Shipping package with inner envelope containing phase change material

Abstract

A temperature-controlled shipping package is disclosed. The package includes an outer envelope and an inner envelope, creating multiple thermal control spaces. An intermediate space between the envelopes contains a removable thermal unit, such as an ice pack, which can be frozen separately. The inner envelope is lined with phase-change material, and the outer envelope includes a thermally insulative sheet. This design prevents overcooling, reduces required freezer space, and maintains a stable temperature for the shipped product over extended periods. The solution offers cost-effective temperature control and simplifies the shipping process without the need for seasonal adjustments.

Description

SHIPPING PACKAGE WITH INNER ENVELOPE CONTAINING PHASE CHANGE MATERIALCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to US provisional application 63 / 668,900, filed July 9, 2024. The entire contents of the foregoing are incorporated herein by reference.FIELD

[0002] The present specification is directed to shipping packages, and particularly temperature-controlled shipping packages.BACKGROUND

[0003] Temperature control during shipping is critical for various products, particularly perishable goods, pharmaceuticals, and certain chemicals. Existing techniques for providing temperature control to shipped products suffer from a number of significant problems.

[0004] One common approach involves the use of shipping containers with Phase Change Materials (PCM). While PCMs are effective at maintaining a specific temperature range, they are prohibitively expensive for most packaging applications, making them less feasible for widespread use. For a PCM to be effective it must undergo a phase change during the shipment which needs to be done in a controlled, repeatable fashion. Freezing the complete package including a PCM is not a practical solution, since shipping packages are bulky, and a frozen PCM mat can overcool a temperature-sensitive payload. Although substantially more cost-effective, water or gel-based ice packs can similarly cause the product to become too cold, potentially damaging temperaturesensitive items.

[0005] Furthermore, both PCM and water-based methods generally require modification, such as of the components, assembly procedure or their pre-conditioning process, based on seasonal variations. For instance, different configurations or materials are needed to maintain the desired temperature in summer versus winter conditions. Thisseasonal adjustment adds complexity and cost to the shipping process.SUMMARY

[0006] An aspect of the specification provides a shipping package comprising an outer envelope having a closed end and a closeable end. The envelope defines a first thermal control space. A first insulative sheet is positioned within the first thermal control space. An inner envelope is disposed within the outer envelope. The inner envelope defines a second thermal control space and an interior space that is separate from the first and second thermal control spaces. The interior space is configured to contain a payload. An intermediate space is defined by the inner envelope and the outer envelope. The intermediate space is separate from the first and second thermal control spaces and is configured to receive a removable thermal unit therebetween. A phase-change material mat is positioned within the second thermal control space for moderating thermal effects of the removable thermal unit.

[0007] In one example, the phase-change material mat is permanently sealed within the second thermal control space, and the first insulative sheet is permanently sealed within the first thermal control space.

[0008] In one example, a second insulative sheet is permanently sealed within the second thermal control space and positioned to insulate the phase-change material mat from the removable thermal unit.

[0009] In one example, a third insulative sheet is permanently sealed within the second thermal control space and positioned to insulate the phase-change material mat from the payload.

[0010] In one example, the second insulative sheet is selected from foam, foil, bubble wrap, fiberglass, aerogel, and fibrous materials.

[0011] In one example, the second insulative sheet is selected from open-cell polyurethane foam, expanded polyethylene foam, ethylene-vinyl acetate foam, corn starch foam, and plant fiber-based foam.

[0012] In one example, the first insulative sheet is selected from cellulose, open-cellpolyurethane, natural rubber, synthetic rubber, foam, cotton, and hemp.

[0013] In one example, the first insulative sheet is selected from open-cell polyurethane foam, expanded polyethylene foam, ethylene-vinyl acetate foam, corn starch foam, and plant fiber-based foam.

[0014] In one example, the phase-change material has a phase-transition temperature selected to correspond to a target temperature for the payload.

[0015] In one example, a resealable closure is provided at the closeable end for closing the outer envelope.

[0016] In one example, the inner envelope is removably attached to the outer envelope.

[0017] In one example, the phase-change material mat includes a plurality of cells for containing phase-change material.

[0018] In one example, the plurality of cells includes a plurality of phase-change materials having different phase-transition temperatures.

[0019] In one example, a protective enclosure is included, selected from an envelope, box, sleeve, and wrap.

[0020] In one example, a fourth insulative sheet is positioned within the first thermal control space at the sides of the shipping package.

[0021] In one example, one or more non-flexible insulative sheets are included for providing structure to the shipping package.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a perspective view of an example shipping package according to the present disclosure.

[0023] Figure 2A is a side cross-sectional view of the example shipping package of Figure 1 along section line A-A.

[0024] Figure 2B is a front cross-sectional view of the example shipping package ofFigure 1 along section line B-B.

