JP2837658B2 - Room temperature curable polyorganosiloxane composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room temperature-curable polyorganosiloxane composition, and more particularly, to a joint which sufficiently follows the movement of joints during curing, and The present invention relates to a room-temperature-curable polyorganosiloxane composition that can reduce the occurrence of cracks due to joint movement. [0002] Room temperature-curable polyorganosiloxane compositions which cure at room temperature with moisture in the air to give a rubbery elastic material are known as so-called condensation-type room temperature-curable liquid silicone rubbers (RTVs). It is well known as silicone rubber) and is widely used in various industrial fields. This is essentially composed of a polyorganosiloxane having hydroxyl groups at both ends as a base polymer, a silane having a hydrolyzable group as a cross-linking agent, and a curing catalyst. A so-called one-package RTV in a closed container
Silicone rubber is silicone's inherent dye resistance, cold resistance,
In addition to excellent properties such as weather resistance and electrical insulation, it has adhesiveness to various materials, and easily becomes a rubbery elastic body when exposed to air from a closed container. It is often used for repairing in a wide range of industrial fields such as the manufacturing and construction industries and at home. This one-package type RTV silicone rubber has various features depending on what hydrolyzable silane is used as the crosslinking agent. As the hydrolyzable silane used for this, acetoxysilane, alkoxysilane, aminoxysilane, amidosilane, enoxysilane, ketoximatosilane and the like have been put to practical use. Among them, those using acetoxysilane are excellent in curability, and particularly exhibit excellent adhesiveness to glass, etc.
In addition, there is a problem that metal, marble, and the like are used. The one using alkoxysilane has characteristics such as no irritating odor, no corrosion on metal, and almost no solvent crack on polycarbonate. Those using aminoxysilane or amidosilane
Although there is a characteristic that a cured product with low modulus can be obtained,
On the other hand, hardening is slow. Those using enoxysilane are quick-drying and do not corrode metals, but have problems of yellowing and cost when not cured. Among these, one package type RTV silicone rubber using ketoximatosilane as a crosslinking agent is:
It has no irritating odor, has moderate curability, has almost no corrosion to metals other than copper-based metals, and is an award-winning RTV silicone rubber that is well-balanced in terms of characteristics and cost for general industrial use and construction. Have been. For this reason, various studies have conventionally been made on one-package type RTV silicone rubber using ketoximatosilane as a crosslinking agent. For example, Japanese Patent Publication No. 46-11272 discloses a method for imparting adhesiveness. Also, JP-B-56-34226 does not sag at the uncured stage even when applied to a vertical surface.
A method for imparting a so-called non-sag property is described.
However, the one-package type RTV silicone rubber using the ketoximatosilane as a crosslinking agent has one major problem that has been solved. It is the ability to follow joint movements during curing. The silicone sealant is an elastic adhesive bonding between the two members, and after curing, can sufficiently follow the movement of the joint within its elasticity range. However, during the curing, the joint cannot follow the movement of the joint and cracks are easily generated, which is not only unfavorable in appearance but also impairs the development of the sealing function. The joint movement easily occurs due to expansion and contraction of the adherend due to a temperature change, vibration, external force, and the like, and it is difficult to completely prevent this, particularly in a building.
Among the one-package type RTV silicone rubbers, those using ketoximatosilane as a cross-linking agent have a moderate degree of curability, and may undergo a plastic state during the curing process. It was easy to generate. It is an object of the present invention to provide a cross-linking agent for a ketoximatosilane which can sufficiently follow the movement of joints during curing, and thus can reduce the occurrence of cracks during curing. It is an object of the present invention to provide a room temperature curable polyorganosiloxane composition. The present inventors have made intensive studies to achieve the above object, and as a result, have found that the addition of an organic titanate compound has an effect of improving the followability of joint movement during curing. Heading, the present invention has been made. [0005] The present invention, (A) the general formula ^{_{HO [R 1 2 SiO] n}} H ( provided that, R ¹ is identical to each other or different monovalent substituted or unsubstituted hydrocarbon radical, n is (A) Of which the viscosity at 25 ° C. becomes 100 to 500,000 cP).
