On‐going solutions to environmental issues in plastic packaging

Recently, the consumption of polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC) resins as packaging materials has been declining in the face of various environmental problems they pose. To replace PVC containers, the use of PET bottles and A‐PET containers is on the increase, but PVDC resins are still in wide use as gas‐barrier materials. For gas‐barrier purposes, however, ethylene vinyl alcohol co‐polymer (EVOH) films, polyvinyl alcohol (PVA)‐coated polypropylene films, and MX nylon or silica‐ or alumina‐coated PET films are becoming mainstream. The weight reduction of plastic bottles is considered to play an important role in tackling the waste disposal problem. Recently, a new type of stretch‐blow moulding system has been developed, which is effective in reducing the weight of PET bottles. This system is called COSMOS (complete stretch‐blow moulding system) or the two‐blow system. COSMOS PET bottles are now used to hold carbonated drinks containing fruit juice or lactic acid. Copyright © 2001 John Wiley & Sons, Ltd.     

Investigation of antimony,cobalt, and acetaldehyde migration into the drinking water in Turkey

Polyethylene terephthalate (PET) is a widely used material for the packaging of drinking water. The development of this research arises from the demand of a popular Turkish drinking water company, which has reported odour problems in their PET bottled products. Acetaldehyde, cobalt, and antimony contents were determined in bottled water of different volumes (0.5, 1.5, and 5 L), PET bottles, plastic blue closures, and preform material by gas chromatography mass spectrometry (GC‐MS) and inductively coupled plasma mass spectrometry (ICP‐MS). Antimony, cobalt, and acetaldehyde migration into the drinking water (PET bottled) was tracked for every 2 months through a year. Migration of these compounds rose with increased storage time at 20°C. The highest amounts of migrated compounds were observed in 0.5 L (smallest) of PET bottles. All migration results were found to be under the migration limit at the end of storage period. In addition to these findings, nonintentionally added substances (NIASs) analyses were performed by headspace (HS)/GC‐MS. Odour‐active compounds were identified using the library database. Off‐odours in the drinking water were due to the migration of various compounds such as acetaldehyde and other NIASs from PET bottle into the drinking water. In addition, acetaldehyde amounts were ranged from 0 to 140 μg/L in all drinking waters, and some acetaldehyde values were above the taste threshold of 15 μg/L.     

PET 瓶装碳酸饮料货架期影响因素研究

目的研究影响碳酸饮料货架期的各种因素。方法以PET瓶装碳酸饮料为研究对象,分析了PET瓶的二氧化碳泄漏的途径,通过4类实验分析了温度、壁厚、二氧化碳阻隔剂、气含量等因素对其泄漏速度的影响。结果常温下瓶体是二氧化碳泄露的主要途径,降低仓储温度、增加瓶子壁厚,在PET料里添加二氧化碳阻隔剂以及增加气体含量都可以有效延长货架期,而高温下气体含量高的饮料的货架期可能更短。结论实验得到了不同仓储温度、瓶子壁厚、不同初始含气量以及添加二氧化碳阻隔剂与产品货架期的关系。     

高阻氧性PET果汁饮料瓶的研究发展趋势

论述了提高PET果汁饮料瓶阻氧性的意义和方法.介绍了不同共混法制取PET果汁饮料瓶的国内外研究现状,指出了提高PET果汁饮料瓶阻氧性研究的方向,有利于PET材料在果汁饮料包装领域的广泛应用.     

