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JP-2026075033-A - Latent curing agent and thermosetting epoxide composition containing the same

JP2026075033AJP 2026075033 AJP2026075033 AJP 2026075033AJP-2026075033-A

Abstract

[Problem] The object of the present invention is to provide a liquid latent curing agent with high storage stability and a curable epoxide composition using the same. [Solution] The above problem can be solved by a latent curing agent comprising (A) a compound obtained by reacting (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton, (b) an alcohol having 1 to 20 carbon atoms, and (c) an aliphatic isocyanate compound having one or more isocyanate groups; or (B) a compound obtained by reacting (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton, and (c) an aliphatic isocyanate compound having one isocyanate group. [Selection Diagram] None

Inventors

  • 大村 飛鳥

Assignees

  • 株式会社T&K TOKA

Dates

Publication Date
20260507
Application Date
20250415
Priority Date
20241021

Claims (11)

  1. (A) (a) Bicyclic compounds having an amidine skeleton, or compounds having a guanidine skeleton, (b) an alcohol having 1 to 20 carbon atoms, and (c) an aliphatic isocyanate compound having one or more isocyanate groups. Compounds obtained by reacting (B) (a) a bicyclic compound having an amidine skeleton, or a compound having a guanidine skeleton, and (c) an aliphatic isocyanate compound having one isocyanate group; A latent curing agent containing [the specified ingredient].
  2. In (A) above, the molar ratio of the aliphatic isocyanate compound to the bicyclic compound having an amidine skeleton or the compound having a guanidine skeleton is 0.01 to 5.0, and the molar ratio of the alcohol having 1 to 20 carbon atoms is 0.05 to 10.0. The latent curing agent according to claim 1, wherein in (B) above, the molar ratio of the bicyclic compound having an amidine skeleton or the compound having a guanidine skeleton to the aliphatic isocyanate compound is 0.01 to 5.0.
  3. In (A) above, with respect to the total amount of latent curing agent, (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton is 1% to 50% by mass, (b) an alcohol having 1 to 20 carbon atoms is 10% to 70% by mass, and (c) an aliphatic isocyanate compound having one or more isocyanate groups is 10% to 70% by mass. In (B) above, with respect to the total amount of latent curing agent, (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton is 1% to 50% by mass, and (c) an aliphatic isocyanate compound having one or more isocyanate groups is 40% to 99% by mass. The latent curing agent according to claim 1.
  4. (A) (a) Bicyclic compounds having an amidine skeleton, or compounds having a guanidine skeleton, (b) an alcohol having 1 to 20 carbon atoms, and (c) an aliphatic isocyanate compound having one or more isocyanate groups. Reacting the following: (B) (a) a bicyclic compound having an amidine skeleton, or a compound having a guanidine skeleton, and (c) an aliphatic isocyanate compound having one isocyanate group, To cause a reaction; A method for producing a latent curing agent, characterized by the following.
  5. In (A) above, the molar ratio of the aliphatic isocyanate compound to the bicyclic compound having an amidine skeleton or the compound having a guanidine skeleton is 0.01 to 5.0, and the molar ratio of the alcohol having 1 to 20 carbon atoms is 0.05 to 10.0. The method for producing a latent curing agent according to claim 3, wherein in (B) above, the molar ratio of the aliphatic isocyanate compound to the bicyclic compound having an amidine skeleton or the compound having a guanidine skeleton is 0.01 to 5.0.
  6. In (A) above, with respect to the total amount of latent curing agent, (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton is 1% to 50% by mass, (b) an alcohol having 1 to 20 carbon atoms is 10% to 70% by mass, and (c) an aliphatic isocyanate compound having one or more isocyanate groups is 10% to 70% by mass. In (B) above, with respect to the total amount of latent curing agent, (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton is 1% to 50% by mass, and (c) an aliphatic isocyanate compound having one or more isocyanate groups is 40% to 99% by mass. A method for producing a latent curing agent according to claim 4.
  7. A thermosetting epoxide composition comprising an epoxide compound having an average of more than one epoxy group in its molecule, and a latent curing agent according to any one of claims 1 to 3.
  8. In (A) above, with respect to the total amount of the thermosetting epoxide composition, (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton is 0.2% to 10% by mass, (b) an alcohol having 1 to 20 carbon atoms is 2% to 14% by mass, and (c) an aliphatic isocyanate compound having one or more isocyanate groups is 2% to 14% by mass. In (B) above, with respect to the total amount of the thermosetting epoxide composition, (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton is 0.2% to 10% by mass, and (c) an aliphatic isocyanate compound having one or more isocyanate groups is 8% to 19.8% by mass. The thermosetting epoxide composition according to claim 7.
  9. A cured product obtained by curing the thermosetting epoxide composition according to claim 7 or 8.
  10. A paint comprising the thermosetting epoxide composition according to claim 7 or 8.
  11. An adhesive comprising the thermosetting epoxide composition according to claim 7 or 8.

