JPS62128948A - Method for binding pores of porous glass - Google Patents

Abstract

PURPOSE:To effectively bind the pores without deteriorating the function provided to porous glass by impregnating the pores of the porous glass with a silicon compd. having a specified coupling group and decomposing the silicon compd. in the pores. CONSTITUTION:The porous glass is dipped in vacuum in the soln. of a silicon compd. (tetraisocyanate silane, etc.) having a coupling group shown by the formula, and the inside of the pore is impregnated with the silicon compd. The silicon compd. reacts spontaneously with the silanol group mainly present on the pore surface and the water remaining in the pore, and a precursor capable of forming a three-dimensional glass network structure is formed. Then after most of the unreacted silicon compd. is removed, the substituted silanol group is reactivated into a silanol group by oxidation or hydrolysis. By further repeating the process, a three-dimensional network structure body is formed, and the pores are bound.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for spinning holes in porous glass.

<Prior art> In an attempt to impart functionality to porous glass, methods have been proposed in which various substances are occluded within the pores, but this method does not work unless the pores of the porous glass are used as they are. In order to make the function imparted permanent, it is common to perform a hole-spinning treatment.

Conventionally, the method for spinning holes in porous glass is as follows.

It is common to use high-temperature firing in an electric furnace or the like, and it is well known that this treatment method is effective.

<Problems to be Solved by the Invention> However, in this case, the provided function often causes problems such as functional deterioration or function loss due to the high temperature heating required for the spinning process. This treatment has been a major hindrance to improving the functionality of porous glass. Further, in the conventional treatment method, there was a problem in that the shape of the porous glass changed drastically before and after the treatment.

It is an object of the present invention to provide a method for solving the drawbacks of conventional pore-spinning treatment methods using high-temperature heating, and effectively closing the pores of porous glass, especially when it is difficult to apply pore-spinning treatment using high-temperature heating. It is in.

Means for Solving the Problems〉 The method for spinning porous glass of the present invention impregnates the pores of porous glass with a silicon compound having a -5i-NCO bond, and The method includes a step of decomposing the silicon compound described in No. 41 and forming the pores.

<Preferred embodiments for carrying out the invention> In the pore-spinning treatment method of the present invention, first, 15 tons of porous glass in which various functional imparting substances have been occluded in the pores is prepared.
A silicon compound having a -NCO bond is impregnated into the pores.

Next, the silicon compound impregnated into the porous glass is decomposed within the pores to form a glass structure that extends three-dimensionally within the pores (hereinafter referred to as a three-dimensional glass network structure) and is then spun. Treat the holes.

Jin # To impregnate the pores with this silicon compound.

Generally, impregnation is preferably carried out under vacuum.

The present invention will be described in more detail by citing a porous glass that is composed of a silica skeleton and has many through pores as an example of a porous glass to which the pore-spinning method of the present invention is applied.

The above-mentioned porous glass is produced by heat-treating borosilicate glass having a desired composition to separate the phases into a sodium borate phase and a silica phase, and then treating this with an acid to create an acid-soluble sodium borate phase. Formed by elution. The pore diameter, pore volume, specific surface area, etc. of the porous glass depend on the conditions at the time of phase separation (
(S treatment time, heat treatment temperature, atmosphere, etc.) and acid elution conditions (reaction temperature, reaction time, type of acid, etc.).

In addition, the porous glass is made of a suitable alkyl silicate (St
(OR) 4) (However, R represents an organic group) may be hydrolyzed in water or hydrous alcohol to optionally use a solution in which finely powdered silica is dispersed, or Finely powdered silica and the silica sol may be mixed, and after the silica sol is prepared in this manner, the silica sol is gelled, shaped into a desired shape, dried, and then heated and fired. The pore diameter, pore volume, specific surface area, etc. of the porous glass can be controlled by gelling conditions, drying conditions, heating and firing conditions.

The functional group mainly present on the pore surface of the porous glass is a silanol group (-3i-OH), and this functional group is base plays an important role.

A silicon compound having one Si-NCO bond that is impregnated into the porous glass reacts with the silanol groups on the pore surfaces of the porous glass to produce a precursor capable of forming a three-dimensional glass network. The reaction is expressed by the following formula (1) or (
The process proceeds as shown in 2).

In the reaction format of formula (1), the silicon compound having a -5i-NCO bond also reacts with a very small amount of water remaining in the pores of the porous glass, producing silanol, which further polymerizes to form silica. Form.

This reaction is preferable because it is fairly fast and the by-products are C02 and NH3, both of which are gaseous and do not interact much with the silanol.

An example of a silicon compound having such a -5i-NCO bond is trimethylsilyl isocyanate.

