JPH047384B2 - - Google Patents

Description

Detailed Description of the Invention The present invention uses M ₂ O (M is an alkali metal) as an alkali metal and M′O (M′ is an alkaline earth metal) as an alkaline earth metal, singly or in combination, to form pentoxides. The present invention relates to an antimony pentoxide flame retardant containing antimony (Sb ₂ O ₅ ) in a molar ratio of 0.4 to 0.8 and having an antimony pentoxide structure, and a method for producing the same.

Sodium antimonate and antimony pentoxide can greatly increase the transparency of halogen-containing vinyl resins and halogen-free resins such as polyethylene, polycarbonate, polyester, and ABS resins when used alone or in combination with halogen-based flame retardants or adjacent flame retardants. The resin can be made flame retardant without deterioration. However, since their flame retardancy is lower than that of antimony trioxide, various proposals have been made to improve the flame retardancy of sodium antimonate and antimony pentoxide.

U.S. Patent No. 3,892,667 describes a method for pulverizing sodium antimonate, and Japanese Patent Publication No. 47-36863 describes a method for pulverizing sodium antimonate to 0.1 to 8μ.
Proposals have been made to improve the flame retardancy of sodium antimonate by partially neutralizing it with acid, but it is not practical because sodium antimonate has very poor crushability and cannot be easily pulverized. Since the bond between antimony oxide and sodium, that is, the -Na-O-Sb- bond is strong, sufficient flame retardancy cannot be obtained even if it is pulverized.

JP-A-56-59851 describes that flame retardancy can be significantly improved by separating, drying, and pulverizing a mixture of antimony pentoxide and sodium antimonate produced by the reaction of sodium antimonate with an acid. There is. This mixture of antimony pentoxide and sodium antimonate (with a sodium content of 40 mol% or less) exhibits considerably better flame retardancy than sodium antimonate, but has poor crushability.
It has drawbacks such as impairing the thermal stability and weather resistance of the resin.

JP-A-52-123977 proposes a method for producing antimony pentoxide powder by spray-drying an aqueous antimony pentoxide sol, but it is difficult to obtain fine powder of 5μ or less by spray-drying. However, it has drawbacks such as high manufacturing cost and loss of the main properties of the resin.

In recent years, it has become increasingly important to make plastics and fibers flame retardant, and with the diversification of demand, the demand for flame retardants that do not reduce the transparency or colorability of resins has become extremely large.

The present inventors have demonstrated that the synthetic resin exhibits good flame retardancy without impairing its main properties such as tensile strength, impact strength, moldability, thermal stability, and weather resistance, and without reducing its transparency or colorability. As a result of intensive research into a method for producing a flame retardant fine powder whose main component is antimony pentoxide at low cost, we found that by using sodium antimonate as a raw material, adding an organic base or its salt to it and reacting it with an acid. It has been found that a flame retardant satisfying the object of the present invention can be produced by adding an alkali hydroxide or an alkaline earth hydroxide to the obtained antimony pentoxide gel, followed by separation, drying, and pulverization.

The reaction of sodium antimonate with acid produces colloidal ammotine pentoxide, which rapidly and strongly aggregates and precipitates as antimony pentoxide gel, usually larger than 10 microns. This gel is hard and difficult to crush, so in order to obtain fine antimony pentoxide powder, the agglomeration must be weakened.
It is necessary to reduce the size of the gel.

The present inventors have discovered that organic bases such as amino and quaternary ammonium hydroxide are adsorbed on the surface of antimony pentoxide colloid and suppress colloid aggregation, so that when reacting sodium antimonate with an acid solution, It has been found that the size of the antimony pentoxide gel produced can be reduced by adding 0.5 to 20% by weight of an organic base or its salt to sodium antimonate.

The antimony pentoxide gel obtained by the above reaction was separated, washed, and dried at room temperature to 270°C, and the molar ratio of sodium to antimony was 0.05 to 270°C.
0.4, but it has the structure of antimony pentoxide hydrate (Sb ₂ O ₅ 4H ₂ O), and X-ray diffraction reveals that it is sodium antimonate hydrate (Na ₂ O 4H 2 O).
No peak of SbO ₅ 6H ₂ O) is observed. Further, the antimony pentoxide gel dried at 270° C. or higher has an antimony pentoxide structure, and no diffraction peak of sodium antimonate anhydride (Na ₂ O.Sb ₂ O ₅ ) is observed.

