WO1996002053A1 - Magnetic tape - Google Patents
Magnetic tape Download PDFInfo
- Publication number
- WO1996002053A1 WO1996002053A1 PCT/HU1995/000027 HU9500027W WO9602053A1 WO 1996002053 A1 WO1996002053 A1 WO 1996002053A1 HU 9500027 W HU9500027 W HU 9500027W WO 9602053 A1 WO9602053 A1 WO 9602053A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- magnetic tape
- glass fibres
- carrier layer
- layer
- plastic carrier
- 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.)
- Ceased
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
Definitions
- the invention relates to an information-carrying magnetic tape with improved properties, which contains a magnetizable electric information-carrying layer applied onto the one side of a plastic carrier layer in a manner known per ⁇ e , wherein parallel with the longitudinal axis of the magnetic tape glass fibres provided with a plastic coating compatible with the material of the plastic carrier layer are arranged in the plastic carrier layer.
- magnetic tapes of various kinds including also the plastic-base information-carrying tapes used in magnetophones (tape-recorders) , computer-recorders, video cassette recorders and similar equipments, are developed in such a manner that they contain a plastic carrying layer designed and sized for substantially mechanical stress, and the electric signal- and information-recording layer consisting of metal oxide, mostly gamma-ferric oxide and chromic oxide, is applied thereto.
- an information-carrying magnetic tape which contains a magnetizable electric information-carrying layer applied onto the one side of a plastic carrier layer wherein, in the plastic carrier layer, glass fibres provided with a plastic coating compatible with the material of the plastic carrier layer are arranged parallel with each other and the longitudinal axis of the magnetic tape.
- This magnetic tape eliminated the drawback of earlier known information-carrying magnetic tapes that, after a certain time, they suffered permanent deformation under effect of mechanical stress caused by high-speed winding and back-winding and above all, by a longitudinal elongation. During the further use this elongation induced a distortion both in the tracing as well as reproduction of signals.
- the magnetic tape according to the Hungarian patent specification referred to above eliminated also an other drawback of earlier known magnetic tapes, namely that their plastic carrier layer did not assure any protection to the metal oxide particles reverse-magnetized to varying extent against reverse magnetization of outer origin or between the particles themselves.
- a disadvantage of the magnetic tape according to the Hungarian patent specification referred to above is that the amount of circular-section glass fibres, which can specifically be utilized in the basal laminate, is low whereby the tensile strength of the tape is restricted.
- An other drawback of this tape is that, as a consequence of the low tensile stength of circular-section glass fibres, a continuous bulk production can be realized only difficultly and expensively.
- An additional disadvantage of this magnetic tape is that high-purity glass fibres being free from impurities, i.e. those produced from very expensive glass basic material, can only be used for its manufacture.
- the aim of the present invention is to eliminate the drawbacks of the known solutions and thereby to develop an information-carrier magnetic tape possessing more favourable tensile strength and rendering possible the utilization also of glass fibres prepared from highly contaminated cheap glass material.
- the invention is based on the recognition that the above aim can fully be achieved by arranging primary glass fibres of elongated elliptical ("flat") cross-section in the plastic carrier layer.
- the invention is furthermore based on the recognition that the flexibility of the tape is also increased in the case of glass fibres with elongated ellipse-form. This means that under the effect of a mechanical force occurring on bending, the glass fibre is not splitted out from the plastic coating material even in the case of a small bending radius ("strap effect") , which has a practical importance above all because of the permanent bending stress appearing on winding.
- a further basis of the invention is the recognition that the glass fibres of elongated elliptical cross-section may be prepared even from considerably contaminated cheap basic glass material without a perceptible decrease in the tensile strength of the primary glass fibres.
- An other basis of the invention is the recognition that the plastic film covering the surface of the glass fibres can be fixed to the surface of primary glass fibres of elongated elliptical cross-section by shaping bores along the longitudinal axis of the flat glass fibres and working- in the plastic film coating by heat-calendering thereto.
- the plastic film covering the surface of glass fibres is fixed by a so-called rivet binding on the surface of the glass tape and as a consequence, the strength of the plastic laminate is identical to that of the plastic carrier even under the effect of a tor ⁇ ional stress.
