Flexible Packaging Industry Research Articles

The effect of solvent mixture on the properties of solvent cast polylactic acid (PLA) film

AbstractThe objective of this study was to investigate the effects of various solvents on the crystallinity and thermal expansion stability of PLA film. Three different PLA films were produced by the solvent casting technique; PLA in chloroform (PLA‐C), PLA in methylene chloride (PLA‐M), and PLA in methylene chloride: acetonitrile = 50: 50 (PLA‐MA). The PLA‐MA had higher % crystallinity, 46.15, than the PLA‐C, 24.03, and the PLA‐M, 14.25. With this increase in crystallinity, the PLA‐MA had improved thermal expansion stability as shown by very low accumulated dimensional changes at 20 to 100°C. Wide‐angle X‐ray diffraction identified multiple crystalline structures for the PLA‐MA. Film barrier properties were also measured. PLA‐MA had the lowest oxygen permeability. However, there was no significant difference in water vapor permeability among the three PLA films. The mechanical property tests revealed that the PLA‐C and PLA‐M were ductile while the PLA‐MA was brittle in behavior. The PLA‐MA was very hazy as compared with the PLA‐C and PLA‐M. This work has shown that the PLA‐MA had increased % crystallinity and, more importantly, it had improved thermal expansion stability which can be very beneficial for the flexible packaging industry. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Water vapor and oxygen-barrier performance of corn–zein coated polypropylene films

A novel corn–zein coating structure on polypropylene (PP) films was developed to examine its feasibility as an alternative water vapor and oxygen-barrier for flexible packaging industry. The barrier properties of the resulting films were evaluated as affected by coating formulation (solvent, corn–zein, plasticizer concentration and plasticizer type). Corn–zein with different amounts (5% and 15%) was dissolved in 70% and 95% aqueous ethanol solution at 50 °C, respectively. Solutions of corn–zein plasticized by polyethylene glycol (PEG) and glycerol (GLY) with various levels (20% and 50%) were applied on corona-discharged-treated PP by using solvent-casting method. The significant improvements in water vapor and oxygen-barrier properties of uncoated PP films were obtained with corn–zein coating. Water vapor permeability (WVP) of the coated films decreased significantly with increasing corn–zein concentration. The application of plasticized corn–zein coating on PP films showed nearly more than three order of reduction in oxygen permeability (OP). The high water vapor and oxygen-barriers were obtained for films coated with coating formulation consisting of higher amounts of corn–zein plasticized by GLY. The statistical analysis defined the key parameters of coating formulation that had major effect on the final properties of coated PP films as corn–zein, plasticizer concentration, and plasticizer type.

Prediction and experimental verification of bubble and processing characteristics in blown‐film extrusion

AbstractBlown‐film modeling is useful to the flexible packaging industry for predicting process and bubble characteristics, such as freeze line height (FLH), bubble diameter, and film thickness. The use of a suitable rheological equation to describe material properties is critical in simulating the blown‐film process. In this article, we present an improved rheological constitutive equation, which incorporates more realistic parameters of stress and deformation properties of the materials by combining the Hookean model with the Phan‐Thien Tanner (PTT) model. The proposed PTT–Hookean model is aimed at enhancing the viscoelastic behavior of the melt during biaxial stretching in the blown‐film extrusion. Predictions of the blown‐film bubble characteristics and FLH obtained with the PTT–Hookean model agreed well with the experimental data of this study and previous studies with different materials and different die geometries. The justification for combining the Hookean model with the PTT model in the blown‐film process is also reported here. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Empirical models for end-use properties prediction of LDPE: application in the flexible plastic packaging industry

The objective of this work is to develop empirical models to predict end use properties of low density polyethylene (LDPE) resins as functions of two intrinsic properties easily measured in the polymers industry. The most important properties for application in the flexible plastic packaging industry were evaluated experimentally for seven commercial polymer grades. Statistical correlation analysis was performed for all variables and used as the basis for proper choice of inputs to each model output. Intrinsic properties selected for resin characterization are fluidity index (FI), which is essentially an indirect measurement of viscosity and weight average molecular weight (MW), and density. In general, models developed are able to reproduce and predict experimental data within experimental accuracy and show that a significant number of end use properties improve as the MW and density increase. Optical properties are mainly determined by the polymer morphology.

An empirical study of the relationship between absorptive capacity and technology transfer effectiveness

This study investigates the relationship of Absorptive Capacity (AC) and its elements to Technology Transfer Effectiveness (TTE) in the flexible packaging industry in Thailand. The relationship of each AC element to each dimension of TTE is assessed. Findings are that TTE is related to all AC elements, but not all to the same degree. While all AC elements were found to have a positive correlation with two TTE dimensions, namely product and process performance and human resources capability, only two AC elements, namely the ability to assimilate and the ability to apply the new technology, showed a strong positive correlation to the TTE dimension of business performance. The findings of this study help academics and practitioners to have a clearer understanding of the different elements of AC and TTE, the impact of AC on TTE, and especially the correlation of each AC element to each TTE dimension.

