JPWO2018143361A1 - Water repellent powder - Google Patents

Abstract

In the infrared absorption spectrum measured using Fourier transform infrared spectroscopy, the present invention defines a peak intensity at a wave number of 1070 cm-1 derived from a network structure of Si-O-Si bonds as 1.0. The present invention relates to a water-repellent powder having a peak intensity near a wave number of 1270 cm −1 derived from a Si—CH 3 structure of 0.2 to 0.7.

Description

  The present disclosure relates to a water repellent powder.

  Conventionally, imparting water repellency to transparent substrates such as glass and plastics products is required for many products for the purpose of minimizing adhesion of water droplets and ensuring visibility. Usually, the water-repellent performance is obtained by forming a film (hereinafter referred to as “water-repellent film”) with a coating material having excellent water repellency on the surface of the substrate. The water repellent film generally refers to a film having a water contact angle of 90 ° or more.

  As a material for forming the water repellent film, polytetrafluoroethylene (PTFE) and its derivatives are known. However, since the temperature for hardening PTFE is several hundred degrees or more, the location and base material to which it is applied are limited.

  Patent Documents 1 and 2 describe forming a water repellent film using fluoroalkylsilane.

JP 2002-105661 A JP 2000-81214 A

  Since the water-repellent film formed from fluoroalkylsilane does not have sufficient adhesion to the substrate, it is difficult to form a water-repellent film excellent in flexibility by applying fluoroalkylsilane to the substrate. Therefore, there is a demand for a water-repellent material that is excellent in flexibility while maintaining water repellency.

  This invention is made | formed in view of said situation, and it aims at providing the water-repellent powder excellent in water repellency and a softness | flexibility.

  As a result of intensive studies to achieve the above object, the present inventor has found that water-repellent powder having a specific silicon bond unit exhibits excellent water repellency and flexibility. It was completed.

In one embodiment of the present invention, in an infrared absorption spectrum measured using Fourier transform infrared spectroscopy, the peak intensity at a wave number of 1070 cm ⁻¹ derived from a network structure of Si—O—Si bonds is defined as 1.0. The water-repellent powder having a peak intensity near the wave number of 1270 cm ⁻¹ derived from the Si—CH ₃ structure is 0.2 to 0.7.

In another aspect, the present invention is derived from Q and T when the silicon-containing bonding units Q, T, and D are defined as follows in a solid ²⁹ Si-NMR spectrum measured using the DD / MAS method. The ratio Q + T: D of the signal area derived from D and the signal area derived from D is 1: 0.01 to 1: 0.5. However, in the following, the organic group is a monovalent organic group in which an atom bonded to a silicon atom is a carbon atom.
Q: A silicon-containing bond unit having four oxygen atoms bonded to one silicon atom.
T: A silicon-containing bond unit having three oxygen atoms bonded to one silicon atom and one hydrogen atom or monovalent organic group.
D: A silicon-containing bond unit having two oxygen atoms bonded to one silicon atom and two hydrogen atoms or two monovalent organic groups.

In another aspect, the present invention provides a water-repellent powder having a structure represented by the following general formula (1).
[In Formula (1), R ¹ and R ² each independently represent an alkyl group or an aryl group, and R ³ and R ⁴ each independently represent an alkylene group. ]

In another aspect, the present invention provides a water-repellent powder having a ladder structure including a support portion and a bridge portion, and the bridge portion is represented by the following general formula (2).
[In Formula (2), R ⁵ and R ⁶ each independently represents an alkyl group or an aryl group, and b represents an integer of 1 to 50. ]

From the viewpoint of further improving water repellency and flexibility, the water-repellent powder may have a ladder structure represented by the following general formula (3).
[In Formula (3), R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group, a and c each independently represent an integer of 1 to 3000, and b represents 1 to 50 Indicates an integer. ]

  From the viewpoint of improving the formability and adhesion of the water-repellent film to the surface to be processed of the object, the average particle diameter D50 of the water-repellent powder may be 1-1000 μm.

  According to the present invention, a water-repellent powder excellent in water repellency and flexibility can be provided. Since the water-repellent powder of the present invention can impart water repellency to the surface to be treated at a low temperature, it can impart excellent water repellency even to an object having no heat resistance. Moreover, since this water-repellent powder is excellent in flexibility, it is excellent in adhesion to an object and can maintain a water-repellent function for a long period of time.

Is a diagram showing an example of a solid-state ^{29 Si-NMR} spectrum of the water-repellent powder of the present embodiment. It is a figure which shows the calculation method of the biaxial average primary particle diameter of particle | grains. It is a figure which shows the infrared absorption spectrum of the water repellent powder produced in the Example and the comparative example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. However, the present invention is not limited to the following embodiments.

<Definition>
In this specification, the numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value of a numerical range in a certain step may be replaced with the upper limit value or the lower limit value of a numerical range in another step. In the numerical range described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples. “A or B” only needs to include either A or B, and may include both. The materials exemplified in the present specification can be used singly or in combination of two or more unless otherwise specified. In the present specification, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. means.

<Specific embodiment of water repellent powder>
Examples of the water-repellent powder of the present embodiment include the following first to fifth aspects. By adopting the first to fifth aspects, it becomes easy to achieve both water repellency and flexibility of the water repellent powder. Moreover, the water-repellent powder which has water repellency and a softness | flexibility according to each aspect can be obtained by employ | adopting each aspect. In the present embodiment, the water-repellent powder refers to “a granular material having a porous structure”.

(First aspect)
The water-repellent powder of this embodiment has a peak intensity at a wave number of 1070 cm ⁻¹ derived from the network structure of Si—O—Si bond in the infrared absorption spectrum measured using Fourier transform infrared spectroscopy as 1.0. A water-repellent powder having a peak intensity in the vicinity of a wave number of 1270 cm ⁻¹ (for example, a range of wave numbers of 1280 to 1260 cm ⁻¹ ) derived from the Si—CH ₃ structure when defined. Also good. The peak intensity near the wave number of 1270 cm ⁻¹ may further be 0.2 to 0.6, or may be 0.2 to 0.5. When the peak intensity is 0.2 or more, excellent water repellency derived from the Si-CH ₃ structure can be imparted, and when the peak intensity is 0.7 or less, excellent water repellency derived from the siloxane skeleton. Flexibility can be obtained.

  The infrared absorption spectrum of the water-repellent powder can be measured by a Fourier transform infrared spectrometer. In particular, the total reflection measurement method (ATR method) using diamond as a high refractive index medium (prism) that is transparent in the infrared region. ) Can be measured with higher accuracy. Although it does not specifically limit to the kind of infrared spectrometer to be used, For example, FT-IR / 6300 (made by JASCO Corporation), ALPHA compact FT-IR (made by Bruker Optics Corporation), etc. can be used.

(Second embodiment)
The water repellent powder of this embodiment can contain polysiloxane having a main chain containing a siloxane bond (Si—O—Si). The water repellent powder may have the following M unit, D unit, T unit or Q unit as a structural unit.

  In the above formula, R represents a monovalent organic group. The M unit is a unit composed of a monovalent group in which a silicon atom is bonded to one oxygen atom. The D unit is a unit composed of a divalent group in which a silicon atom is bonded to two oxygen atoms. The T unit is a unit composed of a trivalent group in which a silicon atom is bonded to three oxygen atoms. The Q unit is a unit composed of a tetravalent group in which a silicon atom is bonded to four oxygen atoms. Information on the content of these units can be obtained by Si-NMR.

The water-repellent powder of this embodiment is derived from Q and T when the silicon-containing bond units Q, T, and D are defined as follows in the solid ²⁹ Si-NMR spectrum measured using the DD / MAS method. The water repellent powder may have a ratio Q + T: D between the signal area and the signal area derived from D of 1: 0.01 to 1: 0.50.
Q: A silicon-containing bond unit having four oxygen atoms bonded to one silicon atom.
T: A silicon-containing bond unit having three oxygen atoms bonded to one silicon atom and one hydrogen atom or monovalent organic group.
D: A silicon-containing bond unit having two oxygen atoms bonded to one silicon atom and two hydrogen atoms or two monovalent organic groups.

  The ratio Q + T: D of the signal area derived from Q and T and the signal area derived from D may be 1: 0.01 to 1: 0.45, and may be 1: 0.02 to 1: 0. It may be 40. When the signal area ratio is 1: 0.01 or more, there is a tendency that it is easy to obtain superior water repellency, and when it is 1: 0.50 or less, there is a tendency that flexibility is easily obtained. When the signal area ratio Q + T: D is included in this range, water repellency and flexibility can be further improved.

  The “oxygen atom” in Q, T, and D is an oxygen atom that mainly bonds between two silicon atoms. For example, it may be an oxygen atom having a hydroxyl group bonded to a silicon atom. The “organic group” is a monovalent organic group in which the atom bonded to the silicon atom is a carbon atom, and examples thereof include an unsubstituted or substituted monovalent organic group having 1 to 10 carbon atoms. Examples of the unsubstituted monovalent organic group include hydrocarbon groups such as an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group, and an aralkyl group. The substituted monovalent organic groups include hydrocarbon groups (substituted organic groups) in which hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms, predetermined functional groups, predetermined functional group-containing organic groups, and the like. A hydrocarbon group in which a hydrogen atom of a ring such as a cycloalkyl group, an aryl group or an aralkyl group is substituted with an alkyl group can be mentioned. Examples of the halogen atom include a chlorine atom and a fluorine atom (that is, a halogen atom-substituted organic group such as a chloroalkyl group or a polyfluoroalkyl group). Examples of the functional group include a hydroxyl group, a mercapto group, and a carboxyl group. Examples of functional group-containing organic groups include groups, epoxy groups, amino groups, cyano groups, acryloyloxy groups, and methacryloyloxy groups, such as alkoxy groups, acyl groups, acyloxy groups, alkoxycarbonyl groups, glycidyl groups, and epoxycyclohexyl groups. Groups, alkylamino groups, dialkylamino groups, arylamino groups and N-aminoalkyl-substituted aminoalkyl groups.

The signal area ratio can be confirmed by a solid ²⁹ Si-NMR spectrum. Generally, the measurement method of solid ²⁹ Si-NMR is not particularly limited, and examples thereof include CP / MAS method and DD / MAS method. In this embodiment, DD / MAS method is adopted from the viewpoint of quantitativeness. ing.