- An additional basis of the invention is the recognition that the primary glass fibres of elongated elliptical cross-section are connected with the plstic carrier layer not only through an adhesion binding but also by a mechanical connection whereby the torsional strength of the tape is also increased.
- the invention is based on the recognition that the utilization of primary glass fibres of elongated elliptical cross-section renders possible to simplify also the techniques of preparing the basic laminate since the flat fibres can be introduced together with the plastic material without any ready-sorting into the crosshead used for developing the basic laminate.
- the invention relates to an information-carrying magnetic tape with improved properties, which contains a magnetizable electric information-carrying layer applied onto the one side of a plastic carrier layer in a manner known per ⁇ e , wherein parallel with the longitudinal axis od the magnetic tape primary glass fibres provided with a plastic coating compatible with the material of the plastic carrier layer are arranged in the plastic carrier layer. It is characteristic of the magnetic tape of the invention that the primary glass fibres situated in the plastic carrier layer have an elongated elliptical cross-section.
- a preferred embodiment of the information-carrying magnetic tape according to the invention contains glass fibres, in the elliptical cross-section of which the average ratio of the principal axis (a) to the minor axis (b) of the ellipse falls between 10:1 and 100:1, preferably between 20:1 and 90:1, more preferably between 60:1 and 80:1.
- bores are formed on the surface of the flat glass fibres covered by the plastic film, suitably by using impulse laser techniques.
- the diameter of the bores preferebly agrees with the thickness of the glass fibres, i.e. it is approximately 5-12 micrometer ( ⁇ m) .
- a demag ⁇ netization-inhibiting metal layer of 0.4-8 ⁇ m, preferably 0.5-5 ⁇ m, in thickness is arranged on the side of the plastic carrier layer opposed to its side coated with the information-carrying layer. This metal layer may preferably be applied by vapourization of aluminium, copper or silver under reduced pressure.
- the metal layer protects against demagnetization whereas the primary glass fibres of elongated elliptical cross-section inhibit above all the elongation of the magnetic tape. Thereby magnetic tapes can be produced with a much better quality than that of the tapes known in the prior art.
- an additional insulating layer is applied to the metal layer from outside, which is preferably made of plastic material, suitably by whirling-bed sintering.
- the material of the insulating layer is conveniently identical to that of the carrier layer although it may be different therefrom; it is essential that it be compatible with the metal layer. It is convenient to select the plastics used in such a way that they be compatible with each other and the glass.
- the material of the plastic carrier layer is preferably polyamide, polyvinyl acetate or polyethylene therephthalate, its thickness is 10-16 ⁇ m, preferably " 12-14 ⁇ m.
- the glass fibres are fitted also with a coating compatible with the material of the plastic carrier layer. It is suitable to coat the glass fibres with an aqueous solution of an organic silicon compound and polyvinyl acetate; or with an aqueous solution of chromium methyl methacrylate; or with an aqueous solution of an aliphatic amine containing an epoxy-compatible double bond and of polyvinyl acetate.
- An embodiment of the information-carrying magnetic tape of the invention is illustrated as an example in connection with the enclosed Figure 1.
- the glass fibres 4 of elongated elliptical cross-section are arranged, which are fitted also with a coating 5, which is compatible with the material of the plastic carrier layer, in order to assure the appropriate stability.
- the glass fibres 4 have suitably an elliptical cross- section, the principal axis (a) of which is 150-360 micrometer and its minor axis (b) is 5-12 micrometer; this means that the ratio of the principal axis to the minor axis of the ellipse is suitably selected between 30 and 70.
- a metal layer 3 is applied, conveniently by va- pourization under reduced pressure, onto the side of the plastic carrier layer 1 opposed to its side fitted with the information-carrying layer 2.
- the material of this metal layer is preferably aluminium, copper or silver.
- An additional insulating layer 6 is also formed on the metal layer 3 from outside, the material of which is suitably identical to that of the plastic carrier layer 2 althoug it may be also different therefrom. However, it is an essential requirement that the material of the insulating -6-
- the primary glass fibres 4 of elongated elliptical cross-section of the magnetic tape according to the invention with bores possessing a diameter essentially agreeging with the thickness of the glass fibres, i.e. with the minor axis of the ellipse, suitably 10-12 micrometer, in order to fasten the plastic film covering the surface of the glass tape by so-called rivet binding, during the heat-calendering step of the production technology and in this way to assure for the torsional stress of the laminate the same strength as that of the plastic carrier used.
