Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
  • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
  • C04B35/632—Organic additives
  • C04B35/634—Polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
  • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
  • C08F20/10—Esters
  • C08F20/12—Esters of monohydric alcohols or phenols
  • C08F20/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
  • C08F20/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical

Definitions

• the present invention relates to a resin, a paste composition, an inorganic sintered body, an electronic device, and a solar panel.
• Inorganic molded bodies and patterns formed from such molded bodies are sometimes used for the internal electrode layers and external electrodes of multilayer electronic components such as multilayer ceramic capacitors, and for solar cell electrodes.
• a known method for forming such molded bodies and patterns is to mix an inorganic compound such as a metal powder, a metal oxide powder, a fluorescent powder, or a glass frit with a binder resin to prepare a paste composition, and then use this paste composition to mold into a predetermined shape to form a molded body or a pattern, and then bake to thermally decompose the binder resin.
• the binder resin used in this process improves the processability during molding and binds the inorganic compounds so that they are not damaged during transportation.
• This binder resin is removed by thermal decomposition when the inorganic compounds are sintered before becoming the final product, so it is required to have high thermal decomposition properties and excellent workability during each processing.
• the binder resin for this application is required to be in a solvent-free solid state and to be easily soluble in a solvent, since the viscosity range can be easily changed by adjusting the amount added during compounding, and the binder resin has a wide range of solvent selectivity.
• Known methods for processing paste compositions include screen printing, forming into a sheet using a doctor blade or the like, dipping, and dispensing.
• screen printing the higher the thixotropy of the paste composition, the better the printability and leveling after printing. Therefore, when screen printing, a paste composition with high thixotropy is required.
• Patent Document 1 discloses crosslinked fine particles which are (meth)acrylic resins containing 20 to 55 mass % of constituent units derived from a monofunctional (meth)acrylic ester having 1 to 4 carbon atoms in the ester moiety and 45 to 80 mass % of constituent units derived from a polyfunctional (meth)acrylic ester having an alkylene glycol moiety having 2 to 4 carbon atoms and having an average particle size of 0.1 to 0.5 ⁇ m, and which have a heating residue amount of 0.3 mass % or less when heated to 500° C. at a rate of 5° C./min in an air atmosphere.
• Patent Document 2 discloses a binder resin for conductive paste that is excellent in thixotropy and thermal decomposition properties due to a polymer having a specific structure that has a hydroxyurethane structure.
• An object of the present invention is to provide a resin, a paste composition, an inorganic sintered body, an electronic device, and a solar panel which have excellent solvent solubility, thermal decomposition properties, and high thixotropy.
• the present invention relates to the following items [1] to [16].
• a resin having a structural unit derived from a (meth)acrylic acid ester and a chemical structure derived from a mercaptan having two or more SH groups, wherein the ratio Mw/Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 5.0 or more.
• Mw weight average molecular weight
• Mn number average molecular weight
• the resin of [1] above, wherein the resin is a solid sintering binder.
• the resin according to any one of [1] to [9] above having a weight average molecular weight of 10,000 to 1,000,000.
• the resin according to any one of [1] to [10] above having a water content of 0.01 to 10% by mass based on the total mass of the resin.
• a paste composition comprising the resin according to any one of [1] to [11] above, a metal or an inorganic compound, and an organic solvent.
• An electronic device comprising the inorganic sintered body according to [14].
• a solar panel having the inorganic sintered body according to [14].
• the present invention provides resins, paste compositions, inorganic sintered bodies, electronic devices, and solar panels that have excellent solvent solubility, thermal decomposition properties, and high thixotropy.
• (meth)acrylic is a general term for acrylic and methacrylic.
• (meth)acrylate is a general term for acrylate and methacrylate.
• (meth)acryloyl is a general term for acryloyl and methacryloyl.
• polymerizable double bond means a double bond capable of radical polymerization.
• room temperature means 5 to 30°C.
• the term "to" indicating a range of values means that the values before and after it are included as the lower and upper limits.
• the resin of the present embodiment has a structural unit (a1) derived from a (meth)acrylic acid ester (hereinafter also referred to as "monomer (a1)”) and a chemical structure (b1) derived from a mercaptan having two or more SH groups, and has a ratio Mw/Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 5.0 or more.
• the ratio Mw/Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 5.5 or more, more preferably 10 or more, even more preferably 15 or more, particularly preferably 30 or more, and most preferably 35 or more. Also, it is preferably 100 or less, more preferably 80 or less, even more preferably 60 or less, and particularly preferably 40 or less. The above upper and lower limits can be combined in any combination.
