JP2014058438A - Crystalline alumina laminate particle and method for manufacturing crystalline alumina laminate particle - Google Patents
Crystalline alumina laminate particle and method for manufacturing crystalline alumina laminate particle Download PDFInfo
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 title claims abstract description 306
- 239000002245 particle Substances 0.000 title claims abstract description 173
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims abstract description 11
- 239000006185 dispersion Substances 0.000 claims abstract description 105
- 239000000126 substance Substances 0.000 claims abstract description 35
- 150000004645 aluminates Chemical class 0.000 claims abstract description 9
- 239000002253 acid Substances 0.000 claims abstract description 5
- 150000003839 salts Chemical class 0.000 claims abstract description 5
- 239000010419 fine particle Substances 0.000 claims description 161
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 42
- 239000013078 crystal Substances 0.000 claims description 39
- 238000010335 hydrothermal treatment Methods 0.000 claims description 6
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 claims description 6
- 229910001593 boehmite Inorganic materials 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 229910052783 alkali metal Inorganic materials 0.000 claims description 3
- 150000001340 alkali metals Chemical class 0.000 claims description 3
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 3
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 3
- 150000003863 ammonium salts Chemical class 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 239000002893 slag Substances 0.000 claims 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 abstract description 5
- 238000003756 stirring Methods 0.000 description 53
- 239000007864 aqueous solution Substances 0.000 description 32
- 239000000243 solution Substances 0.000 description 29
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 27
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 20
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 description 20
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 18
- 229910001388 sodium aluminate Inorganic materials 0.000 description 18
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 16
- 238000005406 washing Methods 0.000 description 13
- 239000000725 suspension Substances 0.000 description 12
- 238000010790 dilution Methods 0.000 description 10
- 239000012895 dilution Substances 0.000 description 10
- 229910052757 nitrogen Inorganic materials 0.000 description 10
- 238000000108 ultra-filtration Methods 0.000 description 10
- 241000282994 Cervidae Species 0.000 description 9
- 239000011164 primary particle Substances 0.000 description 9
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 8
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 8
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 8
- 239000000017 hydrogel Substances 0.000 description 8
- 229910052708 sodium Inorganic materials 0.000 description 8
- 239000011734 sodium Substances 0.000 description 8
- 239000012452 mother liquor Substances 0.000 description 7
- 230000003287 optical effect Effects 0.000 description 7
- 239000011163 secondary particle Substances 0.000 description 7
- 125000003698 tetramethyl group Chemical group [H]C([H])([H])* 0.000 description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 6
- 238000003917 TEM image Methods 0.000 description 6
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 6
- 238000005452 bending Methods 0.000 description 6
- 238000007872 degassing Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 229910017604 nitric acid Inorganic materials 0.000 description 5
- 239000012071 phase Substances 0.000 description 5
- -1 Showa Denko H-42 Chemical compound 0.000 description 4
- 230000002776 aggregation Effects 0.000 description 4
- 238000004220 aggregation Methods 0.000 description 4
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 239000000945 filler Substances 0.000 description 4
- 238000010304 firing Methods 0.000 description 4
- 150000007522 mineralic acids Chemical class 0.000 description 4
- 239000002105 nanoparticle Substances 0.000 description 4
- 150000007524 organic acids Chemical class 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical class [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000499 gel Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 229910001867 inorganic solvent Inorganic materials 0.000 description 3
- 239000003049 inorganic solvent Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 238000001139 pH measurement Methods 0.000 description 3
- 239000003973 paint Substances 0.000 description 3
- 239000011780 sodium chloride Substances 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- BAVYZALUXZFZLV-UHFFFAOYSA-O Methylammonium ion Chemical compound [NH3+]C BAVYZALUXZFZLV-UHFFFAOYSA-O 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 239000002537 cosmetic Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000009970 fire resistant effect Effects 0.000 description 2
- 239000003063 flame retardant Substances 0.000 description 2
- 239000003779 heat-resistant material Substances 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000011541 reaction mixture Substances 0.000 description 2
- 239000012266 salt solution Substances 0.000 description 2
- 235000010344 sodium nitrate Nutrition 0.000 description 2
- 239000004317 sodium nitrate Substances 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- 235000011152 sodium sulphate Nutrition 0.000 description 2
- 238000003980 solgel method Methods 0.000 description 2
- QEMXHQIAXOOASZ-UHFFFAOYSA-N tetramethylammonium Chemical compound C[N+](C)(C)C QEMXHQIAXOOASZ-UHFFFAOYSA-N 0.000 description 2
- 238000004448 titration Methods 0.000 description 2
- XNDZQQSKSQTQQD-UHFFFAOYSA-N 3-methylcyclohex-2-en-1-ol Chemical compound CC1=CC(O)CCC1 XNDZQQSKSQTQQD-UHFFFAOYSA-N 0.000 description 1
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 238000007696 Kjeldahl method Methods 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- KVLCHQHEQROXGN-UHFFFAOYSA-N aluminium(1+) Chemical compound [Al+] KVLCHQHEQROXGN-UHFFFAOYSA-N 0.000 description 1
- 229940007076 aluminum cation Drugs 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- 239000000908 ammonium hydroxide Substances 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 229910052809 inorganic oxide Inorganic materials 0.000 description 1
- 229910017053 inorganic salt Inorganic materials 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000003002 pH adjusting agent Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000012086 standard solution Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- HKOFYHZIMHRMSJ-UHFFFAOYSA-K trichloroalumane nonahydrate Chemical compound O.O.O.O.O.O.O.O.O.[Al+3].[Cl-].[Cl-].[Cl-] HKOFYHZIMHRMSJ-UHFFFAOYSA-K 0.000 description 1
Landscapes
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
Description
本発明は、複数の正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子と該結晶性アルミナ積層粒子の製造方法に関する。 The present invention relates to a crystalline alumina laminated particle having a structure in which a plurality of square plate-like alumina fine particles are laminated without overlapping at least two sides, and a method for producing the crystalline alumina laminated particle.
本願発明は、複数の正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子であり、該結晶性アルミナ積層粒子を構成する正方板状アルミナ微粒子については、多数の報告がなされている。 The present invention is a crystalline alumina laminated particle having a structure in which a plurality of square plate-like alumina fine particles are laminated without overlapping at least two sides. About the square plate-like alumina fine particles constituting the crystalline alumina laminated particles, Many reports have been made.
特許文献１では、金属塩の水溶液を水の亜臨界ないし超臨界条件である２００℃以上、１６０ｋｇ／ｃｍ2以上で処理し、金属酸化物の水和物であるオキシ水酸化物も含む金属酸化物微粒子の製造方法が開示されている。この粒子の特徴として、粒度分布が狭く、形状もそろい、結晶性が高く、枝分かれ、双晶がなく２次凝集の少ないことがあげられる。 In Patent Document 1, an aqueous solution of a metal salt is treated at 200 ° C. or higher and 160 kg / cm 2 or higher, which is a subcritical or supercritical condition of water, and a metal oxide containing an oxyhydroxide that is a hydrate of a metal oxide. A method for producing physical particles is disclosed. The characteristics of the particles are that the particle size distribution is narrow, the shapes are uniform, the crystallinity is high, there are no branches and twins, and there is little secondary aggregation.
また特許文献２には、水酸化アルミニウムと、(メタ)アクリル酸エステル系の重合体とを、ｐＨ調整剤としてナトリウム、カリウム、バリウム、カルシウムおよびストロンチウムより選ばれる少なくとも１種の水酸化物またはアルミン酸塩を添加してｐＨ８以上にした状態で１３０〜２５０℃の温度で水熱処理することで板状ベーマイトアルミナの製造方法が開示されている。 Patent Document 2 discloses that aluminum hydroxide and a (meth) acrylic acid ester-based polymer are used as a pH adjuster and at least one hydroxide or alumina selected from sodium, potassium, barium, calcium and strontium. The manufacturing method of plate-like boehmite alumina is disclosed by hydrothermally treating at a temperature of 130 to 250 ° C. with an acid salt added to a pH of 8 or higher.
さらにナノサイズのアルミナ複合酸化物微粒子として、特許文献３にはアルミニウム金属塩水溶液とアルカリ水溶液とを反応させ、ゲル状物質を含む反応混合物を予め製造することで、ベーマイトアルミナ微粒子をゲル中に取り込むという、ゾルゲル法を用いることによりアルミナ微粒子同士の癒着、凝集を防ぐことでナノサイズのアルミナ微粒子が開示されている。 Furthermore, as nano-sized alumina composite oxide fine particles, Patent Document 3 discloses that a boehmite alumina fine particle is incorporated into a gel by reacting an aqueous aluminum metal salt solution with an alkaline aqueous solution to produce a reaction mixture containing a gel substance in advance. Nano-sized alumina fine particles are disclosed by preventing adhesion and aggregation of alumina fine particles by using the sol-gel method.
特許文献４にはアルミニウム金属塩水溶液中にアルカリ水溶液を添加し、得られた反応混合物中に水酸化アルミニウムのゲル状物質を予め製造することで、ベーマイトアルミナ微粒子をゲル中に取り込むという、ゾルゲル法を用いることによりアルミナ微粒子同士の癒着、凝集を防ぐことでナノサイズのアルミナ微粒子が開示されている。また、得られたアルミナ微粒子は、内部に中空部を有することが開示され、無機充填剤、軽量無機質成形体などの用途が開示されている。 Patent Document 4 discloses a sol-gel method in which an aqueous alkali solution is added to an aqueous aluminum metal salt solution, and a gel-like substance of aluminum hydroxide is preliminarily produced in the obtained reaction mixture, thereby incorporating boehmite alumina fine particles into the gel. Nano-sized alumina fine particles have been disclosed by preventing adhesion and aggregation between the alumina fine particles. Moreover, it is disclosed that the obtained alumina fine particle has a hollow part inside, and uses such as an inorganic filler and a lightweight inorganic molded body are disclosed.
しかしながら、正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子についての開示は見られず、その存在についての示唆すらされていない。さらには、その粒子の用途についてもあまり知られていない。 However, there is no disclosure of crystalline alumina laminated particles having a structure in which square plate-like alumina fine particles are laminated without overlapping at least two sides, and there is no suggestion about their existence. Furthermore, little is known about the use of the particles.
本発明は、複数の正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子と該結晶性アルミナ積層粒子の製造方法を提供することを目的としている。 An object of the present invention is to provide a crystalline alumina laminated particle having a structure in which a plurality of square plate-like alumina fine particles are laminated without overlapping at least two sides, and a method for producing the crystalline alumina laminated particle.
（１） 複数の正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子。
（２） 前記正方板状アルミナ微粒子は、平均粒子径が２〜１００ｎｍ、平均厚みが１〜２０ｎｍの範囲にあり、アスペクト比（平均粒子径／平均厚み）が２〜５０の範囲であることを特徴とする上記(１)に記載の結晶性アルミナ積層粒子。
（３） 前記正方板状アルミナ微粒子の平均積層数が、３〜２０であることを特徴とする上記（１）または（２）に記載の結晶性アルミナ積層粒子。
（４） 前記正方板状アルミナ微粒子は、ベーマイト結晶相のアルミナを主成分とすることを特徴とする上記（１）〜（３）のいずれかに記載の結晶性アルミナ積層粒子。
（５） 前記結晶性アルミナ積層粒子は、平均長軸の長さが１０〜３００ｎｍ、平均厚みが２〜５０ｎｍの範囲にあることを特徴とする上記（１）〜（４）のいずれかに記載の結晶性アルミナ積層粒子。
（６） 前記結晶性アルミナ積層粒子において、２００℃で焼成した時の比表面積（ＳＡ１）と３５０℃で焼成した時の比表面積（ＳＡ２）の比（（ＳＡ２）／（ＳＡ１））が、０．７０〜０．９５の範囲にあることを特徴とする上記（１）〜（５）のいずれかに記載の結晶性アルミナ積層粒子。
（７） (Ａ)正方板状アルミナ微粒子の分散液を水熱処理することにより複数の正方板状のアルミナ微粒子が、少なくとも２辺が重ならないように積層した構造をなす結晶性アルミナ積層粒子分散液を得る工程
（Ｂ）前記工程（Ａ）で得られた結晶性アルミナ積層粒子から残留する塩基性物質を除去し、結晶性アルミナ積層粒子分散液を得る工程
を含むことを特徴とする上記（１）〜（６）のいずれかに記載の結晶性アルミナ積層粒子の製造方法。
（８） (７)の工程（Ａ）で用いる正方板状アルミナ微粒子が
（ａ）アルミン酸塩溶液に酸を添加した後、５０〜１００℃の温度で処理することにより１０〜１２の範囲にあるｐＨを有する正方板状アルミナ微粒子分散液を得る工程
（ｂ）前記工程（ａ）において得られた正方板状アルミナ微粒子分散液から残留する溶解性無機塩および未反応物質を除去する工程
（ｃ）前記工程（ｂ）で得られた正方板状アルミナ微粒子分散液に、さらに塩基性物質を添加して前記正方板状アルミナ微粒子の大きさを均一化する工程
を含むことを特徴とする（７）に記載の結晶性アルミナ積層粒子の製造方法。
（９） 前記工程（ｃ）において、塩基性物質として、アルカリ金属、アルカリ土類金属およびアンモニウムの塩で水に可溶な化合物から選ばれる少なくとも１種を用いることを特徴とする上記（８）に記載の結晶性アルミナ積層粒子の製造方法。
（１０） 前記工程（Ａ）で用いる正方板状アルミナ微粒子の分散液が
（ｄ）工程（ａ）および工程（ｂ）を含まない工程により得られた正方板状アルミナ微粒子を分散液としたのち塩基性物質を添加して前記正方板状アルミナ微粒子の大きさを均一化する工程
によって得られたものであることを特徴とする上記（７）に記載の結晶性アルミナ積層粒子の製造方法。
（１１） 前記工程（Ａ）において、水熱処理の温度が１１０〜１８０℃、水熱処理時間が１５〜５０時間の範囲であることを特徴とする上記（７〜１０）に記載の結晶性アルミナ積層粒子の製造方法。
（１２） 前記工程（Ｂ）で得られた結晶性アルミナ積層粒子分散液中に残存する残留塩基物質の濃度が１００ｐｐｍ以下であることを特徴とする上記（７）〜（１１）のいずれかに記載の結晶性アルミナ積層粒子の製造方法。
(1) Crystalline alumina laminated particles having a structure in which a plurality of square plate-like alumina fine particles are laminated without overlapping at least two sides.
