JP4920170B2 - Room temperature curable organopolysiloxane composition - Google Patents

Description

  The present invention relates to a room temperature curable organopolysiloxane composition, and more particularly to a room temperature curable organopolysiloxane composition containing an inorganic filler, and more particularly to a one-component room temperature curable organopolysiloxane composition. .

  Among the polyorganosiloxane compositions that cure at room temperature to form rubbery elastic bodies, the so-called room temperature curable organopolysiloxane compositions of the type that undergo a curing reaction upon contact with moisture in the air are There is no need to weigh or mix the main body (base polymer), cross-linking agent, catalyst, etc. It is widely used as an elastic adhesive and coating material in industry, and as a building sealing material.

  Such a composition is generally filled with a silanol group-terminated polydiorganosiloxane whose molecular terminal is blocked with a hydroxyl group, a crosslinking agent having more than two hydrolyzable groups in the molecule, silica, calcium carbonate or the like. It consists of a combination of agents.

  Upon curing, the room temperature curable organopolysiloxane composition releases carboxylic acid such as acetic acid, organic amine, amide, organic hydroxylamine, oxime compound, alcohol, acetone and the like depending on the type of the crosslinking agent. In particular, when curing a room temperature curable organopolysiloxane composition for the purpose of an adhesive, a coating material, etc. to form a rubbery elastic body, it is of a deoxime type, a deacetone type, a decollet type Is often used.

  On the other hand, one-pack type (one-component type) room-temperature curable compositions comprising polyorganosiloxanes having alkoxy groups bonded to terminal silicon atoms, alkoxysilanes, and curing catalysts have recently been used. A polyorganosiloxane in which an alkoxy group is bonded to a terminal silicon atom is characterized by good storage stability and fast curability compared to a polyorganosiloxane having a terminal hydroxyl group.

  In addition, room temperature curable organopolysiloxane compositions represented by sealing agents and adhesives are widely used in the fields of architecture, automobiles, flooring, and the like for waterproofing and sealing purposes. There are a component type and a two-component type. In the two-component type, two components (two liquids) such as a base or main agent and a curing agent are mixed before use. In addition, the one-component type has the advantages that there is no need to weigh or mix the crosslinking agent, catalyst, etc. as described above, and that no mistakes in formulation occur.

In addition, each room temperature curable organopolysiloxane composition has a problem that if the extrudability is poor, a large force is required for extrusion and it takes time. Therefore, in these applications, the extrudability can be a very important physical property that greatly affects the construction time. In addition, since it is often applied to vertical parts, it is necessary not to sag, and physical properties such as thixotropy and slump resistance are also important. Conventionally, silicon dioxide powder such as calcium carbonate and quartz powder, titanium oxide Inorganic fillers such as these are commonly used in room temperature curable organopolysiloxane compositions.

  Room temperature curable organopolysiloxane compositions using inorganic fillers such as calcium carbonate had problems such as thickening and curing in containers during storage due to the amount of water contained in the filler. It can be improved by the preparation process of the product and the amount of the crosslinking agent. The deacetoxy type and the deoxime type have been favorably used because of their fast curing properties. However, deacetoxy has a limited use because the strong odor of carboxylic acid typified by acetic acid formed as a by-product during curing tends to be disliked in field construction and corrodes the adherend. Compared with deacetoxy, the deoxime type is less odor and corrosive and is widely used. However, due to recent concerns regarding chemical substances, dealcohol-free forms that are a by-product of alcohols that are generally considered to have less influence on the human body have been favored in the market. In recent years, members to be bonded are gradually shifting to difficult-to-adhere engineer plastics and their coated steel sheets, and it is difficult to bond with conventional deoxime types, making it difficult to cope with them. Due to its adhesiveness even in the dealcohol-free type, an alkoxy metal compound containing a metal atom of group IVB of the periodic table is used as a curing catalyst from a composition using an organotin compound, which is a curing catalyst generally used conventionally. The composition was found to have superior adhesion to engineer plastics and the like, which are difficult-to-adhere members. However, compared to organotin compounds that are generally widely used in the deacetoxy type and deoxime type, when an alkoxy metal compound containing a metal atom of Group IVB of the periodic table is used as a curing catalyst, the blending amount is reduced due to its catalytic activity. You need to do quite a lot. Among these compounds, alkoxytitanium chelates whose ligands are chelate compounds are widely used because of their relatively high catalytic activity and excellent curability, and various proposals have been made (Patent Documents 1 to 3). 7).

