WO2024008580A1

WO2024008580A1 - Crimping roller with increased number of interruption gaps

Info

Publication number: WO2024008580A1
Application number: PCT/EP2023/068025
Authority: WO
Inventors: Rosa BONELLI; Alessandro Coppola
Original assignee: Philip Morris Products S.A.
Priority date: 2022-07-04
Filing date: 2023-06-30
Publication date: 2024-01-11

Abstract

The present invention relates to a method for producing a plug (33) forming part of an aerosol-generating article, the method comprising the steps of feeding a sheet along a longitudinal direction of the sheet to a set of crimping rollers, forming a crimped sheet (8) by crimping the sheet, wherein the crimped sheet comprises a plurality of corrugated regions and a plurality of interruption bands (26), wherein in the corrugated regions, the crimped sheet comprises a plurality of corrugations (16) extending in the longitudinal direction, wherein in the interruption bands, the crimped sheet is free of corrugations or comprises corrugations having a smaller corrugation amplitude compared to the corrugations in the corrugated regions, wherein the interruption bands and the corrugated regions are alternatingly arranged, wherein each interruption band of the plurality of interruption bands comprises a leading portion (27) and a trailing portion (28), wherein the leading portion is arranged at a different location with respect to the longitudinal direction than the trailing portion, gathering the crimped sheet to form a gathered sheet (31), and forming a plug from the gathered sheet, wherein in the crimped sheet, the distance between two adjacent interruption bands in the longitudinal direction is smaller than half of the length of the plug in the longitudinal direction. The invention further relates to a plug for forming part of an aerosol-generating article, a crimping roller and the use of interrupted circumferential ridges on a crimping roller.

Description

Crimping roller with increased number of interruption gaps

The present invention relates to a method for producing a plug forming part of an aerosolgenerating article, a plug for forming part of an aerosol-generating article, a crimping roller and a use of interrupted circumferential ridges on a crimping roller to form a plurality of interrupted crimp corrugations on a sheet prior to forming a plug out of the sheet.

WO2018189325A1 discloses a crimping roller having corrugations with inclined interruption bands. EP3214959B1 discloses a method and apparatus for manufacturing a crimping web.

There is a need for improving the strength, in particular the tensile strength, of crimped sheet material. There is also a need for preventing the release of substances, in particular loose particles of aerosol-generating substrates, out of a crimped and gathered sheet. There is also a need for controlling the resistance-to-draw value of a crimped sheet material.

According to a first aspect of the invention, there is provided a method for producing a plug forming part of an aerosol-generating article. A sheet is fed along a longitudinal direction of the sheet to a set of crimping rollers. The sheet is crimped to form a crimped sheet. The crimped sheet comprises a plurality of corrugated regions and a plurality of interruption bands. In the corrugated regions, the crimped sheet comprises a plurality of corrugations extending in the longitudinal direction. In the interruptions bands, the crimped sheet is free of corrugations or comprises corrugations having a smaller corrugation amplitude compared to the corrugations in the corrugations regions. The interruption bands and the corrugated regions are alternatingly arranged. Each interruption band of the plurality of interruption bands comprises a leading portion and a trailing portion. The leading portion is arranged at a different location with respect to the longitudinal direction than the trailing portion. The leading portion and the trailing portion may be arranged at opposite sides of the crimped sheet with respect to the width of the sheet. The crimped sheet is gathered to form a gathered sheet. A plug is formed out of the gathered sheet. In the crimped sheet, the distance between two adjacent interruption bands in the longitudinal direction is smaller than half of the length of the plug in the longitudinal direction.

The plug may extend predominantly in the longitudinal direction.

A crimped sheet may be formed, on which surface patterns having a specific distribution of corrugated regions and non-corrugated or less corrugated regions may be created to form a crimping pattern. The crimping pattern may allow to maintain good overall tensile strength of the sheet and may prevent fly outs.

The plurality of corrugations in the corrugated regions may extend in a direction that is inclined to the longitudinal direction.

The term sheet may refer to a laminar element having a width and length substantially greater than its thickness. The term corrugations may refer to a plurality of substantially parallel ridges. The corrugations may have a square wave profile, a sinusoidal wave profile, a triangular profile, a saw-tooth profile, or a combination thereof. The term crimped sheet may refer to a sheet having a plurality of corrugations. The term gathered may denote that a sheet is convoluted or otherwise compressed or constricted substantially transversely to the longitudinal direction.

Crimping may be different from embossing. Embossing may refer to forming indentations on a surface of an element by pressing an external object against the surface of the element to form the indentation. In crimping, a sheet material may be pushed against ridges or ridges may be pushed against a sheet material. The ridges may apply pressure to the sheet material, such that the sheet material may bend over the ridges. This may cause the sheet material to break open on the opposite side of the respective ridge.

The corrugation amplitude may refer to the height of the corrugation, in particular the distance the corrugation protrudes from the rest of the sheet. The corrugation amplitude may refer to the distance between the peak of the corrugation to the base of the corrugation.

The distance between two adjacent interruption bands may be defined as the distance from an edge of a first interruption band to an edge of a second interruption band, in particular adjacent to the first interruption.

The corrugated regions may define channels in the plug. The channels may extend in the longitudinal direction. The interruption bands may prevent fly out of loose pieces of aerosolgenerating substrate from the channels during the making of the plug or transport. Having interruption bands with a distance between two adjacent interruption bands smaller than half of the plug length may prevent fly out of pieces of the aerosol-generating substrate on both ends of the plug. Having interruption bands with a distance between two adjacent interruption bands smaller than half of the plug length may improve the shape of the plug and may result in a more even surface of the plug. The crimped material may be gathered easier and more evenly. It may also increase the strength, in particular the tensile strength, of the crimped material. It may improve the formation of air passages or air channels in the plug. It may result in a better resistance-to-draw value of the plug. It may provide a balance between improved channel formation in the crimped sheet and the plug as well as improved tensile strength of the crimped sheet and the plug.

A continuously crimped sheet, without any interruption bands, may have a relatively low tensile strength because the crimp corrugations weaken the sheet material. This may cause problems when the crimped sheet is transported from the crimping rollers to the wrapping or gathering tool. In the region of the interruption bands the sheet may be not crimped or less crimped, thus the material is less weakened, leading to a higher tensile strength compared to the crimped regions. However, the thickness of the sheet material in the regions of the interruption bands may be greater due to being not or less crimped. This may cause problems when the crimped sheet is gathered. For example, when the crimped sheet is gathered, the uncrimped or less crimped regions may obstruct the parallel alignment of the channels that are formed in the crimped material and may add randomness to the alignment of the channels. Such randomness may result in unpredictability of the fluid dynamics in the plug and thus undesired resistance-to-draw values. It may also complicate the insertion of a heating element into the plug. Spacing the interruption bands closer together may create a more even distribution between interruption bands and crimped regions. Thus, the tensile strength of the crimped sheet may be increased as well as less randomness in the alignment of channels may be caused when the crimped sheet is gathered. This may lead to a better resistance-to-draw value of the finished plug.

