Modified amine low-temperature curing agent (RH01): A core additive that breaks through the bottleneck of low-temperature construction of epoxy resin

Modified Amine Low-Temperature Curing Agent (RH01): A Core Additive Breaking Through the Bottleneck of Low-Temperature Epoxy Resin Construction

In the myriad applications of epoxy resins, low-temperature curing has always been a major technical challenge hindering industry development. Outdoor construction in frigid regions, mass production in winter factories, and bonding of temperature-sensitive precision components all urgently require a curing agent that can cure efficiently at low temperatures without sacrificing final performance. Modified amine low-temperature curing agent (RH01) was developed to address this need. With innovative molecular modification technology, it breaks the curse of traditional amine curing agents being “slow to cure at low temperatures and poor at high temperatures,” becoming the “golden partner” for epoxy resins in low-temperature conditions. It safeguards winter construction and low-temperature operations in multiple fields such as coatings, adhesives, flooring, and potting.

I. Core Operating Principle

Modified amine low-temperature curing agent (RH01) is a novel curing agent prepared by modifying the molecular structure of aliphatic and cyclic amines and grafting active groups. Its core advantage stems from its unique chemical structure and reaction mechanism.

From a molecular structure perspective, RH01 retains the active primary and secondary amine groups found in traditional amine curing agents. Simultaneously, by grafting flexible segments and active promoting groups, the reactivity and compatibility of the molecule are optimized. At low temperatures (-10℃ to 15℃), the active amine groups in the RH01 molecule can rapidly undergo ring-opening addition reactions with the epoxy groups of epoxy resins, initiating the cross-linking and curing process without additional heating or the addition of accelerators.

The key to its rapid low-temperature curing lies in the catalytic effect of the active promoting groups—these groups lower the activation energy of the reaction between epoxy groups and amine groups, accelerating the cross-linking polymerization of molecular chains, ensuring the orderly progress of the curing reaction even at temperatures close to freezing. Meanwhile, the grafted flexible segments are evenly dispersed in the cured three-dimensional network structure, effectively alleviating the internal stress of the cured epoxy resin and avoiding cracking and delamination problems caused by uneven shrinkage during low-temperature curing.

I. Core Operating Principle

Modified amine low-temperature curing agent (RH01) is a novel curing agent prepared by modifying the molecular structure of aliphatic and cyclic amines and grafting active groups. Its core advantage stems from its unique chemical structure and reaction mechanism.

From a molecular structure perspective, RH01 retains the active primary and secondary amine groups found in traditional amine curing agents. Simultaneously, by grafting flexible segments and active promoting groups, the reactivity and compatibility of the molecule are optimized. At low temperatures (-10℃ to 15℃), the active amine groups in the RH01 molecule can rapidly undergo ring-opening addition reactions with the epoxy groups of epoxy resins, initiating the cross-linking and curing process without additional heating or the addition of accelerators.

The key to its rapid low-temperature curing lies in the catalytic effect of the active promoting groups—these groups lower the activation energy of the reaction between epoxy groups and amine groups, accelerating the cross-linking polymerization of molecular chains, ensuring the orderly progress of the curing reaction even at temperatures close to freezing. Meanwhile, the grafted flexible segments are evenly dispersed in the cured three-dimensional network structure, effectively alleviating the internal stress of the cured epoxy resin and avoiding cracking and delamination problems caused by uneven shrinkage during low-temperature curing.

Unlike traditional low-temperature curing agents, RH01 achieves a dual balance between “rapid low-temperature curing” and “stable high-temperature performance.” After the curing reaction is complete, its molecular chains are tightly cross-linked with the epoxy resin, forming a dense structure with stable chemical bonds, maintaining excellent mechanical and chemical resistance even under harsh environments such as high temperature and humidity.

