Combat the skilled labor shortage using this comprehensive resource to train your own plastics processing experts.
Deep dive into the basics of blending versus dosing, controls, maintenance, process integration and more. Stretch Film Screwfix
This Knowledge Center provides an overview of the considerations needed to understand the purchase, operation, and maintenance of a process cooling system.
Learn about sustainable scrap reprocessing—this resource offers a deep dive into everything from granulator types and options, to service tips, videos and technical articles.
Scheduled and unscheduled production disruptions, and projected higher feedstock costs could be key factors.
Entering 2025, prices of major commodity and volume resins are generally in a ‘buyer’s market.’
While PE price reductions were not as apparent, they too were following the year-end price trajectory of PP, PS, PVC and PET.
Going into fourth quarter, prices of the five commodity resins were heading downward, barring supply interruptions.
This month’s resin pricing report includes PT’s quarterly check-in on select engineering resins, including nylon 6 and 66.
While prices moved up for three of the five commodity resins, there was potential for a flat trajectory for the rest of the third quarter.
Resin drying is a crucial, but often-misunderstood area. This collection includes details on why and what you need to dry, how to specify a dryer, and best practices.
Take a deep dive into all of the various aspects of part quoting to ensure you’ve got all the bases—as in costs—covered before preparing your customer’s quote for services.
In this collection of articles, two of the industry’s foremost authorities on screw design — Jim Frankand and Mark Spalding — offer their sage advice on screw design...what works, what doesn’t, and what to look for when things start going wrong.
In this collection, which is part one of a series representing some of John’s finest work, we present you with five articles that we think you will refer to time and again as you look to solve problems, cut cycle times and improve the quality of the parts you mold.
Gifted with extraordinary technical know how and an authoritative yet plain English writing style, in this collection of articles Fattori offers his insights on a variety of molding-related topics that are bound to make your days on the production floor go a little bit better.
In this three-part collection, veteran molder and moldmaker Jim Fattori brings to bear his 40+ years of on-the-job experience and provides molders his “from the trenches” perspective on on the why, where and how of venting injection molds. Take the trial-and-error out of the molding venting process.
Mike Sepe has authored more than 25 ANTEC papers and more than 250 articles illustrating the importance of this interdisciplanary approach. In this collection, we present some of his best work during the years he has been contributing for Plastics Technology Magazine.
In this collection of content, we provide expert advice on welding from some of the leading authorities in the field, with tips on such matters as controls, as well as insights on how to solve common problems in welding.
Mold maintenance is critical, and with this collection of content we’ve bundled some of the very best advice we’ve published on repairing, maintaining, evaluating and even hanging molds on injection molding machines.
Thousands of people visit our Supplier Guide every day to source equipment and materials. Get in front of them with a free company profile.
Whether or not your process setup includes adding cushion depends on multiple factors, including the part being molded. Learn when and how to effectively apply cushion in your process.
Molecular weight might seem like an abstract concept, but it plays a crucial role in determining the behavior of plastics during processing and in their final applications.
When Jeff Smith received a notice evicting his promising business out of his house, it could have been the end of Elite Biomedical Solutions’ and Elite Precision Plastics’ stories before they really got started, instead it was just the beginning.
Future expectations reach 2024 high on the heels of the recent election.
Researchers work to scale up a biomanufacturing process for succinic acid, an important building block for industrial chemicals and a biopolymer precursor.
Plastics auxiliary and primary processing equipment was optimized for running pellets; here’s how you can adjust to the bulk density differences of flake and regrind in drying, conveying, mixing, feeding and processing.
The Plastics Technology Expo (PTXPO) returns March 18-20 at the Donald E. Stephens Convention Center in Rosemont, Illinois, with elements old and new.
Entering 2025, prices of major commodity and volume resins are generally in a ‘buyer’s market.’
Leading maker of portable sanitation products knew thermoforming, sheet extrusion, rotomolding and injection molding. Then it found the missing link to higher productivity and new markets: blow molding.
DCT saves 60 man-hours per week by shifting from paper records and discrete spreadsheets to a shared, automatic production monitoring platform.
