Tackifier-Free Polyolefin Adhesive for Absorbent Articles
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Solution Overview
Problem
Existing hot-melt adhesives used in disposable absorbent articles, such as diapers, are costly and have performance limitations due to the high expense and difficulty in sourcing tackifiers, which can also compromise the integrity of the polyethylene backsheet and impart undesirable odors.
Innovation Solution
A construction adhesive comprising an amorphous polyolefin composition with greater than 40% 1-butene and a second amorphous polymer with a molecular weight of at least 1000, compatible with the polyolefin, is used, eliminating the need for tackifiers to improve performance and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tackifiers are used in hot-melt adhesive formulations, then adhesive performance can be improved, but the cost increases significantly and sourcing becomes difficult
Solution Approach 1:
The patent removes tackifiers from the adhesive formulation entirely, extracting the problematic component that causes high cost and sourcing difficulties. The adhesive achieves acceptable performance without this expensive additive by relying on the polyolefin composition itself.
Solution Approach 2:
The patent changes the chemical composition parameters of the adhesive by specifying a polyolefin composition with more than 40% 1-butene content and controlling the molecular weight of the polyethylene backsheet to at least 100,000. These parameter changes allow the adhesive to function effectively without tackifiers.
2Reliability
If tackifiers are used in adhesive formulations, then bonding performance can be enhanced, but the polyethylene backsheet integrity may be compromised
Solution Approach 1:
The patent extracts removes tackifiers from the adhesive system, eliminating the harmful interaction between tackifiers and the polyethylene backsheet that compromises integrity. The adhesive achieves sufficient bonding performance through the polyolefin composition alone.
Solution Approach 2:
The patent converts the potential harm of tackifier-backsheet interaction into a benefit by eliminating tackifiers entirely and using the polyolefin composition's inherent properties to achieve bonding without damaging the backsheet integrity.
3Reliability
If tackifiers are used in adhesive formulations, then adhesive properties can be improved, but undesirable odors are imparted to the absorbent article
Solution Approach 1:
The patent extracts removes tackifiers from the adhesive formulation, eliminating the source of undesirable odors. The adhesive maintains necessary bonding properties through the polyolefin composition without the odorous tackifier components.
4Ease of manufacture
If conventional hot-melt adhesives are used, then manufacturing process is simple, but cohesive strength and peel strength are insufficient
Solution Approach 1:
The patent changes the chemical parameters of the adhesive by using a polyolefin composition with more than 40% 1-butene content and controlling molecular weights, which improves cohesive strength and peel strength while maintaining manufacturing simplicity.
Solution Approach 2:
The patent uses a composite adhesive system consisting of polyolefin composition combined with a compatibilizer, creating a material with enhanced mechanical properties including cohesive strength and peel strength while remaining manufacturable.
Data Source
AI summary
Disposable absorbent articles assembled from a collection of components using an adhesive composition is disclosed. The adhesive composition comprises at least 90 wt. % of a copolymer, wherein the copolymer comprises from about 30 mole % to about 70 mole % of propene monomer units and from about 30 mole % to about 75 mole % of 1-butene monomer units. The adhesive composition is free of a heterophase copolymer.