JPH07188561A - Room temperature curing organopolysiloxane composition - Google Patents

Abstract

PURPOSE:To obtain a room temperature curing organopolysiloxane composition, containing a specific diorganopolysiloxane, etc., excellent in fouling resistance of the surface of a cured product and useful as a sealing agent, etc. CONSTITUTION:This composition contains (A) 100 pts.wt. diorganopolysiloxane having both molecular ends blocked with hydroxyl groups, (B) preferably 0.5-30 pts.wt. organosilicon compound (a partial hydrolyzate) having >=3 hydrolyzable groups bound to silicon atom in one molecule, (C) preferably 0.5-5 pts.wt. organosilicon compound, containing fluorine and expressed by formula I or II Me us methyl; Rf<1> is a perfluoroalkyl or a perfluoroxyalkyl; Rf<2> is a perfluoroalkyl or a perfluoroxyalkylene; R<1> and R<4> each us a bivalent organic group; R<2> and R<3> each is a (substituted) monovalent hydrocarbon; R<5> is H or methyl; X is a hydrolyzable group; (a), (c) and (e) each is 0-2; (b), (d) and (f) each is 1-3; [(a)+(b)], [(c)+(d)] and [(e)+(f)] each is <=3} and (D) preferably 0.1-5 pts.wt. photopolymerization initiator such as acetophenone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to room temperature curing in which a rubbery elastic body is cured by being kept at room temperature by the action of moisture in the air while being stably stored in a fluid state under a closed condition. Organopolysiloxane composition.

[0002]

2. Description of the Related Art Heretofore, room temperature-curable organopolysiloxane compositions as described above have been widely used as sealing materials, coating materials, adhesives, etc. in the fields of construction industry, machine industry or electric industry. . However, the rubber elastic body cured product formed from this composition is liable to be contaminated on the surface and its surroundings, and when used in the above-mentioned applications, for example, there is a drawback such as impairing the aesthetics of a building. Is desired.

[0003]

Various additives have been investigated in order to improve this drawback. For example, a surfactant having a polyoxyethylene group, a sorbitan residue, a disaccharide residue, or the like (JP-A-56). -76452, JP-A-56-76453), a method of incorporating a surfactant having at least one fluorine atom in the molecule (see JP-A-58-167647), etc. into the composition, A method in which a surfactant having at least one fluorine atom in the molecule and an organic silicon compound having an amino group are combined and blended (JP-A-61-340).
No. 62) has been proposed, but these cannot prevent contamination of the surface of the cured product or its vicinity for a long period of time.

Therefore, an object of the present invention is to provide a room temperature curable organopolysiloxane composition capable of forming a cured product which is not contaminated on the surface or in the vicinity thereof for a long period of time.

[0005]

The present invention provides a fluorine-containing organosilicon compound having a (meth) acrylic group and a (meth) acrylic group and a hydrolyzable group in addition to a conventional room-temperature-curable organopolysiloxane, and The addition of a photopolymerization initiator has succeeded in solving the above problems.

That is, according to the present invention, (A) a diorganopolysiloxane in which both ends of the molecular chain are blocked with hydroxyl groups,
(B) an organosilicon compound having at least three hydrolyzable groups bonded to a silicon atom in one molecule or a partial hydrolyzate thereof, (C) the following general formula (1) or (2):

[0007]

[Chemical 3]

[0008]

[Chemical 4]

In the formula, Me is a methyl group, Rf ¹ is a perfluoroalkyl group or a perfluorooxyalkyl group,
Rf ² is a perfluoroalkylene group or a perfluorooxyalkylene group, R ¹ and R ⁴ may be the same or different and is a divalent organic group, and R ² and R ³ are the same or different. Also, an unsubstituted or substituted monovalent hydrocarbon group, R ⁵ is a hydrogen atom or a methyl group, X is a hydrolyzable group, a, c and e are integers of 0 to 2 respectively, b, d and f. Is
Each is an integer of 1 to 3, a + b, c + d, e + f
Are each 3 or less, and a room-temperature-curable organopolysiloxane composition comprising a fluorine-containing organosilicon compound represented by and (D) a photopolymerization initiator is provided.

