Roll assembly for finishing a reelable, in particular a pre-spliced, sheet material, and corresponding sheet material

Abstract

The present invention relates to a roll assembly for finishing a reelable, in particular a pre-bonded, sheet material, comprising a first embossing roll and a second embossing roll forming a roll nip therebetween for embossing the sheet material, the first roll comprising a plurality of protrusions for creating structural elements in the sheet material and the second roll comprising a plurality of recesses for receiving the protrusions, the roll nip portion formed between the first embossing roll and the second embossing roll being designed to create a locally bonded sheet material boundary at least partially surrounding the structural elements, the roll nip portion comprising at least one first conical interface portion and at least one interface portion formed substantially parallel to the roll axis.

Description

[Technical field]

[0001] The present invention relates to a roll assembly for finishing a reelable, in particular a pre-bonded, sheet material, comprising a first embossing roll and a second embossing roll, the first embossing roll and the second embossing roll forming a roll nip between them for embossing the sheet material, the first roll comprising a number of protrusions for producing structural elements in the sheet material and the second roll comprising a number of recesses for receiving the protrusions, the roll nip portion formed between the needles and the recesses being designed to create a locally bonded sheet material boundary at least partially surrounding the structural elements, the roll nip portion comprising at least one first conical bonding portion. The present invention further relates to a corresponding sheet material. [Background technology]

[0002] From US 2018 / 0228666 A1 a device for producing a liquid-absorbent nonwoven fabric with a three-dimensional structure and openings is already known. The device described herein comprises a plurality of conical needles which engage with complementary conical recesses. In the conical nips thus formed, the material to be embossed is compressed on the one hand, while on the other hand the tips of the needles form openings in the nonwoven fabric.

[0003] However, the disclosed device has the drawback that the material to be embossed is only insufficiently clamped when the openings are created, so that the material can slip in the nip during the creation of the openings, and therefore only a low level of structure uniformity can be achieved in the embossed material. Furthermore, the structures created in the nonwoven only have a uniform compressive strength, so that only compromise solutions can be considered when configuring the nonwoven with regard to absorbency and stability. Summary of the Invention

[0004] It is therefore an object of the present invention to improve either the roll assembly or the windable sheet material so that it has improved product characteristics and is more economical to manufacture.

[0005] This object is solved by the features of the independent claims. Advantageous embodiments of the invention are the subject of the drawing, the description and the dependent claims.

[0006] The roll nip section is therefore provided with at least one interface section formed substantially parallel to the roll axis. The invention has the advantage that an interface section formed parallel to the roll axis allows the rolls to be better aligned with each other in the manufacturing process. The section parallel to the roll axis fixes the rolls with each other and thus ensures a self-centering effect. As a result, the rolls can be operated at higher speeds than with devices known from the prior art. At the same time, an interface section designed parallel to the roll axis allows for an improved clamping of the material, so that the material cannot slip through the conical area and therefore openings can be created with greater precision. Furthermore, a conical interface section on the one hand and an interface section formed parallel to the roll axis on the other hand allow for the creation of areas of different compression in the material, which on the one hand allows for high material stability and on the other hand allows for the realization of a comfortable feel or good absorption properties. The sheet material can be, for example, a nonwoven fabric. The nonwoven fabric can be hydrophilic or hydrophobic. The sheet material can also be a tissue or a film. The sheet material can be monolayer, multilayer and / or laminated.

[0007] The roll nip portion may be provided with a stepped profile, which may have a plurality of conical, abutting portions formed substantially parallel to the roll axis.

[0008] A conical interface may be provided surrounding the structural element in a ring shape. It is also possible for an interface aligned substantially parallel to the roll axis to at least partially surround the conical interface. The interface aligned substantially parallel to the roll axis may be located in the plane of the pitch diameter of the first and second embossing rolls. The interface aligned substantially parallel to the roll axis may extend across the entire width of the rolls and may be provided when neither roll has a protrusion or a recess.

[0009] It is conceivable that the protrusions are designed as needles. The needles can be designed to form openings. If the protrusions are designed as needles, then as a consequence the structural elements are designed as openings. The clamping of the material by the conical joint is essentially parallel to the roll axis, which allows the needles to create openings in the sheet material in a precise and accurate manner. Alternatively, the protrusions can be designed as embossing ridges, which are intended to create structural elements designed as ridges. If the protrusions are designed as embossing ridges, then the structural elements are necessarily designed as ridges. Again, good material clamping allows the ridges to be introduced very precisely into the material.

