JP2002114941A - Curable resin composition for water repellent paint and coated material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable resin composition for a water repellent paint showing excellent water repellency, and retaining its function, and to provide a coated material comprising coating the resin composition. SOLUTION: The curable resin composition for the water repellent paint comprises (A) a hydroxyl group-containing silicone acrylic block polymer which is obtained by polymerizing (a1) an acrylic monomer having a hydroxyl group or (a2) a mixture of (a1) the acrylic monomer with another ethylenically unsaturated monomer in the presence of an azo group-containing silicone macroinitiator, (B) a polyisocyanate curing agent and/or a melamine curing agent, and (C) an inorganic particle which is an aggregate of a primary particle having an average particle diameter of several 10 nm and which has an average particle diameter of 1-10 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a curable resin composition for a water-repellent paint, and a coated product obtained by applying the same.

[0002]

2. Description of the Related Art In order to prevent accidents and obstacles due to icing and snow, structures such as power transmission lines and steel towers laid in snowfall areas are
Surface treatment with a substance having water repellency has been performed. In addition, a heat exchanger for an outdoor unit of an air heat source type heat pump air conditioner is also subjected to the same surface treatment in order to prevent frost which is a cause of a decrease in cooling / heating capacity.

[0003] JP-A-2000-212474 discloses that
A curable resin composition for a water-repellent paint, comprising a silicone acrylic block polymer obtained by using a silicone macroinitiator, a curing agent, and a powder of an inorganic oxide subjected to a hydrophobic treatment is disclosed. However, although this resin composition has water repellency, there is a problem that the water repellency cannot be maintained for a long period of time.

[0004]

DISCLOSURE OF THE INVENTION In view of the above situation, the present invention provides a curable resin composition for water-repellent paint which exhibits excellent water repellency and maintains its function, and a coated article coated with the same. It is intended to provide.

[0005]

According to the present invention, there is provided an acrylic monomer (a1) having a hydroxyl group or the above acrylic monomer (a1) in the presence of an azo group-containing silicone macroinitiator.
And a hydroxyl group-containing silicone acryl block polymer (A) obtained by polymerizing a mixture of the above and another ethylenically unsaturated monomer (a2), a polyisocyanate curing agent and / or a melamine curing agent (B), and an average Particle size is several tens nm
And a curable resin composition for a water-repellent coating, comprising inorganic particles (C) having an average particle diameter of 1 to 10 μm.

Hereinafter, the present invention will be described in detail. The curable resin composition for a water-repellent paint of the present invention comprises a hydroxyl-containing silicone acrylic block polymer (A), a polyisocyanate curing agent and / or a melamine curing agent (B), and 1 to 10 μm.
It is composed of inorganic particles (C) having an average particle diameter of m.

The above-mentioned hydroxyl group-containing silicone acrylic block polymer (A) is prepared by preparing an acrylic monomer having a hydroxyl group (a1) or the above-mentioned acrylic monomer (a1) in the presence of an azo group-containing silicone macroinitiator. Obtained by polymerizing a mixture of the ethylenically unsaturated monomers (a2).

The azo group-containing silicone macroinitiator includes, for example, the following compounds described in JP-B-2-33053 and JP-A-7-18139.

[0009]

Embedded image

Wherein R ₁ is the same or different and represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a nitrile group. R ₂ is the same or different and represents a hydrogen atom or a 1 to 6 carbon atom. R ₃ is the same or different and represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or a phenyl group, and p and q are the same or different and represent an integer of 0 to 6 And m represents an integer of 0 to 200.) An azo group-containing polysiloxane amide comprising a repeating unit represented by the following formula: Among these, the number average molecular weight of the silicone chain portion is 2,000 to 2,000.
30,000 is preferred.

The azo group-containing silicone macroinitiator can be synthesized, for example, by reacting a diamine having a polysiloxane segment with an azo group-containing dibasic acid dihalide.