Description

This invention relates to a latent curing agent and a thermosetting epoxide composition. According to this invention, a liquid latent curing agent with excellent stability can be provided. Latent curing agents for curable epoxide compositions, which have good storage stability and harden when heated, are in high demand because they reduce the labor of frequent mixing. Most conventional latent curing agents are solid and were used after being finely ground by crushing or other means (Patent Documents 1 and 2). On the other hand, some latent curing agents are also available in liquid form. For example, 2-ethyl-4-methylimidazole has a melting point of approximately 41°C and can be used in liquid form (Patent Document 3). Special Publication No. 6-6620Special Publication No. 6-6621Japanese Patent Publication No. 2010-168516 [1] Latent curing agent The latent curing agent of the present invention includes a compound obtained by reacting (A) (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton (hereinafter sometimes referred to as component a), (b) an alcohol having 1 to 20 carbon atoms (hereinafter sometimes referred to as component b), and (c) an aliphatic isocyanate compound having one or more isocyanate groups (hereinafter sometimes referred to as component c). Furthermore, the latent curing agent of the present invention includes a compound obtained by reacting (B) (a) a bicyclic compound having an amidine skeleton or a compound having a guanidine skeleton (hereinafter sometimes referred to as component a), and (c) an aliphatic isocyanate compound having one isocyanate group (hereinafter sometimes referred to as component c). The latent curing agent of the present invention is a main component used for curing curable epoxide compositions and is different from a curing catalyst used as an auxiliary component. 《Bicyclic compounds with an amidine skeleton (a)》 The amidine skeleton in the aforementioned bicyclic compound having an amidine skeleton has a structure represented by the following formula (1). The bicyclic compound having the amidine skeleton is not particularly limited as long as it has the amidine skeleton and is bicyclic, but the following formula (2): Diazabicycloundecene represented by the following formula (3): 1,8-diazabicyclo[5.4.0]undec-7-ene; DBU®, or formula (3) below: One example is diazabicyclononene (1,5-diazabicyclo[4.3.0]non-5-ene; DBN), represented by . Therefore, bicyclic compounds with an amidine skeleton contain a nitrogen atom and are heterobicyclic compounds with an amidine skeleton. Compounds containing a guanidine skeleton (a) The guanidine skeleton in the compound having the guanidine skeleton is given by the following formula (4): The structure is represented by the following. Compounds having a guanidine skeleton are not limited to those with the following general formula (5): (In the formula, R is independently an alkyl group having 1 to 6 carbon atoms.) It is a compound represented by the following formula (6): Examples include tetramethylguanidine (1,1,3,3-Tetramethylguanidine; TMG), or 1,3-diphenylguanidine, 1,2,3-tris(tert-butoxycarbonyl)guanidine, phenylbiguanide, or 1,3-di-o-tolylguanidine, but 1,3-diphenylguanidine, 1,2,3-tris(tert-butoxycarbonyl)guanidine, phenylbiguanide, or 1,3-di-o-tolylguanidine are preferred. The latent curing agent of the present invention may contain both a bicyclic compound having an amidine skeleton and a compound having a guanidine skeleton. A latent curing agent containing both components a can also exhibit the excellent stability that is the effect of the present invention. Alcohols with 1 to 20 carbon atoms (b) Alcohols with 1 to 20 carbon atoms include primary alcohols, secondary alcohols, and tertiary alcohols. Primary alcohols include methanol ( C1 ), ethanol ( C2 ), propan-1-ol ( C3 ), butan-1-ol ( C4 ), pentan-1-ol ( C5 ), hexane-1-ol ( C6 ), heptane-1-ol ( C7 ), octan-1-ol ( C8 ), nonane-1-ol ( C9 ), decane-1-ol ( C10 ), undecane-1-ol ( C11 ), dodecane-1-ol ( C12 ), tridecane-1-ol ( C13 ), tetradecane-1-ol ( C14 ), pentadecane-1-ol ( C15 ), hexadecane-1-ol ( C16 ), heptadecane-1-ol ( C17 ), octadecane-1-ol ( C18 ), nonadecane-1-ol (C15). Examples include 19 ), or icosan-1-ol ( C20 ). Examples of secondary alcohols include propan-2-ol ( C3 ), butan-2-ol ( C4 ), pentan-2-ol ( C5 ), hexane-2-ol ( C6 ), heptan-2-ol ( C7 ), cyclohexanol ( C6 ), or 2-methylbutan-1-ol ( C5 ). Examples of tertiary alcohols include 2-methylpropan-2-ol ( C4 ), 2-methylbutan-2-ol ( C5 ), 2-methylpentan-2-ol ( C6 ), 2-methylhexane-2-ol ( C7 ), 2-methylheptan-2-ol ( C8 ), 3-methylpentan-3-ol ( C6 ), or 3-methyloctane-3-ol ( C9 ). Alkyl groups contained in alcohols having 1 to 20 carbon atoms include linear alkyl groups, branched alkyl groups, or cyclic alkyl groups. Aliphatic isocyanate compounds (c) The aliphatic isocyanate compound is not particularly limited as long as it has one or more isocyanate groups, but e