JPH08283663A - Coating composition for building material - Google Patents

Abstract

PURPOSE: To obtain a coating composition composed of a specific hydrolyzable perfluoroalkylsilane, polyorganosiloxane and catalyst component, excellent in water repellency, oil repellency, antifouling property, etc., and useful for a stone material, concrete, etc. CONSTITUTION: This composition is obtained by compounding (A) hydrolyzable perfluoroalkylsilane of the formula [R<1> (CH2 )p ]a SiR<2> 4-a [R<1> is a 1-20C perfluoroalkyl; R<2> is a 1-8C hydrolyzable group; (a) is an integer of 1-3; (p) is an arbitrary integer], (B) a polyorganosiloxane of formula I or formula II [R<3> to R<6> are each a 1-6C alkyl; (m) is an integer of 0-6; (n) is an integer of 3-8] (preferably, hexamethyldisiloxane) and (C) a catalyst component accelerating the hydrolysis of the component A (preferably, tetrabutyl titanate). Further, compounding ratios of each of the component are as follows: 100,000 pts.wt., preferably 50-50,000 pts.wt. of the component B and preferably 0.01-100 pts.wt., especially 0.05-10 pts.wt. of the component C based on 100 pts.wt. of the component A.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating composition for various building materials such as stone, concrete and mortar. More specifically, it is for a building material excellent in water repellency, oil repellency, anti-staining property and uniform coating property. Coating composition.

[0002]

TECHNICAL BACKGROUND OF THE INVENTION AND ITS PROBLEMS Conventionally, water repellency, various stone materials, concrete, mortar and various building materials,
Acrylic resin coating materials and urethane resin coating materials have been used for the purpose of imparting oil repellency and anti-staining property. Although these have water repellency and oil repellency, they have a drawback that their weather resistance is inferior to that of silicone-based coating materials, and their aesthetic appearance is likely to be impaired over time.
Further, a method of applying water repellent to a porous inorganic material such as concrete by applying a coating material in which a silane compound or polysiloxane is mixed with an organic solvent or a hydrocarbon-based solvent is well known. JP-A-57-126878, JP-A-62-197369, JP-A-1-292089, JP-A-2-70787, JP-A-2-150477), the oil repellency of these compositions is It was not durable for a long time, and its contamination prevention property was not satisfactory. Furthermore, in order to improve oil repellency, when a coating material in which a perfluoroalkylsilane is mixed with an organic solvent or a hydrocarbon solvent is applied to various building materials such as stone, concrete and mortar, There is a problem that cissing occurs on a smooth surface such as a polished surface and the coating material cannot be applied uniformly.

[0003]

An object of the present invention is to solve the above-mentioned problems, to uniformly coat various building materials, and to have a practically satisfactory level of water repellency, oil repellency, and stain prevention coating for building materials. It is intended to provide a composition.

[0004]

As a result of various studies to achieve the above object, the inventors of the present invention can apply it uniformly to various building materials such as stones, concrete, and mortar without causing cissing, and have water repellency, The present invention has been completed by finding a coating composition for a building material which is excellent in oil repellency and stain resistance. That is, the present invention provides the following components (A), (B) and
A coating composition for a building material, which comprises (C). (A) General formula: [R ¹ (CH ₂ ) _p ] _a SiR ² _4-a (In the formula, R ¹ is a perfluoroalkyl group having 1 to 20 carbon atoms,
R ² is a hydrolyzable group having 1 to 8 carbon atoms, a is an integer of 1 to 3,
p is an arbitrary integer. ) Hydrolyzable perfluoroalkylsilane (B) Polyorganosiloxane represented by structural formula (I) or (II)

[0005]

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(In the formula, R ^{3 to} R ⁶ are alkyl groups having 1 to ⁶ carbon atoms and may be the same or different. M is 0.
Is an integer of 6 and n is an integer of 3 to 8. ) (C) A catalyst component that accelerates the hydrolysis reaction of the component (A) The present invention is described in detail below.

In the present invention, the material of the target building material is not particularly limited as long as it is a commonly used material. Materials for building materials include various inorganic materials such as stones, concrete, mortar, tiles, bricks, metal materials such as aluminum, iron and stainless steel, and their surfaces such as synthetic resin spraying materials and siliceous spraying materials. Examples include those that have been sprayed, and those that have been further coated with a synthetic resin paint or the like. Since the coating composition of the present invention can form a uniform silicone layer, it is particularly preferably used for the smooth surface such as a polished surface of stone among the above.

The component (A) used in the present invention is a hydrolyzable perfluoroalkylsilane represented by the following general formula. [R ¹ (CH ₂ ) _p ] _a SiR ² _4-a Here, R ¹ is a perfluoroalkyl group having 1 to 20 carbon atoms, and in view of imparting water repellency and oil repellency, R ¹ (CH ₂ ) _p ] _a It is preferable that the carbon number is 12 or less in order not to reduce the permeability to the substrate. That is, -C ₃ F ₇ , -C
₄ F _9, -C ₆ F _13, the like _{-C 8 F 17, C 10 F} 21, C 12 F 23 can be exemplified, water repellency, oil repellency, in terms of permeability, especially -C ₆
F _13, -C ₈ F ₁₇ is preferred. R ² is a hydrolyzable group having 1 to 8 carbon atoms, and examples thereof include alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group. Further, a is an integer of 1 to 3 and p is an arbitrary integer.

The component (B) used in the present invention has the following structural formula
It is a polyorganosiloxane represented by (I) or (II).

