Heat-stable system for cold chain and manufacturing method thereof

Abstract

The present invention discloses a thermal stabilization system 100 for storing and transporting perishable goods, particularly food, in the cold chain. The system combines a biodegradable polyurethane insulated container 102 with a cooling liquid. Taking into account the hydrophilicity and soft texture of polyurethane, a commercially available moisture-proof, lightweight, food-grade coating is applied to the insulated container 102 to improve water resistance, ease handling, and extend storage time. The system 100 further includes a double-walled trough 112 for holding the goods to be stored / transported. A cooling liquid can be filled into the hollow space between the inner and outer walls of the trough. The cooling liquid is composed of water containing 30% (wt / v) polyethylene glycol (PEG)-4000. In combination with the insulated container 102, the thermal stabilization system 100 can maintain a temperature range of 2 to 15°C for 60 to 100 hours.

Description

[Technical Field]

[0001] This application claims the benefit of Indian Provisional Patent Application No. 202211059650, filed October 19, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates generally to supply chain networks, and particularly, but not exclusively, to low-temperature controlled supply chain networks or cold chains. [Background technology]

[0003] Over the past few decades, the demand for food and pharmaceuticals has increased significantly worldwide, resulting in the proliferation of storage facilities, temperature-controlled environments, and cold supply chains to provide the commodities people need for their daily lives. Despite significant technological and infrastructural advances in the cold supply chain, several aspects of the sector remain shortcomings that need to be addressed. Packaging is one such aspect. Packaging plays a critical role in the supply chain network, and selecting appropriate packaging materials and processes is crucial to ensure product freshness and safety. This invention relates to packaging for storing and transporting goods, particularly perishable food products (PFPs), in the cold chain.

[0004] Perishable food products (PFSCs), such as fruits and vegetables, account for approximately 70% of all food waste (Gardas et al., 2018). The waste of PFPs causes a significant loss of natural resources, resulting in the waste of significant amounts of resources invested in the production, transportation, and trade of these foods (Sgarbossa and Russo, 2017). Sustainability management in PFSCs is crucial due to the perishable nature of these products and their limited shelf life. Perishable food supply chains (PFSCs) are characterized by increasing concerns about food quality and safety, alarming food waste and losses, and low economic sustainability. Other factors, such as power shortages and non-availability, inadequate infrastructure, and poor connectivity, also contribute to unexpected delays in delivery and the resulting expiration of products. To mitigate these issues, heat-stabilizing systems have emerged.

[0005] Some commercially available heat-stable systems utilize insulating materials based on polystyrene, polyethylene, polyvinyl chloride, polypropylene, or polyethylene terephthalate to create heat-stable containers. However, these materials have limitations on disposal and recycling, and are unsafe for use. For example, Styrofoam is a potential carcinogen, and polyvinyl chloride contains toxic chemical additives that are harmful to humans, such as phthalates, lead, cadmium, and organotin compounds.

[0006] Several beneficial characteristics compared to the above materials make polyurethane an excellent choice for preparing heat-stable containers. Polyurethane containers are particularly cost-effective to manufacture and maintain in the food distribution sector. Their lightweight construction also makes them suitable for long-distance food transport. Furthermore, polyurethane decomposes, is harmless to the environment, and does not contain toxic chemicals that disrupt the endocrine system. Thus, polyurethane's biodegradability and non-toxicity make it an environmentally friendly alternative to other harmful options.

[0007] However, polyurethane has its own drawbacks. One of the major drawbacks of polyurethane is its hydrophilicity, which increases the risk of food spoilage. Another major drawback is that it is a very soft material, making it difficult to handle and transport. To overcome these obstacles, some manufacturers coat polyurethane with HDPE- or PET-based water-resistant polymers or other coatings. However, this treatment renders the container non-biodegradable and increases its weight, thereby increasing costs and reducing transportability. Prior art (CN206289853U and CN101435254A) discloses such processes. The present invention aims to solve this problem by coating polyurethane insulated containers with a commercially available lightweight, moisture-proof, food-grade coating layer. Thus, the coated container remains lightweight, non-toxic, and water-resistant. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] CN206289853U [Patent Document 2] CN101435254A [Patent Document 3] US4206101A [Patent Document 4] US7568359B [Patent Document 5] US20150130335A1 [Patent Document 6] US20100314397A1

[0009] Besides the insulated container, another important part of the thermostability system is the cooling pad / pouch, which helps maintain a low temperature within the insulated container. Most reported cooling pads, such as those disclosed in prior art (US4206101A and US7568359B), have a temperature range of -15°C or below, making them unsuitable for perishable goods, grains, confectionery, etc. Furthermore, the cooling agents used in cooling pads may not be safe. Prior art (US20150130335A1 and US20100314397A1) disclose aqueous polyethylene glycol and PEG(365) solutions, respectively, as cooling agents, but both contain inorganic chemicals and are therefore inherently toxic. To overcome these issues, the present invention provides the use of essentially non-toxic PEG-4000 in varying concentrations to achieve a temperature range of 2-15°C, which is ideal for perishable goods. Summary of the Invention

[0010] Some of the objectives of the present disclosure that are met by at least one embodiment herein are listed herein below.