- the main advantages of the information-carrying magnetic tape of the invention possessing improved properties may be summarized as follows. a) By utilizing primary glass fibres of elongated elliptical cross-section, the specifically utilizable amount of glass fibres in the basal laminate can significantly be increased and thus the tensile strength of the tape can be increased to a similar extent. b) The primary glass fibres of elongated elliptical cross-section are connected with the plastic carrier layer not only by an adhesion binding but also by a mechanical connection, whereby the torsional strength of the tape is also increased.
- the primary glass fibres of elongated elliptical cross-section are not splitted out from the plastic coating under effect of the force appearing on bending, even in the case of a small bending radius.
- the glass fibres of elongated elliptical cross- section can be prepared even from highly impure, cheap glass basic material without a perceptible decrease in the tensile strength of the primary fibres; this results in an important diminution of the production costs.
- e) By utilizing the glass fibres of elongated elliptical cross-section, it becomes possible to simplify the production technology of the basic laminate since the flat fibres together with the plastic can be introduced without any free-sorting into the press head/crosshead used for developing the basic laminate.
Landscapes
- Laminated Bodies (AREA)
Abstract
The invention relates to an information-carrying magnetic tape with improved properties, which contains a magnetizable electric information-carrying layer (2) applied onto one side of a plastic carrier layer (1) in a manner known per se, wherein parallel with the longitudinal axis of the magnetic tape glass fibres (4) provided with a plastic coating (5) compatible with the material of the plastic carrier layer (4) are arranged in the plastic carrier layer (1). It is characteristic of the magnetic tape according to the invention that primary glass fibres (4) of elongated elliptical cross section are arranged in the plastic carrier layer (1). In the information-carrying magnetic tape according to the invention, the specifically utilizable amount of the glass fibres can considerably be increased; therefore, the tensile strength of the tape can be increased to a similar extent.
Description
MAGNETIC TAPE
The invention relates to an information-carrying magnetic tape with improved properties, which contains a magnetizable electric information-carrying layer applied onto the one side of a plastic carrier layer in a manner known per εe , wherein parallel with the longitudinal axis of the magnetic tape glass fibres provided with a plastic coating compatible with the material of the plastic carrier layer are arranged in the plastic carrier layer.
It is known that magnetic tapes of various kinds, including also the plastic-base information-carrying tapes used in magnetophones (tape-recorders) , computer-recorders, video cassette recorders and similar equipments, are developed in such a manner that they contain a plastic carrying layer designed and sized for substantially mechanical stress, and the electric signal- and information-recording layer consisting of metal oxide, mostly gamma-ferric oxide and chromic oxide, is applied thereto.
In the Hungarian patent specification No. 205,478 an information-carrying magnetic tape is disclosed, which contains a magnetizable electric information-carrying layer applied onto the one side of a plastic carrier layer wherein, in the plastic carrier layer, glass fibres provided with a plastic coating compatible with the material of the plastic carrier layer are arranged parallel with each other and the longitudinal axis of the magnetic tape. This magnetic tape eliminated the drawback of earlier known information-carrying magnetic tapes that, after a certain time, they suffered permanent deformation under effect of mechanical stress caused by high-speed winding and back-winding and above all, by a longitudinal elongation. During the further use this elongation induced a distortion both in the tracing as well as reproduction of signals.
The magnetic tape according to the Hungarian patent specification referred to above eliminated also an other drawback of earlier known magnetic tapes, namely that their plastic carrier layer did not assure any protection to the
metal oxide particles reverse-magnetized to varying extent against reverse magnetization of outer origin or between the particles themselves.
However, a disadvantage of the magnetic tape according to the Hungarian patent specification referred to above is that the amount of circular-section glass fibres, which can specifically be utilized in the basal laminate, is low whereby the tensile strength of the tape is restricted. An other drawback of this tape is that, as a consequence of the low tensile stength of circular-section glass fibres, a continuous bulk production can be realized only difficultly and expensively. An additional disadvantage of this magnetic tape is that high-purity glass fibres being free from impurities, i.e. those produced from very expensive glass basic material, can only be used for its manufacture.
