CN1179851A - Magnetic recording media - Google Patents

Abstract

A tape-type magnetic recording media (I) including a non-magnetic substrate (III), at least one film applied to the substrate and, in at least one of these films, an inorganic acicular pigment (II) suitable for use as a supporting pigment, the ratio of the mean length to the mean diameter of the pigment (II) being 3:1~15:1 and the mean modulus of elasticity of the films being not less than 15 GPa in the longitudinal direction of the tape-type recording medium (I).

Description

Magnetic recording media

The present invention relates to magnetic recording media with a kind of supporting pigment (supporting pigment) stabilization.

For modern magnetic recording media, the frequent speed that needs bigger storage volume and obtain store information faster.To tape shape recording medium, these requirements mean that at first requirement, tape thickness constantly reduces on the one hand, and on the other hand, magnetic coating thickness constantly reduces, and are like this for using maximum longitudinal recording methods in the reality at least.At second requirement, the result is that tape speed constantly increases.For example, the tape thickness of present high storage capacity tape shape recording medium is 10 μ m only, the about 1 μ m of the magnetic coating thickness relevant with read-write operation, and the tape speed in the Modern High-Speed driver may be in the scope of several meters of per seconds.

Especially for opening-stop operation, when purpose is when obtaining the packets of information that chooses in advance, high acceleration may longitudinally produce acting force to magnetic recording media in some cases.Continuous therewith is the dynamic tensile load and acts on the short-term on the tape xsect, high dynamic tensile stress value.This may even be enough to make tape shape recording medium to produce plastic yield, and this plastic yield may cause tearing being attended by under the continuous stress that load repeats to change.

Usually adopt the tape base material of mylar, the person that for example contains the polyethylene terephthalate as tape shape recording medium.Know that the elastic modulus of this material is 4～8GPa, look the actual conditions of production run and different, and limit of elasticity is no more than about 0.5% length growth rate.These numerical value are tested in static tensile test film sample and are obtained, and these samples cut out along the machine direction of film production machine, and vise with a suitable tensile test device.Therefore, tape base material itself can absorb the long-pending maximum tension stress that is no more than these two features, i.e. 40MPa in elastic range.

In EP-A 0 520 155, be thinner than or the elastic range feature that equals the modern magnetosphere of 1 μ m thickness is minimum yield point 30MPa, the minimum elongation rate 0.2% during surrender.The above-mentioned limit of elasticity of this tape base layer and this magnetosphere determined, the elastic stretching stress of the tape shape recording medium that is constituted with described tape base layer and described magnetosphere is 30～40MPa, and elastic extension is 0.2～0.5%.

Similarly, the theme of JP-A 57-078 630, JP-A 57-078 629 and JP-A 02-260 229 also is the elasticity of tape shape recording medium.The innovation concept of preceding two documents is that the ratio of the elastic modulus of definite vertical and horizontal is not more than 2.5, so that magnetic recording property can not be subjected to the infringement of the distortion of recording medium.JP-A 02-260 229 relates to life-span and the behavior in service thereof of improving magnetosphere.This article suggestion increases another magnetosphere as solution, and this magnetosphere is as the lower floor between non magnetic tape base layer and physical record layer, and the elastic modulus of this lower floor is greater than recording layer.

The tape shape magnetic recording media of producing according to these patents all can not have gratifying high resiliency drawing stress scope and gratifying high elastic modulus.

An object of the present invention is to correct above-mentioned shortcoming, and a kind of flexible tape shape magnetic recording media is provided, be used for the time dependent high drawing stress situation of high speed tape drive.

We have found that a kind of like this tape shape recording medium I can reach this purpose, this tape shape recording medium comprises a non magnetic tape base layer III, on this tape base layer, apply one deck at least, and in one deck at least of these layers, contain a kind of being applicable to and be at least 3 inorganic acicular pigment II as supporting pigment and its average length and average diameter ratio, wherein, above-mentioned each layer is not less than 15GPa along the average elasticity modulus of tape shape recording medium I on vertically.

We have also found suitable do supporting pigment novelly contains the inorganic acicular pigment VI of chromium and VII, its preparation method and application thereof, strengthens in particular for the anisotropy of polymeric material.

In this article, the elastic modulus E when elastic modulus is understood that to stretch, it is compared and gets with longitudinal tensile strain by tension, and can determine according to well-known method easily.

