Method for producing thixotropic curable silicone compositions

Abstract

A method for producing a thixotropic curable silicone composition is disclosed, the thixotropic curable silicone composition comprising (A) a silicone base material containing an organopolysiloxane having at least two alkoxysilyl groups per molecule and a filler other than fumed silica, (B) hydrophobic fumed silica, (C) a carbasilatrane derivative, (D) an alkoxysilane or its partial hydrolysis and condensation product, and (E) a condensation reaction catalyst, the method comprising the following steps: (I) mixing components (A) and (B), (II) mixing component (C) with the mixture obtained in step (I), and then (III) mixing components (D) and (E) with the mixture obtained in step (II) under moisture-free conditions. The curable silicone composition obtained by this method has thixotropic properties and can be cured at room temperature upon contact with moisture in the air.

Description

[Technical field]

[0001] The present invention relates to a method for making a thixotropic curable silicone composition that can be cured at room temperature upon contact with atmospheric moisture. [Background technology]

[0002] Room temperature curable silicone compositions that can be cured by contacting with moisture in air are used as sealants, adhesives, or coatings for electrical / electronic devices because they do not require heating to cure. In certain applications, the thixotropic properties of the curable silicone composition are required to keep its shape after it is dispensed. It is well known that the thixotropic properties of the curable silicone composition are generally obtained by adding fine fillers such as hydrophobic fumed silica and some kinds of organic liquid compounds with polar groups such as silanol groups, epoxy groups, amine groups, or polyether groups.

[0003] For example, Patent Document 1 discloses a room-temperature curable silicone composition that contains a diorganopolysiloxane in which both ends of the molecular chain are terminally capped with silanol groups, an organosilicon compound having a hydrolyzable group, a filler, and a silicone-modified polyoxyalkylene compound.

[0004] Patent Document 2 discloses a method for preparing a thixotropic silicone dispersion consisting essentially of mixing a hydroxyl-endcapped dimethylpolysiloxane, a hydroxyl-endcapped diorganosiloxane oligomer having phenyl or 3,3,3-trifluoropropyl groups, then mixing untreated fumed silica, then mixing alumina trihydrate powder, then mixing (D) a non-reactive solvent, and then mixing a moisture-activated crosslinking system for the dimethylpolysiloxane under conditions in the absence of moisture.

[0005] Patent Document 3 discloses a room-temperature-curable silicone composition that contains an organopolysiloxane having at least two specific alkoxysilyl-containing groups on silicon atoms in a molecular chain in one molecule, an organopolysiloxane that has neither hydroxyl groups nor alkoxy groups on silicon atoms in the molecular chain, an alkoxysilane or a partial hydrolysis and condensation product thereof, a condensation reaction catalyst, and optionally an adhesion promoter and / or a reinforcing filler.

[0006] Prior art documents Patent Literature Patent Document 1: U.S. Patent No. 4,618,646(A) Patent Document 2: U.S. Patent No. 5,036,131(A) Patent Document 3: U.S. Patent No. 8,957,153 (B2) Summary of the Invention [Problem to be solved by the invention]

[0007] However, the aforementioned compositions have poor thixotropic properties, which can cause problems when the composition hardens and spreads to undesired areas of the electrical / electronic device.

[0008] An object of the present invention is to provide a method for producing a thixotropic curable silicone composition that has excellent thixotropic properties and can be cured at room temperature upon contact with moisture in the air. [Means for solving the problem]

[0009] Solution to the problem The method of the present invention for producing a thixotropic curable silicone composition, the thixotropic curable silicone composition comprising: (A) a silicone-based material comprising 100 parts by weight of an organopolysiloxane having at least two alkoxysilyl-containing groups represented by the following formula in each molecule: -R 3 -(SiR1 2O) n -SiR 1 2-R 3 -SiR 1 a (OR 2 ) (3-a) In the formula, R 1 are the same or different alkyl groups having 1 to 6 carbon atoms, R 2 are the same or different alkyl groups having 1 to 3 carbon atoms, R 3 are the same or different alkylene groups having 2 to 6 carbon atoms, "a" is 0 or 1, and "n" is an integer from 1 to 10, and the silicone base material includes 100 to 500 parts by weight of a filler other than fumed silica; (B) 100~400m 2 / g BET specific surface area, (C) A carbasilatrane derivative represented by the following general formula: [ka] In the formula, R 4 is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, and R 5 are the same or different and are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 6 are the same or different and are selected from the group represented by the following general formula: -R 9 -SiR 7 b (OR 8 ) (3-b) -R 10 -OR 11 In the formula, R 7 is an alkyl group having 1 to 6 carbon atoms, and R 8 is an alkyl group having 1 to 3 carbon atoms, and R 9 is an alkylene group having 2 to 6 carbon atoms or an alkyleneoxyalkylene group having 4 to 12 carbon atoms, and R 10is an alkylene group having 2 to 6 carbon atoms, and R 11 is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an acyl group having 2 to 6 carbon atoms, and "b" is 0, 1, or 2; (D) an alkoxysilane or a partial hydrolysis and condensation product thereof, wherein the alkoxysilane is represented by the general formula: R 12 c Si(OR 13 ) (4-c) In the formula, R 12 is an alkyl group containing 1 to 6 carbon atoms, and R 13 is an alkyl group containing 1 to 3 carbon atoms and "c" is 1 or 2, or an alkoxysilane or a partially hydrolyzed and condensed product thereof; (E) a condensation reaction catalyst, the content of component (B) is 0.1 to 50 parts by mass per 100 parts by mass of the organopolysiloxane in component (A); The content of component (C) is 0.1 to 20 parts by mass, the content of component (D) is 0.5 to 30 parts by mass, and the content of component (E) is 0.1 to 10 parts by mass; The method comprises the following steps: (I) mixing components (A) and (B), followed by (II) mixing component (C) with the mixture obtained in step (I) above; and (III) The method includes a step of mixing components (D) and (E) with the mixture obtained in step (II) above under moisture-free conditions.

