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European consortium to develop sustainable packaging that reduces food waste

A group of European companies and researchers from five different countries have joined together to develop a new material to tackle food waste. 

Called ISA-Pack, the €3.9 million ($5 million) project is funded by the European Commission (EC) Seventh Framework Program (FP7). European companies and research organizations will collaborate during a three-year period to develop fully sustainable packaging for fresh foods to extend shelf life, improve quality, and reduce waste.

UK-based Biopac, a sustainable packaging design and development company, is participating in ISA-Pack. John Bright, managing director at Biopac, told PlasticsToday through extension of shelf life, the ISA-Pack project seeks to reduce retailer supply chain wastage of fresh food produce, which includes meat, fish, fruit and vegetables, by about 75%.

"Time is running out to implement improvements for EU Directives for food waste prevention," he said. "The objective of the ISA-Pack project is to develop a flexible sustainable, active and intelligent technology platform for the packaging of fresh food produce."

ISA-Pack project will develop two biopolymer materials: bioplastic stretch wrap films suitable for the replacement of conventional PVC stretch film; and gas barrier sheets and films suitable for the manufacture of modified atmosphere packaging (MAP), including vacuum packaging.

Specifically, the group will incorporate bioplastic, moldable plastic material made up of chemical compounds that are derived from or synthesized by microbes (such as bacteria) or plants.

"Unlike traditional plastics, which are derived from petroleum, bioplastics are obtained from renewable resources, and they are biodegradable," he said. "Packaging produced from microbes that feed on sustainable natural materials may have the answer to high performance protection stretch film packaging."

The group will use unsaturated polyhydroxybutyrate copolymer materials derived from microbial fermentation of sustainable feed-stocks (including food waste itself) and incorporating low volume cross linkages, demonstrating properties suitable for gas barrier and stretch film packaging applications.

The HBcopolymer MAP materials resulting from the ISA-Pack project are anticipated to be directly suitable for the packaging of most food produce where conventional MAP packaging is used, Bright said.

Other key objectives of the project is to develop intelligent indicator systems that can be directly printed onto packaging materials, which will combine time and temperature indicators to monitor bacterial growth with freshness indicators. The project will also undertake a full lifecycle and economic assessment of all the ISA-Pack products.

Part of Biopac's responsibilities includes the investigation of the technological and economic potential for use and exploitation of the packaging applications, the market potential and value, along with identifying obstacles and barriers to commercialization such as competing technologies or solutions, and more.

The project invites food processors, retailers and consumers to participate in shaping this breakthrough program, Biopac stated.

"For retailers, ISA-Pack has the potential to extend shelf life and reduce wastage of fresh foods," said Mark Birgden, director at Biopac. "The opportunity to combine the use of sustainable materials and create significant supply chain benefits in extending shelf life is a major leap forward in fresh food packaging."

Specialty bio-based nylon makes mark in China

Chinese compounder Kingfa Sci. & Tech. Co. (Guangzhou) has been supplying polyamide 10T for several years now. Its Vicnyl semi-aromatic resin features better resistance to hydrolysis compared with PA 9T and PA 46 and employs a naturally-derived monomer.

PA 10T is based on decanediamine, a renewable raw material derived from castor beans, and terephthalic acid. The bio-based carbon content in Vicnyl ranges between 40%-60% by weight. The polymer is produced at a 2000-tonnes/yr plant.



Vicnyl PA10T has the lowest water absorption among commercialized semi-aromatic polyamides according to supplier Kingfa.
 “Thermal properties are superior to both PA 46 and PA 9T says Patrick Xu,” sales supervisor for South China. Better tensile strength and flexural modulus retention in hot water is also evident from tests, while dimensional changes are also smaller. Other advantages are said to be low warpage, high melt flow, and smooth surface finish.

