Pulp Filter Paper Draw Resistance and Filtration Balance

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Solution Overview

Problem

Conventional paper filters for cigarettes have different retention properties compared to cellulose acetate filters, leading to undesirable alterations in taste and draw resistance, and existing solutions do not adequately address these issues while maintaining cost-effectiveness.

Innovation Solution

A filter paper composed of at least 80 wt.% long-fiber pulp fibers, with specific fiber dimensions and a controlled fines content, refined using a Papillon refiner to achieve air permeability between 1000 cm min^-1 kPa^-1 and 9000 cm min^-1 kPa^-1, ensuring filtration efficiency and draw resistance similar to cellulose acetate filters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional paper is used as filter material, then cost is reduced and environmental degradation is improved, but filtration efficiency for tar increases excessively and draw resistance decreases too much

Engineering Contradiction:
Improvefiltration efficiencyVSAvoiddraw resistance
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent applies parameter changes by precisely controlling the fiber length distribution (specifically limiting fibers shorter than 0.5mm to 5-20% by number) and air permeability (1500-8000 cm³/min·m²·bar) of the paper filter material. These parameter adjustments optimize the balance between tar filtration efficiency and draw resistance, preventing the excessive filtration and insufficient resistance characteristic of conventional paper filters.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If conventional paper is used as filter material, then cost is reduced and environmental degradation is improved, but taste impression deteriorates due to altered retention properties

Engineering Contradiction:
Improveretention propertiesVSAvoidtaste impression
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent uses parameter changes by controlling the fiber length distribution (5-20% of fibers shorter than 0.5mm by number) and air permeability (1500-8000 cm³/min·m²·bar) to achieve retention properties similar to cellulose acetate filters. This ensures that the paper filter maintains appropriate taste characteristics while preserving the cost and environmental advantages of paper material.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If cellulose acetate is used as filter material, then draw resistance and hardness meet expectations, but cost increases and environmental degradation is worsened

Engineering Contradiction:
Improvedraw resistanceVSAvoidcost
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent applies the principle of using inexpensive, disposable paper material instead of expensive cellulose acetate. By controlling the fiber length distribution and air permeability parameters, the paper filter achieves draw resistance and retention properties comparable to cellulose acetate, thereby reducing cost while maintaining performance and improving environmental degradability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Quantity of substance

If conventional paper filter is used, then cost is reduced, but hardness and resistance to mechanical deformation do not meet expectations

Engineering Contradiction:
ImprovecostVSAvoidhardness
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent applies parameter changes by optimizing the fiber length distribution (5-20% of fibers shorter than 0.5mm by number) and air permeability (1500-8000 cm³/min·m²·bar) of the paper material. These parameter adjustments enhance the mechanical strength and hardness of the paper filter to meet smoker expectations while maintaining the cost advantages of paper material.

Inventive Principle:
Principle #35Parameter changes

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 provides a filter paper that mimics cellulose acetate filters in terms of filtration efficiency and draw resistance, while being cost-effective and environmentally friendly, requiring minimal adjustments to cigarette design.

Implementation Method 1

refined using a Papillon refiner to achieve air permeability between 1000 cm min^-1 kPa^-1 and 9000 cm min^-1 kPa^-1

Methodology Applied
Scientific EffectMechanical refining: Mechanical Force

Implementation Method 2

the filter paper comprises long-fiber pulp fibers... with a specific fiber dimension distribution... air permeability between 1000 cm min^-1 kPa^-1 and 9000 cm min^-1 kPa^-1... filtration efficiency similar to cellulose acetate filters

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP3433427B2Improved filter paper for cigarette filters
Publication Date: 2025.06.25 DELFORTGROUP
  • EP3433427B2 patent drawingFigure 1
  • EP3433427B2 patent drawingFigure 2
  • EP3433427B2 patent drawingFigure 3

AI summary

The invention relates to a filter paper for producing filters for smoking articles, in particular filter cigarettes, having the following properties: the filter paper comprises fibers comprising pulp fibers; at least 80 wt.%, preferably at least 90 wt.%, particularly preferably at least 95 wt.%, and particularly preferably 100 wt.%, of the filter paper is made of long-fiber pulp fibers; 2% to 10%, preferably 3% to 9%, particularly preferably 4% to 8%, of the fibers with respect to the number of fibers have a length of less than 0.2 mm; the air permeability of the filter paper, measured according to ISO 2965:2009, is between 500 cm-min -1kPa-1 and 15000 cm-min -1kPa-1 and preferably between 1000 cm-min-1kPa-1 and 9000 cm-min-1kPa-1; the average length of the fibers in the filter paper with respect to the number of fibers is more than 1 mm and less than 5 mm, preferably more than 2 mm and less than 4 mm; and the average width of the fibers in the filter paper with respect to the number of fibers is between 10 µm and 50 µm, preferably between 20 µm and 40 µm, and particularly preferably between 25 µm and 35 µm.