JPH0813967B2 - Antimony trioxide dispersion for flame retardant and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antimony pentoxide-coated antimony trioxide dispersion for flame retardants and a method for producing the same. More specifically, a mixture of acidic antimony pentoxide sol and antimony trioxide powder is reacted and reacted, and the antimony trioxide particle surface is coated with colloidal particles of antimony pentoxide. The present invention relates to an antimony dispersion liquid and a method for producing the same. The main use of the antimony trioxide dispersion is as a flame retardant for fibers, resin products, etc., as in conventional antimony oxide.

(Prior Art) Antimony oxides used as flame retardants include antimony trioxide and antimony pentoxide.

Since antimony trioxide shows excellent flame retardance by reacting with halogen, halogen-containing resin and polyethylene, polycarbonate, polyester, ABS can be used by combining antimony trioxide alone or with a halogen-based flame retardant or a phosphorus-based flame retardant. It is widely used as a flame retardant for halogen-free resins such as resins.

In recent years, with the remarkable progress of electricity, electronics industry, automobile industry, aircraft industry, housing industry, etc., there has been a strong demand for flame retardant fiber and plastic products from the viewpoint of disaster prevention.
Expectations for antimony flame retardants are also increasing.

Although antimony trioxide has been used mainly as a powder mixed with a resin, it may be used as a dispersion of antimony trioxide by dispersing antimony trioxide in water or an organic solvent. An example of the use of the dispersion of antimony trioxide is a backing treatment for flame-retarding a woven, knitted or non-woven fabric made of natural or synthetic fibers such as wool, rayon, polyester and polypropylene. This treatment agent is called flame retardant compound, resin emulsion and antimony trioxide, dispersant, defoamer,
Consists of thickeners, organic halogen compounds, calcium carbonate, aluminum hydroxide, etc.

In the antimony trioxide dispersion, almost no antimony trioxide is used in a dispersed state. this is,
This is because antimony trioxide has poor wettability with water and thus is difficult to disperse in water, and particularly because the equipotential point is in the neutral region, it is difficult to disperse in the neutral region. Therefore, antimony trioxide is dispersed using a considerably large amount of dispersant and surfactant. However, even with this method, antimony trioxide cannot be dispersed to the size of the primary particles, and the particles agglomerate in the liquid and become large, so that they easily settle.
For this reason, there is a problem that the amount of the thickener required to prevent sedimentation increases, the viscosity of the dispersion liquid increases, and handling becomes difficult.

Further, the presence of a large amount of the surfactant may impair the stability of the resin emulsion when mixed with the resin emulsion.

On the other hand, since antimony pentoxide can be used as an antimony pentoxide sol, it is used as a flame retardant utilizing the characteristics of the sol. (JP-B-59-47717, JP-A-60-259678) Antimony pentoxide sol has excellent dispersibility and does not thicken even in the neutral range, so it is easy to use, and in combination with a halogen emulsion, good flame retardancy. Shows sex. However, the combination of a halogen-free resin emulsion such as an acrylic emulsion and an organic bromine compound has a drawback that it is difficult to obtain sufficient flame retardancy.

As mentioned above, antimony trioxide is used for flame retarding resin molded products and fibers, but antimony trioxide has a high refractive index and a large particle size, which reduces the transparency of the resin and coloring with a pigment. It has a drawback that it deteriorates the property.
Furthermore, when resin molded articles and fibers flame-retarded with antimony trioxide are used in an atmosphere of a sulfur-containing compound such as hydrogen sulfide, sulfides of antimony trioxide are produced, and the product becomes yellow. Have Further, when plating is performed on a printed circuit board flame-retarded with antimony trioxide, there is a drawback that antimony trioxide elutes in the plating solution and deteriorates the plating characteristics. Further, antimony trioxide has a drawback that resin such as polyester causes depolymerization during molding.