Supporting pigment should adopt ferromagnetism and the inorganic acicular pigment II of nonferromagnetic.

Ferromagnetic pigments II should use metallic pigments, for example alloy of Fe, Co, Ni and these elements, and oxide pigment, for example γ-Fe ₂O ₃And contain γ-Fe of Co ₂O ₃, Fe ₃O ₄, preferably contain the oxide pigment of chromium, for example CrO ₂, especially those molecular formula are the oxide pigment of VI:

Cr ^aO _x·nH ₂O????????????????????????VI

Wherein, a is the average valence of chromium, 3.0＜a≤3.25, preferred 3.0＜a≤3.1; Is x the oxygen equivalent that quantivalency determined of chromium? N then is a water cut, 0＜n＜(4-a)/2.

According to the present invention, pigment VI can be made up of kernel that accounts for weight 50% and the shell that accounts for weight 50%, and the atomic ratio of Cr in kernel and the shell (IV) and Cr (III) may be identical or different.

Nonferromagnetic pigment II suitable preferred oxides pigment, for example FeOOH, α-Fe ₂O ₃, especially molecular formula is the chromium pigment that contains of VII:

Cr ₂O ₃·nH ₂O?????????????????????????VII

Wherein, the n value is 0～0.5.

The preparation of pigment VI and VII is by under 400～500 ℃, under preferred 440～480 ℃, especially advantageously under 450～470 ℃, in the gas that especially contains molecular oxygen, and for example in the air, the following pigment VIII of heating molecular formula:

CrO _x

Wherein, x is 1.8≤x≤2.2.The reaction time that generates these two kinds of pigment is 0.5～10 hour, and preferred 0.5～2 hour, wherein pigment VIII can adopt original known mode to purify for example water flushing before heating.

Advantageously, pigment VIII can handle with organic compound or preferred mineral compound before heating, inorganic base for example, should use alkali metal hydroxide, alkaline earth metal hydroxide and earth metal oxyhydroxide, for example potassium hydroxide, calcium hydroxide, especially NaOH, perhaps their basic salt, for example carbonate or sulphite, especially sodium sulphite.Should in the aqueous solution, be 7～14 especially at inorganics at pH, especially 11～13 times, 10～90 ℃ of reactions 0.5～10 hour down, especially 0.5～5 hour, but except the sulphite, 7～9 pH value is adopted in its suggestion.

Pigment VI and VII also can at first react under hydrothermal condition by pigment VIII and a kind of reductive agent and prepare, and temperature of reaction is 110～250 ℃, and preferred 160～230 ℃, especially 190～210 ℃; Reaction pressure is 2～500 crust, preferred 100～300 crust, especially 150～250 crust; Course of reaction is 10～500 hours, preferred 50～250 hours, and especially 80～120 hours.Reductive agent should be used mineral compound, perhaps preferably has organic compounds, for example carboxylic acid, especially oxalic acid.

Reaction product can further be handled in reaction mixture, perhaps should use known method, for example filters, and separates from suspending liquid, and should purify, for example flushing.

According to the present invention, then under 100～500 ℃, under preferred 200～400 ℃, in a kind of gas of especially molecule-containing keto, air for example, the heating reaction product, the reaction time is 0.5～10 hour, preferred 0.5～2 hour.

Reaction product can be handled with organic compound or preferred mineral compound before heating, inorganic base for example, should use alkali metal hydroxide, alkaline earth metal hydroxide and earth metal oxyhydroxide, for example potassium hydroxide, calcium hydroxide, especially NaOH, perhaps their basic salt, for example carbonate or sulphite, especially sodium sulphite.Should in the aqueous solution, be 7～14 especially at inorganics at pH, especially 11～13 times, 10～90 ℃ of reactions 0.5～10 hour down, especially 0.5～5 hour, but except the sulphite, 7～9 pH value is adopted in its suggestion.

Pigment VI and VII can handle with organic compound or preferred mineral compound, inorganic base for example, should use alkali metal hydroxide, alkaline earth metal hydroxide and earth metal oxyhydroxide, for example potassium hydroxide, calcium hydroxide, especially NaOH, perhaps their basic salt, for example carbonate or sulphite, especially sodium sulphite.Should in the aqueous solution, be 7～14 especially at inorganics at pH, especially 11～13 times, 10～90 ℃ of reactions 0.5～10 hour down, especially 0.5～5 hour, but except the sulphite, 7～9 pH value is adopted in its suggestion.

