Diisocyanate (DDI) is a unique aliphatic diisocyanate with 36 carbon atom dimer fatty acid backbone. The structure gives DDI better flexibility and adhesion than other aliphatic isocyanates. DDI has properties of low toxicity, no yellowing, dissolve in most organic solvents, low water sensitive and low viscosity. DDI is a kind of two functionality Isocyanate, it can work with two or more active hydrogen compounds to make polymer. DDI can be used in solid rocket propellant, fabric finishing, paper, leather and fabric repellent, wood preservative treatment, electrical potting and preparation of special properties of polyurethane (urea) elastomers, adhesive and sealant, etc.

In Fabric industry, DDI shows an excellent application prospect in the water-repellent and softening properties to fabrics. It is less sensitive to water than aromatic isocyanates and can be used to prepare stable aqueous emulsions.

The use of 0.125%DDI gives the fabric a durable softness; Fabrics treated with nondurable cationic softeners have similar flexibility after 26 washes. Fabric water repellent using 1%DDI has the same or better water repellent effect as fat pyridine water repellent (AATCC test).

DDI can improve the effect of water-repellent and oil-repellent for fluorinated fabrics. When used in combination, DDI can significantly improve the water-repellent and oil-repellent properties of fabrics.

Both laboratory and field evaluations have shown that DDI has better resistance to washing and dry cleaning than fluoride or fabric additives such as antistatic agents.

DDI, prepared from dimer fatty acids, is a typical green, bio-renewable isocyanate variety. Compared with universal isocyanate TDI, MDI, HDI and IPDI, DDI is non-toxic and non-stimulating. With the popularity of dimeric acid raw materials in China and people’s increasing attention to low carbon environmental protection economy and sustainable development, the importance of using bio-renewable raw materials to prepare DDI has gradually emerged, which has important practical significance for promoting the development of polyurethane industry.