GB1596076A

GB1596076A - Freezing mixture compositions

Info

Publication number: GB1596076A
Application number: GB1995478A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-05-18
Filing date: 1978-05-16
Publication date: 1981-08-19
Also published as: DE2821703A1; JPS5413050A; DE2821703C3; DE2821703B2

Description

(54) FREEZING MIXTURE COMPOSITIONS (71) I, TOMOJI TANAKA a Japanese citizen of 19-8 Hozancho, Toyonaka-shi, Osaku-fu, Japan, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to freezing mixtures, and more particularly, to freezing mixture compositions which retain a freezing function for a long time on use are prevented from deliquescence upon storage and transportation.

Freezing mixtures have been used for the purpose of cooling or freezing ice cream, fish, beverages, foods, medical supplies, etc., or keeping the same cool or freezing for consumption or temporary preservation in the open air without use of any freezing device. For example, the use of freezing mixtures principally containing ammonium nitrate has been proposed, since ammonium nitrate has a negative heat solution in water.

However, such freezing mixtures have the following disadvantages: They can not retain the freezing function for a long time upon use since rapid solution of ammonium nitrate occurs due to its extremely high solubility. Further, precautions must be taken in handling and transporting ammonium nitrate since it is a potential high explosive. The explosion of ammonium nitrate may be prevented by mixing it with another ammonium salt such as ammonium chloride or urea. However, if a mixture of ammonium nitrate and another ammonium salt is packed in the same container to keep the mixture fresh until it is put in use, the ammonium nitrate will pick up water from the another ammonium salt, resulting in the decrease of its freezing function. Even if ammonium nitrate is packed by itself, it will deliquesce graduallly upon storage and transportation if the container has any pinhole.For the reasons mentioned above, the conventional mixtures can not be used as portable freezing means.

It will therefore be an object of the present invention to provide freezing mixture compositions which retain a freezing function for a long time on use and are prevented from deliquescence upon storage and transportation.

Another object of the present invention may be to provide freezing mixture compositions, which make it possible to cool various things by the addition of water, sulphates containing water of crystallisation or ice.

Still another object of the present invention may be to provide freezing mixture compositions principally containing ammonium nitrate, which do not explode.

A further object of the present invention may be to provide a portable freezing means comprising said freezing mixture compositions.

According to the present invention, there are provided freezing mixture compositions, comprising two or more inorganic compounds selected from inorganic acid salts of ammonia, alkali metals and calcium, said inorganic compounds being in the form of crystalline or shaped particles whose surfaces are coated with a protective film forming material, the coating being sufficient to protect the said particles against deliquescence but insufficient to prevent the composition from acting as a freezing mixture when contacted with water, ice, or a salt containing water of crystallisation As inorganic compounds, there may be used those such as ammonium nitrate, ammonium chloride, ammonium sulphate, ammonium carbonate, ammonium thiocyanate, sodium chloride, sodium carbonate, sodium nitrate, sodium sulphate, potassium nitrate, potassium chloride, potassium carbonate, potassium sulphate, calcium nitrate, calcium chloride, calcium sulphate, etc.

The above inorganic compounds may be mixed in any ratio as the occasion demands.

However, if ammonium nitrate is used as one of the ingredients of the composition, another compound is preferably added thereto in an amount of 10 to 65 percent by weight.

Most of the above inorganic compounds are hygroscopic so that they will be deliquesce upon storage and transportation if they are exposed to the air. According to the present invention, the surfaces of crystalline or shaped particles of the above inorganic compounds are coated with a protective film forming material to hinder the deliquescence.

Any of the following compounds may be used as protective film forming materials: A. Polysaccarides and derivatives thereof B. Synthetic resins C. Derived proteins D. Waxes E. Fats and oils The above category A includes, without being limited to, starch, cellulose, mannan, sodium alignate, methylcellulose, carboxymethyl starch and carboxymethyl cellulose.

