Introducing Pinch Closure Bags

Polypropylene BOPP bags have revolutionized pet food packaging. Now comes new technology that is revolutionizing BOPP packaging. The pinch closure bag is produced on newly developed dedicated machinery that delivers customized step cut ends, a single folded closure that translates into a host of marketing and product performance improvements – even over popular BOPP packaging.

Unique EZ-open features

Unique EZ-open features

An alternative to a sewn closure. Anduro’s pinch bags offer pet food, as well as manufacturers of many products, an alternative to traditionally sewn closures, supporting easy-open features. Bags are delivered to the customer with one endsecured, or “pinch closed,” during production; the other end is open, either step cut or flush cut depending on customer requirements. Unique EZ-open features can be designed in to meet a variety of customer packaging requirements.

Enhanced brand recognition. A pinch bottom presents a broader bag base, substantially enhancing product identity exposure on the retail shelf.

Pinch bottom enhances brand recognition

A stronger poly bag. The pinch bag production closure is stronger than previous generation poly bags, enhancing resistance to leaks and infestation. The pinch bag delivers a stronger barrier against moisture and humidity and other atmospheric conditions that can compromise the bag’s contents, a feature particularly important to pet food producers.

Resistant to breakage. Because the bag is more secure it is also more resistant to breakage. Pinch bags simply perform better: during filling, in storing, in transport, in the retail environment and for the end user. Pinch bags perform like paper bags on existing heat-seal equipment filling lines. 

Anduro continues it industry leadership with new refinements in raw materials to allow for hot-air welding, with an improved co-efficient of friction (COF) for impeccable performance on all types of filling equipment, and now with the technology and expertise to create pinch bags, the next revolution in BOPP packaging.

El Refugio: A Beacon of Light for the Imperiled Children of Honduras

An open letter from Marc Datelle, CEO, Anduro Manufacturing 

As an employer in San Pedro Sula, Honduras, we are shaken by much of the news related to that country these days, especially the news relating to children. However, there are people and projects afoot in that country to provide succor to children in harm’s way. We are particularly proud of the work that is being done by El Refugio, a home for children in severe and imminent danger. El Refugio accommodates more than 75 children, from ages three to 18, who have been referred by the Honduran Children and Family Institute and the area’s juvenile court. More than simply a refuge, El Refugio is an opportunity for these youngsters to play and learn, to enjoy childhood and grow into independent, productive adults. The four-acre site consists of four houses, an elementary school, a library, two workshop buildings, an arboretum and covered sports court, all surrounded by playgrounds and a large garden. The facility also houses a bakery, a welding shop, a sewing room for making clothing and a beauty salon. All is designed not only to provide the children with ways to develop meaningful skills, but to offer them an enriching developmental experience. Through a variety of programs and a skilled, dedicated staff and volunteers, El Refugio provides the children an excellent academic and vocational education, as well as teaches them critical life skills. They learn English, a key to additional education, including college, and a meaningful job and life following their education. 

When we purchased our factory in San Pedro Sula in 2009, we were introduced to El Refugio and the people who tend to its operation, including Jack Ward, chairman of the Honduran Children’s Foundation, which sees to its funding and which I am proud to serve as a member of its board of directors. Anduro has bought computers and software for the school, and we continue to provide ongoing support, everything from fabric to beauty supplies, from soccer balls to medical supplies. We have employed several El Refugio students as interns and plan to hire our first two El Refugio graduates later this year. 

We wanted you to know that there is good work being done on behalf of the children in harm’s way in Honduras. We invite you to learn more about El Refugio at And if you find the work of El Refugio as important as we do, we’re sure a donation would be heartily appreciated. For that you can contact Jack Ward at the Honduran Children’s Foundation, Inc. Phone: 770-980-7920; Email:

Insights: on WPP BOPP Packaging 

Then and Now - In just a few years, the WPP BOPP packaging landscape has changed dramatically – and so have the concerns of WPP BOPP bag buyers.

In and around 2004, Americans working in China for global agricultural economics leader Cargill learned of a packaging material that was far superior to the multi-wall paper bags used for their animal nutrition products in the United States. Short on resources for manufacturing paper, the Chinese constructed bags from raffia, a fiber particularly good for weaving. 

The idea of making bags from woven polypropylene (WPP) was initially not well received by U.S. packaging producers, whose fortunes were tied to the traditional paper sacks. The early WPP inroads with animal nutrition producers were made by rogue independents who imported the bags almost entirely from a single Chinese firm, which made WPP bags and laminated them with biaxially oriented polypropylene (BOPP). 

