GMA-Free Radiation Curable Composition via Urethane Linkage
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Solution Overview
Problem
Current non-aqueous radiation curable compositions using (meth)acrylated acrylic polymers with pendant hydroxyl groups rely on hazardous glycidyl methacrylate (GMA) and limit the range of available hydroxy functional (meth)acrylate monomers, affecting the polymer's reactivity and tunability for various applications.
Innovation Solution
A non-aqueous radiation curable composition comprising (meth)acrylated acrylic polymers with pendant hydroxyl groups, formed through a reaction between a hydroxy functional ethylenically unsaturated monomer and an ethylenically unsaturated monomer, using an isocyanate group-containing monoadduct that attaches via a urethane linkage, allowing for a broad range of hydroxy functional (meth)acrylate monomers and improved reactivity without GMA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GMA is used to introduce (meth)acrylate groups and hydroxyl groups in the acrylic polymer backbone, then both groups are covalently attached to the polymer, but the number of (meth)acrylate groups is proportional to the number of OH groups introduced and both groups are close to each other causing steric hindrance that reduces reactivity
Solution Approach 1:
The patent uses different monomers for introducing hydroxyl groups and (meth)acrylate groups separately, rather than using GMA which introduces both groups together. This segmentation allows independent control of group placement and reduces steric hindrance between the two functional groups on the polymer backbone.
Solution Approach 2:
The patent employs multiple different monomers (at least two different ethylenically unsaturated monomers) to provide different local chemical environments and functionalities. This allows optimization of reactivity at different locations along the polymer chain, with hydroxyl-bearing monomers and (meth)acrylate-bearing monomers distributed independently.
2Adaptability or versatility
If only mono(meth)acrylate compounds are used for acrylation, then a limited range of (meth)acrylated acrylic polymers can be prepared, but this limits the ability to fine-tune reactivity and properties for different applications
Solution Approach 1:
The patent employs multiple ethylenically unsaturated monomers with different functionalities (hydroxyl-bearing monomers and (meth)acrylate-bearing monomers) that can be combined in various ratios to achieve different polymer properties. This multi-functional approach allows a single polymerization system to produce a wide range of materials with tuned reactivity and performance characteristics.
Solution Approach 2:
The patent allows variation of monomer composition, ratio, and types to change the physical and chemical parameters of the resulting polymer. By adjusting the amounts and types of hydroxyl-bearing and (meth)acrylate-bearing monomers, the reactivity, glass transition temperature, and other properties can be fine-tuned for specific applications.
3Reliability
If acrylic polymers are used as main backbone for radiation curable compositions, then good optical properties, adhesion, and outdoor resistance are achieved, but the polymer does not contain ethylenically unsaturated functionality and does not participate in crosslinking network after radiation curing
Solution Approach 1:
The patent merges the advantages of acrylic polymers (optical properties, adhesion) with ethylenically unsaturated functionality by incorporating monomers that contain both acrylic backbone structures and polymerizable double bonds. This combination allows the polymer to participate in crosslinking networks through radiation curing while maintaining the desirable optical and adhesive properties of acrylic polymers.
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 GMA-free, water-insoluble radiation curable composition with low tackiness before curing, enabling fine-tuning of properties for diverse applications like dual cure systems, post-formable films, and conformal coatings, while ensuring safety and environmental sustainability.
Implementation Method 1
an isocyanate group-containing monoadduct (MA) comprising at least one (meth)acrylate group and which attaches to the water-insoluble (meth)acrylic polymer (AP) comprising pendant hydroxyl groups by an urethane linkage
Data Source
AI summary
The present invention generally relates to the field of radiation curable compositions comprising (meth)acrylated acrylic polymers comprising pendant hydroxyl groups, methods for making these radiation curable compositions and their uses.In particular, the present invention refers to a radiation curable composition (X) comprising at least one (meth)acrylated acrylic polymer (AA) comprising pendant hydroxyl groups which is the reaction product of: a) At least one water-insoluble(meth)acrylic polymer (AP) comprising pendant hydroxyl groups which is the reaction product of: a1) at least one hydroxy functional ethylenically unsaturated monomer (AP1), and a2)at least one ethylenically unsaturated monomer (AP2) which is different from (AP1), and b) At least one isocyanate group-containing monoadduct (MA) comprising at least one (meth)acrylate group and which attaches to the water-insoluble(meth)acrylic polymer (AP) comprising pendant hydroxyl groups by an urethane linkage and which is the reaction product of: b1) at least one polyisocyanate (MA1), and b2) at least one hydroxy functional (meth)acrylate monomer (MA2), wherein the equivalent ratio of NCO groups to OH groups of the radiation curable composition (X) is from 1:0,5 to 1:10 and the glass transition temperature (Tg) of the radiation curable composition (X) after the acrylation is at least 10°C.