JPH0649826B2 - Room temperature curable composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a room temperature curable composition which is easily cured by the action of water.

(Prior Art) Conventionally, there is known a room-temperature-curable organopolysiloxane composition which is stably stored in a fluid state under a closed state and is cured at room temperature by the action of moisture in the air to become a rubber elastic body. This composition is widely used as a sealing material, a coating material, an adhesive, etc. in the construction industry field, the machine industry field, the electric industry field and the like.

(Problems to be Solved by the Invention) However, the above-mentioned conventional room temperature-curable organopolysiloxane composition has drawbacks that the rubber strength after curing is weak and the durability against an acidic compound and a basic compound is poor. Was there.

Therefore, it is an object of the present invention to provide a room temperature curable composition having high rubber strength after curing and excellent chemical resistance.

(Means for Achieving the Object) The room temperature curable composition of the present invention comprises (A) the following general formula [I], In the formula, R ^{1 to} R ⁴ each represent an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different from each other, n is an integer of 10 or more 100 parts by weight of organopolysilethylenesiloxane having both ends blocked with hydroxyl groups, and (B) from organosilane and organosiloxane having two or more hydrolyzable groups in one molecule At least one selected from the group consisting of 0.5 to 25 parts by weight is contained.

Component (A) In the present invention, the organopolysilethylenesiloxane used as the base component is represented by the above general formula [I], and as is clear from the general formula, both ends of the molecular chain are hydroxyl groups. It has been blocked.

In this general formula [I], each group of R ^{1 to} R ⁴ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms. Specifically, a lower alkyl group having 8 or less carbon atoms such as methyl group, ethyl group, propyl group, butyl group, cycloalkyl group such as cyclohexyl group, vinyl group, allyl group, propenyl group, butenyl group, etc. Alkyl, phenyl, tolyl, naphthyl, and other aryl groups, benzyl, 2-phenylethyl, and other aralkyl groups, and some or all of the hydrogen atoms in these groups are replaced with halogen atoms, cyano groups, etc. Group, for example, 2-cyanoethyl group, 3,3,3-trifluoropropyl group, 6,6,6,5,5,4,4,3,3-nonafluorohexyl group,
Examples thereof include a chloromethyl group and a 3-chloropropyl group. These R ^{1 to} R ⁴ groups may be the same or different groups.

In the general formula [I], n is an integer of 10 or more, usually
An integer of 10 to 5000, preferably an integer of 10 to 1000, and in connection with such a value of n, the organopolysilethylene siloxane used in the present invention has a viscosity at 25 ° C. of 25 to 1,000,000 cSt, It is preferably in the range of 1,000 to 100,000 cSt.

In the present invention, the organopolysilethylene siloxane which is particularly preferably used is as follows.

(However, n represents an integer of 10 to 5000.) Component (B) In the present invention, an organosilane having at least two hydrolyzable groups in one molecule is used in combination with the above organopolysilethylenesiloxane. Organosiloxane is used. That is, the hydrolyzable group serves as a reaction active point to cause a crosslinking reaction with the hydroxyl groups at both ends of the molecular chain of the organopolysilethylenesiloxane. Examples of such hydrolyzable groups include alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, methoxyethoxy group and ethoxyethoxy group;
Acyloxy groups such as acetoxy group, propionoxy group, butyroxy group; alkenyloxy groups such as propenyloxy group, isobutenyloxy group; dimethylketoxime group,
Iminoxy groups such as methylethylketoxime group, diethylketoxime group, cyclopentanoxime group, cyclohexanoxime group; N-methylamino group, N-ethylamino group, N-propylamino group, N-butylamino group, N, N-dimethylamino group, N, N-diethylamino group and other amino groups; N-
Examples thereof include amide groups such as methylacetamide group and N-ethylacetamide group; and aminooxy groups such as N, N-dimethylaminooxy group and N, N-diethylaminooxy group.

In addition to these hydrolyzable groups, as the substituent bonded to the silicon atom, R ¹ to R in the general formula [I] described above can be used.
An unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms similar to R ⁴ can be mentioned.

Specific examples of the above-mentioned organosilane and organosiloxane having at least two hydrolyzable groups include the following.