The advantages of WPP BOPP bags, both in terms of integrity and graphic appeal, were so apparent that the largest suppliers of animal feeds and pet care products moved quickly to convert. In doing so they learned of additional advantages: WPP bags occupied about a third of the space of multi-wall paper, they virtually eliminated spoilage and were more weather-resistant. 

The rest, as they say, is history. Cargill led the way, mandating conversion for all their producing plants. Others followed, and if anyone was hesitant, retailers like Wal-Mart eventually made the decision for them, refusing to carry products in breakage-prone packaging (a decision influenced by a slip-and-fall lawsuit, the incident caused by spilled pet food from broken paper packaging). 

In those early days, the concerns of bag buyers centered mainly around supply capability, quality and price. In an effort to protect U.S. packaging manufacturers, including some initial ill-fated efforts to make woven bags, the federal government imposed anti-dumping tariffs, ranging from 120 percent to as high as 244 percent, on finished bags imported from China. Asian suppliers, sometimes in collaboration with their U.S. brokers, responded by opening plants in Viet Nam, Cambodia and Thailand. Even with relocated manufacturing options, delivery schedules were highly inconsistent and undependable (today it still takes 12 to 14 weeks to get bags produced and delivered from Asia).

There were problems beyond price and scheduling. The new packaging tended to slip as it moved up inclines on some filling equipment. It wasn’t as stiff as paper, so it did not perform as well on some automated hangers. The pallets from China were of poor quality and there was a problem delivering the bags flat or unwrinkled, causing additional problems on filing lines. Colors were typically printed inaccurately creating branding issues, and of greater concern, printing inks were rife with the carcinogens toluene and benzene. Environmental concerns extended to a lack of process for recycling used woven bags.

Today the market is maturing and customers are more knowledgeable. As mid-sized and small producers join the largest companies in converting to WPP BOPP, they are choosing suppliers based on their compliance with the highest standards for quality and safety in construction and print. They want a clearly defined supply chain, to be as close to the manufacturer, the actual bag maker, as possible. They want to understand the cost-risk relationship: pricing, lead times, materials, etc. They want a bag manufacturer who can not only produce to their specifications, but help them determine appropriate specifications for their applications. And increasingly, like all maturing industries, they are vetting suppliers based on their commitment to, and ability to provide, superior customer service.

Today, WPP is the rule rather than the exception for animal nutrition packaging. It is increasingly being used for pet food and pet care products, and making headway as preferred packaging for human foods, rice for example. 

This e-publication is just one part of the expanded breadth of information featured on the new Anduro Manufacturing website, activated June 1st. In addition to providing current information on the evolving packaging environment in the animal nutrition and pet care industries, the new site shares insights into the steps Anduro continues to take to meet constantly changing client demands for WPP BOPP packaging through improvements in production, shipping and customer support. To learn more about WPP BOPP packaging and Anduro, stay tuned to

Anduro has assembled an executive team of deep and varied industry expertise that ensures clients receive high-performance product supported by knowledge and committed service. 

  • As Anduro’s founder and CEO, Marc Datelle has overseen the development of Anduro as the most innovative and progressive WPP BOPP supplier. 
  • Following 24 years directing international operations for Kimberly Clark, Gil Madrid joined Anduro as president to direct company operations. He has implemented systems that allow Anduro to serve a growing number of clients with unique needs and specifications with high-performance quality product, timely delivery and support. 
  • Jon Solberg directs Anduro’s technical strategies, guiding the company in terms of new technology, package innovation, and mastery of our current process including printing and fabric production. He was on the front end of the initiative to bring WPP BOPP packaging to U.S. suppliers, and has been instrumental in the industry segment’s growth, resolving both access and product development issues for pet nutrition and pet care manufacturers. 
  • Anduro’s manufacturing facility in San Pedro Sula, Honduras, is directed by General Manager Carlos Ramirez. Mr Ramirez came to Anduro after more than 26 years overseeing large commercial construction and manufacturing projects for the Honduran government. He oversees the plant’s manufacturing and bi-lingual customer service staff who support the firm’s U.S. and Central American clients. 
  • Comptroller Jorge Morales brings Anduro more than two decades in financial management with some of Honduras’ largest banks and manufacturers, including Sara Lee and Russell Athletics. 

