GB2568884A

GB2568884A - A stretchable tubular elastic article

Info

Publication number: GB2568884A
Application number: GB1719733.6A
Authority: GB
Inventors: Stephen Cain Miles
Original assignee: Stretchline Intellectual Properties Ltd Virgin Islands
Current assignee: Stretchline Intellectual Properties Ltd Virgin Islands
Priority date: 2017-11-28
Filing date: 2017-11-28
Publication date: 2019-06-05
Also published as: GB201719733D0

Abstract

A stretchable tubular elastic article, such as, for example, a compression garment, a support bandage or a wound dressing, and a method of forming a stretchable tubular elastic article. The article (10, fig 1) comprising a network of strands (12, fig 1) of cured elastomer arranged to define a hollow, tubular structure. The network of strands (12) may include at least one strand (14, fig 1) of cured elastomer arranged to define a series of successive turns 60, 62 in a coil and at least one strand of cured elastomer (18, fig 1) arranged to transect the turns, the strands of cured elastomer being fused at each point of transection (20). The method of forming the article comprises the steps of: extruding at least one strand of liquid elastomer around a tubular support so as to form a series of successive turns in a coil; extruding at least one strand of liquid elastomer so as to transect the successive turns; and curing or otherwise allowing the liquid elastomer to set and solidify so as to form a network of strands defining a hollow, tubular structure in which the strands of cured elastomer are fused at each point of transection. Apparatus 50, which may include a tubular support 52 mounted for rotational and translational movement relative to an extrusion head 54 of an extrusion unit 56. Apparatus 50 may include a controller to control rotational and translational movement of the tubular support relative to the extrusion head. The cured elastomer may be a silicone rubber compound. The article may include an additive embedded in the network of strands of cured elastomer, such as one or more of a perfume, a scent, a colour, decorative particles and an anti-microbial agent.

Description

A STRETCHABLE TUBULAR ELASTIC ARTICLE

The invention relates to a stretchable tubular elastic article, such as, for example, a compression garment, a support bandage or a wound dressing, and a method of forming a stretchable tubular elastic article.

According to a first aspect of the invention there is provided a stretchable tubular elastic article comprising a network of strands of cured elastomer arranged to define a hollow tubular structure.

The use of a cured elastomer results in a network of strands that is capable of exhibiting stretch. The stretchability of the network of strands allows the stretchable tubular elastic article to stretch about a wearer or other item requiring support and/or compression. This, in turn, allows the stretchable tubular elastic article to modify its shape so as to provide a snug fit.

The use of a network of strands of cured elastomer to form a stretchable tubular elastic article results in the creation of an open structure and thus a support or compression member that is breathable and can readily be cleaned before and after use.

This is particularly beneficial in sports and medical applications. The stretchable tubular elastic article may, for example, be used as a knee support or a support for other muscles and/or joints. In other embodiments it may be used, for example, as a compressive stocking to prevent the formation of a thrombosis following surgery or during a long-haul flight. In yet further embodiments it may be used in order to hold a wound dressing in position.

It is also envisaged that the stretchable tubular elastic article may be used in other applications requiring tubular support and/or compression. The stretchable tubular elastic article may, for example, be used to wrap and maintain rolls of foodstuffs, including meat.

The network of strands may include at least one strand of cured elastomer arranged to define a series of successive turns in a coil and at least one strand of cured elastomer arranged to transect the turns, the strands of cured elastomer being fused at each point of transection.

The use of a series of successive turns in a coil results in a uniform structure that creates a constant force when it is used to apply support or a compressive force. The provision of at least one strand arranged to transect the turns maintains the positions of the turns relative to each other so as to ensure a consistent supportive and/or compressive force applied, in use, by the stretchable tubular elastic article.

In such embodiments, the relative positions of the series of successive turns in the coil may be enhanced by arranging the at least one strand of cured elastomer to transect the successive turns of the coil at spaced locations about the circumference of the turns.

In preferred embodiments, the network of strands may include at least one strand of cured elastomer arranged to define a first helical coil of successive turns coiled in a first direction and at least one strand of cured elastomer arranged to define a second helical coil of successive turns coiled in a second direction, the second direction being opposite to the first direction and the second helical coil being arranged to overlie the first helical coil so that the turns of the second helical soil transect the turns of the first helical coil.

