JP2550749C - - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a curable silicone composition which cures to an elastomer or gel and a cured product thereof, and more specifically to low elasticity / low hardness or high elongation. The present invention relates to a condensation-type curable silicone composition which hardly bleeds, bleeds or separates oil during use, and is preferably used as a tampo material or a high elongation sealant, and a cured product thereof. [Conventional Techniques and Problems to be Solved by the Invention] Conventionally, condensation-curable silicone compositions have been used for architectural sealants, food display models, tampon printing materials, potting agents, and the like. In these applications, for example, high elongation and low elasticity / low hardness are often required, for example, high elongation is required for building sealants, and low elasticity / low hardness is required for tampo printing materials. . As a technique for meeting the demand for these condensation type silicone compositions, conventionally, a method of diluting the condensation type silicone composition with a non-reactive silicone oil or a method of adding various plasticizers has been adopted. I have. However, although these methods have a certain effect on high elongation, low elasticity and low hardness, they may adhere to dirt, bleed or separate oil over a long period of use, Improvements in the drawbacks are desired. The present invention has been made in view of the above circumstances, and has a low elasticity and low hardness or a high elongation rate by being cured into an elastomer or a gel state, and a condensation type that gives a cured product with as little oil bleeding and separation as possible. An object of the present invention is to provide a curable silicone composition and a cured product of the composition. [Means and Actions for Solving the Problems] The present inventors have made intensive studies to achieve the above object, and as a result, as a main component of the condensation-curable silicone composition, (A) the following general formula (I) (Where R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ¹ is an alkyl group or an alkoxy-substituted alkyl group having 1 to 4 carbon atoms, and Q ₁ and Q ₂ are A divalent hydrocarbon group or an oxygen atom of 1 to 8, a is 2 or 3, and l is an integer of 5 to 3000.) A diorganopolysiloxane having both ends capped with an alkoxysilyl group, ) The following general formula (II) (Wherein, R represents the same meaning as described above, and m is an integer of 5 to 3000.) One or both of diorganopolysiloxanes whose both terminals are blocked with a hydroxysilyl group are represented by the following formula: (C) The following general formula (III) (Wherein, R, R ¹ , Q ₂ and a have the same meaning as above, and R ² has 1 to 1 carbon atoms)
8 is an alkyl group, a cycloalkyl group or an aryl group, and Q ₃ has 1 to 8 carbon atoms.
Is a divalent hydrocarbon group. n is an integer that makes the viscosity at 25 ° C. 800 cp or more, and the upper limit is 3000. It has been found that it is effective to use a diorganopolysiloxane in which one end represented by is blocked with an alkoxysilyl group and the other end is a tri (hydrocarbono) silyl group. That is, when the composition is obtained by combining the diorganopolysiloxane of the component (A) and the component (C), a one-part moisture-curable composition having a high elongation rate can be obtained, and (B)
When a composition comprising the component (C) and the diorganopolysiloxane of the component (C) is used, a composition giving a gel-like cured product can be obtained. Further, the components (A), (B) and (C) can be obtained. When a composition is obtained by combining the diorganopolysiloxane of the present invention, for example, a composition that provides a low-elasticity / low-hardness elastomer suitable for a tampo material or the like can be obtained.The composition of the present invention has a low elasticity / low-hardness. Alternatively, a high-elongation elastomer or gel-like cured product is provided, and it has been found that all of these cured products have extremely little oil bleeding and separation, and the present invention has been accomplished. Accordingly, the present invention relates to a method of preparing a polymer (C) comprising one or both of the components (A) and (B).
The present invention provides a condensation-type curable silicone composition comprising the component diorganopolysiloxane and a curing catalyst, and a cured product of the composition. Hereinafter, the present invention will be described in more detail. The curable silicone composition of the present invention has the following general formula (I) as component (A): And a diorganopolysiloxane having both ends capped with a dialkoxysilyl group or trialkoxysilyl group and a component (B) represented by the following general formula (II): Wherein one or both of diorganopolysiloxanes whose both terminals are blocked with a hydroxysilyl group are used. Here, in the above formula (I), R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, specifically, an alkyl group such as a methyl group, an ethyl group or a propyl group, a cyclohexyl group, or the like. Cycloalkyl group, vinyl group, allyl group, alkenyl group such as isopropenoxy group, phenyl group, aryl group such as tolyl group, or 3,3
Examples thereof include groups in which a hydrogen atom of such a group is partially substituted with a halogen atom or the like, such as a 3-trifluoropropyl group, a chloromethyl group, and a 3-chloropropyl group.
