Method for producing silane compound polymer

Abstract

To provide a method capable of efficiently producing a silane compound polymer having an unsubstituted alkyl group or an alkyl 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 alkyl group having 1 to 10 carbon atoms or an alkyl group having 1 to 10 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, composite optical elements, and optical integrated circuits. In recent years, optical elements that emit blue light or white light with a shorter peak wavelength of emission have been developed and widely used. The high brightness of such light-emitting elements with a short peak wavelength of 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 elements for a long time, resulting in a decrease in adhesive strength. To solve this problem, Patent Documents 1 to 3 propose compositions for fixing optical elements mainly composed of polysilsesquioxane compounds.

[0005] In particular, polysilsesquioxane compounds containing many alkyl groups tend to have a lower refractive index than polysilsesquioxane compounds containing many aryl groups. For this reason, when a fixing material with a low refractive index is required to improve the light extraction efficiency, a polysilsesquioxane compound containing many alkyl 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 the 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, from the viewpoint of reducing environmental impact and the like, solvent-free curable compositions have been desired. For this reason, various studies have been conducted to synthesize a polysilsesquioxane compound that is liquid at room temperature.

[0007] For example, Patent Document 4 describes a method for producing a polysilsesquioxane liquid including hydrolyzing and polycondensing a mixture 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 mainly composed of a polysilsesquioxane having a specific repeating unit. In the production example 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).

Prior Art Documents

Patent Documents

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-359933 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-263869 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-328231 [Patent Document 4] Japanese Patent Application Laid-Open No. 2013-253223 [Patent Document 5] Japanese Patent Application Laid-Open No. 2016-98245 [Patent Document 6] WO2017 / 122762 [Summary of the Invention] [Problems to be Solved by the Invention]

[0011] 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, even when the reaction conditions described in these documents are used, a silane compound polymer that is liquid at room temperature may not be obtained. In addition, only silane compounds with poor thermosetting properties can be obtained even if they are liquid, 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 provides a method capable of efficiently producing a silane compound polymer having an unsubstituted alkyl group or an alkyl group having a substituent, which is liquid at room temperature (25 ° C, the same hereinafter) and has thermosetting properties. In the present invention, "liquid at room temperature" means having fluidity at 25 ° C. In addition, "thermosetting" means the property of curing only by heating even in the absence of a curing catalyst. [Means for Solving the Problems]

[0012] In order to solve the above problems, the present inventors have intensively studied the hydrolysis polycondensation reaction of alkoxysilane compounds. As a result, when hydrolyzing and polycondensing an alkoxysilane compound in the presence of water and an acid catalyst, it was found that by adjusting the amount of water added, a silane compound polymer that is liquid at room temperature and has thermosetting properties can be obtained, and the present invention has been completed.

[0013] Thus, according to the present invention, there is provided a method for producing a silane compound polymer as described in the following [1] to

[12] .

[0014] 〔1〕A method for producing a silane compound polymer having a step (step PO) of hydrolyzing and 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)

[0015]

Chemical formula

[0016] 〔R 1 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.〕 It is a trifunctional alkoxysilane compound represented by the formula (1), the amount of the trifunctional alkoxysilane compound represented by the formula (1) is 50 to 100 mol% based on 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, characterized in that.

[0017]

Number

[0018] 〔M H2O is the number of moles of water added to the reaction system, M ORis 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 total 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 (step PO-I) in the presence of water and an acid catalyst, 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 performed 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. 〔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. 〔7〕The method for producing a silane compound polymer according to any one of 〔3〕 to 〔6〕, wherein at least the step PO-II is performed under stirring conditions. 〔8〕The method for producing a silane compound polymer according to any one of 〔3〕 to 〔7〕, wherein at least the step PO-II is performed in the presence of an organic solvent. 〔9〕The method for producing a silane compound polymer according to any one of 〔3〕 to 〔8〕, wherein at least the step PO-II is performed in an open system. 〔10〕The method for producing a 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. 〔11〕The method for producing a silane compound polymer according to 〔10〕, wherein the silane compound polymer has an alkoxy group residual rate of 2.5 to 25%. The method for producing a silane compound polymer according to

[10] or

[11] , wherein the silane compound polymer has a mass average molecular weight (Mw) of 500 to 20,000.

