JP2014111709A - Water-repellent coating agent excellent in surface slipperiness and method for producing coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating agent capable of obtaining a coating film excellent in water repellency, wear resistance, deep glossiness, slipperiness on a coating film surface and durability and to provide a coating film excellent in slipperiness as a coating film, removability of dirt or dust or the like, and further to provide a method for producing a coating film excellent in coating characteristics without occurrence of coating spots even on a large-sized substrate.SOLUTION: There is provided a water-repellent coating agent containing the following components (1) to (4), wherein the water-repellent coating agent is applied to a substrate and followed by curing by naturally drying at room temperature to obtain a coating film excellent in durability: (1) a dimethylsilicone polymer having silanol groups at both the terminal positions and having a number average molecular weight of 50,000 to 20,0000; (2) a trifunctional silane compound and/or a partially hydrolyzed product thereof; (3) a metal compound-based curing agent; and (4) a solvent.

Description

The present invention relates to a water-repellent coating agent suitable for production of a water-repellent coating film having excellent durability and surface slipperiness, a coating film, and a method for producing the coating film.

Conventionally, by applying water-repellent coating agents made of fluorine-based materials and silicone-based materials that can reduce the surface energy, and these water-repellent coating agents for the purpose of preventing contamination by rainwater etc. on the surfaces of various substrates. Obtained water-repellent coating films have been studied. In particular, in order to improve the durability of the coating film, a method has been used in which a water-repellent coating agent is applied to the surface of various substrates, and then a crosslinking reaction is performed by heat treatment or irradiation with actinic rays such as ultraviolet rays. It was.

As the fluorine-based material, a material containing a fluorinated alkyl group (Rf group) is known. Such a material can impart water repellency by allowing Rf groups to be present only on the surface, but has a problem that it is inferior in durability such as an effect of improving the slipperiness of the coating film surface and wear resistance.

In addition, for the purpose of improving durability, a method for producing a material having a surface excellent in water repellency and abrasion resistance by applying a coating treatment comprising an acrylic UV curable resin and a fluorine surface modifier has been proposed. . However, it has a problem that it requires a special processing apparatus and lacks general versatility, such as being difficult to apply to a large-sized substrate or an irregular substrate material, in addition to poor slipperiness of the coating film surface.

On the other hand, a curable material made of a dimethyl silicone compound having silanol groups or acrylic groups at both ends is known as a silicone material. Since these materials have a structure in which not only the surface but also the inside is three-dimensionally cross-linked, they have a feature of having excellent wear resistance. However, the conventional silicone-based material has a problem that special equipment such as a heating device or an ultraviolet irradiation device is required. Furthermore, there is a problem that it is difficult to combine practically important design properties such as water repellency and deep gloss and prevention of contamination by rainwater. Furthermore, since the molecular weight of the silicone-based material is small, there is also a problem that the slipperiness of the coating film surface is inferior.

Also, it has been proposed to obtain a water-repellent surface by forming protrusions made of a water-repellent material on the surface, but there is a problem that the half surface having high water repellency is also inferior in wear resistance and lacks durability. Furthermore, since it also has a drawback of reducing glossiness, it is not preferable for applications in which design properties are particularly important.

Furthermore, a moisture-curing coating agent that cures with the humidity of the outside air without using a special device has also been proposed, but the water repellency and surface slipperiness are insufficient, or the film thickness of the coating film is insufficient. Therefore, it has a problem that it is difficult to obtain a surface that achieves both water repellency and glossiness.

Japanese Patent Laid-Open No. 62-148902 Japanese Patent Laid-Open No. 11-269287 JP 2006-346900 A JP-A-10-36771 JP 2008-75021 A

  In view of the above-mentioned conventional drawbacks, the present invention has a water repellent coating excellent in durability, having excellent practicality such as surface slipperiness, abrasion resistance and deep gloss in addition to excellent water repellency. It aims at providing the water-repellent coating agent suitable for preparation of a film | membrane.

Furthermore, by applying the water-repellent coating agent of the present invention, it is possible to provide a water-repellent coating film excellent in surface slipperiness under a mild condition such as in a natural environment without using a special processing apparatus, and good Another object of the present invention is to provide a method for producing a coating film having a good appearance.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a water-repellent coating agent characterized by containing the following components (1) to (4).
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof (3) Metal compound curing agent ( 4) Solvent

Further, the present inventor is a film obtained by curing a coating agent containing the following components (1) and (2) as a coating film for solving the above-mentioned problems, and the surface friction coefficient of the film is 0.165 or less. A coating film characterized by the above has been found.
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof

In addition, as a method for producing a coating film that solves the above-mentioned problems, the present inventors have produced a water-repellent coating film characterized by applying a water-repellent coating agent and spreading using a cloth composed of ultrafine long fibers. I found a way. In particular, it has been found that application to a water-repellent coating agent comprising the following components (1) to (4) is useful.
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof (3) Metal compound curing agent ( 4) Solvent

In the present invention, a dimethyl silicone polymer having silanol groups at both ends and having a number average molecular weight (Mn) of 50,000 to 200,000 has silanol groups represented by Si—OH at both ends, and a commercially available material is used. Is possible.

In order to obtain high water repellency, a coating film having a so-called high water static contact angle, and a so-called high surface slipperiness having a small coating surface friction coefficient, a dimethyl silicone polymer having a number average molecular weight (Mn) of 50,000 or more is used. It is necessary. A dimethylsilicone polymer material having a number average molecular weight (Mn) of less than 50,000 and a small molecular weight cannot provide high water repellency or good coating surface slipperiness. Number average molecular weight (Mn) is 55,000 or more to obtain high water repellency or coating surface slipperiness with a thinner film thickness, and number average molecular weight to obtain higher water repellency and coating surface slipperiness. It is preferable to use a dimethyl silicone polymer having silanol groups at both ends with (Mn) of 60,000 or more.

On the other hand, a dimethyl silicone polymer material having a high number average molecular weight (Mn) is useful for developing deep glossiness in addition to high water repellency and coating surface slipperiness. ) Increases, the thixotropy becomes stronger. In particular, when it exceeds 200,000, the gel effect at the time of curing increases, and it tends to be difficult to form a uniform coating film.

However, with a dimethyl silicone polymer having a number average molecular weight (Mn) of up to 200,000, a uniform coating film can be obtained by improving the coating method. However, if it exceeds 200,000, it is not only difficult to cope with the coating method, but it is difficult to produce the material itself, it is difficult to obtain, and the cost is high.

In order to further improve the compatibility between the material having a high number average molecular weight (Mn) and the component (2) of the present invention, it is also preferably used in combination with a dimethyl silicone polymer having a relatively small number average molecular weight (Mn).

The number average molecular weight (Mn) referred to in the present invention can be easily measured by using a GPC system (Gel Permeation Chromatography System) used for measuring the molecular weight of ordinary synthetic polymers. For example, a method using a high-speed GPC apparatus (HLC-8220GPC) manufactured by Tosoh Corporation and using chloroform as a developing solvent can be mentioned.

The number average molecular weight (Mn) effective for improving the compatibility described above for the purpose of improving the ease of use of the water-repellent coating agent of the present invention, controlling the curing rate, improving stickiness, and improving the antifouling property to oil and fat components, etc. ) Is less than 50,000, it is possible to use a dimethyl silicone polymer having silanol groups at both ends.

Furthermore, for the purpose of controlling the refractive index of the coating film, a silicone polymer having silanol groups at both ends containing a phenyl group or a trifluoropropyl group can be used in combination. In particular, in order to obtain a coating film having a lower refractive index that makes it possible to suppress surface reflection, it is preferable to use a trifluoropropyl group-containing silicone polymer in combination.

The water-repellent coating agent of the present invention is hardly said to have excellent wettability to the substrate. However, since the water-repellent coating agent of the present invention is applied to an extremely thin film thickness, uniform application and durability can be ensured by the affinity between the polymer and the substrate.