• it may be 5.0 to 100, 5.5 to 100, 10 to 100, 30 to 100, 35 to 100, 5.0 to 80, 10 to 80, 15 to 80, 30 to 80, 35 to 80, 5.0 to 60, 10 to 60, 15 to 60, 30 to 60, 35 to 60, 5.0 to 40, 10 to 40, 15 to 40, 30 to 40, or 35 to 40.
• the solvent solubility, thermal decomposition property, and thixotropy are improved by increasing the ratio of the low molecular weight component.
• the ratio Mw/Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the resin can be adjusted, for example, by increasing the ratio of the structural unit (a2) to all structural units of the resin to increase the value of the ratio Mw/Mn, or by decreasing the ratio of the structural unit (a2) to all structural units of the resin to decrease the value of the ratio Mw/Mn.
• the weight average molecular weight (Mw) and number average molecular weight (Mn) of the resin are values calculated as standard polystyrene by gel permeation chromatography (GPC). The detailed measurement conditions are as described in the examples below.
• the resin preferably further has at least one of a structural unit (a2) derived from a monomer having two or more polymerizable double bonds (hereinafter also referred to as "monomer (a2)”), and a chemical structure (b2) derived from a mercaptan having one SH group.
• the resin may further include a structural unit (a3) derived from a monomer other than the monomer (a1) and the monomer (a2) (hereinafter, also referred to as "monomer (a3)").
• the monomer (a1) is a (meth)acrylic acid ester.
• the monomer (a1) is a monofunctional monomer having one polymerizable double bond, specifically having one (meth)acryloyl group as a functional group having a polymerizable double bond.
• Examples of the monomer (a1) include alkyl (meth)acrylates having a straight or branched hydrocarbon skeleton, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, i-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and 4-t-butylcyclohexyl (meth)acrylate; Alkyl (meth)acryl
• alkyl(meth)acrylates having a linear or branched hydrocarbon skeleton are preferred, and from the viewpoint of versatility in particular, methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate, i-propyl(meth)acrylate, n-butyl(meth)acrylate, i-butyl(meth)acrylate, t-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, and lauryl(meth)acrylate are more preferred.
• the monomer (a1) may be used alone or in combination of two or more kinds.
• the proportion of the structural unit (a1) in the resin is preferably 70.0 to 100% by mass, more preferably 90.0 to 99.9% by mass, even more preferably 95.0 to 99.7% by mass, particularly preferably 97.0 to 99.5% by mass, and most preferably 99.0 to 99.5% by mass. If it is equal to or greater than the lower limit, the thermal decomposition property of the resin is further improved. If it is equal to or less than the upper limit, the thixotropy of the resin is further improved.
• the monomer (a2) is a monomer having two or more polymerizable double bonds.
• the monomer (a2) may be a polyfunctional monomer having two or more (meth)acryloyl groups as a functional group having a polymerizable double bond.
• Examples of the monomer (a2) include polyfunctional alkyl (meth)acrylates having a linear or branched hydrocarbon skeleton, such as ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; polyfunctional polyalkoxylene (meth)acrylates such as polyethylene glycol di(me
• polyfunctional alkyl (meth)acrylates having a linear or branched hydrocarbon skeleton are preferred, and from the viewpoint of crosslink density in particular, ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate are more preferred.
• the monomer (a2) may be used alone or in combination of two or more kinds.
• the proportion of the structural unit (a2) in the resin is preferably 0 to 20% by mass, more preferably 0.01 to 20% by mass, even more preferably 0.1 to 10% by mass, particularly preferably 0.1 to 6% by mass, especially preferably 0.1 to 5.0% by mass, and most preferably 0.3 to 5.0% by mass, when the total of all structural units constituting the resin is taken as 100% by mass. If it is equal to or greater than the lower limit, the thixotropy when the resin is dissolved in a solvent is improved. If it is equal to or less than the upper limit, the solvent solubility of the resin is improved. If it is within the above range, the resin has an appropriate degree of crosslinking, resulting in good thixotropy and solvent solubility.
• the monomer (a3) is a monomer other than the monomer (a1) and the monomer (a2).
• the monomer (a3) is not particularly limited as long as it is copolymerizable with at least the monomer (a1).
