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EP-4306566-B1 - CURABLE RESIN COMPOSITION, CURED PRODUCT AND ADHESIVE

EP4306566B1EP 4306566 B1EP4306566 B1EP 4306566B1EP-4306566-B1

Inventors

  • OTA, KEISUKE
  • HIRAYAMA, Kohei
  • OGAWA, RYO
  • YAMADA, SHINSUKE

Dates

Publication Date
20260506
Application Date
20220208

Claims (9)

  1. A curable resin composition comprising: (A) a cyanate ester resin; (B) an epoxy resin essentially including a 4-amino-3-methylphenol-type epoxy resin and an aliphatic epoxy resin; and (C) a latent curing agent; wherein the amount of the 4-amino-3-methylphenol-type epoxy resin within the total amount of the epoxy resins is from 20 to 100 mass%, and the amount of the aliphatic epoxy resin within the total amount of the epoxy resins is from 1 to 70 mass%.
  2. The curable resin composition according to claim 1, wherein the cyanate ester resin, which is component (A), is at least one selected from the group consisting of a compound represented by formula (1) below, a compound represented by formula (2) below, and a polymer of the compound represented by formula (1) and/or the compound represented by formula (2): NC-O-A 1 -Y 1 -A 2 -O-CN (1) (in the formula, Y 1 represents a divalent hydrocarbon group which is not substituted or is substituted by a fluorine atom or a cyanato group, or represents -O-, -S-, or a single bond; and A 1 and A 2 each independently represent a phenylene group which is not substituted or is substituted by 1 to 4 alkyl groups); (in the formula, m represents an integer of 1 or greater; Y 2 and Y 3 each independently represent -S-, or a divalent hydrocarbon group which is not substituted or is substituted by a fluorine atom or a cyanato group; and R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms).
  3. The curable resin composition according to claim 2, wherein Y 1 in the formula (1) and Y 2 and Y 3 in the formula (2) each independently represent at least one selected from formulas (Y-1) to (Y-9) below: (in the formulas, n represents an integer from 4 to 12; R 7 and R 8 each independently represent a hydrogen atom or a methyl group which is not substituted or is substituted by a fluorine atom; and * represents a bonding site).
  4. The curable resin composition according to any one of claims 1 to 3, wherein the latent curing agent, which is component (C), is an active-hydrogen-containing amine-based latent curing agent.
  5. The curable resin composition according to claim 4, wherein the active-hydrogen-containing amine-based latent curing agent is at least one selected from (C-1) to (C-4) below: (C-1): a modified amine obtained by reacting an epoxy compound and an amine compound having one or more active hydrogens; (C-2): a modified amine obtained by reacting an isocyanate compound and an amine compound having one or more active hydrogens; (C-3): a modified amine obtained by reacting an epoxy compound, an isocyanate compound, and an amine compound having one or more active hydrogens; and (C-4): a latent curing agent containing a phenol resin in addition to at least one of modified amine selected from (C-1), (C-2), or (C-3).
  6. The curable resin composition according to any one of claims 1 to 5, wherein a content of the 4-amino-3-methylphenol-type epoxy resin is from 1 to 200 parts by mass with respect to 100 parts by mass of the cyanate ester resin, which is component (A).
  7. The curable resin composition according to any one of claims 1 to 6, wherein, when a viscosity is measured using an E-type rotational viscometer at 10 rpm at 25°C, an initial viscosity is 70 Pa·s or less, and a viscosity increase rate after being left to stand at 40°C for 72 hours is 150% or less.
  8. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 7.
  9. An adhesive comprising the curable resin composition according to any one of claims 1 to 7.