[0010] The filler in component (A) is typically selected from iron oxide, titanium oxide, aluminum oxide, zinc oxide, aluminum hydroxide, magnesium hydroxide, fused silica, crystalline silica, quartz, diatomaceous earth, calcium carbonate, magnesium carbonate, zinc carbonate, or mixtures thereof.

[0011] Component (A) is typically prepared by mixing an organopolysiloxane and a thermally conductive filler in the presence of a surface treatment agent under heating at 60 to 250°C.

[0012] The surface treatment agent is typically hexamethyldisilazane, tetramethyldivinyldisilazane, or vinyltrimethoxysilane.

[0013] Component (C) is typically a carbasilatrane derivative represented by the following formula: [ka]

[0014] Step I is typically carried out at 10 to 50°C.

[0015] Step II is typically carried out at 10 to 50°C.

[0016] Step III is typically carried out at 10 to 50°C.

[0017] Effect of the Invention According to the method of the present invention, the curable silicone composition obtained by this method has excellent thixotropic properties and can be cured at room temperature upon contact with moisture in the air.

[0018] definition The terms "comprising" or "comprise" are used herein in their broadest sense to mean and encompass the terms "including," "include," "consist(ing) essentially of," and "consist(ing) of." The use of "for example," "eg," "such as," and "including" to list examples does not limit the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to," and includes other similar or equivalent examples. As used herein, the term "about" serves to reasonably encompass or account for slight variations in numerical values ​​as determined by instrumental analysis or as a result of handling samples. Such slight variations may be on the order of ±0-25%, ±0-10%, ±0-5%, or ±0-2.5% of the numerical value. Furthermore, the term "about" applies to both numerical values ​​when relating to a range of values. Furthermore, the term "about" may apply to numerical values ​​even if not expressly stated.

[0019] It should be understood that the appended claims are not limited to the expressions and specific compounds, compositions, or methods described in the detailed description, which may vary among the specific embodiments within the scope of the appended claims. With respect to any Markush group relied upon herein describing detailed features or aspects of various embodiments, it should be understood that different, special, and / or unexpected results may be obtained from each element of the respective Markush group independent of all other Markush elements. Each element of the Markush group may be relied upon individually and / or in combination to provide sufficient support for a particular embodiment within the scope of the appended claims.

[0020] Any ranges and subranges relied upon in describing various embodiments of the present invention should also be understood to be within the scope of the appended claims, both individually and inclusively, and all ranges including integer and / or fractional values ​​are understood to be described and contemplated, even if such values ​​are not expressly written herein. Those skilled in the art will readily recognize that the recited ranges and subranges fully describe and enable various embodiments of the present invention, and that such ranges and subranges may be further delineated into relevant halves, thirds, fourths, fifths, etc. As merely an example, the range "0.1-0.9" may be further delineated into a lower third, i.e., 0.1-0.3, a middle third, i.e., 0.4-0.6, and an upper third, i.e., 0.7-0.9, which are individually and inclusively within the scope of the appended claims and may be relied upon individually and / or inclusively to fully support specific embodiments within the scope of the appended claims. Furthermore, with respect to words defining or modifying a range, such as "at least," "greater than," "less than," "less than," etc., such words should be understood to include subranges and / or upper or lower limits. As another example, the range "at least 10" essentially includes the subranges of at least 10 to 35, at least 10 to 25, 25 to 35, etc., each of which may be relied upon individually and / or inclusively to fully support certain embodiments within the scope of the appended claims. Finally, individual numbers within the disclosed ranges may be relied upon to fully support certain embodiments within the scope of the appended claims. For example, the range "1 to 9" includes various individual integers, such as 3, as well as individual numbers (or fractions) including decimal points, such as 4.1, which may be relied upon to fully support certain embodiments within the scope of the appended claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The process of the present invention for producing a curable silicone composition will now be described in detail.

