JPH1121510A - Silicone resin for forming water-repellent coating film and its composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicone resin which can form water-repellent smooth coating films and its composition. SOLUTION: This resin has an average structure represented by the formula: [R<1> 2 R<2> SiO1/2 ]a [R<1> 2 SiO2/2 ]b [R<3> R<2> SiO2/2 ]c [R<3> SiO3/2 ]d [R<1> is a 1-5C alkyl; R<2> is a 1-5C alkoxyl; R<3> is a 1-5C alkyl or aromatic hydrocarbon group; a<=0; b>0; c>0; d>0; a+b+c+d=1; (a+b)/(c+d)=0.24-4.0; and (a+c)/(a+b+c+ d)=0.05-0.40]. This is prepared by hydrolytically condensing compounds represented by the formulas: R<3> X3 [R<3> is as defined above; and X is a halogen] and Y(SiR<1> 2 O)c SiR<1> 2 Y [Y is a halogen or the like; R<1> is as defined above; and 0<=e<=300] in a two-phase medium comprising an oxygenic organic solvent and water. It is also possible to add a curing catalyst to the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silicone resin for forming a water-repellent film for forming a water-repellent smooth film.

[0002]

2. Description of the Related Art JP-A-48-39382 discloses a particle-containing composition which is coated on various substrates and exhibits water repellency.
JP-A-3-215570, JP-A-3-24499
No. 6, JP-A-4-45181 and the like are known.

[0003] The technique described in JP-A-48-39382 is based on a technique of coating (a) a fine powder having an average particle diameter of 2 μm or less and (b) a hydrophobic substance having a contact angle of 90 ° or more on a substrate surface. The present invention relates to water repellency of a substrate surface on which a hydrophobic fine powder layer having an average particle size of 5 to 10 μm is formed.

The technique described in JP-A-3-215570 is selected from the group consisting of (a) a hydrophobic fine powder having a surface tension of 32 dyne / cm or less and (b) a silicone resin, a fluororesin, an epoxy resin, and a polyimide resin. And water-repellent paints comprising one or more resins having a water absorption of 0.5% or less.

The technique described in JP-A-3-244996 discloses a solution of (a) an inorganic or organic powder having a porous shape and a particle size of 4 μm or less and (b) a silicone-based or fluorine-based resin compound. And a water-repellent coating composition comprising:

The technique described in Japanese Patent Application Laid-Open No. 4-45181 uses a three-dimensionally crosslinked product as a structural unit and has an R / Si ratio of 1.7.
The present invention relates to a water-repellent coating composition comprising a solution containing a silicone-based resin having a particle size of less than and inorganic fine particles having a surface subjected to a hydrophobic treatment.

Further, the present inventor has disclosed in Japanese Patent Laid-Open No.
In JP-A-87-87, (a) hydrophobizing treatment is carried out with a hydrophobizing agent having an organic group, and the hydrophobizing treatment rate (carbon content)
15 to 75% by weight of a hydrophobized substance having a content of 2.7% by weight or more
And (b) 25 to 85% by weight of a binder.

Each of these techniques is a composition comprising (a) hydrophobic particles and (b) a resin binder. As described above, in the water-repellent coating composed of (a) the hydrophobic particles and (b) the resin binder, water droplets tend to roll down. This is expected to be due to the fact that the surface of the water-repellent coating becomes uneven due to the presence of the hydrophobic fine powder, which retains a large amount of the air layer, and the synergistic effect of low surface tension.

However, when a member having such a type of water-repellent coating forms a heat exchanger, for example,
The water droplets to be rolled down are condensed water droplets generated by condensation, and the condensed water droplets are generated from inside the concave portion of the surface of the water-repellent coating, causing capillary condensation, and the effect of unevenness can not be exhibited, so the water-repellent performance is remarkable descend. When a water-repellent coating is formed on a member whose fins and plates are formed at minute intervals as in a heat exchanger, the water-repellent performance is more remarkably reduced, and the water-repellent film does not fall due to a reduced unevenness effect. Since the water droplets attached to the members are sandwiched between the two members and are prevented from falling, the deterioration of the water repellency is accelerated. In the water-repellent coating composed of (a) hydrophobic particles and (b) a resin binder, in order to improve the water-repellent effect,
A large amount of particles must be contained in the composition, and the large number of particles causes a decrease in the strength of the coating, resulting in a decrease in durability.