In addition, the dried antimony pentoxide gel obtained by the above reaction has good pulverizability, and the pulverized product shows good flame retardant effects, but since antimony pentoxide is a solid acid, antimony pentoxide addition is not necessary. This has the disadvantage that the main properties of the synthetic resin are impaired.

The present inventors separated the antimony pentoxide gel produced by the above method by suction filtration, centrifugal filtration, filter press, etc., washed it with sufficient water, and then dispersed it in water to obtain an antimony pentoxide gel slurry. After heat-forming at 50 to 100°C, the alkali metal or alkaline earth metal hydroxide is added to the alkali metal or alkaline earth metal alone or as a mixture at a molar ratio of 0.4 to 0.86 to antimony pentoxide.
It has been found that the above-mentioned drawbacks can be improved by adding the above-mentioned components so as to give the following properties and drying after separation.

That is, in the present invention, the alkali metal is M ₂ O (M is an alkali metal), the alkaline earth metal is M'O (M' is an alkaline earth metal), and antimony pentoxide (Sb ₂ O ₅ ), it is contained in a molar ratio of 0.4 to 0.8, and relates to an antimony pentoxide flame retardant having an antimony pentoxide structure.

In addition, in a method for obtaining a flame retardant from sodium antimonate and an inorganic substance, (a) dispersing sodium antimonate in water, adding 0.5 to 20% by weight of an organic base or its salt to the sodium antimonate, 1.5 to 5 stoichiometric amounts of sodium antimonate
(b) This gel is filtered, washed with water, and dispersed in water for 50 to
(c) This is then treated with an alkali metal hydroxide and/or
Alternatively, it consists of steps (a) to (c) of adding salt, alkaline earth metal hydroxide and/or salt, each singly or in combination, and drying and pulverizing this after filtration. _M2O (M
is an alkali metal), and an alkaline earth metal M′O
(M′ is an alkaline earth metal), each alone or in combination, is contained in a molar ratio of 0.4 to 0.8 to antimony pentoxide (Sb ₂ O ₅ ), and has an antimony pentoxide structure. This invention relates to a method for producing an antimony oxide flame retardant.

Since antimony pentoxide is an inorganic ion exchanger, the above-mentioned antimony pentoxide to which the alkali metal and alkaline earth metal hydroxides have been added is prepared by converting the alkali metal and alkaline earth metal into M ₂ O and M′O, respectively. 0.4 to antimony oxide molar ratio
Despite containing 0.8%, it maintains its antimony pentoxide structure. Therefore, the flame retardancy of the resin does not decrease, the acidity of antimony pentoxide is significantly reduced, so the main properties of the resin are not impaired, and the refractive index of antimony pentoxide is increased due to the increase in alkali metals and alkaline earth metals. Because of this, it does not reduce the transparency of the resin and exhibits better transparency than antimony pentoxide with a sodium content of 40 mol% or less.

In addition, in the reaction of sodium antimonate acid, if the amount of acid is lower than the stoichiometric amount of sodium antimonate, the sodium content will be over 40 mol%, but the products will be antimony pentoxide hydrate and sodium antimonate hydrate. Since it is a mixture of hydroxides, its flame retardancy is lower than that of antimony pentoxide.

The antimony pentoxide of the present invention containing an alkali metal and an alkaline earth metal in a molar ratio of 0.4 to 0.8 as M ₂ O and M'O to antimony pentoxide has very good crushability, It can be easily made into a fine powder of 0.5 to 5μ by grinding with a pin disc mill.

In the present invention, sodium antimonate as a raw material can be produced either at high temperature or by a wet method, and the acid used is a monovalent or divalent inorganic acid such as hydrochloric acid, nitric acid, sulfuric acid, or sulfamic acid. Organic acids and phosphoric acid are not preferred.

