JP5568864B2 - Hydrophobic silica fine particles and electrophotographic toner composition - Google Patents
Hydrophobic silica fine particles and electrophotographic toner composition Download PDFInfo
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims description 265
- 239000000377 silicon dioxide Substances 0.000 title claims description 130
- 239000010419 fine particle Substances 0.000 title claims description 116
- 230000002209 hydrophobic effect Effects 0.000 title claims description 56
- 239000000203 mixture Substances 0.000 title claims description 31
- 239000002245 particle Substances 0.000 claims description 69
- 238000000034 method Methods 0.000 claims description 50
- 239000011164 primary particle Substances 0.000 claims description 30
- -1 polysiloxane Polymers 0.000 claims description 27
- 229920001296 polysiloxane Polymers 0.000 claims description 25
- 238000010298 pulverizing process Methods 0.000 claims description 15
- 239000000843 powder Substances 0.000 claims description 14
- 239000012808 vapor phase Substances 0.000 claims description 13
- 238000005259 measurement Methods 0.000 claims description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- 125000000217 alkyl group Chemical group 0.000 claims description 8
- 125000004432 carbon atom Chemical group C* 0.000 claims description 8
- 125000003118 aryl group Chemical group 0.000 claims description 5
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 4
- 239000006185 dispersion Substances 0.000 claims description 3
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 125000004430 oxygen atom Chemical group O* 0.000 claims description 3
- 239000007789 gas Substances 0.000 description 17
- 230000000694 effects Effects 0.000 description 14
- 238000007561 laser diffraction method Methods 0.000 description 13
- 239000012071 phase Substances 0.000 description 12
- 150000003377 silicon compounds Chemical class 0.000 description 10
- 241000519995 Stachys sylvatica Species 0.000 description 9
- 230000007062 hydrolysis Effects 0.000 description 8
- 238000006460 hydrolysis reaction Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000000654 additive Substances 0.000 description 6
- 238000009826 distribution Methods 0.000 description 6
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 6
- 230000000996 additive effect Effects 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 5
- 229910002012 Aerosil® Inorganic materials 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 4
- 238000004381 surface treatment Methods 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 2
- 238000004438 BET method Methods 0.000 description 2
- 150000001343 alkyl silanes Chemical class 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 238000009841 combustion method Methods 0.000 description 2
- 239000002537 cosmetic Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052809 inorganic oxide Inorganic materials 0.000 description 2
- 229910021331 inorganic silicon compound Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000011859 microparticle Substances 0.000 description 2
- 125000001624 naphthyl group Chemical group 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 239000011541 reaction mixture Substances 0.000 description 2
- 239000005049 silicon tetrachloride Substances 0.000 description 2
- 125000001424 substituent group Chemical group 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- 125000005425 toluyl group Chemical group 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 125000005023 xylyl group Chemical group 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- XMSXQFUHVRWGNA-UHFFFAOYSA-N Decamethylcyclopentasiloxane Chemical compound C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1 XMSXQFUHVRWGNA-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 239000006087 Silane Coupling Agent Substances 0.000 description 1
- 229920004482 WACKER® Polymers 0.000 description 1
- 230000002159 abnormal effect 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
- YTJUXOIAXOQWBV-UHFFFAOYSA-N butoxy(trimethyl)silane Chemical compound CCCCO[Si](C)(C)C YTJUXOIAXOQWBV-UHFFFAOYSA-N 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- BUMGIEFFCMBQDG-UHFFFAOYSA-N dichlorosilicon Chemical compound Cl[Si]Cl BUMGIEFFCMBQDG-UHFFFAOYSA-N 0.000 description 1
- BZCJJERBERAQKQ-UHFFFAOYSA-N diethyl(dipropoxy)silane Chemical compound CCCO[Si](CC)(CC)OCCC BZCJJERBERAQKQ-UHFFFAOYSA-N 0.000 description 1
- UCXUKTLCVSGCNR-UHFFFAOYSA-N diethylsilane Chemical compound CC[SiH2]CC UCXUKTLCVSGCNR-UHFFFAOYSA-N 0.000 description 1
- 238000002050 diffraction method Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- SBRXLTRZCJVAPH-UHFFFAOYSA-N ethyl(trimethoxy)silane Chemical compound CC[Si](OC)(OC)OC SBRXLTRZCJVAPH-UHFFFAOYSA-N 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- HTDJPCNNEPUOOQ-UHFFFAOYSA-N hexamethylcyclotrisiloxane Chemical compound C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O1 HTDJPCNNEPUOOQ-UHFFFAOYSA-N 0.000 description 1
- UQEAIHBTYFGYIE-UHFFFAOYSA-N hexamethyldisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)C UQEAIHBTYFGYIE-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- BFXIKLCIZHOAAZ-UHFFFAOYSA-N methyltrimethoxysilane Chemical compound CO[Si](C)(OC)OC BFXIKLCIZHOAAZ-UHFFFAOYSA-N 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- HMMGMWAXVFQUOA-UHFFFAOYSA-N octamethylcyclotetrasiloxane Chemical compound C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1 HMMGMWAXVFQUOA-UHFFFAOYSA-N 0.000 description 1
- CXQXSVUQTKDNFP-UHFFFAOYSA-N octamethyltrisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)O[Si](C)(C)C CXQXSVUQTKDNFP-UHFFFAOYSA-N 0.000 description 1
- 125000000962 organic group Chemical group 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229920005792 styrene-acrylic resin Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000012756 surface treatment agent Substances 0.000 description 1
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 1
- CZDYPVPMEAXLPK-UHFFFAOYSA-N tetramethylsilane Chemical compound C[Si](C)(C)C CZDYPVPMEAXLPK-UHFFFAOYSA-N 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- GYZQBXUDWTVJDF-UHFFFAOYSA-N tributoxy(methyl)silane Chemical compound CCCCO[Si](C)(OCCCC)OCCCC GYZQBXUDWTVJDF-UHFFFAOYSA-N 0.000 description 1
- PPDADIYYMSXQJK-UHFFFAOYSA-N trichlorosilicon Chemical compound Cl[Si](Cl)Cl PPDADIYYMSXQJK-UHFFFAOYSA-N 0.000 description 1
- HQYALQRYBUJWDH-UHFFFAOYSA-N trimethoxy(propyl)silane Chemical compound CCC[Si](OC)(OC)OC HQYALQRYBUJWDH-UHFFFAOYSA-N 0.000 description 1
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Description
本発明は、粉体塗料や電子写真用トナー、化粧料等の粉体系材料において、流動性改善、固結防止、帯電調整等の目的で添加される疎水性シリカ微粒子と、この疎水性シリカ微粒子を用いた電子写真用トナー組成物に関する。 The present invention relates to hydrophobic silica fine particles which are added for the purpose of improving fluidity, preventing caking, adjusting the charge, etc. in powder materials such as powder paints, electrophotographic toners and cosmetics, and the hydrophobic silica fine particles The present invention relates to a toner composition for electrophotography using
微細なシリカ、チタニア、アルミナなどの無機酸化物粉末の表面を有機物によって処理して帯電性や疎水性を改善したいわゆるシリカ微粒子は、複写機、レーザープリンタ、普通紙ファクシミリ等を含む電子写真において、トナー流動性改善剤、或いは帯電性調整剤として広く用いられている。 The so-called silica fine particles, which have improved the chargeability and hydrophobicity by treating the surface of inorganic oxide powders such as fine silica, titania, and alumina with organic substances, are used in electrophotography including copying machines, laser printers, plain paper facsimiles, etc. Widely used as a toner fluidity improver or a charge control agent.
