JPH0144657B2 - - Google Patents
Info
- Publication number
- JPH0144657B2 JPH0144657B2 JP58039626A JP3962683A JPH0144657B2 JP H0144657 B2 JPH0144657 B2 JP H0144657B2 JP 58039626 A JP58039626 A JP 58039626A JP 3962683 A JP3962683 A JP 3962683A JP H0144657 B2 JPH0144657 B2 JP H0144657B2
- Authority
- JP
- Japan
- Prior art keywords
- glass
- glass beads
- refractive index
- tio
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/062—Glass compositions containing silica with less than 40% silica by weight
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Glass Compositions (AREA)
Description
〔発明の技術分野〕
本発明は、再帰反射用の高屈折率ガラスビーズ
に関するもので、特に屈折率を増加させるために
加熱処理をしたガラスビーズのソーラリゼーシヨ
ンを防止させた高屈折率ガラスビーズに関する。
〔発明の技術的背景〕
再帰反射シート等に使用されるガラスビーズ
は、高輝度が要求されるため屈折率の高いガラス
が必要である。一般に屈折率の高いガラスは、
PbO、TiO2.BaO、La2O5のような高屈折の酸化
物が多量に使われる。しかしPbO系のガラスは公
害上の問題とガラス素地が黄色く着色する問題が
あり、またLa2O5は高価であることから、最近で
はTiO2−BaO系のガラスで、TiO2とBaOとを合
計で60重量％以上含むガラスの採用が多くなつて
いる。ところがTiO2とBaOとを60重量％含むガ
ラスであつても、通常の屈折率は2.00〜2.20程度
である。再帰反射シート等に使用されるガラスビ
ーズの屈折率は、2.23〜2.30程度であることが望
ましいために、加熱処理を行ない屈折率を増加す
る方法が採られている。
〔背景技術の問題点〕
加熱処理を行なわないガラスビーズはソーラリ
ゼーシヨンを起さないが、加熱処理を行なうとガ
ラス中のTiに絡む電子遷移で、太陽光の紫外線
によつてソーラリゼーシヨンを起し、ガラスビー
ズは黒く変色する。そのため白色系の再帰反射シ
ートなどに使用した場合に問題となる。
従来これらの対策手段としては、反射シート
の樹脂に紫外線吸収剤を入れて紫外線を出来る限
りカツトする方法、TiO2−BaO系ガラスの
TiO2を他の高屈折率酸化物（例えばZrO2、ZnO）
で置換する方法などが採られていたが、は完全
な紫外線のカツトが出来ず灰色化する。はガラ
ス化範囲が狭小及びガラスの溶融性困難な問題が
発生し不都合があつた。
一方テレビジヨンバルブ用ガラス組成において
Ｘ線吸収による変色防止のためにCeO2を添加す
ることが知られているが、特にTiO2−BaO系ガ
ラスではCeO2を添加することにより、Fe2O3と
TiO2及びTiO2とCeO2の結合でガラス素地が着色
し易くなる。
〔発明の目的〕
本発明は、TiO2−BaO系透明ガラスビーズの
屈折率を増加するために加熱処理を行つたガラス
ビーズにおいて、太陽光等の紫外線照射によつて
生ずるソーラリゼーシヨンを防止することを目的
とする。
〔発明の概要〕
本発明は、加熱処理を行つたガラスビーズのソ
ーラリゼーシヨン防止を、ガラス中に含まれる
Fe2O3含有量の制限とCeO2を添加することによ
つて達成したものである。すなわち、TiO2およ
びBaOのいずれか１種または２種を少なくとも
60重量％含み、屈折率を増加させるために加熱処
理をしたガラスビーズにおいて、ソーラリゼーシ
ヨンについてFe2O3が存在すると顕著であること
を見い出し、これを0.01重量％以下にすれば可成
り変色防止が出来るが、更にCeO2を0.01〜0.5重
量％加えることによつてその効果は完壁となる。
ここでCeO2は、0.5重量％を超えるとTiO2との
関係でガラス素地が着色するため、それ以下にす
ることが重要である。
〔発明の実施例〕
以下本発明の実施例について詳細に説明する。
ガラスビーズ用高屈折率ガラスの基本組成とし
て次の２種類を選定した。
[Technical Field of the Invention] The present invention relates to high refractive index glass beads for retroreflection, and in particular, high refractive index glass that prevents solarization of glass beads that have been heat-treated to increase the refractive index. Regarding beads. [Technical Background of the Invention] Glass beads used in retroreflective sheets and the like are required to have high brightness, so glass with a high refractive index is required. Generally, glass with a high refractive index is
Highly refractive oxides such as PbO, TiO 2 .BaO, and La 2 O 5 are used in large quantities. However, PbO-based glasses have problems with pollution and yellowing of the glass base, and La 2 O 5 is expensive, so recently TiO 2 -BaO-based glasses have been developed that combine TiO 2 and BaO. Glass containing a total of 60% or more by weight is increasingly being used. However, even if the glass contains 60% by weight of TiO 2 and BaO, the normal refractive index is about 2.00 to 2.20. Since it is desirable that the refractive index of glass beads used in retroreflective sheets and the like is about 2.23 to 2.30, a method of increasing the refractive index by performing heat treatment is adopted. [Problems in the background technology] Glass beads that are not heat-treated do not undergo solarization, but when heat-treated, solarization occurs due to electron transitions associated with Ti in the glass. The glass beads turn black. This poses a problem when used in white retroreflective sheets. Conventional countermeasures for these problems include adding ultraviolet absorbers to the resin of reflective sheets to block as much ultraviolet rays as possible, and using TiO 2 -BaO glass.
