US 2010O288795A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2010/0288795 A1 LOrtz et al. (43) Pub. Date: Nov. 18, 2010 (54) SILICON DIOXIDE DISPERSION (30) Foreign Application Priority Data (75) Inventors: Wolfgang Lortz, Waechtersbach Jan. 31, 2008 (DE) ......................... 102O08OO6883.7 (DE); Jochen Scheffler, Alzenau (DE); Gabriele Perlet, Publication Classification Grosskrotzenburg (DE) (51) Int. Cl. Correspondence Address: AOIN 25/04 (2006.01) OBLON, SPIVAK, MCCLELLAND MAIER & AOIN 25/06 (2006.01) NEUSTADT, L.L.P. AOIP 7/02 (2006.01) 194O DUKE STREET AOIP 7/04 (2006.01) ALEXANDRIA, VA 22314 (US) B65D 83/14 (2006.01) (73) Assignee: EVONIK DEGUSSA GmbH, Essen (DE) (52) U.S. Cl. ......................................... 222/394: 514/770 (21) Appl. No.: 12/863,096 (57) ABSTRACT (22) PCT Filed: Dec. 30, 2008 Dispersion comprising hydrophobic pyrogenically prepared (86). PCT No.: PCT/EP2008/068344 silicon dioxide, alcohol and at least one additive which pro motes the dispersion and, as additional component, at least S371 (c)(1), one insecticide and/or acaricide. The dispersion can be (2), (4) Date: Jul. 15, 2010 canned in spray cans and used as insecticide. US 2010/0288795 A1 Nov. 18, 2010 SILICON DOXDE DISPERSION 0011. In addition, during storage, an approximately 40% larger storage space has to be taken into account. 0012. Furthermore, with an air-comprising dispersion, it is 0001. The invention relates to a silicon dioxide dispersion, not possible to achieve a homogeneous bubble-free coverage to a process for the preparation thereof and to the use thereof. of surfaces to be treated. 0002 Pulverulent hydrophobic silica is used to combat (0013 DE 10 2004 021532 describes a dispersion which, Sucking insects, the application taking place by means of in addition to water, comprises 0.5 to 20% by weight of dusting (DE 3835592). hydrophobic silica, 0.01 to 10% by weight of a gelling or 0003 Disadvantageously, dust development is such that viscosity-increasing additive, 0.1 to 1% by weight of a pre this method of insect control finds little acceptance. 0004. The aqueous dispersions likewise described in DE servative and 0 to 1% by weight of a surface-active substance. 3835592, which consist of a hydrophobic silica and water, do 0014. This dispersion can be used as insecticide against not exhibit satisfactory stability. mites and other insects. 0005 U.S. Pat. No. 5,830,512 describes a dispersion in 0015. It is successfully used in spacious animal houses and which satisfactory stability is achieved by addition of hydro on large Surfaces, it being possible to use appropriately large philic Substances, such as, for example, silicas. However, the caliber sprayers (such as garden sprayers) for the spraying. active hydrophobic component is through this diluted by a 0016. When used in the field of pets, where the area to be hydrophilic substance. Furthermore, only a very low stability treated is rather Small, large-caliber sprayers. Such as, for of the dispersion, from hours to a few days, is achieved. example, garden sprayers, cannot be used. 0006 EP 1250 048 describes stabilizing the dispersion of 0017. In addition, pump spray bottles are not suitable hydrophobic silicon dioxide through gelling additives, such because the necessary spraying pressure of more than 3 bar as, for example, Xanthan gum, Sodium alginates or neutral usually cannot be achieved. Accordingly, a good spray mist ized carboxyvinyl polymers, mixtures of these additives also cannot be achieved and accordingly also a uniform covering being possible. of the cage area to be sprayed/treated cannot be achieved. 0007. These gelling additives bring about, by interaction 0018. It is known to spray a pet cage area with a dispersion with the hydrophobic SiO particles and the incorporated air, sold under the name "Decimite Aerosol'. a marked structural viscosity which is exhibited when apply 0019. This dispersion consists of an aqueous dispersion of ing by spraying. Thus, during the spraying process, the vis a few percent of hydrophilic silica. This dispersion has the cosity of the dispersion is relatively low at the shear forces disadvantage that it takes too long to dry. Furthermore, it has acting on it. After the dispersion drops impact the Surface to an excessively high viscosity and also excessively poor spray be coated, the Viscosity again increases strongly, in order to formation. avoid dripping/running off from in particular vertical Sur 0020. Furthermore, because of the water content of the faces. dispersion, the spray can has to be lacquered on the inside. 