JPH07109131A - Production of glass product - Google Patents

Abstract

PURPOSE:To provide production of a glass product capable of prolonging a life of mold and finely molding by using a conventional mold in production of a glass product by press molding glass. CONSTITUTION:A glass product is produced by press molding the glass softened by heating. This production method is characterized by using the glass obtained by replacing part or the whole of hydrogen atom of silanol(SiOH) group existing on the surface of glass with an inactive group. For example, the glass to be molded is reacted with a trialkylchlorosilane or a silane coupling agent to inactivate the surface of the glass.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to precision processing of glass lenses used in optical instruments such as optical measuring instruments, video equipment, audio equipment, office equipment, or glass substrates of discrete track type magnetic recording media. The present invention relates to a method for producing glass products by press molding.

[0002]

2. Description of the Related Art An aspherical lens has a characteristic that it can form a compact and high-performance lens system because it can eliminate aberrations singly, and is an indispensable component for downsizing and high performance of optical equipment. ing. Previously, methods of making aspherical lenses were limited to grinding and polishing. However, the grinding / polishing method has limitations in workability and mass productivity and increases in cost, so that it has only been put to practical use in a limited range.
After that, a press forming method was developed, which makes it possible to manufacture aspherical lenses inexpensively and in large quantities, and its application range is rapidly expanding.

In a hard disk device, which is an external storage device of a computer, the data capacity handled by a personal computer and the like is rapidly increasing, and further improvement in storage density is strongly desired. However, since the recording density of the conventional magnetic recording / reproducing system has reached almost the limit, various new magnetic recording systems have been studied and proposed. Among them, a discreet track system has recently been drawing attention. This is, for example, Nikkei Electronics magazine, No. 586 (1
(Published 993.7.19), pp. 169-182, which is described in detail in a paper entitled "Development of Technology for Increasing Capacity of Hard Disk Drive to that of Optical Disk". Briefly, in the conventional flat substrate, the track pitch is limited because extra recording is made in the area between the tracks due to the stray magnetic field generated from the side surface of the head cap. In the discrete track system, a groove is provided between the recording tracks of the hard disk to prevent the influence of the leakage magnetic field, and the track pitch is increased to increase the recording density. In this method, since a magnetic recording medium in which grooves are regularly engraved by repeating about 1 to several μm is used, a substrate for the magnetic recording medium with grooves is required. There are various possible methods for producing such a grooved substrate. For example, if it is possible to press a glass flat plate with a molding die (male mold) that is precisely processed into a predetermined shape and has excellent durability, it may be a method for manufacturing a grooved magnetic recording medium substrate having excellent industrial productivity. Be expected.

As described above, the press molding method is expected to continue to be used as an important technique for molding glass products. Glass lenses are currently used on the industrial scale by the press molding method. Molding of glass lenses by the press molding method is performed by adding a glass preform heated to a temperature showing an appropriate viscosity with a molding mold that has been precisely processed in advance into a female mold of a predetermined shape, that is, the lens shape of the product. It is performed by pressure molding and transferring the molding surface of the molding mold. Since the state of the molding surface is transferred to the glass lens, the material of the molding mold must be thermally stable at the glass molding temperature, yet have sufficient rigidity at that temperature so that it will not be deformed by the molding pressure. I have to. Also, the molding surface must be capable of being processed to optical surface accuracy. In addition, the molding surface must be such that its surface condition does not change with repeated pressure molding. In order to satisfy such requirements, it is necessary to form the mold with a material having excellent heat resistance, a dense structure, and low reactivity with the molding atmosphere gas and glass. As such a material, various hard films made of refractory metals and their alloys and various high temperature heat resistant ceramics or hard films formed on a substrate have been proposed. For example, JP-A-3-1233
Japanese Patent Publication No. 1 discloses a mold made of a ceramic sintered body containing chromium oxide and zirconium oxide as main components. Further, in Japanese Patent Laid-Open No. 2-199036, SiC
A molding die in which an i-carbon film is formed on the surface of a base material by an ion plating method is disclosed.

