Formaldehyde-Free Melamine Tanning for Leather

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Solution Overview

Problem

Existing leather tanning processes often rely on formaldehyde-based agents to achieve soft and strong leather, which can release formaldehyde post-processing, posing environmental concerns and health risks, and fail to provide optimal surface selectivity.

Innovation Solution

A method involving the use of a formaldehyde-free melamine formulation with polyhydric alcohols such as ethylene glycol and glycerin, applied in solvents to treat animal skins or semi-finished products, ensuring minimal formaldehyde content and improved leather properties like softness, strength, and surface selectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If formaldehyde-based tanning agents are used to achieve soft and strong leather, then leather softness and strength are improved, but formaldehyde release occurs post-processing causing environmental and health concerns

Engineering Contradiction:
Improveleather strengthVSAvoidformaldehyde release
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes formaldehyde from the tanning agent formulation, using melamine alone or with polyhydric alcohols instead of formaldehyde-based resins. This eliminates the harmful formaldehyde release while maintaining the tanning effectiveness and leather strength.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical composition parameters of the tanning agent by substituting formaldehyde with melamine and polyhydric alcohols. This parameter change maintains the crosslinking and tanning functionality while eliminating formaldehyde release, thus resolving the contradiction between strength and harmful emissions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If melamine-formaldehyde condensates are used as water-soluble tanning agents, then tanning effectiveness is improved, but continuous formaldehyde release occurs long after processing

Engineering Contradiction:
Improvetanning effectivenessVSAvoidcontinuous formaldehyde release
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes formaldehyde from the melamine-based tanning system, using melamine alone or combined with polyhydric alcohols. This extraction eliminates the continuous formaldehyde release problem while preserving the water solubility and tanning effectiveness of the melamine formulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses melamine and polyhydric alcohols as stable, non-formaldehyde releasing tanning agents that provide effective tanning without long-term harmful emissions, replacing the problematic melamine-formaldehyde condensates.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Shape

If resin tanning agents with high molecular weight melamine resins are used, then leather fullness is improved, but formaldehyde split off or hemiaminals are blamed for tanning effect and softness

Engineering Contradiction:
Improveleather fullnessVSAvoidformaldehyde and hemiaminals
Core Design Contradiction:
ShapeVSObject-generated harmful factors

Solution Approach 1:

The patent extracts formaldehyde and hemiaminals from the tanning system by using melamine alone or with polyhydric alcohols instead of formaldehyde-reacted melamine resins. This eliminates the harmful substances while maintaining the molecular weight and fullness properties of the leather.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical structure parameters by using melamine with polyhydric alcohols to achieve the desired molecular weight and fullness without formaldehyde content, thus resolving the contradiction between fullness and harmful substance generation.

Inventive Principle:
Principle #35Parameter changes

4Strength

If conventional tanning agents are used to achieve sufficient softness and strength, then leather mechanical properties are improved, but surface selectivity is not optimized

Engineering Contradiction:
Improveleather strengthVSAvoidsurface selectivity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent optimizes the surface selectivity parameter by adjusting the formulation of melamine with specific polyhydric alcohols and solvents. This parameter optimization achieves both sufficient strength and improved surface selectivity, resolving the contradiction between mechanical strength and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

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 method produces leather that is soft, strong, and full, with enhanced surface selectivity, while maintaining negligible formaldehyde levels, suitable for applications in furniture and clothing, and offering improved grain resistance and color intensity.

Implementation Method 1

a method for producing leather, characterized in that animal skins or semi-finished products are treated with a formaldehyde-free formulation of melamine in a solvent or solvent mixture comprising at least one polyhydric alcohol

Methodology Applied
Scientific EffectTanning:

Data Source

PatentEP2205768B1Method for producing leather
Publication Date: 2011.08.24 BASF SE

AI summary

A method for producing leather, characterized in that animal skins or semifinished products are treated with a formaldehyde-free formulation of melamine in a solvent or solvent mixture, comprising at least one multivalent alcohol.