Pigment is the main component of ink, is a fine powder-like solid colored substance, can show ball, flake and other irregular shape. Generally, the diameter of pigment particles is in the range of several hundred nanometers to tens of microns (10-7~10-5m). The pigment can be evenly dispersed in the medium, but it is insoluble in the medium and does not react with the medium. Pigment is a colored body, it gives the ink color, at the same time, its dispersion, aggregation and directly affect the fluidity of the ink, chemical stability and dryness. Ink factory pigment selection error or improper use of ink, will cause a lot of quality problems, pigment caused by quality problems, do the following analysis, for the reference of peers. First, classification of pigments Pigments can be divided into inorganic pigments and organic pigments according to the characteristics of compounds. In organic pigments, they can be divided into lake pigments, color pigments and pigment dyes according to different molecular aggregation states. According to the different molecular structure, it can be divided into azo pigments and phthalocyanine pigments. According to the color characteristics, it can be divided into color pigments (such as yellow, magenta, green, etc.) and achromatic pigments (such as black, white, gray). Quality problems caused by pigment problems 1. Knife line problems caused by pigments 1)The pigment of the ink itself is badly ground, resulting in hard particles. (General ink fineness requirements ≤15μm). 2)When the ink is used for a long time, the resin wrapped in the pigment is missing, and the coarse particles produced by the pigment particles are clumped, condensed, and returned. In addition, the ink factory uses a carrier of color lake pigments, such pigments are soluble dyes precipitated with a precipitant, and then dyed on the high dispersion of aluminum hydroxide, barium sulfate, aluminum barium white and other carriers. This kind of ink will be used for a long time will wash away the dye, carrier separation, carrier clumping. Solution 1)Turn upside down and shake the new ink before opening the bucket. 2)The new and old ink is filtered with more than 100 mesh filters before entering the ink plate. 3)The ink that has been used for a long time is found to have floating pigments on the surface of the ink plate, indicating that the resin is not enough, and the ink mixing oil should be added for sufficient mixing and dispersion. It is best to mix the old ink with a dispersion mixer, and the printing plant can prepare a simple dispersion mixer. 2.Pigment caused by poor ink temperature resistance, high temperature cooking or bag hot press after discoloration Cause analysis The ink factory used the wrong pigment, the use of non-temperature resistant pigment. The printing factory used the wrong ink, and the ink that did not withstand temperature was used on the products of high temperature cooking bags. Solution When purchasing ink, we should check t...

Paper aluminum-plastic composite film in the actual application of medical packaging powder, granule packaging products compared to the plastic aluminum-plastic packaging commonly used in the market now has the following advantages: (1)The mechanical strength of the paper is high, the rigidity is good, and the ability to maintain the bag after forming is strong, which improves the cleanliness of the product appearance; (2)Automatic packaging does not need to be easy to tear, with good easy to tear effect; (3)Due to the high mechanical strength of the paper, when filling and sealing on the automatic packaging machine, it has a good resistance to the shear external force damage when sealing, and protects the aluminum foil from thermal sealing compression and compression break, which further ensures that the barrier performance of the middle layer aluminum foil is guaranteed. In front of the market, the main application of paper aluminum-plastic structure of drug packaging with composite film paper, aluminum, plastic, its main technical indicators are: 1.Appearance There shall be no perforation, foreign body, odor, adhesion, separation between composite layers and obvious damage, bubbles, wrinkles, dirt and other defects. The heat sealing part of the composite bag should be smooth and without virtual sealing. 2.Water vapor transmission The test temperature was 38℃±0.6℃, the relative humidity was 90%±2%, and the water vapor transmission was less than 1.5g/ (m²·24h). 3.Oxygen transmission The heat surface is towards the oxygen low pressure side, and the test temperature is 23℃±2℃, and the oxygen permeability is ≤3.0cm³/ (m²·24h·0.1MPa). 4.Peeling strength of inner layer and sub-inner layer: ≥ 2.5N / 15mm 5.Heat sealing strength: ≥ 12N / 15mm 6.Residual solvent The total amount of residual solvent shall not exceed 5.0mg/m², of which the residual benzene solvent shall not be detected, and the detection limit of a single benzene solvent is 0.01mg/m². First, roughness test of printing surface On the packaging of finished products, will be printed with a clear pattern and logo. However, we will also find that the printing on some materials (especially paper or paper film) packaging is fuzzy, some is related to the quality of the ink, the color process, but a large part is related to the roughness of the printing surface. Since the general printing ink layer is only tens of microns thick, if the printing surface roughness is too large, then the printed ink layer will be embedded into the deep layer of the material, so that the ink layer thickness on the surface is not uniform, which will produce the phenomenon of paste and white. We should be printed surface roughness test, by simulating the conditions of the printing press to measure the surface roughness, from the microscopic point of view to examine the smoothness of the material on the printability, according to the results of the roughness, according to 2 to 2.5 times to adjust the thickness of the ink...