Parts by weight, (B) 1 ketoximato group bonded to silicon atom
0.5 to 25 parts by weight of a silane having three or more silanes per molecule and / or a partially hydrolyzed condensate thereof, (C) a curing catalyst 0.01
-3 parts by weight, (D) 0.01-1.9 parts by weight of an organic titanate compound, and (E) 0.1-1 part by weight of γ- (2-aminoethyl) aminopropyltrimethoxysilane or γ-aminopropyltriethoxysilane. And a room temperature-curable polyorganosiloxane composition. [0006] polydiorganosiloxane (A) used in the invention is, as described above general formula ^{_{HO [R 1 2 SiO] n}} H (R 1, n are as described above) are those represented by, 25 Α, ω-dihydroxypoly (diorganosiloxane) having a viscosity at 100 ° C. of 100 to 500,000 cP. Examples of R ¹ include a monovalent hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, a vinyl group, a phenyl group, a chloromethyl group, a cyanoethyl group, and a 3,3,3-trifluoropropyl group. And monovalent substituted hydrocarbon groups. It is preferable that 85% or more of R ¹ is a methyl group because of having an appropriate curing rate, appropriate flowability before curing and easy handling, and physical properties after curing, particularly low modulus. It is best that all of R ¹ are methyl groups from the viewpoint of ease, but when heat resistance and cold resistance are particularly required,
It is preferable to use a phenyl group as a part of R ¹ . Although range of n varies depending on the molar ratio and the type of R ^1, handling ease, fluidity of the composition, and the like physical properties after curing, the viscosity of (A), a 100 ～500,000CP at 25 ° C. Selected as
When R ¹ is all methyl groups, n corresponds to 20 to 3,000. Among them, the viscosity is more preferably between 500 and 200,000 cP. If it is lower than this range, it becomes difficult to obtain good physical properties, and if it is higher than this range, extrusion workability and curability tend to deteriorate. (B) used in the present invention is a cross-linking agent which cross-links (A) to give a network structure. Therefore, silane and / or silane having three or more ketoximato groups bonded to a silicon atom in one molecule are used. Alternatively, a partially hydrolyzed condensate thereof is used. Examples of the ketoximato group bonded to the silicon atom include a dimethyl ketoximato group, a diethyl ketoximato group, and a dialkyl ketoximato group such as a methyl ethyl ketoximato group.
For example, methyltris (diethylketoximato) silane, methyltris (methylethylketoximato) silane, vinyltris (methylethylketoximato) silane, phenyltris (methylethylketoximato) silane, tetrakis (methylethylketoximato) silane and partially hydrolyzed condensates thereof Are exemplified as typical ones. Although these silane compounds containing a dialkylketoximato group show some corrosiveness to copper-based metals, they have no corrosiveness to other metals, and have a good balance in properties such as curing speed and adhesiveness. It has no pungent odor and is easy to synthesize. Among these, (B) is methyltris (methylethylketoximato) silane and / or its partially hydrolyzed condensate, or vinyltris (methylethylketoximato) silane and / or The partially hydrolyzed condensate is preferably used. The amount of the component (B) silane and / or its partial hydrolyzed condensate is 10%.
0.5 to 25 parts by weight, preferably 3 to 0 parts by weight.
~ 10 parts by weight. If the amount is less than 0.5 part by weight, the curing agent of the composition is insufficient as a crosslinking agent, and the curability of the composition is lowered.
If the amount is more than the weight part, it is liberated to form a film on the surface, and the cured product has too high modulus. The curing catalyst (C) used in the present invention includes iron octoate, cobalt octoate, manganese octoate, zinc octoate, tin naphthenate,
Carboxylic acid metal salts such as tin caprylate and tin oleate; dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin dioleate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis (triethoxysiloxy) tin, dioctyl An organic tin compound such as tin dilaurate is exemplified, but since it has a large catalytic ability in the presence of a trace amount, it is preferably an organic tin carboxylate, and among them, a diorganotin dicarboxylate having good curability. Is preferred. The amount of curing catalyst (C) added is 0.01 per 100 parts by weight of component (A).
