JP2014196479A - Fluorine-containing nano silica composite particle and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorine-containing nano silica composite particle using a fluorine-containing alcohol having excellent water- and oil-repellent performance, where one with a perfluoroalkyl group having a carbon number of less than 8 generates no perfluorooctanoic acid nor the like even when released in the environment, and a production method thereof.SOLUTION: A fluorine-containing nano silica composite particle is produced by condensation reaction of a fluorine-containing alcohol R-A-OH (R: a perfluoroalkyl group, and A: an alkylene group) with alkoxysilane in the presence of a nano silica particle by using an alkaline or acidic catalyst.

Description

  The present invention relates to fluorine-containing nanosilica composite particles and a method for producing the same. More specifically, the present invention relates to fluorine-containing nanosilica composite particles using a fluorine-containing alcohol and a method for producing the same.

  Patent Document 1 discloses a liquid, fluorine-containing and single-component composition having a fluorine content of 5 to 75% by mass relative to a solid resin for permanent oil- and water-resistant surface treatment of porous and non-porous substrates. In combination with a suitable stabilizing component and a hydrophilic silane component, a composition having excellent storage stability, hydrophobicity, oleophobicity and dust resistance is described.

However, here, when preparing a surface treatment agent for mineral and non-mineral bases, a silyl group is introduced into the fluorine compound by using a highly toxic isocyanate compound. Therefore, it is necessary to prepare the production environment for the implementation. Further, perfluorooctanoic acid, which is currently required to be reduced from the environmental viewpoint, and a fluorine-containing alcohol having a C ₈ or more perfluoroalkyl group, which is a precursor thereof, are used.

Special table 2011-511113 gazette Japanese Patent No. 4673604

  It is an object of the present invention to have excellent water and oil repellency, and when perfluoroalkyl group has less than 8 carbon atoms, it does not produce perfluorooctanoic acid or the like even when released into the environment. An object of the present invention is to provide fluorine-containing nanosilica composite particles using a fluorine-containing alcohol and a method for producing the same.

According to the invention, the general formula
R _F -A-OH (I)
(Wherein R _F is a perfluoroalkyl group and A is an alkylene group), fluorine-containing nanosilica composite particles comprising a condensate of a fluorine-containing alcohol and an alkoxysilane with nanosilica particles are provided.

  Such fluorine-containing nanosilica composite particles are produced by a method in which the fluorine-containing alcohol [I] and alkoxysilane are subjected to a condensation reaction using an alkaline or acidic catalyst in the presence of the nanosilica particles.

  The fluorine-containing alcohol used in the present invention has a terminal perfluoroalkyl group having 10 or less carbon atoms, and the fluorine-containing nanosilica obtained by coexisting organo nanosilica particles during the condensation reaction of the fluorine-containing alcohol and alkoxysilane. Composite particles can be stably dispersed in polar solvents such as water, alcohol, tetrahydrofuran, etc., and have excellent heat resistance at high temperatures such as 800 ° C. Specifically, the composite particle diameter can be increased or reduced in weight. It is decreasing. In addition, those having a perfluoroalkyl group having a carbon number of less than 8 do not generate perfluorooctanoic acid or the like even when released into the environment, which does not lead to environmental pollution.

As the fluorine-containing alcohol [I], for example, a general formula
C _n F _{2n + 1} (CH ₂ ) _d OH (II)
n: 1 to 10, preferably 1 to 6
d: 1-6, preferably 2
The polyfluoroalkyl alcohol represented by these is used.

Examples of the alkylene group A include —CH ₂ — group, —CH ₂ CH ₂ — group, and the like, and examples of the polyfluoroalkyl alcohol (perfluoroalkylalkyl alcohol) having such an alkylene group include 2,2,2-trimethyl. Fluoroethanol (CF ₃ CH ₂ 0H), 3,3,3-trifluoropropanol (CF ₃ CH ₂ CH ₂ OH), 2,2,3,3,3-pentafluoropropanol (CF ₃ CF ₂ CH ₂ 0H) ), 3,3,4,4,4-pentafluorobutanol (CF ₃ CF ₂ CH ₂ CH ₂ OH), 2,2,3,3,4,4,5,5,5-nonafluoropentanol ( CF ₃ CF ₂ CF ₂ CF ₂ CH ₂ 0H), 3,3,4,4,5,5,6,6,6-nonafluorohexanol (CF ₃ CF ₂ CF ₂ CF ₂ CH ₂ CH ₂ OH), 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanol (CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ CH ₂ CH ₂ OH) etc. Is exemplified.