In the reaction between the sodium antimonate of the present invention and the above acid aqueous solution, the concentration of sodium antimonate is determined by the concentration of anhydrous antimony pentoxide (Sb ₂ O ₅ ) in the reaction solution.
If it is less than 2% by weight, the production amount of antimony pentoxide gel will decrease and it is not economical, and if it is more than 35% by weight, the solid content in the liquid will be more than 50% by weight. Therefore, the reaction becomes non-uniform, which is not preferable.

In the reaction of the sodium antimonate of the present invention with the above acid aqueous solution, the acid concentration is in a stoichiometric ratio of acid/sodium antimonate of 1.5 to 5.
When the acid/sodium antimonate ratio is less than 1.5, the reaction proceeds satisfactorily, but even if an organic base is added, the size of the aggregates cannot be reduced, and when it is more than 5, the antimony pentoxide gel formed is peptized during washing. Productivity deteriorates because it is washed away into the filtrate. acid/
Sodium antimonate ratio is 1.5 in stoichiometric ratio
~3 is preferred.

In the present invention, the organic bases added during the reaction of sodium antimonate and acid include amines such as monoethanolamine, diethanolamine, triethanolamine, n-ethylethanolamine, ethylenediamine, octylamine, benzylamine, tetraethanolammonium hydroxide, Quaternary ammonium hydroxide such as monomethyltriethanolammonium hydroxide, guanidine, etc.
The salts include hydrochloride, methyl sulfate, sulfate, etc. The amount of the organic base or its salt added is 0.5 to 20% by weight based on sodium antimonate,
If it is less than 0.5% by weight, the aggregation of the antimony pentoxide colloid cannot be suppressed, and if it is more than 20% by weight, the gel will significantly peptize during washing, making washing difficult. Also,
Reaction timeThe reaction can be selected arbitrarily, but from the viewpoint of productivity
10 hours is preferred.

Antimony pentoxide produced by the reaction of the present invention becomes aggregates of 1 μ or more, and is filtered by pressure filtration (suction filtration).
It can be easily separated by methods such as filter press filtration) and centrifugal filtration. Furthermore, coexisting acids, sodium ions, and organic bases can be easily removed by washing.

In the present invention, the alkali metal, alkaline earth metal hydroxide and/or salt are added by aging the antimony pentoxide gel dispersion obtained by the above reaction before drying at 50 to 100°C for 1 to 10 hours. , the antimony pentoxide structure must be strengthened. In the absence of ripening, the addition of alkali turns ammotine pentoxide into alkali metal salts and alkaline earth metal salts, making it impossible to maintain the ammotine pentoxide structure. Further, the alkali metal or alkaline earth metal hydroxide can be added in either an aqueous solution or a solid form while stirring.

In the present invention, the amount of alkali metal or alkaline earth metal hydroxide added varies depending on the remaining amount of sodium in the antimony pentoxide obtained by the reaction.
It is preferable that the total amount of the alkali metal and alkaline earth metal after addition is 0.4 to 0.8 in molar ratio relative to antimony pentoxide as _M2O and M'O, respectively. If the molar ratio is less than 0.4, the acidity of antimony pentoxide cannot be reduced;
A value of 0.8 or more is not preferable because it becomes alkaline.
Further, addition of alkali metal and alkaline earth metal hydroxides is possible at room temperature to 100°C, but at temperatures above 100°C, the gel may partially peptize and the filterability may be significantly reduced. The preferred addition temperature is room temperature to 60°C. Although the addition of the alkaline earth metal hydroxide and/or salt of the present invention does not change the filterability, and the addition of the alkali metal further reduces the size of the antimony pentoxide gel, the slurry The antimony pentoxide gel can be separated by methods such as suction filtration, filter press, and centrifugal filtration without significantly reducing the filterability of the antimony pentoxide gel. The resulting cake has a water content other than crystallization water of 20% or less and can be easily dried. Drying is possible from room temperature to 500°C, and those obtained by drying at temperatures below 270°C contain 4 to 16% crystal water, while those obtained by drying at temperatures above 270°C become anhydrous. For drying, use a hot air dryer,
A kiln dryer, a vacuum dryer, a spray dryer, etc. can be used.

In the present invention, salts of alkali metals and alkaline earth metals (chlorides, sulfates, nitrates, acetates, etc.) can be used, but after separating the gel, thorough washing is required. Metal hydroxides are preferred.

