Tableware containing microwave-activatable phase change material - Patents.com

Abstract

In a dinnerware (100) containing a phase change material mixture, the phase change material mixture includes one or more organic phase change materials selected from the group of organic acids, organic alcohols, and organic esters, and one or more organic microwave susceptors selected from the group of glycols, the phase change material mixture is contained in a plastic package (120), the phase change material mixture is placed under a central portion of the dinnerware where food is intended to be placed and is not placed under an edge portion of the dinnerware where no food is present and where the dinnerware is intended to be handled, and the phase change material mixture can be melted by microwave irradiation.

Description

[Technical field]

[0001] The present invention relates to a tableware comprising a phase change material mixture that is activatable by microwave radiation.The present invention further relates to a method of manufacturing and using a tableware comprising a phase change material mixture suitable for keeping food warm, wherein a phase transition of the phase change material mixture from a solid state to a liquid state can be achieved under the influence of microwave radiation. [Background technology]

[0002] Several patents are known regarding the application of phase change materials contained in tableware to keep food cold or hot, which is achieved by the potential energy that can be activated by the respective solidification or melting of the phase change material and then transferred to the target food to be kept cold or hot after the activation of the phase change material.

[0003] For applications for keeping food warm, the necessary activation or phase transition (from solid to liquid state) is typically achieved by placing the dish containing the phase change material, which typically has a melting point in the temperature range of 50-80° C., in an environment at a temperature higher than the melting point of the phase change material. Thus, a heating cabinet at a temperature of 90° C. or an oven set at a temperature of 120° C. is typically suitable for melting a phase change material, for example, having a melting point of 70° C.

[0004] Nevertheless, the time required for the phase change is relatively long, depending on the potential energy of the phase change material and the amount of phase change material. For example, a phase change material with a melting point of 75° C. may take more than 90 minutes to complete the phase change at an ambient temperature of about 90° C. (as in a normal heating cabinet). This long time required to activate such tableware containing phase change material is an inherent drawback for use by both private and professional users.

[0005] Others are known which are phase change materials activatable by microwave radiation, for example based on sodium acetate trihydrate, which has a melting point of 58° C., or composite materials based on material mixtures, for example based on a combination of a phase change material with expanded graphite, as described for example in US Pat. No. 9,765,201 (B2). However, all the above-mentioned known microwave activatable phase change materials have certain drawbacks, such as for example an inappropriate melting point or difficult manufacturing methods, or the risk of electrical discharges with potential fire risks during use.

[0006] Another problem that arises when (pre-)heating dishes in a microwave oven is that the edges of plates, dishes and bowls can become too warm or too hot to handle by hand without a protective material, e.g. an oven glove, while the central part of the dish (on or in which food is placed) is still insufficiently warm to keep the food placed in that part of the dish warm. Summary of the Invention

[0007] What is lacking in the prior art is a dish containing a phase change material that has a suitable melting point for keeping food warm and that can be rapidly (within a few minutes) activated by microwave irradiation (this is a phase transition from a solid state to a liquid state), such that the central portion of the dish (the surface for serving food and the cavity below this surface in which the microwave activatable phase change material is located) heats up sufficiently rapidly under the influence of microwave irradiation (while the phase change material melts) and the edge portions of the dish (which must be handled by the user) remain sufficiently cool so that they can be handled without the need for protective materials.

[0008] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to provide a solution to at least some of the problems and limitations mentioned above.

[0009] In a first aspect, the present invention relates to a tableware comprising a microwave activatable phase change material according to claims 1 to 15. In a second aspect, the present invention relates to a method of using a tableware comprising a microwave activatable phase change material according to claims 16 to 30. In a third aspect, the present invention relates to a method of producing a tableware comprising a microwave activatable phase change material according to claims 31 to 45. [Brief description of the drawings]

