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• Time of issue:2020-11-25
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(Summary description)With the maturity of the initial processing of non-woven fabrics, more and more companies are turning their attention to the deep processing of non-woven fabrics in order to maximize the added value of products and increase the profits of enterprises. In China, the application fields of hot melt coating equipment have also been continuously expanded. The medical and sanitary material production sectors are the most widely used industries of this type of equipment. The rapid development of the automobile industry in China has also stimulated the According to the demand for coating equipment, relevant data show that the domestic geotextile industry recently introduced the first hot melt production line so far. As a mature and constantly developing process, the prospect of hot melt coating technology in the deep processing industry of non-woven fabrics will get better and better. Disposable medical supplies (such as surgical gowns, surgical sheets, wet wipes, gloves, shoes, hats, etc.), industrial protective products, and personal care products are mainly non-woven composite film products. These industries have The requirements are almost the same, namely waterproofness, breathability and comfort. This article will analyze and compare several main technological characteristics of current medical and sanitary material composites: 1. Laminating: This kind of technology is the most used method in domestic enterprises. Features: simple, mature, and fast production speed ( About 100m/min). Disadvantages: Do not make products that require breathability; feel hard and have poor comfort; higher requirements for non-woven fabrics. Non-woven fabrics with low weight (below 18gsm) and low coating weight (below 15gsm) have unsatisfactory coating effect, because the unevenness of the surface of the coil makes the coating process prone to leaks. 2. Hot rolling: It is the standard process for the two-step manufacturing of SMS non-woven fabrics. Many domestic companies use this process for composite manufacturing of films and cloths. Features: ready-made equipment and technology can be used. Disadvantages: The composition of the film is PE, and the composition of the non-woven fabric is polypropylene. The different melting points of the two make the temperature of the hot roll cannot be considered at the same time; the heat capacity of the hot roll causes different production speeds at the same temperature to lead to the uniformity of the composite strength of the product Poor; the processing accuracy of the hot embossing roll is also a factor that affects the quality of the product; the hot rolling method has a higher air permeability loss rate for the air permeable film material (between 30-40%); the production speed is slow. 3. Cloth powder compounding: A method of evenly sprinkling hot melt adhesive powder on the non-woven fabric or film, and then compounding by heat. Features: The heat pressure roller uses rubber band roller and smooth roller to cause little damage to the material. Disadvantages: slow production speed and low production efficiency; even distribution of hot melt adhesive powder is the key to product quality, but the easy hygroscopicity of hot melt adhesive powder makes it difficult to spread evenly, and the amount of distribution is not good Control; the melting temperature of hot melt adhesive powder is higher, and the melting temperature of breathable film is lower. The hot melt adhesive powder cannot be completely melted during compounding, resulting in insufficient peel strength and poor surface flatness of the compound film. 4. Hot melt adhesive breathable coating compound: Features: faster production speed, low breathable loss rate of breathable film material (between 20-30%). Disadvantages: equipment investment is large (a set of 1600mm effective width hot melt adhesive breathable coating composite hot melt adhesive system costs more than 400,000 US dollars); the gluing weight is high (at an angle of 180 о, strength 3.0N/inch composite requirements For example, the amount of glue used can reach 4gsm or more); the coating head needs to be in contact with the coating material during coating, which requires high stability and flatness of the winding and unwinding equipment; the coating process exerts relatively high tension on the material However, non-woven fabrics and films are required to run under low tension, otherwise it is easy to cause stretching and deformation of the material, and the product will wrinkle after compounding, which will affect the quality of the product.