JP5022584B2 - Fluorocarbon silane-containing aqueous emulsion and water drop tumbling and water / oil repellency coating - Google Patents

Description

  The present invention relates to a fluorocarbon silane-containing aqueous emulsion capable of providing a coating layer having excellent water and oil repellency and water drop and other falling properties. More specifically, a surfactant, a silane compound, a compound having a linear or branched alkyl group and a reactive functional group together with fluorocarbon silane or a partial hydrolyzate of fluorocarbon silane, an aqueous emulsion containing a pH adjuster, and its The present invention relates to a coating formed by applying an emulsion to a substrate and drying, and having excellent water and oil repellency and water drop fallability.

  Various proposals have been made on silane-containing aqueous solutions that can provide water repellency to the surface of a substrate.

  Among the silane-containing aqueous solutions, a fluorocarbon silane hydrolyzate and a surfactant that emulsifies the hydrolyzate are included as those that can provide water repellency to the substrate without requiring special heat treatment. An emulsion has been developed (see Patent Document 1).

  Also proposed is an emulsion containing a fluorocarbon silane hydrolyzate, a surfactant for emulsifying the hydrolyzate, silicate, and a specific pH adjuster, the pH of which is adjusted to 4.5 or less. Therefore, heat-resistant and water-repellent properties can be provided to the substrate (see Patent Document 2).

Furthermore, as an emulsion that provides excellent heat and water repellency, an emulsion containing a fluorocarbon silane hydrolyzate, a surfactant that emulsifies the hydrolyzate, a specific silicate, and a pH adjuster has also been proposed. A coating layer having both water repellency and oil resistance and antifouling properties can be provided (see Patent Document 3).
US Pat. No. 5,550,184 JP 2001-329174 A JP 2001-335893 A

  Although the coating layer formed by applying and drying such an emulsion has excellent water and oil repellency, there is a problem that it is difficult to remove attached water droplets from the surface of the coating layer. Particularly in the window glass of automobiles and the like, there is a strong demand for further improvement of the water drop fallability in order to obtain a good field of view even when running in the rain.

  An object of the present invention is to provide a fluorocarbon silane-containing aqueous emulsion capable of forming a coating excellent in water repellency and water drop fallability.

The aqueous fluorocarbon silane-containing emulsion of the present invention comprises (i) a fluorocarbon silane or a partial hydrolyzate thereof, (ii) a surfactant, and (iii) a linear or branched alkyl group having 12 to 24 carbon atoms. An aqueous emulsion containing a compound having a reactive functional group, (iv) an alkoxysilane, and (v) a pH adjuster. The fluorocarbon silane is at least one hydrolyzable fluorocarbon silane represented by the formula (I).
_{R f - (CH 2) p} -Si {- (O-CH 2 CH 2) n -OR 1} 3 (1)

In the above formula (1), R _f is a perfluoroalkyl group having 3 to 18 carbon atoms, a plurality of R ¹ are the same or different alkyl groups having 1 to 3 carbon atoms, and p = 2-4 and n = 2-10.

The fluorocarbon silane is preferably contained in an amount of 0.1 to 20% by weight based on the total weight of the aqueous emulsion. The weight ratio of fluorocarbon silane to surfactant is preferably 1: 1 to 10: 1. The weight ratio of the fluorocarbon silane and the compound having a linear or branched alkyl group having 12 to 24 carbon atoms and a reactive functional group is 99: 1 to 70:30, and the alkoxysilane in the aqueous emulsion The content of is a mole fraction of alkoxysilane with respect to the fluorocarbon silane, and is preferably 0.1-10. The compound having a linear or branched alkyl group having 12 to 24 carbon atoms and a reactive functional group is preferably an alkyl ketene dimer, an alkyl succinic anhydride, an alkyl amine oxide or an alkyl mercaptan. The alkyl ketene dimer represented by 2) is more preferable .

In the formula (2), R ² and R ³ are hydrogen or a linear or branched alkyl group having 12 to 24 carbon atoms, both groups are not both hydrogen, and there are a plurality of alkyl groups. In some cases, they may be the same or different.

  The silane compound is preferably an alkoxysilane. Moreover, it is preferable that a pH adjuster is an acid or an alkali, and adjusts pH of an aqueous emulsion to 4.5 or less, or 7 or more using this.

