Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
  • B32B15/092—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
• • 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
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives
• • 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
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/15—Heterocyclic compounds having oxygen in the ring
  • C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
  • C08K5/1515—Three-membered rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/22—Secondary treatment of printed circuits
  • H05K3/28—Applying non-metallic protective coatings

Definitions

• the present invention relates to a curable composition, a cured product, an overcoat film, a flexible wiring board, and a method for manufacturing the same.
• the flexible wiring board is coated with an overcoat film to protect the surface.
• This overcoat film is formed by applying a curable composition to the surface of a flexible substrate on which wiring is formed by a printing method or the like and curing it.
• the curable composition for forming the overcoat film causes the flexible wiring board to warp as compared with the conventional one. Difficult performance is required. If the flexible wiring board is warped, the alignment accuracy of the mounting position of the IC chip is adversely affected in the mounting process of mounting the IC chip on the flexible wiring board, so that the yield in the manufacturing process may be lowered.
• Patent Document 1 contains polyurethane obtained by reacting a diisocyanate compound with a plurality of types of diol compounds. Curable compositions are disclosed. By using the curable composition disclosed in Patent Document 1, it is possible to obtain an overcoat film for a flexible wiring board which is excellent in low warpage, flexibility, long-term insulation reliability, and wire breakage suppression property.
• the distance (pitch) between the wires of the flexible wiring board will be further narrowed (for example, 20 ⁇ m or less). Therefore, the low warpage of the flexible wiring board and the flexible wiring board Further improvement in wire breakage suppression was desired.
• the present invention describes the performance that makes it difficult for the flexible wiring board to warp (hereinafter, also referred to as "low warpage") and the performance that suppresses the disconnection of the wiring of the flexible wiring board (hereinafter, “the disconnection suppressing property of the wiring”). It is an object of the present invention to provide an excellent curable composition (which may be). Another object of the present invention is to provide a cured product and an overcoat film having excellent low warpage property and wire disconnection suppressing property. Another object of the present invention is to provide a flexible wiring board having low warpage and excellent ability to suppress disconnection of wiring and a method for manufacturing the same.
• One aspect of the present invention is as follows [1] to [15]. [1] It is used in the production of a flexible wiring board in which a portion of the surface of a flexible substrate on which wiring is formed is coated with an overcoat film, and the overcoat film is formed by forming a cured product.
• a curable composition having a tensile elastic modulus of 600 MPa or more and 2000 MPa or less and a tensile yield strength of 17 MPa or more.
• the polymer (component c) comprising at least one group selected from a carboxy group, an isocyanato group, a hydroxy group, an amide group, and a cyclic acid anhydride group as the functional group [2] to [4].
• the polymer (component c) has a structural unit represented by the following formula (1) in the molecule, m pieces of R 1 in formula (1) are each independently 1, 2 It represents a 1,2-phenylene group having a-phenylene group or a substituent, and m R 2 independently represent an alkylene group having 3 or more and 10 or less carbon atoms, and R 3 has 3 or more and 10 or less carbon atoms.
• the curable composition according to any one of [2] to [5], which represents an alkylene group and m is an integer of 1 or more and 50 or less.
• the ratio of the content of the solvent (component b) to the total amount of the epoxy compound (component a), the solvent (component b) and the polymer (component c) is 25% by mass or more and 75% by mass or less. [2] to [8], wherein the ratio of the content of the epoxy compound (component a) to the total amount of the epoxy compound (component a) and the polymer (component c) is 1% by mass or more and 60% by mass or less.
• the curable composition according to any one item.
• the ratio of the content of the solvent (component b) to the total amount of the epoxy compound (component a), the solvent (component b), the polymer (component c) and the fine particles (component d) is 25% by mass.
• the ratio of the content of the fine particles (component d) is 0.1% by mass or more and 60% by mass or less.
• the curable composition according to the present invention is excellent in the ability to prevent warping of the flexible wiring board and the ability to suppress disconnection of the wiring of the flexible wiring board.
• the cured product, the overcoat film, and the flexible wiring board according to the present invention are excellent in low warpage property and wire disconnection suppressing property.
• the method for manufacturing a flexible wiring board according to the present invention can manufacture a flexible wiring board having excellent low warpage property and wire disconnection suppressing property.
• the present inventors have obtained an overcoat obtained by curing the curable composition by using a curable composition capable of producing a cured product having specific physical properties.
• a curable composition capable of producing a cured product having specific physical properties We have found that the flexible wiring board having a coated film is less likely to warp and the wiring of the flexible wiring board is less likely to be broken, and have completed the present invention.
• the curable composition of the present embodiment is used for manufacturing a flexible wiring board in which a portion of the surface of a flexible substrate on which wiring is formed is coated with an overcoat film. , An overcoat film is formed by forming a cured product.
• the curable composition of the present embodiment has a tensile elastic modulus of 600 MPa or more and 2000 MPa or less and a tensile yield strength of 17 MPa or more.
• the cured product having the above-mentioned tensile elastic modulus and tensile yield strength, the overcoat film containing the cured product, and the flexible wiring board having the overcoat film are excellent in low warpage and wire breakage suppressing property. There is. That is, the curable composition of the present embodiment is excellent in the performance of preventing the flexible wiring board from warping and the performance of suppressing the disconnection of the wiring of the flexible wiring board.
• the tensile elastic modulus of the cured product obtained by curing the curable composition of the present embodiment needs to be 600 MPa or more and 2000 MPa or less as described above, but is preferably 700 MPa or more and 1800 MPa or less. Further, the tensile yield strength of the cured product obtained by curing the curable composition of the present embodiment needs to be 17 MPa or more as described above, but is preferably 21 MPa or more.
• the tensile yield strength of the cured product obtained by curing the curable composition of the present embodiment is preferably 50 MPa or less, more preferably 30 MPa or less, from the viewpoint of ease of material design.
• the tensile elastic modulus and tensile yield strength of the cured product in the present invention were measured by performing a tensile test under the following test conditions on a test piece produced by the following method.
• the curable composition is applied in a film form on the surface of the substrate and cured by heating at a temperature of 120 ° C. for 120 minutes to prepare a strip-shaped test piece having a width of 1 cm, a length of 5 cm, and a thickness of 50 ⁇ m. ..
• the thickness of the test piece is accurately measured using a micrometer or the like.
• the curable composition of the present embodiment contains an epoxy compound (component a) having two or more epoxy groups in one molecule, a solvent (component b), and an epoxy group contained in the epoxy compound (component a). It is preferable to contain a polymer (component c) having a functional group having the reactivity of the above.
• Epoxy compound having two or more epoxy groups in one molecule (component a)
• the epoxy compound (component a) which is one of the essential components of the curable composition of the present embodiment, reacts with the functional group (for example, carboxy group) contained in the polymer (component c) and acts as a curing agent in the curable composition. It works.
• the type of the epoxy compound (component a) is not particularly limited as long as it is a compound having two or more epoxy groups in one molecule, and examples thereof include a novolak type epoxy resin obtained by epoxidizing a novolak resin.
