Positively Charged Antimony Pentoxide Sol and Preparation Thereof

Home , Antimony pentoxide

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EUROPEAN PATENT SPECIFICATION

@ Date of filing: 03.04.86

® Priority: 03.04.85 JP 70720/85 Qj) Proprietor: NISSAN CHEMICAL INDUSTRIES LTD. @ Date of publication of application: 3-7-1, Kanda Nlshlkl-cho 15.10.86 Bulletin 86/42 Chlyoda-ku Tokyo(JP)

© Publication of the grant of the patent: @ Inventor: Watanabe, Yoshltane 15.07.92 Bulletin 92/29 Juneshlon Hlral No. 911 3-5-1, Hlral Edogawa-ku Tokyo(JP) © Designated Contracting States: Inventor: Teranlshl, Masayukl DE FR GB IT 7-27-13, Takanedal Funabashl-shl Chlba-ken(JP) © References cited: Inventor: Suzuki, Keltaro DE-A- 2 931 523 1-5-16-201, Narashlno US-A- 4 075 032 Funabashl-shl Chlba-ken(JP) US-A- 4 100 076 US-A- 4 100 077 US-A- 4 341 655 © Representative: Lehn, Werner, Dipl.-lng. et al Hoffmann, Eltle & Partner Patentanwalte Ar- abellastrasse 4 W-8000 Munchen 81 (DE)

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O Note: Within nine months from the publication of the mention of the grant of the European patent, any person ^ may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition qj shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid (Art. 99(1) European patent convention). Rank Xerox (UK) Business Services 1 EP 0 197 503 B1 2

Description use, because agglomeration occurs when it is mixed with a cationic water-soluble polymer. BACKGROUND OF THE INVENTION Further, for example, the antimony pentoxide sol finds its use in a flame retardant acrylic fiber. This invention relates to a positively charged 5 By introducing antimony pentoxide colloidal par- antimony pentoxide sol obtained by mixing an an- ticles into an acrylic fiber, there can be obtained a timony pentoxide sol with an aqueous solution of a flame retardant fiber having high transparency and basic salt of trivalent and/or tetravalent metal and excellent dyeability, and for this purpose antimony also to a process for producing the same. pentoxide sol must be dispersed without agglomer- Antimony pentoxide sols which have been io ation in a spinning solution of an acrylic fiber. known in the art are negatively charged on the Whereas, the antimony pentoxide sol of the prior surface of their particles. As the processes for art is liable to be agglomerated in an inorganic acid producing such sols, there have been known the such as sulfuric acid, nitric acid, etc., and a cone, method in which an alkali antimonate is deionized aqueous solution of an inorganic salt such as zinc with an ion-exchange resin (U.S. Patents Nos. 75 chloride, sodium rhodanide, which is a good sol- 3,860,523 and 4,110,247); the method in which vent for an acrylic polymer, whereby there are antimony trioxide is oxidized with hydrogen perox- involved the drawbacks such that clogging of noz- ide under a high temperature (U.S. Patent No. zle or fiber breaking may occur during spinning or 4,022,710, Japanese Unexamined Patent Publica- that transparency of the fiber obtained is markedly tion No. 21298/1977, U.S. Patent No. 4,026,819); 20 lowered. For this reason, in practical application, it the method in which an alkyl antimonate is allowed is required to perform a special operation such as to react with an inorganic acid, followed by pep- vigorous stirring during mixing (Japanese Unex- tization (Japanese Unexamined Patent Publication amined Patent Publication No. 142715/1980). No. 41536/1985). Further, for example, in the case of adding The above antimony pentoxide sols of the prior 25 antimony pentoxide sol as the microfiller for the art have been utilized for various uses by making purpose of flame retardancy and increase of sur- avail of their microparticulate characteristics. For face hardness into an alcoholic solution and water- example, they can be used as flame retardant alcoholic solution of a silicone resin to be used as treating agents or flame retardant adhesives for the surface treating agent for plastic moldings or fabrics by mixing with various resin emulsions. In 30 plastic films, the antimony pentoxide sol of the order for the mixture of the sol and a resin emul- prior art is susceptible to agglomeration, thereby sion to exhibit satisfactory flame retardant effect, having the drawback of being lowered in transpar- the particles of the antimony pentoxide sol are ency. required to be dispersed in the state approximate to primary particles without agglomeration as far as 35 SUMMARY OF THE INVENTION possible. Since the surface of the particles of the antimony pentoxide sol of the prior art is negatively An object of the present invention is to provide charged, it can be mixed with an anionic resin an antimony pentoxide sol which can be well dis- emulsion comprising particles with the same nega- persed in a cationic resin emulsion, a cationic tive surface charges without causing agglomeration 40 water-soluble polymer solution, inorganic and or- due to repellency of charges between the particles. ganic acid, aqueous solutions containing the metal Whereas, when a cationic resin emulsion compris- salts or organic amine salts of these acids, and ing particles with positive surface charges is mixed organic solvents such as alcohols, in which an- with an antimony pentoxide sol, agglomeration will timony pentoxide sols of the prior art could be instantly occur due to the mutually opposite polar- 45 dispersed with difficulty as described above. ity in charges, whereby no such mixture can be The present inventors have studied intensively practically used. on modification of the antimony pentoxide sol suit- On the other hand, an aqueous solution of a ed for the above object and consequently found water-soluble polymer has properties such as dis- that the desired antimony pentoxide sol can be persing, thickening, bonding, blocking properties, 50 obtained by coating the surfaces of the particles of and therefore used for surface treatment of plas- antimony pentoxide sol with at least one of trivalent tics, and the like. The water-soluble polymer in- and tetravalent metals. cludes polyvinyl alcohol, polyacrylamide, polyal- More specifically, the present invention con- kylene oxide and anionic or cationic polyelec- cerns a positively charged antimony pentoxide sol, trolytes such as polymers having carboxy groups, 55 comprising colloidal particles of antimony pentox- amino groups in side chains or main chains. How- ide coated on their surfaces with at least one of ever, the antimony pentoxide sol involve the trivalent and tetravalent metals, the content of said drawback that it cannot be provided for practical metal being 1 to 50 % by weight as the metal