  Another embodiment of the present invention is a coating having water drop and water / oil repellency, which is coated with the fluorocarbonsilane-containing aqueous emulsion and dried on at least one surface of the substrate. It comprises the coating layer formed by.

  ADVANTAGE OF THE INVENTION According to this invention, the fluorocarbon silane containing aqueous emulsion for implement | achieving the outstanding water drop fall property and the outstanding water repellency and oil repellency can be provided. In addition, the aqueous emulsion of the present invention is stable even when left for a long period of time. Therefore, a paint having excellent stability to consumers, water droplet adhesion prevention and water / oil repellency as a finished product. It is possible to provide. Furthermore, by applying and drying the aqueous emulsion of the present invention on various substrates, it is possible to provide a coating provided with a coating layer having excellent water droplet fallability and water / oil repellency as described above. . The water-based emulsion and coating of the present invention can easily remove water droplets adhering to the window even when driving in rainy weather, and the coating layer itself is thin and transparent, so that a good field of view can be obtained. it can.

  The aqueous emulsion of the present invention comprises (i) a fluorocarbon silane or a partial hydrolyzate thereof, (ii) a surfactant, (iii) a silane compound, (iv) a pH adjuster, and (v) 12 to 24 carbon atoms. A fluorocarbon silane-containing aqueous emulsion containing a compound having both a linear or branched alkyl group and a reactive functional group. The aqueous emulsion of the present invention can impart high water / oil repellency and high water drop tumbling property.

  In the present specification, the terms of tumbling and sliding are used interchangeably with respect to water tumbling. The term “dropping property” refers to the ease of movement of water droplets on the aqueous emulsion coating layer of the present invention provided on the coating (that is, the property that water droplets do not easily adhere to the coating layer).

Hereinafter, each component of the present invention will be described.
(I) Fluorocarbon silane or a hydrolyzate thereof The aqueous emulsion of the present invention contains a fluorocarbon silane or a partial hydrolyzate thereof.

  In the aqueous emulsion of the present invention, at least one fluorocarbon silane represented by the following formula (1) is used as the hydrolyzable fluorocarbon silane.

_{R f - (CH 2) p} -Si {- (O-CH 2 CH 2) n -OR 1} 3 (1)

In the formula (1), R _f is a perfluoroalkyl group having 3 to 18 carbon atoms or a mixture thereof, and a plurality of R ¹ are the same or different alkyl groups having 1 to 3 carbon atoms, And p = 2-4 and n = 2-10. Preferably, R _f is a mixed perfluoroalkyl group having an average of 8-12 carbon atoms, R ¹ is a methyl group, and p = 2 and n = 2-4. More preferably, n = 2 to 3.

  Specifically, a preferred fluorocarbon silane is perfluoroalkylethyltris (2- (2-methoxyethoxy) ethoxy) silane when n is 2, and perfluoroalkylethyltris (when n is 3). 2- (2- (2-methoxyethoxy) ethoxy) ethoxy) silane. Such a fluorocarbon silane can be produced by a known method.

In the aqueous emulsion of the present invention, two or more kinds of fluorocarbon silanes may be mixed and used. For example, a mixture of fluorocarbon silanes having different R _f can be used. In that case, it is preferable to select the type and amount of the fluorocarbon silane so that the average number of carbon atoms in R _f is 8 to 12.

In the aqueous emulsion, the fluorocarbon silane of the present invention may be at least a part of — (O—CH ₂ CH ₂ ) _n —OR ¹ group which is hydrolyzed to become —OH group. In other words, a partially hydrolyzed fluorocarbon silane or a fully hydrolyzed fluorocarbon silane having the structure of the following formula (1 ′) may be present in the aqueous emulsion of the present invention.

_{R f - (CH 2) p} Si (OH) q {- (O-CH 2 CH 2) n -OR 1} 3-q (1 ')

In formula (1 ′), 1 ≦ q ≦ 3, and n, p, R _f , and R ¹ are the same as in formula (1).