The Plastics Technology Expo (PTXPO) returns March 18-20 at the Donald E. Stephens Convention Center in Rosemont, Illinois, with elements old and new.
The third iteration of the event takes place March 18-20 in Rosemont, Illinois, providing three days of exhibits, technical education and professional networking.
Plastics Technology’s Hot Shots parts competition is accepting submissions for the 2025 contest, with winners to be announced at PTXPO 2025.
Topping five other entries in voting by fellow molders, the Ultradent team talks about their Hot Shots sweep.
Serendipitous Learning Opportunities at PTXPO Underscore the Value of Being Present.
Introduced by Zeiger and Spark Industries at the PTXPO, the nozzle is designed for maximum heat transfer and uniformity with a continuous taper for self cleaning.
Center will be dedicated to product engineering, materials science and manufacturing technologies.
Südpack’s Multifol Extreme film is well suited for greasy, protein-rich and frozen foods
Across all process types, sustainability was a big theme at NPE2024. But there was plenty to see in automation and artificial intelligence as well.
Exhibitors and presenters at the plastics show emphasized 3D printing as a complement and aid to more traditional production processes.
The Plastics Industry Association (PLASTICS) has released final figures for NPE2024: The Plastics Show (May 6-10; Orlando) that officially make it the largest ever NPE in several key metrics.
Discover how artifical intelligence is revolutionizing plastics processing. Hear from industry experts on the future impact of AI on your operations and envision a fully interconnected plant.
Mixed in among thought leaders from leading suppliers to injection molders and mold makers at the 2023 Molding and MoldMaking conferences will be molders and toolmakers themselves.
After successfully introducing a combined conference for moldmakers and injection molders in 2022, Plastics Technology and MoldMaking Technology are once again joining forces for a tooling/molding two-for-one.
Multiple speakers at Molding 2023 will address the ways simulation can impact material substitution decisions, process profitability and simplification of mold design.
When, how, what and why to automate — leading robotics suppliers and forward-thinking moldmakers will share their insights on automating manufacturing at collocated event.
As self-imposed and government-issued sustainability mandates approach, injection molders reimagine their operations.
August 29-30 in Minneapolis all things injection molding and moldmaking will be happening at the Hyatt Regency — check out who’s speaking on what topics today.
Get your clicking finger in shape and sign up for all that we have in store for you in 2023.
Molding 2023 to take place Aug. 29-30 in Minnesota; Extrusion 2023 slated for Oct. 10-12 in Indiana.
With the fluctuating costs of materials and the absence of technical staff, it is increasingly important to optimize your workflow and utilize equipment to the best of its ability. This webinar will cover the best blending practices by discussing the characteristics of the best blender, how to use the blender to the best of its ability and how to integrate the blender with other elements of the work cell. Agenda: Characteristics of the best blender How to use the blender to the best of its ability How to integrate the blender into other elements of the work cell
Understanding plastic material compatibility and joint design is critical to achieving optimal weld strength and meeting industry standards. Discover how to optimize joint configurations and manage material properties to enhance weld reliability, minimize defects and boost efficiency. Gain key insights to optimize your laser and ultrasonic plastic welding processes for better results. Agenda: Learn the principles of plastic material compatibility and their impact on weld strength Discover best practices for joint design to ensure optimal welding integrity Explore strategies for optimizing weld joint configurations for enhanced reliability Understand how to manage material behavior to minimize defects during welding Gain insights into achieving compliance with stringent industry standards
Join this webinar to explore the transformative benefits of retrofitting your existing injection molding machines (IMMs). Engel will guide you through upgrading your equipment to enhance monitoring, control and adaptability — all while integrating digital technologies. You'll learn about the latest trends in IMM retrofitting (including Euromap interfaces and plasticizing retrofits) and discover how to future-proof your machines for a competitive edge. With insights from industry experts, it'll walk you through the decision-making process, ensuring you make informed choices that drive your business forward. Agenda: Maximize the value of your current IMMs through strategic retrofitting Learn how to integrate digital technologies to enhance monitoring and control Explore the benefits of Euromap interfaces and plasticizing retrofits Understand how retrofitting can help meet new product demands and improve adaptability Discover how Engel can support your retrofitting needs, from free consultations to execution
