JP6047351B2 - Silicone composition - Google Patents

Description

  The present invention relates to a silicone composition that can be used for, for example, a protective film used in high heat resistance applications.

  In general, in the case of an epoxy resin or an epoxy mold resin often used for electronic parts and the like, this type of silicone composition has excellent adhesion and is convenient to use, but the internal carbon-carbon bond is broken and carbonized. Therefore, it cannot be said that the heat resistance is high, and the heat resistance is only about 155 ° C. in continuous use. Moreover, even if it is a polyimide resin using an imide bond, the heat resistance in continuous use is only about 200 degreeC.

  On the other hand, silicone rubber using a siloxane bond generally has higher heat resistance than epoxy and polyimide, but depending on the type of functional group in the side chain, it is difficult to use because it carbonizes in a high temperature environment.

  In addition, many of the silicone rubbers are likely to leave unreacted components inside, and since the curing proceeds with long-term use at high temperatures, the flexibility is lost or the unreacted components are carbonized and discolored. It is difficult to use. In addition, unreacted low-molecular-weight siloxane compounds from the silicone cured product volatilize and scatter around, causing a strong odor during use and insulating electrical contacts. .

  Also, in applications that require heat resistance, it is not only kept at high temperature for a long period of time, but also drops to room temperature or lower, so it is protected with ceramics, metals, and other materials A difference in thermal expansion between the resin and the material is likely to occur, and there is a possibility that cracking or peeling may occur due to the difference in expansion coefficient, and it is necessary to absorb this difference in expansion coefficient.

  Conventionally, silicone rubber has been used as an electronic component of this type and as a heat-resistant resin material that is a semiconductor sealing material under high temperature use. An organic-inorganic hybrid resin is used.

<Patent Document 1>
And the prior art of this kind of organic-inorganic hybrid material is disclosed by patent document 1. FIG. The organic / inorganic hybrid material disclosed in Patent Document 1 is prepared by reacting a metal alkoxide with a solution of an organosilicon compound such as terminal silanol-type polydimethylsiloxane to prepare a sol solution, and heating the sol solution. Manufactured. Further, in Patent Document 1, an organosilicon compound solution having a functional group capable of reacting with a metal alkoxide at both ends or one end is heat-treated to remove moisture and low molecular weight components, and the heat-treated organosilicon compound solution An organic / inorganic hybrid sol solution is prepared by dropping a metal alkoxide into the solution, and the sol solution is heated to gel to produce an organic / inorganic hybrid.

  Here, the organic / inorganic hybrid disclosed in Patent Document 1 is a hybrid sol in which silicone is cross-linked by reaction of an organic compound whose end is silanolated with a metal alkoxide, and a flexible material is obtained. However, the heat resistance at 200 ° C. is 0.5 hours, or the heat resistance at 300 ° C. is 0.2 hours. It does not have sufficient “heat resistance” in practice.

<Patent Document 2>
Furthermore, in the organic-inorganic hybrid material disclosed in Patent Document 2, organosilicon alkoxide polymer and titanium alkoxide are used as the inorganic skeleton component, terminal silanol-type dialkylsiloxane is used as the organic skeleton component, and silicone rubber powder and silicone are used as the flexible component. It is a composition using oil. In particular, in Patent Document 2, since the reactivity of the inorganic skeleton component is too high, the crosslinking points become dense and the cured product hardness increases. And in this patent document 2, as a countermeasure against an increase in the hardness of the cured product, although a flexible component is mixed to provide flexibility, since this flexible component does not contribute to crosslinking, it is not exposed to high temperatures. Not functioning effectively for weight loss.

<Patent Document 3>
In the organic / inorganic hybrid composition disclosed in Patent Document 3, a metal alkoxide mixture obtained by adding high-reactivity metal alkoxide B to low-reactivity metal alkoxide A and polyorganosiloxane are used as hydrolysis catalysts. It is obtained by performing a condensation reaction without using a reaction accelerator after hydrolysis. However, in the organic-inorganic hybrid composition disclosed in Patent Document 3, the heat resistance is evaluated for appearance, light transmittance, and tensile strength before and after high-temperature exposure treatment when heated at 200 ° C. for 60 hours. Stays.

<Patent Document 4>
Furthermore, the hybrid composition disclosed in Patent Document 4 is obtained by a hydrolysis reaction and a condensation reaction of a mixture having a silicate compound and a polydimethylsiloxane having a terminal silicate-modified, and does not contain a low molecular siloxane. A manufacturing method is described. However, the hybrid composition obtained by the production method described in Patent Document 4 has not been evaluated for the low molecular weight generated from the cured product when exposed to a high temperature of 250 ° C. or higher.

<Patent Document 5>
The organic-inorganic hybrid material disclosed in Patent Document 5 is produced by polydimethylsiloxane, a metal and / or metalloid alkoxide, and a dehydration polycondensation reaction, and these polydimethylsiloxane, metal and // A phenyl group is introduced into a part or all of the metalloid alkoxide, maintains a rubber hardness of 70 or less during long-term storage (250 ° C.-1000 hours) at a high temperature, and a high-temperature long-term durability with a weight loss of 6% or less. It is set as the structure with the property.

JP 2004-210857 A JP 2005-281635 A JP 2008-231402 A JP 2009-292970 A International Publication No. 2012/023618

  As described above, among the above-mentioned patent documents, in the organic-inorganic hybrid prepolymer described in Patent Document 5, a phenyl group is added to a part or all of polydimethylsiloxane and metal and / or metalloid alkoxide. Although it has high-temperature long-term durability that allows long-term storage at high temperatures by carrying out dehydration polycondensation reaction while being introduced, in other patent documents 1 to 4, no consideration is given to long-term heat resistance at high temperatures. Absent.

  The present invention has been made from the above-described prior art, and an object thereof is to provide a silicone composition having excellent long-term heat resistance at high temperatures.

In order to achieve this object, the present invention provides a silicon alkoxide-modified polydimethylsiloxane in which a terminal hydroxyl group of polydimethylsiloxane is modified with silicon alkoxide and an alkoxy group stabilized with ethyl acetoacetate having 4 to 8 carbon atoms. and poly ethyl acetoacetate terminal hydroxyl group was modified dimethylsiloxane modified titanium alkoxide-modified polydimethylsiloxane of titanium alkoxide, Tona is, the silicon alkoxide is ethyl silicate molecular weight 750-1000, the silicon alkoxide modified poly The weight ratio of dimethylsiloxane to the ethyl acetoacetate-modified titanium alkoxide-modified polydimethylsiloxane is 1: 1 or more and 1: 4 or less .

