Cellulose Derivative Coating for Grease Barrier and Flexibility

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Solution Overview

Problem

Conventional coatings for packaging materials, particularly those used for food and liquids, face challenges in providing effective grease barriers while maintaining flexibility and resistance to cracking during folding, and they often hinder recyclability due to the use of petroleum-based chemicals and non-renewable sources.

Innovation Solution

A two-layered coating structure comprising a water-soluble cellulose derivative and a plasticizer applied directly on a sheet-like substrate made of cellulosic or lignocellulosic fibers, which acts as a grease barrier, is biodegradable, and repulpable, reducing the need for non-renewable components and minimizing cracking tendencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional petroleum-based polymers are used in coating compositions, then grease barrier properties and resistance to cracking are improved, but environmental sustainability deteriorates

Engineering Contradiction:
Improvebarrier properties and crack resistanceVSAvoidenvironmental sustainability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by replacing petroleum-based polymers with water-soluble cellulose derivatives, specifically using alkyl celluloses, hydroxyalkyl alkyl celluloses, or hydroxyalkyl celluloses. This parameter change maintains the coating's functional properties while improving environmental sustainability and biodegradability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite coating system combining water-soluble cellulose derivatives with plasticizers. This composite material approach allows the coating to achieve both grease barrier properties and flexibility, preventing cracking while being environmentally friendly and biodegradable.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If conventional bio-based components such as starch are used in coating formulations, then renewable resource usage is improved, but coating flexibility and crack resistance deteriorate

Engineering Contradiction:
Improverenewable resource usageVSAvoidcoating flexibility and crack resistance
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent changes the type of bio-based component from conventional starch to water-soluble cellulose derivatives (alkyl celluloses, hydroxyalkyl alkyl celluloses, or hydroxyalkyl celluloses). This parameter change maintains renewable resource usage while significantly improving coating flexibility and preventing brittleness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies different functional components at different levels: the cellulose derivative provides the flexible matrix while the plasticizer specifically targets the flexibility and crack resistance properties. This local quality approach ensures both renewable resource usage and coating flexibility are achieved.

Inventive Principle:
Principle #3Local quality

3Reliability

If traditional barrier coatings are applied on paper and board, then grease barrier properties are improved, but recyclability and repulpability deteriorate

Engineering Contradiction:
Improvegrease barrier propertiesVSAvoidrecyclability and repulpability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition to water-soluble cellulose derivatives, which fundamentally alters the coating's interaction with water during the repulping process. This parameter change enables the coating to dissolve or disperse in water, allowing paper and board to be easily repulped and recycled without special process arrangements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention effectively extracts the barrier function from the coating matrix, allowing the coating to provide grease barrier properties while being separable from the paper substrate during repulping. The water-soluble nature of the cellulose derivative allows the coating to be taken out during the recycling process, enabling easy repulpability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 coating structure effectively prevents grease and mineral oil leakage, maintains flexibility to avoid cracking, and supports recyclability, making it suitable for foodservice packaging while being environmentally friendly.

Implementation Method 1

a barrier coating layer comprising at least one water-soluble cellulose derivative selected from alkyl celluloses, hydroxyalkyl alkyl celluloses, hydroxyalkyl celluloses

Methodology Applied
Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 2

at least the first coating layer or the second coating layer is a barrier coating layer comprising at least one water-soluble cellulose derivative

Methodology Applied
Scientific EffectPhysical barrier formation: Coatings

Implementation Method 3

a plasticizer

Methodology Applied
Scientific EffectPlasticization:

Implementation Method 4

at least one water-soluble cellulose derivative selected from alkyl celluloses, hydroxyalkyl alkyl celluloses, hydroxyalkyl celluloses

Methodology Applied
Scientific EffectSolvation: Solvation

Data Source

PatentUS20230220628A1Coating structure, sheet-like product and its use
Publication Date: 2023.07.13 KEMIRA OY

AI summary

The present invention relates to a coating structure for a sheet-like substrate comprising cellulosic fibres. The coating structure comprises at least a first coating layer and a second coating layer, where the second coating layer is arranged in a direct contact with the first coating layer. At least the first coating layer or the second coating layer is a barrier coating layer comprising at least one water-soluble cellulose derivative selected from alkyl celluloses, hydroxyalkyl alkyl celluloses, hydroxyalkyl celluloses and any of their mixtures, and a plasticizer.