... .60g/cm3, relatively density 1.4 g/cm3, refractive index of 1.544 (20 C), water absorption ≤ 0.5 %. ... concentration of hydrochloric acid, 90% or less of sulfuric acid, 50% ~ 60% of nitric acid and 20% or less of the caustic soda solution, stability of the ... screen hole≥ 95Pearleye number,grain/400c≤ 20Absorbing volume(g) of elasticizer/100g PVC resin≥ 19White degree (160,10minlater),%≥ 78Rudimental ...