The chemical shifts of silicon-containing bond units Q, T, and D in the solid ²⁹ Si-NMR spectrum are in the ranges of Q units: -90 to -120 ppm, T units: -45 to -80 ppm, D units: 0 to -40 ppm, respectively. As observed, it is possible to separate the signals of silicon-containing binding units Q, T and D and calculate the signal area derived from each unit. In the spectrum analysis, an exponential function is adopted as the window function from the viewpoint of improving the analysis accuracy, and the line broadcasting coefficient can be set in the range of 0 to 50 Hz.

FIG. 1 is a diagram showing an example of a solid ²⁹ Si-NMR spectrum of the water-repellent powder of this embodiment, measured using the DD / MAS method. As shown in FIG. 1, the signals of the silicon-containing binding units Q, T, and D can be separated by solid-state ²⁹ Si-NMR using the DD / MAS method.

  Here, a signal area ratio calculation method will be described with reference to FIG. For example, in FIG. 1, a Q unit signal derived from silica is observed in a chemical shift range of −90 to −120 ppm. Further, in the chemical shift range of −45 to −80 ppm, a signal of T unit derived from the polysiloxane compound and the trimethoxysilane reactant is observed. Further, in the chemical shift range of 0 to −40 ppm, a signal of D unit derived from the polysiloxane compound and the dimethyldimethoxysilane reactant is observed. The signal area (integrated value) is obtained by integrating the signal in each chemical shift range. When the signal area of the sum of Q units and T units is 1, the signal area ratio Q + T: D in FIG. 1 is calculated as 1: 0.13. The signal area can be calculated using general spectrum analysis software (for example, NMR software “TopSpin” manufactured by Bruker (TopSpin is a registered trademark)).

(Third embodiment)
The water repellent powder of this embodiment can have a structure represented by the following general formula (1).

The water repellent powder of this embodiment may have a structure represented by the following general formula (1a) as a structure including the structure represented by the formula (1).

In formula (1) and formula (1a), R ¹ and R ² each independently represent an alkyl group or an aryl group, and R ³ and R ⁴ each independently represent an alkylene group. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In formula (1a), p represents an integer of 1 to 50. In formula (1a), two or more R ^{1 s} may be the same or different, and similarly, two or more R ^{2 s} may be the same or different. In formula (1a), two R ^{3 s} may be the same or different, and similarly, two R ^{4 s} may be the same or different.

From the viewpoint of further improving the water repellency and flexibility of the water-repellent powder, in formula (1) and formula (1a), R ¹ and R ² are each independently an alkyl group having 1 to 6 carbon atoms or a phenyl group. There may be. The alkyl group may be a methyl group. In formula (1) and formula (1a), R ³ and R ⁴ may each independently be an alkylene group having 1 to 6 carbon atoms. The alkylene group may be an ethylene group or a propylene group. In formula (1a), p can be set to 2 to 30, and may be 5 to 20.

(Fourth aspect)
The water-repellent powder of the present embodiment is a water-repellent powder having a ladder type structure including a support portion and a bridge portion, and the bridge portion has a structure represented by the following general formula (2). It may be. By introducing such a ladder structure into the skeleton of the water-repellent powder, water repellency and flexibility can be improved. In this embodiment, the “ladder structure” has two struts and bridges connecting the struts (having a so-called “ladder” form). It is. In this embodiment, the skeleton forming the water repellent powder may have a ladder structure, but the water repellent powder may partially have a ladder structure.

In formula (2), R ⁵ and R ⁶ each independently represent an alkyl group or an aryl group, and b represents an integer of 1 to 50. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In formula (2), when b is an integer of 2 or more, two or more R ^{5 s} may be the same or different, and similarly two or more R ^{6 s} are each the same. May be different.

In addition, the conventional ladder type silsesquioxane has a structure represented by the following general formula (X), and the structure of the bridge portion is —O—. On the other hand, in the water-repellent powder of this embodiment, the structure of the bridging portion is a structure (polysiloxane structure) represented by the general formula (2).

  In formula (X), R represents a hydroxy group, an alkyl group or an aryl group.

There are no particular limitations on the structure serving as the support column and its chain length, and the interval between the structures serving as the bridging portions, but from the viewpoint of further improving the water repellency and flexibility, the ladder structure may be represented by the following general formula (3 ) Is a ladder structure.

In formula (3), R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent an alkyl group or an aryl group, a and c each independently represent an integer of 1 to 3000, and b is 1 to 50 Indicates an integer. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In Formula (3), when b is an integer of 2 or more, two or more R ^{5 s} may be the same or different, and similarly, two or more R ^{6 s} may be the same. May be different. In formula (3), when a is an integer of 2 or more, two or more R ^{7 s} may be the same or different. Similarly, when c is an integer of 2 or more, 2 or more R ⁸ may be the same or different from each other.

From the viewpoint of obtaining better flexibility, in formula (2) and formula (3), R ⁵ , R ⁶ , R ⁷ and R ⁸ (however, R ⁷ and R ⁸ are only in formula (3)) are: It may be independently an alkyl group having 1 to 6 carbon atoms or a phenyl group. The alkyl group may be a methyl group. In formula (3), a and c can be independently 6 to 2000, and may be 10 to 1000. In Formula (2) and Formula (3), b can be set to 2 to 30, and may be 5 to 20.

(Fifth aspect)
The water-repellent powder of the present embodiment includes a polysiloxane compound having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product (hydrolyzable product) of the polysiloxane compound having a hydrolyzable functional group. It is obtained by drying a wet gel produced from a sol containing at least one compound selected from the group consisting of hydrolyzed functional polysiloxane compounds (hereinafter sometimes referred to as “polysiloxane compound group”). It may be a thing. That is, the water-repellent powder of this embodiment is a group consisting of a hydrolyzable functional group or a polysiloxane compound having a condensable functional group, and a hydrolysis product of a polysiloxane compound having a hydrolyzable functional group. It may be a dried product of a wet gel which is a condensate of a sol containing at least one compound selected from the above. In addition, the water-repellent powder described so far also includes hydrolysis of a polysiloxane compound having a hydrolyzable functional group or a condensable functional group, and a polysiloxane compound having a hydrolyzable functional group. It may be obtained by drying a wet gel produced from a sol containing at least one selected from the group consisting of products.

  The hydrolyzable functional group and the condensable functional group in the polysiloxane compound are not particularly limited. Examples of the hydrolyzable functional group include an alkoxy group. Examples of condensable functional groups (excluding functional groups corresponding to hydrolyzable functional groups) include hydroxyl groups, silanol groups, carboxyl groups, phenolic hydroxyl groups, and the like. The hydroxyl group may be contained in a hydroxyl group-containing group such as a hydroxyalkyl group. A polysiloxane compound having a hydrolyzable functional group or a condensable functional group is a reactive group (hydrolyzable functional group and condensable functional group) different from the hydrolyzable functional group and the condensable functional group. You may further have a functional group which does not correspond to a functional group. Examples of the reactive group include an epoxy group, a mercapto group, a glycidoxy group, a vinyl group, an acryloyl group, a methacryloyl group, and an amino group. The epoxy group may be contained in an epoxy group-containing group such as a glycidoxy group. These polysiloxane compounds having functional groups and reactive groups may be used alone or in admixture of two or more. Of these functional groups and reactive groups, alkoxy groups, silanol groups, and hydroxyalkyl groups can further improve the compatibility of the sol. In addition, from the viewpoint of improving the reactivity of the polysiloxane compound and the wear resistance of the water repellent powder, the carbon number of the alkoxy group and the hydroxyalkyl group can be 1 to 6, but the wear resistance of the water repellent powder. It is good also as 2-4 from a viewpoint of improving more.

  Examples of the polysiloxane compound having a hydroxyalkyl group include compounds having a structure represented by the following general formula (A). By using a polysiloxane compound having a structure represented by the following general formula (A), the structure represented by the general formulas (1) and (1a) can be introduced into the skeleton of the water-repellent powder. .

In formula (A), R ^1a represents a hydroxyalkyl group, R ^2a represents an alkylene group, R ^3a and R ^4a each independently represents an alkyl group or an aryl group, and n represents an integer of 1 to 50. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In formula (A), two R ^{1a s} may be the same or different, and similarly, two R ^{2a s} may be the same or different. In formula (A), two or more R ^{3a s} may be the same or different, and similarly, two or more R ^{4a s} may be the same or different.

By using a wet gel (wet gel generated from the sol) which is a condensate of a sol containing the polysiloxane compound having the above structure, it becomes easier to obtain a water-repellent powder having excellent flexibility. From the same viewpoint, the following features may be satisfied. In the formula (A), examples of R ^1a include a hydroxyalkyl group having 1 to 6 carbon atoms, and specifically include a hydroxyethyl group and a hydroxypropyl group. In formula (A), examples of R ^2a include an alkylene group having 1 to 6 carbon atoms, and specific examples include an ethylene group and a propylene group. In formula (A), R ^3a and R ^4a may each independently be an alkyl group having 1 to 6 carbon atoms or a phenyl group. The alkyl group may be a methyl group. In formula (A), n can be set to 2 to 30, and may be 5 to 20.

  As the polysiloxane compound having the structure represented by the general formula (A), commercially available products can be used. For example, compounds such as X-22-160AS, KF-6001, KF-6002, KF-6003 and the like ( In any case, Shin-Etsu Chemical Co., Ltd.) and compounds such as XF42-B0970 and Fluid OFOH 702-4% (all manufactured by Momentive Co., Ltd.) can be mentioned.

  Examples of the polysiloxane compound having an alkoxy group include compounds having a structure represented by the following general formula (B). By using a polysiloxane compound having a structure represented by the following general formula (B), a ladder type structure including a bridge portion having a structure represented by the above general formula (2) is formed in the skeleton of the water-repellent powder. Can be introduced.

