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EP-4740760-A1 - FILTER COMPRISING A PAPER SUBSTRATE COMPRISING A MONOLAYER BASE WEB WITH DIFFERENT FIBROUS PORTIONS

EP4740760A1EP 4740760 A1EP4740760 A1EP 4740760A1EP-4740760-A1

Abstract

The invention relates to a filter comprising a paper substrate as filter media, in particular a filter for a smoking or vaping article

Inventors

  • NIEDERHUBER, Armin
  • LEON, Romuald

Assignees

  • Neenah Gessner GmbH
  • SWM Holdco Luxembourg

Dates

Publication Date
20260513
Application Date
20241107

Claims (14)

  1. Filter comprising a paper substrate as a filter media, said paper substrate comprising a monolayer base web having a first portion and a second portion, the first portion and the second portion being disposed next to each other along a thickness direction of the monolayer base web, wherein the fibers of the first portion are intermeshed with the fibers of the second portion in a transition zone, wherein the second portion comprises more fibers, in terms of mass per unit area, than the first portion, wherein the density of the paper substrate is from 200 mg/cm 3 to 300 mg/cm 3 .
  2. Filter according to claim 1, wherein the air permeability of the paper substrate is higher than 4000 Coresta Unit (CU).
  3. Filter according to claim 1 or claim 2, wherein the thickness of the paper substrate is from 100 µm to 200 µm.
  4. Filter according to any of claims 1 to 3, wherein the basis weight of the paper substrate is from 25 to 55 g/m 2 .
  5. Filter according to any of claims 1 to 4, wherein the tensile strength ratio MD/CD of the paper substrate is from 2 to 3.2.
  6. Filter according to any of claims 1 to 5, wherein the fibers of the first portion are curled fibers and the fibers of the second portion are uncurled fibers.
  7. Filter according to any of claims 1 to 6, wherein the fibers of the first portion and the fibers of the second portion are, independently from each other, wood fibers, natural fibers or combinations thereof.
  8. Filter according to any one of Claims 1 to 7 for a smoking article or a vaping article.
  9. Smoking article comprising a filter as defined in Claim 8.
  10. Vaping article comprising a filter as defined in Claim 8.
  11. Process for producing a paper substrate as defined in any one of claims 1 to 7, comprising the following steps: a1) forming a monolayer base web on a substrate, and b1) removing the monolayer base web from the substrate to produce the paper susbtrate.
  12. Process according to claim 11, wherein step a1) comprises the following sub-steps: a111) wet laying the first portion on the substrate by disposing a first slurry containing fibers on the substrate and, while the first portion is still wet, wet laying the second portion on the first portion, to allow intermeshing of the fibers in the first portion with the second portion, and then a112) removing liquid from the first and second portions to form the monolayer base web.
  13. Process according to claim 11, wherein step a1) comprises the following sub-steps: a121) wet laying the second portion on the substrate by disposing a second slurry containing fibers on the substrate and, while the second portion is still wet, wet laying the first portion on the second portion, to allow intermeshing of the fibers in the first portion with the second portion, and then a122) removing liquid from the first and second portions to form the monolayer base web.
  14. Process for producing a filter as defined in claim 8 for a smoking article or vaping article, comprising the following steps: a2) forming a rod from the paper substrate produced by the process for producing a paper substrate as defined in claim 11 or claim 12, b2) wrapping the rod with a sheet of plug wrap paper, and c2) depositing an adhesive line at the junction of the sheet of plug wrap paper to obtain a rod of filtering material, and d2) cutting the rod of filtering material to produce the filter.

Description

Technical Field The invention relates to the filter comprising a paper substrate as filter media, in particular the filter for a smoking or vaping article. Background Art A filter for a smoking or vaping article has a right circular cylindrical shape and generally comprises an outer envelope of plug wrap paper and a substrate located within the outer envelope. The filter for a smoking or vaping article, by virtue of the substrate, makes it possible to prevent the user from inhaling tobacco particles and allows retention of the harmful particulate substances contained in the smoke or the aerosol, such as tar. Conventional filters comprise cellulose acetate tow. Said conventional filters are also known as cellulose acetate filters. The cellulose acetate filters have a nicotine retention capacity such that the user's perception of the filtered smoke is satisfactory. However, the cellulose acetate filters degrade very slowly and have negative impact on the environment. Indeed, the filter is not consumed during the smoking/vaping of a smoking/vaping article and is regularly found in the environment. Cellulose acetate filters thus have a significant environmental impact. To limit the environmental impact of cellulose acetate filters, it has been proposed to replace the cellulose acetate tow with a paper substrate obtained by a wetlaid process. As the paper substrates are biodegradable, the filters comprising a paper substrate degrade rapidly. However, the filters comprising a paper substrate have higher filtration efficiency, in particular higher nicotine retention capacity, and lower hardness than cellulose acetate filters. Since the nicotine retention capacity is higher, then the perception of the filtered smoke by the user may not be satisfactory. Accordingly, the user experience provided by the filters comprising a paper substrate is not as satisfactory as the user experience provided by the cellulose acetate filters. Technical problem There is therefore a need for a paper substrate which can be used as a filter media and enables the manufacture of a filter for a smoking article or a vaping article and which has a nicotine retention capacity which tends towards the nicotine retention capacity of a cellulose acetate filter. In other words, there is a need for a paper substrate which provides to the user of a smoking or vaping article a satisfactory experience. It is thus to the credit of the inventors to have found that it was possible to meet this need by means of a paper substrate comprising a monolayer base web with different fibrous portions. Summary It is proposed a filter comprising a paper substrate as a filter media, said paper substrate comprising a monolayer base web having a first portion and a second portion, the first portion and the second portion being disposed next to each other along a thickness direction of the monolayer base web, wherein the fibers of the first portion are intermeshed with the fibers of the second portion in a transition zone,wherein the second portion comprises more fibers, in terms of mass per unit area, than the first portion,wherein the density of the paper substrate is from 200 mg/cm3 to 300 mg/cm3, in particular from 220 mg/cm3 to 270 mg/cm3, more particularly from 230 mg/cm3 to 260 mg/cm3. Unexpectedly, in comparison to a standard paper filter, the nicotine retention capacity of the filter of the invention is advantageously improved as it tends towards the nicotine retention capacity of a cellulose acetate filter. Moreover, the difference between the hardness of the filter of the invention and the hardness of a cellulose acetate filter is unexpectedly lower than the difference between the hardness of a standard paper filter and the hardness of cellulose acetate filter. Without wishing bound to any theory, the inventors are of the opinion that these two improvements may be due to the density of the paper substrate since said density is lower than the density of a conventional paper substrate used in the standard paper filters, i.e. about 429 mg/cm3. Indeed, the probability that nicotine of the smoke or aerosol interacts with the fibers decreases as the density decreases. Moreover, a lower density requires to more compact the paper substrate to manufacture filters having the same weight as the conventional cellulose acetate filters, thereby increasing the hardness of the filters. According to another aspect, it is proposed a process for producing a paper substrate as defined above, comprising the following steps: a1) forming a monolayer base web on a substrate, andb1) removing the monolayer base web from the substrate to produce the paper susbtrate. According to another aspect, it is proposed a process for producing a filter as defined above for a smoking article or vaping article, comprising the following steps: a2) forming a rod from the paper substrate produced by the process for producing a paper substrate as defined above,b2) wrapping the rod with a sheet of plug w