JPH03216813A - Magnetic coating material and magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent dropout of a magnetic layer without using a base coating material by incorporating a titanium coupling agent and a surface modifier for the supporting body into the magnetic coating material. CONSTITUTION:The magnetic coating material to form a magnetic layer on a supporting body contains at least one kind of titanium coupling agent and one kind of surface modifier, respectively. By coating this magnetic coating material on the supporting body, wettability for the supporting body can be improved and the dried magnetic layer has higher adhesion property. Moreover, bonding strength of the binder and magnetic powder in the magnetic layer can be increased to raise the strength of the layer. Thereby, dropout of the layer can be prevented and the layer can be formed at low cost since no base coating material is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention particularly relates to a magnetic recording medium in which falling off of a magnetic layer from a support is reduced.

BACKGROUND OF THE INVENTION Magnetic recording media such as magnetic tapes and magnetic disks are widely used in the video field, audio field, computer field, and the like. Coating-type magnetic recording media, in which a magnetic coating consisting of magnetic powder, resin, solvent, dispersant, and other additives is applied to a support and dried to form a magnetic coating, are also used as such magnetic recording media. ing.

In recent years, magnetic recording media have been required to have higher recording densities as well as higher reliability, and for this reason, magnetic layers have been formed by fine-graining magnetic powder and filling it with high density. Efforts have been made to make the magnetic layer thinner and to improve the running properties of the magnetic layer.

However, when such improvements are made to the magnetic layer, the adhesion of the magnetic layer to the support, the strength of the magnetic layer, etc. decrease, and the magnetic layer tends to fall off when used as a magnetic recording medium. . Specifically, when used as a magnetic tape, for example, the magnetic layer peels off from the support due to being rubbed by a magnetic head or the like, causing deterioration of the characteristics of the magnetic tape such as increased dropout. Moreover, the peeled off particles may adhere to the magnetic head and cause damage thereto.

In order to prevent these problems, conventionally, an undercoat consisting of a resin solution made by dissolving polyester resin, polyurethane resin, etc. in an organic solvent is applied onto the support, and then a borous paint is applied on top of the coating to form the magnetic layer. It is also being formed.

[Problem to be solved by the invention]

However, when applying an undercoat as described above onto a support and then applying a magnetic paint onto the dried paint film, the I3I-containing solvent contained in the magnetic paint may cause the undercoat film to swell. Dissolution may impair the smoothness of the interface between the magnetic layer and the coating film of the undercoat, and this may cause a decrease in the smoothness of the surface of the magnetic layer. As a result, problems such as a decrease in output and an increase in output fluctuation occur.

At this time, a polyisocyanate compound is added to the primer,
Another method has been used to crosslink the resin in the base coat film and apply magnetic paint on top of it to prevent it from swelling or melting due to solvents, but this method has not yet been shown to be sufficiently effective. Not yet. In addition, providing a coat of primer in this way increases the number of production lines and increases material costs, resulting in high costs and, as in the case of magnetic tape, for example,
This is not desirable in the current situation where jli ratings are getting lower. An object of the present invention is to provide an inexpensive magnetic recording medium that prevents the magnetic layer from falling off without using an undercoat.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a magnetic paint for forming a magnetic layer on a support, in which a titanium coupling agent and an interface modifier for the support on which the magnetic paint is applied are respectively added. The present invention provides a magnetic paint characterized by containing at least one type of magnetic paint, and a magnetic recording medium using the same. At this time, 0.1 to 5 parts of the titanium cassopring agent and surfactant are each added to 100 parts by weight of the magnetic powder.
The content is preferably 0 parts by weight.

Next, the present invention will be explained in detail.

When using a magnetic recording medium in which a magnetic layer is formed by coating and drying a magnetic paint on a support, the magnetic layer may fall off due to two reasons: ■ Decrease in the adhesion of the magnetic layer to the support, ■ Deterioration of the magnetic layer within the magnetic layer. This is a decrease in strength. Therefore, it is necessary to make improvements from these two points.

In view of the above point (1), the present invention adds an interface modifier for the support to the magnetic paint, improves the wetting of the support when the magnetic paint is applied to the support, and in view of the above point (2), the present invention improves the wetting of the support. A ring agent is contained in the magnetic layer to strengthen the bond between the binder and the magnetic powder and improve its strength.

Examples of the titanium fubbling agent include the following.

(1'Sobropyl triisostearyl titanate) (
Isopropyl tritodecyl benzenesulfonyl titanate) 0H (Isobrobyl trisdioctyl piophosphate titanate) (Bisdioctyl bipolar phosphate titanate) CH, j CH3-CH -0-Ti-←0-(4}14-N }I
-C2H4-NH2)3 (isopropyl triN-amitoethylaminoethyl titanate) Other titanium coupling agents can also be used, and these may be used alone or in combination of two or more.

Moreover, the following can be mentioned as the above-mentioned interface modifier.

(b) Amines Beef tallow diamine dioleate Coconut diamine, diadipate, etc. These may be used alone or in combination.

