JPH09295818A - Mold for molding glass and molding of glass product for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mold for molding glass excellent in mold release and oxidation resistance and hardly subjecting to scratches on the glass surface by using a stainless steel as a substrate body and composing the contact surface with the glass by forming a coating containing a specified component thereon. SOLUTION: This mold for molding glass is composed of a substrate body preferably made of a stainless steel which is a martensitic steel and has a coating formed on a contact surface with the glass and comprising 40-90wt.% Ni and/or Co, 1-40wt.% Cr and a transition element having >=2200 deg.C melting point, preferably one or more elements selected from Ta, Nb, W, Mo, Re, Ru and Ir (e.g. a membrane composed of Ni, Co, Cr, W and Mo). The thickness of the coating is preferably 1-500μ.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass molding die, in particular, a glass molding die used for press-molding glass products such as television cathode ray tube panels and funnels, and a method for molding a cathode ray tube glass product. Regarding

[0002]

2. Description of the Related Art The cathode ray tube of a television is the front (image area)
The panel and funnel-shaped funnel and neck are made separately, and the inner surface of the panel is coated with a phosphor, etc., and the shadow mask and electrodes are attached. Therefore, extremely strict quality control is required for the surface accuracy of the inner surface of the panel and the properties such as surface irregularities. Molded panel above is melted 1,000 ℃
It is made by pressing glass at a high temperature of about 100 ° C with a mold, so the mold used for molding has characteristics such as mechanical strength, heat resistance and chemical stability against high temperature glass. Is required.

As a molding die suitable for such a purpose,
Chromium plating and nickel
Those that have been plated with a tungsten alloy have been used. Since the plating film deteriorates with repeated glass molding, the mold substrate is recycled by peeling off the film and newly plating. However, chrome plating suitable for molds is formed using a Sargent bath, mixed catalyst bath, high efficiency bath, etc. It has drawbacks that it is easily scratched, it is necessary to frequently apply a release agent to the mold surface, and it is extremely weak against halogen.

On the other hand, the nickel-based alloy plating film has excellent releasability from glass, and nickel-tungsten, nickel-phosphorus-tungsten, nickel-boron-tungsten, etc., are used to form a film containing tungsten in nickel. Alloy plating that ensures hardness has been developed. For example, nickel-tungsten alloy plating has advantages such as being able to form a film under conditions where toxicity and odor of chemicals do not pose a problem, reducing the frequency of use of a release agent, and preventing scratches on the glass surface. In recent years, it has been said that the proportion of glass used as a film for glass molding dies is increasing.

[0005]

However, since the tungsten contained in the nickel alloy coating containing tungsten is easily oxidized and the coating is rapidly oxidized, when it is used as the surface coating of the panel molding die, chromium is not used. It had a drawback that the life was extremely short compared to the plating film. Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to use it in press molding of molds useful for glass molding such as cathode ray tube panels, particularly glass products such as television cathode ray tube panels and funnels. The present invention provides a glass molding die and a method for molding a glass product for a cathode ray tube.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a glass molding die characterized in that a stainless steel substrate is used, and a coating film containing the following components is formed on the glass contact surface thereof. (1) 40 to 90% by weight of nickel and / or cobalt as the A component, and (2) 1 to 4 of chromium as the B component.
0% by weight and (3) C component having a melting point of 2,200 ° C.
3 to 55% by weight of the above transition elements

[0007] The deterioration of the mold for glass molding is about 100
It is considered that this is due to the oxidation and mechanical deformation of the surface film due to the molding of glass at a high temperature near 0 ° C. That is, this oxidation process consists of corrosion by air before and after contact with glass, so-called high temperature oxidation, and mechanochemical reaction with molten salt called molten glass in the panel molding process.

In order to suppress the deterioration of the glass molding die, it is important to ensure the chemical and mechanical stability of the film on the glass contact surface of the die, and conventional chromium plating is extremely chemical. The heat resistance is obtained by the generation of chromium oxide which is stable and mechanically dense. When the protection of the oxide film of the film on the glass contact surface is weak, oxygen in the atmosphere diffuses and permeates into the metal film through the oxide film layer, and the deterioration of the mold progresses. At the glass melting temperature, the metal atoms in the metal lattice are in a temperature range where movement of metal atoms is active, and the iron contained in the stainless steel that is the metal substrate diffuses toward the surface.

