Acrylic (PMMA) sheets

Transparent plastics

It is not even a century ago that transparent plastics were first created. In 1928, the chemist Otto Röhm, born in Öhringen near Heilbronn in 1876 and died in Berlin in 1939, developed the transparent plastic that later came onto the market as Plexiglas and went down in history.

Important: transparent plastic is not the same as transparent plastic. There are now various types. The spectrum ranges from acrylic glass and polycarbonate through polyester and polyvinyl chloride to polyethylene and polypropylene. This guide deals with the specific properties of the variants just mentioned. The compact explanations help you to find transparent plastics in Heilbronn that are optimally suited to your individual needs, so that you can implement your projects excellently.

What are transparent plastics and how are they produced?

To produce transparent plastics in Heilbronn, the formation of macromolecules is required in every case.

A distinction is made between three variants:

• Polymerisation
• Polyaddition
• Polycondensation

a) Polymerisation Here, unsaturated monomers react in a chain reaction to form thermoplastic plastics. This chain reaction is triggered by certain initiators, for example ions or radicals.

b) Polyaddition Here, monomers react to form a long-chain polymer – under heat and pressure and in the presence of a catalyst.

c) Polycondensation Here, in addition to a macromolecule, another substance is formed by elimination. Water, for example, is possible. The individual chains are better linked to one another. This generally makes polycondensates harder and stiffer.

Note:

Thermoplastics can be produced by polymerisation, polyaddition or polycondensation, whereas thermosets can only be produced by polyaddition and polycondensation. Unlike thermosets, thermoplastics soften when exposed to heat. They are generally easier to process. Advantages and disadvantages of transparent plastics compared with glass One of the greatest advantages of transparent plastics compared with glass is their significantly lower weight. Transparent plastics from Heilbronn weigh only half of what real glass weighs. Furthermore, transparent plastics can be processed much more easily. Specific material properties can be adjusted in a targeted way to adapt them to the respective intended use. One of the disadvantages of transparent plastics compared with real glass is the poorly pronounced modulus of elasticity. In addition, there is the lower surface hardness on the one hand and the massive drop in strength at high temperatures from around 70 degrees Celsius on the other. Poorer fire behaviour is also among the disadvantages. Furthermore, it should be noted that the strength of transparent plastics is strongly time-dependent and that most versions become brittle through ageing. Note: Transparent plastics and glass are not opponents. Strictly speaking, combining the two materials has opened up special possibilities. For example, this led to the development of so-called laminated safety glass (VSG for short). It consists of at least two real glass panes which, through the integration of a high-polymer film, are so stable that if the panes break, the glass pieces remain adhered to the film.

Transparent plastics in Heilbronn – these types are available

In construction, acrylic glass (PMMA) and polycarbonate (PC) are primarily used as load-bearing building materials. In addition, the following materials are mainly used as transparent plastics in Heilbronn:

• Polyester (A-PET, PET-G)
• Polyvinyl chloride (PVC)
• Polyethylene (PE)
• Polypropylene (PP)

The characteristics and most important applications of all these transparent plastics are now presented in more detail.

Properties of acrylic glass (PMMA)

Acrylic glass is a colour-neutral and highly transparent plastic. It is often used as an alternative to glass. This is mainly because acrylic glass is more impact-resistant on the one hand and lighter than real glass on the other. The considerable advantages of this transparent plastic also include the fact that it can be thermoformed and bonded perfectly. The edges can be polished to a highly transparent finish. Not to forget that acrylic glass is weather-resistant and permanently UV-resistant. Disadvantages of this practical, versatile material are its susceptibility to scratching and the lack of fire protection classification according to DIN 4102-1 B1. Speaking of versatile: acrylic glass is suitable for various applications.

Here is an overview:

• Practice signs
• Brochure stands
• Picture glazing
• Illuminated advertising
• Medical technology
• Furniture construction
• etc.

A distinction must be made between cast and extruded acrylic glass:

a) Cast acrylic glass (GS) An acrylic glass sheet is cast as a liquid mass between two sealed glass panes. After heating, the sheet cools to the intended thickness. The fact that greater thickness tolerances arise during curing is due to the absence of pressure. The manufacturing process results in transparent plastics with higher surface brilliance.

manufacturing process results in transparent plastics with higher surface brilliance.

b) Extruded acrylic glass (XT) Extruded acrylic glass is the result of so-called extrusion. The term is derived from the Latin verb 'extrudere' (to push out, to drive out). In this special method, curable masses (viscous to solid) are first pressed out of a shaping opening and then rolled to the desired thickness. The result is a sheet with a particularly even surface (tight thickness tolerances).

