JP2002020734A - Inorganic chloride-based snow-melting agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic chloride-based snow-melting agent which scarcely corrodes metals and has an excellent ice-melting effect and an excellent anti-freezing effect. SOLUTION: This inorganic chloride-based snow-melting agent having improved metal corrosivity, comprising an inorganic chloride and a crystalline alkali metal silicate added thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel inorganic chloride-based snow melting agent. More specifically, it is a snow melting agent that is less corrosive to metal materials, has no adverse effect on the environment, and is easy to manufacture.

[0002]

2. Description of the Related Art In winter, snow melting, ice melting agents and anti-freezing agents are sprayed on frozen or snow-covered road surfaces to prevent snow melting, ice melting or freezing (hereinafter, these are collectively referred to as snow melting agents).
Are substances having an effect of lowering the freezing point of water, for example, alkali metal salts such as calcium chloride, sodium chloride, and magnesium chloride, or halogen compounds of alkaline earth metals, other inorganic salts, sodium acetate, potassium acetate, and calcium acetate Drugs mainly containing metal salts of organic acids such as magnesium acetate, calcium acetate and magnesium acetate are used.

[0003] Among these snow melting agents, snow melting agents mainly composed of inorganic chlorides occupy most of the snow melting agents used because they have a large snow melting effect and are inexpensive. On the other hand, when inorganic chloride is sprayed on the street,
There are problems such as corrosion of metal materials such as metal parts of automobiles, guardrails and signs.

On the other hand, chromates, nitrites, phosphates, water glass, and the like are known as agents having an anticorrosion and rust-preventive effect on metal materials, and these agents are mixed with inorganic chlorides. Thus, an inorganic chloride-based snow melting agent having a rust-preventive effect may be considered.

[0005] Compounds to be compounded for this purpose include:
Chromate and nitrite, which are compounds having a rust-preventing effect on metal materials, have long been considered since ancient times, but these compounds have toxicity to animals and plants and are difficult to use as snow melting agents. Further, Japanese Patent Application Laid-Open No. 11-61095 proposes to mix a phosphate with sodium chloride and an alkaline earth metal. However, when phosphate is used, the rust-preventing effect is exhibited, but on the other hand, a problem of eutrophication of water quality caused by phosphate may occur. Therefore, use of these rust preventives is not a preferable rust preventive compounding agent as a snow melting agent when considering the effect on the environment. Next, water glass is a rust preventive agent that has little effect on the environment such as toxicity. However, water glass generally gels when mixed with an inorganic chloride such as calcium chloride, so that the rust preventive effect cannot be obtained. In order to solve this problem and obtain a sufficient rust preventive effect, Japanese Patent Application Laid-Open No. Hei 8-239647 discloses a freezing method using calcium chloride as a main component and amorphous sodium silicate (water glass) as a rust preventive. Methods for producing inhibitors have been proposed. However, the production method is to add a non-crystalline sodium silicate diluted 2 to 50 times with water to an aqueous calcium chloride solution, uniformly disperse the mixture, and then drying to obtain solid calcium chloride containing sodium silicate. Or adjusting the pH of the amorphous sodium silicate to 1 or less;
Thereafter, the sodium silicate is added to an aqueous calcium chloride solution, and the pH of the aqueous calcium chloride solution is further controlled to 5 or less, and then adjusted to neutrality, followed by drying to obtain solid calcium chloride containing sodium silicate. The disadvantage is that the production is very complicated.

Therefore, it is desired that practical snow melting agents have no toxicity to animals and plants as well as human beings, do not adversely affect the environment, and have a low cost from an economic viewpoint. Was. However, at present, no snow melting agent that can solve such a problem has been proposed.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a snow melting agent which is less corrosive to metal materials, does not adversely affect the environment, and is easy to produce.

[0008]

Means for Solving the Problems The present inventors have intensively studied to achieve the above object. As a result, it has been found that when crystalline sodium silicate is used as a rust preventive additive, the corrosiveness to metals is improved by simply mixing it with an inorganic chloride, and the present invention has been completed.

That is, the present invention is a snow melting agent comprising a crystalline alkali metal silicate and an inorganic chloride.

[0010]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, an inorganic chloride is
There is no particular limitation as long as it has an effect of lowering the freezing point of water, and it may be in any state of a solid and an aqueous solution. In the case of a solid, it is used in any state of an anhydride and a hydrate. be able to. In addition, two or more kinds of these inorganic chlorides can be used as a mixture.