In order to improve the wettability with the substrate and improve the coating properties, it is necessary to use a dimethyl silicone polymer having silanol groups at both ends having a number average molecular weight (Mn) of less than 50,000 to lower the coating performance. It is preferable because it is possible without any problems.

Addition amount of dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of less than 50,000, phenyl group-containing silicone polymer, trifluoropropyl group-containing silicone polymer, etc. decreases water repellency. It tends to reduce the slipperiness of the coating film surface, or to reduce the glossiness with a depth, so it should be determined in relation to the target properties.

Materials that can be obtained as dimethyl silicone polymers having silanol groups at both ends having a number average molecular weight (Mn) of 50,000 to 200,000 as component (1) of the present invention include DMS-S42, DMS-S45, DMS-S51 (GELEST Inc.).

These dimethyl silicone polymers having silanol groups at both ends can be used alone or in combination of two or more.

Examples of materials that can be used in combination with the above component (1) of the present invention as dimethyl silicone polymers having silanol groups at both ends having a number average molecular weight (Mn) of less than 50,000 include PRX413, BY16-873 (Toray Dow Corning), X-21-5841, KF-9701 (Shin-Etsu Silicone), DMS-S12, DMS-S14, DMS-S15, DMS-S21, DMS-S27, DMS-S31, DMS-S32, DMS-S33 And DMS-S35 (manufactured by GELEST Inc.).

PDS-0338 and PDS-1615 (manufactured by GELEST Inc.) as phenyl group-containing silicone polymers having silanol groups at both ends, and FMS-9921 and FMS-9922 (GELEST Inc. as trifluoropropyl group-containing silicone polymers). Manufactured).

Next, component (2) will be described below. The component (1) contained in the water-repellent coating agent of the present invention is liquid or fluid by itself, but is a highly viscous liquid, has poor water repellency in an uncured state, and has a large stickiness. Therefore, a practical coating film cannot be obtained.

Therefore, in order to obtain a coating film containing the component (1) having excellent water repellency and slipperiness, it is necessary to perform three-dimensional crosslinking. The component used for that purpose is component (2).

That is, by using the component (2), the coating film has a three-dimensional cross-linking structure, has water repellency, durability such as abrasion resistance, weather resistance, etc., and imparts slipperiness of the coating surface. Is possible.

Here, the content of the component (2) of the present invention is sufficient as long as the component (1) is three-dimensionally cross-linked so as to contain an amount capable of imparting stickiness and durability. In order to enable curing at room temperature, which is a characteristic, it is desirable to use 5 to 1,000 parts by weight of component (2) with respect to 100 parts by weight of component (1). Further, in order to satisfy both performance of water repellency and slipperiness, it is preferable to use 10 to 900 parts by weight of component (2) with respect to 100 parts by weight of component (1).

In addition, the weight part in the component (2) indicates the number of parts defined as the weight when the amount of the residual compound after the compound used is cured by moisture or the like becomes constant. Incidentally, since the component (1) has substantially no volatility, the used weight itself becomes part by weight. Therefore, the weight part of the component (2) can be obtained as a weight part obtained by subtracting the component (1) from the total weight part after curing.

Component (2) is a trifunctional silane compound and / or a partially hydrolyzed condensate thereof, which is a component (1) dimethyl silicone having silanol groups at both ends and having a number average molecular weight (Mn) of 50,000 to 200,000 It is not particularly limited as long as it is a material that can cure the polymer without requiring a special device, but from the viewpoint of curing speed, stability of the cured film, and further imparting durability of water repellency and slipperiness of the cured film. The following materials are preferably used.

Here, as a trifunctional silane compound, the silane compound represented by the following general formula (A) is mentioned.
R ¹ Si (OR ² ) ₃ (A)
(Here, R ¹ is an alkyl group having 1 to 3 carbon atoms or an alkenyl group, and OR ² is a hydrolyzable group).

  Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Among them, examples of the alkyl group having an excellent balance between water repellency and wear resistance include a methyl group and an ethyl group. Furthermore, examples of the alkyl group that can further enhance the durability include a methyl group.

  Examples of the alkenyl group include a vinyl group and an allyl group. Among them, a vinyl group is preferably used because of its high stability to heat and moisture and easy availability.

Next, OR ² which is a hydrolyzable group will be described. OR ² is not particularly limited as long as it is a functional group capable of being hydrolyzed, but from the viewpoint of easy hydrolysis, that is, hydrolysis reaction can be easily performed by moisture in the air. An acyloxy group and a lower alkoxy group are preferably used.

  Among these, considering a curing treatment by standing in a room temperature environment, an acetoxy group, a methoxy group, and an ethoxy group are preferable hydrolyzable groups because of excellent hydrolyzability and volatility after hydrolysis. Furthermore, considering that it is desired that the coating agent of the present invention can be applied even in an environment that does not have special ventilation facilities, a methoxy group and an ethoxy group are preferable from the viewpoint of odor and irritation after volatilization. Of these, a methoxy group is most preferred because it has moderate hydrolyzability, excellent volatility and little odor.

As the partially hydrolyzed condensate of the trifunctional silane compound, a compound obtained by hydrolyzing the silane compound represented by the general formula (A) with water that does not gel and then condensing the hydrolyzate by aging In addition, there is a compound in which condensation is further advanced by concentrating.

  Here, the silane compound represented by the general formula (A) is a trifunctional silane compound, and further, the hydrolyzate is not gelled to enable solution coating, and the partially hydrolyzed condensate In view of the effect to be added, the amount of water used for hydrolysis is 1.20 mol to 0.04 mol with respect to 1 mol of the trifunctional silane compound, 1.10 mol to 0.04 mol to further suppress gelation, It is desirable that it is 1.05 mol-0.04 mol. That is, when the amount is less than 0.04 mol, the remaining amount of the unreacted trifunctional silane compound is increased, and the effect of forming a partially hydrolyzed condensate is reduced.

Further, in the case of a trifunctional silane compound in which a hydrolyzable group has a methoxy group or an ethoxy group and the R ¹ functional group has a lower alkyl group and easily undergoes a crosslinking reaction, 1.10 mol to 0.40 mol More preferably, 1.05 mol to 0.50 mol is most preferable.

In the hydrolysis, in order to make the hydrolysis reaction proceed smoothly and more reliably, it is also useful means to add an acid or a base to the water to be used, or to warm it. In particular, when dealcoholization or deacetic acid is carried out after hydrolysis, dilute hydrochloric acid is preferred as the acid used for hydrolysis in order not to leave any acid or base in the partially hydrolyzed condensate after concentration. The concentration of dilute hydrochloric acid varies depending on the type of hydrolysis functional group and the type of R ¹ functional group, but usually 0.005N to 1.500N hydrochloric acid is used.

  Since the trifunctional silane compound represented by the general formula (A) is usually poor in compatibility with water, it becomes a heterogeneous reaction until the hydrolysis reaction partially proceeds. Addition of alcohol or the like to the trifunctional silane compound for the purpose of making the reaction uniform is also preferably applied. The alcohol added at that time is preferably the same or lower alcohol than the alcohol formed after hydrolysis.

The hydrolysis reaction is usually carried out by adding water to the trifunctional silane compound. However, there is no problem even if the water to be added is added dropwise while stirring or added all at once. In addition, since the hydrolysis reaction is a reaction accompanied by heat generation, it is also a preferred embodiment that the external temperature is cooled in order to suppress abnormal volatilization of alcohol generated by hydrolysis.

In addition, dehydration condensation after hydrolysis can proceed sufficiently by aging at room temperature, but in order to proceed with dehydration condensation more reliably, dehydration condensation is more complete by concentrating the hydrolyzate by dealcoholization etc. The reaction can proceed.

The obtained partial hydrolysis-condensation product can be confirmed from an analysis result by FT-IR, GC / MS, etc., to be a compound having an alkoxy group having substantially no silanol group or an acyloxy group as a substituent. .

