TW546263B - Treatment of vitreous material - Google Patents

Abstract

A sheet of vitreous material for use as a substrate is produced by subjecting the sheet to chemical tempering with a molten alkali metal salt prior to any firing step or other heat treatment associated with the application of coating layers. The so-treated sheet has improved dimensional stability, such that wide ranges of heating and cooling applied by the heat treatment do not create an unacceptable amount of shrinkage of the vitreous material.

Description

546263

5. Description of the invention (1) The present invention relates to the treatment of a thin sheet of transparent material such as glass, and the sheet formed therefrom. In particular, it relates to the manufacture of transparent material sheets having improved dimensional stability. Because glass and similar transparent materials are amorphous, processing through heating and cooling can cause dimensional changes, such as reduced area. This reduction, which is also known as tightening or shrinking, is irrelevant for many purposes. However, the demand for improvement in the dimensional stability of glass has increased. For example, glass sheets used as substrates for sub-applications. In these applications, because of the need for precise calibration of the glass 2 composition1, even very small shrinkages have been made in the past and many plans have been made to provide a thermal history of the glass that tends to continue during processing. This glass is effective to accept: so it is realized to reduce the inclination of shrinkage during the necessary heat treatment: shrinkage tempering is a well-known method of densification, but it includes extended treatment, which requires substantial input of thermal energy, and the result: quality at temperature . The degree of densification will vary with tempering temperature and door: 丄 unevenness. Other difficulties are that the viscosity of the glass will increase at a higher rate and the sheet will deform or form during the tempering process: the defect is low, such as σ, the solution is selected from a glass composition with a very high flex point j, which can be ignored during the process Its shrinking. A special problem occurs when the glass substrate is thinner than A at a temperature of more than 5 00 t, which is higher than the soda-stone processing step. This untreated soda -The linear size of the lime glass flakes in cold tempering, for example 600 micrometers / meter 彳 smaller than the starting flakes. Has smaller

546263 V. Description of the invention (2) The object of the present invention is to provide a simple and reliable method for improving the thermal stability of transparent materials, which will reduce the dimensional shrinkage during heat treatment. The chemical tempering of transparent materials is well known. The purpose is to grant Suiming materials such as glass and glass-like crystal materials to increase machinery ^ ^: There are two types of tempering. One type of process; = complete ion exchange under high pulse and stress occurs in the glass, while the ions entering the trip can grant a lower thermal expansion coefficiency of the glass surface. Another type of process is to replace the ions in the surface of the glass with larger ions, and this ionization can be achieved at the tempering temperature of the glass, so the stress release of # degrees will not occur. 276186 teaches that the chemical tempering treatment of transparent bodies can allow at least ions to enter the surface layer of the body, and then apply a coating such as a bowl, a pot or other metal oxide, titanium nitride, or Shi Xi, titanium, dream, its metal Carbides. The chemical examples of chemically tempered acid sodium and carbonic acid bellows include potassium, and steps: or to form a coating on the sheet (this book Η i ^) to reduce the degree of shrinkage of the transparent sheet. The cymbal is connected with double imagination and is 4 ^ efficient. …, Then contact with the molten alkali metal salt to obtain the product = this: 征 iJ-supply-a kind of transparent material as a substrate for the production of other related processing: the winding step or the coating of the sheet Daddy #… the processing cuts it into contact with the molten alkali metal salt.

546263 V. Description of the invention (3) The method of the method is that the alkali metal ions from the molten salt diffuse into the surface layer and the ions from the surface layer diffuse into the molten salt. The ion exchange produced can generate or increase the surface layer. Shrinking stress. The original f was expected to find that, in addition to other effects on the transparent sheet, this chemical =, can be modified ^ its dimensional stability, so the extensive application of the f cold part target circumference due to heat treatment will not produce unacceptable Amount of contraction. It is not expected that after heat treatment at a temperature higher than the tempering point of the transparent material such as firing = for example 580 C, the full force induced by ion exchange on the surface of the sheet will disappear and the transparent material will lose its obtained from the chemical tempering strength~. The resulting flakes also have better dimensional stability and uniformity than flakes that are individually tempered. The present invention therefore provides a thin sheet of transparent material with thinning accuracy. The reasons for the effectiveness of the chemical tempering on thermal dimensional stability are not complete with the two-part gauge: Qiu: Due to the excellent thermal contact between the molten salt and the surface of the sheet and partly because of the ions between the salt and the sheet exchange. Traditionally soda-lime glass and, if necessary, the method of the present invention can also be used for oxalate, Is silicate, and glassy. However, the present invention can be typically applied at the beginning of the description and also about this type, if it is necessary to use it Type of glass, such as code crystal material. The choice of chemical tempering salt depends on factors such as the specific talents of the Ming materials. Common metals or molten salts selected from lithium and potassium metals can be used. Molten potassium nitrate is particularly suitable for soda-lime glass. This sheet can be conveniently immersed in salt in a suitable container to achieve contact between the sheet and the molten salt.

