Hexamethylenediamine is force majeure again! Where is the soaring HDI system?

On April 21, BASF stated that the company received a force majeure notice from a raw material supplier. Raw materials such as adiponitrile (ADN), hexamethylenediamine (HMD), and AH-salt will all reduce their supply. Hexamethylenediamine is a strong basic organic substance, an important chemical raw material, and a toxic substance that has physiological effects on the human body. Hexamethylenediamine is mainly used in organic synthesis, the most important downstream of which are PA66 and HDI. Affected by this, the already soaring price of HDI curing agent may further rise.

Since September 2020, HDI curing agent has been rising from a low price of 35,000 yuan/ton. By the end of April 2021, the quotation of HDI trimer bulk orders has exceeded 130,000 yuan/ton. However, at such a high price, it is still a commodity Hard to find. The soaring price of HDI curing agent is closely related to the tight supply of its upstream raw materials hexamethylenediamine and adiponitrile. Since the second half of 2019, plants such as INVISTA USA, INVISTA-Solvay France's adiponitrile, BASF's hexamethylenediamine, and Ascend have experienced force majeure to varying degrees, and the global supply of adiponitrile/hexanediamine has continued to be tight. At the beginning of this year, affected by the extremely cold weather, INVISTA and Ascend successively announced force majeure on hexamethylenediamine, and the global supply of hexamethylenediamine became increasingly tight.

As the most important monomer in aliphatic diisocyanate (ADI), HDI accounts for about 60% of the total demand for ADI. HDI monomer is mainly used in adhesives, accounting for about 10% of HDI demand, but the monomer is volatile and toxic, so it is generally prepared into HDI derivatives and used as a curing agent for polyurethane coatings. HDI curing agent has no isocyanate group directly connected to the carbon atom on the benzene ring, so it is not easy to be oxidized, making the most notable feature of this kind of coating is yellowing resistance and weather resistance. It is the best in the family of polyurethane coatings. According to Tiantian Chemical According to statistics from the Internet, about 70% of the world's HDI is widely used in automobiles, wood, and industrial coatings. At present, HDI-based polyisocyanate mainly includes HDI trimer and HDI biuret on the market. In addition, various companies are constantly working on the research and development of new HDI curing agents, and HDI polyisocyanate products with special properties emerge in endlessly.

HDI trimer--a trimer containing isocyanate heterocyclic structure is obtained by polymerizing HDI monomer in the presence of a catalyst.

The so-called HDI trimer also contains pentamers and heptamers. According to different degrees of polymerization, different products can be prepared. The greater the degree of polymerization of HDI monomers, the higher the functionality of the trimers and the lower the viscosity. higher. At present, the HDI trimer products circulating in the market are mainly 100 solid content and 90 solid content, which are used in automotive coatings, advanced wood coatings, industrial protective coatings and other industries. At the same time, high-performance curing agents that can reduce VOC, such as modified HDI trimers used in waterborne polyurethane coatings, not only improve the solid content and water resistance of the curing agent, but are also more environmentally friendly, and are becoming more and more popular in the market .

HDI biuret--It was successfully produced by German Bayer company in 1958 through the reaction of HDI and water. It is a triisocyanate with a biuret structure. Also, according to the degree of polymerization, it is mainly divided into standard type and low viscosity type. At present, the biuret curing agent circulating in the market mainly contains 75% solids. Through the preparation of different systems, it is widely used in outdoor weather-resistant coatings, automotive refinishing coatings, industrial coatings and wood coatings. In addition, some subdivided products in the HDI curing agent market, such as HDI-TMP adducts, closed HDI and other products, although their applications are not as extensive as biurets and trimers, they also occupy a place in the market: HDI-TMP adduct - It is formed by the catalytic reaction of three molecules of HDI and one molecule of trimethylolpropane, and is mainly used as a curing agent for polyurethane adhesives.

The polyurethane adhesive made of it is widely used because of its low temperature resistance, shear resistance, impact resistance and high bond strength, especially in the industries of adhesives, automobile windshields and wood-based panels. growing at a rate of more than 5%. The synthesis process of HDI-TMP adduct is simple and has great market potential. Blocked polyisocyanate - HDI is blocked with phenol, ε-caprolactam, etc. to form a blocked isocyanate, which can be combined with various oligomer polyols. This type of curing agent can be used to formulate one-component baking coatings for various metal and plastic coatings, such as wire enamels and coil coatings. It is generally mixed with other curing agents, such as melamine curing agent, to reduce costs and improve performance.

HDI-TDI mixed polymer--a certain proportion of HDI and TDI is prepared under the action of a catalyst. It has the characteristics of anti-yellowing and low viscosity. Since the production cost is lower than that of HDI biuret and HDI trimer, it is used to make two-component polyurethane varnish or paint, and has high cost performance.

In addition, with the deepening of HDI research, other HDI curing agents such as HDI uretdione polyisocyanate, bio-based HDI polymers, HDI-HMDI adducts and other HDI derivatives are also being developed and marketed. Polyurethane coatings have now become the mainstream technology in many application fields and have been generally recognized, while high-performance and environmentally friendly HDI curing agents that can reduce organic volatile emissions will be more widely used in the future. Tiantian Chemical Network predicts that the compound growth rate of China's HDI industry is expected to remain at about 10% in the future, and there is huge room for future development.