The inventors of the present invention have conducted earnest research on a glass molding die which uses a mold releasing agent less frequently on the die surface, is less likely to cause scratches on the glass surface, and is excellent in oxidation resistance. Nickel and / or cobalt as the component A is 40 to 40 in the film on the glass contact surface of the steel substrate.
A glass molding die formed by forming a film containing 90% by weight, 1 to 40% by weight of chromium as a B component, and 3 to 55% by weight of a transition element having a melting point of 2,200 ° C. or higher as a C component, It has much higher oxidation resistance than conventional ones, and therefore has an extremely long service life. It also has excellent glass releasability as a characteristic of the nickel and / or cobalt alloy coating, and scratches do not easily occur on the molded glass surface. I also found that it also has characteristics.

Forming a film made of nickel and / or cobalt as the component A, chromium as the component B, and a transition element having a melting point of 2,200 ° C. or more as the component C on the glass contact surface of the mold. The mechanism for improving the oxidation resistance and mechanical strength of the obtained mold is not always clear, but by adding these elements,
It is considered that it is easy to form a dense oxide film, the movement of elements in the film is suppressed, and the mechanical properties and thermal conductivity properties become suitable for glass molding dies. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to embodiments. The glass molding die of the present invention is made of stainless steel as a base material, and on the glass contact surface thereof, (1) nickel and / or cobalt as component A is 40 to 90.
% Of chromium, (2) B component is 1 to 40% by weight of chromium, and (3) C component is an alloy film containing 3 to 55% by weight of a transition element having a melting point of 2,200 ° C. or higher. It has a feature.

In the present invention, when the component A is less than the above range among the elements constituting the film on the glass contact surface, the shape is maintained as a matrix of the film that can be practically used, and good molding characteristics are obtained. It is insufficient in terms of mechanical properties such as strength and ductility to be developed. On the other hand, when it exceeds the above range, it is insufficient in securing oxidation resistance in high temperature use. Further, if the content of the component B is less than the above range, it is insufficient to secure the oxidation resistance in high temperature use, while if it exceeds the above range, the shape of the coating is maintained substantially as a usable matrix. However, it is insufficient in terms of mechanical properties such as strength and ductility for exhibiting good molding characteristics. Further, when the content of the C component is less than the above range, it is insufficient to secure the oxidation resistance at high temperature use, while when it exceeds the above range, the shape of the matrix of the practically usable film is formed. It is insufficient in terms of mechanical properties such as strength and ductility to maintain and develop good molding characteristics. In the present invention, martensitic stainless steel is preferable as the base of the mold in terms of mechanical strength, corrosion resistance, thermal conductivity and thermal expansion characteristics.

Further, in the present invention, the film on the glass contact surface formed on the mold made of the substrate is formed by plating or CV.
It can be produced by any method selected from the D method, the PVD method and the thermal spraying method. Among these thin film forming methods, the plating method has a high thin film forming speed,
And it is easy to obtain a smooth coating surface along the mold base,
In addition, it is a relatively low cost and is a thin film forming method particularly suitable for achieving the object of the present invention. The thickness of the coating on the glass contact surface is preferably 1 to 500 μm, and if it is thinner than 1 μm, it is inconvenient in that it is easily subjected to high temperature oxidation or mechanical deformation. If the coating is thicker than 500 μm, the coating is It is not preferable in that it takes a long time to form and exceeds the technically and cost effective range.

In order to secure the properties of the nickel and / or cobalt alloy, the film constituting the film on the glass contact surface of the mold contains 40 to 90% by weight of nickel and / or cobalt as the component A and component B. As chrome is 1
-40% by weight, and the C component preferably has 3 to 55% by weight of a transition element having a melting point of 2,200 ° C or higher. The amount of chromium is more preferably 10 to 40% by weight in order to secure the strength and oxidation resistance of the film. A transition element selected from tantalum, niobium, tungsten, molybdenum, rhenium, ruthenium and iridium having a melting point of 2,200 ° C. or more of the C component imparts oxidation resistance to the alloy film and has a function of ensuring strength of the film. The concentration of these is more preferably 10 to 55% by weight.

