JPH0234087B2 - - Google Patents
Info
- Publication number
- JPH0234087B2 JPH0234087B2 JP54151096A JP15109679A JPH0234087B2 JP H0234087 B2 JPH0234087 B2 JP H0234087B2 JP 54151096 A JP54151096 A JP 54151096A JP 15109679 A JP15109679 A JP 15109679A JP H0234087 B2 JPH0234087 B2 JP H0234087B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- polyvinyl butyral
- resin containing
- polyester resin
- sulfonic acid
- 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 - Lifetime
Links
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 claims description 18
- 229920001225 polyester resin Polymers 0.000 claims description 18
- 239000004645 polyester resin Substances 0.000 claims description 18
- 229910052751 metal Inorganic materials 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 16
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 claims description 14
- 239000011230 binding agent Substances 0.000 claims description 12
- 229920005989 resin Polymers 0.000 claims description 7
- 239000011347 resin Substances 0.000 claims description 7
- 239000012948 isocyanate Substances 0.000 claims description 6
- -1 isocyanate compound Chemical class 0.000 claims description 6
- 229920001634 Copolyester Polymers 0.000 claims description 5
- 239000006247 magnetic powder Substances 0.000 description 18
- 239000002904 solvent Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 9
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 8
- 239000003973 paint Substances 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- 229910052708 sodium Inorganic materials 0.000 description 8
- 239000011734 sodium Substances 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- 239000000758 substrate Substances 0.000 description 7
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- CXMXRPHRNRROMY-UHFFFAOYSA-N sebacic acid Chemical compound OC(=O)CCCCCCCCC(O)=O CXMXRPHRNRROMY-UHFFFAOYSA-N 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- YZTJKOLMWJNVFH-UHFFFAOYSA-N 2-sulfobenzene-1,3-dicarboxylic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1S(O)(=O)=O YZTJKOLMWJNVFH-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
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- SLCVBVWXLSEKPL-UHFFFAOYSA-N neopentyl glycol Chemical compound OCC(C)(C)CO SLCVBVWXLSEKPL-UHFFFAOYSA-N 0.000 description 3
- 229910052700 potassium Inorganic materials 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- NIQCNGHVCWTJSM-UHFFFAOYSA-N Dimethyl phthalate Chemical compound COC(=O)C1=CC=CC=C1C(=O)OC NIQCNGHVCWTJSM-UHFFFAOYSA-N 0.000 description 2
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 2
- VNGOYPQMJFJDLV-UHFFFAOYSA-N dimethyl benzene-1,3-dicarboxylate Chemical compound COC(=O)C1=CC=CC(C(=O)OC)=C1 VNGOYPQMJFJDLV-UHFFFAOYSA-N 0.000 description 2
- WOZVHXUHUFLZGK-UHFFFAOYSA-N dimethyl terephthalate Chemical compound COC(=O)C1=CC=C(C(=O)OC)C=C1 WOZVHXUHUFLZGK-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000006068 polycondensation reaction Methods 0.000 description 2