In addition to organosilicon compounds such as dimethylsilyl diisocyanate, methylsilyl triisocyanate, vinylsilyl triisocyanate, and phenyl triisocyanate,
Tetraisocyanate silane, ethoxysilane triisocyanate.

There are tetraisocyanates such as methoxysilane triisocyanate and alkoxysilane triisocyanates. Condensates of these can also be used depending on the purpose, and those that do not interfere with the functions imparted to the porous glass are selected and used. These silicon compounds are used after being diluted as necessary.

The above-mentioned silicon compound reacts with the silanol groups mainly present on the pore surface and the water remaining in the pore, producing a precursor capable of forming a three-dimensional glass network structure. In order to accelerate the reaction until the reaction is complete, it is preferable to perform a post-treatment such as oxidation treatment or hydrolysis treatment.

For example, when organosilicon compounds are used, it is necessary to oxidize the silicon by performing an oxidation treatment to oxidatively remove the self-organic group.

Furthermore, when tetraisocyanate or alkoxysilane triincyanate is used, it is necessary to perform a hydrolysis treatment to oxidize silicon.

This situation is shown in equations (3) to (5).

Formulas (4) and (5) are preferred from the viewpoint of low-temperature processes.

It is also possible to apply a known photolithography process to perform the spinning treatment only on desired locations of the pores of the porous glass.

For example, a photosensitive material such as a photoresist or a photocurable resin is applied to a desired portion of porous glass.

It is also possible to form a desired pattern on the surface or inside of the porous glass using a photolithography process, and to perform the pore-spinning process only on the desired portion using the resist portion as a mask.

The process of the method for spinning porous glass of the present invention is (
Batch processes such as 1) to (5) can be used.

(1) A silicon compound having a -51-NC0 bond is impregnated into the pores of porous glass.

(2) A spontaneous decomposition reaction converts the silanol groups into substituted silanol groups, thereby promoting the formation of a glass network structure within the pores.

(3) Most of the unreacted silicon compounds are removed.

(4) The oxidation reactivates substituted silanol groups to silanol groups by hydrolysis.

(5) Repeat steps (1) to (4) above.

<Effects of the Invention> The method for spinning porous glass according to the present invention does not require high-temperature heat treatment, and can produce porous glass with high efficiency without reducing the functions imparted to the porous glass or causing inconveniences such as loss of functions. Pores can be blocked. Also according to the method of the invention.

The shape of porous glass does not change before and after treatment,
Very desirable.

Example-1 Porous glass was placed under reduced pressure (0.01 Torr) and 1
After being immersed in a solution of 0% tetraisocyanate silane in inpentane and left for 1 hour, the isopentane and tetraisocyanate silane in Ail were cooled under reduced pressure. The pressure was returned to atmospheric pressure (RH=50%) and left for 1 hour. This operation was repeated several times.

As a result, the pore size distribution of porous glass at the time of preparation was 56
The number of cases that used to be in the range of ~60 people has now become almost 10 Å or less.

Example-2 Porous glass (thickness 1 mm) was heated under reduced pressure (0,1 to O,0
After vacuum drying for 8 hours at ITorr).

The glass article was placed in a photocurable composition A having the composition shown below and impregnated for 16 hours, and then the glass article was taken out and the composition A was wiped off from its surface.

Composition of composition A; cyclohexyl acrylate) 30 parts by weight neopentyl glycol diacrylate 40 parts by weight 2.2 bis(4-acryloxyethoxyphenyl)propane 30 parts by weight! 11 parts of benzoin isopropyl ether The glass article was then exposed to ultraviolet light from an ultra-high pressure mercury lamp (250 W).
Exposure was performed for 0 seconds, and the light was passed through the thickness of the glass article to cure the photocurable composition in the portion of the glass article that was irradiated with ultraviolet light. After developing and rinsing with acetone, the porous glass provided with the cured resin pattern was developed under reduced pressure (0.01T).
o r r) After 2 hours, the sample was soaked in a solution of 10% tetraisocyanate silane in impentane, and after 1 hour of several δ, excess impentane and tetraisocyanate silane were removed under reduced pressure. This porous glass is heated to atmospheric pressure (RH=
80%) and left for 1 hour. After repeating this operation several times, the cured resin pattern was removed by heating the glass article to 700° C. in an electric furnace. After cooling, the glass article was immersed in an aqueous solution containing 6% by weight of acetic acid Conoheld for 2 hours, and then sintered at 1100°C. As a result, a glass was obtained in which only the cured resin pattern portion was colored blue. The controllability of the line width of the transparent glass part was good, and the shrinkage rate was 1% or less.

Claims (1)

[Claims] Porous glass comprising the step of impregnating a silicon compound having a -Si-NCO bond into the pores of the porous glass, decomposing the silicon compound within the pores, and forming the pores. Processing method.