JPH02153843A - Phosphate-based glass having treated surface and method for treating surface thereof - Google Patents

Abstract

PURPOSE:To improve durability, especially water resistance without deteriorating characteristics of glass itself by applying a solution containing an Al compound onto the surface of phosphate-based glass and removing a solvent. CONSTITUTION:A solution containing an Al compound as a solute is applied to the surface of phosphate-based glass containing about 50-85wt.% acid compound of phosphorus expressed in terms of P2O5. The resultant glass is then heat-treated to remove a solvent and form phosphate-based glass having a surface layer of the Al compound. The Al compound is selected from organoaluminum chelates, alkoxides, hydrolyzate of the alkoxides, oxyacid salts. The phosphate-based glass is capable of improving durability thereof and preventing weathering without deteriorating optical characteristics thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a phosphate-based glass that has been surface-treated to improve water resistance, and a method for surface treatment thereof.

[Prior Art] Phosphate-based glasses have properties that cannot be obtained with ordinary silicate-based glasses, and are increasingly finding use in high ultraviolet transmittance glasses, laser glasses, glasses for biomaterials, and the like.

[Problems to be Solved by the Invention] Phosphate-based glasses generally tend to have lower chemical durability, particularly water resistance, than silicate-based glasses. A1*
It is known that addition of Os, Btus, Y-Ox, etc. can greatly improve durability due to the composition, but even so, after long-term use, so-called discoloration occurs on the surface, making it difficult to use it as an optical material. In such cases, it is difficult to say that the durability is still sufficient, and it is possible to further improve the durability compositionally by adding additional components such as those mentioned above, but in that case, the desired properties may be degraded. There is a risk that it may cause

[Means for Solving the Problems] As a result of various research and examinations aimed at finding a phosphate-based glass that has sufficient water resistance and does not reduce the desirable properties of the material itself, the inventor has found that It has been found that the above object can be achieved by forming a surface layer containing a specific compound on the surface of an acid salt glass.

Thus, the present invention provides a phosphate glass having a surface layer containing an aluminum compound.

The aluminum compound of the present invention is preferably a compound containing oxygen, more preferably one containing at least one of carbon, hydrogen, and nitrogen. Specifically, organic aluminum chelate compounds such as aluminum acetylacetonado and ethyl aluminum acetoacetate chelate, alkoxides such as aluminum isopropoxide and aluminum butoxide, or oxyacids such as aluminum nitrate and aluminum sulfate are preferred. Organic salts such as aluminum acetate and aluminum chloride, and inorganic salts such as aluminum chloride and aluminum hydroxide can also be used.

Moreover, the surface layer of the present invention may be formed not only from the above-mentioned compounds but also from a chemical reaction of the above-mentioned compounds on the surface of phosphate glass. For example, when an aluminum alkoxide is hydrolyzed on the glass surface and aluminum forms a surface layer mostly in the form of hydroxide or oxide, and some of it is chemically bonded directly to the glass surface, the surface layer is This is preferable because it firmly bonds to the material.

The same applies when an organic chelate compound is used, and a portion of the aluminum may be separated from the organic substance.

The thickness of the surface layer is preferably 10 Å or more. If the thickness is less than this, the effect of suppressing hygroscopicity will not be sufficiently exhibited, and for example, after being left in a high humidity place for a long time, the surface layer may This is undesirable because it may cause discoloration on the surface or deteriorate the properties of the material itself. In addition, in the surface layer,
Components other than aluminum compounds may be included.

A method for forming the surface layer of the present invention is to immerse phosphate glass in a solution containing the above-mentioned aluminum compound or a compound that reacts to become an aluminum compound, and then heat the glass after taking it out. A method in which the solvent is removed by washing is preferred. The solvent may be removed after applying or spraying the solution onto the surface of the phosphate glass. If necessary, the surface layer can be further strengthened by heat treatment at a high temperature.

Various solvents can be used, such as water, alcohol, aliphatic hydrocarbons, and aromatic hydrocarbons.

