Thermosetting epoxy resin composition for the preparation of articles for electrical engineering, and the articles obtained therefrom
A multiple component anhydride-free, thermosetting epoxy resin composition comprising, (A) at least one epoxy resin, and (B) at least one curing agent selected from the group of (b1) a polyetheramine of the formula (1) (Formula (1)), wherein x is a number of from 2 to 8, and (b2) a polyetheramine with at least one terminal end group of the formula (2) (Formula (2)), and (C) at least one epoxy silane, is, in particular, suitable for the manufacture of instrument transformers and dry-type transformers by casting, potting and encapsulation processes, wherein said articles exhibit good mechanical, electrical and dielectrical properties.
1. A multiple component anhydride-free, thermosetting epoxy resin composition comprising:
(A) at least one epoxy resin,
(B) at least one polyetheramine with at least one terminal end group of the formula
(C) at least one epoxy silane, and
(D) 55 wt %-65 wt %, based on the total weight of the thermosetting epoxy resin composition, of a filler selected from selected from the group of quartz sand, quartz powder, silica, aluminium oxide, titanium oxide, zirconium oxide, Mg(OH) 2 , Al(OH) 3 , dolomite [CaMg (CO 3 ) 2 ], AIO(OH), silicon nitride, boron nitride, aluminium nitride, silicon carbide, boron carbide, chalk, calcium carbonate, barite, gypsum, hydromagnesite, zeolite, talcum, mica, kaolin and a mixture thereof,
wherein the at least one polyetheramine and the at least one epoxy resin are present in an amount such that the ratio of active hydrogen equivalents of the at least one polyetheramine to the epoxy equivalents of the at least one epoxy resin are in a range of from 0.75:1 to 1.25:1, wherein no additional curing agent is applied in the composition.
2. The composition according to claim 1 , wherein the at least one epoxy resin (A) has an epoxy equivalent weight of about 170 to about 250 g/eq.
3. The composition according to claim 1 , wherein the at least one epoxy resin (A) is a diglycidylether of bisphenol A.
4. The composition according to claim 1 , wherein the at least one epoxy silane (C) is [3-(2,3-epoxypropoxy)propyl]trimethoxy silane.
5. The composition according to claim 1 , wherein the filler is selected from the group consisting of quartz sand, quartz powder, silica, aluminium oxide, titanium oxide, and a mixture thereof.
6. The composition according to claim 1 , wherein: the at least one epoxy resin (A) is at least one diglycidylether of bisphenol A having an epoxy equivalent weight of about 170 to about 250 g/eq, and the at least one epoxy silane (C) is [3-(2,3-epoxypropoxy) propyl]trimethoxy silane.
7. A process for the preparation of an article for electrical engineering comprising applying the thermosetting epoxy resin composition of claim 1 to the article and curing the thermosetting epoxy resin composition.
8. The process according to claim 7 , wherein the article for electrical engineering is an instrument transformer or a dry-type transformer prepared by casting, potting, or an encapsulation process.
9. The process according to claim 8 , wherein the article for electrical engineering is prepared by automatic pressure gelation (APG), or vacuum casting.
10. The process according to claim 9 , wherein the article for electrical engineering is prepared by vacuum casting.
11. An article for electrical engineering obtained by the process according to claim 7 .
12. The article of claim 11 , wherein the article is an instrument transformer or a dry-type transformer.