JPH05163464A - Coating liquid for forming film, its production and substrate with film - Google Patents

Abstract

PURPOSE:To obtain the subject coating liquid capable of forming a film, having uniform unevennesses and excellent in durability on a substrate by including inorganic colloidal particles and a specific film-forming component in an organic solvent and reducing the ionic concentration. CONSTITUTION:The objective coating liquid containing (A) colloidal particles of an inorganic compound (e.g. colloidal particles of silica), (B) a partial hydrolyzate of a compound selected from acetylacetonato chelates (preferably dibutoxy-bisacetylacetonatozirconium, etc.), alkoxysilanes (preferably tetramethoxysilane, etc.) and metallic alkoxides (preferably tetrabutoxyzirconium, etc.) in (C) an organic solvent. The ionic concentration in the coating liquid is <=1mmol/l. This coating liquid is prepared by subjecting any of a sol containing the component (A), a liquid containing the component (B) and a film-forming coating liquid prepared by adding the components (A) and (B) to the component (C) to treatment with a cation exchange resin and anion exchange resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating solution for forming a coating film, a method for producing the coating solution, and a coated substrate having a coating film formed from the coating solution on a substrate. More specifically, it has uniform unevenness. A coating solution for forming a coating capable of simultaneously forming a coating having excellent durability, a method for producing the coating, and a coating base for a magnetic disk, a magneto-optical disk, an antireflection plate, or the like in which such a coating is laminated on a substrate. Regarding materials

[0002]

TECHNICAL BACKGROUND OF THE INVENTION Conventionally, a coating composition for forming a concavo-convex film capable of imparting durability, scratch resistance and the like to a surface of a substrate made of glass, plastic, metal or the like and at the same time preventing glare has been developed. There is. For example,
Japanese Unexamined Patent Publication No. 2-3468 discloses a general formula RSi (O
R ¹ ) ₃ (wherein R is a hydrocarbon group having 1 to 6 carbon atoms, and R ¹ is an alkyl group having 1 to 6 carbon atoms), and 100 parts by weight of a trialkoxysilane and the general formula Si
(OR ² ) ₄ (in the formula, R ² is an alkyl group having 1 to 6 carbon atoms) tetraalkoxysilane 20 to
Such a coating composition is described which comprises a partial condensate of an organosilicon compound consisting of 130 parts by weight and silica particles.

Also, when manufacturing a magnetic recording medium such as a magnetic disk, a coating solution for forming a coating film, which is composed of a mixed solution of a colloidal solution containing fine particles of inorganic oxide and tetrahydroxysilane (JP-A-61-2229227). JP-A-64-33724, JP-A-2-137120, etc.) are used. A coated magnetic recording medium such as a magnetic disk or a magneto-optical disk formed using such a coating solution for forming a coating has fine irregularities on the surface and has a smooth surface as compared with a magnetic recording medium. The static friction coefficient, which represents the magnitude of the frictional force generated between the magnetic head and the recording device or the reproducing device, is low.

However, the coated substrate obtained from the conventional coating solution for forming a coating as described above has an uneven distribution of the fine particles of inorganic oxide contained in the coating, and moreover, this inorganic oxide. Particles may aggregate with each other,
For this reason, there is a problem in that the unevenness formed on the surface of the coated substrate becomes uneven. That is, there is a problem that the intervals and heights of the convex portions formed by the inorganic oxide fine particles become uneven.

If the irregularities formed on the surface of the coated magnetic recording medium are not uniform, the coefficient of static friction and the magnetic disk generated when the magnetic head slides on the surface of the magnetic recording medium in the recording device or the reproducing device. The surface roughness tends to increase. Particularly, recently, the recording density of the magnetic recording medium has been increased, and along with this, the flying height of the magnetic head, that is, the distance between the magnetic recording medium and the magnetic head during recording / reproduction,
It has become smaller and has recently been set to 0.3 μm or less. For this reason, there is a demand for a coated magnetic recording medium having a more uniform unevenness on the surface.

Under such circumstances, the present inventors have found that a coating solution for forming a coating capable of forming a coating having uniform unevenness and excellent durability on a substrate, and such a coated substrate. In order to provide a magnetic recording medium capable of high-density recording by using, the present inventors have conducted extensive studies and found that trace amounts of ions (anions and cations) present in coating liquids for film formation, which have not been noticed in the past, Has been found to act as an important factor in forming a coating film having uniform unevenness, and has completed the present invention.

That is, when the present inventor analyzed a conventional coating solution for forming a film, it is usually found that an alkali metal is added to a colloidal solution of an inorganic compound using an organic solvent as a dispersion medium in order to stabilize the colloid. Therefore, about 10 to 30 millimoles / liter of ions such as Na ⁺ ions are contained. In addition, since acids or aqueous ammonia are used in the production of partial hydrolysates such as acetylacetonato chelates, alkoxysilanes, and metal alkoxides, a large amount of ions are present in the liquid containing the film-forming components obtained. is doing. Therefore, the ion concentration of most of the film-forming coating liquids obtained by using as a raw material a liquid containing such an inorganic compound colloidal solution and a film-forming component exceeds 1.0 millimol / liter.

However, when the coating solution for forming a film is produced, the inorganic compound colloidal particles and a partial hydrolyzate obtained from acetylacetonato chelate, alkoxysilane, metal alkoxide, etc. are mixed in an organic solvent. When the ion concentration in the prepared coating liquid for forming a coating is reduced to 1.0 mmol / liter or less, the distribution of the inorganic oxide fine particles contained in the coating formed from this coating liquid becomes uniform, Moreover, almost no traces of agglomerated particles were observed on the surface of this coating, and it was further found that the coating thus obtained had excellent scratch resistance.

