JPH0363123B2 - - Google Patents
Info
- Publication number
- JPH0363123B2 JPH0363123B2 JP15355684A JP15355684A JPH0363123B2 JP H0363123 B2 JPH0363123 B2 JP H0363123B2 JP 15355684 A JP15355684 A JP 15355684A JP 15355684 A JP15355684 A JP 15355684A JP H0363123 B2 JPH0363123 B2 JP H0363123B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- parts
- magnetic
- copolymer
- vinyl
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000005291 magnetic effect Effects 0.000 claims description 34
- 229920001577 copolymer Polymers 0.000 claims description 26
- 239000000843 powder Substances 0.000 claims description 16
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 claims description 13
- 230000005294 ferromagnetic effect Effects 0.000 claims description 12
- 235000014113 dietary fatty acids Nutrition 0.000 claims description 11
- 239000000194 fatty acid Substances 0.000 claims description 11
- 229930195729 fatty acid Natural products 0.000 claims description 11
- 150000004665 fatty acids Chemical class 0.000 claims description 10
- 238000006116 polymerization reaction Methods 0.000 claims description 10
- 150000003460 sulfonic acids Chemical class 0.000 claims description 9
- 229920001567 vinyl ester resin Polymers 0.000 claims description 9
- 125000004432 carbon atom Chemical group C* 0.000 claims description 8
- 239000000126 substance Substances 0.000 claims description 6
- 230000003472 neutralizing effect Effects 0.000 claims description 3
- 238000004581 coalescence Methods 0.000 claims 1
- 239000011230 binding agent Substances 0.000 description 24
- 229920000642 polymer Polymers 0.000 description 22
- 229920005989 resin Polymers 0.000 description 19
- 239000011347 resin Substances 0.000 description 19
- 230000015572 biosynthetic process Effects 0.000 description 13
- 238000003786 synthesis reaction Methods 0.000 description 13
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 12
- 239000006247 magnetic powder Substances 0.000 description 11
- 230000007423 decrease Effects 0.000 description 10
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- 230000005415 magnetization Effects 0.000 description 9
- 229920002554 vinyl polymer Polymers 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 238000007334 copolymerization reaction Methods 0.000 description 6
- 229920002635 polyurethane Polymers 0.000 description 6
- 239000004814 polyurethane Substances 0.000 description 6
- 238000001035 drying Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 4
- -1 acrylic ester Chemical class 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000010419 fine particle Substances 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 125000000542 sulfonic acid group Chemical group 0.000 description 4
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 3
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 229910006069 SO3H Inorganic materials 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 150000002148 esters Chemical group 0.000 description 3
- 125000000524 functional group Chemical group 0.000 description 3
- 239000012948 isocyanate Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000006386 neutralization reaction Methods 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 239000003973 paint Substances 0.000 description 3
- 229920005749 polyurethane resin Polymers 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 2
- IMROMDMJAWUWLK-UHFFFAOYSA-N Ethenol Chemical group OC=C IMROMDMJAWUWLK-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000000020 Nitrocellulose Substances 0.000 description 2
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 238000003490 calendering Methods 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 229910001429 cobalt ion Inorganic materials 0.000 description 2
- XLJKHNWPARRRJB-UHFFFAOYSA-N cobalt(2+) Chemical compound [Co+2] XLJKHNWPARRRJB-UHFFFAOYSA-N 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 239000000839 emulsion Substances 0.000 description 2
- UIWXSTHGICQLQT-UHFFFAOYSA-N ethenyl propanoate Chemical compound CCC(=O)OC=C UIWXSTHGICQLQT-UHFFFAOYSA-N 0.000 description 2
- 238000010528 free radical solution polymerization reaction Methods 0.000 description 2
- 150000002513 isocyanates Chemical class 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 2
- 229920001220 nitrocellulos Polymers 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 229920006267 polyester film Polymers 0.000 description 2