[0025] Figure 3 is a perspective view of the example shipping package of Figure 1 in an open configuration.

[0026] Figure 4 is a perspective view of another example shipping package according to the present disclosure.

[0027] Figure 5A is a plan view of an example phase-change material mat according to the present disclosure.

[0028] Figure 5B is a plan view of another example phase-change material mat according to the present disclosure.

[0029] Figure 6 is a plan view of another example phase-change material mat according to the present disclosure.

[0030] Figure 7 is a graph showing a temperature profile of the shipping package of Figure 1 according to Example 1 .

[0031] Figure 8 is a graph showing a temperature profile of the shipping package of Figure 1 according to Example 2.DETAILED DESCRIPTION

[0032] The present invention aims to address the limitations of the prior art by providing a shipping package that includes both a removable thermal unit and a PCM. Unlike traditional systems that rely on preconditioning the PCM, the disclosed configuration repositions the PCM as a passive thermal buffer, enabling precise temperature regulation. By using the PCM to moderate — rather than generate — thermal change, the system transforms a cost-intensive material into a stable insulator, eliminating the need for complex preconditioning.

[0033] The shipping package described herein comprises an inner envelope for containing the payload and an outer envelope for containing the inner envelope. The outer envelope is insulated, while the inner envelope is lined with PCM. Between the inner and outer envelopes, a removable thermal unit can be inserted. The removable thermal unitcan be frozen or heated separately from the shipping package before insertion between the inner and outer envelopes. Thus, the PCM is positioned between the payload and the removable thermal unit, moderating the cooling or heating effects of the removable thermal unit. Because the PCM is brought to its stabilization temperature by the removable thermal unit, the PCM itself does not need to be preconditioned. This configuration is ideal for keeping the payload at a stable temperature for a long period of time.

[0034] Figure 1 shows an example shipping package 100 that uses phase-change materials to control the temperature inside the package 100. The shipping package 100 may be used to transport payloads that are temperature sensitive and / or require temperature stability, particularly at temperatures lower than the surrounding environment. Examples of such payloads include drugs, pharmaceutical products or components, food, lab samples, medical supplies / materials, and similar. In this figure, the package 100 is shown closed.

[0035] The shipping package 100 includes an outer envelope 102. Most or all of the outer envelope 102 is double walled, with the outer wall being visible in Figure 1. In various examples, the space between the walls of the outer envelope 102 contains insulation to provide temperature control to the interior of the package 100. The outer envelope 102 may be generally rectangular, as depicted, or have another shape.

[0036] The outer envelope 102 is closed along two sides 104, 106 and a closed end 108 and further includes a closure 112 at an open end 110 that is closeable. The closure 112 may include a flap of envelope material with a permanent or semi-permanent closure mechanism, such as an adhesive strip, glue, a surface for applying adhesive or glue, or similar. The closure 112 may include a reusable closure mechanism, such as hook-and- loop strips (e.g., Velcro™), a grommet and string tie-off arrangement, a snap, or similar. Multiple of the same of different closure 112 may be used. For instance, in some examples, multiple adhesive strips may be provided to allow for limited reusability, in the sense that one adhesive strip is used for each use of the shipping package 100. In other examples, multiple closures 112 may be used to increase reliability and / or security. Toimprove the temperature stability of the package, the closure 112 may include a layer of insulation.

[0037] As shown in Figures 2A, the package 100 comprises the outer envelope 102 and an inner envelope 201. The outer envelope 102 includes an outer layer 200, and an inner layer 202, while the inner envelope 201 comprises an inner layer 203 and an outer layer 204. The layers 200, 202, 203, 204 may be formed from a sheet or sheets of thin flexible material, such as polyethylene, ethylene vinyl acetate, kraft paper, cardboard, or the like. An example laminate suitable for the outer envelope 102 is formed of layers of polyamide and polyethylene. The layers 200, 202, 203, 204 extend from a closed end 108 towards an open end 110 of the outer envelope 102. Near the open end 110, the inner layer 202 joins the outer layer 200. Hence, the outer envelope 102 is double walled except at the open end 110. The double wall of the outer envelope 102 may extend closer to or further from the open end 110 than depicted. Near the closed end 108, the inner envelope 201 may be joined or removably attached to the inner layer 202. The inner layer 203 and outer layer 204 of the inner envelope 201 may be joined at the closed end 108.

[0038] One or more layers 200, 202, 203, 204 may include an aperture configured to release air from the package 100 when compressed (not shown). In particular embodiments, the aperture(s) may be positioned adjacent to the open end 110.

[0039] The space between the outer layer 200 and inner layer 202 may be termed a first thermal control space 205. The space bounded by the inner envelope 201 and a relatively small portion of the outer layer 200 towards the open end 110, is a cavity or interior space 206 to hold a payload 208 being shipped. The space bounded by the outer envelope 102, the inner envelope 201 , and a small portion of the outer layer 200 towards the open end 100, is an intermediate space 209.

