JP2013249215A - Surface treatment method of hydrophilic sol-gel silica particle - Google Patents
Surface treatment method of hydrophilic sol-gel silica particle Download PDFInfo
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 323
- 239000000377 silicon dioxide Substances 0.000 title claims abstract description 96
- 238000004381 surface treatment Methods 0.000 title claims abstract description 86
- 238000000034 method Methods 0.000 title claims description 43
- 239000002245 particle Substances 0.000 title description 31
- 239000000843 powder Substances 0.000 claims abstract description 104
- 238000006243 chemical reaction Methods 0.000 claims abstract description 76
- 230000002209 hydrophobic effect Effects 0.000 claims abstract description 51
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 46
- 239000011261 inert gas Substances 0.000 claims abstract description 34
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 18
- 238000001035 drying Methods 0.000 claims abstract description 15
- 239000000654 additive Substances 0.000 claims description 26
- 239000011164 primary particle Substances 0.000 claims description 25
- 230000000996 additive effect Effects 0.000 claims description 23
- 239000003960 organic solvent Substances 0.000 claims description 9
- 239000007863 gel particle Substances 0.000 claims description 7
- -1 silicon alkoxide Chemical class 0.000 claims description 6
- 239000007859 condensation product Substances 0.000 claims description 5
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- 230000003301 hydrolyzing effect Effects 0.000 claims description 3
- 125000004178 (C1-C4) alkyl group Chemical group 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 abstract description 13
- 230000000052 comparative effect Effects 0.000 description 27
- 238000003756 stirring Methods 0.000 description 24
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 20
- 229910001873 dinitrogen Inorganic materials 0.000 description 14
- 239000002904 solvent Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 5
- 239000010419 fine particle Substances 0.000 description 5
- FFUAGWLWBBFQJT-UHFFFAOYSA-N hexamethyldisilazane Chemical compound C[Si](C)(C)N[Si](C)(C)C FFUAGWLWBBFQJT-UHFFFAOYSA-N 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- 239000011347 resin Substances 0.000 description 5
- 238000003980 solgel method Methods 0.000 description 5
- 239000006185 dispersion Substances 0.000 description 4
- 239000012530 fluid Substances 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 125000006850 spacer group Chemical group 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 241000519995 Stachys sylvatica Species 0.000 description 3
- 238000004220 aggregation Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 description 3
- 125000004432 carbon atom Chemical group C* 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 3
- 125000001183 hydrocarbyl group Chemical group 0.000 description 3
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 150000003961 organosilicon compounds Chemical class 0.000 description 3
- 229910000077 silane Inorganic materials 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 3
- 238000005303 weighing Methods 0.000 description 3
- 230000004580 weight loss Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 238000000944 Soxhlet extraction Methods 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 2
- IJOOHPMOJXWVHK-UHFFFAOYSA-N chlorotrimethylsilane Chemical compound C[Si](C)(C)Cl IJOOHPMOJXWVHK-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000005661 hydrophobic surface Effects 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 2
- UQMOLLPKNHFRAC-UHFFFAOYSA-N tetrabutyl silicate Chemical compound CCCCO[Si](OCCCC)(OCCCC)OCCCC UQMOLLPKNHFRAC-UHFFFAOYSA-N 0.000 description 2
- ZQZCOBSUOFHDEE-UHFFFAOYSA-N tetrapropyl silicate Chemical compound CCCO[Si](OCCC)(OCCC)OCCC ZQZCOBSUOFHDEE-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000003849 aromatic solvent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- KOPOQZFJUQMUML-UHFFFAOYSA-N chlorosilane Chemical class Cl[SiH3] KOPOQZFJUQMUML-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- ZMAPKOCENOWQRE-UHFFFAOYSA-N diethoxy(diethyl)silane Chemical compound CCO[Si](CC)(CC)OCC ZMAPKOCENOWQRE-UHFFFAOYSA-N 0.000 description 1
- JJQZDUKDJDQPMQ-UHFFFAOYSA-N dimethoxy(dimethyl)silane Chemical compound CO[Si](C)(C)OC JJQZDUKDJDQPMQ-UHFFFAOYSA-N 0.000 description 1
- LIKFHECYJZWXFJ-UHFFFAOYSA-N dimethyldichlorosilane Chemical compound C[Si](C)(Cl)Cl LIKFHECYJZWXFJ-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- POPACFLNWGUDSR-UHFFFAOYSA-N methoxy(trimethyl)silane Chemical compound CO[Si](C)(C)C POPACFLNWGUDSR-UHFFFAOYSA-N 0.000 description 1
- ARYZCSRUUPFYMY-UHFFFAOYSA-N methoxysilane Chemical compound CO[SiH3] ARYZCSRUUPFYMY-UHFFFAOYSA-N 0.000 description 1
- BFXIKLCIZHOAAZ-UHFFFAOYSA-N methyltrimethoxysilane Chemical compound CO[Si](C)(OC)OC BFXIKLCIZHOAAZ-UHFFFAOYSA-N 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 108091008695 photoreceptors Proteins 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- ADLSSRLDGACTEX-UHFFFAOYSA-N tetraphenyl silicate Chemical compound C=1C=CC=CC=1O[Si](OC=1C=CC=CC=1)(OC=1C=CC=CC=1)OC1=CC=CC=C1 ADLSSRLDGACTEX-UHFFFAOYSA-N 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- 239000005051 trimethylchlorosilane Substances 0.000 description 1
- 239000002966 varnish Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
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- Silicon Compounds (AREA)
- Developing Agents For Electrophotography (AREA)
Abstract
Description
本発明は、親水性ゾルゲルシリカシリカ粒子を乾式法によって疎水化して疎水性ゾルゲルシリカ粉末を得るための表面処理方法に関する。本明細書で「乾式法による粒子の表面処理」とは、処理粒子を液体中に浸漬又は懸濁させずに行う表面処理のことをいい、例えば粒子に処理用化合物の蒸気を接触させる方法、粒子を流動状態にし処理用化合物の液体又は溶液を噴霧又は滴下する方法などが挙げられる。 The present invention relates to a surface treatment method for obtaining hydrophobic sol-gel silica powder by hydrophobizing hydrophilic sol-gel silica silica particles by a dry method. In the present specification, the “surface treatment of particles by a dry method” refers to a surface treatment performed without immersing or suspending treated particles in a liquid, for example, a method of contacting particles with a vapor of a treatment compound, Examples thereof include a method in which particles are made into a fluid state and a liquid or solution of a treatment compound is sprayed or dropped.
微細なシリカ粉末は、その表面を改質・処理して帯電性や疎水性を改善することにより、複写機、プリンター、ファクシミリ、製版システムなどの静電荷現像用トナーに添加されて広く用いられている。このトナー外添剤としての微細なシリカ粉末は、トナーの、流動性の改善、帯電性の制御、長期保存安定性、クリーニング特性の制御、現像剤劣化挙動の制御などを目的としている。 Fine silica powder is widely used by adding to electrostatic charge developing toners for copiers, printers, facsimiles, plate making systems, etc. by modifying and treating the surface to improve chargeability and hydrophobicity. Yes. The fine silica powder as an external toner additive is intended to improve toner flowability, control charging properties, long-term storage stability, control cleaning properties, control developer deterioration behavior, and the like.
従来、このような用途に用いられるシリカ粉末はトナーに流動性を付与する流動性改善剤として、乾式法で製造された微細なシリカ粒子を疎水化したシリカ粒子が一般的に使用されている。この乾式法で製造されたシリカ粒子に所定の有機物による表面処理をするときには、シリカ粒子の高分散性を維持させるためにその表面処理も乾式法で実施することが一般的である(例えば、特許文献1参照)。しかしながら、特許文献1の方法で製造されたシリカ粉末はその平均一次粒子径が7〜30nmの微細な粉末しか得られない。一方、湿式法で製造されたシリカ粒子を疎水化したシリカ粉末もトナー外添剤として使用されており、その中でも特にゾルゲル法により製造されたいわゆるゾルゲルシリカ粒子を疎水化した疎水性ゾルゲルシリカ粉末は、上記特許文献1に示されたシリカ粉末と異なり、一次粒子径100nm程度の大粒子径品を製造可能であり、かつ、粒子径に均一性があり、更に単分散に、より近い形での凝集粒子状態を維持している。これらの利点から、ゾルゲルシリカ粉末は特にトナー外添剤として用いられ、その大粒子径の特徴を活かして小粒子径のトナー外添剤がトナー内部に埋め込まれてしまうことを防止するためのスペーサー効果を発現するための材料として広く使用されている。 Conventionally, the silica powder used for such a use is generally used as a fluidity improver for imparting fluidity to a toner, and silica particles obtained by hydrophobizing fine silica particles produced by a dry method are generally used. When silica particles produced by this dry method are subjected to a surface treatment with a predetermined organic substance, the surface treatment is generally carried out by a dry method in order to maintain high dispersibility of the silica particles (for example, patents). Reference 1). However, the silica powder produced by the method of Patent Document 1 can only obtain a fine powder having an average primary particle size of 7 to 30 nm. On the other hand, silica powder produced by hydrophobizing silica particles produced by a wet method is also used as a toner external additive. Among them, a hydrophobic sol-gel silica powder produced by hydrophobizing so-called sol-gel silica particles produced by a sol-gel method is particularly used. Unlike the silica powder disclosed in Patent Document 1 above, it is possible to produce a large particle size product having a primary particle size of about 100 nm, and the particle size is uniform, and further in a form closer to monodispersion. The aggregated particle state is maintained. Because of these advantages, the sol-gel silica powder is used as a toner external additive, and a spacer for preventing the toner external additive having a small particle diameter from being embedded in the toner by taking advantage of the characteristics of the large particle diameter. It is widely used as a material for producing an effect.
一般に、トナーは複写機等の内部で撹拌され、キャリアなどとの摩擦によって帯電する。そして、その高度に制御された帯電性によって現像機能を発現する。しかし、トナーが長時間装置内で撹拌され続けると、撹拌に起因する強い摩擦力がストレスになり、トナーの劣化が進行する。例えば、トナー外添剤はトナー表面に埋没することにより、トナー表面と外部環境との接点としての目的の機能を失う。
しかし、上述のようにトナーへの機械的負荷は近年増大し、かつ、トナーの結着性樹脂の軟化によりトナー母体の硬度は低くなっている。この結果、上記のようなトナー外添剤のトナーへの埋没防止の対策の重要性は益々高まっている。
Generally, toner is agitated inside a copying machine or the like, and is charged by friction with a carrier or the like. The developing function is manifested by the highly controlled chargeability. However, when the toner is continuously stirred in the apparatus for a long time, the strong frictional force resulting from the stirring becomes a stress and the deterioration of the toner proceeds. For example, the toner external additive is buried in the toner surface, thereby losing the intended function as a contact point between the toner surface and the external environment.
However, as described above, the mechanical load on the toner has increased in recent years, and the hardness of the toner base has decreased due to the softening of the binder resin of the toner. As a result, the importance of measures for preventing the toner external additives from being buried in the toner is increasing.
このようなトナー外添剤の埋没は、トナー外添剤の粉末の粒子の一次粒子径が20nm未満の場合において特に顕著に見られる。これを防止する目的で、一次粒子が100nm以上のトナー外添剤の粉末の粒子がスペーサーとして補助的に使用されることがある。特に、シリコンアルコキシドを原料としてゾルゲル法により製造される湿式法による親水性ゾルゲルシリカ粒子は均一な粒子径が得られると共に球状で流動性付与効果が高いなどの理由から好んで用いられている。 Such embedding of the toner additive is particularly noticeable when the primary particle diameter of the toner additive powder particles is less than 20 nm. For the purpose of preventing this, particles of toner external additive powder having primary particles of 100 nm or more may be used as a supplementary spacer. In particular, hydrophilic sol-gel silica particles produced by a sol-gel method using silicon alkoxide as a raw material are preferably used because they have a uniform particle size and are spherical and have a high fluidity-imparting effect.
