Contribute to the sustainable development of natural materials and create next-generation fibers

The growing international interest in global environmental issues in recent years has had a major impact on the world of fashion and clothing. There are many issues in securing raw materials, resource consumption during manufacturing, mass consumption, environmental load due to disposal. With the cosideration for the future of the industry, each country is making various efforts.

Toyoboshi, since its founding in 1879, has been conducting research on the spinning and development of natural fibers. Along with an effort to to protect rare natural resources such as cashmere, we have been working hard to improve the quality of our products. On the other hand, these natural materials are finite, and chemical fibers have played a major role as alternatives in the clothing industry, but synthetic fibers such as polyester are materials that have many problems in recycling and disposal. There is a strong need to change to something that does not place a burden on the environment. Toyoboshi Co., Ltd. is promoting collaboration and partner relationships with companies with various advanced technologies, and develops textile products that have both high functionality and environmental friendliness.

Functionality and comfort

"INFIL" was born from such a movement, which is a hybrid fiber with PLA (Polylactic acid)[1]and silk.

PLA (Polylactic Acid))Is a biomass plastic made from plants such as corn, combined with silk, we made a layered non-woven fabric. The fiver achieves antibacterial properties, comfort, and biodegradability by making the best use of the characteristics of each material. INFIL works as an inner sheet for masks all season.


  1. Antibacterial

It has an excellent antibacterial effect thanks to PLA (Polylactic Acid) as a weak acidic fiber and antibacterial fiber of the 2nd layer  [2] Strong antibacterial effect against Staphylococcus aureus and pneumonia bacillus[3]is recognized.

  1. Comfort

Silk has a high affinity with the skin and is gentle on the bare skin, less likely to cause rashes or dermatitis. The cool contact feeling of silk and PLA moisture release function induces heat of vaporization and makes the skin feel cool in summer. We also focused on the three-dimensionality of the fibers. Taking advantage of the characteristics of (hard fiber that produces elasticity and elasticity), with Spunlace manufacturing method [4]utilizing the carding characteristics (fiber direction) of the layers, genarated an appropriate space in the mask. It does not stick to the skin and is comfortable to wear for a long time.

  1. Biodegradable fiber (Biodegradable)

All four layers are naturally derived biodegradable fibers (biodigradable), mainly silk and sorghum.PLA after use  can be decomposed into water and carbon oxide by microorganisms in a certain environment. Even if it burns as garbage, is recognized as carbon neutral without increasing Carbon dioxidite

4-layer structure




Material features

Composition ratio


1st layer(Skin side)




Span lace

Bacteriostatic, beauty effect, UV protection, moisturizing




2nd layer

Antibacterial fiber


Antibacterial and moisturizing


3rd layer

& HardPLA



Plant-derived, weakly acidic, antibacterial, deodorant


4th layer(outside)


Span bond



[1] PLA polylactic acid --BioworksCompany


[2] Kaneka Regenerated Collagen Fiber LUXAIRE®

[3] Antibacterial performance

Staphylococcus aureus 4.9   Pneumonia bacillus 6.1
The recommended standard level is2.2that's all,2that's all3Less than = effect is recognized.3that's all=A strong effect is recognized.

[4] A manufacturing method in which short fibers are used as raw materials and the fibers are entwined with a high-pressure water stream. It is said that the non-woven fabric manufacturing method is similar to weaving and knitting.