Having interruption bands comprising a leading portion and a trailing portion, wherein the leading portion may be arranged at a different location with respect to the longitudinal direction than the trailing portion may result in inclined interruption bands. Inclined interruption bands may improve the shape of the plug and may result in a more even surface of the plug. The interruption bands may be inclined with respect to the longitudinal direction. The interruption bands may be inclined with respect to a direction orthogonal to the longitudinal direction.

The leading portion and the trailing portion may be arranged adjacent to opposite edges of the crimped sheet with respect to the width of the crimped sheet. The leading portion may be arranged at a first side of the crimped sheet. The trailing portion may be arranged at a second side of the crimped sheet. The first side may be arranged on one end of the extension of the crimped sheet orthogonal to the longitudinal direction. The first side may be arranged on the other end of the extension of the crimped sheet orthogonal to the longitudinal direction.

Each interruption band may extend primarily along a main path, referred to as primary extension of the interruption band. A secondary extension of the interruption band may be the extension of the interruption band in the longitudinal direction. The direction of the primary extension may be different from the direction of the secondary extension. The corresponding main paths of adjacent interruption bands may be parallel to each other. The corresponding main paths of adjacent interruption bands may be offset by a distance in the longitudinal direction.

Each main path, also referred to as the main path, may start at a path start point adjacent to a first side. The main path may end at a path end point adjacent to a second side. The first side and the second side may be arranged on opposite sides with respect to the width of the crimped sheet. The direction of the main path may change along its extension from the path start point to the path end point. The main path may have a chevron shape. The main path may have a triangle shape. All main paths may be parallel to each other. All main paths may extend predominantly in the same direction. The longitudinal distance between two adjacent interruption bands may be smaller than one third of the length of the plug in the longitudinal direction. The longitudinal distance between two adjacent interruption bands may be smaller than one fourth or one fifth of the length of the plug in the longitudinal direction. Reducing the longitudinal distance between adjacent interruption bands may result in a better protection against fly out of the aerosolgenerating substrate, may result in a more even surface of the plug and may increase the strength, in particular the tensile strength, of the crimped material. It may also result in a better resistance-to-draw value of the plug. The crimped sheet may also be gathered easier and more evenly.

At least three, at least four, or at least five interruption bands may be formed in the sheet over a longitudinal distance equal to the length of the plug in the longitudinal direction.

The step of forming a plug from the gathered sheet may comprise the steps of forming a rod out of the gathered sheet and cutting the rod to form the plug. It may be more efficient to form a long rod first, and to subsequently cut the rod into multiple plugs. This may increase throughput.

Cutting the rod to form a plug may comprise two to five, preferably three to four cutting steps. The rod may be cut into two to sixteen, preferably four to eight plugs. The rod may be cut into a plurality of substantially uniform plugs. Forming multiple plugs out of one rod may increase production efficiency.

The plug may be a filter for an aerosol-generating article. The plug may be used to form or to contain an aerosol-generating substrate.

The crimped sheet may be cut into a predefined length prior to gathering the crimped sheet to form a gathered sheet. The corrugations may be formed on a continuous sheet to form a continuous crimped sheet. The continuous crimped sheet may be cut into a predefined length prior to gathering the sheet. Cutting the sheet into a predefined length may facilitate gathering the sheet.

The plurality of interruption bands may be uniformly spaced from each other. This may result in a better protection against fly out of the aerosol-generating substrate, may result in a more even surface of the rod and may increase the strength, in particular the tensile strength, of the crimped material. It may also result in a better resistance-to-draw value of the rod. The crimped sheet may also be gathered easier and more evenly.

An angle between the extension of the interruption bands in the crimped sheet and the longitudinal direction may be between 70 degrees and 90 degrees, in particular between 75 and 85 degrees, in particular about 84 degrees.

The interruption bands may be inclined with respect to the longitudinal direction. The inclination of an interruption band may vary along the extension of the interruption band. An interruption band may be inclined in two opposite directions with respect to the longitudinal direction. The sign of the value of the inclination of an interruption band may change along the extension of the interruption band. For example, the interruption bands may have a chevron shape, a diamond shape or a triangular shape. This means that the width of the interruption bands may change along the extension of the interruption bands. The interruption bands may be curved. The interruption bands may have the shape of a wave. The sign of the value of the inclination of an interruption band may change multiple times along the extension of the interruption band.

The leading portion of the interruption band may be in front of the trailing portion of the interruption band with respect to the longitudinal direction. The interruption band may comprise two or more leading portions. The interruption band may comprise two or more trailing portions.

The interruption bands may extend at an angle of more than 60 degrees with respect to the longitudinal direction. At least three interruption bands may intersect a straight line across the sheet orthogonal to the longitudinal direction.

The interruption bands may be parallel to each other. The channels formed by the corrugations in the crimped sheet may have substantially the same length.

The extension of an interruption band in the longitudinal direction may be between 2 millimeters and 5 millimeters, in particular between 3 millimeters and 4 millimeters, in particular about 3.5 millimeters. Such a value may be sufficient to interrupt the channels inside the crimped sheet. Such a value may be optimal to improve the resistance to draw value of the plug. Such a value may be optimal to improve the shape of the plug.

An interruption band width may be the extension of an interruption band in the longitudinal direction. The ratio of the longitudinal distance between two adjacent interruption bands to the interruption band width may be between 0.5 and 5, in particular between 1 and 3, in particular about 2. Such a value may be sufficient to interrupt the channels inside the crimped sheet. Such a value may be optimal to improve the resistance to draw value of the plug. Such a value may be optimal to improve the shape of the plug. The ratio of the longitudinal distance between two adjacent interruption bands to the interruption band width may be between 0.5 and 2, between 1 and 3, between 2 and 4 or between 3 and 5. The ratio of the longitudinal distance between two adjacent interruption bands to the interruption band width may be between 0.5 and 1 , between 1 and 2, between 2 and 3, between 3 and 4 or between 4 and 5.

The interruption band width may be constant within an interruption band. All interruption bands may have the same interruption band width. The interruption band width may vary within an interruption band. The interruption band width may vary between different interruption bands. All interruption bands may have the same shape. The distance between two adjacent interruption bands in the longitudinal direction may be greater than the extension of an interruption band in the longitudinal direction.

The distance between two adjacent interruption bands in the longitudinal direction may be smaller than 6 millimeters. The distance between two adjacent interruption bands in the longitudinal direction may be smaller than 6 millimeters and smaller than half of the length of the plug in the longitudinal direction.

