Pre-pasted Wall Covering PVA Adhesive Layer

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Solution Overview

Problem

Existing wall coverings face difficulties with adhesives that are complex, expensive, environmentally hazardous, and cause delamination and tearing during removal, with issues of incomplete stripability and high production costs due to the use of super absorbent polymers and other hazardous ingredients.

Innovation Solution

A pre-pasted wall covering with a polyvinyl alcohol polymer adhesive layer applied separately on the substrate, which is cold water soluble and prevents penetration into the substrate, allowing for easy reactivation and improved stripability without delamination, using either lamination or coating methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If pre-pasted starch paper or super absorbent polymers are used for adhesive layer, then adhesion to wall is improved, but reactivation time increases to tens of minutes and production costs increase

Engineering Contradiction:

ImproveadhesionVSAvoidreactivation time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive layer by using polyvinyl alcohol (PVA) instead of traditional starch or super absorbent polymers. This parameter change enables the adhesive to reactivate quickly with water while maintaining strong adhesion, thus resolving the contradiction between adhesion strength and reactivation time

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a disposable adhesive layer made of PVA that is designed to be applied once and removed cleanly without residue. This approach reduces production costs compared to expensive SAP-based adhesives while maintaining effective adhesion and quick reactivation properties

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Strength

If very high water-retention polymers are used in adhesive layer, then adhesion is improved, but production costs increase due to production difficulties and converting issues

Engineering Contradiction:

ImproveadhesionVSAvoidproduction ease

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces expensive and difficult-to-manufacture super absorbent polymers with a simpler, more cost-effective PVA-based adhesive layer. This substitution maintains adhesion performance while significantly improving ease of manufacture and converting processes

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the polymer type parameter from high water-retention SAPs to PVA, which has different but sufficient water retention properties for wallpaper application. This parameter change simplifies production processes and reduces manufacturing difficulties

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If adhesive layer is applied separately on substrate, then blocking phenomenon is prevented, but manufacturing process complexity increases

Engineering Contradiction:

Improveblocking phenomenonVSAvoidmanufacturing process complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the adhesive layer from the substrate by applying it separately as a distinct coating layer. This segmentation prevents the blocking phenomenon where adhesive activates during printing, while the manufacturing process remains relatively simple through standard coating techniques

Inventive Principle:

Principle #1Segmentation

4Strength

If existing pre-pasted solutions with hazardous ingredients are used, then adhesion is achieved, but environmental and health hazards increase

Engineering Contradiction:

ImproveadhesionVSAvoidenvironmental and health hazards

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent converts the traditional approach of using hazardous adhesives into a beneficial solution by employing PVA, which is non-toxic and environmentally friendly. This maintains adhesion performance while eliminating environmental and health hazards associated with REACH-certified ingredients

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution provides easy reactivation, good adhesion, and improved stripability without delamination or tearing, while being environmentally friendly and cost-effective, using only REACH-certified ingredients, and preventing the blocking phenomenon during production and use.

Implementation Method 1

The polyvinyl alcohol polymer is preferably cold water soluble

Methodology Applied

Scientific EffectCold water solubility: Solvation

Implementation Method 2

arranging on the back side of the substrate an adhesive layer which includes a polyvinyl alcohol polymer... so as to avoid that water used for remoistening the bottom side is absorbed by the paper

Methodology Applied

Scientific EffectWater barrier: Physical Containment

Data Source

PatentUS20220267648A1Pre-pasted wall cover and a method of producing the same

Publication Date: 2022.08.25 AHLSTROM OYJ

AI summary

A wall covering comprising a planar substrate having a front and a back facing opposite the front and an adhesive layer that covers the back of the substrate. The adhesive layer includes a separate polymer layer, formed by a polyvinyl alcohol polymer. Wall covering for example in the form of a pre-pasted paper is readily reactivated when wet, and exhibits no blocking, while having properties of sliding, adhesion, and stripability.