High-Strength Acrylic Adhesives Using Polyvinyl Butyral Resin
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional acrylic adhesives have limited terminal bond strengths, restricting their applications and requiring elevated cure temperatures, whereas there is a need for a high-strength, room temperature curing adhesive to replace epoxies and achieve strong bonding across various substrates.
Innovation Solution
A two-part acrylic adhesive formulation incorporating a polyvinyl acetal resin with greater than 60% polyvinyl butyral (PVB) that includes reactive monomers, impact modifiers, adhesion promoters, and free-radical polymerization initiators, allowing for high-strength bonding at room temperature and rapid handling strength development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional acrylic adhesive formulations are used, then ease of application and quick drying are achieved, but terminal bond strength is limited
Solution Approach 1:
The patent applies composite materials by combining acrylic adhesive polymers with polyvinyl butyral (PVB) in a multi-component formulation. This composite approach integrates the fast-drying properties of acrylics with the high bond strength characteristics of PVB, achieving both quick handling and superior terminal bond strength that neither material could provide alone.
Solution Approach 2:
The patent utilizes parameter changes by controlling the molecular weight, composition ratios, and curing conditions of the adhesive formulation. By optimizing parameters such as the ratio of acrylic to PVB components, initiator concentration, and curing temperature profiles, the formulation achieves high bond strength while maintaining ease of application and quick drying characteristics.
2Strength
If elevated cure temperature adhesives such as epoxies are used, then high bond strength is achieved, but room temperature applicability is lost
Solution Approach 1:
The patent employs an intermediary approach by using a redox curing system that mediates between room temperature conditions and the high bond strength requirement. The redox initiators enable polymerization to proceed at ambient temperatures, eliminating the need for elevated cure temperatures while still achieving epoxy-like bond strengths through the synergistic action of acrylic and PVB components.
3Strength
If conventional fastening techniques such as rivets and bolts are used, then mechanical strength is achieved, but stress concentration and corrosion are increased
Solution Approach 1:
The patent replaces mechanical fastening systems (rivets, bolts, welds) with a chemical bonding system. The adhesive formulation creates a continuous bond that distributes stresses uniformly across the joint, eliminating the stress concentration points inherent in mechanical fasteners. The redox-curing acrylic-PVB system provides corrosion resistance while maintaining mechanical strength through chemical adhesion rather than mechanical interlocking.
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 formulation achieves significantly higher bond strengths and durability, enabling strong adhesion to diverse substrates like metals and plastics, with conductive fillers providing electrical conductivity and thermal management, surpassing conventional acrylic adhesives in lap shear strength and tensile modulus.
Implementation Method 1
free-radical curing acrylic adhesives
Implementation Method 2
The adhesive mixture then cures to create a bond between the substrate and the second substrate
Data Source
AI summary
A two-part formulation of a high strength acrylic adhesive that includes a Part A and Part B. The Part A includes at least one curable monomer of: Part A acrylate monomer, methacrylate monomer, acrylic acid monomer, methacrylic acid monomer, or a combination thereof; a Part A impact modifier; and a Part A adhesion promoter. A Part B includes impact modifier, a Part B adhesion promoter, and an induction agent. A polyvinyl acetal resin is present in at least one of Part A or Part B, and present from 1 to 30 total weight percent. A process of applying the resulting adhesive to bond substrates and a resulting structure are also provided.