R ¹ is an alkyl group having 1 to 4 carbon atoms or an alkoxy-substituted alkyl group;
Specific examples include a methyl group, an ethyl group, an n- or i-propyl group, an n-, sec- or t-butyl group, a β-methoxyethyl group, a β-ethoxyethyl group, and the like. The alkoxy groups at both ends in the above are methoxy, ethoxy, n- or i-propoxy, n-, sec- or t-butoxy, β-methoxyethoxy, β-ethoxyethoxy and the like. Q ₁ and Q ₂ each have 1 to 8 carbon atoms.
And specific examples of the divalent hydrocarbon group having 1 to 8 carbon atoms include an alkylene group, an alkenylene group, an arylene group, and an alkylarylene group. Here, l is an integer of 5 to 3000, preferably 50 to 1000, and a is 2 or 3. The method for synthesizing the diorganopolysiloxane of the formula (I) is described in, for example,
According to the description in JP-A-207383, the following formula (i) (Wherein, R and l have the same meanings as described above). A diorganopolysiloxane having both ends capped with a vinyl group represented by the following formula (ii): (Wherein, R ¹ and a have the same meanings as described above) by adding a silane such as trimethoxysilane or dimethoxymethylsilane by a hydrosilylation reaction using a platinum catalyst. it can. The diorganopolysiloxane of the formula (I) obtained by such a reaction includes the following. (Wherein, R and l have the same meanings as above, and Me represents a methyl group.) As another method for synthesizing the diorganopolysiloxane of the above formula (I), the following formula (iii) (Wherein, R and l have the same meanings as described above.) A diorganopolysiloxane having both ends capped with a hydroxysilyl group is represented by the following formula (iv): (Wherein, R and R ¹ have the same meanings as described above, and b is 3 or 4.) trifunctional or tetrafunctional alkoxysilane represented by the following formula, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane Calcium hydroxide under heating, tetrabutoxysilane, tetra (methoxyethoxy) silane, tetra (ethoxyethoxy) silane, methyltrimethoxysilane, methyltriethoxysilane, methyltri (methoxyethoxy) silane, methyltri (ethoxyethoxy) silane, etc. Can be obtained by a condensation reaction in the presence of an alkaline earth metal hydroxide or the like. The following are examples of the diorganopolysiloxane of the formula (I) obtained by such a reaction. (In the formula, R, l, and Me have the same meanings as described above.) On the other hand, the diorganopolysiloxane represented by the above formula (II) whose both ends are blocked with a hydroxysilyl group contains water or silanol. It can be easily obtained by a known method in which a diorganocyclopolysiloxane is equilibrated with an alkali catalyst or an acid catalyst using a compound as a terminator. In the formula (II), m is an integer of 5 to 3000, preferably 10 to 1000. Next, the following general formula (III) of the component (C) The diorganopolysiloxane of which one end is blocked with an alkoxysilyl group is an essential component of the condensation-curable silicone composition of the present invention, and by adding this component, a low elastic modulus, a low hardness, and a high elongation are obtained. And free silicone oil can be reduced. This is presumably because, when the oil having a functional group only at one end is cured, the oil is incorporated into the cross-link while the one end is free, so that the cross-link density does not increase, and therefore the hardness does not increase. In the above formula, R, R ¹ , and Q ₂ have the same meanings as described above, and n is an integer of 5 to 3000. A preferred range is an integer that makes the viscosity at 10 to 25 ° C. 800 or more, The upper limit is 3000, preferably 1000. R ² is an alkyl group, cycloalkyl group or aryl group having 1 to 8 carbon atoms, Q ₃ is a divalent hydrocarbon group having 1 to 8 carbon atoms, and specific examples of these R ² and Q ₃ are The same ones as described for R, Q ₁ and Q ₂ can be mentioned. The method for synthesizing the diorganopolysiloxane represented by the formula (III) is basically the same as the method for synthesizing the diorganopolysiloxane represented by the formula (I), and there are several methods. For example, by subjecting a diorganopolysiloxane having a terminal blocked with a vinyl group and a trialkylsilyl group to a hydrosilation reaction of a silane represented by the above formula (ii) using a platinum catalyst, for example, the following formula (II)