The present invention thus constituted includes a silicon alkoxide-modified polydimethylsiloxane in which the terminal hydroxyl group of polydimethylsiloxane is modified with silicon alkoxide, and a titanium alkoxide having 4 to 8 carbon atoms in the alkoxy group stabilized with ethyl acetoacetate. and denatured ethyl acetoacetate modified titanium alkoxide modified polydimethylsiloxane hydroxyl-terminated polydimethylsiloxane with, Tona is, the silicon alkoxide, and ethyl silicate molecular weight 750-1000, and silicon alkoxide-modified polydimethylsiloxane, acetoacetate the weight ratio of ethyl modified titanium alkoxide-modified polydimethylsiloxane, 1: 1 or more 1: 4 or less and be Rukoto be excellent silicone composition in heat resistance at high temperatures.

In particular, when the weight ratio of silicon alkoxide-modified polydimethylsiloxane and ethyl acetoacetate-modified titanium alkoxide-modified polydimethylsiloxane is 1: 1 or more and 1: 4 or less, a silicone composition having excellent long-term heat resistance can be obtained. .

  Further, the present invention is characterized in that, in the above invention, the ethyl acetoacetate-modified titanium alkoxide-modified polydimethylsiloxane is prepared such that the molar ratio of ethyl acetoacetate to the titanium alkoxide is 70 or more.

  In the present invention configured as described above, since the ethyl acetoacetate modified titanium alkoxide modified polydimethylsiloxane is prepared with a molar ratio of ethyl acetoacetate to titanium alkoxide of 70 or more, the silicone composition is more excellent in heat resistance. You can make things.

  In the present invention, the titanium alkoxide is any one of titanium butoxide and titanium tetra-2-ethylhexoxide.

  This invention comprised in this way can be made into the silicone composition excellent in the heat resistance under high temperature by using any one of titanium butoxide and titanium tetra-2-ethylhexoxide as titanium alkoxide.

In the present invention, the silicon alkoxide-modified polydimethylsiloxane obtained by modifying the terminal hydroxyl group of polydimethylsiloxane with silicon alkoxide and the alkoxy group stabilized with ethyl acetoacetate (also referred to as chelate coordination or modification) have 4 or more carbon atoms. 8 was modified terminal hydroxyl groups of the polydimethylsiloxane in the following titanium alkoxide, and ethyl acetoacetate modified titanium alkoxide-modified polydimethylsiloxane, Ri Tona, silicon alkoxide, and ethyl silicate molecular weight 750-1000, silicon alkoxide modified poly and dimethylsiloxane, and the weight ratio of the ethyl acetoacetate-modified titanium alkoxide-modified polydimethylsiloxane, 1: 1 or more 1: by the structure shall be the 4 or less, excellent silicone composition in heat resistance at high temperatures it can Problems, configurations, and effects other than those described above will be clarified from the following description of the embodiments.

It is a chemical formula which shows the raw material liquid A which modified | denatured the both terminal hydroxyl group of PDMS which concerns on the silicone composition of this invention with the alkoxide. It is a chemical formula which shows the raw material liquid B which modified | denatured the terminal of PDMS which concerns on the said silicone composition with titanium alkoxide, and modified with EAcAc. It is a graph which shows the hardness change at the time of 250 degreeC storage of the silicone composition obtained by mixing A0, A12, and A22 liquid with the ratio of 1: 1 molar ratio with respect to the raw material liquid B (T1E70). It is a graph which shows the weight reduction at the time of the 250 degreeC storage of the silicone composition obtained by mixing A0, A12, A22 liquid with the ratio of 1: 1 molar ratio with respect to the raw material liquid B (T1E70). It is a graph which shows the weight change at the time of 250 degreeC long-term storage of the hardening body which consists of the raw material liquid B produced on the conditions from which the reaction ratio of titanium alkoxide TA (titanium tetra-2-ethylhexoxide) and EAcAc differs. It is a graph which shows the weight change after 250 hours 500 degreeC and 900 hours of the hardening body which consists of the raw material liquid B produced on the conditions from which the reaction ratio of titanium alkoxide TA (titanium tetra-2-ethylhexoxide) and EAcAc differs. . It is a graph which shows the hardness after 250 degreeC 1000 hours of the hardening body which consists of the raw material liquid B produced on the conditions from which the reaction ratio of titanium alkoxide TA (titanium tetra-2-ethylhexoxide) and EAcAc differs. It is a graph which shows the hardness change at the time of 250 degreeC storage of the silicone composition obtained by mixing raw material liquid B (T1E70) of a different molar ratio with respect to A12 liquid. It is a graph which shows the weight change at the time of 250 degreeC storage of the silicone composition obtained by mixing raw material liquid B (T1E70) of a different molar ratio with respect to A12 liquid. It is a graph which shows the hardness change at the time of 250 degreeC storage of various titanium alkoxide terminal PDMS (T1EAC70) = 1: 1. It is a graph which shows the weight change of various titanium alkoxide terminal PDMS (T1EAC70) = 1: 1. It is a graph which shows the hardness change at the time of 250 degreeC storage of an AcAc product and an EAcAc product. It is a graph which shows the weight change of an AcAc product and an EAcAc product. It is a graph which shows the hardness change at the time of 250 degreeC storage of the comparative examples 2 and 3. It is a graph which shows the weight change at the time of 250 degreeC storage of the comparative examples 2 and 3. It is a table | surface which shows the low molecular weight generate | occur | produced when heat-processing at 250 degreeC for 1 minute.

  The silicone composition according to the present invention is a so-called organic-inorganic hybrid silicone rubber, for example, a resistor that constitutes a control circuit of a motor that handles high power, such as a hybrid vehicle (HEV) or an electric vehicle (EV). Used in the vessel. That is, this silicone composition is a silicone resin for a protective film that can be used in a high heat-resistant application that can cope with high power, that is, high heat generation.

  In this silicone composition, the terminal hydroxyl group of polydimethylsiloxane (PDMS) is modified with silicon alkoxide and the silicon alkoxide modified polydimethylsiloxane shown in FIG. 1 (raw material liquid A) and the terminal is called ethyl acetoacetate (hereinafter referred to as EAcAc). ) Modified titanium alkoxide (the alkoxy group has 4 or more carbon atoms), and the terminal of polydimethylsiloxane is modified with ethyl acetoacetate modified titanium alkoxide modified polydimethylsiloxane (raw material solution B) shown in FIG. As a skeletal material. And this silicone composition is bridge | crosslinked by heat-curing using these main frame materials. Specifically, a reaction occurs between the hydroxyl group produced by hydrolysis of the silicon alkoxide of the raw material liquid A with moisture in the air and the ethyl acetoacetate-modified titanium alkoxide of the raw material liquid B to form a crosslinked structure. . This crosslinked structure is an organic-inorganic hybrid silicone rubber cured product excellent in heat resistance and flexibility.

  However, titanium alkoxide is generally highly reactive and difficult to handle. Therefore, titanium alkoxide as a functional group that undergoes a cross-linking reaction is reacted with one or both ends of polydimethylsiloxane (PDMS), and the molecular weight of polydimethylsiloxane (PDMS) is adapted to the entire silicone composition. By adjusting the balance of the occupied crosslinking functional groups, a network structure can be formed in this silicone composition, and a silicone composition having both flexibility and heat resistance can be formed. Moreover, by modifying the functional group that undergoes a crosslinking reaction with EAcAc, the thermal stability can be improved while maintaining the reactivity of the pre-reaction composition, and the handleability of the pre-reaction composition can be improved.

