An especially critical issue is that viscous coatings require stirring before they can be used. However, even the immersion of a stirrer carries the potential risk of contamination. Every time the packaging is opened or closed and any form of contact with other equipment can cause contamination. With these potential risks along the supply chain, it is reassuring to know that packaging manufacturers, fillers and consumers can work together to prevent this happening. Together, these stakeholders can significantly increase efficiency in the day-to-day handling of coatings.
Teamwork for gleaming coating results
Schütz has been supplying Karl Wörwag Lack- und Farbenfabrik with IBCs since 2003. The coating manufacturer, headquartered in Stuttgart-Zuffenhausen, develops and produces high-quality paints for a wide range of industrial applications: from vehicle interiors and exteriors to car bodies, commercial vehicles, household appliances and the furniture industry. The business relationship with the packaging manufacturer from Selters in Westerwald has grown steadily over the years. Schütz also works closely with Samvardhana Motherson Peguform (SMP Automotive), a major customer of Wörwag. The specialist for plastic-based components supplies major automobile manufacturers in Europe, China, Mexico, Brazil and the USA with ready-coated bumpers and other car body parts.
Wörwag and SMP were seeking a solution to minimise the risk of contamination during filling and subsequent processing of clear coatings and primers. Schütz had the ideal packaging: an IBC from the Cleancert line configured to support the process with an Impeller and an S56x4 bung. Thanks to the integrated Impeller, the container can remain closed throughout the entire supply chain from filling to emptying. At the same time, the contents can be easily and effectively stirred. Conventional stirrers are no longer required and the risk of contamination is significantly reduced. The system is available for all 1,000 and 1,250 litre Ecobulk types with DN 150 and DN 225 filling openings. “These advantages absolutely convinced us, and that is why we use Schütz's Cleancert IBC for clear coatings and primers as these products are particularly sensitive to surface defects”, says Benno Beuter, application engineer at Wörwag. The coatings specialist orders empty IBCs which are delivered and stored in-house as a further safety and hygiene measure.
At Wörwag’s customer SMP the filled containers are also delivered to a covered area and stored under roof. The Cleancert IBCs score yet again at the automotive supplier’s central warehouse, particularly in comparison to the steel containers previously often used for these purposes. Up to four IBCs can be stacked on top of each other – instead of only two steel containers, meaning that the Cleancert models also ensure that the available space is used more efficiently. The downtime of empty containers is also significantly reduced to a maximum of seven days thanks to collection by the Schütz Ticket Service. Empty steel containers remained in the plant for up to one month, which occasionally caused bottlenecks in the company’s warehouse.
Lower speed – gentle stirring process
During processing in the air-conditioned paint mixing room, clear coats, primers and base coats are continuously stirred to ensure a homogeneous consistency. In order to determine the advantages of the Cleancert IBC + Impeller closed packaging system in practice, SMP conducted a series of tests, each lasting several weeks. The disposable stirrer is connected to the screw cap of the IBC and is fitted at the Schütz factory. A conventional drive system can be connected without requiring major modifications or conversions. In the SMP test series a model by the agitator manufacturer Planetroll was used. If required, as part of its services, Schütz will arrange contact with this cooperation partner. Planetroll is very familiar with the system, and the company’s portfolio includes complete drive solutions with all the necessary components such as transverses, couplings and steel shafts. The drive is placed above the screw cap and fixed to the steel grid with a frame. The drive shaft is inserted into the hollow shaft of the Impeller and fits in the hub; the rotation of the shaft is passed on to the Impeller inside the container. The three movable blades of the Impeller’s bucket agitator change their position depending on the centrifugal force. The speed can be individually adjusted to the filling level.
The result of the comparative test: with external steel stirrers, 140 to 200 revolutions per minute were required for homogenisation. This high speed led to increased microfoam formation due to air intake into the product. When stirring with the Schütz Impeller, however, 80 to 110 revolutions were sufficient. The lower speed ensured gentle stirring processes with optimum results. Anton Krojer, the SMP application engineer in charge of the test series, is highly satisfied with the positive test results: “Thanks to the efficient stirring processes, we no longer need preparatory homogenisation measures prior to a container change.” Since the IBC including the Impeller and traverse drive can be transported flexibly and considerably less time is required for homogenisation, it was possible to connect the container directly to the production line after the drive had been installed and feed the paint in directly. This eliminates the need for a previously required preparatory step at an additional station. The company uses the S56x4 bung to take samples for viscosity measurement and / or to add setting or correction agents, if necessary, during the stirring process.
“The use of the Impeller as a disposable system completely rules out the risk of contamination due to residual product adhering to the stirrer. This greatly increases process reliability”, explains Manfred Guttmann, head of the paint shop at SMP. “This eliminates the complex and time-consuming cleaning process for the agitator, as well as other risks. Employees no longer have to handle solvent-based cleaning agents which greatly improves work safety.” The multiple-week test phase in the production of components for bumpers using Cleancert IBCs and Impellers impressively confirmed all theoretical aspects of the optimisation and revealed business management advantages: SMP was able to dramatically reduce the amount of work spent on corrections. This special cooperation showed how important it is to involve all companies along the supply chain.
Prevention during the production of Cleancert products
Cleancert offers the highest level of technical cleanliness and safety for product and process; all components that come into contact with the filling product are free from silicone. The initial idea for the development of this product was the certification of all production sites according to the industry standard FSSC 22000, combined with the implementation of numerous specifications within the framework of the HACCP and FMEA standards. These apply to buildings, plants and the entire production environment. One aspect is detailed hygiene regulations. For example, employees must change their gloves and clean the workplace before starting production. There are also measures to prevent contamination or dust, as well as glass and blade management procedures. Maintenance regulations and checks on the machines, systematic pest control throughout the entire factory premises, requirements for the controlled use of all working materials, especially greases and lubricants, and a secure goods receipt complete the package.
Schütz manufactures the Cleancert packaging just-in-time on the basis of specific customer orders: the IBC inner bottles are transferred to the final assembly stage and installed immediately after the blowing process. Each production step and each component can be clearly assigned to the corresponding packaging. Identification via a barcode system enables complete traceability, right down to the batch and process level. On request, Schütz can also assign individual identification numbers for articles or packaging materials.
Finished Cleancert IBCs are loaded indoors and shipped directly without intermediate storage. Pre-produced components such as screw caps, outlet valves or bung plugs are also hygienically packed in small quantities and stored separately. If dispatch is to take place at a later date, the containers are stored in special closed rooms. Optional plastic covers offer additional protection. Combined, all of these precautions make a considerable contribution to maintaining the quality of the subsequent filling product.