[0011] A primary object of the present invention is to provide an improved heat stabilization system for the cold supply chain.

[0012] Another object of the present invention is to provide a lightweight, heat-stable container, thereby facilitating the handling and transportation process in the cold chain.

[0013] Another object of the present invention is to improve the shelf life of goods in the cold chain.

[0014] Another object of the present invention is to provide a wider temperature range for storage and / or transportation of goods in the cold chain.

[0015] Another object of the present invention is to provide a cost-effective and sustainable heat-stable container.

[0016] Yet another object of the present invention is to enhance customer safety by providing a food-grade, non-toxic, heat-stable container.

[0017] (overview) The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention, and is not intended to identify key / critical elements of the invention or to outline the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.

[0018] The present invention discloses a heat-stable system that combines an insulated container with a cooling liquid for the storage and / or transportation of, but not limited to, perishable foods. The present invention uses polyurethane as the insulating material that makes up the insulated container. Polyurethane is a biodegradable material and is safe for food storage. Furthermore, polyurethane has a lower thermal conductivity than heat-stable containers made from other materials. However, there are two significant drawbacks to using polyurethane. First, polyurethane is hydrophilic, increasing the risk of food spoilage. Second, polyurethane is a soft material that can be difficult to handle. To overcome these drawbacks, the present invention utilizes a commercially available moisture-proof coating to coat the polyurethane container. This coating is lightweight and food-grade. The coating process not only makes the container water-resistant and easier to handle, but also provides additional insulation, thereby extending the container's shelf life.

[0019] To keep the product cold within the container, a double-walled trough is designed with a hole in the top surface of one side through which a cooling liquid can be filled. The trough also includes a foldable handle for easy placement within the container and other handling.

[0020] The method disclosed in the present invention for preparing the cooling solution involves dissolving polyethylene glycol (PEG)-4000 in water at a concentration of 30% (weight / volume). To use this cooling solution in combination with an insulated container, the solution must be frozen at -5°C for 24 hours and then warmed to -2°C before dispensing into the trough. Alternatively, the cooling solution can be enclosed in a PET-PE pouch to form a cooling pad.

[0021] Another defining feature of the present invention is a temperature display system consisting of a temperature sensor with a one square inch display that displays the temperature of the coolant. The sensor is connected to the coolant by a wire that can be inserted into the trough through a trough hole. According to a preferred embodiment, the same hole used to fill the coolant can be used to insert the temperature sensor wire into the trough. An advantage of connecting the temperature sensor to the coolant instead of directly to the product stored in the trough is that the wire avoids direct contact with the product, which is particularly preferable when the product being stored / shipped is food, as food is highly susceptible to contamination.

[0022] The technical advantages of the present invention include the system's ability to maintain temperatures as low as -18°C, the temperature range of 2-15°C recommended for perishable foods, and the ability to achieve hold times of 60-100 hours.

[0023] In practical applications, the system ensures that stored food retains its quality characteristics, such as taste and texture. Beyond standard perishables, the system can be used to store and transport a variety of products, including rice-based products, ice cream packs, restaurant meals, designer ice cubes, etc. The invention is also suitable for areas with limited power, proving its versatility and wide range of use cases. [Brief explanation of the drawings]

[0024] The drawings described herein are for the purpose of illustrating selected embodiments only and are not intended to limit the scope of the present disclosure. The present invention will now be described in conjunction with the following illustrated figures, in which like numerals refer to like elements:

[0025] [Figure 1] 1 shows a front view of a thermal stabilization system 100. 102 - Insulated container (cold box) 104 - Insulated container lid 106 - Steel latch 108 - Sensor display [Figure 2] 2 is a rear view of the thermal stabilization system 100. 110—Hinge [Figure 3] Figure 3 shows the open heat stabilization system 100. 112 - Trough 114 - Wire 116 - Handle 118 - Trough hole

[0026] (Detailed explanation) The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.

[0027] As used herein, the term "coolant" is used to refer to an aqueous solution of Polyethylene Glycol (PEG)-4000, a phase change material (PCM). The terms "insulated vessel" or "cold box" are used interchangeably throughout this specification.

[0028] 1-4, in an exemplary embodiment, Figure 1 illustrates a proposed thermal stabilization system 100 according to the present invention. The thermal stabilization system 100 generally comprises an insulated vessel / cold box 102 and a trough 112.

