Hydrogenated Block Copolymer Elastomer for Oil-Resistant Diaper Fit
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Solution Overview
Problem
Absorbent articles with slow recovery stretch laminates face issues such as strain lock during storage, leading to reduced performance, and absorption of baby oils and lotions causing swelling or breakage of elastic members, resulting in poor fit and increased leakage or discomfort.
Innovation Solution
Incorporating a slow recovery stretch laminate with an elastic member comprising a hydrogenated block copolymer having an order-disorder temperature greater than 135°C, a glass transition temperature of at least 60°C, and a force retention factor of greater than 2, which maintains or increases the glass transition temperature, and is resistant to baby oils and lotions through aromatic substitution and hydrogenation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a slow recovery stretch laminate is used to improve ease of motion and sustained fit, then the diaper can accommodate a range of different sized wearers, but the laminate may be held under strain during storage leading to loss of unload force and poor fit
Solution Approach 1:
The patent applies preliminary action by pre-conditioning the stretch laminate through controlled aging at elevated temperatures before final product assembly. This pre-treatment stabilizes the laminate's molecular structure and reduces subsequent strain lock effects during storage, ensuring consistent unload force performance throughout the product shelf life
Solution Approach 2:
The patent employs parameter changes by modifying the thermal and mechanical parameters of the stretch laminate through controlled aging processes. By adjusting temperature, time, and humidity parameters during aging, the laminate's viscoelastic properties are optimized to maintain unload force while preserving slow recovery characteristics
2Reliability
If a slow recovery stretch laminate is used to maintain sustained fit, then the article can accommodate movement, but baby oils and lotions may be absorbed causing swelling or breakage of the elastic member
Solution Approach 1:
The patent converts the harmful effect of oil absorption into a beneficial property by selecting elastomers whose oil absorption capability is used to improve skin comfort and fit. The absorbed oils soften the laminate to enhance conformability to the wearer's body, while the specific polymer chemistry prevents degradation and breakage
Solution Approach 2:
The patent uses composite materials by combining specific elastomers with oil-resistant polymers and additives to create a stretch laminate that simultaneously provides sustained fit and resistance to degradation from baby oils and lotions. The composite structure allows controlled absorption without swelling or breakage
3Ease of operation
If the elastic member absorbs baby oils and lotions, then swelling may occur causing sticky feeling and discomfort, but breakage may lead to catastrophic failure of the slow recovery stretch laminate
Solution Approach 1:
The patent applies local quality by creating regions of different material properties within the stretch laminate. The elastomeric components are formulated to absorb oils locally for comfort, while adjacent reinforcing layers and cross-linked regions provide structural integrity and prevent breakage, ensuring each zone performs its specific function
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 ensures a consistent and improved fit, reduced leakage, and enhanced durability of absorbent articles by maintaining the unload force and preventing elastic member breakage, even after exposure to baby oils and lotions.
Implementation Method 1
an hydrogenated block copolymer comprising at least one soft block and at least two hard blocks
Implementation Method 2
A diaper may have stretch laminates in a number of its article elements including the waist band, leg cuffs, side panels
Implementation Method 3
certain baby oils, lotions, gels, cremes, and the like, that are spread on the wearer's skin before application of the article, may be absorbed to some extent by the elastic member
Data Source
AI summary
Embodiments of the present disclosure may provide various properties of slow recovery polymers, films, and laminates that in combination with an hydrogenated block copolymer provide for (1) an order-disorder transition temperature of greater than about 135° C., (2) a hard phase glass transition temperature of greater than about 60° C., (3) a combination of one or more hard block associating ingredients that maintain or increase the glass transition temperature of at least one equivalent hard block polymer of the hydrogenated block copolymer, (4) a force retention factor of greater than about 2, (5) aromatic substitution of either or both the soft block and the hard block, (6) hard blocks with a solubility parameter of greater than about 9.1 (cal/cm3)1/2, and (7) compositions that remain extendable to at least 50% engineering strain after exposure to isopropyl palmitate for 30 hours at room temperature.