Multilayer Adhesive Composition for Liner-Free Labels
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Solution Overview
Problem
Conventional liner-free label technologies face challenges with adhesion to various substrates, particularly smooth low surface energy substrates, and are prone to 'swimming' due to slow bond formation, while also generating waste and causing machine issues in labeling processes.
Innovation Solution
A multilayer adhesive composition with a hydrophilic adhesive layer and a barrier layer, where the hydrophilic and hydrophobic polymers provide quick tack and strong adhesion, respectively, and hygroscopic particulate fillers enhance rapid activation and anti-blocking properties, preventing interaction between adjacent labels during storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymeric adhesive compositions with pressure-sensitive adhesives are used in liner-free label constructions, then the adhesive provides constant tackiness, but it causes machine problems by gumming up label application systems and creates cleanup issues
Solution Approach 1:
The patent transforms the adhesive from a permanently tacky state to a latent state that activates only when needed. The adhesive composition undergoes parameter changes in response to environmental conditions (moisture, temperature) or chemical activators, transitioning from non-tacky during storage to tacky during application, eliminating constant gumming problems while maintaining reliability when required
Solution Approach 2:
The adhesive is prepared in advance in a non-tacky latent state that prevents machine gumming during storage and handling. The tacky properties are activated preliminarily only at the moment of application through exposure to moisture, heat, or chemical activators, ensuring reliability without continuous harmful effects
2Adaptability or versatility
If carbohydrate and synthetic polymeric adhesives are used in dry-gum or water/solvent activated labels, then the adhesive can be activated, but it has little utility on synthetic and non-porous substrates as it does not form substantial adhesive or mechanical bonds
Solution Approach 1:
The patent employs composite adhesive formulations combining multiple polymer types with complementary properties. The composition includes both carbohydrate-based and synthetic polymeric components, creating a hybrid adhesive system that leverages the benefits of each material type to achieve broad substrate compatibility and strong bonding across diverse surfaces
Solution Approach 2:
The adhesive composition contains different polymer components with specialized functions distributed throughout the formulation. Hydrophilic polymers provide quick tack for porous substrates while hydrophobic polymers provide strong adhesion for non-porous substrates, with each component acting locally to address specific substrate types
3Reliability
If labels are stored in coils or foldable stacks under high temperature and humidity conditions, then the adhesive layer can provide strong adhesion, but it interacts with the face of adjacent labels causing sticking and damage
Solution Approach 1:
The patent introduces a barrier layer as an intermediary between the adhesive layer and the label face. This intermediate layer prevents direct contact and interaction between adjacent labels during storage while allowing the adhesive to maintain its strong bonding capabilities when activated for application
Solution Approach 2:
The label structure is segmented into distinct functional layers: an adhesive layer for bonding and a separate barrier layer for protection. This segmentation allows each layer to perform its specific function independently - the adhesive provides strength when needed while the barrier prevents harmful interactions during storage
4Adaptability or versatility
If activatable adhesive labels are made with fluid-activatable compositions, then the adhesive can be activated prior to or after printing, but it requires special liner-free label printers and application systems
Solution Approach 1:
The adhesive composition is designed to activate automatically through self-service mechanisms using readily available environmental conditions. The adhesive responds to ambient moisture, temperature changes, or simple chemical exposure that occur naturally during standard labeling operations, eliminating the need for specialized activation equipment while maintaining timing flexibility
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 enables quick and strong adhesion to a variety of substrates, reduces 'swimming' issues, and prevents label interaction during storage, improving labeling efficiency and reducing waste.
Implementation Method 1
The adhesive composition contains a hydrophilic polymer and a hydrophobic polymer, wherein the hydrophilic polymer provides quick tack when exposed to water or other aqueous solvent
Implementation Method 2
the less hydrophilic polymer has a characteristic which enables strong adhesion to a paper or polymeric substrate
Implementation Method 3
There exists a need for a barrier composition which can prevent interaction between the adhesive layer on one label and the label face of an adjacent label without compromising the adhesive strength of the adhesive layer
Data Source
AI summary
Fluid activatable, multilayer adhesive compositions for use with liner-free labels, and methods of making and using thereof are described herein. The compositions contain a functional layer, such as an adhesive layer, which is applied to the label and a barrier layer which is applied on top of the adhesive layer. The multilayer composition prevents the adhesive layer on the label from interacting with the face of an adjacent label, particularly when the labels are stored as coils or folded stacks.