LEXAN™ – What Is It? Properties, Applications and Polycarbonate Grade Selection

LEXAN™ is a family of polycarbonate (PC) based materials developed for demanding technical applications. LEXAN™ polycarbonates are known for high impact resistance, the availability of transparent grades and good thermal behaviour. Individual grades differ, however, in flow, UV stabilisation, flammability class, additives, reinforcement and intended use.

For that reason, the properties of a specific material must always be confirmed in the current technical data sheet of that grade.

What is LEXAN™?

LEXAN™ is a trade name for a family of polycarbonate-based materials. PC stands for polycarbonate — the polymer type — and it belongs to the engineering thermoplastics used for load-bearing and functionally critical parts.

Danje-Polymer supplies LEXAN™ primarily as engineering thermoplastic granules for further processing, mainly injection moulding and extrusion.

Do not equate every LEXAN™ resin with the finished polycarbonate sheet products used in construction and glazing. These are separate product groups with different purposes.

Is LEXAN™ the same as polycarbonate?

Not exactly. Polycarbonate (PC) is the name of a polymer type, while LEXAN™ is the trade name of a specific family of polycarbonate-based materials.

LEXAN™ is polycarbonate, but not every polycarbonate is a LEXAN™ material.

What properties does LEXAN™ have?

Properties depend on the specific grade. The characteristics below describe the typical behaviour of the LEXAN™ polycarbonate family and the specialised solutions available in the portfolio.

Impact resistance

Impact resistance is one of the characteristic reasons polycarbonate is selected for demanding applications such as guards, housings and parts exposed to impact loads. Actual impact values differ between grades and are reported in the data sheets, for example as Charpy and Izod results.

Transparency and optical properties

Transparent grades are available and are used for lenses, light guides, transparent covers and lighting components.

Not every LEXAN™ grade is transparent.

Coloured, glass-reinforced and additive-modified grades are opaque, and light transmission and haze values should be checked in the grade data sheet.

Thermal properties

Polycarbonate is used where greater heat resistance is required than many commodity plastics can offer.

HDT, RTI and the permissible service temperature depend on the specific grade and on the conditions of use.

This is why no single universal continuous service temperature is quoted here for the whole LEXAN™ family.

UV stabilisation

Not every LEXAN™ grade is UV stabilised.

Selected grades include UV stabilisation — the LEXAN™ 123R data sheet describes the material as UV stabilized, as does the data sheet for LEXAN™ 203R. For outdoor applications, UV stabilisation and expected durability under the relevant exposure conditions must be verified for the specific grade.

Flame-retardant grades

The portfolio contains both standard grades and dedicated LEXAN™ FR flame-retardant grades. UL 94 classification depends on the grade and on specimen thickness — the same family name does not imply the same flammability class.

For that reason the LEXAN™ family as a whole should not be described as flame retardant. The required class must be confirmed for the selected grade, colour and wall thickness.

Where is LEXAN™ used?

Automotive

Potential application areas include lighting components, transparent components, interior and exterior parts, and sensor or optical covers, as far as the selected grade meets the design requirements.

Electrical and electronics

Housings, covers and electrical or electronic components. Some applications require selected flame-retardant grades, in which case the class is confirmed for the specific grade and thickness.

Lighting and optics

Lenses, light guides, LED covers and other transparent optical components, based on transparent grades.

Healthcare

The portfolio includes dedicated LEXAN™ Healthcare grades intended for selected medical and pharmaceutical applications. Such projects must be based on a specific grade and on the manufacturer's current regulatory documentation.

Food-contact applications

Compliance with food-contact requirements must be confirmed for the specific grade, colour, market and application on the basis of current documentation.

How do you select the right LEXAN™ grade?

A practical checklist before the material decision:

1. Processing technology (injection moulding, extrusion, other).
2. Part geometry, including wall thickness and flow length.
3. Required melt flow.
4. Transparency and colour.
5. Mechanical requirements, including impact and stiffness.
6. Service temperature conditions.
7. UV and weather exposure.
8. Required flammability class and the thickness it must apply to.
9. Regulatory requirements for the industry and market.
10. Dimensional stability of the part.
11. Glass fibre reinforcement or other additives.
12. Required documents and certificates.

Grade selection should be based on the current technical data sheet and the requirements of the specific application, not on the LEXAN™ family name alone.

LEXAN™ 123R – what makes this grade different?

LEXAN™ 123R is a polycarbonate described in the manufacturer's data sheet as an 18 MFR material with a melt volume rate (MVR) of 21 cm³/10 min at 300 °C / 1.2 kg (ISO 1133).

The data sheet for this grade also states:

• base polymer: polycarbonate (PC),
• UV stabilisation (UV stabilized),
• an internal mould release additive,
• a UL 746C f1 rating,
• a UL 94 HB flammability rating at the thicknesses stated in the data sheet.

The properties of LEXAN™ 123R are not the properties of the whole LEXAN™ family.

How do LEXAN™ grades differ?

The table below shows how much the material profile can change within a single family. All characteristics come from the manufacturer's data sheets for the individual grades.

UL 94 classifications apply at the specimen thicknesses stated in each grade's data sheet.

This overview is indicative. Current properties, classifications and regulatory data must always be checked in the current documentation of the specific grade.

LEXAN™ vs PMMA

LEXAN™ is a polycarbonate (PC) based family. PMMA is polymethyl methacrylate, also known as acrylic — a different polymer.

The comparison usually comes down to these selection factors:

• impact resistance — the typical argument for polycarbonate,
• surface scratch resistance,
• the optical requirements of the part,
• heat resistance under service conditions,
• weather and UV exposure,
• processing technology and material behaviour in the process,
• requirements for the finished part, including finishing and machining.

Neither material is universally "better" — the decision follows the requirements of the specific application, confirmed against data sheet values.

Where can you find a LEXAN™ technical data sheet?

A Technical Data Sheet must always be checked for the exact grade and region — it is the only reliable basis for design and material selection.

Parameters that vary from grade to grade include:

• MFR / MVR, i.e. melt flow,
• mechanical properties,
• thermal properties,
• UL rating, together with the specimen thickness,
• UV stabilisation,
• glass fibre content,
• regulatory status.

If you need the current technical data sheet for a specific LEXAN™ grade, contact Danje-Polymer.

An overview of the family and typical grades is also available on the product page: LEXAN™ polycarbonate (PC) at Danje-Polymer.

Frequently asked questions about LEXAN™