A crimped sheet width may be the extension of the crimped sheet orthogonal to the longitudinal direction. The interruption band may be discontinuous across the crimped sheet width. The interruption bands may be interrupted by interruption band gaps. Interruption band gaps of two adjacent interruption bands may be arranged at an offset with respect to a direction orthogonal to the longitudinal direction. This may ensure that interrupted channels are formed in the crimped sheet. The plurality of interruption bands may be discontinuous across the crimped sheet width.

The length of the plug in the longitudinal direction may be between 5 millimeters and 20 millimeters, in particular between 7 millimeters and 17 millimeters, in particular about 12 millimeters. A plug with such a length may be used in a cigarette. A plug with such a length may be used in an aerosol-generating article for an electronic smoking device.

A sheet width may be the extension of the sheet in a direction orthogonal to the longitudinal direction. The sheet width may be 5 centimeters to 20 centimeters, in particular about 11 centimeters. Such a sheet width may result in a plug of a desired diameter, in particular to be used in an aerosol-generating article.

According to a second aspect of the invention, there is provided a plug for forming part of an aerosol-generating article. The plug may be formed with the method according to the first aspect of the invention. The plug extends in a longitudinal direction. The plug comprises a gathered sheet. The gathered sheet may comprise a plurality of corrugation lines extending in the longitudinal direction. At least one corrugation line of the plurality of corrugation lines is interrupted at least three times in the longitudinal direction by interruption bands.

Such a configuration of interrupted corrugation lines may result in a better protection against fly out of an aerosol-generating substrate in the plug, may result in a more even surface of the plug and may increase the strength, in particular the tensile strength, of the plug. It may also result in a better resistance-to-draw value of the plug. The sheet may also be gathered easier and more evenly.

At least one corrugation line of the plurality of corrugations lines may be interrupted at least four times in the longitudinal direction by interruption bands.

All corrugations lines of the plurality of corrugations lines may be interrupted at least twice or at least three times in the longitudinal direction by interruption bands. The interruption bands may be flat sections or sections with corrugations having a smaller corrugation amplitude compared to the rest of the corrugation line.

A corrugation line may be a substantially straight corrugation or ridge. An interruption band may be a region where the corrugation line has a lower corrugation amplitude compared to the rest of the corrugation line. An interruption band may be a non-corrugated region.

The interruption bands may be inclined with respect to the longitudinal direction. An angle between the extension of the interruption bands in the gathered sheet and the longitudinal direction may be between 70 degrees and 90 degrees, in particular between 75 and 85 degrees, in particular about 84 degrees. The angle may refer to the angle on the crimped sheet before the sheet is gathered. The interruption bands may be inclined with respect to a direction orthogonal to the longitudinal direction.

Each interruption band may comprise a leading portion and a trailing portion. The leading portion may be arranged at a different location than the trailing portion with respect to the longitudinal direction. Each interruption band may have two or more trailing portions. Each interruption band may have two or more leading portions.

The leading portion and the trailing portion may be arranged adjacent to opposite edges of the gathered sheet with respect to the width of the gathered sheet. The leading portion and the trailing portion may be arranged adjacent to opposite edges of the crimped sheet with respect to the width of the crimped sheet before the sheet is gathered. The leading portion may be arranged at a first side of the crimped sheet. The trailing portion may be arranged at a second side of the crimped sheet. The first side may be arranged on one end of the extension of the crimped sheet orthogonal to the longitudinal direction. The first side may be arranged on the other end of the extension of the crimped sheet orthogonal to the longitudinal direction.

Each main path, also referred to as the main path, may start at a path start point adjacent to a first side. The main path may end at a path end point adjacent to a second side. The first side and the second side may be arranged on opposite sides with respect to the width of the gathered sheet or crimped sheet. The direction of the main path may change along its extension from the path start point to the path end point. The main path may have a chevron shape. The main path may have a triangle shape. All main paths may be parallel to each other. All main paths may extend predominantly in the same direction. The distance between two adjacent interruption bands in the longitudinal direction may be greater than the extension of an interruption band in the longitudinal direction.

The ratio of the longitudinal distance between two adjacent interruption bands to the interruption band width may be between 0.5 and 5, in particular between 1 and 3, in particular about 2. The ratio of the longitudinal distance between two adjacent interruption bands to the interruption band width may be between 0.5 and 2, between 1 and 3, between 2 and 4 or between 3 and 5. The ratio of the longitudinal distance between two adjacent interruption bands to the interruption band width may be between 0.5 and 1 , between 1 and 2, between 2 and 3, between 3 and 4 or between 4 and 5.

The extension of an interruption band in the longitudinal direction may be between 2 millimeters and 5 millimeters, in particular between 3 millimeters and 4 millimeters, in particular about 3.5 millimeters.

According to a third aspect of the invention, there is provided a crimping roller, adapted to rotate around a rotation axis that extends in an axial direction. The crimping roller comprises a plurality of circumferential ridges. Each circumferential ridge has a first ridge amplitude, and a plurality of interruption gaps. In the interruption gaps, the plurality of circumferential ridges have a second ridge amplitude. The second ridge amplitude is smaller than the first ridge amplitude. An interruption gap width is the extension of an interruption gap in a circumferential direction of the crimping roller. A circumferential distance between two interruption gaps is smaller than the interruption gap width.

An interruption gap may extend across multiple circumferential ridges. Each of the plurality of interruption gaps may extend across multiple circumferential ridges.

The circumferential ridges may form a ridge-and-trough pattern on a circumferential surface of the crimping roller. On the developed circumferential surface of the crimping roller, the circumferential ridges may extend in a direction orthogonal to the axial direction.

The circumferential distance between two interruption gaps may be the circumferential distance between an edge of a first interruption gap to an edge of a second interruption gap, in particular adjacent to the first interruption gap.

Each interruption gap may extend primarily along a main path, referred to as primary extension of the interruption gap. A secondary extension of the interruption gap may be the extension of the interruption gap in the circumferential direction. The direction of the primary extension may be different from the direction of the secondary extension. The corresponding main paths of adjacent interruption gaps may be parallel to each other. The corresponding main paths of adjacent interruption gaps may be offset by a distance in the longitudinal direction.

Each main path, also referred to as the main path, may start at a path start point adjacent to a first side of the crimping roller. The main path may end at a path end point adjacent to a second side of the crimping roller. The first side and the second side may be arranged on opposite sides with respect to the axial direction of the crimping roller. The direction of the main path may change along its extension from the path start point to the path end point. The main path may have a chevron shape. The main path may have a triangle shape.

The distance between two adjacent interruption gaps in the circumferential direction may be greater than the extension of an interruption gaps in the circumferential direction.

The distance between two adjacent interruption gaps in the circumferential direction may be smaller than 6 millimeters.

The extension of an interruption gap in the circumferential direction may be between 2 millimeters and 5 millimeters, in particular between 3 millimeters and 4 millimeters, in particular about 3.5 millimeters.

