With the rise of the water-based market, compared with water-based acrylic systems, water-based 2K epoxy, water-based alkyd, epoxy ester, water-soluble acrylic, and water-based polyurethane systems, due to differences in material types and formulation designs, lead to the failure of these systems. There are many problems in thickening, anti-sagging, anti-sinking and anti-water separation. Probably because of the complexity and diversity of multiple raw materials in water-based formulation systems.
Water-soluble alkyd, epoxy ester, acrylic system, and water-soluble amino baking paint, these systems based on water-soluble system, in addition to water, there are a large number of co-solvents in the system, the content of these solvents is in the resin component. When added to the formula, the proportion of solvent components is also 5-15%. Formulators will also add some additional co-solvents according to construction and other considerations. A large number of co-solvents and different types of co-solvents have a huge and differentiated impact on the thickening and anti-sagging of the system. Thickness can not be solved well, and it will inevitably cause problems of sedimentation and water separation.
For waterborne epoxy systems, for epoxy emulsions with internal emulsification (reactive grafting), traditional associative thickeners are at a loss when faced with such emulsions, because traditional associative thickeners are at a loss. The association point of the thickener has no association effect for most epoxy emulsions, or is very weak, and the epoxy emulsion itself or the formulation design of water-based epoxy will also bring a part of the solvent system, such as PM, these More or less, it will affect the thickening and anti-sagging effect of the entire system.
The anti-sagging and anti-sagging performance is better, and a three-dimensional network structure must be established in the system to hold the powder and resin, and this three-dimensional network structure must be easily deconstructed in the presence of shearing force, and can be quickly recovered after deconstruction. , this thixotropy can solve the problem of anti-sag very well.
The mainstream anti-settling and anti-sagging agents on the market can be divided into 3 types:
1, Organic soils are sheet-like structures that attract each other by positive and negative charges to form a ‘card-house’ three-dimensional structure;
2, Fumed silica/polyurea, the three-dimensional network structure is established entirely by hydrogen bonds;
3, Vinyl wax pulp, polyamide wax pulp anti-sagging agents and hydrogenated castor oil, rely on wax components and solvents to expand together to form a gel structure, which makes pigment suspension and paint resistance to sag, and also relies on hydrogen bonds to establish some spatial network structures.
These three types of anti-settling and anti-sag agents have such a mechanism that alcohol ethers will quickly deconstruct their three-dimensional network structure and fail to build up. For organic soils, a small amount of alcohol in an appropriate amount will help activate the organic soil, which is conducive to the better establishment of a trapped structure. If the amount of alcohol exceeds this amount, the established three-dimensional trapezoidal structure will be quickly deconstructed, thereby losing anti-settling and anti-sagging effect.
Moreover, the above three types of additives are not realistic for initial viscosity building or rapid viscosity building after the shear force is removed, so we can experience that they have a good effect on the anti-settling and anti-water separation of the system. , but it is not helpful for the anti-sagging after the construction shear disappears (or it is not cost-effective, if you increase the dosage, it will also work, but the cost will also go up).
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