JP7761471B2 - Fluorine-containing silane compound and surface modifier using the same - Google Patents

Description

The present invention relates to a novel fluorine-containing silane compound and a surface modifier using the same.

Fluorine-containing compounds have unique properties based on the properties of the carbon-fluorine bond, such as chemical resistance, water and oil repellency, stain resistance, low friction, and release properties, and are used as functional materials.
In particular, compositions containing a silane compound having a perfluoroalkyl group and a solvent can be applied to a substrate and dried to form a coating film exhibiting the above properties, and are therefore used as surface modifiers such as antifouling agents, water- and oil-repellent agents, etc. In particular, when imparting antifouling properties to substrates such as glass, the ability to remove droplets of oil and the like and abrasion resistance are required.

Conventionally, compounds having a long-chain perfluoroalkyl group having 8 or more carbon atoms have been used as fluorine-containing silane compounds that exhibit high surface modification performance (see, for example, Patent Document 1). However, compounds having a long-chain perfluoroalkyl group having 8 or more carbon atoms have problems such as their tendency to accumulate in the environment and living organisms.
Therefore, studies are being conducted to replace them with fluorine-containing compounds having a perfluoroalkyl group with six or fewer carbon atoms, which are considered to have low bioaccumulation potential. However, it is known that the smaller the carbon number of the perfluoroalkyl group, the poorer the surface modification performance becomes compared to compounds having a perfluoroalkyl group with eight or more carbon atoms.

Patent Document 2 discloses a fluorine-containing compound composed of a perfluoroalkyl group having six or fewer carbon atoms and exhibiting high surface modification performance, as well as a surface modifier using the compound. However, the inventors' investigations revealed that the abrasion resistance was insufficient, and further improvement was needed.

Patent No. 2800786 International Publication No. 2017/119371

The object of the present invention is to provide a novel fluorine-containing silane compound composed of a perfluoroalkyl group having six or fewer carbon atoms, which is considered to have low bioaccumulation potential, and which can form a coating film with excellent droplet removal properties and abrasion resistance, as well as a surface modifier using the same.

The inventors discovered that a surface modifier using the fluorine-containing silane compound shown below forms a coating film with excellent droplet removal properties and abrasion resistance, leading to the completion of the present invention.

That is, the present invention relates to the following.
[1] A fluorine-containing silane compound represented by the following general formula (1):
(In formula (1),
^Rf1 is a perfluoroalkyl group having 1 to 6 carbon atoms;
^Rf2 is a perfluoroalkylene group having 1 to 6 carbon atoms,
R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
m is an integer from 0 to 2,
n is an integer from 1 to 10,
X is a hydroxyl group, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group having 2 to 6 carbon atoms, or an isocyanate group;
Y is a hydrogen atom, a halogen atom, or an alkoxy group having 1 to 3 carbon atoms;
Z is a divalent hydrocarbon group having 1 to 10 carbon atoms.
[2] In the general formula (1), Rf ¹ is a linear perfluoroalkyl group having 1 to 6 carbon atoms, and Rf ² is a linear perfluoroalkylene group having 1 to 6 carbon atoms. Item [1] Fluorine-containing silane compound.
[3] In the general formula (1), n is an integer of 1 to 4. The fluorine-containing silane compound according to item [1] or [2].
[4] The fluorine-containing silane compound according to any one of items [1] to [3], wherein in the general formula (1), X is a halogen atom or an alkoxy group having 1 to 3 carbon atoms.
[5] The fluorine-containing silane compound according to any one of items [1] to [4], wherein Z is a —CH═CH— group in the general formula (1).
[6] A mixture of two or more of the fluorine-containing silane compounds according to any one of [1] to [5].
[7] A surface modifier comprising the fluorine-containing silane compound according to any one of items [1] to [5].

The present invention will be described in detail below.
In general formula (1), the ^Rf1 group is preferably a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms, more preferably a linear perfluoroalkyl group. This is because, although the ^Rf1 group may have a branched structure, a linear perfluoroalkyl group is more likely to exhibit high water and oil repellency.