The composition of the present invention is cured by water in the air to form a cured product of a rubber elastic body. The fluorine-containing organosilicon compound of the component (C) contained in the cured product is Since it has a (meth) acrylic group, it has photocurability. Therefore, when the composition of the present invention is used outdoors as a sealing material or the like, the component (C) distributed on the surface of the cured product is cured by sunlight, and the cured product of the rubber elastic body previously formed is The coating prevents contaminants such as uncured components from seeping out from the inside, thereby preventing contamination of, for example, the sealant surface or its periphery.

Component (A) The component (A), a diorganopolysiloxane, is one in which both ends of the molecular chain are blocked with hydroxyl groups, which has been conventionally used as a base component for room temperature curable organopolysiloxane compositions. It is used from. That is, the hydroxyl group at the molecular end of the polysiloxane is condensed with the hydrolyzable group contained in the component (B) described later to form a cured product of a rubber-like elastic body.

Such a diorganopolysiloxane is represented by the following general formula (3):

[Chemical 5] In the formula, R ⁶ and R ⁷ may be the same or different,
It is an unsubstituted or substituted monovalent hydrocarbon group, and n is a positive integer.

In the above general formula (3), R ⁶ and R ⁷
Examples of the monovalent hydrocarbon group include a methyl group, an ethyl group,
Alkyl group such as propyl group; Cycloalkyl group such as cyclohexyl group; Alkenyl group such as vinyl group and allyl group;
An aryl group such as a phenyl group and a tolyl group; an aralkyl group such as a benzyl group and a phenylethyl group; and a group in which at least a part of hydrogen atoms of these groups are substituted with a halogen atom, for example, a chloromethyl group, 3,3,3. A 3-trifluoropropyl group etc. can be mentioned.

Further, this diorganopolysiloxane is
The viscosity at 25 ° C is preferably in the range of 1,000 to 10,000 cSt, and therefore n in the general formula (3) is 10
It is preferably an integer equal to or greater than the above.

Component (B) The organosilicon compound as the component (B) is one having at least three hydrolyzable groups bonded to a silicon atom in one molecule, or a partial hydrolyzate thereof. As described above, it is a component that acts as a crosslinking agent. That is, in the presence of moisture (for example, moisture contained in air), the hydrolyzable group and the hydroxyl group in the component (A) described above condense to form a cured product. Examples of the hydrolyzable group include an alkoxy group, a ketoxime group, an acyloxy group,
Examples thereof include an amide group, an aminoxy group and an alkenyloxy group.

In the present invention, the organosilicon compound may be either a silane or a siloxane compound,
Specifically, the following compounds can be used alone or in combination of two or more kinds. Alkoxysilanes such as methyltrimethoxysilane, vinyltriethoxysilane and 3-chloropropyltrimethoxysilane.
Ketoxime silanes such as methyltris (dimethylketoxime) silane, methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane, and tetra (methylethylketoxime) silane. Acyloxysilanes such as vinyltriacetoxysilane, methyltriacetoxysilane and phenyltriacetoxysilane. Phenyltris (N-methylacetamide) silane, vinyltris (N-methylacetamide)
Amidosilane such as silane. Aminooxysilanes such as methyltris (N, N-dimethylaminoxy) silane and vinyltris (N, N-diethylaminoxy) silane. Alkenyloxysilanes such as vinyltriisopropenoxysilane, methyltriisobutenoxysilane and phenyltricyclohexanoxysilane. One or two of the above silanes
Partial or more partial hydrolyzate.

The component (B) is usually added in an amount of 0.5 to 30 parts by weight per 100 parts by weight of the component (A). If the blending amount is less than 0.5 part by weight, gelation may occur during production or storage of the composition, or the cured product of the elastic body may not exhibit desired physical properties. If it is blended in a larger amount than the parts, the shrinkage rate of the composition upon curing may increase and the elasticity of the resulting cured product may decrease.

Component (C) The fluorine-containing organosilicon compound of component (C) is represented by the above general formula (1) or (2), and is a compound having a property of being cured by light irradiation.

