Multilayer Creping Belt for Absorbent Sheet Caliper and Softness
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Solution Overview
Problem
Existing creping belts and fabrics in papermaking processes face limitations in achieving higher caliper and softness simultaneously due to constraints on opening size and shape, fiber retention, and material durability, leading to suboptimal paper product properties.
Innovation Solution
A multilayer creping belt with a polymeric top layer for forming diverse openings and a woven or extruded polymeric bottom layer for strength and fiber retention, preventing fiber passage while allowing air flow, enabling the creation of paper products with enhanced caliper and softness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If woven structuring fabrics are used for creping, then strength and dimensional stability are improved, but the variety and size of openings are limited
Solution Approach 1:
The belt is divided into multiple independent layers: a woven fabric layer providing strength and dimensional stability, and a thermoplastic layer providing diverse opening configurations. This segmentation allows each layer to fulfill its specific function without compromise.
Solution Approach 2:
The invention uses a composite structure combining woven fabric material with thermoplastic material. The woven layer contributes tensile strength while the thermoplastic layer contributes opening variety and web interaction properties, achieving synergistic performance.
2Manufacturing precision
If larger openings are created in creping belts, then caliper and softness are improved, but fiber retention deteriorates
Solution Approach 1:
The solution moves from a two-dimensional woven structure to a three-dimensional multilayer structure. The thermoplastic layer with its diverse opening patterns sits atop the woven layer, creating vertical depth that allows large openings for caliper while the underlying woven layer provides fiber retention barrier.
Solution Approach 2:
Different regions of the belt have different properties: the thermoplastic layer has large openings in specific patterns for caliper control, while the woven fabric layer has tighter construction for fiber retention. Each layer's local properties are optimized for its specific function.
3Adaptability or versatility
If thermoplastic belts with diverse openings are used, then opening variety is improved, but strength and durability deteriorate
Solution Approach 1:
The belt is divided into multiple independent layers: a woven fabric layer providing strength and dimensional stability, and a thermoplastic layer providing diverse opening configurations. This segmentation allows each layer to fulfill its specific function without compromise.
Solution Approach 2:
The invention uses a composite structure combining woven fabric material with thermoplastic material. The woven layer contributes tensile strength while the thermoplastic layer contributes opening variety and web interaction properties, achieving synergistic performance.
4Manufacturing precision
If higher caliper is achieved through larger dome structures, then softness is improved, but manufacturing complexity increases
Solution Approach 1:
The invention changes the structural parameters of the belt by introducing a multilayer configuration with specific opening patterns in the thermoplastic layer. This allows dome structures of controlled size and distribution to form during creping, achieving higher caliper through parameter optimization rather than complex processing.
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 multilayer belt structure allows for larger dome structures and higher caliper in paper products, improving softness and bulk while maintaining fiber retention, resulting in paper products with superior properties compared to conventional creping structures.
Implementation Method 1
Subsequent to the creping operation, a vacuum may also be used to further draw the web into the openings in the creping structure.
Implementation Method 2
a woven or extruded polymeric bottom layer for strength and fiber retention, preventing fiber passage while allowing air flow
Data Source
AI summary
An absorbent sheet made by a process that includes the steps of forming a nascent web from an aqueous papermaking furnish, and creping the nascent web on a multilayer belt that includes (i) a first layer made from a polymeric material having a plurality of openings, and (ii) a second layer attached to the first layer, with the nascent web being deposited onto a surface of the first layer. The absorbent sheet includes a plurality of hollow domed regions projecting from a side of the absorbent sheet, with each of the hollow domed regions being shaped such that a distance from at least one first point on an edge of a hollow domed region to a second point on an edge at an opposite side of the hollow domed region is at least about 0.5 mm.