WO2025168570A1

WO2025168570A1 - Hydroentanglement shell, assembly thereof with a carrier, manufacturing method of the hydroentanglement shell and nonwoven fabric manufacturing method

Info

Publication number: WO2025168570A1
Application number: PCT/EP2025/052833
Authority: WO
Inventors: Albrecht GEBHARD; Johannes Martin KRANENBURG; Cornelis Johannes Jeckmans
Original assignee: SPGPrints BV
Current assignee: SPGPrints BV
Priority date: 2024-02-05
Filing date: 2025-02-04
Publication date: 2025-08-14
Anticipated expiration: 2026-08-05

Abstract

The invention concerns a hydroentanglement shell (16), in particular for manufacturing nonwoven fabrics (12), preferably a non-apertured nonwoven, by means of a web bonding process using fluid jets (20). The shell (16) comprises a body comprising interconnected dams (36). The body has a front side (52) directed to the fluid jets during use thereof and a back side (54) opposite to the front side (52). The dams (36) delimit openings (34) configured for allowing fluid to pass through from the front side to the back side. The dams (36) have a profiled fluid jet rebounding surface (50) that is configured for establishing a sideways directed rebounding effect of the fluid jet. In an embodiment the rebounding surface (50) comprises differently sloping parts (38, 40, 44, 44', 46) at the front side (52).

Description

HYDROENTANGLEMENT SHELL, ASSEMBLY THEREOF WITH A CARRIER, MANUFACTURING METHOD OF THE HYDROENTANGLEMENT SHELL AND NONWOVEN FABRIC MANUFACTURING METHOD

TECHNICAL FIELD

The present invention relates to a hydroentanglement shell, in particular for manufacturing nonwoven fabrics by means of a web bonding process using fluid jets, and to an assembly thereof comprising a carrier having at least one hydroentanglement shell assembled thereon. In addition the present invention relates to a manufacturing method of the hydroentanglement shell and a nonwoven fabric manufacturing method using the hydroentanglement shell.

BACKGROUND OF THE INVENTION

A hydroentangling (also sometimes referred to as spunlacing) technique for manufacturing nonwoven fabrics (hereinafter also referred to as nonwovens) having a homogenous surface look (without pattern or relief) involves providing nonwoven starting materials, such as for examples fibers, filaments, ribbons, flakes and the like that are applied (under pressure) as a web thereof on a support provided with openings (also known as a shell), such as a (rotary) screen having a plurality of (micro-) holes. Such a shell can be made from woven mesh or by laser drilling holes into a thin metal cylinder. Another example is a shell made by electroforming. A number of jets of a fluid, such as a liquid like water or a gas, is directed under pressure to the exposed surface of the starting materials thereby forming a compacted and consolidated web by entanglement of the starting materials. The fluid from the jets crosses the web and is rebounded back from the perforated support. The combination of direct and deflected (rebounded) jets causes entanglement from both sides. Examples of the perforated support include a belt or a flat, curved or cylindrical shell. Typically a thin perforated support is supported by a suitable carrier provided with drainage holes for removing the fluid, at least in case of liquids like water, that has lost its speed and therefore energy to establish entanglement.

The configuration of the shell surface may allow for patterns to form in the back of the nonwoven web as an impressed relief.

EP0776391 B1 has disclosed a process for the manufacture of nonwoven unpatterned cloth using pressured waterjets, comprising passing a base cloth made from elementary fibers over a perforated rotating drum, a partial vacuum being applied within said drum and the surface of said drum being provided with a large number of micro-holes; and directing a row of said pressured waterjets at said rotating drum bearing said cloth, the micro-holes of said drum being distributed in a random manner.