[0029] The container 102 has a top lid 104 with a sensor display 108 on its top surface. The lid 104 is secured to the back of the container 102 by a hinge 110, as shown in FIG. 2, and has a latch 106 on the front for opening and closing purposes. The latch 106 is preferably made of steel and includes a spring for better locking and sturdiness. The hinge 110 is located on the outside of the container 102 for smooth opening and closing. Placing the hinge on the inside of the box makes the lid harder to open and close.

[0030] 3 and 4 show a thermostability system 100 including a trough 112 for storing goods to be maintained at low temperatures, in an embodiment proposed by the present invention. The trough 112 is a double-walled container having a hollow space between inner and outer walls and is equipped with a pair of handles 116 for easy handling. According to a preferred embodiment, the handles 116 are foldable. The trough is designed with a hole 118 (hereinafter referred to as the trough hole) on its top surface that can be used to fill the hollow space with a cooling liquid. Once the trough 112 is filled with cooling liquid and placed in the cold box 102, a wire 114 from the sensor display 108 can be connected to the cooling liquid through the trough hole 118 to monitor the temperature of the cooling liquid.

[0031] According to a preferred embodiment, the insulated container 102 is made of polyurethane, and its preparation generally involves designing the required volume of the container based on the amount of material required for storage / transport, cutting it accordingly, and then coating all surfaces of the container with one or more layers of a commercially available moisture-resistant coating to counteract the side effects of the hydrophilic nature of polyurethane. The coating process not only makes the container 102 water-resistant, but also adds an insulating layer to the container, providing additional retention time for the container. In one embodiment, the thickness of the insulating material is a minimum of 50 mm, and the thickness of the moisture-resistant coating is 4 mm.

[0032] The proposed method for preparing the coolant involves dissolving polyethylene glycol (PEG)-4000 in water to achieve a preferred concentration of 30% (weight / volume) of PEG-4000 in the aqueous solution. To be used for storing / transporting goods, the coolant must first be frozen at -5°C for 24 hours and then warmed to -2°C before being filled into the trough 112. The solution is poured into the trough 112 through the trough hole 118 until the space between the inner and outer walls of the double-walled trough is filled.

[0033] In another preferred exemplary embodiment, the cooling liquid is filled into cooling pads for other uses, such as for cold storage of goods. The cooling pads were prepared by heat-sealing one liter of cooling liquid, prepared by dissolving 30 grams of PEG-4000 in one liter of distilled water, into polyethylene terephthalate-polyethylene (PET-PE) pouches. (The amount of solution required depends on the weight of the food product to be shipped, and the weight-to-volume ratio should be 1:1.) Before being placed in the insulated container 102, the cooling pads were frozen at -5°C for 24 hours and then returned to -2°C.

[0034] The dimensions of the insulated container 102 and the concentration of PEG-4000 can be customized depending on the weight, volume and temperature requirements of the goods being stored / transported.

[0035] The technical advantages of the present invention are demonstrated in the form of experimental results presented below.

[0036] The present invention preferably uses polyurethane foam (PUF) as the insulating material in the thermal stabilization system 100 .

[0037] Monitoring the coolant temperature, displayed on the sensor display 108, has been shown to reduce the risk of food contamination compared to sensors that monitor food temperature. This is because measuring food temperature requires contact between the sensor and the food, which not only presents challenges in sensor placement on the food but can also lead to an unsanitary process. The component placement of the present invention overcomes this drawback.

[0038] Furthermore, the sensor display is just one square inch in size and constantly displays the temperature during transshipment or storage. The display is battery-powered and can be replaced after a few months for maintenance. Because the battery is replaceable, no charging circuit is required.

[0039] Designed for superior performance under cryogenic conditions, the thermostabilization system 100 of the present invention ensures that food remains consistently frozen at temperatures as low as -18°C and has the ability to maintain these frozen temperatures for extended periods of time. By using a combination of coated polyurethane containers and PEG-4000 cooling fluid, a temperature range of 2-15°C and a hold time of 60-100 hours were achieved. Various container thicknesses and PEG-4000 solution concentrations were tested to achieve different temperature ranges and hold times.

[0040] It has been observed that when the thermostabilizing system 100 described in the present invention is used on food products, the food products maintain their quality without loss of aroma, taste, or texture. Storage of food products at extremely low temperatures, i.e., below 0°C and above 8°C, is not desirable because it leads to loss of taste and texture and frequent spoilage of food products due to freeze-thaw cycles has been observed.

[0041] It has been determined that the manufacturing costs of the containers used in the present invention are lower than other commercially available containers.