  By using titanium alkoxide chelated with EAcAc as a material having a β-diketone structure, elimination of EAcAc coordination hardly occurs at about 250 ° C. For this reason, it is assumed that the final elimination of EAcAc occurs at the same temperature also in polydimethylsiloxane having a titanium alkoxide chelate-coordinated with EAcAc at the terminal. Specifically, in titanium alkoxide-terminated PDMS chelated with EAcAc, it is said that a curing reaction occurs at a temperature of about 250 ° C. or higher, and that chelate desorption occurs in a temperature range of about 250 ° C. to 400 ° C. Yes.

  In silicon alkoxide-terminated PDMS (raw material liquid A), when the terminal is partially modified with EAcAc, the silicon alkoxide whose PDMS terminal β-diketone is not modified is partially exposed to hydrolysis by heating when exposed to the atmosphere. Presumed to be a hydroxyl group. When a silicon alkoxide modified with β-diketone at this end and a PDMS having a hydroxyl group (raw material liquid A) and a titanium alkoxide modified PDMS (raw material liquid B) modified with EAcAc are mixed and subjected to heat treatment at a temperature close to 250 ° C. The active hydroxyl group of the silicon alkoxide-modified PDMS (raw material liquid A) is less stable than the silicon alkoxide modified with β-diketone, which reacts with the titanium alkoxide modified with EAcAc, and the β-diketone is eliminated, A cross-linked structure is formed between the molecules of PDMS of liquid A and PDMS of raw material liquid B, so that the structure can be cured and stable against heat. At this time, EAcAc coordinated to a large number of alkoxides remaining in the cured silicone composition does not desorb up to a temperature close to 400 ° C., and can suppress the polycondensation reaction, thus ensuring stability against heat.

  In the present invention, the silicon alkoxide introduced into the terminal portion of the raw material liquid A is not TEOS but ethyl silicate which is a polycondensate of TEOS. If there are few alkoxy groups from the beginning, the reactive groups required for crosslinking will decrease, and gelation will not proceed. By modifying a part of the silicate having many reactive groups with β-diketone, the number of reactive groups can be controlled and the reactivity can be adjusted.

  In the titanium alkoxide-modified PDMS (raw material solution B) modified with β-diketone, it is basically desirable to chelate all the functional groups of the titanium alkoxide at the terminal portion. Since titanium alkoxide has high reactivity, when there is a functional group that is not chelated, a hydrolysis reaction and a dealcoholization reaction occur at a temperature close to room temperature.

  In the process of synthesizing PDMS having a structure in which titanium alkoxide chelated to all functional groups is introduced into the terminal portion of PDMS, the high reactivity of titanium alkoxide becomes a problem. Titanium alkoxide is introduced into the PDMS end by dealcoholization reaction between the titanium alkoxide and the hydroxyl group at the PDMS end. However, if the titanium alkoxide is not partially subjected to stabilization treatment with a chelate in advance, the alkoxides are copolymerized with each other. It is easy to introduce into the PDMS end. When the three alkoxides of the terminal functional group are chelated, the titanium alkoxy chelate forms an aggregate and the reactivity with PDMS decreases. In the case where one alkoxide is chelated, the reactivity after introduction into PDMS is too high. Therefore, in the present technology, among a plurality of titanium alkoxides, a titanium alkoxy chelate in which two alkoxides are chelated in advance is used.

  In order to mix titanium alkoxide (titanium alkoxy chelate) partially modified (chelated) in advance to suppress the reactivity of titanium alkoxide and PDMS, the viscosity of PDMS is increased by dilution with a solvent to increase the compatibility. It is necessary to lower. Furthermore, since a reactive functional group remains in the titanium alkoxide introduced into the PDMS terminal hydroxyl group, it is necessary to add a β-diketone to completely chelate the PDMS terminal alkoxide. When alcohol or the like is used as a solvent, when titanium alkoxide (titanium alkoxy chelate), PDMS, and β diketone are mixed, immediately after formation of alkoxy chelate-modified PDMS by reaction of PDMS with titanium alkoxy chelate, alkoxy Since a polymerization reaction between chelates occurs and PDMS is polymerized, it is difficult to synthesize PDMS having a structure in which the terminal portion of PDMS is modified with titanium alkoxide coordinated to all functional groups.

  Therefore, in the present technology, β-diketone is used as a solvent component. By using the same β-diketone as the chelating agent and the solvent, it is possible to suppress the reaction as a crosslinking agent of the titanium alkoxy chelate incorporated in PDMS and appropriately adjust the crosslinking reaction with the PDMS molecule. As a result, β diketones are excessive with respect to the number of moles of titanium alkoxide.

  Here, having heat resistance and being “stable to heat” can be considered to have two points that there are few components that escape from the silicone composition and there is little weight loss and that the curing reaction does not proceed due to heat. .

  As a component that escapes from a general silicone composition at a high temperature, generation of cyclic siloxane accompanying thermal decomposition of PDMS can be mentioned. Thermal decomposition in a silicone composition proceeds mainly by a depolymerization (Unzipping) mechanism and a random scission mechanism. According to the depolymerization, the low-molecular cyclic siloxane is desorbed from the terminal part of the uncrosslinked PDMS main chain. Since depolymerization tends to occur when there are terminal groups such as Si-OH or Si-R-OH at the terminal, in order to suppress the depolymerization, the residual PDMS terminal reactive groups in the silicone composition should be reduced. Good. Random decomposition occurs by the occurrence of random rearrangement of siloxane bonds within or between PDMS molecules at high temperatures. In this case, low molecular cyclic siloxane and linear siloxane are produced. By suppressing the degree of freedom of PDMS molecules by forming a cross-linked structure, random polymerization can be suppressed.

  As described above, in order to suppress thermal decomposition, by using a method such as a stabilization treatment by chelation, the residual reactive group at the PDMS terminal is reduced in the silicone composition, and a firm crosslinked structure is formed. It is necessary.

  When unreacted groups remain in the silicone composition, when stored for a long time at room temperature, the unreacted groups react with each other to cause a crosslinking reaction. Further, when stored at a high temperature, the crosslinking reaction due to the reaction between unreacted groups proceeds rapidly, and the hardness of the silicone composition is likely to increase in a short time. In order to suppress these cross-linking reactions, it is first necessary to eliminate the reactive groups remaining in the silicone composition, or to sufficiently separate the remaining reactive groups. In the chelate stabilization treatment, the number of reactive groups of the metal alkoxide at the PDMS end portion can be reduced, and the chelate molecule is bulky, so that it is expected that the interval between reactive groups can be increased.