Typical examples of such inorganic chlorides include calcium chloride, sodium chloride, magnesium chloride, potassium chloride, strontium chloride, lithium chloride, ammonium chloride, barium chloride, iron chloride, and aluminum chloride. Among them, calcium chloride and sodium chloride have a high snow-melting effect and are also excellent in economic efficiency, so that they can be suitably used in the present invention.

In the present invention, the silicate may be in the form of either an anhydride or a hydrate as long as it is a crystalline alkali metal silicate, but the ratio (n) of SiO ₂ to Na ₂ O of sodium silicate is 0. Those having a water content of 0 to 20% are preferred. The form of the silicate may be a solid or a slurry.

Typical examples of crystalline alkali metal silicates include alkali metal metasilicates (M ₂ Si).
O ₃ ), alkali metal orthosilicate (M ₄ SiO ₄ ), alkali metal disilicate (M ₂ Si ₂ O ₅ ), alkali metal hydrogen disilicate (MHSi ₂ O ₅ ), alkali metal tetrasilicate (M ₂ SiO ₄ ) and the like, and polyhydrates and the like, specifically, 2Li ₂ O.SiO ₂ , Li ₂ O.
SiO ₂ , Li ₂ O.2SiO ₂ , 2Na ₂ O.SiO ₂ ,
_{3Na 2 O · 2SiO 2, Na} 2 O · SiO 2, Na 2 O ·
2SiO ₂ , K ₂ O · SiO ₂ , K ₂ O · 2SiO ₂ , K ₂ O
・ 4SiO ₂ , Na ₂ O ・ SiO ₂・ 5H ₂ O, Na ₂ Si
_{O 3 · 9H 2 O, Na} 2 SiO 2 · 8H 2 O, Na 2 SiO 3
・ 6H ₂ O, Na ₂ SiO ₃・ 5H ₂ O, Na ₆ O ₃・ 13S
iO ₂ · 11H ₂ O, K ₂ O · SiO ₂ · 0.5H ₂ O, K ₂
O ・ SiO ₂・ H ₂ O 、 K ₂ O ・ 2SiO ₂・ H ₂ O 、 K ₂ O
· 4SiO ₂ · H ₂ O. These crystalline alkali metal silicates are known substances, for example, “S” published by Reinhold Publishing Corporation.
OLUBLE SILICATES Their Pr
operations ancl Uses "Volume 1 Volume 1
It is described in detail on pages 08 to 150 and the like.

The present invention is a snow melting agent comprising a mixture of these crystalline alkali metal silicates and inorganic chlorides. In this case, the alkali metal silicate is mixed with the inorganic chloride and gels, and its rust-preventing effect is not destroyed.

The inorganic chloride-based snow melting agent of the present invention can be used in a solid state or a liquid state in each of the constituent components, and the constituent form is not particularly limited as long as the inorganic chloride and sodium silicate are present simultaneously. Not restricted.

In the present invention, in addition to the above-mentioned crystalline alkali metal silicates and inorganic chlorides, other known compounds may be used as long as they do not impair the effects of the present invention for the purpose of further enhancing the rust-preventive effect and other purposes. May be added as appropriate. Examples of these substances include phosphates such as monosodium phosphate, disodium phosphate, trisodium phosphate, sodium hexametaphosphate, sodium polyphosphate, and disodium phosphite. Is
It is preferable that the ratio is about 0.1 to 30 based on 100 inorganic chlorides.

In the present invention, the method of mixing each component is not particularly limited, and the form of the obtained snow melting agent may be solid or liquid.

To illustrate such a form, in the case of a solid state,
A simple mixture of inorganic chloride and sodium silicate (hereinafter simply mixture), and a mixed granule of inorganic chloride and sodium silicate (hereinafter, mixed granule).

In the case of a liquid, a slurry in which sodium silicate is suspended in an aqueous solution of inorganic chloride (hereinafter, referred to as a mixed slurry) is exemplified.

When the inorganic chloride-based snow melting agent of the present invention is used as a solid, its shape is preferably in the form of particles, and the average particle diameter is not particularly limited.
-20 mm, more preferably 2-10 mm.

In the production of the inorganic chloride-based snow melting agent of the present invention, known means can be appropriately employed according to the above-mentioned form. For the simple mixing, a method of mixing the inorganic chloride and sodium silicate in a solid state (Production Method 1) is suitably adopted.

