Absorbent Article Top Sheet Wrinkle Prevention via Localized Joint Patterns
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Solution Overview
Problem
Absorbent articles face the challenge of MD direction wrinkles during the production of top sheets with extruded projections, which affect the appearance and functionality of the final product.
Innovation Solution
The formation of dot-like top-second joint portions at CD-direction central positions between adjacent extruded projections, with joint patterns that are intermittent in the width and front-back directions, and have wider or stepwise MD direction joint ranges increasing towards the lateral sides, helps in smoothing out vertical wrinkles without deforming the extruded projections during the joining process with the second sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the top sheet and second sheet are joined using conventional joining methods, then the extruded projections are securely maintained, but MD direction wrinkles are formed along the machine direction
Solution Approach 1:
The joining is divided into multiple discrete top-second joint portions arranged in a specific pattern rather than continuous joining. These joint portions are positioned at intervals between adjacent extruded projections, segmenting the joining process to prevent wrinkle formation while maintaining projection integrity
Solution Approach 2:
The joint portions are strategically positioned only in specific locations between extruded projections rather than across the entire surface. This local joining approach applies bonding only where necessary to secure the sheets while leaving other areas untouched to prevent wrinkle formation
2Reliability
If the top sheet is embossed with extruded projections to prevent reflowing, then absorbability and appearance are improved, but wrinkles are formed during the joining process
Solution Approach 1:
The embossing process creating extruded projections is performed before the joining process. This preliminary action establishes the functional surface structure that prevents reflowing, and the subsequent joining is carefully designed to accommodate these projections without causing wrinkles
Solution Approach 2:
The joining is applied locally in specific patterns that accommodate the embossed structure. Joint portions are positioned to avoid interfering with the extruded projections while still providing adequate bonding between sheets
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
This approach effectively prevents MD direction wrinkles in the top sheet, enhancing the appearance and maintaining the functionality of the absorbent articles by ensuring smooth integration with the second sheet without compromising the extruded projections.
Implementation Method 1
The top sheet material 30S and the second sheet material 40S are sandwiched between the concave roll 91 and the joint roll 92, and are thermally pressed and attached between the joint convex portions 91b of the concave roll 91 and the outer peripheral surface of the joint roll 92
Data Source
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AI summary
An object of the present invention is to join a top sheet having extruded projections and a second sheet while preventing occurrence of MD direction wrinkles in the top sheet. The foregoing object is achieved by a method for producing an absorbent article including: while conveying non-woven fabric (30S) to be a top sheet (30) by drawing from the downstream side, forming extruded projections (31) by embossing; placing a material for a second sheet (40) on the back surface of the non-woven fabric with the extruded projections (31); and joining the non-woven fabric and the material (40S) for the second sheet (40) in a joint pattern in which top-second joint portions (80) are formed between the MD direction adjacent extruded projections (31) at CD direction central positions corresponding to CD direction central portions of the adjacent extruded projections (31) and at lateral positions on the CD -direction both sides of the central positions, and a MD direction joint range (A1 and A2) of the top-second joint portions (80) is wider continuously or stepwise with increasing proximity from the central position to the lateral sides.