Tissue Product Lotion Application Using In-Line Nip Transfer
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Solution Overview
Problem
Existing methods for applying lotions to absorbent tissue products are complex, expensive, and inefficient, often requiring off-line processes that treat more of the tissue surface than necessary, leading to increased costs and reduced effectiveness in reducing skin irritation.
Innovation Solution
A low-cost, in-line process for selectively treating a fibrous web with a lotion, where the lotion is applied to the uppermost surface of the web in an amount ranging from 0.20 to 3.0 grams per square meter, using a nip between a transfer surface and another surface to transfer the lotion onto the web, ensuring efficient and targeted application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If liquid or lipid-based semi-solid formulations are applied to tissue, then skin irritation is reduced, but high amounts of formulation are required and cost increases
Solution Approach 1:
The patent applies phase transition by using a solid lipid formulation that melts at body temperature. The formulation is applied in solid form to the tissue, then melts upon contact with the user's skin (phase change from solid to liquid), allowing it to spread and provide lubricity. This eliminates the need for high amounts of liquid or semi-solid formulations, as the solid form can be applied in thin layers that transform into effective lubricating layers on skin contact.
Solution Approach 2:
The patent uses a disposable tissue product that is discarded after single use. The solid lipid formulation is applied to the tissue, and both the tissue and formulation are discarded together after one use. This eliminates the need for expensive, complex application equipment or processes, as the formulation is pre-applied to a single-use product. The cost-effectiveness comes from using inexpensive tissue as the delivery vehicle rather than requiring sophisticated application machinery.
2Ease of manufacture
If complex off-line processes like rotogravure printing or spraying are used to apply formulations, then formulation can be applied to tissue surface, but process complexity and cost increase
Solution Approach 1:
The formulation is pre-applied to the tissue during the tissue manufacturing process itself, rather than requiring separate off-line application steps. The solid lipid formulation is incorporated into the tissue web as it is being formed, ensuring uniform distribution without requiring subsequent complex application equipment. This preliminary action integrates the formulation application into the existing tissue production line.
Solution Approach 2:
The patent merges the formulation application process with the tissue manufacturing process. Instead of separate steps for making tissue and then applying formulation, the solid lipid formulation is applied during web formation on the papermaking machine. This combines two processes into one, eliminating the need for complex off-line application equipment and reducing overall process complexity.
3Quantity of substance
If lipid-based solid formulations are heated and applied to tissue surface, then formulation transfers efficiently to skin, but additional heating equipment and process complexity are required
Solution Approach 1:
The patent exploits the parameter change of the lipid formulation's melting point. The formulation is designed to melt at body temperature (approximately 37°C), which is the natural temperature of human skin. When the solid lipid formulation on the tissue contacts the user's skin, it automatically melts and spreads, providing lubricity without requiring external heating. This parameter change (solid to liquid at body temperature) enables efficient transfer and distribution of the formulation using only the user's body heat.
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 process allows for a selective and efficient application of lotion to the tissue surface, reducing skin irritation while minimizing material usage and costs, thereby preserving the tissue's absorbency, strength, and bulk properties.
Implementation Method 1
conveying a web through the nip whereby one outwardly facing surface of the web is contacted by the transfer surface resulting in a transfer of the lotion to the surface of the web
Data Source
Figure 1~1A
Figure 2~2A
Figure 3~5
AI summary
Disclosed is a low-cost, in-line process for treating a fibrous web with a lotion. The process generally involves passing a web through a nip formed by a pair of opposed surfaces, where one of the surfaces has been treated with a lotion having a penetration hardness greater than 5.0 mm. As the web passes through the nip, the lotion is transferred from one of the opposed surfaces to the surface of the web. In certain instances, the web may have a textured surface and only a portion of the web's textured surface is treated with a lotion.