Silicon-isocyanate compound-containing composition and method for producing same

Abstract

Provided is a method for producing a silicon isocyanate compound-containing a composition in which the purity of a silicon isocyanate compound as a monomer is high, at an industrial scale and at low cost. This silicon isocyanate compound-containing composition is produced by reacting a halogenated silicon compound with a cyanic acid salt or an isocyanic acid salt in the presence of a solvent and an alkylene glycol compound, by a method having steps (A) to (D): (A) a step for mixing the cyanic acid salt or isocyanic acid salt, an azeotropic solvent, the alkylene glycol compound, and the solvent together to generate a liquid; (B) a step for heating the liquid to remove water and the azeotropic solvent; (C) a step for adding the halogenated silicon compound to the liquid to generate the silicon isocyanate compound; and (D) a step for heating the liquid to distill and collect the silicon isocyanate compound.

Description

[Technical field]

[0001] The present invention relates to a method for producing a silicon isocyanate compound-containing composition, and more specifically, to a method for producing a silicon isocyanate compound-containing composition, which is characterized by carrying out a dehydration step using an azeotropic solvent. [Background technology]

[0002] Silicon isocyanate compounds are used as polymer modifiers because they react easily with compounds containing active hydrogen in the molecule, such as alcohols, primary amines, secondary amines, and carboxylic acids. Silicon isocyanate compounds can also be easily introduced as a component of a polymer, and the properties of silicon can be added to industrial materials. Furthermore, silicon isocyanate compounds react quickly with water, and therefore can react with moisture in the air or adsorbed water present on the surfaces of glass, ceramics, metals, and the like, to form a silicon oxide film with high adhesion.

[0003] Known methods for producing silicon isocyanate compounds include a method in which a halogenated silane compound having a Si-X (X represents a halogen) bond is reacted with a cyanate or an isocyanate in the presence of an alkylamine, a nitroalkane, or a crown ether in the presence of a solvent (Patent Document 1), and a method in which a halogenated silane compound is reacted with a cyanate or an isocyanate in the presence of an alkylene glycol compound (Patent Document 2).

[0004] Other known methods include a production method in which hexaorganodisilazane is reacted with carbon dioxide gas in the presence of iron chloride (Patent Document 3), a production method in which trichlorosilane is reacted with an alkali cyanate in an organic solvent containing a small amount of acetonitrile (Patent Document 4), and a production method in which organotin isocyanates are reacted with an organosilicon compound having an active halogen atom (Patent Document 5).

[0005] On the other hand, it is known that silicon isocyanate compounds react with water to form dimer compounds or oligomer compounds (for example, Patent Document 6), and if water is mixed into the reaction system, it leads to a decrease in the purity of the silicon isocyanate compound (monomer). Therefore, in order to obtain a high-purity silicon isocyanate compound monomer, it is necessary to thoroughly remove water from the raw material compound.

[0006] In the examples of Patent Document 2, a silicon isocyanate compound is produced using a dehydrated cyanate or isocyanate. However, unless other compounds used in the reaction, such as the solvent or alkylene glycol, are dehydrated, the halogenated silane compound will react with the contained water before reacting with the cyanate or isocyanate.

[0007] As a method for dehydrating cyanate or isocyanate, a method of dehydrating by heating over an open flame under reduced pressure is known, but this method requires two steps, a heating and dehydration step and a reaction step. In addition, when considering implementation at an industrial level, it is difficult to produce the cyanate or isocyanate by a process of heating a production vessel over an open flame. Furthermore, it is difficult to obtain a cyanate or isocyanate that is uniformly dehydrated.

[0008] Furthermore, in the method of Patent Document 2, when the reaction accelerator and the solvent are heated by direct flame, it is difficult to dehydrate them while avoiding thermal decomposition.

[0009] Other dehydration methods include those using solid adsorbents such as molecular sieves, activated clay, and silica gel. However, a solution consisting of a cyanate or isocyanate, a reaction promoter, and a solvent is in a slurry state, and it is difficult to separate only the solid adsorbent from this mixed solution. If the solid adsorbent is reacted with a halogenated silane compound while remaining in the state, it will react with the water contained in the solid adsorbent, leading to a decrease in yield and / or purity.

