Block Copolymer Adhesive Composition for Tack and Workability Balance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Viscous adhesive compositions based on block copolymers, such as SBS and SIS, face challenges in achieving a balance between tack strength, solubility, coating properties, ejection stability, and surface skin quality, with existing solutions offering insufficient improvements.

Innovation Solution

A block copolymer composition comprising two specific non-hydrogenated block copolymers with defined molecular weights and structures, a tackifier, and a softener, optimized to achieve a balance between tack strength and tackiness, with a low melt viscosity and improved solubility, coating properties, and surface skin quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a block copolymer with high melt viscosity is used to improve adhesion properties, then tack strength is improved, but workability and coating properties deteriorate

Engineering Contradiction:

Improvetack strengthVSAvoidworkability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent segments the block copolymer into two distinct components with different molecular weights: a low molecular weight component (10,000-60,000) for workability and a high molecular weight component (120,000-200,000) for adhesion. This segmentation allows each component to fulfill its specific function without compromising the other, resolving the contradiction between tack strength and workability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the molecular weight parameter by using a bimodal distribution rather than a single molecular weight. The specific ranges (10,000-60,000 and 120,000-200,000) are carefully selected to optimize both adhesion and workability, demonstrating parameter changes as a key inventive principle.

Inventive Principle:

Principle #35Parameter changes

2Strength

If a block copolymer with high molecular weight is used to improve adhesion, then tack strength is improved, but solubility and coating properties deteriorate

Engineering Contradiction:

Improvetack strengthVSAvoidsolubility

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent segments the polymer composition into low and high molecular weight components, where the low molecular weight component (10,000-60,000) provides excellent solubility and coating properties, while the high molecular weight component (120,000-200,000) provides tack strength. This segmentation resolves the contradiction between adhesion and solubility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a composite polymer system combining two block copolymers with different molecular weights. This composite approach allows the system to exhibit properties of both components: good solubility from the low molecular weight component and high adhesion from the high molecular weight component.

Inventive Principle:

Principle #40Composite materials

3Strength

If a block copolymer composition is optimized for tack strength, then adhesion properties are improved, but surface skin quality deteriorates

Engineering Contradiction:

Improvetack strengthVSAvoidsurface skin quality

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent segments the composition into two molecular weight components where the low molecular weight component (10,000-60,000) contributes to surface skin quality by providing better flow and leveling, while the high molecular weight component (120,000-200,000) provides tack strength. This segmentation resolves the contradiction between adhesion and surface quality.

Inventive Principle:

Principle #1Segmentation

4Strength

If a block copolymer with high melt viscosity is used to improve adhesion, then tack strength is improved, but ejection stability deteriorates

Engineering Contradiction:

Improvetack strengthVSAvoidejection stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent segments the polymer into low and high molecular weight components, where the low molecular weight component (10,000-60,000) provides better ejection stability due to lower viscosity, while the high molecular weight component (120,000-200,000) provides tack strength. This segmentation resolves the contradiction between adhesion and ejection stability.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP2878644B1Block copolymer composition for adhesives, and adhesive composition

Publication Date: 2019.05.01 JAPAN ELASTOMER CO LTD

AI summary

It is an object to provide a block copolymer composition for a viscous adhesive, which will be a viscous adhesive composition excellent in balance of the adhesive properties such as tack strength and tackiness, having a low melt viscosity, and excellent solubility, coating properties, ejection stability, and surface skin quality. The block copolymer composition for a viscous adhesive having: a component (a) in an amount of 50 mass% or more and 90 mass% or less; and a component (b) in an amount of 10 mass% or more and 50 mass% or less; a content of the vinyl aromatic monomer unit being 25 to 50 mass%; a viscosity of the 15 mass% toluene solution being 10 to 40 mPa·s; and a number average molecular weight ratio of the component (b) to the component (a) being 2.0 to 4.0.