Fibrillated Regenerated Cellulose Microfiber Network for Absorbent Sheets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional absorbent sheets made from lyocell fibers face challenges such as fibrillation, flocculation, and difficulty in integration with papermaking processes, limiting their use in absorbent webs, and existing methods struggle to achieve optimal combinations of wet strength, absorbency, and softness.
Innovation Solution
Incorporating fibrillated regenerated cellulose microfibers into a papermaking fiber matrix, with controlled fibrillation to reduce coarseness and freeness, forming a microfiber network that enhances absorbency, strength, and softness, and using a debonder pre-treatment to further improve sheet properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional lyocell fibers are used in absorbent sheets, then fiber strength is maintained, but fibrillation occurs and flocculation happens making integration with papermaking processes difficult
Solution Approach 1:
The patent divides conventional lyocell fibers into microfibers through intensive refining, reducing fiber diameter to 0.5-5 micrometers. This segmentation eliminates fibrillation and flocculation issues while maintaining strength, as the microfibers integrate smoothly into papermaking processes without forming clumps.
Solution Approach 2:
The patent changes the physical parameters of lyocell fibers by controlling refinement intensity to achieve specific microfiber dimensions (0.5-5 micrometers diameter, 0.1-10 mm length). This parameter transformation allows the fibers to behave differently in papermaking processes, preventing the harmful fibrillation and flocculation while preserving mechanical strength.
2Quantity of substance
If regenerated cellulose microfiber is added to enhance absorbency and softness, then SAT value and softness improve, but wet strength may be compromised
Solution Approach 1:
The patent creates a composite structure by incorporating 1-30% regenerated cellulose microfibers into a papermaking fiber matrix. The microfibers form a three-dimensional network that simultaneously enhances absorbency (SAT value) and wet tensile strength, resolving the trade-off between softness and strength retention.
Solution Approach 2:
The patent applies local quality enhancement by distributing microfibers throughout the paper matrix at controlled concentrations (1-30% by weight). This localized reinforcement provides enhanced absorbency and wet strength where needed while maintaining the overall balance of the paper structure, preventing over-softening.
3Quantity of substance
If microfiber network is formed to improve absorbency and strength, then SAT value and wet tensile increase, but GM Break Modulus decreases indicating reduced stiffness
Solution Approach 1:
The patent changes the structural parameters of the paper by incorporating microfibers with specific dimensions (0.5-5 micrometers diameter). This parameter change creates a network structure that enhances absorbency and strength while naturally reducing stiffness (GM Break Modulus), achieving the desired balance of properties.
Solution Approach 2:
The patent creates a composite material system where regenerated cellulose microfibers form a network within the papermaking fiber matrix. This composite structure provides enhanced absorbency and wet tensile strength while the microfiber network architecture inherently reduces stiffness, achieving the target property profile.
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 resulting absorbent sheets exhibit elevated SAT values, wet tensile values, improved wet/dry tensile ratios, lower GM Break Modulus, and increased bulk, enabling the production of softer products with enhanced strength and absorbency.
Implementation Method 1
Fibrillation of the regenerated cellulose microfiber is controlled such that it has a reduced coarseness and a reduced freeness as compared with unfibrillated regenerated cellulose fiber from which it is made
Implementation Method 2
the lyocell microfiber is sized and distributed in the fiber matrix to form a microfiber network therein... the absorbent sheet exhibits an elevated SAT value and an elevated wet tensile value
Data Source
AI summary
An absorbent paper sheet for tissue or towel includes from about 99 percent to about 70 percent by weight of cellulosic papermaking fiber and from about 1 percent to about 30 percent by weight fibrillated regenerated cellulose microfiber which was regenerated form a cellulosic dope utilizing a tertiary amine N-oxide solvent or an ionic liquid. Fibrillation of the microfiber is controlled such that it has a reduced coarseness and a reduced freeness as compared with unfibrillated regenerated cellulose microfiber from which it is made and provides at least one of the following attributes to the absorbent sheet: (a) the absorbent sheet exhibits an elevated SAT value and an elevated wet tensile value as compared with a like sheet prepared without fibrillated regenerated cellulose microfiber; (b) the absorbent sheet exhibits an elevated wet/dry CD tensile ratio as compared with a like sheet prepared without fibrillated regenerated cellulose microfiber; (c) the absorbent sheet exhibits a lower GM Break Modulus than a like sheet having like tensile values prepared without fibrillated regenerated cellulose microfiber; or (d) the absorbent sheet exhibits an elevated bulk as compared with a like sheet having like tensile values prepared without fibrillated regenerated cellulose microfiber. In some embodiments, the pulp is pre-treated with debonder to enhance the wet/dry CD tensile ratio of the sheet.