JPH10292048A - Production of organic trialkoxysilane condensate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an org. trialkoxysilane condensate having a medium mol.wt. by conducting the hydrolysis and condensation of an org. trialkoxysilane by using a canon exchange resin contg. no water. SOLUTION: 'Medium mol.wt.' means a wt. average mol.wt of 1,000-50,000. The org. trialkoxylsilane is a silicon compd. of the formula: RSi(OR')<3> and/or a low condensate obtd. by the partial hydrolysis and condensation of this silicon compd. and can be used without any specific limitation. Methanol, etc., are used as the solvent in the reaction in a wt. of 0.1-10 times that of the trialkoxysilane. The cation exchange resin used is an H-type cation exchange resin having sulfonic, carboxylic, or acidic hydroxyl groups, and the amt. of it used is not specifically limited. The amt. of water used in the hydrolysis is 1.5 mol or lower based on 1 mol of the trialkoxysilane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a medium-sized organic triode used for the production of heat-resistant, electrically insulating and flexible sheet, bulk or coating material having excellent transparency. It relates to an alkoxysilane condensate.

[0002]

2. Description of the Related Art Compounds having an alkoxy group bonded to silicon are considered to be applicable to various uses by being hydrolyzed and condensed into condensates of various forms, and have been receiving attention in recent years. The hydrolysis condensation method is also being studied. For example, JP-A-3-126612 discloses a method for hydrolyzing and condensing alkoxysilane.
A method using a water-containing H-type cation exchange resin as a catalyst is introduced.

[0003]

However, in the method described in the above-mentioned publication, a large excess of water than the theoretical amount required for the hydrolytic condensation is introduced into the reaction system together with the ion exchange resin, and the productivity is increased for several days. Is a very bad thing.
Generally, the molecular weight of the condensate obtained by hydrolytic condensation of alkoxysilane depends on the amount of water introduced into the reaction system. However, the water in the water-containing cation exchange resin is easy to volatilize, and if the container is left open or the storage condition of the container is poor, it evaporates and the water content changes. Can not.

[0004] For this reason, a water-containing cation exchange resin cannot be applied to those in which the amount of water used in the reaction must be precisely controlled in order to precisely control the molecular weight of the condensate. In particular, it is necessary to add less water than the theoretical amount of water required for the hydrolytic condensation to cause a reaction.
A narrow range of 00 to 50,000, for example, a molecular weight of about 1
It is difficult to obtain a condensate controlled to be at 000. On the other hand, in order to control the amount of water in the reaction system without being affected by the water in the ion exchange resin, it is conceivable to add precisely measured water using a dried cation exchange resin. Comparative Example 1 of JP-A-3-126612
As described in U.S. Pat. No. 6,075,098, it is described that the solution prepared in such a reaction system gels after 10 days, and it was difficult to sufficiently control the molecular weight and obtain a condensate having good storage stability.

[0005]

Means for Solving the Problems The present inventors have made intensive studies in view of the above problems. As a result, by performing hydrolytic condensation of the organic trialkoxysilane using a specific cation exchange resin, a condensate of a medium molecular weight of the organic trialkoxysilane is efficiently and stably, that is, a molecular weight of 1,000 to The inventors have found that about 50,000 condensates can be obtained, and have reached the present invention. That is,
In the present invention, when an organic trialkoxysilane is hydrolyzed and condensed into a condensate, a weight-average molecular weight of 1,000 to 50,000 is present in the presence of a cation exchange resin containing no water.
A method for producing an organic trialkoxysilane condensate, characterized in that the condensate is 0.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

(Raw Materials) First, the organic trialkoxysilane used in the present invention is a silicon compound represented by the general formula RSi (OR ′) ₃ and / or a low condensate obtained by partially hydrolyzing and condensing these compounds. Can be used without particular limitation.

In the above formula, R and R ′ are each an organic group, and R is hydrogen or methyl, ethyl, propyl,
C1-C10 alkyl groups such as butyl and decyl, vinyl groups and phenyl groups are particularly preferred, and R 'is preferably C1-C4 alkyl groups such as methyl, ethyl, propyl and butyl. is there. In addition, if these organic trialkoxysilanes are most, besides this, a small amount of other alkoxysilanes, for example, tetraalkoxysilane,
The dialkoxysilane may be mixed. Specifically, the present invention can be practiced without any substantial problem if the content of these other alkoxysilanes is 30 wt% or less, preferably 10 wt% or less.