The above category B includes, without being limited to, polyvinyl acetals, polyurethane resins, fluorine-contained resins and silicone resins.

The above category C includes without being limited to, gelatine.

The above category D includes, without being limited to; paraffin wax and vegetable wax.

The above category E includes, without being limited to; hardened oil, glycerol ester of stearic acid and palmitic acid.

Particularly, nonhygroscopic materials are preferred as a protective film forming material since they will effectively prevent the above inorganic compounds from the deliquescence. If the monhygroscopic material such as, for example wax is used as a material for protective coatings, the coatings may preferably have a thickness of from 0.1 to 50 , particularly, from 0.1 to 13 ,a. If the protective coatings are too thin, they will not possess the protective function, and if too thick they will result in the loss of the freezing function of the composition.

After being coated with the protective film forming material, the inorganic compounds are weighed and then mixed to prepare the freezing mixture compositions.

If necessary, the compositions may contain thickening agents such as carboxymethyl cellulose, carboxymethyl starch, polyacryl amides, methyl cellulose, etc. The composition may also contain heat insulating and regenerating materials such as glass powder, granular expanded polyethylene, perlite and the like. Further, sulphate may be added to the composition.

For storage and transportation, the above composition may be packed in plastic containers. If the composition is used for portable freezing means, the composition is preferably filled in a small bag of plastic film under a reduced or atmospheric pressure.

As a material for the above bags, there may be used those such as polyvinyl chloride, polyamide resins, polyester resins, polycarbonate resins, polyethylene resins, polypropylene resins, polyurethane resins, etc.

According to the preferred embodiment of the present invention, the bag containing a freezing mixture composition has two compartments communicated each other through a small hole, one of the said compartment being filled with the composition, the other being empty and being adapted to be filled with water upon use.

As mentioned above, each ingredient of the freezing mixture composition is respectively coated with the protective film forming material, so that the composition is protected from deliquescence and rapid solution in water. Accordingly, the composition according to the present invention can retain its freezing function for a long time upon use. The composition of the present invention can be prevented from exploding if it comprises ammonium nitrate, by including other inorganic compounds which act as a explosion inhibitator. Even if the compositions of the present invention are allowed to stand for 2 years in contact with air, they possess an effective freezing function and their weight change is less than 5%.

If the compositions comprise thickening agents, heat insulating materials and/or heat regenerating materials, the heat loss due to the heat conduction may be decreased so that the freezing or cooling function of the freezing mixture may be maintained for a long time. If the compositions comprise an ingredient having a negative heat of solution in water, it is possible to use the composition for the purpose of cooling or freezing beverages, foods, etc, for consumption on outings and picnics.

The invention will be further apparent from the following description with reference to examples and several figures of the accompanying drawings.

In the drawings: Fig. 1 is a graph showing the weight change of freezing mixture composition when exposed to the air: Fig. 2 is a graph showing the influence of humidity on a freezing mixture composition; Fig. 3a is a plan view of a bag containing a freezing mixture composition; Fig 3b is a sectional view thereof; Figs. 4 and 5 show the cooling properties of the composition of the present invention; and Figure 6 is a perspective view of another embodiment of a freezing bag.

EXAMPLE 1 Using a crystalline particles of ammonium nitrate ammonium chloride and urea as main ingredients, a freezing mixture composition is prepared. The particles of the above ingredients are respectively coated with ethyl cellulose to form thin protective coatings or films of about 0.1 to 13,ii in the known manner. The above coated ingredients are respectively weighed and mixed with carboxymethyl starch, polyacrylamide and granular expanded polyethylene in the following proportion.

Coated ammonium nitrate 150 g Coated ammonium chloride 30 g Coated urea 40 g Carboxymethyl starch 8 g Polyacrylamide 0.1 g Granular expanded poly 2 g Composition 230.1 g A temperature lowering of about 20 to 27 degrees can be obtained with the above composition by adding water thereto.