- 229920002545 silicone oil Polymers 0.000 description 2
- 229920003002 synthetic resin Polymers 0.000 description 2
- 239000000057 synthetic resin Substances 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- JHPBZFOKBAGZBL-UHFFFAOYSA-N (3-hydroxy-2,2,4-trimethylpentyl) 2-methylprop-2-enoate Chemical compound CC(C)C(O)C(C)(C)COC(=O)C(C)=C JHPBZFOKBAGZBL-UHFFFAOYSA-N 0.000 description 1
- OEPOKWHJYJXUGD-UHFFFAOYSA-N 2-(3-phenylmethoxyphenyl)-1,3-thiazole-4-carbaldehyde Chemical compound O=CC1=CSC(C=2C=C(OCC=3C=CC=CC=3)C=CC=2)=N1 OEPOKWHJYJXUGD-UHFFFAOYSA-N 0.000 description 1
- 229920000536 2-Acrylamido-2-methylpropane sulfonic acid Polymers 0.000 description 1
- GOXQRTZXKQZDDN-UHFFFAOYSA-N 2-Ethylhexyl acrylate Chemical compound CCCCC(CC)COC(=O)C=C GOXQRTZXKQZDDN-UHFFFAOYSA-N 0.000 description 1
- XHZPRMZZQOIPDS-UHFFFAOYSA-N 2-Methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid Chemical compound OS(=O)(=O)CC(C)(C)NC(=O)C=C XHZPRMZZQOIPDS-UHFFFAOYSA-N 0.000 description 1
- FXKMTSIKHBYZSZ-UHFFFAOYSA-N 2-chloroethanesulfonic acid Chemical compound OS(=O)(=O)CCCl FXKMTSIKHBYZSZ-UHFFFAOYSA-N 0.000 description 1
- VMSBGXAJJLPWKV-UHFFFAOYSA-N 2-ethenylbenzenesulfonic acid Chemical compound OS(=O)(=O)C1=CC=CC=C1C=C VMSBGXAJJLPWKV-UHFFFAOYSA-N 0.000 description 1
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229910020630 Co Ni Inorganic materials 0.000 description 1
- 229910002440 Co–Ni Inorganic materials 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229910017061 Fe Co Inorganic materials 0.000 description 1
- KYIMHWNKQXQBDG-UHFFFAOYSA-N N=C=O.N=C=O.CCCCCC Chemical compound N=C=O.N=C=O.CCCCCC KYIMHWNKQXQBDG-UHFFFAOYSA-N 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- ULUAUXLGCMPNKK-UHFFFAOYSA-N Sulfobutanedioic acid Chemical compound OC(=O)CC(C(O)=O)S(O)(=O)=O ULUAUXLGCMPNKK-UHFFFAOYSA-N 0.000 description 1
- 229920002433 Vinyl chloride-vinyl acetate copolymer Polymers 0.000 description 1
- QYKIQEUNHZKYBP-UHFFFAOYSA-N Vinyl ether Chemical class C=COC=C QYKIQEUNHZKYBP-UHFFFAOYSA-N 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000001476 alcoholic effect Effects 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 229910001870 ammonium persulfate Inorganic materials 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000001588 bifunctional effect Effects 0.000 description 1
- 238000012662 bulk polymerization Methods 0.000 description 1
- BRXCDHOLJPJLLT-UHFFFAOYSA-N butane-2-sulfonic acid Chemical compound CCC(C)S(O)(=O)=O BRXCDHOLJPJLLT-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- VZBZCLRLPBEOBO-UHFFFAOYSA-N carboxyoxy octan-3-yl carbonate Chemical compound CCCCCC(CC)OC(=O)OOC(O)=O VZBZCLRLPBEOBO-UHFFFAOYSA-N 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 125000001309 chloro group Chemical group Cl* 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000007033 dehydrochlorination reaction Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000010556 emulsion polymerization method Methods 0.000 description 1
- 238000007720 emulsion polymerization reaction Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- MPOGZNTVZCEKSW-UHFFFAOYSA-N ethenyl 2-hydroxypropanoate Chemical compound CC(O)C(=O)OC=C MPOGZNTVZCEKSW-UHFFFAOYSA-N 0.000 description 1
- AFSIMBWBBOJPJG-UHFFFAOYSA-N ethenyl octadecanoate Chemical compound CCCCCCCCCCCCCCCCCC(=O)OC=C AFSIMBWBBOJPJG-UHFFFAOYSA-N 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- IQPQWNKOIGAROB-UHFFFAOYSA-N isocyanate group Chemical group [N-]=C=O IQPQWNKOIGAROB-UHFFFAOYSA-N 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 150000002763 monocarboxylic acids Chemical group 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920001228 polyisocyanate Polymers 0.000 description 1
- 239000005056 polyisocyanate Substances 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 230000003449 preventive effect Effects 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 238000005185 salting out Methods 0.000 description 1
- 238000007127 saponification reaction Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- RPACBEVZENYWOL-XFULWGLBSA-M sodium;(2r)-2-[6-(4-chlorophenoxy)hexyl]oxirane-2-carboxylate Chemical compound [Na+].C=1C=C(Cl)C=CC=1OCCCCCC[C@]1(C(=O)[O-])CO1 RPACBEVZENYWOL-XFULWGLBSA-M 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000006277 sulfonation reaction Methods 0.000 description 1
