JP2019089892A - Dry process silica powder for fluorescent body, and method for manufacturing silicate fluorescent body using the silica powder - Google Patents
Dry process silica powder for fluorescent body, and method for manufacturing silicate fluorescent body using the silica powder Download PDFInfo
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本発明は、発光素子からの青色系の光を吸収し、青色系の光に対する補色光を発光可能な(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4で表される緑色ケイ酸塩蛍光体を作製するための乾式シリカ粉末及びこのシリカ粉末を用いてケイ酸塩蛍光体を製造する方法に関する。 The present invention produces a green silicate phosphor represented by (Sr, Ba, Eu) 2 SiO 4 capable of absorbing bluish light from a light emitting element and emitting complementary light to bluish light. TECHNICAL FIELD The present invention relates to a dry silica powder for the production and a method of producing a silicate phosphor using the silica powder.
従来、この種のケイ酸塩蛍光体は、例えば炭酸ストロンチウム（ＳｒＣＯ3）粉末と、炭酸バリウム（ＢａＣＯ3）粉末と、酸化ユウロピウム（Ｅｕ2Ｏ3）粉末と、シリカ（ＳｉＯ2）粉末とを十分に混合して原料粉末を作った後、この原料粉末に、フラックスとして、例えば塩化バリウム（ＢａＣｌ2）粉末を均一に混合し、混合物を還元性ガスと不活性ガスの混合ガス雰囲気下で焼成し、続いて粉砕工程、洗浄工程、乾燥工程及び篩別工程等を経て、所定の粒度にして得られる（例えば、特許文献１参照。）。即ち、上記ケイ酸塩蛍光体は固相反応により製造される。 Conventionally, this type of silicate phosphor includes, for example, strontium carbonate (SrCO 3 ) powder, barium carbonate (BaCO 3 ) powder, europium oxide (Eu 2 O 3 ) powder, and silica (SiO 2 ) powder. After sufficiently mixing to make a raw material powder, for example, barium chloride (BaCl 2 ) powder is uniformly mixed as a flux to the raw material powder, and the mixture is fired under a mixed gas atmosphere of a reducing gas and an inert gas Then, it is obtained through the grinding process, the washing process, the drying process, the sieving process and the like to obtain a predetermined particle size (see, for example, Patent Document 1). That is, the silicate phosphor is produced by solid phase reaction.
こうしたケイ酸塩系蛍光体を得るためのシリカ粉末として、サブミクロンから数μｍの粒子サイズの蛍光体の凝集に起因する蛍光体のバインダへの分散不足を解消し、蛍光体膜を形成した際の発光特性を向上させる蛍光体用シリカ粒子が提案されている（例えば、特許文献２参照。）。特許文献２には、この蛍光体用シリカ粒子が、平均粒径０．５〜１０μｍ、最大粒径２０μｍ以下、粒径０．１μｍ以下の粒子の含有率５．０体積％以下であること、その比表面積が１００ｍ2／ｇ以上であり、粒子の形状が真球度０．９以上の粒子の含有率が９０体積％以上であることが記載されている。 As a silica powder for obtaining such a silicate-based phosphor, when the insufficient dispersion of the phosphor to the binder due to the aggregation of the phosphor of particle size of submicron to several μm is eliminated to form a phosphor film The silica particle for fluorescent substance which improves the luminescent property of these is proposed (for example, refer patent document 2). In Patent Document 2, the phosphor particles for phosphors have an average particle diameter of 0.5 to 10 μm, a maximum particle diameter of 20 μm or less, and a content of particles having a particle diameter of 0.1 μm or less of 5.0 volume% or less. It is described that the specific surface area is 100 m 2 / g or more, and the content of particles having a sphericity of 0.9 or more is 90 volume% or more.
上述したように、ケイ酸塩蛍光体は、固相反応により製造するため、発光強度を高めるには、組成を均一にしてかつ不純物の含有量を少なくすることが求められている。特許文献２に示される蛍光体用シリカ粒子は、平均粒径０．５〜１０μｍ又は比表面積が１００ｍ2／ｇ以上であって、真球度が高く粒度分布がシャープである特徴を有するが、アルカリケイ酸塩水溶液と鉱酸による湿式反応で製造されるため、上記特徴だけでは、ケイ酸塩蛍光体の組成を均一にするには限界があり、発光強度の高いケイ酸塩蛍光体を得るには、まだ改善すべき余地があった。 As described above, since the silicate phosphor is manufactured by a solid phase reaction, it is required to make the composition uniform and reduce the content of impurities in order to increase the emission intensity. The silica particles for a phosphor shown in Patent Document 2 have a feature that the average particle diameter is 0.5 to 10 μm or the specific surface area is 100 m 2 / g or more, and the sphericity is high and the particle size distribution is sharp. Since it is produced by a wet reaction with an aqueous solution of an alkali silicate and a mineral acid, the above features alone have limits for making the composition of the silicate phosphor uniform, and a silicate phosphor with high emission intensity is obtained There is still room for improvement.
本発明の目的は、発光強度が高いケイ酸塩蛍光体を作製するための乾式シリカ粉末を提供することにある。本発明の別の目的は、この乾式シリカ粉末を用いてケイ酸塩蛍光体の不純物であるＢａＳｉＯ3含有量を小さくし得るケイ酸塩蛍光体の製造方法を提供することにある。 An object of the present invention is to provide a dry silica powder for producing a silicate phosphor having high emission intensity. Another object of the present invention is to provide a method for producing a silicate phosphor capable of reducing the content of BaSiO 3 which is an impurity of the silicate phosphor by using this dry silica powder.
本発明者らは、固相反応法により製造されるケイ酸塩蛍光体の発光強度を高めるには、蛍光体の組成の均一性が重要であるところ、原料として用いる高純度シリカ粉末として高い比表面積と高い嵩密度の乾式シリカ粉末を用いることにより、シリカ粉末が重くなることで他の粉末と混ざりやすくなって、原料粉末の焼成時に均一な固相反応を遂行でき、その結果高い発光強度の蛍光体が得られることを知見し、本発明に到達した。 The present inventors have found that uniformity of the composition of the phosphor is important for enhancing the emission intensity of the silicate phosphor produced by the solid phase reaction method, and the high ratio of high purity silica powder used as a raw material By using a dry silica powder having a high surface area and a high bulk density, the silica powder can be easily mixed with other powders by being heavy, and a uniform solid phase reaction can be performed at the time of firing of the raw material powder, as a result It turned out that a fluorescent substance was obtained, and reached the present invention.
本発明の第１の観点は、ＢＥＴ比表面積が９０〜５００ｍ2／ｇ、嵩密度が７０〜４００ｇ／Ｌ、純度が９９．９８７％以上、不純物であるＡｌ含有量が２０ｐｐｍ以下、Ｎａ含有量が１０ｐｐｍ以下、Ｃｌ含有量が１００ｐｐｍ以下であって、水分含有量が２％以下である蛍光体用乾式シリカ粉末である。なお、本明細書、特許請求の範囲及び要約書において、上記純度は、上記Ａｌ、Ｎａ及びＣｌの全ての不純物量を差し引いて算出することにより求めた値である。 According to a first aspect of the present invention, the BET specific surface area is 90 to 500 m 2 / g, the bulk density is 70 to 400 g / L, the purity is 99.987% or more, the Al content as impurities is 20 ppm or less, the Na content Is 10 ppm or less, the Cl content is 100 ppm or less, and the water content is 2% or less. In the present specification, claims and abstract, the above-mentioned purity is a value obtained by calculating by subtracting the amounts of all impurities of the above-mentioned Al, Na and Cl.
