Block Copolymer Adhesive Composition Heat Stability
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Solution Overview
Problem
Existing adhesive compositions based on styrenic block copolymers, such as S-I-S and S-B-S, face issues with heat stability and cohesive strength, leading to degradation and increased elastic modulus, making them unsuitable for industrial applications, and the use of multiple block copolymers and hydrocarbon resins is costly and complex.
Innovation Solution
Combining S-I-S or S-B diblock copolymers with S-(I/B) diblock copolymers and a single C5 hydrocarbon resin tackifier, resulting in adhesive compositions with improved heat stability and cost-effectiveness by optimizing the weight ratio of butadiene content and using a single, inexpensive tackifying resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If S-I-S block copolymer is used in adhesive compositions, then pressure sensitive adhesive properties are improved, but heat stability deteriorates due to chain scission mechanism
Solution Approach 1:
The patent combines S-I-S block copolymer with S-B-S block copolymer in a specific weight ratio (40:60 to 60:40) to create a synergistic adhesive composition that maintains the pressure sensitive properties of S-I-S while benefiting from the heat stability of S-B-S, resolving the contradiction between adhesive performance and heat resistance
Solution Approach 2:
The invention creates a composite adhesive system using two different block copolymers with complementary properties, where S-I-S provides tack and adhesion while S-B-S provides thermal stability and cohesion, forming a composite material that overcomes the limitations of individual polymers
2Strength
If S-B-S block copolymer is used in adhesive compositions, then cohesive strength and heat stability are improved, but elastic modulus increases making the adhesive too hard and non-tacky
Solution Approach 1:
The patent merges S-B-S block copolymer (providing cohesive strength) with S-I-S block copolymer (providing tackiness) in optimized ratios to balance the adhesive properties, ensuring the composition has both sufficient strength and adequate tack for pressure sensitive applications
Solution Approach 2:
The invention optimizes the weight ratio parameters of the two block copolymers (40:60 to 60:40 range) to achieve the desired balance between cohesion and tackiness, adjusting the composition parameters to resolve the contradiction between strength and ease of application
3Reliability
If multiple block copolymers and hydrocarbon resins are used to achieve desired adhesive properties, then adhesive performance is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent combines two block copolymers in a specific ratio to achieve the desired adhesive performance, eliminating the need for multiple hydrocarbon resins and simplifying the formulation process while maintaining or improving adhesive reliability
Solution Approach 2:
The S-B-S block copolymer serves multiple functions in the composition: it provides heat stability, enhances cohesive strength, and acts as a processing aid, reducing the need for additional specialized additives and simplifying the overall formulation
Data Source
AI summary
Less expensive adhesive compositions having good adhesive properties can be achieved by combining an S-I-S or (SI)nX block copolymers with an S-(I/B) diblock copolymer and a single tackifying resin. Furthermore, less expensive adhesive compositions can be achieved by combining S-I diblock copolymers with S-(I/B)-S or [S(I/B)]nX block copolymers and a single tackifying resin. These combinations result in lower costs of starting materials and manufacturing due to simpler processing.