The polyfluoroalkyl alcohol represented by the general formula [II] is described in, for example, Patent Document 2, and is synthesized through the following series of steps.
First, the general formula
C _n F _{2n + 1} (CF ₂ CF ₂ ) _b (CH ₂ CH ₂ ) _c I
A polyfluoroalkyl iodide represented by, for example,
CF ₃ (CH ₂ CH ₂ ) I
CF ₃ (CH ₂ CH ₂ ) ₂ I
C ₂ F ₅ (CH ₂ CH ₂ ) I
C ₂ F ₅ (CH ₂ CH ₂ ) ₂ I
C ₃ F ₇ (CH ₂ CH ₂ ) I
C ₃ F ₇ (CH ₂ CH ₂ ) ₂ I
C ₄ F ₉ (CH ₂ CH ₂ ) I
C ₄ F ₉ (CH ₂ CH ₂ ) ₂ I
C ₂ F ₅ (CF ₂ CF ₂ ) (CH ₂ CH ₂ ) I
C ₂ F ₅ (CF ₂ CF ₂ ) (CH ₂ CH ₂ ) ₂ I
C ₂ F ₅ (CF ₂ CF ₂ ) ₂ (CH ₂ CH ₂ ) I
C ₂ F ₅ (CF ₂ CF ₂ ) ₂ (CH ₂ CH ₂ ) ₂ I
C ₂ F ₅ (CF ₂ CF ₂ ) ₃ (CH ₂ CH ₂ ) I
C ₄ F ₉ (CF ₂ CF ₂ ) (CH ₂ CH ₂ ) I
C ₄ F ₉ (CF ₂ CF ₂ ) ₂ (CH ₂ CH ₂ ) I
C ₄ F ₉ (CF ₂ CF ₂ ) (CH ₂ CH ₂ ) ₂ I
C ₄ F ₉ (CF ₂ CF ₂ ) ₂ (CH ₂ CH ₂ ) ₂ I
C ₄ F ₉ (CF ₂ CF ₂ ) ₃ (CH ₂ CH ₂ ) I
Is reacted with N-methylformamide HCONH (CH ₃ ) to form a mixture of polyfluoroalkyl alcohol and its formate, and then hydrolyzed to it in the presence of an acid catalyst to give polyfluoroalkyl alcohol.
C _n F _{2n + 1} (CF ₂ CF ₂ ) _b (CH ₂ CH ₂ ) _c OH
To form.

  These fluorine-containing alcohol and alkoxysilane are reacted in the presence of an alkaline or acidic catalyst to form fluorine-containing nanocomposite particles.

The alkoxysilane has the general formula
(R ₁ O) _p Si (OR ₂ ) _q (R ₃ ) _r (III)
R _1, R _3: H, alkyl group or aryl group C ₁ -C ₆
R _2: an alkyl group or an aryl group of C ₁ -C ₆
However, R ₁ , R ₂ and R ₃ are not all aryl groups
p + q + r: 4 where q is not 0, for example, trimethoxysilane, triethoxysilane, trimethoxymethylsilane, triethoxymethylsilane, trimethoxyphenylsilane, triethoxyphenylsilane, tetramethoxysilane Tetraethoxysilane or the like is used.

  The reaction between these components may be an alkaline or acidic catalyst such as aqueous ammonia or an aqueous solution of an alkali metal or alkaline earth metal hydroxide such as sodium hydroxide, potassium hydroxide or calcium hydroxide, or hydrochloric acid or sulfuric acid. In the presence, the reaction is carried out at a temperature of about 0 to 100 ° C., preferably about 10 to 30 ° C., for about 0.5 to 48 hours, preferably about 1 to 10 hours.

