JPH08157605A - Silanol-ended silsesquioxane ladder and its production - Google Patents

Abstract

PURPOSE: To efficiently produce an oligomer whose total terminal groups are silanol, capable of curing without any catalyst and providing a cured product having heat resistance and high modulus by subjecting plural organotrihalosilane compounds to cohydrolysis and condensation in a specific solvent. CONSTITUTION: This silanol-ended silsesquioxane ladder oligomer has 500 2000 number-average molecular weight and is expressed by the formula [R<1> is a monovalent hydrocarbon, preferably a 1-3C monovalent hydrocarbon such as methyl; R<2> is an aromatic hydrocarbon, preferably phenyl; number of R<1> is 20-90% based on total number of R<1> and R<2> ; (l), (m), (n) are each >=0; 2<=l+m+n<=15]. The oligomer is obtained by adding an organotrihalosilane mixture expressed by the formula R<1> SiX3 or R<2> SiX3 (X is a halogen) to two phase system consisting of an organic solvent and water in the presence of an alkali metal carboxylic acid and an aprotic polar organic solvent and subjecting the mixture to cohydrolysis and condensation. The resultant oligomer has plural kinds of organic substituent groups on silicon. Specifically, the oligomer is obtained by dropping an organotrihalosilane to two phases of benzene, etc., and water under stirring of a mixture of sodium acetate with acetone to react the silane compounds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to silanol-terminated silsesquioxane ladder oligomers and a method for producing the same. The present invention relates to an oligomer and a method for producing the oligomer.

[0002]

2. Description of the Related Art Ladder type polysiloxane is known as a material which is excellent in heat resistance and electric insulation and can be used as a coating material, a coating agent, a sealing material for electronic devices and the like. Known silanol-terminated silsesquioxanes include polyphenylsilsesquioxane and polymethylsilsesquioxane. Also known are silsesquioxanes having a plurality of substituents on silicon such as a methyl group, a phenyl group and a vinyl group. However, silanol-terminated polyphenylsilsesquioxane is obtained as an oligomer having a molecular weight of several hundreds to several thousands when PhSiCl ₃ is hydrolyzed. It is fragile and cannot be used. When the substituent on the silicon is an aliphatic hydrocarbon group such as methyl or vinyl, the reactivity of the RSiX ₃ type monomer giving the silanol end is high, and the molecular weight of the resulting hydrolysis-condensate is almost 1 It will be over 10,000. Therefore, it has poor solubility in a solvent, a large amount of solvent is required to dissolve the condensate, and a thin film for coating applications or the like can be obtained, but a cured product having a certain thickness can be obtained because of cracks or the like. I couldn't do that. A low-molecular-weight silsesquioxane oligomer having a plurality of substituents on silicon is also known, but this has an alkoxysilyl group at the molecular end, and the reaction at the time of curing is slow. There was a problem that the physical properties were not sufficient depending on the purpose of use, for example, the elastic modulus of the cured product was not so high.

Ladder type polysiloxanes are generally synthesized by subjecting an organotrialkoxysilane or an organotrihalosilane to a hydrolysis / condensation reaction. When an organotrialkoxysilane is used, the silsesquioxane ladder polysiloxane that is generally formed has an alkoxysilyl group at the terminal, and there is a problem that the reactivity during curing is insufficient depending on the purpose of use. on the other hand,
In addition to phenyltrichlorosilane, when alkyltrichlorosilane is used in combination or alone, the reactivity is high, and there is a problem that gelation tends to occur in the usual method of adding water to organotrihalosilane or dropping trihalosilane to water. It was

Therefore, in order to suppress gelation, an alkali metal carboxylate and a lower alcohol are dissolved in a two-phase system of water and an organic solvent, and organotrichlorosilane is added dropwise to the ladder while stirring so as not to disturb the two-phase interface. A method of synthesizing type polysiloxane has been proposed (Japanese Patent Laid-Open No. 3-227321). As a result of investigations by the present inventors, a ladder-type polysiloxane having a narrow molecular weight distribution was obtained by this method, but 2 out of 4 terminal functional groups in one molecule were obtained.
It was found that one or more of them are converted into alkoxy groups due to the alcohols present in the synthesis system, and it is not possible to synthesize a ladder-type polysiloxane having silanol groups at all molecular terminals.

