Issue 05/2015

Fibers & Textiles
QMilk fibres close
to market launch
QMILK fibre is a 100 % natural and renewable textile fibre made of nonmarketable
milk and produced using an eco-friendly process. The
textile fibre is multifunctional, antibacterial, compostable and flame
retardant. Qmilk fibre has a natural, silk-like quality and very good color
absorbency.
Founded in 2011, Qmilch GmbH (Hanover, Germany) now boasts 20
employees who work in a two-shift system; the company operates a
production line with an annual capacity of 1,000 tonnes. Now getting ready to
enter the market with the first fibres the initial focus will be in the technical
sector, followed by the clothing and home textile industry.
As Qmilk fibres are made from casein, they are characterized by their
protein composition. Casein is similar to sheep wool in its structure.
However, unlike in wool keratin, there are no sulfate bridges. Just like wool,
Qmilk fibres have a better thermal insulation capacity than cellulose fibres.
“It is quite important to have knowledge of the general chemical properties
and possibilities for implementation to understand the mode of reaction and
behavior of Qmilk fibres,” says Anke Domaske, founder and CEO of Qmilch.
Casein is a globular protein and consists — in addition to aminodicarboxylic
acids — of diaminocarboxylic acids and cystine. Hence casein exhibits (in
analogy to keratin) amphoteric properties and can bind acids and bases to
form salts.
Even if Qmilk fibres are made from regenerated proteins, they are not
regenerated protein fibres, simply because the proteins were not present in
the form of fibres and can therefore not be regenerated from fibres. In fact,
the proteins are formed into fibres only after they have been dissolved, in the
course of which their initial morphology is destroyed.
Qmilk is not a thermoplastic, but belongs structurally to the thermosets.
This means no fixed melting point of the material can be detected. Therefore,
it shows a high fire protection classification (B1-B2, DIN 4102-1 and DIN
75200) and is not electrostatic. The molecular weights are found in a range
from several thousand to several million units. No spin finishing needs to be
applied during manufacturing.
In comparison to cellulose fibres, Qmilk fibres are highly alkali sensitive,
yet with a greater acid resistance. The fibre can therefore be readily stained
with wool dyes in the acidic range. Qmilk fibres are easily dyeable in the
spinning process, as well as yarn and piece dyed. The fibres can be used in
textile fibre blends, as well as in 100 % Qmilk textiles. The colour crystals
of the milk protein casein provide exceptional colour brilliance. Spun-dyed
processes in particular offer high colour strengths, because the pigment is
incorporated directly into the polymer matrix.
Qmilk uses a side stream of the food industry. About 2 million tonnes of
milk are annually discarded in Germany alone (worldwide about 100 million
tonnes) because they do not meet the legal requirements as a food. The
CO 2
emitted during the production of this non-food milk is bound, as the
milk is further processed into a high quality raw material. The feedstock is
abundant: now that the European milk quota legislation (1984 until March
2015) has been abolished, the production of milk – including all unavoidable
byproducts or waste streams – continues to rise.
Qmilk can be produced from contaminated milk products, process water
in the dairy industry or expired milk. MT
www.qmilk.eu
Fibres exiting the dies
Staple fibres
The fibres are getting texturised
bioplastics MAGAZINE [05/15] Vol. 10 13