[0005]

The above-mentioned molding die exhibits excellent durability when the molding temperature is less than 600 ° C. in the glass lens molding, and the surface condition is almost constant even after the molding is repeated several thousand times or more. It has a track record of not changing. However, when molding barium-containing high-refractive-index, low-dispersion optical glass whose molding temperature exceeds 600 ° C., the mold surface of these existing mold materials rapidly deteriorates, causing surface roughness of the mold and glass. There is a problem that problems such as mold attachment occur.

Further, these existing mold materials have not been sufficient in terms of processing accuracy and service life for manufacturing a substrate of a discrete track type magnetic recording medium. The grooved substrate used in this method has a width of 1 to several μ.
It is necessary to perform processing on the order of m and a depth of 0.1 μm. Therefore, a molding die that should have the reverse image is also required to have the same processing accuracy. However, the molding dies made of various ceramics that have been used so far are all sintered bodies, which are polycrystalline bodies made of particles having a brittleness and a size of about 1 to 10 μm. Therefore, the surface of the micron
If processing is performed on the order of submicrons, partial particles will inevitably fall off, or fine irregularities or undulations on the processed surface will occur due to variations in the crystal orientation of individual particles. As a result, when the above-mentioned sintered body is used as a substrate of a magnetic recording medium, it causes noise and a decrease in recording density. Magnetic recording media are required to be defect-free over the entire substrate having a diameter of at least 2.5 to 1.8 inches. However, the conventional ceramics molding die could not meet this demand at all. Further, as in the above-mentioned Japanese Patent Laid-Open No. 2-199036, even with a mold having a polycrystalline body as a substrate and various coatings, the same problem occurs when processing the polycrystalline body of the mold substrate into a grooved mold. Furthermore, in various metal-based molding dies, the groove portions of the dies are significantly deformed and worn by repeated press molding, and such characteristics are not suitable for industrial production.

In order to deal with such a problem, a material having a structure having no anisotropy in mechanical properties and having no grain boundary, such as high melting point glass, or a polycrystalline material such as various metal materials is used. Therefore, it is conceivable to use a material that has a grain boundary but is less likely to drop out of the particles even if subjected to fine processing because it has plasticity. Then, it is conceivable to process these materials into a grooved mold and coat the surface thereof with various materials that have been proposed as molds as thin films to form a mold. However, even if a mold is produced by such a method, there is a problem of deterioration of the material forming the surface of the forming mold, and it cannot withstand repeated molding of tens of thousands of times. In particular, in a mold having a groove of micron to submicron, the mold surface is damaged and worn around the corner portion of the groove, and the mold is less deteriorated than in the case of press molding of an article having a smooth surface like a lens. It tends to progress rapidly.
For this reason, there is a problem that the life of the mold becomes a bottleneck and the manufacturing cost cannot be reduced. Further, since the molding die whose molding surface is made of an alloy of noble metal has low hardness and low yield stress,
It is insufficient as a long-life mold.

Therefore, an object of the present invention is to extend the life of a mold by using a conventional molding die for press-molding glass to produce a glass product, and to enable fine molding. It is to provide a manufacturing method of a product. In particular, an object of the present invention is to provide a method for producing a glass product, which is suitable for molding barium-containing high-refractive-index and low-dispersion optical glass whose molding temperature exceeds 600 ° C. and fine molding of substrates for magnetic recording media. To do.

[0009]

Means for Solving the Problems That is, the present invention is a method for producing a glass product by press-molding a heat-softened glass to be molded with a molding die, wherein the glass to be molded is:
The present invention relates to a method for producing a glass product, which comprises using glass obtained by substituting hydrogen atoms of some or all of silanol groups existing on the glass surface with an inert group.