従来、このような用途に用いられる無機酸化物粉末のうち、気相法シリカ（乾式法で製造されたシリカ）は、一次粒子径が小さく、その表面処理による帯電性の制御と疎水化処理で、トナー外添剤として優れた機能を奏することが期待され、最も一般的に使用されている（例えば特許文献１〜３）。 Conventionally, among inorganic oxide powders used in such applications, gas phase method silica (silica produced by a dry method) has a small primary particle size, and it is possible to control chargeability by surface treatment and hydrophobization treatment. Therefore, it is expected to exhibit an excellent function as a toner external additive, and is most commonly used (for example, Patent Documents 1 to 3).
しかし、気相法シリカは一次粒子径が小さいものの、一次粒子径が小さいゆえに凝集し易く、凝集粒子を形成したものが多く、その凝集粒子径は、通常１０μｍから２００μｍ以上にもなる。さらに、表面処理においても粒子径１０μｍ以上の凝集粒子が容易に形成される。 However, although vapor phase silica has a small primary particle size, it is easy to aggregate because the primary particle size is small, and many aggregate particles are formed, and the aggregated particle size is usually 10 μm to 200 μm or more. Furthermore, aggregated particles having a particle diameter of 10 μm or more can be easily formed in the surface treatment.
このような凝集粒子は、トナーへの分散工程において強い摩擦力を受けてほぐされながらトナー間に分散する。トナーの流動化剤として外添される気相法シリカは好ましくは平均一次粒子径１００ｎｍ以下、特に好ましくは５０ｎｍ以下のものが優れた効果を示すが、その中に強い凝集力で形成された大きな凝集体があるとトナーへの分散性が悪く、またトナーから容易に脱離する。その結果として、トナー表面がシリカ微粒子で十分に被覆されず、同じ粒子径を持ち凝集粒子の少ないシリカに比較してトナーへの流動性付与効果が劣る。さらに悪いことには、脱落した凝集粒子が感光体ドラムに付着することによって紙面上で白点となって現れる異常画像の原因になる。 Such agglomerated particles are dispersed between the toners while being loosened by receiving a strong frictional force in the step of dispersing the toners. Gas phase method silica externally added as a fluidizing agent for toner preferably has an average primary particle size of 100 nm or less, particularly preferably 50 nm or less, and exhibits an excellent effect. When there is an aggregate, the dispersibility in the toner is poor and the toner is easily detached from the toner. As a result, the toner surface is not sufficiently covered with silica fine particles, and the fluidity imparting effect to the toner is inferior compared to silica having the same particle size and few aggregated particles. To make matters worse, agglomerated particles that fall off adhere to the photosensitive drum, causing abnormal images that appear as white spots on the paper surface.
なお、特許文献４には、「珪素化合物の燃焼によって得られるシリカ微粒子であって、平均粒子径が０．０５μｍ以上０．１μｍ未満の範囲であり、且つ、ロジン−ラムラー線図で表示した粒度分布の勾配ｎが２以上であり、またレーザ回折・散乱法による測定で１μｍ以上の溶融粒子を含まないことを特徴とするシリカ微粒子。」が記載されているが、このようなシリカ微粒子ではトナー粒子への埋没を抑えることはできるものの、表面処理剤とシリカ微粒子を混合して疎水化などの表面処理を行う過程で凝集粒子が形成されるため、トナーへの十分な分散性および流動性を得ることができない。 Patent Document 4 states that “silica fine particles obtained by combustion of a silicon compound having an average particle diameter in the range of 0.05 μm or more and less than 0.1 μm, and a particle size represented by a rosin-Rammler diagram. Silica fine particles characterized by having a distribution gradient n of 2 or more and not containing molten particles of 1 μm or more as measured by a laser diffraction / scattering method. ” Although the embedding in the particles can be suppressed, aggregated particles are formed in the process of surface treatment such as hydrophobization by mixing the surface treatment agent and silica fine particles, so that the toner has sufficient dispersibility and fluidity. Can't get.
本発明は、トナーへの分散性やトナーの流動性低下の原因となる粗大な凝集粒子を含まず、また、トナーからの脱離を抑制することができ、従って、トナーへの均一分散性と流動性の付与効果に優れ、印刷画像上の白点の発生を抑制できる、トナー外添剤として好適な微細な一次粒子径を有するシリカ微粒子を提供することを目的とする。 The present invention does not include coarse agglomerated particles that cause a decrease in toner dispersibility and toner fluidity, and can prevent detachment from the toner. An object of the present invention is to provide fine silica particles having a fine primary particle size suitable as an external toner additive, which is excellent in fluidity imparting effect and can suppress generation of white spots on a printed image.
本発明はまた、このような高分散性疎水性シリカ微粒子を用いた電子写真用トナー組成物を提供することを目的とする。 Another object of the present invention is to provide an electrophotographic toner composition using such highly dispersible hydrophobic silica fine particles.
本発明者らは、上記課題を解決すべく鋭意検討した結果、気相法シリカ微粒子の平均一次粒子径と、この気相法シリカ微粒子に対して特定の疎水化処理を施してなる疎水性シリカ微粒子の凝集粒子の割合を制御することにより、トナーからの脱離の問題がなく、トナーへの均一分散性と流動性の付与効果に優れ、印刷画像上の白点の発生を抑制できる、トナー外添剤として好適な疎水性シリカ微粒子を得ることができることを見出し、本発明を完成させた。 As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that the average primary particle diameter of the vapor-phase method silica fine particles and the hydrophobic silica obtained by subjecting the vapor-phase method silica fine particles to a specific hydrophobic treatment By controlling the ratio of aggregated particles of fine particles, there is no problem of desorption from the toner, it is excellent in the effect of imparting uniform dispersibility and fluidity to the toner, and the generation of white spots on the printed image can be suppressed. It has been found that hydrophobic silica fine particles suitable as an external additive can be obtained, and the present invention has been completed.
即ち、本発明は以下を要旨とする。 That is, the gist of the present invention is as follows.
［１］ 気相法により得られた平均一次粒子径が２０〜１００ｎｍの親水性シリカ微粒子を下記一般式（Ｉ）で表されるポリシロキサンで疎水化処理し、次いで粉砕後分級により微粉のみを回収してなる疎水性シリカ微粒子であって、強度３０Ｗの超音波を５分間照射して分散させた該疎水性シリカ微粒子のエタノール分散液に対して行ったレーザー回折法による粒子の体積基準粒子径測定で粒子径１．５μｍ以上の凝集粒子の割合が１０％以下であることを特徴とする疎水性シリカ微粒子。 [1] Hydrophobic silica fine particles having an average primary particle diameter of 20 to 100 nm obtained by a gas phase method are hydrophobized with a polysiloxane represented by the following general formula (I), and then only fine powder is obtained by classification after pulverization. Recovered hydrophobic silica fine particles, volume-based particle diameter of particles by laser diffraction method performed on ethanol dispersion liquid of hydrophobic silica fine particles dispersed by irradiating ultrasonic waves with intensity of 30 W for 5 minutes Hydrophobic silica fine particles characterized in that the ratio of aggregated particles having a particle diameter of 1.5 μm or more is 10 % or less .
Ｒ”は、炭素数１〜３のアルキル基、水酸基、または両方のＲ”で一つの酸素原子を表して環状シロキサンを形成する結合を表す。
ｎ、ｍは、それぞれ０以上の整数を表し、ｎとｍの合計は２以上である。
なお、Ｒ’はＲとは異なるものであるが、Ｒ’とＲ”、ＲとＲ”は同一であっても良く、異なるものであっても良い。式中の５個のＲは同一のものをさし、２個のＲ”は互いに同一であっても異なっていても良い。）
R ″ represents an alkyl group having 1 to 3 carbon atoms, a hydroxyl group, or a bond that represents one oxygen atom in both R ″ to form a cyclic siloxane.
n and m each represent an integer of 0 or more, and the sum of n and m is 2 or more.
