JPH0242627A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve surface smoothness, durability and traveling stability by incorporating a specific compd. into a magnetic layer and/or back coating layer. CONSTITUTION:This recording medium is constituted by incorporating the compd. expressed by formula I into the magnetic layer and/or back coating layer formed on a nonmagnetic base. In formula I, A denotes a trivalent combination group expressed by formula II, III, etc.; X1-X3 denote a divalent combination group expressed by formulas IV, V, etc.; Y1, Y2 denote a divalent combination group expressed by formulas VI, VIII, etc.; Rx denotes a hydroxyl group, alkenyl group, etc.; Rf denotes CmF2m+1, etc.; Rsi denotes a polysiloxane chain expressed by formula VIII. In formulas VI, VIII, l1 denotes >=1 integer; (m) in Rf denotes 3-20 integer; in formula VIII, R1 denotes a methyl group, etc.; R2, R3 denote a phenyl group, etc.; (n) denotes 1-520 integer. Since the lubricity and lubricity sustaining property are improved in this way, the traveling stability and durability are improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic recording medium, and more particularly, the lubricity and abrasion resistance of a magnetic layer and/or back coat layer are improved, and running stability and durability are improved. The present invention relates to a magnetic recording medium with excellent performance.

[Prior Art] Magnetic recording media such as magnetic tapes and magnetic disks run while contacting magnetic heads, guide members, etc., so the friction coefficient of the magnetic layer and/or back coat layer is small, resulting in poor running stability. In addition, the magnetic layer is required to have excellent durability, with little wear due to the strong contact with the magnetic head during recording and reproduction.

Therefore, as a measure to improve the lubricity and wear resistance of the magnetic layer and/or back coat layer, various additives have been conventionally incorporated into the magnetic layer and/or back coat layer. . Examples of this method include: (1) adding higher fatty acids, esters of higher fatty acids, metal soaps or amide, paraffin hydrocarbons to magnetic coatings consisting of magnetic powder and binder resin and/or back coat layers mainly consisting of binder resin; , a method of adding various types of lubricants such as silicone oil and fluorine oil to improve the lubricity of the magnetic layer surface and/or back coat surface; A method of improving sliding properties by adding solid lubricants such as molybdenum disulfide, graphite, wax, etc., and recently, solid lubricants such as graphite fluoride and fluororesin powder (JP-A-5
8-177525, JP-A-59-162644, etc.), (1) A perfluoroalkyl group-containing surfactant is contained in the magnetic layer and/or the back coat layer, and the surface of the magnetic layer and/or the back coat surface is Method for improving smoothness, durability, and dispersibility of magnetic powder (JP-A-59-1678
No. 37, No. 167838, No. 167839, No. 167840, No. 167841,
Publication No. 172140, etc.), (2) Containing fluorine-modified silicone oil with modified terminals and/or side chains in the magnetic layer and/or back coat layer to improve the smoothness and durability of the magnetic layer surface and/or back coat surface. Method for improving sex etc. (Unexamined Japanese Patent Publication No. 57-12
No. 417, No. 37730, No. 40752,
Publication No. 40753, Japanese Unexamined Patent Publication No. 58-91527,
There are proposals such as JP-A No. 59-94232, etc.).

[Problem to be Solved by the Invention 1] However, the various lubricants and fluorine-based surfactants that have been used in the past tend to fall off in the magnetic layer when the magnetic head is firmly attached to the magnetic layer, and they tend to fall off in the back coat layer. Since it is easy to fall off when it comes into contact with the guide pin of a tape cassette recording/reproducing device, the slipping effect disappears in a relatively short period of time, resulting in a problem that running stability and the like are impaired.

Furthermore, if large amounts of the various lubricants and fluorine-containing surfactants described above are used to improve the sustainability of the lubricity effect, the mechanical properties of the magnetic layer and/or back coat layer themselves may deteriorate, resulting in decreased durability. There were problems such as losses.

Furthermore, when a lubricant with poor compatibility with the binder resin, such as silicone oil, is added, excessive surface leakage (blooming) is likely to occur, resulting in tape sticking phenomena, stick/slip, etc. There was a problem that occurred.