- 229920006267 polyester film Polymers 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 2
- 238000005809 transesterification reaction Methods 0.000 description 2
- RTTZISZSHSCFRH-UHFFFAOYSA-N 1,3-bis(isocyanatomethyl)benzene Chemical compound O=C=NCC1=CC=CC(CN=C=O)=C1 RTTZISZSHSCFRH-UHFFFAOYSA-N 0.000 description 1
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- RAADBCJYJHQQBI-UHFFFAOYSA-N 2-sulfoterephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C(S(O)(=O)=O)=C1 RAADBCJYJHQQBI-UHFFFAOYSA-N 0.000 description 1
- ZTQSAGDEMFDKMZ-UHFFFAOYSA-N Butyraldehyde Chemical compound CCCC=O ZTQSAGDEMFDKMZ-UHFFFAOYSA-N 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 1
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical compound ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 1
- ZOIORXHNWRGPMV-UHFFFAOYSA-N acetic acid;zinc Chemical compound [Zn].CC(O)=O.CC(O)=O ZOIORXHNWRGPMV-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000002390 adhesive tape Substances 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 125000005442 diisocyanate group Chemical group 0.000 description 1
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 1
- FBSAITBEAPNWJG-UHFFFAOYSA-N dimethyl phthalate Natural products CC(=O)OC1=CC=CC=C1OC(C)=O FBSAITBEAPNWJG-UHFFFAOYSA-N 0.000 description 1
- 229960001826 dimethylphthalate Drugs 0.000 description 1
- VVTXSHLLIKXMPY-UHFFFAOYSA-L disodium;2-sulfobenzene-1,3-dicarboxylate Chemical compound [Na+].[Na+].OS(=O)(=O)C1=C(C([O-])=O)C=CC=C1C([O-])=O VVTXSHLLIKXMPY-UHFFFAOYSA-L 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- IQPQWNKOIGAROB-UHFFFAOYSA-N isocyanate group Chemical group [N-]=C=O IQPQWNKOIGAROB-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000004246 zinc acetate Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Paints Or Removers (AREA)
- Magnetic Record Carriers (AREA)
Description
〔産業上の利用分野〕
この発明は磁気記録媒体に関し、さらに詳しく
は磁性粉末の分散性、充填性に優れ、磁性層の表
面平滑性および基体との接着性に優れるととも
に、さらに耐久性および耐溶剤性に優れた磁気記
録媒体に関する。
〔従来の技術〕
磁気記録媒体は、通常、磁性粉末、結合剤成
分、有機溶剤およびその他の必要成分からなる磁
性塗料をポリエステルフイルムなどの基体上に塗
布、乾燥してつくられる。この際使用される結合
剤成分としては、磁性粉末の分散性および充填性
に優れ、磁性層の表面平滑性を良好にして磁気記
録媒体に高SN比などの優れた電気的特性を付与
できるとともに、基体との接着性に優れ、さらに
耐久性および耐溶剤性に優れるものを選ぶ必要が
あり、特にビデオテープなどのようにその電気的
特性が磁性層表面の平滑性に大きく依存し、磁性
層の表面平滑性が悪いとビデオSN比が低下した
りする磁気記録媒体においては、磁性層表面をで
きるだけ平滑にすることのできる結合剤成分を使
用することが望まれる。
現在使用されている各種結合剤樹脂のうち、ポ
リビニルブチラールは、特に磁性粉末の分散性お
よび充填性を優れるものとして知られており（特
公昭51−31484号）、さらにポリビニルブチラール
と従来一般に使用されているポリエステル樹脂と
を併用したもの（特開昭52−113205号）や、スル
ホン酸金属塩基を含有する共重合ポリエステル樹
脂を結合剤成分として使用するもの（特開昭54−
28603号）が提案されている。
〔発明が解決しようとする問題点〕
ところが、結合剤成分としてポリビニルブチラ
ールを単独で使用したものは、磁性粉末の分散性
および充填性に優れるものの必ずしも満足できる
ものではなく、また磁性層の表面平滑性もそれほ
ど良好でなく、一般に柔軟性に欠け基体との接着
性に劣る。また、ポリビニルブチラールと従来一
般に使用されているポリエステル樹脂とを併用し
たものは、ポリビニルブチラールを単独で使用し
た場合の磁性層の柔軟性を改善して耐久性を向上
することはできるが、磁性粉末の分散性および充
填性はいまひとつ充分でなく、耐溶剤性も充分に
良好でない。さらに、スルホン酸金属塩基を含有
する共重合ポリエステル樹脂を結合剤成分の主成
分として使用したものは、磁性粉末の分散性、充