The inventors of the present application have examined the damage mechanism of the glass press mold and found that the adhesion between the glass surface and the mold during molding is deeply related to the damage of the mold. First, when the process of press molding is organized, the glass flows along the surface of the mold during molding and is deformed into a shape defined by the surface of the mold. After this, the mold and glass are cooled,
The glass separates from the mold due to the stress generated by the difference in thermal expansion coefficient between the two (so-called mold release step). That is, the glass and the mold are attached by some mechanism from the molding to the mold release. And at the time of mold release, the separation of the glass and the mold does not necessarily occur only at the interface between the two, but from a micro perspective, local glass or mold surface damage occurs, and by repeating this process, It is assumed that the mold surface is gradually deteriorating.

With a combination of a mold of a normal size and glass, the state of being adhered cannot be maintained up to room temperature, and therefore the state of the adhesion interface cannot be analyzed in detail. However, the inventors of the present invention mixed the mold material and the glass powder having a size of about 1 to 10 μm, and heat-treated this at a press molding temperature to analyze a sample with an electron microscope to show the state of the adhesion interface between them. Succeeded in observing in detail. As a result, it was found that there are various states in which both are attached, but they are roughly classified as follows. That is, when the reaction layer is formed at the interface between the mold and the glass and adheres by the reaction layer, the modifying component selectively moves to the interface among the components of the glass, which forms the adhesive layer, and A sharp interface is formed between them and no reaction layer is observed, but when both are bonded,
Is. Of these, in the first two cases, the formation of a bonding layer with mass transfer between the glass and the mold occurs. Therefore, repeated use as a mold is not preferable because the reaction deterioration of the mold surface gradually progresses.

On the other hand, in the third case, even if the glass and the mold are brought into contact with each other at a high temperature, the reaction layer is not formed at the interface, and even if the contact time is extended, the reaction layer appears and the thickness thereof increases with time. No phenomenon was observed and no evidence of mass transfer between glass and mold material was observed. That is, in the third case, although the glass and the mold material are a non-reactive combination, both of them are present in a very limited region near the interface for some reason, probably in a region of 1 to 2 atomic layers. It is considered that a chemical bond is formed between them. Therefore, in this case, the mold deterioration is caused by the formation of a bond at the sharp interface between the glass and the mold, probably involving only 1 to 2 atomic layers of the interface, and the glass and the mold are attached to each other during the cooling process after molding. It is considered that the gradual progress is caused by the fact that the mold surface is locally broken or fatigued by the generated thermal stress, or the glass is broken and a minute glass piece adheres and remains on the mold surface. In particular, when molding a grooved article, stress concentration is likely to occur at the corners of the groove, leading to rapid mold deterioration.

In the case of the adhesion of the glass and the mold material as in the third case, a hydroxyl group which is always present on the glass surface and is very likely to be present on the surface of the molding die made of various metals except precious metals and ceramics. However, the present inventors thought that it was deeply involved. Hydroxyl groups are present on the surface of silicate or borosilicate glass containing SiO ₂ or B ₂ O ₃ as the main component. In particular, the silanol group in which the OH group is bonded to Si begins to dehydrate at 100 ° C or higher,
It is necessary to heat to a high temperature of 600 ° C. or higher in order to almost completely desorb it from the surface. On the other hand, even in the case of non-oxide ceramics or metals other than noble metals, the surface of the molding die is usually oxidized in a few atomic layers, and it is speculated that the surface properties are very close to those of oxides. That is, it is considered that the surface of the mold behaves as an oxide in most cases. However, in the oxide, it is considered that the oxygen portion is partially replaced with the hydroxyl group by the reaction with the moisture in the atmosphere. From these, it is considered that in press molding, both glass and the mold have a considerable amount of hydroxyl groups on their surfaces. When both of these are brought into contact with each other and heated to a high temperature, a dehydration condensation reaction occurs between the hydroxyl groups, and a metal-oxygen-metal type bond is formed between the hydroxyl group and the metal atom to which the hydroxyl group is bonded. If this dehydration condensation reaction occurs only between silanol groups in the glass, Si-OS
There is no problem, only an i-type bond is generated. However, for example, when a dehydration condensation reaction occurs between a silanol group in glass and a hydroxyl group on the surface of the mold, a Si—O—M (where M is a metal atom of the material constituting the mold) type bond is formed. The glass and the mold are attached to each other through this bond. This state is schematically shown below.

