JPS6318977B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to room temperature curable organopolysiloxane compositions, and more particularly to room temperature curable organopolysiloxane compositions with improved curability. Regarding the so-called room-temperature-curing silicone rubber, which cures at room temperature and turns into a rubber-like elastic body,
Various types are already known, and these are broadly classified into two-component types, which mix two liquids during use, and one-liquid types, which do not require such a mixing operation. In addition to the room-temperature-curable organopolysiloxane composition, which releases carboxylic acids such as acetic acid during curing, there are
Deaminoxy type, deamine type, deoxime type, and even dealcohol type are known, but
The deacetic acid, deaminoxy, deamine, and deoxime types have the disadvantage of requiring ventilation equipment because they release toxic or corrosive gases during curing, and the dealcoholization type Although it does not cause harmful gas release, it has the disadvantage that it is difficult to store the composition stably, and furthermore, the curing time is long and the resulting cured product is likely to be mechanically brittle. . In addition, for this type of room-temperature curable composition, an alkoxytitanium compound may be used as a curing accelerator, and for the above-mentioned acetic acid-free type and oxime-free type, a metal salt of an organic acid may be used as a curing co-catalyst. These substances remain in the composition after curing, and these may color the cured product, reduce its physical properties, and even have disadvantages in terms of toxicity. There was a drawback. For this reason, room-temperature-curable organopolysiloxanes that cure through a deketone reaction caused by atmospheric moisture have been developed (Japanese Patent Publications Nos. 51-39274, 51-39673, and 54-
44699), although this product has no problems with respect to adhesion or corrosion, it has the disadvantage that the ultimate elongation rate of the obtained cured product is not fully satisfactory. The present invention relates to a room-temperature-curable organopolysiloxane composition that can solve these disadvantages. b) General formula (R ¹ and R ² are the same or different groups selected from a monovalent hydrocarbon group having 1 to 8 carbon atoms, a monovalent halogenated hydrocarbon group, a monovalent cyano hydrocarbon group, or a trimethylsiloxy group, R ³ and R ⁴
is a hydrogen atom or a carbon number of the same or different type
-8 unsubstituted or substituted monovalent hydrocarbon groups, l is 0, 1, 2 or 3)
0.01-25 parts by weight (c) General formula (Here, Y is a monovalent hydrocarbon group having 1 to 8 carbon atoms,
A group selected from a monovalent halogenated hydrocarbon group, a monovalent cyano hydrocarbon group, or a trimethylsiloxy group, R ³ is the same or different group selected from unsubstituted or substituted monovalent hydrocarbon groups having 1 to 8 carbon atoms , R ³ and R ⁴ are the same as above, m is 3 to 6,
m + n = an integer of 3 to 6) 0.01 to 25 parts by weight of one or more polyfunctional organocyclosiloxanes represented by (d) General formula (Here, R ⁶ , R ⁷ , R ⁸ and R ⁹ each represent the same or different groups selected from hydrogen atoms or monovalent hydrocarbon groups.) It is characterized by comprising 0.01 to 5 parts by weight of silane or siloxane. To explain this, the present inventors have conducted various studies on room-temperature-curable organopolysiloxane compositions, and found that the main component, diorganopolysiloxane in which both ends of the molecular chain are blocked with hydroxyl groups, has the general formula () and an organocyclosiloxane containing a vinyloxy group represented by () and at least one group represented by the general formula () in one molecule.
Compositions containing silanes or siloxanes can be stored stably for long periods of time under sealed conditions that substantially exclude water. The resulting cured product has a particularly low modulus and a high elongation rate, and also exhibits excellent adhesion to various base materials, especially metals, and is resistant to corrosion. The present invention was completed by confirming that the sealant does not exhibit any properties, and that when it is used as a sealing material, it does not contaminate the surface of the sealing part and the surrounding area of the sealing part. The above as a main ingredient constituting the composition of this invention
(a) Component is the average composition formula

