Starch-Based Liquid Adhesive pH Control for Stability and Washability

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Solution Overview

Problem

Existing adhesives face challenges in providing a cohesive connection for a wide variety of materials, especially absorbent ones like paper, wood, and textiles, while maintaining stability and resistance to chemical and biological degradation, and ensuring easy washability and consumer acceptance.

Innovation Solution

A water-based liquid adhesive with a pH value between 3 and 6, comprising at least 15% starch derivatives, up to 30% mono-, di-, or trisaccharides, and polyvalent organic carboxylic acids, which ensures stability, adhesive strength, and easy washability without significant degradation or color change.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the adhesive is formulated with starch derivatives and sugar to be water-based and renewable, then environmental friendliness and health safety are improved, but the adhesive becomes prone to chemical and biological degradation over time

Engineering Contradiction:
Improveharmful degradation and color changeVSAvoidadhesive stability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies parameter changes by adjusting the pH value to an acidic range (3-6) and selecting specific acids with pKS1 values between 2.5-6.0. This chemical parameter modification stabilizes the starch-based adhesive against degradation while maintaining its renewable and water-based formulation, thus resolving the contradiction between environmental friendliness and stability.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the adhesive has strong bonding properties for absorbent materials, then adhesive strength is improved, but the adhesive becomes difficult to wash out of textiles

Engineering Contradiction:
Improveadhesive strengthVSAvoidwashability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent utilizes parameter changes by formulating the adhesive with an acidic pH (3-6) and specific starch derivatives that provide strong bonding to absorbent materials while maintaining water solubility. This allows the adhesive to be easily washed out with water-based cleaners even after setting, resolving the contradiction between bonding strength and washability.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the adhesive is liquid at 20°C for easy application, then ease of operation is improved, but the adhesive may be too viscous to flow properly

Engineering Contradiction:
ImproveapplicabilityVSAvoidflow rate
Core Design Contradiction:
Ease of operationVSSpeed

Solution Approach 1:

The patent applies parameter changes by controlling the viscosity through pH adjustment (3-6) and selecting appropriate starch derivatives and sugar ratios. This ensures the adhesive remains liquid at 20°C with optimal flow characteristics for easy application, resolving the contradiction between ease of application and proper flow.

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 adhesive maintains strong bonding properties over time, is resistant to chemical and biological degradation, and can be easily washed out of textiles, meeting consumer acceptance and environmental sustainability criteria.

Implementation Method 1

The liquid adhesive contains starch derivatives and a water retention agent... More recent developments aim to offer liquid, physically setting adhesive formulations

Methodology Applied
Scientific EffectGelation: Gel

Implementation Method 2

DE 100 03 642 A1 discloses an adhesive that is composed of compounds that are harmless to health... The adhesive described there essentially contains starch derivatives, sugar and water. According to DE 100 03 642 A1, dextrin is preferred as an acid-catalyzed degradation product of starch.

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP3094678B1Starch based liquid adhesive
Publication Date: 2017.11.22 HENKEL KGAA

AI summary

The invention relates to a water-based liquid glue and its use for bonding plastics, metals and open-pore and/or absorbent materials, in particular wood, paper, synthetic wool, cotton, felt and/or cork. The liquid glue contains starch derivatives and a water-retention agent, selected from mono-, di- and/or trisaccharides and/or sugar alcohols, the liquid glue having an acidic pH.