In general formula (1), the ^Rf2 group is preferably a linear or branched perfluoroalkylene group having 1 to 6 carbon atoms, more preferably a linear perfluoroalkylene group. This is because, although the ^Rf2 group may have a branched structure, a linear perfluoroalkylene group is more likely to exhibit high water and oil repellency.
Among these, it is preferable that Rf ¹ is a linear perfluoroalkyl group having 4 to 6 carbon atoms, and Rf ² is a linear perfluoroalkylene group having 4 to 6 carbon atoms.

In general formula (1), R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In general formula (1), m is an integer from 0 to 2. Of these, it is preferable that m is 0.

In general formula (1), n is an integer from 1 to 10. From the perspective of ease of production, n is preferably 1 to 4.

In general formula (1), X represents a hydroxyl group, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group having 2 to 6 carbon atoms, or an isocyanate group. From the standpoint of ease of production and handling, it is preferable that X represents a halogen atom or an alkoxy group having 1 to 3 carbon atoms, and it is even more preferable that X represents a chlorine atom, a methoxy group, or an ethoxy group.

In general formula (1), Y is a hydrogen atom, a halogen atom, or an alkoxy group having 1 to 3 carbon atoms. It is particularly preferred that Y be a hydrogen atom, an iodine atom, or a methoxy group.

In general formula (1), Z is a divalent hydrocarbon group having 1 to 10 carbon atoms and does not contain a fluorine atom. Specific examples include saturated and unsaturated hydrocarbon groups such as -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH=CH-, and -C ₆ H ₄ -. Of these, the -CH=CH- group is preferred.

Specific structures of the Rf ¹ -Z-Rf ² - portion in general formula (1) include, but are not limited to, C ₂ F ₅ -CH=CH-C ₄ F ₈ -, C ₂ F ₅ -CH=CH-C ₆ F ₁₂ -, C ₄ F ₉ -CH=CH-C ₄ F ₈ -, C ₄ F ₉ -CH=CH-C ₆ F ₁₂ , C ₆ F ₁₃ -CH=CH-C ₄ F ₈ -, and C ₆ F ₁₃ -CH=CH-C ₆ F ₁₂ -.

The fluorine-containing silane compound of the present invention represented by general formula (1) can be obtained by the following method, but is not limited thereto.
The fluorine-containing silane compound of the present invention represented by general formula (1) can be produced using, as a starting material, a terminally iodinated fluoroalkyl compound represented by the following general formula (2): Fluoroalkyl compounds in which Z is a —CH═CH— group are known and are described in Patent Document 2 (WO 2017/119371).
Rf ¹ -Z-Rf ² -I (2)

A fluorine-containing silane compound in which Y is an iodine atom can be obtained by reacting a compound represented by the above general formula (2) with a compound represented by the following general formula (3) in the presence of a radical initiator. The iodine atom can be converted to a hydrogen atom, a halogen atom, or an alkoxy group having 1 to 3 carbon atoms, as necessary.
CH ₂ =CH-SiR _m X _3-m (3)
(In formula (3), R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
m is an integer from 0 to 2,
X is a hydroxyl group, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group having 2 to 6 carbon atoms, or an isocyanate group.

Specific examples of the compound represented by general formula (3) of the present invention include trichlorovinylsilane, vinyltrimethoxysilane, vinyltriethoxysilane, dichloromethylvinylsilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, chlorodimethylvinylsilane, dimethylmethoxyvinylsilane, dimethylethoxyvinylsilane, etc. Among these, trichlorovinylsilane, vinyltrimethoxysilane, and vinyltriethoxysilane are preferred.
The amount of compound (3) used in the production of the fluorine-containing silane compound represented by general formula (1) of the present invention is preferably 1 to 20 equivalents, more preferably 1 to 10 equivalents, and particularly preferably 2 to 10 equivalents, relative to the amount of compound (2) used in the reaction.