[0010]

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Here, R ^{3 to} R ⁶ are alkyl groups having 1 to ⁶ carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group and a butyl group, but they may be the same or different. Of these, a methyl group and an ethyl group are preferable. In addition, m is an integer of 0 to 6 and n is an integer of 3 to 8. Particularly, in the structural formula (I), hexamethyldisiloxane in which R ³ and R ⁵ are methyl groups and m is 0 is (A)
It is most preferable as the component (B) from the viewpoints of solubility with components, wettability, uniformity, volatility and the like. The amount of component (B) is
The amount is 1 to 100,000 parts by weight, preferably 50 to 50,000 parts by weight, relative to 100 parts by weight of the component (A).

As the curing catalyst for the component (C) of the present invention, a general curing catalyst used in condensation-curable silicone compositions can be used, and organic amines such as triethanolamine; tin octylate, zinc octylate. Carboxylic acid metal salts such as; Organotin compounds such as dibutyltin dilaurate and dibutyltin octoate; Titanate esters such as tetrabutyl titanate and tetrapropyl titanate; Quaternary ammonium compounds such as quaternary ammonium carboxylates; γ-aminopropyl Examples thereof include amine-based silane coupling agents such as triethoxysilane and N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, and dibutyltin dilaurate or tetrabutyl titanate is preferable from the viewpoint of easy handling. Two or more of these catalysts may be used in combination, and the amine-based silane coupling agent is also effective in improving the adhesion to the wall surface of the protective film, and therefore it is preferably used in combination with another catalyst. The compounding amount of the catalyst is 0.01 based on 100 parts by weight of the component (A) based on the curing speed and pot life of the coating material.
-100 parts by weight is preferable, and 0.05-10 parts by weight is particularly preferable.

[0013]

EFFECTS OF THE INVENTION According to the present invention, a coating composition for a building material, which has water repellency and oil repellency that are durable for a long time and is excellent in anti-staining property, can be obtained. Further, the coating composition for a building material of the present invention does not cause cissing even on a smooth surface such as a polished surface of a stone material, and thus can be applied uniformly to various building materials.

[0014]

EXAMPLES The present invention will be described below with reference to examples.
In addition, the part in an Example represents a weight part and the viscosity shows the value of 25 degreeC. Examples 1 to 4 and Comparative Examples 1 to 5 Silicone coating compositions were prepared with the formulations shown in Table 1, applied to natural marble, and physical properties and characteristics were evaluated by the methods described below. The evaluation results are shown in Table 2. The silicone hydrolyzate (A-1) used in Comparative Example 5 was synthesized by the following Synthesis Example 1. Synthesis Example 1 Methyltrimethoxysilane was placed in a flask equipped with a stirrer, a heating jacket, a reflux condenser and a dropping funnel.
60 g (10 mol), 200 g of methanol and methyltrichlorosilane were charged so that the hydrochloric acid content became 50 ppm, and 171 g (9.5 mol) of water was gradually added dropwise using a dropping funnel while stirring. Hold at reflux temperature (about 68-72 ° C) for 4 hours,
Hydrolysis and condensation reactions were performed. After distilling off the volatile components under the conditions of normal pressure and 100 ° C, the pressure is gradually reduced to 40 mmHg,
The volatile components were further distilled off under reduced pressure at 150 ° C,
20 cP of silicone (A-1) was obtained.

[Evaluation Method] Applicability: 200 g / m ² of the coating composition was applied to natural marble (Bianco Carrara), and how the surface was coated from that point to drying was visually evaluated. Dryability: 200 g / m ² of the coating composition was applied to natural marble (Bianco Carrara), and the drying time from that point until drying was evaluated. Appearance after application: 200 g / m ² of the coating composition was applied to natural marble (Bianco Carrara), and after drying, the appearance of the base material (natural marble) was visually evaluated for change. Oil-wipeability: 200 g / m ² of coating composition is applied to natural marble (Bianco Carrara), 20 ° C, 60% RH
After curing for 24 hours under the above condition, commercially available salad oil was dropped on the coated surface and left for 6 hours. After standing, the salad oil was wiped off with a tissue paper, and the degree of oil stain on the base material at that time was visually evaluated. Water repellency: 200 g / m ² of coating composition was applied to natural marble (Bianco Carrara) and cured for 24 hours at 20 ° C and 60% RH, and then ion-exchanged water was added dropwise to the coated surface to obtain the contact angle. Was measured. The contact angle was measured three times, and the variation of the contact angle was also determined in order to evaluate the average value and the uniformity of the measured values. Oil repellency: Coating composition 200g / m ^{2 on} natural marble (Bianco Carrara) and curing for 24 hours at 20 ° C and 60% RH, then diiodomethane (CH
₂ I ₂ ) was dropped and the contact angle was measured. The contact angle was measured three times, and the variation of the contact angle was also determined in order to evaluate the average value and the uniformity of the measured values.

[0016]

[Table 1]

[0017]

[Table 2]

Claims (3)

[Claims] 1. A coating composition for a building material, which comprises the following components (A), (B) and (C). (A) General formula: [R ¹ (CH ₂ ) _p ] _a SiR ² _4-a (In the formula, R ¹ is a perfluoroalkyl group having 1 to 20 carbon atoms,
R ² is a hydrolyzable group having 1 to 8 carbon atoms, a is an integer of 1 to 3,
p is an arbitrary integer. ) Hydrolyzable perfluoroalkylsilane (B) Polyorganosiloxane represented by structural formula (I) or (II) (In the formula, R ^{3 to} R ⁶ are alkyl groups having 1 to ⁶ carbon atoms and may be the same or different. M is an integer of 0 to 6,
n is an integer of 3-8. ) (C) (A) Catalyst component that accelerates the hydrolysis reaction of components 2. The coating composition for building materials according to claim 1, wherein the component (B) is hexamethyldisiloxane. 3. The coating composition for building materials according to claim 1, wherein the component (C) is tetrabutyl titanate.