Shrink Sleeve Technology

To begin, what is sleeve labeling?

The broader category of sleeve labeling is comprised of three types of sleeves. The first is stretch sleeves, which are LDPE films that are formed into a tube and then stretched and pulled over the container (Figure 1.1). The stretch in the film is what allows it to form a tight fit onto the container. Stretch sleeves comprise a very small portion of the sleeve label market, and these sleeves are typically found on containers with few contours or shapes.

The second sleeve labeling category is generically known as machine direction orientated (MDO) sleeves and encompasses both R.O.S.O.™, or roll-on shrink-on, and roll-fed-shrink or roll-applied-shrink technologies. This roll-fed or MDO shrink label material is applied in one of two ways: R.O.S.O.™ is Figure 1.1 The process of stretch sleeve labeling © 2017 Accraply, Inc. applied directly to the container in the same fashion as a traditional wrap-around (or roll-fed) label would be applied (see Figure 1.2). It is unwound and wrapped around the container, joined with an adhesive, solvent, or ultrasonic or laser weld.

Following application, the product travels through a heat tunnel to shrink the label to the contours of the container. Applied in the same way as conventional wrap-around labels, R.O.S.O.™ labels offer full coverage and up to 15% - 18% shrinkage on Figure 1.2 The process of roll-on shrink-on labeling © 2017 Accraply, Inc. a contoured container.

Roll-fed shrink (RFS) or roll-applied shrink are terms typically associated with MDO films that have higher levels of shrink, and are therefore able to be applied to containers with more elaborate shapes and contours. 

Roll-fed shrink (RFS) or roll-applied shrink are terms typically associated with MDO films that have higher levels of shrink, and are therefore able to be applied to containers with more elaborate shapes and contours.

Because of the more elaborate shapes, the containers are less suitable to act as the mandrel around which the film is wrapped in the application process. For this reason, the application process becomes more complex and requires that the sleeve material first be wrapped around a mandrel that is sized appropriately, based on the dimensions of the container that will be sleeved. It is on this mandrel that the material is welded before being dropped over the container. This more sophisticated approach is illustrated in Figure 1.3.

Figure 1.3 Roll-fed shrink film being applied to a mandrel prior to being dropped over the container © 2017
Accraply, Inc.

In summary, roll-on shrink-on labels are an ideal combination of wraparound and heat shrink sleeves
that can be used to decorate a variety of container types such as plastic, glass and metal. Moreover, it is an ideal process for high speed labeling. Individual yogurt drinks, aerosols and glass bottles are just a sampling of some of the many products that are sleeved using this type of label technology.

The third sleeve technology is heat shrink sleeve labeling, which will be the focus of this book. The heat shrink sleeve labeling process involves selecting the appropriate shrink sleeve film, printing on the film, forming it into a sleeve with a welded seam and then cutting the sleeve tube to the required length, dropping it over the container and then shrinking it through a heat tunnel.

Shrink sleeve labeling remains the dominant sleeve technology globally. It comprises over 80% of the sleeve market and continues to grow. It remains one of the fastest growing of all the labeling technologies.

Foundationally, the shrink sleeve labeling process centers on the heat shrinkability of specific films (which will be discussed in detail in this book), with the printing process typically taking place on the inside of the film rather than the outside. The printed label web is formed and sealed into a sleeve with a seam, and it is then collapsed and rewound. The seamed sleeve is cut to the required container length and applied over the container, either manually or automatically, with the sleeved container then going through a heated shrink tunnel. We illustrate this multi-step process in Figure 1.4.

As can be seen, the shrink sleeve process starts with the container at the top left-hand side of the figure. We select the type of film we will use, and we then proceed to the pre-press operations. Because the printed image needs to be shrunk in the heat tunnel, the pre-press image must be pre-distorted, which we accomplish using pre-press software, so that the final decorated container image ends up correct. The pre-press technology we use to accomplish this is sophisticated, and it is central to achieving an optimal three-dimensional image on the shrink sleeved container.

As we move along the diagram to the printing process, we must be very mindful of the inks we select to accommodate for the heat that we use to shrink the sleeve. The printed sleeve web is then slit, slightly oversized, into the individual container circumference widths. From the slitting process, the slit, printed web is formed into a sleeve, or tube, with an overlapped joint on a seaming machine. Finally, the sleeved film is collapsed, inspected, and rewound for shipping to the sleeve decoration plant.

Once the sleeved film arrives at the sleeve decoration plant, we will unwind the film back to a tube, cutting the sleeves to the appropriate container depth, and then the sleeve will be dropped over the container using manual or automatic application. Once we have placed that sleeve on the container, it will pass through a shrink tunnel, and upon exiting the tunnel, we will have our finished product – a shrink sleeved container. We will examine each of these stages of the heat shrink sleeve labeling process in detail in this book.