EP0223614A2 has disclosed that the perforated support has a sufficient hardness to generate the rebounding streams when the jetted water streams strike thereagainst and thereby to permit these rebounding streams to contribute to promotion of fiber entanglement. The perforated support could be a cylinder, a travelling endless belt or a semi-spherically curved stationary plater. In an embodiment as shown in Figs. 6-8 thereof the support comprises a plurality of projections for aperture formation in the fibrous web at a predetermined pitch and a plurality of drainage holes formed in a regular array in zones of the surface between adjacent projections. The projections preferably have a shape which gradually diverges from its apex towards its base such as a semi-sphere in order to improve an efficiency at which apertures are formed in the fibrous web and to facilitate peeling off of the nonwoven fabric from the support. To form clearly defined apertures in the nonwoven fabric, it is preferred that each of the projections has a diameter of 0.3 to 15 mm and a height of 0.4 to 10 mm. The projections are preferably arranged at a pitch of 1 to 15 mm. The projections themselves may also have drainage holes. Then the drainage holes preferably have a diameter of 0.2 to 2.0 mm and total area thereof preferably occupies 2 to 35% of the effective surface area of the support. It is believed that the fibers are enforced by the water jets to slide sideways along the surface of the projections thereby forming the apertures in the nonwoven fabric.

CN112981709A has disclosed a spunlace processing technology for manufacturing nonwovens, wherein the entanglement is said to be improved by changing the rebounding functionality of the support, in particular by the provision of an eccentric drainage filter screen having a self-heating rebound wheel, which screen is said to achieve a basic static rebound and a multi-directional strong dynamic rebound. This screen is very complex and is complicated to assemble, and its function due to the presence of driving ropes between the rebound wheel and a water wheel is unreliable, as well as uncontrolled heating by the irregular movement of friction balls in the plates of the rebound wheel.

Therefore a need to improve the entanglement effect by changing the rebounding effect continues to exist.

An object of the present invention is to provide a hydroentanglement shell for manufacturing nonwovens having a uniform appearance, in particular unpatterned nonwovens, of which the fluid jet rebounding effect and/or water (energy) efficiency are improved.

Another object of the present invention is to provide such a hydroentanglement shell, of which the entanglement effect is enhanced in a direction perpendicular to the machine direction. Yet another object of the present invention is to provide a method of manufacturing a hydroentanglement shell, in particular by electroforming, having an improved effect on entanglement.

SUMMARY OF THE INVENTION

The invention is based on improving the fluid jet rebounding properties of a hydroentanglement shell by the design of the shell. In view thereof the surface of the shell between the openings or drainage holes is provided with a rebounding profile that is configured for establishing a sideways directed rebounding effect of the fluid jet.

Thus the invention concerns a hydroentanglement shell for manufacturing nonwoven fabrics in particular a non-apertured nonwoven, by means of a web bonding process using fluid jets, comprising a body comprising interconnected dams, wherein the body has a front side directed to the fluid jets during use thereof and a back side opposite to the front side, wherein the dams delimit openings configured for allowing fluid to pass through from the front side to the backside, and wherein the dams have a profiled fluid jet rebounding surface at the front side of the shell that is configured for establishing a sideways directed rebounding effect of the fluid jet. By providing a highly varying fluid jet rebounding surface at the front side of the shell, the fluid jets will be reflected in a more diffuse way, which improves the entanglement. In an embodiment of the invention a hydroentanglement shell for manufacturing nonwoven fabrics, in particular a non-apertured nonwoven, by means of a web bonding process using fluid jets, comprises a body comprising interconnected dams, wherein the body has a front side directed to the fluid jets during use thereof and a back side opposite to the front side, wherein the dams delimit openings configured for allowing fluid to pass through from the front side to the backside, and wherein the dams have a profiled fluid jet rebounding surface comprising differently sloping parts at a negative angle with respect to the front side. By providing such an highly varying fluid jet rebounding surface having a plurality of differently sloping parts at a negative angle with respect to the front side, the fluid jets will be reflected in a more diffuse way, which improves the entanglement. ‘Differently sloping’ is defined with respect to the direction of the fluid jets, which direction is typically perpendicular to the shell’s front side.

Furthermore, the use of the hydroentanglement shell according to the invention allows to increase the water efficiency. That is to say, for achieving the same strength of a nonwoven made using a prior art shell, less water and/or less water pressure is needed when using the hydroentanglement shell according to the invention. A reduction in water pressure and/or water consumption also results in a lower energy consumption.

In a further aspect the invention provides a preferred method of manufacturing a hydroentanglement shell according to the invention, comprising the steps of providing a support having a surface provided with conductive areas corresponding to the body of interconnected dams to be formed and non-conductive areas corresponding to the openings to be left in the body; depositing metal on the conductive areas from a solution comprising metal ions thereby forming an electroform comprising the body of interconnected dams delimiting openings, wherein the conductive areas and non-conductive areas are arranged and the deposition of metal is performed such that the dams in the network have a profiled fluid jet rebounding surface, such as differently sloping parts at a negative angle with respect to the front side of the hydroentanglement shell; separating the electroform from the support.