[0010] It is conceivable that a first conical interface is formed between a conical proximal flank portion of the projection and a conical mouth portion of the recess. The projection may be disposed on a base region. The projection may extend radially away from the roll surface starting from the base region. The base region may have a width greater than the maximum width of the projection. The proximal flank portion of the projection may be provided in a foot region of the projection adjacent the base region. The recess may have a substantially cylindrical portion extending radially into the roll surface. In the mouth region relative to the roll surface, the recess may have a bevel on its upper side, thereby forming a conical opening of the recess. The projection may have a circular cross section. Alternatively, the projection may have an elliptical cross section. Thus, the projection may be essentially conical.

[0011] The interface formed substantially parallel to the roll axis may be provided between a saddle region of the protrusion formed substantially parallel to the roll axis and a shoulder region of the recess formed substantially parallel to the roll axis. The saddle region may be formed by an upper side of the embossed base. The saddle region may extend from the foot of the protrusion to an outer edge of the base region. The outer edge of the base region may have a bevel. The shoulder region may extend horizontally from an upper edge of the conical mouth portion, i.e., parallel to the roll axis. The shoulder region and the saddle region may be aligned parallel to each other.

[0012] It is also contemplated that the conical interface is directly adjacent to an interface formed substantially parallel to the roll axis. Thus, the roll nip portion creating the boundary may be located in the transition region between the foot region and the base region of the projection.

[0013] It is contemplated that the roll nip portion further includes a second conical interface portion adjacent to the interface portion formed parallel to the roll axis opposite the first conical interface portion, the first and second conical interfaces extending in opposite directions away from the interface portion formed parallel to the roll axis. The second conical interface portion may be formed by a bevel provided on an outer edge of the embossing base and a conical embossed raised portion adjacent to the bevel.

[0014] Further, the second roll may be provided with a plurality of embossed ridges for creating ridges in the sheet material, and the first roll may be provided with a plurality of recesses for receiving the embossed ridges. The second roll may have a plurality of first embossed protrusions having a first cross-section, and a plurality of second embossed protrusions having a second cross-section, the second cross-section being different from the first cross-section. The first cross-section may have an elliptical basic shape. The second cross-section may have a circular basic shape. The embossed ridges may have angled sidewalls and a flat top. A radius of 0.3 mm may be provided between the sidewalls and the flat top.

[0015] Additionally, a second conical interface may be provided formed between the conical proximal flank portion of the embossed ridge and the conical mouth portion of the recess.

[0016] It is conceivable that the roll nip thickness at the interface formed substantially parallel to the roll axis is between 0.01 mm and 0.03 mm, preferably 0.02 mm. It may be provided that the roll nip thickness at the interface formed substantially parallel to the roll axis is smaller than the roll nip thickness at the first and / or second conical interface. The smaller roll nip thickness at the roll nip portion essentially parallel to the roll axis ensures a better clamping and a higher compression of the material. This results in a higher material stability at the interface extending parallel to the roll axis.

[0017] For example, the roll nip thickness at the first and / or second conical interface may be provided to be between 0.02 mm and 0.08 mm, preferably 0.05 mm.

[0018] Furthermore, the height of the first conical bonded portion can be between 0.2 mm and 0.6 mm, preferably 0.4 mm, so that the opening in the material has a circular conical ring structure of bonded material surrounding the opening.

[0019] Furthermore, the height of the second cone-shaped bonding portion can be between 0.2 mm and 0.6 mm, and is preferably 0.4 mm. As a result, the embossed structure in the material has a cone-shaped ring structure made of the bonding material surrounding the embossed structure.

[0020] The width of the joints formed substantially parallel to the roll axis can be provided to be between 0.5 and 1 mm, preferably 0.7 mm. The material areas joined parallel to the material plane and surrounding the opening in a brim-like manner also ensure that the three-dimensional material structure of the sheet material has higher resistance. By adjusting the size of the joints essentially parallel to the material plane, the basic strength of the produced sheet material can be configured.

[0021] It is contemplated that the angle of the first conical interface with respect to the vertical is between 10° and 18°, preferably 14°.

