Cast film anti-blocking masterbatch formula composition

What is the composition of an anti-blocking masterbatch?  The anti-blocking masterbatch is composed of carrier resin, filler, and auxiliaries. In the process of forming, the ratio of the anti-blocking masterbatch and matrix resin must be adjusted according to the content of relevant components in the masterbatch and the amount needed to be added to the actual product.

Anti-blocking masterbatch refers to the process of plastic processing and molding, to facilitate the operation, will need a variety of anti-blocking agents, filler, and a small amount of carrier resin are mixed and mixed first, the prepared particle is called anti-blocking masterbatch.

The main role of salivary membrane anti-blocking masterbatch

The anti-blocking masterbatch is composed of carrier resin, filler, and auxiliaries. The limit of additives or filler content in the anti-blocking masterbatch is several times to ten times higher than the amount required in the actual plastic products.

In the process of forming, the ratio of the anti-blocking masterbatch and matrix resin must be adjusted according to the content of relevant components in the masterbatch and the amount needed to be added to the actual product. Master materials can usually be divided into organic anti-blocking masterbatch and silica anti-blocking agents.

The main components of the anti-blocking masterbatch are silica and erucic acid amide. Selection of raw and auxiliary materials for anti-blocking masterbatch: polyolefin anti-blocking masterbatch is composed of three parts: carrier resin, filler, and anti-blocking adjuvant, of which filler accounts for an important component, up to 90%.

Generally, when selecting raw and auxiliary materials with anti-blocking masterbatch, it is necessary to consider their good application performance and low cost.

The main filler used for anti-blocking masterbatch is calcium carbonate, followed by talc powder, kaolin, wollastonite, and other inorganic filler. For any inorganic filler, particle size and particle size distribution are the main technical index. Generally, the smaller the particle size and the narrower the distribution, the better the filling effect.
In addition, the filling effect is also related to dispersion, the smaller the particle size, the more difficult the dispersion, and the higher the price. Purity is another main technical index of inorganic filler, the less impurity content, the higher purity, the better.
In the general selection of heavy calcium carbonate selection, its content should be as high as possible, with the general requirement of more than 94%. Ensure that other indicators meet the requirements, and the price is low, to reduce the cost of the master stock.

The application performance and cost of polyolefin filler master stock are important depending on the carrier resin, usually, according to the use of the master stock, the content of the carrier resin is generally 10%-20%. The carrier resin used to fill the master batch of polyolefin shall have good compatibility with the plastic matrix resin to be filled.

From this aspect, the general carrier resin is the best to choose matrix resin. In addition, the selection of filler carrier, but also considering its melting point and melt liquidity, the melting point of the carrier resin shall not be higher than the matrix resin.

At present, some enterprises are still using LDPE (1f7b) as the carrier resin, which is important because this brand of resin has a low melting point and a high melt flow rate (7g/10min).

However, the high melting temperature of polypropylene (20~40℃ higher than the general polyethylene) limits its application in polyethylene plastics, and the melting point of random polypropylene or powder polypropylene synthesized by liquid phase bulk method does not exceed 100℃, so it is widely used as the carrier of anti-blocking masterbatch.

LDPE (1f7b) is an anti-blocking masterbatch carrier resin, its biggest advantages are low melting point, high melt flow rate, and high melt strength, but the outstanding disadvantage is its high price. If low-density polyethylene resin with a low melt flow rate and low cost is selected, such as 1i2a-1 or 2f2b, etc., due to their low melt flow rate, generally about 2g/10min, more paraffin wax and other additives need to be added during processing, to facilitate better dispersion of masterbatch in matrix resin.

Usually using polyethylene is the carrier to make the filler masterbatch, more suitable for polyethylene plastic products, the important reason is that the carrier resin and matrix resin performance is the same, with good compatibility. The filling master material for polyethylene film has higher and stricter requirements on the carrier resin.

For polypropylene products of the anti-blocking master, the carrier resin is the best polypropylene. Theoretically, atactic polypropylene is the best because of its low melting point, good melt mobility, and good dispersion. But detailed to China’s national conditions, the choice of liquid phase ontology synthesis of powdered polypropylene is more appropriate, because of its low price, it is powdered, and easy to mix with inorganic filler evenly, even in the hopper will not be stratified.

Polypropylene was used as the carrier. Due to the poor thermal stability of polypropylene, an antioxidant and smoothing agent must be added at the same time. To make only a few thousandths of the total resin additives can be evenly distributed in the resin, it is best to mix the resin and various additives evenly, and then mix granulation with the filler in a certain proportion.

Recycled polystyrene is widely used in the synthetic leather manufacturing process, even though the compatibility between the carrier resin and the matrix resin is not good enough, the carrier resin has far less effect on the performance of plastic products than the filler, which can bring considerable economic benefits.

The additives used in polyolefin filler masterbatch are dispersants and surface treatment agents. The function of the dispersant is to improve the masterbatch processing fluidity and facilitate the masterbatch to disperse more evenly in the matrix resin. Commonly used dispersants are white oil (liquid paraffin), paraffin, dioctyl phthalate (bop), low molecular weight polyethylene (polyethylene wax), and stearic acid.

The important properties of commonly used dispersants can be selected according to the properties of filler and carrier resin. Surface treatment agents can change the surface activity of inorganic filler, making it from hydrophilic to lipophilic, to facilitate and carrier resin mixing, an important coupling agent, and stearic acid two classes.

The processing technology and related equipment of polyolefin filling masterbatch change with the change of carrier resin.

Mixing – anti-blocking refining – water-cooled grilling, intermittent production, application equipment is mixing machine, anti-blocking refining machine, and plate grilling machine.

The second generation of anti-blocking masterbatch is LDPE (1f7b) as the carrier resin, the produced masterbatch is called PEP masterbatch. The process must use a large aspect ratio, and high mixing performance of the extraordinary design of the single screw extruder, to obtain better results.

The second generation of anti-blocking masterbatch is LDPE (1f7b) as the carrier resin, the produced masterbatch is called PEP masterbatch. The process must use a large aspect ratio, and high mixing performance of the extraordinary design of the single screw extruder, to obtain better results.