The Clear Choice over Metal and Glass
Better materials and designs are allowing lightweight plastics to find their way into more durable packaging
Previous Article Next Article
By Nancy D. Lamontagne
The Klear Can, made from clarified polypropylene, is targeted for direct competition with traditional metal cans (photo courtesy of Milliken).
Lightweighting and sustainability have long been trends in packaging, but now, as companies develop new innovations, they must think of the product’s entire life cycle. Clear plastic is working its way into food applications that traditionally have used glass or metal, where it can offer both environmental and aesthetic benefits. Novel clarifiers, processing techniques, and closure technologies mean that plastic containers look much like glass on store shelves. In addition, the demand for lighter packaging is driving the development of new technologies and analysis techniques that can ensure that performance isn’t compromised, even when less material is used.
A Holistic View
Amcor Rigid Plastics supplies consumer-driven rigid plastic packaging for the food, beverage, pharmaceutical, and personal/homecare industries. Michael Hodges, director of communications at the company, says that sustainable packaging continues to be a focus for both the company and the packaging industry.
Rather than looking at only one aspect of sustainability, Amcor takes a holistic view of how each of its products affects the environment. “Sustainability is a factor in everything we do, from the time we start designing a product until our customers put it on the store shelf,” he says. “We want to ensure each package we produce uses resources in the most effective and efficient manner possible—that’s how we define responsible packaging.”
The trend toward lightweighting is strongly linked with making packaging sustainable, but Hodges points out that there is a point where a container becomes so thin that barrier materials must be added. Thus the company likes to use the term “rightweighting” when designing packaging.
An increase in preservative-free foods and beverages as well as pharmaceuticals is increasing the demand for packaging with greater barrier protection. However, this doesn’t simply mean adding a barrier to existing packaging. “When adding in the barrier, we have to look at it from a sustainability standpoint,” Hodges explains. “We have to figure out the right barrier, so that the packaging doesn’t become a problem in the recycling stream later.”
Amcor has a sustainability group that helps with life-cycle analyses for any new bottles being designed and works in concert with FEA engineers and product engineers to perform shelf-life studies to ensure product resilience. “We want to be sure that we always protect the brand, and that we always protect the product that is going into those bottles,” Hodges says.
Enlightening Concepts
Amcor recently introduced what it says is the industry’s lightest heat-set PET container, which received a beverage award in the WorldStar 2015 Packaging Awards Competition. The 500-mL sports drink bottle combines Amcor’s Ergo technology (to improve the feel of the bottle and absorb some of the vacuum) with the company’s vacuum-absorbing base technology.
New wide-mouth jars from Amcor accept a metal lug closure and are a glass-replacement option for pasta sauces and other foods (photo courtesy of Amcor).
Weighing just 22 grams, the new bottle is approximately 30% lighter than a standard 500-mL heat-set PET container, which typically weighs about 34 grams. The reduction in material reduces life cycle energy and emissions. According to Amcor, the new bottle cuts greenhouse gas emissions by 26%, energy use by 23%, water consumption by 24%, and the amount of waste that could potentially end up in a landfill by 26%. The new product was launched in Central America with future plans for distribution throughout Latin America.
Another new product from Amcor is a heat-set wide-mouth PET jar designed to replace glass jars that hold salsas, jams and jellies, and pasta sauces. The new jars are unique in that they use the
A-PEX63™ system technology to accept a metal lug closure. The A-PEX63 system ensures sealing integrity, meets the industry average for ease of opening, and features a functional “pop” tamper-evident indicator button. The containers are hot-fillable up to 96°C and available with Amcor’s Powerflex™ vacuum-absorbing base, the company adds.
Compared to a 330-gram glass container, the 51-gram PET container reduces material mass per jar by 85%. This lowers transportation costs and allows shipments of 30% more product, by weight, per truck.
Amcor is continuing to develop new ways to meet customer demand for authentic packaging, such as technology that would allow a cork to be inserted into a plastic wine bottle, and swing top closures that can be used with plastic bottles.
Glass Replacement
Europe-based APPE, which designs and manufactures rigid PET packaging for a variety of markets, is also finding new ways to replace glass with plastic. APPE’s Kinza Sutton explains that shatterproof packaging not only appeals to food manufacturers, retailers, and consumers, but because PET is up to 85% lighter than glass, it can reduce costs in the logistical chain and lessen the carbon footprint significantly.
“It is estimated that a PET plastic jar has half of the carbon footprint of an equivalent glass jar by the time it reaches the entrance of the filling line,” Sutton says. “This is key to retailers and brands actively seeking to reduce their carbon footprint.”
For manufacturers, using shatterproof containers increases safety in the filling lines and during transport and also avoids costly product recalls. Plastic jars and bottles take up less room than a glass equivalent because their walls are much thinner and require less secondary packaging, meaning more can fit on a pallet, truck, or shelf—which further reduces costs and environmental impact.
However, there are some things to keep in mind when replacing glass with plastics. For example, some foods are sensitive to oxygen, and depending on the shelf-life requirements, may require a barrier to protect against oxygen ingress. Also, if containers are hot-filled and/or pasteurized, a special packaging plastic and/or design is needed to cope with the temperature demands. “The challenge is to make a container that will withstand filling with hot contents and/or pasteurization, and not deform when cooling,” says Sutton.
APPE recently added a set of five new round jars to its ThermaLite line. The new 100% PET jars are designed to replace glass packaging and can be hot- or cold-filled at temperatures up to 95°C and then pasteurized using most methods. The jar’s clarity provides a clear view of the contents, and their metal twist-off cap is easy to open and reclose, the company says.