- 125000001273 sulfonato group Chemical class [O-]S(*)(=O)=O 0.000 description 1
- 238000010558 suspension polymerization method Methods 0.000 description 1
- 238000010557 suspension polymerization reaction Methods 0.000 description 1
- 229920006027 ternary co-polymer Polymers 0.000 description 1
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 1
- NLVXSWCKKBEXTG-UHFFFAOYSA-N vinylsulfonic acid Chemical compound OS(=O)(=O)C=C NLVXSWCKKBEXTG-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Paints Or Removers (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Magnetic Record Carriers (AREA)
Description
(産業上の利用分野)
本発明は磁気記録媒体に関するものであり、特
に強磁性粉末の結合剤としてすぐれた性能を示す
塩化ビニルを主体とする特殊な三元系共重合体を
用いてなる改良された磁気記録媒体に関する。
(従来の技術)
磁気記録媒体は、一般にポリエステルなどの支
持体表面に磁性粉末を合成樹脂などの結合剤を用
いて塗布することによりつくられている。
磁性粉末としては、γ−Fe2O3,Fe3O4および
これらにコバルトイオンを吸着もしくはドープし
たもの、またはCr2Oなど、さらにはFe,Co,Fe
−Coもしくは場合によりNi等を含有させた針状
微粒子等が使用されているが、近年の家庭用の
VTRの普及やオーデイオカセツトテープの高性
能化により高い信号密度と短波長記録における高
再生出力が必要とされる。こうした動向に対処す
るため、磁性粉末がこれまでより一層微粒子化さ
れ、また非常に大きな磁気モーメントを有してい
るため、粒子が互いに凝集を起こし結合剤樹脂中
への均一分散が従来にも増して困難になつてきて
いる。
かかる技術的課題に対し、結合剤樹脂の性質と
して磁性粉末に対する親和性を向上させる観点か
ら、磁性微粒子たる金属酸化物や合金微粒子の有
する粒子表面の親水性の性質を結合剤樹脂にも持
たせる検討が広く行われている。
たとえば従来結合剤として実用に供されている
塩化ビニル−酢酸ビニルコポリマーについて、カ
ルボキシル基や水酸基などの親水性官能基を導入
することが行われているし、また「日本接着協会
誌」Vol.17、No.4(1981)、第155〜162頁の“磁気
テープと高分子”には、磁性塗料用結合剤として
の高分子物質に各種の親水性官能基を導入する研
究報文が掲載されており、これによれば結合剤中
のアンカーセグメントの種類とその効果について
官能基効果の序列が下記の如く記載されている。
また結合剤樹脂中にスルホン酸基を導入するこ
とについては特開昭58−108032号公報にも記載さ
れており、具体的にはビニルエステル、塩化ビニ
ル、塩化ビニリデン、アクリロニトリル、スチレ
ンなどのモノマーと、ビニルスルホン酸、ビニル
ベンゼンスルホン酸、2−アクリルアミド−2−
メチルプロパンスルホン酸などの重合性不飽和ス
ルホン酸とを共重合させてなるポリマーを磁性粉
末の結合剤として用いることが開示されている。
しかしスルホン酸基の導入は、たとえば塩化ビ
ニル−脂肪酸ビニル共重合体で検討した場合、磁
性粉末の分散性向上に確かにすぐれた効果がある
が、最近の強磁性微粉末に対してなお光沢不充分
としてあらわれ、また飽和磁化量を経時的に顕著
に低下させる欠点がある。なお、カルボキシル基
や水酸基の導入では分散性向上の効果が小さく目
的が達成されない。
他方ビニルアルコール単位が導入された共重合
体たとえば塩化ビニル−酢酸ビニル−ビニルアル
ール共重合体に対しそのOH基に分散性を向上さ
せる目的で、−SO3M、−COOM、−OSO3Mなどの
基(Mは金属原子)を含む親水性基団を導入して
なるポリマーを磁性粉末の結合剤樹脂として用い
ることが提案されている。しかし、この結合剤樹
脂は塩化ビニル−酢酸ビニルの共重合、該共重合
物のケン化、さらに同ケン化物のスルホン化とい
う3段階の複雑な反応工程によつて製造されるた
め工業的には高コストになるばかりでなく、1分
子中にOH基とCl原子とSO3M基などの金属塩基
を有するため脱HCl反応が起こり、これにより磁
気特性が経時的に劣化し、飽和磁化量が顕著に低
下する欠点がある。
(発明の構成)
本発明者らは上記のかかる欠点を解決し、各種
の磁性粉末に対してより分散性が良好で、かつ磁
気特性の経時的劣化を起こすことのない耐久性に
すぐれた結合剤樹脂を開発し、これを用いること
により性能、信頼性の高い磁気記録媒体を得るべ
く鋭意研究を重ねた結果、本発明に到達した。
すなわち本発明は、支持体上に、塩化ビニルと
炭素数8〜16の脂肪酸ビニルエステルと重合性不
飽和スルホン酸とを共重合させ、ついで塩基性物
質で中和して得た共重合体中に強磁性微粉末を分
散せしめた磁性層を形成してなる磁気記録媒体に
関するものである。
本発明に使用される結合剤樹脂は、強磁性微粉
末の分散性、充填性にすぐれている、適宜併用さ
れるポリウレタン樹脂等と充分な相溶性をもつて
いる、さらに分子中に酢酸ビニル、プロピオン酸
ビニル等の単位を含まないため熱分解反応、脱塩
酸反応がきわめて起こりにくい、という諸性能利
点をもつているので、これを使用することにより
長期耐久性の改善された高性能の磁気記録媒体を
得ることができる。
以下本発明を詳細に説明する。
本発明に使用される結合剤樹脂は前記した各単
量体の共重合体を塩基性物質で中和したものであ
るが、この共重合体としては特に塩化ビニル単位
65〜90重量%、炭素数8〜16の脂肪酸ビニルエス
テル単位8〜25重量%、および重合性不飽和スル
ホン酸単位0.1〜10重量%の割合からなり平均重
合度200〜800を有するものを使用することが望ま
しい。塩化ビニル単位が少なすぎると物理的強度
が低下するし、多すぎると溶解性が低下し使用上
不利である。脂肪酸ビニルエステル単位について
は、炭素数の小さいものたとえば酢酸ビニル、プ
ロピオン酸ビニル、らく酸ビニル等であると分散
性が悪くなるほかこれらの単位は熱分解を起こ
し、それに起因して塩化ビニルの脱塩酸が促進さ
れ、磁気記録媒体(磁気テープ等)の耐久性低下
が起こる。一方この脂肪酸ビニルエステルが分子
全体での炭素数が17以上であるような高分子のも
のたとえばステアリン酸ビニルであると分散性が
低下するので、分子全体での炭素数が8〜16の範
囲にある脂肪酸ビニルエステルを使用することが
望ましい。この脂肪酸部分については直鎖状と分
枝状の両方があるが、本発明の目的には分枝状の
ものが好ましく具体的にはバーチサツク酸(シエ
ル化学社製商品名、炭素数9,10または11の第三
級モノカルボン酸)のビニルエステルが好適とさ
れる。なお、共重合体中における脂肪酸ビニルエ
ステル単位量が少なすぎると溶解性が低下し、多
すぎると強磁性粉末の分散性が低下し、熱安定性
も低下して経時的磁気劣化が起こるので、前記し
た8〜25重量%の範囲とすることが望ましい。
重合性不飽和スルホン酸としては、
CH2=CH−SO3H、CH2=CH−C6H4−
SO3H、
CH2=CH−CO−NH−C(CH3)2
(CH2SO3H)、
(ただし式中のR′は炭素数12〜14のアルキル
基)
CH2=CH(CH3)−CO−O−C4O8−SO3H、
CH2=CH(CH3)−CO−O−C2H4−SO3H
などが例示される。
重合性不飽和スルホン酸の量が多すぎると溶解
性が悪くゲル化を起こしやすいし、逆に少なすぎ
ると磁性粉末の分散性が悪くなる。したがつてこ
の重合性不飽和スルホン酸の量は前記した範囲特
には0.5〜7重量%の範囲とすることが望ましい。
共重合体の重合度については、低くすぎると結
合剤としての強度が低下し、粉落ちが起こりやす
く耐久性が低下するし、また高すぎると粘度が高
くなり作業性が悪く分散性も低下するので、平均
重合度200〜800(特には250〜500)の範囲である
ことが望ましい。
なお、上記重合性不飽和スルホン酸に替えて重
合性不飽和スルホン酸塩を共重合に使用すると、
このスルホン酸塩は他の単量体である塩化ビニ
ル、脂肪酸ビニルエステル、および有機溶剤への
溶解性が乏しいため、均一に共重合しがたく、ま
た得られる共重合体は有機溶剤への溶解性が劣
り、本発明の目的、効果を達成することができな
い。
共重合体を得るための重合方法としては、従来
一般に採用されている塊状重合法、溶液重合法、
乳化重合法、懸濁重合法等によればよく、重合方
法それ自体に制限はない。本発明においては共重
合させて得た共重合体についてそのまま使用せず
塩基性物質で中和することが必要とされる。この
中和は共重合反応終了後に塩基性物質を加えるこ
とにより行われる。具体的には各重合法により望
ましい方法で実施すればよく、たとえば溶液重合
法においては重合反応終了後水酸化ナトリウムの
アルコール溶液を加えることにより中和し、引続
き共重合体の非溶剤であるアルコール系溶剤ある
いはn−ヘキサンなどの炭化水素系溶剤で再沈殿
し、同じ溶剤で洗浄し脱液乾燥することにより目
的の共重合体が得られる。また懸濁重合法におい
ては重合反応終了後の重合体スラリーにアルカリ
金属水酸化物の水溶液、アンモニア水等を加える
ことにより中和し、洗浄後脱液し乾燥することに
より共重合体が得られ、乳化重合法においてもほ
ぼ同じようにして中和した後常法にしたがつて塩