Specific examples of the trifunctional silane compound represented by the general formula (A) in the present invention include methyltriacetoxysilane, ethyltriacetoxysilane, propyltriacetoxysilane, isopropyltriacetoxysilane, and vinyltriacetoxysilane. , Methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, isopropyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, isopropyltriethoxysilane, vinyltriethoxysilane , Methyltripropionoxysilane, ethyltripropionoxysilane, propyltripropionoxysilane, isopropyltripropionoxysilane, vinyltripropio Noxysilane, methyltripropoxysilane, ethyltripropoxysilane, propyltripropoxysilane, isopropyltripropoxysilane, vinyltripropoxysilane, methyltributoxysilane, ethyltributoxysilane, propyltributoxysilane, isopropyltributoxysilane, vinyltributoxy Silane etc. are mentioned.

  These trifunctional silane compounds can be added and mixed in the composition as they are. However, in general, many trifunctional silane compounds have volatility and partly volatilize at the coating stage, and the amount of volatilization greatly depends on the environment such as temperature and humidity. Since it becomes a dispersion | variation factor, it is also preferable to hydrolyze beforehand and to use as a partial hydrolysis-condensation product. Moreover, since the partial hydrolysis-condensation product increases the number of hydrolysis functional groups in one molecule, it has the effect of increasing the degree of crosslinking, and as a result, it is also effective in improving the durability of the coating film.

Trifunctional silane compounds can be used alone, but for the purpose of improving the balance between abrasion resistance, curing speed and water repellency, two or more types of trifunctional silane compounds including partially hydrolyzed condensates are available. Needless to say, the compounds may be used in combination.

  Trifunctional silane compounds that satisfy the performances of wear resistance, water repellency, and slipperiness, and further improve the durability of these performances. In addition, they are easy to handle because they are liquid at room temperature. Of these, trifunctional silane compounds having a lower alkyl group and a lower alkoxy group or a lower acyloxy group are preferred. Of these, an ethyltriacetoxysilane compound is particularly preferably used as the methyltrimethoxysilane compound, ethyltrimethoxysilane compound, methyltriethoxysilane compound, ethyltriethoxysilane compound, or acyloxysilane compound.

A mixed system of an ethyltriacetoxysilane compound and a methyltriacetoxysilane compound can be handled as a liquid at room temperature, and can further increase the degree of cross-linking, and can be mentioned as one of preferred embodiments. .

Furthermore, partial hydrolysis condensates of trifunctional silane compounds include methyltrimethoxysilane compounds, methyltriethoxysilane compounds, ethyltrimethoxysilane compounds, and ethyltriethoxysilane compounds. It is most preferable because it is excellent in compatibility with excellent solvent compatibility and further in reactivity after coating.

Examples of the structure of the partial hydrolysis-condensation product of the trifunctional silane compound include a chain structure and a cyclic structure. In any structure, a functional group such as an alkoxy group or an acetoxy group that can undergo a crosslinking reaction after coating. have. In particular, the alkoxy group is preferably a lower alkoxy group such as a methoxy group or an ethoxy group from the viewpoint of coating stability, reactivity after application, volatility, and the like.

A trifunctional silane compound having two or more of an acetoxy group and an alkoxy group in one molecule of a trifunctional silane compound is also preferably used from the viewpoint of curing rate control. A trifunctional silane compound having two types of functional groups of an acetoxy group and an alkoxy group in one molecule can be obtained by a substitution reaction by adding appropriate amounts of various alcohols to the triacetoxysilane compound, and simply stirring and mixing. it can. Moreover, it can also obtain more easily by performing a heating etc. as needed.

Trifunctional silane compounds and partial hydrolysis condensates of trifunctional silane compounds, as well as component analysis and structural analysis of trifunctional silane compounds obtained by substitution reaction of triacetoxysilane compounds with various alcohols, GC / MS, It can be done easily with FT-IR.

Next, the metal compound type curing agent as component (3) will be described. By using a metal compound-based curing agent, a film excellent in water repellency, slipperiness, durability, and abrasion resistance can be obtained without coloring the coating film.

Examples of such metal compound curing agents include tin compounds, aluminum compounds, zirconium compounds, and various titanium compounds. Of these, tin compounds and aluminum compounds are particularly preferred because of the stability of the paint, the balance between the curing speed and the durability of the cured film, and the ability to obtain a colorless coating film. In particular, a tin compound having an organic group is preferably used because it does not cause a substantial decrease in water repellency due to addition, and among them, a bifunctional organotin compound is more preferably used from the viewpoint of safety.

As the bifunctional organotin compound, a material represented by the following general formula (B) is exemplified as a most preferable compound example from the viewpoint of curability and durability in addition to safety.
R ³ R ⁴ Sn (OR ⁵ ) ₂ (B)
(Here, R ³ and R ⁴ are hydrocarbon groups having 2 to 12 carbon atoms, and OR ⁵ is a hydrolyzable group).

Examples of the hydrocarbon group having 2 to 12 carbon atoms include an alkyl group and an allyl group, but an alkyl group is preferable from the viewpoint of safety. Of these, a butyl group and an octyl group are most preferably used from the viewpoint of ease of handling and availability.

Next, OR ⁵ which is a hydrolyzable group will be described. OR ⁵ is not particularly limited as long as hydrolysis is possible, and among them, a carboxy group and a lower alkoxy group are preferably used. As a carboxy group, hydrolysis with moisture in the air easily occurs at room temperature, and since it is commercially available, it has moderate reactivity as an acetoxy group, a lauroxy group, and a chelate group. Therefore, a malate group is preferable.

  Examples of specific representative compounds preferably used as the bifunctional organotin compound include dibutyltin diacetate, dibutyltin dilaurate, dioctyltin diacetate, dioctyltin dilaurate, dibutyltin malate, dioctyltin malate, and the like. It is done. Among them, dibutyltin dilaurate and dioctyltin dilaurate are preferable curing agents because they do not deteriorate curability and do not generate an acetic acid odor at the time of coating. Furthermore, dioctyltin dilaurate is the most preferable curing agent in consideration of raw material supply and toxicity.

As an aluminum compound, as a curing agent having an excellent balance between curability and safety, aluminum trialkoxide such as aluminum triisopropoxide and aluminum tributoxide, aluminum trisacetylacetonate, aluminum trisethylacetoacetate, aluminum bisethyl Examples thereof include aluminum chelate compounds such as acetoacetate monoacetylacetonate, aluminum alkyl acetoacetate diisopropylate, and aluminum ethylacetoacetate diisopropylate. In particular, an aluminum chelate compound is preferable because it is excellent in storage stability of the paint, and aluminum trisacetylacetonate and aluminum trisethylacetoacetate are most preferable from the viewpoint of easy handling.

These metal compound-based curing agents may be used alone or in combination of two or more. In the combination of two or more kinds, a combination of different compounds such as a bifunctional organotin compound and an aluminum chelate compound can be mentioned as a preferred embodiment.

The trifunctional silane compound of component (2) and / or its partially hydrolyzed condensate used in the present invention is the first useful coating film when used in combination with the metal compound curing agent of component (3). Can be formed. That is, a solid three-dimensional cross-linked structure can be obtained without containing any of the trifunctional silane compound as component (2) and / or its partially hydrolyzed condensate and the metal compound curing agent as component (3). do not become.

Whether or not it has a strong three-dimensional crosslinked structure depends on whether it is immersed in a solvent capable of dissolving component (1) and component (2), such as isopar E, which is an isoparaffinic hydrocarbon solvent, at room temperature for several hours or more. This can be confirmed by measuring the residual solid content or the water repellency of the coating film, and the former is generally called a gel fraction.

In order to obtain high durability, the gel fraction should be 60% or more, more preferably 70% or more, and the water contact angle retention should be 90% or more, more preferably 95% or more. desirable.