[0040] Turning now to Figure 2B, a front cross-sectional view of the shipping package 100 is shown along section line B-B. In this example, the layers 200, 202, 203, 204 are joined along the sides 106, 108. The inner layer 202 and outer layer 200 of the outer envelope 102 are joined along the sides 104, 106, thus dividing the first thermal control space 205 into two opposing cavities. Likewise, the inner layer 203 and the outer layer204 of the inner envelope 201 are joined along the sides 104, 106, dividing the second thermal control space 211 into a pair of opposing cavities. Furthermore, the inner envelope 201 is joined or removably attachable to the outer envelope 201 along the sides 104, 106. However, the layers 200, 202, 203, 204 are not necessarily joined along the sides. In particular, non-limiting examples, a pair of insulative sheets is positioned within the first thermal control space 205, along the sides of the outer envelope 102. This pair of insulative sheets can increase the volume of the intermediate space 209 and prevent heat transfer through the sides 106, 108. In addition (or instead), a pair of insulative sheets may be positioned within the second thermal control space 211 , along the sides of the inner envelope 201 . This pair of insulative sheets can increase the volume of the interior space 206 and prevent heat transfer through the sides 106, 108.

[0041] The shipping package 100 further includes phase-change material (PCM) in the form of a mat 210. The mat 210 is a generally flat, hollow body inside of which is phase-change material (PCM). The mat 210 may be a shell or bag of PCM. The mat 210 may include one or more interior cells that contain the phase-change material (as shown in further detail herein with respect to Figures 5 and 6). The mat 210 may be composed of recyclable material, such as polyethylene, polyamide, non-woven film, or similar materials, in the form of a single layer of material or laminates of the same or different materials. Any suitable number and configuration of PCM mats 210 may be used.

[0042] Examples of suitable PCM include water-based gels (e.g., super-absorbent polymer or SAP, carboxymethyl cellulose or CMC, etc.); paraffins; hydrated salts or other binary eutectic mixtures; linear alcohols; organic compounds derived from animal fat or plant oil (sometimes referred to as biobased materials); materials based on palm oil, palm kernel oil, rapeseed oil, coconut oil, or soybean oil; and similar materials. The PCM may include a viscosity-altering additive. The PCM may include an additive that makes it more flexible or pliable. The type and composition of PCM may be selected to achieve a desired cooling effect.

[0043] The shipping package 100 may further include a thermally insulative sheet 212 disposed within the first thermal control space 205. In this example, the thermallyinsulative sheet 212 is folded to have two legs 214 extend along the large sides of the envelope 102 and to have a bend 216 that is positioned at the closed end 108 of the envelope 102. In this example, the thermally insulative sheet 212 is generally rectangular to match the overall shape of the outer envelope 102 and has about twice the planar area of each of the PCM mats 210, so as to match their combined area. In other examples, two separate, thermally insulative sheets may be provided; one for each side of the envelope 102.

[0044] The thermally insulative sheet 212 may be flexible and may have resiliency. The thermally insulative sheet 212 may be shaped and sized with respect to the envelope 102 so that its flexible resiliency gives shape to the outer envelope 102. For example, the normal shape of the thermally insulative sheet 212 may be flat, so that when the sheet 212 folded the bend 216 urges the legs 214 to move away from each other and push against the outer layer 200 of the envelope thereby expanding the outer envelope 102 to its extents to give it shape. All or a portion of the thermally insulative sheet 212 may be rigid in order to provide structure to the shipping package 200.

[0045] By the same principle, the outer envelope 200 may resist the flexible resiliency of the thermally insulative sheet 212 to urge the side edges 218 of the legs 214 closer together. That is, the outer envelope 102 may be shaped and sized to constrain the tendency for the thermally insulative sheet 212 to unfold, which may urge the side edges 218 closer together to reduce what might otherwise be a larger gap in insulation.

[0046] The thermally insulative sheet 212 may be made of cellulose, rubber (natural or synthetic), foam, rubber, cotton, hemp, cardboard, bubble wrap, fiberglass, aerogel, fibrous materials, or similar materials. In examples where the thermally insulative sheet 212 comprises foam, the foam may be open-cell polyurethane foam, expanded polyethylene (EVE) foam, ethylene-vinyl acetate (EVA) foam, corn starch foam, plant fiber-based foam, or the like.

