Johns Manville supplies polypropylene meltblown for liquid filtration applications in numerous weights from 15 to 200 grams per meter squared with Mean Flow Pore Size ranging from 0.5 to 45 micron. However, there are applications where polypropylene is not an acceptable material. For those applications, which are appropriate, Johns Manville provides polybutylene teraphthalate (PBT) polyester as an alternative.
PBT polyester will provide a different set of chemical and thermal resistance than polypropylene, for specific applications, but the principal difference from polypropylene, is that PBT is resistant to degradation caused by radiation. Materials produced with PBT polyester can be sterilized by gamma irradiation in the finished product form, as opposed to autoclaving, which may not be possible for the finished product. PBT can also be used in applications where radiation may be present and polypropylene would be unacceptable.
For applications where polyethylene teraphthalate (PET) is not desirable because of possible antimony contamination, the PBT can be employed since no antimony catalyst is used in its production.
Being an "engineered plastic", the PBT polyester is produced with tight control of the molecular weight distribution. This allows for, the production of meltblown webs, which can have narrow pore size distribution, allowing the material to tailored to the specific filtration application.
Currently the PBT material is supplied in weights from 10 to 200 grams per meter squared and Mean Flow Pore sizes from 1 to 40 microns, as meltblown and single layer and multi-layer calendered meltblown rolls.
JM currently supplies PBT meltblown webs in weights ranging from 10 to 200 grams per meter squared, and mean flow pore sizes from 1 to 40 microns. The webs are available as meltblown, single-layer and multi-layer calendered rolls. Johns Manville has commercialized the recently expanded PBT (Polybutylene Teraphthalate) meltblown products for liquid filtration.
PP, the most widely used polymer, does not always provide the chemical and thermal resistance required. In such applications, PBT could be the polymer of choice. PBT can be sterilized by gamma irradiation and does not exhibit antimony contamination, as does PET (polyethylene teraphthalate).
As an "engineered plastic", PBT polyester is produced with tight control of the molecular weight distribution, which enables the production of meltblown webs with narrow pore size distribution. This results in webs tailored to specific requirements.
