Two-Part Cyanoacrylate Adhesive for Cure-Through-Volume Bonding
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Solution Overview
Problem
Conventional cyanoacrylate adhesives face limitations in 'cure through volume' (CTV) and durability, particularly when bonding low surface energy substrates and in thicker bondlines, while maintaining rapid bonding speed and multi-substrate compatibility.
Innovation Solution
A two-part curable composition comprising a first part with cyanoacrylate and (meth)acrylic monomers, and a second part with a non-reactive diluent and transition metal catalyst, allowing for simultaneous initiation throughout the adhesive bulk and enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-component cyanoacrylate adhesives are used, then rapid bonding speed and multi-substrate compatibility are achieved, but cure through volume and durability are limited
Solution Approach 1:
The adhesive system is divided into two separate components: Part A containing cyanoacrylate monomer and peroxide initiator, and Part B containing activator and carrier. This segmentation allows each component to be optimized independently - the cyanoacrylate provides rapid bonding and multi-substrate compatibility, while the added peroxide and activator systems enable bulk cure through volume and enhanced durability without compromising the other properties.
Solution Approach 2:
The invention creates a composite adhesive system by combining cyanoacrylate monomer with peroxide initiator and activator components. This composite formulation enables simultaneous achievement of rapid bonding (from cyanoacrylate), bulk cure (from peroxide activation), and enhanced durability (from crosslinked network formation), resolving the contradiction between reliability and complexity.
2Reliability
If activators are applied to substrate surfaces, then bonding to low surface energy substrates is improved, but cure through volume in thicker bondlines is limited
Solution Approach 1:
The peroxide initiator acts as an intermediary that mediates between the cyanoacrylate monomer and the activator. The peroxide decomposes to form free radicals that can initiate polymerization throughout the bulk adhesive, enabling cure through volume while the activator continues to enhance bonding to low surface energy substrates. This intermediary mechanism resolves the contradiction by decoupling the two functions.
Solution Approach 2:
The invention changes the chemical parameters of the adhesive system by introducing peroxide initiator and activator components. This parameter change enables the adhesive to achieve bulk cure through volume activation while maintaining the ability to bond to low surface energy substrates, as the chemical mechanism operates independently of substrate surface properties in the bulk material.
3Speed
If monofunctional monomer is used, then rapid bonding speed is maintained, but durability is limited due to linear polymer chain structure
Solution Approach 1:
The invention applies local quality by introducing multifunctional monomers at specific locations within the adhesive formulation. These multifunctional monomers create crosslinked networks in the bulk material to enhance durability, while the primary cyanoacrylate monomer maintains rapid bonding speed. The local introduction of crosslinking capability without compromising the overall rapid bonding mechanism resolves the contradiction between speed and reliability.
Solution Approach 2:
The adhesive system uses a composite monomer formulation combining cyanoacrylate with multifunctional monomers. This composite approach allows the cyanoacrylate to provide rapid bonding speed while the multifunctional components create crosslinked networks for enhanced durability. The synergistic combination resolves the contradiction by achieving both fast bonding and long-term reliability through appropriate material selection.
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 achieves cure through volume and significantly enhanced durability, retaining rapid bonding speed and multi-substrate compatibility, suitable for indoor and outdoor domestic applications.
Implementation Method 1
a second part (Part B) comprising: i. at least 50 wt. % of a non-reactive diluent, and ii. from 0.001 wt. % to 2 wt. %, preferably from 0.01 wt. % to 0.5 wt. %, of a transition metal catalyst, expressed as the content of the transition metal
Implementation Method 2
a) a first part (part A) comprising: i. at least 50 wt. % of one or more cyanoacrylate monomer(s), ii. at least 1 wt. % of one or more (meth)acrylic monomer(s), and iii. at least 1 wt. % of a per-compound
Data Source
AI summary
The present invention refers to a curable two-part adhesive composition comprising a first part comprising one or more cyanoacrylate monomer(s), one or more (metha)acrylate monomer(s), a per-compound and, optionally, additives to control viscosity and rheology; and a second part comprising: a non-reactive diluent and a transition metal catalyst, and optionally an electron rich initiator for cyanoacrylates. It also relates to a syringe or a cartridge comprising said two-part curable composition, to the use of such composition for bonding substrates, to the use of such composition filling depressions, cracks or holes in a substrate or between substrates to a method for bonding substrates using said composition, and to a repair method for filling depressions, cracks or holes in a substrate or between substrates using said composition.