• Examples of the monomer (a3) include aromatic vinyl monomers such as styrene, ⁇ -methylstyrene, p-methylstyrene, vinyltoluene, and chlorostyrene; Vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ⁇ -cyanoacrylate, dicyanovinylidene, and fumaronitrile; Monomers having a carboxyl group, such as crotonic acid, isocrotonic acid, cinnamic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, and glutaconic acid; Monomers having a sulfonic acid group, such as vinyl sulfonic acid and 2-acrylamide-2-methylpropanesulfonic acid; Polyfunctional monomers such as divinylbenzene, divinylnaphthalene, and divinyl ether; Examples of the monomer include vinyl monomers such as vinyl acetate and vinyl propionate
• the proportion of the structural unit (a3) in the resin is preferably 0 to 15% by mass, and more preferably 0 to 9.5% by mass, when the total of all structural units constituting the resin is taken as 100% by mass. If it is equal to or greater than the lower limit, the thixotropy of the resin when dissolved in a solvent is improved. If it is equal to or less than the upper limit, the thermal decomposition of the resin is improved. If it is within the above range, the resin has an appropriate degree of crosslinking, resulting in good thixotropy and thermal decomposition of the resin.
• Mercaptans having two or more SH groups act as chain transfer agents in the polymerization reaction.
• a mercaptan having two or more SH groups is used as a chain transfer agent in a polymerization reaction, so that the mercaptan having two or more SH groups becomes the starting point of polymerization, and a chemical structure (b1) derived from the mercaptan having two or more SH groups is introduced into the resin.
• Mercaptans having two or more SH groups are compounds that have two or more mercapto groups in a single molecule.
• Examples of mercaptans having two or more SH groups include mercaptans having a straight-chain or branched hydrocarbon skeleton, such as 1,2,3-trimercaptopropane, 2,2-bis(mercaptomethyl)-1-mercaptobutane, 1,2,3,4-tetramercaptobutane, and 2,2-bis(mercaptomethyl)-1,3-dimercaptopropane;
• Mercaptans having a 3-mercaptopropionate structure such as glycerin tris(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), and tetraethylene glycol bis(3-mercap
• mercaptans having a 3-mercaptopropionate structure and mercaptans having a thioglycolate structure are preferred, and trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), trimethylolpropane tris(thioglycolate), and pentaerythritol tetrakis(thioglycolate) are more preferred from the viewpoints of high reactivity and polymerization stability as a chain transfer agent and easy availability.
• the mercaptans having two or more SH groups may be used alone or in combination of two or more.
• the proportion of the structural unit (b1) in the resin is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 6 parts by mass, relative to 100 parts by mass of the total of all structural units constituting the resin. If it is equal to or greater than the lower limit, the thixotropy when the resin is dissolved in a solvent is improved. If it is equal to or less than the upper limit, the solvent solubility and thermal decomposition property of the resin are improved.
• Mercaptans having one SH group act as chain transfer agents in the polymerization reaction.
• a mercaptan having one SH group in addition to a mercaptan having two or more SH groups is used as a chain transfer agent in a polymerization reaction, so that the mercaptan having one SH group in addition to the mercaptan having two or more SH groups serves as the initiation point of polymerization, and a chemical structure (b2) derived from the mercaptan having one SH group is introduced into the resin.
• a mercaptan having one SH group is a compound having one mercapto group in a single molecule.
• mercaptans having one SH group include n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, thioglycolic acid, 3-mercaptopropionic acid, 2-mercaptoethanol, 2-ethylhexyl 3-mercaptopropionate, 2-ethylhexyl thioglycolate, isooctyl 3-mercaptopropionate, isooctyl thioglycolate, and 2-methoxybutyl 3-mercaptopropionate.
• n-Octyl mercaptan, n-dodecyl mercaptan, and t-dodecyl mercaptan are preferred from the viewpoints of high reactivity and polymerization stability as a chain transfer agent and easy availability.
• the mercaptans having one SH group may be used alone or in combination of two or more kinds.
• the proportion of the structural unit (b2) in the resin is preferably 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, and even more preferably 0 to 6 parts by mass, relative to 100 parts by mass of the total of all structural units constituting the resin. If it is equal to or less than the upper limit, the thermal decomposition property of the resin is further improved.
• the resin is preferably a sintering binder that is solid at room temperature.
• the amount of the resin added can be easily adjusted when preparing the paste composition described below, which makes it easy to adjust the viscosity range.
• the specific shape of the resin is not particularly limited, and examples thereof include solids in the form of powder, plates, crushed pieces, spheres, particles, granules, pellets, etc. Among these, solids in the form of powder, crushed pieces, spheres, particles, and granules are preferred because they are easy to handle when dissolved in a solvent.
• the resin of the present invention is preferably used as a binder for firing.