[0014]

[Chemical 1]

Assuming that the reaction between the glass and the mold surface occurs due to such a reaction, if at least one surface of the glass and the mold can be made free of hydroxyl groups, the adhesion of the glass and the mold can be suppressed. it is conceivable that. Then, the inventors of the present invention have found that the deterioration of the mold can be suppressed by inactivating the hydroxyl groups on the glass surface so that they cannot react with the hydroxyl groups on the mold surface. Incidentally, it is also possible to inactivate the hydroxyl groups on the molding surface of the molding die. Since the mold is repeatedly heated and cooled, the hydroxyl groups on the surface of the mold are removed almost completely by repeating molding several times. However, in the actual molding, a new glass is supplied as the molding raw material for each molding, so dehydration from the glass surface, which is said to start at about 100 ° C., causes the mold surface to be hydroxylated after each molding. There is a possibility. Therefore, it is more effective to inactivate the hydroxyl groups on the glass surface. Therefore, in the present invention, the silanol groups on the surface of the glass to be molded are inactivated.

As described above, the method itself for producing a glass product by press-molding the glass softened by heating with a molding die is known. In the present invention, the glass to be molded may be a glass preform having a shape similar to that of a glass product or a glass preform such as a glass gob. Further, the glass preform may have a spherical shape, a rugby ball shape, a disc shape or the like when the glass product is a lens. When the glass product is a substrate of a magnetic recording medium, the glass preform has a plate shape,
It can be disc-shaped or the like. The type of glass to be molded is not particularly limited as long as it has a silanol group on its surface. Examples thereof include silicate glass, borosilicate glass, aluminosilicate, and silicate glass.

In the present invention, as the glass to be molded, a glass obtained by substituting hydrogen atoms of some or all of the silanol groups present on the glass surface with an inert molecule (hereinafter sometimes referred to as inactivated glass) is softened by heating. Then, it is pressure-molded by a molding die to obtain a glass product. As a method for replacing the hydrogen atom of the silanol group on the surface of the glass to be molded with an inert group,
There is a method in which the silanol group is reacted with another substance containing an inactive group to replace hydrogen of the silanol group with the inactive group. In general, the silanol group can be substituted with various ions or functional groups for its hydrogen by reactions such as salt formation by reaction with alkali, halogenation, esterification and the like.

Therefore, as one embodiment of the present invention, the glass to be molded is reacted with trialkylchlorosilane to convert the silanol groups on the glass surface into silanolate groups, and then the obtained glass is softened by heating and pressed by a molding die. A method for producing a glass product, which is characterized by molding, can be mentioned.

Examples of trialkylchlorosilanes include trimethylchlorosilane and triethylchlorosilane. Trimethylchlorosilane and triethylchlorosilane are preferable from the viewpoint of reactivity with glass and stability after substitution. Trialkylchlorosilanes are usually gases or liquids. Then, the surface of the glass to be molded is treated with gas or liquid trialkylchlorosilane. The trialkylchlorosilane may be diluted with an appropriate diluent. In the case of gas,
Examples of the diluent include argon, nitrogen, hydrogen and the like. In the case of a liquid, an organic solvent such as various alcohols can be used as the diluent. The conditions for the treatment differ depending on the type of glass, the type of trialkylchlorosilane, the degree of dilution of the trialkylchlorosilane, etc., but it is suitable to be 100 to 100 ° C. for 100 to 10 minutes, for example. The glass whose surface is deactivated by trialkylchlorosilane is then softened by heating and pressure-molded by a molding die. The heating conditions and pressurizing conditions at the time of molding can be appropriately selected from conventional methods depending on the type of glass to be molded. For example, the heating temperature is 300 to 70.
The pressure is 10 to 100 Kgf / cm ^{2 in} the range of 0 ° C.
It is appropriate to set the range to. The reaction between the trialkylchlorosilane and the silanol group on the glass surface is shown below in the case of trimethylchlorosilane.

