JPS58122620A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve durability by using modified polymers obtd. by graft polymerizing hydroxyl group-contg. polymerizable unsatd. compds. to polymer binders by irradiation of radiations as binders. CONSTITUTION:Radiations are irradiated to polymers such as vinyl chloride- vinyl acetate copolymers which produce free radicals when irradiated with radiations such as gammer rays, electron rays or the like, and compds. contg. hydroxyl groups such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate or the like are graft- polymerized, whereby modified polymers are obtained. Such polymers are used as binders for forming magnetic layers using magnetic powder.

Description

[Detailed Description of the Invention] This invention is directed to a magnetic recording medium, and is truly 1#.
Specifically, it concerns a durable magnetic recording medium for God's sake.

In order to increase the durability of the spherical medium, for example, a binder is used to improve @-114& with the magnetic powder, and as a result, the splitting property and filling property are improved, and the #broadness is reduced. is used. In such a method, it has been proposed to add a copolymer component of the binder and modify it to improve the adhesion of the binder to the magnetic powder. However, in such a method, all of the copolymerization components have to have a polymerization ability of 1, and even if the seven limits are (N), the relative plate size is not suitable for this case. Otherwise, it would be difficult to have a violet block, or the block would become a block type, and the use of C1 would be always restricted, and 60,000 yen would be industrially limited. Application 1 Iflta is small and it is not suitable for rice use.

Therefore, this invention is based on the use of modified poly-7 as a binder to produce durable magnetic recording media.

The modified polymer binder used in this invention can be obtained by irradiating a conventional polymer used as a binder for cod porridge with radiation, which causes the electrolytic unsaturated compound containing hydroxyl groups to become graft-like. Such a binder is obtained by first irradiating a polymer undergoing graft polymerization with gamma radiation, monomer radiation, etc. to generate organic free radicals, and then converting the free radicals into organic free radicals. It is obtained by polymerizing a monomer containing a hydroxyl group and an unsaturated compound.

Therefore, any polymer that can be conveniently used as a binder in the present invention may be used as long as it produces free 2 radicals when irradiated with radiation and disintegrates when irradiated with radiation. 'H&,'N'Fung is that the use of radiation with a large amount of penetration will invariably generate free radicals, and even polymers that disintegrate depending on the dose of such radiation can be irradiated with Jin's method is useful because irradiating the JR women at reduced doses under suboptimal conditions can generate enough free radicals to react with the water-rich monomers. The circumference of the axis for release will be much wider. Polymers that can be used in the above-mentioned method preferably have a molecular weight of about 10,000 to 100,000, such as vinyl chloride-vinyl acetate co-merchandising, vinyl bottle-vinyl propionate co-articulate polymers. , weird vinyl-vinegar acupuncture vinyl-vinyl alcohol co-polymer, ffl-formed vinyl-vinyl gropionate-vinyl alcohol co-polymer, vinyl chloride-vinyl acetate-maleic acid co-polymer, vinyl chloride-vinyl chloride IJ-dene copolymer Combined, fused vinyl-acrylonitrile co-IL8, acryl-nystyl-acrylonitrile co-IL8, f-acrylic ester single-layered vinylidene co-combined, methacryl-dissociated ester-formed vinylidene co-Iris 6+, methacryl-nystyl-acrylonitrile co-IL Great price, silent mouth J' [Polyurethane * M
W, phenoxy compound, polyvinyl fluoride, bottled vinylidene-acrylonitrile conjugate, butadiene-acrylonitrile conjugate, acrylonitrile-butadiene-acrylic modified conjugate, acrylo-tolyl-butadiene-methacrylic mxm compound , polyvinyl butyral, cellulose derivative, styrene-butadiene combination, polyester resin, ) L-Nol resin, epoxy resin, thermosetting polyurethane resin, urine resin, melamine resin, alkyd 6
1) Examples include urea-formaldehyde, urea-formaldehyde, or a mixture thereof.

In addition, as the radiation irradiated to generate free radicals in the polymer as described above, for example, comma-
The radiation dose is approximately 0.1.
It is preferably in the range of ~101Vlrad.

In addition, as a compound containing a polymer binder treated with the above-mentioned radiation and combined with a polymer binder carrying #R group, monomerization 111
-4fL and water should be 1- to 1- to turnip, and the following general formula (1): % formula % [In the formula, river means a hydrogen atom or a methyl group, and bird means formula-(C1( 2) 01 (in the formula, m means 2 to 4 raised ridges), and the number of crabs in which n+p is 1 to 4 is represented by J[e]. It means an alkylene group represented by the following. Preferred such compounds include roxypropyl acrylate, 2-hydroxypropyl methacrylate, and the like. I don't know what to say.
The ratio of one Pestle polymer to the other is approximately u1.
or io* is preferable.

In addition, when this m-related relationship is not connected, the power and the 94 sex will no longer be strong. , and if there is too much dust, the metamorphosed Bolimano (to the rugged forest of Indah I91)
The quality of the song may become scary, or it may completely saponify, making it difficult to mix with the binder of the song. In addition, the viscosity becomes #IA4 when used as a liquid, making it unusable for large mackerel.

The above-mentioned ↓9 polymerizable unsaturated oro compound lIJ is preferably used as a polymer binder and is subjected to radiation treatment. This grafting method can also be carried out according to conventional methods.