[0010] In order to obtain higher quality silicon oxide films, there is a demand for silicon isocyanate compound-containing compositions having a high monomer purity, and there is a demand for the development of new production methods for producing such silicon isocyanate compound-containing compositions. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 56-26895 [Patent Document 2] Japanese Patent Application Publication No. 167785 / 1985 [Patent Document 3] Japanese Patent Application Publication No. 54-119419 [Patent Document 4] Japanese Patent Application Publication No. 7-188257 [Patent Document 5] Japanese Patent Application Publication No. 55-102589 [Patent Document 6] JP 2000-247982 A Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made in view of the above-mentioned background art, and an object of the present invention is to provide a method for producing a silicon isocyanate compound-containing composition having a high purity of the silicon isocyanate compound monomer, which can be carried out on an industrial level and can produce a silicon isocyanate compound-containing composition at low cost. [Means for solving the problem]

[0013] The present inventors have conducted intensive research to solve the above-mentioned problems, and as a result have found that in a method for producing a silicon isocyanate compound-containing composition by reacting a halogenated silane compound with a cyanate or isocyanate salt in the presence of an alkylene glycol compound, the problem of a decrease in purity of the silicon isocyanate compound monomer due to the inclusion of water, which has been an issue in conventional production methods, can be resolved by adding an azeotropic solvent to a liquid containing the cyanate or isocyanate salt and the alkylene glycol compound before adding the halogenated silane compound, and carrying out a dehydration step by azeotroping the azeotropic solvent with water, thereby completing the present invention.

[0014] That is, the present invention provides a method for producing a silicon isocyanate compound-containing composition, which comprises reacting a halogenated silicon compound with a cyanate or isocyanate in the presence of a solvent and an alkylene glycol compound to produce a silicon isocyanate compound, the method comprising the following steps (A) to (D):

[0015] (A) a step of mixing the cyanate or isocyanate, an azeotropic solvent, the alkylene glycol compound, and the solvent to generate a liquid; (B) heating the liquid to remove water and the azeotropic solvent. (C) adding the halogenated silicon compound to the liquid to produce the silicon isocyanate compound. (D) a step of heating the liquid to distill off and recover the silicon isocyanate compound.

[0016] The present invention also provides a silicon isocyanate compound-containing composition, which is characterized by containing 80 mass % or more of a silicon isocyanate compound.

[0017] The present invention also provides a method for producing a silicon oxide or a silicon oxide film, which comprises using, as a silicon precursor, the silicon isocyanato compound-containing composition produced by the above-mentioned method for producing a silicon isocyanato compound-containing composition. Effect of the Invention

[0018] According to the present invention, a method for producing a silicon isocyanato compound-containing composition having a high purity of the silicon isocyanato compound monomer can be provided. Specifically, the present invention can provide a silicon isocyanato compound-containing composition having a purity of 80 mass% or more of the silicon isocyanato compound monomer before purification. Furthermore, the method of the present invention can be carried out on an industrial scale, and enables the production of a silicon isocyanate compound-containing composition at low cost. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention will be described below, but the present invention is not limited to the following embodiments and can be practiced in any modified form.

[0020] The method for producing a silicon isocyanate compound-containing composition of the present invention comprises reacting a halogenated silicon compound with a cyanate or isocyanate in the presence of a solvent and an alkylene glycol compound to produce a silicon isocyanate compound.

[0021] <Silicon isocyanate compounds> "Silicon isocyanate compound" refers to any compound in which silicon (Si) and an isocyanate group (-N=C=O) are directly bonded.

[0022] Among silicon isocyanate compounds, those having only one silicon atom in the molecule, that is, monomers of silicon isocyanate compounds, are particularly suitable for production by the production method of the present invention. An example of such a silicon isocyanate compound monomer is represented by the following formula (1).

[0023] R n (OR) m Si(NCO) 4-nーm (1)

[0024] In formula (1), R is an optionally substituted hydrocarbon group, and when a plurality of Rs are present, each R may be different. n and m are each an integer of 0 to 3, and the sum of n and m is an integer of 0 to 3.