[0020]

[Chemical 2]

Another method for deactivating the glass surface is to use a silane coupling agent. That is,
As an embodiment of the present invention, the glass to be molded is treated with a silane coupling agent to inactivate the silanol groups on the glass surface, and then the resulting glass is softened by heating and pressure-molded by a molding die. The method for producing a glass product can be mentioned.

By dipping the glass to be molded in an aqueous solution of a silane coupling agent or an alcohol solution, the silanol groups present on the glass surface can be inactivated. The inactive group remaining after replacing the hydrogen atom of the silanol group by the reaction between the silane coupling agent and the silanol group is
Depends on the type of silane coupling agent. After immersion in an aqueous solution or alcohol solution of the silane coupling agent, preferably, after washing with water or alcohol, the surface-inactivated glass to be molded is softened by heating and pressure-molded with a molding die. To make glass products. Here, the method and conditions of heat softening and pressure molding can be appropriately selected from conventional methods and conditions. For example,
It is suitable that the heating temperature is in the range of 300 to 700 ° C. and the pressurizing pressure is in the range of 10 to 100 Kgf / cm ² .

There are various kinds of silane coupling agents as described later. However, in the practice of the present invention, the silane coupling agent is made into an aqueous solution or an alcohol solution, and the glass to be molded is immersed in this for about 1 to 10 minutes, and then washed and dried by a very simple method. The group can be inactivated. The concentration of the silane coupling agent in the solution is
It is suitable to set it in the range of 0.01 to 5%, preferably 0.1 to 1%. If the concentration is less than 0.01%, the amount of silanol groups remaining without being deactivated increases, and the effect thereof tends to shorten the life of the mold in repeated molding. On the other hand, if the concentration exceeds 5%, the following problems may occur. That is, in the actual press molding, the inert groups derived from the silane coupling agent on these glass surfaces are thermally decomposed, and Si atoms contained in the inert groups are fixed on the glass surface as they are through oxygen atoms,
Other functional groups are considered to have a secondary effect of becoming hydrocarbon gas or hydrogen gas and being trapped at the interface between the glass and the mold to further prevent the adhesion between the glass and the mold. However, if the amount of the silane coupling agent bound or adsorbed on the glass surface is too large, the amount of these gases generated during thermal decomposition will be too large and the surface accuracy of the molding surface will be reduced, or the gas will be formed in the outermost glass layer. The amount of SiO ₂ contained in the glass increases, and a layer different from the original optical characteristics of glass is formed. In either case, the optical characteristics of the molded glass may be adversely affected. Therefore, particularly in press molding of an optical lens, it is preferable to keep the concentration of the silane coupling agent solution low, and it is particularly preferable to set it in the range of 0.1 to 1% as described above. For a substrate of a magnetic recording medium which is not required to have optical characteristics, there is no problem even if a solution having a concentration higher than this, that is, up to 5% is used. However, if it exceeds 5%, the molding surface accuracy tends to deteriorate, and the performance as a magnetic recording medium tends to deteriorate.

Many types of silane coupling agents are already commercially available. However, if the molecular weight is too large, the amount of gas produced as a by-product during thermal decomposition becomes too large and adversely affects it. Therefore, a silane coupling agent having a molecular weight of 300 or less is suitable. Specific examples of such a silane coupling agent are as follows. However, these are merely examples, and the present invention is not limited to these. Vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- Glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane,
γ-methacryloxypropylmethyldiethoxysilane,
γ-methacryloxypropyltriethoxysilane, N-
β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane , Γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-
Mercaptopropyltrimethoxysilane