また、近年電子写真の高画質化によりトナー粒子の小粒子径化が進み、それに加えて印刷速度の高速化、電子写真のカラー化により、トナーへの機械的負荷は益々大きくなっている。そのため、トナー性能の経時耐久性を担保するためにトナーの劣化挙動の制御が特に重要度を増している。しかし、一方では印刷待機時間の短縮化や省エネルギーを目的として、トナーに使用される結着性樹脂、即ちトナー母体樹脂には低温定着性が求められるため、トナー母体樹脂の硬度は軟化の傾向にある。 In recent years, toner particles have become smaller in size due to higher image quality of electrophotography, and in addition to this, the mechanical load on the toner has been increasing due to higher printing speed and colorization of electrophotography. Therefore, control of the deterioration behavior of the toner is particularly important in order to ensure the durability of the toner performance over time. However, on the other hand, for the purpose of shortening the printing standby time and saving energy, the binder resin used for the toner, that is, the toner base resin, is required to have a low temperature fixability, so the hardness of the toner base resin tends to be softened. is there.
このゾルゲル法により製造されるゾルゲルシリカ粒子を疎水化する方法として、ヒドロカルビルシラン若しくはその部分加水分解縮合生成物又はそれらの組み合わせを加水分解及び縮合することによって得られた親水性球状ゾルゲルシリカ微粒子を疎水化処理して得られた疎水性球状ゾルゲルシリカ微粒子を加熱処理して熱処理球状ゾルゲルシリカ微粒子を得る工程と、この熱処理球状ゾルゲルシリカ微粒子を疎水化処理する工程とを含む平均一次粒子径が0.01〜5μmの高疎水性球状ゾルゲルシリカ微粒子の製造方法が開示されている(例えば特許文献2参照)。
この特許文献2に示される親水性球状ゾルゲル微粒子の疎水化処理は湿式法で行われる。この方法では、例えば、親水性ゾルゲルシリカ粒子を含む水性分散液、炭化水素系溶媒、芳香族系溶媒、ケトン系溶媒分散液等の有機溶媒分散液、又は水−親水性有機溶媒の混合溶媒分散液に、下記一般式:
R3 3SiNHSiR3 3
(式中、R3は同一または異なり、置換または非置換の炭素原子数1〜20の1価炭化水素基である)で表されるシラザン化合物、または下記一般式:
R3 3SiX
(式中、R3は上記と同じであり、XはOH基又は加水分解性基である)で表される1官能性シラン化合物、或いはこれらの組み合わせを添加し、上記親水性ゾルゲルシリカ粒子表面に残存する反応性基をトリオルガノシリル化して疎水化している。
As a method for hydrophobizing sol-gel silica particles produced by this sol-gel method, hydrophilic spherical sol-gel silica particles obtained by hydrolyzing and condensing hydrocarbylsilane or its partial hydrolysis-condensation product or a combination thereof are made hydrophobic. The average primary particle size including the step of heat-treating the spherical spherical sol-gel silica fine particles obtained by heat treatment to obtain heat-treated spherical sol-gel silica fine particles and the step of hydrophobizing the heat-treated spherical sol-gel silica fine particles is 0. A method for producing 01 to 5 μm highly hydrophobic spherical sol-gel silica fine particles has been disclosed (see, for example, Patent Document 2).
The hydrophobizing treatment of the hydrophilic spherical sol-gel fine particles shown in Patent Document 2 is performed by a wet method. In this method, for example, an aqueous dispersion containing hydrophilic sol-gel silica particles, a hydrocarbon solvent, an aromatic solvent, an organic solvent dispersion such as a ketone solvent dispersion, or a mixed solvent dispersion of a water-hydrophilic organic solvent. In the liquid, the following general formula:
R 3 3 SiNHSiR 3 3
Wherein R 3 is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, or the following general formula:
R 3 3 SiX
(Wherein R 3 is the same as above, and X is an OH group or a hydrolyzable group), or a combination thereof, and the hydrophilic sol-gel silica particle surface The reactive groups remaining in the substrate are hydrophobized by triorganosilylation.
トナー外添剤に特許文献2に示されるゾルゲル法で製造されたシリカ粒子を疎水化したシリカ粉末を適用する場合には、その製造方法に起因して、ゾルゲルシリカ粒子が水分又は有機溶媒を含み、シリカ粒子同士が非常に凝集し易くかつかさ密度が高いため、ゾルゲルシリカ粒子に対して乾式法で表面処理を試みると、ゾルゲルシリカシリカ粒子が十分に分散できず、一次粒子と共に数千個が固まりをなしてシリカ粒子の凝集体となる場合が多く見受けられ、均一な表面処理を行うことが困難であった。 When the silica powder obtained by hydrophobizing silica particles produced by the sol-gel method disclosed in Patent Document 2 is applied to the toner external additive, the sol-gel silica particles contain water or an organic solvent due to the production method. The silica particles are very easily aggregated and have a high bulk density. Therefore, when a surface treatment is attempted on the sol-gel silica particles by a dry method, the sol-gel silica silica particles cannot be sufficiently dispersed, and thousands of particles are formed together with the primary particles. In many cases, agglomerates of silica particles are formed and it is difficult to perform uniform surface treatment.
また、トナー外添剤に特許文献2に示される湿式法のゾルゲル法で製造されたゾルゲルシリカ粒子を疎水化したシリカ粉末を適用する場合には、疎水化剤をゾルゲルシリカ粒子と共に溶媒中に分散させ、シリカ粒子に表面処理するために、一般的に濾過、乾燥等の工程を必要として長い工程が必要となる。その上、一般的に疎水化剤は水分によって分解するものもあるため、十分な疎水性が得られにくいという不具合がある。この不具合はシリカ粒子の凝集体が十分にトナー外添剤としての役割を果たさなくなるだけでなく、その凝集体が大きいことに起因して他の弊害が発生する原因となる。更に表面改質をする際に、シリカ粒子の凝集体内部まで疎水化剤が十分に反応できないために、未反応の処理斑が発生し疎水化しにくいという不具合も起きている。 In addition, when applying silica powder obtained by hydrophobizing sol-gel silica particles produced by the wet sol-gel method disclosed in Patent Document 2 to the toner external additive, the hydrophobizing agent is dispersed in the solvent together with the sol-gel silica particles. In order to surface-treat the silica particles, generally, a long process is required because processes such as filtration and drying are required. In addition, since some hydrophobizing agents are generally decomposed by moisture, there is a problem that it is difficult to obtain sufficient hydrophobicity. This defect not only prevents the aggregate of silica particles from sufficiently serving as an external toner additive, but also causes other adverse effects due to the large aggregate. Further, when the surface is modified, since the hydrophobizing agent cannot sufficiently react to the inside of the aggregate of silica particles, there is a problem that unreacted processing spots are generated and it is difficult to hydrophobize.
上記の理由により、現在まで、湿式法により製造された親水性ゾルゲルシリカ粒子を乾式法で疎水化するための有効な表面処理方法は未だ見出されていなかった。 For the above reasons, an effective surface treatment method for hydrophobizing hydrophilic sol-gel silica particles produced by a wet method by a dry method has not been found so far.
本発明者らは、上記問題を解決するべく鋭意検討した結果、特定範囲のかさ密度、特定範囲のガス流量、撹拌条件により、乾式法で親水性ゾルゲルシリカ粒子を疎水化するための表面処理を行った場合に、高い疎水性と、低い乾燥減量を有し、適度の炭素分量を含んだ疎水性ゾルゲルシリカ粉末を得る製造方法を見出すに至った。 As a result of intensive studies to solve the above problems, the present inventors have performed a surface treatment for hydrophobizing hydrophilic sol-gel silica particles by a dry method according to a specific range of bulk density, a specific range of gas flow rate, and stirring conditions. When carried out, the inventors have found a production method for obtaining a hydrophobic sol-gel silica powder having high hydrophobicity, low loss on drying and containing an appropriate carbon content.
本発明は、従来より湿式法で製造されたゾルゲルシリカ粒子の表面処理方法の問題点を解決するために、高い疎水性と低い乾燥減量を有し、適度の炭素分量を含んだ疎水性ゾルゲルシリカ粉末を得る親水性ゾルゲルシリカ粒子の表面処理方法を提供することを目的とする。 In order to solve the problems of the surface treatment method of sol-gel silica particles conventionally produced by a wet method, the present invention is a hydrophobic sol-gel silica having high hydrophobicity and low loss on drying and containing an appropriate carbon content. An object of the present invention is to provide a surface treatment method for hydrophilic sol-gel silica particles to obtain a powder.
本発明の第1の観点は、下記の一般式(1)に示されるケイ素アルコキシド若しくはその部分加水分解縮合生成物又はそれらの組み合わせを加水分解及び縮合することによって得られた親水性ゾルゲルシリカ粒子を疎水化剤により表面処理する方法において、前記表面処理は前記親水性ゾルゲルシリカ粒子を反応容器に入れた状態で不活性ガス及び前記疎水化剤を前記反応容器内に供給して前記親水性ゾルゲルシリカ粒子を流動させて行う乾式表面処理であって、前記反応容器内に供給する前記不活性ガスの前記反応容器の横断面積当りの線速度を1〜12m/sの範囲に設定し、前記表面処理時の前記親水性ゾルゲル粒子のかさ密度を前記反応容器内に静置したときの前記親水性ゾルゲルシリカ粒子のかさ密度の0.6〜0.9倍の範囲に設定するとともに、前記反応容器内で表面処理時の親水性ゾルゲルシリカ粒子のかさ密度を150〜300g/Lの範囲に設定することにより表面が疎水化された疎水性ゾルゲルシリカ粉末を得ることを特徴とする親水性ゾルゲルシリカ粒子の表面処理方法である。
Si(OR1)4 (1)
(但し、R1は同一又は異なる炭素数1〜4のアルキル基である。)
A first aspect of the present invention is to provide hydrophilic sol-gel silica particles obtained by hydrolyzing and condensing a silicon alkoxide represented by the following general formula (1) or a partial hydrolysis-condensation product thereof or a combination thereof. In the method of surface treatment with a hydrophobizing agent, the surface treatment is performed by supplying an inert gas and the hydrophobizing agent into the reaction vessel in a state where the hydrophilic sol-gel silica particles are placed in the reaction vessel. A dry surface treatment performed by flowing particles, wherein a linear velocity per cross-sectional area of the reaction vessel of the inert gas supplied into the reaction vessel is set in a range of 1 to 12 m / s, and the surface treatment The bulk density of the hydrophilic sol-gel particles at the time is in the range of 0.6 to 0.9 times the bulk density of the hydrophilic sol-gel silica particles when left in the reaction vessel And a hydrophobic sol-gel silica powder having a hydrophobic surface is obtained by setting the bulk density of the hydrophilic sol-gel silica particles during the surface treatment in the reaction vessel in the range of 150 to 300 g / L. This is a surface treatment method for hydrophilic sol-gel silica particles.
Si (OR 1 ) 4 (1)
(However, R1 is the same or different C1-C4 alkyl group.)
本発明の第2の観点は、第1の観点の発明の表面処理方法であって、前記表面処理前の親水性ゾルゲルシリカ粒子の平均一次粒子径が50〜300nmの範囲にある表面処理方法である。 A second aspect of the present invention is the surface treatment method of the first aspect of the invention, wherein the hydrophilic sol-gel silica particles before the surface treatment have an average primary particle diameter in the range of 50 to 300 nm. is there.
本発明の第3の観点は、第1又は2の観点の発明により表面処理された疎水性ゾルゲルシリカ粉末であって、乾燥減量が0.8質量%以下であり、疎水化率が70〜100%の範囲にあり、かつ有機溶剤抽出分の含有炭素分が単位面積当り0.001〜0.03質量%にある疎水性ゾルゲルシリカ粉末である。 A third aspect of the present invention is a hydrophobic sol-gel silica powder surface-treated according to the invention of the first or second aspect, having a loss on drying of 0.8% by mass or less, and a hydrophobization rate of 70 to 100 %, And the content of carbon contained in the organic solvent extract is 0.001 to 0.03% by mass per unit area.