A diorganopolysiloxane such as Ia) can be obtained. (In the formula, R, R ³ , n and Me have the same meanings as described above.) The polymer having a dimethylvinylsilyl group at one end serving as a raw material for the reaction is, for example, trimethylsiloxylithium as an initiator. As 1,3,5-tris (
Heat a cyclic siloxane trimer such as (3,3,3-trifluoropropyl) trimethylcyclotrisiloxane or hexamethylcyclotrisiloxane or compare in the presence of a polar solvent such as tetrahydrofuran, dimethylsulfoxide and dimethylformamide It is obtained by ring-opening polymerization at a relatively low temperature and neutralizing with dimethylvinylchlorosilane. Further, a five-coordinate silicon compound as described in JP-B-45-1070 using trimethylhydroxysilane as an initiator,
For example In the presence of a polar solvent such as acetonitrile in a temperature range of 0 to 100 ° C., using 1,3,5-tris (3,3,3) with trimethylsiloxylithium as an initiator.
It is obtained by subjecting a cyclic siloxane trimer such as (3-trifluoropropyl) trimethylcyclotrisiloxane or hexamethylcyclotrisiloxane to ring-opening polymerization and neutralizing with dimethylvinylchlorosilane. Further, the siloxane polymer blocked with a dimethylvinylsilyl group at one end, which is a raw material of the diorganopolysiloxane represented by the formula (III), is obtained by the above-described synthesis method capable of quantitatively obtaining one end. Not only CH ₂
An average one-terminal oil obtained by equilibration of octamethylcyclotetrasiloxane with an alkali catalyst or an acid catalyst having CH (R ₂ ) SiO _1/2 and R ₃ SiO _1/2 as terminal groups is also used. It is possible. The compounding amounts of the components (A), (B), and (C) are based on the total amount of these components.
The component (A) and the component (B) are each 0 to 90% (% by weight, the same applies hereinafter).
The total amount of the component and the component (B) is preferably 25 to 90%, and the content of the component (C) is preferably 10 to 75%. That is, as described above, the curable silicone composition of the present invention is obtained by adding the component (C) to one or both of the components (A) and (B). By forming a composition combining the component and the component (C), a one-pack moisture-curable composition having a high elongation can be obtained, and a composition combining the component (B) and the component (C). By obtaining a cured product, a composition that becomes a gel-like cured product can be obtained. Further, by combining the three components (A), (B) and (C), the composition is suitably used as a tampo material or the like. The composition can be used to give a cured product having a low hardness to be used, and the curable silicone composition of the present invention can be applied to various uses by combining these components. In this case, the components (A) and (
When the component (C) is combined with the component (A), the ratio of the component (A) to the component (C) is preferably from 90 to 25:10 to 75 by weight, and the component (B) and the component (C) are combined. In the above, the ratio between the component (B) and the component (C) is 9 by weight.
It is preferably 0 to 25:10 to 75, and when the three components (A), (B) and (C) are combined, the total amount of the components (A) and (B) is The ratio with the component (C) is also preferably 90 to 25:10 to 75 by weight. The condensation-type curable silicone composition of the present invention may contain a curing catalyst for curing the above-mentioned diorganopolysiloxane component. The curing catalyst is generally used for condensation-type silicone RTV. Metal salts of organic acids such as dibutyltin dilaurate, dibutyltin dibenzylmalate, dibutyltin dioctoate, iron stearate, lead octylate, titanates such as tetraisopropyl titanate, titanium acetylacetonate, etc. And a mixture thereof. When the amount is too small, the function as a curing catalyst is not sufficiently exhibited, and the curing time is prolonged, and the curing at the deep part of the rubber layer may be insufficient. (A), (B), (C) because the heat resistance may deteriorate and the heat resistance after curing may decrease.
