04.2025 | Fachartikel
Dispersing for high product quality of adhesives and building materials
Adhesives, resins and sealants have special processing requirements. The often highly viscous, sticky and difficult to mix substances require specific process technologies for homogeneous results.
Jetstream mixers and inline dispersing machines have established themselves as key process approaches. The Conti-TDS technology from mechanical engineering company Ystral has also been specially developed for the controlled introduction of powders into liquids. These methods enable the targeted dispersion of even viscous media. The decisive factor here is the creation of isotropic properties, i.e. an even distribution of the product properties in all directions. In mixing technologies, this is achieved through targeted turbulence. A common problem in powder processing is the formation of dust and the uncontrolled reaction with solvent vapours. By using vacuum technology, powders such as fumed silica or cellulose fibres can be dispersed efficiently and without agglomerates. Dr Hans-Joachim Jacob, process and application expert at Ystral, emphasises the advantage of this principle: ‘The particle spacing increases, wetting each individual particle immediately. The production process can then be reduced from ten hours to ten minutes.’
Controlled process conditions
The adhesive systems processed include urea-formaldehyde resins, melamine and phenolic resins as well as combinations of these ingredients. Controlled process conditions are required, particularly when processing variants containing fibres or fillers. For moisture-resistant applications, such as the production of OSB or HDF boards, polyurethane-based prepolymers that react with moisture are used. Processing is carried out in the absence of air humidity to prevent unwanted curing. Two-component systems such as polyurethane or epoxy resin adhesives also require strict separation of resin and hardener. Even the slightest mixing can lead to an uncontrolled reaction: ‘If only traces of the hardener come into contact with the resin, the component starts to react,’ explains process specialist Jacob. "Temperatures can rise to 400 degrees - and that's when it gets dangerous." Adhesives based on polychloroprene, methacrylates or silicates also benefit from the modern process technology. Dispersion with Conti-TDS significantly shortens processing times. Bitumen sealants can be modified with layered silicates that are delaminated using vacuum technology. When processing liquid silicates (water glass), solid additives can be added, for example to produce sealing mats. Other applications include odorless packaging adhesives, electrically conductive adhesives for electronics or flame-retardant systems based on aluminum or magnesium hydroxide. Mobile systems for the production of concrete aggregates directly on construction sites can also be realized. Users benefit not only from the flexibility of the processes, but also from their energy efficiency: the short dwell time in the dispersion zone minimizes the temperature input to below two degrees. The systems can also be modularly integrated into existing processes.
Magazine: Chemistry Technology
Author: Ansgar Kretschmer
Publication date: 04/2025
About ystral
With our vast knowledge and many years of experience in Process- and Application Engineering we offer targeted, customer-oriented solutions across industries - from lab equipment to production machines or plants.
Together with you, we develop concepts and implementations for your individual applications, which mean mmediately realisable and quantifiable added value for you.