• Specific examples of the novolak type epoxy resin include phenol novolac type epoxy resin and orthocresol novolac type epoxy resin.
• the novolak resin includes phenols such as phenol, cresol, xylenol, resorcin, and catechol, and / or naphthols such as ⁇ -naphthol, ⁇ -naphthol, and dihydroxynaphthalene, and formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde. It is a resin obtained by condensing or co-condensing a compound having an aldehyde group such as the above under an acidic catalyst.
• examples of the epoxy compound (component a) include diglycidyl ethers of phenols and glycidyl ethers of alcohols.
• examples of the above-mentioned phenols include bisphenol A, bisphenol F, bisphenol S, alkyl-substituted or unsubstituted biphenols, and stillben-based phenols. That is, the diglycidyl ethers of these phenols are bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, biphenyl type epoxy compound, and stillben type epoxy compound.
• examples of the alcohol include butanediol, polyethylene glycol, polypropylene glycol and the like.
• examples of the epoxy compound (component a) include glycidyl ester-type epoxy resins of carboxylic acids such as orthophthalic acid, isophthalic acid, and tetrahydrophthalic acid, and aniline, bis (4-aminophenyl) methane, and isocyanuric acid.
• a glycidyl-type or methylglycidyl-type epoxy resin which is a compound in which active hydrogen bonded to a nitrogen atom is replaced with a glycidyl group, and active hydrogen and a phenolic hydroxy group bonded to a nitrogen atom possessed by aminophenols such as p-aminophenol.
• examples thereof include glycidyl-type or methylglycidyl-type epoxy resins, which are compounds in which the active hydrogen contained in the above is replaced with a glycidyl group.
• epoxy compound (component a) for example, vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 2- (3,4-epoxy) cyclohexyl-5,5-
• examples thereof include alicyclic epoxy resins such as spiro (3,4-epoxy) cyclohexane-m-dioxane. These alicyclic epoxy resins are obtained by epoxidizing the olefin bonds of an alicyclic hydrocarbon compound having an olefin bond in the molecule.
• examples of the epoxy compound (component a) include glycidyl ether of paraxylylene and / or metaxylylene-modified phenol resin, glycidyl ether of terpene-modified phenol resin, glycidyl ether of dicyclopentadiene-modified phenol resin, and glycidyl of cyclopentadiene-modified phenol resin.
• examples thereof include ethers, glycidyl ethers of polycyclic aromatic ring-modified phenolic resins, and glycidyl ethers of naphthalene ring-containing phenolic resins.
• examples of the epoxy compound (component a) include a halogenated phenol novolac type epoxy resin, a hydroquinone type epoxy resin, a trimethylolpropane type epoxy resin, and a linear aliphatic epoxy resin (a linear fat having an olefin bond in the molecule).
• a halogenated phenol novolac type epoxy resin a hydroquinone type epoxy resin, a trimethylolpropane type epoxy resin, and a linear aliphatic epoxy resin (a linear fat having an olefin bond in the molecule).
• an epoxidized product of an aralkyl type phenol resin such as a phenol aralkyl resin or a naphthol aralkyl resin, a sulfur atom-containing epoxy resin, or a tricyclo [5.2.1.0 2,6 ] Diglycidyl ether of decandimethanol and epoxy resin having an adamantan structure can be mentioned.
• epoxy resins having an adamantane structure examples include 1,3-bis (1-adamantyl) -4,6-bis (glycidyloyl) benzene, 1- [2', 4'-bis (glycidiroyl) phenyl] adamantane, 1 , 3-Bis (4'-glycidyl phenyl) adamantane, 1,3-bis [2', 4'-bis (glycidyl phenyl) phenyl] adamantane and the like.
• One of these epoxy compounds (component a) may be used alone, or two or more thereof may be used in combination.
• an epoxy compound having two or more epoxy groups in one molecule and having at least one of an aromatic ring structure and an alicyclic structure is preferable.
• the aromatic ring structure include a benzene ring
• examples of the alicyclic structure include a tricyclodecane structure.
• one molecule has two or more epoxy groups, and has an aromatic ring structure and a fat.
• the epoxy compounds having at least one of the ring structures a compound having two or more epoxy groups in one molecule and having a tricyclodecane structure and an aromatic ring structure is preferable.
• Specific examples of the compound having two or more epoxy groups in one molecule and having a tricyclodecane structure and an aromatic ring structure include glycidyl ether of a dicyclopentadiene-modified phenol resin (that is, two or more in one molecule).
• the epoxy compound having two or more epoxy groups in one molecule and having at least one of an aromatic ring structure and an alicyclic structure.
• a compound having two or more epoxy groups in one molecule and having an amino group and an aromatic ring structure is preferable.
• glycidyl is an active hydrogen bonded to a nitrogen atom of aniline and bis (4-aminophenyl) methane.
• Glycidyl-type or methylglycidyl-type epoxy resin which is a compound substituted with a group
• glycidyl which is a compound in which active hydrogen bonded to a nitrogen atom of aminophenols and active hydrogen of a phenolic hydroxy group are each substituted with a glycidyl group.
• Examples thereof include type or methylglycidyl type epoxy resins and compounds represented by the following formula (6). Among these, the compound represented by the following formula (6) is particularly preferable.
• the ratio of the content of the epoxy compound (component a) to the total amount of the epoxy compound (component a) and the polymer (component c) in the curable composition of the present embodiment is 1% by mass or more and 60% by mass or less. Is more preferable, and it is more preferably 2% by mass or more and 50% by mass or less, and further preferably 3% by mass or more and 40% by mass or less. That is, the ratio of the content of the polymer (component c) to the total amount of the epoxy compound (component a) and the polymer (component c) in the curable composition of the present embodiment is 40% by mass or more and 99% by mass or less. It is more preferable, it is more preferably 50% by mass or more and 98% by mass or less, and further preferably 60% by mass or more and 97% by mass or less.
• the overcoat film described later is coated. It is possible to balance the low warpage of the flexible wiring board, which will be described later, with the ability to suppress disconnection of the wiring.
• solvent (component b) which is one of the essential components of the curable composition of the present embodiment, is not particularly limited as long as the epoxy compound (component a) and the polymer (component c) can be dissolved.
• ether solvents such as glycol dimethyl ether and tripropylene glycol dimethyl ether.
• the solvent (component b) includes ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, and dipropylene glycol monoethyl ether acetate.
• Diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, ⁇ -butyrolactone and other ester solvents can be mentioned.
• examples of the solvent (component b) include a hydrocarbon solvent such as decahydronaphthalene and a ketone solvent such as cyclohexanone.
• a hydrocarbon solvent such as decahydronaphthalene
• a ketone solvent such as cyclohexanone.
• One of these solvents may be used alone, or two or more of these solvents may be used in combination.