APPE recently added a set of five round PET jar designs to its ThermaLite line, as lighter-weight alternatives to glass jars (photo courtesy of APPE).
APPE’s ThermaLite jars are made using a “specialist” PET resin (the company says it’s based on an APPE-designed, patent-pending formulation) and a modified manufacturing process makes the PET stronger and more heat resistant.
The jar’s series of ribs provide structural strength, enable it to maintain shape during hot filling, and help to resist container deformation when the contents are cooled and the vacuum is formed. The ribs spaced along the walls of the jar can be easily covered with a label without detracting from the aesthetics of the finished container. The jar’s base is designed to retract into the jar to absorb some of the vacuum.
APPE says it has several customers for the ThermaLite jars, which are currently used to package pickled vegetables, relishes, and pasta sauces. Shelf-life trials are in process across Europe for a wide variety of applications, and the company anticipates that the demand will greatly increase over the next few years. “APPE continues to actively promote both glass replacement and the ThermaLite jar,” Sutton says, adding that the company’s “R&D center is looking at issues such as inclusion of recycled PET and development of other shapes and sizes.”
Adding Clarity
Cristina Acevedo, global product line manager for the plastics additives business of Milliken & Company, is seeing more demand for clear parts used for food packaging, as well as improved clarity in those parts. “For example, yogurt container manufacturers previously made containers that were opaque, but now want to showcase their product in clear containers,” she says.
Milliken’s Millad NX 8000 additive improves the clarity of polypropylene (PP), allowing containers made from this material to better showcase the freshness and quality of the food. NX 8000-clarified PP can be hot-filled and microwaved and is fully recyclable. According to the company, PP also brings the advantages of consuming less energy during production than other plastic materials and producing lower carbon dioxide emissions than other commonly used transparent plastics in food and beverage packaging, such as PET and polystyrene.
Since PP is one of the lowest-density plastics, it provides an 18% weight reduction in trays compared to PET, and a higher number of parts can be generated with the same weight of material. For example, Acevedo says that thermoformers can produce 263 flat beverage lids with 1 kg of PP, but could only make 216 lids with 1 kg of PET. PP also has a lower cost per volume compared to PET and polystyrene.
The Klear Can from Milacron is made of PP clarified with Milliken’s Millad NX 8000 additives. Consumers can clearly see the foods in the container, which features a metal lid. (Photo courtesy of Milliken.)
Milacron LLC recently introduced the Klear Can, which is made from two layers of PP resin clarified with Millad NX 8000 additives. This transparent alternative to traditional metal food cans reportedly is compatible with the existing downstream canning infrastructure and has the same lids found on metal cans. Moreover, consumers can easily view the quality and freshness of fruit, vegetables, and other foods through the clear container.
The Klear Can includes a proprietary false foot with a panel inside that flexes to accommodate stress so that the can maintains its round shape. The stackable cans resist dents and other handling damage common with metal cans, thanks to PP’s flexibility. They can be recycled with already-established systems and are 40-50% lighter than metal cans of the same size, helping reduce transportation costs, fuel usage, and carbon emissions.
An ethylene-vinyl alcohol copolymer (EVOH) barrier between the two PP layers allows for a two-year product shelf life, the manufacturers report. It’s also possible to tint the material or enhance the Klear Can with in-mold labeling.
Milliken makes other additives that improve polyolefin aesthetics, physical properties, processing efficiency, and sustainability. The company’s Hyperform HPN-20E nucleating agent allows downgauging or extending shelf life
in polyethylene blown films in cereal bags while enhancing aesthetics, the company says. And the Hyperform HPN-600ei nucleating agent is used in thermoformed food packaging to improve warpage control, cycle times, and an application’s stiffness-impact balance.
Using Science to Prevent Failure
Preventing flexible packaging failure is becoming more important, with today’s trends toward lighter, thinner, less-expensive packaging. In the food industry, any puncture or tear could lead to spoilage, and for medical applications, a break in the packaging could compromise sterility and require the product to be discarded.
Henk Blom, director of technical services at Rollprint Packaging Products, Inc. is working to uncover information that would lead to a more scientific way of designing flexible packaging, using just the right amount of material for the application. Today, many companies use trial and error to design flexible packaging materials that will withstand product distribution, often having to go back and make packaging thicker if holes or tears appear during shipping tests of the final product. Such approaches to durability testing and product design are costly and time consuming.
Taber Industries’ Linear Abraser allows users to apply a specified weight on a pin that scratches back and forth on film test samples. Researchers have used this instrument to gain information about the abrasion properties of flexible packaging materials. (Photo courtesy of Rollprint Packaging Products, Inc.)
“It would benefit the entire industry if we could design a package that isn’t over-engineered or under-engineered to the point that it fails, and do that intelligently with scientific principles,” Blom explains.
Blom began his work by studying the abrasion properties of monolayer materials with different thicknesses using a Taber Industries Linear Abraser. This instrument allows the user to apply a specific weight on a pin that scratches back and forth on the material. Blom looked at the effects of applied weight and film thickness on how many cycles it took for the pin to rub through the plastic. By analyzing this data, he was able to develop an equation that provides an abrasion coefficient:
He has since begun testing multilayer structures to determine whether the performance of a two-layer structure is the same as that of the two individual materials. Audiences have been interested in his work, which he has presented at several conferences, and he has received materials from several companies for testing. “It is recognized in the industry that we don’t know how to predict packaging material failure as well as we should,” he says.
