Embossable non-solvent PU sheet, a laminate and a synthetic leather comprising the same
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Solution Overview
Problem
Existing non-solvent polyurethane sheets used in synthetic leather manufacturing are unable to achieve high texture duplication and clear embossing patterns, especially at lower temperatures, limiting the quality and performance of the final product.
Innovation Solution
A non-solvent polyurethane sheet composed of a specific polyol component with a functionality range of 1.5 to 2.5 and an isocyanate component, along with optional additives, is used to create a base coat layer that enhances texture duplication, peel strength, and curing properties, allowing embossing at lower temperatures (160° C. to 175° C).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If normal thermosetting/cross-linked PU system is used, then the synthetic leather has good basic properties, but it is impossible to be embossed even under very high embossing temperature
Solution Approach 1:
The invention changes the chemical composition parameters of the polyol component, specifically using polyols with functionality of 2.3 or higher (such as glycerol, trimethylolpropane, pentaerythritol) and controlling the average functionality to 2.05-2.30. This parameter change enables the PU sheet to become embossable at lower temperatures while maintaining good basic properties
Solution Approach 2:
The invention creates a composite polyol system by combining polyols with different functionalities (mixing polyols with functionality 2.3 or higher with other polyols). This composite approach allows achieving both embossability and structural integrity, resolving the contradiction between embossing capability and basic material properties
2Manufacturing precision
If polyol with higher functionality is used to improve embossability, then the texture duplicate property improves, but the curing property and flexing endurance may deteriorate
Solution Approach 1:
The invention precisely controls the average functionality parameter of the polyol component within the range of 2.05-2.30, and controls the NCO-OH ratio within 0.95-1.05. This precise parameter control achieves optimal balance between texture duplicate (>50%) and reliable curing properties with good flexing endurance
Solution Approach 2:
The invention uses feedback control by measuring and adjusting the average functionality of the polyol mixture and the NCO-OH ratio to ensure they fall within the optimal ranges. This feedback mechanism guarantees consistent texture duplicate and curing properties across production batches
3Manufacturing precision
If high embossing temperature is used to achieve embossing pattern, then the embossing can be obtained, but the energy consumption increases and the base coat layer properties deteriorate
Solution Approach 1:
The invention changes the chemical composition to enable embossing at lower temperatures (100-180°C) by using polyols with functionality 2.3 or higher. This parameter change reduces energy consumption significantly compared to conventional high-temperature embossing while achieving clear embossing patterns
Solution Approach 2:
The invention replaces the thermal-mechanical embossing system (high temperature + pressure) with a chemically-enabled lower-temperature system. The specific polyol composition allows the material to become sufficiently soft and moldable at lower temperatures, substituting the need for high thermal energy with chemical composition optimization
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 synthetic leather with improved texture duplication, peel strength, and flexing endurance, while enabling sharp and clear embossing patterns without the need for high temperatures.
Implementation Method 1
non-solvent polyurethane system comprising a polyol component (a) and an isocyanate component (b)
Data Source
AI summary
Described herein is an embossable non-solvent polyurethane sheet, which is formed from a non-solvent polyurethane system including a polyol component (a) and an isocyanate component (b), where the polyol component (a) includes (a-1) at least one polyol having a functionality in a range of from 1.5 to 2.5; and (a-2) optionally at least one polyol having a functionality in a range of 2.7 to 3.5, wherein an amount of the at least one polyol (a-2) is ≤6 wt %, based on a total weight of the polyol component (a), and wherein the polyol component (a) has an average functionality of from 1.5 to 2.1. Also described herein are a laminate including the sheet and a synthetic leather including the sheet. Also described herein are a method of using the sheet, a method of using the laminate, and a method of using the synthetic leather.