Moisture-Curable Polyurethane Hot Melt Adhesive for Multilayer Sheets
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Solution Overview
Problem
Conventional moisture-curable polyurethane hot melt adhesives used in multilayer sheets experience a reduction in adhesion strength when subjected to repeated water washing, dry cleaning, or industrial washing, leading to separation between substrates, while also compromising the soft texture of the materials.
Innovation Solution
A moisture-curable polyurethane hot melt adhesive is developed, comprising a urethane prepolymer formed by reacting a polyol mixture of 40-80% polycarbonate polyol, 5-40% polytetramethylene glycol, and 5-40% polyester polyol, which enhances adhesion strength and maintains soft texture even under stringent washing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional moisture-curable polyurethane hot melt adhesive is used, then adhesion strength is initially good, but adhesion strength reduces after repeated water washing, dry cleaning, or industrial washing causing separation between substrates
Solution Approach 1:
The patent changes the chemical composition parameters of the polyol component by incorporating specific ratios of polycarbonate polyol (40-80 mass%), polyester polyol (5-40 mass%), and polyether polyol (5-40 mass%). This parameter change in composition resolves the contradiction by providing both initial adhesion strength and long-term durability after repeated washing, as the specific polyol blend maintains adhesive properties under various washing conditions
Solution Approach 2:
The patent uses a composite polyol system combining multiple types of polyols (polycarbonate, polyester, and polyether polyols) in specific proportions. This composite material approach resolves the technical contradiction by leveraging the complementary properties of each polyol type to achieve both strong initial adhesion and sustained durability after repeated water washing, dry cleaning, and industrial washing
2Reliability
If reactive hot melt adhesive with multiple polyol components is used, then separation between substrates is prevented during water washing, but adhesion strength significantly reduces during industrial washing
Solution Approach 1:
The patent optimizes the mass percentage parameters of each polyol component: polycarbonate polyol (40-80%), polyester polyol (5-40%), and polyether polyol (5-40%). This precise parameter control resolves the contradiction by balancing the adhesive's resistance to substrate separation during water washing with maintained adhesion strength under more stringent industrial washing conditions
3Strength
If adhesive is applied to multilayer sheet, then substrates are bonded together, but soft texture of the multilayer sheet is impaired
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by using a specific blend of polyols with controlled molecular weights and ratios. This parameter change enables the adhesive to provide strong bonding between substrates while maintaining the soft texture of the multilayer sheet, as the polyol composition allows for flexible yet strong adhesion
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 maintains excellent adhesion strength and soft texture of multilayer sheets during repeated water washing, dry cleaning, and industrial washing, preventing substrate separation and ensuring durability and flexibility.
Implementation Method 1
a urethane prepolymer obtained by reacting a polyol (A) with a polyisocyanate (B)
Implementation Method 2
moisture-curable polyurethane hot melt adhesive
Data Source
Figure 1~2
AI summary
There are provided a moisture-curable polyurethane hot melt adhesive containing a urethane prepolymer obtained by reacting a polyol (A) with a polyisocyanate (B), wherein the polyol (A) contains 40 to 80 mass% of a polycarbonate polyol (a1), 5 to 40 mass% of polytetramethylene glycol (a2), and 5 to 40 mass% of a polyester polyol (a3) obtained by reacting a polycarboxylic acid containing an aliphatic polycarboxylic acid and an aromatic polycarboxylic acid with a polyether polyol obtained by adding an alkylene oxide to bisphenol A, based on the total amount of the polyol (A), and a multilayer sheet using this adhesive. This adhesive can maintain excellent adhesion strength even after washing is repeatedly performed under stringent washing conditions without impairing soft texture of a multilayer sheet.