US-12624268-B2 - Semi-solid biodegradable refrigerant gel

US12624268B2US 12624268 B2US12624268 B2US 12624268B2US-12624268-B2

Abstract

A semi-solid biodegradable refrigerant gel and methods of making same are disclosed. The semi-solid biodegradable refrigerant gel includes water, a biodegradable thickening agent, a crosslinking agent, an optional secondary crosslinking agent, and a chelating agent. The semi-solid biodegradable refrigerant gel does not require encasement in a high-barrier containment material.

Inventors

Benjamin Wyckoff SHORE

Assignees

Minus Works Inc.

Dates

Publication Date: 20260512
Application Date: 20230503

Claims (14)

1 . A semi-solid biodegradable refrigerant gel comprising: water; sodium carboxymethyl cellulose; aluminum sulfate; sodium aluminum sulfate; sodium benzoate; potassium sorbate; citric acid; and sodium carbonate.
2 . The semi-solid biodegradable refrigerant gel according to claim 1 , wherein the gel is encapsulated in a paper material consisting of over 85% fiber content by weight.
3 . The semi-solid biodegradable refrigerant gel according to claim 1 , wherein the semi-solid biodegradable refrigerant gel includes: about 0.86% sodium carboxymethyl cellulose by weight relative to the water; about 0.019% aluminum sulfate by weight relative to the water; about 0.064% sodium aluminum sulfate by weight relative to the water; about 0.139% sodium benzoate by weight relative to the water; about 0.034% potassium sorbate by weight relative to the water; about 0.024% citric acid by weight relative to the water; and about 0.014% sodium carbonate by weight relative to the water.
4 . The semi-solid biodegradable refrigerant gel according to claim 1 , wherein the gel does not flow or leak.
5 . The semi-solid biodegradable refrigerant gel according to claim 1 , wherein the gel retains the shape of a container where the gel solidified.
6 . The semi-solid biodegradable refrigerant gel according to claim 1 , wherein the gel has a Latent Heat of Fusion >275 J/g and a eutectic point of about 0° Celsius.
7 . The semi-solid biodegradable refrigerant gel according to claim 1 , wherein the sodium aluminum sulfate has a different dissolution rate than the aluminum sulfate and is used in concert with the aluminum sulfate to achieve a specific pot-life.
8 . The semi-solid biodegradable refrigerant gel of claim 1 , wherein the gel has a pH above 4.0.
9 . The semi-solid biodegradable refrigerant gel of claim 1 , wherein the gel is utilized in a refrigerant pack.
10 . A method of making a semi-solid biodegradable refrigerant gel comprising: providing a chamber and a disperser proximate to the chamber; depositing a predetermined amount of water into the chamber; adding a blend of raw materials to the water via the disperser, wherein the blend of raw materials comprises: sodium carboxymethyl cellulose; aluminum sulfate; sodium aluminum sulfate; sodium benzoate; potassium sorbate; citric acid; and sodium carbonate; mixing the blend of raw materials with the water to create a viscous liquid gel; filling containers or molds with the viscous liquid gel or encapsulating the viscous liquid gel in an encapsulation material; and allowing the viscous liquid gel to set in the containers or molds or encapsulation material to form the semi-solid gel.
11 . The method of claim 10 , further comprising freezing the gel to create a cold pack.
12 . The method of claim 10 , wherein the encapsulation material includes a low-barrier containment material.
13 . The method of claim 12 , wherein the low-barrier containment material is rollstock material and is converted into a pouch or bag during a filling process by sealed seams.
14 . The method of claim 11 , wherein the low-barrier containment material is a paper material consisting of over 85% fiber content by weight.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application claims the benefit of and priority to U.S. provisional application No. 63/338,056, filed on May 4, 2022, the entire contents of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The present disclosure generally relates to a novel form of refrigerant gel which does not require the use of high barrier containment material when keeping perishable or temperature sensitive items in specified temperature ranges. The refrigerant gel is a semi-solid hydrogel constructed from plant-based, biodegradable materials. This form of refrigerant gel obviates the need for high barrier containment material and thereby reduces the need for single-use plastic while enabling the use of low barrier, low environmental impact materials such as paper. Embodiments of this semi-solid biodegradable refrigerant gel may consist of over 97% water and thus may retain excellent phase change material properties associated with water. The nature of this semi-solid refrigerant gel may also prevent leakage that can be common in single-use gel packs that use a liquid refrigerant gel. The nature of this semi-solid refrigerant gel may also provide more shape stability to the cold pack which makes for a more consistent shape when frozen. The nature of this semi-solid refrigerant gel formulation allows for adjustable pot-life that enables the gel to be processed as a liquid before setting into a semi-solid. BACKGROUND Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted being prior art by inclusion in this section. The proliferation of eCommerce has resulted in a rapid rise of online generated deliveries and shipments. This trend may also be driving the increased generation of packaging materials and packaging material waste. The shipping of perishables and temperature sensitive items may require more packaging than standard products (i.e., insulation, refrigerant cold packs, box liners) and thus may generate even more waste. As grocery stores and pharmacies move more business online, as well as the rise in delivered meal-kits, prepared meals, and curated food boxes, a sharp rise in packaging waste may be further exacerbated. Packaging waste and the use of non-renewable, non-recyclable materials may be especially prevalent in the cold pack industry, a subset of the packaging material industry. Cold packs may be passive refrigerants used to keep payloads within specified temperature ranges. Most cold packs are water based because of the excellent phase change properties of water. Water has a Latent Heat of Fusion of 334 J/g as it changes phase from solid (ice) to liquid. This high Latent Heat of Fusion allows water, through changes in its phase, to absorb a significant amount of heat per unit mass and thus keep elements in its environment cool or cold. There may be several different forms of cold packs used for shipping perishables including gel packs. A gel pack may consist of a viscous gel, such as a hydrogel, contained in a pouch made with plastic film. For most shipping applications, these gel packs are considered “single-use” and as such, drive demand for single-use plastic and a significant amount of packaging waste. The typical single-use gel pack pouch is made with flexible plastic film. This flexible plastic film may be a monomaterial consisting of Low Density Polyethylene (“LDPE”) or a laminate featuring a combination of LDPE and other flexible plastic materials such as Polyester, Nylon, etc. Flexible plastic film is difficult to recycle in the United States and many other countries as evidenced by the lack of curbside recycling programs. According to the EPA's 2018 study, less than 5% of all #4 Plastic (LDPE) gets recycled, which is significantly lower than the recycle rates of other forms of plastic that are curbside recyclable like High Density Polyethylene (“HDPE”). The typical gel pack is susceptible to leaking. Even with high barrier, high strength plastic encasement, punctures and bursting are common occurrences as the gel pack is often packed in next to objects with sharp corners. Gel packs are widely used in parcel deliveries and thus they are exposed to a challenging shipment environment including jostling, drops, compression, and altitude changes, which can result in bursting and breakages. A typical broken gel pack will leak liquid refrigerant gel into its parcel and onto the payload, potentially resulting in a dissatisfied end-user and a dysfunctional or contaminated product. The typical gel pack uses a liquid refrigerant gel and thus will take on a frozen shape similar to its shape just before freezing. Gel packs are often shipped in pallet quantities to cold storage facilities where they are frozen. During transit to the cold storage facility, gel packs may shift or lump together, thereby producing a frozen gel pack that has an uneven or irregul