JP2001200161A - Room temperature curable organopolysiloxane composition - Google Patents

Abstract

(57) Abstract: A (A) represented by the following general formula (1) shown in the organohydrogenpolysiloxane ^{_{HO (SiR 1 2 O) n}} H (1) ( In the formula, R ¹ 1 carbon atoms 10 to 10 unsubstituted or substituted monovalent hydrocarbon groups, and R ¹ may be the same or different, and n is an integer of 10 or more.) (B) Bonding to a silicon atom Silane compound having two or more hydrolyzable groups in one molecule or partial hydrolyzate thereof 0.1 to 30 parts by weight (C) Organic zirconium compound 0.1 to less than 0.5 part by weight A room temperature-curable organopolysiloxane composition characterized by comprising: According to the room temperature curable organopolysiloxane composition of the present invention, the dry time to touch (tack free time)
At the same time, it is possible to obtain a room temperature-curable organopolysiloxane composition which does not change the curing speed and can suppress cracks. This silicone rubber is useful as a sealing material for building materials and the like which is frequently constructed on site.

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, and more particularly to a room-temperature-curable organopolysiloxane composition suitable as a sealing material capable of extending a touch-drying time. About.

[0002]

BACKGROUND OF THE INVENTION Moisture-crosslinkable room temperature vulcanizable (RTV) silicone rubbers are:
Since it is easy to handle and has excellent weather resistance and electrical properties, it is applied in various fields such as sealing materials for building materials and adhesives in the field of electric and electronic devices.

[0003] Particularly, for general industrial use and architectural use, deoxime type RTV silicone rubbers which adhere well to various adherends and have excellent weather resistance are widely used. Therefore, various properties are imparted to the deoxime type RTV silicone rubber. For example, as a composition imparted with fungicidal properties which is used around water in houses, 2-
A method of adding (4-thiazolyl) -benzimidazole (JP-A-54-127960) and a method of adding an N-substituted benzimidazolyl carbamate derivative (JP-A-56-38348) are known.

[0004] In recent years, the art of building aesthetics has improved,
Appearance has become even more important. Therefore, the technique of extending the touch dry time (tack free time) is very important from the viewpoint of emphasizing aesthetics in construction.
Usually, an attempt to extend the touch dry time (tack free time) is to slow down the curing speed, and there is an economically disadvantageous problem that the application time is long. Therefore, it was difficult to extend the tack-free time (touch-drying time) without increasing the working time, that is, without changing the curing speed.

On the other hand, in order to shorten the construction time, it is also important to follow the movement of the sealed joint until the sealing material is completely cured. As the method, there are proposals in Japanese Patent Nos. 2,837,658 and 2,635,156. In Japanese Patent No. 2837658, an organic titanate compound is added, and in Japanese Patent Application Laid-Open No. 2-55768, an organic zirconium compound is added. In both cases, a curing catalyst is added to the composition, and these components are cracked. A specific amount is added to suppress the generation. Therefore, although it is possible to suppress the generation of cracks to some extent by using this method,
At the same time, it was impossible to easily control the formation speed of the cured film in the early stage of curing, that is, the dry time to touch (tack free time).

JP-A-59-94948 proposes a polysiloxane composition having reduced properties by using an organic titanium compound or an organic zirconium compound instead of an organotin compound as a curing catalyst. However, the curability was insufficient due to the small amount of the catalyst.

Accordingly, an object of the present invention is to extend the touch dry time (tack free time) mainly,
It is another object of the present invention to provide a room-temperature-curable organopolysiloxane composition that does not change the curing speed and can suppress cracks.