Thus, in this specification, fluorocarbon silane refers to (a) the fluorocarbon silane of the above formula (1) that has not undergone hydrolysis, and (b)-(O—CH ₂ CH ₂ ) of a part of the fluorocarbon silane. a partially hydrolyzed product in which the _n- OR ¹ group is partially hydrolyzed and partially becomes an —OH group, or (c) all — (O—CH ₂ CH ₂ ) _n — of the fluorocarbon silane. It is a general term for all hydrolysates in which the OR ¹ group has undergone hydrolysis to become —OH groups, or a mixture thereof. Moreover, the hydrolyzate of fluorocarbon silane refers to the above (b) or (c) and a mixture thereof.

  Therefore, in the present specification, the fluorocarbon silane-containing aqueous emulsion means an aqueous emulsion containing fluorocarbon silane and / or a partial hydrolyzate of fluorocarbon silane and / or a total hydrolyzate of fluorocarbon silane.

  The content of fluorocarbon silane in the aqueous emulsion is at least 0.1% by weight, preferably 0.1-20% by weight, more preferably, based on the total weight of the emulsion, in terms of unhydrolysed product. Is 1 to 20% by weight, more preferably 2 to 15% by weight. Sufficient water repellency can be achieved by setting the fluorocarbon silane content to 0.1% by weight or more, while good stability of the aqueous emulsion can be realized by setting it to 20% by weight or less. .

(Ii) Surfactant The surfactant used in the present invention is sufficient to suppress the self-condensation of the surfactant that can emulsify the fluorocarbon silane or the hydrolyzate thereof, that is, the fluorocarbon silane partial hydrolyzate. It is a surfactant having a high HLB value. Preferred surfactants are those with an HLB value greater than 12, more preferably greater than 16. In particular, when a large surfactant having an HLB value of 16 is used, the emulsion can be stabilized without using a very large amount of surfactant. The surfactant used in the present invention may be any of anionic, cationic, nonionic and amphoteric types. Moreover, as long as the surfactant has a sufficiently high HLB value to suppress self-condensation of the fluorocarbon silane partial hydrolyzate, two or more compatible surfactants may be mixed and used.

  The HLB value of non-ionic surfactants can be calculated by calculation formulas created by Mr. Griffin of Atlas (currently ICI America) of the United States. However, there is no method for obtaining the HLB value by calculation. However, Atlas Co., Ltd. has established and announced a method for experimentally determining the HLB value through standard oil emulsification experiments, focusing on the fact that the HLB value changes. Other than Atlas, a method for experimentally determining the HLB value has been established, but it is clear that the HLB value of anionic and cationic surfactants is greater than 16 regardless of which experimental method is employed. Has been.

Specific examples of the _{surfactant, R f '-CH 2 CH 2} -O- (CH 2 CH 2 O) 11 -H, C 9 H 19 -C 6 H 4 -O- (CH 2 CH 2 O) nonionic surfactants such as _{50 -H, R f '-CH 2} CH 2 SCH 2 CH (OH) CH 2 N (CH 3) 3 + Cl - cationic surfactants, such _as, C ₁₂ H 25 (OCH ^{_{2 CH 2) 4 OSO 3 -}} NH 4 +, C 12 H 27 -C 6 H 4 -SO 3 - can be exemplified anionic surfactants such as Na ^+. R _f ′ is a perfluoroalkyl group and usually has 3 to 18 carbon atoms.

  Preferred surfactants include nonionic surfactants having ethylene oxide repeating units (polyethylene glycol) in the molecular chain.

  The content of the surfactant is defined by the weight ratio between the fluorocarbon silane and the surfactant. This weight ratio is preferably 10: 1 to 10:10, more preferably 10: 2 to 10: 5, and even more preferably 10: 3. By using the surfactant in the weight ratio as described above, the aqueous emulsion can be stably maintained, and the hydrophilicity of the coating layer on the substrate after the aqueous emulsion is applied to the substrate and dried. Can be prevented to provide good water repellency.

(Iii) Compound having a linear or branched alkyl group having 12 to 24 carbon atoms and a reactive functional group The aqueous emulsion of the present invention has a water drop tumbling property when formed as a coating layer on a substrate. In order to improve, it contains a compound having a linear or branched alkyl group having 12 to 24 carbon atoms and a reactive functional group. Examples of the compound include alkyl ketene dimer, alkyl alkoxy silane, alkyl succinic anhydride, alkyl amine oxide, and alkyl mercaptan. In the present invention, alkyl ketene dimers are preferred. The alkyl ketene dimer is not particularly limited and may be a known one. Preferable examples of the alkyl ketene dimer include an alkyl ketene dimer having a linear or branched alkyl group having 12 to 24 carbon atoms at one end. The alkyl ketene dimer is represented by the following formula (2).