Anduro Manufacturing entered the market in 2009 recognizing the opportunities of the growing demand for WPP/BOPP and resolved to address the key risk issues. By manufacturing in the Honduras, a tariff-free free-trade zone, Anduro provides the ideal combination of quick turnaround and competitive pricing. American owned and operated, Anduro understands the expectations of American buyers, and have implemented policies and procedures consistent with U.S.-based packaging manufacturing. By manufacturing to the highest standards of quality and safety and delivering dependably and to specification, Anduro has earned the business of the largest and most demanding animal nutrition suppliers, including Nestlé, Manna Pro, Ainsworth and Cargill Central America. And in committing the resources to proactive client service, Anduro not only ensures meeting client expectations but helps clients find better ways to improve their packaging efficiency and performance. 


One of the main reasons feed and seed producers are moving from paper to polywoven packaging is their appeal in the retail environment. Functionally, polywoven or BOPP/WPP bags are stronger and more durable than paper, enough reason to switch. But they also print beautifully to be much more inviting to the eye of the consumer. With that added brilliance comes an additional challenge: your bag supplier must have expertise in printing to ensure the quality of the print job fulfills the capability of the BOPP bag.

BOPP bags are printed on either flexographic or rotogravure presses. These printing systems demand specific attention to key issues to ensure your bags are printing properly and consistently from the first bag to the last, and through multiple reorders employing the same artwork. There are some key steps to ensuring you and your supplier work together to produce a perfectly printed bag:

Whether you design in-house or outsource to a third party, the design has to accommodate the construction of the bag. Your graphics will travel through rotary and linear processing, so it’s important your supplier can help your design team layout the artwork so the finished bag meets your expectations. Some things as simple as where the lap-seam meets on the back panel, or how color breaks accommodate bag length and how it will be sewn, or where critical information is located. Make sure your supplier can help in the critique of the important mechanical aspects of artwork and is capable of recognizing in advance where adjustments to the artwork need to be made to accommodate the way the bag moves through construction.

Color is brand. Protecting your brand requires hitting the color target and staying on target throughout the life of the product and production schedule. The key to getting and keeping color accurate is the formulation for the ink mixing. The color should be validated by a densitometer, which measures color saturation, both in the ink room and on press. The appropriate test to ensure the right color and consistency is an Lab (L, a, b, color space) to determine color and color differences. These are systematic and verifiable methods for delivering results that your supplier should be well-versed in and prepared to deliver on.

Key to controlling color throughout the printing process is maintaining ink viscosity. Too low, and fine details are washed out; too high, and halftone dots tend to disappear. Your bag supplier should be able to demonstrate an understanding of the difference between digital color control in the ink room and on press, and be able to explain how they are going to control your color and hence your brand.

For flexographic or gravure printing, we recommend your artwork is produced with a resolution of 133 to 175 dpi (dots per inch). More importantly, confirm that your printer’s resolution capabilities can meet your designer’s expectations. Your supplier should be capable of producing color separations for gravure cylinders or flexography plates that ensure sharp and clear images and copy throughout the print run.



In the process of building your BOPP/WPP bags, printing is most important to controlling your brand, not just in a single bag run, but over the life of your order entry process. Make sure your supplier understands how your artwork lays into the bag making process and can control color and resolution quality throughout to ensure you get what you expect in every bag.


Woven BOPP bags have become the packaging gold standard for animal feeds, and increasingly for pet food. Because woven bags are so much more durable than multi-wall paper, from filling to distribution to retail and the end customer, demanding retailers, like Walmart, require suppliers who want shelf space to use woven bags. And because the graphics are so much sharper and more colorful, producers have turned to laminated BOPP packaging to be competitive in the marketplace.

The question is no longer whether or not to use BOPP bags, but how to buy them. Initially, BOPP bags came from the Pacific Rim, primarily China. And U.S. producers, unable to deal directly with Chinese manufacturers, bought their bags through brokers. But being so far removed from their sources has caused problems: with the products, because of delivery times and product quality; and with brokers, because they add a lot of cost and little or no value. Still, buying bags domestically has proven cost prohibitive, so many producers do a juggling act, accepting longer lead times out of the East through brokers and supplementing with higher-cost domestic bags when necessary.

Anduro Manufacturing, a U.S. company based in Atlanta, Ga., has structured its operation to address these issues. We manufacture our Durofab™ brand BOPP bags in the free trade zone of Honduras, home to many of the largest and most successful American consumer product manufacturers. Everything is done locally, from weaving the bag fabric to printing to assembly – a tightly controlled, integrated process. Manufacturing costs are low and bags are just two shipping days from our terminal in Gulfport, Miss. The idea is to provide the best of both worlds: favorable pricing and delivery to meet the most demanding producer schedules.


  • You know where your bags are being made. Bags coming out of Asia through a broker may have been made by several different shops; consistency can be a problem.