In formula (B), R ^1b represents an alkyl group, an alkoxy group or an aryl group, R ^2b and R ^3b each independently represent an alkoxy group, and R ^4b and R ^5b each independently represent an alkyl group or an aryl group. , M represents an integer of 1-50. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In the formula (B), two R ^{1b s} may be the same or different, and two R ^{2b s} may be the same or different. Similarly, R ^3b may be the same or different. In the formula (B), when m is an integer of 2 or more, two or more R ^4b may be the same or different, and similarly, two or more R ^5b may be the same. May be different.

By using a wet gel that is a condensate of a sol containing the polysiloxane compound having the structure described above or a hydrolysis product thereof, it becomes easier to obtain a water-repellent powder having excellent flexibility. From the same viewpoint, the following features may be satisfied. In formula (B), R ^1b includes, for example, an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms. Specifically, a methyl group, a methoxy group, and an ethoxy group include Can be mentioned. In formula (B), R ^2b and R ^3b may each independently be an alkoxy group having 1 to 6 carbon atoms. Examples of the alkoxy group include a methoxy group and an ethoxy group. In formula (B), R ^4b and R ^5b may each independently be an alkyl group having 1 to 6 carbon atoms or a phenyl group. The alkyl group may be a methyl group. In the formula (B), m can be 2 to 30, and may be 5 to 20.

  The polysiloxane compound having the structure represented by the general formula (B) can be obtained by appropriately referring to the production methods reported in, for example, JP-A Nos. 2000-26609 and 2012-233110. Can do.

  In addition, since the alkoxy group is hydrolyzed, the polysiloxane compound having an alkoxy group may exist as a hydrolysis product in the sol. The polysiloxane compound having an alkoxy group and the hydrolysis product are It may be mixed. In the polysiloxane compound having an alkoxy group, all of the alkoxy groups in the molecule may be hydrolyzed or partially hydrolyzed.

  Each of the polysiloxane compound having a hydrolyzable functional group or a condensable functional group and the hydrolysis product of the polysiloxane compound having a hydrolyzable functional group may be used alone or in combination of two or more. It may be used.

  In producing the water-repellent powder of the present embodiment, the sol containing the polysiloxane compound or the hydrolysis product thereof may contain a silicon compound other than the polysiloxane compound (excluding the polysiloxane compound). That is, the sol according to the present embodiment is selected from the group consisting of a silane monomer having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of the silane monomer having a hydrolyzable functional group. May be further contained (hereinafter, sometimes referred to as “silane monomer group”). The number of silicon atoms in the silane monomer can be 1-6.

  Although it does not specifically limit as a silane monomer which has a hydrolyzable functional group, For example, an alkyl silicon alkoxide is mentioned. Among alkyl silicon alkoxides, those having 3 or less hydrolyzable functional groups can further improve water resistance. Examples of the alkyl silicon alkoxide include monoalkyltrialkoxysilane, monoalkyldialkoxysilane, dialkyldialkoxysilane, monoalkylmonoalkoxysilane, dialkylmonoalkoxysilane and trialkylmonoalkoxysilane. Examples of the alkyl silicon alkoxide include methyltrimethoxysilane, methyldimethoxysilane, dimethyldimethoxysilane, and ethyltrimethoxysilane.

  The silane monomer having a condensable functional group is not particularly limited. For example, silane tetraol, methyl silane triol, dimethyl silane diol, phenyl silane triol, phenyl methyl silane diol, diphenyl silane diol, n-propyl silane triol, Examples include hexyl silane triol, octyl silane triol, decyl silane triol, and trifluoropropyl silane triol.

  The silane monomer having a hydrolyzable functional group or a condensable functional group may further have the aforementioned reactive group different from the hydrolyzable functional group and the condensable functional group. The number of hydrolyzable functional groups is 3 or less, and silane monomers having reactive groups include vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3 -Methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, N-phenyl-3-aminopropyl Trimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, and the like can also be used.

  As a silane monomer having a condensable functional group and having the above-mentioned reactive group, vinyl silane triol, 3-glycidoxypropyl silane triol, 3-glycidoxy propyl methyl silane diol, 3-methacryloxy propyl silane triol, 3-methacryloxypropylmethylsilanediol, 3-acryloxypropylsilanetriol, 3-mercaptopropylsilanetriol, 3-mercaptopropylmethylsilanediol, N-phenyl-3-aminopropylsilanetriol, N-2- (aminoethyl) ) -3-Aminopropylmethylsilanediol and the like can also be used.

  Bistrimethoxysilylmethane, bistrimethoxysilylethane, bistrimethoxysilylhexane, or the like can also be used as the silane monomer having 3 or less hydrolyzable functional groups at the molecular terminals.

  Each of the silane monomer having a hydrolyzable functional group or a condensable functional group and the hydrolysis product of the silane monomer having a hydrolyzable functional group may be used alone or in combination of two or more. Also good.

  The content of the polysiloxane compound group contained in the sol (content of the polysiloxane compound having a hydrolyzable functional group or condensable functional group, and the content of the polysiloxane compound having a hydrolyzable functional group) The total content of the hydrolysis products) can be 5 parts by mass or more with respect to 100 parts by mass of the sol, and may be 10 parts by mass or more. The content can be 50 parts by mass or less, or 30 parts by mass or less with respect to 100 parts by mass of the total amount of sol. That is, the content of the polysiloxane compound group can be 5 to 50 parts by mass with respect to 100 parts by mass of the total amount of sol, but may be 10 to 30 parts by mass. When the content is 5 parts by mass or more, good reactivity is further obtained and cheaper, and when it is 50 parts by mass or less, good compatibility is further easily obtained.

  When the sol further contains a silane monomer group, the content of the polysiloxane compound group and the content of the silane monomer group (content of the silane monomer having a hydrolyzable functional group or a condensable functional group, and , The total content of hydrolysis products of silane monomers having hydrolyzable functional groups) can be 1: 0.5 to 1: 4, but is also 1: 1 to 1: It may be 2. When the ratio of the content of these compounds is 1: 0.5 or more, good compatibility is further easily obtained, and when the ratio is 1: 4 or less, gel shrinkage is further easily suppressed.

  The sum total of content of a polysiloxane compound group and a silane monomer group can be 5 mass parts or more with respect to 100 mass parts of total amounts of sol, and may be 10 mass parts or more. The total content can be 50 parts by mass or less, or 30 parts by mass or less, with respect to 100 parts by mass of the total amount of sol. That is, the total content of the polysiloxane compound group and the silane monomer group can be 5 to 50 parts by mass with respect to 100 parts by mass of the sol, but may be 10 to 30 parts by mass. By making the sum of the contents 5 parts by mass or more, it becomes easier to obtain good reactivity, and by making it 50 parts by mass or less, it becomes easier to obtain good compatibility. At this time, the ratio of the content of the polysiloxane compound group and the silane monomer group can be within the above range.

  The sol according to this embodiment may further contain silica particles. That is, the water repellent powder of this embodiment may further have a structure based on silica particles. The silica particles can be used without particular limitation, and examples thereof include amorphous silica particles. Examples of the amorphous silica particles include fused silica particles, fumed silica particles, and colloidal silica particles. Among these, colloidal silica particles have high monodispersibility, and can easily suppress aggregation in the wet gel production process of the water-repellent powder. The silica particles may be silica particles having a hollow structure or a porous structure.

  The shape of the silica particles is not particularly limited, and examples thereof include a spherical shape, a cage shape, and an association type. Among these, by using spherical particles as the silica particles, it becomes easy to suppress aggregation in the wet gel generating step of the water-repellent powder. The average primary particle diameter of the silica particles may be, for example, 1 nm or more, or 5 nm or more, from the viewpoint that it becomes easy to obtain a water-repellent powder having an appropriate hardness and the durability against thermal shock and scratches is easily improved. It may be 20 nm or more. The average primary particle diameter of the silica particles may be, for example, 200 nm or less, 150 nm or less, or 100 nm or less from the viewpoint of easily obtaining a transparent water-repellent powder. From these viewpoints, the average primary particle diameter of the silica particles may be 1 to 200 nm, 5 to 150 nm, or 20 to 100 nm.

  In addition, about a silica particle, it is possible to measure an average particle diameter from a raw material. For example, the biaxial average primary particle diameter is calculated as follows from the result of observing 20 arbitrary particles by SEM. That is, when colloidal silica particles having a solid content concentration of 5 to 40% by mass, which are usually dispersed in water, are taken as an example, a chip with a 2 cm square wafer with a patterned wiring is immersed in the dispersion of colloidal silica particles for about 30 seconds. After that, the chip is rinsed with pure water for about 30 seconds and blown dry with nitrogen. Thereafter, the chip is placed on a sample stage for SEM observation, an acceleration voltage of 10 kV is applied, the silica particles are observed at a magnification of 100,000, and an image is taken. 20 silica particles are arbitrarily selected from the obtained image, and the average of the particle diameters of these particles is defined as the average particle diameter. At this time, when the selected silica particles have a shape as shown in FIG. 2, a rectangle (circumscribed rectangle L) circumscribing the silica particles P and arranged so that the long side is the longest is led. And the long side of the circumscribed rectangle L is X, the short side is Y, and the biaxial average primary particle diameter is calculated as (X + Y) / 2, and is defined as the particle diameter of the particle.

The number of silanol groups per gram of silica particles is, for example, not less than 10 × 10 ¹⁸ / g from the viewpoint of having good reactivity and easily imparting excellent water repellency and flexibility at a low temperature in a short time. It may be 50 × 10 ¹⁸ pieces / g or more, or 100 × 10 ¹⁸ pieces / g or more. The number of silanol groups per gram of the silica particles is, for example, 1000 × 10 ¹⁸ atoms / g or less from the viewpoint of easily suppressing rapid gelation in the wet gel production step of the water repellent powder and easily obtaining a uniform water repellent powder. It may be 800 × 10 ¹⁸ pieces / g or less, or 700 × 10 ¹⁸ pieces / g or less. From these viewpoints, the number of silanol groups per gram of silica particles may be, for example, 10 × 10 ^{18 to} 1000 × 10 ¹⁸ pcs / g, or 50 × 10 ^{18 to} 800 × 10 ¹⁸ pcs / g, at best, it may be a 100 × ^{10 18} ~700 × ¹⁰ 18 cells / g.

