Aldehyde and similar-to-aldehyde tanning agents were used in oil tanning and smoke tanning in ancient times. The aldehyde group reacts with the protein amino group in electrophilic form to obtain the preservation stability and practical function of fur and leather. The results showed that aldehyde-tanned leather can promote the hydrothermal stability of skin collagen and has better water and sweat resistance properties than chrome tanning. However, aldehyde tanning agents always lack sufficient coulombic attraction to penetrate well into skin collagen, and some aldehydes have biotoxicity and color, are not easy to dissolve and have high manufacturing costs. In this paper, the structure and application characteristics of some aldehydes are reviewed. According to prior theory and practice, the development of new aldehyde tanning agents and additives has good prospects and significance for providing substitutes for chrome tanning agents.

High-end leather packaging material safe, environmentally friendly, and has a good market prospect. It is an interesting technology to solve the intrinsic functionalization of skin collagen packaging materials. Nano-Hydroxyapatite (HA) precursors solution with a specific 1.67 calcium to phosphorus ratio (Ca/P) were infiltrated into the three-dimensional collagen network matrix (3DCM) in situ growth based on goat skin pretreated with glutaraldehyde and the HAG-3DCM was obtained. After compression, a transparent film HAG-3DCM-was formed. Structural and functional characterization showed that the HAG-3DCM-CM film has good comprehensive performance, such as the tensile strength increased to 67 mPa from 28 mPa, the bending resistance increased from 5 cycles to 50 cycles and the swelling degree from 55% to 12%. HA disperses and fixes the three-dimensional collagen network matrix (3DCM) fibers, improves its stability against humidity and heat, and the thermal conductivity changed from 0.72 W/(K•m) to 0.65 W/(K•m). HAG-3DCM has a relatively high limiting oxygen index of 26.5%. This study demonstrates a new approach for preparing animal skin packaging materials with new application value.