JPH0797215A - Active antimony oxide and its production - Google Patents

Abstract

PURPOSE:To obtain a specific active antimony oxide by dissolving antimony trioxide in an acid, adding an alkali and an oxidizing agent to the solution or adding an excessive amount of an alkali, and by heat-treating. CONSTITUTION:1mol of antimony trioxide is dissolved in 1-8 equivalent of an acid (e.g. hydrochloric acid) per 1mol and then 1-5 equivalent of an excessive alkali (e.g. caustic soda) to 1 equivalent of acid in the solution and 0.5-4 equivalent of an oxidizing agent (e.g. sodium hypochlorite) to 1mol of antimony trioxide are added to the solution or an extremely excessive amount of an alkali is added to the solution. After that, the solution is heat-treated at 40-100 deg.C to partially oxidize antimony. The prepared product contains 0.5-5wt.% of the antimony pentoxide which is formed by partial oxidation of antimony trioxide and also contains alkali metal oxide and hydroxide and an alkali metal compound of an inorganic acid salt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to active antimony oxide and a method for producing the same, and is used as a curing agent when producing a white or light-colored polysulfide rubber composition widely used as a sealing agent for civil engineering and construction. The present invention relates to an active antimony oxide and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, lead dioxide or manganese dioxide has been used as a curing agent (for a two-component type) for polysulfide rubber. However, since lead dioxide and manganese dioxide are blackish brown powder, when the polysulfide compound is cured with these curing agents, they are colored with the color of the curing agent itself,
A white cured product could not be obtained. Therefore, a curing agent has been studied for the purpose of obtaining a white polysulfide rubber. For example, a method of adding a large amount of titanium white to lead dioxide or manganese dioxide to lighten it is used.

Further, in Japanese Patent Publication No. 38-23478, calcium peroxide activated by water is used as a curing agent, and in Japanese Patent Publication No. 47-34448, an organic amine is added and mixed with zinc peroxide. A method for curing the liquid polysulfide polymer used as described above is described. Further, in Japanese Examined Patent Publication No. 38-23478, an example of using antimony trioxide as a curing agent is described only in Comparative Example 1, and the curing rate is delayed with antimony trioxide and antimony pentoxide. It is stated that it is not practical.

As the antimony oxide, there are known a method for producing antimony trioxide by a dry oxidation method of a metal, a method for oxidizing a nitric acid of a metal, and a method for producing antimony pentoxide by a wet oxidation method of antimony trioxide. Although the purpose of use is different as a method for producing antimonic acid, there is a method for producing crystalline antimonic acid by heat-treating alkali hexahydroxoantimonate in JP-B-45-6695 and antimony trioxide in JP-A-62-153123. A method for synthesizing vitreous antimonic acid by wet-oxidation of is described.

[0005]

However, the method of adding titanium white causes masking failure,
There is a problem that the specific gravity is increased due to the increase of the amount of the additive and the sagging occurs at the time of coating application. Even in the method using calcium peroxide or zinc peroxide and an organic amine, it takes a long time to cure the polysulfide rubber at room temperature, which is a problem in use. Antimony trioxide, antimony pentoxide, and antimonic acid obtained by a known production method did not act as a curing agent and were not practical.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to prevent coloring by the color of the curing agent itself such as lead dioxide or manganese dioxide. It is an object of the present invention to provide activated antimony oxide exhibiting a white color and a method for producing the same, as a curing agent that does not inhibit the room temperature curing of polysulfide rubber.

[0007]

The active antimony oxide according to the present invention was developed in view of the above-mentioned conventional problems, and the gist of the invention is to oxidize a part of antimony trioxide. Antimony pentoxide is mixed, and the composition of the antimony pentoxide is in the range of 0.5 to 5% by weight with respect to antimony trioxide, and an alkali metal oxide, hydroxide or inorganic acid salt is used. It is active antimony oxide characterized by containing a metal compound.

Further, the gist of the invention of the method for producing active antimony oxide according to the present invention is to dissolve antimony trioxide with an acid and then add an alkali and an oxidizing agent to the solution, or to dissolve the solution. A method for producing active antimony oxide is characterized in that antimony is produced by partially oxidizing antimony by heating after adding an excess alkali to the solution.