The aim of this presentation is to guide you through the factors and the numbers that will help you determine if a robot is a smart investment for your application. Agenda: Why are you considering automation? What problems are you trying to solve? How and why automation can help Crunch the numbers and determine the ROI
An overview on the use of chemical foaming agents (CFAs) to successfully foam single and multilayered rotational molding parts, this webinar will illustrate the multiple benefits rotational molders can achieve, including reducing resin consumption, decreasing part weight, enhancing wall thickness and improving structural rigidity. Agenda: Charging the mold Dosing ratios Venting Optimal decomposition temperatures, cycle times and drop times for drop box applications Cooling considerations
Join Engel in exploring the future of battery molding technology. Discover advancements in thermoplastic composites for battery housings, innovative automation solutions and the latest in large-tonnage equipment designed for e-mobility — all with a focus on cost-efficient solutions. Agenda: Learn about cutting-edge thermoplastic composites for durable, sustainable and cost-efficient battery housings Explore advanced automation concepts for efficient and scalable production See the latest large-tonnage equipment and technology innovations for e-mobility solutions
ANTEC® 2025, SPE's Annual Technical Conference, showcases the latest advances in industrial, laboratory, academic, and international work focused on plastics and polymer science. ANTEC® will address a range of plastics technologies, polymer research, new materials, innovative processes, and more. There will also be a focus on scientific, technical, or industrial problems and their solutions. In addition to a comprehensive program, ANTEC® 2025 will offer exceptional networking opportunities, our prestigious SPE awards, symposiums, and our exclusive ANTEC® All-Access VIP Experience.
The International Conference on Polymers and Composites (ICPC) aims to bring together leading academic scientists, researchers and research scholars to exchange and share their experiences and research results on all aspects of polymers and composites. It also provides a premier interdisciplinary platform for researchers, practitioners and educators to present and discuss the most recent innovations, trends, and concerns as well as practical challenges encountered and solutions adopted in the fields of polymers and composites.
Each year Products Finishing partners with thousands of finishing operations in the U.S. to celebrate National Surface Finishing Day (NSFD) on the first Wednesday in March. NSFD is designed to celebrate and showcase the industry to trade schools, businesses, officials and media, as well as to celebrate employees and staff. The overarching goal of NSFD is to bring further awareness to the important roles plating and coating facilities play in their communities. Facilities are encouraged to host events and work with local media to build awareness about the contributions made by the surface finishing industry. For a helpful guide to reaching out to media outlets, download the NSFD toolkit here. How can you celebrate? Share your company’s story Hold an open house where the public can check out your facility –— either in person or virtual Offer student shop tours to local trade schools Invite local elected officials to visit and get to know your staff Celebrate your employees Share news about what you’re doing on social media and use the hashtag #NationalSurfaceFinishingDay or #NSFD
In its 25th edition, Plastimagen seeks to reaffirm as the main gateway to the plastic sector in Mexico and Latin America. This event will bring together a variety of leading leaders of the plastic industry, including capital goods, suppliers of raw materials, investors, representatives of organizations and members of the Academy. The event will have as its main objective to promote the transformation of the industry towards a more sustainable model. This will be sought to facilitate robust economic development, and providing solutions aimed at achieving a circular economy. PLASTIMAGEN® MEXICO IS THE BIGEST INTERNATIONAL EXHIBITION FOR THE PLASTICS PROCESSING INDUSTRY IN MEXICO AND LATIN AMERICA. This Event Brings Together The Entire Production Chain With Top Suppliers To Meet The Needs of Various Industries. PLASTIMAGEN® MEXICO 2025 WILL FEATURE OVER 870 COMPANIS REPRUBOVE 1,600 Brands from More than 27 Countries, 14 International Pavililons, and A Specialized Pavilion by the National Association of Plastics Industries Industries In Mexico (Anipac). You'll see the latest in plastics processing, design innovations, and materials that support the circular economy.