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oxide based on antimony pentoxide (Sb2 05) and a AI(OH)(HCOO)2, basic zirconium chloride such as process for producing the same. Zr(OH)2Cl2, basic zirconium acetate such as Zr- (OH)2(CH3COO)2, basic zirconium nitrate such as DESCRIPTION OF THE PREFERRED EMBODI- Zr(OH)2(N03)2, basic titanium chloride such as Ti- MENTS 5 (OH)Cl3, basic titanium acetate such as Ti(OH)- (CH3C02)3, and the like. These compounds are In this invention, the expression "surfaces of available as powder or aqueous solutions and are the antimony pentoxide colloidal particles are coat- commercially available. ed with the above metal" means that said metal is The particles of antimony pentoxide sols are fixed onto the surfaces of the antimony pentoxide io not only negatively charged on the surfaces but colloidal particles under the state of polycations of also have strong ion-exchange capacity. Accord- said metal or microcolloide of said metal oxides or ingly, when antimony pentoxide sol is mixed with hydroxides. The concentration of antimony pentox- an aqueous solution of a basic salt, the surfaces of ide (sb2 05) in the antimony pentoxide sol positively the colloidal particles of antimony pentoxide sol are charged is within the range of from 1 to 60 % by is coated with the polycations (metal ions) in the weight, while the content of the trivalent and/or basic salt by fixing them not only through physical tetravalent metal is 1 to 50 % by weight as metal adsorption but also by chemical adsorption. For oxides based on Sb2 05. The average particle size this reason, a very stable colloid solution is formed of the colloid coated with said metal should be without heating or pressurization. At the moment of preferably be 5 to 150 mu.. The pH value of said 20 mixing of them, formation of primarily minute gels sol should preferably be 7 or less. will frequently occur and therefore it is preferable The process for producing the positively to perform strong stirring by means of a high charged antimony pentoxide sol of the present speed impeller mixer or a homoginizer. Also, by invention comprises mixing an antimony pentoxide employment of the method in which antimony pen- sol of pH 1 to 10 containing 5 to 60 % by weight of 25 toxide sol is added into an aqueous solution of a Sb2 05 and an aqueous solution of at least one of basic salt, formation of minute gels will be reduced, basic salts of trivalent and tetravalent metals at whereby the stirring time for obtaining a homo- proportions such that the amount of said basic salt geneous colloidal solution can be shortened. The may be 1 to 50 % by weight as the metal oxide amount of the basic salt added is preferably 1 to based on Sb2 05. 30 50 % by weight, preferably 3 to 20 % by weight in The antimony pentoxide sol to be used in the terms of the oxide of the metal constituting the present invention may include antimony pentoxide basic salt (M2O3 or MO2) based on Sb2 05 in the sols obtained by various preparation methods antimony pentoxide sol. The necessary amount of known in the art as mentioned above. Of these the basic salt added depends on the specific sur- sols, sols with any pH may be available, such as 35 face area of the antimony pentoxide sol particles. the acidic sol of pH 1 to 4 obtained by the ion- An amount lower than 1 % results in insufficient for exchange method or the oxidation method, a sol of charging the surface of all the particles to positive, pH 4 to 10 obtained by addition of an organic while the effect is the same even by addition of 50 amine or an alkali metal to an acidic sol or a sol of % or higher and it becomes inconvenient to use pH 4 to 10 containing an organic amine obtained 40 such a sol due to the increment of amount of co- by the peptization method. existing anions. The water-soluble basic salt to be used in the By mixing an acidic sol of pH 1 to 4 with an present invention is that of a trivalent or tetravalent aqueous solution of a basic salt, a sol positively metal, including as the trivalent metal aluminium, charged of pH 0 to 3 can be obtained. This sol is chromium, gallium, indium, tantalum, etc., and, as 45 stable as such, and stability of the sol will not be the tetravalent metal, zirconium, tin, titanium, ger- lowered even when the pH is adjusted to 2 to 5 by manium, cerium, hafnium, thorium, etc. Preferably, addition of a basic substance such as an alkali aluminium and zirconium are used. As anions, metal hydroxide or an organic amine. By con- chloride ions, nitrate ions, sulfate ions, acetate ions, centration of the sol according to the evaporation formate ions, etc., may be used, and chloride ions 50 method or the ultrafiltration method, a sol with a and acetate ions are preferred. Although a basic concetration of Sb2 05 of 30 to 60 % by weight can salt with any composition may be used, it is prefer- be easily obtained. Also, when a sol of pH 4 to 10 able to use a basic salt with little acid content. stabilized with an alkali metal or an organic amine Examples of such basic salts include basic alumin- is mixed with a basic salt, a sol positively charged ium chloride such as AI2(OH)5CI and AI(OH)2CI, 55 of pH 0 to 7 can be obtained. This sol is stable as basic aluminium acetate such as AI(OH)2- such, but its stability can be further improved by (CH3C00)21/3H3B03, basic aluminium nitrate such controlling the pH by addition of an acidic sub- as AI(OH)(N03)2, basic aluminium formate such as stance such as nitric acid, hydrochloric acid, etc.

