Classifications

• • 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
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/38—Layered products comprising a layer 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
  • C08G59/20—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 epoxy compounds used
  • C08G59/22—Di-epoxy compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J163/00—Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J171/00—Adhesives based on polyethers obtained by reactions forming an ether link in the main chain; Adhesives based on derivatives of such polymers
  • C09J171/08—Polyethers derived from hydroxy compounds or from their metallic derivatives
  • C09J171/10—Polyethers derived from hydroxy compounds or from their metallic derivatives from phenols
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J5/00—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers

Definitions

• the present invention relates to a curable resin composition, a cured product, and a dismantlable adhesive material comprising the cured product.
• the cured products obtained from epoxy resins have excellent heat resistance, mechanical strength, electrical properties, and adhesive properties, making them indispensable materials in a variety of fields, including electrical and electronics, paints, and adhesives.
• thermosetting resins such as epoxy resins
• cured products made from thermosetting resins have low long-term reliability.
• a cured epoxy resin deteriorates due to oxidation, cracks may occur.
• thermosetting resins such as epoxy resins
• the hardened product obtained by hardening thermosetting resins cannot be dissolved in solvents (is insoluble) and does not dissolve even at high temperatures (is infusible). For this reason, they are poorly recyclable and reusable, and the hardened products become waste after use, making it an issue to reduce waste and the burden on the environment.
• thermosetting resins are mixed with thermally expandable materials or thermally decomposable compounds in advance, and after use, mainly thermal energy is applied to reduce the adhesive strength and allow peeling (see, for example, Patent Documents 1 and 2).
• Patent Document 1 basically uses a conventional curable resin composition as an adhesive. Therefore, it is difficult to fully develop foaming due to the thermal expansion material in the cured product (adhesive layer). As a result, the peelability may be insufficient, or the adhesive layer may be too brittle to be removed cleanly.
• a thermally decomposable compound is already contained. This requires a high degree of control over the heating temperature during the curing reaction. This makes the use complicated. In particular, when using a metal substrate with high thermal conductivity, it cannot be denied that the adhesive may be exposed to too much heat in an unexpected location, causing problems.
• an object of the present invention is to provide a curable resin composition which, although being a curable resin, has excellent adhesion, flexibility and dismantlability in the cured product, a cured product thereof, and a dismantlable adhesive material comprising the cured product.
• R 11 and R 12 each independently represent a glycidyl ether group or a 2-methylglycidyl ether group
• R 13 and R 14 each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group
• R 15 and R 16 each represent a hydrogen atom or a methyl group
• m1, m2, p1, p2, and q are the average values of the repetitions, m1 and m2 each independently represent 0 to 25, and m1+m2 ⁇ 1; p1 and p2 each independently represent 0 to 5; and q is 0.5 to 5.
• the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
• the furan-derived structures in formulae (4-1) and (4-2) may have a halogen atom, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amide group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group as a substituent.
• n a and n b are the average number of repetitions and each is independently 0 to 10.
• m is an integer from 1 to 4.
• Z 1 is any of the structures represented by formula (5) below
• Z 2 is any of the structures represented by formulae (6A) and (6B) below
• Z 3 is any of the structures represented by formulae (7-1) to (7-3) below, and each of the multiple structures present in one molecule may be the same or different.
• the aromatic ring in formula (5) may be substituted or unsubstituted, * represents a bonding point, Fg is a curable functional group, and -Fg on the naphthalene ring in the formula indicates that it may be bonded to any position.
• each Ar independently represents a structure having an unsubstituted or substituted aromatic ring
• R 1 and R 2 each independently represent a hydrogen atom, a methyl group, or an ethyl group
• R is a hydrogen atom or a methyl group
• R' is
• the structural unit X represented by the formula (6-1) and the structural unit Y represented by the formula (6-2) may be bonded randomly or in blocks, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
• n3 and n5 are average numbers of repeating units, each of which is 0.5 to 10
• n4 is an integer of 1 to 16
• each R′′ is independently a hydrogen atom, a methyl group, or an ethyl group.
• thermoly expandable particles (D) are at least one selected from the group consisting of thermally expandable microcapsules and expandable graphite.
• proportion of the thermally expandable particles (D) used is in the range of 3 to 40 parts by mass per 100 parts by mass of the total of the epoxy resin (A) and the epoxy resin (B).
• a heat-resistant member comprising the cured product according to [8].
• a dismantling method using the dismantlable adhesive material according to [11] A bonding step of attaching the dismantlable adhesive material to a surface of an adherend and bonding the material to the adherend; and a curing step of curing the dismantlable adhesive material to obtain a cured product.
• the dismantling method according to [12] further comprising, after the heat treatment step and before the dismantling step, a cooling step of cooling the heat-treated hardened product to room temperature.
• the present invention provides a curable resin composition that has excellent adhesiveness, flexibility, and dismantling properties after curing.
• the curable resin composition as one embodiment (present embodiment) of the present invention is a curable resin composition comprising: an epoxy resin (A) represented by the above general formula (1) and having an epoxy equivalent of 500 to 10,000 g/eq; an epoxy resin (B) represented by the above general formula (1) and having an epoxy equivalent of 100 to 300 g/eq; a curable functional group-containing compound (C) represented by any one of the above general formulas (4-1) and (4-2); and thermally expandable particles (D).
• the curable functional group-containing compound (C) is preferably a hydroxyl group-containing compound or an amine group-containing compound.
• the curable resin composition of this embodiment may contain other epoxy resins other than the epoxy resin (A), the epoxy resin (B), and the curable functional group-containing compound (C) according to this embodiment, as necessary.
• the curable resin composition of this embodiment may contain, as necessary, a curing agent for epoxy resins that does not belong to the curable functional group-containing compound (C), a curing accelerator, other thermosetting resins or thermoplastic resins, a non-halogen flame retardant, a filler that does not belong to the thermally expandable particles (D) according to this embodiment, or a dispersion medium.
• the epoxy resin (A) contained in the curable resin composition of the present embodiment is an epoxy resin represented by the following general formula (1) and having an epoxy equivalent of 500 to 10,000 g/eq.
• each Ar is independently a structure having an unsubstituted or substituted aromatic ring
• X is a structural unit represented by the following general formula (2)
• Y is a structural unit represented by the following general formula (3):
• R 1 and R 2 each independently represent a hydrogen atom, a methyl group, or an ethyl group
• R' is a divalent hydrocarbon group having 2 to 12 carbon atoms
• R 3 , R 4 , R 7 and R 8 each independently represent a hydroxyl group, a glycidyl ether group or a 2-methylglycidyl ether group
• R 5 , R 6 , R 9 , and R 10 each independently represent a hydrogen atom or a methyl group
• n is an epoxy resin represented by the following general formula (1) and having an epoxy equivalent of 500 to 10,000
• R 11 and R 12 each independently represent a glycidyl ether group or a 2-methylglycidyl ether group
• R 13 and R 14 each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group
• R 15 and R 16 each represent a hydrogen atom or a methyl group
• m1, m2, p1, p2, and q are the average values of the repetitions, m1 and m2 each independently represent 0 to 25, and m1+m2 ⁇ 1
• p1 and p2 each independently represent 0 to 5; and q is 0.5 to 5.
• the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
• the above structure contains the structural unit X represented by general formula (2) and/or the structural unit Y represented by general formula (3), and the presence of the alkylene chain or polyether chain in each structural unit makes it possible to impart high flexibility to the cured product.
• the flexibility provided by the alkylene chain makes it possible to follow the thermal expansion of the substrate when used as an adhesive, and the polyether chain has the effect of lowering the viscosity of the epoxy resin (A) itself, which contributes to improving the coatability and processability of the curable resin composition.
• the structural units X and Y may each be present alone, or both structural units X and Y may be present in one molecule.
• X and Y may be bonded in a block bond or a random bond, and the total number of structural units X and Y contained in one molecule is m1 and m2, respectively.
• Ar in the general formula (1) representing the epoxy resin (A), Ar in the general formula (2) representing the structural unit X, and Ar in the general formula (3) representing the structural unit Y all have a structure having an aromatic ring that is unsubstituted or substituted.
• the aromatic ring is not particularly limited, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and a fluorene ring.
• Ar has any of the structures represented by the following structural formula (ar).
• aromatic ring in formula (ar) may be substituted or unsubstituted, and * represents a point of attachment.
• Ar can have structures represented by the following formulas:
• the aromatic ring of Ar may be substituted or unsubstituted.
• the substituent is preferably an alkyl group, a halogen atom, a glycidyl ether group, a 2-methylglycidyl ether group, or the like. It is preferably unsubstituted, or an alkyl group, a glycidyl ether group, or a 2-methylglycidyl ether group. It is preferable that there are two or less substituents per aromatic ring, more preferably one or less, and particularly preferably unsubstituted.
• R is a hydrogen atom or a methyl group.
• the repeating unit n1 is an integer from 4 to 16.
• n1 is 4 or more, the adhesive strength is improved and the deformation mode of the cured product is elastic deformation. Furthermore, when n1 is 16 or less, the decrease in crosslink density can be suppressed. It is preferably 4 to 15, and more preferably 6 to 12.
• R 1 and R 2 each independently represent a hydrogen atom, a methyl group, or an ethyl group
• R 3 and R 4 each independently represent a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group
• R 5 and R 6 each independently represent a hydrogen atom or a methyl group.
• R 3 and R 4 are preferably hydroxyl groups, and R 5 and R 6 are preferably hydrogen atoms.
• n2 is the average value of the repeating units and is 2 to 30. This range is preferred in terms of achieving a good balance between the viscosity of the epoxy resin (A) and the crosslink density of the resulting cured product. It is preferably 2 to 25, and more preferably 4 to 20.
• R' is a divalent hydrocarbon group having 2 to 12 carbon atoms. Within this range, the adhesive strength is improved and the deformation mode of the cured product is elastic. Preferably, R' is a divalent hydrocarbon group having 2 to 6 carbon atoms.
• the divalent hydrocarbon group is not particularly limited, and examples thereof include linear or branched alkylene groups, alkenylene groups, alkynylene groups, cycloalkylene groups, arylene groups, and aralkylene groups (divalent groups having an alkylene group and an arylene group).
• alkylene groups include methylene, ethylene, propylene, butylene, pentylene, hexylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene groups.
• alkenylene groups include vinylene, 1-methylvinylene, propenylene, butenylene, and pentenylene groups.
• alkynylene groups include ethynylene, propynylene, butynylene, pentynylene, and hexynylene groups.
• cycloalkylene groups include cyclopropylene, cyclobutylene, cyclopentylene, and cyclohexylene groups.
• arylene groups include phenylene, tolylene, xylylene, and naphthylene groups.
• ethylene groups, propylene groups, and tetramethylene groups are preferred from the viewpoint of the balance between the ease of raw material availability, the viscosity of the resulting epoxy resin (A), and the flexibility of the cured product.
• R 7 and R 8 are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R 9 and R 10 are each independently a hydrogen atom or a methyl group.
• R 7 and R 8 are preferably a hydroxyl group, and R 9 and R 10 are preferably a hydrogen atom.
• the epoxy resin (A) used in this embodiment is represented by the general formula (1).
• m1 and m2 are the average values of the repeating structural units X and Y, respectively, each independently ranging from 0 to 25, and m1+m2 ⁇ 1.
• R 11 and R 12 in the general formula (1) are each independently a glycidyl ether group or a 2-methylglycidyl ether group
• R 13 and R 14 are each independently a hydroxyl group, a glycidyl ether group or a 2-methylglycidyl ether group
• R 15 and R 16 are a hydrogen atom or a methyl group
• p1, p2 and q are average values of repetition
• p1 and p2 are each independently 0 to 5
• q is 0.5 to 5.
• R 11 and R 12 are a glycidyl ether group
• R 13 and R 14 are preferably a hydroxyl group
• R 15 and R 16 are preferably a hydrogen atom.
• p1 and p2 are 0 to 2
• q is preferably 0.5 to 2.
• the epoxy equivalent of the epoxy resin (A) used in this embodiment is 500 to 10,000 g/eq. This range ensures an excellent balance between flexibility and crosslink density of the resulting cured product. From the standpoint of ease of handling and a better balance between flexibility and crosslink density, a range of 600 to 8,000 g/eq is preferred, and a range of 800 to 5000 g/eq is even more preferred.
• examples of resins having both the structural unit X and the structural unit Y in one molecule include resins having the following structural formula:
• epoxy resins (A) examples of epoxy resins having the structural unit X include resins represented by the following structural formula:
• G is a glycidyl group
• n1 is an integer from 4 to 16
• m1, p1, p2 and q are the average values of the repeats
• m1 is 0.5 to 25
• p1 and p2 are each independently 0 to 5
• q is 0.5 to 5.
• each repeat unit present in the repeat unit may be the same or different.
• epoxy resins (A) examples of epoxy resins having the structural unit Y include resins represented by the following structural formula:
• G is a glycidyl group
• R' is a divalent hydrocarbon group having 2 to 12 carbon atoms
• n2 is the average value of the repeating units and is 2 to 30, m2, p1, p2, and q are the average values of the repeating units
• m2 is 0.5 to 25
• p1 and p2 are each independently 0 to 5
• q is 0.5 to 5.
• each repeating unit present in the repeating unit may be the same or different.
• the method for producing the epoxy resin (A) according to the present embodiment is not particularly limited, but for example, a method in which a diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain is reacted with an aromatic hydroxy compound (a2) in a molar ratio (a1)/(a2) in the range of 1/1.01 to 1/5.0 to obtain a hydroxy compound (corresponding to a precursor or intermediate of the epoxy resin (A)), and then the hydroxy compound is reacted with epihalohydrin (a3) is preferred from the viewpoints of easy availability of raw materials and ease of reaction.
• the product obtained by the reaction of the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain with an aromatic hydroxy compound (a2) to obtain a hydroxy compound may contain unreacted aromatic hydroxy compound (a2), but in the synthesis of the epoxy resin (A) used in this embodiment, the product may be directly subjected to the reaction with epihalohydrin (a3) in the next step, or the unreacted aromatic hydroxy compound (a2) may be removed.
• the abundance ratio of the unreacted aromatic hydroxy compound (a2) in the hydroxy compound to be subjected to the next step is preferably in the range of 0.1 to 30% by mass.
