Controlled granulation of IPCO’s Rotoform system delivers free-flowing beads
Innovation in laundry detergents has seen the development of a range of new products in recent years, from convenient pre-measured laundry pods and dissolving ‘tiles’ to detergents specifically formulated for low temperature or short cycle ‘freshen up’ washes.
In parallel with this, manufacturers have created what is essentially an entirely new sector in the form of ‘laundry boosters’, products that are added to the wash and dissolve in the cleaning water to impart a long-lasting fragrance. They do not replace the detergent itself, nor do they soften fabrics like conditioners do: their job is to leave everything in the laundry smelling fresher.
First introduced just 15 years ago, scent boosters now represent a significant and fast-growing market. Its current value is estimated to be in excess of US$440 million, with growth driven by the rapid adoption of the product in new markets such as eastern Europe and Asia, and the availability of a mind-blowingly wide range of perfumes. Where once the choice was limited to ‘Fresh’, consumers can now freshen their wash with every ‘outdoor’ and floral scent imaginable, from lavender, jasmine and pine to citrus, vanilla and hibiscus.
Scent boosters are generally supplied as beads, a form that has proven extremely popular for its easy, mess-free application, ability to be used in all types of washing machine including high-efficiency (HE) models, and slow-release properties that result in a longer lasting fragrance. Just throw a handful into the wash and leave them to add a scent layer.
The product is created by combining the chemical perfume or fragrance oil with a water-soluble carrier material such as polyethylene glycol (PEG) or polyvinyl alcohol (PVA). Once combined, it then has to be converted into beads, and one of the most widely used systems for this is IPCO’s Rotoform.
First developed in the late 1970s for the granulation of sulphur, the Rotoform system has gone on to become the default choice for the pastillation of an extremely broad range of chemical products (including many of the oleochemicals that are key to the production of laundry detergent products).
In the 50+ years since the first Rotoform was used to convert chemicals into solid beads, the system has undergone significant evolution and improvement, resulting in the development of a range of models capable of handling virtually any chemical product. Beads can be produced in sizes from as small as 0.8 mm to 36 mm in diameter, and throughput capacities range from 0.5-15 t/h.
The system used for the production of laundry boosters would typically be the Rotoform 4G, the latest model to form the foundation of the range and the result of more than five decades’ experience in chemical granulation.
Once the perfume and carrier material have been combined, they are delivered to the Rotoform system in the form of a liquid melt and transported to the Rotoform system via heated pipes.
The Rotoform itself consists of a heated cylindrical stator and a perforated rotating shell that turns concentrically around the stator. Precisely metered drops of the product are deposited by the nozzle bar across the whole operating width of a continuously running stainless steel belt. The circumferential speed of the Rotoform is synchronised with the speed of the belt, ensuring that drops are deposited accurately, consistently and without deformation.
A system of baffles and internal nozzles built into the stator provides uniform pressure across the whole belt width. This ensures an even flow through all holes of the perforated rotary shell to ensure beads of a uniform shape and size from one edge of the belt to the other.
As the droplets travel along the system, heat is transferred from the product to
cooling water sprayed against the underside of the steel belt and the droplets solidify. The cooling water and product do not come into contact with one another so there is no possibility of cross contamination.
The solidified product is then discharged in the form of solid, hemi-spherical beads at the end of the cooling system. The size of the bead is determined by the perforations in the shell of the depositor, and easy changeover of the shell allows different products and bead sizes to be handled on the same system.
The key advantages of Rotoform pastillation include the production of a consistently-sized, premium-quality end product that maintains the key properties of the different ingredients. It is a proven process – more than 2,500 systems have been installed worldwide – and one that offers exceptional levels of reliability.
It is also a process with low environmental impact. The large heat exchange surface of the steel belt delivers fast, energy efficient solidification, and the indirect cooling system means the cooling water can be collected, re-cooled and used over and over again.
And as far as the end product is concerned, pastillation offers advantages over both liquids and powders, being clean to handle and easy to use.