Dry plaster mix comprising aggregate, clay, cellulose derivative and amine aldehyde resin

Claim 1

A DRY PLASTER MIX WHICH UPON ADMIXTURE WITH WATER FORMS A WET PLASTIC TROWELABLE OR SPRAYABLE MASS ADHERENT TO A SURFACE TO BE PLASTERED AND WHICH UPON DRYING AND SETTING FORMS A CELLULAR HEAT AND SOUND INSULATING LAYER, SAID MIXTURE CONSISTING ESSENTIALLY OF ABOUT 100 PARTS BY WEIGHT OF LIGHTWEIGHT, POROUS MINERAL AGGREGATE HAVING AN APPARENT DENSITY NOT GREATER THAN ABOUT 15 POUNDS/CUBIC FOOT, FROM ABOUT 5 TO ABOUT 25 PARTS BY WEIGHT OF BENTONITE, FROM ABOUT 0.5 TO ABOUT 3 PARTS BY WEIGHT OF A WATER-SOLUBLE CELLULOSE DERIVATIVE SELECTED FROM THE GROUP CONSISTING OF SODIUM CARBOXY METHYL CELLULOSE AND METHYL CELLULOSE, AND FROM ABOUT 0.07 TO ABOUT 0.70 PARTS BY WEIGHT OF A WATER SOLUBLE CONDENSATION PRODUCT OF AN ALDEHYDE WITH A MATERIAL SELECTED FROM THE GROUP CONSISTING OF UREA AND MELAMINE, WHICH WHEN SAID DRY MIXTURE IS MIXED WITH WATER WILL REACT WITH SAID WATER SOLUBLE CELLULOSE DERIVATIVE TO FORM AT AMBIENT TEMPERATURE A WATER INSOLUBLE FILM.