• ⁇ -butyrolactone, diethylene glycol diethyl ether, diethylene glycol monoethyl ether acetate and diethylene glycol monomethyl ether acetate are preferable, and ⁇ -butyrolactone and diethylene glycol are preferable in consideration of the balance between printability during screen printing and solvent volatility. More preferably, monoethyl ether acetate and diethylene glycol diethyl ether are a single solvent of ⁇ -butyrolactone, a mixed solvent of ⁇ -butyrolactone and diethylene glycol monoethyl ether acetate, a mixed solvent of ⁇ -butyrolactone and diethylene glycol diethyl ether, and ⁇ -. A three-kind mixed solvent of butyrolactone, diethylene glycol monoethyl ether acetate, and diethylene glycol diethyl ether is more preferable.
• the content of the solvent (component b) in the curable composition of the present embodiment is the total mass of the curable composition of the present embodiment, that is, the epoxy compound (component a), the solvent (component b) and the polymer (component c). It is preferably 25% by mass or more and 75% by mass or less, and more preferably 35% by mass or more and 65% by mass or less with respect to the total amount of.
• the viscosity of the curable composition is in the screen printing method.
• the viscosity is good for printing, and the spread of the curable composition after screen printing due to bleeding is not so large.
• the phenomenon that the printed area of the curable composition actually printed is larger than the portion to which the curable composition is to be applied (that is, the shape of the printing plate) is less likely to occur, which is preferable.
• the type of the polymer (component c) is not particularly limited as long as it is a polymer having a functional group reactive with the epoxy group of the epoxy compound (component a).
• Examples of the functional group having a reactivity with the epoxy group of the epoxy compound (component a) include a carboxy group, an isocyanato group, a hydroxy group, an amide group and a cyclic acid anhydride group.
• the polymer (component c) may contain one of these functional groups, or may contain two or more of these functional groups.
• the cyclic acid anhydride group refers to an acid anhydride group formed by dehydration of two carboxy groups in the molecule when the acid anhydride group forms a part of the ring structure.
• a carboxy group, an isocyanato group, an amide group, and a cyclic acid anhydride group are preferable in consideration of the reactivity of the epoxy compound (component a) with the epoxy group. Further, considering the balance between the storage stability of the polymer (component c) and the reactivity of the epoxy compound (component a) with the epoxy group, a carboxy group and a cyclic acid anhydride group are more preferable, and a carboxy group is further preferable. ..
• the polymer (component c) is preferably a polymer having a carbamate group (-NHCOO-), that is, polyurethane.
• the concentration of the carbamate group in the polymer (component c) is preferably 1.00 mmol / g or more and 2.90 mmol / g or less, and more preferably 1.50 mmol / g or more and 2.30 mmol / g or less. It is more preferably 1.67 mmol / g or more and 2.13 mmol / g or less.
• the aromatic ring concentration of the polymer (component c) is preferably 0.1 mmol / g or more and 6.5 mmol / g or less, preferably 2.0 mmol. It is more preferably / g or more and 4.5 mmol / g or less, and further preferably 2.5 mmol / g or more and 3.7 mmol / g or less.
• aromatic ring concentration will be described in detail in later examples.
• the polymer (component c) preferably has a structural unit represented by the following formula (1) in the molecule.
• the m R 1 in formula (1) represents a 1,2-phenylene group having each independently 1,2-phenylene group or a substituted group
• the m R 2 are each independently carbon It represents an alkylene group having a number of 3 or more and 10 or less
• R 3 represents an alkylene group having 3 or more carbon atoms and 10 or less carbon atoms
• m is an integer of 1 or more and 50 or less.
• m number of R 1 is independently an 1,2-phenylene or 1,2-phenylene group having a substituent
• a total of m R 1 is a the same group it may be, to the other part in the m part of R 1 is the same group may be another group, means that all of the m R 1 may be different groups To do.
• the structural unit represented by the formula (1) can be derived from the raw material compound represented by the following formula (2). R 1 , R 2 , R 3 , and m in the following formula (2) are the same as in the case of the formula (1).
• R 1 include 1,2-phenylene group, 3-methyl-1,2-phenylene group, 4-methyl-1,2-phenylene group, 3-ethyl-1,2-phenylene group, 4-.
• Ethyl-1,2-phenylene group, 3-chloro-1,2-phenylene group, 4-chloro-1,2-phenylene group, 3-bromo-1,2-phenylene group, 4-bromo-1,2- Examples include a phenylene group. Among these, a 1,2-phenylene group, a 3-methyl-1,2-phenylene group, and a 4-methyl-1,2-phenylene group are more preferable, and a 1,2-phenylene group is even more preferable.
• the formula (1) and the m R 2 in the formula (2) is an alkylene group having 3 to 10 carbon atoms independently, specific examples of the alkylene group having 3 to 10 carbon atoms , 1,3-propylene group, 1,2-propylene group, 1,4-butylene group, 2,2-dimethylpropylene group, 1,5-pentylene group, 1,6-hexylene group, 3-methyl-1, Examples thereof include an alkylene group such as a 5-pentylene group, a 1,8-octylene group, a 1,9-nonylene group and a 2-methyl-1,8-octylene group.
• alkylene groups 1,3-propylene group, 1,4-butylene group, 1,5-pentylene group, 1,6-hexylene group, 1,8-octylene group, 1,9-nonylene group and the like.
• branched chain alkylene groups such as 2,2-dimethylpropylene group, 3-methyl-1,5-pentylene group are more preferable, 1,5-pentylene group, 1,6-hexylene group, 1 , 8-octylene group, 1,9-nonylene group and other linear alkylene groups are more preferred.
• R 3 in the above formulas (1) and (2) represents an alkylene group having 3 or more and 10 or less carbon atoms, and specific examples of alkylene groups having 3 or more and 10 or less carbon atoms and preferable examples among them are described. , The same as in the case of R 2 above. m is preferably an integer of 1 or more and 30 or less, and more preferably an integer of 1 or more and 10 or less.
• the molecular weight of the polymer (component c) is not particularly limited, but considering the ease of adjusting the viscosity of the curable composition of the present embodiment, the number average molecular weight of the polymer (component c) is 5000 or more and 50,000 or less. It is preferably 10,000 or more and 40,000 or less, and further preferably 10,000 or more and 30,000 or less.
• the "number average molecular weight” referred to here is a polystyrene-equivalent number average molecular weight measured by gel permeation chromatography (hereinafter referred to as "GPC").
• GPC gel permeation chromatography
• the acid value of the polymer (component c) is not particularly limited, but when the functional group is a carboxy group or a cyclic acid anhydride group, it is preferably 5 mgKOH / g or more and 60 mgKOH / g or less, and 10 mgKOH. It is more preferably / g or more and 40 mgKOH / g or less, and further preferably 10 mgKOH / g or more and 30 mgKOH / g or less.
• the polymer (component c) has sufficient reactivity with the epoxy group of the epoxy compound (component a). Therefore, the heat resistance of the cured product of the curable composition does not easily decrease, and the cured product of the curable composition does not become too hard and brittle. In addition, it becomes easy to balance the solvent resistance of the overcoat film described later with the warp of the flexible wiring board described later.
