Method for producing silane compound polymer

Abstract

To provide a method capable of efficiently producing a silane compound polymer having an unsubstituted aryl group or an aryl group having a substituent which is liquid at room temperature and has thermosetting properties.SOLUTION: There is provided a method for producing a silane compound polymer which comprises a step (step PO) of subjecting an alkoxysilane compound to hydrolysis polycondensation in the presence of water and an acid catalyst, wherein at least one of the alkoxysilane compounds is a trifunctional alkoxysilane compound represented by the following formula (1) [R1 represents an unsubstituted aryl group having 6 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms which has a substituent, OR represents an alkoxy group, ORs may be the same or different] and the molar ratio M between water and the alkoxy group is 0.46 to 0.86.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a silane compound polymer.

Background Art

[0002] Conventionally, curable compositions have been variously improved according to their uses and have been widely used industrially as raw materials for optical components, molded articles, adhesives, coating agents, and the like. In addition, curable compositions have also attracted attention as compositions for fixing optical elements, such as adhesives for fixing optical elements and sealing materials for fixing optical elements.

[0003] Optical elements include various lasers such as semiconductor lasers (LDs), light-emitting elements such as light-emitting diodes (LEDs), light-receiving elements, compound optical elements, optical integrated circuits, and the like. In recent years, optical elements that emit blue light or white light, whose peak wavelengths of light emission are shorter, have been developed and widely used. The brightness of such light-emitting elements with short peak wavelengths of light emission has advanced dramatically, and along with this, the amount of heat generated by the optical elements tends to become even larger.

[0004] However, with the recent increase in the brightness of optical elements, there has been a problem that the cured product of the composition for fixing optical elements is exposed to light with higher energy or heat at a higher temperature generated from the optical element for a long time, resulting in a decrease in adhesive strength. To solve this problem, Patent Documents 1 to 3 have proposed compositions for fixing optical elements mainly composed of polysilsesquioxane compounds.

[0005] In particular, polysilsesquioxane compounds containing many aryl groups tend to have a higher refractive index than polysilsesquioxane compounds containing many alkyl groups. Therefore, when a fixing material with a high refractive index is required to improve the light extraction efficiency, a polysilsesquioxane compound containing many aryl groups may be used as the main component of the composition for fixing optical elements.

[0006] By the way, in curable compositions such as these compositions for fixing optical elements, when a polysilsesquioxane compound that is solid at room temperature is used as a main component, a solvent is usually added to the curable composition in order to improve the coatability of the curable composition. However, in recent years, solventless curable compositions have been desired from the viewpoint of reducing environmental impact. For this reason, various studies have been conducted to synthesize polysilsesquioxane compounds that are liquid at room temperature.

[0007] For example, Patent Document 4 describes a method for producing a polysilsesquioxane liquid including hydrolyzing and polycondensing a mixture composed of a trifunctional silicon alkoxide, water, and an acid catalyst without using an organic solvent, and then removing the alcohol generated by hydrolysis of the trifunctional silicon alkoxide. In the examples of Patent Document 4, various polysilsesquioxane liquids are produced using 3 moles of water with respect to 1 mole of the trifunctional silane compound.

[0008] Patent Document 5 describes a polysilsesquioxane liquid containing a polysilsesquioxane having a specific repeating unit as a main component. In the production examples of Patent Document 5, a polysilsesquioxane liquid is produced using 3 moles of water with respect to 1 mole of the trifunctional silane compound.

[0009] Patent Document 6 describes a condensation reaction type silicone composition containing a polysilsesquioxane or the like that is liquid at room temperature. In Production Example 1 of Patent Document 6, a liquid polysilsesquioxane is produced using 136.2 parts of methyltrimethoxysilane and 10.8 parts of water (0.6 mole of water with respect to 1 mole of methyltrimethoxysilane). In Production Example 2 of Patent Document 6, a liquid polysilsesquioxane is produced using 136.2 parts of methyltrimethoxysilane and 16.2 parts of water (0.9 mole of water with respect to 1 mole of methyltrimethoxysilane).

[0010] In addition, in relation to the present invention, Patent Document 7 discloses a copolymer of phenyltrialkoxysilane and alkyltrialkoxysilane. However, all of the silane compound polymers described in this document are solids (polysilsesquioxane glass).

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0012] As described above, Patent Documents 4 to 6 describe methods for producing a silane compound polymer that is liquid at room temperature. However, according to the studies of the present inventors, depending on the type of monomer (alkoxysilane compound) used, a silane compound polymer that is liquid at room temperature may not be obtained even when the reaction conditions described in these documents are used. In fact, in the examples of Patent Document 7, a polycondensation reaction of a trifunctional alkoxysilane is carried out under substantially the same reaction conditions as those disclosed in Patent Document 4, but a solid silane compound polymer is obtained. In addition, only silane compounds that are inferior in thermosetting properties can be obtained even if they are liquids, and it may be necessary to add a curing catalyst when curing the obtained silane compound polymer. The present invention has been made for the purpose of solving these problems, and is a silane compound polymer having an unsubstituted aryl group or an aryl group having a substituent, which is a liquid at room temperature (25 ° C, the same hereinafter), and An object of the present invention is to provide a method capable of efficiently producing a silane compound polymer having thermosetting properties. In the present invention, "liquid at room temperature" means a substance having fluidity at 25 ° C. Further, "thermosetting property" means a property of curing only by heating even in the absence of a curing catalyst.

Means for Solving the Problems

[0013] The present inventors intensively studied the hydrolysis polycondensation reaction of alkoxysilane compounds in order to solve the above problems. As a result, when hydrolytic polycondensing an alkoxysilane compound in the presence of water and an acid catalyst, by adjusting the amount of water added, a silane compound polymer that is liquid at room temperature and has thermosetting properties is obtained. The present inventors have found this and completed the present invention.