本発明の第4の観点は、本発明の第3の観点の疎水性ゾルゲルシリカ粉末から得られた静電荷像現像用トナー外添剤である。 A fourth aspect of the present invention is a toner external additive for developing electrostatic images obtained from the hydrophobic sol-gel silica powder of the third aspect of the present invention.
本発明の第1の観点によれば、親水性ゾルゲルシリカ粒子を疎水化剤を用いて表面処理する際に前記反応容器内に供給する不活性ガスの反応容器の横断面積当りの線速度を1〜12m/sの範囲に設定し、前記表面処理時の前記親水性ゾルゲル粒子のかさ密度を前記反応容器内に静置したときの前記親水性ゾルゲルシリカ粒子のかさ密度の0.6〜0.9倍の範囲に設定するとともに、前記反応容器内で表面処理時の親水性ゾルゲルシリカ粒子のかさ密度を150〜300g/Lの範囲に設定することにより、反応容器内でシリカ粒子を十分に分散させてシリカ粒子の凝集体を作ることなくシリカ粒子を疎水化剤と十分に反応することができ、これにより高い疎水性と低い乾燥減量を有し、適度の炭素分量を含んだ疎水性ゾルゲルシリカ粉末が得られる。 According to the first aspect of the present invention, when the hydrophilic sol-gel silica particles are surface-treated with a hydrophobizing agent, the linear velocity per cross-sectional area of the reaction vessel of the inert gas supplied into the reaction vessel is set to 1. The bulk density of the hydrophilic sol-gel particles at the time of the surface treatment is set in the range of ˜12 m / s, and the bulk density of the hydrophilic sol-gel silica particles when left in the reaction vessel is 0.6 to 0. By setting the range of 9 times and setting the bulk density of the hydrophilic sol-gel silica particles during the surface treatment in the reaction vessel in the range of 150 to 300 g / L, the silica particles are sufficiently dispersed in the reaction vessel. Hydrophobic sol-gel silica with high hydrophobicity, low loss on drying, and moderate carbon content, which can react well with hydrophobizing agents without making silica particle aggregates Powder Obtained.
本発明の第2の観点によれば、前記表面処理前の親水性ゾルゲルシリカ粒子の平均一次粒子径が50〜300nmの範囲にあるため、その大粒径の特徴を活かしてより小粒子径のトナー外添剤がトナー内部に埋め込まれてしまうことを防止するためのスペーサー効果を発現することができる。 According to the second aspect of the present invention, since the average primary particle diameter of the hydrophilic sol-gel silica particles before the surface treatment is in the range of 50 to 300 nm, the smaller particle diameter is utilized by taking advantage of the characteristics of the large particle diameter. A spacer effect for preventing the toner external additive from being embedded in the toner can be exhibited.
本発明の第3の観点によれば、乾燥減量が上記範囲にあるため、トナー外添剤として用いたときに、表面処理前の水分又は表面処理による有機溶媒の揮発成分の発生を防止して、トナーに与えられる電荷を安定させることができる。また疎水化率が上記の範囲にあるため、同電荷の十分な環境安定性が得られると共にシリカ粒子を円滑に流動させることができ、そして有機溶剤抽出分の含有炭素分(カーボン量)が単位面積当りの上記の範囲にあるため、有機物による疎水化のための表面処理が十分に行われ、かつトナーの帯電安定性、トナーの分散性が良好になり、更にトナーの凝集を防止できる。 According to the third aspect of the present invention, since the loss on drying is in the above range, when it is used as an external toner additive, it prevents moisture before the surface treatment or generation of volatile components of the organic solvent due to the surface treatment. The charge applied to the toner can be stabilized. In addition, since the hydrophobization rate is in the above range, sufficient environmental stability with the same charge can be obtained and silica particles can flow smoothly, and the carbon content (carbon amount) contained in the organic solvent extract can be measured in units. Since it is in the above range per area, surface treatment for hydrophobizing with organic substances is sufficiently performed, toner charging stability and toner dispersibility are improved, and toner aggregation can be prevented.
本発明の第4の観点は、本発明の第3の観点の疎水性ゾルゲルシリカ粉末から得られた静電荷像現像用トナー外添剤であるため、トナーの帯電安定性やトナーの分散性が良好にな更にトナーの凝集等を防止できる。 The fourth aspect of the present invention is a toner external additive for developing an electrostatic charge image obtained from the hydrophobic sol-gel silica powder of the third aspect of the present invention, so that the charging stability of the toner and the dispersibility of the toner are improved. It is possible to prevent further toner aggregation and the like.
本発明は、乾式表面処理によって、反応容器内で所定の粒子径の親水性ゾルゲルシリカ粒子に疎水化剤を均一かつ十分に付与して疎水性ゾルゲルシリカ粉末を得る表面処理方法である。
本発明の乾式表面処理は、疎水化すべき親水性ゾルゲルシリカ粒子を液体中に浸漬ないし懸濁させずに行う表面処理であって、親水性ゾルゲルシリカ粒子を流動下又は撹拌下で疎水化剤を噴霧する表面処理、又は親水性ゾルゲルシリカ粒子を流動下又は撹拌下を疎水化剤の蒸気を導入する。このとき疎水化剤を加えた後に必要に応じて加熱してもよい。疎水化剤を1種のみならず2種以上供給してもよい。2種以上の疎水化剤を供給する場合には2種以上の疎水化剤を同時に反応させても良いし逐次的に反応させても良い。
The present invention is a surface treatment method for obtaining a hydrophobic sol-gel silica powder by uniformly and sufficiently imparting a hydrophobizing agent to hydrophilic sol-gel silica particles having a predetermined particle size in a reaction vessel by dry surface treatment.
The dry surface treatment of the present invention is a surface treatment performed without immersing or suspending the hydrophilic sol-gel silica particles to be hydrophobized in a liquid, and the hydrophilic sol-gel silica particles are treated with a hydrophobizing agent under flow or stirring. The surface treatment to be sprayed or the hydrophobizing agent vapor is introduced under flow or stirring of the hydrophilic sol-gel silica particles. At this time, after adding a hydrophobizing agent, it may be heated as necessary. You may supply not only 1 type but 2 or more types of hydrophobizing agents. When two or more types of hydrophobizing agents are supplied, two or more types of hydrophobizing agents may be reacted simultaneously or sequentially.
上記の乾式表面処理を均一かつ良好に行うには、乾式表面処理用の反応容器の形状は、鉛直に設置された円筒状又は略球状のものとすることが好ましく、かつ、親水性ゾルゲルシリカ粒子を流動させる手段が必要である。また適宜反応促進のための加温手段を備えることが好ましい。本発明の第1の実施形態として図1に示すような円筒状の反応容器を用いる乾式表面処理方法を、更に、本発明の第2の実施形態として図2に示すような球状の反応容器を用いる乾式表面処理方法を以下説明する。 In order to perform the above dry surface treatment uniformly and satisfactorily, the shape of the reaction vessel for dry surface treatment is preferably a cylindrical or substantially spherical shape installed vertically, and hydrophilic sol-gel silica particles It is necessary to have a means for fluidizing. Moreover, it is preferable to equip the heating means for reaction promotion suitably. A dry surface treatment method using a cylindrical reaction vessel as shown in FIG. 1 as a first embodiment of the present invention, and a spherical reaction vessel as shown in FIG. 2 as a second embodiment of the present invention. The dry surface treatment method used will be described below.
<第1の実施形態>
先ず疎水化すべき親水性ゾルゲルシリカ粒子は、下記の一般式(1)に示されるケイ素アルコキシド若しくはその部分加水分解縮合生成物又はそれらの組み合わせを加水分解及び縮合することによって得られる。
Si(OR1)4 (1)
(但し、R1は同一又は異なる炭素数1〜4のアルキル基である。)
一般式(1)中、R1は、炭素原子数1〜4であるが特に好ましくは1〜2の1価炭化水素基である。R1で表される1価炭化水素基としては、例えば、メチル基、エチル基、プロピル基、ブチル基、フェニル基等、好ましくは、メチル基、エチル基、プロピル基、ブチル基、特に好ましくは、メチル基、エチル基が挙げられる。また一般式(1)で表される4官能性シラン化合物としては、例えば、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシラン、テトラブトキシシラン等のテトラアルコキシシラン、テトラフェノキシシラン等、好ましくは、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシラン、テトラブトキシシラン、特に好ましくは、テトラメトキシシラン、テトラエトキシシランが挙げられる。また、上記一般式(1)で表される4官能性シラン化合物の部分加水分解縮合生成物としては、例えば、メチルシリケート、エチルシリケート等が挙げられる。
<First Embodiment>
First, the hydrophilic sol-gel silica particles to be hydrophobized are obtained by hydrolysis and condensation of a silicon alkoxide represented by the following general formula (1) or a partial hydrolysis-condensation product thereof or a combination thereof.
Si (OR 1 ) 4 (1)
(Wherein, R 1 is the same or different alkyl group of 1 to 4 carbon atoms.)
In the general formula (1), R1 is a monovalent hydrocarbon group having 1 to 4 carbon atoms, particularly preferably 1 to 2. Examples of the monovalent hydrocarbon group represented by R1 include a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group, preferably a methyl group, an ethyl group, a propyl group, and a butyl group, and particularly preferably Examples thereof include a methyl group and an ethyl group. Examples of the tetrafunctional silane compound represented by the general formula (1) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, tetraphenoxysilane, and the like. Methoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, particularly preferably tetramethoxysilane and tetraethoxysilane. Examples of the partial hydrolysis-condensation product of the tetrafunctional silane compound represented by the general formula (1) include methyl silicate and ethyl silicate.
そして、上記方法で得られた親水性ゾルゲルシリカ粒子の中で平均一次粒子径が50〜300nmの範囲にある親水性ゾルゲルシリカ粒子が好ましい。平均一次粒子径が、50nm未満の場合、表面処理した疎水性ゾルゲルシリカ粉末の粒子が小さくなるため、実質上スペーサー効果が小さくなり又はトナーに埋没し易くなるという不具合がある、一方、300nmを越える場合、トナー表面からの脱離が生じやすく、その結果十分な画像特性が出ない又は画像に白抜けが出やすい等の画像特性に大きな問題を発生させる場合が多くなるという不具合がある。結果として上記平均一次粒子径の範囲から外れるとトナーの外添剤として適当でなくなる。更に平均一次粒子径は80〜180nmであることが好ましい。上記の不具合を更に低減できるからである。 Among the hydrophilic sol-gel silica particles obtained by the above method, hydrophilic sol-gel silica particles having an average primary particle diameter in the range of 50 to 300 nm are preferable. When the average primary particle size is less than 50 nm, the surface-treated hydrophobic sol-gel silica powder particles become smaller, so that there is a problem that the spacer effect is substantially reduced or the toner is easily embedded in the toner, whereas it exceeds 300 nm. In such a case, there is a problem in that separation from the toner surface is likely to occur, and as a result, a large problem is often caused in image characteristics such as insufficient image characteristics or white spots in an image. As a result, if the average primary particle diameter is out of the range, the toner is not suitable as an external additive for the toner. Further, the average primary particle diameter is preferably 80 to 180 nm. This is because the above problems can be further reduced.
次に、図1に示される流動床の反応容器1によって、準備された親水性ゾルゲルシリカ粒子14を疎水化するための表面処理を行う。
図1に示すように、流動床の反応容器1は、両端が閉止されかつ鉛直方向に延びる円筒状の筒本体2と、この筒本体2の側面中央に接続され親水性ゾルゲルシリカ粒子14を筒本体2に導入する原料導入管3と、筒本体2内の下端近傍に設けられ親水性ゾルゲルシリカ粒子14を受ける整流板4と、筒本体2の底壁2aに接続され疎水化剤及び不活性ガスを導入管5から筒本体2に導入する導入管5とを備えている。
Next, surface treatment for hydrophobizing the prepared hydrophilic sol-gel silica particles 14 is performed by the reaction vessel 1 of the fluidized bed shown in FIG.
