KR102753206B1 - Eco-friendly refrigerant for ice pack, ice pack comprising the same, and method of manufacturing the ice pack - Google Patents

Abstract

The present invention relates to an environmentally friendly refrigerant for an ice pack, an ice pack comprising the same, and a method for manufacturing the ice pack. More specifically, by mixing two or more kinds of eutectics having high melting points at an appropriate ratio to form a phase change material having a eutectic point in a temperature range of 2 to 8°C and then mixing the same with water, an environmentally friendly refrigerant for an ice pack can be manufactured, thereby significantly improving cold preservation and the duration of cold temperature. In addition, by using a eutectic such as an organic acid or alcohol, the ice pack has the advantages of being environmentally friendly and being reusable.

Description

Eco-friendly refrigerant for ice pack, ice pack comprising the same, and method of manufacturing the ice pack

The present invention relates to an environmentally friendly refrigerant for an ice pack, an ice pack containing the same, and a method for manufacturing the ice pack.

PCM(Phase Change Material) is a phase change material that absorbs external heat through a phase change process (physical change) and releases it at a specific temperature to maintain the target temperature. In other words, a phase change material is a material that has a heat regulating function that can absorb and release latent heat while changing its phase form without a temperature change at a specific temperature, and is an innovative temperature regulating material that stores the surrounding heat and releases it when needed.

Latent heat has an energy storage and release capacity tens to hundreds of times greater than that of sensible heat at the phase change temperature, so it can maximize energy efficiency compared to existing energy materials that utilize sensible heat. It is structured into various forms such as thin films, fibers, and particles and is utilized in industries such as energy industries, housing systems, functional clothing, and heat protection systems for digital devices.

However, existing PCMs have problems that make them difficult to apply in real life due to phase separation, leakage, low heat resistance, and low processability. Most phase change materials have problems such as liquid leakage due to their low molecular structure when changing from solid to liquid, uneven melting due to low heat resistance, and recrystallization.

Therefore, research and development of new phase change materials that can improve liquid leakage, low heat resistance, and processability are necessary.

Korean Patent Publication No. 2016-0017263

In order to solve the above problems, the purpose of the present invention is to provide an eco-friendly refrigerant for an ice pack using a phase change material including two or more types of eutectic mixtures.

In addition, the present invention aims to provide an ice pack including the eco-friendly refrigerant for the ice pack.

In addition, the present invention aims to provide a method for manufacturing the ice pack.

The present invention provides an eco-friendly refrigerant for an ice pack, comprising: a phase change material including a eutectic mixture of two or more selected from the group consisting of lauric acid, pentadecane, formic acid, arachidic acid, 1-octadecanol, 1-hexadecane, 1-dodecanol, caprylic acid, pentadecane, 1-tetradecanol, methyl stearate, 1,4-butanediol, polyethylene glycol polymers, polypropylene glycol polymers, and polyethylene imine polymers; and water.

In addition, the present invention provides an ice pack comprising an eco-friendly refrigerant for an ice pack according to the present invention.

In addition, the present invention provides a method for manufacturing an ice pack, including a step of manufacturing a phase change material including a eutectic mixture of two or more selected from the group consisting of lauric acid, pentadecane, formic acid, arachidic acid, 1-octadecanol, 1-hexadecane, 1-dodecanol, caprylic acid, pentadecane, 1-tetradecanol, methyl stearate, 1,4-butanediol, polyethylene glycol-based polymers, polypropylene glycol-based polymers, and polyethyleneimine-based polymers; a step of manufacturing an eco-friendly refrigerant for an ice pack including the phase change material; and a step of introducing the eco-friendly refrigerant for an ice pack into a packaging material and sealing it.

The eco-friendly refrigerant for an ice pack according to the present invention is prepared by mixing two or more kinds of eutectics having high melting points at an appropriate ratio to form a phase change material having a eutectic point in a temperature range of 2 to 8°C, and manufacturing an eco-friendly refrigerant for an ice pack including the same, thereby significantly improving cold preservation and the duration of cold temperature, and by using eutectics such as organic acids and alcohols, it has the advantages of being eco-friendly and having excellent reusability.