• the acid value of the polymer (component c) is the value of the acid value measured by the potentiometric titration method specified in JIS K0070.
• the ratio of the total amount of the structural units represented by the formula (1) to the total amount of the polymer (component c) is preferably 7% by mass or more and 30% by mass or less, and is 7% by mass or more and 28% by mass or less. It is more preferable that the content is 8% by mass or more and 27% by mass or less.
• the flexible wiring board of the present embodiment described later has low warpage property and wiring disconnection suppression property. It becomes easy to balance with.
• polymer (component c) examples include polyurethane having a structural unit represented by the following formula (3) and a structural unit represented by the following formula (4) in the molecule.
• Polyurethane having a structural unit represented by the following formula (4) in its molecule has a carboxy group as a functional group having reactivity with the epoxy group of the epoxy compound (component a).
• R 1 , R 2 , R 3 , and m in the formula (3) are the same as in the case of the formula (1).
• R 4 in the formula (3) represents an organic residue derived from a diisocyanate compound having two isocyanato groups in one molecule.
• R 5 in the formula (4) represents an organic residue derived from a diisocyanate compound having two isocyanato groups in one molecule, and R 6 represents a methyl group or an ethyl group.
• R 4 in the formula (3) and R 5 in the formula (4) indicate organic residues derived from the diisocyanate compound, and the specifics of the diisocyanate compound in which two isocyanato groups are bonded to R 4 or R 5 Examples include isophorone diisocyanate, methylene bis (4-cyclohexamethylene), 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, diphenylmethane-4,4'-diisocyanate, 1, 3-xylylene diisocyanate, 1,4-xylylene diisocyanate, biuret of isophorone diisocyanate, biuret of hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexanemethylene diisocyanate, norbornan Diisocyanate and the like can be mentioned.
• the diisocyanate compounds include isophorone diisocyanate, methylene bis (4-cyclohexylisocyanate), 1,3-bis (isocyanatomethyl) cyclohexane, and 1,4-bis.
• 1,3-bis (isocyanatomethyl) cyclohexane, 1,4- Bis (isocyanatomethyl) cyclohexane is preferred.
• One of these diisocyanate compounds may be used alone, or two or more thereof may be used in combination.
• the portion derived from monocarboxydiol containing R 6 in the formula (4) is a group derived from 2,2-dimethylol alkanoic acid. That is, 2,2-dimethylol alkanoic acid may be used as one of the diols as a raw material of polyurethane which is a polymer (component c). Specific examples of 2,2-dimethylol alkanoic acid include 2,2-dimethylol propionic acid (when R 6 is a methyl group) and 2,2-dimethylol butanoic acid (when R 6 is an ethyl group). Can be mentioned.
• either one of 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid may be used, or both may be used in combination.
• a polyol other than the raw material compound represented by the formula (2) or 2,2- Polyurethanes other than dimethylolalkanoic acid may be used.
• oligomer polyols and low molecular weight polyols can be used.
• the polyol of the oligomer include polyester polyols and polycarbonate diols other than the raw material compound represented by the formula (2).
• low molecular weight polyols include 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol.
• One of these polyols may be used alone, or two or more thereof may be used in combination.
• the method for synthesizing polyurethane which is an example of the polymer (component c), is not particularly limited, but is represented by the formula (2) in the presence or absence of a urethanization catalyst such as dibutyltin dilaurylate.
• a urethanization catalyst such as dibutyltin dilaurylate.
• a method of polymerizing a raw material compound, 2,2-dimethylol alkanoic acid, and a diisocyanate compound having two isocyanato groups in one molecule (for example, the diisocyanate compound has 6 to 14 carbon atoms) in a solvent can be mentioned. Be done.
• a polyol other than the raw material compound represented by the formula (2) a polyol other than 2,2-dimethylolalkanoic acid, a monohydroxy compound having one hydroxy group in one molecule, and one molecule.
• At least one of the monoisocyanate compounds having one isocyanato group may coexist in the compound to carry out the above polymerization reaction. Further, it is preferable to carry out the above polymerization reaction without a catalyst or in the presence of a small amount of catalyst because the long-term insulation reliability of the overcoat film described later is improved.
• raw materials such as monomers are charged into the reaction vessel when the polymerization reaction for synthesizing polyurethane is carried out, but for example, they may be charged in the following order. That is, after the raw material compound represented by the formula (2) and 2,2-dimethylol alkanoic acid are dissolved in a solvent in a reaction vessel, the temperature is 30 ° C. or higher and 140 ° C. or lower, preferably 60 ° C. or higher and 120 ° C. or lower. Then, the diisocyanate compound is added little by little to the reaction vessel, and each of the above monomers is reacted at 50 ° C. or higher and 160 ° C. or lower, preferably 60 ° C. or higher and 150 ° C. or lower to carry out polymerization.
• the molar ratio of the monomer charged is adjusted according to the molecular weight and acid value of the target polyurethane.
• a monohydroxy compound may be used as a raw material for polyurethane for adjusting the molecular weight of polyurethane. In that case, when the molecular weight of the polyurethane being polymerized reaches the target number average molecular weight (or approaches the target number average molecular weight) by the above method, the isocyanato group at the molecular end of the polyurethane being polymerized is sealed.
• a monohydroxy compound is added for the purpose of stopping and suppressing a further increase in the number average molecular weight.
• the total number of hydroxy groups obtained by subtracting the total number of hydroxy groups of the monohydroxy compound from the total number of hydroxy groups of all the raw materials of polyurethane that is, two in one molecule which is the raw material of polyurethane.
• the total number of isocyanato groups contained in all the raw materials of polyurethane may be smaller, the same, or larger than the total number of hydroxy groups contained in the above compounds having hydroxy groups.
• the excess monohydroxy compound may be used as it is as a part of the solvent. Alternatively, it may be removed by an operation such as distillation.
• the reason why the monohydroxy compound is used as a raw material for polyurethane is to suppress the increase in the molecular weight of polyurethane (that is, to stop the polymerization reaction), and the monohydroxy compound is contained in the reaction solution at 30 ° C. or higher and 150 ° C. or lower, preferably 70 ° C. or higher. Add in small portions at °C or more and 140 °C or less, and then hold at the above temperature to complete the reaction.
• the type of monohydroxy compound is not particularly limited, and examples thereof include n-butanol, isobutanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, amyl alcohol, hexyl alcohol, octyl alcohol, and methyl ethyl ketooxime. ..
• a monoisocyanate compound may be used as a raw material for polyurethane in order to adjust the molecular weight of polyurethane.
• the total number of isocyanato groups contained in all the raw materials of polyurethane is used rather than the total number of hydroxy groups contained in all raw materials of polyurethane so that the molecular terminal of the polyurethane at the time of adding the monoisocyanate compound becomes a hydroxy group.
• the temperature of the polyurethane solution during polyurethane production is set to 30 ° C. or higher and 150 ° C. or lower, preferably 70 ° C. or higher and 140 ° C. or lower, and then the monoisocyanate compound is added little by little to the polyurethane solution and then maintained at the above temperature. Complete the reaction.