That is, nickel and / or as the A component
Alternatively, a film made of cobalt, chromium as the B component, and a transition element having a melting point of 2,200 ° C. or more as the C component, while maintaining the good molding characteristics characteristic of the nickel and / or cobalt-based film or Oxidation resistance higher than that is obtained, and a mold having an extremely long life can be obtained, which is preferable.

Further, when forming the film on the glass contact surface on the surface of the stainless steel substrate, it is preliminarily selected from the groups 8, 9, 10 and 11 between the substrate and the film on the glass contact surface. It is preferable to have an intermediate film (thin film) containing at least one element as a main component. The intermediate film is produced by any method selected from a plating method, a CVD method, a PVD method and a thermal spraying method. By forming such an intermediate film, the bond between the mold substrate and the film on the glass contact surface is strengthened, and the alloy film on the glass contact surface can be easily produced. For example,
Nickel, cobalt, iron, palladium, copper, or the like is formed by a thin film forming method such as plating, CVD, PVD, or thermal spraying. In particular, the plating method is suitable in terms of the film forming rate of the intermediate film, smoothness, and cost.

The above-mentioned intermediate film-forming elements are preferably contained in the formed intermediate film in a proportion of 40 to 100% by weight as a main component in order to utilize the characteristics of these elements. The thickness of the formed intermediate film is 0.1 to 50 μm.
m is preferred. If the thickness is less than 0.1 μm, it is difficult to effectively cover the entire surface of the mold, and if it is greater than 50 μm, residual strain increases in the intermediate film formed, resulting in intermediate It is not preferable because the meaning as a film is lost.

Next, the outline of the formation of the intermediate film and the surface layer in the present invention will be described by taking a plating method as a typical example, but the present invention is not limited to the plating method. As the pretreatment of the mold, the following series of steps were performed. A mold, which has been surface-finished to a specified size in advance, is pre-cleaned by alkaline degreasing using a sodium hydroxide (mainly) bath, washed with water, and then subjected to anodic electrolytic cleaning in the same alkaline bath. After the main cleaning by the above, and after rinsing with water, an activation treatment for obtaining a clean surface was carried out by rinsing with an acid soaked water using a hydrochloric acid (mainly contained) bath. (1) Intermediate film Example of composition of plating bath: A nickel chloride bath was used for forming the intermediate film. Nickel chloride 240 g / l Hydrochloric acid 125 mg / l pH: -0.5 Plating temperature: Room temperature Anode: Nickel Load current density: 10 A / dm ²

(2) Coating on glass contact surface One example of composition of plating bath: nickel sulfate 48 g / l cobalt sulfate 5 g / l chromium chloride 53 g / l sodium tungstate 20 g / l sodium molybdate 4.8 g / l Citric acid 55 g / l Boric acid 25 g / l Glycine 42 g / l Ammonia 53 ml / l pH: 2.5 Plating temperature: 30 ° C. Anode: Nickel Load current density: 10 A / dm ²

The present invention also provides a glass for cathode ray tubes containing silicon oxide, sodium oxide, potassium oxide, strontium oxide, barium oxide, or a glass for cathode ray tubes containing silicon oxide, sodium oxide, potassium oxide and lead oxide. Provided is a method for molding a glass product for a cathode ray tube, which is molded using the glass molding die of the invention. When the glass for CRT is molded by using the glass molding die of the present invention, a glass product for CRT such as a panel having excellent surface releasability such as surface accuracy and surface irregularity and a funnel is obtained. It is preferable because it is possible.