(2) The square plate-like alumina fine particles have an average particle diameter of 2 to 100 nm, an average thickness of 1 to 20 nm, and an aspect ratio (average particle diameter / average thickness) of 2 to 50. The crystalline alumina laminated particle according to the above (1), which is characterized by the following.
(3) The crystalline alumina laminated particles according to (1) or (2) above, wherein the average number of laminated square plate-like alumina fine particles is 3 to 20.
(4) The crystalline alumina laminated particles according to any one of (1) to (3) above, wherein the square plate-like alumina fine particles are mainly composed of alumina in a boehmite crystal phase.
(5) The crystalline alumina laminated particles according to any one of (1) to (4) above, wherein the average major axis has a length of 10 to 300 nm and an average thickness of 2 to 50 nm. Crystalline alumina laminated particles.
(6) The ratio of the specific surface area (SA1) when fired at 200 ° C. to the specific surface area (SA2) when fired at 350 ° C. ((SA2) / (SA1)) is 0 The crystalline alumina laminated particle according to any one of the above (1) to (5), which is in a range of .70 to 0.95.
(7) (A) Crystalline alumina laminated particle dispersion having a structure in which a plurality of square plate-like alumina fine particles are laminated so that at least two sides do not overlap by hydrothermal treatment of a dispersion of square plate-like alumina fine particles (B) The step of removing the basic substance remaining from the crystalline alumina laminated particles obtained in the step (A) to obtain a crystalline alumina laminated particle dispersion (1) above )-(6) The manufacturing method of the crystalline alumina laminated particle in any one of.
(8) The square plate-like alumina fine particles used in the step (A) of (7) are (a) after adding an acid to the aluminate solution, and then treating at a temperature of 50 to 100 ° C. to a range of 10 to 12 A step of obtaining a square plate-like alumina fine particle dispersion having a certain pH (b) a step of removing the remaining soluble inorganic salts and unreacted substances from the square plate-like alumina fine particle dispersion obtained in the step (a) (c) And (b) adding a basic substance to the square plate-like alumina fine particle dispersion obtained in the step (b) to make the size of the square plate-like alumina fine particles uniform. ) For producing crystalline alumina laminated particles.
(9) In the step (c), at least one selected from water-soluble alkali metal, alkaline earth metal and ammonium salts is used as the basic substance. The manufacturing method of the crystalline alumina laminated particle as described in any one of.
(10) A dispersion of square plate-like alumina fine particles used in the step (A) (d) After the square plate-like alumina fine particles obtained by the step not including the steps (a) and (b) are used as a dispersion The method for producing crystalline alumina laminated particles according to (7) above, which is obtained by a step of adding a basic substance to uniformize the size of the square plate-like alumina fine particles.
(11) In the step (A), the temperature of the hydrothermal treatment is in the range of 110 to 180 ° C., and the hydrothermal treatment time is in the range of 15 to 50 hours. Particle manufacturing method.
(12) In any one of the above (7) to (11), the concentration of the residual basic substance remaining in the crystalline alumina laminated particle dispersion obtained in the step (B) is 100 ppm or less. The manufacturing method of crystalline alumina laminated particle of description.
本発明は、複数の正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子と該結晶性アルミナ積層粒子の製造方法を提供することができる。 The present invention can provide a crystalline alumina laminated particle having a structure in which a plurality of square plate-like alumina fine particles are laminated without overlapping at least two sides, and a method for producing the crystalline alumina laminated particle.
本発明の結晶性アルミナ積層粒子は、複数の正方板状アルミナ微粒子の集合したものであり粒子表面の凹凸を利用して研磨材としての利用でき、板状という形態から膜強度（曲げ強度、曲げ弾性率、荷重たわみ強度等）向上を狙った樹脂フィラーとして利用できる。 The crystalline alumina laminated particle of the present invention is an aggregate of a plurality of square plate-like alumina fine particles, and can be used as an abrasive by utilizing the irregularities on the particle surface. From the form of plate, film strength (bending strength, bending strength) (Elastic modulus, load deflection strength, etc.) It can be used as a resin filler aiming at improvement.
また、粒子表面は複数の正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造であるため、ナノオーダーのフラクタル状の凹凸が形成されている。そのため、その凹凸に起因する光学特性を利用した化粧品、樹脂フィラー、表面コート材（光学散乱、屈折率調整など）へ応用することができる。 Further, since the particle surface has a structure in which a plurality of square plate-like alumina fine particles are laminated without overlapping at least two sides, nano-order fractal irregularities are formed. Therefore, it can be applied to cosmetics, resin fillers, and surface coating materials (optical scattering, refractive index adjustment, etc.) that utilize optical characteristics due to the unevenness.
さらに、表面電荷と粒子形状の相乗効果で有機・無機溶剤塗料等への混合の自由度が広く、耐火難燃材、耐熱材として塗布／成型に利用できる。 Furthermore, the degree of freedom of mixing into organic and inorganic solvent paints is wide due to the synergistic effect of surface charge and particle shape, and it can be used for coating / molding as a fire-resistant flame retardant material and heat-resistant material.
以下に、まず本発明に係る結晶性アルミナ積層粒子について説明する。
＜正方板状アルミナ微粒子＞
正方板状アルミナ微粒子の１次粒子の大きさは、アルミナ水和物微粒子の透過型電子顕微鏡写真（ＴＥＭ）を撮影し、５０個の粒子について粒子径および厚みを測定し、各々の平均値を求めることができ、平均粒子径が２〜１００ｎｍ、さらに３〜８０ｎｍの範囲にあることが好ましく、平均厚みが１〜２０ｎｍ、さらには２〜１５ｎｍの範囲にあることが好ましい。また、この時、平均粒子径と平均厚みの比（アスペクト比）は、２〜５０の範囲にある板状形態にすることが必要である。アスペクト比が1以下の場合、積層した構造をとりにくくなり、塊状となる傾向がある。
Hereinafter, the crystalline alumina laminated particles according to the present invention will be described first.
<Square plate-like alumina fine particles>
The size of the primary particles of the square plate-like alumina fine particles is obtained by taking a transmission electron micrograph (TEM) of the alumina hydrate fine particles, measuring the particle diameter and thickness of 50 particles, and calculating the average value of each. The average particle diameter is preferably in the range of 2 to 100 nm, more preferably 3 to 80 nm, and the average thickness is preferably 1 to 20 nm, more preferably 2 to 15 nm. At this time, the ratio of the average particle diameter to the average thickness (aspect ratio) needs to be a plate-like form in the range of 2-50. When the aspect ratio is 1 or less, it is difficult to take a laminated structure, and there is a tendency to form a lump.
アルミナ微粒子の１次粒子としては、アルミナ水和物微粒子であればよく、制限はない。特に本発明では、ベーマイトアルミナ水和物微粒子が好ましい。
市販の正方板状形状を有するベーマイトアルミナ水和物微粒子、例えば、Ｓａｓｏｌ社製 ＤＩＳＰＥＲＡＬ―Ｐ２、ＣＡＴＡＰＡＬ―Ａ、ＰＵＲＡＬ―ＳＢ、水酸化アルミニウム微粒子、例えば、ＵＯＰ社製 ＶＥＲＳＡＬ―Ｒ３、日本軽金属社製 Ｂ７０３、Ｂ１４０３、昭和電工社製Ｈ―４２、Ｈ―４３などを好適に使用することができる。
＜結晶性アルミナ積層粒子＞
本願発明の結晶性アルミナ積層粒子は、ナノサイズのアルミナ微粒子同士が結晶面を揃えて積み重なるのではなく、ずれた状態（オフセット状態）で積層することにより、複数のアルミナ微粒子同士が、少なくとも２辺が重なることなく積層した構造となす粒子となる。
The primary particles of the alumina fine particles are not particularly limited as long as they are alumina hydrate fine particles. In the present invention, boehmite alumina hydrate fine particles are particularly preferable.
Boehmite alumina hydrate fine particles having a square plate shape on the market, such as DISPERAL-P2, CATAPAL-A, PURAL-SB, aluminum hydroxide fine particles made by Sasol, for example, VERSAL-R3 made by UOP, made by Nippon Light Metal Co., Ltd. B703, B1403, Showa Denko H-42, H-43, etc. can be suitably used.
<Crystalline alumina laminated particles>
In the crystalline alumina laminated particle of the present invention, the nano-sized alumina fine particles are not stacked with the crystal planes aligned, but are laminated in a shifted state (offset state), so that the plurality of alumina fine particles have at least two sides. The particles become a laminated structure without overlapping.
結晶性アルミナ積層粒子の積層数は３〜２０である。大きさは、平均長軸の長さが１０〜３００ｎｍ、平均厚みが２〜５０ｎｍの範囲である。
結晶性アルミナ積層粒子の大きさは、透過型電子顕微鏡写真（ＴＥＭ）を用い、５０個の粒子について、長軸と短軸の長さおよび厚みを計測し、長軸の長さの平均値および厚みの平均値を求めることができる。
The number of laminated layers of crystalline alumina laminated particles is 3-20. The size is in the range where the length of the average major axis is 10 to 300 nm and the average thickness is 2 to 50 nm.
The size of the crystalline alumina laminated particles was measured using the transmission electron micrograph (TEM), and the length and thickness of the major axis and minor axis were measured for 50 particles, and the average value of the major axis length and The average value of the thickness can be obtained.
また、結晶性アルミナ積層粒子の積層状態は、透過型電子顕微鏡写真（ＴＥＭ）により確認することができる。
一般に、アルミニウムは両性酸化物であるため、低ｐＨ領域では水分子を６つ配位した６配位型アルミニウムカチオン[Ａｌ（ＯＨ2）6]3+をとり、これをｐＨ４以下の範囲で中和してできるアルミナヒドロゲルは、６配位型構造をもつＡｌ（ＯＨ）3を単位ユニットとした８面体構造を形成し、単位ユニットの辺と頂点を共有したベーマイト構造をとる。
Moreover, the lamination | stacking state of crystalline alumina laminated particle can be confirmed with a transmission electron micrograph (TEM).
In general, since aluminum is an amphoteric oxide, in the low pH region, it takes a six-coordinated aluminum cation [Al (OH 2 ) 6 ] 3+ in which six water molecules are coordinated. The resulting alumina hydrogel forms an octahedral structure in which Al (OH) 3 having a hexacoordinate structure is a unit unit, and has a boehmite structure in which the side and apex of the unit unit are shared.
さらに、共存するアニオンの影響で結晶軸のａ、ｂ軸方向の成長よりｃ軸の成長が早く、ウィスカー（針）〜ロッド（柱）状の１次粒子形状をとる。
逆に高ｐＨ領域では、４配位型のテトラヒドロキソアルミニウムアニオン[Ａｌ（ＯＨ）4]-をとり、これをｐＨ１０以上の範囲で中和してできるアルミナヒドロゲルは４配位型構造をもつ[Ａｌ（ＯＨ）4]を単位ユニットとした４面体構造を形成し、単位ユニットの稜と辺を酸素元素による架橋結合（μ-ＯＨタイプ）した擬ベーマイト構造となる。
Further, the growth of the c-axis is faster than the growth of the crystal axes in the a- and b-axis directions due to the influence of the coexisting anions, and it takes a primary particle shape of a whisker (needle) to a rod (column).
At high pH, on the other hand, tetra-hydroxo aluminum anions tetracoordinate-type [Al (OH) 4] - is taken up, which alumina hydrogel can be neutralized in a range of pH10 above has a 4-coordinated structure [ A tetrahedron structure having Al (OH) 4 ] as a unit unit is formed, and a quasi-boehmite structure in which the ridges and sides of the unit unit are cross-linked (μ-OH type) with an oxygen element.
さらに、共存するカチオンの影響で結晶軸のａ軸よりもｂ、ｃ軸の成長が早く、板状の１次粒子形状をとる。
このアルミナの性質を利用し、選択的に４配位型構造を単位ユニットとするアルミナヒドロゲルを調製し、その構造を保持したまま結晶成長させることが可能なｐＨ範囲で本発明の１次粒子であるアルミナ微粒子を得られる。
Further, the growth of the b and c axes is faster than the a axis of the crystal axis due to the coexisting cations, and it takes a plate-like primary particle shape.