  The content of the silica particles contained in the sol according to the present embodiment is, for example, about 0.1% with respect to 100 parts by mass of the total amount of the sol from the viewpoint of improving the reactivity of the wet gel in the wet gel generation process of the water-repellent powder. It may be 01 parts by mass or more, 0.1 parts by mass or more, or 0.5 parts by mass or more. The content of the silica particles is, for example, 30 parts by mass or less with respect to 100 parts by mass of the total amount of sol, from the viewpoint of easily obtaining water-repellent powder having an appropriate hardness and easily improving durability against thermal shock and scratches. It may be 20 parts by mass or less, or 10 parts by mass or less. From these viewpoints, the content of the silica particles can be 0.01 to 30 parts by mass with respect to 100 parts by mass of the total sol, but may be 0.1 to 20 parts by mass. 5-10 mass parts may be sufficient.

<Method for producing water repellent powder>
Next, the manufacturing method of water repellent powder is demonstrated. Although the manufacturing method of water repellent powder is not specifically limited, For example, it can manufacture with the following method.

  That is, the water-repellent powder of the present embodiment was obtained in the sol generation step, the wet gel generation step in which the sol obtained in the sol generation step was gelled and then aged to obtain a wet gel, and the wet gel generation step. Manufacturing mainly comprising a wet gel pulverization step for pulverizing the wet gel, a step of washing and solvent substitution of the wet gel particles obtained in the wet gel pulverization step, and a drying step of drying the wet gel particles after washing and solvent substitution It can be manufactured by a method. The sol is a state before the gelation reaction occurs, and in this embodiment, the sol means a state in which the polysiloxane compound group and, in some cases, the silane monomer group are dissolved or dispersed in a solvent. . The wet gel means a gel solid in a wet state that contains a liquid medium but does not have fluidity.

  Hereinafter, each process of the manufacturing method of the water repellent powder of this embodiment is demonstrated.

(Sol generation process)
The sol production step is a step of producing a sol by mixing the above-described polysiloxane compound, if necessary, a silane monomer, silica particles, and a solvent and hydrolyzing them. In this step, an acid catalyst can be further added to the solvent to promote the hydrolysis reaction. Further, as disclosed in Japanese Patent No. 5250900, a surfactant, a thermohydrolyzable compound, or the like can be added to the solvent.

  As the solvent, for example, water or a mixed solution of water and alcohols can be used. Examples of alcohols include methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol and t-butanol. Among these, methanol, ethanol, 2-propanol etc. are mentioned as alcohol with a low surface tension and a low boiling point which is easy to reduce the interfacial tension with a gel wall. You may use these individually or in mixture of 2 or more types.

  For example, when alcohols are used as the solvent, the amount of alcohols can be 4 to 8 moles relative to 1 mole of the total amount of the polysiloxane compound group and the silane monomer group, but is further 4 to 6.5 moles. It is good also as 4.5-6 mol. By making the amount of alcohols 4 mol or more, it becomes easier to obtain good compatibility, and by making the amount 8 mol or less, it becomes easier to suppress gel shrinkage.

  Examples of the acid catalyst include inorganic acids such as hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, hypophosphorous acid, bromic acid, chloric acid, chlorous acid, and hypochlorous acid; Acid phosphates such as aluminum phosphate, acid magnesium phosphate and acid zinc phosphate; organic acids such as acetic acid, formic acid, propionic acid, oxalic acid, malonic acid, succinic acid, citric acid, malic acid, adipic acid, azelaic acid Carboxylic acids are mentioned. Among these, organic carboxylic acids are mentioned as an acid catalyst which improves the water resistance of the water-repellent powder obtained more. The organic carboxylic acids include acetic acid, but may be formic acid, propionic acid, oxalic acid, malonic acid, and the like. You may use these individually or in mixture of 2 or more types.

  By using an acid catalyst, the hydrolysis reaction of the polysiloxane compound and the silane monomer is promoted, and a sol can be obtained in a shorter time.

  The addition amount of an acid catalyst can be 0.001-0.1 mass part with respect to 100 mass parts of total amounts of a polysiloxane compound group and a silane monomer group.

  As the surfactant, a nonionic surfactant, an ionic surfactant, or the like can be used. You may use these individually or in mixture of 2 or more types.

  As the nonionic surfactant, for example, a compound containing a hydrophilic part such as polyoxyethylene and a hydrophobic part mainly composed of an alkyl group, a compound containing a hydrophilic part such as polyoxypropylene, and the like can be used. Examples of the compound containing a hydrophilic part such as polyoxyethylene and a hydrophobic part mainly composed of an alkyl group include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene alkyl ether and the like. Examples of the compound having a hydrophilic portion such as polyoxypropylene include polyoxypropylene alkyl ether, a block copolymer of polyoxyethylene and polyoxypropylene, and the like.

  Examples of the ionic surfactant include a cationic surfactant, an anionic surfactant, and an amphoteric surfactant. Examples of the cationic surfactant include cetyltrimethylammonium bromide and cetyltrimethylammonium chloride. Examples of the anionic surfactant include sodium dodecyl sulfonate. Examples of amphoteric surfactants include amino acid surfactants, betaine surfactants, amine oxide surfactants, and the like. Examples of amino acid surfactants include acyl glutamic acid. Examples of betaine surfactants include lauryldimethylaminoacetic acid betaine and stearyldimethylaminoacetic acid betaine. Examples of the amine oxide surfactant include lauryl dimethylamine oxide.

  These surfactants have the effect of reducing the difference in chemical affinity between the solvent in the reaction system and the growing siloxane polymer and suppressing phase separation in the wet gel formation process described later. To do.

  The addition amount of the surfactant depends on the type of the surfactant, or the type and amount of the polysiloxane compound and the silane monomer. For example, for 100 parts by mass of the total amount of the polysiloxane compound group and the silane monomer group, Although it can be 1-100 mass parts, it is good also as 5-60 mass parts.

  The thermohydrolyzable compound generates a base catalyst by thermal hydrolysis, renders the reaction solution basic, and promotes a sol-gel reaction in a wet gel generation process described later. Therefore, the thermohydrolyzable compound is not particularly limited as long as it is a compound that can make the reaction solution basic after hydrolysis. Urea; formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N -Acid amides such as methylacetamide and N, N-dimethylacetamide; cyclic nitrogen compounds such as hexamethylenetetramine and the like. Among these, urea is particularly easy to obtain the above-mentioned promoting effect.

  The amount of the thermally hydrolyzable compound added is not particularly limited as long as it is an amount that can sufficiently promote the sol-gel reaction in the wet gel generation step described later. For example, when urea is used as the thermohydrolyzable compound, the amount added can be 1 to 200 parts by mass with respect to 100 parts by mass of the total amount of the polysiloxane compound group and the silane monomer group. It may be 150 parts by mass. By making the addition amount 1 mass part or more, it becomes easier to obtain good reactivity, and by making it 200 mass parts or less, it becomes easier to further suppress the precipitation of crystals and the decrease in gel density.

  The hydrolysis in the sol production step depends on the type and amount of the polysiloxane compound, silane monomer, acid catalyst, surfactant and the like in the mixed solution, but for example, under a temperature environment of 20 to 60 ° C., 10 You may carry out for 24 minutes from a minute, and may carry out for 5 minutes to 8 hours in a 50-60 degreeC temperature environment. Thereby, the hydrolyzable functional group in a polysiloxane compound and a silane monomer is fully hydrolyzed, and the hydrolysis product of a polysiloxane compound and the hydrolysis product of a silane monomer can be obtained more reliably.

  However, when a thermohydrolyzable compound is added to the solvent, the temperature environment of the sol generation step may be adjusted to a temperature that suppresses hydrolysis of the thermohydrolyzable compound and suppresses gelation of the sol. . The temperature at this time may be any temperature as long as the hydrolysis of the thermally hydrolyzable compound can be suppressed. For example, when urea is used as the thermally hydrolyzable compound, the temperature environment of the sol generation step can be 0 to 40 ° C., and may be 10 to 30 ° C.

(Wet gel production process)
The wet gel generation step is a step in which the sol obtained in the sol generation step is gelled and then aged to obtain a wet gel. In this step, a base catalyst can be used to promote gelation.

  Examples of the base catalyst include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and cesium hydroxide; ammonium compounds such as ammonium hydroxide, ammonium fluoride, ammonium chloride, and ammonium bromide; Sodium phosphates such as sodium phosphate, sodium pyrophosphate, sodium polyphosphate; allylamine, diallylamine, triallylamine, isopropylamine, diisopropylamine, ethylamine, diethylamine, triethylamine, 2-ethylhexylamine, 3-ethoxypropylamine, diisobutylamine , 3- (diethylamino) propylamine, di-2-ethylhexylamine, 3- (dibutylamino) propylamine, tetramethylethylenediamine, t-butylamine, aliphatic amines such as ec-butylamine, propylamine, 3- (methylamino) propylamine, 3- (dimethylamino) propylamine, 3-methoxyamine, dimethylethanolamine, methyldiethanolamine, diethanolamine, triethanolamine; morpholine N-methylmorpholine, 2-methylmorpholine, piperazine and derivatives thereof, piperidine and derivatives thereof, and nitrogen-containing heterocyclic compounds such as imidazole and derivatives thereof. Among these, ammonium hydroxide (ammonia water) is excellent in that it has high volatility and does not easily remain in the water-repellent powder after drying, so that it is difficult to impair the water resistance, and is economical. You may use a base catalyst individually or in mixture of 2 or more types.

  By using a base catalyst, the dehydration condensation reaction and dealcoholization condensation reaction of the hydrolysis product of the polysiloxane compound group and silane monomer group in the sol can be promoted, and the sol is gelled in a shorter time. be able to. Thereby, a wet gel with higher strength (rigidity) can be obtained. In particular, since ammonia is highly volatile and hardly remains in the water-repellent powder, it is possible to obtain a water-repellent powder having more excellent water resistance by using ammonia as a base catalyst.

  The addition amount of a base catalyst can be 0.5-5 mass parts with respect to 100 mass parts of total amounts of a polysiloxane compound group and a silane monomer group, and is good also as 1-4 mass parts. By setting the addition amount to 0.5 parts by mass or more, gelation can be performed in a shorter time, and by setting the addition amount to 5 parts by mass or less, a decrease in water resistance can be further suppressed.

