JP2974231B2 - Room temperature curable organopolysiloxane compositions with extended pot life - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-part room temperature-curable organopolysiloxane composition which cures at room temperature into a rubber elastic body and a cured product thereof, and more particularly to a building used for joints of a building. The present invention relates to a two-part room-temperature-curable organopolysiloxane composition useful as a sealing material for use and a cured product thereof.

[0002]

2. Description of the Related Art A room temperature-curable organopolysiloxane composition which cures at room temperature to form a rubber elastic material has excellent properties such as durability, weather resistance, heat resistance, and cold resistance. Although widely used in various fields, it is frequently used as an adhesive or a sealing material particularly in the field of building materials.

A two-part room temperature curable organopolysiloxane composition comprises a base component and a curing agent component, and is cured by mixing these components when used.
In a construction site where the above composition is actually used as a building sealing material, first, one can of the base component (usually 3 to
(4 L / can) and the curing agent component are mechanically mixed at an appropriate mixing ratio. Then use the resulting mixture for building components,
It may take about 2 to 5 hours to use for the building member. During this time, the mixture must be maintained at a usable viscosity. The time that must be maintained at this usable viscosity is called the pot life. The pot life depends on the curing speed and becomes shorter as the temperature becomes higher. Therefore, especially in a high temperature period such as summer, the pot life is usually extended by increasing the amount of the curing agent.

[0004]

As the above-mentioned curing agent, a nitrogen-containing organosilicon compound having a substituted aminoxy group bonded to a silicon atom is generally used. However, since the nitrogen-containing organosilicon compound is a curing agent (crosslinking agent), if the amount of addition is large, the physical properties of the sealing material itself after curing change, so that the amount of addition cannot be increased, so Time cannot be extended. Further, the above-mentioned nitrogen-containing organosilicon compound is expensive and therefore economically disadvantageous.

Accordingly, an object of the present invention is to provide a two-part room temperature curable organopolysiloxane capable of extending the pot life at 5 to 50 ° C. for about 1 to 10 hours without changing the physical properties of the obtained cured product. An object of the present invention is to provide a composition and a cured product thereof.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have solved the above problems. The present invention relates to (A) a diorganopolysiloxane having hydroxyl groups at both molecular chain terminals.
100 parts by weight, (B) a compound containing, on average, more than 2.0 substituted aminoxy groups bonded to a silicon atom in one molecule, wherein the substituted aminoxy groups have the general formula (1):

Embedded image (Wherein R ¹ and R ² may be the same or different and are monovalent hydrocarbon groups), and a general formula (2):

Embedded image (Wherein, R ³ is a divalent organic group) 0.1 to 30 parts by weight of a nitrogen-containing organosilicon compound selected from the group consisting of groups represented by the following formula: (C) calcium carbonate
1 to 200 parts by weight, and (D) general formula (3):

Embedded image (Where n is an integer of 3 to 10), and a general formula (4):

Embedded image (Wherein m is an integer of 0 to 8), and the pot life including at least 1 to 50 parts by weight of at least one selected from the group consisting of linear organopolysiloxanes represented by the formula (1) is extended. Room temperature curable organopolysiloxane composition, and a cured product thereof.

(A) Component The diorganopolysiloxane having hydroxyl groups at both molecular chain terminals of the component (A) is a base component of the composition of the present invention,
It has been conventionally used as a main raw material of silicone rubber. The component (A) is, for example, an average composition formula (5): (R ⁴ ) _a SiO _{(4-a) / 2} (5) (wherein R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group, a is a number from 1.09 to 2.05), which is a diorganopolysiloxane having hydroxyl groups at both molecular chain terminals.

R ⁴ in the formula is a substituted or unsubstituted monovalent hydrocarbon group, preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. Specifically, methyl group, ethyl group, alkyl group such as propyl group, vinyl group,
Examples thereof include an alkenyl group such as an allyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, and those in which a hydrogen atom of these groups is partially substituted with a halogen atom, a cyano group, or the like.

The viscosity of the component (A) at 25 ° C. is determined so that the cured product obtained by curing the composition of the present invention exhibits good rubber elasticity and also has excellent mechanical strength. Usually, it is preferably 300 cP or more, and
It is preferably at least 00 cP. There is no particular upper limit on the viscosity of the component (A) at 25 ° C., but when the composition of the present invention is used as a building sealing material, it is required to have a certain degree of fluidity. It is preferable that the pressure be less than 50,000 cP.