[0010] On the other hand, Japanese Patent Application No. Hei.
The invention of -347829 relates to a composition comprising a silicone resin comprising (R ₂ SiO _2/2 ) units and (RSiO _3/2 ) units which do not contain a fine particle filler, and a polydialkylsiloxane. is there. Water droplets deposited on the surface of this type of water repellent coating tend to slide down rather than roll down. In addition, the water-repellent coating has a smooth surface and does not cause capillary condensation.There is little decrease in water-repellency against condensed water droplets.Because of the sliding characteristics, water droplets sandwiched between adjacent members also involve other water droplets. There is a tendency to fall. Furthermore, since it does not contain fine particles, the durability of the coating is improved as compared with the water-repellent coating composed of (a) the hydrophobic particles and (b) the resin binder, and as a result, the durability of the water-repellent performance is also improved. Things.

[0011]

SUMMARY OF THE INVENTION The aforementioned Japanese Patent Application No. 7-347.
In the invention of No. 829, a good water-repellent performance can be obtained particularly in condensed water droplets by using a composition comprising a specific silicone resin and a polyalkylsiloxane without containing a filler of fine particles. However, in order to obtain water repellency equivalent to this, the composition is not limited to the above composition, and a certain amount or more of a bifunctional diorganosilyl group or diorganosiloxy unit is introduced into the organosilsesquioxane structure. It was confirmed that when silicone resin was used, it could be realized alone. An object of the present invention is to provide these silicone resins for forming a water-repellent film.

[0012]

Means for Solving the Problems The silicone resin of the present invention has an average structure represented by a general formula:

[R¹ _TwoR^TwoSiO_1/2]_a[R¹ _TwoSiO
_2/2]_b[R^TwoR^ThreeSiO_2/2]_c[R ^ThreeSiO_3/2]
_dThis is indicated by (1).

Here, R ¹ is each independently a methyl group,
Examples thereof include an alkyl group having 1 to 5 carbon atoms such as an ethyl group, and a methyl group is preferable. R ² is independently a hydroxyl group or an alkoxy group having 1 to 5 carbon atoms such as a methoxy group or an ethoxy group, and is preferably a hydroxyl group, a methoxy group or an ethoxy group. R ³ is independently an alkyl group having 1 to 5 carbon atoms such as a methyl group or an ethyl group, or an aromatic hydrocarbon group such as a phenyl group. a, b, c and d satisfy the following conditions. 1) a + b + c + d = 1 (where a is 0 or a positive number and b, c, and d are positive numbers) 2) 0.25 ≦ (a + b) / (c + d) ≦ 4.0 3) 0 .05 ≦ (a + c) / (a + b + c + d) ≦ 0.
40

Here, the value of (a + b) / (c + d) is 0.
If it is less than 25, the water-developing effect is insufficient, and if it is more than 4, the strength of the coating tends to decrease. This value is more preferably 0.3 ≦ (a + b) / (c + d) ≦ 3. The value of (a + c) / (a + b + c + d) represents the ratio of a unit having a silanol group and / or an alkoxysilyl group in the silicone resin for forming a water-repellent film of the present invention. When the value is less than the above range, the curability becomes insufficient. May be reduced. Although the molecular weight of the silicone resin for forming a water-repellent film of the present invention is not particularly limited, a range which can be practically used in various applications is usually selected. Examples of such a range include a number average molecular weight of 380 to 1,500,000 and a weight average molecular weight of 500 to 5,000,000.

From the viewpoints of water repellency and the strength of the cured film, it is desirable that the silicone resin having an average structure represented by the general formula (1) satisfies the following conditions. It contains at least a polydimethylsiloxane unit, and the average degree of polymerization of the polydimethylsiloxane unit is 5 to 1
000. In one molecule, the ratio of the number of units of the following (1) to the number of units of the following (2) is 1 or more (however, this does not apply when the unit of the following (2) does not exist). (1) Polydimethylsiloxane unit of [(CH ₃ ) ₂ SiO _2/2 ] _m (m ≧ 2) (2) Dimethyl siloxane unit of [(CH ₃ ) ₂ SiO _2/2 ] _m (m = 1) ( 0.3 ≦ (a + b) / (c + d) ≦ 3.