Next, an outline of the method for molding a glass product for cathode ray tubes according to the present invention will be described. Cut out a predetermined weight molten glass gob composed of the above components using a blade made of a heat-resistant material,
After placing on a female mold made of heat-resistant alloy that has been subjected to chrome plating or surface treatment according to the present invention, the male mold is pressed with a molding pattern of a predetermined pressure, speed and holding time using hydraulic pressure, and the predetermined size and Mold the shape. Then, after cooling until the shape can be maintained by itself, it is placed in an annealing furnace for removing the stress accumulated inside the glass during the cooling process.

[0022]

EXAMPLES Detailed examples of the present invention are shown below, but the present invention is not necessarily limited to these. Example 1 On the surface of a SUS420J2 (JISG4303) substrate,
A nickel layer having a thickness of 4 μm was deposited using a nickel chloride bath. Then, a nickel-plating bath containing nickel sulfate, cobalt sulfate, chromium chloride, sodium tungstate, sodium molybdate, citric acid, formic acid, boric acid, glycine and ammonia as its main components is used.
A 22 μm-thick glass contact surface film made of cobalt-chromium-tungsten-molybdenum (weight ratio 46: 5: 14: 30: 5) was formed. Vickers hardness, Taber abrasion test, and oxidation increase measurement in air were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

Example 2 On the surface of a SUS420J2 (JISG4303) substrate,
A nickel layer having a thickness of 3 μm was deposited using a nickel chloride bath. Then, a plating bath containing cobalt sulfate, sodium tungstate, chromium chloride, tartaric acid, formic acid, boric acid, and glutamic acid as its main components was used to form cobalt-tungsten-chromium (weight ratio 86: 5: 9) to a thickness of 20 μm. Was formed on the glass contact surface.
Vickers hardness, Taber abrasion test, and oxidation increase measurement in air were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

Example 3 A cobalt layer having a thickness of 5 μm was deposited on the surface of a SUS420J2 substrate using a cobalt chloride bath. Then, a nickel-chromium-molybdenum-ruthenium (weight ratio: 76: by weight) plating bath containing nickel sulfate, sodium molybdate, chromium chloride, ruthenium chloride, sodium citrate, formic acid, boric acid, alanine and ammonia as its main components is used. 12: 9: 3) was formed on the glass contact surface with a thickness of 20 μm. Vickers hardness, Taber abrasion test, and oxidation increase measurement in air were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

Example 4 A nickel layer having a thickness of 2.5 μm was deposited on the surface of a SUS420J2 substrate using a nickel chloride bath. After that, a nickel-plating bath containing nickel sulfate, chromium chloride, potassium perrhenate, potassium citrate, formic acid, boric acid, glycine and ammonia as its main components is used.
A 15 μm thick glass contact surface coating made of chromium-rhenium (58: 31: 9 by weight) was formed. Vickers hardness, Taber abrasion test, and oxidation increase measurement in air were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. Table 1 shows the results
Shown in

Example 5 After depositing a nickel intermediate film having a thickness of 1 μm on a surface of a SUS420J2 substrate with a sputtering apparatus having three targets of nickel, chromium and tantalum, nickel-chromium-tantalum (45: weight ratio). 35:20) to form a film on the glass contact surface having a thickness of 15 μm.
Vickers hardness, Taber abrasion test, and oxidation increase measurement in air were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

Example 6 A 3 μm thick palladium layer was deposited on the surface of a SUS420J2 substrate using a tetraaminopalladium bromide bath. Then, a film of a glass contact surface made of nickel-tungsten-niobium (weight ratio 57:24:19) having a thickness of 18 μm was formed by a thermal spraying method using fine powders of nickel, chromium and niobium as raw materials. About this film,
Vickers hardness, Taber abrasion test and oxidation increase in air were measured, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

Example 7 A nickel layer having a thickness of 3.5 μm was deposited on the surface of a SUS420J2 substrate using a nickel chloride bath. Then, a nickel-palladium layer was deposited using an ammonia alkaline electroless plating bath containing palladium chloride as a reducing agent using hypophosphorous acid. Thereafter, a plating bath containing cobalt sulfate, chromium chloride, sodium tungstate, iridium chloride, sodium citrate, formic acid, boric acid, and glycine as its main components was used to form cobalt-chromium-tungsten-iridium (80:10:18 by weight). : 2) was formed on the glass contact surface having a thickness of 15 μm. Vickers hardness, Taber abrasion test, and oxidation increase measurement in air were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