[0025] R may be saturated or unsaturated, or may have an aromatic ring. Specific examples of R include a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group, a decyl group, a stearyl group, a behenyl group, a vinyl group (only when m=0), an allyl group, a propargyl group, a phenyl group, a naphthyl group, a benzyl group, an ethoxymethyl group, an ethoxyethyl group, an ethoxypropyl group, a butoxydiethyleneglycoxyethyl group, a pentafluoroethyl group, and a heptafluoropropyl group.

[0026] Among the monomers of the silicon isocyanate compound represented by the above formula (1), the one represented by the following formula (1a) is in demand for various applications such as a precursor of a silicon oxide film, and is particularly suitable for producing a high-purity product by the production method of the present invention.

[0027] R n Si(NCO) 4-n (1a)

[0028] Specific examples of the silicon isocyanato compound monomer produced by the production method of the present invention include tetraisocyanatosilane, methyltriisocyanatosilane, ethyltriisocyanatosilane, dimethyldiisocyanatosilane, diethyldiisocyanatosilane, trimethylisocyanatosilane, triethylisocyanatosilane, etc., which are in demand for a variety of applications such as precursors for silicon oxide films, and are particularly preferred as applications of the present invention, which can produce these with high purity.

[0029] <Halogenated silicon compounds> The silicon halide compound is a raw material for producing a silicon isocyanate compound by reaction with a cyanate or an isocyanate, which will be described later.

[0030] A "halogenated silicon compound" is a compound that contains silicon and a halogen bonded to the silicon. Although not limited thereto, a typical example of the halogenated silicon compound is one represented by the following formula (2):

[0031] R n (OR) m Six 4-nーm (2)

[0032] In formula (2), R is an optionally substituted hydrocarbon group, and when a plurality of Rs are present, each R may be different. X is a halogen. n and m are each an integer of 0 to 3, and the sum of n and m is an integer of 0 to 3.

[0033] R in the formula (2) may be saturated or unsaturated, or may have an aromatic ring. Specific examples of R in the formula (2) are the same as those of R in the formula (1) described above. X in the formula (2) is preferably chlorine (Cl), bromine (Br) or iodine (I), and particularly preferably chlorine or bromine.

[0034] Specific examples of the halogenated silicon compound represented by formula (2) include tetrachlorosilane, methyltrichlorosilane, ethyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, trimethylchlorosilane, triethylchlorosilane, tetrabromosilane, methyltribromosilane, ethyltribromosilane, dimethyldibromosilane, diethyldibromosilane, trimethylbromosilane, triethylbromosilane, and the like.

[0035] <Cyanates / Isocyanates> The cyanate and isocyanate are raw materials for producing a silicon isocyanate compound by reaction with the above-mentioned silicon halide compound.

[0036] Cyanate is M(OCN) m(M is a metal, m is a natural number), and is a salt of cyanic acid (HOC≡N) and a metal. The cyanate in the production method of the present invention is preferably a salt with an alkali metal or an alkaline earth metal. More preferred examples of the alkali metal include lithium (Li), sodium (Na), and potassium (K), and more preferred examples of the alkaline earth metal include magnesium (Mg), calcium (Ca), and barium (Ba).

[0037] Isocyanates are M(NCO) m (M is a metal, m is a natural number), and is a salt of isocyanic acid (HN=C=O) and a metal. Examples of the isocyanate salt in the production method of the present invention include salts with silver (Ag), ammonium, etc.

[0038] It is known that isocyanic acid (HN=C=O) and cyanic acid (HOC≡N) are tautomers, and that salts of silver and ammonium usually exist as isocyanates, while salts of alkali metals and lead usually exist as cyanates. As for the corresponding silicon compounds, most of them are said to take the form of isocyanates of Si-N=C=O.

[0039] Among the cyanates and isocyanates, sodium cyanate, potassium cyanate, and lithium cyanate are particularly preferred from the practical standpoints of availability, reactivity, ease of handling, etc., with sodium cyanate being the most preferred.

[0040] The cyanate or isocyanate is preferably used in an equimolar amount or more relative to the halogen contained in the halogenated silicon compound to be substituted, and it is particularly preferred that the cyanate or isocyanate is used in an excess of 0.1 to 2 equivalents relative to the halogen.

[0041] <Alkylene glycol compounds> The silicon isocyanate compound can be obtained by reacting the above-mentioned silicon halide compound with a cyanate or an isocyanate. In order to increase the reaction yield, the reaction is carried out in the presence of various reaction accelerators. In the present invention, an alkylene glycol compound is used as the reaction accelerator.

