EP-4444116-B1 - METHOD FOR MANUFACTURING A VENTILATION ZONE IN AN AEROSOL- GENERATING ARTICLE

Inventors

• GRAF, Didier Bernard
• LHAOU, Ayoub
• LOUVET, Alexis Julien
• BOSI, Luca
• SCAGNELLI, Marco
• BATTISTA, FEDERICO
• ZINNA, Maria Sole
• HOFFMANN, HANS-REINER

Dates

Publication Date

20260513

Application Date

20221207

Claims (14)

1. Method for manufacturing a first ventilation zone in a first aerosol-generating article (10) and a second ventilation zone in a second aerosol-generating article, comprising the method steps: A) providing a first aerosol-generating article (10), B) forming first perforations in the first aerosol-generating article (10), thereby creating a first ventilation zone (12), C) determining the first air infusion value for the first aerosol-generating article (10), the air infusion value being determined by the equation (P in -P out )•100%/P in , wherein P in is an air pressure of between 5 millibars and 50 millibars applied at the first end face (11A) of the article and P out is an air pressure detected at the second end face (11B) of the article, D) comparing said first air infusion value to a reference value, E) providing the second aerosol-generating article and forming second perforations in the second aerosol-generating article, thereby creating the second ventilation zone, wherein a size of the second perforations is adjusted based on the comparison between the determined first air infusion value and the reference value, wherein during method step C) an air blast is applied as air pressure to the first aerosol-generating article for a time period of between 25 milliseconds to 60 milliseconds and the pressure difference is measured between both opposing first and second end faces of the first aerosol-generating article as indicated by the equation above.
2. Method according to any of the preceding claims, wherein a first continuous rod (11) is provided as a first aerosol-generating article and wherein a second continuous rod is provided as a second aerosol-generating article, wherein the first continuous rod (11) and the second continuous rod includes at least two aerosol-generating articles, preferably wherein the first continuous rod and the second continuous rod consists of two aerosol-generating articles.
3. Method according to any of the preceding claims for manufacturing a first ventilation zone in a predetermined first number of first aerosol-generating articles, wherein during the method steps A) and B) the predetermined first number of first aerosol-generating articles is provided and wherein first perforations are formed in each of the first aerosol-generating articles of the predetermined first number of first aerosol-generating articles and wherein during method step C) the individual first air infusion values of the first aerosol-generating articles are determined and wherein an average first air infusion value thereof is calculated.
4. Method for manufacturing according to any of the preceding claims, wherein the reference value is a target air infusion value for the first and second aerosol-generating article.
5. Method for manufacturing of any of the preceding claims, wherein in a method step A2) before method step B) a first resistance-to-draw RTD value of the first aerosol-generating article is measured in accordance with ISO 6565-2015, more preferably wherein the RTD value is measured by applying a constant air flow to the first end face of the first aerosol-generating article and measuring the increase in air pressure at said first end face of the first aerosol-generating article due to the air resistance of the article.
6. Method according to the preceding claim further dependent on claim 3, wherein individual first RTD values are determined for each of the first aerosol-generating articles of the predetermined first number of first aerosol-generating articles.
7. Method for manufacturing according to the preceding claim, wherein the individual first air infusion values of the first aerosol-generating articles determined in step C) are corrected on the basis of the first individual resistance-to-draw (RTD) values, thereby providing corrected individual first air infusion values and wherein an average corrected first air infusion value is calculated based on the corrected individual first air infusion values.
8. Method of manufacturing according to the preceding claim, wherein in step E) the average corrected first air infusion value is compared to the reference value and wherein in step E) the size of the second perforations is adjusted based on the comparison between the average corrected first air infusion value and the reference value.
9. Method according to the preceding claim further according to claim 6, wherein an average first RTD value is calculated from the individual first RTD values of the first aerosol-generating articles and wherein an average second RTD value is calculated from individual second RTD values of the second aerosol-generating articles of the predetermined second number of first aerosol-generating articles.
10. Method according to the preceding claim wherein the reference value is set in method step D) depending on the RTD value measured for the first aerosol-generating article in method step A2).
11. Method for manufacturing an aerosol-generating article of any of the preceding claims 3, 6 and 7, wherein the predetermined first number of aerosol-generating articles is the same as the predetermined second number of aerosol-generating articles, preferably wherein the predetermined first and second number of aerosol-generating articles is at least 50, preferably at least 100, more preferably at least 1000 aerosol-generating articles.
12. Method of manufacturing according to any of the preceding claims, wherein in step E) the size of the second perforations is one of decreased or increased in comparison to the size of the first perforations.
13. Method for manufacturing of any of the preceding claims, wherein during method step B) slits or ovals are formed as first perforations, the first perforations having a width and a length, and wherein during method step E) the length of the second perforations is adjusted.
14. Method for manufacturing of any of the preceding claims, wherein during method step A) a first aerosol-generating article is provided, wherein the first aerosol-generating article comprises a first hollow tube section and a first substrate section, preferably wherein the first aerosol-generating article further comprises a first filter section.