Examples of such organosilanes include alkoxysilanes such as methyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, tetraethoxysilane, tetraethoxysilane and the like. Partially hydrolyzed products; trioximosilanes such as methyltris (methylethylketoximo) silane, vinyltris (methylethylketoximo) silane; methyltriacetoxysilane, ethyltriacetoxysilane, phenyltriacetoxysilane, 6,6,6,5, Acetoxysilanes such as 5,4,4,3,3-nonafluorohexyltriacetoxysilane and tetraacetoxysilane; methyltriisopropenoxysilane,
Isopropenoes such as vinyltriisopropenoxysilane, phenyltriisopropenoxysilane, 6,6,6,5,5,4,4,3,3-nonafluorohexyltriisopropenoxysilane and tetraisopropenoxysilane Xysilane; Triaminosilane such as methyltris (diethylamino) silane and vinyltris (dicyclohexylamino) silane; Amidosilane such as methyltriethylacetamidosilane, phenyltrimethylacetamidosilane, vinyldiethylacetamidosilane; Methyltris (2,2,2-trifluoroethoxy) Examples thereof include trifluoroethoxysilane such as silane, vinyltris (2,2,2-trifluoroethoxy) silane, and tetrakis (2,2,2-trifluoroethoxy) silane.

Examples of the organosiloxane include 1,3,5,7-tetramethyl-1,3, -dipropyl-5,7-bis (diethylaminoxy) cyclotetrasiloxane and 1,3,5,7-tetramethyl- Examples thereof include aminoxysiloxanes such as 1-propyl-3,5,7-tris (diethylaminoxy) cyclotetrasiloxane.

In the present invention, among the above-mentioned organosilanes and organosiloxanes, in particular, vinyltriethoxysilane, tetraethoxysilane and partial hydrolysates thereof, methyltris (methylethylketoxime) silane, methyltriacetoxysilane, vinyltriisopropenoxy. Silane, 1,3,5,7-tetramethyl-1-propyl-3,
5,7-Tris (diethylaminoxy) cyclotetrasiloxane is preferably used.

These organosilanes and organosiloxanes have 1
They may be used alone or in combination of two or more. These are 0.5 to 25 parts by weight per 100 parts by weight of the organopolysilethylene siloxane of the component (A), and are used in a ratio of 1 to 10 parts by weight. Preferably. If the blending amount is less than the above range, gelation may occur during production or storage of the composition, or the obtained elastic body may not exhibit desired properties. Further, when the amount is more than the above range, the shrinkage ratio of the composition upon curing tends to be large, and the elasticity of the cured product tends to decrease.

Other compounding agents In addition, in the composition of the present invention, it is preferable to compound a curing catalyst in order to effectively carry out curing at room temperature in the presence of water. As the curing catalyst, those conventionally used for condensation-curing organopolysiloxane compositions can be used, for example, organic tin such as dibutyltin diacetate, dibutyltin octoate, dibutyltin dimethoxide, tin dioctoate. Examples thereof include compounds, titanium compounds such as tetraisopropoxy titanate, and guanidyl group-containing silanes such as tetramethylguanidylpropyltrimethoxysilane.

The curing catalyst is usually 5.0 per 100 parts by weight of component (A).
It is desirable that the amount is less than or equal to parts by weight, particularly 0.1 to 1.0 parts by weight. If it is blended in an excessively large amount, not only the film forming time becomes as short as several seconds and the workability is deteriorated, but also discoloration may occur during heating.

Further, in the composition of the present invention, conventionally used additives can be added to this type of composition as long as the object of the present invention such as improving the rubber strength after curing is not impaired. . For example, fumed silica, precipitated silica, carbon powder, titanium dioxide, aluminum oxide, quartz powder, talc, sericite, reinforcing agents such as bentonite, fibrous fillers such as asbestos, glass fiber, organic fiber, potassium methacrylate. Oil resistance improver such as, colorant, heat resistance improver such as red iron oxide and cerium oxide, cold resistance improver, thixotropic agent such as polyether, dehydrating agent, adhesion improver such as γ-aminopropyltriethoxysilane, A flame retardant improver such as a platinum compound may be appropriately blended, if necessary.

Room Temperature Curable Composition The room temperature curable 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. Alternatively, the component (A) and the component (B) may be packaged separately, and a two-pack type may be used in which they are mixed at the time of use.

When the composition of the present invention is exposed to air, the moisture in the air causes a crosslinking reaction to proceed and cure into a rubber elastic body. This rubber elastic body has high rubber strength and is also excellent in chemical resistance.

INDUSTRIAL APPLICABILITY The composition of the present invention is useful as a sealing material and a coating material in the construction and civil engineering industries, as well as an adhesive for electric and electronic parts, a sealant, a FIPG material in the automobile industry, and a gas represented by an oxygen-enriched film. It is also useful as a separation membrane.

(Examples) Hereinafter, the present invention will be described with reference to Examples. All parts in the examples are parts by weight, and the viscosity is a value measured at 25 ° C.