析、洗浄、過脱水し乾燥することにより共重合
体が取得される。
上記共重合体を結合剤樹脂として使用する際
に、必要に応じ他の樹脂が等量以下の量で併用さ
れてもよく、この併用し得る樹脂としてはポリウ
レタン樹脂、ニトロセルローズ、エポキシ樹脂、
ポリアミド樹脂、フエノール樹脂、あるいはアク
リル酸エステル、メタクリル酸エステル、スチレ
ン、アクリロニトリル、ブタジエン、エチレン、
プロピレン、塩化ビニリデン、アクリルアマイ
ド、ビニルエーテル類等の重合体または共重合体
等の各種ポリマーが例示される。これらのうちで
も特にポリウレタン樹脂、ニトロセルローズが好
適とされる。
この他にポリイソシアネート系硬化剤を併用す
ることは望ましいことであり、この硬化剤として
はトリレンジイソシアネート、ジフエニルメタン
ジイソシアネート、ヘキサンジイソシアネート等
の2官能イソシアネート、コロネートL(日本ポ
リウレタン工業製商品名)、デイスモジユールL
(バイエル社製商品名)等の3官能イソシアネー
ト、または両末端にイソシアネート基を含有する
ウレタンポリマーなどが例示される。なお、これ
ら硬化剤の使用量は結合剤樹脂100重量部当り40
重量部以下とすべきである。
本発明に使用される強磁性微粉末としては、γ
−Fe2O3、Fe3O4およびこれらにコバルトイオン
を吸着もしくはドープしたもの、またはCrO3な
ど、さらにはFe,Co,Fe−Coもしくは場合によ
りNi等を含有させた針状微粒子材料等、その他
従来公知の各種磁性粉末が例示される。強磁性微
粉末と結合剤樹脂との混合割合は、強磁性微粉末
100重量部当り結合剤樹脂8〜30重量部とするこ
とが望ましい。
なお、強磁性粉末と結合剤樹脂とを均一に分散
させるに当り、従来一般に使用されている潤滑
剤、研摩剤、帯電防止剤、分散助剤、防錆剤等を
添加すること、さらに塗布媒体としてメチルエチ
ルケトン、メチルイソブチルケトン、トルエンな
どその他各種の有機溶剤を使用することは従来と
同様でよく、これらの点に特別の制限はない。
支持体としてはポリエステル、ポリオレフイ
ン、セルロースアセテート、ポリカーボネートな
どの合成樹脂類、その他非磁性金属類、セラミツ
ク類が使用され、形態はフイルム、テープ、シー
ト、板状体等で使用される。
支持体上に磁性層を形成するための塗布手段と
しては従来公知の方法によればよく、適宜カレン
ダリング処理等の平滑化処理を施すことにより、
本発明の目的とする高性能磁気記録媒体が得られ
る。
つぎに結合剤樹脂の合成例およびその結合剤樹
脂を用いた具体的実施例をあげる。
合成例1 (ポリマーAの合成)
かくはん装置を備えたオートクレーブに、メタ
ノール400重量部、塩化ビニル86重量部、ベオバ
#10(シエル化学社製商品名)20重量部、アリル
ドデシルスルホサクシネート8重量部、ジ(2−
エチルヘキシル)パーオキシジカーボネート6重
量部および部分ケン化ポリビニルアルコール2重
量部を仕込み、窒素ガス雰囲気下にかくはんしな
がら50℃に昇温して反応を開始し、さらに塩化ビ
ニル86重量部を8時間要して連続圧入し共重合反
応させた。オートクレーブ内圧が12時間後に0
Kg/cm2になつた。得られたスラリーを冷却し10%
水酸化カリウム水溶液で中和し、1000重量部のメ
タノールで3回洗浄し、過し乾燥することによ
り共重合体粉末160重量部を得た。これをポリマ
ーAとする。
合成例2 (ポリマーBの合成)
かくはん装置を備えたオートクレーブに、下記
組成の仕込みを行い、
脱イオン水 400重量部
塩化ビニル 79 〃
ベオパ#9(バーサチツク酸ビニル、
シエル化学社製商品名) 24 〃
アクリル酸2−エチルヘキシル 10 〃
2−アクリルアミド−2−メチルプロパンスル
ホン酸 14 〃
過硫酸アンモニウム 1重量部
ポリオキシエチレンノニルフエニルエーテル
4 〃
かくはんしながら55℃に加温して反応を開始し
た。さらに塩化ビニル80重量部を8時間要して連
続的に添加し共重合反応させ、さらに1時間熱反
応を行いエマルジヨンを得た。このエマルジヨン
を28%アンモニア水溶液で中和し、さらに塩化ナ
トリウム50重量部、熱水500重量部を加えた後ス
ラリーを過しケーキを得た。このものを1200重
量部の水に分散させ過する洗浄工程を5回行つ
た後乾燥することにより共重合体粉末125重量部
を得た。これをポリマーBとする。
比較合成例1 (ポリマーCの合成)
合成例1において、10%水酸化カリウム水溶液
による中和を省略した以外は全く同様にして共重
合体を得た。これをポリマーCとする。
比較合成例2 (ポリマーDの合成)
合成例1において、ベオバ#10の代りに酢酸ビ
ニルを20重量部使用したほかは全く同様にして共
重合体を得た。これをポリマーDとする。
比較合成例3 (ポリマーEの合成)
冷却管およびかくはん機を備えた反応器に、塩
化ビニル−酢酸ビニル−ビニルアルコール共重合
体(ビニルアルコール12重量%)100重量部、ジ
メチルホルムアミド400重量部、ピリジン21.5重
量部およびモノクロルエチルスルホネートNa塩
(Cl−C2H4OSO3Na)45重量部を仕込み、80℃で
10時間反応させ、冷却後固形物を過し、メタノ
ール1000重量部に加えポリマーを析出させた。さ
らにメタノール1000重量部を用いて分散洗浄する
操作を3回繰り返し行い、乾燥することにより共
重合体粉末を88重量部得た。これをポリマーEと
する。
実施例1および2
強磁性粉末としてCo−γ−Fe2O3(保持力640エ
ルステツド、飽和磁化74emu/g、比表面積23
m2/g)300重量部、ポリマーAまたはBを30重
量部、ポリウレタンニツポランN−5032(日本ポ
リウレタン工業製商品名)20重量部、シリコーン
オイルKF−96(信越化学工業製商品名)0.5重量
部、メチルエチルケトン300重量部、メチルイソ
ブチルケトン300重量部およびトルエン300重量部
からなる組成物をボールミルで10時間混練分散
し、ついでコロネートL(日本ポリウレタン工業
製商品名、低分子量イソシアネート化合物)25重
量部を加え再度ボールミルで1時間混練分散し
た。このようにして得た磁性塗料をポリエステル
フイルム上に乾燥膜厚5μmになるように塗布し、
磁場配向処理を行い乾燥した。
こうして得た磁気記録媒体について、表面光沢
および磁気特性を測定した。表面光沢はグロスメ
ーターGM−3D(村上色彩技研)を用い、Gs60゜の
光反射率を標準ガラス板と比較測定した。また磁
気特性はVSM−3型(東英工業製)を用いて外
部磁場3000エルステツドで測定した。結果は第1
表に示すとおりであつた。
比較例 1
実施例1において、ポリマーAまたはBの代り
にポリマーCを用いた以外は同様にして磁気記録
媒体をつくり、表面光沢および磁気特性を測定し
た。結果は第1表に示すとおりであつた。
(Industrial Application Field) The present invention relates to a magnetic recording medium, and in particular an improvement using a special ternary copolymer mainly composed of vinyl chloride, which exhibits excellent performance as a binder for ferromagnetic powder. The present invention relates to magnetic recording media. (Prior Art) Magnetic recording media are generally made by applying magnetic powder to the surface of a support such as polyester using a binder such as synthetic resin. Examples of magnetic powders include γ-Fe 2 O 3 , Fe 3 O 4 and those obtained by adsorbing or doping cobalt ions, or Cr 2 O, as well as Fe, Co, Fe, etc.
-Acicular fine particles containing Co or Ni in some cases are used, but in recent years household use