Although R ′ is different from R, R ′ and R ″ and R and R ″ may be the same or different. In the formula, five Rs are the same, and two R ″ s may be the same or different.)
［２］ ［１］において、親水性シリカ微粒子の平均一次粒子径が５０ｎｍ未満であることを特徴とする疎水性シリカ微粒子。 [2] Hydrophobic silica fine particles according to [1], wherein the hydrophilic silica fine particles have an average primary particle size of less than 50 nm.
［３］ ［２］又は［２］において、疎水率が９７％以上であることを特徴とする疎水性シリカ微粒子。 [3] Hydrophobic silica fine particles according to [2] or [2], wherein the hydrophobic rate is 97% or more.
［４］ ［１］ないし［３］のいずれかにおいて、トナー外添用シリカ微粒子であることを特徴とする疎水性シリカ微粒子。 [4] The hydrophobic silica fine particles according to any one of [1] to [3], which are silica fine particles for external toner addition.
［５］ ［１］ないし［４］のいずれかに記載の疎水性シリカ微粒子を外添したことを特徴とする電子写真用トナー組成物。 [5] A toner composition for electrophotography, wherein the hydrophobic silica fine particles according to any one of [1] to [4] are externally added.
本発明の疎水性シリカ微粒子は、気相法により得られた、平均一次粒子径が２０〜１００ｎｍと非常に微細な一次粒子よりなる親水性シリカ微粒子を前記一般式（Ｉ）で表されるポリシロキサン（以下「ポリシロキサン（Ｉ）」と称す場合がある。）で疎水化処理し、次いで粉砕後分級により微粉のみを回収してなり、しかも、レーザー回折法による粒子の体積基準粒子径測定において、粒子径１．５μｍ以上の凝集粒子の割合が１０％以下と、粗大な凝集粒子を殆ど含まないため、トナー等への均一分散性に優れ、シリカ微粒子本来の流動性改善効果を有効に発揮することができ、また、トナーからの脱落の問題もないため、印刷画像上の白点の発生を抑制することができる。
このような本発明の疎水性シリカ微粒子は、粉体塗料や電子写真用トナー、化粧料等の粉体材料系において、流動性改善、固結防止、帯電調整等の目的で添加されるシリカ微粒子として工業的に極めて有用である。
Hydrophobic silica fine particles of the present invention are hydrophilic silica fine particles obtained by a vapor phase method and having an average primary particle diameter of 20 to 100 nm and consisting of very fine primary particles. Hydrophobic treatment with siloxane (hereinafter sometimes referred to as “polysiloxane (I)”), and then only the fine powder is recovered by classification after pulverization . Moreover, in volume-based particle size measurement by laser diffraction method The ratio of aggregated particles with a particle size of 1.5 μm or more is 10 % or less, and almost no coarse aggregated particles are contained. Therefore, it is excellent in uniform dispersibility in toner, etc., and effectively exhibits the original fluidity improvement effect of silica fine particles. In addition, since there is no problem of falling off from the toner, the generation of white spots on the printed image can be suppressed.
Such hydrophobic silica fine particles of the present invention are silica fine particles that are added for the purpose of improving fluidity, preventing caking, and adjusting the charge in powder material systems such as powder paints, electrophotographic toners, and cosmetics. As industrially very useful.
本発明に係る親水性シリカ微粒子の平均一次粒子径は５０ｎｍ以下であることが好ましい（請求項２）。 The average primary particle diameter of the hydrophilic silica fine particles according to the present invention is preferably 50 nm or less (claim 2).
また、本発明の疎水性シリカ微粒子の疎水率は９７％以上であることが好ましい（請求項３）。 Further, the hydrophobic rate of the hydrophobic silica fine particles of the present invention is preferably 97% or more (claim 3).
また、本発明の疎水性シリカ微粒子はトナー外添用シリカ微粒子として有効である（請求項４）。 Further, the hydrophobic silica fine particles of the present invention are effective as silica fine particles for external addition of toner (claim 4).
本発明の電子写真用トナー組成物は、このような本発明の疎水性シリカ微粒子を外添したものであり、流動性に優れ、白点画像等の画像欠陥を生じにくい、高特性電子写真用トナー組成物である。 The toner composition for electrophotography of the present invention is an external addition of the hydrophobic silica fine particles of the present invention, and has excellent fluidity and is unlikely to cause image defects such as white spot images. Toner composition.
以下に本発明の疎水性シリカ微粒子及び電子写真用トナー組成物の実施の形態を詳細に説明する。 Hereinafter, embodiments of the hydrophobic silica fine particles and the electrophotographic toner composition of the present invention will be described in detail.
［疎水性シリカ微粒子］
本発明の疎水性シリカ微粒子は、気相法により得られた平均一次粒子径が２０〜１００ｎｍの親水性シリカ微粒子をポリシロキサン（Ｉ）で疎水化処理し、次いで粉砕後分級により微粉のみを回収してなる疎水性シリカ微粒子であって、レーザー回折法による粒子の体積基準粒子径測定で粒子径１．５μｍ以上の凝集粒子の割合が１０％以下であることを特徴とする。
[Hydrophobic silica fine particles]
Hydrophobic silica fine particles of the present invention are obtained by hydrophobizing hydrophilic silica fine particles having an average primary particle diameter of 20 to 100 nm obtained by a gas phase method with polysiloxane (I), and then collecting only fine powder by classification after pulverization. The ratio of aggregated particles having a particle diameter of 1.5 μm or more is 10 % or less as measured by measuring the volume-based particle diameter of the particles using a laser diffraction method.
＜気相法による親水性シリカ微粒子＞
本発明に係る気相法による親水性シリカ微粒子は、乾式法シリカとも呼ばれ、その製法は珪素化合物の火炎加水分解、火炎中燃焼法による酸化、あるいはこれらの反応の併用による方法で製造されたものであれば良く、特に制限されない。中でも火炎加水分解法により製造された気相法シリカが好適に用いられる。市販されている製品としては、日本アエロジル社製あるいはエボニックデグサ社製の「アエロジル」、キャボット社製の「キャボジル」、ワッカー社製の「ＨＤＫ」、トクヤマ社製の「レオロシール」等がある。
<Hydrophilic silica fine particles by vapor phase method>
The hydrophilic silica fine particles by the vapor phase method according to the present invention are also called dry silica, and the production method thereof is manufactured by flame hydrolysis of a silicon compound, oxidation by a flame combustion method, or a combination of these reactions. There is no particular limitation as long as it is a thing. Among these, gas phase method silica produced by a flame hydrolysis method is preferably used. Examples of the commercially available products include “Aerosil” manufactured by Nippon Aerosil Co., Ltd. or Evonik Degussa, “Cabosil” manufactured by Cabot, “HDK” manufactured by Wacker, “Reolosil” manufactured by Tokuyama, and the like.
火炎加水分解法による気相法シリカの製造方法は、例えば、四塩化ケイ素等の原料珪素化合物のガスを不活性ガスと共に燃焼バーナーの混合室に導入し、水素及び空気と混合して所定比率の混合ガスとし、この混合ガスを反応室で１０００〜３０００℃の温度で燃焼させて生成させ、冷却後、生成したシリカをフィルターで捕集する方法である。火炎加水分解法についてのより詳細な製造方法としては、ドイツ特許第９７４，７９３号、同第９７４，９７４号及び同第９０９，３３９号の各公報に記載の方法を参照することができる。 The method for producing vapor phase silica by the flame hydrolysis method is, for example, introducing a raw material silicon compound gas such as silicon tetrachloride together with an inert gas into a mixing chamber of a combustion burner and mixing it with hydrogen and air at a predetermined ratio. In this method, the mixed gas is produced by burning the mixed gas in a reaction chamber at a temperature of 1000 to 3000 ° C., and after cooling, the produced silica is collected by a filter. As a more detailed production method for the flame hydrolysis method, methods described in German Patent Nos. 974,793, 974,974, and 909,339 can be referred to.
