EP3989762B1

EP3989762B1 - Cooling garment

Info

Publication number: EP3989762B1
Application number: EP20736799.6A
Authority: EP
Inventors: Johannes Ijsbrand Tiesnitsch
Original assignee: TIESNITSCH BEHEER BV
Current assignee: TIESNITSCH BEHEER BV
Priority date: 2019-06-25
Filing date: 2020-06-25
Publication date: 2023-10-25
Anticipated expiration: 2040-06-25
Also published as: AU2020307273A1; CN114173595A; NL2023381B1; US20220338567A1; KR20220018067A; JP2022540775A; EP3989762A1; WO2020263090A1

Description

The invention relates to a cooling garment for cooling a torso of a wearer.
People and animals may bring down their body temperature by the evaporation of water on their skin - water that is excreted by themselves in the form of sweat. This principle of evaporative cooling may also be used in technical means to support the natural cooling of a body, for example in cooling garments. The water is then contained in the garment by a suitable water-absorbing substance, such as cellulose or a super absorbent polymer of the type that is present in diapers and feminine napkins. The latter are known to be capable of holding up to 300 times their weight of water.
The water-absorbing substance is typically sandwiched between two outer layers of the fabric that constitutes the garment. Such layers are permeable to water (as a liquid and/or vapor), which allows the transport of water from the water-absorbing substance to the outer surface of the garment. Upon evaporation of the water, heat is withdrawn from the garment, which manifests as a cooling effect.
For example, US 2014/318154 describes a cooling garment for cooling a torso of a wearer, comprising a front and a rear panel with a neck opening there between. A cooling section with an inlet for water is provided on the front and rear panel.
For example, WO 2012/156067 A1 describes a cooling garment wherein the two outer layers are water-permeable. When such garment is contacted with water (e.g. by submerging), the water-absorbing substance in the garment absorbs the water through the outer layers. This activates the garment and makes it ready for use.
A disadvantage of outer layers that are water-permeable is that their surface at the interface with air becomes humid during use of the garment, because the water absorbed in the inside reaches the outer surface as a liquid. This is especially the case when the garment is subjected to pressure, for example during wearing of the garment. The humid surface is often experienced as uncomfortable by the wearer of such garment. On the other hand, when the outer layers are impermeable to liquid water, activation by simply immersing the garment in water is not possible anymore.
It is therefore an objective of the invention to provide a cooling garment wherein the surface of the garment does not become humid during use of the garment. It is also an objective that such garment can easily be activated, i.e. wherein the feeding of water to the water-absorbing substance is convenient and reproducible.
It has now been found that these objectives can be reached by a cooling garment for cooling a torso of a wearer, comprising a front and a rear panel with a neck opening therebetween, wherein

the front panel and the rear panel comprise one single cooling section that forms at least a portion of the front panel and at least a portion of the rear panel, the cooling section comprising
- ∘ a neck opening that coincides with the neck opening of the cooling garment, the neck opening (5) defining a neck opening surface area (SA_{neck opening});
- ∘ a cooling surface area (SA_cooling);
- ∘ a circumferential edge and a neck edge;
the cooling section is made of a cooling material comprising
- ∘ two outer layers that are impermeable to liquid water, at least one of the outer layers being permeable to water vapor;
- ∘ a water absorbent layer that is enclosed between both outer layers;
the two outer layers are sealed together along the circumferential edge and the neck edge to form a single compartment for the storage of water, the compartment having a first portion at the front panel and a second portion at the rear panel, both portions being in fluid communication with one another;
the compartment comprises an inlet for water.

Figure 1 displays a top view of a first cooling garment according to the invention, spread on a flat surface.
Figure 2 displays a top view of a second cooling garment according to the invention, spread on a flat surface.
Figure 3 displays a top view of a third cooling garment according to the invention, spread on a flat surface.

Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various exemplary embodiments of the present invention. Furthermore, the terms "first", "second", and the like herein, if any, are generally used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order.
The front panel and the rear panel of a cooling garment of the invention together form one piece with a neck opening between both panels. When a cooling garment of the invention is worn by a person, the garment is put around the person's neck so that the neck opening is present around the neck and the garment rests on the person's shoulders. The front panel of the garment then extends over the person's chest and the rear panel over the person's back. The cooling section of the garment constitutes that part of the garment that has the actual cooling capacity. It is also in one piece and comprises the neck opening of the garment. A first portion of the cooling section is present at the front panel of the cooling garment and a second portion of the cooling section is present at the rear panel of the cooling garment. The cooling section preferably does not reach to the waist of the wearer, but is more or less limited to the rib cage of the wearer. This is because cooling of the belly and of organs such as the kidneys and the stomach is usually felt as uncomfortable. Nevertheless, the front panel and the rear panel of the cooling garment itself may well reach to the waist of the wearer. This is realized by connecting a (conventional) fabric to the cooling section that lacks cooling capacity, so that the front and/or the rear panel is partly formed by the cooling section and partly by the non-cooling fabric.
A cooling garment of the invention may comprise holes for body parts other than the neck, such as the arms. The cooling section itself, however, only contains a hole for the neck (the neck opening) and no holes for other body parts (as discussed below, the cooling section optionally comprises additional holes for ventilation (vent holes), but these are not suitable for accommodating body parts such as arms during wearing of the garment). Having no arm openings, the cooling section does not extend from the front panel to the rear panel under the arms of the wearer. As a result, the cooling section comprises one continuous circumferential edge at the contours of the cooling section. The only other edges of the cooling section are edges that define holes in the cooling section. In particular, the neck opening comprises a neck edge, and the optional vent holes comprise vent hole edges.
The cooling section comprises a compartment for the storage of water - the water that provides the cooling upon evaporation. The compartment is formed by two outer layers that are impermeable to liquid water, while at least one of the outer layers is permeable to water vapor. Both layers are sealed together at their edges, so that the compartment is formed. The edges along which the layers are sealed, are the circumferential edge and the edges of one or more openings that are present in both layers, i.e. those of the neck opening and of the optional vent holes. The sealing of the edges brings along that a particular surface area of the outer layer is not available for the transmission of water vapor, because that part of the surface area is connected to the opposing outer layer and does therefore not enclose the compartment. This so-called "seal surface area" (SA_seals) is thus a part of the surface of the cooling section that lacks a cooling capacity. A sealed edge of the cooling section typically has a width in the range of 1-10 mm, in particular in the range of 2-5 mm.
The neck opening is formed by a hole in each layer, wherein both holes are positioned such that they align upon sealing of both layers. The same accounts for the vent holes that are optionally present in the cooling section.
As introduced above, the cooling section in a garment of the invention may comprise vent holes. These are holes through which a fluid may pass, wherein

the vent holes are defined by coinciding vent hole edges of the two layers;
the outer layers are sealed together along the vent hole edges to form a seal around each vent hole having a seal surface area (SA_{vent hole seal});
the vent holes define an open surface area (SA_{vent holes}).

In the present application, the term fluid is used to indicate a phase of matter that includes liquids and gases. The fluid that typically passes through the vent holes when an activated garment of the invention is worn is air with evaporated sweat. Each vent hole is a window with a particular surface area - all vent holes together define the total area of a cooling section that is available for the passage of a fluid. For the present invention, this total area is termed the "vent hole surface area" (SA_{vent holes}) of the cooling section of a cooling garment. Further, the neck opening is also a window with a particular surface area. This area is termed the "neck opening surface area" (SA_{neck opening}).
The cooling section comprises a "cooling surface area" (SA_cooling). This is the surface area of the cooling section that is capable of cooling, i.e. that has a cooling capacity. This surface area is formed by that part of the surface of the outer layer(s) that is capable of transmitting water vapor from the compartment to the atmosphere outside the compartment. Accordingly, the neck opening, the seal surface areas and the vent holes of the cooling device are not a part of the cooling surface area (SA_cooling).
The relation between the cooling surface area (SA_cooling) and the other surface areas explained above may also be expressed in the form of the following formula (I) ${SA}_{cooling} = {SA}_{cooling section} - {SA}_{open} - {SA}_{seals}$
wherein:

1) SA_{cooling section} is defined as the surface of the cooling section as a whole, not taking into account any discontinuities such as holes and openings;
2) SA_open = SA_{neck opening} + SA_{vent holes};
3) SA_seal = SA_{circumferential seal} + SA_{neck seal} + SA_{vent hole seal}.