Utilizing the properties of alumina, an alumina hydrogel having a tetracoordinate structure as a unit unit is selectively prepared, and the primary particles of the present invention are used in the pH range where crystals can be grown while maintaining the structure. A certain alumina fine particle can be obtained.
本発明のように、アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をもつ結晶性アルミナ積層粒子が得られた理由は明確ではないが、上記のように結晶の成長軸を規定したアルミナ微粒子を調製し、さらに該微粒子の表面電荷が低いこと、面間に塩基性物質等のイオン性物質の残存が少ないことから粒子面同士の相互作用が弱いことから、粒子の辺または頂点の電荷に支配され、少なくとも２辺が重なることなく積層し、さらに制御された成長軸方向に伸びた構造をもつ粒子が得られたという結晶成長機構と１次粒子であるアルミナ微粒子が積層するとき、アルミナ微粒子自身、表面電荷を有しており、アルミナ微粒子同士が近づいたとき、各々微粒子の表面電荷で誘電分極が起こり、分極が中和される位置で積層した結晶性アルミナ積層粒子が得ら、さらに結晶成長面が制御されているため、成長軸方向に成長したという結晶成長機構を推定している。 The reason why the crystalline alumina laminated particles having a structure in which the alumina fine particles are laminated without overlapping at least two sides as in the present invention is not clear, but the alumina in which the crystal growth axis is defined as described above. Since the fine particles are prepared and the surface charge of the fine particles is low, and the interaction between the particle surfaces is weak because there is little residual ionic substance such as a basic substance between the surfaces, the charge on the side or vertex of the particles When the crystal growth mechanism in which particles having a structure extending in the direction of the controlled growth axis and the primary particles are laminated are laminated, the alumina fine particles are laminated. The fine particles themselves have surface charges, and when the alumina fine particles approach each other, dielectric polarization occurs due to the surface charges of the fine particles, and the crystals are stacked at the position where the polarization is neutralized. Since the alumina layered particles obtained et al, are further crystal growth surface control, estimates the crystal growth mechanism that has grown in the growth axis direction.
さらに、積層して得られた本発明の結晶性アルミナ積層粒子の粒子表面は、ナノオーダーの凹凸（フラクタル表面）が形成されており、この凹凸を利用した研磨材のみならず光学系材料などにも利用するができる。 Furthermore, nano-order irregularities (fractal surface) are formed on the particle surface of the crystalline alumina laminated particles of the present invention obtained by laminating, and not only for abrasives using these irregularities but also for optical system materials, etc. Can also be used.
少なくとも２辺が重なることなく積層した構造の具体例としては、一方向に傾斜して階段状に積層するもの、４辺がすべて重なることなく傾斜して積層するもの等が含まれるが、これらに限られない。なお４辺がすべて重なって積層する形態は本発明には含まれない。
・比表面積と1次粒子径の関係
一般的に粒子成長には、３つの結晶軸の成長速度が、Ｉ．結晶軸すべてほぼ同じ速度で成長する場合、II．結晶軸の成長速度が異なる場合に大別される。１次粒子の平均粒子径の成長に伴う比表面積の変動量は、Iの場合では大きく、IIの場合では小さくなる傾向を示す。
Specific examples of the structure in which at least two sides are stacked without overlapping each other include those that are inclined in one direction and stacked in a staircase pattern, and those that are stacked with all four sides inclined without overlapping, etc. Not limited. In addition, the form which laminates | stacks all four sides is not included in this invention.
・ Relationship between specific surface area and primary particle size In general, the growth rate of three crystal axes is I.V. When all crystal axes grow at almost the same speed, II. It is divided roughly when the growth rate of crystal axes is different. The fluctuation amount of the specific surface area accompanying the growth of the average particle diameter of the primary particles tends to be large in the case of I and small in the case of II.
さらに、比表面積と結晶成長軸の数との関係に着目すると、結晶成長軸の数が３軸（3軸とも成長する）の場合が、最も比表面積の減衰が早く起こる傾向があり、結晶成長軸の数が2本、1本となるにつれて、減衰が緩慢になる傾向を示す。結晶軸の模式図と、減衰の傾向の模式図をそれぞれ図１および図２に示す。図２において、横軸は時間軸であり、縦軸は比表面積を示す。 Furthermore, focusing on the relationship between the specific surface area and the number of crystal growth axes, when the number of crystal growth axes is three axes (all three axes grow), the specific surface area tends to decay most rapidly. As the number of axes becomes two or one, the attenuation tends to become slow. A schematic diagram of the crystal axis and a schematic diagram of the tendency of attenuation are shown in FIGS. 1 and 2, respectively. In FIG. 2, the horizontal axis is the time axis, and the vertical axis indicates the specific surface area.
本発明の結晶性アルミナ積層粒子は、正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をもつことを特徴としている。正方板状アルミナ微粒子の平均粒子径を変化させて結晶性アルミナ積層粒子を製造した場合、正方板状アルミナ微粒子の平均粒子径が大きくなる変化量と、比表面積の変動量がそれほど大きな変化をしなくなる傾向を示し、比表面積はあるレベルの比表面積の値（ｍ2／ｇ）以下には見かけ上低がらなくなる（減衰する）という傾向がある。 The crystalline alumina laminated particle of the present invention is characterized by having a structure in which square plate-like alumina fine particles are laminated without overlapping at least two sides. When crystalline alumina laminated particles are produced by changing the average particle size of the square plate-like alumina fine particles, the amount of change in which the average particle size of the square plate-like alumina fine particles becomes large and the amount of change in the specific surface area change so much. The specific surface area tends to disappear (decay) apparently below a certain level of specific surface area value (m 2 / g).
以上のことからも、本発明の結晶性アルミナ積層粒子は、特定の結晶軸方向に結晶成長していることが示唆され、正方板状アルミナ微粒子が特定の結晶軸方向にのみ成長していることを示唆しているものと考えられる。
・比表面積と焼成の関係
さらに、本発明の結晶性アルミナ積層粒子の表面積において、２００℃で焼成した時の表面積（ＳＡ１）と３５０℃で焼成した時の比表面積（ＳＡ２）の比（（ＳＡ２）／（ＳＡ１））が、０．７０〜０．９５の範囲にあり、さらには０．７５〜０．９３の範囲にあることが好ましい。
From the above, it is suggested that the crystalline alumina laminated particles of the present invention grow in the specific crystal axis direction, and that the square plate-like alumina fine particles grow only in the specific crystal axis direction. This is thought to suggest.
-Relationship between specific surface area and firing Further, in the surface area of the crystalline alumina laminated particles of the present invention, the ratio of the surface area (SA1) when fired at 200 ° C to the specific surface area (SA2) when fired at 350 ° C ((SA2 ) / (SA1)) is in the range of 0.70 to 0.95, more preferably in the range of 0.75 to 0.93.
無機酸化物粒子の表面積は、焼成温度が上昇すると比表面積は小さくなる傾向を示す。これは、粒子の細孔が焼成により減少することに起因し、比表面積が低下する現象が起こる。 The surface area of the inorganic oxide particles tends to decrease as the firing temperature increases. This is due to the fact that the pores of the particles are reduced by firing, and a phenomenon occurs in which the specific surface area decreases.
本発明の結晶性アルミナ積層粒子は、焼成温度を高くしても比表面積の変化は小さく１次粒子のもつ表面積のオーダーから極端に下がる現象は見られない。このことから、正方板状アルミナ微粒子が、少なくとも２辺は重ならないが、結晶平面をある程度保持して積層した構造を形成していることを示唆していると考えられる。 In the crystalline alumina laminated particles of the present invention, the change in specific surface area is small even when the firing temperature is increased, and a phenomenon of extremely decreasing from the order of the surface area of the primary particles is not observed. From this, it is considered that the square plate-like alumina fine particles do not overlap at least two sides, but form a laminated structure while maintaining a crystal plane to some extent.
このような、積層構造を形成することで、粒子表面にはナノオーダーの凹凸（フラクタル表面）が形成されているものと考えられる。走査型電子顕微鏡（日立ハイテクノロジーズ株式会社製、Ｈ−５５００）によるＳＥＭ写真を図３に示す。
＜結晶性アルミナ積層粒子の製造方法＞
本発明に係る結晶性アルミナ積層粒子の製造方法は、
（Ａ）正方板状アルミナ微粒子の分散液を水熱処理することにより複数の正方板状のアルミナ微粒子が、少なくとも２辺が重ならないように積層した構造をなす結晶性アルミナ積層粒子分散液を得る工程
（Ｂ）前記工程（Ａ）で得られた結晶性アルミナ積層粒子から残留する塩基性物質を除去し、結晶性アルミナ積層粒子分散液を得る工程
を含むものである。
By forming such a laminated structure, it is considered that nano-order unevenness (fractal surface) is formed on the particle surface. The SEM photograph by a scanning electron microscope (Hitachi High-Technologies Corporation make, H-5500) is shown in FIG.
<Method for producing crystalline alumina laminated particle>
The method for producing crystalline alumina laminated particles according to the present invention includes:
(A) A step of obtaining a crystalline alumina laminated particle dispersion having a structure in which a plurality of square plate-like alumina fine particles are laminated so that at least two sides do not overlap by hydrothermally treating a dispersion of square plate-like alumina fine particles. (B) A step of removing the remaining basic substance from the crystalline alumina laminated particles obtained in the step (A) to obtain a crystalline alumina laminated particle dispersion.
正方板状アルミナ微粒子の分散液は、以下の(ａ)から（ｃ）の工程を含むことによって得られるものであることが好ましい。
但し、工程（ａ）および（ｂ）を含まない工程により得られた正方板状アルミナ微粒子を用いることもでき、その場合は工程（ｄ）により正方板状アルミナ微粒子の分散液を得ることができる。工程（ａ）および（ｂ）を含まない工程により得られた正方板状アルミナ微粒子の例としては、前述のベーマイトアルミナ水和物微粒子、例えば、Ｓａｓｏｌ社製 ＤＩＳＰＥＲＡＬ―Ｐ２、ＣＡＴＡＰＡＬ―Ａ、ＰＵＲＡＬ―ＳＢ、水酸化アルミニウム微粒子、例えば、ＵＯＰ社製 ＶＥＲＳＡＬ―Ｒ３、日本軽金属社製 Ｂ７０３、Ｂ１４０３、昭和電工社製Ｈ―４２、Ｈ―４３などが挙げられる。
The dispersion of square plate-like alumina fine particles is preferably obtained by including the following steps (a) to (c).
However, square plate-like alumina fine particles obtained by a step not including steps (a) and (b) can also be used, and in that case, a dispersion of square plate-like alumina fine particles can be obtained by step (d). . Examples of the square plate-like alumina fine particles obtained by the process not including steps (a) and (b) include the boehmite alumina hydrate fine particles described above, for example, DISPERAL-P2, CATAPAL-A, PURAL- SB, aluminum hydroxide fine particles, for example, VERSAL-R3 manufactured by UOP, B703, B1403 manufactured by Nippon Light Metal Co., Ltd., H-42, H-43 manufactured by Showa Denko KK and the like can be mentioned.
（ａ）アルミン酸塩溶液に酸を添加した後、所定の温度で処理することにより所定のｐＨを有する正方板状アルミナ微粒子分散液を得る工程
（ｂ）前記工程（ａ）で得られた正方板状アルミナ微粒子分散液から残留する溶解性無機塩および未反応物質を除去する工程
（ｃ）前記工程（ｂ）で得られた正方板状アルミナ微粒子分散液に塩基性物質を添加して処理することによりの大きさを均一化した正方板状アルミナ微粒子分散液を得る工程
正方板状アルミナ微粒子として市販品を用いる場合は、工程（ｄ）により大きさを均一化した正方板状アルミナ微粒子分散液を得ることができる。
(A) Step of obtaining a square plate-like alumina fine particle dispersion having a predetermined pH by adding an acid to the aluminate solution and then treating at a predetermined temperature (b) The square obtained in the step (a) Step of removing residual soluble inorganic salt and unreacted substance from plate-like alumina fine particle dispersion (c) A basic substance is added to the square plate-like alumina fine particle dispersion obtained in the above step (b) for treatment. Step of obtaining a square plate-like alumina fine particle dispersion whose size has been made uniform When using a commercial product as the square plate-like alumina fine particle, a square plate-like alumina fine particle dispersion whose size has been made uniform in step (d) Can be obtained.
（ｄ）工程（ａ）および工程（ｂ）を含まない工程により得られた正方板状アルミナ微粒子を分散液としたのち塩基性物質を添加して前記正方板状アルミナ微粒子の大きさを均一化する工程
次に、この製造方法について各工程を説明すれば、以下のとおりである。
＜工程（Ａ）＞
この工程では、上記工程（ａ）〜（ｃ）、または工程（ｄ）により得られた大きさの揃った塩基性物質添加アルミナ微粒子分散液を処理温度１１０〜１８０℃、処理時間１〜３０時間の範囲で水熱処理をすることで複数の正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子分散液を得る。
(D) After making the square plate-like alumina fine particles obtained by the step (a) and the step not including the step (b) into a dispersion, a basic substance is added to uniformize the size of the square plate-like alumina fine particles. Next, the steps of the manufacturing method will be described as follows.
