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US-20260123662-A1 - FILTER COMPRISING A PAPER SUBSTRATE COMPRISING A MONOLAYER BASE WEB WITH DIFFERENT FIBROUS PORTIONS

US20260123662A1US 20260123662 A1US20260123662 A1US 20260123662A1US-20260123662-A1

Abstract

Filters and filter media are provided that comprise a paper substrate. Methods of making the filters and filter media, and products containing the filter, such as smoking articles and vaping articles, are also provided. The paper substrate comprises a monolayer base web having a first portion and a second portion. the first portion and the second portion are disposed adjacent each other along a thickness direction of the monolayer base web. The fibers of the first portion are intermeshed with the fibers of the second portion in a transition zone. The second portion may comprise more fibers, in terms of mass per unit area, than the first portion. the density of the paper substrate may be from about 200 mg/cm 3 to about 300 mg/cm 3 .

Inventors

  • Armin Niederhuber
  • Romuald LEON

Assignees

  • NEENAH GESSNER GMBH
  • SWM HOLDCO LUXEMBOURG

Dates

Publication Date
20260507
Application Date
20251106
Priority Date
20241107

Claims (20)

  1. 1 . A filter media comprising: a paper substrate, the paper substrate comprising a monolayer base web having a first portion and a second portion, the first portion and the second portion being disposed adjacent 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; and wherein the density of the paper substrate is from 200 mg/cm 3 to 300 mg/cm 3 .
  2. 2 . The filter media of claim 1 , wherein the air permeability of the paper substrate is greater than 4000 Coresta Unit (CU).
  3. 3 . The filter media of claim 1 , wherein the thickness of the paper substrate is about 100 μm to about 200 μm.
  4. 4 . The filter media of claim 1 , wherein the basis weight of the paper substrate is about 25 to about 55 g/m 2 .
  5. 5 . The filter media of claim 1 , wherein the tensile strength ratio MD/CD of the paper substrate is about 2 to about 3.2.
  6. 6 . The filter media of claim 1 , wherein the fibers of the first portion are curled fibers and the fibers of the second portion are uncurled fibers.
  7. 7 . The filter media of claim 6 , wherein the curled fibers have a spiral or helical shape.
  8. 8 . The filter media of claim 1 , wherein the fibers of the first portion and the fibers of the second portion are selected from the group consisting of wood fibers, natural fibers and combinations thereof.
  9. 9 . The filter media of claim 1 , wherein the paper substrate has a specific volume of about 4.5 cm 3 /g to about 9 cm 3 /g.
  10. 10 . The filter media of claim 1 , wherein a weight ratio between fibers of the first portion to fibers of the second portion is about 20:80.
  11. 11 . The filter of claim 10 , wherein the weight ratio is about 40:60.
  12. 12 . A filter comprising the filter media of claim 1 .
  13. 13 . The filter of claim 12 for use with a smoking article or a vaping article.
  14. 14 . A smoking or vaping article comprising: a filter media comprising a paper substrate, the paper substrate comprising a monolayer base web having a first portion and a second portion, the first portion and the second portion being disposed adjacent 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; and wherein the density of the paper substrate is from 200 mg/cm 3 to 300 mg/cm 3 .
  15. 15 . A method for producing a paper substrate comprising: forming a monolayer base web on a substrate; and removing the monolayer base web from the substrate to produce the paper substrate.
  16. 16 . The method of claim 15 , further comprising: wet laying a 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 a second portion on to the first portion to allow intermeshing of the fibers in the first portion with the second portion.
  17. 17 . The method of claim 16 , further comprising removing liquid from the first and second portions to form the monolayer base web.
  18. 18 . The method of claim 15 , further comprising: 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.
  19. 19 . The method of claim 18 , further comprising: removing liquid from the first and second portions to form the monolayer base web.
  20. 20 . The method of claim 15 , further comprising: forming a rod from the paper substrate produced by the process for producing a paper substrate: wrapping the rod with a sheet of plug wrap paper; depositing an adhesive line at the junction of the sheet of plug wrap paper to obtain a rod of filtering material; and cutting the rod of filtering material to produce the filter.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of European Patent Application No. EP24306871.5, filed Nov. 7, 2024, the complete disclosure of which is incorporated herein by reference for all purposes. BACKGROUND The description generally relates to a filter comprising a paper substrate as filter media, in particular the filter for a smoking or vaping article. 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. 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. SUMMARY This following is intended merely to introduce a simplified summary of some aspects of one or more embodiments of the subject matter discussed herein. Further areas of applicability of the subject matter will become apparent from the detailed description provided hereinafter. This summary is not an extensive overview, nor is it intended to identify key or critical elements of the present teachings, nor to delineate the scope of the subject matter. Rather, its purpose is merely to present one or more concepts in simplified form as a prelude to the detailed description below. Filters and filter media are provided that comprise a paper substrate. Products containing the filter, such as smoking articles and vaping articles, are also provided. In one aspect, a filter media comprises a paper substrate comprises a monolayer base web having a first portion and a second portion. the first portion and the second portion are disposed adjacent each other along a thickness direction of the monolayer base web. The fibers of the first portion are intermeshed with the fibers of the second portion in a transition zone. The second portion may comprise more fibers, in terms of mass per unit area, than the first portion. The density of the paper substrate may be from about 200 mg/cm3 to about 300 mg/cm3. In embodiments, the density of the paper is about 220 mg/cm3 to about 270 mg/cm3, or about 230 mg/cm3 to about 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, Applicant believes that these two improvements may be due to the density of the paper substrate since this 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 m