However, this alkoxy titanium chelate compound has low compatibility with the siloxane composition and tends to be easily separated. Therefore, when an alkoxy metal compound containing a group IVB metal atom, particularly an alkoxy titanium chelate, is blended as a curing catalyst with a room temperature curable organopolysiloxane composition, the catalyst component is on the surface of the cured product during curing. This is considered to cause a phenomenon such as causing resinification by promoting curing of the catalyst itself and curing of the crosslinking component at the surface and the adhesive interface, and causing a difference in hardness from the inside of the cured product. Further, when an inorganic filler is blended with the filler, the hardness of the cured product surface increases as the blending amount increases, and such resinization becomes noticeable. Therefore, the desired mechanical properties and adhesive strength of the cured product are not sufficiently exhibited. Further, the adhesiveness also has a problem that peeling is likely to occur in a range close to an interface, particularly a portion in contact with air.
Japanese Patent Publication No.59-15918 Japanese Patent Publication No. 56-14701 Japanese Examined Patent Publication No. 63-42942 JP 56-159251 A JP-A-62-2252456 JP-A 61-247756 JP-A 63-289069

  The present invention provides a room temperature curable organopolysiloxane composition that solves the above-mentioned drawbacks of the prior art and suppresses resinification of the cured product on the surface or adhesive interface of the cured product due to the presence of an alkoxy metal compound, particularly a titanium-based catalyst. The purpose is to provide.

  As a result of diligent research to solve the above-mentioned problems, the present inventors suppressed curing of the cured product on the surface of the cured product or the adhesive interface by blending a curing catalyst having a specific structure, and excellent mechanical properties and It has been found that a room temperature curable organopolysiloxane composition having adhesiveness can be provided, and the present invention has been completed.

That is, the present invention provides a silicon-functional polydiorgano having a mean number of hydrolyzable groups exceeding two as silicon functional groups in the molecule (A) (A1) having a viscosity at 23 ° C. of 20 to 1,000,000 cP. A room temperature curable organopolysiloxane composition comprising siloxane and / or (A2) a silicon functional polydiorganosiloxane having two or more silicon functional groups in the molecule and a cross-linking agent,
With respect to 100 parts by weight of the (A) polydiorganosiloxane,
(B) Inorganic filler 5 to 200 parts by weight (C) A room temperature-curable organopolysiloxane comprising 0.01 to 30 parts by weight of a curing catalyst represented by the following general formula (1) It is a composition.

(Wherein R ¹ and R ² represent a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other, X is a chelate group, a is a number from ¹ to ^3. n Is a number that makes the viscosity of the component (C) at 23 ° C. 10 to 100,000 cP.)

  Hereinafter, the present invention will be described in detail. In the present invention, the (A) silicon-functional polydiorganosiloxane used as the base polymer comprises the (A1) component and / or the (A2) component having the silicon functional group as described above, and the (A1) component is It itself cures by causing a crosslinking reaction by the catalytic action of the component (C). Further, the combination of the component (A2) and the crosslinking agent is cured by causing a crosslinking reaction between the component (A2) and the crosslinking agent by the catalytic action of the component (C). In either case, the reaction is a hydrolysis reaction and a subsequent condensation reaction, and the reaction proceeds in the presence of moisture in the air.

  The component (A) used in the present invention is typically represented by the following general formula (2):

(Wherein R ³ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other, R ⁴ represents —ZSiR ⁵ _3-b X _b , where Z represents oxygen and / Or represents a divalent hydrocarbon group, R ⁵ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other, X represents a hydrolyzable group, b represents 1 to 3 And m is a number that makes the viscosity of the component (A) at 23 ° C. 20 to 1,000,000 cP). The end group R ⁴ is a silicon functional siloxy unit having at least one silicon functional group X. That is, the component (A) has at least one silicon functional group X at each of both ends of the molecule.

R ³ is a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other. R1 includes methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, alkyl group such as dodecyl group; alkenyl group such as vinyl group and allyl group; phenyl group, Aryl groups such as tolyl group and xylyl group; aralkyl groups such as 2-phenylethyl group and 2-phenylpropyl group are exemplified, and some of hydrogen atoms of these hydrocarbon groups are substituted with other atoms or groups A halogenated alkyl group such as a chloromethyl group, a 3-chloropropyl group or a 3,3,3-trifluoropropyl group; a substituted hydrocarbon group such as a cyanoalkyl group such as a 3-cyanopropyl group Is exemplified. Among these, the synthesis is easy, the component (A) has a low viscosity for the molecular weight, gives good extrudability to the composition before curing, and good physical properties to the composition after curing. Therefore, 85% or more of all organic groups are preferably methyl groups, and substantially all organic groups are more preferably methyl groups.

