PBT and PET engineering plastic flame retardants, how do you choose?

Selection and application of PBT and PET engineering plastics flame retardants

PBT and PET(Linear polyester)PBT and PET are two important engineering plastics, widely used in the electronics, instrumentation and automotive industry, its flame retardant products are used in parts with high flame retardant requirements. Their flame retardant treatment is as follows:

(1) Adding brominated flame retardants are commonly used decabromodiphenyl ethers, brominated polystyrene (BPS), brominated epoxy resin (BER), double (tribromophenoxy) ethane and so on.

For example, adding 10%-15% bromine flame retardant and 3%-5% antimony trioxide can make the PBT containing 30% glass fiber reach the UL94 V-0 level, and the oxygen index can reach 27%-29%. The use of added flame retardants must pay attention to the dispersion and easy seepage in PBT and PET, as well as the impact on the luster and mechanical strength of polyester.

(2) The addition of bromo-containing phosphate esters is commonly used in tri (dibromo-phenyl) phosphate (TDBPPE), because the same molecule contains Br and P elements, so it has halogen-phosphor coordination effect. The flame retardant efficiency is very high in PBT and PET.

It should be noted here that the flame retardant treatment is often added; If the oxygen index is tested, then the limiting oxygen index will be increased, but in the oxygen-rich test environment, Sb and P seem to have a antagonistic effect. Therefore, the UL94 vertical combustion method is the most appropriate method to evaluate the flame resistance of the system.

(3) Flame retardant PET is used as flame retardant fibers and fabrics.

There are usually two ways to do this:

The first is to use hexabromocyclododecane to flame retardant PET fabric after treatment. This fabric can be used as curtains, curtains, wall covering and other interior decoration cloth. Because it is processed by the post-finishing method, the flame retardant is easy to ooze, and the fabric feel and flame retardant durability will be inferior.

The second is flame retardant modification by copolymerization. These reactive flame retardant monomers are mainly bromine aromatic compounds, aryl phosphine oxide compounds, and bromine aryl phosphine oxide compounds. Because it is a part of the flame retardant element that becomes the center of the oligomer molecule, it has the advantages of long-term flame retardant effect, good feel, light resistance and so on, and is the main flame retardant method for PET flame retardant fibers and fabrics in China today.