With the spread of VTRs and the improved performance of audio cassette tapes, high signal density and high playback output for short wavelength recording are required. In order to cope with these trends, magnetic powder has become finer than ever before, and has an extremely large magnetic moment, which causes the particles to coagulate with each other, making it possible to disperse them more uniformly in the binder resin than before. It's becoming difficult. To solve this technical problem, from the viewpoint of improving the affinity of the binder resin for magnetic powder, it is necessary to impart to the binder resin the hydrophilic properties of the particle surface of metal oxide and alloy fine particles, which are magnetic fine particles. It is being widely studied. For example, hydrophilic functional groups such as carboxyl groups and hydroxyl groups have been introduced into the vinyl chloride-vinyl acetate copolymer, which has been used practically as a binder. , No. 4 (1981), pp. 155-162, "Magnetic Tape and Polymers," contains a research report on introducing various hydrophilic functional groups into polymeric materials used as binders for magnetic paints. According to this document, the types of anchor segments in the binder and the order of functional group effects are described as follows. JP-A No. 58-108032 also describes the introduction of sulfonic acid groups into binder resins. , vinylsulfonic acid, vinylbenzenesulfonic acid, 2-acrylamide-2-
It has been disclosed that a polymer obtained by copolymerizing a polymerizable unsaturated sulfonic acid such as methylpropanesulfonic acid is used as a binder for magnetic powder. However, although the introduction of sulfonic acid groups does have an excellent effect on improving the dispersibility of magnetic powder when examined, for example, in the case of vinyl chloride-vinyl fatty acid copolymers, the introduction of sulfonic acid groups is still effective in improving the dispersibility of magnetic powders. It appears to be insufficient, and also has the disadvantage that the amount of saturation magnetization decreases significantly over time. Note that the introduction of carboxyl groups or hydroxyl groups has a small effect on improving dispersibility, and the purpose is not achieved. On the other hand, for copolymers into which vinyl alcohol units have been introduced, such as vinyl chloride-vinyl acetate-vinyl alcohol copolymers, -SO 3 M, -COOM, -OSO 3 M, etc. are added for the purpose of improving the dispersibility of the OH groups. It has been proposed to use a polymer formed by introducing a hydrophilic group containing a group (M is a metal atom) as a binder resin for magnetic powder. However, this binder resin is manufactured through a complicated three-step reaction process: copolymerization of vinyl chloride and vinyl acetate, saponification of the copolymer, and sulfonation of the saponified product, so it is not suitable for industrial use. Not only is the cost high, but because each molecule contains an OH group, a Cl atom, and a metal base such as an SO 3 M group, a de-HCl reaction occurs, which deteriorates the magnetic properties over time and reduces the saturation magnetization. There is a drawback that it decreases significantly. (Structure of the Invention) The present inventors have solved the above-mentioned drawbacks, and have created a bond that has better dispersibility for various magnetic powders and has excellent durability without causing deterioration of magnetic properties over time. The present invention was achieved as a result of extensive research aimed at developing a magnetic recording medium and using it to obtain a magnetic recording medium with high performance and reliability. That is, the present invention provides a copolymer obtained by copolymerizing vinyl chloride, a fatty acid vinyl ester having 8 to 16 carbon atoms, and a polymerizable unsaturated sulfonic acid on a support, and then neutralizing it with a basic substance. The present invention relates to a magnetic recording medium in which a magnetic layer in which fine ferromagnetic powder is dispersed is formed. The binder resin used in the present invention has excellent dispersibility and filling properties of the ferromagnetic fine powder, has sufficient compatibility with the polyurethane resin etc. used in combination, and also has vinyl acetate in the molecule. Since it does not contain units such as vinyl propionate, it has various performance advantages such as thermal decomposition reactions and dehydrochlorination reactions are extremely difficult to occur, so by using it, high performance magnetic recording with improved long-term durability can be achieved. medium can be obtained. The present invention will be explained in detail below. The binder resin used in the present invention is a copolymer of each of the monomers described above neutralized with a basic substance, and this copolymer is particularly suitable for vinyl chloride units.
