Plate-like fillers are often added to improve barrier properties and to prevent blocking of dispersion coatings on paper and board. We have studied the effects of clay addition, neutralizing agent and drying conditions on water vapour permeability, water absorption, oxygen permeability and heat sealability of carboxylated styrene/butyl acrylate dispersion coatings on a pilot scale. The barrier dispersions were applied on a pre-coated side of a three-ply board, using a pre-metering roll coater. Coated strips were sealed under specified conditions of temperature, time and pressure and the sealability was assessed by measuring the peak load necessary to break the joints. The surface composition of the barrier-coated board was analysed and the mode of failure was characterized by ESCA. The occurrence of pinholes in the barrier coatings was assessed by both staining tests and ESEM/EDX analysis of the surface topography. The resulting barrier properties were satisfactory as far as resistance to water transport in both liquid and vapour form is concerned. The oxygen permeability was similar to that of similar amorphous polymers. Heat-sealing tests showed that the mode of failure was mainly cohesive in nature, as fibre tear occurred when sealed strips were separated. Neutralization with sodium hydroxide gave poor adhesion and had a negative effect on the seal strength. Barrier measurements and ESEM/EDX analysis both showed that the pinholes present extended only through the barrier coating
The replacement of flexible polyolefin barrier layers with novel, thin, functional polymer coatings in the production of paperboard packaging involves the risk of deteriorated barrier and mechanical properties during the converting process. Local defects or cracks in the protective barrier layer can arise because of the stress induced in creasing and folding operations. In this study, the incorporation of microencapsulated self-healing agents in coating formulations applied both by spot- and uniform-coating techniques was studied. The preparation process of microcapsules with a hydrophobic core surrounded by a hydrophobically modified polysaccharide membrane in aqueous suspension was developed to obtain capsules fulfilling both the criteria of small capsule size and reasonably high solids content to match the requirements set on surface treatment of paperboard for enhancement of packaging functionality. The survival of the microcapsules during application and their effectiveness as self-healing agents were investigated. The results showed a reduced tendency for deteriorated barrier properties and local termination of cracks formed upon creasing. The self-healing mechanism involves the rupture of microcapsules local to the applied stress, with subsequent release of the core material. Crack propagation is hindered by plasticization of the underlying coating layer, while the increased hydrophobicity helps to maintain the barrier properties.
This study is part of a larger project aimed at establishing criteria to ensure the quality and safety-in-use of recycled and re-used plastics for food packaging. A major concern is that plastic materials can interact with chemicals to a greater or lesser extent. As a consequence, refillable containers may be contaminated by migration of harmful substances into the plastic material due to misuse by consumers before return. On the other hand, there is currently neither any specific national or EU regulation nor a standard test procedure available which could be applied by industry or enforcement laboratories to meet this situation appropriately. In this study, a relative simple inertness test which focuses on the interaction of PET bottle wall strips with a selection of model contaminants was investigated. The model contaminants were selected to include four different sets of chemical functional classes (set A, alcohol-type compounds; set B, ester/ketone type compounds; set C, hydrocarbon-type compounds; set D, chlorinated hydrocarbons). A simple gas chromatographic method using flame ionization detection was developed to allow quantification of the whole range of model contaminants. Linearity and reproducibility of the calibration curves for all contaminants were excellent, which indicates the validity and efficacy of the proposed methodology. The sorption experiments with PET bottle wall strips showed that significant amounts of chemicals can be absorbed into the plastic material if misused, thus establishing a remigration potential in the bottle material after refilling. © 1997 by John Wiley & Sons, Ltd.
The purpose of this work was to study the packaging supplier and the integration of integrating packaging suppliers into the supply and demand chain (SDC). The packaging industry has been analyzed using a structured market analysis, and the companies studied have been positioned in an integration model for packaging suppliers. In addition, case studies were conducted to study the development of the packaging industry and its integration within the SDC in the Scandinavian region. The analysis shows that there are gaps in the business relations between the packaging companies studied and the SDC. Most of the packaging suppliers were not integrated into the SDC. Valuable information, available in the network, seldom reaches the packaging supplier who holds the knowledge necessary to create and offer innovative packaging solutions. The article provides an empirical exploration into the field of packaging, logistics and SDC integration and an original conceptual framework that could serve as a theoretical framework for future research work applied in the packaging industry and an interesting business model to the increase understanding of packaging supply chain integration.
