Application research of natural rheology-modified guar gum for water-based fire retardant coatings

Natural rheology modified guar gum in Waterborne fire retardant coatingsThe application performance of There is improvement, with superior leveling and obvious price advantage, low production cost, and the performance of water-based fire retardant coatings are in line with national standards.

Since Rhoplex AC-33, the world's first pure acrylic emulsion, was synthesized by Rohm and Haas in 1953, cellulose ethers have been Its excellent water retention, workability and thickening efficiency play an important role in the application of water-based coatings. Cellulose ethers are composed of glucose, but the connection between glucose units is β(1-4) glycosidic bonds. Cellulose does not contain branches. The spatial conformation of cellulose is ribbon-like, and the sugar chains are stacked together through hydrogen bonds to form a tight lamellar structure, which makes cellulose have strong mechanical strength and supports and protects the organism. Cellulose can be used in water-based fire retardant coatings after etherification with liquid caustic soda, methyl chloride, ethylene oxide, etc.

Guar gum, English name "guar gum" (galactomannan) is a kind of natural bean High molecular carbohydrate polymers isolated from the seeds of Cyampop is tetragonolobus. Guar gum uses mannan as the main molecular chain and D-galactopyranosyl as the branched chain, wherein the ratio of mannose to galactose units is 2:1. Guar gum dissolves in both hot and cold water. Because of its low-cost and high-efficiency emulsification and thickening properties, guar gum has been widely used in oilfield drilling, papermaking, textiles, cosmetics and food.

Guar gums modified by hydroxyethyl or hydroxypropyl, etc., have been used as water-based fire retardant coatings in Europe The thickening agent replaces the traditional expensive hydroxyethyl cellulose ether, and obtains good economic and social benefits. Guar gum used as thickener can not only replace or partially replace traditional hydroxyethyl cellulose ether, but also has a good improvement effect on latex paint. good leveling and good film-forming effect.

Some manufacturers have been in contact with guar gum products before, but there are objective factors such as price instability in the early products. PetroChina has established a guar gum production line with an annual output of 5,000 tons to meet customer needs.

raw materials

Main technical indicators of guar gum and hydroxyethylcellulose

Preparation of aqueous solutions of guar gum and hydroxyethylcellulose

This test uses a 2% aqueous solution. First weigh the calculated amount of water, add the specified amount of guar gum or cellulose under stirring, and after stirring evenly, add 2 drops of AMP-95 to adjust the pH value to 8-9, further increase the stirring speed, and stir until the system Semi-viscous liquid in translucent state, set aside.

Comparison of storage stability of 2% aqueous solution

Storage stability of prepared 2% aqueous guar gum and hydroxyethyl cellulose solution at 30℃ For comparison, the results are shown in Table 3.

250HBR and guar gum to make coatings performance and cost comparison

Petroleum 28000, a representative product of natural rheological additives for water-based fireproof coatings, is used as a substitute or partial substitute for rheological additives in the manufacture of coatings Importing HEC is entirely possible, with a clear price advantage. For a manufacturer with an annual output of 5,000 tons, the annual cost savings can reach about 200,000 yuan, and the economic value is obvious. CNPC guar gum has excellent leveling properties, and at the same time, due to its special structure, it can save part of the emulsion and help the film formation of the coating. The final coating film has good water resistance and scrub resistance.