This manufacturing method is based on the controlled growth of a metal on the conductive areas of the support to create a hydroentanglement shell comprising a profiled fluid jet rebounding surface at its front side, for example resulting in differently sloping parts in the dams, resulting in improved entanglement.

The invention also relates to an assembly of a carrier provided with a plurality of drainage openings and a hydroentanglement shell according to the invention, mounted on the carrier. In yet another aspect the invention provides a method of manufacturing a nonwoven fabric by web bonding through entanglement of fibers caused by fluid jets, comprising the steps of providing a web of fibers; jetting at least one fluid jet on the web of fibers while the web is supported by the hydroentanglement shell or an assembly according to the invention.

BRIEF DESCRIPTION OF THE DRAWING

The invention is further illustrated in the attached drawing, wherein:

Fig. 1 shows a diagram of an embodiment of a spunlace system for the production of nonwovens;

Fig. 2 shows diagrammatically a detail of the hydroentanglement process using an assembly of a carrier and a rotary hydroentanglement shell;

Fig. 3 shows an embodiment of a hydroentanglement shell according to the invention;

Fig. 4 shows a cross section A-A’ of the embodiment of Fig. 3;

Fig. 5 shows another cross section B-B’ of the embodiment of Fig. 3; and

Fig. 6 shows an embodiment of a design of conductive areas and non-conductive areas on a support for electroforming the embodiment of a hydroentanglement shell of Fig. 3;

Fig. 7 shows a photograph of an electroformed hydroentanglement shell manufactured from a design similar to Fig. 6; Fig. 8 shows another embodiment of a design of conductive parts and non-conductive parts on a support for electroforming an embodiment of a hydroentanglement shell according to the invention;

Fig. 9 is a diagram showing the fabric density as function of the pump pressure for different hydroentanglement shells;

Fig. 10 is a diagram showing the strength in the cross direction as function of the jetting pressure for different hydroentanglement shells; and.

Fig. 11 is a diagram showing the strength in the machine direction as function of the jetting pressure for different hydroentanglement shells.

DETAILED DESCRIPTION OF THE INVENTION

The invention is based on improving the fluid jet rebounding properties of a hydroentanglement shell by the design of the shell, in particular the provision of a profiled fluid jet rebounding surface of the dams at the front side of the shell which profiled fluid jet rebounding surface is configured to establish a sideways directed rebounding effect of the fluid jet, such as differently sloping parts at a negative angle with respect to the front side in the interconnected dams forming the body of the shell .

The hydroentanglement shell according to the invention comprises a body of interconnected dams. The body has a back side and a front side opposite thereto. During use the front side is directed to the waterjets. The back side is the water discharging side of the hydroentanglement shell. The dams delimit through openings which allow passage of the fluid from the front side to the back side. At the front side the dams have a fluid jet rebounding surface. According to the invention the fluid jet rebounding surface of the dams at the front side of the shell is profiled to establish a sideways directed rebounding effect of the fluid jets. In an embodiment the profiled fluid jet rebounding surface of the dams comprises parts that have different slopes. Hereinafter these parts may be also referred to as (scattering) faces. E.g. the dams, in addition to side flanks sloping towards the openings, may have faces at the front side, that are not perpendicular to the direction of the fluid jets. These deflecting faces scatter the fluid jets back in various directions at angles with respect to incoming fluid jets, thereby contributing to the entanglement of the fibers from the back side of the fibrous web. In other words the front side of the dams is provided with additional scattering faces that are not perpendicular to the direction of the waterjets but oriented at an angle. Taking the front side of the shell as a reference the angle is negative. Thus sloping faces form recesses instead of projections, the latter having a positive angle with respect to the front side.

