Polyurethane leather resin:

1. Isocyanates: 

diphenylmethane diisocyanate (4,4'-MDI), toluene diisocyanate (TDI), HMDI, IPDI, HDI,

2. Polyols: 

polyester polyol, polytetrahydrofuran glycol (PTMEG), polyester polyether copolyglycol.

3. Cross-linking agents and catalysts

  The cross-linking agent is generally a solution of low molecular weight polyisocyanate, with an average number of functional groups of about 3. Commonly used cross-linking agents are similar to those used in adhesives and coatings, with a solid content of 75% and an NCO content of 12% to 13%.

4. Solvent

Dimethylformamide (DMF), toluene (TOL), ethyl ketone (MEK), ethyl acetate (EtAc), etc., N-methylpyrrolidone (NMP)

5. Surfactant

Dioctyl maleate sodium sulfonate (OT-70), Span series (Span-60, Span-80), tetradecanol, cetyl alcohol, stearyl alcohol and eicosyl alcohol. In addition, silicone surfactants are also commonly used.

6. Colorants

Carbon black, titanium dioxide, polymer yellow, iron oxide red, metal complex dye, dispersion system composed of carbon black, carrier and additive, color masterbatch

7. Filling

Wood flour (350-400 mesh microcrystalline cellulose), light calcium carbonate, calcium sulfate, wollastonite, silica, etc.

8. Leveling agent

Diphenyl polysiloxane, methylphenyl polysiloxane, organic modified siloxane, fluorinated siloxane, etc.

9. Defoaming agent

Silicone oil-polyvinyl alcohol composite silicone defoamer, polyether defoamer and polydimethylsiloxane eliminate bubbles in the slurry and avoid being brought to the leather surface to form pinholes.

10. Use hand feel agent, brightener, and matting agent on the surface.

Wax feel and slip agents. Wax feel agents are usually wax emulsions or organic solvent dispersions made from natural or synthetic waxes. Slip agents are usually silicone-containing emulsions or high-melting wax emulsions.