JPH02254624A - Video cassette tape - Google Patents

Abstract

PURPOSE:To improve electromagnetic conversion characteristics of a video tape for S-VHS by providing plural magnetic layers on a nonmagnetic base. CONSTITUTION:The double-layer tape provided with the plural magnetic layers on the nonmagnetic base is housed into a cassette half for the S-VHS video tape. The binder to be used for the video tape is exemplified by polyurethane having wear resistance. The double-layer tape which is improved in the respective characteristics of the upper layer for high-frequency range characteristics and the lower layer for low-frequency range characteristics is housed into the S-VHS cassette half and is subjected to a picture recording and reproducing with a VHS video deck and S-VHS video deck, by which the characteristics excellent in both the high-frequency range and the low-frequency range are obtd. with the respective decks.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a video cassette tape, particularly a video cassette which is suitably used as a 5-VHS video tape and also suitably used as a conventional VH3 video tape. Regarding tape.

[Background of the invention]

As is well known, home video has traditionally been VH.
There are two systems, the S system and the β system, and in recent years the 5-VHS system, which is an evolved standard of the VHS system, has appeared.

This 5-VH5 system consists of: (1) The frequency of the luminance signal of the video signal is 2.6 MHz higher than that of VHS. As a result, the range of recording frequencies has also increased by 1.6 times. (2) The color signal band has become wider, and the luminance signal has also become higher and has advantages such as being properly separated on the recording frequency.

This increases the horizontal resolution from 240 lines in the conventional VHS system to more than 400 lines in the 5-VHS system, allowing images to be expressed in even more detail.
Colors are now reproduced more vividly and without muddying.

In this way, the 5-VHS system has changed the recording frequency, so in order to record and play back with this system, it is necessary to
A video deck separate from the HS method is required, but only 5
-VHS video decks can also record and play back VHS format.

This is called upward compatibility or one-sided compatibility.

By the way, in a 5-VHS video deck, when a 5-VHS cassette is inserted, the S indicator on the deck lights up.

This has a detection hole in the cassette half, and when the deck detects this, it lights up. If you insert a general VHS video cassette, the S indicator will not light up and the deck will automatically install a general VHS video cassette.
You will be recording and playing back HS.

Now, various video tapes for 5-VHS have been proposed, but conventional video tapes for 5-VHS use either a single layer of magnetic powder for 5-VHS or a single layer of magnetite. It was either that.

[Purpose of the invention]

In view of these circumstances, the inventors of the present invention conducted various studies with the aim of providing an S-V HS video cassette tape that is superior to conventional ones. The inventors have discovered that the objective can be achieved by a multilayer tape consisting of a multilayer tape, and have arrived at the present invention.

[Structure of the Invention] That is, the gist of the present invention is a video cassette tape in which a multilayer tape comprising a plurality of magnetic layers provided on a non-magnetic support is housed in a cassette half on a 5-VHS video tape. It is something.

5-The dimensions and shape of a VHS videotape cassette are the same as those for regular VHS, but the only difference is-
As you can see, there is a hole with a diameter of about 4 mm at the bottom of the back of the cassette half, at the left end of the groove.

As already mentioned, the 5-VHS deck detects this hole and performs recording and playback in the 5-VHS mode.

The present inventor stored a multilayer tape consisting of a plurality of magnetic layers on a non-magnetic support in a cassette half for 5-Vl (S) having such a structure, and recorded it on a video deck for S-V HS. - When played back, not only are the brightness and color signals better than conventional 5-VNS video tapes, but these video tapes are also compatible with general VNS video tapes.
The present invention was made based on the discovery that it can also be used satisfactorily for HS applications.

Magnetic materials used in the videotape of the present invention include:
Co-γ-Fe, such as γ-Fe,03, Co-containing-Fe,03 or Co-coated-Fe,03, 0.
, Fe50. .

Oxide magnetic materials such as CO-containing Fe30a or Co-coated, Go-γ-Fe30Cry such as wF6304, and others such as Fe, Ni, Fe-Ni alloy, Fe
-Co alloy, Fe-N1-P alloy, Fe-N1-Co alloy, Fe-Mn-Zn alloy, Fe-Ni-Zn alloy, F
e-Co-N1-qr gold alloy Fe-Co-N1-P alloy, Co-P alloy, Co-Cr alloy etc. Fex Ni,
Examples include various ferromagnetic materials (powders) such as metal magnetic powders containing Co as a main component.

St is an additive to these metal magnetic materials.

Elements such as Cu, Zn, Al1, P, Mn%Cr, or compounds thereof may be included. Hexagonal ferrite such as barium ferrite, iron nitride, etc. are also used.

The binder used in the videotape of the present invention includes abrasion-resistant polyurethane.

It has strong adhesion to other materials, is mechanically strong to withstand repeated applied forces or bending, and has good abrasion and weather resistance.

Furthermore, if a cellulose resin and a vinyl chloride copolymer are used in combination with polyurethane, the dispersibility of the magnetic powder in the magnetic layer will be improved and its mechanical strength will be increased. However, if only the cellulose resin and the vinyl chloride copolymer are used, the layer becomes too hard, but this can be prevented by the presence of the above-mentioned polyurethane.