[0042] Examples of the alkylene glycol compound in the production method of the present invention include alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, and octylene glycol; halogen-substituted alkylene glycols; polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol; and halogen-substituted polyalkylene glycols.

[0043] Further, ether derivatives and ester derivatives of polyalkylene glycols and their halogen-substituted products are also included as examples of the alkylene glycol-based compound in the production method of the present invention.

[0044] The ether derivative may be a monoether derivative in which only one end of the polyalkylene glycol chain is substituted with a substituent, or a diether derivative in which both ends are substituted with a substituent. The substituent of the ether derivative may be a hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, an oleyl group, a stearyl group, a benzyl group, or a phenyl group; a furfuryl group; a glyceryl group; a residue of a cyclic polyhydric hydroxy compound such as sorbitol or saccharose; or the like. The hydrogen atom in these substituents may be substituted with a halogen.

[0045] The ester derivative may be a monoester derivative in which only one end of the polyalkylene glycol chain is substituted with a substituent, or a diester derivative in which both ends are substituted with a substituent. Examples of the substituent of the ester derivative include a formyl group, an acetyl group, a propionyl group, a butanoyl group, and a benzoyl group. The hydrogen atom in these substituents may be substituted with a halogen.

[0046] A compound in which one end of a polyalkylene glycol chain is substituted with a substituent of the ether derivative described above and the other end is substituted with a substituent of the ester derivative described above can also be used as the alkylene glycol compound in the production method of the present invention.

[0047] These alkylene glycol compounds may be used alone or in combination of two or more depending on the desired reactivity. Among these alkylene glycol compounds, ethylene glycol, polyethylene glycol and various derivatives thereof have particularly good reactivity and are therefore preferred as the reaction accelerator in the present invention. Furthermore, in the present invention, since a high-purity silicon isocyanate compound monomer can be obtained by removing water from the reaction system by azeotropic dehydration, among alkylene glycol compounds, compounds that do not contain active hydrogen in the structure can be preferably used.

[0048] The alkylene glycol compounds described above generally give good results when their structure shows a calculated HLB value of at least 10.5, particularly at least 13.5, when calculated according to the standard method for surfactants.

[0049] The amount of the alkylene glycol compound added is preferably 0.01 parts by mass or more, and more preferably 0.05 parts by mass or more, based on 100 parts by mass of the halogenated silicon compound, and is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less. If the amount is equal to or more than the lower limit, the reaction time can be sufficiently shortened, and the productivity can be easily improved (if the amount is less than 0.01 parts by mass, the time required to complete the reaction can be 5 hours or more). If the amount is equal to or less than the upper limit, the yield can be easily increased (for example, if the amount is more than 20 parts by mass, the reaction rate increases, but the yield can decrease because the silicon compound reacts with the alkylene glycol compound when it has an OH group).

[0050] <Solvent> In the present invention, the above-mentioned cyanic acid or isocyanate, the alkylene glycol compound, and the azeotropic solvent described below are added to a solvent and mixed to generate a liquid. The liquid may be a solution in which each component is dissolved in the solvent, or may be a suspension such as a slurry. After removing water from the liquid by azeotropic dehydration, a halogenated silicon compound is added to the liquid and reacted with heat to obtain a silicon isocyanate compound-containing composition.

[0051] The solvent must be a substance that does not alter the reaction raw materials and reaction products. Examples of such a solvent include organic solvents such as hydrocarbons and halogenated hydrocarbons, etc. Specific examples include n-hexane, cyclohexane, petroleum ether, liquid paraffin, benzene, toluene, xylene, chloroform, trichloroethylene, 1,1,2,2-tetrachloroethane, chlorobenzene, triethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, diisononyl phthalate, and dibutyl phthalate.

[0052] It is preferable to use these solvents in an amount necessary to uniformly dissolve or disperse the cyanate or isocyanate by stirring.

[0053] <Azeotropic solvent> In the present invention, before the reaction, an azeotropic solvent is added to the solvent in addition to the cyanic acid or isocyanate and the alkylene glycol compound.

