JP3407815B2 - Room temperature curable organopolysiloxane composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room temperature-curable organopolysiloxane composition which is useful as a sealing material in the construction industry and the like. [0002] Room temperature-curable organopolysiloxane compositions which are stored in a hermetically sealed condition while maintaining their fluidity, but which cure at room temperature by moisture when exposed to the atmosphere to become rubber elastic materials are known. I have. This composition is widely used as a sealing material, a coating material, an adhesive or the like in the construction industry, the machine industry, or the electric industry. However, room temperature-curable organopolysiloxane compositions are:
When used as a sealing material or a coating material, there is a disadvantage that the surface of the obtained cured product is contaminated or mold is generated on the surface, which impairs the appearance of the surface and the surroundings. Particularly, the above composition is used in a bathroom, a kitchen, a washroom, etc., in an environment where air permeability is inferior and high in humidity, and where dirt and mold due to human residue, detergent or food or garbage are liable to occur, sealing materials, coating materials, adhesives, etc. When it is used, it has a drawback that it is particularly liable to be contaminated and mold is liable to be formed, so that the appearance is impaired and dirt and mold are difficult to remove. [0003] Therefore, it has been proposed to add various additives to improve the antifouling property and the antifungal property of the room temperature-curable organopolysiloxane composition. For example, a surfactant having a polyoxyethylene group, a sorbitan residue, a disaccharide residue or the like in order to improve the antifouling property (JP-A-56-76452).
JP, JP-A-56-76453); surfactant having at least one fluorine atom in the molecule (see JP-A-58-167647); interface having at least one fluorine atom in the molecule It has been proposed to add an activator and an organic silicon compound having an amino group (see JP-A-61-34062). However, although these additives are effective for a short period of time, they have failed to provide effective antifouling properties to the composition over a long period of time. Further, in order to improve the antifungal property, compositions such as benzimidazolyl-alkyl-carbamates (see JP-A-54-43260); organosilicon compounds having a tetraorganoguanidyl group ( It has been proposed to add a fungicide such as JP-A-57-18758). However, since these fungicides flow out of the cured product due to water, effective fungicides could not be obtained over a long period of time. [0005] Accordingly, an object of the present invention is to provide a cured product having excellent antifouling properties and antifungal properties over a long period of time, and to easily provide a cured product even if dirt or mold adheres. It is an object of the present invention to provide a room-temperature-curable organopolysiloxane composition from which a cured product that can be removed is obtained. SUMMARY OF THE INVENTION The present invention solves this problem by providing (a) a diorganopolysiloxane in which both ends of a molecular chain are terminated with a hydroxyl group, and (b) a bond to a silicon atom. At least one selected from the group consisting of an organosilicon compound having at least two hydrolyzable groups per molecule and a partial hydrolyzate thereof, (c) the following general formula (1): [In the formula, R ^1, which may be the same or different, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ²
An unsubstituted or substituted divalent hydrocarbon group having 1 to 8 carbon atoms (which may contain at least one selected from the group consisting of ether bond, amide bond and an imino bond), R ³ is May be the same or different and have 1 carbon atom
~ 8 unsubstituted or substituted divalent hydrocarbon groups, and Q is
Which may be the same or different, and is a monovalent alkyl ether group, Rf is a perfluoroalkyl group or a monovalent perfluoroalkyl ether group, and m is an integer of 1 to 3]. And (d) the following general formula (2): (Wherein, R ¹ , R ² , Rf and m are as defined above). An organopolysiloxane composition comprising an alkoxysilane represented by the formula: Hereinafter, the present invention will be described in detail. (a) Component As the component (a), for example, the following general formula (3): (Wherein R ⁴ may be the same or different and is an unsubstituted or substituted monovalent hydrocarbon group, and n is an integer of 10 or more). Examples of the unsubstituted or substituted monovalent hydrocarbon group R ⁴ contained in the general formula (3) include 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 an aryl group or an allyl group; an aryl group such as a phenyl group or a tolyl group;
Examples thereof include groups in which a hydrogen atom of these groups is substituted with a halogen atom such as chlorine and fluorine. The viscosity of the above organopolysiloxane is 2
It is preferably within the range of 25 to 500,000 cSt at 5 ° C, more preferably 1,000 to 10 at 25 ° C.
