JPS62262223A - Magnetic recording medium having magnetic layer containing phthalocyanine onium salt - Google Patents

Abstract

PURPOSE:To improve the dispersibility of magnetic powder, output, S/N and stagnation stability by incorporating a phthalocyanine onium salt into a magnetic layer. CONSTITUTION:This recording medium contains the phthalocyanine onium salt in the magnetic layer. An example of the phthalocyanine onium salt includes a compd. in which the onium salt formed by oxygen, sulfur, nitrogen, phosphorus, etc. having isolated electron pairs is introduced generally via a combination group of a methylene group, etc., into the benzene ring on the outside of a tetrabenztetraazaporphine nucleus (phthalocyanine group). The dispersibility is thereby improved, and the high output and high S/N ratio is obtd.; further the movement in the magnetic layer is sealed and the generation of a trouble such as blooming is obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic recording medium such as a magnetic tape, a magnetic sheet, or a magnetic disk.

(Prior art) Generally magnetic recording media (hereinafter typically referred to as magnetic tape)
is made by applying a magnetic paint containing magnetic powder, binder, etc. to a support and drying it.

When preparing magnetic paints used in manufacturing such magnetic tapes, various dispersants are used to disperse magnetic powder together with a binder in an organic solvent.

/ Mausoleum, z 1. J ko ＾ JA J I ノ ＋
+mLl+ l+ ---L--Box zJ I
/ +J+unsaturated fatty acids, and salts of these fatty acids,
Hydrocarbons having a polyoxyethylene chain, sulfuric esters or phosphoric esters of higher alcohols, etc. have been variously tried and put to practical use in order to improve the dispersibility of magnetic powders. These dispersants are generally used in an amount of 0.01 to 2 OWt parts per 100 parts of the magnetic powder (hereinafter referred to as wt parts).

On the other hand, in order to prepare high-density recording and high-performance magnetic tapes that are required in recent years, the i-fine particles of magnetic powder and the specific surface area (ag'r value)
Therefore, it is difficult to obtain magnetic tapes with desired characteristics using conventional dispersants and related technologies. - Also, electromagnetic conversion characteristics or tape physical properties include the particle size and specific surface area of magnetic powder or various filler particles contained in the magnetic layer and other magnetic tape constituent layers, such as carbon black used for antistatic purposes, and specific surface area CBET.
The BET value of the magnetic powder is greatly influenced by the value (2 units m"/gr), and a large BET value of the magnetic powder is required in terms of electromagnetic conversion characteristics and recording density. However, a large BET value is due to the dispersion of the magnetic powder or various fillers. In order to overcome these difficulties and inconveniences, it has a repeating unit of -(CH2Cl,0)n- and the terminal is an (alkyl group) -0(-C
H2CH20) n- phosphoric acid ester is well known as a dispersant, but as magnetic powder becomes finer and higher densities are required, this ester becomes more important in terms of magnetic media performance. Dispersion, etc. will also be insufficient if such phosphoric esters or a combination of phosphoric esters and lecithin are used.

On the other hand, as an example of using carbon black dispersed in a resin, as a resin coloring method using carbon black, a sulfonamide-substituted metal phthalocyanine pigment has a color masking effect on carbon black and its dispersion. There is a description that it increases
According to our study, the dispersing power of the phthalocyanine for magnetic powder is not sufficient.

(Objectives of the Invention) The objects of the present invention are: +1) Providing a novel dispersant with excellent dispersibility of magnetic powder;
(2) Providing magnetic recording media with excellent output, (3)
The present invention aims to provide a magnetic recording medium with an excellent S/N ratio, and (4) to provide a magnetic recording medium that uses a magnetic coating material with good stagnation stability, and therefore has good productivity.

(Structure of the Invention) The object of the present invention is to provide a magnetic layer containing a magnetic powder and a binder provided on a support, which is characterized in that the magnetic layer contains a phthalocyanine onium salt. Achieved by recording media.

