JP2819371B2 - Room temperature curable organopolysiloxane composition and cured product thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room temperature curable organopolysiloxane composition which is easily cured by the action of moisture and a cured product thereof, and particularly when used outdoors, contaminates its surface or its surroundings. In addition, the present invention relates to a composition which can be easily removed even if mold is generated on the surface, and a cured product thereof.

[0002]

2. Description of the Related Art Conventionally, so-called room-temperature-curable organopolysiloxanes which are stably stored in a hermetic state while maintaining their fluidity under airtight conditions, but are cured at room temperature by the action of moisture in the atmosphere to form a rubbery elastic material. Compositions are known and are widely used as sealants, coatings, and adhesives in the construction, mechanical, or electrical industries.

[0003] However, these room temperature curable organopolysiloxane compositions have the drawback that when used as a sealing material or a coating material, their surfaces and surroundings are contaminated and the appearance of the building is easily impaired. In order to reduce or prevent this contamination, various additives have been studied. For example, a method using a surfactant having a polyoxyethylene group, a sorbitan residue or a disaccharide residue (Japanese Patent Application Laid-Open No. 56-76)
452, JP-A-56-76453), a method using a surfactant having at least one fluorine atom in the molecule (see JP-A-58-167647), and an interface having at least one fluorine atom in the molecule. A method using a combination of an activator and an organosilicon compound having an amino group (see Japanese Patent Application Laid-Open No. 61-34062) is known. It was almost ineffective.

A cured elastic material obtained from a conventionally known room-temperature-curable organopolysiloxane composition has an aesthetic appearance at the beginning of construction. However, when it is applied to a bathroom, a kitchen, a washroom or the like, it has various effects. There is a drawback that contamination is likely to be caused by foreign matter (such as a residue, detergent, food, etc.), and when the humidity is high, mold is generated and the appearance is easily impaired.

[0005]

Therefore, in order to impart mold resistance, JP-A-54-43260 discloses the addition of a benzimidazolyl-alkyl-carbamate to a moisture-curable room temperature-curable organopolysiloxane composition. Disclosure,
JP-A-57-18758 discloses the addition of an organosilicon compound having a tetraorganoguanidyl group.

However, it is difficult to maintain the fungicide-preserving composition for a long period of time because the fungicide flows out of water with these fungicidal compositions.

[0007] Therefore, the object of the present invention is to solve the above disadvantages, especially when used outdoors.
It is an object of the present invention to provide a composition and a cured product thereof that do not contaminate the surface of the cured product and its surroundings and that can easily be removed even if mold is generated on the surface.

[0008]

In order to solve the above-mentioned problems, the present invention provides (A) 100 parts by weight of a diorganopolysiloxane in which both ends of a molecular chain are blocked with hydroxyl groups, and (B) silicon in one molecule. Organosilicon compound having at least three hydrolyzable groups bonded to atoms or partial hydrolyzate thereof 0.5 to 30
Parts by weight, and (C) general formula (1):

Embedded image (Wherein R ¹ and R ² are unsubstituted or substituted carbon atoms of 1
And R ³ is an amide bond (—CON
H-) or 1 carbon atom which may contain etheric oxygen
And Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, and n is an integer of 1 to 3). And a room temperature curable organopolysiloxane composition comprising:

Further, the present invention provides a cured product obtained by curing the above composition.

Component (A) The diorganopolysiloxane in which both ends of the molecular chain are blocked with hydroxyl groups as the component (A) is represented by the general formula (2):

Embedded image (Wherein R ′ and R ″ are alkyl groups such as methyl group, ethyl group and propyl group, cycloalkyl groups such as cyclohexyl group, alkenyl groups such as vinyl group and allyl group, and aryl groups such as phenyl group and tolyl group. Or a group in which a hydrogen atom of these groups is partially substituted with a halogen atom or the like, and R ′ and R ″ may be the same or different groups; n is an integer of 10 or more; Preferably, the viscosity at 25 ° C. of the diorganopolysiloxane is 25 to 500,000 cS
It is an integer in the range of t, more preferably in the range of 1000 to 100,000 cSt. ).