• the method for removing the unreacted aromatic hydroxy compound (a2) is not particularly limited, and can be carried out according to various methods. For example, column chromatography separation method utilizing the difference in polarity, distillation fractional distillation utilizing the difference in boiling point, alkaline aqueous extraction method utilizing the difference in solubility in alkaline water, etc. can be mentioned.
• alkaline aqueous extraction method is preferable in terms of efficiency, etc., since it does not involve thermal deterioration, and at this time, as the organic solvent used to dissolve the target substance, it is possible to use an organic solvent that is not miscible with water, such as toluene or methyl isobutyl ketone. In addition, it is particularly preferable to use methyl isobutyl ketone from the viewpoint of solubility with the target substance.
• the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain is not particularly limited.
• examples of diglycidyl ethers having an alkylene chain include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1,11-undecanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, 1,13-tridecanediol diglycidyl ether, 1,14-tetradecanediol diglycidyl ether, 1,15-pentadecanediol diglycidyl ether, 1,16-hexadecanediol diglycidyl ether, 2-methyl-1,11-undecanediol diglycidyl ether, 3-methyl-1
• Examples of diglycidyl ethers having a polyether chain include polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, polypentamethylene glycol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, and polyheptamethylene glycol diglycidyl ether. These may contain organic chlorine impurities generated during the glycidyl etherification of hydroxy compounds, and may contain organic chlorine such as 1-chloromethyl-2-glycidyl ether (chloromethyl form) represented by the following structure. These diglycidyl ethers may be used alone or in combination of two or more types.
• 1,4-butanediol diglycidyl ether 1,6-hexanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polytetramethylene glycol diglycidyl ether, as they provide an excellent balance between flexibility and heat resistance in the resulting cured product.
• the aromatic hydroxy compound (a2) is not particularly limited, and examples thereof include dihydroxybenzenes such as hydroquinone, resorcin, and catechol; trihydroxybenzenes such as pyrogallol, 1,2,4-trihydroxybenzene, and 1,3,5-trihydroxybenzene; triphenylmethane-type phenols such as 4,4',4"-trihydroxytriphenylmethane; dihydroxynaphthalenes such as 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene; and dihydroxynaphthalenes subjected to a coupling reaction.
• dihydroxybenzenes such as hydroquinone, resorcin, and catechol
• trihydroxybenzenes such as pyrogallol, 1,2,4-
• tetrafunctional phenols such as 1,1'-methylenebis-(2,7-naphthalenediol), 1,1'-binaphthalene-2,2',7,7'-tetraol, and 1,1'-oxybis-(2,7-naphthalenediol); bisphenols such as bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)-1-phenylethane and bis(4-hydroxyphenyl)sulfone; 2,2'-biphenol, 4,4'-biphenol, and (1,1'-biphenyl)-3,4-diphenyl ether; biphenols such as 3,3'-dimethyl-(1,1'-biphenyl)-4,4'-diol, 3-
• alicyclic structure-containing phenols and the Xylok-type phenolic resins may contain not only bifunctional components but also trifunctional or higher functional components at the same time. In the present invention, these may be used as they are, or only the bifunctional components may be extracted and used after a purification process such as a column.
• bisphenols are preferred because they provide an excellent balance between flexibility and toughness when cured, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred because of their outstanding toughness-imparting properties.
• the curing properties and heat resistance of the cured product are important, dihydroxynaphthalenes are preferred, and 2,7-dihydroxynaphthalene is particularly preferred because of its outstanding fast-curing properties.
• the moisture resistance of the cured product is important, it is preferable to use a compound containing an alicyclic structure.
• the reaction ratio of the diglycidyl ether (a1) of the dihydroxy compound having an alkylene chain or polyether chain to the aromatic hydroxy compound (a2) is preferably (a1)/(a2) from 1/1.01 to 1/5.0 (molar ratio), and more preferably (a1)/(a2) from 1/1.02 to 1/3.0 (molar ratio).
• the reaction between the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain and the aromatic hydroxy compound (a2) is preferably carried out in the presence of a catalyst.
• a catalyst various catalysts can be used, for example, alkali (earth) metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, etc., alkali metal carbonates such as sodium carbonate, potassium carbonate, etc., phosphorus compounds such as triphenylphosphine, etc., chlorides such as DMP-30, DMAP, tetramethylammonium, tetraethylammonium, tetrabutylammonium, benzyltributylammonium, bromides, iodides, quaternary ammonium salts such as chlorides such as tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium,
• Two or more of these catalysts may be used in combination.
• sodium hydroxide, potassium hydroxide, triphenylphosphine, and DMP-30 are preferred because the reaction proceeds quickly and the effect of reducing the amount of impurities is high.
• the amount of these catalysts used is not particularly limited, but it is preferable to use 0.0001 to 0.1 moles per mole of aromatic hydroxyl group in the aromatic hydroxy compound (a2).
• the form of these catalysts is also not particularly limited, and they may be used in the form of an aqueous solution or in the form of a solid.
• the reaction between the diglycidyl ether (a1) of the dihydroxy compound having an alkylene chain or polyether chain and the aromatic hydroxy compound (a2) can be carried out without a solvent or in the presence of an organic solvent.
• organic solvents that can be used include methyl cellosolve, ethyl cellosolve, toluene, xylene, methyl isobutyl ketone, dimethyl sulfoxide, propyl alcohol, and butyl alcohol.
• the amount of the organic solvent used is usually 50 to 300% by mass, preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination. In order to carry out the reaction quickly, it is preferable to use no solvent, while it is preferable to use dimethyl sulfoxide in order to reduce impurities in the final product.
• the reaction temperature for the above reaction is usually 50 to 180°C, and the reaction time is usually 1 to 30 hours. In terms of reducing impurities in the final product, a reaction temperature of 100 to 160°C is preferable.
• an antioxidant or reducing agent may be added to suppress this.
• the antioxidant is not particularly limited, but examples thereof include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing a trivalent phosphorus atom.
• the reducing agent is not particularly limited, but examples thereof include hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, or salts thereof.
• the reaction mixture can be neutralized or washed until its pH value reaches 3 to 7, preferably 5 to 7.
• the neutralization and washing can be carried out according to conventional methods.
• an acidic substance such as hydrochloric acid, sodium dihydrogen phosphate, p-toluenesulfonic acid, or oxalic acid can be used as a neutralizing agent.
• the solvent can be distilled off under reduced pressure and heating, if necessary, to concentrate the product and obtain a hydroxy compound.
• a hydroxy compound having both the structural unit X and the structural unit Y can be obtained.
• a preferred structure is, for example, a compound represented by the following structural formula.
• ran represents a random bond
• R' is a divalent hydrocarbon group having 2 to 12 carbon atoms
• n1 is an integer from 4 to 16
• n2 is the average number of repeating units and is 2 to 30
• m1 and m2 are the average number of repeating units and are each independently 0.5 to 25.
• each repeating unit present in the repeating unit may be the same or different.
• a hydroxy compound having the structural unit X can be obtained.
• a preferred structure is, for example, a compound represented by the following structural formula.
• n1 is an integer between 4 and 16
• m1 is the average number of repeats, which is between 0.5 and 25.
• a hydroxy compound having the structural unit Y can be obtained.
• a preferred structure can be, for example, a compound represented by the following structural formula.
• R' is a divalent hydrocarbon group having 2 to 12 carbon atoms
• n2 is the average number of repeating units and is 2 to 30
• m2 is the average number of repeating units and is 0.5 to 25.
• each repeating unit present in the repeating unit may be the same or different.
• the method for the glycidyl etherification reaction of the precursor (intermediate) hydroxy compound obtained above is not particularly limited, and examples include a method of reacting a phenolic hydroxyl group with epihalohydrin, and a method of olefinizing the phenolic hydroxyl group and oxidizing the carbon-carbon double bond of the olefin with an oxidizing agent.
• the method using epihalohydrin (a3) is preferred in terms of ease of obtaining the raw material and the reaction.
• An example of a method using epihalohydrin (a3) is to add 0.3 to 100 moles of epihalohydrin (a3) per mole of aromatic hydroxyl group of the hydroxy compound obtained above, and to this mixture, 0.9 to 2.0 moles of a basic catalyst per mole of aromatic hydroxyl group of the hydroxy compound are added all at once or gradually while reacting for 0.5 to 10 hours at a temperature of 20 to 120°C.
• This basic catalyst may be a solid or an aqueous solution thereof.
• an aqueous solution it may be added continuously, and water and epihalohydrin (a3) may be continuously distilled from the reaction mixture under reduced pressure or normal pressure, and then the water may be removed by liquid separation, while the epihalohydrin (a3) may be continuously returned to the reaction mixture.
• the epihalohydrin (a3) used is not particularly limited, but examples include epichlorohydrin, epibromohydrin, etc. Among these, epichlorohydrin is preferred because it is easily available.
• the basic catalyst is not particularly limited, but examples include alkaline earth metal hydroxides, alkali metal carbonates, and alkali metal hydroxides.
• alkali metal hydroxides are preferred because of their excellent catalytic activity in the epoxy resin synthesis reaction, and examples include sodium hydroxide and potassium hydroxide.
• these alkali metal hydroxides may be used in the form of an aqueous solution of about 10 to 55 mass %, or in the form of a solid.
• the reaction rate in the synthesis of the epoxy resin can be increased by using an organic solvent in combination.
• organic solvents include, but are not limited to, ketones such as acetone and methyl ethyl ketone, alcohols such as methanol, ethanol, 1-propyl alcohol, isopropyl alcohol, 1-butanol, secondary butanol, and tertiary butanol, cellosolves such as methyl cellosolve and ethyl cellosolve, ethers such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, and diethoxyethane, and aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, and dimethylformamide.
• ketones such as acetone and methyl ethyl ketone
• alcohols such as methanol, ethanol, 1-propyl alcohol, isopropyl alcohol, 1-butanol, secondary butan
• the unreacted epihalohydrin (a3) and the organic solvent used in combination are removed by distillation under heating and reduced pressure. Furthermore, in order to obtain an epoxy resin with even less hydrolyzable halogen, the obtained epoxy resin can be dissolved again in an organic solvent such as toluene, methyl isobutyl ketone, or methyl ethyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide can be added to carry out further reaction. At this time, a phase transfer catalyst such as a quaternary ammonium salt or crown ether can be present in order to improve the reaction rate.
• an organic solvent such as toluene, methyl isobutyl ketone, or methyl ethyl ketone
• an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide
• the amount used is preferably in the range of 0.1 to 3.0% by mass based on the epoxy resin used.
• the salt formed is removed by filtration, washing with water, etc., and the solvent, such as toluene or methyl isobutyl ketone, is distilled off under heating and reduced pressure to obtain a high-purity epoxy resin.
• the epoxy resin (B) contained in the epoxy resin of this embodiment may have an epoxy equivalent in the range of 100 to 300 g/eq, and is not limited in structure.
• liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, and tetramethylbiphenyl type epoxy resin, brominated epoxy resins such as brominated phenol novolac type epoxy resin, solid bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclohexyl ether type epoxy resin, etc.
• epoxy resins examples include butadiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, phenylene ether type epoxy resins, naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, aromatic hydrocarbon formaldehyde resin modified phenolic resin type epoxy resins, biphenyl modified novolac type epoxy resins, and the like. These may be used alone or in combination of two or more kinds, and it is preferable to select and use various types depending on the intended use and physical properties of the cured product.
• liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, and tetramethylbiphenyl type epoxy resin, with an epoxy equivalent of 100 to 300 g/eq. It is particularly preferable to use liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and bisphenol AD type epoxy resin, with an epoxy equivalent of 100 to 300 g/eq.
• the ratio of the epoxy resin (A) to the epoxy resin (B) is not particularly limited, but from the viewpoint of facilitating phase separation in the cured product, the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:90, preferably 80:20 to 20:80, and particularly preferably 70:30 to 30:70.
• Phase separation in the cured product results in a sea-island structure, which balances the adhesiveness and stress relaxation ability of the cured product, exerts high adhesive strength over a particularly wide temperature range, and has the effect of reducing the molding shrinkage rate before and after heat curing of the resin composition.
• the curable functional group-containing compound (C) contained in the curable resin composition of the present embodiment is a curable functional group-containing compound (C) represented by any one of the following general formulas (4-1) and (4-2).
• the furan-derived structures in formulae (4-1) and (4-2) may have a halogen atom, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amide group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group as a substituent.
• n a and n b are the average number of repetitions and each is independently 0 to 10.
• m is an integer from 1 to 4.
• Z 1 is any of the structures represented by the following formula (5)
• Z 2 is any of the structures represented by the following formulae (6A) and (6B)
• Z 3 is any of the structures represented by the following formulae (7-1) to (7-3), and each of the multiple structures present in one molecule may be the same or different.
• the aromatic ring in formula (5) may be substituted or unsubstituted, * represents a bonding point, Fg is a curable functional group, and -Fg on the naphthalene ring in the formula indicates that it may be bonded to any position.
• each Ar independently represents a structure having an unsubstituted or substituted aromatic ring
• R 1 and R 2 each independently represent a hydrogen atom, a methyl group, or an ethyl group
• R is a hydrogen atom or a methyl group
• R'
• the structural unit X represented by the formula (6-1) and the structural unit Y represented by the formula (6-2) may be bonded randomly or in blocks, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.
• n3 and n5 are average numbers of repeating units, each of which is 0.5 to 10
• n4 is an integer of 1 to 16
• each R′′ is independently a hydrogen atom, a methyl group, or an ethyl group.
• the curable functional group-containing compound (C) contained in the curable resin composition of this embodiment is characterized by being bonded by a reversible bond due to a Diels-Alder reaction between a furan structure and a maleimide structure.
• the curable functional group-containing compound (C) is incorporated into the crosslinked structure by a curing reaction based on the curable functional group.
• the curable functional group-containing compound (C) since it has reversibility even after becoming a cured product, it has high molecular mobility even in the cured product. For this reason, when the cured product is exposed to high temperatures or receives an impact, cracks occur, or it is crushed, it is easily cut at the reversible bond portion, and it exhibits easy dismantling properties.
• the reversible bond reversibly reforms in the low temperature range, including room temperature, and therefore has excellent adhesive properties.
• furan having a reactive functional group on the ring and maleimide having a reactive functional group are used.
