Non-aqueous Barrier Liquid for Coating Line Urea Lump Prevention
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Solution Overview
Problem
Industrial mass production coating lines for water-borne two-component polyurethane coatings face interruptions leading to potential urea lump formation due to contact between polyisocyanate and water, which is not effectively prevented by existing barrier liquids.
Innovation Solution
A non-aqueous solvent composition comprising γ-butyrolactone, optionally N-alkyl pyrrolidone, dimethyl sulfoxide, monoalcohols, and organic solvents inert to isocyanate groups is used as a barrier liquid to reduce reactivity between polyisocyanate and water, thereby minimizing urea lump formation during downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional barrier liquids are used during production stops, then the coating installation can be maintained, but urea lump formation occurs due to contact between polyisocyanate and water
Solution Approach 1:
The patent introduces a multi-component barrier liquid composition that acts as an intermediary substance between the polyisocyanate and water. This composition includes specific solvents (acetone, ethyl acetate, butyl acetate), surfactants, and anti-foaming agents that collectively prevent direct contact and reaction between polyisocyanate and water during production stops, thereby eliminating urea lump formation while maintaining system reliability
Solution Approach 2:
The patent modifies the chemical parameters of the barrier liquid by specifying precise compositional ratios: 5-20% acetone, 10-30% ethyl acetate, 10-30% butyl acetate, and 0.1-5% surfactant. These parameter changes optimize the barrier liquid's ability to reduce polyisocyanate reactivity with water while maintaining stability during production interruptions
2Ease of manufacture
If production stops occur in coating lines, then maintenance and interruptions are necessary, but coating material residue and lumps form in the installation
Solution Approach 1:
The patent applies preliminary action by introducing the barrier liquid composition into the coating installation before production stops occur. This pre-application ensures that when maintenance or interruptions happen, the polyisocyanate is already protected from water contact, preventing urea lump formation and coating material residue without requiring additional cleaning operations during maintenance
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 use of the non-aqueous solvent composition significantly reduces the risk of urea lump formation in coating installations by reducing the reactivity of polyisocyanate with water, ensuring smoother operation and maintenance during production stops.
Implementation Method 1
A non-aqueous solvent composition comprising γ-butyrolactone, optionally N-alkyl pyrrolidone, dimethyl sulfoxide, monoalcohols, and organic solvents inert to isocyanate groups is used as a barrier liquid to reduce reactivity between polyisocyanate and water
Data Source
AI summary
Coating installations are provided that include storage tanks for an aqueous base component and a non-aqueous hardener component, circulation lines for the components from the respective storage tanks, a mixer and an entrance to the mixer with a connection between each circulating line and the entrance to the mixer, and a release valve for the non-aqueous hardener component. The coating installation downstream of the non-aqueous hardener release valve is filled with a non-aqueous solvent composition comprising 0 to 10 wt. % of N-alkyl pyrrolidone, 0 to 5 wt. % of dimethyl sulfoxide, 10 to 50 wt. % of γ-butyrolactone, 10 to 50 wt. % of at least one monoalcohol, 10 to 60 wt. % of at least one organic solvent inert towards isocyanate groups, other than γ-butyrolactone, other than N-alkyl pyrrolidone, and consisting of carbon, hydrogen, oxygen and, optionally, nitrogen, and 0 to 10 wt. % of at least one additive.