[0022] The curable silicone composition obtainable by the method of the present invention comprises: (A) a silicone base material containing a filler other than organopolysiloxane and fumed silica; (B) hydrophobic fumed silica, (C) Carbasilatrane derivatives, (D) alkoxysilanes or their partial hydrolysis and condensation products, and (E) Contains a condensation reaction catalyst.

[0023] Component (A) is an organopolysiloxane having in each molecule at least two alkoxysilyl-containing groups represented by the following formula: -R 3 -(SiR 1 2O) n -SiR 1 2-R 3 -SiR 1 a (OR 2 ) (3-a)

[0024] In the formula, R 1 are the same or different alkyl groups having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a heptyl group, with the methyl group being preferred from the viewpoints of economic efficiency and heat resistance.

[0025] In the formula, R 2 are the same or different alkyl groups having 1 to 3 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group, with the methyl group being preferred from the viewpoint of the curability of the composition.

[0026] In the formula, R 3 are the same or different alkylene groups having 2 to 6 carbon atoms. Examples of the alkylene group include an ethylene group, a methylethylene group, a propylene group, a butylene group, a pentylene group, and a heptylene group, with the ethylene group and the propylene group being preferred from the viewpoints of economic efficiency and heat resistance.

[0027] In the formula, “a” is 0 or 1, preferably 0.

[0028] In the formula, “n” is an integer of 1 to 10, and is preferably 1.

[0029] Examples of alkoxysilyl-containing groups include groups represented by the formula: -C2H4-Si(CH3)2O-Si(CH3)2-C2H4-Si(OCH3)3 -C3H6-Si(CH3)2O-Si(CH3)2-C2H4-Si(OCH3)3 -C2H4-Si(CH3)2O-Si(CH3)2-C2H4-SiCH3(OCH3)2 -C2H4-Si(CH3)2O-Si(CH3)2-C3H6-Si(OCH3)3 -C3H6-Si(CH3)2O-Si(CH3)2-C3H6-Si(OCH3)3 -C2H4-Si(CH3)2O-Si(CH3)2-C6H 12 -Si(OCH3)3 -C2H4-[Si(CH3)2O]2-Si(CH3)2-C2H4-Si(OCH3)3

[0030] The silicon-bonded organic groups other than the alkoxysilyl-containing groups in the organopolysiloxane are not limited, but examples include monovalent hydrocarbon groups having 1 to 12 carbon atoms and containing no aliphatic unsaturated bonds. The monovalent hydrocarbon groups are exemplified by methyl, ethyl, propyl, or similar alkyl groups; phenyl, tolyl, xylyl, or similar aryl groups; benzyl, phenethyl, or similar aralkyl groups; and 3-chloropropyl, 3,3,3-trifluoropropyl, or similar halogenated alkyl groups, with methyl being preferred from the standpoint of economic efficiency and heat resistance.

[0031] The molecular structure of the organopolysiloxane is not limited, but examples include linear, partially branched linear, and branched. The viscosity of the organopolysiloxane at 25° C. is not limited, but is preferably in the range of about 100 to about 1,000,000 mPa s, or in the range of about 100 to about 100,000 mPa s, or in the range of about 100 to about 10,000 mPa s.

[0032] Methods for synthesizing such organopolysiloxanes are known in the art, and U.S. Patent Nos. 4,687,829(A), 4,711,928(A), 4,772,675(A), 4,871,827(A), 4,888,404(A) and 4,898,910(A) are incorporated herein by reference to show the preparation of organopolysiloxanes.

[0033] The filler in component (A) is not limited, but is typically selected from iron oxide, titanium oxide, aluminum oxide, zinc oxide, aluminum hydroxide, magnesium hydroxide, fused silica, crystalline silica, quartz, diatomaceous earth, calcium carbonate, magnesium carbonate, zinc carbonate, or mixtures thereof.

[0034] Component (A) is typically prepared by mixing the organopolysiloxane and the filler in the presence of the surface treatment agent under heating at 60 to 250°C, preferably 100 to 200°C.