As well-known, supporting pigment II, VI and VII can contain other chemical element or compound.According to the present invention, the spicule average length of acicular pigment II, VI and VII is 3: 1～15: 1 with the ratio of spicule mean diameter, and preferred 5: 1～10: 1, length was 50～400nm, preferred 90～300nm, especially 100～200nm.According to DIN 66132 tests, the specific surface area of pigment VI and VII should be 30～150m ²/ g, preferred 50～100m ²/ g.According to the present invention, the saturation magnetization of pigment VI is 0.1～65nTm ³/ g, preferred 0.1～40nTm ³/ g, especially 0.1～22nTm ³/ g, and residual magnetic induction is 0.05～24nTm ³/ g, preferred 0.05～12nTm ³/ g, especially 0.05～5nTm ³/ g.

Pigment II preferentially is VI and VII, is suitable for the especially anisotropy reinforcement of polymeric material.This polymeric material may be suitable for coated surfaces, and for example film perhaps applies three-dimensional body, such as right cylinder, and wire rod for example.

In order to produce polymeric material or the layer of strengthening in this mode, according to the present invention, in the fused mass or solution of polymeric material, perhaps in the fused mass or solution of the compound that can be used for preparing polymeric material, add pigment II, especially VI or VII, curing mixture or let alone to solidify then.

Anisotropy for polymeric material is strengthened, and is particularly conducive to be used among the novel magnetic recording media I, can be before the curing or curing of polymeric material, and directed supporting pigment II, especially VI or VII.

For nonferromagnetic supporting pigment,, for example potpourri is toppled over, is flow through a narrow slit by measure reaches this orientation such as rheology.For ferromagnetism supporting pigment II, especially VI, should carry out orientation by means of an externally-applied magnetic field.

Be clipped in the particularly advantageous magnetic recording media that tape base layer III and is suitable for being formed between the layer IV of information storage by the layer of an iron content magnetic bearing pigment II, the orientation ratio among the layer V should be 2.5 at least, and layer IV be at least 4.0.Orientation ratio refer to tape shape magnetic recording media at the residual magnetic induction on the rotation direction and magnetic recording media at ratio perpendicular to the residual magnetic induction on this direction.The orientation of pigment II (preferred VI and VII) can be measured with ultrathin sectioning.For this reason, use a transmission electron microscope being not less than under 20,000 times the enlargement factor, observing thickness is the ultra-thin section of 0.1～0.2 μ m.In the wide measured zone of about 20 μ m, 50～100 acicular pigments are selected in every section at random, determine along tape mean diameter (d longitudinally _L) and horizontal mean diameter (d _T).

Work as d _L〉=2d _TThe time, think that pigment is mainly along the tape portrait orientation.

Know, tape shape magnetic recording media I contain non magnetic tape base layer III and at least one deck be suitable for storing the layer IV (magnetosphere) of magnetic information.

This novel magnetic recording media I can be in non magnetic tape base layer III, is suitable among the layer IV of information storage at one deck at least, or at least one V layer by layer, contains described supporting pigment II.Layer V can place between tape base layer III and the magnetosphere IV, perhaps places the deviating from the magnetosphere IV one side of tape base layer III.

Non magnetic tape base layer III can adopt conventional rigidity or flexible tape base layer, especially linear polyesters, the film of polyethylene terephthalate for example, and its thickness is generally 4～200 μ m, especially is 6～36 μ m.

The magnetosphere IV of this novel magnetic recording media I can based on or evaporation or sprayed metal film, this film mainly contains ferromagnetic element, for example Fe, Co and Ni or their alloy are perhaps based on ferromagnetic pigments.

In order to produce this layer, can employing itself known mode is pigment, if desired and fillers dispersed in the solution that contains a kind of solvent, bonding agent and other adjuvant (as lubricant and spreading agent), and can be coated on the non magnetic tape base layer.When ferromagnetic pigments after the orientation, can adopt common mode further to handle in a high-intensity magnetic field, for example remove when needed desolvate, cure adhesive and use the calender press polish subsequently.

Magnetic paint is preferably conventional oxide pigment, for example γ-Fe ₂O ₃, Fe ₃O ₄And CrO ₂, or metallic pigments, as Fe, Co and Ni.Well-known is that these pigment can contain other chemical element or compound.