0008. According to EP 1250.048, in addition to the hydro 0021. The object was accordingly to prepare a dispersion phobic SiO particles to be dispersed, large amounts of air are with an insecticidal action which can be satisfactorily sprayed incorporated. With the known dispersion processes, this can on Small Surfaces and also can quickly develop its action. not be avoided without the use of wetting surfactants and 0022. A subject-matter of the invention is a dispersion antifoaming agents. Thus, in Example 1, a density of only 0.6 comprising hydrophobic pyrogenically prepared silicon g/ml is specified, which means that approximately 40% of the dioxide, alcohol and at least one additive which promotes the Volume consists of air. dispersing. 0009. In order to achieve a satisfactory activity, a mini mumweight has to be applied to the Surfaces to be sprayed. If, 0023. Use may be made, as hydrophobic pyrogenically per spraying operation, only approximately 60% of the Vol prepared silicon dioxide, of Aerosil R. R805, Aerosil R. R974, ume of the spraying appliances can be used, this represents a Aerosil(R) R202, Aerosil(R) R812, Aerosil(R) R812S and Aero significant reduction in the effectiveness. SilR) R8200. 0010 Disadvantageously, the transportation, packaging 0024. Use may in particular be made of Aerosil R. R812S. and waste disposal costs of the required packaging are higher 0025. The physicochemical characteristics of these pyro by this proportion. genically prepared silicon dioxides are listed in Table 1. TABLE 1. Test method Aerosil (R Aerosil (R Aerosil (R Aerosil (R Aerosil (R Aerosil (R) R974 R2O2 R805 R812 R812S R82OO Behaviour with regard to water hydrophobic Appearance loose white powder BET surface m°g 1702O 100 - 20 150 - 25 260 30 220 25 16O 25 Mean size of the ill 12 14 12 7 7 primary particles Tamped density approximate value Normal product gll 50 50 50 50 50 140 Compacted product gll 90 (additive “V) US 2010/0288795 A1 Nov. 18, 2010 TABLE 1-continued Test method Aerosil (R Aerosil (R Aerosil (R Aerosil (R Aerosil (R Aerosil (R) R974 R2O2 R8OS R812 R812S R82OO Loss on drying % by weight sO.S sO.S sO.S sO.S sO.S sO.S (2 hours at 105° C.) on leaving the Supplier Loss on ignition'' % by weight s2 4-6 5-7 1.0-2.5 1.5-3.0 (2 hours at 1000° C.) C content % by weight 0.7-1.3 3.S.-S.O 4.5-6.5 2.0-3.0 3.0-4.O 2.0-4.0 pH 5) 10) 3.7-4.7 4-6 3.5-5.5 5.5-7.5 5.5-7.5 e5.0 SiO,8) % by weight 299.8 a 99.8 a 99.8 a 99.8 a 99.8 a 99.8 Al-O. % by weight sO.OS sO.OS sO.OS sO.OS sO.OS sO.OS FeO, % by weight sO.O1 sO.O1 sO.O1 sO.O1 sO.O1 sO.O1 TiO,8) % by weight sO.O3 sO.O3 sO.O3 sO.O3 sO.O3 sO.O3 HC II) % by weight s:0.1 sO.O2S s).O2S seO.O2S s).O2S s().O2S following DIN 66131 2 following DIN ISO 787/11, JIS K 5101/18 (not sieved) 3) following DIN ISO 7872, ASTMD 280, JIS K 5101:21 4) following DIN 55921, ASTMD 1208, JIS K 5101.23 5) following DIN ISO 7879, ASTMD 1208, JIS K 5101/24 based on the substance dried at 105° C. for 2 hours based on the substance ignited at 1000°C, for 2 hours 'in waterimethanol = 1:1 'HCl content is constituent of the loss on ignition 12) v. product is supplied in bags of 15 kg net 0026. The following can be used as alcohol: methanol, step is the trimethylsilyl group transferred. Trimethylsilyl ethanol, propanol, isopropanol, 1-butanol, 2-methyl-1-pro groups not reacted with SiOH Surface groups are themselves panol, 2-butanol and 2-methyl-2-propanol. inactivated by dimerization. 0027. Use may in particular be made of low-boiling-point 0034. The following silanes can be used as additional alcohols, such as, for example, ethanol. silanes: 0028. In order to make possible good dispersing, it is, 0035) a) organosilanes of the (RO)Si(CH) and however, necessary to add an additive which promotes the (RO)SiOCH) type dispersion, which additive covers remaining areas or new 0036 R-alkyl, such as, for example, methyl, ethyl, areas, not surface-modified, produced by the dispersing. The n-propyl, isopropyl or butyl, addition of hexamethyldisilaZane (HMDS) has proven to be 0037 n=1-20 very advantageous for this. (0038 b) organosilanes of the R',(RO), Si(C.H.) and 0029. The HMDS results, by this additional silanization, R',(RO), Si(CH2) type in a virtually perfect Surface modification, through which a 0039) R-alkyl, such as, for example, methyl, ethyl, considerably lower viscosity is achieved. If appropriate, any n-propyl, isopropyl or butyl excess HMDS can be converted by alcoholysis to give trim 0040 R-alkyl, such as, for example, methyl, ethyl, ethylethoxysilane, trimethylsilanol or hexamethyldisiloxane, n-propyl, isopropyl or butyl and NH.