Release Layer Blend Reduces Unwinding Forces

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Solution Overview

Problem

Multilayer protective films experience high unwinding forces during automatic operations, which can deform and damage the film, especially at higher unwind speeds, due to high adhesion between layers in roll form.

Innovation Solution

The development of multilayer protective films incorporating a release layer blend comprising greater than 50 wt.% of an ethylene/alpha-olefin copolymer, a functionalized ethylene-based polymer grafted with ethylenically unsaturated carboxylic acids and derivatives, and 3 to 20 wt.% of an inorganic filler, which reduces unwinding forces while maintaining adhesion to surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the film is wound in self-adhesive roll form, then storage and handling are simplified, but unwinding forces become excessively high causing film deformation and damage

Engineering Contradiction:
Improveroll form storage and handlingVSAvoidunwinding force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The invention divides the roll structure into distinct functional layers: a release layer with low adhesion to the core, and a protective film layer with adhesion to the substrate. This segmentation allows the release layer to reduce unwinding forces while the protective film maintains its adhesive function, resolving the contradiction between easy roll handling and excessive unwinding force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The release layer acts as an intermediary between the roll core and the protective film. It provides a low-adhesion interface that reduces friction and unwinding forces during automatic operations, while still allowing the protective film to adhere properly to the substrate when applied. This intermediary layer resolves the contradiction by mediating between the need for roll stability and the need for low unwinding resistance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If adhesive layers are applied directly to the core, then strong adhesion is achieved, but unwinding forces increase and damage film integrity

Engineering Contradiction:
Improveadhesion strengthVSAvoidfilm integrity during unwinding
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention segments the adhesive function into two separate layers: a release layer with minimal adhesion to the core for easy unwinding, and a protective film layer with full adhesion capability to the substrate. This segmentation allows strong adhesion where needed while preventing excessive unwinding forces that would damage film integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The release layer serves as an intermediary that prevents direct high-adhesion contact between the protective film and the roll core. This intermediary layer reduces unwinding forces to levels that preserve film integrity, while the protective film maintains its adhesive strength when applied to the actual substrate.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If high unwind speeds are used in automatic operations, then productivity increases, but film deformation and damage occur due to high unwinding forces

Engineering Contradiction:
Improveunwind speedVSAvoidfilm deformation control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The release layer acts as an intermediary that reduces unwinding forces to acceptable levels, enabling high unwind speeds in automatic operations without causing film deformation or damage. This allows productivity to increase while maintaining manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the adhesion parameter of the release layer to be low, which directly reduces unwinding forces. This parameter change enables high unwind speeds to be achieved without exceeding the film's deformation threshold, thus maintaining manufacturing precision while increasing productivity.

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 solution effectively reduces unwinding forces and noise, preserving the adhesion of the adhesive layer and preventing deformation, thus ensuring the integrity of the film during unwinding and application.

Implementation Method 1

the films tend to have high adhesion to itself, which can translate into very high unwinding forces during an unwinding operation

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a functionalized ethylene-based polymer grafted with ethylenically unsaturated carboxylic acids and acids derivatives

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3070134B1Protective films, blends, and methods of making thereof
Publication Date: 2021.03.03 DOW GLOBAL TECHNOLOGIES LLC
  • EP3070134B1 patent drawingFigure 1
  • EP3070134B1 patent drawingFigure 2
  • EP3070134B1 patent drawing

AI summary

A blend suitable for use in a release layer of a multilayer protective film. The blends comprise greater than 50 wt.% of an ethylene/alpha-olefin copolymer, a functionalized ethylene-based polymer, and an inorganic filler.