65 to 90% by weight, 8 to 25% by weight of fatty acid vinyl ester units having 8 to 16 carbon atoms, and 0.1 to 10% by weight of polymerizable unsaturated sulfonic acid units, and having an average degree of polymerization of 200 to 800. It is desirable to do so. If the vinyl chloride unit is too small, the physical strength will be reduced, and if it is too large, the solubility will be reduced, which is disadvantageous in use. Regarding fatty acid vinyl ester units, those with a small number of carbon atoms, such as vinyl acetate, vinyl propionate, vinyl lactate, etc., will not only have poor dispersibility, but also cause thermal decomposition of these units, resulting in the elimination of vinyl chloride. Hydrochloric acid is accelerated and the durability of magnetic recording media (magnetic tape, etc.) decreases. On the other hand, if this fatty acid vinyl ester is a polymer with a total number of carbon atoms of 17 or more in the molecule, such as vinyl stearate, the dispersibility will decrease, so if the total number of carbon atoms in the molecule is in the range of 8 to 16, the dispersibility will decrease. It is desirable to use certain fatty acid vinyl esters. This fatty acid moiety can be both linear and branched, but for the purposes of the present invention, branched fatty acids are preferred, specifically birtissuccinic acid (trade name manufactured by Ciel Chemical Co., Ltd., carbon number 9, 10 or 11 tertiary monocarboxylic acids) is preferred. In addition, if the amount of fatty acid vinyl ester units in the copolymer is too small, the solubility will decrease, and if it is too large, the dispersibility of the ferromagnetic powder will decrease, and the thermal stability will also decrease, causing magnetic deterioration over time. The content is preferably in the range of 8 to 25% by weight. As polymerizable unsaturated sulfonic acids, CH 2 = CH-SO 3 H, CH 2 = CH-C 6 H 4 -
SO3H , CH2 =CH-CO-NH-C( CH3 ) 2
( CH2SO3H ), (However, R' in the formula is an alkyl group having 12 to 14 carbon atoms) CH2 =CH( CH3 )-CO-O- C4O8 - SO3H , CH2 =CH( CH3 )-CO- Examples include O - C2H4 - SO3H . If the amount of polymerizable unsaturated sulfonic acid is too large, the solubility will be poor and gelation will easily occur, while if the amount is too small, the dispersibility of the magnetic powder will be poor. Therefore, it is desirable that the amount of this polymerizable unsaturated sulfonic acid be within the range described above, particularly within the range of 0.5 to 7% by weight. Regarding the degree of polymerization of the copolymer, if it is too low, its strength as a binder will be reduced and powder will easily fall off, reducing durability. If it is too high, the viscosity will become high, resulting in poor workability and reduced dispersibility. Therefore, it is desirable that the average degree of polymerization is in the range of 200 to 800 (particularly 250 to 500). In addition, if a polymerizable unsaturated sulfonic acid salt is used in the copolymerization instead of the above polymerizable unsaturated sulfonic acid,
This sulfonate has poor solubility in other monomers such as vinyl chloride, fatty acid vinyl ester, and organic solvents, so it is difficult to uniformly copolymerize, and the resulting copolymer is difficult to dissolve in organic solvents. Therefore, the objects and effects of the present invention cannot be achieved. Polymerization methods for obtaining copolymers include bulk polymerization, solution polymerization, and
Emulsion polymerization, suspension polymerization, etc. may be used, and the polymerization method itself is not limited. In the present invention, the copolymer obtained by copolymerization must not be used as it is, but must be neutralized with a basic substance. This neutralization is carried out by adding a basic substance after the copolymerization reaction is completed. Specifically, it may be carried out in a manner desired by each polymerization method. For example, in the solution polymerization method, after the polymerization reaction is completed, neutralization is performed by adding an alcoholic solution of sodium hydroxide, and then alcohol, which is a non-solvent for the copolymer, is added to neutralize the polymerization reaction. The desired copolymer can be obtained by reprecipitating with a solvent or a hydrocarbon solvent such as n-hexane, washing with the same solvent, and removing liquid and drying. In addition, in the suspension polymerization method, the polymer slurry after the polymerization reaction is neutralized by adding an aqueous solution of alkali metal hydroxide, aqueous ammonia, etc., and the copolymer is obtained by washing, removing liquid, and drying. In the emulsion polymerization method, a copolymer is obtained by neutralizing in substantially the same manner, followed by salting out, washing, excessive dehydration, and drying in accordance with conventional methods. When using the above-mentioned copolymer as a binder resin, other resins may be used in equal or less amounts as necessary, and resins that can be used in combination include polyurethane resins, nitrocellulose, epoxy resins,
Polyamide resin, phenolic resin, acrylic ester, methacrylic ester, styrene, acrylonitrile, butadiene, ethylene,
Examples include various polymers such as propylene, vinylidene chloride, acrylamide, vinyl ethers, and copolymers. Among these, polyurethane resins and nitrocellulose are particularly preferred. In addition, it is desirable to use a polyisocyanate-based curing agent in combination, and examples of this curing agent include bifunctional isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and hexane diisocyanate, and Coronate L (trade name, manufactured by Nippon Polyurethane Industries). , Days module L
Examples include trifunctional isocyanates such as (trade name, manufactured by Bayer AG), and urethane polymers containing isocyanate groups at both ends. The amount of these curing agents used is 40% per 100 parts by weight of binder resin.
