JPH078900A - Production of high water-repellent material - Google Patents

Abstract

PURPOSE:To effectively execute the removal of water drops and the prevention of soiling on the surface of a substrate by applying a hydrolysate of a silane based compound expressed by a specific general formula on the surface of the substrate such as glass and drying by heating to firmly combine a water- repellent material with the surface of the substrate. CONSTITUTION:A film of the high water-repellent material is formed by applying the hydrolysate of the (trifluoromethyl) silane based compound expressed by the general formula, (F3C)m(CF2-n)nSiX4-n or (F3C)nSiX4-n, on the surface of the substrate such as metals, glasses or plastics. In the formula, each of (m) and (n) is integer 1-3, X is a halogen atom or a <=5C alhoxyl group. And when a substrate containing on metal oxide is used, an oxide layer of silicon or a metal is previously formed on the surface and the hydrolysate of the (trifluoromethyl) silane compound is applied thereon and dried by heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing water drops from glass, plastics, etc., and for preventing contamination.

[0002]

2. Description of the Related Art Conventionally, for removing water droplets from various materials such as metal, glass and plastic and preventing contamination, for example, a method of applying an aqueous solution of alkali alkyl siliconate has been proposed in Japanese Patent Publication No. 53-18345. However, since it is basic, there is a problem in hygiene and the water repellent effect is not sufficient. Furthermore, in recent years, it has been possible to develop not only water repellency but also oil repellency and antifouling property by forming a composition having a structure in which a perfluoroalkyl group is bonded to a silicon atom with a silicone-based compound having no alkali component, JP-A-3
-265581, JP-A-4-89877, JP-A4-1
32637 and the like.

[0003]

The water repellent group shown above is schematically represented by the following formula from its molecular structure.

[Chemical 1] (In the formula, m is an integer and r is an integer of 1 to _3. ) Here, a hydrocarbon chain length of C ₂ or more is used for the sake of simplicity of synthesis.

These are also reported by Zisman et al. (Journal of Physical Chem).
Istry, 66, 740 (1962)),
The perfluoroalkyl chain length is 6 or more in order to prevent the electric repulsion generated between —CF ₂ —CH ₂ — from reaching the —CF ₃ group at the end of the perfluoroalkyl group.

Generally, the critical surface tension (γ _c ) is proposed in the above-mentioned documents as an index showing the magnitude of the effect of water repellency, and the smaller this γ _{c, the} higher the water repellency. When γ _{c of} each functional group is compared, it is as shown in Table 1, and it is understood that a high degree of water repellency can be exhibited by laying CF ₃ groups on the surface. (Interscience Pub. 7
11 (1962))

[0006]

[Table 1]

In the conventional example shown in the schematic diagram of Chemical formula 1, a high degree of water repellency cannot be realized unless a CF ₃ group having a small γ _c value is arranged at the end of a long side chain. There is a problem that it needs to be controlled.

The object of the present invention is to solve the above-mentioned conventional problems.
Solve the problem, γ_cCF with small value ₃The surface of the water repellent layer
Easy to place, and like glass or plastic
It manufactures highly water-repellent materials that are firmly bonded to the base material.
is there.

[0009]

Means for Solving the Problems] The present invention has been made in order to achieve the object described above, the substrate surface, the general formula _{(F 3 C) m (CF} 3-n) n Si X 4-n , Or (F ₃
C) A hydrolyzate of a silane-based compound represented by _n SiX _4-n (m and n represent integers of 1 to 3, and X represents a halogen atom or an alkoxy group having 5 or less carbon atoms) is applied. Then, it is dried by heating to produce a highly water repellent material. Furthermore, for a base material that does not contain a metal oxide such as plastic, after coating the surface with an oxide of silicon or a metal, a hydrolyzate of the above (trifluoromethyl) silane compound is applied,
It is heated and dried.

The (trifluoromethyl) silane compound used as the water repellent of the present invention has a C atom directly attached to the silicon atom.
The shortest C in which the F ₃ group does not contain a bond or a C-H bond
It has a structure in which it is bonded via an F group. On the other hand, in order for this compound to form a film, a hydrolyzable group X to which the compounds bind to each other is required. Increasing the number of the hydrolyzable groups X improves the strength of the film, but deteriorates the orientation of the compound molecules. When the number of X is reduced, the orientation of the compound molecules is improved, but the film strength is reduced.