The transection and fusing of the turns of the first and second helical coils ensures a uniform and consistent application of a supportive and/or compressive force whilst ensuring stability and strength within the structure of the stretchable tubular elastic article itself.

In particularly preferred embodiments the network of strands may include a plurality of layers, each layer including at least one strand arranged to define a helical coil of successive turns, the helical coil of adjacent layers being alternately coiled in the first and second directions so that the turns of the helical coil of each successive layer transects the turns of the helical coil of the previous layer.

The use of a multi-layered structure in which the turns of the helical coil of successive layers are laid over and across each other results in an open network of fused strands having openings between the fused strands.

The tubular structure in such embodiments may exhibit depth, breathability, power, strength, compressibility and an ability to dissipate impact forces. It is envisaged, for example, that the compressibility and ability to dissipate impact forces could render the stretchable tubular elastic article suitable for use in the creation of protective clothing to protect a wearer against projectile such as bullets or other debris that a wearer might encounter in a hazardous workplace. It is envisaged that the stretchable tubular elastic article may, for example, be used to create an arm or leg of a protective garment. In other embodiments, the stretchable tubular elastic article may be used to create protective knee pads or elbow pads for use in work or sporting environments. The compressibility of the multi-layered structure and the ability of the network of strands to dissipate impact forces allows the stretchable tubular elastic article to absorb the force of an impact as opposed to transmitting the force to a wearer.

It is also envisaged that through an appropriate choice of cured elastomer, the stretchable tubular elastic article could be used as a grip for a tennis racquet, golf club, a bike handlebar or other piece of sports equipment.

Preferably, the coils of alternate layers are also offset relative to each other so that the openings formed between a pair of adjacent layers are offset relative to the openings formed between the next pair of adjacent layers. This results in the creation of tortuous paths through the solidified network of strands.

The creation of tortuous paths allows the flow of air and moisture through the structure and thus provides ventilation and allows moistures to escape, and thus allows the structure to breathe.

The use of a cured elastomer results in an open structure that is compressible whilst defining an otherwise strong and powerful structure.

So as to create varying effects in use, the different layers of the network of strands may be selected to exhibit different degrees of stretch and/or power and/or compressibility. Less material may, for example, be used in regions where less stretch is required from the stretchable tubular elastic article. This may be achieved by increasing the spacing between successive turns in the helical coil of each layer and/or by changing the diameter of the or each strand used in each layer.

Variations in the degrees of stretch and/or power and/or compressibility may, in addition, or alternatively, be achieved through the use of different elastomers for different layers or different sections of different layers.

The elastomer may be a thermoset material chosen from the group consisting of silicone and acrylic and, in particularly preferred embodiments, the elastomer is a silicone rubber compound. The use of a silicone rubber compound results in a structure that is strong, resilient and stretchable depending on the Shore hardness of the particular silicone rubber compound used. For applications requiring less stretch and relatively high strength, Momentive’s LSR 2650 silicone rubber may be used. For applications requiring more stretch and less strength, Momentive’s RTV 835 may be used.

In order to create a cushioning effect on an inner surface of the stretchable tubular elastic article, the innermost layer of the network of strands may be formed from a cured silicone gel.

In embodiments of the invention, an outer surface of the network of strands may be patterned. Such patterning might provide a decorative effect or branding.

In further embodiments, the stretchable tubular elastic article may further include an additive embedded in the network of strands of cured elastomer. Such an additive may include one or more chosen from the group consisting of a perfume, a scent, a colour, decorative articles and an anti-microbial agent.

According to a second aspect of the invention there is a provided a method of forming a stretchable tubular elastic article comprising the steps of:

(i) extruding at least one strand of liquid elastomer around a tubular support so as to form a series of successive turns in a coil;

(ii) extruding at least one strand of liquid elastomer so as to transect the successive turns; and (iii) curing or otherwise allowing the liquid elastomer to set and solidify so as to form a network of strands defining a hollow, tubular structure in which the strands of cured elastomer are fused at each point of transection.

The manner in which the strands of liquid elastomer are extruded onto the tubular support prior to curing results in the creation of a solidified network of strands that inevitably includes openings and is therefore breathable in use in the sense that it allows the throughflow of air.

