JPH02120241A - Production of silicophosphate glass - Google Patents

Abstract

PURPOSE:To obtain the title glass of high purity and high quality in a large form without crack and breakage by hydrolyzing a mixture of a reaction product from alkoxides of rare-earth elements and phosphoric acid or phosphorus alkoxide with silicon alkoxide, then heating the product. CONSTITUTION:Alkoxides of rare-earth elements of the formula M(OR)3 (R is alkyl, aryl, a group forming a chelate; M is at least one metal selected from Nd, Ce, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, and Lu) are allowed to react with phosphoric acid or phosphorous alkoxide to obtain a reaction product. Then, the prorduct is mixed with phosphorus alkoxide and silicon alkoxide to prepare a mixture for producing phosphate glass and the mixture is combined with water in an amount of 0.5 to 2 fold moles based on the total alkoxy groups to conduct hydrolysis, Then, the mixture is aged for several hours to several days to effect polycondensation reactions, further the solvent is removed under reduced pressure above 50 deg.C to give a silicon alkoxide polymer containing rareearth elements and phosphorus. Finally, the polymer is hydrolyzed, subjected to polycondensation reaction and the resultant precursor gel of a silicophosphate glass is dried and calcined at 900 to 1,400 deg.C.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to high-purity glass used in laser oscillation glass.
The present invention relates to a method for producing silicate-based glass that can provide highly homogeneous, large-sized silicate-based glass at low cost.

[Conventional technology]

Many attempts have been made to produce high-purity glass, typically high-purity silica-based glass, by drying a wet gel obtained by hydrolysis and polycondensation reactions of metal alkoxides and firing it (for example, , Japanese Patent Publication No. 61-106
No. 428, Japanese Patent Publication No. 55167143, “Better
Ceramics Through Chemist
ryνo1.32. p47-48), among others, JP-A-61-106428 discloses that metal alkoxide is diluted with a solvent, water containing ammonia is added to produce a sol solution, and then dried to form a porous gel body. , is a glass manufacturing method in which this porous gel body is treated at high temperature to become transparent vitrification.

This method of obtaining glass via sol and gel is called the sol-gel method, and it produces glass of higher quality (higher purity, higher homogeneity) than the conventional melting method, and it is superior to conventional laser glass. It has the advantage that it is cheaper and can be produced in a shorter time than high-purity glass produced by the vapor phase method or melting method used to produce the base material.

This sol-gel method for producing high-purity glass is used for producing high-purity silica-based glass, silicate-based glass, and other glasses.

[Problem to be solved by the invention]

However, in the production of silicophosphate glass by the sol-gel method, there are problems as listed below.

■ When wet gel dries, cracks and cracks occur as the solvent evaporates.

■ In the process of heating the gel and vitrifying it, cracks and cracks occur when residual organic components are burnt out, and residual O
A foaming phenomenon occurs due to the H group.

■ If the hydrolysis rate of other component alkoxides (e.g. rare earth element alkoxides, phosphorus alkoxides) that coexists with silicon alkoxide is different from that of silicon alkoxide, precipitation may occur or the composition may become uneven, causing crank cracking. becomes.

These problems have not been fully resolved in the conventional sol-gel method for producing high-purity silicate glass, and for this reason, the size and manufacturing process of the silicate glass obtained have not been sufficiently resolved. There are limits in terms of shortening. The present invention aims to solve these problems and provide a large-sized, high-quality silicate-based glass that is free from cracks and breaks.

[Means for Solving the Problems] The present invention has been carried out in order to solve the above-mentioned problems, and the present invention is based on partial hydrolysis of rare earth element alkoxides with phosphoric acid, or partial hydrolysis with phosphoric acid in the coexistence of phosphorus alkoxides. By peptizing, a highly dispersed colloidal solution is obtained, and by mixing this solution with a phosphorus compound such as silicon alkoxide and phosphorus alkoxide, the reaction results in a homogeneous multi-component composition for producing silicophosphate glass. is obtained,
By subjecting this mixture to hydrolysis and condensation polymerization, a homogeneous silicophosphate-based glass gel is obtained without precipitating the hydrolysis products of rare earth elements and phosphorous alkoxides alone. By sintering,
The present invention was completed based on the discovery that a large, crack-free, high-purity silicophosphate glass can be obtained.