At the time of hydrolysis and condensation, an organic solvent used as a diluent for dissolving the organic trialkoxysilane and water is an alcohol having 1 to 4 carbon atoms such as methanol, ethanol, propanol and butanol, or a ketone such as acetone. It is preferable to use an organic solvent that dissolves the organic trialkoxysilane and water, such as ethers such as THF, dioxane, and methoxymethanol.

When the boiling point of these organic solvents is too high,
When it is distilled off after the hydrolysis or when the obtained condensate is formed into a molded body, it tends to remain in the molded body. When a large amount of solvent remains in the molded article, the strength and solvent resistance of the molded article are reduced. In order to prevent this, it is preferable to select an organic solvent that does not have a very high boiling point. When the amount of the solvent to be used is too small, the viscosity of the reaction solution increases, which affects the operability. On the other hand, if the amount is too large, the reaction time becomes longer. For this reason, the amount of the solvent is preferably 0.1 to 10 times and 0.2 to 5 times the weight of the organic trialkoxysilane.

The present invention is characterized in that a cation exchange resin is present in performing the hydrolysis and the condensation. Since the cation exchange resin is expected to function as an acidic catalyst for promoting hydrolysis, it is preferable to use an H-type cation exchange resin having a sulfone group, a carboxyl group, an acidic hydroxyl group, and the like. Depending on the state of the pores, the cation exchange resin includes a gel type, a porous type having more pores, and a macro recursive type, and any type can be used without limitation. The mold tends to accelerate the reaction and is desirable.

More specifically, H-type cation exchange resins (gel type) such as "DIAION SK1BH" and "SK104H" manufactured by Mitsubishi Chemical Corporation, "PK216H" (porous type), and "RCP160H" (macro recursive) Type), and “Nafion NR-50” manufactured by Wako Pure Chemical Industries, Ltd., and the like. Cation exchange resins other than H-type, such as Na-type, may be converted to H-type with an acid before use. The amount of the cation exchange resin used is not particularly limited, and the preferred amount varies depending on the size of the pores and the strength of the acid. The reaction proceeds in a short time even if the amount of the strongly acidic compound is small, but the amount of the weakly acidic compound should be increased since the reaction time is long.

In the present invention, the cation exchange resin is used as one containing substantially no water. The method of removing water from the cation exchange resin is not particularly limited. For example, drying with a dryer or an organic solvent compatible with water such as alcohols, ketones such as acetone, DM
Water may be removed by immersing and / or washing with formamides such as F to replace water with an organic solvent.

The amount of water used for hydrolysis is not more than the theoretical amount required for hydrolyzing and condensing trialkoxysilane, that is, 1.5 mol times or less based on trialkoxysilane. If water is used in excess of the stoichiometric amount, all of the trialkoxysilane will be hydrolyzed, and condensation will proceed to form a large molecular weight condensate. As a result, the viscosity will be higher than necessary and the gel will be easily formed. Specifically, it is 1.5 mole times or less, preferably 0.1 mole times or less with respect to 1 mole of trialkoxysilane.
It is 3-1.5 mole times, particularly preferably 0.5-1.5 mole times, more preferably 0.8-1.4 mole times, most preferably 0.9-1.3 mole times. Within this range, the condensate described below can be stably obtained. If the organic solvent used contains water, it is necessary to consider the amount of water.

(Condensation) The hydrolysis of the organic trialkoxysilane can promptly progress the condensation by heating. In this case, the solvent may be distilled off,
It may be refluxed. The presence of the H-type ion exchange resin and the heating time also affect the condensation reaction. For example, if the H-type ion exchange resin is removed at an early stage, the progress of the condensation reaction is slowed.
In order to use the organic trialkoxysilane condensate for coating or film formation, the weight average molecular weight is preferably from 1,000 to 50,000, more preferably from 5,000 to 40,00, and the weight average molecular weight is preferably 000-20,000 are most preferred.

(Uses) The organic trialkoxysilane condensate of the present invention thus obtained can be suitably used for various uses such as addition to thin films, bulk materials, and paints.
Typically, an organic trialkoxysilane condensate can be used after being diluted with a solvent having a relatively low boiling point that dissolves the condensate, such as a lower alcohol such as methanol, ethanol, or propanol, or acetone.