Component (B) The organosilicon compound having at least three hydrolyzable groups bonded to a silicon atom in one molecule constituting the component (B) of the composition of the present invention, and the partially hydrolyzed product thereof, It is an essential component for the composition of the invention to cure at room temperature in the presence of moisture (moisture). As the hydrolyzable group, an alkoxy group, a ketoxime group, an acyloxy group, an amino group,
Examples thereof include an amide group, an aminoxy group and an alkenyloxy group. The organosilicon compound may be either a silane or a siloxane compound, and specific examples thereof include the following compounds.

Alkoxysilanes such as methyltrimethoxysilane, vinyltriethoxysilane, 3-chloropropyltrimethoxysilane and 3-aminopropyltriethoxysilane, methyltris (dimethylketoxime)
Silane, ketoxime silane such as methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane, tetra (methylethylketoxime) silane, acyloxysilane such as vinyltriacetoxysilane, methyltriacetoxysilane, phenyltriacetoxysilane, phenyltris ( N-
Amidosilanes such as methylacetamide) silane and vinyltris (N-methylacetamido) silane; aminosilanes such as vinyltris (N-butylamino) silane and phenyltris (N, N-diethylamino) silane; methyltris (N, N-dimethylaminoxy) Silanes, aminooxysilanes such as vinyltris (N, N-diethylaminoxy) silane, alkenyloxysilanes such as vinyltriisopropenoxysilane, methyltriisobutenoxysilane, phenyltricyclohexanoxysilane, and one or two kinds thereof The above partial hydrolyzate. These organosilicon compounds and partial hydrolysates thereof can be used alone or in combination of two or more.

The amount of the component (B) must be set to 0.5 to 30 parts by weight per 100 parts by weight of the component (A). Ingredient (B)
When the amount of the compound is less than 0.5 part by weight, there is a disadvantage that gelation occurs during the production or storage of the composition, and the desired physical properties are not exhibited in the obtained elastic body.
On the other hand, when the amount is more than 30 parts by weight, the shrinkage of the composition at the time of curing becomes excessive, and the elasticity of the cured product also decreases. More preferably, the amount of component (B) is from 3 to 15 parts by weight.

Component (C) The alkoxysilane of the above general formula (1) constituting the component (C) of the composition of the present invention acts as a surface coating agent.

General formula (1):

Embedded image In the above, the substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms represented by R ¹ and R ² is, for example,
Alkyl groups such as methyl group, ethyl group and propyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; alkenyl groups such as vinyl group and allyl group; aryl groups such as phenyl group and tolyl group; or hydrogen atoms of these groups Is a group partially substituted with a halogen atom or the like. The divalent hydrocarbon group represented by R ³ is, for example, an alkylene group such as a methylene group, an ethylene group or a propylene group, a cycloalkylene group such as a cyclopentylene group or a cyclohexylene group, or an arylene group such as a phenylene group. , —R ⁴ OR ⁵ —, or —R ⁴ CONH R ⁵ — (where R ⁴ and R ⁵ may be the same or different and include an alkylene group such as a methylene group, an ethylene group, a propylene group, a cyclopentylene A cycloalkylene group such as a cyclohexylene group, or an arylene group such as a phenylene group.).

In the general formula (1), Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group. Specifically, for example, general formula (3):

Embedded image

(Wherein, e and i may be the same or different and are 0 or 1, f and h may be the same or different and are integers of 0 to 30, and g is an integer of 0 to 8) However,
The above e, f, g, h and i are (e + f + g + h +
i) It is an integer of ≧ 1. Further, the plurality of Y is a group represented by well-fluorine atom or -CF ₃ be the same or different. A group represented by the general formula (4):

[0018]

Embedded image

Wherein m is an integer of 0 to 10, and n is 2
It is an integer of ~ 50. Further, the plurality of X is a group represented by well-fluorine atom or -CF ₃ be the same or different. ), And a general formula (5):

[0020]

Embedded image (In the formula, k is an integer of 1 to 100.)

As a typical example of the above Rf,

Embedded image And the like.

Specific examples of the compound represented by the above general formula (1) include the following.

[0023]

Embedded image

Component (C) is used with respect to 100 parts by weight of component (A).
0.1 to 15 parts by weight, preferably 0.5 to 5 parts by weight. If this component (C) is less than 0.1 part by weight, a sufficient coating layer is not formed on the surface of the cured rubber, and
If the amount is more than 15 parts by weight, the physical properties of the obtained rubber-like elastic body are reduced, and it is economically disadvantageous.