That is, the present invention hydrolyzes and polycondenses a mixture for producing silicophosphate glass containing a silicon alkoxide, a phosphorus compound, and an alkoxide of a rare earth element to produce a silicophosphate glass matrix gel. A method for obtaining a silicophosphate glass by heating, characterized in that in forming the mixture, an alkoxide of a rare earth element is mixed with phosphoric acid or phosphoric acid and a phosphorus alkoxide in advance and reacted. This is a method for producing acid-based glass.

In addition, when hydrolyzing the mixture for producing silicate-based glass obtained above, silicon alkoxide containing rare earth elements and phosphorus can be obtained by partially hydrolyzing the mixture for producing silicate-based glass. By once producing a multimer and then hydrolyzing this multimer, a large-sized, high-purity, highly homogeneous silicate-based glass without cracks or cracks can be obtained more easily.

The alkoxide of a rare earth element used in the present invention is generally 2M (OR) 3, where R is an alkyl group, an aryl group, a vinyl group, or an organic residue forming a chelate, and M is a rare earth element, such as neodymium or cerium. , samarium, europium, gadolinium, terbium, holmium, erbium, thulium, interbium, and lutetium.

When hydrolyzing a mixture for producing silicophosphate glass containing silicon alkoxide, phosphorus alkoxide, and rare earth element alkoxide, silicon alkoxide, phosphorus alkoxide, or rare earth element alkoxide may be dissolved in an organic solvent. . Alcohols and others are used as the organic solvent.

The amount of water used for hydrolysis of silicon alkoxide, phosphorus alkoxide and rare earth element alkoxide is preferably 0.5 to 2 times the number of alkoxy groups in the alkoxide. The sol obtained by hydrolysis is polycondensed to form a gel.

Polycondensation can be carried out by aging for several hours to several days. The time required for hydrolysis and polycondensation is shortened by using a catalyst. A base is used as a catalyst.

The obtained gel is dried to form a dry gel, but in this case it is preferable to dry it gently so as not to cause cracks or cracks. For example, after drying stepwise at a temperature of 60 to 80°C, the film is finally dried by heating to 150°C.

A silicate-phosphate glass can be obtained by firing the dried gel at 900 to 1400°C.

According to the present invention, a large-sized silicophosphate glass without cracks or breaks can be obtained, and since this glass contains rare earth elements, it can be used for glass for laser oscillation, etc.

[Effect]

A feature of the present invention is that when producing silicate-based glass by the sol-gel method, the rare earth element alkoxide is pre-phosphorized in order to adjust the hydrolysis rate of the rare earth element alkoxide as a dopant and improve the solubility in the solvent. Peptize by reacting with an acid and partially hydrolyzing, uniformly dispersing colloidal particles produced by hydrolysis of rare earth alkoxide in a solvent, mixing this with phosphorus alkoxide and silicon alkoxide, reacting, and uniformly dispersing rare earth elements. This is the point where a multimer of silicon alkoxide containing elements and phosphorus is once produced. Then, by subjecting the mixture for producing silicate-based glass containing this polymer to hydrolysis and polycondensation reactions, a strong wet gel that is homogeneous and has relatively large pores with uniform particle size can be obtained.

As a result, individual precipitation such as precipitation of hydrolysis products of rare earth alkoxides and phosphorus alkoxides is suppressed, and a homogeneous silicophosphate glass is obtained.

In addition, due to the large pore size of the gel, capillary stress due to residual gel from the pores and evaporation of liquid during the drying process is reduced, and the uniform pore size reduces stress. The distribution becomes uniform and the occurrence of cranks and cracks is suppressed.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

However, the present invention is not limited only to these examples.

Example 1 1 g of neodymium triethoxide was added to 100 g of 2-ethoxyethanol, 8.3 g of phosphoric acid (85%) was added dropwise thereto, and the mixture was heated under reflux at 80°C for 3 hours to 1 day to produce a pale purple color. A translucent colloidal solution was obtained. This solution was mixed with 86 g of silicone trimethoxide and 1 part of di-toxyethanol.
It was added dropwise to 55 g of the mixed solution, stirred and reacted at a temperature of room temperature to 90°C, then 8.9 g of water was added, and the mixture was further heated at room temperature to 90°C.
Stir at a temperature of 0'C for 3 days to allow hydrolysis reaction. By removing the solvent from this solution under reduced pressure at a temperature of 90° C. to 160° C., a viscous polymer of silicon methoxide containing neodymium and phosphorus is obtained. 20 g of this polymer was mixed with 18.6 g of ethanol, and p112~
10 and hydrolyzed to form a gel. This was aged for several days at 40°C to 80°C, and
After stepwise drying at a temperature of 0°C, heating to 150″C yielded a dry gel without cranks.B of this dry gel
The peak of the pore radius determined by the ET method was 80, which was a relatively large value. In addition, the peak of the pore radius is very sharp, and the pore diameters are uniform in size. This gel was heated at 1100°C for 5
By baking for hours, NcIzO+-hos-5i
O□ type glass was obtained.

