Dry wipes or wet wipes usually cause issues with sewage systems due to their failure to disintegrate in water. To counter this problem, Voith Group (Division: Paper) and Truetzschler Nonwovens joined hands to develop flushable wipes. These wipes can be flushed down the toilet because they disintegrate into individual fibres in agitated water.
The wet-laid process for nonwovens is similar to the making of paper. The first step involves suspension of fibres and water to form a slurry, so that single fibres of different types are evenly distributed in the water. The web formed is passed over a wire belt. When water is sucked off, a homogeneous fibre mat is formed. The spunlacing process performed by the AquaJet system on this fibre mat further produces nonwovens that feel like textile.
Unlike a carding process where longer fibres are required, wet-laying can utilise short fibres of 2 mm to up to 15 mm to form the web. In principle, every fibre that is dispersed in water can be wet-laid. Hence, fibres of low cost like wood pulp i.e., cellulose fibres, man-made and mineral fibres, etc., can be used. The WLS (wet-laying/spunlacing) process goes without binders by hydro-entangling the single fibres. Wipes produced through wet-in-wet processes are extremely versatile.
Truetzschler Nonwovens in collaboration with Voith Paper offers the following solutions for manufacturing wet-laid nonwovens:
HydroFormer from Voith Group
Most conventional dry or air-laid sheet forming processes are based on the use of long fibres. This meant that in the past, it was often not possible to use the less expensive and more environmentally compatible pulp fibres for nonwoven production. To close this gap, Voith's HydroFormer acts as a bridge between paper and nonwoven production.
The HydroFormer concept for wet-laid nonwovens builds on Voith's longstanding experience from the paper and pulp industry. Inexpensive and biodegradable, thanks to a very high dilution in suspension, nonwovens produced by the HydroFormer can be produced entirely out of renewable, cost-efficient cellulose feedstock. Apart from the obvious cost savings and environmental benefits, this process offers homogeneous sheet formation and considerable flexibility for multi-ply end products. It also enables the manufacturing of disposable cleaning wipes from 100% biodegradable materials.
Voith Group's HydroFormer has been specifically optimised for the formation of wet-laid nonwovens and, with more than 70 successful installations, has gained worldwide acceptance.
Benefits of the HydroFormer
• Cost effective use of raw materials
• Renewable materials used exclusively
• Considerable minimisation of fibre losses due to re-use
• Simple one step manufacturing of multi-ply products
• Extensive flexibility in raw material use
AquaJet for spunlacing from Truetzschler Nonwovens
After the web is formed in the HydroFormer, it needs to be bonded to add strength and function. In the bonding step, the know-how from Truetzschler is applied. Web bonding is performed with the help of the AquaJet. In this field, Truetzschler Nonwovens can draw on its extensive experience of more than 100 projects running worldwide.
Compared with other web bonding methods, the AquaJet spunlacing process does not use chemical binding agents or bicomponent fibres, but relies only on the momentum of water jets to entangle the fibres with one another. Continuous high-pressure water jets strike the loose nonwoven web, which is moved through on a belt underneath the water bar, while suction fans remove the water used. The bonding increases tensile strength and lends the material the soft feel of a textile. Structures and perforations can also be created, if required.
Benefits of the AquaJet
• Use of environmentally friendly and inexpensive raw materials
• Soft nonwovens
• Natural bonding process using water only
• High savings potential - thanks to optimised pump and vacuum performance
• Integrated system for excellent nonwoven quality
In harmony with the environment
Apart from short fibres being used, the Voith-Truetzschler process avoids the use of chemical binders to bond the web formed. This reduces the raw material cost for making nonwovens. Compared to oil-based materials like PET/PP fibres, cellulose fibres do not burden the environment after use. Wipes produced entirely from these degradable fibres in a customised wet-laid spunlacing process can therefore be conveniently flushed down the toilet.
Both the AquaJet and the HydroFormer have been developed with water conservation in mind. The water from the process is filtered via a shared water cycle with downstream production steps, and then treated and returned to the manufacturing process.
Flushable products must pass a defined test sequence developed by INDA and EDANA, the North American and European nonwovens associations.
About Voith Paper:
Founded in 1867, Voith Paper is a pioneer and a leading partner to the paper industry. Through constant innovation, Voith Paper is optimising the paper manufacturing process, focusing on developing resource-saving products to reduce the use of energy, water, and fibres. Voith is headquartered in Germany and has sales & manufacturing worldwide.
Truetzschler, founded in 1888, is a family-owned German company with global operations that specialises in the manufacture of machines, installations, and accessories for spinning preparation, nonwovens and man-made fibre.