[0014] Thus, according to the present invention, there is provided a method for producing a silane compound polymer of the following [1] to

[12] .

[0015] (1) A method for producing a silane compound polymer having a step (step PO) of hydrolytic polycondensing an alkoxysilane compound in the presence of water and an acid catalyst, wherein at least one of the alkoxysilane compounds is represented by the following formula (1)

[0016]

Chemical formula

[0017] 〔R 1represents an unsubstituted aryl group having 6 to 12 carbon atoms or a substituted aryl group having 6 to 12 carbon atoms. OR represents an alkoxy group. ORs may be the same as or different from each other. 〕 It is a trifunctional alkoxysilane compound represented by the formula, and the amount of the trifunctional alkoxysilane compound represented by the formula (1) is more than 50 mol% and 100 mol% or less based on the total amount of the trifunctional alkoxysilane compound, and the molar ratio M of water to alkoxy group derived from the following formula (F1) is 0.46 to 0.86. A method for producing a silane compound polymer, characterized in that

[0018] [Number]

[0019] [M H2O is the number of moles of water added to the reaction system, and M OR is the total number of moles of alkoxy groups in the alkoxysilane compound. 〕 [2] The method for producing a silane compound polymer according to [1], wherein the amount of the trifunctional alkoxysilane compound is 80 to 100 mol% in the whole alkoxysilane compound. [3] The method for producing a silane compound polymer according to [1] or [2], wherein the step PO includes a step of promoting hydrolysis of the alkoxysilane compound in the presence of water and an acid catalyst (step PO-I) and a step of adjusting the molecular weight of the silane compound polymer (step PO-II). [4] The method for producing a silane compound polymer according to [3], wherein the reaction conditions of the step PO-I are 0 to 50 ° C. and 10 minutes to 2 hours. [5] The method for producing a silane compound polymer according to [3] or [4], wherein the step PO-II is carried out by adding 0.1 to 20 equivalents of a base to the acid catalyst used in the step PO-I into the reaction system. [6] The method for producing a silane compound polymer according to any one of [3] to [5], wherein the reaction conditions of the step PO-II are 20 to 85 ° C. and 20 minutes to 48 hours. The production method of the silane compound polymer according to any one of [3] to [6], wherein at least step PO-II is carried out under stirring conditions. The production method of the silane compound polymer according to any one of [3] to [7], wherein at least step PO-II is carried out in the presence of an organic solvent. The production method of the silane compound polymer according to any one of [3] to [8], wherein at least step PO-II is carried out in an open system. The production method of the silane compound polymer according to any one of [1] to [9], wherein the silane compound polymer is liquid at room temperature and has thermosetting properties. The production method of the silane compound polymer according to

[10] , wherein the silane compound polymer has an alkoxy group residual rate of 2.5 to 25%. The production method of the silane compound polymer according to

[10] or

[11] , wherein the silane compound polymer has a mass average molecular weight (Mw) of 500 to 10,000.

Advantages of the Invention

[0020] According to the present invention, there is provided a method capable of efficiently producing a silane compound polymer that is liquid at room temperature and has thermosetting properties.

Embodiments for Carrying Out the Invention

[0021] The production method of the silane compound polymer of the present invention is a production method of a silane compound polymer having a step (step PO) of subjecting an alkoxysilane compound to hydrolysis polycondensation in the presence of water and an acid catalyst, wherein at least one kind of the alkoxysilane compound is a trifunctional alkoxysilane compound represented by the formula (1), and the molar ratio M of water to alkoxy group derived from the formula (F1) is 0.46 to 0.86.

[0022] 〔Alkoxysilane compound〕 In the production method of the silane compound polymer of the present invention, an alkoxysilane compound is used as a monomer. Examples of the alkoxysilane compound include monofunctional alkoxysilane compounds such as triphenylmethoxysilane, difunctional alkoxysilane compounds such as diphenyldimethoxysilane, trifunctional alkoxysilane compounds such as phenyltrimethoxysilane, and tetrafunctional alkoxysilane compounds such as tetramethoxysilane. Among these, in the method for producing a silane compound polymer of the present invention, at least one kind of the alkoxysilane compound is a trifunctional alkoxysilane compound represented by the following formula (1).

[0023]

Chemical formula

[0024] In formula (1), R 1 represents an unsubstituted aryl group having 6 to 12 carbon atoms or a substituted aryl group having 6 to 12 carbon atoms. OR represents an alkoxy group. OR may be the same as or different from each other.

[0025] In the method for producing a silane compound polymer of the present invention, by using a trifunctional silane compound as a monomer, a silane compound polymer that is liquid at room temperature and has thermosetting properties can be easily obtained. In particular, by using the trifunctional silane compound represented by formula (1), a silane compound polymer that gives a cured product having a relatively high refractive index can be obtained.

[0026] R 1 The carbon number of the "unsubstituted aryl group having 6 to 12 carbon atoms" represented by is preferably 6. Examples of the "unsubstituted aryl group having 6 to 12 carbon atoms" include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0027] R 1 The carbon number of the "substituted aryl group having 6 to 12 carbon atoms" represented by is preferably 6. Note that this carbon number means the carbon number of the part excluding the substituent (the aryl group part). Therefore, R 1When it is an "aryl group having 6 to 12 carbon atoms with a substituent", R 1 may have more than 12 carbon atoms. Examples of the aryl group of the "aryl group having 6 to 12 carbon atoms with a substituent" include the same ones as those shown as the "unsubstituted aryl group having 6 to 12 carbon atoms".

[0028] The number of atoms of the substituent (excluding the number of hydrogen atoms) of the "aryl group having 6 to 12 carbon atoms with a substituent" is usually 1 to 30, preferably 1 to 20. Examples of the substituent of the "aryl group having 6 to 12 carbon atoms with a substituent" include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, isooctyl group; halogen atoms such as fluorine atom, chlorine atom, bromine atom; alkoxy groups such as methoxy group, ethoxy group; and the like.