  The amount of fluorine-containing alcohol in the obtained fluorine-containing nanocomposite particles is about 1 to 50 mol%, preferably about 5 to 30 mol%, and the composite particle diameter (measured by dynamic light scattering method) is about 30 to 200 nm.

  When such a fluorine-containing nanocomposite is produced, if a condensation reaction is carried out in the presence of organonanosilica particles in the reaction system, the fluorine-containing nanosilica composite as a condensate consisting of three components of fluorine-containing alcohol-alkoxysilane-nanosilica particles Particles can be produced.

  The nanosilica particles have an average particle size (measured by dynamic light scattering method) of 5 to 200 nm, preferably 10 to 100 nm, and a primary particle size of 40 nm or less, preferably 5 to 30 nm, more preferably 10 to A 20 nm organosilica sol is used. Actually, Nissan Chemical Industries product methanol silica sol, Snowtex IPA-ST (isopropyl alcohol dispersion), Snowtex EG-ST (ethylene glycol dispersion), Snowtex MEK-ST (methyl ethyl ketone dispersion), which are commercially available products, Snowtex MIBK-ST (methyl isobutyl ketone dispersion) or the like is used.

  Each of these components is about 1 to 99 parts by weight, preferably about 10 to 50 parts by weight of fluorine-containing alcohol, and about 1 to 99 parts by weight of alkoxysilane, preferably 100 parts by weight of nanosilica particles. About 10 to 50 parts by weight are used. When the proportion of the fluorinated alcohol used is less than this, the water / oil repellency becomes low. On the other hand, when it is used in a proportion larger than this, the dispersibility in the solvent becomes poor. Further, if the proportion of alkoxysilane used is less than this, the dispersibility in the solvent is deteriorated, whereas if it is used in a proportion higher than this, the water / oil repellency is lowered.

  Fluorine-containing nanosilica composite particles, which are reaction products, are considered to have a fluorine-containing alcohol bonded to the hydroxyl group on the surface of the nanosilica particles using a siloxane bond as a spacer. Therefore, the chemical and thermal stability of silica and fluorine Excellent water and oil repellency, antifouling properties, etc. are effectively demonstrated, and the actual glass surface treated with fluorine-containing nanosilica composite particles shows good water and oil repellency, and weight loss at 800 ° C The effect of reducing the amount is seen. In addition, the particle diameter of nanosilica composite particles and the variation thereof are also small. The nanosilica composite particles are formed as a reaction product of fluorine-containing alcohol and alkoxysilane and nanosilica particles, but other components can be mixed as long as the object of the present invention is not impaired.

  Next, the present invention will be described with reference to examples.

Example 1
CF ₃ (CF ₂ ) ₃ (CH ₂ ) ₂ OH [FA-4] 0.25 g was added to 30 ml of methanol and dissolved, and silica sol (Nissan Chemicals product methanol silica sol; containing 30 wt% nano silica, average) Particle size 11nm) 1.67g (0.50g as nano silica) and tetraethoxysilane (Tokyo Kasei product; density 0.93g / ml) 0.25ml are added, stirring with a magnetic stirrer, 0.25ml of 25wt% ammonia water is added, The reaction was performed for 5 hours.

  After completion of the reaction, methanol and aqueous ammonia were removed under reduced pressure using an evaporator, and the obtained powder was redispersed in about 20 ml of methanol overnight. The next day, centrifugation was performed using a centrifuge tube, the supernatant was discarded, and fresh methanol was added to perform rinsing. After performing this rinsing operation three times, the mouth of the centrifuge tube was covered with aluminum foil and placed in a 70 ° C. oven overnight. The next day, it was put in a vacuum dryer at 50 ° C. overnight and dried to obtain 0.582 g (yield 71%) of white powder.

  The particle size and variation of the obtained white powder fluorine-containing nanosilica composite were measured by a dynamic light scattering (DLS) measurement method at 25 ° C. for a solid content concentration of 1 g / L methanol dispersion. Further, thermogravimetric analysis (TGA) was performed before and after baking at 800 ° C. At that time, the heating rate was 10 ° C./min. Furthermore, the percentage of the weight reduced by firing relative to the initial weight was also calculated.