Advantages of the Invention

[0019] 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

[0020] The method for producing a silane compound polymer of the present invention is a method for producing 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 of the alkoxysilane compounds is a trifunctional alkoxysilane compound represented by the formula (1), and the molar ratio M of water to alkoxy groups derived from the formula (F1) is 0.46 to 0.86.

[0021] 〔Alkoxysilane compound〕 In the method for producing a 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 trimethylmethoxysilane, difunctional alkoxysilane compounds such as dimethyldimethoxysilane, trifunctional alkoxysilane compounds such as methyltrimethoxysilane, and tetrafunctional alkoxysilane compounds such as tetramethoxysilane. Among these, in the method for producing a silane compound polymer of the present invention, as at least one of the alkoxysilane compounds, a trifunctional alkoxysilane compound represented by the following formula (1) is used.

[0022]

Chemical formula

[0023] In formula (1), R 1represents 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. The ORs may be the same as or different from each other.

[0024] In the method for producing the 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 the formula (1), a silane compound polymer that gives a cured product having a relatively low refractive index can be obtained.

[0025] R 1 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 methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, and the like.

[0026] R 1 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. This number of carbon atoms means the number of carbon atoms in the part excluding the substituent (alkyl group part). Therefore, when R 1 is a "substituted alkyl group having 1 to 10 carbon atoms", the number of carbon atoms of R 1 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 for the "unsubstituted alkyl group having 1 to 10 carbon atoms".

[0027] 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 "alkyl group having 1 to 10 carbon atoms and having a substituent" include halogen atoms such as fluorine atom, chlorine atom, and bromine atom; aryl groups such as phenyl group; and the like.

[0028] Among these, R 1 is preferably an unsubstituted alkyl group having 1 to 10 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 methyl 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 methyltrialkoxysilane as a monomer. However, according to the method for producing a silane compound polymer of the present invention, even when methyltrialkoxysilane is used as a monomer, a silane compound polymer that is liquid at room temperature and has thermosetting properties can be efficiently produced.

[0029] 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.

[0030] Specific examples of the trifunctional alkoxysilane compound represented by the formula (1) 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.

[0031] In the method for producing a silane compound polymer of the present invention, the amount of the trifunctional silane compound represented by the formula (1) used is 50 to 100 mol% based on the total amount of the trifunctional alkoxysilane compounds. By using the trifunctional silane compound represented by the formula (1) in an amount of 50 to 100 mol% based on the total amount of the trifunctional alkoxysilane compounds, a silane compound polymer capable of providing a cured product having a relatively low 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 the formula (1) used 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 provides a cured product with a lower refractive index is required, the amount of the trifunctional silane compound represented by the 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.

[0032] 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 the formula (1), examples of such a trifunctional silane compound include a trifunctional silane compound represented by the following formula (2).

[0033]

Chemical formula

[0034] In the formula (2), R 2 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.

[0035] R 2 The number of carbon atoms 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, a 2-naphthyl group, and the like.

[0036] R2 The number of carbon atoms of the "aryl group having 6 to 12 carbon atoms and having a substituent" represented by is preferably 6. Note that this number of carbon atoms means the number of carbon atoms of the part excluding the substituent (the aryl group part). Therefore, R 2 When is the "aryl group having 6 to 12 carbon atoms and having a substituent", the number of carbon atoms of R 2 may exceed 12. Examples of the aryl group of the "aryl group having 6 to 12 carbon atoms and having a substituent" include the same ones as those shown as the "aryl group having 6 to 12 carbon atoms and having no substituent".

[0037] The number of atoms of the substituent (excluding the number of hydrogen atoms) of the "aryl group having 6 to 12 carbon atoms and having 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 and having 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.

[0038] 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 methoxy group, ethoxy group, propoxy group and the like.