In addition, the addition composition ratio of each component of the trifunctional silane compound and / or its partially hydrolyzed condensate as the component (2) and the metal compound-based curing agent as the component (3) depends on the type of the component (1) Although it should be experimentally determined by the composition weight ratio, the composition addition weight ratio ((trifunctional silane compound and / or partial hydrolysis condensate thereof) / metal compound curing agent) is usually 1/1. It is preferable to be in the range of ˜700 / 1.

  That is, when the weight ratio of the trifunctional silane compound and / or its partially hydrolyzed condensate and the metal compound-based curing agent is less than 1/1, the crosslinking degree tends to be inferior, and a coating film having excellent weather resistance is obtained. It becomes difficult. In addition, when the addition weight ratio of the trifunctional silane compound and / or its partially hydrolyzed condensate and the metal compound-based curing agent exceeds 700/1, the curing becomes insufficient and the degree of three-dimensional crosslinking decreases. The durability tends to be inferior, such as a decrease in water repellency due to wear or solvent immersion.

  More preferable addition weight ratio is 3/1 to 550/1, more preferably 4/1 to 500/1, since the balance between durability and wear resistance such as water repellency and weather resistance is most easily obtained. Used.

In addition, the crosslinking agent comprising the trifunctional silane compound of component (2) and / or its partially hydrolyzed condensate and the bifunctional organotin compound of component (3) has stability as a paint, after curing. From the viewpoint of improving the water repellency of the coating film and the compatibility with the component (1), a compound having active protons such as moisture and alcohol is contained as long as the progress of three-dimensionalization in the coating is within a controllable range. There is no problem. In general, the trifunctional silane compound is highly volatile, and in some cases, it is preferable that the trifunctional silane compound is hydrolyzed with a small amount of water and further condensed in order to obtain a coating film having stable performance.

Next, component (4) of the present invention will be described. The water-repellent coating agent of the present invention is stored and used in a state in which the component (1), the component (2) and the component (3) are diluted with the solvent which is the component (4). Mixable organic compounds are applied.

In the water-repellent coating agent of the present invention, a dimethyl silicone polymer having a silanol group at both ends and having a number average molecular weight (Mn) of 50,000 to 200,000 is used as the component (1). The viscosity increases as the number average molecular weight increases. Therefore, it is practically impossible to make a paint in a solvent-free system, and it is not practical. Therefore, it is used by diluting with a solvent from the viewpoint of uniform coating and stability of paint.

Since the water-repellent coating agent of the present invention is usually used under mild conditions such as a room temperature environment, at least 50 wt% of the solvent has a boiling point of 60 ° C. to 300 ° C. at 1 atmosphere, more preferably A relatively highly volatile solvent having a temperature of 70 ° C. to 250 ° C. is preferable.

In addition, since the trifunctional silane compound and / or its partially hydrolyzed condensate, which is the component (2) of the present invention, is highly reactive with compounds having active protons such as water and alcohol, the main solvent is a paint. In order to maintain the stability of the coating film and improve the durability of the coating film, a compound which is inactive with respect to the component (2) and the component (3) having no active proton is preferably used.

However, by reacting a material having an active proton such as water or alcohol with the acetoxy group or alkoxy group of component (2), the component (2) compound is modified and at the same time reaction products such as organic acid and alcohol Can also be used as part of the solvent.

  Typical main solvents that can be used include ether compounds, ester compounds, aliphatic hydrocarbon compounds, aromatic hydrocarbon compounds, ketone compounds, and organic halide compounds. Of these, ether compounds, ester compounds, and aliphatic hydrocarbon compounds are preferred from the standpoint of safety.

Specific examples of the ether compound include dipropyl ether, dibutyl ether, diamyl ether and the like.

Specific examples of the ester compound include ethyl acetate, propyl acetate, butyl acetate, amyl acetate, isoamyl acetate, heptyl acetate, ethyl butyrate, isoamyl isovalerate and the like.

Specific examples of the aliphatic hydrocarbon compound include normal heptane, normal octane, normal nonane, and normal decane.

Specific examples of the aromatic hydrocarbon compound include toluene, xylene, dimethylbenzene, trimethylbenzene, and ethylbenzene.

Specific examples of the ketone compound include methyl ethyl ketone and methyl isobutyl ketone.

Specific examples of the organic halide compounds include trichloroethane and trichlorethylene.

Considering that the present invention is often used in an open system in a natural environment, aromatic ethyl acetate, propyl acetate, butyl acetate, amyl acetate, isoamyl acetate, heptyl acetate, ethyl butyrate, isoamyl isovalerate A solvent comprising an ester system such as

On the other hand, aliphatic hydrocarbon compounds having a low odor and low toxicity are particularly useful solvents for workers sensitive to odor. Such aliphatic hydrocarbon compounds include Isopar E, G, H, L, M, V, which is a mixture of isoparaffinic hydrocarbon compounds having several boiling points, or Exol D30, D40, which is a mixture of naphthenic compounds. , D60, D80, D110, D130 and mineral spirits.

These solvents may be used alone or in combination of two or more without any problem. In particular, organic acids such as formic acid, acetic acid, propionic acid, benzoic acid, lauric acid and stearic acid as well as lower alcohols such as methanol, ethanol, propyl alcohol and butanol are provided so that the paint is not clouded or separated into two layers. It is also useful to add the above as a coating solvent because it can improve the storage stability of the coating. In particular, when alcohol is added, if the trifunctional silane compound has an alkoxy group, it is equivalent to the hydrolysis functional group or the addition of a lower alcohol does not lower the reactivity after coating, and the storage stability of the paint is reduced. It is preferable because it is effective in improving the property.

Furthermore, methanol, ethanol, propanol, isopropanol, etc. in a solvent are used to produce organic acids such as formic acid, acetic acid, propionic acid, benzoic acid, lauric acid, stearic acid by reaction with acyloxysilane described above. It is also possible to add an appropriate amount of butanol, or an alcohol having a relatively high boiling point such as propylene glycol monomethyl ether or propylene glycol monoethyl ether to the solvent.

As the organic acid or alcohol used as a part of the solvent, acetic acid and methanol are preferably used since the balance between the stability of the coating and the curability is excellent. The content is preferably in the range of 2 mol to 500 mol with respect to 1 mol of the metal compound-based curing agent of component (3). More preferably, it is used in the range of 10 mol to 350 mol.

  In addition, the trifunctional silane compound of the component (2) of the present invention has a relatively low boiling point depending on the type of the alkoxy group, has volatility, and has excellent compatibility with the component (1). These trifunctional silane compounds can also be used as part of the solvent.

The solvent content is defined as the solid content, but in order to ensure the stability of the paint, to ensure the film thickness necessary to obtain sufficient water repellency, and to obtain a uniform coating film without spots, However, the solid content is usually used in the range of 0.5 wt% to 30 wt%. In particular, 3.5 wt% to 27.5 wt% is preferably used in order to ensure slipperiness of the coating film surface in addition to water repellency. Furthermore, in order to ensure performance including durability, 5 wt% to 25 wt% is more preferably used. The solid content applicable to various coating methods and coating conditions is most preferably in the range of 5.5 wt% to 20 wt%.

The solid content measurement is difficult to define strictly because the present invention is used under mild conditions such as in a natural environment, but usually a small amount of coating agent is poured into a container such as an aluminum cup. The remaining weight after being left under the use conditions can be measured, and the solid content can be obtained with a value reaching a certain value. It is also possible to heat in a dryer or the like for the purpose of shortening the measurement time. As a measurement condition in production management, it is possible to obtain a time during which the remaining weight becomes constant at 100 ° C. and use this condition to obtain a solid content.

Since the component (1) of the present invention has substantially no volatility, its solid content is 100%. However, the solid content of the trifunctional silane compound of the present invention component (2) and / or its partially hydrolyzed condensate and the metal compound curing agent of component (3) is determined by the moisture in the air. It is conceivable that at least a part of it hydrolyzes and then reacts with the component (1), so that it is realistic to obtain a solid value with a constant value obtained after the reaction.

