KR100462949B1 - Glass composition and bead with high refractivity - Google Patents

Abstract

The present invention relates to a high refractive index glass composition and a glass egg using the same, the composition is a high refractive index oxide of TiO ₂ and BaO as a main component, a stabilizer oxide SiO ₂ as a stabilizer, MgO, CaO, ZnO, Na ₂ as a stabilizer One or two or more mixtures selected from the group consisting of O and K ₂ O, containing ZrO ₂ , Al ₂ O ₃ or mixtures thereof as devitrification inhibitors, and having a high refractive index glass grain of nd = 1.9 or more easily and stably Make it possible to manufacture.

Description

Glass composition and bead with high refractivity

The present invention relates to a glass composition having a high refractive index and a glass egg using the same, and more particularly, to a glass composition having a refractive index of nd = 1.9 or more and a glass egg using the same.

The application fields of glass eggs can be said to be diverse, and the application fields of glass beads currently in use can be divided into reflective glass balls using optical properties, which are the biggest advantages of glass, and products using spherical shape characteristics. have.

Among them, the application field for the road marking on the road surface has been used glass beads with refractive index similar to that of ordinary glass (nd = 1.5), but the traffic volume is not good and the structure of the road is poor. High-refractive glass grains are used in part to display a safe and clear car when driving at night, and the application field is gradually expanding.

In addition, the high refractive glass glass applied to the reflective sheet of the road sign is required glass glass of higher refractive index than the glass glass currently used, the demand is gradually increasing to provide a safe and comfortable traffic culture.

In general, the glass grains used for road pavement and signage have a refractive index that is similar to that of ordinary glass, and may cause dangerous situations due to poorly distinguishing and indicating the direction of the car as its original purpose in bad weather or at night. Can be. Therefore, in recent years, the demand for high refractive glass grains that can be clearly displayed at a long distance is increasing, and in the future, high refractive glass grains can be expected to occupy the current low refractive glass grains.

Glass grains, which use optical properties, the biggest characteristic of glass, can be divided into road floors and road signs. Flooring can be divided into glass grains for road signs, which are used as reflective materials after being mixed with paints, and markers used for signs. They are divided according to refractive index and size. In other words, the glass grains mixed in the paint have a refractive index of about 1.5, which is a measure of reflection, and a size of about 100 microns to 2000 microns. However, the glass beads used for the signs are glass beads having a high refractive index of 1.9 or more, and small glass beads having a size of 20 microns to 100 microns are used. In order to produce such high refractive glass grains, conventional glass compositions cannot be produced, and glass compositions are very difficult and vitrification is difficult.

With the existing composition and manufacturing method (Korean Patent Publication No. 96-1656), vitrification is too difficult and it is difficult to manufacture high refractive glass of 1.9 or more. In addition, the patent publications (JP33-3352, JP55-47245, JP54-139916, JP60-54253, JP54-25925) can be said to be a glass composition showing a high refractive index, but there are many difficulties in vitrification.

The content of TiO ₂ and BaO is an important component of high refractive index in the production of high refractive glass eggs. However, the glass containing a large amount of TiO ₂ is very difficult to vitrification process to make a clear glass, therefore, it is required to select a suitable vitrification composition for the production of glass beads, without devitrification in the glass manufacturing process It is the core technology to make a glass of a certain size.

In general, high refractive index glass can improve the stability of TiO ₂ and glass for easy vitrification. However, the glass grains having a refractive index of 1.7 or less can be used because the content of SiO ₂ is decreased or the content of SiO ₂ is higher. Manufactured and used. Therefore, the application field is limited, and has not been able to meet the various needs of the customer. In particular, in the conventional glass preparation, high temperature melting was required because of the high content of SiO ₂ .

In addition, the glass composition having a high refractive index of 1.9 or more in the prior art contains PbO, an environmental pollutant to increase the refractive index, and contains a large amount of TiO ₂ to increase the refractive index. In this case, TiO ₂ prevents vitrification and Makes manufacturing difficult.