Specific examples of the radical initiator used in the production of the fluorine-containing silane compound represented by general formula (1) of the present invention include azo initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 2-(carbamoylazo)isobutyronitrile; peroxides such as benzoyl peroxide, di-t-butyl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxypivalate, and lauryl peroxide; persulfates such as potassium persulfate and ammonium persulfate; benzophenone derivatives, phosphine oxide derivatives, benzoketone derivatives, phenylthioether derivatives, azide derivatives, diazo derivatives, and disulfide derivatives. These polymerization initiators may be used alone or in combination of two or more.
The amount of the radical initiator used in the production of the fluorine-containing silane compound represented by general formula (1) of the present invention is preferably 0.001 to 10% by weight, more preferably 0.002 to 10% by weight, and particularly preferably 0.002 to 5% by weight, based on the total amount of compound (2) used in the reaction.

In the production of the fluorine-containing silane compound represented by general formula (1) of the present invention, a solvent may be used as needed. Examples of the solvent include aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and tetralin; aliphatic or alicyclic hydrocarbon solvents such as n-hexane, n-heptane, mineral spirits, and cyclohexane; halogenated solvents such as methyl chloride, methyl bromide, methyl iodide, methylene dichloride, chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene, and orthodichlorobenzene; trifluoromethylbenzene, 1,3-bis(trifluoromethyl)benzene, 1,4-bis(trifluoromethyl)benzene, and 1,1,1,2,2-pentafluoro-3,3-dichloropropane; Any solvent that is inert to the reaction can be used, including fluorine-based solvents such as hydrofluoroethers such as hexane, 1,1,2,2,3-pentafluoro-1,3-dichloropropane, pentafluorobutane, decafluoropentane, perfluorohexane, perfluorocyclohexane, perfluorodecalin, hexafluorobenzene, methyl nonafluorobutyl ether (HFE7100), ethyl nonafluorobutyl ether (HFE7200), and 1,1,1,2,3,4,4,5,5,5-decafluoro-3-methoxy-2-(trifluoromethyl)pentane (HFE7300). These solvents may be used alone or in combination of two or more.
The solvent can be appropriately selected depending on the compound to be subjected to the reaction, and a solvent may not be used.

The fluorine-containing silane compound represented by general formula (1) of the present invention can be purified by known methods, such as solvent extraction, decantation, filtration, concentration, distillation, etc., to obtain the desired fluorine-containing silane compound represented by general formula (1).

The fluorine-containing silane compound of the present invention represented by general formula (1) can be used alone or dissolved in a solvent as a surface modifier. The fluorine-containing silane compound may be used alone or in combination of two or more fluorine-containing silane compounds in any ratio.
In the surface modifier of the present invention containing a fluorine-containing silane compound and a solvent, the concentration of the fluorine-containing silane compound is preferably 0.001 to 50% by weight, more preferably 0.01 to 20% by weight.

In the surface modifier containing a fluorine-containing silane compound of the present invention, any solvent that is miscible with the fluorine-containing silane compound can be used. Examples include alcohols such as methanol, ethanol, and isopropyl alcohol; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); esters such as methyl acetate, ethyl acetate, and butyl acetate; hydrocarbons such as hexane, heptane, octane, benzene, toluene, and xylene; and ethers such as 1,2-dimethoxyethane, diglyme, 1,4-dioxane, diethyl ether, dibutyl ether, tert-butyl methyl ether, tetrahydrofuran, and diisopropyl ether. Fluorine-based organic solvents such as hydrofluorocarbons, perfluorocarbons, perfluoroethers, and hydrofluoroalkyl ethers can also be used. Specific examples include benzotrifluoride (α,α,α-trifluorotoluene), 1,3-bis(trifluoromethyl)benzene, pentafluorobenzene, hexafluorobenzene, 2H,3H-decafluoropentane (vertrell), tetradecafluorohexane, octadecafluorooctane, dodecafluorocyclohexane, 1,3-bis(trifluoromethyl)decafluorocyclohexane, nonafluorobutyl methyl ether (isomer mixture), and nonafluorobutyl ethyl ether (isomer mixture). Among these, alcohols such as ethanol and isopropyl alcohol, hydrocarbons such as heptane, octane, and toluene, and fluorine-containing organic solvents such as 1,3-bis(trifluoromethyl)benzene and nonafluorobutyl ethyl ether (isomer mixture) are preferred because they have high solubility for the fluorine-containing silane compound (1) and also provide suitable coating properties and drying times for the surface modifier. These organic solvents may be used alone or in combination in any ratio.