This paper summarizes the dynamic analysis of the interaction of corrugated boxes in transport using a pressure-mapping system. The dynamic contact forces on the contact area between boxes in both vertical and horizontal directions were measured, and the position of the instantaneous centre of force was traced, from which the pitch motion of boxes relative to each other was studied. The level-crossing diagrams of the contact forces show a Rayleigh distribution for the vertical contact and a Gaussian distribution for the horizontal contacts. The contact force and acceleration power spectral density from accelerometers and pressure-mapping system were compared. The results show that a pressure-mapping system is an interesting tool for the analysis of the dynamic performance of systems of corrugated boxes under different stacking and loading conditions.
The present study investigates torsional and compressive loading of a paperboard package. Finite element (FE) analyses simulating the tests were performed to improve understanding of the stresses and deformations in the paperboard during loading. A simple experimental characterization of the necessary material properties could be performed to represent the multi-ply paperboard as a single-ply structure. The results from the single-ply model were compared with a laminate model, and the differences between the models were small. Comparing experimental and FE simulations of box compression and torsion showed that the FE models could accurately predict the response curves. However, in the simulations, there was an overprediction of the maximum compressive force and maximum torque, which was expected since geometrical imperfections and the heterogeneous internal structure of the material were not accounted for in the material model or the FE model. Local yield lines formed at the onset of non-linearities in the package load–displacement curves. Therefore, the strength of the paperboard affects the maximum compressive strength and maximum torque, and the bending stiffness of the paperboard only had a minor effect. When a first local maximum was reached, the number of FE that reached the failure stress increased exponentially. The simulations also showed that box compression was not an effect of package height, but higher packages had a lower maximum torque. © 2022 The Authors.
Creasing is an essential process to convert paperboards into packages since it enables folding along well-defined lines. The creasing process relies on purpose-made damage that is initiated in the paperboard structure: delamination. However, creasing might also cause in-plane cracks, which must be avoided. In this laboratory study, three paperboards were creased at six different depths, respectively. Two mechanical tests were performed to characterize the creases at standard climate (23°C and 50% RH): 2-point folding, to examine the bending force and short-span in-plane tensile test to evaluate the strength. The results were normalized with the values for the uncreased boards, which gave the relative strength ratios: relative creasing strength (RCS) and relative tensile strength (RTS). When the relative strengths were evaluated against the normative shear strains, a creasing window was formed. This window has an upper limit given by the RTS values, corresponding to the in-plane cracks, and a lower limit given by the RCS values, corresponding to the delamination damage initiated in the paperboard during creasing. It was observed that both the RCS and RTS values exhibit a linear relation against normative shear strain. From this, it was concluded that performing tests at two creasing depths might be sufficient to estimate the lower, and upper, limits for the creasing window in future studies. Finally, the effect of moisture was investigated by creasing, folding and tensile testing at 23°C and 90% RH, which showed that moisture had no clear effect on the RCS or the RTS values.
Finite element (FE) analyses can be used as a powerful tool in the package design process to study for instance stress and strain fields that arise during loading. An orthotropic linear elastic material model with a stress-based failure criterion was used to simulate box compression tests (BCTs) of a paperboard package in the FE solver LS-Dyna. Physical experiments were performed at 50%, 70%, and 90% relative humidity (RH). The input parameters required for the simulations were calculated based on material characterization at standard climate (50% RH and 23°C) and a linear relation between mechanical material properties and moisture ratio established in earlier studies. The result showed that it was possible to accurately predict the load–compression curve of a BCT when moisture was accounted for. Furthermore, it was found that modelling of the mechanical properties of the creases are important for capturing the stiffness response of the package. To conclude, it was possible to predict the box compression strength and the linear stiffness response prior to the peak in the load–compression response at relevant moisture levels, by using the previously established linear relationship between moisture ratio and material properties. In addition to the moisture ratio at the preferred moisture level, the only material properties required were the in-plane strengths and stiffnesses, and the out-of-plane shear moduli at standard climate.