Next, he would like to collect basic mechanical and molecular-level properties for the materials he has tested to see if he can derive a second equation that relates those fundamental properties to the material’s abrasion coefficients. This second equation could allow companies such as resin manufactures to understand how to tweak material properties to achieve better abrasion resistance.
“There are a whole series of equations that could be derived or empirically created to describe not only abrasion resistance, but also puncture and flex-crack resistance,” Blom says. “Ultimately, I would like to be able to work with a customer who has a specific set of requirements and be able to design the ideal material structure for the application, with neither too much nor too little material.”
Automatic Process Control
Agr International, Inc. offers products and services designed to meet the quality assurance needs of the beverage and packaging industries. Agr’s newest offerings reportedly can help manufacturers meet the increasing demand for lightweight PET bottles without
sacrificing quality.
With today’s lightweight bottles, it’s even more important that material is distributed correctly during molding. Six years ago, Agr introduced the Process Pilot®blow-molder management system in conjunction with the Pilot Profiler® material distribution measurement system.
The Process Pilot system precisely controls and maintains material distribution to a specified thickness to within ~0.01 mm. The system uses infrared light to precisely measure the thickness of material in multiple locations, from just below the support ring to right above the gate area. Continuous average measurements from 150 bottles are used to determine which blow-molder controls will be automatically adjusted to maintain the specified material distribution.
“It’s like the cruise control on the car; however, instead of just controlling one thing like the gas pedal, we are controlling the total oven power, the individual lamp value in the ovens, the pre-blow pressure, the pre-blow start, and the preform temperature set point—and we can control them all simultaneously,” explains Georg Wolfe, chief technical officer at Agr. “We’re able to lock in the material distribution that the process engineer really wants and keep it that way [across the] environmental variations that occur around the blow molder.”
About 250 systems from the Process Pilot family are in the field. Wolfe says the systems offer reasonable payback because of additional lightweighting savings and energy reductions—as well as increased uptimes on productions lines, especially downstream where a lightweighted bottle that doesn’t blow correctly could jam the labeler or filler.
The Process Pilot automated blow-molder management system includes the Pilot Profiler, which offers real-time measurement feedback during PET container production about every container produced (photo courtesy of Agr International, Inc.).
The company says it’s now in the process of commercializing a complementary technology called CrystalView™. It automatically optimizes the re-heat stretch blow-molding process, based on information from extensive studies on the relationship between blow-molding temperature and crystallinity conducted by Wolfe and his team. For cold-mold processes, CrystalView automatically controls polymer orientation at the blow molder by detecting the very edge of where the process gets too cold and pearlescence begins to form in the feet of the bottle. For hot-mold processes, CrystalView allows molding at a temperature just below the point where haze is created.
Using CrystalView in a closed loop simultaneously with Process Pilot provides automatic, continuous management of both material distribution and crystallinity. The system uses cameras, special lighting, and sophisticated algorithms to detect pearlescence or haze before it would be visible to an operator, allowing blow molding at the optimal temperature before pearlescence or haze occurs. Wolfe adds that this combination brings immediate payback, especially for carbonated soft drink bottles, because manufacturers can drop the oven temperature a few degrees.
“With CrystalView, not only do you get the best material properties out of the bottle and the best orientation/crystallinity out of the design, but you also get the best quality performance out of the bottle,” says Wolfe. “Everything gets maximized when the bottle is stretched optimally—burst pressure, volume expansion, time to stress crack, top load, shelf-life characteristics, and dimensional stability.”
Agr says it will soon begin field testing CrystalView and expects that it will be commercially available by the fourth quarter of 2015. Customers who have Process Pilot will be able to add CrystalView to their system.
The Clear Choice over Metal and Glass
Better materials and designs are allowing lightweight plastics to find their way into more durable packaging
Previous Article Next Article
By Nancy D. Lamontagne
The Klear Can, made from clarified polypropylene, is targeted for direct competition with traditional metal cans (photo courtesy of Milliken).
Lightweighting and sustainability have long been trends in packaging, but now, as companies develop new innovations, they must think of the product’s entire life cycle. Clear plastic is working its way into food applications that traditionally have used glass or metal, where it can offer both environmental and aesthetic benefits. Novel clarifiers, processing techniques, and closure technologies mean that plastic containers look much like glass on store shelves. In addition, the demand for lighter packaging is driving the development of new technologies and analysis techniques that can ensure that performance isn’t compromised, even when less material is used.
A Holistic View
Amcor Rigid Plastics supplies consumer-driven rigid plastic packaging for the food, beverage, pharmaceutical, and personal/homecare industries. Michael Hodges, director of communications at the company, says that sustainable packaging continues to be a focus for both the company and the packaging industry.
Rather than looking at only one aspect of sustainability, Amcor takes a holistic view of how each of its products affects the environment. “Sustainability is a factor in everything we do, from the time we start designing a product until our customers put it on the store shelf,” he says. “We want to ensure each package we produce uses resources in the most effective and efficient manner possible—that’s how we define responsible packaging.”
The trend toward lightweighting is strongly linked with making packaging sustainable, but Hodges points out that there is a point where a container becomes so thin that barrier materials must be added. Thus the company likes to use the term “rightweighting” when designing packaging.
An increase in preservative-free foods and beverages as well as pharmaceuticals is increasing the demand for packaging with greater barrier protection. However, this doesn’t simply mean adding a barrier to existing packaging. “When adding in the barrier, we have to look at it from a sustainability standpoint,” Hodges explains. “We have to figure out the right barrier, so that the packaging doesn’t become a problem in the recycling stream later.”
