Crosslinking of collagen

Abstract It has been shown that the introduction of a few stable crosslinks into the skin protein can greatly increase the resistance of the leather to deterioration by moist heat and perspiration. A method based on stress‐strain measurements has been developed for the determination of the number of crosslinks introduced into collagen, and a study made of the crosslinking potentialities of a number of bifunctional and polyfunctional compounds. Aldehydes appear to be most promising, cyanuric chloride and its derivatives also offer possibilities, while di‐isocyanates are relatively inefficient due mainly to their low solubility in and sensitivity to water. Of the aldehydes, glutaraldehyde and acrolein were the most efficient both with respect to the number of crosslinks introduced and their stability. Leathers tanned with glutaraldehyde show good resistance in moist heat and perspiration tests and pretannage or retannage of chrome leather with this aldehyde greatly improves its resistance.