On the other hand, particularly when imparting heat resistance, radiation resistance, cold resistance or transparency, a necessary amount of phenyl group as a part of R ³ , and when imparting oil resistance and solvent resistance, R ³ When a 3,3,3-trifluoropropyl group or 3-cyanopropyl group is given as a part, or a surface having paintability is imparted, a long-chain alkyl group or an aralkyl group is a methyl group as a part of R ^3. Can be arbitrarily selected depending on the purpose.

In the terminal groups R ^4, R ⁵ bonded to the silicon atom may be the same or different from each other, also a monovalent hydrocarbon group for R ⁵ and different it may also be substituted or unsubstituted at the same, R ³ The same thing is illustrated. A methyl group or a vinyl group is preferable because synthesis is easy and X has excellent reactivity. Z may be the same or different from each other, and examples thereof include an oxygen atom, an alkylene group such as a methylene group, an ethylene group, and a trimethylene group; and a divalent hydrocarbon group such as a phenylene group. In view of easy synthesis, an oxygen atom and an ethylene group are preferable, and an oxygen atom is particularly preferable.

X is a silicon functional group present in at least one terminal group R ⁴ , that is, an alkoxy group that is a hydrolyzable group. Examples of such X include alkoxy groups such as methoxy group, ethoxy group, propoxy group, and butoxy group; substituted alkoxy groups such as 2-methoxyethoxy group and 2-ethoxyethoxy group; enoxy groups such as isopropenoxy group, etc. These hydrolyzable groups are exemplified, and may be the same or different. An alkoxy group is preferred because of its ease of synthesis, physical properties of the composition before curing, stability during storage, curability, economy, and use in a wide range of applications. Moreover, as X with the remarkable effect of this invention, an alkoxy group is mentioned.

The number b of the silicon functional group X in the terminal group R ⁴ is 1 to 3. Among them, (A2) used for the room temperature curable organopolysiloxane composition containing a crosslinking agent is easy to synthesize and used in combination with various crosslinking agents, so that X is a hydroxyl group and b is 1. Is preferred. Such a silicon-functional polydiorganosiloxane is obtained by ring-opening polymerization or ring-opening copolymerization of a cyclic diorganosiloxane low monomer such as octamethylcyclosiloxane in the presence of water with an acidic catalyst or an alkaline catalyst. Thus, a hydroxyl group bonded to a silicon atom can be introduced into the terminal of the obtained linear polydiorganosiloxane.

A compound in which X is a hydrolyzable group can be synthesized, for example, by condensing a silane having two or more arbitrary hydrolyzable groups to a polyorganosiloxane having a hydroxyl group at the terminal. In this case, since one hydrolyzable group of the silane is consumed by this condensation reaction, the number b of X in the terminal group R ⁴ of the polyorganosilosan obtained by the reaction is the hydrolyzable used. One less than the number of X that the group-containing silane had.

  In addition, in order to give moderate extrudability to the composition before curing and to give excellent mechanical properties to the rubber-like elastic body after curing, m of the component (A) is 23 ° C. of (A). The viscosity is selected to be 20 to 1,000,000 cP. If the viscosity is less than 20 cP, the rubber-like elastic body after curing is not sufficiently stretched. On the other hand, if it exceeds 1,000,000 cP, it is difficult to obtain a uniform composition and the extrusion workability is also lowered. Particularly preferred viscosities are in the range of 500 to 200,000 cP because they match the properties required of the composition before and after curing.

  In the room temperature curable polydiorganosiloxane composition not using a crosslinking agent, among the above component (A), the component (A1), that is, X is a hydrolyzable group, and b is an average number exceeding 1 (ie, When a polymer having a number of X exceeding 2 on average is used as a base polymer, the X in the component (A) serves as a crosslinking means, and a crosslinking reaction proceeds even without a crosslinking agent. As a result, a rubber-like elastic body is produced. In this case, preferred X is an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group or a butoxy group; a substituted alkoxy group such as a 2-methoxyethoxy group or a 2-ethoxyethoxy group; an enoxy group such as an isopropenoxy group. Such an alkoxy group. An alkoxy group such as a methoxy group can be mentioned as a remarkable manifestation of the effects of the present invention. Further, it is more preferable to use such a base polymer in order to stabilize the composition before curing and to give excellent curability.