[Formula] (where R is a substituted or unsubstituted monovalent hydrocarbon group, a=1.90
~2.05) is a diorganopolysiloxane whose molecular chain ends are blocked with hydroxyl groups,
This R includes alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, 2-ethylbutyl group, isobutyl group, and octyl group, cycloalkyl group such as cyclohexyl group and cyclopentyl group, vinyl group, and hexenyl group. alkenyl groups such as phenyl groups, tolyl groups, xylyl groups, biphenyl groups, phenontolyl groups, aralkyl groups such as benzyl groups, phenylethyl groups, and chloromethyl groups, trichloropropyl groups, bromophenyl groups, chlorocyclohexyl groups. , halogenated hydrocarbon groups such as trifluoropropyl group, 2-cyanoethyl group, 3-
Examples include cyanated hydrocarbon groups such as cyanopropyl group, 4-cyobutyl group, and 2-cyobutyl group, but the cured product obtained from the composition of the present invention has excellent mechanical strength and good rubber elasticity. In order to be durable, it must have a viscosity of 25 cS or more at 25°C. If necessary, this siloxane may be mixed with diorganopolysiloxane whose molecular chain ends are capped with trimethylsilyl groups, and may be used in combination with this siloxane. It is desirable that the amount is equal to or less than that of the diorganopolysiloxane. Next, the bifunctional organocyclosiloxane as component (b) constituting the composition of the present invention is represented by the above formula (), and this is

[Formula] The group is isopropenyloxy group, 1-isobutynyloxy group, 1-methyl-1-propenyloxy group, 1,4-dimethyl-1,3-
Vinyloxy groups exemplified by pentadienyloxy groups and cyclohexenyloxy groups; R ¹ and R ² are methyl groups, alkyl groups such as ethyl groups, propyl groups, butyl groups; alkenyl groups such as vinyl groups and allyl groups; A hydrogen atom bonded to a triorganosiloxy group such as a trimethylsiloxy group or a triethylsiloxy group or a carbon atom of a monovalent hydrocarbon such as a 3,3,3-trifluoropropyl group partially forms a cyano group, a halogen atom, etc. It consists of a group substituted with, and examples thereof include those represented by the following formula. However, in this formula, Me is a methyl group, Pr is a propyl group (the same applies below),

[Formula] group represents any of the above groups. When component (b) is added in an amount of 25 parts by weight or more to 100 parts by weight of the diorganopolysiloxane as component (a), the shrinkage rate when the composition is cured increases, and the resulting Since the elasticity of the cured product decreases, it is added in an amount of 0.01 to 25 parts by weight, preferably 0.1 to 10 parts by weight. Furthermore, this (b)
Ingredients: Tetramethylcyclotrasiloxane

[expression] or expression The present inventor obtained the present invention by partially chlorinating this ≡SiH bond using an organosiloxane represented by as a starting material, and then subjecting the remaining ≡SiH bond to an addition reaction with trifluoropropene, and then converting this into isopropenoxylation. This is a new substance created by et al. Next, the polyfunctional organocyclosiloxane as component (c) constituting the composition of the present invention is represented by the above formula (), and this is

[Formula] The group is isopropenyloxy group, 1-isoptynyloxy group, 1-methyl-1-propenyloxy group, 1,4-dimethyl-1,3-
Vinyloxy group exemplified by pentadienyloxy group, cyclohexenyloxy group, etc.; Y is any triorganosiloxy group such as trimethylsiloxy group, triethylsiloxy group; or any alkyl group such as methyl group, ethyl group, propyl group, butyl group. , a group in which the hydrogen atom bonded to the carbon atom of an alkenyl group such as a vinyl group or a monovalent hydrocarbon group such as a trifluoropropyl group is partially substituted with a cyano group or a halogen atom. The following formula is exemplified (