• a specific reversible bond partial structure can be expressed by the following chemical formula. Reversible bonds can be introduced into a compound by bonding with other structural units based on the R portion in the maleimide-derived structure in the following formula, or various reactive functional groups on the ring of the furan-derived structure.
• a conjugated diene and a parent diene undergo an addition reaction to form a six-membered ring.
• Diels-Alder reaction is an equilibrium reaction
• a Retro-Diels-Alder reaction occurs at a certain temperature, resulting in dissociation (decrosslinking).
• dissociation decrosslinking
• the C-C bond of the Diels-Alder reaction unit will be preferentially broken down because the bond energy of the C-C bond is lower than that of a normal covalent bond. This makes the cured product easily dismantlable.
• the equilibrium of the C-C bond of the Diels-Alder reaction unit shifts in the direction of the bond, so an adduct (Diels-Alder reaction unit) is formed again.
• the average molecular weight (Mw) of the curable functional group-containing compound (C) is not particularly limited, but from the viewpoint of achieving both mechanical strength, flexibility, and ease of dismantling when the cured product is formed, it is preferably 500 or more and preferably 50,000 or less. Furthermore, when there are multiple reversible bonds other than between A and B, for example in the structural unit B, it is more preferable that the molecular weight per reversible bond is in the range of 300 to 10,000 from the viewpoint of ease of dismantling and remoldability of the cured product.
• a reversible bond formed by a furan structure and a maleimide structure is present at the end of the molecule.
• the terminal maleimide structure in the general formula (4-1) and the terminal furan structure in the general formula (4-2) have at least one Z 1 which is any one of the structures represented by the general formula (5), and this curable functional group contributes to the curing reaction in the curable resin composition described below.
• m is the number of Z1 in the furan-derived structure and is an integer of 1 to 4.
• it is preferably in the range of 1 to 2, and more preferably 1.
• Z 1 in the formulas (4-1) and (4-2) has a curable functional group Fg represented by the general formula (5).
• the curable functional group Fg include a hydroxyl group, an amino group, a carboxyl group, an acid anhydride group, an amide group, an imide group, a thiol group, and an ester group.
• a hydroxyl group, an amino group, a carboxyl group, and a thiol group are preferable, and a hydroxyl group and an amino group are more preferable.
• the curable functional group Fg is preferably a hydroxyl group (-OH) or an amine group (-NH 2 ).
• Z 1 in the above formulas (4-1) and (4-2) is preferably one having the following structural formula from the viewpoints of availability of raw materials and reactivity.
• curable functional group of the curable functional group-containing compound (C) according to this embodiment is a hydroxyl group
• examples of the curable functional group-containing compound (C) of the present invention include, but are not limited to, those shown below.
• R' is a divalent hydrocarbon group having 2 to 12 carbon atoms
• n is the average number of repeating units and is 0 to 10
• n1 is an integer from 4 to 16
• n2 is the average number of repeating units and is 2 to 30, and
• k1 is 0.5 to 5.
• curable functional group of the curable functional group-containing compound (C) according to this embodiment is an amino group
• examples of the curable functional group-containing compound (C) of the present invention include, but are not limited to, those shown below.
• m, n, p1, p2, and q are average values of repetitions, m is independently 0 to 25, n is 0 to 10, p1 and p2 are independently 0 to 5, and q is 0.5 to 5.
• the method for producing the curable functional group-containing compound (C) according to this embodiment is not particularly limited, and it may be produced stepwise using known reactions depending on the desired structure, and it may also be obtained by appropriately combining commercially available raw materials. Representative synthesis methods are described below.
• the general formulas (4-1) and (4-2) have two Diels-Alder reaction units in the molecule, which are addition reaction parts formed by a Diels-Alder reaction consisting of a furan structure and a maleimide structure, as reversible bonds, and can be obtained by using a maleimide compound having the structure Z1 in general formula (4-1) and a furan compound having the structure Z1 in general formula (4-2).
• the Diels-Alder reaction in which a conjugated diene such as a furan structure and a parent diene such as a maleimide structure undergo an addition reaction to form a six-membered ring, is an equilibrium reaction, and it is widely known that at temperatures higher than the temperature at which the addition reaction proceeds, the addition reaction site dissociates, returning the original conjugated diene and parent diene, resulting in a reverse reaction known as a retro-Diels-Alder reaction.
• Examples of the maleimide compound having the structure of Z1 include any of the compounds listed in the following formulas.
• phenylmaleimides having a curable functional group (Fg) are preferred in terms of curability, and monofunctional phenylmaleimides are particularly preferred in terms of the balance between reactivity, cured product properties, and ease of dismantling.
• monofunctional phenylmaleimides phenylmaleimides having a functional group at the para position are particularly preferred in terms of heat resistance.
• the furan compound having the structure of Z1 may be any of the compounds listed in the following formulae.
• the compounds shown below are particularly preferred in terms of their reactivity, cured product properties, and the adhesiveness, flexibility, and dismantling properties of the resulting cured product.
• the structures of the maleimide compounds and furan compounds mentioned above each include those having, independently of one another, a hydrogen atom, a halogen atom, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amide group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group as a substituent.
• the alkoxy group, the aralkyloxy group, the aryloxy group, the carboxy group, the alkyloxycarbonyl group, the aryloxycarbonyl group, the alkyl group, the cycloalkyl group, the aralkyl group, and the aryl group also include those having various substituents bonded to the carbon atoms they have.
• the Diels-Alder reaction may be carried out by any known method.
• the conjugated diene compound and the parent diene compound are mixed in equimolar amounts, or in some cases one of the components is mixed in excess, and the mixture is melted by heating or dissolved in a solvent, and stirred at room temperature to 110°C for 1 to 24 hours.
• the product can then be obtained directly without purification by filtration or solvent distillation, or by a commonly used isolation and purification method such as recrystallization, reprecipitation, or chromatography.
• the above “equimolar amounts of the conjugated diene compound and the parent diene compound” means that the conjugated diene structure of the conjugated diene compound and the ethylene structure of the parent diene compound are equimolar.
• the glycidyl ether group-containing compound (C) represented by the above general formula (4) when the furan compound as the conjugated diene compound has one conjugated diene structure per molecule and the maleimide compound (bismaleimide) as the parent diene compound has two maleimide structures (ethylene structures) per molecule, the above "equimolar amounts of the conjugated diene compound and the parent diene compound” means that the molar ratio of the furan compound to the maleimide compound (bismaleimide) is 2:1.
• Synthesis of sites other than the reversible bond can be performed by known methods. For example, a diglycidyl ether of an aliphatic dihydroxy compound or an aliphatic divinyl ether is reacted with an aromatic hydroxy compound to obtain a compound having a hydroxy group at the end, which is then reacted with furfuryl glycidyl ether or the like to introduce a furan structure at the end. Furthermore, a Diels-Alder reaction with a maleimide compound having a curable functional group as described above can be performed to obtain the compound represented by the general formula (4-1).
• an aromatic dihydroxy compound can be reacted with a dihalogenated alkyl compound or a dihalogenated aralkyl compound to obtain a compound having a halogenated alkyl group at the end, which can then be reacted with furfuryl alcohol or the like to introduce a furan structure at the end, and the compound can be obtained by carrying out a Diels-Alder reaction with a maleimide compound having a curable functional group as described above.
• the diglycidyl ether of the aliphatic dihydroxy compound is not particularly limited, and examples thereof include 1,11-undecanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, 1,13-tridecanediol, 1,14-tetradecanediol diglycidyl ether, 1,15-pentadecanediol diglycidyl ether, 1,16-hexadecanediol diglycidyl ether, 2-methyl-1,11-undecanediol diglycidyl ether, 3-methyl-1,11-undecanediol diglycidyl ether, and 2,6,10-trimethyl-1,11-undecanediol diglycidyl ether, which may be used alone or in combination of two or more kinds.
• compounds having a structure in which glycidyl groups are linked to both ends of an alkylene chain having 12 to 14 carbon atoms via ether groups are preferred because they provide an excellent balance between flexibility and heat resistance in the resulting cured product, and it is most preferred to use 1,12-dodecanediol diglycidyl ether, 1,13-tridecanediol, or 1,14-tetradecanediol diglycidyl ether.
• the aliphatic divinyl ether is not particularly limited, and examples thereof include divinyl ethers of linear alkylene groups such as polyethylene glycol divinyl ether, polypropylene glycol divinyl ether, polytetramethylene glycol divinyl ether, 1,3-butylene glycol divinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, and 1,10-decanediol divinyl ether, and divinyl ethers of branched alkylene groups such as neopentyl glycol divinyl ether, divinyl ethers containing a cycloalkane structure such as 1,4-cyclohexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, tricyclodecanediol divinyl ether,
• divinyl ethers with a polyether structure or a linear alkylene chain having 4 to 10 carbon atoms are preferred because they provide an excellent balance between flexibility and toughness in the resulting cured product, and it is most preferred to use polyethylene glycol divinyl ether, polypropylene glycol divinyl ether, polytetramethylene glycol divinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, or 1,10-decanediol divinyl ether.
• the aromatic hydroxy compound is not particularly limited, and examples thereof include dihydroxybenzenes such as hydroquinone, resorcin, and catechol; trihydroxybenzenes such as pyrogallol, 1,2,4-trihydroxybenzene, and 1,3,5-trihydroxybenzene; triphenylmethane-type phenols such as 4,4',4"-trihydroxytriphenylmethane; dihydroxynaphthalenes such as 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene; and dihydroxynaphthalenes subjected to a coupling reaction.
• dihydroxybenzenes such as hydroquinone, resorcin, and catechol
• trihydroxybenzenes such as pyrogallol, 1,2,4-trihydroxybenz
• tetrafunctional phenols such as 1,1'-methylenebis-(2,7-naphthalenediol), 1,1'-binaphthalene-2,2',7,7'-tetraol, and 1,1'-oxybis-(2,7-naphthalenediol); bisphenols such as bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)-1-phenylethane and bis(4-hydroxyphenyl)sulfone; 2,2'-biphenol, 4,4'-biphenol, and (1,1'-biphenyl)-3,4-diol; biphenols such as 3,3'-dimethyl-(1,1'-biphenyl)-4,4'-diol, 3-methyl-
• bifunctional phenolic compounds having a structure in which the aromatic nucleus of each of the above compounds is substituted with a methyl group, a t-butyl group, or a halogen atom as a substituent may also be used.
• the alicyclic structure-containing phenols and the Xylok-type phenolic resins may contain not only bifunctional components but also trifunctional or higher functional components at the same time, and may be used as they are, or may be used by isolating only the bifunctional components after a purification process such as a column.
• bisphenols are preferred because they provide an excellent balance between flexibility and toughness when cured, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred because of their outstanding ability to impart toughness. Furthermore, when importance is placed on the moisture resistance of the cured product, it is preferable to use phenols that contain an alicyclic structure.
• the reaction ratio of the diglycidyl ether of the aliphatic dihydroxy compound to the aromatic hydroxy compound is preferably in the range of 1/1.01 to 1/5.0 (molar ratio) of the former/latter, and from the viewpoint of providing a well-balanced combination of flexibility and heat resistance of the resulting cured product, it is preferable that (a1)/(a2) is 1/1.02 to 1/3.0 (molar ratio).
• the reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound is preferably carried out in the presence of a catalyst.
• a catalyst various catalysts can be used, for example, alkali (earth) metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, etc., alkali metal carbonates such as sodium carbonate, potassium carbonate, etc., phosphorus compounds such as triphenylphosphine, etc., chlorides such as DMP-30, DMAP, tetramethylammonium, tetraethylammonium, tetrabutylammonium, benzyltributylammonium, bromides, iodides, quaternary ammonium salts such as chlorides such as tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, benzyltributylphosphonium, bromides
• Two or more of these catalysts may be used in combination.
• sodium hydroxide, potassium hydroxide, triphenylphosphine, and DMP-30 are preferred because the reaction proceeds quickly and the amount of impurities is highly reduced.
• the amount of these catalysts used is not particularly limited, but it is preferable to use 0.0001 to 0.01 moles per mole of hydroxyl groups of the aromatic hydroxy compound.
• the form of these catalysts is also not particularly limited, and they may be used in the form of an aqueous solution or in the form of a solid.
• the reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound can be carried out without a solvent or in the presence of an organic solvent.
• organic solvents examples include methyl cellosolve, ethyl cellosolve, toluene, xylene, methyl isobutyl ketone, dimethyl sulfoxide, propyl alcohol, and butyl alcohol.
• the amount of the organic solvent used is usually 50 to 300% by mass, preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination. In order to carry out the reaction quickly, it is preferable to use no solvent, while the use of dimethyl sulfoxide is preferable in terms of reducing impurities in the final product.
• the reaction temperature for the above reaction is usually 50 to 180°C, and the reaction time is usually 1 to 10 hours. In terms of reducing impurities in the final product, a reaction temperature of 100 to 160°C is preferable.
• an antioxidant or reducing agent may be added to suppress this.
• the antioxidant is not particularly limited, but examples thereof include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing a trivalent phosphorus atom.
• the reducing agent is not particularly limited, but examples thereof include hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, or salts thereof.
• the reaction mixture can be neutralized or washed until its pH value reaches 3 to 7, preferably 5 to 7.
• the neutralization and washing can be carried out according to conventional methods.
• an acidic substance such as hydrochloric acid, sodium dihydrogen phosphate, p-toluenesulfonic acid, or oxalic acid can be used as a neutralizing agent.
• the solvent can be distilled off under reduced pressure and heating, if necessary, to concentrate the product and obtain the compound.
• the reaction ratio of the aliphatic divinyl ether and the aromatic hydroxy compound is preferably in the range of 1/1.01 to 1/5.0 (molar ratio) for the former/the latter, and from the viewpoint of providing a well-balanced combination of flexibility and heat resistance of the resulting cured product, it is preferable that (a1)/(a2) is 1/1.02 to 1/3.0 (molar ratio).
• catalysts that can be used here include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, organic acids such as toluenesulfonic acid, methanesulfonic acid, xylenesulfonic acid, trifluoromethanesulfonic acid, oxalic acid, formic acid, trichloroacetic acid, and trifluoroacetic acid, and Lewis acids such as aluminum chloride, iron chloride, tin chloride, gallium chloride, titanium chloride, aluminum bromide, gallium bromide, boron trifluoride ether complex, and boron trifluoride phenol complex.
• inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid
• organic acids such as toluenesulfonic acid, methanesulfonic acid, xylenesulfonic acid, trifluoromethanesulfonic acid, oxa
• the amount of catalyst used is usually in the range of 10 ppm to 1% by weight based on the mass of the divinyl ether compound. In this case, it is preferable to select the type and amount of catalyst to avoid the nucleation reaction of the vinyl group to the aromatic ring.
• the reaction between the aliphatic divinyl ether and the aromatic hydroxy compound can be carried out without a solvent or in the presence of an organic solvent.
• organic solvent include aromatic organic solvents such as benzene, toluene, and xylene; ketone organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and alcohol organic solvents such as methanol, ethanol, isopropyl alcohol, and normal butanol.
• the amount of the organic solvent used is usually 50 to 300% by mass, and preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination.
• the reaction temperature for the above reaction is usually 50 to 150°C, and the reaction time is usually 0.5 to 10 hours. In this case, it is preferable to carry out the reaction in an oxygen atmosphere in order to prevent self-polymerization of the vinyl ether group.
• the compound having a hydroxyl group at the end thus obtained is reacted with furfuryl glycidyl ether or the like.
• sodium hydroxide, potassium hydroxide, potassium carbonate, etc. can be used as a catalyst, and toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, dimethylformamide, etc. can be used as a solvent.
• the reaction temperature is room temperature to 200°C, and the reaction time is 1 to 24 hours.
• the catalyst is then removed by filtration, etc., and the target compound can be obtained by extraction, solvent removal, etc.
• the Diels-Alder reaction of this compound is as described above.
• the aliphatic hydroxy compound is not particularly limited, and examples thereof include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, and 1,16-hexadecanediol.
• diols examples include 2-methyl-1,11-undecanediol, 3-methyl-1,11-undecanediol, 2,6,10-trimethyl-1,11-undecanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polypentamethylene glycol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, and polyheptamethylene glycol diglycidyl ether. These may be used alone or in combination of two or more.
• dihydroxy compounds with a polyether structure or a linear alkylene chain having 12 to 14 carbon atoms it is preferable to use dihydroxy compounds with a polyether structure or a linear alkylene chain having 12 to 14 carbon atoms, as they provide an excellent balance between flexibility and heat resistance in the resulting cured product, and it is most preferable to use polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,12-dodecanediol, 1,13-tridecanediol, or 1,14-tetradecanediol.
• the dihalogenated alkyl compound is not particularly limited, and examples thereof include 1,4-dichlorobutane, 1,5-dichloropentane, 1,6-dichlorohexane, 1,7-dichloroheptane, 1,8-dichlorooctane, 1,9-dichlorononane, 1,10-dichlorodecane, 1,11-dichloroundecane, 1,12-dichlorododecane, 1,4-dibromobutane, 1,5-dibromopentane, 1,6-dibromohexane, 1,7-dibromoheptane, 1,8-dibromooctane, 1,9-dibromononane, 1,10-dibromodecane, 1,11-dibromoundecane, and 1,12-dibromododecane. These compounds may be used alone or in combination of two or more.
• the dihalogenated aralkyl compound is not particularly limited, and examples thereof include dichloroxylene, dichloromethylbiphenyl, dibromoxylene, dibromomethylbiphenyl, etc., and may be used alone or in combination of two or more kinds.
• the reaction between the aromatic dihydroxy compound and the dihalogenated alkyl compound or dihalogenated aralkyl compound is preferably carried out in the presence of a catalyst.
• a catalyst can be used, including, for example, alkali (earth) metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide, and alkali metal carbonates such as sodium carbonate and potassium carbonate. Two or more of these catalysts may be used in combination.
• sodium hydroxide, potassium hydroxide, and potassium carbonate are preferred because the reaction proceeds quickly and they are highly effective in reducing the amount of impurities.
• the amount of these catalysts used is not particularly limited, but it is preferable to use 0.0001 to 10 moles per mole of hydroxyl groups of the aromatic hydroxy compound.
• the form of these catalysts is also not particularly limited, and they may be used in the form of an aqueous solution or in the form of a solid.
• the reaction between the aromatic dihydroxy compound and the dihalogenated alkyl compound or dihalogenated aralkyl compound can be carried out without a solvent or in the presence of an organic solvent.
• organic solvents examples include toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, and dimethylformamide.
• the amount of organic solvent used is usually 50 to 300% by mass, preferably 100 to 1000% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination.
• the reaction temperature for the above reaction is usually room temperature to 150°C, and the reaction time is usually 1 to 24 hours. From the viewpoint of reducing impurities in the final product, the reaction temperature is preferably room temperature to 100°C.
• the compound having a halogenated alkyl group at the end thus obtained is reacted with furfuryl alcohol or the like.
• Sodium hydroxide, potassium hydroxide, potassium carbonate, or the like can be used as a catalyst, and toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, dimethylformamide, or the like can be used as a solvent.
• the reaction temperature is room temperature to 200°C, and the reaction time is 1 to 24 hours.
• the catalyst is then removed by filtration, etc., and the target compound can be obtained by extraction, solvent removal, etc.
• the Diels-Alder reaction of this compound is as described above.
• the thermally expandable particles (D) contained in the curable resin composition of the present embodiment may be made of an inorganic material or an organic material.
• An example of an inorganic material is the thermally expandable graphite provided in JP-A-2000-44219.
• An example of an organic material is a thermally expandable microcapsule made by microencapsulating a volatile expanding agent that becomes gaseous at a temperature below its softening point using a thermoplastic polymer as an outer shell.
• thermally expandable microcapsules made of an organic material from the viewpoint of uniform dispersion and excellent electrical insulation properties when made into a curable resin composition.
• thermally expandable graphite from the viewpoint of the heat resistance durability and electrical conductivity of the expandable particles.
• Thermal expansion microcapsules A method for producing the thermally expandable microcapsules is provided in Japanese Patent Publication No. 42-26524, but from the viewpoint of thermally curing the epoxy resin in this embodiment, it is preferable that the microcapsules have heat resistance. Methods for producing heat-resistant thermally expandable microcapsules are provided in, for example, WO99/46320, WO99/43758, JP-A 2002-226620, etc.
• the thermally expandable microcapsules to have a shell polymer formed by polymerizing a nitrile monomer and a monomer having a carboxyl group as essential components.
• a monomer having an amide group or a monomer having a cyclic structure in the side chain is also preferable to use.
• the shell polymer is adjusted by appropriately mixing a polymerization initiator with the above-mentioned components.
• a polymerization initiator known polymerization initiators such as peroxides and azo compounds can be used.
• peroxides and azo compounds can be used.
• azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxide, 2,2'-azobis(2,4-dimethylvaleronitrile), etc. are listed.
• an oil-soluble polymerization initiator that is soluble in the polymerizable monomer used is used.
• the glass transition temperature (Tg) of the polymer constituting the outer shell of the thermally expandable microcapsule is desirably 120°C or higher.
• the Tg of the polymer can be calculated from the Tg of each homopolymer of the constituent monomers. It can also be measured by differential scanning calorimetry (DSC) or the like.
• the blowing agent contained within the microcapsules is a substance that becomes gaseous below the softening point of the shell polymer, and known substances are used. Examples include propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, nonane, decane, petroleum ether, methane halides, low boiling point liquids such as tetraalkylsilanes, and compounds such as AIBN that decomposes thermally when heated to become gaseous.
• the blowing agent is selected as needed depending on the temperature range in which the capsules are desired to be foamed. The above blowing agents are used alone or in a mixture of two or more types.
• fluorine-based compounds such as HCF, HCFC, HFC, and HFE, commonly known as fluorocarbons, fluoroethers, etc. are also given as examples, but their use should be avoided in the current social situation due to concerns about the destruction of the ozone layer and global warming.
• conventional methods for producing thermally expandable microcapsules are generally used. That is, inorganic fine particles such as silica, magnesium hydroxide, calcium phosphate, and aluminum hydroxide are used as dispersion stabilizers in aqueous systems.
• condensation products of diethanolamine and aliphatic dicarboxylic acids, polyvinylpyrrolidone, methylcellulose, polyethylene oxide, polyvinyl alcohol, various emulsifiers, etc. are used as dispersion stabilization assistants.
• the average particle size of the thermally expandable microcapsules is 1 to 500 ⁇ m, preferably 3 to 100 ⁇ m, and more preferably 5 to 50 ⁇ m.
• the average particle size of the thermally expandable microcapsules can be measured, for example, by using a particle size distribution diameter measuring device (LA-950, manufactured by HORIBA) to measure the volume average particle size.
• Thermal Expandable Graphite A method for producing the thermally expandable graphite is provided in JP 2000-44219 A, etc., but from the viewpoint of thermally curing the epoxy resin in this embodiment, it is preferable that the graphite has heat resistance.
• a method for producing heat-resistant thermally expandable graphite is provided in, for example, JP 2012-193053 A, etc.
• Thermal expandable graphite is usually obtained by treating graphite such as natural graphite, pyrolytic graphite, or kish graphite with a mixture of concentrated sulfuric acid and a strong oxidizing agent (hereinafter referred to as acid treatment) to generate intercalation compounds between the graphite layers, followed by washing with water, filtering, and drying.
• acid treatment a mixture of concentrated sulfuric acid and a strong oxidizing agent
• Common acid treatment methods are based on concentrated sulfuric acid, such as concentrated sulfuric acid and nitric acid, concentrated sulfuric acid and potassium permanganate, concentrated sulfuric acid and perchloric acid, or concentrated sulfuric acid and hydrogen peroxide.
• concentrated sulfuric acid such as concentrated sulfuric acid and nitric acid, concentrated sulfuric acid and potassium permanganate, concentrated sulfuric acid and perchloric acid, or concentrated sulfuric acid and hydrogen peroxide.
• a method that uses only fuming nitric acid is also known.
• Thermal expandable graphite is selected based on the range of the longest diameter of the particles. For this reason, commercially available expandable graphite is expressed in terms of particle size instead of longest diameter. Specifically, commercially available expandable graphite is classified using a sieve, and the properties of the expandable graphite product are displayed based on the mesh size of the sieve, indicating the particle size of the product and the percentage of particles that pass through the sieve.
• the preferred particle size of the thermally expandable graphite used as the thermally expandable particles (D) in this embodiment is 20 to 300 mesh, and more preferably 30 to 200 mesh.
• the average particle size of the thermally expandable particles (D) is 1 to 500 ⁇ m, preferably 3 to 100 ⁇ m, and more preferably 5 to 50 ⁇ m.
• the thermally expandable particles (D) may be mixed directly with the epoxy resin (A) and the epoxy resin (B), or may be mixed with the epoxy resin (A) and the epoxy resin (B) using a master batch in which the thermally expandable particles (D) are dispersed in a high concentration in various resins.
• thermally expandable particles (D) commercially available products can also be used.
• Commercially available products include, for example, Matsumoto Yushi Pharmaceutical Co., Ltd.'s Microspheres (product names: F-20D, F-30D, F-40D, FN-100D, FN-100MD, FN-100SD, FN-100SSD, FN-180D, FN-180SD, FN-180SSD, F-190D, F-260D), Kureha Co., Ltd.'s Microspheres (product names: H850D, H880D, S2340D, S2640D), Fuji Kogyo Co., Ltd.'s Microspheres (product names: H850D, H880D, S2340D, S2640D), and Fuji Kogyo Co., Ltd.'s Microspheres (product names: H850D, H880D, S2340D, S2640D).
• Examples include expanded graphite manufactured by Ito Graphite Co., Ltd. (product names: EXP-50S120K, EXP-50S150), expanded graphite manufactured by Ito Graphite Co., Ltd. (product names: 953240L, 9550250), and thermally expandable graphite manufactured by Air Water Co., Ltd. (product names: 50LTE-U, MZ-260, CA-60, SS-3, SS-3LA). It is preferable to appropriately select particles that do not thermally expand at the curing temperature of the curable resin composition, but do thermally expand at the heating temperature during dismantling.
• the use ratio of the thermally expandable particles (D) is preferably in the range of 3 to 40 parts by mass, more preferably in the range of 5 to 30 parts by mass, even more preferably in the range of 6 to 20 parts by mass, and particularly preferably in the range of 7 to 15 parts by mass, per 100 parts by mass of the epoxy resin (A) and the epoxy resin (B) in total, from the viewpoint of exerting the effect of sufficiently expanding and reducing adhesiveness when dismantled after use without impairing the adhesiveness when the curable resin composition of this embodiment is cured or the flexibility of the cured product.
• the curable resin composition of this embodiment may further contain a curing agent for epoxy resins that does not belong to the curable functional group-containing compound (C).
• the curing agents that can be used here include various known curing agents for epoxy resins, such as amine compounds that do not belong to the curable functional group-containing compounds (C), acid anhydrides, amide compounds, hydroxyl group-containing compounds that do not belong to the curable functional group-containing compounds (C), carboxylic acid compounds, and thiol compounds.
• the amine compounds include, for example, trimethylenediamine, ethylenediamine, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenetriamine, triethylenediamine, dipropylenediamine, N,N,N',N'-tetramethylpropylenediamine, tetramethylenediamine, pentanediamine, hexamethylenediamine, trimethylhexamethylenediamine, N,N,N',N'-tetramethylhexamethylenediamine, N,N-dimethylcyclohexylamine, diethylenetriamine, triethylenetetramine, tetramethylhexamethylenediamine ...
• Aliphatic amine compounds such as triethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, 1,4-diazabicyclo(2,2,2)octane (triethylenediamine), polyoxyethylenediamine, polyoxypropylenediamine, bis(2-dimethylaminoethyl)ether, dimethylaminoethoxyethoxyethanol, triethanolamine, dimethylaminohexanol, benzylmethylamine, dimethylbenzylamine, m-xylenediamine, and ⁇ -methylbenzylmethylamine;
• Alicyclic and heterocyclic amine compounds such as piperidine, piperazine, menthanediamine, isophoronediamine, methylmorpholine, ethylmorpholine, N,N',N"-tris(dimethylaminopropyl)hexahydro-s-triazine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxyspiro(5,5)undecane adduct, N-aminoethylpiperazine, trimethylaminoethylpiperazine, bis(4-aminocyclohexyl)methane, N,N'-dimethylpiperazine, and 1,8-diazabicyclo-[5.4.0]-undecene (DBU);
• DBU 1,8-diazabicyclo-[5.4.0]-undecene
• Aromatic amine compounds such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, pyridine, picoline, etc.;
• modified amine compounds such as epoxy compound-added polyamines, Michael-added polyamines, Mannich-added polyamines, thiourea-added polyamines, ketone-blocked polyamines, dicyandiamide, guanidine, organic acid hydrazides, diaminomaleonitrile, aminimides, boron trifluoride-piperidine complexes, and boron trifluoride-monoethylamine complexes.
