FLUORINE-CONTAINING TITANIUM OXIDE - NANO-SILICA COMPOSITE PARTICLES AND METHOD FOR PRODUCING THE SAME

Abstract

Fluorine-containing titanium oxidenano-silica composite particles comprising a condensate of a fluorine-containing alcohol and an alkoxysilane, and titanium oxide and nano-silica particles, wherein the fluorine-containing alcohol is represented by the general formula:

R.sub.FAOH[I]

(wherein R.sub.F is a perfluoroalkyl group having 6 or less carbon atoms, or a polyfluoroalkyl group, in which some of the fluorine atom or atoms of the perfluoroalkyl group are replaced by a hydrogen atom or atoms, and which contains a terminal perfluoroalkyl group having 6 or less carbon atoms and a perfluoroalkylene group having 6 or less carbon atoms; and A is an alkylene group having 1 to 6 carbon atoms). The fluorine-containing titanium oxidenano-silica composite particles do not have difficulty in handling as with hydrogen fluoride, can be produced by using a fluorine-containing alcohol, which can be easily handled, and can produce a product capable of suppressing a decrease in the function of the titanium oxide as a photocatalyst even when subjected to a high-temperature heat treatment.

Claims

1. Fluorine-containing titanium oxidenano-silica composite particles comprising a condensate of a fluorine-containing alcohol and an alkoxysilane, and titanium oxide and nano-silica particles, wherein the fluorine-containing alcohol is represented by the general formula:
R.sub.FAOH[I] (wherein R.sub.F is a perfluoroalkyl group having 6 or less carbon atoms, or a polyfluoroalkyl group, in which some of the fluorine atom or atoms of the perfluoroalkyl group are replaced by a hydrogen atom or atoms, and which contains a terminal perfluoroalkyl group having 6 or less carbon atoms and a perfluoroalkylene group having 6 or less carbon atoms; and A is an alkylene group having 1 to 6 carbon atoms).

2. The fluorine-containing titanium oxidenano-silica composite particles according to claim 1, wherein the fluorine-containing alcohol represented by the general formula [I] is a polyfluoroalkyl alcohol represented by the general formula:
C.sub.nF.sub.2n+1(CH.sub.2).sub.jOH[II] wherein n is an integer of 1 to 6 and j is an integer of 1 to 6.

3. The fluorine-containing titanium oxidenano-silica composite particles according to claim 1, wherein the fluorine-containing alcohol represented by the general formula [I] is a polyfluoroalkyl alcohol represented by the general formula:
C.sub.nF.sub.2n+1(CH.sub.2CF.sub.2).sub.a(CF.sub.2CF.sub.2).sub.b(CH.sub.2CH.sub.2).sub.cOH[III] wherein n is an integer of 1 to 6, a is an integer of 1 to 4, b is an integer of 0 to 2, and c is an integer of 1 to 3.

4. The fluorine-containing titanium oxidenano-silica composite particles according to claim 1, wherein the alkoxysilane is a silane derivative represented by the general formula:
(R.sub.1O).sub.pSi(OR.sub.2).sub.q(R.sub.3).sub.r[IV] wherein R.sub.1 and R.sub.3 are each a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group; R.sub.2 is an alkyl group having 1 to 6 carbon atoms or an aryl group, with the proviso that not all of R.sub.1, R.sub.2 and R.sub.3 are aryl groups; and p+q+r is 4, with the proviso that q is not 0.

5. The fluorine-containing titanium oxidenano-silica composite particles according to claim 1, wherein 10 to 200 parts by weight of nano-silica particles, 10 to 200 parts by weight of fluorine-containing alcohol, and 10 to 200 parts by weight of alkoxysilane are used based on 100 parts by weight of titanium oxide.

6. The fluorine-containing titanium oxidenano-silica composite particles according to claim 1, wherein 50 to 150 parts by weight of nano-silica particles, 50 to 150 parts by weight of fluorine-containing alcohol, and 50 to 150 parts by weight of alkoxysilane are used based on 100 parts by weight of titanium oxide.

7. A method for producing fluorine-containing titanium oxidenano-silica composite particles, the method comprising subjecting the fluorine-containing alcohol [I] according to claim 1 and an alkoxysilane to a condensation reaction in the presence of titanium oxide and nano-silica particles using an alkaline or acidic catalyst.

8. Fluorine-containing titanium oxidenano-silica composite particles comprising a condensate of a fluorine-containing alcohol and an alkoxysilane, and titanium oxide and nano-silica particles, wherein the fluorine-containing alcohol is represented by the general formula:
R.sub.FAOH[Ia] or the general formula:
HOAR.sub.FAOH[Ib] wherein R.sub.F' is a linear or branched perfluoroalkyl group containing a terminal perfluoroalkyl group having 6 or less carbon atoms and a perfluoroalkylene group having 6 or less carbon atoms, and containing an O, S or N atom; R.sub.F is a linear or branched perfluoroalkylene group containing a perfluoroalkylene group having 6 or less carbon atoms, and containing an O, S or N atom; and A is an alkylene group having 1 to 6 carbon atoms.

