Block Copolymer Adhesive Composition for Die-Cutting and Anti-Migration
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Solution Overview
Problem
Existing adhesive compositions face challenges in achieving excellent die-cutting properties, softening agent anti-migration performance, mandrel properties, and transparency simultaneously, as previous solutions either fall short in die-cutting or struggle to combine all required properties effectively.
Innovation Solution
A block copolymer composition comprising specific triblock and diblock copolymers with controlled molecular weights and monomer unit ratios, along with a softening agent and optional tackifying resin, elastomer, and antioxidant, to enhance compatibility and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a styrene-isoprene diblock copolymer and tackifier are blended to improve adhesion, then adhesive ability is enhanced, but die-cutting properties deteriorate due to thread formation and sticking to the die
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a specific aromatic vinyl-isoprene diblock copolymer with controlled aromatic vinyl monomer content (10-40 wt%) and combining it with a polyolefin elastomer and specific tackifier ratios. This parameter optimization resolves the contradiction by adjusting the balance between adhesion and die-cutting properties through precise compositional control
Solution Approach 2:
The patent creates a composite adhesive material system comprising multiple components: aromatic vinyl-isoprene diblock copolymer, polyolefin elastomer, and tackifier in specific proportions. This composite approach allows the material to simultaneously achieve good adhesion from the elastomer and die-cutting performance from the optimized copolymer-tackifier combination, preventing thread formation
2Ease of manufacture
If softening agent is added to lower processable temperature and improve tackiness, then processability is enhanced, but softening agent migration and contamination occur
Solution Approach 1:
The patent uses the aromatic vinyl-isoprene diblock copolymer as an intermediary substance that facilitates softening agent incorporation while preventing its migration. The copolymer acts as a matrix that holds the softening agent through specific intermolecular interactions, allowing low processing temperature without contamination of the adherend surface
3Manufacturing precision
If adhesive composition is formulated to achieve excellent die-cutting properties, then manufacturing precision is improved, but softening agent anti-migration performance and transparency may be compromised
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: aromatic vinyl monomer content (10-40 wt%), polyolefin elastomer content (30-80 wt%), and tackifier content (5-50 wt%). This multi-parameter optimization creates a balanced formulation that achieves die-cutting performance while maintaining softening agent retention and transparency through controlled molecular interactions
Data Source
AI summary
A main object of the present disclosure is to provide a block copolymer composition that allows an adhesive composition having excellent die-cutting properties, softening agent anti-migration performance, mandrel properties and transparency to be obtained. The object is achieved by providing a block copolymer composition comprising: a block copolymer A represented by the following formula (I); and a block copolymer B represented by the following formula (II); characterized in that: a content of an aromatic vinyl monomer unit of the block copolymer A is more than a content of an aromatic vinyl monomer unit of the block copolymer B; a weight average molecular weight of aromatic vinyl polymer block Ar3 (Mw(Ar3)) of the block copolymer B is substantially the same as a weight average molecular weight of aromatic vinyl polymer block Ar1 (Mw(Ar1)) of the block copolymer A; and breaking strength of the block copolymer composition is 8 MPa or less and breaking elongation of the block copolymer composition is 2000% or less.