Soft Nonwoven Web Layered Structure Necking Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonwoven webs made from certain polyolefin blends, such as polypropylene with a propylene copolymer and a softness enhancer additive, are prone to excessive necking, which increases material costs and processing difficulties due to reduced length in the cross-direction, affecting their mechanical properties and tactile feel.
Innovation Solution
A nonwoven web structure comprising at least two fibrous layers with different compositions, where one layer includes fibers made of a blend of polypropylene with a propylene copolymer and a softness enhancer additive, and the second layer has distinct mechanical properties, reducing necking by incorporating less than 10% propylene copolymer by weight, thereby enhancing tactile properties and mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a nonwoven web is made from a blend of polypropylene with propylene copolymer and softness enhancer additive, then tactile properties and perceived softness are improved, but necking increases causing reduction in cross-direction length
Solution Approach 1:
The nonwoven web is divided into multiple layers with different fiber compositions. The first layer contains the polypropylene blend with softness enhancer for tactile comfort, while the second layer uses different composition to provide structural stability and reduce necking. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions (layers) of the nonwoven web are given different properties. The first layer is optimized for softness and tactile feel, while the second layer is optimized for mechanical strength and resistance to necking. This local differentiation resolves the contradiction by allowing each property to be optimized in its appropriate location.
2Strength
If a nonwoven web is made from a blend of polypropylene with propylene copolymer and softness enhancer additive, then perceived softness is improved, but manufacturing cost increases
Solution Approach 1:
The web is segmented into layers with different compositions. The expensive softness-enhancing blend is used only in the first layer where tactile comfort is needed, while the second layer uses a more cost-effective composition. This reduces overall material cost while maintaining the required softness perception.
Solution Approach 2:
The composition parameters are changed between layers. The first layer uses a higher proportion of softness enhancer additive, while the second layer uses less or different composition. This parameter variation allows cost optimization while preserving the essential tactile properties in the consumer-facing layer.
3Strength
If a nonwoven web is made from a blend of polypropylene with propylene copolymer and softness enhancer additive, then tactile properties are improved, but processability deteriorates due to necking
Solution Approach 1:
The web structure is segmented into functional layers. The first layer provides tactile properties, while the second layer with different composition provides dimensional stability during processing. This segmentation improves processability by reducing necking while maintaining tactile quality.
Solution Approach 2:
The nonwoven web is constructed as a composite of two different fiber compositions. This composite structure combines the tactile benefits of the polypropylene blend with the processing stability of the second layer, resolving the contradiction between tactile properties and ease of manufacture.
Data Source
Figure 1~2
Figure 3
Figure 4A
AI summary
A product that includes a soft nonwoven web is disclosed. The nonwoven web includes a first fibrous layer made of a first composition and a second fibrous layer made of a second composition. The second composition is different from the first composition.