Cooling cap for the scalp

Abstract

A heat exchange cap and method of making the same, the heat exchange cap configured to be worn on a person's head to regulate head temperature. The cap includes a layer of material defining a single passageway through which a heat transfer fluid can flow, and the single passageway extends from a single inlet to a single outlet, the layer of material having a first side for contact with the head and a second side that will face away from the head when in use.

Description

Technical Field

[0001] This invention relates to a scalp cooling cap for use on the head of a patient receiving chemotherapy or similar treatments that may cause hair loss. Background Technology

[0002] Chemotherapy-induced alopecia (CIA) is widely recognized as one of the most distressing side effects of chemotherapy. Without treatment, CIA affects 3.5 million patients worldwide each year, including over 67,000 in the UK.

[0003] It is known that cooling the patient's head during chemotherapy can reduce the degree and / or likelihood of hair loss through vasoconstriction.

[0004] EP3197407B discloses a heat exchange cap configured to be worn on a person's head to regulate head temperature. The cap includes a material layer defining a single channel through which a heat transfer fluid can flow, and the channel extends from a single inlet to a single outlet. The material layer defines a first element for covering one side of the head, a second element for covering the opposite side of the head, and an intermediate connecting element configured to cover the top of the head. Each of these elements defines a portion of the single channel passing through the cap. The material layer has a first side for contact with the head and a second side that will be away from the head during use. At least in the first and second elements, the single channel defines a first flow region located on the side opposite to a second flow region at a junction line, each flow region extending only a portion of the distance from the front to the rear of the cap. The channel has a serpentine path in each element, and the serpentine path extends back and forth in a direction from the nominal front to the nominal rear of the cap. The channel in the first flow region has a serpentine path extending back and forth on the front half of the side of the cap, which corresponds to the front half of the side of the head to be worn. The channel in the second flow area has a serpentine route that extends back and forth on the rear half of the side of the cap, which corresponds to the rear half of the head to be worn.

[0005] This known heat exchange cap is made of silicone material through thermoforming of silicone sheets.

[0006] There is a need for a recyclable individual patient scalp cooling cap and a method for manufacturing it. Summary of the Invention

[0007] According to a first aspect of the invention, a heat exchange cap is provided, configured to be worn on a human head to regulate the temperature of the human head, the cap comprising a material layer defining a single channel through which a heat transfer fluid may flow, and the single channel extending from a single inlet to a single outlet, the material layer having a first side for contact with the head and a second side that will be away from the head in use, one of the first side and the second side being shaped to partially define the single channel, while the other of the first side and the second side is unshaped.

[0008] According to a second aspect of the invention, a heat exchange cap is provided, configured to be worn on a human head to regulate the temperature of the human head, the cap comprising a material layer defining a single channel through which a heat transfer fluid may flow, the single channel extending from a single inlet to a single outlet, the material layer having a first side for contact with the head and a second side that will be away from the head during use, the material being thermoplastic polyurethane.

[0009] Preferably, the material has a Shore hardness of 60A to 95A, more preferably about 70A.

[0010] The cap preferably has the material layer defining a first element for covering one side of the head, a second element for covering the opposite side of the head, and an intermediate connecting element configured to cover the top of the head, each of the elements defining a portion of the single channel through the cap.

[0011] A third aspect of the invention provides a method for manufacturing a heat exchange cap, the method comprising vacuum forming a first molded part and a second molded part, the first molded part having a surface pattern defining one side of a material layer and the first molded part defining the other side of the material layer; welding the first molded part to an unformed second molded part to form a two-dimensional heat exchange cap precursor having partially separated portions; and welding adjacent pairs of said portions together to form a three-dimensional cap.

[0012] Preferably, the first molded part is welded to the second molded part by radio frequency welding.

[0013] Preferably, the welding to form the three-dimensional cap includes spot welding.

[0014] Preferably, the welding forming the three-dimensional cap also includes bar welding between spot welds.

[0015] Preferably, the three-dimensional cap is formed without the use of glue, thereby maintaining the sustainability and repeatability of the product.

[0016] In a fourth aspect, the present invention provides a two-dimensional precursor for a heat exchange cap, the precursor comprising a material layer defining a single channel through which a heat transfer fluid may flow, and the material layer extending from a single inlet to a single outlet, the material layer having a first side for contact with a head and a second side that will be away from the head during use, one of the first side and the second side being shaped to partially define the single channel, while the other of the first side and the second side is unshaped.