The amount is preferably in the range of 0.01 to 10 parts by weight, and particularly preferably in the range of 0.1 to 5 parts by weight, based on 100 parts by weight of the total components. Further, fumed silica, sedimentable silica, and their hydrophobized substances for the purpose of improving the properties of the composition of the present invention, further reinforcing fillers, sedimentation inhibitors, and carbon black for the purpose of electrical conductivity can be blended. In addition, quartz powder, fused quartz, spherical silica, diatomaceous earth, zeolite, calcium carbonate, titanium dioxide, iron oxide, alumina, spherical alumina, aluminum hydroxide, aluminum nitride, magnesium sulfate, etc. are semi-reinforcing fillers, extenders, heat Lead compounds such as lead, lead carbonate and lead hydroxide are used for the purpose of conductive filler and for the purpose of radiation shielding and the like. Further, since the composition of the present invention is a condensation-curing type, water or alcohols (methanol, ethanol, propanol, methyl cellosolve, etc.) may be added for the purpose of accelerating the curing or improving the deep curing. Is optional. In addition, as long as the object of the present invention is not impaired, a coloring agent such as an inorganic pigment or an organic dye, and a heat-resistant or flame-retardant improver such as cerium oxide, zinc carbonate, manganese carbonate, benzotriazole, or a platinum compound can be added. is there. In the case where a tack appears on the cured surface of the composition of the present invention, various silanes such as trimethoxysilane, triethoxysilane, tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane, or a hydrolyzate thereof are appropriately used. It is possible to add and eliminate this, but if it is added in a large amount, the characteristics of the present invention such as low elasticity, low hardness and high elongation cannot be obtained. It is preferable to use 0.05 to 2 parts by weight based on 100 parts by weight of the total amount of the component (A), the component (B) and the component (C). The curable silicone composition of the present invention can be suitably used as a one-part or two-part type by mixing the above-mentioned components as a one-part or two-part sealant for building sealants, food display models, tampon printing materials, potting agents, and the like. [Effects of the Invention] As described above, the curable silicone composition of the present invention provides an elastomer or gel-like cured product having low elasticity, low hardness or high elongation by selecting the components, and uses oil when used. Since bleeding and separation hardly occur, these oils are suitably used as tampo materials and sealants in which bleeding and separation of these oils are problematic, and have a wide range of uses. Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. [Examples 1, 2 and Comparative Examples] Dimethylpolysiloxane shown below and the components shown in Table 1 were mixed in the amounts shown in the same table to prepare compositions, and these compositions were prepared at 20 ° C / 50%. Cured under RH conditions for 7 days. The hardness, elongation and tensile strength of the obtained cured product were measured. The measurement results are also shown in Table 1. Dimethylpolysiloxane (III-1) The following general formula (S is an integer and the viscosity at 25 ° C. is 800 cp) dimethylpolysiloxane (I-1) (T is an integer and the viscosity at 25 ° C. is 20,000 cp)

Claims (1)

[Claims] 1. A curable silicone composition comprising one or both of the following components (A) and (B) and the following component (C) as main components: (A) The following general formula (I) (Where R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R ¹ is an alkyl group or an alkoxy-substituted alkyl group having 1 to 4 carbon atoms, and Q ₁ and Q ₂ are A diorganopolysiloxane represented by the following general formula (II): 1 to 8 divalent hydrocarbon groups or oxygen atoms, a is 2 or 3, and l is an integer of 5 to 3000. (Wherein, R has the same meaning as described above, and m is an integer of 5-3000). (C) a diorganopolysiloxane represented by the following general formula (III): (Wherein, R, R ¹ , Q ₂ and a have the same meaning as above, and R ² has 1 to 1 carbon atoms)
8 is an alkyl group, a cycloalkyl group or an aryl group, and Q ₃ has 1 to 8 carbon atoms.
Is a divalent hydrocarbon group. n is an integer that makes the viscosity at 25 ° C. 800 cp or more, and the upper limit is 3000. A diorganopolysiloxane represented by the formula: 2. A cured product obtained by curing the curable silicone composition according to claim 1.