<Process (A)>
In this step, the basic substance-added alumina fine particle dispersion having the same size obtained in the steps (a) to (c) or the step (d) is treated at a treatment temperature of 110 to 180 ° C. and a treatment time of 1 to 30 hours. By carrying out the hydrothermal treatment in the above range, a crystalline alumina laminated particle dispersion having a structure in which a plurality of square plate-like alumina fine particles are laminated without overlapping at least two sides is obtained.
処理温度は、範囲下限未満では少なくとも２辺が重なることなく積層した構造への進行が進まない可能性があり、範囲上限を超えると凝集しやすくなる傾向にあるので好ましくない。 If the treatment temperature is less than the lower limit of the range, there is a possibility that the progress to the laminated structure does not proceed without overlapping at least two sides.
処理時間は、上記の範囲から適宜選択した条件で処理することが好ましい。
＜工程（Ｂ）＞
この工程では、上記工程（Ａ）で得られた、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子分散液を限外濾過装置で濃縮し、さらに希釈倍率が１０００〜２０００倍量の６０℃の温純水で洗浄を行い、残留するテトラメチルアンモニウムの濃度が１００ｐｐｍ以下となるまで洗浄を行い、少なくとも２辺が重なることなく積層した構造をなす結晶性アルミナ積層粒子分散液を得る。洗浄に用いる温純水の量は、上記の範囲から適宜選択した量で洗浄することが好ましい。
The treatment time is preferably treated under conditions appropriately selected from the above range.
<Process (B)>
In this step, the crystalline alumina laminated particle dispersion obtained in the above step (A) and having a laminated structure without overlapping at least two sides is concentrated with an ultrafiltration device, and the dilution rate is 1000 to 2000 times. Washing with a quantity of warm pure water at 60 ° C. and washing until the concentration of the remaining tetramethylammonium becomes 100 ppm or less, a crystalline alumina laminated particle dispersion having a laminated structure without overlapping at least two sides is obtained. It is preferable that the amount of warm pure water used for washing is washed in an amount appropriately selected from the above range.
残留するテトラメチルアンモニウムの濃度は、１００ｐｐｍ以下、さらには５０ｐｐｍ以下であることが好ましい。１００ｐｐｍを超えると、得られた分散液中で経時変化にともない、正方板状結晶性アルミナ微粒子が凝集する恐れがあるので好ましくない。
＜工程（ａ）＞
前記正方板状アルミナ微粒子は、アルミン酸塩を原料として用い、アルミン酸塩と水酸化ナトリウムを反応容器に入れ完全溶解したアルミン酸塩溶液を調製し、この溶液に無機酸または有機酸を添加し、温度５０〜１００℃の範囲で０．５〜２時間処理することによって、正方板状のアルミナ微粒子分散液を得る。無機酸または有機酸の添加量は、得られる分散液のｐＨが１０〜１２の範囲になるように調整する。
The concentration of the remaining tetramethylammonium is preferably 100 ppm or less, more preferably 50 ppm or less. If it exceeds 100 ppm, the square plate-like crystalline alumina fine particles may agglomerate with time in the obtained dispersion, which is not preferable.
<Process (a)>
The square plate-like alumina fine particles are prepared by using aluminate as a raw material, and preparing an aluminate solution in which aluminate and sodium hydroxide are completely dissolved in a reaction vessel, and adding an inorganic acid or an organic acid to the solution. Then, a square plate-like alumina fine particle dispersion is obtained by treating at a temperature of 50 to 100 ° C. for 0.5 to 2 hours. The amount of the inorganic acid or organic acid added is adjusted so that the pH of the resulting dispersion is in the range of 10-12.
原料として用いるアルミナとしては、アルミン酸塩を原料として用いることが好ましい。それ以外の硫酸系または硝酸系アルミナを原料に用いた場合、正方板状微粒子が得られなかったり、正方板状微粒子が得られたとしても、少なくとも２辺が重なることなく積層した構造をなす集合体が得られず、塊状化したものが得られなかったりする傾向がある。 As alumina used as a raw material, it is preferable to use an aluminate as a raw material. When other types of sulfuric acid or nitric acid-based alumina are used as raw materials, an assembly having a structure in which at least two sides do not overlap even if square plate-like fine particles are not obtained or square plate-like fine particles are obtained There is a tendency that the body cannot be obtained and the agglomerated product cannot be obtained.
無機酸としては、塩酸、硫酸、硝酸等、有機酸としてはカルボン酸、スルホン酸等を用いることが可能である。
ここで得られた分散液のｐＨは１０〜１２であり、好ましくは１０．５〜１１．５の範囲であることが好ましい。下限値未満であると、ベーマイト以外の結晶相を有するアルミナ微粒子が得られる傾向があり、本発明の正方板状のアルミナ微粒子が得られにくくなる。上限値を超えるとアルミナ自身の溶解性が高くなりアルミナ微粒子が得られなくなるので好ましくない。
As the inorganic acid, hydrochloric acid, sulfuric acid, nitric acid and the like can be used, and as the organic acid, carboxylic acid, sulfonic acid and the like can be used.
The dispersion obtained here has a pH of 10 to 12, preferably 10.5 to 11.5. If it is less than the lower limit, alumina fine particles having a crystal phase other than boehmite tend to be obtained, and the square plate-like alumina fine particles of the present invention are hardly obtained. Exceeding the upper limit is not preferable because the solubility of alumina itself increases and alumina fine particles cannot be obtained.
さらに、処理温度は５０〜１００℃で、好ましくは７０〜９０℃の範囲であることが好ましい。５０℃未満であるとベーマイト結晶相のアルミナ微粒子の粒子成長が進まないことがあり、１００℃を超えると界面濃縮効果によりベーマイト以外の結晶相が成長する傾向があるので好ましくない。ここで、界面濃縮効果とは、沸騰溶媒と気／固相の界面（液面と容器壁との境面）で溶解物がスケール状に析出する状態になることを意味する。
処理時間は、０．５〜２時間であることが好ましい。
Furthermore, the treatment temperature is 50 to 100 ° C, preferably 70 to 90 ° C. When the temperature is lower than 50 ° C., the particle growth of the alumina fine particles in the boehmite crystal phase may not proceed. Here, the interfacial concentration effect means that the dissolved substance is deposited in a scale shape at the interface between the boiling solvent and the gas / solid phase (interface between the liquid surface and the container wall).
The treatment time is preferably 0.5 to 2 hours.
この工程により得られた正方板状アルミナ微粒子分散液に、さらにアルミン酸塩溶液と無機酸または有機酸を上記と同様の操作により添加することにより、ベーマイト結晶相の結晶成長を促すことができ、得られる正方板状アルミナ微粒子の大きさを制御することが可能となる。
＜工程（ｂ）＞
この工程では、上記工程（ａ）で得られた正方板状アルミナ微粒子分散液に、吸引濾過方式により、アルミナ微粒子と母液とを分離した後、８０℃の温純水を用いてアルミナ微粒子ケーキの洗浄を行い、ケーキ中に含まれる塩化ナトリウムや吸着したナトリウムイオンを洗浄除去し、この後十分脱水し、正方板状アルミナ微粒子ケーキを得る。
ここで、洗浄に使用する温純水の量は、濾液のｐＨが１０以下程度になるまで、５０〜１００Ｌの範囲から適宜選択した条件で洗浄することが好ましい。
＜工程（ｃ）＞
この工程では、上記工程（ｂ）で得られた正方板状アルミナ微粒子ケーキを分散液化し、さらに塩基性物質を加え、大きさの揃った塩基性物質添加アルミナ微粒子分散液を得る。
By adding an aluminate solution and an inorganic acid or an organic acid to the square plate-like alumina fine particle dispersion obtained by this step in the same manner as described above, the crystal growth of the boehmite crystal phase can be promoted. It is possible to control the size of the obtained square plate-like alumina fine particles.
<Step (b)>
In this step, after separating the alumina fine particles and the mother liquor into the square plate-like alumina fine particle dispersion obtained in the step (a) by suction filtration, the alumina fine particle cake is washed with warm pure water at 80 ° C. Then, sodium chloride and adsorbed sodium ions contained in the cake are washed and removed, and then sufficiently dehydrated to obtain a square plate-like alumina fine particle cake.
Here, the amount of warm pure water used for washing is preferably washed under conditions appropriately selected from the range of 50 to 100 L until the pH of the filtrate becomes about 10 or less.
<Step (c)>
In this step, the square plate-like alumina fine particle cake obtained in the step (b) is dispersed and further added with a basic substance to obtain a basic substance-added alumina fine particle dispersion having a uniform size.
塩基性物質は、アルカリ金属、アルカリ土類金属およびアンモニウムの水に可溶な化合物から選ばれる少なくとも１種の塩基性物質を用いることが可能である。
塩基性物質としては、ナトリウム、カリウム、リチウム等の水酸化物や炭酸塩または水酸化アンモニウムや炭酸アンモニウムの無機アミンなどを用いることができる。
As the basic substance, at least one basic substance selected from alkali metal, alkaline earth metal, and ammonium water-soluble compounds can be used.
As the basic substance, hydroxides and carbonates such as sodium, potassium and lithium, inorganic amines such as ammonium hydroxide and ammonium carbonate, and the like can be used.
さらに、塩基性物質としては、強塩基性であるものが好ましく、さらにカウンターカチオンが嵩高いものであることが、正方板状粒子の結晶成長および少なくとも２辺が重ることなく積層した構造をなす結晶性アルミナ積層粒子の生成には好ましい。本発明では水酸化テトラメチルアンモニウムを用いることが好ましい。 Further, the basic substance is preferably a strongly basic substance, and the counter cation is bulky, and the crystal growth of the square plate-like particles and the structure in which at least two sides are laminated without overlapping. It is preferable for the production of crystalline alumina laminated particles. In the present invention, it is preferable to use tetramethylammonium hydroxide.
前記塩基性物質の添加量は、含有アルミナに対して３〜２５モル％の範囲で添加し、さらには５〜２０モル％の範囲であることが好ましい。範囲下限未満では粒子成長の効果か弱くなり微小な粒子しか得られなくなる可能性があり、範囲上限を超えると凝集してしまいやすくなる傾向にあるので好ましくない。 The basic substance is added in an amount of 3 to 25 mol%, more preferably 5 to 20 mol%, with respect to the contained alumina. If the amount is less than the lower limit of the range, the effect of particle growth is weakened and only fine particles may be obtained. If the upper limit of the range is exceeded, aggregation tends to occur, which is not preferable.
以下に実施例を示し、本発明を更に具体的に説明するが、本発明はこれら実施例に限定されるものではない。
[測定方法]
＜粒子の表面積測定＞
本願微粒子の表面積は、本願微粒子を凍結乾燥機で乾燥させた後、２００℃または３５０℃で３時間乾燥した試料について、表面積測定装置（ユアサアイオニクス株式会社製、マルチソーブ１２）を用いて窒素吸着法（ＢＥＴ法）により測定した。２００℃で乾燥して得られた値をＳＡ１、３５０℃で乾燥して得られた値をＳＡ２とする。単位はｍ2／ｇで表示する。
＜ｐＨ測定＞
ｐＨの測定については、２５℃のｐＨ４、７および９の標準液で更正が完了したｐＨメータ（株式会社堀場製作所社製：Ｆ２２）のガラス電極を溶液中に挿入して、ｐＨ測定を実施した。
＜塩基性物質の残留量の測定＞
塩基性物質量の測定については、ＪＩＳ Ｋ０１０２ ケルダール法・中和滴定法に準拠して行い、試料に、硫酸銅、硫酸及び硫酸カリウムを加え、有機物を分解した。次に、水酸化ナトリウムを加えてアルカリ性とした後、蒸留し、留出したアンモニアを硫酸に吸収させる)にて有機物を分解させ、露出液中のアンモニウムイオンを中和滴定法(水酸化ナトリウムにて残った硫酸を定量し、アンモニウムイオン量を算出する)にて定量した。
＜Ｘ線測定＞
正方板状結晶性アルミナの結晶相については、Ｘ線回折測定装置（ＳｍａｒｔＬａｂ, 株式会社リガク社製）を用いて、Ｘ線源；ＣｕＫα、出力；９ｋＷ、管電圧；４５ｋＶ、管電流；２００ｍＡ、スリット間隔；０．５°、測定角度２θ；１０°〜７０°、走査速度；１０°／分の条件により、Ｘ線回折測定で確認した。
[実施例１]
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
[Measuring method]
<Measurement of particle surface area>
The surface area of the fine particles of the present application is determined by nitrogen adsorption using a surface area measuring device (manufactured by Yuasa Ionics Co., Ltd., Multisorb 12) on a sample dried at 200 ° C. or 350 ° C. for 3 hours after drying the fine particles of the present application with a freeze dryer. Measured by the method (BET method). The value obtained by drying at 200 ° C. is SA1, and the value obtained by drying at 350 ° C. is SA2. The unit is expressed in m 2 / g.
<PH measurement>
Regarding the pH measurement, a glass electrode of a pH meter (H22 manufactured by Horiba, Ltd .: F22) whose correction was completed with standard solutions of pH 4, 7, and 9 at 25 ° C. was inserted into the solution, and the pH measurement was performed. .
