Dual Curable Polymers for Adhesives
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Solution Overview
Problem
Current radiation curable adhesives and sealants lack elastomeric properties and high temperature resistance, while moisture-curing adhesives require surface pretreatment and have limited flexibility under elevated temperatures.
Innovation Solution
Development of radiation/moisture dual curable polymers with specific terminal groups that allow for crosslinking under both radiation and moisture exposure, providing a combination of fast curing and slow curing mechanisms, and incorporating polyoxyethylene or polyoxyethylene-polyoxypropylene backbones for enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If radiation curable adhesives are used, then fast curing is achieved, but elastomeric properties and high temperature resistance are lacking
Solution Approach 1:
The patent combines radiation curable groups (acrylate, vinyl, or nitrile) with moisture curable silane terminal groups in the same polymer chain. This merging allows the adhesive to undergo both radiation-induced crosslinking for fast curing and moisture-induced crosslinking for enhanced elastomeric properties and heat resistance, resolving the contradiction between curing speed and material performance
Solution Approach 2:
The invention creates a composite polymer structure containing both radiation-responsive functional groups and moisture-responsive silane groups. This composite approach enables dual curing mechanisms to operate simultaneously or sequentially, achieving both rapid initial set (radiation) and final cured properties (moisture curing) that provide elastomeric behavior and thermal stability
2Reliability
If moisture-curing adhesives are used, then elastomeric properties and adhesion are improved, but surface pretreatment is required and flexibility under elevated temperatures is limited
Solution Approach 1:
The polymer is designed with multi-functional terminal groups that provide both radiation curability and moisture curability. The silane terminal groups enable moisture curing for broad substrate adhesion without pretreatment, while the incorporated radiation-responsive groups allow alternative fast curing pathways, making the adhesive universally applicable to various substrates and curing conditions
3Adaptability or versatility
If silane-modified polymers are used, then broad adhesion and chemical curability are achieved, but deformability under elevated temperatures occurs
Solution Approach 1:
The patent modifies the silane terminal group structure by incorporating specific radiation-responsive functional groups (acrylate, vinyl, or nitrile) that change the crosslinking parameters. The dual curing system creates a more densely crosslinked network with higher crosslink density, which increases the glass transition temperature and reduces thermal deformation, thereby improving dimensional stability while maintaining broad adhesion properties
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 dual curable polymers exhibit improved elastomeric properties and high temperature resistance without the need for surface pretreatment, offering a flexible and durable adhesive solution.
Implementation Method 1
Radiation curable adhesives are widely used and can form crosslinks (cure) upon sufficient exposure to radiation such as electron beam radiation or actinic radiation such as ultraviolet (UV) radiation or visible light
Implementation Method 2
Moisture-curable, as used herein, thus relates to curing under the influence of moisture, typically humidity from the surrounding air
Data Source
AI summary
The present invention relates to radiation or radiation/moisture dual curable polymers and methods for their manufacture. These polymers are useful for various applications in the fields of adhesives, coatings, and sealants. The radiation curable polymers comprise at least one terminal group of the general formula (I) -A1-C(=O)-CR1=CH2 (I), wherein A1 is a divalent bonding group containing at least one heteroatom; and R1 is selected from H and C1-C4 alkyl, preferably H and methyl; wherein the polymer backbone is selected from the group consisting of polyoxyalkylenes, poly(meth)acrylates, polyesters, and combinations thereof. and optionally further comprise at least one terminal group of the general formula (II) -A2-SiXYZ (II), wherein X, Y, Z are, independently of one another, selected from the group consisting of a hydroxyl group and C1 to C8 alkyl, C1 to C8 alkoxy, and C1 to C8 acyloxy groups, wherein X, Y, Z are substituents directly bound with the Si atom or the two of the substituents X, Y, Z form a ring together with the Si atom to which they are bound, and at least one of the substituents X, Y, Z is selected from the group consisting of a hydroxyl group, C1 to C8 alkoxy and C1 to C8 acyloxy groups; and A2 is a divalent bonding group containing at least one heteroatom.