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DURAN Group celebrates 120 years of laboratory glassware made from borosilicate glass

The material that became an international success

Tobias A. Thiele, DURAN Group

Summary

The Glastechnische Laboratorium Schott & Genossen Jena (now SCHOTT AG) launched the first laboratory glassware made of borosilicate glass on the market in 1893. Until then, soda-lime glass and lead glass had been used and borosilicate glass represented a completely new third type of glass. Its main features are high resistance to heat and temperature changes, and very high chemical resistance and mechanical strength. With this invention and its subsequent further development, the chemist and glass technician, Otto Schott, became the founder of modern glass technology. The invention of laboratory glassware made of borosilicate glass made a number of new scientific methods of application possible. Today, borosilicate glass is still an essential material used in laboratories, industrial applications and households around the world. Alongside standard laboratory glassware, the material is also used to make thermometers, lamp chimneys, ampullae, syringes, baby bottles, chemical apparatus and coffee machine jugs. The DURAN® brand was registered in 1938. Today, the DURAN Group's laboratory glassware range includes over 5,000 standard articles. As a result of the fully automated production process, DURAN® laboratory glassware is characterised by extraordinarily consistent, technically reproducible quality. Even 120 years after it was introduced on the market, DURAN® is a unique and essential brand for important industries – and still holds potential for the innovations of tomorrow.

Dr Otto Schott (1851 – 1935), chemist and glass technician, inventor of borosilicate glass

History

With the development and market introduction of borosilicate glass 120 years ago, Otto Schott became the creator of a new, third type of glass. The soda-lime glass and lead glass that had been used until then have considerable weaknesses: they are not resistant to acids or alkaline solutions, or even water after permanent exposure. Furthermore, they are not resistant to high temperatures or quick changes in temperature. This makes them unsuitable for use in laboratories, for lamp chimneys and for precise temperature measurements.

 

An epoch-making invention

Otto Schott started from this basis and began developing glassware in 1887 using flint ("silicate") and boric acid ("boro") as a glass former until it reached scientific and technological maturity. From 1891 onwards, thermometer glass was made from borosilicate glass, the new type of technical glass. This made scientific measurements up to 500 degrees Celsius possible for the first time. A further milestone was reached in 1893: the Glastechnische Laboratorium Schott & Genossen Jena (what is now SCHOTT AG) launched the first laboratory glassware made of borosilicate glass on the market. It is characterised by three main features that are still essential for good laboratory glass today:

  • high resistance to heat and changes in temperature
  • very high chemical resistance
  • mechanical strength

The new company was founded by three men: the chemist and glass technician Otto Schott, the physics professor Ernst Abbe, and Carl Zeiss. The extensive market introduction of the new type of laboratory glass occurred in winter 1893/94: the first leaflet entitled "Jena appliance glass with high resistance to differences in temperature and chemical attacks", advertised flat-bottomed flasks, Erlenmeyer flasks and beakers in different sizes and announced the manufacture of other laboratory apparatus "on request". Otto Schott already knew that he would revolutionise the procedures and structures in laboratories all over the world with this product range. Analysis results could be reproduced thanks to the availability of standardised boiling containers, test tubes and storage vessels – representing an important advancement in scientific work. As early as 1897, the company published a catalogue-like price list with product sketches and precise dimensions. One major advantage offered by the new laboratory glass was its extraordinary resistance to chemical substances.

Market introduction: the first leaflet on laboratory glassware made from borosilicate glass was published by Schott in 1893

The response to the product made purely by hand was immense. The product range was then added to over time and within just a few years, the new laboratory glassware made of borosilicate glass had penetrated the market: by March 1901, the glass factory was supplying 35 companies in Germany and 49 in the rest of Europe, the US, Canada and South Africa. The application areas for borosilicate glass were expanded: it had been used exclusively as glass for thermometers since 1891, but just two years later it was also being used as laboratory glassware and lamp chimneys for glass lighting. This was followed by many other applications, for example as pharmaceutical packaging and domestic glassware.

Market introduction: the first leaflet on laboratory glassware made from borosilicate glass was published by Schott in 1893

To differentiate between the different products, a clear designation was needed for the laboratory glassware made of borosilicate glass – a brand with the corresponding brand characteristics that could be used internationally. A brand name was soon found: the material's high resistance to chemicals and temperatures resulted in the brand name DURAN® (durus = hard, durable). The brand was registered at the State Patent Office in Berlin in 1938.