It should be less than parts by weight. The ferromagnetic fine powder used in the present invention includes γ
- Fe 2 O 3 , Fe 3 O 4 and these adsorbed or doped with cobalt ions, CrO 3 etc., and acicular fine particle materials containing Fe, Co, Fe-Co or in some cases Ni etc. , and various other conventionally known magnetic powders. The mixing ratio of ferromagnetic fine powder and binder resin is
Preferably, the amount of binder resin is 8 to 30 parts by weight per 100 parts by weight. In addition, in order to uniformly disperse the ferromagnetic powder and the binder resin, it is necessary to add commonly used lubricants, abrasives, antistatic agents, dispersion aids, rust preventives, etc., as well as coating media. Various other organic solvents such as methyl ethyl ketone, methyl isobutyl ketone, and toluene may be used as in the past, and there are no particular restrictions on these points. As the support, synthetic resins such as polyester, polyolefin, cellulose acetate, and polycarbonate, other nonmagnetic metals, and ceramics are used, and the support is in the form of a film, tape, sheet, plate, etc. The coating means for forming the magnetic layer on the support may be any conventionally known method, and by appropriately performing a smoothing treatment such as calendaring treatment,
A high-performance magnetic recording medium, which is the object of the present invention, can be obtained. Next, examples of synthesis of binder resins and specific examples using the binder resins will be given. Synthesis Example 1 (Synthesis of Polymer A) In an autoclave equipped with a stirring device, 400 parts by weight of methanol, 86 parts by weight of vinyl chloride, 20 parts by weight of Beoba #10 (trade name manufactured by Ciel Chemical Co., Ltd.), and 8 parts by weight of allyldodecyl sulfosuccinate. part, di(2-
6 parts by weight of (ethylhexyl) peroxydicarbonate and 2 parts by weight of partially saponified polyvinyl alcohol were charged, and the temperature was raised to 50°C while stirring in a nitrogen gas atmosphere to start the reaction, and then 86 parts by weight of vinyl chloride was added for 8 hours. In short, continuous pressure injection was carried out to cause a copolymerization reaction. Autoclave internal pressure reaches 0 after 12 hours
Kg/ cm2 . Cool the resulting slurry to 10%
The mixture was neutralized with an aqueous potassium hydroxide solution, washed three times with 1000 parts by weight of methanol, and filtered and dried to obtain 160 parts by weight of a copolymer powder. This is called Polymer A. Synthesis Example 2 (Synthesis of Polymer B) The following composition was charged into an autoclave equipped with a stirring device: Deionized water 400 parts by weight Vinyl chloride 79 Beopa #9 (vinyl versatility, trade name manufactured by Ciel Chemical Co., Ltd.) 24 〃 2-ethylhexyl acrylate 10 〃 2-acrylamido-2-methylpropanesulfonic acid 14 〃 Ammonium persulfate 1 part by weight polyoxyethylene nonyl phenyl ether
4. The reaction was started by heating to 55°C while stirring. Further, 80 parts by weight of vinyl chloride was continuously added over a period of 8 hours to cause a copolymerization reaction, and a thermal reaction was further carried out for 1 hour to obtain an emulsion. This emulsion was neutralized with a 28% ammonia aqueous solution, 50 parts by weight of sodium chloride and 500 parts by weight of hot water were added, and the slurry was filtered to obtain a cake. This product was dispersed in 1200 parts by weight of water, washed five times, and then dried to obtain 125 parts by weight of copolymer powder. This will be referred to as Polymer B. Comparative Synthesis Example 1 (Synthesis of Polymer C) A copolymer was obtained in exactly the same manner as Synthesis Example 1 except that neutralization with a 10% aqueous potassium hydroxide solution was omitted. This will be referred to as Polymer C. Comparative Synthesis Example 2 (Synthesis of Polymer D) A copolymer was obtained in exactly the same manner as in Synthesis Example 1 except that 20 parts by weight of vinyl acetate was used instead of Beoba #10. This will be referred to as Polymer D. Comparative Synthesis Example 3 (Synthesis of Polymer E) In a reactor equipped with a cooling tube and a stirrer, 100 parts by weight of vinyl chloride-vinyl acetate-vinyl alcohol copolymer (vinyl alcohol 12% by weight), 400 parts by weight of dimethylformamide, 21.5 parts by weight of pyridine and 45 parts by weight of monochloroethylsulfonate Na salt (Cl-C 2 H 4 OSO 3 Na) were charged and heated at 80℃.
The reaction was allowed to proceed for 10 hours, and after cooling, the solid matter was filtered and added to 1000 parts by weight of methanol to precipitate a polymer. Furthermore, the operation of dispersing and washing using 1000 parts by weight of methanol was repeated three times, followed by drying to obtain 88 parts by weight of copolymer powder. This is called Polymer E. Examples 1 and 2 Co-γ-Fe 2 O 3 as ferromagnetic powder (coercive force 640 oersted, saturation magnetization 74 emu/g, specific surface area 23
m 2 /g) 300 parts by weight, 30 parts by weight of polymer A or B, 20 parts by weight of polyurethane Nituporan N-5032 (trade name manufactured by Nippon Polyurethane Industries), 0.5 parts by weight of silicone oil KF-96 (trade name manufactured by Shin-Etsu Chemical Industries). A composition consisting of 300 parts by weight of methyl ethyl ketone, 300 parts by weight of methyl isobutyl ketone and 300 parts by weight of toluene was kneaded and dispersed in a ball mill for 10 hours, and then 25 parts by weight of Coronate L (trade name, manufactured by Nippon Polyurethane Industries, Ltd., a low molecular weight isocyanate compound) was added. of the mixture was added and kneaded and dispersed again in a ball mill for 1 hour. The magnetic paint thus obtained was applied onto a polyester film to a dry film thickness of 5 μm.
