KR20190030800A - Glass composition with middle refractive index for marking road line and glass bead comprising the same - Google Patents

Abstract

The present invention relates to a glass composition with a middle refractive index for a road sign and a glass bead using the same. The glass composition has an excellent refractive index and durability, and comprises: 20-50 wt% of SiO_2; 30-55 wt% of BaO; 10-25 wt% of TiO_2; and more than 0 and equal to or less than 10 wt% of (Na_2O+ZnO), wherein a weight ratio of the (Na_2O+ZnO) and ZnO, which is ZnO/(Na_2O+ZnO), is 0.5 to 1.

Description

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a middle refractive index glass composition for road marking,

The present invention relates to a refractory glass composition for road marking and a glass bead using the same. The refractory glass composition for road marking has a medium refractive index of 1.65 to 1.8 and a durability of 550 Hv or higher.

Generally, lanes are displayed on the road surface, particularly on the road surface, for the purpose of distinguishing between driving directions and lanes. These lanes are drawn by the lane marking paint. As for the components, pigments, resins, glass beads, filling materials and the like are generally used.

Glass grains used as road pavement and signs are similar to ordinary glass (nd = 1.5) in refractive index, and dangerous situation can be caused by poor display of distinction and direction in bad weather or driving at night.

According to the classification of the glass spheres described in the Korean Standard Standard KS L 2521, one spherical spherical glass is classified into No. 1, No. 2 and No. 3 according to the refractive index, and No. 2 has a medium refractive index of 1.64 to 1.8.

Korean Patent Laid-Open Publication No. 10-1997-0027230 discloses a reflective coating agent for roads. However, since the general coating composition is described, it is required to satisfy the refractive index of the requirement of No. 2 described in Korean Standard Standard KS L 2521 And when such a glass composition is used for road paving, there is a problem that the durability is low and it is easily broken.

Korean Patent Publication No. 10-1997-0027230

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a glass composition having a medium refractive index in a range of 1.65 to 1.8 and a durability of 550 Hv or more in hardness.

The present invention also provides a glass bead using the glass composition.

On the other hand, other unspecified purposes of the present invention will be further considered within the scope of the following detailed description and easily deduced from the effects thereof.

In order to achieve the above object, a glass composition according to an embodiment of the present invention comprises 20 to 50% by weight of SiO ₂ , 30 to 55% by weight of BaO, 10 to 25% by weight of TiO ₂ , and (Na ₂ O + ZnO) (Na ₂ O + ZnO) and ZnO / (Na ₂ O + ZnO) in a weight ratio of ZnO is 0.5 to 1.

In the glass composition in accordance with one embodiment of the present invention, the SiO ₂ and SiO ₂ / TiO ₂ in a weight ratio of TiO ₂ it may be from 1 to 5.

In the glass composition in accordance with one embodiment of the present invention, the BaO and the weight ratio of BaO / SiO ₂ of SiO ₂ it may be from 0.6 to 2.75.

In the glass composition in accordance with one embodiment of the present invention, the BaO and the weight ratio of BaO / TiO ₂ of the TiO ₂ it may be 1.4 to 5.5.

In the glass composition according to an embodiment of the present invention, the glass composition may have a refractive index of 1.65 or more and a Vickers hardness of 550 Hv or more.

In the glass composition according to an embodiment of the present invention, the glass composition may include one or both selected from Li ₂ O and K ₂ O in an amount of 0 to 10 wt%.

In the glass composition according to an embodiment of the present invention, the glass composition may include B ₂ O ₃ , P ₂ O ₅ , Al ₂ O ₃ , CaO, MgO, SrO, GeO ₂ , SnO ₂ , Sb ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ , WO ₃ , Y ₂ O ₃ , ZrO ₂ And La ₂ O ₃ in an amount of 0 to 10% by weight.

The present invention also includes glass beads comprising the above-described glass composition.

The glass composition according to the present invention may have a medium refractive index in the range of 1.65 to 1.8 and a durability of 550 Hv or more in hardness.

Further, since the present invention has excellent refractive index and durability, it can be used as a glass composition for road pavement or sign.

On the other hand, even if the effects are not explicitly mentioned here, the effect described in the following specification, which is expected by the technical features of the present invention, and its potential effects are treated as described in the specification of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a three-component phase balance diagram according to a search for forming regions of SiO ₂ -BaO-TiO ₂ glass according to some embodiments of the present invention. FIG.