The influence of drying conditions, latex type, talc content and amount of added aroma compounds on the retention and distribution of aroma compounds in barrier dispersion coatings was explored using static headspace gas chromatography combined with multivariate data analysis. The model aroma system consisted of an alcohol, an ester, an aldehyde, a ketone and two terpenes. Four latex grades based on styrene-acrylate and styrene-butadiene were studied. It was found that non-polar aroma compounds were retained best in styrene-butadiene latex, while polar ones were retained more in the styrene-acrylate latex. Talc increased the retention of all the aroma compounds. The retention of polar compounds was higher with shorter drying times, which is probably due to greater losses during the later steps of the film formation process when internal water was evaporated. Polarity and talc also affected the partition of the aroma compounds between air and film. Copyright © 2007 John Wiley & Sons, Ltd.
The potential of various latex grades to take up, retain and release different types of aroma compound has been explored. The latex grades used included two styrene-acrylate latices and two styrene-butadiene latices, of which one contained talc. The aroma compounds used were ethyl butyrate, 1-hexanol, heptanal, 3-octanone, ?-pinene and limonene dissolved in propylene glycol. It was shown that talc improves both the uptake of aroma compounds in the dispersion phase and the retention during the film formation process. However, the styrene-acrylate latex had a greater ability than the styrene-butadiene latex to hold the aroma compounds once the films were formed. These results have been compared to calculated solubility parameters. The uptake of 1-hexanol and propylene glycol in the latex dispersions were higher than expected from the theoretical calculations, probably because of the amphiphilic nature of these molecules. In addition, the influence of aroma compounds on the film formation was evaluated.
Carboxylated styrene acrylate latex samples have been functionalized by the immobilization and entrapment of the enzyme glucose oxidase (GOx), which can be used as an oxygen scavenger in food packaging. GOx was covalently immobilized both on the surface of already formed films and on the latex particles in dispersion, as well as entrapped within the polymer matrix. In the latter two cases, polymer films were formed after the enzyme had been added to the latex dispersion. The storage stability of the enzyme and the influence of adding clay were also studied. For a given amount of enzyme, the enzyme immobilized on the film surface showed an enzyme activity about 10 times higher than that of the enzyme present within the polymer matrix. This is probably due to the diffusion limitations of the substrate in the polymer matrix. The films with the enzyme present within the polymer matrix, however, showed a higher total oxygen-removal capacity than films with the enzyme immobilized on the surface. Entrapped enzyme showed a slightly higher activity than enzyme immobilized in the dispersion due to the negative effect of the activating chemicals used during the immobilization and on conformational constraints upon covalent bonding. Low amounts of clay added to the dispersion decreased the enzyme activity, but with higher amounts of clay the enzyme activity increased, probably because of the increased porosity and thus higher substrate accessibility. The most suitable storage condition for all the enzyme-containing films was +8°C, which is just above the glass transition temperature of the polymer used.
A finite element framework has been proposed that can be used to simulate both empty paperboard packages and package filled with plastic granulates. A gable top package was made of a commercial paperboard, and material properties needed in the material model were determined. Two simulations were performed, a drop test and a compression test. By comparison between experimental and numerical results, the deformation mechanisms at impact could be identified and correlated to material properties. When the package was filled with granulates, different mechanisms was activated compared with an empty package. The granulates contribute to bulging of the panels, such that the edges became more load bearing compared with the panels. When the edges carried the loads, the importance of the out-of-plane properties also increased, and local failure initiation related to delamination was observed. Comparison between experimental and numerical impact forces shows that there are still important things to consider in the model generation, eg, variation of properties within the package, which originate both from material property variations, and the loading history, eg, during manufacturing and handling.
