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EP-4130090-B1 - CURABLE RESIN COMPOSITION AND METHOD FOR SUPPRESSING CURING SHRINKAGE OF CURABLE RESIN COMPOSITION

EP4130090B1EP 4130090 B1EP4130090 B1EP 4130090B1EP-4130090-B1

Inventors

  • ENDO, TAKESHI
  • UEYAMA, JUNJI
  • OGAWA, RYO

Dates

Publication Date
20260506
Application Date
20210316

Claims (14)

  1. A curable resin composition comprising: (A) an epoxy resin, (B) a latent curing agent, and (C) a compound selected from U-4, U-6, U-10, U-12, U-13, and U-14 shown below:
  2. The curable resin composition according to claim 1, further comprising (D) a cyanate ester resin.
  3. The curable resin composition according to claim 2, wherein the cyanate ester resin (D) comprises at least one member selected from the group consisting of a compound represented by formula (2): [Chem. 2] NC-O-A 1 -Y 1 -A 2 -O-CN (2) wherein Y 1 represents an unsubstituted or fluorine-substituted divalent hydrocarbon group, -O-, -S-, or a single bond; and A 1 and A 2 each independently represent an unsubstituted phenylene group or a phenylene group substituted with an alkyl group having 1 to 4 carbon atoms; a compound represented by formula (3): wherein m represents an integer of 1 or greater; Y 2 and Y 3 each independently represent an unsubstituted or fluorine-substituted divalent hydrocarbon group; and R 5 , R 6 , R 7 , R 8 , R 9 , and R 10 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and a polymer thereof.
  4. The curable resin composition according to claim 3, wherein Y 1 in formula (2) and Y 2 and Y 3 in formula (3) each comprises at least one structure represented by any one of the following formulae (Y-1) through (Y-9): wherein n represents an integer of 4 to 12; R 11 and R 12 each independently represent a hydrogen atom or an unsubstituted or fluorine-substituted methyl group; and an asterisk indicates a bond.
  5. The curable resin composition according to any one of claims 1 to 4, wherein the latent curing agent (B) is an active hydrogen-containing amine-based latent curing agent.
  6. The curable resin composition according to claim 5, wherein the active hydrogen-containing amine-based latent curing agent comprises at least one guanidine compound.
  7. The curable resin composition according to claim 5, wherein the active hydrogen-containing amine-based latent curing agent comprises at least one member selected from (B-1) a modified amine obtained by the reaction between an amine compound having one or more active hydrogens and an epoxy compound, (B-2) a modified amine obtained by the reaction between an amine compound having one or more active hydrogens and an isocyanate compound, (B-3) a modified amine obtained by the reaction between an amine compound having one or more active hydrogens, an epoxy compound, and an isocyanate compound, and (B-4) a composition comprising at least one modified amine selected from (B-1), (B-2), and (B-3) and a phenol resin.
  8. The curable resin composition according to any one of claims 2 to 7, wherein the cyanate ester resin (D) is present in an amount of 10 to 1000 parts by mass per 100 parts by mass of the epoxy resin (A).
  9. The curable resin composition according to any one of claims 1 to 8, wherein the latent curing agent (B) is present in an amount of 1 to 100 parts by mass per 100 parts by mass of the epoxy resin (A).
  10. The curable resin composition according to any one of claims 1 to 9, wherein the compound (C) selected from U-4, U-6, U-10, U-12, U-13, and U-14 is present in an amount of 0.5 to 20 parts by mass per 100 parts by mass of the total amount of the epoxy resin (A) and the latent curing agent (B).
  11. A cured product obtained from the curable resin composition according to any one of claims 1 to 10.
  12. A method for reducing or controlling shrinkage of a cured product obtained from a curable resin composition comprising (A) an epoxy resin and (B) a latent curing agent, the method comprising curing the resin composition in the presence of (C) a compound represented by formula (1): wherein X represents an oxygen atom or a sulfur atom; R 1 and R 2 each independently represent a hydrogen atom, an alkyl group, or an aryl group; and R 3 and R 4 each independently represent a hydrogen atom, an alkyl group, or an aryl group, or R 3 and R 4 are connected to each other to represent a divalent group to form a ring.
  13. The method according to claim 12, wherein the compound (C) represented by formula (1) comprises at least one compound selected from U-1, U-4, U-5, U-6, U-10, U-12, and U-13 shown below:
  14. The method according to claim 12 or 13, wherein the curable resin composition further comprises (D) a cyanate ester resin.

