PVC Adhesive Sheet Preventing Plasticizer Migration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional adhesive sheets using polyvinyl chloride suffer from migration of plasticizer, leading to decreased chip-holding ability in dicing and poor chip-exfoliating ability in picking-up processes.
Innovation Solution
An adhesive sheet with a polyvinyl chloride substrate and a specific adhesive composition containing (meth)acrylate copolymers and a polyester-based plasticizer, where the copolymers have distinct weight-average molecular weights and functional group-containing monomer units, along with a controlled cross-linking agent content, to prevent plasticizer migration and maintain adhesive performance over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyvinyl chloride is used as the substrate material, then the substrate provides good mechanical properties and processing performance, but plasticizer migration occurs over time causing deterioration of chip-holding ability and chip-exfoliating ability
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between the polyvinyl chloride substrate and the adhesive layer. The silane coupling agent contains both inorganic characteristics (for bonding to substrate) and organic characteristics (for compatibility with adhesive), thereby preventing plasticizer migration from the substrate to the adhesive layer while maintaining both chip-holding and chip-exfoliating abilities
Solution Approach 2:
The substrate is formulated as a composite material combining polyvinyl chloride with silane coupling agent. This composite structure provides both the mechanical properties of PVC and the migration-preventing properties of silane, resolving the contradiction between mechanical performance and compositional stability
2Strength
If adhesive force increases with time, then bonding strength is improved, but chip-exfoliating ability deteriorates
Solution Approach 1:
The glass transition temperature of the adhesive is precisely controlled within -50°C to 0°C through selection of specific polymer components and ratios. This parameter control allows the adhesive to maintain optimal bonding strength while preventing excessive strength increase over time, thereby preserving chip-exfoliating ability
Solution Approach 2:
Different regions of the adhesive layer exhibit different properties: near the substrate, the adhesive provides strong bonding through controlled Tg, while the overall composition maintains lower cross-linking density to allow for future exfoliation. This spatial differentiation of adhesive properties resolves the contradiction between bonding strength and exfoliating ability
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 adhesive sheet maintains chip-holding and chip-exfoliating abilities without deterioration, ensuring reliable performance in dicing and picking-up processes.
Implementation Method 1
a silane coupling agent which has both inorganic and organic characteristics and forms a cross-linked structure
Data Source
AI summary
An adhesive sheet of the invention includes a substrate and an adhesive composition laminated thereon, the substrate including polyvinyl chloride and a polyester-based plasticizer, wherein the adhesive composition includes two different (meth)acrylate copolymer components (A) and (B) in a mass ratio ranging from 10:90 to 90:10, wherein a content of a cross-linking agent which reacts with functional groups of the component (A) and the component (B) is in a range of 0.5 to 20 mass parts with respect to 100 mass parts of a sum of the component (A) and the component (B), and wherein 10 to 95 mass % of the monomer unit composing the component (A) is 2-ethylhexyl acrylate, and 10 to 95 mass % of the monomer unit composing the component (B) is butyl acrylate.