Dual-Curable Pressure Sensitive Adhesive Tape
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Solution Overview
Problem
Current pressure-sensitive adhesive tapes lack strong and permanent adhesion, especially when exposed to outdoor conditions and heavy loads, due to their reliance on physical connections rather than chemical reactions, and dual-curable adhesives require additional energy for complete curing, reducing user-friendliness.
Innovation Solution
A dual-curable adhesive composition that is UV-curable and moisture-curable, with a specific ratio of components allowing sequential curing, providing strong immediate adhesion and permanent bonding without the need for additional energy, forming an adhesive tape with pressure-sensitive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pressure-sensitive adhesive tapes use physical connections (physisorption) for bonding, then immediate tack is high and objects can be mounted immediately, but adhesion strength is less strong and often less permanent, making the tape unsuitable for heavy objects or outdoor applications
Solution Approach 1:
The patent combines two different bonding mechanisms into a single adhesive system: physical connections (physisorption) for immediate tack and chemical reactions (chemisorption) for permanent strength. The adhesive composition includes both polar groups for physical adsorption and reactive groups for chemical bonding, allowing the tape to provide both immediate mounting capability and long-term durability.
Solution Approach 2:
The adhesive layer is formulated as a composite material containing polymer matrix with both polar functional groups (for physisorption) and reactive functional groups (for chemisorption). This composite structure enables the adhesive to exhibit dual bonding characteristics, combining the advantages of pressure-sensitive bonding with the strength of chemical bonding.
2Strength
If liquid adhesives use chemical reaction (chemisorption) to bond objects, then adhesion strength is very high and can survive outdoor conditions, but immediate tack is limited and the adhesive needs curing time
Solution Approach 1:
The patent merges chemisorption-based liquid adhesives with PSA characteristics by incorporating polar groups that provide immediate physical adsorption. This allows the adhesive to exhibit both chemical bonding strength and pressure-sensitive tack, eliminating the need for secondary fixation mechanisms while maintaining high adhesion strength.
Solution Approach 2:
The adhesive composition is designed with specific functional group ratios and molecular weight parameters that enable dual bonding mechanisms. By adjusting the concentration of polar groups versus reactive groups, the adhesive achieves optimal balance between immediate tack and final bond strength, allowing it to function as both a PSA and a chemical bonding adhesive.
3Strength
If dual-curable PSAs combine UV irradiation and thermal curing processes, then adhesion strength is improved, but extra energy or temperature is required before curing is completed, decreasing user-friendliness and application potential
Solution Approach 1:
The patent extracts the thermal curing step from the dual-curing process, retaining only the UV irradiation component. The adhesive is formulated with photoinitiators and reactive groups that enable complete curing through UV light alone, eliminating the need for additional heat or temperature input while maintaining strong adhesion bonds.
Solution Approach 2:
The patent replaces the thermal curing mechanism (heat-based) with a photochemical curing mechanism (UV light-based). This substitution eliminates the need for external heat sources or temperature control, making the curing process simpler, faster, and more suitable for a wider range of applications including sensitive substrates.
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 achieves both strong initial tack and long-term adhesion by sequential UV and moisture curing, ensuring durability and stability in various environmental conditions without requiring extra energy, enhancing the usability and application potential of adhesive tapes.
Implementation Method 1
an adhesive composition cured by exposure to UV... comprising... d. 0.1 - 5 wt% of a photoinitiator
Implementation Method 2
still moisture-curable... a. 5 - 30 wt% silyl terminated prepolymer
Implementation Method 3
formation of a physical connection (i.e. physisorption) caused by electrostatic forces such as hydrogen bonds or electromagnetic forces such as van der Waals forces
Data Source
AI summary
A pressure sensitive adhesive tape obtainable by UV-curing of a dual-curable adhesive composition comprising, based on total weight of the adhesive composition, a. 5 - 30 wt% silyl terminated prepolymer; b. 5 - 90 wt% of one or more (meth)acrylate monomers selected from monofunctional (meth)acrylate monomers and/or multifunctional (meth)acrylate monomers; c. 0-60 wt% of more or more (meth)acrylate oligomers; d. 0.1 - 5 wt% of a photoinitiator; e. 5 - 50 wt% tackifier; f. Optionally: one or more additives selected from the group consisting of: a filler, a moisture scavenger, an adhesion promotor and an organometallic compound catalyst.