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Also, according to similar concentration, a highly hours. The resultant milky white colloidal solution concentrated sol can be easily obtained. was found to contain 26.6 % of Sb205 and 1.33 % When the positively charged antimony pentox- of Zr02 (corresponding to 5 % of Sb205), and had ide sol of this invention is mixed with a cationic a pH of 2.4 and a viscosity of 2.8 10-3 Pa.s (2.8 resin emulsion or an aqueous solution of a cationic 5 cp). The sol was also stable at 40 °C for one water-soluble polymer, no agglomeration occurs month. and also, when it is added into an aqueous solution of an inorganic acid such as hydrochloric acid, Example 3 sulfuric acid, nitric acid, etc., or an organic acid such as acetic acid, propionic acid, oxalic acid, io 1500 g of the higyly concentrated antimony maleic acid, etc., an aqueous solution of a metal pentoxide sol (Sb205 41.2 %, Na20 3.0 %, K20 salt or amine salts of these acids or an organic 3.2 %, pH 6.3) obtained by adding potassium hy- solvent such as an alcohol, no agglomeration oc- droxide to the sol used in Example 1, followed by curs but it is well dispersed therein, and therefore it concentration by the ultrafiltration method, was ad- can be applicable for fields in which the antimony 15 ded into a mixture of 202 g of the same aqueous pentoxide sol of the prior art cannot satisfactorily basic aluminium chloride solution and 358 g of be used. water stirred by means of a high speed impeller The present invention is described in more mixer, and the mixture was mixed under stirring for detail by referring to the following examples. How- 3 hours. The resultant milky white colloidal solution ever, the present invention is not limited to these 20 was found to contain 30.0 % of Sb205 and 2.25 % examples. Also, unless otherwise specifically of Al203 (corresponding to 7.5 % of Sb205), and noted, all "%" are based on weight. had a pH of 5.2 and a viscosity of 4.4 10-3 Pa.s (4.4 cp). The sol was also stable at 40 °C for one Example 1 month. 25 To 500 g of an antimony pentoxide sol contain- Example 4 ing no amine (Sb205 10.9 %, Na20 0.79 %, pH 2.2) prepared by the peptization method disclosed 800 g of the highly concentrated sol added in Japanese Unexamined Patent Publication No. with potassium hydroxide used in Example 3 was 41536/1985, 13.6 g of an aqueous aluminium chlo- 30 added into a mixture of 165 g of the aqueous basic ride solution (Takibine: trade name, produced by zirconium acetate solution used in Example 2 and Taki Kagaku; Al203 23.0%, CI 18.0 %, pH 3.4) was 115 g of water stirred by means of a high speed added under stirring by means of a high speed impeller mixer, and the mixture was mixed under impeller mixer and the mixture was stirred for 3 stirring for 2 hours. The resultant milky white col- hours. The resultant milky white colloidal solution 35 loidal solution was found to contain 30.5 % of was found to contain 10.6 % of Sb205 and 0.53 % Sb205 and 2.25 % of Zr02 (corresponding to 7.5 of Al203 (corresponding to 5 % of Sb205) and had % of Sb205), and had a pH of 4.6 and a viscosity a pH of 1 .9. The colloidal solution had a viscosity of 15.9 10-3 Pa.s (15.9 cp). During storage at 40 of 2.2 10-3 Pa.s (2.2 cp) and was stable at 40 °C °C for one month, the Sol was found to be stable, for one month. After 2.7 g of 28 % ammonia water 40 although exibiting thixotropic property. was added to the sol to adjust the pH to 4.6, the sol was concentrated by a rotary evaporator to Example 5 Sb205 of 39.2 %. As a result, the sol became to have a pH of 4.2 and a viscosity of 8.3. 10-3 Pa.s 500 g of the highly concentrated sol added (8.3 cp), and it was also stable at 40 °C for one 45 with potassium hydroxide used in Example 3 was month. added to a solution of 42 g of basic aluminium acetate powder (NIAPROOF: trade name, produced Example 2 by NIACET Co.; Al203 36.8 %, CH3C02H 46.3 %) dissolved in 133 g of water, and the mixture was To 500 g of the antimony pentoxide sol (Sb205 50 mixted under stirring by means of a high speed 29.9 %, Na20 2.1 %, pH 2.2) obtained by con- impeller mixer for 3 hours. The resultant milky centrating the sol used in Example 1 by the evap- white colloidal solution was found to contain 30.5 oration method, 7.35 g of an aqueous basic zirco- % of Sb205 and 2.29 % of Al203 (corresponding to nium acetate (Zirconyl Acetate S-20: trade name, 7.5 % of Sb205), and had pH of 5.8 and a viscosity produced by Shinnippon Kinzoku Kagaku K.K.; 55 of 21.1 10-3 Pa.s (21.1 cp). The sol was also found Zr02 20.3 %, CH3COOH 14.7 %, pH 3.1) was to be stable at 40 °C for one month. added under stirring by means of a high speed impeller mixer and the mixture was stirred for 3 Example 6