The cooling surface area (SA_cooling) refers only to the surface of the outer layer that faces the atmosphere outside the compartment; it does not include the surface of the outer layer that faces the torso of the wearer.
Between both outer layers is sandwiched a layer of a water absorbent material (a water absorbent layer). This layer prevents the sagging of the water to the lowest parts of the compartment and brings about an even distribution of the water in the cooling section. In addition, the layer effectively replenishes areas in the compartment where water has been evaporated by sucking up water and transporting water from other areas. To this end, the water absorbent material is preferably a superabsorbent polymer.
As described above, the water absorbent layer is present between both outer layers. The water absorbent layer may be present everywhere between both outer layers, including in the seal. It is also possible, however, that it is excluded from the seals. This means that it is only present in the actual compartment for the storage of water.
Where the absorbent layer is included in the seal (co-sealed), the water absorption capacity is virtually lost. Moreover, especially when the seal is made by heat-sealing, both outer layers have essentially lost their permeability to water vapor. So, sealed areas do not provide a significant cooling capacity even if they comprise the absorbent layer.
When the water absorbent layer is not in the seal, it has to be shaped such that is only present in the compartment for the storage of water. This can during the production of the cooling garment e.g. be accomplished by excising from the water absorbent layer all locations where a seal is to be made. Since the excising needs to be performed with a safety margin to accommodate for the tolerances of the production process (such as the tolerances of where a seal is to be made), the overall amount of water absorbent material per unit of cooling surface area (SA_cooling) is lower than when the water absorbent layer would be included in the seal (because in the latter case, the water absorbent layer is present on locations where it would not be otherwise because of the safety margin). So, there is a loss of water absorbent capacity. Compensation of this loss by e.g. providing a thicker water absorbent layer is not desired because this results in a larger surface relief of the cooling garment.
A loss of water absorbent capacity makes that the water in the compartment is more susceptible to gravity-induced accumulation in lower parts of the cooling section when the cooling garment is worn by a person. When pressure is exerted on those locations of the cooling section where water has accumulated (e.g. when the person wearing the garment sits with the back (i.e. the rear panel) to the back of a chair), the seals may succumb or break down. Thus, sealing of the water absorbent layer between the outer layers decreases the chance on failure of the seal.
Another effect of the reduction of water absorbent material per unit of cooling surface area (SA_cooling) is a loss of cooling capacity because the effective cooling surface area itself is also decreased. After all, the outer layers are not backed by the water absorbent layer at the locations of the safety margins along the seals, leading to a decrease of the effective cooling surface area. Compensation of this loss in cooling capacity by e.g. providing a thicker water absorbent layer is not effective, because this does not increase the effective cooling surface (the safety margins along the seal(s) are still void of water absorbent material).
Another important effect manifests when vent holes are present in the cooling section. Their presence is accompanied with a substantial increase of seal surface area (SA_{vent hole seal}), making the total surface of water absorbent layer that is lost to the safety margins disproportionately higher.
Another advantage of including the water absorbent layer in the seal (co-sealing) is that the water absorbent layer itself remains in place. When the edges of the water absorbent layer are contained in the seal, then its lateral movement relative to the outer layers is severely restricted. It will e.g. not be allowed to fold inside the compartment formed by the two outer layers, which can ultimately lead to accumulation of the water absorbent material in certain areas of the compartment. The fixation of the water absorbent layer also prevents the layer from sagging to the bottom of the compartment due to gravity, which may in particular happen when the layer is (highly) charged with water. Thus, the problem of a free-lying water absorbent layer is that it is prone to folding, accumulation and/or sagging. This will not occur in a cooling garment of the invention which has the water absorbent layer co-sealed with the two outer layers.