Hereinafter, the present invention will be described in detail. The following embodiments and drawings are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. In addition, unless otherwise defined in the technical and scientific terms used herein, unless otherwise defined, the meaning of what is commonly understood by one of ordinary skill in the art to which this invention belongs is as follows, A description of known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted.

In describing the present invention, the glass composition may be a glass composition for producing a refractory glass.

In describing the present invention, the term " refraction " may mean that the refractive index is 1.65 to 1.8.

In the context of the present invention, the term " phase separation " means that unintended secondary phases occur in the glass, and one glass phase is split into two phases of different components, It can mean to be inhibited.

In describing the present invention, the glass bead may be used for a road marking paint or signboard, may be apparently colorless, transparent, and may be partially colored depending on the glass component.

The glass composition according to an embodiment of the present invention includes 20 to 50 wt% of SiO ₂ , 30 to 55 wt% of BaO, 10 to 25 wt% of TiO ₂ , and 0 to 10 wt% of (Na ₂ O + ZnO) , (Na ₂ O + ZnO), and ZnO / (Na ₂ O + ZnO), which is a weight ratio of ZnO, is 0.5 to 1.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a three-component phase balance diagram according to a search for forming regions of SiO ₂ -BaO-TiO ₂ glass according to some embodiments of the present invention. FIG. In detail, the phase balance diagram shown in Fig. 1 shows the phase equilibrium degree of SiO ₂ -BaO-TiO ₂ glass containing 10 wt% of (Na ₂ O + ZnO) A, a phase separation region B, and an unused region C, respectively.

Referring to FIG. 1, the SiO ₂ component of the glass composition of the present invention is a major constituent material of the glass which increases heat resistance and thermal shock resistance, . When the content is high, the melting point of the glass is increased, while the increase of the content of SiO ₂ also reduces the refractive index. Therefore, it is preferable that the content of SiO ₂ is in the range of 20 to 50 wt%, or 25 to 45 wt%.

According to some embodiments of the present invention, when the content of SiO ₂ is less than 20 wt% or exceeds 50 wt%, phase separation may occur during the production of glass, and the glass composition may not melt .

The BaO is a main component for forming a glass structure as a mesh modifier and serves to increase chemical durability, refractive index and hardness. However, when BaO is contained too high, crystallization may occur, the devitrification property and chemical resistance may be lowered and the viscosity may be increased, and when BaO is contained too low, the refractive index and coefficient may be lowered. Therefore, it is preferable that the content of BaO be in the range of 30 to 55 wt%, or 35 to 50 wt%.

According to some preferred embodiments of the present invention, when the content of BaO is less than 30% by weight or exceeds 50% by weight, phase separation may occur during the production of glass, and the glass composition may not melt have.

The TiO ₂ is a component that plays a major role in adjusting the refractive index while securing the transparency of the glass. However, when the content of TiO ₂ is increased, phase separation or crystallization easily occurs and melting and glass formation are difficult, and the coloring phenomenon of yellow is increased due to the increase of Ti ^{3 +} ions. . Therefore, it is preferable that the content of TiO ₂ is in the range of 10 to 25% by weight, or 10 to 20% by weight.

According to some embodiments of the present invention, when the content of the TiO ₂ is less than 10% by weight or exceeds 25% by weight, phase separation may occur during the manufacture of the glass, and the glass composition may not melt have.

The above (Na ₂ O + ZnO) acts as a mesh modifier for changing the mesh structure, and plays a role of improving the stability and fluidity of the glass. Therefore, it is preferable that the content of (Na ₂ O + ZnO) is in the range of more than 0 to 10% by weight, or 2 to 10% by weight.

According to some preferred embodiments of the present invention, when the content of (Na ₂ O + ZnO) is more than 10% by weight, stability of the glass may be deteriorated and phase separation may occur, and the content of (Na ₂ O + ZnO) Is contained in an amount of less than 2% by weight, the hardness of the glass may be somewhat reduced as the content of (Na ₂ O + ZnO) decreases, and the glass may be partially colored.