填性に優れるものの、耐久性に劣り、耐溶剤性お
よび基体との接着性もいまひとつ充分でない。
〔問題を解決するための手段〕
この発明者等は、かかる欠点を改善するため
種々検討を行つた結果 結合剤成分としてポリビ
ニルブチラールとスルホン酸金属塩基を含有する
共重合ポリエステル樹脂とを併用すると、磁性粉
末の分散性および充填性に優れ、かつ表面平滑性
および基体との接着性に優れた磁性層を有する磁
気記録媒体が得られることを見いだしたが、同時
に耐久性および耐溶剤性に劣り、記録再生時に磁
気ヘツドと激しく摺接すると磁性層が摩耗されて
磁気ヘツドの目づまりを生じたり、磁性層表面が
有機溶剤に犯され易いなどの難点があることも判
明した。
この発明はかかる知見に基づいて、さらに研究
を続けた結果なされたもので、ポリビニルブチラ
ールとスルホン酸金属塩基を含有する共重合ポリ
エステル樹脂とを併用したものに、さらに三官能
性低分子量イソシアネート化合物を加えたものを
結合剤成分として使用することによつて、磁性粉
末の分散性および充填性を充分に向上させ、かつ
磁性層の表面平滑性および基体との接着性を充分
に向上させるとともに、耐久性および耐溶剤性を
も充分に向上させたものである。
この発明において使用されるポリビニルブチラ
ールは特に磁性粉末の分散性に優れる樹脂で、現
在市販されているものがいずれも使用できるが、
ポリビニルアルコールとして10〜40モル％に相当
する水酸基含量を有し、平均重合度が約200〜
1000程度のものが好ましく用いられる。具体例と
しては、たとえば積水化学社製エスレツクBLS、
エスレツクBMS、エスレツクBM−２、ヘキス
トジヤパン社製モビタールＢ、電気化学工業社製
デンカブチラール＃3000Kなどが挙げられる。
上記ポリビニルブチラールと併用されるスルホ
ン酸金属塩基を含有する共重合ポリエステル樹脂
は、ポリエステル樹脂中に、５−ナトリウムスル
ホイソフタル酸、５−カリウムスルホイソフタル
酸、２−ナトリウムスルホテレフタル酸、２−カ
リウムスルホテレフタル酸などのスルホン酸金属
塩基を含有する成分を共重合して得られるもの
で、たとえば反応容器にジメチルテレフタレー
ト、ジメチルイソフタレートなどの酸成分、エチ
レングリコール、ネオペンチルグリコールなどの
グリコール成分、５−ナトリウムスルホイソフタ
ル酸などのスルホン酸金属塩基を含有するジカル
ボン酸成分などをその他の必要成分とともにそれ
ぞれ所定量加えてエステル交換反応を行い、次い
でセバシン酸、アジピン酸などを加えて反応させ
た後、減圧下で重縮合反応を行うことによつてつ
くられる。このスルホン酸金属塩基を含有する共
重合ポリエステル樹脂は従来のポリエステル樹脂
とちがつてポリビニルブチラールとの相溶性がよ
く、また空孔率が非常に低くて磁性粉末との親和
性もよいため磁性粉末を分散性よく高密度で充填
することができ磁性粉末の分散性および充填性を
一段と向上する。さらにこの共重合ポリエステル
樹脂は柔軟性に富み、磁性層表面の平滑性をも向
上する。
ポリビニルブチラールに対するスルホン酸金属
塩基を含有する共重合ポリエステル樹脂の使用割
合は、重量比で70対30〜98対２の範囲にするのが
好ましく、スルホン酸金属塩基を含有する共重合
ポリエステル樹脂の使用割合が少なすぎると所期
の効果が得られず、多すぎるとポリビニルブチラ
ールとの相溶性がなくなり良好な磁性層を形成で
きない。
この発明で併用される三官能性低分子量イソシ
アネート化合物は、通常１モルのトリオールと３
モルのジイソシアネートとを反応させて得られる
化合物で、このイソシアネート化合物中に含まれ
る三官能のイソシアネート基がポリビニルブチラ
ールに含まれるOH基およびスルホン酸金属塩基
を含有するポリエステル樹脂中に含まれるOH基
と反応して網状に架橋結合するため、磁性層の強
度が強くなり耐久性が向上する。具体例として
は、たとえば日本ポリウレタン工業社製コロネー
トＬ、バイエル社製デスモジユールＬ、武田薬品
工業社製タケネートD102などが挙げられる。使
用量は結合剤成分全量に対し５〜20重量％の範囲
内で使用するのが好ましく、20重量％を越えると
架橋密度が高くなつて磁性層を硬くし、脆くする
おそれがあり、また５重量％以下の量では所期効
果が得られない。
この発明に使用する磁性粉末としては、たとえ
ば、γ−Fe2O3粉末、Fe3O4粉末、Co含有γ−
Fe2O3粉末、Co含有Fe3O4粉末、CrO2粉末の他、
Fe粉末、Co粉末などの金属粉末など従来公知の
各種磁性粉末が広く包含される。
又、有機溶剤としては、シクロヘキサノン、メ
チルエチルケトン、テトラヒドロフラン、ジオキ
サン、ジメチルホルムアミドなどを単独もしくは
混合して用いるか、あるいはこれらの溶剤とメチ
ルイソブチルケトン又はトルエン等との混合溶剤
を用いればよい。
この発明の磁気記録媒体を製造するためには常
法に準じて行えばよく、たとえばポリエステルフ
イルムなどの基体上に、磁性粉末、ポリビニルブ
チラールとスルホン酸金属塩基を含有する共重合
ポリエステル樹脂と三官能性低分子量イソシアネ
ート化合物とからなる結合剤成分、有機溶剤およ
びその他の添加剤を含む磁性塗料を吹付けもしく
はロール塗りなどの任意の手段で塗布し、乾燥す
ればよい。
〔実施例〕
次に、この発明の実施例について説明する。な
お、以下において単に部とあるのは重量部を示
す。
実施例 １
温度計、撹拌機および部分還流式冷却器を具備
した反応容器にジメチルフタレート175部、ジメ
チルイソフタレート78部、エチレングリコール
161部、ネオペンチルグリコール145部、５−ナト
リウムスルホイソフタル酸ジメチル14.8部、酢酸
亜鉛0.17部、酢酸ナトリウム0.02部および三酸化
アンチモン0.16部を加え、140〜220℃で３時間エ
ステル交換反応を行なつた。次いでセバシン酸
131部を加え210〜250℃で１時間反応させたのち
反応系を60分間かけて１〜５mmHgまで減圧し、
さらに250℃で0.1〜0.3mmHgの減圧下で60分間重
縮合反応を行なつて、スルホン酸ナトリウム基を
含有する共重合ポリエステル樹脂を得た。このス
ルホン酸ナトリウム基を含有する共重合ポリエス
テル樹脂を使用し、
Co含有磁性粉末 600部
エスレツクBLS（積水化学社製、ポリビニルブチ
ラール） 100〃
スルホン酸ナトリウム基を含有する共重合ポリエ
ステル樹脂 20〃
コロネートＬ（日本ポリウレタン工業社製、三官
能性低分子量イソシアネート化合物） 10〃
カーボンブラツク 24〃
α−Fe2O3 12〃
シクロヘキサノン 500〃
トルエン 500〃
の組成からなる混合物をボールミル中で72時間混
合分散して磁性塗料を調整した。この磁性塗料を