本発明の第２の観点は、Ｓｒ原料粉末、Ｂａ原料粉末、Ｅｕ原料粉末及び第１の観点の乾式シリカ（ＳｉＯ2）粉末を含む原料粉末と、ハロゲン化Ｂａ粉末のフラックスとを均一に混合し、この混合粉末を還元性ガスと不活性ガスの混合ガス雰囲気下で焼成することにより、(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4で表されるケイ酸塩蛍光体を製造する方法であって、前記ケイ酸塩蛍光体が、Ｘ線回折においてＢａＳｉＯ3の最高回折線強度（Ｂ）と(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4の最高回折線強度（Ａ）との比（Ｂ／Ａ）が５／１００以下であるケイ酸塩蛍光体の製造方法である。 According to a second aspect of the present invention, a raw material powder containing Sr raw material powder, Ba raw material powder, Eu raw material powder and dry silica (SiO 2 ) powder of the first aspect, and a flux of halogenated Ba powder are uniformly mixed. And baking the mixed powder in a mixed gas atmosphere of a reducing gas and an inert gas to produce a silicate phosphor represented by (Sr, Ba, Eu) 2 SiO 4. The ratio of the maximum diffraction line intensity (B) of BaSiO 3 to the maximum diffraction line intensity (A) of (Sr, Ba, Eu) 2 SiO 4 in X-ray diffraction (B / A) Is 5/100 or less.
本発明の第３の観点は、第２の観点に基づく発明であって、前記乾式シリカ粉末を他の粉末と混合する前に粉砕メディアを用いて解砕することを特徴とするケイ酸塩蛍光体の製造方法である。 A third aspect of the present invention is the invention based on the second aspect, characterized in that the silicate fluorescent is characterized in that the dry silica powder is crushed using a grinding media before mixing with other powders. It is a method of manufacturing the body.
本発明の第４の観点は、第２又は第３の観点に基づく発明であって、前記混合粉末を焼成する前にペレット化することを特徴とするケイ酸塩蛍光体の製造方法である。 A fourth aspect of the present invention is an invention based on the second or third aspect, which is a method for producing a silicate phosphor characterized in that the mixed powder is pelletized before firing.
本発明の第５の観点は、第１の観点の蛍光体用乾式シリカ粉末を用いて作製されたケイ酸塩蛍光体である。 A fifth aspect of the present invention is a silicate phosphor produced using the dry silica powder for a phosphor of the first aspect.
本発明の第１の観点に基づく発明では、蛍光体用乾式シリカ粉末がＢＥＴ比表面積が９０〜５００ｍ2／ｇ、嵩密度が７０〜４００ｇ／Ｌ、純度が９９．９８７％以上、不純物であるＡｌ含有量が２０ｐｐｍ以下、Ｎａ含有量が１０ｐｐｍ以下、Ｃｌ含有量が１００ｐｐｍ以下であって、水分含有量が２％以下であるため、発光強度が高いケイ酸塩蛍光体を作製することができる。 In the invention based on the first aspect of the present invention, the dry silica powder for phosphors has a BET specific surface area of 90 to 500 m 2 / g, a bulk density of 70 to 400 g / L, a purity of 99.987% or more, and an impurity. Since the content of Al is 20 ppm or less, the content of Na is 10 ppm or less, the content of Cl is 100 ppm or less, and the water content is 2% or less, a silicate phosphor having high emission intensity can be produced. .
本発明の第２の観点に基づく発明では、フラックスとしてハロゲン化Ｂａ粉末を用いて、(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4で表されるケイ酸塩蛍光体を製造する際に、原料粉末として第１の観点の蛍光体用シリカ粉末を用いるため、Ｘ線回折においてＢａＳｉＯ3の最高回折線強度（Ｂ）と(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4の最高回折線強度（Ａ）との比（Ｂ／Ａ）が５／１００以下である不純物の少ないケイ酸塩蛍光体を得ることができる。 In the invention based on the second aspect of the present invention, when producing a silicate phosphor represented by (Sr, Ba, Eu) 2 SiO 4 using a halogenated Ba powder as a flux, as a raw material powder In order to use the silica powder for a phosphor according to the first aspect, the ratio of the highest diffraction line intensity (B) of BaSiO 3 to the highest diffraction line intensity (A) of (Sr, Ba, Eu) 2 SiO 4 in X-ray diffraction It is possible to obtain a silicate phosphor with few impurities in which (B / A) is 5/100 or less.
本発明の第３の観点に基づく発明では、乾式シリカ粉末をボールミル等で解砕することにより、シリカ粉末の分散性と嵩密度が高められ、混合粉末の焼成時の固相反応が均一に行われ、発光強度がより高いケイ酸塩蛍光体が得られる。 In the invention based on the third aspect of the present invention, the dispersibility and bulk density of the silica powder are enhanced by crushing the dry silica powder with a ball mill or the like, and the solid phase reaction at the time of firing the mixed powder is uniform. Thus, a silicate phosphor having higher emission intensity is obtained.
本発明の第４の観点に基づく発明では、混合粉末をペレット化してから、焼成するため、焼成時により均一に原料粉末を固相反応させることができ、結果として、発光強度がより高いケイ酸塩蛍光体が得られる。 In the invention based on the fourth aspect of the present invention, since the mixed powder is pelletized and then fired, the raw material powder can be more uniformly solid phase reacted at the time of firing, and as a result, silicic acid having higher emission intensity A salt phosphor is obtained.
本発明の第５の観点に基づく発明では、第１の観点の蛍光体用シリカ粉末を用いるため、ケイ酸塩蛍光体は発光強度が高い特長がある。 In the invention based on the fifth aspect of the present invention, since the silica powder for a phosphor according to the first aspect is used, a silicate phosphor has a feature of high emission intensity.
次に本発明を実施するための形態を説明する。
〔蛍光体用乾式シリカ粉末〕
この蛍光体用乾式シリカ粉末は、ＢＥＴ法により測定される９０〜５００ｍ2／ｇの範囲の比表面積を有する。この比表面積の範囲のシリカ粉末は、Ｓｒ原料粉末、Ｂａ原料粉末及びＥｕ原料粉末などの他の粉末（以下、単に「他の粉末」という。）と混合した後の焼成時に、粒径が小さいため、他の粉末との反応性がよく、蛍光体の組成が均一になる。比表面積がこの範囲の下限値未満のシリカ粉末は、他の粉末と混合した後の焼成時に反応性が悪く、均一な固相反応が遂行しない。また上限値を超えると、シリカ粉末が他の粉末と均一に混ざらなくなる。この比表面積から計算される蛍光体用乾式シリカ粉末の一次粒子径は約５〜２５ｎｍの範囲にあり、好ましくは５〜１５ｎｍの範囲にある。好ましい蛍光体用乾式シリカ粉末のＢＥＴ法による比表面積は２００〜５００ｍ2／ｇの範囲である。
Next, an embodiment of the present invention will be described.