Amcor has a sustainability group that helps with life-cycle analyses for any new bottles being designed and works in concert with FEA engineers and product engineers to perform shelf-life studies to ensure product resilience. “We want to be sure that we always protect the brand, and that we always protect the product that is going into those bottles,” Hodges says.
Enlightening Concepts
Amcor recently introduced what it says is the industry’s lightest heat-set PET container, which received a beverage award in the WorldStar 2015 Packaging Awards Competition. The 500-mL sports drink bottle combines Amcor’s Ergo technology (to improve the feel of the bottle and absorb some of the vacuum) with the company’s vacuum-absorbing base technology.
New wide-mouth jars from Amcor accept a metal lug closure and are a glass-replacement option for pasta sauces and other foods (photo courtesy of Amcor).
Weighing just 22 grams, the new bottle is approximately 30% lighter than a standard 500-mL heat-set PET container, which typically weighs about 34 grams. The reduction in material reduces life cycle energy and emissions. According to Amcor, the new bottle cuts greenhouse gas emissions by 26%, energy use by 23%, water consumption by 24%, and the amount of waste that could potentially end up in a landfill by 26%. The new product was launched in Central America with future plans for distribution throughout Latin America.
Another new product from Amcor is a heat-set wide-mouth PET jar designed to replace glass jars that hold salsas, jams and jellies, and pasta sauces. The new jars are unique in that they use the
A-PEX63™ system technology to accept a metal lug closure. The A-PEX63 system ensures sealing integrity, meets the industry average for ease of opening, and features a functional “pop” tamper-evident indicator button. The containers are hot-fillable up to 96°C and available with Amcor’s Powerflex™ vacuum-absorbing base, the company adds.
Compared to a 330-gram glass container, the 51-gram PET container reduces material mass per jar by 85%. This lowers transportation costs and allows shipments of 30% more product, by weight, per truck.
Amcor is continuing to develop new ways to meet customer demand for authentic packaging, such as technology that would allow a cork to be inserted into a plastic wine bottle, and swing top closures that can be used with plastic bottles.
Glass Replacement
Europe-based APPE, which designs and manufactures rigid PET packaging for a variety of markets, is also finding new ways to replace glass with plastic. APPE’s Kinza Sutton explains that shatterproof packaging not only appeals to food manufacturers, retailers, and consumers, but because PET is up to 85% lighter than glass, it can reduce costs in the logistical chain and lessen the carbon footprint significantly.
“It is estimated that a PET plastic jar has half of the carbon footprint of an equivalent glass jar by the time it reaches the entrance of the filling line,” Sutton says. “This is key to retailers and brands actively seeking to reduce their carbon footprint.”
For manufacturers, using shatterproof containers increases safety in the filling lines and during transport and also avoids costly product recalls. Plastic jars and bottles take up less room than a glass equivalent because their walls are much thinner and require less secondary packaging, meaning more can fit on a pallet, truck, or shelf—which further reduces costs and environmental impact.
However, there are some things to keep in mind when replacing glass with plastics. For example, some foods are sensitive to oxygen, and depending on the shelf-life requirements, may require a barrier to protect against oxygen ingress. Also, if containers are hot-filled and/or pasteurized, a special packaging plastic and/or design is needed to cope with the temperature demands. “The challenge is to make a container that will withstand filling with hot contents and/or pasteurization, and not deform when cooling,” says Sutton.
APPE recently added a set of five new round jars to its ThermaLite line. The new 100% PET jars are designed to replace glass packaging and can be hot- or cold-filled at temperatures up to 95°C and then pasteurized using most methods. The jar’s clarity provides a clear view of the contents, and their metal twist-off cap is easy to open and reclose, the company says.
APPE recently added a set of five round PET jar designs to its ThermaLite line, as lighter-weight alternatives to glass jars (photo courtesy of APPE).
APPE’s ThermaLite jars are made using a “specialist” PET resin (the company says it’s based on an APPE-designed, patent-pending formulation) and a modified manufacturing process makes the PET stronger and more heat resistant.
The jar’s series of ribs provide structural strength, enable it to maintain shape during hot filling, and help to resist container deformation when the contents are cooled and the vacuum is formed. The ribs spaced along the walls of the jar can be easily covered with a label without detracting from the aesthetics of the finished container. The jar’s base is designed to retract into the jar to absorb some of the vacuum.
APPE says it has several customers for the ThermaLite jars, which are currently used to package pickled vegetables, relishes, and pasta sauces. Shelf-life trials are in process across Europe for a wide variety of applications, and the company anticipates that the demand will greatly increase over the next few years. “APPE continues to actively promote both glass replacement and the ThermaLite jar,” Sutton says, adding that the company’s “R&D center is looking at issues such as inclusion of recycled PET and development of other shapes and sizes.”
Adding Clarity
Cristina Acevedo, global product line manager for the plastics additives business of Milliken & Company, is seeing more demand for clear parts used for food packaging, as well as improved clarity in those parts. “For example, yogurt container manufacturers previously made containers that were opaque, but now want to showcase their product in clear containers,” she says.
Milliken’s Millad NX 8000 additive improves the clarity of polypropylene (PP), allowing containers made from this material to better showcase the freshness and quality of the food. NX 8000-clarified PP can be hot-filled and microwaved and is fully recyclable. According to the company, PP also brings the advantages of consuming less energy during production than other plastic materials and producing lower carbon dioxide emissions than other commonly used transparent plastics in food and beverage packaging, such as PET and polystyrene.