According to the supplier, Vicnyl materials are suited for a wide range of applications in the electrical and electronics, automotive, and metal-replacement fields. Two grades are currently available: Vicnyl650 glass-fiber reinforced PA 10T (50% glass fiber content) with heat-deflection temperature under load (HDTUL; ISO 75-2) of 280°C, water absorption (ISO 62) of 0.15% (23°C/24 hours immersion in water), and a Ul 94 HB rating at 0.4-3 mm thickness; and Vicnyl630 with HDTUL of 240°C, water absorption of 0.6% and UL 94 rating of HB. —[email protected]

Halogen-free movement extends to colorants


Speaking to PlasticsToday at the recent Chinaplas show, Hugo Wu, regional head of sales at Clariant Chemicals (China) Ltd. (Shanghai), stated that the supplier’s LHC series of colorants for plastics guaranteed halogen levels of less than 500 ppm. Colorants are normally contaminated to a certain degree by halogens from sources such as process water but Clariant’s clean process enables contamination to be minimized. “Our interim target is to reduce halogen levels to 400 ppm, and we are targeting 100 ppm in the future,” says Wu.

Interestingly, the largest order received for LHC series of colorants was not from the electronics sector but a U.S. manufacturer of children’s footwear. “We believe there are opportunities for these colorants everywhere, and not just in consumer electronics,” says Wu. —[email protected]

PLAST 2012: Macro Engineering shows off low-shrink extrusion technology

While the focus of Canadian film and sheet extrusion systems supplier Macro’s PLAST 2012 presentation was on the food packaging market and the various models of biaxially oriented film lines which it supplies, the company had an extra trick up its sleeve this time, as well: it chose to launch its newest extrusion line for photovoltaic (PV) sheet production at the show in Milan.

For Macro, the choice of the Milan show was a logical one: the company opened a European facility relatively nearby in Mezzomerico four months ago with the goal to better serve its European customers through sales support, technical service, and future manufacturing.



Says Michele Ingegnoli, the newly appointed general manager at Macro Engineering & Technology SRL:  “We’re busy expanding  and already expect to start manufacturing after the summer.” His immediate role is to accelerate Macro Europe’s agenda of providing faster technical support, improved after-sales service, and a stronger local sales force in Europe, the Middle East and Africa.

Italy was selected as the site for Macro’s European branch because of its central proximity to the company’s European customer base and the area’s well-established network of suppliers and human resources.  “Macro traditionally purchases many Italian components,” says Ingegnoli. “So choosing Italy over, say, Germany, was a purchase-driven decision. Also, this is an area with a lot of industry and very many expert people.”

While food and medical packaging have been Macro’s biggest markets up until now, the company is also looking to expand its activities in industrial applications, such as the solar industry. Macro’s new PV sheet line, which produces the encapsulant material used in the assembly of solar modules, features Macro’s patented (pending) low-shrink extrusion technology that minimizes shrinkage in the final sheet to below 2%, which Macro claims is the lowest on the market. The reduced-shrink properties lead to significantly greater yields as less material goes to waste during solar module manufacture.

The line produces encapsulation sheet made of a variety of materials including EVA, PE, PVB, and TPU; however, the technology can also be applied to other applications where low shrinkage is required, such as rigid sheet and lamination films, or sheet where shrinkage creates issues with quality.

Macro claims the line is optimized for simplicity by creating sheet without the use of a carrier web and incorporates a two-sided embossing option that allows the sheet to be wound without need of an interleave web. The line is completed by fully automatic winding technology with zero-waste, straight-edge cutovers that create jumbo rolls up to 1m in diameter.

Do you know enough about silicone elastomers?

Sponsored by the University of Wisconsin Milwaukee School of Continuing Education, the course is scheduled for Tuesday, July 17 through Friday, July 20, 2012. It will be held at the Hilton Suites Anaheim/Orange in Orange County, CA. Included in this course will be a one-day hands-on processing class at M.R. Mold & Engineering’s Technical Center in Brea, CA, hosted by President Rick Finnie. The instruction will cover moldmaking, mold flow simulation, equipment, and manufacturing processes from a team of industry experts.

The Chair Instructor is Mel Toub, who has worked in the silicone elastomers division of Momentive Performance Materials (formerly GE Silicones) for more than 30 years. He has presented numerous technical papers to ACS, SAE, the International Silicones Symposium, and industry journals and holds several patents in the area of silicone rubber technology.

According to a newly released study from the Freedonia Group, U.S. demand for silicones is forecast to climb 5.6% annually to $4.1 billion in 2016, with silicone elastomers accounting for more than 40% of that total. The motor vehicle segment is projected to provide the best growth opportunities, driven by substantial increases in vehicle output. The medical market has been the fastest growing segment of the silicone industry in recent years, and will continue to expand strongly, said The Freedonia Group.