As the azo group-containing silicone macroinitiator, those obtained by bonding 4,4'-azobis (4-cyanovaleric acid) to a polydimethylsiloxane chain via an amide bond are commercially available from Wako Pure Chemical Industries as VPS series. It is possible to use this.

The acrylic monomer (a1) which is a monomer component of the hydroxyl-containing silicone acrylic block polymer (A) has a hydroxyl group. When only a monomer having no reactive functional group such as vinyl chloride, styrene or methyl methacrylate is used as a monomer component of the hydroxyl group-containing silicone acrylic block polymer (A), the water repellency of the resulting coating film is obtained. In the present invention, an acrylic monomer (a1) having a hydroxyl group is used.

The acrylic monomer having a hydroxyl group (a)
As 1), for example, 2-hydroxyethyl (meth)
Acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-
Adducts of hydroxyethyl (meth) acrylate and ε-caprolactone (Placcel FM series or Placcel FA series) and the like can be mentioned. The acrylic monomers (a1) can be used alone or in combination of two or more.

The monomer component of the hydroxyl group-containing silicone acrylic block polymer (A) includes, in addition to the acrylic monomer (a1), other ethylenically unsaturated monomers (a).
2) may be included. The other ethylenically unsaturated monomer (a2) is not particularly limited.
Aromatic monomers such as styrene, p-methylstyrene, and t-butylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, n-butyl (meth) acrylate, and t-butyl (meth) A) acrylates such as acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and cyclohexyl (meth) acrylate; fluoroalkyls such as perfluoroethylmethyl (meth) acrylate Meth) acrylate; acrylamide, dimethyl (meth) acrylamide, (meth) acrylonitrile,
Other monomers such as vinyl acetate can be exemplified.

The other ethylenically unsaturated monomer (a2)
Glycidyl (meth) acrylate, α
-Methyl glycidyl (meth) acrylate, methacrylic acid ester having an alicyclic epoxy group (cyclomer
M-100: manufactured by Daicel Chemical Industries, Ltd.); carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid and anhydrides and half esters thereof; Active methylene group-containing monomers such as acetoxyethyl (meth) acrylate and 2-ethoxymalonyloxyethyl (meth) acrylate; alkoxysilyl groups such as 3-methacryloyloxypropyltrimethoxysilane and 3-methacryloyloxypropyldimethoxymethylsilane A monomer having a crosslinkable functional group other than the above-mentioned hydroxyl group such as a contained monomer can be exemplified. The other ethylenically unsaturated monomers (a2) can be used alone or in combination of two or more.

The other ethylenically unsaturated monomer (a2)
Among them, as the compounding amount of the monomer having a crosslinkable functional group other than the above-mentioned hydroxyl group, it is preferable to add an amount that does not inhibit the stability of the coating composition. The hydroxyl value of the obtained hydroxyl-containing silicone acrylic block polymer (A) is 30 to 120, preferably 50 to 1.
It is preferable that the acrylic monomer (a1) having a hydroxyl group and the other ethylenically unsaturated monomer (a2) are blended so as to be 00. Further, the acrylic monomer (a1) having a hydroxyl group and the other ethylenically unsaturated monomer (a2) have a calculated glass transition temperature Tg of the obtained hydroxyl group-containing silicone acrylic block polymer (A) of 20.
It is preferable to mix so that the temperature may be up to 50C.

The method for producing the hydroxyl group-containing silicone acrylic block polymer (A) is as follows. In the presence of the azo group-containing silicone macroinitiator, the hydroxyl group-containing acrylic monomer (a1) or the hydroxyl group-containing silicone monomer is used. A mixture of the acrylic monomer (a1) and the other ethylenically unsaturated monomer (a2) can be obtained by polymerization by a conventional bulk polymerization method or a solution polymerization method.