<Measurement of residual amount of basic substance>
Measurement of the basic substance amount was performed in accordance with JIS K0102 Kjeldahl method / neutralization titration method, and copper sulfate, sulfuric acid and potassium sulfate were added to the sample to decompose the organic matter. Next, after adding sodium hydroxide to make it alkaline, the organic substance is decomposed by distilling and absorbing the distilled ammonia into sulfuric acid), and ammonium ions in the exposed solution are neutralized by titration (to sodium hydroxide). The remaining sulfuric acid was quantified and the amount of ammonium ions was calculated).
<X-ray measurement>
For the crystal phase of the tetragonal plate-like crystalline alumina, using an X-ray diffraction measurement apparatus (SmartLab, manufactured by Rigaku Corporation), X-ray source: CuKα, output: 9 kW, tube voltage: 45 kV, tube current: 200 mA, Slit interval: 0.5 °, measurement angle 2θ: 10 ° to 70 °, scanning speed: 10 ° / min.
[Example 1]
＜結晶性アルミナ積層粒子（１）分散液の製造方法＞
＜工程（ａ）＞ １００Ｌのスチームジャケット付タンクへ純水３８．７４３ｋｇを張り込み、これに濃度４８質量％の水酸化ナトリウム溶液（関東化学株式会社製、特級）０．８１５ｋｇを撹拌しながら加えた。
<Method for Producing Crystalline Alumina Laminated Particle (1) Dispersion>
<Step (a)> 38.743 kg of pure water was put into a 100 L steam jacketed tank, and 0.815 kg of a sodium hydroxide solution having a concentration of 48% by mass (manufactured by Kanto Chemical Co., Ltd., special grade) was added thereto with stirring. .
この溶液に、アルミン酸ナトリウム（関東化学株式会社製、鹿１級、アルミナ換算３９質量％）２．７４０ｋｇを撹拌しながら溶解した。
さらに、この溶液を撹拌しながら８０℃へ昇温し１時間保持することで、完全溶解した希釈アルミン酸ナトリウム水溶液４２．２９８ｋｇを得た。
In this solution, 2.740 kg of sodium aluminate (manufactured by Kanto Chemical Co., Inc., deer grade 1, 39% by mass in terms of alumina) was dissolved with stirring.
Furthermore, this solution was heated to 80 ° C. with stirring and held for 1 hour to obtain 42.298 kg of a completely dissolved aqueous sodium aluminate solution.
スチームジャケット付１０Ｌタンクに純水６．２６９ｋｇを張り込み、これに３５質量%の塩酸水溶液（関東化学株式会社製、特級）０．４５３ｋｇを撹拌しながら混合し、さらに８０℃まで加温し希釈塩酸６．７２２ｋｇを得た。 6.269 kg of pure water was put into a 10 L tank with a steam jacket, and 0.453 kg of 35% by weight hydrochloric acid aqueous solution (manufactured by Kanto Chemical Co., Ltd., special grade) was mixed with stirring, and further heated to 80 ° C. to dilute hydrochloric acid 6.722 kg was obtained.
この希釈アルミン酸ナトリウム水溶液を８０℃に保ったまま、撹拌しながら前記希釈塩酸水溶液を全量添加混合し、さらに撹拌しながら８０℃で１時間保持して、ｐＨ１１．５の正方板状アルミナ微粒子（１ａ）分散液４９．０２０ｋｇを得た。
＜工程（ｂ）＞ このアルミナ微粒子（１ａ）分散液を脱気式のプレートフィルターにて脱水し、母液を分離した後、プレートフィルター状に得られたアルミナ微粒子ケーキへ減圧下で８０℃温純水５０〜１００Ｌを通水し、アルミナ微粒子ケーキに含まれる塩化ナトリウム及び吸着したナトリウムを洗浄除去した。この後十分に減圧下で脱水することでアルミナ微粒子（１ｂ）ケーキ６．６６７ｋｇを得た。
＜工程（ｃ）＞ このアルミナ微粒子（１ｂ）ケーキ６．６６７ｋｇへ純水１２．９８３ｋｇを加え、十分に撹拌して分散させアルミナ微粒子希釈分散液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）を加え、塩基性物質添加アルミナ微粒子（１ｃ）分散液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加アルミナ微粒子（１ｃ）分散液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、３０〜５０ｎｍ正方形で、厚みが３〜５ｎｍの大きさの１次結晶粒子５〜１０個が、少なくとも２辺が重なることなく積層した構造に凝集した１００〜２００ｎｍの大きさの２次粒子を形成する結晶性アルミナ積層粒子（１Ａ）分散液を得た。
＜工程（Ｂ）＞ この結晶性アルミナ積層粒子（１Ａ）分散液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナの結晶性アルミナ積層粒子（１）分散液２０．０００ｋｇを得た。
While maintaining this dilute sodium aluminate aqueous solution at 80 ° C., the whole amount of the dilute hydrochloric acid aqueous solution was added and mixed while stirring, and further kept at 80 ° C. with stirring for 1 hour to obtain a square plate-like alumina fine particle having a pH of 11.5 ( 1a) 49.020 kg of dispersion was obtained.
<Step (b)> After the alumina fine particle (1a) dispersion was dehydrated with a degassing plate filter and the mother liquor was separated, the alumina fine particle cake obtained in the form of a plate filter was heated to 80 ° C. hot pure water 50 under reduced pressure. ˜100 L was passed through to wash away sodium chloride and adsorbed sodium contained in the alumina fine particle cake. Thereafter, it was sufficiently dehydrated under reduced pressure to obtain 6.667 kg of alumina fine particle (1b) cake.
<Step (c)> To 6.667 kg of the alumina fine particle (1b) cake, 12.983 kg of pure water was added and dispersed by sufficiently stirring to obtain a diluted alumina fine particle dispersion of 19.650 kg. To this, tetramethylammonium hydroxide was added. An aqueous solution (manufactured by Kanto Chemical Co., Inc., concentration 27% by mass) was added to obtain 20.000 kg of a basic substance-added alumina fine particle (1c) dispersion.
<Step (A)> This basic substance-added alumina fine particle (1c) dispersion is put into an autoclave reactor, heated to 150 ° C. with stirring, reacted for 24 hours under pressure, a 30 to 50 nm square, and a thickness of 3 Crystalline alumina laminated particles (1A) that form secondary particles with a size of 100 to 200 nm in which 5 to 10 primary crystal particles with a size of -5 nm are aggregated in a laminated structure without overlapping at least two sides A dispersion was obtained.
<Step (B)> This crystalline alumina laminated particle (1A) dispersion is put in an ultrafiltration device, washed with warm pure water at a dilution rate of 1000 to 2000 times 60 ° C., and the residual nitrogen concentration is changed to tetramethyl. Washing was performed until the concentration in terms of ammonium was (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of a 5 mass% alumina crystalline alumina laminated particle (1) dispersion.
結晶性アルミナ積層粒子（１）について、性状を表１に示す。
[実施例２]
Table 1 shows the properties of the crystalline alumina laminated particles (1).
[Example 2]
＜結晶性アルミナ積層粒子（２）分散液の製造方法＞
＜工程（ａ）＞ １００Ｌのスチームジャケット付タンクへ純水３８．７４３ｋｇを張り込み、これに濃度４８質量％の水酸化ナトリウム溶液（関東化学株式会社製、特級）０．８１５ｋｇを撹拌しながら加えた。
<Method for producing crystalline alumina laminated particle (2) dispersion>
<Step (a)> 38.743 kg of pure water was put into a 100 L steam jacketed tank, and 0.815 kg of a sodium hydroxide solution having a concentration of 48% by mass (manufactured by Kanto Chemical Co., Ltd., special grade) was added thereto with stirring. .
この溶液に、アルミン酸ナトリウム（関東化学株式会社製、鹿１級、アルミナ換算３９質量％）２．７４０ｋｇを撹拌しながら溶解した。
さらに、この溶液を撹拌しながら８０℃へ昇温し１時間保持することで、完全溶解した希釈アルミン酸ナトリウム水溶液４２．２９８ｋｇを得た。
In this solution, 2.740 kg of sodium aluminate (manufactured by Kanto Chemical Co., Inc., deer grade 1, 39% by mass in terms of alumina) was dissolved with stirring.
Furthermore, this solution was heated to 80 ° C. with stirring and held for 1 hour to obtain 42.298 kg of a completely dissolved aqueous sodium aluminate solution.
スチームジャケット付１０Ｌタンクに純水６．３１６ｋｇを張り込み、これに７０質量%の硝酸水溶液（関東化学株式会社製、特級）０．４０６ｋｇを撹拌しながら混合し、さらに８０℃まで加温し希釈硝酸６．７２２ｋｇを得た。 6.316 kg of pure water was put into a 10 L tank with a steam jacket, and 0.406 kg of 70% by mass nitric acid aqueous solution (manufactured by Kanto Chemical Co., Ltd., special grade) was mixed with stirring, and further heated to 80 ° C. to dilute nitric acid 6.722 kg was obtained.
この希釈アルミン酸ナトリウム水溶液を８０℃に保ったまま、撹拌しながら前記希釈硝酸水溶液を全量添加混合し、さらに撹拌しながら８０℃で１時間保持して、ｐＨ１１．５の正方板状アルミナ微粒子（２ａ）分散液４９．０２０ｋｇを得た。
＜工程（ｂ）＞ このアルミナ微粒子（２ａ）分散液を脱気式のプレートフィルターにて脱水し、母液を分離した後、プレートフィルター状に得られたアルミナ微粒子ケーキへ減圧下で８０℃温純水５０〜１００Ｌを通水し、アルミナ微粒子ケーキに含まれる硝酸ナトリウム及び吸着したナトリウムを洗浄除去し、この後十分に減圧下で脱水することでアルミナ微粒子（２ｂ）ケーキ６．６６７ｋｇを得る。
＜工程（ｃ）＞ このアルミナ微粒子（２ｂ）ケーキ６．６６７ｋｇへ純水１２．９８３ｋｇを加え、十分に撹拌して分散させアルミナ微粒子希釈分散液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）を加え、塩基性物質添加アルミナ微粒子（２ｃ）分散液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加アルミナ微粒子（２ｃ）分散液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、３０〜４０ｎｍ正方形で、厚みが３〜４ｎｍの大きさの１次結晶粒子５〜１０個が、少なくとも２辺が重なることなく積層した構造に凝集した１００〜２００ｎｍの大きさの２次粒子を形成する結晶性アルミナ積層粒子（２Ａ）分散液を得た。
＜工程（Ｂ）＞ この結晶性アルミナ積層粒子（２Ａ）分散液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナの結晶性アルミナ積層粒子（２）分散液２０．０００ｋｇを得た。
While maintaining this dilute sodium aluminate aqueous solution at 80 ° C., the whole amount of the dilute nitric acid aqueous solution was added and mixed while stirring, and further kept at 80 ° C. with stirring for 1 hour to obtain a square plate-like alumina fine particle having a pH of 11.5 ( 2a) 49.020 kg of dispersion was obtained.
<Step (b)> After the alumina fine particle (2a) dispersion was dehydrated with a degassing plate filter and the mother liquor was separated, the alumina fine particle cake obtained in the form of a plate filter was heated to 80 ° C. hot pure water 50 under reduced pressure. ˜100 L of water is passed through to wash and remove sodium nitrate and adsorbed sodium contained in the alumina fine particle cake, and then sufficiently dehydrated under reduced pressure to obtain 6.667 kg of alumina fine particle (2b) cake.
<Step (c)> To 6.667 kg of the alumina fine particle (2b) cake, 12.983 kg of pure water was added and dispersed by sufficiently stirring to obtain an alumina fine particle diluted dispersion liquid of 19.650 kg, to which tetramethylammonium hydroxide was added. An aqueous solution (manufactured by Kanto Chemical Co., Inc., concentration 27 mass%) was added to obtain 20.000 kg of a basic substance-added alumina fine particle (2c) dispersion.
<Step (A)> This basic substance-added alumina fine particle (2c) dispersion is put into an autoclave reactor, heated to 150 ° C. with stirring, and reacted for 24 hours under pressure, a 30 to 40 nm square having a thickness of 3 Crystalline alumina laminated particles (2A) that form secondary particles with a size of 100 to 200 nm in which 5 to 10 primary crystal particles with a size of ˜4 nm are aggregated in a laminated structure without overlapping at least two sides A dispersion was obtained.
<Step (B)> This crystalline alumina laminated particle (2A) dispersion is placed in an ultrafiltration device, washed with 60 ° C. hot pure water having a dilution rate of 1000 to 2000 times, and the residual nitrogen concentration is changed to tetramethyl. Washing was performed until the concentration in terms of ammonium reached (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of 5 mass% alumina crystalline alumina laminated particle (2) dispersion.
結晶性アルミナ積層粒子（２）について、性状を表１に示す。
[実施例３]
Table 1 shows the properties of the crystalline alumina laminated particles (2).