The effects of the present invention are not limited to the effects mentioned above. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

Figure 2 is a graph showing the temperature change over time for ice packs manufactured using eco-friendly refrigerants for ice packs of Examples 1 to 3 and Comparative Example 1 according to the present invention.
Figure 3 is a graph showing the results of measurements using differential scanning calorimetry (DSC) on ice packs manufactured using eco-friendly refrigerants for ice packs of Examples 1 to 3 and Comparative Example 1 according to the present invention.
Figure 4 is a graph showing the results of measurement using differential scanning calorimetry (DSC) on ice packs manufactured using eco-friendly refrigerants for ice packs of Example 2 and Comparative Examples 2 and 3 according to the present invention.
FIG. 5 is a graph showing heat flow (mW) according to temperature after repeating freezing and thawing for 100 cycles for an ice pack manufactured using an eco-friendly refrigerant for an ice pack of Example 2 according to the present invention.

Hereinafter, the present invention will be described in more detail with one embodiment.

The present invention relates to an environmentally friendly refrigerant for an ice pack, an ice pack containing the same, and a method for manufacturing the ice pack.

As explained above, existing phase change materials may cause liquid leakage due to their low molecular structure when changing from a solid to a liquid phase, may cause uneven melting due to low heat resistance, and may cause problems such as recrystallization.

Accordingly, in order to improve such problems, the present invention mixes two or more kinds of eutectics having high melting points at an appropriate ratio to form a phase change material having a eutectic point in a temperature range of 2 to 8 ℃, and manufactures an eco-friendly refrigerant for an ice pack containing the same, thereby significantly improving cold preservation and the duration of cold temperature, and has the advantages of being eco-friendly and having excellent reusability by using eutectics such as organic acids and alcohols.

Specifically, the present invention provides an eco-friendly refrigerant for an ice pack, comprising: a phase change material including a eutectic mixture of two or more selected from the group consisting of lauric acid, pentadecane, formic acid, arachidic acid, 1-octadecanol, 1-hexadecane, 1-dodecanol, caprylic acid, pentadecane, 1-tetradecanol, methyl stearate, 1,4-butanediol, polyethylene glycol polymers, polypropylene glycol polymers, and polyethylene imine polymers; and water.

According to the freezing point depression (freezing point depression) theory, when a solute is added to a pure solvent to make a solution, the freezing point of the solution becomes lower than the freezing point of the solvent. Accordingly, in order to form a phase change material suitable for 2 to 8°C, it is important to mix a eutectic substance exceeding 8°C. In this respect, the eutectic temperature and eutectic latent heat for two or more eutectic mixtures can be predicted by the following mathematical equations 1 and 2.

[Mathematical Formula 1]

[Mathematical formula 2]

(In the above mathematical expression 1 or 2, T _m is the melting point (K) of the eutectic, H m is the latent heat (J/mol) of the eutectic, X _i is the molar ratio of the i component, Ti is the melting point (K) of the i component, H _i is the latent heat (J/mol) of the i component, C _pLi is the specific heat of the i component in the solid state at a constant pressure (J/K mol), C _pSi is the specific heat of the i component in the liquid state at a constant pressure (J/mol K), and R represents the gas constant (8.314 J/K mol).)

Preferably, the phase change material may be at least one selected from the group consisting of a eutectic mixture of lauric acid and pentadecane; a eutectic mixture of formic acid and pentadecane; a eutectic mixture of 1-octadecanol and formic acid; a eutectic mixture of 1-hexadecane and formic acid; a eutectic mixture of 1-dodecanol and caprylic acid; a eutectic mixture of caprylic acid and pentadecane; a eutectic mixture of 1-tetradecanol and pentadecane; a eutectic mixture of 1-hexadecanol and pentadecane; a eutectic mixture of methyl stearate and pentadecane; and a eutectic mixture of 1,4-butanediol and a polyethylene glycol-based polymer.

More preferably, the phase change material may be at least one selected from the group consisting of a eutectic mixture of 1-dodecanol and caprylic acid; a eutectic mixture of caprylic acid and pentadecane; a eutectic mixture of 1-tetradecanol and pentadecane; a eutectic mixture of 1-hexadecanol and pentadecane; and a eutectic mixture of 1,4-butanediol and a polyethylene glycol polymer.