So as to facilitate extrusion of the liquid elastomer about the tubular support, the method preferably includes mounting the tubular support for rotational and translational movement of the tubular support relative to an extrusion head of an extrusion unit for extruding liquid elastomer onto the tubular support, and controlling rotational and translational movement of the tubular support during extrusion of liquid elastomer onto the tubular support so as to perform steps (i) and (ii).

In particularly preferred embodiments, step (i) further includes extruding the at least one strand of liquid elastomer around the tubular support in a first direction so as to form a first helical coil of successive turns wound around the tubular support, and step (ii) further includes extruding the at least one strand of liquid elastomer around the tubular support in a second, opposite direction over the first helical coil so as to form a second helical coil of successive turns wound around the tubular support in an opposite direction to the first helical coil.

So as to tailor the strength and/or stretchability and/or compressibility of the resultant stretchable tubular elastic article, steps (i) and (ii) may further include controlling the rate of extrusion of liquid elastomer to vary the amount of liquid elastomer extruded during the formation of each layer. Less material may, for example, be used in regions where less stretch is required from the stretchable tubular elastic article.

By controlling the rate of extrusion of liquid elastomer during extrusion, it is possible to vary the amount of liquid elastomer for an entire helical coil of a layer or for a discrete section of a helical coil.

In addition, or alternatively, so as to tailor the strength and/or stretchability and/or compressibility of the resultant stretchable tubular elastic article rotational and/or translational movement of the tubular support may be controlled during extrusion of liquid elastomer onto the tubular support so as to control the density of coils extruded onto the tubular support.

This allows, for example, the creation of a stretchable tubular elastic article having varying degrees of compressibility. This could be particularly advantageous in the creation of a compression garment requiring localised areas of high compression. The compressive effect created by compression hosiery is by necessity non-uniform, greater compression being required in an ankle region and less compression being required in the calf region.

Variations in the strength and/or stretchability and/or compressibility of the resultant stretchable tubular elastic article may also be created through the use of different liquid elastomers to form different layers of the multi-layered network of strands or to create sections of one or more layers of the multi-layered network of strands.

As outlined above in connection with the first aspect of the invention, the elastomer may be a thermoset material chosen from the group consisting of silicone and acrylic and, in particularly preferred embodiments, the elastomer is a silicone rubber compound. The use of a silicone rubber compound results in a structure that is strong, resilient and stretchable depending on the Shore hardness of the particular silicone rubber compound used. For applications requiring less stretch and relatively high strength, a two-component liquid silicone rubber consisting of A and B components and produced by Momentive under reference LSR 2650 and mixed in a ratio of A:B of 40:60 may be used. For applications requiring more stretch and less strength, Momentive’s RTV 835 may be used.

In order to create a cushioning effect on an inner surface of the stretchable tubular elastic article, a first performance of step (i) may include extruding a liquid silicone gel onto the tubular support to form a lowermost layer of the multi-layered structure.

Following curing, a silicone gel creates a relative soft cushioning layer that improves comfort when the cushioning layer is pressed against a wearer’s body. This is particularly advantageous in the field of support bandages, compression garments and wound dressings.

In embodiments of the invention, an outer surface of the tubular support may be etched to define a negative of the patterning required. In such embodiments, the method further includes the step of turning the hollow, tubular structure inside out following completion of step (iii) so as to present a patterned outer surface on the network of strands replicating the pattern etched onto the tubular support.

This methodology allows the creation of a stretchable tubular elastic article having a pattern embedded in the outermost layer. This pattern could include a decorative effect and/or could include branding.

So as to produce decorative or functional elements, one or more additives may be mixed with the liquid elastomer before curing thereof. Doing so ensures that the additive remains embedded in the elastomer following curing.

Depending on the nature of the additive, the additive may be introduced into the liquid elastomer before or after extrusion of the liquid elastomer. Larger additives that cannot readily be dispensed via an extrusion head in mixture with the liquid elastomer or those requiring a specific position and/or orientation in the stretchable tubular elastic article may be introduced following extrusion and prior to curing.

Mixing the additive prior to extrusion, however, is advantageous in circumstances where the nature of the additive allows in that is ensures a homogeneous mix of the additive in the liquid elastomer before extrusion. It is, therefore, particularly advantageous when the additive is chosen from a group consisting of a perfume, a scent, a colour, decorative articles and an anti-microbial agent.