Description

Technical Field The present invention relates to a curable resin composition, and more specifically, relates to a curable resin composition containing a cyanate ester resin, a specific epoxy resin, and a latent curing agent. Background Art Epoxy resins have a wide variety of industrial uses as components or materials constituting coating materials, adhesives, various molding materials, etc. Meanwhile, properties, such as heat resistance etc., may be insufficient in cases of simply using an existing epoxy resin singly or a plurality of types of epoxy resins as a mixture. To address this, cyanate-epoxy composite resin compositions obtained by mixing an epoxy resin and a cyanate ester resin have become widely used as useful materials because of their high heat resistance. For example, a semiconductor-sealing liquid epoxy resin composition including a cyanate ester resin, an epoxy resin, an inorganic filler, a metal chelate, and a dihydrazide compound has previously been proposed (Patent Literature 1). Unfortunately, this composition has unsatisfactory properties, such as the need for heating at high temperatures for a long period of time for curing. Further, the use of an amine-based curing agent in a composite composition containing a cyanate ester resin and an epoxy resin has also been proposed (Patent Literature 2). With this technique, however, sufficient storage stability has not been obtained. Furthermore, a thermosetting resin composition including a cyanate ester resin, an epoxy resin, and a latent curing agent containing an imidazole component has also been proposed (Patent Literature 3). Unfortunately, this composition is unsatisfactory, in terms that the amount of use of the cyanate ester resin is limited from the viewpoint of obtaining sufficient storage stability. Further, a composite resin composition employing, in combination, a cyanate ester resin, an epoxy resin, a guanidine compound, and a phenol compound has also been proposed (Patent Literature 4). The heat resistance of this composition, however, is not fully satisfactory. Furthermore, a composite resin composition obtained by combining an amine-based latent curing agent with a combination of an epoxy resin and a cyanate ester resin having a large number of functional groups has also been proposed (Patent Literature 5). The storage stability of this composition, however, is not fully satisfactory. Patent Literatures 6 to 8 disclose 4-amino-3-methylphenol-type epoxy resins used in the present invention, but do not disclose the combined use thereof with a cyanate ester resin. Citation List Patent Literature Patent Literature 1: US Patent No. 6469074Patent Literature 2: JP S60-250026APatent Literature 3: US 2002/058778A1Patent Literature 4: US 2012/178853A1Patent Literature 5: US 2012/309923A1 and WO 2011/099292 A1Patent Literature 6: US 2009/311827A1Patent Literature 7: JP 2009-158712APatent Literature 8: JP 2009-155450A JP 5 508342 B2 discloses an epoxy resin material containing an epoxy resin and a curing agent. JP 2019 077804 A discloses a one-component resin composition. WO 2013/183303 A1 discloses a curable resin composition containing a curing agent consisting of a polyfunctional epoxy compound having a specific structure, a cyanate ester, and an imidazole compound. JP 2013 216865 A discloses a thermosetting resin filler. Summary of Invention As described above, the cyanate-epoxy composite resin compositions disclosed in Patent Literatures 1 to 5 cannot sufficiently achieve both storage stability and heat resistance. Further, it is known that using a 4-aminophenol-type epoxy resin, as an epoxy resin, in a cyanate-epoxy composite resin composition can achieve a cured product having low viscosity and good physical properties. Inventors, however, conducted further studies to find that, in cases of using a 4-aminophenol-type epoxy resin, as an epoxy resin, in a cyanate-epoxy composite resin composition, there is still room for improvement in terms of storage stability. An objective to be achieved by the present invention is to provide a curable resin composition having excellent storage stability and capable of providing a cured product having excellent heat resistance. As a result of diligent research, Inventors have found that a curable resin composition containing a cyanate ester resin, a specific epoxy resin, and a latent curing agent can achieve the aforementioned objective, thus arriving at the present invention. That is, the present invention provides a curable resin composition containing: (A) a cyanate ester resin; (B) an epoxy resin essentially including a 4-amino-3-methylphenol-type epoxy resin and an aliphatic epoxy resin; and (C) a latent curing agent; wherein the amount of the 4-amino-3-methylphenol-type epoxy resin within the total amount of the epoxy resins is from 20 to 100 mass%, and the amount of the aliphatic epoxy resin within the total amount of the epoxy resins is from 1 to 70 mass%. The present invention also provid