Core-Shell Impact Modifier for Methacrylate Adhesives
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Solution Overview
Problem
Current (meth)acrylic adhesive compositions face challenges with toughener additives like Kraton D 1155 and Hypro RLP 200X 168 VTM, which are not easily dispersible or miscible in (meth)acrylates, leading to processability and cost issues, and resulting in inconsistent performance due to improper dispersion.
Innovation Solution
Incorporating a core-shell impact modifier with a polymeric core and gradient polymer layers, along with polybutadiene rubber particles or liquid methacrylate-terminated polybutadiene polymer, to create a two-part adhesive composition that is readily miscible and enhances impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional tougheners (Kraton D 1155, Hypro RLP 200X 168 VTM) are used to improve impact resistance, then impact resistance performance increases, but dispersibility and miscibility in (meth)acrylates deteriorate
Solution Approach 1:
The patent uses a core-shell impact modifier where the core is made of polybutadiene rubber particles and the shell is made of (meth)acrylate polymer. This composite structure allows the rubber core to provide impact resistance while the (meth)acrylate shell ensures compatibility and easy dispersion in the adhesive matrix, resolving the contradiction between strength improvement and ease of manufacture
Solution Approach 2:
The patent modifies the physical and chemical parameters of the toughener by creating a core-shell structure with specific glass transition temperatures and compositional gradients. The shell layer parameters are adjusted to match the adhesive matrix, improving miscibility and dispersibility while maintaining the impact-resistant properties of the rubber core
2Strength
If conventional tougheners are used to enhance impact resistance, then performance characteristics improve, but processing time and cost increase
Solution Approach 1:
The core-shell structure with a (meth)acrylate shell layer changes the solubility and reactivity parameters of the toughener, allowing it to mix readily with the adhesive matrix without requiring extensive processing time for dispersion or special incorporation procedures
3Strength
If conventional tougheners are used to improve impact resistance, then toughness increases, but miscibility in (meth)acrylates deteriorates
Solution Approach 1:
The core-shell impact modifier creates a composite material where the inner core provides toughness and the outer shell provides miscibility. The shell is composed of (meth)acrylate polymer that is chemically compatible with the adhesive matrix, ensuring stable mixing and homogeneous distribution while the rubber core maintains the toughness enhancement
Data Source
AI summary
Structural adhesives containing a core-shell toughening component miscible in methylacrylic-based adhesives in addition to at least one toughening agent which is not miscible in methacrylic adhesives, produced surprisingly improved impact resistance, particularly side impact testing.