  The gelation of the sol in the wet gel generation step may be performed in a sealed container so that the solvent and the base catalyst do not volatilize. The gelation temperature can be, for example, 30 to 90 ° C., and may be 40 to 80 ° C. By setting the gelation temperature to 30 ° C. or higher, gelation can be performed in a shorter time, and a wet gel with higher strength (rigidity) can be obtained. Moreover, since it becomes easy to suppress volatilization of a solvent (especially alcohol) by making gelation temperature into 90 degrees C or less, it can gelatinize, suppressing volume shrinkage.

  The aging in the wet gel generation step may be performed in a sealed container so that the solvent and the base catalyst do not volatilize. By aging, the components of the wet gel are strongly bonded, and as a result, a wet gel having a high strength (rigidity) sufficient to suppress shrinkage during drying can be obtained. The aging temperature can be, for example, 30 to 90 ° C, and may be 40 to 80 ° C. By setting the aging temperature to 30 ° C. or higher, a wet gel with higher strength (rigidity) can be obtained, and by setting the aging temperature to 90 ° C. or lower, volatilization of the solvent (especially alcohols) can be easily suppressed. Therefore, it can be gelled while suppressing volume shrinkage.

  Since it is often difficult to determine the sol gelation end point, sol gelation and subsequent aging may be performed in a series of operations.

  The gelation time and the aging time vary depending on the gelation temperature and the aging temperature, but the total of the gelation time and the aging time can be, for example, 4 to 480 hours, and may be 6 to 120 hours. . By setting the total gelation time and aging time to 4 hours or more, a wet gel with higher strength (rigidity) can be obtained, and by setting it to 480 hours or less, the effect of aging can be more easily maintained.

  In order to reduce the density of the obtained water repellent powder or increase the average pore diameter, the gelation temperature and the aging temperature are increased within the above range, or the total time of the gelation time and the aging time is increased within the above range. You can do it. In addition, in order to increase the density of the obtained water repellent powder or reduce the average pore diameter, the gelation temperature and the aging temperature are reduced within the above range, or the total time of the gelation time and the aging time is within the above range. It can be shortened within.

(Wet gel grinding process)
In this step, the wet gel obtained in the wet gel production step is pulverized. The wet gel can be pulverized, for example, by placing the wet gel in a Hensial-type mixer or by performing a wet gel production process in the mixer and operating the mixer at an appropriate rotation speed and time. For simpler wet gel grinding, the wet gel is put into a sealable container, or a wet gel production process is performed in a sealable container, and a shaker such as a shaker is used. This can be done by shaking. In addition, you may adjust the particle diameter of a wet gel using a jet mill, a roller mill, a bead mill etc. as needed.

(Washing and solvent replacement process)
The washing and solvent replacement step includes a step of washing the wet gel obtained by the wet gel grinding step (washing step), and a step of replacing the washing liquid in the wet gel with a solvent suitable for the drying conditions (the drying step described later). It is a process which has (solvent substitution process). The washing and solvent replacement step can be performed in a form in which only the solvent replacement step is performed without performing the step of washing the wet gel, but the impurities such as unreacted substances and by-products in the wet gel are reduced, and more The wet gel may be washed from the viewpoint of enabling production of a highly pure water-repellent powder.

  In the washing step, the wet gel obtained in the wet gel production step is washed. The said washing | cleaning can be repeatedly performed using water or an organic solvent, for example. At this time, washing efficiency can be improved by heating.

  As organic solvents, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, methyl ethyl ketone, 1,2-dimethoxyethane, acetonitrile, hexane, toluene, diethyl ether, chloroform, ethyl acetate, tetrahydrofuran, methylene chloride , N, N-dimethylformamide, dimethyl sulfoxide, acetic acid, formic acid, and other various organic solvents can be used. You may use an organic solvent individually or in mixture of 2 or more types.

  In the solvent replacement step described below, a low surface tension solvent can be used to suppress gel shrinkage due to drying. However, low surface tension solvents generally have very low mutual solubility with water. Therefore, when using a low surface tension solvent in the solvent replacement step, examples of the organic solvent used in the washing step include hydrophilic organic solvents having high mutual solubility in both water and a low surface tension solvent. Note that the hydrophilic organic solvent used in the washing step can serve as a preliminary replacement for the solvent replacement step. Among the above organic solvents, examples of the hydrophilic organic solvent include methanol, ethanol, 2-propanol, acetone, and methyl ethyl ketone. Methanol, ethanol, methyl ethyl ketone and the like are excellent in terms of economy.

  The amount of water or organic solvent used in the washing step can be set to an amount that can sufficiently wash the solvent in the wet gel and wash it. The amount can be 3 to 10 times the amount of wet gel volume. The washing can be repeated until the moisture content in the wet gel after washing is 10% by mass or less with respect to the silica mass.

  The temperature environment in the washing step can be set to a temperature equal to or lower than the boiling point of the solvent used for washing.

  In the solvent replacement step, the solvent of the washed wet gel is replaced with a predetermined replacement solvent in order to suppress shrinkage in the drying step described later. At this time, the replacement efficiency can be improved by heating. Specific examples of the solvent for substitution include a low surface tension solvent described later in the drying step when drying under atmospheric pressure at a temperature lower than the critical point of the solvent used for drying. On the other hand, when performing supercritical drying, examples of the substitution solvent include ethanol, methanol, 2-propanol, dichlorodifluoromethane, carbon dioxide, and the like, or a solvent obtained by mixing two or more of these.

  Examples of the low surface tension solvent include a solvent having a surface tension at 20 ° C. of 30 mN / m or less. The surface tension may be 25 mN / m or less, or 20 mN / m or less. Examples of the low surface tension solvent include pentane (15.5), hexane (18.4), heptane (20.2), octane (21.7), 2-methylpentane (17.4), 3- Aliphatic hydrocarbons such as methylpentane (18.1), 2-methylhexane (19.3), cyclopentane (22.6), cyclohexane (25.2), 1-pentene (16.0); (28.9), toluene (28.5), m-xylene (28.7), p-xylene (28.3) and other aromatic hydrocarbons; dichloromethane (27.9), chloroform (27.2) ), Carbon tetrachloride (26.9), 1-chloropropane (21.8), 2-chloropropane (18.1) and other halogenated hydrocarbons; ethyl ether (17.1), propyl ether (20.5) ), Isop Ethers such as pyrether (17.7), butyl ethyl ether (20.8), 1,2-dimethoxyethane (24.6); acetone (23.3), methyl ethyl ketone (24.6), methyl propyl ketone (25.1), ketones such as diethyl ketone (25.3); methyl acetate (24.8), ethyl acetate (23.8), propyl acetate (24.3), isopropyl acetate (21.2), Examples include esters such as isobutyl acetate (23.7) and ethyl butyrate (24.6) (inside the surface tension is indicated at 20 ° C., and the unit is [mN / m]). Among these, aliphatic hydrocarbons (hexane, heptane, etc.) have low surface tension and excellent work environment. Among these, by using a hydrophilic organic solvent such as acetone, methyl ethyl ketone, or 1,2-dimethoxyethane, it can be used as the organic solvent in the washing step. Among these, a solvent having a boiling point of 100 ° C. or less at normal pressure may be used because it is easy to dry in the drying step described later. You may use said organic solvent individually or in mixture of 2 or more types.

  The amount of the solvent used in the solvent replacement step can be an amount that can sufficiently replace the solvent in the wet gel after washing. The amount can be 3 to 10 times the amount of wet gel volume.

  The temperature environment in the solvent replacement step can be set to a temperature not higher than the boiling point of the solvent used for the replacement. For example, when heptane is used, the temperature can be set to about 30 to 60 ° C.

(Drying process)
In the drying step, the pulverized wet gel that has been washed and solvent-substituted as described above is dried. Thereby, water-repellent powder can be finally obtained.

  The drying method is not particularly limited, and known normal pressure drying, supercritical drying, or freeze drying can be used. Among these, from the viewpoint of easy production of low-density water-repellent powder, normal drying is usually performed. Pressure drying or supercritical drying can be used. Further, atmospheric drying can be used from the viewpoint of being able to produce at low cost. In the present embodiment, the normal pressure means 0.1 MPa (atmospheric pressure).

  The water-repellent powder of this embodiment can be obtained by drying a wet gel that has been washed and solvent-substituted at a temperature below the critical point of the solvent used for drying under atmospheric pressure. Although the drying temperature varies depending on the type of the solvent substituted, it is preferably set to 20 to 80 ° C. in view of the fact that drying at a high temperature increases the evaporation rate of the solvent and may cause a large crack in the gel. it can. In addition, the said drying temperature is good also as 30-60 degreeC. Moreover, although drying time changes with the capacity | capacitances and drying temperature of a wet gel, it can be 4 to 120 hours. In the present embodiment, atmospheric pressure drying includes applying pressure within a range that does not inhibit productivity.

  The water-repellent powder of this embodiment can also be obtained by supercritically drying a wet gel that has been washed and solvent-substituted. Supercritical drying can be performed by a known method. Examples of the supercritical drying method include a method of removing the solvent at a temperature and pressure higher than the critical point of the solvent contained in the wet gel. Alternatively, as a method of supercritical drying, all or part of the solvent contained in the wet gel is obtained by immersing the wet gel in liquefied carbon dioxide, for example, under conditions of about 20 to 25 ° C. and about 5 to 20 MPa. And carbon dioxide having a lower critical point than that of the solvent, and then removing carbon dioxide alone or a mixture of carbon dioxide and the solvent.

  The water repellent powder obtained by such normal pressure drying or supercritical drying may be further dried at 105 to 200 ° C. for about 0.5 to 2 hours under normal pressure. This makes it easier to obtain a water-repellent powder having a low density and having small pores. The additional drying can be performed at 150 to 200 ° C. under normal pressure.

[Average particle size]
The average particle diameter D50 of the water-repellent powder of the present embodiment can be 1-1000 μm, but may be 3-700 μm, or 5-500 μm. When the average particle diameter D50 of the water repellent powder is 1 μm or more, it is easy to improve the formability and adhesion of the water repellent film to the object. In addition, the average particle diameter of water-repellent powder can be suitably adjusted with methods, such as a grinding | pulverization method, grinding | pulverization conditions, a sieve, and classification.