An acid catalyst may be added to the surface modification composition of the present invention to facilitate the surface treatment. The acid catalyst may be either an inorganic or organic acid. Examples of inorganic acids include hydrohalic acids such as hydrochloric acid, hydrobromic acid, and hydroiodic acid; inorganic oxoacids such as sulfuric acid, nitric acid, and perchloric acid; organic carboxylic acids such as formic acid, acetic acid, propionic acid, and oxalic acid; and organic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, 2-propanesulfonic acid, butanesulfonic acid, 2-butanesulfonic acid, pentanesulfonic acid, trifluoromethanesulfonic acid, 2-hydroxyethane-1-sulfonic acid (isethionic acid), allylsulfonic acid, 1,3-propanedisulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, m-xylene-4-sulfonic acid, p-xylene-2-sulfonic acid, 2-sulfobenzoic acid, 5-sulfosalicylic acid, and p-phenolsulfonic acid. Among these, acetic acid, methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, or p-toluenesulfonic acid is preferred from the viewpoints of economy, safety, ease of handling, and the ability to achieve high-quality surface modification, and methanesulfonic acid, benzenesulfonic acid, or p-toluenesulfonic acid is more preferred.
The concentration of the acid catalyst in the surface modification composition of the present invention is preferably 0.0001% by weight to 50% by weight, more preferably 0.01% by weight to 20% by weight, based on the total amount of the surface modification composition, from the viewpoints of economy, stability of the composition (pot life), and uniformity of the film.

The surface modification composition of the present invention may contain a silane additive having another surface modification effect, which is a functional silane that has a bonding effect to the solid surface and the fluorine-containing silane compound (1) of the present invention.
Specific examples of the silane additive include alkylalkoxysilanes such as trimethoxymethylsilane, triethoxymethylsilane, dimethoxydimethylsilane, diethoxydimethylsilane, trimethoxyoctylsilane, and triethoxyoctylsilane; disilazanes such as hexamethyldisilazane and tetramethyldisilazane; halogenated silanes such as chlorotrimethylsilane, dichlorodimethylsilane, trichlorooctylsilane, chlorodimethyloctylsilane, chlorodimethyloctadecylsilane, trichlorooctadecylsilane, and silicon tetrachloride; tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane; and peralkoxyoligosiloxanes such as hexamethoxydisiloxane and hexaethoxydisiloxane.

If necessary, the surface modification composition of the present invention may also contain an amine-based neutralizing agent such as triethylamine, triethanolamine, tris(2-hydroxyethyl)amine, or morpholine; various surfactants, such as ionic and nonionic surfactants, that improve the wettability of the composition; and silicone oil or silicone varnish that further improves lubricity. These can be used in a proportion of approximately 0.001 to 300% by weight relative to the weight of the fluorine-containing silane compound (1) in the surface modification composition of the present invention.

Substrates can be treated with the surface modifier of the present invention by any method commonly used for surface modification with fluorine-containing surface modifiers, such as immersion, dip coating, spraying, pouring, spin coating, aerosol spraying, brush coating, coating with an impregnated cloth, vacuum deposition, sputtering, or CVD. From the standpoints of uniformity of surface modification, high water and oil repellency, and economy, immersion, dip coating, spin coating, brush coating, or coating with an impregnated cloth is preferred.

After applying the surface modifier of the present invention, if necessary, additional steps such as annealing under non-heating conditions, humidity-controlled conditions, or heated conditions, or cleaning may be added. Alternatively, the surface treatment agent may be applied to the substrate surface and then simply left to stand.

Substrates that can be treated with the surface modifier of the present invention include, but are not limited to, glass, silicon dioxide materials, metals, fibers, leather, cloth products, paper, plastics, and the like. In particular, fluorine-containing silane compounds exhibit bonding properties with hydroxyl groups, and therefore exhibit high durability as surface modifiers when used to treat substrates such as glass, silicon dioxide materials, metals, and cellulose. Specific examples include inorganic glass substrates such as quartz glass, soda glass, lead glass, borosilicate glass, and phosphate glass; silicon dioxide substrates such as single-crystal quartz, polycrystalline quartz, and silica gel; aluminosilicate substrates such as zeolite, mullite, mica, and clay minerals; metal oxide substrates such as alumina (aluminum oxide), titania (titanium oxide), zirconia (zirconium oxide), indium tin oxide, and indium zinc oxide; double oxide substrates such as spinel and iron ferrite; and metal substrates such as aluminum, titanium, iron, manganese, vanadium, nickel, chromium, copper, zinc, silicon, germanium, and alloys thereof.

