Moisture-Curable Polyurethane Hot-Melt Adhesive Composition
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Solution Overview
Problem
Moisture-curable polyurethane hot-melt adhesives lack sufficient water resistance, fast-curing properties, and flexibility, making them impractical for applications requiring these superior properties, especially in the lamination of optical elements and construction materials.
Innovation Solution
A moisture-curable polyurethane hot-melt resin composition is developed, comprising a reaction product of polyols such as polyether, crystalline polyester, amorphous polyester, and acrylic polyols with a polyisocyanate, along with a specific curing catalyst, to create an isocyanate-containing urethane prepolymer that reacts with moisture for fast curing and provides enhanced water resistance and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a moisture- and heat-resistant hot-melt adhesive composition containing polyurethane resin, saturated polyester resin, epoxy resin, and inorganic filler is used, then moisture and heat resistance are improved, but water resistance becomes insufficient and the adhesive has insufficient flexibility
Solution Approach 1:
The patent modifies the chemical composition parameters by replacing epoxy resin with specific polyol combinations (polyether polyol, crystalline polyester polyol, amorphous polyester polyol, and acrylic polyol in specific ratios) and adjusting the NCO index to 0.8-1.2, which fundamentally changes the curing mechanism from epoxy-based to polyurethane-based, thereby achieving both moisture resistance and flexibility
Solution Approach 2:
The patent creates a composite adhesive system combining multiple polyol types (polyether, crystalline polyester, amorphous polyester, and acrylic polyols) with polyisocyanate to form a polyurethane-based composite material that integrates water resistance, flexibility, and adhesion properties that individual materials cannot achieve alone
2Reliability
If a moisture- and heat-resistant hot-melt adhesive composition containing epoxy resin is used, then moisture and heat resistance are improved, but flexibility becomes insufficient
Solution Approach 1:
The patent changes the fundamental chemical parameter by eliminating epoxy resin and using polyols with specific glass transition temperatures and molecular weights, creating a polyurethane system that inherently provides both moisture resistance and the flexibility required for optical element lamination
Solution Approach 2:
The patent assigns different functional roles to different polyol components: polyether polyol provides flexibility and low-temperature performance, crystalline polyester polyol provides strength and water resistance, amorphous polyester polyol provides adhesion, and acrylic polyol provides impact resistance, creating a locally optimized composite system
3Temperature
If conventional hot-melt adhesives are used for lamination, then low-temperature bonding is achieved, but fast-curing properties are insufficient
Solution Approach 1:
The patent introduces a specific curing catalyst (organometallic compound or organic compound with specific functional groups) as an intermediary that accelerates the polyurethane curing reaction, enabling fast curing at low temperatures by facilitating the reaction between isocyanate groups and moisture without requiring high thermal energy
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 exhibits superior water resistance, fast-curing properties, flexibility, adhesion to various substrates, workability, and shape retention, making it suitable for bonding fibers, lamination of construction materials, and optical elements, with optional drop impact resistance when an acrylic resin is included.
Implementation Method 1
a moisture-curable polyurethane hot-melt resin composition containing an isocyanate-containing urethane prepolymer (i) that is a reaction product of polyols (A) including a polyether polyol (A-1), a crystalline polyester polyol (A-2), an amorphous polyester polyol (A-3), and an acrylic polyol (A-4) with a polyisocyanate (B); and a curing catalyst (ii)
Data Source
AI summary
An object of the present invention is to provide a moisture-curable polyurethane hot-melt resin composition with superior properties such as water resistance, fast-curing properties, and flexibility. The present invention provides a moisture-curable polyurethane hot-melt resin composition containing an isocyanate-containing urethane prepolymer (i) that is a reaction product of polyols (A) including a polyether polyol (A-1), a crystalline polyester polyol (A-2), an amorphous polyester polyol (A-3), and an acrylic polyol (A-4) with a polyisocyanate (B); and a curing catalyst (ii) represented by general formula (1) below, and also provides an adhesive and article produced using the resin composition. The adhesive produced using the moisture-curable polyurethane hot-melt resin composition according to the present invention is suitable not only for the bonding of fibers and the lamination of construction materials, but also for the lamination of optical elements.