Glass as a material
Glass is an amorphous solid material and possesses an unordered glass-like molecular structure, which allows it to be solid at room temperature. The amorphous structure of glass is responsible for its transparent appearance and enables its special optical and mechanical properties. For production, natural or nature-identical inorganic substances are melted at temperatures from 1,400 °C to 1,650 °C. Among these raw materials are, among others, quartz sand, soda ash, lime, feldspar and potash. The exact composition of the starting materials later determines the respective properties of the resulting glass. Glass is moldable at temperatures around 1,000 °C and retains its shape even after cooling. In its basic form, glass is transparent. However, it can be arbitrarily tinted and dyed.
Glass - Questions & Answers
Glass as a packaging material offers several advantages. One of its most outstanding benefits is its extreme chemical stability. It does not interact with its contents. With the exception of hydrofluoric acid, almost all substances can be packaged in it. At the same time, it does not release any substances into its contents and is therefore physiologically harmless. Furthermore, there is no risk of the contents being contaminated by secreted substances. The relative invulnerability and density of this material is one of the greatest advantages of glass. It retains volatile substances. Odors, aromas, or solvents that keep the product liquid cannot diffuse through glass. They do not escape, but remain intact.
Since glass can be printed on directly, no additional films or paper sleeves are required to print the necessary or required information on the packaging.
In addition, packaging glass is 100% recyclable. The only problems with glass, compared to plastic or tinplate, are its higher weight and greater risk of breakage.
Glass is highly resistant to all types of organic and inorganic substances. Even problematic products such as oils and fats, alcohols, fuels, and other solvents, as well as strong acids and alkalis, can be packaged in glass without any issues. Unlike plastics, the use of glass as a packaging material is therefore not limited by the contents.
Glass as a material in the packaging industry offers so many possibilities that it will remain an integral part of packaging materials for a long time to come. Harmless, chemically extremely stable, and versatile in terms of shape and modification, it is and will remain attractive to many manufacturing industries.
Glass is an interesting packaging material for many industries. In the food industry, for example, it is indispensable in the form of beverage bottles. In the pharmaceutical industry, for example, it is used in the form of break-off ampoules and many injection vials, which would not be possible without glass. In the cosmetics industry, it is used in the form of ampoules or jars, among other things. The chemical industry, with its diverse product range, also likes to use glass as a packaging material due to its chemical stability.
Glass is mainly used to package liquids and powdered products. However, semi-solid products such as thickened sauces, creams, or gels can also be packaged in glass.
A comprehensive collection system for container glass was established back in 1974. In most cases, drop-off container systems are used for the separate collection of white, brown, and green glass. Over 250,000 such glass recycling containers are in use throughout Germany.
Separation by color is important in order to produce new glass packaging in the respective color from the shards. Glass packaging made of opal glass (milky white glass) should be disposed of in the white glass container.
Blue bottles and containers in other colors that cannot be clearly classified as white, brown, or green glass should be placed in the green glass container. This is because green glass is most tolerant of different colors without the color being affected.
Drinking glasses and window glass should not be placed in the glass recycling container as they have a different glass composition.
Energy-saving light bulbs and all types of light bulbs are considered residual or even hazardous waste and must not be thrown into the glass recycling container, but rather disposed of in the residual waste or at the recycling center (source: Federal Environment Agency). The better you sort your waste, the higher the recycling rate can be.
The green conscience is happy about glass as a packaging material because it is 100% recyclable—i.e., container glass can be 100% recycled as raw material (DIN EN 13430). Reusable packaging (DIN EN 13429) made of glass is also possible. Today, the majority of glass packaging therefore consists at least partly of recycled glass.
Depending on the color, up to 60% (green up to 90%) of recycled glass can be used in each new container. The material does not absorb anything (see also point 1 Advantages of glass as a packaging material) and the smooth surface allows the containers to be cleaned easily. Energy recovery or composting are not possible.