Block Copolymer Hot-Melt Adhesive for Creep-Resistant Elastic Bonding
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Solution Overview
Problem
Existing hot-melt adhesives used in manufacturing hygiene products like paper diapers and sanitary products require improved elasticity and creep resistance beyond conventional standards.
Innovation Solution
A hot-melt adhesive comprising a block copolymer composition with specific melt flow rates, Shore A hardness, and monomer unit content, incorporating block copolymers A, B, and optionally C, with controlled molecular weights and monomer compositions to enhance creep resistance and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hot-melt adhesives are used for bonding hygiene products, then basic adhesion is achieved, but creep resistance and elasticity are insufficient
Solution Approach 1:
The patent uses a composite block copolymer system consisting of at least two different block copolymers (e.g., styrene-isoprene-styrene and styrene-butadiene-styrene) with different molecular weights and compositions. This composite approach combines the advantages of each copolymer to achieve both excellent adhesion and creep resistance, resolving the contradiction between reliability and strength.
Solution Approach 2:
The patent optimizes specific parameters including melt flow rate (40-200 g/10 min), Shore A hardness (40-70), and aromatic vinyl monomer unit content (10-80% by weight). By carefully controlling these parameters within specific ranges, the adhesive achieves balanced performance in both adhesion and creep resistance.
2Stability of the object's composition
If block copolymer composition is optimized for creep resistance, then elasticity improves, but adhesion may be compromised
Solution Approach 1:
The patent creates different functional zones within the adhesive system by using block copolymers with different properties. One copolymer provides elastic recovery and creep resistance, while another provides adhesion. This local differentiation of functions within the composite material resolves the contradiction between elasticity and adhesion.
Solution Approach 2:
The patent specifies that the block copolymer composition should have a melt flow rate of 40-200 g/10 min and Shore A hardness of 40-70, with aromatic vinyl monomer content of 10-80% by weight. These parameter optimizations ensure that the adhesive maintains both elastic properties and bonding strength.
Data Source
AI summary
A hot-melt adhesive comprising a block copolymer, wherein the block copolymer has a melt flow rate of 40 to 200 g/10 min, the block copolymer contains an aromatic vinyl polymer block and a conjugated diene polymer block, a content of an aromatic vinyl monomer unit in the block copolymer is 30 to 80% by weight with respect to the total monomer unit constituting the block copolymer, and the block copolymer has a Shore A hardness of 65 or less is provided.