• the type of the monoisocyanate compound is not particularly limited, and examples thereof include cyclohexyl isocyanate, octadecyl isocyanate, phenyl isocyanate, and toluyl isocyanate.
• the synthetic solvent used in producing this polyurethane can be used as it is as a part or all of the solvent (component b) which is one component of the curable composition described later. This is preferable in terms of process because the curable composition of the present embodiment can be easily produced.
• the curable composition of the present embodiment may contain at least one kind of fine particles (component d) selected from the group consisting of inorganic fine particles and organic fine particles.
• the inorganic fine particles include silica (SiO 2 ), alumina (Al 2 O 3 ), titanium (TIO 2 ), titanium oxide (Ta 2 O 5 ), zirconia (ZrO 2 ), and silicon nitride (Si 3 N 4 ).
• organic fine particles fine particles of a heat-resistant resin having an amide bond, an imide bond, an ester bond or an ether bond are preferable.
• these resins include polyimide resins or precursors thereof, polyamideimide resins or precursors thereof, or polyamide resins from the viewpoint of heat resistance and mechanical properties.
• silica fine particles are preferable, and the curable composition of the present embodiment preferably contains silica fine particles.
• the silica fine particles used in the curable composition of the present embodiment are in the form of powder, and may be silica fine particles having a coating on the surface or silica fine particles chemically surface-treated with an organic compound.
• the silica fine particles used in the curable composition of the present embodiment are not particularly limited as long as they are dispersed in the curable composition to form a paste, but for example, from Nippon Aerosil Co., Ltd.
• Examples include Aerosil (trade name) provided.
• Silica fine particles typified by Aerosil (trade name) are sometimes used to impart printability at the time of screen printing to a curable composition, and in that case, they are used for the purpose of imparting tincture. ..
• the mass average particle diameter of these inorganic fine particles and organic fine particles is preferably 0.01 ⁇ m or more and 10 ⁇ m or less, and more preferably 0.1 ⁇ m or more and 5 ⁇ m or less.
• the content of the fine particles (component d) in the curable composition of the present embodiment is based on the total amount of the epoxy compound (component a), the solvent (component b), the polymer (component c) and the fine particles (component d). , 0.1% by mass or more and 60% by mass or less, more preferably 0.5% by mass or more and 40% by mass or less, and further preferably 1% by mass or more and 20% by mass or less.
• the content of the fine particles (component d) in the curable composition of the present embodiment is within the above range, the viscosity of the curable composition is good for printing by the screen printing method, and The spread due to bleeding of the curable composition after screen printing is not so large. As a result, the phenomenon that the printed area of the curable composition actually printed is larger than the portion to which the curable composition is to be applied (that is, the shape of the printing plate) is less likely to occur, which is preferable.
• the content of the solvent (component b) in the curable composition of the present embodiment is determined by the curable composition of the present embodiment. That is, it is preferably 25% by mass or more and 75% by mass or less with respect to the total amount of the epoxy compound (component a), the solvent (component b), the polymer (component c) and the fine particles (component d). It is more preferably 30% by mass or more and 75% by mass or less, and further preferably 35% by mass or more and 70% by mass or less.
• the viscosity of the curable composition is in the screen printing method.
• the viscosity is good for printing, and the spread of the curable composition after screen printing due to bleeding is not so large.
• screen printing is performed. Printability (good plate release, etc.) is improved.
• the epoxy compound with respect to the total amount of the epoxy compound (component a) and the polymer (component c) in the curable composition of the present embodiment is preferably 1% by mass or more and 60% by mass or less, more preferably 2% by mass or more and 50% by mass or less, and 3% by mass or more and 40% by mass or less. Is even more preferable. That is, the ratio of the content of the polymer (component c) to the total amount of the epoxy compound (component a) and the polymer (component c) in the curable composition of the present embodiment is 40% by mass or more and 99% by mass or less. It is more preferable, it is more preferably 50% by mass or more and 98% by mass or less, and further preferably 60% by mass or more and 97% by mass or less.
• the ratio of the content of the epoxy compound (component a) to the total amount of the epoxy compound (component a) and the polymer (component c) is 1.
• it is mass% or more and 60% by mass or less, it is possible to balance the low warpage property of the flexible wiring board described later, which is coated with the overcoat film described later, and the disconnection suppressing property of the wiring.
• a curing accelerator (component e) may be added to the curable composition of the present embodiment.
• the type of the curing accelerator is not particularly limited as long as it is a compound that promotes the reaction between the functional group (for example, carboxy group) of the polymer (component c) and the epoxy group of the epoxy compound (component a).
• the functional group for example, carboxy group
• the following compounds may be mentioned.
• curing accelerators include melamine, acetoguanamine, benzoguanamine, 2,4-diamino-6-methacryloyloxyethyl-s-triazine, 2,4-methacryloyloxyethyl-s-triazine, and 2,4-diamino.
• examples thereof include triazine compounds such as -6-vinyl-s-triazine and 2,4-diamino-6-vinyl-s-triazine / isocyanuric acid adduct.
• curing accelerators examples include imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecyl imidazole, 2-heptadecyl imidazole, 1-benzyl-2-methyl.
• Imidazole 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-aminoethyl-2-ethyl-4-methylimidazole, 1-amino Ethyl-2-methylimidazole, 1- (cyanoethylaminoethyl) -2-methylimidazole, N- [2- (2-methyl-1-imidazolyl) ethyl] urea, 1-cyanoethyl-2-undecylimidazole, 1- Cyanoethyl-2-methylimidazolium trimerite, 1-cyanoethyl-2-phenylimidazolium trimerite, 1-cyanoethyl-2-ethyl-4-methylimidazolium trimerite, 1-cyanoethyl-2-undecylimidazole Rium trimerite, 2,4-dia
• examples of the curing accelerator include cycloamidine compounds such as diazabicycloalkene and salts thereof and derivatives thereof.
• examples of the diazabicycloalkene include 1,5-diazabicyclo (4.3.0) nonene-5 and 1,8-diazabicyclo (5.4.0) undecene-7.
• curing accelerators include triphenylphosphine, diphenyl (p-tryl) phosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) phosphine, tris (alkyl alkoxyphenyl) phosphine, tris (dialkylphenyl).
• Trisphine tris (trialkylphenyl) phosphine, tris (tetraalkylphenyl) phosphine, tris (dialkoxyphenyl) phosphine, tris (trialkoxyphenyl) phosphine, tris (tetraalkoxyphenyl) phosphine, trialkylphosphine, dialkylarylphosphine, Examples include organic phosphine compounds such as alkyldiarylphosphine.
• examples of the curing accelerator include amine compounds such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol, and dicyandiazide.
• amine compounds such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol, and dicyandiazide.
• One of these curing accelerators may be used alone, or two or more thereof may be used in combination.
• melamine imidazole compound, cycloamidine compound and its derivative, phosphine compound, and amine compound are considered in consideration of both the curing promoting action and the electrical insulation performance of the cured product of the present embodiment described later.