[0022] In addition, the angle of the second conical interface relative to the vertical may be provided to be between 10° and 18°, preferably 14°.

[0023] Additionally, a first conical interface portion may be provided in parallel alignment with a second conical interface portion.

[0024] Furthermore, a device for heating the roll surface can be provided on the first embossing roll and / or on the second embossing roll. By setting an optimal embossing temperature in combination with a given embossing pressure, the desired three-dimensional sheet material structure can be produced particularly advantageously at high process speeds.

[0025] The invention further relates to a rollable, in particular pre-bonded, sheet material, which comprises: at least one pre-joined layer of sheet material extending in one plane; a plurality of structural elements distributed on the layer of sheet material; Each structural element has a boundary that at least partially surrounds the structural element and is formed by local bonding of the sheet material, the boundary having at least one first conical portion and at least one portion formed substantially parallel to a plane.

[0026] The boundary may have a stepped profile. The stepped profile may have a number of conical portions and a number of portions formed substantially parallel to a plane.

[0027] A first conical portion can be provided immediately adjacent the opening. Further, the portion formed substantially parallel to the plane can be directly adjacent to the first conical portion.

[0028] Furthermore, the boundary may be provided with a second conical portion adjacent to the portion formed substantially parallel to the plane opposite the first conical portion. The first conical portion may be provided to surround the structural element in a ring shape. Alternatively, the portion formed substantially parallel to the plane may partially surround the first conical portion. The structural element may be designed as an opening. The structural element may be designed as a ridge. The portion formed substantially parallel to the plane may be provided anywhere on the sheet material layer that does not have any structural element such as a ridge, a recess or an opening.

[0029] Additionally, the sheet material may be provided further having a plurality of ridges extending away from the plane.

[0030] Additionally, a second conical portion may also be provided immediately adjacent the ridge.

[0031] Exemplary embodiments of the invention will now be described with reference to the following drawings. [Brief description of the drawings]

[0032] [Figure 1] 1 illustrates a front view of an embodiment of a roll assembly in accordance with the present invention. [Diagram 2] 1 shows a plan view of a roll portion of a first embossing roll embodiment. [Diagram 3] 1 shows an enlarged cross-sectional view of one embodiment of a first embossing roll. [Figure 4] 1 is a plan view of a roll portion of a first and second embossing roll embodiment; FIG. [Diagram 5] 1 shows an enlarged cross-sectional view of an embodiment of a second embossing roll. [Figure 6] FIG. 2 illustrates an enlarged cross-sectional view of one embodiment of an embossing nip formed between a first embossing roll and a second embossing roll. [Figure 7] 1 shows an exemplary embodiment of a rollable, particularly pre-bonded, sheet material in cross section. [Figure 8]1 shows an enlarged cross-sectional view of a further embodiment of an embossing nip formed between a first embossing roll and a second embossing roll. [Figure 9] 1 shows an enlarged cross-sectional view of a further embodiment of an embossing nip formed between a first embossing roll and a second embossing roll. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The roll assembly 1 shown in FIG. 1 comprises a first embossing roll 2 and a second embossing roll 3 forming a roll nip 4. It can be seen that a number of needles 5 are arranged in a regular distribution on the first embossing roll 2. The needles 5 are at the same distance from all adjacent needles 5. Of course, the needles 5 can also have different distances from each other. A number of first recesses 17.1 with an elliptical cross section and a number of second recesses 17.2 with a circular cross section are arranged between the needles. The ratio of the first recesses 17.1 to the second recesses 17.2 is 1:3. On the second embossing roll 3, an embossing structure is formed that is complementary to the structure of the first embossing roll. On the one hand, the second embossing roll comprises a number of recesses 6 that are aligned in such a way that the needles 5 are received in the recesses 6 when the rolls 2, 3 rotate relative to each other. Similarly, in a complementary arrangement, the second embossing roll further includes a plurality of first embossing ridges 16.1 and a plurality of embossing ridges 16.2 which engage corresponding recesses 17.1, 17.2 in the roll nip 4. Corresponding to the recesses 17.1, 17.2, the first embossing ridges 16.1 have an elliptical cross-section and the second embossing ridges 16.2 have a circular cross-section.