The binder made of a modified polymer conveniently used in the present invention can be used in combination with the above-mentioned binder for sufficient effect. In situations where such a modified binder is used in combination with a fi-rich binder, desired seedlings can be expected if the modified binder weighs at least about 1 mu.

In addition, the modified polymer binder conveniently used in @Ming can be combined with a yarn combined with the multilayer isocyanate compound 1 or with the binder of the above-mentioned type. It may be combined with a total in-7-anate compound to form a thread that is thermoset and cut.

In addition, as the -Fe powder, any powder that is commonly used in FFI journals may be used, for example, 1-Fe powder.
2O3, Feρ4, r - # between Fe20B and Feρ4! Chemical mow iron, iron containing y -Fe2O3,C
o@Feρ4, γ-F'e203 and Fe3O containing
Iron oxide with an oxidation state intermediate to 4, those containing one or more metal elements (particularly transition metal element 1A) in the tJ oxidation group, and iron oxides mainly composed of 6 oxides or hydrates of the above iron oxides. CrO2, oxide-based magnetic powder such as Cr20B +1 formed by reducing the surface of CrO2, metals such as Fe1Co, Ni, etc.
-Co alloy, F'e-Ni alloy, Fe -Co -N
i alloy, Co-N1-P alloy, Co-Ni-1'e
-t$ combination, Fe -Ni -Zn synthesis, k'e
-Movement-mu-kettle, k'e -Co'-Ni -P
The foundations of the Jia Ei in the Zengka fi are amazing. In addition, the polymer binder 2 and the polymer binder made of pine wood according to the present invention also contain aluminum oxide, chromium oxide, silicon oxide, etc. as a binding material, carbon black, etc. as an anti-wound prevention material, and a lubricant. As niized molybdeno,
graphite, silicone oil, olive ill f
It can add cancer to the body.

In addition, examples of non-abrasive materials that form a cicada layer with the composition as described above include polyesters such as evaporated polyethylene terephthalate, polyolefins such as polypropylene, cellulose triacetate and cellulose diacetate. cellulose derivatives, such as
Examples include polycarbonate, polyvinyl chloride, polyimide, metals such as aluminum and copper, and non-magnetic materials such as paper.

In addition, bath additives that are useful for preparing magnetic paints include ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone; CDs such as methanol;
Alcohols esters such as ethyl acetate, butyl acetate, mgii ether; glycol ethers such as ethylene glycol dimethyl ether, ethylene glycol 7-ethyl ether, dioxane; 1 ml of swollen hydrocarbon IIA or a mixture thereof is applied.

The Ichikiki record peak body obtained by the method described above is
The magnetic powder has good dense layering properties on the base material of Kamiiso type, and the furrowing property and elemental property of the III type powder are also the same as above, and the durability is not so good.

Hereinafter, this invention will be explained with reference to Examples.

1 ffif polyurethane binder (product name "N-2")
304''; After forming the sheet into a sheet having a thickness of about 10 DIIm, it was irradiated with 5 Mrad of single-layer embroidery to obtain a monomorphic polyurethane binder.

Next, using this modified binder, an acupuncture needle with the following composition was prepared.

Modified polyurethane 1 [JU
'e20, 4υtJz Squalane 91 Cr2U5 4 #Methyl ethyl ketone 50Ll z Methyl isobutyl ketone SLILI #Knead the paint set tit- with the above composition M, add a batch of cicada, and apply this magnetic paint to a 16μ thick polyester base. It was applied onto a film to a thickness of 4 μm. This was dried and sterilized to make a magnetic tape.

Example 2 A magnetic tape was prepared in the same manner as in Example 1ξ by applying a material having the following composition to a polyester base film having a thickness of 16 μm to a thickness of 4 μm.

γ-Fe2O3 4 0 0 1L
xkh
Is it real JII except for using a polyurethane binder (product name "N-2304")? A magnetic tape was prepared in the same manner as No. 111.

A magnetic tape was prepared in the same manner as in Example 2 except that a non-modified polyurethane binder (trade name [N-25044)] was used instead of the 9'l12 modified polyurethane binder.

Regarding the magnetic tapes obtained in the above-mentioned Examples and Comparative Examples, b1 decoration, gloss, dustiness, and still were defined, and the results are shown in the table below.

From these findings, it has been found that the magnetic tape according to the present invention not only has better magnetic flux *# properties, but also has better intellectual properties than the magnetic tapes of soft examples.

Agent: Toshiki Sugiura (Voluntary) Written amendment to the proceedings Dear Commissioner of the Patent Office 1, Indication of the case Relationship to the Patent Application No. 4554 of 1982 Patent applicant 6-chome, Kitashinyo, Tokyo Parts Co., Ltd. No. 7, No. 35 (218) Sony Corporation 6, Amendment 1 The number of inventions is increased by 1 (1), and the scope of claims column of the specification is amended as shown in the attached sheet.

(2) In the 5th line from the bottom of the second specification, after the ``is.'', ``Also, a mixture of a general binder used as a binder for magnetic recording media and a polymerizable unsaturated compound containing a hydroxyl group is exposed to radiation. 0'', which can also be obtained by irradiation and graft polymerization.

Claims: A magnetic magnetomotive medium using as a binder a modified polymer obtained by graft polymerizing a polymerizable unsaturated compound containing a hydroxyl group to a polymer binder by irradiation with radiation.

Claims (1)

[Claims] The special feature is that a modified polymer is used as a binder by combining a polymer binder treated with radiation and treated with a hydroxyl group. body·