The term decorative particles is intended to refer to particles that produce a visual effect such as glitter particles, metallic particles, glass particles and coloured particles.

In other embodiments, the additive may include a coloured pigment suspended in a silicone oil so as to colour the liquid elastomer.

In yet further embodiments, the method may further include the step of spraying the network of strands with an anti-microbial agent.

In order to create a predetermined finish on the surface of the network of strands, the method may further include the step of spraying the network of strands with a top coat.

The provision of a top coat can advantageously be used to provide a matt and non-tacky finish and therefore further improves the handling of the resultant network of strands which could otherwise have a tacky surface as a result of the elastomer used in the method.

In a particularly preferred embodiment, the top coat may be a two-component liquid silicone rubber consisting of A and B components and produced by Momentive under the reference LSR top-coat HE and mixed in a ratio A:B of 50:50.

It will again be appreciated that other liquid silicone rubbers could be used as a top coat depending on the physical properties required of the stretchable tubular elastic article. Similarly the ration of A:B of the component parts of Momentive’s LSR top coat HE may be varied to produce a network of strands having different physical properties.

Curing of the liquid elastomer may be achieved through heating or through exposure to electromagnetic radiation, such as ultraviolet radiation or a laser.

Embodiments of the invention will now be described, by way of non-limiting examples, in which:

Figure 1 shows a stretchable tubular elastic article according to a first embodiment of the invention;

Figure 2 shows a stretchable tubular elastic article according to a second embodiment of the invention; and

Figures 3a and 3b illustrate a method of forming the stretchable tubular elastic article shown in Figure 2.

A stretchable tubular elastic artic 10 according to a first embodiment of the invention is shown in Figure 1.

The stretchable tubular elastic article 10 includes a network of strands 12 of cured elastomer arranged to define a hollow tubular structure.

The network of strands 12 includes a strand 14 of cured elastomer arranged to define a series of successive turns 16 in a coil. The network of strands 12 also includes a plurality of strands 18 of cured elastomer arranged to transect the turns 16 at equidistantly spaced positions about the circumference of the turns 16. The strands 14,18 are fused at each point of transection 20.

The series of successive turns 16 create a uniform structure that creates a constant force when it is used to apply support or a compressive force. The provision of the strands 18 transecting the turns 16 maintains the positions of the turns 16 relative to each other so as to ensure a consistent supportive and/or compressive force applied by the stretchable tubular elastic article 10.

Referring to Figure 1, it can be seen that the turns 16 are densely packed relative to each other. Such an arrangement creates a strong and effective compressive force when the stretchable tubular elastic article 10 is worn, for example, by a user as a support bandage.

In other embodiments, the diameter of the strand 14 forming the turns 16 may be increased and the spacing between adjacent turns 16 may be increased in order to vary the effect created by the stretchable tubular elastic article 10 in use.

The cured elastomer used to form the strands 14,18 is Momentive’s LSR 2650, which is a silicone rubber having a relatively high Shore hardness. In other embodiments requiring more stretch and less strength, Momentive’s RTV 835 may be used. This is a silicone rubber having a relatively low Shore hardness.

A stretchable tubular elastic article 30 according to a second embodiment of the invention is shown in Figure 2.

The stretchable tubular elastic article 30 includes a network of strands 32 of cured elastomer arranged to define a hollow tubular structure.

The network of strands 32 includes a strand 34 arranged to define a first helical coil of successive turns 36 coiled in a first direction. The network of strands 32 also includes a strand 38 (shown in broken lines) arranged to define a second helical coil of successive turns 40 coiled in an opposite direction to the turns 36 of the first helical coil. Referring to Figure 2, it can be seen that strand 38 is wound in a clockwise direction to form turns 40 whereas strand 34 is wound in an anti-clockwise direction to form turns 36.

The second helical coil is arranged to overlie the second helical coil so that the turns 40 of the second helical coil transect the turns 36. The strands 34,38 are fused at each point of transection 42.

As with the stretchable tubular elastic article 10 shown in Figure 1, the cured elastomer used to form strands 34,38 is Momentive’s LSR 2650.

The stretchable tubular elastic articles 10,30 shown in Figures 1 and 2 may each include an additive embedded in the cured elastomer. The additive may include one or more from the group consisting of a perfume, a scent, a colour, decorative particles and an antimicrobial agent.