[Example 3]
＜結晶性アルミナ積層粒子（３）分散液の製造方法＞
＜工程（ａ）＞ １００Ｌのスチームジャケット付タンクへ純水３８．７４３ｋｇを張り込み、これに濃度４８質量％の水酸化ナトリウム溶液（関東化学株式会社製、特級）０．８１５ｋｇを撹拌しながら加えた。
<Method for producing crystalline alumina laminated particle (3) dispersion>
<Step (a)> 38.743 kg of pure water was put into a 100 L steam jacketed tank, and 0.815 kg of a sodium hydroxide solution having a concentration of 48% by mass (manufactured by Kanto Chemical Co., Ltd., special grade) was added thereto with stirring. .
この溶液に、アルミン酸ナトリウム（関東化学株式会社製、鹿１級、アルミナ換算３９質量％）２．７４０ｋｇを撹拌しながら溶解した。
さらに、この溶液を撹拌しながら８０℃へ昇温し１時間保持することで、完全溶解した希釈アルミン酸ナトリウム水溶液４２．２９８ｋｇを得た。
In this solution, 2.740 kg of sodium aluminate (manufactured by Kanto Chemical Co., Inc., deer grade 1, 39% by mass in terms of alumina) was dissolved with stirring.
Furthermore, this solution was heated to 80 ° C. with stirring and held for 1 hour to obtain 42.298 kg of a completely dissolved aqueous sodium aluminate solution.
スチームジャケット付１０Ｌタンクに純水６．４９３ｋｇを張り込み、これに９６質量%の硫酸水溶液（関東化学株式会社製、特級）０．２２９ｋｇを撹拌しながら混合し、さらに８０℃まで加温し希釈硫酸６．７２２ｋｇを得た。 6.493 kg of pure water was put into a 10 L tank with a steam jacket, and 0.229 kg of 96% by weight sulfuric acid aqueous solution (manufactured by Kanto Chemical Co., Ltd., special grade) was mixed with stirring, and further heated to 80 ° C. to dilute sulfuric acid 6.722 kg was obtained.
この希釈アルミン酸ナトリウム水溶液を８０℃に保ったまま、撹拌しながら前記希釈硫酸水溶液を全量添加混合し、さらに撹拌しながら８０℃で１時間保持して、ｐＨ１１．５の正方板状アルミナ微粒子（３ａ）分散液４９．０２０ｋｇを得た。
＜工程（ｂ）＞ この正方板状アルミナ微粒子（３ａ）分散液を脱気式のプレートフィルターにて脱水し、母液を分離した後、プレートフィルター状に得られた調合ヒドロゲルケーキへ減圧下で８０℃温純水５０〜１００Ｌを通水し、調合ヒドロゲルケーキに含まれる硫酸ナトリウム及び吸着したナトリウムを洗浄除去し、この後十分に減圧下で脱水することでアルミナ微粒子（３ｂ）ケーキ６．６６７ｋｇを得る。
＜工程（ｃ）＞ このアルミナ微粒子（３ｂ）ケーキ６．６６７ｋｇへ純水１２．９８３ｋｇを加え、十分に撹拌して分散させアルミナヒドロゲル希釈分散液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）を加え、塩基性物質添加アルミナ微粒子（３ｃ）分散液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加アルミナ微粒子（３ｃ）分散液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、２０〜６０ｎｍ正方で、厚みが２〜６ｎｍの大きさの１次結晶粒子５〜１０個が、少なくとも２辺が重なることなく積層した構造に凝集した５０〜３００ｎｍの大きさの２次粒子を形成する結晶性アルミナ積層粒子（３Ａ）分散液を得た。
＜工程（Ｂ）＞ この結晶性アルミナ積層粒子（３Ａ）分散液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナの結晶性アルミナ積層粒子（３）分散液２０．０００ｋｇを得た。
While maintaining this dilute sodium aluminate aqueous solution at 80 ° C., all of the dilute sulfuric acid aqueous solution was added and mixed while stirring, and further kept at 80 ° C. for 1 hour with stirring to obtain a square plate-like alumina fine particle having a pH of 11.5 ( 3a) 49.020 kg of dispersion was obtained.
<Step (b)> This square plate-like alumina fine particle (3a) dispersion was dehydrated with a degassing plate filter, and the mother liquor was separated, and then the mixture hydrogel cake obtained in a plate filter shape was subjected to 80 under reduced pressure. 50-100 L of warm pure water is passed through to wash away sodium sulfate and adsorbed sodium contained in the prepared hydrogel cake, and then sufficiently dehydrated under reduced pressure to obtain 6.667 kg of alumina fine particle (3b) cake.
<Step (c)> To 6.667 kg of the alumina fine particle (3b) cake, 12.983 kg of pure water was added and dispersed by sufficiently stirring to obtain an alumina hydrogel diluted dispersion liquid of 19.650 kg. To this, tetramethylammonium hydroxide was added. An aqueous solution (manufactured by Kanto Chemical Co., Inc., concentration 27% by mass) was added to obtain 20.000 kg of a basic substance-added alumina fine particle (3c) dispersion.
<Step (A)> This basic substance-added alumina fine particle (3c) dispersion is placed in an autoclave reactor, heated to 150 ° C. with stirring, reacted for 24 hours under pressure, 20 to 60 nm square and 2 in thickness. Crystalline alumina laminated particles (3A) forming 5 to 10 nm primary crystal particles having a size of 50 to 300 nm aggregated in a structure in which 5 to 10 primary crystal particles are laminated without overlapping at least two sides A dispersion was obtained.
<Step (B)> This crystalline alumina laminated particle (3A) dispersion is put into an ultrafiltration device, washed with warm pure water at a dilution rate of 1000 to 2000 times 60 ° C., and the residual nitrogen concentration is changed to tetramethyl. Washing was performed until the concentration in terms of ammonium reached (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of 5 mass% alumina crystalline alumina laminated particle (3) dispersion.
結晶性アルミナ積層粒子（３）について、性状を表１に示す。
[実施例４]
Table 1 shows the properties of the crystalline alumina laminated particles (3).
[Example 4]
＜結晶性アルミナ積層粒子（４）分散液の製造方法＞
＜工程（ｄ）＞ 市販の結晶性アルミナ微粒子パウダー(Ｓａｓｏｌ社製、ＤＩＳＰＥＲＡＬ−Ｐ２、濃度７２質量％)０．５５６ｋｇへ純水１９．０９４ｋｇを加え、十分に撹拌して分散させアルミナヒドロゲル希釈分散液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）を加え、塩基性物質添加結晶性アルミナ微粒子（４ｃ）分散液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加アルミナ微粒子（４ｃ）分散液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、２０〜５０ｎｍ正方で、厚みが４〜８ｎｍの大きさの１次結晶粒子５〜１０個が、少なくとも２辺が重なることなく積層した構造に凝集した５０〜３００ｎｍの大きさの２次粒子を形成する結晶性アルミナ積層粒子（４Ａ）分散液を得た。
＜工程（Ｂ）＞ この結晶性アルミナ積層粒子（４Ａ）分散液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナの結晶性アルミナ積層粒子（４）分散液２０．０００ｋｇを得た。
<Method for Producing Crystalline Alumina Laminated Particle (4) Dispersion>
<Step (d)> Commercially available crystalline alumina fine particle powder (manufactured by Sasol, DISPERAL-P2, concentration 72% by mass) 0.556 kg of pure water 19.094 kg is added and sufficiently stirred and dispersed to dilute and disperse the alumina hydrogel. The liquid was made 19.650 kg, and a tetramethylammonium hydroxide aqueous solution (manufactured by Kanto Chemical Co., Inc., concentration 27 mass%) was added thereto to obtain 20.000 kg of a basic substance-added crystalline alumina fine particle (4c) dispersion.
<Step (A)> This basic substance-added alumina fine particle (4c) dispersion is placed in an autoclave reactor, heated to 150 ° C. with stirring, reacted for 24 hours under pressure, 20 to 50 nm square and 4 in thickness. Crystalline alumina laminated particles (4A) forming 5 to 10 nm primary crystal particles having a size of 50 to 300 nm aggregated in a structure in which 5 to 10 primary crystal particles having a size of 8 nm are laminated without overlapping at least two sides A dispersion was obtained.
<Step (B)> This crystalline alumina laminated particle (4A) dispersion is put in an ultrafiltration device, washed with warm pure water at a dilution rate of 1000 to 2000 times 60 ° C., and the residual nitrogen concentration is changed to tetramethyl. Washing was performed until the concentration in terms of ammonium reached (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of a 5 mass% alumina crystalline alumina laminated particle (4) dispersion.
結晶性アルミナ積層粒子（４）について、性状を表１に示す。
［比較例１］
＜塊状結晶性アルミナ粒子（Ｒ１）分散液の製造方法＞
＜工程（ａ）＞ ５０Ｌのスチームジャケット付タンクへ純水２６．３４５ｋｇを張り込み、これに濃度４８質量％の水酸化ナトリウム溶液（関東化学株式会社製、特級）０．５５４ｋｇを撹拌しながら加えた。
Table 1 shows the properties of the crystalline alumina laminated particles (4).
[Comparative Example 1]
<Method for Producing Bulk Crystalline Alumina Particle (R1) Dispersion>
<Step (a)> 26.345 kg of pure water was put into a 50 L tank with a steam jacket, and 0.554 kg of a sodium hydroxide solution having a concentration of 48% by mass (manufactured by Kanto Chemical Co., Ltd., special grade) was added thereto with stirring. .
この溶液に、アルミン酸ナトリウム（関東化学株式会社製、鹿１級、アルミナ換算３９質量％）１．８６３ｋｇを撹拌しながら溶解した。
さらに、この溶液を撹拌しながら８０℃へ昇温し１時間保持することで、完全溶解した希釈アルミン酸ナトリウム水溶液２８．７６２ｋｇを得た。
In this solution, 1.863 kg of sodium aluminate (manufactured by Kanto Chemical Co., Inc., deer grade 1, 39% by mass in terms of alumina) was dissolved with stirring.
Furthermore, this solution was heated to 80 ° C. with stirring and held for 1 hour to obtain 28.762 kg of a completely dissolved sodium aluminate aqueous solution.
スチームジャケット付１０Ｌタンクに純水４．３２１ｋｇを張り込み、これに純度９８質量%の塩化アルミニウム・九水和物（関東化学株式会社製、鹿特級）０．２５０ｋｇを撹拌しながら混合し、さらに８０℃まで加温し希釈塩化アルミニウム水溶液４．５７１ｋｇを得た。 4. 321 kg of pure water was put into a 10 L tank with a steam jacket, and 0.250 kg of 98% by mass aluminum chloride nonahydrate (manufactured by Kanto Chemical Co., Ltd., deer special grade) was mixed with stirring, and further 80 The mixture was heated to 0 ° C. to obtain 4.571 kg of a diluted aluminum chloride aqueous solution.
この希釈アルミン酸ナトリウム水溶液を８０℃に保ったまま、撹拌しながら前記希釈塩化アルミニウム水溶液を全量添加混合し、さらに撹拌しながら８０℃で１時間保持して、ｐＨ１１．５のアルミナ微粒子（Ｒ１ａ）分散液３３．３３３ｋｇを得た。
＜工程（ｂ）＞ このアルミナ微粒子（Ｒ１ａ）分散液を脱気式のプレートフィルターにて脱水し、母液を分離した後、プレートフィルター状に得られたアルミナ微粒子ケーキへ減圧下で８０℃温純水５０〜１００Ｌを通水し、アルミナ微粒子ケーキに含まれる塩化ナトリウム及び吸着したナトリウムを洗浄除去し、この後十分に減圧下で脱水することでアルミナ微粒子（Ｒ１ｂ）ケーキ６．６６７ｋｇを得た。
＜工程（ｃ）＞ このアルミナ微粒子（Ｒ１ｂ）ケーキ６．６６７ｋｇへ純水１２．９８３ｋｇを加え、十分に撹拌して分散させアルミナ微粒子希釈分散液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）０．３５０ｋｇを加え、塩基性物質添加アルミナ微粒子（Ｒ１ｃ）分散液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加アルミナ微粒子（Ｒ１ｃ）分散液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、４０〜８０ｎｍ正方で、厚みが４〜８ｎｍの大きさの１次結晶粒子が５〜１０個が塊状に凝集した１５０〜４００ｎｍの大きさの２次粒子を形成する塊状結晶性アルミナ粒子（Ｒ１Ａ）分散液を得た。
＜工程（Ｂ）＞ この塊状結晶性アルミナ粒子（Ｒ１Ａ）分散液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナの結晶性アルミナ粒子（Ｒ１）分散液２０．０００ｋｇを得た。得られた結晶性アルミナ微粒子自身が、正方板状として整ったモノが少ない状態であった。
While maintaining this dilute sodium aluminate aqueous solution at 80 ° C., the entire amount of the dilute aluminum chloride aqueous solution was added and mixed while stirring, and further maintained at 80 ° C. with stirring for 1 hour to obtain alumina fine particles (R1a) having a pH of 11.5. 33.333 kg of dispersion was obtained.
<Step (b)> After the alumina fine particle (R1a) dispersion was dehydrated with a degassing plate filter and the mother liquor was separated, the alumina fine particle cake obtained in the shape of a plate filter was heated to 80 ° C. hot pure water 50 After passing through 100 L, sodium chloride and adsorbed sodium contained in the alumina fine particle cake were washed and removed, and then sufficiently dehydrated under reduced pressure to obtain 6.667 kg of alumina fine particle (R1b) cake.