In order to observe the effect of the protective coatings, the above composition is allowed to stand for 120 days in contact with air under the circumstances of a temperature of 25"C and the humidity of 60%. A weight change of the composition is shown in Fig. 1. Included in Fig. 1 for comparison is a weight change of a comparative sample having the same composition of which main ingredients are not coated. For the observation of the influence of humidity, the composition of example 1 was allowed to stand in lots for 24 hours at 25"C under various humidity levels and the comparative sample was also allowed to stand in lots for 24 hours at 100C under various humidity. The results are shown in Fig. 2.

In Figs, 1 and 2, the solid lines show the results for the composition of example 1 and the broken lines show the results for the comparative sample.

As can be seen from Fig. 1, the composition of example 1 scarcely shows weight increase even after 120 days, while the comparative sample possesses great weight increase. As can be seen from Fig. 2, when exposed to the air the temperature of the composition of example 1 is lowered owing to deliquescence, as is that of the comparative sample, but the rate of deliquescence thereof is much slower than that of the comparative sample.

As will be understood from the above, the composition deliquescence is hindered by the protective coatings even under the high humidity.

As shown in Figs. 3a and 3b, a small bag 1 of laminated plastic film is used for the preparation of a portable freezing means.

The bag 1 is heat-sealed across its width to form two compartments 2 and 3 which may communicate with each other through a passage 4 by removing a clamping means 5 upon use. The compartment 2 is filled with the composition and the other compartment 3 is kept empty during storage and transportation. The compartment 3 is provided with an opening 6 adjacent to the heat-sealed edge 7 and fitted with an exfoliatable strip 8 having an opening 6' over the opening 6. The opening 6' is closed by a pressure-sensitive adhesive film 9 to which a pressure-sensitive adhesive film 10 is adhered.

In use, after removing the adhesive film 9 together with the adhesive film 10, a certain amount of water is poured into the compartment 3 through the openings 6 and 6'. After removing the strip 8, the opening 6 is closed by the adhesive film 9, and then the clamping means 5 is removed to allow the water to flow in the compartment 2 through the passage.

In order to observe the freezing properties of the above portable freezing means, 100 g of water was poured in the bag 1 containing 100 g of the composition of example 1. The temperature of water is 15 C. The bag 1 was convered with a towel and allowed to stand in contact with the atmosphere at 250C. The temperature change of the bag 1 is shown in Fig. 4.

Another bag containing 100 g of the composition of example 1 and 100 g of water is put in an airtight box of expanded polystyrene, and the temperature change in the box was measured. The result is shown in Fig. 5.

From Figs. 4 and 5, it will be seen that the composition of the present invention retains its freezing function for a long time.

The following examples illustrates further formulations of a freezing mixture composition according to the present invention. These example should not be construed as the limitation of the scope of the invention.

Example 2 Calcium chloride coated with paraffin wax 250 g Sodium chloride coated with paraffin wax 30 g A temperature lowering of this composition is about 40 to 50 degrees when it is mixed with 100 g of ice. The composition may be used for a freezing mixture for freezing ice cream.

Example 3 Ammonium chloride coated with stearic acid ester 200 g Potassium nitrate coated with stearic acid ester 100 g Carboxymethvl starch 8 g Polyacrylamide 0.1 g Pulp sludge 10 g A temperature lowering is 32 degrees when the composition is mixed with 100 g of water. The composition may be used for a freezing mixture for cooling beverages, foods, etc.

Example 4 Ammonium chloride coated with polyacryl resin 60 g Potassium nitrate coated with polyacryl resin 100 g Sodium sulphate coated with polyacryl resin 100 g Carboxymethylcellulose 8 g Polyacrylamide 0.1 g Methylcellulose 1 g Glass powder 100 g The temperature lowering is 25 degrees when the composition is mixed with 100 g of water. The composition may be used as a freezing mixture for semen.

