JPH0254859B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyorganosiloxane composition that is stable in the absence of moisture and cures into a rubbery state at room temperature in the presence of moisture, and more specifically to an adhesive polyorganosiloxane that does not cause the surface of silicone rubber to become resinous. Regarding the composition. Polyorganosiloxane compositions that are stable in a sealed, moisture-free state and harden at room temperature when exposed to moisture are disclosed in Japanese Patent Publication No. 39-27643 and Japanese Patent Publication No. 1977-40.
It is widely known from publications such as Publication No. 21631, and is widely used in the architecture, civil engineering, electrical, electronic, and automotive industries as well as in general households as a so-called one-pack silicone sealant, coating material, elastic adhesive, etc. . The adhesion and stability of such polyorganosiloxane compositions have been improved by adding various additives. For example, in order to improve the adhesion of such a room temperature moisture curable polyorganosiloxane composition, as disclosed in Japanese Patent Publication No. 11272/1983,
Excellent adhesive properties are obtained by adding an organosilicon compound in which an N-substituted or unsubstituted aminoalkyl group and a hydrolyzable group are bonded to a silicon atom. However, when adding such an organosilicon compound having a hydrolyzable group bonded to a silicon atom and a carbon functional group in one molecule, especially when the amount of the organosilicon compound added exceeds a certain limit,
Since the organosilicon compound is hydrolyzed after the composition is cured, the surface of the rubber-like cured composition becomes resinous, resulting in a decrease in physical properties and durability. Therefore, it has been practically difficult to add a sufficient amount of the organosilicon compound to improve adhesion and stability. As a result of intensive studies to prevent such surface resin formation, the present inventors discovered that the composition contains a compound having a polyoxyalkylene chain, particularly polyoxyalkylene or a copolymer of polyoxyalkylene and polyorganosiloxane. It was discovered that the surface resin formation could be prevented by doing so, and the present invention was completed. The following technique is known as an example of blending a compound having a polyoxyalkylene chain into a polyorganosiloxane composition that can be cured at room temperature. (1) JP-A-54-127960 When adding 2-(4-thiazolyl)-benzimidazole as a mold inhibitor to moisture-curable polyorganosiloxane, the presence of a surfactant improves the mold prevention effect. . As the surfactant, those having a polyoxyalkylene chain in the molecule may also be used. (2) Japanese Patent Publication No. 56-34226 A moisture-curable polyorganosiloxane composition using a silicon compound having an acyloxy group, an acyloxy group and an alkoxy group, or an αβ-substituted vinyloxy group as a crosslinking agent is added at the end of a polyoxyalkylene chain. Polyorganosiloxane with hydroxyl groups
When a polyoxyalkylene copolymer is blended, it does not sag during the final curing stage even when applied to a vertical surface.
So-called non-sag properties can be imparted. (3) JP-A-55-60557 This is a technique for obtaining a moisture-curable elastic body from polyorganosiloxane and polyoxyalkylene into which a silicon-containing group with a silicon functional group bonded to the terminal is introduced. Compounds with alkylene chains form an elastic network structure. (4) JP-A-56-76452, JP-A-56-76453 A moisture-curable polyorganosiloxane composition, particularly a composition using an organosilicon compound having a diorganoaminoxy group as a crosslinking agent, has an interface. Adding an activator has the effect of preventing surface stains. As the surfactant, those having a polyoxyalkylene chain in the molecule may also be used. However, none of these known documents are the object of the present invention. There is no mention of preventing the surface of the cured composition from becoming resinous, and the blending of compounds having polyoxyalkylene chains is done from a completely different perspective. Accordingly, the present invention provides a new technique that cannot be easily predicted over these existing techniques. That is, the present invention focuses on the following components (A) to (E), that is, (A) general formula HO[R ¹ ₂ SiO] _o H (wherein R ¹ is the same or different 1
valent substituted or unsubstituted hydrocarbon group, n is (A)
100 parts by weight of a polydiorganosiloxane whose terminals are blocked with hydroxyl groups (representing the number that gives a viscosity of 100 to 500,000 cP at 25°C), (B) 3 or more ketoxime groups bonded to silicon atoms in one molecule. (C) 0.01 to 3 parts by weight of a curing catalyst, (D) General formula R ^R2 _a R ³ _b Si(OR ⁴ ) _4-ab (however, R ² is an organic group containing at least one substituted or unsubstituted amino group in the molecule bonded to a silicon atom through a carbon atom, R ³ is a methyl group, and R ⁴ is an alkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms a total of 1 to 6 alkoxyalkyl groups,
a is the number 1 or 2, b is the number 0 or 1, a
+b indicates the number 1 or 2) 0.01 to 20 parts by weight of the silane, and (E) 0.1 to 0.1 to 20 parts by weight of a polyoxyalkylene chain-containing compound