Antimony pentoxide gel produced according to the present invention
150℃ dry product is Sb ₂ O ₅ 70-86% by weight, M ₂ O + M′O
(M: alkali metal, M′: alkaline earth metal) 6
~20% by weight, water of crystallization; 4-16% by weight ( _M2O +
The molar ratio of M′O)/Sb ₂ O ₅ is between 0.4 and 0.8. or,
The water content of the dehydrated product dried at 300°C is 2% or less.

The dried antimony pentoxide gel of the present invention can be easily pulverized by a known method such as a high-speed rotary mixer, pin disc mill, jet oomizer, or ball mill. In particular, since fine powder of 0.5 to 5 μm can be obtained using a simple method such as a pin disc mill, the cost of grinding is significantly reduced. The dried antimony pentoxide gel obtained by reacting only with sodium antimonate and acid can only be powdered with an average particle size of 6 to 10 μm even if it is pulverized using a Jet Ohmizer or a pin disk mill under the same conditions. It can be seen from the above that the dry antimony pentoxide gel produced according to the present invention has very good crushability (see Comparative Example).

The antimony pentoxide flame retardant produced according to the present invention is a halogen-containing vinyl resin, which is a copolymer of vinyl chloride resin, ethylene, propylene, vinylidene chloride, vinyl alcohol, vinyl acetate, acrylic ester, etc., polyethylene, polypropylene, polyvinyl acetate. , thermosetting resins and thermoplastic elastomers such as halogen-free thermoplastic resins, such as polystyrene, polycarbonate, polyester alone or copolymers, epoxy resins, phenolic resins, melamine resins, unsaturated polyester resins, etc. Can be used on synthetic rubber.

In addition, for resins other than halogen-containing resins and synthetic rubber, hexabromobenzene, pentochlorophenol, decabromoxydiphenyl ether,
A good flame retardant effect can be obtained by using the antimony pentoxide flame retardant of the present invention in combination with an organic halogen compound such as tetrabromobisphenol A, chlorinated paraffin, or chlorinated polycarbonate.

Further, even when the antimony pentoxide flame retardant produced by the method of the present invention is added to the above synthetic resin, the main properties of the resin such as thermal stability and weather resistance are not impaired, and transparency and colorability are also good. Next, the present invention will be explained in more detail with reference to Examples. However, the present invention is not limited to the following examples. First, we will explain the manufacturing method of antimony pentoxide flame retardant.
Next, the flame retardant evaluation will be shown.

Example 1 Sodium antimonate (Sb ₂ O ₅ 65%, Na ₂ O
12.5%, H ₂ O 22.5%) was dispersed in 600 g of water,
To this was added 6 g of triethanolamine, and the reaction was carried out at 25° C. for 4 hours with stirring. The amine/sodium antimonate weight ratio is 3.4, and the hydrochloric acid/sodium antimonate stoichiometric ratio is 2.0.
After the reaction is complete, filter with a suction filter and collect 2000g of pure water.
Water injection cleaning was performed three times. The obtained wet cake was dispersed in 600 g of pure water, aged at 60°C for 2 hours, cooled to room temperature, and added with 20% potassium hydroxide aqueous solution.
After adding 50 g and stirring for 1 hour, the resulting cake was filtered under suction, dried at 300° C., and then ground in a pin disk mill. The obtained antimony pentoxide has an antimony pentoxide structure and contains 81% Sb ₂ O ₅ ,
Na ₂ O 3.8%, K ₂ O 6.5%, H ₂ O 1.6% (Na ₂ O +
The K ₂ O)/Sb ₂ O ₅ molar ratio was 0.49, and the average particle diameter was 2.5 μm.