３3 parts by weight. If the addition amount is smaller than this, the curing catalyst is insufficient and it takes a long time to cure, and the curing in the interior far from the contact surface with air becomes poor. On the other hand, if the amount is more than this, the storage stability of the composition is lowered, so that it is not suitable. 0.1%
~ 2 parts by weight. The organic titanate compound (D) used in the present invention forms the basis of the present invention, and comprises (A)
The composition comprising (B) and (C) is effective for improving the followability to joint movement during curing and reducing the occurrence of cracks during curing. Examples of such organic titanate compounds include tetraalkoxytitanium such as tetrapropoxytitanium and tetrabutoxytitanium, partially hydrolyzed condensate of tetraalkoxytitanium, diisopropoxybis (acetylacetonato) titanium, trimethylenedioxybis (acetylacetate). Examples thereof include titanium chelates such as nato) titanium, diisopropoxybis (ethylacetoacetato) titanium, and trimethylenedioxybis (ethylacetoacetato) titanium. Such an organic titanate compound is preferably a liquid at ordinary temperature from the viewpoint of uniform dispersibility. The addition amount of the organic titanate compound is (A)
It is 0.01 to 1.9 parts by weight based on 100 parts by weight of the component. If the amount is less than this, the expression of the followability to the movement of the joint during curing is not sufficient, and if it is more than this, the viscosity of the composition increases, the extrudability decreases, and the workability deteriorates,
The degree of yellowing becomes strong and the storage stability deteriorates, which is not appropriate. A more preferable range of the addition amount is 0.05 to 1.5 parts by weight. The component (E) used in the present invention is γ- (2
-Aminoethyl) aminopropyltrimethoxysilane or γ-aminopropyltriethoxysilane, and the addition of such aminoalkoxysilane further improves the adhesion. For the purpose of the addition, the amount of the aminoalkoxysilane added is 0.1 to 1 part by weight. In the present invention, a filler and other additives are blended if necessary. Fillers include reinforcing and non-reinforcing ones. Reinforcing fillers include fumed silica, calcined silica, precipitated silica, fumed titanium and the surfaces of which are treated with organochlorosilanes, polyorganosiloxanes. And non-reinforcing fillers such as calcium carbonate, organic acid surface-treated calcium carbonate, diatomaceous earth, ground silica, aluminosilicate, magnesia, alumina and so on. When it is required to have a particularly low modulus, it is preferable to use a non-reinforcing filler among them. The additives include a pigment, a thixotropy-imparting agent, an adhesion improver, a viscosity modifier for improving extrusion workability, an ultraviolet ray inhibitor, a fungicide, a heat resistance improver, and a flame retardant. It is also possible to add various additives such as. The composition of the present invention comprises the above (A), (B),
It can be obtained by mixing the components (C), (D) and (E) and the filler as required, in a state where moisture is shut off. However, if all of the components (A), (B), (C), (D), and (E) are mixed at once, the rapid thickening and structural Formation occurs, making uniform mixing somewhat difficult. Therefore, a preferred preparation method is
First, the components (A), (B), (C) and (E), and the filler, if necessary, are uniformly mixed while keeping moisture out, and (A) and
This is a method in which the reaction with (B) is allowed to proceed sufficiently, and thereafter, the component (D) is added to the mixture, followed by uniform mixing again with the moisture being shut off. In addition, various additives as needed are the first.
Can be added at the time of mixing, or can be added at the time of the second mixing. The obtained composition can be used as a so-called one-package room temperature-curable polyorganosiloxane composition which is stored as it is in a closed container and cured only by exposing it to moisture in the air at the time of use. Further, in the composition of the present invention, these components may be appropriately divided and stored in separate containers, and these may be mixed at the time of use, and may be used as a so-called two-package room temperature-curable polyorganosiloxane composition. According to the present invention, it is possible to provide a room-temperature moisture-curable polyorganosiloxane composition which releases a ketoxime compound at the time of curing and which can sufficiently follow the movement of joints during curing. In addition, such a composition can reduce the occurrence of cracks during curing. Such a composition which is less likely to crack during the course of curing is preferable as a silicone sealing material for both construction and general industrial use. In particular, it is particularly preferable as a silicone sealing material used in a construction site where the joint is largely affected by the influence of the outside temperature fluctuation upon curing and it is substantially impossible to prevent the joint from moving. The present invention will be described below by way of examples. Here, all parts are parts by weight, and all physical properties such as viscosity are 25
It is a value at ° C. Me, Vi, and Ph represent a methyl group, a vinyl group, and a phenyl group, respectively. Example 1 100 parts of α, ω-dihydroxydimethylpolysiloxane having a viscosity of 200,000 cP was mixed with dry silica 14 having a specific surface area of 200 m ² / g.
Were added and kneaded uniformly to obtain a base compound B-1. Separately, 140 parts of methyltris (methylethylketoximato) silane, 10 parts of γ- (2-aminoethyl) aminopropyltrimethoxysilane, and 1 part of dibutyltin dilaurate were uniformly mixed to obtain a crosslinking agent mixture C-1. Take 100 parts of base compound B-1 and add 8
Of C-1 was added and kneaded uniformly with the exclusion of moisture. The composition was allowed to stand at room temperature for 4 hours under the exclusion of moisture, and then the organic titanate compound shown in Table 1 was added. Prepared. In addition, Comparative Example Sample 12 using no organic titanate compound
Was prepared. These are extruded into a 2 mm sheet,
It was left at 60% RH for 168 hours and cured by the moisture in the air to obtain a rubber-like elastic body. In addition, a bending test was performed to measure the followability to joint movement. This extrudes the sample into a bead with a diameter of about 7 mm on paper etc.