[0047] In the intermediate space 209, a removable thermal unit 220 may be inserted. The intermediate space 209 may be closable with a reusable closure mechanism to retain the removable thermal unit 220. Suitable closure mechanisms include hook-and-loopstrips (e.g., Velcro™), a grommet and string tie-off arrangement, a snap, or similar. The removable thermal unit 220 may comprise a container comprising a material for temperature control such as ice, gel, PCM, insulation, or the like. In specific non-limiting examples, the removable thermal unit 220 includes a water-based gel pack, a flexible ice blanket containing water, a PCM pack or mat, an instant heat pack utilizing an exothermic reaction of compounds such as magnesium sulfate and water or sodium acetate, or an instant cold pack utilizing an endothermic reaction involving ammonium nitrate, calcium ammonium nitrate, or urea with water. Since the intermediate space 209 is accessible via the closeable end 110, the removable thermal unit 220 can be removed for heating or cooling, separately from the package 100. When inserted into the intermediate space 209, the removable thermal unit 220 is disposed between the first thermal control space 205 and the second thermal control space 211 , and thus the thermal effect of the removable thermal unit 220 on the payload 208 is moderated by the PCM mat 210.

[0048] In this example, a PCM mat 210 is positioned within a second thermal control space 211 defined by the inner layer 203 and outer layer 204 of the inner envelope 201 along the large sides of the package 100. That is, in examples where the package 100 is generally rectangular, it has two large sides and at each of these sides, within the thermal control space 211 , is positioned the PCM mat 210. As such, in this example, a pair of opposing PCM mats 210 sandwich the interior space 206 and thus the payload 208 being shipped. In some examples, the second thermal control space 211 may further contain an insulative sheet 224 disposed one or both sides of the PCM mat. The insulative sheet 224 may comprise cellulose, rubber (natural or synthetic), foam, rubber, cotton, hemp, cardboard, bubble wrap, foil, fiberglass, aerogel, fibrous materials, or similar materials. In examples where the insulative sheet 224 comprises foam, the foam may be open-cell polyurethane foam, expanded polyethylene (EVE) foam, ethylene-vinyl acetate (EVA) foam, corn starch foam, plant fiber-based foam, or the like. All or a portion of the thermally insulative sheet 224 may be rigid in order to provide structure to the shipping package 200. In the non-limiting embodiment shown in Figure 2A, the insulative sheet 224 comprises a layer of bubble wrap disposed in the second thermal control space 211 adjacent to the outer layer 204 and the PCM mat 210. In this configuration, the insulativesheet 224 is positioned between the PCM mat 210 and the removable thermal unit 220 such that the insulative sheet 224 slows the heat transfer between the PCM mat 210 and the removable thermal unit 220, which improves the temperature stability of the payload 208. In embodiments that exclude the insulative sheet 224, inserting the removable thermal unit 220 may cause the PCM mat 210 to change phases, causing an abrupt temperature change.

[0049] PCM mats 210 and removable thermal units 224 used in the same package 100 may contain different types and / or compositions, so as to tune the performance of the package 100. Multiple mats 210 containing different PCM may be stacked together on one side of the interior space 206 to tune the performance of the package 100. In a given mat 210, different cells may have different PCMs. Moreover, in examples that include a pair of opposing PCM mats 210, each of the pair of PCM mats 210 may include different PCMs. The volume PCM contained in the PCM mat 210 and size of the removable thermal unit 220 may be selected according to the desired temperature profile of the payload. Furthermore, the conditioning of the removable thermal unit 220 may affect the performance of the package 100.

[0050] In a specific non-limiting example, the shipping package 100 is to hold the payload between 2 °C and 8 °C, the PCM mat 210 contains a PCM rated for about 5 °C, the insulative layer 224 is disposed between the PCM mat and the removable thermal unit 220, and the removable thermal unit 220 comprises a freezable gel- or water-based coolant that is conditioned at -20 °C prior to insertion in order to maintain the payload temperature between 2 °C and 8 °C. For greater clarity, the removable thermal unit 220 cools the package, while insulative layer 224 slows the heat transfer from the PCM mat 210 to the frozen thermal unit 220. The PCM is rated at 5°C, which stabilizes the temperature of the payload between 2 °C and 8 °C.

[0051] In another non-limiting example, the shipping package 100 is to hold the payload between about 2 °C and about 30 °C, and the PCM mat 210 contains a PCM rated for about 5 °C, and the removable thermal unit 220 comprises either a PCM rated for about 18 °C or about 23 °C. The package 100 is conditioned at room temperature,and the removable thermal unit 220 is conditioned either at room temperature or below.

[0052] In a further non-limiting example, the shipping package 100 is to hold the payload between about 15 °C and about 25 °C, and the PCM mat 210 contains a PCM rated for about 18 °C, and the removable thermal unit 220 comprises a PCM rated for about 23 °C. The package 100 is conditioned at room temperature, and the removable thermal unit 220 is conditioned either at room temperature or below.

[0053] In yet another non-limiting example, the shipping package 100 is to hold the payload below 0 °C, and the PCM mat 210 contains a PCM rated for about -5 °C, and the removable thermal unit 220 comprises a PCM rated for about -20 °C.