Component (B) The nitrogen-containing organosilicon compound of component (B) is a compound containing, on average, more than 2.0 substituted aminoxy groups bonded to silicon atoms in one molecule. The substituted aminoxy group is at least one selected from the group consisting of groups represented by the general formulas (1) and (2).

In the general formula (1), R ¹ and R ² may be the same or different and are each a monovalent hydrocarbon group, preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms. Specific examples include an alkyl group such as a methyl group, an ethyl group, and a propyl group, a phenyl group, and an aralkyl group.

In the general formula (2), R ³ is 2
Organic group, specifically,

Embedded image Etc. are exemplified.

The component (B) is a so-called curing agent (crosslinking agent), which reacts with the hydroxyl group of the component (A) to release the hydroxyamino compound XOH (where X is as defined above) and is cured. (Crosslinking) Initiate a reaction.

The nitrogen-containing organosilicon compound as the component (B) must contain on average more than 2.0 of the above-mentioned substituted aminoxy groups bonded to silicon atoms in one molecule.
Thereby, a cured product excellent in rubber elasticity is obtained. Therefore, when a nitrogen-containing organosilicon compound containing on average 2.0 or less substituted aminoxy groups bonded to a silicon atom in one molecule is used, for example, one substituted aminoxy group is used.
When only a compound having two in the molecule is used, crosslinking is insufficient, and a cured product having excellent rubber elasticity cannot be obtained. However, even when a nitrogen-containing organosilicon compound having two substituted aminoxy groups in one molecule, the substituted aminoxy group is used in combination with a nitrogen-containing organosilicon compound having three or more substituted aminoxy groups in one molecule. On average in one molecule
If the content is more than 2.0, it can be used.

The component (B) is, for example, a compound represented by the following general formula (6):

Embedded image (In the formula, R ⁵ is a substituted or unsubstituted monovalent hydrocarbon group, preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms.
Is a multivalent hydrocarbon group. When a plurality of R ⁵ are present, they may be the same or different. X represents the general formula (1) and
A substituted aminoxy group selected from the group consisting of groups represented by (2), and when there are a plurality of Xs, they may be the same or different. b is an integer of 0 to 2;
It is an integer of 10. ).

However, when a compound of b = 2 among the compounds represented by the general formula (6) is used, a nitrogen-containing organosilicon compound containing three or more substituted aminoxy groups in one molecule. Use with

As the compound represented by the above general formula (6), specifically,

Embedded image Etc. are exemplified.

Further, as the component (B), for example,
(7): —OSi (X) (R ⁵ ) — (7) (wherein R ⁵ and X are as defined above), and a substituted or substituted aminoxy group-containing cyclic or linear organo group containing a unit represented by formula Polysiloxanes can also be used. However, when a nitrogen-containing organosilicon compound containing two substituted aminoxy in one molecule is used among such cyclic and linear organopolysiloxanes, the substituted aminoxy group is contained in three molecules in one molecule.
Used together with at least one nitrogen-containing organosilicon compound.

As the compound containing the unit represented by the above general formula (7), specifically,

Embedded image Etc. are exemplified.

Further, in order for the component (B) to exert its effect as a crosslinking agent sufficiently, it is necessary to use 100 parts by weight of the component (A)
Component (B) must be present in an amount of 0.1 to 30 parts by weight, preferably 1 to 10 parts by weight. When the amount of the component (B) is less than 0.1 part by weight, crosslinking is insufficient, and when the amount exceeds 30 parts by weight, not only takes a very long time to cure, but also there is a possibility that the rubber layer once cured may be deteriorated. Is inconvenient.

(C) Component The calcium carbonate of the component (C) is a reinforcing agent and a bulking agent. The amount of the component (C) is based on 100 parts by weight of the component (A).
The range is from 1 to 200 parts by weight, preferably from 10 to 100 parts by weight.

Component (D) The component (D) is selected from the group consisting of a cyclic organopolysiloxane represented by the general formula (3) and a linear organopolysiloxane represented by the general formula (4). At least one type. The present inventors have found that the pot life can be extended by adding the component (D) to the room temperature curable composition comprising the components (A) to (C), and completed the present invention. Although the reason is not clear, it is presumed that after mixing the components (A) to (D), the component (D) is vaporized to prevent water from entering the sealant. The component (D) can be used alone or as a mixture of two or more.