  When the raw material liquid A is excessive in the silicone composition, excessive silicon alkoxide at the end of the raw material liquid A remains in the silicone composition, and therefore when the silicone composition is exposed to a high temperature (the raw material liquid B is excessive In the same manner as in some cases, in the PDMS terminal portion, a silicon alkoxide unmodified with β-diketone may form a large number of hydroxyl groups by reaction with water in the atmosphere. The hydroxyl group acts as a reactive group, and serves as a starting point for the crosslinking reaction between the alkoxide and hydroxyl group of the raw material liquid A and the EAcAc-modified titanium alkoxide of the raw material liquid B and the thermal decomposition reaction of the raw material liquid A. For this reason, when the raw material liquid A is excessive when forming a silicone composition, it is estimated that the heat resistance of a silicone composition falls. (Supplementary comment: From the results, it is considered that the hardness increase is remarkable and the crosslinking reaction is likely to proceed)

On the other hand, when the raw material liquid B is excessive when forming the silicone composition, a large amount of titanium alkoxide modified with EAcAc remains in the cured product. This EAcAc-modified titanium alkoxide is thermally stable for a short time, but when exposed to a high temperature for a long time, EAcAc is desorbed by reaction with water in the atmosphere at the PDMS terminal portion, There is a possibility of substitution with a hydroxyl group. The hydroxyl group acts as a reactive group, and serves as a starting point for the crosslinking reaction between the alkoxide and hydroxyl group of the raw material liquid A and the EAcAc-modified titanium alkoxide of the raw material liquid B and the thermal decomposition reaction of the raw material liquid B. For this reason, when the raw material liquid B is excessive when forming a silicone composition, it is estimated that the heat resistance of a silicone composition falls. (Supplementary comment: From the results, it is considered that the increase in hardness tends to be gradual and the decrease in weight tends to increase, which facilitates the thermal decomposition reaction.)

  Silicon alkoxide modification partially modified with β diketone by mixing β diketone modified silicon alkoxide modified PDMS (raw material liquid A) and EAcAc modified titanium alkoxide modified PDMS (raw material liquid B) in an appropriate ratio in the silicone composition. An active hydroxyl group generated from an unmodified silicon alkoxide of PDMS (raw material A) reacts with a titanium alkoxide modified with EAcAc that is less stable than a silicon alkoxide modified with a β diketone to form a crosslinked structure. By doing so, it is considered that a more stable structure can be taken against heat.

  From the above, the silicone composition according to the present invention can be used in an environment where it is continuously exposed to a high temperature in order not to lose its flexibility even if it is kept at a high temperature and does not lose flexibility. Furthermore, the silicone composition has an appropriate viscosity and can be used as a base resin for making a paste, and can also be used for screen printing by forming a paste containing a filler as required. Moreover, since this silicone composition has the functional group which carries out a crosslinking reaction modified with β-diketone, it is excellent in storage stability at room temperature and can be improved in handleability. Therefore, this silicone composition is suitable for protecting an object that has high heat resistance, flexibility, and high temperature.

  Furthermore, since this silicone composition has a structure having both an inorganic chain and an organic chain inside, this silicone composition protects parts that generate a large amount of heat and protects parts that generate a large amount of heat. Even if exposed, there is no alteration such as an increase in hardness or carbonization, there is no decrease in weight and adhesion due to volatilization of the components, and even if there is a temperature cycle, peeling from the substrate can be eliminated.

  The titanium alkoxide described above preferably has an alkoxy group having 4 or more carbon atoms. Specifically, the titanium alkoxide includes titanium tetranormal butoxide, titanium tetrakis (1-methylpropoxide), titanium tetrakis (2-methylpropoxide), titanium tetrakis (2,2-dimethylethoxide), titanium tetranormal. Pentoxide, Titanium tetranormal hexoxide, Titanium tetranormal heptoxide, Titanium tetranormal octoxide, Titanium tetrakis (2-ethylhexoxide), Titanium tetranormal stearoxide, Titanium tetrakis (2-ethyl, 3- Hydroxyl hexoxide), titanium bis (acetylacetonato) di (propoxide), titanium bis (8-hydroxyoctoxide) dibutoxide, titanium bis (lactate) di (propoxide), titanium bis (triethanolaminate) ) Di (propoxide), titanium bis (triethanolaminato) di (butoxide), titanium monostearate tri (normal butoxide), titanium tristearate mono (isopropoxide), titanium tris (dodecylbenzenesulfonyl) mono (iso) Propoxide), titanium tris (dioctyl pyrophosphate) mono (isopropoxide), titanium bis (dioctyl phosphite) tetra (isopropoxide), titanium bis (ditridecyl phosphite) tetra (octoxide), titanium di (di-tridecyl) tetra (2,2-diallyloxymethyl-1-butoxide) and the like can be used.

Furthermore, in the above-described titanium alkoxide, preferably, tetra-i-propoxytitanium “Ti (Oi-C ₃ H ₇ ) ₄ ”, tetra-n-propoxytitanium “Ti (O—N—C ₃ H _{7). 4} ”, titanium methyl tripropoxide, tetra-1-methoxy-2-methyl-2-propoxy titanium“ Ti [OC (CH ₃ ) ₂ —CH ₂ OCH ₃ ] ₄ ”, tetra-n-butoxy titanium“ Ti _{(O-n-C 4 H} 9) 4 ', tetra -i- butoxy' _{Ti (O-i-C 4} H 9) 4 ', tetra -sec- butoxytitanium _{"Ti (O-sec-C 4} H ₉ ) ₄ ", titanium tetrahexoxide, titanium tetra-2-ethylhexoxide, titanium tetraoctoxide and the like.

Moreover, if the carbon number of the alkoxy group contained in the titanium alkoxide is too large, the reactivity to the dealcoholization reaction may be insufficient, and if the carbon number of the alkoxy group is too small, the reactivity becomes high and the reaction is controlled. because it may be difficult, as the carbon number of the alkoxy group contained in the titanium alkoxide, 4 to 8, i.e. titanium butoxide Kishido or titanium tetra-2-ethylhexoxide, it is particularly preferred.

  Next, as Example 1 of the present invention, a method for producing a silicone composition using silicon alkoxide-modified PDMS (raw material liquid A) and EAcAc-modified titanium alkoxide terminal-modified PDMS (raw material liquid B) as raw materials will be described.

  First, nitrogen gas manufactured by a nitrogen gas manufacturing apparatus (UNX-200 manufactured by Japan Unix Co., Ltd.) is filled into a glass reaction vessel which is a separable flask having a capacity of 300 ml. Next, a hydroxyl group-modified polydimethylsiloxane (YF3057 produced by Momentive Performance Materials, equivalent to an average molecular weight of 38000, hereinafter referred to as “PDMS”) and ethyl MW of 750 to 1000 as silicon alkoxide were placed in this glass reaction vessel. Silicate (ethyl silicate 40 or ethyl silicate 45 manufactured by Tama Chemical Co., Ltd.) is added in order at a molar ratio of 1: 2.