Meanwhile, in the glass composition according to other embodiments of the present invention, the weight ratio of (Na ₂ O + ZnO) and ZnO, ZnO / (Na ₂ O + ZnO) may be 0.5 to 1. In detail, when ZnO / (Na ₂ O + ZnO) is less than 0.5, phase separation may occur. Therefore, it is preferable that ZnO / (Na ₂ O + ZnO) be in the range of 0.5 or more to less than 1 or 0.5 to 0.95.

Further, in the glass composition in accordance with some embodiments of the present invention, the SiO ₂ and SiO ₂ / TiO ₂ in a weight ratio of TiO ₂ it may be from 1 to 5. In detail, when the SiO ₂ / TiO ₂ is less than 1, the hardness of the produced glass may be decreased or the refractive index of the produced glass may be decreased when the SiO ₂ / TiO ₂ is more than 5 .

Further, in the glass composition in accordance with some embodiments of the invention, the weight ratio of BaO and BaO / SiO ₂ of SiO ₂ may be from 0.6 to 2.75. In detail, when the BaO / SiO ₂ is less than 0.6, the refractive index of the glass can be decreased, and when the BaO / SiO ₂ is more than 2.75, the hardness of the glass can be lowered.

Further, in the glass composition in accordance with some embodiments of the invention, the weight ratio of BaO and the BaO / TiO ₂ of the TiO ₂ may be 1.4 to 5.5. In detail, when the BaO / TiO ₂ is less than 1.4, the refractive index of the prepared glass may be decreased. When the BaO / TiO ₂ is more than 5.5, the glass may be phase-separated or the hardness of the glass produced may be lowered.

Meanwhile, the glass composition according to an embodiment of the present invention may include one or both selected from Li ₂ O and K ₂ O in an amount of 0 to 10 wt%. Li ₂ O and K ₂ O may serve to cut the glass of SiO ₂ in the glass and lower the glass transition temperature (Tg) and softening point (Ts) to increase the fluidity of the glass. When Li ₂ O, K ₂ O or Li ₂ O and K ₂ O are included independently in the glass composition in an amount of more than 10% by weight, glass stability may be deteriorated and coloring may occur more easily after firing.

In addition, the glass composition according to an embodiment of the present invention may include at least one of B ₂ O ₃ , P ₂ O ₅ , Al ₂ O ₃ , CaO, MgO, SrO, GeO ₂ , SnO ₂ , Sb ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ , WO ₃ , Y ₂ O ₃ , ZrO ₂ And La ₂ O ₃ in an amount of 0 to 10% by weight. Accordingly, the glass composition according to the present invention can improve the stability of the glass. Wherein the glass composition is selected from the group consisting of B ₂ O ₃ , P ₂ O ₅ , Al ₂ O ₃ , CaO, MgO, SrO, GeO ₂ , SnO ₂ , Sb ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ , WO ₃ , Y ₂ O ₃ , ZrO ₂ and La ₂ O ₃ is contained in an amount of more than 10% by weight, crystallization of the glass may occur and the fluidity may be lowered.

The present invention also includes glass beads comprising the above-described glass composition.

The glass bead according to an embodiment of the present invention can be manufactured through post-processing of glass produced from the above-described glass composition. In this case, the post-processing may be any conventional processing method in this field, and examples thereof include, for example, grinding and polishing.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the present invention is not limited to the following examples.

Examples 1 to 18, Comparative Examples 1 to 3

The glass compositions according to the present invention are weighed by composition according to each example as shown in Table 1 below. Then, the mixture of the composition shown in Table 1 was melted at 1400 ° C for 1 hour, quenched on a copper plate at room temperature, transferred to a heat treatment furnace, and then cooled at 550 ° C for 2 hours to prepare glass.

The prepared glass was classified into transparent glass and phase separated glass. Transparent glass was processed into glass specimens of constant size to measure refractive index and Vickers hardness. The standard for machining was set to 8 mm (W) x 20 mm (D) x 4 to 6 mm (H), and the surface was polished by a diamond cutter to minimize surface roughness.

The following properties of the glass specimens thus prepared were measured, and the results are shown in Table 1.

 (1) phase separation

When phase separation occurs, a band is generated in the glass and on the surface depending on the presence of other phases of the refractive index, thereby lowering the transparency. The phase separation was visually confirmed, the phase separated glass specimen was denoted by O and the phase specimen which was not phase separated was denoted by X.

