Terlux® (MABS) is primarily processed through injection molding, but any process suitable for thermoplastic molding compositions may also be used.

Predrying

Terlux pellets can absorb small amounts of moisture under adverse conditions of storage or transport. This can cause surface defects to arise during processing, taking the form of streaks, lines or bubbles. We therefore recommend that Terlux is pre-dried for about 2 hours at about 70°C before processing.

Compatibility with other thermoplastics

Terlux should not be mixed with other thermoplastics; even small amounts of other plastics, including transparent ones, cause irreversible clouding.

Reprocessing

Terlux may be reused as regrind if it has been processed as specified and has not been contaminated or thermally degraded. Since regrind has a larger surface area than pellets and therefore absorbs moisture more rapidly, it must be dried before being reused. Virgin pellets should always be used for parts which are subject to high quality requirements.

Terlux MABS can be processed on any commercially available injection molding machine.

Injection unit

Universal screws are highly suitable. Guide values for proven screw designs are as follows:

Total length: 18-22 D (compression ratio 2-2.5)  Feed section: 0.5 L  Compression section: 0.3 L  Metering section: 0.2 L

 where D=screw diameter; L=total length.

Gate and mold design

It is generally possible to use any of the usual types of gating. Molds with hot-runner systems can also be used. Design guidelines for mold construction are given in VDE 2006.

Mold temperature control

Shrinkage and, to some extent, the thermal and mechanical properties of the part can be influenced via the mold temperature. Higher mold temperatures provide better weld line strength and lower internal stresses, and therefore also reduce warpage. Mold temperatures which have proven successful in practice are between 50 and 75°C.

Processing temperature

Melt temperatures of 230-260°C give optimum transparency. Excessively high melt temperatures and long residence times may cause slight yellowing.  The highest part transparency is achieved when the mold surface is highly polished.

Flow behaviour

Fig. 6 shows the flow behavior of Terlux 2802 TR and 2812 TR as a function of melt temperature and injection pressure using the spiral flow test. This test commonly approximates closely to practical experience with similar resins.

Mold release

Injection moldings made from Terlux exhibit good mold release properties. Drafts of 0.5 to 1° are generally sufficient. For textured surfaces, the draft depends on the depth of the texture and should be greater than the values given.

Shrinkage

The shrinkage of the part typically ranges from 0.4 to 0.7%. Post-shrinkage is negligible. Shrinkage not only depends on the type of material used, but also on the design of the part and the processing conditions.

Safety precautions during processing

No adverse health effects on processing personnel have been observed where processing of the products is carried out correctly and suitable ventilation is provided in production areas. Maximum allowable concentrations (MAC) must not be exceeded, and in Germany are 20 ml/m³ for styrene, 50 ml/m³ for methyl-methacrylate and 5 ml/m³ for methyl acrylate. Guideline levels in Germany for acrylonitrile and 1,3-butadiene are 3 ml/m³ and 5 ml/m³, respectively. Acrylonitrile and 1,3-butadiene are category C 2 carcinogenic substances for which carcinogenic activity is assumed as a result of tests carried out on animals.  Experience has shown that when Terlux is processed correctly with appropriate ventilation the levels are far below the limits mentioned above. Further information is given in our Terlux 2802 TR and Terlux 2812 TR safety data sheets.

Disposal

Under German regulations MABS is classified as polystyrene waste. Solid plastic wastes of this type are exempt from the monitoring which applies to other types of waste, and normally it can be landfilled (cf. Terlux safety data sheets). Terlux wastes are inert in landfills. In Germany Terlux is classified as water hazard class 0.  Subject to official regulations, Terlux may also be incinerated in a suitable incinerator, e.g. a domestic waste incinerator. The calorific value of Terlux is about 10 kWh/kg, about 70% higher than that of wood. Complete combustion yields carbon dioxide, water and nitrogen, which oxidizes to a limited extent to yield nitrogen oxides.

Recovery

Wastes, whether melt or used parts, consisting solely of Terlux can be recovered, i.e. can be fed back to the process as regrind (cf. Reprocessing, above). Depending on the age and wear of the used parts to be recycled, certain properties may have changed. It is therefore important to check whether the recycled material is suitable for the intended application.