The above monomer component, that is, an acrylic monomer (a1) or a mixture of the acrylic monomer (a1) and another ethylenically unsaturated monomer (a2), and the silicone macroinitiator Is preferably in the range of 95: 5 to 50:50 in terms of weight ratio when the total of both is 100 parts by weight. Outside these ranges, the hydroxyl group-containing silicone acrylic block polymer (A) may not have good water repellency and may have poor compatibility with other components. More preferably, it is 90:10 to 65:35.

In the case where the above polymerization method is a solution polymerization method, the solvent is not particularly limited, and for example, tetrahydrofuran,
Ethers such as dioxane; hydrocarbon solvents such as petroleum ether, n-hexane, cyclohexane, toluene and xylene; esters such as ethyl acetate and butyl acetate; alcohols such as methanol, ethanol, isopropanol and butanol; acetone and methyl ethyl ketone , Methyl isobutyl ketone, ketones such as cyclohexanone;
Acetonitrile, N, N-dimethylformamide, dimethylsulfoxide and the like can be mentioned. The above solvents can be used alone or as a mixture. In the above polymerization, if necessary, the molecular weight can be adjusted by using a chain transfer agent such as n-dodecyl mercaptan.
When the residual unreacted monomer component is not desirable, an initiator such as an azo initiator may be further added during the reaction to complete the polymerization.

In the present invention, the azo group-containing silicone macroinitiator generates nitrogen (N ₂ ) by heating or light irradiation and decomposes to generate radical species, whereby the acrylic monomer (a1) or the acrylic monomer Monomer (a
A mixture of 1) and another ethylenically unsaturated monomer (a2) undergoes polymerization while at the same time radical fragments having a polysiloxane segment formed from a silicone macroinitiator are introduced into the acrylic polymer to form a polysiloxane. Segment (A1) and acrylic polymer segment (A2)
[(A1) (A2)] type or [(A1) (A
2) (A1)] type hydroxyl-containing silicone acrylic block polymer (A) can be produced.

The hydroxyl group-containing silicone acrylic block polymer (A) contains one to two acrylic polymer blocks in the chain, and the number average molecular weight is usually on the order of tens of thousands.

The curable resin composition for a water-repellent paint of the present invention contains a polyisocyanate curing agent and / or a melamine curing agent (B) in addition to the above-mentioned hydroxyl group-containing silicone acrylic block polymer (A). The curing agent (B) reacts with a hydroxyl group of the hydroxyl group-containing silicone acrylic block polymer (A),
For example, a melamine resin (Cymel-211), a block isocyanate (MEK oxime block HMDI nullate), a polyisocyanate crosslinking agent (IPDI nullate; Takenate D-140N, HMDI nullate; Coronate HX, MDI; Coronate 2041) and the like can be mentioned. Can be. The polyisocyanate curing agent may be a block in which isocyanate groups are blocked by a blocking agent.

The curable resin composition for a water-repellent coating of the present invention is an aggregate of primary particles having an average particle size of several tens nm, and contains an inorganic particle (C) having an average particle size of 1 to 10 μm. It is a thing.

The inorganic particles (C) having an average particle diameter of 1 to 10 μm are present as particulate matter in the coating film after the formation of the coating film. By mixing the inorganic particles (C) having an average particle diameter of 1 to 10 μm, fine irregularities are imparted to the surface after curing of the coating film, the apparent contact angle to water increases, and higher water repellency is obtained. The water repellency can be maintained for a long time.

The inorganic particles (C) having an average particle size of 1 to 10 μm are aggregates of primary particles. The preferred average particle size is 1 to 5 μm. If it is less than 1 μm, sufficient water repellency cannot be obtained, and if it exceeds 10 μm, the resulting coating film may have excessively large unevenness and may have low water repellency. The average particle size can be determined by a well-known method such as a Coulter counter. Although the particle diameter of the primary particles is several tens nm, in this specification, several tens nm means a range of 10 nm or more and less than 100 nm.

