WO1989012295A1

WO1989012295A1 - Magnetic tape as information carrier

Info

Publication number: WO1989012295A1
Application number: PCT/HU1988/000040
Authority: WO
Inventors: László TÓTH
Original assignee: Radius Hungaricus Rt
Priority date: 1988-06-09
Filing date: 1988-06-09
Publication date: 1989-12-14
Also published as: EP0374155A1

Abstract

The invention relates to an information carrying magnetic tape comprising a magnetizable electric information carrying layer applied onto one side of the synthetic carrier layer. The essence of the invention lies in that in the synthetic carrier layer (1) glass fibres (4) running parallel with each other and the longitudinal direction of the magnetic tape are arranged, being coated with a synthetic coat (7) which is compatible with the material of the synthetic carrier layer (1).

Description

Magnetic tape as information carrier

The invention relates to a magnetic tape serving as an information carrier comprising a magnetizable electric information carrying layaer applied onto the synthetic carrier layer in a manner Known in itself.

As it is well known, the presently used magnetic tapes of different types, including the information carrying tapes on a synthetic basis used with magnetophons, memories of computers, video recorders etc. are formed so, that they contain synthetic carriers planned and dimensioned fundamentally for mechanical stresses, onto which a layer for storing electric signals resp. informations made of a metal oxyde, e.g. Fe₂O₃ or chromdioxyde used to be applied.

Known information carrying magnetic tapes suffer, however, remanent deformations on the effect of mechanical stresses, so e.g. due to forward-and reverse reeling with a high velocity, in course of signal search etc. appearing mainly in longitudinal elongation, resulting in course of further use distortion in signal reproduction or in search for signals.

Another disadvantageous feature lies in - it can be well observed with known magnetic tapes - that the synthetic carrier layer does not protect against external or interacting re-magnetization of the metal oxyde particles having been re-magnetized to a different extent. The aim of the invention was to develop an information carrying magnetic tape which is well protected as well against remanent elongation and demagnetization, as re-magnetization, and all the aims set can be realized so, that synthetic carrier layer and the information carrying layer thereon could be made from the same material, as having been used up to now. As a signal recording magnetic layer well known chromedioxyde or γ- Fe₂O₃ can be used.

The magnetic tape according to the invention does not suffer any remanent elongation, not even after an optionally long-life use, while information carrying particles are protected against external, in a given case pulsating HF-field of force and internal demagnetization.

Accordingly, the invention relates to an information carrying magnetic tape containing a magnetizable electric information carrying layer applied onto one side of the synthetic carrier layer, which can be characterized in that in the synthetic carrier layer, parallel to the longitudinal direction and one another glassfibres are arranged, which are provided with a coating made of a synthetic material being compatible with the material of the synthetic carrier layer.

With a preferred embodiment of the invention between the glassfibres polyamide fibres are - expediently alternating therewith - arranged.

It is considered as advantageous, if the diameter of the glass fibres amounts to 5-14 μm.

With a preferred embodiment 10 to 100 pcs glassfibres /mm are contained in the width of the synthetic carrier layer. The information carrying magnetic tape can be further characterized in that on the synthetic carrier layer lying opposite to the information carrying layer a metal layer in a thickness of 0,5-5 μm preventing demagnetization is applied, expediently by vacuum-vaporization. It is considered as advantageous, if the metal layer is Al, Cu or Ag.

With a further preferred embodiment of the invention a synthetic insulating layer is applied onto the metal layer externally.

According to a preferred mode of realization the insulating layer is applied by sintering in an eddy current bed.

The information carrying magnetic tape according to the invention meets the requirement, in so far as the synthetic materials used are compatible with glass and each other.

A furhter characteristic of the magnetic tape according to the invention lies in that the coat of the glassfibres is composed of an organic Si-compound and the aquaeous solution of polyvinyl acetate or a Cr-methyl-methacrylate derivate and the aquaeous solution of polyvinyl acetate or epoxycompatible double-bound aliphatic amine and the aquaeous solution of polyvinyl-acetate.

The information carrying magnetic tape will be de. scribed in detail by menas of some preferred embodiments and examples.

The accompanying drawing shows an embodiment of the magnetic tape according to the invention, serving as an example and illustrating the cross-sectional view.

The magnetic tape having been developed in accordance with the invention contains the synthetic carrier layer 1, which can be made from the most diverse materials, materials having been used up to now can be advantageously used for the solution according to the invention. The thickness of said synthetic carrier layer 1 lies in the range between 10 to 16 μm, optionally 12 and 14 μm. It is considered as advantageous to use polyamide, polyvinyl acetate or polyethylene terephtelate as the synthetic carrier layer 1.

In the synthetic carrier layer 1, parallel with each other and the longitudinal direction of the magnetic tape glassfibres 4 and polyamide fibres 5 are embedded, with the embodiment illustrated here they are arranged alternatively. Application of the polyamide fibre 5 can be omitted, at the same time glassfibres 4 form one of the most important characteristic of the invention. Expediently glassfibres 4 have a diameter in the range of 5 to 9 μm, preferably 5 to 7 μm and are arranged so, as to contain 10 to

100 glassfibres/mm in the cross-section of the magnetic tape. Polyamide fibres 5 may have the same diameter, as glassfibres 4, however, they may have different diameters. An arrangement is also possible, wherein two glassfibres 4 each are followed by one polyamide fibre 5, however, as already mentioned before, polyamide fibres 5 can be even omitted.