As is apparent from what has been described above, the present invention is a method for manufacturing glass products such as lenses, and various optical lenses including aspherical lenses, substrates for magnetic recording media, and prisms. The optical article and the like can be produced by this method. The optical lens, the prism, and the like can be manufactured by heating and softening the glass to be molded, which has been surface-treated as described above, by a conventional method and press-molding it with a molding die. Further, in the production of a substrate for a magnetic recording medium, it is possible to use, as a molding die, a base material such as quartz glass, various heat-resistant alloys, etc., which has been processed on a surface having a predetermined shape in advance, and coated with a thin film of various materials. preferable. A wide variety of materials can be selected for the coating layer. Typical examples are MgO, Al ₂ O ₃ , TiO ₂ , and Cr.
₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , In ₂ O ₃ , SnO ₂ ,
Examples thereof include oxides such as HfO ₂ , Si ₃ N ₄ , SiC, and transition metals, particularly nitrides, carbides, and borides of elements of Groups 4 and 5 of the periodic table. Furthermore, the disk-shaped glass substrate with grooves formed according to the present invention is further formed with a known underlayer, an intermediate layer, and a lubricating layer in some cases, thereby forming a magnetic disk known as a so-called hard disk device. A high density medium for a recording device can be manufactured.

The present invention will be described in more detail with reference to the following examples. Examples Example 1 and Comparative Example 1 SK-5 glass preform (a diameter of about 15) which is a kind of barium-containing borosilicate glass for optical use having a low dispersion and a high refractive index.
glass having a substantially spherical shape of 80 mm) was exposed to trimethylchlorosilane vapor at 80 ° C. for 10 minutes to prepare a glass preform in which the silanol groups on the surface were inactivated (Example 1).
An untreated glass preform was also prepared for comparison (Comparative Example 1). These glass preforms were repeatedly molded as a lens under the following conditions using a molding die made of a chromium oxide sintered body in which zirconium oxide was dispersed, as described in JP-A-3-12331, and had a diameter of about 23 mm and a thickness of about 23 mm. A 5 mm lens was molded. Molding conditions: Molding temperature 650 ° C. Molding pressure 10 MPa Pressurization time 20 seconds Atmosphere Nitrogen When the glass preform of Example 1 was used, the mold surface was not roughened after repeated molding over 20,000 times. On the other hand, when the glass preform of Comparative Example 1 was used, the glass adhered to the molding die in the first press, and the surface of the molding die after the glass was peeled off was the sintered body particles forming the molding die. The surface of the mold was roughened due to the falling off, and molding was impossible.

Examples 2 to 6 and Comparative Examples 2 to 3 Ethanol solutions of vinyltrimethoxysilane having the respective concentrations shown in Table 1 were prepared. A SK-5 glass preform was immersed in this solution for 5 minutes, washed with alcohol, and then dried to prepare a glass preform whose surface was inactivated. The same mold as in Example 1 (Examples 2 to 5,
Using Comparative Examples 2 to 3) and an aluminum oxide sintered body (Example 6), press molding was performed under the same conditions as in Example 1. As a result, in Examples 2 to 6, molding could be repeated 20,000 times or more. The surface roughness (Rmax) of the molded glass preform is 0.008 μm or less in Examples 2 to 4 and 6, and 0.01 to 0.012 in Example 5.
was μm. On the other hand, in Comparative Example 2, the glass partially adhered to the mold by pressing three times. Further, in Comparative Example 3, the glass could be molded 20,000 times or more without sticking to the mold, but the surface roughness of the molded glass was as large as 0.02 to 0.03 μm, and the optical performance was not satisfactory. .

[0028]

[Table 1]

Examples 7 to 10 Vinyltrichlorosilane (Example 7), vinyltriethoxysilane (Example 8), γ-methacryloxypropyltriethoxysilane (Example 9), γ-aminopropyltrimethoxysilane (Example) A 1% ethanol solution of Example 10) was prepared. Each of the SK-5 glass preforms was immersed in these solutions for 5 minutes, washed with alcohol, and then dried to prepare four types of glass preforms whose surfaces were inactivated. The same mold as in Example 1 was used, and press molding was performed under the same conditions as in Example 1. In any case, the molding could be repeated 20,000 times or more, and the surface roughness (Rmax) of the molded glass was 0.008 μm or less.

