TWI862773B - Water-repellent oil-repellent coating composition and applications thereof - Google Patents

Abstract

The subject of the present invention is to provide a coating composition, which is a coating composition containing an organic silane compound having an amino group and a boron compound, which can maintain excellent properties such as high hardness while taking into account the water repellency and oil repellency of the cured coating at a high level. The solution of the present invention is a coating composition, which contains the following components (a), (b) and (c): (a) a silane compound containing an amino group represented by the following formula (I): (wherein, R represents an organic group containing an amine group, R' represents a methyl group, an ethyl group or a propyl group, and n represents an integer selected from 1 to 3); (b) at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O ₃ ; (c) a fluorine-containing compound represented by the following formula (II); (In the above formula (II), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group, x is an integer of 1 to 100, and y is an integer of 0 to 100).

Description

Water-repellent and oil-repellent coating composition and use thereof

The present invention relates to a coating composition containing an organosilane compound having an amino group, a boron compound and a specific fluorine compound and its use, and more particularly, to the coating composition having excellent water repellency and oil repellency and its use.

The polymer obtained by reacting an organic silane compound with a boron compound can take into account the advantages of both inorganic and organic materials. More specifically, it can be designed to have high hardness, crack prevention, transparency, heat resistance, chemical resistance, etc. according to the application, so it can be applied to various uses such as coating materials, paints, adhesives, glass substrates, fillers, etc.

In particular, the polymer obtained by reacting an organosilane compound having an amino group with a specific boron compound can be formed in a relatively short time without the need for the complicated steps of hydrolysis required by the melt-gel method, and has excellent properties such as being applicable to one-liquid room-temperature curable materials (for example, see Patent Document 1). In addition, it has been reported that the above-mentioned organosilane compound having an amino group and a specific boron compound can obtain a film having good hard coating properties and good adhesion to metal even when dried at room temperature and humidity by further combining metal alkoxide and lithium, and it is proposed to be applied not only to metals but also as a coating agent for glass, ceramics, plastics, etc. (for example, see Patent Document 2).

In coating applications, from the perspective of antifouling properties, water repellency and oil repellency are required. Depending on the specific application of the coating, the use environment, etc., there are cases where both water repellency and oil repellency are required, but there are few coating agents that have both water repellency and oil repellency. There is a strong demand for coating agents that can take these into account at a high level. [Prior art literature] [Patent literature]

[Patent Document 1] International Publication No. 2006/129695 [Patent Document 2] Japanese Patent Publication No. 2011-26473

[The problem that the invention is trying to solve]

In view of the above-mentioned strong requirements for water repellency and oil repellency and the limitations of the known technology, the subject of the present invention is to provide a coating composition, which is a coating composition containing an organic silane compound having an amino group and a boron compound, which can maintain excellent properties such as high hardness while taking into account the water repellency and oil repellency of the cured coating at a high level. [Means for solving the problem]

As a result of their dedicated research, the inventors of the present invention have discovered that the combination of an organic silane compound having an amino group and a boron compound having a specific structure, and further the combination of a fluorine-containing compound having a specific structure, can achieve a high level that exceeds the limits of the conventional technology, taking into account both the water repellency and oil repellency of the coating, and better still maintaining the coating's excellent properties such as high hardness and transparency, and have finally completed the present invention. That is, the present invention relates to: [1] A coating composition comprising the following components (a), (b) and (c): (a) an amino-containing silane compound represented by the following formula (I): (wherein, R represents an organic group containing an amine group, R' represents a methyl group, an ethyl group or a propyl group, and n represents an integer selected from 1 to 3); (b) at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O ₃ ; (c) a fluorine-containing compound represented by the following formula (II); (In the above formula (II), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group, x is an integer of 1 to 100, and y is an integer of 0 to 100).