[0017] In a fifth aspect, the present invention provides a cap cover for a heat exchange cap, the cap cover comprising a three-layer laminate of polyurethane, thermoplastic polyurethane and nylon.

[0018] Both the cap and the cap cover are made of thermoplastic, which can be remolded by heating, in contrast to the use of thermosetting plastics such as silicone currently in use. The materials used in this invention not only promote recyclability and sustainability but also enable performance improvements.

[0019] Preferably, the welding is radio frequency (RF) welding, in which heat is generated by passing radio frequency radiation through the plastic material, causing it to melt and bond together. The sheet thickness is typically from 150 micrometers to 1400 micrometers.

[0020] The heat exchange cap according to the invention helps cool the scalp. Scalp cooling helps protect hair follicles, which are rapidly dividing cells targeted by chemotherapy drugs. Scalp cooling promotes vasoconstriction, reduces drug uptake by cells, reduces hair follicle cell division, and lowers metabolic activity, thereby reducing / preventing hair loss. Attached Figure Description

[0021] The attached image is as follows: Figure 1 This shows a vacuum-formed TPU sheet; Figure 2 The vacuum forming process is shown; Figure 3 This shows the positioning of the molded TPU in the RF tooling; Figure 4 This shows a molded TPU sheet; Figure 5 Showing details of the molded TPU sheet; Figure 6 and Figure 7 Demonstrates the operation of spot welding tools; Figure 8 The spot weld points on the front of the two-dimensional cap are shown; Figure 9 This illustrates the process of spot welding together; Figure 10 Show the three-dimensional hat; Figure 11Showing the rear quarter of the spot weld on the cap; and Figure 12 The front part of the spot weld on the cap is shown. Detailed Implementation

[0022] The present invention will now be described by way of example only with reference to the accompanying drawings.

[0023] The cap's function is to make good contact with the head and remove heat from the scalp. Heat from the scalp is transferred through the inner layer of the cap to the cooling liquid that carries away the heat. Importantly, the inner layer has a sufficient heat transfer coefficient determined by a combination of thermal conductivity and thickness. These two properties determine the U-value of the inner layer, i.e., the heat transfer coefficient, which is the specific heat capacity (thermal conductivity value) of the material divided by the thickness of the material.

[0024] In Fourier's law, Q = (k / s) x A x dT, where (k / s) is U.

[0025] The coolant must have a good flow rate to quickly remove heat from the scalp, thus overcoming the scalp's natural thermoregulation. This requires the coolant channels to have a sufficient cross-sectional area to allow for good flow while maintaining the lowest possible pressure to prevent bursting. Lower pressure also allows for the use of thinner layers, thus providing an improved U-value.

[0026] This invention relates to a heat exchange cap comprising a material layer defining a channel through which a heat transfer fluid flows. The material layer has a first side for contact with an object and a second side that will be away from the object during use.

[0027] The first inner side 2 has a layer formed by vacuum forming to improve flow by increasing the cross-sectional surface area.

[0028] The vacuum-formed inner side 2 has a relatively high thermal conductivity to facilitate heat extraction from the patient's hair / head, thereby retaining more hair.

[0029] This material has a high thermal transfer coefficient and specific heat capacity, thus enabling better heat extraction than existing products.

[0030] Each side is made of thermoplastic polyurethane (TPU), preferably bonded without the use of glue. The material preferably has a Shore hardness of 70A and is durable, resistant to bursting and pinhole leakage. The use of spot-and-strip welding in the manufacture of the cap makes it tear-resistant and resistant to tail splitting.

[0031] Due to the flexibility of the TPU material, this heat exchange cap fits comfortably to various anthropomorphic head shapes. In practice, different shapes and sizes are available; for example, two shape categories with three sizes for each shape category, totaling six caps. However, the flexible properties of the material used to manufacture the cap allow for a degree of flexibility to suit different users.

[0032] The main body of the cap is a well-designed heat exchanger with a flow pattern.

[0033] Layout: It is designed to provide a single flow channel arrangement with optimal flow and surface contact, and to provide heat exchange that fits closely to the user's scalp to draw heat from the patient's head.

