Leather-Like Sheet Surface Skin with UV-Moisture Dual Curing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional leather-like sheets face issues with fuzz generation and surface tack due to incomplete curing of non-solvent type hot-melt urethane resins, leading to poor surface quality and limited application range, especially in low-temperature environments.
Innovation Solution
A polyurethane hot-melt composition is developed with a urethane prepolymer containing isocyanate groups and (meth)acrylate, which undergoes both moisture and ultraviolet curing reactions, ensuring complete curing and suppressing fuzz generation, comprising 100 parts of urethane prepolymer, 5-40 parts of coloring agent, and 0.5-5 parts of photopolymerization initiator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-solvent type hot-melt urethane resin is used to form surface skin layer, then environmental friendliness and application range are improved, but curing completeness is insufficient leading to fuzz generation and poor surface quality
Solution Approach 1:
The patent introduces polymerizable unsaturated bonds into the urethane resin molecule structure, enabling the resin to undergo photopolymerization curing. This chemical parameter change allows the resin to achieve complete curing through UV irradiation, eliminating surface tack and fuzz generation while maintaining environmental friendliness by using non-solvent type hot-melt urethane resin
Solution Approach 2:
The patent creates a composite material system combining urethane resin with polymerizable unsaturated bonds and photopolymerization initiators. This composite enables dual functionality: the urethane resin provides adhesion and flexibility, while the photopolymerizable components enable complete curing through UV light, resolving the contradiction between environmental friendliness and surface quality
2Productivity
If winding into roll is performed before complete curing, then manufacturing efficiency is improved, but surface tack causes fuzz generation and deteriorates surface grade
Solution Approach 1:
The patent applies photopolymerization initiator and introduces polymerizable unsaturated bonds into the resin before the winding process. This preliminary action enables the resin to be fully cured by UV irradiation during or after winding, eliminating surface tack before the material contacts itself in the rolled state, thus preventing fuzz generation while maintaining manufacturing efficiency
3Object-affected harmful factors
If aqueous polyurethane resin is used instead of organic solvent type, then environmental impact is reduced, but water resistance and durability deteriorate
Solution Approach 1:
The patent fundamentally changes the chemical structure of the urethane resin by introducing polymerizable unsaturated bonds, enabling the use of non-solvent type hot-melt resin that can be fully cured through photopolymerization. This structural modification eliminates the need for organic solvents or water, while the complete curing forms a cross-linked network that provides excellent water resistance and durability
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 solution results in a leather-like sheet with excellent surface grade, suppleness, durability, and bending resistance, suitable for various applications including footwear and furniture, while maintaining mechanical strength and adhesiveness.
Implementation Method 1
a polyurethane hot-melt composition containing 100 parts by mass of a urethane prepolymer (A), 5 parts by mass to 40 parts by mass of a coloring agent (B) containing a polyol as a vehicle, 5 parts by mass to 50 parts by mass of multifunctional (meth)acrylate (C), and 0.5 parts by mass to 5 parts by mass of a photopolymerization initiator (D)
Implementation Method 2
a hot-melt urethane resin whose application to the surface skin layer of the leather-like sheet is known into broad use as an adhesive, a coating agent and the like for construction materials and for fibers, etc., as an environmental responsive high added value product replacing the conventional solvent type resin and an aqueous resin
Data Source
Figure 1~3
AI summary
A leather-like sheet (1) is provided having at least a substrate layer (11) and a surface skin layer (12) in which surface skin layer (12) is composed of a cross-linked product of a polyurethane hot-melt composition containing 100 parts by mass of a urethane prepolymer (A), 5 parts by mass to 40 parts by mass of a coloring agent (B) containing a polyol as a vehicle, 5 parts by mass to 50 parts by mass of multi-functional (meth)acrylate (C), and 0.5 parts by mass to 5 parts by mass of a photopolymerization initiator (D), wherein the urethane prepolymer (A) can be obtained by reacting 5% to 50% of the number of isocyanate groups in a urethane prepolymer containing isocyanate groups that is obtained by reacting a polyol (a1) containing 40% by mass or more of polytetramethylene glycol and a polyisocyanate (a2) with a (meth)acrylate containing a hydroxyl group. Leather-like sheet (1) has an excellent surface grade while maintaining excellent suppleness and bending resistance.