Polymercaptan Curing Agent for Epoxy Resins
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Solution Overview
Problem
Existing polymercaptan curing agents for epoxy resins face issues such as poor moisture and heat resistance, strong odor, and complex processing due to ester bonds and solid state at room temperature, leading to ineffective bonding and short working life in high-humidity environments.
Innovation Solution
A novel polymercaptan compound represented by formula (I), which is a liquid at room temperature, prepared through a method involving substitution, radical addition, and hydrolysis reactions, providing good moisture resistance, heat resistance, and low odor, eliminating the need for additional coupling agents and simplifying the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymercaptan curing agents with ester bonds are used, then the curing agent can be synthesized, but the bonding strength and moisture resistance deteriorate in high humidity environments
Solution Approach 1:
The patent removes the ester bond structure from the polymercaptan curing agent molecule. By extracting this problematic functional group, the cured epoxy resin achieves excellent water and moisture resistance without compromising bonding strength, directly resolving the contradiction between bonding strength and moisture resistance.
Solution Approach 2:
The patent employs a composite molecular structure combining polymercaptan with isocyanurate rings. This composite structure provides both the desired curing performance and enhanced environmental resistance, achieving reliable bonding strength while maintaining excellent moisture resistance through the synergistic effects of the molecular architecture.
2Reliability
If mercaptoalkyl glycolurea is used as curing agent, then moisture resistance and heat resistance are improved, but the agent is solid at room temperature causing crystal precipitation
Solution Approach 1:
The patent modifies the molecular structure parameters of the polymercaptan compound, specifically adjusting the chain length and molecular weight to achieve a liquid state at room temperature. This parameter change eliminates crystal precipitation issues while maintaining the excellent moisture and heat resistance properties.
Solution Approach 2:
The patent introduces flexible alkyl chain segments into the molecular structure at specific positions. This local modification of molecular architecture provides liquid流动性 at room temperature while preserving the functional groups responsible for moisture and heat resistance, resolving the contradiction between ease of operation and reliability.
3Object-affected harmful factors
If trimercaptopropyl isocyanurate is used as curing agent, then water resistance is improved, but strong sulfur odor is emitted at room temperature
Solution Approach 1:
The patent introduces aromatic ring structures as intermediary groups between the mercapto functional groups. These aromatic intermediaries effectively mask the sulfur odor while maintaining the water resistance properties, resolving the contradiction between water resistance and odor control.
Solution Approach 2:
The patent creates a composite molecular structure where aromatic hydrocarbon frameworks are combined with mercapto-functionalized segments. This composite architecture provides both excellent water resistance and significantly reduced sulfur odor through the aromatic ring's odor-masking effect.
4Temperature
If polymercaptan curing agent is used, then low-temperature curing is achieved, but the working life is short due to rapid reaction
Solution Approach 1:
The patent designs the polymercaptan compound with dynamic molecular characteristics that enable low-temperature reactivity while controlling the reaction rate. The molecular structure allows flexible adjustment of reaction kinetics, achieving low-temperature curing capability while maintaining adequate working life through optimized molecular architecture.
Solution Approach 2:
The patent adjusts molecular weight and chain length parameters of the polymercaptan compound to modulate reaction kinetics. By optimizing these parameters, the curing agent achieves low-temperature curing performance while the extended molecular chains provide sufficient working life by controlling the reaction rate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The polymercaptan compound enhances the stability and performance of epoxy resin compositions by maintaining bonding strength and heat resistance, reducing storage stability risks, and extending working life while minimizing odor and processing complexity.
Implementation Method 1
A novel polymercaptan compound represented by formula (I), which is a liquid at room temperature, prepared through a method involving substitution, radical addition, and hydrolysis reactions
Implementation Method 2
A novel polymercaptan compound represented by formula (I), which is a liquid at room temperature, prepared through a method involving substitution, radical addition, and hydrolysis reactions
Implementation Method 3
A novel polymercaptan compound represented by formula (I), which is a liquid at room temperature, prepared through a method involving substitution, radical addition, and hydrolysis reactions
Data Source
AI summary
The present disclosure belongs to polymercaptan compounds and application fields thereof, and particularly relates to a polymercaptan compound and a preparation method thereof, a curing agent, a resin composition, an adhesive and a sealant. The polymercaptan compound is represented by formula (I), wherein R1, R2, R3, R5, R7 and R8 are each independently selected from one of a hydrogen atom, an alkyl group with 1-5 carbon atoms and an alkoxy group with 1-5 carbon atoms, R4 and R6 are each independently selected from an alkylene group with 1-5 carbon atoms, and m and n are each independently 0, 1, 2 or 3.