50 parts by weight of an adhesive polyorganosiloxane composition. The polydiorganosiloxane (A) used in the present invention is represented by the general formula HO[R ¹ ₂ SiO] _o H (R ¹ and n are as described above) as described above, and has a viscosity at 25°C. α, ω of 100~500000cP
-dihydroxypoly(diorganosiloxane). Examples of R ¹ include methyl group, ethyl group,
Examples include monovalent hydrocarbon groups such as propyl group, butyl group, vinyl group, and phenyl group, and monovalent substituted hydrocarbon groups such as chloromethyl group, cyanoethyl group, and 3,3,3-trifluoropropyl group. . It is preferable that 85% or more of R ¹ is a methyl group in order to have an appropriate curing speed, appropriate fluidity before curing and ease of handling, and physical properties after curing, especially low modulus. Because of the ease of synthesis
It is best if all of R ¹ are methyl groups, but
When heat resistance and cold resistance are particularly required, a phenyl group is preferably used as a part of R ¹ . The range of n varies depending on the type of R ¹ and its molar ratio, but
From the viewpoint of ease of handling, fluidity of the composition, and physical properties after curing, the viscosity of (A) is selected to be 100 to 500,000 cP at 25°C, and when all R ¹ are methyl groups, n is equivalent to 20-3000. Among these, those having a viscosity of 500 to 200,000 cP are more preferable. This is because 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 curing properties tend to deteriorate. (B) used in the present invention is a crosslinking agent that crosslinks (A) to give a network structure, and for this purpose, it is necessary to use a silane having three ketoxime groups bonded to a silicon atom or a partially hydrolyzed condensate thereof. things are used. Examples of the ketoxime group bonded to a silicon atom include dialkylketoxime groups such as dimethylketoxime group, diethylketoxime group, and methylethylketoxime group, and examples of such compounds include methyltris(diethylketoxime)silane. , methyltri(methylethylketoxime)silane, vinyltri(methylethylketoxime)silane, phenyltri(methylethylketoxime)silane, and partially hydrolyzed condensates thereof. Although these dialkyl ketoxime group-containing silanes are slightly corrosive to copper-based metals, they are not corrosive to other metals, have a good balance of properties such as curing speed and adhesion, and are resistant to irritation. It has no odor and is easy to synthesize. The amount of component (B) silane or its partially hydrolyzed condensate added is 0.5~
The amount is 25 parts by weight, preferably 3 to 10 parts by weight. This is because if it is less than 0.5 parts by weight, it will be insufficient as a crosslinking agent and the curability of the composition will decrease, and if it is more than 25 parts by weight, it will be liberated and form a film on the surface, resulting in an increase in modulus. The curing catalyst (C) used in the present invention includes carboxylic acid metal salts such as iron octoate, cobalt octoate, manganese octoate, zinc octoate, tin naphthenate, tin caprylate, and tin oleate; dibutyltin diacetate;
Examples include organic tin compounds such as dibutyltin dioctoate, dibutyltin dilacrate, dibutyltin dioleate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis(triethoxysiloxy)tin, and dioctyltin dilaurate. Organosilicon compounds are preferred because they have a large catalytic ability even when present in a small amount, and diorganotin dicarboxylate salts with good curability are especially preferred. The amount of curing catalyst (C) added is 0.01 to 3 parts by weight. If the amount added is less than this, it will be insufficient as a curing catalyst, and curing will take a long time, and curing will be poor in areas far from the surface in contact with air. On the other hand, if the amount is greater than this, the storage stability of the composition will decrease, which is not appropriate. A more preferable range of addition amount is 0.1 to 2 parts by weight. Component (D) used in the present invention has the general formula R ^R2 _a R ³ _b Si(OR ⁴ ) _4-ab (R ² , R ³ .R ⁴ , a,
b is a silane represented by (as described above). As mentioned above, such silanes are used as adhesion improvers for moisture-curable polyorganosiloxane compositions using crosslinking agents such as (B).
There is a drawback that the surface of the composition after curing becomes resinous. However, according to the present invention, the adhesion improver can be effectively used without such disadvantages due to component (E) described below. Among component (D), the carbon functional group is γ-aminopropyl group, δ-
In the case of aminobutyl group, N-methyl-γ-aminopropyl group, N-(β-aminoethyl)-γ-aminopropyl group, the effect of improving adhesion is remarkable, and the composition is They play an important role in providing adhesive properties, but on the other hand, they also have a large influence on the surface resin formation after curing.
Examples of such compounds include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, δ-aminobutyltrimethoxysilane, δ-aminobutyltriethoxysilane,
N-methyl-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-eminopropyltrixysilane are shown. The amount of component (D) added is 0.01 to 20 parts by weight, preferably 0.1 to 5 parts by weight. If the amount added is less than this, it will be insufficient to improve the adhesive properties, and if it is more than this, the storage stability of the composition will be lowered or yellowing will occur after curing. The polyoxyalkylene chain-containing compound (E) used in the present invention forms the basis of the present invention,