• binder for firing refers to a material that is used by printing the paste composition of the present invention on a substrate and then heating and firing in a high-temperature furnace for the purpose of forming the electronic circuit of the electronic device of the present invention, the electrode of the solar panel of the present invention, the inorganic sintered body of the present invention, or an electromagnetic wave shielding material having the inorganic sintered body of the present invention.
• the acid value of the resin (also referred to as solid acid value) is not particularly limited, but is preferably 0 to 50 mgKOH/g, more preferably 0 to 43 mgKOH/g, even more preferably 0 to 35 mgKOH/g, particularly preferably 0 to 15 mgKOH/g, and most preferably 1 to 19 mgKOH/g. If it is equal to or less than the upper limit, the thixotropy of the paste composition obtained using the resin is further improved.
• the upper and lower limits can be arbitrarily combined. For example, it may be 1 to 50 mgKOH/g, 1 to 43 mgKOH/g, 1 to 35 mgKOH/g, 1 to 15 mgKOH/g, or 0 to 19 mgKOH/g.
• the acid value of the resin is a value measured by neutralization titration using a potassium hydroxide (KOH) solution. The detailed measurement conditions are as described in the Examples section below.
• the mass average particle size of the resin is preferably greater than 100 ⁇ m and equal to or less than 1500 ⁇ m, more preferably 110 to 1000 ⁇ m, even more preferably 130 to 800 ⁇ m, particularly preferably 150 to 340 ⁇ m, and most preferably 170 to 280 ⁇ m. If it is greater than or equal to the lower limit, the risk of dust explosion is suppressed. If it is equal to or less than the upper limit, the solubility of the resin in a solvent is further improved.
• the upper and lower limits can be combined in any combination.
• it may be greater than 100 ⁇ m and equal to or less than 1000 ⁇ m, greater than 100 ⁇ m and equal to or less than 800 ⁇ m, greater than 100 ⁇ m and equal to or less than 340 ⁇ m, greater than 100 ⁇ m and equal to or less than 280 ⁇ m, 110 ⁇ m to 1000 ⁇ m or less, 110 ⁇ m to 800 ⁇ m or less, 110 ⁇ m to 340 ⁇ m or less, 110 ⁇ m to 280 ⁇ m or less, 130 ⁇ m to 1500 ⁇ m or less, 130 ⁇ m to 1000 ⁇ m or less, or 130 ⁇ m to 800 ⁇ m or less.
• the thickness may be 130 ⁇ m to 340 ⁇ m or less, 130 ⁇ m to 280 ⁇ m or less, 150 ⁇ m to 1500 ⁇ m or less, 150 ⁇ m to 1000 ⁇ m or less, 150 ⁇ m to 800 ⁇ m or less, 150 ⁇ m to 340 ⁇ m or less, 150 ⁇ m to 280 ⁇ m or less, 170 ⁇ m to 1500 ⁇ m or less, 170 ⁇ m to 1000 ⁇ m or less, 170 ⁇ m to 800 ⁇ m or less, 170 ⁇ m to 340 ⁇ m or less, or 170 ⁇ m to 280 ⁇ m or less.
• the mass average particle size of the resin can be calculated by shaking 20 g of the resin for 5 minutes and classifying it using a standard sieve.
• the thermal weight loss rate of the resin is preferably 95.0% or more, more preferably 99.0% or more, even more preferably 99.8% or more, and particularly preferably 99.9% or more.
• the higher the thermal weight loss rate the better the thermal decomposition property. If the thermal weight loss rate is equal to or higher than the lower limit, the amount of impurities in the inorganic sintered body obtained using the resin is suppressed.
• the upper limit of the thermal weight loss rate of the resin is 100%.
• the thermal weight loss rate of a resin is determined under the following measurement conditions. That is, using a differential thermal balance (TG-DTA), 5 mg of a measurement sample is heated in a nitrogen atmosphere from a starting temperature of 30° C. to 500° C.
• TG-DTA differential thermal balance
• Thermal weight loss rate (%) ⁇ (mass of measured sample (mg) ⁇ mass of residue (mg))/mass of measured sample (mg) ⁇ 100 (1)
• the ratio of the structural unit (b1) to all the structural units constituting the resin can be made 0.1 parts by mass or more relative to 100 parts by mass of the total of all the structural units constituting the resin, thereby making the value of the thermal weight loss rate small.
• the ratio of the structural unit (b1) to all the structural units constituting the resin can be made 20 parts by mass or less relative to 100 parts by mass of the total of all the structural units constituting the resin, thereby making the value of the thermal weight loss rate large.
