1. Liquid - Working Time
The working time, also referred to as the pot life or active time, is a critical phase in the curing process of epoxy resins. After mixing the resin with the hardener, the mixture remains in a liquid state, allowing for application, positioning, and adjustments. It's essential to complete all construction tasks within this period to ensure a strong and reliable bond. Once this window closes, the material starts to thicken and becomes less workable.
2. Gel - Curing Begins
During the gel stage, the mixture transitions into a semi-solid state, often described as "gelling" or "mutating." At this point, the epoxy no longer flows freely and begins to lose its viscosity. You can press it slightly with your thumb, and it will feel like a soft rubbery mass. While it's not fully cured yet, it's still chemically reactive, meaning that new epoxy can still bond to it, although the bonding strength is decreasing. This is the stage where you should avoid any interference or movement.
3. Solid - Final Curing
In the final curing stage, the epoxy becomes solid and can be sanded or shaped. At this point, it’s no longer possible to press it with your thumb, and the material has achieved about 90% of its full strength. You can now remove any clamps or fixtures and let it cure at room temperature. However, once fully cured, the surface becomes inert, so any new epoxy applied later must be properly prepared—such as by sanding—to achieve good mechanical adhesion.
Second, Polyisocyanate
Polyisocyanates are widely used as curing agents in various applications, including paints, foams, and coatings. Blocked water-dispersible polyisocyanates can be combined with melamine-based curing agents to reduce costs while improving performance. These types of curing agents are especially useful in two-component polyurethane coatings, which have become the standard in many industries such as automotive refinishing, industrial coatings, wood finishes, and plastic coatings.
As environmental concerns grow, there's increasing demand for high-performance curing agents that minimize volatile organic compound (VOC) emissions. Water-dispersible and low-viscosity options are becoming more popular due to their eco-friendly nature. Hybrid polyisocyanate curing agents, with their broad application range, are expected to play an important role in future developments.
The future of curing agents lies in multi-functionality, high performance, flame resistance, toughness, latency, energy efficiency, and environmental friendliness. Special attention is being given to sustainable solutions that support green manufacturing and reduce environmental impact.
Improve the survival rate of young animals, disposable umbilical cord clamps for pigs, cattle and sheep, which are practical, convenient and sanitary;
The interface is stable and not easy to loosen: the tail interface uses the internal buckle J-shaped embedding design, which has good stability;
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