TiO 2 with other high refractive index oxides (e.g. ZrO 2 , ZnO)
Although methods such as replacing the UV rays with UV rays have been adopted, they cannot completely block UV rays and turn gray. However, there were disadvantages in that the vitrification range was narrow and the meltability of the glass was difficult. On the other hand, it is known that CeO 2 is added to glass compositions for television bulbs in order to prevent discoloration due to X-ray absorption, but especially in TiO 2 -BaO glass, by adding CeO 2 , Fe 2 O 3 and
The glass substrate becomes easily colored due to TiO 2 and the combination of TiO 2 and CeO 2 . [Object of the Invention] The present invention is directed to preventing solarization caused by ultraviolet irradiation from sunlight etc. in glass beads heat-treated to increase the refractive index of TiO 2 -BaO-based transparent glass beads. The purpose is to [Summary of the Invention] The present invention prevents solarization of heat-treated glass beads.
This was achieved by limiting the Fe 2 O 3 content and adding CeO 2 . That is, at least one or both of TiO 2 and BaO
We found that in glass beads containing 60% by weight and heat-treated to increase the refractive index, solarization is significant when Fe 2 O 3 is present, and it can be achieved by reducing this to 0.01% by weight or less. Although discoloration can be prevented, the effect becomes complete by adding 0.01 to 0.5% by weight of CeO 2 . Here, if CeO 2 exceeds 0.5% by weight, the glass substrate will be colored due to its relationship with TiO 2 , so it is important to keep it below that amount. [Embodiments of the Invention] Examples of the present invention will be described in detail below. The following two types of basic compositions of high refractive index glass for glass beads were selected.
【表】
ガラス原料は、特に鉄分等不純物の少ないもの
を選んで使用し、この原料を前記表−１の基本組
成に合わせるとともに、Fe2O3を0.003、0.01、
0.03重量％に調製し、且つCeO2が０、0.2、0.3重
量％となるように調合した。この調合物を白金ル
ツボに収容して1350〜1450℃、約30分間電気炉で
溶融し、粉砕工程を経てガラスビーズに成形し
た。その後700〜710℃の電気炉で約15時間加熱処
理を行ない、屈折率をNo.１及びNo.２ガラスとも
2.25とした。
更にこのガラスビーズを使用して再帰反射シー
トを作成し評価試験用とした。
またソーラリゼーシヨンの表示は△Ｅ値（色差
値）で行ない、その測定は色差計を使用して色度
の三刺激値を求めハンターの色差式により△Ｅ値
を計算した。ソーラリゼーシヨンの防止効果は、
ガラスビーズの△Ｅ値が２以下であるかどうかを
基準に判定するのが適当である。すなわち、紫外
線照射後のガラスビーズの△Ｅ値が２以下である
場合には、ソーラリゼーシヨンによる変色がほと
んど感じられず、更に再帰反射シートにした場合
には、ガラスビーズを被覆する樹脂の紫外線カツ
トの相剰効果もあつて△Ｅ値は零に近い値とな
る。
表−２に実施例と比較例の測定結果を示した。[Table] The raw material for glass should be one with particularly low impurities such as iron, and the raw material should be adjusted to the basic composition shown in Table 1 above, with Fe 2 O 3 of 0.003, 0.01,
The content of CeO 2 was adjusted to 0.03% by weight, and the CeO 2 content was 0, 0.2, and 0.3% by weight. This mixture was placed in a platinum crucible, melted in an electric furnace at 1350-1450°C for about 30 minutes, and formed into glass beads through a crushing process. After that, heat treatment is performed in an electric furnace at 700 to 710℃ for about 15 hours, and the refractive index of both No. 1 and No. 2 glasses is changed.
