SMI Labels and Packaging Materials

Thursday, April 4, 2019

Changing world of labelling technologies

Papyrus


Labels in today’s time have become the face of a product and gained immense importance being the first point of contact between the manufacturer of a product and its end user. It maybe a piece of paper, film, cloth, metal or another sheet of material on which information about the product is written, printed etched or embossed and the label so created is affixed to the package or the product. At times, information is printed or engraved directly on the product to perform as a label. Systematic and conscious writing started in the middle of the 4th millennium B.C. and with it started a demand for improved writing materials. The first written words are found etched on stone, later the Egyptians invented papyrus or parchment from which the name paper is derived. Papyrus was an early nonwoven fabric. Reeds 12 to 20 feet high and 3 inches in diameter were cut in thin slices, laid side by side, and beaten with a mallet, after these were brushed with a floor paste, fresh slices were placed at right angles and the beating was repeated, the finished papyrus, was luminous brown. Before the invention of paper in A.D. 105 by Tsai-lun, a minister of agriculture in the court of Ho Ti, the Chinese wrote on silk and thin fibres of wood and grass. Woodblock printing, which is a technique for printing text, images or patterns on paper, originated in China around 200 CE (Common Era, a modern alternative for AD). It is process by which blocks of wood are chiselled to create images that are inked and pressed on to paper to transfer an image of text. The earliest use of paper as packaging was in Egypt during 1035 when it was observed that vegetables, spices and hardware were wrapped in paper while selling. In middle of 15th century a German goldsmith Johannes Gutenberg assembled the first mechanical printing press that would apply ink on a block and press it on paper or cloth to transfer the image. The earliest labels designed in Europe were simply small pieces of parchment tied with a string to the neck of wine bottles, even though the Egyptians had started using gum Arabic from Accacia trees, or resins from trees for various decorative uses including pasting labels on to products. By 1700, labels started being designed by engraving on stone, ink applied on it and a roller was used to transfer the image on to paper. By 1798 Lithography had been invented and labels started being made in large quantities evolving further to be produced in colour with flat bed printing. This was the initiation of what is today known as wet glue labels. The wet glue labels have been used till the beginning of 20th century after which other forms of label production surfaced. Various printing technologies to print are employed, these include letterpress, offset, Rotogravure, Flexo, Screen Printing, Digital printing, etc. This article does not intend to dwell on the technology of these processes but on the changes that came about in evolution and usage of diverse label technologies.

Wet Glue Labels

wet glue Label applicator
For hundreds of years paper labels printed with different printing process like lithography, letterpress, screen, offset, etc. have been in use by affixing with a variety of adhesives. These varied from floor pastes, to fish glues, gum Arabic, animal glue, etc. This was majorly for manual labelling applications. With the development of starches and dextrin-based adhesives, these started being extensively used for labelling. As volumes started to grow steadily, need was felt for automatic high-speed wet glue labelling where fast drying was a challenge. At this time, high solids dextrin based quick drying adhesives were successfully developed. The automatic label applicator industry developed and prospered. Till date many wet glue beer and liquor labels are still applied with dextrin-based adhesives. These do have a shortcoming of shifting on high speed applicators while packing when still wet, shrinking or warping in presence of moisture or falling off when chilled. Synthetic adhesives with over 50% solid content have also been developed to overcome these issues but accurate placement and the labels shifting due to being packed while still wet is not aesthetically approved in modern retail. These adhesives still contain 50% water to dry. Also, the need for clean room production facilities needed, has now made wet glue labels a deterrent.

Self-Adhesive Labels:

R Stanton Avery
A story that led to a development of self-adhesive or pressure sensitive labels given below, changed the way labels would be known eventually:
Living in a rented chicken co-operative, a young American poverty-stricken man in his early 20s worked as a night clerk to fund his education. He stopped school and went to live for a year in China, where he gained experience working with a printing press. He returned to USA after the year, graduated and desperately tried his hands at various business options, he even sold smoked bananas! He then took on a morning job at a flower shop and later in the day started to experiment on various small things in a 100 square foot place nearby. He came up with the idea of making self-sticking labels. With the printing press experience behind him he saw the vision to start his new venture. With no money of his own, he borrowed 100$ from his fiancĂ©e, Dorothy Durfee, who later became his wife, to invest in his start-up business. Using a washing machine motor, parts of a sewing machine and a saber saw, he developed the world’s first self-adhesive label cutting machine. In 1935 he started his maiden venture Kum-Kleen Adhesive Products Company which would be the mother enterprise of the world’s largest labelstocks company Avery Dennison Corporation and this poor man was "Ray Stanton Avery!".

