Polymer Substrate Hardcoat Layer PE-CVD Gradient Structure
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Solution Overview
Problem
Current polymer substrates with hard coating layers, such as those used in automobile windows, lack sufficient abrasion resistance and heat resistance, leading to issues like peeling and cracking, especially when exposed to harsh environmental conditions like high humidity and temperature variations.
Innovation Solution
A polymer substrate with a hard coating layer is developed by laminating a silicon oxide film using plasma-enhanced chemical vapor deposition (PE-CVD), where the film thickness, nano indentation depth, and critical compression ratio are optimized, and surface treatment is applied to enhance adhesive strength between the silicon oxide layer and the substrate, using a cured underlayer composed of multifunctional acrylate and inorganic oxide fine particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high hardness hard coating layer is formed by PE-CVD on a polymer substrate, then abrasion resistance is improved, but interface stress increases causing peeling and cracking
Solution Approach 1:
The patent applies parameter changes by controlling the deposition rate during PE-CVD to form a gradient structure in the hard coating layer. The deposition rate is varied spatially to create zones with different densities and stress characteristics, allowing the outer region to provide high abrasion resistance while the inner region near the substrate provides stress relief and strong adhesion, thereby preventing peeling and cracking
Solution Approach 2:
The patent creates a composite structure combining the polymer substrate with a gradient hard coating layer formed by PE-CVD. This composite material system integrates the benefits of both components: the polymer substrate provides flexibility and base properties, while the gradient hard coating layer provides enhanced abrasion resistance without compromising adhesion, achieving a balance between hardness and durability
2Strength
If the hard coating layer thickness is increased to improve abrasion resistance, then surface hardness is improved, but heat resistance and resistance to thermal stress deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the deposition rate profile during PE-CVD to control both the thickness and internal structure of the hard coating layer. By varying the deposition rate spatially, the patent achieves an optimal thickness distribution that provides sufficient surface hardness while maintaining adequate heat resistance and thermal stress resistance, preventing cracking under thermal conditions
3Ease of manufacture
If conventional PE-CVD is used to form a hard coating layer, then manufacturing process is simple, but environmental resistance (boiling water test and heat resistance test) is inadequate
Solution Approach 1:
The patent applies parameter changes by modifying the PE-CVD process parameters, specifically the deposition rate profile, to create a gradient structure that enhances environmental resistance. This modified PE-CVD process maintains relative simplicity while achieving superior performance in boiling water tests and heat resistance tests by forming a coating layer with optimized internal stress distribution and adhesion characteristics
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 resulting polymer substrate demonstrates superior abrasion resistance and heat resistance, comparable to inorganic glass, ensuring long-term reliability and durability even in harsh environments, making it suitable for applications like automobile windows.
Implementation Method 1
laminating a silicon oxide film using plasma-enhanced chemical vapor deposition (PE-CVD)
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
The present invention provides a polymer substrate with a hardcoat layer exhibiting excellent environmental resistance and wear resistance. A polymer substrate (60) is 1-20mm thick and a hardcoat layer (70, 80) on the surface thereof comprises: an underlayer cured layer (70) with a thickness of 1-20µm, and including 10-90 parts by weight of a multifunctional acrylate, and 90-10 parts by weight of inorganic oxide fine particles and/or a silicon compound hydrolytic condensate; and a silicon oxide layer (80) which is in direct contract with the underlayer cured layer, is formed by PE-CVD with an organosilicon compound as the starter material, and satisfies all of the following conditions (a)-(c): (a) the film thickness of the silicon oxide layer is 3.5-9.0µm; (b) the maximum indentation depth of the surface of the silicon oxide layer by nanoindentation measurement at a maximum load of 1mN is 150nm or less; and (c) the limit compression ratio K of the silicon oxide layer is at most 0.975 in a 3-point bending test of the polymer substrate with a hardcoat layer having been subjected to indentation deformation that causes the surface on which the silicon oxide layer is layered to be indented.