[0034] The materials used to manufacture this cap are biocompatible, soft, flexible, and highly chemically resistant. They are aesthetically pleasing, comfortable, and malleable medical-grade materials.

[0035] The coolant tubing / tail section connecting the cap to the system is made of silicone / TPU or similar tubing, insulated with neoprene and covered with a fabric sheath, typically about 2 meters long. This allows for sufficient distance between the machine and the patient, and enables the head / person / device to move around the patient's seat.

[0036] The cap features a fabric cover that acts as an outer cap, encasing the heat exchange cap to insulate it from heat loss into the surrounding atmosphere and to further compress the heat exchange cap onto the head. The cover also serves an aesthetic purpose.

[0037] The cap features a biocompatible chin strap and is designed to be pulled down onto the scalp via an adjustable strap to press the cap against the head for optimal scalp contact and to enhance therapeutic efficacy.

[0038] Molding of two-dimensional cap precursor The current silicone cap is formed using a process called sheet silicone thermoforming, in which raw sheet silicone is molded and shaped using a 3D-printed SLS (Selective Laser Sintering) tool. The cap has a shape on both sides of the tool (male and female mold halves). One side is semi-circular, and the other side has a "w" shaped profile as described in WO / 2016 / 046534.

[0039] The heat exchange cap made of TPU material of the present invention is manufactured using an RF soldering process with metal tools that do not mold the TPU in the same way. The method of the present invention involves adding a step (vacuum forming) before the soldering process and before the 3D molding process. The cap is produced using the following main steps: 1. Vacuum forming of TPU sheets; 2. Position the single-sided shaped sheet into the RF welding tool; 3. Place the individual unformed sheets onto the formed sheets in the tool room; 4. Then weld the cap (to weld the flat sheet half and the shaped sheet half together).

[0040] RF welding after TPU vacuum forming has never been used before, especially with this level of complexity and intricate geometry. It has also never been used in conjunction with processes that transform caps from two-dimensional to three-dimensional. A "W"-shaped profile can be used; its specific deformation properties allow the "W" to expand when pressure is applied to close any gaps created by the welded walls between the channels. By using the "W"-shaped profile to close these gaps, the surface area used is maximized, making it a highly efficient heat exchanger for the purpose of preventing hair loss during chemotherapy-induced alopecia.

[0041] The vacuum forming tooling design used in this process differs from that used in conventional vacuum forming. The material used (TPU) has a much lower glass transition temperature. This results in significant bending of the sheet material, potentially causing positioning and welding problems in subsequent manufacturing steps. The cap tool utilizes a flat upper surface surrounding the molding area to provide a larger surface area for welding and cutting processes, and to increase the surface area for dissipating heat during the manufacturing process. Furthermore, around the outer perimeter of the tool, the flat area is pulled taut and downwards around the tool sides using a 15-degree or similar draft angle. Additionally, as shown in the attached figures… Figure 1 As shown, positioning points were added in the welding tool, and supports were added to increase tension and reduce warping.

[0042] Variables in the vacuum forming process include the specific TPU material, duration, vacuum pressure used, exposure time to heat, and temperature of the heat. Similar to conventional vacuum forming, the plastic is heated to soften / sag, and then a mold is pressed into the softened plastic. Here, the vacuum pulls the material into the mold and removes heat to cool the plastic within the mold.

[0043] The attached image Figure 2 The upper section shows the clamped TPU sheet and the application of specific heat above the sheet to soften the plastic. The lower section illustrates how specific pressure is applied when the mold is pushed into the softened TPU. This specific pressure is the air pressure that pulls the material down into the mold. This involves the magnitude of the pressure used to draw the softened plastic into the mold to form it as the material "sets" / cools and to maintain a vacuum around the material. If it's too low, the molding will be poor; if it's too high, the plastic will crack.

[0044] The attached image Figure 3This demonstrates how molded TPU from a vacuum forming tool is positioned into an RF tool prior to the soldering process.

[0045] The attached image Figure 4 This shows a molded TPU sheet. Figure 5 Details of the molded TPU sheet are shown, where the "w" shaped outline is represented by the wavy grooves at the bottom of the groove.

