NL7907846A - CHEMICAL REACTION-BASED COOLING PACKAGING AND METHOD FOR MANUFACTURING SUCH COOLING PACKAGING. - Google Patents

Description

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Chemical reaction-based cooling package as well as a method of manufacturing such a cooling package.

The invention relates to a cooling package, the action of which is based on a chemical reaction and which preferably comprises two hermetically closed compartments, the first of which contains a water-endothermally soluble substance and the second a second water-endothermally soluble substance. The invention also relates to a method for manufacturing such a cooling package.

Traditionally, many different chemical packages have been known which serve to generate a cooling effect at a desired time. Such so-called refrigerated packages usually comprise two hermetically sealed compartments. One compartment contains e.g. ammonium nitrate NH4 NO3, which dissolves in water endothermically, i.e., with heat absorption. The other compartment usually contains a substance rich in crystalline water, such as e.g. contains crystal soda NA2CO3.IOH2O, as well as water in a separate bag. Both compartments are separated from each other by a hermetically sealed dividing seam. If one wishes to use the package, the intermediate seam and the bag are broken with water, so that the substances in the package can be mixed together.

As a result, the substances dissolve in water while absorbing heat and the temperature of the package even drops a few degrees. In Finnish patent application 1191/72 an example of such a package has been put forward. The presence of water is not entirely necessary due to the crystal water of the second component, but the cooling effect is then not as great.

In the known cooling packages, the chemical which releases crystal water usually consists of crystal soda NA2CO3.IO% 0. This is mainly due to the fact that crystal soda is advantageous compared to other substances and produces a relatively large cooling effect. However, the said substance also has undesirable properties when used for the known cooling packages.

When crystal soda NA2CO3.H2O is heated to above 32 ° C, it is known that it decomposes from the kahydrate into heptahydrate and, with increasing temperature, also into monohydrate. The water thus released forms a solution with heptahydrate and monohydrate. At the respective temperature, approximately 31.2% Na2 CO3 dissolves in water. When the temperature of the solution falls again, sodium carbonate crystallizes again to the hydrate according to the law of equilibrium. However, according to the same law, part of the original crystal water remains as saturated mother liquor. While some of the crystal water remains as free water, lower hydrates are also formed and the content of decahydrates remains smaller than its original content in the package. A part of the original effect of the packaging is thus permanently lost.

In practice, the aspect described above is very unpleasant when operating in tropical and subtropical climates where the daytime temperature, even in the shade, easily rises above the mentioned 32 ° C. For the operation of the cool packs, the reduction in the content of decahydrates means a decrease in effectiveness.

The crystal soda required for the known cooling packages is hardly available for technical purposes, at least for a moderate price. Therefore, if one wishes to manufacture packages in larger quantities, it is virtually indispensable to install an own crystal soda plant. In principle, crystal soda can be manufactured by a very simple method.

By mixing water and crystal anhydrous soda in a suitable ratio, soda can be dissolved in water. Dissolution takes place exothermically, i.e., with the release of heat. The temperature of the mixture thus rises slightly, generally a few tens of degrees. Crystallization takes place on cooling of the solution. The crystal soda content depends on the temperature of the solution. In an industrial-scale process, the temperature drops only slowly due to the exothermic nature of the crystallization, which may take several days. The drop in temperature can be accelerated by artificial cooling. However, the entire solution never transitions in crystal form, but saturated water, i.e. mother liquor, always remains. This mother liquor can be used several times during the process, but must then be disposed of as waste water. Therefore, unpleasant liquid wastes are formed when crystal soda is made.

The erection of the aforementioned crystal soda plant therefore requires significant investment during the erection phase. Moreover, it can be noted that although the manufacturing process of crystal soda is in principle very simple, the process can also encounter unpleasant difficulties, which are mainly related to the operation of conveyors and metering devices of the made crystal soda. This is mainly based on the fact that the crystals break easily under pressure, thereby releasing the mother liquor which bound the crystals. A heterogeneous mass then arises, the transport of which e.g. with a screw conveyor 40 can often be extremely difficult. Therefore, it is very difficult to fully automate the manufacturing process 7907846-3 and the installation requires continuous presence of operating and supervisory personnel during operation.

