Preparation method of high-air-permeability three-layer co-extrusion film

Abstract

The invention belongs to the technical field of breathable film preparation and intelligent manufacturing, and discloses a preparation method of a high-breathability three-layer co-extrusion film, which comprises the following steps: obtaining a film through an extruder, preheating the film, and then conveying the film to each traction roller in a stretching system for stretching; acquiring a thermal infrared image of the film in the stretching process; performing edge detection on the thermal infrared image to obtain an edge line and screening out a pore radiation area; and judging whether a pore radiation area with a hyperplasia trend exists in the thermal infrared image or not, and controlling the rotating speed of the traction roller, so that the stability of hyperplasia and expansion trend identification is improved, the whole film pores can be synthesized, the accuracy and precision of hyperplasia trend identification are improved, and the stretching speed limitation in the prior art is eliminated. The film stretching speed can be greatly improved under the conditions that the breathable film has a uniformly distributed microporous structure and the air permeability deviation is small.

Description

technical field [0001] The invention belongs to the technical fields of air-permeable film preparation and intelligent manufacturing, and in particular relates to a preparation method of a high-permeability three-layer co-extruded film. Background technique [0002] The breathable film is a kind of raw material such as polyethylene as the carrier, adding a certain amount of special calcium carbonate for blending, after extrusion into a film, and then directional stretching, because polyethylene is a thermoplastic material, it can be used in Stretching and crystallization are carried out under certain conditions. During stretching, interface peeling occurs between polyethylene and calcium carbonate particles, and interconnected pores or channels are formed around calcium carbonate, which gives the film a breathable function; In the preparation process of the breathable film, it is extruded into a film through an extruder, which is generally single-layer extrusion and single-s...

AI Technical Summary

Problems solved by technology

In stretch molding, a three-stage stretching method is adopted to achieve the stability of moisture permeability; Patent Publication No. CN108099148A discloses that by adjusting the amount of raw materials delivered to two extruders, two extruders are used to pass through the distributor. Divided into three layers, so that the processed raw materials can achieve three-layer co-extrusion, avoiding the use of three extruders to achieve three-layer co-extrusion, greatly improving efficiency; Stretching in the way of magnification avoids the risk of holes caused by excessive stretching in single-stage stretching. However, although these two methods can reduce WVTR fluctuations within a certain range, they are breathable due to breathability during film blowing and extrusion molding. The membrane body of the membrane is generally transparent, and it is difficult to visually identify the pore size of the air-permeable micropores on the air-permeable membrane. The pore size of the air-permeable micropores on the air-permeable membrane cannot be kept balanced, and it is prone to the problem that the local pore size is too small or too large. The unreliability of the area comparison of simple adjacent regions appears, the stability of the expansion trend recognition of the gas-permeable film proliferation is low, and there are limitations in the stretching speed of the stretching system in the existing technology, and the speed of film stretching Slow, once the speed is increased, the uniformity of the pores of the product cannot be guaranteed, so that the performance and quality of the product cannot be guaranteed, which will affect the performance and durability of the breathable membrane as a whole

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