①The residual ink is converted into gray black ink According to the principle of color science, the complementary color of the ink mixed together, its hue will become gray black (red + green, yellow + blue-purple). Therefore, we can use this principle to deploy the complementary ink into gray-black ink by deploying the special color ink, and add it to the black ink in a certain proportion to use it as black ink. In the operation, it is necessary to note that even the remaining oil belongs to the deployment of spot color ink, so there will be a certain color bias, and at this time, the complementary color of the biased color should be added according to the color bias. This method is not suitable for the conversion of light-colored ink, and should consider the composition of the ink, in accordance with the principle of similar mixing reasonable use. ②The residual ink is converted into a similar color ink The color of the ink can be divided into gray, black, white, magenta, red, yellow, green, blue, blue, purple, etc., and other colors can be changed from these basic colors. Therefore, even if there are thousands of products, countless colors, can be classified according to the basic hue. Moreover, there are many similar colors in many colors, and even the color is basically the same. Water-soluble and solvent-based inks, in particular, are more suitable for this method because of their convenient mixing and easy filtration. ③Conversion according to ink formula First of all, we must unify the form of ink formula, preferably in percentage form. Because the percentage formula is used, it is more helpful to compare the formulations, so as to find the correlation of ink color, and can easily identify the degree of color deviation between different formulations of ink to determine whether it can be converted to each other. Using this method, we need to do a good job of sorting, classifying and archiving the formula, so that it is more convenient to find the ink formula of similar hue in use ④According to the ink color card conversion This scheme is generally used for the conversion of ink with unknown ink formula, and the ink color card can be made by scraping or printing in order to analyze the composition of the ink. It can also find similar colors of ink according to the color of the ink color card, so that the remaining ink is converted into the corresponding color of ink according to the allocation method of the special color ink. The method of using residual ink conversion seems easy, but it requires the operator to have rich knowledge of color science and use it flexibly. Printing houses should usually pay attention to the establishment of ink formula, color cards and corresponding identification files, so as to quickly and accurately use the remaining ink, thereby reducing ink loss, reducing waste, and saving costs. Sinograce Chemical has the production of a variety of ink water-based resin, welcome to consult.

Waterborne Polyurethane (WPU) is a polyurethane system using water as a solvent or dispersion medium. In recent years, with the increasingly strict environmental regulations and the improvement of people's environmental awareness, waterborne polyurethane, as an environmentally friendly material, has received extensive attention and research. First, the characteristics of waterborne polyurethane Environmental protection: Water-based polyurethane uses water as a solvent and does not contain organic solvents, thus reducing the emission of volatile organic compounds (VOC) and meeting environmental protection requirements. Weather resistance: Waterborne polyurethane has good weather resistance and can maintain stable performance under different climatic conditions. Flexibility: Waterborne polyurethane coating has good flexibility, can resist external stress, reduce cracking and peeling phenomenon. Wear resistance: Waterborne polyurethane coatings have high wear resistance and are suitable for applications where frequent friction and contact are required. Chemical resistance: Waterborne polyurethane has good resistance to a variety of chemicals, such as acids, alkalis, oils and so on. Second, the synthesis method of waterborne polyurethane The synthesis of waterborne polyurethane mainly includes the steps of prepolymerization, chain extension, neutralization and emulsification. Firstly, the prepolymer is formed by prepolymerization of polyol, isocyanate and other raw materials. Then, the molecular weight of polyurethane was increased by chain extension reaction with chain extender. Then, the polyurethane was neutralized by neutralizing agent to obtain hydrophilicity. Finally, the polyurethane is dispersed in water by emulsification to form a stable water-based polyurethane emulsion. Third, the application field of water-based polyurethane Paints and coatings: Waterborne polyurethane, as an environmentally friendly coating, is widely used in construction, furniture, automobiles and other fields. Its excellent weather resistance, flexibility and wear resistance make it an ideal coating material. Adhesive: Waterborne polyurethane adhesive has excellent bonding properties and water resistance, and is widely used in bonding wood, leather, fabric and other materials. Textile additives: Waterborne polyurethane can be used as textile additives to improve the softness, wrinkle resistance and wear resistance of textiles. Medical field: Because of its good biocompatibility and hydrolysis resistance, waterborne polyurethane is also widely used in the medical field, such as the preparation of artificial skin and drug carriers. Other fields: Water based polyurethane can also be used in ink, leather finishing agent, fiber treatment agent and other fields.