Dry silica powder for phosphors
The dry silica powder for a phosphor has a specific surface area in the range of 90 to 500 m 2 / g as measured by the BET method. The silica powder in this specific surface area range has a small particle size at the time of firing after mixing with other powders (hereinafter, simply referred to as "other powders") such as Sr raw material powder, Ba raw material powder and Eu raw material powder. Therefore, the reactivity with other powders is good, and the composition of the phosphor becomes uniform. Silica powders having a specific surface area less than the lower limit of this range have poor reactivity at the time of firing after mixing with other powders, and uniform solid phase reaction is not performed. If the upper limit is exceeded, the silica powder will not mix uniformly with other powders. The primary particle diameter of the dry silica powder for phosphors calculated from this specific surface area is in the range of about 5 to 25 nm, preferably in the range of 5 to 15 nm. The specific surface area by BET method of the preferable dry silica powder for phosphors is in the range of 200 to 500 m 2 / g.
またこの蛍光体用乾式シリカ粉末は、７０〜４００ｇ／Ｌの嵩密度を有する。シリカ粉末がこの範囲の嵩密度を有すると、シリカ粉末が適度に重くなって、他の粉末と混ざりやすくなる。嵩密度がこの範囲の下限値未満では、他の粉末と混合するときにシリカ粉末が軽すぎて他の粉末と均一に混ざり合わなくなる。上限値を超えると、シリカ粉末が凝集体になり易く、この場合も他の粉末と均一に混ざり合わなくなる。好ましい蛍光体用乾式シリカ粉末の嵩密度は１３０〜４００ｇ／Ｌの範囲にある。 Moreover, this dry-type silica powder for fluorescent substance has a bulk density of 70-400 g / L. When the silica powder has a bulk density in this range, the silica powder becomes moderately heavy and easily mixes with other powders. When the bulk density is less than the lower limit of this range, the silica powder is too light when mixed with other powders and does not mix uniformly with other powders. If the upper limit is exceeded, the silica powder tends to be agglomerated, and again in this case, it does not mix uniformly with other powders. The bulk density of the preferred phosphor-use dry silica powder is in the range of 130 to 400 g / L.
またこの蛍光体用乾式シリカ粉末は、不純物であるＡｌ含有量が２０ｐｐｍ以下、Ｎａ含有量が１０ｐｐｍ以下、Ｃｌ含有量が１００ｐｐｍ以下であり、それから算出される純度が９９．９８７％以上である。Ａｌ、Ｎａ、Ｃｌは乾式シリカ粉末の製造過程で不可避的に含まれる不純物である。純度が９９．９８７％未満であるか、Ａｌ含有量が２０ｐｐｍを超えるか、Ｎａ含有量が１０ｐｐｍを超えるか、又はＣｌ含有量が１００ｐｐｍを超えると、シリカ粉末を用いてケイ酸塩蛍光体を作製したときに、ケイ酸塩蛍光体の不純物の含有量が多くなり、その発光効率が低下し、結果的にケイ酸塩蛍光体の発光強度が低下する。好ましい蛍光体用乾式シリカ粉末は、不純物であるＡｌ含有量が３ｐｐｍ以下、Ｎａ含有量が１ｐｐｍ以下、Ｃｌ含有量が８０ｐｐｍ以下であり、それから算出される純度が９９．９９２％以上である。 The dry silica powder for a phosphor has an Al content of 20 ppm or less as an impurity, a Na content of 10 ppm or less, a Cl content of 100 ppm or less, and a purity calculated therefrom of 99.987% or more. Al, Na and Cl are impurities which are inevitably contained in the process of producing the dry silica powder. If the purity is less than 99.987%, the Al content is more than 20 ppm, the Na content is more than 10 ppm, or the Cl content is more than 100 ppm, the silicate phosphor is When produced, the content of impurities in the silicate phosphor increases, the luminous efficiency thereof decreases, and as a result, the luminous intensity of the silicate phosphor decreases. The preferable dry silica powder for a phosphor has an Al content of 3 ppm or less as an impurity, a Na content of 1 ppm or less, a Cl content of 80 ppm or less, and a purity calculated therefrom of 99.992% or more.
更にこの蛍光体用乾式シリカ粉末は、２％以下の水分含有量（シリカ粉末に含まれる水分質量％）を有するのが好ましい。ケイ酸塩蛍光体は、Ｓｒ原料粉末、Ｂａ原料粉末、Ｅｕ原料粉末等の固相反応により作製されるので、この蛍光体用乾式シリカ粉末の水分含有量が２％を超えると、加熱により大きな重量減が生じるため化学量論比がずれて所望化学量論比の有した蛍光体を作製するのが困難になる等の問題がある。更に好ましくは蛍光体用乾式シリカ粉末の水分含有量は１％以下である。 Furthermore, the dry silica powder for a phosphor preferably has a water content (mass% of water contained in the silica powder) of 2% or less. Since silicate phosphors are produced by solid-phase reaction of Sr raw material powder, Ba raw material powder, Eu raw material powder etc., when the water content of this dry silica powder for phosphors exceeds 2%, it is large by heating Since weight loss occurs, there is a problem that the stoichiometry ratio shifts and it becomes difficult to produce a phosphor having a desired stoichiometry ratio. More preferably, the water content of the dry silica powder for phosphor is 1% or less.
〔蛍光体用乾式シリカ粉末の製造方法〕
本発明の蛍光体用乾式シリカ粉末は、ケイ素ハロゲン化合物の蒸気相酸化による乾式法（又は気相法）で生成される。特に、乾式シリカ粉末としては、四塩化ケイ素等のケイ素化合物や金属ケイ素を火炎中、例えば酸水素火炎中で加水分解して製造される（噴霧火炎法で製造される）ヒュームドシリカが、溶媒を使用せず、乾燥時に凝集粒子を生成しないため、好ましい。本発明のシリカ粉末は、共沈法、水熱反応法、ゾルゲル法で生成される湿式シリカ粉末や、結晶性シリカを溶融する方法で生成された溶融式シリカ粉末を含まない。湿式シリカ粉末は、金属不純物が多く、これが蛍光体を作製したときに不純物になり、蛍光体の発光強度が低下するからである。また湿式シリカ粉末は、シラノール基が多く、蛍光体の作製時に水分を発生させるために反応性が低下する。またゾルゲル法で生成される湿式シリカ粉末は、水分含有量が多く、かつ水分散液から乾燥して得られるため、所望の平均粒径の一次粒子径にならない。溶融式シリカ粉末は比表面積が小さいため反応性が悪くなる不具合がある。
[Method of producing dry silica powder for phosphor]
The dry silica powder for phosphor of the present invention is produced by a dry method (or a gas phase method) by vapor phase oxidation of a silicon halogen compound. In particular, as the dry silica powder, fumed silica (produced by the spray flame method) produced by hydrolyzing a silicon compound such as silicon tetrachloride or metallic silicon in a flame, for example, in an oxyhydrogen flame, is a solvent It is preferable because it does not use and does not form agglomerated particles upon drying. The silica powder of the present invention does not contain wet silica powder produced by coprecipitation method, hydrothermal reaction method, sol-gel method, or fused silica powder produced by a method of melting crystalline silica. The wet silica powder contains many metal impurities, which become impurities when the phosphor is produced, and the emission intensity of the phosphor decreases. In addition, the wet silica powder has many silanol groups, and the reactivity is reduced because moisture is generated at the time of preparation of the phosphor. In addition, since the wet silica powder produced by the sol-gel method has a high water content and is obtained by drying from an aqueous dispersion, it does not have a desired primary particle size of the average particle size. Since the fused silica powder has a small specific surface area, there is a problem that the reactivity is deteriorated.