火炎中燃焼法は、アルキルシラン、アルコキシシラン及び／又はその部分加水分解縮合物を火炎中で燃焼分解する方法である。すなわち、アルキルシラン、アルコキシシラン及び／又はその部分加水分解縮合物を加熱蒸発させて窒素ガスなどの不活性ガスに伴流させるか、又は噴霧させて、酸水素火炎などの火炎中に導入し、この火炎中で燃焼分解させる。 The combustion method in flame is a method in which alkylsilane, alkoxysilane and / or a partial hydrolysis condensate thereof are burned and decomposed in a flame. That is, the alkylsilane, alkoxysilane and / or the partial hydrolysis condensate thereof is evaporated by heating and entrained in an inert gas such as nitrogen gas or sprayed and introduced into a flame such as an oxyhydrogen flame, It is burned and decomposed in this flame.
気相法シリカの原料として用いられる珪素化合物としては、各種の無機珪素化合物、有機珪素化合物が挙げられる。例えば、四塩化珪素、三塩化珪素、二塩化珪素などの無機珪素化合物、ヘキサメチルシクロトリシロキサン、オクタメチルシクロテトラシロキサン、デカメチルシクロペンタシロキサン、ヘキサメチルジシロキサン、オクタメチルトリシロキサンなどのシロキサン、メチルトリメトキシシラン、テトラメトキシシラン、エチルトリメトキシシラン、ｎ−プロピルトリメトキシシラン、メチルトリブトキシシラン、ジエチルジプロポキシシラン、トリメチルブトキシシランなどのアルコキシシラン、テトラメチルシラン、ジエチルシラン、ポリシロキサン（Ｉ）、或いはこれらのオリゴマー、ポリマーなどの有機珪素化合物が挙げられる。 Examples of the silicon compound used as a raw material for the vapor phase method silica include various inorganic silicon compounds and organic silicon compounds. For example, inorganic silicon compounds such as silicon tetrachloride, silicon trichloride, silicon dichloride, siloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, octamethyltrisiloxane, Alkoxysilanes such as methyltrimethoxysilane, tetramethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, methyltributoxysilane, diethyldipropoxysilane, trimethylbutoxysilane, tetramethylsilane, diethylsilane, polysiloxane (I Or organic silicon compounds such as oligomers and polymers thereof.
このような珪素化合物の火炎中での加水分解及び燃焼分解は、この珪素化合物を必要に応じて蒸留などで精製した後、加熱蒸発させてこれを窒素ガスなどの不活性ガスに伴流させる気流伴送法や、珪素化合物を霧化させて火炎中に供給する方法で、酸水素火炎などの火炎中に導入し、この火炎中で反応させて行えばよいが、この際には、水素ガス、メタンガスなどのような可燃性ガスを助燃ガスとしてもよい。この助燃ガスとしては残渣の残らないものであればいずれも使用することができ、特に制限はない。 Hydrolysis and combustion decomposition of such a silicon compound in a flame is carried out by purifying the silicon compound by distillation or the like, if necessary, and then evaporating it by heating to wake it with an inert gas such as nitrogen gas. In the entrainment method or the method of atomizing the silicon compound and supplying it into the flame, it may be introduced into a flame such as an oxyhydrogen flame and reacted in this flame. Further, a flammable gas such as methane gas may be used as the auxiliary combustion gas. Any auxiliary combustion gas can be used as long as no residue remains, and there is no particular limitation.
珪素化合物の加水分解又は燃焼分解で生成したシリカは、バグフィルター、サイクロンなど公知の方法で捕集される。 Silica produced by hydrolysis or combustion decomposition of a silicon compound is collected by a known method such as a bag filter or a cyclone.
このような気相法シリカは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。 Such gas phase method silica may be used alone or in combination of two or more.
＜平均一次粒子径＞
本発明において、気相法により得られ、疎水化処理に供される親水性シリカ微粒子は、平均一次粒子径が２０〜１００ｎｍであることを特徴とする。親水性シリカ微粒子の平均一次粒子径が１００ｎｍより大きいと、得られる疎水性シリカ微粒子のトナーへの分散性が悪く、流動性向上効果に劣るものとなる。平均一次粒子径が２０ｎｍより小さい気相法シリカ微粒子は凝集し易く、凝集粒子の割合が多くなるため好ましくない。
<Average primary particle size>
In the present invention, hydrophilic silica fine particles obtained by a gas phase method and subjected to a hydrophobization treatment have an average primary particle diameter of 20 to 100 nm. When the average primary particle diameter of the hydrophilic silica fine particles is larger than 100 nm, the dispersibility of the resulting hydrophobic silica fine particles in the toner is poor and the effect of improving the fluidity is inferior. Vapor phase silica fine particles having an average primary particle size of less than 20 nm are not preferred because they tend to aggregate and the proportion of aggregated particles increases.
特に、流動性付与効果の面から、親水性シリカ微粒子の平均一次粒子径は５０ｎｍ以下、例えば４５ｎｍ以下であることが好ましい。
特に、凝集粒子割合の面から、親水性シリカ微粒子の平均一次粒子径は３０ｎｍ以上であることが好ましい。
In particular, from the viewpoint of fluidity imparting effect, the average primary particle diameter of the hydrophilic silica fine particles is preferably 50 nm or less, for example, 45 nm or less.
In particular, the average primary particle diameter of the hydrophilic silica fine particles is preferably 30 nm or more from the aspect of the aggregate particle ratio.
なお、本発明に係る親水性シリカ微粒子の平均一次粒子径は、後述の実施例の項に示されるように、透過型電子顕微鏡観察により求められる。 In addition, the average primary particle diameter of the hydrophilic silica fine particles according to the present invention is determined by observation with a transmission electron microscope, as shown in the Examples section described later.
＜ＢＥＴ比表面積＞
気相法により得られる親水性シリカ微粒子のＢＥＴ比表面積は主に平均一次粒子径に依存するが、本発明の実施において疎水化処理に供される親水性シリカ微粒子のＢＥＴ比表面積は１０〜１２０ｍ２／ｇが好ましく、さらには１５〜９０ｍ２／ｇが好ましい。親水性シリカ微粒子のＢＥＴ比表面積が小さ過ぎると、得られる疎水性シリカ微粒子のトナーへの分散性が悪く、流動性向上効果に劣るものとなる。ＢＥＴ比表面積が大き過ぎる気相法シリカ微粒子は粉砕後に凝集し易く、また凝集力が強いため好ましくない。
<BET specific surface area>
The BET specific surface area of the hydrophilic silica fine particles obtained by the gas phase method mainly depends on the average primary particle diameter, but the BET specific surface area of the hydrophilic silica fine particles subjected to the hydrophobization treatment in the practice of the present invention is 10 to 120 m. 2 / g is preferable, and 15 to 90 m 2 / g is more preferable. When the BET specific surface area of the hydrophilic silica fine particles is too small, the dispersibility of the obtained hydrophobic silica fine particles in the toner is poor and the effect of improving the fluidity is inferior. Vapor-phase silica fine particles having an excessively large BET specific surface area are not preferred because they tend to aggregate after pulverization and have a strong cohesive force.