As mentioned above, sufficient surface smoothness can be achieved with the minimum amount of addition.
At present, no lubricant or fluorine-based surfactant has been found that does not fall off even during one contact with a magnetic head and has excellent long-lasting lubricity.

[Means for Solving the Problems] As a result of intensive research to solve the above problems, the present inventors have developed a specific compound containing a perfluoroalkyl group and a polysiloxane chain in the molecule. By forming the containing magnetic layer and/or back coat layer on a non-magnetic support, it has superior surface smoothness and durability compared to conventional ones, and also has excellent running stability, reducing output fluctuations and tape It has been found that a magnetic recording medium with significantly less noise can be obtained.

That is, the present invention provides a magnetic recording medium characterized in that a compound represented by the following general formula [I] is contained in a magnetic layer and/or a back coat layer formed on a nonmagnetic support. It is.

In the compound represented by the general formula [I] according to the present invention, R[ is Cm'2m+1-Cm F2m+lSO
2N(R')- or CIIIF2m, C0N(R')
- is a perfluoroalkyl-containing group represented by m
When it is less than 3, it is difficult to obtain the surface characteristics of the magnetic recording medium according to the present invention, and when it exceeds 20, the solubility and dispersibility of the magnetic coating material decrease, which is not preferable.

R3R3 is a polysiloxane chain, but when n is 521 or more, it becomes difficult to dissolve in organic solvents, making it difficult to form into a paint, and the compatibility with binder resins decreases, making it easy to cause blooming, so it is preferable. () Not.

The compound represented by the general formula [I] according to the present invention is a carboxylic acid monoester thereof (wherein A is the same as described above, and R' is an alkyl group or alkenyl group having 1 to 36 carbon atoms). ), succinic anhydride or substituted succinic anhydride or maleic anhydride or phthalic anhydride or phthalic anhydride represented by (where Ro is the same as above) and an alkyl monoalcohol [■] , a perfluoroalkyl group-containing monoalcohol [IV] and a polysiloxane chain-containing monoalcohol [V] are reacted, or a perfluoroalkyl group-containing monoalcohol [IV] and a polysiloxane chain-containing monoalcohol [V] are reacted. It can be obtained by

(The following is a blank space) Specific examples of these raw material compounds include the following.

Hal or [I bl : polyol compound or its carboxylic acid monoester CI (CII2ON) 20H, H-C (CH2011)
3. HOH2C-C(CH20H)3.

(JI3-C(CH20H)3, C2H3-C(CH
20 old 3NO2-C (Ct120tl)3.

N(CH20120H)3, N(CH2C(CH3)
HOH)3.

(2H5 2”5 (IOC2t14) 2N-C2ti40C-C17H
35(HOC2H4)2N-02"40C-015'3
1(t10c2H4)2N-C2H40C-C13H2
7CH3CH30 (HOHCCH2)2 N-CH2Cl-QC-C17
H35CM3CH30 (HOHCCH2)2N-CH2Cl-QC-C15H
31(llOHccH2)2N-CH2Cl-QC-
C13H27 etc. [11] Maleic anhydride, succinic anhydride or substituted succinic anhydride [nl] Alkyl monoalcohol C13H2, C2H501! , C3H7011,C
4HgOH, C3tlBOtlCB) 11701'I,
Cl2H250H, Cl4H29011, C+6H3
30H.

C+8H3yOH, C26H530H, C3+ H63
0H etc. [IV] Perfluoroalkyl group-containing monoalcohol (1) C6F13Ct120H, C6F13CH
2CH20H, C7F15CH20tl.

CBF1□CH20H, C6F13CH2CH20H,
C5F12-+CH2+ffOH.

CgFlg CH2CH20H, CIOF21CH2C
H20H.

ClBF37Ct12CH20t1 etc.C2H3 CBF+7SO2N+CH2Ct120+TrJHCI
2F25SO2N-CH2CH20H, etc. h ph ph ph ph ph CH3 C13C, 8837CH3 Ct13Ph CH3 Cl+, Threat i-0 Radiation≠Xi-0 HanaS Eye CI Old 0HC1l
Ph CH3 C5F, -C-N-C8 OCH20H.

C6F13-CN-CH2CH20H.

C7F15-C-N-CH2CH20H.

C3F1□-C-N-C12C1,OH.