• modified amine compounds such as epoxy compound-added polyamines, Michael-added polyamines, Mannich-added polyamines, thiourea-added polyamines, ketone-blocked polyamines, dicyandiamide, guanidine, organic acid hydrazides, diaminomaleonitrile, aminimides, boron trifluoride-piperidine complexes, and boron trifluoride-monoethylamine complexes.
• acid anhydrides examples include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, maleic polypropylene glycol anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.
• the hydroxyl group-containing compounds include bisphenols such as bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)-1-phenylethane, and bis(4-hydroxyphenyl)sulfone, phenol novolac resins, cresol novolac resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resins, dicyclopentadiene phenol adduct resins, phenol aralkyl resins (Zylok resins), naphthol aralkyl resins, trimethylolmethane resins, tetramethylolmethane resins, and tetramethylolmethane resins.
• bisphenols such as bis(4-hydroxyphenyl)methane, 2,2-bis
• polyhydric phenol compounds include laphenylolethane resin, naphthol novolak resin, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin (a polyhydric phenol compound in which the phenol nucleus is linked by a bismethylene group), biphenyl-modified naphthol resin (a polyhydric naphthol compound in which the phenol nucleus is linked by a bismethylene group), aminotriazine-modified phenol resin (a polyhydric phenol compound in which the phenol nucleus is linked by melamine, benzoguanamine, etc.), and alkoxy group-containing aromatic ring-modified novolak resin (a polyhydric phenol compound in which the phenol nucleus and the alkoxy group-containing aromatic ring are linked by formaldehyde).
• biphenyl-modified phenol resin a polyhydric phenol compound in which the
• Examples of the amide-based compounds include dicyandiamide and polyamidoamine.
• Examples of the polyamidoamine include those obtained by reacting an aliphatic dicarboxylic acid such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, or azelaic acid, or a carboxylic acid compound such as a fatty acid or dimer acid, with an aliphatic polyamine or a polyamine having a polyoxyalkylene chain.
• carboxylic acid compound examples include carboxylic acid polymers such as carboxylic acid-terminated polyester, polyacrylic acid, and maleic acid-modified polypropylene glycol.
• the thiol compound preferably contains two or more thiol groups in one molecule.
• Examples include 3,3'-dithiodipropionic acid, trimethylolpropane tris(thioglycolate), pentaerythritol tetrakis(thioglycolate), ethylene glycol dithioglycolate, 1,4-bis(3-mercaptobutyryloxy)butane, tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptopropionate), 1,3,4,6-tetrakis(2-mercaptoethyl)g
• amine compounds particularly dicyandiamide
• solid phenol compounds are preferred in terms of the heat resistance of the cured product.
• aliphatic amines and thiol compounds are preferred in terms of low-temperature curing.
• the amounts of epoxy resin and curing agent used are not particularly limited, but in terms of the good mechanical properties of the resulting cured product, it is preferable to use an amount that results in 0.4 to 1.5 equivalents of active groups that can react with epoxy groups, including the hydroxyl group-containing cured product of the present invention, per 1 equivalent of epoxy groups in the resin composition.
• the curable resin composition of the present embodiment may further contain other epoxy resins not belonging to the epoxy resin (A) and the epoxy resin (B) of the present embodiment in combination within a range that does not impair the effects of the present embodiment.
• the total amount of the epoxy resin (A) and the epoxy resin (B) in the curable resin composition of the present embodiment is preferably 30 mass% or more, particularly preferably 40 mass% or more, of the total epoxy resins.
• epoxy resins that can be used in combination are not limited in any way other than being epoxy resin (A) or epoxy resin (B), and include, for example, liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, and tetramethylbiphenyl type epoxy resin; brominated epoxy resins such as brominated phenol novolac type epoxy resin; solid bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenylmethane epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, phenylene ether type epoxy resins, naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, naphthol aralky
• the concentration of the reversible bonds in the curable resin composition of this embodiment is preferably 0.10 mmol/g or more relative to the total mass of the curable components in the curable resin composition. With this configuration, the adhesiveness, flexibility, and dismantling properties of the cured product obtained from the curable resin composition are all further improved.
• the concentration of the reversible bonds is more preferably 0.10 to 3.00 mmol/g, and even more preferably 0.15 to 2.00 mmol/g.
• the concentration of the reversible bonds in total is preferably 0.10 mmol/g or more relative to the total mass of the curable components in the curable resin composition, more preferably 0.10 to 3.00 mmol/g, and even more preferably 0.15 to 2.00 mmol/g.
• the concentration of the reversible bond can be appropriately selected based on the glass transition temperature defined by the tan ⁇ peak top of the target cured product in a dynamic viscoelasticity measuring device (DMA).
• the glass transition temperature of the cured product when used as a guideline, if the glass transition temperature of the cured product is near room temperature, sufficient adhesiveness, flexibility, and dismantling functions are likely to be expressed even at the low concentration side of the preferred range.
• the glass transition temperature of the target cured product exceeds 100°C as a guideline, the functions are likely to be expressed at the high concentration side of the preferred range.
• the temperature range exceeding the glass transition temperature measured by DMA molecular mobility is generally high, and sufficient adhesiveness, flexibility, and dismantling functions are likely to be expressed even at a low concentration of the curable functional group-containing compound (C).
• the effect of expressing the adhesiveness, flexibility, and dismantling functions can be adjusted by appropriately adjusting the aging temperature for curing and the heating temperature for dismantling.
• the relationship between the glass transition temperature of the cured product and the concentration of the reversible bond is not limited to these.
• the ratio of the total number of glycidyl ether groups in the curable resin composition of this embodiment to the total number of active groups capable of reacting with these glycidyl ether groups is not particularly limited, but in terms of good mechanical properties of the resulting cured product, it is preferable that the amount of active groups capable of reacting with glycidyl ether groups is 0.4 to 1.5 equivalents per equivalent of the total number of glycidyl ether groups in the resin composition.
• the curable resin composition of the present embodiment may contain a curing accelerator.
• a curing accelerator Various types can be used, including, for example, urea compounds, phosphorus compounds, tertiary amines, imidazole, imidazoline, organic acid metal salts, Lewis acids, and amine complex salts.
• urea compounds particularly 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), are preferred because of their excellent workability and low-temperature curing properties.
• triphenylphosphine When used as a semiconductor encapsulating material, triphenylphosphine is preferred as a phosphorus compound, and 1,8-diazabicyclo-[5.4.0]-undecene is preferred as a tertiary amine because of their excellent curing properties, heat resistance, electrical properties, and moisture resistance reliability.
• Examples of the phosphorus compound include alkyl phosphines such as ethylphosphine and butylphosphine, primary phosphines such as phenylphosphine, dialkyl phosphines such as dimethylphosphine and dipropylphosphine, secondary phosphines such as diphenylphosphine and methylethylphosphine, and tertiary phosphines such as trimethylphosphine, triethylphosphine, and triphenylphosphine.
• alkyl phosphines such as ethylphosphine and butylphosphine
• primary phosphines such as phenylphosphine
• dialkyl phosphines such as dimethylphosphine and dipropylphosphine
• secondary phosphines such as diphenylphosphine and methylethy
• the imidazole may, for example, be imidazole, 1-methylimidazole, 2-methylimidazole, 3-methylimidazole, 4-methylimidazole, 5-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 3-ethylimidazole, 4-ethylimidazole, 5-ethylimidazole, 1-n-propylimidazole, 2-n-propylimidazole, 1-isopropylimidazole, 2- Isopropylimidazole, 1-n-butylimidazole, 2-n-butylimidazole, 1-isobutylimidazole, 2-isobutylimidazole, 2-undecyl-1H-imidazole, 2-heptadecyl-1H-imidazole, 1,2-dimethylimidazole, 1,3-dimethylimidazole, 2,4-dimethylimidazole, 2-e
• imidazoline compound examples include 2-methylimidazoline and 2-phenylimidazoline.
• urea compounds examples include p-chlorophenyl-N,N-dimethylurea, 3-phenyl-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-N,N-dimethylurea, and N-(3-chloro-4-methylphenyl)-N',N'-dimethylurea.
• thermosetting and thermoplastic resins The curable resin composition of the present embodiment may be used in combination with other thermosetting resins or thermoplastic resins within a range that does not impair the effects of the present embodiment.
• thermosetting resins include, for example, cyanate ester resins, resins having a benzoxazine structure, active ester resins, vinylbenzyl compounds, acrylic compounds, copolymers of styrene and maleic anhydride, etc.
• the amount used there are no particular restrictions on the amount used as long as it does not inhibit the effects of this embodiment, but it is preferable for the amount to be in the range of 1 to 50 parts by mass per 100 parts by mass of the curable resin composition.
• cyanate ester resin examples include bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, bisphenol S type cyanate ester resin, bisphenol sulfide type cyanate ester resin, phenylene ether type cyanate ester resin, naphthylene ether type cyanate ester resin, biphenyl type cyanate ester resin, tetramethylbiphenyl type cyanate ester resin, polyhydroxynaphthalene type cyanate ester resin, phenol novolac type cyanate ester resin, cresol novolac type cyanate ester resin, triphenyl
• the cyanate ester resin include tetraphenylethane type cyanate ester resin, dicyclopentadiene-phenol addition reaction type cyanate ester resin, phenol aralkyl type cyanate ester resin, naphthol novolac type cyanate ester resin, naphthol a
• cyanate ester resins it is preferable to use bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, polyhydroxynaphthalene type cyanate ester resin, naphthylene ether type cyanate ester resin, and novolac type cyanate ester resin, in that they provide a cured product with excellent heat resistance, and dicyclopentadiene-phenol addition reaction type cyanate ester resin is preferable in that they provide a cured product with excellent dielectric properties.
• resins having a benzoxazine structure include reaction products of bisphenol F, formalin, and aniline (F-a type benzoxazine resin), reaction products of diaminodiphenylmethane, formalin, and phenol (P-d type benzoxazine resin), reaction products of bisphenol A, formalin, and aniline, reaction products of dihydroxydiphenyl ether, formalin, and aniline, reaction products of diaminodiphenyl ether, formalin, and phenol, reaction products of dicyclopentadiene-phenol adduct resin, formalin, and aniline, reaction products of phenolphthalein, formalin, and aniline, and reaction products of diphenyl sulfide, formalin, and aniline. These may be used alone or in combination of two or more.
• the active ester resin is not particularly limited, but generally, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferably used.
• the active ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound.
• an active ester resin obtained from a carboxylic acid compound or its halide and a hydroxy compound is preferred, and an active ester resin obtained from a carboxylic acid compound or its halide and a phenol compound and/or a naphthol compound is more preferred.
• the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, etc., or halides thereof.
• phenol compounds or naphthol compounds include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, dihydroxydiphenyl ether, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, ⁇ -naphthol, ⁇ -naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, and dicyclopentadiene-phenol adduct resins.
• active ester resins that are preferred include active ester resins containing a dicyclopentadiene-phenol adduct structure, active ester resins containing a naphthalene structure, active ester resins which are acetylated phenol novolac, and active ester resins which are benzoylated phenol novolac.
• active ester resins containing a dicyclopentadiene-phenol adduct structure and active ester resins containing a naphthalene structure are more preferred because of their excellent ability to improve peel strength.
• novolac resins addition polymerization resins of alicyclic diene compounds such as dicyclopentadiene and phenol compounds, modified novolac resins of hydroxyl group-containing compounds and alkoxy group-containing aromatic compounds, phenol aralkyl resins (Zylok resins), naphthol aralkyl resins, trimethylolmethane resins, tetraphenylolethane resins, biphenyl-modified phenol resins, biphenyl-modified naphthol resins, aminotriazine-modified phenol resins, and various vinyl polymers may be used in combination.
• novolak resins include polymers obtained by reacting hydroxyl-containing compounds such as phenol, phenylphenol, resorcinol, biphenyl, bisphenols such as bisphenol A and bisphenol F, naphthol, and dihydroxynaphthalene with aldehyde compounds under acid catalyst conditions.
• the various vinyl polymers mentioned above include homopolymers of vinyl compounds such as polyhydroxystyrene, polystyrene, polyvinylnaphthalene, polyvinylanthracene, polyvinylcarbazole, polyindene, polyacenaphthylene, polynorbornene, polycyclodecene, polytetracyclododecene, polynortricyclene, and poly(meth)acrylate, or copolymers thereof.
• vinyl compounds such as polyhydroxystyrene, polystyrene, polyvinylnaphthalene, polyvinylanthracene, polyvinylcarbazole, polyindene, polyacenaphthylene, polynorbornene, polycyclodecene, polytetracyclododecene, polynortricyclene, and poly(meth)acrylate, or copolymers thereof.
• Thermoplastic resins are resins that can be melt-molded by heating. Specific examples include polyethylene resin, polypropylene resin, polystyrene resin, rubber-modified polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene terephthalate resin, ethylene vinyl alcohol resin, cellulose acetate resin, ionomer resin, polyacrylonitrile resin, polyamide resin, polyacetal resin, polybutylene terephthalate resin, polylactic acid resin, polyphenylene ether resin, modified polyphenylene ether resin, polycarbonate resin, polysulfone resin, polyphenylene sulfide resin, polyetherimide resin, polyethersulfone resin, polyarylate resin, thermoplastic polyimide resin, polyamideimide resin, polyether
• the blending ratio of the curable functional group-containing compound (C) of this embodiment to the other resins can be set as desired depending on the application, but in terms of excellent adhesion, flexibility, and dismantling properties when made into a cured product, it is preferable that the other resins be 0.5 to 100 parts by mass per 100 parts by mass of the curable functional group-containing compound (C) of this embodiment.
• Non-halogen flame retardants When the curable resin composition of the present embodiment is used for applications requiring high flame retardancy, a non-halogen flame retardant that contains substantially no halogen atoms may be blended therein.
