Manufacturing system for manufacturing high-refractive-index glass beads and method for manufacturing high-refractive-index glass beads using same

Abstract

The present invention relates to a manufacturing system, which is used for manufacturing single body-type glass beads having a high refractive index and a large diameter, and a method for manufacturing high-refractive-index glass beads using same. More specifically, the present invention relates to a manufacturing system for manufacturing high-refractive-index glass beads, and a method for manufacturing high-refractive-index glass beads using the manufacturing system, the manufacturing system comprising: a skull melting furnace for melting a glass composition having a high refractive index; a skull fining furnace for stabilizing the molten glass composition from the skull melting furnace and adjusting the temperature to form a molten flow of the glass composition; a cutting device for cutting the molten flow of the glass composition into cut bodies; and a cooling tank for cooling the cut bodies.

Description

Manufacturing system for manufacturing high-refractive-index glass beads and method for manufacturing high-refractive-index glass beads using the same

[0001] The present invention relates to a manufacturing system used to produce glass beads having a high refractive index and a large diameter, and a method for producing high refractive index glass beads using the same. In particular, the invention relates to a manufacturing system for producing glass beads having a refractive index of about 1.9 or higher and a diameter of about 0.4 to 1.2Ø, a method for producing said glass beads using said manufacturing system, and glass beads produced using said manufacturing method.

[0002] The glass beads according to the present invention have a high refractive index and a large diameter, so they can be directly used in retroreflective paints for road signs or lane markings.

[0003]

[0004] Recently, as market demand for autonomous vehicles has increased, related research and development is actively underway.

[0005] For autonomous vehicles to operate safely and efficiently, technological advancements such as high-precision maps, sensor fusion technology, and AI-based decision-making systems are essential. In particular, accurately perceiving the vehicle's surroundings in real time and determining the optimal driving path is crucial; to achieve this, data processing technologies utilizing various sensors, including LiDAR, radar, and cameras, are continuously evolving.

[0006] Meanwhile, lane recognition in autonomous vehicles is achieved by analyzing the color of the lanes and the contrast of the road surface. Therefore, for a vehicle to perform autonomous driving reliably, it is essential not only to enhance the overall performance of the driving system but also to improve reflectivity so that lanes and road signs can be clearly identified even in adverse environments such as night or bad weather.

[0007] For road signs and lanes to be accurately recognized by autonomous driving system cameras, they must possess high retroreflective performance. Retroreflectivity refers to the property of reflecting light back in the direction of incidence, and it is primarily applied to road signs and road surfaces to improve visibility and enhance driver safety. In other words, the better the retroreflectivity, the more incident light is reflected back in the direction of the original angle of incidence. While this characteristic is determined by various factors such as the physical properties of the surface, material composition, refractive index, and transparency, the most important characteristic is the refractive index.

[0008] The development of retroreflective materials has primarily focused on silicon-based materials, which are cost-competitive and have excellent optical properties. Their forms have also evolved in various ways, such as bead, prism, planar, and composite types, but currently, the most widely used method is to apply high-refractive-index glass beads with excellent retroreflective performance to road markings.

[0009] In the prior art, Registered Patent Publication No. 10-2503346 (published on February 24, 2023) discloses a retroreflective component comprising a core; a plurality of glass or glass ceramic beads adjacent to the core; and a plurality of particles adjacent to the core, wherein each of the particles has a diameter smaller than the average diameter of the glass or glass ceramic beads, the retroreflective component has an average diameter of 100 micrometers to 2000 micrometers, the glass or glass ceramic beads have an average diameter of 60 micrometers to 80 micrometers, and the particles have a diameter of 1 nanometer to 60 micrometers.

[0010] Although the aforementioned retroreflective component exhibits the effect of preventing a decrease in retroreflectivity even when the liquid road surface marking component of the road marking composition wicks or covers all or a significant portion of the retroreflective component, it has the problem that the retroreflective performance rapidly deteriorates because the glass or glass-ceramic beads, which play the most important role in retroreflectivity, exist merely attached to the core and easily detach from the core due to wear caused by vehicle driving, and it also has the disadvantage of a complex manufacturing method. Furthermore, since the aforementioned retroreflective component includes a core and glass or glass-ceramic beads coated on top thereof, the number of interfaces where refraction occurs with respect to incident light increases accordingly, which leads to the problem of increased light loss due to diffusion, reflection, etc.