  The average particle diameter D50 of the water repellent powder can be measured by a laser diffraction / scattering method. For example, water repellent powder is added to a solvent (methanol) in a concentration range of 0.05 to 5% by mass, and the powder is dispersed by vibrating for 15 to 30 minutes with a 50 W ultrasonic homogenizer. Thereafter, about 10 mL of the dispersion is injected into a laser diffraction / scattering particle size distribution measuring apparatus, and the particle size is measured at 25 ° C. with a refractive index of 1.3 and zero absorption. The particle size at an integrated value of 50% (volume basis) in this particle size distribution is defined as the average particle size D50. As the measuring device, for example, Microtrac MT3000 (manufactured by Nikkiso Co., Ltd., product name) can be used.

[Compressive modulus]
The compression elastic modulus at 25 ° C. of the water repellent powder of the present embodiment can be 2.0 MPa or less, may be 1.5 MPa or less, may be 1.3 MPa or less, and may be 1.0 MPa or less. It may be. When the compression elastic modulus is 2 MPa or less, sufficient adhesion can be ensured when fixing the water-repellent powder to the object to be treated. In addition, the lower limit value of the compression elastic modulus is not particularly limited, but may be 0.05 MPa, for example. The compression elastic modulus can be measured using a micro compression tester “MCT-510” (manufactured by Shimadzu Corporation, product name).

<Water repellent treatment method using water repellent powder>
Next, a water repellent treatment method using the water repellent powder of this embodiment will be described. The water-repellent treatment method using the water-repellent powder is not particularly limited. For example, the subject can be subjected to the water-repellent treatment by the following method.

  In the water repellent treatment, the water repellent powder may be brought into direct contact with the surface to be treated of the object, or the water repellent treatment liquid containing the water repellent powder may be brought into contact with the surface to be treated of the object. Since the water-repellent powder of this embodiment has flexibility, the water-repellent part can be formed on the surface to be treated by disposing the water-repellent powder on the surface to be treated of the object.

  The water repellent treatment of the object using the water repellent powder of the present embodiment may be performed, for example, by a method in which the water repellent powder is in direct contact with the surface to be treated of the object. Specifically, after the water-repellent powder is placed on the surface to be treated, it is rubbed (rubbed) well, and the water-repellent treatment is performed on the surface to be treated by wiping off the excess water-repellent powder (forming a water-repellent part). be able to.

  The water-repellent treatment of the target object using the water-repellent treatment liquid containing the water-repellent powder of the present embodiment may be performed by a method mainly including a water-repellent treatment liquid preparation process, an application process, and a drying process. . Hereinafter, each process of the water-repellent treatment method using the water-repellent treatment liquid according to the present embodiment will be described.

(Production process of water repellent treatment liquid)
The water repellent treatment liquid according to this embodiment can be prepared by dispersing water repellent powder in an organic solvent. By using the water repellent treatment liquid, the water repellent portion can be uniformly formed on the target surface of the target object. The water-repellent part may be a film-like appearance (water-repellent film) in which a minute amount of water-repellent powder is deposited to a predetermined thickness, or a particle-like appearance in which a certain amount of water-repellent powder adheres on a flat surface (Water repellent particles) may also be used.

  Examples of the organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, methyl ethyl ketone, 1,2-dimethoxyethane, acetonitrile, heptane, hexane, toluene, diethyl ether, chloroform, ethyl acetate, tetrahydrofuran, Various organic solvents such as methylene chloride, N, N-dimethylformamide, dimethyl sulfoxide, acetic acid and formic acid can be used. You may use an organic solvent individually or in mixture of 2 or more types.

(Coating process)
An application process is a process of apply | coating a water repellent treatment liquid to a to-be-processed surface. In some cases, the surface to be treated may be dried after application to volatilize the solvent. By this step, a water repellent part can be formed on the surface to be processed. The water repellent treatment liquid may be applied to the entire surface to be processed, or may be selectively applied to a part of the surface to be processed.

  Although it does not specifically limit as a coating method, For example, a spin coat method, a dip coat method, a spray coat method, a flow coat method, a bar coat method, and a gravure coat method are mentioned. In particular, the spray coating method is preferable because a water repellent portion can be formed with a uniform thickness even on an uneven surface to be processed, the productivity is high, and the use efficiency of the water repellent powder is good. The coating method may be used alone or in combination of two or more.

  The water-repellent portion may be formed on the surface to be treated by applying or impregnating the water-repellent treatment liquid to another substrate (film, cloth or the like) in advance and then bringing it into contact with the surface to be treated for transfer. The application method can be freely selected according to the amount of water repellent treatment liquid used, the area of the surface to be treated, the characteristics, and the like.

  Although the material which comprises a to-be-processed surface is not specifically limited, For example, metal, ceramics, glass, plastics, and the material (composite material, laminated material, etc.) which combined these are mentioned. The water repellent treatment liquid can also be applied to paper, fiber, cloth, nonwoven fabric, rubber, leather and the like. In the case where the treated surface is dried and the solvent is volatilized after applying the water repellent treatment liquid, the material constituting the treated surface may be a water-soluble organic compound, a water-soluble inorganic compound, or the like. Among these, the material constituting the surface to be processed is preferably a transparent material such as glass or plastic.

  Examples of the metal include stainless steel, aluminum, copper, galvanized steel sheet, and iron. Examples of ceramics include alumina, barium titanate, boron nitride, and silicon nitride. Examples of the glass include ordinary soda lime glass, borosilicate glass, alkali-free glass, quartz glass, and aluminosilicate glass. Examples of the plastic include acrylic resins such as polymethyl methacrylate, aromatic polycarbonate resins such as polyphenylene carbonate, and aromatic polyester resins such as polyethylene terephthalate (PET).

  Examples of the water-soluble organic compound include glucose, sucrose, starch, polyacrylamide, polyvinyl alcohol, and methylcellulose. Examples of the water-soluble inorganic compound include water glass, sodium chloride, sodium phosphate, sodium carbonate, sodium vanadate, sodium borate, potassium chloride, potassium carbonate, and a sulfuric acid compound.

  After applying the water repellent treatment liquid, the adhesion of the water repellent part can be further improved by drying the treated surface and volatilizing the solvent. The drying temperature at this time is not particularly limited, and varies depending on the heat-resistant temperature of the surface to be processed, but may be, for example, 60 to 250 ° C or 120 to 180 ° C. By making the said temperature 60 degreeC or more, the outstanding adhesiveness can be achieved, and deterioration by a heat | fever can be suppressed by setting it as 250 degrees C or less.

(Drying process)
A drying process is a process of drying the to-be-processed surface in which the water repellent part was formed.

  Although it does not restrict | limit especially as a method of drying, For example, the well-known drying method under atmospheric pressure can be used. The drying temperature varies depending on the heat-resistant temperature of the surface to be processed. The drying temperature may be, for example, 20 to 250 ° C. or 60 to 180 ° C. from the viewpoint that the evaporation rate of the solvent is sufficiently high and the deterioration of the water repellent part is easily prevented. The drying time varies depending on the mass of the water repellent part and the drying temperature, but may be, for example, 1 to 24 hours.

  The thickness of the water repellent part is not particularly limited, and can be appropriately adjusted depending on the size of the water repellent powder, the method of forming the water repellent part, and the like. When processing a target object using the water-repellent processing liquid containing water-repellent powder, the thickness of the water-repellent part formed can be 1-1000 micrometers which is the particle size of water-repellent powder, for example. On the other hand, when using a method (such as a rubbing method) in which the water-repellent powder is in direct contact with the surface to be treated of the object, the water-repellent powder is pulverized to some extent, and the thickness of the water-repellent portion is, for example, 1 to 500 nm. can do.

The amount of water-repellent powder adhering to the surface to be treated is preferably 1 or more per 1 mm square. By using one or more, more excellent water repellency can be achieved. In addition, the adhesion amount of water-repellent powder can be calculated using a scanning electron microscope (SEM). For example, in the case of a water-repellent powder having an average particle size of 100 nm, a square area A (1.0 × 10 ⁻⁴ mm) having a length of 100 times the average particle size (1.0 × 10 ⁻² mm) as one side. ² ) is set. The number B (particles) of particles in the square is measured, and B / A is calculated. This is repeated 10 times, and the average value of the obtained B / A is defined as the amount of adhered particles.

  Since the water-repellent part formed on the surface to be treated by the water-repellent powder can achieve better water repellency, it can be an airgel. The airgel formed here is a porous body having nanometer-sized micropores. The airgel is considered to exhibit excellent water repellency because its surface has few hydroxyl groups and water does not easily enter micropores. In addition, since airgel has a large porosity, it is considered that a water repellent part having high transparency can be obtained because the water repellent part which is an airgel has a low refractive index.

  By the above water repellent treatment method using the water repellent powder of this embodiment, a water repellent portion having excellent water repellency and flexibility can be formed on the surface to be treated. A water repellent structure having such a water repellent portion can exhibit excellent water repellency and durability.

  Next, the present disclosure will be described in more detail by the following examples, but these examples do not limit the present invention in any way.

Example 1
[Preparation of water repellent powder 1]
40.0 parts by mass of carbinol-modified siloxane “X-22-160AS” (manufactured by Shin-Etsu Chemical Co., Ltd., product name) as a polysiloxane compound, and methyltrimethoxysilane “LS-530” (Shin-Etsu Chemical Co., Ltd.) as a silane monomer 60.0 parts by mass of a product made by the company and a product name (hereinafter abbreviated as “MTMS”), 120.0 parts by mass of water and 80.0 parts by mass of methanol are mixed, and 0.10 parts by mass of acetic acid is used as an acid catalyst. In addition, a sol was obtained by reacting at 25 ° C. for 8 hours. To the obtained sol, 40.0 parts by mass of 5% aqueous ammonia as a base catalyst was added and gelled at 60 ° C. for 8 hours, and then aged at 80 ° C. for 48 hours to obtain wet gel 1.

