Polyurethane coating with polyisocyanate crosslinking agent

Polyurethane coating with polyisocyanate crosslinking agent,Introduces the diisocyanate monomer, polyisocyanate, water dispersible polyisocyanate and enclosed the synthesis, properties and application of polyisocyanate.

Polyurethane coating is a kind of coating technology in the 1960 s began to rise. It with excellent performance, in automotive original paint, repair paint, plastic paint, wood paint, industrial paint, fabric, leather coatings, printing ink industry in a wide range of applications.
As countries of volatile organic compounds (VOC) content of attention, in the 1990 s, aqueous polyisocyanate coating technology breakthrough, since then, waterborne two-component polyurethane coatings for a wide range of applications.

Isocyanate monomer were introduced in this paper, polyisocyanate, water dispersible polyisocyanate and closed the main technology and the applications of polyisocyanate.

The types and characteristics of isocyanate monomer. Industrialized production of diisocyanate are aliphatic isocyanate and aromatic isocyanate two kinds big. Aliphatic isocyanate mainly has six methylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexyl methane diisocyanate (H12MDI); Aromatic isocyanates are 2, 4 - and 2, 6 - toluene diisocyanate (TDI) and diphenyl methane - 4, 4 '- and/or - 2, 4' - diisocyanate (MDI). Aliphatic isocyanate yellowing resistance; Aromatic isocyanates in light tend to yellowing.

Isocyanate is the floorboard of all sorts of isocyanic acid ester. If the number of classification with - NCO groups, including single isocyanate R - N = C = O and diisocyanate O = C = N - R - N = C = O and more isocyanate, etc.




Chinese name: Diethyl toluene diamine(DETDA)

Diethyltoluenediamine packing： net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).


Single isocyanate is one of the important intermediates in organic synthesis, can be made into a series of carbamate insecticides, fungicides, herbicides, and also to improve waterproof plastic, fabric, leather, etc. More than two functional groups and isocyanate can be used in the synthesis of a series of excellent performance of polyurethane foam plastic, rubber, elastic fiber, paint, adhesives, synthetic leather, artificial wood, etc.

Currently, the largest output is the most widely used are: Toluene Diisocyanate (Toluene Diisocyanate, TDI); Diphenyl methane Diisocyanate (Methylenediphenyl Diisocyanate, MDI).

Polyisocyanate, is composed of aliphatic and aromatic diisocyanate monomer addition. Will diisocyanate addition polymerization as the cause of polyisocyanate, in addition to occupational health problems, and can improve the function of polyisocyanate after polymerization degree, after polymerization, polyisocyanate functionality is greater than 2, and the reactant (such as alcohol and amine) reaction can be obtained after the three-dimensional mesh crosslinking structure, the crosslinking density of the paint film is high, the paint film with high resistance and patience. In addition, the features of isocyanate itself still exist in the polymer, such as aliphatic polymer has better than aromatic polymers yellowing resistance; And aromatic polyisocyanate reaction film is hard.

Enclosed polyisocyanate, polyisocyanate NCO group and stable polymer sealants reaction can produce under normal temperature, referred to as enclosed polyisocyanate. Enclosed polyisocyanate with polyol resins, room temperature stability of the coatings can be obtained. This kind of coating under the condition of baking, sealants disintegrate under high temperature, release the NCO groups, with polyol resin component crosslinking reaction.

Enclosed isocyanate's advantage is more easy to operate, and is not sensitive to air humidity, can make have enough storage stability of one-component polyurethane coating. The advantages of easy operation, however, is also the limitations, namely the enclosed isocyanate is used only for high temperature baking system. Industrial products mainly include: butyl ketone oxime, dimethyl pyrazole (DMP), malonic ester and diisopropylamine, diisopropylamine/malonic ester, diisopropylamine/triazole, epsilon - caprolactam, cyclopentanone - 2 - carboxyl methyl ester (CPME), nonylphenol and so on.

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Diethyl toluene diamine(DETDA)  http://www.yaruichem.com