Solventless Adhesive for High-Speed Coating Multilayer Film

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Solution Overview

Problem

Conventional solventless adhesives used in multi-layered films for packaging containers exhibit low laminate strength and impact resistance, especially when applied at high coating speeds, and are not environmentally friendly due to the use of VOCs and solvents.

Innovation Solution

A multi-layered film is developed using a solventless adhesive composed of a polyester-based main agent and aliphatic and alicyclic isocyanate curing agents, with specific viscosity and molecular weight ranges to ensure high-speed coating and improved laminate strength and impact resistance, while being environmentally friendly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a polyether-based solventless adhesive is used, then high-speed coating property is improved, but laminate strength and impact resistance deteriorate

Engineering Contradiction:
Improvecoating speedVSAvoidlaminate strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive by using a polyester-based main agent with specific molecular weight range (500-2000) and combining it with a polyisocyanate curing agent. This parameter optimization enables the adhesive to maintain appropriate viscosity at high coating speeds while achieving sufficient laminate strength and impact resistance after curing.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a conventional solventless adhesive is used, then environmental friendliness is improved by removing VOCs, but laminate strength and impact resistance deteriorate

Engineering Contradiction:
ImproveVOC emissionsVSAvoidlaminate strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent creates a composite adhesive system by combining a polyester-based main agent with a polyisocyanate curing agent. This composite formulation eliminates VOCs by being solventless while the chemical reaction between the two components forms a strong crosslinked network that provides both laminate strength and impact resistance.

Inventive Principle:
Principle #40Composite materials

3Productivity

If coating speed is increased to 150m/min, then productivity is improved, but adhesive wetting becomes insufficient causing defective appearance and reduced laminate strength

Engineering Contradiction:
Improvecoating speedVSAvoidadhesive wetting quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the viscosity parameter of the adhesive by selecting a polyester main agent with molecular weight of 500-2000. This viscosity optimization ensures that the adhesive can be applied at high speeds (150m/min) while still maintaining adequate wetting of the substrate, preventing defective appearance and ensuring proper adhesion.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If a solvent adhesive is used, then ease of application is improved, but environmental contamination increases due to solvent evaporation

Engineering Contradiction:
Improveadhesive applicationVSAvoidsolvent evaporation
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the solvent component from the adhesive formulation, transitioning from a solvent-based system to a solventless system. This extraction eliminates harmful solvent evaporation and VOC emissions while the adhesive remains applicable through the chemical reactivity of the polyester and polyisocyanate components.

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 film achieves excellent laminate strength and impact resistance even at high coating speeds, reducing environmental impact by eliminating VOCs and solvent use, making it suitable for packaging liquids like detergents and beverages.

Implementation Method 1

a multi-layered film which is formed by laminating at least an inner-layer film, an adhesive layer and an outer-layer film in order, wherein the adhesive layer is formed of a solventless adhesive which contains a polyester-based main agent and a curing agent made of aliphatic isocyanate and alicyclic isocyanate

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP2316642B1Multilayer film using solvent-free adhesive, method for producing same and packaging container
Publication Date: 2015.05.20 TOYO SEIKAN KAISHA LTD
  • EP2316642B1 patent drawingFigure 1
  • EP2316642B1 patent drawingFigure 2
  • EP2316642B1 patent drawingFigure 3

AI summary

A multilayered film which is formed using a solventless adhesive, can obviate wetting deficiency even when the film is manufactured by applying the solventless adhesive to a film by coating at a high speed, exhibits the excellent laminate strength and the excellent impact resistance after a liquid content is filled into a packaging container and exhibits excellent environment friendliness, a method of manufacturing the multilayered film, and a packaging container which uses the multilayered film are provided. In the multilayered film which is formed by laminating at least an inner-layer film, an adhesive layer and an outer-layer film in order, the adhesive layer is formed of a solventless adhesive which contains apolyester-based main agent and a curing agent made of aliphatic isocyanate and alicyclic isocyanate.