A coreless roll and a manufacturing method
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Solution Overview
Problem
Coreless rolls of absorbent sheet products are prone to collapsing during manufacturing, packaging, shipping, and use, especially at high industrial speeds, due to lack of sufficient stiffness, and existing solutions are complex and costly to implement.
Innovation Solution
A coreless roll design featuring a spirally wound web with a stiffening insert positioned within the axial hollow passageway, extending at least three-quarters of the circumference, made from materials like tissue paper, nonwoven, or cardboard, providing resistance to compression comparable to a cardboard core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a water based liquid is sprayed onto the web material to create a rigid core, then the coreless roll becomes more resistant to collapsing, but the manufacturing process becomes technically complex and costly
Solution Approach 1:
The patent uses a disposable stiffening insert made of inexpensive material (tissue paper, nonwoven, or cardboard) that is inserted into the coreless roll to provide structural support. This insert is discarded after use, replacing the complex water-spraying process with a simple mechanical insertion of a cheap support element that eliminates the need for complex manufacturing equipment.
2Stress or pressure
If a stiffening insert is inserted in-between two superposed plies to line the axial hollow passageway, then the resistance to compression is improved, but the device complexity increases
Solution Approach 1:
The stiffening insert is positioned specifically within the axial hollow passageway of the coreless roll, providing localized structural support exactly where needed. The insert lines the passageway and extends around at least three-quarters of the circumference, concentrating the stiffening function in the critical central region without adding complexity to the entire roll structure.
3Strength
If the stiffening insert extends completely around the passageway, then the resistance to collapsing is maximized, but the manufacturing complexity and cost increase
Solution Approach 1:
The stiffening insert extends around at least three-quarters of the circumference of the axial hollow passageway, providing sufficient structural support without requiring complete 360-degree coverage. This partial action achieves the necessary resistance to collapsing while simplifying the manufacturing process and reducing material requirements compared to a fully circumferential insert.
Data Source
Figure 1
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AI summary
A coreless roll of absorbent sheet products is made of a spirally wound web (11) of absorbent substrate comprising at least two superposed plies (10A, 10B) of absorbent substrate, the web of absorbent substrate being wound such as to define an axial hollow passageway (42) centrally positioned relatively to the coreless roll (40) and extending from one edge to another edge of the coreless roll (40). The web of absorbent substrate (11) further comprises a stiffening insert (16), the stiffening insert (16) being inserted in-between two superposed plies (10A, 10B) of absorbent substrate, the stiffening insert (16) being positioned such as to line the axial hollow passageway (42), the stiffening insert (16) having a length (L) such that the stiffening insert (16) extends at least around three quarter of a circumference of the passageway (42), preferably substantially completely around a circumference of the passageway (42).