As shown in FIG. 1, a fluidized bed reaction vessel 1 includes a cylindrical tube body 2 having both ends closed and extending in the vertical direction, and hydrophilic sol-gel silica particles 14 connected to the center of the side surface of the tube body 2. A raw material introduction tube 3 to be introduced into the main body 2, a rectifying plate 4 provided near the lower end in the cylindrical main body 2 and receiving the hydrophilic sol-gel silica particles 14, a hydrophobizing agent and an inert gas connected to the bottom wall 2 a of the cylindrical main body 2 And an introduction pipe 5 for introducing gas from the introduction pipe 5 into the cylinder main body 2.
疎水化剤は、有機ケイ素系化合物が用いられる。この有機ケイ素径化合物に特に制限は無いが、一般的な例としてヘキサメチルジシラザンのようなアルキルシラザン系化合物、ジメチルジメトキシシラン、ジエチルジエトキシシラン、トリメチルメトキシシラン、メチルトリメトキシシラン、ブチルトリメトキシシランのようなアルキルアルコキシシラン系化合物、ジメチルジクロロシラン、トリメチルクロロシランのようなクロロシラン系化合物、あるいはシリコーンオイル、シリコーンワニスなどを用いることができる。これらの疎水化剤は1種を単独で用いても良く、2種以上を混合して用いても良い。
不活性ガスは、一般的な例としてヘリウム、窒素、アルゴン等が挙げられる。工業的に使用する場合、コスト面から窒素ガスが好ましい。
As the hydrophobizing agent, an organosilicon compound is used. There are no particular restrictions on the organosilicon diameter compound, but general examples include alkylsilazane compounds such as hexamethyldisilazane, dimethyldimethoxysilane, diethyldiethoxysilane, trimethylmethoxysilane, methyltrimethoxysilane, and butyltrimethoxy. Alkyl alkoxysilane compounds such as silane, chlorosilane compounds such as dimethyldichlorosilane and trimethylchlorosilane, silicone oil, silicone varnish, and the like can be used. These hydrophobizing agents may be used alone or in a combination of two or more.
Examples of the inert gas include helium, nitrogen, and argon as general examples. When industrially used, nitrogen gas is preferred from the viewpoint of cost.
整流板4は、親水性ゾルゲルシリカ粒子14の粒子径より細かい多数の孔を有する多孔質又は網状に形成され、不活性ガスを鉛直上方向に整流する。また筒本体2の側面のうち整流板4より僅かに高い位置には下側取出し管6が接続され、筒本体2の側面のうち高さが原料導入管3及び下側取出し管6間に位置するように上側取出し管7が接続される。 The rectifying plate 4 is formed in a porous or net-like shape having many pores smaller than the particle diameter of the hydrophilic sol-gel silica particles 14 and rectifies the inert gas vertically upward. Further, a lower take-out pipe 6 is connected to a position slightly higher than the rectifying plate 4 on the side surface of the cylinder main body 2, and a height of the side face of the cylinder main body 2 is located between the raw material introduction pipe 3 and the lower take-out pipe 6. Thus, the upper take-out pipe 7 is connected.
下側取出し管6にはこの管を開閉する手動バルブ8が設けられ、上側取出し管7にはこの管を通る疎水性ゾルゲルシリカ粉末の流量を調整する流量調整バルブ9が設けられる。また下側取出し管6及び上側取出し管7は合流して集合取出し管10となる。更に筒本体2の上部には親水性ゾルゲルシリカ粒子14が排ガスとともに排出されるのを防止するためのバグフィルタ11が設けられ、筒本体2の上壁2bには排ガスを排出するための排気管12が接続される。手動バルブ8及び流量調整バルブ9を閉じた状態で原料導入管3から筒本体2に所定量かつ平均一次粒子径50〜300nmの範囲にある親水性ゾルゲルシリカ粒子14を供給し、導入管5から筒本体2に疎水化剤及び不活性ガスを導入する。 The lower take-out pipe 6 is provided with a manual valve 8 for opening and closing the pipe, and the upper take-out pipe 7 is provided with a flow rate adjusting valve 9 for adjusting the flow rate of the hydrophobic sol-gel silica powder passing through the pipe. Further, the lower take-out pipe 6 and the upper take-out pipe 7 merge to form a collective take-out pipe 10. Further, a bag filter 11 for preventing the hydrophilic sol-gel silica particles 14 from being discharged together with the exhaust gas is provided on the upper portion of the cylinder body 2, and an exhaust pipe for discharging the exhaust gas is provided on the upper wall 2b of the cylinder body 2. 12 is connected. With the manual valve 8 and the flow rate adjusting valve 9 closed, a predetermined amount of hydrophilic sol-gel silica particles 14 having an average primary particle diameter in the range of 50 to 300 nm are supplied from the raw material introduction tube 3 to the cylinder body 2. A hydrophobizing agent and an inert gas are introduced into the cylinder body 2.
ここで、流動床の反応容器1に送られる不活性ガスの反応容器の横断面積当りの線速度Vは1〜12m/sの範囲に設定する。線速度が1m/s未満であると、粒子又は粉末の不活性ガスによる十分な撹拌効果が得られにくい不具合があり、一方、12m/sを越えると粒子又は粉末の飛散が生じていずれの場合も均一な表面処理が行われない不具合がある。不活性ガスの流動床の反応容器1の横断面積当りの線速度V(m/s)は、導入する不活性ガスの流量Q(m3/s)と流動床の反応容器1の筒本体2の内壁の横断面積S(m2)との比Q/Sにて算出することができる。不活性ガスの流量Q(m3/s)は、図示しないガスフローコントローラを導入管5と図示しない不活性ガスのタンクとの間に設置し、流量Qを制御することができるようになっている。 Here, the linear velocity V per cross-sectional area of the reaction vessel of the inert gas sent to the reaction vessel 1 of the fluidized bed is set in the range of 1 to 12 m / s. When the linear velocity is less than 1 m / s, there is a problem that it is difficult to obtain a sufficient stirring effect due to the inert gas of the particles or powder. On the other hand, when the linear velocity exceeds 12 m / s, the particles or powder is scattered. However, there is a problem that uniform surface treatment is not performed. The linear velocity V (m / s) per cross-sectional area of the reaction bed 1 of the fluidized bed of the inert gas depends on the flow rate Q (m 3 / s) of the inert gas to be introduced and the cylinder body 2 of the reaction vessel 1 of the fluidized bed. The ratio Q / S with the cross-sectional area S (m 2 ) of the inner wall can be calculated. The flow rate Q (m3 / s) of the inert gas can be controlled by installing a gas flow controller (not shown) between the introduction pipe 5 and an inert gas tank (not shown). .
このような構成より成る流動床の反応容器1に親水性ゾルゲルシリカ粒子14を導入管3により供給する。親水性ゾルゲルシリカ粒子14を流動床の反応容器1に入れた状態で、上記線速度Vが1〜12m/sに設定され、整流板4によって鉛直上方に整流された不活性ガスを疎水化剤とともに供給する。反応容器は図示しない加熱手段により150〜400℃の範囲に加熱することが好ましい。これにより、流動床の反応容器1内で親水性ゾルゲルシリカ粒子14が流動状態を形成しつつ、各シリカ粒子は疎水化剤と反応し疎水化される。
このとき本発明では、表面処理時、即ち流動中の親水性ゾルゲルシリカ粒子のかさ密度を流動床の反応容器1内に静置したときの親水性ゾルゲルシリカ粒子のかさ密度の0.6〜0.9倍の範囲、好ましくは0.7〜0.9倍の範囲に設定するとともに、不活性ガスの流量を制御して反応容器内で流動中の親水性ゾルゲルシリカ粒子のかさ密度を150〜300g/Lの範囲に、好ましくは200〜300g/Lの範囲に設定する。
Hydrophilic sol-gel silica particles 14 are supplied into the fluidized bed reaction vessel 1 having such a configuration through the introduction tube 3. In a state where the hydrophilic sol-gel silica particles 14 are put in the reaction vessel 1 of a fluidized bed, the linear velocity V is set to 1 to 12 m / s, and the inert gas rectified vertically by the rectifying plate 4 is used as a hydrophobizing agent. Supply with. The reaction vessel is preferably heated to 150 to 400 ° C. by a heating means (not shown). Thereby, while the hydrophilic sol-gel silica particles 14 form a fluidized state in the reaction vessel 1 of the fluidized bed, each silica particle reacts with the hydrophobizing agent to be hydrophobized.
At this time, in the present invention, the bulk density of the hydrophilic sol-gel silica particles during surface treatment, that is, the fluidized hydrophilic sol-gel silica particles in the fluidized bed reaction vessel 1 is set to 0.6 to 0 as the bulk density of the hydrophilic sol-gel silica particles. .9 times, preferably 0.7 to 0.9 times, and the flow rate of the inert gas is controlled to adjust the bulk density of the hydrophilic sol-gel silica particles flowing in the reaction vessel to 150 to It is set in the range of 300 g / L, preferably in the range of 200 to 300 g / L.
この際、表面処理を行う際にその粉末のかさ密度が静置時のかさ密度の0.6〜0.9倍とするのは、0.6倍未満であるとゾルゲルシリカ粒子が十分に流動しない不具合があり、一方0.9倍を越えると均一な表面処理ができず、結果として十分な疎水性が得られないという不具合があるからである。また、反応容器内で流動中の親水性ゾルゲルシリカ粒子のかさ密度を、150〜300g/Lの範囲とするのは150g/L未満であると表面処理時に粉末の飛散等が生じるという不具合があり、一方300g/Lを越えると粉末の凝集力が強すぎるという不具合があり、いずれの場合も均一な表面処理が行われにくい。粉末のかさ密度は、粉末を仕込んだ重量と、仕込まれた粉末がが反応容器中において占有している体積から算出することができる。
このとき、流動床の反応容器1内に静置したときの親水性ゾルゲルシリカ粒子14のかさ密度は、流動床の反応容器1の中空の底部と側壁内径が一定であるため、整流板4の水平高さからシリカ粒子の流動状態の高さを測定する。尚、流動状態中のシリカ粒子は上面が必ずしも平坦にはならないため、流動床の反応容器1内の壁面より分かる流動面の高さを複数回測定してそのの平均より算出してかさ密度を測定する。
At this time, when the surface treatment is performed, the bulk density of the powder is 0.6 to 0.9 times the bulk density at the time of standing. On the other hand, when the ratio exceeds 0.9, uniform surface treatment cannot be performed, and as a result, sufficient hydrophobicity cannot be obtained. Further, the bulk density of the hydrophilic sol-gel silica particles that are flowing in the reaction vessel is in the range of 150 to 300 g / L. If the bulk density is less than 150 g / L, there is a problem that powder scattering occurs during the surface treatment. On the other hand, if it exceeds 300 g / L, there is a problem that the cohesive force of the powder is too strong, and in any case, uniform surface treatment is difficult to be performed. The bulk density of the powder can be calculated from the weight charged with the powder and the volume occupied by the charged powder in the reaction vessel.
At this time, the bulk density of the hydrophilic sol-gel silica particles 14 when left in the fluidized bed reaction vessel 1 is constant in the hollow bottom and side wall inner diameter of the fluidized bed reaction vessel 1. The height of the fluid state of the silica particles is measured from the horizontal height. In addition, since the upper surface of the silica particles in the fluidized state does not necessarily become flat, the height of the fluidized surface ascertained from the wall surface in the reaction vessel 1 of the fluidized bed is measured a plurality of times, and the bulk density is calculated from the average thereof. taking measurement.