• melamine 1,5-diazabicyclo (4.3.0) nonen-5 and a salt thereof, 1,8-diazabicyclo (5.4.0) undecene-7 and a salt thereof are more preferable.
• the content of the curing accelerator (component e) in the curable composition of the present embodiment is not particularly limited as long as the curing promoting effect is exhibited, but the curability of the curable composition of the present embodiment is not particularly limited.
• the total amount of the epoxy compound (component a) and the polymer (component c) is 100 parts by mass, and the curing accelerator (component e) is used.
• the curable composition of the present embodiment can be cured in a short time, and the present invention described later.
• the cured product of the embodiment and the overcoat film have good electrical insulation characteristics and water resistance.
• the curable composition of the present embodiment is used, for example, for resist ink for insulating and protecting wiring. It can be used as a composition.
• the curable composition of the present embodiment is used as a composition for resist ink for insulating and protecting wiring (that is, a composition for forming an overcoat film of a flexible wiring board), bubbles are generated during printing.
• An antifoaming agent (component f) may be added for the purpose of preventing or suppressing.
• the type of defoaming agent is such that the generation of bubbles can be prevented or suppressed when the curable composition of the present embodiment is printed and applied on the surface of the flexible substrate at the time of manufacturing the flexible wiring board.
• the following antifoaming agents can be mentioned as examples. That is, examples of defoamers include BYK-077 (manufactured by Big Chemie Japan Co., Ltd.), SN Deformer 470 (manufactured by Sannopco Co., Ltd.), TSA750S (manufactured by Momentive Performance Materials Co., Ltd.), and silicone oil SH-203 (manufactured by Momentive Performance Materials).
• Silicone defoamers such as Toray Dow Corning Co., Ltd., Dappo SN-348 (San Nopco Co., Ltd.), Dappo SN-354 (San Nopco Co., Ltd.), Dappo SN-368 (San Nopco Co., Ltd.), Acrylic polymerization system defoamers such as Disparon 230HF (manufactured by Kusumoto Kasei Co., Ltd.), Surfinol DF-110D (manufactured by Nisshin Chemical Industry Co., Ltd.), Surfinol DF-37 (manufactured by Nisshin Chemical Industry Co., Ltd.), etc. Examples thereof include an acetylene diol-based defoaming agent and a fluorine-containing silicone-based defoaming agent such as FA-630.
• the content of the defoaming agent (component f) in the curable composition of the present embodiment is not particularly limited, but the epoxy compound (component a), the solvent (component b), the polymer (component c), and the like.
• the total amount of the fine particles (component d) is 100 parts by mass, and the defoamer (component f) is preferably blended in the range of 0.01 part by mass or more and 5 parts by mass or less, and 0.05 parts by mass or more and 4 parts by mass. It is more preferable to blend in the range of 0.1 parts by mass or less, and further preferably in the range of 0.1 parts by mass or more and 3 parts by mass or less.
• the curable composition of the present embodiment may contain a surfactant such as a leveling agent, phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, carbon black, naphthalene black, if necessary. And other colorants can be added.
• a surfactant such as a leveling agent, phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, carbon black, naphthalene black, if necessary.
• a surfactant such as a leveling agent, phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, carbon black, naphthalene black, if necessary.
• other colorants can be added.
• an antioxidant such as a phenol-based antioxidant, a phosphite-based antioxidant, or a thioether-based antioxidant. It is preferably added to the curable composition of the present embodiment. Further, a flame retardant or a lubricant can be added to the curable composition of the present embodiment, if necessary.
• the curable composition of the present embodiment contains a part or all of the components to be blended (that is, the epoxy compound (component a), the solvent (component b), the polymer (component c), the fine particles (component d), etc.). It can be obtained by uniformly kneading and mixing with a roll mill, a bead mill or the like. When a part of the components to be blended is mixed, the remaining components can be mixed when the curable composition of the present embodiment is actually used.
• the viscosity of the curable composition of the present embodiment at 25 ° C. is preferably 10,000 mPa ⁇ s or more and 100,000 mPa ⁇ s or less, and more preferably 20,000 mPa ⁇ s or more and 60,000 mPa ⁇ s or less.
• the viscosity of the curable composition of the present embodiment at 25 ° C. is a cone / plate type viscometer (manufactured by Brookfield, model DV-II + Pro, model number CPE- of spindle) unless otherwise specified. It is the viscosity measured 7 minutes after the start of rotation under the condition of a rotation speed of 10 rpm using 52). In measuring the viscosity of this curable composition, about 0.8 g of the curable composition is used.
• the curable composition of the present embodiment is used as a composition for resist ink for insulating and protecting wiring (that is, a composition for forming an overcoat film of a flexible wiring board), the curable composition of the present embodiment
• the thixotropy index at 25 ° C. is preferably 1.1 or more, more preferably 1.1 or more and 3.0 or less, and 1.1 or more and 2.5 or less. Is even more preferable.
• the curable composition of the present embodiment When the curable composition of the present embodiment is used as an overcoat film-forming composition for a flexible wiring board, if the curable composition of the present embodiment has a thixotropy index of 1.1 or more at 25 ° C.
• the curable composition of the embodiment has good printability (for example, printability in screen printing), and the printed curable composition of the present embodiment does not easily flow and is maintained in a film shape having a constant thickness. It is easy to maintain the print pattern.
• the thixotropy index is adjusted by using the above-mentioned inorganic fine particles or organic fine particles, or the thixotropy index is adjusted by using a polymer additive.
• the method of adjusting the thixotropy index using inorganic fine particles or organic fine particles is preferable.
• the thixotropy index of the curable composition of the present embodiment at 25 ° C. is the ratio of the viscosity measured at a rotation speed of 1 rpm at 25 ° C. to the viscosity measured at a rotation speed of 10 rpm at 25 ° C. [Viscosity when the rotation speed is 1 rpm] / [Viscosity when the rotation speed is 10 rpm]). These viscosities can be measured using a cone / plate viscometer (Brookfield, model DV-II + Pro, spindle model number CPE-52). These viscosity measurements are those measured 7 minutes after the start of spindle rotation. Further, in measuring the viscosity of this curable composition, about 0.8 g of the curable composition is used.
• the cured product of the present embodiment is a cured product obtained by curing the curable composition of the present embodiment, has good low warpage and flexibility, and has excellent long-term insulation reliability. ..
• the method for curing the curable composition of the present embodiment is not particularly limited, and the curable composition can be cured by heat or active energy rays (for example, ultraviolet rays, electron beams, X-rays). Therefore, a polymerization initiator such as a thermal radical generator or a photoradical generator may be added to the curable composition of the present embodiment.
• the cured product of this embodiment can be used as an insulating protective film (overcoat film).
• the cured product of this embodiment can be used as an insulating protective film for wiring by covering all or part of the wiring of a flexible wiring board such as a chip-on film (COF).
