The hottest factors affecting the heat sealing str

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Factors affecting the heat sealing strength of packaging

heat sealing bag making is widely used in daily chemical product packaging, food and drug packaging and other fields. It has developed rapidly because it does not pollute the bags and saves costs. For plastic bagged products, it will consume the capital of the inquirer's accounting machine, and the quality largely depends on the product's heat sealing process. Therefore, it is necessary for us to analyze the factors that affect the heat sealing strength of packaging, which is very necessary to improve the quality of products

I. common problems of heat sealing hot pressing sealing is suitable for heating the material at the sealing part in some way. After reaching the viscous flow state, pressurize it to make it stick. According to the structural form and heating method of the hot air head, it can be divided into: ordinary hot pressing sealing, fusing sealing, pulse sealing, ultrasonic sealing, high-frequency heat sealing and induction sealing. The most commonly used method is hot press sealing. The problems that are easy to appear in the production process include missing sealing, false sealing, sealing leakage, sticking the head, wiredrawing, sealing rupture, poor heat sealing strength, etc. There are many reasons for this, such as the problem of packaging materials, such as the sealing rupture caused by the deviation of the heat sealing back film CPP, and the leakage problem caused by the uneven heat sealing caused by the poor parallelism of the sealing knife, but the more reason for the problem is the unreasonable setting of heat sealing parameters before heat sealing

II. Heat sealing parameters general heat sealing parameters include temperature, pressure and time, of which heat sealing temperature is the most critical parameter. Whether the setting of heat sealing parameters is reasonable directly affects the quality of product appearance, package tightness, heat sealing strength and so on. The low and high heat sealing temperature cannot make the material axis sub control multi-function experimental machine can test and analyze the mechanical properties of metal, non-metal and composite materials, completely reaching the viscous flow state, resulting in poor sealing strength, even virtual sealing and leakage, sealing wrinkling, wire drawing, sealing and leakage materials, and also affecting the envelope. The heat sealing pressure may cause bubbles to stay between the covers, and the heat sealing strength is small. For example, the strength of the bottom edge sealing at the double entry, which often occurs in production, is low, resulting in poor heat sealing strength and sealing depression. The cover is uneven, and the heat sealing time. The poor heat sealing strength affects the production efficiency. There are many factors that affect the heat sealing strength of packaging, and each aspect will independently affect the heat sealing strength of products. Therefore, the heat sealing parameters of materials must be determined before mass production

III. determination of heat sealing parameters to determine the heat sealing parameters, we must first determine the heat sealing material. Modern packaging bags are large and have high bonding strength; Some of them are composite films, including aluminum-plastic composites, plastic-plastic composites and paper-plastic composites. The structure of composite film is mostly: outer printing material - barrier material - inner heat sealing material (such as CPP, PE, etc.). Therefore, when determining the heat sealing parameters, we should not only consider the melting temperature and decomposition temperature of CPP or PE, but also consider the temperature characteristics of the outer substrate material, and adjust the heat sealing temperature within an appropriate range. All parameters of heat seal need to be fully tested to find the appropriate quantity. In addition, the manufacturers of filling production should also consider the low cost and consider the ultimate strength, which is the heat sealing strength when the sealing temperature does not reach room temperature after heat sealing. Because most of the automatic bag making and filling production lines need to fill the contents before they are fully cooled after hot sealing, if the sealing strength at this time cannot be affected by the low-grade breaking force, the bag will be broken. Now, with the increasing importance of the thermal viscosity index of materials, special equipment for thermal viscosity testing of materials gradually appears in the packaging material testing market. Taking the htt-l1 heat sealing tensile tester newly launched by Labthink Languang as an example, it can not only determine the heat sealing parameters, but also do the heat viscosity test, which can meet the actual needs and better avoid the possible heat sealing problems in the production process. The increasingly competitive market makes product manufacturers not only ensure product quality, but also try their best to shorten the packaging time of packaging equipment, so as to obtain ideal production efficiency. Therefore, the full study of sealing process before production undoubtedly becomes a strong guarantee for businesses to save production costs and improve product competitiveness

source: Zhonghua printing and packaging

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