The ratio of the circumferential distance between two adjacent interruption gaps to the interruption gap width may be between 0.5 and 5, in particular between 1 and 3, in particular about 2. The ratio of the circumferential distance between two adjacent interruption gaps to the interruption gap width may be between 0.5 and 2, between 1 and 3, between 2 and 4 or between 3 and 5. The ratio of the circumferential distance between two adjacent interruption gaps to the interruption gap width may be between 0.5 and 1 , between 1 and 2, between 2 and 3, between 3 and 4 or between 4 and 5.

According to a fourth aspect of the invention, there is provided a crimping roller, adapted to rotate around a rotation axis that extends in an axial direction. The crimping roller comprises a plurality of circumferential ridges, each ridge having a first ridge amplitude, and a plurality of interruption gaps. In the interruption gaps, the plurality of circumferential ridges have a second ridge amplitude. The second ridge amplitude is smaller than the first ridge amplitude. A circumferential distance between two interruption gaps is smaller than 6 millimeters.

The circumferential ridges may form a ridge-and-trough pattern on a circumferential surface of the crimping roller. On a developed circumferential surface of the crimping roller, the circumferential ridges may extend in a direction orthogonal to the axial direction. On the developed circumferential surface of the crimping roller, the circumferential ridges may be inclined with respect to a direction orthogonal to the axial direction.

On the developed circumferential surface of the crimping roller, the interruption gaps may be inclined with respect to a direction orthogonal to the axial direction. On the developed circumferential surface, each interruption gap may extend primarily along a main path, referred to as primary extension of the interruption gap. A secondary extension of the interruption gap may be the extension of the interruption gap in the circumferential direction. The direction of the primary extension may be different from the direction of the secondary extension. The corresponding main paths of adjacent interruption gaps may be parallel to each other. The corresponding main paths of adjacent interruption gaps may be offset by a distance in the longitudinal direction.

Each main path, also referred to as the main path, may start at a path start point adjacent to a first side of the developed circumferential surface of the crimping roller. The main path may end at a path end point adjacent to a second side of the developed circumferential surface of the crimping roller. The first side and the second side may be arranged on opposite sides with respect to the axial direction of the crimping roller. The direction of the main path may change along its extension from the path start point to the path end point. The main path may have a chevron shape. The main path may have a triangle shape. All main paths may be parallel to each other. All main paths may extend predominantly in the same direction.

The distance between two adjacent interruption gaps in the circumferential direction may be greater than the extension of an interruption gap in the circumferential direction.

According to a fifth aspect of the invention, there is provided a crimping roller, adapted to rotate around a rotation axis that extends in an axial direction. The crimping roller comprises a plurality of circumferential ridges, each ridge having a first ridge amplitude, and a plurality of interruption gaps. In the interruption gaps, the plurality of circumferential ridges have a second ridge amplitude. The second ridge amplitude is smaller than the first ridge amplitude. The interruption gaps extend at an angle of less than 30 degrees, in particular between 1 degree and 30 degrees, with respect to the axial direction. At least three interruption gaps intersect a straight line along the axial direction on a circumferential surface of the crimping roller.

The angle of the interruption gaps with respect to the axial direction may be measured on the developed circumferential surface of the crimping roller.

At least four interruption gaps may intersect a straight line along the axial direction on a circumferential surface of the crimping roller.

Each of the plurality of interruption gaps may extend across the circumferential surface of the crimping roller. Each of the plurality of interruption gaps may extend across the whole circumferential surface of the crimping roller in the axial direction.

Each of the plurality of interruption gaps may be inclined with respect to the axial direction. On the developed circumferential surface of the crimping roller, each of the plurality of interruption gaps may be inclined with respect to the axial direction. Each of the plurality of interruption gaps may be inclined with respect to the axial direction at an angle of 1 degree to 20 degrees, in particular 5 degrees to 15 degrees, in particular about 6 degrees.

An angle between an interruption gap and the axial direction may be between 1 degree and 20 degrees, in particular between 5 degrees and 15 degrees, in particular about 6 degrees.

The angle may be measured on the developed circumferential surface of the crimping roller.

The inclination of an interruption gap with respect to the axial direction may vary along the extension of the interruption gap. The inclination of an interruption gap with respect to the axial direction may change direction along the extension of the interruption gap. For example, the interruption gaps may be chevron shaped. The interruption gaps may be diamond or triangular shaped. This means that the width of the interruption gaps may change along the extension of the interruption gaps. The interruption gaps may be curved. The interruption gaps may have the shape of a wave.

Each main path, also referred to as the main path, may start at a path start point adjacent to a first side of the crimping roller. The main path may end at a path end point adjacent to a second side of the crimping roller. The first side and the second side may be arranged on opposite sides with respect to the axial direction of the crimping roller. The direction of the main path may change along its extension from the path start point to the path end point. The main path may have a chevron shape. The main path may have a triangle shape. All main paths may be parallel to each other. All main paths may extend predominantly in the same direction.

The circumferential ridges may form a ridge-and-trough pattern on a circumferential surface of the crimping roller.

The ridges may extend substantially orthogonal to the rotation axis of the crimping roller. On the developed circumferential surface of the crimping roller, the circumferential ridges may extend in a direction orthogonal to the axial direction. On the developed circumferential surface of the crimping roller, the circumferential ridges may be inclined with respect to a direction orthogonal to the axial direction.

The crimping roller may comprise 45 interruption gaps to 65 interruption gaps, in particular 50 interruption gaps to 60 interruption gaps, in particular about 54 interruption gaps.

The interruption bands may be substantially equidistantly spaced around the circumferential surface of the crimping roller. The interruption gaps may be parallel to each other.

The difference between the first ridge amplitude and the second ridge amplitude may be between 0.3 millimeters and 1 millimeter, in particular about 0.3 millimeters. The first ridge amplitude may between 0.5 millimeters and 1.5 millimeters, in particular about 1 millimeter. The second ridge amplitude may be between 0 millimeters to 1 .2 millimeters, in particular about 0.7 millimeters.

An apparatus for crimping a sheet may comprise a first crimping roller according to the third, fourth or fifth aspect of the invention and a second crimping roller adapted to rotate around a second rotation axis. The second crimping roller may comprise a plurality of circumferential ridges.

The first crimping roller and the second crimping roller may rotate or may be configured to rotate in different rotations. The rotation axis of the first crimping roller and the second rotation axis may be parallel to each other.

The circumferential ridges of the second crimping roller may extend continuously around the second crimping roller. The second crimping roller may be free of interruption gaps.

The circumferential ridges of the first crimping roller may form a ridge-and-trough pattern. The circumferential ridges of the second crimping roller may form a ridge-and-trough pattern. The ridge-and-trough pattern of the second crimping roller may be offset in the axial direction from the ridge-and-trough pattern of the first crimping roller, such that ridges of the first crimping roller may be aligned with troughs of second crimping roller and vice versa.