In addition, the following [2] to [16] are all preferred aspects or embodiments of the present invention. [2] The coating composition as described in [1], further comprising (d) an organic solvent. [3] The coating composition as described in [2], wherein the aforementioned (d) organic solvent comprises an alcohol having 1 to 5 carbon atoms. [4] The coating composition as described in [2], wherein the aforementioned (d) organic solvent comprises a branched alcohol having 3 to 5 carbon atoms. [5] The coating composition as described in any one of [2] to [4], wherein the aforementioned (d) organic solvent is contained in an amount of 20% by mass or more. [6] A coating composition as described in any one of [1] to [5], further comprising (e) a metal alkoxide (except for components (a) or (c)). [7] A coating composition as described in any one of [1] to [6], further comprising (g) an epoxy resin. [8] A method for producing a coating layer, comprising the steps of reacting the following components (a), (b) and (c): (a) a silane compound containing an amino group represented by the following formula (I): (wherein, R represents an organic group containing an amine group, R' represents a methyl group, an ethyl group or a propyl group, and n represents an integer selected from 1 to 3); (b) at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O ₃ ; (c) a fluorine-containing compound represented by the following formula (II); (In the above formula (II), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group, x is an integer from 1 to 100, and y is an integer from 0 to 100). [9] The method for producing a coating layer as described in [8], wherein the aforementioned step is carried out in an organic solvent (d). [10] The method for producing a coating layer as described in [9], wherein the aforementioned organic solvent (d) contains an alcohol having 1 to 5 carbon atoms. [11] The method for producing a coating layer as described in [9], wherein the aforementioned organic solvent (d) contains a branched alcohol having 3 to 5 carbon atoms. [12] The method for producing a coating layer as described in any one of [9] to [11], wherein the aforementioned step is carried out in a composition containing 20% by mass or more of (d) an organic solvent. [13] The method for producing a coating layer as described in any one of [8] to [12], wherein in the aforementioned step, the components (a), (b) and (c) are further reacted with (e) a metal alkoxide (except for components (a) or (c)). [14] The method for producing a coating layer as described in any one of [8] to [13], wherein in the aforementioned step, the components (a), (b) and (c) are further reacted with (g) an epoxy resin. [15] A method for producing a coating layer, comprising the step of coating a coating composition as described in any one of [1] to [7]. [16] A method for producing a coating layer as described in any one of [8] to [15], wherein the coating layer is formed on a metal substrate, a glass substrate, a wood substrate or a ceramic substrate. [Effect of the Invention]

According to the present invention, a coating composition that can take into account both the water repellency and oil repellency of the coating after curing at a high level, and a coating composition manufacturing method, etc. can be provided. The coating composition can take into account both the water repellency and oil repellency of the coating obtained therefrom at a high level exceeding the limit of the conventional technology, and can preferably maintain the excellent properties such as high hardness and transparency of the polymer obtained by the reaction of an organic silane compound and a boron compound, so it is particularly suitable for coating components such as building interior materials or exterior wall materials that are exposed to both water-soluble dirt and oily dirt.

[Form of implementing the invention]

The present invention is a coating composition comprising the following components (a), (b) and (c): (a) an amino-containing silane compound represented by the following formula (I): (wherein, R represents an organic group containing an amine group, R' represents a methyl group, an ethyl group or a propyl group, and n represents an integer selected from 1 to 3); (b) at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O ₃ ; (c) a fluorine-containing compound represented by the following formula (II); (In the above formula (II), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group, x is an integer of 1 to 100, and y is an integer of 0 to 100).

That is, the coating composition of the present invention is a composition containing the above-mentioned (a) component (silane compound containing an amino group), (b) component (boron compound) and (c) component (fluorine-containing compound having a specific chemical structure). The coating layer obtained by curing the coating composition of the present invention usually contains a compound containing a chemical structure obtained by reacting these (a) to (c) components in at least a part thereof. In addition, the coating composition of the present invention may also be a part of the reaction of (a) to (c) components before curing, and may also contain a part of the reaction products of (a) to (c) components. The chemical structure obtained by reacting the above-mentioned (a) component (silane compound containing an amino group), (b) component (boron compound) and (c) component (fluorine-containing compound having a specific chemical structure) forms a polymer structure in most cases. Typically, the (b) boron compound acts as a crosslinking agent through the amino group in the (a) silane compound containing an amino group, so that these components are polymerized to form a polymer structure having constituent units derived from the (b) boron compound and constituent units derived from the (b) boron compound. That is, the coating composition of this preferred embodiment is a combination of the (a) component and the (b) component that can form a reaction product having a polymer structure under the condition of 10 to 50°C. That is, the reaction product contains a polymer structure having constituent units derived from the (a) component and constituent units derived from the (b) component. In this polymer structure, the ratio of the constituent units derived from component (a) to the constituent units derived from component (b) is preferably 0.02 mol or more of the constituent units derived from component (b) per 1 mol of the constituent units derived from component (a).

Furthermore, in this embodiment, it is preferred that the polymer structure having the constituent units derived from the component (a) and the constituent units derived from the component (b) is modified by the fluorine-containing compound of the component (c). However, the reaction product may also have a structure other than this, for example, a structure in which the constituent units derived from the fluorine-containing compound of the component (c) are incorporated into the polymer structure having the constituent units derived from the component (a) and the constituent units derived from the component (b).