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300 g of a highly concentrated antimony pen- Example 9 toxide sol (Sb205 51.3 %, Na20 3.8 %, triethanolamine 2.4 %, pH 6.2) prepared by the 300 g of the highly concentrated antimony pen- peptization method was added to 86 g of an aque- toxide sol prepared by the peptization method (the ous basic zirconium acetate solution (the same as 5 same as in Example 6) was added to a mixture of in Example 2) while stirring by means of a high 77 g of an aqueous solution of a reagent of basic speed impeller mixer, and the mixture was stirred zirconium chloride containing 20 % of Zr02 (pH 1 for 3 hours. The resultant milky white colloidal or less) and 136 g of water under stirring by means solution was found to contain 40.4 % of Sb205 and of a high speed impeller mixer, followed further by 4.52 % of Zr02 (corresponding to 11 % of Sb205), io mixing for 1 hour. The resultant milky white col- and had a pH of 4.2 and a viscosity of 0,2 pa (200 loidal solution was found to contain 30.0 % of cp). The sol was stable during storage at 40 °C for Sb205 and 3.0 % of Zr02 (corresponding to 10 % one month, but it exibited strong thixotropic prop- of Sb205), and had a pH of 0.7 and a viscosity of erty. When 7.7 g of a reagent of 60 % nitric acid 3.9 10-3 Pa.s (3.9 cp). The sol was also found to was added to the sol and mixed under stirring, the is be stable during storage at 40 °C for one month. pH became 1.4 and the viscosity 17.1 10-3 Pa.s (17.1 cp). When this was stored at 40 °C one Example 10 month, no thixotropic property was exibited. Thus, improvement could be obserbed with respect to 325 g of a highly concentrated antimony pen- stability. 20 toxide sol (Sb205 48.6 %, triethanolamine 9.5 %, pH 9.5) prepared by the peptization method was Example 7 added into a mixed solution of 156 g of the basic zirconium acetate (the same as in Example 2) and 300 g of a highly concentrated antimony pen- 328 g of water under stirring by means of a high toxide sol (Sb205 48.0 %, Na20 2.8 %, 25 speed impeller mixer, followed further by mixing for triethanolamine 1.1 %, pH 5.8) prepared by the ion- 2 hours. The resultant milky white colloid solution exchange method and stabilized with was found to contain 19.5 % of Sb205 and 3.9 % triethanolamine was added into a mixture of 73 g of of Zr02 (corresponding to 20 % of Sb205), and the aqueous basic zirconium acetate solution (the had a pH of 5.2 and a viscosity of 10.0 10-3 Pa.s same as in Example 2) and 113 g of water stirred 30 (10.0 cp). by a high speed impeller mixer, and the mixture was further stirred for 1 hour. The resultant milky Example 1 1 white colloidal solution was found to contain 30.0 % of Sb205 and 3.05 % of Zr02 (corresponding to To 500 g of an antimony pentoxide sol (Sb205 10 % of Sb205), and had a pH of 4.2 and a 35 22.1 %, pH 1.36) obtained by the H202 oxidation viscosity of 29.6 10-3 Pa.s (29.6 cp). The sol was method, 13.6 g of the aqueous basic aluminium also found to be stable during storage at 40 °C for chloride solution (the same as in Example 1) was one month, although exhibiting thixotropic property. added under stirring by means of a high speed impeller mixer, followed further by stirring for 2 Example 8 40 hours. The resultant milky white colloidal solution was found to contain 21.5 % of Sb205 and 0.61 % 1800 g of the highly concentrated antimony of Al203 (corresponding to 2.8 % of Sb205), and pentoxide sol prepared by the peptization method had a pH of 1.8 and a viscosity of 3.8 10-3 Pa.s (the same as in Example 6) was added to a mixture (3.8 cp). of 231 g of the aqueous basic zirconium acetate 45 solution (the same as in Example 2) and an aque- [Evaluation of Dispersibility of Antimony Pentoxide ous solution of 126 g of the basic aluminium ace- Sol] tate powder (the same as in Example 5) dissolved in 873 g of water under stirring by means of a high Dispersibility of each sol from Example 1 to speed impeller mixer, followed further by mixing for 50 Example 11 in nitric acid and a cationic resin 3 hours. The resultant milky white colloidal solution emulsion was examined. There was employed the was found to contain 30.5 % of Sb205, 1.5 % of method in which 50 g of nitric acid or a cationic Zr02 (corresponding to 5 % of Sb205) and 1.5 % resin emulsion (Neoprene latex 950 produced by of Al203 (corresponding to 5% of Sb205), and had Showa Neoprene K.K.) was sampled in 100 ml a pH of 4.9 and a viscosity of 6.9 10-3 Pa.s (6.9 55 beaker, 50 g of the antimony pentoxide sol was cp). The sol was also stable during storage at 40 added under stirring with the magnetic stirrer and °C for one month. the mixed state was observed. For the purpose of comparison, dispersibility was tested in the same

