The Shenzhen Polymer Industry Association officially released the group standard of "Special Polypropylene (PP) for Meltblown Medical Masks" (T/ SGX 001-2020) on May 15, 2020, which will be implemented on June 15, 2020.
  The standard was formulated by the Shenzhen Polymer Industry Association and jointly developed by 19 upstream and downstream companies that produce melt-blown materials, melt-blown cloths and medical masks. It passed the expert review on May 13, 2020.
  Compared with existing standards:
  First, the existing standard only involves six technical indicators: appearance, melt mass flow rate, volatile matter, ash, molecular weight distribution and residual amount of di-tert-butyl peroxide. The group standard has been increased to 11 technical indicators, respectively increasing the density, melting point, odor, n-hexane extract and xylene extract 5 indicators, and appropriately improved the original 4 indicators.
  Second , the group standard has special medical indicators. On the basis of the national standard, three indicators were added: odor, n-hexane extract and xylene extract.