European Commission logo
English English
CORDIS - EU research results
Content archived on 2024-06-18

New weather-stable low gloss powder coatings based on bifunctional acrylic solid resins and nanoadditives

Final Report Summary - GLOW (New weather-stable low gloss powder coatings based on bifunctional acrylic solid resins and nanoadditives)

Driven by the strict European VOC (Volatile Organic Content) legislation and the growing demand for high performance organic coatings, the coatings industry has recognized the significant technological and economic benefits that can gain from (a) replacing conventional with alternative, environmentally friendly technologies (e.g. powder and high solid systems) and (b) adopting advances in nanotechnology. In this context, the main goal of the GLOW IAPP project has been to develop new polymeric binder systems as well as the improvement of key production processes, towards new families of powder coatings. Powder coatings comprise a dry coating technology with significant advantages over conventional liquid paints, as they ensure the elimination of VOCs, high efficiency of material usage and improved coating durability. Weather-stable powder coatings that form matt or semi-matt films with consistent quality are an important but also highly challenging application field for powder coatings systems worldwide. A powder coated surface with reduced gloss is conventionally obtained when introducing certain matting additives in the powder paint formulation. However, the use of matting additives can downgrade the mechanical properties of the coating. An alternative option for producing coatings with reduced gloss is mixing powder coating resins with different reactivity, however the dry blends have several disadvantages (poor batch-to-batch reproducibility, higher manufacturing costs). On the other hand powder coatings manufacturing is a relatively complex, multi-stage operation that must be carefully controlled to ensure high-quality final coatings. The main processing steps include: (a) Pre-mixing (dry blending of the polymer binder granules with the necessary additives), (b) Extrusion of the pre-mix to form a homogeneous dispersion), (c) Solidification process (i.e. cooling the processed material via an industrial cooling belt and flaking it using a breaker), (d) Milling / classification (milling and sieving of the chips to produce a fine powder with a specified particle size range).
Based on the above the specific S&T objectives of the GLOW project included:
- filling S&T gaps in typical powder coatings technologies by pursuing the development of (semi-) matt powder coatings by a simpler, cost-efficient process, in which all formulation components are subjected to a single extrusion step. More specifically, the project focused on the introduction of an one shot extrusion technology combining newly developed acrylic resins and conventional polyester resins;
- the improvement of the optical and mechanical properties of the new but also conventional powder coating systems (given that low gloss powder coatings have typically inadequate mechanical properties), by investigating the effect of the incorporation in the respective formulations of different forms of a wide range of special nanoadditives;
- the consideration of advanced process control methodologies to improve key powder coating manufacturing processes (with emphasis on extrusion and solidification but also on polymer synthesis reactors),
- the assessment of the commercialization potential of the newly developed polymer binders and powder coatings through their validation based on industrial standards and practices as well as a detailed market analysis of the powder coatings sector.
The development of the new resins and powder coatings required a clearly interdisciplinary strategy integrating materials and coatings related research with engineering and industrial practices. In this context, the project encompassed successfully fundamental and industrial research (with emphasis on polymer and composites synthesis) with more applied aspects, which involved process design and control and set-up of production procedures. The progress of the technical activities were significantly promoted by the close collaboration of the GLOW team which was composed of 5 partners from 4 countries (Greece, Italy, UK, Israel) bringing together industry (represented by Megara Resins S.A. - Greece, Steel Belt Systems Srl. - Italy, Israel Barter Trading Ltd. - Israel) and academia / research (represented by the National Centre for Scientific Research “Demokritos” - Greece and the City University of London - UK). MEGARA is a fast growing manufacturer and supplier of raw materials for industrial and architectural coatings; the NCSRD group has strong expertise in the synthesis and characterisation of nanostructured materials for diverse industrial applications with emphasis on porous and composite materials; SBS specialises in the design and manufacture of special equipment, for chemical, petrochemical, polymer, food, rubber and coating industries; the CITY group has strong expertise in modelling/engineering of complex, control and information systems for different applications; the core business of IBT is the introduction and marketing of chemicals into the plastics and coatings industries. The team evolved to an efficient inter-sectoral collaborative network by exchanging complementary know-how, as well as combining the practical industrial experience in coatings with fundamental knowledge on materials science and engineering principles offered by the RTD partners.
The S&T work within the project progressed smoothly and has generated significant results that can be summarised as follows:
- lab-scale synthesis of a large number (around thirteen different formulations) of new acrylic resins that can lead to low-gloss powder coatings,
- successful, reproducible synthesis of at least three different types of new acrylic binders that can provide low-gloss powder coatings with consistent quality, a pre-requisite for an entry to market,
- successful incorporation of different types and forms of new nanoadditives (clays, silica- and carbon- based layered materials and nanostructures) in powder coatings formulations with a positive effect on their durability,
- successful larger scale trials (tens of kg) for both the production of resins and powder coatings systems, providing a solid basis for the transfer of the new materials concept in industrial production,
- development of reliable theoretical models describing key powder coatings manufacturing line processes (extrusion, solidification) based on actual real process data, and defining the optimum critical parameters for appropriate control of the overall operation,
- verification of the commercialization potential of the new powder coatings, as shown (a) by the positive outcome of dedicated validation trials engaging external powder coating producers, and (b) a detailed market analysis that was carried out in an attempt to map the developments in the powder coatings market, identify trends but also technology gaps and thus provide a basis for planning the future exploitation of the GLOW product concept.
The implementation and outcomes of the project may have a multifaceted impact, in techno-economic, environmental, social aspects. Powder coatings give consumers and industry one of the most economical, longest-lasting, and most color-durable quality finishes available. The new products developed within GLOW have the potential to replace current technologies for matting outdoor resistant powder coatings, such as the dry blending process which can create quality problems and variation of gloss levels. The new technology is attractive application-wise but is also environmentally benign as the new products are clearly eco-friendly.
In addition the progress made relied to a great extent to the exchange of in total twenty researchers (40% of which, female) between the industrial and RTD organisations but also the targeted recruitment of four highly experienced scientists. The seconded/recruited researchers were offered valuable opportunities for developing mobility, work experience in different environment and new collaborative networks. In addition they advanced significantly their technical skills, diversifying their overall professional experience and reinforcing their research maturity and potential, by receiving high quality and clearly interdisciplinary hands-on training in a number of high end S&T areas such as (a) coatings technologies, (b) polymer and nanocomposites synthesis, (c) state-of-art materials characterization methods, (d) process control and engineering, (e) industrial production, (f) business and technology management practices.
More information about the project can be found in the dedicated GLOW website,