Since PP is one of the lowest-density plastics, it provides an 18% weight reduction in trays compared to PET, and a higher number of parts can be generated with the same weight of material. For example, Acevedo says that thermoformers can produce 263 flat beverage lids with 1 kg of PP, but could only make 216 lids with 1 kg of PET. PP also has a lower cost per volume compared to PET and polystyrene.
The Klear Can from Milacron is made of PP clarified with Milliken’s Millad NX 8000 additives. Consumers can clearly see the foods in the container, which features a metal lid. (Photo courtesy of Milliken.)
Milacron LLC recently introduced the Klear Can, which is made from two layers of PP resin clarified with Millad NX 8000 additives. This transparent alternative to traditional metal food cans reportedly is compatible with the existing downstream canning infrastructure and has the same lids found on metal cans. Moreover, consumers can easily view the quality and freshness of fruit, vegetables, and other foods through the clear container.
The Klear Can includes a proprietary false foot with a panel inside that flexes to accommodate stress so that the can maintains its round shape. The stackable cans resist dents and other handling damage common with metal cans, thanks to PP’s flexibility. They can be recycled with already-established systems and are 40-50% lighter than metal cans of the same size, helping reduce transportation costs, fuel usage, and carbon emissions.
An ethylene-vinyl alcohol copolymer (EVOH) barrier between the two PP layers allows for a two-year product shelf life, the manufacturers report. It’s also possible to tint the material or enhance the Klear Can with in-mold labeling.
Milliken makes other additives that improve polyolefin aesthetics, physical properties, processing efficiency, and sustainability. The company’s Hyperform HPN-20E nucleating agent allows downgauging or extending shelf life
in polyethylene blown films in cereal bags while enhancing aesthetics, the company says. And the Hyperform HPN-600ei nucleating agent is used in thermoformed food packaging to improve warpage control, cycle times, and an application’s stiffness-impact balance.
Using Science to Prevent Failure
Preventing flexible packaging failure is becoming more important, with today’s trends toward lighter, thinner, less-expensive packaging. In the food industry, any puncture or tear could lead to spoilage, and for medical applications, a break in the packaging could compromise sterility and require the product to be discarded.
Henk Blom, director of technical services at Rollprint Packaging Products, Inc. is working to uncover information that would lead to a more scientific way of designing flexible packaging, using just the right amount of material for the application. Today, many companies use trial and error to design flexible packaging materials that will withstand product distribution, often having to go back and make packaging thicker if holes or tears appear during shipping tests of the final product. Such approaches to durability testing and product design are costly and time consuming.
Taber Industries’ Linear Abraser allows users to apply a specified weight on a pin that scratches back and forth on film test samples. Researchers have used this instrument to gain information about the abrasion properties of flexible packaging materials. (Photo courtesy of Rollprint Packaging Products, Inc.)
“It would benefit the entire industry if we could design a package that isn’t over-engineered or under-engineered to the point that it fails, and do that intelligently with scientific principles,” Blom explains.
Blom began his work by studying the abrasion properties of monolayer materials with different thicknesses using a Taber Industries Linear Abraser. This instrument allows the user to apply a specific weight on a pin that scratches back and forth on the material. Blom looked at the effects of applied weight and film thickness on how many cycles it took for the pin to rub through the plastic. By analyzing this data, he was able to develop an equation that provides an abrasion coefficient:
He has since begun testing multilayer structures to determine whether the performance of a two-layer structure is the same as that of the two individual materials. Audiences have been interested in his work, which he has presented at several conferences, and he has received materials from several companies for testing. “It is recognized in the industry that we don’t know how to predict packaging material failure as well as we should,” he says.
Next, he would like to collect basic mechanical and molecular-level properties for the materials he has tested to see if he can derive a second equation that relates those fundamental properties to the material’s abrasion coefficients. This second equation could allow companies such as resin manufactures to understand how to tweak material properties to achieve better abrasion resistance.
“There are a whole series of equations that could be derived or empirically created to describe not only abrasion resistance, but also puncture and flex-crack resistance,” Blom says. “Ultimately, I would like to be able to work with a customer who has a specific set of requirements and be able to design the ideal material structure for the application, with neither too much nor too little material.”
Automatic Process Control
Agr International, Inc. offers products and services designed to meet the quality assurance needs of the beverage and packaging industries. Agr’s newest offerings reportedly can help manufacturers meet the increasing demand for lightweight PET bottles without
sacrificing quality.
With today’s lightweight bottles, it’s even more important that material is distributed correctly during molding. Six years ago, Agr introduced the Process Pilot®blow-molder management system in conjunction with the Pilot Profiler® material distribution measurement system.
The Process Pilot system precisely controls and maintains material distribution to a specified thickness to within ~0.01 mm. The system uses infrared light to precisely measure the thickness of material in multiple locations, from just below the support ring to right above the gate area. Continuous average measurements from 150 bottles are used to determine which blow-molder controls will be automatically adjusted to maintain the specified material distribution.
“It’s like the cruise control on the car; however, instead of just controlling one thing like the gas pedal, we are controlling the total oven power, the individual lamp value in the ovens, the pre-blow pressure, the pre-blow start, and the preform temperature set point—and we can control them all simultaneously,” explains Georg Wolfe, chief technical officer at Agr. “We’re able to lock in the material distribution that the process engineer really wants and keep it that way [across the] environmental variations that occur around the blow molder.”
