ASO Co., Ltd.

 Organic additives such as antioxidants and lubricants always have the problem of bleed-out. Inorganic additives such as anti-blocking agents have the problem of release from the film.

 Bleed-out is the aggregation and solidification of various additives in the film volume over time, causing them to migrate to the film surface and form a powder.
You may have seen powdery substances or white spots on the surface of bags during long-term storage.
 This phenomenon is more noticeable with LLDPE, which is catalyst-polymerized.
As mentioned in the previous section, LLDPE is catalytically polymerized, so stearic acid and calcium chloride are separately present in the film volume.
 

 In addition, LLDPE has a smoother film surface than LDPE, so the amount of added lubricants and anti-blocking agents tends to be higher than in LDPE.
  Therefore, LLDPE is more often subject to complaints due to bleed-out during long-term storage.

 The particle size of the powder is not constant and depends on the agglomeration situation, varying from submicron order to more than 40 μm in size.
 We have measured the number of particles inside a bag, which is generally around 500 mm wide and 700 mm long, and found that LLDPE bags contain several million particles of 2 μm or larger on the entire inner surface, while LDPE bags contain several hundred thousand particles of 2 μm or larger. (However, these figures vary depending on the bag size, raw material production conditions, melt temperature, inflation air control, and raw material grade.)