The present invention has been completed based on the above findings.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and provides a coating film having uniform unevenness and at the same time excellent durability such as scratch resistance. It is an object of the present invention to provide a coating liquid for forming a film that can be formed on a substrate such as glass, plastic, metal, ceramics, etc., and a method for producing the same.

Another object of the present invention is to provide a film-coated substrate having such a film laminated on a substrate, particularly a film-coated magnetic recording medium.

[0012]

SUMMARY OF THE INVENTION A coating solution for forming a coating film according to the present invention comprises at least one coating film selected from inorganic compound colloidal particles (a) and a partial hydrolyzate of acetylacetonato chelate, alkoxysilane and metal alkoxide. The component (b) and the organic solvent (c) are contained, and the ion concentration in the coating liquid for forming a film is 1.0 mmol / liter or less.

The coating solution for forming a coating film contains a sol containing inorganic compound colloidal particles (a) used as a raw material of the coating solution for forming a coating film and a coating forming component (b) in the process of producing the coating solution for forming a coating film. The cation exchange resin and the anion exchange resin are applied to either the solution or the coating solution for forming a film obtained from these raw materials to adjust the ion concentration in the coating solution for forming a film to 1.0. It can be produced by adjusting the amount to be less than mmol / liter.

Further, the coated substrate according to the present invention is characterized in that the coating formed from the coating solution for forming a coating as described above is laminated on the substrate. In particular, a magnetic recording medium including a disk substrate and a magnetic layer formed thereon and having such a coating between the disk substrate and the magnetic layer or on the magnetic layer is a magnetic disk for high density recording. Alternatively, it is preferable as a magneto-optical disk for high density recording.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The coating liquid for forming a coating film, the method for producing the same and the substrate with a coating film according to the present invention will be specifically described below.

Coating Liquid for Forming a Coating First, the coating liquid for forming a coating according to the present invention will be specifically described. The coating liquid for forming a film according to the present invention comprises inorganic compound colloidal particles (a) and at least one film forming component (b) selected from acetylacetonato chelate, alkoxysilane and a partial hydrolyzate of a metal alkoxide. Are contained in the organic solvent (c).

Specific examples of the inorganic compound colloidal particles (a) used in the coating liquid for forming a film according to the present invention include colloids of inorganic compounds such as silica, titania, zirconia, alumina, iron oxide and tungsten oxide. Examples thereof include particles, colloidal particles of a composite compound composed of two or more kinds of these inorganic compounds, and a mixture of these colloidal particles. Further, the coating liquid for forming a coating film according to the present invention may contain colloidal particles of an inorganic compound other than these.

The inorganic compound colloidal particles used in the present invention have an average particle size of 10 to 300 nm, preferably 10
˜100 nm, the coefficient of variation of particle size is 30% or less,
It is preferably 20% or less, more preferably 10% or less.

The coating solution for forming a film according to the present invention contains at least one film forming component (b) selected from acetylacetonato chelate, alkoxysilane and a partial hydrolyzate of a metal alkoxide. There is.

The partial hydrolyzate of the acetylacetonato chelate used as the component (b) is a chelate compound having acetylacetone as a ligand, and is a condensate of the compound represented by the following chemical formula 1.

[0021]

[Chemical 1]

[Wherein a + b is 2 to 4,
a is 0 to 3, b is 1 to 4, R is -C _n H
_{2n + 1} (n = 3 or 4) and X is —CH ₃ , —OC.
H _3, a -C ₂ H ₅ or -OC ₂ H _5. M ₁ is the periodic table, group IB, group IIA, group B, group IIIA, group B, group IV
Group A, Group B, Group VA, Group B, Group VIA, Group VII Group A, Group VI
It is an element selected from Group II or vanadyl (VO).
Among these, preferable combinations of these elements and the like and a and b are as shown in the following table. ]

[0023]

[Table 1]

Specific examples of such an acetylacetonato chelate include, for example, dibutoxy-bisacetylacetonatozirconium, tributoxy-monoacetylacetonatozirconium, lead bisacetylacetonato, iron trisacetylacetonato, and dibutoxy-bisacetylacetonate. Examples include natohafnium and monoacetylacetonato-tributoxyhafnium.

The partial hydrolyzate of the alkoxysilane used as the component (b) can be obtained from any alkoxysilane exhibiting hydrolyzability. In the present invention, the general formula R ¹ _n Si (OR ² ) _{4 is used. -n} (In the formula, R ¹ and R ² may be the same or different and may be an aryl group, an acryl group, a vinyl group, or a carbon number of 1 to 1.
8 is an alkyl group and a group selected from —C ₂ H ₄ OC _m H _{2m + 1} , where m is an integer of 1 to 4 and n is an integer of 0 to 3). The partially hydrolyzed products obtained are preferred.

Specific examples of the alkoxysilane represented by the above general formula include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraoctylsilane, methyltrimethoxysilane and methyltriethoxysilane. Ethyltriethoxysilane, methyltriisopropoxysilane, dimethyldimethoxysilane, methyltributoxysilane,
Examples include octyltriethoxysilane, phenyltrimethoxysilane and vinyltrimethoxysilane.

Further, a partial hydrolyzate of a metal alkoxide can be used as the component (b). The partial hydrolyzate of the metal alkoxide is M ₂ (OR) _n (wherein
M ₂ is a metal atom, R is an alkyl group or —C _m H _2m
O ₂ ; m is an integer of 3 to 10; n is the same integer as the valence of M ₂ . ) Is a condensate of the compound represented by the formula (1), and one kind or a combination of two or more kinds selected from these condensates can be used. M in the above formula
₂ is not particularly limited as long as it is a metal atom, but preferable M ₂ is Be, Al, Sc, Ti, V, C.
r, Fe, Ni, Zn, Ga, Ge, As, Se, Y,
Zr, Nb, In, Sn, Sb, Te, Hf, Ta,
W, Pb, Bi, Ce or Cu.