[0039] Specific examples of the trifunctional alkoxysilane compound represented by the formula (2) include aryltrialkoxysilane compounds such as phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane; Substituted aryltrialkoxysilane compounds such as 4-methoxyphenyltrimethoxysilane, 4-methoxyphenyltriethoxysilane, 4-methoxyphenyltripropoxysilane; and the like. These trifunctional alkoxysilane compounds can be used alone or in combination of two or more.

[0040] 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 easier to obtain a silane compound polymer that is liquid at room temperature and has thermosetting properties.

[0041] 〔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.

[0042]

Number

[0043] 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 mol of water is added to 1 mol of methyltrialkoxysilane, the value of the molar ratio M is 1 / 3 (0.33).

[0044] 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.

[0045] 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 resulting silane compound polymer. That is, as will be described later, in the silane compound polymer, it is considered that the alkoxy groups contribute to the liquefaction of the silane compound polymer and the hydroxy groups contribute to the thermosetting properties 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.

[0046] 〔Acid catalyst〕 In the method for producing a silane compound polymer of the present invention, an acid catalyst is used as a 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.

[0047] 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.

[0048] 〔Step of hydrolytic polycondensation of alkoxysilane compound (Step PO)〕 The method for producing the silane compound polymer of the present invention has a step (step PO) of subjecting an alkoxysilane compound to hydrolysis polycondensation in the presence of water and an acid catalyst.

[0049] 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.

[0050] As long as the requirement regarding the "molar ratio M of water to alkoxy group" is satisfied, the reaction conditions of step PO are not particularly limited. The reaction temperature of step PO is usually 0 to 85°C, preferably 15 to 75°C. The reaction time of step PO is usually from 30 minutes to 50 hours, preferably 1 to 24 hours.

[0051] 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 a target molecular weight can be efficiently produced, step PO preferably includes a step of promoting hydrolysis of an alkoxysilane compound (step PO-I) and a step of adjusting the molecular weight of the silane compound polymer (step PO-II) in the presence of water and an acid catalyst.

[0052] Step PO-I is a step of promoting 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 in 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.

[0053] 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 usually 0 to 50°C, preferably 15 to 35°C. The reaction time of step PO-I is usually from 10 minutes to 2 hours, preferably 15 to 90 minutes.

[0054] The water added for hydrolysis of the alkoxysilane compound is preferably sufficiently 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 1H-NMR of the reaction product and comparing the amount of "Si-R" with the amount of "Si-OR". 1 Measure 1H-NMR and 1 It can be estimated by comparing the amount of "Si-R" with the amount of "Si-OR". In addition, in step PO-I, not only the hydrolysis reaction of the alkoxysilane compound but also the polycondensation reaction of the hydrolysis reaction product may proceed.

[0055] 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.

[0056] In order to adjust the molecular weight of the silane compound polymer, when performing Step PO-II, it is preferable to add a base to the reaction system as necessary. By adding a relatively large amount of base, performing Step PO-II at a relatively high temperature, or lengthening 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, performing Step PO-II at a relatively low temperature, 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.

[0057] When adding a base to the reaction system when performing 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.

[0058] 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.

[0059] The reaction conditions of Step PO-II are not particularly limited. The reaction temperature of Step PO-II is generally 20 to 85°C, preferably 24 to 75°C. The reaction time of Step PO-II is generally from 20 minutes to 48 hours, preferably 1 to 24 hours.

[0060] 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, paragraph (0020) of Patent Document 4 describes that "a mixture composed 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, a mixture composed of a trifunctional silicon alkoxide, water, and an acid catalyst is stirred at 20°C for 3 hours in a sealed container and then aged (left standing) at 60°C for 24 hours to produce a silane compound polymer.

[0061] Step PO-II allows the polycondensation reaction to proceed sufficiently in the same manner as the aging step, but, 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 step suitable for the polycondensation reaction after adding a sufficient amount of water (3 equivalents of water with respect to the trifunctional silicon alkoxide) as in the examples of Patent Document 4 and substituting almost all alkoxy groups with hydroxy groups. 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, in order to efficiently carry out the polycondensation reaction of this reaction product and obtain a silane compound polymer having the target molecular weight, it is preferable to stir the inside of the reaction system.