(2) Refractive index

The refractive index was measured with a conventional Abbe refractometer. Specifically, the refractive index was measured by applying a refraction liquid between the prism and the glass sample using a light source at a wavelength band of 589 nm.

(3) Vickers hardness

The Vickers hardness was measured with a Vickers hardness tester manufactured by Akashi AVK-CO. Specifically, according to the ASTM E 92 Vickers hardness test method, the sample was held at a load of 0.1 kgf (0.98 N) for 10 seconds and measured using the following equation.

Hv = 0.001854 x (F / d ² )

Where Hv is the Vickers hardness (GPa), F is the test load (N), and d is the arithmetic mean (mm) of the two diagonal lines of the Vickers indentation.

Unit: wt% SiO ₂ BaO TiO ₂ Na ₂ O
+ ZnO Refractive index
(Wavelength: 589 nm) Vickers
Hardness (Hv) BaO / SiO ₂ BaO / TiO ₂ SiO ₂ / TiO ₂ Prize
detach Example 1 20 50 20 10 1.7635 630.5 2.50 2.50 1.00 X Example 2 20 55 15 10 1.7409 553.9 2.75 3.67 1.33 X Example 3 25 55 10 10 1.7112 552.0 2.20 5.50 2.50 X Example 4 25 50 15 10 1.7315 590.93 2.00 3.33 1.67 X Example 5 25 45 20 10 1.7568 616.3 1.80 2.25 1.25 X Example 6 30 50 10 10 1.7016 575.6 1.67 5.00 3.00 X Example 7 30 45 15 10 1.7256 610.7 1.50 3.00 2.00 X Example 8 30 40 20 10 1.7511 654.83 1.33 2.00 1.50 X Example 9 30 35 25 10 1.7850 668.9 1.17 1.40 1.20 X Example 10 40 40 10 10 1.6794 616.78 1.00 4.00 4.00 X Example 11 40 35 15 10 1.7038 615.42 0.88 2.33 2.67 X Example 12 40 30 20 10 1.7419 636.0 0.75 1.50 2.00 X Example 13 50 30 10 10 1.6575 614.7 0.60 3.00 5.00 X Example 14 35 45 10 10 1.6936 596.82 1.29 4.50 3.50 X Example 15 35 40 15 10 1.7289 632.12 1.14 2.67 2.33 X Example 16 35 35 20 10 1.7548 638.06 1.00 1.75 1.75 X Example 17 45 35 10 10 1.6644 618.9 0.78 3.50 4.50 X Example 18 45 30 15 10 1.6922 625.3 0.67 2.00 3.00 X Comparative Example 1 20 45 25 10 1.8210 508.3 2.25 1.80 0.80 X Comparative Example 2 56 24 10 10 1.60 617.5 0.60 2.40 5.60 X Comparative Example 3 20 60 10 10 1.7261 523.1 3.00 6.00 2.00 X Comparative Example 4 55 25 10 10 1.61 616.3 0.45 2.50 5.50 X

In Table 1, the weight ratio of Na ₂ O and ZnO, Na ₂ O: ZnO, is 1: 1.

As can be seen in Table 1 above, the glass compositions of Examples 1 to 18 according to the present invention comprise 20 to 50 wt% of SiO ₂ , 30 to 55 wt% of BaO, 10 to 25 wt% of TiO ₂ , and (N ₂ O + ZnO) in the range of more than 0 to 10 wt%, the phase separation of the produced glass was prevented, the refractive index was about 1.65 to 1.8, and the Vickers hardness value was about 550 to 700 Hv.

However, as can be seen from Comparative Examples 1 and 2, when the SiO ₂ / TiO _{2 content} is less than 1, the Vickers hardness value is lowered to less than 550 Hv. When SiO ₂ / TiO ₂ is more than 5, the refractive index is lowered to less than 1.65.

Further, as can be seen from Comparative Example 3, when the BaO / SiO ₂ exceeds 2.75 and the BaO / TiO ₂ exceeds 5.5, the Vickers hardness value is lowered to less than 550 Hv.

In addition, as can be seen from Comparative Example 4, when the BaO / SiO ₂ is less than 0.6 and the SiO ₂ / TiO ₂ is more than 5, the refractive index is lowered to less than 1.65.