Since the inorganic particles (C) having an average particle size of 1 to 10 μm are aggregates of primary particles, they have a larger BET specific surface area and a smaller bulk specific gravity than primary particles having the same average particle size. . BET specific surface area is 50-100m
² / g and a bulk specific gravity of 10 to 120 g / l are preferable. Outside of these ranges,
There is a possibility that sufficient water repellency cannot be obtained.

The inorganic particles (C) having an average particle diameter of 1 to 10 μm are preferably hydrophobic silica from the viewpoint of availability. This hydrophobic silica is obtained by subjecting silica having an average particle size of several μm to silica of several tens of nm under basic conditions, and then subjecting the silica to secondary aggregation under acidic conditions and subjecting it to a hydrophobic treatment. It is. As the above-mentioned hydrophobization treatment, a method of performing treatment so as to have a hydrophobic group such as a lower alkyl group such as a methyl group or an ethyl group or a fluorinated alkyl group on the powder surface of the inorganic oxide, or a silicone oil A surface treatment method by vapor-phase adsorption can be used.

As the above-mentioned hydrophobic silica having an average particle diameter of 1 to 10 μm, silica which has been treated by adsorbing silicone oil in the gas phase is preferable, and commercially available products include Nipsil SS series manufactured by Nippon Silica Co., Ltd. Can be mentioned.

The curable resin composition for a water-repellent paint of the present invention comprises the above-mentioned hydroxyl group-containing silicone acrylic block polymer (A), the above-mentioned curing agent (B) and the above-mentioned inorganic particles (C) having an average particle diameter of 1 to 10 μm. ).

The amount of the curing agent (B) is, for example, from 5 to 1 in terms of solid content based on 100 parts by weight of the solid content of the hydroxyl group-containing silicone acrylic block polymer (A).
00 parts by weight and the like. If the amount is less than 5 parts by weight, the crosslinking may be insufficient. If the amount exceeds 100 parts by weight, the water repellency of the resulting coating film may decrease due to a decrease in the amount of the hydroxyl group-containing silicone acrylic block polymer (A).

The amount of the inorganic particles (C) having an average particle diameter of 1 to 10 μm is preferably 20 to 60% by weight based on the total weight of the solid content of the curable resin composition for water-repellent paint. When the content is less than 20% by weight, the apparent water contact angle of the obtained coating film is not increased and the water repellency is poor.
The effect of adding the inorganic particles (C) having an average particle size of μm cannot be expected. Even if it exceeds 60% by weight,
Not only does the water repellency of the obtained coating film not change, but also mechanical properties such as coating film adhesion may be poor. More preferably, it is 30 to 55% by weight. Further, in order to adjust the surface roughness of the obtained coating film, in addition to the inorganic particles (C) having an average particle diameter of 1 to 10 μm, silica or titania having a particle diameter of 40 nm or less and subjected to hydrophobic treatment is used. Primary particles can be used in combination. When the primary particles are silica, the aggregates become inorganic particles (C) having an average particle diameter of 1 to 10 μm. When the primary particles are used in combination, the amount is preferably not more than the inorganic particles (C) having an average particle diameter of 1 to 10 μm.

The curable resin composition for a water-repellent coating of the present invention may further contain an acrylic polyol (D). By further adding the acrylic polyol (D), mechanical properties such as hardness and coating film adhesion of the obtained coating film can be improved.

The acrylic polyol (D) preferably has a number average molecular weight of 2,000 to 7000. The acrylic polyol (D) is obtained by polymerizing the same acrylic monomer (a1) having a hydroxyl group and the other ethylenically unsaturated monomer (a2) according to a conventional method. Obtainable. The acrylic polyol having the above number average molecular weight is used in an amount of a polymerization initiator higher than usual, for example, 5 to 20% by weight based on the monomer component, or a polymerization temperature higher than usual.
For example, it can be obtained by carrying out polymerization at 150 to 180 ° C. and / or blending a chain transfer agent to carry out polymerization.

The amount of the acrylic polyol (D) is 15 parts by weight based on 100 parts by weight of the solid content of the hydroxyl-containing silicone acrylic block polymer (A).
It is preferably 0 parts by weight or less. If it exceeds 150 parts by weight, excellent water repellency may not be exhibited.