Note: The prices for acrylic glass GS are generally higher than those for acrylic glass XT. The reason for this is the significantly greater effort involved in production. Both are suitable for printing. Acrylic glass GS delivers better depth brilliance, while acrylic glass XT delivers better contour sharpness.

Important note on the use of sheets made of acrylic glass: After longer storage, the transparent plastics should be pre-dried. This reliably prevents the formation of bubbles through the release of moisture.

Quick overview of the advantages and disadvantages:

• highest transparency at all thicknesses
• no colour distortion
• extremely weather-resistant
• little fire protection

Tip: If fire protection regulations play a role, it is better to use other transparent plastics. PC and PET, for example, are options. Both fulfil the DIN standards 4102-1/EN 13501 (depending on material thickness).

Properties of polycarbonate (PC)

Polycarbonate acts as a shatter-proof and enormously impact-resistant alternative to acrylic and real glass. This is why the transparent plastic is optimally suited as splinter protection in areas at massive risk of vandalism. In addition to being unbreakable, PC has three other significant advantages: the material can be thermoformed and can be cold-bent up to six millimetres. It also fulfils the criteria of fire protection classification according to DIN 4102-1 B1: polycarbonate is flame-retardant at two to six millimetres.

Caution: The softer surface makes polycarbonate even more susceptible to scratching than PMMA.

Potential areas of application for PP:

• Motorcycle helmet visors
• Safety goggles
• Machine guards
• Display cases
• Display cabinets
• Illuminated advertising
• CD blanks
• Burglary protection
• Roofing
• Protective glazing (e.g. ice rink)
• etc.

Polycarbonate is produced using the extrusion process (for explanation see acrylic glass XT). To ensure long-lasting UV protection (up to ten years), a so-called UV longlife coating is required.

Note on use: Like acrylic glass, polycarbonate must also first be pre-dried after longer storage. Otherwise, bubbles can form through the release of moisture during thermoforming of the material. PC sheets can be printed excellently. Incidentally, polycarbonate is more expensive than acrylic glass.

Quick overview of the advantages and disadvantages:

• shatter-proof
• impact-resistant
• flame-retardant
• very susceptible to scratching

Tip: If the material is to be reasonably scratch-resistant, it is advisable to use PMMA instead of PC. Acrylic glass has the somewhat more resistant surface when it comes to scratches. And: during lamination, polycarbonate can still outgas and cause bubble formation. To rule this out from the outset, PET-G is better suited. The latter material does not absorb moisture and therefore does not outgas.

Properties of polyester (A-PET, PET-G)

Polyester is an amorphous plastic. In physics and chemistry, the term "amorphous" refers to a substance whose molecules do not form ordered structures but exhibit an irregular pattern. Polyester is ideal for cold-bent and flat applications. Due to the amorphous molecular structure, polyester crystallises when heated. It turns white and becomes rigid and accordingly inflexible. To eliminate this property, the addition of glycol (dihydric alcohol) helps. As a result, polyester can be thermoformed very well.

Note: Conventional, amorphous polyesters have the abbreviation A-PET, those with glycol the short form PET-G. The FDA and BDA approve A-PET and PET-G for direct contact with food and medical applications. Furthermore, the transparent plastics are flame-retardant (fire protection classification EN 13501-1). Outdoors, PET-G is weather-resistant for up to three years – A-PET for up to four years. UV-stabilised versions of polyester are possible. Both variants offer extremely good printing results.

A-PET and PET-G are best suited for the following applications:

• Protective glazing
• Shopfitting (e.g. freezers)
• Vending machines (e.g. drinks)
• Trade fair construction
• Illuminated advertising
• Displays
• etc.

Tip: PET-G has a decisive advantage over PMMA and PC. With this material, no pre-drying is necessary before thermoforming. Polyester does not absorb moisture. A-PET also clearly impresses with a specific characteristic – its very high resistance to mineral oils as well as cleaning agents and solvents.

Quick overview of the advantages and disadvantages:

• food-safe
• flame-retardant
• thermoformable without pre-drying
• moderately weather-resistant

Tip: If longer-term outdoor use is desired, we recommend choosing an alternative to PET-G and A-PET. Suitable options include PC-UV (longlife) for up to ten years of UV protection and PMMA for lasting (20 to 30 years) UV stability.