In the general formulas (1) and (2), R ¹ and R
⁴ is a divalent organic group, specifically, a methylene group,
Alkylene groups such as ethylene and propylene groups, cyclopentylene groups, cycloalkylene groups such as cyclohexylene groups, arylene groups such as phenylene groups, -ROR-, -R
Ether bond-containing group such as _{SR-, -RCO 2 R -, -} R
Ester bond-containing groups such as SO ₃ R-, ketone bond-containing groups such as -RCOR-, -RCON (R ') R-, -RS
Examples thereof include amide bond-containing groups such as O ₂ N (R ′) R—. In the above, R is a divalent hydrocarbon group, for example, an alkylene group such as a methylene group, an ethylene group and a propylene group, a cycloalkylene group such as a cyclopentylene group and a cyclohexylene group, and an arylene group such as a phenylene group. , R'is a monovalent hydrocarbon group such as an alkyl group such as a methyl group, an ethyl group and a propyl group, a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, an alkenyl group such as a vinyl group and an allyl group, a phenyl group and a tolyl group. And aryl groups, and groups in which at least some of the hydrogen atoms of these groups have been replaced with halogen atoms and the like.

R ² and R ³ are unsubstituted or substituted monovalent hydrocarbon groups such as alkyl groups such as methyl group, ethyl group and propyl group; cycloalkyl groups such as cyclohexyl group; vinyl group and allyl group. , Alkenyl groups such as isopropenoxy group; aryl groups such as phenyl group and tolyl group; aralkyl groups such as benzyl group and phenylethyl group;
And groups in which some of the hydrogen atoms of these groups have been replaced with halogen atoms, such as the 3,3,3-trifluoropropyl group, 6,6,6,5,5,4,4,3 3-nonafluorohexyl group, chloromethyl group, 3-chloropropyl group and the like.

R ⁵ is a hydrogen atom or a methyl group, and X is a hydrolyzable group. This hydrolyzable group is the same group as exemplified for the hydrolyzable group in the component (B), and specific examples thereof include those represented by the following formula.

[0022]

[Chemical 6]

In the above formula, R ⁸ and R ⁹ are hydrogen atoms or monovalent hydrocarbon groups. As the monovalent hydrocarbon group, an alkyl group such as a methyl group, an ethyl group or a propyl group,
Examples thereof include cycloalkyl groups such as cyclopentyl group and cyclohexyl group, and aryl groups such as phenyl group and tolyl group.

Further, in the general formula (1), Rf ¹ is a monovalent fluorine-containing group, which is a perfluoroalkyl group or a perfluorooxyalkyl group. Examples of the perfluoroalkyl group are those represented by the following formula (1a): C _n F _{2n + 1} − (1a), wherein n is a positive integer, preferably an integer of 1 to 16. Can be illustrated.

The perfluorooxyalkyl group is represented by the following formulas (1b) to (1d):

[Chemical 7] In the formula, Y is F or CF ₃ , and p, q, r and s
Are each a positive integer. Here, p is 1 to 30, and q is 1 to 1.
5, r is preferably 1 to 20, and s is preferably an integer in the range of 1 to 20.

In the general formula (2), Rf ² is a divalent fluorine-containing group and is a perfluoroalkylene group or a perfluorooxyalkylene group.

The perfluoroalkylene group is represented by, for example, the following formula (2a): —C _m F _2m — (2a) wherein m is a positive integer, preferably an integer of 1 to 16. The thing can be illustrated.

As the perfluorooxyalkylene group,
Formulas (2b) to (2d) below:

[Chemical 8] In the formula, Y is F or CF ₃ , and p, q, r, s, and t are each positive integers. Here, p is 1 to 30, and q is 1 to
It is desirable that 15, r is 1 to 8, s is 1 to 20, and t is an integer in the range of 1 to 20.

In the general formulas (1) and (2), a
A to c are integers of 0 to 2 and b, d and f are integers of 1 to 3, respectively, under the condition that a + b, c + d and e + f are each 3 or less. . Therefore, the fluorine-containing organosilicon compound as the component (C) does not necessarily have the hydrolyzable group X,
When the compound has a hydrolyzable group X, the compound also has condensation curability, so that the component (C) is incorporated and retained in the cured product, so that the effect of preventing contamination due to stable photocuring is obtained. Is stably expressed.

