In the molding process of plastic products, almost everyone has used black masterbatch for dyeing, anti-aging, conductive products and so on. However, various problems often appear during use, which bother us. Today, the editor will discuss some issues of common concern to everyone, hoping to bring you gains.
9: Where should the black masterbatch have outstanding performance? In the dyeing of plastic products, the black masterbatch only needs 0.6%-0.8%, it will be extremely black, and it will not be blacker if you add more. According to test data, for products used outdoors in Xinjiang, if you need to rely on black masterbatch to prevent aging, you only need to use high-quality black masterbatch (not the regrind as a carrier, white oil wetting, calcium carbonate dispersion, etc.) ). The content of carbon black in the product reaches 2-2.5%, that is: every 100 kg of raw materials, there are 5-6 parts (by weight) of the masterbatch containing 40% of carbon black, which far exceeds any anti-aging product. Product life can reach more than 10 years. This is why drip irrigation products, water delivery products, and communication cable products are all black. In addition, carbon black has a special contribution to the increase in product strength and conductivity.
10: It seems that there are not so many black masterbatch used in actual production? That's right. In actual production, about 2 parts of black masterbatch is generally used, and anti-aging additives are added to use the synergistic effect of anti-aging and carbon black to prevent aging to reduce product costs. In addition, the length of outdoor use and product life requirements also determine the appropriate reduction in the amount of black masterbatch used. The premise is that the carbon black must form a continuous phase in the product, that is, there is a carbon black "film" to protect the plastic. If too little black masterbatch is added, the carbon black phase (that is, the part with high concentration of small pieces) is discontinuous in the product. At the boundary between the phase and the phase, the plastic molecules are the most fragile and are directly hit by ultraviolet light, which accelerates the oxygen aging reaction. When carbon black is like an impurity in the product, it is better not to add it. When the boundary between phase and phase is less than 280mm, it can avoid the impact of ultraviolet light and the product is safe.
11: How to judge the quality of the black masterbatch from its appearance? Good quality black masterbatch has moderate gloss and hardness. If the oil is too bright, it means that the oil is put too much, and the gloss is dim, which means that the carrier is recycled material or excessive calcium carbonate. Good quality black masterbatch is bitten with teeth, soft and brittle. Too soft means too much organic dispersant, soft and loose means low carbon black concentration and more calcium carbonate, too brittle means too high carbon black content, or carrier is recycled material.
12: After using the black masterbatch, what is the problem with the small pitted surface on the surface of the product? If the pitted surface has small protruding tips, it means that the product processing equipment has limited ability to disperse the masterbatch and cannot evenly shear the carbon black aggregate particles in the masterbatch. Black masterbatch with a lower concentration should be used; or the masterbatch has too much calcium carbonate and too much white oil, and is extruded by a single-screw or twin-screw machine under high pressure to form small rigid blocks that cannot be dispersed. If the pitted surface is concave, it is caused by the volatilization of small molecules in the masterbatch, indicating that there is more white oil.
13: Can the black masterbatch containing calcium carbonate be used? Take a comprehensive look. First of all, if the calcium carbonate in the black masterbatch has a fineness of 1000 mesh and the content is within 10%, it is a good choice for products without outdoor exposure requirements, and the price is low. The appearance of the product has good gloss, the carbon black is evenly dispersed during processing, the blackness is not affected, and the product strength is less affected. If the fineness of calcium carbonate is less than 1000 mesh, the gloss may be dull, the surface may be rough, and the strength of the product may decrease.
If the amount of 1000 mesh calcium carbonate exceeds 10%, the surface of the product will be dull and gray, the blackness will be insufficient, and the strength of the product will decrease. Secondly, in any outdoor products with anti-aging requirements, it is not good to contain calcium carbonate, depending on whether the product is used or not.