JP2004123520A - Method for manufacturing glass product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass product by which a glass product free of surface tarnish, clouding or cracking can easily be obtained without requiring large-scale equipment. <P>SOLUTION: The method for manufacturing a glass product includes a step of heat-softening a glass preform and a step of press-forming it with a shaping die. A glass preform having a surface free energy of ≥60 mJ/m<SP>2</SP>is subjected to a heat softening step and then to a press-forming step, or a surface layer is formed on a glass preform having surface free energy of ≥60 mJ/m<SP>2</SP>and the glass preform is subjected to a heat softening step and a press-forming step. <P>COPYRIGHT: (C)2004,JPO

Description

{Circle over (1)} The present invention relates to a method for producing a glass product, particularly a glass optical element, by press-molding a heat-softened glass material in a molding die.

モ ー ル ド As a method for easily forming a precision optical glass element with high productivity, there is a mold press method. In the mold press method, a glass material for molding that has been melt-solidified or cold-worked in advance and formed into a predetermined shape is put into a molding die, and it is pressed in a state where it can be molded by heating and softening, and molded. In this method, a glass element is cooled by cooling the glass element held in a mold. According to this method, since a precision-processed mold is used, polishing of the formed glass element is not required.

(4) When a glass element is formed by a mold press method, a glass material for molding and a mold adhere to each other at a high temperature equal to or higher than the softening point of glass. Therefore, a reaction occurs at the interface between the glass and the mold, and a part of the glass is fused to the surface of the mold, cloudiness or cloudiness occurs on the surface of the glass element, and defects such as cracks are generated. Was difficult to get.

To solve these problems, a method of modifying the surface of a glass material in advance is known.
Japanese Patent Application Laid-Open No. 9-71424 (Patent Document 1) discloses a method of exposing a glass material for molding under a reduced pressure of 10 ³ Pa or less at a temperature such that its viscosity is in a range of 10 ⁹ to 10 ¹⁴ poise. Have been. In this method, the cause of cloudiness or cloudiness on the surface of the glass element is interpreted as the reactivity or volatilization of the surface of the molding glass material, and as described above, heat treatment under reduced pressure is performed to reduce these. Do.

According to this method, although a certain effect can be seen, the heat treatment under reduced pressure may cause the surface layer state of the forming glass material to be non-uniform, or may be repeatedly formed with the same mold, for example, 500 times. When performing continuous molding more than once, partial fusion occurs on the surface of the mold or the surface of the release film provided on the mold, the defect rate increases rapidly, and a satisfactory result is not obtained. Was.

Further, a method of forming a film on the surface of a glass material for molding is known.
Japanese Patent Publication No. 2-31012 (Patent Literature 2) describes a method for preventing fusion by forming a carbon film on at least one of surfaces of glass and a mold facing each other.
Japanese Patent Application Laid-Open No. 8-277125 (Patent Document 3) discloses a method of forming a metal oxide of group IIIA such as yttrium oxide or cerium oxide on a glass surface by vacuum evaporation or sputtering.
Japanese Patent Application Laid-Open No. H11-236225 (Patent Document 4) discloses a method of forming a sulfide or selenide such as Mo, W, and Nb as a film on a glass surface by vacuum evaporation or sputtering.

JP-A-9-71424 Japanese Patent Publication No. 2-31012 JP-A-8-277125 JP-A-11-236225

According to the method described in the above patent document, although a certain effect is seen, repeated molding with the same mold, for example, when continuous molding is performed 1000 times or more, gradually, or suddenly after molding optical glass The device surface was clouded, clouded, and cracked, and was not sufficiently satisfactory.
The present invention has been made in view of the above circumstances, and is a glass product capable of obtaining a glass product in which fusion during press molding and clouding, turbidity, or cracks on the surface of a molded product due to the fusion are suppressed. It is an object of the present invention to provide a method for producing the same.

The present invention for solving the above problems is as follows.
[Claim 1] A method for producing a glass product, comprising a step of heat-softening a preformed glass material and a step of pressure-forming with a forming die, wherein the glass has a surface free energy of 60 mJ / m ² or more. A production method comprising subjecting a material to a heat softening step and then to a pressure molding step.
Environment the claims 2] preformed glass material, the surface free energy is washed so that 60 mJ / m ² or more, and heat softening step to start, can maintain a 60 mJ / m ² or more surface free energy The manufacturing method according to claim 1, wherein the holding is performed.
[Claim 3] A method for producing a glass product, comprising a step of heat-softening a preformed glass material and a step of press-forming with a forming die, wherein the glass has a surface free energy of 60 mJ / m ² or more. A method for producing a glass product, comprising subjecting a material to a heat softening step and a pressure molding step after forming a surface layer on the material.
[4] The method according to [3], wherein the surface layer is a thin film containing carbon as a main component and having a thickness of 0.1 nm or more and 1 μm or less.
[Claim 5] The preformed glass material is washed so that its surface free energy becomes 60 mJ / m ² or more, and the surface free energy of 60 mJ / m ² or more can be maintained until a surface layer is formed. The manufacturing method according to claim 3, wherein the method is held in an environment.

As described above, according to the present invention, a glass material is press-molded with a molding die, and when manufacturing an optical element, the surface free energy of the preformed glass is 60 mJ / m ² or more. By using a glass material with a surface layer formed on a material or a molding glass material with a surface free energy of 60 mJ / m ² or more, stable production of glass products without clouding, cloudiness, and / or cracking can do.

The present invention is a method for producing a glass product, comprising a step of heating and softening a preformed glass material, and a step of pressure molding with a molding die, wherein the first aspect has a surface of 60 mJ / m ² or more. A glass material having free energy is subjected to a heat softening step and then to a pressure molding step. The second embodiment is that a surface layer is formed on a glass material having a surface free energy of 60 mJ / m ² or more. After that, it is subjected to a heating softening step and a pressure forming step. In any of the embodiments, a glass material having a surface free energy of 60 mJ / m ² or more is used as the preformed glass material.