乾式法で得られたシリカ粉末をそのまま蛍光体用乾式シリカ粉末とすることもできるが、粉砕メディアを用いて解砕することにより分散性と嵩密度を高めた蛍光体用乾式シリカ粉末を利用することが好ましい。粉砕メディアを用いた解砕方法の場合、一般的に乾式シリカ粉末の嵩密度を高めることが可能である。粉砕メディアとしては、特に限定されないが、一例として、ボールが挙げられる。解砕はミル回転速度、解砕時間、ボール径を調整することにより行われる。ここで用いるボールとしては、一般的に使用されるものであれば良く、特に限定はされないが、アルミナボール、ジルコニアボール、ＳｉＣボール等が挙げられる。粉砕メディアを用いない解砕としてジェットミルがあるが、このジェットミルにより解砕すると、嵩密度が低くなるため、ジェットミルは本発明の蛍光体用乾式シリカ粉末の製造には不適である。解砕前と解砕後で嵩密度を１．８倍以上に高めることが好ましい。嵩密度を１．８倍以上に高密度化することにより、蛍光体の発光強度を１．１倍以上に高めることができる。 The silica powder obtained by the dry method can be used as it is as a dry silica powder for a phosphor, but it is used a dry silica powder for a phosphor whose dispersibility and bulk density are enhanced by crushing using a grinding media. Is preferred. In the case of a crushing method using a grinding media, it is generally possible to increase the bulk density of the dry silica powder. There is no particular limitation on the grinding media, but one example is balls. Crushing is performed by adjusting the rotation speed of the mill, the crushing time, and the ball diameter. The ball used here is not particularly limited as long as it is generally used, and examples thereof include alumina balls, zirconia balls, SiC balls and the like. Although there is a jet mill as a disintegration without using a grinding media, the disintegration by this jet mill lowers the bulk density, so the jet mill is not suitable for producing the dry silica powder for phosphor of the present invention. It is preferable to increase the bulk density 1.8 times or more before and after crushing. By densifying the bulk density to 1.8 times or more, the emission intensity of the phosphor can be increased to 1.1 times or more.
〔ケイ酸塩蛍光体の製造方法〕
本発明のケイ酸塩蛍光体を製造するには、まず、ストロンチウム（Ｓｒ）の原料粉末として例えば炭酸ストロンチウム（ＳｒＣＯ3）粉末と、バリウム（Ｂａ）の原料粉末として例えば炭酸バリウム（ＢａＣＯ3）粉末と、ユウロピウム（Ｅｕ）の原料粉末として例えば酸化ユウロピウム（Ｅｕ2Ｏ3）粉末と、ケイ素（Ｓｉ）の原料粉末として、上述した乾式シリカ（ＳｉＯ2）粉末とを所望の質量割合で均一に混合して原料粉末を調製する。シリカ粉末以外の原料粉末、即ち他の粉末は、炭酸塩に限らず、焼成時に酸化物に変化する化合物でもよい。上記粉末の混合割合は、各元素の元素比（モル比）として、アルカリ土類金属とユウロピウムのモル数の合計が、ケイ素のモル数の２倍を超える比率、すなわち化学量論比である２を超えて、２．０２〜２．０８の範囲にあることが好ましく、２．０２４〜２．０５の範囲がより好ましい。
[Method of producing silicate phosphor]
In order to produce the silicate phosphor of the present invention, first, for example, strontium carbonate (SrCO 3 ) powder as a raw material powder of strontium (Sr) and barium carbonate (BaCO 3 ) powder as a raw material powder of barium (Ba) And, for example, europium oxide (Eu 2 O 3 ) powder as a raw material powder of europium (Eu) and the above-mentioned dry silica (SiO 2 ) powder as a raw material powder of silicon (Si) uniformly mixed in a desired mass ratio The raw material powder is prepared. The raw material powder other than the silica powder, that is, the other powder, is not limited to the carbonate, and may be a compound that changes to an oxide upon firing. The mixing ratio of the above powder is a ratio of the total of the number of moles of alkaline earth metal and europium over twice the number of moles of silicon, that is, the stoichiometric ratio as the element ratio (molar ratio) of each element Is preferably in the range of 2.02 to 2.08, and more preferably in the range of 2.024 to 2.05.
他の粉末の固相反応を促進するフラックスとしては、塩化バリウム（ＢａＣｌ2）といったアルカリ土類金属のハロゲン化物を用いることができる。塩化アンモニウム（ＮＨ4Ｃｌ）といったハロゲン化物等を用いてもよい。フラックスの添加量としては原料粉末質量の１ないし４％程度が好ましい。 As a flux that promotes solid-phase reaction of other powders, halides of alkaline earth metals such as barium chloride (BaCl 2 ) can be used. A halide such as ammonium chloride (NH 4 Cl) may be used. The addition amount of the flux is preferably about 1 to 4% of the mass of the raw material powder.
こうしてＳｒ原料粉末、Ｂａ原料粉末、Ｅｕ原料粉末、本発明の乾式シリカ粉末、ハロゲン化Ｂａ粉末を混合した混合粉末を焼成する。焼成前に混合粉末を所定の型に入れ、２５ＭＰａ以上、好ましくは３０ＭＰａの圧力を加えてペレットにすることが好ましい。ペレット化することにより、焼成時、より均一に原料粉末を固相反応させ、蛍光体の発光強度を高めることができる。ペレット化せずに粉末のままで焼成した場合、原料乾式シリカ粉末が所定範囲の嵩密度、純度等を有していてもペレット化した場合に比較して高い輝度を得ることができない。この理由は定かではないが、ペレット化することにより原料粉末同士の接触が良く密になることにより固相反応がより均一に進行するためであると推察される。焼成は、上記混合粉末を１２５０〜１４５０℃の温度範囲、好ましくは１３２０〜１３７０℃の温度範囲にて、４〜１２時間、好ましくは６〜１０時間、還元性ガスと不活性ガスの混合ガス雰囲気下で、行う。還元性ガスとしてはＨ2、ＣＯ等のガスが、不活性ガスとしてはＮ2、Ａｒ、Ｈｅ、Ｘｅ等のガスが挙げられる。混合ガス中、還元性ガスは２〜９体積％であることが好ましく、３〜７体積％であることが更に好ましい。焼成を行った後、焼成体を粉砕することにより、所定の粒度の緑色ケイ酸塩蛍光体が得られる。 Thus, the mixed powder obtained by mixing the Sr raw material powder, the Ba raw material powder, the Eu raw material powder, the dry silica powder of the present invention, and the halogenated Ba powder is fired. It is preferable to put the mixed powder in a predetermined mold before firing and apply a pressure of 25 MPa or more, preferably 30 MPa to form pellets. By pelletizing, the raw material powder can be more uniformly solid phase reacted at the time of firing, and the emission intensity of the phosphor can be increased. If the raw material dry silica powder is fired in the form of powder without pelletization, even if the raw material dry silica powder has a bulk density, purity, etc. within a predetermined range, high brightness can not be obtained as compared to the case of pelletization. The reason for this is not clear, but it is presumed that the solid phase reaction proceeds more uniformly due to the contact between the raw material powders becoming well and dense by pelletizing. In the mixed powder, a mixed gas atmosphere of a reducing gas and an inert gas in the temperature range of 1250 to 1450 ° C., preferably in the temperature range of 1320 to 1370 ° C. for 4 to 12 hours, preferably 6 to 10 hours. Do it below. Examples of the reducing gas include gases such as H 2 and CO, and examples of the inert gas include gases such as N 2 , Ar, He, and Xe. In the mixed gas, the reducing gas is preferably 2 to 9% by volume, and more preferably 3 to 7% by volume. After firing, the fired body is pulverized to obtain a green silicate phosphor of a predetermined particle size.
