Effect of filler additions on pilot-scale extrusion coating of paperboard with PLA-based blends

We study the incorporation of minerals (talc, kaolin and surface-treated calcium carbonate) in paperboard coatings based on PLA to improve their performance, often limited by the low crystallinity and moderate gas barrier of the polymer. Masterbatches of PLA-based blends mixed with the mineral fillers were melt-blended in a twin-screw extruder and applied as a coating on paperboard in a pilot-scale unit operating at velocities up to 140 m/min. Thermal imaging was used during the extrusion coating and the effect of the fillers was investigated as far as processability and their effect on the mechanical performance. A reduction of neck-in and improved adhesion between the coating and the substrate were achieved at intermediate mineral loadings. Excess filler and low coating weight generated pinholes, leading to a reduction of the integrity and mechanical properties of the coatings. Overall, we define the performance window for continuous, pilot-scale coating of paperboard with a biopolyester filled with mineral particles, opening the opportunity to realize operations in industrial settings.

Development of PosMAC® Steel and Its Application Properties

PosMAC® is a hot dipping Zn-Mg-Al coated steel sheet developed by POSCO. PosMAC®3.0 shows excellent anti-corrosion performance and is suitable for construction and solar energy systems in severe corrosive environments. PosMAC®1.5 has a superior surface quality and is preferred for automotive and home appliances. The advanced anti-corrosion properties of PosMAC® comes from a dense corroded layer which forms on coated surfaces, compared with traditional Zn coatings such as GI, GA and EG. PosMAC® steels show superior corrosion protection compared to GI coatings in cyclic corrosion tests, despite an approximate 30% reduction in coating weight. The PosMAC® has excellent application properties for the arc welding of automotive chassis. It has a heat resistance that is more robust than the GI coating, and maintains excellent corrosion protection near the welds of the chassis. Zn-Mg-Al coatings, whose chemical compositions are similar to PosMAC® coatings, have very low surface friction properties compared to the GI coating. The friction coefficient of PosMAC® is stabilized to 0.09~0.11. In contrast, the GI coating showed higher friction coefficients of 0.2~0.3 in the repeated friction test. PosMAC® would be appropriate for complex forming parts with less galling, given these low friction resistance properties. It is expected that the industrial demand for PosMAC® steel will increase in the near future, thanks to its Zn saving and high anti-corrosion performance.

Ultrasonic welding of folding boxboards

Today’s environmental concerns are pressuring industries to substitute paper-based materials in place of plastics in many sectors including packaging. However, assembling papers and paperboards using environmentally friendly solutions remains a technological challenge. In this context, ultrasonic (US) welding is an alternative to adhesives. In this work, the potential of US welding to assemble folding boxboards was investigated. Folding boxboards are commonly coated to enhance printability. This coating is generally composed of mineral pigments (85 to 90%) and polymer binders (10 to 12%). This study evaluated whether the presence of the coating layer allows the assembly of paperboards by US welding. Results indicated that welding coated folding boxboards is possible provided that coating weight and binder content are high enough. The mechanical performances of the welded boards met the requirements of most packaging applications. Adhesion in the welded joint resulted from a combination of thermoplastic (melting and flowing of the binder) and thermoset (degradation reactions) effects. However, it was not possible to assemble coated folding boxboards without degrading the welding zone. While the materials and process need to be optimized, this work represents a big step forward toward the adhesive-free assembling of paper-based materials.

Influence of coating grammage on the utility properties of coated papers

Influence of coating grammage on the utility properties of coated papers.The paper coating offers the opportunity to create a product with high added value, the potential of which has been recognized by both paper mills and polygraphs.Indeed, paraffin coatings have excellent barrier, sliding and strength properties, and also increase the quality and durability of the print. This paper presents the results of the research on the influence of the coating weight on the functional properties of the coated paper. To this end, a commercially available paper was coated with a paraffin emulsionusing various Mayer rods and then tested using standard mechanical, surface, and water absorption tests. It was found that the coating of the base paper, regardless of the amount of the applied mixture, significantly influences its hydrophobic, surface, and strength properties. Papers with the highest coating weight allowed to obtain a paper with increased strength and high surface smoothing. The completed coatings significantly increased the water barrier, regardless of their thickness

The Effect of Zno Nanoparticles on the Color Change of Polyester

In this study, the effect of adding zinc oxide nanoparticles (ZnO) on the general color change and transparent adhesion strength of polyester folds was studied in wood (Ulmusglabra). Zinc oxide nanoparticles with concentrations of 0, 0.22, 0.20,1, 1.20 and 2% of coating weight were combined. In a study about adherence resistance of coating the results showed that the highest adhesion in Nano coatings contained 1% nanoparticles of zinc oxide, and adding more than this had a negative effect on the adhesion of coating. In the case of general color change, the addition of zinc oxide nanoparticles is also caused a change in the color of samples coated with nanoparticles. However, in small amounts of nanoparticles, color changes were made and the brightness reduction was not significant.

Characterization of Phosphate Coatings: Influence of the Acid Pickling Conditions

This research emphasizes the importance of the acid cleaning prior to the phosphate development on high-strength steel rods. It compares the phosphate properties achieved after different acid-pickling conditions. The most common inorganic acids were considered in this study. Additionally, taking into account the environmental and safety concerns of these acids, the assessment of a less harmful organic acid is presented. This study revealed significant differences in the coating morphology and chemical composition whereas no great changes were found in terms of the coating weight or porosity. Thus, hydrochloric and sulfuric acid promote the growth of a Fe-enriched phosphate layer with a less conductive character that is not developed after the pickling with phosphoric acid. The phosphate developed after the citric acid pickling is comparable to that developed after the inorganic acids although with a porosity slightly higher. The temperature of the citric acid bath is an important parameter that affects to the phosphate appearance, composition, and porosity.