JPH0959605A - Water repellent treatment - Google Patents

Abstract

(57) [Abstract] [Problem] Water repellency that is excellent in water repellency-imparting effect and water drop falling effect, and can impart excellent water repellency and antifouling property to the surface of a treated object, and is soluble in an organic solvent. Obtain the treating agent. A hydrolyzate is obtained by hydrolyzing a perfluoroalkyl group-containing organosilicon compound represented by the following general formula (I) in a tertiary alcohol having 4 to 11 carbon atoms. Embedded image (However, in the formula, R ¹ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, R ² is an alkoxy group or acyloxy group having 1 to 4 carbon atoms, and Q is a divalent organic group having 2 to 10 carbon atoms. Is a group, a is 0 or 1, and p is an integer of 1 to 12.)

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water repellent treatment agent soluble in an organic solvent capable of imparting excellent water repellency and antifouling property to an inorganic surface such as glass, ceramics and metal. In particular, it relates to a water repellent treatment agent capable of imparting self-cleaning property to an inorganic surface by rainwater.

[0002]

2. Description of the Related Art Conventionally, various studies have been conducted to improve the properties of the surface of inorganic materials such as glass, ceramics and metals by treating them with various surface treatment agents to improve their performance and expand the range of applications. It is being appreciated. As one of them, there has been proposed a method in which an originally hydrophilic surface is treated with a silicone composition to modify it into a water-repellent surface, and in particular, JP-A-58-14.
No. 7484, No. 60-212470 and JP-A-4-9.
Japanese Patent No. 6935 describes that a polysiloxane or polysilazane containing a perfluoroalkyl group is excellent in water repellency. However, the water repellent treatment agent,
Although it is excellent in water repellency, it is inferior in the drop property of water drops, so when it is applied as an antifouling agent for window glass of buildings such as houses and buildings, it does not drop and drops like dots on the glass surface. There is a case where dust stays in the air and dust, oil, and the like in the air adhere to it, which may contaminate it.

Further, Japanese Patent Application Laid-Open No. 3-290437 proposes a fluorine-containing silazane compound. Although this compound has improved the above-mentioned drawbacks, it has poor solubility in general organic solvents and is subject to CFC regulation. However, there is a problem that it is only soluble in fluorocarbons such as 1,1,3-trichlorotrifluoroethane and expensive fluorohydrocarbons, which limits the application range. .

Further, Japanese Patent Laid-Open No. 5-311156 proposes a water repellent treatment agent containing a fluoroalkylsilane, an acid catalyst and water in an alcohol solution such as methanol, ethanol and isopropanol. However, in the above-mentioned water repellent treatment agent, esterification by alcohol such as methanol, ethanol, isopropyl alcohol and the like makes it difficult to hydrolyze, so that it becomes difficult to generate silanol groups and the generated silanol groups are unstable. Therefore, the condensation reaction proceeds and the silanol groups decrease, so that the amount of silanol groups that can react with the inorganic surface is reduced, a strong bond cannot be formed, and the durability becomes poor.

[0005]

The present invention has been made in view of the above circumstances, and is excellent in a water repellency-imparting effect and a water drop falling property improving effect, and imparts excellent water repellency and antifouling property to a surface of an object to be treated. It is an object of the present invention to provide a water-repellent treatment agent that can be obtained and is soluble in an organic solvent.

[0006]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventor has found that a perfluoroalkyl group-containing organosilicon compound represented by the following general formula (I) has 4 to 11 carbon atoms. It was found that a hydrolyzate hydrolyzed in a tertiary alcohol, particularly t-butyl alcohol, has excellent properties as a water repellent treatment agent.

Embedded image (However, in the formula, R ¹ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, R ² is an alkoxy group or acyloxy group having 1 to 4 carbon atoms, and Q is a divalent organic group having 2 to 10 carbon atoms. Is a group, a is 0 or 1, and p is an integer of 1 to 12.)

