Gypsum retarder

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Gypsum retarder

Chinese name: gypsum retarder

Properties: white, brown, powder, soluble in water

Method of use: in half water gypsum content of 0.03% to 0.5%

Function: used for stucco gypsum, gypsum

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An overview of the



Gypsum retarder is mainly used in paint, adhesive plaster, gypsum putty, gypsum products made of gypsum building materials, such as gypsum condensation is mainly used to reduce speed. At present commonly used three main retarder, organic acid and its soluble salt, alkaline phosphate and protein retarder. Organic acids and soluble salts main retarder citric acid sodium, citric acid, tartaric acid, tartaric acid potassium and sodium acrylate and acrylic acid, the most studied and the best effect of citric acid and its salt. Dosage of citric acid and its salt in the very hours can achieve strong retarding effect. Phosphate retarder are mainly sodium hexametaphosphate, sodium phosphate polymer, etc.



performance



Gypsum retarder have white, brown, powder, soluble in water.



The influence of the strength of gypsum retarder



1. Incorporating citric acid, sodium phosphate polymer, borax strength of three kinds of gypsum retarder and decreased with the increase of dosage, the changing rule of the dry strength and wet strength and the trend is similar.



2. After incorporating citric acid, dry strength and wet strength of plaster sample lower too. Dry flexural strength in its content is more than o. 07%, sharply reduced; Dry compressive strength when its content is more than 0.05%, sharply reduced; And wet flexural strength is almost in a straight line down, when the dosage of 0.1%, mould gypsum wet flexural strength of only 0.5 MPa.



3. After the incorporation of sodium phosphate polymer, mold plaster the strength of the downtrend is blending citric acid small many, but significantly lower than mixed borax.



4. In the case of the same dosage of retarder, the influence of strength of gypsum has the following pattern: borax < sodium phosphate polymer < citric acid, this is and their effect on the setting time of the same order.



From the point of the influence of the strength of gypsum, borax is three kind of the most suitable retarder retarder; Although many poly sodium phosphate is the negative effect on the strength of gypsum borax is big, but in the case of less dosage of the retarder can also be used to do. If use citric acid for retarder, its content should be controlled in o. below 03%.



Method of use for a half water gypsum (for example)



1, in the half water gypsum content of 0.03% to 0.5%.



2, with the increase of dosage of gypsum retarder, the setting time extended.



3, with the increase of temperature, dosage of gypsum retarder should be appropriate.



4, because of the variety and performance of the gypsum, gypsum retarder may be different, the effect of dosage of before use and then make a decision.



5, when used in stucco gypsum, gypsum retarder of cement mixed with 0.5% can effectively prolong retarded.



Use tables for



Gypsum retarder