In the molding of plastic products, black masterbatch has been used by almost everyone for dyeing, anti-aging, conductive products and so on. However, various problems often arise during use, which bother us. Xiao Bian will discuss some of the issues that people are concerned about today, hoping to bring you some gains.

part 1 The composition of  black masterbatch?

The materials that make up the black masterbatch are: A. carbon black, B. carbon black carrier, C. carbon black wetting agent, D. carbon black dispersant, E. other processing aids.

Part 2 black masterbatch used carbon black type?

According to the international classification, China has more than 30 varieties. Divided into two major categories, rubber and non-rubber. In carbon black for rubber, wear-resisting carbon black is mainly used, which can effectively improve the abrasion resistance of rubber tires. Among non-rubber-use carbon blacks, only black pigments can be obtained as black masterbatch.

The channel black is the most widely used in plastics due to its rich source, high purity and small particle size. Among them, it is divided into high-pigment carbon black (particle size 9-17mm), medium pigment carbon black (particle size 18-25mm) and low-pigment carbon black (particle size 26-37mm).

Due to the different carbon black varieties, the prices vary widely. Carbon black particles, because of their inherent activity, rarely exist as primary particles, and almost always agglomerated particles exist in a certain range of particle sizes.

part 3 What is the carbon black carrier?

The carrier is a material that carries carbon black. What raw materials are used for general plastic products and what raw materials the carrier uses. The black masterbatch thus produced has good compatibility with plastic raw materials. Such as: PS (polystyrene) plastic products, its use of black masterbatch carrier is PS. For polyethylene plastic products, the carrier is polyethylene.

However, LDPE (high-pressure polyethylene) is generally used because LDPE has the highest carbon black-bearing capacity and good processability. Other polyethylene HDPE and LLDPE can only produce low concentration black masterbatch. For PP (polypropylene) plastic products, only the black masterbatch with PP and LDPE as the carrier can be used, but black masterbatch of HDPE and LLDPE and other plastics can not be used. Of course, black masterbatch is also used as a carrier for recycled materials.

▲LDPE (high pressure polyethylene)

Part 4 Why does carbon black require a wetting agent?

The specific gravity of carbon black is about 2 g/cm. Due to the small particle size of carbon black, the density of the display is very small and appears fluffy and seems light. For smooth processing, carbon black must first be wetted. The choice of wetting agent is critical. In order to reduce costs, a large number of companies use products such as white oils or paraffins, which will seriously affect the strength of processed products.

What dispersants will be used for part 5 carbon black masterbatch?

It is mainly divided into organic dispersants and inorganic dispersants. The high-grade black masterbatch uses organic dispersants, which are mainly used for plastic products with high environmental requirements, such as drip irrigation products. Low-grade black masterbatch uses inorganic dispersant, commonly used calcium carbonate.

Judging from the masterbatch packaging, 25 kg of only half of the bag must use inorganic dispersants; full bags of black masterbatch using organic dispersants. The use of inorganic dispersants can greatly reduce the cost of black masterbatch, but it is very fatal that calcium carbonate has the effect of accelerating the aging of plastic products.

part 6 Does black masterbatch require processing aids?

Of course it needs. A smooth process requires the selection of the right antioxidants, internal lubricants, external lubricants, modifiers and antistatic agents.

part 7 What are the processing methods for black masterbatch?

There are three methods of processing: single-screw method, twin-screw method, and secret love method.

Single-screw method: After the materials are mixed by using a mixer, the single-screw extruder pulls the pellets, generally the concentration of carbon black is 18-20%, the process is backward, the production site has poor environmental conditions, and the process is eliminated. Some small start-ups still use this method for processing.

Twin-screw method: After the materials are mixed by using a mixer, the twin-screw extruder strips or water rings are used for granulation. Due to the limited mixing ability of the twin-screw machines, the carbon black concentration of the master batch is generally 25-32%.

The smelting method: After the materials are mixed by using a mixer, they are fed into a twin-screw extruder after being kneaded by an internal mixer and then fed into a twin-screw extruder through a water ring or underwater. The concentration of carbon black in the masterbatch is 40- 45%.

 part 8 Does theprocessing method affect the masterbatch performance?