Example 2 720 g of sodium antimonate was dispersed in 2000 g of water, and 50 g of diethanolamine was added thereto.
Next, 800 g of 35% aqueous hydrochloric acid solution was added, and the reaction was carried out at 30° C. for 3 hours with stirring. (Amino/sodium antimonate ratio 0.069, hydrochloric acid/sodium antimonate stoichiometric ratio 2.65) After the reaction, filter it with a centrifugal filter and use 9000 g of pure water to
Washed with water twice. The obtained wet cake was dispersed in 1500 g of pure water, heated at 80°C for 2 hours, cooled to room temperature, and barium hydroxide octahydrate (Ba
(OH) _{2.8H 2} O) was added with strong stirring, and stirring was continued for 2 hours. Subsequently, centrifugal filtration was performed, and the cake was dried at 180°C and then ground using a diet Ohmizer. This was heated to 320°C and dehydrated. The obtained antimony pentoxide has an antimony pentoxide structure and contains 81.7% Sb ₂ O ₅ and Na ₂ O 4.7
%, Ba12.6%, H ₂ O 1.0% (Na ₂ O + BaO) /
The Sb ₂ O ₅ molar ratio was 0.63 and the average particle size was 1.3 μm.

Example 3 720 g of sodium antimonate was dispersed in 1,600 g of water, and 120 g of a 30% monomethyltriethanolammonium hydroxide aqueous solution was added thereto.
Next, 500 g of a 60% aqueous nitric acid solution was added, and the reaction was carried out at 20° C. for 5 hours with stirring. (Amine/sodium antimonate ratio 0.05, hydrochloric acid/sodium antimonate stoichiometric ratio 1.64) After the reaction was completed, suction filtration was performed, and then water injection washing was performed three times using 1.2 kg of pure water. The obtained wet cake was dispersed in 2000 g of pure water, aged at 80°C for 5 hours, cooled to room temperature, and 93% sodium hydroxide (solid) was added.
37.5 g was added with vigorous stirring and stirring continued for 3 hours. Next, filter with a suction filter to obtain pure water.
Pour water once with 2000g and wash the resulting cake with 120g of water.
After drying at ℃, it was pulverized in a pindein mill. The obtained antimony pentoxide has an antimony pentoxide hydrate structure, containing 82.5% Sb ₂ O ₅ and 10.7% Na ₂ O.
%, _H2O 6.8%, _Na2O / _Sb2O5 molar _ratio 0.68, and average particle size 2μ.

Example 4 350 g of sodium antimonate was dispersed in 900 g of water, and 40 g of triethanolamine was added thereto.
Next, 600 g of a 40% nitric acid aqueous solution was added, and the reaction was carried out at 25° C. for 2 hours with stirring. (Amine/sodium antimonate ratio 0.114, nitric acid/sodium antimonate stoichiometric ratio 3.5) After the reaction was completed, suction filtration was performed, and then water injection washing was performed four times using 6000 g of pure water. Pour the obtained wet cake into pure water.
Dispersed in 1000g, aged at 90℃ for 3 hours, cooled to room temperature, and added 30g of 93% sodium hydroxide (solid).
was added with vigorous stirring and stirring continued for 3 hours. Subsequently, the cake was filtered using a suction filter, washed once with 2000 g of pure water, and the resulting cake was dried at 150° C. and then ground using a jet oomizer. This was heated at 300°C for 2 hours to dehydrate it. The obtained antimony pentoxide has an antimony pentoxide structure, and contains 86.6% Sb ₂ O ₅ , 12.2% Na _{2 O} , 1.2% H _{2 O} ,
The Na ₂ O/Sb ₂ O ₅ molar ratio was 0.73 and the average particle size was 0.8 μ.

Comparative Example 1 175g of sodium antimonate was dispersed in 600g of water, 6g of triethanolamine was added thereto,
80 g of 35% aqueous hydrochloric acid solution was added, and the reaction was carried out at 25° C. for 3 hours. (amine/sodium antimonate
0.034, stoichiometric ratio of hydrochloric acid/sodium antimonate 1.1) After the reaction was completed, it was filtered with a suction filter, and then washed with water three times using 1.5 kg of pure water.
The obtained wet cake was dried at 120°C and then pulverized in a pindein mill. This was heated to 300°C to dehydrate it. The obtained antimony pentoxide has an antimony pentoxide structure and contains 94.9% Sb ₂ O ₅ ,
Na ₂ O 3.2%, H ₂ O 1.9%, Na ₂ O/Sb ₂ O ₅ molar ratio
0.18, and the average particle diameter was 8μ.