  Furthermore, stirring was performed with a stirring rod equipped with a propeller in a state where dry nitrogen gas was allowed to flow into the glass reaction vessel, and the mixture was heated to 140 ° C. with a hot plate and stirred for 30 minutes. Thereafter, in order to accelerate the reaction, tetra (2-ethylhexyl) titanate (manufactured by Matsumoto Fine Chemical Co., Ltd.) in an amount equivalent to 0.003 mol with respect to PDMS is dropped into a glass reaction vessel and maintained at a temperature of 140 ° C. And stirred. Furthermore, the reaction solution in this glass reaction container is fractionated, the molecular weight distribution is measured with a gel permeation chromatograph (800 system system manufactured by Tosoh Corporation), and the peak corresponding to ethyl silicate disappears. Stirring was continued. Then, the liquid temperature of this reaction solution was cooled to room temperature to obtain silicon alkoxide-terminated PDMS (raw material liquid A molecular weight 41000).

  First, ethyl acetoacetate is used per 1 mol of titanium tetra-2-ethylhexoxide (hereinafter referred to as “TA” manufactured by Matsumoto Fine Chemical Co., Ltd.) so that the amount corresponding to one end of PDMS is modified with titanium alkoxide. 2 mol equivalent (manufactured by Kanto Chemical Co., Inc.) was sealed in a glass container with a lid in a nitrogen atmosphere, and then stirred at room temperature for 24 hours with a magnetic stirrer to obtain a TA raw material solution coordinated with EAcAc. Subsequently, both ends hydroxyl-modified PDMS (Momentive Performance) is placed in a glass reaction vessel which is a separable flask having a capacity of 300 ml and filled with nitrogen gas produced by a nitrogen gas production apparatus (UNX-200 manufactured by Japan Unix Co., Ltd.). YF3057 (equivalent to an average molecular weight of 38000) manufactured by Materials Co., Ltd., TA raw material coordinated with EAcAc, and excess ethyl acetoacetate EAcAc were added at a molar ratio of 1: 1: 70.

  Thereafter, while stirring the solution in the glass reaction vessel with a stirring rod equipped with a propeller, the reaction solution was heated to 80 ° C. with a hot plate, stirred for 30 minutes, and then reacted in the glass reaction vessel. The solution was heated to 180 ° C. and allowed to react with stirring at 180 ° C. for 1 hour, whereby the TA partially coordinated with EAcAc was deethanolated between the alkoxy group of the uncoordinated portion and the hydroxyl group of the PDMS terminal. A reaction occurs to polymerize. Simultaneously with this polymerization reaction, chelate coordination with excess ethyl acetoacetate is performed on the uncoordinated portion remaining in TA. Thereafter, the reaction solution was temporarily cooled to room temperature, transferred to a 100 cc Teflon (registered trademark) petri dish, heat-treated at 200 ° C. for 4 hours, and then heat-treated at 250 ° C. for 2 hours. Unreacted ethyl acetoacetate not bound to the modified PDMS was removed to obtain EAcAc-modified titanium alkoxide-modified PDMS (raw material liquid B, molecular weight 40000 equivalent). Hereinafter, the raw material liquid B synthesized at a molar ratio of PDMS: TA: EAcAc = 1: 1: 70 is referred to as “T1E70”.

  First, 12 mol amount of EAcAc was added to 1 mol amount of the raw material liquid A, and mixed for 5 minutes with a conditioning mixer (product name: Fotaro Kentaro AR100, manufactured by Shinky Corporation) to obtain a raw material liquid A12. Hereinafter, a raw material liquid in which n mol of EAcAc is mixed with 1 mol of silicon alkoxide-modified PDMS (raw material liquid A) is referred to as “An”. Thereafter, 1 mol of the raw material liquid A1 and 1 to 10 mol of the raw material liquid B are put in an ointment container having a capacity of 30 ml and mixed for 10 minutes with a conditioning mixer to obtain a composition raw material liquid. A sample for property evaluation was prepared.

  Each sample for heat resistance evaluation is heated for 2 hours in a state where the raw material liquid is put in an aluminum cup so that the thickness after curing is 100 μm and the temperature is slowly raised from room temperature to 250 ° C. Processed. As a result, the obtained silicone composition did not change in shrinkage by heat treatment at 250 ° C., and peeling did not occur.

  Here, the measurement of the weight reduction rate when the obtained silicone composition is stored at 250 ° C. will be described. In this measurement, a sample for heat resistance evaluation was stored in a convection-type high-temperature bath at 250 ° C. and measured with an electronic balance (TX223L manufactured by Shimadzu Corporation) at regular intervals up to 500 hours. The weight reduction rate [weight reduction rate = (sample initial weight−sample weight) / sample initial weight × 100] was measured.

  Here, the measurement of the change in hardness when the obtained silicone composition is stored at 250 ° C. will be described. In this measurement, a sample for heat resistance evaluation is stored in a convection type high-temperature bath in an environment of 250 ° C., and the hardness is measured at regular intervals of up to 500 hours according to JIS K 7312 and SRIS0101 standards (polymer ASKER C-type rubber / plastic hardness meter manufactured by Keiki Co., Ltd., hereinafter referred to as “Asker”).

Table 1 shows the presence / absence of cracks / peeling during storage at 250 ° C., hardness and weight reduction ratio after storage for 500 hours for each heat resistance evaluation sample. In Table 1, the measurement results of the sample using only the raw material liquid A (A12) as a raw material and the sample using only the raw material liquid B (T1E70) as a raw material are also shown as comparative examples.

  As a result, the hydroxyl group-terminated PDMS (oil) was cured after several hours when stored at 250 ° C., and then cracked within 24 hours. Vitrification was progressing when the hardness of the oil before cracking was 80 or more. In addition, even after cracking, storage at 250 ° C. was continued, and the weight after 500 hours was confirmed. As a result, the weight decreased by 45% and the weight decrease was very large. And the reason for this weight reduction is considered to be due to volatilization in the production of cyclic siloxane.

  On the other hand, when only silicon alkoxide-modified PDMS (raw material liquid A) was used as the raw material, the hardness was lower than that of the hydroxyl-terminated PDMS, and the weight loss rate after storage at 250 ° C. for 500 hours was only 10.5%. However, cracks occurred after 48 hours, and the long-term heat resistance was not sufficient.

  Furthermore, when EAcAc-modified titanium alkoxide-modified PDMS (raw material liquid B) is used as a raw material, cracking does not occur even after 1000 hours, and the hardness after 16 hours is as low as 16, but the weight reduction rate is 16%. In this respect, long-term heat resistance is not sufficient.

  In contrast, when silicon alkoxide-modified PDMS (raw material liquid A) and EAcAc-modified titanium alkoxide-modified PDMS (raw material liquid B) are used as raw materials, cracks do not occur even after 1000 hours at 250 ° C., and about 60 The silicone composition maintained a low hardness and had a very high heat resistance with a weight loss rate of 2.7%.