It is effective in preventing resin from forming on the surface of a rubber-like elastic body obtained by curing a composition consisting of (A), (B), (C), and (D), and improving physical properties and durability. Examples of the polyoxyalkylene group include a polyoxyethylene group, a polyoxypropylene group, and a polyoxytrimethylene group. Specific compounds include: C ₄ H ₉ [CH ₂ CH ₂ O] _p H (p = 5-500); C ₄ H ₉ O [CH ₂ CH ₂ O] _p CH ₃ (p = 5-500) ; C ₄ H ₉ O [CH ₂ CH ₂ O] _p [CH ₂ CH ₂ O] _p H
(p+q=5-500, p/q=0.01-100); HO[ _CH2CH ( _CH3 )O] _qOH ( _q = _5-400 ); C4H9O[ _CH2CH ( _CH2 ) O] _q OH
(q=5-400), their alkyl ethers, alkyl phenyl ethers, and (CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] _x [(CH ₃ )SiR ⁵ O ] _y
Si(CH ₃ ) ₃ (where R ⁵ represents a polyoxyalkylene chain bonded to the silicon atom through one or more carbon atoms; x = 0 to 100, y = 1 to 20) Examples include polyorganosiloxane-polyoxyalkylene copolymers. All of these are commercially produced and easily available. In the present invention, the amount of the polyoxyalkylene chain-containing compound (E) added is 0.1 per 100 parts by weight of (A).
~50 parts by weight, preferably 0.3 to 10 parts by weight.
At the end of 0.1 part by weight, the effect of preventing surface resin formation is not exhibited, and when it is too much, it is not only meaningless and uneconomical, but also makes the cured product soft and oil bleed easily. In the present invention, fillers and other additives may be added as necessary. There are reinforcing fillers and non-reinforcing fillers.Reinforcing fillers include fumed silica, pyrogenic silica, precipitated silica, smokeless titanium, and their surfaces are treated with organochlorosilanes, polyorganosilates, etc. Examples include siloxanes and those made hydrophobic with hexamethyldisilazane, etc. Non-reinforcing fillers include calcium carbonate, organic acid surface-treated calcium carbonate, diatomaceous earth, ground silica, aluminosilicate, magnesia, Examples include alumina. Note that, when a particularly low modulus is required, it is preferable to use non-reinforcing fillers among these fillers. In addition, various additives such as pigments, thixotropic agents, viscosity modifiers to improve extrusion workability, ultraviolet inhibitors, fungicides, heat resistance improvers, and flame retardants can be added. is also possible. The composition of the present invention can be obtained by mixing all of the above-mentioned components and, if necessary, various additives while keeping moisture out. The obtained composition can be stored as it is in a closed container and used as a so-called one-pack room-temperature-curable polyorganosiloxane composition, which is cured only by exposure to moisture in the air at the time of use. The composition of the present invention can also be used as a so-called two-pack room-temperature-curable polyorganosiloxane composition, in which these components are stored in separate containers as appropriate, and mixed at the time of use. According to the present invention, it becomes easy to prevent the surface of a cured product of a room temperature moisture-curable polyorganosiloxane composition from becoming resinous, and it is possible to improve physical properties and durability. In addition, with this technology, even when a component (D) that has an adverse effect on the surface resinization of the composition after curing is used as an adhesion improver, the presence of (E) can eliminate such adverse effects and increase the amount of addition. can be increased. Such compositions are useful as industrial, architectural and household sealants, coatings, and elastic adhesives. Furthermore, the composition of the present invention is simple but highly effective because it contains an easily available polyoxyalkylene chain-containing compound, and is also easy to produce. The present invention will be explained in more detail with reference to Examples below. In the description of Examples, all parts mean parts by weight, and viscosity is the value at 25°C. Further, in the examples, the following compounds A-1 to A-6 were used as polyoxyalkylene chain-containing compounds. Example 1 14 parts of dry process silica with a specific surface area of 200 m ² /g were added to 100 parts of α-ω-dihydroxypolydimethylsiloxane with a viscosity of 200,000 cP, and the mixture was uniformly kneaded to obtain a base compound B-1. On the other hand, 6 parts of methyltri(methylethylketoxime)silane, γ-
3 parts of aminopropyltriethoxysilane and 1 part of dibutyltin laurate are mixed uniformly,
A crosslinking agent mixture C-1 was obtained. Take 100 parts of base compound B-1, mix it with 6 parts of C-1, and the polyoxyalkylene chain-containing compound shown in Table 1 until it becomes homogeneous while keeping moisture out, and defoam it. , samples 11-16 were prepared. In addition, Comparative Example Sample 17 using a small amount of a polyoxyalkylene chain-containing compound and Comparative Example Sample 18 using no polyoxyalkylene chain-containing compound were prepared. These were extruded into a 2 mm sheet and cured by moisture in the air to obtain a rubber-like elastic body. The physical properties and surface conditions of these rubber-like elastic bodies were as shown in Table 1. In addition, Table 1 also shows the results of observing the conditions of these samples when they were stored in a hermetically sealed state for 6 months. Note that the physical properties of the rubber-like elastic body were measured according to JISK6301.