About 250 systems from the Process Pilot family are in the field. Wolfe says the systems offer reasonable payback because of additional lightweighting savings and energy reductions—as well as increased uptimes on productions lines, especially downstream where a lightweighted bottle that doesn’t blow correctly could jam the labeler or filler.
The Process Pilot automated blow-molder management system includes the Pilot Profiler, which offers real-time measurement feedback during PET container production about every container produced (photo courtesy of Agr International, Inc.).
The company says it’s now in the process of commercializing a complementary technology called CrystalView™. It automatically optimizes the re-heat stretch blow-molding process, based on information from extensive studies on the relationship between blow-molding temperature and crystallinity conducted by Wolfe and his team. For cold-mold processes, CrystalView automatically controls polymer orientation at the blow molder by detecting the very edge of where the process gets too cold and pearlescence begins to form in the feet of the bottle. For hot-mold processes, CrystalView allows molding at a temperature just below the point where haze is created.
Using CrystalView in a closed loop simultaneously with Process Pilot provides automatic, continuous management of both material distribution and crystallinity. The system uses cameras, special lighting, and sophisticated algorithms to detect pearlescence or haze before it would be visible to an operator, allowing blow molding at the optimal temperature before pearlescence or haze occurs. Wolfe adds that this combination brings immediate payback, especially for carbonated soft drink bottles, because manufacturers can drop the oven temperature a few degrees.
“With CrystalView, not only do you get the best material properties out of the bottle and the best orientation/crystallinity out of the design, but you also get the best quality performance out of the bottle,” says Wolfe. “Everything gets maximized when the bottle is stretched optimally—burst pressure, volume expansion, time to stress crack, top load, shelf-life characteristics, and dimensional stability.”
Agr says it will soon begin field testing CrystalView and expects that it will be commercially available by the fourth quarter of 2015. Customers who have Process Pilot will be able to add CrystalView to their system.
The Clear Choice over Metal and Glass
Better materials and designs are allowing lightweight plastics to find their way into more durable packaging
Previous Article Next Article
By Nancy D. Lamontagne
The Klear Can, made from clarified polypropylene, is targeted for direct competition with traditional metal cans (photo courtesy of Milliken).
Lightweighting and sustainability have long been trends in packaging, but now, as companies develop new innovations, they must think of the product’s entire life cycle. Clear plastic is working its way into food applications that traditionally have used glass or metal, where it can offer both environmental and aesthetic benefits. Novel clarifiers, processing techniques, and closure technologies mean that plastic containers look much like glass on store shelves. In addition, the demand for lighter packaging is driving the development of new technologies and analysis techniques that can ensure that performance isn’t compromised, even when less material is used.
A Holistic View
Amcor Rigid Plastics supplies consumer-driven rigid plastic packaging for the food, beverage, pharmaceutical, and personal/homecare industries. Michael Hodges, director of communications at the company, says that sustainable packaging continues to be a focus for both the company and the packaging industry.
Rather than looking at only one aspect of sustainability, Amcor takes a holistic view of how each of its products affects the environment. “Sustainability is a factor in everything we do, from the time we start designing a product until our customers put it on the store shelf,” he says. “We want to ensure each package we produce uses resources in the most effective and efficient manner possible—that’s how we define responsible packaging.”
The trend toward lightweighting is strongly linked with making packaging sustainable, but Hodges points out that there is a point where a container becomes so thin that barrier materials must be added. Thus the company likes to use the term “rightweighting” when designing packaging.
An increase in preservative-free foods and beverages as well as pharmaceuticals is increasing the demand for packaging with greater barrier protection. However, this doesn’t simply mean adding a barrier to existing packaging. “When adding in the barrier, we have to look at it from a sustainability standpoint,” Hodges explains. “We have to figure out the right barrier, so that the packaging doesn’t become a problem in the recycling stream later.”
Amcor has a sustainability group that helps with life-cycle analyses for any new bottles being designed and works in concert with FEA engineers and product engineers to perform shelf-life studies to ensure product resilience. “We want to be sure that we always protect the brand, and that we always protect the product that is going into those bottles,” Hodges says.
Enlightening Concepts
Amcor recently introduced what it says is the industry’s lightest heat-set PET container, which received a beverage award in the WorldStar 2015 Packaging Awards Competition. The 500-mL sports drink bottle combines Amcor’s Ergo technology (to improve the feel of the bottle and absorb some of the vacuum) with the company’s vacuum-absorbing base technology.
New wide-mouth jars from Amcor accept a metal lug closure and are a glass-replacement option for pasta sauces and other foods (photo courtesy of Amcor).
Weighing just 22 grams, the new bottle is approximately 30% lighter than a standard 500-mL heat-set PET container, which typically weighs about 34 grams. The reduction in material reduces life cycle energy and emissions. According to Amcor, the new bottle cuts greenhouse gas emissions by 26%, energy use by 23%, water consumption by 24%, and the amount of waste that could potentially end up in a landfill by 26%. The new product was launched in Central America with future plans for distribution throughout Latin America.
Another new product from Amcor is a heat-set wide-mouth PET jar designed to replace glass jars that hold salsas, jams and jellies, and pasta sauces. The new jars are unique in that they use the
A-PEX63™ system technology to accept a metal lug closure. The A-PEX63 system ensures sealing integrity, meets the industry average for ease of opening, and features a functional “pop” tamper-evident indicator button. The containers are hot-fillable up to 96°C and available with Amcor’s Powerflex™ vacuum-absorbing base, the company adds.