JP-B-54-25949 proposes a method of improving the chemical resistance of antimony trioxide by coating the surface of antimony trioxide particles with hydrous zirconium oxide and amorphous silica. However, since silica does not exhibit flame retardance, antimony trioxide produced by this method has low flame retardancy.Since the bond between antimony trioxide and hydrous zirconium oxide and amorphous silica is weak, the dispersion machine and molding It has a drawback that the coated hydrous zirconium oxide and the amorphous silica are separated when mechanical shearing force is applied by a machine.

The inventors of the present invention have proposed in JP-A-60-108466 a method of treating antimony trioxide with hydrogen peroxide and then subjecting it to alkali treatment to improve the sulfidation resistance of antimony trioxide. . However, in this method, not only the surface is oxidized but also antimony pentoxide is considerably produced, so that the chemical resistance is improved, but the production of antimony pentoxide causes a slight decrease in flame retardancy.

(Problems to be Solved by the Invention) The inventors of the present invention have the problems that the above-mentioned antimony trioxide dispersion liquid has a high viscosity and is difficult to handle, and that the antimony trioxide flame retardant has sulfide resistance and plating characteristics. In addition, a diligent study was made to solve the problems of lowering the flame retardancy, and that it is difficult to obtain sufficient flame retardancy with a combination of a halogen-free resin emulsion such as an acrylic emulsion of antimony pentoxide sol and an organic bromine compound. The present invention has been completed. That is, an object of the present invention is to provide an antimony trioxide dispersion liquid that has excellent flame retardancy and sulfide resistance, is stable, and has a low viscosity, and is easy to handle as an antimony trioxide flame retardant.

(Means for Solving Problems) The present inventors can achieve the object of the present invention by coating the surface of antimony trioxide particles with a colloid of antimony pentoxide. It has been found that a dispersion of antimony can be obtained.

That is, the first invention of the present invention is a flame-retardant solution of antimony trioxide dispersed in water as a dispersion medium, the particle surface of the dispersed antimony trioxide is coated with colloidal particles of antimony pentoxide, if necessary. The present invention relates to an antimony trioxide dispersion for flame retardants, characterized in that the pH of the dispersion is 7 to 10 with a basic substance.

The second invention of the present invention also relates to a method for producing the antimony trioxide dispersion for a flame retardant of the first invention. The manufacturing method is
An acidic antimony pentoxide aqueous sol and antimony trioxide powder are mixed and reacted to obtain a dispersion of antimony trioxide in which the surface of antimony trioxide particles is coated with a colloid of antimony pentoxide, and if necessary, a basic substance PH by adding
Is set to 7 to 10.

The present invention will be described in detail below. As the acidic antimony pentoxide sol used in the present invention, an acidic antimony pentoxide sol having a primary particle diameter of 5 to 100 mμ obtained by a conventionally known method can be used. Water and organic solvents are known as dispersion media for antimony pentoxide sol, but the antimony pentoxide sol used in the present invention must be an aqueous sol and acidic. A neutral to alkaline antimony pentoxide sol made with amine, ammonia, sodium hydroxide or the like is not preferable because the surface of the antimony pentoxide colloidal particles is covered with a basic substance, so that the binding property with antimony trioxide decreases.

Conventionally known methods for producing antimony pentoxide sols include a method of oxidizing antimony trioxide sol with hydrogen peroxide (Japanese Patent Publication No. 57-11848) and a method of dealkalizing alkali antimonate with an ion exchange resin (US Patent 4110247
No.), a method of deflocculating an antimony pentoxide gel obtained by reacting an alkali antimonate with an inorganic acid with amine or phosphoric acid (JP-A-60-41536 and JP-A-61-227918). The antimony pentoxide sol obtained by any of these methods can be used in the present invention.

The colloid of antimony pentoxide in this antimony pentoxide sol is basically Sb ₂ O ₅ .4H ₂ O, and contains sodium depending on the production method. Antimony pentoxide is an inorganic ion exchanger, especially sodium ions are incorporated into the structure of antimony pentoxide. When the acidic antimony pentoxide sol used in the present invention contains sodium, it can be expressed as Sb ₂ O ₅ (Na ₂ O) _x · 4H ₂ O in the form of X.
= 0.6 or less is an acidic sol.