Accordingly, an object of the present invention is to provide a stable glass composition exhibiting a high refractive index of 1.9 or more and easy to manufacture with glass in view of the above problems of the prior art as described above and a glass egg using the same.

In order to solve the above problems, the present inventors have adjusted the amount of SiO ₂ , ZrO ₂ , and Al ₂ O ₃ which can enhance the stability of the glass based on the main components TiO ₂ and BaO as glass compositions. Modified oxides, which can weaken the glass, were also added in compositions that could stabilize the glass, resulting in the development of the desired glass composition.

1 is a view schematically showing a molding machine for producing glass balls,

2 is an electron micrograph of a spherical glass ball formed,

3 is a graph showing the viscosity of common glass and conventional high refractive glass,

4 is a graph showing the effect of modified oxide on the melting point of the glass in the present composition.

Therefore, in the high refractive glass composition according to the present invention,

(a) 35 to 75 wt% of high refractive index oxide TiO ₂ and 25 to 65 wt% BaO,

(b) 3 to 20 parts by weight of SiO ₂ per 100 parts by weight of the main component as a stabilizing oxide,

(c) 1 to 20 parts by weight of one or two or more mixtures selected from the group consisting of MgO, CaO, ZnO, Na ₂ O and K ₂ O per 100 parts by weight of the main component as a modified oxide,

(d) 1 to 15 parts by weight of ZrO ₂ , Al ₂ O _3, or a mixture thereof, per 100 parts by weight of the main component as an devitrification inhibitor, wherein ZrO ₂ , Al ₂ O ₃ , MgO, CaO, ZnO, Na ₂ O And the maximum content of each of K ₂ O is 8% or less ZrO _2, 8% or less Al ₂ O ₃ , 7% or less MgO, 7% or less CaO, 7% or less, ZnO 7% or less, Na ₂ O + K ₂ O based on the total composition weight. A high refractive glass composition is provided which is 5% or less.

Hereinafter, the present invention will be described in more detail.

TiO ₂ contained as a main component in the present composition is nd 2.9, and BaO is a high refractive index oxide of nd 1.98. The content ratio of TiO ₂ to BaO in the present composition is preferably 35:65 to 75:25 by weight. BaO in the said main component also has the effect of suppressing devitrification.

Figure 3 shows the viscosity characteristics of a high refractive glass composition consisting of typical soda lime silicate (sodalimesilicate) glass (corning glass 710a), TiO ₂ and BaO only. As can be seen in FIG. 3, the viscosity of Corning glass 710a, which is a representative composition of glass, is known to exhibit a gentle viscosity curve with respect to temperature, while the composition of high refractive glass has a low viscosity up to 1300 ° C. ), The viscosity suddenly increases to more than 10 ⁵ poise at a temperature near 1300 ℃, showing a sudden viscosity curve, the viscosity can not be measured beyond the viscosity measurement limit. As such, the glass having a sharp viscosity curve has difficulty in producing glass as compared to a glass composition having a gentle curve. Especially in the case of molding, glass is usually formed in the viscosity range of 10 ³ to 10 ⁵ poise. The high refractive glass composition shows the characteristic that the viscosity suddenly increases in the temperature range of this viscosity. Almost no. In addition, such glass has difficulty in melting as well as molding. Looking at the melting process, it can be said that the melting process starts with melting as the temperature increases and decomposition and shrinkage of the raw materials and solid phase reactions occur. That is, such high refractive glass has such characteristics that the process occurs in an instant at a temperature near 1300 ℃, and the viscosity at the same time with melting is very low (about 100 cP or less), the refractory erosion is very severe.

As described above, the glass composition cannot stabilize the glass only by the high refractive index oxides TiO ₂ and BaO. Thus, in the present invention, a stabilized oxide, a modified oxide, and an devitrification inhibitor are used as additives for stabilizing the glass while maintaining a high refractive index. It is the biggest feature that it improves stability by containing in.