Example 1 The following formula, To 100 parts of silethylene siloxane polymer (viscosity 2500 cSt, specific gravity 0.915, n _D ²⁵ 1.4451), ethyl polysilicate-40 2.5 parts, (C ₄ H ₉ ) ₂ Sn (OCOC ₁₁ H ₂₃ ) ₂ 0.5 parts, Were mixed to prepare a composition I.

Using 2.0 parts of methyl silicate-51 in place of the ethyl silicate-40, a composition II was prepared in the same manner as above, and further using 3.0 parts of tetraisopropenoxysilane in place of the ethyl silicate-40. Composition III was prepared as described above.

After vacuum defoaming each of these compositions, the internal dimensions of 10 ^cm ×
It was injected into a mold of 10 ^cm × 0.20 ^cm and examined for curability at room temperature. As a result, after 16 hours of standing at room temperature, it was cured into a transparent elastic body.

This was further aged and cured at room temperature for 2 days, and the physical properties of the cured product were measured according to JIS K-6301. The measurement results are shown in Table 1.

Example 2 The following formula, Silethylene siloxane polymer represented by (viscosity 5750 cSt, specific gravity 0.912, n _D ²⁵ 1.4440), 100 parts, ethyl polysilicate-40 2.0 parts, (C ₄ H ₉ ) ₂ Sn (OCOC ₁₁ H ₂₃ ) ₂ 0.5 parts , Were mixed to prepare a composition IV.

After vacuum degassing this composition, the internal dimensions are 12 ^cm x 12 ^cm x 0.10 ^cm.
It was poured into a mold and cured at room temperature. The composition had a pot life of about 60 minutes and, after 16 hours, had cured into a transparent elastic body.

This was further aged and cured at room temperature for 6 days at room temperature, and the mechanical strength and electrical characteristics were measured.

For comparison, a similar composition V was prepared using dimethylpolysiloxane having a silanol at both ends and a viscosity of 5,000 cSt, and the mechanical strength and electrical properties were measured in the same manner. The measurement results are shown in Tables 2 and 3.

From this result, it is understood that the cured product formed from the composition of the present invention using the silethylene siloxane polymer has significantly higher strength than the cured product of dimethylpolysiloxane. Also, in terms of electrical characteristics, it is understood that the volume resistivity is 10 ³ times higher and the permittivity is about 10% lower.

Example 3 Silethylene siloxane polymer used in Example 2
100 parts Ethyl polysilicate-40 2.0 parts 20 parts of diatomaceous earth powder and 10 parts of calcium carbonate powder were mixed, and finally kneaded uniformly with a three-roll mill. The viscosity of this kneaded product was 15,500 centipoise.

Next, 100 parts of this kneaded product was mixed with water and an emulsion catalyst containing (C ₄ H ₉ ) ₂ Sn (OCOC ₁₁ H ₂₃ ) ₂ as a main component (Catalyst RM manufactured by Shin-Etsu Chemical Co., Ltd.).
0.5 part was added, uniformly mixed and defoamed under vacuum to obtain composition VI.

This was poured into a mold having inner dimensions of 14 ^cm × 17 ^cm × 0.20 ^cm and cured at room temperature. This composition had good fluidity (self-leveling property), had a pot life of about 40 minutes, and cured into an elastic body after 16 hours.

This was further aged and cured at room temperature for 2 days at room temperature, and the mechanical strength was measured as in Example 2.

For comparison, a similar composition VII was prepared using dimethylpolysiloxane having a silanol at both ends and a viscosity of 5,000 cSt, and the mechanical strength was measured in the same manner. Fourth measurement result
Shown in the table.

When a cured product sheet (2 ^cm × 2 ^cm ) of the above composition VI was immersed in a toluene solvent at room temperature for 3 days, the volume swelling ratio was 260%. Also, swell the sheet at room temperature x 24hr + 105
When the solvent was volatilized under the condition of ° C x 1 hr, the weight change was -1.0%, and it was found that the resin was cured well. When a similar test was performed on the composition VII, the volume swelling rate was 280% and the weight change was -1.5%.

Example 4 The following formula, After mixing 100 parts of silethylene siloxane polymer with a viscosity of 2,020 cSt and 12 parts of fumed silica whose surface is treated with hexamethylsilazane (specific surface area 150 m ² / g), after passing through 3 rolls once , With this, methyltriisopropenoxysilane 6 parts Composition VIII was obtained by defoaming and mixing 0.5 part of a guanidyl group-containing silane represented by

This composition VIII was formed into a sheet having a thickness of 2 mm and the temperature was 20
When left for 7 days in an atmosphere of ℃ and 55% relative humidity,
This sheet was cured into a rubber elastic body.