Most preferably, the phase change material may be a eutectic mixture of 1,4-butanediol and a polyethylene glycol polymer. The 1,4-butanediol is a colorless, viscous, stable substance that can serve to increase viscosity. In addition, since it has excellent miscibility with the polyethylene glycol polymer, it can be easily mixed, and various temperature ranges can be designed depending on the molecular weight and composition ratio of the polyethylene glycol polymer.

In addition, the polyethylene glycol polymer is an environmentally friendly biodegradable polymer, and has a phase change temperature of 8 to 70° C. depending on the molecular weight, so it has the characteristic of being able to design various temperature ranges. In addition, the polyethylene glycol polymer has an advantage of being able to minimize and simplify the manufacturing process due to its excellent miscibility since it dissolves well in alcohol or water. It is preferable to use the polyethylene glycol polymer having a weight average molecular weight of 400 to 1000 g/mol, preferably 460 to 950 g/mol, more preferably 500 to 900 g/mol, and most preferably 550 to 800 g/mol. If the weight average molecular weight is less than 400 g/mol, the stability of the phase change material may be lowered due to the low molecular weight, and on the contrary, if it exceeds 1000 g/mol, the eutectic point is significantly increased due to the high molecular weight, so that the refrigerant preservation and maintenance effect in the temperature range of 2 to 8° C. cannot be expected.

The eutectic mixture of the above 1,4-butanediol and polyethylene glycol polymer has the best miscibility between the two components compared to other eutectic mixtures, excellent physical property stability, and the advantage of maintaining the temperature for a long time by slowly increasing the temperature in the temperature range of 2 to 8 ℃.

At this time, the eutectic mixture may be a mixture of 1,4-butanediol and a polyethylene glycol-based polymer in a weight ratio of 25:75 to 40:60, preferably 28:72 to 37:63. In particular, if the content of the polyethylene glycol-based polymer is less than 60 weight ratio, the latent heat may decrease, which may reduce the long-term low-temperature duration, and a phase separation phenomenon may occur in the range of -10 to 10 ℃, making reuse impossible. On the other hand, if the weight ratio exceeds 75, the viscosity may increase, causing the refrigerant to clump, which may make it difficult to evenly and stably absorb and release heat.

The phase change material may have a viscosity of 0.065 to 28 Pa·s at 20°C and a phase transition temperature of 2 to 8°C. Preferably, the viscosity is 0.08 to 20 Pa·s and the phase transition temperature is 2.8 to 7.8°C, more preferably, the viscosity is 0.1 to 16 Pa·s and the phase transition temperature is 3.7 to 6.9°C, and most preferably, the viscosity is 0.15 to 12 Pa·s and the phase transition temperature is 4.7 to 5.6°C.

At this time, if the eco-friendly refrigerant for the ice pack does not satisfy both the viscosity and melting point of the above range, it is difficult to maintain the cooling property for a long time, the refrigerant made with low viscosity is difficult to maintain the shape, and the refrigerant made with high viscosity is difficult to inject into the packaging bag.

The above eco-friendly refrigerant for the ice pack can reach a temperature of 10°C in 4 hours or more when exposed to room temperature.

The above eco-friendly refrigerant for the ice pack may further include an additive. The additive may be mixed to provide density enhancement and property stabilization, and to improve the temperature retention time of 2 to 8° C. Specific examples of the additive may include at least one selected from the group consisting of graphite, stearyl alcohol, carbon nanotubes, and silica gel.

In particular, although not explicitly described in the examples or comparative examples below, an eco-friendly refrigerant for an ice pack according to the present invention was manufactured under the following four different conditions. The manufactured eco-friendly refrigerant for an ice pack was put into a packaging material together with water and sealed to manufacture an ice pack. After performing freezing and thawing once on the manufactured ice pack, the density, sharpness, and supercooling degree of the refrigerant in the ice pack were evaluated by a conventional method.