The curable resin composition for a water-repellent coating of the present invention may further contain a silicone oil (E).
By further adding the silicone oil (E), the water repellency can be maintained for a long time.

As such a silicone oil (E), a conventional oil such as liquid polydimethylsiloxane or a reactive silicone having a reactive functional group such as a hydroxyl group, an amino group or an epoxy group can be used. The silicone oil (E) preferably has a smaller number average molecular weight than the silicone chain portion of the hydroxyl group-containing silicone acrylic polymer (A), and the lower limit is preferably about 1500. If it is less than 1500, bleeding occurs. The amount of the silicone oil (E) to be added is as follows: the hydroxyl group-containing silicone acrylic block polymer (A)
The solid content is preferably 1 to 50 parts by weight based on 100 parts by weight of the solid content. If the amount is less than 1 part by weight, no effect can be obtained, and if it exceeds 50 parts by weight, the effect corresponding thereto cannot be obtained and it is not efficient.

The curable resin composition for a water-repellent coating of the present invention can contain additives such as an anti-sagging agent; a leveling agent; an ultraviolet absorber; and an antioxidant. Normal coloring pigments; may also include extender pigments. Transmission line of the curable resin composition for a water-repellent coating of the present invention,
When applied to a structure such as a steel tower, the curable resin composition for a water-repellent coating does not need to be visible, and the effect of absorbing heat by sunlight to melt ice and snow and evaporate is synergistically obtained. From the viewpoint that it is possible, it is preferable to blend a color pigment such as a black pigment. From the viewpoint that more effects can be obtained, it is more preferable to adopt a compound other than the composition consisting of only the white pigment. Further, in the case of a urethane curing system, a tin catalyst such as dibutyltin dilaurate; in the case of a melamine curing system, a sulfonic acid catalyst such as dotesylbenzenesulfonic acid blocked with an amine may be included.

The method for preparing the curable resin composition for a water-repellent paint of the present invention can be carried out by mixing and stirring the respective components, and can be used for bases such as metals, plastics, glass and woody materials which require water repellency. The material can be coated on the surface by a conventional coating method such as spray coating, brush coating, roller coating and the like.

The curable resin composition for a water-repellent paint of the present invention is applied so that the dry film thickness is usually 10 to 100 μm. The method for curing the coating film is a conventionally known method, for example, 110 to 180 C. and baking for 5 to 80 minutes.

A coated product obtained by applying the curable resin composition for a water-repellent coating of the present invention is also one of the present invention. In the coated product of the present invention, the apparent water contact angle is 100 to
A coating exhibiting 170 °, preferably 145-160 °, is obtained.

The curable resin composition for a water-repellent coating of the present invention is one in which the above-mentioned hydroxyl-containing silicone acrylic block polymer (A) itself has good water repellency.
Since the hydroxyl group-containing silicone acrylic block polymer (A) is crosslinked by the curing agent (B), the water repellency of the coating film does not decrease over time. In addition, the above 1 to
Since the inorganic particles (C) having an average particle diameter of 10 μm are added, the apparent water contact angle of the resulting coating film can be greatly increased, and excellent water repellency can be exhibited.

Further, the curable resin composition for a water-repellent paint of the present invention can maintain water repellency for a long period of time by further containing a silicone oil (E). This means that in the coating film obtained from the curable resin composition for a water-repellent paint of the present invention, the silicone oil (E) is contained inside the inorganic particles (C) having an average particle size of 1 to 10 μm.
This is considered to prevent water from entering the inside, which causes the water repellency to decrease due to the penetration by capillary action.