The circumferential ridges of the first crimping roller and circumferential ridges of the second crimping roller may overlap each other by 0.1 millimeters to 0.5 millimeters, in particular about 0.2 millimeters, with respect to a direction orthogonal to the rotation axis of the first crimping roller. Thus, a difference of 0.2 millimeters, preferably 0.3 millimeters, between the first ridge amplitude and the second ridge amplitude may be sufficient to form no corrugations on the sheet in the region of the interruption gaps. The difference between the first ridge amplitude and the second ridge amplitude may be selected based on the overlap of the circumferential ridges of the first crimping roller and the circumferential ridges of the second crimping roller.

A sheet may be transferred through a gap between the first crimping roller and the second crimping roller. The sheet may be bend over the circumferential ridges of the first crimping roller and the circumferential ridges of the second crimping roller. This may cause the sheet to crack open on the opposite side of the respective circumferential ridge to form corrugations. In a region of an interruption gap, the circumferential ridges of the first crimping roller may not overlap with the circumferential ridges of the second crimping roller, such that the sheet may not be bend over in this region. Thus, the sheet may not crack open and may remain free of corrugations in this region.

An aerosol-generating article production machine may comprise a crimping roller according to the third, fourth or fifth aspect of the invention or and apparatus for crimping a sheet according to the fifth aspect of the invention. According to a sixth aspect of the invention, there is provided a use of interrupted circumferential ridges on a crimping roller to form a plurality of interrupted crimp corrugations on a sheet prior to forming a plug out of the sheet. The crimp corrugations extend in a longitudinal direction of the sheet. The distance between two interruptions in a crimp corrugation in the longitudinal direction is smaller than half of the length of the rod in the longitudinal direction.

The plug may be cut from a rod that is formed from the sheet with the plurality of interrupted crimp corrugations.

The distance between two interruptions in a crimp corrugation in the longitudinal direction may be smaller than one third of the length of the rod in the longitudinal direction.

Interruptions of adjacent crimp corrugations may form interruption bands. The interruption bands may extend over the entire width of the sheet.

The interruption bands may be inclined with respect to the longitudinal direction. An angle between the extensions of the interruption bands and the longitudinal direction may be between 70 degrees and 90 degrees, in particular between 75 and 85 degrees, in particular about 84 degrees. The interruption bands may be inclined with respect to a direction orthogonal to the longitudinal direction.

Each main path, also referred to as the main path, may start at a path start point adjacent to a first side. The main path may end at a path end point adjacent to a second side. The first side and the second side may be arranged on opposite sides with respect to the width of the crimped sheet. The direction of the main path may change along its extension from the path start point to the path end point. The main path may have a chevron shape. The main path may have a triangle shape. All main paths may be parallel to each other. All main paths may extend predominantly in the same direction.

The distance between two adjacent interruption bands in the longitudinal direction may be greater than the extension of an interruption band in the longitudinal direction.

The distance between two adjacent interruption bands in the circumferential direction may be smaller than 6 millimeters. The distance between two adjacent interruption bands in the longitudinal direction may be smaller than 6 millimeters and smaller than half of the length of the plug in the longitudinal direction. The extension of an interruption band in the circumferential direction may be between 2 millimeters and 5 millimeters, in particular between 3 millimeters and 4 millimeters, in particular about 3.5 millimeters.

The method of the first aspect of the invention may be performed with a crimping roller according to the third, fourth or fifth aspect of the invention. The method of the first aspect of the invention may be used to manufacture a plug according to the second aspect of the invention. The plug according to the second aspect of the invention may be manufactured with the crimping roller according to the third, fourth or fifth aspect of the invention or using method steps of the method according to the first aspect of the invention. The crimping roller according to the third, fourth or fifth aspect of the invention may be used using method steps according to the method of the first aspect of the invention. The crimping roller according to the third, fourth or fifth aspect of the invention may be used to manufacture a plug according to the second aspect of the invention. The use of interrupted circumferential ridges on a crimping roller according to the sixth aspect of the invention may be performed with a crimping roller according to the third, fourth of fifth aspect of the invention or using method steps from the method according to the first aspect of the invention.

The invention is defined in the claims. However, below there is provided a non- exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example Ex1 : Method for producing a plug forming part of an aerosol-generating article, the method comprising the steps of feeding a sheet along a longitudinal direction of the sheet to a set of crimping rollers, forming a crimped sheet by crimping the sheet, wherein the crimped sheet comprises a plurality of corrugated regions and a plurality of interruption bands, wherein in the corrugated regions, the crimped sheet comprises a plurality of corrugations extending in the longitudinal direction, wherein in the interruption bands, the crimped sheet is free of corrugations or comprises corrugations having a smaller corrugation amplitude compared to the corrugations in the corrugated regions, wherein the interruption bands and the corrugated regions are alternatingly arranged, wherein each interruption band of the plurality of interruption bands comprises a leading portion and a trailing portion, wherein the leading portion is arranged at a different location with respect to the longitudinal direction than the trailing portion, gathering the crimped sheet to form a gathered sheet, and forming a plug from the gathered sheet, wherein in the crimped sheet, the distance between two adjacent interruption bands in the longitudinal direction is smaller than half of the length of the plug in the longitudinal direction.

Example Ex2: Method for producing a plug forming part of an aerosol-generating article according to example Ex1 , wherein the longitudinal distance between two adjacent interruption bands is smaller than one third of the length of the plug in the longitudinal direction.

Example Ex3: Method for producing a plug forming part of an aerosol-generating article according to example Ex1 , wherein the longitudinal distance between two adjacent interruption bands is smaller than one fourth or one fifth of the length of the plug in the longitudinal direction.

Example Ex4: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein at least three, at least four, or at least five interruption bands are formed in the sheet over a longitudinal distance equal to the length of the plug in the longitudinal direction.

Example Ex5: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the step of forming a plug from the gathered sheet comprises the steps of forming a rod out of the gathered sheet and cutting the rod to form the plug.

Example Ex6: Method for producing a plug forming part of an aerosol-generating article according to example Ex5, wherein cutting the rod to form a plug comprises two to five, preferably three to four cuts, in particular cutting steps.

Example Ex7: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the rod is cut into two to sixteen, preferably four to eight plugs.

Example Ex8: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the rod is cut into a plurality of substantially uniform plugs.

Example Ex9: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the crimped sheet is cut into a predefined length prior to gathering the crimped sheet to form a gathered sheet.

Example Ex10: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the plurality of interruption bands are uniformly spaced from each other.

Example Ex11 : Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein an angle between the extension of the interruption bands in the crimped sheet and the longitudinal direction is between 70 degrees and 90 degrees, in particular between 75 and 85 degrees, in particular about 84 degrees.

Example Ex12: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands are inclined with respect to the longitudinal direction, wherein the inclination of an interruption band varies along the extension of the interruption band.

