Three-Ply Bath Tissue Bonding Without Harsh Glassining Marks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sanitary tissue products face challenges in achieving softness and aesthetic appeal due to harshness from ply bonding technologies, particularly adhesive use and embossing patterns, which can lead to uneven surfaces and consumer dissatisfaction.
Innovation Solution
A three-ply tissue product is formulated by embossing two heavily embossed plies with a third lightly embossed ply, using a spot glassining process with knurled ply-bonding wheels featuring a sinuous path and soft-shouldered emboss elements to create a durable, tenacious bond without sharp discontinuities, concealing the glassining pattern and avoiding asperities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is used for ply bonding, then effective ply bonding is achieved, but the sheet becomes harsher
Solution Approach 1:
The patent replaces chemical bonding (adhesive) with mechanical bonding (embossing) to join plies together. The embossed plies are mechanically interlocked through complementary embossed patterns, eliminating the need for adhesives that cause harshness while maintaining effective ply bonding through mechanical interengagement of the embossed structures.
Solution Approach 2:
The embossed pattern acts as an intermediary structure between plies, creating a mechanical coupling mechanism. The raised and recessed areas of the embossed pattern provide contact points and interlocking features that bond plies mechanically without requiring chemical adhesives, thus avoiding harshness while ensuring bonding effectiveness.
2Reliability
If plies are joined by embossing, then ply bonding is achieved, but one side of the resulting structure becomes considerably harsher
Solution Approach 1:
The patent employs asymmetrical embossed patterns where the two sides of the multi-ply structure have different embossing characteristics. One side features a more heavily embossed pattern while the other side has a lighter or complementary pattern, creating asymmetry that directs harsher features inward and maintains softer surfaces on the exterior sides of the product.
Solution Approach 2:
Instead of having the harsher embossed surface face outward, the patent inverts the arrangement by positioning the heavily embossed plies internally with their harsher features directed inward toward the center of the multi-ply structure. The exterior surfaces are formed by plies with lighter embossing, thus inverting the expected location of harshness and presenting softer surfaces to the user.
3Reliability
If spot glassining is used with conventional knurled ply-bonding wheels, then tight ply bond is achieved, but unsymmetrical 'railroad track' appearance is created
Solution Approach 1:
The patent uses asymmetrical or random positioning of glassining spots rather than uniform linear patterns. The knurled ply-bonding wheels are configured to create spots at varying locations and orientations, breaking the symmetrical 'railroad track' appearance while maintaining effective ply bonding through distributed spot glassining across the sheet surface.
Solution Approach 2:
The patent applies glassining locally at specific spots rather than uniformly across the entire surface. The knurled wheels create concentrated glassining spots at strategic locations where ply bonding is most needed, while leaving other areas with natural embossed patterns intact, thus maintaining aesthetics while achieving bond tightness at critical points.
4Object-affected harmful factors
If multi-ply construction is adopted to improve softness, then softness is enhanced, but ply separation issues occur
Solution Approach 1:
The patent applies embossing and glassining treatments to the plies before final assembly into the multi-ply structure. The embossed patterns and glassining spots are pre-formed on individual plies or during the bonding process, creating mechanical interlocks and adhesive bonds in advance that prevent separation during subsequent handling and use of the multi-ply product.
Solution Approach 2:
The patent replaces reliance on adhesive bonding alone with mechanical interlocking through embossed patterns. The complementary embossed features on adjacent plies create physical interengagement that resists separation forces, providing mechanical reinforcement to the ply bonding system and preventing delamination without requiring excessive adhesive.
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 solution achieves high levels of consumer acceptance with enhanced softness and opacity, reducing the need for chemical softeners and improving the aesthetic appeal by eliminating the 'railroad track' appearance, while maintaining effective ply bonding and caliper.
Implementation Method 1
the plies are bonded to the third ply to provide an ultra bulky, low sidedness, soft three ply tissue
Implementation Method 2
ply-bonding by spot glassining the embossed plies together with a backing ply
Data Source
AI summary
Visibility of ply-bonding created by glassining spot embossing on decorative pattern embossed tissue products is provided by obscuring the glassined spot embosses by distributing them along a meandering path through the decorative pattern, obscuring the edges of the glassined spot embosses by providing a gradual transition therefrom and combinations of the two techniques.