Next, the present invention will be explained in detail.

Examples of phthalocyanine onium salts according to the present invention include oxygen, sulfur, nitrogen, etc., which have a lone pair of electrons, generally through a linking group such as a methylene group on the outer benzene ring of the tetrabenztetraazaporphine nucleus (phthalocyanine group). Examples include compounds represented by the following general formula (I) into which an onium salt made of phosphorus or the like is introduced.

General formula CI) (MePc + (-B - (U) )

K * Be + Mg * Ca + Ba + C
d, Hg + Cr + F'e + Co +)J
+ * Cu + Zn r P t e Pd or v
O is preferably used.

-E-8-([J):] is an onium salt residue, B is a divalent linking group, and -CH2-, -3-, -0-1-CO
-, -so, -.

-CH25- and the like can be mentioned, but depending on the form of the onium salt, this is not always necessary. (U) is an atomic group that can contain atoms such as O, S, N, and P to form an onium salt. m is an integer from 1 to 4. Further, Xo is an anion for maintaining electrical neutrality of the phthalocyanine onium salt, and is a halogen ion, a sulfonic acid ion, or the like.

Examples of the phthalocyanine onium salts according to the present invention include ammonium salts (including amine salts), k'IJ dinium salts, intiuronium salts, tetramethylthiuronium salts, and tetrasulfonium salts.

Among these, ammonium salts are preferred from the viewpoint of dispersibility of the magnetic powder, and ammonium salts derived from tertiary amines and ammonium salts derived from cyclic amines such as pyridine are preferred.

The phthalocyanine onium salt according to the present invention provides excellent dispersibility to magnetic powder, and the improved dispersibility is confirmed by microscopic observation, and as a result, high output and high S/N ratio appear. Furthermore, movement within the magnetic layer is blocked, and problems such as pluming do not occur.

The phthalocyanine onium salt according to the present invention can be synthesized according to conventional methods.

For example, phthalocyanine tetramethylthiuronium salt is
Fill copper phthalocyanine CI B + N (C
Chloromethylation using (CH2Cl)zO in the presence of 2Hs)s and substitution of the chlorine with tetramethylthiourea and other onium salts are similarly synthesized by conventional methods.

Many documents can be consulted for other specific examples and synthetic methods of the phthalocyanine onium salt according to the present invention.

Other examples of phthalocyanine onium salts according to the present invention include, for example, "Tertiary and Quaternary Compounds J" (pages 226 to 230) described in "Phthalocyanine Compounds" (Proceedings of the American Chemical Society; Reinhardt Publishing Co., Ltd., 1963). ), British Patent No. 844,338, British Patent No. 530°881, British Patent No. 586
, No. 340, No. 587.636, U.S. Patent No. 2,227
．． No. 628, No. 2,542.327, No. 2,542.
Examples include those described in No. 328 and the like. In addition, onium salts of phthalocyanines described in other than the "tertiary and quaternary compounds" section of "phthalocyanine compounds" can also be used in the present invention.

The phthalocyanine onium salt according to the present invention comprises magnetic powder 1
It can be used in the range of 0.01 to LOwt% with respect to 00wt%, preferably bx o, o s to 7 w
It is in the range of t%.

The phthalocyanine onium salt may be used by pretreating the magnetic powder, or may be used by being added to the magnetic paint together with other components, and there are no particular limitations on the method of use.

In the present invention, conventional techniques can be used to form the magnetic layer, back coat layer, or other constituent layers of the magnetic tape of the present invention.

The magnetic layer of the magnetic tape of the present invention may be a coated magnetic layer using magnetic powder, binder, dispersion, lubricant, etc., or may be formed by a vapor deposition method, a sputtering method, a paper deposition method, etc. It may be a thin film type magnetic layer.

