As a long-term specialist in the field of microencapsulation for the production of carbonless papers, Koehler is also familiar with adapting this technology for other industries, especially for the production of fragrance capsules.
Since we started producing our own microcapsules in 1974, the technology has been regularly developed and our own production facilities have been adapted accordingly. Our own patents in the field of microencapsulation and more than 40 years of experience have made us Europe’s leading manufacturer of carbonless papers. With this knowledge of process development and large-scale production, we concentrate on what is feasible in order to also support external customers as a contract manufacturer.
Although it is not often visible to the
naked eye, microcapsule technology can be found in a wide range of familiar,
everyday products. This versatile technology offers solutions for many
innovative products. The enormous spectrum of applications can be found in
markets ranging from Paper industry to Home Care Products. Microencapsulated
actives can be dosed sparingly improving both profitability and sustainability
of many products. Examples how microencapsulation adds functionality to active
components are given below.
In addition to the use of microcapsules in the
paper industry, innovative marketing concepts rely on microencapsulated
fragrances in scented coatings for targeted customer acquisition.
Include phase change materials (latent heat storage) e.g. for construction chemicals, 2K adhesives for threadlockers and encapsulation of healing agents for self-healing paints.
Microcapsules have long been part of everyday life without us being immediately aware of it, among other things as fragrance capsules in fabric softeners and detergents.
Microencapsulation is a generic term for various techniques which envelope substances in the micrometer range with a shell. The aim is often to protect active ingredients and release them in a targeted manner at a specific point in the application.
The chemically and mechanically stable capsules are based on aminoplast resins, for example. In addition to the high impermeability of the capsule shell, the wall is highly resistant to reactive chemicals. The core liquid can be released again selectively by pressure and shear. Microcapsules can also be made from biopolymers, which ensure biodegradability after application.
The properties of a microcapsule’s polymer shell
are defined by its thickness and degree of cross-linking. This is used to
manipulate the diffusion-controlled release of the core material. In the agrochemical
sector, long-term fertilizers benefit from the depot effect of the slow release
of nutrients. The continuous release over time of microencapsulated biocides increase
the efficiency of the agents in antifouling coatings.
Deliberately releasing a substance at a defined
point in time in the application is a very complex task. Pre-applied
thread-locking systems are an example of this principle in automotive industry.
The adhesive is applied to the screw together with the microencapsulated
initiator. Upon thightening the screw, the capsules are destroyed and the screw
is glued and simultaneously sealed to the thread.
Depending on the capsule structure, various opening mechanisms (triggers) such as temperature, UV light, enzymatic activity, or a change in pH value are conceivable. The specific adaptation of wall material and opening mechanism requires a individual solution that can be realized within customized development project.
Release on demand
Pressure and friction are the most common opening mechanisms used in the industrial application of microcapsules.
Fabric softener with a long-lasting fresh scent is now considered state-of-the-art in the detergent and homecare industry. Microcapsules with a diameter of 20 µm to 30 µm, filled with perfume oil, are evenly distributed on the laundry and adhere to the fabric. When wearing the clothes, the capsules burst due to friction and immediately release the fragrance. With every further movement, this process repeats itself and produces a long-lasting fresh scent.
Permanent core / Shell capsules
PCMs (phase change materials) store the latent heat that causes a change of phase from solid to liquid. When the environment cools down, the stored heat energy is released again. The microcapsules’ permanent shell, optimized specifically for this purpose, must be impermeable but still flexible to guarantee that the encapsulated wax can permanently change phase and that the capsule functions properly.
© 2016 Koehler Innovative Solutions