A unit having a functional group other than the substituents R ^{1 to} R ³ set in the silicone resin for forming a water-repellent film of the present invention or a monofunctional unit (R ⁴ SiO _1/2 ) (where R ⁴ is It represents a hydrocarbon group such as a methyl group, an ethyl group, or a phenyl group), and may contain some tetrafunctional (SiO _4/2 ) units. However, their existence is not denied as long as they do not impair the characteristic properties.

For the production of the silicone resin for forming a water-repellent film represented by the above formula (1) of the present invention, a general silicone resin production method can be used. As the production method, (a) an aromatic hydrocarbon solvent or an oxygen-containing organic solvent or the like and water are used as a mixed solvent, and an organohalosilane and a diorganopolysiloxane having a functional group at both ends are added thereto; Manufacturing method, (b)
The organohalosilane is polymerized by heating and stirring in the above mixed solvent, and the obtained silicone resin is subjected to a condensation reaction in the above mixed solvent in the presence of a catalyst with a difunctional organosilane or a bifunctional diorganosiloxane. And (c) alkoxysilane-forming an organohalosilane in an alcohol solvent, and using the organoalkoxysilane and a catalyst in the same steps as in the above (a) and (b). However, the present invention is not limited to these. In general, it is preferable to use the oxygen-containing organic solvent other than the alcohol-based one by the method (a) because the silicone resin can be manufactured without causing gelation.

A particularly preferred method for producing the water-repellent silicone resin represented by the formula (1) of the present invention is a two-phase reaction system comprising the following (d) and (e): ) Hydrolysis and condensation. (D) The following or: an oxygen-containing organic solvent; a mixed solvent comprising an oxygen-containing organic solvent and a hydrocarbon solvent (however, the proportion of the hydrocarbon solvent contained in the mixed solvent is 50% by volume or less); respect halogen atom 1 mol in (a) and (B), water with or without salt of a weak acid with water-soluble inorganic base or buffering capacity 1.8 gram equivalent or less, (a) formula R ³ Six ₃ (R ³ has the same meaning as above,
X is a halogen atom. Organotrihalosilane represented by); (B) formula _{^{Y (SiR 1 2 O) e}} SiR 1 2 Y (Y is a halogen atom, hydroxyl group, at least one selected from hydrogen, e is positive for 0 or 300 or less A bifunctional diorganosilane or a diorganopolysiloxane having a functional group at both terminals.

Preferred examples of such a production method include the following. (1) A two-phase reaction system consisting of the above (d) and (e) is formed, and a mixture of the above (A) and (B) or a solution in which (A) and (B) are dissolved in the above (d) To conduct the reaction by dropping. (2) A solution obtained by dissolving the components (A) and (B) in the component (d) is added dropwise to the aqueous phase of the component (e).
A method of performing a reaction in a phase reaction system. (3) The solution obtained by dissolving the above (A) and (B) in the above (d) and the above (e) are simultaneously dropped into an empty reaction vessel, and the resultant mixture is reacted in a two-phase reaction system. Method. (4) A two-phase reaction system of (d) and (e) in which (B) in which Y is at least one selected from a hydroxyl group and hydrogen is formed, and the above (A) or (d) contains ( A method in which a reaction in which A) is dissolved is performed dropwise. Alternatively, only (A) may be hydrolyzed by the methods (1), (2), and (3), and then (B) may be dropped and reacted.

The reaction temperature is suitably in the range of room temperature (20.degree. C.) to 120.degree. C., preferably about 40 to 100.degree.

The fact that water and the organic solvent form two phases means that water and the organic solvent are not mixed and a uniform solution is not obtained. The organic phase and the aqueous phase may be present in such a manner that the two phases form an upper layer and a lower layer by lowering the stirring speed, and a state of having a wide flat interface between them is maintained. May be expressed as "forming two layers"), and the two layers may not be maintained by vigorous stirring. However, from a practical point of view, the latter which does not require careful control of the stirring speed is preferred.

When X of halosilane (A) and Y of starting material (B) are halogen atoms, Y is preferably bromine, chlorine, and more preferably chlorine. E in (B) is a positive number of 0 or 300 or less, that is, a difunctional diorganosilane or a diorganopolysiloxane having a functional group at both terminals. When it is a diorganopolysiloxane, it may contain a molecular weight distribution, a branched structure, a cyclic compound, or a side chain functional group in a range produced in an industrial production method or the like.