9. The fluorine-containing titanium oxidenano-silica composite particles according to claim 8, wherein the fluorine-containing alcohol represented by the general formula [la] is a hexafluoropropene oxide oligomer alcohol represented by the general formula:
C.sub.mF.sub.2m+1O[CF(CF.sub.3)CF.sub.2O].sub.dCF(CF.sub.3)(CH.sub.2).sub.eOH[IIa] wherein m is an integer of 1 to 3, d is an integer of 0 to 100, and e is an integer of 1 to 3.

10. The fluorine-containing titanium oxidenano-silica composite particles according to claim 8, wherein the fluorine-containing alcohol represented by the general formula [Ib] is a perfluoroalkylene ether diol represented by the general formula:
O(CH.sub.2).sub.fCF(CF.sub.3)[OCF.sub.2CF(CF.sub.3)].sub.gO(CF.sub.2).sub.hO[CF(CF.sub.3)CF.sub.2O].sub.iCF(CF.sub.3)(CH.sub.2).sub.fOH[IIb] wherein f is an integer of 1 to 3, g+i is an integer of 0 to 50, and h is an integer of 1 to 6.

11. The fluorine-containing titanium oxidenano-silica composite particles according to claim 8, wherein the alkoxysilane is a silane derivative represented by the general formula:
(R.sub.1O).sub.pSi(OR.sub.2).sub.q(R.sub.3).sub.r[IV] wherein R.sub.1 and R.sub.3 are each a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group; R.sub.2 is an alkyl group having 1 to 6 carbon atoms or an aryl group, with the proviso that not all of R.sub.1, R.sub.2 and R.sub.3 are aryl groups; and p+q+r is 4, with the proviso that q is not 0.

12. The fluorine-containing titanium oxidenano-silica composite particles according to claim 8, wherein 10 to 200 parts by weight of nano-silica particles, 10 to 200 parts by weight of fluorine-containing alcohol, and 10 to 200 parts by weight of alkoxysilane are used based on 100 parts by weight of titanium oxide.

13. The fluorine-containing titanium oxidenano-silica composite particles according to claim 8, wherein 50 to 150 parts by weight of nano-silica particles, 50 to 150 parts by weight of fluorine-containing alcohol, and 50 to 150 parts by weight of alkoxysilane are used based on 100 parts by weight of titanium oxide.

14. A method for producing fluorine-containing titanium oxidenano-silica composite particles, the method comprising subjecting the fluorine-containing alcohol [Ia] or [Ib] according to claim 8 and an alkoxysilane to a condensation reaction in the presence of titanium oxide and nano-silica particles using an alkaline or acidic catalyst.

15. A surface-treating agent comprising the fluorine-containing titanium oxidenano-silica composite particles according to claim 1, as an active ingredient.

16. A surface-treating agent comprising the fluorine-containing titanium oxidenano-silica composite particles according to claim 8, as an active ingredient.

Description

EXAMPLES

[0094] The following describes the present invention with reference to Examples.

Example 1

[0095] CF.sub.3(CF.sub.2).sub.5(CH.sub.2).sub.2OH [FA-6] 250mg (0.69 mmol) was added and dissolved in 30 ml of methanol. To the resulting solution, 250 mg of anatase type titanium oxide and 834 mg (250 mg as nano-silica) of silica sol (Methanol Silica Sol, a product of Nissan Chemical Industries, Ltd.; nano-silica content: 30 wt. %, average particle diameter: 11 nm) and 0.25 ml (1.13 mmol) of tetraethoxysilane (a product of Tokyo Chemical Industry Co., Ltd.; density: 0.93 g/ml) were added. While stirring the mixture with a magnetic stirrer, 0.5 ml of 25 wt. % aqueous ammonia was added, and the mixture was reacted for 5 hours.

[0096] After completion of the reaction, the methanol and aqueous ammonia were removed using an evaporator under reduced pressure, and the resulting powder was redispersed in approximately 10 ml of methanol overnight. The next day, centrifugation was performed using a centrifuge tube, the supernatant was removed, and fresh methanol was added to perform rinsing. After rinsing was performed 3 times, the opening of the centrifuge tube was covered with aluminum foil, and the tube was placed in an oven at 70 C. overnight. The next day, the tube was placed and dried in a vacuum dryer at 50 C. overnight, thereby obtaining 537 mg (yield: 73%) of white powder.

