Vertical form fill seal machines are commonly used to form pouches. This paper aimed to optimize the sealing parameters and evaluate the runnability of flexible paper-based packaging materials with a polyethylene coating, differentiated by their grammages and thicknesses. This was done in comparison with a commercial plastic film, an oriented polypropylene and polyethylene laminate, using two different sealing jaw patterns in an industrial-scale vertical form fill seal machine. Based on the results obtained, the first observable seal was found at a sealing temperature of 90 °C for the paper-based material and a sealing temperature of 100 °C for thermoplastic film, both at a dwell time of 2 s. It was shown that the paper-based material had a larger sealing window, up to a sealing temperature of 220 °C, before the material started to turn brown, while the thermoplastic film shrank at a sealing temperature of 140 °C. Several peel and compression strength tests were performed to evaluate the flexible paper-based material. Furthermore, several hindering issues were observed in the paper-based material during the production runs. These included wrinkling, web buckling, friction in the forming tubes, pouches airtightness, etc. As such, recommendations for further investigations and future studies are given.

The 440C martensitic stainless steel is considered to be among the hardest steels, owing to its high carbon content. Careful heat treatment of this material introduces multiple carbide particles, which can alter microstructure and mechanical properties. This study focused on the effect of austenitisation temperature on the microstructure and tensile properties of 440C steel. Austenitisation was performed on the austenite + carbide region, because 440C steel lacks a single-phase region. The steel was austenitised at two different temperatures; namely, 1160 °C and 950 °C, and subjected to oil quenching. The as-quenched samples showed a typical lath martensite structure with retained austenite phase. The treatments at 1160 °C and 950 °C promoted the formation of M7C3 and M23C6 carbides, respectively. The austenite grains in the sample treated at 1160 °C showed a higher growth rate than those in the sample treated at 950 °C. The sample treated at 1160 °C showed low-fraction and a large-size carbide phase. The Zener pinning force decreased, thereby increasing the austenite grain growth in the sample treated at 1160 °C. The hardness and 0.2% proof stress of the sample treated at 950 °C were higher than those of the sample treated at 1160 °C, owing to the higher martensite content in the former. The strength–ductility balance of the sample treated at 950 °C was higher than that of the sample treated at 1160 °C. The decreased austenitisation temperature resulted in improved mechanical properties of the steel. Therefore, the austenitisation temperature alters the microstructure and mechanical properties of 440C steel.

With the growing emphasis on minimization of global plastic waste, flexible fibrebased packaging has gained significant interest over the past few years. Heat-sealing technology is commonly applied for vertical form-fill-seal machine to provide tight closure of packages for maintaining food quality and shelf life. Several different seal bar geometries and adequate heat-seal parameters are required to improve the seal tightness of the packages. This study aims to compare the heat sealability of thermoplastic film (OPP/PE) and paper-based materials in vertical form-fill-seal machine using various seal bar profiles. The investigation includes seal strength measurement, understanding the causes of leak formation, seal tightness and inspection of the seal using scanning electron microscopy. Results reveal that OPP/PE material has exceptional seal strength and leakproof ability compared with paper-based materials. However, it has limited operating window because the material shrinks and coarsens at approximately 140 C. Sealing temperature and dwell time are found to be the major factors affecting the seal strength of paper-based material. Results reveal the PEcoated papers exhibit nearly twice the seal strength compared with the dispersioncoated paper. It was difficult to achieve good hot-tack values with dispersion-coated paper. During testing, all the paper-based materials experience delamination and fibre tear, and its severity increases with the increasing material grammage. As plateau temperature is reached, the fibre delamination remains relatively constant. The serrated geometry of seal bar design plays a significant role in providing a satisfactory airtight seal, particularly around the pouch's layer jump. However, flat seal bar designs are not recommended for gas tight applications for paper-based materials.

Over the course of history, there have been three major industrial revolutions, each of them powered by the technological advances of the time and characterized by an increased productivity of industrial processes. Industry 1.0 incorporated the use of hydropower, steam power, and the

Paperboard based packaging products are renewable alternatives for packages made traditionally from oil-based polymer materials and can be used for packaging of various products [1]. Embossing is used in packaging solutions to increase the functionality and appearance of the products. It can also be used to increase product safety by improving distinctiveness and identifiability of packages [2]. The aim of the study was to evaluate the patternability of various fibre-based materials. It was desired that the accuracy and details of the embossed pattern would be the same in all samples, regardless of their different material properties. The realization of this was evaluated by several analyses related to the performance of the materials in the embossing process. Eleven different sample materials were collected for the experiments so that the patternability could be studied extensively. The common denominator of the materials selected for testing was that they were all fibre-based paper and paperboard materials used in the packaging industry. Set of embossing tools were developed, and precision machined from brass, for the experiments. A laboratory scale mechanical embossing device was utilized in modification of sample surfaces to study patternability of selected fibre-based sample materials. The main variables in the forming experiments were pressing force and tool temperature. The samples were observed primarily visually - with the naked eye, with a scanning electron microscope and a 3D-profilometer which was used in the topography analysis of the achieved patterns. The results of the embossing test series confirmed that the height of the pattern increased as a function of pressing force and plate temperature and spring back occurred in all materials after the tool plates opened. It was deduced that the pattern dimensions of the embossing plate somewhat determined the achievable pattern height in the fibre-based sample materials, but the amount of springback did not change as a function of material thickness. Despite this finding, it was consistent that the amount of spring back was regularly reduced with higher tool temperatures. The optimization study of the magnitude of the forming force showed that excessive use of force is not required, which is beneficial in reducing the risk of material damage during processing and adjustment of embossing devices. All samples differing significantly from each other were found to be suitable for embossing, indicating that patterns such as those tested could be added to a variety of packaging applications.