[0010] The above, below, and other advantageous features and objects of the present invention will become more apparent and the invention will be better understood based on the following detailed description when read in conjunction with the accompanying drawings, tables, and graphs. [Figure 1] 1 illustrates an exemplary embodiment of a part of a food container according to the present invention, the part including a phase change material contained in a hollow space or cavity formed by the food container. [Diagram 2] FIG. 2 shows a single container assembled from the parts shown in FIG. 1. [Diagram 3] 1 is a table showing the measurement results for Example 2. [Figure 4] 11 is a table showing the measurement results for Example 3. [Diagram 5] 11 is a table showing the measurement results for Example 4. [Figure 6] 11 is a table showing the measurement results for Example 5. [Figure 7] 13 is a table showing the measurement results for Example 6. [Figure 8] 13 is a table showing the measurement results for Example 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention relates to a new tableware 100, which includes a phase change material 120 housed in a hollow space or cavity of the tableware 100. As shown in Figures 1 and 2, the hollow space or cavity is preferably formed by an upper part 110 and a lower part 130 attached or assembled to each other. The tableware 100 is suitable for keeping food and / or beverages warm, and the phase change material 120 can be activated by microwave radiation, as in a conventional microwave oven. The phase change material is advantageously located under the tableware surface on which the food to be kept warm is placed. After activation by microwave radiation, which causes a phase transition of the phase change material from a solid state to a liquid state, the edge portion 111 of the tableware, which is used to manually remove the tableware 100 from the microwave oven, remains cooler than the central portion 112 on which food can be placed, and is preferably cool enough to handle without the need to utilize protective materials such as oven gloves.

[0012] The present invention also relates to a new phase change material mixture, which is an organic phase change material, preferably an organic acid, an organic alcohol or an organic ester, such as behenyl behenate, or a combination of such phase change materials, and an organic microwave susceptor or a combination of such organic microwave susceptors, preferably a glycol, a combination of microwave susceptors, preferably a glycol, such as monopropylene glycol and / or dipropylene glycol, which forms a substantially homogeneous or even homogeneous mixture in both liquid and solid phases, even after successive melting and solidification cycles and then after first mixing in the liquid state to obtain a mixture, and the content of microwave susceptor(s) in the mixture of phase change material and microwave susceptor is preferably at most 2.5-25% by weight, more preferably at most 5-15% by weight, even more preferably at most 7.5-12.5% ​​by weight. More preferably, the phase change material mixture comprises an organic ester as the phase change material, even more preferably behenyl behenate, and even more preferably dipropylene glycol as the microwave susceptor, since they form a homogeneous liquid mixture after mixing in the above mentioned proportions and also after successive cycles of solidification and melting. Even more preferably, this phase change material mixture comprising behenyl behenate and dipropylene glycol is substantially free of water. "Substantially free of water" is understood to mean that the phase change material mixture comprises less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight of water. The presence of water leads to heterogeneity due to separation after successive cycles of solidification and melting. Another disadvantage of the presence of water is the risk of transesterification and therefore indirectly the instability of the phase change material function of the phase change material mixture. In the case of phase change material mixtures comprising water, in application tests, separation of water from the phase change material mixture was further detected by the observation of undesirable hot zones (specifically with an increase in water content) upon exposure to microwave irradiation. A similar risk arises when the phase change material mixture includes a combination of an organic acid, an organic alcohol, and water, which can result in an unstable composition of the phase change material mixture due to the possibility of esterification and further separation of any water present.

[0013] Such a phase change material mixture can be prepared by mixing with stirring at a (process) temperature higher than the melting point of the materials to be mixed, preferably 20-40° C. higher than the melting point of the phase change material.

[0014] The melting point of the organic phase-change material is preferably in the range of 30 to 120°C, more preferably in the range of 50 to 90°C, and further preferably in the range of 65 to 80°C.

[0015] The organic phase change material preferably has a boiling point and a flash point greater than 150°C, more preferably greater than 200°C, even more preferably greater than 250°C.

[0016] The organic microwave susceptor preferably has a boiling point and a flash point that is at least 25° C. higher than the melting point of the phase change material, more preferably at least 35° C. higher than the melting point of the phase change material, and even more preferably at least 45° C. higher than the melting point of the phase change material.

[0017] After mixing, the molten phase change material mixture can be poured into a container, which can then be solidified in the container, thereby obtaining the phase change material mixture in a specific solidified shape. The container required for this purpose can consist of a receptacle, but can also be formed for example by a ring of metal, preferably aluminum or an aluminum-containing alloy, placed on a plate that can be cooled, preferably a coolable metal plate of stainless steel or aluminum. Alternatively, the phase change material mixture can be pressed into the receptacle in an at least partially solidified state to give it a specific shape.

[0018] The invention also relates to the packaging of a solid phase change material mixture of a particular shape (comprising one or more organic phase change materials and one or more organic microwave susceptors) in a casing, for example a plastic casing constructed from two separate, optionally heat-stabilized (BO)PET films: an upper film and a (deep-drawn) lower film that are welded together, for example using thermal welding, or also for example by ultrasonic or laser welding.