The aim is to avoid the drawbacks described above with the known packages with the cooling package according to the invention. This is achieved with the packaging according to the invention with the help of the properties shown in the characterization of claim 1.

That invention also includes a method of manufacturing said package. According to the invention, this method is characterized by what is shown under the characterization of claim 3.

The main advantage is that absolutely no crystal soda installation is required. This means a very large investment saving. This saves on production areas, working capital and on the number of company employees. At the same time, of course, the difficult handling and dosing of the finished crystal soda is avoided. It is not necessary to store it temporarily and trucks and transporters are not needed.

Taking the entire manufacturing process of the cooling packages into account, the liberation of the crystal soda plant also means that the limited capacity of a crystal soda plant does not limit the total production capacity. A crystal soda plant • «can of course only be planned for an approximately average production. A rapid production increase is then not possible, which would correspond to the top of the requirement. After all, the crystallization of the crystal soda is always a function of the temperature and the temperature drops only slowly during large-scale production. With regard to the production speed, cooling is a critical factor. If one is freed from the limitations of the crystal soda plant, multi-shift services can also be easily set up for other production.

The invention also achieves the important advantage that no special machine for packaging the bag with water and no dosing device is required therefor. As a result, the entire manufacturing method is simplified, which also means improvement of the operation.

If the method according to the invention is compared with the known production methods for cooling bags, it can moreover be established that the accuracy in the dosing of crystal soda according to the method of the invention, in which dosing in liquid form, is noticeably greater / clan at the known methods. It can also be determined that the use of packaging material in the method according to the invention is less.

7907846 'if -4-' ï

A special water bag is now no longer necessary and on the other hand, crystal soda in the liquid state does not take up as much space as granular crystal soda + the water bag in the known packaging. Manufacturing the package also requires less material than for the known cooling packages.

If one compares the known cooling packages with the cooling package according to the invention, a remarkable and decisive difference is striking. The cooling bag manufactured according to the invention, which therefore contains the mother liquor present in the crystallization reaction, follows the law of equilibrium under all circumstances. As a result, the package always contains only crystal soda (Na2C0g.IOH2O) and water in the ratio determined by the law of equilibrium. In other words, other hydrates cannot form. In the known packages, on the other hand, the rise in temperature to above 32 ° C causes that during the cooling of the package, a part of the crystal water released remains in the form of free water, so that a reduction in the proportion of dehydrates occurs. A crystallization of 100% occurs in the packaging according to the invention. The latter is an extremely important advantage when used in a warm climate where the temperature of the package can rise above 32 ° C.

Moreover, the absence of a special water bag offers many advantages. For the user, the cooling package manufactured according to the invention with the method is considerably more pleasant, since it does not have to break a special water bag in the package. Moreover, this is a measure which requires so much force that when using the known cooling packages this is at least perceived as difficult or unpleasant by a person of the female sex.

The absence of the water bag also indicates greater freedom for the designer of the packaging. Since one no longer has to worry about breaking the water bag inside the package, the package itself can be formed with much freedom. The dimensions and shape of the packaging can therefore be changed much more easily. The packaging manufactured by the method according to the invention can also be used considerably more versatile than the known chemical cooling packages.

The invention and the advantages obtained thereby will be explained in detail below and with reference to the appended drawing. Fig. 1 shows an embodiment of the invention,

Fig. 2 shows a second embodiment according to the invention, FIG. 3 schematically shows the method according to the invention.

7907846 -5-

According to fig. 1, the cooling package according to the invention comprises a casing 1 of e.g. plastic laminate. This casing can e.g. are manufactured by deep drawing. The laminate preferably consists of an at least one-sided weldable material on which the lid 2, which forms the other side of the package by means of a welding seam, is fixed. The entire package is thus surrounded by a welding seam 3,4 and forms a hermetically sealed space. In one end of this space is the water endothermally soluble substance 5, which preferably consists of ammonium nitrate. The compartment filled with ammonium nitrate is separated from the other compartment by means of an intermediate seam 6.