PTXPO 2025 is a comprehensive showcase of cutting-edge technologies and innovations within the plastics molding industry. Join fellow molders, moldmakers, brand owners, OEMs and their full suite of suppliers in Rosemont, Illinois, for three days of nonstop networking, education and business development opportunities.
Critical Cleaning Hands-on Workshop Do it; learn it! The one-day workshop teaches how cleaning and cleanliness testing work. By participating in hands-on exercises of techniques for cleaning and cleanliness verification, attendees gain the understanding and knowledge to make practical, effective, and sustainable manufacturing decisions. While exercises are supplemented by demonstrations and tutorials, the workshop is not death by PowerPoint! Topics include aqueous, solvent, and “non-chemical” cleaning, including cleaning chemicals and cleaning processes (spray, ultrasonics, cyclic nucleation, in-line, batch). Most manufactured product and product contact surfaces require cleaning during (and sometimes after) manufacture and assembly. Examples of areas where effective cleaning is essential include: metal fabrication, product assembly, optics, electronics, microelectronics, wafer fab, medical devices, aerospace/aeronautics, military, and additive manufacturing. WHAT DO YOU CALL CLEANING? There are many different terms for cleaning. Cleaning Precision Cleaning Critical Cleaning Safety/Critical Cleaning Surface Prep for Finishing Technical Cleanliness Residue Removal WHO WILL BENEFIT FROM THE WORKSHOP If you or your company fabricates, finishes, maintains or repairs product or product contact surfaces (like reaction vessels), this workshop is time well-spent. If you sell chemicals or cleaning equipment, this workshop will help you better understand and optimize the market for your products. Examples include: Manufacturing Engineers Product Designers Managers Sales and Marketing Managers Facilities Personnel Assemblers, operators Process Technicians Quality Control Personnel Regulatory Affairs Experts (industry, military, and government) Safety/environmental professionals Participants will receive a PDF Certificate of Completion with continuing education credits from Sam Houston State University.
In the hyper-competitive stretch-film market, more layers often mean more market share. Moving from five layers to seven or nine can give an edge through higher performance or reduced cost.
Downgauging and sophisticated structures make today's stretch film go farther. Pliant's newest seven layer line puts 9,000 ft of 51-gauge stretch film on a foll, vs. only 5000 ft of conventional 80-gauge film.
Making seven-layer film with high mLLDPE content at high output rates requires North America's largest-diameter cast chill roll. (Photo: Pliant)
Pinnacle Films makes only seven-layer, high-performance stretch films using mLLDPE. Last year it added a second seven-layer line.
High-performance seven-layer films can stretch farther than most wrapping machines can pull them, even on a load like this with protruding corners. (Photo: Highlight Industries)
The world's first nine-layer stretch-film line at Sigma Stretch Films doesn't use mLLDPE. Its extra layers create a commodity film less expensively.
Automatic core loading, roll unloading, and boxing is more prevalent in Europe, where labor costs are higher. (Photo: SML)
Stretch-film processors were used to a market that doubled every five years. Between 1985 and ’90, demand grew from 250 million lb/yr to 500 million lb, and from 1990 to ’95 it swelled to 1 billion lb. Even as recently as five years ago when five-layer stretch film swept the market, resin demand still grew in double digits. But for the past couple of years, stretch-film resin demand stalled at around 1.4 billion lb. Stretch film is 65% to 70% cast film, mostly for machine wrapping, and 30% to 35% blown film, mostly for commodity hand wrap and a few highly puncture-resistant specialty films.
Competition in this film sector is a cutthroat fight for market share. Processors’ profits are often in fractions of a cent per lb, and the rate of new machine installations is down to only a couple a year. The only North American processors who appear to be growing and reinvesting are those making the new highly layered films.
When five-layer stretch film was introduced in the mid ’90s, it replaced a lot of one- and three-layer films composed of hexene and/or octene LLDPE. It required a fourth extruder and a five-layer feedblock and allowed use of less-expensive butene LLDPE reinforced with thin support layers of then-new metallocene LLDPE. A typical five-layer structure could be A-B-C-B-A with 10% hexene LLDPE surface skins, 20% mLLDPE subsurface layers, and a 40% butene LLDPE core.