[Formula] group represents any of the above groups). The amount of component (c) added to component (a) is as follows:
If the amount is less than 0.01 part by weight per 100 parts by weight of component (a), an elastic body with the desired physical properties will not be obtained.On the other hand, if it is more than 25 parts by weight, the desired elasticity of the cured product will decrease and Since the shrinkage rate increases when the diorganopolysiloxane is added,
The amount is in the range of 0.01 to 25 parts by weight, preferably 0.05 to 10 parts by weight per 100 parts by weight. This polyfunctional organocyclosiloxane is produced by combining various ketone compounds and halogenated cyclosiloxane with organic amines such as triethylamine and dimethylaniline, or metallic sodium as acid acceptors.
It is obtained by carrying out a dehalogenation reaction using zinc chloride, copper chloride, etc. as a catalyst if necessary, and it is preferable to use a polar solvent as a reaction solvent in this reaction. In addition, the silane or siloxane as component (d) constituting the composition of the present invention has at least one group represented by the above formula () in its molecule, and R ⁶ , R ⁷ , R ⁸ , Each of R ⁹ is a hydrogen atom or a monovalent hydrocarbon group, which acts as a curing aid for the composition of the present invention together with the organocyclosiloxane as components (b) and (c) described above. be. The monovalent group shown in this general formula () may be bonded to the silicon atom through any group, but it is generally bonded to the silicon atom through an alkylene group or an oxyalkylene group. This is often combined with the following formula. If the amount of silane or siloxane added as component (d) is too small, it will take a long time to form a tack-free film when the composition of the present invention is exposed to the atmosphere, and the cured product will be Internal curability is not improved either, and if the amount is too large, there is a risk that discoloration will occur when the cured product is heated due to the action of the group represented by formula (). The amount is preferably from 0.01 to 5 parts by weight, preferably from 0.1 to 2 parts by weight, per 100 parts by weight of the diorganopolysiloxane. The silane or siloxane as component (d) can be easily obtained, for example, by reacting guanidine or a guanidyl derivative with a silane or siloxane having a halogen-substituted alkyl group in the presence of an acid acceptor. The composition of the present invention comprises (a), (b), (c) and (d) as described above.
Obtained by uniformly mixing the ingredients,
If necessary, various fillers may be added to this material, such as finely powdered silica, silica aerogel, precipitated silica, diatomaceous earth, iron oxide,
Metal oxides such as zinc oxide and titanium oxide, or their surfaces treated with silane, metal carbonates such as calcium carbonate, magnesium carbonate, and zinc carbonate, asbestos, glass wool, carbon black, fine mica powder, fused silica powder, Synthetic resin powders such as polystyrene, polyvinyl chloride, and polypropylene are exemplified, but the amount added is 400 parts by weight or less, preferably 200 parts by weight or less, per 100 parts by weight of diorganopolysiloxane as component (a). It is preferable to remove the moisture contained in these materials by drying before using them. In addition, the composition of the present invention may include pigments, dyes, thixotropy improvers, anti-aging agents, antioxidants, antistatic agents,
flame retardants such as antimony oxide and paraffin chloride;
The addition of thermal conductivity modifiers such as boron nitride is optional, but this also includes so-called carbon functional silanes with groups such as amino, epoxy, and thionyl groups, as well as carboxylic acid Conventionally known additives such as metal salts and metal alcoholates may be mixed. The composition of the present invention, which consists of each of the above-mentioned components (a), (b), (c), and (d) and a filler added as necessary, can be stored stably for a long period of time under sealed conditions. When exposed to air, this material quickly hardens due to its moisture and adheres well to various substrates, especially metal surfaces, and does not emit harmful gases or cause rust on the treated surface. This is because the cured product has the characteristics that the hardening time to the deep part is fast and the elongation rate of the cured product is high, so it is suitable for sealants, caulking agents, coating agents, adhesives, It is useful as a coating agent, and it can also be used as a water repellent or fiber treatment agent by adding hydrocarbon solvents such as xylene, toluene, or diluents such as petroleum ethers, ketones, or esters, if necessary. It can be widely used in various fields as a mold release agent, mold release treatment agent, etc. Next, examples of the present invention will be given, in which all parts are by weight, Me in the formula is a methyl group, Pr is a propyl group, and the viscosity in the examples is at 25°C. The measured values are shown respectively. Example 1 Both ends of the molecular chain are blocked with hydroxyl groups, and the viscosity is
Add 40 parts of calcium carbonate whose surface has been treated with fatty acids to 60 parts of 5700cS dimethylpolysiloxane,
A base compound was made by passing it through three rolls once. Next, add this to the following formula 1.8 parts of organocyclosiloxane represented by and the following formula 0.2 parts of organocyclosiloxane represented by and the following formula A composition was prepared by adding and mixing 0.5 part of the silane represented by: Next, this composition was made into a 2 mm thick film using an extruder.
When this was molded into a sheet and left in an atmosphere of 20℃ and 55% relative humidity for 7 days, the surface and inside of the sheet simultaneously hardened and became a rubber elastic body. When the initial physical properties and the physical properties after being left at 120°C for 7 days were examined, the results shown in Table 1 below were obtained.

[Table] Example 2 Both ends of the molecular chain are blocked with hydroxyl groups, and the viscosity is
60 parts of 5700cS dimethylpolysiloxane at 110℃
A base compound was prepared by adding 40 parts of calcium carbonate, the surface of which had been dried in a nitrogen atmosphere for 2 hours and treated with fatty acids, for 30 minutes in an anhydrous closed stirring mixer. Next, add this to the following formula 7.2 parts of organocyclosiloxane shown by and the following formula 0.8 parts of organocyclosiloxane represented by and the following formula A composition was prepared by adding and mixing 1.0 part of the silane shown in an anhydrous state, followed by defoaming treatment.The composition was stable for more than 6 months in a sealed state, and did not discolor or change even after 6 months of storage. No coloration was observed, and after 6 months, this was formed into a 2 mm thick sheet and left in an atmosphere of 20°C and 55% RH for 7 days. It cured to become a rubber elastic body, and the initial physical properties of this rubber elastic body and the physical properties after heating it at 120° C. for 7 days were examined, and the results were as shown in Table 2 below.

