Soft Textured Tissue via Through-Air Drying Fabric Protuberances
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Solution Overview
Problem
Tissue products face a challenge in balancing softness, surface texture, and bulk, as increasing one property often negatively affects the others, making it difficult to achieve high softness levels with moderate surface texture and bulk without compromising on density.
Innovation Solution
Through-air drying fabrics with discrete protuberances are used to create tissue webs with a three-dimensional surface topography, allowing for improved surface texture and bulk while maintaining softness, by controlling the height and angle of the protuberances to achieve specific TS7 and R2 values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If coarse through-air drying fabrics with high surface topography are used to generate bulk, then sheet bulk is improved, but surface smoothness deteriorates and softness decreases
Solution Approach 1:
The through-air drying fabric is designed with localized three-dimensional protuberances rather than uniform coarse topography. These discrete protuberances create bulk and texture only where needed, while maintaining smoothness in the valleys between protuberances, thus achieving both bulk and softness simultaneously
Solution Approach 2:
The invention transitions from two-dimensional surface texture to three-dimensional protuberances with specific height (0.5-1.5mm) and angular characteristics. This third dimension allows the fabric to impart bulk and texture while the controlled geometry ensures the surface remains soft to the touch, resolving the contradiction between bulk and softness
2Object-affected harmful factors
If surface topography is reduced to produce smoother web, then surface smoothness is improved, but web density increases and softness deteriorates
Solution Approach 1:
The invention optimizes specific parameters of the through-air drying fabric: protuberance height (0.5-1.5mm), protuberance spacing, and fabric porosity. By controlling these parameters, the fabric creates surface texture without excessive density, maintaining softness while providing bulk and texture
3Quantity of substance
If fiber-fiber bonding is increased to reduce density, then web density is improved, but softness deteriorates
Solution Approach 1:
The through-air drying process is used as a preliminary non-compressive drying method that sets the web structure before final bonding occurs. This preliminary action creates a loose, bulkier structure with controlled bonding, preventing excessive density while maintaining softness by avoiding aggressive compression bonding
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 method enables tissue products with TS7 values less than 11.0 and R2 values greater than 11,000, achieving high softness and bulk without increasing density, resulting in improved tissue products with enhanced wiping utility and aesthetic appeal.
Implementation Method 1
The wet-laid web is molded to the through-air drying fabric and is supported by the fabric until it is at least almost completely dry
Implementation Method 2
The wet molded web is typically dried by passing heated air through both the fabric and the wet web as it is transported over a cylindrical dryer
Data Source
AI summary
Provided are tissue webs and products that have a modest degree of surface texture, but are still soft. In certain instances the tissue products and webs may also have good sheet bulk and low stiffness. For example, the tissue products may have good softness, such as a TS7 value (measured using the EMTEC Tissue Softness Analyzer) less than 11.0, and a textured surface, such as an R2 value from about 11,000 to about 20,000 (measured using an OpTiSurf tester). The foregoing tissue products may have a sheet bulk greater than about 8.0 cc/g and a Stiffness Index less than about 15.0. In certain instances the tissue product and webs may be through-air dried and may be either creped or uncreped.