[0029] Among these, R 1 is preferably an unsubstituted aryl group having 6 to 12 carbon atoms. In particular, the method for producing a silane compound polymer of the present invention is preferably used when hydrolytic polycondensing an alkoxysilane compound in which R 1 is a phenyl group. That is, conventionally, it has been very difficult to produce a silane compound polymer that is liquid at room temperature and has thermosetting properties using phenyltrialkoxysilane as a monomer. However, according to the method for producing a silane compound polymer of the present invention, even when phenyltrialkoxysilane is used as a monomer, a silane compound polymer that is liquid at room temperature and has thermosetting properties can be efficiently produced.

[0030] The carbon number of the alkoxy group represented by OR is preferably 1 to 6, more preferably 1 to 3. Examples of the alkoxy group represented by OR include methoxy group, ethoxy group, propoxy group, and the like.

[0031] Specific examples of the trifunctional alkoxysilane compound represented by formula (1) include aryltrialkoxysilane compounds such as phenyltrimethoxysilane, phenyltriethoxysilane, and phenyltripropoxysilane; Substituted aryltrialkoxysilane compounds such as 4-methoxyphenyltrimethoxysilane, 4-methoxyphenyltriethoxysilane, and 4-methoxyphenyltripropoxysilane; and the like. These trifunctional alkoxysilane compounds can be used alone or in combination of two or more.

[0032] In the method for producing a silane compound polymer of the present invention, the amount of the trifunctional silane compound represented by formula (1) used is more than 50 mol% and 100 mol% or less based on the total amount of the trifunctional alkoxysilane compounds. By having the amount of the trifunctional silane compound represented by formula (1) be more than 50 mol% and 100 mol% or less based on the total amount of the trifunctional alkoxysilane compounds, a silane compound polymer that gives a cured product having a relatively high refractive index can be obtained. Thus, in the method for producing a silane compound polymer of the present invention, the amount of the trifunctional silane compound represented by formula (1) can be appropriately adjusted so that the silane compound polymer and its cured product have the desired refractive index. When a silane compound polymer that gives a cured product having a higher refractive index is required, the amount of the trifunctional silane compound represented by formula (1) used is preferably 70 to 100 mol%, more preferably 90 to 100 mol%, based on the total amount of the trifunctional alkoxysilane compounds.

[0033] In the method for producing a silane compound polymer of the present invention, when using a trifunctional silane compound other than the trifunctional silane compound represented by formula (1), examples of such a trifunctional silane compound include the trifunctional silane compound represented by the following formula (2).

[0034]

Chemical formula

[0035] In formula (2), R 2 represents an unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted alkyl group having 1 to 10 carbon atoms. OR'represents an alkoxy group. OR'may be the same as or different from each other.

[0036] R 2 The number of carbon atoms of the "unsubstituted alkyl group having 1 to 10 carbon atoms" represented by is preferably 1 to 6, more preferably 1 to 3. Examples of the "unsubstituted alkyl group having 1 to 10 carbon atoms" include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, and the like.

[0037] R 2 The number of carbon atoms of the "substituted alkyl group having 1 to 10 carbon atoms" represented by is preferably 1 to 6, more preferably 1 to 3. Note that this number of carbon atoms means the number of carbon atoms of the part excluding the substituent (alkyl group part). Therefore, when R 2 is a "substituted alkyl group having 1 to 10 carbon atoms", the number of carbon atoms of R 2 may exceed 10. Examples of the alkyl group of the "substituted alkyl group having 1 to 10 carbon atoms" include the same ones as those shown as the "unsubstituted alkyl group having 1 to 10 carbon atoms".

[0038] The number of atoms of the substituent (excluding the number of hydrogen atoms) of the "substituted alkyl group having 1 to 10 carbon atoms" is usually 1 to 30, preferably 1 to 20. Examples of the substituent of the "substituted alkyl group having 1 to 10 carbon atoms" include halogen atoms such as a fluorine atom, a chlorine atom, and a bromine atom; aryl groups such as a phenyl group; and the like.

[0039] The number of carbon atoms of the alkoxy group represented by OR'is preferably 1 to 6, more preferably 1 to 3. Examples of the alkoxy group represented by OR'include a methoxy group, an ethoxy group, a propoxy group, and the like.

[0040] Specific examples of the trifunctional alkoxysilane compound represented by formula (2) include alkyltrialkoxysilane compounds such as methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and ethyltripropoxysilane; Substituted alkyltrialkoxysilane compounds such as 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, and 3,3,3-trifluoropropyltripropoxysilane; and the like. These trifunctional alkoxysilane compounds can be used alone or in combination of two or more.

[0041] In the method for producing the silane compound polymer of the present invention, the amount of the trifunctional alkoxysilane compound used is preferably 80 to 100 mol%, more preferably 85 to 100 mol%, and still more preferably 90 to 100 mol% in the total alkoxysilane compounds. When the amount of the trifunctional alkoxysilane compound used is 80 mol% or more in the total alkoxysilane compounds, it becomes easy to obtain a silane compound polymer that is liquid at room temperature and has thermosetting properties.

[0042] 〔Water〕 In the method for producing the silane compound polymer of the present invention, water is used to hydrolyze the alkoxysilane compound. In the method for producing the silane compound polymer of the present invention, the amount of water used is extremely important in order to obtain a silane compound polymer that is liquid at room temperature and has thermosetting properties. That is, in the method for producing the silane compound polymer of the present invention, the molar ratio M of water derived from the following formula (F1) to the alkoxy group is 0.46 to 0.86, preferably 0.48 to 0.80, and more preferably 0.50 to 0.70.

