~" ' Nil II II II III Ml Nil INI Ml Ml J European Patent Office *m _ _ _ © Publication number: 0 197 503 B1 Office_„. europeen des brevets EUROPEAN PATENT SPECIFICATION © Date of publication of patent specification: 15.07.92 © Int. CI.5: C01G 30/00 © Application number: 86104529.2 @ Date of filing: 03.04.86 © Positively charged antimony pentoxlde sol and preparation thereof. ® 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) 00 CO o m 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 2 3 EP 0 197 503 B1 4 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.