Active Energy Ray-Curable Coating Composition for Mar Resistance and Weatherability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Synthetic resin molded articles, such as those used in automotive components, face challenges with insufficient mar resistance and weatherability, particularly when exposed to ultraviolet rays, leading to yellowing and cracking over time.
Innovation Solution
A coating composition is developed that includes a caprolactone-modified specific urethane(meth)acrylate and other specific components, which, when irradiated with active energy rays, forms a cured film that enhances mar resistance and weatherability, suppressing crack generation and improving durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating material composed of silicone based or melamine based resin composition is coated and heated to form a crosslinked coating film, then mar resistance is improved, but weatherability deteriorates due to yellowing and cracking under ultraviolet exposure
Solution Approach 1:
The patent uses a composite coating system combining silane-modified polyurethane resin (providing mar resistance through crosslinking) with weather-resistant components including acrylic resins and UV stabilizers. This composite approach allows the coating to simultaneously achieve high mar resistance through silane crosslinking and excellent weatherability through UV-absorbing and HALS components that prevent yellowing and degradation.
2Weight of moving object
If polycarbonate resin molded articles are used for automotive materials, then lightweight and design diversification are achieved, but weatherability deteriorates as they are easily deteriorated by ultraviolet rays causing yellowing and cracks
Solution Approach 1:
The patent applies a pre-formulated coating composition containing UV absorbers and HALS (hindered amine light stabilizers) before the polycarbonate resin is exposed to ultraviolet degradation. This preliminary protective layer prevents UV-induced yellowing and cracking by absorbing harmful radiation and scavenging free radicals, thereby preserving the weatherability of the lightweight polycarbonate automotive components.
3Reliability
If conventional resin compositions are used to improve weatherability, then ultraviolet resistance is enhanced, but mar resistance becomes insufficient
Solution Approach 1:
The patent merges two previously separate functional systems into one unified coating: the silane-modified polyurethane resin system (providing mar resistance through crosslinking) and the weather-resistant acrylic resin system (providing UV protection). The silane groups crosslink to form a hard, scratch-resistant network while the acrylic components and added UV stabilizers maintain weatherability, achieving both high mar resistance and excellent weatherability simultaneously.
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 excellent mar resistance, weatherability, heat resistance, chemical resistance, and adhesion to the base material, maintaining performance even after prolonged outdoor exposure.
Implementation Method 1
a coating material composed of a silicone based or melamine based resin composition is coated on a surface of a synthetic resin molded article and subjected to heating condensation to form a crosslinked coating film, and hence mar resistance is improved and a method in which a resin composition composed of a radical polymerizable monomer is coated on a surface of a synthetic resin molded article and an active energy ray is irradiated on the resultant surface to form a crosslinked coating film
Implementation Method 2
a resin composition obtained by compounding substances such as a poly(meth)acrylate of a mono- or poly-pentaerythritol, a urethane poly(meth)acrylate compound having at least 2 radical-polymerizable unsaturated double bonds in a molecule, and a poly[(meth)acryloyloxyalkyl](iso)cyanurate in a specific proportion is proposed, and it is found that this resin composition can realize a compatibility of excellent mar resistance and weatherability
Data Source
AI summary
Disclosed is an active energy ray-curable coating composition containing (A) 10 to 70% by mass of a poly(meth)acrylate of a mono- or polypentaerythritol; (B) 5 to 50% by mass of (B-1) a polyester type aliphatic urethanedi(meth)acrylate compound which is obtained by reacting an aliphatic isocyanate compound, a caprolactone-modified polyester diol, and an acrylate having a hydroxyl group, (B-2) a compound represented by formula (2), or (B-3) a polyether type urethane di(meth)acrylate compound having two (meth)acryloyloxy groups in a molecule, wherein, in the case that component (B) is component (B-3), component (A) contains at least one caprolactone-modified (meth)acryloyloxy group; (C) 5 to 70% by mass of a poly[(meth)acryloyloxyalkyl](iso)cyanurate represented by formula (3) or (4); and (D) 0.1 to 10% by mass of a photopolymerization initiator. The active energy ray-curable coating composition can form a cured film excellent in weatherability, mar resistance, and adhesion to a base material.