In particular, in the present invention, as a result of intensive studies in view of the above-mentioned conventional problems, antimony pentoxide obtained by oxidizing a part of antimony trioxide is used as an oxidizing agent for a white or light polysulfide rubber composition. It has been found that active antimony oxide mixed with an alkali metal compound is extremely effective. That is, antimony trioxide is dissolved with an acid, and an alkali and an oxidizing agent are added to the solution, or an excess amount of alkali is added to the solution, and then heat treatment is performed to remove antimony. It is an active antimony oxide produced by partial oxidation and further neutralization, washing with water, filtration and drying, and a method for producing the active antimony oxide.

[0010]

The active antimony oxide according to the present invention is prepared by dissolving a part or all of antimony trioxide with an acid and adding an alkali and an oxidizing agent to the solution, or adding an excess amount to the solution. It is produced by partially heating antimony after adding alkali of the above, and it shows a curing action at room temperature for a short time as a curing agent for polysulfide rubber, and the polysulfide rubber after curing is white or light colored. Is very effective in exhibiting.

In the present invention, as described above, antimony trioxide is dissolved with an acid, and an alkali and an oxidizing agent are added to the solution, or an excess amount of alkali is added to the solution. The manufacturing method in which heat treatment is performed thereafter can oxidize a part of the antimony trioxide, and is effective in producing the oxidized antimony pentoxide in the range of 0.5 to 5% by weight. Further, the generated precipitate can be washed with water a small number of times to leave the alkali metal in the active antimony oxide obtained.

The antimony oxide obtained according to the present invention comprises antimony trioxide (Sb ₂ O ₃ ), partially oxidized antimony pentoxide (Sb ₂ O ₅ ) and alkali metal compounds (eg, NaOH, NaCl). It is a composition. When Sb ₂ O ₃ is generated by Sb ₂ O ₅ is oxidized, Sb (III) and it is known that Sb ₂ O ₄ generates coexist Sb (V) [D.Rogers, ACSkapski, Proc.
Chem.Soc., 400 (1964)], and further Na ⁺ , Cl ⁻ , H ₂
When O is present, Na [Sb (OH) ₆ ], Na [S
It is also known to produce bCl _6-n (OH) _n ] [Comprehensive Inorgranic Chemistry, Ed. JCBa
ilar, Jr., 2,683, Pergamon Press. (1973)].

Na [SbCl _{6 -n} (OH) _n ] undergoes two-electron oxidation in the presence of a reducing substance, and Na ₃ [SbC]
l _6-n (OH) _n ], which easily absorbs oxygen in the air and is oxidized to form Na [SbCl _6-n (OH)].
Return to _n ]. Therefore, polysulfide rubber [general formula H
S- (RSS) -nRSH] is separated from [R] of the terminal thiol group [RSH] by the above-mentioned oxidation action to [R].
SSR] bond is formed to increase the molecular weight. An example of the oxidation mechanism is shown by the following reaction formula. 2 (-RSH) + Na [SbCl6 _-n (OH) _n ] +2
NaOH → (RSSR) + Na ₃ [SbCl _6-n (OH) _n ] +
2H ₂ O

On the other hand, the reduced Sb (III) complex is oxidized by oxygen in the air. The mechanism is shown as follows. Na ₃ [SbCl _6-n (OH) _n ] + H ₂ O + 1 / 2O
₂ → Na [SbCl _6-n (OH) _n ] +2 NaOH

These series of reactions consist of Sb (III) and Sb
Only when (V) coexists, only Sb ₂ O ₃
Or it is not seen when only Sb ₂ O ₅ is present.
This is summarized and simplified, and is expressed as follows. Sb ₂ O ₄ → Sb ₂ O ₃ + 1 / 2O ₂ 2 (-RSH) + 1 / 2O ₂ → (RSSR) + H ₂ O Sb ₂ O ₃ + 1 / 2O ₂ → Sb ₂ O ₄

That is, Sb ₂ O ₄ exhibits activity as a catalyst, and in the presence of an alkali metal compound, the activity is maintained by the valence transfer of antimony ions and the circulation mechanism restored by oxygen in the air, and the polysulfide rubber is cured. The reaction is promoted. This is called active antimony oxide.