[0034] FIG. 2 shows a plan view of the embossing structure of the first embossing roll 2. The embossing structure comprises a number of needles 5, a number of first recesses 17.1 with an elliptical cross section, and a number of second recesses 17.2 with a circular cross section. It can be seen that each needle 5 is surrounded by three second recesses 17.2 with a circular cross section and a first recess 17.1 with an elliptical cross section. The first recess 17.1 with an elliptical cross section can be located to the left, right, above or below the needle 5. The maximum width B3 of the needle 5, i.e. the width of the foot region of the needle 5 adjacent to the base region 21, is 2.2 mm in the illustrated embodiment. The first and second recesses 17.1, 17.2 each have a conical mouth portion 19 at their upper edge facing the roll surface, which mouth portion is designed in the shape of a bevel surrounding a ring-shaped recess. The width of the conical mouth portion 19 of both recesses 17.1, 17.2 is 0.2 mm in the embodiment shown.

[0035] FIG. 3 shows an enlarged cross-sectional view of the embossing roll structure of the first embossing roll 2. In particular, a cross-sectional view of the needle 5 can be seen. The needle 5 has an essentially conical shape arranged on and extending away from the base region 21. The base region has a width greater than the width B3 of the foot region of the needle 5. The upper side of the base region 21 is at the level of the pitch circle diameter of the roll. The height H1 of the needle 5 is 3.2 mm in the illustrated embodiment. At the top of the needle 5 there is a needle tip 20 with a height H2, which in the illustrated embodiment is 1.07 mm. The needle tip 20 has a flank angle β that is less acute than the lower region of the needle 5 with a flank angle α, where β>α. In the illustrated example, α is 14° and β is 28°. The lower region of the needle 5 provides a conical proximal flank portion 11, from which a first conical portion of the boundary of the opening in the sheet material is created. The essentially horizontal saddle region 13 of the needle 5 is formed by the upper side of the base region 21 which projects horizontally beyond the needle cross section and serves to create an essentially horizontally formed boundary interface 9. The conical mouth portions 19 of the four recesses 17.1, 17.2 surrounding the needle 5 adjoin the saddle region 13. These then partially form the second conical interface 15 together with the complementary embossed ridges 16.1, 16.2. The recesses 17 each have a depth T2, which in the illustrated example is 1.8 mm. The height H5 of the conical mouth portions 19 of the recesses 17 is 0.4 mm in the illustrated embodiment. The conical mouth portions have an angle γ with the vertical, which in the illustrated example is 14°.

[0036] FIG. 4 shows a plan view of the embossing structure of the second embossing roll 3. The embossing structure has a plurality of depressions 6 and further has a plurality of first embossing ridges 16.1 with an elliptical cross section and a plurality of second embossing ridges 16.2 with a circular cross section. According to FIG. 2, it can be seen that each depression 6 is surrounded by three second embossing ridges 16.2 with a circular cross section and a first embossing ridge 16.1 with an elliptical cross section. The first embossing ridge 16.1 with an elliptical cross section can be located to the left, right, above or below the needle 5. The width B1 of the depression 6, i.e. the width of the depression cylinder extending on the roll surface, is 2.1 mm in the illustrated embodiment. The first and second embossing ridges 16.1, 16.2 each have a rounded upper edge facing away from the roll surface, with a radius of 0.3 mm in the illustrated embodiment. The width of the conical mouth portion 12 of the recess 6 is 0.2 mm in the embodiment shown.

[0037] FIG. 5 shows an enlarged cross-sectional view of the embossing roll structure of the second embossing roll 3. In particular, a cross-sectional view of the depression 6 can be seen. The depression 6 is arranged between the embossing ridges 16 and has an essentially cylindrical shape extending into the roll surface with a width B1 and a depth T1, which in the illustrated embodiment is 2.1 mm and 4 mm. At the upper edge of the mouth area of ​​the depression 6, the depression 6 has a width of 2.3 mm. This width is therefore greater than the maximum width B3 of the needle 5, and the depth T1 is greater than the height H1 of the needle 5. The mouse angle of the mouse area 12 has an angle α of 14°. The shoulder area 14 surrounding the upper edge of the depression lies in the plane of the pitch diameter of the roll. The conical mouth area 12 of the depression 6 functions in cooperation with the conical proximal flank portion 11 of the needle to create a first conical portion of the boundary of the opening in the sheet material. The essentially horizontal shoulder region 14 of the recess 6 together with the horizontal saddle region 13 of the needle 5 serves to create an essentially horizontally formed interface 9 of the boundary. A conical flank portion 18 of the embossed ridge 16 of the four embossed ridges 16.1, 16.2 surrounding the recess 6 adjoins the shoulder region 14. Its proximal region then partially forms the second conical interface 15 together with the complementary recesses 17.1, 17.2. Each of the embossed ridges 16 has a height H3, which in the illustrated example is 1.4 mm. Each of the conical flank portions 18 of the embossed ridges has an angle γ with the vertical, which in the illustrated example is 14°.

