1、Curing reactions of epoxy powder coatings in perspectives of chemical

The properties of the cured products of epoxy powder coatings are dominated by the curing systems. This review discusses the types, reaction principles, characteristics of curing agents and accelerators that participate in the curing reaction with different epoxy resins.

2、The epoxy resin system: function and role of curing agents

Curing agents are critical components of aqueous epoxy resin systems. Unfortunately, its uses and applications are restricted because of its low emulsifying yields. Epoxy resins are frequently used in electrical devices, castings, packaging, adhesive, corrosion resistance, and dip coating.

3、Effect of Curing Agent Type on Curing Reaction Kinetics of Epoxy Resin

In this paper, low molecular weight polyamides, aromatic amines and anhydrides were selected as three kinds of curing agents and their isothermal viscosity-time properties were studied to...

4、Current situation and development trend of reactive epoxy resin curing

Abstract Epoxy resin is a thermoplastic polymer. When curing agent is added to the epoxy resin, a new curing product will be formed. Curing agent changes the properties of epoxy resin to obtain new curing products.

Heterogeneous dynamics in the curing process of epoxy resins

In this study, the microscopic dynamics in the curing process of a catalytic epoxy resin were investigated under different temperature conditions utilizing X-ray photon correlation...

Influence of different composite curing agents on the rapid curing

In particular, effective formulations are designed for mixing fast and slow curing agents, studying their effects on the curing behavior, curing quality, and mechanical properties of...

HARDENER FOR ULTRA

The new high-solid curing agent (“Ancamine 2844”) for multi-component spray applica-tions provides an ultra-fast curing property with very good hardness development at ambient temperature and 5 °C with excel-lent carbamation resistance, as well as corro-sion resistance of up to 3000 h in salt spray (Table 1).

Curing agents for epoxy resins

These crosslinkers , hardeners or curing agents as they are widely known, promote cross-linking or curing of epoxy resins. Curing can occur by either homopolymerisation initiated by a catalytic curing agent or a polyaddition/copolymerisation reaction with a multifunctional curing agent.

A critical review of dynamic bonds containing curing agents for epoxy

Investigated the mechanical, thermomechanical, thermal, and recycling properties of the epoxy thermosets cured by developed curing agents. Addressed the challenges, opportunities and emerging trends in the field.

Surface Chemistry and Molecular Dynamics of Epoxy Resin

In this study, we investigate the main reactions occurring on the surface of DEGBA/DEGBF epoxy resin following curing, post-curing, and thermal post-curing processes using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS).

The bulking phenomenon of epoxy resin curing agents refers to significant volume expansion of the curing agent during the curing process of epoxy resin, caused by certain chemical and physical factors. This phenomenon not only affects the performance of the epoxy resin but may also adversely impact the curing process. Below, we explore the causes, effects, and countermeasures for the bulking of epoxy resin curing agents.

I. Causes of Bulking in Epoxy Resin Curing Agents

1. Temperature Effects

• The reaction rate between epoxy resin and curing agents is significantly influenced by temperature. When temperature rises, the reaction accelerates, and molecular movement of the curing agent intensifies, leading to enhanced interactions between curing agent molecules, which can cause volume expansion.
• At high temperatures, the volatilization rate of small molecules in the curing agent increases, reducing the number of remaining curing agent molecules, which also contributes to volume expansion.

2. Humidity Effects

• High humidity environments accelerate the condensation of airborne water vapor, forming droplets on the resin surface and altering its surface tension. Such changes in surface tension may disrupt the interfacial interaction between the curing agent and resin, preventing the curing agent from fully penetrating the resin and compromising the curing effect.
• Under humid conditions, moisture content in the curing agent increases, and the migration and diffusion of water within the curing agent are restricted, further influencing volume changes.

3. Type and Dosage of Curing Agent

• Different curing agents have varying chemical structures and thermal stability, leading to differences in volume expansion. Generally, aromatic curing agents exhibit greater volume expansion compared to aliphatic ones.
• The dosage of the curing agent is a critical factor. Excessive use strengthens interactions between curing agent molecules, causing volume expansion.

II. Effects of Bulking

1. Performance Impacts

• Volume expansion leads to structural deformation of the epoxy resin, reducing its mechanical properties, such as tensile strength and compressive strength.
• Increased porosity within the epoxy resin due to volume expansion diminishes its water resistance and chemical resistance.

2. Process Impacts

• Bulking may extend curing time, lowering production efficiency. Practical operations often require adjustments to curing parameters to accommodate volume changes.
• Post-curing defects, such as bubbles or cracks, may arise from volume expansion, affecting the appearance and functional performance of the final product.

III. Countermeasures

1. Select Appropriate Curing Agent Types and Dosages

• Choose curing agents suited to specific needs and control dosages meticulously to avoid volume expansion issues caused by overuse or underuse.

2. Environmental Control

• Maintain consistent temperature and humidity during curing to minimize environmentally induced volume expansion.
• In high-humidity environments, use dehumidification equipment to mitigate moisture-related impacts.

3. Optimize Production Processes

• Adjust curing parameters (e.g., temperature, duration) to adapt to volume expansion effects.
• Incorporate additives like plasticizers or stabilizers during curing to improve material performance and process adaptability.

4. Inspection and Evaluation

• Regularly inspect the quality indicators of epoxy resin and curing agents to ensure desired material properties.
• Refine curing processes based on inspection results to enhance production efficiency and product quality.

the bulking of epoxy resin curing agents is a complex issue requiring comprehensive analysis and multifaceted solutions. By selecting suitable curing agents, controlling environmental conditions, optimizing processes, and conducting rigorous inspections, the challenges posed by bulking can be effectively addressed, thereby improving material performance and production efficiency.