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Low-carbon environmental protection is the rigid demand of the industry and government administration in recent years.
Light anti-corrosion industrial paint also needs energy saving and emission reduction in the big environment.
The improvement of water-based resin and supporting products, and the implementation of policies and regulations, water-based paint has become an important development direction.
.
In the process of "oil-water" conversion, reducing VOC becomes the best choice
.
The use of solvents in water-based coatings has put forward new requirements for thickening and anti-settling of water-based coatings .
Coatings Online Coatingol.
com
.
In water-based industrial coatings, the presence of solvents has a great impact on the anti-settling performance of the system.
Longhai Chemical has conducted a series of experiments in water-based epoxy and water-based alkyd systems, and then I will share with you
Comparison in waterborne epoxy systems
Basic formula:
1.
1 Comparison of different thickening systems
In this system, the polyamide thixotropic agent can effectively improve the anti-sag performance of the system.
Compared with the polyurethane thickener, there is no post-thickening phenomenon, and the system has good storage stability
.
At the same time, it provides a good anti-settling effect
.
Polyurethane type thickeners provide good sag resistance, but their own hydrophilic properties lead to poor salt spray resistance in the later stage of the paint film, while polyamide additives have no negative effect on the salt spray resistance of the system.
influence
Polyamide type thickeners provide good sag resistance to waterborne epoxy systems without compromising the film's salt spray resistance
.
2.
Comparative application in waterborne alkyd systems
Basic formula:
2.
1 Comparison of different thickening systems
We compared different anti-sag additives such as polyamide, polyurethane, and fumed silicone.
The comparison effect is shown in the figure below.
The polyurethane system has low thickening efficiency and cannot effectively provide anti-sagging performance, while the large-scale use of fumed silica leads to foam stabilization and difficulty in defoaming the system
.
2.
2 Solving the problem of water separation
In view of the characteristics of water-based alkyd that is easy to separate water, in addition to the necessary PH adjustment of the system, polyamide type anti-settling agent has a more significant role in this type of system.
Compared with competing products or polyurethane thickeners, 7802 shows Good waterproof performance
.
Compared with polyurethane-type thickeners, polyamide-type thixotropic agents can form hydrogen bonds between polyamide molecules in addition to their own binding to latex particles, thereby forming a network structure to achieve the purpose of stabilizing the system.
The introduction of the solvent will further swell it, without the adsorption of the latex particles being captured by the solvent molecules like the polyurethane thickener, resulting in the difficulty of thickening and the problem of poor sag resistance
Through the above comparison, polyamide rheological agents provide a superior anti-sag and anti-settling effect in different water-based systems, but in practical applications, resin systems vary widely, and Longhai Chemical still recommends a variety of Mixing agents to obtain sag resistance, storage stability, and good workability of the product system
.