[0035] Examples of surface treatment agents include, but are not limited to, organodisilazanes, alkenyl-group-containing alkoxysilanes, alkyl-group-containing alkoxysilanes, alkoxy-functional oligosiloxanes, cyclic polyorganosiloxanes, hydroxyl-functional oligosiloxanes, organochlorosilanes, or any combination of at least two thereof. The organodisilazanes may be hexamethyldisilazane, 1,3-divinyl-trimethyldisilazane, or any mixture of two or more thereof. The alkenyl-group-containing alkoxysilanes may be vinyltrimethoxysilane, methylvinyldimethoxysilane, allyltrimethoxysilane, allylmethyldimethoxysilane, or any mixture of two or more thereof. The alkyl-group-containing alkoxysilanes may be hexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetradecyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, or any combination of at least two thereof. Alkoxy-functional oligosiloxanes are (CH3O)3Si[(OSi(CH3)2]C8H 17 , (CH3O)3Si[(OSi(CH3)2] 10 C8H 17 , (CH3O)3Si[(OSi(CH3)2]C 12 H 25 , (CH3O)3Si[(OSi(CH3)2] 10 C 12 H 25 or any combination of at least two thereof. The hydroxyl-functional oligosiloxane may be dimethylsiloxane or methylphenylsiloxane. The organochlorosilane may be methyltrichlorosilane, diethyldichlorosilane, or trimethylchlorosilane.

[0036] The amount of surface treatment agent is any amount sufficient to prepare the filler. The specific amount can vary depending on factors such as the particular treatment agent selected and the surface area and amount of untreated filler to be treated. The amount effective for treatment can range from 0.01% to 20%, alternatively from 0.1% to 15%, alternatively from 0.5% to 5%, by weight, based on the weight of component (A).

[0037] Typically, the process steps include contacting and mixing the components in a device suitable for mixing. The device is not particularly limited, but may be, for example, a stirred batch kettle, a ribbon blender, a solution blender, a co-kneader, a twin rotor mixer, a Banbury type mixer, or an extruder for compositions with relatively high fluidity (low dynamic viscosity). The process may use a continuous kneading device such as an extruder, for example, an extruder, a twin screw extruder (e.g., Baker Perkins Sigma Blade Mixer or a high shear Turello Mixer), etc., to prepare a composition containing a relatively large amount of particulate matter. The composition may be prepared in a batch, semi-batch, semi-continuous, or continuous process. General methods are known, for example, U.S. Patent Application Publication Nos. 2009 / 0291238 and 2008 / 0300358.

[0038] Component (B) is 100 to 400 m 2 / g, preferably 150 to 400m 2 / g, or 200-400m 2 / g, because when the BET specific surface area of ​​the fumed silica is within the above range, the thixotropic properties of the curable silicone composition are improved.

[0039] The content of component (B) is about 0.1 to about 50 parts by mass, preferably about 0.5 to about 30 parts by mass, or about 1 to about 20 parts by mass, or about 1 to about 15 parts by mass, per 100 parts by mass of the organopolysiloxane in component (A). This is because when the content of component (B) is at or above the lower limit of the above range, the thixotropic properties of the curable silicone composition are improved, and when the content of component (B) is at or below the upper limit of the above range, the handleability of the curable silicone composition is improved.

[0040] Component (C) is a carbasilatrane derivative represented by the following general formula: [ka]

[0041] In the formula, R 4 is an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group, with the methyl group being preferred from the viewpoints of economic efficiency and heat resistance. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group.

[0042] In the formula, R 5 and are the same or different and each is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, with a methyl group being preferred from the viewpoints of economic efficiency and heat resistance.

[0043] In the formula, R 6 are the same or different and are selected from the group represented by the following general formula: -R 9 -SiR 7 b (OR 8 ) (3-b) -R 10 -OR 11 .

[0044] In the formula, R 7 is an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, with a methyl group being preferred.

[0045] In the formula, R 8 is an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group.

[0046] In the formula, R 9 is an alkylene group having 2 to 6 carbon atoms, or an alkyleneoxyalkylene group having 4 to 12 carbon atoms. Examples of the alkylene group include an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, and an octylene group, with the ethylene group and the propylene group being preferred from the viewpoint of economic efficiency. Examples of the alkyleneoxyalkylene group include an ethyleneoxyethylene group, a propyleneoxyethylene group, a butyleneoxypropylene group, and a propyleneoxypropylene group, with the ethyleneoxypropylene group and the propyleneoxypropylene group being preferred from the viewpoint of economic efficiency.

[0047] In the formula, R 10 is an alkylene group having 2 to 6 carbon atoms. Examples of the alkylene group include an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, and an octylene group, with the ethylene group and the propylene group being preferred from the viewpoint of economic efficiency.

[0048] In the formula, R 11 is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an acyl group having 2 to 6 carbon atoms. Examples of the alkyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, and a hexenyl group, with an allyl group being preferred. Examples of the acyl group include an acetyl group, a propionyl group, an acryl group, a methacryl group, a butyryl group, and an isobutyryl group, with an acetyl group being preferred.

[0049] In the formula, "b" is 0, 1, or 2, preferably 0 or 1.