  In a room temperature curable polydiorganosiloxane composition using a crosslinking agent, a crosslinked structure is formed by using the component (A2) in combination with a crosslinking agent as the component (A). As the component (A2), one in which X is a hydroxyl group or b is 1 (that is, in the molecule having two hydroxyl groups and / or two hydrolyzable groups similar to the above) is used. it can.

  As a crosslinking agent, a silicon compound having a silicon functional group and / or partial hydrolysis thereof for reacting with the silicon functional group X in the component (A) in the presence of water and a curing catalyst to cure the composition A condensate is used.

This crosslinking agent has the following general formula (3):
R ⁶ _4-c SiY _c
(Wherein R ⁶ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same as or different from each other, Y represents a hydrolyzable group, and c represents an average of more than 2 and 4 or less. It is a number.)

R ⁶ can be exemplified by the same group as the organic group R ¹ directly bonded to the silicon atom of the component (A), and is easily available and has an excellent crosslinking reaction rate. Or a vinyl group is preferable. Examples of the hydrolyzable reactive group Y are the same as those exemplified as X existing in the terminal group of the component (A).

  Examples of such crosslinkers include tetramethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetrapropoxy. Alkoxy group-containing compounds such as silane, tetraisopropoxysilane and partial hydrolysis condensates thereof; tetrakis (2-ethoxyethoxy) silane, methyltris (2-methoxyethoxy) silane, vinyl (2-ethoxyethoxy) silane, phenyl Substituted alkoxy group-containing compounds such as tris (2-methoxyethoxy) silane and partial hydrolysis condensates thereof; methyltriisopropenoxysilane, vinyltriisopropenoxysilane, phenyltrii Propenoxyethyl silane, dimethyl isopropenoxysilane silane, such as an enoxy group-containing compounds such as methyl vinyl di- isopropenoxysilane silane and their partially hydrolyzed condensates are exemplified. Of these, silane in which c is 2 is used in combination with silane in which c is 3 or 4.

  Among these, considering that the synthesis is easy, the storage stability of the composition is not impaired, and a high crosslinking reaction rate and thus a high curing rate are considered, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, It is preferable to use vinyltrimethoxysilane, methyltris (isopropenoxy) silane, vinyltris (isopropenoxy) silane and partial hydrolysis condensates thereof. Examples of the effects of the present invention that are notable include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, and vinyltrimethoxysilane.

  The amount of the crosslinking agent is usually 0.5 to 25 parts by weight, preferably 2 to 10 parts by weight with respect to 100 parts by weight of component (A2). If the amount is less than 0.5 part by weight, crosslinking is not sufficiently performed, and not only a cured product having low hardness is obtained, but also the storage stability of the composition containing the crosslinking agent is poor. On the other hand, when it exceeds 25 parts by weight, a part of it is separated from the system during storage, causing significant shrinkage during curing, and the physical properties of the resulting rubbery elastic body are lowered.

  In the case where the component (A) is a component having a hydrolyzable group (X) as described above (A1) and b exceeds an average of 1, as described above, the curing is basically performed without a crosslinking agent. Even in such a case, in order to realize a good balance between the curability of the composition and the mechanical properties of the rubber-like elastic body obtained by curing, the above crosslinking agent may be used in combination. It is more preferable to use a crosslinking agent in which the hydrolyzable group Y is the same as X. The compounding amount of the crosslinking agent in this case is usually 0.1 to 25 parts by weight, preferably 0.3 to 10 parts by weight with respect to 100 parts by weight of component (A1). If the amount exceeds 25 parts by weight, the phenomenon described above is unfavorable.

In the present invention, in addition to the silicon functional compound having a monovalent hydrocarbon group as R ⁶ as enumerated above, specific examples of carbon functionalities having a substituted monovalent hydrocarbon group are the same. The compound may be used as part or all of the crosslinker. Examples of such R ⁶ include substituted amino groups, epoxy groups, isocyanato groups, (meth) acryloxy groups, mercapto groups, alkyl groups substituted with halogen atoms, and phenyl groups. Examples of the substituted alkyl group include a substituted methyl group, a 3-substituted propyl group, and a 4-substituted butyl group, but a 3-substituted propyl group is preferable because of easy synthesis.

