Photocurable Sheet Adhesive for Curved Plastic Bonding
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Solution Overview
Problem
Conventional photocurable compositions used for bonding objects to curved adherends often experience peeling issues due to springback and shape changes, especially when the adherend is plastic or difficult to adhere to.
Innovation Solution
A photocurable composition comprising a urethane-modified (meth)acrylate oligomer synthesized from a polyol, a polyisocyanate compound, and a (meth)acrylate with a hydroxy group, along with a photoinitiator, which exhibits tackiness before curing and maintains adhesion after curing, allowing it to follow shape changes in curved adherends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a tackiness agent is used to bond objects to curved adherends, then adhesion is improved, but the tackiness agent is peeled off due to springback and shape changes of the adherend
Solution Approach 1:
The invention changes the physical and chemical parameters of the adhesive composition by incorporating specific components (polyol with formula 1, polyisocyanate compound, (meth)acrylate with hydroxy group) in controlled ratios. This creates a composition that maintains tackiness while gaining elasticity, allowing it to accommodate adherend shape changes without peeling
Solution Approach 2:
The invention uses a composite adhesive system combining multiple chemical components (polyol, polyisocyanate, (meth)acrylate, photoinitiator) that work synergistically. The polyol provides backbone flexibility, the polyisocyanate creates crosslinked urethane bonds for strength, and the (meth)acrylate adds curability and adhesion, creating a material that simultaneously achieves tackiness and resistance to peeling
2Strength
If conventional adhesives are used on plastic adherends, then bonding is attempted, but the adhesives are easily peeled due to the inherent properties of plastic materials
Solution Approach 1:
The invention modifies the adhesive's chemical composition parameters to include specific functional groups (hydroxy groups in (meth)acrylate, isocyanate groups in polyisocyanate) that can form strong bonds with plastic surfaces. The controlled molecular weight and structure of the polyol component allow the adhesive to adapt to the surface properties of plastic adherends
Solution Approach 2:
The polyol component acts as an intermediary between the rigid crosslinked network (from polyisocyanate and (meth)acrylate) and the plastic adherend surface. Its flexible polyether or polyester backbone structure allows it to bridge the interface between the adhesive system and the plastic substrate, improving wetting and bonding while accommodating surface irregularities
3Adaptability or versatility
If the adherend shape changes easily, then bonding flexibility is needed, but the tackiness agent is more easily peeled off
Solution Approach 1:
The invention creates a dynamic adhesive system that can transition between tacky (uncured) and rigid (cured) states. Before curing, the composition remains soft and tacky to follow adherend shape changes. After photocuring, it transforms into a crosslinked network that maintains the bonded shape while providing strength, effectively adapting to shape changes without peeling
Solution Approach 2:
The invention changes the rheological and mechanical parameters of the adhesive through controlled composition. The polyol provides initial flexibility and tackiness, while the photoinitiator enables transformation to a rigid crosslinked structure. This parameter transformation allows the adhesive to first adapt to shape changes, then lock in the bonded configuration with strength
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 composition effectively adheres to curved surfaces before and after curing, maintaining stability and ensuring strong bonding even with materials that are hard to adhere to, such as plastics, while preventing peeling due to shape changes.
Implementation Method 1
the component (B) is a photoinitiator
Data Source
AI summary
The present invention relates to a photocurable composition having a sheet shape at 25° C. in an uncured state, the photocurable composition including a urethane-modified (meth)acrylate oligomer and a photoinitiator and being free from a film-forming component. The present invention also relates to a photocurable composition, a method for producing a photocurable composition having a sheet shape at 25° C. in an uncured state, and a laminated body.