Comparative Example 2 720g of sodium antimonate was dispersed in 1500g of water, 61g of 35% hydrochloric acid was added thereto, and the mixture was mixed with stirring.
The reaction was carried out at 20°C for 2 hours. (Hydrochloric acid/sodium antimonate stoichiometric ratio 2.0) After the reaction is complete, filter with a centrifugal filter, and then use 6000 g of pure water to
Washed with water twice. The obtained wet cake was dispersed in 1500 g of pure water, 35 g of 93% sodium hydroxide (solid) was added thereto with strong stirring, and stirring was continued for 3 hours. Subsequently, it was filtered using a centrifugal filter, and the cake was dried at 310°C and then ground using a pin deinsc mill. The obtained antimony pentoxide has an antimony pentoxide structure and contains 88.6% Sb ₂ O ₅ ,
Na ₂ O 9.7%, H ₂ O 1.7%, Na ₂ O/Sb ₂ O ₅ molar ratio
0.58, and the average particle diameter was 7μ.

Comparative Example 3 175 g of sodium antimonate was dispersed in 600 g of water, and 40 g of a 35% aqueous hydrochloric acid solution was added thereto, followed by reaction at 25° C. for 6 hours with stirring. (Hydrochloric acid/sodium antimonate stoichiometric ratio: 0.55) After the reaction was completed, the mixture was filtered by suction filtration, and then washed three times with 1200 g of pure water. The obtained wet cake was dried at 150°C and then pulverized in a pindein mill. As a result of X-ray diffraction, the product is a mixture of antimony pentoxide hydrate and sodium antimonate hydrate, with _73.8 % _Sb2O5 , _8.2 % Na2O,
H ₂ O 18%, Na ₂ O/Sb ₂ O ₅ molar ratio 0.58, and average particle size 8.5 μ.

[Evaluation of flame retardancy]

As shown in Table 1, the examples were added to 100 parts by weight of the synthetic resin.
and antimony pentoxide flame retardant produced in comparative example,
Organic halogen compounds, blue pigments, etc. are mixed thoroughly in a high-speed rotating mixer, and then injection molded.
A test piece with a thickness of 3.2 mm was prepared, and the main physical properties, flame retardancy, transparency, and colorability of the obtained flame-retardant resin composition were measured. In addition, for vinyl chloride, press molding was performed after hot roll kneading, and similar measurements were performed. The results are shown in Table 1.

Flame retardancy: Measured according to US UL Standard No. 94. 94-V-0, 94-V-1 94 from those with good flame retardancy
-V-2, 94-HB.

Transparency: Shown as transmittance (%).

Blueness: The quality of blue color, which is good for visual perception, was judged.

Main physical properties: thermal stability, weather resistance, tensile strength, and impact resistance were measured.

[Brief explanation of drawings]

Figure 1 is an X-ray diffraction diagram of the product obtained in Comparative Example 3, Figure 2 is an X-ray diffraction diagram of the product obtained in Example 1, and Figure 3 is an X-ray diffraction diagram of the product obtained in Example 3. FIG.

【table】

【table】

Claims (1)

[Claims] 1 The alkali metal is M ₂ O (M is an alkali metal), the alkaline earth metal M'O (M' is an alkaline earth metal), each singly or in combination, antimony pentoxide (Sb ₂ O ₅ ), an antimony pentoxide flame retardant containing 0.4 to 0.8 in molar ratio and having an antimony pentoxide structure. 2. In a method for obtaining a flame retardant from sodium antimonate and an inorganic acid, (a) dispersing sodium antimonate in water, adding 0.5 to 20% by weight of an organic base or its salt to the sodium antimonate, 1.5 to 5 stoichiometric amounts of sodium antimonate
(b) This gel is filtered, washed with water, and dispersed in water for 50 to
(c) This is then treated with an alkali metal hydroxide and/or
Alternatively, it consists of steps (a) to (c) of adding salt, alkaline earth metal hydroxide and/or salt, each singly or in combination, and drying and pulverizing this after filtration. _M2O (M
is an alkali metal), and an alkaline earth metal is
It is characterized by containing M'O (M' is an alkaline earth metal), either alone or in combination, in a molar ratio of 0.4 to 0.8 to antimony pentoxide (Sb ₂ O ₅ ), and having an antimony pentoxide structure. A method for producing antimony pentoxide flame retardant.