Examples of such a compound having R ⁶ include N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, and N-methyl-3. Substituted amino group-containing silanes such as aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N, N-dimethyl-3-aminopropyltrimethoxysilane; 3-glycidoxytrimethoxysilane; Epoxy group-containing silanes such as 3-glycidoxymethyldimethoxysilane and 3,4-epoxycyclohexylethyltrimethoxysilane; 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane-containing isocyanato groups Silane; 3-acryloxypropylto Methoxysilane, 3-methacryloxypropyltrimethoxysilane, (meth) acryloxy group-containing silane such as 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane; 3-mercaptopropyltrimethoxysilane Illustrative examples include mercapto group-containing silanes; and halogen atom-containing silanes such as 3-chloropropyltrimethoxysilane. Of these, epoxy group-containing silanes and isocyanato group-containing silanes, which have little influence on the curing catalyst, are more preferable. More preferred are isocyanurate compounds such as tri (N-trimethoxysilylpropyl) cyclotriisocyanurate, mixtures / reactants of amino group-containing silane and epoxy group-containing silane, and the like.

  Such substituted hydrocarbon group-containing silanes and the above-mentioned vinyl group-containing silanes are carbon-functional silanes, and by adding them, the adhesion to various substrates when the composition is cured is improved. be able to.

  The compounding amount of such a carbon-functional silane is preferably 0.05 to 25 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the component (A). If it is less than 0.05 parts by weight, the effect of improving the adhesiveness is small, and the expression is slow. On the other hand, when the amount exceeds 25 parts by weight, in addition to the above-mentioned problems, storage stability and workability deteriorate, and yellowing occurs.

  The inorganic filler of the component (B) of the present invention includes silicon dioxide powder such as calcium carbonate and quartz powder, zinc oxide such as titanium oxide and zinc white, magnesium oxide, zinc carbonate, basic zinc carbonate, magnesium carbonate and alumina. Examples thereof include boron nitride such as aluminum oxide, aluminum hydroxide, kaolin and boron nitride, clay, calcined clay, mica and the like. Examples of calcium carbonate include heavy calcium carbonate, precipitated calcium carbonate (light calcium carbonate), and each surface-treated calcium carbonate. Examples of the surface treating agent include resin acids, resin acid metal soaps, fatty acids, fatty acid metal soaps, fatty acid esters, acrylic acid polymers, hydrocarbon polymers such as polypropylene, and the like. The component (B) acts to impart high mechanical strength required when used as, for example, a sealing material, an adhesive, an in-situ molded gasket, etc., to the rubber-like elastic body obtained from the composition of the present invention.

  The blending ratio of the inorganic filler which is the component (B) of the present invention to the component (A) is, for example, usually 5 to 200 parts by weight, preferably about 20 to 200 parts by weight, per 100 parts by weight of the component (A). Is good. If it is less than 5 parts by weight, sufficient extrudability, high thixotropy and slump resistance may not be imparted. On the other hand, if it exceeds 200 parts by weight, the viscosity becomes too high and workability may be significantly reduced. .

  In the present invention, the curing catalyst for component (C) reacts with X contained as a crosslinking means for component (A) and / or component X and component X for crosslinking agent in the presence of moisture. It is a curing catalyst for forming a rubbery elastic body by forming a crosslinked structure. In general, carboxylic acid metal salts, organotin compounds, alkoxy titaniums, organoaluminum, organozirconium compounds, and the like have been used as curing catalysts for room temperature curable organopolysiloxane compositions. From the viewpoint of recent environmental considerations and adhesion to difficult-to-adhere members, (C) component IVB group IVB alkoxy metal compounds such as alkoxy titaniums and organic zirconium compounds, especially alkoxy titanium chelates are widely used as curing catalysts. Although it has been used, as described above, it has problems such as resin quality.

  In this invention, such a problem is solved by mix | blending the curing catalyst represented by following General formula (1) as a titanium-type catalyst.

(Wherein R ¹ and R ² represent a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other, X is a chelate group, a is a number from ¹ to ^3. n Is a number that makes the viscosity of the component (C) at 23 ° C. 10 to 100,000 cP.)
From the viewpoint of workability when producing the composition, the viscosity of the component (C) is preferably 10 to 10,000 cP, more preferably the viscosity of the component (C) from the viewpoint of the catalytic activity and the effect of the present invention. 20 to 5,000 cP.