II. Key Technical Parameters

Precise technical parameters are the core guarantee for RH01’s adaptability to various low-temperature construction scenarios. The following are the core technical indicators of the modified amine low-temperature curing agent (RH01):

Indicator Name: Technical Parameter
Indicator Name: Technical Parameter
Appearance: Light yellow transparent liquid
Amine Value (mgKOH/g): 380～420
Color (Platinum-Cobalt Color Number): ≤80
Viscosity (25℃, mPa·s): 200～500
Density (25℃, g/cm³): 0.98～1.02
Active Hydrogen Equivalent: 65～75
Flash Point (Closed Cup, °C): ≥70
Gel Time (25℃, 1:1 with E-51): 15～25min
Gel Time (5℃, 1:1 with E-51): 40～60min
Complete Curing Time (-5℃): ≤48h
Applicable Temperature Range: -10℃～40℃ Shelf life (25℃, sealed) ≥12 months

III. Key Performance Features

1. Ultra-low Temperature Rapid Curing, No Heating Required

RH01 possesses exceptional low-temperature curing capabilities, capable of curing epoxy resins normally within a wide temperature range of -10℃ to 15℃, without the need for additional heating equipment or the addition of curing accelerators. At 5℃, when mixed with E-51 epoxy resin at a 1:1 ratio, it gels in 40-60 minutes and fully cures within 48 hours; even under extremely cold conditions of -5℃, it can achieve complete curing within 72 hours, with curing efficiency far exceeding traditional fatty amine curing agents. This characteristic completely solves the efficiency problems of outdoor construction in winter and low-temperature factory production, significantly shortening the construction period and reducing construction costs.

2. Excellent Cured Product Performance, Balancing High and Low Temperature Performance

Traditional low-temperature curing agents often suffer from the shortcoming of “fast curing but poor performance,” while RH01, thanks to advanced modification technology, perfectly balances curing speed and cured product performance. The cured epoxy resin system exhibits a tensile strength of 45–55 MPa, a flexural strength ≥80 MPa, an impact strength ≥12 kJ/m², and a hardness (Shore D) ≥85. It also possesses excellent resistance to high and low temperature cycling, showing no cracking, deformation, or performance degradation after repeated testing within a temperature range of -40℃ to 120℃. Furthermore, the cured product exhibits excellent chemical corrosion resistance, with acid and alkali resistance, salt spray resistance, and organic solvent resistance all meeting high industrial-grade standards, satisfying the demands of harsh operating conditions.

3. Good compatibility, suitable for various epoxy resin systems

RH01 has excellent compatibility with most epoxy resins, including bisphenol A, bisphenol F, and phenolic resins. The mixed system is uniform and transparent, without stratification or precipitation. Simultaneously, it is perfectly compatible with various fillers (such as talc, calcium carbonate, and fumed silica) and additives (such as leveling agents, defoamers, and coupling agents) in epoxy resin systems without adverse reactions. It can be widely used in the preparation of various products such as solvent-free epoxy coatings, epoxy adhesives, epoxy floor paints, and electronic potting compounds.

4. Low toxicity and environmentally friendly, with high construction safety.

RH01, through molecular modification, significantly reduces the volatility and irritating odor of traditional amine curing agents. Its free amine content is ≤0.5%, far below the national standard limit. The product is non-toxic and non-irritating, complying with international environmental standards such as RoHS and REACH. It will not harm the health of operators during construction and also avoids defects such as pinholes and craters in the paint film caused by volatile substances. Furthermore, RH01 has a flash point ≥70℃, classifying it as a non-flammable liquid, significantly improving safety during storage, transportation, and construction.

5.Flexible mixing ratio and easy application.

RH01 has a wide mixing ratio range with epoxy resin, which can be flexibly adjusted within the range of 1:1 to 1:1.5 according to the required application temperature and curing speed. The mixed system has moderate viscosity and good fluidity, and can be applied by brushing, spraying, rolling, pouring, and other methods, suitable for substrates of different shapes and materials. Furthermore, the pot life of the system can be adjusted according to temperature; the pot life is extended at low temperatures, facilitating large-area application; at room temperature, the pot life is moderate, preventing application difficulties due to excessively rapid curing.

IV. Wide Range of Applications and Scenarios

(I) Epoxy Coatings and Corrosion Protection

1. Low-Temperature Epoxy Anti-Corrosion Paint: RH01 is the core curing agent for preparing winter outdoor epoxy anti-corrosion paint. It can be used for anti-corrosion coating of steel structure bridges, oil storage tanks, municipal pipelines, ship hulls, and other facilities. Even at -5℃, the paint film can still cure quickly, forming a dense anti-corrosion protective layer. Salt spray resistance can reach over 1000 hours, effectively resisting the erosion of the substrate by harsh environments.
2. Solvent-Free Epoxy Floor Coating: Used for epoxy flooring construction in factories and workshops during winter. No heating curing is required. The cured floor surface is smooth, flat, hard, and has good wear resistance, able to withstand high-frequency rolling by forklifts and trucks. Suitable for industrial plants, logistics warehouses, underground garages, and other similar locations.

