2021-12-10 Pageview:471
Coating industry
Properties and advantages:
The additive improves the orientation of effect pigments (e.g. aluminum, mica) and enhances the trigger action. Short-wave defects (speckles, Benard swirls) are minimized and the subsequent leveling of the clear coat is improved. Settling in the container is also reduced.
Recommended use:
CERAFAK 103 is recommended for solvent-borne primers and single-coat metallic topcoats for automotive coatings.
Recommended dosage.
50% of additive (e.g.) based on solid binder.
Inexpensive, water-soluble ammonium dihydrogen phosphate and diammonium hydrogen phosphate and short-chain polyphosphate dumplings (polymerization degree n=10-20) are widely used in most synthetic fiber fabrics such as cellulose fabrics, paper, wood, and polyester. The flame retardant treatment. However, the water-soluble ammonium polyphosphate has strong moisture absorption. The fabric treated by it has a damp feeling. The treated wood has the phenomenon of anti-moisture and blooming in the high humidity environment. Polyvinyl acetate glue is used for the wood. The bonding performance has an impact. However, polyethylene copolymer wax high-molecular-weight ammonium polyphosphate (n>20), due to its good thermal stability and low hygroscopicity, is widely used in fire-resistant coatings. If used in the above-mentioned fields, it can overcome the shortcomings of low molecular weight substances.
The flame-retardant effect of organophosphate depends to a large extent on the chemical structure of its flame-retardant substance. For cellulose or other polyhydroxy compounds or oxygen-containing organic polymers, the burning mechanism is: in the case of combustion, phosphide decomposes to release phosphoric acid and one or more organic phosphoric acids. These acids have a covering effect on the one hand; On the other hand, it is mainly used as a strong acid, which can cause the dehydration of polyhydroxy polymer into carbon, and the formed carbon layer has the function of heat and oxygen barrier, so as to achieve the flame retardant effect.
Thermal polymerization of phosphoric acid to polyphosphoric acid
Dehydration of fiber cord into charcoal
However, for hydrocarbon-based thermoplastic polymers, due to their thermal stability, the flame retardancy of phosphides may be caused by the covering effect of heavy vapor volatilized after heating.
The mechanism of action of organic flame retardants is to capture active free radicals. At high temperatures, halogen atoms generated by the decomposition of halogen-containing flame retardants react with polymers to generate hydrogen halide, and then react with highly reactive free radicals ·OH and ·H to form water or hydrogen, which interrupts the chain oxidation process and slows down the combustion. Even stopped. Australian flame retardants can be divided into reactive type and additive type from the method of use; from the composition, they can be divided into aliphatic, aromatic and alicyclic compounds. For example, tetrabromobisphenol A contains active hydroxyl groups, which can participate in polycondensation or esterification reactions. Another example is bis(2,3-dibromopropyl) fumarate itself contains double bonds, which can participate in graft polymerization, chain polymerization and other reactions; added bromine flame retardants require good compatibility with materials, Less impact on the physical and chemical properties of the material, low volatility, odorless, small dosage, significant flame retardant effect, low toxicity, no corrosion, no pollution, and low price. The following introduces some of the flame retardant products and their selections that are currently used more in fire retardant coatings.
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