The surface modifier containing the fluorine-containing silane compound of the present invention can be used as an antifouling agent, lubricant, water and oil repellent, rust inhibitor, water resistance agent, stripping agent, mold release agent, oil barrier agent, flux creep-up inhibitor, etc.

By using the fluorine-containing silane compound represented by general formula (1) of the present invention, a surface modifier with excellent droplet removal properties and abrasion resistance can be provided, using an active ingredient composed of a perfluoroalkyl group having six or fewer carbon atoms, which is considered to have low bioaccumulation potential.

The following are examples of the present invention, but the present invention is not limited to these examples.

The following equipment was used for the analysis:
< ^1H -NMR, ^19F -NMR>
Apparatus: Bruker AVANCE II 400
Internal standard: tetramethylsilane, trifluoromethylbenzene Solvent: chloroform-d

<GC-MS>
Apparatus: Shimadzu GCMS-QP2010Ultra
Column: GL Sciences TC-1

<Contact angle measurement>
Equipment: Contact angle meter DMs-401 manufactured by Kyowa Interface Science
Static contact angle measurement: Droplet volume 2 μL, analyzed by the θ/2 method. Sliding angle measurement: Droplet volume 20 μL, analyzed by the tangent method.

<Friction test>
Equipment: Rubbing tester IMC-1507 (Imoto Manufacturing Co., Ltd.)

Example 1
A 15 ml pressure-resistant test tube was charged with 2.50 g of 1,1,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11,11,12,12,13,13,14,14,14-pentacosafluoro-1-iodo-7-tetradecene (Tosoh Finechem, 3.24 mmol), 1.44 g of vinyltrimethoxysilane (Tokyo Chemical Industry, 9.71 mmol), and 21 mg of 2,2'-azobis(isobutyronitrile) (AIBN) (Fujifilm Wako Pure Chemical Industries, Ltd., 0.13 mmol), sealed, and then purged with nitrogen. The mixture was then reacted at 75 °C for 12 hours, cooled, and concentrated under reduced pressure at 30 °C and 0.1 kPa to obtain 3.44 g of fluorine-containing silane compound (4). The yield was 87% (weight equivalent, the same applies below).

The analytical results of the product are shown below.
Analysis by GC-MS revealed that the component with n=1 accounted for 8%, the component with n=2 accounted for 84%, and the component with n=3 accounted for 8%.
¹ H-NMR (solvent: deuterated chloroform, internal standard: tetramethylsilane) δ (ppm): 6.48 (m, C ₆ F ₁₃ CH═CH C ₆ F ₁₂ ), 3.67 (m, O CH ₃ ), 3.41-3.21 (m, CH ₂ I), 2.89-1.91 (m, CH ₂ ), 2.00 (m, CH ₂ CF ₂ ).
¹⁹ F-NMR (solvent: deuterated chloroform, internal standard: trifluoromethylbenzene) δ (ppm): -81.33 (t, 3F, CF ₃ ), -113.21 (m, 4F, CF ₂ CH ), -115.25 (m, 2F, CF ₂ CH ₂ ), -122.12 (m, 6F, CF ₂ CF ₂ CF ₂ ), -123.36 (m, 2F, CF ₂ ), -123.88 (m, 4F, CF ₂ CF ₂ ), -124.21 (m, 2F, CF ₂ ), -126.69 (m, 2F, CF ₂ )

Example 2
A 15 ml pressure-resistant test tube was charged with 2.50 g of 1,1,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11,11,12,12,13,13,14,14,14-pentacosafluoro-1-iodo-7-tetradecene (Tosoh Finechem, 3.24 mmol), 1.57 g of trichlorovinylsilane (Tokyo Chemical Industry, 9.71 mol), and 21 mg of 2,2'-azobis(isobutyronitrile) (AIBN) (Fujifilm Wako Pure Chemical Industries, Ltd., 0.13 mmol), sealed, and the inside was purged with nitrogen. The mixture was then reacted at 75 ° C for 12 hours, cooled, and concentrated under reduced pressure at 30 ° C and 0.1 kPa to obtain 3.57 g of fluorine-containing silane compound (5). The yield was 86%.

