• The importance of residual ink treatment in the printing industry
    The importance of residual ink treatment in the printing industry


    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.

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  • Waterborne polyurethanes: properties, synthesis and application areas
    Waterborne polyurethanes: properties, synthesis and application areas


    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.

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  • Adhesion strength characteristics of waterborne polyurethane emulsion
    Adhesion strength characteristics of waterborne polyurethane emulsion


    Water based polyurethane emulsion has soft properties, so that it has good adhesion when attached to the surface of the object; At the same time, it can maintain a certain strength and does not crack. It is especially suitable for articles in high temperature, humid and chemically corrosive environment. This substance also has superior wear resistance and film smoothness, so it can form a uniform and tight film on the surface of metal, plastic, etc., and further enhance the surface adhesion of treated PE, OPP film, TPU, PU leather and other materials to ensure long-term protection and maintenance of objects

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  • What are the factors affecting the viscosity of waterborne polyurethane emulsion
    What are the factors affecting the viscosity of waterborne polyurethane emulsion


    The viscosity of waterborne polyurethane emulsion has different distribution range, and the viscosity of waterborne polyurethane emulsion has different requirements when applied in different fields. In addition to adjusting the viscosity by adding thickening agents, it can also affect the viscosity of waterborne polyurethane emulsion from the molecular structure, including the content of hydrophilic groups, the solid content of waterborne polyurethane emulsion, and the degree of neutralization. The content of hydrophilic groups on the structure of waterborne polyurethane affects the size of emulsion particles and its viscosity. In anionic waterborne polyurethane, when the carboxylic acid hydrophilic groups increase, the size of the colloidal particles decreases, the distribution Narrows, and the viscosity of the emulsion increases, because the force between the colloidal particles and water increases. The viscosity of polyurethane emulsion is related to the hydrophilicity of hydrophilic monomer, particle size and size distribution, and particle density in polyurethane emulsion. The influence of solid content on the viscosity and particle size of waterborne polyurethane is also obvious. When the solid content of waterborne polyurethane is low, the content of hydrophilic monomer is fixed, and when the solid content increases, the number of particles in the emulsion also increases, and the force between the latex particles and water increases, so the viscosity of the emulsion increases. When the solid content of waterborne polyurethane emulsion is too large, the prepolymer is difficult to disperse in water, the size of latex particles becomes larger, the distribution becomes wider, and the viscosity of emulsion becomes smaller. The degree of neutralization also affects the viscosity of aqueous polyurethane emulsion. During the preparation of waterborne polyurethane, due to the double action of hydrophilic group and neutralizer, the double electric layer effect affects the viscosity change. As the neutralization increases, the viscosity may increase more, so the neutralization should be strictly controlled when preparing waterborne polyurethanes.

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