Stretch-film machines grew larger and output rates rose along with the number of layers. The standard five years ago was five 20-in. rolls up and three layers. Now it’s six rolls up and five layers. Five-layer stretch now accounts for 40% of all stretch film made in North America, and metallocene resin use has grown from nothing in 1995 to 12% of all LLDPE used in stretch film.
But mLLDPE is pricey, so processors went to seven and nine layers mostly to enable use of more wide-spec or butene LLDPE and less mLLDPE—and, in a few instances, to create higher-performing films. For example, all makers of seven-layer stretch film say they can replace thicker films having fewer layers without sacrificing load-retention capacity.
For the past few years, all the cast stretch-film lines installed in North America have been designed for five or more layers. They set new records for numbers of layers—first seven, then nine. Now processors and machine builders are talking about 11, 14, and even 70 layers.
“We commercialized microlayer feedblock technology for barrier properties, but stretch film could also be an application. We can produce layers at the angstrom thickness level [1 angstrom = 0.0001 micron] or tenths of a percent of film thickness,” says Gary Oliver, senior corporate scientist at Cloeren Inc. “Processors are interested, but nobody is testing it yet.”
Most of the new highly layered lines went to new players in the stretch film business, bringing shifts in market share. Chaparral Films in Mauriceville, Texas, was the first to come out with five-layer stretch film in 1994 and reportedly was the first with seven layers in ’96, though this was never publicly announced. Chaparral made even higher numbers of layers on a developmental basis, according to sources at Cloeren, which built the dies and feedblocks and was an investor in Chapparal. (ITW Stretch Packaging Systems in Glenview, Ill., bought Chaparral in 1996 but makes only five-layer films.)
Poly Rafia in Atlacomulco, Mexico, was next in line with seven-layer capability in 1996 and added a second line in 2001. When Quintec Films Corp. in Shelbyville, Tenn., and Pinnacle Films Inc. in Charlotte, N.C., started up in the fall of ’98, both new firms made nothing but seven-layer stretch film. Quintec was awarded U.S. Patent #6,265,055 in July 2001 for stretch films with “two outer layers and at least five inner layers.”
“With enough extruders and layers, you can make a cost-effective, high-performance film with metallocenes. That’s the market opportunity we saw,” says William Rice, president of Pinnacle, which installed a second seven-layer line last April. “Most old established players in this field can’t afford to add new higher-tech capacity. They aren’t reinvesting in new seven-layer lines.”
However, two longer-established processors have added seven-layer stretch-film capacity since then: Pliant Corp. of Schaumburg, Ill., and AEP Industries Inc. of S. Hackensack, N.J.
Meanwhile, Sigma Plastics Group, a major bag-film maker that has been in the stretch-film market since ’94, installed the world’s first nine-layer stretch line in Belleville, Ont., in 2000. “We’ve gone from nothing to 15% market share in eight years. We’re pretty proud of that,” says Per Nylen, executive v.p. of Sigma Stretch Film, based in Lyndhurst, N.J. Most recently, AmTopp in Livingston, N.J., one of Inteplast Group's three divisions, ordered a nine-layer Battenfeld Gloucester line for delivery later this year to its plant in Lolita, Texas. .
One reason resin poundage for stretch film isn’t growing much right now is that film has thinned down. In 1985, the standard was 90 gauge (0.0009 in.). Today it’s 65 to 80 gauge. One major impact of downgauging is that it has made older lines less efficient. “Equipment that used to make 1-mil film at 3000 lb/hr is making 70 gauge today, so they have lost 30% of their machine capacity,” notes Andrew Christie, president of Optex Process Solutions LLC in Fulton, N.Y., a consultant on stretch films. The only way an older line could keep up is with a brand-new winder, but processors have tended to make such a large investment only for new lines.