It is empirically known that poor appearance such as clouding of the molded optical element and cracks are mainly caused by fusion between the molding glass material and the mold surface or the release film surface provided on the mold surface. Have been. Further, as a result of a detailed investigation, the present inventors have found that most of the fusion is generated from foreign matters adhering to the surface of the mold or the surface of the release film. As a result of surface analysis using ESCA or the like, the main component of the foreign substance was identified as an organic substance not contained in the glass material for molding. As a result of further investigation, dirt present on the surface of the molding glass material is suddenly generated during pressing, or a trace amount of dirt is gradually concentrated on the mold surface or the release film surface by repeatedly pressing. I knew it would be done.

Also, even when a carbon film was formed on the surface of the glass material for molding, the number of presses at which the fusion failure increased rapidly was prolonged, but the fusion failure also increased rapidly after about 1000 continuous presses. Therefore, when the mold surface where the fusion failure was rapidly increased was examined, foreign matter was attached in the same manner as described above, and as a result of surface analysis using ESCA or the like, the major component of the foreign matter was found to be the glass material for molding. It was an organic substance that was not included. It was found that even when a carbon film was formed on the surface of the glass material for molding, a slight amount of dirt on the surface of the glass material for molding was concentrated on the surface of the mold or the surface of the release film by repeatedly pressing.

Since the amount of organic dirt on the surface of the glass material for molding is very small, it is difficult to directly evaluate it. However, the present inventors analyzed the organic stain on the surface of the molding glass material by using the Owens-Wendt-Kaelble method from the measurement of the wetting angle of pure water, CH ₂ I ₂ , glycerin, isopentane, perfluorohexane, etc. It has been found that it is possible to quantitatively evaluate the surface free energy. It has also been found that a molding glass material having a small surface free energy value has a large amount of organic stains. Further, the transition of the defective fusion rate due to the surface energy of the glass material for molding and the number of presses was investigated.

The surface free energy can be measured using a known contact angle measuring device. That is, the wetting angle (contact angle) of the surface of the measurement object can be measured and calculated using two different types of the above liquids. For example, evaluation of the surface free energy using the Owens-Wendt-Kaelble method based on the measurement of the wetting angle of pure water and CH ₂ I ₂ can be performed as follows. The surface free energy (γ) is given by the sum of a solid or liquid dispersion force (γ) d and a solid or liquid polar interaction force (γp).

(1)式を固体の表面自由エネルギー（γs）で考えると、

Considering equation (1) in terms of solid surface free energy (γs),

となる。ここで添字のsはSolidを表わす。
　また、同様に液体では

It becomes. Here, the subscript s represents Solid.
Also, for liquids

であり、添字LはLiquidを表す。膜の表面自由エネルギーは、水とCH₂I₂（ジヨードメタン）の2種類の液体を用い、それぞれを固体上に同量滴下し、求めた接触角から表面自由エネルギーを算出する。
　Owens-Wendt-Kaelble法により、以下の計算式を用いた。

And the subscript L represents Liquid. The surface free energy of the film is calculated by using two kinds of liquids, water and CH ₂ I ₂ (diiodomethane), dropping the same amount on a solid, and calculating the surface free energy from the obtained contact angle.
The following formula was used according to the Owens-Wendt-Kaelble method.

　尚、2種類の液体のγ_L ^d及びγ_L ^pはそれぞれ表１の文献値を使用し、(3)式より2種類の液体それぞれのγ_Lを求める。

It should be noted that γ _L ^d and γ _L ^p of the two types of liquids use the literature values shown in Table 1, respectively, and γ _L of each of the two types of liquids is obtained from equation (3).

　例えば、水の接触角が104.9°、ジヨードメタンの接触角は72.0°であれば、(4)式のθに代入し、その他のエネルギー値は表1の値を用いる。その結果

For example, if the contact angle of water is 104.9 ° and the contact angle of diiodomethane is 72.0 °, it is substituted into θ of the equation (4), and the other energy values are as shown in Table 1. as a result

　上式(6)によって得られたγs^dを(5)式に代入すると

Substituting γs ^d obtained by the above equation (6) into the equation (5)

　　　
となり、これら(6)及び(7)式の値を(2)式に代入することにより

By substituting the values of equations (6) and (7) into equation (2),

　従って、固体の表面自由エネルギーγsが22.30mJ/m²と求められる。

Therefore, the surface free energy γs of the solid is determined to be 22.30 mJ / m ² .

Table 2 shows the results of examining changes in the surface free energy and the defective fusion rate depending on the number of presses for the glass material for molding glass A made of borate optical glass. From this result, it can be seen that when the surface free energy of the forming glass material is 60 mJ / m ² or more, the occurrence of fusion is dramatically reduced. In addition, the same investigation was performed on a case where a carbon film was formed on the surface of the molding glass material, and the results are shown in Table 3. Even in this case, it can be seen that in the case where the surface layer is formed on a molding glass material having a surface free energy of 60 mJ / m ² or more, the occurrence of fusion is significantly reduced.

The present invention has been made based on the results of this finding, and by using a molding glass material having a surface free energy of 60 mJ / m ² or more, it is possible to dramatically reduce fusion defects. it can.
If a glass material having a surface energy of less than 60 mJ / m ² is continuously subjected to press molding, dirt, adhesion to the mold surface or the release film surface provided on the mold surface, concentration easily occurs even with a small number of presses. Become. As a result, dirt (organic matter) reacts at the interface, and fusion to the mold surface or release film surface of the glass material, especially a large number of sub-μm-sized fusions, occurs. The finished mold surface or release film surface is rough and uneven. By transferring this, defects such as cloudiness and cloudiness occur in the molded optical element. In addition, cracking of the optical element occurs from the fused portion as a base point. The above table shows that it is more preferable to use a molding glass material having a surface free energy of 65 mJ / m ² or more.

A molding glass material having a surface free energy of 60 mJ / m ² or more can be obtained by precisely cleaning the molding glass material. In addition, minute organic dirt in the air adheres to and adheres to the surface of the glass material for molding, and the organic dirt increases with the passage of time, and the surface free energy also increases with the lapse of time after cleaning. descend. Therefore, it is also important to store the forming glass material in a clean environment after washing and before pressing.

