Paper filter

Abstract

A mouthpiece, filter or filter element comprising a longitudinally extending core of paper or other biodegradable (e.g., non-cellulose acetate containing) filtering material, a first wrapper engaged around the peripheral surface of the core, and a second wrapper engaged around the first wrapper, the first wrapper defining at least with the second wrapper a plurality of channels extending longitudinally from the upstream end of the mouthpiece, filter or filter element and/or a plurality of channels extending longitudinally from the downstream end of the mouthpiece, filter or filter element.

1 . A mouthpiece, filter or filter element comprising a longitudinally extending core of paper or other biodegradable (e.g., non-cellulose acetate containing) filtering material, a first wrapper engaged around the peripheral surface of the core, and a second wrapper engaged around the first wrapper, the first wrapper defining at least with the second wrapper a plurality of channels extending longitudinally from the upstream end of the mouthpiece, filter or filter element and/or a plurality of channels extending longitudinally from the downstream end of the mouthpiece, filter or filter element. 
     
     
         2 . A mouthpiece, filter or filter element comprising a longitudinally extending core of paper or other biodegradable (e.g., non-cellulose acetate containing) filtering material, a first wrapper engaged around the peripheral surface of the core, and a second wrapper engaged around the first wrapper, the first wrapper defining at least with the second wrapper a plurality of channels extending longitudinally of the mouthpiece, filter or filter element and which (e.g., extend only part of the core length and) do not extend from either the upstream or downstream ends of the mouthpiece, filter or filter element. 
     
     
         3 . The mouthpiece, filter or filter element according to  claim 1  wherein the channels extend only part of the length of the core. 
     
     
         4 . The mouthpiece, filter or filter element according to  claim 1  wherein at least one longitudinally extending portion of the mouthpiece, filter or filter element includes no channels within its cross-section. 
     
     
         5 . The mouthpiece, filter or filter element according to  claim 1  wherein the channels extend the full length of the core. 
     
     
         6 . The mouthpiece, filter or filter element according to  claim 1  wherein the length the channels is from 5 mm to 30 mm, e.g., from 9 mm to 25 mm. 
     
     
         7 . The mouthpiece, filter or filter element according to  claim 1  wherein the depth of each channel is from 0.5 mm to 2.6 mm for example from 0.8 to 2.2 mm, for example from 1.3 to 2.1 mm, preferably from 1.35 to 2 mm, for example from 1.4 to 1.9 mm. 
     
     
         8 . The mouthpiece, filter or filter element according to  claim 1  wherein the width (e.g. maximum width) of each channel is from 1.0 to 3.0 mm, for example from 1.3 to 2.1 mm, preferably from 1.35 to 2 mm, for example from 1.4 to 1.9 mm. 
     
     
         9 . The mouthpiece, filter or filter element according to  claim 1  including from 5 to 25 channels, preferably from 10 to 16 channels, extending longitudinally from the upstream end of the mouthpiece, filter or filter element and/or from 5 to 25 channels, preferably from 10 to 16 channels, extending longitudinally from the downstream end of the mouthpiece, filter or filter element. 
     
     
         10 . The mouthpiece, filter or filter element according to  claim 1  wherein the total cross-sectional area of the channels extending longitudinally from the upstream end and/or downstream end of the mouthpiece, filter or filter element amounts to from 2 to 12%, preferably from 4 to 8%, of the overall cross-sectional area of the mouthpiece, filter or filter element. 
     
     
         11 . The mouthpiece, filter or filter element according to  claim 1  wherein the first wrapper is a paper (e.g., plugwrap) of basis weight from 60 to 100 gsm, e.g., a paper (e.g., plugwrap) of basis weight from 70 to 90 gm, e.g., a paper (e.g., plugwrap) of basis weight 80 gsm. 
     
     
         12 . The mouthpiece, filter or filter element according to  claim 1  wherein the first wrapper is air permeable. 
     
     
         13 . The mouthpiece, filter or filter element according to  claim 1  wherein the first wrapper has longitudinally extending corrugations (e.g., grooves and ridges) which define with the second wrapper the channels extending longitudinally of the filter. 
     
     
         14 . The mouthpiece, filter or filter element according to  claim 1  wherein the second wrapper is a paper (e.g., plugwrap) of basis weight from 25 to 140 gsm, e.g., a paper (e.g., plugwrap) of basis weight from 70 to 90 gm, e.g., a paper (e.g., plugwrap) of basis weight 80 gsm. 
     
     
         15 . The mouthpiece or filter or filter element according to  claim 1  comprising plurality of further channels defined by the first wrapper and at least the second wrapper which extends longitudinally of the core and which extends only part of the length of the core but which does not extend from either the upstream or downstream ends of the core. 
     
     
         16 . The mouthpiece, filter or filter element according to  claim 1  wherein the paper filtering material and/or other biodegradable (e.g., non-cellulose acetate containing) filtering material is standard paper, non-woven paper, airlaid paper, carbon impregnated paper or cellulose/lyocell/viscose based papers. 
     
     
         17 . The mouthpiece, filter or filter element according to  claim 1  wherein the paper filtering material and/or other biodegradable (e.g., non-cellulose acetate containing) filtering material is a non-plastic plant based fibre (e.g., flax, hemp, jute, sisal, abaca, coconut, bamboo, starch or wood pulp or a blend of these materials). 
     
     
         18 . The mouthpiece, filter or filter element according to  claim 1  wherein the length of the mouthpiece, filter or filter element is from 12 to 30 mm, e.g., from 15 to 28 mm, e.g., from 18 to 26 mm, e.g., from 20 to 24 mm. 
     
     
         19 . The mouthpiece or filter element according to  claim 1  wherein the mouthpiece or filter element has greater than 90% biodegradability as measured according to IS014855-1 Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions—Method by analysis of evolved carbon dioxide. 
     
     
         20 . The mouthpiece, filter or filter element according to  claim 1  wherein the mouthpiece, filter or filter element has ‘Ready Biodegradability’ level of biodegradability as measured according to OECD 301 B ‘Ready Biodegradability’ method (modified Sturm test). 
     
     
         21 . A multi-segment filter comprising a mouthpiece, filter or filter element according to  claim 1  and one or more discrete further segments. 
     
     
         22 . A smoking article (e.g., a cigarette, e.g., a tobacco heating product, e.g., a HNB product) comprising a mouthpiece, filter, filter element or multi-segment filter according to  claim 1  joined at one end to a wrapped tobacco rod (e.g., by conventional means, i.e., by a tipping paper). 
     
     
         23 . A method for making a mouthpiece, filter or filter element comprising the steps of:
 providing a longitudinally extending continuous core of paper or other biodegradable (e.g., non cellulose acetate containing) filtering material;   engaging and securing a first wrapper (e.g., plugwrap) around the peripheral surface of the core;   engaging and securing a second wrapper around the wrapped core, the first wrapper defining at least with the second wrapper a plurality of channels extending longitudinally of the core;   cutting the continuous core to form individual mouthpieces or filter elements, arranged so the cut ends form the upstream end of the mouthpiece, filter or filter element and the downstream end of the mouthpiece, filter or filter element.   
     
     
         24 . The method of making a mouthpiece, filter or filter element according to  claim 23  wherein the first wrapper is embossed to provide a profiled (e.g., corrugated) surface, such that it has longitudinally extending corrugations along regular sections of its length. 
     
     
         25 . A mouthpiece, filter or filter element obtained by the method of  claim 23 .