Example 5 Coated ammonium chloride 35 g Coated potassium nitrate 70 g Coated sodium sulphate 70 g Coated common salt 35 g The above ingredients are coated with a mixture of polyethylene and polyvinyl acetate.

The temperature lowering is 25 degrees when the composition is mixed with 100 g of water. The composition may be used as a freezing mixture for fishing. The lowest temperature of the freezing mixture is -5"C when water is added. It is also possible to obtain the lowest temperature of -28"C by the addition of ice blocks.

Example 6 Ammonium nitrate coated with hardened oil 96 g Ammonium thiocyanate coated with hardened oil 150 g Ammonium chloride coated with hardened oil 20g Carboxymethylstarch 8g Perlite or grannular, expanded polystyrene ~ 2 g The temperature lowering is 37.7 degrees when the composition is mixed with 100 g of water. If the composition is used for precooling and thermoelement, the electric efficiency of the thermoelement may be improved from about 20% to more than Example 7 Coated ammonium sulfate 50 g Coated ammonium chloride 8 g Coated urea 3 g The above ingredients are coated with a mixture of polyethylene and polyvinyl acetate. This composition may be used as a freezing mixture for cooling beverages, foods and the like for consumption on picnics. In use, the above freezing mixture composition may be added to sodium sulfate hydrate (ex.Na2SO4. 24H2O), whereby the materials are cooled to a temperature of about -5"C. In such a case, it is preferred to use an expandable bag 11 of laminated plastic film, as shown in Figure 6. The bag 11 comprises a body portion 12 composed ~ of flexible plastic film and provided with a neck member 13 to which a cap 14 is screwed. In the body portion 12, 300 g of sodium sulfate hydrate has been charged together with an insulating material such as, for example, expanded polystyrene pellets. The freezing mixture composition packed in a small bag 15 of aluminium foiled plastic film may be put into the bag 11 through a mouth thereof as occasion demands, whereby the temperature lowering occurs.Accordingly, freezing function can be obtained whenever the freezing mixture composition is put from a pack into the bag 11, and hence, it is possible to lengthen the cooling time. The freezing mixture composition may be charged in the bag previously instead of sodium sulfate hydrate.

Example 8 Ammonium nitrate coated with ethyl cellulose 100 g Ammonium chloride coated with ethyl cellulose 5 g Urea coated with ethyl cellulose 15 g In use, the above freezing mixture composition is mixed with a mixture of 100 g of sawdust or pulp sludge and 100 g of water or sodium sulfate hydrate (Na2SO4 . 24H2O). This freezing mixture composition having the above compositional proportion may be used for freezing a dead body.

WHAT I CLAIM IS: 1. A freezing mixture composition, comprising two or more inorganic compounds selected from inorganic acid salts of ammonia, alkali metals and calcium, said inorganic compounds being in the form of crystalline or shaped particles whose