厚さ15μのポリエステルフイルム上に乾燥厚が5μ
となるように塗布、乾燥し、表面処理を行つた後
所定の巾に裁断してビデオテープをつくつた。
実施例 ２
実施例１における磁性塗料の組成において、コ
ロネートＬの使用量を10部から15部に変更した以
外は実施例１と同様にしてビデオテープをつくつ
た。
比較例 １
実施例１における磁性塗料の組成において、コ
ロネートＬを省いた以外は実施例１と同様にして
ビデオテープをつくつた。
比較例 ２
実施例１における磁性塗料の組成において、エ
スレツクBLSを省き、スルホン酸ナトリウム基
を含有する共重合ポリエステル樹脂の使用量を20
部から110部に変更し、コロネートＬの使用量を
10部から20部に変更した以外は、実施例１と同様
にしてビデオテープをつくつた。
比較例 ３
実施例１における磁性塗料の組成において、ス
ルホン酸ナトリウム基を含有する共重合ポリエス
テル樹脂を省き、エスレツクBLSの使用量を100
部から110部に変更し、コロネートＬの使用量を
10部から20部に変更した以外は、実施例１と同様
にしてビデオテープをつくつた。
比較例 ４
実施例１における磁性塗料の組成において、ス
ルホン酸ナトリウム基を含有する共重合ポリエス
テル樹脂に代えて、バイロン200（東洋紡社製、ポ
リエステル樹脂、スルホン酸ナトリウム基を含有
せず）を同量使用した以外は、実施例１と同様に
してビデオテープをつくつた。
各実施例および比較例で得られた各ビデオテー
プについて、残留磁束密度（Br）、角型比（Br／
Bm）、クロマ出力およびビデオSN比を測定し、
低温スチール特性、耐久性、耐溶剤性および接着
性を試験した。クロマ出力およびビデオSN比は、
得られたビデオテープをビデオデツキ（日立製作
所社製VT−3000）に装填して記録再生を行い、
シンクロスコープおよびシバソク社製カラービデ
オノイズメーター925Cで測定した。また低温ス
チール特性試験は５℃、60％RHの条件下で、６
時間保存後、この条件下で再生し、出力が初期出
力より15dB以上低下するまでの時間を測定して
行ない、耐久性試験はビデオデツキを用いて得ら
れた各ビデオテープを3.3cm／secの走行速度で
100回走行させ、磁気ヘツドの目づまり状態を観
察して行なつた。又耐溶剤性試験はテトラヒドロ
フランを浸したテイツシユペーパーで各ビデオテ
ープの磁性層表面を数回こすり、そのときの磁性
層表面の状態を観察して行ない、磁性層表面が全
く犯されない場合を（〇）、わずかに犯される場
合を（△）として評価した。さらに接着性試験は
磁性層の表面に粘着テープを貼りつけ、全面に均
一に接着させた後瞬間的に引き剥がしたときの状
態を観察して行ない、磁性層が基体からほとんど
剥離されない場合を（〇）、若干剥離された場合
を（△）、剥離された場合を（×）として評価し
た。
下表はその結果である。
[Industrial Application Field] The present invention relates to a magnetic recording medium, and more specifically, it has excellent dispersibility and filling properties of magnetic powder, excellent surface smoothness of the magnetic layer, and excellent adhesion to a substrate, as well as durability and durability. This invention relates to a magnetic recording medium with excellent solvent properties. [Prior Art] Magnetic recording media are usually made by applying a magnetic paint consisting of magnetic powder, a binder component, an organic solvent, and other necessary components onto a substrate such as a polyester film, and drying the coating. The binder component used in this case has excellent dispersibility and filling properties of the magnetic powder, improves the surface smoothness of the magnetic layer, and provides the magnetic recording medium with excellent electrical properties such as a high signal-to-noise ratio. , it is necessary to select a material that has excellent adhesion to the substrate, as well as excellent durability and solvent resistance.Especially in products such as video tapes, where the electrical properties greatly depend on the smoothness of the magnetic layer surface, the magnetic layer In magnetic recording media where poor surface smoothness may result in a decrease in video S/N ratio, it is desirable to use a binder component that can make the surface of the magnetic layer as smooth as possible. Among the various binder resins currently in use, polyvinyl butyral is known to have particularly excellent dispersibility and filling properties for magnetic powder (Japanese Patent Publication No. 51-31484). (Japanese Unexamined Patent Publication No. 113205/1989), and those using a copolyester resin containing a sulfonic acid metal base as a binder component (Japanese Unexamined Patent Publication No. 113205/1983).