• the weight average molecular weight (Mw) of the resin is preferably 10,000 to 1,000,000, more preferably 50,000 to 500,000, even more preferably 100,000 to 400,000, particularly preferably 150,000 to 350,000, and most preferably 200,000 to 300,000. If it is equal to or greater than the lower limit, the thixotropy of the paste composition obtained using the resin is further improved. If it is equal to or less than the upper limit, the solvent solubility of the resin is further improved.
• the water content of the resin is preferably 0.01 to 10 mass %, more preferably 0.02 to 8.0 mass %, further preferably 0.1 to 5.0 mass %, and particularly preferably 0.3 to 3.0 mass %, based on the total mass of the resin. If the water content is equal to or greater than the lower limit, the risk of dust explosion is suppressed. If the water content is equal to or less than the upper limit, the paste composition obtained using the resin has improved uniform film coating properties during screen printing. A specific method for measuring the water content of the resin is as described in the Examples section below.
• a resin solution having a resin concentration of 30% by mass obtained by dissolving a resin in terpineol that is, a resin solution containing 30% by mass of resin with respect to the total mass of the resin solution, preferably satisfies the following formula (2).
• ⁇ 1 and ⁇ 1000 are the viscosities (Pa ⁇ s) of the resin solution measured using a viscoelasticity measuring device under conditions of a cone plate of 1.0°/20 mm and a measurement temperature of 23°C
• ⁇ 1 is the viscosity (Pa ⁇ s) at a shear rate of 1 (1/s)
• ⁇ 1000 is the viscosity (Pa ⁇ s) at a shear rate of 1000 (1/s).
• the ⁇ 1/ ⁇ 1000 is preferably 1.5 or more, more preferably 2.0 or more, and even more preferably 2.3 or more. If it is equal to or more than the lower limit, the thixotropy when the resin is dissolved in a solvent is further improved. As a result, the printability when the paste composition obtained by using the resin is screen printed and the leveling property after printing are further improved.
• the upper limit of the ratio ⁇ 1/ ⁇ 1000 is not particularly limited, it is preferable that the ratio ⁇ 1/ ⁇ 1000 is 6.0 or less.
• the ratio ⁇ 1/ ⁇ 1000 may be 1.5 to 6.0, 2.0 to 6.0, or 2.3 to 6.0.
• the value of the ⁇ 1/ ⁇ 1000 can be increased by making the ratio of the structural unit (b1) to all structural units constituting the resin 0.1 parts by mass or more relative to 100 parts by mass of the total of all structural units constituting the resin. Also, the value of the ⁇ 1/ ⁇ 1000 can be decreased by making the ratio of the structural unit (b1) to all structural units constituting the resin 20 parts by mass or less relative to 100 parts by mass of the total of all structural units constituting the resin.
• the terpineol used in the viscosity measurement is a mixture of ⁇ -terpineol, which is the main component, ⁇ -terpineol, and ⁇ -terpineol.
• terpineol Commercially available terpineol can be used, and examples of the commercially available terpineol include "TERPINEOL PG" manufactured by Takasago International Corporation, “TERPINEOL C” manufactured by Nippon Terpene Chemical Co., Ltd., and “TERPINEOL” manufactured by Nippon Fragrance Pharmaceutical Co., Ltd.
• the resin may be a homopolymer or a copolymer of the monomer (a1), and is preferably a copolymer of the monomer (a1), the monomer (a2), and, if necessary, the monomer (a3).
• the resin may have any structure, such as a random copolymer, a graft copolymer, or a block copolymer.
• the resin can be produced by, for example, a commonly known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, etc., but is not limited to these polymerization methods. Among these, suspension polymerization is preferred because it can produce a resin in the form of spherical particles that are easy to handle.
• An example of a method for producing a resin by suspension polymerization will be described below.
• the method for producing a resin according to the present embodiment preferably includes, in the order described below, a suspension polymerization step, a first dehydration step, a washing step, a second dehydration step, and a drying step.
• the suspension polymerization step is a step of dispersing the above-mentioned monomer (a1) or a monomer mixture (M1) containing the monomer (a1) and the monomer (a2) and, if necessary, the monomer (a3) in water, and carrying out suspension polymerization in the presence of a mercaptan having two or more SH groups and, if necessary, a mercaptan having one SH group, to obtain a resin.
• the content of the monomer (a1) relative to the total mass of the monomer mixture (M1) is preferably 70 to 100 mass%, more preferably 90 to 100 mass%, further preferably 95 to 100 mass%, particularly preferably 97 to 100 mass%, and most preferably 99 to 100 mass%.