In order to obtain a mixed granule, a method of mixing inorganic chloride and sodium silicate in a solid state and then granulating the mixture (production method 2) is suitably employed.

In the case of preparing a mixed slurry, a method of mixing the inorganic chloride and sodium silicate while dissolving them in the presence of water (production method 3) is preferably employed.

The mixing in the above production method 1 includes a kneader, a shaker, a double cone mixer, a V mixer, a spherical mixer,
The mixing can be carried out using a generally known mixing device such as a mold mixer, a ribbon mixer, a pot mixer, a super mixer, a universal mixer, a cutter mixer, a Henssel mixer, a kneader, a ball mill, a pot mill, and a tumbling granulator. For the introduction of each component into the mixing apparatus, first, the entire amount of the inorganic chloride may be added and sodium silicate may be added thereto, or conversely, the entire amount of sodium silicate may be added first, and then the inorganic chloride may be added thereto. It is also possible to simultaneously add inorganic chloride and sodium silicate.

Next, in the mixed granulation in the above-mentioned production method 2, after mixing the inorganic chloride and sodium silicate in the above-mentioned production method 1,
It can be carried out using a generally known granulation apparatus such as a compression granulator, an extrusion granulator, and a tumbling granulator.

In the above-mentioned production method 3, an inorganic chloride and sodium silicate are mixed in the presence of water with a kneader, a shaker, a double cone mixer, a V mixer, a spherical mixer, an I mixer, a ribbon mixer. The mixing can be carried out using a generally known mixing apparatus such as a pot mixer, a super mixer, a universal mixer, a cutter mixer, a Hensel mixer, a kneader, a ball mill, a pot mill, a tumbling granulator and the like.

In this case, the crystalline silicate may be added to the aqueous solution of the inorganic chloride, or the inorganic chloride may be added to the aqueous solution or the suspension of the silicate. It is also possible to mix as a suspension. In any case, the amount of water to be added should be between 10 and 5
The amount is preferably 0% by weight from the viewpoint of achieving both the effect of the snow melting effect and the ease of mixing with sodium silicate, and more preferably 20 to 40% by weight.

[0028]

The present invention will now be described with reference to Examples.
It is not limited to these examples.

In this example and the comparative example, the snow-melting effect of the snow-melting agent was measured by putting 200 g of water in a plastic container having a diameter of 110 mm, cooling to −10 ° C., ice-cooling, and then reducing the temperature. In addition, the amount of snow melting agent is 10
g of the dispersion liquid was uniformly spread on ice, and the weight of the liquid (water) after 1 hour was measured.

The amount of metal corrosion was determined by the following method.

A solution containing a predetermined amount of a rust inhibitor at a liquid temperature of 25 ° C.
A 150% by weight aqueous solution containing a snow melting agent was prepared. Then, immersed in isopropyl alcohol and degreased 60 × 4
The weight of an iron plate (ss-400) having a size of 0 × 2.5 mm was measured, and the iron plate was immersed in a 3% calcium chloride aqueous solution. After a lapse of 7 days, rust adhering to the iron plate was removed with a # 1200 sandpaper, and the weight of the iron plate was measured.
At the same time, the weight of the iron plate before and after immersion was measured using a 3% by weight aqueous solution of a snow melting agent (blank) to which no rust inhibitor was added. Then, as the ability evaluation of the rust preventive agent, the amount of corrosion and the rust preventive rate were obtained. [Corrosion amount: MDD] = [Fe elution amount (mg) / area (dm ² )
・ Time (1 day)] [Rust prevention rate] = [(weight difference before and after immersion of blank)-(weight difference before and after immersion of iron plate) / (weight difference before and after immersion of blank)] x 100%

Example 1 To 100 parts by weight of calcium chloride, 5 parts by weight of crystalline sodium silicate (Na ₂ O.nSiO ₂ , n = 2) was added, and 3% by weight was added.
A calcium chloride aqueous solution was prepared, and the rust-preventing effect of crystalline sodium silicate (Na ₂ O · nSiO ₂ , n = 2) was evaluated by the above method. The results are shown in Table 1.

Examples 2 to 4 0.1, 10 and 50 parts by weight of crystalline sodium silicate (Na ₂ O · nSiO ₂ , n = 2, manufactured by Clariant Tokuyama: SKS-6) based on 100 parts by weight of calcium chloride The rust-preventive effect of crystalline sodium silicate (Na ₂ O.nSiO ₂ , n = 2) was determined in the same manner as in Example 1 except that the rust-preventive effect was changed to. The results are shown in Table 1.