This pioneering development made by him, evolved over the years with need of labels to be made in roll form to dispense automatically on faster packaging lines as PSA labels make an instant bond on application and do not need drying time. Initially the label face used was only paper, but the release liners needed to be developed further to provide for easy release and dispensing. Over the ensuing years, silicone coating and their chemistries were worked upon to reach perfection in dispensing the labels on high speed packaging lines. Adhesive technology also advanced to adhere to various substrates, withstand varied application or service temperatures and diverse weather conditions. The face material also has now a wider variety with many filmic and non-conventional face materials like cork, fabric, and foil being used. The printing and converting over the years have also undergone a sea change from simple flat bed printing to now advanced flexographic printing in combination with multiple printing processes and decoration processes like lamination, varnishing, cold foiling, hot foiling, embossing etc. All these processes, inline in a single pass. The pressure sensitive labels have evolved in different tangents to produce barcode labels, RFID labels, Security labels, removable labels, etc.

Screen printed labels and containers;

Though types of labels and not printing technologies is the point of discussion in this article yet screen printing gains importance as it evolved to be used as a stand-alone label on products without any carrying substrates. For this reason, the origin of screen printing is dwelled upon. The idea of screen printing originated from stencilling used in Japan when designs were cut in banana leaves and ink was pushed through the holes to transfer images to substrates. In the start of 20th century when silk screen became available the screen printing evolved further. Later as the process developed, Nylon or Polyester bolting cloth of different mesh was used to make printing screens on wooden or Aluminium frames. As chemical evolution took place Chromates like Potassium Bichromate were dissolved in a PVA solution and coated on the screen, dried in dark and then placing the negative or Positive of the design on the screen was exposed to UV lights. Earlier the exposure was done in Sun light, but later high intensity lamps were used. The screen was then washed so that the parts that were exposed became insoluble and the rest of the design opened. Using a squeegee or a blade the ink is pushed on to the substrate forming a perfect image. Later photo sensitive films became available eliminating the need for the bichromate chemicals. For more colours, multiple screens are used. Screen printing directly on products eliminated the imperative use of paper as substrate as machines were developed for printing directly on round containers. This enabled 360 degrees print visibility on the products. For short runs of paper labels screen printing was also used. With increasing demand for attractive labels and development of increased decoration capabilities available on flexo label presses and alternate printing technologies, screen printing on containers lost the market substantially in product labelling segment.

Wrap around Labels

Wrap around labels
Once the idea of 360 degrees print visibility, people started to use offset printed paper labels to manually label round bottles using starch-based adhesives. The size of the labels was kept such that the label went all the way around the bottle. These labels worked well on glass bottles but when it came to HDPE plastic bottles, being a low energy surface, the adhesive would not anchor on and with time the labels tend to fall off. This problem was initially over come by increasing the length of the label such that there was an overlap after wrapping around of the label and the bond was between paper to paper. Label printing evolved to be produced on flexo presses with capabilities to decorate them in line both in paper and films. With filmic labels being made available in roll form it enabled their usage on automated packaging lines and label applicators for wrap around labels as well. The label applicators for wrap around labels are fitted with hotmelt adhesive dispensers to glue and form instant bonds at label ends in high speed packaging lines. Wrap around labels are now being extensively used for beverage bottle labelling.

Heat transfer labels

Heat transfer is a labelling technology branded as Therimage, was developed in the 1960s by Dennison manufacturing company based in Framingham USA, in which reverse printed labels on film or paper are transferred off on to a container using heat and pressure. These labels are printed by rotogravure printing process and transferred with help of Therimage heat transfer applicators. Once applied, the labels are permanently adhered to the container. Dennison Manufacturing begun in 1844 by Aaron Dennison, a Boston jeweller, it grew into a large enterprise offering from graphics and packaging, to variable imprinting and automotive, to home and office products. In 1990 Dennison manufacturing was merged into Avery and the new entity came to be known as Avery Dennison Corporation. The stationary and graphic business became the stationery division of the new entity but the Therimage division was sold to MCC (Multicolour Corporation) It is believed that this division was not grown further as it was in contrary to the vision of Stan Avery, the man who invented pressure sensitive labels. In recent time we see this labelling technology being adopted by some companies as it does away with the release liners and the label can be recycled along with the plastic container. Pens and other small radius containers use this technology because a decorated image is transferred without the problem of edge lifting as in self-adhesive labels on tightly curved containers or products. The technology provides a seamless, aesthetic, “no-label” look and offers 360 degrees print visibility.