For more information or to register, call 414-227-3200 or visit sce-rubber.uwm.edu.

California hospital group sets the pace for sustainability programs

In 2005, California-based Catholic Healthcare West (CHW) became one of the first, if not the first, hospital group in the United States to stop using polyvinyl chloride (PVC) for intravenous (IV) bags, solutions, and tubing.

Today known as Dignity Health, the healthcare organization is a founding sponsor of the Healthier Hospitals Initiative and is leading in other sustainability efforts, including several involving plastics.

Last month. Dignity Health announced it will be the first health care system in the nation to begin using

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Sr. Mary Ellen Leciejewski, shown in the sterile processing department of Dignity Health, is directing a 16-year-old sustainability program.
pigment-free patient plastics in all of its hospitals and other care centers to reduce impact on the environment.

"We began our sustainability program formally in 1996," says Sr. Mary Ellen Leciejewski, Dignity Health ecology program coordinator.

One of the initial drivers was a push from the employees. "A lot of them were doing recycling at home, and they wanted to bring these activities into the workplace," she told Plastics Today in an interview. Another push came from a shareholder activism team. "We were asking companies to clean up their environmental act, and at the same time our house wasn't in order."

The third factor involved the sisters who brought hospitals together to form Catholic Healthcare West in 1986. "We all had phrases in our official documents that emphasized care for creation. All of this grabbed the attention of CHW, and it became a formal initiative."

One of the first major moves was a decision to no longer use PVC for IV bags and tubing--a decision that predated by seven years a similar move announced this year by healthcare giants Kaiser Permanente (Oakland, CA) and Partners Healthcare (Boston).

"That wasn't a difficult decision at all," says Leciejewski. "It was a no brainer when we looked at it. We had our eyes opened up by Health Care Without Harm." Twenty-eight organizations founded Health Care Without Harm in 1996 after the U.S. Environmental Protection Agency identified medical waste incineration as the leading source of dioxin. Most hospital incinerators have since closed.

The organization has this statement about di-2-ethylhexyl phthalate (DEHP) plasticizer used in PVC tubing on its Web site:

"DEHP can leach out from products like IV tubing, directly into the body of the patient. Medical associations and government agencies in several countries now acknowledge that there are risks, especially to the most vulnerable patients, and advocate replacing PVC and DEHP-containing products with alternatives."

Dignity Health moved to polyolefin-based replacements supplied by B. Braun Medical (Bethlehem, PA), whose Web sites states that it "is the only manufacturer of a full line of basic IV solutions in PVC-free and DEHP-free containers."

The replacements cost somewhat more, but the transition has been generally smooth.

"The only thing is that because there is no DEHP plasticizer, the products may not be quite as flexible, so you may have to handle them a little more gently," says Leciejewski. "It was not a big change or a big deal. What was a big deal is that I knew in my heart that we were doing the right thing." She said there were no alternative products for some applications.

There was no discernible change in patient health as a result of the change. "It could be one of those things like smoking where you really don't know until 30 or 40 years down the line what the impact is. I wish we had that magic button where we could see that. But again, it's first 'do no harm'. If we know that DEHP is not going into patients, it can only be a good thing."

There are no other specific types of plastics that Dignity Health is targeting for elimination or phase-out.

"There are so many plastics in hospitals. We're trying to reduce our use of it. We're going to reusables where we can. That's a step up the ladder." One example is a reusable sharps container called Bio Systems from Stericycle. With sterilization, they are being used 600 times at Dignity Health before they need to be taken out of service. Pharmaceutical containers are also being reused.

Each hospital in the system has an "eco contact" who keeps an eye out for possible problems. As a result, there is growing emphasis on reusable mugs made from stainless steel in place of polycarbonate bottles that contain bisphenol A (BPA).

Dignity Health operates 40 acute care hospitals and 150 clinics and ancillary care centers. Net operating revenues last year were $10.6 billion. Of the 55,000 employees, 10,000 are physicians.

The system  made news last month when it announced plans to use plastics that are dye-free.

The hospital is already planning the next step. Dye-free plastic pitchers used for water in patient's rooms are being replaced with reusable stainless steel pitchers in a pilot program.

In 2011, Dignity Health diverted 198,000 pounds of medical equipment from landfills and saved $5.6 million by increasing use of reusable products.