特に、流動性付与効果の面から、親水性シリカ微粒子のＢＥＴ比表面積は２５〜９０ｍ２／ｇであることが好ましい。 In particular, from the viewpoint of fluidity imparting effect, the BET specific surface area of the hydrophilic silica fine particles is preferably 25 to 90 m 2 / g.
なお、本発明に係る親水性シリカ微粒子のＢＥＴ比表面積は、後述の実施例の項に示されるように、ＢＥＴ法により求められる。 The BET specific surface area of the hydrophilic silica fine particles according to the present invention is determined by the BET method as shown in the Examples section described later.
＜疎水化処理＞
本発明の疎水性シリカ微粒子は、上述のような平均一次粒子径を有する気相法による親水性シリカ微粒子を下記一般式（Ｉ）で表されるポリシロキサンで疎水化処理してなるものである。
<Hydrophobic treatment>
The hydrophobic silica fine particles of the present invention are obtained by hydrophobizing hydrophilic silica fine particles by the gas phase method having the average primary particle diameter as described above with a polysiloxane represented by the following general formula (I). .
Ｒ”は、炭素数１〜３のアルキル基、水酸基、または両方のＲ”で一つの酸素原子を表して環状シロキサンを形成する結合を表す。
ｎ、ｍは、それぞれ０以上の整数を表し、ｎとｍの合計は２以上である。
なお、Ｒ’はＲとは異なるものであるが、Ｒ’とＲ”、ＲとＲ”は同一であっても良く、異なるものであっても良い。式中の５個のＲは同一のものをさし、２個のＲ”は互いに同一であっても異なっていても良い。）
R ″ represents an alkyl group having 1 to 3 carbon atoms, a hydroxyl group, or a bond that represents one oxygen atom in both R ″ to form a cyclic siloxane.
n and m each represent an integer of 0 or more, and the sum of n and m is 2 or more.
Although R ′ is different from R, R ′ and R ″ and R and R ″ may be the same or different. In the formula, five Rs are the same, and two R ″ s may be the same or different.)
シリカ微粒子の疎水化処理の方法としては、例えば、特許第３２２９１７４号公報に記載されるような、シランカップリング剤とシリコーンオイルを用いる方法、特公昭６１−５０８８２号公報に記載されるようなオルガノハロゲンシランを用いる方法、特公昭５７−２６４１号公報に記載されるようなオルガノポリシロキサンを用いる方法、特開昭６２−１７１９１３号公報に記載されるようなシロキサンオリゴマーを用いる方法などが挙げられる。 As a method for hydrophobizing silica fine particles, for example, a method using a silane coupling agent and silicone oil as described in Japanese Patent No. 3229174, or an organo as described in Japanese Patent Publication No. 61-50882. Examples thereof include a method using a halogen silane, a method using an organopolysiloxane as described in JP-B-57-2641, and a method using a siloxane oligomer as described in JP-A-62-171913.
これらのうち、特に、本発明では、疎水性が高くトナーへの流動性の付与効果が高く、さらには物理吸着したポリシロキサン（Ｉ）によって感光体ドラム表面のクリーニング効果をも有する表面処理方法である、ポリシロキサン（Ｉ）による方法を採用する。 Among these, in particular, the present invention is a surface treatment method that has high hydrophobicity and high fluidity imparting effect on the toner, and also has a cleaning effect on the surface of the photosensitive drum by the physically adsorbed polysiloxane (I). A certain method based on polysiloxane (I) is employed.
本発明で用いるポリシロキサン（Ｉ）において、Ｒ，Ｒ’のアリール基としては、フェニル基、トルイル基、キシリル基、ナフチル基等が挙げられ、これらのうち、好ましくはフェニル基である。 In the polysiloxane (I) used in the present invention, examples of the aryl group of R and R ′ include a phenyl group, a toluyl group, a xylyl group, and a naphthyl group, and among these, a phenyl group is preferable.
Ｒ，Ｒ’，Ｒ”の炭素数１〜３のアルキル基、Ｒ，Ｒ’のアリール基は、１又は２以上の置換基を有していても良く、この場合、その置換基としては、炭素数１〜４のアルキル基、フェニル基、トルイル基、キシリル基、ナフチル基等が挙げられる。 The alkyl group having 1 to 3 carbon atoms of R, R ′, and R ″ and the aryl group of R and R ′ may have one or two or more substituents. In this case, as the substituents, Examples thereof include an alkyl group having 1 to 4 carbon atoms, a phenyl group, a toluyl group, a xylyl group, and a naphthyl group.
Ｒとしては、特にメチル基、エチル基、プロピル基が好ましい。
また、Ｒ’としては、特に水素原子、メチル基、フェニル基が好ましい。
また、Ｒ”としては、特にメチル基、水酸基が好ましい。
R is particularly preferably a methyl group, an ethyl group, or a propyl group.
R ′ is particularly preferably a hydrogen atom, a methyl group, or a phenyl group.
R ″ is particularly preferably a methyl group or a hydroxyl group.
ｎ，ｍはそれぞれ０以上の整数を表し、ｎ＋ｍ≧２である。
ｎは特に０〜８００であることが好ましく、ｍは特に０〜１０００であることが好ましく、ｎとｍは合計で１０〜１０００であることが好ましい。
n and m each represent an integer of 0 or more, and n + m ≧ 2.
n is particularly preferably 0 to 800, m is particularly preferably 0 to 1000, and n and m are preferably 10 to 1000 in total.
また、ポリシロキサン（Ｉ）の分子量は特に１０００〜１０００００であることが好ましい。 The molecular weight of polysiloxane (I) is particularly preferably 1000 to 100,000.
本発明において、ポリシロキサン（Ｉ）は１種を単独で用いても良く、２種以上を任意の比率で混合して用いても良い。 In this invention, polysiloxane (I) may be used individually by 1 type, and may mix and use 2 or more types by arbitrary ratios.
このようなポリシロキサン（Ｉ）による疎水化処理は、具体的には次のようにして実施される。 Specifically, the hydrophobization treatment with such polysiloxane (I) is performed as follows.
平均一次粒子径２０〜１００ｎｍの気相法シリカ粉末１００重量部を反応容器に入れ、窒素雰囲気下、ポリシロキサン（Ｉ）０．５〜３０重量部をスプレーする。この反応混合物を２２０〜３８０℃にて０．５〜３時間程度、窒素気流下で攪拌することにより、ポリシロキサンとシリカ表面を反応させる。これを冷却することにより、疎水性シリカ微粒子を得る。 100 parts by weight of gas phase method silica powder having an average primary particle size of 20 to 100 nm is placed in a reaction vessel, and 0.5 to 30 parts by weight of polysiloxane (I) is sprayed in a nitrogen atmosphere. By stirring this reaction mixture at 220 to 380 ° C. for about 0.5 to 3 hours under a nitrogen stream, the polysiloxane and the silica surface are reacted. By cooling this, hydrophobic silica fine particles are obtained.
このような疎水化処理において、親水性シリカ微粒子１００重量部の疎水化処理に用いるポリシロキサン（Ｉ）の量は、疎水化処理に供する親水性シリカ微粒子のＢＥＴ比表面積に対して、次のような式で算出される量であることが好ましい。
ポリシロキサン（Ｉ）（重量部）
＝親水性シリカ微粒子のＢＥＴ比表面積（ｍ２／ｇ）／Ｈ
上記計算式において、Ｈは２〜２０、特に８であることが好ましい。
上記範囲よりもポリシロキサン（Ｉ）の使用量が多いと疎水化処理後の生成物に凝集物が多く発生し、少ないとトナー外添剤として十分な疎水性が付与されない。
In such a hydrophobic treatment, the amount of polysiloxane (I) used for the hydrophobic treatment of 100 parts by weight of the hydrophilic silica fine particles is as follows with respect to the BET specific surface area of the hydrophilic silica fine particles to be subjected to the hydrophobic treatment. It is preferable that the amount be calculated by a simple equation.