[0011] In addition, Registered Patent Publication No. 10-0773438 (published Nov. 05, 2007) comprises a first step of forming a resin layer on the upper surface of a polyester polymer film (10); a second step of evenly coating glass beads (20) by a mechanical method using a press roller (32) and a support roller (34) located above and below the transparent polymer film (10), while simultaneously settling only half of the diameter of the glass beads (20) into the coated resin layers; a third step of depositing an aluminum vacuum deposition film (40) on the glass beads (20) in a state where only half is settled and the upper half is exposed to increase the retroreflective brightness; and a fourth step of separating the glass beads, on which only half has the aluminum vacuum deposition film (40) formed, from the polymer film (10) using a glass bead separation (separation) roller (60) located above the polymer film (10). A method for manufacturing retroreflective glass beads characterized by the following is disclosed.

[0012] However, the above method can only be applied to the production of microspheres with a diameter of 55 to 65 μm, and is not suitable for the production of glass beads with a large diameter of 0.4 Ø or more, and has limitations in that it does not take into account the refractive index of the glass beads themselves.

[0013] Therefore, there is a need for the development of an integrated glass bead that possesses a high refractive index and excellent retroreflectivity, has a large diameter so that it is not easily lost due to wear, maintains its high refractive index even upon wear, and minimizes light loss.

[0014] However, glass compositions with a high refractive index have a very high melting point and high specific gravity, so it is not possible to manufacture integrated glass beads with a large diameter using the conventional floating glass bead manufacturing method using a gas burner.

[0015] Therefore, to date, no method has been reported for manufacturing glass beads with a high refractive index as a single unit with a large diameter.

[0016]

[0017] The present invention aims to solve the problems described above by providing a manufacturing system for producing an integral glass bead having a high refractive index of about 1.9 or higher and a diameter of about 0.4 to 1.2Ø, and a method for producing a glass bead using said manufacturing system.

[0018]

[0019] The present invention provides a manufacturing system for producing high-refractive-index glass beads comprising: a skull melting furnace for melting a glass composition having a high refractive index; a skull clarification furnace for stabilizing the molten glass composition melted from the skull melting furnace and controlling the temperature to form a molten flow of the glass composition; a cutting device for cutting the molten flow of the glass composition into a cutting body; and a cooling tank for cooling the cutting body.

[0020] In the manufacturing system for manufacturing high refractive index glass beads of the present invention, the skull clarification furnace comprises a skull clarification furnace body, a high-frequency induction coil, and a nozzle, wherein the nozzle comprises an opening with a diameter of approximately 0.8 to 2.4Ø, and the nozzle may be composed of a platinum-rhodium alloy.

[0021] In the manufacturing system for manufacturing high refractive index glass beads of the present invention, the skull clarification furnace can be set to a temperature of about 1,800 to 2,000°C, preferably to a temperature of about 1,900°C, and the viscosity of the molten glass composition can be controlled to about 1 to 5 cP.

[0022] In the manufacturing system for manufacturing high refractive index glass beads of the present invention, the cutting device comprises a rotatable cutting blade and a cutting blade cooling tank for cooling the cutting blade, and the cutting blade is preferably composed of a drum-type cutting blade made of graphite material, and the diameter of the molten glass composition flow cut by the cutting device is about 0.4 to 1.2Ø, and the temperature can be set to about 1,650 to 1,750℃, and preferably to about 1,700℃.

[0023] In the manufacturing system for manufacturing high-refractive-index glass beads of the present invention, the cooling water of the cooling tank may be set to about 10 to 30°C, and preferably to about 20°C. In addition, it is preferable that the cutting body introduced into the cooling tank be set to a temperature of about 1,200°C or higher.

[0024] The present invention provides a method for manufacturing high-refractive-index glass beads, wherein the manufacturing method comprises the steps of: melting a glass composition having a high refractive index in a skull melting furnace; stabilizing the molten glass composition in a skull clarification furnace, controlling the temperature, and then discharging it to form a molten glass composition flow; cutting the molten glass composition flow into a cutting body using a cutting device; and cooling the cutting body using a cooling bath.