[0054] In the reaction between cyanic acid or isocyanate and a halogenated silicon compound, if water is present, it will react with the halogenated silicon compound or with the product silicon isocyanate compound to produce dimers or more of silicon isocyanate compounds, leading to a decrease in the purity of the silicon isocyanate compound monomer and a decrease in yield. Water is contained as an impurity in the isocyanic acid or isocyanate, the reaction accelerator (alkylene glycol compound), and the solvent.

[0055] In the present invention, in order to remove the water contained in these, an azeotropic solvent is added to the solvent to carry out azeotropic dehydration. In the present invention, water can be removed sufficiently compared to the method of dehydrating the raw material cyanate or isocyanate in advance, as in Patent Document 2, so that a silicon isocyanate compound-containing composition with high purity of silicon isocyanate compound monomer can be obtained.

[0056] The azeotropic solvent must be one that does not alter the reaction raw materials and reaction products. For example, an organic solvent that does not contain active hydrogen in its chemical structure can be used as the azeotropic solvent.

[0057] The azeotropic solvent is preferably a hydrocarbon, particularly preferably an aromatic hydrocarbon, and specific examples of the compound include benzene, toluene, xylene, and ethylbenzene. The azeotropic solvent may be used alone or in combination of two or more kinds.

[0058] The method for producing a silicon isocyanate compound-containing composition of the present invention comprises the steps (A) to (D) described below.

[0059] [Process (A)] In step (A), the cyanate or isocyanic acid, the azeotropic solvent, the alkylene glycol compound, and the solvent are mixed to generate a liquid. The liquid may be a solution in which each component is dissolved in the solvent, or a suspension such as a slurry.

[0060] In step (A), the order of adding each component is not particularly limited. It is preferable to carry out step (A) while stirring the inside of a reaction vessel so that each component is thoroughly mixed.

[0061] [Process (B)] In step (B), the liquid produced in step (A) is heated to remove water and the azeotropic solvent. By carrying out step (B), water is removed from the liquid, and as a result, during the reaction between the cyanate or isocyanic acid and the halogenated silicon compound, a polymerization reaction caused by the reaction with water can be prevented, and a silicon isocyanate compound-containing composition having a high purity of the silicon isocyanate compound monomer can be obtained.

[0062] In step (B), the conditions for carrying out azeotropic dehydration are not particularly limited, but it is preferable to carry out azeotropic dehydration under normal pressure, and then to carry out further azeotropic dehydration under reduced pressure.

[0063] The liquid temperature in the azeotropic dehydration under normal pressure is preferably 20° C. or higher, more preferably 50° C. or higher, and particularly preferably 100° C. or higher, and is preferably 250° C. or lower, more preferably 230° C. or lower, and particularly preferably 200° C. or lower. When the liquid temperature is within the above range, it is possible to produce a silicon isocyanate compound-containing composition without decreasing the purity and yield of the silicon isocyanate compound monomer.

[0064] The liquid temperature when azeotropic dehydration is further performed under reduced pressure after azeotropic dehydration under normal pressure is preferably 20° C. or higher, more preferably 50° C. or higher, and particularly preferably 100° C. or higher, and is preferably 250° C. or lower, more preferably 230° C. or lower, and particularly preferably 200° C. or lower. The degree of reduced pressure (pressure) is preferably 0.1 kPa or more, more preferably 0.3 kPa or more, and particularly preferably 0.5 kPa or more, and is preferably 101.3 kPa or less, more preferably 90 kPa or less, and particularly preferably 50 kPa or less. When the liquid temperature and the degree of reduced pressure (pressure) are within the above ranges, it is possible to produce a silicon isocyanate compound-containing composition without decreasing the purity and yield of the silicon isocyanate compound monomer.

[0065] [Process (C)] In step (C), the above-mentioned silicon halide compound is added to the liquid from which water and the azeotropic solvent have been removed in step (B), and a silicon isocyanate compound is produced by reaction with cyanic acid or an isocyanate salt.