  In the silicone composition using silicon alkoxide-modified PDMS (raw material liquid A) and EAcAc-modified titanium alkoxide-modified PDMS (raw material liquid B) shown in Example 1 as a raw material, EAcAc was added to raw material liquid A. Although shown about the case, even if it changes the addition amount of EAcAc, it will become a material which has the outstanding long-term heat resistance with respect to the existing material.

  The long-term heat resistance of the silicone composition according to the present invention produced using the amount of EAcAc added to the raw material liquid A as a parameter will be described.

  First, using the same production method as in Example 1, a silicone composition composed of the raw material liquid An and the raw material liquid B using the added amount of EAcAc as a parameter is prepared. Here, as the raw material liquid A, a raw material liquid obtained by adding 0, 12, 22 mol of EAcAc to 1 mol of the raw material liquid A (hereinafter referred to as raw material liquids A0, A12, A22) was used. As in Example 1, T1E70 (a material synthesized at a molar ratio of PDMS: TA: EAcAc = 1: 1: 70) was used as the raw material liquid B. A silicone composition prepared by mixing the raw material liquid An (n = 0, 12, 22) and the raw material liquid B in x: y is An (n = 0, 12, 22): B = x: y curing. Indicated as body.

  Here, the weight loss and the change in hardness of the silicone composition obtained by mixing A0, A12, and A22 liquids at a molar ratio of 1: 1 to the raw material liquid B (T1E70) during storage at 250 ° C. are shown. 3 and FIG. In FIG. 3, the relationship between the elapsed time after putting each test piece into the thermostat kept at 250 ° C. and the hardness is shown (vertical axis: hardness, horizontal axis: storage time [Hours]). Moreover, in FIG. 4, each test piece shows the relationship between the elapsed time after putting in the thermostat kept at 250 degreeC, and the weight reduction rate (vertical axis: weight reduction rate [%], horizontal axis: Storage time [Hours]).

  As described above, when the addition amount of EAcAc was changed, in any case, the weight reduction rate was 8% or less, and good results could be obtained, and the case where 12 mol of EAcAc was added was an appropriate amount. In addition, although the change in hardness during storage at 250 ° C. due to the difference in the amount of EAcAc added to the raw material liquid A is slight, it can be seen that by adding an appropriate amount of EAcAc, the lowest hardness can be maintained and low hardness can be maintained. It was. Furthermore, the improvement in heat resistance by adding an appropriate amount of EAcAc is achieved by reducing the number of reactive groups in the raw material liquid A, thereby suppressing the reactivity of the raw material liquid A and suppressing the aggregation of the raw material liquid A components. It is presumed to be based on a uniform dispersion structure with the raw material liquid B. That is, it is considered that even if the amount of EAcAc added is excessively increased, the reaction balance between the raw material liquid A and the raw material liquid B is lost, and the effect of obtaining a uniform silicone composition is reduced.

  A raw material solution B prepared under different reaction ratios of titanium alkoxide TA (titanium tetra-2-ethylhexoxide) and EAcAc was prepared and cured under the conditions of Example 1 to obtain a cured product. When these cured bodies were stored at 250 ° C. for a long time and the change in weight was measured, the change in weight decreased as the EAcAc / TA ratio increased. The weight change in that case is shown in FIG.

  Furthermore, in the raw material liquid B produced on the conditions from which the reaction ratio of EAcAc / TA differs, the reaction ratio of EAcAc / TA and the weight reduction after 500 hours and 900 hours are plotted, and it was shown in FIG. In FIG. 6, it can be seen from the slope of the plot that the degree of change in weight changes around a molar ratio of 70.

  Furthermore, FIG. 7 shows the hardness after 250 hours at 250 ° C. of a cured body made of the raw material liquid B prepared under different conditions of the reaction ratio of TA and EAcAc. A cured product produced from a raw material solution produced under a molar ratio of 8 or less was cracked and destroyed within 250 hours at 600C. A cured product produced from a raw material liquid having a molar ratio of 35 or more did not break even after 1000 hours. Also for the hardness plot, the change in slope appears to be near a molar ratio of 70. From these things, when EAcAc / TA = 70 or more, it can be said that the heat resistance improvement effect of a hardening body has appeared.

  Next, the long-term heat resistance of a silicone composition produced by the same production method as in Example 1 above using the mixing ratio of the raw material liquid A and the raw material liquid B as parameters will be described. In this case, as the raw material liquid A, a raw material liquid (A12 liquid) obtained by adding 12 mol of EAcAc to 1 mol of the raw material liquid A was used. As in Example 1, T1E70 (a material synthesized at a molar ratio of PDMS: TA: EAcAc = 1: 1: 70) was used as the raw material liquid B. A silicone composition prepared by mixing the A12 liquid and the raw material liquid B at a ratio of x: y is expressed as A12: T1E70 = x: y.

  Here, FIG. 8 and FIG. 9 show the change in hardness and the change in hardness and weight during storage at 250 ° C. of the silicone composition obtained by mixing the raw material liquid B (T1E70) having a different molar ratio with respect to the A12 liquid. . In these FIG. 8 and FIG. 9, each test piece has shown the relationship between the elapsed time after putting into the thermostat kept at 250 degreeC, and the weight reduction rate (vertical axis: weight reduction rate [%], Horizontal axis: Storage time [Hours]).

  As described above, none of the sample pieces was cracked or peeled when stored at 250 ° C. for 1000 hours. Further, as the ratio of the raw material liquid A to the raw material liquid B was increased, the hardness increased and the weight loss during storage at 250 ° C. decreased. In particular, in the silicone composition of A12: T1E70 = 1: 3 or 1: 1, the weight loss after storage at 250 ° C. for 1000 hours is less than 5%, and the hardness is less than 60 and the heat resistance is high. A silicone composition could be obtained. On the other hand, for example, when A12: T1E70 = 2: 1, 3: 1, that is, when A12 / T1E70 was set to 1 or more, cracks occurred when stored at 250 ° C. for 100 hours. Therefore, from these results, in terms of long-term heat resistance, it is considered that the range of the mixing ratio of the raw material liquid A and the raw material liquid B is preferably about A12: T1E70 = 1: 1 to 1: 4.

  As the molar ratio of the raw material liquid B to the raw material liquid A is increased, the hardness decreases and the weight loss during storage at 250 ° C. increases. FIG. 8 and FIG. 9 show the hardness and weight reduction rate after 500 hours of storage at 250 ° C. due to the difference in the molar ratio of the raw material liquid A to the raw material liquid A. At the time after storage at 250 ° C. for 1000 hours, the range of the mixing ratio for the weight loss to remain at 7% or less without cracking the cured body and peeling from the container is the mixing ratio of the raw material liquid A and the raw material liquid B. The range of A12: T1E70 = 1: 1 to 1:10. A decrease in hardness and an increase in weight reduction are in a trade-off relationship, and it is considered that A12: T1E70 = 1: 1 to 1: 4 is more desirable for low hardness and small weight change. In this case, the range of the mixing ratio of the raw material liquid A and the raw material liquid B for the weight reduction to remain at 5% or less is about A12: T1E70 = 1: 1 to 1: 3.