〔ケイ酸塩蛍光体〕
得られた蛍光体の組成は、(ＳｒxＢａyＥｕ1-x-y)2ＳｉＯ4で表される。ここで、０．０１≦ｘ≦０．９８、０．０１≦ｙ≦０．９８、０．７０＜（ｘ＋ｙ）＜０．９９、好ましくは０．０５≦ｘ≦０．９５、０．０５≦ｙ≦０．９５、０．８０＜（ｘ＋ｙ）＜０．９８である。得られたケイ酸塩蛍光体で固相反応が均一に行われたかを確認するために、ケイ酸塩蛍光体をＸ線回折し、不純物であるＢａＳｉＯ3と得られたケイ酸塩蛍光体について、それぞれ最高強度ピークを求める。ＢａＳｉＯ3の最高回折線強度（Ｂ）と(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4の最高回折線強度（Ａ）との比（Ｂ／Ａ）が５／１００以下であることが必要である。好ましくは１／１００以下である。
[Silicate phosphor]
The composition of the resulting phosphor is represented by (Sr x Ba y Eu 1- xy) 2 SiO 4. Here, 0.01 ≦ x ≦ 0.98, 0.01 ≦ y ≦ 0.98, 0.70 <(x + y) <0.99, preferably 0.05 ≦ x ≦ 0.95, 0.05 It is ≦ y ≦ 0.95 and 0.80 <(x + y) <0.98. In order to confirm whether the solid phase reaction was uniformly carried out with the obtained silicate phosphor, the silicate phosphor was subjected to X-ray diffraction, and about the impurity BaSiO 3 and the obtained silicate phosphor , Find the highest intensity peak respectively. The ratio (B / A) of the highest diffraction line intensity (B) of BaSiO 3 to the highest diffraction line intensity (A) of (Sr, Ba, Eu) 2 SiO 4 is required to be 5/100 or less. Preferably it is 1/100 or less.
次に本発明の実施例を比較例とともに詳しく説明する。 Next, an example of the present invention will be described in detail along with a comparative example.
＜実施例１＞
乾式シリカ粉末として、ＢＥＴ比表面積が２００ｍ2／ｇ、嵩密度が４５ｇ／Ｌ、純度が９９．８％、不純物であるＡｌ含有量が２ｐｐｍ、Ｎａ含有量が１ｐｐｍ、Ｃｌ含有量が７０ｐｐｍ以下であって、水分含有量が０．３％のヒュームドシリカ（商品名AEROSIL(登録商標)200、日本アエロジル社製）を用意した。この乾式シリカ粉末を直径１５ｍｍのアルミナボールの入ったボールミル（増田理化工業社製Universal Ball Mill UBM-S）を用いて室温で６０ｒｐｍの回転速度で９０分間、解砕して嵩密度を１３６ｇ／Ｌに高めた後、この乾式シリカ粉末０．３６７ｇ(０．９７６モル)と、ＳｒＣＯ3粉末（レアメタリック社製、純度：９９．９％）０．８４０ｇ(０．９１モル)と、ＢａＣＯ3粉末（添川理化学社製、純度：９９．９％）１．１７２ｇ(０．９５モル)と、Ｅｕ2Ｏ3粉末（レアメタリック社製、純度：９９．９％）０．１６７ｇ(０．１４モル)と、フラックスとしてＢａＣｌ4粉末（シグマアルドリッチ社製、純度：９９．９％）０．０２５ｇとをエタノール中で瑪瑙乳鉢でエタノールが蒸発するまで最低でも１５分間以上粉砕混合し、再度瑪瑙乳鉢にエタノールを入れて同様に粉砕混合を繰り返し、均一に混合した原料粉末を作製した。
Example 1
The dry silica powder has a BET specific surface area of 200 m 2 / g, a bulk density of 45 g / L, a purity of 99.8%, an Al content of 2 ppm as impurities, a Na content of 1 ppm, and a Cl content of 70 ppm or less A fumed silica (trade name: AEROSIL (registered trademark) 200, manufactured by Nippon Aerosil Co., Ltd.) having a water content of 0.3% was prepared. This dry silica powder is crushed at a rotational speed of 60 rpm for 90 minutes at room temperature using a ball mill (Universal Ball Mill UBM-S manufactured by Masuda Rika Kogyo Co., Ltd.) containing alumina balls with a diameter of 15 mm to obtain a bulk density of 136 g / L Of the dry silica powder, 0.840 g (0.91 mol) of SrCO 3 powder (raer metallic company, purity: 99.9%), and BaCO 3 powder. (Soekawa Chemical Co., Ltd., purity: 99.9%) 1.172 g (0.95 mol) and Eu 2 O 3 powder (rare metallic, product purity: 99.9%) 0.167 g (0.14 mol) a), BaCl 4 powder (manufactured by sigma-Aldrich as a flux, purity: 99.9%) and 0.025g ground and mixed over 15 minutes at least to ethanol in an agate mortar with ethanol evaporates, the agate mortar again Repeat pulverized and mixed similarly put ethanol, to prepare a raw material powder were uniformly mixed.
この混合粉末を直径１５ｍｍ、深さ４０ｍｍのペレット成型器に入れ、３０ＭＰａの圧力を加えてペレットにした。このペレットを水素ガスと窒素ガスの混合ガス（水素ガス：５体積％）雰囲気下、１３４０℃で８時間焼成した。焼成後、ペレットを乳鉢で粉砕してケイ酸塩蛍光体を得た。この蛍光体の組成はＳｒ0.46，Ｂａ0.48，Ｅｕ0.06)2ＳｉＯ4であった。本ケイ酸塩蛍光体の作製に用いた乾式シリカ粉末の性状を表１に示し、シリカ粉末の解砕（高密度化処理）の有無、その解砕条件、ペレット化の有無、不純物残渣の割合及び得られた蛍光体粉末の発光強度を表２に示す。 The mixed powder was placed in a pelletizer having a diameter of 15 mm and a depth of 40 mm, and a pressure of 30 MPa was applied to form pellets. The pellets were fired at 1340 ° C. for 8 hours in a mixed gas of hydrogen gas and nitrogen gas (hydrogen gas: 5% by volume) atmosphere. After firing, the pellets were crushed in a mortar to obtain a silicate phosphor. The composition of this phosphor was Sr 0.46 , Ba 0.48 , Eu 0.06 ) 2 SiO 4 . The properties of the dry silica powder used in the preparation of the present silicate phosphor are shown in Table 1, and the presence or absence of crushing (densification treatment) of the silica powder, the crushing conditions, the presence or absence of pelletization, and the proportion of impurity residue And the luminescence intensity of the obtained phosphor powder is shown in Table 2.