The concentration of antimony pentoxide in the antimony pentoxide sol which can be used in the present invention is ₅ to 55% by weight as Sb ₂ O ₅ . If the Sb ₂ O ₅ concentration is less than 5%, the concentration of the obtained dispersion liquid becomes low, which is not preferable.

As the antimony trioxide used in the present invention, antimony trioxide powder produced by any method such as one produced from antimony oxychloride or one produced by burning metal antimony or antimony sulfide can be used in the present invention. It can also be applied to colloidal antimony trioxide having a particle size of 0.1 μm or less, which is obtained by the method described in Japanese Patent Publication No. 45-14385. The particle size of ordinary antimony trioxide powder is generally 0.4 to 10 μm.

The method for producing an antimony trioxide dispersion for a flame retardant of the present invention is a method in which the above-mentioned acidic antimony pentaoxide sol and the above antimony trioxide powder are mixed and reacted, and a colloid of antimony pentaoxide is formed on the surface of antimony trioxide particles. By the method of coating the particles. The reaction temperature may be 100 ° C. or higher, preferably room temperature to 100 ° C., particularly preferably 40 to 100 ° C.
° C. The reaction time may be shorter as the treatment temperature is higher, but it is 1 to 30 hours. The acid antimony pentoxide sol and the antimony trioxide are mixed so that the weight ratio of Sb ₂ O ₅ / Sb ₂ O ₃ is at least 5% by weight or more, preferably 7 to 50% by weight, more preferably 7 to 30% by weight. Mix so that This mixed amount is determined by the particle size and surface area of antimony trioxide and antimony pentoxide. As mentioned above, antimony trioxide is generally 0.4-10 μm, and its surface area is 0.1-
3m ² / g, antimony pentoxide colloidal particles have a particle size of 5 to 100mμ and a surface area of 15 to 300m ² / g
Is. Therefore, if the weight ratio of Sb ₂ O ₅ / Sb ₂ O ₃ is less than 5% by weight, the surface of antimony trioxide particles cannot be sufficiently covered, and if it exceeds 30% by weight, antimony pentoxide can be used. Since the amount of colloid is excessive, the effect of coating cannot be further increased. In this case, it is a mixed dispersion liquid of antimony trioxide and antimony pentoxide coated with antimony pentoxide. Excessive antimony pentoxide may be present as long as the dispersion is stable, but if the amount of excess antimony pentoxide increases, the cost will increase and the drawbacks of antimony pentoxide will appear. The amount of antimony is preferably within 50% by weight based on the weight ratio of Sb ₂ O ₅ / Sb ₂ O ₃ .

The antimony pentoxide sol and the antimony trioxide are preferably mixed with a disperser, a homogenizer, a ball mill, a sand glider or the like, and a disperser or a homogenizer having a strong dispersive power is particularly preferable.

The dispersion liquid of antimony trioxide thus obtained is in the form of slurry. Antimony oxide concentration (Sb
The total amount of ₂ O ₃ and Sb ₂ O ₅ ) is 80% by weight or less, preferably 20 to 70% by weight. If the concentration of antimony oxide exceeds 80% by weight, the viscosity of the dispersion becomes too high and mixing cannot be performed sufficiently. Further, if the concentration of antimony oxide is less than 20% by weight, the amount of the dispersion liquid required at the time of use is not preferable.

By this treatment, antimony pentoxide reacts as an oxidant, and oxygen is transferred between the surfaces of antimony trioxide and antimony pentoxide to produce antimony tetroxide, and the antimony pentoxide colloidal particles are strongly bound to the surface of the antimony trioxide particles. Cover in the condition

The dispersion liquid of antimony trioxide obtained by the above method is
It has a pH of 2 to 6, has low viscosity and is stable, and can be used as a dispersion for a flame retardant. However, the treatment liquid used by mixing the antimony trioxide dispersion liquid with the resin emulsion is often used from weakly acidic to alkaline, so that, if necessary, the antimony trioxide dispersion liquid may be added to the antimony trioxide dispersion liquid obtained by the above method. It is preferable to adjust the pH by adding a basic substance.