[0054] Edges of the inner envelope 201 and the outer envelope 102 may be heat sealed, bonded with glue or adhesive, or otherwise joined. The PCM mats 210 and thermally insulative sheet 212 may be positioned with respect to a sheet of material being used to form the inner envelope 201 or the outer envelope 102 prior to joining edges of the material, so that the PCM mats 210 and thermally insulative sheet 212 are permanently enclosed within the respective thermal control spaces 205, 211 .

[0055] In operation, the shipping package 100 may be placed in an environment, such as a refrigerator, cooler, or freezer, that causes exothermic phase change (e.g., freezing) of the PCM in the mats 210. Then, a payload 208 to be shipped is inserted into the interior space 206 of the shipping package 100 and the closure 112 is closed. The shipping package 100 is then transported to the destination. During transport, the PCM in the mats 210 undergoes endothermic phase change (e.g., it melts) to regulate the temperature of the interior space 206 and payload 208 contained therein. That is, environmental heat, which might otherwise warm the payload 208, is instead absorbed by the PCM mats 210. Once the shipping package 100 arrives at its destination, the closure 112 may be opened and the payload 208 removed. The shipping package 100 may then be reused provide that the closure 112 enables reuse.

[0056] For added protection, during operation, the shipping package may be inserted into a protective envelope, cardboard box, or plastic box or may be shrink-wrapped withplastic film. Such outer protection may be replaced after each use or may be reusable. For example, a protective envelope or shrink-wrapping may be replaced after each use, while a box may be reused.

[0057] Figure 3 shows the shipping package 100 when open. As can be seen, in this example, the closure 112 includes a flap 300 of envelope material and an adhesive strip 302 attached to the flap 300. To close the package 100, the flap 300 may be folded over the open end 110 and the adhesive strip 302 adhered to the outside of the outer envelope 102 (see Figure 1). To open the package 100, the flap 300 may be pulled to detach the adhesive strip 302 from the outside of the outer envelope 102.

[0058] Figure 4 shows another example shipping package 400. Features and aspects of the package 400 may be the same as the package 100 with only differences discussed in detail here.

[0059] The shipping package 400 includes multiple closures to permit limited reuse. Each closure includes an adhesive strip 402, 404 serially arranged on a flap 300 of envelope material. Each adhesive strip 402, 404 functions in the same manner as the adhesive strip 302 discussed above with respect to Figure 3. One adhesive strip 402, 404 may be used each time the package 400 is used to ship a product. Accordingly, the number of reuses is the same as the number of adhesive strips 402, 404, which in this example is two. In other examples, other numbers of adhesive strips 402, 404 or other types of multiple closures may be used.

[0060] Lines of perforations 406 may be provided between adhesive strips 402, 404 to allow for easy opening of the package 400 and to facilitate reuse. For example, an adhesive strip 402 closest to the end of the flap 300 may be used to seal the package 100 for the first use. Then, to open the package 100, the line of perforations 406 adjacent the strip 402 may be broken, thereby separating the strip 402 from the flap 300 and allowing the flap 300 to open, while the strip 402 remains adhered to the outside of the outer envelope 102. This process may be repeated to consume all the adhesive strips 402, 404 (or other closures) provided.

[0061] Limited reuse of the packages, as discussed herein, reduces waste compared to a single-use package, while also ensuring that the packages remain fit for purpose. The useable life of a package can be limited by the number of serial closures provided to the package. It is contemplated that various implementations of the packages discussed herein will have different amounts of closures depending on the specific applications intended. For example, packages for critical applications, such as medicine delivery, may be limited to one or two uses, while packages used for food delivery may be limited to four or five uses.

[0062] Figures 5A to 6 show examples of PCM mats 201 a, 210b, 210c, 21 Od (generically referred to herein as “PCM mat 210”) useable with the packages discussed herein. The PCM mat 201 a, 210b, 210c, 21 Od may include two layers of material that are bonded (e.g., heat sealed) at certain regions to form borders of cells and that are left unbonded at other regions to form the cells themselves to contain PCM. While not particularly illustrated in the Figures, the removable thermal unit 220 may be similarly configured with any suitable number of cells.

[0063] As shown in Figure 5A, a PCM mat 210a has a bonded perimeter 502 and three linear regions 504 of bonded material that extend (e.g., horizontally) between opposing points on the perimeter 502 to form four rectangular cells 506 that contain PCM. Owing to their lack of PCM, the bonded regions 504 may allow for the mat 210a to flex and therefore conform to the shape of the package.

