Dual Allyl Methacrylate Coatings for Oxygen Inhibition
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Solution Overview
Problem
Peroxide-cured (meth)acrylate resin coating compositions face challenges with oxygen inhibition, leading to incomplete curing, surface defects, and poor adhesion, particularly in solvent-free systems, due to the instability of additives and interactions with metal driers, which results in issues like wrinkling, orange peel, and reduced scratch/mar resistance.
Innovation Solution
The use of dual allyl and (meth)acrylate functional crosslinking monomers, such as diallyl trimethylolpropane methacrylate, in two-component compositions eliminates the need for paraffin wax and volatile additives, allowing for effective curing in the presence of oxygen and improving surface properties without compromising stability or introducing additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If paraffin wax is added to provide oxygen barrier, then surface cure is improved, but surface properties deteriorate and intercoat adhesion decreases
Solution Approach 1:
The invention removes paraffin wax from the coating composition entirely, replacing its oxygen barrier function with a different mechanism. The crosslinking monomer system enables effective curing without requiring wax migration and crystallization at the surface, thereby eliminating the adhesion problems caused by wax presence.
Solution Approach 2:
The invention changes the chemical parameters of the coating system by introducing dual-functional crosslinking monomers with specific reactivity characteristics. These monomers enable curing at different rates at the surface versus bulk, providing oxygen barrier functionality through chemical reaction rather than physical wax migration.
2Reliability
If volatile crosslinking monomers like dicyclopentenyl derivatives are used to promote surface cure, then surface cure is improved, but safety and handling concerns increase due to volatility and odor
Solution Approach 1:
The invention selects crosslinking monomers with specific molecular weight, volatility, and reactivity parameters. The chosen monomers have lower volatility and odor compared to dicyclopentenyl derivatives while maintaining adequate surface cure promotion through their dual allyl and (meth)acrylate functionality and sensitivity to oxidative reactions.
Solution Approach 2:
The invention uses composite monomer systems combining allyl and (meth)acrylate functional groups in single molecules. This composite structure provides both the surface cure promotion through oxidative sensitivity and reduced volatility compared to purely allylic compounds.
3Reliability
If allyl ether derivatives like PAGE are used to promote surface cure, then surface cure is improved, but viscosity increases making them impractical for some coating applications
Solution Approach 1:
The invention selects crosslinking monomers with optimized molecular weight and structural parameters that balance surface cure promotion with acceptable viscosity. The dual-functional monomers used have lower molecular weights compared to PAGE derivatives, maintaining fluidity suitable for coating applications while retaining oxidative sensitivity for surface cure.
4Stability of the object's composition
If oximes are added to block metal drier oxidative reactions and extend package stability, then package stability is improved, but rate of cure at surface slows down leading to coating defects
Solution Approach 1:
The invention removes oximes from the formulation entirely. Package stability is achieved through the inherent stability of the dual-functional crosslinking monomers and peroxide system without requiring oxime blockers. The monomers are stable in air and when mixed with metal drier, eliminating the need for cure rate suppression during storage.
Solution Approach 2:
The invention designs the coating composition with pre-selected monomers that have built-in stability characteristics, eliminating the need for preliminary protective measures like oxime addition. The monomers are inherently stable during storage and only become reactive under curing conditions.
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
This approach enables rapid and uniform curing with enhanced surface hardness and scratch/mar resistance, reducing defects like wrinkling and orange peel, while maintaining package stability and eliminating the need for additional stabilizers or wax, resulting in improved performance in concrete coatings and other applications.
Implementation Method 1
Cobalt driers undergo oxidative reactions that reduce the decomposition temperature of the peroxide
Implementation Method 2
peroxide curable (meth)acrylate resin coating compositions
Implementation Method 3
these monomers are also known in the industry to be volatile and odorous which may present safety and handling concerns
Implementation Method 4
these allyl ether and PAGE derivatives present package stability issues if they are packaged with the metal drier in the resin component
Data Source
AI summary
A crosslinking monomer for a peroxide cure composition is a dual functional monomer and has at least two allyl groups and at least one (meth)acrylate group. A composition comprises the crosslinking monomer and at least one (meth)acrylate monomer. A two-part peroxide composition comprises the crosslinking monomer, at least one (meth)acrylate monomer, and a peroxide initiator. The compositions, which may be wax-free or solvent-free or both, are useful as protective coatings or sealants for concrete and other substrates.