A natural contender
Recent legislative changes in many countries – and especially across many states in the USA – now allow for the cultivation of hemp crops, especially those that are low in THC.
THC is the psychoactive constituent of cannabis, or marijuana, which is extracted from the hemp plant and has resulted in its widespread use as a recreational drug and its subsequent illegality in most countries for at least half a century.
The prime reason for this about-turn by many governments – 29 US states plus the District of Columbia have now made marijuana available for medical and in some states, recreational purposes, for example – is that the latest research suggests that it may be of benefit in the treatment of a range of medical conditions, including chronic pain, multiple sclerosis, depression, anxiety and epilepsy.
In June 2018, the US Food and Drug Administration (FDA) –while not yet deeming marijuana safe or effective in the treatment of any medical condition – approved cannabidiol, a substance that is present in marijuana, as a treatment for some types of epilepsy.
For cancer sufferers also, evidence suggests that oral cannabinoids are effective against the nausea and vomiting caused by chemotherapy, and some small studies have found that smoked marijuana may also help to alleviate these symptoms.
In the USA especially, this has led to something of a new Gold Rush as companies and investors scramble to take a share of an exploding new market, yet the hemp plant’s shivs, seeds, and especially its fibres, have many other uses. It’s no accident that the plant was cultivated throughout the world and history for use as a food, fuel source, nutritional supplements, body care products and also as the source of paper, building materials, medicines and textiles, before it fell out of favour.
Back in 1938, deeming it the ‘wonder plant’, Popular Mechanics reported that around 30,000 products could be made from the fibres of the hemp plant alone.
Hemp, along with other bast fibres such as flax and kenaf, can certainly be turned into a range of valuable nonwoven products, such as automotive composite reinforcements. Each Mercedes C-Class, for example, is said to contain some 20kg of the fibre in its components.
Before such applications, however, hemp fibres need to be cleaned and prepared by a process called decortication.
Hemp cleaning and decortication technology is a specialisation of Tatham, based in Bradford, UK, which will exhibit at the forthcoming INDEX™20 nonwovens exhibition, which takes place at Palexpo in Switzerland, from March 31st to April 3rd next year.
After growing and harvesting, a hemp crop first undergoes the retting process, most commonly by being submerged in water to let the action of micro-organisms and moisture on the plants dissolve or rot away most of the cellular tissues and pectins surrounding the bast-fibre bundles and separate the fibres from the stems.
The next step towards any high-value hemp fibre product, Tatham explains, is decortication, which removes the tough woody interior (the hurd material), from the softer, fibrous exterior of the stalk.
The hemp fibre decorticating and cleaning unit manufactured by Tatham can process some 4,000 kilos per hour of the fully-retted hemp and complete turnkey units, including equipment for the processing of the shiv and dust bi-products for onward use in briquettes, animal bedding and construction products, can be supplied by the company.
Tatham is also one of a number of INDEX™20 exhibitors that can then supply the nonwoven technology for the production of hemp needled or airlaid mats and felts for automotive and home textile applications, as well as thermobonded products for insulation.
Other specialists in this field include Advance Nonwoven of Denmark, which is making its INDEX™ debut at the 2020 show.
This company’s patented CAFT web forming system – a fusion of carding and airlaying technologies – can handle both very short and very long fibres, mixing them and forming a homogenous mat, while using more air and fewer bicomponent fibres for bonding it together than competing technologies.
CAFT offers the possibility of processing a wide range of natural fibres – hemp and flax, but also pineapple, peat moss and linseed, as well as recycled paper, textiles, glass and carpets – and can make products ranging from thin tissue-like textures to lofty structures and from low to high-density constructions.
Also from Denmark is Campen Machinery, which has introduced a new type of airlaid forming head and hammer mill system designed for robust forming processes.
Bicomponents and PP/PET/viscose blends, as well as recycled fibres from textiles, cardboard boxes, newspapers, wood pulp, natural fibres, glass or even stone-based fibres such as basalt can all be processed with the Campen system.
Natural and recycled fibres from waste are also the speciality of a number of Italian machinery producers, including Bematic and Texnology, who work together on complete carding and needlepunch lines, distinguished by vivid red panels and transparent sections, and Dell’Orco and Villani, which has installed over 300 lines worldwide for textile waste recycling, based on fine opening and blending lines for nonwovens, along with waste tearing machines.
Still in the field of natural and recycled fibre processing, as well as brightly painted machines, this time a pure yellow, Laroche has introduced its new Flexiloft 2600 airlaid machine. Not only can this machine process all short and long natural and recycled fibres, as well as special fibres such as glass, silica, carbon and aramid, it can also produce nonwovens in blends with non-fibrous components such as plastic, foam and wood chips.
INDEX™20 will cover all aspects of the nonwovens industry, from the fibres and processing technology through to fully finished products.