The organic solvent used in this production method may dissolve (A) and (B) and may be slightly dissolved in water, but an oxygen-containing organic solvent S capable of forming two phases with water is used. 5 with respect to the total amount of the oxygen-containing organic solvent S
0% by volume or less of the hydrocarbon solvent T may be contained.
If the content of the hydrocarbon solvent T is larger than this, the amount of gel formed increases, the yield of the target product decreases, and it may not be practical. Alternatively, if the content of the hydrocarbon solvent T is large, the desired physical properties of the cured product may not be obtained. As the organic solvent, a solvent which is insoluble in water indefinitely and which is immiscible with an aqueous solution of water-soluble inorganic chlorine or a salt of a weak acid having a buffering ability can be used.

Examples of the oxygen-containing organic solvent S include ketone solvents such as methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, acetylacetone and cyclohexanone;
Ether solvents such as diethyl ether, dinormal propyl ether, dioxane, diethylene glycol dimethyl ether and tetrahydrofuran; ester solvents such as ethyl acetate, butyl acetate and butyl propionate; n-
Examples include alcohol solvents such as butanol and hexanol, but are not limited thereto. However, in order to obtain the desired physical thermal stability of the cured product, it is preferable not to use an alcohol solvent. These solvents may be used as a mixture of two or more kinds. Examples of the hydrocarbon solvent T include aromatic hydrocarbon solvents such as benzene, toluene, and xylene; aliphatic hydrocarbon solvents such as hexane and heptane; and halogenated hydrocarbon solvents such as chloroform, trichloroethylene, and carbon tetrachloride. However, the present invention is not limited to these. The amount of the organic solvent used is not particularly limited, but preferably the total amount of (A) and (B) is 100%.
It is in the range of 50 to 2,000 parts by weight based on parts by weight. The organic solvent is 5 parts by weight based on 100 parts by weight of the total of (A)
If the amount is less than 0 parts by weight, it is insufficient to dissolve the formed silicone resin, which may cause gelation. If the amount is more than 2,000 parts by weight, hydrolysis and condensation do not proceed promptly, resulting in low molecular weight. A silicone resin having poor storage stability is obtained. The amount of water used is not particularly limited, but is preferably in the range of 10 to 3000 parts by weight based on 100 parts by weight of the total of (A) and (B).

The aqueous phase may be added with a water-soluble inorganic base or a salt of a weak acid having a buffering ability, which suppresses the acidity due to hydrogen halide generated from the halosilane. It is possible.

Examples of the water-soluble inorganic base include water-soluble alkalis such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide. Carbonates such as sodium, potassium carbonate, calcium carbonate and magnesium carbonate; hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate; oxalates such as potassium bis (oxalate) trihydrogen; potassium hydrogen phthalate; sodium acetate; But phosphates such as disodium hydrogen phosphate and potassium dihydrogen phosphate, borates such as sodium tetraborate, and the like, but are not limited thereto. Further, these amounts are desirably not more than 1.8 gram equivalents to 1 mol of the total halogen atoms of the halogen in the halosilane molecule used and when Y in (B) is a halogen. That is, the amount is desirably 1.8 times or less the amount that just neutralizes the hydrogen halide generated when the halosilane or the like is completely hydrolyzed. These water-soluble inorganic bases or salts of weak acids having a buffering ability may be used as a mixture of two or more kinds within the above-mentioned quantitative range.

The silicone resin for forming a film of the present invention can be cured, and the curing can be carried out only by heating, but a curing catalyst and / or a crosslinking agent can also be used.