Examples 19 to 20, Comparative Examples 5 to 6

A final glass sample was prepared in the same manner as in Example 9 except that the weight ratio of ZnO to (N ₂ O + ZnO) ZnO / (Na ₂ O + ZnO) was 0, 0.25, 0.50, 0.75 and 1.00 . The phase separation, refractive index and Vickers hardness of the glass specimen according to Example 9, Examples 19 to 20 and Comparative Examples 4 to 5 are shown in Table 2.

Unit: wt% SiO ₂ BaO TiO ₂ Na ₂ O + ZnO Refractive index
(Wavelength: 589 nm) Vickers
Hardness (Hv) ZnO / (Na ₂ O + ZnO) Phase separation Comparative Example 5 30 35 25 10 - - 0 O Comparative Example 6 30 35 25 10 - - 0.25 O Example 9 30 35 25 10 1.7850 668.9 0.50 X Example 19 30 35 25 10 1.7696 644.3 0.75 X Example 20 30 35 25 10 1.7899 628.1 1.00 X

As can be seen from Table 2, the glass compositions of Example 9 and Examples 19 to 20 according to the present invention exhibited no phase separation due to the ZnO / (Na ₂ O + ZnO) being 0.5 to 1, About 1.76 to 1.79, and a Vickers hardness of about 620 to 670 Hv.

However, the glass compositions according to Comparative Examples 5 and 6 exhibited phase separation when the ZnO / (Na ₂ O + ZnO) was less than 0.5.

Examples 21 to 23 and Comparative Example 7

The final glass specimen was prepared in the same manner as in Example 9 except that the content of (Na ₂ O + ZnO) described in Example 9 was changed to about 2 to 12 wt%. The detailed compositions are listed in Table 3 below. The phase separation, refractive index and Vickers hardness of the glass specimen according to Example 9, Examples 21 to 23, and Comparative Example 7 are shown in Table 3.

Unit: wt% SiO ₂ BaO TiO ₂ Na ₂ O + ZnO Refractive index
(Wavelength: 589 nm) Vickers
Hardness (Hv) Phase separation Example 21 32.433 37.838 27.027 2.702 1.7864 643.0 X Example 22 31.579 36.842 26.315 5.264 1.7833 661.4 X Example 23 30.769 35.898 25.641 7.692 1.7741 678.5 X Example 9 30 35 25 10 1.7850 668.9 X Comparative Example 7 29.268 34.146 24.390 12.196 - - O

As can be seen from Table 3, the glass compositions of Example 9 and Examples 21 to 23 according to the present invention had a content of (Na ₂ O + ZnO) of about 2.5 to 10% by weight, , A refractive index of about 1.77 to 1.78, and a Vickers hardness of about 640 to 670 Hv.

However, the glass composition according to Comparative Example 7 exhibited phase separation when the (Na ₂ O + ZnO) was about 12 wt%.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (8)

SiO ₂ and contains less than 20 to 50 wt%, BaO 30 to 55 wt%, TiO ₂ 10 to 25% by weight and (Na ₂ O + ZnO) 0 is more than 10% by weight,
(Na ₂ O + ZnO) and the weight ratio of ZnO to ZnO / (Na ₂ O + ZnO) is 0.5 to 1.
The method according to claim 1,
The SiO ₂ and SiO ₂ / TiO ₂ weight ratio of TiO ₂ in the glass composition, characterized in that 1 to 5.
The method according to claim 1,
Of BaO / SiO ₂ weight ratio of said BaO, and SiO ₂ is a glass composition characterized in that 0.6 to 2.75.
The method according to claim 1,
Wherein the weight ratio of BaO and TiO ₂ , BaO / TiO _2, is 1.4 to 5.5.
The method according to claim 1,
Wherein the glass composition has a refractive index of 1.65 or more and a Vickers hardness of 550 Hv or more.
The method according to claim 1,
Wherein the glass composition comprises from 0 to 10% by weight of one or both selected from Li ₂ O and K ₂ O.
The method according to claim 1,
The composition of glass _{B 2 O 3, P 2 O} 5, Al 2 O 3, CaO, MgO, SrO, GeO 2, SnO 2, Sb 2 O 3, Ga 2 O 3, In 2 O 3, WO 3, Y ₂ O ₃ , ZrO ₂ And La ₂ O ₃ in an amount of 0 to 10% by weight.
A glass bead comprising a glass composition according to any one of claims 1 to 7.

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