People who often use the forming liquid silica gel raw material to turn the mold or pour the sealing often encounter the phenomenon of not curing or contact surface not curing and sticky. The reply is caused by the platinum catalyst poisoning. For people who just touch the forming liquid silica gel and not many people to hear such a professional term is confused. Here is a deep analysis of the reason why the silicone platinum catalyst is poisoned and does not cure.

Definition of poisoning: catalyst due to the action of certain substances to make catalytic activity decline or loss of the phenomenon known as catalyst poisoning. These substances are called toxins. Toxins are usually impurities brought into the reaction material, or some impurities in the catalyst itself; Reaction products or by-products may also poison the catalyst.

Poisoning principle: catalyst in the original family containing a small amount of impurities, or strong adsorption (mostly chemical adsorption) on the active center, or with the active center chemical action, into other substances, so that the active center poisoning. The severity of the "poisoning" depends on the type and amount of the chemical you are exposed to.

Toxic substances: for platinum catalyst, catalyst toxicants mainly include S, Se, Te, As, Sb, Bi, Zn compounds, halides, etc. Common toxic substances for forming platinum silica gel include putty, clay, putty, solder, photosensitive resin, 3D printing (occasionally), etc. The following are common substances that are likely to cause platinum catalyst poisoning.

1. Amines and amino compounds: Neutralizing amine, ethanolamine, N - methyl diethanolamine, triethanolamine, N - dimethyl ethanolamine, n-butyl amine, diethylamine, triethylamine, tetramethylene ethylenediamine (butyl diamine), cyclohexylamine, melamine, dimethyl formamide, nitriles, cyanate ester, oxime, nitroso compound, hydrazine compounds, azo compound, adiponitrile, methyl ethyl, nitroso, chelation, Ethylenediamine tetraacetic acid (EDTA), ammonia triacetic acid

2, containing sulfur components: dimethylbis, ethylthiohydroxyl acid, allyl thiourea, etc.

3, containing tin components: fatty acid tin salt, organic tin curing agent.

4, phosphorus composition: triphenylphosphonate, phosphite, triethyl phosphite.

5, containing arsenic, antimony, selenium, tellurium composition: triphenylarsine, triphenyl symmetric diphenyl ethylene, chlorobenzene carboxymethyl selenium.

6, residual solvent or monomer: ethanol, methanol, ethyl acetate, vinyl acetate.

7, the bottom coating material: polyethylene acetate or acrylic latex as adhesive clay coating glue, coating glue containing calcium carbonate, natural rubber latex/clay, latex/ethylated starch, styrene/acrylic acid, polyvinyl acetate, polyethylene acetate/acrylic acid.

The above is the in-depth analysis of the platinum catalyst poisoning phenomenon and principle, do you understand?