The water-repellent coating agent of the present invention can be stored and used as a composition comprising component (1), component (2), component (3) and component (4), but for the purpose of preventing deterioration during storage, Before use, prepare two solutions of a solution containing component (1), component (2) and component (4) as a main component and a curing agent component solution composed of component (3) and component (4). A more stable coating agent by mixing is also a preferred embodiment in practical use.

In the water-repellent coating agent of the present invention, as a coating film forming component other than the component (1), the component (2) and the component (3), silanols are present at both ends having a number average molecular weight (Mn) of less than 50,000. In addition to dimethylsilicone polymers having a group, and phenyl group and trifluoropropyl group-containing silicone polymers, there are many materials that can be added, such as tetrafunctional silane compounds, bifunctional silane compounds, and various surfactants. .

In particular, tetrafunctional silane compounds can be used in combination within a range that does not significantly reduce water repellency for the purpose of further improving the adhesion and hardness with the substrate. Specific examples of representative compounds include tetraacetoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetrasec-butoxysilane, and partial hydrolysis of such tetrafunctional silane compounds. Examples include decomposition condensates.

In addition, bifunctional silane compounds may be mentioned as additives that are effective for controlling the curing rate for the purpose of improving the wiping property during coating. Specific examples of the silane compound include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, dimethyldiacetoxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, methylethyldipropoxysilane, Methylethyldibutoxysilane, methylethyldiacetoxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, methylpropyldipropoxysilane, methylpropyldibutoxysilane, methylpropyldiacetoxysilane, methylphenyldimethoxysilane, methylphenyldimethoxysilane , Methylphenyldiethoxysilane, methylphenyldipropoxysilane, methylphenyldibutoxysilane, methylphenyldiase Kishishiran and the like. Among them, a dimethylsilane compound is preferably used because it does not lower the water repellency.

These tetrafunctional silane compounds and bifunctional silane compounds can be used simply by mixing them with trifunctional silane compounds. However, when using the trifunctional silane compound as a partial hydrolysis condensate, each of them should be homogeneous in advance. It is a useful means for improving the uniformity as a coating material by preparing a mixed solution and then hydrolyzing / dehydrating and condensing it into a co-condensation partial hydrolysis-condensation product.

In the water-repellent coating agent of the present invention, various surfactants are preferably used for the purpose of improving the wettability to the substrate and the smoothness of the coating film. As the surfactant, one or more selected from fluorine leveling agents, silicone leveling agents, polymer ether leveling agents, nonionic leveling agents and the like that can be dissolved in the solvent of the component (3) of the present invention. Is preferably used.

In particular, a fluorine leveling agent is preferably used as a material that can enhance the surface active effect without lowering the water repellency of the coating film. For example, Megafac F-554 (manufactured by DIC) is preferable. As an agent.

Further, the addition amount of various surfactants is desirably 10 ppm to 10 ⁴ ppm with respect to the water-repellent coating agent of the present invention. If it is less than 10 ppm, the effect of adding to the leveling property of the surfactant is small, and if it exceeds 10 ⁴ ppm, the surfactant tends to bleed out to the surface and the finger touch tends to decrease.

The water-repellent coating agent of the present invention can be cured easily by simply leaving it under room temperature conditions without applying a special curing treatment device after application to the substrate surface. As specific temperature conditions, a temperature at which the solvent can be volatilized is sufficient, but usually 5 ° C. or higher, preferably 10 ° C. or higher is recommended as a practical temperature condition. It is also a preferred embodiment to heat in order to shorten the curing time or to apply wind to speed up drying.

Next, another surface friction coefficient according to the present invention will be described. As a practical evaluation of surface friction, it is possible to qualitatively measure good and bad by rubbing lightly with human fingers or nails, etc., but the surface is used as a method to eliminate arbitraryness It is a coefficient of friction. The surface friction coefficient can be measured quantitatively with good reproducibility by using TRIBOGEAR (manufactured by HEIDON) TYPE: 14FW as a measuring device.

The surface friction coefficient includes a static friction coefficient and a dynamic friction coefficient. In the present invention, the surface friction coefficient of the coating film is determined by using a dynamic friction coefficient having a high correlation with the dirt removal property of the coating film.

Furthermore, as a material used at the time of friction, 100% polyester ultra-fine fiber knitted fabric known to be effective for removing fine dust (“Toraysee” manufactured by Toray Industries, Ltd., basis weight: 275 g / m ² , thickness: 0.75mm) is cut into a 34mm x 105mm square, and a new cloth is used for each measurement to increase the reliability of measurement. The measurement conditions were three times at a room temperature of 23 ° C. ± 2 ° C., a vertical load of 100 g, and a speed of 300 mm / min.

A coating film with a surface friction coefficient exceeding 0.165 is not only difficult to remove when removing dust and dirt, but it is difficult to remove the dirt, resulting in damage to the paint film. is there.

In order to reduce the surface friction coefficient to 0.165 or less, in addition to the coating agent containing the following components (1), (2) and (3), it is necessary to optimize and control the solid content and the coating method. Must be determined.
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof (3) Metal compound curing agent

The solid content of the coating agent is controlled by the content of the solvent, but in order to make the surface friction coefficient 0.165 or less, the solid content is desirably used in the range of 3.5 wt% to 27 wt%. Further, the solid content applicable to various coating methods and coating conditions is preferably in the range of 5.5 wt% to 20 wt%.

The method for applying the water-repellent coating agent to the substrate is not particularly limited. Specific methods include dipping coating, spray coating, flow coating, brush coating, spin coating, and impregnation with paint. For example, a transfer coating method using a cloth or a sponge, and the like should be selected as appropriate depending on the size and shape of the substrate.

Furthermore, another method for producing a coating film according to the present invention will be described. That is, the present invention is a method for producing a water-repellent coating film in which a water-repellent coating agent is applied and then spread using a cloth made of ultrafine long fibers. Particularly preferable coating agents include water-repellent coating agents containing the following components (1) to (4).
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof (3) Metal compound curing agent ( 4) Solvent

As an application method of the water-repellent coating agent of the present invention, an article having an irregular shape such as a molded product is not subjected to a brush coating method, a transfer coating method using a cloth or sponge impregnated with a paint, or a spray coating to eliminate a non-coated portion. Is preferable.

In particular, as a method to ensure the uniformity and smoothness of the coating film, brush coating, transfer coating with a cloth or sponge impregnated with paint, or ultra-fine long fibers that enable thin film coating after spray coating A method of spreading using a cloth made of is recommended as a method for obtaining a practical and good appearance.

Here, examples of the form of the cloth made of ultrafine long fibers include woven fabrics and knittings made of yarn generally called microfibers, and there is no problem whether it is a sheet or a towel. Furthermore, as the woven fabric, a double woven fabric in which the front and back are knotted, or a so-called twill woven fabric in which the warp is woven by crossing the top and bottom of the weft, and a woven fabric composed of five or more warps and wefts. There is a satin weave. In particular, when a coating film formed by transferring a large amount of paint is applied, a cloth having a woven fabric in a towel shape is preferably used.

In addition, as fabric materials used for spreading, natural fibers, synthetic fibers, blended fibers of natural fibers and synthetic fibers, and fibers in which two or more synthetic fibers such as polyester and polyamide are combined are also used. can do. In particular, synthetic fibers are most preferable because fibers having a sea-island structure or fibers having a split structure can be made very fine. Furthermore, the fiber diameter is preferably 1.0 μm to 7.5 μm for uniform coating thickness. In particular, the fiber diameter that is more desirable for uniform coating thickness is preferably 1.5 μm to 7.0 μm.

Since the water-repellent coating agent of the present invention has hydrophobicity and is accelerated by moisture in the air, it is soluble after simultaneously spinning a 100% polyester material and a polymer soluble in an organic solvent. The ultra-fine long fibers consisting of the so-called sea-island structure with the polymer component dissolved and removed are not only preferable because they are excellent in imparting surface uniformity of the membrane, but also useful for improving durability. Is preferably used.