It is in the range of 000 cSt. (B) Component Examples of the organosilicon compound as the component (b) include silane and siloxane. Examples of the hydrolyzable group contained in the organosilicon compound include, for example, a methoxy group,
An alkoxy group such as an ethoxy group; a ketoxime group such as a dimethyl ketoxime group and a methyl ethyl ketoxime group;
Acyloxy groups such as acetoxy group; amino groups such as N-butylamino group and N, N-diethylamino group; amide groups such as N-methylacetamide group; N, N-dimethylaminooxy group and N, N-diethylaminoxy group And an alkenyloxy group such as an isopropenoxy group, an isobutenoxy group and a cyclohexenoxy group. Specific examples of the organosilicon compound include:
Alkoxysilanes such as methyltrimethoxysilane, vinyltriethoxysilane, 3-chloropropyltrimethoxysilane, and 3-aminopropyltriethoxysilane;
Ketoxime silanes such as methyltris (dimethylketoxime) silane, methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane and tetra (methylethylketoxime) silane; vinyltriacetoxysilane, methyltriacetoxysilane, phenyltriacetoxysilane, etc. Acyloxysilane; phenyltris (N-methylacetamido) silane, vinyltris (N-methylacetamido)
Amidosilanes such as silane; aminosilanes such as vinyltris (N-butylamino) silane and phenyltris (N, N-diethylamino) silane; methyltris (N, N-
Dimethylaminoxy) silane, vinyl tris (N, N-
Aminoxysilanes such as diethylaminoxy) silane; and alkenyloxysilanes such as vinyltriisopropenoxysilane, methyltriisobutenoxysilane, and phenyltricyclohexenoxysilane. These organosilicon compounds and partial hydrolysates thereof may be used alone or in combination of two or more. [0011] (b) the amount of the component, (a) 100 parts by weight of the component per 0. 5 to 30 parts by weight, the good Mashiku 1.0 to 1
0 parts by weight. If this amount is too small, the composition may gel during the preparation of the composition or during storage of the composition,
An elastic body obtained by curing the composition does not exhibit desired physical properties, for example, rubber elasticity. If the amount is too large, the shrinkage of the composition at the time of curing becomes large, and the elasticity of the obtained cured product decreases. (C) Component In the general formula (1), examples of the unsubstituted or substituted monovalent hydrocarbon group R ¹ having 1 to 8 carbon atoms include the groups exemplified as R ⁴ above. In the general formula (1), an unsubstituted or substituted divalent hydrocarbon group having 1 to 8 carbon atoms (however, it may contain at least one kind selected from the group consisting of an ether bond, an amide bond and an imino bond) Examples of ² include 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; an arylene group such as a phenylene group; and the following formula: -CH ₂ -O-CH ₂ CH ₂ CH _2- , -CONH- CH ₂ CH ₂ CH _{2-
, -CONH- CH 2 CH 2 -NH-} CH 2 CH 2 CH 2 - and the like. In the general formula (1), examples of the unsubstituted or substituted divalent hydrocarbon group R ³ include the alkylene group, cycloalkylene group and arylene group exemplified for R ² . In the general formula (1), examples of the monovalent alkyl ether group Q include, for example, the general formula:-(OR ⁵ ) _-a
-OR ⁶ [where R ⁵ may be the same or different,
A C ₁ -C ₄ alkylene group, R ⁶ is a hydrogen atom or a C ₁ -C ₈ alkyl group, and a is an integer of 1 to 30], and specific examples include-(OCH ₂ CH ₂ ) ₃ OCH ₃ , − (OCH ₂ CH ₂ ) ₆ OCH _{3
, - (OCH 2 CH 2)} 9 OCH 3, - (OCH 2 CH 2) 3 OH , and the like. In the general formula (1), Rf represents the general formula: C
_b F _{2b + 1-} [where b is an integer of 1 to 10], or a general formula:-(R ⁷
O) _c R ⁸ [where R ⁷ may be the same or different and is a C ₁ -C ₄ perfluoroalkylene group;
⁸ is a C _{1 to} C ₁₀ perfluoroalkyl group, and c is an integer of 1 to 10]. Examples of the perfluoroalkyl group include C ₈ F ₁₇ −, C ₄ F ₉ − and C ₆ F ₁₃