• the content of the monomer (a2) is preferably 0 to 20 mass%, more preferably 0.01 to 20 mass%, even more preferably 0.1 to 10 mass%, particularly preferably 0.1 to 6 mass%, particularly preferably 0.1 to 5 mass%, and most preferably 0.3 to 5 mass%.
• the content of the monomer (a3) relative to the total mass of the mixture (M2) is preferably from 0 to 15 mass%, more preferably from 0 to 9.5 mass%.
• the suspension polymerization method a known method can be adopted, and an example thereof includes a method in which the monomer (a1) or the monomer mixture (M1) is polymerized in a suspended state in water in the presence of a polymerization auxiliary in a vessel having a polymerization temperature control function and a stirring function.
• the polymerization aid include a chain transfer agent, a radical polymerization initiator, a dispersant, and a dispersion aid.
• the above-mentioned mercaptan having at least two or more SH groups is used as the chain transfer agent.
• a resin having the chemical structure (b1) can be obtained by using a polymerization aid, specifically a mercaptan having two or more SH groups as a chain transfer agent.
• a resin having the chemical structure (b2) can be obtained by using a mercaptan having one SH group in addition to a mercaptan having two or more SH groups as a chain transfer agent.
• the above-mentioned mercaptan having two or more SH groups is used.
• a chain transfer agent in addition to the mercaptan having two or more SH groups, the above-mentioned mercaptan having one SH group may be used in combination.
• a chain transfer agent other than the mercaptan having one SH group and the mercaptan having two or more SH groups may be used in combination.
• Other chain transfer agents include, for example, hydrogen, diphenyl disulfide, dibenzyl disulfide, ⁇ -methylstyrene dimer, terpenoids, and cobalt chain transfer agents. The other chain transfer agents may be used alone or in combination of two or more.
• the amount of the mercaptan having two or more SH groups used is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 6 parts by mass, based on 100 parts by mass of the total of all the monomers used in the suspension polymerization.
• the amount of the mercaptan having one SH group used is preferably 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, and even more preferably 0 to 6 parts by mass, based on 100 parts by mass of the total of all the monomers used in the suspension polymerization.
• the radical polymerization initiator is not particularly limited, but examples thereof include organic peroxides and azo compounds.
• organic peroxides include t-butyl peroxypivalate, o-methylbenzoyl peroxide, bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, cyclohexanone peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, lauroyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butylperoxy-2-ethylhexanoate, and 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate.
• Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile).
• benzoyl peroxide lauroyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(2,4-dimethylvaleronitrile) are preferred.
• the radical polymerization initiator may be used alone or in combination of two or more kinds.
• the amount of the radical polymerization initiator used is not particularly limited, but from the viewpoint of improving the polymerization rate of the monomers, it is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the total of all the monomers used in the suspension polymerization.
• the dispersant is not particularly limited, but examples thereof include surfactants that stably disperse monomers in water. Specific examples thereof include copolymers of sodium methacrylate and methacrylic acid, polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, and hydroxypropyl cellulose.
• the dispersant may be used alone or in combination of two or more kinds.
• the dispersion aid is not particularly limited, but examples thereof include sodium sulfate, sodium carbonate, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium chloride, calcium acetate, magnesium sulfate, and manganese sulfate.
• the dispersion aid may be used alone or in combination of two or more kinds.
• the resin obtained by suspension polymerization is in the form of a slurry.
• the resin By dehydrating the slurry, the resin is obtained in the form of bead-like resin particles that are usually nearly spherical.
• Examples of the dehydration step include a first dehydration step in which the slurry after the suspension polymerization is dehydrated with a dehydrator or the like to separate the resin from the reaction liquid, and a second dehydration step in which the resin after the washing step described below is dehydrated with a dehydrator or the like to separate the resin in the form of resin particles from the washing liquid.
• dehydrators can be used for each dehydration process, such as dehydrators that use a filtering mechanism such as a filter cloth, centrifugal dehydrators, and dehydrators that use a porous belt to suck and remove water.
• One dehydrator may be used, or two of the same model may be used for each dehydration process, or multiple different models of dehydrators may be used.
• a model that suits the purpose can be selected from the standpoints of product quality, capital investment costs, productivity, operating costs, etc.
• a dedicated dehydrator may be used for each dehydration process.
• the washing step is a step of washing the resin obtained in the first dehydration step.
• the washing step increases the purity of the resin.
• the washing method for the resin include a method in which a washing liquid is added to the resin particles dehydrated in the first dehydration step, the particles are reslurried and stirred and mixed, and a method in which the first dehydration step is performed in a dehydrator having a washing function, and then the washing liquid is added to wash the resin.