In addition, for example, in a water-repellent coating agent in which a high molecular weight dimethyl silicone polymer having silanol groups at both ends and having a number average molecular weight (Mn) of 50,000 to 200,000 is used as a main component, the coating agent is a cloth material at the time of spreading. Since it does not easily penetrate to the inside of the cloth, it tends to spread while attached to the cloth surface.

Therefore, when applying to a large area substrate, etc., in order to make the spreading smoothly, the initial stage where a large amount of coating agent is attached is the ultrafine fiber having a split structure that is easy to adsorb and remove the coating agent. A two-stage spreading method using an ultrafine fiber made of a sea-island structure with a flat surface for application and final finishing is preferred.

It is also useful to use a cloth impregnated with moisture for spreading for the purpose of accelerating curing by moisture. If the amount of water to be impregnated is such that water drops do not fall even when squeezed, a sufficient effect is expected.

Furthermore, it is possible to include a small amount of acid or base in the water. Specifically, water containing a volatile acid compound such as dilute hydrochloric acid or dilute acetic acid makes the hydrolysis after spreading smoother. It is preferably used because of its ability to proceed.

Since the water-repellent coating film of the present invention has a structure in which dimethyl silicone polymer is three-dimensionally crosslinked, its refractive index is relatively low, and thus it is possible to reduce light reflection and to have deep glossiness. There is also.

However, if the coating film becomes too thick, stripes and smears due to light interference tend to be noticeable and tend to be inferior in design. Further, when the coating film is too thin, not only the water repellency effect tends to be lowered, but also the surface slipperiness tends to be lowered. In addition, the effect of filling the scratches on the substrate to be coated is small, and the expression of deep gloss due to the reduction of light reflection tends to decrease.

Therefore, the film thickness of the coating film obtained from the water-repellent coating agent of the present invention is thinner than the visible light wavelength, 4 nm to 200 nm, more preferably 6 nm to 100 nm, more preferably 8 nm to the film thickness necessary for ensuring water repellency. 80nm is recommended.

  The water-repellent coating agent of the present invention has sufficient wear resistance, surface coating slipperiness, weather resistance, chemical resistance, etc., simply by applying it to a substrate and then curing it by natural drying in a room temperature environment. It becomes a water-repellent coating film.

As the curing condition of the water-repellent coating agent of the present invention, it can be sufficiently cured under normal natural environmental conditions, but as a measure to further increase the water repellency, in a high humidity environment, specifically 20% RH, more preferably Is preferably cured in a humidity environment of 30% RH or higher. As a means for increasing the humidity, a method of spreading water or warm water on the floor or a water mist spraying can be mentioned as a simple and effective method.

As a method for shortening the curing time of the water-repellent coating agent of the present invention, it is also effective to increase the temperature of the vehicle body including the bonnet by blowing air to speed up drying, or by applying a car engine when applied to a car. As a method.

  The coating film obtained by the water-repellent coating agent of the present invention has high water repellency and is excellent in durability, slipperiness, and abrasion resistance. Therefore, it is usually rubbed with human hands and fingers, cloths and papers, etc. It is preferably applied to applications that are often applied, or applications where rainwater or tap water falls.

  Although the chemical reaction of the curing reaction of the water-repellent coating agent of the present invention has not been fully elucidated, the trifunctionality in which both end silanol groups of the dimethyl silicone polymer are basically crosslinking agents It is presumed that the silane compound and / or the hydrolysis product of the partially hydrolyzed condensate thereof has a structure obtained by reacting directly or indirectly with the metal compound curing agent.

That is, it is considered that a dimethyl silicone polymer having both terminal silanol groups having a high number average molecular weight (Mn) exhibits good characteristics by forming a crosslinked structure three-dimensionally.

  In addition, the details of the hydrolysis and curing reaction scheme of the trifunctional silane compound as component (2) and / or its partial hydrolysis condensate and the metal compound curing agent as component (3) are still determined. However, it is presumed that the reaction is progressing in a complex reaction system.

  The water-repellent coating film of the present invention has low surface energy, excellent water repellency, and the coating film is highly three-dimensionally crosslinked. In addition, it has high durability with excellent wear resistance, weather resistance, chemical resistance and the like.

As a method for evaluating water repellency in the present invention, the most common method is to measure the so-called static contact angle of water formed between the water and the coating film surface by forming minute water droplets on the coating film surface. It is. The static contact angle of water can be measured by using an “automatic contact angle meter” (FACE) CA-Z type as a measuring device.

  The coating film excellent in water repellency in the present invention means a film having a high static contact angle of water, and specifically a film having an initial contact angle higher than that of the substrate to be coated. An example of a film having a higher water repellency is a film having a static contact angle of 100 degrees or more, and an ideal film having a high water repellency is a film having a static contact angle of 102 degrees or more.

That is, a film having a static contact angle of water lower than that of the substrate is meaningless to provide a water-repellent coating film, and in a film having a static contact angle of less than 100 degrees, liquid drinks such as rainwater, purified water, and alcoholic beverages, When it adheres to the film surface, it is difficult to drop from the film surface, and therefore it is not meaningful to provide a water-repellent coating film.

Such a coating film has a problem that water droplets or the like are likely to remain on the surface, not only deteriorating the sense of quality, but also causing a surface appearance defect called rain stain or water burn on the coating film after drying.

  Further, the durability in the present invention is a scale for judging whether or not to withstand long-term use, specifically, the water repellency retention after an outdoor exposure test of one month or more is 90% or more, Furthermore, it means that the water repellency retention after immersion in a solvent in which the silicone component is dissolved, such as isopar E or ethyl acetate, which is an isoparaffinic hydrocarbon, is 90% or more.

As apparent from the above description, the water-repellent coating agent of the present invention contains the following components, and the effects listed below can be obtained.
(1) “Crosslinking agent comprising a dimethyl silicone polymer having a silanol group at both ends (Mn) of 50,000 to 200,000, a trifunctional silane compound and / or a partially hydrolyzed condensate thereof, and a metal compound curing agent. Water-repellent coating agent comprising a solution containing a solvent and a solvent, which forms a water-repellent coating film having excellent slipperiness and durability such as weather resistance and chemical resistance on the surface of various substrates. be able to.

(2) “Coating film having a surface friction coefficient of 0.165 or less of the coating film obtained by the water-repellent coating agent of the above (1)”. It is easy to remove dust and dirt without putting on.

(3) “As a method for producing a coating film using the water-repellent coating agent of (1), a coating film in which a water-repellent coating agent is applied and spread using a cloth made of ultrafine long fibers” A water-repellent coating film having a uniform surface that is simple and free of coating spots can be obtained.

(4) The water-repellent coating film of the present invention has a low refractive index, and in addition to characteristics such as water repellency, abrasion resistance, durability, and slipperiness, it can achieve a deep gloss expression and is excellent in balance. A water-repellent coating film can be obtained.

  Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

(1) Evaluation method (a) Water repellency
The static contact angle (degree) of water was measured using a CA-Z type “automatic contact angle meter” manufactured by FACE, and the value was used as water repellency.
(B) The substrate on which the gloss coating film was applied was irradiated with light, and the gloss due to surface reflection and the depth of the substrate color were examined with the naked eye. Compared with the untreated product, a product with clearly less reflection and good depth was marked with ◯, an equivalent level was marked with Δ, and an inferior one was marked with ×. In addition, the intermediate level of (circle) and (triangle | delta) was displayed as (circle)-(triangle | delta).
(C) Abrasion resistance The surface of the coating film was rubbed with the tip of the middle finger of a human to examine the occurrence of scratches.
○: Slightly less scratches than untreated products.
Δ: Scratches at the same level as untreated products occur.
X: More scratches than untreated products. Or a sticky level.
In addition, the intermediate level of (circle) and (triangle | delta) was displayed as (circle)-(triangle | delta).
(D) Film-forming property The uniformity of the coating film when applied to the test piece substrate described below was evaluated with the naked eye.
○: No spots are observed.
(Triangle | delta): A fine spot is recognized.
X: Occurrence of obvious spots is observed.
In addition, the intermediate level of (circle) and (triangle | delta) was displayed as (circle)-(triangle | delta).
(E) Durability After immersion for 3 days at room temperature in water, the static contact angle of water on the membrane surface after outdoor exposure for 1 month on the south-facing slope, or isopara E, an isoparaffinic hydrocarbon solvent The static contact angle of water was measured and the water repellency retention rate (%) was determined. The higher the retention rate, the better the water repellency durability.
(F) Slip qualitative evaluation method The coating film surface was evaluated by the strength of catching when it was scratched with fingers or nails.
○: Slightly less slipping and better slipperiness than untreated products.
(Triangle | delta): There exists a catch of the same level as an untreated product.
X: Feels a stronger catch than untreated products.
In addition, the intermediate level of (circle) and (triangle | delta) was displayed as (circle)-(triangle | delta).
Quantitative evaluation method TRIBOGEAR (manufactured by HEIDON) TYPE: 14FW, polyester ultra-fine fiber knitted fabric cut to 34mm x 105mm square ("Toraysee" manufactured by Toray Industries, Ltd., basis weight: 275g / m ² , thickness: 0.75 mm) was placed on a horizontal coating film and slid at a vertical load of 100 g and at a speed of 300 mm / min., the kinetic friction coefficient was measured three times. .
Note that the slipperiness of the untreated product was 0.256.
(G) Gel fraction In an open aluminum can, the film cured and adjusted for 3 days at 40 ° C was immersed in a beaker with a large excess of Isopar E at room temperature for 1 week in an airtight state. The gel content was determined by weighing the previous solid content and the remaining solid content after filtration and drying.
(H) Number average molecular weight measurement Using a high-speed GPC apparatus (HLC-8220GPC) manufactured by Tosoh Corporation, measurement was performed using chloroform as a developing solvent.

(Experimental Examples 1-10), (Comparative Examples 1-6)
(1) Coating agent adjustment Dimethylsilicone polymer having silanol groups at both ends of number average molecular weight (Mn) described below and ethyltriacetoxysilane (ETA), dibutyltin diacetate (DBTDA) ) Or dioctyltin diacetate (DOTDA), and a paint having a solvent amount shown in Table 1 was prepared. In Experimental Example 6, Experimental Example 7 and Experimental Example 8, the amount of isoamyl isovarate (ISIS) in the amount of solid content shown in Table 1 was added to the coating material of Experimental Example 5 for adjustment.
DMS-S42 (manufactured by GELEST Inc.): Number average molecular weight 61,000
DMS-S51 (manufactured by GELEST Inc.): Number average molecular weight 120,000
DMS-S31 (manufactured by GELEST Inc.): Number average molecular weight 21,000
DMS-S14 (manufactured by GELEST Inc.): Number average molecular weight 1,600

(2) Preparation of substrate to be coated A 0.1 mm thick tin plate is applied with LV Prasaf made by Isamu Paint Co., Ltd. as a primer, followed by Milan 2K made by Isamu Paint Co., Ltd. As a result, a coated test piece substrate for a water-repellent coating film was created by applying Milan 2K Como Clear No. 1 manufactured by Isamu Paint Co., Ltd.

(3) Coating film adjustment On the substrate to be coated in (2) above, it was applied using a sponge impregnated with a coating agent, and then a 100% polyester sea-island ultrafine fiber knitted fabric ("Toraysee" manufactured by Toray Industries, Inc.) ) And spread to a state without smears, and then allowed to dry naturally in an open state for one week to obtain a coating film.

(4) Evaluation results Table 1 shows the evaluation results of the obtained coating films. The coating film obtained by the water-repellent coating agent of the present invention is uniformly applied on the substrate to be coated because of its excellent film forming property. Furthermore, as shown in Table 1, it has very excellent water repellency and gloss. It became clear that it was excellent in the property, abrasion resistance, slipperiness, and durability (Experimental example 1-Experimental example 9). On the other hand, the coating film using the coating agent containing no crosslinking agent (Comparative Example 1) was sticky, poor in water repellency, and had no practical utility. In addition, a coating film (Comparative Example 2, Comparative Example 3) using a dimethyl silicone polymer having silanol groups at both ends having a number average molecular weight (Mn) of less than 50,000 and a coating agent containing no component (1) were used. The coating film (Comparative Example 4) was a coating film with poor water repellency or poor slipperiness. Incidentally, the water repellency of the uncoated substrate surface was 95 degrees. Furthermore, a coating film (Comparative Example 5) using a coating composition containing no trifunctional silane compound and / or partial hydrolysis condensate thereof in Component (2), and another component in Component (2) The coating film (Comparative Example 6) using a coating agent that does not contain any metal compound-based curing agent is a coating film having a low gel fraction and a problem with durability. On the other hand, it was confirmed that there was no problem even if the metal compound-based curing agent composed of a bifunctional organotin compound was changed from dibutyltin diacetate (DBTDA) to dioctyltin diacetate (DOTDA) (Experimental Example 10).

When the coating material of Example 1 (Experimental Example 4) was applied to the entire surface of the hood of an automobile, the occurrence of faint coating spots was observed in part, but those of Experimental Example 5 to Experimental Example 8 in Example 1 were the same. When the paint was used, a coating film excellent in appearance without any coating spots could be obtained. This is considered to be the effect of including isopropyl alcohol (IPA) in the solvent. That is, when the GC / MS analysis of the trifunctional silane compound used in Experimental Example 5 was performed, it was found that all ethyltriacetoxysilanes were alcohol-substituted, and the monoalcohol-substituted silane was 12 mol%, It was revealed that the dialcohol-substituted silane was 73 mol% and the trialcohol-substituted silane was 15 mol%. In the silane compound substituted with alcohol, acetic acid produced by the substitution reaction in the same molar amount as the amount of alcohol added was detected. The water repellency, glossiness, slipperiness of the coating film surface, durability, etc. of the coating films obtained in the above Experimental Examples 5 to 7 have the same level of characteristics as in Example 1 (Experimental Example 4). It was. Moreover, the coating film obtained by Experimental Example 8 clearly had a slipperiness superior to that of the substrate.

In Example 1 (Experimental Example 4), after wiping in advance with a towel made of ultrafine long fibers soaked with a small amount of water, 100% polyester sea-island type ultrafine fiber knitted fabric (manufactured by Toray Industries, Inc.) When the entire surface of the bonnet was wiped off using Toraysee "), a coating film having an excellent appearance with no coating spots could be obtained. Moreover, the water repellency, glossiness, slipperiness of the coating film surface, durability, etc. of the obtained coating film had the same level of characteristics as in Example 1 (Experimental Example 4).

(1) Paint preparation 3.1 g of ethyltriacetoxysilane in the paint of Example 1 (Experimental Example 4) was changed to 7.25 g of methyltrimethoxysilane, and 28.7 g of isoamyl isovalerate and 1.6 g of methanol were used as solvents. The coating composition was adjusted in the same manner except that it was added to 0.4 g of dioctyltin dilaurate (DOTDL) as a metal compound-based curing agent composed of a bifunctional organotin compound.

(2) When coating was performed on the white bonnet in the same manner as in Example 2, a film free from coating spots and excellent in water repellency and slipperiness could be obtained. In addition, the paint did not generate the odor of acetic acid at the time of coating felt with paints using dibutyltin diacetate (DBTDA) or dioctyltin diacetate (DOTDA), and it was easy to handle for workers. The solid content of the paint was 8.7%.

(1) Paint preparation 7.25 g of methyltrimethoxysilane in the paint of Example 4 was changed to 1.44 g of the following methyltrimethoxysilane partial hydrolysis condensate, and 31.4 g of isoamyl isovalerate and methanol were used as solvents. The coating composition was adjusted in the same manner except that 1.5 g was added and dioctyltin dilaurate (DOTDL) was changed to 0.13 g as a metal compound-based curing agent composed of a bifunctional organotin compound.