Examples of the curing catalyst include tin diacetate, tin dioctylate, tin dilaurate, tin tetraacetate, dibutyl tin diacetate, dibutyl tin dioctylate, dibutyl tin dilaurate, dibutyl tin dioleate, dimethoxy dibutyl tin,
Tin compounds such as dibutyltin oxide, dibutyltin benzylmaleate, bis (triethoxysiloxy) dibutyltin, diphenyltin diacetate; tetramethoxytitanium;
Tetraethoxytitanium, tetra-n-propoxytitanium, tetra-i-propoxytitanium, tetra-n-butoxytitanium, tetra-i-butoxytitanium, tetrakis (2-ethylhexoxy) titanium, di-i-propoxybis (ethylacetoacetate) ) Titanium, titanium dipropoxybis (acetylacetonate) titanium, di-i-
Propoxybis (acetylacetonato) titanium, dibutoxybis (acetylacetonato) titanium, tri-i
Titanium compounds such as propoxyallyl acetate titanium, titanium isopropoxyoctylene glycol, bis (acetylacetonato) titanium oxide; lead diacetate, lead bis (2-ethylhexanoate), lead dineodecanoate, lead tetraacetate, tetrakis ( Lead n-propionate), zinc diacetate, zinc bis (2-ethylhexanoate), zinc dinedecanoate, zinc diundecenoate, zinc dimethacrylate, iron diacetate, zirconium tetrakis (2-ethylhexanoate), tetrakis ( Metal fatty acids such as zirconium (methacrylic acid) and cobalt diacetate; aminopropyltrimethoxysilane, N- (2-aminoethyl) -3
-Aminopropyltrimethoxysilane, tetramethylguanidine, tetramethylguanidylpropyltrimethoxysilane, tetramethylguanidylpropyldimethoxysilane, tetramethylguanidylpropyltris (trimethylsiloxane) silane, 1,8-diazabicyclo [5 .4.0. -7-Undecene, di-n-hexylamine, triethanolamine, dicyclohexylamine, di-n-octylamine, triethylamine, diethylamine, triethylbenzylamine, ethylenediamine, diethylenetriamine, amino group-containing compounds such as triethylenetetraamine, etc. However, the present invention is not limited to these. Usually, silicone resin 10
It is used in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight based on 0 parts by weight.

Examples of the crosslinking agent include the following compounds.

[0031]

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[0032]

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The crosslinking agent is usually used in an amount of 0.1 to 80 parts by weight, preferably 1 to 70 parts by weight, based on 100 parts by weight of the silicone resin.
Used in parts by weight. The curing temperature is 20 to 350 ° C, preferably 20 to 250 ° C, regardless of whether a curing catalyst or a crosslinking agent is used. If it exceeds 350 ° C., siloxane may be decomposed. In the case of curing only by heating, the temperature is 50 ° C to 350 ° C, preferably 8 ° C.
0 ° C to 250 ° C. If the temperature is lower than 50 ° C., the reaction does not proceed sufficiently. If it exceeds 350 ° C., siloxane may be decomposed.

Solvents for dissolving the silicone resin or the composition of the present invention include aromatic hydrocarbon solvents such as benzene, toluene, and xylene; ether solvents such as diethyl ether and tetrahydrofuran; alcohol solvents such as butanol and hexanol; Ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and butyl acetate, chloroform,
Halogenated hydrocarbon solvents such as trichloroethylene and carbon tetrachloride; saturated hydrocarbon solvents such as hexane and n-octane; silane solvents such as trimethylmethoxysilane and dimethyldimethoxysilane; and volatile silicone solvents such as hexamethyldisiloxane. It is exemplified, but not limited to these.

When the composition of the present invention is used by dissolving it in the solvent, the solvent is used in an amount of 0 to 100,000 parts by weight, preferably 0 to 1 part by weight, per 100 parts by weight of the composition of the present invention.
Used in 0000 parts by weight.

The silicone resin of the present invention is used by applying or impregnating a substrate requiring water repellency by an appropriate means to form a film. Upon application or impregnation, it is possible to adjust the concentration by diluting with a solvent in order to obtain a suitable film-forming property as described above. As means for coating and impregnating, dip coating and impregnating methods, roll coating, flow coating, brush coating, spraying, and the like can be used. There is no particular limitation on the film thickness of the film formed on the substrate, but the film is formed with a thickness of, for example, 0.1 to 30 μm.

The object of the substrate to which the silicone resin for forming a water-repellent film of the present invention is applied is not particularly limited, and may be metal, glass, plastic, inorganic material, rubber,
The present invention can be applied to substrates made of various substances such as fibers. Basically, items, materials, parts, etc. that require water repellency, such as heat exchangers, architectural glass, kitchens, washrooms,
It is applied to places that are wet or humid, such as bathrooms.