[0042] The present invention discloses a thermal stabilization system 100 that combines an insulated container 102 with a cooling liquid (PEG-4000 solution) and is primarily intended for storing and / or transporting perishable foods, but is not limited thereto. The present invention uses polyurethane as the insulating material that makes up the insulated container. Polyurethane is a biodegradable material and safe for food storage. Furthermore, polyurethane has lower thermal conductivity than thermal containers made from other materials. However, using polyurethane has two significant drawbacks. First, polyurethane is hydrophilic, increasing the risk of food spoilage. Second, polyurethane is a soft material that is difficult to handle. To overcome these drawbacks, the present invention utilizes a commercially available moisture-proof coating to coat the polyurethane container. This coating is lightweight and food-grade. The coating process not only makes the container water-resistant and easier to handle, but also provides additional insulation, thereby extending the container's shelf life.

[0043] The most efficient form of the present invention was observed to be the use of polyurethane with a moisture barrier coating for all insulating parts of the container, compared to other containers available on the market that use polystyrene, polyethylene, polyvinyl chloride, polypropylene, and polyethylene terephthalate.

[0044] The container's insulation was found to be lightweight and biodegradable, making it convenient for storage, transportation, and disposal after use.

[0045] The preferred dimensions of the heat stabilization system 100 are as follows: The dimensions (length x width x height (cm)) required for a storage volume of 8 L in the trough are as follows: External dimensions of the insulated container 102 (length x width x height (cm)): 54.2 x 42.7 x 40 Insulated container 102 internal dimensions (L x W x H (cm)) with removable trough removed: 43 x 31.5 x 29 Trough 112 internal dimensions (length x width x height (cm)): 35.4 x 23.9 x 22.4

[0046] The best results were observed when the preferred concentration of PEG-4000 in water solution was kept at 30% (wt / vol) for storage in the desired temperature range.

[0047] In addition to storing / transporting fresh produce (meat, poultry, fish, milk, eggs, many fruits and fresh vegetables, prepared foods, etc.), the present invention has several use cases, such as: Storage and transportation of rice based ingredients, ice cream packs, confectionery, milk & dairy products, water pouches etc. Storage and delivery of hot / cold meals to restaurants, railway canteens, cafeterias etc. Storage and delivery of designer ice cubes for restaurants, bars, pubs, nightclubs, etc. Storage utilities for street vendors, hawkers, etc. Storage solutions for areas with little or no electricity, such as neighborhoods or beaches.

[0048] While the foregoing detailed description has presented at least one exemplary embodiment, it should be understood that numerous variations exist, and that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as defined in the appended claims and their legal equivalents.

Claims

1. an insulated container (102) for storing and transporting goods at low temperatures, said container (102) being made of polyurethane and coated with at least one moisture-proof coating; a double-walled trough (112) having at least one trough hole (118) on the top surface of one of its sides for holding goods to be stored / transported, said trough (112) being designed to be placed inside said insulated container (102); a cooling liquid prepared by dissolving polyethylene glycol (PEG)-4000 in water, which provides the low temperature range necessary for storing and transporting the product; A cold chain heat stabilization system (100) comprising:

2. The thermal stabilization system of claim 1 , wherein the coolant is filled into the trough (112) through the trough hole (118).

3. 2. The thermal stabilization system of claim 1, wherein the trough (112) is designed with foldable handles (116) at the top of two opposing sides of the trough.

4. 10. The thermal stability system of claim 1, wherein the concentration of said PEG-4000 in said cooling fluid is 30 grams per liter of water.

5. 2. The thermal stabilization system of claim 1, wherein the insulated container (102) has a top lid (104) secured by a plurality of hinges (110), and the lid (104) can be opened and closed using one or more latches (106) provided on the front side of the lid (104) and the insulated container (102).

6. 6. The thermal stabilization system of claim 5, wherein the lid (104) comprises a sensor display screen (108) that displays the current temperature of the coolant by connecting with the coolant via a wire (114), the wire (114) being inserted into the trough (112) via a trough hole (118).

7. The thermally stable system of claim 1, wherein the insulated container (102) has a wall thickness of 50 mm.

8. 10. The heat-stable system of claim 1, wherein the moisture-resistant coating is a commercially available lightweight, food-grade coating.

9. 10. The thermostable system of claim 1, wherein a temperature range of 2°C to 15°C is maintained within the insulated container (102) for 60 to 100 hours.

10. Making insulated containers with polyurethane, coating all surfaces of the insulated container with at least one moisture-proof coating to make the container water-resistant and sturdy; preparing a cooling solution by dissolving polyethylene glycol (PEG)-4000 in water at a concentration of 30% (weight / volume); freezing the cooling liquid at -5°C for 24 hours, then warming it to -2°C, and then filling it between the outer and inner walls of the double-walled trough; placing the trough filled with the cooling liquid into the insulated container; Here, a method for adjusting a cold chain heat stabilization system (100) capable of maintaining a temperature range of 2°C to 15°C for 60 to 100 hours in an insulated container.

Images