[0043]

Number

[0044] In formula (F1), M H2O is the amount of substance (number of moles) of water added to the reaction system, and M OR is the total number of alkoxy groups (total number of moles) in the alkoxysilane compound. For example, when 1 mole of phenyltrialkoxysilane is added with 1 mole of water, the value of the molar ratio M is 1 / 3 (0.33).

[0045] When the molar ratio M exceeds 0.86, there is too much water added to the reaction system. When there is too much water added to the reaction system, a silane compound polymer that is solid at room temperature is likely to be formed. When the molar ratio M is less than 0.46, there is too little water added to the reaction system. When there is too little water added to the reaction system, a silane compound polymer with poor thermosetting properties is likely to be formed.

[0046] It is considered that when the molar ratio M is within the above range, a silane compound polymer having the desired physical properties can be obtained because the amount of water added to the reaction system affects the amount of alkoxy groups in the silane compound polymer to be formed. That is, as will be described later, in the silane compound polymer, it is considered that the alkoxy group contributes to the liquefaction of the silane compound polymer, and the hydroxy group contributes to the thermosetting property of the silane compound polymer. Therefore, by performing the hydrolysis reaction of the alkoxysilane compound so that an appropriate amount of alkoxy groups remain, a silane compound polymer having the desired physical properties can be efficiently produced.

[0047] [Acid catalyst] In the method for producing the silane compound polymer of the present invention, an acid catalyst is used as the catalyst. Examples of the acid catalyst include inorganic acids such as phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, and nitric acid; organic acids such as citric acid, acetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid; and the like. Among these, at least one selected from phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, citric acid, acetic acid, and methanesulfonic acid is preferable as the acid catalyst.

[0048] The amount of the acid catalyst used is usually 0.05 to 10 mol%, preferably 0.1 to 5 mol%, based on the total amount of the alkoxysilane compound. When the amount of the acid catalyst used is within the above range, it becomes easier to adjust the molecular weight of the silane compound polymer.

[0049] [Step of hydrolytic polycondensation of alkoxysilane compound (Step PO)] The method for producing the silane compound polymer of the present invention includes a step (Step PO) of hydrolytic polycondensation of an alkoxysilane compound in the presence of water and an acid catalyst.

[0050] Step PO can be carried out, for example, by putting an alkoxysilane compound, water, and an acid catalyst into a reaction vessel and stirring the resulting mixture. In addition, an organic solvent may be present in the reaction vessel in addition to these components. Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol, and t-butyl alcohol; and the like. These solvents can be used alone or in combination of two or more. When an organic solvent is used in Step PO, the organic solvent is preferably used in an amount of 0.05 to 3 times, more preferably 0.1 to 1.5 times, based on the volume of the alkoxysilane compound.

[0051] As long as the requirements regarding the above-mentioned "molar ratio M of water to alkoxy group" are satisfied, the reaction conditions of step PO are not particularly limited. The reaction temperature of step PO is generally 0 to 85°C, preferably 15 to 75°C. The reaction time of step PO is generally from 30 minutes to 50 hours, preferably 1 to 24 hours.

[0052] Step PO may be carried out under constant conditions from start to end (that is, it may have one step), or may have a plurality of steps with different reaction conditions. Since a silane compound polymer with the target molecular weight can be efficiently produced, step PO preferably includes a step (step PO-I) of promoting the hydrolysis of an alkoxysilane compound in the presence of water and an acid catalyst, and a step (step PO-II) of adjusting the molecular weight of the silane compound polymer.

[0053] Step PO-I is a step of promoting the hydrolysis of an alkoxysilane compound in the presence of water and an acid catalyst. Step PO-I can be carried out, for example, by putting an alkoxysilane compound, water, and an acid catalyst into a reaction vessel and stirring the resulting mixture. In addition, an organic solvent may be present in the reaction vessel in addition to these components. Examples of the organic solvent include those exemplified above as the organic solvent for step PO. When an organic solvent is used in step PO-I, an organic solvent is preferably used in an amount of 0.05 to 1 times, more preferably 0.1 to 0.5 times, based on the volume of the alkoxysilane compound.

[0054] As long as the requirements regarding the above-mentioned "molar ratio M of water to alkoxy group" are satisfied, the reaction conditions of step PO-I are not particularly limited. The reaction temperature of step PO-I is generally 0 to 50°C, preferably 15 to 35°C. The reaction time of step PO-I is generally from 10 minutes to 2 hours, preferably 15 to 90 minutes.

[0055] The water added for hydrolysis of the alkoxysilane compound is preferably completely consumed at the end of Step PO-I. For example, regarding the alkoxysilane compound represented by the above formula (1), the consumption amount of water can be estimated by measuring the H-NMR of the reaction product and comparing the amount of " 1 Si-R 1 " with the amount of " Si-OR

[0056] Step PO-II is a step of adjusting the molecular weight of the silane compound polymer. That is, Step PO-II is a step of advancing the polycondensation reaction of the reaction product of Step PO-I in order to produce a silane compound polymer having a target molecular weight.

[0057] In order to adjust the molecular weight of the silane compound polymer, it is preferable to add a base to the reaction system as needed when performing Step PO-II. By adding a relatively large amount of base or increasing the reaction time of Step PO-II, there is a tendency to obtain a silane compound polymer that is liquid at room temperature, has thermosetting properties, and has a relatively large molecular weight. Also, in Step PO-I, by adjusting the amount of the acid catalyst and the reaction temperature to promote the hydrolysis reaction of the alkoxysilane compound, there is a tendency to obtain a silane compound polymer with a large molecular weight. On the other hand, by adding a relatively small amount of base or shortening the reaction time of Step PO-II, there is a tendency to obtain a silane compound polymer that is liquid at room temperature, has thermosetting properties, and has a relatively small molecular weight. Also, in Step PO-I, by adjusting the amount of the acid catalyst and the reaction temperature to make the hydrolysis reaction of the alkoxysilane compound proceed in a somewhat suppressed manner, there is a tendency to obtain a silane compound polymer with a small molecular weight.