As a result, unlike other conditions and other numerical ranges, when all of the conditions below were satisfied, the density of the refrigerant in the ice pack increased from 1.017 to 1.270 g/ml at 25°C by adding polyethylene glycol to 1,4-butanediol, the sharpness of the refrigerant decreased, and the time for efficiently maintaining the appropriate temperature was prolonged because the supercooling phenomenon did not occur.

① The phase change material is a eutectic mixture of 1,4-butanediol and a polyethylene glycol-based polymer, ② The eutectic mixture is a mixture of 1,4-butanediol and a polyethylene glycol-based polymer in a weight ratio of 25:75 to 40:60, ③ The polyethylene glycol-based polymer has a weight average molecular weight of 500 to 900 g/mol, and ④ The phase change material may have a viscosity of 0.1 to 16 Pa·s at 20°C and a phase transition temperature of 3.7 to 6.9°C.

However, if any one of the above four conditions is not met, the refrigerant is excessively supercooled, resulting in excessive energy consumption during cooling, and the ice is formed in an excessively sharp shape, resulting in a reduced contact point with the target, resulting in a low cooling effect. In addition, it was found that the density of the refrigerant within the ice pack decreases, resulting in an increase in thermal conductivity.

In particular, although not explicitly described in the examples or comparative examples below, in the eco-friendly refrigerant for ice packs according to the present invention, the refrigerant for ice packs manufactured under the following five different conditions was put into a packaging material together with water and sealed to manufacture an ice pack. The manufactured ice packs were each put into fruits, vegetables and meat products, sealed, and stored in an environment of 25°C and 80% relative humidity for 48 hours, and the appearance of the fruits, vegetables and meat, the cold retention time and the product preservation status and thermal stability over time were evaluated by a conventional method.

As a result, unlike other conditions and other numerical ranges, when all of the conditions below were satisfied, fruits, vegetables, and meat products did not spoil, and their appearances were good. It was found that the temperature of the ice pack rose slowly in a closed space, so that the cold retention time lasted a long time, and it was confirmed that the freshness of the products was maintained as a result. In addition, some of the refrigerant inside the ice pack did not leak to the outside, and the thermal stability of the refrigerant was maintained even when the temperature rose, so that the cooling capacity was excellent.

① The phase change material is a eutectic mixture of 1,4-butanediol and a polyethylene glycol-based polymer, ② The eutectic mixture is a mixture of 1,4-butanediol and a polyethylene glycol-based polymer in a weight ratio of 25:75 to 40:60, ③ The polyethylene glycol-based polymer has a weight average molecular weight of 550 to 800 g/mol, ④ The phase change material has a viscosity of 0.15 to 12 Pa·s at 20°C and a phase transition temperature of 4.7 to 5.6°C, and ⑤ The eco-friendly refrigerant for ice packs can reach a temperature of 10°C in 4 hours or more when exposed to room temperature.

However, if any one of the above five conditions is not met, the temperature of the refrigerant inside the ice pack rises rapidly, shortening the time it takes to maintain the cold, causing fruits and vegetables to wilt or become mushy, and some meat products to rot and emit an unpleasant odor. In addition, some of the refrigerant leaks outside the ice pack, rapidly reducing the cooling effect, and the thermal stability of the refrigerant is poor, causing each phase to separate and evaporate, reducing reusability.

Meanwhile, the present invention provides an ice pack comprising an eco-friendly refrigerant for an ice pack according to the present invention.

In addition, the present invention provides a method for manufacturing an ice pack, including a step of manufacturing a phase change material including a eutectic mixture of two or more selected from the group consisting of lauric acid, pentadecane, formic acid, arachidic acid, 1-octadecanol, 1-hexadecane, 1-dodecanol, caprylic acid, pentadecane, 1-tetradecanol, methyl stearate, 1,4-butanediol, polyethylene glycol-based polymers, polypropylene glycol-based polymers, and polyethyleneimine-based polymers; a step of manufacturing an eco-friendly refrigerant for an ice pack including the phase change material; and a step of introducing the eco-friendly refrigerant for an ice pack into a packaging material and sealing it.

In the step of manufacturing the above phase change material, the eutectic mixture can predict the eutectic temperature and eutectic latent heat for two or more eutectic mixtures by the following mathematical equations 1 and 2.