[0008]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above object, and as a result, have found that a hydroxyl-terminated organopolysiloxane represented by the following general formula (1) is obtained. The specific amount of the organic zirconium compound is based on the room temperature-curable organopolysiloxane composition containing, as a main component, a silane compound having two or more hydrolyzable groups bonded to a silicon atom in one molecule or a partial hydrolyzate thereof. It has been found that the above object can be achieved by the addition of. That is, by adding the organic zirconium compound in an amount of from 0.1 part by weight to less than 0.5 part by weight based on 100 parts by weight of the hydroxyl-terminated organopolysiloxane, the touch dry time (tack free time) can be extended, and the sealing can be performed. It has been found that the speed of forming a cured film (sealing material film) in the early stage of curing of the material can be easily controlled. Furthermore, at the same time, in the curing process of the sealing material, it can be confirmed that the sealing material can sufficiently follow the movement of the sealed joint and suppress the generation of cracks in the sealing material due to the movement of the joint. Confirm that there is no inferiority when comparing the curing speed with the sealing material being cured,
The present invention has been completed.

Accordingly, the present invention, (A) 100 parts by weight of organopolysiloxane ^{_{HO (SiR 1 2 O) n}} H (1) ( wherein represented by the following general formula (1), R ¹ is 1 to the number of carbon atoms 10 unsubstituted or substituted monovalent hydrocarbon groups, and R ^{1 's} may be the same or different from each other, and n is an integer of 10 or more.) Silane compound having two or more bonded hydrolyzable groups in one molecule or partial hydrolyzate thereof 0.1 to 30 parts by weight (C) Organic zirconium compound 0.1 to less than 0.5 part by weight And a room temperature curable organopolysiloxane composition comprising:

Hereinafter, the present invention will be described in more detail. The component (A) of the room temperature-curable organopolysiloxane composition of the present invention is an organopolysiloxane represented by the following general formula (1). ^{_{HO (SiR 1 2 O) n}} H (1)

In the above formula (1), R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group. An alkyl group such as a cycloalkyl group; an alkenyl group such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; a phenyl group;
Aryl groups such as tolyl groups; aralkyl groups such as benzyl group and phenylethyl group, or groups in which the hydrogen atoms of these groups have been partially substituted with halogen atoms such as chlorine, fluorine and bromine, such as trifluoropropyl group And a methyl group and a phenyl group are preferred, and a methyl group is particularly preferred. R ¹ may be the same or different. N in the formula (1) is an integer of 10 or more, and the viscosity of this organopolysiloxane at 25 ° C. is in the range of 25 to 500,000 cSt, particularly 500 to 500 cSt.
Preferably, it is in the range of 100,000 cSt.

The component (B) is a silane compound having two or more hydrolyzable groups such as a ketoxime group, an alkoxy group and an alkenoxy group bonded to a silicon atom in one molecule or a partially hydrolyzed product thereof. is there.

In the present invention, as the silane compound, ketoxime silane and alkoxysilane are preferable, and a ketoxime group-containing silane compound represented by the following general formula (2) is particularly preferable. _{^{R 3 a Si (ON = CR}} 2 2) 4-a (2) ( wherein, R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an R ² are identical to each other R ³ is an unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and a is 0, 1 or 2.) Here, R ² is the above R ^{The same} ones as those described in ¹ can be exemplified, and as R ³ , the unsubstituted ones among those mentioned in R ¹ can be exemplified.

A specific example of the hydrolyzable silane compound (B) is methyltris (dimethylketoxime).
Silane, methyltris (methylethylketoxime) silane, ethyltris (methylethylketoxime) silane, methyltris (methylisobutylketoxime) silane, vinyltris (methylethylketoxime) silane, vinyltris (dimethylketoxime) silane, phenyltris (methylethylketoxime) silane, phenyltris (Dimethylketoxime) silane In addition to ketoxime silane represented by formula (2) such as silane, methyltrimethoxysilane, methyltriacetoxysilane, methyltriisopropenoxysilane, vinyltrimethoxysilane, vinyltri (2-methoxyethoxy) Various silanes such as silane and vinyltriacetoxysilane are exemplified, and these can be used alone or in combination of two or more.