[0058] When a base is added to the reaction system during the execution of Step PO-II, the addition amount is preferably 0.1 to 20 equivalents, more preferably 0.5 to 8 equivalents, relative to the acid catalyst used in Step PO-I. By adding the above amount of base to the reaction system, a silane compound polymer having a target molecular weight can be efficiently produced.

[0059] Examples of the base include aqueous ammonia; organic bases such as trimethylamine, triethylamine, lithium diisopropylamide, lithium bis(trimethylsilyl)amide, pyridine, 1,8-diazabicyclo[5.4.0]-7-undecene, aniline, picoline, 1,4-diazabicyclo[2.2.2]octane, imidazole; organic hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide; metal alkoxides such as sodium methoxide, sodium ethoxide, sodium t-butoxide, potassium t-butoxide; metal hydrides such as sodium hydride, calcium hydride; metal hydroxides such as sodium hydroxide, potassium hydroxide, calcium hydroxide; metal carbonates such as sodium carbonate, potassium carbonate, magnesium carbonate; metal hydrogen carbonates such as sodium hydrogen carbonate, potassium hydrogen carbonate; and the like.

[0060] The reaction conditions of Step PO-II are not particularly limited. The reaction temperature of Step PO-II is usually 20 to 85°C, preferably 24 to 75°C. The reaction time of Step PO-II is usually from 20 minutes to 48 hours, preferably 1 to 24 hours.

[0061] Conventionally, when producing a silane compound polymer, an "aging step" may be provided to allow the polycondensation reaction to proceed sufficiently. Regarding this aging step, for example, in paragraph (0020) of Patent Document 4, it is described that "a mixture consisting of a trifunctional silicon alkoxide, water, and an acid catalyst is preferably held at a temperature of about 20 to 60°C for 24 hours to perform hydrolysis and polycondensation." Actually, in the examples of Patent Document 4, in a sealed container, a mixture consisting of a trifunctional silicon alkoxide, water, and an acid catalyst was stirred at 20°C for 3 hours and then aged (left standing) at 60°C for 24 hours to produce a silane compound polymer.

[0062] Step PO-II is intended to allow the polycondensation reaction to proceed sufficiently in the same manner as the aging step. However, unlike the aging step, it is preferably carried out with stirring. That is, the aging step of allowing the mixture after the hydrolysis reaction to stand is considered to be a process suitable for the polycondensation reaction after adding a sufficient amount of water (3 equivalents of water relative to the trifunctional silicon alkoxide) and substituting almost all alkoxy groups with hydroxy groups, as in the examples of Patent Document 4. On the other hand, in the method for producing a silane compound polymer of the present invention, since the hydrolysis of the alkoxysilane compound is carried out under the condition that the molar ratio M of water to the alkoxy group is in the range of 0.46 to 0.86, even when the added water is completely consumed by hydrolysis, alkoxy groups remain in the reaction product of Step PO-I. Thus, since Si-OH and Si-OR are mixed in the reaction product of Step PO-I, it is preferable to stir the reaction system in order to efficiently carry out the polycondensation reaction of this reaction product and obtain a silane compound polymer with the desired molecular weight.

[0063] Step PO-II is preferably carried out in the presence of an organic solvent. By carrying out Step PO-II in the presence of an organic solvent, the reaction system can be sufficiently stirred, and the polycondensation reaction of the reaction product of Step PO-I can proceed sufficiently. In addition, since the polycondensation reaction of the reaction product of Step PO-I can be carried out under dilution conditions, the molecular weight can be adjusted with good reproducibility.

[0064] Examples of the organic solvent include those exemplified above as the organic solvent in step PO. Therefore, when step PO-I is carried out in the presence of an organic solvent, step PO-II can be carried out using that organic solvent as it is. On the other hand, when step PO-I is carried out in the absence of an organic solvent, step PO-II can be carried out in the presence of an organic solvent by adding an organic solvent to the reaction mixture obtained in step PO-I. When an organic solvent is used in step PO-II, the organic solvent is preferably used in an amount of 0.05 to 3 times, more preferably 0.1 to 1.5 times, based on the volume of the alkoxysilane compound used in step PO-I.

[0065] Step PO-II is preferably carried out in an open system. By carrying out step PO-II in an open system, water and alcohol, which are the products in step PO, are easily released outside the reaction system, so that it is possible to avoid the polycondensation reaction being inhibited by water and alcohol. Further, when step PO-II is carried out in the presence of an organic solvent, an excessive pressurized state can be suppressed, so that the polycondensation reaction can proceed safely. The open system means a system in which the reaction system and the surrounding system are not completely blocked and are in a state where molecular movement is possible between them.

[0066] [Step of purifying the silane compound polymer (step PU)] In the method for producing a silane compound polymer of the present invention, it is preferable to carry out a step of purifying the silane compound polymer (step PU) after step PO. By carrying out step PU, a high-purity silane compound polymer can be obtained. Such a silane compound polymer is more suitable as a curable component of a curable composition such as a composition for fixing an optical element.

[0067] Examples of step PU include a purification step by a solvent extraction method. Examples of the purification process by the solvent extraction method include those having the following steps. (Step PU-I) A step of adding a water-immiscible organic solvent or water to the reaction mixture obtained in step PO as necessary, stirring the mixture, and then allowing it to stand to separate it into an organic phase and an aqueous phase (Step PU-II) A step of separating the organic phase formed in step PU-I and, if necessary, washing the organic phase with water (Step PU-III) A step of drying the organic phase separated in step PU-II (Step PU-IV) A step of removing the solvent from the organic phase dried in step PU-III

[0068] In step PU-I, as necessary, a solvent such as a water-immiscible organic solvent or water is added to the reaction mixture obtained in step PO so that the reaction mixture separates into an organic phase and an aqueous phase. The amount of the solvent added and the type of the organic solvent are not particularly limited as long as the reaction mixture obtained in step PO separates into an organic phase and an aqueous phase.