To adjust the pH, a basic substance is added to the antimony trioxide dispersion to adjust the pH to 7-10. The addition method at this time is preferably the same as that when the antimony trioxide powder is added to the antimony pentoxide sol. The antimony trioxide dispersion of the present invention does not deteriorate the properties of the dispersion even if the pH is adjusted to 7 to 10 with a basic substance, but rather becomes a more stable dispersion.

Examples of the basic substance that can be used include alkali metal or alkaline earth metal hydroxides, amines, ammonia, quaternary ammonium hydroxide aqueous solutions, guanidine hydroxide aqueous solutions, and the like. Among these, the amine is preferably alkanolamine such as monoethanolamine, diethanolamine and triethanolamine, and the hydroxide is preferably sodium hydroxide, barium hydroxide or ammonia. You may use combining these bases. For example, Sb ₂ O ₅
On the other hand, a method of adding sodium hydroxide as Na ₂ O in an amount of 0.3 to 0.6 mol and further adding an amine and / or ammonia is preferable.

Although the dispersion liquid of antimony trioxide obtained in the present invention is stable as it is, a dispersant, a defoaming agent, a thickening agent (anti-settling agent) and the like may be added if necessary. Especially when long-term storage stability is required, it is preferable to add a thickener.

The dispersion liquid of antimony trioxide obtained by the present invention is stable even when mixed with a resin emulsion, and can be used in a well dispersed state. As the resin emulsion, vinyl chloride emulsion, vinylidene chloride emulsion, or halogen-containing resin emulsion which is a copolymer of vinyl chloride resin and ethylene, propylene, vinylidene chloride, vinyl alcohol, vinyl acetate, acrylic ester, etc., and vinyl acetate emulsion , Acrylic emulsion, acrylic styrene emulsion, urethane emulsion and the like can be used.

When the antimony trioxide dispersion of the present invention is used in the above-mentioned halogen-free emulsion, organic halogen such as hexabromobenzene, pentachlorophenol, decabromoxoxydiphenyl ether, tetrabromobisphenol A, chlorinated paraffin and chlorinated polycarbonate. A good flame retardant effect can be obtained by using the compound in combination.

Furthermore, the antimony trioxide dispersion of the present invention can be used as a mixture with anionic and nonionic surfactants, silicone water repellents, polyvinyl alcohol, hydroxyethyl cellulose, CMC, polysaccharides, sodium polyacrylate,
It can also be used as a mixture with a thickener such as sodium alginate and bentonite. Further, inorganic fillers such as calcium carbonate, kaolin, talc, silica, aluminum hydroxide and titanium oxide, pigments and the like can be added.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.
In addition,% means% by weight unless otherwise specified.

Example 1 Antimony pentoxide sol having a particle size of 10 to 40 mμ (surface area 7
_{^{2m 2 / g, Sb 2 O}} 5 13%, Na 2 O0.75%, Na 2 O / Sb 2 O 5 molar ratio of 0.
3, pH 2.2) 1020g antimony trioxide (Suzu Yu Chemical Co., Ltd.
1340 g of particle size 1-2 μ surface area 0.7 m ² / g) was added and stirred with a disper for 1 hour.

The pH of this slurry was 2.2 and the viscosity was about 2000 c.p. The slurry was heated to 80 ° C. and kept for 2 hours while stirring. The viscosity of the obtained antimony trioxide dispersion was 17
The pH was 2.5 at 5 c.p. The antimony oxide concentration (Sb ₂ O ₃ + Sb ₂ O ₅ ) of this antimony trioxide dispersion was 62.1%, Sb ₂ O
_{3 56.5%, Sb 2 O 5} 5.6%, by weight of Sb ₂ O ₃ and Sb ₂ O ₅ is Sb ₂ O ₅ / S
b ₂ O ₃ is 9.9%. 28 in this antimony trioxide dispersion
The pH was adjusted to 10.0 by adding 10.5 g of% ammonia water. The resulting dispersion had a viscosity of 125 c.p. and had a tendency to separate by standing, but the redispersibility was very good. The particle size of antimony trioxide in this dispersion was 1.7 μm.

