Hot Melt Adhesive Composition for Wet Nonwoven Bonding
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Solution Overview
Problem
Hot melt adhesives used in nonwoven absorbent articles face challenges with low adhesion in wet conditions, particularly in hydrophilic materials, and the addition of acid-modified waxes to enhance adhesion leads to undesirable odor and color changes.
Innovation Solution
A hot melt adhesive composition comprising metallocene-catalyzed propylene-based copolymers, polyolefin copolymers, and tackifiers, without acid-modified components, to provide enhanced wet adhesion and maintain adhesion strength in nonwoven materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acid-modified waxes are added to increase wet adhesion, then wet adhesion is improved, but odor and color quality deteriorate
Solution Approach 1:
The invention extracts and eliminates acid-modified waxes from the adhesive composition while maintaining wet adhesion performance through alternative components, thereby removing the source of odor and color problems
Solution Approach 2:
The invention changes the chemical composition parameters by using specific metallocene-catalyzed copolymers with controlled ethylene content (1-20 wt%) and acid-grafted polyolefin copolymers with controlled acid content (0.1-5 wt%), achieving wet adhesion without acid-modified waxes
2Productivity
If conventional hot melt adhesives are used for rapid bonding, then bonding speed is improved, but adhesion in wet state deteriorates
Solution Approach 1:
The invention creates a composite adhesive system combining metallocene-catalyzed propylene-based copolymers with acid-grafted polyolefin copolymers and tackifiers, achieving both rapid bonding and wet adhesion through synergistic component interaction
Solution Approach 2:
The invention modifies the adhesive composition by incorporating acid-grafted polyolefin copolymers with specific acid content (0.1-5 wt%) and metallocene-catalyzed copolymers with controlled ethylene content (1-20 wt%), enabling both fast bonding and wet state adhesion
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 composition achieves high wet bonding strength in nonwoven materials, avoiding the odor and color issues associated with acid-modified waxes, ensuring effective adhesion even in moist environments.
Implementation Method 1
Hot melt adhesives are substances which are solid at room temperature and which often comprise neither water nor solvent. They are applied in the molten state after heating to a temperature generally of between 10° and 250° C., most often between 13° and 180° C., and solidify during cooling, thus forming a seal (or adhesive joint) which ensures the attachment of the two substrates to be assembled.
Implementation Method 2
They are applied in the molten state after heating to a temperature generally of between 10° and 250° C., most often between 13° and 180° C., and solidify during cooling, thus forming a seal (or adhesive joint) which ensures the attachment of the two substrates to be assembled. Hot melt adhesives are generally provided in the form of compositions which comprise a thermoplastic polymer and optionally a tackifying resin and a plasticizer.
Data Source
AI summary
The invention concerns a hot melt adhesive composition comprising: i) a first metallocene-catalyzed propylene-based copolymer; ii) a second metallocene-catalyzed propylene-based copolymer; iii) a polyolefin copolymer selected from the group consisting of: iii-1) acid-grafted polyolefin copolymer; iii-2) a copolymer based on olefins and unsaturated monomers containing acid groups or anhydride groups; and iii-3) mixtures thereof; iv) a tackifier; v) optionally a third metallocene-catalyzed propylene-based copolymer, wherein each of the metallocene-catalyzed propylene-based copolymers i) and ii) comprises, independently of each other, from 1% to 20% by weight of ethylene units.