(1) Phosphate esters Monoesters of the following general formula (1) (wherein R-0- is a phenol group, nonylphenol group, dinonylphenol group, tridecylphenol group, oleyl alcohol group, stearyl alcohol group, etc., n represents 2 to 15.) A diester of the following general formula (II) (wherein R'-0- and R2-0- are the same or different phenol group, nonylphenol group, dinonylphenol group, tridecylphenol group, oleyl alcohol group,
stearyl alcohol group, etc., n and m are the same or different 2
~15. ) These monoesters and diesters may be used alone or in combination.

(3) Soybean lecithin (2) Fatty acids, valmitic acid, stearic acid, etc. Two or more of the above interface modifiers (a) to (2) may be used as a mixture.

The above titanium coupling agent and interface modifier are each 0.05 to 10.0 parts by weight per 100 parts by weight of magnetic powder.
It is preferably used in a proportion of 0.1 to 5.0 parts by weight.

If it is too small, the effect of preventing magnetic powder from falling off from the magnetic layer will be low, and if it is too large, blooming etc. will occur, which is not preferable.

A silane cassoplating agent and/or an aluminum-based camping agent may be used in combination with the titanium cassopling agent, and the aluminum cassopling agent may include, for example, CH3! CH3 (in the formula, R represents a hydrocarbon group), etc., and one type or two or more types are used in combination.

In addition, the silane cuff pulling agent includes a vinyltrimethoxysilane coupling agent, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane cuff pulling agent,
Examples include γ-aminopropyltriethoxysilane coupling agent, γ-(2-aminoethyl)aminopropyltriethoxysilane coupling agent, γ-merikabutopyltrimethoxysilane coupling agent, etc. One or two types The above are used together.

Examples of the binder resin used in the magnetic recording medium of the present invention include vinyl chloride-vinyl acetate copolymer, vinyl chloride-hinyl acetate copolymer-vinyl alcohol copolymer,
Vinyl chloride-vinylidene acetate maleic acid copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylic ester-acrylonitrile copolymer, acrylic ester-vinylidene chloride copolymer, methacrylic ester-vinylidene chloride copolymer Polymer, methacrylic acid ester-styrene copolymer, thermoplastic polyurethane resin, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, butadiene-acrylic nitrile copolymer, acrylonitrile-butadiene-methacrylic acid copolymer, polyamide resin , polyvinyl butyral, cellulose derivatives, styrene-butadiene copolymers, polyester resins, synthetic rubbers such as polybutadiene, and other resins.

Thermosetting resins are also used, such as phenolic resins,
Epoxy resin, thermosetting polyurethane resin, urea resin,
Melamine resin, alkyd resin/urea-formaldehyde resin, silicone resin, acrylic reaction resin, epoxy bolyamide resin, nitrocellulose-melamine resin,
Examples include mixtures of high molecular weight polyester resins and isocyanate brevolimers, mixtures of polyester polyols and polyisocyanates, urea formaldehyde resins, mixtures of low molecular weight glycols/high molecular weight diols/triphenylmethane triisocyanate, polyamine resins, and mixtures thereof. Among these, it is preferable to use a combination of those that have good dispersibility in ferromagnetic powder.

In addition, as magnetic powder, γ-Fe2J, 7-Fe20
3 and Fe304 crystal, Cr02, cobalt coated r
-Fe205 or Fe504, etc. Also,
Non-oxide magnetic powders such as metal magnetic powders, gold nitride M magnetic powders, and gold carbide magnetic powders can also be used, and both can also be used in combination.

In addition to the above-mentioned binder resin and magnetic powder, the magnetic paint also contains an organic solvent, and the magnetic paint further contains dispersants, abrasives, fillers, antistatic agents, rust preventives, fungicides, etc. as necessary. Each component is appropriately selected and mixed. A known method is used as the manufacturing method.

This magnetic powder is applied to a support such as a polyethylene terephthalate film (PET film) using a known coating method such as Dr.Frede, reverse roll, gravure roll, or spinner coat, and the magnetic powder is oriented and dried depending on the application. A magnetic recording medium is obtained by performing surface smoothing treatment.

[Effect]

When the magnetic layer contains a titanium coupling agent, the binder of the magnetic layer and the magnetic powder are strongly bonded, and the strength inside the magnetic layer can be increased. In addition, since the magnetic paint contains an interface modifier, it is possible to improve the wetting of the paint when it is applied to the support, thereby increasing the adhesion between the magnetic layer and the support. Example] Next, an example of the present invention will be described.

Example I CO containing r -Fe205 10O
i quantity<BET 45mlg, Hc=800 0e
), 5.0 parts by weight of an aqueous solution of (isoprobyl triisostearyl titanate) pure water was added, and the mixture was stirred and mixed using a Henschel mixer for 30 minutes. Thereafter, it was dried at 100°C for 1 hour. The following paints were manufactured using the obtained surface-treated magnetic powder.