[0025]

[0026] The glass bead according to the present invention has excellent retroreflectivity due to a high refractive index of about 1.9 or higher, and has a large diameter of about 0.4 to 1.2Ø, so it is not easily worn down by external friction, and is formed as an integral glass bead, so retroreflectivity is not significantly reduced even when worn, thus exhibiting the effect of maintaining retroreflectivity for a long time when used in road marking compositions.

[0027] In addition, the manufacturing system for producing high-refractive-index glass beads according to the present invention and the method for producing glass beads using the same provide a glass composition having a high melting point and high specific gravity as a molten material having a constant temperature and viscosity, and not only can it be uniformly cut and cooled, but also prevent devitrification, thereby enabling the mass production of glass beads with excellent visible light transmittance.

[0028]

[0029] Figure 1 illustrates a manufacturing system for manufacturing high-refractive-index integrated glass beads according to the present invention.

[0030] Figure 2 illustrates a skull clarification furnace in a manufacturing system for producing high-refractive-index glass beads according to the present invention.

[0031] FIG. 3 shows examples of devitrification occurring during the cutting process of a glass composition melt flow ((a), (c)) and an example of improper cutting (b).

[0032] Figure 4 shows a glass bead manufactured using a manufacturing system for manufacturing a high refractive index glass bead according to the present invention.

[0033]

[0034] The terms used in this specification are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used in this specification, "comprises" does not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0035] Unless otherwise defined, all terms used herein (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that a person skilled in the art to which the present invention pertains can easily practice the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0037]

[0038] Figure 1 illustrates an embodiment of a manufacturing system for manufacturing high-refractive-index integrated glass beads according to the present invention.

[0039] A manufacturing system for manufacturing high refractive index integrated glass beads according to the present invention includes a skull melting furnace (SMF, 100), a skull refining furnace (SRF, 200), a cutting device (300), and a cooling tank (400).

[0040] The above skull melting furnace (100) can be used without limitation as long as it serves to completely melt a glass composition having a high refractive index in a short time and lower the viscosity of the molten material, but it is preferable to use a high-frequency skull melting furnace for melting a glass composition having a high melting point.

[0041] Since various conventional high-frequency skull melting furnaces can be used as the above high-frequency skull melting furnace, a specific description thereof is omitted, and as an example, a high-frequency skull crucible as disclosed in Patent No. 10-2577700 may be used.

[0042] The temperature of the skull melting furnace (100) can be maintained at a temperature of approximately 1,900 to 2,500°C, and the high refractive index glass composition melted in the skull melting furnace (100) is discharged from the skull melting furnace (100) and supplied to the skull clarification furnace (200).

[0043] In the skull melting furnace (100), components with different specific gravities are mixed and melted, and the melting temperature is also very high, making it impossible to stir the molten material uniformly. Therefore, depending on the location of the skull melting furnace (100), the composition ratio of the molten material may not be uniform, and the temperature is also very high, making it very difficult to manufacture beads directly from the molten material discharged from the skull melting furnace (100).

[0044] The skull clarification furnace (200) is intended to solve these problems and serves to remove bubbles from the molten material supplied from the skull melting furnace (100) and to stabilize and homogenize the molten material. In particular, it serves to discharge the molten material in a constant diameter while maintaining a constant viscosity and temperature. It can be used without limitation as long as it performs these functions, but for the clarification of a glass composition having a high melting point, a high-frequency skull clarification furnace equipped with a high-frequency induction coil (220) is preferred.

[0045] The skull clarification furnace (200) comprises a skull clarification furnace body (210), a high-frequency induction coil (220) and a nozzle (230) provided outside the skull clarification furnace body (210).

[0046] In particular, the nozzle (230) may be composed of a platinum alloy that does not melt at the melting point of a high refractive index glass composition, and it is particularly preferable that it be composed of an alloy of 80% platinum and 20% rhodium, and the nozzle (230) is provided with an orifice (231) having a diameter of about 0.8 to 2.4Ø, so that the molten glass composition discharged through the orifice (231) can form a molten flow (F) with a diameter of about 0.4 to 1.2Ø.

[0047] More preferably, the opening (231) may have a diameter of about 1.6 to 2.0Ø, and the diameter of the molten flow (F) may be formed to be 0.8 to 1.0Ø.