(2) Preparation of methyltrimethoxysilane partial hydrolysis condensate 13.6 g of methyltrimethoxysilane was weighed in a beaker, and 1.8 g of 0.01 N hydrochloric acid aqueous solution was added at a time while stirring with a magnetic stirrer at room temperature. After the addition, as the hydrolysis progressed, the opaque solution turned into a clear solution with a slight exotherm. Stirring was continued with the beaker sealed until the solution temperature reached room temperature. When the temperature reached room temperature, stirring was stopped, and the mixture was aged at room temperature overnight to obtain a hydrolyzate. After aging overnight, methanol as a hydrolysis product was removed with an evaporator (45 ° C., 75 mmHg, 30 minutes) to obtain a methyltrimethoxysilane partial hydrolysis condensate.

(3) When coating was performed on the black bonnet in the same manner as in Example 2, a film free from coating spots and excellent in water repellency and slipperiness could be obtained. Further, as in Example 4, the acetic acid odor at the time of coating did not occur at all, and the paint was easy to handle for the operator. The solid content of the paint was 10.2%. Furthermore, it was confirmed that even if the coating material was coated at room temperature after being stored for 3 months, it could be coated in the same manner and had a very excellent paint pot life.

When the coating color of the bonnet was changed from white to black in Example 4, since faint coating spots were confirmed, a 100% polyester sea-island type ultra-fine fiber knitted fabric ("Toraysee" manufactured by Toray Industries, Inc.) was added to the polyester / When the entire bonnet is wiped with a microfiber towel (manufactured by Maruno Towel Co., Ltd., microfiber green towel, No.RO463-1-S) made of split-type ultrafine fiber fabric of nylon = 80% / 20% A coating film having an excellent appearance with no coating spots was obtained. Further, the obtained coating film had good properties such as water repellency, glossiness, and slipperiness of the coating surface.

In Example 6, a microfiber handy cloth made of polyester / nylon split microfiber fabric made of polyester / nylon = 70% / 30% (manufactured by Maruno Towel Co., No. ROC120-3- When the entire surface of the bonnet was wiped up instead of C), a coating film having an excellent appearance with no coating spots was obtained. Further, the obtained coating film had good properties such as water repellency, glossiness, and slipperiness of the coating surface.

When it was applied to the entire roof surface of an automobile in the same manner as in Example 7, slight coating spots were observed in the central portion. Therefore, a microfiber made of a split-type ultrafine fiber fabric composed of polyester / nylon = 70% / 30%. After wiping with Handy Cloth (Maruno Towel Co., Ltd., No.ROC120-3-C), using 100% polyester sea-island type ultra-fine fiber knitting ("Toraysee" manufactured by Toray Industries, Inc.) When the entire roof surface was wiped off, a coating film excellent in appearance with no coating spots could be obtained. Further, the obtained coating film had good properties such as water repellency, glossiness, and slipperiness of the coating surface.

(1) Paint Preparation Example 5 A paint was prepared in the same manner except that isoamyl isovalerate and methanol in the paint were changed to Isopar L, which is an isoparaffinic hydrocarbon of the same weight.

(2) When coating was performed on the black bonnet in the same manner as in Example 6 using the obtained paint, a film free of coating spots and excellent in water repellency and slipperiness could be obtained. Further, as in Example 5, not only the acetic acid odor does not occur at the time of coating, but also the smell of a strong fragrance of isoamyl isovalerate does not occur. The paint was easy to handle.

The water-repellent coating agent of the present invention is suitable for obtaining a coating film excellent in water repellency, slipperiness and abrasion resistance on various substrate surfaces. In particular, since the water-repellent coating film of the present invention is stable against light and heat, it has high durability, and further becomes a coating film excellent in deep glossiness. Moreover, it can be cured in a room temperature environment, and further has a feature that the selection range of the coating method is large and the degree of freedom is large. In addition to these coating characteristics, the coating film is transparent and has excellent water repellency, so it has windows and exterior parts for vehicles such as trains, cars, and buses, as well as the outer walls of buildings and general houses, window glass, etc. It can also be applied to. It can also be applied to painted metal parts such as vehicle wheels.

Claims (18)

A water repellent coating agent comprising the following components (1) to (4):
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof (3) Metal compound curing agent ( 4) Solvent The water repellent coating agent according to claim 1, wherein the component (2) crosslinking agent contains 5 to 1,000 parts by weight with respect to 100 parts by weight of the component (1). Component (2) is a composition comprising a trifunctional silane compound and / or a partially hydrolyzed condensate thereof and a metal compound-based curing agent (3) added at a weight ratio of 1/1 to 700/1. The water-repellent coating agent according to claim 1 or 2, wherein the water-repellent coating agent is provided. The trifunctional silane compound of component (2) and / or its partial hydrolysis condensate is a trifunctional silane compound having a C 1-3 alkyl group or alkenyl group and / or its partial hydrolysis condensate. The water-repellent coating agent according to claim 1, 2 or 3. The functional group in the trifunctional silane compound of component (2) and / or its partial hydrolysis-condensation product is one or more selected from an alkoxy group having 1 to 2 carbon atoms or an acetoxy group, The water-repellent coating agent according to claim 2, 3 or 4. The metal compound-based curing agent of component (3) is at least one selected from bifunctional organotin compounds having a hydrocarbon group having 2 to 12 carbon atoms and aluminum triskillate compounds. The water repellent coating agent according to claim 2, claim 3, claim 4 or claim 5. The solvent of the component (4) comprises an amount of 3 wt% to 30 wt% as a solid content of the coating material, characterized in that it comprises 3 wt% to 30 wt%. 6. The water-repellent coating agent according to 6. 50% by weight or more of the solvent of component (4) has a boiling point of 60 ° C. to 250 ° C., claim 1, claim 3, claim 4, claim 5, claim 6 or claim 6 Item 8. The water-repellent coating agent according to Item 7. A coating film obtained by curing the coating agent according to any one of claims 1 to 8, wherein the surface friction coefficient of the film is 0.165 or less. A method for producing a water-repellent coating film, characterized in that, in the coating film forming method using a water-repellent coating agent, a cloth composed of long fibers having a fiber diameter of 1.0 μm to 7.5 μm is spread. The method for producing a water-repellent coating film according to claim 10, wherein the water-repellent coating agent comprises the following components (1) to (4).
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof (3) Metal compound curing agent ( 4) Solvent The method for producing a water-repellent coating film according to claim 10 or 11, wherein the cloth made of long fibers is a cloth made of polyester synthetic fibers. The method for producing a water-repellent coating film according to claim 12, wherein the synthetic fiber made of polyester is a cloth made of 100% polyester synthetic fiber. In the method of spreading using a cloth made of long fibers in the coating film forming method using a water-repellent coating agent, the cloth is first spread using cloth made of split-type structured ultrafine fibers having a fiber diameter of 1.0 μm to 7.5 μm. A method for producing a water-repellent coating film, characterized in that, after stretching, a fabric made of sea-island-type ultrafine fibers is further spread. The method for producing a water-repellent coating film according to claim 14, wherein the water-repellent coating agent comprises the following components (1) to (4).
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof (3) Metal compound curing agent ( 4) Solvent 16. The method for producing a water-repellent coating film according to claim 14 or 15, wherein the cloth composed of split-type structured ultrafine fibers is a woven fabric. The method for producing a water-repellent coating film according to claim 14 or 15, wherein the cloth made of sea-island-type ultrafine fibers is a knitted fabric. A water repellent coating agent is mixed with a stock solution containing the following components (1), (2) and (4) and a stock solution containing the following components (3) and (4) before use. Water repellent coating agent.
(1) Dimethyl silicone polymer having silanol groups at both ends and a number average molecular weight (Mn) of 50,000 to 200,000 (2) Trifunctional silane compound and / or partial hydrolysis condensate thereof (3) Metal compound curing agent ( 4) Solvent