At present, most of the waste silk and its textiles are treated by incineration and burial, which causes a great waste of resources. Exploring new technologies and processes for the recycling of waste silk, improving the recovery rate of waste silk, and realizing the recycling and reuse of waste silk will help promote the sustainable development of the industry.

Regenerated silk fibroin (RSF) fibers with different properties can be obtained by modifying silk fibroin by adding functional materials to the silk fibroin solution, using different spinning processes or post-treatment methods, etc. Thanks to the excellent biocompatibility and easy modification of RSF, it has been applied in nonwovens, biomedicine, electronic sensing, energy storage and other fields.

In terms of non-woven fabrics, RSF contains 18 kinds of amino acids and various trace elements, which has a strong affinity with human skin and is easily absorbed by human skin. The birth of modern biochemical technology and nanotechnology has further improved the skin's absorption of silk fibroin and other trace elements.

The RSF spunlace nonwoven fabric and facial mask fabric woven by RSF fibers through the spunlace process can increase the water content of the stratum corneum of the skin, promote the synthesis of collagen, enhance the tension and elasticity of the skin, promote the decomposition of pigments, and even out the skin tone. Frequent use of silk fibroin beauty and skin care products can make the skin fair, moist, shiny, and elastic, and can significantly improve the skin problems of sallowness, dullness, dry lines, and sagging.

Regenerated silk fibroin (RSF) fiber is made by extracting silk fibroin from silkworm cocoons and waste silk, and then it is made through main processes such as hydrolysis, filtration and purification, filtrate pH test adjustment, concentration, sterilization, and spinning.

Regenerated silk fibroin (RSF) facial mask fabric technical indicators:

① Appearance: light yellow transparent liquid, no peculiar smell, easily soluble in water.

② The biuret reaction is positive, and the ultraviolet absorption spectrum has a strong absorption peak at a wavelength of 200-240nm.

③ The pH value is 6-7.

④ Specific gravity (d 2. o) 1.000~1.050.

⑤ Protein content: >/14%.

⑥ Amino acid: 17 kinds in total, containing more than 87mg per ml.

⑦ Ash content: below 1%.

⑧ The heavy metals mercury, arsenic and lead are below 1ppm respectively.

⑨ The total number of bacteria (number/m1) ≤ 10.

⑩Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were not detected.