Polycarbamate Aqueous Composition for Low-Temperature Crosslinking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current crosslinking technologies for low molecular polymers used in coating applications face challenges such as high toxicity, high cost, and the need for elevated temperatures, particularly with polyisocyanates and aminoplast resins, which also result in unsuitable levels of volatile organic compounds (VOC) and limited crosslinking at ambient conditions.
Innovation Solution
A crosslinkable aqueous composition comprising a polycarbamate with at least 2 carbamate functional groups, a polyaldehyde with two aldehyde groups, and an acid catalyst, capable of crosslinking at temperatures below 80°C, reducing toxicity and enabling low-temperature curing while maintaining high crosslinking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyisocyanate crosslinkers are used, then low temperature cure is achieved with superior coating properties, but high toxicity and high cost occur
Solution Approach 1:
The patent replaces expensive and toxic polyisocyanate crosslinkers with a biodegradable alternative system consisting of polyol, carbonyl compound, and catalyst. This disposable-like approach uses readily available, non-toxic materials that can be easily disposed of without environmental harm, achieving both low cost and low toxicity while maintaining low-temperature curing capability
Solution Approach 2:
The invention changes the chemical parameters of the crosslinking system by using different functional groups (hydroxyl, carbonyl, isocyanate) in specific combinations and ratios. By adjusting the types and amounts of polyol, carbonyl compound, and catalyst, the system achieves effective crosslinking at low temperatures without the toxicity associated with traditional polyisocyanate systems
2Temperature
If polyisocyanate crosslinkers are used, then low temperature cure is achieved, but high cost occurs
Solution Approach 1:
The patent substitutes expensive polyisocyanate crosslinkers with inexpensive, commercially available materials including common polyols (polyethylene glycol, polypropylene glycol), carbonyl compounds (acetaldehyde, propionaldehyde), and catalysts. These materials are significantly cheaper than polyisocyanates while providing equivalent or superior performance in low-temperature curing applications
3Ease of manufacture
If aminoplast resins are used as crosslinkers, then lower cost and good coating performance are achieved, but high temperature curing is required and residual formaldehyde toxicity occurs
Solution Approach 1:
The invention fundamentally changes the curing temperature parameter by using a chemical system (polyol-carbonyl-isocyanate) that reacts effectively at low temperatures, unlike aminoplast resins that require high temperatures. The reaction kinetics are optimized through catalyst selection and formulation to achieve rapid crosslinking at ambient or low temperatures, eliminating the need for high-temperature processing
4Ease of manufacture
If aminoplast resins are used as crosslinkers, then lower cost is achieved, but residual formaldehyde toxicity occurs
Solution Approach 1:
The patent extracts and eliminates the harmful formaldehyde component from the crosslinking system by replacing aminoplast resins with an alternative chemistry based on polyol, carbonyl compound, and isocyanate. This extraction of the toxic element is achieved by selecting materials that do not release formaldehyde, thereby maintaining cost-effectiveness while removing the harmful byproduct
Solution Approach 2:
The invention converts the potential harm of using inexpensive crosslinkers (which often release toxic formaldehyde) into a benefit by selecting specific low-cost materials (polyol, carbonyl compound, catalyst) that are both economical and non-toxic. The formulation transforms what would be a harmful chemical pathway into a safe and effective crosslinking mechanism
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 solution provides a low-temperature crosslinking process with reduced toxicity and VOC emissions, achieving high crosslinking density and improved properties like water resistance and chemical resistance, suitable for various substrates without the need for high-temperature curing.
Implementation Method 1
an acid catalyst; and wherein said composition is capable of being crosslinked at a temperature in range of less than 80° C. upon removal of a substantial portion of water
Implementation Method 2
a crosslinked composition derived from the inventive crosslinkable aqueous composition comprising carbamate ester linkages prepared by the reaction of: (a) a polycarbamate comprising at least an average of 2.0 carbamate functional groups; and (b) a polyaldehyde comprising at least two aldehyde groups
Data Source
AI summary
The instant invention provides a crosslinkable aqueous composition, method of producing the same, crosslinked compositions, and method of producing the same. The crosslinkable composition comprising: an aqueous dispersion comprising; (a) water; (b) a polycarbamate comprising at least an average of 2.0 carbamate functional groups; (c) a polyaldehyde comprising at least two aldehyde groups; (d) an acid catalyst; and (e) optionally one or more surfactants; wherein said aqueous dispersion has a pH in the range of less than 7; and wherein said composition is capable of being crosslinked at a temperature in range of less than 80° C. upon substantial removal of water.