  Examples of such compounds include α, ω-bis [isopropoxydi (ethylacetoacetate) titanoxy] dimethylpolysiloxane, α, ω-bis [isopropoxydi (acetoacetate) titanoxy] dimethylpolysiloxane, α, ω- Bis [diisopropoxy (ethyl acetoacetate) titanoxy] dimethylpolysiloxane, α, ω-bis [diisopropoxy (acetoacetate) titanoxy] dimethylpolysiloxane, α, ω-bis [butoxydi (ethylacetoacetate) titanoxy] dimethyl Polysiloxane, α, ω-bis [n-propoxydi (ethylacetoacetate) titanoxy] dimethylpolysiloxane, α, ω-bis [isopropoxydi (ethylacetoacetate) titanoxy] dimethylpolysiloxane, α, ω-bis [iso Propoxyji (Buchi Ruacetoacetate) titanoxy] dimethylpolysiloxane, α, ω-bis [isopropoxydi (octylacetoacetate) titoxy] dimethylpolysiloxane, α, ω-bis [isopropoxydi (ethylacetoacetate) titanoxy] polymethylvinylsiloxane Etc. are exemplified.

  Such a component (C) can be obtained by reacting the α, ω-dihydroxypolydimethylsiloxane with alkoxytitanium and then exchanging β-diketones with alkoxy of alkoxytitanium. Alternatively, it can be obtained by reacting the α, ω-dihydroxypolydimethylsiloxane with an alkoxytitanium chelate. In the reaction, it is possible to promote the reaction by heating, but if the temperature is too high, the thickening and discoloration proceed, which is not preferable. In the reaction, alcohols are preferably used as a reaction buffer. Furthermore, it is preferable from the active surface of the curing catalyst that the alcohol used as a buffering agent and the alcohol as a reaction byproduct are distilled off after the completion of the reaction and removed from the system.

  The blending amount of such component (C) is 0.01 to 30 parts by weight, preferably 0.05 to 15 parts by weight per 100 parts by weight of component (A). If it is less than 0.01 parts by weight, it does not act sufficiently as a curing catalyst and not only takes a long time to cure, but also the curing in the deep part of the rubber layer far from the contact surface with air becomes insufficient, on the contrary, 30 parts by weight. In the case of exceeding the part, there is no effect commensurate with the blending amount, which is meaningless and economically disadvantageous.

  The room temperature curable organopolysiloxane composition of the present invention is a pigment, a thixotropic agent, a viscosity modifier for improving extrusion workability, an ultraviolet absorber, a fungicide, a heat resistance improver, depending on the purpose. Various additives such as a flame retardant may be added.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to a following example. In the examples, “part” means “part by weight”, and all physical properties such as viscosity are values at 23 ° C. and relative humidity 50%.

