Process for manufacturing of a robust, flexible waxed web material
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Solution Overview
Problem
Existing methods for coating flexible sheet-like substrates with waxy materials face challenges such as tackiness, machine contamination, and limited ability to add substantial pharmaceutically active compounds, leading to inefficient and troublesome production processes, particularly in manufacturing disposable absorbent articles like tampons.
Innovation Solution
A process involving applying a waxy composition comprising monoesters or diesters of polyhydric aliphatic alcohols and fatty acids, combined with a diluent, to a flexible substrate, followed by cooling using a chiller with a liquefied gas source below -100 °C, to form a stable and robust coated material that minimizes handling issues and machinery interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If waxy materials are applied to flexible substrates to achieve robust coating, then coating stability and robustness are improved, but the coated sheets become tacky and stick to machine parts causing contamination and process interruption
Solution Approach 1:
The patent applies a waxy composition that is liquid at processing temperatures (35-100°C) but solidifies at lower temperatures. By controlling the temperature parameter during application and storage, the coating transitions from a liquid state (easy to apply, non-tacky) to a solid state (robust, non-sticky), resolving the contradiction between coating robustness and tackiness
Solution Approach 2:
The waxy composition is formulated as a composite material containing waxy compounds (monoesters/diesters of polyhydric aliphatic alcohols and fatty acids) combined with diluents and other additives. This composite structure allows the coating to exhibit liquid properties during application and solid properties during storage and use, eliminating both tackiness and machine contamination while maintaining robustness
2Quantity of substance
If substantial amounts of pharmaceutically active compound are added to the substrate to form robust coated material, then therapeutic efficacy is improved, but the ability to form stable coated material is limited
Solution Approach 1:
The patent utilizes temperature as a critical parameter to control the state of the waxy composition. At application temperatures (35-100°C), the composition remains liquid, allowing substantial amounts of pharmaceutically active compounds to be incorporated uniformly. Upon cooling, the composition solidifies, stabilizing the coating and preventing migration or separation of the active compounds, thus achieving both high loading and stability
Solution Approach 2:
The waxy composition acts as an intermediary carrier matrix that encapsulates and stabilizes pharmaceutically active compounds. This intermediary structure allows high concentrations of active compounds to be incorporated while maintaining coating integrity and stability through the phase transition mechanism, solving the contradiction between quantity and stability
3Temperature
If conventional cooling methods are used for wax impregnated web, then cooling is achieved, but the process requires multiple cooling zones and extended processing time
Solution Approach 1:
The patent employs a single chiller unit that cools the waxed web to below -100°C, utilizing the substantial temperature differential to achieve rapid and complete solidification of the waxy composition in one step. This eliminates the need for multiple cooling zones with gradual temperature reductions, simplifying the cooling system while effectively solidifying the coating
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 process enables efficient, trouble-free manufacturing of coated sheets with improved handling and processing capabilities, allowing for the production of robust, flexible materials suitable for use in disposable absorbent articles that maintain their integrity and functionality.
Implementation Method 1
cooling the waxed web
Implementation Method 2
The coating forms a stable liquid mixture at a temperature between about 35 °C and about 100 °C, has a liquefaction temperature of at least about 30 °C
Data Source
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AI summary
A process for manufacturing robust, flexible sheet-like material, includes the steps of a) applying a waxy composition to the web to form a waxed web; b) leading the waxed web via at least one roller to a chiller; c) cooling the waxed web; and d) leading the waxed web to a collection station for collecting the waxed web for further processing. The waxy composition comprises about 10-60 wt-% of a waxy compound and about 90-40 wt-% of a diluent. The waxy compound is selected from the group consisting of A) monoesters of a polyhydric aliphatic alcohol and a fatty acid; B) diesters of a polyhydric aliphatic alcohol and a fatty acid; and C) mixtures of said monoesters and diesters.