Photovoltaic Sheet Adhesive Composition for UV Yellowing Resistance
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Solution Overview
Problem
Existing adhesives used in photovoltaic sheets suffer from yellowing issues due to photo-oxidation under UV irradiation, compromising transparency and efficiency, despite the need for aromatic structures for strong adhesion.
Innovation Solution
An adhesive composition comprising a resin component with a polyester polyol, hydrogenated epoxy, and silane, and a hardener component with aliphatic or alicyclic polyisocyanate, free of aromatic rings, to achieve strong adhesion and resistance to yellowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aromatic structures are used in adhesive to improve adhesion, then adhesion strength is improved, but yellowing resistance deteriorates under UV irradiation
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive by using aliphatic and alicyclic polyols instead of aromatic polyols, and by incorporating specific additives (HALS, UV absorbers, hindered phenols) to modify the adhesive's resistance to photo-oxidation while maintaining adhesion performance
Solution Approach 2:
The invention creates a composite adhesive system combining multiple components: aliphatic/alicyclic polyol, polyisocyanate, hydrogenated epoxy resin, silane, and multiple additives (HALS, UV absorbers, hindered phenols) that work synergistically to provide both strong adhesion and excellent yellowing resistance
2Object-affected harmful factors
If transparency is improved by removing aromatic structures, then yellowing resistance is improved, but adhesion strength deteriorates
Solution Approach 1:
The invention changes the chemical structure parameters by selecting aliphatic and alicyclic polyols with specific molecular weights and glass transition temperatures, and by optimizing the ratios of different components to achieve both transparency/yellowing resistance and adhesion strength
Solution Approach 2:
The invention introduces intermediary substances (silane, hydrogenated epoxy resin, and various additives) that mediate between the polyol and substrate, providing adhesion enhancement without requiring aromatic structures, thus maintaining transparency and yellowing resistance
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 adhesive composition maintains high adhesion and prevents yellowing, ensuring long-term transparency and efficiency in outdoor applications, particularly in photovoltaic sheets.
Implementation Method 1
Yellowing is caused by photo-oxidation or photo-degradation of polymers under ultraviolet (UV) irradiation
Implementation Method 2
Yellowing is caused by photo-oxidation or photo-degradation of polymers under ultraviolet (UV) irradiation
Data Source
AI summary
An adhesive composition which comprises a resin component (A) comprising a polyester polyol, a hydrogenated epoxy, a silane, and an optional organic solvent; and a hardener component (B) comprising an aliphatic polyisocyanate and/or an alicyclic polyisocyanate; the adhesive composition being substantially free of aromatic rings. The polyester polyol is prepared by reacting a poly basic acid and a polyalcohol, and the polybasic acid comprises an aliphatic polybasic acid and/or an alicyclic polybasic acid. The polyester polyol has a glass transition temperature (Tg) in a range of from 0° C. to 10° C. The adhesive composition of the present invention has strong adhesion, excellent weather-resistance and yellowing-resistance.