No. 28603) is proposed. [Problems to be Solved by the Invention] However, although the use of polyvinyl butyral alone as a binder component has excellent dispersibility and filling properties of the magnetic powder, it is not always satisfactory, and the surface smoothness of the magnetic layer is poor. Its properties are also not very good, and it generally lacks flexibility and has poor adhesion to substrates. In addition, the combination of polyvinyl butyral and commonly used polyester resin can improve the flexibility and durability of the magnetic layer compared to when polyvinyl butyral is used alone, but magnetic powder The dispersibility and filling properties of these materials are not sufficient, and the solvent resistance is also not sufficiently good. Furthermore, although copolyester resins containing sulfonic acid metal bases are used as the main binder component, they have excellent magnetic powder dispersibility and filling properties, but are inferior in durability, solvent resistance, and compatibility with the substrate. Adhesion is also not quite sufficient. [Means for Solving the Problem] The inventors have conducted various studies to improve these drawbacks. As a result, when polyvinyl butyral and a copolymerized polyester resin containing a sulfonic acid metal base are used together as a binder component, It has been discovered that a magnetic recording medium having a magnetic layer with excellent dispersibility and filling properties of magnetic powder, and excellent surface smoothness and adhesion to the substrate can be obtained, but at the same time, it has poor durability and solvent resistance. It has also been found that there are drawbacks such as the magnetic layer being abraded and clogging the magnetic head due to violent sliding contact with the magnetic head during recording and reproduction, and the surface of the magnetic layer being easily attacked by organic solvents. This invention was made as a result of further research based on such knowledge, and was made by combining polyvinyl butyral and a copolymerized polyester resin containing a sulfonic acid metal base, and further adding a trifunctional low molecular weight isocyanate compound. By using the additive as a binder component, the dispersibility and filling properties of the magnetic powder can be sufficiently improved, the surface smoothness of the magnetic layer and the adhesion with the substrate can be sufficiently improved, and the durability can be improved. It also has sufficiently improved properties and solvent resistance. The polyvinyl butyral used in this invention is a resin that has particularly excellent dispersibility for magnetic powder, and any currently commercially available polyvinyl butyral can be used.
