Common Problems of PVC Bags

May 16,2022

Today, we’ll talk about the common problems of PVC bags and comparison between PVC bags and EVA bags in production.


pvc  bag


What are the common problems with PVC bags?


The material problems of PVC bags mainly include three aspects: thickness, color, and appearance.


Thickness problem: if the handle feels thin, it is mainly because the oil content of PVC material is increased when the bag is made; Also, it is related to the temperature. In summer, when the temperature is high, the feel will be soft and thin.


Color problem: the transparency of PVC bags can be divided into general transparency and super transparency. The color film changes the color of the bag by adding pigment to the production process. If the proportion is different, the adjusted color will also have a certain error.


Appearance problem: PVC bags with a strong smell contain a large amount of PVC in their material composition, which has a certain smell. PVC materials generally have a smell, which will be toxic under high temperatures.


PVC bags in printing are mainly the problem of leakage points, screen printing chromaticity, and screen printing color difference.


This kind of bag is generally silk screen printing. If the printing time is long, the ink is easy to dry, which will block the screen, and there will be leakage points. In addition, if there are dirty things in the printing process, there will be a few leakage points. Due to its manual positioning, it is not easy to control the accuracy of the position. Generally, there will be a chromatic error, which is a reasonable situation. As for the color difference of silk screen printing, because the color is adjusted manually every time, it will be different every time.


Process: the white position of bag hot pressing is mainly caused by too many times of use of a copper frame and too high temperature; The bag edge pressing is not smooth enough because the copper frame temperature is not adjusted well during hot pressing, and the temperature is low and not pressed through; The buttons are not smooth enough, and the air holes are not smooth enough.


Comparison between PVC bag and EVA bag in production


PVC bags and EVA bags are also plastic bags, but due to different materials, it is easy to produce different problems in the production process. We need to choose different production methods according to different materials to make the best plastic bags.


PVC material is a kind of plastic material with more plastic bags. The material is relatively soft, the voltage, temperature, and strength are easy to adjust, and the most suitable packaging can be made according to the customer's requirements. During the production process, PVC bags are easier to paste through high-frequency voltage and are not easy to break, but the softness is easy to change due to weather, so they are not suitable for use in some special environments.


EVA material is one of the high-grade plastic materials. It is usually used to make more plastic bags, but there are many problems in the process of making EVA bags, so there are many details to deal with. For example, in high cycle voltage, if the temperature or pressure is not enough, the EVA bags will be easy to crack, resulting in problems in the plastic bags. Because these problems need to be paid special attention to in the process of making, to make the best plastic bags.


Although PVC bags and EVA bags are plastic bags, we need to pay attention to these problems in production to make the best plastic bags.


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