  The wet gel 1 was transferred to a plastic bottle, sealed, and then pulverized at 27000 rpm for 10 minutes using an extreme mill (manufactured by As One Co., Ltd., MX-1000XTS) to obtain a particulate wet gel 1. The obtained particulate wet gel 1 was immersed in 2500 parts by mass of methanol and washed at 60 ° C. for 12 hours. This washing operation was performed a total of three times while exchanging with fresh methanol. Next, the washed particulate wet gel was immersed in 2500 parts by mass of heptane, which is a low surface tension solvent, and solvent substitution was performed at 40 ° C. for 12 hours. This solvent replacement operation was performed three times in total while exchanging with new heptane. The washed and solvent-substituted particulate wet gel was dried under normal pressure at 40 ° C. for 96 hours and further dried at 150 ° C. for 2 hours. The dried gel was passed through a sieve (manufactured by Tokyo Screen Co., Ltd., opening 45 μm, wire diameter 32 μm) to obtain a water repellent powder 1 having a structure represented by the above general formula (1).

[Preparation of water repellent treatment liquid 1]
The water repellent treatment liquid 1 was obtained by dispersing 5.0 g of the water repellent powder 1 in 500.0 g of methyl ethyl ketone (MEK).

[Water repellent structure 1]
After dipping the slide glass S7213 (manufactured by Matsunami Glass Industrial Co., Ltd., product name) for 5 minutes in the water repellent treatment liquid 1, the dipped slide glass is dried at 120 ° C. for 1 hour under normal pressure to obtain water repellency. A structure 1 was obtained.

(Example 2)
[Preparation of water repellent powder 2]
200.0 parts by mass of water, 0.10 parts by mass of acetic acid, 20.0 parts by mass of CTAB and 120.0 parts by mass of urea were mixed, and 40.0 parts by mass of polysiloxane compound A and 60 parts of MTMS were mixed therewith. 0.0 part by mass was added and reacted at 25 ° C. for 2 hours to obtain a sol. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, in the same manner as in Example 1, a water-repellent powder 2 having a ladder structure including the structures represented by the general formulas (2) and (3) was obtained.

  The “polysiloxane compound A” was synthesized as follows. First, in a 1 liter three-necked flask equipped with a stirrer, a thermometer, and a Dimroth condenser, 100.0 parts by mass of hydroxy-terminated dimethylpolysiloxane “XC96-723” (product name, manufactured by Momentive), methyl 181.3 parts by mass of trimethoxysilane and 0.50 parts by mass of t-butylamine were mixed and reacted at 30 ° C. for 5 hours. Thereafter, this reaction solution was heated at 140 ° C. for 2 hours under reduced pressure of 1.3 kPa to remove volatile components, thereby obtaining a bifunctional alkoxy-modified polysiloxane compound (polysiloxane compound A) at both ends.

[Preparation of water-repellent treatment liquid 2]
The water-repellent treatment liquid 2 was obtained by dispersing 5.0 g of the water-repellent powder 2 with respect to 500.0 g of MEK.

[Water repellent structure 2]
After dipping the slide glass S7213 in the water repellent treatment liquid 2 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a water repellent structure 2.

(Example 3)
[Preparation of water repellent powder 3]
200.0 parts by mass of water, 0.10 parts by mass of acetic acid, 20.0 parts by mass of CTAB and 120.0 parts by mass of urea were mixed, and 20.0 parts by mass of X-22-160AS and MTMS were mixed. 60.0 parts by mass and 20.0 parts by mass of bistrimethoxysilylhexane were added and reacted at 25 ° C. for 2 hours to obtain a sol. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, in the same manner as in Example 1, a water repellent powder 3 having a structure represented by the general formula (1) was obtained.

[Preparation of water-repellent treatment liquid 3]
The water-repellent treatment liquid 3 was obtained by dispersing 5.0 g of the water-repellent powder 3 with respect to 500.0 g of MEK.

[Water repellent structure 3]
After dipping the slide glass S7213 in the water repellent treatment liquid 3 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a water repellent structure 3.

Example 4
[Preparation of water repellent powder 4]
200.0 parts by mass of water, 0.10 parts by mass of acetic acid, 20.0 parts by mass of CTAB and 120.0 parts by mass of urea were mixed, and 20.0 parts by mass of polysiloxane compound A and 60 parts of MTMS were mixed therewith. 0.0 part by mass and 20.0 parts by mass of bistrimethoxysilylhexane were added and reacted at 25 ° C. for 2 hours to obtain a sol. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, in the same manner as in Example 1, a water-repellent powder 4 having a ladder structure represented by the general formulas (2) and (3) was obtained.

[Preparation of water-repellent treatment liquid 4]
The water-repellent treatment liquid 4 was obtained by dispersing 5.0 g of the water-repellent powder 4 with respect to 500.0 g of MEK.

[Water repellent structure 4]
After dipping the slide glass S7213 in the water repellent treatment liquid 4 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a water repellent structure 4.

(Example 5)
[Preparation of water repellent powder 5]
200.0 parts by mass of water, 0.10 parts by mass of acetic acid, 20.0 parts by mass of CTAB and 120.0 parts by mass of urea were mixed, and 20.0 parts by mass of X-22-160AS was mixed with polysiloxane. 20.0 parts by mass of Compound A and 60.0 parts by mass of MTMS were added and reacted at 25 ° C. for 2 hours to obtain a sol. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, in the same manner as in Example 1, a water repellent powder 5 having a structure represented by the general formula (1) and a ladder structure represented by the general formulas (2) and (3) was obtained. .

[Preparation of water repellent treatment solution 5]
5.0 g of the water repellent powder 5 was dispersed in 500.0 g of MEK to obtain a water repellent treatment liquid 5.

[Water repellent structure 5]
After dipping the slide glass S7213 in the water repellent treatment liquid 5 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain the water repellent structure 5.

(Example 6)
[Preparation of water repellent powder 6]
200.0 parts by mass of water, 0.10 parts by mass of acetic acid, 20.0 parts by mass of CTAB and 120.0 parts by mass of urea were mixed, and dimethyldimethoxysilane KBM-22 (manufactured by Shin-Etsu Chemical Co., Ltd., 20.0 parts by mass of product name (hereinafter abbreviated as “DMDMS”), 20.0 parts by mass of polysiloxane compound A and 60.0 parts by mass of MTMS were added and reacted at 25 ° C. for 2 hours to obtain a sol. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, in the same manner as in Example 1, a water repellent powder 6 having a ladder structure represented by the general formulas (2) and (3) was obtained.

[Preparation of water-repellent treatment liquid 6]
The water repellent treatment liquid 6 was obtained by dispersing 5.0 g of the water repellent powder 6 with respect to 500.0 g of MEK.

[Water repellent structure 6]
The slide glass S7213 was dipped in the water repellent treatment liquid 6 for 5 minutes. Thereafter, the dip-treated slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a water-repellent structure 6.

(Example 7)
[Preparation of water repellent powder 7]
200.0 parts by mass of water, 0.10 parts by mass of acetic acid, 20.0 parts by mass of CTAB and 120.0 parts by mass of urea were mixed, and 40.0 parts by mass of polysiloxane compound B and 60 parts of MTMS were mixed therewith. 0.0 part by mass was added and reacted at 25 ° C. for 2 hours to obtain a sol. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, in the same manner as in Example 1, a water repellent powder 7 having a ladder structure represented by the general formulas (2) and (3) was obtained.

  The “polysiloxane compound B” was synthesized as follows. First, 100.0 parts by mass of XC96-723, 202.6 parts by mass of tetramethoxysilane and 0. 2 parts of t-butylamine in a 1 liter three-necked flask equipped with a stirrer, a thermometer and a Dimroth condenser. 50 parts by mass was mixed and reacted at 30 ° C. for 5 hours. Then, this reaction liquid was heated at 140 ° C. for 2 hours under a reduced pressure of 1.3 kPa to remove volatile components, thereby obtaining a trifunctional alkoxy-modified polysiloxane compound (polysiloxane compound B) at both ends.

[Preparation of water-repellent treatment liquid 7]
The water repellent treatment liquid 7 was obtained by dispersing 5.0 g of the water repellent powder 7 with respect to 500.0 g of MEK.

[Water repellent structure 7]
After dipping the slide glass S7213 in the water repellent treatment liquid 7 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a water repellent structure 7.

(Example 8)
[Preparation of water repellent powder 8]
100.0 parts by mass of water, 100.0 parts by mass of PL-2L (manufactured by Fuso Chemical Co., Ltd., spherical colloidal silica, average primary particle size: 20 nm), 20.0 parts by mass of CTAB and 120. part of urea. 0 parts by mass was mixed, 20.0 parts by mass of polysiloxane compound A, 20.0 parts by mass of DMDMS and 60.0 parts by mass of MTMS were added thereto, and reacted at 25 ° C. for 2 hours to obtain a sol. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, in the same manner as in Example 1, a water repellent powder 8 having a ladder structure represented by the general formulas (2) and (3) was obtained.

[Preparation of water repellent treatment liquid 8]
5.0 g of the water repellent powder 8 was dispersed in 500.0 g of MEK to obtain a water repellent treatment liquid 8.

[Water repellent structure 8]
After dipping the slide glass S7213 in the water repellent treatment liquid 8 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a water repellent structure 8.

Example 9
[Preparation of water repellent powder 9]
100.0 parts by weight of water, PL-5L (manufactured by Fuso Chemical Industry Co., Ltd., bowl-shaped colloidal silica, average primary particle size: 50 nm) is 100.0 parts by weight, CTAB is 20.0 parts by weight, and urea is 120 0.02 parts by mass was mixed, 20.0 parts by mass of polysiloxane compound A, 20.0 parts by mass of DMDMS and 60.0 parts by mass of MTMS were added thereto, and reacted at 25 ° C. for 2 hours to obtain a sol. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, in the same manner as in Example 1, a water-repellent powder 9 having a ladder structure represented by the general formulas (2) and (3) was obtained.

[Preparation of water repellent treatment liquid 9]
The water-repellent treatment liquid 9 was obtained by dispersing 5.0 g of the water-repellent powder 9 with respect to 500.0 g of MEK.

[Water repellent structure 9]
After dipping the slide glass S7213 in the water repellent treatment liquid 9 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a water repellent structure 9.