• the resin may be washed by combining these washing methods.
• the type and amount of the cleaning liquid may be selected so as to achieve the purpose of the cleaning step.
• the cleaning liquid include water such as ion-exchanged water, distilled water, and purified water; an aqueous solution in which a sodium salt is dissolved; and alcohol such as methanol.
• the cleaning solution may be used alone or in combination of two or more kinds.
• the drying step is a step of drying the resin particles (resin particles) obtained in the second dehydration step. Water remains on the surface of the resin particles after the second dehydration step. When the inside of the resin is close to being saturated with water, it is preferable to dry the resin in order to further reduce the water content of the resin from the viewpoint of improving the purity of the resin.
• dryers can be used to dry the resin, including, for example, a dryer that dries by heating under reduced pressure, a dryer that uses heated air to air-transport resin particles through a pipe while drying them at the same time, and a dryer that blows heated air from below a porous plate to dry the resin particles above while causing them to flow.
• the drying step is preferably carried out so that the water content of the resin particles after the drying step is 0.01 to 10% by mass with respect to the total mass of the resin.
• the resin of the present embodiment described above is solid and has the structural unit (a1), and therefore has excellent solvent solubility and thermal decomposition properties.
• the resin has the chemical structure (b1) in addition to the structural unit (a1), and therefore has high thixotropy.
• the reason why the resin has the chemical structure (b1) and thus has high thixotropy is not clear, but is thought to be as follows.
• the resin has many branched structures rather than a linear structure. Generally, the more the amount of resin in the resin solution, the more thixotropic it is. However, when the resin has a linear structure, it is difficult to increase the amount of high molecular weight resin added because thickening proceeds.
• the chain length is shorter than that of a linear structure, so thickening can be suppressed and the amount of high molecular weight resin added can be increased. Therefore, it is considered that the resin has high thixotropy by having the chemical structure (b1).
• the resin further contains the structural unit (a2) in addition to the structural unit (a1) and the chemical structure (b1), the thixotropy is improved when the binder resin is dissolved in a solvent. Furthermore, when the resin further has the chemical structure (b2) in addition to the structural unit (a1) and the chemical structure (b1), thickening of the resin when dissolved in a solvent is suppressed.
• the resin can be used, for example, as a raw material for internal electrode layers or external electrode layers of multilayer electronic components such as electronic devices, solar panels, and multilayer ceramic capacitors, and as a paste raw material for solar cell electrodes.
• the paste composition of the present embodiment contains the above-mentioned resin of the present invention, a metal or inorganic compound, and an organic solvent.
• the paste composition may further contain, as necessary, components other than the resin, the metal or inorganic compound, and the organic solvent (hereinafter also referred to as "optional components") as long as the effects of the present invention are not impaired.
• the resin content is preferably 0.1 to 20% by mass, and more preferably 1 to 10% by mass, based on the total mass of the paste composition. If it is equal to or greater than the lower limit, the moldability of the paste composition is improved. If it is equal to or less than the upper limit, the solids concentration of the components other than the resin in the paste composition can be increased.
• the metal or inorganic compound is not particularly limited, but examples thereof include oxides such as alumina, zirconia, titanium oxide, barium titanate, calcium oxide, etc.; nitrides such as alumina nitride, silicon nitride, boron nitride, etc.; metals such as copper, silver, nickel, etc.; silica-based powders such as low-melting point glass powder; carbon-based powders such as carbon black, etc.; and various phosphors.
• the metal or inorganic compound may be used alone or in combination of two or more kinds.
• the content of the metal or inorganic compound is preferably 40 to 90 mass% based on the total mass of the paste composition. If it is equal to or greater than the lower limit, the molding efficiency of the paste composition is improved. If it is equal to or less than the upper limit, the moldability of the paste composition is improved.
• the organic solvent is not particularly limited, but is preferably an organic solvent having a boiling point of 180° C. or higher, and more preferably an organic solvent having a boiling point of 200° C. or higher.
• the upper limit of the boiling point of the organic solvent is not particularly limited, but the boiling point of the organic solvent is preferably not more than 400° C.
• the boiling point of the organic solvent may be 180 to 400° C., or 200 to 400° C.
• organic solvents having a boiling point of 180° C. or higher include ⁇ , ⁇ , ⁇ -terpineol, terpineol acetate, dihydroterpineol, dihydroterpineol acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monoisobutyl ether, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and isophorone.