[0038] FIG. 5 finally shows an enlarged cross-sectional view of an embodiment of the embossing nip 4 formed between the first embossing roll 2 and the second embossing roll 3. When the embossing rolls 2, 3 roll against each other, the embossing ridge 16 of the second embossing roll 3 engages with the recess 17 of the first embossing roll 2 when passing through the embossing nip 4. The second conical interface 15 is formed by the conical proximal flank portion 18 of the embossing ridge 16 and the conical mouth portion 19 of the recess 17 meeting and aligned parallel to each other. It has a height of H5. The interface 15 is defined on the upper side by the substantially horizontal shoulder area 14 of the recess 6 and on the lower side by the fact that the embossing nip widens due to the vertical course of the side wall of the recess 17 adjacent to the interface 15 below. The interface 15 has an embossing nip thickness D1 of 0.05 mm.

[0039] When the embossing rolls 2, 3 roll against each other, the needles 5 of the first embossing roll 2 also engage the recesses 6 of the second embossing roll 3 as they pass through the embossing nip 4. An essentially horizontal interface 9 is formed in the area where the essentially horizontal saddle area 13 of the base area 21 and the essentially horizontal shoulder area 14 of the recesses 6 meet, which are aligned parallel to each other. It has a width of B2. The interface 9 is defined on the side facing outward from the needles 5 by the conical proximal flank portion 18 of the embossing ridge 16 and on the side facing the needles 5 by the conical proximal flank portion 11 of the needles 5. The interface 9 has an embossing nip thickness D2 of 0.02 mm and therefore produces a greater clamping and a greater material compression than the conical interface areas 15 and 8.

[0040] The first conical interface 8 is formed in the area of ​​the intersection of the conical proximal flank portion 11 of the needle 5 and the conical mouth portion 12 of the recess 6, which are aligned parallel to each other. It has a height H4. The interface 8 is defined on its lower side by the essentially horizontal saddle area 13 of the base area 21 and on its upper side by the fact that the embossing nip widens due to the vertical course of the side wall of the recess 6 adjacent to the interface 8 as seen from above. The first conical interface 8, like the second conical interface 15, has an embossing nip thickness D2 of 0.05 mm. Adjacent interfaces 8, 9, 15 form a stepped profile 10.

[0041] FIG. 7 shows an exemplary embodiment of a rollable, in particular pre-bonded, sheet material 22 in a cross-sectional view. The sheet material 22 has a rollable sheet material layer 23 extending in a plane, the sheet material layer 23 having a plurality of openings 24 extending through the sheet material layer 23. Each opening 24 has a boundary 25 surrounding the opening 24, the boundary 25 being characterized by a localized joining of the sheet material 22. The boundary 25 has a first conical portion 26 and a portion 27 formed substantially parallel to the plane. Furthermore, the boundary 25 has a second conical portion 28 opposite the first conical portion 26 and adjacent to the portion 27 formed substantially parallel to the plane. As a result, the boundary 25 has a stepped profile. The first conical portion 26 is immediately adjacent to the opening 24. The portion 27 formed substantially parallel to the plane is directly adjacent to the first conical portion 26. The sheet material further includes a plurality of ridges 29 extending away from the plane, with the second conical portions 28 immediately adjacent adjacent ridges 29 .