THE INTRODUCTION AND EARLY GROWTH OF SHRINK SLEEVE LABELING

Where did shrink sleeve label technology start? Shrink sleeve labeling hails from Japan, more specifically from the Fujio Carpentry Shop. Introduced in the 1960s, the earliest shrink sleeve example was;

SHRINK SLEEVE TIMELINE

•• 1965 - First use of shrink sleeves as labels by Fujio Carpentry Shop

••1967 - Fujio Carpentry Shop changes its name to Fuji Seal Company

••1970s - Shrink sleeves started to be used in Europe for promo.tional twin packs

••1980s - Japan introduces single product shrink sleeves to Europe and North America

••Mid 1980s - Large-scale entry of shrink sleeves into the packag.ing market

••1995 - First full length sleeving of narrow neck bottles

••1995 - First application of translucent full length shrink sleeves

••1996 - First use of steam for sleeving

••2003 - First ever sleeving of Coca-Cola glass bottles

••2006 - First introduction of recyclable shrink sleeves for use on PET containers

Figure 1.5 Evolution of shrink sleeve technology. Source: Sia Consulting

Functional in nature: it was a means of providing tamper evidence when sake changed its packaging from wooden barrels to glass bottles. This change led to the introduction of the first tamper evidence seals using PVC film. From the early example that the Fujio Carpentry shop – now Fuji Seal Company – produced for sake bottles, we have seen the shrink sleeve industry evolve and change with the demands of the market (Figure 1.5). 

Figure 1.6 Some of the many different shaped bottles that can be decorated with shrink sleeves © 2017 Accraply, Inc.

The 1970s marks when shrink sleeve labeling expanded outside of Japan to parts of Europe, but it was not until the 1980s that shrink sleeve labels saw rapid growth in Europe, followed by an entry into the North American market as well. By 1995, the shrink sleeve labeling industry realized significant advances, including the ability to apply shrink sleeve labels to full-length narrow neck bottles and containers of different sizes and shapes. Just one year later in 1996, the industry saw yet another advance – the use of steam as a heat source for shrink sleeve finishing. Greater concerns about preserving the environment led to the development of the first recyclable shrink sleeve label in 2006, yet another example of the industry innovating to meet the evolving needs of the market.

In recent years, we have observed the expansion of shrink sleeve labeling beyond just high volume applications. Digital pre-press has brought greater levels of sophistication and technology to shrink sleeving, and as a result, we have seen narrower mid-web presses – rather than just wide-web presses – getting in on the action. Furthermore, there have been improvements in flexo, UV inks, LED UV inks and digital printing technologies. With these advances, converters are now able to ask the question, “How can we produce sleeves on the technology that we’re using now?”

The future for the shrink sleeve industry appears especially bright. We are seeing advances with narrow- to mid-web presses for short runs, and we are seeing advances in application machinery and more efficient lower speed machinery, all of which contribute to further growth in this exciting industry.

SHRINK SLEEVING TODAY

The advances in the shrink sleeve market have taken product decoration to an entirely new level. What we see in the market today is high quality, full body container decoration that maximizes branding real estate on the container. It offers the decoration of complex and intricate shapes (Figure 1.6). Additionally, shrink sleeve labeling has expanded to cans, providing smaller beverage customers with a more cost-effective option to ordering vast quantities of Figure 1.7 

Other advances include the incorporation of tamper evidence into the sleeve and providing hidden coding inside the sleeve as well. Finally, contemporary shrink sleeve labels may allow for reduced wall thickness of plastic and glass bottles and increase container strength and rigidity.

Generally speaking, shrink sleeve films are durable, abrasion resistant and waterproof – the image is printed on the inside of the sleeve, as mentioned – and therefore make shrink sleeve labels a more and more compelling product decoration solution today. 

SHRINK SLEEVE PRESENCE IN THE MARKETPLACE

We need not go far to encounter shrink sleeve labels in the marketplace today. Figure 1.8 shows the key categories where we see shrink sleeve labels in order of market size, and it is no surprise to see that beverage, dairy and food are the key industries where shrink sleeves are most widely used. What we observe as markets advance in their adoption of shrink sleeve labels, however, is that brand owners in categories such as detergents, cosmetics, pet food, paints and other consumer goods begin to adopt these labels as well. It is fascinating to observe the breadth of container profiles that shrink sleeve labels decorate in the marketplace: containers with narrow necks, concave shapes, convex shapes, and even bottles with multiple contours. Shrink sleeve labels have unleashed new levels of creativity, and the potential for uniquely shaped containers paired with eye-catching designs is almost limitless.