[Table] In addition, this composition was filled into a glass shear tray with a depth of 12 mm, and left in an atmosphere of 20°C and relative humidity of 55% RH to determine the curing speed and JIS A-
When the adhesion was examined using a method similar to 5758, the following results were obtained. Curing speed: 2 to 3 mm/day Adhesion: Strong adhesion to glass, aluminum, copper, and epoxy resin Example 3 Add 100 parts of the base compound prepared in Example 1 to the following formula. 1.8 parts of organocyclosiloxane represented by and the following formula 0.2 parts of organocyclosiloxane represented by and the following formula A composition was prepared by adding 0.5 part of the silane shown below. Next, this composition was formed into a sheet with a thickness of 2 mm, and this was left in an atmosphere of 20°C and relative humidity of 55% RH for 7 days. Curing progressed simultaneously inside the sheet and it became a rubber elastic body, so we investigated the initial physical properties of this cured product and the physical properties after heating it at 120°C for 7 days, as shown in Table 3 below. gave the result.

[Table] This composition was also applied to a 2 cm x 25 cm x 1 piece made by butting together two pieces of natural marble measuring 25 cm x 25 cm x 2 cm.
When the cured product was filled into joints of 1.2 cm and exposed to the atmosphere to cure, air that was drawn in during stirring during the production of this composition was found to be present on the surface of the cured product as it contracted during curing. The so-called ``avatar phenomenon'' that appears in the sun was not observed, and the test specimen was exposed to the following natural conditions at an inclination angle of 45°: Number of days: 120 days Cumulative rainfall: 181 mm Number of rainfall: 24 times Solar energy irradiation amount: 15535/Cal/cm ² (Integrated amount, horizontal plane) (Ultraviolet radiation (300-400nm) 1290Cal/cm ² Visible light (400-700nm) 7246Cal/cm ² Infrared radiation (700-1200nm) 6999Cal/cm ² ) When exposed to No contamination phenomenon caused by this composition was observed. In addition, this composition was filled into a cylindrical polyethylene container with a depth of 70 mm and one side sealed.
When it was left in an atmosphere of 20℃ and relative humidity of 55% RH for 24 hours, the surface and inside of it hardened almost simultaneously and became a rubber elastic body. When the hardness of the cured product was examined using an Asker Hardness Tester "Dyna C" hardness meter, the results shown in Table 4 below were obtained.

[Table] Example 4 100 parts of the base compound prepared in Example 1 was added with the following formula. 1.8 parts of organocyclosiloxane represented by and the following formula 0.2 parts of organocyclosiloxane represented by and the following formula A composition was prepared by adding 0.5 part of the silane shown below. Next, the composition obtained in this way was applied to a thickness of 2 mm.
This is formed into a sheet at 20℃ and relative humidity 55%.
When it was left in an RH atmosphere for 7 days, it became a hardened rubber elastic body, so we investigated its initial physical properties and the physical properties after heating it at 120°C for 7 days, as shown in Table 5 below. The following results were obtained.

【table】

Claims (1)

[Scope of Claims] 1 (a) 100 parts by weight of diorganopolysiloxane in which both ends of the molecular chain are blocked with hydroxyl groups (b) General formula (R ¹ and R ² are the same or different groups selected from a monovalent hydrocarbon group having 1 to 8 carbon atoms, a monovalent halogenated hydrocarbon group, a monovalent cyano hydrocarbon group, or a trimethylsiloxy group, R ³ and R ⁴ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, l is 0, 1, 2, or 3).
0.01-25 parts by weight (c) General formula [Here, Y is a monovalent hydrocarbon group having 1 to 8 carbon atoms,
A group selected from a monovalent halogenated hydrocarbon group, a monovalent cyano hydrocarbon group, or a trimethylsiloxy group, R ⁵ is an unsubstituted or substituted 1 having 1 to 8 carbon atoms
Same or different groups selected from valent hydrocarbon groups, R ³ and R ⁴ are the same groups as above, m = 3 to 6, m
+n represents an integer from 3 to 6. ] 0.01 to 25 parts by weight of one or more polyfunctional organocyclosiloxanes represented by (d) General formula (Here, R ⁶ , R ⁷ , R ⁸ and R ⁹ each represent the same or different groups selected from hydrogen atoms or monovalent hydrocarbon groups.)
1. A room-temperature-curable organopolysiloxane composition comprising 0.01 to 5 parts by weight of a silane or siloxane.