Specifically, water, methanol, ethanol, 2-propanol, n-hexane, benzene, toluene, xylene, etc. can be mentioned. An acid or alkali may be added to these for the purpose of adjusting pH.

Similar effects can also be obtained by other methods by forming a layer containing an aluminum compound, preferably 10 Å or more, on the surface of phosphate glass.

In the present invention, by providing a surface layer of an aluminum compound on phosphate glass, phosphoric acid is stabilized by aluminum, and water resistance is thought to be improved. Therefore, any glass that contains phosphoric acid has the effect of improving water resistance, but the effect of improving water resistance is particularly large when it is used for glass containing 50% by weight or more of phosphoric acid in terms of P2O. . P, 0. If it contains 85% by weight or more, water resistance may not be sufficient even when the surface layer of the present invention is provided, so it is not preferable.

In the phosphate glass of the present invention, components other than phosphoric acid are not particularly limited. The present invention can be suitably applied to phosphate glass containing, for example, an alkali metal component or an alkaline earth component as a component other than phosphoric acid.

Furthermore, when the phosphate glass of the present invention is used in optical devices, it can improve durability and prevent fading without degrading the optical properties of the glass. When using salt glass, it is possible to omit the need to take strict measures such as moisture proofing.

[Example] <Example 1> A glass containing 71% by weight of P2O6, 21% by weight of CaO, and 8% by weight of A11(h) was prepared by a conventional method,
It was cut out into a plate shape of 10+n+a square with 4 ml and 11 thickness, and the surface was optically polished. This glass was immersed for 5 minutes in 50ml of a 5% by weight solution of aluminum isopropoxide in toluene, then taken out and
By heat-treating at 50° C. for 2 hours, a phosphate-based glass having a surface layer of an aluminum compound was obtained.

The surface condition of this glass was observed after it was left for 500 hours at 60° C. and 90% RH, and the results are shown in Table 1.

<Example 2> A phosphate-based glass obtained in the same manner as in Example 1 was immersed in a 5% by weight solution of aluminum acetylacetonate dissolved in ethanol and 50 mβ of perilla for 5 minutes, and then taken out. A phosphate-based glass having a surface layer of an aluminum compound was obtained by heat treatment at 150° C. for 2 hours.

The same evaluation test as in Example 1 was conducted on this glass, and the results are shown in Table 1.

<Example 3> A phosphate-based glass obtained in the same manner as in Example 1 was immersed for 5 minutes in 50 mβ of a 5% by weight solution of aluminum nitrate nonahydrate dissolved in ethanol, and then taken out. A phosphate-based glass having a surface layer of an aluminum compound was obtained by heat treatment at 150° C. for 2 hours.

The same evaluation test as in Example 1 was conducted on this glass, and the results are shown in Table 1.

Comparative Example 1> Glass obtained in the same manner as in Example 1 was subjected to the same evaluation test as in Example 1 without any treatment. The results are shown in Table 1.

[Effects of the Invention] According to the present invention, durability, particularly water resistance, can be improved without deteriorating the characteristics of phosphate glass.

The characteristics of the optical device using the phosphate glass of the present invention are extremely resistant to deterioration.

Table 1

Claims (6)

[Claims] (1) Phosphate glass having a surface layer containing an aluminum compound. (2) Claim 1 in which the aluminum compound is one or more selected from the group consisting of organic aluminum chelates, alkoxides, hydrolysis products of alkoxides, and oxyacids.
phosphate glass. (3) Phosphate-based glass absorbs phosphorus acid compound P_2O_
Claim 1 containing 50 to 85% by weight calculated as 5
Or 2 phosphate glass. (4) After attaching a solution containing an aluminum compound as a solute to the surface of phosphate glass, removing the solvent.
Surface treatment method for phosphate glass. (5) 1 in which the aluminum compound is selected from the group consisting of organoaluminum chelates, alkoxides, and oxyacids;
5. The surface treatment method according to claim 4, wherein the surface treatment method includes at least one species. (6) An optical device using the phosphate glass according to any one of claims 1 to 3.