The sample is left in an atmosphere of 60% RH and bent outward by 90 ° every predetermined time to check whether cracks occur in the bead of the sample. Table 1 shows the physical properties of these rubbers and the results of the bending test. [Table 1] Example 2 In order to examine the followability of the joint movement to the actual joint movement, the joint movement was measured using the samples 2, 5 and 12 (Comparative Example) used in Example 1 by utilizing the contraction caused by the temperature change of the joint. The follow-up property to was investigated. The joints are 15mm in length and width and 300mm in length. This joint is about 4% 20 minutes after placing the sample,
It shrank about 8% after 60 minutes and reached a temperature equilibrium at about 9% shrink. The results are as shown in Table 2. In the case of the product of the present invention, a firm film was formed on the surface after 60 minutes. [Table 2] EXAMPLE 3 Methyltris (methylethylketoximato) silane 110
Part, vinyltris (methylethylketoximato) silane
30 parts, 8 parts of γ-aminopropyltriethoxysilane, and 1 part of dibutyltin dilaurate are uniformly mixed,
A crosslinker mixture C-2 was obtained. 100 parts of the base compound B-1 used in Example 1 was added, and 8 parts of C-2 was added thereto and kneaded uniformly while keeping out moisture. The composition is dried under moisture barrier for 2 hours.
After allowing the mixture to stand at room temperature for a period of time, 0.7 part of trimethylenedioxybis (ethylacetoacetato) titanium was added thereto, mixed until the mixture became uniform while keeping moisture out, and defoamed to prepare Sample 31. Rubber properties were measured in the same manner as in Example 1, and a bending test was performed. The result is hardness 31, tensile strength 29kgf / cm
^{2. The} elongation was 340%, and no crack was observed in the bending test. Example 4 C-2 was added to 100 parts of the base compound B-1 used in Example 1.
Was added and mixed homogeneously while keeping moisture out. After leaving this composition at room temperature for 2 hours under the exclusion of moisture, the following compound: The samples were mixed at the ratios shown in Table 3 in a state where moisture was shut off until they became uniform, followed by defoaming to prepare sample samples 41 to 45 and sample samples 46 to 47 of comparative examples. As to these samples, as in Example 1, the mechanical properties and the contact dry time at 25 ° C. and 60% RH and the stability test were carried out after leaving each sample in a sealed condition at 70 ° C. for 3 days. Were measured for similar characteristics. A storage condition of 70 ° C. for 3 days corresponds to a storage period of at least 6 months at 25 ° C. Table 3 shows the results. [Table 3]

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuyoshi Shinozawa 133 Nishishinmachi, Ota City, Gunma Prefecture Toshiba Siri Cone Corporation (72) Inventor Isao 133 Nishishinmachi, Ota City, Gunma Prefecture Toshiba Siri Cone Corporation (72) 72) Inventor Satoru Kohama 133 Nishishinmachi, Ota City, Gunma Prefecture Toshiba Silicon Co., Ltd. (72) Inventor Seizo Muto 133 Nishishinmachi, Ota City, Gunma Prefecture Toshiba Siricon Co., Ltd. Cl. ⁶ , DB name) C08L 83/06 C08K 5/05 C08K 5/54

Claims (1)

(57) [Claims] (A) the general formula ^{_{HO [R 1 2 SiO] n}} H ( provided that, R ¹ is identical to each other or different monovalent substituted or unsubstituted hydrocarbon radical, n is 100 to a viscosity at 25 ° C. for (A) A polydiorganosiloxane terminated with a hydroxyl group represented by the following formula:
Parts by weight, (B) 1 ketoximato group bonded to silicon atom
0.5 to 25 parts by weight of a silane having three or more silanes per molecule and / or a partially hydrolyzed condensate thereof, (C) a curing catalyst 0.01
-3 parts by weight, (D) 0.01-1.9 parts by weight of an organic titanate compound, and (E) 0.1-1 part by weight of γ- (2-aminoethyl) aminopropyltrimethoxysilane or γ-aminopropyltriethoxysilane. A room temperature curable polyorganosiloxane composition comprising: 2. (B) is methyltris (methylethylketoximato)
2. The composition according to claim 1, which is silane and / or a partially hydrolyzed condensate thereof, or vinyltris (methylethylketoximato) silane and / or a partially hydrolyzed condensate thereof. 3. The composition according to claim 1, wherein (C) is an organotin carboxylate and / or a derivative thereof.