In 2011, through the use of reusable sharps containers, Dignity Health eliminated 1,344,227 tons of red plastic and 73,098 tons of corrugated packaging containers waste, and prevented carbon dioxide emissions equivalent to 31,255 gallons of gasoline.

Not all environmental pitches are well received at Dignity Health. "We want to make sure that no green washing is going on. We want to make sure that it is really necessary and it really does work."

Dignity Health is also actively implementing a comprehensive chemical review program called the Green Chemical Initiative adopted in 2009. The goal is to get suppliers to make the types of chemicals used in their products more transparent so they can be analyzed and replaced if necessary. Antimicrobial agents are being studied now to make sure that endocrine disrupters are not used in the hospitals.

"We can have all of this healing going on in the hospital, but what good is it if we're not healing the planet at the same time. We're going together in the future or we're not going."

Starbucks, ConAgra Foods talk packaging sustainability initiatives, challenges at TAPPI 2012

Seattle, WA - As TAPPI attendees sipped on white coffee cups with a green siren logo, Brent Denniston, Starbucks VP of global procurement, said the company is fully aware of the profound effect of its packaging.

"Our packaging is an asset, but it's also a liability," Denniston told TAPPI members and attendees. "What is iconic to our company is our cup, people associate their experiences with the brand through it. But they also associate it with not being environmentally responsible."

"Packaging waste is the number one environmental issue to many consumers," he said.

At the TAPPI PLACE (May 6-9; Grand Hyatt Seattle) Conference, Denniston and Gail Tavill, vp of sustainable development for ConAgra Foods, both spoke about packaging for their brands. The topic of packaging sustainability and recycling were prevalent in both speeches.

Despite a somewhat unmatchable brand loyalty in the coffee space, Starbucks still takes heat due to the potential negative environmental impact of its disposable cups. Starbucks paper coffee cups, partially made from recycled content, are constructed with a polymer-based liner to prevent hot liquid from leaking.

Dennison highlighted several initiatives the company has undertook to produce a greener cup such as rolling out plastic cups for its cold beverages that are produced with polypropylene cups and lids, and launching new lightweight plastic cups to reduce resin consumption.

While Starbucks is interested in composting, he said the company's first preference is recycling.

However, Denniston said one major challenge of recycling is recovering.

As of now, once the cups leave the stores, it's up to the consumer to recycle the product, but recycling success depends on the availability of commercial recycling services where the company's stores are located, he said.

In an attempt to provide a solution to the recycling issue, Starbucks has launched in-store recycling programs at select stores. While the program has hit some hiccups along the way, Denniston said the company is committed to eventually offering in-store recycling on a wide scale.

In addition, Starbucks has a goal of making 100% of its cups reusable or recyclable by 2015.

"It's a challenge, creating a dynamic where the consumer will bring in a reusable cup, that we have to figure out how to leverage," Denniston said.

He hinted there maybe a product to address this initiative hitting stores in the next coming months.  

Beyond cups

Starbucks is also looking into reducing packaging from its whole bean and ground coffee products, and various other packaging products.  

"We have a focus on leveraging packaging technology to improve freshness and product shelf life," he said. "I'm sure there is technology out there we haven't explored to help reduce waste and have a longer shelf life."

With regards to its packaged coffee product, Denniston said Starbucks isn't satisfied with the packaging.

"When you see our packaged coffee product, it doesn't set itself apart from the competition, in terms of shopability," he said. "We have a big focus on innovation in flexible packaging."

ConAgra Foods' green efforts

Gail Tavill with ConAgra Foods said sustainability isn't just about what's right for the environment, there's also a business case for it.

"Companies that follow more sustainable practices have more sustainable economics," she said.

Since packaging arguably has a reputation as wasteful, Tavill said it's important to remind people about the value of packaging.

"If a package breaks, causes food to spoil - then we fail," she said. "Packaging needs to be part of the solution, not the problem. Our goal is to embrace the value of packaging and strive to make it as efficient as possible."

She pointed out various packaging examples the company implemented for a more efficient and sustainable use of materials.