荧光照射下PET阻隔瓶对杀菌乳风味的保护研究

目的 研究分析添加质量分数为8%的阻光色油的PET瓶（简称阻光8%PET瓶）包装对杀菌乳风味物质组成和含量的影响,为杀菌乳保质期的延长提供数据支撑。方法 模拟超市货架光照情况,以纯PET瓶和阻光8%PET瓶包装做对比,分析不同贮存期杀菌乳感官风味指标变化及特征风味物质组成及含量变化。结果 相对纯PET瓶杀菌乳,阻光8%PET瓶杀菌乳,光照3、7 d后两样品关键感官特性指标（奶香气、奶腥味、异味强度）及整体喜好度平均值均表现出显著性差异（P<0.05）,阻光8%PET瓶杀菌乳的奶香气、整体喜好度评价均优于纯PET瓶杀菌乳的,奶腥味、异味强度均低于纯PET瓶杀菌乳的。经特征风味化合物分析,醛类化合物对杀菌乳异常风味贡献最大,酸类、酮类、醇类物质贡献较小。结论 阻光8%PET瓶包装能有效延缓光照31 d贮存期杀菌乳产品醛类物质的种类和含量的迅速增加,能一定程度减少部分酸类、酮类、醇类物质的增加,从而减少异常风味,提高产品的喜好度,可一定程度延长杀菌乳的货架期。     

Effects of weight reduction of packaging material on the mechanical performance of PET bottles for cooking oil

This study compares and evaluates the mechanical performance of two types of PET bottle of different nominal weights but identical design and filled with 900 ml vegetable cooking oil. The air in the headspace of all the bottles was replaced with liquid or gaseous nitrogen upon conclusion of the filling operation and immediately before capping. Two different closures, with an internal or external tamper‐evident feature, were used on the 20 g bottles. The 27 g bottle was closed exclusively with the closure fitted with an external seal. The 20 g PET bottles prior to capping were either flushed with gaseous nitrogen or pressurized with liquid nitrogen. The air contained in the headspace of the 27 g bottle was removed by injection of gaseous nitrogen only. Corrugated fibreboard cases containing 20 bottles each were submitted to a vibration test and all the components of the packaging system were subsequently evaluated with respect to important mechanical properties, such as stacking strength, drop impact strength and package integrity. The results show that the closure with external seal provided considerably better protection against leakage. Also tests conducted with stacks of five corrugated cases each and arranged onto two pallets placed one upon the other demonstrated that reducing total bottle weight by 26% is viable in terms of mechanical performance. On the other hand, the use of pressurized liquid nitrogen was found to be unnecessary. Copyright © 2000 John Wiley & Sons, Ltd.     

Influence of compositions of modified blends of polyamide/poly(vinyl alcohol) on the methanol/gasoline fuel barrier properties of polyethylene/modifiedblends of polyamide/poly(vinylalcohol) bottles

Polyamide (PA), poly(vinyl alcohol) (PVA) and the blends of PA and PVA were modified by a compatibilizer (CP) to make modified polyamide (MPA), modified PVA (MPVA) and modified PA/PVA (MPAPVA) blends through reactive extrusion. The MPVA and MPA hot-pressed sheets exhibit the best and worst methanol/gasoline fuel permeation resistance among these modified resins, which show much better methanol/gasoline fuel permeation resistance than pure PE resin. It is worth noting that the methanol/gasoline fuel permeation resistance of MPAPVA sheets improves consistently with their PVA contents. Similarly, after blending these barrier resins with PE, the methanol/gasoline fuel permeation resistance of the blended bottles improves to become significantly better than that of pure PE bottles. Further investigations found that the hydrocarbon components with 5 to 10 main-chain carbon atoms present in methanol/gasoline fuels were successfully blocked during the permeation tests. However, the order of barrier improvement of PE/MPA, PE/MPAPVA and PE/MPVA bottles does not completely correspond to the order of the barrier improvement of the base barrier resins before blending and blow-molding with PE. For instance, the PE/MPVA and PE/MPAPVA bottle series with a PVA/PA weight ratio of 4 : 1 exhibit poorer methanol/gasoline fuel permeation resistance than all the other PE/MPAPVA bottles, although the base MPVA and MPAPVA with a 4 : 1 PVA/PA weight ratio are associated with better permeation resistance than the other MPAPVA resins prepared in this study. These interesting phenomena were investigated in terms of the melt shear viscosities, chemical structure and morphology of the barrier resins present in their corresponding bottles.     

