Single-Component Epoxy Adhesive for LED Packaging
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Solution Overview
Problem
Existing epoxy resin adhesives used in the electronic industry suffer from poor aging resistance, yellowing under UV radiation, and loss of transparency due to the addition of fillers for oxidation resistance, making them unsuitable for applications requiring both oxidation resistance and transparency, such as LED packaging.
Innovation Solution
A single-component epoxy adhesive composition comprising 42-67 wt% of an epoxy resin without a benzene ring structure, 32-57 wt% of a polymercaptan, and 0.1-12 wt% of an initiator, which is uniformly mixed to achieve high light transmittance, long working time, good adhesion, and excellent weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ordinary epoxy resin is used, then adhesion and chemical stability are good, but aging resistance is poor and yellowing occurs under UV radiation
Solution Approach 1:
The patent changes the chemical structure parameter of the epoxy resin by using hydrogenated epoxy resin without benzene ring structures instead of ordinary epoxy resin. This structural modification eliminates the chromophores that cause yellowing under UV radiation while maintaining the adhesion and chemical stability properties of epoxy resin.
Solution Approach 2:
The patent creates a composite adhesive system by combining hydrogenated epoxy resin with polymercaptan and specific additives. This composite formulation achieves both UV resistance (preventing yellowing) and maintaining good adhesion, resolving the contradiction between aging resistance and yellowing resistance.
2Reliability
If filler is added to resist yellowing, then oxidation resistance is improved, but transparency is lost
Solution Approach 1:
The patent changes the chemical composition parameter by selecting hydrogenated epoxy resin with specific structural characteristics that inherently provide UV and oxidation resistance without requiring opaque fillers. This maintains the transparency parameter while achieving the desired reliability for yellowing and oxidation resistance.
3Strength
If epoxy resin with good adhesion is used, then bonding strength is high, but time available for construction is insufficient
Solution Approach 1:
The patent uses a latent initiator system that remains dormant during mixing and application, allowing extended working time. Upon curing initiation, the reaction accelerates to achieve full adhesion strength. This dynamic control of the curing process resolves the contradiction between maintaining high adhesion and providing sufficient construction time.
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 epoxy adhesive exhibits high light transmittance (≥95%) after curing, a long working time (more than 24 hours), strong adhesion (shear strength ≥5 MPa), and superior weather resistance (light transmittance ≥90% after 200 hours of UV exposure), making it suitable for electronic industrial assembly and LED packaging.
Implementation Method 1
0.1-12 wt % of an initiator
Implementation Method 2
after irradiation with 405 nm-wavelength UV LED at an illuminance of 5 W/cm2 for 200 h
Data Source
AI summary
The present invention provides a single-component epoxy adhesive composition and a preparation method thereof. The single-component epoxy adhesive composition comprises, based on the total weight thereof as 100 wt %: 42-67 wt % of an epoxy resin without a benzene ring structure; 32-57 wt % of a polymercaptan; and 0.1-12 wt % of an initiator. The single-component epoxy adhesive composition according to a technical solution of the invention has high light transmittance after curing, long time available for construction, good adhesion, and in particular good weather resistance (yellowing resistance), and is suitable for electronic industrial assembly, and especially for the assembly and sealing of electronic display devices.