It was subjected to magnetic field orientation treatment and dried. The surface gloss and magnetic properties of the magnetic recording medium thus obtained were measured. The surface gloss was measured by comparing the light reflectance at Gs60° with a standard glass plate using a gloss meter GM-3D (Murakami Color Giken). The magnetic properties were measured using a VSM-3 model (manufactured by Toei Kogyo) in an external magnetic field of 3000 oersteds. The result is the first
It was as shown in the table. Comparative Example 1 A magnetic recording medium was produced in the same manner as in Example 1 except that Polymer C was used instead of Polymer A or B, and the surface gloss and magnetic properties were measured. The results were as shown in Table 1.
【表】
実施例3および4、比較例2〜4
強磁性粉末 Fe−Co−Ni 300重量部
保持力1500エルステツド
飽和磁化135emu/g
比表面積50/g
結合剤樹脂
(ポリマーA,B,C,DまたはE) 30重量部
ポリウレタンニツポランN−3022
(日本ポリウレタン工業製商品名) 20重量部
シリコーンオイルKF−96 3重量部
メチルエチルケトン 300重量部
メチルイソブチルケトン 300重量部
トルエン 300重量部
上記組成物をボールミルで10時間混練分散し、
さらにコロネートL(前出)2重量部加え再度ボ
ールミルで1時間混練分散した。このようにして
得た磁性塗料をポリエステルフイルム上に乾燥膜
厚5μmになるように塗布し、磁場配向処理を行い
乾燥後カレンダリング処理を行つた。
このようにして得た各テープについて、前例と
同様にして表面光沢および磁気特性を測定すると
共に、強磁性粉末の結合剤樹脂に対する耐酸化性
を評価するため、各テープを空気中60℃、90%
RHに放置し、経時促進下における飽和磁化量の
低下率を求めた。結果は第2表に示すとおりであ
つた。
飽和磁化量の低下率=σSO−σST/σSO×100
σSO:初期飽和磁化量(emu/g)
σST:促進テスト後飽和磁化量(emu/g)[Table] Examples 3 and 4, Comparative Examples 2 to 4 Ferromagnetic powder Fe-Co-Ni 300 parts by weight Retention force 1500 Oersted saturation magnetization 135 emu/g Specific surface area 50/g Binder resin (Polymer A, B, C, D or E) 30 parts by weight Polyurethane Nitsuporan N-3022 (trade name manufactured by Nippon Polyurethane Industries) 20 parts by weight Silicone oil KF-96 3 parts by weight Methyl ethyl ketone 300 parts by weight Methyl isobutyl ketone 300 parts by weight Toluene 300 parts by weight The above composition Kneaded and dispersed in a ball mill for 10 hours,
Furthermore, 2 parts by weight of Coronate L (described above) was added and kneaded and dispersed again in a ball mill for 1 hour. The magnetic paint thus obtained was applied onto a polyester film to a dry film thickness of 5 μm, subjected to magnetic field orientation treatment, and after drying, calendering treatment was performed. For each tape thus obtained, the surface gloss and magnetic properties were measured in the same manner as in the previous example, and in order to evaluate the oxidation resistance of the ferromagnetic powder to the binder resin, each tape was heated in air at 60℃ and 90℃. %
The rate of decrease in saturation magnetization was determined after being left at RH and accelerated over time. The results were as shown in Table 2. Decrease rate of saturation magnetization = σ SO −σ ST /σ SO ×100 σ SO : Initial saturation magnetization (emu/g) σ ST : Saturation magnetization after accelerated test (emu/g)
【表】
以上の各実施例および比較例から判るように、
本発明による磁気記録媒体は強磁性微粉末の分散
性が優秀であり、かつ飽和磁化量の経時変化が小
さく、耐酸化性にすぐれている。[Table] As can be seen from the above examples and comparative examples,
The magnetic recording medium according to the present invention has excellent dispersibility of ferromagnetic fine powder, small change in saturation magnetization over time, and excellent oxidation resistance.
Claims (1)
肪酸ビニルエステルと重合性不飽和スルホン酸と
を共重合させ、ついで塩基性物質で中和して得た
共重合体中に強磁性微粉末を分散せしめた磁性層
を形成してなる磁気記録媒体。 2 前記共重合体が、塩化ビニル65〜90重量%、
炭素数8〜16の脂肪酸ビニルエステル8〜25重量
%および重合性不飽和スルホン酸0.1〜10重量%
の割合で共重合させて得た平均重合度200〜800を
有するものである特許請求の範囲第1項記載の磁
気記録媒体。[Claims] 1. A copolymer obtained by copolymerizing vinyl chloride, a fatty acid vinyl ester having 8 to 16 carbon atoms, and a polymerizable unsaturated sulfonic acid on a support, and then neutralizing it with a basic substance. A magnetic recording medium formed by forming a magnetic layer in which fine ferromagnetic powder is dispersed during coalescence. 2 The copolymer contains 65 to 90% by weight of vinyl chloride,
8-25% by weight of fatty acid vinyl ester having 8-16 carbon atoms and 0.1-10% by weight of polymerizable unsaturated sulfonic acid
2. The magnetic recording medium according to claim 1, which has an average degree of polymerization of 200 to 800 obtained by copolymerizing at a ratio of .
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15355684A JPS6132216A (en) | 1984-07-24 | 1984-07-24 | Magnetic recording medium |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15355684A JPS6132216A (en) | 1984-07-24 | 1984-07-24 | Magnetic recording medium |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6132216A JPS6132216A (en) | 1986-02-14 |
JPH0363123B2 true JPH0363123B2 (en) | 1991-09-30 |
Family
ID=15565080
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP15355684A Granted JPS6132216A (en) | 1984-07-24 | 1984-07-24 | Magnetic recording medium |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6132216A (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5424796B2 (en) * | 2009-09-29 | 2014-02-26 | 富士フイルム株式会社 | Binder for magnetic recording medium, composition for magnetic recording medium, and magnetic recording medium |
-
1984
- 1984-07-24 JP JP15355684A patent/JPS6132216A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS6132216A (en) | 1986-02-14 |
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