[0046] Forming a three-dimensional cap from a two-dimensional precursor Typically, RF welding is a flat, two-dimensional manufacturing process only for sheet plastic materials. Due to the nature of the manufacturing process, three-dimensional molds and three-dimensional molding are not used. The method of this invention enables manufacturers to produce flat parts that are subsequently transformed into three-dimensional shapes. For specific applications where such flat shapes need to be molded around the human head, which is arguably one of the most complex shapes in the external anatomy of the human body, this is a considerable engineering feat.

[0047] In fact, current silicone caps have been reverse engineered by taking a complete thermoformed TPU sheet and cutting between welded walls between heat exchanger channels to flatten the pattern. This allows existing caps to retain their current shape, but allows the exact same pattern currently molded in a three-dimensional shape to be manufactured using a two-dimensional pattern and a two-dimensional process. Subsequently, additional features are added that allow the two-dimensional pattern to be formed into a three-dimensional shape using additional welding processes at the seams.

[0048] After the TPU sheet is vacuum-formed, a metal stamping and cutting tool cuts around the perimeter of the cap. Within this perimeter, cutting and welding allowances are added for subsequent steps. Incremental patterned spot weld anchor points are added. The spot weld points have the following characteristics: • The diameter of the positioning point at the center of the weld is 5mm.

[0049] • It is circular to prevent operators from mispositioning and misusing it.

[0050] • It has specific spacing between the gaps to allow for further welding processes between the gaps, thereby ensuring that the joints can be completely welded without the use of glue, in order to maintain sustainability and repeatability.

[0051] • It has a minimum offset weld wall thickness (1-3mm) to ensure proper welding and gripping force between tool materials, thereby preventing breakage, melting, collision and impact during this tack welding process.

[0052] • When welding the walls later, the positioning point is offset far enough from the outer bend of the heat exchanger wall to prevent the channels from thinning and closing (to maintain equal channel diameters for flow and performance). This also prevents the formed channels from cracking due to heat from spot welding.

[0053] • The spot welding positioning points are matched with the corresponding spot welding positioning points, i.e., AA, BB, etc.

[0054] • The outer edge of the spot weld must not encroach on the available material of the adjacent spot weld to which it will be matched, so as not to reduce the minimum perimeter welding allowance of the positioning hole.

[0055] • Spot welding positioning points can be welded from the outside by the operator.

[0056] • Spot weld upwards and join on the outside of the cap to avoid affecting the fit, comfort, or performance of the cooling cap in the area where it interacts with the user's head.

[0057] • Spot welding anchors are used to pull the seams of the two-dimensional cap pattern inward so as to transform the shape of the cap in a way that does not cause wrinkles, folds or other defects that may be expected when a two-dimensional shape is transformed into a three-dimensional shape in a flat sheet.

[0058] • The cap forming process prevents coolant channels from becoming blocked.

[0059] • The cap's formation provides a close fit to the head, typically managed through strategic positioning of the locating spot welds, whereby the equidistant spacing from the innermost point of the cut TPU between the two seams is equal to prevent material buildup at the joint.

[0060] • The formation of the cap seam from two-dimensional to three-dimensional minimizes the gaps between channels. Large gaps between cooling channels can inhibit, for example, the maximum surface contact provided by the "w" shaped channel profile.

[0061] In the attached diagram Figure 6 and Figure 7 The spot welding tool 6 shown has a plastic male locating point that enters a hole on each side of the joint when the seams are pulled together. For the joint to be welded, each side of the gap wall (weld wall) has a circular locating point profile within it. Each hole (two in total) is oriented upwards and outwards toward the cap, providing an "L"-shaped profile perpendicular to the cap surface (or tangentially). The locating point welding tool consists of two halves. On one side, a plastic male locating post is located inside the circular welding tool profile. On the opposite tool, the circular welding tool has a recess to allow the male locating post to be accurately positioned at a set distance from the cap, preventing mispositioning and potential damage to the cap channel wall.

[0062] The cap has a set number of spot welds that transform the cap from two-dimensional to three-dimensional. (See attached diagram.) Figure 8 As shown, the flat cap pattern has an optimized number of "finger-like parts" 8, for example, 6 to 10. The figure below shows the "finger-like parts" of the cap, with the spot welds indicated by black lines, representing the connection positioning points that are welded together to form a three-dimensional shape.

