Linerless Label Adhesive Composition Blocking Prevention

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Solution Overview

Problem

Existing adhesive compositions for labels require release papers or films to prevent blocking, which incur additional costs and material usage, and existing solutions that eliminate these require high temperatures and pressures for activation.

Innovation Solution

An aqueous adhesive composition combining acrylate polymers with a glass transition temperature between +50°C to +90°C and amorphous polyurethane or polyurethane-polyurea polymers with a glass transition temperature between −50°C to +10°C, allowing for the formation of heat-activated adhesive layers that prevent blocking at high winding tensions and temperatures up to 50°C without the need for release papers or films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If release paper or film is used to prevent blocking, then blocking prevention is improved, but material costs and device complexity increase

Engineering Contradiction:
Improveblocking preventionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the release paper or film component from the label structure by developing an adhesive composition that inherently prevents blocking through its specific polymer formulation, thereby simplifying the overall structure while maintaining blocking prevention functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the parameter of glass transition temperature by combining polymers with Tg>+50°C and Tg<+10°C to create an adhesive that remains non-tacky at room temperature but becomes activatable at elevated temperatures, eliminating the need for release papers

Inventive Principle:
Principle #35Parameter changes

2Reliability

If release paper or film is used to prevent blocking, then blocking prevention is improved, but material costs increase

Engineering Contradiction:
Improveblocking preventionVSAvoidmaterial costs
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The invention removes the release paper component entirely, eliminating the associated material costs while maintaining blocking prevention through the engineered adhesive composition's temperature-dependent properties

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The adhesive composition provides self-service blocking prevention through its inherent temperature-dependent tackiness, eliminating the need for separate release paper components and their associated costs

Inventive Principle:
Principle #25Self-service

3Reliability

If polymers with Tg>+50°C are used, then blocking prevention is improved, but activation temperature increases

Engineering Contradiction:
Improveblocking preventionVSAvoidactivation temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The invention creates a composite adhesive system combining polymers with Tg>+50°C (for blocking prevention) and Tg<+10°C (for lower temperature activation), achieving both blocking prevention and reduced activation temperature requirements

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the activation temperature parameter by introducing low-Tg polymers that become tacky at lower temperatures, allowing the high-Tg polymer system to be activated without requiring excessively high temperatures

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If pressure sensitive adhesive is used, then ease of application is improved, but blocking occurs during rolling

Engineering Contradiction:
Improveapplication easeVSAvoidblocking during rolling
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention changes the temperature parameter of the adhesive system, creating pressure-sensitive adhesive that remains non-tacky at room temperature (preventing blocking) but becomes activatable at elevated temperatures (maintaining application ease when needed)

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces dynamic temperature-dependent properties to the adhesive, allowing it to switch between non-tacky (during rolling) and tacky (during application) states based on temperature conditions

Inventive Principle:
Principle #15Dynamics

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 adhesive composition effectively prevents label blocking at high temperatures and tensions without release papers, enabling the use of 'linerless labels' with improved adhesive properties and reduced material costs, while being activatable at temperatures below 90°C.

Implementation Method 1

at least one acrylate polymer with a glass transition temperature Tg in the range from +50° C. to +90° C. and at least one amorphous polyurethane or polyurethane-polyurea polymer with a glass transition temperature Tg in the range from −50° C. to +10° C.

Methodology Applied
Scientific EffectGlass transition temperature:

Implementation Method 2

can at the same time be activated at temperatures above 50° C.

Methodology Applied
Scientific EffectThermal activation: Heating

Implementation Method 3

does not lead to a blocking of the label layers even at high winding tensions and at temperatures up to 50° C.

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentUS8980407B2Linerless label
Publication Date: 2015.03.17 COVESTRO DEUTSCHLAND AG

AI summary

The invention relates to an aqueous adhesive composition containing at least one acrylate polymer with a glass transition temperature Tg&gt;50° C. and at least one amorphous polyurethane or polyurethane-polyurea polymer with a glass transition temperature Tg&lt;+10° C., the use of the adhesive compositions for the manufacture of heat-activated adhesive layers, and planar formations containing adhesive layers based on the adhesive composition.