Moulded pulp products manufacturing with thermoforming

Abstract

Over the past years, eco‐friendly packaging solutions such as moulded pulp have resonated with a growing number of consumers. Among all of them, the thermoformed products make use of the most recent manufacturing approach that produces high‐quality, thin‐walled items. However, it remains an underresearched area, and the development of an efficient and precise manufacturing process is fundamental in order to increase the implementation of sustainable packaging. With the purpose of setting a step towards in the standardization of design and testing practices of eco‐friendly packaging, this work focused on the characterization of the thermoforming process of moulded pulp products and their characteristics. Three different analyses were carried out for this purpose, covering the dewatering efficiency of the process, a quantification of the moulding geometrical accuracy, and an analysis of the internal microstructure of the parts. Experimental results and statistical analysis show that the dewatering efficiency is mainly governed by the mould's temperature while the duration of the contact time is not influential. In the second investigation, the geometrical accuracy of the mouldability of microfeatures was assessed. The process appeared to be dependently related to the pulp type employed. Finally, the internal microstructure was documented using X‐ray computed tomography. The analysis shows an increase in the internal void fraction linked with an increase in the mould's temperature. The role of the water change of phase in the thermoforming process is also discussed by reference to the work conducted on impulse drying.

Moulded pulp products manufacturing with thermoforming

“…For this reason, the process parameter "Holding time" is disregarded and not discussed in Didone and Tosello. 1 Due to this conclusion, the interaction between "Holding time"…”

“…Hence from the experimental plan with eight data points presented in Table 1, four data points (highlighted in green in the table) were chosen for the analysis presented in Didone and Tosello. 1 This is due to the fact that, by looking at the main effect plot reported in Figure 9 in Didone and Tosello 1 and considering the physics of the thermoforming process, they were sufficient to draw the conclusions reported in the article.…”

“…Three different analyses were carried out for this purpose, covering the dewatering efficiency of the process, a quantification of the moulding geometrical accuracy, and an analysis of the internal microstructure of the parts. 1 The purpose of this addendum is to present a number of clarifications with respect to the definition of the moulded pulp thermoforming process parameters in order to increase the understanding of the process itself for the benefit of the interested reader. For this additional information, we acknowledge the contribution given in Danielak and Ortie.…”

“…Disregard of the process parameter "Holding time" and subsequent modified selection of experimental data as presented in Didone and Tosello. 1 2. Correction of the process parameter "Vacuum time" to "Cycle time"…”

“…as defined in Didone and Tosello. 1 3. Correction of the process parameter "Temperature" values as presented in Didone and Tosello.…”