(a) Silane Compound Containing an Amino Group The component (a) used in the present invention is a silane compound containing an amino group and has a specific structure represented by the following formula. (In the formula, R represents an organic group containing an amino group, R' represents a methyl group, an ethyl group or a propyl group, and n represents an integer selected from 1 to 3).

Here, R represents an organic group containing an amino group, for example, monoaminomethyl, diaminomethyl, triaminomethyl, monoaminoethyl, diaminoethyl, triaminoethyl, monoaminopropyl, diaminopropyl, triaminopropyl, monoaminobutyl, diaminobutyl, triaminobutyl and organic groups having an alkyl or aryl group with a greater number of carbon atoms than these, but not limited thereto. Particularly preferred is γ-aminopropyl or aminoethylaminopropyl, and most preferred is γ-aminopropyl.

R' in the component (a) represents a methyl group, an ethyl group or a propyl group, among which a methyl group and an ethyl group are preferred.

In the component (a), n represents an integer selected from 1 to 3. Among them, n is preferably 2 to 3, and n is particularly preferably 3. Therefore, as the component (a), γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, etc. are particularly preferred.

(b) Boron Compound The component (b) used in the present invention is at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O _3. The component (b) is preferably H ₃ BO ₃ .

The amount of the two components used in the reaction of component (a) and component (b) is preferably 0.02 mol or more of component (b) relative to 1 mol of component (a), more preferably 0.02 mol to 8 mol of component (b) relative to 1 mol of component (a), and particularly preferably 0.02 mol to 5 mol. Since the amount of component (b) is 0.02 mol or more relative to 1 mol of component (a), problems such as excessively long curing time or insufficient curing can be effectively suppressed. In addition, since the amount of component (b) is 8 mol or less relative to 1 mol of component (a), problems such as component (b) not dissolving in component (a) and remaining can be effectively suppressed.

The mixing conditions (temperature, mixing time, mixing method, etc.) when reacting (a) the silane compound containing an amino group and (b) the boron compound can be appropriately selected. Under normal room temperature conditions, it becomes a transparent and viscous liquid and solidifies in a few minutes to tens of minutes. Since the curing time or the viscosity or rigidity of the obtained reaction product also varies depending on the proportion of the boron compound, it is better to adjust these conditions appropriately according to the physical properties of the reaction product to be obtained or the purpose of use.

The boron compound (b) is preferably used in the form of a boron compound alcohol solution dissolved in an alcohol having 1 to 7 carbon atoms. Examples of the alcohol having 1 to 7 carbon atoms include methanol, ethanol, various propanols, various butanols, and glycerol, and methanol, ethanol, and isopropanol are preferred. By using the alcohol solution, the time required to dissolve the component (b) in the component (a) can be shortened. In terms of operation, the higher the concentration of the boron compound in the alcohol, the better.

The reaction product of the components (a) and (b) in the above preferred embodiment is preferably a reaction product obtained by reacting the components (a) and (b) without adding water for hydrolysis. In this case, since the step of adding water for hydrolysis is not required, the complex steps of melt-gel formation and the like are not required, and the reaction product can be produced without a long time.

(c) Fluorine-Containing Compound The component (c) used in the present invention is a fluorine-containing compound represented by the following formula (II). In the above formula (II), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group, x is an integer of 1 to 100, and y is an integer of 0 to 100.

In the above formula (II), examples of the fluoroalkyl group represented by ^R1 include fluoroalkyl groups represented by -CqF2q ₊₁ ( _q =1 to ₁₀ ) such as _{-CF3 , -C2F5 , -C3F7} , _-C6F13 , _-C7F15 , etc.; oxyfluoroalkylene groups; and the like. Among these, the oxyfluoroalkylene group represented _by the following formula (III) is preferred. In the above formula (II), p is an integer from 0 to 2.

In the above formula (I), examples of the alkyl group represented by ^R2 include alkyl groups having 1 to 2 carbon atoms, such as methyl and ethyl groups, and examples of the alkoxyalkyl group represented by ^R2 include alkoxyalkyl groups having 2 to 4 carbon atoms, such as methoxymethyl, methoxyethyl, ethoxymethyl, and ethoxyethyl groups. Among these, the group represented by ^R2 is preferably an alkyl group, and particularly preferably a methyl group.

In the above formula (I), examples of the organic groups represented by R ³ and R ⁴ include groups represented by the following formulae (i) to (v).