—, CF ₃ —, (CF ₃ ) ₂ CF— and the like. Examples of the monovalent perfluoroalkyl ether group include, for example, C ₃ F ₇ OCF (CF ₃ ) CF ₂ OCF (CF ₃ ) −, C ₃ F ₇ OCF
(CF ₃ ) CF ₂ OCF (CF ₃ ) CF _2- , C ₃ F ₇ OCF (C
F ₃ ) CF ₂ OCF ₂ CF _2- and the like. Specific examples of the component (c) are shown below. Embedded image Embedded image [0016] (c) the amount of the component per 100 parts by weight of component (a), 0. 1 to 15 parts by weight, the good Mashiku 0.1
-5 parts by weight. If the amount is too small, a cured product having excellent antifouling properties and mold resistance cannot be obtained over a long period of time, and if it is too large, a cured product having good rubber strength cannot be obtained. (D) Component In the general formula (2), R ¹ , R ² and Rf are as described above. Specific examples of the component (d) are shown below. Embedded image The (d) The amount of component, relative to 100 parts by weight of component (a), 0. 1 to 15 parts by weight, the good Mashiku 0.5
-5 parts by weight. If the amount is too small, a cured product having excellent antifouling properties and mold resistance cannot be obtained over a long period of time, and if it is too large, a cured product having good rubber elasticity cannot be obtained. Other Additives The organopolysiloxane composition of the present invention may contain , if necessary, known additives usually added to a condensation-curable room temperature-curable organopolysiloxane composition, for example, amines, Curing catalysts such as organic metal compounds such as quaternary ammonium salts and dibutyltin dioctoate, titanium chelate compounds, and guanidyl group-containing compounds [usually, component (a) 100
0.1 to 10 parts by weight per part by weight]; Reinforcing agent such as fumed silica, precipitated silica, titanium dioxide, aluminum oxide, quartz powder, talc, bentonite, and fibrous filler such as asbestos, glass fiber, organic fiber Inorganic fillers (usually 5 to 300 parts by weight per 100 parts by weight of component (a)); oil-resistance improvers such as potassium methacrylate; coloring agents; heat-resistance improvers such as red iron oxide and cerium oxide; Agents; thixotropic agents such as polyether; dehydrating agents;
An adhesiveness improver such as γ-aminopropyltriethoxysilane may be added. Preparation of Composition The composition of the present invention can be prepared , for example, by mixing a predetermined amount of the components (a) to (d) uniformly in a dry (ie, anhydrous) atmosphere to form a one-part composition. It is prepared as Also, for example,
A homogeneous mixture of the components (a), (c) and (d) and the component (b) may be prepared as a two-pack type composition separately packaged.
When the composition of the present invention is exposed to the atmosphere, the composition is cured by moisture in the atmosphere. Applications The room-temperature-curable organopolysiloxane composition of the present invention can be used, for example, as a sealing material for building materials such as building exteriors, bathrooms, kitchens, and other places where dirt and mold are likely to occur.
Useful for coatings, adhesives, etc. Examples of the present invention will be described below. In each example, “parts” indicates “parts by weight”, and the viscosity is a measured value at 25 ° C. In the following description, * was added to the number of the composition according to the comparative example. Compositions without an asterisk (*) are examples of the present invention. Examples 1, Comparative Examples 1 to 3 100 parts of dimethylpolysiloxane (viscosity: 20,200 cSt) having both molecular chains terminated with hydroxyl groups, and the surface treated with hexamethyldisilazane has a specific surface area of 150 m ^2.
/ G of fumed silica and 1 part / g of titanium dioxide.
5 parts were mixed. After kneading the resulting mixture, the mixture was passed through a three-roll mill once, and then the mixture was further mixed with 8 parts of methyltributanoxime silane and 0.1 part of dibutyltin dioctoate.