Yet another problem of a free-lying (i.e. non-fixated) water absorbent layer is that its edges may well bridge the safety margin and so reach the seals, e.g. when the cooling garment is worn by a person, especially when the person moves his/her body. Repeated contact between the water absorbent layer and the seal may result in abrasion of one or both outer layers and ultimately in a leak so that liquid water seeps out of the cooling section. This problem with a non-fixated water absorbent layer occurs in the absence but also in presence of the safety margin discussed above. Fixation of the water absorbent layer in the seal solves this problem as it prevents such abrasion and leakage.
Preferably, the entire cooling surface area (SA_cooling) is lined with the water absorbent layer. In this way, the entire cooling surface area (SA_cooling) of the cooling device can be used to transmit the evaporated water, i.e. the cooling garment has the highest cooling capacity. In practice, as is elaborated above, it may also be that the water absorbent layer does not abut the edges that are sealed together, but stays a small distance away a from them (a safety margin), e.g. a few millimeters. The disadvantages of such embodiments are outlined above.
As already mentioned above, a first part of the cooling section is present at the front panel and a second part of the cooling section is present at the rear panel of the cooling garment. The same accounts for the compartment of the cooling section, which inherently means that the part of the compartment that is present at the front panel is in fluid communication with the part of the compartment that is present at the rear panel. Since the compartment does not extend below the armpits (i.e. it does not extend around the ribcage of the torso), the fluid communication occurs over one or both shoulders (i.e. along both sides of the neck opening). It is highly preferred, however, that there is fluid communication over both shoulders. In the present application, by fluid communication is meant that different parts or areas of the cooling section are connected to each other or are in proximity with each other to hold or be surrounded by the same fluid.
An important advantage of fluid communication over both shoulders is that it allows cooling at both shoulders, which cooling then essentially occurs all around the neck (in addition to that provided on e.g. the chest). When the water absorbent layer is present in the entire compartment, including directly around the neck opening (and preferably sealed together with the neck seal), muscles and blood vessels of the wearer that run from the shoulder and the chest to the neck are comfortably cooled. A particular advantage is that the carotid artery is also cooled in this way. Cooling of tissues at and around the neck is not only important for controlling the temperature in the wearer's neck and head, but it also provides a significant positive psychological effect to the wearer because it adds greatly to his/her perception that his/her body is cooled.
The compartment in the cooling section is thus completely enclosed by a material that is impermeable to liquid water. This prevents the cooling section from "sweating", i.e. it does not expel liquid water so that the surface of the cooling section in the air does not feel humid. Instead, when water evaporates in the compartment, it may escape from the cooling section as water vapor because at least one of the outer layers of the cooling section is permeable to water vapor. It is also possible that both outer layers are permeable to water vapor.
The water-impermeability of the outer layers not only prevents the sweating, but also the inlet of water that is required for activation of the cooling garment. Thus, the garment cannot be activated by simply immersing it in water. Therefore, an inlet for water is present in one of the outer layers of the cooling section. This is usually an opening in one of the outer layers, preferably the layer that is not facing the body of a wearer of the garment. The water inlet may in principle be positioned anywhere on the surface of the cooling element. Preferably, however, it is present at the rear panel of the garment, since this is likely most comfortable to the wearer of the garment. The inlet is preferably provided with a closing element that prevents water from exiting the compartment via the water inlet. For example, the inlet can be closed with a zipper.
The presence of one compartment extending over the front and the rear panel has the advantage that only one water inlet is required to fill such compartment. The process of activating the garment is simple. After having added the appropriate amount of water through the water inlet, the garment is in principle ready for use. An equal spreading of the water in the compartment may be aided be shaking, swinging and/or flipping the garment prior to wearing the garment.
Even when a person wears an activated cooling garment, his/her body may well perspire. Since the cooling section in a garment of the invention is impermeable to water vapor, the sweat cannot be absorbed by the cooling section of the garment. Therefore, it is preferred that a cooling garment of the invention comprises vent holes through which evaporated sweat may escape. Preferably, the vent holes are present at those locations of the cooling garment where the torso underneath the garment has the highest density of sweat glands. Since the holes are completely open, also radiation (in particular infrared radiation) generated by the person wearing the cooling garment may be emitted through the holes.