Today, borosilicate glass is used in many different ways in industry and in the home. The material is used to make ampullae, syringes, baby bottles, chemical apparatus and tubing, fire protection glass, coffee machine jugs and glass kettles, for example.

 

Otto Schott – "the founder of modern-age glass technology"

With the development of borosilicate glass, the chemist and glass technician, Otto Schott, opened up new dimensions for glass technology and revolutionised modern chemistry. Without this invention, significant developments in biology, bacteriology, medicine, pharmaceutics and chemistry would not have been possible, or at least would not have become possible so quickly. The invention of laboratory glassware made of borosilicate glass made a number of methods of application possible that were previously unimaginable. In 1925, Otto Schott was honoured by the Deutsche Glastechnische Gesellschaft as the "founder of modern-age glass technology".

Registration of the DURAN® brand at the State Patent Office (1938)

The DURAN® brand

Since the turn of the century, borosilicate glassware produced by the Jena-based glass factory has been further developed and continuously improved to cover new application areas. Even today, the manufacture of borosilicate glassware remains one of the core competencies of the international technology group SCHOTT. DURAN® is the best known brand in SCHOTT’s borosilicate family. Today, the name DURAN® is used exclusively for borosilicate glass 3.3, a material that meets the criteria for resistance to water and acids, thermal expansion coefficient, density and conductivity as defined in the international DIN-ISO 3585 standard.

 

DURAN Group

Over the last 120 years, DURAN® glassware has proved its worth not only in laboratories, but also in industrial applications and households around the world. DURAN® tubing and rods for scientific and technical applications are manufactured at the SCHOTT site in Mitterteich (Germany). In 2005, the DURAN Group was bought out of SCHOTT AG by Munich-based investor ADCURAM and is one of the world's leading international manufacturers of borosilicate glass. The medium-sized company has two divisions (Laboratory Glass and Engineered Glass) and covers the entire value-added chain from glass melting to precise forming and processing procedures. At the sites in Mainz and Wertheim (Germany) and Pula (Croatia), a comprehensive range of over 5,000 standard articles are produced, in addition to a number of customer-specific special products for industrial applications in sectors such as mechanical engineering, the chemical industry and medical technology. Its customers include development departments from the chemical industry, companies from the biotechnology, beverage and food industries as well as quality assurance laboratories. In addition to the production and sale of laboratory glassware, the DURAN Group also handles logistics, which means that the products are transported quickly from the fully automated high-rack warehouse to their destinations across the globe.

 

Production

DURAN® stands for safe products of a consistently high quality that is guaranteed by a high level of investment in quality assurance and state-of-the-art manufacturing and testing procedures. To guarantee the safety of laboratory workers and the reproducibility of analysis results, the DURAN Group has committed itself to manufacturing according to strict standards for laboratory glassware. In addition to the properties of the material, these specifications relate primarily to safety-relevant criteria. This covers, in particular, characteristics such as stones, bubbles or streaks in the surface of the glass that, as a result of stresses, could lead to dangerous breakages if heated, potentially causing injury.

Fully automatic glass production: glass bulb on the blowing machine shortly before the mould is closed

Unlike most of its competitors, who manufacture their products by hand using glass tubes, DURAN Group produces laboratory glass using fully automatic processes and the very latest technology. The DURAN Group's melting tank runs around the clock to ensure consistent product quality. The precise size and shape of the glassware is achieved with the help of moulds. Firstly, this is of great importance for the resistance to mechanical impacts and to changes in temperature. Secondly, it facilitates precise reproducibility through comprehensive monitoring of the production process (melting, forming, cooling, quality control). DURAN® thereby guarantees both compliance with the dimensions and tolerances of the major quality standards such as ASTM, ISO and DIN, as well as a binding production numbers. The fully automated glassware production method thereby offers distinct advantages over manual production, which greatly depends on the skills of the glass worker and the quality of the tube material supplied by a third party. Furthermore, dimensions and tolerances as well as comparably high production volumes are difficult to achieve using manual production methods.