The analytical results of the product are shown below.
Analysis by GC-MS revealed that the component with n=1 accounted for 3%, the component with n=2 accounted for 86%, and the component with n=3 accounted for 11%.
¹ H-NMR (solvent: deuterated chloroform, internal standard: tetramethylsilane) δ (ppm): 6.49 (m, C ₆ F ₁₃ CH═CH C ₆ F ₁₂ ), 3.67 (m, O CH ₃ ), 3.58-3.21 (m, CH ₂ I), 2.61-1.80 (m, CH ₂ ), 2.00 (m, CH ₂ CF ₂ ).
¹⁹ F-NMR (solvent: deuterated chloroform, internal standard: trifluoromethylbenzene) δ (ppm): -81.52 (t, 3F, CF ₃ ), -108.94-115.02 (m, 6F, CF ₂ ), -122.08 (m, 4F, CF ₂ CF ₂ ), -123.42 (m, 4F, CF ₂ CF ₂ ), -124.80 (m, 2F, CF ₂ ), -126.40 (m, 2F, CF ₂ ).

Comparative Example 1
A 15 ml pressure-resistant test tube was charged with 1.50 g of tridecafluoro-1-iodohexane (Tokyo Chemical Industry Co., Ltd., 3.36 mmol), 1.50 g of vinyltrimethoxysilane (10.1 mmol), and 22 mg of 2,2'-azobis(isobutyronitrile) (AIBN) (0.13 mol). The tube was sealed and then purged with nitrogen. The reaction mixture was then allowed to react at 75°C for 12 hours, cooled, and concentrated under reduced pressure at 30°C and 0.1 kPa to obtain 2.59 g of fluorine-containing silane compound (6). The yield was 86%.

The analytical results of the product are shown below.
Analysis by GC-MS revealed that the component with n=1 accounted for 12%, the component with n=2 accounted for 82%, and the component with n=3 accounted for 6%.
¹ H-NMR (solvent: deuterated chloroform, internal standard: tetramethylsilane) δ (ppm): 3.68-3.61 _{(m, OCH 3 ), 3.48-3.20 (m, CH 2 I), 2.51-1.66 (m, CH 2} ) , _{2.01 (} m, CH ₂ CF ₂ )
¹⁹ F-NMR (solvent: deuterated chloroform, internal standard: trifluoromethylbenzene) δ (ppm): -81.41 (t, 3F, CF ₃ ), -112.48--116.44 (m, 2F, CF ₂ ), -122.28 (m, 2F, CF ₂ ), -123.39 (m, 2F, CF ₂ ), -124.22 (m, 2F, CF ₂ ), -126.68 (m, 2F, CF ₂ ).

Example 3
A surface modifier was prepared containing 0.1 wt% of the fluorine-containing silane compound (4) obtained in Example 1 and 99.9 wt% of ethyl nonafluorobutyl ether (manufactured by 3M, product name Novec 7200) as a solvent. Using this surface modifier, the surface modification performance was evaluated by the following method.

Surface Treatment A slide glass (manufactured by AS ONE, 25 mm × 75 mm × 1 mm thick) was immersed in the above-mentioned surface modifier, pulled out at a speed of approximately 4 mm/sec to dip coat it, and then left to stand in the air at room temperature for 24 hours to perform surface modification.

Contact Angle Measurement The static contact angle and sliding angle of the surface-treated slide glass were measured for pure water and oleic acid, respectively.
Here, the static contact angle was measured to quantify wettability. When a droplet is brought into contact with a solid surface and deposited, the angle between the droplet and the sample surface is taken as the contact angle θ. The larger the static contact angle, the better the water and oil repellency.
The sliding angle was also measured to quantify the droplet removability. A droplet was placed on a horizontal solid surface, and the solid sample was gradually tilted. The tilt angle at which the end point of the droplet moved 0.3 mm was taken as the sliding angle. A smaller sliding angle indicates better droplet removability.