[0005]

The object of the present invention is to prepare a plurality of organotrihalosilanes as raw materials, and co-hydrolyze and condense them in a specific mixed solvent to prevent gelation during production. (EN) It is intended to provide a low-molecular-weight silsesquioxane ladder oligomer having a plurality of kinds of organic substituents on silicon and all four molecular terminal functional groups being silanol efficiently, and a method for producing the same.

[0006]

Means for Solving the Problems The object of the present invention have the general formula (1) (R ¹ is a monovalent hydrocarbon group, R ² is an aromatic hydrocarbon group, the number of R ¹ is R ¹ and a 20% to 90% of the total number of R ^2, l, m, n is 0 or a positive number, the average of these sums represented by a 2 ≦ l + m + n ≦ 15.), a number average molecular weight 500 ~ 2000 silanol terminated silsesquioxane ladder oligomers,

[0007]

Embedded image

Further, an alkali metal carboxylic acid and an aprotic polar organic solvent are dissolved in a two-phase system consisting of an organic solvent phase and an aqueous phase, and formula (2): R ¹ SiX ₃ and formula (3): R ² SiX are dissolved. ₃ (R ¹ is a monovalent hydrocarbon group, R ² is an aromatic hydrocarbon group, and X is a halogen atom), and a mixture of organotrihalosilane is added dropwise to co-hydrolyze and condense the mixture. The method for producing a silanol-terminated silsesquioxane ladder oligomer according to claim 1, wherein the silanol-terminated silsesquioxane ladder oligomer is produced.

The silanol-terminated silsesquioxane ladder oligomer represented by the formula (1) of the present invention is characterized in that plural kinds of organic substituents are awaited on silicon, and all of the molecular terminals are silanol groups. R ¹ is a monovalent hydrocarbon group, R ² is an aromatic hydrocarbon group, and R ¹ is 20 to 9 in total.
0%, l, m, and n are 0 or positive numbers, and the average of the sum thereof is 2 ≦ l + m + n ≦ 15.

In the formula (1), R ¹ and R ² in n repeating units (hereinafter, this unit is referred to as n unit)
May be the same or different for every n units. This means m repeating units (hereinafter this unit is called m unit).
The same is true for R ^1, l number of repeating units (hereinafter, the units of l unit) The same applies to R ² in. Further, the n unit, the m unit, and the l unit may be blocks or may be a random mixture of these.

R ¹ is a monovalent hydrocarbon group, preferably a monovalent hydrocarbon group having 1 to 3 carbon atoms. Examples of such a hydrocarbon group include a methyl group, an ethyl group and n-propyl group. Group, iso-propyl group, vinyl group, allyl group, chloromethyl group, trichloroethyl group, chloropropyl group and the like. R ² is, for example, a phenyl group,
Examples thereof include a tolyl group, a xylyl group and a chlorophenyl group, and R ¹ is 20 to 90% of the whole, preferably 30 to 80.
%. Further, l, m and n are 0 or a positive number, and the average of the sum thereof is 2 ≦ l + m + n ≦ 15, preferably 3 ≦ l
+ M + n ≦ 10.

The silanol-terminated silsesquioxane ladder oligomer (hereinafter, also referred to as ladder-type polysiloxane) of the present invention has a number average molecular weight of 500 to 100 in terms of standard polystyrene by gel permeation chromatography.
2000, preferably 700-1500. The starting material organotrihalosilane in the method for producing a ladder-type polysiloxane according to the present invention is represented by the formula (2): R ¹ SiX ₃
And formula (3): R ² SiX ₃ . Where R
¹ and R ² have the same meaning as in formula (1). X is a halogen atom and is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, preferably a chlorine atom or a bromine atom, and most preferably a chlorine atom.