＜実施例２＞
乾式シリカ粉末として、表１の性状を有するヒュームドシリカ（商品名AEROSIL(登録商標)90G、日本アエロジル社製）を用意した。この乾式シリカ粉末を６０ｒｐｍの回転速度で９０分間解砕した以外、実施例１と同様に解砕して、嵩密度を５９ｇ／Ｌから１９０ｇ／Ｌに高めた。実施例１と異なり、混合粉末のペレット化はしなかった。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Example 2
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 90G, manufactured by Nippon Aerosil Co., Ltd.) having the properties shown in Table 1 was prepared. The dry silica powder was crushed in the same manner as in Example 1 except that the dry silica powder was broken at a rotational speed of 60 rpm for 90 minutes to increase the bulk density from 59 g / L to 190 g / L. Unlike Example 1, the mixed powder was not pelletized. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜実施例３＞
乾式シリカ粉末として、表１の性状を有するヒュームドシリカ（商品名AEROSIL(登録商標)130、日本アエロジル社製）を用意した。この乾式シリカ粉末を６０ｒｐｍの回転速度で１２０分間解砕した以外、実施例１と同様に解砕して、嵩密度を４２ｇ／Ｌから１６９ｇ／Ｌに高めた。混合粉末のペレット化はしなかった。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Example 3
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 130, manufactured by Nippon Aerosil Co., Ltd.) having the properties shown in Table 1 was prepared. The dry silica powder was crushed in the same manner as in Example 1 except that the dry silica powder was crushed at a rotational speed of 60 rpm for 120 minutes to increase the bulk density from 42 g / L to 169 g / L. There was no pelletization of the mixed powder. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜実施例４＞
乾式シリカ粉末として、表１の性状を有するヒュームドシリカ（商品名AEROSIL(登録商標)300、日本アエロジル社製）を用意した。この乾式シリカ粉末を４０ｒｐｍの回転速度で２４０分間解砕した以外、実施例１と同様に解砕して、嵩密度を４６ｇ／Ｌから１３２ｇ／Ｌに高めた。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Example 4
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 300, manufactured by Nippon Aerosil Co., Ltd.) having the properties shown in Table 1 was prepared. The dry silica powder was crushed in the same manner as in Example 1 except that the dry silica powder was crushed at a rotational speed of 40 rpm for 240 minutes to increase the bulk density from 46 g / L to 132 g / L. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜実施例５＞
乾式シリカ粉末として、表１の性状を有する実施例４と同種のヒュームドシリカ（商品名AEROSIL(登録商標)300、日本アエロジル社製）を用意した。この乾式シリカ粉末を１００ｒｐｍの回転速度で１８０分間解砕した以外、実施例１と同様に解砕して、嵩密度を４６ｇ／Ｌから３８０ｇ／Ｌに高めた。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Example 5
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 300, manufactured by Nippon Aerosil Co., Ltd.) of the same type as in Example 4 having the properties shown in Table 1 was prepared. The dry silica powder was crushed in the same manner as in Example 1 except that the dry silica powder was broken at a rotational speed of 100 rpm for 180 minutes to increase the bulk density from 46 g / L to 380 g / L. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜実施例６＞
乾式シリカ粉末として、表１の性状を有するヒュームドシリカ（商品名AEROSIL(登録商標)380、日本アエロジル社製）を用意した。この乾式シリカ粉末を６０ｒｐｍの回転速度で１２０分間解砕した以外、実施例１と同様に解砕して、嵩密度を２９ｇ／Ｌから１６０ｇ／Ｌに高めた。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Example 6
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 380, manufactured by Nippon Aerosil Co., Ltd.) having the properties shown in Table 1 was prepared. The dry silica powder was crushed in the same manner as in Example 1 except that the dry silica powder was crushed at a rotational speed of 60 rpm for 120 minutes to increase the bulk density from 29 g / L to 160 g / L. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜実施例７＞
乾式シリカ粉末として、表１の性状を有するヒュームドシリカ（試作品）を用意した。この乾式シリカ粉末を６０ｒｐｍの回転速度で６０分間解砕した以外、実施例１と同様に解砕して、嵩密度を３５ｇ／Ｌから１３０ｇ／Ｌに高めた。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Example 7
As a dry silica powder, fumed silica (prototype) having the properties of Table 1 was prepared. The dry silica powder was crushed in the same manner as in Example 1 except that the dry silica powder was broken at a rotational speed of 60 rpm for 60 minutes to increase the bulk density from 35 g / L to 130 g / L. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜実施例８＞
乾式シリカ粉末として、表１の性状を有する実施例１と同種のヒュームドシリカ（商品名AEROSIL(登録商標)200、日本アエロジル社製）を用意した。この乾式シリカ粉末の嵩密度は７９ｇ／Ｌであった。実施例１と異なり、この乾式シリカ粉末を解砕することなく、また混合粉末のペレット化もしなかった。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Example 8
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 200, manufactured by Nippon Aerosil Co., Ltd.) of the same type as in Example 1 having the properties shown in Table 1 was prepared. The bulk density of this dry silica powder was 79 g / L. Unlike Example 1, this dry silica powder was not crushed and the mixed powder was not pelletized. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜実施例９＞
乾式シリカ粉末として、表１の性状を有する実施例２と同種のヒュームドシリカ（商品名AEROSIL(登録商標)90G、日本アエロジル社製）を用意した。この乾式シリカ粉末を１００ｒｐｍの回転速度で１２０分間解砕した以外、実施例１と同様に解砕して、嵩密度を３５ｇ／Ｌから１３０ｇ／Ｌに高めた。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Example 9
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 90G, manufactured by Nippon Aerosil Co., Ltd.) of the same type as in Example 2 having the properties of Table 1 was prepared. The dry silica powder was crushed in the same manner as in Example 1 except that the dry silica powder was crushed at a rotational speed of 100 rpm for 120 minutes to increase the bulk density from 35 g / L to 130 g / L. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜比較例１＞
乾式シリカ粉末として、表１の性状を有するヒュームドシリカ（商品名AEROSIL(登録商標)50、日本アエロジル社製）を用意した。この乾式シリカ粉末の嵩密度は５８ｇ／Ｌであった。実施例１と異なり、この乾式シリカ粉末は解砕しなかった。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Comparative Example 1
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 50, manufactured by Nippon Aerosil Co., Ltd.) having the properties shown in Table 1 was prepared. The bulk density of this dry silica powder was 58 g / L. Unlike Example 1, this dry silica powder was not crushed. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜比較例２＞
乾式シリカ粉末として、表１の性状を有する実施例１と同種のヒュームドシリカ（商品名AEROSIL(登録商標)200、日本アエロジル社製）を用意した。この乾式シリカ粉末の嵩密度は５５ｇ／Ｌであった。実施例１と異なり、この乾式シリカ粉末は解砕しなかった。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Comparative Example 2