As methods for precision cleaning of glass materials for molding, there are physical methods of dirt removal, dirt lift-off with substrate surface etching and wet methods based on the principle of dissolution of dirt, dirt represented by UV ozone treatment and oxygen plasma treatment. A dry method or the like utilizing oxidative decomposition of can be appropriately used.

In the wet method, usually, “physical peeling” → “lift-off of dirt accompanying etching of the substrate surface” → “dissolution of dirt” can be performed in this order.

In the “physical peeling”, for example, a technique of ultrasonic waves or brushing is used. By adding a chemical solution such as a detergent (acidic, neutral, or alkaline) for enhancing the cleaning effect, dirt can be efficiently removed by a synergistic effect of physical action and chemical action. Specifically, for example, it can be performed as follows.
Ultrasonic wave and brushing; Ultrasonic wave is several KHz to several MHz, brushing is chemical solution such as optical brushing detergent (acidic, neutral, alkaline); general optical detergent solution (anionic surfactant, nonionic surfactant) Such)
Washing time and temperature; 0.5 to 15 minutes, 20 to 70 ° C
After washing, rinsing is performed, and pure water is generally used for rinsing.

In “lift-off of dirt accompanying etching of the base material surface”, the forming glass material is immersed in a solution containing an acidic or alkaline agent suitable for etching the surface of the forming glass material. Means such as ultrasonic waves or heating may be used to enhance the effect. Acidic or alkaline chemicals; solvent with added chemicals such as ammonium bicarbonate, ammonium bifluoride, ammonium carbonate, ammonium hydroxide; pure water cleaning time and temperature; 0.5-60 minutes, 20-70 ° C after this cleaning Rinsing is also performed, and pure water is generally used for rinsing.

In addition, in the “dissolution of dirt”, particularly in the dissolution of organic dirt, a glass material for molding is immersed in an organic solvent such as ethyl ether, acetone, or isopropyl alcohol. Means such as ultrasonic waves or heating may be used to enhance the effect. Cleaning time and temperature; 0.5 minutes to 15 minutes, 20 ° C. to 70 ° C. Rinsing (rinsing) generally uses isopropyl alcohol, and after rinsing, vapor drying is used.

It is preferable that the glass material for molding, which has been subjected to precision cleaning and has a surface free energy of 60 mJ / m ² or more, is isolated from an organic contamination source which causes a decrease in surface free energy. As a method for storing the glass material for molding therefor, a clean environment from which organic pollutants are eliminated, for example, an environment in which the total organic carbon concentration in the air is equal to or less than 1000 μgC / L is preferable. More preferably, it is 500 μgC / L or less, and still more preferably 100 μgC / L or less. The term “total organic carbon concentration” as used herein refers to the total organic carbon concentration of a water sample obtained by bubbling atmospheric air into pure water at a flow rate of 1 L / min. Using a known TOC (total organic carbon) measuring device. Is measured, and the value obtained by converting the total organic carbon concentration in 1 L of air from the measured value is used.

Specifically, if the total amount of bubbled atmospheric air is 20 L and the TOC of the water sample is 100 μg / L, the total organic carbon concentration in the air is 100 μg C / L = 20 μC / L. In order to keep the total organic carbon concentration at 1000 μg C / L or less, it is preferable to isolate the glass material for molding so that organic substances such as alcohol do not enter the storage or transportation environment of the glass material.

It is also appropriate to control the environmental cleanliness of the forming glass material. For example, an environment equivalent to a clean room or a clean booth of ISO class 5 or less is preferable. More preferably, class 4 is preferable, and class 3 or lower is preferable. The class mentioned here is based on ISO-14644 (Part1). The exponent of the number of particles having a particle size of 0.1 μm or more in one cubic meter is taken as a power of 10, and when it is 10 ^x particles / m ³ , it is expressed as ISO class x.
The cleanliness can be measured using a known particle counter (light scattering coefficient machine) by a method based on ISO-14644.
In the case of dry cleaning, a known oxygen plasma cleaner, hydrogen plasma cleaner, UV ozone cleaner can be used, or argon ion etching can be used.

As described above, organic substances existing in the air also adhere to the surface of the molding glass material, causing a reduction in surface free energy. Therefore, in order to reliably supply the glass material for molding with 60 mJ / m ² or more surface free energy for press molding, prior to heat softening the glass material for molding, the surface free energy for each lot of molding glass material It is preferable to perform a sampling inspection. Then, as a result of the inspection, only the molding glass material of the lot having a minimum value of the surface free energy of 60 mJ / m ² or more is subjected to the heat softening step. The molding glass material of the lot having a minimum surface free energy of less than 60 mJ / m ² is subjected to precision cleaning again. Preferably, the storage and transport environment is such that the variation in surface free energy of a plurality of glass materials in a lot has a median value of ± 5 mJ / m ² , more preferably a median value of ± ² mJ / m ^2. To clean.

組成 There is no particular limitation on the composition and shape of the glass material to which the present invention is applied. However, optical glass of a glass material which is likely to be fused, that is, a fluorophosphate, a phosphate, a borate, a borate having a high reactivity with a molding surface (or a release film on the molding surface). The present invention is particularly effective for a glass material composed of:

Further, in particular, the above-mentioned composition having high reactivity with a concave meniscus, a biconcave lens shape, or a molding surface (or a release film on the molding surface) that is difficult to release, and further, a glass material having a high press temperature (Eg, Tg is 550 ° C. or more) and the molding surface of the mold or the release film is easily consumed, the surface free energy of the preformed glass is 60 mJ / m ² for the purpose of accelerating the release. A surface layer can be formed on the molding glass material described above. More preferably, a surface layer is formed on a glass material having a surface free energy of 65 mJ / m ² or more.

