How to Choose Nonwovens Masterbatch in Nonwovens Production

Spunbond nonwovens is the fastest growing variety in the nonwovens industry, accounting for about 40% of the total nonwovens. Polypropylene as the raw material of spunbond non-woven products are widely used in medical materials, health materials, furniture fabrics, carpet fabric, decorative materials, protective materials, automotive industry and so on.

Polypropylene is a pure linear saturated hydrocarbon polymer, macromolecules without polar groups and active groups, with a high degree of chemical stability. Polypropylene fibers have high crystallinity, dense structure, and strong hydrophobicity. These characteristics make it difficult for polypropylene to provide stained seats, which can not or can not diffuse into the interior of the dye. Therefore, in order to improve the practicality and aesthetics of the polypropylene nonwoven fabric, the masterbatch spinning method is used in the production. In this paper, the influence of masterbatch on the production of spunbond nonwovens was analyzed.

The composition of the masterbatch The choice of masterbatch is the pigment in 20% to 80% of the proportion of grinding or twin screw extruder evenly dispersed in the resin and the color particles obtained, with excellent coloring effect, easy to automatically measure and Transportation, energy conservation, no dust, no pollution and so on. International masterbatch market concentrated in the United States, Western Europe, Japan, China's masterbatch manufacturers are mainly distributed in Guangdong, Zhejiang, Jiangsu, Shandong, Beijing, Shanghai and other provinces and cities. In the production of spunbond polypropylene, the composition of the masterbatch is mainly from the following aspects.

1, the pigment: the pigment is the main component of the masterbatch, mainly inorganic pigments Received Date: 2007.03-02 and organic pigments two categories. Inorganic pigments are generally metal oxides, sulfides or metal salts, have good light resistance and weatherability, which for the poor light resistance of polypropylene resin is of great significance. The shortcomings of the larger particle size; organic pigments with strong coloring, good dispersion, bright color and other advantages, but in the light often will cause saturation decline, easy to cause coloring products fade, it is recommended to use the appropriate particle size of inorganic pigments The The heat resistance of the pigment refers to the temperature at which the color or performance of the pigment changes at the production or use temperature, and the heat resistance of the pigment is about 250 ° C. At this time, the color difference of the colored product is small; Grade, light resistance 6 ~ 8, with the polypropylene resin has good compatibility, and other additives in the synergistic, in the spinning process coloring solid; for medical and maternal and child supplies, the pigment can not contain Hazardous heavy metals such as cadmium, lead, mercury and so on. Pigment particle size directly affect the degree of dispersion of pigment and finished product performance, if the pigment particle size is too small, the specific surface area, the surface free energy will be large, easy to accumulate into the group, resulting in its dispersion in the polypropylene resin uneven; Pigment particle size is too large, it will plug the filter plate and spinneret in the production, so that the fiber in the hair when the hair and broken the phenomenon of increase, and even make the resin or additives due to the residence time is too long and cause thermal decomposition, Affect the physical and mechanical properties of fiber. The average particle size of the pigment particles is controlled between 0.1 and 0.5 / 1m.

2, the carrier: the carrier is the matrix of masterbatch, masterbatch can be granular, accounting for 30% to 50% masterbatch, the carrier should be with the pigment has a good affinity and compatibility, select the carrier Consider the compatibility with the colored resin and its impact on other properties of the coloring system.

As the spunbond spinning speed is large, the molecular weight of the carrier and its distribution requirements are more stringent, it is recommended to use the melt index of about 2010min metallocene catalyst synthesis of polypropylene. The molecular weight distribution coefficient of the polypropylene synthesized by metallocene catalyst is less than 4, which can effectively improve the coordination and dispersibility of the pigment in the masterbatch. The coloring of the finished product is strong, the beauty is enhanced and the physical and mechanical properties can be improved. For 80% of the high concentration of masterbatch, reduce production costs.

3, the dispersant: dispersant can be wrapped in the surface of the pigment particles, reducing the surface energy of the pigment free energy, the pigment dispersed into fine, stable particles and evenly distributed in the melt, and in the processing process does not occur reunion. Usually require dispersants and pigments with good affinity, and the carrier has a good compatibility. From the economic efficiency and practicality, it is recommended to use polypropylene wax as the dispersant, its softening point is high, the molecular weight distribution is narrow, no smell, can significantly improve the mastering ability of the masterbatch, reduce the color difference, reduce the spinning broken wire, phenomenon. The most commonly used dispersants are powders, flakes and the like. Ordinary wax particles were significantly larger than the pigment particles, the pigment particles wrapped uneven, it is recommended to use fine powder wax. The particle size of the fine wax is close to the size of the pigment, and the filling of the wax particles into the pigment particles allows the pigment particles to maintain a certain distance and provide a wetting effect, which can remarkably improve the dispersibility of the pigment.