• COF chip-on film
• Overcoat film and flexible wiring board and method for manufacturing the overcoat film of the present embodiment is a film containing a cured product of the present embodiment, and can be produced by curing the curable composition of the present embodiment. it can. More specifically, the overcoat film of the present embodiment is formed by forming the curable composition of the present embodiment into a film on all or a part of the surface of the flexible substrate on which the wiring is formed. After the arrangement, it can be produced by curing the film-like curable composition by heating or the like to obtain a film-like cured product.
• the overcoat film of this embodiment is suitable as an overcoat film for a flexible wiring board.
• the flexible wiring board of the present embodiment all or a part of the surface of the flexible substrate on which the wiring is formed is covered with an overcoat film.
• the flexible wiring board of the present embodiment can be manufactured from the curable composition of the present embodiment and a flexible substrate. More specifically, in the flexible wiring board of the present embodiment, the curable composition of the present embodiment is formed into a film on all or a part of the surface of the flexible substrate on which the wiring is formed. After the arrangement, it can be produced by curing the film-like curable composition to form an overcoat film.
• the wiring covered with the overcoat film is preferably tin-plated copper wiring in consideration of antioxidant and economical aspects of the wiring.
• the overcoat film and the flexible wiring board of the present embodiment can be formed, for example, through the following steps 1, 2, and 3.
• Step 1 A printing step of forming a printing film on at least a part of a wiring pattern portion of a flexible substrate by printing the curable composition of the present embodiment on the wiring pattern portion.
• Step 2 A solvent removing step of evaporating part or all of the solvent in the printing film by placing the printing film obtained in step 1 in an atmosphere of 40 ° C. or higher and 100 ° C. or lower.
• Step 3) A curing step of forming an overcoat film by curing the printing film obtained in step 1 or the printing film obtained in step 2 by heating at 80 ° C. or higher and 160 ° C. or lower.
• the method for printing the curable composition in step 1 is not particularly limited.
• the curable composition of the present embodiment is coated on a flexible substrate by a screen printing method, a roll coater method, a spray method, a curtain coater method, or the like.
• the printing film can be obtained.
• Step 2 is an operation performed as needed, and step 3 may be performed immediately after step 1, and the curing reaction and solvent removal may be performed simultaneously in step 3.
• the temperature is preferably 40 ° C. or higher and 100 ° C. or lower, and 60 ° C. or higher and 90 ° C. or lower, in consideration of the evaporation rate of the solvent and the rapid transition to the thermosetting operation.
• the temperature is 70 ° C. or higher and 80 ° C. or lower.
• the time for evaporating the solvent in step 3 and step 2 is not particularly limited, but is preferably 10 minutes or more and 120 minutes or less, and more preferably 20 minutes or more and 100 minutes or less.
• the thermosetting temperature in step 3 is more preferably 105 ° C. or higher and 160 ° C. or lower from the viewpoint of preventing diffusion of the plating layer and imparting low warpage and flexibility suitable as a protective film to the overcoat film. It is preferable that the temperature is 110 ° C. or higher and 160 ° C. or lower.
• the thermosetting time performed in the step 3 is not particularly limited, but is preferably 10 minutes or more and 150 minutes or less, and more preferably 15 minutes or more and 120 minutes or less.
• the flexible wiring board of the present embodiment is also excellent in flexibility and flexibility, and the flexible wiring board is shaken. Even so, it is difficult for wiring to break (excellent in suppressing wiring breaks). Therefore, the flexible wiring board of the present embodiment is less likely to cause cracks, and is suitable for a flexible printed wiring board used in a technique such as chip-on-film (COF).
• COF chip-on-film
• the flexible wiring board of the present embodiment since the curable composition of the present embodiment is less likely to shrink during curing, the flexible wiring board of the present embodiment has a small warp. Therefore, in the process of mounting the IC chip on the flexible wiring board of the present embodiment, it is easy to align the mounting position of the IC chip. Further, since the overcoat film has excellent long-term insulation reliability, the flexible wiring board of the present embodiment also has excellent long-term insulation reliability.
• polyester diol> (Reference synthesis example 1) 983.5 g (6.74 mol) of phthalic anhydride and 879.2 g (7.44 mol) of 1,6-hexanediol were put into a reaction vessel equipped with a stirrer, a thermometer and a condenser with a distillation device, and an oil bath was added. The internal temperature of the reaction vessel was raised to 140 ° C. and stirring was continued for 4 hours. Then, while continuing stirring, 1.74 g of mono-n-butyltin oxide was added.
• polyurethane solution A1 a solution containing polyurethane having a carboxy group, an aromatic ring concentration of 3.1 mmol / g, and a carbamate group concentration of 2.02 mmol / g
• the viscosity of the obtained polyurethane solution A1 was 120,000 mPa ⁇ s.
• the number average molecular weight (Mn) of polyurethane contained in the polyurethane solution A1 was 15,000, and the acid value was 25.0 mgKOH / g.
• the solid content concentration in the polyurethane solution A1 was 40.0% by mass.
• the viscosity of the obtained polyurethane solution A2 was 120,000 mPa ⁇ s.
• the number average molecular weight (Mn) of polyurethane contained in the polyurethane solution A2 was 15,000, and the acid value was 24.8 mgKOH / g.
• the solid content concentration in the polyurethane solution A2 was 40.0% by mass.
• the viscosity of the obtained polyurethane solution A3 was 120,000 mPa ⁇ s.
• the number average molecular weight (Mn) of polyurethane contained in the polyurethane solution A3 was 15,000, and the acid value was 24.9 mgKOH / g.
• the solid content concentration in the polyurethane solution A3 was 40.0% by mass.
• the viscosity of the obtained polyurethane solution A4 was 70,000 mPa ⁇ s.
• the number average molecular weight (Mn) of polyurethane contained in the polyurethane solution A4 was 6200, and the acid value was 40.0 mgKOH / g.
• the solid content concentration in the polyurethane solution A4 was 45.0% by mass.
• the viscosity of the obtained polyurethane solution A5 was 280000 mPa ⁇ s.
• the number average molecular weight (Mn) of polyurethane contained in the polyurethane solution A5 was 14,000, and the acid value was 40.0 mgKOH / g.
• the solid content concentration in the polyurethane solution A5 was 45.0% by mass.
• the viscosity of the obtained polyurethane solution A6 was 100,000 mPa ⁇ s.
• the number average molecular weight (Mn) of polyurethane contained in the polyurethane solution A6 was 14,000, and the acid value was 20.0 mgKOH / g.
• the solid content concentration in the polyurethane solution A6 was 40.0% by mass.
• the viscosity of the obtained polyurethane solution A7 was 128,000 mPa ⁇ s.
• the number average molecular weight (Mn) of polyurethane contained in the polyurethane solution A7 was 13000, and the acid value was 20.0 mgKOH / g.
• the solid content concentration in the polyurethane solution A7 was 40.0% by mass.
• the number average molecular weight of polyurethane is a polystyrene-equivalent number average molecular weight measured by GPC.
• the measurement conditions of GPC are as described above.