Example Ex13: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands are inclined with respect to the longitudinal direction, wherein an interruption band is inclined in two opposite directions with respect to the longitudinal direction.

Example Ex14: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands are chevron shaped.

Example Ex15: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands are diamond shaped.

Example Ex16: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands are triangular shaped.

Example Ex17: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands are curved.

Example Ex18: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands have the shape of a wave.

Example Ex19: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the sign of the value of the inclination of an interruption band may change multiple times, in particular twice, three times or four times, along the extension of the interruption band.

Example Ex20: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the leading portion is in front of the trailing portion with respect to the longitudinal direction.

Example Ex21 : Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands extend at an angle of more than 60 degrees with respect to the longitudinal direction, wherein at least three interruption bands intersect a straight line across the sheet orthogonal to the longitudinal direction. Example Ex22: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the interruption bands are parallel to each other.

Example Ex23: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the extension of an interruption band in the longitudinal direction is between 2 millimeters and 5 millimeters, in particular between 3 millimeters and 4 millimeters, in particular about 3.5 millimeters.

Example Ex24: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein an interruption band width is the extension of an interruption band in the longitudinal direction, wherein the ratio of the longitudinal distance between two adjacent interruption bands to the interruption band width is between 0.5 and 5, in particular between 1 and 3, in particular about 2.

Example Ex25: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein an interruption band width is the extension of an interruption band in the longitudinal direction, wherein the interruption band width is constant within an interruption band.

Example Ex26: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein a crimped sheet width is the extension of the crimped sheet orthogonal to the longitudinal direction, wherein an interruption band is discontinuous across the crimped sheet width.

Example Ex27: Method for producing a plug forming part of an aerosol-generating article according to example Ex26, wherein the plurality of interruption bands are discontinuous across the crimped sheet width.

Example Ex28: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein the length of the plug in the longitudinal direction is between 5 millimeters and 20 millimeters, in particular between 7 millimeters and 17 millimeters, in particular about 12 millimeters.

Example Ex29: Method for producing a plug forming part of an aerosol-generating article according to any of the previous examples, wherein a sheet width is the extension of the sheet in a direction orthogonal to the longitudinal direction, wherein the sheet width is 5 centimeters to 20 centimeters, in particular about 11 centimeters.

Example Ex30: A plug, for example a plug for forming part of an aerosol-generating article, wherein the plug is in particular formed according to any of the previous examples, wherein the plug extends in a longitudinal direction, wherein the plug comprises a gathered sheet, wherein the gathered sheet comprises a plurality of corrugation lines extending in the longitudinal direction, and wherein at least one corrugation line of the plurality of corrugation lines is interrupted at least three times in the longitudinal direction by interruption bands. Example Ex31 : A plug, for example a plug for forming part of an aerosol-generating article, according to example Ex30, wherein at least one corrugation line of the plurality of corrugation lines is interrupted at least four times in the longitudinal direction by interruption bands.

Example Ex32: A plug, for example a plug for forming part of an aerosol-generating article, according to example Ex30 or Ex31 , wherein all corrugations lines of the plurality of corrugation lines are interrupted at least twice or at least three times in the longitudinal direction by interruption bands.

Example Ex33: A plug, for example a plug for forming part of an aerosol-generating article, according to any of examples Ex30 to Ex32, wherein the interruption bands are flat sections or sections with corrugations having a smaller corrugation amplitude compared to the rest of the corrugation lines.

Example Ex34: A plug, for example a plug for forming part of an aerosol-generating article, according to any of examples Ex30 to Ex33, wherein the interruption bands may be inclined with respect to the longitudinal direction.

Example Ex35: A plug, for example a plug for forming part of an aerosol-generating article, according to any of examples Ex30 to Ex34, wherein each interruption band comprises a leading portion and a trailing portion, wherein the leading portion is arranged at a different location with respect to the longitudinal direction than the trailing portion.

Example Ex36: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, comprising a plurality of circumferential ridges, each circumferential ridge having a first ridge amplitude, and a plurality of interruption gaps, wherein in the interruption gaps, the plurality of circumferential ridges have a second ridge amplitude, wherein the second ridge amplitude is smaller than the first ridge amplitude, wherein an interruption gap width is the extension of an interruption gap in a circumferential direction of the crimping roller, wherein a circumferential distance between two interruption gaps is smaller than the interruption gap width.

Example Ex37: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, comprising a plurality of circumferential ridges, each circumferential ridge having a first ridge amplitude, and a plurality of interruption gaps, wherein in the interruption gaps, the plurality of circumferential ridges have a second ridge amplitude, wherein the second ridge amplitude is smaller than the first ridge amplitude, wherein a circumferential distance between two interruption gaps is smaller than 6 millimeters.

Example Ex38: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, comprising a plurality of circumferential ridges, each circumferential ridge having a first ridge amplitude, and a plurality of interruption gaps, wherein in the interruption gaps, the plurality of circumferential ridges have a second ridge amplitude, wherein the second ridge amplitude is smaller than the first ridge amplitude, wherein the interruption gaps extend at an angle of less than 30 degrees, in particular between 1 degree and 30 degrees, with respect to the axial direction, wherein at least three interruption gaps intersect a straight line along the axial direction on a circumferential surface of the crimping roller.

Example Ex39: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex38, wherein at least four interruption gaps intersect a straight line along the axial direction on a circumferential surface of the crimping roller.

Example Ex40: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex39, wherein an interruption gap extends across multiple circumferential ridges.

Example Ex41 : A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex40, wherein each of the plurality of interruption gaps extends across multiple circumferential ridges.

Example Ex42: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex41 , wherein each of the plurality of interruption gaps is inclined with respect to the axial direction.

Example Ex43: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex42, wherein an angle between an interruption gap and the axial direction is between 1 degree and 20 degrees, in particular between 5 degrees and 15 degrees, in particular about 6 degrees.

Example Ex44: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to example Ex42 or Ex43, wherein the inclination of an interruption gap with respect to the axial direction varies along the extension of the interruption gap.

Example Ex45: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex42 to Ex44, wherein the inclination of an interruption gap with respect to the axial direction changes direction along the extension of the interruption gap.

Example Ex46: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex45, wherein the interruption gaps are chevron shaped.

Example Ex47: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex46, wherein the interruption gaps are diamond shaped. Example Ex48: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex47, wherein the interruption gaps are triangular shaped.

Example Ex49: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex48, wherein the interruption gaps are curved.

Example Ex50: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex49, wherein the interruption gaps have the shape of a wave.

Example Ex51 : A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex50, wherein the crimping roller comprises 45 interruption gaps to 65 interruption gaps, in particular 50 interruption gaps to 60 interruption gaps, in particular about 54 interruption gaps.

Example Ex52: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex51 , wherein the interruption gaps are substantially equidistantly spaced around the circumferential surface of the crimping roller.