Specific examples of such hydrolyzable metal alkoxides include tetrabutoxyzirconium, tetraoctyloxytitanium, and diisopropoxy-dioctyloxytitanium.

Acetylacetonato chelates, partial hydrolysates of alkoxysilanes and metal alkoxides can be prepared by known methods, for example, acetylacetonato chelates which are hydrolyzable to alcohols such as methanol or ethanol.
It is obtained by mixing one or more compounds selected from alkoxysilane and metal alkoxide, and adding water and an acid or aqueous ammonia to this mixed solution. The molecular weight of the partial hydrolyzate used as the component (b) is about 500 to 20,000, preferably 1,000.
It is desirable that the molecular weight is 7,000 (molecular weight in terms of polystyrene) in order to form a thin film having a uniform film thickness.

The compounding ratio of the inorganic compound colloidal particles (a) and the film-forming component (b) contained in the coating solution for forming a film according to the present invention is such that the respective components are expressed in weight% in terms of oxide. That is, the value represented by the following formula {component (a) / [component (a) + component (b)]} × 100 is 0.0005 to 55, preferably 0.
It is preferably in the range of 01 to 25.

Further, in the coating liquid for forming a film according to the present invention, the inorganic compound colloidal particles and the film forming component (b) are used.
An organic solvent (c) that can disperse satisfactorily is used. As such an organic solvent (c), specifically,
Alcohols such as methanol, ethanol, propanol and butanol, ethylene glycol ethers such as methyl cellosolve and ethyl cellosolve, glycols such as ethylene glycol and propylene glycol, esters such as methyl acetate, ethyl acetate and methyl lactate,
Examples thereof include ketones such as acetone and methyl ethyl ketone, and ethers such as butyl ether and tetrahydrofuran.

As described above, the coating liquid for forming a film according to the present invention comprises the inorganic compound colloidal particles (a) and the film forming component (b) in the organic solvent (c), and the solid content concentration is 0.1 to 30% by weight, preferably 0.5 to
It is preferably in the range of 10% by weight.

The ion concentration of the coating solution for forming a film according to the present invention is 1.0 mmol / liter or less, preferably 0.6 mmol / liter or less, and more preferably 0. It is 1 mmol / liter or less.

This ion concentration means the total ion concentration of cations and anions. In the present invention, the cation concentration and anion concentration are measured as follows. Mix 10 ml of the coating solution for film formation with 90 ml of purified distilled water,
After stirring at room temperature for 1 hour, this mixed solution is filtered, and 100 ml of purified distilled water is further passed through the filter material after filtration to collect the filtrate.

The metal ion concentration contained in this recovered filtrate is measured by the atomic absorption method, and the ammonium ion concentration and the anion concentration are measured by the ion chromatography method. When the ion concentration in the coating solution for forming a film measured by such a method exceeds 1.0 mmol / liter, the coating obtained by applying the coating solution for forming a film on the substrate is aggregated. Particle traces and scab-like ridges were observed, and no uniform irregularities were formed on the coating surface.
The cause of such traces of agglomerated particles during the film formation process is that the ions present in the coating solution reduce the surface potential of the inorganic compound colloidal particles, which reduces the repulsion force, and thus the inorganic particles in the coating solution. It is presumed that this is because the compound colloidal particles are likely to aggregate with each other. In addition, the cause of such scab-like ridges during the film formation process is
It is presumed that, as the solvent is removed during the drying process, in addition to the agglomeration of colloidal particles as described above, the film-forming component causes non-uniformity of the film thickness. On the other hand, when the ion concentration in the coating liquid for forming a coating is 1.0 mmol / liter or less, the coating obtained by coating the coating liquid for forming a coating on the substrate as described above contains agglomerated particles. No trace is observed, the film thickness of the film is uniform, and uniform unevenness is formed on the film surface.

Method for Producing Coating Liquid for Forming Coating Hereinafter, the method for producing the coating liquid for forming a film according to the present invention will be specifically described. The coating liquid for forming a coating film according to the present invention is an inorganic compound colloidal particle (a) used as a raw material for the coating liquid for forming a coating film in the process of producing the coating liquid for forming a coating film.
A sol containing sol and a liquid containing the film-forming component (b) and a film-forming coating liquid obtained from these raw materials are treated with a cation exchange resin and an anion exchange resin to form a film. It can be produced by adjusting the ion concentration in the forming coating liquid to 1.0 mmol / liter or less.

The method for producing the coating solution for forming a coating film according to the present invention will be specifically described as follows. The coating liquid for forming a coating film according to the present invention is produced, for example, by the following method.

First, a dispersion liquid of inorganic compound colloidal particles having an alcoholic organic solvent as a dispersion medium is alternately treated with a cation exchange resin and an anion exchange resin, and the cations and the cations existing in the dispersion medium of the dispersion liquid are treated. Dispersion of inorganic compound colloidal particles using a desired organic solvent as a dispersion medium by removing anions and, if necessary, mixing or substituting with an organic solvent other than an alcoholic solvent having an ion concentration of 1.0 mmol / liter or less. Get the liquid.

Next, one or more hydrolyzable compounds selected from acetylacetonato chelate, alkoxysilane and metal alkoxide are dissolved in an organic solvent,
When water and an acid are added to react with each other or ammonia water is added to react with each other to obtain a partial hydrolyzate having a desired molecular weight, a liquid containing the partial hydrolyzate is treated with a cation exchange resin and an anion. Treat with ion exchange resin.