The aim of the present invention is to eliminate the drawbacks of the known solutions and thereby to develop an information-carrier magnetic tape possessing more favourable tensile strength and rendering possible the utilization also of glass fibres prepared from highly contaminated cheap glass material.
The invention is based on the recognition that the above aim can fully be achieved by arranging primary glass fibres of elongated elliptical ("flat") cross-section in the plastic carrier layer.
The invention is furthermore based on the recognition that the flexibility of the tape is also increased in the case of glass fibres with elongated ellipse-form. This means that under the effect of a mechanical force occurring on bending, the glass fibre is not splitted out from the plastic coating material even in the case of a small bending radius ("strap effect") , which has a practical importance above all because of the permanent bending stress appearing on winding. A further basis of the invention is the recognition that the glass fibres of elongated elliptical cross-section may be prepared even from considerably contaminated cheap basic glass material without a perceptible decrease in the
tensile strength of the primary glass fibres.
An other basis of the invention is the recognition that the plastic film covering the surface of the glass fibres can be fixed to the surface of primary glass fibres of elongated elliptical cross-section by shaping bores along the longitudinal axis of the flat glass fibres and working- in the plastic film coating by heat-calendering thereto. Thus, the plastic film covering the surface of glass fibres is fixed by a so-called rivet binding on the surface of the glass tape and as a consequence, the strength of the plastic laminate is identical to that of the plastic carrier even under the effect of a torεional stress.
An additional basis of the invention is the recognition that the primary glass fibres of elongated elliptical cross-section are connected with the plstic carrier layer not only through an adhesion binding but also by a mechanical connection whereby the torsional strength of the tape is also increased.
Finally, the invention is based on the recognition that the utilization of primary glass fibres of elongated elliptical cross-section renders possible to simplify also the techniques of preparing the basic laminate since the flat fibres can be introduced together with the plastic material without any ready-sorting into the crosshead used for developing the basic laminate.
The above recognitions are surprising for a person skilled in the art, too, since even in the knowledge of the prior art it could not be expected that the tensile and •torsional strengths and flexibility of the tape would be increased by utilizing glass fibres of elongated elliptical cross-section instead of glass fibres of circular cross- section.
Based on those said above, the invention relates to an information-carrying magnetic tape with improved properties, which contains a magnetizable electric information-carrying layer applied onto the one side of a plastic carrier layer in a manner known per εe , wherein parallel with the longitudinal axis od the magnetic tape
primary glass fibres provided with a plastic coating compatible with the material of the plastic carrier layer are arranged in the plastic carrier layer. It is characteristic of the magnetic tape of the invention that the primary glass fibres situated in the plastic carrier layer have an elongated elliptical cross-section.
A preferred embodiment of the information-carrying magnetic tape according to the invention contains glass fibres, in the elliptical cross-section of which the average ratio of the principal axis (a) to the minor axis (b) of the ellipse falls between 10:1 and 100:1, preferably between 20:1 and 90:1, more preferably between 60:1 and 80:1.
According to an other preferred embodiment bores are formed on the surface of the flat glass fibres covered by the plastic film, suitably by using impulse laser techniques. The diameter of the bores preferebly agrees with the thickness of the glass fibres, i.e. it is approximately 5-12 micrometer (μm) . According to a further preferred embodiment a demag¬ netization-inhibiting metal layer of 0.4-8 μm, preferably 0.5-5 μm, in thickness is arranged on the side of the plastic carrier layer opposed to its side coated with the information-carrying layer. This metal layer may preferably be applied by vapourization of aluminium, copper or silver under reduced pressure. The metal layer protects against demagnetization whereas the primary glass fibres of elongated elliptical cross-section inhibit above all the elongation of the magnetic tape. Thereby magnetic tapes can be produced with a much better quality than that of the tapes known in the prior art.