Example 11, Comparative Example 4 Flatness of 5 μm, surface roughness (Rmax) of 0.1 μm, flattened and polished, 2.5 mm (63.5 mm) in diameter, 10 mm thick metal chrome disk, width, Grooves having a height of 1.4 μm and a height of 0.2 μm were concentrically formed by etching with a pitch of 2 μm. This was heat-treated in air at 650 ° C. for 30 minutes to form a film of chromium oxide on the surface to obtain a molding die.
Aluminosilicate glass disk (diameter 2.5 inches, thickness 1 mm) that has been polished to a surface roughness (Rmax) of 0.05 μm is used as a 0.5% alcohol solution of vinyltrimethoxysilane. It was immersed for 5 minutes, washed with alcohol, and then dried to inactivate the surface (Example 11). For comparison, a glass disk (Comparative Example 4) not treated with the silane coupling agent was also prepared. A mold having a chromium oxide film was backed up with a silicon nitride sintered body (using silicon nitride as a base), and the glass disk was press-molded under the following conditions. Molding conditions: Molding temperature 850 ° C. Molding pressure 20 MPa Pressurizing time 20 seconds Atmosphere Nitrogen

In Example 11 in which the surface-inactivated glass was molded, the surface of the mold was not roughened and the glass was not adhered even after the molding was repeated 20,000 times or more. Further, when the glass surface formed when the number of repetitions was repeated 20,000 times was observed with a scanning electron microscope, the entire surface of the glass was found to have a width of 0.6 μm on a disk having a diameter of 2.5 inches and a thickness of about 1 mm.
It was confirmed that grooves having a depth of m and a depth of 0.2 μm were formed at a pitch of 2 μ and that there were no defects such as chipping and defective depth. On the other hand, in Comparative Example 4 in which the surface of the glass was not inactivated, the entire surface of the mold and the glass was adhered in the third molding, and the molded glass was also fine from the first molding to the surface. There was a chip.

[0032]

According to the present invention, when a glass product is press-molded using a conventionally used mold, the life of the mold can be made longer than before. In particular, a molding temperature of 600 having excellent optical characteristics such as high refractive index and low dispersion
Even in the press molding of a barium-containing borosilicate glass lens having a temperature of ℃ or more or a glass substrate of a discrete track type magnetic recording medium which requires fine groove processing, the life of the molding die can be remarkably extended.

Claims (7)

[Claims] 1. A method for producing a glass product by press-molding heat-softened glass to be molded with a molding die, wherein a part or all of silanol (SiOH) existing on the glass surface is used as the glass to be molded. A method for producing a glass product, which comprises using a glass in which a hydrogen atom of a group is substituted with an inert group. 2. The glass to be molded is reacted with a trialkylchlorosilane to convert the silanol groups on the glass surface into silanolate groups, and then the obtained glass is softened by heating and pressure-molded by a molding die. Method for manufacturing glass products. 3. The method according to claim 2, wherein the trialkylchlorosilane is trimethylchlorosilane or triethylchlorosilane. 4. A glass characterized in that the glass to be molded is treated with a silane coupling agent to inactivate the silanol groups on the glass surface, and then the resulting glass is softened by heating and pressure-molded by a molding die. Product manufacturing method. 5. The silane coupling agent is vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ. -Glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- Methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane,
N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-
Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane,
5. The method according to claim 4, which is one or more compounds selected from the group consisting of γ-mercaptopropyltrimethoxysilane. 6. The glass product is a lens, as claimed in any one of claims 1 to 5.
The manufacturing method according to any one of 1. 7. The manufacturing method according to claim 1, wherein the glass product is a substrate of a magnetic recording medium.