Before the surface free energy is 60 mJ / m ² or more molding glass material, and precision cleaning as described above, and store it in a clean environment organic pollution, further, to form a surface layer on the glass material for molding Next, a surface free energy sampling inspection is performed for each lot of molding glass material. Then, only the forming glass material of the lot having the minimum value of the surface free energy of 60 mJ / m ² or more is subjected to the surface layer forming step. The molding glass material of the lot having a minimum surface free energy of less than 60 mJ / m ² is subjected to precision cleaning again. Similarly to the above, it is preferable to form the surface layer when the variation in the surface free energy within the lot is equal to or less than the median value ± 5 mJ / m ² , preferably ± ² mJ / m ^{2 in} advance.

が The surface layer will be described later, but when the surface layer is formed, the surface free energy is lower than before the surface layer is formed. However, when the surface layer is formed, the contamination rate of the glass material is greatly reduced as compared with the glass material having no surface layer. Therefore, even if the storage management is not performed in a clean environment as described above, the predetermined effect ( This is advantageous in that an effect of preventing defects such as cloud and cloudiness from occurring in the molded optical element can be obtained.

表面 Examples of the surface layer provided on the glass material include a thin film containing carbon as a main component and a self-assembled film. Thin films mainly composed of carbon include diamond, diamond-like carbon film (hereinafter, DLC), hydrogenated diamond-like carbon film (hereinafter, DLC: H), and tetrahedral amorphous carbon film (hereinafter, ta-C). It is selected from a tetrahedral amorphous carbon film (hereinafter, ta-C: H), an amorphous carbon film (hereinafter, aC), a hydrogenated amorphous carbon film (hereinafter, aC: H), and the like.

The thin film containing carbon as a main component is formed by CVD, DC-plasma CVD, RF-plasma CVD, microwave plasma CVD, ECR-plasma CVD, optical CVD, laser CVD. It is formed by a method such as a plasma CVD method such as a method, an ionization evaporation method such as an ion plating method, a sputtering method, an evaporation method, and an FCA (Filtered Cathodic Arc) method. The thickness of the thin film containing carbon as a main component may be about 0.1 nm to 1 μm, and particularly preferably 0.5 nm to 100 nm. If the film thickness is too small, the releasability tends to decrease. If the film thickness is too large, the effect of preventing fusion, clouding, cloudiness and / or cracking tends to be saturated, and the surface of the glass material for molding tends to be saturated. The layer state becomes non-uniform, and the variation tends to increase.

Self-assembled monolayers: Hiroyuki Sugimura, Osamu Takai; Japan Society for the Promotion of Science, 131st Committee of Thin Films, 199th Research Material 2000.2.1 p.34-39, Seunghwan Lee, Young-Seok Shon, Ramon Colorado, Jr. , Rebecca L. Guenard, T. Randall Lee and Scott S. Perry; Langmuir, Vol. 16 (2000), p. 2220-2224, etc., and as shown in FIG. Is a film 7 formed by self-arranging and organizing on the surface of the film-forming substrate 6 and having a coverage of almost 100%. The self-assembled film can be formed by immersing the glass material in, for example, a coating solution for a self-assembled film.

(4) The glass material provided with the self-assembled film forms an organic molecular aggregate having a uniform molecular arrangement on its outermost surface, and can extremely reduce friction with a contacting object.

For example, by selecting a specific organic molecule and exposing the glass material to a solution containing the organic molecule, for example, a solution in which the organic molecule is contained in a non-polar organic solvent at a predetermined concentration, and adjusting the reaction conditions, An organic monomolecular film with uniform orientation is formed. Since a film is formed by the organic molecules reacting and arranging with the group on the surface of the substrate on which the film is to be formed, a film having an extremely high coverage can be formed. For efficient film formation, pretreatment of the glass surface may be performed. Examples of the organic molecule include a reactive organic silicon-containing compound, a reactive organic sulfur-containing compound, a reactive organic fluorine-containing compound, and a reactive organic nitrogen-containing compound. The functional group in which these organic compounds react spontaneously and spontaneously with the surface of the substrate (glass) to be formed is mainly a -Cl group in an organic silicon-containing compound (reaction formula (1) described later). , An organic sulfur-containing compound mainly contains a -H group or a (S-S) group (reaction formulas (2) and (3) described later), and an organic nitrogen-containing compound mainly contains a -H group (reaction formula (described below) 4)). For example, the reaction between the functional group (circle part) of the molecule 4 in the solution 3 and the surface of the substrate 5 can be as follows.

When there is a group having a Cl element in an organic compound such as a chlorotrialkylsilane compound, a dichlorodialkylsilane compound, a trichloroalkylsilane compound, etc., this becomes a functional group, and as shown in the reaction formula (1), a film-forming substrate ( It reacts spontaneously and spontaneously with -OH groups on the surface of the glass 5 to form a self-assembled film using the compound as a starting material on the surface of the substrate 5 on which the film is to be formed.

　尚、清浄なガラス表面は反応性が高く、ガラスをクリーンな大気に曝すと空気中の水分子と反応し、ガラス表面は全面的に-OH基に覆われているため、上記の反応が進むのである。
　また、例えばアルカンチオール化合物の場合には、化合物中のS元素と結合しているH元素が官能基となり、反応式（２）のとおり、被成膜基材３の表面の−OH基と自己的・自発的に反応し、被成膜基材３の表面に前記化合物を出発原料とする自己組織化膜が形成される。

The clean glass surface has high reactivity, and when the glass is exposed to the clean air, it reacts with water molecules in the air, and the above reaction proceeds because the glass surface is entirely covered with -OH groups. It is.
In the case of an alkanethiol compound, for example, the H element bonded to the S element in the compound becomes a functional group, and as shown in the reaction formula (2), the —OH group on the surface of the film-forming base material 3 Reacts spontaneously and spontaneously to form a self-assembled film using the compound as a starting material on the surface of the substrate 3 on which the film is to be formed.

　更に、例えばジアルキルジスルフィド化合物の場合には、化合物中のS−S結合が官能基となり、反応式（３）のとおり、被成膜基材３の表面の−OH基と自己的・自発的に反応し、被成膜基材３の表面に前記化合物を出発原料とする自己組織化膜が形成される。

Further, for example, in the case of a dialkyl disulfide compound, the S—S bond in the compound becomes a functional group, and as shown in the reaction formula (3), spontaneously and spontaneously interacts with the —OH group on the surface of the substrate 3 on which the film is to be formed. As a result, a self-assembled film using the compound as a starting material is formed on the surface of the film-forming substrate 3.