• non-halogen flame retardants examples include phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organic metal salt-based flame retardants. There are no limitations on their use, and they may be used alone or in combination with multiple flame retardants of the same type.
• the phosphorus-based flame retardant may be either inorganic or organic.
• inorganic compounds include red phosphorus, ammonium phosphates such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and ammonium polyphosphate, and inorganic nitrogen-containing phosphorus compounds such as phosphoric acid amide.
• the red phosphorus is preferably surface-treated to prevent hydrolysis and the like.
• surface treatment methods include (i) a method of coating with an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, bismuth oxide, bismuth hydroxide, bismuth nitrate, or a mixture of these; (ii) a method of coating with a mixture of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, and a thermosetting resin such as a phenolic resin; and (iii) a method of doubly coating with a thermosetting resin such as a phenolic resin on top of a coating of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, etc.
• an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, etc.
• the organic phosphorus compounds include, for example, general-purpose organic phosphorus compounds such as phosphate ester compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphorane compounds, and organic nitrogen-containing phosphorus compounds, as well as cyclic organic phosphorus compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(2,7-dihydroxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and derivatives thereof reacted with compounds such as epoxy resins and phenolic resins.
• general-purpose organic phosphorus compounds such as phosphate ester compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphorane compounds, and organic nitrogen-containing phosphorus compounds,
• the amount of these phosphorus-based flame retardants to be blended is appropriately selected depending on the type of phosphorus-based flame retardant, the other components of the resin composition, and the desired level of flame retardancy.
• red phosphorus when used as a non-halogen flame retardant, it is preferably blended in the range of 0.1 to 2.0 parts by mass, and when an organic phosphorus compound is used, it is preferably blended in the range of 0.1 to 10.0 parts by mass, and more preferably in the range of 0.5 to 6.0 parts by mass, per 100 parts by mass of the resin composition containing all of the non-halogen flame retardants and other fillers and additives.
• the phosphorus-based flame retardant may be used in combination with hydrotalcite, magnesium hydroxide, boron compounds, zirconium oxide, black dyes, calcium carbonate, zeolite, zinc molybdate, activated carbon, etc.
• the nitrogen-based flame retardant may, for example, be a triazine compound, a cyanuric acid compound, an isocyanuric acid compound, or a phenothiazine, with triazine compounds, cyanuric acid compounds, and isocyanuric acid compounds being preferred.
• the triazine compounds include, for example, melamine, acetoguanamine, benzoguanamine, melon, melam, succinoguanamine, ethylenedimelamine, melamine polyphosphate, triguanamine, etc., as well as (1) aminotriazine sulfate compounds such as guanylmelamine sulfate, melem sulfate, and melam sulfate, (2) co-condensates of phenols such as phenol, cresol, xylenol, butylphenol, and nonylphenol with melamines such as melamine, benzoguanamine, acetoguanamine, and formguanamine and formaldehyde, (3) mixtures of the co-condensates of (2) with phenolic resins such as phenol formaldehyde condensates, and (4) compounds obtained by further modifying (2) and (3) with tung oil, isomerized linseed oil, etc.
• cyanuric acid compound examples include cyanuric acid, melamine cyanurate, etc.
• the amount of the nitrogen-based flame retardant to be blended is appropriately selected depending on the type of nitrogen-based flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferable to blend in an amount of 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the resin composition containing the non-halogen flame retardant and all other fillers and additives.
• metal hydroxides, molybdenum compounds, etc. may also be used in combination.
• the silicone-based flame retardant can be any organic compound containing silicon atoms, and examples of such compounds include silicone oil, silicone rubber, and silicone resin.
• the amount of silicone-based flame retardant to be used is appropriately selected depending on the type of silicone-based flame retardant, the other components of the resin composition, and the desired level of flame retardancy. It is preferable to use 0.05 to 20 parts by mass of the silicone-based flame retardant in 100 parts by mass of the resin composition containing the non-halogen flame retardant and all other fillers and additives.
• a molybdenum compound, alumina, etc. may also be used in combination.
• inorganic flame retardant examples include metal hydroxides, metal oxides, metal carbonate compounds, metal powders, boron compounds, and low-melting glass.
• metal hydroxide examples include aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, zirconium hydroxide, etc.
• metal oxide examples include zinc molybdate, molybdenum trioxide, zinc stannate, tin oxide, aluminum oxide, iron oxide, titanium oxide, manganese oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide, chromium oxide, nickel oxide, copper oxide, and tungsten oxide.
• metal carbonate compounds examples include zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, basic magnesium carbonate, aluminum carbonate, iron carbonate, cobalt carbonate, and titanium carbonate.
• metal powder examples include aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, and tin.
• Examples of the boron compound include zinc borate, zinc metaborate, barium metaborate, boric acid, and borax.
• low melting point glass examples include glassy compounds such as Seapley (Boxy Brown), hydrated glass SiO2-MgO-H2O, PbO-B2O3, ZnO-P2O5-MgO, P2O5-B2O3-PbO-MgO, P-Sn-O-F, PbO-V2O5-TeO2, Al2O3-H2O, and lead borosilicate.
• glassy compounds such as Seapley (Boxy Brown), hydrated glass SiO2-MgO-H2O, PbO-B2O3, ZnO-P2O5-MgO, P2O5-B2O3-PbO-MgO, P-Sn-O-F, PbO-V2O5-TeO2, Al2O3-H2O, and lead borosilicate.
• the amount of inorganic flame retardant to be blended is appropriately selected depending on the type of inorganic flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferable to blend in an amount of 0.05 to 20 parts by mass, and more preferably 0.5 to 15 parts by mass, per 100 parts by mass of the resin composition containing the non-halogen flame retardant and all other fillers and additives.
• organometallic salt flame retardants examples include ferrocene, acetylacetonate metal complexes, organometallic carbonyl compounds, organocobalt salt compounds, organosulfonic acid metal salts, and compounds in which a metal atom is ionic- or coordinate-bonded to an aromatic compound or heterocyclic compound.
• the amount of the organometallic salt flame retardant to be blended is appropriately selected depending on the type of organometallic salt flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferable to blend in an amount of 0.005 to 10 parts by mass per 100 parts by mass of the resin composition containing the non-halogen flame retardant and all other fillers, additives, etc.
• the curable resin composition of the present embodiment may contain a filler that does not belong to the thermally expandable particles (D) of the present embodiment.
• the filler include inorganic fillers and organic fillers.
• the inorganic filler include inorganic fine particles.
• Inorganic fine particles include, for example, those with excellent heat resistance, such as alumina, magnesia, titania, zirconia, and silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, and ultrafine amorphous silica, etc.); those with excellent thermal conductivity, such as boron nitride, aluminum nitride, alumina oxide, titanium oxide, magnesium oxide, zinc oxide, silicon oxide, and diamond; those with excellent electrical conductivity, such as metal fillers and/or metal-coated fillers using metals or alloys (e.g., iron, copper, magnesium, aluminum, gold, silver, platinum, zinc, manganese, and stainless steel); and those with excellent barrier properties, such as minerals such as mica, clay, kaolin, talc, zeolite, wollastonite, and smectite, potassium titanate, magnesium sulfate, sepiolite, and
• silica fine particles such as powdered silica and colloidal silica can be used without any particular limitation.
• powdered silica fine particles include Aerosil 50 and 200 manufactured by Nippon Aerosil Co., Ltd., Sildex H31, H32, H51, H52, H121, and H122 manufactured by Asahi Glass Co., Ltd., E220A and E220 manufactured by Nippon Silica Industry Co., Ltd., SYLYSIA 470 manufactured by Fuji Silysia Co., Ltd., and SG Flake manufactured by Nippon Sheet Glass Co., Ltd.
• colloidal silica includes, for example, methanol silica sol, IPA-ST, MEK-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, and ST-OL manufactured by Nissan Chemical Industries, Ltd.
• silica particles may also be used, for example, silica particles that have been surface-treated with a reactive silane coupling agent having a hydrophobic group, or silica particles that have been modified with a compound having a (meth)acryloyl group.
• a reactive silane coupling agent having a hydrophobic group or silica particles that have been modified with a compound having a (meth)acryloyl group.
• Commercially available powdered silica modified with a compound having a (meth)acryloyl group includes Aerosil RM50 and R711 manufactured by Nippon Aerosil Co., Ltd.
• commercially available colloidal silica modified with a compound having a (meth)acryloyl group includes MIBK-SD manufactured by Nissan Chemical Industries, Ltd.
• the shape of the silica microparticles is not particularly limited, and spherical, hollow, porous, rod-like, plate-like, fibrous, or amorphous shapes can be used.
• the primary particle size is preferably in the range of 5 to 200 nm.
• Titanium oxide fine particles can be used not only as extender pigments but also as ultraviolet light responsive photocatalysts, such as anatase type titanium oxide, rutile type titanium oxide, and brookite type titanium oxide. Furthermore, particles designed to respond to visible light by doping different elements into the crystal structure of titanium oxide can also be used. Anionic elements such as nitrogen, sulfur, carbon, fluorine, and phosphorus, and cationic elements such as chromium, iron, cobalt, and manganese are preferably used as elements to be doped into titanium oxide.
• the form that can be used can be a powder, a sol dispersed in an organic solvent or water, or a slurry.
• Examples of commercially available powdered titanium oxide fine particles include Aerosil P-25 manufactured by Nippon Aerosil Co., Ltd. and ATM-100 manufactured by Teika Co., Ltd.
• Examples of commercially available slurry-type titanium oxide fine particles include TKD-701 manufactured by Teika Co., Ltd.
• the curable resin composition of the present embodiment may further contain a fibrous substrate.
• the fibrous substrate is not particularly limited, but is preferably one used in fiber-reinforced resins, such as inorganic fibers and organic fibers.
• Inorganic fibers include inorganic fibers such as carbon fiber, glass fiber, boron fiber, alumina fiber, and silicon carbide fiber, as well as carbon fiber, activated carbon fiber, graphite fiber, tungsten carbide fiber, silicon carbide fiber (silicon carbide fiber), ceramic fiber, natural fiber, mineral fibers such as basalt, boron nitride fiber, boron carbide fiber, and metal fibers.
• the metal fibers include aluminum fiber, copper fiber, brass fiber, stainless steel fiber, and steel fiber.
• organic fibers examples include synthetic fibers made from resin materials such as polybenzazole, aramid, PBO (polyparaphenylene benzoxazole), polyphenylene sulfide, polyester, acrylic, polyamide, polyolefin, polyvinyl alcohol, and polyarylate; natural fibers such as cellulose, pulp, cotton, wool, and silk; and regenerated fibers such as proteins, polypeptides, and alginic acid.
• resin materials such as polybenzazole, aramid, PBO (polyparaphenylene benzoxazole), polyphenylene sulfide, polyester, acrylic, polyamide, polyolefin, polyvinyl alcohol, and polyarylate
• natural fibers such as cellulose, pulp, cotton, wool, and silk
• regenerated fibers such as proteins, polypeptides, and alginic acid.
• carbon fiber and glass fiber are preferred because they have a wide range of industrial applications. Of these, only one type may be used, or multiple types may be used simultaneously.
• the fibrous substrate may be an assembly of fibers, with continuous or discontinuous fibers, and in the form of a woven or nonwoven fabric. It may also be a fiber bundle in which the fibers are aligned in one direction, or in the form of a sheet in which fiber bundles are arranged. It may also be a three-dimensional shape in which the fiber assembly has thickness.
• the curable resin composition of the present embodiment may contain a dispersion medium for the purpose of adjusting the solid content and viscosity of the resin composition.
• the dispersion medium may be any liquid medium that does not impair the effects of the present embodiment, and examples of the dispersion medium include various organic solvents and liquid organic polymers.
• the organic solvents include, for example, ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); cyclic ethers such as tetrahydrofuran (THF) and dioxolane; esters such as methyl acetate, ethyl acetate, and butyl acetate; aromatics such as toluene and xylene; and alcohols such as carbitol, cellosolve, methanol, isopropanol, butanol, and propylene glycol monomethyl ether. These can be used alone or in combination. Among these, methyl ethyl ketone is preferred from the standpoint of volatility during coating and solvent recovery.
• ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK)
• cyclic ethers such as tetrahydrofuran (TH
• the liquid organic polymer is a liquid organic polymer that does not directly contribute to the curing reaction, and examples include acrylic polymer (Floren WK-20: Kyoeisha), amine salt of special modified phosphate ester (HIPLAAD ED-251: Kusumoto Chemical), modified acrylic block copolymer (DISPERBYK2000; BYK-Chemie), etc.
• the curable resin composition of the present embodiment may contain other compounds, such as a catalyst, a polymerization initiator, an inorganic pigment, an organic pigment, an extender pigment, a clay mineral, a wax, a surfactant, a stabilizer, a flow control agent, a coupling agent, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a flame retardant, a plasticizer, and a reactive diluent.
• a catalyst such as a catalyst, a polymerization initiator, an inorganic pigment, an organic pigment, an extender pigment, a clay mineral, a wax, a surfactant, a stabilizer, a flow control agent, a coupling agent, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a flame retardant, a plasticizer, and a reactive diluent.
• the curable resin composition of this embodiment can be cured to obtain a cured product.
• Curing can be performed at room temperature or by heating.
• curing can be performed by a single heating step or by going through a multi-stage heating process.
• the curable resin composition of this embodiment can also be cured with active energy rays.
• a photocationic polymerization initiator can be used as the polymerization initiator.
• active energy rays include visible light, ultraviolet light, X-rays, and electron beams.
• photocationic polymerization initiators include aryl-sulfonium salts and aryl-iodonium salts. Specifically, arylsulfonium hexafluorophosphate, arylsulfonium hexafluoroantimonate, arylsulfonium tetrakis(pentafluoro)borate, tri(alkylphenyl)sulfonium hexafluorophosphate, etc. can be used.
• the photocationic polymerization initiators may be used alone or in combination of two or more kinds.
• the curable resin composition of the present embodiment may be prepared by uniformly mixing the above-mentioned components, and the method for doing so is not particularly limited.
• the composition may be prepared by uniformly mixing the components using a pot mill, a ball mill, a bead mill, a roll mill, a homogenizer, a super mill, a homodisper, a universal mixer, a Banbury mixer, a kneader, or the like.