The vent holes may in principle be of any shape. They may be of an elongated shape, such as a chink. They may also have a shape selected from the group of circular shape, elliptical shape, triangular shape, square shape and other polygonal shapes. Preferably, the vent holes are of a convex shape, in particular of a convex polygonal shape or a convex shape comprising a circular or non-circular arc. By a convex shape is meant a shape wherein the line segment joining any two points of the shape is contained in the shape or in the edge of the shape. Convex vent holes in a cooling garment of the invention in particular have their largest cross-section in the range of 1.0-10 cm, in particular in the range of 1.0-5.0 cm. It may also be in the range of 2.0-8.0 cm or in the range of 3.0-6.0 cm. Their aspect ratio is usually in the range of 1-5 or in the range of 2-4. It may also be in the range of 1.0-4.0 or in the range of 1.5-3.0. The total number of vent holes in the cooling section of a garment of the invention is usually in the range of 8-100. Preferably it is in the range of 10-50, more preferably it is in the range of 10-40.
Although the presence of the vent holes is at the expense of the cooling surface area (SA_cooling), it was surprisingly found that a cooling garment of the invention with vent holes not only prevented accumulation of sweat between the garment and the torso of the wearer, but also gave an effective cooling effect to the wearer of the garment, as well as a pleasant experience for the wearer. This was especially the case when the ratio of cooling surface area (SA_cooling) to open surface area (SA_open) is in the range of 80:10 to 98:2.0, in particular when it is in the range of 90:10 to 95:5.0. The ratio may also be in the range of 84:16 to 97:3.0 or in the range of 88:12 to 96:4.0.
The seal surface area (SA_seals) is preferably as small as possible since it does neither contribute to the cooling capacity of the cooling section (because the area is not available for evaporation of water), nor to the ventilation capacity of the cooling section (because the area is not open as in a vent hole). In alternative words, the ratio of open surface area (SA_open) to seal surface area (SA_seals) is preferably as high as possible, for example at least 60:40, at least 70:30, at least 80:20, at least 85:15, at least 90:10, at least 95:5 or at least 98:2.
However, a simple mathematical relationship prescribes that the ratio of open surface area to seal surface area of a vent hole decreases when the open surface area of the vent hole decreases. So, the presence of many small vent holes results in a too large seal surface area (SA_seals) and in a too low cooling capacity of the entire cooling section. On the other hand, the cooling garment is also functioning poorly when the number of vent holes is severely limited while their size is much larger. For example, the garment loses its structural integrity and it is difficult to reach a proper placement of the vent holes on those locations where the wearer's torso has the highest density of sweat glands. It was found that enough medium-sized vent holes can be realized together with sufficient cooling capacity, when the ratio of open surface area to seal surface area of a vent hole is at least 60:40, in particular at least 70:30, more in particular at least 80:20 and even more in particular at least 90:10.
For example, a cooling section has vent holes 1) with a seal width in the range of 0.1-0.5 cm; 2) with an open surface area in the range of 8-16 cm²; 3) with an aspect ratio in the range of 1.0-5.0; and 4) at a number in the range of 10-30. Such cooling section has 1) a sufficiently high ratio of open surface area (SA_open) to seal surface area (SA_seals); 2) a sufficiently high ratio of cooling surface area (SA_cooling) to open surface area (SA_open); and 3) vent holes that have advantageous dimensions (no too large, not too small) that allow concentrating the vent holes at desired positions.
Usually, a cooling garment of the invention comprises a non-cooling fabric that is attached to the cooling section, in particular to the circumferential edge of the cooling section. Such (conventional) fabric is in particular an elastic fabric, typically a knitted fabric. The function of such fabric is often to reach a more appealing look of the garment and/or to obtain a tight fit of the cooling section around the torso of the wearer. A tight fit results in a better heat transfer from the torso to the garment and thus to a more effective cooling garment.
As explained above, a cooling garment of the invention comprises a cooling section that does not extend under the arm pits of a wearer. If a connection between the front panel and the rear panel is desired under the arm pits, then this has to be realized with a different material, often a (conventional) fabric, that is connected to the cooling section.
Accordingly, a cooling garment of the invention may comprise