The original: today, the DURAN® GL 45 laboratory glass bottle is standard equipment in laboratories around the world

Quality – Made in Germany

In the lab, the DURAN® brand stands for the highest levels of safety and reliability thanks to the reproducibility of the analysis results (in this regard, the product meets stricter criteria than those stipulated by the various standards, as the permitted tolerances are not utilised in full in production) and availability. A further advantage over unbranded laboratory glassware made from borosilicate glass: the application of the DURAN® brand on each product certifies compliance with strict, self-imposed production specifications and can therefore be identified by the user in the event that issues arise relating to product liability. Many DURAN® products are retraceable as far as the production date (batch certificate).

 

Properties

The properties of DURAN® correspond to the specifications of ISO 3585. Compared to other borosilicate glass 3.3, DURAN® is characterised by extraordinarily consistent quality that can be technically reproduced. Very good chemical resistance, inert behaviour, a high usage temperature, minimal thermal expansion and the resulting high degree of resistance to changes in temperature are just some of its key properties. This optimum physical and chemical behaviour predestines DURAN® for use in laboratories as well as for large-scale systems in the construction of chemical apparatus. It is also considered to be a technical multi-purpose glass in all application areas requiring extreme thermal resistance, resistance to changes in temperature, mechanical strength and extraordinary chemical resistance.

 

Very high chemical resistance

DURAN® borosilicate glass 3.3 is highly resistant to water, neutral and acid solutions, strong alkaline solutions and their compositions, chlorine, bromine, iodine and organic substances. Even at longer exposure times and temperatures above 100°C, it exceeds the chemical resistance of most metals and other materials. Only hydrofluoric acid, concentrated phosphoric acid and strong alkaline solutions strip the glass surface (glass corrosion) when high temperatures (>100°C) also occur. Thanks to its high resistance to water, DURAN® complies with USP, EP and JP guidelines and is a neutral glass that corresponds to glass type 1. This means that DURAN® can be used in almost all pharmaceutical applications and in contact with foodstuffs.

Inert behaviour

Thanks to the almost inert behaviour of DURAN®, there is no interaction – e.g. ion exchange – between the medium and the glass. This rules out any influence on the experiments.

High usage temperature

The highest permissible usage temperature for short-term use of DURAN® glassware is +500°C. At temperatures of +525°C and above, the glass will begin to melt and, from temperatures of +860°C, it will change into a fluid state.

DURAN® can be cooled down to the maximum possible negative temperature and is therefore suitable for use in liquid nitrogen (approximately -196°C). Generally, use down to -70°C is recommended for DURAN® products. When thawing, it is important to make sure that the difference in temperature does not exceed 100 K. DURAN® glassware is also suitable for use in the microwave.

Minimal thermal expansion and high resistance to changes in temperature

DURAN® glassware is characterised by high resistance to changes in temperature (ΔT=100 K). With its very low coefficient of linear expansion, literally no tension is built up in the article, when the temperature changes rapidly. Therefore, it does not crack or shatter, when boiling water is filled in.

Optical properties

In the spectral range of approximately 310 to 2,200 nm, the absorption of DURAN® is negligible. It is transparent and colourless. Larger coating thicknesses (axial inspection for tubes) appear slightly yellow/greenish.

Even wall-thickness distribution

The strictly monitored, even wall thickness is the most important parameter for mechanical stability and resistance to changes in temperature. This results in a longer product service life and corresponding cost savings as well as in increased safety for the user.

Raw material

DURAN® guarantees raw materials of a consistently high quality by means of long-term suppliers, ultra-modern weighing facilities, fully automatic batch preparation and daily retain samples of the raw materials.

Moulding

DURAN® stands for decades of manufacturing expertise and experience, not only in moulding by hand, but also in fully automatic production lines. Technically mature cooling processes guarantee stress-relieved products.

Quality

The DURAN Group is certified in accordance with ISO 9001 and consistently manufactures in line with DIN/ISO specifications. Continuous process control takes place according to ISO 2859.

Traceability

Many DURAN® products are retraceable as far as the production date (Retrace Code).

 

Outlook

DURAN® is a unique material that has become essential for many important industries due to its excellent properties. It is also a material that holds great potential for the innovations of tomorrow. The DURAN Group works continuously on the development of additional properties in order to extend the range of technical application possibilities. These include intelligent coatings with temperature-resistant plastics such as DURAN® Protect, which increase the safety of glass containers by guaranteeing effective protection against leakage. Coatings on the interior based on silicon oxide are also of significance: they support Research and Development in optimising the quality of analysis results. In the future, it will be possible to significantly improve work processes in the laboratory and – above all – their documentation through the combination of active memory chips (RFID) with glassware articles.

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