The hydrolyzable group X is preferably a halogen atom or an alkoxy group having 5 or less carbon atoms such as methoxy and ethoxy because it is easily hydrolyzed. Specific examples of the compound having a halogen atom as the hydrolysis group are as follows.

[Chemical 2]

[Chemical 3]

[Chemical 4]

[Chemical 5]

[Chemical 6]

[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

Compounds in which the hydrolyzable group is an alkoxy group are exemplified below.

[Chemical 12]

[Chemical 13]

[Chemical 14]

[Chemical 15]

[Chemical 16]

[Chemical 17]

[Chemical 18]

[Chemical 19]

[Chemical 20]

[Chemical 21]

Used in the present invention (trifluoromethyl)
Among silane-based compounds, trichloro (trifluoromethyl) silane F ₃ C-Si Cl ₃ (CA having a highly reactive chloro atom as a hydrolyzing group and having a small hydrophobic group
S Registry Number: 109111-29-7)
And dechlorobis (trifluoromethyl) silane (F
₃ C) ₂ Si Cl ₂ (CAS Registry Num
ber: 422-96-8) is preferred. These compounds are J
individual of Organometallic
As described in Chemistry, 316 (1986) 41-50, it can be easily synthesized by a known method.

Next, water is added to the above compound to hydrolyze it. Then, the hydrolyzate solution is applied to the base material, but it can be applied directly to a base material containing silicon or an oxide of an alkali metal such as glass.
However, since a substrate such as plastic does not contain a metal oxide, a silicon or metal oxide layer must be formed on the surface of the substrate and then applied.

The shape of the substrate is not limited to a flat plate shape, a lens-like curved surface, an embossed random texture, or the like. However, the surface of the base material must be washed beforehand with detergent and pure water to remove oil and fat components and other stains. When the base material is plastic, it is also effective to use an organic solvent that does not attack the plastic or perform plasma treatment.

In the case of using plastic as a base material, as a method for forming an oxide layer of metal or the like, a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method or an ion plating method, which is less likely to cause thermal deformation, or It is convenient to employ a chemical vapor deposition method such as plasma CVD. The oxide used here contains one or more of silicon, aluminum, magnesium, zirconium, titanium, tin, indium, tungsten, zinc, nickel and tantalum. The oxide layer of a metal or the like to be formed may be a single layer or a multi-layer, but the silicon oxide SiO 2 is the outermost layer in order to exhibit high adhesion.
It is preferable to form with _x (x = 1 to 2).

Regarding the thickness of the oxide layer, the thicker it is, the more excellent the scratch resistance is. However, for example, when the polycarbonate is coated by the vacuum deposition method, if it is too thin, the surface of the plastic can be completely and uniformly coated. No
Also, if it is too thick, cracks or delamination between coating layers occur, so 0.005-5% for a single layer using silicon oxide.
It is 0 μm, and in the case of a multilayer structure, it is in the range of 0.01 to 100 μm.

The method of applying the hydrolyzate solution directly to the substrate or to the substrate having the oxide layer of silicon or metal formed by the above-mentioned method includes simple brush coating, dipping method and spin coating method. , A spray method or the like can be adopted. At this time, in order to apply the hydrolyzate solution thinly and uniformly, this is appropriately solvent (for example,
Dilute with water, ethanol, methanol, benzene, hexane, toluene, etc.) before use.

Regarding the coating film thickness of the hydrolyzate, it is considered that the performance will be exhibited if it is a monomolecular film or more, but practically it is applied to about 0.1 to 10 μm. Dry fixing is performed to strengthen and accelerate the curing of the coating film and the bond between the substrate and the coating film. This is performed by heat drying or reduced pressure drying with slight heating, but since a large amount of the solvent component remains immediately after coating, it is air dried (for example, when ethanol is used, it is about 1 hour at room temperature) before the drying step. May be done.