C, F, 1-C-N+CH2CH2O stone [1C8F1□
-C-N+CH2CH20iH [V] Polysiloxane chain-containing monoalcohol C■3CH3 CHCH CHCH CH3Ph CH3 CH3Cl3CH3 C [13th edition i-0←→5i-0 Hanawa I CH dirt QC2H,
OHCH3CgHly Ct13 CH juice 5i-0 bill 5i-0 jet Si÷CM old OC2 KoH
CH3C,8H37CH.

CH3Ph CH3 1 However, ph represents a phenyl group, n or (nl +
n2) is an integer from 1 to 520.

When the compound represented by the general formula [I] according to the present invention is included in the magnetic layer, the amount of addition is 100% of the magnetic powder in the magnetic layer.
O, ooi to 2o heavy most part is preferable for the heavy hanging part,
o, oi to 10 parts by weight are particularly preferred. In addition, when it is included in the back coat layer on the back side of the non-magnetic support, 100 parts by weight of the binder resin in the back coat layer (relative to 0,
01 to 30 parts by weight are preferred, and o, i to 10 parts by weight are particularly preferred. Furthermore, although a decrease in durability cannot be avoided, coating the magnetic layer or the back coat layer on the back side of the non-magnetic support,
When forming, the amount of paint is 1 to 1000 mg.
/Trt is preferred.

Magnetic powders that can be used in the magnetic layer of the magnetic recording medium according to the present invention include 7-Fe2O3, Fe3O4, T-Fe20
Mixed crystal of 3 and Fe3O4, cobalt-doped 7 −
Metals such as Fe2O3 and Fe3O4, chromium dioxide, barium ferrite, Fe, Co, old, 3. Cr,
, Mn.

Examples include alloys containing Bi, M, V, etc., and ferromagnetic powders such as iron nitride.

In addition, as binder resins, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-vinyl chloride copolymer Coalescence, vinyl chloride-acrylonitrile copolymer, acrylic ester-
Acrylonitrile copolymer, acrylic acid ester-nylidene chloride copolymer, methacrylic acid ester-vinylidene chloride copolymer, methacrylic acid ester-styrene copolymer, thermoplastic polyurethane resin, noenoxy resin, polyvinyl fluoride, vinylidene chloride -Acrylonitrile copolymer, butadiene-acrylonitrile copolymer, acrylonitrile-butadiene-acrylic acid copolymer, acrylonitrile-butadiene-methacrylic acid copolymer, polyhinyl butyral, polydonyl acetal, cellulose derivative, styrene-butadiene copolymer Examples include polymers, polyester resins, phenol resins, epoxy resins, thermosetting polyurethane resins, urea resins, melamine resins, alkyd resins, urea formaldehyde resins, and the like.

Furthermore, non-magnetic supports include polyesters such as polyethylene terephthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate and cellulose diacetate, polycarbonate, polyvinyl chloride, polyimide, metal materials such as aluminum and copper, and paper. etc.

On the other hand, a compound represented by the general formula [I] is added to the magnetic layer and/or
Examples of means for incorporating it into the back coat layer include aromatic solvents such as benzene and toluene, halide solvents such as Freon-113,1,1,1-trichloroethane, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexyl A compound represented by general formula [I] is mixed into a magnetic coating liquid and/or binder resin solution using a ketone solvent such as linone, an ester solvent such as ethyl acetate or isobutyl acetate, or a mixture of these solvents. A method of forming a magnetic layer and/or a back coat layer, or a method of mixing in a binder resin in advance, or a method of appropriately dissolving a compound represented by general formula [I] in the above organic solvent system. , a method of coating or spraying this solution onto the surface of a pre-formed magnetic layer and/or backcoat layer, or a method of immersing the magnetic layer and/or backcoat layer in the solution.

Further, the compound represented by the general formula [I] according to the present invention is
Although it can be used in combination with other lubricants, particularly preferred results are obtained when used in combination with higher fatty acids.

[Function] Why does the compound represented by the above general formula [I] according to the present invention improve the lubricity and abrasion resistance of the magnetic layer and/or back coat layer, and create magnetic properties with excellent running stability and durability? It is not clear whether to provide a layer and/or a backcoat layer.