According to a further preferred embodiment an additional insulating layer is applied to the metal layer from outside, which is preferably made of plastic material, suitably by whirling-bed sintering. The material of the insulating layer is conveniently identical to that of the carrier layer although it may be different therefrom; it is essential that it be compatible with the metal layer.
It is convenient to select the plastics used in such a way that they be compatible with each other and the glass. The material of the plastic carrier layer is preferably polyamide, polyvinyl acetate or polyethylene therephthalate, its thickness is 10-16 μm, preferably"12-14 μm.
In order to provide the suitable stability, the glass fibres are fitted also with a coating compatible with the material of the plastic carrier layer. It is suitable to coat the glass fibres with an aqueous solution of an organic silicon compound and polyvinyl acetate; or with an aqueous solution of chromium methyl methacrylate; or with an aqueous solution of an aliphatic amine containing an epoxy-compatible double bond and of polyvinyl acetate. An embodiment of the information-carrying magnetic tape of the invention is illustrated as an example in connection with the enclosed Figure 1.
In the plastic carrier layer 1, parallel to the longitudinal axis of the magnetic tape, the glass fibres 4 of elongated elliptical cross-section are arranged, which are fitted also with a coating 5, which is compatible with the material of the plastic carrier layer, in order to assure the appropriate stability.
The glass fibres 4 have suitably an elliptical cross- section, the principal axis (a) of which is 150-360 micrometer and its minor axis (b) is 5-12 micrometer; this means that the ratio of the principal axis to the minor axis of the ellipse is suitably selected between 30 and 70.
A metal layer 3 is applied, conveniently by va- pourization under reduced pressure, onto the side of the plastic carrier layer 1 opposed to its side fitted with the information-carrying layer 2. The material of this metal layer is preferably aluminium, copper or silver. An additional insulating layer 6 is also formed on the metal layer 3 from outside, the material of which is suitably identical to that of the plastic carrier layer 2 althoug it may be also different therefrom. However, it is an essential requirement that the material of the insulating
-6-
layer 6 be compatible with the material of metal layer 3.
It is preferable to provide the primary glass fibres 4 of elongated elliptical cross-section of the magnetic tape according to the invention with bores possessing a diameter essentially agreeging with the thickness of the glass fibres, i.e. with the minor axis of the ellipse, suitably 10-12 micrometer, in order to fasten the plastic film covering the surface of the glass tape by so-called rivet binding, during the heat-calendering step of the production technology and in this way to assure for the torsional stress of the laminate the same strength as that of the plastic carrier used.
The main advantages of the information-carrying magnetic tape of the invention possessing improved properties may be summarized as follows. a) By utilizing primary glass fibres of elongated elliptical cross-section, the specifically utilizable amount of glass fibres in the basal laminate can significantly be increased and thus the tensile strength of the tape can be increased to a similar extent. b) The primary glass fibres of elongated elliptical cross-section are connected with the plastic carrier layer not only by an adhesion binding but also by a mechanical connection, whereby the torsional strength of the tape is also increased. c) Owing to the strap effect, the primary glass fibres of elongated elliptical cross-section are not splitted out from the plastic coating under effect of the force appearing on bending, even in the case of a small bending radius. d) The glass fibres of elongated elliptical cross- section can be prepared even from highly impure, cheap glass basic material without a perceptible decrease in the tensile strength of the primary fibres; this results in an important diminution of the production costs. e) By utilizing the glass fibres of elongated elliptical cross-section, it becomes possible to simplify the production technology of the basic laminate since the
flat fibres together with the plastic can be introduced without any free-sorting into the press head/crosshead used for developing the basic laminate.
Claims
1. An information-carrying magnetic tape with improved properties, which contains a magnetizable electric information-carrying layer (2) applied onto the one side of a plastic carrier layer (1) in a manner known per εe wherein parallel with the longitudinal axis of the magnetic tape glass fibres (4) provided with a plastic coating (5) compatible with the material of the plastic carrier layer (1) are arranged in the plastic carrier layer (1) , characterized in that primary glass fibres (4) of elongated elliptical cross-section are arranged in the plastic carrier layer (1) .
2. A magnetic tape as claimed in claim 1, characterized in that the average ratio of the principal axis (a) to the minor axis (b) of the ellipse falls between 10:1 and 100:1, preferably between 20:1 and 90:1, more preferably between 60:1 and 80:1 in the elliptical cross-section of the glass fibres (4) .