5 9 EP 0 197 503 B1 10 manner for the antimony pentoxide sol used in group consisting of basic aluminium chloride, Example 1 as Comparative Example 1, the highly basic aluminium acetate, basic aluminium ni- concentrated antimony pentoxide sol stabilized with trate, basic aluminium formate, basic zirconium potassium hydroxide used in Example 3 as Com- chloride, basic zirconium acetate, basic zirco- parative Example 2, and the highly concentrated 5 nium nitrate, basic titanium chloride and basic antimony pentoxide sol stabilized with titanium acetate. triethanolamine used in Example 7 as Comparative Example 3. Revendications As the result, each of the antimony pentoxide sols positively charged obtained in Examples 1 to io 1. Un sol de pentoxyde d'antimoine charge positi- 11 was dispersed without agglomeration, but gela- vement, caracterise en ce qu'il comprend des tion occured for the antimony pentoxide sols of particules colloTdales de sol de pentoxyde Comparative Examples 1 to 3. d'antimoine revetues sur leurs surfaces avec au moins un des metaux trivalents et tetrava- Claims 15 lents, la teneur desdits metaux etant de 1 a 50 % en poids d'oxyde metallique par rapport au 1. A positively charged antimony pentoxide sol, pentoxyde d'antimoine dans ledit sol de pen- comprising colloidal particles of antimony pentoxyde d'antimoine. toxide sol coated on their surfaces with at least one of trivalent and tetravalent metals, the con- 20 2. Le sol de pentoxyde d'antimoine charge positi- tent of said metals being 1 to 50 % by weight vement selon la revendication 1 , caracterise en in terms of the metal oxide based on antimony ce qu'il contient ledit pentoxyde d'antimoine en pentoxide in said antimony pentoxide sol. quantite de 1 a 60 % en poids.