Further, in the following Examples and Comparative Examples, the following measurements / evaluations were performed on the polyorganosiloxane compositions prepared, sealed and stored.
(A) Drying time of finger touch: After extruding the composition in an atmosphere of 23 ° C. and 50% RH, the time to contact the surface with a finger and confirm that it was in a dry state was measured.
(B) Physical characteristics: A sheet obtained by extruding the composition into a sheet having a thickness of 6 mm is left standing at 23 ° C. and 50% RH for 168 hours to be cured by moisture in the air. The characteristics were measured according to JIS K6301 on both the upper side (surface in contact with air) and the lower side (sheet plate surface: coated surface) of the sheet-like cured product. At that time, the surface state of the cured product was confirmed.
(C) Storage stability: The composition was put in a container where moisture was cut off, heated at 50 ° C. for 14 days, and then the touch drying time was measured in an atmosphere of 23 ° C. and 50% RH. Further, it was extruded into a sheet having a thickness of 2 mm, which was left standing at 23 ° C. and 50% RH for 168 hours and cured by moisture in the air, and the physical properties of the cured product were determined in accordance with JIS K6301 in the same manner as (b) above. It was measured.
(D) Adhesiveness: The composition was applied on a flat plate of various adhesive members having a width of 25 mm and a length of 80 mm, a shear adhesion test specimen was produced with a stacking width of 10 mm, and left for 168 hours at 23 ° C. and 50% RH. After being cured by moisture in the air, its adhesive strength and cohesive failure rate were measured.
(E) H type physical properties: Adhesive strength and cohesive failure rate were measured according to the method described in JIS A 1439 (1992 version). At that time, the adhesive interface and the surface state of the cured product at the part where the adherend and the air contacted were observed. Moreover, after immersing the adherend after measurement in hot water at 50 ° C. for 4 days, the surface state of the cured product was observed.
Synthesis example 1
A three-necked flask equipped with a stirrer, a cooling tube, and a nitrogen introducing tube was degassed with nitrogen, and then 640 g of tetraisopropoxytitanium was added to start stirring. 586 g of ethyl acetoacetate was slowly added at a rate of about 10 g per minute so that the flask contents did not exceed 65 ° C. At that time, ice water was prepared for cooling in case the temperature was too high. After adding ethyl acetoacetate, it was heated to about 60 ° C. with a mantle heater and continued to heat until the contents turned yellow. Thereafter, the mixture was cooled to room temperature, 1126 g of α, ω-dihydroxydimethylpolysiloxane having a kinematic viscosity of 20 cSt was added at a rate of about 75-100 g per minute, and stirring was continued for about 1 hour. Then, it heated to 55 degreeC and the isopropanol which is a reaction by-product was distilled off. After the distillation, the reaction product was taken out into a container cooled to room temperature and degassed with nitrogen. Curing catalyst A, a viscous light brown transparent liquid having a viscosity of about 240 cP, was obtained with 2186 g.
Spectral analysis results / infrared absorption
2930,2860,2840cm ^-1 [ CH _{3 -} CH ₂ , -CH _2- , CH _3- ], 1730,1650 cm ^-1 [ -C (= O) -CH _2- (C = O) -,-C ( OH) = CH- C (= O) -],
1620cm ^-1 [-(OH) C = CH -C (= O)-],
1440cm ^-1 [ CH ₃ -C (= O)-], 1250cm ^-1 [ CH ₃ -Si-],
1150cm ^-1 [CH ₂ - O -C)-], 1090-1020cm ^-1 [ Si-O -Si-],
Confirmed disappearance of 3600-3100cm ^-1 [Si-OH] NMR
_{Si-C H 3; 0.2ppm,} C H 3 - CH 2; 1.3ppm, C H 3 -C (= O) -: 2.2ppm, C H 3 CH 2 OC (= O); 4.1ppm
-C (= O) C H ₂ C (= O) O-; 3.4ppm
Si-C H ₃ ; 5.2ppm , C H _3- CH _2- O-; 14.1ppm, C H ₃ -C (= O)-: 29.7ppm,
CH ₃ C H ₂ OC (= O); 61.1ppm
Synthesis example 2
A three-necked flask equipped with a stirrer, cooling tube, and nitrogen introduction tube was degassed with nitrogen, and then 1090 g of light yellow transparent diisopropoxy titanium bis (ethylacetoacetate) was added, and 140 g of isopropanol was further added, and stirring was started. did. Thereafter, 1100 g of α, ω-dihydroxydimethylpolysiloxane having a kinematic viscosity of 18 cSt was added at a rate of about 75-100 g per minute, and stirring was continued for about 1 hour. Then, it heated to 55 degreeC and isopropanol which is a buffer in reaction was distilled off. After the distillation, the reaction product was taken out into a container cooled to room temperature and degassed with nitrogen. 2117 g of an orange-colored curing catalyst B, a viscous transparent liquid having a viscosity of about 197 cP, was obtained.
Spectral analysis results / infrared absorption
_{^{2860,2840cm -1 [- CH 2 -,}} CH 3 -], 1690cm -1 [- C (= O) -CH 2 - (C = O) -, - C (OH) = CH- C (= O) -],
1620cm ^-1 [-(OH) C = CH -C (= O)-],
1430cm ^-1 [ CH ₃ -C (= O)-], 1250cm ^-1 [ CH ₃ -Si-], 1090-1020cm ^-1 [ Si-O -Si-],
Confirmed disappearance of 3600-3100cm ^-1 [ Si- OH] NMR
_{Si-C H 3; 0.2ppm,} C H 3 - CH 2; 1.3ppm, C H 3 -C (= O) -: 2.2ppm, C H 3 CH 2 OC (= O); 4.1ppm
-C (= O) C H ₂ C (= O) O-; 3.4ppm
Si-C H ₃ ; 5.2ppm , C H _3- CH _2- O-; 14.1ppm, C H ₃ -C (= O)-: 29.7ppm,
CH ₃ C H ₂ OC (= O); 61.1ppm
Example 1
100 parts of α, ω-dihydroxydimethylpolysiloxane having a viscosity of 40,000 cP, 120 parts of precipitated calcium carbonate having a primary particle diameter of 0.07 μm and surface-treated with 2.3% rosin acid as a filler, average particle diameter 30 parts of heavy calcium carbonate having a viscosity of 3.0 μm and 45 parts of methyl silicone oil having a viscosity of 100 cP were added and mixed uniformly. Next, 4.5 parts of methyltrimethoxysilane, 0.8 part of tri (N-trimethoxysilylpropyl) cyclotriisocyanurate and 7.5 parts of the curing catalyst A prepared in Synthesis Example 1 were added, It mixed uniformly and the polyorganosiloxane composition 1 was obtained.
Comparative Example 1
Comparative composition 1 was obtained in the same manner as in Example 1 except that 2.5 parts of diisopropoxybis (ethyl acetoacetate) titanium was blended in place of curing catalyst A used in Example 1.
Example 2
100 parts of α, ω-bis (methyldimethoxysiloxy) dimethylpolysiloxane having a viscosity of 24,000 cP, 120 parts of calcium carbonate having a primary particle diameter of 0.05 μm and surface-treated with 4.5% glycerol stearate, average particle diameter Of 30 μm heavy calcium carbonate and 45 parts methyl silicone oil having a viscosity of 100 cP were added and mixed uniformly. Next, 2.5 parts of methyltrimethoxysilane, 0.8 part of tri (N-trimethoxysilylpropyl) cyclotriisocyanurate, and 7.0 parts of curing catalyst A are added, and mixed uniformly while blocking moisture. An organosiloxane composition 2 was obtained.
Comparative Example 2
Comparative composition 2 was obtained in the same manner as in Example 2, except that 2.4 parts of diisopropoxybis (ethyl acetoacetate) titanium was used instead of curing catalyst A used in Example 2.
Example 3
100 parts α, ω-bis (methyldimethoxysiloxy) dimethylpolysiloxane having a viscosity of 30,000 cP, 100 parts of crystallite 5X (average particle diameter of 1.4 μm) as a quartz powder, and Typaque A-100 (a titanium oxide) 20 parts of Ishihara Sangyo Co., Ltd.), 2 parts of an amide wax and 35 parts of methyl silicone oil having a viscosity of 100 cP were added to the thixotropic agent and mixed uniformly. Next, 3.0 parts of methyltrimethoxysilane, 0.8 part of tri (N-trimethoxysilylpropyl) cyclotriisocyanurate and 7.0 parts of curing catalyst B are added and mixed uniformly under moisture blocking. An organosiloxane composition 3 was obtained.
Comparative Example 3
Comparative composition 3 was obtained in the same manner as in Example 3, except that 2.2 parts of diisopropoxybis (ethyl acetoacetate) titanium was used instead of curing catalyst B used in Example 2.