In the formula (2), R ² and R ³ are hydrogen or a linear or branched alkyl group having 12 to 24 carbon atoms, both groups are not both hydrogen, and there are a plurality of alkyl groups. In some cases, they may be the same or different.

  Suitable alkyl ketene dimers for use in the present invention include aqueous solution-dispersed alkyl ketene dimers. More specifically, for example, alkyl ketene dimer aqueous emulsions and the like can be mentioned.

  The content of the compound having a linear or branched alkyl group having 12 to 24 carbon atoms and a reactive functional group is not particularly limited as long as it can impart good water repellency and water drop fallability. For example, in the case of an alkyl ketene dimer, the content is given by the weight ratio of the fluorocarbon silane and the alkyl ketene dimer, and this weight ratio is preferably 99.9: 0.1 to 55:45, more preferably 99: It is 1-70: 30, More preferably, it is 95: 5-75: 25. By using an alkyl ketene dimer within the above-mentioned range, good water repellency and water drop fallability can be provided.

(Iv) pH adjuster Since the aqueous emulsion of the present invention adjusts the pH to 4.5 or less, or 7 or more, an acid or alkali pH adjuster can be appropriately used. The range of the pH value of the aqueous emulsion of the present invention is 4.5 or less, or 7 or more, more preferably pH 2.0 to pH 4.5 or pH 7.0 to pH 11.0, still more preferably pH 3.0 to 4.0 or pH 9.0-10.5.

  Such an acid or alkali is not particularly limited, and may be a known one. Examples of the acid include phosphoric acid, boric acid, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and formic acid. Moreover, as said alkali, ammonia, a pyridine, sodium hydroxide, ammonium hydroxide, sodium aluminate, potassium hydroxide etc. can be used, for example. In the present invention, it is particularly preferable to use hydrochloric acid, phosphoric acid, or ammonia as a pH adjuster.

  The addition amount of the pH adjusting agent to the aqueous emulsion is such an amount that the pH of the aqueous emulsion becomes a target pH within the above pH range.

(V) Alkoxysilane The aqueous emulsion of the present invention contains an alkoxysilane. The alkoxysilane in the present invention includes an organosilicon compound having two or more alkoxy groups in the molecule or a partial condensate thereof. For example, an organoalkoxysilane having the structure of the following formula (3) or the structure of the formula (4) can be used.

Si- (R ⁴ ) ₄ (3)

In the formula, R ⁴ is a group selected from the group consisting of OCH ₃ , OCH ₂ CH ₃ , and (OCH ₂ CH ₂ ) _m OCH ₃ (m = 1 to 10), and R ⁴ is the same. Or different.

R ⁵ _n Si (OR ⁶ ) _4-n (4)

In the formula, R ⁵ is an alkyl group having 1 to 10 carbon atoms, R ⁶ is an alkyl group having 1 to 3 carbon atoms, and when a plurality of R ⁵ and R ⁶ are present, Independently, the same or different groups are represented and n = 1-3.

The alkyl group represented by R ⁵ may be substituted with an appropriate substituent such as an amino group, an epoxy group, a vinyl group, a methacryloxy group, a thiol group, a urea group, a phenyl group, or a mercapto group.

  Specific examples of the organoalkoxysilane include, for example, dimethyldimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3 -Aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, or a mixture thereof or partial condensation thereof Thing etc. are mentioned.

  The alkoxysilane is preferably used in an amount of 10 or less in terms of a mole fraction relative to the fluorocarbon silane.

  The alkoxysilane is preferably stable from the viewpoint of easy handling of the aqueous emulsion, and in order to maintain a stable emulsion, the mole fraction of the alkoxysilane with respect to the fluorocarbon silane is 0.1 to 10 or less, preferably It is 0.1-4, More preferably, it is 0.2-2.

  Aqueous emulsions contain conventional additives such as pigments, biocides, UV absorbers, and antioxidants, stability of the emulsion, and water and oil repellency of coating layers formed from this aqueous emulsion, as well as water droplets. It can contain in the range which does not affect tumbling property.

