Gypsum retarder

Application

Compared with ordinary Portland cement, building gypsum has a short setting and hardening time. It loses fluidity and hardens within a few minutes after adding water. The operating time is short and cannot meet the needs of construction. Therefore, in the development process of gypsum-based building materials, gypsum retarders are generally added to obtain a more suitable operating time to improve the construction performance of gypsum-based building materials. Gypsum retarders can prolong the hydration time of gypsum from hemihydrate gypsum to dihydrate gypsum, thereby prolonging the setting time of gypsum, perfectly solving the problem of gypsum solidifying too quickly. It is mainly used in gypsum building materials made of gypsum self-leveling, plastering gypsum, bonding gypsum, gypsum putty, gypsum products, etc.

01

What are the effects of gypsum retarders?

⑴ Reduce the solubility of hemihydrate gypsum;

⑵ Slow down the dissolution rate of hemihydrate gypsum;

⑶ Adsorb ions on the surface of growing dihydrate gypsum crystals and combine them into the lattice;

⑷ Form a complex to limit the diffusion of ions near dihydrate gypsum crystals.

02

Three common gypsum retarders

1Organic acid and its soluble salt retarders

Organic acid and soluble salt retarders mainly include citric acid, sodium citrate, tartaric acid, potassium tartrate, acrylic acid and sodium acrylate, etc. Organic acids complex calcium ions, hinder the dissolution of hemihydrate gypsum, reduce the supersaturation of the liquid phase, slow down the rate of crystal nucleation during the hydration induction period of gypsum, and achieve a retarding effect.

2Alkaline phosphate retarders

Alkaline phosphate retarders mainly include sodium hexametaphosphate and sodium polyphosphate. Sodium hexametaphosphate forms poorly soluble calcium hexametaphosphate with calcium ions in hemihydrate gypsum, which adheres to the surface of hemihydrate gypsum and hinders the hydration and further crystal growth of hemihydrate gypsum.

3Protein gypsum retarders

Protein retarders are a new type of gypsum retarder, which can be divided into protein hydrolyzate, amino acid condensation polymer, etc. Its retarding mechanism: protein retarders form colloids after being dissolved in water, adsorbed on the surface of dihydrate gypsum, forming a layer of colloid film, which hinders the further growth of gypsum crystals. At the same time, due to the adsorption and protective effect of protein colloids, although protein colloids inhibit the growth of gypsum crystals, they do not change the crystal morphology and have little effect on the strength of gypsum.

Advantages of protein gypsum retarders

APPLICATION ADVANTAGE

Protein gypsum retarders can reduce the loss of gypsum strength. The relationship between the retarding time and the amount of retarder added is in a good linear relationship, and they have gradually become the new favorite of gypsum retarders. Protein retarders are mostly macromolecular polymers synthesized from natural hydrolyzed proteins or amino acids. The raw materials are widely available, non-toxic and harmless, and environmentally friendly. They are the trend of green and environmentally friendly development of building additives.

KDR-30 protein gypsum retarder

Kdr-30 gypsum retarder is a protein retarder equivalent to Retardan-200P with a special molecular structure synthesized from a variety of amino acids independently developed by Huaxuan High-tech. It is a new generation of environmentally friendly retarder products with excellent characteristics such as low dosage, good retarding effect, and good dispersibility. It has good adaptability to various gypsums, and the setting time of gypsum can be adjusted according to needs. At the same time, it does not affect the strength of the gypsum hardened body. It is suitable for various gypsum-based mortars and gypsum prefabricated parts, exerting excellent performance and meeting various application requirements.

Strong retarding effect: It can play a good retarding effect at a low dosage, and the setting time is controllable.

High dispersibility: It has excellent dispersing ability, can be quickly adsorbed, reduce mixing time, give the material system excellent workability and construction, improve construction efficiency and meet different construction requirements.

High adaptability: It has excellent adaptability with various cement-based systems, and is well compatible with other functional admixtures, and does not reduce the application performance under various conditions.

Early strength and high strength: It has excellent early strength and strengthening effects, and the strengthening effect is significant under the same conditions. Under the same demand, the dosage can be reduced.

High durability: It enhances the density of the hardened slurry, improves shrinkage and creep properties, reduces cracks, enhances impermeability, erosion resistance and chloride ion penetration resistance, and improves durability.

Green and environmentally friendly: It does not contain harmful substances, is safe and environmentally friendly, and is an environmentally friendly material.

Application Field- APPLICATION FIELD- This product has excellent adaptability and is suitable for various natural and industrial by-product gypsum-based material systems.

·Gypsum-based self-leveling mortar;

·Plastering gypsum, masonry gypsum, painting gypsum, caulking gypsum, gypsum putty, etc.;

·Gypsum prefabricated parts, gypsum blocks, gypsum boards and other products;

·Other gypsum application areas.