The intermediate seam 6 forms a per se known construction, consisting of a substantially circular cross-section sealing part 7 and a rod-shaped part 8 placed therein. The walls of the package surround the bar 8 while the sealing part presses those walls together. The joint is thereby hermetically closed. The space at the other end of the package contains a second water endothermally soluble substance 9. In this case, crystal soda and a saturated aqueous solution thereof are used which are in equilibrium with each other. An important part of the amount of water required for the solution of the substances is present in the form of crystal water bound in the crystal soda. Fig. 2 shows an embodiment of the packaging according to the invention which consists of a single plastic web. This was first formed into a tube by a longitudinal welding seam. The tube is then provided with a transverse welding seam 23. One end of the package contains the same chemical substance as in the previous embodiment, e.g. ammonium nitrate 25. The first compartment is then sealed by a weld 26. Compared to the other seams of the packaging, however, the welded intermediate seam is made weaker, so that e.g. pressing firmly on the packaging can burst. The manufacture of a weaker weld seam of this kind is already known per se and therefore does not fall within the scope of the present invention.

Crystal soda 29 and a saturated aqueous solution thereof are placed in the second compartment of the package. The package is then closed by welding the seam 24.

Fig. 3 shows a schematic view of an embodiment of the packaging according to the invention. The packaging material, which consists of a per se known, easily weldable plastic, is supplied from a roll 31 in the form of a continuous web. The packaging material preferably consists of e.g. polyethylene or similar material. A layered laminate can preferably also be used as packaging material, 7907846-6, wherein only the innermost layer consists of weldable material.

In the present exemplary embodiment, the packaging material 32 is supplied from a roll in a single web. Therefore, it is continuously seamed in its longitudinal direction and a tube 5 with the width of the package is produced. The longitudinal seam is made between welding jaws 33 and 34. The cover seam running transversely to the package is created between jaws 35 and 36. The required amount of NH 4 NO 3 is then dosed via a tube 37 on the bottom of the package. In between is a dosing device known per se, which is not further indicated in the schematic overview. When the total weight of the cooling package b. v. 800 grams, which is advantageous with regard to use, the package is filled with 270 grams of ammonium nitrate. The packaging is then provided with an intermediate seam. This intermediate seam can in principle be obtained using various methods. In the illustrated embodiment, a mechanical intermediate seam is used which is preferably of the same type as that described in the Finnish patent 53275 issued to the applicant. Also, the intermediate seam can be produced by welding, if desired, and care must be taken to ensure that the intermediate seam between the compartments can be broken open. Obtaining this is known per se, so that a further explanation thereof is unnecessary in this regard.

After the intermediate seam has been formed, water as well as crystal anhydrous soda Na2CO3 is introduced into the second compartment of the package. In the present example, in which a package with a total weight of 800 grams is manufactured, the water filling weight is 170 grams and that of the crystal anhydrous soda is 360 grams. In this embodiment, the water is stored in a special vessel 30. The crystal anhydrous soda is also stored in a special vessel 41. Both the water and the soda are dosed in a mixing vessel 42 in a ratio corresponding to the aforementioned amounts by weight. The mixing of the water and the crystal anhydrous soda together causes the solution of the soda to dissolve in the water. Heat is released with this solution. This is useful for the process since the crystal soda is completely dissolved in the water at a higher temperature and the crystallization takes place in known manner only after the temperature has dropped. From the mixing vessel, the warm mixture of water and soda is passed through a tube 43 into the second compartment of the package. Naturally, this tube also contains a dosing device known per se, which however does not appear in the drawing and is not further elucidated and falls outside the scope of the invention.

