Film Adhesive Composition for Optical Precutting and Clear Curing
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Solution Overview
Problem
Film adhesives used in imaging devices and electronic components face challenges in achieving high transparency and strong adhesive strength, as light transmittance adjusting components like pigments impair transparency and adhesive strength when blended, making it difficult to accurately precut and bond transparent protective films.
Innovation Solution
A film adhesive composition comprising epoxy resin, epoxy resin curing agent, and phenoxy resin, where the curing agent is dispersed as fine particles with a specific particle diameter, controlling light transmittance before and after curing to enable accurate precutting and high transparency with strong adhesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light transmittance adjusting component such as a pigment is blended in a film adhesive to lower the transparency, then the position and shape sensing by an optical sensor becomes possible, but the transparency remains impaired even after curing and adhesive strength decreases
Solution Approach 1:
The patent changes the physical state of the curing agent from liquid to powder form with specific particle size (d90: 20.0 μm or less). This parameter change allows the curing agent to scatter light in the uncured film adhesive, enabling optical sensor detection, while the fine particles are completely consumed during thermal curing, restoring transparency and maintaining adhesive strength in the cured product.
Solution Approach 2:
The patent applies different properties to different states of the film adhesive: in the uncured state, the film contains dispersed powder curing agent particles that provide light scattering for sensing; in the cured state, these particles have reacted and disappeared, leaving a transparent, high-strength adhesive. This local quality differentiation resolves the contradiction between sensing requirements and optical performance.
2Measurement precision
If a light transmittance adjusting component such as a pigment is blended in a film adhesive, then the position and shape sensing by an optical sensor becomes possible, but the transparency remains impaired even after curing
Solution Approach 1:
The patent uses parameter change by transforming the curing agent into powder form with controlled particle size. The powder particles provide sufficient light scattering for optical sensing in the uncured state, while being completely consumed during thermal curing, thereby restoring light transmittance in the final cured product.
Solution Approach 2:
The patent extracts the light scattering function from permanent pigments and assigns it temporarily to powder curing agent particles. These particles serve their dual purpose of enabling sensing and then being consumed during curing, effectively removing the scattering components after they have served their function, thus restoring transparency.
3Manufacturing precision
If the film adhesive is precut using optical sensor sensing, then high-accuracy precut processing is achieved, but the sensing is difficult when the film adhesive is transparent
Solution Approach 1:
The patent changes the physical form of the curing agent to powder with specific particle size distribution (d90: 20.0 μm or less). This parameter change creates sufficient light scattering in the uncured film adhesive, enabling optical sensors to detect the film's position and shape for high-precision precutting, while ensuring the particles are completely consumed during curing.
4Strength
If the content of epoxy resin curing agent is increased to improve adhesive strength, then strong adhesive strength is achieved, but light transmittance before curing increases making precutting sensing difficult
Solution Approach 1:
The patent changes the curing agent from liquid to powder form with controlled particle size. This allows using higher concentrations of curing agent (0.30 to 12.0 mass %) to achieve strong adhesive strength while the powder particles provide light scattering for optical sensing, resolving the trade-off between strength and detectability.
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 film adhesive allows for high-accuracy precutting and exhibits high transparency and strong adhesive strength after thermal curing, enhancing optical characteristics and adhesion reliability.
Implementation Method 1
a light transmittance T1 of the film adhesive at a wavelength of 400 nm is 90% or less
Implementation Method 2
a cured product obtained by thermally curing the film adhesive
Implementation Method 3
an epoxy resin curing agent (B)
Data Source
AI summary
A film adhesive containing: an epoxy resin (A); an epoxy resin curing agent (B); and a phenoxy resin (C),wherein a content of the epoxy resin curing agent (B) in the film adhesive is 0.30 to 12.0 mass %; andwherein a light transmittance T1 of the film adhesive at a wavelength of 400 nm is 90% or less, a light transmittance T2 of a cured product obtained by thermally curing the film adhesive at a wavelength of 400 nm is 85% or more, and T1<T2 is satisfied.