このように、本発明に係る第1の実施形態によれば、流動床の反応容器1内に静置したときの親水性ゾルゲルシリカ粒子14のかさ密度と流動床の反応容器1内で流動中の親水性ゾルゲルシリカ粒子14のかさ密度の範囲を不活性ガス流の線速度により設定することで、疎水化剤によって表面処理され疎水化されるシリカ粒子同士が流動状態で良好に隔離される。その結果、疎水化剤が親水性ゾルゲルシリカ粒子14と十分かつ均一に反応し、親水性ゾルゲルシリカ粒子14から粒子表面が良好に改質された疎水性ゾルゲルシリカ粉末になる。手動バルブ8を開くことによって疎水性ゾルゲルシリカ粉末を流動床の反応容器1から排出することができる。 Thus, according to the first embodiment of the present invention, the bulk density of the hydrophilic sol-gel silica particles 14 when standing in the fluidized bed reaction vessel 1 and the fluidized bed in the reaction vessel 1 are flowing. By setting the range of the bulk density of the hydrophilic sol-gel silica particles 14 based on the linear velocity of the inert gas flow, the silica particles that are surface-treated and hydrophobized by the hydrophobizing agent are well isolated in a fluidized state. As a result, the hydrophobizing agent reacts sufficiently and uniformly with the hydrophilic sol-gel silica particles 14, and the hydrophilic sol-gel silica particles 14 become hydrophobic sol-gel silica powders whose particle surfaces are well modified. The hydrophobic sol-gel silica powder can be discharged from the fluidized bed reaction vessel 1 by opening the manual valve 8.
<第2の実施形態>
第2の実施形態では、第1の実施形態で準備された親水性ゾルゲルシリカ粒子14と同様の粉末を、図2に示される反応容器15によって表面処理を行う。
図2に示すように、反応容器15は、上部に第1〜第4短管15a〜15dが接続された球状の四つ口フラスコを有する。この四つ口フラスコの第1短管15aには撹拌機16の撹拌シャフト16aが回転可能に挿通され、第2短管15bには温度計17が挿通され、更に第3短管15cには疎水化剤を不活性ガスを導入する導入管18が挿通される。また撹拌シャフト16aの下端には撹拌羽根16bが取付けられる。この四つ口フラスコに親水性ゾルゲルシリカ粒子14を入れた後に、この親水性ゾルゲルシリカ粒子14を撹拌機16により撹拌すると同時に、導入管18から疎水化剤と不活性ガスを導入する。このとき温度計17を見ながら親水性ゾルゲルシリカ粒子14の温度を120〜350℃に保つように、また後述するシリカ粒子のかさ密度を調整するように不活性ガスの流量を調整する。また第4短管15dからは親水性ゾルゲルシリカ粒子14を疎水化した後の不活性ガスが排出される。なお第4短管15dには、親水性ゾルゲルシリカ粒子14が不活性ガスとともに排出されるのを防止するためのフィルタ(図示せず)を設けることが好ましい。
<Second Embodiment>
In the second embodiment, the same powder as the hydrophilic sol-gel silica particles 14 prepared in the first embodiment is subjected to a surface treatment using the reaction vessel 15 shown in FIG.
As shown in FIG. 2, the reaction vessel 15 has a spherical four-necked flask with first to fourth short tubes 15 a to 15 d connected to the upper part. The stirrer shaft 16a of the stirrer 16 is rotatably inserted into the first short tube 15a of the four-necked flask, the thermometer 17 is inserted into the second short tube 15b, and the third short tube 15c is further hydrophobic. An introduction pipe 18 for introducing an inert gas into the agent is inserted. A stirring blade 16b is attached to the lower end of the stirring shaft 16a. After the hydrophilic sol-gel silica particles 14 are put into the four-necked flask, the hydrophilic sol-gel silica particles 14 are stirred by the stirrer 16 and at the same time, the hydrophobizing agent and the inert gas are introduced from the introduction pipe 18. At this time, the flow rate of the inert gas is adjusted so as to keep the temperature of the hydrophilic sol-gel silica particles 14 at 120 to 350 ° C. while watching the thermometer 17 and to adjust the bulk density of the silica particles described later. Further, the inert gas after the hydrophilic sol-gel silica particles 14 are hydrophobized is discharged from the fourth short tube 15d. The fourth short tube 15d is preferably provided with a filter (not shown) for preventing the hydrophilic sol-gel silica particles 14 from being discharged together with the inert gas.
第2の実施形態では、球状の反応容器である四つ口フラスコに、第1の実施形態と同様の平均一次粒子径を持つ所定量の親水性ゾルゲルシリカ粒子14を導入し、更にこの四つ口フラスコに不活性ガスを流通しつつ疎水化剤を添加し、親水性ゾルゲルシリカ粒子14を所定時間流動させることによって、本発明の表面処理方法によって親水性ゾルゲルシリカ粒子14を疎水化することができる。 In the second embodiment, a predetermined amount of hydrophilic sol-gel silica particles 14 having the same average primary particle diameter as in the first embodiment are introduced into a four-necked flask that is a spherical reaction vessel, and these four Hydrophobizing agent is added to the mouth flask while flowing the inert gas, and the hydrophilic sol-gel silica particles 14 are hydrophobized by the surface treatment method of the present invention by flowing the hydrophilic sol-gel silica particles 14 for a predetermined time. it can.
第2の実施形態では、反応容器の形状が第1の実施形態の反応容器(図1)の形状と異なるけれども、第1の実施形態と基本的に疎水化剤の親水性ゾルゲルシリカ粒子14への表面処理方法は同様にして行う。第1の実施形態では、親水性ゾルゲルシリカ粒子14の流動を不活性ガスの供給によって創出しているのに対して、第2の実施形態では不活性ガスの供給とともに撹拌羽根16bの回転によって上記流動を創出している。このため、かさ密度を本発明の範囲に設定するためには、不活性ガスの供給量と撹拌羽根の回転数を制御する。親水性ゾルゲルシリカ粒子14の流動状態の上部中央箇所は、撹拌羽根16bの撹拌シャフト16aに沿って下に窪むため、流動中のシリカ粒子のかさ密度は反応容器15内の壁面より分かる流動面凸部分の高さと中央部にある撹拌シャフト16aの流動部凹部分の高さ平均より算出して測定する。また第2の実施形態では、不活性ガスの線速度を求めるときの反応容器であるフラスコの横断面積はフラスコの最大径に相当する横断面積とする。 In the second embodiment, the shape of the reaction vessel is different from the shape of the reaction vessel (FIG. 1) of the first embodiment, but basically the hydrophilic sol-gel silica particles 14 of the hydrophobizing agent as in the first embodiment. The surface treatment method is performed in the same manner. In the first embodiment, the flow of the hydrophilic sol-gel silica particles 14 is created by supplying an inert gas, whereas in the second embodiment, the above-described operation is performed by rotating the stirring blade 16b together with the supply of the inert gas. Creating a flow. For this reason, in order to set the bulk density within the range of the present invention, the supply amount of the inert gas and the rotation speed of the stirring blade are controlled. Since the upper central portion of the fluid state of the hydrophilic sol-gel silica particles 14 is depressed downward along the stirring shaft 16a of the stirring blade 16b, the bulk density of the silica particles during the flow can be understood from the wall surface in the reaction vessel 15. It is calculated by calculating from the height of the convex portion and the average height of the flow portion concave portion of the stirring shaft 16a in the central portion. Moreover, in 2nd Embodiment, the cross-sectional area of the flask which is a reaction container when calculating | requiring the linear velocity of an inert gas is taken as the cross-sectional area equivalent to the maximum diameter of a flask.
更に第1の実施形態又は第2の実施形態において、上記流動状態を維持しながら、疎水化剤を噴霧又は気化及び加熱しながら親水性ゾルゲルシリカ粒子と反応させるようにしてもよい。このとき、水、アミン、その他触媒を使用しても良い。この場合も窒素などの不活性ガス雰囲気下で行うことが望ましい。或いは溶剤に疎水化剤を溶解し、これを親水性ゾルゲルシリカ粒子と混合・分散した後、必要に応じて加熱処理を行いながら上記のような乾式法を採用し疎水性ゾルゲルシリカ粉末を得ることもできる。この場合、加熱処理条件は特に限定されないが一般的には、加熱温度120〜350℃、加熱時間10〜200分程度の条件が採用される。加熱温度が、120℃未満であると有機ケイ素化合物の十分な表面処理が行われず高い疎水性が得られない不具合があり、一方、350℃を越えると有機ケイ素化合物の一部分解が生じうる不具合があるためである。 Furthermore, in the first embodiment or the second embodiment, the hydrophobizing agent may be reacted with the hydrophilic sol-gel silica particles while being sprayed or vaporized and heated while maintaining the fluid state. At this time, water, amine, and other catalysts may be used. Also in this case, it is desirable to carry out in an inert gas atmosphere such as nitrogen. Alternatively, a hydrophobizing agent is dissolved in a solvent, mixed and dispersed with hydrophilic sol-gel silica particles, and then subjected to a heat treatment as necessary to obtain a hydrophobic sol-gel silica powder by adopting the dry method as described above. You can also. In this case, the heat treatment conditions are not particularly limited, but generally, a heating temperature of 120 to 350 ° C. and a heating time of about 10 to 200 minutes are employed. If the heating temperature is less than 120 ° C, sufficient surface treatment of the organosilicon compound is not performed and high hydrophobicity cannot be obtained. On the other hand, if the heating temperature exceeds 350 ° C, the organosilicon compound may partially decompose. Because there is.
次に、本発明で得られる疎水化シリカ粉末の特徴について説明する。
先ず、本発明で得られる疎水化シリカ粉末の乾燥減量は0.8質量%以下であることが好ましい。この乾燥減量は105℃、2時間加熱後の加熱前の重量変化から測定する。乾燥減量が0.8質量%を越えると、疎水化のための表面処理中の水分、溶媒が疎水性シリカ粉末中に残留していることになり、電荷の安定性、あるいはトナーの外添剤として使用した場合に揮,個発成分を発する等の不具合があり好ましくない。乾燥減量は更に0.6質量%以下であることが好ましい。上記不具合が更に防止されるからである。
Next, the characteristics of the hydrophobized silica powder obtained by the present invention will be described.
First, the loss on drying of the hydrophobized silica powder obtained in the present invention is preferably 0.8% by mass or less. This loss on drying is measured from the change in weight before heating after heating at 105 ° C. for 2 hours. If the weight loss after drying exceeds 0.8% by mass, water and solvent during the surface treatment for hydrophobization remain in the hydrophobic silica powder, and charge stability or external toner additives When used as, there is a problem such as emission of volatilization and individual components, which is not preferable. The loss on drying is preferably 0.6% by mass or less. This is because the above problems are further prevented.
また、本発明で得られる疎水性シリカ粉末の疎水性は70〜100%の範囲にあることが好ましい。この疎水性は電荷の安定性と関係しており、疎水性が、70%未満であると電荷の十分な環境安定性や表面処理中にシリカ粒子の流動性得られない不具合があり、一方、95%を越えるためには疎水化処理に多大のエネルギーと時間を必要とする。疎水性は更に95〜100%の範囲にあることが好ましい。上記不具合が更に防止されるからである。 The hydrophobicity of the hydrophobic silica powder obtained in the present invention is preferably in the range of 70 to 100%. This hydrophobicity is related to the stability of the charge, and if the hydrophobicity is less than 70%, there is a problem that sufficient environmental stability of the charge and fluidity of the silica particles cannot be obtained during the surface treatment, In order to exceed 95%, enormous energy and time are required for the hydrophobization treatment. The hydrophobicity is preferably in the range of 95 to 100%. This is because the above problems are further prevented.
