• Overview of waterborne polyurethane coating
    Overview of waterborne polyurethane coating

    2022-01-06

    According to the current development trend of waterborne polyurethane coating, green polyurethane coating technology is mainly divided into two categories: waterborne polyurethane coating and solvent-free polyurethane coating.Among them, solvent-free polyurethane coating mainly contains polyurethane hot melt adhesive coating and light curing polyurethane coating.Waterborne polyurethane (WPU) is a polyurethane system with water as the dispersion medium instead of organic solvent. Compared with the traditional solvent-based polyurethane coating agent, it is environmentally friendly and more safe and reliable in logistics, transportation, production and manufacturing. The actual physical and chemical properties are shown in the figure below. Comparison of waterborne polyurethane and solvent-based polyurethane property Water based polyurethane Solvent-based polyurethane viscosity It is affected by the interparticle force of emulsion particle size It is affected by relative molecular weight, solid content, solvent, etc film-processing ability Film-forming slowly Easy to film toxicity The relative environmental protection Organic solvents are volatile and have a toxic smell solvent resistance Poor water resistance Poor resistance to toluene butanone Difference in solvent polyurethane film link of waterborne polyurethane in the film, the emulsion in water at high temperature evaporation concentration gradually, latex particle formation sedimentary gradually, until the interface disappeared and mutual fusion between latex particles, the final latex particle in thread shaped polyurethane chain close to each other mutual diffusion chain end, the last film, as the chart shows. Difference in solvent polyurethane film link of waterborne polyurethane in the film, the emulsion in water at high temperature evaporation concentration gradually, latex particle formation sedimentary gradually, until the interface disappeared and mutual fusion between latex particles, the final latex particle in thread shaped polyurethane chain close to each other mutual diffusion chain end, the last film, as the chart shows. The stability of waterborne polyurethane emulsion is an important standard in the production, processing and application of products. In order to obtain better emulsion stability, waterborne polyurethane emulsion is generally prepared by self-emulsification method.According to the introduction of hydrophilic groups in polyurethane molecular chain, stable emulsions can be formed without adding emulsifiers, which can obviously improve the phenomenon of large particle size and multiple dispersion of emulsion and the residue and migration of small molecule emulsifiers commonly existing in external emulsification method.However, the widespread existence of hydrophilic groups in the polyurethane chain segment is easy to reduce the color fastness to water and wet friction of waterborne polyurethane coating products.In order to improve the shortcomings of the self-...

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  • Basic principle and definition of antifogging coating
    Basic principle and definition of antifogging coating

    2022-01-05

    Antifogging paint is a very practical paint, it can prevent fog, block people's sight, the basic principle and definition of antifogging paint what, let us know about it. Antifogging coating is a kind of functional coating.It is based on the hydrophilic group or hydrophobic group as the main component of polymer materials, and other additives and organic solvents in proportion to prepare, with anti-fogging function of chemical products. Because solidify method is different, have heat solidify to prevent fog coating and UV(ultraviolet) light solidify to prevent fog coating ultraviolet solidify to prevent fog coating to have higher transmittance than heat solidify to prevent fog coating normally.Uv-curable antifogging coatings usually have higher light transmittance than heat-curable antifogging coatings.Because they have different antifogging mechanisms, they also have hydrophilic antifogging coating and hydrophobic antifogging coating hydrophobic antifogging coating is more widely used than hydrophobic antifogging coating. Whether it is heat curing anti-fogging coating or uv curing anti-fogging coating, there are only two types of anti-fogging mechanism: hydrophilic anti-fogging and hydrophobic anti-fogging. Hydrophilic antifogging and hydrophobic antifogging are two different processes of water molecules, so their antifogging mechanisms are completely different: hydrophilic antifogging coatings make surfaces hydrophilic and reused. Anti-fog coating hydrophilic groups of hydrophilic adsorption moisture factor, reduce the surface tension of water, reduce water molecules and the contact Angle between the surface and the water vapor is not on surfaces accumulate into small water droplets, will be wet, spread or forming a thin transparent film adsorption on the surface, no longer scattering incident light, does not interfere with the line of sight of people, so as to achieve the purpose to prevent mist. SINOGACE CHEMICAL produces nano antifogging coating, is nano super hydrophobic series products, welcome to consult

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  • Printing glue requirements
    Printing glue requirements

    2021-12-29

    Printing mucilage requirements The requirements of printing mucilage for manual plate printing Manual table printing is to press the screen on the fabric of the table for manual scraping, and the pressure extrusion on the scraper will print the glue through the mesh hole of the pattern part to the fabric. The shear stress of the binder is small, so thePrinting mucilageis required to have good rheological and mesh permeability, that is, the viscosity decreases when the scraper is scraped, and the mesh is transferred to the fabric, and permeated to the fabric interior; When the scratch printing stops, the shear stress disappears, and its viscosity can quickly return to the original level, to ensure that the pattern printed on the fabric is clear, so the printing paste used for manual platform printing should have a certain thickness, that is, a higher viscosity, but the rheology is better, the lag thixotropy is small. The requirements should be paid attention to during the scraping operation Drawing printing pulp is a kind ofPrinting mucilagepulp material, is a kind of milky thick pulp, mainly used for drawing printing process printing, its flow performance is very good, not plug net, quality is stable, the use of process is very simple. Printing pulp in scratch printing operation should pay attention to the method and requirements: mesh between 800-1200 mesh; Drawing printing powder to add 5%-10%, to stir to decompose completely; Before starting printing, the pulping glue should be filtered. If it is found to be thick in the production process, it is necessary to stop using it.Press, printing parts to be dry to press, in order to avoid color. If the flower appeared white edge, then it is necessary to pressure that overheating; Heat treatment after printing, bake for 3 minutes or press for 15-2 seconds between 150-170℃; When scraping printing, scraping 4 knives at a time.  Printing mucilage and substrate matching requirements Printing manufacturers in the process of printing production, often encounterPrinting mucilageand cloth adhesion problem.The main reasons for this situation are as follows: the surface of printed cloth (cut piece) is covered with water-repellent coating grease material and other substances, resulting in insufficient adhesion betweenPrinting mucilageand printed cloth; The adhesion ofPrinting mucilageitself is not enough, resulting in poor adhesion; Improper operation of printing process will also cause poor adhesion, such as insufficient printing strength, less pulp or no appropriate drying method,Printing mucilageis not completely solidified. Therefore, before printing factory production, it is necessary to choose good Printing mucilage and substrate matching, and make samples, and then production, to ensure the quality of production products.

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