  The method for preparing the aqueous emulsion is not particularly limited, but the fluorocarbon silane is added after dissolving the surfactant in water, then the alkyl ketene dimer and other additives as necessary, and the above acid or alkali. The method of adding alkoxysilane after adjusting pH by adding is preferable. Even if alkoxysilane is added after adjusting the pH of the emulsion, the pH does not change.

  In order to suppress the self-condensation of the fluorocarbon silane and keep it at least partially hydrolyzed, it is preferable to add the fluorocarbon silane after dissolving the surfactant, and further, stirring by a conventional stirring technique. However, it is preferable to slowly add the fluorocarbon silane.

  The present invention includes a coating comprising a coating layer obtained by applying the aqueous emulsion to at least a part of a substrate and drying it.

  An aqueous emulsion as described above can be applied to at least one surface of a substrate and subsequently dried to form a coating layer to produce a coating. In the present invention, a substrate made of a conventional material such as glass or metal, casting, ceramics such as earthenware, brick, concrete, stone or wood can be used as appropriate. In the present invention, the base material may be, for example, an automobile window glass.

  The application to the substrate can be performed by a known method such as a dipping method, a spray method, a spin coating method, a roll coating method, various brush coating methods, a screen printing method, and a gravure printing method.

  Heating may be used to promote drying. Usually, drying is performed at a temperature range of 100 to 350 ° C. for 5 minutes to 24 hours.

  If necessary, the coating obtained by applying the aqueous emulsion of the present invention and drying may be washed with water to remove the remaining surfactant.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples. The components used in the following examples and comparative examples are as follows.

(I) a fluorocarbon silane fluorocarbon _silane, R _f - a mixture of compounds having the structure represented by _{- {(O-CH 2 CH} 2) 2 -OCH 3} 3 (CH 2) 2 -Si. Specifically, R _f is F (CF ₂ ) _k , 1 to 2% by weight of a compound with k = 6; 62 to 64% by weight of a compound with k = 8; 30% by weight; 2 to 6% by weight of k = 12-18 compound. The weight percent of the Rf for the compounds of Korare is the weight percentage of each of _the R _f group to the total weight of the four compounds all R _f.

Surfactants, 'a nonionic surfactant represented by _{-CH 2 CH 2 -O- (CH 2} CH 2 O) 11 -H, R f' R f is 3 to 18 carbon atoms A perfluoroalkyl group having

(Ii) Alkyl ketene dimer As the alkyl ketene dimer, an alkyl ketene dimer aqueous emulsion, size pine K-903 (manufactured by Arakawa Chemical Industries) was used as it was.

(Iii) Alkoxysilane The alkoxysilane is tetrakis [2- (2-methoxyethoxy) ethoxy] silicate (Si (DEGM) ₄ ) or methyltriethoxysilane (CH ₃ —Si (OCH ₂ CH ₃ ) which is an organoalkoxysilane. ) ₃ (SiMe (OEt) ₃ )).

  Unless otherwise stated, the following test methods were used.

<Measurement of water and oil repellency angles>
2 μl of pure water or n-hexadecane was dropped on the surface of the coating layer of the obtained glass test piece, and the contact angle was measured with a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.).

<Measurement of water drop fallability>
The pure water which measured the volume with the micro syringe was dripped at the coating layer surface of the obtained glass test piece. Such dripping of pure water was performed on a plurality of coated surfaces for different volumes, and a plurality of water drops were spotted on a test piece. The specimen was slowly tilted and fixed at an angle of 45 degrees, and the state of the dropped pure water was observed. Of the multiple spots, the case where pure water slides down at least 3 cm within 30 seconds is considered to have slipped, and the minimum value of the volume (μl) of the plurality of water droplets sliding down at that time is measured. The amount of water fall.

(Examples 1-5 and Comparative Examples 1-2)
This example and a comparative example are for determining the optimum value of the alkylketene dimer addition amount.

