Degradable Cigarette Filter Pill Multilayer Coating
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Solution Overview
Problem
Existing degradable cigarette filters face issues with rapid catalyst release and foreign object impact on taste due to the quick degradation of cellulose acetate filaments, leading to incomplete hydrolysis and adverse taste effects.
Innovation Solution
A degradable cigarette filter design featuring a pill with a hydrolysis-catalyzing material encapsulated in a water-soluble inner layer and a cellulose acetate outer layer, controlling the release of catalysts to ensure sustained degradation of cellulose acetate without affecting the taste of cigarette smoke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pill with water soluble coating is used to release hydrolysis catalyst, then the catalyst is released quickly and cellulose acetate degradation is initiated, but the catalyst is completely lost before sufficient hydrolysis can occur and the taste of smoke is negatively impacted
Solution Approach 1:
The pill is segmented into multiple layers with different functions: an inner water-soluble coating layer for initial catalyst release, and an outer cellulose acetate layer with D.S. 2.0-2.6 that degrades slowly to provide sustained catalyst release over time, preventing complete catalyst loss before hydrolysis completion
Solution Approach 2:
The invention changes the parameter of catalyst release rate by using a dual-layer structure where the outer cellulose acetate layer with specific D.S. range (2.0-2.6) controls the release kinetics, providing sustained release that matches the hydrolysis rate requirement while maintaining taste quality
2Ease of manufacture
If a simple pill construction is used for catalyst delivery, then manufacturing is simplified, but the pill acts as a foreign object that negatively impacts smoke taste
Solution Approach 1:
The pill uses a composite structure combining water-soluble material and cellulose acetate with D.S. 2.0-2.6, where the outer cellulose acetate layer matches the chemical composition of the filter tow, making the pill indistinguishable from the surrounding material and eliminating foreign object taste impact while maintaining manufacturing simplicity
3Strength
If cellulose acetate with D.S. 2.0-2.6 is used in the filter, then the filter has desired mechanical properties and taste, but the cellulose acetate is not readily attacked by naturally occurring enzymes and bacteria, preventing degradation
Solution Approach 1:
The invention applies preliminary action by incorporating a hydrolysis catalyst that converts cellulose acetate with D.S. 2.0-2.6 into cellulose acetate with D.S. ≤1.0 before biodegradation can occur, enabling the normally resistant material to become vulnerable to enzyme and bacteria attack while maintaining structural integrity during use
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 controlled release of hydrolysis catalysts in the cigarette filter achieves targeted degradation of cellulose acetate within several months, maintaining taste quality and ensuring complete hydrolysis, thus addressing the limitations of previous designs.
Implementation Method 1
the cellulose acetate must be hydrolyzed (i.e., replacement of the acetate moieties with hydroxyl moieties)
Implementation Method 2
a pill dispersed into the tow. These pills comprised the hydrolysis catalyst
Implementation Method 3
an inner layer of a water soluble or water permeable material
Data Source
AI summary
A degradable cigarette filter includes a filter element of a bloomed cellulose acetate tow and a plug wrap surrounding the filter element, and a pill dispersed in the tow. The pill includes a material adapted to catalyze hydrolysis of the cellulose acetate tow that is encapsulated with an inner layer of a water soluble or water permeable material and an outer layer of a cellulose acetate having a D.S. in the range of 2.0-2.6.