Coreless Absorbent Roll Polymer Coating for Collapse Resistance

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Solution Overview

Problem

Coreless rolls of absorbent sheet products face issues with collapsing, lack of flexibility, and difficulty in reopening the axial hollow passageway after compression, leading to increased storage costs and potential sewage clogging.

Innovation Solution

A coreless roll design featuring a continuous web of absorbent material with a specific polymer and binding agent coating composition, applied to the second end, which provides excellent resistance to collapsing and flexibility, allowing the roll to maintain a well-defined axial hollow passageway when uncompressed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a coreless roll design is used to eliminate the rigid core, then storage space is reduced and sewage clogging is prevented, but the roll becomes prone to collapsing and loses structural stability

Engineering Contradiction:
Improvestorage spaceVSAvoidstructural stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies a flexible polymer coating layer on the inner surface of the absorbent sheet, which acts as a thin film structure to maintain the roll's structural integrity without requiring a rigid core. This flexible coating provides the necessary mechanical support to prevent collapsing while allowing the roll to be stored in compressed form.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure by combining the absorbent sheet material with a polymer coating layer. This composite material approach integrates the functional properties of both materials: the absorbency of the sheet and the structural support of the polymer coating, achieving both space efficiency and stability.

Inventive Principle:
Principle #40Composite materials

2Volume of moving object

If the roll is compressed to reduce storage space, then storage and transport costs are reduced, but the axial hollow passageway becomes difficult to reopen and maintain

Engineering Contradiction:
Improvestorage spaceVSAvoidease of reopening passageway
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The flexible polymer coating layer on the inner surface provides elastic memory that enables the roll to return to its cylindrical shape after compression. This thin film structure maintains the structural definition of the axial hollow passageway while allowing reversible deformation during compression and decompression cycles.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces dynamic flexibility to the roll structure through the polymer coating, allowing it to adapt between compressed and uncompressed states. The coating enables the roll to dynamically transition between storage mode (compressed) and usage mode (uncompressed with open passageway) while maintaining structural integrity in both states.

Inventive Principle:
Principle #15Dynamics

3Strength

If a polymer coating is applied to the inner surface, then resistance to collapsing and flexibility are improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveresistance to collapsingVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the coating application process with the existing manufacturing workflow by applying the polymer coating during the web formation or rolling process. This integration combines multiple functions (coating application, drying, and structural reinforcement) into a single continuous manufacturing step, reducing overall process complexity despite adding the coating function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent optimizes the polymer coating parameters (thickness, composition, application method) to achieve the desired mechanical properties while minimizing processing complexity. By carefully controlling the coating parameters, the patent achieves effective collapse resistance with a simple, scalable manufacturing process suitable for industrial production.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the continuous web is wound without a core to eliminate manual handling, then manufacturing efficiency is improved, but the roll becomes difficult to mount on the spindle

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidease of mounting on spindle
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The flexible polymer coating maintains the structural definition of the axial hollow passageway, creating a well-defined opening that facilitates easy mounting on the spindle. The thin film structure provides just enough rigidity to maintain the passageway shape while allowing the roll to be handled and mounted without a rigid core.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent prepares the roll structure in advance during manufacturing by forming the axial hollow passageway with the polymer coating reinforcement. This preliminary structuring ensures that when the roll reaches the consumer, it is ready for immediate mounting on the spindle without requiring additional preparation or a rigid core for structural support.

Inventive Principle:
Principle #10Preliminary action

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 solution enhances the coreless roll's resistance to collapsing, flexibility, and disintegrability in water, enabling full-length use without clogging sewage systems and maintaining product quality.

Implementation Method 1

the absorbent sheet product constituting the first inner turns of the roll must be stably maintained when the roll is returned from the compressed form to the uncompressed form... the roll must hence exhibit substantial flexibility and a certain level of elasticity

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the second end of the continuous web of absorbent material comprises a coating composition comprising a specific polymer and a binding agent

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3688225B1Coreless roll of absorbent sheet and method for manufacturing the same
Publication Date: 2022.11.30 ESSITY HYGIENE & HEALTH AB
  • EP3688225B1 patent drawingFigure 1~2
  • EP3688225B1 patent drawingFigure 3
  • EP3688225B1 patent drawingFigure 4a~4b

AI summary

The present invention relates to a coreless roll of an absorbent sheet product such as napkins, toilet paper, towels etc. made of a spirally wound continuous web of absorbent material having a first end and a second end, wherein a coating composition comprising a specific polymer and a binding agent in a weight ratio polymer to binding agent of at least 92:8 is coated onto the second end. The coreless roll of the present invention has excellent resistance to collapsing, as well as excellent flexibility and elasticity. Moreover, the coreless roll of the present invention has excellent disintegrability in water and can be used up over its whole length. The present invention also relates to a process for the manufacture of the coreless roll.