Description

The present invention relates to a method for manufacturing a ventilation zone in an aerosol-generating article. The aerosol-generating article may comprise an aerosol-forming substrate and may be adapted to produce an inhalable aerosol upon heating. Aerosol-generating articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than combusted, are known in the art. Typically, in such heated smoking articles an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-forming substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol. Aerosol-generating articles with a ventilation zone including perforations are known. These ventilation zones allow ambient air to enter the aerosol-generating article during a user's puff. This enables a better mixing of the air flow coming from the aerosol-forming substrate with the ambient air for facilitating the formation of an aerosol. The amount of air which may enter the aerosol-generating article during the user's puff depends on the number, positions and the shape of the perforations. These perforations may be hard to form with low variability during a high-speed manufacturing process for the aerosol-generating articles. A large quantity of aerosol-generating articles including the ventilation zones may be difficult to manufacture without great variations with regard to important characteristics of the aerosol-generating articles, such as to the amount of air, which can enter the aerosol-generating articles through the ventilation zone. Differences in the characteristics of the aerosol-forming substrate of the large quantity of aerosol-generating articles to be manufactured may also cause differences in the characteristics of the aerosol-generating articles. EP 0 543 561 A2 describes a cigarette making machine which is provided with a pressure drop measuring unit. It would be desirable to provide a method for manufacturing a ventilation zone in an aerosol-generating article in order to manufacture an aerosol-generating article that can be operated efficiently and at high speed. It furthermore would be desirable to provide a method for manufacturing a ventilation zone in an aerosol-generating article, providing aerosol-generating articles with a low variability of the air infusion value from one article to another. It also would be desirable to provide a method for manufacturing a ventilation zone in different aerosol-generating articles, wherein these different aerosol-generating articles exhibit comparable characteristics. According the present invention, there is provided a method for manufacturing a first ventilation zone in a first aerosol-generating article and a second ventilation zone in a second aerosol-generating article, comprising the method steps A) providing a first aerosol-generating article. The method also comprises the method step B) forming first perforations in the first aerosol-generating article, thereby creating a first ventilation zone. The method furthermore comprises the method step C) determining a first air infusion value for the first aerosol-generating article, the first air infusion value being determined by the equation (Pin-Pout)•100%/Pin, wherein Pin is an pressure of between 5 millibars and 50 millibars applied to the article to the first end face and Pout is an air pressure detected at the second end face of the article. The method also comprises the method step D) comparing said first air infusion value to a reference value. A method step E) providing the second aerosol-generating article and forming second perforations in the second aerosol-generating article, thereby creating the second ventilation zone is also included. The size of the second perforation is adjusted based on the comparison between the determined first air infusion value and the reference value in method step E). During method step C) an air blast is applied as air pressure to the first aerosol-generating article for a time period of between 25 milliseconds to 60 milliseconds and the pressure difference is measured between both opposing first and second end faces of the first aerosol-generating article as indicated by the equation above. This method for manufacturing a ventilation zone may enable the manufacturing of aerosol-generating articles having more uniform first and second perforations in the first and second ventilation zone. This may provide aerosol-generating articles having a low air infusion value variability between the first aerosol-generating article and the second aerosol-generating article. This may provide a plurality of aerosol-g