(II) Epoxy Adhesives and Sealants

1. Low-Temperature Epoxy Structural Adhesives: Suitable for structural bonding of metal, glass, ceramic, and concrete substrates outdoors in winter, such as in building curtain wall installation, bridge reinforcement, and mechanical equipment maintenance. The cured adhesive layer has high strength and good toughness, with a bond strength ≥30MPa, and will not delaminate or crack even in low-temperature environments.
2. Low-Temperature Electronic Sealants: Used for sealing and protecting electronic components, sensors, and circuit boards in low-temperature environments. The cured adhesive layer has excellent insulation, high and low temperature resistance, and aging resistance, effectively protecting electronic components from moisture, dust, and external force damage.

(III) Epoxy Potting and Composite Materials

1. Low-Temperature Electronic Potting Compounds: Used for potting electronic components such as transformers, capacitors, and motor stators produced in winter. RH01 allows the potting compound to cure rapidly at low temperatures, filling the tiny gaps in the components to form a robust protective shell, improving the reliability and lifespan of electronic equipment. 2. Low-Temperature Epoxy Composites: Used in winter for the preparation of fiberglass and carbon fiber composite products, such as wind turbine blades, yacht hulls, and building decorative panels. RH01 effectively reduces the curing temperature of the resin system, shortens the molding cycle, and ensures the strength and toughness of the composite material, meeting product quality requirements.

(IV) Building Reinforcement and Repair

1. Low-Temperature Epoxy Grouting Material: Used for crack repair, foundation reinforcement, and beam and column reinforcement in building structures during winter. RH01 allows the grouting material to cure rapidly at low temperatures, bonding tightly to the concrete substrate. After curing, it has high strength and low shrinkage, effectively restoring the load-bearing capacity of the building structure.
2. Low-Temperature Epoxy Interface Agent: Used for interface treatment between concrete and reinforcing steel, and between concrete and tiles in winter construction. It can improve interface adhesion and prevent bonding failure caused by excessively low temperatures.

V. Practical Application Results

The superior performance of RH01 has been fully verified in practical applications, providing efficient solutions for winter construction in numerous industries.

A steel structure anti-corrosion engineering company undertook an anti-corrosion coating project for a bridge during winter (ambient temperature -3℃ to 5℃), using RH01 as the curing agent for the epoxy anti-corrosion paint. No heating was required during application; the paint film was surface-drying within 24 hours and fully cured within 48 hours, achieving an adhesion rating of 0. After 1200 hours of salt spray testing, no rust or blistering was observed. Compared to traditional heat-curing methods, the construction period was shortened by 50%, construction costs were reduced by 30%, and the paint film quality far exceeded expectations.

An electronic component manufacturer used RH01-modified epoxy potting compound to encapsulate miniature sensors during winter production. In a 0℃ workshop environment, the potting compound gelled in 60 minutes and fully cured in 72 hours. The insulation resistance of the cured potting layer reached 10¹⁴Ω. After 50 cycles of high and low temperature cycling from -40℃ to 120℃, the sensor performance showed no degradation, and the product qualification rate increased from 95% to 99.8%.

A building reinforcement engineering company reinforced the beams and columns of an old building during winter, using epoxy grout formulated with RH01. At a low temperature of -5℃, the grout exhibited good fluidity, easily injecting into the cracks in the beams and columns. It fully cured in 48 hours, achieving a compressive strength of 60MPa and a bond strength to the concrete substrate ≥5MPa. The reinforcement effect passed the acceptance test of a professional testing agency, far exceeding the design standards.

Conclusion

Modified amine low-temperature curing agent (RH01), with its numerous advantages such as ultra-low temperature rapid curing, excellent cured product performance, good compatibility, and environmental safety, has become a revolutionary product in the field of low-temperature epoxy resin applications. It not only overcomes the temperature limitations of winter construction, but also injects new vitality into the development of industries such as coatings, adhesives, building reinforcement, and electronic potting with its characteristics of “high efficiency, high quality, and low cost.” In future industrial production and infrastructure construction, RH01 will undoubtedly leverage its core strengths to continuously empower more epoxy resin application scenarios under low-temperature conditions, helping the industry achieve higher-quality development.