[0019] In addition to packaging with the above mentioned films, the present invention also relates to placing the developed phase change material mixture in another rigid package, for example in a hollow space or cavity formed by a rigid material such as plastic (for example SPS or syndiotactic polystyrene, or (high density) polypropylene), glass (for example tempered glass), stoneware, porcelain, etc., to obtain tableware, for example a double-walled cup or a double-walled drinking utensil. Materials characterized by low absorption of microwave radiation are preferably used as rigid packaging, especially for the part of the tableware that is placed on and in contact with, for example, a table.

[0020] The invention also relates to the addition of other materials to the phase change material mixture to obtain new materials that maintain their solid form above the melting point of the phase change material mixture, for example by adding polymer-based compositions or by mixing in materials with a high melting point, for example above 125° C., preferably above 150° C., more preferably above 175° C., even more preferably above 200° C., for which waxes based on polyethylene and polypropylene are options. The materials for this addition to achieve a solid form over the entire phase transition cycle preferably do not have thermal insulating properties and are therefore preferably characterized by a thermal conductivity of at least 0.2 W / m·K.

[0021] The invention also relates to placing a (plastic) casing filled with a phase change material mixture, with a total amount of the phase change material mixture between 10 and 2000 g, in a (dish) cavity formed by a lower and upper plate or a lower and upper dish (or another whole or other combination of lower and upper parts, or another whole or other combination of inner and outer parts), optionally by assembling with a variant of upper and lower parts, optionally of different choices of plastic, porcelain, glass, metal, or other material, through optionally gluing a top film of the (plastic) casing containing the phase change material mixture to the underside of the upper part, and then gluing and optionally sealing the upper part to the lower part of the whole plate or dish, which may be made of plastic, porcelain, glass, metal, or other material.

[0022] The invention also relates to the use of a dish containing a packaged phase change material mixture in a microwave oven by placing the dish in a microwave oven and activating it for 1 to 12 minutes at 250-1250W, for example for a single regular (dinner) plate on which e.g. 50g of phase change material mixture is placed, for example for 3 minutes at 600-1000W, for example for a larger (serving) dish (with a larger amount of phase change material mixture, e.g. 100 or 150g) at 600-1000W, for example for 5 minutes, or for a stack of 6 dinner plates (e.g. 6 x 50g of phase change material mixture) at 600-1000W, for example for 6 minutes.

[0023] During this period of exposure to microwave radiation, the phase change material mixture melts, due to the generation of heat due to the presence of the microwave susceptor, and the center of the dish is also heated, but the edge parts heat up less quickly and can continue to be handled due to their lower temperature than the center part. For example, if the phase change material mixture is more than 90-95% melted and the temperature of the center part is around 80-100°C (for a dinner plate containing, for example, 50 g of phase change material mixture with a melting point of, for example, 70-75°C, after, for example, 3-4 minutes at 800 W), then for the edge parts, the temperature is then below 70°C, or even below 60°C.

[0024] For (dinner) plates and (serving) dishes without a phase change material mixture disposed thereon, the edge parts warm up in a microwave oven at the same rate as, and even more rapidly than, the center parts under corresponding conditions of microwave activation. This is a known problem in heating plates in a microwave oven, where the edges of dinner plates and serving dishes become too warm or even hotter. For a normal dinner plate, after 4 minutes in a microwave oven at 800 W, for example, a temperature of less than 45° C. was determined in the center and a temperature of more than 75° C. was determined in the edge parts. For a dinner plate consisting of a normal upper plate and a lower plate attached thereto, after 4 minutes in a microwave oven at 800 W, for example, a temperature of less than 60° C. was measured in the center and a temperature of more than 70° C. was observed in the edge parts.

[0025] This determination that the temperature of the edge portion of the regular plate was much higher than that of the edge portion of a similar plate containing a microwave activatable phase change material mixture under the same conditions of exposure to microwave radiation was not consistent with the expectation that the presence of the microwave activatable phase change material mixture would cause the entire plate, and thus the edge and center portions, to heat up more rapidly compared to a regular plate not containing the microwave activatable phase change material mixture. It is noteworthy that the plate containing the microwave activatable phase change material mixture reaches a significantly lower temperature at the edge portion than the regular plate after exposure to identical microwave radiation in terms of power and time.