The substrate to which the curable resin composition for a water-repellent paint of the present invention is applied is not particularly limited, but articles requiring water repellency, such as automobile bodies, building exteriors and rooftops, Examples thereof include outdoor structures such as electric wires and steel towers, and fins of a heat exchanger for an outdoor unit for an air heat source type heat pump air conditioner. The curable resin composition for a water-repellent coating of the present invention has an extremely excellent effect, and among the above-mentioned objects to be coated, particularly, a power transmission line and a steel tower for laying in a snowfall area, and an air heat source type heat pump air conditioner. The fins of the outdoor unit heat exchanger are preferred.

When the curable resin composition for a water-repellent paint of the present invention is applied to a transmission line for a snowfall zone, it hardly adheres to ice and snow. The product is a hard-to-ice and snow coating composition, and when the curable resin composition for a water-repellent coating of the present invention is applied to a fin of a heat exchanger, the coating composition is a frost prevention coating composition. In particular, application as a hard-to-ice and snow coating composition is one of the most suitable application examples of the curable resin composition for a water-repellent coating of the present invention.

[0046]

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

Synthesis Example 1 Preparation of Hydroxyl-Containing Silicone Acrylic Block Polymer (A) Part 1 In a 500 mL glass container equipped with a stirring blade, a nitrogen inlet tube, a cooling condenser and a dropping funnel, butyl acetate 5 was added.
1.5 g and 116.5 g of methoxypropyl acetate were added, and the mixture was heated to 120 ° C. under a nitrogen atmosphere. In that container,
20 g of VPS-1001 (azo group-containing silicone amide; Wako Pure Chemical Industries, Ltd.) dissolved in 60 g of butyl acetate, 47.9 g of cyclohexyl methacrylate, Plaxel FM
-2D (1: 2 adduct of 2-hydroxyethyl methacrylate and ε-caprolactone; manufactured by Daicel Industries) 2
3.0 g, 2-hydroxyethyl methacrylate 9.0
g was dripped at a constant velocity over 3 hours. Thereafter, the temperature was maintained at 120 ° C. for 0.5 hour, and 0.2 g of azobisisobutyronitrile dissolved in 5 g of butyl acetate was dropped at a constant speed in 30 minutes. Further, by continuing heating at 120 ° C. for 1.5 hours, a target block copolymer was obtained. The azo group-containing silicone amide (VPS-1001) has the following structure.

[0048]

Embedded image

For the synthesized block copolymer, GP
The value of the molecular weight in terms of standard polystyrene obtained using C was Mn = 9300, Mw = 96700, and Mw / Mn = 1.
0.44. The hydroxyl value is 75.0 mg KO.
H / g and resin solids were 27%.

Synthesis Example 2 Preparation of Hydroxyl Group-Containing Acrylic Silicone Block Polymer Part 2
0 g was added, and the mixture was heated to 120 ° C. under a nitrogen atmosphere. 20 g of an azo group-containing silicone amide (VPS-0501; manufactured by Wako Pure Chemical Industries) dissolved in 60 g of butyl acetate,
9.1 g of n-butyl methacrylate, 56.0 g of ethyl methacrylate and 14.9 g of 2-hydroxyethyl methacrylate were dropped at a constant rate over 3 hours. Then 1
The solution was kept at 20 ° C. for 0.5 hour, and 0.2 g of azobisisobutyronitrile dissolved in 5 g of butyl acetate was dropped at a constant speed in 30 minutes. Further, by continuing heating at 120 ° C. for 1.5 hours, a target block copolymer was obtained. The azo group-containing silicone amide (VPS-0501) has the following structure.

[0051]

Embedded image

For the synthesized block copolymer, GP
The value of the molecular weight in terms of standard polystyrene obtained using C is Mn = 15500, Mw = 62800, Mw / Mn =
4.04. The hydroxyl value is 64.0 mg KO.
H / g, resin solid content was 37%.

