Polycarbonate food-contact applications

Brussels, APME, 2003, pp.3, 29 cm, 3/3/05 POLYCARBONATE FOOD CONTACT APPLICATIONS ARE SAFE... 

For applications where polycarbonate homopolymers or copolymers lack sufficient thermal performance, blends with polyetherimide (PEI) are often used. PEI, which also contributes excellent flammability and low smoke generation to the alloy, may be combined with either straight polycarbonate or polycarbonate blends, depending on what other properties are required. The most common uses are found in light reflectors for automotive headlamps, components for aircraft interiors (especially wall and ceiling panels), and food-contact applications for microwave-to-table cookware. 

Recent developments include systems with better colour fidelity and handling properties. Dover s Doverphos HiPure 4 and 4-HR are high-purity tris-nonylphenyl phosphite (TNPP) processing and heat stabilizers, claimed to reduce overall costs. With 0.1% residual nonyl phenol, they are FDA-approved for food-contact applications and also used in medicals, colour-critical polyolefins, and styrenic block copolymers. They are effective also in acrylics, elastomers, nylon, polycarbonate, polyurethanes, polystyrene. PVC. ABS, and PET. 

To improve the resistance of household appliances to hiunid conditions, GE Plastics extended its range of polycarbonates diat are approved for food contact applications to include Lexan H . Even when subjected to heat and moisture over longer periods of time, this material retains its optical and mechanical properties, making it particularly suitable for applications such as steamer inserts for vegetables and heat-resistant containers. 

Polycarbonates are used in optics, transparent technical parts, aesthetic applications and protection devices for their transparency, mechanical properties, impact resistance, rigidity, good creep behaviour, fatigue resistance, insulating properties, dimensional stability, low moisture uptake, broad range of service temperatures (-100°C up to -i-135°C),food contact and sterilization possibilities for suitable grades. 

Hydrolytic stability in applications such as food-contact packaging and medical devices is afforded by Doverphos S9228, which is claimed to offer better colour and stability than 2,4-di-t-butyIphenyl phosphite, and also to function as an effective secondary anti-oxidant in combination with hindered phenols. Based on its pentaerythritol diphosphite technology, it can be used as a stabilizer for non-olefinic polymers, including PET, PBT, polycarbonate, and nylons. 

Two molecules of phenol are used for each mole of acetone. Because phenol and acetone are produced in a 1 1 molar ratio and consumed in a 2 1 molar ratio, there is an excess of acetone. Therefore acetone is often a glut on the market and is a generally inexpensive solvent. The BPA is used to make various polymers, including polycarbonate, many epoxy resins, and some phenolic resins. BPA is used in many polymers that have food contact and BPA can be present in minute amounts. Examples of these applications include some plastic containers, bottles, and can Unings. Therefore, there is some concern about possible health effects. It continues to be a matter of study, but one review of the research suggests that current exposure levels are safe [14]. Phenol is also used to make phenol resins and as a feedstock in the manufacture of caprolactam, the monomer for nylon 6. 

Addition levels vary between 0.05 and 1 phr, the higher concentrations being required in thin films, and lower dosages being adequate in certain polymers such as acrylics or polycarbonates which are inherently less sensitive to the effects of UV radiation. Non-toxic benzotriazole grades exist, which are suitable for use in applications involving food contact. 

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