Wavelength Conversion Film Primer for Humidity-Resistant Phosphor Adhesion
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Solution Overview
Problem
The existing wavelength conversion sheets experience peeling between the phosphor layer and the barrier film under high-temperature, high-humidity conditions, leading to degradation due to oxygen and water vapor invasion, which compromises the adhesion and longevity of the phosphor layer.
Innovation Solution
A film with a primer layer composed of a polyurethane-based resin with a softening point of 250° C. or higher, a mole ratio of isocyanate groups to hydroxyl groups (NCO/OH) of 1.1 or more, and the inclusion of a silane coupling agent, which enhances the adhesion to the phosphor layer and provides a barrier against environmental degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyurethane-based resin composition is used as a primer layer to improve close adhesion to the phosphor layer, then adhesion is improved, but the resin degrades under high-temperature, high-humidity conditions causing peeling
Solution Approach 1:
The patent changes the key parameter of the polyurethane-based resin composition by specifying a softening point of 250°C or higher and an NCO/OH ratio of 1.1 or more. These parameter changes ensure the resin maintains its adhesive properties while resisting degradation under high-temperature, high-humidity conditions, thus resolving the contradiction between initial adhesion strength and long-term adhesion stability.
Solution Approach 2:
The patent creates a composite primer layer system combining a polyurethane-based resin with specific molecular weight ranges (1,000-100,000) and controlled crosslinking density through the NCO/OH ratio. This composite approach allows the material to simultaneously achieve strong initial adhesion and enhanced resistance to environmental degradation, preventing peeling under harsh conditions.
2Temperature
If the primer layer softening point is increased to 250°C or higher to prevent degradation, then thermal stability is improved, but the resin composition becomes more complex
Solution Approach 1:
The patent achieves high thermal stability by changing the softening point parameter to 250°C or higher through selective resin composition. This is accomplished by using polyols with specific molecular weights (1,000-100,000) and controlling the isocyanate to hydroxyl ratio, which simplifies the formulation approach while meeting the thermal stability requirement.
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 ensures excellent close adhesion to the phosphor layer even after extended exposure to high-temperature, high-humidity environments, effectively preventing degradation and maintaining the integrity of the phosphor layer.
Implementation Method 1
a primer layer on the base material, wherein the primer layer comprises a cured product of a resin composition comprising a polyurethane-based resin
Implementation Method 2
the inclusion of a silane coupling agent, which enhances the adhesion to the phosphor layer
Data Source
AI summary
Provided are: a film for a wavelength conversion sheet having superior close adhesion to a phosphor layer when used for a wavelength conversion sheet, a wavelength conversion sheet having the film; and a backlight and a display device having the wavelength conversion sheet. A film (10) for a wavelength conversion sheet having: a base material (20); and a primer layer (30) on the base material (20), wherein the primer layer (30) includes a cured product of a resin composition including a polyurethane-based resin, and the cured product has a softening point of 250° C. or higher.