As a dry silica powder, fumed silica (trade name: AEROSIL (registered trademark) 200, manufactured by Nippon Aerosil Co., Ltd.) of the same type as in Example 1 having the properties shown in Table 1 was prepared. The bulk density of this dry silica powder was 55 g / L. Unlike Example 1, this dry silica powder was not crushed. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜比較例３＞
シリカ粉末として、テトラエトキシシランを加水分解して、ろ過した後、乾燥して、ゾルゲル法で製造された表１の性状を有するシリカ粉末を作製した。このゾルゲルシリカ粉末の嵩密度は１４３ｇ／Ｌであった。実施例１と異なり、このゾルゲルシリカ粉末は解砕しなかった。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Comparative Example 3
As a silica powder, tetraethoxysilane was hydrolyzed, filtered and then dried to prepare a silica powder having the properties of Table 1 produced by the sol-gel method. The bulk density of this sol-gel silica powder was 143 g / L. Unlike Example 1, this sol-gel silica powder was not crushed. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜比較例４＞
シリカを溶融する法で製造された表１の性状を有する溶融式シリカ粉末（ELSIL B030、日本アエロジル社製）を用意した。この溶融式シリカ粉末の嵩密度は9００ｇ／Ｌであった。実施例１と異なり、この溶融式シリカ粉末は解砕しなかった。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Comparative Example 4
A fused silica powder (ELSIL B030, manufactured by Nippon Aerosil Co., Ltd.) having the properties of Table 1 manufactured by a method of melting silica was prepared. The bulk density of this fused silica powder was 900 g / L. Unlike Example 1, this fused silica powder was not crushed. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜比較例５＞
乾式シリカ粉末として、表１の性状を有する実施例４と同種のヒュームドシリカを製造時の脱酸工程を変更し、塩素含有量の高い比表面積３００ｍ2／ｇの試作品を用意した。この乾式シリカ粉末を６０ｒｐｍの回転速度で６０分間解砕した以外、実施例１と同様に解砕して、嵩密度を４７ｇ／Ｌから１５５ｇ／Ｌに高めた。またこの乾式シリカ粉末は実施例４のシリカ粉末と異なり、Ｃｌの含有量が１０１ｐｐｍと高かった。それ以外は、実施例１と同様にしてケイ酸塩蛍光体を得た。
Comparative Example 5
As the dry silica powder, the same deoxidizing step in production of the same fumed silica as in Example 4 having the properties of Table 1 was changed to prepare a prototype with a high chlorine content and a specific surface area of 300 m 2 / g. The dry silica powder was crushed in the same manner as in Example 1 except that the dry silica powder was broken at a rotational speed of 60 rpm for 60 minutes to increase the bulk density from 47 g / L to 155 g / L. Further, unlike the silica powder of Example 4, this dry silica powder had a high content of Cl of 101 ppm. A silicate phosphor was obtained in the same manner as in Example 1 except the above.
＜比較試験及び評価＞
実施例１〜９及び比較例１〜５で用いた１４種類のシリカ粉末のＢＥＴ比表面積、嵩密度、純度、不純物（Ａｌ、Ｎａ、Ｃｌ）含有量及び水分含有量を次の方法により求めた。また実施例１〜９及び比較例１〜６で得られた１４種類のケイ酸塩蛍光体に残存する不純物と、蛍光体の発光強度を次の方法により求めた。これらの結果を表１に示す。
<Comparison test and evaluation>
The BET specific surface area, bulk density, purity, impurity (Al, Na, Cl) content and water content of the 14 types of silica powders used in Examples 1 to 9 and Comparative Examples 1 to 5 were determined by the following method. . Further, the impurities remaining in the 14 types of silicate phosphors obtained in Examples 1 to 9 and Comparative Examples 1 to 6 and the emission intensities of the phosphors were determined by the following method. The results are shown in Table 1.
（１）シリカ粉末のＢＥＴ比表面積
シリカ粉末のＢＥＴ比表面積は、ＢＥＴ比表面積測定装置（Macsorb; HM Model-1210, マウンテック社製）を用いて、シリカ粉末の表面に占有面積が既知の窒素分子を吸着させ、脱気を１６０℃で１０分の条件にしてこの窒素分子の吸着量からシリカ粉末の表面積を求める気相吸着法により測定した。
(1) BET specific surface area of silica powder The BET specific surface area of silica powder is determined by using a BET specific surface area measuring device (Macsorb; HM Model-1210, manufactured by Mountech Co., Ltd.). Were adsorbed and degassing was carried out at 160 ° C. for 10 minutes, and the surface area of the silica powder was determined from the adsorbed amount of nitrogen molecules by a gas phase adsorption method.
（２）シリカ粉末の嵩密度
シリカ粉末の嵩密度は、２５０ｍＬのメスシリンダーにシリカ粉末を所定量入れ、２分間静置後の容積（単位：リットル）で除算することにより求めた。
(2) Bulk density of silica powder The bulk density of silica powder was determined by putting a predetermined amount of silica powder in a 250 mL graduated cylinder and dividing by the volume (unit: liter) after standing for 2 minutes.
（３）シリカ粉末の純度
シリカ粉末の純度は、次に述べる不純物の測定方法で検出した値を差し引いて算出することにより求めた。
(3) Purity of Silica Powder The purity of the silica powder was determined by subtracting the value detected by the method of measuring impurities described below.
（４）シリカ粉末の不純物（Ａｌ、Ｎａ、Ｃｌ）含有量
シリカ粉末の不純物のうち、Ａｌ、Ｎａの含有量については、シリカ粉末をＩＣＰ発光分光分析装置（iCAP-6500：サーモフィッシャーサイエンティフィク社製）を用いて分析した。またＣｌの含有量についてはイオンクロマトグラム(ICS-1100：サーモフィッシャーサイエンティフィク社製)を用いて分析した。
(4) Impurities (Al, Na, Cl) Content of Silica Powder Among the impurities of the silica powder, the contents of Al and Na are the same as those of the silica powder in the ICP emission spectrum analyzer (iCAP-6500: Thermo Fisher Scientific) Company analysis). Further, the content of Cl was analyzed using an ion chromatogram (ICS-1100: manufactured by Thermo Fisher Scientific Co., Ltd.).
（５）シリカ粉末の水分含有量
シリカ粉末の水分含有量は、１００℃で３０分間乾燥して前処理した後、１０５℃で２時間乾燥させてから、その乾燥減量により測定した。
(5) Moisture Content of Silica Powder The moisture content of the silica powder was measured by drying loss after drying at 100 ° C. for 30 minutes and then pretreatment at 105 ° C. for 2 hours.
（６）ケイ酸塩蛍光体中の不純物残渣
ケイ酸塩蛍光体をＸ線回折装置（RINT2100、リガク社製）を用いて、不純物であるＢａＳｉＯ3とケイ酸塩蛍光体である(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4の各最高回折線強度を測定した。ＢａＳｉＯ3の最高回折線強度（Ｂ）と(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4の最高回折線強度（Ａ）からＸ線ピーク強度比（Ｂ／Ａ）を算出した。このＸ線ピーク強度比からケイ酸塩蛍光体中の不純物残渣が求められ、固相反応が均一に行われたか確認できる。
(6) Impurity Residues in Silicate Phosphor The silicate phosphor is an impurity BaSiO 3 and a silicate phosphor using an X-ray diffractometer (RINT 2100, manufactured by Rigaku Corporation) (Sr, Ba , Eu) 2 SiO 4 maximum diffraction line intensities were measured. The X-ray peak intensity ratio (B / A) was calculated from the highest diffraction line intensity (B) of BaSiO 3 and the highest diffraction line intensity (A) of (Sr, Ba, Eu) 2 SiO 4 . From the X-ray peak intensity ratio, the impurity residue in the silicate phosphor is determined, and it can be confirmed whether the solid phase reaction has been uniformly performed.