The dilution concentration at this time is 1 in terms of a non-volatile component.
The content is preferably 0 to 80% by weight. In the case of solidifying in a container to form a molded product, the container used for molding should be made of a material having low affinity with the organic trialkoxysilane condensate, such as polymethylpentene, in consideration of the releasability after molding. It is preferred to use. The molding is preferably performed at 50 to 200 ° C. Since the organic trialkoxysilane of the present invention has a slow condensation rate, the higher the heating temperature, the faster the molding. However, when the temperature exceeds 500 ° C., the organic substance partially present is decomposed and may be colored brown or black.

In order to speed up the reaction without increasing the temperature,
There is also a method of adding a catalyst such as a heavy metal or a metal carboxylate. As a kind of metal, tin, lead, iron, cobalt, manganese, zinc and the like have a catalytic effect. As metal carboxylates, zinc acetate, dibutyltin diacetate, dibutyltin dilaurate and the like are effective catalysts. Further, a fine filler such as colloidal silica, fumed silica, and titanium white may be added to the organic trialkoxysilane condensate of the present invention. Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 A porous H-type cation exchange resin "P" manufactured by Mitsubishi Chemical Corporation
K216H "was immersed in 30 g of 50 ml of methanol overnight, then the methanol was removed by decantation, and the ion exchange resin was transferred to a glass column.
Was washed with methanol to prepare an ion exchange resin containing no water.

1 equipped with a stirrer, thermometer and condenser
113.5 g of methyltrimethoxysilane and 70 ml of methanol were placed in a 000 ml four-necked flask, and the mouth was capped. Thereafter, the mixture was cooled in an ice water bath with stirring, and the internal temperature was reduced to 10 ° C. or lower. Next, PK21 containing no water
6H was put in the flask and suspended. Thereafter, desalted water was added in an amount of 1.05 mol times water per 1 mol of methyltrimethoxysilane. After the addition, the mouth was capped and stirred at room temperature for 2 hours.

Thereafter, the flask was heated with stirring in an oil bath at 70 ° C., and methanol was refluxed for 5 hours.
After cooling to 40 ° C. or lower, KP216H was filtered through Nutsche. The filtrate was a clear, colorless, smooth liquid. The methanol was removed from this with an evaporator to obtain a methyltrimethoxysilane condensate as a viscous liquid. The liquid diluted with benzene was measured by GPC and found to have a weight average molecular weight of 10,400.

This methyltrimethoxysilane condensate is diluted to 20 wt% with a solvent in which acetone and methanol are mixed at a volume ratio of 1: 1 and poured into a polymethylpentene dish, and dried at 80 ° C. And reacted for 2 days. A thin colorless molded product was formed in the Petri dish, and a flexible colorless and transparent sheet was obtained when it was taken out of the Petri dish. When this condensate was left at room temperature for 2 months, there was no apparent change in viscosity.

Example 2 The same operation as in Example 1 was carried out, except that 113.5 g of methyltrimethoxysilane was replaced by 126 g of vinyltrimethoxysilane, to obtain a condensate of vinyltrimethoxysilane. Obtained. This condensate was diluted to a concentration of 20 wt% with a solution obtained by mixing acetone and methanol in a volume ratio of 1: 1 and poured into a polymethylpentene petri dish, and kept at 80 ° C. for 2 weeks to form a film. . The obtained film was colorless, transparent and flexible, and the strength of the film was measured to be 17 MPa.

Example 3 The methyltrimethoxysilane condensate prepared in Example 1 was diluted with isopropyl alcohol to obtain a solution having a nonvolatile content of 20%. The solution was applied to a microscope slide glass by a dipping method, the solvent was removed at 120.degree.
Heated for minutes. A colorless and transparent coating film was obtained.

[0024]

According to the present invention, a condensate of a medium molecular weight of an organic trialkoxysilane can be stably produced.

Claims (2)

[Claims] 1. A method for producing a condensate by hydrolyzing and condensing an organic trialkoxysilane in the presence of a cation exchange resin containing no water, and having a weight average molecular weight of 1,000 to 50,000.
A method for producing an organic trialkoxysilane condensate, wherein the condensate is a condensate of the formula 2. The organic trialkoxysilane according to claim 1, wherein the hydrolysis and condensation of the organic trialkoxysilane are carried out using 1.5 mol times or less of water per mol of the organic trialkoxysilane. Production method.