[0062] 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 inside of 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.

[0063] 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 the 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, an organic solvent is preferably used in an amount of 0.05 to 3 times, more preferably 0.1 to 1.5 times, based on volume, with respect to the alkoxysilane compound used in step PO-I.

[0064] 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 likely to be released outside the reaction system, so that it is possible to avoid the inhibition of the polycondensation reaction 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 its surrounding system are not completely blocked and are in a state where molecular movement is possible between them.

[0065] [Step of purifying the silane compound polymer (Step PU)] In the method for producing the silane compound polymer of the present invention, after Step PO, it is preferable to carry out a step of purifying the silane compound polymer (Step PU). 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.

[0066] Examples of Step PU include a purification step by a solvent extraction method. Examples of the purification step 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, if necessary, to the reaction mixture obtained in Step PO, stirring the same, and then allowing it to stand to separate into an organic phase and an aqueous phase (Step PU-II) A step of separating the organic phase formed in Step PU-I and washing the organic phase with water, if necessary (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

[0067] In step PU-I, if 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 is separated into an organic phase and an aqueous phase. The amount of the solvent to be added and the type of the organic solvent are not particularly limited as long as the reaction mixture obtained in step PO is separated into an organic phase and an aqueous phase.

[0068] 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.

[0069] In step PU-III, the organic phase is dried according to a conventional method such as addition of magnesium sulfate.

[0070] 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.

[0071] 〔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 method for producing a silane compound polymer of the present invention may be referred to as "silane compound polymer (A)".

[0072] 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.

[0073] In this specification, the "viscosity at 25°C" refers to the viscosity with respect to a shear rate of 2.2 s -1 using a cone plate with a cone radius (radius of the cone bottom surface) of 12.5 mm and a cone angle of 0.5 degrees. However, when the measurement exceeds 50 Pa·s, 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.

[0074] When the silane compound polymer (A) is subjected to the thermosetting test described in the examples, those with 1500 seconds or less are preferred, and those with 1000 seconds or less are more preferred. The silane compound polymer (A) with a thermosetting test result of 1500 seconds or less is more suitable as a curable component of a curable composition containing no 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 100 to 1500 seconds are preferred.

[0075] The residual ratio of alkoxy groups in the silane compound polymer (A) is preferably 2.5 to 25%, and more preferably 3.0 to 20%. The residual ratio of alkoxy groups in the silane compound polymer (A) represents the degree to which the alkoxy groups contained in the alkoxysilane compound used as a monomer remain in the silane compound polymer (A). The silane compound polymer (A) with a residual ratio of alkoxy groups of 2.5% or more tends to become liquid at room temperature. The silane compound polymer (A) with a residual ratio of alkoxy groups of 25% or less tends to have sufficient thermosetting properties.

[0076] The alkoxy group residual ratio can be calculated by measuring the 1 1 1H-NMR of the silane compound polymer (A). For example, when the silane compound polymer (A) is produced using methyltriethoxysilane, the 1 1 1H-NMR of the silane compound polymer (A) is measured, and the ratio of the methyl group to the ethoxy group is determined based on the peak area ratio, whereby the alkoxy group residual ratio of the silane compound polymer (A) can be calculated. 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, etc., the NMR of the silane compound polymer (A) in a solution state can be measured using these solvents.

[0077] As described above, the method for producing a 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 the alkoxysilane compound to hydrolysis polycondensation under such conditions, the silane compound polymer (A) having a well-balanced alkoxy group contributing to the liquefaction of the silane compound polymer and a hydroxy group contributing to the thermosetting property, being liquid at room temperature, and having thermosetting properties can be produced.

[0078] The mass average molecular weight (Mw) of the silane compound polymer (A) is preferably 500 to 20,000, more preferably 600 to 10,000, and still more preferably 700 to 5,000. The molecular weight distribution (Mw / Mn) of the silane compound polymer (A) is not particularly limited, but is usually 1.00 to 10.00, preferably 1.10 to 6.00, and more preferably 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.

[0079] As described above, the silane compound polymer (A) having the target 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.