The amount of component (D) is from 1 to 50 parts by weight, preferably from 1 to 10 parts by weight, per 100 parts by weight of component (A). . If the amount of the component (D) is less than 1 part by weight, the pot life cannot be extended, and if it exceeds 50 parts by weight, slumps occur at vertical joints during construction.

Other Additives The composition of the present invention may optionally contain other fillers, for example, crystalline silica fine powder, amorphous silica fine powder, silica hydrogel, silica aerogel, Examples include diatomaceous earth, calcium silicate, aluminum silicate, titanium oxide, aluminum oxide, zinc oxide, iron oxide, carbon black, graphite, mica, clay, bentonite, and the like. Incidentally, the composition of the present invention, a pigment,
The addition of various additives such as a heat resistance improver and a flame retardant is optional as long as the object of the present invention is not impaired.

Room- Temperature-Curable Organopolysiloxane Composition The room-temperature-curable composition of the present invention comprises, for example, the above (A)
A two-part room temperature curable composition is prepared as a main agent containing a predetermined amount of component (C) and a curing agent containing predetermined amounts of components (B) and (D). By mixing the main agent and the curing agent in the atmosphere at the time of use, a crosslinking reaction by condensation proceeds, and a cured product is formed.

[0026]

Embodiments of the present invention will be described below. In the following Examples and Comparative Examples, all parts are parts by weight. Example 1 50 parts of dimethylpolysiloxane having hydroxyl groups at both ends of a molecular chain (viscosity at 25 ° C .: 5000 cp) and calcium carbonate
50 parts were kneaded with three rolls to obtain a non-flowable paste-like mixture. In 100 parts of this paste-like mixture, formula (8):

Embedded image 2.375 parts of a compound represented by the following formula (9):

Embedded image A mixture with 0.125 part of a compound represented by the formula:

Embedded image Was added and mixed by stirring.

The working life of the obtained mixture at 20 ° C. was measured in accordance with JIS A 5758. Table 1 shows the results.

After defoaming the obtained mixture under reduced pressure, the mixture was put in a rectangular frame having a thickness of 2 mm, evacuated again, and cured at 20 ° C. and 55% RH for 7 days. The hardness, elongation and tensile strength of the obtained sheet-shaped cured product were measured according to JIS K6301. Table 1 shows the results.

Example 2 A mixture was obtained in the same manner as in Example 1 except that 5 parts of the cyclic organopolysiloxane represented by the formula (10) was added. Pot life at 20 ° C. of the obtained mixture, and hardness of a sheet-like cured product of the obtained mixture,
Elongation and tensile strength were measured in the same manner as in Example 1. Table 1 shows the results.

Example 3 A mixture was obtained in the same manner as in Example 1 except that 10 parts of the cyclic organopolysiloxane represented by the formula (10) was added. Pot life at 20 ° C. of the obtained mixture, and hardness of a sheet-like cured product of the obtained mixture,
Elongation and tensile strength were measured in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 A mixture was obtained in the same manner as in Example 1 except that the cyclic organopolysiloxane represented by the formula (10) was not added. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 1 shows the results.

[0032]

[Table 1]

Example 4 In Example 4, instead of the cyclic organopolysiloxane represented by the formula (10), a compound represented by the following formula (11) was used.

Embedded image (Wherein, s is an integer of 3 to 10). A cyclic organopolysiloxane mixture represented by the following formula (the compounding ratio of each cyclic organopolysiloxane in which s is an integer of 3 to 10 is as shown in Table 2. ) Was obtained in the same manner as in Example 1 except that 3 parts of was used. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 3 shows the results.

Example 5 A mixture was obtained in the same manner as in Example 5 except that 5 parts of the cyclic organopolysiloxane mixture represented by the formula (11) was added. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 3 shows the results.

Example 6 A mixture was obtained in the same manner as in Example 6 except that 10 parts of the cyclic organopolysiloxane mixture represented by the formula (11) was added. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 3 shows the results.