An advantageous further effect is achieved in that the reaction, except 7907846 -7- water and. soda small amounts of additives participate, which contribute to the crystallization of the resulting crystal soda. If only water is mixed with soda, the resulting crystal soda is usually in the form of a fairly hard clod and can complicate the use of the packaging. It is now added e.g. Add 0.9-1.0% silicon oxide to the above-described solution, then the crystal soda crystallizes out in the form of a soft crystal mass, which is jelly-like or can be reduced to a mass at least manually. Said oxide is available under the trade name "Cab-O-Sil".

After the dosing of the mixture of water and soda, the package is closed by a transverse welding seam between the jaws 35, 36. Finally, the package is cut off with the help of a cutting blade 44,45. The cut-loose package falls on the conveyor 46 and is then transported in the box 47 and therein on the loading surface in the warehouse or directly to the delivery van. It is noted that the cooling package thus produced is not ready for use as such. Immediately after packaging, the bag usually has a temperature of 40-50 ° C. After the packaging has cooled, crystallization of the crystal soda begins.

As is known, the cooling effect of the package depends on the degree of crystallization of the crystal soda and the package is thus ready for use after crystallization. In practice, this takes several days. In the meantime, the packaging can e.g. serve to heat the storage area. If required, they can also be used for heating the storage areas of the vehicles.

When the crystallization is finished, the cooling package can be put into use. One end of the package contains granular ammonium nitrate and the compartment separated by the intermediate seam contains crystal soda mixed with the mother liquor. When the intermediate seam is broken open, the two substances are mixed together on which a chemical endo-thermal reaction takes place which even lowers the temperature of the bag and of its immediate environment to about -15 ° C.

In the foregoing, the invention has been further elucidated only with respect to a particularly advantageous embodiment. It is in no way the intention to limit the invention to this, so that many other methods and materials can also be used in the manufacture of the cooling packages. In particular, it should be noted that the scope of protection also includes the manufacture of packages, the different compartments of which are kept completely separate during their manufacture and even during storage, and which are not combined until the first use of the cooling package. be touched 7907846 4? -βάθη, so that the substances inside it can connect with each other.

It is also conceivable for the compartments of the packaging to be inside one another. In such a case, preferably the Na2COg solution-containing compartment is placed inside the larger bag of ammonium nitrate to ensure easier punking.

7907846

Claims (7)

A chemical reaction-based refrigeration package, preferably consisting of two hermetically sealed compartments, the first containing a water endothermally soluble substance (5, 25) and the second containing a second water endothermally soluble substance (9, 29), characterized in that the second compartment contains a water-endothermally soluble substance in solid form (9, 29) as well as in the form of a saturated aqueous solution (10, 20) with the same equilibrium concentration * 2. Refrigerated packaging according to claim 1, the first compartment of which contains ammonium nitrate NH4NO3, characterized in that the second compartment contains crystal soda Na2CO3-10H20 and a saturated aqueous solution thereof with the same equilibrium concentration. Method for manufacturing the cooling package according to claim 1, characterized in that the first compartment of the package is filled with a water endothermally soluble Substance and hermetically sealed and the second compartment with a crystalline-free second substance and water is filled in such a proportion that the second compartment in the equilibrium state after crystallization, except the saturated aqueous solution, contains essentially only crystals with the highest content of water of crystallization. Method according to claim 3, characterized in that the water and the crystal anhydrous substance which are filled in the second compartment of the package are mixed together before filling. 5. Method according to claim 4, characterized in that the solution of the water to be filled in the second compartment and the second substance are filled at a temperature, this substance being in completely dissolved form and the crystallization of the solid substance only inside the packaging after that temperature has dropped. 6. A method according to any one of claims 3-5, characterized in that in the second compartment of the package besides water and the second substance 30, a small amount, ie 0-5¾ of an additive is added to avoid clumping of the crystal soda formed. A method according to claim 6, characterized in that the additive consists of silicon oxide in an amount of 0.9-1.0% of the total weight of the solution. 79 07 84 6 ----------------