In prior art shells the openings have a circular cross section and the top surface of the dams delimiting the openings is substantially flat. The direction of the rebounded water is therefore mainly in the same, though opposite direction as the waterjets from the waterjet station. In the hydroentanglement shell according to the invention the total area of sloping surfaces and shape (orientation and angle) thereof is increased with respect to a circular hole pattern, and therefore scattering of rebounding water is enhanced which improves the strength of the nonwoven manufacturing using the hydroentanglement shell according to the invention. The sloping flanks of the recesses can be designed and manufactured to establish a preferential direction for the rebounding water. E.g. it has been found that nonwovens always show a higher strength in the machine direction MD than in the cross direction CD (= length direction of a rotary shell). In order to have more uniform (isotropic) properties of the nonwoven the rebounding effect could be preferentially increased to the sides.

In an embodiment the fluid rebounding surface comprises different faces that differ from one another by difference in slope direction and/or difference in slope angle with respect to the direction of the fluid jets, that is typically perpendicular to the plane of the body.

In an embodiment the fluid jet rebounding surface comprises recessed parts (hereinafter also referred to as valleys) that have a height, measured from the back side to the front side, that is lower than the height of ridges surrounding these recessed parts (valleys). Such valleys are, unlike the openings, recesses in the body of the interconnected dams, which do not allow for passage of the fluid there through. Advantageously these valleys are positioned at connecting parts, which connecting parts connect two or more dams in the body network. In a further embodiment thereof the ridges have flanks sloping towards the valleys. The differently sloping flanks in the fluid jet rebounding surface scatter the fluid jets back in different directions thereby contributing to the entanglement of the fibers from the back side. In an embodiment the valleys have an elongated shape, such as an elliptical shape.

In an embodiment side flanks of adjacent dams that slope towards a through-opening are connected, thereby also forming a recessed area.

The shape of the dams that delimit the openings may be designed to further improve the back scattering effect. In particular the variation in slope orientation and/or slope angle with respect to the plane of the fluid jets may be increased. In an embodiment the openings have a noncircular cross section, such as an elliptical or droplet cross section. Preferably, in top view the mouth of an opening at the first side has a non-circular shape.

Typically the longest dimension of the openings is in the range of 100-450 pm, preferably 250-320 pm. The larger the profiled fluid jet rebounding surface area the larger the rebounding effect is. In view of increasing the total area of the profiled fluid jet rebounding surface, while maintaining sufficient drainage (suction) capacity the open area is typically in the range of 4.5-10%, such as 5-8.5%.

By arranging the scattering faces in a predefined orientation the rebounding effect can be controlled, at least to a certain extent. E.g. it has been observed that nonwovens have a higher strength in the machine direction than in the cross direction. Strength in the cross direction can be improved by enhancing the rebounding effect in this direction. In an embodiment the fluid jet rebounding surface is configured for rebounding fluid jets mainly in a plane perpendicular to the machine direction. Examples thereof include the elongated valleys mentioned above or grooves, that may remain open, the main flanks of which mainly extend in the machine direction. Then the flanks are mainly facing in cross direction, thereby effecting additional entanglement in cross direction.

In an embodiment the shell is an electroformed metal shell. Advantageously the metal is nickel or a nickel alloy.

The hydroentanglement shell may have a plate shape. In an embodiment the hydroentanglement shell has the shape of a cylinder.

Typically the hydroentanglement shell is supported on a carrier having drainage holes for discharging, for example through suction, the fluid, such as water.

In an aspect the invention provides an assembly of the hydroentanglement shell according to the invention and a carrier provided with a plurality of drainage holes. The hydroentanglement shell according to the invention is mounted onto the carrier.

A hydroentanglement shell according to the invention can be made using different techniques, such as by perforating such as punching or (laser) drilling for establishing the through-holes in combination with additional surface processing to provide the additional slopes. In view of the precise and small dimensions of the dams and openings in an embodiment the hydroentanglement shell is manufactured by electroforming.

A further aspect of the invention is a preferred method of manufacturing a hydroentanglement shell according to the invention, comprising the steps of providing a support having a surface provided with conductive areas corresponding to the body of interconnected dams to be formed and non-conductive areas corresponding to the openings to be left in the body; depositing metal on the conductive areas from a solution comprising metal ions thereby forming an electroform comprising the body of interconnected dams delimiting openings, wherein the conductive areas and non-conductive areas are arranged and the deposition of metal is performed such that the dams in the network have a profiled fluid jet rebounding surface that is configured for establishing a sideways directed rebounding effect of the fluid jet, e.g. a fluid jet rebounding surface comprising differently sloping parts at a negative angle with respect to the front side of the hydroentanglement shell; separating the electroform from the support.