A method of forming a stretchable tubular elastic article will now be described with reference to the apparatus 50 shown in Figures 3a and 3b which includes a tubular support 52 mounted for rotational and translational movement relative to an extrusion head 54 of an extrusion unit 56.

The apparatus 50 includes a controller (not shown) to control rotational and translational movement of the tubular support 52 relative to the extrusion head 54.

The extrusion head 54 is connected to a reservoir in which components A and B of Momentive’s silicone rubber LSR 2650 is mixed in a ratio of A:B of 40:60.

During operation of the apparatus 50, the extrusion head 54 extrudes a strand 58 of liquid silicone rubber onto tubular support 52 whilst the tubular support 52 rotates relative to the extrusion head 54. The tubular support 52 also translates relative to the extrusion head 54 in the direction of arrow A. This results in the creation of a first helical coil of successive turns 60 wound around the tubular support 52.

On completion of the first helical coil of successive turns 60, the tubular support 52 continues to rotate relative to the extrusion head 54 but translates relative to the extrusion head 54 in an opposite direction, in the direction of arrow B (Figure 3b). This results in the creation of a second helical coil of successive turns 62 wound round the tubular support 52 in an opposite direction to the first helical coil.

It will be appreciated that rotation and translation of the tubular support 52 relative to the extrusion head 54 may be repeated to form a multi-layered network of strands. In such embodiments, the helical coils of adjacent layers are alternately coiled in the first and second directions about the tubular support 52 so that the turns of the helical coil of each successive layer transects the turns of the helical coil of the previous layer.

In such embodiments, it is envisaged that the starting position of the tubular support 52 relative to the extrusion head 54 may be offset in the direction of arrows A and B respectively so as to offset the turns 60,62 of the resultant pair of helical coils relative to the turns 60,62 of the previous pair of helical coils.

In another embodiment, rotation of the tubular support 52 may be stopped on completion of the first helical coil of successive turns 60 and the tubular support 52 may instead be translated in the direction of arrow B so as to allow the creation of a relatively straight strand of liquid silicone rubber transecting the turns 60 of the first helical coil as per the arrangement shown in Figure 1. The tubular support 52 may then be rotated a predetermined distance before translating in the direction of arrow A so as to allow the creation of a further, relatively straight strand of liquid silicone rubber transecting the turns 60 of the first helical coil.

It will be appreciated that in such an embodiment, rotation and translation of the tubular support 52 relative to the extrusion head 54 is repeated until the required number of strands transecting the successive turns 60 of the first helical coil have been completed.

Following completion of the extrusion steps, the liquid silicone rubber is heated by means of a heat lamp (not shown) in order to cure the liquid silicone rubber so as to form a network of strands defining a hollow, tubular structure in which the strands of cured silicone are fused at each point of transection.

It is envisaged that, in other embodiments of the invention, a different liquid elastomer may be used. Depending on the liquid elastomer selected, curing of the liquid elastomer may be achieved through exposure to electromagnetic radiation, such as ultraviolet radiation.

It is also envisaged that, in other embodiments of the invention, the liquid elastomer may 15 be selected such that resultant strands of liquid elastomer are capable of setting and solidifying so as to form the network of strands.

Claims

1. A stretchable tubular elastic article comprising a network of strands of cured elastomer arranged to define a hollow, tubular structure.

2. A stretchable tubular elastic article according to Claim 1 wherein the network of strands includes at least one strand of cured elastomer arranged to define a series of successive turns in a coil and at least one strand of cured elastomer arranged to transect the turns, the strands of cured elastomer being fused at each point of transection.

3. A stretchable tubular elastic article according to Claim 2 wherein the network of strands includes at least one strand of cured elastomer arranged to define a first helical coil of successive turns coiled in a first direction and at least one strand of cured elastomer arranged to define a second helical coil of successive turns coiled in a second direction, the second direction being opposite to the first direction and the second helical coil being arranged to overlie the first helical coil so that the turns of the second helical coil transect the turns of the first helical coil.

4. A stretchable tubular elastic article according to Claim 3 wherein the network of strands includes a plurality of layers, each layer including at least one strand arranged to define a helical coil of successive turns, the helical coils of adjacent layers being alternately coiled in the first and second directions so that the turns of the helical coil of each successive layer transects the turns of the helical coil of the previous layer.