[0066] The reaction temperature in step (C) can be below room temperature, but it often takes 5 hours or more at room temperature. On the other hand, at temperatures above 200°C, the reaction time is short, but the product, the silicon isocyanate compound, may undergo side reactions. For this reason, the reaction temperature is preferably room temperature or higher, more preferably 50° C. or higher, and particularly preferably 100° C. or higher. Also, the reaction temperature is preferably 200° C. or lower, more preferably 190° C. or lower, and particularly preferably 180° C. or lower. If the temperature is equal to or higher than the lower limit, the reaction can be completed in a short time (up to about 2 hours), whereas if the temperature is equal to or lower than the upper limit, side reactions of the silicon isocyanate compound can be easily suppressed.

[0067] [Process (D)] In step (D), the liquid containing the silicon isocyanate compound produced by the reaction in step (C) is heated to distill off and recover the silicon isocyanate compound.

[0068] In step (D), the silicon isocyanate compound may be distilled off by heating the liquid under normal pressure, or may be distilled off under reduced pressure. The silicon isocyanate compound may be distilled off first under normal pressure and then under reduced pressure, which tends to improve the yield.

[0069] The liquid temperature during distillation of the silicon isocyanate compound under normal pressure is preferably 100° C. or higher, more preferably 120° C. or higher, and particularly preferably 150° C. or higher, and is preferably 250° C. or lower, more preferably 200° C. or lower, and particularly preferably 190° C. or lower. When the liquid temperature is within the above range, it is possible to produce a silicon isocyanate compound-containing composition without decreasing the purity and yield of the silicon isocyanate compound monomer.

[0070] When the distillation is performed under reduced pressure after distillation under normal pressure, the liquid temperature is preferably 100° C. or higher, more preferably 120° C. or higher, and particularly preferably 150° C. or higher, and is preferably 250° C. or lower, more preferably 200° C. or lower, and particularly preferably 190° C. or lower. The degree of reduced pressure (pressure) is preferably 0.1 kPa or more, more preferably 0.3 kPa or more, and particularly preferably 0.5 kPa or more, and is preferably 101.3 kPa or less, more preferably 90 kPa or less, and particularly preferably 80 kPa or less. When the liquid temperature and the degree of reduced pressure (pressure) are within the above ranges, it is possible to produce a silicon isocyanate compound-containing composition without decreasing the purity and yield of the silicon isocyanate compound monomer.

[0071] In the present invention, water is removed from the liquid by azeotropic dehydration in step (B) before the reaction of the halogenated silicon compound with cyanic acid or isocyanate in step (C). Therefore, the silicon isocyanate compound produced in step (C) contains very little dimer or higher compounds, which are undesirable by-products, and contains a large amount of monomer. Therefore, the composition recovered by distilling off the silicon isocyanate compound in step (D) (silicon isocyanate compound-containing composition) contains a large amount of silicon isocyanate compound monomer.

[0072] Specifically, the silicon isocyanato compound-containing composition recovered in step (D) usually contains 80% by mass or more of silicon isocyanato compound monomer (the purity of silicon isocyanato compound monomer is 80% by mass or more). According to the method of the present invention, it is also possible to obtain a silicon isocyanato compound-containing composition containing 85% by mass or more of silicon isocyanato compound monomer or a silicon isocyanato compound-containing composition containing 90% by mass or more of silicon isocyanato compound monomer at the stage recovered in step (D).

[0073] In this specification, the purity of the silicon isocyanate compound monomer is measured by gas chromatography using a flame ionization detector, and the value is calculated from the area ratio.

[0074] [Distillation process (purification process)] As described above, in the method of the present invention, it is possible to obtain a silicon isocyanate compound-containing composition having a purity of silicon isocyanate compound monomer of 80 mass % or more at the stage recovered in step (D).

[0075] The silicon isocyanate compound-containing composition recovered in step (D) can be further heated and distilled under normal pressure and / or reduced pressure to further increase (highly purify) the purity of the silicon isocyanate compound monomer. For the distillation, a known method can be used, for example, a method using a rectification column.

[0076] In the method of the present invention, the purity of the silicon isocyanato compound monomer in the silicon isocyanato compound-containing composition at the stage recovered in step (D) is already higher than that obtained by conventional methods, and therefore the purity of the silicon isocyanato compound monomer in the silicon isocyanato compound-containing composition after the distillation step is also high.