Determination of various constituent elements of polyethylene terephthalate bottles used for beverages in Japan

Polyethylene terephthalate (PET) bottles are some of the most commonly used containers for beverages. During the manufacturing process of PET resin in Japan, metallic catalysts such as Sb and Ge are widely used, with other metals or metallic compounds also being employed to improve the quality of PET bottles. However, few reports into the contents of such elements exist. Thus, we herein report the concentrations of 34 elements (ie, Li, B, Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Zr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, W, Pb, and U) in 16 samples of unused virgin PET bottles for beverages. The measurement was performed by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS), and these bottles were found to contain five main elements (ie, <0.5- to 50-mg/kg Ge, <1- to 26-mg/kg Ti, <0.1- to 279-mg/kg Sb, <10- to 48-mg/kg P, and <0.5- to 53-mg/kg Co) that were used as polymerisation catalysts, stabilisers, oxidation catalysts, and bluing agents. Furthermore, when these residual element concentrations in 21 commercial mineral-water PET bottles were determined, there was no significant difference from unused bottles.     

Studies on the development of a quick inertness test procedure for multi-use PET containers—sorption behaviour of bottle wall strips

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 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; 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 John Wiley & Sons, Ltd.     

Modifizierung organischer Konstruktionswerkstoffe für technische Anwendungen

Modification of Organic Engineering Materials for Technological Applications It is reported about experiments for synthesis of novel reactive, thermotropic, liquid‐crystalline polymers (LCPs) as well as about investigations concerning the use of these LCPs as a blend component for the production of modified polyamide and polyester fibres and their properties. These reactive LCPs are synthetically easy accessible p oly e ster i mid a nhydrides ( PEIA ) bearing lateral as well as terminal anhydride groups. The average number of anhydride groups is variable between 4 and 18. Molecular weights of 30 kg/mol up to 80 kg/mol could be obtained. During mixing of the reactive LC‐PEIAs with polyamide 6 [PA 6] or poly(ethylene terephthalate) [PET] in an extruder under melting conditions both components evidently react within some few minutes to form graft‐block‐copolymers containing on their backbone chains lateral and terminal polyamide respectively polyester blocks. These quickly occurring modification reactions are the base for the industrial application in form of a continuously arrangeable “reactive blending‐spinning‐drawing”‐process. Graft‐block‐copolymers synthesised by this way in the sense of “reactive blending” can be processed together with the corresponding adequate matrix material polyamide 6 or polyester into drawable filaments. After spinning and drawing under suitable conditions lc‐PEIA‐fibrils modified by molecules of the basic polymer with diameters of less than 500 nm are detectable in the resulting filaments. The desired “microphase distribution” of the PA‐modified respectively PET‐modified lc‐PEIA‐macromolecules as the reinforcing system components could be achieved. Moreover these graft‐block‐copolymers built by “reactive blending” in‐situ have a high thermodynamic compatibility because of their chemical similarity to the primary structure of the respective matrix materials resulting in a relatively high reinforcing effect. These both aspects as well as the proceeding orientation of the lc‐PEIA‐microphases by the filament drawing cause, though optimising processes are still remaining, a remarkable increase of the tensile strengths as well as clearly improved initial moduli at a simultaneously raised stretchability of the lc‐PEIA‐modified polyamide and polyester filaments. These effects could be achieved with PEIA‐amounts of lower than 5 percentages by weight .     

Effect of high‐pressure processing on the mechanical and barrier properties of selected packagings

This investigation focuses on the effect of high‐pressure processing (HPP) on possible changes of the mechanical properties and of the water vapour permeability of seven selected packaging materials. NOD 259 (PA‐PE), BB4L (Cryovac‐Grace packaging), PET/BOA/PE, PET/PVDC/PE, PA/SY, LDPE and EVA/PE were investigated (PET, polyester; PE, polyethylene; SY, surlyn; LDPE, low‐density polyethylene; EVA, polyethylene–vinyl acetate co‐polymer; BOA, biaxially oriented polyamide). These packaging materials were selected because of their interest to the food industry. All had an internal film of PE for food use. High‐pressure tests were realized at 10°C for 10 min at pressures of 200, 400 and 600 MPa, with water as a food‐simulating fluid. The depressurization rate was either rapid (pressure drop in <10s) or slow (20 MPa/min). Permeability to water vapour was realized using the NFF H 00 030–ASTM E96‐90 standard. Mechanical tests were carried out with a tensile testing machine (Lloyd LR5K), according to the NF 54‐102 standard. Maximal stress, rupture stress and strain at rupture were evaluated with non‐treated and treated samples. Obtained results showed that HPP minimally affects the mechanical strength of packaging material. The depressurization rate did not have any significant influence in our conditions. The barrier properties to water vapour were not significantly affected and were even slightly enhanced for LDPE, which is a packaging material commonly used for HPP applications and at least as a food contact material. Copyright © 2006 John Wiley & Sons, Ltd.     

