing vessel. In addition, 33.3 parts by weight of the photosensitizer 9,10-Dibutoxyanthracene (SIGMA Aldrich's DBA) was added to the mixing vessel based on 100 parts by weight of the photopolymerization initiator.

A uniform photo-curable composition ink was prepared using the mixing vessel in a Planetary mixer (Kurabo, KK-250s).

An organic layer was formed by inkjetting 50 ml of the ink composition prepared above on a polyethylene substrate (PE, DIAFOIL manufactured by Mitsubishi) using a Unijet UJ-200 (Inkjet head-Dimatix 10Pl 256).

Thereafter, nitrogen gas was injected into the ink passage at 4.8 kPa for 240 seconds using the meniscus pressure control unit mounted in the inkjet printer head, and then a cleaning solution (diethylene glycol monobutyl ether acetate) into the passage. 50ml was injected. The washing solution was repeatedly injected a total of 3 times.

Example 2

Inkjet printhead cleaning was performed in the same manner as in Example 1, except that the cleaning solution was repeatedly injected 5 times.

comparative example One

Inkjet print head cleaning was performed in the same manner as in Example 1, except that 50 ml of the cleaning solution (diethylene glycol monobutyl ether acetate) was repeated three times without injecting inert gas.

comparative example 2

Inkjet printhead cleaning was performed in the same manner as in Comparative Example 1, except that the cleaning solution was repeatedly injected 5 times.

comparative example 3

Inkjet printhead cleaning was performed in the same manner as in Example 1, except that air instead of nitrogen gas was injected into the ink passage.

comparative example 4

Inkjet printhead cleaning was performed in the same manner as in Comparative Example 3, except that the cleaning solution was repeatedly injected 5 times.

comparative example 5

After repeating the injection of 50 ml of the cleaning solution (diethylene glycol monobutyl ether acetate) three times before the injection of nitrogen gas, nitrogen gas was injected, and then the cleaning solution was added once more to perform cleaning. Inkjet print head cleaning was performed in the same manner as in 1.

comparative example 6

Inkjet printhead cleaning was performed in the same manner as in Comparative Example 5, except that the cleaning solution was repeatedly injected 5 times.

comparative example 7

The inkjet printhead was cleaned in the same manner as in Example 1, except that nitrogen gas was sprayed from the outside of the inkjet print nozzle and the nozzle was washed by immersing the nozzle in a container containing a cleaning solution (repeated 3 times).

comparative example 8

Inkjet printhead cleaning was performed in the same manner as in Comparative Example 7, except that the container containing the cleaning solution was repeatedly washed 5 times.

One. photocurable Determination of the remaining amount of the composition

In the cleaning methods of Examples and Comparative Examples, when the residual amount of the photocurable composition material present in 50ml of the first cleaning solution is 100, the remaining amount of the photocurable composition material present in 50ml of the last cleaning solution is measured relative to the % in the table below. described.

It was measured based on the peak (epoxy peak) of one raw material of the photocurable composition, and was measured using gas chromatography/mass spectrometry.

2. Outgas Measurement

After the cleaning method in Examples and Comparative Examples, 50ml of the same photocurable composition ink as in Example 1 was inkjetted on a glass substrate (10x10cm) using Unijet UJ-200 (Inkjet head-Dimatix 10Pl 256) to have a thickness of 5㎛ of an organic layer was formed.

In the organic layer, a 5x1 cm area in the center of the glass was cut and used as a sample. After purge and trap was performed at 110° C. for 30 minutes, the amount of volatile organic compounds was measured using gas chromatography/mass spectrometry.

Measuring instrument: Purge & Trap sampler-GC/MSD system (P & T: JAI JTD-505Ш, GC/MS: Agilent 7890B/5977A)

3. Evaluation of durability and reliability of organic electronic devices

An organic electronic device that can be tested for lighting is deposited on a glass substrate.

After the cleaning method in Examples and Comparative Examples, 50 ml of the same photocurable composition ink as in Example 1 was used to seal the entire surface of the organic electronic device on the glass substrate using Unijet UJ-200 (Inkjet head-Dimatix 10Pl 256). An organic layer was formed.

Observe the dark spots in the sample under 85 ℃ 85% RH constant temperature, constant humidity conditions. When there is no dark spot generated by observing for 300 hours, it is classified as O, when dark spots occur in less than 3% of the total area, △, and when dark spots occur in 3% or more, it is classified as X.

Residual amount of photocurable composition (%) outgas Durable Reliability Example 1 2.1 less than 30 ppm O Comparative Example 1 25.5 100 ppm X Comparative Example 3 3.2 50 ppm △ Comparative Example 5 24.8 100 ppm X Comparative Example 7 26.7 100 ppm X

Residual amount of photocurable composition (%) outgas Durable Reliability Example 2 0.7 less than 30 ppm O Comparative Example 2 10.6 100 ppm X Comparative Example 4 1.1 50 ppm △ Comparative Example 6 6.8 100 ppm X Comparative Example 8 10.2 100 ppm X

Claims (14)

A method of cleaning an inkjet printhead, comprising: injecting an inert gas of positive pressure into an ink passage of an inkjet printhead; and injecting a cleaning solution into an ink passage of the head after injecting the inert gas. The method of claim 1, wherein the injecting of the inert gas has a pressure range of 3 to 8 kPa. The method of claim 1 , wherein the injecting of the inert gas is performed for 100 to 300 seconds. The method of claim 1, wherein the inert gas includes nitrogen, argon, neon, helium, krypton, xenon, or radon. The method of claim 1 , wherein in the injecting of the inert gas, the inert gas is injected in the nozzle direction from the inside of the ink passage of the inkjet printer head, and the inert gas flows out to the nozzle. The method of claim 1 , wherein the injecting of the cleaning solution is performed two or more times. According to claim 1, wherein the cleaning solution is diethylene glycol monobutyl ether acetate, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol Diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, 2-ethoxy propanol, 2-methoxy propanol, 2-ethoxy ethanol, 3-methoxy butanol, cyclohexa Non, cyclopentanone, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, 3-methoxybutyl acetate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, methyl cellosolve acetate, butyl acetate, dipropylene glycol A method for cleaning an inkjet printer head comprising monomethyl ether, cyclohexene oxide or propylene carbonate. The method of claim 1, wherein the photocurable composition is used as the ink. The monofunctional composition according to claim 8, wherein the photocurable composition has a cyclic structure in the molecular structure and is in the range of 65 parts by weight to 165 parts by weight based on 100 parts by weight of the curable compound having at least two or more curable functional groups and the curable compound having the cyclic structure. A method for cleaning an inkjet printer head comprising a curable compound. Including a pneumatic device for injecting an inert gas of positive pressure into the ink passage of the inkjet print head,
It includes an ink receiving unit containing the photocurable composition ink,
The photocurable composition ink has a cyclic structure in its molecular structure and includes a curable compound having at least two or more curable functional groups. The inkjet printing apparatus according to claim 10, further comprising a pressure adjusting unit for adjusting the inert gas injection pressure. The inkjet printing apparatus of claim 10 , wherein the pneumatic device discharges the inert gas in the direction of the nozzle from the inside of the ink passage of the inkjet printhead. 11. The inkjet printing apparatus of claim 10, wherein the photocurable composition ink further comprises a monofunctional curable compound. The inkjet printing apparatus of claim 10 , wherein the photocurable composition ink further comprises a linear or branched aliphatic curable compound.