[0077] Specifically, the purity of the silicon isocyanate compound monomer in the silicon isocyanate compound-containing composition after the distillation process (purification process) is preferably 90 mass% or more, more preferably 95 mass% or more, particularly preferably 98 mass% or more, even more preferably 99.1 mass% or more, and most preferably 99.5 mass% or more.

[0078] The present invention also relates to a method for producing a silicon oxide or a silicon oxide film, which comprises using, as a silicon precursor, the silicon isocyanato compound-containing composition produced by the above-mentioned method for producing a silicon isocyanato compound-containing composition. The silicon isocyanato compound-containing composition produced by the method for producing a silicon isocyanato compound-containing composition of the present invention, and the silicon isocyanato compound-containing composition obtained by purifying such a silicon isocyanato compound-containing composition, have a high purity of the silicon isocyanato compound monomer, and are therefore suitable as a silicon precursor for producing silicon oxide or a silicon oxide film. EXAMPLES

[0079] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

[0080] Manufacturing Example 1 26.0 parts by mass (0.4 mol parts) of sodium cyanate (manufactured by Junsei Chemical Co., Ltd.), 0.4 parts by mass of polyoxyethylene alkyl ether, and 23.8 parts by mass of liquid paraffin (manufactured by Nippon Oil Corporation, product name: Hi-White 350) were mixed with 17.9 parts by mass of toluene, and then azeotropic dehydration of toluene and water was carried out under normal pressure and at a liquid temperature of 110 to 200° C. Then, further azeotropic dehydration was carried out under conditions of a liquid temperature of 200° C. and a reduced pressure of 3 kPa.

[0081] After azeotropic dehydration, 14.9 parts by mass (0.1 mol) of methyltrichlorosilane (Tokyo Chemical Industry Co., Ltd.) was added dropwise and reacted at 170°C for 1 hour. The liquid was then distilled at a liquid temperature in the range of 150 to 190°C under normal pressure, yielding 13.5 parts by mass of a composition containing methyltriisocyanatosilane with a purity of 80% by mass.

[0082] Furthermore, 10.0 parts by mass of the obtained composition was distilled under normal pressure at a liquid temperature in the range of 150 to 190° C. to obtain 5.0 parts by mass of a composition containing methyltriisocyanatosilane with a purity of more than 99%.

[0083] Manufacturing Example 2 39.8 parts by mass (0.6 parts by mole) of sodium cyanate (manufactured by Junsei Chemical Co., Ltd.), 0.3 parts by mass of polyoxyethylene alkyl ether, and 26.3 parts by mass of liquid paraffin (manufactured by Nippon Oil Corporation, product name: Hi-White 350) were mixed with 26.3 parts by mass of ethylbenzene, and then azeotropic dehydration of the ethylbenzene and water was carried out under normal pressure and at a liquid temperature of 110 to 200° C. Then, further azeotropic dehydration was carried out under conditions of a liquid temperature of 200° C. and a reduced pressure of 3 kPa.

[0084] After azeotropic dehydration, 17.0 parts (0.1 mol) of tetrachlorosilane (Tokyo Chemical Industry Co., Ltd.) was added dropwise and reacted at 170°C for 1 hour. The liquid was then distilled off at a liquid temperature of 160 to 180°C and a reduced pressure of 60 to 80 kPa, yielding 13.7 parts by mass of a composition containing tetraisocyanatosilane with a purity of 80% by mass.

[0085] Furthermore, 10.0 parts by mass of the obtained composition was distilled under normal pressure at a liquid temperature in the range of 150 to 190° C. to obtain 5.0 parts by mass of a composition containing tetraisocyanatosilane with a purity of more than 99%.

[0086] Production Example 3 To 26.0 parts by mass (0.4 parts by mole) of sodium cyanate (manufactured by Junsei Chemical Co., Ltd.), 0.4 parts by mass of polyoxyethylene alkyl ether, and 23.8 parts by mass of liquid paraffin (manufactured by Nippon Oil Corporation, product name: Hi-White 350), 14.9 parts by mass (0.1 parts by mole) of methyltrichlorosilane (manufactured by Tokyo Chemical Industry Co., Ltd.) were added dropwise and reacted at 170°C for 1 hour. After that, the liquid was distilled at a liquid temperature in the range of 150 to 190°C under normal pressure, and 13.0 parts by mass of a composition containing methyltriisocyanatosilane with a purity of 70% by mass was obtained.