[0069] The silane compound polymer is usually contained in the organic phase. Therefore, in step PU-II, the organic phase formed in step PU-I is separated. Thereafter, the organic phase may be washed with water according to a conventional method.

[0070] In step PU-III, the organic phase is dried according to a conventional method such as adding magnesium sulfate.

[0071] In step PU-IV, the solvent is removed from the organic phase. The removal of the solvent can be carried out according to a conventional method such as concentration treatment with an evaporator or vacuum drying treatment.

[0072] [Silane Compound Polymer] According to the method for producing a silane compound polymer of the present invention, a silane compound polymer that is liquid at room temperature and has thermosetting properties can be efficiently produced. A silane compound polymer that is liquid at room temperature and has thermosetting properties is suitably used as a curable component of a curable composition that does not contain an organic solvent or a curing catalyst. Hereinafter, the silane compound polymer obtained by the production method of the silane compound polymer of the present invention may be referred to as "silane compound polymer (A)".

[0073] The silane compound polymer (A) preferably has a viscosity at 25 ° C of 15,000 Pa·s or less, more preferably 5,000 Pa·s or less, still more preferably 4,000 Pa·s or less, and particularly preferably 2,000 Pa·s or less. The silane compound polymer (A) having a viscosity at 25 ° C of 15,000 Pa·s or less is more suitable as a curable component of a curable composition that does not contain an organic solvent. Also, there is no particular lower limit for the viscosity of the silane compound polymer (A) at 25 ° C, but it is usually 0.3 Pa·s or more. Therefore, the silane compound polymer (A) preferably has a viscosity at 25 ° C of 0.3 to 15,000 Pa·s.

[0074] In this specification, the "viscosity at 25 ° C" refers to the viscosity with respect to a shear rate of 2.2 s using a cone plate with a cone radius (radius of the bottom surface of the cone) of 12.5 mm and a cone angle of 0.5 degrees. -1 However, when it exceeds 50 Pa·s in this measurement, the "viscosity at 25 ° C" refers to the viscosity with respect to an angular frequency of 2.0 rad / s using a parallel plate with a radius of 12.5 mm.

[0075] When the silane compound polymer (A) is subjected to the thermosetting test described in the examples, it is preferably 1500 seconds or less, and more preferably 1000 seconds or less. The silane compound polymer (A) having a result of this thermosetting test of 1500 seconds or less is more suitable as a curable component of a curable composition that does not contain a curing catalyst. Also, there is no particular lower limit for this thermosetting test, but it is usually 100 seconds or more. Therefore, when the silane compound polymer (A) is subjected to the thermosetting test described in the examples, those with a time of 100 to 1500 seconds are preferred.

[0076] The residual ratio of the alkoxy group in the silane compound polymer (A) is preferably 2.5 to 25%, more preferably 3.0 to 20%. The residual ratio of the alkoxy group in the silane compound polymer (A) represents the degree to which the alkoxy group contained in the alkoxysilane compound used as a monomer remains in the silane compound polymer (A). The silane compound polymer (A) with an alkoxy group residual ratio of 2.5% or more tends to become liquid at room temperature. The silane compound polymer (A) with an alkoxy group residual ratio of 25% or less tends to have sufficient thermosetting properties.

[0077] The residual ratio of the alkoxy group is of the silane compound polymer (A) 1 It can be calculated by measuring the 1H-NMR. For example, when the silane compound polymer (A) is produced using phenyltrimethoxysilane, by measuring the 1H-NMR of the silane compound polymer (A) and determining the ratio of the phenyl group to the methoxy group based on the peak area ratio, the residual ratio of the alkoxy group in the silane compound polymer (A) can be calculated. 1 Incidentally, since the silane compound polymer (A) is soluble in various organic solvents such as ketone solvents such as acetone; aromatic hydrocarbon solvents such as benzene; sulfur-containing solvents such as dimethyl sulfoxide; ether solvents such as tetrahydrofuran; ester solvents such as ethyl acetate; halogen-containing solvents such as chloroform; and mixed solvents composed of two or more of these, the NMR of the silane compound polymer (A) in a solution state can be measured using these solvents.

[0078] As described above, the method for producing the silane compound polymer of the present invention is to subject an alkoxysilane compound to hydrolysis polycondensation under the condition that the molar ratio M of water to the alkoxy group is 0.46 to 0.86. By subjecting an alkoxysilane compound to hydrolysis polycondensation under such conditions, a silane compound polymer (A) can be produced which has a well-balanced alkoxy group contributing to the liquefaction of the silane compound polymer and a hydroxy group contributing to thermosetting, is liquid at room temperature, and has thermosetting properties.

[0079] The mass average molecular weight (Mw) of the silane compound polymer (A) is preferably from 500 to 10,000, more preferably from 600 to 5,000, and still more preferably from 700 to 3,000. The molecular weight distribution (Mw / Mn) of the silane compound polymer (A) is not particularly limited, but is usually from 1.00 to 10.00, preferably from 1.10 to 6.00, and more preferably from 1.15 to 4.00. The silane compound polymer (A) having a mass average molecular weight and a molecular weight distribution (Mw / Mn) within the above ranges is suitably used as a curable component of a curable composition. The mass average molecular weight (Mw) and the number average molecular weight (Mn) can be determined, for example, as standard polystyrene conversion values by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0080] As described above, the silane compound polymer (A) having the desired molecular weight can be efficiently produced by using an appropriate amount of an acid catalyst and performing step PO-I and step PO-II in step PO.

[0081] The silane compound polymer (A) has a repeating unit represented by the following formula (3).

[0082]

Chemical formula

[0083] In formula (3), R 1 represents the same meaning as described above. O 1 / 2 means that an oxygen atom is shared with an adjacent repeating unit.