3. A magnetic tape as claimed in claim 1, characterized in that the principal axis of the primary glass fibres (4) of elongated elliptical cross-section is of 150-360 micrometer in size whereas the minor axis is of 5-12 micrometer in size.
4. A magnetic tape as claimed in claim 1, characterized in that the primary glass fibres (4) contain along their longitudinal axis bores with a diameter essentially agreeing with their own thickness.
5. A magnetic tape as claimed in claim 1, characterized in that a demagnetization-inhibiting metal layer (3) is arranged on the side of the plastic carrier layer (1) opposed to the informa ion-carrying layer (2) .
6. A magnetic tape as claimed in claim 5, characterized in that the material of metal layer (3) is aluminium, copper or silver.
7. A magnetic tape as claimed in claim 5, characterized in that an additional insulating layer (6) formed from a plastic is arranged on the outer side of the metal layer (3).
8. A magnetic tape as claimed in claim 1, characterized in that the plastics used are compatible with each other and the glass.
9. A magnetic tape as claimed in claim 1, characterized in that the plstic carrier layer (1) is polyamide, polyvinyl acetate or polyethylene terephthalate.
10. A magnetic tape as claimed in claim 1, characterized in that the coating (5) of the glass fibres (4) is an aqueous solution of an organic silicon compound and polyvinyl acetate or an aqueous solution of chromium methyl methacrylate and polyvinyl acetate or an aqueous solution of an aliphatic amine containing an epoxy-compatible double-bond aliphatic amine and polyvinyl acetate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU27502/95A AU2750295A (en) | 1994-07-11 | 1995-06-22 | Magnetic tape |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| HU9402070A HU213130B (en) | 1994-07-11 | 1994-07-11 | Improved information carrying magnetic tape |
| HUP9402070 | 1994-07-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1996002053A1 true WO1996002053A1 (en) | 1996-01-25 |
Family
ID=10985423
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/HU1995/000027 Ceased WO1996002053A1 (en) | 1994-07-11 | 1995-06-22 | Magnetic tape |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2750295A (en) |
| HU (1) | HU213130B (en) |
| WO (1) | WO1996002053A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6019813A (en) * | 1995-05-26 | 2000-02-01 | H.C. Starck Gmbh & Co. Kg | Cobalt metal agglomerates, process for producing the same and their use |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1694010A1 (en) * | 1968-02-10 | 1971-06-09 | Walter Dr Phil Dannoehl | Fiber-reinforced plastic |
| GB1271163A (en) * | 1969-09-15 | 1972-04-19 | Ncr Co | Magnetic record medium |
| DE2461201A1 (en) * | 1973-12-27 | 1975-07-10 | Fuji Photo Film Co Ltd | Magnetic recording material prodn. - with annealing in static magnetic field to improve sensitivity |
-
1994
- 1994-07-11 HU HU9402070A patent/HU213130B/en not_active IP Right Cessation
-
1995
- 1995-06-22 WO PCT/HU1995/000027 patent/WO1996002053A1/en not_active Ceased
- 1995-06-22 AU AU27502/95A patent/AU2750295A/en not_active Abandoned
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1694010A1 (en) * | 1968-02-10 | 1971-06-09 | Walter Dr Phil Dannoehl | Fiber-reinforced plastic |
| GB1271163A (en) * | 1969-09-15 | 1972-04-19 | Ncr Co | Magnetic record medium |
| DE2461201A1 (en) * | 1973-12-27 | 1975-07-10 | Fuji Photo Film Co Ltd | Magnetic recording material prodn. - with annealing in static magnetic field to improve sensitivity |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6019813A (en) * | 1995-05-26 | 2000-02-01 | H.C. Starck Gmbh & Co. Kg | Cobalt metal agglomerates, process for producing the same and their use |
Also Published As
| Publication number | Publication date |
|---|---|
| HU9402070D0 (en) | 1994-09-28 |
| HUT73621A (en) | 1996-08-28 |
| AU2750295A (en) | 1996-02-09 |
| HU213130B (en) | 1997-02-28 |
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