Stratified Yankee Dryer Paper Sheet Lint Reduction
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Solution Overview
Problem
Consumer preferences for paper towels are negatively impacted by high levels of lint generated during use, which existing papermaking strategies fail to adequately address while maintaining desired attributes like dry strength, wet strength, softness, and absorbency.
Innovation Solution
The development of paper products with stratified base sheets, where the outer layers are composed of at least 80% softwood fibers with specific fiber length and coarseness, and the use of Yankee dryers with strategic layering and processing techniques to reduce lint production, including the application of wet strength resins and fiber refinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional papermaking strategies are used to maintain desired attributes (dry strength, wet strength, softness, absorbency), then product performance is preserved, but lint generation remains high
Solution Approach 1:
The patent applies local quality by creating a stratified base sheet where the outer layer has different fiber composition (at least 80% softwood fibers with specific length and coarseness) compared to the inner layer. This localized differentiation allows the outer layer to specifically address lint reduction while the inner layer maintains overall structural integrity and product performance attributes.
Solution Approach 2:
The patent changes critical fiber parameters including fiber length (between 0.2-3.0 mm), coarseness (≤16 mg/100m), and fiber composition (≥80% softwood) in the outer layer. These parameter modifications are specifically targeted to reduce lint generation while maintaining the required mechanical and functional properties of the paper product.
2Object-generated harmful factors
If fiber length and coarseness are reduced to minimize lint, then lint generation decreases, but dry strength and wet strength may be compromised
Solution Approach 1:
The patent segments the base sheet into at least two distinct layers with different fiber characteristics. The outer layer uses shorter, finer softwood fibers optimized for lint reduction, while the inner layer can incorporate longer or different fiber types optimized for strength. This segmentation allows each layer to be optimized for its specific function without compromising the other.
Solution Approach 2:
The patent creates a composite structure by combining different fiber types and properties in specific layers. The outer layer comprises at least 80% softwood fibers with specific length and coarseness for lint reduction, while the inner layer may contain different fiber compositions for strength, creating a multi-component material system that simultaneously achieves both lint reduction and strength requirements.
3Object-generated harmful factors
If softwood fibers with specific properties are used in the outer layer to reduce lint, then lint generation is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating a stratified base sheet where the outer layer has different fiber composition (at least 80% softwood fibers with specific length and coarseness) compared to the inner layer. This localized differentiation allows the outer layer to specifically address lint reduction while the inner layer maintains overall structural integrity and product performance attributes.
Solution Approach 2:
The patent incorporates wet strength resins and applies fiber refinement treatments during the manufacturing process to pre-condition the fibers and enhance bond strength before the product reaches the consumer. This preliminary action ensures that the specialized outer layer maintains its lint-reducing properties while achieving the necessary structural integrity.
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
Significantly reduces lint generation during use while maintaining consumer-desired properties, with the Yankee layer being strengthened to enhance cohesion and reduce fiber escape, resulting in lower lint levels and improved product performance.
Implementation Method 1
drying the dewatered web with the Yankee dryer to form a fibrous sheet
Implementation Method 2
The outer layers are composed of at least 80% softwood fibers with specific fiber length and coarseness, and the use of Yankee dryers with strategic layering and processing techniques to reduce lint production, including the application of wet strength resins
Data Source
AI summary
A method of making a fibrous sheet includes providing a first furnish including a primary pulp having papermaking fibers, the papermaking fibers (i) having a weight-weighted average fiber length between about two and seven tenths millimeters and about three millimeters, (ii) a coarseness of about sixteen milligrams per one hundred meters or lower, and (iii) being at least eighty percent of the papermaking fibers of the first furnish, forming a nascent web having at least two layers, one of the at least two layers being (i) a surface layer of the nascent web and (ii) formed from the first furnish, dewatering the nascent web to form a dewatered web, applying the surface layer of the dewatered web to the outer surface of a Yankee drum of a Yankee dryer, and drying the dewatered web with the Yankee dryer to form a fibrous sheet.