Usable cellulose resins include cellulose ether, cellulose inorganic acid ester, cellulose organic acid ester, and the like. The above polyurethane and vinyl chloride copolymers may be partially hydrolyzed. Preferable examples of the vinyl chloride copolymer include a copolymer containing vinyl chloride-vinyl acetate or a copolymer containing vinyl chloride-vinyl acetate-vinyl alcohol.

Phenoxy resins can also be used.

Phenoxy resin has advantages such as high mechanical strength, excellent dimensional stability, good heat resistance, water resistance, chemical resistance, and good adhesiveness.

These advantages are complementary to the above-mentioned 1/tan, and can significantly improve the stability of the physical properties of the magnetic recording medium over time.

Furthermore, in addition to the binders described above, mixtures of thermoplastic resins, thermosetting resins, reactive resins, and electron beam curable resins may be used.

In order to improve the durability of the magnetic layer of the videotape of the present invention, the magnetic paint can contain various hardening agents, such as isocyanates. Examples of aromatic incyanates include tolylene diisocyanate (TDI) and adducts of these incyanates with active hydrogen compounds, and the average molecular weight is lOO.
A range of 3,000 to 3,000 is preferred.

Examples of aliphatic incyanates include hexamethylene diisocyanate (HMDI) and adducts of these incyanates and active hydrogen compounds. Among these aliphatic incyanates and adducts of these isocyanates and active hydrogen compounds, those having a molecular weight in the range of 100 to 3,000 are preferred. Among the aliphatic incynates, non-alicyclic incynates and adducts of these compounds with active hydrogen compounds are preferred.

A dispersant is used in the magnetic paint used to form the magnetic layer, and additives such as a lubricant, an abrasive, a matting agent, an antistatic agent, etc. may be included as necessary. Dispersants used in the present invention include phosphoric acid esters, amine compounds, alkyl sulfates, fatty acid amides, higher alcohols, polyethylene oxides, sulfosuccinic acids, sulfosuccinic esters, known surfactants, and salts thereof. It is also possible to use salts of polymeric dispersants having negative organic groups (eg -COOH). These dispersants may be used alone or in combination of two or more. In addition, as lubricants, silicone oil, graphite, carbon black graft polymer, molybdenum disulfide, tungsten disulfide, lauric acid, myristic acid, monobasic fatty acids with 12 to 16 carbon atoms, and the total number of carbon atoms of the fatty acids are used. and the number of carbon atoms is 21
~23(I) Fatty acid esters (so-called waxes) made of monohydric alcohols can also be used.These lubricants are usually added in an amount of 0.2 to 20 parts by weight per 100 parts by weight of the binder. .

Commonly used abrasive materials include fused alumina, various types of alumina such as alpha alumina, silicon carbide, chromium oxide, corundum, artificial corantum, artificial diamond, garnet, emery (main ingredients: corundum and magnetite), etc. be done. These abrasives have an average particle size of 0.05 to 5μ
Shoulder size is used, particularly preferably 0.1~
2μ shoulder. These abrasives are added in an amount of 1 to 20 parts by weight based on 100 parts by weight of the binder.

As the matting agent, organic powder or inorganic powder may be used individually or in combination.

As the organic powder used in the present invention, acrylic styrene resin, benzoguanamine resin powder, melamine resin powder, and phthalocyanine pigment are preferable, but polyolefin resin powder, polyester resin powder, polyamide resin powder, and polyimide resin powder are preferable. Resin powder, polyfluoroethylene resin powder, etc. can also be used, and inorganic powders include silicon oxide, titanium oxide, aluminum oxide, calcium carbonate,
barium sulfate, zinc oxide, tin oxide, aluminum oxide,
Chromium oxide, silicon carbide, calcium carbide, α-Fe
Examples include z 03 , tar, kaolin, calcium sulfur, boron nitride, zinc fluoride, and molybdenum dioxide.

Antistatic agents include carbon black, graphite, conductive powders such as tin oxide-antimony oxide compounds, titanium oxide-tin oxide-antimony oxide compounds, natural surfactants such as saponin, alkylene oxides, and glycerin. nonionic surfactants such as glycidol-based, higher alkylamines, quaternary ammonium salts, pyridine, other heterocycles, cationic surfactants such as phosphonium or sulfonium; carboxylic acids, sulfonic acids, phosphoric acids, sulfuric acids Anionic surfactants containing acidic groups such as ester groups and phosphate ester groups; amino acids;
Examples include amphoteric activators such as aminosulfonic acids, sulfuric acid or phosphoric acid esters of amino alcohols, and the like.

The solvents to be added to the above paint or the diluting solvent when applying this paint include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketonon; alcohols such as methanol, ethanol, globanol, and butanol; if methyl, ethyl acetate; , esters such as butyl acetate, ethyl lactate, and ethylene glycol monoacetate; ethers such as glycol dimethyl ether, glycol monoethyl ether, dioxane, and tetrahydrofuran; aromatic hydrocarbons such as benzene, toluene, and xylene; methylene chloride, ethylene chloride, carbon tetrachloride, chloroform,
Halogenated hydrocarbons such as dichlorobenzene can be used.