This heat-drying step must be carried out below the heat-resistant temperature of the substrate when the substrate is poor in heat resistance such as plastic. For example, when polycarbonate is used as the base material, the treatment is performed at 110 ° C. for about 10 minutes, but in the case of polyethylene, it is at least 1 at 40 ° C.
It takes day and night. The hydrolyzate used in the present invention can be sufficiently fixed at the relatively low temperature as described above, which is also a feature of the present invention.

[0021]

In the compound used in the present invention, only the --CF ₃ group having a small γ _c value is bonded to the silicon atom so that it appears on the surface, and therefore it is not necessary to consider the orientation of the hydrophobic group. It is also considered that the compounds cause a polycondensation reaction to increase the strength of the coating film, react with the coating film and the silicon oxide or metal oxide contained in the substrate, and firmly bond with each other. The concept of the above operation is shown in the following chemical formula 22.

[Chemical formula 22]

Example 1 A slide glass was used as a substrate, first washed with methanol, and then washed with acid and washed with distilled water. On the other hand, ethanol: water = 90: 10
10% by weight of F ₃ C-Si CL ₃ as a water repellent in the solvent of
It melt | dissolved and produced the hydrolyzate solution. The glass treated as described above was dipped in this hydrolyzate solution, pulled up at 60 cm / min, air-dried at room temperature for 10 minutes, and then heat-treated at 110 ° C. for 1 hour to prepare a test piece.

(Example 2) (F ₃ C) ₂ S as a water repellent
except for using i Cl ₂ was performed in the same manner as in Example 1. (Example 3) Ethanol: water = pH 2 adjusted with acetic acid = water
90% solvent, F ₃ C-Si (OC) as water repellent
10% by weight of H ₃ ) ₃ was dissolved to prepare a hydrolyzate solution. Other than that was performed like Example 1.

(Comparative Example 1) Shin-Etsu Chemical Co., Ltd. as a water repellent
Ltd. _{KBM-7803 (F 3 C (} CF 2) 7 CH 2 CH 2 S
Example 3 was repeated except that i (OCH ₃ ) ₃ ) was used. (Comparative Example 2) KBM-7 manufactured by Shin-Etsu Chemical Co., Ltd. as a water repellent
_{103 (F 3 C- CH 2 CH} 2 Si (OCH 3) 3) other was used, was the same as in Example 3.

The water repellency of the test pieces obtained in the above Examples and Comparative Examples was evaluated. That is, the film-formed glass is set upright, and about 3 cc of water is sprayed with a mist, and if the droplet remains on the glass, it is judged as bad (x), and if the droplet falls by its own weight and does not remain (good). did. The results are shown in Table 2, and it was found that the examples of the present invention were excellent in water repellency.

[0026]

[Table 2]

(Example 4) The substrate has a width of 40 mm and a length of 5
A polycarbonate plate having a thickness of 0 mm and a thickness of 2 mm was used.
A metal oxide layer was formed on the surface of this polycarbonate plate using a vacuum vapor deposition device. In this apparatus, the evaporation material is heated by an electron beam heating method using a 2 kW triple E-type electron gun (model name: 980-7104) manufactured by Nichiden Anelva Co., Ltd. First, place the polycarbonate plate above the electron gun 3
After mounting at a position of 0 cm, the gas was evacuated to 1 × 10 ⁻⁵ Torr or less, and the pellet for high-purity zirconium oxide vapor deposition was heated by electron beam heating to 3 × 10 ^{−5 to} 5 × 10 ^−5.
It was treated with Torr for 40 seconds to form a 0.03 μm zirconium oxide film. Further on, 1 × 10 ^-5 To
Evacuate below rr and heat the special grade silicon dioxide vapor deposition pellets by electron beam heating to 3 × 10 ^{−5 to} 5 × 1.
It was treated with 0 ^-5 Torr for 40 seconds to form a 0.03 μm silicon dioxide layer.

Next, 10 wt% of F ₃ C-Si CL ₃ as a water repellent was dissolved in a solvent of ethanol: water = 90: 10 to prepare a hydrolyzate solution. Immerse the above treated polycarbonate plate in this hydrolyzate solution and
/ Minute, and air-dry at room temperature for 10 minutes, then 1
A heat treatment was performed at 00 ° C. for 1 hour to prepare a test piece.