C: \ ProgramFiles \ Patent \ 54945.ptd page 6.

546263

This transparent material ^ 7 ,, w # Adjust carefully. The wire should pass through the stage of the method of the present invention. The temperature of the small material is preferably two or more degrees to maintain its state of fusion. The "min" of this transparent material at the temperature of ?? Λ molten salt, the best rate is less than that of vulgar molten salt. Soaking for a period of time, tempering can ensure transparency, including the period of &#; Degree required. The temperature of the family Lumenaceae rises i, and is maintained at ⑤ The molten salt temperature is typically maintained for 15 minutes to 72 hours compared to the contact between the salts, and it should be at Hi. For molten potassium and other larger ions, this molten salt is ^ Α〇η ^ ςηπ 〇λ. ^ Personal point, below the degree of insolation 'and its typical temperature range 搲 ^ _M # β. It is important to keep the temperature throughout the tank and throughout the immersion period. The temperature of the molten salt preferably has a maximum deviation of ^ \ n. Blow carbon monoxide through the salt to achieve mixing. Conditions are taught, for example, in earlier patent 2,473. After removal from the molten salt, the transparent material should slowly cool from the salt temperature, preferably at a rate of less than 15 t / min. Slow cooling rates have been shown to avoid structural damage to the transparent material and promote low levels of shrinkage. In some cases, 'can be excellently cooled in two stages, each stage having a different cooling rate. The invention is further described with reference to the following non-limiting examples. These used glass sample slices were cut to a nominal size of 35 × 270 mm. The sheet thickness of Examples 1 to 5 was 11 mm and the sheet thickness of Examples 6 and 7 was 3 mm. The samples of Examples 1 to 5 were kept in a warm cabin at 2000 ° C until they were processed as described below.

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V. Description of the invention (5) Each sample port is processed and a different system order $, Q, n ^ ^., ^ J 幻 表 向 U # Also measured the length of this 350 ¾ correctly, All with sound: the length of the eye 丨 θ ^ 丨, then ϊ is made 0 at a ambient temperature of 20 ° C. Example 1 The sample flakes of soda lime floating glass are placed in the carrier at 2000t and the heat has been stably heated. The preheating of the h6 (rc) grabs the super sword for 30 hours and 30 minutes. The heating rate is about 3 minutes. The glass and the carrier are then placed at a temperature of 460 t, and the saccharine towel is melted and kept for four hours for ionization. Exchange. The glass and carrier are then placed in the tank for 30 minutes, during which most of the molten acid Y is removed from the tank and the glass and carrier are discharged for collection and reuse. The glass sample is then placed in the cooling chamber slowly Ground cooling, first at a rate of about 1 C / minute for 2 hours, and second at a rate of about 2 ° c / minute for J hours i 5 minutes. After the processing procedure as described above, the calibrated 35 mm size of each sample sheet Correctly again at 2 (TC measured and compared with the graph obtained before processing 'in order to measure Determine the degree of shrinkage caused by the treatment. The results shown in the attached table are the average graphs of all twelve samples. Example 2 A batch of ten samples of ordinary soda lime floating glass was placed in a carrier at 2000 °. Neutralize the general treatment as described in Example 1, but the difference is that the carrier is directly placed in a molten potassium nitrate tank, and the step of preheating to a tank temperature of 460 ° C is omitted. Therefore, the glass is heated more quickly to Bath temperature, it is estimated that the temperature increase rate is about 50 ° C / min.

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After the processing procedure was completed, each dimension was measured again correctly at 20 ° C to show the degree of shrinkage. This average result is shown in the attached table for the calibrated 350 mm of the sample sheet of Example 3 and the figure obtained before processing. The seven sample flakes treated according to Example 1 were subjected to a process including heating from a peripheral temperature of 20: a rate of 5 ° C / min to 46 0 t, maintaining at this temperature for 30 minutes, and then slowly cooling to a peripheral temperature after autumn ( A). Calibrated at 350 millimeters, the size is measured twice and compared with the figure obtained before processing (A). This person

The average shrinkage is shown in the table. T Example 4 The five sample flakes processed according to Example 1 included heating from a weekly temperature of 20 ° C to 3 ° C / min to 46 ° C, that is, a lower rate than the treatment (phantom, hold, temperature for 30 minutes and then slower). Cooled slowly to ambient temperature (β). This calibrated 350¾ meter size was again measured correctly at 20 and compared to the graph obtained at 4). This average shrinkage is shown in the table. Example 5 Comparative sample flakes of ordinary soda-lime floating glass 20 were subjected to a simple heat treatment 'without contact with any potassium nitrate or other chemical tempering agents. This treatment included removing the sample from 2 at a rate of 3 t / min. 〇It is heated to 46 ° C 'Keep this temperature at this level for 30 minutes and slowly cool down to 2 ° C. This shrinkage is measured again and this average graph' is shown in the table, compared to the samples that received chemical tempering and heat treatment The measurement is twice as much. The sample sheet prepared according to Example 3 has a particularly excellent shrinkage due to high temperature processing of less than 1000 microns / meter.