ConAgra Foods was the first company in North America to incorporate post-industrial recycled polylactic acid into shrink film packaging materials. By collaborating with its suppliers, the company converted 260,000 pounds of resin from non-renewable resources (PVC and PET g) to PLA. The company's PLA shrink film contains more than 50% post-industrial recycled material, and it uses this material for tamper-evident seals on some of ConAgra Foods' table spreads.

"We know there are challenges with PLA and how it can impact the bottle-to-bottle recycling strategy," she said. "But we have strict restrictions on PLA and we make sure it doesn't stay with the package because we don't want potential contamination."

The company also uses recycled PET in some of its frozen food trays. ConAgra uses several sizes of the trays for Healthy Choice, Banquet, Kid Cuisine, and Marie Callender's brands. Nearly all are pigmented black.

Still, rPET and virgin PET have somewhat different functional properties and chemistry, which created several challenges in blending, extruding, and thermoforming the trays so they would meet both the company's and FDA standards.

However, once those hurdles were tested and cleared, the trays were ready for the public.

"We do use rejected rPET for some of the microwave dishes," she said. "Because the dishes are eventually colored we don't care about the clarity."

Tavill said sustainability is complicated process from all perspectives.

"You can't have radar vision, one decision has consequence to others," she said. "We have to make sure what we put out can be recovered for recycling."

NOVA exits styrenics market

Insulating building products supplier PFB Corp. is vertically integrating its expandable polystyrene (EPS) supply via the acquisition of NOVA Chemicals Corp.'s Performance Styrenics business, which includes EPS and Arcel resin products.

NOVA Chemicals will acquire an equity stake in PFB and hold two seats on its board, as part of the deal, with Robert Snyder, VP Performance Styrenics for NOVA also to join PFB as COO.

SIPS panel
Structural Insulating Panels Systems sandwich EPS between wood panels.

In a release, PFB stated, "With the world now focusing on sustainable building products, it is the time for our industry to provide vertically-integrated EPS product solutions that provide environmentally friendly alternatives to the construction industry."

The deal's definitive agreements are to be executed during the second quarter, with closing to occur during the second half of 2012, pending the approval of regulators, shareholders, and the boards of NOVA and PFB.

PFB has two subsidiaries: Plasti-Fab Ltd., which operates in Canada, and PFB America, which operates in the U.S. NOVA Chemicals was acquired by Abu Dhabi's International Petroleum Investment Company (IPIC) in February 2009.

NOVA's remaining resin business consists of its polyethylene (PE) brands: Surpass, Sclair, Novapol, suitable for film extrusion, injection molding, rotational molding, and blowmolding. In 1998, NOVA acquired Huntsman's North American and European styrenics businesses.

In addition to insulating concrete forming systems used to build insulated foundations and walls from concrete, PFB supplies Insulspan Structural Insulating Panels Systems (SIPS).

Sleeve labels picking up steam


There are three defined formats: Transverse Directional (TD) oriented film used for heat-shrink sleeves, stretch sleeves, and machine directional (MD) heat-shrink sleeves. All of these formats are based on polymer film substrates, and all provide 360-degree, high-quality graphics and can applied to bottles and containers with various shapes and curves. This capability of “head-to-toe” coverage is one of the major benefits driving brand owners to sleeve labels.
 
Some of the trends that Llewellyn noted in his presentation include more global brand owners specifying materials other than PVC. Yet, PVC represents 53% of the materials used in sleeve labels. PETG accounts for 21% of the materials used and he added that PETG is a substrate for PVC material in many markets.
 
Asia represents the largest market for global label demand at 34%; Europe is second at 29%, and North America is third at 22%. South America represents 10% of global label demand and Africa represents 5%. For sleeve labels, Asia has a 47% share of the market; Europe has a 30% share; North America has a 19% share; and Africa has a 3% share, with South America lagging at 2%.

“Growth is strongest in South America, China, and India for heat-shrink sleeve systems,” said Llewellyn. “In other markets there are recycling and environmental demands and concerns.”
 
Other trends include an increased usage of steam tunnels for heat-shrink sleeve applications, and a growing availability of alternative sources of roll-fed sleeves. With respect to end markets, Llewellyn noted that most remain centered on food and beverage containers with gains in household chemicals from IML, and in household chemicals and personal care products from pressure-sensitive labels.