That is, in the above hydrolyzate, the perfluoroalkyl group-containing organosilicon compound of the formula (I) contributes to the water repellency-providing effect and also has a silanol group which is highly reactive with the inorganic surface by hydrolysis. Therefore, excellent water repellency and antifouling property can be given to the surface of the object to be treated. Moreover, by using a tertiary alcohol having 4 to 11 carbon atoms as a solvent, the bulkiness of the tertiary alcohol causes te
Since the rt-alkoxylation reaction is suppressed, the hydrolysis proceeds, the silanol group is sufficiently generated, and the silanol group and the tertiary alcohol are hydrogen-bonded to each other, so that the silanol group is stabilized, and thus the silanol that can react with the inorganic surface is obtained. It has a large amount of base, can be firmly bonded, and can be imparted with highly durable water repellency and antifouling property.

Therefore, the present invention comprises a hydrolyzate obtained by hydrolyzing a perfluoroalkyl group-containing organosilicon compound represented by the above general formula (I) in a tertiary alcohol having 4 to 11 carbon atoms. A water repellent treatment agent is provided.

The present invention will be described in more detail below. The raw material of the water repellent treatment agent of the present invention is a perfluoroalkyl group-containing organosilicon compound represented by the following general formula (I).

Embedded image (However, in the formula, R ¹ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, R ² is an alkoxy group or acyloxy group having 1 to 4 carbon atoms, and Q is a divalent organic group having 2 to 10 carbon atoms. Is a group, a is 0 or 1, and p is an integer of 1 to 12.)

In the above formula (I), examples of R ¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and s-butyl group, and R ² includes For example, methoxy group, ethoxy group,
Examples thereof include an n-propoxy group, an isopropoxy group, an isopropenoxy group, an n-butoxy group, an acetoxy group and the like, and a methoxy group and an ethoxy group are preferable. Q is a group that bonds a perfluoroalkyl group and a silicon atom, and examples thereof include a divalent hydrocarbon group or a divalent hydrocarbon group containing an oxygen atom, a nitrogen atom or a sulfur atom in the molecule, and specifically- CH ₂ C
_{H 2 -, - CH 2 OCH} 2 CH 2 CH 2 -, - CONH
_{CH 2 CH 2 CH 2 -,} - CONHCH 2 CH 2 NHC
_{H 2 CH 2 CH 2 -,} - SO 2 NHCH 2 CH 2 CH 2
_{-, - CH 2 CH 2 OCONHCH} 2 CH 2 CH 2 - group and the like. Further, p represents the carbon number of the perfluoroalkyl group and is 1 to 12, preferably 1 to 8. When p exceeds 12, the solubility in organic solvents deteriorates. a is 0 or 1, and 0 is preferable.

Specific examples of the perfluoroalkyl group-containing organosilicon compound of the above formula (I) include the following compounds. One of these compounds may be used alone or 2
More than one kind can be mixed and used.

Embedded image

The solvent used in the present invention is a tertiary alcohol having 4 to 11 carbon atoms. Particularly preferably t
-Butyl alcohol. As described above, the durability of the water-repellent treatment agent becomes insufficient for primary alcohols and secondary alcohols, and when the number of carbon atoms is 12 or more, the compatibility with water becomes poor and the hydrolysis becomes unstable. The amount of the tertiary alcohol having 4 to 11 carbon atoms is not particularly limited, but the concentration of the compound of the formula (I) is preferably 1 to 30% by weight, particularly 3 to 15% by weight.

Further, although water is used for the hydrolysis, the amount of water added is 0.5 equivalent or more, particularly 0.5 equivalent to the total amount of alkoxy groups and acyloxy groups contained in the compound of formula (I). ~ 3 equivalents are preferred. If the amount is less than 0.5 equivalent, the hydrolysis rate may be insufficient and the reactivity with the inorganic surface may be weakened. If the amount exceeds 3 equivalents, the storage stability may be deteriorated.

In the present invention, a small amount of acid may be added so that the pH of the system is less than 7, preferably pH 5 or less for the purpose of promoting the reaction during hydrolysis. Examples of the acid include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, paratoluenesulfonic acid, trifluoroacetic acid, phosphoric acid and the like.

The above-mentioned hydrolysis reaction is not particularly limited, but is preferably carried out at 20 to 100 ° C. for 2 to 24 hours.

