What is Milk Fiber Yarn and How is it Produced?

Updated: 6 days ago

A milk protein called casein is used to make innovative fibers that resemble wool. New technologies have been constantly being researched and incorporated by the textile industry for a long time. These researches result in innovative textiles such as fabrics made from milk.

What is Milk (Casein) Fiber?

Waste milk unfit for human consumption is used to produce innovative fibers called milk fiber or casein fiber. Milk fiber fabric is a blend of casein protein derived from milk and acrylonitrile, the same chemical used to make acrylic. Or it is made from pure casein protein. Waste milk still contains valuable ingredients and offers great potential for technical purposes as well.

Milk-blend cotton yarn was first created in Italy and the USA in the 1930s and was called milk casein. It was made to compete with wool, but production stopped during WWII. Initially, formaldehyde and large amounts of water were used in the manufacturing process. However, this resulted in an unprofitable production method.

In the 1930s, Italy was a pioneer in making Lanital, a wool-like textile made from milk. Production started with the separation of milk and cream. The cream is used to produce butter, and skim milk is then coagulated to remove casein.

By mixing acid with milk, chemists can extract casein protein, which looks like cheese in appearance. Casein is dissolved in a liquid resembling molasses and passed through nozzles. It is put in a chemical bath. The resulting milk fiber fabric is hardly distinguishable from wool.

Historically, milk fiber yarn was mixed with various substances to give them a cotton-like texture and tension. But these days it's mostly made with a mix of casein protein and acrylonitrile. Therefore, it is not a true organic or natural fabric as it is semi-synthetic.

Traditional Production Process of Dairy Fiber Fabric

Converting milk waste into fabric requires a very technical process. To make milky fabric yarn, the casein protein must be extracted. Casein is obtained when milk is acidified. Different sub-processes are used and these are the two main production processes. Both will have the first step of obtaining the waste milk.

  • The milk is skimmed to extract the fat and then dehydrated and fermented. At this point, it is similar in appearance to a milk-based protein powder.

  • The casein fiber is extracted - the casein is coagulated, washed and dried, and then ground into a fine powder. The milk powder is dissolved and purified to remove non-casein substances.

  • Casein is then dissolved in caustic soda solution and left to mature until it reaches a certain viscosity. It is then filtered and vented.

  • The spinning solution is then wet spun by extruding from the spray nozzles into a coagulation bath.

  • The coagulation bath consists of 2 parts sulfuric acid, 5 parts formaldehyde, 20 parts glucose, and 100 parts water. The filaments coagulate in a similar fashion to viscous filaments.

  • The fiber must then go through a chemical treatment to harden it. Formaldehyde forms the basis of most curing techniques. As the filaments exit the coagulation bath, they are aggregated and immersed in formaldehyde solution. At this stage, the filaments are subjected to the drawing process.

  • The next step is to wash and dry, and then it is mechanically crimped before being cut into staple fibers. Casein fiber is produced almost entirely as staples, tows, or balls.

Alternative Production Method

This is another process that is similar but with minor differences and involves fewer steps and chemicals:

  • The milk is fermented, then de-fatted and dehydrated.

  • The casein fiber is extracted and the milk powder is dissolved and purified. Non-casein substances are removed.

  • Powdered casein is dipped in alkali and passed through nozzles to make a solution.

  • The solution is dipped in sulfuric acid to remove the alkali.

  • The fibers are then stretched and spun into milk fiber yarn.

  • It is then tanned with aluminum salts and formaldehyde into a usable textile for food-made clothing.

  • Modern Technique

  • The production process has changed due to the toxicity of formaldehyde and the harmful effects of other chemicals.

  • The modern method of producing casein fiber goes through a process called graft copolymerization. This is the chemical inoculation of pure casein with acrylonitrile. It doesn't require the use of formaldehyde, but acrylonitrile is also toxic and carcinogenic, so it's still a chemical we want to avoid.

Milk fiber fabric made in China is normally made with acrylonitrile, so it still cannot be classified as eco-friendly or sustainable.

A new process that is more environmentally friendly and does not use formaldehyde or any other chemicals has been developed by a German company called QMilch GmbH.

What Does QMilk Company Do?

QMilk was started by Anke Domaske, a microbiologist, after searching for clothing that had not been treated with chemicals. Milk proteins caught his attention. But since the original textile process used in the 1930s was complex and involved a variety of chemicals, he established QMilk as a classic kitchen startup.

QMilch GmbH was founded in April 2011 and there is currently a group of companies involved in the development and production of biopolymers. They are based on milk proteins and other natural and renewable raw materials.

The fabric called QMilk is made from milk fiber yarn using waste milk that is not suitable for human consumption. Milk was normally obtained from a dairy. QMilk has developed a process that is 100% natural and uses renewable resources. No plasticizers, solvents, or chemical crosslinkers are used. The fiber can be composted at home and will decompose and biodegrade in the environment within a few months.

Environmentally friendly QMilk Procedure

QMILK is a patented, specially designed manufacturing process. Part of the process includes:

  • heating casein powder to 80°C in a meat grinder,

  • Adding natural ingredients like zinc and beeswax.

  • The fibers come out in strips and are then spun into yarn.

As it is a patented process, no further details are available on the individual steps for making milk cotton yarn. Thus, no formaldehyde is used and certain cost efficiency and minimum CO2 emissions are achieved. It is 100% natural, soft and smooth as silk. It is skin-friendly and meets the requirements of innovative material developments.

QMilch received the Green Tec Award in 2015. QMilk fiber has also passed the OEKO TEX standard 100 green certification for international ecological textiles. It answers the call for sustainable natural fibers and opens up exciting new possibilities for innovative textiles.

You need about a hundred pounds of powdered milk to make three pounds of milk fiber. The fibers are white, fluffy, and emit a pleasant smell. Innovative fibers can be dyed using acid, reactive or cationic dyes.

QMilch Fiber Applications

QMILK is a protein fiber and is ideal for direct skin contact as it feels like silk on the skin. QMilk fibers do not contain the following harmful substances usually found in textiles and products:

  • isocyanate and halogens.

  • solvents

  • dangerous plasticizers

  • silver, zinc oxide, and triclosan

So what is the milk fiber material used for? QMilk fibers have fashion and technical applications in hygiene and medicine.

1. Fashion applications of QMilch Fibers

QMilk can be combined with any type of wool, but can also be spun with cotton, cellulose, or other natural fibers. It can be used as an alternative to cotton or silk. But it can be combined with silk and cotton to create a smoother texture. Milk cotton yarn is perfect for underwear because of the healthy and bacteriostatic nature of the milk fiber.

Besides being good for underwear, it is also used for socks, home textiles, and garments made from wool.