Two-Part Structural Adhesive with Epoxidized Silane
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Solution Overview
Problem
Acrylic-based structural adhesives often exhibit lower bonding performance on composite materials, particularly those manufactured in closed molds, due to issues like plasticizer migration and adhesion defects, leading to reduced tensile shear strength and potential detachment under mechanical stress.
Innovation Solution
A formulation combining a free radical polymerization initiating agent with epoxidized silane, which reduces the presence of plasticizing agents and enhances adhesion, specifically using epoxidized silanes like β-(3,4-epoxycyclohexyl)ethyl-triethoxysilane and functional epoxy silane oligomers, along with a peroxide-based polymerization initiator, to improve the mechanical performance of (meth)acrylate adhesives on composite substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If acrylic-based structural adhesives are used for bonding composite materials, then the polymerization profile and ease of use on unprepared surfaces are improved, but the bonding performance and tensile shear strength are reduced compared to epoxy adhesives
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive system by incorporating specific silane coupling agents and optimizing the resin formulation to enhance bonding performance while maintaining the ease of use characteristics of acrylic adhesives
Solution Approach 2:
The invention creates a composite adhesive system combining acrylic resin with silane coupling agents and other functional additives to achieve both high bonding performance on composite materials and ease of application on unprepared surfaces
2Strength
If plasticizing agents are added to the catalytic composition to improve flexibility, then the adhesion is enhanced, but the plasticizers migrate into the composite material causing adhesion defects and reducing bonding strength
Solution Approach 1:
The patent extracts or removes the harmful plasticizing agents from the adhesive formulation while maintaining adhesion through alternative mechanisms provided by silane coupling agents and optimized resin composition
Solution Approach 2:
The invention introduces silane coupling agents as intermediary substances that provide adhesion enhancement without the migration problems associated with plasticizers, acting as a bridge between the adhesive and composite substrate
3Strength
If surface preparation steps like abrasion and degreasing are performed to eliminate adhesion defects, then the bonding performance is improved, but the manufacturing time and process complexity increase
Solution Approach 1:
The adhesive formulation is designed to self-prepare the surface through chemical interaction, with the silane coupling agents and optimized resin composition enabling direct bonding to composite surfaces without requiring mechanical abrasion or chemical degreasing steps
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 significantly enhances the tensile shear strength of the adhesive, achieving values greater than 2 MPa, thereby improving the structural integrity and resistance to mechanical stress, water infiltration, and thermal shocks in bonded composite materials.
Implementation Method 1
This catalyst agent contains free radical polymerization initiators, and is added to the resin containing the monomer agents, to initiate polymerization, thus ensuring the cohesive junction of two materials.
Implementation Method 2
The invention thus relates to a composition usable in a structural adhesive, comprising a free radical polymerization initiating agent as well as an epoxidized silane.
Data Source
AI summary
The invention relates to a two-component structural adhesive comprising a (meth)acrylic resin containing acrylate or methacrylate monomers, and a polymerization catalyst agent, intended to be added to said resin, comprising a free-radical polymerization initiator and an epoxy silane, said epoxy silane being between 1 and 30% by weight.