• the curable resin composition of this embodiment is prepared by dissolving the epoxy resin (A) of this embodiment, the epoxy resin (B) of this embodiment, the curable functional group-containing compound (C) of this embodiment, and the thermally expandable particles (D) of this embodiment, and further, if necessary, the curing agent, filler, fibrous substrate, dispersion medium, and resin other than the various compounds that can be used in combination with the curable resin composition, in a dispersion medium such as the organic solvent. After dissolution, the solvent is distilled off and the curable resin composition can be obtained by drying under reduced pressure using a vacuum oven or the like.
• the curable resin composition of this embodiment may be in a state in which the above-mentioned constituent materials are uniformly mixed.
• the materials uniformly using a mixer or the like.
• the mixing ratio of each constituent material can be appropriately adjusted according to the desired characteristics of the cured product, such as mechanical strength and heat resistance.
• the order in which the constituent materials are mixed is not particularly limited in the preparation of the curable resin composition.
• the cured product of the present embodiment is obtained by curing the curable resin composition of the present embodiment.
• the curing method can be appropriately selected and adopted from known methods depending on the properties of the epoxy resin (A), the epoxy resin (B), and the curable functional group-containing compound (C) used.
• the cured product of this embodiment is cured by the curable functional group-containing compound (C) of this embodiment as described above, and therefore can maintain good mechanical strength by exhibiting an appropriate crosslink density.
• IR infrared absorption
• FT-IR Fourier transform infrared spectroscopy
• the cured product produced from the curable resin composition of this embodiment has adhesive properties, flexibility, and dismantling properties, and is useful for the following applications:
• the cured product of the curable resin of this embodiment can be laminated with a substrate to form a laminate.
• the substrate of the laminate can be an inorganic material such as metal or glass, or an organic material such as plastic or wood, and can be used as appropriate depending on the application.
• the substrate can be in the shape of a laminate, a flat plate, a sheet, or a three-dimensional structure, or it can be three-dimensional. It can be any shape depending on the purpose, such as one with curvature over the entire surface or part. There is no restriction on the hardness or thickness of the substrate.
• a multilayer laminate can be formed by laminating a first substrate, a layer made of the cured product of the curable resin composition of this embodiment, and a second substrate in this order.
• the curable resin composition of this embodiment has excellent adhesive properties, so it can be suitably used as an adhesive for bonding a first substrate and a second substrate.
• the cured product of the curable resin of this embodiment can be used as a substrate, and the cured product of this embodiment can be further laminated.
• the cured product of the curable resin of this embodiment is capable of relieving stress, and is therefore particularly suitable for use in bonding dissimilar materials.
• the substrate is a metal and/or metal oxide and the second substrate is a laminate of dissimilar materials such as a plastic layer, the adhesive strength is maintained due to the stress relieving ability of the cured product of this embodiment.
• the layer containing the cured product may be formed by direct coating or molding on the substrate, or an already molded product may be laminated.
• the coating method is not particularly limited, and examples thereof include spraying, spin coating, dip coating, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, and inkjet coating.
• directly molding examples include in-mold molding, insert molding, vacuum molding, extrusion lamination molding, and press molding.
• the cured product of this embodiment may be laminated by coating a precursor that can be a substrate and curing it, or the precursor that can be a substrate or the composition of this embodiment may be adhered in an uncured or semi-cured state and then cured.
• a precursor that can be a substrate and examples thereof include various curable resin compositions.
• the cured product obtained using the curable resin composition of this embodiment has particularly high adhesion to metals and/or metal oxides, and can be particularly well used as a primer for metals.
• Metals include copper, aluminum, gold, silver, iron, platinum, chromium, nickel, tin, titanium, zinc, various alloys, and composite materials of these, while metal oxides include single oxides and/or composite oxides of these metals. Since the composition has particularly excellent adhesion to iron, copper, and aluminum, it can be particularly well used as an adhesive for iron, copper, and aluminum.
• the curable resin composition of this embodiment can be suitably used as an adhesive for structural members in the fields of automobiles, trains, civil engineering and construction, electronics, aircraft, and the space industry. Even when used to bond dissimilar materials such as metal and nonmetal, the adhesive can maintain high adhesion without being affected by changes in the temperature environment, and peeling and the like is unlikely to occur.
• the adhesive can also be used as an adhesive for general office use, medical use, carbon fiber, storage battery cells, modules, and cases, and can be used as an adhesive for bonding optical components, bonding optical disks, mounting printed wiring boards, die bonding adhesives, semiconductor adhesives such as underfills, underfills for reinforcing BGAs, anisotropic conductive films, anisotropic conductive pastes, and other mounting adhesives.
• the curable resin composition of this embodiment has a fibrous substrate, and the fibrous substrate is a reinforcing fiber
• the curable resin composition containing the fibrous substrate can be used as a fiber-reinforced resin.
• the method of incorporating the fibrous substrate into the composition is not particularly limited as long as it does not impair the effects of this embodiment, and examples of the method include a method of combining the fibrous substrate and the composition by kneading, coating, impregnation, injection, compression bonding, etc., and can be selected appropriately depending on the form of the fiber and the application of the fiber-reinforced resin.
• extrusion molding is common. Plane pressing is also possible. Other methods that can be used include extrusion molding, blow molding, compression molding, vacuum molding, and injection molding. If a film-shaped product is to be manufactured, in addition to melt extrusion, solution casting can be used. Examples of melt molding methods include inflation film molding, cast molding, extrusion lamination molding, calendar molding, sheet molding, fiber molding, blow molding, injection molding, rotational molding, and coating molding. In the case of resins that are cured with active energy rays, cured products can be manufactured using various curing methods that use active energy rays.
• the matrix resin is mainly composed of a thermosetting resin
• a molding method in which the molding material is made into a prepreg and pressurized and heated using a press or autoclave is exemplified.
• Other examples include RTM (Resin Transfer Molding) molding, VaRTM (Vacuum Assist Resin Transfer Molding) molding, laminate molding, hand layup molding, etc.
• the curable resin composition of this embodiment has excellent adhesion, flexibility and ease of dismantling, and can be used for molding materials such as large cases, motor housings, casting materials for the inside of cases, and gears and pulleys. These may be cured products of resin alone, or cured products reinforced with fibers such as glass chips.
• Fiber reinforced resin can form an uncured or semi-cured state known as prepreg. After distributing the product in prepreg state, it may be subjected to final curing to form a cured product. When forming a laminate, it is preferable to form the prepreg, then laminate other layers and then perform final curing, since this allows the formation of a laminate in which each layer is in close contact. There are no particular limitations on the mass ratio of the composition and fibrous substrate used in this case, but it is usually preferable to prepare the resin content in the prepreg to be 20 to 60 mass%.
• the cured product of this embodiment has excellent adhesion, flexibility, and dismantling properties, and can be used as a heat-resistant material and electronic material.
• it can be suitably used as a semiconductor encapsulant, circuit board, build-up film, build-up board, adhesive, and resist material.
• It can also be suitably used as a matrix resin for fiber-reinforced resin, and is particularly suitable as a highly heat-resistant prepreg.
• the heat-resistant and electronic components thus obtained can be suitably used for a variety of applications, including, but not limited to, industrial machine parts, general machine parts, automobile, railway, and vehicle parts, space and aviation-related parts, electronic and electrical parts, building materials, containers and packaging parts, daily necessities, sports and leisure goods, and housing parts for wind power generation.
• the adhesive of this embodiment can maintain high adhesion without being affected by changes in the temperature environment, even when used to bond dissimilar materials such as metal and non-metal, and is unlikely to peel off.
• the adhesive of this embodiment can also be used as an adhesive for general office use, medical use, carbon fiber, storage battery cells, modules, and cases, etc.
• examples of the adhesive include an adhesive for bonding optical components, an adhesive for bonding optical disks, an adhesive for mounting printed wiring boards, a die bonding adhesive, an adhesive for semiconductors such as underfill, an underfill for reinforcing BGA, an anisotropic conductive film, an anisotropic conductive paste, and other mounting adhesives.
• an easily dismantled adhesive material containing the curable resin composition of this embodiment can be used.
• the easily dismantled adhesive material is preferably the curable resin composition of this embodiment.
• the dismantling method using the easily dismantled adhesive material includes, for example, a bonding step of attaching the easily dismantled adhesive material to the surface of an adherend and bonding it to the adherend, a curing step of curing the easily dismantled adhesive material to obtain a cured product, a heat treatment step of thermally dissociating the reversible bond contained in any one of the general formulas (4-1) and (4-2) derived from the curable functional group-containing compound (C) and expanding the thermally expandable particles (D) on the cured product, and a dismantling step of dismantling the adherend and the cured product.
• the dismantling method using the easily dismantlable adhesive material of this embodiment may include, for example, a bonding step of attaching the easily dismantlable adhesive material to the surface of an adherend and bonding it to the adherend, a curing step of curing the easily dismantlable adhesive material to obtain a cured product, a heat treatment step of performing a heat treatment on the cured product to thermally dissociate a reversible bond contained in any one of the general formulas (4-1) and (4-2) derived from the curable functional group-containing compound (C) and expand the heat-expandable particles (D), a cooling step of cooling the cured product after the heat treatment to room temperature, and a dismantling step of dismantling the adherend and the cured product.
• a bonding step of attaching the easily dismantlable adhesive material to the surface of an adherend and bonding it to the adherend may include, for example, a bonding step of attaching the easily dismantlable adhesive material to the
• the resin composition, the curing accelerator, and compounding agents such as inorganic fillers are melt-mixed sufficiently until homogeneous using an extruder, kneader, roll, or the like as necessary.
• fused silica is usually used as the inorganic filler, but when used as a high thermal conductivity semiconductor encapsulation material for power transistors and power ICs, it is preferable to use highly filled crystalline silica, alumina, silicon nitride, etc., which have a higher thermal conductivity than fused silica, or fused silica, crystalline silica, alumina, silicon nitride, etc.
• the filling rate is preferably in the range of 30 to 95 mass% per 100 parts by mass of the curable resin composition, and among them, in order to improve flame retardancy, moisture resistance, and solder crack resistance and to reduce the linear expansion coefficient, it is more preferable that the inorganic filler is 70 parts by mass or more, and even more preferable that the inorganic filler is 80 parts by mass or more.
• a semiconductor package molding method for obtaining a semiconductor device from the curable resin composition of the present embodiment includes a method in which the semiconductor encapsulating material is molded by casting or using a transfer molding machine, an injection molding machine, or the like, and then heated at 50 to 250°C for 2 to 10 hours.
• a method for obtaining a printed circuit board from the composition of the present embodiment includes laminating the prepreg by a conventional method, appropriately overlaying copper foil, and subjecting the laminate to heat-pressure bonding at 170 to 300°C under a pressure of 1 to 10 MPa for 10 minutes to 3 hours.
• a method for producing a flexible substrate from the crosslinkable resin composition of this embodiment includes a method comprising the following three steps.
• the first step is a step of applying a crosslinkable resin composition containing a resin component, an organic solvent, and the like to an electrical insulating film using a coater such as a reverse roll coater or a comma coater.
• the second step is a step of heating the electrical insulating film to which the crosslinkable resin composition has been applied at 60 to 170° C. for 1 to 15 minutes using a heater to volatilize the solvent from the electrical insulating film and to B-stage the crosslinkable resin composition.
• the third step is a step of thermocompression bonding (preferably a compression pressure of 2 to 200 N/cm and a compression temperature of 40 to 200° C.) a metal foil to an adhesive on the electrical insulating film to which the crosslinkable resin composition has been B-staged using a heating roll or the like. If sufficient adhesive performance is obtained by going through the above three steps, the process may be terminated here, but if complete adhesive performance is required, it is preferable to further post-cure the resin composition at 100 to 200° C. for 1 to 24 hours.
• the thickness of the resin composition layer after final curing is preferably in the range of 5 to 100 ⁇ m.
• the method for obtaining a build-up substrate from the composition of this embodiment includes, for example, the following steps. First, the composition containing an appropriate blend of rubber, filler, etc. is applied to a circuit board on which a circuit is formed by using a spray coating method, a curtain coating method, etc., and then cured (step 1). Thereafter, a predetermined through-hole portion or the like is drilled as necessary, the surface is treated with a roughening agent, and the surface is washed with hot water to form unevenness, and a metal such as copper is plated (step 2). These operations are repeated as desired to alternately build up resin insulating layers and conductor layers of a predetermined circuit pattern (step 3).
• the build-up substrate of this embodiment can also be produced by forming a roughened surface by heating and pressing the resin-coated copper foil, which is a copper foil on which the resin composition is semi-cured, onto a wiring board on which a circuit is formed, at 170 to 300° C., thereby forming a build-up substrate without the steps of plating.
• a build-up film can be obtained from the composition of the present embodiment by applying the composition to the surface of a support film (Y) that is a substrate, and then drying the organic solvent by heating or blowing hot air thereon to form a layer of the composition (X).
• the organic solvents used here preferably include, for example, ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and it is preferable to use them in a proportion that results in a non-volatile content of 30 to 60% by mass.
• ketones such as acetone, methyl ethyl ketone, and cyclohexanone
• acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether
• the thickness of the layer (X) formed is usually equal to or greater than the thickness of the conductor layer. Since the thickness of the conductor layer of a circuit board is usually in the range of 5 to 70 ⁇ m, it is preferable that the resin composition layer has a thickness of 10 to 100 ⁇ m.
• the composition layer (X) may be protected with a protective film, which will be described later. By protecting the resin composition layer with a protective film, it is possible to prevent the adhesion of dirt and the like to the surface of the resin composition layer and prevent scratches.
• the above-mentioned support film and protective film may be made of polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate; polycarbonate; polyimide; and even release paper and metal foils such as copper foil and aluminum foil.
• the support film and protective film may be subjected to a matte treatment, corona treatment, or release treatment.
• There are no particular limitations on the thickness of the support film but it is usually 10 to 150 ⁇ m, and preferably 25 to 50 ⁇ m.
• the thickness of the protective film is preferably 1 to 40 ⁇ m.
• the support film (Y) is peeled off after laminating it onto the circuit board or after forming an insulating layer by heat curing. If the support film (Y) is peeled off after the curable resin composition layer constituting the build-up film has been heat cured, the adhesion of dirt and the like during the curing process can be prevented. When peeling off after curing, the support film is usually subjected to a release treatment in advance.