In the above-mentioned component (C), the fluorine-containing organosilicon compound represented by the general formula (1) or (2) may be used alone or in combination of two or more kinds. Good. This component (C)
Is usually added in an amount of 0.5 to 5 parts by weight per 100 parts by weight of the component (A). If the blending amount is less than 0.1 part by weight, a sufficient coating layer is not formed on the surface of the condensation cured product even when the condensation cured product is exposed to light, and the contamination cannot be effectively prevented. Also, if more than 15 parts by weight is blended,
Not only the physical properties of the obtained elastic body cured product deteriorate, but also it is economically disadvantageous.

The fluorine-containing organosilicon compound represented by the general formula (1) has the following formula (4):

[Chemical 9] In the formula, Rf ¹ , R ¹ , R ² , X and a are, as shown in the general formula (1), a hydrolyzable silane compound represented by the following general formula (5):

[Chemical 10] It can be produced by reacting with a silane compound represented by the formula (1) in the presence of a condensation catalyst.

The fluorine-containing organosilicon compound represented by the general formula (2) has the following formula (6):

[Chemical 11] In the formula, R ¹ , R ² , Rf ² , X and c, e represent a hydrolyzable silane compound represented by the following general formula (2), for example, represented by the general formula (5). It can be produced by reacting the silane compound with the condensation catalyst in the presence of a condensation catalyst.

When the fluorine-containing organosilicon compound represented by the general formula (1) or (2) is produced according to the above-mentioned method, in order to prevent the hydrolyzable group X from remaining at all, the general formula (5 The silane compound represented by the formula (4) may be used in excess with respect to the hydrolyzable silane compound represented by the general formula (4) or (6).

The above condensation reaction is carried out at room temperature to 80 ° C.
Under normal pressure or reduced pressure (eg 20mmHg-200mmHg)
It is suitable to carry out. The condensation reaction is carried out using a condensation catalyst, and known catalysts may be used as such a catalyst, for example, lead-2-ethyloctoate, dibutyltin diacetate, dibutyltin dilaurate,
Butyltin tri-2-ethylhexoate, iron-2-ethylhexoate, cobalt-2-ethylhexoate, manganese-2-ethylhexoate, zinc-2-ethylhexoate, caprylic acid No. 1 Metal salts of organic carboxylic acids such as tin, tin naphthenate, tin oleate, tin butyrate, titanium naphthenate, zinc naphthenate, cobalt naphthenate and zinc stearate; tetrabutyl titanate, tetra-2-ethylhexyl titanate, tri Organic titanate esters such as ethanolamine titanate and tetra (isopropenyloxy) titanate; organotitanium compounds such as organosiloxytitanium and β-carbonyltitanium; lower fatty acids of alkali metals such as potassium acetate, sodium acetate and lithium oxalate; dimethyl Hydroxyamine, A dialkylhydroxylamine such as ethylhydroxylamine; tetramethylguanidine, and a guanidyl compound such as a silane or siloxane containing a guanidyl group such as the following formulas (7) and (8) are used singly or in combination of two or more. be able to. The amount of these condensation catalysts added is determined by the formula (4)
Alternatively, it is used in an amount of about 0.001 to 5.0 parts by weight per 100 parts by weight of the hydrolyzable silane compound of (6).

[0035]

[Chemical 12]

The photopolymerization initiator of the component (D) component (D) is for promoting the photopolymerization of acryl groups, in order to accelerate the photopolymerization of the fluorinated organosilicon compound of the component (C) It is to be blended. As this photopolymerization initiator, a known compound that has been conventionally used can be used. For example, acetophenone, propiophenone, benzophenone, xanthol, fluorein, benzaldehyde,
Anthraquinone, triphenylamine, 4-methylacetophenone, 3-pentylacetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-allylacetophenone, p-diacetylbenzene, 3-methoxybenzophenone, 4-methylbenzophenone, 4
-Chlorobenzophenone, 4,4-dimethoxybenzophenone, 4-chloro-4-benzylbenzophenone, 3
-Chloroxanthone, 3,9-dichloroxanthone, 3-chloro-8-nonylxanthone, benzoin, benzoin methyl ether, benzoin butyl ether, bis (4-dimethylaminophenyl) ketone, benzyl methoxy ketal, 2-chlorothio. Xanthone, diethyl acetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl [4- (methylthio) phenyl] 2-morpholino-1-propanone,
Examples include 2,2-dimethoxy-2-phenylacetophenone and diethoxyacetophenone.

