Adhesive Composition High-Temperature Resistance
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Solution Overview
Problem
Existing one-component polyurethane adhesives exhibit poor high-temperature resistance, leading to adhesive failure and reduced service life of bonded articles, especially when operating temperatures approach the activation temperature of the adhesives.
Innovation Solution
An adhesive composition comprising an anionic aqueous polyurethane dispersion with a polyurethane enthalpy of fusion of at least 3 J/g and an aqueous polyacrylate primary dispersion with a hydroxyl content of 0.5% to 1.8% by weight, combined in specific weight percentages, providing enhanced high-temperature resistance and bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If one-component polyurethane adhesives are used for ease of operation, then ease of operation is improved, but high-temperature resistance deteriorates
Solution Approach 1:
The patent uses a composite adhesive system combining polyester-based aqueous polyurethane dispersion and carboxylic acid-based aqueous polymer dispersion. The polyurethane component provides ease of operation and initial bonding, while the carboxylic acid component enhances high-temperature resistance through calcium salt formation and improved thermal stability, resolving the contradiction between ease of operation and high-temperature resistance.
Solution Approach 2:
The patent modifies the chemical composition parameters of the adhesive by incorporating carboxylic acid-based polymers with specific glass transition temperatures (50-150°C) and controlling the weight ratio between polyurethane and carboxylic acid components (9:1 to 1:9). This parameter optimization enables the adhesive to maintain both ease of operation and high-temperature resistance.
2Speed
If operating temperature approaches activation temperature of the adhesive, then bonding speed is improved, but adhesive failure occurs
Solution Approach 1:
The patent incorporates carboxylic acid-based aqueous polymer dispersion as a preventive measure before thermal activation occurs. This component forms a thermally stable calcium salt structure that cushions against the risks of adhesive failure when operating temperatures approach activation temperatures, allowing fast bonding while preventing degradation.
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 adhesive composition demonstrates good high-temperature resistance and aging resistance, with bonded articles showing reduced peeling distances and increased bonding force, even at elevated temperatures, thereby improving the service life and quality of bonded articles.
Implementation Method 1
the polyester chains of the aqueous polyurethane dispersion begin to recrystallize, so that the bonding force of the adhesive reaches high strength quickly
Implementation Method 2
Thermal activation indicates that the aqueous polyurethane dispersion is melted and activated at a certain temperature
Implementation Method 3
the physical bonding force generated by the close contact between the adhesive and the substrate, and further enhanced by the hydrogen bond of the polyurethane on the substrate
Data Source
Figure 1~2
AI summary
The invention relates to an adhesive composition, the preparation and use of said composition, and an article obtained by bonding using said composition. The adhesive composition comprises: a. an anionic aqueous polyurethane dispersion, which contains a polyurethane with enthalpy of fusion of at least 3 J/g, wherein the enthalpy of fusion is measured by DSC at 20°C-100°C of the first heating curve according to DIN 65467; and wherein said aqueous polyurethane dispersion has a hydroxyl content of 0.001% by weight to 0.085% by weight, relative to the total weight of the aqueous polyurethane dispersion; and b. an aqueous polyacrylate primary dispersion with a hydroxyl content of 0.5% by weight to 1.8% by weight, relative to the total weight of the aqueous polyacrylate primary dispersion; wherein the amount of the aqueous polyurethane dispersion is 30% by weight to 91% by weight, and the amount of the aqueous polyacrylate primary dispersion is 9% by weight to 70% by weight, the above weight percentages being relative to the total weight of the adhesive composition. The adhesive composition of the present invention has good high-temperature resistance.