更に、本発明で得られる疎水性シリカ粉末の有機溶剤抽出分の含有炭素分は、単位面積当り0.001〜0.03質量%/m2の範囲にあることが好ましい。炭素量が単位面積当り0.001質量%/m2未満では、有機物による十分な表面処理が行われず一般に帯電安定性、分散性等が不十分となりがちとなる不具合があり、一方、0.03質量%/m2を越えると、有機物の含有量が多すぎ逆に凝集等が生じ、十分な分散性が得られない場合が多く、結果としてこの疎水性シリカ粉末をトナーの外添剤に応用したとき、十分な画像品質が得られない不具合があり好ましくない。 Furthermore, the carbon content contained in the organic solvent extract of the hydrophobic silica powder obtained in the present invention is preferably in the range of 0.001 to 0.03% by mass / m 2 per unit area. When the amount of carbon is less than 0.001% by mass / m 2 per unit area, sufficient surface treatment with an organic substance is not performed, and there is a problem that generally charging stability and dispersibility tend to be insufficient. If it exceeds mass% / m 2 , the organic content is too high, and on the contrary, aggregation or the like will occur and sufficient dispersibility may not be obtained in many cases. As a result, this hydrophobic silica powder is applied as an external additive for toner. However, there is a problem that sufficient image quality cannot be obtained, which is not preferable.
<静電荷現像用トナー>
次に、疎水性ゾルゲルシリカ粉末をトナーの外添剤にした静電荷現像用トナーについて説明する。
トナーには一般的に熱可塑性樹脂(トナー母体樹脂)の他、少量の顔料及び電荷制御剤、その他の外添剤が含まれているけれども、本発明では本発明の疎水性ゾルゲルシリカ粉末が配合されていれば、他の成分は従来と同様で良く、磁性、非磁性の一成分系トナー、二成分系トナーのいずれでも良い。また、負帯電性トナー、正帯電性トナーのいずれでも良く、モノクロ、カラーのどちらでも良い。またトナーの組成やその製造方法には特に制限はなく、公知の組成及び方法を採用することができる。
<Toner for electrostatic charge development>
Next, an electrostatic charge developing toner using a hydrophobic sol-gel silica powder as an external additive of the toner will be described.
The toner generally contains a small amount of a pigment, a charge control agent, and other external additives in addition to a thermoplastic resin (toner base resin), but in the present invention, the hydrophobic sol-gel silica powder of the present invention is blended. As long as the other components are used, the other components may be the same as those in the past, and may be either magnetic or non-magnetic one-component toner or two-component toner. Further, either negatively chargeable toner or positively chargeable toner may be used, and either monochrome or color may be used. There are no particular restrictions on the toner composition and its production method, and known compositions and methods may be employed.
本発明の静電荷現像用トナーの製造に当り、本発明の疎水性ゾルゲルシリカ粉末の静電荷現像用トナーの外添剤としての添加量は、所望の特性向上効果が得られるような添加量であれば良く特に制限されていないけれども、静電荷現像用トナー中に本発明の疎水性ゾルゲルシリカ粉末が0.1〜8.0質量%含有されていることが好ましい。疎水性ゾルゲルシリカ粉末の含有量が0.1質量%未満では、本発明の疎水性ゾルゲルシリカ粉末を添加したことによる耐久性の向上効果や帯電性等安定効果が十分に得られない不具合があり、一方、疎水性ゾルゲルシリカ粉末の含有量が8.0質量%を越えるとトナーの表面を完全に被覆してなお過剰のシリカ粒子が多く存在するため、反応容器等の装置内汚染の原因になりえる不具合があるためである。 In the production of the electrostatic charge developing toner of the present invention, the amount of the hydrophobic sol-gel silica powder of the present invention added as an external additive of the electrostatic charge developing toner is such that a desired characteristic improving effect can be obtained. Although there is no particular limitation as long as it is present, it is preferable that 0.1 to 8.0% by mass of the hydrophobic sol-gel silica powder of the present invention is contained in the toner for electrostatic charge development. If the content of the hydrophobic sol-gel silica powder is less than 0.1% by mass, there is a problem that the effect of improving the durability and the stabilizing effect such as charging property cannot be sufficiently obtained by adding the hydrophobic sol-gel silica powder of the present invention. On the other hand, if the content of the hydrophobic sol-gel silica powder exceeds 8.0% by mass, the surface of the toner is completely covered and a large amount of excessive silica particles are still present, which may cause contamination in the apparatus such as the reaction vessel. This is because there is a possible defect.
更に、本発明の静電荷現像用トナーの製造にあたり、外添剤としての本発明の疎水性ゾルゲルシリカ粉末は、単独で使用されるに限らず、目的に応じて、他の金属酸化物粉末と併用しても良い。例えば、本発明の疎水性ゾルゲルシリカ粉末と、他の方法で表面改質された乾式シリカ粒子や表面改質された乾式チタン粒子や表面改質された乾式アルミナ粒子等を併用することができる。 Furthermore, in the production of the electrostatic charge developing toner of the present invention, the hydrophobic sol-gel silica powder of the present invention as an external additive is not limited to being used alone, but may be used with other metal oxide powders depending on the purpose. You may use together. For example, the hydrophobic sol-gel silica powder of the present invention can be used in combination with dry silica particles surface modified by other methods, dry titanium particles surface modified or dry alumina particles surface modified.
次に本発明の実施例を比較例と共に詳しく説明する。以下の実施例、比較例では不活性ガスとして窒素を用いた。
<実施例1>
実施例1では、図2に示すような、容積が3Lの四つ口フラスコの反応容器15を用いて表1に示す処理条件で表面処理を行った。より具体的には、滴下ロート(2個)、撹拌機、温度計を備えた3L容量の四つ口フラスコに、メタノール700mL、イオン交換水40mL、28質量%濃度のアンモニア水50gを入れた。得られた溶液を35℃にて撹拌しながらテトラエトキシシラン1590g及び5質量%濃度の希釈アンモニア水420gを同時に添加し、テトラエトキシシランは5時間、希釈アンモニア水は4時間にわたりそれぞれ滴下した。滴下終了後、更に2間撹拌を継続した。ついで上記反応溶液をエバポレーターにて70℃に加熱しながら溶媒を減圧留去することにより粗ゾルゲルシリカ粉末を得た。ついで、この粗ゾルゲルシリカ粉末を800℃、3時間の熱処理を行うことにより、親水性ゾルゲルシリカ粒子450gを得た。
次に親水性ゾルゲルシリカ粒子の疎水化処理を行った。この親水性ゾルゲルシリカ粒子の特性とこの親水性ゾルゲルシリカ粒子の表面処理条件を表1に示す。
なお、表1に示す「疎水化剤仕込み量(部数」とは、反応容器に親水性ゾルゲルシリカ粒子の質量部を100とするときに添加された疎水化剤の質量部である。具体的には上記親水性ゾルゲルシリカ粒子300gを3L容量の四つ口フラスコに入れ、窒素ガス雰囲気下、疎水化剤としてヘキサメチルジシラザン(以下、HMDSという。)50gを窒素ガスとともに四つ口フラスコに導入し、次にこの反応混合物を250℃に昇温し2時間加熱しながら窒素ガスの線速度を8.7(m/s)に設定しかつ撹拌回転数800(rpm)で撹拌した。このようにして疎水性ゾルゲルシリカ粉末を得た。得られたシリカ粉末の粉末特性結果を表2に示す。
Next, examples of the present invention will be described in detail together with comparative examples. In the following examples and comparative examples, nitrogen was used as an inert gas.
<Example 1>
In Example 1, the surface treatment was performed under the treatment conditions shown in Table 1 using a reaction vessel 15 of a four-necked flask having a volume of 3 L as shown in FIG. More specifically, 700 mL of methanol, 40 mL of ion-exchanged water, and 50 g of 28 mass% ammonia water were placed in a 3 L four-necked flask equipped with a dropping funnel (2), a stirrer, and a thermometer. While stirring the resulting solution at 35 ° C., 1590 g of tetraethoxysilane and 420 g of diluted ammonia water having a concentration of 5% by mass were added simultaneously, and tetraethoxysilane was added dropwise over 5 hours and diluted ammonia water over 4 hours. After completion of the dropwise addition, stirring was further continued for 2 minutes. Next, the solvent was distilled off under reduced pressure while heating the reaction solution to 70 ° C. with an evaporator to obtain a crude sol-gel silica powder. Next, the crude sol-gel silica powder was heat treated at 800 ° C. for 3 hours to obtain 450 g of hydrophilic sol-gel silica particles.
Next, the hydrophilic sol-gel silica particles were hydrophobized. Table 1 shows the characteristics of the hydrophilic sol-gel silica particles and the surface treatment conditions of the hydrophilic sol-gel silica particles.
The “hydrophobizing agent charge amount (parts)” shown in Table 1 is the mass part of the hydrophobizing agent added to the reaction vessel when the mass part of the hydrophilic sol-gel silica particles is 100. Specifically, Put 300 g of the above hydrophilic sol-gel silica particles into a 3 L four-necked flask and introduce 50 g of hexamethyldisilazane (hereinafter referred to as HMDS) as a hydrophobizing agent into the four-necked flask together with nitrogen gas in a nitrogen gas atmosphere. Then, the reaction mixture was heated to 250 ° C. and heated for 2 hours while setting the linear velocity of nitrogen gas to 8.7 (m / s) and stirring at a stirring speed of 800 (rpm). Thus, a hydrophobic sol-gel silica powder was obtained, and the powder characteristic results of the obtained silica powder are shown in Table 2.
<実施例2、4、5>
実施例2、4、5では、実施例1と同様に図2に示す反応容器15を用いて表1に示す処理条件で表面処理を行った。また実施例2、4、5では、実施例1の親水性ゾルゲルシリカ粒子の代わりに平均一次粒子径が110nmの市販の親水性ゾルゲルシリカ粉末(A社製シリカ)を用い、また不活性ガスとして窒素ガスを用い、更に表1に示す疎水化剤を用いて、表1に示す表面処理条件でこのシリカ粉末を疎水化した。得られた疎水性ゾルゲルシリカ粉末の粉末特性結果を表2に示す。また実施例2で得られた疎水性ゾルゲルシリカ粉末とトナーとを混合した際のSEM観察像を図3に示す。実施例2、4、5では、親水性ゾルゲルシリカ粉末の疎水化処理に際し、撹拌回転数と窒素ガスの線速度とを変えながら、実施例1と同様の操作を行った。ただし、実施例5は事前に上記親水性ゾルゲルシリカ粒子Aの粉末を圧密することでかさ密度を上げた。このようにして実施例2、4、5の疎水性ゾルゲルシリカ粉末を得た。得られたシリカ粉末の粉末特性結果を表2に示す。
<Examples 2, 4, and 5>
In Examples 2, 4, and 5, the surface treatment was performed under the treatment conditions shown in Table 1 using the reaction vessel 15 shown in FIG. In Examples 2, 4, and 5, a commercially available hydrophilic sol-gel silica powder having an average primary particle size of 110 nm (silica manufactured by Company A) was used in place of the hydrophilic sol-gel silica particles of Example 1, and as an inert gas. This silica powder was hydrophobized under the surface treatment conditions shown in Table 1 using nitrogen gas and further using a hydrophobizing agent shown in Table 1. Table 2 shows the powder characteristic results of the obtained hydrophobic sol-gel silica powder. FIG. 3 shows an SEM observation image obtained when the hydrophobic sol-gel silica powder obtained in Example 2 and the toner are mixed. In Examples 2, 4, and 5, the same operation as in Example 1 was performed while changing the rotation speed of stirring and the linear velocity of nitrogen gas during the hydrophobization treatment of the hydrophilic sol-gel silica powder. However, in Example 5, the bulk density was increased by consolidating the powder of the hydrophilic sol-gel silica particles A in advance. In this way, hydrophobic sol-gel silica powders of Examples 2, 4, and 5 were obtained. Table 2 shows the powder characteristic results of the obtained silica powder.