• benzyl alcohol 1-octanol, 1-nonaol, 2-ethyl-1-hexanol, 1-decanol, 1-undecanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, texanol, butyl lactate, dioctyl phthalate, dioctyl adipate, phenylpropylene glycol, cresol, dimethyl sulfoxide, and N-methylpyrrolidone.
• the organic solvent may be used alone or in combination of two or more kinds.
• the content of the organic solvent is preferably 9.9 to 50% by mass based on the total mass of the paste composition. If it is equal to or greater than the lower limit, the moldability of the paste composition is improved. If it is equal to or less than the upper limit, the solids concentration of the paste composition is improved.
• optional components include plasticizers, dispersing agents, antifoaming agents, and resins other than the resin of the present invention.
• the optional components may be used alone or in combination of two or more.
• the paste composition can be obtained by mixing, for example, a resin, an inorganic compound, an organic solvent, and, if necessary, optional components.
• the paste composition of the present embodiment described above contains the resin of the present invention, and therefore has high thixotropy, and is excellent in both printability when the paste composition is screen printed and in leveling property after printing.
• the paste composition of the present embodiment has excellent printability in screen printing, it is preferable to apply screen printing when forming a pattern on a substrate using the paste composition of the present embodiment, but a method other than screen printing may be applied.
• a method other than screen printing may be applied.
• a dip coating method or a dispense coating method can be applied, and when the viscosity is low, a doctor blade coating method or a cast coating method can be applied.
• the substrate onto which the paste composition is printed or applied is not particularly limited, but examples thereof include ceramic substrates and capacitors.
• the inorganic sintered body of the present embodiment is obtained by firing the above-mentioned paste composition of the present invention.
• the firing method is not particularly limited, but may be, for example, a method in which a substrate on which the paste composition is printed or applied is placed in a high-temperature atmosphere. During the firing process, organic substances such as resins contained in the paste composition are decomposed and removed, and metals or inorganic compounds contained in the paste composition are melted and sintered to obtain an inorganic sintered body.
• the firing temperature can be appropriately determined depending on the melting temperature of the substrate, the inorganic powder, and the type of organic substance contained in the paste composition, but is usually about 200 to 1500°C, and preferably 300 to 1000°C.
• the electronic device of the present invention preferably has the inorganic sintered body.
• the electronic device include semiconductors such as logic circuits, memory circuits, and analog circuits, lithium ion batteries, capacitors, printed circuits, and current collecting circuits of solar panels.
• the solar panel of the present invention preferably has an inorganic sintered body.
• ⁇ Evaluation of thixotropy> In the same manner as in the evaluation of solvent solubility, a resin solution containing 30% by mass of resin was prepared.
• the viscosity (Pa ⁇ s) of the resin solution was measured using a viscoelasticity measuring device (manufactured by Thermo Fisher Scientific, product name "HAAKE MARS") under the conditions of a cone plate of 1.0°/20 mm and a measurement temperature of 23° C.
• the viscosity (Pa ⁇ s) of the resin solution at a shear rate of 1 (1/s) was defined as ⁇ 1
• the viscosity (Pa ⁇ s) at a shear rate of 1000 (1/s) was defined as ⁇ 1000
• the solvent solubility was evaluated according to the following evaluation criteria.
• a higher value of ⁇ 1/ ⁇ 1000 means better thixotropy.
• Example 1 In a polymerization apparatus equipped with a stirrer, a cooling tube, and a thermometer, 97.4 parts of i-butyl methacrylate, 2.6 parts of trimethylolpropane triacrylate were uniformly dissolved in a monomer mixture, 1.9 parts of pentaerythritol tetrakis (thioglycolate), 1.9 parts of n-octyl mercaptan, and 1.9 parts of n-dodecyl mercaptan were added, and the mixture was stirred and mixed until it was uniform. Furthermore, 0.3 parts of 2,2'-azobis (2-methylbutyronitrile) was added, and the mixture was stirred and mixed until it was uniform.
• the resin (A11) obtained in Comparative Example 3 had a ratio Mw/Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) outside the range specified in the present application, and therefore had poor thixotropy.
• the resin of the present invention has excellent solvent solubility, thermal decomposition properties, and high thixotropy, and therefore has excellent screen printability and leveling properties after printing.
• the resin of the present invention can be used, for example, as a raw material for internal electrode layers or external electrodes of multilayer electronic components such as electronic devices, solar panels, and multilayer ceramic capacitors, and as a paste raw material for solar cell electrodes, and is therefore of great industrial importance.

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• 2024
  • 2024-03-05 JP JP2025510113A patent/JPWO2024203009A1/ja active Pending
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