The Old and the Beautiful

Glass packaging — natural, versatile, relevant


Pop artist Andy Warhol described it as the “design icon of the decade”. The Coca Cola bottle is probably the most easily recognised packs in the world. The smooth feminine lines of the bottle were first conceived in 1916. Coca Cola, the product, as well as its pack, was being widely imitated. The simple brief to the designers was, “design a pack that a person could recognize even in the dark, or even if it is broken.”

From that time on, the Coke bottle has assumed iconic status in the packaging world. As everyone knows, the brand sells all over the world today, and has often been launched in cans and PET bottles, but affirmative research conducted by Coca Cola confirms that consumers still prefer to drink their Coke from a glass bottle!

It is natural, versatile and as relevant today as when it was first produced in ancient Egypt. What’s more, it is completely recyclable. Little wonder then that consumer research across Europe continues to endorse glass as the packaging material of choice. In short, no other material connotes quality and confidence in such measure.

Why not Glass?
Although glass as a choice for new packs is often dismissed because of its high cost of tooling up, high inventory requirements and large amounts of energy required in its production, it still rules as a favourite because of it following characteristics:
– Glass is a favourite with consumers
– Glass allows ideal manufacturing
– Glass is a sustainable and healthy material
– Glass has a long history of human use
– Glass is an ideal material for modern technology
– Glass is a natural material
The design flexibility of glass is staggering: clear, frosted or coloured, tall or small, smooth and straight or rippled and interesting. Add a multitude of decorative options and you’ve got a packaging material that can add dynamic value to a brand.
Whether you want to communicate simplicity, elegance, indulgence or excitement, glass offers you techniques to transform your brand.

The Practical Nature of Glass
For all its beauty, fragility and artistic history, glass has always enjoyed an eminently practical status as well. Glass is a nearly inert material, which is to say that it has no chemical interaction with most materials that it might come into contact with (except, of course, for acids strong enough to etch it, like hydrofluoric acid). Glass can be safely sealed to prevent oxidation, evaporation of liquid or intrusion by any air-borne contaminants. It is thus ideally suited as a long-term storage container. And clear glass admirably displays its contents with brilliant clarity.

It was not until the 17th century that glass making technology advanced to the point that more or less uniformly-sized neck bottles could be consistently produced, thereby permitting the marriage of bottle to cork stopper. The development of these two elements are credited as the two necessary prerequisites of the modern international wine trade.

During the 18th century, bottle shapes evolved more nearly into those we recognise today as being distinctively wine bottles. Made from black glass, they became taller and more cylindrical and most assumed the form of today’s Burgundy bottle. The first machine to make wine bottles was put into use in Cognac in 1894 and the age of truly uniform bottle shapes and sizes had begun.

When did the wine industry start using glass bottles, and how did they settle on their current size of 750ml? For the answer to these questions, you have to go back in time — back thousands of years to when wine was first cultivated and enjoyed.

The Romans, amongst other things, developed glass blowing. Glass was quickly found to be a good medium for storing wine – it did not affect the wine’s flavour, you could easily see what wine was inside the bottle, and so on. The trouble was with the method of manufacture. Glass at the time was hand blown, and bottles, therefore, varied widely in size. Consumers never knew exactly how much wine they were getting.

Time went on and coloured glass and various sizes and shapes were experimented with. Bottles were originally onion shaped, as this was easy to blow, but it was found that a longer, flatter shape was better for storing wine on its side, which helped it age properly and keep the cork wet. Bottles ended up being around 700ml to 800ml as an easy to carry size that was also able to be made easily.

In the 1800s, the industry found ways of making standard sized bottles, and regions began to settle on what they found was the ideal bottle size for their wines. Some chose 700ml, others 750ml, and so on. The maximum “standard” bottle size was around 800ml, although magnums and other special sizes did exist. In 1979, the US set a requirement that all bottles be exactly 750ml as part of the push to become metric.

Innovative Labelling and Decoration
Glass is also compatible with innovative labelling technologies. Pressure-sensitive, heat-transfer, and applied ceramic labelling all provide a no-label look while roll-fed paper, polystyrene labels and shrink films—long employed in the pharmaceutical industry as a security device—provide 360° graphic coverage. Pressure-sensitive labelling usually consists of inks printed on clear film, allowing consumers to see the product through the label. Most plastic containers are unable to take advantage of these modern labelling techniques.

Glass packaging has been used with new product categories such as new age beverages and drinks enhanced with nutraceuticals. Consumers still see resplendent glass packages showcasing the finest perfumes, the most distinguished wines and the smoothest microbrewed beers. And drug makers should take note that glass remains the package of choice for many medicines and pharmaceuticals.