The dispersion liquid of the inorganic compound colloidal particles obtained through the above steps is mixed with a liquid containing a partial hydrolyzate. The coating liquid for forming a coating film according to the present invention can also be produced by the following method.

A dispersion liquid of inorganic compound colloidal particles using an organic solvent as a dispersion medium is mixed with an untreated liquid containing the partial hydrolyzate obtained as described above, or a dispersion liquid of inorganic compound colloidal particles. And partially hydrolyzing the hydrolyzable compound after mixing with the hydrolyzable compound,
The resulting mixture is treated with a cation exchange resin and an anion exchange resin. In the treatment of this mixed solution, a cation exchange resin and an anion exchange resin may be used alternately, or a mixed resin of a cation exchange resin and an anion exchange resin may be used.

Coated Substrate The coated substrate according to the present invention will be specifically described below. In the coated substrate according to the present invention, a coating formed from the coating liquid for coating as described above is laminated on the substrate.

As the substrate of such a coated substrate, a flat plate, a three-dimensional object, a film or the like made of glass, plastic, metal, ceramic or the like can be appropriately used depending on the use of the coated substrate. ..

In particular, it includes a disk substrate and a magnetic layer formed on the disk substrate, and between the disk substrate and the magnetic layer and / or
Alternatively, a magnetic recording medium having such a coating on the magnetic layer is used as a high density recording magnetic disk or a high density recording magneto-optical disk.

The coated substrate according to the present invention is formed by dipping the coating liquid according to the present invention according to the shape of the substrate directly or after forming a magnetic layer or the like on the substrate. Coating by a method such as a spinner method, a spray method, a roll coater method, or flexographic printing, followed by drying at room temperature to 90 ° C. and further curing by heating at 200 ° C. or higher, preferably 300 ° C. or higher. Is obtained. Further, if necessary, after the coating step or the drying step, or during the drying step, the coating in the uncured stage is irradiated with an electromagnetic wave having a wavelength shorter than visible light, or the coating in the uncured stage is accelerated in curing reaction. By exposing to a gas atmosphere for curing, hardening of the obtained coating film is promoted and the coating film hardness is increased. The same effect can be obtained by performing this gas treatment after heat curing.

The electromagnetic waves with which the coating film in the uncured stage before heating is irradiated are specifically ultraviolet rays, electron beams, X rays.
Rays and γ rays are exemplified, but ultraviolet rays are preferable. For example, a high pressure mercury lamp having a maximum emission intensity of about 250 nm and 360 nm and a light intensity of 10 mW / cm ² or more is used as an ultraviolet ray source, and 100 mJ / cm 2
² or more, preferably by irradiation with ultraviolet rays of 1000 mJ / cm ² or more energy in the coating of the uncured stage, the curing reaction of the uncured stage coating is promoted.

Examples of the gas that accelerates the curing reaction of the coating film in the uncured stage before heating include ammonia and ozone. Further, the acceleration of the curing of the coating film in such a gas atmosphere is performed when the coating film in the uncured stage has a gas concentration of 1
00-100,000 ppm, preferably 1000-1
It can be achieved by treating for 1 to 60 minutes under the above-mentioned active gas atmosphere such that the concentration is 10,000 ppm.

In the coated substrate according to the present invention, another coating is further formed on the coating thus formed, if necessary. For example, a coating liquid for forming a coating film according to the present invention may be applied to a disk substrate and dried to form a coating film, and a magnetic layer may be formed on the obtained coating film. A recording medium is manufactured.

[0049]

EFFECT OF THE INVENTION According to the coating solution for forming a coating film of the present invention, it has uniform unevenness, almost no traces of aggregated particles are observed on the surface, it has excellent durability such as scratch resistance, and light reflection. A coating film having excellent prevention performance can be formed on a substrate.

Further, according to the method for producing the coating liquid for forming a coating film of the present invention, a coating liquid for forming a coating film capable of forming a coating film having such excellent properties can be easily and reliably produced.

The film-coated substrate according to the present invention has a film having the above-mentioned excellent properties formed on the substrate, and is used for magnetic recording media such as magnetic disks and magneto-optical disks, and display panels for display devices. It is suitable as a camera lens. A magnetic disk provided with such a coating on its surface,
In a magnetic recording medium such as a magneto-optical disk, since uniform unevenness is formed on this coating, the coefficient of static friction when the magnetic head slides on the magnetic recording medium in the recording device or the reproducing device is small, and The flying height can be maintained at a small value without damaging the magnetic head.

[0052]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0053]

Example 1 Commercially available organosilica sol having an ion concentration of 20 mmol / liter [manufactured by Catalysts & Chemicals Industry Co., Ltd., trade name "Oscar"; average particle size 45 nm, particle size variation coefficient 9.0%, concentration 10 wt. %, Solvent isopropanol]
Cation exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion SK-1B"] and anion exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion SA-2"
0 "] for 10 times to remove ions in the colloidal solution. Then, the solvent of the colloidal solution was replaced with hexylene glycol by a heating vacuum distillation method to obtain a silica colloidal dispersion having a concentration of 5% by weight.

On the other hand, tetraethoxysilane [manufactured by Tama Chemical Industry Co., Ltd., trade name "ethyl silicate 40"; SiO
40% by weight in terms of ₂ ] 198 g, concentrated nitric acid 0.8 g, hexylene glycol 2020 g, and ion-exchanged water 63.
After mixing 7 g, 990 g of an isopropanol solution of tetraoctyloxytitanium (10% by weight in terms of TiO ₂ ) and a butanol solution of tributoxy-monoacetylacenatozirconium (10% in terms of ZrO _2).
Wt%) 198 g, and stirred at room temperature for 48 hours,
Partial hydrolyzate (molecular weight 4500 in terms of polystyrene)
Got

This partial hydrolyzate was mixed with 80.8 g of the above silica colloid dispersion, and to this mixture were further mixed 2380 g of isopropanol, 2380 g of butanol and 2380 g of hexylene glycol to give a solid content of 1.9 wt. %, And the ratio of silica colloid particles in the total solid content was 2.0% by weight to obtain a coating liquid for forming a film.