In the above formula (I), the number x of intermediate chains (-CH2 _- CH-) bonded to trialkoxysilyl groups or trialkoxyalkoxysilyl groups (-Si( ^OR2 ) ₃ ) is 1-100, preferably 1-50, more preferably 1-10, and particularly preferably 2-5. The number y of intermediate chains ( _-CH2 ^{-CR3R4- )} is 0-100, preferably 0-50, and more preferably 0-10.

As compounds suitable for the above-mentioned fluorine-containing compound, compounds represented by the following formulas (IIa) to (IIe) can be exemplified. In particular, if the above-mentioned fluorine-containing compound is a compound represented by the following formula (IIa) or formula (IIb) (a compound in which y=0 in the above-mentioned formula (II)), the ratio of fluorine atoms in one molecule is large, and the modification reaction by the fluorine-containing compound (c) can be efficiently performed.

In formula (IIa), x' is 2 or 3.

In formula (IIb) and formula (IIc), R ^1' is a group represented by -CF(CF ₃ )OCF ₂ CF(CF ₃ )OC ₃ F _7. In formula (IIb), xa is an integer of 1 to 100. In formula (IIc), xb is an integer of 1 to 100, and yb is an integer of 1 to 500.

In formula (IId), xc is an integer from 1 to 10, and yc is an integer from 0 to 100.

In formula (IIe), xd is an integer from 1 to 10, and yd is an integer from 0 to 100.

The method for preparing the fluorine-containing compound represented by the above formula (II) is not particularly limited, but it is preferably obtained by polymerizing a monomer represented by the following formula (2b) and a monomer represented by the following formula (2c) in the presence of a fluorine-containing peroxide represented by the following formula (2a). In addition, in this reaction product (fluorine-containing compound), an oligomer in which a fluoroalkyl group (R ¹ ) is introduced only to one end may be included in any proportion. In formulae (2a) to (2c), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, and ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group.

The amount of the fluorine-containing compound (c) used is not particularly limited, and can be appropriately set in consideration of the purpose or required properties of the coating composition, and the reaction conditions or reactivity with the (a) amino-containing silane compound and/or (b) boron compound. It is preferably used in an amount of 0.002 to 0.5 mol, and particularly preferably 0.02 to 0.3 mol, relative to 1 mol of the total amount of the components (a) and (b). From the viewpoint of water repellency and oil repellency, the amount of the fluorine-containing compound (c) used is preferably 0.002 mol or more relative to 1 mol of the total amount of the components (a) and (b). From the viewpoint of coating film appearance, the amount of the fluorine-containing compound (c) used is 1 mol, preferably 0.5 mol or less, based on the total amount of the components (a) and (b).

(d) Organic solvent The coating composition of the present invention preferably contains (d) organic solvent from the viewpoint of reaction speed or uniformity, ease of coating operation, etc. The above-mentioned (d) organic solvent is not particularly limited, and an organic solvent that is liquid at room temperature and can dissolve or disperse the above-mentioned components, especially components (a) to (c), can be suitably used.

From the viewpoint of affinity with each of the above components having a part of polar groups or affinity with the coated object, the above organic solvent (d) is preferably a so-called water-soluble organic solvent having a certain polarity and being compatible with water. The water-soluble organic solvent preferably used as the component (d) is not particularly limited as long as it acts as a diluent and is water-soluble. For example, alcohols and esters can be preferably used. Among them, it is preferred to use an organic solvent containing an alcohol having 1 to 5 carbon atoms as the component (d). The alcohol having 1 to 5 carbon atoms may be linear or branched. If it is branched (in this case, the carbon number is 3 to 5), it is particularly preferred to achieve better water repellency and oil repellency. At this time, at least a portion of the alcohols having 1 to 5 carbon atoms are preferably branched alcohols having 3 to 5 carbon atoms, and particularly preferably all of them are branched alcohols having 3 to 5 carbon atoms. Also, higher molecular weight alcohols such as methoxymethylbutanol (MMB) can be used or used in combination. When such higher molecular weight alcohols or esters such as ethyl acetate are used, the same good water repellency and oil repellency can be achieved as when using straight chain alcohols having 1 to 5 carbon atoms.

Since an alcohol having a carbon number of 1 or more is used, the coating obtained from the coating composition of this embodiment can more effectively achieve excellent properties as a water-repellent and oil-repellent coating, such as a small water roll-off angle or excellent exotic ink resistance. Since an alcohol having a carbon number of 5 or less is used, the coating composition of this embodiment can achieve excellent coating properties.

