The transparency of composite film is very high, but in the composite processing of plastic film, the composite film often has problems such as insufficient transparency. So, what is the reason for affecting the transparency of the composite film? This article analyzes one by one for reference. Improper selection of adhesives: Such as the color of the adhesive itself is dark or the fluidity is insufficient, the leveling performance is poor, and it cannot be fully spread on the composite base film. Generally, the higher the solid content of the main glue, the better the fluidity, which is conducive to spreading on the film. In general, 75% of the glue is better than 50% of the transparent effect, 50% of the glue is better than 40% or 35% of the glue. For compliant films with high transparency requirements, the use of 50% and 40% adhesive composite is difficult to meet the requirements. Process problems: First of all, the drying temperature of the drying channel of the composite machine is too high, and the solvent on the surface of the adhesive liquid is quickly dispersed (steam), and the adhesive liquid is crusts on the surface prematurely. Then, when the heat goes deep into the inside of the adhesive liquid layer, the solvent under the adhesive film will vaporize. When the gas breaks through the epidermal adhesive film to form a ring like a volcanic vent, which also makes the adhesive layer not transparent enough. Secondly, if the conforming roller or scraper is defective, a certain point is not compacted, forming a neutral, which will also cause the compliant film to be opaque. There is too much dust in the air added to the working environment, and there is also dust in the hot air sucked into the drying channel after gluing, which is stuck on the surface of the adhesive layer or sandwiched between the two layers of the base film when composite, and a lot of dust causes opacity or poor transparency. The solution is to close the glue part of the composite machine, and use a high mesh filter on the air inlet of the baking channel to block the suction of dust (that is, the dust in the hot air of the baking channel). In addition, if there is no roll or the roll is not clean, it will make the composite film not transparent enough, or the amount of composite glue is insufficient, the glue is uneven and there is a blank, and there are small bubbles, resulting in speckles or opacity. The solution is to check and adjust the amount of glue so that it is sufficient and evenly coated, resulting in the common name of "pockmarked face film". Other problems It should be noted that the composite hot drum temperature is not enough, the hot melt part of the glue fails to melt, the cooling roller temperature is too high, and the failure to cool suddenly can cause poor transparency of the compliant film. Solution: The temperature of the hot drum shall not be lower than 70 degrees, and the hot melt part of the colloid begins to melt when the temperature reaches 65 ...

The performance requirements of water-based varnish for printing paper glazing are as follows: 1.The film has good environmental resistance. Some of the printed matter after glazing is used to make all kinds of packaging cartons, in order to be able to play a good protective effect on the packaged products, the environmental resistance of the glazing film layer must be better. For example, the packaging of food, cigarettes, cosmetics, clothing and other goods must have moisture-proof and mildew proof performance. After drying, the chemical resistance of the film layer should be stable, and its properties can not be changed by contact with chemical substances such as weak acids or weak bases in the environment 2.High transparency of the film layer, no discoloration. Prints to obtain excellent glazing effect, depends on the surface of the printed sheet to form a colorless transparent film, and after drying the text does not change color. It should not be discolored or yellowed due to sun exposure or long use time. 3.The film layer has a certain wear resistance. Printed paper requires a certain wear resistance and scratch resistance after glazing. 4.Good leveling, smooth film surface. There are many kinds of printing materials to print the impact of graphics, surface absorption, smoothness, wettability and so on are very different, in order to make the coating on the surface of different products can form a smooth film layer, requiring water-based polish smooth, smooth film surface. 5.With a certain flexibility. The bright film formed by any kind of water-based gloss oil on the surface of the printed matter must maintain good elasticity to adapt to the flexibility of paper or cardboard, and will not be damaged or cracked and fall off. 6. It has a certain adhesive force on the surface of printed matter. Due to the influence of the integral density of the ink layer on the surface of the printed matter, the surface adhesive suitability is greatly reduced. In order to prevent the film layer from dry cracking and defilm in use after drying, it is required that the film layer has strong adhesive force, and has certain adhesive force for ink and various auxiliary materials used in ink mixing.

1.There are many formulations of coated glue, and different formulations need to be determined according to the specific use. It generally includes basic glue, thickener, curing agent, auxiliaries and other ingredients. 2.Basic glue is the most important component of laminating glue, it can be selected according to different use requirements of different types, such as water-based, oily, diluent and so on. Thickeners can increase the viscosity of the glue, making it more suitable for coating on the film. The curing agent can make the coating glue cure quickly and improve the firmness of the coating. The additives can improve the water resistance, heat resistance, weather resistance and other properties of the film coated glue. 3.For different coated glue requirements, you can combine references to different formulations to determine the most appropriate formula. At the same time, attention needs to be paid to ensure the quality and proportion of each ingredient to give full play to the role of each ingredient.

Color paste, also known as pigment paste, is an important form of dye application, which is widely used in textile, ink, paint and other industries. In the classification of pastes, low-halogen pastes and ordinary pastes are two common types. They have certain differences in composition, performance and use, and the differences between the two types of pastes will be discussed in detail below. First of all, from the composition point of view, the main difference between low halogen color paste and ordinary color paste is the content of halogen elements. Halides are elements of the oxygen group, including fluorine, chlorine, bromine and iodine. Low halogen pastes refer to a class of pastes with low halogen element content, while ordinary pastes do not have special restrictions on halogen elements. Low halogen pastes are usually formulated with dyes with lower halide content to meet the requirements of environmental friendliness and safety performance. In contrast, the content of halide elements in ordinary colorants may be higher, but it does not necessarily have a serious impact on the environment. Secondly, there are also obvious differences in performance between low-halogen pastes and ordinary pastes. Low halogen pastes usually have better light resistance, durability and wash resistance. This is because the dyes selected in the low-halogen pastes have a more stable chemical structure, which can maintain the bright and stable color during long-term use. The performance of ordinary pastes in these aspects may be relatively weak, and problems such as fading and fading may occur. In addition, the use of low halogen color paste and ordinary color paste is also different. Because of its better environmental performance, low-halogen pastes have been widely used in some fields with high environmental requirements. For example, in the textile industry, low-halogen pastes can be used for dyeing and printing, which can not only add rich colors to the fabric, but also meet the requirements of the environmental protection industry chain. In the coating industry, the use of low-halogen pastes can reduce the emission of harmful gases and protect the atmospheric environment. In contrast, ordinary pastes are widely used in areas with relatively low environmental requirements. In general, there are obvious differences between low-halogen pastes and ordinary pastes in composition, performance and use. Low-halogen pastes pay more attention to environmental friendliness and safety performance, with better light resistance, durability and washable performance, and are widely used in industries with high environmental requirements. The ordinary color paste is more used in the field of relatively low environmental requirements. With the improvement of people's awareness of environmental protection, the application prospects of low-halogen color paste will be broader and become an important development direction of the color paste industry. It is hoped that through t...