[Mathematical Formula 1]

[Mathematical formula 2]

(In the above mathematical expression 1 or 2, T _m is the melting point (K) of the eutectic, H m is the latent heat (J/mol) of the eutectic, X _i is the molar ratio of the i component, Ti is the melting point (K) of the i component, H _i is the latent heat (J/mol) of the i component, C _pLi is the specific heat of the i component in the solid state at a constant pressure (J/K mol), C _pSi is the specific heat of the i component in the liquid state at a constant pressure (J/mol K), and R represents the gas constant (8.314 J/K mol).)

The step of preparing the above phase change material may be performed by mixing the eutectic mixture at 33 to 47° C. for 1 to 20 minutes, preferably at 36 to 44° C. for 6 to 15 minutes, and most preferably at 38 to 42° C. for 8 to 12 minutes to prepare the phase change material. In particular, when the mixing temperature is less than 36° C. or the mixing time is less than 8 minutes, the miscibility of the phase change material is not good, so that the eutectic point is unstable. On the other hand, when the mixing temperature is more than 44° C. or the mixing time is more than 15 minutes, the miscibility of the phase change material is improved, but the stability is reduced, so that the temperature is not maintained at a specific temperature over time but continuously increases. However, when ultrasonic treatment is performed to increase the miscibility during the mixing, the stability of the phase change material may be reduced.

The above packaging material is not particularly limited, and may be made of one or more materials selected from the group consisting of low-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, polyethylene terephthalate, and nylon.

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples.

Manufacturing Examples 1 to 10: Manufacturing of Phase Change Materials

The first eutectic and the second eutectic were applied to the above mathematical equations 1 and 2, and the eutectic mixture was mixed at a ratio shown in Table 1 below at 40° C. for 30 minutes to produce a phase change material. At this time, polyethylene glycol having a weight average molecular weight of 400 to 1000 g/mol was used.

Experimental Example 1: Measurement of phase change temperature of phase change material

The phase change temperature of each phase change material manufactured in the above manufacturing examples 1 to 12 was measured by a conventional method, and the results are shown in Table 2.

According to the results in Table 2 above, it was found that all of the Manufacturing Examples 1 to 12 had a phase change temperature of 2 to 8 ℃, which was an appropriate temperature range. Considering the mixing characteristics, latent heat, and appropriate temperature range of the two components, Manufacturing Examples 4 to 7 and 9 to 12 were preferable, more preferably Manufacturing Examples 4, 6, 7, 10, and 11, and most preferably Manufacturing Examples 4, 10, and 11. It was confirmed that these compositions have excellent mixing properties of the two materials due to structural characteristics, which can simplify the process for manufacturing a refrigerant.

Examples 1 to 3 and Comparative Example 1: Preparation of eco-friendly refrigerant for ice pack

For the phase change material of the above Manufacturing Example 11, polyethylene glycol and 1,4-butanediol were added at a mixing ratio shown in Table 3 below according to the theoretical eutectic point calculation results to prepare a eutectic mixture. Then, the eutectic mixture was mixed at 40°C for 30 minutes to prepare an eco-friendly refrigerant for an ice pack.

Comparative Example 2

An eco-friendly refrigerant for an ice pack was manufactured using the same method as in Example 2, except that the eutectic mixture was sonicated for 5 minutes to manufacture a phase change material.

Comparative Example 3

An eco-friendly refrigerant for an ice pack was manufactured using the same method as in Example 2, except that the eutectic mixture was sonicated for 10 minutes to manufacture a phase change material.

Experimental Example 2-1: Evaluation of ice pack cooling performance according to the mixing ratio of eutectic mixture, which is a phase change material

The eco-friendly refrigerants for ice packs manufactured in Examples 1 to 3 and Comparative Example 1 were put into packaging materials and sealed to manufacture ice packs. Then, for each ice pack, the temperature retention time of the ice pack was evaluated for 300 minutes using a data logger. The measurement results are shown in Table 4 and Fig. 2 below.

Figure 2 is a graph showing the temperature change over time for ice packs manufactured using the eco-friendly refrigerant for ice packs of Examples 1 to 3 and Comparative Example 1.

