Production process of high-melt-index polypropylene melt-blown material

Abstract

The invention discloses a production process of a high-melt-index polypropylene melt-blown material, and belongs to the technical field of respiratory protection material production. The production process comprises the following steps of mixing polypropylene powder and a peroxide composite degradation agent, adding into a twin-screw extruder, adding an additive, uniformly mixing, reacting in a screw reaction section of the twin-screw extruder, carrying out melt extrusion, and adding a long-acting stabilizer and a short-acting stabilizer at the tail end of a screw of the twin-screw extruder to obtain a material; and conveying the obtained material to a cooling water tank for cooling through an inclined water tank, air-drying through an air dryer, granulating in a granulator, and screening through a vibrating screen, so as to obtain the high-melt-index polypropylene melt-blown material. The high-melt-index polypropylene is obtained through a composite degradation method, no degradation agent is left in the melt-blowing production process, and the produced non-woven fabric is free of peculiar smell and yellowing.

Description

technical field [0001] The invention belongs to the technical field of respiratory protection material production, and in particular relates to a production process of high melting point polypropylene meltblown material. Background technique [0002] In recent years, with the rampant spread of respiratory infectious viruses (such as Ebola virus, SARS virus, etc.), public health issues have received attention from all walks of life. Especially in 2020, the new coronavirus spreads globally, posing a huge threat to human life. Medical masks and protective clothing have become important protective equipment to prevent the spread of the virus and protect the health of the population. The medical mask is composed of three layers of non-woven fabric, the finish and inner layer are made of spun-bonded non-woven fabric, the middle layer is made of melt-blown non-woven fabric, and polypropylene melt-blown material is used as the main material of melt-blown non-woven fabric The raw ma...

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Problems solved by technology

[0003] At present, the methods for preparing high melting point polypropylene are as follows: one is to control the molecular weight and molecular weight distribution of polypropylene by controlling the polymerization process, such as reducing the molecular weight of the polymer by increasing the concentration of a polymerization inhibitor such as hydrogen, thereby increasing the melt index. However, this method is limited by the catalytic system, reaction conditions and other factors, and the stability of the melt index is difficult to control; the second is to control the degradation of polypropylene obtained by conventional polymerization, reduce its molecular weight, and increase the melt index. In the past, high-temperature degradation methods were commonly used To reduce the molecular weight of polypropylene, but this high-temperature mechanical degradation method has many disadvantages, such as additive loss, thermal decomposition, process instability and other unfavorable factors. In addition, there are methods such as ultrasonic degradation, but these methods often require the presence of solvents , which increases the difficulty and cost of the process, and the chemical degradation method widely used in recent years is to make polypropylene and chemical degradation agents such as organic peroxides react in the screw extruder, but peroxides can degrade low-melting It means that the polypropylene process is too late to degrade 100%, the degradation reaction cannot be completely completed, and the residual peroxide will stay in the high-melt polypropylene raw material, resulting in non-woven fabric odor, yellowing, unstable performance, and affecting non-woven fabrics. quality

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