  In addition, since the molecular weights of silicon alkoxide, titanium alkoxide, and EAcAc that modify the terminal portion with respect to the molecular weight of polydimethylsiloxane are sufficiently small, the weight ratio and molar ratio of raw material liquid A and raw material liquid B are not greatly different.

  Next, as the titanium alkoxide used for the synthesis of the raw material liquid B, the long-term thermal stability of the silicone composition using titanium tetraisopropoxide and titanium tetra-n-butoxide is changed to titanium tetra-2-ethylhexoxide. Compare with the silicone composition used.

  First, as the silicon alkoxide-modified PDMS (raw material liquid A), one produced by the same method as in Example 1 was used.

  Subsequently, EAcAc-modified titanium alkoxide-modified PDMS (raw material liquid B) is ethyl acetoacetate per 1 mol of titanium tetra-n-butoxide (manufactured by Kanto Chemical Co., Inc.) or titanium tetraisopropoxide (manufactured by Kanto Chemical Co., Ltd.). 2 mol equivalent of (EAcAc) was sealed in a glass container with a lid in a nitrogen atmosphere, and then stirred for 24 hours at room temperature with a magnetic stirrer to obtain a raw material solution coordinated with EAcAc. Furthermore, the nitrogen gas manufactured with the nitrogen gas manufacturing apparatus (Japan Unix Co., Ltd. UNX-200) was filled in the glass reaction container which is a separable flask with a capacity of 300 ml. And, in a glass reaction vessel filled with this nitrogen gas, both-end hydroxyl group-modified PDMS (YF3057 average molecular weight equivalent to 38,000 by Momentive Performance Materials), titanium alkoxide-modified PDMS coordinated with EAcAc, Ethyl acetoacetate EAcAc was added at a molar ratio of 1: 1: 70.

  Further, the solution in the glass reaction vessel was heated to 80 ° C. with a hot plate while stirring with a stirring rod with a propeller, stirred for 30 minutes, and then the solution in the glass reaction vessel was heated to 180 ° C. The reaction was carried out under heating and stirring for 1 hour. The reaction solution in the glass reaction vessel was once cooled to room temperature, then transferred to a 100 cc Teflon petri dish, subjected to heat treatment at 200 ° C. for 4 hours, and then heat treatment at 250 ° C. for 2 hours. It was.

  First, 12 mol amount of EAcAc was added to 1 mol amount of the raw material liquid A, and mixed for 5 minutes with a conditioning mixer (product name: Awatake Kentaro AR100, manufactured by Shinky Co., Ltd.) to obtain a raw material liquid A ′. . Subsequently, 1 mol amount of the raw material liquid A 'and 1 to 10 mol amount of the raw material liquid B were put into an ointment container having a capacity of 30 ml and mixed for 10 minutes with a conditioning mixer to obtain a raw material liquid. And the sample for heat resistance evaluation was produced from these raw material liquids. Here, these heat resistance evaluation samples were prepared in a state where each raw material liquid was placed in an aluminum cup so that the thickness after curing was 100 μm, and the temperature was raised from room temperature to 250 ° C. over 4 hours. Heat treatment was performed over time.

  Here, changes in hardness, hardness and weight of a silicone composition obtained by mixing raw material liquid B (titanium alkoxide-modified PDMS) using different types of titanium alkoxide as a raw material with respect to A12 liquid during storage at 250 ° C. As shown in FIGS. As shown in FIG. 10 and FIG. 11, the titanium tetraisopropoxide sample cracked at 250 ° C. for 200 hours, which is considered inappropriate. On the other hand, it was found that the titanium tetra-n-butoxide product maintained a low hardness at the time of 250 ° C. for 500 hours, and the weight reduction was similar to that of the titanium tetra-2-ethylhexoxide product.

Next, a comparative example of the present invention will be described.
<Comparative Example 1>
When acetylacetone (AcAc) is used as the β-diketone material for stabilizing the alkoxide, the titanium tetra-2-ethylhexoxide: AcAc = 1 to 20 (molar ratio). In this case, when the raw material liquid B is produced, since the polymerization is progressed too much at the time when the heat treatment is performed up to 250 ° C., the viscosity of the raw material liquid B is high and mixing with the raw material liquid A becomes impossible. It was. When titanium tetra-2-ethylhexoxide: AcAc = 70 (molar ratio), the viscosity of the raw material liquid B is lower than that of the titanium tetra-2-ethylhexoxide: AcAc = 1-20 products, and the raw material liquid It became possible to produce a mixture of A and raw material liquid B. However, when mixed at a ratio of raw material liquid A12: raw material liquid B (AcAc coordination product) = 1: 1, as shown in FIG. 12 and FIG. Seems to be unsuitable because bubbles remained and a uniform cured body could not be produced. The AcAc coordination is considered to be because the desorption occurs at a lower temperature than the EAcAc coordination, and thus the curing proceeds in a shorter time than the EAcAc-treated product.

<Comparative example 2>
Next, as Comparative Example 2, a case of the PDMS hybrid shown in the above cited reference 3 (Japanese Patent Laid-Open No. 2008-231402) will be described.

  First, 0.2 mass% of tetraisopropoxy titanium (TIPT) (manufactured by Kanto Chemical Co., Ltd.) is added to 8.2 mass% of t-butanol (manufactured by Wako Pure Chemical Industries, Ltd.), and then tetraethoxysilane ( TEOS) (manufactured by Kanto Chemical Co., Inc.) was added, and then stirred. The solution after stirring was put into 81.4% by mass of polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905 GE Toshiba Silicone Co., Ltd.). The mixture was stirred for 30 minutes to obtain a raw material liquid (curable resin composition). Then, this raw material liquid is poured into a fluororesin petri dish, cured at 100 ° C. for 1 hour in a batch type oven, and then baked at 120 ° C. for 3 hours (dehydration condensation process). A cured product was obtained.

<Comparative Example 3>
As Comparative Example 3, adjustment of the raw material liquid in the case of the PDMS hybrid shown in the above cited reference 3 (Japanese Patent Laid-Open No. 2008-231402) will be described.

  First, raw material liquid A is tetraethoxysilane (TEOS) (manufactured by Kanto Chemical Co., Inc.) 20.5% by mass and polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905 GE manufactured by Toshiba Silicone Co., Ltd.) 76.9% by mass, 2.5% by mass of t-butanol (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.1% by mass of water were mixed, and this mixed solution was stirred at room temperature for 30 minutes to prepare a raw material solution. A.

  Next, the raw material liquid B is 0.5% by mass of tetraisopropoxy titanium (TIPT) (manufactured by Kanto Chemical Co., Ltd.) and polydimethylsiloxane (PDMS) (weight average molecular weight: 20000, trade name: XF3905 GE manufactured by Toshiba Silicone Co., Ltd. ) 86% by mass and t-butanol (manufactured by Wako Pure Chemical Industries, Ltd.) 13.5% by mass were mixed, and this mixed solution was stirred at room temperature for 30 minutes to obtain a raw material solution B.

