With complete pilot-scale prototyping facilities already helping customers across multiple sectors to develop novel products and enhance and improve existing lines, NIRI – Nonwovens Innovation – continue their investment strategy with major new upgrades to spray bonding capabilities.
 
Bespoke-engineered for NIRI’s clients’ needs, the new equipment is specifically designed for the application of binders to both high and low loft fabrics and features a dedicated spraying rig for pilot-scale binder applications and continuous binder application.  With 87% of Europeans worried about the environmental impact of plastic, and 74% worried about the impact on their health, the EU’s Single Use Plastic Directive (SUPD) continues to have a significant impact on nonwovens, particularly in sectors such as wipes, sanitary and feminine hygiene products; general medical supplies and devices; packaging, and the food and beverage industry.  As companies replace single-use plastic products with plastic-free versions, bio-based binder application can help bridge any performance gaps.  This technique can reduce linting and lead to better quality products, with improved softness and comfort; greater structural integrity and processability; improved aesthetic appearance; and better surface functionality.  Products developed using bio-based binder technology can be completely biodegradable and, potentially, 100% compostable. 
 
While the environmental and sustainability benefits are clear – helping companies comply with current and future regulatory demands – on a commercial level the technology can offer enhanced performance and possible cost reductions given the improved functionality.  NIRI’s facilities are designed such that the pilot scale application of binder by spraying allows for more controlled impregnation which produces a more uniform end sample – meaning better quality control and greater certainty of prototype or final product feasibility.  A controlled spray rate, together with flexibility over application distance and dwell time, allows for optimisation of the impregnation / bonding process.  The new equipment, at NIRI’s state-of-the-art Leeds facility, is designed to apply the binders through microdosing, using spray jet streams running over a conveyor system.  A transport conveyor supports and carries a substrate or medium while a microdosing unit comprising of up to three flat spray nozzles sits above the conveyor.  A suction slot, in-line with the spray nozzles, runs under the conveyor.  Thus, samples are belt-fed through the spraying rig where the spray applicators with their controlled flow rates apply the binder formulation to the unbonded web.  Once sprayed, the web is then fed into a through-air oven to consolidate the fabric, and additives can also be used to impart specific functional properties to the final fabric.
 
Compared to alternative processes such as submerging or padding, the spray bonding technique available to NIRI’s customers has some potential benefits, not least improved product performance and greater sustainability.  The technique requires reduced quantities of binder and water, with lower water consumption during processing and less energy is consumed during heating and drying.  Given increasing consumer demand for sustainability and now that we are in the midst of an energy crisis, these can present significant commercial and reputational advantages.  As the process allows for the maintenance of all or most of the loft of the fibre matrix, the low volume density characteristics are largely retained, meaning enhanced product quality.