[0050] Examples of the carbasilatrane derivative of component (C) include compounds represented by the following formula: [ka] [ka] [ka] [ka]

[0051] Methods for synthesizing such carbasilatrane derivatives are known in the art. Japanese Patent No. 3831481 (B2) and U.S. Patent No. 8,101,677 (B2) are incorporated herein by reference to show the preparation of carbasilatrane derivatives.

[0052] The content of component (C) is about 0.1 to about 20 parts by mass, preferably about 1 to about 20 parts by mass, or about 1 to about 10 parts by mass, per 100 parts by mass of the organopolysiloxane in component (A). This is because when the content of component (C) is at or above the lower limit of the above range, the thixotropic properties of the curable silicone composition are improved, and when the content of component (C) is at or below the upper limit of the above range, the storage stability of the curable silicone composition is improved.

[0053] Component (D) functions as a crosslinker for the composition and is an alkoxysilane, or a partial hydrolysis and condensation product thereof, the alkoxysilane being represented by the general formula: R 12 c Si(OR 13 ) (4-c)

[0054] In the formula, R12 is an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, with a methyl group being preferred.

[0055] In the formula, R 13 is an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group.

[0056] In this formula, "c" is 0, 1, or 2.

[0057] Examples of component (D) include trifunctional alkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, and phenyltrimethoxysilane, tetrafunctional alkoxysilanes such as tetramethoxysilane and tetraethoxysilane, and the partial hydrolysis and condensation products of the foregoing. A single alkoxysilane or its partial hydrolysis and condensation products may be used, or a mixture of two or more may be used.

[0058] The content of component (D) is about 0.5 to about 30 parts by mass, preferably about 0.5 to about 20 parts by mass, or about 1 to about 15 parts by mass, or about 5 to about 15 parts by mass, relative to 100 parts by mass of the organopolysiloxane in component (A). This is because when the content of component (D) is equal to or greater than the lower limit of the above range, the resulting composition exhibits sufficient curability and the storage life of the resulting composition under moisture-free conditions is extended, whereas when the content of component (D) is equal to or less than the upper limit of the above range, the resulting composition is rapidly cured by moisture in the air.

[0059] Component (E) is a condensation reaction catalyst that promotes crosslinking in the composition. Examples of component (E) include tin compounds such as dimethyltin dineodecanoate and stannous octanoate, and titanium compounds such as tetra(isopropoxy)titanium, tetra(n-butoxy)titanium, tetra(t-butoxy)titanium, di(isopropoxy)bis(ethylacetoacetate)titanium, di(isopropoxy)bis(methylacetoacetate)titanium, and di(isopropoxy)bis(acetylacetonate)titanium.

[0060] The content of component (E) is about 0.1 to about 10 parts by mass, or about 0.5 to about 10 parts by mass, or about 0.5 to about 5 parts by mass, per 100 parts by mass of the organopolysiloxane in component (A). This is because when the content of component (E) is equal to or greater than the lower limit of the above range, the resulting composition exhibits sufficient curability due to the effect of moisture in the air, and when the content of component (E) is equal to or less than the upper limit of the above range, the storage life of the resulting composition under moisture-free conditions is extended.

[0061] As long as the objectives of the present invention are not impaired, the curable silicone composition can contain other optional components, such as non-reinforcing fillers such as calcium carbonate powder, diatomaceous earth powder, and zinc carbonate powder, flame retardants, heat stabilizers, plasticizers, and pigments such as titanium oxide and carbon black.

[0062] The method of the present invention comprises the steps of: (I) mixing components (A) and (B); (II) mixing component (C) with the mixture obtained in step (I) above, followed by (III) The method includes a step of mixing components (D) and (E) with the mixture obtained in step (II) above under moisture-free conditions.

[0063] Step I is typically carried out at about 10 to about 50°C, or about 20 to about 35°C.

[0064] Step II is then preferably carried out immediately after step I, typically at about 10 to about 50°C, or about 20 to about 35°C.

[0065] Step III is then typically carried out at a temperature of 10 to 50°C, alternatively from about 20 to about 35°C.

[0066] Typically, the process steps include contacting and mixing the components in a device suitable for mixing. The device is not particularly limited, and may be, for example, a stirred batch kettle, a ribbon blender, a solution blender, a co-kneader, a twin rotor mixer, a Banbury type mixer, or an extruder for compositions with relatively high fluidity (low dynamic viscosity). The process may use a continuous kneading device such as an extruder, for example, an extruder, a twin screw extruder (e.g., Baker Perkins Sigma Blade Mixer or a high shear Turello mixer), etc., to prepare a composition containing a relatively large amount of particulate matter. The composition may be prepared in a batch, semi-batch, semi-continuous, or continuous process.