For the water repellent agent of the present invention, a solution containing the above-mentioned hydrolyzate may be used as it is, but if necessary, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve and acetic acid cellosolve, acetone, methyl ethyl ketone. Such as ketones, ethers such as dioxane and tetrahydrofuran, hydrocarbons such as pentane and hexane, isoparaffin hydrocarbon oil, or aromatic hydrocarbons such as benzene, toluene and xylene, esters such as ethyl acetate and isobutyl acetate. You may use it, after diluting with an organic solvent, such as a class, to a concentration of about 0.1 to 5%.

As a method of using it on the object to be treated, a durable water-repellent and antifouling surface can be obtained by dipping, spraying, brush coating, spinner or the like on the surface of the object to be treated and drying. . It should be noted that drying at room temperature is sufficient,
It is more preferable to heat at ~ 200 ° C for 5 to 60 minutes from the viewpoint of durability.

[0018]

The water repellent agent of the present invention is excellent in the effect of imparting water repellency and the effect of improving the drop property of water drops, and can impart excellent water repellency and antifouling property to the surface of an object to be treated, and further, an organic solvent. It is soluble in water and can be used for surface treatment of materials with various inorganic surfaces. Specifically, it is an optical component such as window glass for buildings, railways, vehicles, aircrafts, mirrors, glass lenses, etc. It can be widely used for surface treatment of various glass appliances, pottery, tiles, plastic materials treated with inorganic antireflection coat, silicone hard coat and the like.

[0019]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Example 1 20.0 g of a perfluoro group-containing organosilicon compound represented by the formula C ₈ F ₁₇ CH ₂ CH ₂ Si (OCH ₃ ) ₃ was added to a 2 liter glass reactor equipped with a thermometer, a stirrer and a condenser.
320.0 g of rt-butanol and 4.6 g of 0.05N hydrochloric acid water were charged, and a hydrolysis reaction was carried out at 25 ° C. for 24 hours. Further, 640.0 g of hexane was added and diluted to obtain a water repellent treatment agent solution. Examples 2-8, Comparative Examples 1-7 Perfluoro group-containing organosilicon compound of Example 1, hydrochloric acid water,
A water repellent agent solution was obtained in the same manner as in Example 1 except that the types and addition amounts of the solvent and the diluting solvent and the hydrolysis conditions were changed as shown in Table 1.

Next, 0.1 ml of the water repellent treatment solution obtained in each of the above Examples and Comparative Examples was applied onto a glass plate of 30 mm × 150 mm which had been degreased and washed with acetone in advance and dried in air for 10 minutes. Excessive coating liquid was wiped off with ethyl alcohol to prepare a water-repellent treated glass plate. Further, in order to examine the durability, the water-repellent treated glass plate was immersed in hot water at 100 ° C. for 6 hours.

With respect to these surfaces, the contact angle of water and the drop angle of water droplets were measured by the following methods, and the initial water repellency and durable water repellency were examined. The results are shown in Table 1. Contact Angle of Water 5 μl of water was dropped on a glass plate kept horizontal, and the contact angle was measured by a contact angle measuring device CA-A (manufactured by Kyowa Kagaku Co., Ltd.). Drop angle of water drop A static friction coefficient measuring device HEIDON-10 type (manufactured by Shinto Kagaku Co., Ltd.) was used to set a glass plate horizontally, and 100 μl of water was dripped, and then gradually tilted to start dropping water. The angle was measured.

[0022]

[Table 1]

[Table 2]

Claims (2)

[Claims] 1. A hydrolyzate obtained by hydrolyzing a perfluoroalkyl group-containing organosilicon compound represented by the following general formula (I) in a tertiary alcohol having 4 to 11 carbon atoms. A characteristic water repellent agent. Embedded image (However, in the formula, R ¹ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, R ² is an alkoxy group or acyloxy group having 1 to 4 carbon atoms, and Q is a divalent organic group having 2 to 10 carbon atoms. Is a group, a is 0 or 1, and p is an integer of 1 to 12.) 2. The water repellent agent according to claim 1, wherein the tertiary alcohol is t-butyl alcohol.