Example 2 1020 g of the same antimony pentoxide sol as in Example 1 was added with an antimony pentoxide sol having a particle size of 20 to 50 μm (surface area 63 m ² / g, S
b ₂ O ₅ 48.5%, Na ₂ O 3.16%, Na ₂ O / Sb ₂ O ₅ molar ratio 0.34, triethanolamine 2.0%, pH 5.4 (200 g) was added, and then antimony trioxide (Sumitomo Metal Mining Co., Ltd. Company, particle size 0.7
1600 g (μ, surface area 1.6 m ² / g) was added with stirring with a disper, and after stirring at room temperature for 1 hour, the liquid temperature was raised to 70 ° C. and further stirring for 2 hours. The pH of the resulting dispersion was 3.0. To this, add 58 g of 20% caustic soda solution, and add 28
20 g of% aqueous ammonia was added. The pH of the resulting dispersion is
At 8.0, the viscosity was 150 c.p. The dispersibility was good.

Thickener (trade name Kerzan) was added to this dispersion,
Those whose viscosity was increased to 2000 c.p. had very good storage stability, and no sedimentation was observed even after standing for 3 months.

The weight ratio of Sb ₂ O ₃ and Sb ₂ O ₅ in this dispersion is Sb ₂ O ₅ / Sb ₂ O ₃ which is 1
5.8%, and the concentration of antimony oxide (Sb ₂ O ₃ + Sb ₂ O ₅ ) is 6
It was 0%. The Na ₂ O / Sb ₂ O ₅ molar ratio was 0.5.
The particle size of antimony trioxide in this antimony trioxide dispersion was 1.0 μm.

Example 3 To 200 g of antimony pentoxide sol having a particle size of 20 to 50 mμ used in Example 2, 90 g of water was added, and then antimony trioxide (Suzuhiro Chemical Co., Ltd. particle size of 1 to ² μ surface area 0.7 m ² / g) 350
g was added with stirring with a disper, the temperature was raised to 50 ° C., and the mixture was further stirred for 6 hours. The pH of the resulting dispersion is 5.
It was 9. 2 g of triethanolamine was added to this dispersion to adjust the pH to 9.2. The obtained antimony trioxide dispersion had a viscosity of 480 c.p. and good stability.

The weight ratio of Sb ₂ O ₃ and Sb ₂ O ₅ in this dispersion is Sb ₂ O ₅ / Sb ₂ O ₃
27.7%, and the concentration of antimony oxide (Sb ₂ O ₃ + Sb ₂ O ₅ )
Was 70.2%. The diameter of the antimony trioxide particles in this antimony trioxide dispersion was 1.7 μm. Although it showed a tendency to separate when allowed to stand, redispersibility was very good.

Example 4 Example 2 was applied to 435 g of the same antimony pentoxide sol as Example 1.
Antimony pentoxide sol with a particle size of 20-50mμ used in 1
00g was added, and then 575g of antimony trioxide (manufactured by Mikuni Smelting Co., Ltd., particle size 0.36μ, surface area 3.2m ² / g) was added while stirring with a disper, and the liquid temperature was 75 after stirring at room temperature for 1.5 hours. The temperature was raised to ° C and the mixture was further stirred for 3 hours. The resulting dispersion had a pH of 3.95 and a viscosity of 600 c.p. It was very stable with little separation by standing.

The weight ratio of Sb ₂ O ₃ and Sb ₂ O ₅ in this slurry was Sb ₂ O ₅ / Sb ₂ O ₃
Is 18.3%, and antimony oxide concentration (Sb ₂ O ₃ + Sb ₂ O ₅ )
Was 61.3%. The Na ₂ O / Sb ₂ O ₅ molar ratio was 0.32. The diameter of the antimony trioxide particles in this antimony trioxide dispersion was 0.7μ.