Example Ex53: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex52, wherein interruption gaps are parallel to each other.

Example Ex54: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex53, wherein the difference between the first ridge amplitude and the second ridge amplitude is between 0.3 millimeters and 1 millimeter, in particular about 0.3 millimeters.

Example Ex55: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex54, wherein the first ridge amplitude is between 0.5 millimeters and 1.5 millimeters, in particular about 1 millimeter.

Example Ex56: A crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, according to any of examples Ex36 to Ex55, wherein the ridges extend substantially orthogonal to the rotation axis of the crimping roller.

Example Ex57: An apparatus, for example for crimping a sheet, comprising a first crimping roller according to any of examples Ex36 to Ex56 and a second crimping roller adapted to rotate around a second rotation axis, wherein the second crimping roller comprises a plurality of circumferential ridges.

Example Ex58: An apparatus, for example for crimping a sheet, according to example

Ex57, wherein the first crimping roller and the second crimping roller rotate in different directions. Example Ex59: An apparatus, for example for crimping a sheet, according to example Ex57 or Ex58, wherein the rotation axis of the first crimping roller and the second rotation axis are parallel to each other.

Example Ex60: An apparatus, for example for crimping a sheet, according to any of examples Ex57 or Ex59, wherein the circumferential ridges of the second crimping roller extend continuously around the second crimping roller.

Example Ex61 : An apparatus, for example for crimping a sheet, according to any of examples Ex57 or Ex60, wherein the circumferential ridges form a ridge-and-trough pattern, and the ridge-and-trough pattern of the second crimping roller is offset in the axial direction from the ridge-and-trough pattern of the first crimping roller, such that ridges of the first crimping roller are aligned with the troughs of second crimping roller and vice versa.

Example Ex62: An apparatus, for example for crimping a sheet, according to any of examples Ex57 or Ex61 , wherein ridges of the first crimping roller and ridges of the second crimping roller overlap each other by 0.1 millimeters to 0.5 millimeters, in particular about 0.2 millimeters, with respect to a direction orthogonal to the rotation axis of the first crimping roller.

Example Ex63: A machine, for example an aerosol-generating article production machine, comprising a crimping roller according to any one of examples Ex36 to Ex56 or an apparatus for crimping a sheet according to any of examples Ex57 to Ex62.

Example Ex64: Use of interrupted circumferential ridges on a crimping roller to form a plurality of interrupted crimp corrugations on a sheet prior to forming a plug out of the sheet, wherein the crimp corrugations extend in a longitudinal direction of the sheet, wherein the distance between two interruptions in a crimp corrugation in the longitudinal direction is smaller than half of the length of the plug in the longitudinal direction.

Example Ex65: Use of interrupted circumferential ridges on a crimping roller according to example Ex64, wherein the plug is cut from a rod that is formed from the sheet with the plurality of interrupted crimp corrugations.

Example Ex66: Use of interrupted circumferential ridges on a crimping roller according to example Ex64 or Ex65, wherein the distance between two interruptions in a crimp corrugation in the longitudinal direction is smaller than one third of the length of the rod in the longitudinal direction.

Example Ex67: Use of interrupted circumferential ridges on a crimping roller according to any of examples Ex64 to Ex66, wherein interruptions of adjacent crimp corrugations form interruption bands, wherein the interruption bands are inclined with respect to the longitudinal direction.

The examples will now be further described with reference to the figures.

Fig. 1 shows a front view of a production machine according to an embodiment of the invention. Fig. 2 shows a perspective view of a set of crimping rollers according to an embodiment of the invention.

Fig. 3 shows a top view of a crimping roller according to an embodiment of the invention.

Fig. 4 shows a cross-sectional view of the crimping rollers of Fig. 2.

Fig. 5 shows a schematic overview of how a plug for an aerosol-generating article is produced according to an embodiment of the invention.

A production machine 1 according to an embodiment of the invention is shown in Fig. 1. The production machine 1 comprises a bobbin 2 with sheet 3. The sheet 3 is unwound from the bobbin 2 and transferred to a crimping apparatus 4. The crimping apparatus 4 comprises a set of crimping rollers 5. The set of crimping rollers 5 comprises a first crimping roller 6 and a second crimping roller 7. The crimping rollers 6, 7 are configured to form a crimped sheet 8 out of the sheet 3. The production machine 1 further comprises a gathering tool 9 to gather the crimped sheet 8.

Fig. 2 shows the set of crimping rollers 5 of the production machine 1 of Fig. 1 . The first crimping roller 6 rotates around a rotation axis 10. The second crimping roller 7 rotates around a second rotation axis 11. The rotation axes 10, 11 are parallel to each other and extend in an axial direction 200. The first crimping roller 6 and the second crimping roller 7 rotate in opposite directions. The first crimping roller 6 has a plurality of circumferential ridges 12 formed on its circumferential surface 13. The second crimping roller 7 also has a plurality of circumferential ridges 14 formed on its circumferential surface 15. The sheet 3 is transferred through the set of crimping rollers 5 along a longitudinal direction 100 of the sheet 3 to form a crimped sheet 8. The longitudinal direction 100 of the sheet 3 is orthogonal to the axial direction 200. The crimped sheet 8 comprises a plurality of corrugations 16 extending in the longitudinal direction 100 of the crimped sheet 8. The crimped sheet width 17 is the extension of the crimped sheet 8 in a direction orthogonal to the longitudinal direction 100.

The first crimping roller 6 is shown in greater detail in Fig. 3. The circumferential ridges

12 (not shown in Fig. 3) form a ridge-and-trough pattern 18 on the circumferential surface 13 of the first crimping roller 6. The ridge-and-trough pattern 18 and thus the circumferential ridges

13 are interrupted by interruption gaps 19. The interruption gaps 19 extend across the circumferential surface 13 of the first crimping roller 6. The interruption gaps 19 extend at an angle 20 with respect to the rotation axis 10 extending in the axial direction 200. The second crimping roller 7 also comprises a ridge-and-trough pattern 18, but is free of interruption gaps 19.

Fig. 4 shows a close view of the set of crimping rollers 5, in particular the circumferential ridges 12 of the first crimping roller 6 and the circumferential ridges 14 of the second crimping roller 7. The ridge-and-trough pattern 18 of the first crimping roller 6 is axially offset to the ridge-and-trough pattern 18 of the second crimping roller 7, such that the circumferential ridges 12 of the first crimping roller 6 are aligned with the troughs 21 of the second crimping roller 7 and vice versa.

The first crimping roller 6 and the second crimping roller 7 are arranged close to each other, such that there is an overlap 22 between the circumferential ridges 12 of the first crimping roller 6 and the circumferential ridges 14 of the second crimping roller 7. The circumferential ridges 12 have a first ridge amplitude 23. The first ridge amplitude 23 is the distance in a direction orthogonal to the axial direction 200 from the peak of the circumferential ridge 23 to an adjacent trough 21. In the interruption gaps 19, the circumferential ridges 12 have a second ridge amplitude 24, which is smaller than the first ridge amplitude 23. Fig. 4 also shows the axial distance 25 between two interruption gaps 19.

