Polybutylene terephthalate (PBT) is a resin that exhibits an excellent balance of properties including mechanical properties, electrical properties, durability, and moldability. Furthermore, it is compounded with various additives and used as an unfilled material, a reinforced material, and a flame-retardant material. DURANEX^® is a typical PBT answering to diverse needs in terms of usage applications, components and customers. Furthermore, we have prepared a grade line-up with a variety of attributes, and the material is widely used in various sectors. This includes the automotive sector, where advanced mechanical properties and high durability are required, and the electrical/electronics sector, where the demands with regards to flame resistance, electrical properties and the environment are severe.

In terms of recent trends, automotive, electrical, electronic, and OA products have advanced features. The various parts which comprise these products will be miniaturized. Therefore, high strength, high stiffness, and high flowability are required for the resin used in these parts. Our company has focused on high-flowability technologies in the injection molding process to develop the DURANEX SF Series, which exhibits approximately double the flowability of standard PBT.

The superior flowability of the DURANEX SF Series enables filling of super-thin wall sections of the molded parts, which had previously been difficult with standard PBT. We therefore believe that this material has the potential to widen the applicable scope of PBT. In addition, the series will contribute to rationalization studies of thin-walling and lightweighting in product design, and rationalization studies in relation to molding (expansion of molding parameter range, multi-cavity molding, molding cycle time reduction). We also anticipate that energy reductions may be achieved through this rationalization.

The DURANEX SF Series consists of a standard GF-reinforced type (SF3300), a low warpage type (SF733LD), and a high filler type (SF755).

Figure 2 compares the thin-wall flowability of SF Series resin (SF3300) with other resins. The thin-wall flowability of SF3300 lies midway between that of traditional PBT and LCP (GF30% standard), and is approximately twice the flow length of traditional PBT.

Figure 3 shows the molding conditions for a CPU socket mold for LCP (liquid crystal polymer). It is generally thought that stable molding of thin-wall products, for example less than 0.2 mm, is not possible using PBT. However, with SF3300, the CPU socket is completely filled, despite the fact that the mold is a 0.18-mm ultra-thin product. This indicates super-high flowability that cannot be achieved with standard PBT. Among all types of plastics, LCP exhibits the highest level of flowability, and the SF Series exhibits super-high flowability which rivals this level.

22th June 2017