[0017]

EXAMPLES The method for producing active antimony oxide according to the present invention aims at a method for producing active antimony oxide which is extremely effective as a curing agent particularly when producing a white or light-colored polysulfide rubber composition, The specific example is as follows. That is, in the production method according to the present invention, antimony trioxide is dissolved in 1 to 8 equivalents of acid with respect to 1 mol thereof, and then 1 to 5 equivalents of excess alkali is added to 1 equivalent of acid in the solution. And 0.5 to 4 equivalents of an oxidizing agent are added to 1 mol of antimony trioxide, or
Alternatively, it is a method in which a large excess of alkali is added to the solution and then the solution is heat-treated at 40 to 100 ° C. to partially oxidize antimony in the solution to produce the solution.

As a result of many years of research, the present inventors have discovered that active antimony oxide is extremely effective as a curing agent when producing a white or light-colored polysulfide rubber composition. The reason why such active antimony oxide is extremely effective as a curing agent in producing a white or light-colored polysulfide rubber composition is that active antimony oxide is a partial oxidation of antimony trioxide by an oxidizing agent and oxygen in the air. Since it is made of a mixture of antimony trioxide and antimony pentoxide, the delicate ratio is considered to have a great influence on the role of curing the white or light-colored polysulfide rubber composition.

Further, in order to mass-produce active antimony oxide which is hardened as such a hardener in a stable state easily and surely, after dissolving a part or all of antimony trioxide with an acid, an excess amount of alkali is used. It was also invented that it can be produced by adding an oxidizing agent and an oxidizing agent, or by adding an excessive amount of alkali, and then performing heat treatment at a predetermined temperature.

As the acid used in the present invention, for example, sulfuric acid, nitric acid, hydrochloric acid or the like is used, and the addition amount is preferably 1 to 8 equivalent moles per 1 mole of antimony trioxide. Examples of the alkali include sodium carbonate, caustic soda,
Caustic potash, aqueous ammonia, etc. are used, and the addition amount thereof is preferably 1 to 5 equivalent molar excess with respect to 1 equivalent of acid. As the oxidizing agent, various oxidizing agents can be used, for example, sodium perchlorate, potassium perchlorate, sodium permanganate, potassium permanganate, sodium hypochlorite, potassium hypochlorite, ammonium persulfate and peroxide. Hydrogen or the like is used.

At this time, the amount of the oxidizing agent added can be within the range of 0.5 to 4 equivalent moles per 1 mol of antimony trioxide, and preferably 0.5 to 2 equivalent moles. In the above examples, an example using an alkali and an oxidizing agent has been described. However, without using an oxidizing agent, 5 equivalent moles or more of excess alkali is added and heat treatment is performed to remove antimony. It can also be manufactured by partial oxidation. The antimony trioxide used for producing the active antimony oxide may be any antimony trioxide obtained by a conventional dry method or wet method. Also, in the case of completely dissolving antimony trioxide with an acid, antimony (II
I) Solutions can be used, eg antimony trichloride solution.

A paste prepared by mixing the active antimony oxide obtained by the present invention with the same amount of dibutyl phthalate (DBP) or chlorinated paraffin was used as a polysulfide rubber (trade name; Toray Thiokol, trade name; Thiocol LP- 32) / 100 parts, 16 parts were added, both were thoroughly mixed, and the curing rate was measured with a gel timer manufactured by Ueshima Seisakusho under the conditions of 20 ° C. RH55 ± 5%.
It was observed that the curing time was within 1 hour and the curing was extremely fast. The values of the above-mentioned curing time are comparable to those of lead dioxide and manganese dioxide, which are conventionally known curing agents for polysulfide rubber. Further, the color thereof is white as compared with black-brown lead dioxide and manganese dioxide, and therefore, it is suitable for producing a white or light color composition.