　ジメチルアンモニウム化合物、アルキルジメチル（ジメチルアミノ）シラン化合物の場合には、化合物中のＮ元素に結合するH元素が官能基となり、反応式（４）のとおり、被成膜基材３の表面の−Cl基と自己的・自発的に反応し、被成膜基材３の表面に前記化合物を出発原料とする自己組織化膜が形成される。

In the case of a dimethylammonium compound or an alkyldimethyl (dimethylamino) silane compound, the H element bonded to the N element in the compound becomes a functional group, and as shown in the reaction formula (4), − It reacts spontaneously and spontaneously with the Cl group to form a self-assembled film using the compound as a starting material on the surface of the film-forming substrate 3.

　尚、この成膜を行う場合には、ガラス表面を、塩素を含むクリーンな乾燥雰囲気に曝し、その表面が−Cl基で覆われた状態として、上記の反応を進める。
　上述のとおり、自己組織化膜の形成するためには、自己的・自発的に被成膜基材表面の−OH基や−Cl基と反応する官能基を有する化合物を、その官能基の反応性を保全した状態で、被成膜基材表面と接触させることが必要である。例えば、自己組織化膜膜の原料となる有機化合物を、水分や塩素を相当量含んだ雰囲気中に保管すると、官能基の反応性が失われやすい。従って、有機化合物は、官能基の反応性を維持する状態で保管することが好ましい。
　自己組織化膜を形成するための反応は、反応速度が大きいことが好適である。反応式（１）〜（４）で述べた、−Cl基、−H基、　（S―S）基は、反応速度が優れて大きいため好適である。他方、官能基がOR基（アルコキシ基）など、反応速度が小さい基をもつ出発原料を用いると、下記反応式（５）の進行が遅く、成膜速度が相対的に小さい。

When performing this film formation, the glass surface is exposed to a clean dry atmosphere containing chlorine, and the above-described reaction proceeds with the surface covered with -Cl groups.
As described above, in order to form a self-assembled film, a compound having a functional group that reacts spontaneously and spontaneously with a -OH group or -Cl group on the surface of a substrate on which a film is to be formed is reacted with the functional group. It is necessary to make contact with the surface of the substrate on which the film is to be formed while maintaining the property. For example, when an organic compound serving as a raw material for a self-assembled monolayer film is stored in an atmosphere containing a considerable amount of moisture or chlorine, the reactivity of the functional group is likely to be lost. Therefore, the organic compound is preferably stored in a state where the reactivity of the functional group is maintained.
The reaction for forming the self-assembled film preferably has a high reaction rate. The -Cl group, -H group, and (SS) group described in the reaction formulas (1) to (4) are preferable because the reaction rate is excellent and large. On the other hand, when a starting material having a group having a low reaction rate, such as an OR group (alkoxy group), is used as the functional group, the progress of the following reaction formula (5) is slow, and the film formation rate is relatively low.

　また、本発明に用いる自己組織化膜の出発原料としての有機分子は、末端に上記官能基をもつが、他の末端（上記官能基を結合末端とすると、表面末端側）にアルキル基、アリール基、ビニル基、エポキシ基、またはフッ素を有することができる。好ましくは、アルキル基、アリール基である。このような基をもつと、融着やワレ、クモリの抑止された、良好なプレス成形を行なうことができる。
　自己組織化膜の出発原料として用いる、反応性の有機ケイ硅素含有化合物、反応性有機硫黄含有化合物、反応性有機フッ素含有化合物及び反応性有機窒素含有化合物としては、例えば、以下の化合物を挙げることができる。但し、これらの化合物に限定されるものではなく、ガラス素材において自己組織化膜を形成できる物質であれば良い。

Further, the organic molecule as a starting material of the self-assembled film used in the present invention has the above-mentioned functional group at the terminal, but has an alkyl group and an aryl group at the other terminal (the surface terminal side when the above-mentioned functional group is a binding terminal). It can have groups, vinyl groups, epoxy groups, or fluorine. Preferably, they are an alkyl group and an aryl group. With such a group, it is possible to perform favorable press molding in which fusion, cracking and clouding are suppressed.
Examples of the reactive organic silicon-containing compound, the reactive organic sulfur-containing compound, the reactive organic fluorine-containing compound, and the reactive organic nitrogen-containing compound used as a starting material of the self-assembled film include the following compounds. Can be. However, the material is not limited to these compounds, and may be any substance that can form a self-assembled film in a glass material.

As chlorotrialkylsilane compounds, chlorotrimethylsilane, chlorotriethylsilane, pentafluorophenyldimethylchlorosilane, tert-butyldimethylchlorosilane, (3-cyanopropyl) dimethylchlorosilane, chlorotrifluoromethylsilane and the like and derivatives thereof, dichlorodialkyl As silane compounds, dichlorodimethylsilane, dichloromethylvinylsilane, dichlorodifluoromethylsilane, dichloro-n-octadecylmethylsilane, n-octylmethyldichlorosilane, dichlorocyclohexylmethylsilane and the like, and derivatives thereof, trichloroalkylsilane compounds such as trichloroalkylsilane Vinylsilane, n-octadecyltrichlorosilane, isobutyltrichlorosilane, n-octafluorodecyltrichloro Silane, cyanohexyltrichlorosilane and the like and derivatives thereof, phenyltrichlorosilane as trichloroarylsilane compound, trimethyl (dimethylamido) silane, triethyl (dimethylamido) silane, pentafluorophenyldimethyl as alkyldimethyl (dimethylamido) silane compound (Dimethylamido) silane, trifluoromethyl (dimethylamido) silane, tert-butyldimethyl (dimethylamido) silane, (3-cyanopropyl) dimethyl (dimethylamido) silane and the like and derivatives thereof, and alkanethiol compounds as 1 -Butanethiol, 1-decanethiol, 1-fluorodecanethiol, o-aminothiophenol, 2-methyl-2-propanethiol, n-octadecanethiol, etc. And derivatives thereof, dialkyl sulfide compounds such as ethyl methyl sulfide, dipropyl sulfide, n-hexyl sulfide, fluoroethyl methyl sulfide, phenyl vinyl sulfide and the like, and derivatives thereof, ethyl phenyl sulfide and derivatives thereof, and dialkyl disulfide compounds. , P-tolyl disulfide, diallyl disulfide, methylpropyl disulfide, fluoromethylpropyl disulfide, difurfuryl disulfide and derivatives thereof, methylphenyl disulfide and derivatives thereof, dimethylammonium compounds such as dihexadecyldimethylammonium acetate, dioctadecyl Dimethyl ammonium acetate, dieicosyl dimethyl ammonium bromide Dimethyldioctadecylammonium iodide, dioctafluorodecyldimethylammonium acetate, dimethyldioleylammonium iodide and the like and derivatives thereof.