[0080] The silane compound polymer (A) has a repeating unit represented by the following formula (3).

[0081]

Chemical formula

[0082] In formula (3), R 1 represents the same meaning as described above. O 1 / 2 represents that the oxygen atom is shared with the adjacent repeating unit.

[0083] As shown by formula (3), the silane compound polymer (A) generally has a partial structure collectively referred to as a T site, in which three oxygen atoms are bonded to a silicon atom and one other group (a group represented by R 1 is bonded). Examples of the T site contained in the silane compound polymer (A) include those represented by the following formulas (4) to (6).

[0084]

Chemical formula

[0085] 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. X 1 ~X 3Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and the like. In the above formulas (4) to (6), * is bonded to a Si atom.

[0086] 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 as described in Patent Document 6. 29 It can be determined by measuring the Si-NMR. As shown in the 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 portion of the silane compound polymer (A) and is an important site when interacting with other molecules. The state (liquid or solid) and thermosetting property of the silane compound polymer (A) are properties expressed as a result of the interaction with other molecules. Therefore, the content of the T1 site and the ratio of the alkoxy group-containing T1 site to the total T1 sites can be an index of the silane compound polymer (A) that is liquid at room temperature and has thermosetting properties, similar to the above-mentioned alkoxy group residual ratio.

[0087] The amount of the T1 site is preferably 2.5 to 25 mol%, more preferably 2.5 to 15 mol%, based on the total amount of the T1 site, T2 site, and T3 site. The ratio of the alkoxy group-containing T1 site to the total T1 sites is preferably 5 to 55 mol%, more preferably 5 to 50%, in all the T1 sites. The ratio of the alkoxy group-containing T1 site to the total T1 sites can be calculated according to the method described in the examples.

Examples

[0088] 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 at all.

[0089] [Example 1] After charging 47.41 g (266 mmol) of methyltriethoxysilane into a 300 ml eggplant-shaped flask, while stirring this, an aqueous solution in which 0.0693 g of 35% by mass hydrochloric acid (HCl: 0.665 mmol, 0.250 mol% with respect to methyltriethoxysilane) was dissolved in 9.576 g (531 mmol) of distilled water was added, and the whole volume was stirred at 30 °C for 1 hour. The system was heated to 70 °C, and 11.9 g of propyl acetate and 0.040 g of 28% aqueous ammonia solution (NH3: 0.658 mmol, 0.99 equivalent with respect to HCl) were added thereto, and the mixture was stirred for 2 hours. After allowing the reaction solution to cool to room temperature (25 °C), 100 g of propyl acetate and 200 g of water were added thereto, and liquid separation treatment was performed to separate and collect the organic phase containing the reaction product. 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.

[0090] [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.

[0091] [Table 1]

[0092] For the silane compound polymers obtained in Examples 1 to 4 and Comparative Examples 1 to 2, the following measurements and tests were performed respectively. The results are shown in Table 2.

[0093] [Viscosity Measurement] In Examples 1 and 2 and Comparative Example 2, using a cone plate with a cone radius of 12.5 mm and a cone angle of 0.5° in a rheometer (device name "MCR301", manufactured by Anton Paar), the viscosity at 25 °C for 2.2 s -1 was measured. In Examples 3 and 4, using a parallel plate with a radius of 12.5 mm, the viscosity at 25 °C and 2.0 rad / s was measured.

[0094] 〔Thermosetting test〕 Using the automatic hardening time measuring device "Madoka" (manufactured by Cyber Co., Ltd.), the hardening time was measured under the following conditions. 0.20 mL of the sample was placed on a stainless steel plate heated to 170 °C and stirred. Since the stirring torque increased over time, the time (seconds) until it reached 0.049 N·cm was measured. Based on this time, the thermosetting properties of the silane compound polymer were evaluated according to the following criteria. Since the silane compound polymer obtained in Comparative Example 1 was solid, as a reference experiment, a sample diluted to a solid content concentration of 90 wt% with a mixed solvent [butyl diglycol acetate: tripropylene glycol monobutyl ether (4:6)] was used to conduct a thermosetting test. 〇: 1000 seconds or less △: More than 1000 seconds and 1500 seconds or less ×: More than 1500 seconds The stirring conditions are as follows. · Rotation speed of the stirring blade: 200 rpm · Revolution speed of the stirring blade: 80 rpm · Gap (distance between the heating plate and the stirring blade): 0.2 mm