a first connection wherein a first section of the circumferential edge of the front panel is connected with a first section of the circumferential edge of the rear panel; and
a second connection wherein a second section of the circumferential edge of the front panel is connected with a second section of the circumferential edge of the rear panel;

The connection between the front panel and the rear panel may be permanent or releasable. For example, the first and/or the second connection may involve a releasable fastening means such as a zipper, velcro or buttons.
In case of a releasable connection, it is possible to adjust the size of the cooling garment to the wearer's torso by providing the front panel and the rear panel with releasable fastening means, such as velcro. It is an advantage of a garment of the invention that only a few sizes have to be available to serve a large range of torso dimensions. This would not be possible with garments that have the cooling section around the entire torso.
Another advantage of a cooling garment of the invention is that the outer layers can efficiently be cut out of a roll of fabric to thereby generate only few scrap cuttings. This contrasts with the situation wherein the shaping of the outer layers would include the parts that reach beneath the arm pits, which parts are extremities that are more or less perpendicular to the front panel and the rear panel. In addition, since the front panel and the rear panel are made out of one piece of material (each outer layer is made in one piece), there is no need to connect different panels of the garment. This would severely complicate the manufacture of the garment, since the connection of the panels would also require that a fluid communication between the panels is realized.
The materials of the outer layers are preferably thermoplastic materials. By thermoplastic is meant the property of a material, usually a polymer, that it becomes soft when heated and hard when cooled. When both layers comprise a thermoplastic material, then this is advantageous when the sealing between bot layers is obtained by heat fusion.
The two outer layers may, independently of each other, comprise a thermoplastic material selected from the group of acrylate polymers, acrylate copolymers, methacrylate polymers (such as poly(methylmethacrylate)), methacrylate copolymers, polyesters (such as polyethylene terephthalate), polyolefins (such as polypropylenes, polyethylenes, polymethylpentenes, polystyrenes and polybutylenes), polyurethanes, poly(ether-ester) elastomers, poly(vinylacetate), ethylene-vinyl acetate co-polymers, vinyl ester polymers, and mixtures thereof.
The materials of the two outer layers are often the same. This usually provides the best, and in particular the strongest, seal between both layers. In order to be fusible, however, the materials of both outer layers do not necessarily have to be the same. For example, two materials with comparable molecular structure and similar glass transition temperatures may also be fusible with each other. The person skilled in the art knows which different materials are fusible, or at least will be able to provide such materials by routine experimentation and without exerting inventive effort. When both outer layers are of different materials, then this is often for reasons of wearing comfort and/or visual appearance of the multi-layered fabric of the invention.
In a preferred embodiment, the front panel is divided into a first part and a second part along a line that runs from the neck opening to the circumferential edge. With such configuration, the cooling garment may be opened on the front panel as a normal jacket with a left flap and a right flap, without splitting the compartment into two compartments. This is because each flap stays in fluid communication with the second portion of the compartment (i.e. the portion on the other side of the neck opening). This fluid communication occurs along one side of the neck opening, i.e. for each flap over one shoulder when the garment is worn). Thus, in a cooling garment of the invention, the front panel may be divided into a first part and a second part along a line that runs from the neck opening to the circumferential edge, wherein the first portion of the compartment of the cooling section is also divided into two parts, each part being in fluid communication with the second portion of the compartment of the cooling section. Thus, the first part of the front panel comprises one part of the first portion of the compartment, and the second part of the front panel comprises another part of the first portion of the compartment.
Usually, the line that defines the division of the front panel into the first part and the second part of the front panel runs from the neck opening over the belly to the waist, when the garment is worn by a person. Thus, such line is perpendicular to the (imaginary) line that connects both shoulders of a person wearing the garment.
The first part and the second part of the front panel can be attached to one another along the line that runs from the neck opening to the circumferential edge. The attachment may be performed by means of a zipper, velcro or buttons.
Thus, a cooling garment of the invention has the advantage that it can be equipped with a zipper all the way from the neck opening to the waist as if it were a conventional vest not having a compartment for water that extends over the front panel. The zipper can be introduced without making sacrifices to the cooling properties and the comfort of the cooling garment; neither are changes required to the lay-out of the cooling section, other than introducing a seal that extends parallel to the zipper (after all, the cooling garment with zipper still comprises one single compartment for water, all portions of which are in fluid communication with one another).