[0063] As shown in the attached figure Figure 8 As shown, it has: • 44 spot welding positioning points These positioning points form 22 spot welding points. • That is, there are 7 spot welds in the rear quarter quadrant of the cap and 4 spot welds in the front quarter quadrant of the cap (or there are 14 spot welds in the rear part of the cap and 8 spot welds in the front part).

[0064] • There are 8 gaps between the "finger-like parts" of the cap that need to be closed to form the cap.

[0065] The attached image Figure 9 This demonstrates the process of welding spot welds together. Figure 10 The appearance of the cap after spot welding is shown.

[0066] The method for welding the cap from two dimensions to three dimensions to maximize repeatability and reduce complexity is as follows. The principle is the same as above, but instead of welding 22 spot welds individually, these spot welds are paired together with equal spacing, as mentioned in the text above. Bar welding is used to join the paired spot welds to reduce the processes / operations required to form the cap.

[0067] For the rear half of the cap, the seven spot welds are spaced 40mm apart along the entire seam. The distance from the seam start point is directly related to the entire length of the seam curve, the equidistant spacing of the number of spot welds, and the equal gaps between the seam start point and the first spot weld, as well as between the curve end point and the last spot weld. (See attached diagram.) Figure 11 The rear quarter of the spot weld points on the cap is shown. These are mirror images on opposite sides.

[0068] For the front half of the cap, the spacing between the spot welds varies. The four spot welds on the front are spaced 30mm apart along the entire seam. (See attached diagram.) Figure 12 The spacing between the spot welds in the front quarter of the cap is shown—these are mirrored on opposite sides.

[0069] Essentially, the above process combines two welding methods—spot welding and bar welding—into a novel hybrid process for 3D applications. This optimizes the process and improves its repeatability.

[0070] This process ensures equidistant and controlled welding of seams to achieve manufacturing accuracy and repeatability, while also minimizing the number of steps, reducing manufacturing costs and time.

Claims

1. A heat exchange cap configured to be worn on a person's head to regulate head temperature, the cap comprising a material layer defining a single channel through which a heat transfer fluid may flow, and the single channel extending from a single inlet to a single outlet, the material layer having a first side for contact with the head and a second side that will be away from the head during use, one of the first side and the second side being shaped to partially define the single channel, while the other of the first side and the second side being unshaped.

2. A heat exchange cap configured to be worn on a person's head to regulate head temperature, the cap comprising a material layer defining a single channel through which a heat transfer fluid may flow, and the single channel extending from a single inlet to a single outlet, the material layer having a first side for contact with the head and a second side that will be away from the head during use, the material being thermoplastic polyurethane.

3. The cap according to claim 2, wherein the material has a Shore hardness of 60A to 95A.

4. The cap according to any one of the preceding claims, wherein the material layer defines a first element for covering one side of the head, a second element for covering the opposite side of the head, and an intermediate connecting element configured to cover the top of the head, each of the elements defining a portion of the single channel passing through the cap.

5. A method of manufacturing a heat exchange cap, the method comprising vacuum forming a first molded part having a surface pattern defining one side of the material layer and a second molded part defining the other side of the material layer, welding the first molded part to the unformed second molded part to form a two-dimensional heat exchange cap precursor having partially separated portions, and welding adjacent pairs of the portions together to form a three-dimensional cap.

6. The method according to claim 5, wherein, The first molded part is welded to the second molded part by radio frequency welding.

7. The method according to claim 5 or 6, wherein, The welding that forms the three-dimensional cap includes spot welding.

8. The method according to claim 7, wherein, The welding that forms the three-dimensional cap also includes bar welding between spot welds.

9. The method according to any one of claims 5 to 8, wherein, The three-dimensional cap is formed without the use of glue.

10. A two-dimensional precursor for a heat exchange cap, the precursor comprising a material layer defining a single channel through which a heat transfer fluid can flow, and the single channel extending from a single inlet to a single outlet, the material layer having a first side for contact with a head and a second side that will be away from the head during use, one of the first side and the second side being shaped to partially define the single channel, while the other of the first side and the second side being unshaped.

11. A cap cover for a heat exchange cap, the cap cover comprising a three-layer laminate of polyurethane, thermoplastic polyurethane and nylon.

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