Preparation of Composition The composition of the present invention can be obtained as a one-part, room temperature curable composition by uniformly mixing predetermined amounts of the above-mentioned components (A) to (C) in a dry atmosphere. The homogeneous mixture of the component (A) and the component (C) and the component (B) may be separately packaged, and may be a two-pack type in which these are mixed at the time of use.

When this composition is exposed to the air, the crosslinking reaction proceeds due to the moisture in the air, and the composition cures to a rubber-like elastic body. This includes a known catalyst which promotes this kind of reaction, for example, an amine. Compounds, quaternary ammonium salts, organometallic compounds, titanium chelate compounds, guanidyl group-containing compounds, and the like may be added. In addition, inorganic fillers for adjusting the physical properties of the rubber-like elastic material of interest, for example, reinforcement of known powder fillers such as fumed silica, precipitated silica, titanium dioxide, aluminum oxide, quartz powder, talc and bentonite Agents, asbestos, fibrous fillers such as glass fibers and organic fibers, oil-resistance improvers such as potassium methacrylate, coloring agents, heat-resistance improvers such as red iron oxide and cerium oxide, cold-resistance improvers, thixotropes such as polyethers , A dehydrating agent, an adhesion improver such as γ-aminopropyltriethoxysilane, and the like may be added, and these may be added in predetermined amounts as necessary.

Applications The composition is non-staining and can easily remove mold and the like, so that it can be used as a sealing material for building exteriors, a coating material or a sealing material for places where mold is likely to occur, such as bathrooms and kitchens. It is useful for coating materials and the like.

[0028]

The above-mentioned components (A) and (B) are known as components of a room-temperature-curable silicone rubber composition. The composition of the present invention comprises a hydroxyl group in component (A) and a component (B). It becomes a rubber-like elastic body by condensation with the hydrolyzable group in it.

Due to the action of the component (C), the composition of the present invention does not contaminate the surface and surroundings of the cured product when used as a sealing material or a coating material, and has a ventilation property such as a bathroom, kitchen or washroom. Even when used in an environment that is inferior in properties, high in humidity, easily contaminated by foreign substances such as scales, detergents or foods, and mold is likely to occur, the generated mold can be easily removed.

[0030]

EXAMPLES Examples of the present invention will be described below. All parts in the examples are parts by weight, and the viscosities are values measured at 25 ° C.

Examples 1 to 3; Comparative Example 1 100 parts of dimethylpolysiloxane having both ends of a molecular chain having a viscosity of 20200 cSt and capped with hydroxyl groups, and the surface thereof was treated with hexamethyldisilazane to give a specific surface area of 150 m ² / g. Was mixed with 12 parts of fumed silica and 1.5 parts of titanium dioxide. After passing the resulting mixture through a three-roll mill once,
Further, 7 parts of methyltributanoxime silane and 0.1 part of dibutyltin dioctoate were defoamed and mixed in an anhydrous state to obtain a composition I.

Next, the above-mentioned composition I has the following structural formula:

Embedded image 1.0 part of perfluoropolyether silane represented by
3.0 parts and 5.0 parts were added, respectively, to the composition II,
Composition III and composition IV were obtained.

Mechanical properties The above compositions I, II, III and IV were each prepared with a thickness of 2 mm.
When the sheet was left in an atmosphere at a temperature of 20 ° C. and a relative humidity of 55% for 7 days, each sheet was cured to become a rubber-like elastic body. In addition, the above compositions I, II, III and IV
Is stable at room temperature for 6 months or more in a sealed state. After the lapse of 6 months, each of the compositions I, II, III and IV has a thickness of 2
Each sheet was formed into a rubber-like elastic body when molded into a sheet of mm and cured under the same conditions as above. The rubber properties obtained by molding and curing each of the compositions at the initial stage and after the lapse of 6 months were measured for rubber properties, respectively.
It was measured according to the method of JIS C 2123. The results are shown in Tables 1 and 2.