When glass is made, it is heated to around 1600 degrees celsius, thus killing off any bacteria. Also, organic chemicals that might be present in the recycled glass are burned. This is why glass is used to pack products of premium quality – because no contamination from the packaging occurs. Glass is elegant, and glass packaged products stand out. With many unique shapes, glass containers give your product identity and character. And glass is fully recyclable: a glass bottle can be remade into a new, clean glass bottle. This is why glass is a truly environmentally friendly material – now and in future.

Types of Glass
There are many different types of glass with different chemical and physical properties. Each can be made by a suitable adjustment to chemical compositions, but the main types of glass are:
– Commercial glass also known as Soda-lime glass
– Lead glass
– Borosilicate glass
– Glass fibre

The glass forming processes
Like treacle, glass is fluid at high temperatures and its fluidity decreases as the temperature is reduced. Unlike water, glass has no specific melting or freezing point but is gradually changed from a solid to a liquid as the temperature is increased. It is this property of ‘variable viscosity’, which is used in forming a mass of glass into articles of beauty or utility.
Nothing matches glass’ versatility in shape and decoration, and there are a diverse range of techniques that can be used. Plus, technology is adding new options at a phenomenal rate.

Decorative techniques
– Coatings – Versatility of colour and texture.
– Embossing – A raised effect produced while in the mould.
– Transfers – Transfers can be used to add detailed decoration.
– Screen Printing – A technique which works well for bold designs.
– Pressure sensitive labelling – Delivery of quality precision labelling.
– Sleeving – Sleeving allows containers to feature all-over graphics.
– Satin etching – This technique allows for intricate designs and special effects.
– Sustainable design – An issue of paramount importance.
– 3D Computer aided design and manufacturing –  A revolution within the glass manufacturing industry.

Today’s precision processing gives us a dazzling array of strong, practical and attractive glass products. And manufacturers continue to invest millions across the supply chain to improve design, quality and lead times.

Limitations of glass
The current issues that glass manufacturers face across energy management and quality control are:

–  Lightweighting: The higher freight cost implications of “heavier” glass packaging constantly places demands on users to cut down packaging weight without compromising on mechanical strength or manufacturing viability.

–   Mould-making initial cost: Higher initial tooling-up costs for developing a new pack in glass versus the same in,say, extruded blow-moulded HDPE are a constant deterrent to would-be glass users. This, combined with high minimum order quantities entailed by the glass manufacturing process, places the choice of new glass packs in a severely disadvantaged position.

–   Quality control issues:  The high volume production entailed by the continuous output glass pack manufacturing lines demands a strict vigil on the quality of the production such that appearance and function are not compromised on.

The future of glass
Glass as a packaging material in its own right will always continue to exist. Many new applications and manufacturing processes may involve glass in combination with other materials. Research targetted at stabilising the microporous crystalline, “zeolite cage” structure of glass aims at creating “perfect glass.”  This could result in a mechanically and chemically stronger glass than the glass that is commonly used today. Premium cosmetic products and fragrances, where high-quality presentation and durability is of the utmost importance, could benefit a great deal from such a development. Would this mean that, if dropped, sophisticated fragrance bottles would no longer break? The current research could certainly lead to that obvious benefit in addition to more unexpected results such as the creation of glass polymer composites that offer “the best of both worlds.” In fact, US Company  Eastman Chemicals have recently launched a glass polymer grade for the premium cosmetics and fragrance market which is cheaper to produce, stronger and offers a finish that can match the quality of glass. The company claims that its Eastar Copolyester EB062 offers the capability of being blow-moulded into a wide range of shapes using a thick wall that resembles glass and does not compromise on quality.

The development of such glass alternatives would no doubt prove to be another threat to glass packaging manufacturers. Glass has traditionally had to stand up to tough competition from a wide variety of versatile resins in rigid or flexible form, which have been biting into its established markets.

The need to search for the “perfect glass” pack is urgent. It must offer the opportunity to combine the timelessness of ancient glass with the results of modern technology to create packaging forms of universal beauty and unexpected utility.

As you join us today from India and elsewhere, we have a favour to ask. Through these times of ambiguity and challenge, the packaging industry in India and in most parts of the world has been fortunate. We are now read in more than 90 countries as our coverage widens and increases in impact. Our traffic as per analytics more than doubled in 2020 and many readers chose to support us financially even when advertising fell to pieces.

As we come out of the pandemic in the next few months, we hope to again expand our geography and evolve our high-impact reporting and authoritative and technical information, with some of the best correspondents in the industry. If there were ever a time to support us, it is now. You can power Packaging South Asia’s balanced industry journalism and help to sustain us by subscribing.

Subscribe Now