Used solvent can be water, ether (for example tetrahydrofuran or dioxane), ketone (for example butanone or cyclohexanone), ester (for example ethyl acetate) or hydrocarbon (for example alkane or aromatic hydrocarbons) as a rule, or the potpourri of these solvents.

Know, bonding agent should be used polyacrylate, polymethacrylate, polyacrylamide, polyvinyl, as polystyrene, Polyvinylchloride, polyvinyl acetate (PVA), polyvinyl proprionate or polyacrylonitrile, the bonding agent of fibre-bearing element, as cellulose esters, especially cellulose nitrate, cellulose acetate, Triafol T, acetyl-cellulose propionate or acetyl-cellulose butyrate, phenoxy resin, epoxy resin, or the multipolymer of optimization polyurethane and block polymer or these compounds.Suitable polyurethane can referring to, for example DE-B 11 06 959, DE-B 27 53 694, DE-A 32 26 995, DE-A 32 27 163 and DE-A 32 27 164 are described.Can adopt polyurethane as unique bonding agent, perhaps preferably, use, for example polyvinyl formal, phenoxy resin, PVC or PVC multipolymer with other polymkeric substance.

The wearing quality of polyurethane or polyurethane mixture and elastic modulus can be further by with these compounds and the polyfunctional isocyanate is crosslinked improves, especially have two above isocyanate groups persons.Should adopt two functional isocyanate, as inferior cresyl vulcabond, hexamethylene diisocyanate or have molecular formula Isophorone diisocyanate, with the polyvalent alcohol addition reaction, perhaps form and prepare this crosslinking chemical by biuret or chlorinated isocyanurates.The adduct of trimethylolpropane and diglycol and inferior cresyl vulcabond especially is suitable for and makes crosslinking chemical.Through simple pilot study several times, just can determine the ratio of required crosslinking chemical quantity and the polyurethane quantity that reaches the optimum performance feature easily.

Lubricant commonly used is the carboxylic acid that contains 10～20 carbon atoms, especially stearic acid and palmitic acid, carboxylic acid derivates, and as their salt, ester and acid amides, or fluorinated hydrocarbons.

Spreading agent can use kation, non-ionic surfactant by common mode, the preferred anionic surfactant, and such as the phosphate of carboxylate, sulfonate, phosphonate or hydrocarbon, alkyl or aryl compound especially.

Know that filler should be used inorganic or organic pigment, as aluminium oxide, silicon dioxide, carbon black, tygon and polypropylene.

When producing magnetic recording media I, can on the tape base layer, apply a plurality of magnetosphere IV, wherein one deck contains a kind of supporting pigment II at least, perhaps a plurality of layers of V, wherein one deck contains a kind of supporting pigment II at least.

Embodiment

CrO ₂The preparation of pigment

Embodiment 1

In 10 minutes with 554g CrO ₃Be dispersed in the 159g water, under 40～60 ℃, in potpourri, slowly add 70g potassium antimonyl tartrate (PAT), and stirred 5 minutes down at 60 ℃.Under 20～30 ℃, add 170g Cr then while in 3 minutes, stir ₂O ₃

Fully stir 15 minutes then with homogenizing, simultaneous temperature rises to 80 ℃.

After potpourri is cooled to 30 ℃, in an autoclave, in 3 hours, be heated 320～350 ℃, and under this temperature, kept 9 hours, maximum pressure is 360 crust.Cooling mixture goes autoclave to press when mixture temperature is 200 ℃ then.

Then at 50 ℃ of following desciccates and levigate.

Performance sees Table 1.

Embodiment 2a-g

Stir down 25 ℃ of low suspensions of the product among the 1000g embodiment 1 are being dissolved in by 780g oxalic acid in the 1490g water in the resulting potpourri.Then potpourri is placed autoclave, under the pressure that 210 ℃ and potpourri self produce, kept 96 hours.

Again product is heated in air by the described treatment conditions of table 2.

Performance sees Table 2.

Embodiment 3

Be dispersed in the 1000g water product of 100g embodiment 1 gained and wet-milling.Then, filtering mixt, the water flush cake, is dispersed in residue in the 1000g water less than 50 μ s up to the conductivity of wash water under 20 ℃ again.

To be dissolved in the solution that obtains in the 50g water by the 11g sodium sulphite then and add in the potpourri, and stir 30 minutes down at 20～28 ℃.