A crimped sheet 8 according to an embodiment of the invention is shown in Fig. 5. The crimped sheet 8 comprises a plurality of corrugations 16 extending in the longitudinal direction 100. The corrugations 16 are interrupted by interruption bands 26. In the region of the interruption bands 26, crimped sheet 8 is free of corrugations 16. The interruption bands 26 are inclined with respect to the longitudinal direction 100. Each interruption band 26 has a leading portion 27 and a trailing portion 28. The leading portion 27 and the trailing portion 28 are arranged at different locations with respect to the longitudinal direction 100. Each interruption band 26 has an interruption band width 29, which is the extension of the interruption band 26 in the longitudinal direction 100. The interruption bands 26 are spaced apart from each other in the longitudinal direction 100 by a constant distance 30.

The crimped sheet 8 is gathered to form a gathered sheet 31 , in particular a rod 32. The rod 32 is cut into multiple parts to form plugs 33 having a plug length 34. The distance 30 in the longitudinal direction 100 between two adjacent interruption bands 26 is smaller than half of the plug length 34, in particular smaller than one third of the plug length 34. The plugs 33 can be used in an aerosol-generating article.

Claims

1. Method for producing a plug for forming part of an aerosol-generating article, the method comprising the steps of:

- feeding a sheet along a longitudinal direction of the sheet to a set of crimping rollers,

- forming a crimped sheet by crimping the sheet, wherein the crimped sheet comprises a plurality of corrugated regions and a plurality of interruption bands, wherein in the corrugated regions, the crimped sheet comprises a plurality of corrugations extending in the longitudinal direction, wherein in the interruption bands, the crimped sheet is free of corrugations or comprises corrugations having a smaller corrugation amplitude compared to the corrugations in the corrugated regions, wherein the interruption bands and the corrugated regions are alternatingly arranged, wherein each interruption band of the plurality of interruption bands comprises a leading portion and a trailing portion, wherein the leading portion and the trailing portion are arranged on opposite sides of the crimped sheet with respect to the width of the crimped sheet, wherein the width of the crimped sheet is the extension of the crimped sheet orthogonal to the longitudinal direction, wherein the leading portion is arranged at a different location with respect to the longitudinal direction than the trailing portion,

- gathering the crimped sheet to form a gathered sheet, and

- forming a plug from the gathered sheet, wherein in the crimped sheet, the distance between two adjacent interruption bands in the longitudinal direction is smaller than half of the length of the plug in the longitudinal direction.

2. Method for producing a plug for forming part of an aerosol-generating article according to claim 1 , wherein the longitudinal distance between two adjacent interruption bands is smaller than one third of the length of the plug in the longitudinal direction.

3. Method for producing a plug for forming part of an aerosol-generating article according to claim 1 or 2, wherein the step of forming a plug from the gathered sheet comprises the steps of forming a rod out of the gathered sheet and cutting the rod to form the plug.

4. Method for producing a plug for forming part of an aerosol-generating article according to any of the previous claims, wherein the plurality of interruption bands are uniformly spaced from each other.

5. Method for producing a plug for forming part of an aerosol-generating article according to any of the previous claims, wherein an angle between the extension of the interruption bands in the crimped sheet and the longitudinal direction is between 70 degrees and 90 degrees, in particular between 75 and 85 degrees, in particular about 84 degrees.

6. Method for producing a plug for forming part of an aerosol-generating article according to any of the previous claims, wherein an interruption band width is the extension of an interruption band in the longitudinal direction, wherein the ratio of the longitudinal distance between two adjacent interruption bands to the interruption band width is between 0.5 and 5, in particular between 1 and 3, in particular about 2.

7. Method for producing a plug for forming part of an aerosol-generating article according to any of the previous claims, wherein the length of the plug in the longitudinal direction is between 5 millimeters and 20 millimeters, in particular between 7 millimeters and 17 millimeters, in particular about 12 millimeters.

8. Plug for forming part of an aerosol-generating article, wherein the plug is in particular formed according to any of the previous claims, wherein the plug extends in a longitudinal direction, wherein the plug comprises a gathered sheet, wherein the gathered sheet comprises a plurality of corrugation lines extending in the longitudinal direction, wherein at least one corrugation line of the plurality of corrugation lines is interrupted at least three times in the longitudinal direction by interruption bands, wherein each interruption band comprises a leading portion and a trailing portion, wherein the leading portion is arranged at a different location with respect to the longitudinal direction than the trailing portion, and wherein the leading portion and the trailing portion are arranged on opposite sides of the crimped sheet with respect to the width of the crimped sheet, wherein the width of the crimped sheet is the extension of the crimped sheet orthogonal to the longitudinal direction.

9. Plug for forming part of an aerosol-generating article according to claim 8, wherein the interruption bands are flat sections or sections with corrugations having a smaller corrugation amplitude compared to the rest of the corrugation lines.

10. Crimping roller, adapted to rotate around a rotation axis that extends in an axial direction, comprising a plurality of circumferential ridges, each circumferential ridge having a first ridge amplitude, and a plurality of interruption gaps, wherein in the interruption gaps, the plurality of circumferential ridges have a second ridge amplitude, wherein the second ridge amplitude is smaller than the first ridge amplitude, wherein the interruption gaps extend at an angle of less than 30 degrees with respect to the axial direction, wherein at least three interruption gaps intersect a straight line along the axial direction on a circumferential surface of the crimping roller.

11. Crimping roller according to claim 10, wherein each of the plurality of interruption gaps is inclined with respect to the axial direction.

12. Crimping roller according to claim 10 or 11, wherein the difference between the first ridge amplitude and the second ridge amplitude is between 0.3 millimeters and 1 millimeter, in particular about 0.3 millimeters.

13. Apparatus for crimping a sheet comprising a first crimping roller according to any of the previous claims 10 to 12 and a second crimping roller adapted to rotate around a second rotation axis, wherein the second crimping roller comprises a plurality of circumferential ridges.

14. Aerosol-generating article production machine, comprising a crimping roller according to any one of claims 10 to 12 or an apparatus for crimping a sheet according to claim 13.

15. Use of interrupted circumferential ridges on a crimping roller to form a plurality of interrupted crimp corrugations on a sheet prior to forming a plug out of the sheet, wherein the crimp corrugations extend in a longitudinal direction of the sheet, wherein the distance between two interruptions in a crimp corrugation in the longitudinal direction is smaller than half of the length of the plug in the longitudinal direction, wherein interruptions of adjacent crimp corrugations form interruption bands, wherein the interruption bands are inclined with respect to the longitudinal direction.