[0097] The particle size of the obtained white powdery fluorine-containing titanium oxidenano-silica composite particles, and the variation of the particle size were measured in a methanol dispersion having a solid matters content of 1 g/L at 25 C. by a dynamic light scattering (DLS) measurement method. Further, thermogravimetric analysis (TGA) was performed before and after the calcining of 1000 C. The heating rate in this case was 10 C./min. The particle diameter after calcining is an average value of two values, except for Example 1. Moreover, the percentage of the weight loss due to calcining with respect to the initial weight was also calculated.

Examples 2 to 7, Reference Examples 1 to 2

[0098] In Example 1, the same amount (250 mg) of various fluorine-containing alcohols were used in place of FA-6.

FA-8:CF.sub.3(CF.sub.2).sub.7(CH.sub.2).sub.2OH
DTFA: CF.sub.3(CF.sub.2).sub.3CH.sub.2(CF.sub.2).sub.5(CH.sub.2).sub.2OH [CF.sub.3(CF.sub.2).sub.3(CH.sub.2CF.sub.2)(CF.sub.2CF.sub.2).sub.2(CH.sub.2CH.sub.2)OH)]
PO-6-OH: HOCH.sub.2CF(CF.sub.3) [OCF.sub.2CF(CF.sub.3)] .sub.nOCF.sub.2CF.sub.2O [CF(CF.sub.3)CF.sub.2O] .sub.mCF(CF.sub.3)CH.sub.2OH (n+m=6)
PO-9M-OH: HOCH.sub.2CF(CF.sub.3) [OCF.sub.2CF(CF.sub.3)] .sub.nOCF.sub.2CF.sub.2O [CF(CF.sub.3)CF.sub.2O] .sub.mCF(CF.sub.3)CH.sub.2OH (n+m=9)

[0099] The results of the foregoing individual Examples and Reference Examples are shown in the following Table 1.

TABLE-US-00001 TABLE 1 Fluorine-containing TiO.sub.2SiO.sub.2 composite particle size (nm) Fluorine-containing Recovery After Loss Alcohol amount Yield Before calcining of Weight Ex. Abbreviation mM (mg) (%) Calcining 1000 C. (%) Ex. 1 FA-6 0.69 537 73 22.5 5.4 22.4 5.1 5 Ref. Ex. 1 FA-8 0.54 507 69 78.4 11.3 4 Ref. Ex. 2 FA-8 0.54 492 67 85.2 10.0 93.4 22.5 4 Ex. 2 DTFA 0.47 537 73 52.0 7.2 5 Ex. 3 DTFA 0.47 529 72 27.7 6.5 103.1 22.9 5 Ex. 4 PO-6-OH 0.26 515 70 25.6 5.4 22 Ex. 5 PO-6-OH 0.26 537 73 26.6 5.8 81.0 17.5 6 Ex. 6 PO-9M-OH 0.17 434 59 38.2 10.9 31 Ex. 7 PO-9M-OH 0.17 198 27 49.3 16.1 57.7 14.1 27

[0100] Moreover, the photocatalytic function of the obtained fluorine-containing titanium oxidenano-silica composite particles was evaluated by a methylene blue degradation reaction in the following manner.

[0101] A methanol solution of 0.8 ml of methylene blue (concentration: 0.01 g/cm.sup.3) and a methanol solution of 0.4 ml of composite particles (concentration: 0.20 g/cm.sup.3) were weighed and diluted with methanol so that the total solution was 3.2 ml of methanol solution. The prepared solution (weight ratio of methylene blue/composite particles = 1/10) was irradiated with ultraviolet ray having a wavelength of 365 nm for 20 minutes. Changes with time of the absorption peak (652 nm) of methylene blue in UV spectral measurement were plotted in a graph, thereby evaluating the function of the composite particles as a photocatalyst (degradation rate and evaluation based thereon). The function evaluation was conducted before and after the calcining of 1,000 C., and the results were evaluated in the following evaluation criteria. (Evaluation criteria)

[0102] : The performances were improved compared with the anatase type titanium oxide

[0103] : One of the performances was improved compared with the anatase type titanium oxide

[0104] : The performances were equivalent compared with the anatase type titanium oxide

[0105] X: The performances were reduced compared with the anatase type titanium oxide

TABLE-US-00002 TABLE 2 Before calcining After calcining Degradation rate Degradation rate Ex. (%) Evaluation (%) Evaluation Ex. 1 82 42 Ref. 82 69 Ex. 1 Ex. 3 86 57 Ex. 5 80 75 Ex. 7 71 79

[0106] The degradation rate of the anatase type titanium oxide was 71% before the calcining and 10% after the calcining. The degradation rate of the anatase type titanium oxide/boric acid (weight ratio=1:0.94) was 82% before the calcining and 31% after the calcining.