Further, this composition VIII was stable at room temperature for 6 months or more in a sealed state. After the lapse of 6 months, composition VIII having a thickness of 2
The sheet was molded into a sheet of mm and cured under the same conditions as above to obtain a rubber elastic body.

The rubber physical properties of the rubber elastic body obtained from the composition in the initial state and the rubber elastic body obtained from the composition after standing for 6 months were measured by JI
When measured according to S C-2123, the results shown in Table 5 were obtained.

Further, the rubber elastic body obtained from the composition in the initial state was immersed in concentrated sulfuric acid and a 20% sodium hydroxide aqueous solution at 20 ° C. for 72 hours, and then the rubber physical properties were measured according to JIS C-2123. However, the results shown in Table 6 were obtained.

Example 5 The following formula, 100 parts of silethylene siloxane polymer with a viscosity of 4,870 cSt and 15 parts of sericite were mixed and passed through a 3-roll once, and then defoamed with 0.1 parts of ethyl polysilicate and 0.1 part of dibutyltin dioctoate. Mixing gave composition IX.

This composition VIII was formed into a sheet having a thickness of 2 mm and the temperature was 20
When left in an atmosphere of ℃ and 55% relative humidity for 3 days,
This sheet was cured into a rubber elastic body.

The rubber physical properties of this rubber elastic body were measured according to JIS C-2123, and the results shown in Table 7 were obtained.

Example 6 The following formula, After mixing 100 parts of silethylene siloxane polymer with a viscosity of 20,500 cSt and 10 parts of fumed silica whose surface is treated with dimethyldichlorosilane (specific surface area 120 m ² / g) and passing it through a 3-roll roll once Then, a composition X was obtained by degassing and mixing 6 parts of vinyltriacetoxysilane with 0.1 part of dibutyltin diacetate under anhydrous conditions.

This composition X was molded into a sheet having a thickness of 2 mm, and the temperature was 20 ° C.
When left for 7 days in an atmosphere with a relative humidity of 55%, the sheet cured to become a rubber elastic body.

Moreover, this composition X was stable at room temperature for 6 months or more in a sealed state. The composition VIII after 6 months has a thickness of 2 mm.
Was molded into a sheet and cured under the same conditions as above to obtain a rubber elastic body.

The rubber physical properties of the rubber elastic body obtained from the composition in the initial state and the rubber elastic body obtained from the composition after standing for 6 months were measured by JI
When measured according to S C-2123, the results shown in Table 8 were obtained.

Example 7 The following formula, After mixing 100 parts of silethylene siloxane polymer with a viscosity of 11,300 cSt with 10 parts of fumed silica whose surface is treated with dimethyldichlorosilane (specific surface area 120 m ² / g), and passing it through a three-roll once Then, vinyltrismethylethyl (ketoximo) silane 8 parts Dibutyltin diacetate 0.1 part was degassed and mixed under anhydrous conditions to obtain a composition XI.

This composition XI is formed into a sheet having a thickness of 2 mm, and the temperature is 20 ° C.
When left for 7 days in an atmosphere with a relative humidity of 55%, the sheet cured to become a rubber elastic body.

Further, this composition XI was stable at room temperature for 6 months or more in a sealed state. After 6 months, the composition XI was molded 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 physical properties of the rubber elastic body obtained from the composition in the initial state and the rubber elastic body obtained from the composition after standing for 6 months were measured by JI
When measured according to S C-2123, the results shown in Table 9 were obtained.

(Effects of the Invention) According to the present invention, a room-temperature curable composition capable of forming a cured product having high rubber strength after curing and excellent resistance to acids, alkalis and the like can be obtained.

Front page continuation (72) Inventor Hirofumi Kinoshita 2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Shinichi Sato 2 Isobe, Annaka-shi, Gunma 13-1 1-1 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Sai Minami 2-13-1 Isobe, Annaka City, Gunma Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Koichi Yamaguchi 2-13-1, Isobe, Annaka City, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Takatoshi Matsuda 2-13, Isobe, Gunma Prefecture No. 1 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (1)

[Claims] (A) The following general formula [I], In the formula, R ^{1 to} R ⁴ each represent an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different from each other, n is an integer of 10 or more 100 parts by weight of organopolysilethylenesiloxane having both ends blocked with hydroxyl groups, and (B) consisting of an organosilane and an organosiloxane having two or more hydrolyzable groups in one molecule. A room temperature curable composition comprising 0.5 to 25 parts by weight of at least one selected from the group.