In the manufacturing method according to the invention a support is used, which is provided with conductive areas on which the network of dams is to be formed, and non-conductive areas, typical spots which will result in the through openings, as well as spots for the valleys, if present. The support may be a mandrel or a patterned sleeve, The conductive areas define the dams to be formed. As during electroforming metal growth occurs in the height direction and in the lateral direction, typically the width of a conductive area is smaller than the width of the corresponding final dam. Likewise, the size of a non-conductive area is larger than the size of the corresponding final through-opening. The support is placed in an electroforming bath comprising an electrolyte comprising metal ions and electrically connected. Metal is deposited from this bath on the conductive areas. Initially metal is not deposited on the non- conductive areas. During further growth of metal the non-conductive areas for the through openings are overgrown partially. The non-conductive areas for the valleys and surrounding sloping parts are filled up during further growth. Once the desired thickness of the metal deposit is achieved the metal shell thus manufactured comprising the network of interconnected dams having differently sloping parts is removed from the support. It is also conceivable to deposit metal on the conductive parts of the support until a skeleton is formed, which skeleton is removed subsequently from the support and then further grown to its final thickness.

The invention also relates to a method of manufacturing a nonwoven fabric by web bonding through entanglement of fibers caused by fluid jets, comprising the steps of providing a web of fibers; jetting a fluid jet on the web of fibers while the web is supported by a hydroentanglement shell according to the invention.

DETAILED DESCRIPTION OF THE DRAWING

The invention is further illustrated by the attached drawings.

Fig. 1 shows diagrammatically an embodiment of a spunlace system 10 and method for the production of nonwovens. A web 12 of fibers is conveyed by a conveyor such as a conveyor belt schematically represented by guide rolls 14. The web 12 is guided over a rotary hydroentanglement shell 16. A waterjet station 18 for generating a plurality of water jets 20 is arranged at a circumferential position of the shell 16. Water is jetted from this station 18 through a plurality of nozzles, arranged in the cross direction to the machine direction, covering at least the width of the web 12. Typically the waterjets 20 are directed perpendicular to the web 12. Upon passing of the fibrous web 12 the waterjets 20 establish entanglement of the fibers. Water is drained from the interior of the shell 16, for example by means of a water suction device for collecting water and typically filtered in a water filtering device for removal of dust and the like of the starting materials and then recycled back to the waterjet station 18. After hydroentanglement the consolidated web 12’ is passed to a dewatering station, where water is removed, e.g. using rollers 22, and subsequently dried in dryer 24 and wound on a reel 26. In practicing the invention a nonwoven production line may comprise several hydroentanglement stages. A first hydroentanglement step of the nonwoven may be performed on the flat conveyor, followed by a second hydroentanglement step using a first cylindrical assembly according to the invention with water directed to a first, e.g. upper side of the nonwoven and then a third hydroentanglement step using a second cylindrical assembly according to the invention with water directed to the opposite e.g. bottom side of the nonwoven, while the nonwoven is conveyed past the assemblies along an S shaped conveying path.

Fig. 2 shows diagrammatically a cross section of a part of a cylindrical hydroentanglement shell 16 supported on a cylindrical carrier 28, e.g. a perforated mesh or electroformed sleeve having openings, typically much larger than the openings in the hydroentanglement shell. Together the shell 16 and carrier 28 form an embodiment of an assembly 30 according to the present invention. Entanglement of the fibers in the web 12 occurs due to the waterjets 20 originating from the waterjet station 18, as well as due to water rebounding from the shell 16. In this embodiment a water suction device such as a vacuum box 32 is arranged within the carrier 28.