Description

Technical Field This invention relates to a curable resin composition, more particularly a curable resin composition containing an epoxy resin, a latent curing agent, and a specific urea compound and exhibiting reduced or controlled shrinkage on curing. Background Art Epoxy resins are widely used in industry in the fields such as coatings, adhesives, and various molding materials. Use of existing epoxy resins, either alone or in combination, may be unsatisfactory in some cases, and a cyanate-epoxy composite resin composition composed of an epoxy resin and a cyanate ester resin has become frequently used as a useful material in such cases because of its high heat resistance. For example, resin compositions containing a cyanate ester resin, an epoxy resin, and a latent curing agent have been proposed in patent literatures 1 to 5 listed below. However, curable resin compositions containing an epoxy resin and the like shrink on curing, and this shrinkage can cause problems including cracking or warpage after cure. Various studies have been directed to the reduction of shrinkage on curing. For example, patent literatures 6 to 8 propose using a silica filler, but the effect of the addition of the silica filler is still short of satisfaction. Citation List Patent Literature Patent literature 1: JP 2001-302767APatent literature 2: JP S60-250026APatent literature 3: WO 99/05196Patent literature 4: US 9601401Patent literature 5: US 9382459Patent literature 6: US 2019/0185711Patent literature 7: JP 2006-307141APatent literature 8: JP 2019-156991A Summary of Invention An object of the invention is to provide a curable resin composition exhibiting reduced or controlled shrinkage on curing. As a result of intensive investigations, the inventors have found that a curable resin composition containing an epoxy resin, a latent curing agent, and a specific urea or thiourea compound achieves the above object. The present invention has been completed based on this finding. The invention provides a curable resin composition containing: (A) an epoxy resin, (B) a latent curing agent, and (C) a compound a compound selected from U-4, U-6, U-10, U-12, U-13, and U-14 shown below: The invention also provides a method for reducing or controlling shrinkage of a cured product obtained from a curable resin composition containing (A) an epoxy resin and (B) a latent curing agent. The method includes curing the resin composition in the presence of a component (C) of formula (1): wherein X represents an oxygen atom or a sulfur atom; R1 and R2 each independently represent a hydrogen atom, an alkyl group, or an aryl group; and R3 and R4 each independently represent a hydrogen atom, an alkyl group, or an aryl group, or R3 and R4 are connected to each other to represent a divalent group to form a ring. The invention also provides a cured product obtained from the curable resin composition. The invention enables reduction and control of shrinkage of a curable resin composition on curing, and thus enables application of the curable resin composition to adhesives, coatings, or molded products. Description of Embodiments The curable resin composition of the invention will now be described. Examples of the epoxy resin used as component (A) include polyglycidyl ether compounds of mononuclear polyhydric phenol compounds, such as hydroquinone, resorcin, pyrocatechol, and phloroglucinol; polyglycidyl ether compounds of polynuclear polyhydric phenol compounds, such as dihydroxynaphthalene, biphenol, methylenebisphenol(bisphenol F), methylene bis(orthocresol), ethylidene bisphenol, isopropylidene bisphenol (bisphenol A), isopropylidene bis(orthocresol), tetrabromobisphenol A, 1,3-bis(4-hydroxycumylbenzene), 1,4-bis(4-hydroxycumylbenzene), 1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane, thiobisphenol, sulfobisphenol, oxybisphenol, phenol novolak, orthocresol novolak, ethylphenol novolak, butylphenol novolak, octylphenol novolak, resorcin novolak, and terpenephenol; polyglycidyl ether compounds of polyhydric alcohols, such as ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyethylene glycol, polypropylene glycol, thiodiglycol, dicyclopentadiene dimethanol, 2,2-bis(4-hydroxycyclohexyl)propane (hydrogenated bisphenol A), glycerol, trimethylolpropane, pentaerythritol, sorbitol, and bisphenol A-alkylene oxide adducts; glycidyl esters of aliphatic, aromatic, or alicyclic polybasic acids, such as maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimeric acid, pyromellitic acid, tetrahydrophthalic acid, and endomethylene tetrahydrophthalic acid; homopolymers or copolymers of glycidyl methacrylate; epoxy compounds having a glycidylamino group, such as N,N-diglycidylaniline, bis(4-(N-methyl-N-glycidylamino)phenyl)methane, diglycidyl orthotoluidine, N,N-bis