  • You get what you buy. Without direct contact with the manufacturer, it is difficult to ensure your bags are being made to your specifications. In particular, fiber weight may be compromised and printing inks may contain high levels of toxins.
  • You can better protect your brand. When you are working directly with the manufacturer, you can be assured of the integrity of your graphics and quality of the flexography or rotogravure printing.
  • You can ensure proper bag length. Because the automated equipment used by U.S. producers allows for very small tolerances, bag length historically has been an issue with bags made in Asia.
  • You can count on better service. With no middleman between you and your producer, you have a direct link to your bag production. Communications are simplified and problems can be resolved in real-time.


Of the many elements that go into making BOPP/WPP bag packaging, fabric weight has the most impact on price. Typically, BOPP bag manufacturers measure fabric weight in grams per square meter (GSM). For a long time, 85 GSM was the norm for BOPP bags. That has trended downward to 75 GSM; some producers are running 65 GSM or even 55 GSM bags on their filling equipment. Obviously, the lower the weight, the less fabric, and therefore, the lower your per-bag cost.

The lowest weights might run okay on manual filling lines, but most U.S. producers use automated filling equipment, and the less stiff the bag, the more challenging is filling it on automated equipment. (Some merchants also demand thicker bags.) Older swing-arm style filling machinery is particularly challenged by lower weights; if a bag is too thin, it will “creep” while in the cassette and slide out of position causing “mis-hangs.” Lower weights are handled a bit better by hangers that pick up bags lying flat.

You might see fabric weights measured by “denier,” typically calculated as square inches per pound. The different measurements can be correlated; for example, 85 GSM converts to a 900 denier.


All of these measurements and subsequent conversions can make it difficult to determine if your bags are truly measuring up to your specifications, that is, if you’re getting all the weight you’re paying for.


  • Cut a measured square (accurately) and weigh it on a gram scale. Then convert to grams/square meter to get the overall structure basis weight.
  • Subtract the basis weight of extrudate, typically 18 GSM, which is the polypropylene used to adhere the printed film to the fabric.
  • Subtract the weight of the printed BOPP film, typically 16.2 GSM (18 micron).
  • The remaining weight is
  • the fabric weight, which in this case should be 75 GSM.If you’re looking to determine weight by denier, take the actual GSM weight, divide it by 85 and multiple by 900. E.g., 75 GSM divided by 85 GSM = 88.235% X 900 denier = 794.115 denier.

Remember this is an estimate and there will be some variation – most variance will come from extrudate – but you should be close enough to determine if your bags meet your fabric weight specification.

Understanding the measurements how to convert one specification to another will help you run a more effective cost analysis, leverage your packaging spend and make a smart BOPP packaging buy.

Finishing & Packaging: The Keys to Bag Integrity & Performance.

All the good work done in manufacturing and printing your BOPP bags can be for naught if they are not finished and packaged properly. Poor finishing touches or shabby packing and palletizing will diminish product integrity and create problems in the filling process. The finishing and packaging areas most critical to ensuring your bags arrive in good shape and perform well on your filling equipment include:

Bag integrity relies to a great extent on how the lap seam is glued. Most frequently, problems have arisen where bags are stored outside in cold and dry climates. The materials get brittle and the seam is compromised. In the early days of making BOPP bags the solution was to convert from glue to an extrusion lap seam. But today improvements have been made in hot melt glues; if the manufacturer is willing to invest in a superior glue, it can be used with confidenc

While graphics typically determine a bag’s width, bag lengths often vary where gear-driven cutting systems are employed. Bags are cut according to an “eye spot,” a rectangular black bar printed on the bag that triggers the knife. With a gear-driven system, the trigger tends to gain over time, adding length to the bags. The variations create problems for automated fillers. Anduro employs a servo-motor system to control the rotary knife, wherein a sensor catches the “eye spot” and trips the knife to fire precisely at that point for a consistently accurate bag length.

Just as critical as making and finishing bags with precision is packing them in pallets so they ship and unpack without wrinkling. Wrinkled bags don’t perform well on automated filling equipment. Bags are packed manually, and packing personnel must build the stack in a jigsaw-puzzle style manner so as to ensure the bags don’t wrinkle when compressed. Once the bags are stacked properly, the pallets are reinforced with angle brackets to prevent them from collapsing and damaging the bags. At the Anduro plant, we use hardwood pallets that hold up to 6,000 bags, so shipping is cost-efficient and the bags are afforded maximum protection.

An uncompromised finishing and packing process means you receive bags with consistently accurate dimensions, including gussets and bag length, with lap seams that maintain their integrity in all types of environments, and that are not wrinkled or damaged during palletizing, shipping or distribution.