Fig. 3-5 show an embodiment of a hydroentanglement shell 16 according to the invention, which allow scattering the rebounding waterjets in a more diffuse way. In the embodiment shown the shell 16 has through openings 34 having a droplet shape (represented in black). The shell openings 34 are delimited by dams 36, that are interconnected to form the body of the shell 16. The dams 36 have side flanks 38 (represented grey) that slope gradually from a ridge 40 (represented in white) of a dyke 36 towards the opening 34. The ridge 40 have the largest thickness in the height direction h. The dams 36, in particular at the crossing points 42 thereof, also have recesses or valleys 44, surrounded by sloping flanks 46 of the ridges 40 (valleys 44 and sloping flanks 46 also represented in grey). Also side flanks 38 between adjacent dams may be grown together to form recesses 44’. The ridges 40, recesses 44, 44’, flanks 46 and side flanks 38 form a fluid jet rebounding surface 50 at the front side of the shell 16. Due to the non-(point)symmetrical shape of the openings 34 and therefore also of the dams 36 as well as the presence of the recesses 44, 44’ and flanks 46 water rebounding from the shell will be scattered in a more random way thereby improving the entanglement and thus compaction and strength of the fibrous web. The front side is indicated by reference numeral 52 and the back side by 54. Fig. 4 presents a cross section A-A’ of the hydroentanglement shell 16 of Fig. 3. Fig. 5 shows a cross section B-B’ of the hydroentanglement shell 16, perpendicular to cross section A-A’. If considered beneficial for additional dewatering, a recess may have a tiny through-hole as schematically indicated by a dotted line in the left hand dam in Fig, 4. Fig. 6 shows an embodiment of a support 60 for electroforming a hydroentanglement shell 16 as shown in Fig. 3-5. The electric conductive support 60 is provided with areas 62 (represented in black) of non-conductive material, typically a photoresist. The non-conductive areas 62 comprise areas 62a having a dumbbell shape and spots 62b. In this embodiment the areas 62 are arranged in a regular pattern. Upon electroforming, metal will initially deposit on conductive areas 64 (represented in white) of the support 60. The growth of the deposited metal will result in a network of dams having differences in orientation, angle and height of the sloping parts.. The precise sloping profile of the dams and valleys including tiny dewatering holes, if any, can be manipulated by the design of the non-conductive areas 62. The spots 62b that initially also form openings will fill with metal during the electroforming process by overgrow, but with a lower height than its surroundings, the ridges of the dams. Due to overgrowth the rod part of dumbbell shaped areas 62a will fill up, resulting in the recesses 44’ of the shell 16, which recesses 44’ separate the also resulting droplet shaped openings 34. The spots 62b are overgrown and result in the recesses 44. After sufficient deposition of metal the network body thus formed is separated from the support. Fig. 7 is a photograph of a part of a nickel hydroentanglement shell that has been manufactured by electroforming based on a design similar to Fig. 6.

In the embodiment of Fig. 8 an electroforming support 60 is provided with areas 62 of non- conductive material. The areas 62 comprise - in this embodiment randomly distributed - circular areas 62a for the shell openings to be formed and elliptical areas 62b arranged between the areas 62a. Regular patterns for the areas 62a and/or 62b are also possibilities. The longitudinal axis of the elliptical areas 62b extends in the machine direction. A hydroentanglement shell is electroformed using the support 60 as generally outlined above with respect to Fig. 6. The thus electroformed shell has circular through openings delimited by dams and narrow longitudinal recesses in the dams. The main flanks of these recesses are mainly oriented in the machine direction such that the waterjets are rebounded mainly perpendicular to the length direction of the web, thereby achieving additional entanglement in the cross direction.

Non-apertured nonwovens from viscose (1.7 dtex) were made using a hydroentanglement shell according to the invention that was electroformed from the design of Fig. 6 having an open area of 5%, respectively 8% and using a wire mesh having a mesh of 89 and open area of 22.9% at different pump pressures (= jetting pressure) of 40, 60 and 80 bar.

Fig. 9 is a diagram showing the density of these nonwovens as a function of the pump pressure.

Fig. 10 is a diagram representing the strength in the cross direction of these nonwovens as a function of the pump pressure; and Fig. 11 is a diagram showing the strength in the machine direction of the same nonwovens as a function of the pump pressure.

Tensile strength was measured according to DIN EN ISO 9073-3. As can be seen, using a hydroentanglement shell according to the invention allows to manufacture a nonwoven having a higher strength than a nonwoven made using a wire mesh in both the machine (MD) and cross direction (CD) at all pressures tested. The hydroentanglement shell according to the invention having an open area of 5% offers the best results in terms of strength.