The total ion concentration contained in this coating solution for forming a film was measured by the above-mentioned method and was found to be 0.9 mmol / liter. Then, this coating solution for forming a coating film was applied on a soda lime glass disk substrate having an outer diameter of 95 mm, an inner diameter of 25 mm, a thickness of 1.20 mm and a surface average roughness of 50 Å by a spin coater and dried at 80 ° C. By irradiating with ultraviolet rays of 400 mJ and further baking at a temperature of 300 ° C. for 1 hour, a coated substrate having a film flat portion with a film thickness of 270 Å was obtained.

The coating characteristics of this coated substrate were measured and evaluated as follows, and the results shown in Table 2 were obtained. A. Aggregation state of particles: An electron micrograph of the surface of the coating film was taken, and from the obtained photograph, the aggregation state of particles observed on the surface of the coating film was divided into the following four stages and displayed.

A: Almost no trace of aggregated particles is observed, and the distribution of particles is uniform. ◯: There are few traces of aggregated particles observed, and the distribution of particles is uniform. Δ: Some traces of aggregated particles are observed, but traces of three or more aggregated particles are few, and the distribution of particles is uniform.

X: Many traces of agglomerated particles are observed, and the distribution of particles is non-uniform. B. Average convex portion interval: The distance between adjacent convex portions in an electron micrograph was measured with a caliper, and the average value (d) and standard deviation (σ) were obtained. The number of measurements is 100. C. Hardness of coating: Pencil hardness was evaluated according to JIS D 0212-88. D. Scratch resistance of coating: Office eraser (LION N
o. 50-50) was placed on the coating and was slid 300 times with a load of 2 kg. The peeled state of the coating was observed visually and with an optical microscope. E. Static friction coefficient: Measured according to JIS K 7125.

Then, the coated substrate of Example 1 was subjected to DC magnetron sputtering to form Cr having a thickness of 1500 angstroms.
Base film made of Co and 700 Å thick Co
A magnetic film made of Ni and a protective film made of carbon having a thickness of 300 Å were laminated. Further, a lubricant made of perfluoropolyether was applied on the protective film with a spin coater to a thickness of 30 Å to obtain a magnetic disk of Example 1.

The characteristics of the magnetic disk were evaluated by obtaining the surface roughness [average surface unevenness difference; measured by a tunnel microscope] and the initial coefficient of static friction. The results are also shown in Table 2.

[0062]

Example 2 In the same manner as in Example 1, a commercially available organosilica sol [manufactured by Catalysts & Chemicals Industry Co., Ltd., trade name "Oscar"; average particle size 45 nm, particle size variation coefficient 9.0%, concentration 10 wt. %, Solvent isopropanol], cation exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion SK-1B"] and anion exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion SA" -20 "] to remove the ions in the colloidal solution 10 times each, and then replace the solvent of the colloidal solution with hexylene glycol by the heating vacuum distillation method to obtain a silica colloidal dispersion having a concentration of 5% by weight. Got

On the other hand, tetraethoxysilane [manufactured by Tama Chemical Industry Co., Ltd., trade name "ethyl silicate 40"; SiO
40% by weight in terms of ₂ ] 198 g, concentrated nitric acid 0.8 g, hexylene glycol 2020 g, and ion-exchanged water 63.
After mixing 7 g, 990 g of an isopropanol solution of tetraoctyloxytitanium (10% by weight in terms of TiO ₂ ) and a butanol solution of tributoxy-monoacetylacenatozirconium (10% in terms of ZrO _2).
Wt%) 198 g, and stirred at room temperature for 48 hours,
Partial hydrolyzate (molecular weight 4500 in terms of polystyrene)
Got

This partial hydrolyzate was immediately converted into a cation exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion S"].
K-1B ”] and anion exchange resin [Mitsubishi Kasei Co., Ltd.]
Ion removal was carried out by passing each twice through the product, trade name "Diaion SA-20".

The partially hydrolyzed product from which the ions had been removed was mixed with 80.8 g of the above silica colloidal dispersion, and 2380 g of isopropanol and 2 parts of butanol were added to this mixture.
380 g and 2380 g of hexylene glycol were further mixed to obtain a coating solution for forming a film having a solid content concentration of 1.9% by weight and a ratio of silica colloid particles in the total solid content of 2.0% by weight.

Ion concentration of the coating solution for forming the coating, coating characteristics of the coated substrate obtained in the same manner as in Example 1 using this coating solution, and obtained from this substrate in the same manner as in Example 1 The characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0068]

EXAMPLE 3 Commercially available organosilica sol [Catalyst Kasei Kogyo KK, trade name "Oscar"; average particle size 45 nm, particle size variation coefficient 9.0%, concentration 10% by weight, solvent isopropanol] was used as colloidal particles. In order to elute the cations in the solution, a heat treatment was performed at 150 ° C. for 2 hours using an autoclave, and then a cation exchange resin [trade name “DIAION SK-1B” manufactured by Mitsubishi Kasei Co., Ltd.]. And anion exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion SA-20"] 10 times each to remove ions, and then the solvent is heated to hexylene glycol by heating under reduced pressure. Substitution was performed to obtain a silica colloidal dispersion having a concentration of 5% by weight.

