Known as ‘vegetable cashmere’, soybean protein fiber (or SPF for short) is the textile every fashion sustainability enthusiast should know about. Super soft and naturally cream-colored, this sustainable fiber has yet to hit the mainstream market – but that doesn’t mean it doesn’t deserve a bit of spotlight! 


It’s hard to tell who the originator of soy protein fiber is. Some insist Henry Ford invented SPF in 1937 and called it ‘soy wool’. There is even a photograph of him wearing an SPF suit or his 78th birthday. Others say Japanese scientists began looking into SPF in 1940. This also makes sense since the Japanese produced 450,000 kg of SPF before World War Two. Finally, Robert Boyer introduced SPF in 1940 and patented it in 1947. The ‘new’ SPF was invented in 1998 and is being used in different textile products today. 

How Is It Made? 

The new bioengineering technology is essential in making SPF. Here’s the simplified process of making SPF

  1. Protein is distilled and refined from soybean cake 
  2. The enzyme and auxiliary agent are added to change the “space structure of spherical protein” 
  3. Fiber is made with a wet-spinning process 
  4. Curling thermoforming 
  5. Fiber is cut into short stapes

While there’s quite a lot of science involved in producing SPF, the process does not create pollutants and any waste can be used as fertilizer

Why It’s So Great

Don’t let the science words throw you off, SPF is still awesome. Because it’s made from plant matter, it’s biodegradable. It’s also breathable while still being warm and is quite water absorbent. Water absorbency is quite important for textiles because it keeps our skin dry in case we run through the rain or spill a drink. Lyocell was designed with water absorbency in mind, so the fact that SPF is also absorbent is fantastic! The soft SPF fibers also offer more resistance to ultraviolet rays than cotton, so your delicate skin can stay protected from the harmful UV rays all year round. 

All around, the upkeep of SPF is incredibly simple. Unlike some more fussy fabrics, cleaning SPF is rather energy efficient since it can be easily washed in cold water and dries quite quickly. Because of its anti-crease characteristics, ironing isn’t as much of a concern with SPF. 

Debunking myth that soy is bad for the environment

The reality is, soy is not bad for the environment, the animal agriculture’s insatiable need for land and resources is. The animal agriculture industry has given soy a bad rep with all of its rainforest deforestation and other destructive practices. 

From 2017 to 2019, 77% of soy grown was used to feed livestock, the biggest being poultry. Only 19.2% of soy grown is actually for human consumption, with soybean oil making up most of that number. Only 3.8% of soy grown is for industry use, which includes products like SPF. At the end of the day, growing soy to wear is not the issue – growing it to feed to animals that produce far less food than the amount of food they consume is!

In Conclusion…

Keep your eyes out for Soybean Protein Fiber! Some niche indie clothing companies have already begun to sell it but it’s not super popular. It’s an innovative textile that highlights how unsustainable polyester and other plastic-based textiles are. From hemp, to linen, to cotton, biodegradable textiles are essential in a world where more clothing ends up in a landfill. 

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