5. A stretchable tubular elastic article according to Claim 4 wherein different layers of the network of strands exhibit different degrees of stretch and/or power.

6. A stretchable tubular elastic article according to Claim 4 or Claim 5 wherein different layers of the network of strands are formed from different cured elastomers.

7. A stretchable tubular elastic article according to any one of Claims 4 to 6 wherein the cured elastomer is a silicone rubber compound.

8. A stretchable tubular elastic article according to any one of Claims 4 to 7 wherein an innermost layer of the network of strands is formed from a cured silicone gel.

9. A stretchable tubular elastic article according to any one of the preceding claims wherein an outer surface of the network of strands is patterned.

10. A stretchable tubular elastic article according to any one of the preceding claims further including an additive embedded in the network of strands of cured elastomer.

11. A stretchable tubular elastic article according to Claim 10 wherein the additive includes one or more chosen from the group consisting of a perfume, a scent, a colour, decorative particles and an anti-microbial agent.

12. A compression garment comprising a stretchable tubular elastic article according to any one of the preceding claims.

13. A support bandage comprising a stretchable tubular elastic article according to any one of Claims 1 to 11.

14. A wound dressing comprising a stretchable tubular elastic article according to any one of Claims 1 to 11.

15. A method of forming a stretchable tubular elastic article comprising the steps of:

16. A method of forming a stretchable tubular elastic article according to Claim 15 wherein the method includes mounting the tubular support for rotational and translational movement thereof relative to an extrusion head of an extrusion unit for extruding liquid elastomer onto the tubular support, and controlling rotational and translational movement of the tubular support during extrusion of liquid elastomer onto the tubular support so as to perform steps (i) and (ii).

17. A method of forming a stretchable tubular elastic article according to Claim 15 or Claim 16 wherein:

step (i) further includes extruding the at least one strand of liquid elastomer around the tubular support in a first direction so as to form a first helical coil of successive turns wound around the tubular support; and step (ii) further includes extruding the at least one strand of liquid elastomer around the tubular support in a second, opposite direction over the first helical coil so as to form a second helical coil of successive turns wound around the tubular support in an opposite direction to the first helical coil.

18. A method of forming a stretchable tubular elastic article according to Claim 17 wherein steps (i) and (ii) are repeated to form a multi-layered network of strands, the helical coils of adjacent layers being alternately coiled in the first and second directions so that the turns of the helical coil of each successive layer transects the turns of the helical coil of the previous layer.

19. A method of forming a stretchable tubular elastic article according to any one of Claims 15 to 18 wherein steps (i) and (ii) further include controlling the rate of extrusion of liquid elastomer to vary the amount of liquid elastomer extruded during the formation of each layer.

20. A method of forming a stretchable tubular elastic article according to Claim 16 or any claim dependent thereon wherein rotational and/or translational movement of the tubular support is controlled during extrusion of liquid elastomer onto the tubular support so as to control the density of coils extruded onto the tubular support.

21. A method of forming a stretchable tubular elastic article according to Claim 18 or any claim dependent thereon wherein different liquid elastomers are used to form different layers of the multi-layered network of strands.

22. A method of forming a stretchable tubular elastic article according to any one of Claims 15 to 21 wherein the liquid elastomer is a silicone rubber compound.

23. A method of forming a stretchable tubular elastic article according to Claim 18 or any claim dependent thereon wherein a first performance of step (i) includes extruding a liquid silicone gel onto the tubular support to form a lowermost layer of the multi-layered structure.

24. A method of forming a stretchable tubular elastic article according to any one of Claims 15 to 23 wherein an outer surface of the tubular support is etched to define a pattern and the method further includes the step of turning the hollow, tubular structure inside out following completion of step (iii) so as to present a patterned outer surface on the network

5 of strands replicating the pattern etched onto the tubular support.

25. A method of forming a stretchable tubular elastic article according to any one of Claims 15 to 24 further including the step of introducing an additive into the liquid elastomer before curing thereof.

26. A method of forming a stretchable tubular elastic article according to Claim 25 wherein the additive is introduced into the liquid elastomer before extrusion thereof.

27. A method of forming a stretchable tubular elastic article according to Claim 25 or 15 Claim 26 wherein the additive includes one or more chosen from the group consisting of a perfume, a scent, a colour, decorative particles and an anti-microbial agent.