<実施例3>
実施例3では、図1に示すような、容積が10Lの流動床の反応容器1を用いて表1に示す処理条件で表面処理を行った。より詳細には原料導入管3から平均一次粒子径が110nmの市販の親水性ゾルゲルシリカ粉末(A社製シリカ)500gを導入した。この導入されたシリカ粉末は整流板4上に載った状態に保持された。反応容器1の底壁2aに形成されたガス導入管5から窒素ガスとともに表1に示す疎水化剤75gを反応容器1内に導入した。この窒素ガスは疎水化剤のキャリアガスとして用いられるとともに、シリカ粉末の流動化ガスとしても用いられる。窒素ガスにより搬送された疎水化剤がシリカ粉末に接触すると、化学反応によりシリカ粉末の表面が疎水化した。次に上記反応容器1に窒素ガスを導入しながら180℃で1時間保持した後に、上記酸化物粉末を手動バルブ8を開いて下側取出し管6から取出した。このようにして実施例3の疎水性ゾルゲルシリカ粉末を得た。得られたシリカ粉末の粉末特性結果を表2に示す。
<Example 3>
In Example 3, the surface treatment was performed under the treatment conditions shown in Table 1 using a reaction vessel 1 having a volume of 10 L as shown in FIG. More specifically, 500 g of a commercially available hydrophilic sol-gel silica powder (silica manufactured by Company A) having an average primary particle size of 110 nm was introduced from the raw material introduction tube 3. The introduced silica powder was held on the current plate 4. 75 g of the hydrophobizing agent shown in Table 1 was introduced into the reaction vessel 1 together with nitrogen gas from the gas introduction pipe 5 formed on the bottom wall 2a of the reaction vessel 1. This nitrogen gas is used as a carrier gas for the hydrophobizing agent and also as a fluidizing gas for the silica powder. When the hydrophobizing agent conveyed by nitrogen gas contacted the silica powder, the surface of the silica powder was hydrophobized by a chemical reaction. Next, nitrogen gas was introduced into the reaction vessel 1 and held at 180 ° C. for 1 hour, and then the oxide powder was taken out from the lower take-out pipe 6 by opening the manual valve 8. In this way, a hydrophobic sol-gel silica powder of Example 3 was obtained. Table 2 shows the powder characteristic results of the obtained silica powder.
<実施例6>
実施例6は、実施例3と同様に図1に示す反応容器1を用いて表1に示す処理条件で表面処理を行った。但し、実施例3の親水性ゾルゲルシリカ粒子の代わりに、実施例6では平均一次粒子径が75nmの市販の親水性ゾルゲルシリカ粉末(B社製シリカ)を用いた。
<Example 6>
In Example 6, surface treatment was performed under the treatment conditions shown in Table 1 using the reaction vessel 1 shown in FIG. However, instead of the hydrophilic sol-gel silica particles of Example 3, in Example 6, a commercially available hydrophilic sol-gel silica powder (silica manufactured by B company) having an average primary particle size of 75 nm was used.
<実施例7>
実施例7では、実施例1と同様に図2に示す反応容器15を用いて表1に示す処理条件で表面処理を行った。実施例7では平均一次粒子径が220nmの市販の親水性ゾルゲルシリカ粉末(B社製シリカ)を用いた。また表1に示す疎水化剤を用いて、表1に示す表面処理条件で上記シリカ粒子を疎水化処理した。得られたシリカ粉末の粉末特性結果を表2に示した。実施例7では、親水性ゾルゲルシリカ粉末の疎水化処理に際し、撹拌回転数と窒素ガスの線速度とを変えながら、図2に示す反応容器15を用いて表1に示す表面処理条件で表面処理を行った。
<Example 7>
In Example 7, surface treatment was performed under the treatment conditions shown in Table 1 using the reaction vessel 15 shown in FIG. In Example 7, a commercially available hydrophilic sol-gel silica powder (silica manufactured by B company) having an average primary particle size of 220 nm was used. Further, the silica particles were hydrophobized using the hydrophobizing agent shown in Table 1 under the surface treatment conditions shown in Table 1. Table 2 shows the powder characteristic results of the obtained silica powder. In Example 7, in the hydrophobization treatment of the hydrophilic sol-gel silica powder, the surface treatment was carried out under the surface treatment conditions shown in Table 1 using the reaction vessel 15 shown in FIG. 2 while changing the rotation speed of stirring and the linear velocity of nitrogen gas. Went.
<比較例1>
比較例1では、実施例1と同様に図2に示す反応容器15を用いて表1に示す処理条件で表面処理を行った。即ち実施例1と同様の方法で製造された親水性ゾルゲルシリカ粒子を疎水化処理した。この際、撹拌回転数と窒素ガスの線速度を変えた。他の表面処理条件は実施例1と同様の条件で行った。得られたシリカ粉末の粉末特性結果を表2に示す。
<Comparative Example 1>
In Comparative Example 1, the surface treatment was performed under the treatment conditions shown in Table 1 using the reaction vessel 15 shown in FIG. That is, the hydrophilic sol-gel silica particles produced by the same method as in Example 1 were subjected to a hydrophobic treatment. At this time, the rotation speed of stirring and the linear velocity of nitrogen gas were changed. Other surface treatment conditions were the same as in Example 1. Table 2 shows the powder characteristic results of the obtained silica powder.
<比較例2、4、5>
比較例2、4及び5では、実施例1と同様に図2に示す反応容器15を用いて表1に示す処理条件で表面処理を行った。また比較例2、4及び5では、実施例2、4及び5で用いた市販の親水性ゾルゲルシリカ粒子をそれぞれ用いた。また、表1に示す疎水化剤を用いて、表1に示す表面処理条件で上記シリカ粒子を疎水化処理した。得られたシリカ粉末の粉末特性結果を表2に示す。実施例2〜5では親水性ゾルゲルシリカ粒子の疎水化処理に際し、撹拌回転数及び窒素ガスの線速度を変えた。他の条件は実施例2〜5と同様の条件で行った。
また比較例2の条件で得られた疎水性ゾルゲルシリカ粉末とトナーとを混合したSEM観察結果(10,000倍)を図4に示した。図4の中央に分散しなかったシリカ凝集体が観察された。
<Comparative Examples 2, 4, 5>
In Comparative Examples 2, 4, and 5, the surface treatment was performed under the treatment conditions shown in Table 1 using the reaction vessel 15 shown in FIG. In Comparative Examples 2, 4 and 5, commercially available hydrophilic sol-gel silica particles used in Examples 2, 4 and 5 were used, respectively. Further, the silica particles were hydrophobized using the hydrophobizing agent shown in Table 1 under the surface treatment conditions shown in Table 1. Table 2 shows the powder characteristic results of the obtained silica powder. In Examples 2 to 5, during the hydrophobization treatment of the hydrophilic sol-gel silica particles, the stirring rotation speed and the linear velocity of nitrogen gas were changed. Other conditions were the same as those in Examples 2 to 5.
Further, FIG. 4 shows the SEM observation result (10,000 times) obtained by mixing the hydrophobic sol-gel silica powder obtained under the condition of Comparative Example 2 and the toner. Silica aggregates that were not dispersed in the center of FIG. 4 were observed.
<比較例3>
比較例3は、実施例3と同様に図1に示す反応容器1を用いて表1に示す処理条件で表面処理を行った。但し、比較例3では、実施例2、4及び5で用いた市販の親水性ゾルゲルシリカ粒子をそれぞれ用いた。。
<Comparative Example 3>
In Comparative Example 3, the surface treatment was performed under the treatment conditions shown in Table 1 using the reaction vessel 1 shown in FIG. However, in Comparative Example 3, commercially available hydrophilic sol-gel silica particles used in Examples 2, 4 and 5 were used. .
<比較例6>
比較例6では、実施例1と同様に図2に示す反応容器15を用いて表1に示す処理条件で表面処理を行った。但し、比較例6では、実施例1の親水性ゾルゲルシリカ粒子の代わりに平均一次粒子径が100nmの市販の親水性ゾルゲル粒子(A社製シリカ)を用いた。また表1に示す疎水化剤を用いて表1に示す表面処理条件で上記シリカ粒子を疎水化処理した。
<Comparative Example 6>
In Comparative Example 6, the surface treatment was performed under the treatment conditions shown in Table 1 using the reaction vessel 15 shown in FIG. However, in Comparative Example 6, commercially available hydrophilic sol-gel particles (silica manufactured by Company A) having an average primary particle size of 100 nm were used in place of the hydrophilic sol-gel silica particles of Example 1. The silica particles were hydrophobized using the hydrophobizing agent shown in Table 1 under the surface treatment conditions shown in Table 1.
<比較例7>
比較例7では、実施例3と同様に図1に示す反応容器1を用い実施例3と同じ処理条件とした。但し、実施例3の親水性ゾルゲルシリカ粒子の代わりに、比較例7では平均一次粒子径が30nmの市販の親水性ゾルゲル粒子(A社製シリカ)を用いた。また表1に示す疎水化剤を用いて表1に示す表面処理条件で上記シリカ粒子を疎水化処理した。
<Comparative Example 7>
In Comparative Example 7, as in Example 3, the reaction vessel 1 shown in FIG. However, instead of the hydrophilic sol-gel silica particles of Example 3, in Comparative Example 7, commercially available hydrophilic sol-gel particles (silica manufactured by Company A) having an average primary particle size of 30 nm were used. The silica particles were hydrophobized using the hydrophobizing agent shown in Table 1 under the surface treatment conditions shown in Table 1.
<比較例8>
比較例8では、実施例1と同様に図2に示す反応容器15を用いて表1に示す処理条件で表面処理を行った。但し、実施例1の親水性ゾルゲルシリカ粒子の代わりに平均一次粒子径が500nmの市販の親水性ゾルゲル粒子(A社製シリカ)を用いた。また表1に示す疎水化剤を用いて、表1に示す表面処理条件で上記シリカ粒子を疎水化処理した。得られたシリカ粉末の粉末特性結果を表2に示す。比較例8、9では親水性ゾルゲルシリカ粒子の疎水化処理に際し、撹拌回転数及び窒素ガスの線速度を変えた。
<Comparative Example 8>
In Comparative Example 8, surface treatment was performed under the treatment conditions shown in Table 1 using the reaction vessel 15 shown in FIG. However, instead of the hydrophilic sol-gel silica particles of Example 1, commercially available hydrophilic sol-gel particles (silica manufactured by Company A) having an average primary particle size of 500 nm were used. Further, the silica particles were hydrophobized using the hydrophobizing agent shown in Table 1 under the surface treatment conditions shown in Table 1. Table 2 shows the powder characteristic results of the obtained silica powder. In Comparative Examples 8 and 9, during the hydrophobization treatment of the hydrophilic sol-gel silica particles, the stirring rotation speed and the linear velocity of nitrogen gas were changed.
<比較例9>
比較例9では、実施例3と同様に図1に示す反応容器1を用い実施例3と同じ処理条件とした。但し、実施例3の親水性ゾルゲルシリカ粒子の代わりに、比較例9では平均一次粒子径が500nmの市販の親水性ゾルゲル粒子(A社製シリカ)を用いた。また表1に示す疎水化剤を用いて表1に示す表面処理条件で上記シリカ粒子を疎水化処理した。
<Comparative Example 9>
In Comparative Example 9, as in Example 3, the reaction vessel 1 shown in FIG. However, instead of the hydrophilic sol-gel silica particles of Example 3, in Comparative Example 9, commercially available hydrophilic sol-gel particles (silica manufactured by Company A) having an average primary particle diameter of 500 nm were used. The silica particles were hydrophobized using the hydrophobizing agent shown in Table 1 under the surface treatment conditions shown in Table 1.
表1及び表2の、平均一次粒子径、かさ密度の比、疎水化剤仕込み量、疎水性、乾燥減量及びカーボン量は、以下の方法による。 The average primary particle diameter, bulk density ratio, hydrophobizing agent charge, hydrophobicity, loss on drying and carbon content in Tables 1 and 2 are as follows.