Polysiloxane (I) (parts by weight)
= BET specific surface area of hydrophilic silica fine particles (m 2 / g) / H
In the above formula, H is preferably 2 to 20, particularly 8.
When the amount of polysiloxane (I) used is larger than the above range, a large amount of aggregates are generated in the product after the hydrophobization treatment, and when it is less, sufficient hydrophobicity as a toner external additive is not imparted.
なお、ポリシロキサン（Ｉ）は単独で親水性シリカ微粒子に対してスプレーしても良いが、高粘度の場合にはヘキサンやトルエンなどの揮発性有機溶媒に１〜９０重量％程度の濃度に溶解してスプレーしても良い。 Polysiloxane (I) may be sprayed alone on hydrophilic silica fine particles, but in the case of high viscosity, it dissolves in a concentration of about 1 to 90% by weight in a volatile organic solvent such as hexane or toluene. And spray it.
本発明では、このような疎水化処理により、後述の実施例の項に記載される方法で測定される疎水率が９７％以上、特に９９％以上のシリカ微粒子とすることが好ましい。 In the present invention, it is preferable to obtain silica fine particles having a hydrophobicity of 97% or more, particularly 99% or more, measured by the method described in the Examples section below, by such a hydrophobizing treatment.
＜凝集粒子の割合＞
本発明の疎水性シリカ微粒子は、レーザー回折法による粒子の体積基準粒子径測定で粒子径１．５μｍ以上の凝集粒子の割合（以下、この割合を「レーザー回折法凝集粒子割合」と称す場合がある。）が１０％以下であることを特徴とする。即ち、例えば、図１に示すレーザー回折法による粒子の体積基準粒子径測定における回折チャートにおいて、１．５μｍ以上の凝集粒子の分布割合が１０％以下であることを特徴とする。
このレーザー回折法凝集粒子割合が１２％以上では、大きな凝集粒子が多いことにより、トナーへの均一分散性に劣り、良好な流動性、白点の少ない良好な印刷画質を得ることができない。
<Ratio of aggregated particles>
The hydrophobic silica fine particles of the present invention have a proportion of agglomerated particles having a particle diameter of 1.5 μm or more as measured by a volume diffracted particle size by a laser diffraction method (hereinafter, this proportion may be referred to as a “laser diffraction method agglomerated particle proportion”). Is) 10 % or less . That is, for example, in the diffraction chart for measuring the volume-based particle diameter of particles by the laser diffraction method shown in FIG. 1, the distribution ratio of aggregated particles of 1.5 μm or more is 10 % or less .
When the ratio of the aggregated particles by laser diffraction method is 12% or more, there are many large aggregated particles, so that the uniform dispersibility in the toner is inferior, and good fluidity and good print image quality with few white spots cannot be obtained.
レーザー回折法凝集粒子割合は小さい程好ましく、特に５％以下であることが好ましい。 Preferably as laser diffractometry agglomerated particle fraction is small, it is preferably 5% or less, especially.
なお、このレーザー回折法凝集粒子割合は後述の実施例の項に示されるように、堀場製作所社製レーザー回折式粒度分布計「ＬＡ９２０」を用いて、シリカ微粒子のエタノール分散液に対して測定することにより求められる。 The ratio of the aggregated particles by laser diffraction method is measured with respect to an ethanol dispersion of silica fine particles using a laser diffraction particle size distribution analyzer “LA920” manufactured by Horiba, Ltd. as shown in the Examples section below. Is required.
上述のレーザー回折法凝集粒子割合の本発明の疎水性シリカ微粒子は、前述の気相法により製造された親水性シリカ微粒子をポリシロキサン（Ｉ）を用いて疎水化処理したものを原料に用い、ピンミル、ジェットミル等の粉砕機で粉砕した後、気流式分級法などにより分級して微粉のみを回収し、この粉砕、分級を必要に応じて繰り返すことにより得ることができる。
この際、分級で分離された粗粒分は、粉砕工程へ循環させることが工程の効率において好ましい。
なお、分級と粉砕が同時に行われる機構を備えた粉砕機や、分級工程が粉砕機に組み込まれた粉砕機を用いる場合、分級が不十分であると判断された場合には、別途分級機を設置して、より高度な分級工程を行うようにすることが好ましい。
The hydrophobic silica fine particles of the present invention having the above-mentioned laser diffraction method aggregated particle ratio are obtained by using, as a raw material, hydrophobized silica fine particles produced by the gas phase method described above using polysiloxane (I), After being pulverized by a pulverizer such as a pin mill or a jet mill, it is classified by an airflow classification method or the like to collect only fine powder, and this pulverization and classification can be repeated as necessary.
At this time, it is preferable in terms of the efficiency of the process that the coarse particles separated by classification are circulated to the pulverization process.
In addition, when using a pulverizer equipped with a mechanism for performing classification and pulverization at the same time, or using a pulverizer in which the classification process is incorporated into the pulverizer, if it is determined that the classification is insufficient, a separate classifier is used. It is preferable to install and perform a more advanced classification process.
前述の疎水化処理によりシリカ微粒子の凝集が起こることから、疎水化処理はこの粉砕・分級処理に先立ち行い、疎水化処理後に上述の粉砕・分級処理を行う。 Since the silica particles are aggregated by the hydrophobization treatment, the hydrophobization treatment is performed prior to the pulverization / classification treatment, and the pulverization / classification treatment is performed after the hydrophobization treatment.
［電子写真用トナー組成物］
本発明の電子写真用トナー組成物は、上述の本発明の疎水性シリカ微粒子を外添したものであり、そ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 composition for electrophotography]
The toner composition for electrophotography of the present invention is obtained by externally adding the above-described hydrophobic silica fine particles of the present invention. There is no particular limitation on the composition and the production method thereof, and a known composition and method should be adopted. Can do.
本発明の電子写真用トナー組成物の製造に当り、本発明の疎水性シリカ微粒子の添加量は、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、特に制限されないが、電子写真用トナー組成物中に、本発明の疎水性シリカ微粒子が０．１〜６．０重量％含有されていることが好ましい。電子写真用トナー組成物中の本発明の疎水性シリカ微粒子の含有量が０．１重量％未満では、このシリカ微粒子を添加したことによる流動性の改善効果や帯電性の安定効果が十分に得られない。また、シリカ微粒子の含有量が６．０重量％を超えるとトナー表面から脱離してシリカ微粒子単独で行動するものが多くなり、画像やクリーニング性に問題が生じてくる。 In the production of the electrophotographic toner composition of the present invention, the amount of the hydrophobic silica fine particles of the present invention added is not particularly limited as long as the desired effect of improving the properties can be obtained. The toner composition preferably contains 0.1 to 6.0% by weight of the hydrophobic silica fine particles of the present invention. When the content of the hydrophobic silica fine particles of the present invention in the electrophotographic toner composition is less than 0.1% by weight, the effect of improving fluidity and the effect of stabilizing the charging property are sufficiently obtained by adding the silica fine particles. I can't. On the other hand, when the content of the silica fine particles exceeds 6.0% by weight, many particles are detached from the surface of the toner and act by the silica fine particles alone, resulting in problems in image and cleaning properties.