[0026] When (dinner) plates and (serving) dishes are heated in a normal oven or heating cabinet (e.g. at 90 or 120°C for 30-120 minutes), the same problems with the edges becoming too hot and unable to be handled without protective equipment occur, with the various parts of the dish becoming similarly hot, and therefore with the same measurements of the edges being too warm or even hot. At the above mentioned residence times in the oven and heating cabinet, the temperatures were determined for the centre and edges, which were close to the set temperature of the oven and heating cabinet, where similar temperatures were observed for the centre and edges of the (dinner) plates and (serving) dishes.

[0027] The present invention also relates to the application of adhesives that are thermally conductive and / or include microwave susceptors, and by using such adhesives to adhere a packaged phase change material mixture to the underside of a surface to be kept warm (e.g., a dinner plate or serving dish), the time required for the packaged phase change material mixture to melt under exposure to microwave radiation can be reduced by more than 30 seconds, or even more than 60 seconds.

[0028] The present invention provides the technical effect that by placing a (packaged) phase change material mixture within a dish in combination with microwave activation (for phase transition from solid to liquid state), it is possible to heat (dinner) plates and (serving) dishes and activate the phase change material function, thereby allowing the central portion of the plate or dish to be maintained at a higher temperature than a determined temperature (e.g. 50°C), for example for more than 30 to 45 minutes, and therefore also allowing food placed on the central portion to be maintained at a temperature of e.g. 50°C, while the edges of the plate are initially cool enough to handle, e.g. initially below 60°C or even below 50°C.

[0029] The durability of the phase change material mixture and the dishware containing the packaged phase change material mixture is also demonstrated by performing cycle testing. This is determined by observing a stable required melting time in a microwave oven and determining a stable warming time after the dishware is removed from the microwave oven and food is placed on it. This is determined using temperature sensors and infrared thermometers. This is also done on the dishware, for dinner plates and serving dishes, both on the dishware itself and on the food placed on the dishware, as well as for soup bowls and coffee cups. This observation of stable melting and warming times indicates the stability of the functionality of the phase change material and therefore the stability of the durability of the phase change material mixture after successive phase transition cycles of the phase change material mixture, i.e., successive cycles of melting and solidifying the phase change material mixture.

[0030] Thus, in addition to the applications in the above mentioned products such as dinner plates and serving dishes, the present invention also relates to applications in products such as (soup) bowls, (coffee) mugs, (drinking) cups, etc.

[0031] The present invention will now be described with reference to non-limiting examples which are illustrative of the present invention, but these examples are not intended to limit the scope of the present invention and should not be construed as limiting the scope of the present invention.

[0032] For the advantages and technical effects of the elements described in the following embodiments, reference is made to the advantages and technical effects of the corresponding elements described above in the detailed description. EXAMPLES

[0033] A phase change material having a melting point of 74° C., in this example CrodaTherm 74, which is not functionally microwave activatable, is heated to about 90° C. in a mixing vessel while stirring and maintained at about 90° C. From the moment the phase change material is melted, a microwave susceptor, in this case dipropylene glycol, is added in a ratio of 90% phase change material and 10% microwave susceptor by weight to obtain a microwave activatable phase change material mixture.

[0034] After sufficient mixing time, for example 30 minutes at 90°C, the phase change material mixture is pumped and poured into a 10-180g circular aluminum ring with a diameter of 20-300 mm that is placed on a coolable plate, specifically an aluminum ring with a diameter of 130 mm in this example.

[0035] The phase change material mixture is pumped into the ring in a molten state, and a mass of 60 g is applied to the aluminum ring. The aluminum ring with the solidifying phase change material mixture is cooled until sufficient or complete solidification is achieved. Sufficient solidification is understood to mean that the phase change material mixture is solidified to such an extent that it can be moved or handled in a simple manner.

[0036] Before being placed in the dish, the disc-shaped phase change material mixture is packaged in a plastic casing based on (BO)PET film, such as Hostaphan RHST.

[0037] The plastic package consists of two layers of film, the bottom film of which is thermally preformed using vacuum to create a recess 130 mm in diameter and 5 mm thick, creating a space for placing the phase change material mixture.

[0038] Next, the solidified phase change material mixture having a specific shape is placed into the space formed above. Then, the top film is placed, and then the bottom film and the top film are thermally double welded together at a temperature of 175°C.

