Co-extruded Polyolefin Adhesive Layer for Polyurethane Foam Bonding

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Solution Overview

Problem

Existing methods for adhering polyolefins to polyurethane foams are complex, costly, and often result in low adhesion strength due to the non-polar nature of polyolefins, with limitations including film lamination processes, use of expensive modifiers, and volatile solvents in primer applications.

Innovation Solution

Co-extrusion of polyolefins with adhesive layers, specifically using ethylene vinyl acetate (EVA) copolymers with varying vinyl acetate content and surface roughness, to create a polar surface for enhanced adhesion in a single, simplified step.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polyolefins are used for adhesion to PU foams, then chemical resistance and low density are improved, but adhesion strength deteriorates due to non-polar characteristics

Engineering Contradiction:

Improveadhesion strengthVSAvoidnon-polar characteristic

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent uses composite materials by combining polyolefin with adhesive layers containing polar components (such as polyvinylidene fluoride, polyacrylonitrile, or carboxymethyl cellulose) to create a multi-layer structure that exhibits both the desired adhesion strength and the chemical resistance of polyolefins

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the surface parameters of polyolefin by applying adhesive layers with different polarities and surface energies, thereby modifying the adhesion characteristics without changing the bulk properties of the polyolefin material

Inventive Principle:

Principle #35Parameter changes

2Strength

If film lamination process is used to adhere polyolefins to PU foams, then adhesion is improved, but process complexity increases due to multiple steps

Engineering Contradiction:

Improveadhesion strengthVSAvoidprocess complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent merges the adhesion function into the polyolefin structure itself by co-extruding or coating adhesive layers during the same manufacturing process, eliminating the need for separate lamination steps and reducing overall process complexity

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If adhesive intermediate film is used in doubling process, then adhesion between polyolefin and PU foam is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveadhesion strengthVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent extracts the adhesive function from a separate intermediate film and integrates it directly into the polyolefin layer through co-extrusion or coating techniques, thereby simplifying the manufacturing process while maintaining adhesion performance

Inventive Principle:

Principle #2Taking out (Extraction)

4Strength

If expensive modifiers like chlorinated polymers or EPDM are added to polyolefin, then adhesion to PU foam is improved, but material cost increases

Engineering Contradiction:

Improveadhesion strengthVSAvoidmaterial cost

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent uses cost-effective adhesive layers such as carboxymethyl cellulose or starch-based adhesives that provide the necessary adhesion strength without requiring expensive modifiers like chlorinated polymers or EPDM

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

5Strength

If curable primers are applied to polyolefin surface, then adhesion to PU foam is improved, but process complexity and environmental harm increase due to solvents and UV curing

Engineering Contradiction:

Improveadhesion strengthVSAvoidsolvents and volatiles

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful solvents and curing agents from the adhesive system by using water-based or solvent-free adhesive layers that achieve adhesion through simple drying or thermal treatment, eliminating environmental and health hazards associated with traditional primers

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 co-extruded polyolefin-adhesive structure achieves significantly stronger adhesion to polyurethane foams, overcoming previous limitations with improved adhesion forces and reduced complexity, making the process more economical and environmentally friendly.

Implementation Method 1

a polar surface is imparted to the obtained adhesive polyolefin

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11319469B2Method for preparing an adhesive polyolefin, adhesive polyolefin, use thereof, and manufactured article

Publication Date: 2022.05.03 BRASKEM SA

AI summary

The present invention refers to co-extrusion of one or more polyolefins with one or more adhesive layers to improve the adhesiveness of the polyolefins in metal, epoxy resin, glass, ceramics, paper, wood, thermoplastic resin, fabric, non-woven fabric, varnishes and formica.More specifically, the present invention refers to a method of co-extruding at least one polyolefin with an adhesive layer, thereby enhancing the adhesion properties of the polyolefin, particularly in polyurethane foams such that a polar surface is imparted to the obtained adhesived polyolefin.