  Then, the raw material liquid A and the raw material liquid B were mixed at a mass ratio of 1/1, and the mixed liquid was stirred at room temperature for 30 minutes (hydrolysis step) to obtain a colorless and transparent liquid. . Further, this liquid is poured into a petri dish made of fluororesin, cured at 100 ° C. for 1 hour, and then baked at 120 ° C. for 3 hours (dehydration condensation process) to obtain a colorless and transparent silicone composition (organic / inorganic hybrid composition). Got.

  As described above, regarding the change in hardness during storage at 250 ° C. in Comparative Example 2 and Comparative Example 3, as shown in FIG. 14, peeling or cracking occurs within 200 hours. Further, in Comparative Examples 2 and 3, as shown in FIG. 15, when stored at 250 ° C., the weight change at the time when 200 hours passed becomes 8% or more, and as the storage time becomes longer. , Found that the weight continues to change.

  Here, the components of decomposition / volatiles (mainly cyclic siloxane which is a volatile component of low-molecular-weight siloxane) and the amount of volatilization generated from each silicone composition at high temperature are evaluated by the headspace gas chromatography (GC) method. went. In this evaluation measurement, a measurement system including a gas chromatograph (HP6890GC manufactured by Hewlett Packard) and a mass selection detector (HP5973MSD manufactured by Hewlett Packard) was used. The headspace method was used for decomposition and sampling of volatiles.

  Further, for each silicone composition, a 0.5 mm-thick 1.0 g sheet-shaped sample was finely cut and then sealed in a 10-ml vial, and a silicone septum (part number: 5190-3987, manufactured by Agilent Technologies). And sealed with an aluminum cap. After this sealing, the vial is kept at 250 ° C. for 1 minute, and 1 ml of the volatile component purged into the gas phase (head space) is sucked with a gas tight syringe (Agilent Technology part number: 5182-9710). Separation and detection were carried out in the state of being injected into the GC.

  The GC-MS measurement conditions were as follows: inlet temperature: 250 ° C., column: Agilent 19091S-433 (column length 30 m, column inner diameter 0.25 mm, column film thickness 250 μm), oven: 40 ° C. to 15 ° C./min to 300 ° C. (Hold time 2 minutes), helium flow rate: 1.0 mL / min, MS ion source temperature: 230 ° C., MS quadrupole temperature: 150 ° C., MS ionization voltage: 69.9 eV, scan range: m / z 100-800 did. And the volatile component was identified from the MS spectrum obtained by this measurement using analysis software (MSD Chem Station made by Agilent).

  Here, as a comparative example, the results of low molecular weight generated when heat-treated at 250 ° C. for 1 minute are as follows: silicone rubber (SR-50 manufactured by Tigers Polymer Co., Ltd.), hydroxy-terminated PDMS oil (Momentive Performance Materials, Inc.) YF3057) is further added, and the measurement results of Comparative Example 2 are shown. In addition, about the hybrid composition which does not contain the low molecular siloxane shown by the said patent document 4, it produced as Comparative Example 4 and evaluated.

<Comparative example 4>
Next, as Comparative Example 4, the hybrid composition shown in the above cited reference 4 (Japanese Patent Laid-Open No. 2009-292970) will be described.

  First, 1.0 g of ethyl silicate (silicate 40 n = 4 to 6, or silicate 45 n = 6 to 8 manufactured by Tama Chemical Industry Co., Ltd.) is placed in a reaction vessel equipped with a stirrer, a thermometer and a dropping line. 32.0 g of polydimethylsiloxane obtained by alkoxy modification of ethyl silicate at both ends (mass average molecular weight: equivalent to 32000, HBSIL039 manufactured by Arakawa Chemical Co., Ltd.) is stirred and mixed in the atmosphere (room temperature) for about 30 minutes to be a hybrid. It was set as the raw material liquid A. Here, ethyl silicate and silicate used in polydimethylsiloxane obtained by alkoxy-modifying ethyl silicate at both ends were made to have the same kind and characteristics.

  The raw material liquid A was stirred and mixed in the hydrolysis step and the condensation step while adding 0.93 g of a required amount of water dropwise over about 1 hour. Thereafter, the mixture was naturally cooled to room temperature over about 30 minutes with stirring to obtain a hybrid composition. Furthermore, this hybrid composition was poured into a Teflon petri dish (diameter: 103 mm) to a final thickness of 1 mm, dried and baked at 200 ° C. for 2 hours, then demolded from the Teflon petri dish and measured. A test piece sheet (diameter: 103 mm, thickness: 1 mm) was used.

Here, the low molecular component produced | generated when it heat-processes at 250 degreeC for 1 minute about the silicone composition which concerns on this invention, and each comparative example was compared with FIG. In FIG. 16, the volatilization amount of the low molecular component is represented by the area of the detection peak of the chromatogram detected by GC-MS, and the unit is Counts. “0.00E + 00” means 0.00 × 10 ⁰ , that is, 0, and “3.50E + 08” means 3.50 × 10 ⁸ .

  Moreover, the vertical item of FIG. 16 shows the valence of cyclic siloxane or linear siloxane. Therefore, linear siloxane having a valence of 5 to 7 is detected from the silicone composition according to the present invention. On the other hand, the hybrid composition of Comparative Example 3 or Comparative Example 4 generates more low-molecular components than the silicone composition according to the present invention, and has a valence of 5 to 7 in addition to the linear siloxane. 3-14 cyclic siloxanes have been detected. From the above, in the silicone composition according to the present invention, since the generation of cyclic siloxane is limited to pentavalent to heptavalent cyclic siloxane, the generation amount is also greatly reduced compared to the comparative example. I understand.

Claims (3)

Silicon alkoxide modified polydimethylsiloxane in which the terminal hydroxyl group of polydimethylsiloxane is modified with silicon alkoxide,
And polydimethyl acetoacetic modified titanium alkoxide-modified polydimethylsiloxane with terminal hydroxyl groups have been modified siloxane in aceto carbon number of stabilizing processing with alkoxy groups of 4 to 8 of the titanium alkoxide with ethyl acetate, Ri Tona,
The silicon alkoxide is ethyl silicate having a molecular weight of 750 to 1000,
A silicone composition , wherein a weight ratio of the silicon alkoxide-modified polydimethylsiloxane and the ethyl acetoacetate-modified titanium alkoxide-modified polydimethylsiloxane is 1: 1 or more and 1: 4 or less . The silicone composition of claim 1, wherein
The silicone composition characterized in that the ethyl acetoacetate modified titanium alkoxide modified polydimethylsiloxane is prepared with a molar ratio of ethyl acetoacetate to titanium alkoxide of 70 or more . The silicone composition according to claim 1 or 2,
The silicone composition according to claim 1, wherein the titanium alkoxide is any one of titanium butoxide and titanium tetra-2-ethylhexoxide .