• a multilayer printed circuit board can be manufactured using the build-up film obtained as described above.
• the protective film is peeled off, and then the layer (X) is laminated on one or both sides of the circuit board so as to be in direct contact with the circuit board, for example, by a vacuum lamination method.
• the lamination method may be a batch type or a continuous type using a roll. If necessary, the build-up film and the circuit board may be heated (preheated) before lamination.
• the lamination conditions are preferably a pressure bonding temperature (lamination temperature) of 70 to 140°C, a pressure bonding pressure of 1 to 11 kgf/cm 2 (9.8 ⁇ 10 4 to 107.9 ⁇ 10 4 N/m 2 ), and lamination is preferably performed under reduced pressure of 20 mmHg (26.7 hPa) or less.
• Conductive Paste As a method for obtaining a conductive paste from the curable resin composition of the present embodiment, for example, a method of dispersing conductive particles in the composition can be mentioned.
• the conductive paste can be a paste resin composition for circuit connection or an anisotropic conductive adhesive depending on the type of conductive particles used.
• GPC Tosoh Corporation "HLC-8320GPC" Column: “TSK-GEL G2000HXL” + “TSK-GEL G3000HXL” + “TSK-GEL G4000HXL” manufactured by Tosoh Corporation Detector: RI (differential refractometer) Measurement condition: 40°C Mobile phase: Tetrahydrofuran Flow rate: 1 ml/min Standard: Tosoh Corporation's "PStQuick A", “PStQuick B", "PStQuick E", and "PStQuick F"
• the epoxy equivalent of the synthesized epoxy resin was measured according to JIS K7236, and the epoxy equivalent (g/eq) was calculated.
• Examples of methods for calculating the number of repeating units include calculations based on the results of various appropriate instrumental analyses such as GPC molecular weight measurement, FD-MS, and NMR.
• Synthesis Example 1 A flask equipped with a thermometer, a condenser, and a stirrer was charged with 420 g (2.0 equivalents) of diglycidyl ether of 1,12-dodecanediol (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g/eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g/eq), and the temperature was raised to 140°C over 30 minutes, after which 6.6 g of a 20% aqueous sodium hydroxide solution was charged. The temperature was then raised to 150°C over 30 minutes, and the mixture was further reacted at 150°C for 16 hours.
• Synthesis Example 2 The reaction was carried out in the same manner as in Synthesis Example 1, except that 420 g (2.0 equivalents) of the diglycidyl ether of 1,12-dodecanediol (epoxy equivalent 210 g/eq) in Synthesis Example 1 was changed to 472 g (2.0 equivalents) of the diglycidyl ether of 1,15-pentadecanediol (epoxy equivalent 236 g/eq), and 697 g of hydroxy compound (Ph-2) was obtained.
• the hydroxyl group equivalent of this hydroxy compound (Ph-2) calculated by GPC was 2226 g/eq, and the average value of the repeating unit m was 6.8.
• Synthesis Example 3 The reaction was carried out in the same manner as in Synthesis Example 1, except that 420 g (2.0 equivalents) of the diglycidyl ether of 1,12-dodecanediol (epoxy equivalent 210 g/eq) in Synthesis Example 1 was changed to 380 g (2.0 equivalents) of the diglycidyl ether of 1,9-nonanediol (epoxy equivalent 190 g/eq), and 607 g of hydroxy compound (Ph-3) was obtained.
• the hydroxyl group equivalent of this hydroxy compound (Ph-3) calculated by GPC was 1989 g/eq, and the average value of the repeating unit m was 7.2.
• Synthesis Example 4 The same reaction as in Synthesis Example 1 was carried out except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g/eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g/eq) in Synthesis Example 1 were changed to 962 g (2.0 equivalents) of polypropylene glycol diglycidyl ether (manufactured by Nagase ChemteX Co., Ltd.
• Synthesis Example 5 The reaction was carried out in the same manner as in Synthesis Example 1, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g/eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g/eq) in Synthesis Example 1 were changed to 890 g (2.0 equivalents) of polytetramethylene glycol diglycidyl ether (manufactured by Nagase ChemteX Co., Ltd.
• Synthesis Example 6 The reaction was carried out in the same manner as in Synthesis Example 1, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Chemical Co., Ltd.: epoxy equivalent 210 g/eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g/eq) in Synthesis Example 1 were changed to 126.2 g (0.39 mol) of 1,6-hexanediol diglycidyl ether (manufactured by Sakamoto Yakuhin Co., Ltd.: epoxy equivalent 160 g/eq), 78.1 g (0.08 mol) of polypropylene glycol diglycidyl ether (manufactured by Nagase ChemteX Co., Ltd.: epoxy equivalent 481 g/eq), and 114.6 g (0.50 mol) of bisphenol A (hydroxyl equivalent 114 g/eq), and
• the hydroxyl equivalent of this hydroxy compound (Ph-6) calculated by GPC was 1597 g/eq.
• Synthesis Example 7 The reaction was carried out in the same manner as in Synthesis Example 1, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Chemical Co., Ltd.: epoxy equivalent 210 g/eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g/eq) in Synthesis Example 1 were changed to 136 g (0.43 mol) of 1,6-hexanediol diglycidyl ether (manufactured by Sakamoto Yakuhin Co., Ltd.
• the hydroxyl equivalent of this hydroxy compound (Ph-7) calculated by GPC was 1896 g/eq.
• Synthesis Example 8 A flask equipped with a thermometer, a condenser, and a stirrer was charged with 420 g (2.0 equivalents) of diglycidyl ether of 1,12-dodecanediol (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g/eq) and 456 g (4.0 equivalents) of bisphenol A (hydroxyl equivalent 114 g/eq), and the temperature was raised to 140°C over 30 minutes, after which 4.0 g of 4% aqueous sodium hydroxide solution was charged. The temperature was then raised to 150°C over 30 minutes, and the mixture was further reacted at 150°C for 6 hours.
• Synthesis Example 9 The reaction was carried out in the same manner as in Synthesis Example 8, except that 420 g (2.0 equivalents) of the diglycidyl ether of 1,12-dodecanediol (epoxy equivalent 210 g/eq) in Synthesis Example 8 was replaced with 962 g (2.0 equivalents) of the diglycidyl ether of polypropylene glycol ("Denacol EX-931" manufactured by Nagase ChemteX: epoxy equivalent 481 g/eq), to obtain 1390 g of hydroxy compound (Ph-9).
• Synthesis Example 10 In a flask equipped with a thermometer, a dropping funnel, a cooling tube and a stirrer, 205.3 g of the hydroxy compound (Ph-1) obtained in Synthesis Example 1, 647.5 g (7.0 mol) of epichlorohydrin, and 150 g of n-butanol were added and dissolved while purging with nitrogen gas. After that, the temperature was raised to 65°C, and the pressure was reduced to the pressure at which azeotropy occurred, and 10.6 g (0.13 mol) of a 49% aqueous sodium hydroxide solution was dropped over 5 hours. Next, stirring was continued for 0.5 hours under the same conditions.
• Synthesis Example 11 The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 222.6 g of the hydroxy compound (Ph-2), to obtain 251 g of epoxy resin (Ep-2).
• the epoxy equivalent of the obtained epoxy resin (Ep-2) was 2510 g/eq.
• Synthesis Example 12 The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 198.9 g of the hydroxy compound (Ph-3), to obtain 229 g of epoxy resin (Ep-3).
• the epoxy equivalent of the obtained epoxy resin (Ep-3) was 2250 g/eq.
• Synthesis Example 13 The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 158.2 g of the hydroxy compound (Ph-4), and 193 g of epoxy resin (Ep-4) was obtained.
• the epoxy equivalent of the obtained epoxy resin (Ep-4) was 1802 g/eq.
• Synthesis Example 14 The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was replaced with 252.0 g of the hydroxy compound (Ph-5), to obtain 277 g of epoxy resin (Ep-5).
• the epoxy equivalent of the obtained epoxy resin (Ep-5) was 2834 g/eq.
• Synthesis Example 15 The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was replaced with 198.4 g of the hydroxy compound (Ph-6), to obtain 229 g of epoxy resin (Ep-6).
• the epoxy equivalent of the obtained epoxy resin (Ep-6) was 2244 g/eq.
• Synthesis Example 16 The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was replaced with 191.4 g of the hydroxy compound (Ph-7), to obtain 223 g of epoxy resin (Ep-7).
• the epoxy equivalent of the obtained epoxy resin (Ep-7) was 2167 g/eq.
• Synthesis Example 17 The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 388 g of the hydroxy compound (Ph-8), to obtain 399 g of epoxy resin (Ep-8).
• the epoxy equivalent of the obtained epoxy resin (Ep-8) was 488 g/eq.
• Synthesis Example 18 The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 593 g of the hydroxy compound (Ph-9), and 584 g of an epoxy resin (Ep-9) was obtained.
• the epoxy equivalent of the obtained epoxy resin (Ep-9) was 714 g/eq.
• the molecular weight per mole of the furan structure of this furan compound (F-1) calculated from 1H-NMR was 575 g/eq.
• Synthesis Example 20 In a flask equipped with a thermometer, a stirrer, and a condenser, 29 g of the furan compound (F-1, furan equivalent: 575 g/eq) obtained in Synthesis Example 19, 5.3 g of 1,6'-bismaleimide-(2,2,4-trimethyl)hexane (BMI-THM, manufactured by Daiwa Kasei Kogyo Co., Ltd.), and 50 g of toluene were charged, and after nitrogen replacement, the mixture was reacted at 60°C for 20 hours. Thereafter, the toluene was distilled off under reduced pressure to obtain 34 g of a furan compound (F-2).
• BMI-THM 1,6'-bismaleimide-(2,2,4-trimethyl)hexane
• the molecular weight per mole of the furan structure calculated from 1 H-NMR was 2043 g/eq.
• * indicates that the compound is directly bonded to the position of * in the next line.
• Synthesis Example 21 The same reaction as in Synthesis Example 19 was carried out, except that 48.8 g (epoxy equivalent: 488 g/eq) of epoxy resin (Ep-8) in Synthesis Example 19 was changed to 71.4 g (epoxy equivalent: 714 g/eq) of epoxy resin (Ep-9), to obtain 73 g of furan compound (F-3).
• the molecular weight per mole of the furan structure of this furan compound (F-3) calculated from 1 H-NMR was 796 g/eq.
• Synthesis Example 22 The same reaction as in Synthesis Example 20 was carried out, except that 29 g of the furan compound (F-1, furan equivalent 575 g/eq) in Synthesis Example 20 was changed to 40 g of the furan compound (F-3, furan equivalent 796 g/eq), to obtain 46 g of a furan compound (F-4).
• the molecular weight per mole of the furan structure calculated by 1 H-NMR was 2706 g/eq.
• Synthesis Example 23 The same reaction as in Synthesis Example 20 was carried out, except that the amount of 1,6'-bismaleimide-(2,2,4-trimethyl)hexane (BMI-THM manufactured by Daiwa Kasei Kogyo Co., Ltd.) was changed from 5.3 g to 11.9 g, to obtain 41 g of maleimide compound (M-1).
• the molecular weight per mole of maleimide structure calculated by 1H-NMR was 1627 g/eq.
• Synthesis Example 25 The reaction was carried out in the same manner as in Synthesis Example 24, except that 34 g of the furan compound (F-2, furan equivalent 2043 g/eq) in Synthesis Example 24 was changed to 45 g of a furan compound (F-4, furan equivalent 2706 g/eq), to obtain 44 g of an amino group-containing compound (D-2).
• the active hydrogen equivalent calculated by 1H-NMR was 1447 g/eq.
• M-1 maleimide equivalent 1627 g/eq
• Synthesis Example 29 The same reaction as in Synthesis Example 28 was carried out, except that 34 g of the furan compound (F-2, furan equivalent 2043 g/eq) in Synthesis Example 28 was changed to 45 g of the furan compound (F-4, furan equivalent 2706 g/eq), to obtain 44 g of a phenolic hydroxyl group-containing compound (D-6).
• the hydroxyl group equivalent calculated by 1H-NMR was 2895 g/eq.
• ⁇ Structural periodicity> A cross section of the cured resin was prepared using an ultramicrotome, and the structural periodicity was observed using a scanning electron microscope (SEM) so that the contrast of the morphology could be clearly distinguished.
• compositions shown in the table are as follows: E-850S: Bisphenol A type liquid epoxy resin (manufactured by DIC Corporation, epoxy equivalent 188 g/eq) DICY: Dicyandiamide ("DICY7" manufactured by Mitsubishi Chemical Corporation) DCMU: 3-(3,4-dichlorophenyl)-1,1-dimethylurea (manufactured by DIC Corporation, "B-605-IM") DTA: Diethylenetriamine (Kanto Chemical) F-260D, F-190D: Thermal expansion capsule (Matsumoto Yushi Seiyaku) 953240L: Thermally expandable graphite (Ito Graphite Industry) EXP 50S150: Thermally expandable graphite (Fuji Graphite Industry)
• this system has a phase separation structure, suggesting the possibility that the reversible bonding units are unevenly distributed in the adhesive layer.
• the uneven distribution of the reversible bonding structures in the flexible sea phase enhances the dissociation effect caused by the Retro-Diels-Alder reaction when heated. As a result, it is speculated that this induces softening and embrittlement of the adhesive layer when heated, further promoting the expansion effect of the expansion capsules, resulting in improved reproducibility of easy disassembly.
• Comparative examples 1 and 4 did not exhibit dismantling capabilities because they did not contain an expansion material in their compositions. When heated, reversible bonds dissociate (Retro Diels-Alder reaction), but the bonds are re-formed (Diels-Alder reaction) during the cooling process to room temperature, which is thought to be why dismantling capabilities did not appear under room temperature conditions.
• Comparative Examples 2 and 5 there was a large variation in adhesive strength when the adherend was further heated, and the dismantling function could not be reproduced. Comparative Examples 2 and 5 did not contain reversible bonds, and it is presumed that the function was not fully realized by the effect of the expanding agent alone.
• Comparative examples 3 and 6 showed very low flexibility and initial adhesive strength of the cured product.
• the phase separation structure of epoxy resin (A) and epoxy resin (B) provided both flexibility and adhesiveness, but in comparative examples 3 and 6, the phase separation structure did not appear, and it is believed that flexibility and adhesiveness were not achieved.

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