The self-assembled film according to the present invention can be formed by immersing preformed glass in an organic solution (hereinafter referred to as a coating solution) in which the above-mentioned organic molecules as starting materials for the self-assembled film are dissolved. . The solvent of the organic solution is preferably an anhydrous organic solvent. This is for the purpose of avoiding that the starting organic molecule loses its reactivity due to the reaction with the water molecule. In addition, when a solvent having a polar group is used, a bond with an organic molecule is similarly formed and the organic molecule may lose reactivity. Therefore, it is preferable to select a non-polar solvent as the solvent. That is, the solvent used should maintain the reactivity of the functional groups of the organic molecules.
Specifically, for example, an anhydrous non-polar organic solution such as hexane, an anhydrous organic solution such as toluene and chloroform, and a mixed solution thereof are preferable.

On the other hand, when the starting compound of the self-assembled film is diluted with a polar organic solvent such as alcohols, as shown in the following reaction formula (6), the functional group reacts with the -OH group in the alcohol to form a functional group. In some cases, the group is lost, and the reaction with the -OH group or -Cl group on the surface of the substrate on which the film is to be formed becomes difficult to occur. Therefore, it is preferable that the organic solvent has no -OH group or the like.

　上記コーティング溶液において、出発原料の濃度は、0.01〜10ｗｔ％の範囲とすることが好ましく、0.1〜5ｗｔ％の範囲とすることがより好ましい。濃度が、小さすぎると被覆率が不充分になるが、大きすぎても被覆率は上がらず、下がる傾向がある。例えば、自己組織化膜の出発原料をベンゼン、トルエン、キシレン、ヘキサン等の無水有機溶剤で希釈して調整したコーティング溶液にガラスを1分間程度浸漬した後、コーティング溶液から取り出し、洗浄後、室温〜100℃の温度で30分程度、乾燥する。

In the above coating solution, the concentration of the starting material is preferably in the range of 0.01 to 10 wt%, more preferably in the range of 0.1 to 5 wt%. If the concentration is too low, the coverage becomes insufficient, but if it is too high, the coverage does not increase but tends to decrease. For example, after immersing the glass in a coating solution prepared by diluting the starting material of the self-assembled film with an anhydrous organic solvent such as benzene, toluene, xylene, and hexane for about 1 minute, removing the glass from the coating solution, washing, and then washing at room temperature to Dry at a temperature of 100 ° C for about 30 minutes.

In addition to the immersion method, the self-assembled film can be obtained by exposing the preformed glass to steam, mist, gas or the like containing the starting material of the self-assembled film.
In the self-assembled film, as a result of a reaction between the self-organized and spontaneous functional groups (circle) and the surface of the film-forming substrate 6, as shown in FIG. It is arranged neatly on the surface of the material 6. Therefore, when a self-assembled film is formed, it can be detected by surface analysis such as IR-RAS which exhibits a peak reflecting the IR activity of the bonded state with respect to the arrangement of atoms having regularity. .
In other words, in the IR-RAS analysis, when a self-assembled film is formed, a peak derived from the regular arrangement of molecules is observed (for example, as shown in FIG. 4). No peak is observed in the case of a film having no specific molecular arrangement.

A self-assembled film is called a self-assembled monolayer (SAM) in English, and may refer to a monolayer formed on the surface in a single film formation process. It is also possible to form a multi-layer, and the self-assembled film of the present invention includes not only a mono-layer but also multi-layers 9 and 10 as shown in FIG.

に お い て In the present invention, the thickness of the self-assembled film formed on the surface of the glass material is preferably 0.1 nm or more and 30 nm or less. If the thickness of the self-assembled film is less than 0.1 nm and the thickness of the self-assembled film exceeds 30 nm, the effect of preventing clouding, cloudiness and / or cracking on the pressed lens surface tends to be reduced. More preferably, the thickness of the self-assembled film is 0.5 nm or more and 20 nm or less. The thickness of the self-assembled film can be measured by, for example, ESCA or ellipsometer.

1 and 2 are cross-sectional views schematically showing a glass material for molding used in the present invention. As shown in FIG. 1, the glass material for molding used in the method of the first embodiment of the present invention is a glass material in which the surface free energy of the surface 2 of the preformed glass material 1 is 60 mJ / m ² or more. It is. Further, as shown in FIG. 2, the glass material for molding used in the method of the second embodiment of the present invention has a surface free energy of 60 mJ / m ² or more. It is a glass material on which the layer 3 is formed.

In the method for producing a glass product of the present invention, the preformed glass material described above is heated and softened, and then pressure-formed by a forming die. The pressure molding of the glass material can be performed by a known means. For example, a glass material is introduced into a mold that has been precisely shaped, heated to a temperature at which the viscosity is equivalent to 10 ⁸ to 10 ¹² poise, softened, and pressed, thereby forming the molding surface of the mold into a glass material. Transfer to Alternatively, a glass material whose viscosity has been increased to a temperature equivalent to 10 ⁸ to 10 ¹² poise in advance is introduced into a precisely shaped molding die, which is pressed so that the molding surface of the mold is pressed into the glass material. Transfer to The atmosphere during molding is preferably non-oxidizing. Thereafter, the mold and the glass material are cooled, and when the temperature is preferably equal to or lower than Tg, the mold is released and the molded optical element is taken out.

