Radiation-Curable Coating Composition for Deformable Films
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Solution Overview
Problem
Current radiation-curing coatings face challenges in achieving high abrasion resistance, scratch resistance, and solvent resistance while maintaining deformability and economic viability, with existing macromonomers requiring special synthetic production and lacking sufficient blocking resistance for rolling and deformation processes.
Innovation Solution
A coating composition comprising at least 30% by weight of a thermoplastic polymer with a molecular weight of at least 100,000 g/mol, a UV-curable reactive diluent, a photoinitiator, and ethylenically unsaturated groups, which provides good blocking resistance, solvent resistance, and scratch resistance after curing, and can be efficiently produced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high crosslinking density is used in the coating, then abrasion resistance and scratch resistance are improved, but elongation decreases and the coating becomes prone to cracking during forming
Solution Approach 1:
The patent applies parameter changes by carefully controlling the double bond density within a specific range (2-6 mol/kg, preferably 3-5 mol/kg) and adjusting the molecular weight of the thermoplastic polymer (≥100,000 g/mol). These parameter optimizations enable the coating to achieve sufficient crosslinking density for abrasion and scratch resistance while maintaining adequate elongation (≥5%) to prevent cracking during forming operations.
2Strength
If special macromonomers are used to achieve high resistance properties, then abrasion resistance and solvent resistance are improved, but manufacturing complexity and costs increase
Solution Approach 1:
The patent employs composite materials by combining conventional thermoplastic polymers (such as polyesters, polyacrylates, or polyurethanes) with reactive diluents containing ethylenically unsaturated groups. This composite approach achieves high solvent resistance and abrasion resistance through radiation-induced crosslinking without requiring specially synthesized macromonomers, thereby simplifying manufacturing and reducing costs while maintaining performance.
3Strength
If the coating is fully cured before deformation, then protective layer properties are improved, but blocking resistance decreases and the coating cannot be rolled or deformed
Solution Approach 1:
The patent applies preliminary action by performing radiation curing after the forming process rather than before. The coating is applied and dried to a tack-free state, then the substrate is deformed or formed, and finally the coating is cured by radiation exposure. This sequence ensures the coating maintains flexibility during forming while achieving high scratch resistance and protective properties in the final product.
4Ease of operation
If thermoplastic polymers with low molecular weight are used, then ease of application is improved, but blocking resistance and mechanical properties deteriorate
Solution Approach 1:
The patent applies parameter changes by specifying a minimum molecular weight of 100,000 g/mol for the thermoplastic polymer. This parameter optimization ensures the polymer has sufficient viscosity and blocking resistance for economical roll coating applications while maintaining adequate deformability during forming. The molecular weight range balances application ease with mechanical performance.
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 coating composition achieves high resistance to abrasion, scratches, and solvents while allowing for deformation and economic production, enabling the use of coated films in complex molding processes without compromising blocking resistance or increasing production costs.
Implementation Method 1
A radiation-curable coating composition comprising at least one thermoplastic polymer, a reactive diluent, a photoinitiator... A radiation-induced crosslinking reaction in the coating is particularly suitable for post-curing.
Data Source
AI summary
The present invention relates to a coating composition comprising (a) at least one thermoplastic polymer having a mean molar mass Mw of at least 100 000 g/mol in a content of at least 30% by weight of the solids content of the coating composition, (b) at least one UV-curable reactive diluent in a content of at least 30% by weight of the solids content of the coating composition, (c) at least one photoinitiator in a content of ≥ 0.1 to ≤ 10 parts by weight of the solids content of the coating composition, and (d) at least one organic solvent, where the proportion of ethylenically unsaturated groups is at least 3 mol per kg of the solids content of the coating composition. It further relates to a process for producing such coating compositions, to films coated therewith, to the use of such films for production of shaped bodies, to a process for producing shaped bodies having a radiation-cured coating, and to shaped bodies producible by this process. The inventive coatings have excellent solvent stability, and good scratch resistance and pencil hardness.