2021-11-24 Pageview:390
TMG 612 can be used as a drying agent for inks and coatings. Compared with traditional zinc naphthenate, it has light color, low odor and high content. TMG 612 has stable acid value and molecular weight, excellent storage stability, and has good properties in light-colored paints, which can reduce the color and improve the gloss of the paint film, and is an upgrade of zinc naphthenate. TMG 612 can also be used as a catalyst for polyurethane coatings and elastomers. Compared to organotin catalysts, TMG 612 shows a longer service life and lower catalytic activity in two-component systems.
The molecular formula and structural formula of ammonium polyphosphate: (NH)a-2Pa Osa-1 (general formula), when n is large enough, it can be written as (NHa POs) a.
Its physical properties are as described in the section of ammonium polyphosphate in the flame retardant part of intumescent fire protection system. It is used in coatings, rubber, plastics and other materials without affecting the physical and chemical properties of the materials. It has low toxicity, LD50≥10g/kg, and is safe to use. It is one of the most important high-efficiency phosphorus-based inorganic flame retardants. The hydrolysis rate of APP is related to the particle size, pH value and temperature. When the particle size increases from 1mm to 3mm, the hydrolysis rate decreases by 2 to 3 times. Solubility (phosphomolybdenum blue colorimetric method): 0.9g/100gHO (20℃, 2h), pH value (10% APP suspension): 5.8, P content (weight method): P%=27.36(P2O;%=62.70 ), N content (kjeldahl method): N%=12.3, thermal analysis: 34℃~80℃~134℃ endothermic: 271℃~349℃~377℃ exothermic, 100℃ weight loss 7.5%, 400℃ weight loss 41% , 578℃ weight loss is 50%.
The flame retardant effect of APP is the same as that of other ammonium phosphates, anti-scratch agent but does not have the disadvantages of other ammonium phosphates. It is widely used due to its good thermal stability, higher content of P and N, low water solubility, and non-moisture absorption. APP flame retardant, carbonizing agent (pentaerythritol, etc.), foaming agent (melamine, etc.) are used in intumescent fire retardant coatings. It decomposes when exposed to fire and generates phosphoric acid first. When H:PO is above 300℃, it is extremely unstable and will be further dehydrated. Generate polyphosphoric acid or polymetaphosphoric acid, dehydrate and carbonize the carbonizing agent, bubble the foaming agent, release non-combustible gas, carbonize and expand the coating film to form a honeycomb insulation layer, which has a significant flame retardant effect.
The carbonized layer covers the surface of the substrate, insulates the air, makes the combustion chamber breathe, and its thermal conductivity is poor, which can prevent the flame from spreading; the released water vapor, ammonia, HCI and other non-combustible gases can reduce the temperature of the system and dilute the oxygen concentration in the air. The fireproof coating made of APP has good film-forming properties, excellent physical and chemical properties of the coating film, does not absorb moisture, has the same flame retardant effect after water immersion, and can be used in humid environments.
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