Gypsum plaster is widely used in dry-mixed mortar products. Whether it is hand-applied plaster or machine-applied plaster, starch ether plays a very important role in it. The influence of starch ether on the thickening of freshly mixed mortar can provide thickening effect for plaster, so that plaster can quickly reach a suitable consistency during construction. Starch ether is a very effective thickener for gypsum plaster. Very low starch ether content, usually in the range of 0.03%-0.1%, can already achieve a good thickening effect, so that the plaster can be used immediately, and a retarder is used to extend the overall working time.
In the traditional pure plaster, when the plaster and water are mixed, the viscosity increases rapidly, making the plaster have the expected consistency and suitable for the application in a very short period of minutes, but the operating time is too short . The addition of retarder prolongs the working time of the plaster, but it is necessary to wait until the consistency reaches the required interval to be suitable for the application, and the operating time is still relatively short.
The addition of retarder prolongs the working time of the plaster, but it is necessary to wait until the consistency reaches the required interval to be suitable for the application, and the operating time is still relatively short. When starch ether and retarder are added to the product at the same time, the required consistency can be reached immediately, and the resulting plaster can be used immediately. The operable time can be set by the amount of retarder to extend the operable time. The content and type of starch ether determine the degree of thickening of plaster. Through special chemical treatment of starch ether, lower dosage can be used to obtain higher thickening effect in both alkaline and neutral systems.