Use of silicone particles to differentiate the touch and feel of coatings

 
The properties of coatings are usually described and characterized by their appearance, e.g. color and gloss. This presentation concentrates on the tactile properties and describes how silicone additives can provide a soft-feel effect to coatings that is comparable to velvet or leather. The latest developments of silicone technology for this application will be introduced, together with results for properties such as scratch resistance and matting effect. Plastics have been used successfully and incorporated at increasing quantities in automotive engineering for many years. Examples of applications include: in the car body, in the passenger compartment and for certain engine components where steel is being replaced wholly or in part by plastics. As well as reducing weight, plastics have a number of other advantages. They provide greater scope for design, the potential for integrating components, improved aerodynamic properties due to appropriate molding, and increased energy absorption in the event of a crash. For greater comfort in the passenger compartment, the plastic parts must be lined with foil and textiles. Most of the foils are PVC foils, which can be problematic for the disposal of old vehicles. Alternatively, coatings can be used because it is much easier to achieve color consistency with coatings than reproducibility of colored plastics. When developing coatings for this application, it is important to avoid the usage of solvents to prevent solvent emissions. Furthermore, an attractive, high-quality surface is desired. Soft-feel coatings have tactile properties, are mainly matte, and both look and feel similar to leather or velvet. They can also improve the weather resistance against sunlight and scratch resistance. Soft-feel coatings are used in other industries, e.g., the electronics industry (computers, laptops, mobile phones) and the furniture industry to obtain a nice to touch, matte, mar-resistant and good-looking surface. If a certain appearance is required, it can be obtained by applying the coating onto a textured plastic substrate. The successful formulation of soft-feel coatings requires the use of certain softer binders, e.g., aqueous hydroxylfunctional dispersions in combination with water emulsifiable polyisocyanates to formulate two-pack systems. The combination of organic and inorganic compounds can further enhance the soft-feel effect but the low Tg of these systems often results in poorer chemical resistance.