[0084] As shown in formula (3), the silane compound polymer (A) generally has a partial structure called a T site, in which three oxygen atoms are bonded to a silicon atom and one other group (R 1 represented by the formula) is bonded. Examples of the T site contained in the silane compound polymer (A) include those represented by the following formulas (4) to (6).

[0085]

Chemical formula

[0086] In formulas (4) to (6), R 1 represents the same meaning as described above. X 1 ~X 3 each independently represents a hydrogen atom or an alkyl group. Examples of the alkyl group of X 1 ~X 3 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, etc. In the above formulas (4) to (6), * is bonded to an Si atom.

[0087] As described in Patent Document 6, the content ratios of the T1 site represented by the formula (4), the T2 site represented by the formula (5), and the T3 site represented by the formula (6) can be determined by measuring the Si-NMR of the silane compound polymer (A) in a solution state according to a conventional method. 29 As shown in formulas (4) to (6), the T3 site has three adjacent Si atoms, the T2 site has two adjacent Si atoms, while the T1 site has only one adjacent Si atom. Therefore, the T1 site tends to constitute the terminal part of the silane compound polymer (A) and is an important site when interacting with other molecules. ​The state (liquid or solid) and thermosetting properties of the silane compound polymer (A) are properties expressed as a result of the interaction with other molecules. Therefore, the content of T1 sites and the ratio of alkoxy group-containing T1 sites to the total T1 sites can be indicators of the silane compound polymer (A) that is liquid at room temperature and has thermosetting properties, similar to the above-mentioned alkoxy group residue ratio.

[0088] The amount of T1 sites is preferably 2.5 to 25 mol%, more preferably 2.5 to 15 mol%, based on the total amount of T1 sites, T2 sites, and T3 sites. The ratio of alkoxy group-containing T1 sites to the total T1 sites is preferably 5 to 55 mol%, more preferably 5 to 50%, in all T1 sites. The ratio of alkoxy group-containing T1 sites to the total T1 sites can be calculated according to the method described in the examples.

Examples

[0089] Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

[0090] 〔Example 1〕 14.46 g (72.9 mmol) of phenyltrimethoxysilane was charged into a 300 ml eggplant-shaped flask. Then, while stirring this, an aqueous solution in which 0.0188 g of 35% by mass hydrochloric acid (HCl: 0.180 mmol, 0.248 mol% with respect to phenyltrimethoxysilane) was dissolved in 2.62 g (145 mmol) of distilled water was added, and the whole volume was stirred at 24°C for 1 hour. Then, 3.61 g of propyl acetate and 0.0109 g of 28% aqueous ammonia solution (NH3: 0.179 mmol, 0.99 equivalent with respect to HCl) were added and stirred for 2 hours. To the reaction solution, 50 g of propyl acetate and 100 g of water were added for liquid separation treatment, and the organic phase containing the reaction product was separated. Magnesium sulfate was added to this organic phase for drying treatment. After filtering off and removing magnesium sulfate, the organic phase was concentrated with an evaporator, and then the obtained concentrate was vacuum dried to obtain a silane compound polymer.

[0091] [Examples 2 to 4, Comparative Examples 1 to 2] A silane compound polymer was obtained in the same manner as in Example 1, except that the conditions described in Table 1 were changed.

[0092] [Table 1]

[0093] For the silane compound polymers obtained in Examples 1 to 4 and Comparative Examples 1 to 2, the following measurements and tests were conducted respectively. The results are shown in Table 2.

[0094] [Viscosity measurement] In Examples 1 and 2 and Comparative Example 2, a cone plate with a cone radius of 12.5 mm and a cone angle of 0.5° was used with a rheometer (device name "MCR301", manufactured by Anton Paar), and the viscosity was measured at 25°C for 2.2 s -1 of the viscosity. In Example 3, a parallel plate with a radius of 12.5 mm was used, and the viscosity was measured at 25°C at 2.0 rad / s.

[0095] [Thermosetting test] Using an automatic curing time measuring device "Madoka" (manufactured by Cyber Corporation), the curing time was measured under the following conditions. 0.20 mL of the sample was placed on a stainless steel plate heated to 225°C and stirred. Since the stirring torque increased with time, the time (seconds) until it reached 0.049 N·cm was measured. Based on this time, the thermosetting property of the silane compound polymer was evaluated according to the following criteria. Note that since the silane compound polymer obtained in Example 4 was a viscous liquid, as a reference experiment, a thermosetting test was conducted using a sample diluted to a solid content concentration of 90% by weight with a mixed solvent [butyldiglycol acetate:tripropylene glycol monobutyl ether (4:6)]. 〇: 1000 seconds or less △: More than 1000 seconds and 1500 seconds or less ×: Over 1500 seconds The stirring conditions are as follows. · Rotation speed of the stirring blade: 300 rpm · Revolution speed of the stirring blade: 120 rpm · Gap (distance between the heating plate and the stirring blade): 0.2 mm

[0096] 〔 1 1H-NMR measurement〕 Apparatus name: AV-500 manufactured by Bruker BioSpin 1 1H-NMR resonance frequency: 500 MHz Probe: 5 mmφ solution probe Measurement temperature: Room temperature (25 °C) Repetition time: 1 s Number of integrations: 16 times

[0097] 〈 1 1H-NMR sample preparation method〉 Concentration of the silane compound polymer: 3% Measurement solvent: Acetone-d6 Internal standard: TMS

[0098] 〔Alkoxy group residual ratio〕 1 Based on the 1H-NMR measurement results, the ratio of the alkoxy group to the phenyl group was determined, and the alkoxy group residual ratio of the silane compound polymer was calculated.