[0039] During heat welding, a vacuum is also created within the plastic package containing the phase change material mixture. The absence of air provides better contact between the phase change material mixture and the surface on which the food is placed to be kept warm, which allows for improved thermal conductivity and transfer.

[0040] After welding, the packaged phase change material mixture is mechanically cut from the double film roll. In this way, a plastic package is formed with a diameter of about 20 mm larger than the diameter of the disk made of the packaged phase change material mixture. In this example, a plastic package made of (BO)PET film containing the phase change material mixture and with a diameter of 150 mm was used.

[0041] In the following, the steps of the manufacturing method for the assembled plate 100 are described. Figure 1 shows an upper plate 110, a lower plate 130 and a plastic casing or plastic package containing the phase change material mixture 120 necessary to obtain the assembled plate 100. Figure 2 shows the assembled plate 100, where the casing 120 with the phase change material mixture therein is located in the internal cavity of the plate 100 between the upper plate 110 and the lower plate 130 and is therefore not visible. An edge portion 111 and a central portion 112 of the plate 100 are further specified.

[0042] The plastic package 120 containing the phase change material mixture is placed in an assembled plate 100 having an outer diameter of, for example, 27 cm. The plate consists of an upper plate 110 and a lower plate 130, both preferably made of porcelain, which together form a cavity in the center of the plate in which a plastic casing or plastic package containing the phase change material mixture 120 can be placed.

[0043] The plastic package containing the phase change material mixture 120 is attached to the underside of the upper plate 110 using a bonding agent, such as a silane-based adhesive, to have the best possible contact between the upper plate 110 and the package 120. In this example, 7 g of adhesive, such as Bostik Simson ISR 70-03, was applied to the center of the package 120. This was then pressed firmly against the upper plate 110 such that the adhesive spread over most of the surface of the upper side of the package 120 and minimized the amount of air trapped between the package 120 and the underside of the upper plate 110. This was then left to cure for at least 24 hours.

[0044] The lower plate 130 is then glued to the upper plate 110 and the plastic package 120 containing the phase change material mixture is glued to the underside of the upper plate 110, typically with a silicone based adhesive such as Dowsil 732. After the second glueing, a cure time is again applied, preferably at least 24 hours.

[0045] Finally, the edges between the upper and lower plates are optionally finished with a sealant such as Momentive RTV 118 to avoid water penetration and contamination in this edge zone.

[0046] In this way, an assembled plate 100 is obtained as shown in FIG.

[0047] To avoid unwanted water loss along the underside, it is optimal that there is no direct contact between the plastic package 120 containing the phase change material mixture and the lower plate 130. In this test, there was enough distance between the porcelain lower plate 130 and the package 120 to avoid this.

[0048] If the distance is too small to prevent direct contact, it is possible to apply a thin layer of insulating material, such as neoprene, to avoid direct thermal contact.

[0049] As mentioned above, the assembled plate 100 is a two-part porcelain plate. The upper plate 110 has an overall diameter of 27 cm. The central portion 112 has a diameter of 15 cm and a thickness of approximately 6 mm. The upper plate 110 has a mass of approximately 660 g and the lower plate 130 has a mass of approximately 200 g. EXAMPLES

[0050] In Example 2, the initial temperature of the three plates is compared, in particular at time 0 min, and the cooling. Using temperature sensors, this comparison is performed for both the central portion 112 and the edge portion 111, after exposure to microwave radiation at 840 W for 4 min in each case.

[0051] The first plate is a regular porcelain dinner plate, referred to as plate type 1; the second plate is the same regular porcelain dinner plate with a porcelain plate positioned as the lower plate, referred to as plate type 2; and the third plate is the above dinner plate and lower plate with a phase change material mixture packaged within the cavity, referred to as plate type 3.

[0052] The temperatures determined at successive time points for the center and edge portions are shown in the table of Figure 3. The temperature of the edge portion was measured only at time "0".

[0053] For plate type 1, after removal from the microwave oven, a temperature of 42°C is determined for the center portion, while a temperature of 78°C is measured for the edge portion.

[0054] For plate type 2, after removal from the microwave oven, a temperature of 56°C is determined for the center portion and a temperature of 70°C is measured for the edge portion.

[0055] For plate type 3, after removal from the microwave oven, a temperature of 100°C is determined and a temperature of 58°C is measured at the edge.

