Introduce the quality requirements for polypropylene plastic masterbatch

The quality indicators of color masterbatch include many contents. The appearance size is generally 2mm × (3-4) mm, and the pigment particle size in the color masterbatch is less than or equal to 1 um, accounting for 90% or more. The melting point, DF value, MI value, heat and weather resistance characteristics, etc. These indicators are of common concern to both masterbatch factories and polypropylene fiber factories. The following content is provided by Shenzhen Yusiwei Company, hoping to help everyone:

1. The melt flow index (MI value) of polypropylene slices is mainly used to characterize their molecular weight, determine their processing and finished product properties after slicing into fibers. Color masterbatch contains pigments, dispersants, and low molecular weight polyethylene wax carriers, so the MI value cannot be used to determine its own molecular weight and may vary depending on the pigment and variety. Therefore, the MI value of color masterbatch is not a control indicator for color masterbatch and can only be used as a reference during spinning. The MI of the spinning masterbatch is slightly larger than that of the natural color slice, which is beneficial for mixing the two with similar particle size. The general requirement is an MI value of (15-30) g/30 min.
2. The heat resistance index of heat-resistant masterbatch refers to the degree of color change observed by spinning masterbatch and polypropylene slices in a certain proportion at different temperatures for 5-10 minutes. The color change can be evaluated by comparing the gray sample card or color sample card. When the total color difference value Δ E ≤ 3, this temperature is the heat-resistant temperature of this color masterbatch, which generally requires a heat-resistant range of 270-300 ℃ and a color change of level 4.
3. The weather resistance of colored polypropylene fibers is determined by referring to the test method for sun fastness of textiles. The results are evaluated using the blue standard for assessing sun fastness, which requires a sun fastness level of 5, but in fact, it is mostly between levels 6 and 8.
4. Fiber grade color masterbatch is characterized by its filtration performance, which is called the DF value. If the DF value is small, the replacement cycle of the filter components during the spinning process is relatively long. Generally, the DF value of polypropylene color masterbatch is required to be less than 2.0 × 105Pa · cm2/g
5. The dispersant for polypropylene color masterbatch uses low molecular weight polyethylene wax, so its melting point is between 110-120 ℃; And pigments generally have a high melting point, exceeding the spinning temperature of polypropylene, so color masterbatch has two endothermic peaks on the thermal analysis spectrum. However, the melting point of color masterbatch cannot characterize the quality of color masterbatch. Some enterprise standards stipulate a melting point of 130-160 ℃