The silane compound or its partial hydrolyzate is used in an amount of 0.1 to 30 parts by weight, preferably 1 to 15 parts by weight, based on 100 parts by weight of the organopolysiloxane (A). If the amount is too small, sufficient crosslinking cannot be obtained, and the composition having the desired rubber elasticity will not be obtained. If the amount is too large, the mechanical properties will be poor.

The organic zirconium compound of the component (C) is
It is the most important component in the present invention and is added to impart properties of the composition of the present invention. That is, its properties make it possible to easily control the speed of formation of the cured film in the initial stage of curing of the composition, and in the curing process, sufficiently follow the movement of the sealed joint, and the sealing by the movement of the joint. This makes it possible to suppress the occurrence of cracks in the material.

In the present invention, as the organic zirconium compound, a compound represented by the following general formula (3) is preferable. Zr (OR ⁴ ) ₄ (3) (wherein, R ⁴ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and R ⁴ may be the same or different. Here, as R ^{4, the same} as those described above for R ¹ can be exemplified.

As specific examples of the organic zirconium compound as the component (C), tetrapropoxy zirconate and tetrabutoxy zirconate are particularly preferable. The compounding amount of the component (C) is the same as that of the organopolysiloxane 10 of the component (A).
0.1 parts by weight or more and less than 0.5 parts by weight with respect to 0 parts by weight,
Preferably it is 0.1 to 0.45 parts by weight, particularly preferably 0.1 to 0.4 parts by weight. If the amount is less than 0.1 part by weight, the above effect is insufficient. If the amount is more than 0.5 part by weight, the durability of the rubber after curing is deteriorated. In particular, under the accelerated deterioration condition of the sunshine weather meter, the deterioration is remarkable, and the physical properties of the rubber are greatly reduced, so that the use outdoors is greatly suppressed.

In the present invention, 1 to 50 parts by weight, particularly 5 to 30 parts by weight, of a reinforcing silica filler such as fumed silica or wet silica is mixed with 100 parts by weight of the organopolysiloxane (A). Is preferred. In particular, fumed silica whose surface is hydrophobized with reactive silane, siloxane, silazane or the like is preferable, and fumed silica treated with dimethyldichlorosilane is particularly preferable. In this case, methyltrichlorosilane, trimethylmonochlorosilane, or the like may be mixed within 50% by weight. By blending it, the physical properties such as weather resistance are remarkably improved, and the tack-free time is further improved, and cracks can be suppressed.

Further, a condensation catalyst may be used to accelerate the curing of the composition. As the condensation catalyst, for example, an organotin compound and / or an organotitanium compound, which are conventionally generally used as a curing accelerator for such a composition, are preferably used.

For example, organic tin compounds such as dimethyldimethoxytin, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dibenzylmalate, dioctyltin diacetate, tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, tetraoctoxytitanium Titanium, diisopropoxytitanium ethyl acetoacetate, diisopropoxytitanium acetylacetonate and the like.
More than one species can be used in combination.

The amount of the condensation catalyst to be used is generally 10 parts by weight or less, preferably 0.0001 to 5 parts by weight, especially 0.0% by weight, based on 100 parts by weight of the organopolysiloxane (A).
It is preferably from 1 to 2 parts by weight. When the use amount of the condensation catalyst exceeds 10 parts by weight, it acts on those where the performance of the obtained cured product is deteriorated, such as shortening of initial tack-free and deterioration of storage stability. May be impaired.

In the composition of the present invention, fillers, additives and the like generally known as optional components may be used, if necessary, in addition to the above components. As the filler, for example, quartz powder, titanium oxide, calcium carbonate, zinc carbonate,
Talc and the like. Additives include polyether as a thixotropic agent, an inorganic or organic fungicide, an antibacterial agent, dimethyl silicone oil having both ends blocked with a trimethylsilyl group, and γ-aminopropyltriethoxy as an adhesion aid. Silanes, aminosilanes such as 3-2- (aminoethylamino) propyltrimethoxysilane, γ-glycidylpropyltrimethoxysilane, β-
Epoxysilanes such as (3,4-epoxycyclohexyl) ethyltrimethoxysilane are exemplified.