There is no particular restriction on the amount of the organic solvent (d). It can be appropriately set while considering the reaction efficiency between the components headed by the above-mentioned components (a) to (c), the efficiency or workability of the coating operation, the quality of the resulting coating, etc. If the general use form of water-repellent and oil-repellent coating is taken as the premise, the amount of the organic solvent (d) used is preferably 20-90% by mass of the coating composition, and more preferably 40-70% by mass.

(e) Metal alkoxide The coating composition of the present invention may preferably further contain (e) metal alkoxide (except for (a) component or (c)). Therefore, the polymer substance that can be formed by the reaction of the coating composition of this embodiment is a polymer structure of the reaction product of the above-mentioned components (a) to (c), but may further have a structure modified by (e) metal alkoxide. That is, during the reaction of the above-mentioned components (a) and (b), or after the reaction, the metal alkoxide (component (e)) may be added. By adding (e) metal alkoxide, the polymer structure can be appropriately adjusted, or the content of the metal salt in the obtained reaction product can be increased, and the mechanical properties, chemical properties, etc. can be further improved. At the same time, it can become a viscous fluid state similar to the case where the (e) component is not used, so the properties and physical properties of the coating can be appropriately adjusted according to the application.

Among the metal alkoxides of the component (d), compounds corresponding to the above-mentioned component (a) (silane compounds containing amino groups having a specific structure) and compounds corresponding to the above-mentioned component (c) (fluorine-containing compounds having a specific structure) are excluded. However, the restrictions other than these do not apply to the metal alkoxides of the component (e). As long as they are not equivalent to the above-mentioned components (a) and (c), compounds generally classified as metal alkoxides, that is, compounds having at least one metal atom and at least one alkoxy group, can be used as the metal alkoxides of the component (e).

As the metal of the metal alkoxide as the component (e), Si, Ta, Nb, Ti, Zr, Al, Ge, B, Na, Ga, Ce, V, Ta, P, Sb, etc. can be cited, but it is not limited to these. From the perspective of the ease of forming the alkoxide, Si, Ti, and Zr are preferred. In addition, since the component (e) is preferably a liquid, Si and Ti are particularly preferred from the perspective of realizing it. As the alkoxide (alkoxy) of the metal alkoxide as the component (e), methoxy, ethoxy, propoxy, butoxy, and alkoxy groups having a carbon number greater than these can be cited. Methoxy, ethoxy, propoxy, and butoxy are preferred, and methoxy and ethoxy are more preferred. As particularly preferred components (e), tetramethoxysilane and tetraethoxysilane can be cited. The component (e) may be a polymer, for example, a pentamer of tetraethoxysilane is suitable. A monomer and a pentamer may also be used in combination.

The amount of component (e) used is not particularly limited and can be appropriately set according to the purpose of the obtained coating, the desired characteristics, etc., but for example, a ratio of 10 mol or less can be used relative to 1 mol of component (a). A ratio of 0.1 mol to 5 mol relative to 1 mol of component (a) is more preferred. Since component (d) is 0.1 mol or more relative to 1 mol of component (a), the effect of adding component (d) as described above can be fully demonstrated. In addition, since component (d) is set to 10 mol or less, the occurrence of white turbidity can be effectively suppressed.

(f) Surfactant In the coating composition of the present invention, (f) surfactant may be further added for the purpose of improving wettability with the substrate. The type of surfactant is not particularly limited and may be appropriately selected according to the coating operation form or affinity with other components, especially (d) organic solvent. The surfactant may be any of anionic surfactant, cationic surfactant, amphoteric surfactant and non-ionic surfactant.

There is no particular restriction on the amount of surfactant added, and it can be appropriately set according to the coating operation form or the physical properties required after curing. If the coating composition is used in a general form, the amount of surfactant (f) used is preferably 0.01-5.0% by mass of the coating composition, and is particularly preferably 0.1-1.0% by mass.

Synthetic resin The coating composition of the present invention may further contain a synthetic resin instead of or in addition to the aforementioned (e) metal alkoxide. That is, the synthetic resin may be added during or after the reaction of the aforementioned (a) component and (b) component. By adding the synthetic resin, the resulting coating layer may be provided with anti-cracking properties, and the coating composition of the present invention may be used, for example, as a resin hard coating agent.