(Example 10)
After 1.0 g of the water-repellent powder 1 is placed on the slide glass S7213, the surface of the slide glass is rubbed multiple times with Kimcia towel manufactured by Crecia Co., Ltd. A water-repellent structure 10 was obtained (in Table 2, this water-repellent treatment method was described as “coating method”).

(Example 11)
A water repellent structure 11 was obtained in the same manner as in Example 10 except that the water repellent powder 2 was used.

(Example 12)
A water repellent structure 12 was obtained in the same manner as in Example 10 except that the water repellent powder 3 was used.

(Example 13)
A water repellent structure 13 was obtained in the same manner as in Example 10 except that the water repellent powder 6 was used.

(Example 14)
A water repellent structure 14 was obtained in the same manner as in Example 10 except that the water repellent powder 8 was used.

(Comparative Example 1)
[Production of comparative water-repellent powder 1]
200.0 parts by mass of water, 0.10 parts by mass of acetic acid, 20.0 parts by mass of CTAB and 120.0 parts by mass of urea were mixed, 100.0 parts by mass of MTMS was added thereto, and the mixture was added at 25 ° C. for 2 hours. A sol was obtained by reaction. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, a comparative water-repellent powder 1 was obtained in the same manner as in Example 1.

[Preparation of comparative water repellent treatment solution 1]
Comparative water repellent powder 1 was dispersed in 5.0 g of MEK 500.0 g to obtain a comparative water repellent treatment liquid 1.

[Comparative water-repellent structure 1]
After dipping the slide glass S7213 in the comparative water repellent treatment liquid 1 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a comparative water repellent structure 1.

(Comparative Example 2)
[Production of comparative water-repellent powder 2]
200.0 parts by mass of water, 0.10 parts by mass of acetic acid, 20.0 parts by mass of CTAB and 120.0 parts by mass of urea were mixed, and 100.0 parts by mass of tetraethoxysilane (TEOS) was added thereto. A sol was obtained by reacting at 25 ° C. for 2 hours. The obtained sol was gelled at 60 ° C. for 8 hours and then aged at 80 ° C. for 48 hours to obtain a wet gel. Thereafter, a comparative water-repellent powder 2 was obtained in the same manner as in Example 1.

[Preparation of comparative water repellent treatment liquid 2]
Comparative water repellent powder 2 was dispersed in 5.0 g of MEK 500.0 g to obtain a comparative water repellent treatment liquid 2.

[Comparative water-repellent structure 2]
After dipping the slide glass S7213 in the comparative water repellent treatment liquid 2 for 5 minutes, the dipped slide glass was dried at 120 ° C. for 1 hour under normal pressure to obtain a comparative water repellent structure 2.

(Comparative Example 3)
A comparative water-repellent structure 3 was obtained in the same manner as in Example 10 except that the comparative water-repellent powder 1 was used.

(Comparative Example 4)
A comparative water-repellent structure 4 was obtained in the same manner as in Example 10 except that the comparative water-repellent powder 2 was used.

  Table 1 shows Si raw materials (polysiloxane compounds, silane monomers, silica particles) and blending amounts in Examples and Comparative Examples.

[Various evaluations]
The water-repellent powder obtained in each Example and Comparative Example was evaluated according to the following conditions. The evaluation results are shown in Table 1 or Table 2.

(1) Measurement of FT-IR peak intensity “FT-IR / 6300” (manufactured by JASCO Corporation) was used as a Fourier transform infrared spectrometer to measure the infrared absorption spectrum of the water-repellent powder. The measurement was performed by measuring the baseline with air and then bringing the measurement sample (water repellent powder 0.01 g) into close contact with the prism portion of the ATR unit. The measurement conditions were ATR in the measurement mode, 400 to 4000 cm ^{−1 in the} measurement wavenumber range, and 128 integrations. In the obtained spectrum data, the peak intensity at 1270 cm ⁻¹ was calculated when the peak intensity at a wave number of 1070 cm ⁻¹ was defined as 1.0.

For example, FIG. 3 is a diagram showing infrared absorption spectra of the water repellent powder 2, the water repellent powder 6, the comparative water repellent powder 1, and the comparative water repellent powder 2. From FIG. 3, it can confirm that the peak intensity of 1270 cm < ^-1 > which concerns on the water repellent powders 2 and 6 exists in the range of 0.2-0.7. On the other hand, it can be confirmed that the peak intensity of the comparative water-repellent powder 1 is not in the above range. In addition, it can confirm that the comparative water repellent powder 2 does not have a peak in the position of 1270 cm < ^-1 >. For the comparative water-repellent powder 2, the strength at a position of 1270 cm ⁻¹ was calculated.

(2) Measurement of signal area ratio concerning silicon-containing bonding units Q, T and D Measurement was performed using “FT-NMR AV400WB” (product name, manufactured by Bruker BioSpin Corporation) as a solid ²⁹ Si-NMR apparatus. It was. The measurement conditions were: measurement mode: DD / MAS method, probe: 4 mmφ CPMAS probe, magnetic field: 9.4 T, resonance frequency: 79 Hz, MAS rotation speed: 6 kHz, delay time: 150 seconds. As a standard sample, sodium 3-trimethylsilylpropionate was used.

The measurement was performed by filling the probe with water-repellent powder packed in a ZrO ₂ rotor. In the spectrum analysis, the line broadening factor was set to 2 Hz, and the signal area ratio (Q + T: D) relating to the obtained silicon-containing binding units Q, T, and D was determined.

(3) Compression elastic modulus As a measuring device, a micro compression tester “MCT-510” (manufactured by Shimadzu Corporation, product name) was used. Water repellent powder was set between the upper platen and the lower platen arranged in parallel, and compression was performed at a load speed of 0.0892 mN / sec. The measurement was terminated when a load exceeding 4.9 mN was applied or when the measurement sample was destroyed. The compressive elastic modulus was calculated from the compressive strain and compressive stress as follows.

Here, the compressive strain ε can be obtained from the following equation. In the formula, Δd represents the displacement (mm) of the thickness of the measurement sample due to the load, and d1 represents the thickness (mm) of the measurement sample before the load is applied.
ε = Δd / d1

The compressive stress σ (MPa) can be obtained from the following equation. In the formula, F represents the compressive force (N), and A represents the cross-sectional area (mm ² ) of the measurement sample before applying a load.
σ = F / A

The compression elastic modulus E (MPa) can be obtained from the following equation, for example, when the compression force is in the range of 0.1 to 0.2N. In the formula, σ ₁ indicates a compressive stress (MPa) measured at a compressive force of 0.1 N, σ ₂ indicates a compressive stress (MPa) measured at a compressive force of 0.2 N, and ε ₁ indicates a compressive stress. The compressive strain measured at σ ₁ is shown, and ε ₂ shows the compressive strain measured at the compressive stress σ ₂ .
E = (σ ₂ −σ ₁ ) / (ε ₂ −ε ₁ )

(4) Measurement of contact angle The water-repellent structures obtained in each Example and Comparative Example were dried at 105 ° C. for 1 hour to obtain a measurement sample. Next, using a contact angle meter DMs-401 manufactured by Kyowa Interface Science Co., Ltd., 2 μL of ultrapure water droplets were dropped and the contact angle after 5 seconds was measured. The measurement was performed 5 times, and the average value was taken as the water contact angle.

(5) Abrasion resistance test In the abrasion resistance test, a Kim Towel manufactured by Crecia Co., Ltd. was rubbed against the surface of the water-repellent structure several times, and then dried at 105 ° C. for 1 hour to obtain a measurement sample. The contact area of the Kim towel here was 20 mm × 50 mm, and the load was 0.1 kg / cm ² . Next, using a contact angle meter DMs-401 manufactured by Kyowa Interface Science Co., Ltd., 2 μL of ultrapure water droplets were dropped, and the contact angle after 5 seconds was measured at room temperature. The measurement was performed 5 times, and the average value was taken as the water contact angle.

  From Table 2, the water-repellent structure having the water-repellent part formed from the water-repellent powder of the example has a large water contact angle and good water repellency compared to the water-repellent structure of the comparative example, It can be confirmed that it has excellent flexibility. Further, as apparent from the results of the abrasion resistance test, the water-repellent structures of the examples are superior in durability and can maintain good water repellency as compared with the water-repellent structures of the comparative examples.

  L: circumscribed rectangle, P: silica particles.

Claims (6)

In the infrared absorption spectrum measured using Fourier transform infrared spectroscopy, when the peak intensity at a wave number of 1070 cm ⁻¹ derived from the network structure of Si—O—Si bond is defined as 1.0, Si—CH ₃ A water-repellent powder having a peak intensity in the vicinity of a wave number of 1270 cm ⁻¹ derived from the structure of 0.2 to 0.7. In the solid ²⁹ Si-NMR spectrum measured using the DD / MAS method, when the silicon-containing binding units Q, T and D are defined as follows, the signal area derived from Q and T, and the signal derived from D A water-repellent powder having an area ratio Q + T: D of 1: 0.01 to 1: 0.50.
Q: A silicon-containing bond unit having four oxygen atoms bonded to one silicon atom.
T: A silicon-containing bond unit having three oxygen atoms bonded to one silicon atom and one hydrogen atom or monovalent organic group.
D: A silicon-containing bond unit having two oxygen atoms bonded to one silicon atom and two hydrogen atoms or two monovalent organic groups.
[However, the organic group is a monovalent organic group in which an atom bonded to a silicon atom is a carbon atom. ] A water-repellent powder having a structure represented by the following general formula (1).
[In Formula (1), R ¹ and R ² each independently represent an alkyl group or an aryl group, and R ³ and R ⁴ each independently represent an alkylene group. ] A water-repellent powder having a ladder-type structure including a support portion and a bridge portion, wherein the bridge portion is represented by the following general formula (2).
[In Formula (2), R ⁵ and R ⁶ each independently represents an alkyl group or an aryl group, and b represents an integer of 1 to 50. ] The water-repellent powder according to claim 4, which has a ladder structure represented by the following general formula (3).
[In Formula (3), R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group, a and c each independently represent an integer of 1 to 3000, and b represents 1 to 50 Indicates an integer. ]]   The water repellent powder according to any one of claims 1 to 5, wherein the average particle diameter D50 is 1 to 1000 µm.