Epoxy-Terminated Polyester Adhesive Viscosity Control
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Solution Overview
Problem
Existing epoxy-terminated compounds do not effectively react with polyamines to form adhesive compositions with desirable low viscosity over a wide temperature range, limiting their use in laminating adhesives.
Innovation Solution
A two-part composition comprising an epoxy-terminated polyester with specific structural features and an epoxy curing agent, each molecule of which has two or more active hydrogen atoms, is used to bond substrates, with the epoxy terminated polyester having a preferred Epoxide Equivalent Weight (EEW) and number-average molecular weight, and the composition is characterized by a low level of low molecular weight species.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional epoxy-terminated compounds are used, then they can form polymers with high molecular weight, but they do not react effectively with polyamines and have high viscosity over a wide temperature range
Solution Approach 1:
The patent changes the chemical structure parameters of the epoxy-terminated compound by incorporating specific polyester backbones with controlled molecular weights and epoxide group distributions. This structural modification enables effective reaction with polyamines while maintaining low viscosity across the temperature range of 25°C to 70°C, directly resolving the contradiction between reactivity and viscosity.
Solution Approach 2:
The invention creates a composite adhesive system by combining epoxy-terminated polyester compounds with polyamines in a two-part formulation. This composite approach allows the epoxy component to provide structural integrity and the polyamine to enhance reactivity and reduce viscosity, achieving both high reliability and ease of operation simultaneously.
2Strength
If epoxy-terminated compounds with high molecular weight are used, then polymer strength is improved, but viscosity increases limiting handling properties
Solution Approach 1:
The patent optimizes the molecular weight parameters of the epoxy-terminated polyester to a specific range that balances strength and handleability. By controlling the number-average molecular weight and the distribution of epoxide groups, the formulation achieves sufficient adhesive bond strength while maintaining low enough viscosity for effective handling and application.
Solution Approach 2:
The adhesive system exhibits dynamic viscosity characteristics that change with temperature and time. The formulation is designed to have lower viscosity at application temperatures for ease of handling, then develops optimal strength as the polymer network forms during curing, capturing the dynamic nature of the material's performance.
3Ease of operation
If epoxy-terminated compounds are designed for low viscosity, then handling properties improve, but reaction effectiveness with polyamines decreases
Solution Approach 1:
The patent modifies the chemical parameters of the epoxy-terminated compound by incorporating specific polyester structures that provide low viscosity while maintaining sufficient epoxide group reactivity. The controlled molecular weight and epoxide group distribution ensure effective reaction with polyamines despite the reduced viscosity, resolving the contradiction between ease of operation and reaction effectiveness.
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 composition provides a strong adhesive bond with improved viscosity characteristics over a temperature range of 25°C to 70°C, ensuring effective bonding and handling properties.
Implementation Method 1
epoxy-terminated compounds may undergo chemical reactions either with themselves or with one or more co-reactant to form polymers that have high molecular weight and/or are crosslinked
Data Source
AI summary
Provided is a two-part composition comprising A) An epoxy terminated polyester having the structure (IV, V) wherein R1 -is G (II)- is, j is 0 to 5,- R2 -is a divalent organic group, -R22 -is a divalent alkyl group, and -R22 -is a divalent alkyl group. B) one or more epoxy curing agent, each molecule of which comprises two or more active hydrogen atoms that are each capable of reacting with an epoxy group.