2. The positively charged antimony pentoxide sol 25 3. Le sol de pentoxyde d'antimoine charge positi- according to Claim 1, wherein said antimony vement selon la revendication 1 , caracterise en pentoxide is contained in an amount of 1 to 60 ce que lesdites particules colloTdales revetues % by weight. avec ledit metal ont une dimension moyenne de particule de 5 a 150 nm. 3. The positively charged antimony pentoxide sol 30 according to Claim 1, wherein said colloidal 4. Le sol de pentoxyde d'antimoine charge positi- particles coated with said metal have an aver- vement selon la revendication 1 , caracterise en age particle size of 5 to 150 mum. ce que ledit sol de pentoxyde d'antimoine charge positivement a un pH de 7 ou moins. 4. The positively charged antimony pentoxide sol 35 according to Claim 1, wherein said positively 5. Un procede pour preparer un sol de pentoxyde charged antimony pentoxide sol has the pH d'antimoine charge positivement, caracterise value of 7 or less. en ce qu'il consiste a melanger un sol de pentoxyde d'antimoine de pH 1 a 10 contenant 5. A process for preparing a positively charged 40 5 a 60 % en poids de pentoxyde d'antimoine antimony pentoxide sol, which comprises mix- et une solution aqueuse d'au moins un des ing an antimony pentoxide sol of pH 1 to 10 sels basiques de metaux trivalents et tetrava- containing 5 to 60 % by weight of antimony lents dans des proportions telles que la quanti- pentoxide and an aqueous solution of at least te dudit sel puisse etre de 1 a 50 % en poids one of basic salts of trivalent and tetravalent 45 en oxyde metallique par rapport au pentoxyde metals at proportions such that the amount of d'antimoine dans ledit sol pentoxyde d'antimoi- said basic salt may be 1 to 50 % by weight in ne. terms of the metal oxide based on antimony pentoxide in said antimony pentoxide sol. 6. Le procede selon la revendication 5, caracteri- 50 se en ce que lesdits metaux trivalents et tetra- 6. The process according to Claim 5, wherein valents sont choisis parmi I'aluminium, le chro- said trivalent and tetravalent metals are se- me, le gallium, I'indium, le tantale, le zirco- lected from the group consisting of aluminium, nium, I'etain, le titane, le germanium, le ce- chromium, gallium, indium, tantalum, zirco- rium, I'hafnium et le thorium. nium, tin, titanium, germanium, cerium, haf- 55 nium and thorium. 7. The process according to 7. Le procede selon la revendication 6, caracteri- Claim 6, wherein said basic salts of trivalent se en ce que lesdits sels basiques de metaux and tetravalent metals are selected from the trivalents et tetravalents sont choisis parmi le

