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Overview of chain extenders for polyurethane (TPU):


Polyurethane (referred to as TPU) is a polymer made of polyisocyanate and polyether polyol or polyester polyol or / or small molecular polyol, polyamine or water and other polyurethane (TPU) chain extender or crosslinker and other raw materials. The chain extender of polyurethane (TPU) is used to synthesize polyurethane. By changing the type and composition of raw materials, the shape and properties of products can be changed greatly, and the final products from soft to hard can be obtained.


Polyurethane is called polyurethane (English Name: polyurethane), which is a general designation of macromolecular compounds containing repeated carbamate groups (nhcoo) on the main chain. It is formed by the addition of organic diisocyanate or polyisocyanate and dihydroxy or polyhydroxy compounds. In addition to carbamates, polyurethane macromolecules can also contain ether, ester, urea, biuret, urea formate and other groups.


Polyurethanes (TPU) are extenders for the synthesis of polyurethanes. Their products are soft, semi hard and rigid foam plastics, elastomers, paints, adhesives, sealants, synthetic leather coated resins, elastic fibers, etc., which are widely used in automobile manufacturing, fridge manufacturing, transportation, civil engineering, footwear, synthetic leather, fabrics, electrical and mechanical, petrochemical, mining machinery, aviation, Medical treatment, agriculture and many other fields. Polyurethane is a new organic polymer material, known as the "fifth largest plastic", which is widely used in many fields of national economy due to its excellent performance. At present, there are about 80 kinds of polyurethane products in China. Among them, there are more than 60 kinds of elastomers, more than 10 kinds of foam plastics, and polyurethane products are of high strength, high compression resistance, good tear resistance and wear resistance. The application area of products is light industry, chemical industry, electronics, textile, medical treatment, construction, building materials, automobile, national defense, aerospace and aviation. The synthesis of polyurethane by chain extender is a kind of high molecular compound which is composed of two or more isocyanates and two or more hydroxyl compounds.


Overview of polyurethane catalyst:


Polyurethane catalyst is a kind of assistant to accelerate polyurethane reaction.


Chinese Name: polyurethane catalyst

Foreign name: Pu catalyst

Including: dy-dmaee / dy-12 / dy-8 / DY-5, etc

Mainly divided into: organic amines, organic metal salts, etc

Commonly used: only 20 kinds, etc


Classification of polyurethane catalysts


The catalysts commonly used in the synthesis of polyurethane and its raw materials are mainly tertiary amine catalysts and organometallic compounds. There are many kinds of tertiary amines and organometallic compounds. Considering various factors, only 20 kinds of them are most commonly used in polyurethane production.


amine catalyst


Amine catalysts are commonly used in the production of polyurethane foam, which are mainly divided into the following categories:


Aliphatic amine catalysts include n, n-dimethylcyclohexylamine, bis (2-dimethylaminoethyl) ether, N, n ', n' - tetramethylalkylenediamine, triethylamine, N, n-dimethylbenzylamine, etc.


Alicyclic amine catalysts include solid amine, n-ethylmorpholine, N-Methylmorpholine, N, n '- diethylpiperazine, etc.


The catalysts for alcohols are triethanolamine, DMEA, etc.


Aromatic amines include pyridine, N, n '- dimethylpyridine, etc.


Organometallic catalyst


Among the polyurethane elastomers, adhesives, coatings, sealants, waterproof coatings, paving materials and other formulations, the most commonly used organic metal catalysts, such as dibutyltin dilaurate (dy-12), are very effective in promoting the reaction of isocyanate group and hydroxyl group, but they also accelerate the reaction of water and isocyanate in the formula with water, which is doubted to be in the plastic raceway Special catalysts such as organic lead can be used.


Organometallic compounds include carboxylates, metal alkyl compounds and so on. The main metal elements in organometallic compounds are tin, potassium, lead, mercury, zinc and so on.


Common varieties:

DY-1 (dimethylaminoethyl ether), DY-5 (pentamethyldiethylenetriamine), dy-8 (dimethylcyclohexylamine), dy-12 (dibutyltin dilaurate), dy-20 (organic bismuth), dy-41 (triazine trimerization catalyst), etc.


Polyurethane catalyst storage:


Dry and sealed storage