[0048] It is preferable that the nozzle (230) be positioned higher than the lower bottom of the skull clarification furnace body (210) to prevent the opening (231) from being blocked by cooling of the lower bottom.

[0049] The skull clarification furnace (200) can maintain a temperature of about 1,800 to 2,000°C, preferably about 1,900°C, and the high refractive index glass composition melted in the skull clarification furnace (200) maintains a viscosity of about 1 to 5 cP and is discharged through the opening (231) of the nozzle (230) to form a molten flow (F).

[0050] If the viscosity of the molten glass composition is below the above range, it is difficult to form a large diameter molten flow (F), and if it exceeds the above range, it is difficult to discharge through the opening (231).

[0051] The molten flow (F) formed through the skull clarification furnace (200) is supplied to the cutting device (300).

[0052] The cutting device (300) includes a rotatable cutting blade (310) and a cutting blade cooling tank (320) for cooling a portion of the cutting blade (310).

[0053] The above cutting blade (310) serves to cut a molten glass composition flow (F) having a constant diameter and strength at regular intervals. Any blade capable of performing this role can be used without limitation, but a drum-type cutting blade capable of continuously cutting the molten flow (F) is preferred. In particular, a graphite-based cutting blade is preferred, which has a low friction coefficient so that the molten material does not solidify even when in contact with a high-temperature molten material, and has excellent wear resistance, heat resistance, and thermal conductivity so that no thermal damage occurs and cooling is easy.

[0054] The above cutting blade cooling tank (320) cools the cutting blade (310), whose temperature rises during the process of cutting the glass composition molten flow (F), so that the cutting blade (310) can maintain a constant temperature, and also supplies a constant amount of moisture to the surface of the cutting blade (310) to prevent the molten material from adhering to the surface of the cutting blade (310).

[0055]

[0056] The cutting blade (310) continuously cuts the glass composition melt flow (F) with a length (l) similar to the diameter (d) of the glass composition melt flow (F), and the cut body (S) cut by the cutting blade (310) flies through the air and is formed into a sphere by the interfacial tension with the air and is fed into the cooling tank (400).

[0057] During the cutting process of the above glass composition melt flow (F), the temperature of the melt flow (F) must be controlled very precisely, and the temperature of the melt flow (F) can be set to about 1,650 to 1,750°C, and preferably to about 1,700°C.

[0058] If the temperature of the molten flow (F) is below the above range, devitrification occurs and excellent visible light transmittance cannot be expected (see Fig. 3(a)), and if the temperature of the molten flow (F) exceeds the above range, cutting is not completely performed, so a tail-shaped cut body is formed (see Fig. 3(b)), or while flying through the air, it fails to form a sphere and forms an elliptical shape, so a spherical glass bead cannot be obtained.

[0059] As described above, the cutting body (S) cut by the cutting blade (310) flies through the air and takes on a spherical shape, then is introduced into the cooling water of the cooling tank (400) and cooled to produce a glass bead (B) with a diameter of about 0.4 to 1.2Ø, preferably about 0.8 to 1.0Ø.

[0060] The temperature of the cutting body (S) before being introduced into the above cooling water can be maintained at a temperature of about 1,200°C or higher, and preferably set to about 1,300°C.

[0061] If the temperature of the above-mentioned cutting body (S) is below the above-mentioned temperature, devitrification occurs and excellent visible light transmittance cannot be expected (see Fig. 3(c)).

[0062] And the temperature of the water filled in the cooling tank (400) can be set to 10 to 30°C, and preferably to 20°C.

[0063] If the water temperature of the cooling tank (400) is below the above temperature, cracks may occur in the bead due to rapid cooling, and if it exceeds the above temperature, devitrification may occur, and the likelihood of such devitrification increases as the size of the bead (B) increases. That is, it is desirable for the cutting body (S) to be cooled as quickly as possible in the cooling tank (400) so that the difference in cooling speed between the inside and outside of the bead (B) is not large.

[0064]

[0065] The following describes in detail a method for manufacturing high-refractive-index integrated glass beads using a manufacturing system for manufacturing high-refractive-index glass beads.

[0066]

[0067] A glass composition comprising 37 wt% TiO2, 32 wt% BaO, 11 wt% SiO2, 6 wt% ZrO2, and 14 wt% La2O3 was prepared and completely melted in a skull melting furnace heated by high-frequency induction.