Even if the film poundage is static, the number of pallet units wrapped in stretch film is still growing healthily. Not only is today’s film thinner to start with, but it can stretch farther. In 1985, it took 12 oz of film to wrap an average pallet. That number dropped to 5 oz in. ’95 and to 4 oz in 2000, a threefold increase in units wrapped for the same pound of plastic.
Pinnacle (the only stretch-film maker that would provide concrete performance data for this article) reports that its 63-gauge, seven-layer Apex film shows 360% to 370% ultimate stretch on a standard test device from Highlight Industries, a maker of stretch-wrapping machines.
That means there’s still plenty of room to downgauge further, especially in the highly layered films. “We test films and find that most have an ultimate level of stretch over 350%, but the average actually applied to pallets is probably only 165% to 180%,” says Kurt Riemenschneider, president of Highlight Industries. “In many cases. the stretch films are better today than the stretch-wrapping equipment.” Film already on the market could wrap many more pallets than it does, potentially creating even more overcapacity.
Further development in this vein was reported by Pliant at the Flexpo 2002 Conference in September in Houston (sponsored by Chemical Market Resources in Houston). Pliant said it made 1-mil monolayer blown film with up to 500% stretch in R&D to evaluate three different mLLDPEs.
Highly layered films apply only to cast stretch film for machine wrap. Blown stretch film for hand wrap has one to three layers of hexene/octene LLDPE blends with expensive cling additives that are not used in cast films.
Film with more layers doesn’t usually have more different materials. Rather, the additional layers are created in the feedblock by splitting one resin stream into thin slices stacked together or alternated with layers from a different resin stream. The technique is commonly used in sheet extrusion to get a more uniform resin distribution.
“Coextrusion of thin alternating layers can improve puncture strength,” says Cloeren’s Oliver. “Extruding metallocene resins thinner actually makes them less splitty—the same way glass, if it’s thin enough, is flexible.”
“Look at nine layers as like plywood,” says Sigma’s Nylen. “We get higher pre-stretch, puncture, and tear resistance with nine layers than with five.”
Alternating thin layers of mLLDPE also allow greater use of low-cost wide-spec or butene LLDPE and reduce the amount of mLLDPE needed. In a seven-layer film with three mLLDPE layers, the metallocene content might drop to 33% versus as much as 40% mLLDPE spread over two layers of a typical five-layer stretch film.
While there are thus good reasons for letting the feedblock create multiple layers from one resin stream, there are also arguments to be made for using more extruders. “Coextruding layers of a single resin with two extruders increases throughput of a line but doesn’t affect film properties,” explains Oliver. “A high-output line with two 4.5-in. ex truders instead of one 6-in. extruder also gives the flexibility to do complex or simple products, and temperature control is a lot easier on a 4.5-in. extruder than on a 6-in. extruder.”
Pliant’s seven-layer stretch films can be made with three, four, five, or six extruders. Its first seven-layer line in Lewisburg, Tenn., has five extruders plus a small sixth machine that extrudes edge bead out of trim waste. Pliant’s newest seven-layer line, installed three months ago, has four extruders. Predefined plugs for the feedblock allow it to make seven layers with three or four different polymers. It also uses a chill roll believed to be North America’s largest for cast stretch film. The large roll quenches the film faster, further improving puncture strength and cling, Pliant reports.
Pliant’s first high-performance seven-layer film, designated R-122, was introduced in 2001 but not fully commercialized until 2002. It was developed to improve on the strength and reduce the noise level of Pliant’s OPTX five-layer film. R-122 is a premium product with Pliant’s highest mLLDPE content (over 50%), allowing both downgauging and high pre-stretch ratios. Nonetheless, it is one of Pliant’s best selling stretch films in 51- and 63-gauge versions.
R-122’s thinness gives customers more usable footage for the same roll weight: 9000 ft for a roll of 51 gauge R-122 film and 7250 ft for 63-gauge R-122, while a standard 80-gauge roll has only 5000 ft. The 51- and 63-gauge films can contain C pallet loads (irregular unboxed load with lots of protrusions) and beat the performance of some of the toughest 70- and 80-gauge films in the market, Pliant says.