On the other hand, tetraethoxysilane [manufactured by Tama Chemical Industry Co., Ltd., trade name "ethyl silicate 40"; SiO
40% by weight in terms of ₂ ] 198 g, concentrated nitric acid 0.8 g, hexylene glycol 2020 g, and ion-exchanged water 63.
After mixing 7 g, 990 g of an isopropanol solution of tetraoctyloxytitanium (10% by weight in terms of TiO ₂ ) and a butanol solution of tributoxy-monoacetylacenatozirconium (10% in terms of ZrO _2).
Wt%) 198 g, and stirred at room temperature for 48 hours,
Partial hydrolyzate (molecular weight 4500 in terms of polystyrene)
Got

This partial hydrolyzate was immediately converted to a cation exchange resin [Mitsubishi Kasei Kogyo KK, trade name "Diaion S"
K-1B ”] and anion exchange resin [Mitsubishi Kasei Co., Ltd.]
Ion removal was carried out by passing each twice through the product, trade name "Diaion SA-20".

The partially hydrolyzed product from which the ions had been removed was mixed with 80.8 g of the above silica colloid dispersion, and 2380 g of isopropanol and 2 parts of butanol were added to this mixture.
380 g and 2380 g of hexylene glycol were further mixed to obtain a coating solution for forming a film having a solid content concentration of 1.9% by weight and a ratio of silica colloid particles in the total solid content of 2.0% by weight.

Ion concentration of the coating solution for forming a coating, coating characteristics of a coated substrate obtained in the same manner as in Example 1 using this coating solution, and obtained from this substrate in the same manner as in Example 1 The characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0074]

[Example 4] The coating solution for forming a film obtained in Example 3 was further added with a cation exchange resin [trade name "Diaion SK-1B" manufactured by Mitsubishi Kasei Kogyo Co., Ltd.] and an anion exchange resin [Mitsubishi Kasei]. Product name "Diaion SA-2" manufactured by Kogyo Co., Ltd.
0 "] to remove ions until the concentration of ions in the coating solution for forming a coating reaches 0.05 mmol / liter to obtain a coating solution for forming a coating of Example 4. The solid content concentration of the coating liquid for forming a film of Example 4 was 1.9% by weight, and the ratio of the silica colloid particles in the total solid content was 2.0% by weight.

Ion concentration of the coating solution for forming the coating, coating characteristics of the coated substrate obtained in the same manner as in Example 1 using this coating solution, and obtained from this substrate in the same manner as in Example 1 The characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0077]

Example 5 Commercially available titania sol [Catalyst Kasei Kogyo Co., Ltd.]
Product name “Neo Sunveil”; average particle size 15 nm, particle size variation coefficient 19.0%, concentration 10% by weight, solvent isopropanol] cation exchange resin [Mitsubishi Kasei Kogyo Co., Ltd.]
Manufactured by the trade name "Diaion SK-1B"] and anion exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion SA-20"] 10 times each to remove ions, The solvent was replaced with hexylene glycol by a heating vacuum distillation method to obtain a titania colloidal dispersion having a concentration of 5% by weight.

On the other hand, tetraethoxysilane [manufactured by Tama Chemical Industry Co., Ltd., trade name "ethyl silicate 28"; SiO
28% by weight in terms of ₂ ] 31 g, 0.5 g of concentrated nitric acid, 203 g of hexylene glycol and 10 g of ion-exchanged water, and then mixed with butanol solution of dibutoxy-bisacetylacetonatotitanium (10% by weight in terms of TiO ₂ ).
12 g was mixed and stirred at room temperature for 12 hours to obtain a partial hydrolyzate (molecular weight 3000 in terms of polystyrene).

This partial hydrolyzate was immediately converted into a cation exchange resin [Mitsubishi Kasei Kogyo KK, trade name "Diaion S".
K-1B ”] and anion exchange resin [Mitsubishi Kasei Co., Ltd.]
Manufactured by trade name "DIAION SA-20"], and each ion was removed three times.

This partial hydrolyzate was mixed with 0.2 g of the above titania colloidal dispersion, 385 g of isopropanol, 385 g of butanol and 385 g of hexylene glycol were mixed with this mixture, and the ions were removed with the ion exchange resin. A coating solution for forming a film having a solid content of 0.7% by weight and a proportion of titania colloid in the total solid content of 0.1% by weight was obtained.

Ion concentration of the coating solution for forming a coating, coating characteristics of a coated substrate obtained in the same manner as in Example 1 using this coating solution, and obtained from this substrate in the same manner as in Example 1 The characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0083]

Example 6 A commercially available organosilica sol [Catalyst Kasei Kogyo KK, trade name "Oscar"; average particle size 25 nm, particle size variation coefficient 9.5%, concentration 10% by weight, solvent isopropanol] Ion exchange resin [Mitsubishi Chemical Industries, Ltd.]
Manufactured by the trade name "Diaion SK-1B"] and anion exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion SA-20"] 10 times each to remove ions, The solvent was replaced with propylene glycol by a heating vacuum distillation method to obtain a silica colloidal dispersion having a concentration of 5% by weight.

On the other hand, tetramethoxysilane [manufactured by Tama Chemical Industry Co., Ltd., trade name "methyl silicate 51"; SiO
51% by weight in terms of ₂ ] 27.6 g, monomethyltrimethoxysilane (40% by weight in terms of SiO ₂ ) 19.5 g,
After mixing 0.5 g of concentrated nitric acid, 730 g of propylene glycol and 28 g of ion-exchanged water, dibutoxy-
779 g of a butanol solution of bisacetylacenatozirconium (10% by weight in terms of ZrO ₂ ) was mixed and stirred at room temperature for 24 hours to obtain a partial hydrolyzate (molecular weight in terms of polystyrene of 4000).