高阻隔PET瓶的质量缺陷分析及处理对策

在介绍了高阻隔PET瓶的特点和常用生产工艺的基础上,详细论述了高阻隔PET瓶在成型过程中的常见质量缺陷产生的原因,并针对不同缺陷的成因提出了防范的措施.分析表明,实际生产中要提高产品质量需要加强成型工艺条件的控制,必要时要改变材料配方.     

Quality of orange juice in barrier packaging material

The vitamin C content and the colour of orange juice made from concentrate were measured during 9 months of storage at 20°C either under artificial light or in darkness. The packaging materials used were glass, standard monolayer polyethylene terephthalate (PET) and multilayer PET (PET/nylon and oxygen scavenger/PET) containers. In this experiment, all bottles were sealed with aluminium foil in order to avoid any cap effect. The results showed that in plastic packaging materials, the loss of vitamin C was related to the oxygen permeability, and that glass provided the best preservation of ascorbic acid. No statistical difference (p < 0.05) was revealed between the vitamin C content in the juice stored under artificial light or in darkness, whatever the packaging used. The modification of colour was studied with the L, a* and b* values during storage at 20°C under artificial light. L and b* decreased, revealing a reduction of lightness and yellow colour of the juice, whereas a* increased, due to the formation of brown pigments. This change in colour was partly related to the oxygen permeability of the packaging used. The losses of aroma compounds by permeation through the bottle (PET) and the cap (high‐density polyethylene, HDPE) have also been investigated. The results showed that permeation mainly took place through the cap. The use of a multilayer cap [HDPE with internal barrier layer of low‐density polyethylene (LDPE)/EvOH/LDPE] considerably limited the permeation of the aroma compounds studied, whatever the PET bottle used. Copyright © 2007 John Wiley & Sons, Ltd.     

吸氧性PET果汁饮料瓶的制备及性能研究

将吸氧剂与聚对苯二甲酸乙二醇酯(PET)共混制得吸氧性PET橙汁饮料瓶。利用扫描电子显微镜、容器透氧仪对共混材料的结构与性能进行测定;利用高效液相色谱和色差仪对瓶装橙汁的质量进行检测。结果表明,吸氧剂能有效提高PET瓶的阻氧性能,减缓橙汁中维生素C的氧化速度,保证其色泽鲜亮,口感纯正。     

Influence of Material Moisture on the Tribocharging Process of Plastic Granules

The control of the triboelectrification factors is the key for a successful application of electrostatic separation to the recycling of mixed plastics waste. This article focuses on the influence of material moisture on the tribocharging process of three granular materials: polyamide (PA), polyvinyl chloride (PVC), and polyethylene terephthalate (PET).

Different values of moisture content were obtained by immersing the material in water or drying it in a laboratory oven. Afterward, the granular material was tribocharged on the tray of a vibratory feeder and the accumulated charge was measured by an electrometer.

The maximum charge/mass ratio was obtained for the three plastic materials at different values of moisture content: 0.27% for PA, 0.12% for PET 0.1% for PVC. Series of 5 consecutive tribocharging experiments performed on the same sample, show that the first contributes with the greater amount of granules charge while the other four only slightly increment this value. The graphical representation of the evolution of the charge/mass ratio versus number of tribocharging experiment conducts to the conclusion that: i) the charge of the granules tends to saturate; ii) it is useless to excessively increase the duration of the tribocharging process.     