Compared to a 330-gram glass container, the 51-gram PET container reduces material mass per jar by 85%. This lowers transportation costs and allows shipments of 30% more product, by weight, per truck.
Amcor is continuing to develop new ways to meet customer demand for authentic packaging, such as technology that would allow a cork to be inserted into a plastic wine bottle, and swing top closures that can be used with plastic bottles.
Glass Replacement
Europe-based APPE, which designs and manufactures rigid PET packaging for a variety of markets, is also finding new ways to replace glass with plastic. APPE’s Kinza Sutton explains that shatterproof packaging not only appeals to food manufacturers, retailers, and consumers, but because PET is up to 85% lighter than glass, it can reduce costs in the logistical chain and lessen the carbon footprint significantly.
“It is estimated that a PET plastic jar has half of the carbon footprint of an equivalent glass jar by the time it reaches the entrance of the filling line,” Sutton says. “This is key to retailers and brands actively seeking to reduce their carbon footprint.”
For manufacturers, using shatterproof containers increases safety in the filling lines and during transport and also avoids costly product recalls. Plastic jars and bottles take up less room than a glass equivalent because their walls are much thinner and require less secondary packaging, meaning more can fit on a pallet, truck, or shelf—which further reduces costs and environmental impact.
However, there are some things to keep in mind when replacing glass with plastics. For example, some foods are sensitive to oxygen, and depending on the shelf-life requirements, may require a barrier to protect against oxygen ingress. Also, if containers are hot-filled and/or pasteurized, a special packaging plastic and/or design is needed to cope with the temperature demands. “The challenge is to make a container that will withstand filling with hot contents and/or pasteurization, and not deform when cooling,” says Sutton.
APPE recently added a set of five new round jars to its ThermaLite line. The new 100% PET jars are designed to replace glass packaging and can be hot- or cold-filled at temperatures up to 95°C and then pasteurized using most methods. The jar’s clarity provides a clear view of the contents, and their metal twist-off cap is easy to open and reclose, the company says.
APPE recently added a set of five round PET jar designs to its ThermaLite line, as lighter-weight alternatives to glass jars (photo courtesy of APPE).
APPE’s ThermaLite jars are made using a “specialist” PET resin (the company says it’s based on an APPE-designed, patent-pending formulation) and a modified manufacturing process makes the PET stronger and more heat resistant.
The jar’s series of ribs provide structural strength, enable it to maintain shape during hot filling, and help to resist container deformation when the contents are cooled and the vacuum is formed. The ribs spaced along the walls of the jar can be easily covered with a label without detracting from the aesthetics of the finished container. The jar’s base is designed to retract into the jar to absorb some of the vacuum.
APPE says it has several customers for the ThermaLite jars, which are currently used to package pickled vegetables, relishes, and pasta sauces. Shelf-life trials are in process across Europe for a wide variety of applications, and the company anticipates that the demand will greatly increase over the next few years. “APPE continues to actively promote both glass replacement and the ThermaLite jar,” Sutton says, adding that the company’s “R&D center is looking at issues such as inclusion of recycled PET and development of other shapes and sizes.”
Adding Clarity
Cristina Acevedo, global product line manager for the plastics additives business of Milliken & Company, is seeing more demand for clear parts used for food packaging, as well as improved clarity in those parts. “For example, yogurt container manufacturers previously made containers that were opaque, but now want to showcase their product in clear containers,” she says.
Milliken’s Millad NX 8000 additive improves the clarity of polypropylene (PP), allowing containers made from this material to better showcase the freshness and quality of the food. NX 8000-clarified PP can be hot-filled and microwaved and is fully recyclable. According to the company, PP also brings the advantages of consuming less energy during production than other plastic materials and producing lower carbon dioxide emissions than other commonly used transparent plastics in food and beverage packaging, such as PET and polystyrene.
Since PP is one of the lowest-density plastics, it provides an 18% weight reduction in trays compared to PET, and a higher number of parts can be generated with the same weight of material. For example, Acevedo says that thermoformers can produce 263 flat beverage lids with 1 kg of PP, but could only make 216 lids with 1 kg of PET. PP also has a lower cost per volume compared to PET and polystyrene.
The Klear Can from Milacron is made of PP clarified with Milliken’s Millad NX 8000 additives. Consumers can clearly see the foods in the container, which features a metal lid. (Photo courtesy of Milliken.)
Milacron LLC recently introduced the Klear Can, which is made from two layers of PP resin clarified with Millad NX 8000 additives. This transparent alternative to traditional metal food cans reportedly is compatible with the existing downstream canning infrastructure and has the same lids found on metal cans. Moreover, consumers can easily view the quality and freshness of fruit, vegetables, and other foods through the clear container.
The Klear Can includes a proprietary false foot with a panel inside that flexes to accommodate stress so that the can maintains its round shape. The stackable cans resist dents and other handling damage common with metal cans, thanks to PP’s flexibility. They can be recycled with already-established systems and are 40-50% lighter than metal cans of the same size, helping reduce transportation costs, fuel usage, and carbon emissions.
An ethylene-vinyl alcohol copolymer (EVOH) barrier between the two PP layers allows for a two-year product shelf life, the manufacturers report. It’s also possible to tint the material or enhance the Klear Can with in-mold labeling.
Milliken makes other additives that improve polyolefin aesthetics, physical properties, processing efficiency, and sustainability. The company’s Hyperform HPN-20E nucleating agent allows downgauging or extending shelf life
in polyethylene blown films in cereal bags while enhancing aesthetics, the company says. And the Hyperform HPN-600ei nucleating agent is used in thermoformed food packaging to improve warpage control, cycle times, and an application’s stiffness-impact balance.