Examples of magnetic materials include r-Fe201. co containing r
-Fe203, Co coated r-Fe203 + F
e3O4* Co-containing Fe3O4 + Co-coated Fe3O4
, Co-containing magnetic fl Feox (2>x>3)
Oxide magnetic materials such as Cr02, e.g. Fe, Ni,
Co.

Fe-Ni alloy + Fe-Co alloy, Fe-k1 alloy,
Fe-Al-Ni alloy + Fe-Ni-P alloy, Fe-Ni-Co alloy, Fe-Mn-Zn
Alloy, Fe-Ni-Zn alloy, Fe-Co-
Ni-Cr alloy, Fe-Co-Ni-P alloy, Co-
Ni alloy + Co-P alloy, C6-Cr alloy, etc. Fe, N
Examples include various ferromagnetic materials such as i+Co and metal magnetic powder containing Al as a main component. Additives to these metal magnetic materials include Sl + cu l zn l Al + P
, Mn, Cr, or a compound thereof. Hexagonal ferrite such as barium ferrite, nitrogen iron, and iron carbide are also used.

Binders used in magnetic layers or back coat layers (
Examples of the binder include abrasion-resistant polyurethane. This has strong adhesion to other substances,
It is mechanically strong and can withstand repeated stress or bending, and has good abrasion resistance and weather resistance.

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

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

Phenoxyfil fat can also be used.

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

These advantages are complementary to the above-mentioned polyurethane, and also help each other to significantly improve the stability over time in the physical properties of the tape.

In addition to the binders described above, resins generally used in magnetic recording media, various modified resins with hydrophilic groups such as sulfo groups, phospho groups, and carboxy groups, thermoplastic resins with characteristic behavior, and thermosetting resins. Mixtures of resins, reactive resins, and electron beam curable resins may also be used.

In order to improve the durability of the magnetic layer of the magnetic tape of the present invention, the magnetic paint can contain various curing agents, such as incyanate.

Aromatic incyanates that can be used include, for example, tolylene diincyanate (TDI) and adducts of these incyanates and active hydrogen compounds, and those with an average molecular weight in the range of 100 to 3,000 are preferable. It is.

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

The magnetic paint used to form the magnetic layer may contain additives other than phthalocyanine onium salts, such as dispersants, lubricants, abrasives, other fillers, and antistatic agents, if necessary. Good too.

Examples of dispersants include lecithin, phosphate varnish FK, amine compounds, alkyl sulfates, fatty acid amides, higher alcohols, polyethylene oxides, sulfosuccinic acid, sulfosuccinates, known surfactants, and salts thereof. Salts of polymeric dispersants containing ffl acids (eg, carboxy, sulfo, phospho groups) can also be used. These dispersants may be used alone or in combination of two or more. These dispersants are added in an amount of 0.1 to m parts by weight per 100 parts of the binder. These dispersants can also be used to pre-treat the magnetic powder.

Further, as the lubricant, silicone oil, graphite, carbon black graft polymer, molybdenum disulfide, tungsten disulfide, fatty acids such as lauric acid and myristic acid, fatty acid esters, etc. can be used. Are these lubricants 100% binder? 0.2 to 20 per part of li
It is added in an amount of t i parts.

As the abrasive, commonly used materials include fused alumina (preferably α-alumina), silicon carbide, chromium oxide, α-iron oxide, titanium oxide, silicon nitride, aluminum nitride, boron nitride, corundum, artificial corundum, Diamonds, artificial diamonds, garnet, emery (main ingredients: corundum and magnetite), etc. are used. These abrasives have an average particle size of 0.05 to 5 μm, particularly preferably 0.1 to 2 μm. These abrasives are used in an amount of 1 to 2 ONt per 100 parts by weight of the binder.
It is added within the range of 100%.

As other fillers, organic powders or inorganic powders may be used in combination or in combination.