This partial hydrolyzate was immediately converted to a cation exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion S"].
K-1B ”] and anion exchange resin [Mitsubishi Kasei Co., Ltd.]
Manufactured by trade name "DIAION SA-20"], and each ion was removed three times.

The ion-removed partial hydrolyzate was mixed with 4.0 g of the silica colloidal dispersion, and 2650 g of isopropanol and 26 of butanol were added to the mixture.
50 g and 3111 g of propylene glycol were further mixed to obtain a coating liquid for forming a film having a solid content concentration of 1.0% by weight and a ratio of silica colloid particles in the total solid content of 0.2% by weight.

Ion concentration of the coating solution for forming the film, using this coating solution, outer diameter 95 mm, inner diameter 25 mm, thickness 1.
Coating properties of a coated substrate obtained by coating in the same manner as in Example 1 on an aluminum disc substrate having a surface average roughness of 20 Å and a surface roughness of 80 Å, and obtained from this substrate in the same manner as in Example 1. The characteristics of the magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0089]

[Example 7] A commercially available organosilica sol [Catalyst Chemical Co., Ltd., trade name "Oscar"; average particle size 80 nm, particle size variation coefficient 10.0%, concentration 5% by weight, solvent ethanol] was used as a cation. Exchange resin [Mitsubishi Kasei Industry Co., Ltd., trade name "Diaion SK-1B"] and anion exchange resin [Mitsubishi Kasei Co., Ltd., trade name "Diaion SA-"
20 "] to remove ions to obtain a silica colloidal dispersion having a concentration of 5% by weight.

On the other hand, dibutoxy-bisacetylacenatozirconium butanol solution (10% by weight in terms of ZrO ₂ ) 990 g, concentrated nitric acid 0.2 g, ion-exchanged water 128
After mixing g, the mixture was stirred at room temperature for 12 hours to obtain a partial hydrolyzate (molecular weight 3000 in terms of polystyrene).

This partial hydrolyzate was immediately converted to a cation exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion S
K-1B ”] and anion exchange resin [Mitsubishi Kasei Co., Ltd.]
Manufactured by trade name "DIAION SA-20"], and each ion was removed three times.

This partial hydrolyzate was mixed with 20.0 g of the above silica colloidal dispersion, and the solid content concentration was 3.0% by weight, and the ratio of silica colloidal particles in the total solid content was 1.0% by weight. A coating liquid for forming a film was obtained.

Ion concentration of the coating solution for forming a coating, coating characteristics of a coated substrate obtained in the same manner as in Example 1 using this coating solution, and obtained from this substrate in the same manner as in Example 1 The characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0095]

Example 8 Commercially available organosilica sol [Catalyst Chemical Co., Ltd., trade name "Oscar"; average particle size 100 nm,
The variation coefficient of particle size is 9.8%, the concentration is 10% by weight, and the solvent is isopropanol. Cation exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion SK-1B"] and anion exchange resin [Mitsubishi Chemical industry Co., Ltd., trade name "Diaion SA-20"] each 10 times, after removing the ions, the solvent was replaced by propylene glycol by heating under reduced pressure distillation method, the concentration of 5% by weight. A silica colloidal dispersion of was obtained.

On the other hand, tetraethoxysilane [manufactured by Tama Chemical Industry Co., Ltd., trade name "ethyl silicate 28"; SiO
₂ in terms of 28 wt%) 714.3g, acetate 2g, after mixing the propylene glycol 2554g of ion-exchanged water 60 g, and stirred for 5 hours at 40 ° C., to obtain partial hydrolyzate (molecular weight 5000 in terms of polystyrene) ..

This partial hydrolyzate was immediately converted into a cation exchange resin [Mitsubishi Kasei Kogyo Co., Ltd., trade name "Diaion S"].
K-1B ”] and anion exchange resin [Mitsubishi Kasei Co., Ltd.]
Manufactured by trade name "DIAION SA-20"], and each ion was removed three times.

This partial hydrolyzate was mixed with 83.4 g of the above silica colloidal dispersion, and 670 g of hexylene glycol was further mixed with this mixture to give a solid content of 5.
A coating liquid for forming a film was obtained in which the content of silica colloid particles in the total solid content was 0% by weight and 0.4% by weight.

Ion concentration of the coating solution for forming a coating, coating characteristics of a coated substrate obtained in the same manner as in Example 1 using this coating solution, and obtained from this substrate in the same manner as in Example 1 The characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0101]

[Embodiment 9] Outer diameter 95 mm, inner diameter 25 mm, thickness 1.20 m
m, a surface film of soda lime glass having an average surface roughness of 50 angstrom, a 1500 angstrom-thick Cr undercoat film and a 700 angstrom-thick CoNi magnetic film were sequentially laminated by DC magnetron sputtering to obtain a film. The coating solution for forming a film of Example 4 was applied onto the obtained laminated film by a spin coater, dried at 80 ° C., and then irradiated with ultraviolet rays of 4000 mJ, and further 30
By baking at a temperature of 0 ° C. for 1 hour, a film-coated substrate having a film flat portion with a film thickness of 300 Å was obtained.

Then, a lubricant made of perfluoropolyether was further coated on the coating of the coated substrate with a spin coater to a thickness of 30 Å to obtain a magnetic disk. The coating characteristics of the obtained coated substrate and the characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0104]

Example 10 Commercially available organosilica sol [Catalyst Kasei Kogyo KK, trade name "Oscar"; average particle size 45 nm,
Particle size variation coefficient 9.5%, concentration 10% by weight, solvent isopropanol] The solvent was replaced with hexylene glycol by heating under reduced pressure distillation method, and the concentration of the silica colloid was 5% by weight without ion removal treatment. A liquid was obtained.