Synthesis Example 3 Production of Acrylic Polyol 5 butyl acetate was placed in a 500 mL glass container equipped with a stirring blade, a nitrogen inlet tube, a cooling condenser, and a dropping funnel.
6.4 g and 119.6 g of methoxypropyl acetate were added, and the mixture was heated to 120 ° C. under a nitrogen atmosphere. In that container,
51.8 g of butyl acetate, tert-butyl peroxy 2
-Ethylhexanoate 11.5 g, cyclohexyl methacrylate 137.8 g, Plaxel FM-2D (2
66.2 g of 2-hydroxyethyl methacrylate and 2: 6.0 g of 2-hydroxyethyl methacrylate) were added dropwise over 3 hours. After that, it is kept at 120 ° C for 0.5 hour,
1.2 g of tert-butyl peroxy 2-ethylhexanoate dissolved in 11.5 g of butyl acetate was added dropwise at a constant speed in 30 minutes. Furthermore, the target acrylic polyol was obtained by continuing heating at 120 degreeC for 1.0 hour. For the synthesized acrylic polyol, the value of the molecular weight in terms of standard polystyrene obtained using GPC was Mn = 42.
00, Mw = 9000, Mw / Mn = 2.14. The hydroxyl value was 93.8 mg KOH / g, and the calculated T
g was 31.2 ° C. and the resin solids was 48.8%.

Examples 1-4, Comparative Example 1 Resin solutions of Synthesis Examples 1, 2 and 3, Coronate HX (curing agent; HMDI-Nurate; manufactured by Nippon Polyurethane Industry) /
Butyl acetate solution (solid content 50%), SS178B (average particle diameter 2.9 μm, average primary particle diameter 24 nm, B
Hydrophobic silica having an ET specific surface area of 69 m ² / g and a bulk density of 104 g / l; manufactured by Nippon Silica Co., Ltd., silicone oil KF-96 100cs (manufactured by Shin-Etsu Chemical Co., Ltd., Mn = 6)
000), dibutyltin dilaurate, tinuvin 328
(Ultraviolet absorber; manufactured by Nippon Ciba Geigy), Sanol L
S292 (Antioxidant; manufactured by Sankyo) and ethyl acetate were mixed and stirred in the amounts shown in Table 1 to prepare a coating composition. Apply it on an aluminum plate using an applicator,
Baking was performed at 0 ° C. for 60 minutes to obtain a coating film having a thickness of 30 μm.
In Table 1, PWC (%) is the weight percentage of the inorganic particles (C) in the total solid content of the coating composition.

[0055]

[Table 1]

Comparative Example 2 20.0 parts by weight of the resin solution of Synthesis Example 1 was mixed with a melamine resin (hard
Agent: Cymel-211, solid content 80%; Mitsui Toatsu Chemical
4.0 parts by weight, iso-dodecylbenzenesulfonic acid
Propanol solution (Nacure 5225; active 25
%; Manufactured by Kusumoto Chemicals) 0.042 parts by weight, Aerosil
 R-202 (surface treated with dimethyl silicone oil
Silica: average primary particle diameter of about 14 nm, BET specific surface
Product 100m ²/ G; Nippon Aerosil Co., Ltd.) 4.56 weight
Parts and 47 parts by weight of ethyl acetate are mixed and stirred to obtain a coating composition.
Was prepared. Inorganic particles in the total solid content of this coating composition
The weight percentage PWC occupied was 30%. This paint group
Apply the product on an aluminum plate using an applicator,
Baking at 40 ° C for 20 minutes to obtain a coating with a thickness of about 40μm
Was.

<Evaluation of water repellency of coating film> The water repellency of the coating films obtained in Examples and Comparative Examples was evaluated by measuring a water contact angle and a water falling angle. The water contact angle of the coating film was measured using an automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., CA
-Z), a droplet having a diameter of about 3 mm was formed, and the water contact angle was obtained after 30 seconds. On the other hand, the water falling angle of the coating film was measured using a contact angle meter (Kyowa Interface Chemical Co., Ltd., CA-C).
It was determined as the angle of inclination of the test plate when 30 μL of water droplets began to slide. Table 2 shows the results. The water contact angle is 14
0 ° or more is acceptable, and the water falling angle is 15 ° or less. In addition, the evaluation of water repellency over a long period
After immersion in hot water at 0 ° C., the air layer formed at the interface was forcibly removed by water pressure, and after 1 hour, the test plate was taken out.
After air drying for 0 minutes, the measurement was performed by measuring the water contact angle and the water falling angle. The results are summarized in Table 2.