Then filtration product, and flush cake, up to the conductivity of wash water under 20 ℃ less than 50 μ s.

Filter cake 50 ℃ down dry, and levigate to particle size less than 1mm.

Performance sees Table 1.

Embodiment 4

Be dispersed in the 1000g water product of 100g embodiment 1 gained and wet-milling.Then, filtering mixt, the water flush cake, is dispersed in residue in the 1000g water less than 50 μ s up to the conductivity of wash water under 20 ℃ again.Then the pH value is transferred to 12, and under 55 ℃ and pH=12, stirred 2 hours with the sodium hydroxide solution of 15% weight concentration.

Then, filtration product, the water flush cake, up to the conductivity of wash water under 20 ℃ less than 50 μ s.Filter cake 50 ℃ down dry, and levigate to particle size less than 1mm.

Performance sees Table 1.

Embodiment 5

Be dispersed in the 1000g water product of 100g embodiment 1 gained and wet-milling.Then, filtering mixt, the water flush cake, is dispersed in residue in the 1000g water less than 50 μ s up to the conductivity of wash water under 20 ℃ again.

Stir and nitrogen protection under, with mixture heated to 85 ℃, add the 20g sodium sulphite down at 85 ℃ and be dissolved in the solution that obtains in the 100g water, and 85 ℃ of stirrings 2 hours down.

Then, filtration product, the water flush cake, up to the conductivity of wash water under 20 ℃ less than 50 μ s.

Filter cake 50 ℃ down dry, and levigate to particle size less than 1mm.

Performance sees Table 1.

Embodiment 6

Be dispersed in the 1000g water product of 100g embodiment 1 gained and wet-milling.Then, filtering mixt, the water flush cake, up to the conductivity of wash water under 20 ℃ less than 50 μ S, filter cake 50 ℃ down dry, and levigate to particle size less than 1mm.

Product heats in a rotary tube furnace, wherein stops 30 minutes down and in the air atmosphere at 460 ℃.

Performance sees Table 1.

Embodiment 7

Be dispersed in the 1000g water product of 100g embodiment 6 gained and wet-milling.Then, filtering mixt, the water flush cake, is dispersed in residue in the 1000g water less than 50 μ S up to the conductivity of wash water under 20 ℃ again.

With the sodium hydrate aqueous solution of 15% weight concentration the pH value is transferred to 12 then, and under 55 ℃ and pH=12, stirred 2 hours.

Afterwards, filtration product, the water flush cake, up to the conductivity of wash water under 20 ℃ less than 50 μ S.

Filter cake 50 ℃ down dry, and levigate to particle size less than 1mm.

Performance sees Table 1.

The preparation of magnetic recording media

Embodiment 8

First kind of thick dispersion of coating one deck 1.2 μ m on the thick non magnetic polyethylene terephthalate tape base layer of one deck 14 μ m, this dispersion contains 1000 weight portion embodiment, 5 described chromium oxide pigment, 75 weight portions contain the polyvinyl of polar bond group (anchor group), polyurethane, 25 weight portion stearic acid, 180 weight portion tetrahydrofurans and the 180 weight portion dioxs that 95 weight portions contain the polar bond group.Coating second kind of thick dispersion of one deck 0.4 μ m on this layer use the directional magnetic field orientation again, drying and with the calender press polish; It is that 133kA/m and specific surface area are 52m that second kind of dispersion contains 1000 weight portion coercive forces ²The ferromagnetic metal pigment of/g, 80 weight portion particle sizes are α-Al of 0.2 μ m ₂O ₃, 77 weight portions contain the polyvinyl of polar bond group, polyurethane, 10 weight portion phosphates, 25 weight portion stearic acid, 22.5 weight portion polyisocyanates, 1837.5 weight portion tetrahydrofurans and the 1837.5 weight portion dioxs that 77 weight portions contain the polar bond group.

Obtain a kind of novel magnetic recording media like this with good magnetic property and mechanical property.

Embodiment 9

Except first kind of dispersion is not to contain 1000 weight portion embodiment, 5 described chromium oxide pigment, but contain outside 1000 weight portion embodiment, the 7 described chromium oxide pigment, all the other processes are with embodiment 8.

Obtain so a kind of have excellent magnetism can with the novel magnetic recording media of mechanical property.

