Hydrogenated Block Copolymer Adhesive Composition
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Solution Overview
Problem
Existing adhesive compositions using vinyl aromatic hydrocarbon-conjugated diene based block copolymers face challenges in achieving a balance between retentivity, tackiness, and low melt viscosity, with poor thermal stability and high melt viscosity at high temperatures.
Innovation Solution
A hydrogenated block copolymer composition with specific structural requirements, including 30-90% of one polymer block and 10-70% of another, combined with a tackifier in predetermined proportions, to achieve balanced adhesion properties and reduced melt viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If vinyl aromatic hydrocarbon-conjugated diene based block copolymer (SBS) is used as base polymer, then high versatility is achieved, but thermal stability is poor and melt viscosity is high
Solution Approach 1:
The patent applies parameter changes by controlling the degree of hydrogenation of the conjugated diene units (5-85%) and adjusting the composition ratio between vinyl aromatic hydrocarbon and conjugated diene blocks. This partial hydrogenation approach modifies the polymer's thermal stability and melt viscosity while preserving its versatility as a hot-melt adhesive base polymer.
Solution Approach 2:
The patent creates a composite adhesive system by combining the hydrogenated block copolymer with specific tackifiers (rosin-based resins, terpene-based resins, or petroleum resins) in controlled ratios. This composite approach enhances thermal stability and adjusts melt viscosity while maintaining the core properties of the SBS polymer.
2Adaptability or versatility
If SBS block copolymer is used, then high versatility is achieved, but retentivity and tackiness balance is poor
Solution Approach 1:
The patent optimizes the balance between retentivity and tackiness by precisely controlling the hydrogenation degree (5-85%) of the conjugated diene blocks and the compositional ratio of vinyl aromatic hydrocarbon to conjugated diene units. These parameter adjustments allow tuning of the adhesive's mechanical properties to achieve balanced performance.
Solution Approach 2:
The patent employs composite materials by formulating the hydrogenated block copolymer with specific types and amounts of tackifiers (rosin-based, terpene-based, or petroleum resins). This composite structure enables independent optimization of tackiness (through tackifier content) and retentivity (through polymer backbone properties).
3Strength
If block copolymer with high vinyl content is used, then retentivity improves, but melt viscosity increases and processability decreases
Solution Approach 1:
The patent resolves this contradiction by controlling the hydrogenation degree of the conjugated diene units (5-85%). Partial hydrogenation reduces melt viscosity and improves processability while the remaining unsaturated bonds and optimized vinyl aromatic hydrocarbon content (40-70%) maintain sufficient retentivity. This parameter control allows decoupling of viscosity and retentivity properties.
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 composition exhibits low melt viscosity, good tack strength, retentivity, and high thermal stability, with well-balanced adhesion performance.
Implementation Method 1
a hydrogenated block copolymer having 30 to 90% by mass of (1-A) below and 70 to 10% by mass of (1-B) below: (1-A) a hydrogenated block copolymer that comprises a polymer block mainly composed of a vinyl aromatic hydrocarbon and a polymer block mainly composed of a conjugated diene compound, and satisfies requirements (a) to (c) below: (a) a total degree of hydrogenation H (%) of unsaturated double bonds based on the conjugated diene compound is 10 to 80%
Data Source
AI summary
An adhesive composition having good balance in tackiness properties such as tack strength and retentivity, low melt viscosity, high processability, and high stability in melt viscosity under high temperature heating is provided. An adhesive composition containing two hydrogenated block copolymers and a predetermined tackifier is provided, the two hydrogenated block copolymers each having a different structure obtained by controlling the degree of hydrogenation of a block copolymer of a conjugated diene compound and a vinyl aromatic hydrocarbon in a particular range.