<Step (c)> To 6.667 kg of the alumina fine particle (R1b) cake, 12.983 kg of pure water is added and dispersed by sufficiently stirring to obtain an alumina fine particle diluted dispersion liquid of 19.650 kg. To this, tetramethylammonium hydroxide is added. 0.350 kg of an aqueous solution (manufactured by Kanto Chemical Co., Inc., concentration 27% by mass) was added to obtain 20.000 kg of a basic substance-added alumina fine particle (R1c) dispersion.
<Step (A)> This basic substance-added alumina fine particle (R1c) dispersion is placed in an autoclave reactor, heated to 150 ° C. with stirring, and allowed to react for 24 hours under pressure, 40 to 80 nm square and 4 in thickness. A bulk crystalline alumina particle (R1A) dispersion was obtained which formed secondary particles having a size of 150 to 400 nm in which 5 to 10 primary crystal particles having a size of ˜8 nm were aggregated in a bulk shape.
<Step (B)> This bulk crystalline alumina particle (R1A) dispersion is put into an ultrafiltration apparatus, washed with warm pure water at a dilution rate of 1000 to 2000 times 60 ° C., and the residual nitrogen concentration is changed to tetramethyl. Washing was performed until the concentration in terms of ammonium was (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of a 5 mass% alumina crystalline alumina particle (R1) dispersion. The obtained crystalline alumina fine particles themselves were in a state of few things arranged as a square plate.
塊状結晶性アルミナ粒子（Ｒ１）について、性状を表１に示す。
［比較例２］
＜塊状結晶性アルミナ粒子（Ｒ２）分散液の製造方法＞
＜工程（ａ）＞ ５０Ｌのスチームジャケット付タンクへ純水２６．３４５ｋｇを張り込み、これに濃度４８質量％の水酸化ナトリウム溶液（関東化学株式会社製、特級）０．５５４ｋｇを撹拌しながら加えた。
Table 1 shows the properties of the bulk crystalline alumina particles (R1).
[Comparative Example 2]
<Method for Producing Bulk Crystalline Alumina Particle (R2) Dispersion>
<Step (a)> 26.345 kg of pure water was put into a 50 L tank with a steam jacket, and 0.554 kg of a sodium hydroxide solution having a concentration of 48% by mass (manufactured by Kanto Chemical Co., Ltd., special grade) was added thereto with stirring. .
この溶液に、アルミン酸ナトリウム（関東化学株式会社製、鹿１級、アルミナ換算３９質量％）１．８６３ｋｇを撹拌しながら溶解した。
さらに、この溶液を撹拌しながら８０℃へ昇温し１時間保持することで、完全溶解した希釈アルミン酸ナトリウム水溶液２８．７６２ｋｇを得た。
In this solution, 1.863 kg of sodium aluminate (manufactured by Kanto Chemical Co., Inc., deer grade 1, 39% by mass in terms of alumina) was dissolved with stirring.
Furthermore, this solution was heated to 80 ° C. with stirring and held for 1 hour to obtain 28.762 kg of a completely dissolved sodium aluminate aqueous solution.
スチームジャケット付１０Ｌタンクに純水４．１８２ｋｇを張り込み、これに９８質量%の硝酸アルミニウム・九水和物（関東化学株式会社製、鹿特級）０．３８９ｋｇを撹拌しながら混合し、さらに８０℃まで加温し希釈硝酸アルミニウム水溶液４．５７１ｋｇを得た。 4.182 kg of pure water was put into a 10 L tank with a steam jacket, and 0.389 kg of 98 mass% aluminum nitrate nonahydrate (manufactured by Kanto Chemical Co., Ltd., deer special grade) was mixed with stirring, and further 80 ° C. To obtain 4.571 kg of diluted aluminum nitrate aqueous solution.
この希釈アルミン酸ナトリウム水溶液を８０℃に保ったまま、撹拌しながら前記希釈硝酸アルミニウム水溶液を全量添加混合し、さらに撹拌しながら８０℃で１時間保持して、ｐＨ１１．５のアルミナ微粒子（Ｒ２ａ）分散液３３．３３３ｋｇを得た。
＜工程（ｂ）＞ このアルミナ微粒子（Ｒ２ａ）分散液を脱気式のプレートフィルターにて脱水し、母液を分離した後、プレートフィルター状に得られたアルミナ微粒子ケーキへ減圧下で８０℃の温純水５０〜１００Ｌを通水し、アルミナ微粒子ケーキに含まれる硝酸ナトリウム及び吸着したナトリウムを洗浄除去し、この後十分に減圧下で脱水することでアルミナ微粒子（Ｒ２ｂ）ケーキ６．６６７ｋｇを得る。
＜工程（ｃ）＞ このアルミナ微粒子（Ｒ２ｂ）ケーキ６．６６７ｋｇへ純水１２．９８３ｋｇを加え、十分に撹拌して分散させアルミナ微粒子希釈分散液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）０．３５０ｋｇを加え、塩基性物質添加アルミナ微粒子（Ｒ２ｃ）分散液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加アルミナ微粒子（Ｒ２ｃ）分散液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、４０〜６０ｎｍ正方で、厚みが４〜６ｎｍの大きさの１次結晶粒子が５〜１０個が塊状に凝集した１５０〜３００ｎｍの大きさの２次粒子を形成する塊状結晶性アルミナ粒子（Ｒ２Ａ）分散液を得た。
＜工程（Ｂ）＞ この塊状結晶性アルミナ粒子（Ｒ２Ａ）分散液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナの塊状結晶性アルミナ粒子（Ｒ２）分散液２０．０００ｋｇを得た。得られたアルミナ粒子は正方板状ではなく、直方体状でありさらに角が丸みを帯びた形状であった。
While maintaining this diluted sodium aluminate aqueous solution at 80 ° C., the whole amount of the diluted aluminum nitrate aqueous solution was added and mixed while stirring, and further maintained at 80 ° C. with stirring for 1 hour to obtain alumina fine particles (R2a) having a pH of 11.5. 33.333 kg of dispersion was obtained.
<Step (b)> The alumina fine particle (R2a) dispersion is dehydrated with a degassing plate filter, and the mother liquor is separated. Then, the alumina fine particle cake obtained in the form of a plate filter is heated to 80 ° C. under reduced pressure at 80 ° C. 50 to 100 L are passed through, and sodium nitrate and adsorbed sodium contained in the alumina fine particle cake are washed and removed, and then sufficiently dehydrated under reduced pressure to obtain 6.667 kg of alumina fine particle (R2b) cake.
<Step (c)> To 6.667 kg of the alumina fine particle (R2b) cake, 12.983 kg of pure water was added and dispersed by sufficiently stirring to obtain a diluted alumina fine particle dispersion of 19.650 kg, and tetramethylammonium hydroxide was added thereto. 0.350 kg of an aqueous solution (manufactured by Kanto Chemical Co., Inc., concentration 27 mass%) was added to obtain 20.000 kg of a basic substance-added alumina fine particle (R2c) dispersion.
<Step (A)> This basic substance-added alumina fine particle (R2c) dispersion is placed in an autoclave reactor, heated to 150 ° C. with stirring, and allowed to react for 24 hours under pressure, 40 to 60 nm square and 4 in thickness. A bulk crystalline alumina particle (R2A) dispersion was obtained which formed secondary particles with a size of 150 to 300 nm in which 5 to 10 primary crystal particles with a size of ˜6 nm were aggregated in a bulk shape.
<Step (B)> This bulk crystalline alumina particle (R2A) dispersion is put into an ultrafiltration apparatus, washed with warm pure water at a dilution rate of 1000 to 2000 times 60 ° C., and the residual nitrogen concentration is changed to tetramethyl. Washing was performed until the concentration in terms of ammonium reached (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of a mass crystalline alumina particle (R2) dispersion of 5% by mass alumina. The obtained alumina particles were not a square plate shape but a rectangular parallelepiped shape and a shape with rounded corners.
塊状結晶性アルミナ粒子（Ｒ２）について性状を表１に示す。
［比較例３］
＜塊状結晶性アルミナ粒子（Ｒ３）分散液の製造方法＞
＜工程（ａ）＞ ５０Ｌのスチームジャケット付タンクへ純水２６．３４５ｋｇを張り込み、これに濃度４８質量％の水酸化ナトリウム溶液（関東化学株式会社製、特級）０．５５４ｋｇを撹拌しながら加えた。
Table 1 shows the properties of the bulk crystalline alumina particles (R2).
[Comparative Example 3]
<Method for Producing Bulk Crystalline Alumina Particle (R3) Dispersion>
<Step (a)> 26.345 kg of pure water was put into a 50 L tank with a steam jacket, and 0.554 kg of a sodium hydroxide solution having a concentration of 48% by mass (manufactured by Kanto Chemical Co., Ltd., special grade) was added thereto with stirring. .
この溶液に、アルミン酸ナトリウム（関東化学株式会社製、鹿１級、アルミナ換算３９質量％）１．８６３ｋｇを撹拌しながら溶解した。
さらに、この溶液を撹拌しながら８０℃へ昇温し１時間保持することで、完全溶解した希釈アルミン酸ナトリウム水溶液２８．７６２ｋｇを得た。
In this solution, 1.863 kg of sodium aluminate (manufactured by Kanto Chemical Co., Inc., deer grade 1, 39% by mass in terms of alumina) was dissolved with stirring.
Furthermore, this solution was heated to 80 ° C. with stirring and held for 1 hour to obtain 28.762 kg of a completely dissolved sodium aluminate aqueous solution.
スチームジャケット付１０Ｌタンクに純水３．９８１ｋｇを張り込み、これに５７質量％の硫酸アルミニウム・十四〜十八水和物（関東化学株式会社製、鹿特級）０．５９０ｋｇを撹拌しながら混合し、さらに８０℃まで加温し希釈硫酸アルミニウム水溶液４．５７１ｋｇを得た。 3.981 kg of pure water was put into a 10 L tank with a steam jacket, and 0.590 kg of 57% by mass of aluminum sulfate 14 to 18 hydrate (manufactured by Kanto Chemical Co., Ltd., deer special grade) was mixed with stirring. The mixture was further heated to 80 ° C. to obtain 4.571 kg of a diluted aluminum sulfate aqueous solution.
この希釈アルミン酸ナトリウム水溶液を８０℃に保ったまま、撹拌しながら前記希釈硫酸アルミニウム水溶液を全量添加混合し、さらに撹拌しながら８０℃で１時間保持して、ｐＨ１１．５のアルミナ微粒子（Ｒ３ａ）分散液３３．３３３ｋｇを得た。
＜工程（ｂ）＞ このアルミナ微粒子（Ｒ３ａ）分散液を脱気式のプレートフィルターにて脱水し、母液を分離した後、プレートフィルター状に得られたアルミナ微粒子ケーキへ減圧下で８０℃の温純水５０〜１００Ｌを通水し、アルミナ微粒子ケーキに含まれる硫酸ナトリウム及び吸着したナトリウムを洗浄除去し、この後十分に減圧下で脱水することでアルミナ微粒子（Ｒ３ｂ）ケーキ６．６６７ｋｇを得る。
＜工程（ｃ）＞ このアルミナ微粒子（Ｒ３ｂ）ケーキ６．６６７ｋｇへ純水１２．９８３ｋｇを加え、十分に撹拌して分散させアルミナヒドロゲル希釈分散液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）０．３５０ｋｇを加え、塩基性物質添加アルミナ微粒子（Ｒ３ｃ）分散液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加アルミナ微粒子（Ｒ３ｃ）分散液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、３０〜７０ｎｍ正方で、厚みが３〜７ｎｍの大きさの１次結晶粒子が５〜１０個が塊状に凝集した１００〜３００ｎｍの大きさの２次粒子を形成する塊状結晶性アルミナ粒子（Ｒ３Ａ）分散液を得た。
＜工程（Ｂ）＞ この塊状結晶性アルミナ粒子（Ｒ３Ａ）分散液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナのアルミナ粒子（Ｒ３）分散液２０．０００ｋｇを得た。得られた塊状結晶性アルミナ粒子（３）は正方板状ではなく、直方体状でありさらに角が丸みを帯びた形状であった。
While maintaining this diluted sodium aluminate aqueous solution at 80 ° C., the entire amount of the diluted aluminum sulfate aqueous solution was added and mixed while stirring, and further maintained at 80 ° C. with stirring for 1 hour to obtain alumina fine particles (R3a) having a pH of 11.5. 33.333 kg of dispersion was obtained.
<Step (b)> After the alumina fine particle (R3a) dispersion was dehydrated with a degassing plate filter and the mother liquor was separated, the alumina fine particle cake obtained in the form of a plate filter was heated to 80 ° C. under reduced pressure at 80 ° C. 50 to 100 L is passed through, and sodium sulfate and adsorbed sodium contained in the alumina fine particle cake are washed and removed, and then sufficiently dehydrated under reduced pressure to obtain 6.667 kg of alumina fine particle (R3b) cake.
<Step (c)> To 6.667 kg of the alumina fine particle (R3b) cake, 12.983 kg of pure water was added and dispersed by sufficiently stirring to obtain an alumina hydrogel diluted dispersion liquid of 19.650 kg, and tetramethylammonium hydroxide was added thereto. 0.350 kg of an aqueous solution (manufactured by Kanto Chemical Co., Inc., concentration: 27% by mass) was added to obtain 20.000 kg of a basic substance-added alumina fine particle (R3c) dispersion.