Embodiment 10

Except first kind of dispersion is not to contain 1000 weight portion chromium oxide pigment, be α-Fe of 25nm for 125nm, average pin diameter but contain the average pin length of 1000 weight portions ₂O ₃Outside the pigment, all the other processes are with embodiment 8.

Obtain a kind of novel magnetic recording media like this with good magnetic performance and mechanical property.

Comparative example

Except first kind of dispersion is not to contain 1000 weight portion chromium oxide pigment, be that 60nm, mean diameter are the TiO of 30nm but contain 1000 weight portion average lengths ₂Outside the pigment, all the other processes are with embodiment 8.

The elastic modulus of each layer of gained magnetic recording media is 13GPa.

Table 1

	Embodiment 1	Embodiment 3	Embodiment 4	Embodiment 5	Embodiment 6	Embodiment 7
							Length (nm)	????130	????130	????130	????130	????130	????130
Length/thickness	????7	????7	????7	????7	????7	????7
							Specific surface area (m 2/g)	????73	????73	????73	????73	????64	????64
Hc(kA/m)	????15	????15	????16	????15	????0	????0
							σ r(nTm 3/g)	????21	????16	????17	????13	????1	????1
σ m(nTm 3/g)	????77	????59	????64	????49	????6	????5

Table 2

Embodiment

Heating

Hc(kA/m)

????σ r??(nTm 3/g)

??σ m(nTm 3/g)

Specific surface area (m 2/g)

????2a	Not heating	????0	????0	????1	????76
						????2b	1h/250℃	????7	????1	????5	????74.6
????2c	1h/300℃	????17	????3	????14	????73.6
						????2d	1h/350℃	????19	????11	????39	????71.2
????2e	1h/400℃	????10	????7	????33	????71.5
						????2f	1h/450℃	????3.3	????2	????18	????68.8
????2g	1h/500℃	????6.2	????≤1	????7	????62.8

Claims (33)

1. tape shape magnetic recording media I, it contains a non magnetic tape base layer III, on this tape base layer, apply one deck at least, and in one deck at least of these layers, containing a kind of being applicable to as supporting pigment and its average length and average diameter ratio is 3: 1～15: 1 inorganic acicular pigment II, wherein, above-mentioned each layer is not less than 15GPa along the average elasticity modulus of tape shape recording medium I on vertically.

2. according to a kind of tape shape magnetic recording media I of claim 1, its elastic modulus on tape shape magnetic recording media I is vertical is not less than 20GPa.

3. according to a kind of recording medium I of claim 1 or 2, it contains

A) non magnetic tape base layer III and

B) one is suitable for the layer IV that magnetic information stores.

4. according to each a kind of recording medium I in the claim 1～3, comprise that one contains a kind of bonding agent and a kind of layer V that supports pigment.

5. according to each a kind of recording medium I in the claim 1～4, wherein non magnetic tape base layer III contains a kind of supporting pigment II.

6. according to each a kind of recording medium I in the claim 1～5, a layer IV who wherein is suitable for storing magnetic information contains a kind of supporting pigment II.

7. according to a kind of recording medium I of claim 3, its middle level V is arranged on a non magnetic tape base layer III and one and is suitable between the layer IV that magnetic information stores.

8. according to a kind of recording medium I of claim 3, wherein non magnetic tape base layer III is arranged on a layer V and one and is suitable between the layer IV that magnetic information stores.

9. according to each a kind of recording medium I in the claim 1～8, one of them layer IV that is suitable for storing magnetic information contains a kind of bonding agent and finely divided ferromagnetic pigments.

10. according to each a kind of recording medium I in the claim 1～8, one of them layer IV that is suitable for storing magnetic information consists essentially of a kind of ferromagnetic metal or ferromagnetic alloy.

11. according to each a kind of recording medium I in the claim 1～10, it contains a kind of ferromagnetic pigments as supporting pigment II.

12. according to a kind of recording medium I of claim 11, it contains ferromagnetic metal or alloy pigment as supporting pigment II.

13. according to a kind of recording medium I of claim 11, it contains the ferromagnetic metal oxide pigment as supporting pigment II.

14. according to a kind of recording medium I of claim 13, it contains γ-Fe ₂O ₃Pigment, contain γ-Fe of Co ₂O ₃Pigment, γ-Fe ₃O ₄Pigment or CrO ₂Pigment is as supporting pigment II.