It was set at 2.25. Furthermore, a retroreflective sheet was made using the glass beads and used for evaluation tests. In addition, solarization was expressed as a ΔE value (color difference value), and the ΔE value was calculated using Hunter's color difference equation by determining tristimulus values of chromaticity using a color difference meter. The prevention effect of solarization is
It is appropriate to judge based on whether the ΔE value of the glass beads is 2 or less. In other words, if the ΔE value of the glass beads after irradiation with ultraviolet rays is 2 or less, there will be almost no discoloration due to solarization, and if a retroreflective sheet is used, the resin coating the glass beads will be less noticeable. Due to the mutual effect of ultraviolet rays cut, the ΔE value becomes close to zero. Table 2 shows the measurement results of Examples and Comparative Examples.
以上説明したように本発明によれば、ガラスビ
ーズを加熱処理を行つた後に紫外線照射を受けて
もソーラリゼーシヨンによる変色は極めて少な
く、再帰反射シートに使用した場合の変色問題は
全くない。
As explained above, according to the present invention, even if glass beads are heat-treated and then irradiated with ultraviolet rays, there is very little discoloration due to solarization, and there is no discoloration problem when used in a retroreflective sheet.
Claims (1)
を少くとも60重量％含み、屈折率を増加させるた
めに加熱処理をしたガラスビーズにおいて、前記
ガラスビーズ中に含まれる不純物としてのFe2O3
を0.01重量％以下におさえ、且つCeO2を0.01〜
0.5重量％添加したことを特徴とする高屈折率ガ
ラスビーズ。1. In glass beads containing at least 60% by weight of one or both of TiO 2 and BaO and heat-treated to increase the refractive index, Fe 2 O 3 as an impurity contained in the glass beads.
0.01% by weight or less, and CeO 2 from 0.01 to 0.01% by weight.
High refractive index glass beads characterized by 0.5% by weight added.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3962683A JPS59164650A (en) | 1983-03-10 | 1983-03-10 | Glass bead having high refractive index |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3962683A JPS59164650A (en) | 1983-03-10 | 1983-03-10 | Glass bead having high refractive index |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59164650A JPS59164650A (en) | 1984-09-17 |
| JPH0144657B2 true JPH0144657B2 (en) | 1989-09-28 |
Family
ID=12558309
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3962683A Granted JPS59164650A (en) | 1983-03-10 | 1983-03-10 | Glass bead having high refractive index |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59164650A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6800574B2 (en) | 2001-10-24 | 2004-10-05 | 3M Innovative Properties Company | Glass beads and uses thereof |
| JP4953234B2 (en) | 2006-09-14 | 2012-06-13 | 独立行政法人 宇宙航空研究開発機構 | Titanium-based oxide glass and method for producing the same |
| JP7488508B2 (en) * | 2019-07-17 | 2024-05-22 | 日本電気硝子株式会社 | Glass articles |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4831734A (en) * | 1971-08-24 | 1973-04-26 | ||
| JPS515316A (en) * | 1974-07-02 | 1976-01-17 | Fukuoka Tokushu Garasu Kk | SAIKIHANSHAYOKOKUTSUSETSURITSUGARASU |
-
1983
- 1983-03-10 JP JP3962683A patent/JPS59164650A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59164650A (en) | 1984-09-17 |
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