The information carrying layer 2 is applied onto the synthetic carrier layer 1 in a way known in itself, for this purpose ɣ- Fe₂O₃, chromedioxyde or any other suitable material can be used. Onto the synthetic carrier layer 1 lying opposite to the layer having been provided with the information carrying layer 2 the metal layer 3 made of Al, Cu or Ag is applied, preferably by vacuum vaporization. Thickness of said metal layer amounts preferably to 0,5 - 5 μm, advantageously 2-3 μm. A further insulating layer 5 is applied extrenally onto the metal layer 3, thickness of appliance amounts to at least two molecules. It is considered, as advantageous, if the insulating layer 6 is made of the same material, as the synthetic carrier layer 2, however, it may be different, the essence lies in that it should be compatible with the metal layer 3.

Metal layer 3 protects against demagnetization, glassfibres 4 prevent elongation, so by the simultaneous use of them a magnetic tape with a far better quality can be obtained.

To achieve properly stable position of the glassfibres they are coated with the coating 7, which may be an organic Si-compound and the aquaeous solution of polyvinyl acetate o r of Cr-methyl methacrylate derivate and the aquaeous solution of polyvinyl acetate or epoxy-compatible double-bound aliphatic amine and the aquaeous solution of polyvinyl acetate.

Example 1:

A magnetic tape consists of the following elementary layers: the insulating layer 6 made of polyurethane in a thickness corresponding to two molecules, the metal layer 3, of aluminium, applied in a thickness of 2 μm with vacuum-evaporization, the synthetic carrier layer 1 made of polyamide in a thickness of 12 μm, containing 20 pieces of glassfibre ∅ 7 μm/ mm width and coated with the mixture of an organic Si-compound and the aquaeous solution of polyvinyl acetate. The information carrying layer 2ɣ- Fe₂O₃ with polyvinyl acetate - is applied epitaxially.

Example 2:

As a metal layer 2 a 2 μm thick Ag-layer is applied, while as a synthetic carrier layer 1 polyvinyl acetate is used, containing 30 pcs glassfibres 4 with a diameter of 5 μm/mm, coated with the aquaeous solution of polyvinyl acetate and Cr-methyl-methacrylate, between the glassfibres 4 a poyamide fibre 5 eachis arranged, as information carrier layer 2 chromedioxyde is used, applied in a way known in itself.

Claims

What we claim :

1. Infromation carrying magnetic tape comprising a magnetizable electric information carrying layer applied onto one side of the synthetic carrier layer, c h a r a c t e r i z e d in that in the synthetic carrier layer (1) glassfibres (4) running parallel with each other and the longitudinal direction of the magnetic tape are arranged, being coated with a synthetic coat (7) which is com' patible with the material of the synthetic carrier layer (1) .

2. Information carrying magnetic tape as claimed in claim 1, c h a r a c t e r i z e d in that between the glassfibres (4) polyamide fibres (5) are arranged, preferably alternatively therewith.

3. infromation carrying magnetic tape as claimed in claim 1 or 2, c h a r a c t e i z e d in that glassfibres (4) have a diameter of 5 to 14 μm.

4. Information carrying magnetic tape, as claimed in any of the claims 1 to 3, c h a r a c t e r i z e d in that in the width of the synthetic carrier layer (1) 10 to 100 glassfibres (4) pro mm width are arranged.

5. Information carrying magnetic tape as claimed in any of the clams 1 to 4, c h a r a c t e r i z e d in that onto the synthetic carrier layer (1) lying opposite to the side having been coated with the information carrying layer (2) a metal layer (3) in the thickness of 0,5-5 μm is applied preferably by vacuum-evaporization for preventing demagnetization.

6. Information carrying magnetic tape as claimed in claim 5, c h a r a c t e r i z e d in that the metal layer (3) is Al, Cu or Ag.

7. Information carrying magnetic tape as claimed in claim 5 or 6, c h a r a c t e r i z e d in that a synthetic insulating layer (6) is applied externally onto the metal layer (3).

8. Information carrying magnetic tape as claimed in claim 7, c h a r a c t e r i z e d in that the insulating layer (6) is applied by sintering in an eddy current bed.

9. Information carrying magnetic tape as claimed in any of the claims 1 to 8, c h a r a c t e r i z e d in that the synthetic materials used are compatible with one another arvd glass.

10. Information carrying magnetic tape as claimed in any of the claims 1 to 9, c h a r a c t e r i z e d in that as a synthetic carrier layer polyamide, polyvinylacetate or polyethylene-terephtelate is used.

11. Information carrying magnetic tape as claimed in any of the claims 1 to 9, c h a r a c t e r i z e d in that coating (7) of the glassfibres (4) is the aquaeous solution of an organic Si-compound and polyvinyl acetate or the aquaeous solution of Cr-methyl-methacrylate derivate and polyvinyl acetate or epoxy-compatible double-bound aliphatic amine and the aquaeous solution of polyvinyl acetate.