The synthetic resins that can be used in the present invention are not particularly limited, and examples thereof include acrylic resins, epoxy resins, polyester resins, amino resins, urethane resins, and furan resins, and synthetic resins having various polymerization degrees (molecular weights) can be used. In addition, vinyl ester resins, epoxy acrylates, dipentaerythritol hexaacrylate, etc. can also be preferably used. Among them, from the perspective of the properties of the resin such as strength, the reactivity with other components, the stability, etc., it is preferred to use (g) epoxy resin.

(g) Epoxy resin The coating composition of the present invention may contain (g) epoxy resin in addition to the above-mentioned (a) to (c) components. (g) Epoxy resin can be incorporated into the polymer structure composed of the above-mentioned (a) components and (b) components during curing to form a part of the polymer structure. In addition, the polymer structure can be cross-linked to change the chemical structure or physical properties of the reaction product of the (a) components and (b) components. The coating composition of this embodiment, because it contains (g) epoxy resin, can affect the chemical structure or physical properties of the reaction product constituting the cured coating layer, and can suppress the reactivity or mechanical properties of the coating layer.

The (g) epoxy resin that can be preferably used in this embodiment is not particularly limited, as long as it is a resin classified as an epoxy resin in the industry, that is, a thermosetting resin that can form a cross-linked network with epoxy groups in the polymer structure and be cured, and epoxy resins with various polymerization degrees (molecular weights) can be used. Among them, it is preferable to use at least one epoxy resin selected from the group consisting of bisphenol A or bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins, epoxy resins of epoxy propyl esters, aliphatic epoxy resins, and polyethylene glycol epoxy resins.

There is no particular restriction on the amount of (g) epoxy resin added, and it can be appropriately set according to the coating operation form or the physical properties required after hardening. If the coating composition is used in a general form, the amount of (g) epoxy resin used is preferably 1 to 30 g, and more preferably 4 to 10 g, relative to 1 g of the aforementioned (a) component. That is, if the amount of (g) epoxy resin added is not too large, it tends to suppress the reduction in hardness, and conversely, if it is not too small, it tends to be easier to maintain chemical durability.

The coating layer and the method for producing the same can be produced by coating the coating composition of the present invention on a substrate and curing the coating composition. That is, the method for producing the coating layer of this embodiment comprises the steps of reacting the following components (a), (b) and (c): (a) a silane compound containing an amino group represented by the following formula (I): (wherein, R represents an organic group containing an amine group, R' represents a methyl group, an ethyl group or a propyl group, and n represents an integer selected from 1 to 3); (b) at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O ₃ ; (c) a fluorine-containing compound represented by the following formula (II); (In the above formula (II), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group, x is an integer of 1 to 100, and y is an integer of 0 to 100.) Here, the details of components (a) to (c) and their preferred embodiments are the same as those described above regarding the coating composition of the present invention.

The step of reacting the above-mentioned components (a), (b) and (c) is preferably carried out in an organic solvent (d), and the organic solvent (d) preferably contains 20% by mass or more of an alcohol having 1 to 5 carbon atoms. Here, the details of the organic solvent (d) and its preferred embodiment are the same as those described above regarding the coating composition of the present invention. That is, the above-mentioned step is preferably carried out in a composition containing 20% by mass or more of the organic solvent (d).

In the step of reacting the above-mentioned components (a), (b) and (c), (e) metal alkoxide (excluding components equivalent to (a) or (c), (g) synthetic resins such as epoxy resins, (f) surfactants, etc., may be further used in combination. Here, the details of (e) metal alkoxide, (g) synthetic resins such as epoxy resins and (f) surfactants and their preferred embodiments are the same as those described above regarding the coating composition of the present invention.

In the method for manufacturing the coating layer of this aspect, the coating composition of the present invention can be applied to the surface of the substrate by dipping, spray coating, roller coating, brush coating, etc. The coating layer can be formed by coating once, or by repeating the coating process more than twice. When the coating layer is formed by repeating the coating process more than twice, the coating composition can be cured after coating, and then further coating can be performed, or the coating can be repeated without curing, and the coating composition can be cured after all coating processes are completed. Heating during curing is not necessary, but heating can shorten the curing time.

The coating amount of the coating composition is not particularly limited, but is preferably 0.3 g to 10 g, particularly preferably 0.5 g to 2.0 g, and most preferably 1.0 g or more per 100 cm ² of the substrate area. Since the coating amount is 0.3 g or more per 100 cm ² of the substrate area, a coating layer of sufficient thickness can be formed.

The thickness of the coating layer after curing is not particularly limited and can be appropriately set according to the purpose of coating, required physical properties, usage of the coated component, etc., but is preferably 0.1 to 25 μm, particularly preferably 1 to 10 μm.