電子写真用トナー組成物中の本発明の疎水性シリカ微粒子の含有量Ｓ（重量％）はトナー粒子の平均粒子径に依存し、例えば近年一般に使用されている平均粒子径が５〜９μｍのトナーにおいては、疎水性シリカ微粒子の製造に用いた親水性シリカ微粒子の平均一次粒子径ｒ（ｎｍ）に対して、ｒ／４０≦Ｓ≦ｒ／７の範囲であることが好ましく、特にＳ＝ｒ／２０であることが好ましい。 The content S (% by weight) of the hydrophobic silica fine particles of the present invention in the toner composition for electrophotography depends on the average particle diameter of the toner particles. For example, a toner having an average particle diameter of 5 to 9 μm that has been generally used in recent years. Is preferably in the range of r / 40 ≦ S ≦ r / 7 with respect to the average primary particle diameter r (nm) of the hydrophilic silica fine particles used for the production of the hydrophobic silica fine particles, and in particular, S = r / 20 is preferable.
トナーには一般に熱可塑性樹脂の他、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。本発明では、上記シリカ微粒子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１成分系トナー、２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。 In general, the toner contains a small amount of a pigment, a charge control agent, and other external additives in addition to the thermoplastic resin. In the present invention, as long as the silica fine particles are blended, the other components may be the same as those in the past, and may be either a magnetic or nonmagnetic 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.
なお、本発明の電子写真用トナー組成物の製造に当り、外添剤としての本発明の疎水性シリカ微粒子は、単独で使用されるに限られず、目的に応じて、他の金属酸化物微粒子と併用しても良い。例えば、上記シリカ微粒子と、他の表面改質された乾式シリカ微粒子や表面改質された乾式酸化チタン微粒子や表面改質された湿式酸化チタン微粒子等を併用することができる。 In the production of the electrophotographic toner composition of the present invention, the hydrophobic silica fine particles of the present invention as an external additive are not limited to being used alone, but may be other metal oxide fine particles depending on the purpose. You may use together. For example, the silica fine particles can be used in combination with other surface-modified dry silica fine particles, surface-modified dry titanium oxide fine particles, surface-modified wet titanium oxide fine particles, and the like.
以下に実施例及び比較例を挙げて、本発明をより具体的に説明する。 Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
なお、以下の実施例及び比較例におけるシリカ微粒子及びトナー組成物の評価方法は次の通りである。 In addition, the evaluation method of the silica fine particles and the toner composition in the following examples and comparative examples is as follows.
［シリカ微粒子の評価］
＜平均一次粒子径＞
透過型電子顕微鏡像上で、シリカ微粒子サンプルから無作為の粒子２５００個以上の粒子径を測定し、個数平均により平均一次粒子径を求めた。
[Evaluation of silica fine particles]
<Average primary particle size>
On a transmission electron microscope image, the particle diameter of 2500 or more random particles was measured from the silica fine particle sample, and the average primary particle diameter was determined by number average.
＜ＢＥＴ比表面積＞
ＢＥＴ法により測定した。
<BET specific surface area>
It was measured by the BET method.
＜レーザー回折法凝集粒子割合＞
凝集粒子割合の測定には、堀場製作所製レーザー回折式粒度分布計「ＬＡ９２０」を用いた。測定溶媒にはエタノールを用いた。疎水性シリカ微粒子サンプル約０．２ｇを用い、装置所定の方法に従って測定を行った。測定前処理として、強度３０Ｗの超音波を５分間照射してサンプルを分散した。図１に示すような体積平均粒径の測定結果から、粒子径１．５μｍ以上の凝集粒子の割合を求めた。
<Laser diffraction method aggregated particle ratio>
A laser diffraction particle size distribution analyzer “LA920” manufactured by HORIBA, Ltd. was used for the measurement of the aggregated particle ratio. Ethanol was used as a measurement solvent. Using about 0.2 g of a hydrophobic silica fine particle sample, the measurement was performed according to a method prescribed by the apparatus. As a measurement pretreatment, the sample was dispersed by irradiating with ultrasonic waves of intensity 30 W for 5 minutes. From the measurement result of the volume average particle diameter as shown in FIG. 1, the ratio of aggregated particles having a particle diameter of 1.5 μm or more was determined.
＜疎水率＞
疎水性シリカ微粒子サンプル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１０分間振盪した。振盪後、１０分間静置した。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、その波長５００ｎｍの光の透過率を疎水率とした。
<Hydrophobic rate>
A 1 g sample of hydrophobic silica fine particles was weighed into a 200 mL separatory funnel, 100 mL of pure water was added thereto, the stopper was plugged, and the mixture was shaken with a tumbler mixer for 10 minutes. After shaking, it was allowed to stand for 10 minutes. 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 the transmittance of light having a wavelength of 500 nm is determined as the hydrophobicity. It was.
［トナー組成物の評価］
＜安息角＞
トナー組成物の安息角は、パウダーテスターＰＴ−Ｓ（ホソカワミクロン社製）を用いて測定した。約２０ｇのトナーサンプルを目開き３５５μｍの篩に載せ、振動により落下するトナーサンプルを漏斗を通して、この漏斗先端から約６．５ｃｍ下方に設置した直径８ｃｍの円形テーブルに堆積させた。円錐状に形成された堆積トナーサンプルの、水平面に対する側面の角度を安息角とした。
測定されたトナー組成物の安息角が小さいほど、シリカ微粒子中の凝集粒子が小さく、流動性に優れる。
本発明においては、安息角４１°以下で合格とし、３９°以下を良好とした。
[Evaluation of Toner Composition]
<Repose angle>
The angle of repose of the toner composition was measured using a powder tester PT-S (manufactured by Hosokawa Micron). About 20 g of the toner sample was placed on a sieve having an opening of 355 μm, and the toner sample dropped by vibration was deposited through a funnel on a circular table having a diameter of 8 cm installed about 6.5 cm below the tip of the funnel. The angle of the side surface of the deposited toner sample formed in a conical shape with respect to the horizontal plane was defined as an angle of repose.
The smaller the angle of repose of the measured toner composition, the smaller the aggregated particles in the silica fine particles and the better the fluidity.
In the present invention, the repose angle is 41 ° or less, and the acceptance is 39 ° or less.
＜白点画像の評価方法＞
トナー組成物を市販の複写機に充填し、Ａ４コピー紙１０００枚の連続通紙で１枚あたり３ｃｍ×３ｃｍのベタ画像１０個を印刷し、１０００枚目のの画像上に見られる、直径０．２ｍｍ以上の白点の個数をカウントし、画像あたり平均個数を計算した。
本発明においては、この白点画像の平均個数が２以下で合格とした。
<Evaluation method of white spot image>
The toner composition is filled in a commercially available copying machine, 10 solid images of 3 cm × 3 cm per sheet are printed on 1000 sheets of A4 copy paper, and the diameter is 0 on the 1000th image. The number of white spots of 2 mm or more was counted and the average number per image was calculated.
In the present invention, the average number of white spot images is 2 or less, which is acceptable.
［実施例１］
気相法シリカ微粒子として日本アエロジル（株）製商品名「ＡＥＲＯＳＩＬ（登録商標）９０」（ＢＥＴ比表面積９０ｍ２／ｇ、平均一次粒子径２０ｎｍ）を用い、この気相法シリカ微粒子を、以下の条件で疎水化処理した後、以下の条件で粉砕、分級することにより、表１に示す平均一次粒子径及びレーザー回折法凝集粒子割合のシリカ微粒子を得た。
[Example 1]
The product name “AEROSIL (registered trademark) 90” (BET specific surface area 90 m 2 / g, average
＜疎水化処理＞
気相法シリカ微粒子１００重量部を反応容器に入れ、窒素雰囲気下、以下のポリシロキサン（Ｉ）１１重量部をスプレーした。この反応混合物を２８０℃で１時間、窒素気流下で攪拌した。これを冷却することにより、疎水性シリカを得た。
<Hydrophobic treatment>
100 parts by weight of vapor phase method silica fine particles were put in a reaction vessel, and 11 parts by weight of the following polysiloxane (I) was sprayed in a nitrogen atmosphere. The reaction mixture was stirred at 280 ° C. for 1 hour under a nitrogen stream. By cooling this, hydrophobic silica was obtained.