However, in the case of compounds containing only perfluoroalkyl groups or compounds containing only polysiloxane chains, remarkable lubrication performance is not observed, so the coexistence of perfluoroalkyl groups and polysiloxane chains may have some synergistic effect. It is assumed that it will appear.

In addition, the part that does not contain perfluoroalkyl groups and polysiloxane chains has good affinity with the resin component of the magnetic layer, and its anchoring effect is thought to develop sustained lubricity and improve durability. Ru.

Note that these considerations are helpful in understanding the content of the present invention, and of course do not limit the present invention in any way.

[Effects of the Invention] The compound represented by the general formula [I] according to the present invention improves the leveling properties of magnetic paints and/or binder resin solutions, and therefore has a great impact on improving the productivity of magnetic tapes and magnetic disks. Furthermore, since it provides a coated surface with high homogeneity, it is possible to make the magnetic layer and/or back coat layer thinner, which has been particularly required in recent years as tape lengths have become longer. .

In addition, since the magnetic recording medium according to the present invention has excellent lubricity and lubricity sustainability, it can improve the running stability and durability of magnetic tapes, floppy disks, magnetic disks, etc. compared to conventional ones, and To enable playback with little output fluctuation, and also to enable long-time still playback of video tapes and the like.

Next, in order to explain the present invention in more detail, raw material production examples,
Examples and comparative examples are shown, but parts and percentages are shown below.
Unless otherwise specified, all measurements are based on weight.

Raw material production example 1 (Fluorine/silicon coexisting compound-1) 86 parts of glycerin monostearate and 48 parts of succinic anhydride were charged into a 4-ton flask equipped with a stirrer, a condenser, and a thermometer, and the contents were heated under nitrogen gas introduction. 125
After heating to 0.degree. C. to melt, the mixture was further maintained at the same temperature for 10 hours to obtain disuccinic acid half ester of glycerin monostearate. Next, 10.00 parts of disuccinic acid half ester of glycerin monostearate obtained above, 6.66 parts of CgF, 7C2H40H,
CH3CH3 81.36 parts, oyohitoluene 110 parts, concentrated sulfur 11.9 parts
6 parts were charged, and the esterification reaction was carried out for 10 hours while removing condensed water as an azeotrope while refluxing toluene.

After cooling the reaction product to 50°C, calcium hydroxide was added to neutralize the acid component, and insoluble matter was removed by filtration. From the resulting solution, toluene was distilled off to form a fluorine/silicon coexisting compound. -1 was obtained.

Raw Material Production Examples 2 to 8 Various fluorine/silicon coexisting compounds were synthesized in the same manner as Raw Material Production Example 1, except that the raw material composition was changed. Their constituent components are shown in Table-1.

It is indicated by.

Example 1 [Formulation] The above blended composition was kneaded in a ball mill for 72 hours, filtered through a 3μ filter, and then applied onto a polyester film having a thickness of 12IJIn to a dry thickness of 5IIM.

The tape was then subjected to orientation treatment, dried, wound up, surface treated with a super calendar, and cut into a 172-inch width to obtain a magnetic tape.

Examples 2 to 8 Magnetic tapes were obtained in the same manner as in Example 1, except that the fluorine/silicon coexisting compound-1 in the composition described in Example 1 was replaced with the following compound.

Example 2 Fluorine/silicon coexisting compound-2 Example 3
Fluorine/silicon coexisting compound-3 Example 4 Fluorine/silicon coexisting compound-4 Example 5 Fluorine/silicon coexisting compound-5 Example 6 Fluorine/silicon coexisting compound-6
Example 7 Fluorine/silicon coexisting compound-7 Example 8
Fluorine/silicon coexisting compound-8 Example 9 Instead of using 1.0 part of fluorine/silicon coexisting compound-1 in the blended composition described in Example 1, 0.75 part of fluorine/silicon coexisting compound-1 was used. , stearic acid 0.
A magnetic tape was obtained in the same manner as in Example 1 except that 25 parts were used.

Comparative Examples 1 to 8 Magnetic tapes were obtained in the same manner as in Example, except that the fluorine/silicon coexisting compound-1 in the composition described in Example 1 was replaced with the following compound.

Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Fluorine surfactant (Ca F 17302 NCH2C00K ) aH7 Fluorine surfactant CH3 Dimethyl silicone oil ()fW#4000) (KF −
96: Shin-Etsu Chemical Co., Ltd.) Lecithin stearate Liquid paraffin Ctt2υCG2H4C0C2H4C8F17 Comparative example 8 (0 phrase 12) Regarding each magnetic tape obtained as described above,
The coefficient of dynamic friction (ie, lubricity and lubricity persistence), running stability, and durability were measured. The results are shown in Table-2.

Note that the dynamic friction coefficient is the dynamic friction coefficient μ with respect to the magnetic head during the first run, 1, and the dynamic friction coefficient μ after 500 runs.
I asked about 500.

Running stability is determined by judging running unevenness from the image when running on a video deck, and ranks into 5 levels (5: No uneven running, 4: Slight uneven running, 3: Slight uneven running,
Evaluation was made as follows: 2: There is uneven running; 1: The uneven running is noticeable.

The durability test was conducted under the conditions of 40' (:, 85% RTL), a head load of 10 g, and a running speed of 4.8 C.
After running 500 times at m/sec, it was regenerated and evaluated by measuring the output fluctuation value with respect to the initial output.

Table 2 (blank below) Example 10 [Formulation] After mixing the above blended composition, 20 parts of Desmodur L (manufactured by Bayer AG) was added to prepare a back coat paint. This paint was applied to the back surface of the magnetic layer coated film prepared in Comparative Example 4 so that the thickness after drying was 3 μm to form a back coat layer.

The characteristics of the obtained magnetic tape are 1 = 0.12 for μ and 5 for μ.
00"""= 12, driving stability 5, output fluctuation 0.2
It was dB.

Example 11 In the back coat paint formulation used in Example 10,
A paint obtained by using fluorine/silicon coexisting compound-2 instead of fluorine/silicon coexisting compound-1 was prepared from the blended composition of Example 1 by using fluorine/silicon coexisting compound-2.
A back coat layer was formed by coating the back surface of the magnetic layer coated film, which had been subjected to IH except for No. 1, to a thickness of 3 μm after drying.

The characteristics of the obtained magnetic tape are: 1 = 0.12 for μ, 5oo = 0.13 for μ, running stability 4, and output fluctuation 0.2 dB.
Met.

As is clear from the results of Table 2 and Example 10.11, the magnetic layer obtained by forming the magnetic layer and/or back coat layer containing the fluorine/silicon coexisting compound according to the present invention on a nonmagnetic support. Compared to those containing conventional additives, the recording medium has excellent ability to reduce dynamic frictional resistance, and has a small difference in μ of 1 and μ of 500, as well as small output fluctuations, resulting in improved surface lubricity and running stability. It was confirmed that the material had excellent strength and durability.

Claims (1)

[Claims] (1) A magnetic recording medium characterized in that a compound represented by the following general formula [I] is contained in a magnetic layer and/or a back coat layer formed on a nonmagnetic support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [In the formula, A is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, Z is a hydrogen atom, hydroxymethyl group, methyl group, ethyl group or nitro group), or ▲ formula,
There are chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ It is a trivalent linking group represented by. For X_1, A divalent linking group represented by ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and they may be the same or different. Y_1 and Y_2 have ▲mathematical formulas, chemical formulas, tables, etc.▼,
▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables, etc.▼ (However, l_1 is an integer greater than or equal to 1), or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, l_2 and l_3 are integers greater than or equal to 0, and they cannot be 0 at the same time. (l_4 is an integer of 3 or more) and may be the same or different. Rx is a hydroxyl group, or an alkyl group, alkenyl group, alkoxy group, or alkenyloxy group having 1 to 36 carbon atoms. R_f is C_mF_2_m_+_1-, C_mF_2_m_+_1SO_2N(R')- or C_mF_2_m_+_1CON(R')- (wherein, m is an integer of 3 to 20, and R' is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms). It is a perfluoroalkyl-containing group represented by R_S_i has ▲mathematical formulas, chemical formulas, tables, etc.▼(However, R_1 is a methyl group or phenyl group, and R_2
, R_3 is an alkyl group or phenyl group having 1 to 20 carbon atoms, which may be the same or different, and may be the same or different for each siloxy unit, and n is 1 to 520
is an integer of ). ]