One part was defoamed and mixed in an anhydrous state to prepare composition I ^* . For 100 parts of composition I ^* , the following formula (4): And / or an organosiloxane represented by the following formula (5): Was added to the compositions shown in Table 1 to prepare compositions II ^{* to} IV. [Table 1] Rubber Properties Test Each of the compositions I ^{* to} IV was formed into a sheet having a thickness of 2 mm, and the resulting sheet was cured by leaving it for 7 days in an atmosphere at a temperature of 20 ° C. and a relative humidity of 55%. When formed into a body, each of these sheets cured to become a rubber elastic body. Each of these compositions was stable at room temperature for 6 months or more in a sealed state. Composition I after 6 months
^{* To} IV were each formed into a sheet having a thickness of 2 mm, and cured under the same conditions as above to obtain a rubber elastic body. The rubber properties of the cured product immediately after preparation of the composition and the cured product after the composition was aged for 6 months were measured in accordance with JIS-C-2123. The results are shown in Tables 2 and 3. [Table 2] [Table 3] Shear Adhesion Test As shown in FIG. 1, a test composition 2 is applied to an upper surface of one end of an adherend plate 1 made of various materials having dimensions of 100 × 25 × 1 mm and an area of 25 × 10 mm. I do. A thickness of 1 m is sandwiched between the applied composition 2 and 5 mm from the composition.
m Teflon plates 3, 3 'are placed as spacers, and another adherend plate 1' made of the same material and having the same dimensions as the adherend plate 1 is placed on the lower surface of one end of the Teflon plate 3, 3 mm in area with an area of 25 × 10 mm Are arranged so as to contact the composition 2. Next, an aluminum plate having a length extending over the two Teflon plates 3 and 3 'serving as a spacer is overlapped, and a central portion thereof (directly above the composition 2).
Put 500g of weight 4 on the plate. These are then converted to 20
The substrate 1 was left standing for 7 days in an atmosphere of
The composition 2 between 1 ′ is cured. Both ends of the test piece thus prepared are pulled in opposite directions by a tensile tester at a speed of 50 mm / sec to measure the shear adhesive strength. For each of the compositions I ^{* to} IV, measurement was performed on an adherend made of the material shown in Table 4, and the results shown in the table were obtained. [Table 4] Antifouling test Two square granites (dimensions 300 × 300 × 15 m)
m) was placed on a flat surface with its wide side facing down so that each side was parallel with a gap of 15 mm, and the gaps were filled with the compositions I ^{* to} IV (filling dimension 30).
(0 × 15 × 15 mm), and the composition was cured to prepare two test pieces each consisting of only granite and a cured product. The obtained specimens were placed outdoors for 3 months, 6 months, and 12 months.
After standing for a month, the surface of the cured product and the surroundings were stained and evaluated according to the following criteria. ：: No stain was found. Δ: Slight stain was found. X: Significant stain was found. [Table 5] Mold resistance test Compositions I ^{* to} IV prepared in the same manner as the above rubber physical property test
Was punched out into a circular sheet having a diameter of 30 mm, and the obtained circular sheet was subjected to JIS-Z-291.
1. Mold resistance was measured in accordance with "Mold resistance test method". In addition, regarding the sheet where mold has occurred,
Mold removal was attempted by a method of once wiping with a dry nonwoven fabric, and the mold removal was evaluated according to the following criteria. [Evaluation criteria for mold removability] A: Easily removable B: Removable X: Difficult to remove The results are shown in Table 6. [Table 6] Example 2, Comparative Examples 4 to 6 100 parts of dimethylpolysiloxane (viscosity: 20,500 cSt) terminated at both molecular chains with hydroxyl groups, the surface of which is treated with hexamethyldisilazane has a specific surface area of 150 m ^2.
/ G of fumed silica and 1 part / g of titanium dioxide.