[Table] Example 2 Ketoxime group-containing silanes, amino group-containing silanes, and dibutyltin dilaurate shown in Table 2 were uniformly mixed to form crosslinking agent mixtures C-2 to C-6.
I got it. To 100 parts of the base compound B-1 used in Example 1, 6 parts each of these crosslinking agent mixtures and polyoxyalkylene chain-containing compound A
Samples 21 to 25 were prepared by mixing 1 part of each of -1 in the same manner as in Example 1. These samples were cured in the same manner as in Example 1 to obtain rubber-like elastic bodies. The physical properties and surface condition of these rubber-like elastic bodies are
As shown in the table, no resinization of the surface was observed in any case. Also, these samples were sealed and
Although the samples were stored for several months, no changes were observed.

【table】

【table】

[Table] Example 3 To 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10,000 cP, 14 parts of dry process silica with a specific surface area of 200 m ² /g was added and uniformly kneaded to obtain base compound B-2. . Samples 31 to 33 were prepared by mixing 8 parts of the crosslinking agent mixture C-1 used in Example 1 and the polyoxyalkylene chain-containing compounds shown in Table 4 in the same manner as in Example 1. These samples were cured in the same manner as in Example 1 to obtain rubber-like elastic bodies. The physical properties and surface conditions of these rubber-like elastic bodies are shown in Table 4, and no resinization of the surface was observed in any of them. In addition, samples for measuring tensile shear adhesive strength using aluminum as an adherend were prepared from these samples according to the method of JIS K6850, and the shear adhesive strength was measured after curing. The results are also shown in Table 4.

【table】

[Table] Example 4 To 100 parts of α-ω-dihydroxypolydimethylsiloxane with a viscosity of 3000 cP, 14 parts of dry process silica with a specific surface area of 200 m ² /g and 20 parts of trimethylsilyl-terminated polydimethylsiloxane with a viscosity of 100 cP were added, and the mixture was uniformly mixed. A base compound B-3 was obtained by kneading. Sample 41 was prepared by mixing 17 parts of the crosslinking agent mixture C-1 used in Example 1 and 11 parts of the polyoxyalkylene chain-containing compound A-1 in the same manner as in Example 1. Comparative Example Sample 42 was also prepared without using A-1. These samples were cured in the same manner as in Example 1 to obtain rubber-like elastic bodies. The physical properties and surface conditions of these rubber-like elastic bodies are shown in Table 5.

【table】

【table】

Claims (1)

[Claims] 1. Components of the following (A) to (E), that is, (A) general formula HO[R ¹ ₂ SiO] _o H (provided that R ¹ is the same or different 1)
valent substituted or unsubstituted hydrocarbon group, n is (A)
100 parts by weight of a polydiorganosiloxane whose terminals are blocked with hydroxyl groups (representing the number that gives a viscosity of 100 to 500,000 cP at 25°C), (B) 3 or more ketoxime groups bonded to silicon atoms in one molecule. (C) 0.01 to 3 parts by weight of a curing catalyst, (D) General formula R ² _a R ³ _b Si(OR ⁴ ) _4-ab (however, R ² is an organic group containing at least one substituted or unsubstituted amino group in the molecule bonded to a silicon atom through a carbon atom, R ³ is a methyl group, and R ⁴ is an alkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms a total of 1 to 6 alkoxyalkyl groups,
a is the number 1 or 2, b is the number 0 or 1, a
+b indicates the number 1 or 2) 0.01 to 20 parts by weight of silane, and (E) 0.1 to 50 parts by weight of a polyoxyalkylene chain-containing compound
An adhesive polyorganosiloxane composition comprising parts by weight. 2. The composition according to claim 1, wherein R ¹ is a methyl group. 3. The composition according to claim 1 or 2, wherein R ² is a γ-aminopropyl group. 4. The composition according to any one of claims 1 to 3, wherein (C) is a diorganotin dicarboxylate. 5. The composition according to any one of claims 1 to 4, wherein (E) is polyoxyalkylene. 6. The composition according to claim 1, wherein (E) is a polyorganosiloxane-polyoxyalkylene copolymer. 7. The composition according to claim 1, wherein the amount of (E) is 0.1 to 10 parts by weight.