It was so hard to make a high-gloss PP product – there are actually pockmarks on the surface! What should I do?
Pitting may seem like a minor issue, but it directly affects the appearance and texture of the product. Especially in high-gloss applications like the shells of home appliances, even the slightest flaw can significantly reduce the overall grade. So, where exactly do these pockmarks come from?
🔍 There are two main reasons:1. Insufficient melt index → The filler cannot disperse
If the melt index (MI) of PP resin is low, its fluidity will deteriorate, the filler cannot be evenly dispersed, and it is prone to agglomeration and the formation of pitting.
2. The packing material is too rough → the surface is difficult to be smooth and bright
Traditional fillers such as talcum powder and calcium carbonate have relatively coarse particles or irregular shapes. Even if the addition amount is not large, they are prone to disrupt the continuity of the surface, causing light scattering and the appearance of fine pockmarks.
💡 Then how can we solve it at its root?The first step: Select the right substrate
It is recommended to use homopolymer PP with a high melt index and avoid copolymer PP. Homopolymer PP has a higher crystallinity and its surface is easier to be made bright and smooth. Copolymer PP, due to the presence of ethylene segments, usually has a slightly inferior surface gloss.
Step 2: Select the right packing material
It is strongly recommended to use ultrafine modified barium sulfate (fineness suggested above 3000 mesh).
It has good compatibility and dispersibility and is not prone to agglomeration.
The particles are fine and uniform, without affecting the surface flatness.
Especially after surface modification treatment, barium sulfate has a stronger bonding force with PP and can also improve the fluidity of the overall material.
New application of barium sulfate:We offer modified barium sulfate developed with high-gloss PP, which has effectively helped many enterprises solve the problem of pitting. It is widely used in scenarios such as home appliance shells and high-end daily products, truly achieving a “shiny to the point of reflection” texture effect.
If you are also troubled by the pitting problem on the PP high-gloss surface, you might as well start by adjusting the materials and fillers. Welcome to exchange and consult!
Get samples for free