It is also possible that the division is in the rear panel instead of the front panel, and that the rear panel comprises a first part and a second part, wherein both parts can be attached by means of a zipper, velcro or buttons that is present at the back of the person wearing the cooling garment.
The water absorbent layer is capable of absorbing water by the presence of a water-absorbing polymer in the layer. Such polymers may be natural polymers such as cellulose, or non-natural polymers such as so-called superabsorbent polymers (SAP). In a cooling garment of the invention, the water-absorbing polymer is preferably a SAP. The water absorbent layer may essentially consist of the SAP, but it may also comprise an additional material that serves as a support for the SAP. Thus, the water absorbent layer may comprise a support material and a superabsorbent polymer.
By a superabsorbent polymer is meant a water-swellable polymer that is capable of absorbing at least 20 times its weight in water. A polymer that is suitable for use as a superabsorbent polymer in a multi-layered fabric of the present invention may be a synthetic superabsorbent polymer selected from the group of polyacrylates, polyacrylamides, polyvinyl alcohols, ethylenemaleic anhydride copolymers, polyvinylethers, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, polyvinylmorpholinones, polyacrylamides, polyvinylpyridines, and polyvinylpyrrolidones.
The support material may in principle be the same material as the material of the outer layers, i.e. it may in principle be chosen from the list given above for the possible materials of the outer layers. The support material is for example a polyester or a polyolefin selected from the group of polyethylene, polypropylene, poly(ethyleneterephthalate) and (random) copolymers of polypropylene and polyethylene. Suitable polyethylenes include linear low density polyethylene and high density polyethylene. Preferably, the support material comprises a (shredded) polyester or substantially consists of a (shredded) polyester.
The support material and the SAP may in principle be present in any weight ratio. The support material usually constitutes up to 95 wt.% of the water absorbent layer. It may also constitute 10-95 wt.% or 25-90 wt.% of the water absorbent layer. Preferably, it constitutes 30-85 wt.% of the water absorbent layer, more preferably 40-80 wt.%. The SAP is usually present in such amount that it constitutes at least 2 wt.% of the water absorbent layer. It may also constitute at least 5 wt.%, at least 10 wt.% or at least 15 wt.% of the water absorbent layer. When the water absorbent layer is included in the fusion, then the SAP is preferably present in moderate amounts, for example up to 40 wt.%, up to 35 wt.%, up to 30 wt.%, up to 25 wt.%, up to 20 wt.%, up to 15 wt. % or up to 10 wt.%. All contents mentioned are based on absorbent material in the absence of absorbed water.
The support material in the water absorbent layer may be present as fibers, e.g. particles with an aspect ratio of at least 10, more preferably at least 25. The aspect ratio may also be at least 50 or at least 100. By the aspect ratio of a fiber is meant the ratio between the length of the fiber and the width of the fiber (wherein the width is the largest cross-section of the fiber perpendicular to its length). The width of the fibers is usually in the range of 1.0-500 µm. In particular, it is in the range of 5.0-200 µm, more in particular in the range of 10-100 µm.
When the support material is present as fibers, the absorbent layer that results from mixing the fibers with the SAP is stronger and is better manageable during the manufacturing of the cooling device (e.g. is not easily disrupted or deformed).
The SAP may be present as beads but also as fibers. The advantage of fibrous SAP is that it is easier to reach a uniform distribution of the SAP in the support material, especially it easily mixes with the support material when the support material is also present as fibers. When the SAP is present as beads (e.g. particles wherein the largest dimension is not more than 5 times, not more than 3 times or not more than 2 times larger than the smallest dimension), demixing of the SAP from the support material easily occurs, which leads to a non-uniform distribution of SAP in the support material.
The aspect ratio of fibers of SAP, if present, is preferably at least 10, more preferably at least 25. The aspect ratio may also be at least 50 or at least 100. By the aspect ratio of a fiber is meant the ratio between the length of the fiber and the width of the fiber (wherein the width is the largest cross-section of the fiber perpendicular to its length). The width of the fibers is usually in the range of 1.0-500 µm. In particular, it is in the range of 4.0-250 µm, more in particular in the range of 6.0-100 µm and even more in particular in the range of 10-50 µm.
The invention further relates to an activated cooling garment, wherein water is contained in the compartment of a cooling garment as described hereinabove, so that the water is absorbed by the absorbent layer and capable of permeating as a vapor through one or both outer layers after it has been evaporated in the compartment.