Simulation of the Decontamination Efficiency of PET Recycling Processes based on Solid‐state Polycondensation

The recollection rates for postconsumer poly(ethylene terephthalate) (PET) bottles and the recycling capacities are increasing year by year. The postconsumer PET bottles were recycled either to fibres or to new packaging applications. For packaging applications, the so‐called super‐clean recycling technologies are applied to decontaminate the postconsumer PET pellets. Most of these processes are based on solid‐state polycondensation processes. Because experimental determination of the cleaning efficiency is a time‐consuming and expensive procedure, it would be useful to predict the cleaning efficiencies, e.g. for process development and optimization. Within this study, the decontamination kinetics of a PET super‐clean recycling process based on solid‐state polycondensation was determined. From the decontamination kinetics, the diffusion coefficients were calculated. By use of the diffusion coefficients, the decontamination kinetics was simulated using migration modelling approaches for spherical pellets. The result of this study shows that the decontamination of PET pellets in solid‐state polycondensation processes follows Fickian laws. The diffusion coefficients of the investigated migrants are not influenced by vacuum or inert gas process conditions. The diffusion equations used in commercially available software packages for migration calculation can be used for the simulation of the decontamination efficiencies of PET recycling processes. Copyright © 2012 John Wiley & Sons, Ltd.     

涂层技术制备高阻隔性PET瓶的应用研究

对聚偏二氯乙烯、改性聚乙稀醇和环氧-胺等有机涂层材料及氧化硅、类金刚石等无机涂层材料在PET瓶上的应用工艺、阻隔性能及其在国内外市场的研究进展进行了综述,指出高阻隔PET瓶目前仅处于小规模的试用阶段,若要成功实现从玻璃瓶到PET塑料瓶的转化,不仅需要提高PET材料的阻隔性能,还应保证其具有较高的透明性、可回收性、技术易操作性及实用性等。     

Permeation of Mineral Oil Components from Cardboard Packaging Materials through Polymer Films

Mineral oil migration from cardboard packaging into foodstuffs is recognized as a serious problem for the consumers. Within this study, a fast automated method for the determination of mineral oil permeation through barrier films was developed. The method is using 15 defined standard substances representing mineral oil chemistry instead of complex mineral oil mixtures. The developed method can be used for the evaluation of the barrier properties for polymer films regarding mineral oil components from paper and cardboard packaging materials. For all investigated permeants and polymer films, the logarithm of the permeation rates and the logarithm of the vapour pressure result in a linear correlation. The correlation can be used to compare the permeation properties of different barrier films. From the results of this study, it can be concluded that 12 µm oriented polyethylene terephthalate or 15 µm oriented polyamide are effective barriers towards mineral oil components. The barrier effect of pure polyolefin films is negligibly poor because the permeation is too fast and the lag time is in the range of a few hours at 40°C. As a consequence, the migration of mineral oil components from cardboard can be significantly reduced if inner layers of good barrier materials such as polyethylene terephthalate or polyamide are used. Copyright © 2012 John Wiley & Sons, Ltd.     

Oxygen permeability at high temperatures and relative humidities

It is a well-known fact that the permeability of polymer materials increases as the temperature increases. As the temperature drops to its original level, the permeability in many instances does the same. When packages are processed in an autoclave, the material will be exposed to both high temperature and high relative humidity. This can strongly affect the barrier of some materials, e.g. ethylene vinyl alcohol (EVOH) and polyamide (PA), because the water will act as a plasticizer. A current project is now studying the permeability of different materials after sterilization. The aim of the project is to determine the permeability of different materials during sterilization at autoclave conditions and during storage. Factors that can reduce the negative effect on the barrier are also examined.     

Lateral deformation of plastic bottles: experiments,simulations and prevention

Mass reduction of plastic bottles containing non-carbonated liquids calls for advanced design approaches. Weight reduction of bottles consequently influences the mechanical performance of the bottle. This performance involves top load, vacuum and impact resistance. The present paper studies the lateral deformation of a bottle due to an internal vacuum. Similar studies have been carried out before, but until now the allowable deformation has never been related to the initial headspace of the bottle. If a bottle design is able to compensate for a potential vacuum in an aesthetic manner, then panelling will not occur. Changing the vacuum resistance of a bottle will result in a different top load. Current computational techniques enhance our understanding of the problem and provide tools to achieve solutions to it. © 1998 John Wiley & Sons, Ltd.