Example 5 To 100 parts by weight of sodium chloride, 5 parts by weight of crystalline sodium silicate (Na ₂ O.nSiO ₂ , n = 2) was added, and 3% by weight was added.
A calcium chloride aqueous solution was prepared, and the rust-preventing effect of crystalline sodium silicate (Na ₂ O · nSiO ₂ , n = 2) was evaluated by the above method. The results are shown in Table 1.

Example 6 To 100 parts by weight of calcium chloride, 3 parts by weight of crystalline sodium silicate (Na ₂ O.nSiO ₂ , n = 2, 20% water) was added to prepare a 3% by weight aqueous solution of calcium chloride. The rust preventive effect of crystalline sodium silicate (Na ₂ O · nSiO ₂ , n = 2, water 20%) was evaluated by the above method. The results are shown in Table 1.

Examples 7, 8 Example 4 was repeated except that 100 parts by weight of calcium chloride was changed to 5 and 7 parts by weight of crystalline sodium silicate (Na ₂ O.nSiO ₂ , n = 2, 20% water). The rust-preventing effect of crystalline sodium silicate (Na ₂ O · nSiO ₂ , n = 2, water content 20%) was determined in the same manner as described above. The results are shown in Table 1.

Comparative Example 1 The amount of corrosion of a 3% by weight aqueous solution of calcium chloride was evaluated by the above method. As a result, the corrosion amount was 14.0 MDD.

Comparative Example 2 The corrosion amount of a 3% by weight aqueous solution of sodium chloride was evaluated by the above method. The results are shown in Table 1.

Comparative Example 3 To 100 parts by weight of calcium chloride, 5 parts by weight of amorphous sodium silicate (Na ₂ O.nSiO ₂ , n = 3, commercially available JIS No. 3 sodium silicate) was added, and a 3% by weight aqueous solution of calcium chloride was added. Adjusted to obtain amorphous sodium silicate (Na ₂ O · nSiO ₂ , n =
The rust prevention effect of 3) was evaluated by the above method. The result is
The results are shown in Table 1.

Comparative Example 4 10 parts by weight of amorphous sodium silicate (Na ₂ O.nSiO ₂ , n = 3) was added to 100 parts by weight of calcium chloride, and a 3% by weight aqueous solution of calcium chloride was prepared. The rust-preventing effect of sodium silicate (Na ₂ O · nSiO ₂ , n = 3) was evaluated by the above method. The results are shown in Table 1.

Table 1 summarizes the results of the above Examples and Comparative Examples. The snow melting agent of the present invention shown in each of the examples is composed of crystalline sodium silicate (Na ₂ O · nSiO ₂ , n = 2) and crystalline sodium silicate (Na ₂ O · nSiO ₂ , n = 2, 20% water) In comparison with the snow melting agent of Comparative Example 1 containing no calcium chloride and sodium chloride of Comparative Example 2 alone, the corrosiveness to the metal material was significantly improved. In addition, the inorganic chloride-based snow melting agents of the present invention shown in each of the examples are comparative examples 3 and 4 using amorphous crystalline sodium silicate (Na ₂ O · nSiO ₂ , n = 3) as a rust preventive. The rust prevention effect showed a higher value than that of.

[0042]

[Table 1]

[0043]

The snow-melting agent of the present invention has a large snow-melting effect, low corrosiveness to metals, has an excellent ice-melting effect and an anti-freezing effect which do not adversely affect the environment, and can be produced very easily.

Claims (5)

[Claims] 1. A snow melting agent comprising a crystalline alkali metal silicate and an inorganic chloride. 2. The inorganic chloride-based snow melting agent according to claim 1, wherein the inorganic chloride is calcium chloride and / or sodium chloride. 3. The inorganic chloride-based snow melting agent according to claim 1, wherein the crystalline alkali metal silicate is sodium silicate. 4. The crystalline alkali metal silicate salt is Na ₂ O · nSi.
O ₂ of formula (where, n = 0.5 to 3) crystalline inorganic chloride based snow melting agent according to claim 1 is a sodium silicate having a. 5. The amount of the alkali salt of silicic acid is 10 or less.
The amount is 0.1 to 50 parts by weight with respect to 0 parts by weight.
The described inorganic chloride-based snow melting agent.