「平均一次粒子径」は、110nm未満のシリカ粒子では透過型電子顕微鏡(300,000倍)で撮影し、110nm以上のシリカ粒子では走査型電子顕微鏡(50,000倍)で撮影した。その写真図中のシリカ粒子について、無作為に50個以上の粒子径を測定しその平均をとった値である。
「かさ密度の比」は、表面処理時のかさ密度Yに対する静置時のかさ密度Xの比Y/Xである。
「撹拌回転数(rpm)」は、撹拌機を駆動するモータの回転数である。
「疎水性」は、疎水性ゾルゲルシリカ粉末のサンプル1gを200mLの分液ロートに計り採り、これに純水100mLを加えて栓をし、ターブラーミキサーで90rpmの撹拌回転数で10分間振盪し、振盪後、10分間静置する。静置後、下層の20〜30mLをロートから抜き取った後に、下層の混合液を10mm石英セルに分取し、純水をブランクとして、比色計にかけ、波長500nmでの光透過率(%)を疎水率(%)とする。
「乾燥減量」は、十分に乾燥した秤量瓶の重量を測定し(重量:A)、表面改質シリカ粉末をその秤量瓶にサンプリングし重量を測定する(重量:B)。恒温乾燥機を使用し105℃で2時間乾燥する。乾燥終了後、デシケータに移し、15分間放冷し、放冷後の重量を測定する(重量:C)。そして、次式により水分(質量%)を測定し、これを乾燥減量(質量%)する。
水分(質量%)={(B−C)/(B−A)}×100
The “average primary particle size” was taken with a transmission electron microscope (300,000 times) for silica particles of less than 110 nm, and with a scanning electron microscope (50,000 times) for silica particles of 110 nm or more. About the silica particle in the photograph figure, it is the value which measured the particle diameter of 50 or more at random, and took the average.
The “bulk density ratio” is the ratio Y / X of the bulk density X at the time of standing to the bulk density Y at the time of surface treatment.
The “stirring rotational speed (rpm)” is the rotational speed of the motor that drives the stirrer.
“Hydrophobic” refers to a sample of 1 g of hydrophobic sol-gel silica powder, weighed in a 200 mL separatory funnel, added 100 mL of pure water, capped, and shaken with a tumbler mixer at a stirring speed of 90 rpm for 10 minutes. Let stand for 10 minutes after shaking. After standing, after removing 20-30 mL of the lower layer from the funnel, the lower layer mixed solution is dispensed into a 10 mm quartz cell, subjected to a colorimeter using pure water as a blank, and light transmittance at a wavelength of 500 nm (%) Is the hydrophobic rate (%).
“Weight loss” measures the weight of a sufficiently dried weighing bottle (weight: A), samples the surface-modified silica powder into the weighing bottle, and measures the weight (weight: B). Dry at 105 ° C. for 2 hours using a constant temperature dryer. After completion of drying, the product is transferred to a desiccator, allowed to cool for 15 minutes, and the weight after cooling is measured (weight: C). Then, the moisture (mass%) is measured by the following formula, and the weight loss is reduced (mass%).
Moisture (mass%) = {(BC) / (BA)} × 100
「カーボン量」は、有機溶剤抽出分の含有炭素分であり、炭素分析装置(SUMIGRAPH NC−22、(株)住化分析センター製)を用いて以下のように測定する。秤量を完了した標準試料及び測定試料の入ったボートを装置にセットし、測定を開始する。測定データ処理プログラムにて最終結果まで自動計算される。そのときに自動計算されたカーボン値を評価する。カーボン量を測定する際は、事前に表面処理された試料をソックスレー抽出を行った試料で測定を行った。ソックスレー抽出は、抽出に用いる溶媒を加熱する毎に蒸留し、試料を入れた部分で受け取り、蒸留された溶媒の量が増えるにつれて、サイホンの原理により必要量以上に溜まった溶媒は全て蒸留前のフラスコに戻るが、その間に試料からの抽出する操作である。 “Carbon amount” is a carbon content contained in an organic solvent extract, and is measured as follows using a carbon analyzer (SUMIGRAPH NC-22, manufactured by Sumika Chemical Analysis Co., Ltd.). A boat containing a standard sample and a measurement sample for which weighing has been completed is set in the apparatus, and measurement is started. The measurement data processing program automatically calculates the final result. At that time, the automatically calculated carbon value is evaluated. When measuring the amount of carbon, the sample surface-treated in advance was measured with a sample subjected to Soxhlet extraction. In Soxhlet extraction, the solvent used for extraction is distilled each time it is heated, and is received at the portion where the sample is placed.As the amount of the distilled solvent increases, all of the solvent accumulated by the Siphon principle exceeds the required amount. The operation returns to the flask, and the sample is extracted from the sample in the meantime.
更に、各実施例及び比較例の疎水性ゾルゲル粉末から得られた静電荷現像用トナーを評価した。この評価はSEM観察とトナー評価による。
SEM観察ではトナー表面のシリカ分散性の評価を評価した。重合法により製造された市販の負帯電ポリエステルトナー母体粉末(Sinonar社製)を使用し、このトナーを実施例及び比較例に示す表面改質シリカ粉末と97:3の重量比で混合し、ヘンシェル型ミキサーで600rpm、1分間予備混合を行った後、3000rpm、3分間混合させることによって、分散性評価用のサンプルを調整し、SEMにて10,000倍により観察した。観察結果を分散性の良い順に「優」、「可」、「不可」と評価した。
Further, electrostatic charge developing toners obtained from the hydrophobic sol-gel powders of Examples and Comparative Examples were evaluated. This evaluation is based on SEM observation and toner evaluation.
In SEM observation, evaluation of silica dispersibility on the toner surface was evaluated. Using a commercially available negatively charged polyester toner base powder (manufactured by Sinnar) manufactured by a polymerization method, this toner was mixed with the surface-modified silica powder shown in Examples and Comparative Examples at a weight ratio of 97: 3, and Henschel After premixing for 1 minute at 600 rpm with a mold mixer, a sample for evaluation of dispersibility was prepared by mixing for 3 minutes at 3000 rpm, and observed with a SEM at a magnification of 10,000 times. The observation results were evaluated as “excellent”, “possible”, and “impossible” in order of good dispersibility.
トナー評価は印刷テストによって評価した。重合法により製造された市販の負帯電ポリエステルトナー母体粉末(Sinonar社製)からなるトナー3重量部を使用し、このトナーを実施例及び比較例に示す表面改質シリカ粉末と97:3の重量比で混合し、ヘンシェル型ミキサーで600rpm、1分間予備混合を行った後、3000rpm、3分間混合させた。更にこの混合粉末とキャリア用のフェライト(FL100:パウダーテック社製)97重量部とを混合して2成分現像剤を作成し、この現像剤を有機感光体を備えた2成分現像機に入れ、2万枚の印刷テストを実施した。この時、感光体へのトナーの付着は全ベタ画像での白抜けとして感知でき、感光体磨耗は画像の乱れとして感知できる。白抜けの程度は白抜けの箇所の数が10個以上/cm2、4〜9個/cm2、1〜3個/cm2、0個/cm2の段階に分け、また画像の乱れのないもの、大きな画像の乱れの無いもの、画像の乱れがあるものを総合的に評価して良い順に「優」、「良」、「可」、「不可」と評価した。 Toner evaluation was evaluated by a printing test. Using 3 parts by weight of a toner made of a commercially available negatively charged polyester toner base powder (manufactured by Sinnar) manufactured by a polymerization method, this toner was used with the surface-modified silica powder shown in Examples and Comparative Examples and a weight of 97: 3. The mixture was mixed at a ratio, premixed at 600 rpm for 1 minute with a Henschel mixer, and then mixed at 3000 rpm for 3 minutes. Further, this mixed powder and 97 parts by weight of ferrite for carrier (FL100: manufactured by Powdertech) are mixed to prepare a two-component developer, and this developer is put into a two-component developer equipped with an organic photoreceptor, A printing test of 20,000 sheets was performed. At this time, toner adhesion to the photoconductor can be detected as white spots in all solid images, and photoconductor wear can be detected as image disturbance. The degree of white spots is divided into stages of 10 or more / cm 2 , 4 to 9 / cm 2 , 1 to 3 / cm 2 , and 0 / cm 2 . “No”, “Good”, “Yes”, and “No” were evaluated in the order in which they could be evaluated comprehensively when there was no image, no large image disturbance, and no image disturbance.
<総合評価>
親水性ゾルゲルシリカ粒子を所定の不活性ガスの線速度及び/又は撹拌回転数の条件で乾式表面処理をすることにより、高い疎水率と低い乾燥減量を有し、かつ適度の炭素分量を含んだ乾式表面処理された疎水性ゾルゲルシリカ粉末を得ることができた。高い疎水率と適度の炭素分量を含んだ疎水性ゾルゲルシリカ粉末はトナーと混合した際、分散性が良く、また印刷テストにおいても画像の乱れのないトナー外添剤を得ることができた。
<Comprehensive evaluation>
By subjecting the hydrophilic sol-gel silica particles to a dry surface treatment under the conditions of a predetermined inert gas linear velocity and / or stirring rotation speed, the hydrophilic sol-gel silica particles have a high hydrophobicity and a low loss on drying, and contain an appropriate carbon content. A hydrophobic surface-treated hydrophobic sol-gel silica powder could be obtained. A hydrophobic sol-gel silica powder containing a high hydrophobicity and an appropriate amount of carbon had good dispersibility when mixed with a toner, and it was possible to obtain a toner external additive having no image distortion in a printing test.
本発明の親水性ゾルシリカ粒子の表面処理で得られた疎水性ゾルゲルシリカ粉末は静電荷像現像用トナーの外添剤として、複写機、プリンター、ファクシミリ、製版システムなどのトナーに添加して利用される。 The hydrophobic sol-gel silica powder obtained by the surface treatment of the hydrophilic sol-silica particles of the present invention is used as an external additive for toners for developing electrostatic images and added to toners of copying machines, printers, facsimiles, plate making systems and the like. The
Claims (4)
前記表面処理は前記親水性ゾルゲルシリカ粒子を反応容器に入れた状態で不活性ガス及び前記疎水化剤を前記反応容器内に供給して前記親水性ゾルゲルシリカ粒子を流動させて行う乾式表面処理であって、
前記反応容器内に供給する前記不活性ガスの前記反応容器の横断面積当りの線速度を1〜12m/sの範囲に設定し、前記表面処理時の前記親水性ゾルゲル粒子のかさ密度を前記反応容器内に静置したときの前記親水性ゾルゲルシリカ粒子のかさ密度の0.6〜0.9倍の範囲に設定するとともに、前記反応容器内で表面処理時の親水性ゾルゲルシリカ粒子のかさ密度を150〜300g/Lの範囲に設定することにより表面が疎水化された疎水性ゾルゲルシリカ粉末を得ることを特徴とする親水性ゾルゲルシリカ粒子の表面処理方法。
Si(OR1)4 (1)
(但し、R1は同一又は異なる炭素数1〜4のアルキル基である。) In the method of surface-treating hydrophilic sol-gel silica particles obtained by hydrolyzing and condensing silicon alkoxide represented by the following general formula (1) or a partial hydrolysis-condensation product thereof or a combination thereof with a hydrophobizing agent ,
The surface treatment is a dry surface treatment in which the hydrophilic sol-gel silica particles are flowed by supplying an inert gas and the hydrophobizing agent into the reaction vessel while the hydrophilic sol-gel silica particles are placed in a reaction vessel. There,
A linear velocity per cross-sectional area of the reaction vessel of the inert gas supplied into the reaction vessel is set in a range of 1 to 12 m / s, and a bulk density of the hydrophilic sol-gel particles during the surface treatment is set in the reaction. The bulk density of the hydrophilic sol-gel silica particles during the surface treatment in the reaction container is set in a range of 0.6 to 0.9 times the bulk density of the hydrophilic sol-gel silica particles when left in the container. A surface treatment method for hydrophilic sol-gel silica particles, characterized in that a hydrophobic sol-gel silica powder whose surface has been hydrophobized is obtained by setting the amount to 150 to 300 g / L.
Si (OR 1 ) 4 (1)
(However, R1 is the same or different C1-C4 alkyl group.)
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