Spirally Wound Tissue Web Design for Single-Handed Dispensing
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Solution Overview
Problem
Spirally wound fibrous webs, such as bath tissue, are inconvenient to dispense as they require two hands to unwind and may tear irregularly due to inconsistent perforation functionality.
Innovation Solution
Balancing the cross-machine direction (CD) tensile strength and detach strength of the tissue web to achieve a ratio of 0.65 or less, allowing for single-handed dispensing by adjusting the manufacturing process to include specific tensile strength ranges and perforation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tissue web is provided with spaced-apart lines of perforations to facilitate dispensing, then the web can be divided into useable sheets, but the web may tear irregularly and the perforations do not always function as desired
Solution Approach 1:
The patent applies parameter changes by optimizing the detach strength to CD tensile strength ratio to 0.65 or less, and controlling the percent bonded area of perforations within specific ranges. These parameter adjustments ensure that the perforations function reliably to separate sheets while maintaining consistent tearing behavior, resolving the contradiction between dispensing ease and perforation reliability.
2Ease of operation
If the user unwinds the desired number of sheets and tears the web along the chosen line of perforations, then the web can be dispensed, but it takes two hands to dispense the web
Solution Approach 1:
The patent applies self-service by designing the tissue web with optimized detach strength characteristics that enable automatic sheet separation during dispensing. The controlled ratio of detach strength to CD tensile strength (0.65 or less) allows the web to separate along perforations automatically when pulled, eliminating the need for a second hand to hold the roll, thus enabling single-handed dispensing.
3Strength
If the CD tensile strength is increased to prevent tearing, then the web strength is improved, but the detach strength ratio increases making single-handed dispensing difficult
Solution Approach 1:
The patent resolves this contradiction through precise parameter changes by controlling the detach strength to CD tensile strength ratio to be 0.65 or less. This optimized ratio ensures that the web maintains sufficient strength to prevent unwanted tearing while simultaneously enabling easy single-handed dispensing, as the perforated sections separate cleanly at the appropriate force threshold.
Data Source
AI summary
The present invention provides rolled products, such as spirally wound rolls of bath tissue comprising a plurality of separably joined sheets, that may be repeatably and reliably dispensed by a user with a single hand. Single handed dispensing of the rolled products is facilitated by the web having a ratio of detach strength, typically having units of grams (g) to cross-machine direction (CD) tensile, having units of grams per 76.2 mm, of 0.65 or less, such as from about 0.10 to 0.65. In this manner rolled bath tissue products may have a CD tensile from about 400 to about 1,000 g/76.2 mm and a detach strength from about 100 to about 500 g.