As the organic powder that may be used in the present invention, acrylic styrene resin, benzoguanamine resin powder, melamine resin powder, and phthalocyanine pigment are preferable, but polyolefin resin powder, polyester resin powder, polyamide resin powder, and polyimide are preferred. Resin powders, polyfluoroethylene resin powders, etc. can also be used, and inorganic powders include silicon oxide, titanium oxide, aluminum oxide, calcium carbonate, barium sulfate, zinc oxide, tin oxide, calcium carbide, Merck, kaolin, calcium sulfate, and fluoride. Examples include zinc chloride and molybdenum dioxide.

As antistatic agents, conductive powders such as carbon black hash, graphite, tin oxide-antimony oxide compounds, titanium oxide-tin oxide-antimono oxide compounds; natural surfactants such as saponin; alkylene oxides, Nonionic surfactants such as glycerin and glycidol; cationic surfactants such as higher alkyl amines, quaternary ammonium salts, pyridine, heterocycles, phosphonium or sulfonium; carboxylic acids, sulfonic acids, phosphoric acids Examples include anionic surfactants containing acidic groups such as sulfuric acid ester groups and phosphoric acid ester groups; amphoteric surfactants such as amino acids, aminosulfonic acids, and sulfuric acid or phosphoric acid esters of amino alcohols.

Solvents to be added to the above paint or diluting solvents during application of this paint include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, propatool, and butanol; methyl acetate, ethyl acetate, butyl acetate,
Esters such as ethyl lactate and ethylene glycol monoacetate; ethers such as glycol dimethyl ether, glycol monoethyl ether, dioxane, and tetrahydrofuran; and aromatic hydrocarbons such as benzene, toluene, and xylene can be used.

In addition, as a support, polyethylene terephthalate,
Examples include polyesters such as polyethylene-2,6-naphthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate and cellulose diacetate, plastics such as polyamide and polycarbonate, metals such as Cu * Al + Zn, and glass. , Bn.

Ceramics such as Si carbide, porcelain, and earthenware can also be used.

The thickness of these supports is about 3 to 100 μm in the case of a film or sheet, preferably 5 to 50 μm,
In case of disk or card shape, add μm to l.

In the case of a drum shape, a cylindrical shape is used, and the shape is determined depending on the recorder used.

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

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

(Example) The present invention will be specifically explained using examples.

Example 1 and Comparative Examples 11+, +2) Magnetic paints were prepared according to the formulations shown in Table 1 below.

[Magnetic paint formulation]

Table-1 ”[CuPc+i”SO,NH(CH9)Iff C
! (ti.

The components shown in Table 1 were placed in a ball mill and dispersed. After filtering the magnetic paint through a 1 μm filter, 5 parts of polyfunctional incyanate was added, and the mixture was coated onto a support to a thickness of 5 μm using a reverse roll coater. Example Sample 1 and Comparative Example Sample F
l), +21.

Table 2 shows the performance of the videotape samples obtained above.

Table 2 Table 2 is a relative evaluation based on the performance of Comparative Example (2). In addition, a good winding appearance indicates that the tape running properties are stable.

Furthermore, the magnetic paints of these samples showed remarkable superiority in terms of productivity.

Comparative sample (2) magnetic paint, which used lecithin as a dispersant, showed a significant increase in viscosity in a 24-hour stagnation stability test without the addition of a hardening agent (polyfunctional isocyanate), causing problems in production. The videotape obtained by coating after stagnation is the comparison sample (2) of stagnation O. Compared with K, Rf specific output Lumi S/
Both N values decreased by more than 2 tia. Also comparative sample +1
1 has poor initial performance and further KRf due to stagnation.
The output and Lumi S/N both decrease by 1 dB or more.

Compared to these comparative samples, the sample coated after stagnation obtained in Example 1 shows almost no deterioration in performance. , we were able to make a significant contribution to improving productivity and advance toward high-density, high-performance magnetic recording.

Claims (1)

[Claims] A magnetic recording medium characterized in that a magnetic layer containing magnetic powder and a binder provided on a support contains a phthalocyanine onium salt.