[0095] 〔 1 1H-NMR measurement〕 Device 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

[0096] 〈 1 1H-NMR sample preparation method〉 Silane compound polymer concentration: 3% Measurement solvent: Acetone-d6 Internal standard: TMS

[0097] 〔Residual ratio of alkoxy groups〕 1 Based on the 1H-NMR measurement results, the ratio of the alkoxy group to the methyl group was determined, and the residual rate of the alkoxy group in the silane compound polymer was calculated.

[0098] 〔 29 Si-NMR Measurement〕 Apparatus name: AV-500 manufactured by Bruker BioSpin 29 Si-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 Si flip angle: 90° 29 Si 90° pulse width: 8.0 μs Repetition time: 5 s Number of integrations: 9200 times Observation width: 30 kHz

[0099] 〈 29 Si-NMR Sample Preparation Method〉 To shorten the relaxation time, Fe(acac)3 was added as a relaxation reagent for measurement. Silane compound polymer concentration: 15% Fe(acac)3 concentration: 0.6% Measurement solvent: Acetone-d6 Internal standard: TMS

[0100] 〈Waveform Processing and Analysis〉 For each peak in the spectrum after Fourier transform, the chemical shift was determined based on the position of the peak top, and integration was performed.

[0101] Note that the signal derived from the T1 site was observed in the region of -52.0 to -45.0 ppm, the signal derived from the T2 site was observed in the region of -60.7 to -52.0 ppm, and the signal derived from the T3 site was observed in the region of -71.5 to -60.7 ppm.

[0102] [Ratio of T1 sites containing alkoxy groups to the entire T1 sites] 29 When Si-NMR is measured, signals derived from T1 sites having one or two alkoxy groups are observed in the region of -52.0 to -50.0 ppm. Therefore, based on the integral value of this region, the ratio of T1 sites containing alkoxy groups to the entire T1 sites (T1(OR) / T1(total)) can be calculated.

[0103] [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 series connected in sequence 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

[0104] [Table 2]

[0105] It can be seen from Table 1 and Table 2 that the following can be understood. By comparing Examples 1 and 2 with Comparative Examples 1 and 2, the influence of water in the hydrolysis polycondensation reaction of methyltriethoxysilane can be known. 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 inferior 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 / MOR When an amount of water was used such that the value of OR was from 0.46 to 0.86, a silane compound polymer that was liquid at room temperature and had thermosetting properties was formed (Examples 1 and 2).

[0106] By comparing Examples 1, 3, and 4, the role of Step PO-II can be understood. In Example 3, while increasing the addition amount of the acid catalyst compared to Example 1 and shortening the reaction time of Step PO-I, the reaction of Step PO-II was carried out for a long time. As a result, in Example 3, a silane compound polymer with a higher molecular weight than that in Example 1 was formed. Also, in Example 4, after carrying out Step PO-I under conditions almost the same as those in Example 1, the addition amount of the base was increased and the reaction of Step PO-II was carried out for a long time. As a result, a silane compound polymer with an even higher molecular weight than that in Example 3 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 ones to high-molecular-weight ones.

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 alkyl group having 1 to 10 carbon atoms or a substituted alkyl group having 1 to 10 carbon atoms. OR represents an alkoxy group. ORs may be the same as or different from each other. ] and is a trifunctional alkoxysilane compound represented by the formula (1), wherein the amount of the trifunctional alkoxysilane compound represented by the formula (1) is 50 to 100 mol% based on the total amount of the trifunctional alkoxysilane compounds, and a method for producing a silane compound polymer, characterized in that the molar ratio M of water to alkoxy groups derived from the following formula (F1) is 0.46 to 0.

86. 【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.

2. 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 compounds.

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 ratio 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 20,000.

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