In the present composition, one or two or more mixtures selected from the group consisting of SiO ₂ as a stabilizing oxide, MgO, CaO, ZnO, Na ₂ O, and K ₂ O as a modified oxide, and ZrO ₂ , Al as an anti-rusting oxide ₂ O ₃ or mixtures thereof are used.

SiO _{2, which} is a stabilizing oxide, may make the glass stable, but if it is added too much, the refractive index of the glass may be lowered. Therefore, it is preferable to contain SiO _{2 in an} amount of 3 to 20 parts by weight based on 100 parts by weight of the main component.

In addition, since the modified oxide of glass can also reduce the refractive index of glass when it uses excessively, the content of the said modified oxide in this composition is 1-20 weight part per 100 weight part of said main components.

In addition, since the devitrification-suppressing oxide can also reduce the refractive index of glass when used in excess, the content of the devitrification-suppressing oxide in this composition is 1-15 weight part per 100 weight part of said main components.

Preferably, each of ZrO ₂ , Al ₂ O ₃ , MgO, CaO, ZnO, Na ₂ O and K ₂ O in the present composition is based on the total weight of the composition, up to 8% ZrO _{2, up to} 8% Al ₂ O ₃ , MgO 7% or less, it is desirable to contain more than 7% CaO or less, 7% or less _{ZnO, Na 2 O + K 2 O} 5%.

The glass composition of the present invention may be prepared by melting the glass composition, and then crushing, pulverizing and spheronizing the glass composition. Melting of the glass composition may be carried out in an electric furnace or the like, and the crushing of the glass produced by melting is to prevent devitrification of the glass. For example, the glass melt may be poured into water to prepare a cullet. The manufactured cullet may be preferably pulverized in a ball mill or the like so as to have a particle size range of 20 to 90 µm, spherical in a molding machine as illustrated in FIG.

The glass grains thus prepared are stable and exhibit a high refractive index of nd 1.9 or more.

Hereinafter, the present invention will be described in more detail with reference to an embodiment consisting of a vitrification step and a prototype completion step thereafter. However, the present invention is not limited to the following examples.

EXAMPLE

※ Experiment I-1 to I-6

To prepare a glass composition shown in Table 1 below. The composition of Table 1 is satisfied with TiO ₂ (nd 2.9) and BaO (nd 1.98) as high refractive index oxide, based on TiO ₂ -BaO-SiO ₂ -based glass. Looking at each oxide of the selected glass composition, the refractive index was composed of a composition of 1.9 or more and a group of 2.0 or more, and in order to suppress the devitrification was made into three groups by adding alkaline earth oxide, ZrO ₂ , Al ₂ O ₃ And, The composition was selected by appropriately containing the RO component which is an intermediate oxide. All of the above batches were prepared in a 100 g batch using first-class reagents as raw materials. The batch composition calculated by the mixing method (batch) was measured to prepare one batch as a 100g unit, and acetone and the batch was mixed in a ratio of about 1: 1 to carry out mixing in induction. After the mixing was performed for about 10 minutes, the prepared batch was dried for about 1 hour in a dryer. Melting of the dried batch using a alumina (Al ₂ O ₃ ) crucible was melted for more than 1 hour in an electric furnace of 1350 ℃ or more to prepare a glass. The molten glass was prepared by pouring a glass melt in water to prevent devitrification of the glass. The prepared cullet was crushed in a ball mill to have a particle size range of 20 to 90 µm and spherical in the molding machine of FIG.

As a result, spherical glass grains as in Fig. 2 having a particle size of 20 to 90 µm, a refractive index (Bequeline method) of 1.9 to 2.0 and a density of 4.2 to 4.6 were obtained.

Experiment No. Ingredients (% by weight) Refractive index Glass TiO ₂ BaO SiO ₂ ZrO ₂ Al ₂ O ₃ MgO CaO ZnO Ⅰ-1 40 43 7 5 5 1.91 Good Ⅰ-2 40 43 7 5 5 1.91 Good Ⅰ-3 40 43 7 5 5 1.91 Good Ⅰ-4 50 33 7 5 5 2.01 Throwing Ⅰ-5 50 33 7 5 5 2.03 Good Ⅰ-6 50 33 7 5 5 2.03 Good

※ Experiment Ⅰ-7 to Ⅰ-12

The same procedure as in the above experiment was repeated except that the glass composition was prepared with the composition shown in Table 2 below.