[0038]

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

Example 1 400 mL of water and 300 mL of methyl isobutyl ketone were added to a reaction vessel equipped with a reflux condenser, a dropping funnel, and a stirrer, and vigorously stirred so as not to form two layers. 26.25 g of polydimethylsiloxane having an average degree of polymerization of 55 having hydroxyl groups was added, further stirred, and placed in an ice bath. When the temperature of the mixture in the reaction vessel reached 10 ° C., a solution of 123.75 g (0.828 mol) of methyltrichlorosilane dissolved in 100 mL of methyl isobutyl ketone was slowly dropped from the dropping funnel. At this time, the temperature of the reaction mixture rose to 17 ° C. After the addition was completed, the reaction mixture was heated and stirred for 1 hour on a 60 ° C. oil bath. After the completion of the reaction, the organic layer was washed until the washing water became neutral, and then the organic layer was dried using a desiccant. After removing the desiccant, the solvent was distilled off under reduced pressure, and vacuum drying was performed for two days and night to obtain a silicone resin as a wax-like solid. The molecular weight distribution of this silicone resin was measured by GPC (using HLC-8020 manufactured by Tosoh Corporation, and using TSKge1GMHXL-L + G1000HXL (trademark) manufactured by Tosoh Corporation as a column and using chloroform as a solvent).
The weight average molecular weight in terms of standard polystyrene was 5,000, and the number average molecular weight was 970. Also ²⁹ SiNM
R spectrum (measured by Bruker ACP-300)
The value of the molar ratio of diorganosiloxy units to monoorganosiloxy units, ie, (a + b) / (c + d), is 0.43, and the molar amount of silanol to 1 mol of silicon in organosiloxy units, ie, (a + c) /
The value of (a + b + c + d) was 0.213.

1 g of this silicone resin was dissolved in 10 g of isopropyl ether, and 10 mg of dibutyltin acetate was added thereto.
Flow coated on ISA-1050), 150
Cured in an oven at ℃ for 1 hour.

The water repellency of the coating thus obtained was determined by the following method. The aluminum plate on which the coating was formed was placed horizontally, and various amounts of distilled water were dropped on the surface of the coating with a micropipette, and the water droplets were allowed to stand. With one side of the aluminum plate in contact with the desk within 10 to 20 seconds after dropping the water, lift the other side up and set the aluminum plate perpendicular to the desk to see if the water drop falls by 5 mm or more within one minute. Observed. This measurement was performed at arbitrary 10 locations on the coating formed on the aluminum plate, and the minimum amount of water droplets that were confirmed to have dropped at 8 or more locations is shown in Table 1 as the “falling amount of water droplet” of the coating. The cured product of the silicone resin for film formation showed good water repellency with a water drop amount of 1 μL or less.

(Example 2) The same reactor as in Example 1
Under the conditions, 26.25 g of polydimethylsiloxane having hydroxyl groups at both terminals and having an average degree of polymerization of 23 was reacted to obtain a silicone resin as a wax-like solid. The weight average molecular weight in terms of polystyrene of the obtained silicone resin was 3,100, and the number average molecular weight was 630. (A + b) determined from the ²⁹ Si NMR spectrum
The value of / (c + d) is 0.43, (a + c) / (a + b +
The value of c + d) was 0.226.

This silicone resin was cured in the same manner as in Example 1. Table 1 shows the results of the water repellency test performed in the same manner as in Example 1.

(Example 3) The same reaction apparatus as in Example 1
Under the conditions, the reaction was carried out using 26.25 g of polydimethylsiloxane having an average degree of polymerization of 240 having hydroxyl groups at both ends,
The silicone resin was obtained as a waxy solid. The weight average molecular weight of the obtained silicone resin in terms of polystyrene was 9,100, and the number average molecular weight was 720. (A + b) determined from the ²⁹ Si NMR spectrum
The value of / (c + d) is 0.42, (a + c) / (a + b +
The value of c + d) was 0.198.

This silicone resin was cured in the same manner as in Example 1. Table 1 shows the results of the water repellency test performed in the same manner as in Example 1. The cured product of the silicone resin for forming a coating film showed good water repellency with a water drop amount of 1 μL or less.

(Example 4) The same reaction apparatus as in Example 1
Under the conditions, 49.66 g of polydimethylsiloxane having an average polymerization degree of 55 having hydroxyl groups at both ends was reacted with 100.34 g (0.692 mol) of methyltrichlorosilane to obtain a silicone resin as a waxy solid. . The weight average molecular weight of the obtained silicone resin in terms of polystyrene was 4,200, and the number average molecular weight was 91.
It was 0. The value of (a + b) / (c + d) determined from the ²⁹ Si NMR spectrum was 0.98, (a + c) /
The value of (a + b + c + d) was 0.205.

This silicone resin was cured in the same manner as in Example 1. Table 1 shows the results of the water repellency test performed in the same manner as in Example 1. The cured product of the silicone resin for forming a coating film showed good water repellency with a water drop amount of 1 μL or less.