According to the results of the above FIG. 2 and Table 4, in the case of the above Examples 1 to 3, the temperature of the ice pack gradually increased over time compared to the above Comparative Example 1, and in particular, it was found that the ice pack maintained a temperature range of 2 to 8℃ for a long time between about 50 minutes and 220 minutes. In particular, it was confirmed that the above Example 2 was the most stable and had the longest temperature retention time. On the other hand, in the case of the above Comparative Example 1, the temperature was briefly maintained without significant change between the initial 10 minutes and 80 minutes, and then increased significantly after 100 minutes.

Experimental Example 2-2: Evaluation of Ice Pack Cooling Performance According to Mixing Ratio of Eutectic Mixture, a Phase Change Material

For the ice pack manufactured through the above Experimental Example 2-1, the temperature duration was measured at a heating rate of 3 min/℃ in a temperature range of -30 to 30 ℃ using a differential scanning calorimeter (DSC). The measurement results are shown in Fig. 3.

FIG. 3 is a graph showing the results of measuring ice packs manufactured using the eco-friendly refrigerant for ice packs of Examples 1 to 3 and Comparative Example 1 using differential scanning calorimetry (DSC). Referring to FIG. 3, it was confirmed that the thermal behaviors measured through DSC analysis of Examples 1 to 3 all showed the same aspects. In particular, it was found that a phase transition phenomenon occurred in the temperature range of 0 to 10°C, and a heat absorption phenomenon occurred in the temperature range of 10°C or higher, indicating that the ice packs had a refrigerant effect at room temperature.

Experimental Example 3: Evaluation of Ice Pack Cooling Performance According to Mixing Method of Eutectic Mixture, a Phase Change Material

An ice pack was manufactured using the eco-friendly refrigerant for ice packs of Example 2 and Comparative Examples 1 and 2 in the same manner as in Experimental Example 2-1, and then the temperature change of the ice pack was measured to evaluate the temperature duration. The measurement results are shown in Fig. 4.

Figure 4 is a graph showing the results of measuring the temperature duration using a data logger for ice packs manufactured using the eco-friendly refrigerant for ice packs of Example 2 and Comparative Examples 2 and 3. Referring to Figure 4, in the case of Example 2, it was confirmed that the temperature of the ice pack was maintained in the range of 2 to 8°C for 50 to 250 minutes and slowly increased with a slight difference.

On the other hand, in the case of Comparative Examples 2 and 3, it was confirmed that although the miscibility of the phase change material was improved due to ultrasonic treatment, the stability of the phase change material was relatively reduced, and the temperature was not maintained at a specific temperature but increased over time.

Experimental Example 4: Evaluation of the reusability of ice packs

An ice pack was manufactured using the eco-friendly refrigerant for the ice pack of Example 2 in the same manner as in Experimental Example 2-1. The manufactured ice pack was subjected to 100 cycles of freezing and thawing to evaluate the heat flow (mW) in the temperature range of -15 to 25°C. The results are shown in Fig. 5.

Figure 5 is a graph showing the heat flow (mW) according to temperature for an ice pack manufactured using the eco-friendly refrigerant for the ice pack of Example 2 after repeating freezing and thawing for 100 cycles. Referring to Figure 5, it was found that the heat flow (mW) in the temperature range of -15 to 25°C for 1, 80, and 100 cycles was all the same, indicating excellent reusability.

Claims (14)

A phase change material comprising a eutectic mixture of 1,4-butanediol and a polyethylene glycol polymer; and water;
The above eutectic mixture of 1,4-butanediol and polyethylene glycol-based polymer is an eco-friendly refrigerant for ice packs, wherein 1,4-butanediol and polyethylene glycol-based polymer are mixed in a weight ratio of 28:72 to 37:63.
In the first paragraph,
The above eutectic mixture is an eco-friendly refrigerant for an ice pack, wherein the eutectic temperature and eutectic latent heat for two or more eutectic mixtures are predicted by the following mathematical equations 1 and 2.
[Mathematical formula 1]

[Mathematical formula 2]