Thus a nonwoven made according to the invention having a strength similar to a nonwoven made using a wire mesh can be manufactured at a lower water pressure, resulting in a reduced water consumption and/or energy consumption.

Claims

1. A hydroentanglement shell (16), in particular for manufacturing nonwoven fabrics, preferably a non-apertured nonwoven, by means of a web bonding process using fluid jets (20), comprising a body comprising interconnected dams (36), wherein the body has a front side (52) directed to the fluid jets during use thereof and a back side (54) opposite to the front side (52), wherein the dams (36) delimit openings (34) configured for allowing fluid to pass through from the front side (52) to the back side (54), and wherein the dams (36) have a profiled fluid jet rebounding surface (50) at the front side (52) that is configured for establishing a sideways directed rebounding effect of the fluid jet.

2. The hydroentanglement shell (16) according to claim 1, wherein the profiled fluid jet rebounding surface (50) comprises differently sloping parts (38, 40, 44, 44’, 46) at a negative angle with respect to the front side (52).

3. The hydroentanglement shell according to claim 2, wherein the differently sloping parts (38, 40, 44, 44’, 46) have slopes differing in slope direction and/or in slope angle.

4. The hydroentanglement shell according to any one of the preceding claims, wherein the profiled fluid jet rebounding surface (50) comprises recesses (44) having a height, from the back side (54) to the front side (52), that is lower than the height of ridges (40) surrounding the recesses (44).

5. The hydroentanglement shell according to claim 4, wherein the ridges (40) have flanks (46) sloping towards the recesses (44).

6. The hydroentanglement shell according to any one of the preceding claims, wherein the dams (36) have side flanks (38) sloping towards the openings (34).

7. The hydroentanglement shell according to claim 6, wherein side flanks (38) of adjacent dams (36) are connected resulting in recesses (44’)..

8. The hydroentanglement shell according to any one of the preceding claims, wherein the mouth of an opening (34) has a non-circular shape.

9. The hydroentanglement shell according to any one of claims 4 - 8, wherein the recesses (44; 44’) have an elongated shape.

10. The hydroentanglement shell according to claim 9, wherein the elongated shape extends in machine direction.

11. The hydroentanglement shell according to any one of the preceding claims, wherein the fluid jet rebounding surface (5) is configured for rebounding fluid jets mainly in a direction perpendicular to the machine direction.

12. The hydroentanglement shell according to any one of the preceding claims, wherein the openings have a longest dimension in the range of 100-450 pm, preferably 250-320 pm.

13. The hydroentanglement shell according to any one of the preceding claims, having an open area in the range of 4-10%, preferably 4.5-8.5%.

14. The hydroentanglement shell according to any one of the preceding claims, wherein the shell (16) is an electroformed metal shell.

15. The hydroentanglement shell according to claim 14, wherein the metal is nickel or a nickel alloy.

16. The shell according to any one of the preceding claims, wherein the shell (16) has a cylindrical shape.

17. An assembly (30) of a carrier (28) provided with a plurality of drainages openings and a hydroentanglement shell (16) according to any one of the preceding claims.

18. A method of manufacturing a hydroentanglement shell (16) according to any one of the preceding claims 1-16, comprising the steps of providing a support (60) having a surface provided with conductive areas (64) corresponding to the body of interconnected dams to be formed and non-conductive areas (62; 62a; 62b) corresponding to the openings to be left in the body; depositing metal on the conductive areas (64) from a solution comprising metal ions thereby forming an electroform comprising the body of interconnected dams delimiting openings, wherein the conductive areas (64) and non-conductive areas (62; 62a; 62b) are arranged and the deposition of metal is performed such that the dams in the network have a fluid jet rebounding surface comprises differently sloping parts (38, 40, 44, 44’, 46) at a negative angle with respect to the front side of the hydroentanglement shell; separating the electroform from the support.

19. The method according to claim 18, further comprising the step of growing the interconnected dams of the electroform by further deposition of metal after separating the electroform from the support.

20. A method of manufacturing a nonwoven fabric by web bonding through entanglement of fibers caused by fluid jets, comprising the steps of providing a web of fibers; jetting a fluid jet (20) on the web (12) of fibers while the web (12) is supported by a hydroentanglement shell (16) according to any one of the preceding claims 1-16 or an assembly (30) according to claim 17.