Some developments for the sleeve label market include improving labeling speeds, thinner films, matte films, opaque films, and co-extruded films. There are also higher levels of shrinkage rates in both MD shrink and heat-shrink sleeves. While PLA is being looked at for heat-shrink sleeving, Llewellyn notes that PLA is “not so easy to convert and separate out from the recycling stream.”

Challenges to sleeve labels include the usual price increase of polymer materials, and the low-price film exports from China. The European market has environmental concerns over PLA materials being used for labeling PET containers, and the contamination of the recycling stream.

That concern is also impacting the use of shrink sleeve labels in the U.S. A report released on March 1, 2012 by the National Association for PETS Container Resources (NAPCOR), noted that the incidence of PET boggles using full-wrap shrink labels was first noted in its 2007 bale composition study at levels around 0.65% by weight. Reclaimers at the time reported that the bottles were contributing to increased residual contamination in the recyclate produced.

NAPCOR’s 2011 bale study showed an increase to 3% by weight of all bottles collected in the U.S., and to 3.5% of all containers collected through curbside recycling. “What was formerly a nuisance has now become a crisis,” said the NAPCOR report, “as reclaimers, particularly those focused on manufacturing RPET suitable for use in packaging applications such as bottles and thermoformed products, have had to remove these full-wrap label bottles, either manually or by reprogramming autosort equipment.”

Mayra Gonzalez, market development manager for Eastman Chemical Company, noted in her presentation at the Sleeve Label Conference that as shrink sleeve labels become more popular for their “attention-getting appeal,” the industry is under increased pressure from the recycling industry, in particular NAPCOR, whose study found “all sleeve labels to be unsatisfactory, with the PP wraparound the only acceptable label." Eastman launched its Embrace shrink-film product in 1999 and in 2007, introduced Embrace LV low-shrink film.

“They’re looking for the plastics packaging industry to find a viable solution in the recycling stream,” said Gonzalez. “We’re looking to simplify the shrink-sleeve label chain, asking what happens to the package when the consumer has it in hand?” Would the consumers remove the labels?”

One answer to make the removal process easier is the perforated label, which many shrink over-wraps and sleeves have, she pointed out. “The Sustainable Packaging Coalition believes that teaching people to remove the shrink sleeve is also a solution,” Gonzalez added. “De-labeling equipment at the recycler’s might provide a way to recycle the labels. If we get labels off complete is that better than glue applied? Can shrink sleeves be recycled?”

According to the NAPCOR report, in 2012 PET recyclers reported over 6 million lb of labels recovered and sold to end users. Currently, however, some full-wrap label bottles are being sold as “out-throws” at prices significantly below market; some are being blended into low-value applications; and many are simply being stockpiled as reclaimers look for a solution or a market. “All of this has significant economic impact on the PET bottle reclamation industry,” said the report. “If the PET recycling infrastructure is to remain sustainable, this issue cannot be ignored; it needs to be addressed now.”

Gonzalez noted that Eastman’s efforts to teach consumers to remove the shrink sleeve included the innovative talents of 16 students from the Virginia Tech industrial design and graphics arts school. During a six-week project, these students were to develop East Embrace copolyester shrink-film label concepts for Dr. Enuf, an energy drink that is popular in northeast Tennessee. The project would be to develop a program that would entice consumers to remove the label and recycle the container.

Students worked in teams of three—two graphic designers and one industrial designer. The winning designs created by Kyle Waldrop and Alyssa Deilmann, both graphic designers, and Kelly Knapik focused on current and future markets. The new market design features a textured label reading, “Oh, baby, take it off!” and looks like it’s already peeling off the bottle.

“The idea of making sustainability is really critical,” said Ed Dorsa, associate professor of industrial design, School of Architecture and Design, at Virginia Tech. “One of the big points on our project was making sure that Embrace film would be pulled off and then the bottle would be recycled.”

Gonzalez added that some type of reward might be offered for the removal of shrink labels. “We offered money for aluminum cans—why can’t something like that be promoted for shrink labels?”

Fiber laser process targets medical plastics welding

Fiber laser process targets medical plastics welding

A powerful laser technology originally developed for the telecommunications industry is now targeting plastic welding, and has significant implications for medical markets because it eliminates use of dyes and other additive extractables. It may also expedite the welding of polyolefin elastomers that are bidding to replace polyvinyl chloride (PVC) for intravenous tubing and bags.