The blending amount of the component (D) is preferably 0.01 to 10 parts by weight, particularly 0.1 to 5 parts by weight, per 100 parts by weight of the organopolysiloxane of the component (A). If the blending amount is less than 0.01 parts by weight, the component (C)
If the photopolymerization does not proceed effectively and the amount is more than 10 parts by weight, the strength of the obtained elastic body cured product tends to be low.

Other Compounding Components In the present invention, in addition to the above-mentioned essential components (A) to (D), the compound itself may be used as long as the purpose of preventing contamination of the surface of the cured product or its surroundings is not impaired. Known additives can be appropriately added. For example, in order to accelerate the condensation curing reaction between the hydroxyl group in the component (A) and the hydrolyzable group in the component (B), an organometallic compound,
A condensation catalyst such as a titanium chelate compound or a guanidyl group-containing compound (specifically, the same as the condensation catalyst for producing the component (C) may be used). Further, in order to adjust the physical properties of the desired rubber-like elastic material, fumed silica, precipitated silica, titanium dioxide, aluminum oxide,
Reinforcing agents such as quartz powder, talc and bentonite, fibrous fillers such as asbestos, glass fibers and organic fibers can be used. In addition, oil resistance improvers such as potassium methacrylate; colorants; heat resistance improvers such as red iron oxide and cerium oxide; cold resistance improvers; thixotropic agents such as polyethers; dehydrating agents; adhesion improvers; , Can be blended according to the purpose.

Room Temperature Curable Organopolysiloxane Composition The composition of the present invention is obtained as a one-pack type room temperature curable composition by uniformly mixing the above components in a dry atmosphere. This composition, when exposed to air, undergoes a crosslinking reaction due to moisture in the air to cure into a rubber elastic body, and when the cured product is exposed to light such as by being left outdoors, the component (C A protective coating is formed by the curing of (1), and contamination due to exudation of unreacted components from the inside of the cured product is effectively prevented. Therefore, since the cured product is non-staining, the composition of the present invention is very effectively used particularly for applications such as sealing materials for building exteriors and coating materials.

[0040]

EXAMPLES In the following examples, "parts" means "parts by weight" unless otherwise specified, and the viscosity is a value measured at 25 ° C.

Examples 1 to 3, Comparative Example 1 100 parts of dimethylpolysiloxane (viscosity: 20,200 cSt) in which both ends of the molecular chain were blocked with hydroxyl groups, fumed silica whose surface was treated with hexamethyldisilazane (specific surface area: 150m ² / g) 12 parts, titanium dioxide 1.5 parts were mixed and passed through a triple roll once, and then 7 parts of methyltributanoxime silane and 0.1 parts of dibutyltin dioctoate were added anhydrous. A base composition (Comparative Example 1) was obtained by degassing and mixing in the state of.

This base composition has the following formula:

[Chemical 13] Fluorine-containing organosilicon compound represented by, respectively, 1.
0 parts (Example 1), 3.0 parts (Example 2), 5.0 parts (Example 3), blended, and further added diethoxyacetophenone 2.0 parts, room temperature curable composition Was prepared.

Next, two square granites (size 300
(300 × 15 mm) are arranged so as to face each other with a gap of 15 mm, and the curable compositions of Examples 1 to 3 prepared above are filled in the gap (filling dimension 300 × 300 ×). 15m
m), the composition was cured to prepare a test body. Also,
As Comparative Example 1, a test body was prepared in the same manner using only the base composition in which the above-mentioned fluorine-containing organosilicon compound was not blended.

The test pieces obtained above were left outdoors for 3 months, 6 months, and 12 months, and the generation of stains on the surface of the cured product and its periphery was examined. Results were obtained.

Example 4, Comparative Example 2 100 parts of dimethylpolysiloxane having both ends of the molecular chain blocked with hydroxyl groups (viscosity: 20,500 cSt), fumed silica having a surface treated with hexamethyldisilazane (specific surface area: 150 m ² / g) 12 parts, titanium dioxide 1.5 parts were mixed and passed through a triple roll once, and then vinyltriisopropenoxysilane 6 parts, guanidyl-containing silane represented by the above formula (7). A base composition (Comparative Example 2) was prepared by degassing and mixing 0.5 parts, in an anhydrous state.