R-122 took over a year to develop because initial production rates were too slow to be considered commercial. Throughput suffered and processing was more difficult with the higher mLLDPE content, so Pliant made processing and resin formulation changes.
Pinnacle’s Apex high-end stretch film, introduced in 2000, also uses seven layers and mLLDPE to achieve thinness. “We can replace a standard 80-gauge stretch film with 63-gauge film. For light loads we can go as thin as 55 gauge,” says Pinnacle’s Rice.
Black Clawson’s seven-layer stretch-film line at Quintec uses five extruders and an Ultraflow feedblock from Extrusion Dies Industries with selector spools to change layer sequence. Black Clawson says a typical seven-layer structure might be 5% to 15% skin tack layer, 5% to 10% sub-skin performance layer, 15% to 20% inner performance/refeed layer, 40% to 50% bulk/refeed core, 5% to 10% inner performance/refeed layer, 5% to 10% sub-skin performance layer, and 2% to 15% skin slip layer.
Not all highly layered stretch films use mLLDPE. Sigma doesn’t use any in its nine-layer films, noting that TD tear strength is lower with mLLDPE than with standard hexene/octene blends. AmTopp doesn’t plan to use mLLDPE in its nine-layer films, either. AEP Industries also avoids mLLDPE.
AEP rebuilt an existing four-extruder line and added a seven-layer feedblock. Its first seven-layer product was EXRW (Excaliber Roll Wrap)—heavy-gauge, 3-mil films for paper-roll wrap, a new market for one-sided cling wrap. Protecting giant rolls of paper requires surface toughness but little stretch.
AEP’s newest five- and seven-layer films, EXP (Excaliber Plus), are high-strength films designed for downgauging on high-speed automated stretch wrappers. EXP film can wrap at speeds of up to 60 rpm, whereas 20 rpm is typical for machine wrapping and 30 rpm is considered high, says Michael Hildreth, AEP’s technical manager.
Sigma focuses on less-expensive commodity films with its nine-layer line. Its Battenfeld Gloucester system uses four extruders and a Cloeren die and feedblock. The sub-skin B, core C, and sub-skin D are split into alternating layers: A-B-C-B-C-D-C-D-A.
Non-stop operation and high uptime efficiency are critical to eking out profits in stretch film. On-line width adjustment coupled with changeable flow paths in the feedblock are essential to changing layer sequences on the fly.
Stretch-film lines are also running faster and faster to beat the competition. “A couple of producers can sustain 1700 to 1800 ft/min at 4100 lb/hr,” says Robert Moeller, product manager for extrusion systems at Black Clawson. Higher production in turn requires faster winding and more automation.
The latest stretch-film winders run at up to 1400 ft/min vs. about 600 ft/min for conventional stretch-film winders. The newest winders produce a set of six to 10 hand-wrap rolls every 50 to 60 sec, and the same number of rolls of machine wrap (with larger diameters) every 3 to 5 min, depending on gauge. Such blazing speeds require automatic roll unloading and re-coring.
At least three U.S. processors have also invested in fully automated box loading of blown film for hand wrap. AEP was the first in the early 1990s, followed by Intertape Polymer Group’s Danville, Va., plant and at least one plant of Minneapolis-based Tyco Plastics. Machine wrap, which runs more slowly, typically uses partial automation. Fully automated box loading is more common in Europe, where labor costs are higher.
In the early ’90s, stretch-film lines also grew wider to increase throughput. To reduce neck-in from very wide dies, processors use a dual-chamber vacuum box and edge pinning to hold the film against the chill roll.
Winders have also grown wider. When Black Clawson builds winder rolls wider than 120 in., it uses a two-piece core shaft with a center support. This allows a single winder with 3-in.-diam. shafts to wind a wide web at high line speeds. On the other hand, the latest winders from Battenfeld Gloucester and Davis-Standard’s Egan Div. are designed as dual winding units, each with shorter shafts that reportedly provide more stability, though they cost more for equipment and maintenance.