[0056] For plate type 1, a temperature of 32°C is determined in the centre 10 minutes after removal from the microwave, 27°C after 20 minutes, and 26°C after 30 minutes.

[0057] For plate type 2, a temperature of 45°C is determined in the centre 10 minutes after removal from the microwave, 37°C after 20 minutes, and 32°C after 30 minutes.

[0058] For plate type 3, a temperature of 73°C is determined in the center 10 minutes after removal from the microwave, 62°C after 20 minutes, 59°C after 30 minutes, 57°C after 40 minutes, and 53°C after 50 minutes. EXAMPLES

[0059] Example 3 compares the initial temperature and cooling of the same plate. Using temperature sensors, the comparison is done for both the center portion 112 and the edge portion 111 after 4 minutes in a microwave oven at 840W for the microwave plate and after 60 minutes in an oven at 120°C for the oven plate.

[0060] The plates (referred to as a microwave plate and an oven plate for microwave and oven applications, respectively) consist of the dinner plate 110 and lower plate 130 described above, with the phase change material mixture packaged within the cavity.

[0061] The temperatures determined are shown in the table in Figure 4. The edge temperatures were measured only at time "0".

[0062] For the microwave plate, after removal from the microwave oven, a temperature of 100°C is determined at the center while a temperature of 58°C is measured at the edge.

[0063] For the oven plate, after removal from the oven, a temperature of 96°C is measured at the center and 72°C at the edges.

[0064] For the microwave plate, a temperature of 73°C is measured in the center 10 minutes after removal from the microwave, 62°C after 20 minutes, 59°C after 30 minutes, 57°C after 40 minutes, and 53°C after 50 minutes.

[0065] For the oven plate, a temperature of 73°C is determined in the centre 10 minutes after removal from the oven, 61°C after 20 minutes, 58°C after 30 minutes, 56°C after 40 minutes and 52°C after 50 minutes. EXAMPLES

[0066] In Example 4, the initial temperature and cooling of a stack of four plates is determined. Using temperature sensors, this is done for both the center portion 112 and the edge portion 111 after heating for 7 minutes in a 840W microwave oven.

[0067] The plate is plate type 3 already described in Example 2.

[0068] The temperatures determined are shown in the table in Figure 5. The edge temperatures were measured only at time "0".

[0069] For the upper plate, after removal from the microwave oven, a temperature of 82°C is determined for the center portion, while a temperature of 42°C is measured for the edge portion.

[0070] For the lower plate, after removal from the microwave oven, a temperature of 93°C is measured at the center and a temperature of 43°C is measured at the edges.

[0071] For the upper plate, after removal from the microwave, the temperature in the center is measured at 73°C after 10 minutes, 58°C after 20 minutes, 56°C after 30 minutes, 53°C after 40 minutes, and 46°C after 50 minutes.

[0072] For the lower plate, a temperature of 67°C is determined in the centre 10 minutes after removal from the microwave, 64°C after 20 minutes, 61°C after 30 minutes, 56°C after 40 minutes and 49°C after 50 minutes. EXAMPLES

[0073] In Example 5, the initial temperature and cooling of a tempered glass serving dish is determined using temperature sensors, both at the center and at the edge, after 6 minutes in a 840W microwave oven.

[0074] In this example, a tempered glass serving dish assembled from an upper part 35 cm in diameter, 4 mm thick, and mass 920 g, and a component part 33 cm in diameter and mass 850 g, is used along with three plastic packages each containing 60 g of the phase change material mixture in their cavities.

[0075] The temperatures determined are shown in the table in Figure 6. The edge temperatures were measured only at time "0".

[0076] After 6 minutes of activation in the microwave, the center of the dish had temperatures of 75° C., 64° C. after 10 minutes, 62° C. after 20 minutes, 60° C. after 30 minutes, 58° C. after 40 minutes, 54° C. after 50 minutes, and 47° C. after 60 minutes. The initial temperature at the edges was 59° C. EXAMPLES

[0077] In Example 6, the initial temperature and cooling of the type 3 plates described in Example 2 is determined, in each case after successive individual exposures to microwave irradiation (840 W) for 4 minutes, as shown in the graph of FIG. 7.