Properties of polyvinyl chloride (PVC)

Polyvinyl chloride (PVC for short) is a thermoplastic polymer. This transparent plastic is one of the most frequently processed versions. In principle, a distinction is made between rigid and flexible PVC. If a softer and more flexible plastic is required, plasticisers are used in the production of the PVC material. Their proportion can be up to 40 percent. If, on the other hand, a particularly robust and stable plastic is required, rigid PVC is the right choice. It contains no plasticisers. PVC is a thermoplastic – which is why the plastic becomes soft and malleable when heated.

Possible areas of application for flexible PVC:

• self-adhesive vinyl films
• digitally printable banners

Possible areas of application for rigid PVC:

• Displays
• Large slides
• Light boxes
• Packaging (including for food)
• Awards (in retail)
• Registers and scales
• Trade fair construction

Notes on rigid PVC:

1. Rigid PVC complies with EU Regulation 10/2011, Annexes 16 and 22. This means it may come into contact with food. Furthermore, this transparent plastic fulfils all the criteria of EU Directive 94/62/EC, which relates to packaging and packaging waste.

2. Anyone using rigid PVC is dealing with an odourless and tasteless material. The plastic is also water-resistant.

3. The easy-to-process material can be printed with various printing processes: screen and flexo, gravure as well as UV offset and UV digital printing are all possible. Before extensive printing, it is advisable to first test the preferred process on an unneeded offcut of rigid PVC to ensure compatibility.

Attention: The transparent plastics cannot be printed with latex or ecosolvent inks.

4. Rigid PVC is ideally suited for further processing such as cutting, bending, edge trimming, thermoforming and/or bonding.

5. To reduce the susceptibility of the plastic to scratching, one-sided embossing is advisable. It produces an anti-glare effect.

Quick overview of the advantages and disadvantages (rigid PVC):

• food-safe
• odour-/tasteless
• water-resistant
• moderately heat-resistant

Tip: Rigid PVC should be protected from great heat exposure (more than 60 degrees Celsius).

Properties of polyethylene (PE)

Transparent plastics made of polyethylene (PE for short) are characterised in particular by their high chemical resistance. They are also electrically insulating and have good sliding properties. Polyethylene is enormously stretchable and impact-resistant. Compared with other transparent plastics, the poorer mechanical characteristics have a disadvantageous effect. This means polyethylene is less strong and hard. The material also performs worse in terms of stiffness than other transparent plastics in Heilbronn.

Note: PE-LD (LD = low density) has the greatest transparency, followed by PE-LLD (LLD = linear low density). PE-HD (HD = high density) comes with the lowest transparency.

Typical areas of application for polyethylene:

• Film production in general
• Sealing medium in composite films
• Cable sheathing
• Industrial packaging
• etc.

Quick overview of the advantages and disadvantages:

• high stretchability
• good impact resistance
• low sliding friction
• lower strength

Properties of polypropylene (PP)

With a share of around 20 percent of total production, polypropylene (PP for short) is one of the most important plastics of all. Chemically, the material is similar to polyethylene (PE). However, it is significantly harder and stronger as well as able to withstand higher thermal loads. The maximum continuous service temperature is around 100 degrees Celsius. It should also be noted, however, that below zero degrees Celsius the impact sensitivity of PP increases more than that of PE.

Tip: The polymerisation conditions can be selected in such a way that, in addition to isotactic and syndiotactic polymers, even atactic polymers can be achieved. This fact enables a great variety of potential types.

Note: Syndiotactic polypropylene (PP-S) is transparent and extremely impact-resistant.

PP can be used for the following applications:

• Packaging films
• Rigid packaging
• Cheque and business cards
• Housings (small electrical appliances)
• Moulded parts (household appliances)
• Displays
• Ceiling hangers
• etc.

Quick overview of the advantages and disadvantages:

• hard and strong
• extremely impact-resistant
• able to withstand thermal loads
• becomes brittle below 0 °C

Find and order transparent plastics in Heilbronn

Acrylic glass (PMMA), polycarbonate (PC), polyester (PS), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP): these and many other transparent plastics are available in Heilbronn from your specialist partner. Take a look at the large range and contact us if you have questions about the materials or would like to order transparent plastics. We will be happy to advise you individually and support you in realising your projects to your complete satisfaction. BW-Kunststoffe is your competent contact when it comes to transparent plastics in Heilbronn.