(In the above mathematical expression 1 or 2, T _m is the melting point (K) of the eutectic, H m is the latent heat (J/mol) of the eutectic, X _i is the molar ratio of the i component, Ti is the melting point (K) of the i component, H _i is the latent heat (J/mol) of the i component, C _pLi is the specific heat of the i component in the solid state at a constant pressure (J/K mol), C _pSi is the specific heat of the i component in the liquid state at a constant pressure (J/mol K), and R represents the gas constant (8.314 J/K mol).)
delete delete In the first paragraph,
The above polyethylene glycol polymer is an eco-friendly refrigerant for ice packs having a weight average molecular weight of 400 to 1000 g/mol.
In the first paragraph,
The above phase change material is an eco-friendly refrigerant for an ice pack having a viscosity of 0.065 to 28 Pa·s at 20°C and a phase transition temperature of 2 to 8°C.
In the first paragraph,
The above eco-friendly refrigerant for ice packs is an eco-friendly refrigerant for ice packs that reaches a temperature of 10°C in 4 hours or longer when exposed to room temperature.
In the first paragraph,
The eco-friendly refrigerant for the ice pack further comprises at least one additive selected from the group consisting of graphite, stearyl alcohol, carbon nanotubes, and silica gel.
In the first paragraph,
The above phase change material is a eutectic mixture of 1,4-butanediol and polyethylene glycol polymers.
The above eutectic mixture is a mixture of 1,4-butanediol and polyethylene glycol polymers in a weight ratio of 25:75 to 40:60.
The above polyethylene glycol polymer has a weight average molecular weight of 500 to 900 g/mol,
The above phase change material is an eco-friendly refrigerant for an ice pack having a viscosity of 0.1 to 16 Pa·s at 20°C and a phase transition temperature of 3.7 to 6.9°C.
In Article 9,
The above phase change material is a eutectic mixture of 1,4-butanediol and polyethylene glycol polymers.
The above eutectic mixture is a mixture of 1,4-butanediol and polyethylene glycol polymers in a weight ratio of 25:75 to 40:60.
The above polyethylene glycol polymer has a weight average molecular weight of 550 to 800 g/mol,
The above phase change material has a viscosity of 0.15 to 12 Pa·s at 20°C and a phase transition temperature of 4.7 to 5.6°C.
The above eco-friendly refrigerant for ice packs is an eco-friendly refrigerant for ice packs that reaches a temperature of 10°C in 4 hours or longer when exposed to room temperature.
An ice pack comprising an eco-friendly refrigerant for an ice pack selected from any one of claims 1, 2, and 5 to 10.
A step for producing a phase change material comprising a eutectic mixture of 1,4-butanediol and a polyethylene glycol-based polymer;
A step for producing an eco-friendly refrigerant for an ice pack containing the above phase change material; and
Including a step of putting the eco-friendly refrigerant for the ice pack into the packaging material and sealing it;
A method for manufacturing an ice pack, wherein the eutectic mixture of the above 1,4-butanediol and polyethylene glycol polymer is a mixture of 1,4-butanediol and polyethylene glycol polymer in a weight ratio of 28:72 to 37:63.
In Article 12,
A method for manufacturing an ice pack, wherein in the step of manufacturing the above phase change material, the eutectic mixture predicts the eutectic temperature and eutectic latent heat for two or more eutectic mixtures by the following mathematical equations 1 and 2.
[Mathematical formula 1]

[Mathematical formula 2]

(In the above mathematical expression 1 or 2, T _m is the melting point (K) of the eutectic, H m is the latent heat (J/mol) of the eutectic, X _i is the molar ratio of the i component, Ti is the melting point (K) of the i component, H _i is the latent heat (J/mol) of the i component, C _pLi is the specific heat of the i component in the solid state at a constant pressure (J/K mol), C _pSi is the specific heat of the i component in the liquid state at a constant pressure (J/mol K), and R represents the gas constant (8.314 J/K mol).)
In Article 12,
A method for manufacturing an ice pack, wherein the step of manufacturing the phase change material comprises mixing the eutectic mixture at 33 to 47° C. for 1 to 20 minutes to manufacture the phase change material.