On the other hand, tetraethoxysilane [manufactured by Tama Chemical Industry Co., Ltd., trade name "ethyl silicate 40"; SiO
40% by weight in terms of ₂ ] 198 g, concentrated nitric acid 0.8 g, hexylene glycol 2020 g, and ion-exchanged water 63.
After mixing 7 g, 990 g of an isopropanol solution of tetraoctyloxytitanium (10% by weight in terms of TiO ₂ ) and a butanol solution of tributoxy-monoacetylacenatozirconium (10% in terms of ZrO _2).
Wt%) 198 g, and stirred at room temperature for 48 hours,
Partial hydrolyzate (molecular weight 4500 in terms of polystyrene)
Got

This partial hydrolyzate was mixed with 80.8 g of the above silica colloid dispersion, and 2380 g of isopropynol, 2380 g of butanol and 2380 g of hexylene glycol were mixed with this mixture to give a solid content of 1.9% by weight. A coating liquid for forming a film was obtained in which the ratio of silica colloidal particles in the total solid content was 2.0% by weight.

This coating solution for forming a film was used as a cation exchange resin [manufactured by Mitsubishi Kasei Kogyo Co., Ltd. under the trade name "Diaion SK".
-1B ”] and anion exchange resin [Mitsubishi Kasei Co., Ltd.]
Co., Ltd., trade name “Diaion SA-20”] and passed 20 times each to adjust the ion concentration in the coating solution for film formation to 0.
It was set to 2 mmol / liter.

The ion concentration of the coating solution for forming a coating film thus obtained, the coating characteristics of the coated substrate obtained in the same manner as in Example 1 using this coating solution, and the examples from this substrate The characteristics of the magnetic disk obtained in the same manner as in Example 1 were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2. An electron micrograph of the surface of the coated substrate is shown in FIG.

[0110]

Comparative Example 1 The ion concentration of the coating liquid for forming a film before the treatment with the cation exchange resin and the treatment with the anion exchange resin in Example 10 was 2.0 mmol / liter.

Ion concentration of the coating solution for forming a coating, coating characteristics of a coated substrate obtained in the same manner as in Example 1 using this coating solution, and obtained from this substrate in the same manner as in Example 1 The characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2. An electron micrograph of the surface of the coated substrate is shown in FIG.

[0113]

Comparative Example 2 A solvent of commercially available organosilica sol [Catalyst Chemical Co., Ltd., trade name "Oscar"; average particle diameter 45 nm, particle diameter variation coefficient 9.5%, concentration 10% by weight, solvent isopropanol] was used. Hexylene glycol was subjected to solvent substitution by a heating vacuum distillation method to obtain a silica colloidal dispersion liquid having a concentration of 5% by weight, which was not subjected to ion removal treatment.

On the other hand, tetraethoxysilane [manufactured by Tama Chemical Industry Co., Ltd., trade name "ethyl silicate 40"; SiO
40% by weight in terms of ₂ ] 198 g, concentrated nitric acid 2.4 g, hexylene glycol 1846.9 g, and ion-exchanged water 6
After mixing 3.7 g, an isopropanol solution of tetraoctyloxytitanium (10 in terms of TiO ₂₎ was added to this.
% By weight) and 198 g of a butanol solution of tributoxy-monoacetylacenatozirconium (10% by weight in terms of ZrO ₂ ) are mixed and stirred at room temperature for 48 hours to partially hydrolyze (molecular weight in terms of polystyrene: 500).
0) was obtained.

This partial hydrolyzate was mixed with 252.2 g of the above silica colloid dispersion, and 2380 g of isopropanol, 2380 g of butanol and 2380 g of hexylene glycol were mixed with this mixture to give a solid content of 2.
A coating liquid for forming a film was obtained in which the proportion of the inorganic compound colloidal particles in the total solid content was 0% by weight and 6.0% by weight.

Ion concentration of the coating solution for forming a coating, coating characteristics of a coated substrate obtained in the same manner as in Example 1 using this coating solution, and obtained from this substrate in the same manner as in Example 1 The characteristics of the obtained magnetic disk were measured and evaluated in the same manner as in Example 1.

The results are also shown in Table 2.

[0118]

[Table 2]

[Brief description of drawings]

FIG. 1 is an electron micrograph showing a coating surface state of a coated magnetic disk according to the present invention.

FIG. 2 is an electron micrograph showing a coating surface state of a coated magnetic disk of a comparative example.

Claims (4)

[Claims] 1. An inorganic compound colloidal particle (a) and at least one film-forming component (b) selected from an acetylacetonato chelate, an alkoxysilane and a partial hydrolyzate of a metal alkoxide, and an organic solvent (c). ), And the ion concentration of the coating liquid for forming a coating film is 1.0 mmol / liter or less. 2. In the process of producing a coating liquid for forming a film, a sol containing at least the inorganic compound colloidal particles (a), a liquid containing the component (b) for forming a film, and a coating liquid for forming a film, The coating according to claim 1, wherein the treatment with an ion exchange resin and the treatment with an anion exchange resin are carried out so that the ion concentration in the coating liquid for film formation obtained is 1.0 mmol / liter or less. Method for producing coating liquid for forming. 3. A substrate with a coating, wherein a coating formed from the coating liquid for forming a coating according to claim 1 is laminated on the substrate. 4. A coating solution for forming a coating film according to claim 1, comprising a disk substrate and a magnetic layer formed thereon, and between the disk substrate and the magnetic layer and / or on the magnetic layer. A magnetic recording medium having a coating formed from.