It has a hydroxyl group content equivalent to 10-40 mol% as polyvinyl alcohol, and an average degree of polymerization of about 200-40%.
A number of about 1000 is preferably used. As a specific example, for example, Sekisui Chemical Co., Ltd.'s ESLETSUKU BLS,
Examples include Eslec BMS, Eslec BM-2, Mobital B manufactured by Hoechst Japan Co., Ltd., and Denka Butyral #3000K manufactured by Denki Kagaku Kogyo Co., Ltd. The copolymerized polyester resin containing a sulfonic acid metal base used in combination with the above polyvinyl butyral contains 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 2-potassium sulfoisophthalic acid, and 2-potassium sulfoisophthalic acid. It is obtained by copolymerizing components containing sulfonic acid metal bases such as terephthalic acid. For example, in a reaction vessel, acid components such as dimethyl terephthalate and dimethyl isophthalate, glycol components such as ethylene glycol and neopentyl glycol, and 5- A predetermined amount of a dicarboxylic acid component containing a sulfonic acid metal base such as sodium sulfoisophthalate is added together with other necessary components to perform a transesterification reaction, and then sebacic acid, adipic acid, etc. are added and reacted, and then the mixture is heated under reduced pressure. It is produced by performing a polycondensation reaction below. Unlike conventional polyester resins, this copolymerized polyester resin containing sulfonic acid metal bases has good compatibility with polyvinyl butyral, and also has a very low porosity and good affinity with magnetic powder, so it can be used as a magnetic powder. can be packed with good dispersibility and high density, further improving the dispersibility and filling properties of magnetic powder. Furthermore, this copolymerized polyester resin is highly flexible and improves the smoothness of the surface of the magnetic layer. The ratio of copolyester resin containing sulfonic acid metal base to polyvinyl butyral is preferably in the range of 70:30 to 98:2 by weight, and the use of copolymerized polyester resin containing sulfonate metal base is preferable. If the ratio is too small, the desired effect will not be obtained, and if the ratio is too large, the compatibility with polyvinyl butyral will be lost, making it impossible to form a good magnetic layer. The trifunctional low molecular weight isocyanate compound used in combination in this invention is usually 1 mol of triol and 3
A compound obtained by reacting mol of diisocyanate with the trifunctional isocyanate group contained in this isocyanate compound with the OH group contained in polyvinyl butyral and the OH group contained in the polyester resin containing a sulfonic acid metal group. Because they react and crosslink in a network, the strength of the magnetic layer becomes stronger and its durability improves. Specific examples include Coronate L manufactured by Nippon Polyurethane Industries, Desmodyur L manufactured by Bayer, and Takenate D102 manufactured by Takeda Pharmaceutical Company. The amount used is preferably within the range of 5 to 20% by weight based on the total amount of binder components. If the amount is less than % by weight, the desired effect cannot be obtained. Examples of the magnetic powder used in this invention include γ-Fe 2 O 3 powder, Fe 3 O 4 powder, and Co-containing γ-
In addition to Fe 2 O 3 powder, Co-containing Fe 3 O 4 powder, CrO 2 powder,
Various conventionally known magnetic powders such as metal powders such as Fe powder and Co powder are widely included. Further, as the organic solvent, cyclohexanone, methyl ethyl ketone, tetrahydrofuran, dioxane, dimethylformamide, etc. may be used alone or in combination, or a mixed solvent of these solvents and methyl isobutyl ketone, toluene, etc. may be used. In order to produce the magnetic recording medium of the present invention, it may be carried out according to a conventional method. For example, magnetic powder, a copolymerized polyester resin containing polyvinyl butyral and a sulfonic acid metal base, and a trifunctional A magnetic paint containing a binder component consisting of a low molecular weight isocyanate compound, an organic solvent and other additives may be applied by any means such as spraying or roll coating, and dried. [Example] Next, an example of the present invention will be described. In the following, parts simply refer to parts by weight. Example 1 175 parts of dimethyl phthalate, 78 parts of dimethyl isophthalate, and ethylene glycol were added to a reaction vessel equipped with a thermometer, a stirrer, and a partial reflux condenser.
