Insert Molding Laminate Adhesive Layering for Touch Sensors
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Solution Overview
Problem
The existing methods for insert molding face challenges with adhesives that have poor adhesiveness to both glass and plastic films, and are not suitable for transparent display windows, leading to poor attachment of capacitance-type touch sensors and potential foaming due to heat from molten resin.
Innovation Solution
An insert molding process involving a glass substrate with a heat-resistant adhesive layer and a transparent pressure-sensitive adhesive layer, where the heat-resistant adhesive layer resists heat from the molten resin and prevents foaming, while the transparent adhesive ensures strong adhesion to both the glass and the touch sensor, maintaining transparency and clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent pressure-sensitive adhesive is used to attach the capacitance-type touch sensor, then adhesiveness to both glass and plastic film is improved and transparency is maintained, but heat resistance deteriorates and foaming occurs due to heat from molten molding resin
Solution Approach 1:
The adhesive system is divided into two separate layers: a heat-resisting adhesive layer (first adhesive layer) that provides thermal stability and prevents foaming, and a transparent pressure-sensitive adhesive layer (second adhesive layer) that provides strong adhesion and transparency. This segmentation allows each layer to specialize in one function, resolving the contradiction between adhesion and heat resistance.
Solution Approach 2:
The invention uses a composite adhesive structure combining two different adhesive materials with complementary properties. The heat-resisting adhesive layer uses materials with high thermal stability, while the transparent pressure-sensitive adhesive layer uses materials optimized for adhesion and optical clarity. This composite approach allows the system to achieve both strong adhesion and heat resistance simultaneously.
2Reliability
If adhesive for glass is used to attach the capacitance-type touch sensor, then attachment is achieved, but adhesiveness to plastic film is poor and transparency is insufficient for clear display windows
Solution Approach 1:
The adhesive system is divided into two separate layers: a heat-resisting adhesive layer (first adhesive layer) that provides thermal stability and prevents foaming, and a transparent pressure-sensitive adhesive layer (second adhesive layer) that provides strong adhesion and transparency. This segmentation allows each layer to specialize in one function, resolving the contradiction between adhesion and heat resistance.
Solution Approach 2:
Different regions of the adhesive system have different properties optimized for their specific functions. The first adhesive layer (heat-resisting) is positioned to provide thermal stability, while the second adhesive layer (transparent pressure-sensitive) is positioned to provide adhesion and optical clarity where needed. This local optimization resolves the contradiction between attachment strength and transparency.
3Device complexity
If a single adhesive layer is used, then the structure is simple, but it cannot simultaneously provide heat resistance, strong adhesion, and transparency
Solution Approach 1:
The adhesive system is divided into two separate layers: a heat-resisting adhesive layer (first adhesive layer) that provides thermal stability and prevents foaming, and a transparent pressure-sensitive adhesive layer (second adhesive layer) that provides strong adhesion and transparency. This segmentation allows each layer to specialize in one function, resolving the contradiction between adhesion and heat resistance.
Solution Approach 2:
The two-layer adhesive structure serves multiple functions simultaneously: the first layer provides heat resistance and foaming prevention, while the second layer provides strong adhesion and transparency. This multi-functional design allows a single adhesive system to accomplish tasks that would otherwise require multiple separate components.
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 adhesion and transparency, preventing foaming and ensuring the touch sensor remains firmly attached, even if the glass substrate breaks, with a manufacturing method that integrates a heat-resistant adhesive layer and a transparent pressure-sensitive adhesive layer to enhance the bonding process.
Implementation Method 1
the heat-resisting adhesive layer that resists heat from the molten injection-molding resin is formed on the glass substrate of the insert molding laminate, which prevents any foaming from developing due to the heat of the molten injection-molding resin
Implementation Method 2
the capacitance-type touch sensor is firmly adhered to the glass substrate through the transparent pressure-sensitive adhesive layer
Data Source
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AI summary
The invention provides an insert molding laminate providing excellent transparency to a transparent window portion and excellent adhesiveness to both a capacitance-type touch sensor and an injection-molded resin portion, and a manufacturing method thereof, and an insert molding and a manufacturing method thereof. The insert molding laminate comprises a glass substrate 2, a heat-resisting adhesive layer 4 having a frame shape and formed on peripheral portions of one surface of the glass substrate 2, a transparent pressure-sensitive adhesive layer 3 formed on an inner side portion of the one surface of the glass substrate 2 and shaped to partially overlap the heat-resisting adhesive layer 4 in a thickness direction of the glass substrate , and a capacitance-type touch sensor 5 laminated on the transparent pressure-sensitive adhesive layer 3 and having a configuration smaller than an outer configuration of the glass substrate 2.