  Surfactant in an amount of 30 parts by weight with respect to 100 parts by weight of fluorocarbon silane is dissolved in water, and then 10% by weight of fluorocarbon silane based on the total weight of the aqueous emulsion is slowly stirred with conventional stirring techniques. And added. With this procedure, the fluorocarbon silane can be kept in a hydrolyzed state with suppressed self-condensation. Then, alkyl ketene dimer (size pine K-903) was added in the amount shown in Table 1, and the mixture was stirred for 1 hour. Next, hydrochloric acid (HCl) as a pH adjusting agent was added while measuring the pH of the emulsion with a pH meter, and the addition was terminated when the pH reached 2.9. Further, an organoalkoxysilane was added so that the molar fraction of the organoalkoxysilane with respect to the fluorocarbon silane was 0.45, and the mixture was stirred for 2 to 4 hours to prepare an aqueous emulsion.

  Thereafter, the aqueous emulsion was applied to a glass plate (2.5 cm × 5.0 cm, thickness 3 mm) and dried to prepare a test piece.

  The aqueous emulsion was applied by dip coating. Dip coating was performed by lowering the test piece into the aqueous emulsion at a speed of 175 mm / min, holding the test piece in that state for 4 minutes, and pulling it up at a speed of 25 mm / min. Drying after coating was performed at 280 ° C. for 10 minutes.

  Table 1 shows the results of measuring the water repellency angle, oil repellency angle, and water drop fallability.

  Comparing Examples 1 to 5 and Comparative Examples 1 and 2, it can be seen that when the addition amount of the alkyl ketene dimer is 5 to 25 parts by weight with respect to the fluorocarbon silane, the water drop fallability is very good. Moreover, when the addition amount of the alkyl ketene dimer was 5 to 25 parts by weight with respect to the fluorocarbon silane, the coating film was visually transparent.

(Examples 6 to 10 and Comparative Examples 3 to 9)
In the examples and comparative examples, the types of the crosslinking agent and the pH adjusting agent were compared.

(Examples 6 to 10)
Surfactant in an amount of 30 parts by weight with respect to 100 parts by weight of fluorocarbon silane is dissolved in water, and then 10% by weight of fluorocarbon silane based on the total weight of the aqueous emulsion is slowly stirred with conventional stirring techniques. And added. With this procedure, the fluorocarbon silane can be kept in a hydrolyzed state with suppressed self-condensation. Next, an alkyl ketene dimer (size pine K-903) was added in an amount such that the weight ratio of the fluorocarbon silane and the alkyl ketene dimer was 75:25, and the mixture was stirred for 1 hour. Next, the pH adjuster shown in Table 2 was added while measuring the pH of the emulsion with a pH meter. In the case of the acid pH adjuster, the addition was terminated when the pH value reached 2.9, and in the case of the alkaline pH adjuster, the pH value reached 9.9. Furthermore, the alkoxysilane shown in Table 2 was added so that the mole fraction of the alkoxysilane with respect to the fluorocarbon silane was 0.45, and the mixture was stirred for 2 to 4 hours to prepare an aqueous emulsion.

(Comparative Examples 3 to 9)
An aqueous emulsion was prepared in the same manner as in Examples 6 to 10 except that the alkyl ketene dimer was not added.

  Then, the aqueous emulsion was apply | coated to the glass plate by the method similar to Examples 1-5, and the test piece was created.

  Table 2 shows the results of measuring the water repellency angle, oil repellency angle, and water drop fallability.

  When comparing Example 6 and Comparative Example 4, Example 7 and Comparative Example 5, Example 8 and Comparative Example 6, Example 9 and Comparative Example 7, Example 10 and Comparative Example 8, respectively, the type and pH of the alkoxysilane It can be seen that when the alkyl ketene dimer is added to the aqueous emulsion regardless of the type of the modifier and the combination thereof, the water drop fallability is improved. Moreover, when Example 6 and Comparative Example 3 are compared, it can be seen that when the alkyl ketene dimer is added together with the alkoxysilane, the water drop falling property is improved.

(Examples 11 to 15)
In this example, the effect of pH adjustment of the aqueous emulsion was tested.
Surfactant in an amount of 30 parts by weight with respect to 100 parts by weight of fluorocarbon silane is dissolved in water, and then 10% by weight of fluorocarbon silane based on the total weight of the aqueous emulsion is slowly stirred with conventional stirring techniques. And added. With this procedure, it is possible to maintain a hydrolyzed state in which self-condensation of the fluorocarbon silane is suppressed. Next, an alkyl ketene dimer (size pine K-903) was added in an amount such that the weight ratio of the fluorocarbon silane and the alkyl ketene dimer was 75:25, and the mixture was stirred for 1 hour. Next, the pH adjusting agent shown in Table 3 was added while measuring the pH of the emulsion with a pH meter. The addition of the pH regulator was terminated when the pH shown in Table 3 was reached. Furthermore, the alkoxysilane was added so that the mole fraction of the alkoxysilane with respect to the fluorocarbon silane was 0.45, and the mixture was stirred for 2 to 4 hours to prepare an aqueous emulsion.