The substrate on which the coating layer is formed is particularly limited, and for example, at least one substrate (substrate) selected from the group consisting of paper, cloth, wood, plastic, other coating films, stone, ceramic, metal and metal alloy can be cited. Among them, by forming a coating layer of the coating composition of the present invention on a metal substrate, a glass substrate, a wood substrate or a ceramic substrate, high water repellency and oil repellency can be imparted to the substrate.

The coating composition of the present invention can greatly improve the water-repellency and oil-repellency of the coating layer after curing, maintain a good appearance, etc. On the other hand, according to needs or desires, a coating layer can be realized that can appropriately have high hardness, crack prevention, transparency, heat resistance, chemical resistance, etc. of a polymer substance derived from the reaction of an organic silane compound and a boron compound. Therefore, it is useful as a surface protective agent for home appliances, automobile parts, building structures, etc., and is particularly suitable for use in buildings, interior and exterior materials for construction, and interior and exterior materials for transportation machinery of automobiles, etc., which require high water-repellency and oil-repellency from the perspective of appearance protection or hygiene. [Example]

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

In the following Examples/Comparative Examples, the evaluation of physical properties/characteristics was performed by the following method. Preparation of coating film The coating composition obtained in each Example/Comparative Example was applied to a slide glass and aged for 168 hours at a temperature of 20°C and a humidity of 70±10%RH to obtain a coating film. The following items were evaluated for the obtained film. Coating state The appearance of the coating film was visually observed (whether there was whitening). Pencil hardness Evaluated according to the method of JIS K-5600-5-4 (load: 750±10g). Water contact angle The contact angle of water was measured using a contact angle meter (DropMaster 301, manufactured by Kyowa Interface Science Co., Ltd.) in accordance with JIS R 3257. Oil contact angle The contact angle of hexadecane was measured using a contact angle meter (DropMaster 301, manufactured by Kyowa Interface Science Co., Ltd.) in accordance with JIS R 3257. Water sliding angle The test piece (glass slide) with the coating film formed was placed on a horizontal surface, and 40 μL of ion-exchanged water was dropped onto the surface of the coating film to form water drops. From this state, the test piece was gradually tilted relative to the horizontal plane, and the angle at which the water droplet began to flow was measured and regarded as the water sliding angle. Magic ink resistance Draw a line on the surface of the coating with a black magic pen and test whether the line can be wiped off by wiping with toilet paper. Evaluate according to the following criteria. ○: The line is completely wiped off by wiping △: The line is partially wiped off by wiping ×: The line cannot be wiped off by wiping

(Example 1) 70 parts by mass of tetraethoxysilane pentamer (manufactured by COLCOAT Co., Ltd., product name: ethyl silicate 40), 70 parts by mass of tetraethoxysilane monomer (manufactured by COLCOAT Co., Ltd., product name: ethyl silicate 28), 40 parts by mass of γ-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE903), and 10 parts by mass of boric acid (H ₃ BO ₃ ) were weighed, mixed, and stirred for more than 1 hour. Then, 20 parts by mass of bisphenol A diglycidyl ether (manufactured by NAGASE CHEMTEX Co., Ltd., product name: EX-252) and 200 parts by mass of methanol as a diluent were added, and stirred for more than 30 minutes. To the entire coating stock solution obtained by the above operation, 5 parts by mass of a fluorine-containing compound represented by the following formula (IIa') was added, and the mixture was stirred for more than 3 hours to obtain the coating solution (coating composition) of Example 1. The obtained coating composition was used to prepare a coating film according to the above method, and the properties were evaluated. The results are shown in Table 1.

(Example 2) Except that an equal amount of ethanol was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition and the properties were evaluated. The results are shown in Table 1.

(Example 3) Except that an equal amount of n-propanol was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition and the properties were evaluated. The results are shown in Table 1.

(Example 4) Except that an equal amount of isopropyl alcohol was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition and the properties were evaluated. The results are shown in Table 1.

(Example 5) Except that an equal amount of n-butanol was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition and the properties were evaluated. The results are shown in Table 1.

(Example 6) Except that an equal amount of 2-butanol was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition and the properties were evaluated. The results are shown in Table 1.

(Example 7) Except that an equal amount of tertiary butyl alcohol was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition and the properties were evaluated. The results are shown in Table 1.

(Example 8) Except that an equal amount of n-hexanol was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition, and the properties were evaluated. The results are shown in Table 1.