Example 5 The second layer of the metal oxide layer of Example 4 was sputtered. That is, the polycarbonate plate coated with the zirconium oxide layer in Example 4 was replaced with a sputtering device (manufactured by Nippon Vacuum Technology Co., Ltd., model: SH-).
100) and titanium dioxide was used as a target. After depressurizing the inside of the vacuum chamber to 5 × 10 ⁻⁶ Torr, high-purity argon gas was introduced, and sputtering was performed at 5 × 10 ⁻³ Torr with a high-frequency input power of 100 W for 10 minutes. When the thickness of the titanium dioxide layer was measured by a stylus method (manufactured by Sloan, model: Dektak3030) from the step provided at the end, it was 0.10 μm. Others are Example 4
I went the same way.

(Example 6) Polymethylmethacrylate was used as the substrate, and the other operations were performed in the same manner as in Example 4. Except for using (Example 7) as a water repellent agent _{(F 3 C) 2 Si Cl} 2, was performed in the same manner as in Example 4. (Example 8) Ethanol: water = pH 2 adjusted with acetic acid = water
90% solvent, F ₃ C-Si (OC) as water repellent
10% by weight of H ₃ ) ₃ was dissolved to prepare a hydrolyzate solution. Other than that was performed like Example 4.

Example 9 In a solvent of ethanol: water = 90: 10 adjusted to pH 2 with acetic acid, F ₃ C was used as a water repellent.
- Si a (OCH _{3) 3} were dissolved 10 wt%, to prepare a hydrolyzate solution. Other than that was performed like Example 5. Ethanol was adjusted to pH2 (Example 10) acetic acid: water = 90: 10 solvent, as water repellents F ₃ C-Si (O
10% by weight of CH ₃ ) ₃ was dissolved to prepare a hydrolyzate solution. Other than that was performed like Example 6.

(Comparative Example 3) A polycarbonate plate not treated with a metal oxide layer was used as a substrate. On the other hand, p with acetic acid
In a solvent of ethanol: water = 90: 10 adjusted to H2,
As a water repellent, Shin-Etsu Chemical Co., Ltd. KBM-7803 (F ₃
10 wt% of C (CF ₂ ) ₇ CH ₂ CH ₂ Si (OCH ₃ ) ₃ )
%, The above polycarbonate plate was immersed in the solution, pulled up at 60 cm / min, air-dried at room temperature for 10 minutes, and then heat-treated at 100 ° C. for 1 hour to prepare a test piece.

Comparative Example 4 A polycarbonate plate coated with an oxide layer in the same manner as in Example 4 was used as the substrate, and the water repellent treatment was performed in the same manner as in Comparative Example 3.

The above Examples 4 to 10 and Comparative Examples 3 to 4
The water repellency and the adhesiveness of the coating film were evaluated for the test piece obtained in 1. The evaluation method of water repellency is the same as in Examples 1 to 3 and Comparative Examples 1 and 2. Regarding the adhesion of the coating film, the case where peeling occurred was judged as bad (×) by the cellophane tape peeling test defined in JIS K 5400. 10
The case where 0/100 remained was rated as good (⊚). Table 3 shows the results, and it can be seen that the examples are excellent in both water repellency and adhesion of the coating film.

[0035]

[Table 3]

[0036]

According to the present invention, as understood from the examples, it becomes possible to easily carry out a high-level water repellent treatment without adjusting the molecular orientation and the like. Further, since the method of the present invention enables the water repellent treatment at a relatively low temperature, it can be applied to plastics having a low heat resistant temperature without anxiety and has an advantage that the adhesion of the treatment layer is extremely high. Therefore, transparent glass or plastic that has been subjected to this water repellent treatment is expected to be a useful material in the field of vehicles and the like.

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Claims (2)

[Claims] To 1. A substrate surface, the general formula _{(F 3 C) m (CF} 3-n) n Si X 4-n or (F _3,
C) A hydrolyzate of a silane-based compound represented by _n SiX _4-n (m and n represent integers of 1 to 3, and X represents a halogen atom or an alkoxy group having 5 or less carbon atoms) is applied. A method for producing a highly water repellent material, which comprises heating and drying. 2. A method for producing a highly water repellent material, characterized in that the surface of the substrate according to claim 1 is an oxide layer of silicon or metal.