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Curing Agents for Epoxy Resins

IP.com Disclosure Number: IPCOM000076098D
Original Publication Date: 1972-Jan-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hurd, CD: AUTHOR [+2]

Abstract

In using epoxy resins, it is desirable to incorporate curing agents which have long shelf life and good heat and chemical resistance in addition to good curing characteristics. It is also desirable to be able to form a B-stage epoxy resin system including a curing agent, which system has good shelf life, and which system is additionally characterized by thermal and mechanical stability.

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Curing Agents for Epoxy Resins

In using epoxy resins, it is desirable to incorporate curing agents which have long shelf life and good heat and chemical resistance in addition to good curing characteristics. It is also desirable to be able to form a B-stage epoxy resin system including a curing agent, which system has good shelf life, and which system is additionally characterized by thermal and mechanical stability.

A curing agent of 4, 4'-methylenedianiline (MDA) and m-phenylenediamine (MPDA) in a ratio of 2 parts to 1, by weight, meets these requirements. The MDA/MPDA curing agent is prepared by melting the ingredients to form a eutectic mixture. While a 2:1 ratio is preferred, this ratio may be varied.

Suitable B-staged epoxies can be prepared by mixing approximately 100 parts of bisphenol A-type epoxy resin having an epoxide equivalent of about 170 to 200 with 19 parts, by phr, of this curing agent. Variation of the amount of curing agent between about 17 to are mixed thoroughly and then maintained at a temperature of about 62 degrees to 80 degrees F for at least about 16 hours. Subsequently, the material is found to be B-staged and is ready for use or storage. The B-stage resin can be dissolved in a solvent, such as methyl ethyl ketone and cellosolve acetate, for example, so that it may be sprayed or coated on a workpiece and dried. The coated part may then be allowed to sit for a month or more before final use and curing.

This B-stage system is sufficientl...