Phosphate Ester Modified Isocyanate Adhesives for Extended Potlife
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Solution Overview
Problem
Two-component polyurethane-based adhesives often have shortened potlife when phosphate ester polyols are added, which can affect the quality and consistency of laminates, and pose challenges in maintenance and cleaning, especially in applications requiring extended potlife and improved temperature and chemical resistance.
Innovation Solution
The development of two-component adhesive compositions comprising an isocyanate component reacted with a phosphate ester polyol and an isocyanate-reactive component, with a stoichiometric ratio of NCO/OH from 1.0 to 5.0, allowing for extended potlife while maintaining improved temperature and chemical resistance, suitable for both traditional and higher-reactivity laminating techniques, and can be solventless or solvent-based.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphate ester polyols are added to improve temperature and chemical resistance, then temperature resistance and chemical resistance are improved, but potlife is shortened
Solution Approach 1:
The adhesive system is divided into two separate components: Component A (isocyanate component) and Component B (isocyanate-reactive component containing phosphate ester polyol). This segmentation allows the reactive phosphate ester polyol to be isolated until mixing, preventing premature reaction and extending potlife while maintaining the temperature and chemical resistance benefits when applied.
Solution Approach 2:
The phosphate ester polyol is pre-incorporated into Component B at controlled concentrations (1-20% by weight) before use. This preliminary preparation ensures the adhesion promoter is ready to enhance temperature and chemical resistance upon mixing, while the separate storage of components prevents premature reaction and extends the working potlife.
2Reliability
If phosphate ester polyols are added to improve temperature and chemical resistance, then temperature resistance and chemical resistance are improved, but laminate quality consistency deteriorates
Solution Approach 1:
The concentration of phosphate ester polyol in Component B is precisely controlled within the range of 1-20% by weight. This parameter optimization ensures sufficient adhesion promoter is present for improved temperature and chemical resistance, while avoiding excessive concentrations that would cause premature reaction and inconsistent laminate quality.
3Reliability
If phosphate ester polyols are added to improve temperature and chemical resistance, then temperature resistance and chemical resistance are improved, but maintenance and cleaning difficulty increases
Solution Approach 1:
By separating the adhesive into two components with the phosphate ester polyol confined to Component B, the system maintains extended potlife and consistent application properties. This segmentation prevents the adhesion promoter from causing premature skin formation or inconsistent curing that would complicate maintenance and cleaning operations.
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 compositions demonstrate enhanced bond strength, temperature resistance, and chemical resistance with extended potlife, ensuring consistent laminate quality and ease of maintenance, suitable for food packaging, pharmaceutical packaging, and industrial laminations.
Implementation Method 1
The two components are typically combined in a predetermined ratio, or 'premixed,' and then applied on a surface of a first substrate ('carrier web'). The surface of the first substrate is then brought together with a surface of a second substrate to form a laminate structure. The adhesive is then cured, either at room temperature or elevated temperature, thereby bonding the substrates together.
Implementation Method 2
To improve temperature and chemical resistance of the adhesives, adhesion promoters, such as silane coupling agents, titanate coupling agents, aluminate coupling agents, as well as epoxy resins, phosphoric acid, and phosphate esters are sometimes used.
Implementation Method 3
The adhesive compositions show improved bond strength, temperature resistance, and chemical resistance, while maintaining extended potlife
Implementation Method 4
The adhesive compositions show improved bond strength, temperature resistance, and chemical resistance
Data Source
AI summary
The disclosed adhesive compositions comprise (A) an isocyanate component comprising an isocyanate-terminated prepolymer that is the reaction product of a polyisocyanate and an isocyanate-reactive mixture comprising a phosphate ester polyol. The disclosed adhesive compositions further comprise (B) an isocyanate-reactive component polyol component comprising a polyol. In some embodiments, methods for preparing two-component adhesives formulations are disclosed comprising preparing an isocyanate component comprising an isocyanate-terminated prepolymer by reacting a polyisocyanate with an isocyanate-reactive mixture comprising a phosphate ester polyol and preparing an isocyanate-reactive component comprising a polyol. The methods further comprise mixing the isocyanate component and the isocyanate-reactive component at a stoichiometric ratio (NCO/OH) of from about 1.0 to about 5.0. Methods for forming laminate structures, and the laminate structures themselves, are also disclosed.