Film maker
Film formers ( engl. Film-forming agent ) are macro- or low molecular weight substances (long- and short-chain polymers ), which provide in a coating material for the realization of a continuous film. The most common areas of application for film formers are paints such as varnishes and other coatings , pharmaceuticals such as tablets and capsules, and cosmetics such as hairspray . There are cationic, anionic and nonionic film formers.
The terms film-forming agent and binding agent are often used synonymously, but coating materials can also contain additives that belong to the binders but not to the film-forming agents.
Typical film formers for paints and coatings
Most film formers belong to the category of resins (e.g. acrylic resins , alkyd resins , polyurethanes ( synthetic resins ), epoxy , phenolic, urea and melamine resins ). Further, cellulose nitrate , chlorinated rubber , PVC copolymers used. The film formers are used both as liquid resins and as solutions in solvents and also as dispersions in water.
Typical film formers for cosmetics and pharmaceuticals
Are frequently used polyvinyl pyrrolidone , polyvinyl alcohol , polyethylene glycols , polysaccharides such as cellulose derivatives , polyacrylic acids (carbomers), copolymers of vinylpyrrolidone and vinyl acetate , protein hydrolysates , proteins such as sericin , natural resins such as shellac , rosin , benzoin and sandarac . Depending on their solubility, these film formers are used as a solution in water or in ethanol . Cationic polymers from the group of polyquaternium compounds , z. B. in hair setting agents and shampoos. Water-soluble silicone derivatives that improve smoothness and combability are also used here . In addition, algae extracts are also used as film formers. In ophthalmology , water-soluble products such as hypromellose , polyvinyl alcohol, polyvinylpyrrolidone and polyacrylic acids are used in "artificial tears " when there is insufficient tear production.
application
When using it, it should be noted that if the surface to be treated is expected to be subject to high mechanical stress, film formers with high molecular weights (long-chain polymers) are required. However, these are more viscous than low-molecular film formers, which is why the mixing ratio depends on a balance between viscosity (processability) and durability. In the pharmaceutical industry, water-soluble film formers are used to keep tablets and capsules stable and to protect them from moisture. Depending on whether an active ingredient is to be released in the stomach or in the intestine, acid-soluble or acid-resistant film formers are used.
Health hazards
If used incorrectly, film-forming agents can build up in the ear canal and clog pores . Inhaled, for example through hairspray, film formers can be harmful to health. As microplastics , they can accumulate in the lungs, hinder the bronchial tubes from cleaning themselves and lead to inflammation . In wastewater , substances that are used as film formers can not be completely filtered out by sewage treatment plants and can get into the environment. In skin cosmetics, film formers from petrochemicals such as paraffins and petroleum jelly are controversial. Critics point out that they affect the metabolism, can make skin and hair brittle and contain potentially carcinogenic "impurities" such as unsaturated hydrocarbons .
textiles
Since compounds from the cationic polyquaternium group also accumulate on textile fibers, color and dirt pigments from the anionic washing liquor can more easily adhere there and cause discoloration accordingly more quickly.
literature
- Hubert Gräfen (Ed.): Lexicon of Materials Technology: Corrected reprint , VDI-Gesellschaft Werkstofftechnik, Heidelberg 1993, p. 595
- Klaus-Peter Müller: Practical surface technology: pretreatment - coating - coating defects - environmental protection , Braunschweig / Wiesbaden 2003, p. 177
Individual evidence
- ↑ a b c Entry on film formers. In: Römpp Online . Georg Thieme Verlag, accessed on November 17, 2018.
- ↑ Uta Schumacher, Thomas Feist, Dennis Lehmann: The Study Book of Painting Technology - Basics, Tasks and Exam Questions for Process Mechanics in Coating Technology , p. 39, Publisher: Vincentz Network, 6th edition.
- ↑ Artur Goldschmidt, Hans-Joachim Streitberger: BASF-Handbuch Lackiertechnik , Hannover 2002, p. 26 ff.
- ^ Siegfried Lang, Peter C. Schmidt: Pharmaceutical auxiliaries: Properties, application and commercial products , Eschborn 2013, p. 95.
- ↑ https://www.berlin.de/special/gesundheit-und-beauty/beauty/4582745-219-mikroplastik-in-kosmetika-gut-versteckt-.html
- ↑ Parabens, Silicones & Co - how dangerous are cosmetic ingredients? , on lisa.de