Physical indexes of adhesion promoter LD9051

Product appearance : Clear and transparent
Functionality (average): 3
Color, G(Gardner’s index): <5G
Viscosity, cps@ 25℃: 250-450
Acid value, mgKOH/g: 120-180

Diammonium hydrogen phosphate Diammonium hydrogen phosphate is a colorless crystal or white crystalline powder, molecular formula (NH) zH PO, relative molecular mass 132.06, relative density 1.619, easily soluble in water, the aqueous solution is weakly alkaline, insoluble in alcohol and acetone , The solubility in 100mL water: 42.9g at 0℃, 106g at 70℃. When heated to 155°C, it decomposes and loses a paraffin wax emulsion formula part of ammonia to become ammonium dihydrogen phosphate. It is unstable in the air and gradually loses ammonia and becomes ammonium dihydrogen phosphate. Ammonium dihydrogen phosphate is stable in the air. It melts at 190°C and separates ammonia and water to form a mixture of ammonium metaphosphate (NH PO,) and phosphoric acid. A small part of it decomposes at about 100°C, and the aqueous solution is acidic.

Because diammonium hydrogen phosphate contains phosphorus and nitrogen, due to the synergistic effect of P-N, it has a very good flame retardant effect. It is mainly used as an expansion catalyst in intumescent fire retardant coatings, and also acts as a blowing agent and an inorganic flame retardant additive. Generally used together with carbonizing agent (starch, pentaerythritol, etc.) and foaming agent (melamine, dicyandiamide, etc.). It decomposes into phosphoric acid and metaphosphoric acid and polymerizes into polymetaphosphoric acid when exposed to fire. It has a strong dehydration effect, which can dehydrate and carbonize the carbonizing agent and release ammonia gas. Good flame retardant effect. However, due to its poor thermal stability, high water solubility, and easy moisture absorption, it is not suitable for use in humid environments. In recent years, it has been gradually replaced by ammonium polyphosphate.

Ammonium polyphosphate (APP for short) is a white (crystalline or amorphous) powder. When n is large enough, the molecular formula can be written as (NH{POs) n. When n=10-20, the relative molecular mass is about 1000~2000; when n>20, the relative molecular mass>2000, it is an unbranched long-chain polymer. Depending on the degree of polymerization (n), it can be divided into two types: water-soluble (n=10-20) and water-insoluble (n>20).

Commonly used crystalline APP is water-insoluble long-chain ammonium polyphosphate, which has five variants from I to V. APP contains high phosphorus and nitrogen content, PN system has a synergistic effect, and has good flame retardant effect; the product has good thermal stability, and the decomposition temperature is higher than 250℃, and it is completely decomposed at about 750℃; low water solubility, low moisture absorption, 10gAPP 15℃ When soluble in 100g water, the solubility is less than 2g in 1 hour, the product fineness can reach 300 meshes or more, the relative density is low, about 1.24, and the dispersibility is good; the product is close to neutral, has good chemical stability, and can not be mixed with any other substances. It can be used in intumescent fireproof coatings without affecting its physical and chemical properties. It is one of the most important high-efficiency phosphorus-based inorganic flame retardants. It is currently the most widely used and most used inorganic flame retardant additive in intumescent fireproof coatings. , It mainly plays the role of catalyst, foaming agent and flame retardant for the formation of carbon foam layer in fire retardant coatings.