GB703408A - Improvements in or relating to a process of making synthetic resins and the productsresulting therefrom - Google Patents

Abstract

A synthetic resin is made by etherifying at least one phenolic hydroxyl group of a natural catechol tanning agent with mono-chloro or -bromo-acetic or propionic acid, by reaction in an alkaline medium with not more than 2 mols. of the acid per mol of the tanning agent, condensing the product thus formed with formaldehyde, and thereafter etherifying at least one of the remaining phenolic hydroxyl groups by reaction with an aralkyl halide in an alkaline aqueous medium. The natural tanning agents specified are quebracho extract, wattle, cutch and mangrove. Benzyl chloride is the preferred aralkyl chloride. In the example monochloracetic acid is added to a cooled mixture of quebracho extract and aqueous caustic soda followed by heating of the mix to 90-95 DEG C. for 1/2 hour. To this solution, after cooling, is added further caustic soda and aqueous formaldehyde, the mixture being heated, but cooled again for the addition of benzyl chloride and thereafter heated. A solution of caustic soda and sodium hydrosulphite is added to the mixture and the whole mass, while still hot, is poured into trays and solidified. The free resin may be obtained by acidification with, e.g. hydrochloric or sulphuric acid. The resins, which are soluble in alkalis and solvents such as benzene, toluene, methanol, ethanol and propanol, may be used for making compositions for coating, e.g. leather, cloth and paper, as disclosed in Specification 703,409. Specification 703,407 also is referred to.