（７）ケイ酸塩蛍光体の発光強度
ケイ酸塩蛍光体０．４ｇを試料として、試料ホルダーに詰めて、分光光度計（FP-6500、日本分光社製）を用いて、Ｘｅランプで波長３２０ｎｍの励起光を照射し、励起バンド幅５ｎｍ、蛍光バンド幅１ｎｍの条件で測定した。各試料を比較した発光強度は発光スペクトルの最大強度である波長５２３ｎｍの強度である。
(7) Emission intensity of silicate fluorescent substance 0.4 g of silicate fluorescent substance is used as a sample and packed in a sample holder, and the wavelength is measured with a Xe lamp using a spectrophotometer (FP-6500, manufactured by JASCO Corporation) Excitation light of 320 nm was irradiated, and measurement was performed under the conditions of excitation bandwidth 5 nm and fluorescence bandwidth 1 nm. The emission intensity compared with each sample is an intensity at a wavelength of 523 nm which is the maximum intensity of the emission spectrum.
表１及び表２から明らかなように、比較例１では、シリカ粉末のＢＥＴ比表面積が５０ｍ2／ｇと小さく、また嵩密度が５８ｇ／Ｌと低かったため、焼成時に他の粉末との反応性が悪く、均一な固相反応が遂行せず、得られたケイ酸塩蛍光体の不純物残渣を示すＢ／Ａが６．６％と高く、発光強度は８０と低かった。 As apparent from Tables 1 and 2, in Comparative Example 1, since the BET specific surface area of the silica powder was as small as 50 m 2 / g and the bulk density was as low as 58 g / L, the reactivity with other powders at the time of calcination was The B / A indicating the impurity residue of the obtained silicate phosphor was as high as 6.6%, and the emission intensity was as low as 80.
比較例２では、シリカ粉末の嵩密度が５５ｇ／Ｌと低く、他の粉末と均一に混ざり合わず、焼成時に他の粉末との反応性が悪く、均一な固相反応が遂行せず、得られたケイ酸塩蛍光体の不純物残渣を示すＢ／Ａが５．１％と高く、発光強度は２３０と低かった。 In Comparative Example 2, the bulk density of the silica powder is as low as 55 g / L, and it does not mix uniformly with other powders, the reactivity with other powders is poor at the time of firing, and uniform solid phase reaction is not performed. The B / A indicating the impurity residue of the silicate phosphor was as high as 5.1%, and the emission intensity was as low as 230.
比較例３では、シリカ粉末が他の実施例、比較例の乾式シリカ粉末と異なり、ゾルゲル法で生成された湿式シリカ粉末であったため、Ｎａの含有量が２１ｐｐｍと多く、水分含有量は３．０％と多かった。このため、得られたケイ酸塩蛍光体の不純物残渣を示すＢ／Ａが１２％と高く、発光強度は６０と低かった。 In Comparative Example 3, unlike the dry silica powders of the other examples and comparative examples, the silica powder is a wet silica powder produced by the sol-gel method, so the content of Na is as high as 21 ppm, and the water content is 3.3. There were as many as 0%. For this reason, B / A which shows the impurity residue of the obtained silicate fluorescent substance was as high as 12%, and luminous intensity was as low as 60.
比較例４では、シリカ粉末が他の実施例、比較例の乾式シリカ粉末と異なり、溶融式シリカ粉末であったため、ＢＥＴ比表面積が３．４ｍ2／ｇと極端に小さく、嵩密度が９００ｇ／Ｌと極端に高かった。このため、得られたケイ酸塩蛍光体の不純物残渣を示すＢ／Ａが１５％と高く、発光強度は４０と低かった。 In Comparative Example 4, unlike the dry silica powders of the other examples and comparative examples, the silica powder is a fused silica powder, so the BET specific surface area is extremely small at 3.4 m 2 / g, and the bulk density is 900 g / g. L was extremely high. For this reason, B / A which shows the impurity residue of the obtained silicate fluorescent substance was as high as 15%, and luminous intensity was as low as 40.
比較例５は、シリカ粉末が乾式シリカ粉末であったが、Ｃｌの含有量が１０１ｐｐｍと多かった。このため、不純物残渣を示すＢ／Ａが１０％が高く、得られたケイ酸塩蛍光体の発光強度は４３０と低かった。 In Comparative Example 5, the silica powder was a dry silica powder, but the content of Cl was as high as 101 ppm. For this reason, B / A which shows an impurity residue was 10% high, and the luminescence intensity of the obtained silicate fluorescent substance was as low as 430.
これに対して、実施例１〜９の乾式シリカ粉末は、各パラメータが第１の観点の範囲内にあったため、得られたケイ酸塩蛍光体の不純物残渣を示すＢ／Ａが１％未満と低く、また発光強度は６３０〜２６６０と高かった。特にシリカ粉末を解砕して分散性と嵩密度を高めるとともに混合粉末をペレット化して焼成した実施例４〜７及び実施例９のケイ酸塩蛍光体の発光強度は１５１０〜２６６０と高かった。 On the other hand, in the dry silica powders of Examples 1 to 9, since each parameter was within the range of the first aspect, B / A indicating the impurity residue of the obtained silicate phosphor was less than 1%. And the emission intensity was as high as 630-2660. In particular, the luminous intensity of the silicate phosphors of Examples 4 to 7 and Example 9 obtained by crushing the silica powder to increase the dispersibility and bulk density and pelletizing the mixed powder and firing were as high as 1510 to 2660.
本発明の乾式シリカ粉末は、例えば青色ＬＥＤを光源として発光する発光ディスプレイや照明等に使用される蛍光体原料として用いられる。 The dry silica powder of the present invention is used, for example, as a phosphor material used for a light emitting display or a light emitting device that emits light using a blue LED as a light source.
Claims (5)
前記ケイ酸塩蛍光体が、Ｘ線回折においてＢａＳｉＯ3の最高回折線強度（Ｂ）と(Ｓｒ,Ｂａ,Ｅｕ)2ＳｉＯ4の最高回折線強度（Ａ）との比（Ｂ／Ａ）が５／１００以下であるケイ酸塩蛍光体の製造方法。 A raw material powder containing Sr raw material powder, Ba raw material powder, Eu raw material powder and dry silica powder according to claim 1 is uniformly mixed with a flux of halogenated Ba powder, and this mixed powder is mixed with a reducing gas and an inert gas. A method of producing a silicate phosphor represented by (Sr, Ba, Eu) 2 SiO 4 by firing under a mixed gas atmosphere of
In the above-mentioned silicate phosphor, the ratio (B / A) of the highest diffraction line intensity (B) of BaSiO 3 to the highest diffraction line intensity (A) of (Sr, Ba, Eu) 2 SiO 4 in X-ray diffraction is The manufacturing method of the silicate fluorescent material which is 5/100 or less.
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