Using Science to Prevent Failure
Preventing flexible packaging failure is becoming more important, with today’s trends toward lighter, thinner, less-expensive packaging. In the food industry, any puncture or tear could lead to spoilage, and for medical applications, a break in the packaging could compromise sterility and require the product to be discarded.
Henk Blom, director of technical services at Rollprint Packaging Products, Inc. is working to uncover information that would lead to a more scientific way of designing flexible packaging, using just the right amount of material for the application. Today, many companies use trial and error to design flexible packaging materials that will withstand product distribution, often having to go back and make packaging thicker if holes or tears appear during shipping tests of the final product. Such approaches to durability testing and product design are costly and time consuming.
Taber Industries’ Linear Abraser allows users to apply a specified weight on a pin that scratches back and forth on film test samples. Researchers have used this instrument to gain information about the abrasion properties of flexible packaging materials. (Photo courtesy of Rollprint Packaging Products, Inc.)
“It would benefit the entire industry if we could design a package that isn’t over-engineered or under-engineered to the point that it fails, and do that intelligently with scientific principles,” Blom explains.
Blom began his work by studying the abrasion properties of monolayer materials with different thicknesses using a Taber Industries Linear Abraser. This instrument allows the user to apply a specific weight on a pin that scratches back and forth on the material. Blom looked at the effects of applied weight and film thickness on how many cycles it took for the pin to rub through the plastic. By analyzing this data, he was able to develop an equation that provides an abrasion coefficient:
He has since begun testing multilayer structures to determine whether the performance of a two-layer structure is the same as that of the two individual materials. Audiences have been interested in his work, which he has presented at several conferences, and he has received materials from several companies for testing. “It is recognized in the industry that we don’t know how to predict packaging material failure as well as we should,” he says.
Next, he would like to collect basic mechanical and molecular-level properties for the materials he has tested to see if he can derive a second equation that relates those fundamental properties to the material’s abrasion coefficients. This second equation could allow companies such as resin manufactures to understand how to tweak material properties to achieve better abrasion resistance.
“There are a whole series of equations that could be derived or empirically created to describe not only abrasion resistance, but also puncture and flex-crack resistance,” Blom says. “Ultimately, I would like to be able to work with a customer who has a specific set of requirements and be able to design the ideal material structure for the application, with neither too much nor too little material.”
Automatic Process Control
Agr International, Inc. offers products and services designed to meet the quality assurance needs of the beverage and packaging industries. Agr’s newest offerings reportedly can help manufacturers meet the increasing demand for lightweight PET bottles without
sacrificing quality.
With today’s lightweight bottles, it’s even more important that material is distributed correctly during molding. Six years ago, Agr introduced the Process Pilot®blow-molder management system in conjunction with the Pilot Profiler® material distribution measurement system.
The Process Pilot system precisely controls and maintains material distribution to a specified thickness to within ~0.01 mm. The system uses infrared light to precisely measure the thickness of material in multiple locations, from just below the support ring to right above the gate area. Continuous average measurements from 150 bottles are used to determine which blow-molder controls will be automatically adjusted to maintain the specified material distribution.
“It’s like the cruise control on the car; however, instead of just controlling one thing like the gas pedal, we are controlling the total oven power, the individual lamp value in the ovens, the pre-blow pressure, the pre-blow start, and the preform temperature set point—and we can control them all simultaneously,” explains Georg Wolfe, chief technical officer at Agr. “We’re able to lock in the material distribution that the process engineer really wants and keep it that way [across the] environmental variations that occur around the blow molder.”
About 250 systems from the Process Pilot family are in the field. Wolfe says the systems offer reasonable payback because of additional lightweighting savings and energy reductions—as well as increased uptimes on productions lines, especially downstream where a lightweighted bottle that doesn’t blow correctly could jam the labeler or filler.
The Process Pilot automated blow-molder management system includes the Pilot Profiler, which offers real-time measurement feedback during PET container production about every container produced (photo courtesy of Agr International, Inc.).
The company says it’s now in the process of commercializing a complementary technology called CrystalView™. It automatically optimizes the re-heat stretch blow-molding process, based on information from extensive studies on the relationship between blow-molding temperature and crystallinity conducted by Wolfe and his team. For cold-mold processes, CrystalView automatically controls polymer orientation at the blow molder by detecting the very edge of where the process gets too cold and pearlescence begins to form in the feet of the bottle. For hot-mold processes, CrystalView allows molding at a temperature just below the point where haze is created.
Using CrystalView in a closed loop simultaneously with Process Pilot provides automatic, continuous management of both material distribution and crystallinity. The system uses cameras, special lighting, and sophisticated algorithms to detect pearlescence or haze before it would be visible to an operator, allowing blow molding at the optimal temperature before pearlescence or haze occurs. Wolfe adds that this combination brings immediate payback, especially for carbonated soft drink bottles, because manufacturers can drop the oven temperature a few degrees.
“With CrystalView, not only do you get the best material properties out of the bottle and the best orientation/crystallinity out of the design, but you also get the best quality performance out of the bottle,” says Wolfe. “Everything gets maximized when the bottle is stretched optimally—burst pressure, volume expansion, time to stress crack, top load, shelf-life characteristics, and dimensional stability.”
Agr says it will soon begin field testing CrystalView and expects that it will be commercially available by the fourth quarter of 2015. Customers who have Process Pilot will be able to add CrystalView to their system.