[0067] After preparation, the composition can be used immediately or can be stored for any practical period of time before use, such as 1 hour or more, or 1 day or more, or 1 week or more, or 30 days or more, or 300 days or more, or 2 years or more. The composition can be stored in a container that protects the composition from exposure to a cure trigger (e.g., a triggering agent, such as water or a lower alcohol) or triggering conditions (e.g., heat with or without a water-releasing agent). Storage is at a suitable temperature (e.g., 40°C or less, e.g., 25°C) and under an inert gas atmosphere (e.g., N2 or Ar gas), or both).

[0068] Then, when necessary, the composition can be cured (through a condensation reaction) by exposure to a cure trigger to initiate the curing. For example, the composition can be prepared by contacting it with an effective amount of a triggering agent (e.g., an appropriate amount of water, methanol, or ethanol), an effective triggering condition (e.g., heat), or both to initiate the condensation reaction catalyzed by the condensation catalyst of component (E). Exposure to environmental humidity can provide a triggering amount of water. Curing of the composition to a tack-free surface occurs in less than 2 hours, alternatively less than 1 hour, alternatively less than 20 minutes, alternatively less than 10 minutes, alternatively less than 5 minutes at 25°C. If desired, curing can be carried out at higher or lower temperatures for shorter or longer times. Upon curing, the resulting cured product can form a gum, gel, rubber, or resin.

[0069] The composition and the cured product are useful as adhesives, coatings, fillers, or sealants. The composition and the cured product can be easily incorporated on or into the substrate of the product. The substrate can be wood, vinyl products, fiberglass, aluminum, or glass. The product can be a building component (e.g., a window or door assembly), an automobile part, or an electronic component. An article can be manufactured by filling a cavity in the substrate with the composition, or by applying the composition to at least an outer or inner surface portion of the substrate by any suitable means, such as brushing, calendaring, dipping, spreading, (co)extrusion, rolling, spraying, or wiping, to obtain an article in which or on which the composition is applied. If desired, the applied composition can then be cured in or on the substrate to produce a product having a cured product. EXAMPLES

[0070] The method for producing a curable silicone composition of the present invention will be described in detail below using examples and comparative examples. However, the present invention is not limited to the description of the examples listed below. Viscosity was measured at 25°C.

[0071] The slump of the compositions was evaluated according to ASTM D2202 as follows: Place a clean flow jig against a flat, level surface with the plunger depressed to the limit of its travel (3 / 8 inch). Fill the cavity with sample. Level the surface with two passes of the blade starting at the center and moving to one side of the jig. The loading operation should be completed within 0.5 minutes and with minimal work of the sample. Immediately set the jig in a vertical position, advance the plunger to its forward limit of travel and start the timer. Allow the jig to rest for 3 hours. The sample will now flow down the face of the jig. Use the scale to record the furthest forward point. Record the results to the nearest tenth of an inch.

[0072] The following components were used to prepare curable silicone compositions of the examples and comparative examples. Component (a-1): A dimethylpolysiloxane having a viscosity of about 500 mPa×s and having trimethoxysilylethyl-containing groups represented by the following formula on silicon atoms at both ends of the molecular chain: -C2H4-Si(CH3)2OSi(CH3)2-C2H4-Si(OCH3)3. Component (a-2): A dimethylpolysiloxane having a viscosity of about 12,000 mPa×s and having trimethoxysilylethyl-containing groups represented by the following formula on silicon atoms at both ends of the molecular chain: -C2H4-Si(CH3)2OSi(CH3)2-C2H4-Si(OCH3)3. Component (a-3): Aluminum hydroxide powder having an average particle size of approximately 2 μm. Component (a-4): Aluminum hydroxide powder having an average particle size of approximately 15 μm. Component (a-5): Silica quartz powder with an average particle size of approximately 4.3 μm. Component (a-6): Fumed titanium dioxide powder having an average particle size of approximately 0.24 μm. Component (a-7): vinyltrimethoxysilane. Component (b-1): Approx. 200m 2 / g, and is a hydrophobic fumed silica powder that has been surface-treated with hexamethyldisilazane. Component (b-2): Approx. 200m 2 Hydrophobic fumed silica powder with a BET specific surface area of ​​1.0 x 100 / g and surface-treated with dimethyldichlorosilane. Component (b-3): Approx. 200m 2 Hydrophilic fumed silica powder with a BET specific surface area of ​​1.0 - 1.0 g / g. Component (c-1): A carbasilatrane derivative represented by the following formula: [ka] Component (c-2): 3-glycidoxypropyltrimethoxysilane. Component (d-1): Methyltrimethoxysilane. Component (d-2): Dimethyldimethoxysilane. Component (e-1): Diisopropoxybis(ethylacetoacetate) titanium.