Claims

A cooling garment (1) for cooling a torso of a wearer, comprising a front and a rear panel (3, 4) with a neck opening (5) therebetween, wherein
- the front panel and the rear panel (3, 4) comprise one single cooling section (2) that forms at least a portion of the front panel (3) and at least a portion of the rear panel (4), the cooling section (2) comprising
∘ a neck opening (5) that coincides with the neck opening (5) of the cooling garment, the neck opening (5) defining a neck opening surface area (SA_{neck opening});

∘ a cooling surface area (SA_cooling);

∘ a circumferential edge (6a) and a neck edge (6b);

- the cooling section (2) is made of a cooling material comprising
o two outer layers that are impermeable to liquid water, at least one of the outer layers being permeable to water vapor;

∘ a water absorbent layer that is enclosed between both outer layers;

- the two outer layers are sealed together along the circumferential edge (6a) and the neck edge (6b) to form a single compartment (7) for the storage of water, the compartment (7) having a first portion (7a) at the front panel (3) and a second portion (7b) at the rear panel (4), both portions being in fluid communication with one another;

- the compartment (7) comprises an inlet (8) for water.
A cooling garment (1) according to claim 1, wherein the cooling section (2) comprises vent holes (9) through which a fluid may pass, wherein
- the vent holes (9) are defined by coinciding vent hole edges (6c) of the two layers;

- the outer layers are sealed together along the vent hole edges (6c) to form a seal around each vent hole (9) having a seal surface area (SA_{vent hole seal});

- the vent holes (9) define an open surface area (SA_{vent holes}).
A cooling garment (1) according to claim 2, wherein the vent holes (9) have a shape selected from the group of circular shape, elliptical shape, triangular shape, square shape and other polygonal shapes.
A cooling garment (1) according to claim 2 or 3, wherein the ratio of cooling surface area (SA_cooling) to open surface area (SA_open) is in the range of 80:20 to 98:2.0, in particular it is in the range of 90:10 to 95:5.0, wherein the open surface area (SA_open) is the sum of the neck opening surface area (SA_{neck opening}) and the vent holes surface area (SA_{vent holes}).
A cooling garment (1) according to any one of claims 2-4, wherein the seal around each vent hole (9) has a width in the range of 1-10 mm, in particular in the range of 2-5 mm.
A cooling garment (1) according to any one of claims 2-5, wherein the vent holes (9) have their largest cross-sectional dimension in the range of 1-10 cm, in particular in the range of 1-5 cm.
A cooling garment (1) according to any one of claims 2-6, wherein the number of vent holes (9) is in the range of 10-100, preferably in the range of 20-50.
A cooling garment (1) according to any one of claims 1-7, comprising a
- a first connection means (12a) capable of connecting a first section of the circumferential edge of the front panel with a first section of the circumferential edge of the rear panel; and

- a second connection means (12b) capable of connecting a second section of the circumferential edge of the front panel with a second section of the circumferential edge of the rear panel;
wherein the connection realized with the first connection means (12a) defines a first arm hole of the garment and the connection realized with the second connection means (12b) defines a second arm hole of the garment.
A cooling garment (1) according to claim 8, wherein one or both realized connections are made by releasable connection means such as a zipper, velcro or buttons.
A cooling garment (1) according to any one of claims 1-9, wherein the front panel (3) is divided into a first part (3a) and a second part (3b) along a line (11) that runs from the neck opening (5) to the circumferential edge (6a), wherein the first portion (7a) of the compartment (7) is also divided into two parts (7a1, 7a2), each part (7a1, 7a2) being in fluid communication with the second portion (7b) of the compartment (7) of the cooling section (2).
A cooling garment (1) according to claim 10, wherein the first part and the second part of the front panel can be attached to one another along the line that runs from the neck opening to the circumferential edge, for example by means of a zipper, velcro or buttons.
A cooling garment (1) according to any one of claims 1-11, wherein the outer layers comprise a thermoplastic material selected from the group of acrylate polymers, acrylate copolymers, methacrylate polymers, methacrylate copolymers, polyesters, polyolefins, polyurethanes, poly(ether-ester) elastomers, poly(vinylacetate), ethylene-vinyl acetate co-polymers, vinyl ester polymers, and mixtures thereof.
A cooling garment (1) according to any one of claims 1-12, wherein the water absorbent layer comprises a support material and a superabsorbent polymer, preferably wherein the support material constitutes 25-95 wt.% of the water absorbent layer.
A cooling garment (1) according to claim 13, wherein the support material is a thermoplastic material selected from the group of polyethylene, polypropylene, (random) copolymers of polypropylene and polyethylene, poly(ethyleneterephthalate), and mixtures thereof.
A cooling garment (1) according to any one of claims 1-14, wherein both outer layers are permeable to water vapor.