To obtain the compound of formula (1), at least one compound of formula (2) and at least one compound of formula (3) are used in the reaction, preferably one each, most preferably Is a combination of methyltrichlorosilane and phenyltrichlorosilane. The amount of water used in the production method of the present invention is at least 1.5 mol per 1 mol of organotrichlorosilane, but when X is a chlorine atom, it is generally 100 to 500 parts by weight per 100 parts by weight of organotrichlorosilane. Parts, preferably 200-40
0 parts by weight.

The organic solvent used in the present invention may be dissolved in water to some extent, but it can form an organic solvent phase in water. Specifically, benzene, toluene, xylene, chlorobenzene, chlorotoluene, methyl ethyl ketone, diethyl ketone, diethyl ether,
Dibutyl ether and the like can be mentioned. The amount of the organic solvent used in the present invention is 100 to 500 parts by weight, preferably 200 to 4 parts by weight, based on 100 parts by weight of trihalosilane.
It is 00 parts by weight. When the amount of the organic solvent used is less than 100 parts by weight, it is insufficient to dissolve the generated ladder-type polysiloxane, and the generated ladder-type polysiloxane has a high molecular weight. Further, if it exceeds 500 parts by weight, hydrolysis of trihalosilane does not sufficiently occur and it is uneconomical.

Further, in the production method of the present invention, the aprotic polar organic solvent present in the reaction system is a mixture with water at substantially any ratio, and acts as a cosolvent of water and the organic solvent. , Trihalosilane is used to gently contact water so that it can be gradually hydrolyzed. Specifically, acetone, tetrahydrofuran, 1,
4-dioxane, 1,2-dimethoxyethane and the like can be mentioned, but acetone is preferably used. Alcohols cannot be used because the silanol at the terminal of the generated ladder-type polysiloxane is alkoxylated. The amount of the organic solvent used in the present invention is in the range of 1 to 100 parts by weight, preferably 5 to 5 parts by weight based on 100 parts by weight of water.
0 parts by weight. This is because if the amount is less than 1 part by weight, the generated ladder-type polysiloxane will gel. On the other hand, if the amount exceeds 100 parts by weight, separation of the organic phase and the aqueous phase becomes poor at the time of washing with water after the reaction, and purification becomes difficult.

The alkali metal carboxylate used in the present invention functions to capture hydrogen halide produced by hydrolysis of organotrihalosilane. In addition, the carboxylic acid by-produced by this reaction forms a buffer together with the alkali metal carboxylate, and acts to prevent the generated ladder-type polysiloxane from having a high molecular weight. Examples of the alkali metal carboxylate that can be used include sodium formate, potassium formate, sodium acetate, sodium propionate, potassium propionate, and the like, with sodium acetate being preferred. In the present invention, the amount of the alkali metal carboxylate used is in the range of 20 to 100 parts by weight, preferably 40 to 60 parts by weight, with respect to 100 parts by weight of water. This is because if the amount of the alkali metal carboxylate is less than 20 parts by weight, not only the organotrihalosilane is hydrolyzed but hydrogen halide formed as a by-product cannot be sufficiently captured, but also the polysiloxane has a high molecular weight and is gelled. This is because insoluble matter is generated. On the other hand, if it exceeds 80 parts by weight, not only the solubility of the alkali metal carboxylate in water but also the problem is uneconomical.

The stirring speed during the hydrolysis of the organotrihalosilane must be adjusted so that the two-phase interface between the aqueous phase and the organic phase can be maintained. This is because if the stirring speed is too fast, the interface will be disturbed and a suspension state of water and the organic solvent will be formed, and the solvent-soluble silsesquioxane will not be generated and gelation will occur.
The reaction temperature is 0 to 60 ° C, preferably 5 to 10 ° C
Is. This is because the water in the reaction system freezes at 0 ° C or lower and stirring becomes difficult, and when the temperature exceeds 60 ° C, the silsesquioxane produced is polymerized.

The method of adding the organotrihalosilane to the two-phase system is not particularly limited, but a method of gradually adding such as dropwise addition is preferable. The dripping rate was 1 for organotrihalosilane.
It is preferable to take about 1 hour per 0 g, because if the dropping rate is too fast, the temperature of the reaction system rises, making temperature control difficult. The reaction time is 1 to 3 hours, preferably 2 hours after the dropping. This is hydrolysis in less than 1 hour
This is because the condensation does not proceed sufficiently, and the silsesquioxane formed after 3 hours has a high molecular weight. After the reaction, the aqueous phase is removed, the organic phase is washed with water until the water becomes neutral, and then dehydrated with magnesium sulfate or the like.
The solvent is distilled off to obtain a silanol-terminated silsesquioxane ladder oligomer.