SLEEVE LABELS BY APPLICATION

1. Beverage - Energy drinks, juices, spirits, beers
2. Food - Dairy products
3. Toiletries, Health and Beauty
4. Household cleaning products - Detergents, soaps, cleaning agents
5. Pharmaceutical and Neutraceutical - Product safety and tamper protection
6. Packaged consumer goods/Retail

HOW SIZABLE IS THE SLEEVE LABEL MARKET?

To provide some context for how significant in size the sleeve market is relative to other types of labels, see Figure 1.9. As noted in the graphic, the sleeve label market is steadily approaching one-fifth of the total world label market for all types of labels.

Self-adhesive (or pressure-sensitive) and wet glue labels are the largest global label types by volume at 36 and 39 percent, respectively. However, when the Westernized markets are examined more closely, we find that self-adhesive labeling is around 42 to 43 percent of the market, with wet glue comprising some 32 to 35 percent. Shrink sleeve comprises a greater percentage of the total market when we examine specific geographies.

For instance, Asia, and more specifically Japan, is the largest market for sleeving as it invented the technology and is to this day at the farthest point of the adoption curve.

The annual growth forecast for sleeve technologies is currently 4.5-6.0 percent per annum in the latest study that AWA published in mid-2016. A report published in December 2016 by Persistent Market Research (PMR) indicates that the sleeve market is showing annual gains of 5.2 percent,of between 3.5 and 6.0 percent every year for the past 30 years - and forecasts tell us that we can expect this trend to continue for years to come.  

Taking a deeper dive now into sleeve label data, we begin with an approximation of the size of the total market, which is estimated by AWA to be 10,500 million square metres of label stock. Shrink sleeve technology dominates the total sleeve labeling market at 87 percent of the market, stretch sleeve comprises nine percent, and R.O.S.O.™ comprises the balance. The annual growth forecast for the sleeve technologies is somewhere between 4.5 and 6.0 percent per annum presently, making sleeving the fastest growing of all the labeling technologies.

GLOBAL GROWTH PATTERNS AND TRENDS
Where are the major global markets for sleeve label technology? We already know that it was invented in Japan, and as we observe in Figure 1.10, the Asia Pacific market continues to be the dominant user of this technology by a significant margin. This region is also estimated to register the highest CAGR, largely attributed to the mounting demand for beverage and packaged food in China, India and ASEAN countries.

As was mentioned earlier in this chapter, shrink sleeves entered the European market shortly after penetrating the Asian market, and Europe accounts for some 20% of the world label market today.

Figure 1.10 The global sleeve market. Source: AWA 2016 Global Sleeve Label Market Study

Figure 1.11 The shrink sleeve market in the USA. Source: industry estimates

European sleeve labeling growth is forecast to be somewhat uneven over the coming years.

North America followed Europe’s lead with shrink sleeves several years after the technology took hold there, but the diffusion and growth in North America happened at a consistent rate. Still a slightly smaller market than Europe, North America now has multiple market players and is forecast to gain further momentum with future manufacturing investment.

Finally, Latin America and some parts of Africa are the most recent to adopt shrink sleeve labeling technology. The growth of the market in these regions is expected to be somewhat sluggish between 2017 and 2021.

With the market penetration of shrink sleeves in Asia Pacific being very high, the industry has its sights set on achieving the same level of penetration in Europe and North America as in Asia Pacific. To provide some context for the growth rate of shrink sleeves in North America, more specifically in the United States, Figure 1.11 (derived from industry sources) illustrates the size of the shrink sleeve market in the year 2000 and again in the year 2014. In this 14-year period, the shrink sleeve market grew by almost a factor of ten!

In looking at the historical and forecast growth of the global sleeve label market to 2020 (Figure 1.12), we observe that heat shrink sleeve labels (the blue bars) provide the dominant sleeve label technology growth. The stretch sleeve growth is shown in red, and the Roll-on shrink-on (R.O.S.O.™) and other technologies are the green bars at the top. With projected sales of over 10,500,000,000 square meters by 2020, heat shrink sleeve labels are the focus of the labeling industry for very good reason. 

SLEEVE PRODUCTION

In order to produce a shrink sleeve decorated container of the highest quality, we must understand the various production stages, from origination and pre-press through printing, slitting, tube forming, tube application and shrinking to achieve a tight fit on the container. These stages are summarized in Figure 1.14.

A key challenge associated with shrink sleeve decoration is the origination, or the design and image preparation. The origination must be created with an element of distortion that predicts the level of shrink such that when the printed film is shrunk onto the container, it will appear proportionate and not misshapen (Figure 1.15). The pre-press step of the shrink sleeve process was therefore complex, labor-intensive, and it required plenty of trial and error, with designs created two-dimensionally in anticipation of how they would shrink onto a three-dimensional object. 

Fortunately, advances in pre-press software technology provide users with realistic results, demonstrating how the artwork will distort during simulated trials and what the finished product will look like, sparing converters the hours and hours of trial and error that once used to be a key component of the shrink sleeve process. We will discuss this in greater detail in Chapter 3.

Following our discussion of origination and pre-press in Chapter 3, we will discuss the printing and the ink selection processes in Chapter 4.

Flexography is forecast to be the most preferred printing technology in the coming years, but rotogravure and offset lithography are still widely used. Digital printing has gained increased popularity as of late, both with toner and inkjet technologies. In a similar vein, ink chemistries vary and will behave differently based on the materials on which they are printed. The ink chemistry needs to 'stay' with the film as the film is shrinking in the shrink tunnel.

After printing, the web will be slit to the correct width, where it will be ready to be formed, or seamed, into a tube. Seaming is the process of welding the edge of the shrink materials together with a solvent to form the sleeve before it is cut or rewound onto a roll. Seam location will vary from one shrink sleeve to another, depending on variables like container shape and style, automatic or hand application and artwork design. Slitting and seaming has its own terminology, such as ‘layflat’, ‘slit width’, ‘seam location’, ‘solvent width’, ‘U-fold’, ‘skips and voids’, and ‘solvent control’. All of these terms, together with the technology of folding and forming, rewinding and oscillation, monitoring and inspection, are discussed in greater detail in Chapter 5.

Application and heat shrinking are the final links of the shrink sleeve chain. All of the chapters up to this point will look at how to produce a high value, high quality label. However, it is during the application part of the process where some of the key challenges lie, making this stage as important as the previous steps. We will also introduce some new terminology, like ‘overlap’, ‘repeat length’, ‘cut length’, ‘clear area’, ‘curl back’, and ‘smiling and frowning’, all of which require some depth of understanding before examining the various types of sleeve application machinery, sleeve manipulation solutions, and shrink tunnels and accessories. All of these aspects will be covered in Chapter 6.

NEW DEVELOPMENTS

Innovation continues to expand and develop the shrink sleeve label market. Some recent advances include color change and glow-in-the-dark sleeves, limited edition and personalized sleeves, hidden prizes and coupons, multipacks, biodegradable films and co-extruded films, lightweight containers (for cost-saving purposes), microwaveable sleeves, and advances in shrink tunnel technology. Additionally, the sleeve industry has introduced full-length container decoration on complexly-shaped containers, combined body label and tamper evidence, 360-degree decoration, a wide range of finishes such as matte, gloss and pearlized, reduced wall thickness of plastic containers, and UV barrier properties.

To summarize, the shrink sleeve industry remains as dynamic and vibrant as ever. With so much growth potential in virtually every part of the world, the opportunities that this label technology presents to converters – not to mention the marketplace in general – are virtually limitless. Brand owners are eager to employ this technology to share their brand’s story with consumers at the point of sale, and consumers are drawn to the shapes, designs, colors and textures that shrink sleeve labels bring to life on the containers of products that consumers purchase. Shrink sleeve labeling will continue to inspire the market for decades to come.

Figure 1.4 The complete shrink sleeve process, step by step © 2017 Accraply, Inc.

Figure 1.12 The historical and forecast growth of the sleeve label market to 2020. Source: AWA Global Sleeve Label Market & Technology Review 2016

SLEEVE LABEL RAW MATERIALS

••PVC – Polyvinyl Chloride

••PETG – Polyethylene Terephthalate Glycol-modified

••OPS – Orientated Polystyrene

••OPP – Oriented Polypropylene

••PE – Polyethylene

••PLA – Polylactic Acid

KEY STAGES IN SLEEVE PRODUCTION

1. Origination and pre-press
2. Web-fed printing of film
3. Slitting web to label width
4. Forming slit web into a tube and seaming
5. Re-winding of seamed tube
6. Cutting tube to required depth and then applying to product container
7. Heat shrinking of film on sleeved product or container to a tight, shaped fit

Figure 1.13 Films used for heat shrink labeling

Figure 1.14 Key stages in sleeve production

ORIGINATION AND PRE-PRESS
••Predict the level of shrink

••Digitize the subsequent distortion

••Provide a 3D preview

••Display the artwork distortion on the sleeve

••Pre-distort the artwork to compensate for production

Figure 1.15 Distortion is the major challenge