Comparative Example 1 To 1630 g of water, 2400 g of antimony trioxide (particle size: 1-2 μ, surface area: 0.7 m ² / g, manufactured by Suzu Yu Chemical Co., Ltd.) was added, and the mixture was mixed with a disper.
Stirred for hours. The resulting dispersion has a pH of 5.3 and a viscosity of 5200 c.p.
Met. The concentration of antimony trioxide in this dispersion was 59.3.
%Met. Ammonia water (10 g) was added to this dispersion to adjust the pH to 1
Although it was set to 0.4, the viscosity was 3200 c.p. and the fluidity was low and the handling was extremely poor. The particle size of antimony trioxide in this dispersion was 4.2 μm and the dispersibility was very poor.

Comparative Example 2 Alkaline antimony pentoxide sol (Sb ₂ O ₅ 48.3%, N
a ₂ O 6.1%, triethanolamine 2.5%, particle size 20-30m
μ, surface area 60 m ² / g, pH 8.0) 200 g, and the same antimony trioxide 320 g as in Comparative Example 1 were added, and the mixture was stirred with a disper at 50 ° C. for 2 hours. The obtained dispersion had a pH of 7.8, an antimony oxide concentration of 72.8%, a viscosity of 1650 c.p. and a relatively good dispersion, but the antimony pentoxide colloid was weakly adsorbed on the surface of antimony trioxide. However, the antimony trioxide settles and solidifies upon standing, and redispersibility is very difficult.

[Evaluation of flame retardants]

Antimony trioxide dispersions of Examples 1 to 4 and Comparative Example 1 and vinylidene chloride emulsion (Kureha Chemical Co., Ltd., Kurehalon VAT312), or acrylic emulsion (Towa Gosei Co., Ltd., Boncoat 350), decabromoxy as a bromine flame retardant. Diphenyl ether was mixed in the composition as shown in Tables 1 and 2, and the stability of the obtained liquid, the oxygen index of the sheet obtained by drying the liquid, and the weather resistance were measured. The blending amount is parts by weight. The evaluation results of the flame retardant are shown in Tables 1 and 2. As shown in the table, the antimony trioxide dispersion of the present invention has good stability when mixed with a resin emulsion, and has excellent flame retardancy and weather resistance.

Claims (6)

[Claims] 1. A dispersion of antimony trioxide for a flame retardant containing water as a dispersion medium, the surface of dispersed particles of antimony trioxide being coated with colloidal particles of antimony pentoxide,
A dispersion of antimony trioxide for a flame retardant, wherein the pH of the dispersion is adjusted to 7 to 10 with a basic substance, if necessary. 2. The total amount of antimony trioxide and antimony pentoxide dispersed is 20 to 80% by weight in the dispersion liquid, and the particle surface of antimony trioxide is at least 5% by weight based on antimony trioxide. The antimony trioxide dispersion for a flame retardant according to claim 1, which is antimony trioxide coated with colloidal particles of antimony pentoxide. 3. The antimony trioxide particles, wherein the dispersed antimony trioxide particle surfaces are coated with 7 to 30% by weight of antimony trioxide colloidal particles of antimony pentoxide. Antimony trioxide dispersion for flame retardants. 4. An antimony pentoxide aqueous sol and an antimony trioxide powder are mixed and reacted to obtain a dispersion of antimony trioxide in which the surface of the antimony trioxide particles is coated with colloidal particles of antimony pentoxide, which is required. A method for producing an antimony trioxide dispersion for a flame retardant, which comprises adding a basic substance to adjust the pH to 7 to 10 according to the above. 5. The total amount of dispersed antimony trioxide and antimony pentoxide is 20 to 80% by weight, and the amount of antimony pentoxide is at least 5% by weight based on antimony trioxide. 4. A method for producing an antimony trioxide dispersion for a flame retardant according to item 4. 6. The method for producing an antimony trioxide dispersion for a flame retardant according to claim 5, wherein the amount of antimony pentoxide is 7% by weight to 50% by weight based on antimony trioxide.