15. according to a kind of recording medium I of claim 13, it contains the following needle-like of molecular formula and contains chromium pigment as supporting pigment:

Cr ^aO _x·nH ₂O?????????????VI

Wherein, a is the average valence of chromium, 3.0＜a≤3.25,

X is the oxygen equivalent that quantivalency determined of chromium,

N then is a water cut, 0＜n＜(4-a)/2,

Long and the average pin diameter ratio of the average pin of this pigment is 3: 1～10: 1.

16. according to a kind of recording medium I of claim 15, wherein pigment VI comprises

A) account for weight 50% kernel and

B) account for the shell of weight 50%

And Cr in kernel and the shell (IV) equates with the atomic ratio of Cr (III).

17. according to a kind of recording medium I of claim 15, wherein pigment VI comprises

A) account for weight 50% kernel and

B) account for the shell of weight 50%

And the Cr in the shell (IV) is higher than this value in the kernel with the atomic ratio of Cr (III).

18. according to a kind of recording medium I of claim 15, wherein pigment VI comprises

A) account for weight 50% kernel and

B) account for the shell of weight 50%

And the Cr in the kernel (IV) is higher than this value in the shell with the atomic ratio of Cr (III).

19. according to each a kind of recording medium I in the claim 1～10, it contains a kind of nonferromagnetic pigment as supporting pigment II.

20. according to a kind of recording medium I of claim 19, it contain FeOOH or-Fe ₂O ₃As supporting pigment II.

21. according to the recording medium I of claim 19, it contains formula VII pigment

Cr ₂O ₃·nH ₂O??????????????????????VII

As a kind of supporting pigment II, wherein, the n value is 0～0.5,

Long and the average pin diameter ratio of the average pin of this pigment is 3: 1～10: 1.

22. according to each a kind of recording medium I in claim 14～18 and 21, it contains

A) a kind of non magnetic tape base layer III, and be provided with on it

B) layer V who contains bonding agent and contain chromium needle-like metal oxide, the pigment average length of this metal oxide is at least 7 with the ratio of mean diameter, and orientation ratio is at least 4.And this layer V goes up and is provided with

C) layer IV who is suitable for information storage who contains a kind of bonding agent and ferromagnetic metal pigment, this tape shape recording medium I elastic modulus in the vertical is greater than 30GPa.

23. one kind is suitable for as supporting pigment and according to claim 15～18,21 and 22 pigment VI or VII.

24. according to being suitable for as the pigment VI or the VII that support pigment of claim 15～18 and 21～23, the average pin length of this pigment is 100～400nm.

25. preparation is according to the pigment VI of claim 15～18 and 21～24 or the method for VII, wherein heating molecular formula down at 400～500 ℃ is VIII

CrO _x??????????????????????????VIII

Pigment, at this

X satisfies 1.8≤x≤2.2.

26. preparation is according to the pigment VI of claim 15～18 and 21～24 or the method for VII, wherein molecular formula is VIII

CrO _x??????????????????????????VIII

Pigment 110～250 ℃ under hydrothermal condition with the reaction of a kind of reductive agent, 200～400 ℃ of heating down, at this, x satisfies 1.8≤x≤2.2 then.

27. according to the pigment VI of claim 15～18 and 21～26 or VII in the application that improves on the polymeric material mechanical property.

28. pigment VI and the application of VII on the anisotropy of polymeric material mechanical property is improved according to claim 15～18 and 21～26.

29. a kind of improvement method according to the mechanical property of the polymeric material of claim 27, wherein pigment VI or VII are added in the fused mass or solution of polymeric material, perhaps add in the fused mass or solution of the compound that can be used for preparing polymeric material, and then curing mixture or let alone to solidify.

30. anisotropy improvement method according to the polymeric material mechanical property of claim 28, wherein pigment VI or VII are added in the fused mass or solution of polymeric material, perhaps add in the fused mass or solution of the compound that can be used for preparing polymeric material, and wherein use directed these pigment of rheology method, and solidify these materials or let alone curing.

31. anisotropy improvement method according to the polymeric material mechanical property of claim 28, wherein pigment VI or VII are added in the fused mass or solution of polymeric material, perhaps add in the fused mass or solution of the compound that can be used for preparing polymeric material, and directed pigment in an externally-applied magnetic field wherein, and solidify these materials or let alone and solidify.

32. according to each getable potpourri in the claim 29～31.

33. contain a kind of a kind of magnetic recording media of the potpourri according to claim 32.