The organopolysiloxane composition curable at room temperature of the present invention can be prepared by mixing the above-mentioned components by a usual method, and the obtained composition is applied to various adherends to form an adhesive. Can be used as In this case, various resins can be used as the adherend, and specific examples thereof include PBT (polybutylene terephthalate), HIPS (high impact polystyrene), and acrylic resin. Since the composition of the present invention has excellent adhesiveness to PBT, HIPS, and acrylic resin, which were particularly difficult to adhere to among these, these resins can be suitably used as an adherend.

The curing conditions and the like of the composition of the present invention are the same as those of a known room-temperature curable organopolysiloxane composition of this kind.

The composition of the present invention is particularly preferably used as a sealing material. In this case, the composition of the present invention has an extended touch dry time (tack free time) without changing the curing speed. Specifically, the composition was filled in an open container having an inner diameter of 10 mm, and heated at 23 ° C. and 50 ° C.
% RH for 1 day, and then cured at a temperature of 2.4 mm or more and cured at a temperature of 23 ° C./5
After curing (hardening) at 0% RH for 7 days, JIS A
Those having a dry-to-touch time of 8 minutes or more, preferably 10 minutes or more, measured according to the method specified in 5758, are effectively used.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Example 1 The viscosity at 25 ° C. was 20,
To 90 parts by weight of polydimethylsiloxane whose ends of 000 cSt were blocked with silanol groups, 10 parts by weight of fumed silica whose surface was treated with dimethyldichlorosilane was added and mixed with a mixer, and then 6 parts by weight of methyltributanoxime silane. , And thoroughly mixed under reduced pressure. Further, 1.0 part by weight of γ-aminopropyltriethoxysilane and 0.1 part by weight of tetrabutoxyzirconate are added, and the mixture is completely mixed under reduced pressure to obtain Sample 1. Was.

Example 2 A sample 2 was obtained by using 0.4 parts by weight of the tetrabutoxyzirconate of Example 1.

Example 3 A sample 3 was obtained by mixing 0.4 parts by weight of tetrapropoxyzirconate in place of the tetrabutoxyzirconate of Example 1.

Example 4 The viscosity at 25 ° C. was 20,
To 90 parts by weight of polydimethylsiloxane whose ends of 000 cSt were blocked with silanol groups, 10 parts by weight of fumed silica whose surface was treated with dimethyldichlorosilane was added and mixed with a mixer, and then 6 parts by weight of methyltributanoxime silane. , 0.1 parts by weight of dibutyltin dioctate,
The mixture was thoroughly mixed under reduced pressure, and 1.0 part by weight of γ-aminopropyltriethoxysilane and 0.1 part by weight of tetrabutoxyzirconate were further added. The mixture was completely mixed under reduced pressure to obtain Sample 4.

Example 5 Sample 5 was obtained by using the tetrabutoxyzirconate of Example 4 in an amount of 0.4 part by weight.

Example 6 A sample 6 was obtained by mixing 0.4 parts by weight of tetrapropoxyzirconate in place of the tetrabutoxyzirconate of Example 4.

Comparative Example 1 The viscosity at 25 ° C. was 20,
To 90 parts by weight of polydimethylsiloxane whose ends of 000 cSt were blocked with silanol groups, 10 parts by weight of fumed silica whose surface was treated with dimethyldichlorosilane was added and mixed with a mixer, and then 6 parts by weight of methyltributanoxime silane. , 0.1 parts by weight of dibutyltin dioctate,
The mixture was thoroughly mixed under reduced pressure, 1.0 part by weight of γ-aminopropyltriethoxysilane was further added, and the mixture was completely mixed under reduced pressure to obtain Sample 7.

Comparative Example 2 0.1 part by weight of tetrabutoxytitanate was added to Comparative Example 1 and mixed thoroughly under reduced pressure.
Sample 8 was obtained.