• the viscosity of polyurethane solution The viscosity of the polyurethane solution was measured using a cone / plate viscometer (manufactured by Brookfield, model DV-II + Pro, spindle model number CPE-52) at a temperature of 25.0 ° C. and a rotation speed of 5 rpm. The measured value is the viscosity measured 7 minutes after the start of rotation of the spindle. Moreover, in the measurement of the viscosity, about 0.8 g of the polyurethane solution was used.
• the aromatic ring concentration means the number (number of moles) of aromatic rings contained in 1 g of the compound. For example, if a polyurethane having a molecular weight of 438.5 as a repeating unit (structural unit) has four aromatic rings (for example, phenyl groups) per repeating unit, the number of repeating units in 1 g of this polyurethane is 2. Since it is .28 mmol, the aromatic ring concentration is 9.12 mmol / g (4 ⁇ 2.28 mmol / 1 g).
• the type of aromatic ring is not particularly limited as long as it is a cyclic functional group having aromaticity with 3 or more ring members, and for example, a monocyclic aromatic hydrocarbon group such as a phenyl group, a biphenyl group, or a fluorene group.
• a monocyclic aromatic hydrocarbon group such as a phenyl group, a biphenyl group, or a fluorene group.
• examples thereof include a polycyclic aromatic hydrocarbon group such as, a condensed ring aromatic hydrocarbon group such as a naphthalene group and an indenyl group, and a heteroaromatic hydrocarbon group such as a pyridyl group.
• the number of aromatic rings is not one but the number of cyclic structural parts.
• a fluorene group has two benzene rings which are cyclic structure sites
• the number of aromatic rings possessed by the polyurethane is 1 repeating unit. Two per piece.
• the number of aromatic rings is 2, in the case of an anthracene group or phenanthrene group, the number of aromatic rings is 3, and in the case of a triphenylene group or binaphthyl group, the number of aromatic rings is 4.
• the aromatic ring concentration can be calculated from the charging ratio of the monomers, but can be obtained by 1 H-NMR analysis after determining the structure of the polyurethane by spectroscopic methods such as 1 H-NMR, 13 C-NMR, and IR. It can also be calculated by comparing the number of protons derived from the aromatic ring with the number of protons derived from one repeating unit using the integration curve.
• ⁇ Manufacturing of curable composition > 88.71 parts by mass of the main agent formulation C1 and 4.21 parts by mass of the curing agent solution E2 were placed in a plastic container, and 3.5 parts by mass of diethylene glycol diethyl ether and 1.5 parts by mass of diethylene glycol ethyl ether acetate were added as solvents. Added. The mixture was stirred at room temperature for 5 minutes using a spatula to obtain a curable composition F1.
• the curable composition F1 had a viscosity of 32000 mPa ⁇ s at 25 ° C. and a thixotropy index of 1.15.
• the main agent formulations C1 to C7, the curing agent solutions E1 to E4, and the solvent are mixed according to the formulation composition shown in Table 2.
• curable compositions F2 to F9 were obtained, respectively (see Table 2).
• the viscosities and thixotropy indexes of the curable compositions F2 to F9 at 25 ° C. are as shown in Table 2.
• Table 2 shows the amounts (unit: parts by mass) of the epoxy compounds (component a), solvent (component b), polymer (component c), and fine particles (component d) contained in the curable compositions F1 to F9. Shown.
• a test piece composed of a cured product of the curable compositions F1 to F9 was prepared, and its tensile elastic modulus and tensile yield strength were measured.
• the curable composition was applied onto a base material such as a glass plate so that the film thickness after curing was 50 ⁇ m.
• the substrate coated with the curable composition was held at room temperature for 10 minutes and then placed in a hot air circulation dryer at a temperature of 120 ° C. for 120 minutes to cure the curable composition to obtain a cured product. After peeling the film-like cured product from the substrate, it was cut out to prepare a strip-shaped test piece having a width of 1 cm and a length of 5 cm. Then, the tensile elastic modulus and the tensile yield strength of the test piece were measured under the conditions as described above in the section of Tensile Test Conditions. The results are shown in Table 2.
• the curable composition was applied onto the flexible wiring board by a screen printing method.
• the thickness of the film of the printed curable composition was set so that the thickness of the film of the curable composition on the polyimide surface after drying was 10 ⁇ m.
• the flexible wiring board thus obtained was placed in a hot air circulation dryer having a temperature of 80 ° C. for 30 minutes, and then placed in a hot air circulation dryer having a temperature of 120 ° C. for 120 minutes to cure the flexible wiring board formed on the flexible wiring board.
• the film of the sex composition was cured.
• a MIT test was performed by the method described in JIS C5016 to evaluate the disconnection inhibitory property of the wiring of the flexible wiring board.
• the test conditions for the MIT test are as follows.
• the substrate coated with the curable composition thus obtained is placed in a hot air circulation dryer at a temperature of 80 ° C. for 30 minutes, and then placed in a hot air circulation dryer at a temperature of 120 ° C. for 60 minutes.
• the film of the curable composition formed on the substrate was cured.
• the base material having the cured product film was cut with a circle cutter to obtain a circular base material having a cured product film and having a diameter of 50 mm (hereinafter referred to as “substrate”).
• substrate exhibits a deformation in which the vicinity of the center warps in a convex or concave shape.
• the substrate After leaving the substrate at 23 ° C. for 1 hour, the substrate is placed on a flat plate in a downwardly convex state. That is, the convex portion near the center of the warped substrate is placed on the flat plate with the convex portion facing downward so that the convex portion of the warped substrate is in contact with the horizontal plane of the flat plate. Then, the distance of the portion of the peripheral edge of the warped substrate farthest from the horizontal plane of the flat plate and the distance of the closest portion were measured, the average value was obtained, and the warpage property was evaluated by this average value.
• Table 3 The numerical values shown in Table 3 indicate the direction of warpage.
• the curable composition was applied onto the flexible wiring board by a screen printing method.
• the thickness of the film of the printed curable composition was set so that the thickness of the film of the curable composition on the polyimide surface after drying was 15 ⁇ m.
• the flexible wiring board thus obtained was placed in a hot air circulation dryer having a temperature of 80 ° C. for 30 minutes, and then placed in a hot air circulation dryer having a temperature of 120 ° C. for 120 minutes to cure the flexible wiring board formed on the flexible wiring board.
• the film of the sex composition was cured.
• the cured products of the curable compositions F1 to F6 satisfy the requirements of the present invention in terms of tensile elastic modulus and tensile yield strength, whereas the curable compositions F7 to F7 to The cured product of F9 does not meet the requirements of the present invention in terms of tensile elastic modulus and tensile yield strength. Therefore, the flexible wiring boards of Examples 1 to 6 having an overcoat film made of a cured product of the curable compositions F1 to F6 have an overcoat film made of a cured product of the curable compositions F7 and F8. Compared to the flexible wiring boards of No.
• the film made of the cured product of the curable compositions F1 to F6 is useful as an insulating protective film for a flexible wiring board.

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• 2020
  • 2020-05-29 JP JP2021530524A patent/JP7521814B2/ja active Active
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