In Examples 1 to 4, 62.0% by weight of silicon oxide, 7.5% by weight of sodium oxide, and 8.1% by weight of potassium oxide were used as glass for cathode ray tube panels.
Strontium oxide 11.6% by weight, barium oxide 2.
Glass for cathode ray tubes containing 2% by weight and 8.6% by weight of zirconium oxide and the like was used. Moreover, Examples 5 to 7
For, regarding silicon oxide 64.6% by weight, sodium oxide 6.0% by weight, potassium oxide 2.5% by weight, lead oxide 3.0% by weight, and other strontium oxide 23.9%.
CRT glass containing 10% by weight was used.

Comparative Example 1 A 16 μm thick glass contact surface film was formed on the surface of a SUS420J2 substrate using a chromium sulfate bath. Vickers hardness, Taber abrasion test, and oxidation increase measurement in air were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

Comparative Example 2 A nickel layer having a thickness of 6 μm was deposited on the surface of a SUS420J2 substrate using a nickel chloride bath. After that, a plating bath containing nickel sulfate, sodium tungstate, and potassium citrate as its main components was used to form a nickel-tungsten (weight ratio of 71:29) layer having a thickness of 20 μm.
A film of the glass contact surface of m was formed. Vickers hardness, Taber abrasion test, and oxidation increase measurement in air were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

In Comparative Examples 1 and 2, the same glass as in Examples 1 to 4 was used as the glass for the cathode ray tube panel.
Clarified the difference in effect depending on the mold. In Table 1, the Taber index, the amount of oxidation increase, and the panel molding characteristics are shown as relative values when Comparative Example 1 was set to 10.

[0033]

[Table 1]

[0034]

According to the present invention, as shown in the above embodiment, nickel and / or cobalt as the component A, and B as the component A in the coating on the glass contact surface of stainless steel as the structural substrate.
By forming a film containing chromium as a component and a transition element having a melting point of 2200 ° C. or more as a C component, it is superior to the conventional chromium film in releasing property, less likely to cause scratches on the glass surface, and moreover nickel-tungsten film. It has an effect of far superior oxidation resistance.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoki Yoshida 1150 Hazawacho, Kanagawa-ku, Yokohama-shi, Kanagawa-ken, Central Research Laboratory of Asahi Glass Co., Ltd.

Claims (8)

[Claims] 1. A mold for glass molding, comprising a stainless steel substrate, and a glass-contacting surface having a film containing the following components formed thereon. (1) 40 to 90% by weight of nickel and / or cobalt as the A component, and (2) 1 to 4 of chromium as the B component.
0% by weight and (3) C component having a melting point of 2,200 ° C.
3 to 55% by weight of the above transition elements 2. The mold for glass molding according to claim 1, wherein the C component is at least one element selected from the group consisting of tantalum, niobium, tungsten, molybdenum, rhenium, ruthenium and iridium. 3. The thickness of the film on the glass contact surface is 1 to 500 μm.
The mold for glass molding according to claim 1, wherein m is m. 4. An intermediate film containing, as a main component, at least one element selected from the group 8, 9, 10 and 11 between the stainless steel substrate and the film on the glass contact surface. Item 1. A mold for glass molding according to Item 1. 5. The mold for glass molding according to claim 4, wherein the thickness of the intermediate film is 0.1 to 50 μm. 6. The glass molding die according to claim 1, wherein the stainless steel substrate is a martensitic steel. 7. Molding glass for cathode ray tubes containing silicon oxide, sodium oxide, potassium oxide, strontium oxide and barium oxide using the glass molding die according to any one of claims 1 to 6. A method for forming a glass product for a cathode ray tube, characterized by: 8. A glass for a cathode ray tube containing silicon oxide, sodium oxide, potassium oxide and lead oxide,
7. A method for molding a glass product for a cathode ray tube, which comprises molding using the glass molding die according to any one of items 1 to 6.