The main reason why PVC has these two advantages is its production process. The production process of PVC bags is not complicated. The general production line is generally composed of a roller press, a printing press, a back coating machine and a cutting machine. The thin film is consumed together and the pattern is printed on the front side of the film by a printing machine, and a layer of back coating is attached to the discrepancy of the film by a back coater.
This layer of back coating seems to be a very small step, but it is definitely very important and indispensable. It is an important guarantee for the function of the PVC bag.
The back coating is composed of special materials and is a kind of high-energy affinity agent. It is precisely because of this back coating that the PVC film can be tightly integrated with the MDF or other boards, and it is talented to insist on long-term non-opening. The problem with the general mask is that it can’t deal with the withering problem of the film.
The PVC packaging bag is made of frosted PVC materials, which is beautiful and durable, easy to use, soft to the touch, and affordable. It is made of high transparent PVC, special anti-static materials, the bag is non-adhesive, easy to use, fine workmanship, no corners The burrs do not hurt your hands, the zipper is used smoothly and has a long life, and the sealing is tightly pressed and not easily broken. It is a selection of promotional packaging for all kinds of underwear, socks, documents, cosmetics, household goods, home textiles and so on.
Food quality includes the color, flavor, nutritional value, shape, weight, and hygienic indicators of the food. Almost all processed foods need to be packaged before they can be sold as commodities. Although food is a commodity whose quality is most susceptible to deterioration due to environmental factors, each packaged food must meet the corresponding quality index of food packaging bags within the set shelf life.
The entire circulation link of food from raw material processing to consumption is complex and changeable. It will be affected by biological and chemical infestation, as well as various environmental factors such as light, oxygen, moisture, temperature, and microorganisms that appear during the production and circulation process. Impact.
The effect of light on food quality
(1) The spoilage effect of light on food
Light has a great influence on the quality of food. It can trigger and accelerate the decomposition of nutrients in food, and the spoilage reaction of food occurs. It is mainly manifested in four aspects: promote the oxidation reaction of oil in food and cause oxidative rancidity; make food The pigments in the product undergo chemical changes and discolor; make the green, yellow, red in plant foods and red in meat foods dark or brown; cause the destruction of light-sensitive vitamins such as B vitamins and vitamins, and combine with other substances Undesirable chemical changes occur; causing denaturation of protein and amino acids in food.
(2) The law of light penetration into food
Light can promote the inside of food-the series of changes are due to its high energy. Under the light, the light-sensitive components in the food can quickly absorb and convert the light energy, thereby stimulating the chemical reaction that occurs inside the food. The more the food absorbs light energy and the deeper the transfer, the faster and more serious the food will deteriorate. The amount of light energy absorbed by food is expressed by optical density. The higher the optical density, the greater the light energy, and the stronger the effect on food deterioration.
Post time: Aug-04-2021