Curing agent for thermosetting epoxy resins, and a process for the preparation of insulation systems for electrical engineering

Patent metadata

Field	Value
Publication number	US-10851201-B2
Application number	US-201615575270-A
Country	US
Kind code	B2
Filing date	May 11, 2016
Priority date	May 19, 2015
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

The invention relates to a curing agent for thermosetting epoxy resins comprising (a) at least one aromatic amine containing at least two amino groups, and (b) at least one clathrate compound obtained by reacting a tetrakisphenol of the formula (1), or a 9,9-Bis(4-hydroxyphenyl)fluorene of formula (2), as the host molecule, and an imidazole or an imidazolium derivative as the guest molecule, wherein the substituents are as defined in the description, and n is the number 0, 1, 2 or 3, which can advantageously be used for the curing of epoxy resins. In addition, the invention also relates to a process for the preparation of a cured article, a process for the preparation of insulation systems for electrical engineering and a cured article obtained by the processes.

First claim

What is claimed is:

1. A curing agent for thermosetting epoxy resins comprising
(a) at least one aromatic amine containing at least two amino groups, and
(b) at least one clathrate compound obtained by reacting:
9,9-Bis(4-hydroxyphenyl)fluorene of formula

as the host molecule and an imidazole or an imidazolium derivative as the guest molecule, wherein,
R 10 , R 11 , R 12 , R 13 , R 14 and R 15 are each hydrogen.

2. The curing agent according to claim 1 , wherein the guest molecule of the clathrate compound (b) is selected from the group consisting of imidazole, 1-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-n-propylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-isopropyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenyl imidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 1,2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-dodecyl-2-methylimidazole, 1-cyanoethyl-2-phenyl-4,5-di(2-cyanoethoxy)methylimidazole, and mixtures thereof.

3. The curing agent according to claim 1 , wherein the guest molecule of the clathrate compound (b) is 2-ethyl-4-methylimidazole or 2-methylimidazole.

4. A process for the preparation of a cured article, wherein a multiple component thermosetting epoxy resin composition according to claim 1 is used.

5. The cured article obtained by the process according to claim 4 .

6. The curing agent according to claim 1 , wherein the at least one aromatic amine is 3,5-diethyl-2,4-diaminotoluene, 3,5-diethyl-2,6-diaminotoluene, or a mixture thereof.

7. A multiple component thermosetting epoxy resin composition comprising
(A) at least one epoxy resin, and
(B) at least one curing agent comprising
(a) at least one aromatic amine containing at least two amino groups, and
(b) at least one clathrate compound obtained by reacting:

9,9-Bis(4-hydroxyphenyl)fluorene of formula

as the host molecule and an imidazole or an imidazolium derivative as the guest molecule, wherein,
R 10 , R 11 , R 12 , R 13 , R 14 and R 15 are each hydrogen,
wherein the clathrate compound is present in the multiple component thermosetting epoxy resin composition in an amount ranging from 1 to 5 parts by weight based on 100 parts by weight of the at least one epoxy resin.

8. The multiple component thermosetting epoxy resin composition according to claim 7 , wherein
(A) the epoxy resin comprises a diglycidylether of bisphenol A having an epoxy equivalent weight of about 180 to about 190, and
(B) the curing agent consists of
(a) 18 to 26 parts by weight of diethyltoluene diamine, and
(b) the clathrate compound.

9. The multiple component thermosetting epoxy resin composition according to claim 7 , further comprising
(C) at least one filler selected from the group consisting of quartz sand, quartz powder, silica, aluminium oxide, titanium oxide, zirconium oxide, Mg(OH) 2 , AI(OH) 3 , dolomite [CaMg (CO 3 ) 2 ], AI(OH) 3 , AIO(OH), silicon nitride, boron nitrides, aluminium nitride, silicon carbide, boron carbides, dolomite, chalk, calcium carbonate, barite, gypsum, hydromagnesite, zeolites, talcum, mica, kaolin and wollastonite, which may optionally be coated with a silane or a siloxane.

10. A cured article comprising the reaction product of the multiple component thermosetting epoxy resin composition according to claim 7 .

11. A process for the preparation of an insulation system for electrical engineering by a casting, potting, encapsulation, or an impregnation process, wherein a multiple component thermosetting epoxy resin composition is used, said epoxy resin composition comprising
(A) at least one epoxy resin, and
(B) at least one curing agent, comprising
(a) at least one aromatic amine containing at least two amino groups, and
(b) at least one clathrate compound obtained by reacting:

9,9-Bis(4-hydroxyphenyl)fluorene of formula

as the host molecule and an imidazole or an imidazolium derivative as the guest molecule, wherein,
R 10 , R 11 , R 12 , R 13 , R 14 and R 15 are each hydrogen.

12. The process according to claim 11 , wherein the insulation system for electrical engineering is prepared by automatic pressure gelation (APG).

Assignees

• Huntsman Int Llc

Inventors

• Beisele Christian
• Colliard Sophie
• Schoenenberger Catherine

Classifications

• C08G59/56

  together with other curing agents · CPC title

• 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} · CPC title

• H01H33/021

  Use of solid insulating compounds resistant to the contacting fluid dielectrics and their decomposition products, e.g. to SF6 · CPC title

• C08G59/621

  Phenols · CPC title

• C08G59/5033 Primary

  aromatic · CPC title