<Step (A)> This basic substance-added alumina fine particle (R3c) dispersion is placed in an autoclave reactor, heated to 150 ° C. with stirring, and allowed to react for 24 hours under pressure, 30 to 70 nm square with a thickness of 3 A bulk crystalline alumina particle (R3A) dispersion was obtained which formed secondary particles with a size of 100 to 300 nm in which 5 to 10 primary crystal particles with a size of ˜7 nm were aggregated in a bulk shape.
<Step (B)> This bulk crystalline alumina particle (R3A) dispersion is put into an ultrafiltration device, washed with 60 ° C. hot pure water having a dilution rate of 1000 to 2000 times, and the residual nitrogen concentration is changed to tetramethyl. Washing was performed until the concentration in terms of ammonium was (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of an alumina particle (R3) dispersion of 5% by mass alumina. The obtained bulk crystalline alumina particles (3) were not a rectangular plate shape, but a rectangular parallelepiped shape and a shape with rounded corners.
塊状結晶性アルミナ粒子（Ｒ３）について、性状を表１に示す。
［比較例４］
＜塊状結晶性アルミナ粒子（Ｒ４）分散液の製造方法＞
＜工程（ｄ）＞ 市販の水酸化アルミニウム試薬（和光純薬工業株式会社製、特級、濃度９５質量％）１．６１０ｋｇへ純水１８．０４０ｋｇを加え、十分に撹拌して分散させ水酸化アルミニウム懸濁液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）０．３５０ｋｇを加え、塩基性物質添加水酸化アルミニウム（Ｒ４ｃ）懸濁液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加水酸化アルミニウム（Ｒ４ｃ）懸濁液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、６００〜９００ｎｍ正方で、厚みが４００〜８００ｎｍの大きさの１次結晶粒子が８〜１５個が塊状に凝集した４０００〜４６００ｎｍの大きさの２次粒子を形成する塊状結晶性アルミナ粒子（Ｒ４Ａ）懸濁液を得た。
＜工程（Ｂ）＞ この塊状結晶性アルミナ粒子（Ｒ４Ａ）懸濁液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナのアルミナ粒子（Ｒ４）懸濁液２０．０００ｋｇを得た。得られた塊状結晶性アルミナ粒子（Ｒ４）は正方板状ではなく、直方体及び立方体状の不揃いな形状であった。
Table 1 shows the properties of the bulk crystalline alumina particles (R3).
[Comparative Example 4]
<Method for Producing Bulk Crystalline Alumina Particle (R4) Dispersion>
<Step (d)> To a commercially available aluminum hydroxide reagent (Wako Pure Chemical Industries, Ltd., special grade, concentration 95% by mass) 1.610 kg, add pure water 18.040 kg, and sufficiently stir and disperse the aluminum hydroxide. 19.650 kg of a suspension was added, 0.350 kg of a tetramethylammonium hydroxide aqueous solution (concentration 27 mass%, manufactured by Kanto Chemical Co., Ltd.) was added thereto, and a basic substance-added aluminum hydroxide (R4c) suspension 20. 000 kg was obtained.
<Step (A)> This basic substance-added aluminum hydroxide (R4c) suspension is placed in an autoclave reactor, heated to 150 ° C. with stirring, and allowed to react for 24 hours under pressure, with a thickness of 600 to 900 nm square. A bulk crystalline alumina particle (R4A) suspension was obtained in which secondary particles having a size of 4000 to 4600 nm in which 8 to 15 primary crystal particles having a size of 400 to 800 nm were aggregated in a bulk shape were obtained.
<Step (B)> This massive crystalline alumina particle (R4A) suspension is put in an ultrafiltration apparatus, washed with warm pure water at a dilution rate of 1000 to 2000 times 60 ° C., and the remaining nitrogen concentration is changed to tetra. Washing was performed until the concentration in terms of methylammonium was (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of an alumina particle (R4) suspension of 5% by mass alumina. The obtained massive crystalline alumina particles (R4) were not a square plate shape, but were irregular shapes of a rectangular parallelepiped and a cube.
塊状結晶性アルミナ粒子（Ｒ４）について、性状を表１に示す。
［比較例５］
＜塊状結晶性アルミナ粒子（Ｒ５）分散液の製造方法＞
＜工程（ｄ）＞ 市販の正方板状ではない結晶性アルミナ微粒子パウダー(Ｓａｓｏｌ社製、Ｃａｔａｐａｌ−２００、濃度８０質量％)０．５００ｋｇへ純水１９．１５０ｋｇを加え、十分に撹拌して分散させアルミナ懸濁液１９．６５０ｋｇとし、これに、水酸化テトラメチルアンモニウム水溶液（関東化学株式会社製、濃度２７質量％）０．３５０ｋｇを加え、塩基性物質添加結晶性アルミナ（Ｒ５ｃ）懸濁液２０．０００ｋｇを得た。
＜工程（Ａ）＞ この塩基性物質添加結晶性アルミナ（Ｒ５ｃ）懸濁液をオートクレーブ反応器に入れ、撹拌下１５０℃へ加熱し、加圧下で２４時間反応させ、４０〜１００ｎｍ正方で、厚みが３０〜７０ｎｍの大きさの１次結晶粒子が５〜８個が塊状に凝集した２００〜４００ｎｍの大きさの２次粒子を形成する塊状結晶性アルミナ粒子（Ｒ５Ａ）懸濁液を得た。
＜工程（Ｂ）＞ この塊状結晶性アルミナ粒子（Ｒ５Ａ）懸濁液を限外濾過装置に入れ、希釈倍率１０００〜２０００倍量の６０℃の温純水にて洗浄を行い、残留する窒素濃度をテトラメチルアンモニウムに換算した濃度が（ＣＨ3）4Ｎ+＜１０ｐｐｍとなるまで洗浄を行い、５質量％アルミナのアルミナ粒子（Ｒ５）懸濁液２０．０００ｋｇを得た。得られた塊状結晶性アルミナ粒子（Ｒ５）は正方板状ではなく、直方体及び立方体状の不揃いな形状であった。
Table 1 shows the properties of the bulk crystalline alumina particles (R4).
[Comparative Example 5]
<Method for Producing Bulk Crystalline Alumina Particle (R5) Dispersion>
<Step (d)> A commercially available crystalline alumina fine particle powder which is not in the shape of a square plate (Sasol, Catapal-200, concentration 80% by mass) is added to 0.500 kg of pure water 19.150 kg and dispersed by sufficiently stirring. 19.650 kg of alumina suspension was added, and 0.350 kg of tetramethylammonium hydroxide aqueous solution (concentration 27 mass%, manufactured by Kanto Chemical Co., Ltd.) was added thereto, and a basic substance-added crystalline alumina (R5c) suspension was added. 20.000 kg was obtained.
<Step (A)> This basic substance-added crystalline alumina (R5c) suspension is placed in an autoclave reactor, heated to 150 ° C. with stirring, reacted under pressure for 24 hours, and has a thickness of 40 to 100 nm square. A bulk crystalline alumina particle (R5A) suspension was obtained that formed secondary particles with a size of 200 to 400 nm in which 5 to 8 primary crystal particles with a size of 30 to 70 nm were agglomerated.
<Step (B)> This massive crystalline alumina particle (R5A) suspension is put in an ultrafiltration apparatus, washed with warm pure water at a dilution rate of 1000 to 2000 times 60 ° C., and the remaining nitrogen concentration is changed to tetra. Washing was performed until the concentration in terms of methylammonium was (CH 3 ) 4 N + <10 ppm, to obtain 20.000 kg of an alumina particle (R5) suspension of 5% by mass alumina. The obtained massive crystalline alumina particles (R5) were not square plates, but were irregular shapes such as rectangular parallelepipeds and cubes.
塊状結晶性アルミナ粒子（Ｒ５）について、性状を表１に示す。 Table 1 shows the properties of the bulk crystalline alumina particles (R5).
本発明の結晶性アルミナ積層粒子は、粒子表面の凹凸を利用して研磨材としての利用でき、板状という形態から膜強度（曲げ強度、曲げ弾性率、荷重たわみ強度等）の向上が得られる。 The crystalline alumina laminated particle of the present invention can be used as an abrasive by utilizing the irregularities on the particle surface, and an improvement in film strength (bending strength, bending elastic modulus, load deflection strength, etc.) can be obtained from a plate-like form. .
粒子表面のフラクタル状の凹凸が形成されているため、の凹凸に起因する光学散乱、屈折率調整などの光学特性を発揮できる。
まだ粒子形状が特定の積層構造をしていることにより、表面電荷との相乗効果に起因して有機および／または無機溶媒系塗料等への混合の自由度が広という技術的効果を奏する。
Since the fractal unevenness on the particle surface is formed, optical characteristics such as optical scattering and refractive index adjustment due to the unevenness can be exhibited.
Since the particle shape is still a specific laminated structure, there is a technical effect that the degree of freedom of mixing into organic and / or inorganic solvent-based paints is wide due to a synergistic effect with the surface charge.
本発明の結晶性アルミナ積層粒子は、板状微粒子の集合したものであり粒子表面の凹凸を利用して研磨材としての利用でき、板状という形態から膜強度（曲げ強度、曲げ弾性率、荷重たわみ強度等）向上を狙った樹脂フィラーとして利用できる。 The crystalline alumina laminated particle of the present invention is an aggregate of plate-like fine particles and can be used as an abrasive by utilizing the irregularities on the surface of the particle. From the form of plate, film strength (bending strength, bending elastic modulus, load) It can be used as a resin filler aiming at improvement in deflection strength.
さらに、粒子表面は、複数の正方板状アルミナ微粒子が、少なくとも２辺が重なることなく積層した構造であるためナノオーダーのフラクタル状の凹凸が形成されているため、それに起因する光学特性が期待でき、このことを利用した化粧品、樹脂フィラー、表面コート材（光学散乱、屈折率調整など）への応用できる。 Furthermore, since the particle surface has a structure in which a plurality of square plate-like alumina fine particles are laminated without overlapping at least two sides, nano-order fractal irregularities are formed, so that optical characteristics resulting therefrom can be expected. , It can be applied to cosmetics, resin fillers, surface coating materials (optical scattering, refractive index adjustment, etc.) utilizing this.
表面電荷と粒子形状の相乗効果で有機・無機溶剤塗料等への混合の幅が広く、耐火難燃材、耐熱材として塗布／成型に利用できる。 Due to the synergistic effect of surface charge and particle shape, there is a wide range of mixing with organic and inorganic solvent paints, etc., and it can be used for coating / molding as a fire-resistant flame-retardant material and heat-resistant material.
Claims (12)
（Ｂ）前記工程（Ａ）で得られた結晶性アルミナ積層粒子から残留する塩基性物質を除去し、結晶性アルミナ積層粒子分散液を得る工程
を含むことを特徴とする上記（１）〜（６）のいずれかに記載の結晶性アルミナ積層粒子の製造方法。 (A) A step of obtaining a crystalline alumina laminated particle dispersion having a structure in which a plurality of square plate-like alumina fine particles are laminated so that at least two sides do not overlap by hydrothermally treating a dispersion of square plate-like alumina fine particles (B) removing the basic substance remaining from the crystalline alumina laminated particles obtained in the step (A) to obtain a crystalline alumina laminated particle dispersion, (1) to (1) above, 6) The manufacturing method of the crystalline alumina laminated particle in any one of.
（ａ）アルミン酸塩溶液に酸を添加した後、５０〜１００℃の温度で処理することにより１０〜１２の範囲にあるｐＨを有する正方板状アルミナ微粒子分散液を得る工程
（ｂ）前記工程（ａ）において得られた正方板状アルミナ微粒子分散液から残留する溶解性無機塩および未反応物質を除去する工程
（ｃ）前記工程（ｂ）で得られた正方板状アルミナ微粒子分散液に、さらに塩基性物質を添加して前記正方板状アルミナ微粒子の大きさを均一化する工程
を含むことを特徴とする請求項７に記載の結晶性アルミナ積層粒子の製造方法。 The square plate-like alumina fine particles used in the step (A) of claim 7 are: (a) After adding an acid to the aluminate solution, by treating at a temperature of 50 to 100 ° C., a pH in the range of 10 to 12 is obtained. (B) a step of removing residual inorganic salts and unreacted substances from the square plate-like alumina fine particle dispersion obtained in the step (a). The step of adding a basic substance to the square plate-like alumina fine particle dispersion obtained in (b) to make the size of the square plate-like alumina fine particles uniform is included. A method for producing crystalline alumina laminated particles.
（ｄ）工程（ａ）および工程（ｂ）を含まない工程により得られた正方板状アルミナ微粒子を分散液としたのち塩基性物質を添加して前記正方板状アルミナ微粒子の大きさを均一化する工程
によって得られたものであることを特徴とする請求項７に記載の結晶性アルミナ積層粒子の製造方法。 The dispersion of the square plate-like alumina fine particles used in the step (A) is a basic substance after (d) the square plate-like alumina fine particles obtained by the step not including the steps (a) and (b) are used as the dispersion. The method for producing crystalline alumina laminated particles according to claim 7, wherein the method is obtained by adding a slag to homogenize the size of the square plate-like alumina fine particles.
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