[0099] 〔 29 29Si-NMR measurement〕 Apparatus name: AV-500 manufactured by Bruker BioSpin 29 29Si-NMR resonance frequency: 99.352 MHz Probe: 5 mmφ solution probe Measurement temperature: Room temperature (25 °C) Sample rotation speed: 20 kHz Measurement method: Inverse gated decoupling method 29 29Si flip angle: 90° 29 29Si 90° pulse width: 8.0 μs Repeating time: 5 s Number of integrations: 9200 times Observation width: 30 kHz

[0100] 〈 29 Si-NMR Sample Preparation Method〉 For shortening the relaxation time, Fe(acac)3 was added as a relaxation reagent and measured. Concentration of silane compound polymer: 15% Concentration of Fe(acac)3: 0.6% Measurement solvent: acetone-d6 Internal standard: TMS

[0101] 〈Waveform Processing and Analysis〉 For each peak of the spectrum after Fourier transform, the chemical shift was determined based on the position of the peak top and integration was performed.

[0102] Note that the signal derived from the T1 site is observed in the region of -65.0 to -60.0 ppm, the signal derived from the T2 site is observed in the region of -74.0 to -65.0 ppm, and the signal derived from the T3 site is observed in the region of -83.0 to -74.0 ppm.

[0103] 〔Ratio of T1 sites containing alkoxy groups to the total T1 sites〕 29 When measuring Si-NMR, the signal derived from the T1 site having one or two alkoxy groups is observed in the region of -63.3 to -62.7 ppm. Therefore, based on the integral value of this region, the ratio of T1 sites containing alkoxy groups to the total T1 sites (T1(OR) / T1(total)) can be calculated.

[0104] 〔Measurement of Average Molecular Weight〕 The mass average molecular weight (Mw) of the silane compound polymer was measured under the following apparatus and conditions. Apparatus name: HLC-8220GPC, manufactured by Tosoh Corporation Column: A sequential connection of "TSK guard column SuperH-H", "TSK gel SuperHM-H", "TSK gel SuperHM-H", and "TSK gel SuperH2000" Solvent: Tetrahydrofuran Standard substance: Polystyrene Injection volume: 20 μl Measurement temperature: 40 °C Flow rate: 0.6 ml / min Detector: Differential refractometer

[0105]

Table 2

[0106] It can be seen from Table 1 and Table 2 below. By comparing Example 1, 2, and Comparative Example 1, 2, the influence of water in the hydrolysis polycondensation reaction of phenyltrimethoxysilane can be understood. That is, when the amount of water added to the reaction system was too small, a liquid silane compound polymer was obtained, but the silane compound polymer was poor in thermosetting properties (Comparative Example 2). On the other hand, when the amount of water added to the reaction system was too large, a solid silane compound polymer was formed (Comparative Example 1). M H2O / M OR When water in an amount such that the value of becomes 0.46 to 0.86 was used, a silane compound polymer that was liquid at room temperature and had thermosetting properties was formed (Examples 1 and 2).

[0107] By comparing Example 1, 3, and 4, the role of Step PO-II can be understood. In Example 3 and Example 4, the reaction of Step PO-II was carried out by increasing the amount of base added compared to Example 1. As a result, in Example 3 and Example 4, a silane compound polymer with a higher molecular weight than that in Example 1 was formed. Thus, by providing Step PO-II, it is possible to relatively easily prepare silane compound polymers with different molecular weights, from low molecular weight to high molecular weight.

Claims

1. A method for producing a silane compound polymer, comprising a step (step PO) of subjecting an alkoxysilane compound to hydrolysis polycondensation in the presence of water and an acid catalyst, wherein the step PO includes a step (step PO-I) of promoting hydrolysis of the alkoxysilane compound in the presence of water and an acid catalyst, and a step (step PO-II) of adjusting the molecular weight of the silane compound polymer, wherein the reaction conditions of the step PO-I are 0 to 50 °C and 10 minutes to 2 hours, wherein the step PO-II is carried out by adding 0.1 to 20 equivalents of a base to the reaction system with respect to the acid catalyst used in the step PO-I, wherein the reaction conditions of the step PO-II are 20 to 85 °C and 20 minutes to 48 hours, wherein at least one of the alkoxysilane compounds is a trifunctional alkoxysilane compound represented by the following formula (1) 【Number】 [R １ represents an unsubstituted aryl group having 6 to 12 carbon atoms or a substituted aryl group having 6 to 12 carbon atoms. OR represents an alkoxy group. ORs may be the same as or different from each other. 〕 and the amount of the trifunctional alkoxysilane compound represented by the formula (1) is more than 50 mol% and 100 mol% or less with respect to the total amount of the trifunctional alkoxysilane compounds, and the molar ratio M of water to alkoxy groups derived from the following formula (F1) is 0.46 to 0.

86. A method for producing a silane compound polymer.

2. 【Number 1】 〔M Ｈ２Ｏ is the number of moles of water added into the reaction system, and M ＯＲ is the total number of moles of alkoxy groups in the alkoxysilane compound.〕 The method for producing a silane compound polymer according to claim 1, wherein the amount of the trifunctional alkoxysilane compound is 80 to 100 mol% in the whole alkoxysilane compound.

3. The method for producing a silane compound polymer according to claim 1 or 2, wherein at least the step PO-II is carried out under stirring conditions.

4. The method for producing a silane compound polymer according to any one of claims 1 to 3, wherein at least the step PO-II is carried out in the presence of an organic solvent.

5. The method for producing a silane compound polymer according to any one of claims 1 to 4, wherein at least the step PO-II is carried out in an open system.

6. The method for producing a silane compound polymer according to any one of claims 1 to 5, wherein the silane compound polymer is liquid at room temperature and has thermosetting properties.

7. The method for producing a silane compound polymer according to claim 6, wherein the silane compound polymer has an alkoxy group residual rate of 2.5 to 25%.

8. The method for producing a silane compound polymer according to claim 6 or 7, wherein the silane compound polymer has a mass average molecular weight (Mw) of 500 to 10,000. ​

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