Multi-Ply Tissue Embossing With Split Line-and-Dot Ply Patterns
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Solution Overview
Problem
Existing papermaking processes, such as wet-pressing and through-air drying, struggle to produce tissue products with high bulk, absorbency, and softness while maintaining aesthetic appeal, and embossing methods often result in gritty or stiff products with decreased absorbency.
Innovation Solution
Embossing multi-ply tissue products with different tensile strengths and patterns, specifically a first ply with line emboss elements and a second ply with dot emboss elements, to enhance bulk and aesthetic appeal without compromising physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If embossed patterns are created using conventional calendering or embossing techniques, then the tissue product achieves desired surface texture and bulk, but the embossed pattern disappears after a few manufacturing cycles due to material buildup in the embossing nip
Solution Approach 1:
The tissue web is divided into multiple plies (first ply and second ply) that are embossed separately. Each ply receives the embossed pattern independently through its own embossing nip, preventing material buildup from one ply from affecting the pattern quality on subsequent passes. This segmentation allows each ply to be embossed without interference from other plies, maintaining consistent pattern definition over extended manufacturing cycles.
Solution Approach 2:
The patent transitions from conventional single-nip embossing to a multi-plied structure where embossing occurs in multiple layers/dimensions. By creating embossed patterns in separate plies that are then combined, the system adds a dimensional aspect to the embossing process, allowing the pattern to be established in each ply independently before final assembly, thereby preventing pattern degradation.
2Strength
If multiple plies are combined to form a multi-ply tissue product, then the product achieves improved strength and functionality, but the embossed pattern becomes indistinct or disappears
Solution Approach 1:
The multi-ply structure is designed so that each individual ply maintains its own distinct embossed pattern. Rather than attempting to emboss the combined multi-ply structure (which would cause pattern loss), the patent segments the embossing operation to occur in each ply separately during formation, preserving clear pattern definition in each layer while maintaining the strength benefits of multiple plies.
Solution Approach 2:
The embossed pattern is applied preliminarily to each individual ply during the formation process, before the plies are combined into the final multi-ply product. This preliminary embossing ensures that the pattern is firmly established in each ply's structure before bonding occurs, preventing pattern indistinctness that would result from attempting to emboss the combined structure after assembly.
3Shape
If embossing is performed on conventional single-ply or multi-ply tissue products, then surface texture is improved, but the embossing nip experiences material buildup that degrades pattern quality
Solution Approach 1:
The embossing operation is segmented across multiple plies, with each ply passing through its own embossing nip during formation. This segmentation prevents material buildup in any single nip because each nip processes only one ply at a time, eliminating the cumulative material accumulation problem that occurs in conventional multi-ply embossing where all plies are compressed together through a single nip.
Solution Approach 2:
The embossing action is performed preliminarily during the formation of each individual ply, before the plies are combined. This timing ensures that the embossing nip works on a single, stable ply structure rather than attempting to compress and pattern multiple plies simultaneously, thereby preventing material buildup and reducing maintenance requirements.
Data Source
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AI summary
Disclosed are embossed, multi-ply tissue products having consumer preferred physical properties and an aesthetically pleasing appearance. The products may have a first ply embossed with a first pattern comprising line emboss elements and a second ply embossed with a second embossing pattern comprising dot emboss elements. In addition to having plies with different embossing patterns, the plies may have different tensile strength, such as a first ply having a geometric mean tensile (GMT) strength greater than 500 g/3" and a second ply having a GMT less than 500 g/3". Preferably the difference in the GMT between the first and second plies is at least about 20 percent, such as from about 20 to about 50 percent.