This base composition has the following formula:

[Chemical 14] A room temperature-curable composition was prepared by adding 3.0 parts of a fluorine-containing organosilicon compound represented by and 2.0 parts of diethoxyacetophenone (Example 4).

Using this curable composition, a test body was prepared in the same manner as in Example 1 and the occurrence of stains was examined. Further, with respect to the above-mentioned base composition (Comparative Example 2), the occurrence of stains was examined in the same manner. The results are shown in Table 1.

Example 5 As the fluorine-containing organosilicon compound, the following formula:

[Chemical 15] A room temperature-curable composition was prepared in the same manner as in Example 4 except that 3.0 parts of the above-mentioned compound was used, and a test sample was prepared to examine the occurrence of stains. The results are shown in Table 1.

Example 6 As the fluorine-containing organosilicon compound, the following formula:

[Chemical 16] A room temperature-curable composition was prepared in the same manner as in Example 4 except that 3.0 parts of the above-mentioned compound was used, and a test sample was prepared to examine the occurrence of stains. The results are shown in Table 1.

Example 7 100 parts of dimethylpolysiloxane in which both ends of the molecular chain were blocked with hydroxyl groups (viscosity: 21,200 cSt), fumed silica whose surface was treated with hexamethyldisilazane (specific surface area: 120 m ² / g) 12 , 1.5 parts of titanium dioxide were mixed and passed through a triple roll once, and then 7 parts of methyltributanoxime silane and 0.1 part of dibutyltin dioctoate were degassed and mixed in an anhydrous state. By doing so, a base composition was prepared.

This base composition has the following formula:

[Chemical 17] A room temperature-curable composition was prepared by adding 3.0 parts of a fluorine-containing organosilicon compound represented by and 2.0 parts of diethoxyacetophenone.

Using this curable composition, a test piece was prepared in the same manner as in Example 1, and the appearance of stain was examined by an outdoor exposure test. The results are shown in Table 1.

Example 8 As the fluorine-containing organosilicon compound, the one used in Example 7 and the following formula:

[Chemical 18] A room temperature curable composition was prepared in the same manner as in Example 7 except that 3.0 parts of a 1: 1 mixture with the compound represented by I checked the situation. The results are shown in Table 1.

[0054]

[Table 1] ◯: No stain was found Δ: Slight stain was found x: Significant stain was found

[0055]

According to the present invention, contamination of the surface of a cured product formed from a condensation-curable room temperature curable organopolysiloxane composition or in the vicinity thereof can be effectively prevented. Therefore, this composition is extremely useful as a sealing agent or an adhesive, particularly in construction.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location C08K 5/54 (72) Inventor Takashi Matsuda 1 Hitomi, Daiji, Matsuidada-cho, Usui-gun, Gunma 10 Shinetsu Chemical Industry Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Hirokazu Yamada No. 1 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Tsuneo Kimura Gunma Prefecture 1 Hitomi, Oita, Matsuida-cho, Usui-gun, Shin-Etsu Chemical Co., Ltd., Research Center for Silicone Electronic Materials (72) Inventor, Masatoshi Arai, 1-Kita Hitomi, Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. In-house

Claims (1)

[Claims] 1. A diorganopolysiloxane in which both ends of a molecular chain are blocked with hydroxyl groups, and (B) an organosilicon compound having at least three hydrolyzable groups bonded to a silicon atom in one molecule or a portion thereof. Hydrolyzate, (C) General formula (1) or (2) below: [Chemical 2] In the formula, Me is a methyl group, Rf ¹ is a perfluoroalkyl group or a perfluorooxyalkyl group, Rf ² is a perfluoroalkylene group or a perfluorooxyalkylene group, and R ¹ and R ⁴ are the same or different. ^{May be a} divalent organic group, R ² and R ³ may be the same or different, an unsubstituted or substituted monovalent hydrocarbon group, R ⁵ is a hydrogen atom or a methyl group, and X is , Hydrolyzable groups a, c, e are each an integer of 0 to 2, b, d, f are each an integer of 1 to 3, and a + b, c + d, e + f are each 3 or less. A room-temperature-curable organopolysiloxane composition comprising a fluorine-containing organosilicon compound (D) and a photopolymerization initiator (D).