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chlorure basique d'aluminium, I'acetate basi- 7. Verfahren nach Anspruch 6, que d'aluminium, le nitrate basique d'alumi- dadurch gekennzeichnet, da/S die basischen nium, le formiate basique d'aluminium, le chlo- Salze aus den trivalenten und tetravalenten rure basique de zirconium, I'acetate basique Metallen aus der Gruppe ausgewahlt werden, de zirconium, le nitrate basique de zirconium, 5 die aus basischem Aluminiumchlorid, basi- le chlorure basique de titane et I'acetate basischem Aluminiumacetat, basischem Alumini- que de titane. umnitrat, basischem Aluminiumformiat, basischem Zirkoniumchlorid, basischem Zirkoni- Patentanspruche umacetat, basischem Zirkoniumnitrat, basi- io schem Titanchlorid und basischem Titanacetat 1. Positiv geladenes Antimonpentoxidsol, umfas- besteht. send kolloide Teilchen aus Antimonpentoxid- sol, die auf ihren Oberflachen mit zumindest einem von trivalenten und tetravalenten Metal- len beschichtet sind, wobei der Gehalt der 15 Metalle 1 bis 50 Gew.% ist, ausgedruckt in Metalloxid, bezogen auf Antimonpentoxid in dem Antimonpentoxidsol.

2. Positiv geladenes Antimonpentoxidsol nach 20 Anspruch 1, dadurch gekennzeichnet, da/S das Antimon- pentoxid in einer Menge von 1 bis 60 Gew.% enthalten ist. 25 3. Positiv geladenes Antimonpentoxidsol nach Anspruch 1, dadurch gekennzeichnet, da/S die kolloiden Teilchen, die mit dem Metall beschichtet sind, eine durchschnittliche Teilchengro/Se von 5 bis 30 150 mum aufweisen.

4. Positiv geladenes Antimonpentoxidsol nach Anspruch 1, dadurch gekennzeichnet, da/S das positiv ge- 35 ladene Antimonpentoxidsol einen pH-Wert von 7 oder weniger aufweist.

5. Verfahren zur Herstellung eines positiv gela- denen Antimonpentoxidsols, umfassend das 40 Vermischen eines Antimonpentoxidsols mit einem pH von 1 bis 10, das 5 bis 60 Gew.% Antimonpentoxid enthalt, und eine wassrige Losung aus zumindest einem basischen Salz von trivalenten und tetravalenten Metallen mit 45 Anteilen, so da/S die Menge des basischen Salzes 1 bis 50 Gew.% sein kann, ausgedruckt in Metalloxid, bezogen auf Antimonpentoxid in dem Antimonpentoxidsol. 50 6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, da/S die trivalenten und tetravalenten Metalle aus der Gruppe ausgewahlt werden, die aus Aluminium, Chrom, Gallium, Indium, Tantal, Zirkonium, Zinn, Titan, 55 Germanium, Cer, Hafnium und Thorium besteht.