Comparative Example 3 0.4 part by weight of tetrabutoxytitanate was added to Comparative Example 1 and mixed thoroughly under reduced pressure.
Sample 9 was obtained.

Comparative Example 4 To Comparative Example 1, 0.4 parts by weight of titanium diisopropoxydiacetylacetonate was added and thoroughly mixed under reduced pressure to obtain Sample 10.

Comparative Example 5 0.5 parts by weight of tetrabutoxyzirconate was added to Comparative Example 1 and thoroughly mixed under reduced pressure without adding dibutyltin dioctate to obtain Sample 11.

Tables 1 and 2 summarize the constitution of each sample in the above Examples and Comparative Examples.

Test method <General property confirmation test> Measurement method for each item: A sheet having a thickness of 2 mm was molded, and was subjected to 23 ° C.
After curing at 50% RH for 7 days, physical properties were evaluated in the following manner. Drying time to the touch: Measured according to the method specified in JIS A 5758. Hardness, elongation at break, tensile strength: Measured according to the method specified in JIS K6249. <Crack generation confirmation test> The obtained sample was placed on an aluminum plate at a width of 10 mm, a length of 100 mm, and a thickness of 5 mm.
, And cured for a certain period of time in an atmosphere of 23 ° C. and 50% RH. At each elapsed time, the aluminum plate was bent at the center at 90 °, and cracks on the surface of the sealing material were confirmed. <Curing speed test> The sample was filled into a glass Petri dish having an inner diameter of 10 mm, and the thickness of the cured material was measured from the portion that was exposed to air after 23 days at 50% RH for 1 day. <Storage stability confirmation test> Each sample was sealed at 70 ° C,
After being heat-degraded in a drier for 7 days, the measurement was carried out in the same manner as in the above-mentioned general characteristic confirmation test.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

According to the organopolysiloxane composition curable at room temperature of the present invention, the dry time to the touch (tack free time) can be extended, and at the same time, the curing speed is not changed and cracks are suppressed. A room temperature curable organopolysiloxane composition is obtained. This silicone rubber is useful as a sealing material for building materials and the like which is frequently constructed on site.

Claims (6)

[Claims] 1. A (A) 100 parts by weight of an organopolysiloxane ^{_{HO (SiR 1 2 O) n}} H (1) ( wherein represented by the following general formula (1), R ¹ is an unsubstituted 1 to 10 carbon atoms Or R ¹ may be the same or different, and n is an integer of 10 or more.) (B) Hydrolysis bonded to a silicon atom A silane compound having two or more possible groups in one molecule or a partial hydrolyzate thereof 0.1 to 30 parts by weight (C) an organic zirconium compound containing 0.1 to 0.5 parts by weight A room temperature curable organopolysiloxane composition, comprising: 2. The composition according to claim 1, wherein the component (B) is a silane compound having two or more ketoxime groups represented by the following general formula (2) per molecule or a partial hydrolyzate thereof. During _{^{R 3 a Si (ON = CR}} 2 2) 4-a (2) ( wherein, R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, R ³ is 1 to 10 carbon atoms Is an unsubstituted monovalent hydrocarbon group, and a is 0, 1 or 2.) 3. An organic zirconium compound as the component (C) is a compound represented by the following general formula (3): Zr (OR ⁴ ) ₄ (3) (wherein R ⁴ is an unsubstituted or substituted monovalent carbon having 1 to 10 carbon atoms). 3. The composition according to claim 1, which is a hydrogen group. 4. The composition according to claim 1, further comprising 1 to 50 parts by weight of fumed silica whose surface has been hydrophobized. 5. The composition according to claim 4, wherein the treating agent for the hydrophobizing treatment is dimethyldichlorosilane. 6. The dry time to the touch after hardening at 23 ° C. and 50% RH for 7 days is 8 minutes or more, and 23 ° C. and 50% RH.
The composition according to any one of claims 1 to 5, wherein a curing rate when cured with H for one day is 2.4 mm or more.