(Example 9) Except that an equal amount of ethyl acetate was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition and the properties were evaluated. The results are shown in Table 1.

(Example 10) Except that an equal amount of methoxymethylbutanol (MMB) was used as a solvent instead of methanol, a coating composition was obtained in the same manner as in Example 1, and a coating film was prepared using the composition and the properties were evaluated. The results are shown in Table 1.

(Comparative Example) 70 parts by mass of tetraethoxysilane pentamer (manufactured by COLCOAT Co., Ltd., product name: Ethyl Silicate 40), 70 parts by mass of tetraethoxysilane monomer (manufactured by COLCOAT Co., Ltd., product name: Ethyl Silicate 28), 40 parts by mass of γ-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE903), and 10 parts by mass of boric acid (H ₃ BO ₃ ) were weighed, mixed, and stirred for more than 1 hour. Then, 20 parts by weight of bisphenol A diglycidyl ether (manufactured by Nagase Chemtex Co., Ltd., product name: EX-252), 1.2 parts by weight of VORASURF SZ-1919 (manufactured by DOW), and 200 parts by weight of methoxymethyl butanol (MMB) as a diluent were added, and stirred for more than 30 minutes. The coating liquid (coating composition) of the comparative example was obtained by stirring for more than 3 hours. The coating film was prepared using it, and the characteristics were evaluated. The results are shown in Table 1.

Each embodiment that satisfies the requirements specified in claim 1 of the present invention exhibits water-repellency and oil-repellency as expected in terms of water contact angle and oil contact angle, and the water sliding angle is 30° or less. Among them, the embodiment using an alcohol having 1 to 5 carbon atoms exhibits good results, and particularly good results are obtained in embodiments 4, 6, and 7 using a branched alcohol (in this case, having 3 to 5 carbon atoms). [Possibility of Industrial Application]

The coating composition of the present invention can achieve both water repellency and oil repellency of the coating obtained therefrom at a high level exceeding the limit of the conventional technology, and can preferably maintain the excellent properties of high hardness and transparency of the polymer obtained by reacting an organic silane compound with a boron compound. Therefore, it has a high possibility of application in various fields of industries such as construction, transportation machinery for automobiles, and electrical and electronic machinery.

Claims (8)

A coating composition comprises the following components (a), (b), (c), (d) and (g): (a) a silane compound R _4-n -Si-(OR') _n -(I) containing an amino group represented by the following formula (I) (wherein R represents an organic group containing an amino group, R' represents a methyl group, an ethyl group or a propyl group, and n represents an integer selected from 1 to 3); (b) at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O ₃ ; (c) a fluorine-containing compound represented by the following formula (II);

(In the above formula (II), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group, x is an integer from 1 to 100, and y is an integer from 0 to 100); (d) an organic solvent containing a branched alcohol having 3 to 5 carbon atoms; (g) an epoxy resin. The coating composition of claim 1 contains 20% by mass or more of the aforementioned (d) organic solvent. The coating composition of claim 1 or 2 further contains (e) metal alkoxide (excluding the equivalent of component (a) or component (c)). A method for producing a coating layer comprises the steps of reacting the following components (a), (b), (c), (d) and (g): (a) a silane compound R _4-n -Si-(OR') _n -(I) containing an amino group represented by the following formula (I) (wherein R represents an organic group containing an amino group, R' represents a methyl group, an ethyl group or a propyl group, and n represents an integer selected from 1 to 3); (b) at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O ₃ ; (c) a fluorine-containing compound represented by the following formula (II);

(In the above formula (II), ^R1 represents a group containing a fluoroalkyl group, ^R2 represents an alkyl group or an alkoxyalkyl group, ^R3 and ^R4 each independently represent a hydrogen atom or a monovalent organic group, x is an integer from 1 to 100, and y is an integer from 0 to 100); (d) an organic solvent containing a branched alcohol having 3 to 5 carbon atoms; (g) an epoxy resin. A method for manufacturing a coating layer as claimed in claim 4, wherein the aforementioned steps are carried out in a composition containing 20% by mass or more of (d) an organic solvent. The method for producing a coating layer as claimed in claim 4, wherein in the aforementioned steps, the components (a), (b) and (c) are further reacted with (e) a metal alkoxide (except for components (a) or (c)). A method for manufacturing a coating layer, comprising the step of coating a coating composition as described in any one of claims 1 to 3. The method for manufacturing a coating layer as claimed in claim 4 or 7 is to form a coating layer on a metal substrate, a glass substrate, a wood substrate or a ceramic substrate.