[0068] The molten glass composition was transferred to a skull clarification furnace and maintained for about 30 minutes until the temperature of the molten glass composition reached about 1,900°C.

[0069] An opening with a diameter of approximately 1.6Ø provided in the skull clarification furnace was opened to form a molten flow of approximately 0.8Ø, and this was cut using a drum-type graphite cutting blade with a diameter of 350Ø. At this time, the cutting blade rotated at approximately 1,800 rpm.

[0070] During cutting using a cutting blade, the temperature of the molten glass composition flow was maintained at approximately 1,700°C, and the cut body cut by the cutting blade was flown through the air and then cooled in a cooling tank filled with cooling water maintained at approximately 20°C to produce an integral glass bead with a diameter of approximately 0.8Ø. (See Fig. 4)

[0071] The above glass bead has a refractive index of 1.95, which is higher than that of a general glass bead. In addition, it has a large diameter of approximately 0.8Ø and is formed as a single unit, so it can be used as a road sign composition, etc., without a separate process such as coating with an additional high refractive index material. Furthermore, it has the advantage of not only having a high refractive index due to vehicle driving but also maintaining the high refractive index even when worn.

[0072]

[0073] The present invention relates to a manufacturing system used to produce glass beads having a high refractive index and a large diameter, and a method for producing high refractive index glass beads using the same. In particular, it relates to a manufacturing system for producing glass beads having a refractive index of about 1.9 or higher and a diameter of about 0.4 to 1.2Ø, and a method for producing said glass beads using said manufacturing system. Since the glass beads produced according to the present invention have a high refractive index and a large diameter, they can be directly used in retroreflective paints for road signs or lane markings, thus having industrial applicability.

Claims

1. A skull melting furnace for melting a glass composition having a high refractive index; A skull clarification furnace for stabilizing the glass composition melted from the above skull melting furnace and controlling the temperature to form a molten glass composition flow having a constant viscosity and a constant diameter; A cutting device for cutting the molten flow of the above glass composition into a cutting body; A cooling tank for cooling the above-mentioned cutting body; comprising In a manufacturing system for manufacturing high-refractive-index glass beads, The skull clarification furnace is set to a temperature of 1,800 to 2,000°C, and the viscosity of the molten glass composition is adjusted to 1 to 5 cP, and A manufacturing system for producing high refractive index glass beads, characterized in that the diameter of the molten glass composition flow cut by the above-mentioned cutting device is 0.4 to 1.2Ø and the temperature is 1,650 to 1,750℃.

2. In Claim 1, A manufacturing system for manufacturing high-refractive-index glass beads characterized by comprising a skull clarification furnace body, a high-frequency induction coil, and a nozzle.

3. In Claim 2, A manufacturing system for producing high-refractive-index glass beads, characterized in that the nozzle includes an opening with a diameter of 0.8 to 2.4Ø and the nozzle is composed of a platinum-rhodium alloy.

4. In Claim 1, A manufacturing system for manufacturing high-refractive-index glass beads, characterized in that the above-described cutting device includes a rotatable cutting blade and a cutting blade cooling tank for cooling the cutting blade.

5. In Claim 4, A manufacturing system for producing high-refractive-index glass beads, characterized in that the above-mentioned cutting blade is a drum-type cutting blade composed of graphite material.

6. In Claim 1, A manufacturing system for producing high-refractive-index glass beads, characterized in that the cooling water in the above-mentioned cooling tank is set to 10~30℃ 7. In Claim 6, A manufacturing system for producing high-refractive-index glass beads, characterized in that the cutting body introduced into the cooling tank is set to a temperature of 1,200°C or higher 8. A method for manufacturing high-refractive-index glass beads using a manufacturing system for manufacturing high-refractive-index glass beads according to any one of claims 1 to 7, A step of melting a glass composition having a high refractive index in a skull melting furnace; A step of stabilizing the molten glass composition in a skull clarification furnace, controlling the temperature, and then discharging it to form a molten glass composition flow having a constant viscosity and a constant diameter; A step of cutting the molten flow of the above glass composition into a cut body using a cutting device; A step of cooling the above-mentioned cutting body using a cooling bath; Method for manufacturing high-refractive-index glass beads

Images