Optical Silicone Assembly Adhesion via Buffer Layer
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Solution Overview
Problem
Optical silicone products face challenges in adhering to various substrates without compromising mold release properties, as existing moldable silicone compositions exhibit poor adhesion due to their non-adhesive nature, especially when interacting with metal molds.
Innovation Solution
A method involving the use of an optically clear silicone adhesive composition to form a buffer layer between the optical silicone composition and substrates, which includes treating the substrate with the adhesive composition, followed by injecting or overmolding the silicone composition and heating it to form a strong adhesive bond without affecting mold release properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If moldable silicone composition is used for its mold release property, then ease of manufacture is improved, but adhesion to substrate deteriorates
Solution Approach 1:
The invention divides the silicone assembly into two distinct segments: a moldable silicone composition for the optical product that ensures easy mold release, and a separate silicone adhesive composition applied as a buffer layer that provides strong substrate adhesion. This segmentation allows each material to perform its specialized function without compromise.
Solution Approach 2:
The silicone adhesive composition acts as an intermediary buffer layer between the moldable silicone composition and the substrate. This intermediate layer mediates the conflicting requirements by providing the adhesion function that the moldable silicone lacks, while allowing the moldable silicone to maintain its mold release properties.
2Strength
If adhesion promoter is added to improve adhesion, then adhesion to substrate is improved, but optical clarity deteriorates
Solution Approach 1:
The silicone adhesive composition serves as an intermediary layer that inherently provides adhesion promotion through its chemical composition and bonding mechanisms, eliminating the need for additional adhesion promoters in the optical silicone product. This buffer layer approach maintains optical clarity while achieving strong adhesion.
Solution Approach 2:
The invention changes the adhesion mechanism by using a specifically formulated silicone adhesive composition with controlled crosslinking density and chemical composition. By adjusting parameters such as the ratio of silane-modified polysiloxane to hydrogen-containing polysiloxane, and controlling moisture content, strong adhesion is achieved without compromising optical properties.
3Strength
If silicone adhesive composition is applied to substrate, then adhesion to substrate is improved, but mold release property deteriorates
Solution Approach 1:
The invention segments the adhesive function from the moldable silicone composition by applying a separate silicone adhesive composition to the substrate first. This allows the moldable silicone composition to remain free of adhesion promoters, maintaining its mold release properties, while the dedicated adhesive layer provides the necessary bonding strength.
Solution Approach 2:
The silicone adhesive composition is applied to the substrate in advance (preliminary action) before the moldable silicone composition is injected or overmolded. This preliminary application ensures that adhesion is established at the substrate interface without interfering with the subsequent mold release of the optical silicone product.
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 method enables optical silicone assemblies to adhere effectively to diverse substrates, including thermoplastics, glass, and metals, while maintaining the mold release properties, ensuring strong adhesion without compromising the optical clarity and mechanical integrity of the silicone products.
Implementation Method 1
an optically clear silicone adhesive composition can form a buffer layer for developing adhesion between the optical moldable silicone composition and the substrates
Implementation Method 2
heating the optically clear moldable silicone composition to form the optical silicone assembly
Data Source
AI summary
A method for producing an optical silicone assembly is disclosed. The method comprises the steps of: i) treating a surface of a substrate with an optically clear silicone adhesive composition; ii) placing the substrate obtained by step i) into a mold; iii-a) injecting an optically clear moldable silicone composition into the mold, and/or iii-b) overmolding the optically clear moldable silicone composition onto the substrate; and then iv) heating the optically clear moldable silicone composition to form the optical silicone assembly. The optical silicone assembly produced by the method of this disclosure is characterized by excellent adhesion of an optical silicone product to various types of substrates.