[0042] FIG. 8 shows a further embodiment of the invention. In this case, the first embossing roll 2 has only needles 5 as structural elements, and the second embossing roll 3 has dedicated corresponding depressions 6. When the needles 5 engage the depressions 6, the sheet material is joined or perforated in the roll nip 4. In the horizontal joint 9 and in the first conical joint 8 adjacent to the horizontal joint 9 and surrounding the needles 5 in the foot region of the needles 5 in a ring shape, the material to be perforated is clamped so that the needle tips 20 can create openings in the material precisely. Also in this embodiment, the first conical joint 8 is formed between the conical proximal flank 11 of the needles 5 and the conical mouth of the depressions 6. The joint 9, which is formed essentially parallel to the roll axis, is created in the roll nip portion formed by the rolling circle diameter of the first embossing roll 2 and the second embossing roll 3, which extends over the entire roll width where the needles 5 or depressions 6 are not located.

[0043] FIG. 9 shows yet another embodiment of the invention, where the first embossing roll 2 has only embossing ridges 5 as structural elements and the second embossing roll 3 has only corresponding depressions 6 as structural elements. The embossing ridges 5 engage the depressions 6 when passing through the roll nip 4, but instead of openings, they only create bumps or bulges in the material to be structured. The embossing ridges 5 each have a conical flank, the conical proximal portion 11 of which, in the foot region of the embossing ridges 5, together with the conical mouth portion 12 of the depressions 6, form a first conical joining portion 8 of the roll nip 4. The conical joining region 8 surrounds the entire embossing ridge 5 in a ring shape. The interface 9, which is formed essentially parallel to the roll axis, is produced in the roll nip portion formed by the rolling circle diameters of the first embossing roll 2 and the second embossing roll 3 according to the embodiment of FIG. 3 and extends over the entire roll width if no needles 5 or depressions 6 are arranged.

[0044] The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for the implementation of the invention both individually and in any combination. [Explanation of symbols]

[0045] 1 Roll Assembly 2. First embossing roll 3. Second embossing roll 4 Roll Nip 5. Protuberances, needles, embossed ridges 6. Depression 7 Roll nip area 8 First cone-shaped joint 9 Joints formed essentially parallel to the roll axis 10 Step Profile 11 Conical proximal flank of needle 12 Cone-shaped mouth part 13. A saddle region of the base region formed essentially parallel to the roll axis 14 Shoulder area of ​​the recess formed essentially parallel to the roll axis 15 Second cone-shaped joint 16 Embossed raised area 16.1 Embossed ridge having a first cross section 16.2 Embossed ridge having second cross section 17 Recess 17.1 Recess having a first cross section 17.2 Recess with second cross section 18 Conical proximal flank of embossed ridge 19 Concave cone-shaped mouth part 20 Needle Tip 21 Base Area 22 Sheet material 23 Sheet material layer 24 Opening 25 Boundary 26 First cone-shaped part 27 Parts formed substantially parallel to a plane 28 Second cone-shaped part 29 Ridge B1 Depression width B2 Width of the portion formed substantially parallel to the roll axis B3 Maximum needle width D1 Conical embossing nip thickness D2 Horizontal embossing nip thickness H1 needle height H2 needle tip height H3 Height of embossed ridge H4 Conical proximal flank of embossed ridge H5 Height of the conical mouth part of the recess T1 Depth of the depression T2 Recess depth α Angle of the conical proximal flank of the needle β Needle tip angle γ The angle of the conical mouth part of the recess

Claims

1. 1. A roll assembly for finishing a rewilable, in particular pre-bonded, sheet material, comprising: a first embossing roll and a second embossing roll forming a roll nip therebetween for embossing the sheet material; the first roll having a plurality of protrusions for creating structural elements in the sheet material, and the second roll having a plurality of recesses for receiving the protrusions; a roll nip portion formed between the first embossing roll and the second embossing roll is designed to create a locally bonded boundary of sheet material that at least partially surrounds the structural element, the roll nip portion having at least one first conical bonding portion; The roll nip portion further comprises at least one splicing portion formed substantially parallel to the axis of the roll. The roll assembly.

2. The roll assembly of claim 1 , wherein the roll nip portion has a stepped profile.

3. 2. The roll assembly of claim 1, wherein the first conical bonding portion is formed between a conical proximal flank portion of the projection and a conical mouth portion of the recess.

4. 2. The roll assembly of claim 1, wherein the bonding portion formed substantially parallel to the roll axis is formed between a saddle region of the protrusion aligned substantially parallel to the roll axis and a shoulder region of the recess aligned substantially parallel to the roll axis.