[0036]

[Table 2]

[0037]

[Table 3]

Example 7 60 parts of dimethylpolysiloxane having a hydroxyl group at both molecular terminals (viscosity at 25 ° C .: 5000 cp) and calcium carbonate
Forty parts were kneaded with a three-roll mill to obtain a non-flowable paste-like mixture. To 100 parts of the paste mixture, the above formula (8)
A mixture of 2.3 parts of the compound represented by the formula and 0.2 parts of the compound represented by the formula (9), and the compound represented by the formula (12):

Embedded image Were added and mixed with stirring. Pot life at 20 ° C. of the obtained mixture, and hardness of a sheet-like cured product of the obtained mixture,
Elongation and tensile strength were measured in the same manner as in Example 1. Table 4 shows the results.

Example 8 A mixture was obtained in the same manner as in Example 7 except that 4 parts of the linear organopolysiloxane represented by the above formula (12) was used. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 4 shows the results.

Example 9 A mixture was obtained in the same manner as in Example 7 except that 8 parts of the linear organopolysiloxane represented by the above formula (12) was used. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 4 shows the results.

Comparative Example 2 A mixture was obtained in the same manner as in Example 7 except that the linear organopolysiloxane represented by the formula (12) was not added. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 4 shows the results.

[0042]

[Table 4]

Example 10 In Example 10, a cyclic organopolysiloxane represented by the formula (10) was replaced with a compound represented by the formula (13):

Embedded image (Wherein, t is an integer of 0 to 8). A linear organopolysiloxane mixture represented by the following formula (wherein t is an integer of 0 to 8; ) Was obtained in the same manner as in Example 1 except that 3 parts were used. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 6 shows the results.

Example 11 Example 11 was repeated except that 5 parts of the linear organopolysiloxane mixture represented by the above formula (13) was used.
A mixture was obtained in the same manner as in 10. The pot life of the obtained mixture at 20 ° C., and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 6 shows the results.

Example 12 A mixture was obtained in the same manner as in Example 10 except that 10 parts of the linear organopolysiloxane mixture represented by the above formula (13) was used. The pot life of the obtained mixture at 20 ° C. and the hardness, elongation and tensile strength of the sheet-like cured product of the obtained mixture were measured in the same manner as in Example 1. Table 6 shows the results. Comparative Example 3 In Comparative Example 3, the straight chain represented by the above formula (13)
At 25 ° C instead of the organopolysiloxane mixture
With a terminal viscosity of 100CS
Methyl polysiloxane (degree of polymerization: about 80) (Shin-Etsu Chemical Co., Ltd.)
(KF-96 100CS manufactured by Sangyo Co., Ltd.)
Except for the above, a mixture was obtained in the same manner as in Example 10. The resulting blend
Pot life of the compound at 20 ° C. and the resulting mixture
The hardness, elongation and tensile strength of the cured sheet
The measurement was performed in the same manner as in Example 1. Table 6 shows the results.
You.

[0046]

[Table 5]

[0047]

[Table 6]

[0048]

The two-part room temperature curable organopolysiloxane composition of the present invention has a pot life at about 0 to 50 ° C. of 1 to 10 without changing the physical properties of the cured product obtained by curing. It can be extended for about an hour. Therefore, an appropriate length of pot life can be obtained even in a high temperature in summer, and workability is good. Therefore, the composition of the present invention is useful, for example, as an architectural sealing material used for joints of buildings, particularly when used in summer.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tetsuo Tomizawa 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside the Silicon Electronics Research Laboratory, Shin-Etsu Chemical Co., Ltd. JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 83/06 C08L 83/04

Claims (2)

(57) [Claims] 1. A compound containing (A) 100 parts by weight of a diorganopolysiloxane having hydroxyl groups at both ends of a molecular chain, and (B) a compound containing on average more than 2.0 substituted aminoxy groups bonded to silicon atoms in one molecule. Wherein the substituted aminoxy group has the general formula (1): (Wherein R ¹ and R ² may be the same or different and are monovalent hydrocarbon groups), and a group represented by the general formula (2): (Wherein R ³ is a divalent organic group) 0.1 to 30 parts by weight of a nitrogen-containing organosilicon compound which is at least one selected from the group consisting of groups represented by the following formulas: 200 parts by weight, and (D) general formula (3): (Wherein n is an integer of 3 to 10) and a cyclic organopolysiloxane represented by the general formula (4): (Wherein m is an integer of 0 to 8), and the pot life including at least 1 to 50 parts by weight of at least one selected from the group consisting of linear organopolysiloxanes represented by the formula (1) is extended. Room temperature curable organopolysiloxane composition. 2. A cured product obtained by curing the organopolysiloxane composition curable at room temperature according to claim 1.