[0034]

[Table 1]

[0035]

[Table 2]

Adhesiveness Next, as shown in FIG. 1, a sealing material 2 composed of the above-described composition I was applied to an end of one surface of an adherend 1 having a size of 100 × 25 × 10 mm in an area of 25 × 10 mm. Is applied, and a Teflon plate having a thickness of 1 mm is placed as spacers 3 and 3 'at positions sandwiching the sealing material. Then, the same adherend 1' as described above is stacked thereon, and a 500 g weight 4 is attached. I put it. In this state, the sealing material was cured by leaving it in an atmosphere of 20 ° C. and 55% RH for 7 days to prepare a test body. Test pieces were prepared for compositions II, III and IV in the same manner as for composition I described above. As the above-mentioned adherend 1, those made of glass, aluminum, iron and epoxy resin were used. About the obtained test body, the shear adhesive force was measured by pulling both ends of each test body in the opposite direction. Table 3 shows the results.

[0037]

[Table 3]

[0038] using a contact angle Kyowa Interface Science Co., Ltd. contact angle meter, composition I,
The contact angles of pure water and silicone oil (10 cSt) on the cured sheets II, III and IV were measured, respectively. Table 4 shows the results.

[0039]

[Table 4]

Stain resistance Two square granites 15 mm thick (dimensions 300 × 300
× 15 mm) was placed on a flat base with the square face down so that one end face of each 300 × 15 mm was parallel, and the composition I was placed in a 15 mm gap formed between both end faces. I
After filling with I, III and IV respectively (filling size 300 × 1
The composition was cured to form a test body.

The test specimen obtained above was allowed to stand outdoors for 3 months, 6 months, and 12 months, and the state of generation of stains on the surface of the cured product and its surroundings was examined. Table 5 shows the results.

[0042]

[Table 5] A: No dirt is observed B: Slight dirt is generated C: Dirt is considerably generated

Compositions I, II and III prepared in the same manner as in the mold resistance test
Each of the cured sheets IV and IV was punched into a circle having a diameter of 30 mm, and the mold resistance was measured in accordance with JIS Z 2911 “Testing method for mold resistance”. Further, the removability of the mold adhered to the back surface of each cured sheet was evaluated. Table 6 shows the results.

[0044]

[Table 6] Note: Evaluation criteria for mold resistance:-: No mold was generated on the test piece. +: Mold was generated on the test piece in an area of 1/3 or less. Evaluation criteria for mold removability: A cured sheet with mold was attached to tissue. Wipe off with paper. A: Easily removable: Almost removable by wiping once B: Removable: Removable by wiping several times C: Removal difficult: Cannot be removed even by wiping several times

Examples 4 to 6, Comparative Example 2 100 parts of dimethylpolysiloxane having a viscosity of 20500 cSt and both ends of a molecular chain blocked with hydroxyl groups were treated with hexamethyldisilazane on the surface, and the specific surface area was 150 m ² / g. Was mixed with 12 parts of fumed silica and 1.5 parts of titanium dioxide.
After passing the resulting mixture through three rolls once, the mixture was further charged with 6 parts of vinyltriisopropenoxysilane and the following structural formula:

Embedded image A composition V was obtained by defoaming and mixing 0.5 part of a guanidyl-containing silane represented by the following formula in an anhydrous state.

Next, the above composition V is added to the following structural formula:

Embedded image 1.0 part of perfluoropolyether silane represented by
3.0 parts and 5.0 parts were added, respectively, to the composition VI,
Composition VII and composition VIII.

Mechanical properties The compositions V, VI, VII and VIII described above were each coated with a thickness of 2
When the sheet was molded into a sheet having a thickness of 20 mm and left for 7 days in an atmosphere at a temperature of 20 ° C. and a relative humidity of 55%, each sheet was cured to become a rubber-like elastic body. Also, the compositions V, VI, VII and
VIII is stable for at least 6 months at room temperature in a sealed state. After 6 months, the compositions V, VI, VII and VIII are formed into sheets each having a thickness of 2 mm and cured under the same conditions as above. As a result, each sheet was cured to become a rubber-like elastic body. The rubber properties of the rubber-like elastic material obtained by molding and curing each composition at the initial stage and after 6 months had been measured according to the method of JIS C 2123. The results are shown in Tables 7 and 8.

[0048]

[Table 7]

[0049]

[Table 8]

Adhesion In the same manner as in Example 1, a test specimen as shown in FIG. 1 was prepared for each composition, and the shear adhesion of the test specimen whose coating surface was cured under the same conditions was measured. Table 9 shows the results.