Shrink sleeves

Shrink sleeves surfaced many years ago but they started being used as 360 degrees visible labels due to pioneering development done by Fuji Seal of Japan in 1965. Shrink labels are printed on a specially formulated film with unique characteristic, that shrinks on application of heat to form and fit to the special shape and contours of the product, container or a package. Each design is unique in creation as a special software helps create the prepress to account for distortions and make the label, legible, attractive and in symmetry with the shape of the package. Since the printing is done on the reverse, it remains protected under the film. The shrink sleeve market started to grow at a faster pace only in the 1980s. In USA its growth from 75 million dollars in the year 2000 to 700 million dollars in 2014 is proof of this technology’s success. According to market report by “marketsandmarkets” the global market size is projected to reach USD 13.20 Billion by 2020, at a CAGR of 5.5% from 2015 to 2020. The Asia-Pacific region accounted for the largest share in terms of value, followed by Europe and North America in 2014. In recent years, the Asia-Pacific region has progressed significantly in the shrink sleeve & stretch sleeve labels market, which primarily includes emerging economies such as India and China

In Mold Labels


Paper or film printed labels (mostly filmic) are placed inside the moulds during the molding process. After placing the label, molten plastic is injected into the mould. On cooling the label is fused with the resin, takes the shape of the so molded container and becomes an integral part of it. The labels referred to as IML can be printed and decorated by any of the processes i.e. Offset, Flexo Gravure or digital. The end result is a highly decorated container. These IML applied containers are used for Ice cream, butter, paints, food packaging, etc. According to research firm MarketsandMarkets, the global in-mold label (IML) market is projected to grow from $2.58 Billion in 2015 to $3.23 Billion by 2020, at an estimated CAGR of 4.54%. It is the fastest growing segment amongst the various label segments.


Digital printed labels

The history of digital printing is rather short. Xerox introduced photo copying in 1960 but it remained a document managing equipment company for long. In 1977 Benny Landa known as father of digital printing setup his company Indigo to produce faster photocopying machines. He soon realised that the ink used in photocopying machines could be used in printers. Developing the idea further he launched the world’s first digital colour printer to make computer to print possible. Digital printing captures images from a matrix of dots, called pixels in a process called digitising. These digitised images are then used to control the deposition of ink, toner or exposure to electromagnetic energy to reproduce the data. In 2001 Benny Landa’s company Indigo was acquired by Hewlett Packard Company (HP). The digital printing market according to Smithers Pira has been growing steadily ever since to reach a figure of 120.9 billion US Dollars in 2012 and estimated to reach a whopping 387 billion by 2024. Digital printing is broadly categorised in two processes i.e. electrophotography or dry toner-based technology and Inkjet printing using liquid inks. Also, as per Smithers Pira report, Electrophotography is the major contributor to the digital market. However, inkjet is the sector which is growing more rapidly. Inkjet is forecast to overtake electrophotography after 2019 and by 2024 inkjet will account for 56% of the value and 53% of the digital print volume. The digital printing technology will spread to fields of labels and packaging. Cartons, rigid packaging, flexibles, metal and corrugated are sectors that will largely take up digital production method.

Helmut Schreiner
Digital printing is now recognised the most disruptive technology in the field of printing. According to Vandagraph report about its impact on labels industry, “Digitally printed labels is a market seen as already mainstream, although with plenty more scope for growth. Narrow web inkjet presses are already used for labels and packaging options including small folding cartons, flexible packaging, pouches and sachets, form-fill-seal and blister packaging. European Label Industry Association Finat has also revealed that European digital label press installations overtook conventional press sales for the first time in 2017. Digital printing is the future, with continuous growth it is already registering a faster CAGR than other technologies in many geographical zones around the world. In 2013, the author while interviewing Helmut Schreiner, former Chairman of Schreiner Group had asked him about the new label technologies impacting PS labels, his reply was, “All technologies will coexist. The customer today is very knowledgeable and knows about the increasing number of options available. Labels are a necessary decoration for any product, innovation is the need of the hour. For example, one can design a label such that if you touch a label, it plays music.” He added, “I am a fan of innovation. If everyone sells tomatoes, I would like to sell peaches!” Adding a word of caution, “Printing directly on products is dangerous, it reduces cost and could decrease the demand of labels”. He was hinting at Digital printing directly on products.

Written by Harveer Sahni Chairman Weldon Celloplast Limited, New Delhi India April 2019  

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