[0087] Furthermore, 10.0 parts by mass of the obtained composition was distilled under the same conditions as in Example 1, yielding 5.0 parts by mass of a composition containing methyltriisocyanatosilane with a purity of 90% by mass.

[0088] Production Example 4 26.0 parts by mass (0.4 mol parts) of sodium cyanate (manufactured by Junsei Chemical Co., Ltd.), 0.4 parts by mass of polyoxyethylene alkyl ether, 23.8 parts by mass of liquid paraffin (manufactured by Nippon Oil Corporation, product name: Hi-White 350), and 10.0 parts by mass of molecular sieves were mixed and allowed to stand for 24 hours.

[0089] After that, an attempt was made to remove the molecular sieves, but because they were in a slurry state and mixed with sodium cyanate, they could not be separated or dehydrated. [Industrial Applicability]

[0090] The silicon isocyanate compound-containing composition of the present invention contains a silicon isocyanate compound having a Si-NCO bond, and since it easily reacts with compounds containing active hydrogen in the molecule, such as alcohols, primary amines, secondary amines, and carboxylic acids, it can be easily introduced as a polymer modifier or as a component of a polymer, and the properties of silicon can be added to industrial materials. In addition, since it quickly reacts with water, it can react with moisture in the air or adsorbed water present on the surfaces of glass, ceramics, metals, etc., to form a silicon oxide film with high adhesion.

Claims

1. The present invention provides a method for producing a silicon isocyanate compound monomer-containing composition, which comprises reacting a halogenated silicon compound with a cyanate or isocyanate in the presence of one or more solvents selected from the group consisting of liquid paraffin, 1,1,2,2-tetrachloroethane, diisononyl phthalate, and dibutyl phthalate, and an alkylene glycol compound, to produce a silicon isocyanate compound monomer, the method comprising the steps (A) to (D) below: (A) a step of mixing the cyanate or isocyanate, one or more azeotropic solvents selected from the group consisting of benzene, toluene, xylene, and ethylbenzene, the alkylene glycol compound, and the solvent to generate a liquid; (B) A step of heating the liquid, carrying out azeotropic dehydration under normal pressure, and then reducing the pressure to further carry out azeotropic dehydration, thereby removing water and the azeotropic solvent. (C) adding the halogenated silicon compound to the liquid to produce the silicon isocyanate compound monomer. (D) A step of heating the liquid to distill off and recover the silicon isocyanate compound monomer.

2. A method for producing a silicon isocyanate compound monomer-containing composition as described in claim 1, wherein the solvent is liquid paraffin and the azeotropic solvent is one or more solvents selected from the group consisting of toluene and ethylbenzene.

3. 3. The method for producing a silicon isocyanato compound monomer-containing composition according to claim 1 or 2, wherein the produced silicon isocyanato compound monomer-containing composition contains 80 mass% or more of the silicon isocyanato compound monomer.

4. A method for producing a silicon oxide or a silicon oxide film, comprising using a silicon isocyanato compound monomer-containing composition produced by the method for producing a silicon isocyanato compound monomer-containing composition according to any one of claims 1 to 3 as a silicon precursor.

5. The present invention relates to a method for preventing a polymerization reaction of a silicon isocyanate compound monomer produced by reacting a halogenated silicon compound with a cyanate or an isocyanate in the presence of one or more solvents selected from the group consisting of liquid paraffin, 1,1,2,2-tetrachloroethane, diisononyl phthalate, and dibutyl phthalate, and an alkylene glycol compound, the method comprising the following steps (A) to (D): (A) a step of mixing the cyanate or isocyanate, one or more azeotropic solvents selected from the group consisting of benzene, toluene, xylene, and ethylbenzene, the alkylene glycol compound, and the solvent to generate a liquid; (B) A step of heating the liquid, performing azeotropic dehydration under normal pressure, and then further performing azeotropic dehydration under reduced pressure to remove the cyanate or isocyanate, the alkylene glycol compound, and water contained in the solvent, as well as the azeotropic solvent. (C) adding the halogenated silicon compound to the liquid to produce the silicon isocyanate compound monomer. (D) A step of heating the liquid to distill off and recover the silicon isocyanate compound monomer.