Bayblend® FR4000 series - a new generation of flame-retardant polycarbonate blends

Flame-retardant blends made from polycarbonate and ABS are fire-resistant and lightweight and can withstand high mechanical loads. Thanks to these properties they have become firmly established as construction materials for thin-walled components in the electrical and electronics industries. Used for housings, they ensure that laptops, for example, are light and robust, function reliably and maintain their appearance over time. Bayer MaterialScience has once again considerably expanded the application and performance potential of these blends with the new product generation Bayblend® FR4000. It is based on an innovative flame retardance package using environmentally friendly technology.

"This material targets applications where high thermal stability and resistance to weathering are important," says Mathieu Jung, a materials expert at Bayer MaterialScience. "In terms of fire resistance, these products are superior to conventional polycarbonate/ABS blends and in many cases provide a particularly environmentally friendly alternative."

Very good hydrolysis, chemical and UV resistance
The products in this new series show excellent resistance to hydrolytic degradation along with exceptionally good resistance to chemicals such as fatty acids and hydrocarbons. The material also possesses outstanding UV stability. "This opens up new applications for our blends in components which are exposed to wind and weather. It represents a first for this class of materials," Jung says. The researchers at Bayer MaterialScience also succeeded in greatly improving the notched impact strength.

The outstanding fire resistance of the new product series is apparent from tests to determine their glow wire flammability according to IEC 60695-2-12 (Glow Wire Flammability Index, GWFI). This test examines how quickly a material sample set alight using a glow wire tends to self-extinguish. Grades of the Bayblend® FR4000 material meet the requirements at the maximum glow wire temperature of 960°C and burn only briefly. The results of tests according to the strict U.S. Underwriters Laboratories UL 94 V standard provide further evidence of its high flame retardance. In this case, the blends achieved the top V-0 classification at a specimen thickness of 1.5 millimeters.

Customized properties
The properties of the product types of the new series are optimized for specific applications. For example, one variant of the material has been designed with good chemical resistance and low-temperature impact strength in mind, making it well-suited for encapsulating lithium-ion batteries in electric vehicles. A fiber-reinforced blend with very high stiffness and strength (elasticity modulus ≥ 4.2 GPa) is also available for use in large structural components that have low wall thicknesses in some places.

Also new is a material with particularly good heat resistance (ball pressure test ≥125°C, IEC 60695-10-2) for applications that require this. "We are planning to expand the new product series in line with customer and market requirements, which will mean adding more variants with customized properties to suit specific applications," says Jung.

Source: Bayer MaterialScience