Experiment No. Ingredients (% by weight) Refractive index Glass TiO ₂ BaO SiO ₂ ZrO ₂ MgO CaO ZnO Na ₂ O K ₂ O Ⅰ-7 56 30.5 5 3 2 2 One 0.5 2.1 or higher good Ⅰ-8 56 30.5 7 2 2 2 0.5 2.1 or higher good Ⅰ-9 57 30 7 2 1.4 2 0.3 0.3 2.1 or higher good Ⅰ-10 57 30 5 2 3.4 2 0.3 0.3 2.1 or higher good Ⅰ-11 59 28.4 7 2 3 0.3 0.3 2.1 or higher Throwing Ⅰ-12 59 29.4 7 2 2 0.3 0.3 2.1 or higher good

It can be seen at the differential thermal analysis (DTA) crystallization temperature that the compositions according to the present invention achieve high refractive index and have excellent glass stability.

In Table 3 showing the DTA results for Experimental Compositions I-1 to I-6, comparing Experimental Compositions I-1-3 and I-4-6, which can be a stabilization measure for glass (T _x1 -T The temperature difference of _g ) shows significantly higher temperature difference in the glass of I-2 and I-5 with CaO as modified oxide compared to the glass of I-1,3 and II-4,6 with MgO and ZnO. This shows that CaO in the glass composition of the present invention greatly contributes to stabilizing the glass compared to other components.

Thermal Properties Glass Composition Transition point Tg (℃) Crystallization Temperature Tx (℃) Tg-Tx Ⅰ-1 713 768 55 Ⅰ-2 720 860 140 Ⅰ-3 708 775 67 Ⅰ-4 724 774 50 Ⅰ-5 727 821 94 Ⅰ-6 714 761 47

Table 3 Tg (transition point) and Tx (crystallization temperature) to determine the stabilization of the glass

In addition, Figure 4 shows the viscosity curve of the experiments I-1 to I-3 glass compositions. The composition of I-1 using MgO as a modified oxide increased rapidly at a temperature near about 1285 ° C., and the composition of I-3 using ZnO at a temperature near about 1225 ° C. and I-2 using CaO. In the case of the composition, it can be seen that there is a sudden increase in viscosity at a temperature near about 1185 ℃. Therefore, it was found that the effect of lowering the stability of the glass and the melting point of the glass by 100 ° C. or more in the selection of the modified oxide was obtained.

As described above, the composition of the present invention is environmentally friendly, and has an effect of easily and stably producing a high refractive index glass grain of nd 1.9 or more.

Claims (6)

In the high refractive glass composition, (a) 35 to 75 wt% of high refractive index oxide TiO ₂ and 25 to 65 wt% of BaO as main components, (b) 3 to 20 parts by weight of SiO ₂ per 100 parts by weight of the main component as a stabilizing oxide, (c) 1 to 20 parts by weight of one or two or more mixtures selected from the group consisting of MgO, CaO, ZnO, Na ₂ O and K ₂ O per 100 parts by weight of the main component as a modified oxide, (d) 1 to 15 parts by weight of ZrO ₂ , Al ₂ O _3, or a mixture thereof, per 100 parts by weight of the main component as an devitrification inhibitor, wherein ZrO ₂ , Al ₂ O ₃ , MgO, CaO, ZnO, Na ₂ O And the maximum content of each of K ₂ O is 8% or less ZrO _2, 8% or less Al ₂ O ₃ , 7% or less MgO, 7% or less CaO, 7% or less, ZnO 7% or less, Na ₂ O + K ₂ O based on the total composition weight. High refractive index glass composition, characterized in that 5% or less. delete delete delete delete delete