Nonwoven Fabric 3D Embossing Below Bonding Temperature
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Solution Overview
Problem
Existing nonwoven fabric production processes face challenges in incorporating three-dimensional embossing in high productivity lines due to temperature uniformity issues with metal rollers, leading to compromised mechanical and chemical-physical properties such as softness and fluffiness.
Innovation Solution
A method involving a calender with two rollers, where the first roller has a thermally conductive material and a pattern, and the second roller has lower hardness, performs embossing at a temperature lower than the bonding temperature to achieve three-dimensional deformation without compromising the fabric's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal rollers are used for embossing at high temperature, then embossing can be performed, but temperature uniformity is compromised leading to poor mechanical and chemical-physical properties
Solution Approach 1:
The patent changes the material parameter of the embossing roller from metal to rubber, which fundamentally alters the thermal properties. Rubber has lower thermal conductivity than metal, enabling more uniform temperature distribution across the roller surface during embossing operations, thus resolving the temperature uniformity issue while maintaining effective embossing temperature
Solution Approach 2:
The patent employs a rubber roller instead of a rigid metal roller for embossing. The flexible rubber material allows for better conformability and more uniform heat distribution across the contact surface, improving temperature uniformity during the embossing process while maintaining the necessary embossing temperature
2Shape
If embossing is performed at bonding temperature, then three-dimensional deformation is achieved, but fiber re-melting occurs compromising softness and fluffiness
Solution Approach 1:
The patent separates the embossing temperature from the bonding temperature, using a lower embossing temperature that is sufficient to achieve three-dimensional deformation without causing fiber re-melting. This temperature parameter differentiation allows the fabric to maintain its softness and fluffiness while still achieving the desired embossed shape
Solution Approach 2:
The bonding process is completed first to establish the fabric structure, then the embossing process is applied at a lower temperature to create the three-dimensional shape. This sequential approach ensures that the fibers are already bonded and won't re-melt during embossing, preserving the fabric's softness and fluffiness
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 method enables three-dimensional embossing in high productivity lines, maintaining the nonwoven fabric's softness and fluffiness by avoiding re-melting of fibers, thus improving mechanical and chemical-physical properties.
Implementation Method 1
the first roller is made of a thermally conductive material and is heated
Implementation Method 2
performing three-dimensional embossing of the bonded substrate at an embossing temperature lower than the bonding temperature
Data Source
Figure 1
Figure 2
Figure 3b~3d
AI summary
A method is provided for obtaining an embossed nonwoven fabric. The method comprises the following steps, performed continuously one after the other: providing a substrate of unbonded fibers of the nonwoven fabric; performing a bonding of the substrate fibers with a thermal process that reaches a bonding temperature at which bonding of the substrate fibers occurs and obtaining a bonded substrate of the nonwoven fabric; and, after the bonding step, performing a three-dimensional type embossing of the bonded substrate at an embossing temperature lower than the bonding temperature and obtaining the embossed nonwoven fabric.