The silanol-terminated silsesquioxane ladder oligomer of the present invention is prepared by mixing the organotrihalosilane with a mixture of an alkali metal carboxylate prepared in a specific ratio, water, an organic solvent and an aprotic polar solvent. It can be obtained in good yield by the above-mentioned production method of dropping.

[0020]

EXAMPLES Next, the present invention will be further clarified with reference to examples, but the present invention is not limited to the examples. In addition, the molecular weights shown in this Example are GPC and N.
It was measured by MR. Example 1 A reaction vessel equipped with a stirrer, a dropping funnel, and a thermometer was charged with water 3
4.0 g and 17.2 g of sodium acetate were added and mixed. Next, 30.9 g of toluene and 6.7 g of tetrahydrofuran were added and mixed. When left to stand, two phases, an aqueous phase and an organic phase, were formed. The stirring speed was adjusted to such an extent that this two-phase interface could be maintained, and methyltrichlorosilane 4.23 was added thereto.
A mixture of g and 6.02 g of phenyltrichlorosilane was added dropwise from the dropping funnel over 1 hour. At the end of the dropping, the temperature of the reaction mixture reached 50 ° C., but when the stirring was continued thereafter, the temperature gradually decreased to room temperature. Stir for 2 hours after dropping,
The reaction solution was transferred to a separating funnel and the aqueous phase was removed. The organic phase was washed 6 times with 30 g of water, and it was confirmed that the wash water became neutral. Magnesium sulfate was added to the organic phase to dry it overnight, then this was filtered off, the solvent was removed under reduced pressure, and vacuum drying was carried out at 40 ° C. for 5 hours to obtain a ladder-type polysiloxane having silanol ends as a colorless solid. 5.18 g of an oligomer of

Number average molecular weight (Mn) of the obtained product
According to GPC, it was 1530 in terms of standard polystyrene, and the molecular weight distribution (Mw / Mn, Mw is the weight average molecular weight) was 6.63. ¹ H-NMR of the product was determined to be CDCl ₃
When measured in, SiMe around 0.14ppm,
A broad peak due to SiPh appeared at 6.8 to 7.8 ppm, and a peak believed to be due to SiOH and water appeared at 1.64 ppm. ¹ H-NMR of this oligomer was measured in dimethylsulfoxide-d _{6 and} found to be 1.64 ppm.
Peak disappears, a new peak due to water appears at 3.23 ppm, and the peak at 6.8 to 7.8 ppm is SiOH.
The signals of No. 1 and No. 2 overlapped and became large. From this, CDC
peak of 1.64ppm for in l ₃ was been only not a lining and by SiOH and water. Further, the ratio of Si substituents in the produced oligomer is Me: Ph = 10: 7 from the integral ratio, and Me is introduced to some extent preferentially. In addition, Me is a methyl group and Ph is a phenyl group.

Example 2 As in Example 1, 34.0 g of water, 1 part of sodium acetate
7.2 g, 30.9 g of toluene, and 6.7 g of 1,4-dioxane were added and mixed. When left to stand, two phases, an aqueous phase and an organic phase, were formed. The stirring speed was adjusted to such an extent that this two-phase interface could be maintained, and methyltrichlorosilane 4.23 was added thereto.
g and 6.02 g of phenyltrichlorosilane in 1 part
The mixture was dropped over a period of time and stirred for 2 hours. At the end of the dropping, the temperature of the reaction solution reached 45 ° C., but then gradually decreased to room temperature. The same treatment as in Example 1 was carried out to obtain 5.42 g of a colorless solid. When the product was analyzed by the same method as in Example 1, the number average molecular weight was 1200 and the molecular weight distribution was 7.2.
It was 0. The ratio of Si substituents in the produced oligomer is M
e: Ph = 10: 7.

