Modified Acrylic Block Copolymer Heat Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional acrylic block copolymers exhibit poor heat resistance and limited miscibility with other resins, leading to inadequate cohesion force at high temperatures, which results in cohesive failure and residual adhesive issues.
Innovation Solution
A modified acrylic block copolymer comprising a polymer block with a (meth)acrylic acid ester unit and an N-substituted (meth)acrylamide unit, where the weight average to number average molecular weight ratio is 1.0 to 1.5, and the polymer block further includes a (meth)acrylic acid unit, with specific molar relationships and structural units, is produced by reacting a block copolymer with an amine compound to enhance heat resistance and tackiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional acrylic block copolymer is used, then the adhesive provides initial tackiness, but the cohesion force decreases at high temperatures leading to adhesive failure
Solution Approach 1:
The invention uses a block copolymer composite structure consisting of a hard segment (polymer block A with Tg ≥ +110°C) and a soft segment (polymer block B with Tg ≤ +30°C). This composite structure allows the hard segment to maintain cohesion force at high temperatures while the soft segment provides tackiness, resolving the contradiction between initial adhesion and heat resistance.
Solution Approach 2:
The invention applies local quality by creating distinct functional regions within the adhesive: the hard segment (polymer block A) localized to provide thermal stability and cohesion force, and the soft segment (polymer block B) localized to provide tackiness and adhesion. This spatial differentiation of properties allows simultaneous achievement of both adhesion and heat resistance.
2Temperature
If the glass transition temperature of the polymer block is increased to improve heat resistance, then the adhesive loses tackiness and forming processability
Solution Approach 1:
The invention segments the polymer into two distinct blocks with different glass transition temperatures: polymer block A (Tg ≥ +110°C) for heat resistance and polymer block B (Tg ≤ +30°C) for tackiness. This segmentation allows each block to independently fulfill its functional requirement without compromising the other, resolving the contradiction between heat resistance and ease of operation.
Solution Approach 2:
The invention changes the parameter of glass transition temperature distribution by creating a bimodal Tg structure through block copolymerization. The presence of low-Tg polymer block B ensures adequate tackiness and forming processability, while the high-Tg polymer block A ensures heat resistance, thus resolving the contradiction through parameter optimization.
3Temperature
If a methacrylic resin is modified to improve heat resistance, then the plasticity and miscibility with other resins deteriorate
Solution Approach 1:
The invention optimizes the parameter of molecular weight distribution by controlling Mw/Mn to be 1.05 to 1.30, and adjusts the compositional parameters (polymer block A content: 10-40 mass%, polymer block B content: 60-90 mass%) to achieve a balance between heat resistance and miscibility with other resins, resolving the contradiction through precise parameter control.
Solution Approach 2:
The invention introduces functional units locally within the polymer structure: polymer block A contains units that provide heat resistance, while polymer block B contains units that enhance plasticity and miscibility. This localized functional distribution allows the adhesive to simultaneously achieve heat resistance and adaptability with other resins.
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 modified acrylic block copolymer demonstrates improved heat resistance, tackiness, and forming processability, maintaining excellent adhesion even under ultraviolet exposure and high temperature and humidity conditions.
Implementation Method 1
the polymer block having a high glass transition temperature serves as a physical crosslinking site and gives cohesion force
Data Source
AI summary
A modified acrylic block copolymer is obtained by a method comprising subjecting a block copolymer (C) to a reaction with an amine compound, wherein the block copolymer comprises a polymer block (A) comprising a (meth)acrylic acid ester unit (a) and a polymer block (B') comprising a (meth)acrylic acid ester unit (b'), the (meth)acrylic acid ester unit (a) is structurally different from the (meth)acrylic acid ester unit (b'), thereby partly or entirely converting the (meth)acrylic acid ester unit (b') into at least one selected from the group consisting of an N-substituted (meth)acrylamide unit (d), a (meth)acrylic acid unit (c), and an N-substituted bis((meth)acryl)amide unit (e).