Neither mLLDPE nor many layers are used so far in blown stretch film, though orientation developments could open opportunities for more layers and performance. Last fall, Battenfeld Gloucester introduced an in-line MD orienter that stretches film 200% to 300%. Blown stretch-film output is typically cooling limited, but this development allows an extruder pumping the same lb/hr to produce two to three times more linear ft/hr of stretch film.
Gloucester’s prototype MDO unit uses an S-wrap of two preheating rolls, one to heat each side of the film. It also has an S-wrap of two rubber pull rolls turning three to four times faster than the preheat rolls to stretch the film. Two heated annealing rolls recover some of the stretch. Finally, two cooling rolls lock in the residual stretch.
A question mark about oriented monolayer film is the effect that high levels of pre-stretch could have on additives “blooming” to the surface of the film. Research is being done now to characterize this effect, which is well understood for multi-layer film with a surface cling layer.
Stretch-wrapped silage and large cubes of garbage are relatively new niches for blown stretch film developed by AEP, Tyco, and Sigma within the past three years. Three-layer film is preferred for silage to prevent decomposition, and the biaxial stretch gives better puncture resistance against hay stalks.
Anti-corrosion stretch wrap, called VCI (vapor corrosion inhibitor) is a new niche product used to protect iron bars and other metal products from rust. VCI is difficult to make because the inhibitor additive is corrosive.
Downgauging and sophisticated structures make today’s stretch film go farther. Pliant’s newest seven-layer line puts 9000 ft of 51-gauge stretch film on a roll, vs. only 5000 ft of conventional 80-gauge film.
Making seven-layer film with high mLLDPE content at high output rates requires North America’s largest-diameter cast chill roll. (Photo: Pliant)
Pinnacle Films makes only seven-layer, high-performance stretch films using mLLDPE. Last year it added a second seven-layer line.
High-performance seven-layer films can stretch farther than most wrapping machines can pull them, even on a load like this with protruding corners. (Photo: Highlight Industries)
The world’s first nine-layer stretch-film line at Sigma Stretch Films doesn’t use mLLDPE. Its extra layers create a commodity film less expensively.
Automatic core loading, roll unloading, and boxing is more prevalent in Europe, where labor costs are higher. (Photo: SML)
Simulation can determine whether a die has regions of low shear rate and shear stress on the metal surface where the polymer would ultimately degrade, and can help processors design dies better suited for their projects.
In pipe extrusion, selecting or building a complementary set of tooling often poses challenges due to a range of qualitative factors. Here’s some guidance to help you out.
Feeder performance is crucial to operating extrusion and compounding lines. And consistent, reliable feeding depends in large part on selecting a feeder compatible with the materials and additives you intend to process. Follow these tips to analyze your feeder requirements.
There’s a simple answer: Because all plastics are not the same.
Plastics processors are finding applications for 3D printing around the plant and across the supply chain. Here are 8 examples to look for at NPE2024.
A collaboration between show organizer PLASTICS, recycler CPR and size reduction experts WEIMA and Conair recovered and recycled all production scrap at NPE2024.
Driven by brand owner demands and new worldwide legislation, the entire supply chain is working toward the shift to circularity, with some evidence the circular economy has already begun.
Dear Plastics Technology Audience Member:
Starting on Thursday August 8, 2024, PT will begin “gating” its premium content, asking all new website users to provide some information about themselves — name, title, employer, email address — before they are provided free access to the content.
We are doing this because the ways PT’s audience finds and accesses our content is changing. Google’s search algorithms, increasingly, make it difficult to connect PT’s content with the people who might make use of it. On top of that, generative AI like ChatGPT is serving up PT content to internet users without attributing that content to PT.
As a result, it has become increasingly important for PT evolve its audience development strategy and learn as much as possible about who is accessing our content, what content they are accessing and how they are accessing it.
With this audience development strategy, we hope to do two things:
PT plays a distinctive role and has earned a place of esteem within the focused and specialized industry it serves. Large developments in the media landscape are forcing us to change the way we communicate with our audience. We are confident that our audience values the role PT plays in their professional lives and will join us in this effort to stay connected to them.
We thank you for your continued interest in and support of PT and welcome any questions you might have about the brand’s new content gating strategy.
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