The mold type base material, in addition to SiC, WC, TiC, TaC, BN, TiN, AlN, Si 3 N 4, SiO 2, Al 2 O 3, ZrO 2, W, Ta, Mo, cermet, sialon , Mullite, carbon composite (C / C), carbon fiber (CF), WC-Co alloy and the like.

Furthermore, a mold having a release film on the surface of the base material can be used. As the release film formed on the surface of the base material, a diamond-like carbon film (hereinafter, DLC), a hydrogenated diamond-like carbon film (hereinafter, DLC) can be used. : H), tetrahedral amorphous carbon film (hereinafter, ta-C) hydrogenated tetrahedral amorphous carbon film (hereinafter, ta-C: H), amorphous carbon film (hereinafter, aC), hydrogenated amorphous carbon film (hereinafter, taC) hereinafter, aC: H) carbonaceous film, Si ₃ N ₄ selected from such, TiAlN, TiCrN, CrN, Cr X N Y, AlN, nitride film or a composite multi-layer film or a laminated film of TiN or the like (AlN / CrN, A film such as a noble metal alloy film containing platinum as a main component such as TiN / CrN), Pt-Au, Pt-Ir-Au, and Pt-Rh-Au can also be used.

The release film is formed by a plasma CVD method such as a DC-plasma CVD method, an RF-plasma CVD method, a microwave plasma CVD method, an ECR-plasma CVD method, an optical CVD method, a laser CVD method, and an ion plating method. Alternatively, a method such as ionization vapor deposition, sputtering, vapor deposition, or FCA (Filtered Cathodic Arc) may be used.

The glass product manufactured by the manufacturing method of the present invention can be, for example, an optical element such as a lens, a mirror, a grating, a prism, a microlens, a laminated diffractive optical element, and is a glass molded article other than the optical element. You can also.

[Example]
Hereinafter, the present invention will be described in more detail with reference to Examples.
Example 1
For optical element molding materials that have been cleaned with high precision using a commercially available optical precision cleaning machine by the wet cleaning method and that have been stored in a highly clean environment in nitrogen gas even after cleaning, for each cleaning / storage lot The surface free energy was evaluated using the Owens-Wendt-Kaelble method by measuring the wetting angles of pure water and CH ₂ I ₂ . For all lots, the minimum value of the surface free energy was 68 mJ / m ² or more, and the surface energy claimed in the present invention was 60 mJ / m ² or more.

The high-precision cleaning by the wet cleaning method was performed as follows.
1) City water tank (ultrasonic) 1 minute → 2) City water tank (ultrasonic) 1 minute → 3) Cleaning tank (ultrasonic) 1 minute → 4) Pure water tank (ultrasonic) 1 minute → 5) Pure water tank (ultra) 1 minute → 6) Isopropyl alcohol tank (ultrasonic wave) 1 minute → 7) Isopropyl alcohol tank (ultrasonic wave) 1 minute → 8) Vapor drying tanks 1) to 7) are performed at 30 ° C.

Storage in an environment with high cleanliness in nitrogen gas was specifically performed under the following conditions. The optical element molding material was set in a vacuum desiccator, evacuated to 10 ⁻² Torr or less, and nitrogen gas replacement for introducing nitrogen to atmospheric pressure was repeated three times, and then stored under the nitrogen atmosphere for 2 hours. The total organic carbon concentration in the vacuum desiccator was 100 μgC / L, and the cleanliness class was ISO class 4.
The surface free energy was evaluated by the Owens-Wendt-Kaelble method from the measurement of the wetting angles of pure water and CH ₂ I ₂ .
The glass material borate glass A of the optical element molding material of this embodiment is an optical glass having a glass transition temperature of 520 ° C., a refractive index of 1.69350 and a linear expansion coefficient of 69 × 10 ⁻⁷ / ° C. is there.

This optical element molding material was set in a molding apparatus. At the time of installation, the environment of the molding material during transportation was 1000 μg C / L in total organic carbon concentration, and the cleanliness class was ISO class 6. Furthermore, the inside of the molding apparatus was 500 μg C / L or less in total organic carbon concentration, and the cleanliness class was ISO class 5. Then, it is heated to 610 ° C. in a nitrogen gas atmosphere and pressurized at a pressure of 150 kg / cm ² for 1 minute. After releasing the pressure, cooling was performed at a cooling rate of −50 ° C./min to 480 ° C., and thereafter, cooling was performed at a rate of −200 ° C./min or more, and the temperature of the press-formed product dropped to 200 ° C. or less. Thereafter, the molded product was taken out. As a molding die, a molding surface of polycrystalline SiC produced by the CVD method was mirror-polished to Rmax = 18 nm, and then, as a release film on the molding surface, using an ion plating method film forming apparatus, A DLC: H film was used.
As a result of continuously pressing a convex meniscus lens having a diameter of 12 mmφ with the same mold and observing the appearance of the optical element up to 2000 times of pressing, it was good.

Comparative Example 1
After the washing, the same type of continuous press was carried out in the same manner as in Example 1 except that it was not cleaned, and was stored in a room having a total organic carbon concentration in the air of 12,000 μg C / L or more for 2 days. In the same manner as in Example 1, a sampling inspection was performed for each washing / storage lot, and the surface free energy was evaluated using the Owens-Wendt-Kaelble method by measuring the wetting angles of pure water and CH ₂ I ₂ . The lowest value of the surface free energy was 42 mJ / m ² , and 28% of the lots had the lowest value of the surface free energy of less than 60 mJ / m ² .
As a result of starting continuous pressing without selecting these optical element molding materials, a fused product considered to be sub-μm size glass was recognized on the surface of the DLC: H release film of the molding die after 650 times. Further, when the press was continued with this mold, cracks were continuously generated in the formed optical element, and it was no longer possible to continue the press. Cracks of the optical element were generated from the fusion part on the surface of the DLC: H release film of the mold, and the release film on the surface of the mold had to be regenerated.