There are several reasons why people find it troublesome to use and handle consumer packages. The European Committee for Standardization recently suggested a technical specification (TS) regarding packaging and ease of opening. The present study has expanded the procedure by including consumer satisfaction measurements in two steps and engaging panels comprising two separate age groups. The expanded method, which used six different packages as test objects, engaged 75 panellists, 40 in the older group (65-80years) and 35 in the younger group (25-40years). The expanded method not only included the same operations as described in the TS but also included panellists who graded each handling element separately on a 'smiley' scale, along with feedback for their grades and an overall judgement of the package handling. The grading feedback differed between the two groups. The younger panellists mainly noted issues that were not connected to openability, while older panellists noted openability as the most influential factor. Further analysis revealed that openability was also a key issue for the younger panellists, despite their claims to the contrary. Satisfaction was the most critical TS element for describing a package as being easy to open.
The purpose of this article is to develop an evaluation model for the selection of packaging systems in supply chains from a sustainability perspective. A theoretical evaluation model for comparing cost efficiency and the environmental impact of packaging systems in supply chains are developed from literature. The model is tested in a case study of a supply chain involving Volvo Car Corporation and Volvo Logistics Corporation, comparing the use of newly developed, one-way packaging with the sustainability of returnable packaging. The model compares the environmental and economic impacts of two packaging systems in a specific supply chain. The criteria used in the model are (i) packaging fill rate, (ii) packaging material, (iii) transport, (iv) material handling, (v) waste handling and (vi) administration. In the case study, the one-way packaging resulted in fewer economic and environmental impacts, thereby indicating the importance for companies to question their packaging systems. The model has been tested on one component in a case study. It provides a comparison of the packaging choices included using comparative, but not absolute, figures for the economic and environmental impacts. Managers can use the model to compare packaging systems for component supply and determine the most sustainable packaging from environmental and economic perspectives. The case study indicated that the returnable packaging system commonly used in the automotive industry is not always preferable in terms of sustainability. The article fulfils the need to evaluate the impact of packaging systems on supply chain sustainability in terms of economic and environmental criteria.
Abstract Mechanical stresses from the shocks and vibrations to which air cargo is exposed during transport and handling at airports have been investigated. Field trials were carried out at Arlanda Airport, Stockholm, and John F. Kennedy Airport, New York. It was found that when products are transported in the airport area, they are exposed to much higher stresses than during actual flight. Especially severe conditions were registered during transport at John F. Kennedy Airport. Measured stresses are related to the ground and mode of driving within the airport area, as well as to location on the pallet wagon. Guidelines as regards design of realistic, simulating test programs for product and package design are reported. Future development possibilities and suggestions for further research within the area are discussed.
Abstract A field study was conducted on board a Boeing 747 Combi (freight and passenger) aircraft on the route Stockholm (Arlanda) via Oslo (Gardermoen) to New York (John F. Kennedy Airport) and return to Stockholm (Arlanda). Shock and vibration, acting on the cargo, during air transportation were measured and analysed. The study encompassed all phases of the flight, including taxiing, climb, cruise during both calm and turbulent conditions, descent and approach, landing including touchdown and taxiing to apron. The field data were analysed by conventional frequency analysis and modelling techniques. In order to generalize the results, flight recorder data from the field trial and from other flights are included. Guide-lines for the development of realistic, simulation test programs for product and package design are included.
In food packaging applications where low-density polyethylene (LDPE) film containing ?-tocopherol is used, the antioxidant may have a dual function, i.e. to protect the polymer from oxidative degradation during processing, and to delay the onset of oxidation of the packaged foodstuff during storage. Incorporation of high levels of ?-tocopherol into LDPE film was found to inhibit oxidation of a linoleic acid emulsion stored in contact with the film at 6°C. However, the presence of 360 ppm caused changes in mechanical properties and an increase in oxygen transmission. Levels as high as 3400 ppm ?-tocopherol also caused yellowing and reduction in crystallinity of the material. Thus, the use of high amounts of ?-tocopherol in LDPE, which might be needed in active packaging applications, requires careful consideration of the protective requirements for each specific food and the maintenance of the desired properties of the packaging material.