(Example 5) The same reaction apparatus as in Example 1
Under the conditions, water 400mL and methyl isobutyl ketone 300mL
Was added, and vigorously stirred so as not to form two layers, 16.77 g of polydimethylsiloxane having an average polymerization degree of 55 having hydroxyl groups at both terminals was added, further stirred, and placed in an ice bath. When the temperature of the mixture in the reaction vessel reached 10 ° C., 118.61 g of methyltrichlorosilane (0.
793 mol) and 14.62 g of dimethyldichlorosilane
(0.133 mol) in 100 mL of methyl isobutyl ketone was slowly dropped from a dropping funnel.
Thereafter, the same treatment as in Example 1 was performed to obtain a silicone resin as a wax-like solid. The weight average molecular weight of the obtained silicone resin in terms of polystyrene was 485.
It was 0 and the number average molecular weight was 910. ²⁹ Si
The value of (a + b) / (c + d) determined from the NMR spectrum was 0.42, and the value of (a + c) / (a + b + c + d) was 0.202.

This silicone resin was cured in the same manner as in Example 1. Table 1 shows the results of the water repellency test performed in the same manner as in Example 1. The cured product of the silicone resin for forming a coating film showed good water repellency with a water drop amount of 1 μL or less.

(Example 6) The same reaction apparatus as in Example 1
Under the conditions, water 400mL and methyl isobutyl ketone 250mL
Was added and stirred vigorously so as not to form two layers, and placed in an ice bath. When the temperature of the mixture in the reaction vessel reached 10 ° C., 82.60 g of phenyltrichlorosilane (0.
390 mol) in 100 mL of methyl isobutyl ketone was slowly dropped from a dropping funnel. At this time, the temperature of the reaction mixture rose to 15 ° C. After dropping,
The reaction mixture was heated and stirred on a 60 ° C. oil bath for 1 hour.
Thereafter, a solution in which 67.40 g of polydimethylsiloxane having hydroxyl groups at both terminals and having an average degree of polymerization of 55 and 50 mL of methyl isobutyl ketone was dissolved was slowly dropped from the dropping funnel again. After completion of the dropwise addition, the reaction mixture was again heated and stirred on a 60 ° C. oil bath for 1 hour. The same treatment as in Example 1 was performed to obtain a silicone resin as a waxy solid. The weight average molecular weight of the obtained silicone resin in terms of polystyrene was 5100, and the number average molecular weight was 10
00. The value of (a + b) / (c + d) determined from the ²⁹ Si NMR spectrum was 2.47, (a + c) /
The value of (a + b + c + d) was 0.202.

This silicone resin was cured in the same manner as in Example 1. Table 1 shows the results of the water repellency test performed in the same manner as in Example 1. The cured product of the silicone resin for forming a coating film showed good water repellency with a water drop amount of 1 μL or less.

(Example 7) The same reaction apparatus as in Example 1
Under the conditions, 400 mL of water, 175 mL of toluene and 75 mL of isopropanol were added, and the mixture was stirred vigorously so as not to form two layers, and placed in an ice bath. When the temperature of the mixture in the reaction vessel is 10
℃, phenyltrichlorosilane
A solution of 60 g (0.390 mol) dissolved in 100 mL of toluene was slowly dropped from a dropping funnel. At this time, the temperature of the reaction mixture rose to 15 ° C. After the completion of the dropwise addition, the reaction mixture was heated on an oil bath and stirred for 6 hours under azeotropy.
Thereafter, a solution of 67.40 g of polydimethylsiloxane having hydroxyl groups at both ends and having an average degree of polymerization of 55 in 50 mL of toluene was slowly dropped again from the dropping funnel.
After completion of the dropwise addition, the reaction mixture was stirred again for 6 hours under azeotropy. The same treatment as in Example 1 was performed to obtain a silicone resin as a solid. The weight average molecular weight of the obtained silicone resin in terms of polystyrene was 3656200,
The number average molecular weight was 989250. Also ²⁹ SiNM
The value of (a + b) / (c + d) determined from the R spectrum was 2.15, and the value of (a + c) / (a + b + c + d) was 0.1.
072.

This silicone resin was cured in the same manner as in Example 1. Table 1 shows the results of the water repellency test performed in the same manner as in Example 1. The cured product of the silicone resin for forming a coating film showed good water repellency with a water drop amount of 1 μL or less.