Definitely. Among them, the smelting method can increase the carrying capacity of the carrier to carbon black, and the carbon black can enter the carrier more evenly. The advantages of kneading by mechanical mixing of the mixer, crushing of agglomerated particles, and agglomeration of the carbon black particles are greatly reduced, and the particle size and distribution of the carbon black in the masterbatch are equal, which cannot be replaced by the other two methods.

Part 9 black masterbatch in which aspects have outstanding performance?

In the dyeing of plastic products, black masterbatch only 0.6% -0.8%, it will be very strange black, and more will not be more black. According to test data, products used in outdoor areas in Xinjiang, such as the need to rely on black masterbatch to prevent aging, as long as the use of high-quality black masterbatch (instead of back material as carrier, white oil wetting, calcium carbonate dispersion, etc. black masterbatch ).

Carbon black in the product content of 2-2.5%, that is: per 100 kilograms of raw materials, there are 5-6 parts by weight (carbon black), 40% of the masterbatch, which plays a role far more than any anti-aging products, Product life can reach more than 10 years.

This is why drip irrigation products, water transportation products, and communication cable products are all black. In addition, carbon black has a special contribution to the increase in product strength, conductivity enhancement and so on.

▲ black masterbatch applied to the pipe

Part 10 does not seem to use so many black masterbatch in actual production?

That's right. In actual production, about 2 parts of black masterbatch are generally used, and then an anti-aging aid is added, and the anti-aging and anti-aging effects of carbon black are utilized to reduce the product cost. In addition, the length of outdoor use, product life requirements, but also determine the appropriate use of black masterbatch, the premise is that carbon black in the product must form a continuous phase, that is, carbon black "film" protection of plastic.

If too little black masterbatch is added, the carbon black phase (ie, the high concentration of small pieces) is discontinuous in the product. At the boundary between the phases and the phases, the plastic molecules are most fragile and are directly hit by the ultraviolet light to accelerate the oxygen aging reaction. When the carbon black is like impurities in the product, it is better not to add it. When the phase and phase boundaries are less than 280mm, the UV light can be avoided and the product is safe.

part 11 How does  judge its quality from the appearance of black masterbatch?

Good quality black masterbatch luster and moderate hardness. If the oil is too bright, it means that the oil is put too much, and the dull gloss indicates that the carrier is back or the calcium carbonate is excessive. Good quality black masterbatch with teeth bite, soft with crisp.

Too soft means that too much organic dispersant, soft and loose means that the concentration of carbon black is low, calcium carbonate is more, too brittle means that the content of carbon black is too high, or the carrier is back.

part 12 What is the effect of using a black masterbatch on the surface of the product?

If the pockmark is a protruding tip, it means that the product processing equipment has a limited ability to disperse the masterbatch, and the carbon black aggregate particles in the masterbatch cannot be sheared uniformly, and a lower concentration of black masterbatch should be used; or the masterbatch has too much carbonic acid Calcium and excessive white oils are extruded by single-screw and twin-screw extruders under high pressure to form small deadlocks that cannot be dispersed. If the pockmark is concave, it is caused by the volatilization of small molecules in the masterbatch, indicating that there is more white oil.

Part 13 Can a black masterbatch containing calcium carbonate be used?

Take a comprehensive look. First of all, if the black masterbatch has a calcium carbonate fineness of 1000 mesh and a content of less than 10%, it is a good choice for products that require no outdoor exposure, and the price is low. The appearance of the product is good gloss, the carbon black is uniformly dispersed in the process, the blackness is not affected, and the effect on the strength of the product is small.

If the calcium carbonate fineness is less than 1000 mesh, gloss may appear dull, the surface roughness, and the strength of the product may decrease. If the amount of 1000-calcium carbonate used exceeds 10%, the surface of the product will have no light graying, the blackness will be insufficient, and the strength of the product will decrease.

Secondly, calcium carbonate is not good for any outdoor use product with anti-aging requirements, depending on the product's service life.

Yancheng Ruize Masterbatch Co., Ltd. mainly produces and operates: Non-woven masterbatch, Non-woven antibacterial masterbatch,antistatic masterbatch, polypropylene filament masterbatch, Polypropylene filament masterbatch, Non-woven masterbatch,  polypropylene spunbond non-woven masterbatch, Polypropylene fiber masterbatch, chemical masterbatch, Non-woven masterbatch, polypropylene masterbatch, Soft hydrophilic masterbatch.