[0058]

[Table 2]

As compared with Comparative Example 1 in which no hydrophobic silica was added, in the example, both the water contact angle and the water falling angle showed values indicating water repellency. Also. In Comparative Example 2 in which primary particles of silica not forming an aggregate were added, although the initial water repellency was good, the values of the water contact angle and the water falling angle after immersion in warm water for 1 hour had already been greatly reduced. . With such a result, water repellency cannot be maintained for a long time. On the other hand, in Examples 1 to 4, reductions in the values of the water contact angle and the water falling angle after immersion in warm water for 1 hour are small,
It was found that the water repellency could be maintained for a long time. Further, as a more severe condition, the above-mentioned evaluation of water repellency was carried out at an immersion time of 3 hours. In the system to which the silicone oil of Example 2 was added, the water contact angle was 152 °,
The water contact angle was 1 °, but the water contact angle was in the acceptable range, but the water falling angle was 90 ° or more. From this, it seems that the water repellency can be maintained particularly for a long time in the system to which the silicone oil is added.

[0060]

Since the curable resin composition for a water-repellent coating of the present invention has the above-mentioned constitution, the resulting coating film can exhibit excellent water-repellency and maintain its water-repellent function. . When the silicone oil (E) is contained, the effect is particularly remarkable. For this reason, it is applied to power transmission lines for snowfall areas,
It can be applied to fins of a heat exchanger to obtain a frost preventing paint composition.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masatoshi Ohata 19-17 Ikedanakacho, Neyagawa-shi, Osaka Inside Nippon Paint Co., Ltd. Co., Ltd. (72) Inventor Kiyotada Yasuhara 4-1-1, Minamishinagawa, Shinagawa-ku, Tokyo Japan Paint Co., Ltd. (72) Inventor Yutaka Matsuzaki 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. In-house (72) Inventor Hideo Banse 2-6-1 Marunouchi, Chiyoda-ku, Tokyo F-kawa Electric Industry Co., Ltd. F-term (reference) 4J038 CC061 CC062 CF071 CF072 CG031 CG032 CG141 CG142 CG151 CG152 CG161 CG162 CG171 CG172 CH031 CH032 CH041 CH042 CH121 CH122 CH171 CH172 CH251 CH252 CJ021 CJ022 CJ101 CJ102 CJ131 CJ291 CJ292 CQ001 CQ002 DA161 DA162 DB211 DB212 DB221 DB222 DG261 DG262 DG301 DG302 DL032 DL121 DL122 DL152 HA446 KA04 LA02 MA10 MA12 MA14 NA07 PA19 PB05 PB07 PB09

Claims (5)

[Claims] An acrylic monomer (a1) having a hydroxyl group in the presence of an azo group-containing silicone macroinitiator, or
Hydroxyl-containing silicone acrylic block polymer (A) obtained by polymerizing a mixture of the acrylic monomer (a1) and another ethylenically unsaturated monomer (a2), a polyisocyanate curing agent and / or melamine curing A curing agent for a water-repellent coating, comprising an agent (B) and an aggregate of primary particles having an average particle size of several tens of nm, and inorganic particles (C) having an average particle size of 1 to 10 μm. Resin composition. 2. The curable resin composition for a water-repellent coating according to claim 1, wherein the inorganic particles (C) are hydrophobic silica. 3. The curable resin composition for a water-repellent coating according to claim 1, further comprising an acrylic polyol (D). 4. The curable resin composition for a water-repellent coating according to claim 1, further comprising a silicone oil (E). 5. A coated product obtained by applying the curable resin composition for a water-repellent coating according to claim 1, 2, 3, or 4.