[0073] Reference Example 1 (Preparation of Silicone Base Material (1)) Silicone base material (1) was prepared by high shear mixing in a Turello type high shear mixer at 25°C until a homogeneous blend was obtained by 63.7 parts by weight of component (a-1), 36.3 parts by weight of component (a-2), 138.0 parts by weight of component (a-3), 72.4 parts by weight of component (a-4), 19.2 parts by weight of component (a-5), 5.4 parts by weight of component (a-6), and 4.3 parts by weight of component (a-7), followed by heating the blend at a temperature of 120°C to 200°C under a vacuum of -0.01 to -0.1 MPa for 30 minutes to 3 hours to strip volatile materials, and cooling the remaining material to 25°C.

[0074] Example 1 The silicone base material (1) obtained in Reference Example 1 was mixed with component (b-1) in an amount of 9.1 parts by mass per 100 parts by mass of components (a-1) and (a-2) in the silicone base material (1) at 25°C until uniformly blended, to obtain mixture (1). Mixture (1) had slight fluidity and a slump of 16 mm.

[0075] Next, mixture (1) was mixed with component (c-1) in an amount of 1.8 parts by mass per 100 parts by mass of components (a-1) and (a-2) in mixture (1) at 25° C. until uniformly blended to obtain mixture (2). Mixture (2) was non-flowable and had a slump of 0 mm.

[0076] Next, mixture (2) was mixed with components (d-1), (d-2) and (e-1) in amounts of 5.8 parts by mass, 4.0 parts by mass and 4.0 parts by mass, respectively, per 100 parts by mass of components (a-1) and (a-2) in mixture (2), until uniformly blended at 25°C under an anhydrous atmosphere to obtain a curable silicone composition. The curable silicone composition was non-flowable and had a slump of 3 mm.

[0077] Example 2 The mixture (1) obtained in Example 1 was mixed with component (c-1) in an amount of 18 parts by mass per 100 parts by mass of components (a-1) and (a-2) in the mixture (1) at 25° C. until uniformly blended to obtain a mixture (3). The mixture (3) was non-fluid and had a slump of 0 mm.

[0078] Next, mixture (3) was mixed with components (d-1), (d-2) and (e-1) in amounts of 5.8 parts by mass, 4.0 parts by mass and 4.0 parts by mass, respectively, per 100 parts by mass of components (a-1) and (a-2) in mixture (3), until uniformly blended at 25°C under an anhydrous atmosphere to obtain a curable silicone composition. The curable silicone composition was non-flowable and had a slump of 4 mm.

[0079] Example 3 The silicone base material (1) obtained in Reference Example 1 was mixed with component (b-2) in an amount of 9.1 parts by mass per 100 parts by mass of components (a-1) and (a-2) in the silicone base material (1) at 25°C until uniformly blended to obtain mixture (4). Mixture (4) was non-flowable and had a slump of 0.5 mm.

[0080] Next, mixture (4) was mixed with component (c-1) in an amount of 1.8 parts by mass per 100 parts by mass of components (a-1) and (a-2) in mixture (1) at 25°C until uniformly blended to obtain mixture (5). Mixture (5) was non-flowable and had a slump of 0 mm.

[0081] Next, mixture (5) was mixed with components (d-1), (d-2) and (e-1) in amounts of 5.8 parts by mass, 4.0 parts by mass and 4.0 parts by mass, respectively, per 100 parts by mass of components (a-1) and (a-2) in mixture (5), until uniformly blended at 25°C under an anhydrous atmosphere to obtain a curable silicone composition. The curable silicone composition had slight fluidity and a slump of 16 mm.

[0082] Comparative Example 1 The mixture (1) obtained in Example 1 was mixed with components (d-1), (d-2) and (e-1) in amounts of 5.8 parts by mass, 4.0 parts by mass and 4.0 parts by mass, respectively, per 100 parts by mass of components (a-1) and (a-2) in the mixture (1), until uniformly blended, at 25°C in an anhydrous atmosphere, to obtain a curable silicone composition. The curable silicone composition had flowability and a slump of 46 mm.

[0083] Comparative Example 2 The silicone base material (1) obtained in Reference Example 1 was mixed with component (b-3) in an amount of 9.1 parts by mass per 100 parts by mass of components (a-1) and (a-2) in the silicone base material (1) at 25°C until uniformly blended to obtain mixture (6). Mixture (6) had slight fluidity and a slump of 9 mm.

[0084] Next, mixture (6) was mixed with component (c-1) in an amount of 1.8 parts by mass per 100 parts by mass of components (a-1) and (a-2) in mixture (6) at 25°C until uniformly blended to obtain mixture (7). Mixture (7) had fluidity and a slump of more than 100 mm.

