JPS58204082A - Cold heat-storage material - Google Patents

Abstract

PURPOSE:To provide a cold heat-storage material capable of precisely correponding to any desired temp., reusable, and causing no trouble such as leakage because of gel structure, by neutralizing and crosslinking an aq. polyacrylic acid soln. with mono- and tri-valent cations. CONSTITUTION:An aq. polyacrylic acid soln. is neutralized and crosslinked with monovalent cations (e.g., Na<+>, K<+>, NH4<+>) and trivalent cations (e.g., Al<3+>, B<3+>) to give the titled material. It is possible to obtain a heat-storage material capable of yielding a gel of extremely higher water absorbing power than others. Appropriate combination of a specific gel with inorg. neutral salts. allows the desired temp. performance and provides a cold heat-storage material excellent in economy and safety.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a reusable gel-like cooling agent.

In recent years, there has been a growing interest in cold storage due to the diversification of needs such as maintaining the freshness and preservation of food products. It is currently difficult to meet diversified needs in terms of cold temperatures, usage methods, etc.. The objective is to provide a cold storage agent that has an i+J capacity for repeated use and does not cause inconveniences such as leakage from L2 gel-like containers.

There are many ways to obtain viscous gels, but among natural polymers, agar, and gum-like synthetic polymers, polyacrylates or their rust conductors are the best.
(Although it is relatively rare, the substance is an electrolyte polymer, and its water absorption performance in ionic solutions is usually extremely reduced. However, the M solid point used in cold storage agents is The anti-F agent is an inorganic neutral salt which is superior in terms of specific heat, economy, safety, etc. (It goes without saying that a carrier gel with excellent water-absorbing properties is the best choice, but in the present invention, the polyacrylic acid aqueous solution is neutralized and cross-linked with 114 and 3 (-) ions, which is extremely effective compared to others. 0J#1 and 14 were successful in obtaining gels with excellent water absorption performance, and easily provided ah agents with various temperature characteristics.

1 A preferred embodiment of the present invention will be described below.

(Example 1) Bo+Jyri 1ifiiO% water tli 1m75g and 25g of water
After adding 2.3 g of a 48% aqueous solution of 0 g of sulium hydroxide to make a homogeneous solution, it becomes liquid puttrium aluminate.

The temperature performance of this product is as shown in Example 1 in the attached table.

(Example 2) Putrium chloride was added to the gel of Example 1 in an amount of 1.5% by weight of the gel, and the temperature performance of the resulting product was as shown in Example 2 in the attached table.

(Example 3), 250 g of water, 3 g of sodium tetraborate 1O hydrate, and 1.5 g of 48% sodium hydroxide aqueous solution were added to polyacrylic acid 10% aqueous i&7sg, and the bales of Example 1 were made into a homogeneous solution. When 9 g of liquid monolium gamma luminate is added and stirred, it immediately becomes a viscous globular material, but 50 g of potassium chloride is further added. It should be noted that the viscosity of the chloride showed almost no change when potassium chloride was added.

(Example 4) In fact, instead of potassium chloride in 113, thorium chloride 5
I added 0g, but there was no change at all 11 <, this thing'4A
The degree U#A is as shown in Example 4 in the attached table.

(Fruitful example 5) Iliu chloride in place of potassium chloride in Example 3.

Although 33 g of aluminum and 50 g of 1 lium nitrate were added, there was no change in Kel viscosity at all. The temperature performance of this product is as shown in Example III 5 in the attached table. The monovalent cation shown in the examples is sulium, but potassium or ammonium may also be used, and inorganic neutral salts such as gamma monium chloride and #i sodium may also be used. If we do, we can obtain a small V with different temperature trends for different people.

The fact that there was no change in the gel viscosity of the actual M&Examples 1 to 5 shows the specificity of the neutralized crosslinked polyacrylic acid of the present invention; Although it was found that the amount of added salts was small compared to the gel, it was found that there was a change in water adsorbed to the gel, and there was also a large difference in specific heat, etc. This is a desirable thing.

As described above, according to the present invention, a cold storage agent that has the desired temperature performance and is also excellent in economic efficiency and safety simply by appropriately combining specific Arole and inorganic neutral type #i is provided. can be obtained.

In addition, in the attached table, the sample was placed in a 200 cc beaker at 2o()g.
After freezing in a -35℃ freezer for 15 hours,
It shows the temperature transition of the cold storage agent of the present invention measured at M25°C.

Patent applicant Satsuki Kitani Eslen Kako Co., Ltd.

Claims (1)

[Claims] ■ Polyacrylic acid aqueous solution with monovalent and 311 cations' (
A gel-like cold storage agent made by neutralization and crosslinking. (2) The cold storage agent according to claim 0, wherein soluble inorganic neutral #111i is further added to the neutralized crosslinked product. ■Claim No. 0 in which ζ is used as the cation of 3 (IllI), and aluminum is used in conjunction with ζ and/or both.
The cold storage agent described in item 0 or item 0.