ポリシロキサン（Ｉ）：一般式（Ｉ）において、Ｒ＝メチル基、Ｒ’＝メチル基、Ｒ”＝メチル基、ｎ＝０、ｍ＝８０、分子量約５９００のポリシロキサン Polysiloxane (I): a polysiloxane of the general formula (I) having R = methyl group, R ′ = methyl group, R ″ = methyl group, n = 0, m = 80, and a molecular weight of about 5900
＜粉砕・分級処理＞
粉砕機としてカウンタージェットミル（ホソカワミクロン社製）を使用し、分級装置としてターボプレックス１０００ＡＴＰ（ホソカワミクロン社製）を用いて粉砕・分級処理を行った。分離した粗粉は配管を通じてジェットミルに連続的に循環導入して、再度粉砕・分級処理に供した。
<Crushing and classification processing>
Using a counter jet mill (manufactured by Hosokawa Micron Corporation) as a pulverizer and a turboplex 1000ATP (manufactured by Hosokawa Micron Corporation) as a classifier, pulverization / classification treatment was performed. The separated coarse powder was continuously circulated and introduced into a jet mill through a pipe and again subjected to pulverization and classification.
得られた疎水化・低凝集化シリカ微粒子について、凝集粒子割合及び疎水率の評価を行って結果を表１に示した。 The obtained hydrophobized / low-aggregated silica fine particles were evaluated for the ratio of aggregated particles and the hydrophobicity, and the results are shown in Table 1.
また、このシリカ微粒子を用いて、以下の配合でトナー組成物を調製し、その評価を行って結果を表１で示した。 Further, a toner composition was prepared by using the silica fine particles with the following composition, evaluated, and the results are shown in Table 1.
＜トナー組成物の調製＞
粉砕法により製造された平均粒子径８μｍの負帯電スチレン−アクリル樹脂２成分トナー（三笠産業社製）を使用し、このトナーとシリカ微粒子との合計１００重量部に対して、シリカ微粒子の配合量が以下の割合となるように混合した。
シリカ微粒子配合量（重量部）
＝親水性シリカ微粒子の平均一次粒子径（ｎｍ）／２０
上記混合物をヘンシェルタイプのミキサーに入れ、６００回転／分で１分間攪拌し、さらに３０００回転／分で３分間攪拌してシリカ微粒子をトナー表面に分散させることによって、トナー組成物を調製した。
<Preparation of toner composition>
A negatively charged styrene-acrylic resin two-component toner (manufactured by Mikasa Sangyo Co., Ltd.) having an average particle diameter of 8 μm produced by a pulverization method is used, and the amount of silica fine particles blended with respect to a total of 100 parts by weight of the toner and silica fine particles. Were mixed so as to have the following ratio.
Silica fine particle content (parts by weight)
= Average primary particle diameter of hydrophilic silica fine particles (nm) / 20
The mixture was placed in a Henschel-type mixer, stirred at 600 rpm for 1 minute, and further stirred at 3000 rpm for 3 minutes to disperse the silica fine particles on the toner surface to prepare a toner composition.
［実施例２〜４、比較例１〜４］
実施例１において、気相法シリカ微粒子として、表１に示すものを用い、疎水化、粉砕・分級条件を変えて疎水化・分級シリカ微粒子を製造し、このシリカ微粒子を用いて同様にトナー組成物を調製した。
[Examples 2 to 4, Comparative Examples 1 to 4]
In Example 1, as the vapor-phase process silica fine particles, those shown in Table 1 were used, and the hydrophobized / classified silica fine particles were produced by changing the hydrophobizing, pulverizing / classifying conditions. A product was prepared.
なお、疎水化処理におけるシリカ微粒子１００重量部当たりのポリシロキサン（Ｉ）の使用量は、疎水化処理に供したシリカ微粒子のＢＥＴ比表面積に応じて、次の式で算出される量とした。
ポリシロキサン（Ｉ）（重量部）
＝親水性シリカ微粒子のＢＥＴ比表面積（ｍ２／ｇ）／８
得られたシリカ微粒子及びトナー組成物の評価結果を表１に示した。
In addition, the usage-amount of polysiloxane (I) per 100 weight part of silica microparticles | fine-particles in a hydrophobization process was made into the quantity calculated by the following formula according to the BET specific surface area of the silica microparticles used for the hydrophobization process.
Polysiloxane (I) (parts by weight)
= BET specific surface area of hydrophilic silica fine particles (m 2 / g) / 8
The evaluation results of the obtained silica fine particles and the toner composition are shown in Table 1.
なお、比較例４で得られた疎水化・分級シリカ微粒子のレーザー回折法による粒子の体積基準粒子径測定における粒度分布を図１に示した。 The particle size distribution of the hydrophobized / classified silica fine particles obtained in Comparative Example 4 in the volume-based particle size measurement by laser diffraction method is shown in FIG.
表１より、本発明によれば、凝集粒子が小さくかつ少なく、トナーへの均一分散性に優れた均一粒子径のシリカ微粒子により、良好な流動性及び画像品質の高いトナー組成物を実現することができることが分かる。 From Table 1, according to the present invention, a toner composition having good fluidity and high image quality can be realized by using silica fine particles having a uniform particle diameter with small and few aggregated particles and excellent uniform dispersibility in the toner. You can see that
Claims (5)
Ｒ”は、炭素数１〜３のアルキル基、水酸基、または両方のＲ”で一つの酸素原子を表して環状シロキサンを形成する結合を表す。
ｎ、ｍは、それぞれ０以上の整数を表し、ｎとｍの合計は２以上である。
なお、Ｒ’はＲとは異なるものであるが、Ｒ’とＲ”、ＲとＲ”は同一であっても良く、異なるものであっても良い。式中の５個のＲは同一のものをさし、２個のＲ”は互いに同一であっても異なっていても良い。） Hydrophobic silica fine particles having an average primary particle diameter of 20 to 100 nm obtained by a vapor phase method are hydrophobized with polysiloxane represented by the following general formula (I), and then only fine powder is recovered by classification after pulverization. Particles obtained by volume-based particle size measurement by laser diffraction performed on an ethanol dispersion of the hydrophobic silica fine particles dispersed by irradiating ultrasonic waves with an intensity of 30 W for 5 minutes. Hydrophobic silica fine particles, characterized in that the proportion of aggregated particles having a diameter of 1.5 μm or more is 10 % or less .
R ″ represents an alkyl group having 1 to 3 carbon atoms, a hydroxyl group, or a bond that represents one oxygen atom in both R ″ to form a cyclic siloxane.
n and m each represent an integer of 0 or more, and the sum of n and m is 2 or more.
Although R ′ is different from R, R ′ and R ″ and R and R ″ may be the same or different. In the formula, five Rs are the same, and two R ″ s may be the same or different.)
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| US12/998,238 US20110177446A1 (en) | 2008-10-01 | 2009-07-29 | Hydrophobic silica microparticles and composition for electrophotographic toner |
| ES09817575T ES2784739T3 (en) | 2008-10-01 | 2009-07-29 | Hydrophobic Silica Fine Particles and Electrophotographic Toner Composition |
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