[0023]

Example-1 Antimony trioxide / 1 mol was dispersed in water, and hydrochloric acid / 2 mol was added thereto to partially dissolve it. After further adding caustic soda / 5 mol, the mixture was heated at 90 ° C. Then, it was washed several times with water, dried at 105 ° C., and then pulverized. As a result of curing the polysulfide rubber using the obtained antimony oxide, a white polysulfide rubber composition could be produced. The curing time was 13 minutes.

Example-2 Antimony trioxide / 1 mol was dispersed in 1 L of water, and hydrochloric acid / 3 mol was added thereto to partially dissolve it.
After further adding caustic soda / 4 mol, sodium hypochlorite (effective chlorine amount 10%) / 0.5 L was added, and the mixture was heated at 70 ° C. Then, it was washed three times with water, filtered, dried at 100 ° C., and then pulverized. As a result of curing the polysulfide rubber using the obtained active antimony oxide, a white polysulfide rubber composition was obtained. The curing time was 15 minutes.

[0024]

[Comparative Example-1] Without using an oxidizing agent, other conditions are

Reaction was carried out in the same manner as in Example 2 to obtain antimony oxide. As a result of curing the polysulfide rubber using this antimony oxide, the curing time was 200 minutes. From this, it was confirmed that when the excess amount of the alkali to be added was reduced, the curing activity for the polysulfide rubber was lowered because the partial oxidation was incomplete unless the oxidizing agent was added.

[Comparative Example-2] As a result of curing the polysulfide rubber using a commercially available antimony trioxide (dry method), it was confirmed that even the viscosity did not increase and there was no curing activity.

[0025]

[Comparative Example-3] Even when a commercially available antimony pentoxide is used,

No curing activity was observed as in Comparative Example-2.

[Example-3]

Using the active antimony oxide prepared in Example 1, a cured product sheet of polysulfide rubber was prepared and a heat resistance test was conducted.

The results were good as shown in [Table-1]. Margin below

[0026]

[Table-1] Heat resistance experiment

[0027]

Examples 4,5, and

[Comparative Examples 4,5]

Active antimony oxide A produced in Examples-1 and 2;
A paste / 16g in which B was mixed with the same amount of chlorinated paraffin was added to Thiocol LP-100g and cured, and the color of the cured product was visually observed. For comparison, the same observations were made for lead dioxide and manganese dioxide, and the results were as shown in [Table 2] below. Margin below

[0028]

[Table-2] Color of cured product

[0029]

Since the method for producing active antimony oxide according to the present invention has the above-mentioned constitution and action, the active antimony oxide which can be used as a curing agent for a white or light polysulfide rubber composition is simple. It is possible to economically manufacture a large amount in a stable state by various manufacturing processes. Further, the active antimony oxide produced according to the present invention is extremely active and is extremely effective as a curing agent when producing a white or light-colored polysulfide rubber composition.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidetoshi Mochizuki 2-20-5 Shimotani, Taito-ku, Tokyo Within Nippon Kagaku Kogyo Co., Ltd. (72) Inori Masanori Yanagi 2-20 Shitaya, Taito-ku, Tokyo -5 Inside Nippon Kagaku Kogyo Co., Ltd. (72) Inventor Seiyo Ozaki 6-31-13 Aobadai, Ichihara-shi, Chiba (72) Inventor Kiyoshi Watanabe 2-10-1, Nekomi, Urayasu-shi, Chiba Toray Dainiura Anritsu 301

Claims (2)

[Claims] 1. An antimony trioxide is mixed by oxidizing a part of antimony trioxide, and the antimony pentaoxide has a composition in the range of 0.5 to 5% by weight with respect to the antimony trioxide, and is composed of an alkali metal. An active antimony oxide containing an alkali metal compound selected from oxides, hydroxides and inorganic acid salts. 2. An antimony trioxide is dissolved with an acid, and then an alkali and an oxidizing agent are added to the solution, or an excess amount of alkali is added to the solution, followed by heat treatment. A method for producing active antimony oxide, characterized in that antimony is partially oxidized to produce the antimony oxide.