Add 161 parts of neopentyl glycol, 145 parts of neopentyl glycol, 14.8 parts of dimethyl 5-sodium sulfoisophthalate, 0.17 parts of zinc acetate, 0.02 parts of sodium acetate, and 0.16 parts of antimony trioxide, and conduct a transesterification reaction at 140 to 220°C for 3 hours. Ta. Then sebacic acid
After adding 131 parts and reacting at 210 to 250°C for 1 hour, the reaction system was depressurized to 1 to 5 mmHg over 60 minutes.
Further, a polycondensation reaction was carried out at 250° C. under a reduced pressure of 0.1 to 0.3 mmHg for 60 minutes to obtain a copolymerized polyester resin containing sodium sulfonate groups. Using this copolymerized polyester resin containing sodium sulfonate groups, 600 parts of Co-containing magnetic powder Eslec BLS (manufactured by Sekisui Chemical Co., Ltd., polyvinyl butyral) 100〃 Copolymerized polyester resin containing sodium sulfonate groups 20〃 Coronate L (Trifunctional low molecular weight isocyanate compound manufactured by Nippon Polyurethane Industries Co., Ltd.) A mixture consisting of 10〃 carbon black 24〃 α-Fe 2 O 3 12〃 cyclohexanone 500〃 toluene 500〃 was mixed and dispersed in a ball mill for 72 hours. Adjusted magnetic paint. This magnetic paint is applied to a 15μ thick polyester film to a dry thickness of 5μ.
After coating, drying, and surface treatment, the tape was cut to a predetermined width to make a videotape. Example 2 A videotape was made in the same manner as in Example 1, except that the amount of Coronate L used in the composition of the magnetic paint was changed from 10 parts to 15 parts. Comparative Example 1 A videotape was made in the same manner as in Example 1 except that Coronate L was omitted from the composition of the magnetic coating material in Example 1. Comparative Example 2 In the composition of the magnetic paint in Example 1, Eslec BLS was omitted, and the amount of copolymerized polyester resin containing sodium sulfonate groups was reduced to 20%.
The amount of Coronate L used was changed from 110 parts to 110 parts.
A videotape was made in the same manner as in Example 1, except that the number of copies was changed from 10 to 20. Comparative Example 3 In the composition of the magnetic paint in Example 1, the copolyester resin containing sodium sulfonate groups was omitted, and the amount of Eslec BLS used was reduced to 100%.
The amount of Coronate L used was changed from 110 parts to 110 parts.
A videotape was made in the same manner as in Example 1, except that the number of copies was changed from 10 to 20. Comparative Example 4 In the composition of the magnetic paint in Example 1, in place of the copolymerized polyester resin containing sodium sulfonate groups, the same amount of Vylon 200 (manufactured by Toyobo Co., Ltd., polyester resin, not containing sodium sulfonate groups) was used. A videotape was made in the same manner as in Example 1, except that the following materials were used. For each videotape obtained in each example and comparative example, residual magnetic flux density (Br), squareness ratio (Br/
Bm), measure chroma output and video signal to noise ratio,
Tested for low temperature steel properties, durability, solvent resistance and adhesion. Chroma output and video signal to noise ratio are
The obtained videotape was loaded into a video deck (VT-3000 manufactured by Hitachi, Ltd.) and recorded and played back.
Measurements were made using a synchroscope and Shibasoku Color Video Noise Meter 925C. In addition, the low temperature steel property test was conducted under the conditions of 5℃ and 60%RH.
After time storage, the videotape was played under these conditions and the time required for the output to drop by 15dB or more from the initial output was measured.The durability test was performed by running each videotape obtained using a video deck at a speed of 3.3cm/sec. at speed
It was run 100 times and the state of clogging of the magnetic head was observed. The solvent resistance test was carried out by rubbing the surface of the magnetic layer of each videotape several times with tissue paper soaked in tetrahydrofuran and observing the condition of the surface of the magnetic layer at that time. 〇), cases where the violation was slightly violated were evaluated as (△). Furthermore, the adhesion test was carried out by attaching an adhesive tape to the surface of the magnetic layer and observing the state when it was peeled off instantly after it was adhered uniformly to the entire surface. 〇), cases where some peeling occurred were evaluated as (△), and cases where peeling occurred were evaluated as (x). The table below shows the results.