[0064] As shown in Figure 5B, a PCM mat 210b has a bonded perimeter 512, three linear regions 514 of bonded material that extend (e.g., horizontally) between opposing points on the perimeter 512, and one linear region 518 of bonded material that extends in a perpendicular direction (e.g., vertically) between opposing points on the perimeter 512. The bonded regions 514, 516 thus form a two-by-four grid of cells 516 that contain PCM. Owing to their lack of PCM, the bonded regions 514, 516 may allow for the mat 210b to flex in two dimensions and therefore conform to the shape of the package.

[0065] As shown in Figure 5C, a PCM mat 210c has a bonded perimeter 522, three linear regions 524 of bonded material that extend (e.g., horizontally) between opposingpoints on the perimeter 522, and two linear regions 528 of bonded material that extend in a perpendicular direction (e.g., vertically) between opposing points on the perimeter 522. The bonded regions 524, 528 thus form a three-by-four grid of cells 526 that contain PCM. Again, owing to their lack of PCM, the bonded regions 524, 528 may allow for the mat 210c to flex in two dimensions and therefore conform to the shape of the package.

[0066] As shown in Figure 6, a PCM mat 21 Od has a bonded perimeter 602, one linear region 604 of bonded material that extends (e.g., horizontally) between opposing points on the perimeter 602, and one linear region 606 of bonded material that extends in a perpendicular direction (e.g., vertically) between opposing points on the perimeter 602. The bonded regions 604, 606 thus form a two-by-two grid of cells 608 that contain PCM. Due to the limited number of bonded regions 604, 606, the two-by-two PCM mat 21 Od can house more PCM than a mat with the same outer dimensions but more bonded regions (e.g., mats 210b, 210c). Temperature stability is improved by increasing the volume of PCM in the mat. Thus, the two-by-two cell configuration optimizes both flexion and PCM volume.

[0067] As mentioned above, the mats selected for a package may have different PCM to tune performance. Similarly, different cells of a given mat may have different PCM to tune performance. In some examples, two or more types of PCM may be included in alternating cells of the PCM mat 210.

[0068] PCM used for a given package may be selected based on the required performance of the package, which may depend on the season. The same applies to the thermally insulative sheet 212, the insulative layer 224, and the removable thermal unit 220. The term “season” is used herein to denote different periods of time with different environmental conditions, not only the conventionally known seasons. For example, during the summer, products may be more susceptible to overheating when compared to other times. It may be useful to select different PCMs and / or insulation for service during different times of year. It may also be useful to keep a stockpile of packages on hand to readily ship products. In some examples, a water-based gel is provided for use as the removable thermal unit 220 in a “summer” shipping package. The water-based gel matmay be divided into fewer cells, and in non-limiting examples, the water-based gel mat is subdivided into a 1 -by-4, 2-by-3 or a 2-by-2 configuration, as shown in Figure 6. Minimizing the number of cells optimizes the volume of water-based gel provided in each mat, thus improving the cooling power. Since water-based gel is flexible, the mat retains its flexibility in the shipping package. In further non-limiting examples, a flexible ice blanket is provided for use as the removable thermal unit 220 in a “winter” shipping package. The ice blanket may be divided into a greater number of cells to compensate for the rigidity of ice, and in particular non-limiting examples, the ice blanket is subdivided into a 3-by-5 or 4-by-4 configuration. The subdivision reduces the amount of ice provided in the ice blanket, which is suitable in circumstances when overcooling the payload is a risk. Generally, less cooling is required for shipping in cold weather. Since the thermal units 220 are removable, the same shipping package 100 may be used in both winter and summer by simply inserting a suitable removable thermal unit 220 into the intermediate space 209.

[0069] Accordingly, a shipping package as discussed herein may be provided with an indicator of the contained PCM and / or insulation. Such an indicator may indicate whether the package is intended for winter, spring, summer, or autumn service, for example. Example indicators include a sticker on the envelope, a color of the envelope, a text label on the envelope, and so on. PCM mats, removable thermal units, and thermally insulative sheets may also be given the same or similar indicator to facilitate maintenance and / or manufacture of packages. For example, envelopes, PCM mats, removable thermal units, and / or thermally insulative sheets may be provided in sets of colors with the intention that like colored components are to be used together. For example, blue, grey, and white components may be used to indicate three seasons, and differently configured envelopes, PCM mats, removable thermal units, and / or thermally insulative sheets may be provided in those colors.

[0070] While the shipping package 100 has been described above with respect to the seasons, it should be understood that other variations are contemplated. The shipping package 100 may be customized for any suitable number of environmental conditionsincluding climate zones, transit time, transportation conditions, warehouse conditions, and product sensitivity to temperature fluctuations.