The technology, developed in Russia in the 1990s by academic researchers, was introduced at NPE2012 and discussed in a presentation at Antec by IPG Photonics (Oxford, MA), which had never exhibited at NPE before but now views nonmetallic welding as one of its biggest growth areas.

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The melt zone is visible in 20 layers of 0.1-mm-thick LDPE welded with 90 watts of laser power at 1940 nm. Source: IPG Photonics

"One of the limitations of traditional laser welding is that you had to have a clear and a colored material for the laser to work," a processor told PlasticsToday after being asked what he thought was the most interesting new sealing technology he saw at the show. "IPG Photonics has figured out a way to seal clear materials."

A different approach

The new approach is based on fiber lasers that use semiconductor diodes as the light source to pump specialty optical fibers, which are infused with rare earth ions. "Fiber lasers are not fiber-delivered lasers," Tony Hoult, general manager - West Coast operations for IPG Photonics, told PlasticsToday in an interview.

In traditional laser technology, developed more than 50 years ago, an energy source excites or pumps a lasing medium that produces laser photons of a particular wavelength; when focused this causes melting of the target material. The two primary types are named for the materials used to create the lasing action: CO2 gas lasers and crystal lasers. The most common crystal lasers use yttrium aluminum garnet—YAG crystals infused with neodymium.

IPG Photonics is targeting plastics welding for medical devices with thulium fiber laser systems that operate in the spectral range of 1800 to 2100 nm. A 1940-nm system was demonstrated at NPE2012.

"At this wave length you get more absorption in almost all clear polymers because the wavelength is closer to some vibration frequencies of the carbon-hydrogen bond (in plastics)," Hoult said in the interview. "When you bond polymers, you want something between 0 and 100% absorption and that's what you get with the thulium fiber laser."

No modifications required

One of the benefits to this welding technique is that no material modifications or additional infra-red

absorbing layers are necessary to improve the absorption of the laser beam in the polymer. The reason is that the absorption of the laser beam is taking place in the bulk of the polymer, not just at the surface or at the interface.

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Samples at NPE2012 showed 2-mm-thick polycarbonate welded at 30 mm/sec at 80 watts. Source: IPG Photonics

When conventional near infra-red lasers are used, no controlled melting of clear polymers is possible unless specific infra-red absorbers such as the Clearweld infra-red absorbing inks or the Lumogen or Lazerflair dyes are used. Clearweld inks add cost and require separate dispensing equipment. Adding dyes to the material at the master-batch stage also adds cost and limits flexibility. Another consideration is that many hospital systems are now avoiding use of chemicals that are considered extractables.

"The medical device people love this because it's a uniquely controllable thermal process," Hoult said. It provides more flexibility in types of welds that can be designed. The IPG technology also allows welding of all types of thermoplastics regardless of polarity, a limitation in some other plastics welding systems. Conventional, nonproprietary radio-frequency (RF) welding of films has been limited to polar resins with high dielectric loss factors—particularly flexible PVC and thermoplastic polyurethane.

The fiber laser is a tool that could ease substitution of PVC with thermoplastic olefins in IV bags and tubing.

California development center

Three years ago IPG Photonics opened an 8000-ft2 Laser Micro Processing Applications Facility in Santa Clara, CA that concentrates on the advancement of laser micro-processing for the photovoltaic and medical device industries.

"Fiber lasers were not initially considered for welding polymers as melting and flow of polymers occurs at much lower temperatures than metals, hence much lower power density (in the order of ~ 200 W/cm2) is required than for metal processing (~ 107 W/cm2)," said Hoult. "This low power-density requirement can be addressed by those laser types that have intrinsically low focusability such as direct diode lasers. Polymer welding uses the focusability of fiber lasers differently: significantly longer focal length lenses with a much lower sensitivity to focus position can be used."

Hoult said that the initial suitability of a clear polymer needs to be confirmed by checking its absorption under fixed conditions before a specific application can be undertaken. This is done by placing a sheet of the polymer above a laser power meter that has been calibrated for the 1.5 or 2 μm laser wavelength.

Hoult declined to provide specific prices for the thulium fiber laser system, but said it is cost competitive with other types of plastic sealing processes. The system has been used for surgical applications for more than 10 years, and is now being tested by a Who's Who of medical device OEMs for plastics sealing, Hoult told PlasticsToday.