Loading patent…
AssigneeMcGraw-Edison Company
InventorsFred S. Sadler, John Lapp
Estimating the term…
Cellulose material having improved resistance to thermal deterioration and having particular application as insulation material for electrical apparatus. The cellulose material is treated with an aqueous dispersion of a liquid, uncured, crosslinkable thermosetting resin, such as an epoxy resin, and a water soluble, nitrogen-containing compound. During curing of the resin, the cellulose molecules are believed to enter into the crosslinking reaction to provide a treated cellulosic product capable of withstanding the deteriorating action of heat over extended periods of time. A protein material, such as casein or isolated soy protein, can be added to the treating liquid and the protein not only contributes additional nitrogen groups to the treating media to further increase the thermal stability of the cellulose, but also acts as a film former. The thermal stability of the cellulose material can be further improved by the addition of an organic amine, such as melamine, to the treating liquid.
A method of treating cellulose material to increase its physical properties at elevated temperatures, comprising the steps of impregnating the cellulose material with an aqueous treating medium having dispersed therein a liquid uncured thermosetting resin selected from the group consisting of epoxy resins and polyester resins, and an organic amine, evaporating the water from the aqueous medium, and thereafter curing the resin to provide a treated cellulose material having improved physical properties at elevated temperatures.
A method of treating cellulose material to increase its physical properties at elevated temperatures, comprising the steps of impregnating the cellulose material with an aqueous treating medium having dispersed therein a liquid uncured epoxy resin and an organic amine curing agent for said epoxy resin, said medium containing from 1 to 30% by weight of solids, said resin being present in an amount of 5% to 65% by weight of the cellulose material based on 100% solids, said amine being present in a stoichiometric amount necessary to substantially completely cure said resin, evaporating the water from the aqueous medium, and thereafter curing the resin to provide a treated cellulose material having a nitrogen content in the range of 0.3 to 10% by weight of the dry cellulose material.
A treated cellulose fiber product having improved physical properties at elevated temperatures, said product being produced by impregnating a cellulose fiber material with an aqueous treating medium having dispersed therein a liquid uncured thermosetting resin selected from the group consisting of epoxy resins and polyester resins, and an organic amine, evaporating the water from the aqueous medium, and thereafter crosslinking the resin to provide a treated product, containing from 0.3% to 10% by weight of nitrogen based on the weight of the dry cellulose material, said product having sufficient flexibility to be wound in coiled form.
Dependencies are inferred from the claim text.