[0085] Next, mixture (7) was mixed with components (d-1), (d-2) and (e-1) in amounts of 5.8 parts by mass, 4.0 parts by mass and 4.0 parts by mass, respectively, per 100 parts by mass of components (a-1) and (a-2) in mixture (7), until uniformly blended at 25°C under an anhydrous atmosphere to obtain a curable silicone composition. The curable silicone composition had flowability and a slump of more than 100 mm.

[0086] Comparative Example 3 The mixture (1) obtained in Example 1 was mixed with component (c-2) in an amount of 1.8 parts by mass per 100 parts by mass of components (a-1) and (a-2) in the mixture (1) at 25° C. until uniformly blended to obtain a mixture (8). The mixture (8) had slight fluidity and a slump of 38 mm.

[0087] Next, mixture (8) was mixed with components (d-1), (d-2) and (e-1) in amounts of 5.8 parts by mass, 4.0 parts by mass and 4.0 parts by mass, respectively, per 100 parts by mass of components (a-1) and (a-2) in mixture (8), until uniformly blended at 25°C under an anhydrous atmosphere to obtain a curable silicone composition. The curable silicone composition had flowability and a slump of 57 mm. [Industrial Applicability]

[0088] According to the method of the present invention, the thixotropic curable silicone composition obtained by this method has excellent thixotropic properties, and can be cured at room temperature by contacting with moisture in air.Therefore, the curable silicone composition is useful for the sealant, adhesive, or coating of electric / electronic devices.

Claims

1. A method for producing a curable silicone composition, comprising: (A) a silicone-based material comprising 100 parts by weight of an organopolysiloxane having at least two alkoxysilyl-containing groups represented by the following formula in each molecule: -R ３ -(SiR １ ２ O) ｎ -SiR １ ２ -R ３ -SiR １ ａ (OR ２ ) （３－ａ） In the formula, R １ are the same or different alkyl groups having 1 to 6 carbon atoms, R ２ are the same or different alkyl groups having 1 to 3 carbon atoms, R ３ is the same or different alkylene group having 2 to 6 carbon atoms, "a" is 0 or 1, "n" is an integer from 1 to 10, and the silicone base comprises 100 to 500 parts by weight of a filler other than fumed silica; (B) 150-400m ２ / g BET specific surface area; (C) A carbasilatrane derivative represented by the following general formula: 【Chemistry 1】 In the formula, R ４ is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, and R ５ are the same or different and are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R ６ are the same or different and are selected from the group represented by the following general formula: -R ９ -SiR ７ ｂ (OR ８ ) （３－ｂ） In the formula, R ７ is an alkyl group having 1 to 6 carbon atoms, and R ８ is an alkyl group having 1 to 3 carbon atoms, and R ９ is an alkylene group having 2 to 6 carbon atoms or an alkyleneoxyalkylene group having 4 to 12 carbon atoms; (D) an alkoxysilane or a partial hydrolysis and condensation product thereof, wherein the alkoxysilane is represented by the following general formula: R １２ ｃ Si(OR １３ ) （４－ｃ） In the formula, R １２ is an alkyl group having 1 to 6 carbon atoms, and R １３ is an alkyl group having 1 to 3 carbon atoms and "c" is 0, 1 or 2, or an alkoxysilane or a partially hydrolyzed and condensed product thereof; (E) a condensation reaction catalyst, the filler in component (A) is selected from iron oxide, titanium oxide, aluminum oxide, zinc oxide, aluminum hydroxide, magnesium hydroxide, fused silica, crystalline silica, quartz, diatomaceous earth, calcium carbonate, magnesium carbonate, zinc carbonate, or mixtures thereof; the content of component (B) is 0.1 to 50 parts by mass, the content of component (C) is 0.1 to 20 parts by mass, the content of component (D) is 0.5 to 30 parts by mass, and the content of component (E) is 0.1 to 10 parts by mass, relative to 100 parts by mass of the organopolysiloxane in component (A); The method comprises the steps of: (I) mixing components (A) and (B), followed by (II) mixing component (C) with the mixture obtained in step (I); and (III) mixing components (D) and (E) with the mixture obtained in step (II) under moisture-free conditions, The method wherein component (A) is prepared by mixing the organopolysiloxane and the filler in the presence of a surface treatment agent under heating at 60 to 250°C.

2. The method of claim 1 , wherein the surface treatment agent is selected from hexamethyldisilazane, tetramethyldivinyldisilazane, or vinyltrimethoxysilane.

3. The method of claim 1 , wherein component (C) is a carbasilatrane derivative represented by the following formula: 【Chemistry 2】

4. The method according to claim 1, wherein step I is carried out at 10 to 50° C.

5. The method according to claim 1, wherein step II is carried out at 10 to 50° C.

6. The method of claim 1, wherein step III is carried out at 10 to 50° C.

Images