【表】
上表から明らかなように、この発明で得られた
ビデオテープ（実施例１および２）は比較例１な
いし４で得られたビデオテープに比して低温スチ
ール特性がよく、比較例１および２で得られたビ
デオテープに比し、耐久性および耐溶剤性がいず
れも良好で、比較例３および４で得られたビデオ
テープに比して、残留磁束密度、角型比、クロマ
出力、ビデオSN比がいずれも高く、さらに比較
例２および３で得られたビデオテープに比し、接
着性も良好で、このことからこの発明によつて得
られる磁気記録媒体は磁性粉末の分散性、充填性
および磁性層の表面平滑性に優れ、さらに接着性
に優れるとともに耐久性および耐溶剤性が改善さ
れていることがわかる。[Table] As is clear from the above table, the videotapes obtained in the present invention (Examples 1 and 2) have better low-temperature steel characteristics than the videotapes obtained in Comparative Examples 1 to 4, and Compared to the video tapes obtained in Comparative Examples 1 and 2, both durability and solvent resistance are better, and compared to the video tapes obtained in Comparative Examples 3 and 4, the residual magnetic flux density, squareness ratio, and chroma are better. Both the output and the video S/N ratio are high, and the adhesion is also better than that of the video tapes obtained in Comparative Examples 2 and 3. Therefore, the magnetic recording medium obtained by the present invention has a dispersion of magnetic powder. It can be seen that the magnetic layer has excellent properties such as hardness, filling properties, and surface smoothness of the magnetic layer, as well as excellent adhesiveness and improved durability and solvent resistance.
Claims (1)
スルホン酸金属塩基を含有する共重合ポリエステ
ル樹脂と、三官能性低分子量イソシアネート化合
物とが含まれてなる磁性層を有する磁気記録媒
体。 ２ ポリビニルブチラールと、スルホン酸金属塩
基を含有する共重合ポリエステル樹脂とが、ポリ
ビニルブチラール対スルホン酸金属塩基を含有す
る共重合ポリエステル樹脂の重量比で、70対30〜
98対２の範囲で含まれてなる特許請求の範囲第１
項記載の磁気記録媒体。[Claims] 1. Polyvinyl butyral as a binder component,
A magnetic recording medium having a magnetic layer comprising a copolyester resin containing a sulfonic acid metal base and a trifunctional low molecular weight isocyanate compound. 2 The polyvinyl butyral and the copolymerized polyester resin containing the sulfonic acid metal base have a weight ratio of polyvinyl butyral to the copolymerized polyester resin containing the sulfonic acid metal base from 70 to 30.
Claim 1 falling within the range of 98:2
Magnetic recording medium described in Section 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15109679A JPS5674823A (en) | 1979-11-20 | 1979-11-20 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15109679A JPS5674823A (en) | 1979-11-20 | 1979-11-20 | Magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5674823A JPS5674823A (en) | 1981-06-20 |
| JPH0234087B2 true JPH0234087B2 (en) | 1990-08-01 |
Family
ID=15511240
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15109679A Granted JPS5674823A (en) | 1979-11-20 | 1979-11-20 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5674823A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5841436A (en) * | 1981-09-03 | 1983-03-10 | Tdk Corp | Magnetic recording medium |
| JPS595424A (en) * | 1982-07-01 | 1984-01-12 | Sony Corp | Magnetic recording medium |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52113205A (en) * | 1976-03-18 | 1977-09-22 | Hitachi Maxell | Magnetic recording material |
| JPS5428603A (en) * | 1977-08-05 | 1979-03-03 | Toyo Boseki | Magnetic recording medium |
| JPS5433005A (en) * | 1977-08-18 | 1979-03-10 | Hitachi Maxell | Magnetic recording medium |
-
1979
- 1979-11-20 JP JP15109679A patent/JPS5674823A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52113205A (en) * | 1976-03-18 | 1977-09-22 | Hitachi Maxell | Magnetic recording material |
| JPS5428603A (en) * | 1977-08-05 | 1979-03-03 | Toyo Boseki | Magnetic recording medium |
| JPS5433005A (en) * | 1977-08-18 | 1979-03-10 | Hitachi Maxell | Magnetic recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5674823A (en) | 1981-06-20 |
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