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Example 3 Ammonium chloride coated with stearic acid ester 200 g Potassium nitrate coated with stearic acid ester 100 g Carboxymethvl starch 8 g Polyacrylamide 0.1 g Pulp sludge 10 g A temperature lowering is 32 degrees when the composition is mixed with 100 g of water. The composition may be used for a freezing mixture for cooling beverages, foods, etc. Example 4 Ammonium chloride coated with polyacryl resin 60 g Potassium nitrate coated with polyacryl resin 100 g Sodium sulphate coated with polyacryl resin 100 g Carboxymethylcellulose 8 g Polyacrylamide 0.1 g Methylcellulose 1 g Glass powder 100 g The temperature lowering is 25 degrees when the composition is mixed with 100 g of water. The composition may be used as a freezing mixture for semen. Example 5 Coated ammonium chloride 35 g Coated potassium nitrate 70 g Coated sodium sulphate 70 g Coated common salt 35 g The above ingredients are coated with a mixture of polyethylene and polyvinyl acetate. The temperature lowering is 25 degrees when the composition is mixed with 100 g of water. The composition may be used as a freezing mixture for fishing. The lowest temperature of the freezing mixture is -5"C when water is added. It is also possible to obtain the lowest temperature of -28"C by the addition of ice blocks. Example 6 Ammonium nitrate coated with hardened oil 96 g Ammonium thiocyanate coated with hardened oil 150 g Ammonium chloride coated with hardened oil 20g Carboxymethylstarch 8g Perlite or grannular, expanded polystyrene ~ 2 g The temperature lowering is 37.7 degrees when the composition is mixed with 100 g of water. If the composition is used for precooling and thermoelement, the electric efficiency of the thermoelement may be improved from about 20% to more than Example 7 Coated ammonium sulfate 50 g Coated ammonium chloride 8 g Coated urea 3 g The above ingredients are coated with a mixture of polyethylene and polyvinyl acetate. This composition may be used as a freezing mixture for cooling beverages, foods and the like for consumption on picnics. In use, the above freezing mixture composition may be added to sodium sulfate hydrate (ex.Na2SO4. 24H2O), whereby the materials are cooled to a temperature of about -5"C. In such a case, it is preferred to use an expandable bag 11 of laminated plastic film, as shown in Figure 6. The bag 11 comprises a body portion 12 composed ~ of flexible plastic film and provided with a neck member 13 to which a cap 14 is screwed. In the body portion 12, 300 g of sodium sulfate hydrate has been charged together with an insulating material such as, for example, expanded polystyrene pellets. The freezing mixture composition packed in a small bag 15 of aluminium foiled plastic film may be put into the bag 11 through a mouth thereof as occasion demands, whereby the temperature lowering occurs.Accordingly, freezing function can be obtained whenever the freezing mixture composition is put from a pack into the bag 11, and hence, it is possible to lengthen the cooling time. The freezing mixture composition may be charged in the bag previously instead of sodium sulfate hydrate. Example 8 Ammonium nitrate coated with ethyl cellulose 100 g Ammonium chloride coated with ethyl cellulose 5 g Urea coated with ethyl cellulose 15 g In use, the above freezing mixture composition is mixed with a mixture of 100 g of sawdust or pulp sludge and 100 g of water or sodium sulfate hydrate (Na2SO4 . 24H2O). This freezing mixture composition having the above compositional proportion may be used for freezing a dead body. WHAT I CLAIM IS:

1. A freezing mixture composition, comprising two or more inorganic compounds selected from inorganic acid salts of ammonia, alkali metals and calcium, said inorganic compounds being in the form of crystalline or shaped particles whose

surfaces are coated with a protective film forming material, the coating being sufficient to protect the said particles against deliquescence but insufficient to prevent the composition from acting as a freezing mixture when contacted with water, ice, or a salt containing water of crystallisation.

2. The composition according to claim 1 wherein said protected film forming material is selected from polysaccarides and derivatives thereof, synthetic resins, derived proteins, waxes and, fats and oils.

3. A composition according to either claim 1 or claim 2 in which the coating has a thickness of from 0.1 to 50 y.

4. The composition according to any one of the preceding claims further comprising thickening agents.

5. The composition according to any one of the preceding claims further comprising a heat insulating material and heat regenerating material.

6. A portable freezing means comprising a freezing mixture composition comprising two or more inorganic compounds selected from inorganic acid salts of ammonia, alkali metals and calcium, said inorganic compounds being in the form of crystalline or shaped particles whose surfaces are coated with a protective film forming material, said composition being filled in a small bag of plastic film.

7. The portable freezing means according to claim 6 wherein said small bag has two compartments which may communicate with each other through a passage, one of said compartments being filled with said composition, the other being empty.

8. A freezing mixture compsosition according to claim 1 substantially as described herein and exemplified by any of the Examples.

9. A pack containing a quantity of freezing composition according to any one of claims 1 to 5 or 8.

10. A pack, substantially as herein described with reference to Figures 3a and 3b of the accompanying drawings, containing a quantity of a freezing composition according to any of claims I to 5 or 8.