Example 2
After cleaning, the optical element molding material was prepared in the same manner as in Example 1 except that it was not cleaned and stored in a room having a total organic carbon concentration of 8,000 μg C / L in air for 2 days. A sampling inspection was performed for each washing / storage lot in the same manner as in Example 1, and the surface free energy was evaluated using the Owens-Wendt-Kaelble method from the measurement of the wetting angles of pure water and CH ₂ I ₂ . The lowest value of the surface free energy was 45 mJ / m ² , and 19% of the lots had the lowest value of the surface free energy of less than 60 mJ / m ² . Surface minimum free energy except Lot less than 60 mJ / m ^2, the optical element molding material only lots minimum value of the surface free energy is 60 mJ / m ² or more, in the same manner as in Example 1, continuous press did.
As a result of observing the appearance of the optical element up to 2,000 presses by continuous pressing with the same mold, it was good.

Example 3
In the same manner as in Example 2, a film of aC: H having a film thickness of 1 nm was formed by an acetylene gas pyrolysis CVD method only on optical element molding materials of lots having a minimum surface free energy of 60 mJ / m ² or more.
The molding material was stored in the same room as in Example 2 for 2 days, and the environment of the molding material during transportation had a total organic carbon concentration of 500 μg C / L and a cleanliness class of ISO class 6. Further, the total organic carbon concentration in the following CVD apparatus was 2000 μg C / L, and the cleanliness class was ISO class 5.

The CVD method by thermal decomposition of acetylene gas was performed as follows.
The glass material was placed on a quartz tray and placed in a bell jar (reaction vessel). The inside of the bell jar was evacuated to 0.5 torr or less by a vacuum pump, and then heated and maintained at 480 ° C. By exhausting with a vacuum pump while introducing nitrogen gas into the bell jar, the pressure was maintained at 160 torr, and after purging for 30 minutes, the introduction of nitrogen gas was stopped. Further, after the inside of the bell jar was evacuated to 0.5 torr or less by a vacuum pump, acetylene gas was introduced at 40 torr for 20 minutes, and the introduction was stopped. After cooling, the pressure was returned to the atmospheric pressure while diluting with nitrogen gas, and the glass material was taken out.
Thereafter, continuous pressing was performed with the same mold. As a result of observing the appearance of the optical element up to 2000 presses, as shown in Table 3, the appearance quality was good or extremely good.

Comparative Example 2
After cleaning, the optical element molding material produced in the same manner as in Example 1 except that it was not cleaned and was stored for one week in a room having a total organic carbon concentration in the air of 20,000 μg C / L, for each cleaning / storage lot The surface free energy was evaluated using the Owens-Wendt-Kaelble method by measuring the wetting angles of pure water and CH ₂ I ₂ . The lowest value of the surface free energy was 38 mJ / m ² , and 42% of the lots had the lowest value of the surface free energy of less than 60 mJ / m ² . Without selecting these optical element molding materials, a film of aC: H having a thickness of 1 nm was formed by the CVD method in the same manner as in Example 3, and then continuous pressing was started. After 1200 times, a fused product considered to be sub-μm size glass was observed on the surface of the DLC: H release film of the mold. Further, as a result of continuing the press with this mold, cracks were continuously generated in the formed optical element, and it was no longer possible to continue the press. Cracks of the optical element were generated from the fusion part on the surface of the DLC: H release film of the mold, and the release film on the surface of the mold had to be regenerated.

Examples 4 to 11
As in Example 2, for the optical element molding materials of only the lots having a minimum surface free energy of 60 mJ / m ² or more, the surface layers shown in Tables 5 and 6 were formed and then continuously pressed with the same mold. As a result of observing the appearance of the optical element up to 2000 presses, as shown in Tables 5 and 6, the appearance quality was good or extremely good.

FIG. 3 is an explanatory view of a glass material for molding. Explanatory drawing of the glass material for molding which has a surface layer. Explanatory drawing of a self-assembled film. IR-RAS spectrum of self-assembled film FIG. 4 is an explanatory diagram of a self-assembled film composed of a multilayer.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Preformed glass 2 Surface whose surface free energy is 60 mJ / m ² or more 3 Surface layer formed on the surface whose surface free energy is 60 mJ / m ² or more 4 Including starting material of self-assembled film Solution (coating solution)
Reference Signs List 5 Molecule in solution 6 Deposition base material 7 Self-assembled film 8 Self-assembled film molecule 9 Multi-layered self-assembled film 10 Self-assembled film composed of multiple molecular layers 11 Self-assembled film molecule A
12 Self-assembled monolayer B
13 Self-assembled monolayer molecules 1
14 Self-assembled monolayer 2
15 Self-assembled monolayer 3
16 Self-assembled monolayer molecules 4

Claims (5)

A step of heating and softening a glass material which has been preformed, and a step of pressure molding by mold, a method of manufacturing a glass product, the glass material with 60 mJ / m ² or more surface free energy, heat-softened A production process, wherein the production process is followed by a pressure molding process. The glass material that has been preformed, the surface free energy is washed so that 60 mJ / m ² or more, and heat softening step to the start and held in an environment capable of maintaining 60 mJ / m ² or more surface free energy, wherein Item 1. The production method according to Item 1. A step of heating and softening a glass material which has been preformed, and the mold by comprising the step of pressure molding, a method of manufacturing a glass product, the surface layer on the glass material with 60 mJ / m ² or more surface free energy A method for producing a glass product, which comprises subjecting it to a heat softening step and a pressure forming step after being formed. 4. The method according to claim 3, wherein the surface layer is a thin film containing carbon as a main component and having a thickness of 0.1 nm or more and 1 μm or less. The glass material that has been preformed, the surface free energy is washed so that 60 mJ / m ² or more, and up to the formation of a surface layer, held in an environment capable of maintaining 60 mJ / m ² or more surface free energy, The method according to claim 3.

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