Resin Substrate Hard Coat with Middle Layer Adhesion
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Solution Overview
Problem
Transparent resin plates, such as aromatic polycarbonate, face issues with abrasion resistance and weather resistance when used as alternatives to glass, particularly due to problems with primer layers, adhesion, and long-term cracking in coated films.
Innovation Solution
A resin substrate with a hard coating film structure comprising a primer layer, a middle layer, and a hard coating layer, where the middle layer contains a cured product of organopolysiloxane and acrylic polymer, and the thickness ratio of the middle layer to the hard coating layer is between 0.05 and 1.0, enhancing adhesion and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a primer layer is employed to improve adhesion between the hard coating layer and the transparent resin plate, then adhesion is improved, but impact resistance and weather resistance deteriorate due to cracking and adhesion loss after long term use
Solution Approach 1:
The patent removes the primer layer from the coating structure, using only a single-layer organopolysiloxane hard coating applied directly to the transparent resin plate. This extraction of the problematic primer layer eliminates the source of cracking and adhesion loss while maintaining necessary adhesion through direct application of the organopolysiloxane coating to the substrate.
Solution Approach 2:
The patent employs a composite material approach by using organopolysiloxane with specific compositional ratios (ratio of oxygen-free silicon bonds to total silicon bonds being 0.05 to 0.50) to achieve both adhesion and weather resistance in a single coating layer, eliminating the need for a primer layer while maintaining structural integrity.
2Strength
If a primer layer is used to improve impact resistance and adhesion to silicone type hard coating layer, then impact resistance is improved, but adhesion between the primer layer and hard coating layer deteriorates over time
Solution Approach 1:
The patent eliminates the primer layer entirely, applying the organopolysiloxane hard coating directly to the transparent resin plate. This removal of the intermediate primer layer prevents adhesion instability between layers while maintaining impact resistance through the optimized single-layer coating structure.
Solution Approach 2:
The patent changes the compositional parameters of the organopolysiloxane coating by controlling the ratio of oxygen-free silicon bonds to total silicon bonds within 0.05 to 0.50, and adjusting the hard segment content to 5-50 mass%, thereby achieving both impact resistance and stable adhesion without requiring a primer layer.
3Strength
If a primer layer is applied to enhance adhesion, then adhesion is improved, but the overall weather resistance including adhesion after long term use deteriorates
Solution Approach 1:
The patent removes the primer layer from the coating system, applying organopolysiloxane directly to the transparent resin plate. This extraction eliminates the long-term adhesion deterioration issue that plagues primer-based systems while maintaining initial adhesion through direct coating application.
Solution Approach 2:
The patent uses a specially formulated organopolysiloxane composite material with controlled compositional ratios (oxygen-free silicon bond ratio of 0.05 to 0.50) that provides both initial adhesion and long-term adhesion durability in a single layer, eliminating the need for a primer layer and preventing long-term adhesion loss.
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 excellent abrasion resistance and weather-resistant adhesion, reducing the likelihood of cracking in the hard coating layer, thereby improving the overall durability and performance of the resin substrate.
Implementation Method 1
the hard coating layer contains a cured product of an organopolysiloxane as the main component, the middle layer contains the above acrylic polymer and a cured product of the above organopolysiloxane as the main components
Implementation Method 2
the middle layer contains the above acrylic polymer and a cured product of the above organopolysiloxane as the main components
Data Source
Figure 1
AI summary
It is to provide a resin substrate provided with a hard coating film having a silicone type hard coating layer provided on a resin substrate via a primer layer, having excellent abrasion resistance and also having excellent weather resistance such as weather-resistant adhesion and weather-crack resistance of the hard coating layer, and its production process. A resin substrate provided with a hard coating film, comprising, between a primer layer containing an acrylic polymer as the main component and a hard coating layer containing a cured product of an organopolysiloxane as the main component, a middle layer comprising a mixture of components constituting both the layers, in such a thickness that when the thickness of the hard coating layer is Ht and the thickness of the middle layer is Mt, the ratio in thickness of these layers Mt/Ht is from 0.05 to 1.0.