(Comparative Example 1) The same reactor as in Example 1
Under the conditions, water 400mL and methyl isobutyl ketone 300mL
Was added and stirred vigorously so as not to form two layers, and placed in an ice bath. When the temperature of the mixture in the reaction vessel reached 10 ° C., 130.14 g of methyltrichlorosilane (0.1.
871 mol) and 19.86 g of dimethyldichlorosilane
(0.154 mol) in 100 mL of methyl isobutyl ketone was slowly dropped from a dropping funnel.
Thereafter, the same treatment as in Example 1 was performed to obtain a silicone resin as a flake-like solid. The weight average molecular weight of the obtained silicone resin in terms of polystyrene is 190.
It was 0 and the number average molecular weight was 560. ²⁹ Si
The value of (a + b) / (c + d) determined from the NMR spectrum was 0.19, and the value of (a + c) / (a + b + c + d) was 0.206.

This silicone resin was cured in the same manner as in Example 1. Table 1 shows the results of the water repellency test performed in the same manner as in Example 1. The cured product of the silicone resin for forming a coating film showed a water drop amount of 4 μL.

[Table 1] Amount of water droplet falling on cured silicone resin coating Example No. Amount of water droplet falling (μL) ───────────────────── Example 10 8 Example 2 1.0 Example 3 0.8 Example 4 0.8 Example 5 1.0 Example 6 0.8 Example 7 0.8 Comparative Example 1 4.0 ──────────────

[0057]

The present invention provides a silicone resin having a specific structure capable of forming a coating exhibiting excellent water repellency even when used alone without blending other components. is there.

Claims (4)

[Claims] The average structure is represented by the general formula [R¹ _TwoR^TwoSiO_1/2]_a[R¹ _TwoSiO_2/2]_b[R^Two
R^ThreeSiO_2/2]_c[R ^ThreeSiO_3/2]_d [Where R¹Are each independently an alkyl having 1 to 5 carbon atoms
R group, R^TwoAre each independently a hydroxyl group or a group having 1 to 5 carbon atoms.
An alkoxy group of R^ThreeEach independently has 1 to 5 carbon atoms
An alkyl group or an aromatic hydrocarbon group, a, b, c
And d satisfy the following conditions. 1) a + b + c + d = 1 (where a is 0 or a positive number)
Where b, c, and d are positive numbers. 2) 0.25 ≦ (a + b) / (c + d) ≦ 4.0 3) 0.05 ≦ (a + c) / (a + b + c + d) ≦ 0.
40] a silicone resin for forming a water-repellent film. 2. The silicone resin for forming a water-repellent film according to claim 1, which has the following characteristics: at least a polydimethylsiloxane unit having an average degree of polymerization of 5-1.
000. In one molecule, the ratio of the number of units of the following (1) to the number of units of the following (2) is 1 or more (however, this does not apply when the unit of the following (2) does not exist). (1) Polydimethylsiloxane unit of [(CH ₃ ) ₂ SiO _2/2 ] _m (m ≧ 2) (2) Dimethyl siloxane unit of [(CH ₃ ) ₂ SiO _2/2 ] _m (m = 1) ( 0.3 ≦ (a + b) / (c + d) ≦ 3. 3. The method according to claim 1, which is produced by performing hydrolysis and condensation of the following (A) and (B) in a two-phase reaction system comprising the following (a) and (b). Silicone resin for forming water-repellent coating. (A) the following or: an oxygen-containing organic solvent; a mixed solvent comprising an oxygen-containing organic solvent and a hydrocarbon solvent (however, the proportion of the hydrocarbon solvent contained in the mixed solvent is 50% by volume or less); (b) 1.8 g or less of a water-soluble inorganic base or water containing or not containing a salt of a weak acid having a buffering capacity per mole of a halogen atom in the following (A) and (B); ³ Six ₃ (R ³ has the same meaning as above,
X is a halogen atom. Organotrihalosilane represented by); (B) formula _{^{Y (SiR 1 2 O) e}} SiR 1 2 Y (Y is a halogen atom, hydroxyl group, at least one selected from hydrogen, e is positive for 0 or 300 or less And R ¹ has the same meaning as described above.) Or a diorganopolysiloxane having a functional group at both terminals. 4. A silicone resin composition for forming a water-repellent film, comprising 100 parts by weight of the silicone resin according to claim 1, 2 or 3, and 0.01 to 10 parts by weight of a curing catalyst.