Growth and Development of the Asian Flexible Packaging Industry

This paper provides an introduction to the flexible packaging industry in the Asian region. It deals with the area from Korea in the north to Indonesia in the south and across to India/Pakistan but largely excludes Japan due to the very different nature and dynamics of the Japanese market. The paper describes the economic structure and groupings in the region. It looks at the history and background of flexible packaging in Asia, the factors that influenced growth and describes the current state of the industry and future directions. Converting equipment trends are discussed along with general development trends. Some typical Asian packaging solutions will be highlighted to demonstrate the direction of the industry.

Practical Application of SPC in the Flexible Packaging Industry

Practical Application of SPC in the Flexible Packaging Industry

Strategic change in the European flexible packaging industry

This article analyses recent strategic changes in the European flexible packaging industry. It demonstrates that the different forces driving international industry competition can always be translated into requirements for stronger integration or stronger national responsiveness. The flexible packaging industry is primarily confronted with environmental requirements for high integration so as to capture economies of scope. Interviews conducted with managers of nine large firms, which recently went through significant restructuring demonstrates that most of these firms are now indeed emphasizing integration in their strategic posture, thus limiting their strategic vulnerability vis-a-vis environmental change.

Hydration of oxide films on aluminium and its relation to polymer adhesion

AbstractIn the flexible packaging industry, aluminium foil is used to fabricate metal–polymer complex systems without any prior surface treatment (e.g. anodic oxide, chemical conversion coating). The inevitable delay between foil rolling and subsequent application of the polymer, in this case polyethylene, allows ageing of the aluminium oxide to occur, which may significantly reduce the adhesion strength of the metal/polymer joint.To enable a better understanding of the ageing phenomena occurring and hence to improve the industrial control of the key parameters, controlled ageing of mini‐coils of a 1200 aluminium alloy has been performed in H2O and D2 atmospheres, with some material being subsequently stored under dry conditions. The resultant hydration of the surface oxide has been followed by XPS, SIMS and electrochemical impedence spectroscopy (EIS).The combination of XPS and EIS indicates that loosely bound physisorbed water, partly removed by dry storage, plays a key role in the adhesion strength of the metal/polymer joint. SIMS imaging of deuterium incorporated in the film as Al(OD)3 shows clearly the heterogeneous nature of the hydration process, with preferential sites being associated with iron‐rich intermetallic phases. For storage periods of >50 days, the formation of these friable bayerite islands predominates and will cause catastrophic loss of adhesion. For shorter periods, however, the loosely bound water plays a major role, and its reversible nature points to the possibility of at least partial recovery of the joint strength by dry storage of the foil prior to application of the polymer.

The implication of migration testing for the flexible packaging industry

The implication of migration testing for the flexible packaging industry

Cellophane — The deceptively versatile non-plastic

Although typically associated with the flexible packaging industry, Cellophane film is a highly versatile material which continues to find application in a wide range of industrial markets. There are over 100 different types and gauges of Cellophane film currently available, forend-uses ranging from twistwraps for chocolate confectionery to release agents for GRP plastic panelling. The versatility of this form of regenerated cellulose suggests that new end-uses will come to light as design engineers become more familiar with the performance and application potential of this unique material.

Toxicological Considerations in the Selection of Flexible Packaging Materials for Foodstuffs

High molecular weight polymers are the “backbone” of the flexible packaging industry, although a variety of papers, fabrics, and metallic foils are also employed. Almost without exception, high molecular weight polymers are physiologically inert and, therefore, pose no toxicological problems in themselves. However, monomers and low molecular weight fractions that may be incorporated in certain commercial polymers can be a source of concern, as can be other low molecular weight chemicals purposely added to commercial polymers, in some instances, to modify their processing or functioning characteristics. Conditions of use must also be considered when employing polymeric films (with or without additives) as the food contact components of packages. A polymer may be completely nontoxic and an adequate barrier to other package constituents when used to contain foodstuffs if the resultant package is subsequently stored at room temperature, under refrigeration, or frozen. However, when used as the inner ply of a boil-in pouch, a retortable pouch, or an oven bag, it must be determined that it is not subject to some degree of thermal breakdown or allows permeation of adhesive or ink components not approved for direct contact with food. Finally, if there is a requirement to sterilize packages before filling, as in aseptic packaging, the effect of the sterilizing medium on the packaging material must be fully understood.