[0051]

[Table 9]

Contact Angle Compositions V and V were measured using a contact angle meter manufactured by Kyowa Interface Science Co., Ltd.
The contact angles of pure water and silicone oil (10 cSt) on the cured sheets of I, VII and VIII were measured respectively. Table 10 shows the results.

[0053]

[Table 10]

[0054] two square in stain resistance thickness 15mm granite (dimensions 300 × 300
X 15 mm) on a flat base with the square surface facing down so that one end surface of each 300 x 15 mm is parallel, and the composition V is placed in a 15 mm gap formed between both end surfaces. ,
After filling VI, VII and VIII respectively (filling size 300
× 300 × 15 mm), and the composition was cured to prepare a test body.

The test specimen obtained above was allowed to stand outdoors for 3 months, 6 months, and 12 months, and the condition of stain generation on the surface of the cured product and its surroundings was examined. Table 11 shows the results.

[0056]

[Table 11] A: No dirt is observed B: Slight dirt is generated C: Dirt is considerably generated

The cured sheets of the mold-resistant compositions V, VI, VII and VIII were each punched into a circle having a diameter of 30 mm, and the mold resistance was measured according to JIS Z 2911 "Mold resistance test method". In addition, the removability of mold adhered to the back surface of each cured sheet was evaluated in Example 1.
The measurement was performed in the same manner as described above. Table 12 shows the results.

[0058]

[Table 12] Note: Evaluation criteria for mold resistance:-: No mold was generated on the test piece. +: Mold was generated on the test piece in an area of 1/3 or less. Evaluation criteria for mold removability: A cured sheet with mold was attached to tissue. Wipe off with paper. A: Easily removable: Almost removable by wiping once B: Removable: Removable by wiping several times C: Removal difficult: Cannot be removed even by wiping several times

Examples 7 to 9 and Comparative Example 3 100 parts of dimethylpolysiloxane having a viscosity of 21200 cSt and both ends of a molecular chain blocked by a hydroxyl group were treated with hexamethyldisilazane on the surface to give a specific surface area of 120 m ² / g. Was mixed with 12 parts of fumed silica and 1.5 parts of titanium dioxide.
The resulting mixture was passed once through a three-roll mill, and 7 parts of methyltributanoxime silane and 0.1 part of dibutyltin dioctoate were defoamed and mixed in an anhydrous state to obtain a composition A.

Next, this composition A is added to the following formula:

Embedded image 3 parts of the perfluoropolyether silane represented by the following formulas were added to obtain composition IX, composition X, composition XI, and composition XII.

Using the above compositions IX, X, XI and XII, an outdoor exposure test and a mold resistance test were carried out in the same manner as in Example 1. The results are shown in Tables 13 and 14.

[0062]

[Table 13] A: No dirt is observed B: Slight dirt is generated C: Dirt is considerably generated

[0063]

[Table 14] -: No mold on the test piece A:
Can be easily removed +: Mold is generated on the test piece in an area of 1/3 or less B:
Removable C: Difficult to remove

[0064]

According to the present invention, for example, when used as a sealing material or a coating material, the surface and surrounding contamination can be significantly reduced. In addition, even if used in an environment where the air permeability is poor, such as bathrooms, kitchens, or washrooms, where the humidity is high, and which is easily contaminated by foreign substances such as people, detergents, foods, etc., and mold tends to occur. In addition, the generated mold can be easily removed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a specimen used for measuring a shear adhesive force in Examples.

Continuing on the front page (72) Inventor, Hitoshi Kinan 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Hirokazu Yamada, Matsuda-cho, Inui-gun, Gunma Prefecture Hitomi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 83/06 C08K 5/54 C09D 183/06 C09J 183/06

Claims (2)

(57) [Claims] 1. An organosilicon compound having (A) 100 parts by weight of a diorganopolysiloxane in which both ends of a molecular chain are blocked with a hydroxyl group, and (B) at least three hydrolyzable groups bonded to silicon atoms in one molecule. Or 0.5 to 30 parts by weight of a partial hydrolyzate thereof, and (C) a general formula (1): (Wherein R ¹ and R ² are unsubstituted or substituted carbon atoms of 1
And R ³ is an amide bond (—CON
H-) or 1 carbon atom which may contain etheric oxygen
And Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, and n is an integer of 1 to 3). A room temperature curable organopolysiloxane composition comprising: 2. A cured product obtained by curing the composition according to claim 1.