[0071] In view of the above, it will now be apparent that variants, combinations, and subsets of the foregoing embodiments are contemplated. For example, while the shipping container was discussed above in relation to a specific combination of removable thermal units and PCM mats, other combinations are contemplated. In one example, a gel- or water-based thermal pack is contained in the second thermal-control space 211 , and a PCM mat is insertable into the intermediate space 209. In another example, a gel- or water-based thermal pack is contained in the second thermal-control space 211 and another gel- or water-based thermal is insertable into the intermediate space 209. In one example, a PCM mat is contained in the second thermal-control space 211 , and another PCM mat is insertable into the intermediate space 209.

[0072] The shipping package 100 is not particularly limited to two opposing PCM mats 210, and more PCM mats 210 may be included in the second thermal control space 211. In some examples, the second thermal control space 211 includes two PCM mats 210 on opposite sides of the payload 208. Additional layers of insulation may be sandwiched between the PCM mats 210.

[0073] In another variant, the shipping envelope 100 includes more than one inner envelope 201. The inner envelopes 201 may be nested within each other, or the inner envelopes 201 may be stacked side-by-side within the outer envelope 102.

[0074] In a further variant, the shipping envelope 100 includes a protective enclosure. The protective enclosure may comprise a sleeve, envelope, box or other container to protect the outer envelope 102 from wear. The protective enclosure may comprise any suitable material such as paper, cardboard, or plastic. Generally, the protective enclosure does not include insulative or thermal layers and thus is less resource-intensive to replace than the outer envelope.

[0075] It should be understood that the shipping package described above provides a number of advantages over the prior art.

[0076] First, it enables cost-effective thermal regulation by reducing the dependence on expensive phase change materials (PCMs). The strategic placement of the PCM between the payload and the removable thermal unit allows the PCM to function effectively as a thermal buffer, thereby mitigating the risk of overcooling or overheating sensitive contents. This is achieved without requiring direct preconditioning of the PCM, as the removable thermal unit is separately conditioned and subsequently inserted into the package.

[0077] Second, the removable thermal unit requires substantially less freezer space compared to conventional systems that necessitate freezing the entire package or large PCM components. This improves operational efficiency and storage logistics.

[0078] Third, the modularity of the system allows for the substitution of different removable thermal units adapted to various ambient conditions, thereby eliminating the need to alter the packaging configuration or preconditioning protocol seasonally. This significantly reduces complexity in logistics and assembly.

[0079] Fourth, the combination of the insulated outer envelope, the PCM-lined inner envelope, and the intervening removable thermal unit enables prolonged thermal stability of the payload, maintaining target temperature ranges over extended durations without active cooling or heating mechanisms.

[0080] Finally, the shipping envelope reduces waste associated with cold chain technologies since select layers can be replaced or reused as needed. For example, the inner and outer envelopes can be reused if a resealable closure is included at the open end. Furthermore, the outer envelope 102 may deteriorate more quickly than the inner envelope and can be replaced while reusing the inner envelope 201 . Additionally, the protective enclosure can reduce wear and increase the lifespan of the outer envelope 102.

[0081] It should be recognized that features and aspects of the various examples provided above can be combined into further examples that also fall within the scope of the present disclosure. In addition, the figures are not to scale and may have size andshape exaggerated for illustrative purposes.EXAMPLE 1

[0082] In one example, the temperature profile of a shipping package according to the present specification was compared to that of an insulated envelope according to the prior art. The prior art insulated envelope generally comprises a mailer lined with bubble wrap and a single cavity for containing both the frozen gel and the payload. Thus, the frozen gel is adjacent to the payload.

[0083] The insulated envelope tested in Example 1 was a large mailer containing two 8"x8" 24oz flexible gels, and a Uline™ bubble wrap sleeve.

[0084] The shipping envelope 100 tested in Example 1 was a large PCM5 mailer. The removable thermal units 220 were two frozen, 26oz gel mats positioned in the intermediate spaces 209. The PCM mats 210 were selected to have a phase change temperature of approximately 5°C. The insulative sheets 224 were 5mm EPE foam sheets.

[0085] The results of Example 1 are displayed in Figure 7 which shows a graph of temperature (°C) plotted against time (hours).

[0086] Both the insulated envelope and the shipping package 100 were subjected to ambient temperatures between 25 °C and 30 °C. The ambient temperature is shown in Figure 7 at the solid line. Temperature sensors recorded the temperature of the respective payloads in each of the insulated envelope and the shipping package 100. The temperature of the payload in the insulated envelope is shown at the dot-dash line in Figure 7. The temperature of the payload in the shipping package 100 is shown at the dashed line in Figure 7.

[0087] The insulated envelope failed to maintain the temperature of the payload within the desired range of 2 °C to 8 °C. Since the frozen gel is provided in the same cavity as the payload, the temperature of the payload initially decreased to about -5 °C. Once the frozen gel melted, the temperature of the payload quickly increased above the desired temperature range. Within 12 hours, the payload surpassed 8 °C.