Treated magnetic powder: 100 parts by weight Nonylphenyl group-containing 0.5 parts by weight Phosphate ester Vinyl chloride-vinyl acetate copolymer resin IO parts by weight Polyurethane resin 10 parts by weight Carbon blank 3 parts by weight Alumina
5 parts by weight methyl ethyl ketone
100 ffi parts toluene
100 parts by weight Hexanone 100
Part by weight The above formulation was mixed in a ball mill for 10 hours,
A magnetic paint was obtained after filtration with a μm filter.

This magnetic paint was applied on a PET film treated with 1) μm corona discharge, oriented in a magnetic field, dried, and further calendered to produce a magnetic tape.

An adhesion test and a durability test were conducted on this, and the results are shown in the table.

The test method is as follows.

[Adhesion test]

Cellotape was attached to the magnetic layer side of a magnetic tape slit to a width of 3.81 fi, and the peeling strength of the magnetic layer from the PET film was measured using a constant extension type tensile tester.

[Durability test]

Using a stationary deck, input a 1OKHz, OdH signal, repeat playback, and measure the number of times until the output drops by -1dB or more.

Example 2 In Example 1, 3. Part by weight of O, phosphoric acid ester having a nonylphenyl group3. A magnetic paint was prepared in the same manner except that Offi parts were used, and a magnetic tape was produced using this in the same manner as in Example 1. This was also measured in the same manner as in Example 1, and the results are shown in the table.

Example 3 In Example 1, the magnetic powder was not treated with the isoprobil triisostearate coupling agent and pure water, but the isoprobil triisostearate coupling agent and the magnetic powder were directly converted into a fallout. A magnetic paint was prepared in the same manner except for the blending, and a magnetic tape was produced using this in the same manner as in Example 1. This was also measured in the same manner as in Example 1, and the results are shown in the table.

Example 4 In Example 1, instead of 0.5 parts by weight of the isoprobyl triisostearyl titanate coupling agent, 0 (isobrobyl triisostearyl titanate) was added.
．． 5 parts by weight, CH3 "CH3-CH -0-Ti→0-C2H4-NH-C2
A magnetic paint was prepared in the same manner as in Example 1, except that 0.5 parts by weight of H4-NHz-)5 (isobrobyltriN-amidoethylaminoethyl titanate) was used. A magnetic tape was manufactured using the following steps. This was also measured in the same manner as in Example 1, and the results are shown in the table.

Example 5 In Example 4, instead of 0.5 parts by weight of the phosphoric acid ester having a nonylphenyl group, 0.5 parts by weight of the phosphoric acid ester having a nonylphenyl group and beef tallow diamine.
A magnetic paint was prepared in the same manner except that 0.5 parts by weight of dioleate was used, and a magnetic tape was produced using this in the same manner as in Example 1. This was also measured in the same manner as in Example 1. The results are shown in the table.

Example 6 The procedure of Example 1 was repeated except that 0.5 parts by weight of (bisdioctyl pi-phosphate oxyacetate titanate) was used instead of 0.5 parts by weight of the isobrobyl triisostearyl titanate coupling agent. A magnetic paint was prepared, and a magnetic tape was manufactured using this in the same manner as in Example 1. This was also measured in the same manner as in Example 1, and the results are shown in the table.

Comparative Example 1 A magnetic paint was prepared in the same manner as in Example 1, except that untreated magnetic powder was used instead of the magnetic powder treated with the isobrobil triisostearate coupling agent and pure water. Using this, a magnetic tape was produced in the same manner as in Example 1. This was also determined in the same manner as in Example 1, and the results are shown in the table.

Comparative Example 2 A magnetic coating material was prepared in the same manner as in Example 1 except that the phosphoric acid ester having a nonylphenyl group was not used, and a magnetic tape was prepared in the same manner as in Example 1 using this paint. This was also measured in the same manner as in Example 1, and the results are shown in the table.

Comparative Example 3 A magnetic paint was prepared in the same manner as in Comparative Example 1, except that the phosphoric acid ester having a nonylphenyl group was not used, and a magnetic tape was produced using this in the same manner as in Example 1. This was also measured in the same manner as in Example 1, and the results are shown in the table.

From the results in the table above, it can be seen that the examples have good adhesion.

〔Effect of the invention〕

According to the present invention, it is possible to provide a magnetic paint containing a titanium coupling agent and an interface modifier for the support, so that when this magnetic paint is applied to the support, wetting to the support is improved, and the drying property of the magnetic paint is improved. The adhesion of the magnetic layer can be improved, and the binding force between the binder and the magnetic powder inside the magnetic layer can be increased to increase its strength. This makes it possible to prevent the magnetic layer from falling off even when used as a magnetic recording medium, and since no primer is used, it is possible to provide an inexpensive magnetic recording medium.

January 23, 1990

Claims (3)

[Claims] (1) A magnetic paint for forming a magnetic layer on a support, characterized in that it contains at least one titanium coupling agent and at least one interface modifier for the support to which the magnetic paint is applied. magnetic paint. (2) The magnetic paint according to claim 1, wherein the titanium coupling agent and the interface modifier are each contained in a ratio of 0.1 to 5.0 parts by weight per 100 parts by weight of the magnetic powder. (3) A magnetic recording medium obtained using the magnetic paint according to claim 1 or 2.