Furthermore, the dispersibility of the composite particles dispersed at a solid content concentration of 1% by weight in water [H ₂ O], methanol [MeOH], ethanol [EtOH], 1,2-dichloroethane [DCE] and tetrahydrofuran [THF] was visually confirmed. And evaluated according to the following evaluation criteria.
○: Dispersed uniformly, transparent dispersion
Δ: Slightly dispersed, dispersion is cloudy
×: Not dispersed but precipitated in the dispersion medium

Examples 2-5
In Example 1, 25 wt% aqueous ammonia was variously changed.

Examples 6-10
In Examples 1 to 5, CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ OH [FA-6; C ₂ F ₅ (CF ₂ CF ₂ ) ₂ (CH ₂ CH ₂ ) OH] is the same as the fluorinated alcohol. An amount (0.25 g) was used.

Examples 11-15
In Examples 1 to 5, CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ OH [FA-8; C ₂ F ₅ (CF ₂ CF ₂ ) ₃ (CH ₂ CH ₂ ) OH] is the same as the fluorinated alcohol. An amount (0.25 g) was used.

The amount of ammonia water, the recovered amount, the yield, and various measurement results in each of the above examples are shown in the following Table 1. The dispersibility evaluation is shown in Table 2.
The yield is calculated as follows, assuming that tetraalkoxysilane undergoes a self-condensation reaction to form a three-dimensional siloxane-bonded Si-O, and that a -O-Si-O- [SiO ₂ ] skeleton is generated. Obtained from the equation. When silica is not used, C = 0 is calculated.
Yield (%) = A / [B + C + (D × E × F / G)] × 100
A: Generated composite weight (g)
B: Fluorine-containing alcohol weight (g)
C: Silica weight (g)
D: Tetraalkoxysilane capacity (ml)
E: Tetraalkoxysilane density (g / ml)
F: SiO ₂ molar weight (g / mol) derived from tetraalkoxysilane
G: Tetraalkoxysilane molar weight (g / mol)

Table 1
Fluorine-containing nanosilica
aq, NH ₃ recovery Yield Composite particle size (nm) Weight reduction
Example (ml) (g) (%) Before firing After firing at 800 ° C. (%)
1 0.25 0.582 71 36.8 ± 9.9 39.0 ± 3.1 7
2 0.50 0.559 68 30.1 ± 7.3 39.5 ± 9.9 7
3 1.0 0.352 43 69.1 ± 13.9 45.3 ± 10.9 7
4 2.0 0.419 51 41.5 ± 10.2 42.6 ± 9.2 7
5 4.0 0.571 70 34.0 ± 7.6 139.8 ± 25.5 7
6 0.25 0.500 61 35.3 ± 8.3 53.3 ± 11.4 8
7 0.50 0.580 71 40.5 ± 11.3 40.5 ± 12.0 6
8 1.0 0.590 72 40.5 ± 13.0 62.3 ± 18.5 6
9 2.0 0.488 60 105.3 ± 19.0 97.5 ± 30.2 7
10 4.0 0.426 52 45.4 ± 13.2 60.9 ± 17.1 6
11 0.25 0.521 64 41.7 ± 13.7 81.7 ± 21.6 7
12 0.50 0.481 59 28.2 ± 6.0 32.2 ± 9.8 6
13 1.0 0.475 58 56.6 ± 11.5 53.7 ± 10.2 6
14 2.0 0.516 63 53.6 ± 11.4 55.1 ± 14.5 6
15 4.0 0.565 69 39.7 ± 9.2 35.4 ± 12.8 7

Table 2
Example H ₂ O MeOH EtOH DCE THF
1 △ ○ ○ ○ ○
2 ○ ○ ○ ○ ○
3 ○ ○ ○ ○ ○
4 ○ ○ ○ ○ ○
5 ○ ○ ○ ○ ○
6 ○ ○ ○ ○ ○
7 ○ ○ ○ ○ ○
8 △ ○ ○ ○ ○
9 ○ ○ ○ ○ ○
10 ○ ○ ○ ○ ○
11 ○ ○ ○ ○ ○
12 ○ ○ ○ ○ ○
13 ○ ○ ○ ○ ○
14 ○ ○ ○ ○ ○
15 ○ ○ ○ ○ ○

Reference Examples 1-3
In Examples 13-15, methanol silica sol was not used.