C: \ Program Files \ Patent \ 54945.ptd 546263 V. Description of the invention (7) Examples 6 and 7 Examples 6 and 7 perform chemical tempering of glass in molten potassium nitrate in a typical industrial unit. This unit includes a preheating tank, a molten potassium nitrate tank, a discharge tank, a cooling tank and a washing station. The samples used in Example 6 were Jintong's soda-lime floating glass, whereas those in Example 7 were particularly clear glasses (with very low iron content). The samples (20 in Example 6 and 10 in Example 7) were placed in the carrier and put into the preheating chamber, and the temperature was increased at a rate of about 1 (rc / minute to 400), which is close to melting. The working temperature of potassium nitrate. The carrier is then placed in a molten potassium nitrate tank and left to soak for eight hours. The push rod gradually advances the carrier through the molten salt tank to the discharge tank over the period. The melting throughout this period The temperature of potassium nitrate is maintained within 465 and 2. The continuous generation of bubbles of carbon dioxide gas passes through this tank, which is used to promote mild agitation of ions, mix the salt, and help maintain the volume throughout the molten salt. The temperature of the segment i: trough :: dagger! The sample is discharged in a few minutes and then the second-order two-second rate is "c / minute to 22o ... and then at a rate of 5 C / minute or less to week Temperature 2 0. After bran: 杳 冰 * ,,,, but the sample.…, After / month / first, dry without, and the measurement of the cold and the average shrinkage are shown in the table. The shrinkage results in the respective examples The time is quite equal, within every 10% of all examples. This It has better uniformity than that obtained by the tempering procedure. The high I obtained after the tempering process is reduced here. Accept the changed size that can be ignored in the certificate ...

546263 V. Description of Invention (8) Table

The processing of transparent material sheets according to the invention is particularly useful in the manufacture of display panels, as described in the patent application nG 9 7 11815 filed in the French application, by Thoms on Tubes Electro niques under the heading " Procgde de realisation d 'unpanneau de visualisation comport ant une dalle a stability dimensionelle am [lier [e.g., a method for manufacturing a sheet for improving dimensional stability that can be used for display panels "] on September 23, 1997.

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Claims (1)

546263 _Case No. 87115502_ 年月 日 _ ^ _ VI. Scope of Patent Application 1 1. As for the method of applying for the scope of patent application No. 10, the transparent material is cooled in two stages, each stage has a different cooling rate. 54945-920516.ptc Page 14 Announcement η 87115502 t >, f Revision VI. Patent Application Scope 1. A transparent feature that can be used as a substrate is made at any firing step or with other coatings. Before the heat treatment, it diffuses into the molten salt with the molten lithium or potassium salt ions of the molten salt into the flakes, which increases the compressive stress in the surface layer. 2. The method as described in item 1 of the patent application potassium. 3. If you apply for the item 1 or 2 of the patent scope, the contact will be maintained for a period of 15 minutes to 72 hours. 4. The method for applying for item 3 of the patent scope is for a period of 4 to 8 hours. 5. If the scope of the patent application item 1 or 2 is maintained in the temperature range of 400 to 500 ° C. 6. If you apply for item 1 or 2 of the patent scope, keep it at a uniform temperature with a maximum deviation of 2 ° C. 7. If you apply for item 1 or 2 of the patent scope, slowly raise the temperature towards the molten salt. 8. If the method of applying for item 7 in the scope of patent application: is to increase at a rate lower than 15 ° C / minute. 9. If the party applying for item 1 or 2 of the patent scope contacts, slowly cool the transparent material to 10. For the method applying for item 9 of the patent scope, cool at a rate below 15 ° C / min. A method of applying a thin sheet of material to the contact of the potassium salt with the thin sheet, in which ion exchange from the molten surface layer and from the surface layer will generate or 'The method of contacting with molten salt is the method of making molten salt, which is the method of making molten salt, which is the temperature method of making transparent materials into transparent materials, which is the temperature of the environment with molten salt. ‘Where the transparent material is 54945-920516.ptc Page 13