Organic pigment is the most basic material to provide color to the ink, but as the ink attached to the surface of the substrate, the color shown to the consumer often produces more or less deviations from the color of the pigment itself. The reason is that in the ink, the pigment particles do not exist alone, but are dispersed in the connecting material medium. Microcosmic, the best wetting dispersion state of a pigment particle is completely evenly wrapped in a resin binder and attached to the surface of the substrate.The display of color is that the light incident on the coated pigment surface through the resin bonding material film layer is transmitted to the consumer through reflection. The transparency of the resin is good and bad, and the size of the color number directly affects the expression of different colors. At the same time, whether the resin is sufficient for the wetting and dispersion of the pigment directly affects the uniform coating of the resin on the pigment, and also affects the color of the ink itself. Sinograce Chemical produces primer adhesion promoter and ink resins for PP and PE.Chemical Additives.welcome to consult.

Ink resin is the pigment carrier in the ink, is the core material of the ink, its quality is good or bad, will directly affect the performance of the ink, because the connection material to a large extent determines the viscosity of the ink, viscosity, dryness, fluidity and other properties. Color fastness The adhesion between the ink and the substrate mainly includes the chemical bond force (that is, the interatomic force), the intermolecular force (hydrogen bond force and van der Waals force), the interface electrostatic attraction and the mechanical force.The main source of these forces is the action between the ink resin binder and the substrate.In general, for PE, PP and other non-polar substrates, even if the corona surface treatment, the surface tension can only reach about 38 dyne, should be used resin structure for non-polar such as chlorinated polypropylene resin connection material; For surface polar substrates such as PET and PA, polyurethane resin bonding materials can be used.Polyurethane ink bonding material system can often solve the adhesion problem on the non-polar substrate by adding a small amount of adhesion enhancer specially used for PP and PE, or using a small amount of chlorinated polypropylene resin with polyurethane resin, and has been able to achieve the universality of a resin bonding material. At the same time, it solves the problem of toluene solvent residue which is easy to occur with chlorinated polypropylene resin as the connection material, which is particularly important in the 21st century when promoting green environmental protection. It can be seen that the resin bonding material in the ink as a dispersion wetting medium also provides the most basic and most important adhesion fastness between the ink and the substrate, which is one of the most basic indicators of the ink. Sinograce Chemical produces primer adhesion promoter and ink resins for PP and PE.welcome to consult

How to choose additives in waterborne polyurethane? There are many kinds of water-based polyurethane auxiliaries, and the application range is wide, but the methods of auxiliaries are correspondingly regular. The compatibility of additives and products is also the first factor to be considered in the selection of additives. Under normal circumstances, the auxiliary and the material are required to be compatible (similar in structure) and stable (no new substance generation) in the material, otherwise it is difficult to play the role of the auxiliary. The additive in the additive material must maintain the original performance of the additive for a long time without changing, and the additive in the application environment, the ability to maintain the original performance is called the durability of the additive. There are three ways for auxiliaries to lose their original properties: volatilization (molecular weight), extraction (solubility of different media), and migration (solubility of different polymers). At the same time, the additive should have water resistance, oil resistance and solvent resistance. In the processing process of materials, additives can not change the original performance and will not have a corrosive effect on the production and processing of machines and construction supplies. The additive needs to meet the special requirements of the material in the use process, especially the toxicity of the additive. In order to get better results, the application of additives is mostly mixed. When choosing a combination, there are two situations: one is the combination application to obtain good results, and the other is for a variety of purposes, such as not only leveling but also defoaming, not only to add light but also antistatic. This is to consider: in the same material will produce synergies between the additives (total effect is greater than the sum of the effect of single use), the addition effect (total effect is equal to the sum of the effect of single use) and the antagonistic effect (total effect is less than the sum of the effect of single use), so the best time to produce synergies, to avoid the antagonistic effect. In the production process of water-based polyurethane to add a certain type of additives, it is necessary to pay attention to its role in the various stages of storage, construction, application, and consider and evaluate its role and impact in the next section. For example, when the water-based polyurethane paint is operated with wetting and dispersing agents, it plays a certain role in storage and construction, and it is also good for the color of the paint film. There is usually a dominant effect, and at the same time cause a series of simultaneous positive effects, such as the use of silicon dioxide, there is a extinction effect, and the absorption of water, surface anti-adhesion and other positive effects. In addition, in the use of a certain agent may have a negative effect, such as the addition of si...

There are four common waterborne polyurethane thickeners: ①Inorganic thickeners, such as flake silicates, fumed silica, etc.; ②Natural organic thickeners, such as cellulose ethers; ③Synthetic organic thickeners, such as polyacrylates, polyvinylpyrrolidone; ④associative thickener. This paper mainly introduces the associated emulsion thickener. Associative emulsion thickeners are non-ionic synthetic water-soluble polymers, alkali-soluble emulsions and other thickeners with hydrophobic groups. Hydrophobic groups are generally composed of alkyl groups with a carbon atom number of 12 to 22. In view of the association between hydrophobic groups to form a network and thicken, they are called associated thickeners. By adjusting the relative molecular mass of the hydrophobic group or the polymer main chain to thicke, from the inclined flow to the pseudoplastic flow transformation, from the properties of some polymer surfactants found that this has a strong thickening, such rheological characteristics can be freely designed. The advantages of association thickeners used in waterborne polyurethanes are: ①High thickening effect; ②The flow is closer to the cow inclination fluid; ③The viscosity of low shear rate is relatively low, and the flattening property is good; ④The viscosity of high shear rate is better and the film forming property is good; ⑤It is not easy to form a spatter effect ⑥It will not be degraded by microorganisms. The disadvantage is that the thickening effect is more sensitive to the formulation of water-based coatings, including the size of latex particles, emulsifiers, additives, and cosolvent types. The association type thickener has been successfully applied in waterborne polyurethane system for several years, and there are industrial products in China. This association type thickener is dissolved in water/organic solvent (such as propylene glycol) to form polymer solution. Among them, the role of organic solvents is to reduce the viscosity of concentrated solutions and improve operability. However, organic solvents also become part of the VOC in the paint. The new development direction is to make the association thickener solvent-free. The role of the solvent is replaced by a polymeric surfactant that acts as a solubilizer for polymers in water.