The amount of aqueous ammonia, the generated fluorine-containing nanocomposite particles, the recovered amount, the yield, and various measurement results in Reference Examples 1 to 3 are shown in Table 3 below. The dispersibility evaluation is shown in Table 4.
Table 3
Fluorine-containing nano
aq, NH ₃ recovery Yield Composite particle size (nm) Weight reduction
Reference example (ml) (g) (%) Before firing After firing at 800 ° C (%)
1 1.0 0.065 20 54.5 ± 12.0 16.6 ± 3.8 18
2 2.0 0.059 19 21.1 ± 6.0 26.4 ± 6.0 17
3 4.0 0.065 20 37.3 ± 8.1 49.6 ± 11.2 17

Table 4
Reference example H ₂ O MeOH EtOH DCE THF
1 ○ ○ ○ ○ ○
2 ○ ○ ○ ○ ○
3 △ ○ ○ ○ ○

Examples 21-35, Reference Examples 11-13
Dispersion of methanol in the fluorine-containing nanosilica composite particles before firing (Examples 21 to 35) and the fluorine-containing nanocomposite particles before firing (Reference Examples 11 to 13) obtained in Examples 1 to 15 and Reference Examples 1 to 3 The liquid (particle concentration 5g / L) is dipped into a glass preparation, dried at room temperature, and a 4μl droplet is gently brought into contact with n-dodecane or water on the surface of the resulting thin layer at room temperature. The contact angle (unit: °) of the obtained droplet was measured by a contact angle meter (DropMaster 300, manufactured by Kyowa Interface Chemical) by the θ / 2 method. The water was measured over time. The results obtained are shown in Table 5 below.
Table 5
Water (Elapsed time: minutes)
Example composite dodecane 0 5 10 15 20 25 30
Example 21 Example 1 35 21 10 0 0 0 0 0
〃 22 〃 2 7 22 17 15 13 11 10 7
〃 23 ３ 3 4 7 0 0 0 0 0 0
〃 24 〃 4 0 7 0 0 0 0 0 0
〃 25 ５ 5 0 0 0 0 0 0 0 0
〃 26 ６ 6 49 28 0 0 0 0 0 0
〃 27 〃 7 46 48 27 26 24 20 20 17
〃 28 〃 8 16 19 19 16 14 13 10 8
〃 29 〃 9 14 11 0 0 0 0 0 0
〃 30 〃 10 19 16 7 0 0 0 0 0
〃 31 〃 11 114 37 34 33 31 30 30 28
〃 32 〃 12 108 61 58 52 49 46 45 41
〃 33 〃 13 123 59 17 0 0 0 0 0
〃 34 〃 14 125 23 13 10 8 0 0 0
〃 35 〃 15 127 91 18 4 0 0 0 0

Reference Example 11 Reference Example 1 50 52 48 45 38 34 29 25
〃 12 〃 2 45 62 54 47 44 37 33 25
〃 13 ３ 3 43 35 29 26 22 18 14 9

Claims (3)

General formula
R _F -A-OH (I)
(Wherein R _F is a perfluoroalkyl group and A is an alkylene group) fluorinated nanosilica composite particles comprising a fluorinated alcohol and a condensation product of alkoxysilane and nanosilica particles. As the fluorine-containing alcohol represented by the general formula [I], the general formula
C _n F _{2n + 1} (CH ₂ ) _d OH (II)
The fluorine-containing nanosilica composite particle according to claim 1, wherein a polyfluoroalkyl alcohol represented by the formula (where n is an integer of 1 to 10 and d is an integer of 1 to 6) is used.   Fluorine-containing nanosilica composite particles, wherein the fluorine-containing alcohol [I] or [II] and alkoxysilane according to claim 1 or 2 are subjected to a condensation reaction in the presence of nanosilica particles using an alkaline or acidic catalyst. Manufacturing method.