Friction Test Kimwipes (manufactured by Nippon Paper Crecia) were attached to a friction tester, and the surface of the surface-treated glass was rubbed 20,000 times with a load of 200 g at a speed of 60 mm x 40 reciprocations/minute, and then the contact angle was measured in the same manner as above.
The results are shown in Table 1. In the following Examples and Comparative Examples, the same formulations as those shown in the above-mentioned method for evaluating surface modification performance were used.

Example 4
The surface modification performance was evaluated in the same manner as in Example 3, except that isopropanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as the solvent instead of ethyl nonafluorobutyl ether. The results are shown in Table 1.

Example 5
The surface modification performance was evaluated in the same manner as in Example 3, except that fluorine-containing silane compound (5) was used instead of fluorine-containing silane compound (4). The results are shown in Table 1.

Comparative Example 2
The surface modification performance was evaluated in the same manner as in Example 3, except that fluorine-containing silane compound (6) was used instead of fluorine-containing silane compound (4). The results are shown in Table 1.

Comparative Example 3
In Example 3, the surface modification performance was evaluated in the same manner as in Example 3, except that 3,3,4,4,5,5,6,6,7,7,8,8,11,11,12,12,13,13,14,14,15,15,16,16,16-pentacosafluoro-9-hexadecen-1-yltrimethoxysilane (7) (manufactured by Tosoh Finechem Co., Ltd.) was used instead of the fluorine-containing silane compound (4). The results are shown in Table 1.

The results in Table 1 show that the surface modifier containing the fluorine-containing silane compound of the present invention provides excellent water and oil repellency to the substrate. Furthermore, compared with the fluorine-containing silane compound (6) having a simple _{perfluoroalkyl} group ( _C6F13 group) and the compound (7) having only one silyl group, the sliding angle of pure water and oleic acid is small, providing excellent droplet removal properties.
Furthermore, in contact angle measurements after friction tests, the static contact angles with pure water and oleic acid were larger than those of fluorine-containing silane compound (6) having a simple perfluoroalkyl group (C ₆ F ₁₃ group) and compound (7) having only one silyl group, while the sliding angles were equal to or lower than those of the compound (6), indicating that the surface modifier containing the fluorine-containing silane compound of the present invention exhibits excellent wear resistance.
Therefore, it is useful as a surface modifier such as an antifouling agent for automobile glass, touch panels, lenses, etc., a water and oil repellent, a rust inhibitor, a water resistance agent, a stripping agent, a mold release agent, an oil barrier agent, and a flux creep-up inhibitor.

The fluorine-containing silane compound of the present invention and compositions containing it are composed of perfluoroalkyl groups having six or fewer carbon atoms, which are considered to have low bioaccumulation potential, and can be used as a surface modifier capable of forming a coating film with excellent droplet removal properties and abrasion resistance.

Claims (4)

A mixture containing two or more fluorine-containing silane compounds represented by the following general formula (1):
(In formula (1),
^Rf1 is a perfluoroalkyl group having 1 to 6 carbon atoms;
^Rf2 is a perfluoroalkylene group having 1 to 6 carbon atoms,
R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
m is an integer from 0 to 2,
n is 2 or 3 ;
X is a hydroxyl group, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group having 2 to 6 carbon atoms, or an isocyanate group;
Y is a hydrogen atom, a halogen atom, or an alkoxy group having 1 to 3 carbon atoms;
Z is a —CH═CH— group . 2. The mixture containing two or more kinds of fluorine-containing silane compounds according to claim 1, wherein, in the general formula (1), Rf ¹ is a linear perfluoroalkyl group having 1 to 6 carbon atoms, and Rf ² is a linear perfluoroalkylene group having 1 to 6 carbon atoms. 3. A mixture comprising two or more kinds of fluorine-containing silane compounds according to claim 1 or claim 2 , wherein, in said general formula (1), X is a halogen atom or an alkoxy group having 1 to 3 carbon atoms. A surface modifier comprising a mixture containing two or more of the fluorine-containing silane compounds according to any one of claims 1 to 3 .