  Then, the aqueous emulsion was apply | coated to the glass plate by the method similar to Examples 1-5, and the test piece was produced.

  Table 3 shows the results of measuring the water repellency angle, oil repellency angle, and water drop fallability.

Looking at Examples 11 to 15, it can be seen that when the pH of the aqueous solution is adjusted to 4.5 or less, or 7 or more, good water / oil repellency and water drop slidability can be obtained.

Claims (4)

(I) a fluorocarbon silane or a hydrolyzate thereof,
(Ii) a surfactant,
(Iii) a silane compound,
(Iv) an aqueous emulsion containing a pH adjuster, and (v) a compound having a linear or branched alkyl group having 12 to 24 carbon atoms and a reactive functional group,
The fluorocarbon silane has the following formula (1):
_{R f - (CH 2) p} -Si {- (O-CH 2 CH 2) n -OR 1} 3 (1)
Wherein R _f is a perfluoroalkyl group having 3 to 18 carbon atoms, a plurality of R ¹ are the same or different alkyl groups having 1 to 3 carbon atoms, and p = 2 to 2 4 and n = 2-10.)
At least one hydrolyzable fluorocarbon silane represented by
The compound having a linear or branched alkyl group having 12 to 24 carbon atoms and a reactive functional group is an alkyl ketene dimer, an alkyl succinic anhydride, an alkyl amine oxide or an alkyl mercaptan,
The silane compound is an alkoxysilane, and the alkoxysilane is represented by the following formula (3):
Si- (R ⁴ ) ₄ (3)
(In the formula, R ⁴ represents one or more groups selected from the group consisting of OCH ₃ , OCH ₂ CH ₃ , and (OCH ₂ CH ₂ ) _m OCH ₃ (m = 1 to 10).)
Or the following formula (4):
R ⁵ _n Si (OR ⁶ ) _4-n (4)
(In the formula, R ⁵ is an alkyl group having 1 to 10 carbon atoms, R ⁶ is an alkyl group having 1 to 3 carbon atoms, and when a plurality of R ⁵ and R ⁶ are present, Each independently represents the same or different group and n = 1-3.)
Is an organoalkoxysilane represented by
The fluorocarbon silane or a hydrolyzate thereof is contained in an amount of 0.1 to 20% by weight based on the total weight of the aqueous emulsion, and the weight ratio of the fluorocarbon silane to the surfactant is 1: 1 to 10: 1, the pH adjusting agent, the pH of the aqueous emulsion 4.5 or less, or, Ri acid or alkali der to adjust the 7 above, wherein the carbon atom and the fluorocarbon silane 12-24 of The weight ratio of the linear or branched alkyl group and the compound having a reactive functional group is 99: 1 to 70:30, and the content of alkoxysilane in the aqueous emulsion is alkoxysilane relative to the fluorocarbon silane. in a mole fraction, an aqueous emulsion, wherein 0.1 to 10 der Rukoto. A compound having a linear or branched alkyl group having 12 to 24 carbon atoms and a reactive functional group is represented by the following formula (2):

(Wherein R ² and R ³ are hydrogen or a linear or branched alkyl group having 12 to 24 carbon atoms, both groups are not both hydrogen, and when there are a plurality of alkyl groups, These may be the same or different.)
The aqueous emulsion according to claim 1, which is an alkyl ketene dimer represented by: One or more of the R ⁵ is an amino group, an epoxy group, claim 1, wherein the vinyl group, methacryloxy group, a thiol group, a urea group, an alkoxy silane which is substituted with a phenyl group or a mercapto group An aqueous emulsion as described in 1. A base material, and a water / oil / oil repellency and water drop tumbling coating layer formed by applying and drying the aqueous emulsion according to any one of claims 1 to 3 on at least one surface of the base material; A covering characterized by comprising.