Example 3 As in Example 1, 34.0 g of water, 1 part of sodium acetate
7.2 g, toluene 30.9 g, and 1,2-methoxyethane 6.7 g were added and mixed. When left to stand, two phases, an aqueous phase and an organic phase, were formed. The stirring speed was adjusted so that the two-phase interface could be maintained, and methyltrichlorosilane 4.2 was added thereto.
A mixture of 3 g and 6.02 g of phenyltrichlorosilane was added dropwise over 1 hour, and the mixture was stirred for 2 hours. At the end of the dropping, the temperature of the reaction solution reached 45 ° C., but then gradually decreased to room temperature. The same treatment as in Example 1 was carried out to obtain 5.07 g of a colorless solid. When the product was analyzed by the same method as in Example 1, the number average molecular weight was 1320 and the molecular weight distribution was 6.4.
It was 7. The ratio of Si substituents in the produced oligomer is M
e: Ph = 10: 7.

Example 4 As in Example 1, 34.0 g of water, 1 part of sodium acetate
7.2 g, toluene 30.9 g, and acetone 6.7 g were added and mixed. When left to stand, two phases, an aqueous phase and an organic phase, were formed. The stirring speed was adjusted to such an extent that the two-phase interface could be maintained, and a mixture of 4.23 g of methyltrichlorosilane and 6.02 g of phenyltrichlorosilane was added dropwise thereto over 1 hour and stirred for 2 hours. At the end of the dropping, the temperature of the reaction solution reached 50 ° C., but then gradually decreased to room temperature. The same treatment as in Example 1 was carried out to obtain 5.10 g of a colorless solid.
I got When the product was analyzed by the same method as in Example 1, the number average molecular weight was 1,070 and the molecular weight distribution was 4.90. The ratio of Si substituents in the resulting oligomer is Me: Ph =
It was 10: 6.

Example 5 As in Example 1, 34.0 g of water, 1 part of sodium acetate
7.2 g, toluene 30.9 g, and tetrahydrofuran 6.7 g were added and mixed, and the mixture was stood still to form two phases of an aqueous phase and an organic phase. The stirring speed was adjusted to such an extent that the two-phase interface could be maintained, and a mixture of methyltrichlorosilane 4.23 g and phenyltrichlorosilane 6.02 g was added thereto while keeping the internal temperature at 5 to 10 ° C. by cooling with an ice water bath. Drop 2
Stir for hours. The same treatment as in Example 1 was carried out to obtain 5.29 g of a colorless solid. When the product was analyzed by the same method as in Example 1, the number average molecular weight was 1,000 and the molecular weight distribution was 3.9.
It was 7. The ratio of Si substituents in the produced oligomer is M
e: Ph = 10: 7. By lowering the reaction temperature, both the molecular weight and the molecular weight distribution could be suppressed.

Comparative Example 1 As in Example 1, 34.0 g of water and 1 of sodium acetate
7.2 g, toluene 30.9 g, and iso-propanol 6.7 g were added and mixed, and the mixture was allowed to stand to form two phases, an aqueous phase and an organic phase. The stirring speed was adjusted to such an extent that the two-phase interface could be maintained, and a mixture of 4.23 g of methyltrichlorosilane and 6.02 g of phenyltrichlorosilane was added dropwise thereto over 1 hour, and the mixture was further stirred for 2 hours. The same treatment as in Example 1 was carried out to obtain 5.49 g of a colorless solid.

The number average molecular weight of the obtained product is GPC
According to the standard polystyrene, it was 702 and the molecular weight distribution was 1.61. Further, ¹ H-NMR of the product was measured in CDCl ₃ , and it was confirmed that SiMe,
A broad peak due to SiPh appeared at 6.8 to 7.9 ppm, and the ratio of Si substituents in the produced oligomer was Me: Ph = 10: 6 from the integration ratio. Further, signals by iso- propyl group and 1.2ppm (CH ₃₎ 4.2
It appeared in the vicinity of ppm (CH). Is also from ¹³ C-NMR
It was confirmed that an o-propyl group was included. GP
From the molecular weight obtained from C and the integration ratio of ¹ H-NMR, it was found that one molecule of this oligomer contained an average of 2 iso-propyl groups.

