The relationship between the quality of color masterbatch and the quality of polypropylene fiber

The masterbatch industry has also developed significantly with the development of related industries, and the production technology level of masterbatch has made unprecedented progress. The application fields of masterbatch are also constantly expanding. However, due to the influence of the traditional market competition model in China, the pursuit of "low quality, low price, and usability" is often pursued, resulting in unstable production, low quality grades, and weak product competitiveness of downstream masterbatch application enterprises. This issue has been widely recognized by many masterbatch application manufacturers, especially polypropylene manufacturers with high quality requirements, who pay more attention to the impact of masterbatch quality on polypropylene quality. Therefore, according to the requirements of the Polypropylene Chemical Fiber Industry Association, this article discusses the influence of color masterbatch on the quality of polypropylene fiber

1、 Dispersion of Color Masterbatch in Polypropylene Fiber
The polypropylene fibers with various colors are caused by the uniform dispersion of pigment particles in the polypropylene fibers, and the key is that the pigment particles are fully refined and evenly distributed (mixed) in the polypropylene fibers. Fine dispersion is the process of thoroughly refining pigment particles and evenly distributing (mixing) them within polypropylene fibers. Fine dispersion is the process of breaking down the aggregates or round bodies of pigments to minimize their particles, with the key being uniform dispersion. The dispersion effect has an impact on the luster, transparency, luster, fiber strength, elongation, aging resistance, and electronegativity of colored polypropylene fibers.

Generally speaking, pigments with a dispersed particle size of less than 1um can be used for fibers or ultra-thin films, while particles larger than 5um can cause problems with the fiber surface** Xun Xiang? Exceeding 10um will cause spots and streaks on the surface of the fiber, and the fracture strength and elongation of the fiber will continuously decrease as the particle size increases. The finer the particle size, the stronger the coloring power, and the better the dispersibility. At the same time, the smaller the particle size, the larger the surface, resulting in an increase in covering power.

Due to the three types of pigment particle states: primary particles, aggregates, and aggregates, and the fact that general commercial pigment particles are larger than the aggregates (about 75-250um), dispersion treatment is necessary. The so-called pigment dispersion is the process of crushing and refining the aggregates.

The dispersion of pigments is first achieved by wetting the pigment with a wetting agent, coating it on the surface of the pigment, reducing the cohesion between pigments and lowering the energy required to break the pigment agglomerates. Secondly, the pigment is finely ground, leading to free movement between pigment particles (impact stress) and breaking the agglomerates through the shear stress of the surrounding medium. After the pigment is dispersed and refined, the particle size decreases, the surface area increases, and the surface free energy of the pigment also increases, causing instability of the refined pigment. Therefore, further coating treatment is needed on the surface of the pigment to reduce the newly formed interfacial surface energy and prevent re aggregation. Then, the pigment is mixed and dispersed in the melt, that is, the wet and crushed pigment is uniformly dispersed and distributed into the material that needs to be colored.