Example 2 1 g of neodymium triethoxide was added to 100 g of 2-methoxyethanol, 8.3 g of phosphoric acid (85%) was added dropwise thereto, and the mixture was heated under reflux at 80°C for 3 hours to 1 day to produce a light purple color. A translucent colloidal solution was obtained. This solution was mixed with 13 g of triethyl phosphate and 15 g of 2-methoxyethanol.
5g of the mixed solution), stirred and reacted at a temperature of room temperature to 90°C, then added 8.9g of water, and further stirred at a temperature of room temperature to 90°C.
Stir at a temperature of 90°C. Then, 58.9 g of silicon ethoxide was added thereto and the mixture was heated under reflux to react, and then the solvent 2-methoxyethanol was heated to 90°C under reduced pressure.
Removal at ~160°C yielded a viscous neodymium and phosphorous containing silicon ethoxide polymer. This multimer 2
0g was mixed with 18.6g of ethanol, and p
It is gelled by adjusting the pH to 112 to 112 and performing hydrolysis. This was aged for several days at 40°C to 80°C, and then dried in stages at a temperature of 60'C to 80°C.
A dry gel without cracks was obtained by heating to 0°C. The peak pore radius of this dried gel measured by the BET method was 80, which was a relatively large value. In addition, the peak of the pore radius is very sharp, and the pore sizes are uniform. 10 times this gel
By baking at 00°C for 5 hours, NhOa-Pz
05-3iO□ type glass was obtained.

[Effects of the Invention] The present invention has the following advantages compared to other methods for producing silicate-based glass.

■ By partially hydrolyzing rare earth element alkoxide with phosphoric acid and reacting it with silicon alkoxide, a homogeneous silicon alkoxide polymer containing rare earth elements and phosphorus is generated, and this is hydrolyzed to gel. , a silicophosphate glass in which rare earth elements and phosphorus are highly dispersed can be obtained.

(2) Since no cracks or cracks occur during gel drying or firing, large silicic acid-based products can be obtained.

■ Compared to the melting method that requires a high temperature of 2000°C,
Since it can be produced at a low temperature of 1400°C to 1400°C, energy savings can be achieved, and silicate-based glass products with high purity and high quality can be obtained.

(2) When producing a laser glass base material, the cost of raw materials is lower and the yield is higher than that of the conventionally used melting method or gas phase method. Furthermore, since the process is simple, it is possible to obtain products of the same quality at a lower cost.

Claims (3)

[Claims] (1) A mixture for producing silicophosphate glass containing a silicon alkoxide, a phosphorus compound, and a rare earth element alkoxide is hydrolyzed and polycondensed to form a silicophosphate glass precursor gel, which is then heated to form a silicophosphate glass precursor gel. In the method for obtaining acid-based glass, in forming the mixture, an alkoxide of a rare earth element is mixed in advance with phosphoric acid or phosphoric acid and a phosphorus alkoxide, and the mixture is reacted with the silicophosphate-based glass. Method. (2) A reaction product obtained by mixing a rare earth element alkoxide and phosphoric acid or phosphoric acid and phosphorus alkoxide in advance and reacting them is mixed with phosphorus alkoxide and silicon alkoxide, and the mixture is added to the mixture for producing silicophosphate glass. Hydrolysis and condensation are carried out by adding water in an amount of 0.5 to 2 times the number of moles of the total alkoxide, and the solvent is removed under reduced pressure at a temperature of 50°C or higher to produce a silicon alkoxide containing rare earth elements and phosphorus. 2. The method for producing a silicophosphate glass according to claim 1, wherein the polymer is obtained and further subjected to hydrolysis and polycondensation reaction to obtain a silicophosphate glass precursor gel. (3) The rare earth element alkoxide used has the general formula M
In (OR)_3, R is an alkyl group, an aryl group,
a vinyl group or a residue forming a chelate, M is neodymium, cerium, samarium, europium, gadolinium, terbium, holmium, erbium, thulium,
The method for producing silicate-based glass according to claim 1, wherein the metal is at least one of ytterbium and lutetium.