Method for manufacturing artificial leather

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Solution Overview

Problem

The production of artificial leather using urethane resin is complex and requires the use of organic solvents and crosslinking agents, which are subject to strict regulations and prolong the production time.

Innovation Solution

A method involving a moisture-curing urethane hot-melt resin composition without a crosslinking agent, applied at a specific coating weight to form a unified cured product layer, eliminating the need for drying and crosslinking steps, and using a urethane prepolymer with an isocyanate group.

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 number of production steps 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 extracts and removes the crosslinking agent from the resin composition, using a moisture-curing urethane system that cures without additional crosslinking chemicals. This eliminates the crosslinking step while maintaining the unified layer structure, thereby reducing production time without increasing process complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the curing mechanism from chemical crosslinking to moisture-curing, and from solvent-based to hot-melt application. These parameter changes eliminate the need for separate crosslinking and drying steps, resolving the contradiction between process simplification and production time

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If organic solvents and crosslinking agents are used in the resin composition, then the resin can be applied and cured, but the production process becomes subject to strict environmental regulations and requires additional processing steps

Engineering Contradiction:
Improveresin applicabilityVSAvoidenvironmental regulation impact
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes both the organic solvent and crosslinking agent from the resin composition. The resulting moisture-curing urethane hot-melt resin can be applied without solvents and cures without crosslinking agents, eliminating environmental harmful factors while maintaining ease of manufacture through simple application and natural curing processes

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the resin from a solvent-based system to a hot-melt system, and from a crosslinking-based cure to a moisture-curing system. These parameter changes eliminate environmental regulations concerns while preserving the resin's applicability and curing capability

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If multiple separate layers (intermediate layer and skin layer) are formed with separate drying steps, then each layer can be optimized independently, but the production process becomes very complicated and time-consuming

Engineering Contradiction:
Improvelayer optimizationVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the intermediate layer and skin layer into a single unified cured product layer formed from one resin composition application. This consolidation maintains sufficient layer optimization through the resin's inherent properties while dramatically simplifying the production process by eliminating multiple application and drying steps

Inventive Principle:
Principle #5Merging (Combining)

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 simplifies the process by unifying the intermediate and skin layers, resulting in an environmentally friendly and practically usable artificial leather with improved mechanical strength and texture.

Implementation Method 1

a mixture solution containing a polyurethane resin solution and a polyisocyanate crosslinking agent is applied onto release paper and dried, and the resultant film immediately after being dried is heat-bonded to a fabric base

Methodology Applied
Scientific EffectMoisture-curing reaction: Chemical Bonding

Implementation Method 2

the intermediate layer and the skin layer are unified into one layer using the cured product layer of the moisture-curing urethane hot-melt resin composition

Methodology Applied
Scientific EffectHot-melt bonding: Melting

Data Source

PatentUS11634530B2Method for manufacturing artificial leather
Publication Date: 2023.04.25 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.