Examples of the support include polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate and cellulose diacetate, and plastics such as polyamide and polycarbonate. However, Cu, A12. Metals such as Z ports, glass, ceramics such as boron nitride, Si carbide, etc. can also be used.

The thickness of these supports is about 3 to 100 μm in the case of a film or sheet, preferably 5 to 50 μm,
In the case of a disk or card, the thickness is about 30 μm to lOmra, and in the case of a drum, it is used in a cylindrical shape, and the shape is determined depending on the recorder used.

An intermediate layer for improving adhesion may be provided between the support and the magnetic layer.

Coating methods for forming the magnetic layer on the support include air knife coating, blade coating, air knife coating, squeeze coating, impregnation coating, reverse roll to 1-1 I-transfer roll coating, gravure coating, and kiss coating. , cast coat, spray coat,
Extrusion coats and the like can be used, but are not limited to these.

When constructing a magnetic layer on a support using these coating methods, there are two methods: one method involves stacking the coating and drying steps layer by layer (so-called wet-on-dry coating method), and the other method involves stacking the coating and drying steps layer by layer (so-called wet-on-dry coating method). There is a method in which layers are coated simultaneously or sequentially (so-called wet-on-wet method), but any method can be used in manufacturing the magnetic recording medium of the present invention.

Note that, without impairing the effects of the present invention, a nonmagnetic layer may be provided above and below or between the magnetic layers, or between the magnetic layers.

By such a method, the magnetic layer coated on the support is optionally treated to orient the ferromagnetic metal oxide powder in the layer, and then the formed magnetic layer is dried.

In this case, the orientation magnetic field is approximately 10 to 500 AC or DC.
The temperature is about 0 Gauss, the drying temperature is about 30 to 120°C, and the drying time is about 0.1 to 10 minutes. Further, the magnetic recording medium of the present invention is manufactured by subjecting it to surface smoothing treatment or cutting it into a desired shape, if necessary.

Next, the present invention will be explained with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

〔Example〕

Examples and Comparative Examples The magnetic paints for magnetic paint A [upper layer (second magnetic layer)] and magnetic paint B [lower layer (first magnetic layer)] having the compositions listed in Tables 1 and 2 were kneaded to form each. After the ingredients are well dispersed,
A magnetic paint for coating was prepared by adding 5 parts by weight of polyisocyanate (Coronate L, manufactured by Nippon Polyureta Kogyo Co., Ltd.).

Next, magnetic paints A and B were coated in multiple layers according to a conventional method and dried to produce a videotape.

The videotape thus obtained was placed in a 5-VHS cassette, and its electromagnetic conversion characteristics were measured.
.

The manufacturing conditions such as the layer structure of each videotape are shown in Table 3. Surface Layer Structure and Other Manufacturing Conditions The 5-VHS cassette half is provided with an S mode detection hole, but the general VH8 cassette half is not provided with an S mode detection hole. Therefore, in the case of nothing, Vl(S
This means that it is stored in a cassette half.

Table 4 Electromagnetic conversion characteristics of videotape> When recorded and played back using a VHS video deck.

*i When recorded and played back using a 5-VHS video deck.

Judgment criteria: O: Very good 0: Good Δ: Average Since magnetic powder with a high coercive force (Hc) is used to improve the magnetic field, the low frequency characteristics, especially the color signal, become slightly low. Ma! ;, The tape of Comparative Example 4, which is a conventional VHS tape, has S on the cassette.
Since there is no mode detection hole, even if a 5-VHS video deck is used, recording and playback can only be performed in the normal VHS format, so the characteristics are commonplace.

On the other hand, the tape of Comparative Example 3, in which a conventional VHS tape is stored in a 5-VHS upper cassette, uses magnetic powder with a low coercive force (Hc), so it cannot be played in S mode on a 5-VHS video deck. When recording and playing back, the high-frequency characteristics actually deteriorate.

Furthermore, the tape of Comparative Example 1, in which the multilayer tape was housed in a VHS cassette half, could not fully demonstrate its high-frequency characteristics because it could not be recorded or played back in S mode on a VHS video deck.

On the other hand, in Example 1 of the present invention, a multilayer tape with improved characteristics, the upper layer for high frequency characteristics and the lower layer for low frequency characteristics, is housed in a 5-VHS cassette half to create a VHS video deck. By recording and playing back on 5-VHS video decks, excellent high and low frequency characteristics were obtained on each deck.

〔Effect of the invention〕

The video cassette tape of the present invention not only has better electromagnetic conversion characteristics than conventional 5-VHS video tapes, but also can be used satisfactorily as a general VHS video tape.

Originator Konica Co., Ltd.

Claims (1)

[Claims] A video cassette tape comprising a multilayer tape comprising a plurality of magnetic layers provided on a non-magnetic support and housed in a cassette half for S-VHS video tape.