[0078] The cooling of the Type 3 plates upon first use was determined to be similar to the cooling after the 10th, 20th and 30th uses, indicating the stability of the dish containing the microwave activatable phase change material mixture and the packaged microwave activatable phase change material mixture itself. EXAMPLES

[0079] In this example, the cooling of a food plate was determined, more specifically, 250 g of prepared lasagna prepared according to the preparation instructions on the packaging, which was for 30 minutes at 180° C. in a conventional oven. After preparation, portions of the 250 g of prepared lasagna were placed on a Type 2 plate and a Type 3 plate as described in Example 2.

[0080] The temperatures determined are shown in the table in Figure 8. The edge temperatures were measured only at time "0".

[0081] As shown in Table 5, in the Type 2 plate, the lasagna cools to 60° after 15.2 minutes, while in the Type 3 plate it cools after 21.6 minutes.

[0082] For the most critical temperature interval, which is the cooling of the lasagna from 60° C. to 50° C., a time of 9.5 minutes was determined for the type 2 plates, whereas for the type 3 plates this took 38.4 minutes.

[0083] The total time for cooling the lasagna in the temperature range of 70°C to 50°C was 17.0 minutes for the Type 2 plates and 52.3 minutes for the Type 3 plates.

[0084] Those skilled in the art will appreciate that the invention is not limited to the above-described embodiments and examples, and that many modifications and variations are possible within the scope of the invention, which is defined solely by the claims that follow.

Claims

1. A tableware containing a phase change material mixture, wherein the phase change material mixture includes one or more organic phase change materials selected from the group consisting of organic acids, organic alcohols, and organic esters, and one or more organic microwave susceptors selected from the group consisting of glycols, the phase change material mixture is contained in a plastic package, the phase change material mixture is disposed under the central portion of the tableware intended for placing food, and is not disposed under the edge portion of the tableware intended for handling the tableware when there is no food, the phase change material mixture is configured to be melted by microwave irradiation, tableware.

2. The tableware according to claim 1, wherein the organic phase change material has a melting point in the range of 30 to 120 °C, preferably in the range of 50 to 90 °C, more preferably in the range of 65 to 80 °C.

3. The tableware according to claim 1 or 2, wherein the organic phase change material has a boiling point higher than 150 °C, preferably higher than 200 °C, more preferably higher than 250 °C.

4. The tableware according to claim 1 or 2, wherein the organic phase change material has a flash point higher than 150 °C, preferably higher than 200 °C, more preferably higher than 250 °C.

5. The tableware according to claim 1, wherein the organic phase change material is an organic ester.

6. The tableware according to claim 5, wherein the organic phase change material is behenyl behenate.

7. The tableware according to claim 1, wherein the microwave susceptor includes monopropylene glycol and / or dipropylene glycol, and preferably, the microwave susceptor is dipropylene glycol.

8. The tableware according to claim 1, wherein the phase change material mixture substantially does not contain water.

9. The tableware according to claim 1, having a content of one or more organic microwave susceptors in the phase change material mixture of 2.5 to 25% by mass and a total amount of the phase change material mixture of 10 to 500 g.

10. The tableware according to claim 1, wherein the plastic package includes a (BO)PET film.

11. The tableware according to claim 1, wherein the tableware includes a material selected from the group consisting of porcelain, plastic, stoneware, glass, and tempered glass.

12. The tableware according to claim 1, wherein the phase change material mixture consists of one organic phase change material and one organic microwave susceptor.

13. The tableware according to claim 1, which is configured such that after heating in a microwave oven at 250 to 1250 W for 2 to 12 minutes, a molten phase change material mixture at a rate of 90 to 95% is obtained therein.

14. The tableware according to claim 1, wherein the plastic package is disposed within the hollow space of the tableware.

15. A method for manufacturing tableware containing a phase change material mixture, the method comprising: - at least partially melting and mixing one or more organic phase change materials selected from the group consisting of organic acids, organic alcohols, and organic esters, and one or more organic microwave susceptors selected from the group of glycols; - solidifying the at least partially molten phase change material mixture or pressing the at least partially solidified phase change material mixture into a specific shape; - disposing the solidified phase change material mixture within a plastic package; - disposing the phase change material mixture disposed within the plastic package under the central portion of the tableware intended for placing food, and not under the edge portion of the tableware intended for handling the tableware and where there is no food; characterized by including Preferably, - the at least partial melting and mixing of the one or more organic phase change materials and the one or more organic microwave susceptors is carried out at a temperature up to 40 °C higher than the melting point of the phase change material, and / or - the plastic package is disposed within the hollow space of the tableware.

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