[0088] The shipping package 100 on the other hand, maintained the temperature of the payload stably within the desired range for about 27 hours. In the shipping package 100, the payload 208 is separated from the removable thermal units 220 by PCM mats 211 which moderate the cooling effect on the payload 208.EXAMPLE 2

[0089] In another example, the temperature profile of a shipping package according to the present specification was compared to that of an insulated envelope containing PCM. The insulated envelope generally comprises a mailer lined with insulation and a mat containing a PCM with a phase change temperature of 5°C. Thus, the PCM mat is adjacent to the payload.

[0090] The prior art PCM envelope tested in Example 2 was a medium mail containing a PCM mat with a phase change temperature of about 5°C. The prior art PCM envelope was preconditioned at -21 °C for 24 hours, then +5°C ±3°C for 27h.

[0091] The shipping package 100 tested in Example 2 was a large PCM 5 mailer. The removable thermal units 220 were two frozen, 26oz gel mats positioned in the intermediate spaces 209. The PCM mats 210 contained a PCM selected to have a phase change temperature of approximately 5°C. The insulative sheets 224 were 5mm EPE foam sheets.

[0092] The results of Example 2 are displayed in Figure 8 which shows a graph of temperature (°C) plotted against time (hours).

[0093] Both the insulated PCM envelope and the shipping package 100 were subjected to ambient temperatures between 25 °C and 30 °C for a period of 40 hours. The ambient temperature is shown in Figure 8 at the solid line. Temperature sensors recorded the temperature of the respective payloads in each of the insulated PCM envelope and the shipping package 100. The temperature of the payload in the insulated PCM envelope is shown at the dot-dash line in Figure 8. The temperature of the payload in the shipping package 100 is shown at the dashed line in Figure 8.

[0094] The insulated envelope with PCM maintained the temperature of the payloadwithin the desired range of 2 °C to 8 °C for less than eight hours. Once the PCM mat melted, the temperature of the payload quickly increased above the desired temperature range. The shipping package 100 on the other hand, maintained the temperature of the payload stably within the desired range for about 27 hours.

Claims

CLAIMSWhat is claimed is:1 . A shipping package comprising: an outer envelope having a closed end and a closeable end, the envelope defining a first thermal control space; a first insulative sheet positioned within the first thermal control space; an inner envelope disposed within the outer envelope, the inner envelope defining a second thermal control space and an interior space that is separate from the first and second thermal control spaces, wherein the interior space is configured to contain a payload; an intermediate space defined by the inner envelope and the outer envelope, the intermediate space separate from the first thermal control space and the second thermal control space and configured to receive a removable thermal unit therebetween; and a phase-change material mat positioned within the second thermal control space for moderating thermal effects of the removable thermal unit.

2. The shipping package of claim 1 wherein the phase-change material mat is permanently sealed within the second thermal control space, and the first insulative sheet is permanently sealed within the first thermal control space.

3. The shipping package of claim 2 further comprising a second insulative sheet permanently sealed within the second thermal control space and positioned to insulate the phase-change material mat from the removable thermal unit.

4. The shipping package of claim 3 further comprising a third insulative sheet permanently sealed within the second thermal control space and positioned to insulate the phase-change material mat from the payload.

5. The shipping package of claim 3 wherein the second insulative sheet is selected from foam, foil, bubble wrap, fiberglass, aerogel, and fibrous materials.

6. The shipping package of claim 5 wherein the second insulative sheet is selected from open-cell polyurethane foam, expanded polyethylene (EVE) foam, ethylene-vinyl acetate (EVA) foam, corn starch foam, and plant fiber-based foam.

7. The shipping package of claim 2 wherein the first insulative sheet is selected from: cellulose, rubber (natural or synthetic), foam, rubber, cotton, and hemp.

8. The shipping package of claim 7 wherein the first insulative sheet is selected from open-cell polyurethane foam, expanded polyethylene (EVE) foam, ethylene-vinyl acetate (EVA) foam, corn starch foam, and plant fiber-based foam.

9. The shipping package of claim 2 wherein the phase-change material has a phasetransition temperature selected to correspond to a target temperature for the payload.

10. The shipping package of claim 2 further comprising a resealable closure at the closeable end for closing the outer envelope.

11. The shipping package of claim 10 wherein the inner envelope is removably attached to the outer envelope.

12. The shipping package of claim 2 wherein the phase-change material mat includes a plurality of cells for containing phase-change material.

13. The shipping package of claim 12 wherein the plurality of cells includes a plurality of phase-change materials having different phase-transition temperatures.

14. The shipping package of claim 2 further comprising a protective enclosure selected from an envelope, box, sleeve, and wrap.

15. The shipping package of claim 2 further comprising a fourth insulative sheet positioned within the first thermal control space at the sides of the shipping package.

16. The shipping package of claim 1 further comprising one or more non-flexible insulative sheets for providing structure to the shipping package.

Images