Artificial Leather Coating Without Solvent Drying or Crosslinking

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Solution Overview

Problem

The production of artificial leather using urethane resin is complicated and requires the use of organic solvents and crosslinking agents, making it difficult to achieve a practically usable product in a short time due to the need for prolonged drying and crosslinking steps.

Innovation Solution

A method involving a moisture-curing urethane hot-melt resin composition without organic solvents or crosslinking agents, where a urethane prepolymer with isocyanate groups is applied to a substrate, forming a unified intermediate and skin layer, eliminating the need for drying and crosslinking steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a crosslinking agent and organic solvent are used to simplify the process into a unified layer formation, then the process complexity is reduced, but the production time is prolonged due to required crosslinking and drying steps

Engineering Contradiction:
Improveprocess complexityVSAvoidproduction time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent removes the crosslinking agent from the resin composition, extracting the harmful element that causes prolonged crosslinking steps. By using a moisture-curing urethane hot-melt resin without crosslinking agents, the process eliminates the need for separate crosslinking steps while maintaining unified layer formation, thus reducing production time without increasing complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical composition parameters of the resin by specifying isocyanate group content (1.1-5.0 mass%) and hydroxyl group content (0.1-1.0 mass%), creating a self-curing system that operates under different chemical parameters than traditional crosslinking systems, enabling faster curing without prolonged crosslinking steps

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If organic solvents are used in the resin composition, then the resin can be applied and processed, but drying steps are required which extend production time

Engineering Contradiction:
Improveresin processabilityVSAvoiddrying time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent changes the physical state parameter of the resin from solvent-based to hot-melt form, eliminating the need for drying steps. The resin is applied in a melted state and cured through moisture reaction, completely removing the drying step from the process while maintaining ease of application

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and removes organic solvents from the resin composition entirely, using a solvent-free hot-melt system. This eliminates the harmful drying step required to remove solvents, reducing production time while maintaining resin processability through controlled melting and application

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If a crosslinking agent is used to form the cured product layer, then the layer structure is established, but the crosslinking step requires prolonged time

Engineering Contradiction:
Improvelayer structure stabilityVSAvoidcrosslinking time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent removes crosslinking agents from the system and replaces them with a moisture-curing mechanism inherent to the urethane prepolymer. The isocyanate groups react with atmospheric moisture to form the cured network structure, eliminating the need for separate crosslinking steps and significantly reducing the time required to establish layer structure

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The resin composition is designed to self-cure through reaction with ambient moisture, without requiring external crosslinking agents or additional chemical additives. The moisture-curing urethane hot-melt resin automatically forms the crosslinked network structure through its own chemical groups, reducing process time while maintaining structural stability

Inventive Principle:
Principle #25Self-service

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

This approach reduces production time, eliminates the use of organic solvents and crosslinking agents, and simplifies the process while achieving a high-quality artificial leather with excellent texture, mechanical strength, and peel strength.

Implementation Method 1

a cured product layer of a moisture-curing urethane hot-melt resin composition

Methodology Applied
Scientific EffectMoisture-curing: Chemical Bonding

Data Source

PatentEP3666971B1Method for manufacturing artificial leather
Publication Date: 2024.04.17 DIC CORP

AI summary

An object to be achieved by the present invention is to provide a method for producing an artificial leather on a practically usable level without using an organic solvent and without requiring a crosslinking step for a crosslinking agent. The present invention provides a method for producing an artificial leather having a cured product layer of a moisture-curing urethane hot-melt resin composition, wherein the moisture-curing urethane hot-melt resin composition contains a urethane prepolymer having an isocyanate group and does not contain a crosslinking agent having a hydroxyl group and/or an amino group, the method including applying the moisture-curing urethane hot-melt resin composition to a substrate at a coating weight of 0.03 to 0.5 kg/m2 so as to form a cured product layer of the moisture-curing urethane hot-melt resin composition.