Application Example 1 A cured product was prepared using the silsesquioxane ladder oligomer obtained in the system of Example 4 to which acetone was added.
2 g of this ladder oligomer was dissolved in tetrahydrofuran. This is a cylindrical can with a double-sided tape attached to a polyimide film (cast into a diameter of 45 mm and a depth of 8 mm, covered with a lid, 50 ° C./40 hours, 80 ° C./10 hours, 1
Heat curing was performed in the order of 00 ° C./100 hours and 150 ° C./100 hours. As a result, a colorless and transparent cured product having a thickness of 0.8 to 0.9 mm was obtained. The bending test of this cured product was performed according to the bending test method using a small test piece of JIS standard (K7203). The measurement condition is span: 15 mm,
Indenter: 5R, fulcrum: 2R, test speed: 0.5mm
/ Min. As a result, the flexural modulus of the obtained cured product was 2.68 GPa and the maximum strength was 53.9 MPa.

Comparative Example 2 Glass Resin GR-100 obtained from Showa Denko KK
(Me / Ph = 2/1, Mn = 950, and polysilsesquioxane ladder oligomer having ethoxy group or hydrogen at the molecular end) was heat-cured in the same manner as in Application Example 1 to prepare a cured product. . The flexural modulus of this cured product was 1.
The strength was 54 GPa and the maximum strength was 30.9 MPa.

[0030]

INDUSTRIAL APPLICABILITY The silsesquioxane ladder oligomer of the present invention has a number average molecular weight of 500 to 2000, has a plurality of types of organic substituents on silicon, and has four terminal functional groups in one molecule, all of which are silanols. Therefore, it is soluble in various organic solvents, and when it is used, it has a characteristic that a cured product of silsesquioxane having no catalyst, heat resistance, and high elastic modulus can be obtained. Further, the production method of the present invention is characterized in that such a silsesquioxane ladder oligomer can be efficiently produced without gelation during production.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshifumi Hirose 7-2-3 Kaminomiya, Suma-ku, Hyogo Prefecture

Claims (8)

[Claims] 1. A general formula (1) (R ¹ is a monovalent hydrocarbon group, R ² is an aromatic hydrocarbon group, the number of R ¹ is R ¹
And 20 to 90% of the total number of R ² and l, m,
n is 0 or a positive number, and the average of these sums is 2 ≦ l + m
+ N ≦ 15. ), Number average molecular weight 500
~ 2000 silanol terminated silsesquioxane ladder oligomers. Embedded image 2. The silanol-terminated silsesquioxane ladder oligomer according to claim 1, wherein R ¹ is a monovalent hydrocarbon group having 1 to 3 carbon atoms. 3. The silanol-terminated silsesquioxane ladder oligomer according to claim 1, wherein R ¹ is a methyl group and R ² is a phenyl group. 4. The silanol-terminated silsesquioxane ladder oligomer according to claim 1, which has a number average molecular weight of 700 to 1500. 5. An alkali metal carboxylate and an aprotic polar organic solvent are dissolved in a two-phase system consisting of an organic solvent phase and an aqueous phase to obtain the formula (2): R ¹ SiX ₃ and the formula (3): R.
² SiX ₃ (R ¹ is a monovalent hydrocarbon group, R ² is an aromatic hydrocarbon group, X is a halogen atom.) A mixture of organotrihalosilane represented by by cohydrolysis The method for producing a silanol-terminated silsesquioxane ladder oligomer according to claim 1, wherein the silanol is condensed. 6. The silanol-terminated silsesquioxane according to claim 5, wherein R ¹ is a monovalent hydrocarbon group having 1 to 3 carbon atoms, R ² is a phenyl group, and X is a chlorine atom or a bromine atom. Method for producing ladder oligomer. 7. The method for producing a silanol-terminated silsesquioxane ladder oligomer according to claim 5, wherein R ¹ is a methyl group, R ² is a phenyl group, and X is a chlorine atom. 8. The method for producing a silanol-terminated silsesquioxane ladder oligomer according to claim 5, which has a number average molecular weight of 700 to 1500.