5. 2. The roll assembly of claim 1, wherein the first conical splicing portion is directly adjacent the splicing portion formed substantially parallel to the roll axis.

6. 6. The roll assembly of claim 5, wherein the first conical splicing portion surrounds the structural element in a ring shape.

7. 6. The roll assembly of claim 5, wherein the splicing portion aligned substantially parallel to the roll axis partially surrounds the first conical splicing portion.

8. 2. The roll assembly of claim 1, wherein the protrusions are needles provided to create structural elements designed as openings.

9. 10. The roll assembly of claim 1, wherein the protrusions are embossing ridges provided to create structural elements designed as ridges.

10. 2. The roll assembly of claim 1, wherein the roll nip portion further includes a second conical splicing portion opposite the first conical splicing portion and adjacent to the splicing portion formed substantially parallel to the roll axis, the first conical splicing portion and the second conical splicing portion extending in opposite directions away from the splicing portion formed substantially parallel to the roll axis.

11. 2. The roll assembly of claim 1, wherein the second roll has a plurality of embossing ridges for creating ridges in the sheet material, and the first roll has a plurality of recesses for receiving the embossing ridges.

12. 11. The roll assembly of claim 10, wherein the second conical bonding portion is formed between a conical proximal flank portion of the embossing ridge and a conical mouth portion of the recess.

13. 2. The roll assembly according to claim 1, wherein the thickness (D2) of the roll nip in the splicing portion formed substantially parallel to the roll axis is between 0.01 mm and 0.03 mm, preferably 0.02 mm.

14. 11. The roll assembly according to claim 1 or 10, wherein the roll nip thickness (D1) of the first conical joining portion and / or the second conical joining portion is between 0.02 mm and 0.08 mm, preferably 0.05 mm.

15. 2. A roll assembly according to claim 1, wherein the height (H4) of the first conical splicing portion is between 0.2 mm and 0.6 mm, preferably 0.4 mm.

16. 11. A roll assembly according to claim 10, wherein the height (H5) of the second conical splicing portion is between 0.2 mm and 0.6 mm, preferably 0.4 mm.

17. 2. The roll assembly according to claim 1, wherein the width (B2) of the joining portion formed substantially parallel to the roll axis is between 0.5 mm and 1 mm, preferably 0.7 mm.

18. 2. The roll assembly of claim 1, wherein the angle (α) of the first conical splicing section with respect to the vertical is between 10° and 18°, preferably 14°.

19. 11. The roll assembly according to claim 10, wherein the angle (γ) of the second conical splicing portion with respect to the vertical is between 10° and 18°, preferably 14°.

20. 11. The roll assembly of claim 10, wherein the first conical splicing portion is aligned parallel to the second conical splicing portion.

21. 2. The roll assembly of claim 1, wherein the first embossing roll and / or the second embossing roll is provided with a device for heating the surface of the roll.

22. A rollable, in particular pre-bonded, sheet material, at least one layer of rollable sheet material extending in a plane; a plurality of structural elements distributed on the at least one layer of sheet material; Including, each of the structural elements having a boundary at least partially surrounding the structural element and formed by local bonding of the sheet material, the boundary having at least one first conical portion, the boundary further having at least one portion formed substantially parallel to the plane; The sheet material.

23. 23. The sheet material of claim 22, wherein the boundary has a stepped profile.

24. 23. The sheet material of claim 22, wherein the first conical portion is directly adjacent the structural element.

25. 23. The sheet material of claim 22, wherein the portion formed substantially parallel to the plane is immediately adjacent to the first conical portion.

26. 26. The sheet material of claim 25, wherein the first conical portion surrounds the structural element in a ring shape.

27. 26. The sheet material of claim 25, wherein the portion formed substantially parallel to the plane partially surrounds the first conical portion.

28. 23. The sheet material of claim 22, wherein the structural elements are formed as apertures.

29. 23. The sheet material of claim 22, wherein the structural elements are formed as ridges.

30. 23. The sheet material of claim 22, wherein the boundary has a second conical portion opposite the first conical portion and adjacent the portion formed substantially parallel to the plane.

31. 23. The sheet material of claim 22, wherein the sheet material further comprises a plurality of ridges extending away from the plane.

32. 31. The sheet material of claim 30, wherein the second conical portion is further directly adjacent the ridge.

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