  The results of evaluating these compositions are shown in Table 1.

  As shown in the examples and comparative examples, the catalyst component migrates to the surface of the cured product during curing, and the surface of the cured product is resinized by accelerating curing of the catalyst itself and curing of the crosslinking component at the surface and adhesion interface. Therefore, it is possible to provide a composition that does not cause a phenomenon such as causing a difference in hardness from the inside of the cured product and a problem such that peeling is likely to occur in an area close to an interface, particularly a portion in contact with air.

Claims (2)

(A) (A1) having a viscosity at 23 ° C. of 20 to 1,000,000 cP, silicon functional polydiorganosiloxane having an average number of hydrolyzable groups exceeding 2 as silicon functional groups, and / or (A2) a room temperature curable organopolysiloxane composition comprising a silicon functional polydiorganosiloxane having two or more silicon functional groups in the molecule and a crosslinking agent,
With respect to 100 parts by weight of the (A) polydiorganosiloxane,
(B) Inorganic filler 5 to 200 parts by weight (C) A room temperature-curable organopolysiloxane comprising 0.01 to 30 parts by weight of a curing catalyst represented by the following general formula (1) Composition.

(Wherein R ¹ and R ² represent a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different from each other, X is a chelate group, a is a number from ¹ to ^3. n Is a number that makes the viscosity of the component (C) at 23 ° C. 10 to 100,000 cP.) The room temperature-curable organopolysiloxane composition according to claim 1, wherein the component (B) is one or more inorganic fillers selected from calcium carbonate, silicon dioxide powder and titanium oxide.