5 parts were mixed. After kneading the resulting mixture, the mixture was passed through a three-roll mill once, and then the mixture was further mixed with 6 parts of vinyltriisopropenoxysilane and the following formula (6): A guanidyl group-containing silane (0.5 parts) was defoamed and mixed in an anhydrous state to prepare a composition V ^* . The following formula (7) was added to 100 parts of the composition V ^* : And / or an organosiloxane represented by the following formula (8): Were added to the compositions shown in Table 7 to prepare compositions VI ^{* to} VIII. [Table 7] Rubber Properties Test Each of the compositions V ^{* to} VIII was molded into a sheet having a thickness of 2 mm, and the resulting sheet was allowed to stand for 7 days in an atmosphere at a temperature of 20 ° C. and a relative humidity of 55% to be cured, thereby obtaining rubber elasticity. When formed into a body, each of these sheets cured to become a rubber elastic body. Each of these compositions was stable at room temperature for 6 months or more in a sealed state. After 6 months, each of the compositions V ^{* to} VIII was formed into a sheet having a thickness of 2 mm, and cured under the same conditions as above to obtain a rubber elastic body. The rubber properties of the cured composition immediately after preparation and the cured composition after aged for 6 months were measured in the same manner as in Example 1. The results are shown in Tables 8 and 9. [Table 8] [Table 9] Test for Shear Adhesion, Antifouling Property and Mold Resistance Each of the compositions V ^{* to} VIII was tested in the same manner as in Example 1. The results shown in Tables 10, 11 and 12 were obtained. Was done. [Table 10] [Table 11] [Table 12] Examples 3 to 5 100 parts of dimethylpolysiloxane (viscosity: 21,200 cSt) in which both ends of a molecular chain are terminated with a hydroxyl group were treated with hexamethyldisilazane on the surface, and the specific surface area was 120 m ^2.
/ G of fumed silica and 1 part / g of titanium dioxide.
After mixing 5 parts and passing through a three-roll mill once, the mixture is further mixed with 7 parts of methyltributanoxime silane, 0.1 part of dibutyltin dioctoate and the following formula (9): Was defoamed and mixed in an anhydrous state to obtain a composition A. In addition, this composition A was added to Table 13
The compositions IX to XI were prepared by adding 3 parts of any one of the alkoxysilanes shown in (1) to (3). [Table 13] Tests for antifouling property and mold resistance When the compositions IX to XI were tested in the same manner as in Example 1, the results shown in Tables 14 and 15 were obtained. [Table 14] [Table 15] The organopolysiloxane composition of the present invention which is curable at room temperature provides a cured product having excellent antifouling property and antifungal property for a long period of time. Therefore, when the composition is used as a sealing material, a coating material, or the like, the surface of the cured product and its surroundings are hardly stained and hardly generate mold, so that the initial appearance can be maintained for a long period of time. Further, the cured product can easily remove stains and mold from the surface even if they adhere to the surface.

[Brief description of the drawings] FIG. 1 is a schematic view of a specimen for an adhesion test. [Explanation of symbols] 1 Cover plate 1 'attached plate 2 Composition layer 3 Teflon board 3 'Teflon board 4 Weight

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koji Matsuda 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Hirokazu Yamada Usui, Gunma Prefecture 1-10, Hitomi, Matsuida-cho, Gunisho Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Toshio Takaai 1-10, Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone electronic material technology (56) References JP-A-61-34062 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 83/08 C08K 5/541 C09K 3/10

Claims (1)

(57) [Claims 1] (a) 100 parts by weight of diorganopolysiloxane terminated at both molecular chains with hydroxyl groups, (b) one hydrolyzable group bonded to a silicon atom at least one 0.5 selected from the group consisting of organic silicon compounds and partial hydrolyzate thereof having at least two in the molecule
30 parts by weight , (c) the following general formula (1): [In the formula, R ^1, which may be the same or different, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ²
An unsubstituted or substituted divalent hydrocarbon group having 1 to 8 carbon atoms (which may contain at least one selected from the group consisting of ether bond, amide bond and an imino bond), R ³ is May be the same or different and have 1 carbon atom
~ 8 unsubstituted or substituted divalent hydrocarbon groups, and Q is
Which may be the same or different, and is a monovalent alkyl ether group, Rf is a perfluoroalkyl group or a monovalent perfluoroalkyl ether group, and m is an integer of 1 to 3]. 0.1-15
Parts by weight , and (d) the following general formula (2): Wherein R ¹ , R ² , Rf and m are as described above, and 0.1 to 15 parts by weight of an alkoxysilane represented by the formula: