JPH04356723A - Flexible magnetic disk - Google Patents

Abstract

PURPOSE:To provide the disk imparted with excellent magnetic recording characteristics by uniformizing the dispersion of the magnetic powder of a magnetic coating material to improve dispersion stability and to smooth the plane of a coating film. CONSTITUTION:The magnetic coating material for the flexible magnetic disk constituted by providing the coating film of the magnetic coating material contg. the magnetic powder on a nonmagnetic base consists of polyisocyanate having average 2.5 to 6 pieces of isocyanate groups, an additive compd. having reactivity with this isocyanate group and a resin having sulfonate.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to flexible magnetic disks, and more specifically, it improves the dispersibility and dispersion stability of ferromagnetic powder in magnetic coatings, improves the surface smoothness of magnetic coatings, and provides excellent The present invention relates to a flexible magnetic disk with magnetic recording properties, particularly high-density magnetic recording properties.

0002

[Prior Art] In recent years, high-density recording on flexible magnetic disks has been studied, and as ferromagnetic powder, fine particle size Co-coated γ has been studied.
- Iron oxide, metal magnetic powder with small particle size and high coercivity, hexagonal ferrite powder with hexagonal plate shape and small particle size, etc. are attracting attention. However, when making paints from these ferromagnetic powders, the quality of dispersion is always a problem, and a satisfactory solution has not yet been reached.

For example, since hexagonal ferrite powder has an axis of easy magnetization in the direction perpendicular to the plate surface, ferrite particles in the paint come into contact with each other plate-like surfaces, forming extremely strong aggregates. Further, since metal magnetic powder has a larger magnetic moment than oxide-based magnetic powder, the powders strongly attract each other and form extremely strong aggregates in the paint.

[0004] Binders for magnetic powder include vinyl chloride-vinyl acetate polymers, cellulose resins, polyurethane resins, polyester resins, polyester-polyurethane resins, polycarbonates, polyurethane resins, polyvinyl butyral resins, etc. Various types of polymers are known, and in recent years, particularly from the viewpoint of dispersibility and filling properties of magnetic powder, polar groups such as sulfonic acid groups, sulfuric acid ester groups, phosphoric acid ester groups, phosphonic acid groups, and carboxylic acid groups have been added to the above polymers. Backbone or side chain attached resins are becoming widely used. However, since the cohesive force of the metal magnetic powder and hexagonal ferrite powder is extremely strong, it is difficult to finely disperse the aggregates with the binder, and only paints with insufficient dispersibility can be obtained. Can't get the disc.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the dispersibility and dispersion stability of ferromagnetic powder in a magnetic coating, thereby achieving even higher surface smoothness and higher density of the magnetic coating.
The object of the present invention is to provide a flexible magnetic disk having excellent magnetic recording properties, particularly high-density magnetic recording properties.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted extensive research and found that an average of 2
．． When a magnetic paint contains an addition compound derived from a polyisocyanate having 5 to 6 isocyanate groups and a compound reactive with the isocyanate groups, the above-mentioned agglomeration of the ferromagnetic powder is loosened during the dispersion treatment of the magnetic powder. Furthermore, the loosened magnetic powder is prevented from re-agglomerating in the paint (
For example, even if the paint is left to stand for a long time and then formed into a film, there are almost no "bumps" due to re-agglomeration), so the magnetic layer (
The present invention was achieved based on the discovery that the surface smoothness of a magnetic coating film can be significantly improved.

That is, the present invention provides a flexible magnetic disk comprising a coating of magnetic paint containing ferromagnetic powder on a non-magnetic support, wherein the magnetic paint has an average of 2.5
A polyisocyanate having ~6 isocyanate groups, an addition compound (A) derived from a compound reactive with the isocyanate groups, and a resin (B) having a sulfonate.
) is a flexible magnetic disk characterized by including:

The present invention will be explained.

In the present invention, the nonmagnetic support is not particularly limited, and any commonly used nonmagnetic support can be used. Examples of materials forming the non-magnetic support include various synthetic resins such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene, polypropylene, polycarbonate, polyamide, polyamideimide, polyimide, polysulfone, and polyethersulfone. Examples include films and metal foils such as aluminum foil and stainless steel foil.

In the present invention, the ferromagnetic powder is not limited and any commonly used ferromagnetic powder can be used.
O-adhered gamma ferrite powder, metal powder mainly composed of Fe, hexagonal barium ferrite powder, etc. are preferable. Furthermore, this Co-adhered gamma ferrite powder has a saturation magnetization greater than 70 emu/g and a specific surface area of 20 m2/g.
Larger, with coercive force of 500 Oe (Oersted)
Larger ones are preferred. In addition, this Fe-based metal powder has a saturation magnetization greater than 100 emu/g, a specific surface area greater than 30 m2/g, and a coercive force of 70 emu/g.
Preferably, it is in the range of 0 to 2000 Oe. In addition, this hexagonal barium ferrite powder has a saturation magnetization greater than 50 emu/g and a specific surface area of 25 m2/g.
It is preferable to have a larger coercive force in the range of 200 to 2000 Oe.

[0011] In the present invention, the magnetic paint is prepared by mixing and dispersing such ferromagnetic powder with a binder, etc. As a dispersion method, a known method or a method accumulated in the art can be used. .

In the present invention, one component of the binder is the addition compound (A), that is, an average of 2
．． It is characterized by using a polyisocyanate having 5 to 6 isocyanate groups and an addition compound derived from a compound reactive with the isocyanate groups.

[0013] Examples of this polyisocyanate include:

[0014]

[Chemical formula 1]

[0015]

[Case 2]

[0016]

[Chemical formula 3]

[0017]

[C4]

[0018]

[C5]

[0019]

[C6]

[0020]

[C7]

[0021]

[Image Omitted] [Image Omitted] These exemplified compounds have an isocyanuric acid structure obtained from a diisocyanate by a biuret reaction, or purified by ring formation of a diisocyanate.

The compound to be reacted with this polyisocyanate is a group reactive with NCO groups (for example, -OH, -NH
2, -NHR (R; alkyl group having 1 to 4 carbon atoms), etc.)
It is a compound having 1 to 3 carbon atoms, for example, 8 to 30 carbon atoms.
aliphatic or alicyclic monoalcohol (hydrogen atoms may be partially substituted with halogen atoms or aryl groups), at least one -O- group and/or -COO- group in the molecule aliphatic, alicyclic or aromatic monoalcohols (hydrogen atoms may be partially substituted with halogen atoms), fatty acids having 2 to 3 of the above reactive groups and a molecular weight of 3000 or less group, alicyclic or aromatic compound (-O-, -COO-, -CONH-
group, -S- group, -SO2- group, etc.)
, a compound having a Tzelevitinoff active hydrogen atom and at least one nitrogen atom-containing basic group.

The addition compound (A) used in the present invention is
For example, Japanese Patent Publication No. 2-19844, Japanese Patent Application Publication No. 1-135
526, Japanese Patent Application Laid-Open No. 1-139132, etc., together with the manufacturing method thereof.

This addition compound (A) has a strong affinity for the surface of the ferromagnetic powder due to the -NCO- group component locally localized in the molecule, which significantly reduces the dispersion of the ferromagnetic powder in the magnetic paint. In addition, a large number of side chain groups extending radially from the polyisocyanate skeleton have the effect of preventing re-agglomeration of the ferromagnetic powder once dispersed.

The amount of the additional compound to be used is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 25 parts by weight, particularly 1 to 25 parts by weight, per 100 parts by weight of the ferromagnetic powder. If this amount is too small, this effect will not be expressed. On the other hand, if this amount is too large, there will be no room for adding other types of additives.

In the present invention, a resin (B) having a sulfonate salt is used in combination with the addition compound (A). Thereby, the effects of the additional compound (A) can be further enhanced.

The resin (B) having a sulfonate may be any resin as long as it has a sulfonate in its molecule. Examples of such resins include urethane resins, polyester resins, vinyl chloride resins, etc. Examples include polymers, vinylidene chloride copolymers, acrylic resins, butadiene-acrylonitrile polymers, styrene-butadiene copolymers, and the like.

Such a polar group-introduced binder may be commercially available, and can be produced, if desired, according to techniques in known literature or with some modifications. To cite some examples of these, production of polyester binders: JP-A-54-143117, JP-A-54-15141;
No. 7, No. 54-157603, No. 56-74827, No. 59-132418, No. 59-172118,
60-55514, JP 1-95126, Production of polyurethane binder: JP 57-92423,
No. 58-41436, No. 61-202327, No. 6
No. 2-28927, No. 62-66420, JP-A-1-
No. 115920, production of polyurethane and polyurea binders: JP 62-28920, production of vinyl polymerization binders: JP 58-108032, JP 60-121
No. 514, No. 61-32216, No. 61-39927
No. 62-208419, Production of Betaine (Other) Binders: JP-A-60-177427, and so on.

The binder used in the present invention is -SO3 M (
M needs to be a polymer containing at least one of alkali metal ions and/or quaternary ammonium ions.

Examples of the above-mentioned polymers having polar groups include polyurethane resins, polyester urethane resins, vinyl chloride copolymers, and polyester resins. Such resins may be used alone or in combination of two or more.

The content of the polar group in the polymer is at least 1
x10-6 equivalent/g (resin) or more is preferable, and more preferably 1 x 10-6 to 1 x 10-2 equivalent/g (resin) from the viewpoint of dispersing the magnetic powder and preventing reagglomeration.
, particularly preferably 1 x 10-5 to 1 x 10-2 equivalent/g
(resin) range.

The amount of the polar group-containing resin used is 0.1 to 50 parts by weight, more preferably 0.5 to 50 parts by weight, per 100 parts by weight of ferromagnetic powder.
It is preferably 40 parts by weight, especially 1 to 30 parts by weight. For the polar group-containing resin, consider not only the weight ratio but also the amount of polar groups in the resin, and set the amount of polar groups per 100 g of ferromagnetic powder to 1 x 10-6 to 1 x 10-2 equivalent/100 g of magnetic powder, and 2×10-6 to 1×10-2 equivalent/100g magnetic powder,
In particular, it is preferable to use 5×10 −6 to 5×10 −3 equivalents/100 g of magnetic powder.

The magnetic paint in the present invention includes the above-mentioned ferromagnetic powder, addition compound (A), and sulfonate-containing resin (B).
) in addition to conventionally known or used components. For example, binders such as thermoplastic resins, thermosetting resins, and reactive resins, abrasives, antistatic agents, reinforcing agents, dispersants, lubricants, and the like can be contained singly or in combination.

This thermoplastic resin has a softening temperature of 15
0℃ or less, average molecular weight 10,000-300,000
, with a degree of polymerization of about 50 to 2,000, such as vinyl chloride/vinyl acetate copolymer, vinyl chloride/vinylidene chloride copolymer, vinyl chloride/acrylonitrile copolymer, acrylic ester/acrylonitrile copolymer ,
Acrylic ester/vinylidene chloride copolymer, acrylic ester/styrene copolymer, methacrylic ester/acrylonitrile copolymer, methacrylic ester/vinylidene chloride copolymer, methacrylic ester/styrene copolymer, urethane elastomer, Nylon-silicon resin, nitrocellulose-polyamide resin, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivatives (cellulose acetate butyrate, cellulose diacetate, cellulose) triacetate, cellulose propionate, nitrocellulose, etc.), styrene-butadiene copolymers, polyester resins, chlorovinyl ether-acrylic acid ester copolymers, amino resins, various synthetic rubber-based thermoplastic resins, and mixtures thereof. used.

The thermosetting resin or reactive resin has a molecular weight of 200,000 or less in the state of a coating solution, and when heated after coating and drying, the molecular weight becomes infinite due to reactions such as condensation and addition. Become. Moreover, among these resins, those that do not soften or melt before the resin is thermally decomposed are preferable. Specifically, examples include phenol resins, epoxy resins, polyurethane curable resins, urea resins, melamine resins, alkyd resins, silicone resins, acrylic reaction resins, epoxy-polyamide resins, nitrocellulose melamine resins, high molecular weight polyester resins, and isocyanate resins. Mixtures of polymers, mixtures of methacrylate copolymers and diisocyanate prepolymers, mixtures of polyester polyols and polyisocyanates, urea formaldehyde resins, mixtures of low molecular weight glycols/high molecular weight diols/triphenylmethane triisocyanate, polyamine resins and the like. Examples include mixtures of the following.

These binders may be used alone or in combination. The mixing ratio of the ferromagnetic fine powder and the binder in the magnetic layer is based on 100 parts by weight of the ferromagnetic fine powder.
The binder is used in an amount ranging from 5 to 300 parts by weight.

As the polishing agent, commonly used materials such as fused alumina, silicon carbide, and chromium oxide (Cr2O3) are used.
), corundum, artificial corundum, diamond, artificial diamond, garnet, emery (main ingredients: corundum and magnetite), etc. are used. These abrasives have a Mohs hardness of 5 or more and an average particle size of 0.05 to 5 μm.
A size of 0.4 to 1 is effective, preferably 0.4 to 1.
It is 5 μm. These abrasives are added in an amount of 7 to 15 parts by weight based on 100 parts by weight of the binder. This amount is 7
If it is less than 15 parts by weight, sufficient durability will not be obtained, and if it is more than 15 parts by weight, the degree of filling will decrease and sufficient output will not be obtained.

[0038] As the antistatic agent, carbon black,
Conductive fine powder such as carbon black graft polymer; Natural surfactant such as saponin; Nonionic surfactant such as alkylene oxide type, glycerin type, glycidol type; Higher alkylamines, quaternary ammonium salts, pyridine and other complexes Cationic surfactants such as rings, phosphoniums or sulfoniums; anionic surfactants containing acidic groups such as carboxylic acids, sulfonic acids, phosphoric acids, sulfuric acid ester groups, and phosphoric ester groups; amino acids, aminosulfonic acids, and amino alcohols; Ampholytic activators such as sulfuric acid or phosphoric esters are used.

The above conductive fine powder is used in an amount of 0.2 to 20 parts by weight based on 100 parts by weight of the binder, and the surfactant is added in an amount of 0.1 to 20 parts by weight.
It is added in an amount of 10 parts by weight.

[0040] These surfactants are used alone or in combination, but are sometimes used for other purposes, such as dispersion, improving magnetic properties, improving lubricity, and as coating aids. .

Dispersants (pigment wetting agents) include carbon atoms such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, linolenic acid, and stearolic acid. 12~
22 fatty acids (R1 COOH, R1 has 11 to 11 carbon atoms)
22 alkyl or alkenyl groups); metal soaps made of alkali metals (Li, Na, K, etc.) or alkaline earth metals (Mg, Ca, Ba) of the above fatty acids; fluorine-containing compounds of the above fatty acid esters; Amides of the above fatty acids; polyalkylene oxide alkyl phosphates; lecithin; trialkyl polyolefin oxy quaternary ammonium salts (alkyl has 1 to 5 carbon atoms, olefins include ethylene, propylene, etc.); other coupling agents (for example, silane cups); ring agents, titanium coupling agents, etc.) are used. In addition, higher alcohols having 12 or more carbon atoms and sulfuric esters may also be used. These dispersants are added in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the binder.

As lubricants, dialkylpolysiloxanes (alkyl has 1 to 5 carbon atoms), dialkoxypolysiloxanes (alkoxy has 1 to 4 carbon atoms), monoalkylmonoalkoxypolysiloxanes (alkyl has 1 to 5 carbon atoms)
, alkoxy has 1 to 4 carbon atoms), silicone oil such as phenylpolysiloxane, fluoroalkylpolysiloxane (alkyl has 1 to 5 carbon atoms); conductive fine powder such as graphite; inorganic materials such as molybdenum disulfide, tungsten disulfide, etc. Fine powder; Plastic fine powder such as polyethylene, polypropylene, polyethylene/vinyl chloride copolymer, polytetrafluoroethylene; α-olefin polymer; Unsaturated aliphatic hydrocarbon that is liquid at room temperature (n-olefin double bond is the terminal A compound with approximately 2 carbon atoms bonded to the carbon of
0); Monobasic fatty acids with 12 to 20 carbon atoms and 3 to 20 carbon atoms
Examples include fatty acid esters consisting of 12 monohydric alcohols and fluorocarbons. These lubricants are added in an amount of 0.2 to 20 parts by weight based on 100 parts by weight of the binder.

[0043] As the curing agent, a low molecular weight isocyanate compound is preferably used. Examples of the low molecular weight isocyanate compound include tolylene diisocyanate, 4,4'
- Isocyanates such as diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, naphthylene-1,5-diisocyanate, o-toluidine diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, and products of the isocyanates and polyalcohols, Further, polyisocyanates produced by condensation of isocyanates can be exemplified. Commercially available trade names of these low molecular weight isocyanate compounds include Coronate L, Coronate HL, and Coronate 2.
030, Coronate 2031, Millionate MR, Millionate MTL (manufactured by Nippon Polyurethane Co., Ltd.), Takenate D-102, Takenate D-110N, Takenate D-200, Takenate D-202 (manufactured by Takeda Pharmaceutical Co., Ltd.), Desmodur L , Desmodule 1L, Desmodule N, Desmodule HL (manufactured by Sumitomo Bayer, Ltd.), and the like. These can be used alone or in combination of two or more by taking advantage of the difference in curing reactivity.

The magnetic paint in the present invention can be produced by a conventionally known method.

[0045] As the solvent used for preparing the magnetic paint, organic solvents are preferred. Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, and tetrahydrofuran; methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isopropyl acetate,
Ester solvents such as ethyl lactate, glycol acetate, and monoethyl ether; glycol ether solvents such as ether, glycol dimethyl ether, and dioxane; tar solvents (aromatic hydrocarbons, etc.) such as benzene, toluene, xylene, cresol, chlorobenzene, and styrene; );
Chlorinated hydrocarbons such as methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, and dichlorobenzene, N,N-dimethylformaldehyde, hexane, and the like can be used.

In kneading and dispersing the ferromagnetic powder and each of the above-mentioned components, the ferromagnetic powder and each of the components are fed into a dispersion machine either simultaneously or individually one after another. For example, there is a method in which magnetic powder is added to a solvent containing a dispersant and the like, and the dispersion is continued for a predetermined period of time to form a magnetic paint. At that time, it is preferable that the magnetic powder is brought into contact with the addition compound (A) in advance,
It is preferable to mix it with other components in this coexistence state. This makes the action of the addition compound (A) more effective.

Various types of dispersing machines can be used for kneading and dispersing the magnetic paint. For example, two-roll mill, three-roll mill, ball mill, pebble mill, tron mill, sand glider, Szegvari attritor, high-speed impeller dispersion machine, high-speed stone mill, high-speed impact mill, disperser, kneader, high-speed mixer, homogenizer, ultrasonic A disperser or the like can be used.

[0048] Also, as a technique related to kneading and dispersion, ``Paint Flow and Pigment Dispersion'' by T.C. Patton (1999)
The technique described in 1975) can be used.

[0049] Conventionally known methods can be used to apply the thus obtained magnetic paint onto a non-magnetic support. For example, two or more magnetic layers may be provided simultaneously by a multilayer simultaneous coating method.

By this method, the magnetic layer coated on the support is, if necessary, subjected to a treatment to make the magnetic material in the layer non-oriented as described above, and then the formed magnetic layer is dried. Further, if necessary, the magnetic disk is subjected to surface smoothing processing or punched into a desired shape.

The thickness of the magnetic layer is approximately 0.2 to 12 in terms of dry thickness.
The coating is applied to a thickness of 0.3 to 4 μm. In the case of multiple layers, the total amount falls within the above range. Further, this dry thickness may be determined depending on the use, shape, specifications, etc. of the magnetic disk.

This magnetic layer has extremely few surface defects caused by poor dispersion or re-agglomeration of the ferromagnetic powder, and has excellent surface smoothness, for example, a center line average roughness (Ra) of 0.020 μm.
This is a magnetic layer that is extremely smooth and has significantly improved recording characteristics at short wavelengths.

[0053]

[Examples] The present invention will be further explained below with reference to Examples. In addition, the characteristics in the example were determined by the following method.

1. Paint dispersion: A magnetic paint is applied to the surface of a polyethylene terephthalate film having a thickness of 75 μm to a thickness of 3.0±1.0 μm after drying, and is dried and smoothed. The obtained coating film is observed with a differential phase contrast microscope (magnification: 100 times), and the number of irregularities with a diameter of 20 μm or more within the field of view is counted in any one field of view, and this number is taken as the degree of paint dispersion.

2. Short wavelength recording characteristics Using a 3.5-inch floppy disk drive with a gap length of 0.3 μm and a ring-type Mn-Zn ferrite head, recording wavelengths of 0.7 and 1.5 were recorded at the optimum recording current.
Measure the output in μm. This output is shown assuming that the output of a standard disk is 0 dB.

3. High pass modulation adjacent 1
Measure the average signal strength in 00 bit units and divide these into A,
When B, it is shown as the average value of worst to 10 in [(A-B)/(A+B)]×100.

[0057]

[Examples 1 to 19, Comparative Examples 1 to 19] Hexagonal barium ferrite 80 parts by weight (specific surface area 50 m2 /g, coercive force 700
Oe) Shown in Table I (i) and (ii)
4 parts by weight addition compound (A) 4 parts by weight sulfonate-containing resin shown in Table I (i) and (ii) (B) Polyurethane
4 parts by weight (Dainippon Ink Chemical; Pandex T-
5250) PVC/PVC resin
4 parts by weight (Nissin Chemical Co., Ltd.; TA-5C) α alumina
3 parts by weight (Sumitomo Chemical; AKP-20) Carbon black
5 parts by weight (Mitsubishi Kasei: #3950) Oleic acid oleyl ester 5 parts by weight Cyclohexanone 400
After mixing and dispersing the composition consisting of parts by weight with a sand grinder, Coronate L
10 parts by weight (Japan Polyurethane: low molecular weight isocyanate) was added and further mixed in a high speed disperser to prepare a magnetic paint.

The obtained magnetic paint was aged at 15° C. for 24 hours, then applied on one side of polyethylene terephthalate with a thickness of 75 μm to a dry thickness of 2.5 μm, and dried after non-orientation treatment. Then, the magnetic layer was calendered. Furthermore, the same treatment was carried out on the back side. After heat treatment at 60° C. for 100 hours, a disk-shaped magnetic disk was produced. Table I shows the characteristics of this magnetic disk.

By using the addition compound (A),
As shown in Table I, the dispersibility of the paint, especially the dispersion stability, was significantly improved. Furthermore, when it comes to industrial products, it is undesirable for there to be variations in quality between the products at the beginning and end of production, but since the paint is stabilized by the use of the additive compound (A), variations in quality are also minimized (with short wavelengths). Recording characteristics and high-pass modulation).

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Examples 20 to 29 and Comparative Examples 20 to 27] Hexagonal barium ferrite 80 parts by weight (
Same as Example 1) Addition compound (A) shown in Table II
4 parts by weight Sulfone-containing resin (B) shown in Table II
7 parts by weight polyurethane (Toyo Morton Co., Ltd.; CA118) 5 parts by weight α-alumina (Sumitomo Chemical: AKP20) 3 parts by weight carbon black (Mitsubishi Kasei: #3950) 5 parts by weight oleyl oleate
5 parts by weight cyclohexanone
After mixing and dispersing 400 parts by weight of the composition using a sand grinder, the same procedure as in Example 1 was carried out to prepare a magnetic disk.

The characteristics of this paint and magnetic disk are described in Part II.
Shown in the table.

[0064]

[Table 3]

[0065]

[Examples 30 to 37, Comparative Examples 28 to 35] 70 parts by weight of ferromagnetic powder shown in Table III
Addition compound (A)
6 parts by weight sulfonate-containing binder (B)
6 parts by weight polyurethane
6 parts by weight (Dainippon Ink Chemical; Spandex T-5250) PVC/PVC resin
8 parts by weight (Nissin Chemical; TA-5C) α-alumina (Sumitomo Chemical; AKP-20) 4 parts by weight carbon black (Mitsubishi Kasei: #3950) 6 parts by weight oleyl oleate
6 parts by weight cyclohexanone
After mixing and dispersing the composition consisting of 400 parts by weight with a sand grinder, Coronate L
10 parts by weight (Japan Polyurethane: low molecular weight isocyanate) was added and further mixed in a high speed disperser to prepare a magnetic paint.

The obtained magnetic paint was aged at 15° C. for 24 hours and then dried on a polyethylene terephthalate film with a thickness of 75 μm. 2.7μ for ferromagnetic powder
The magnetic layer was coated so as to have an orientation of m, dried after non-orientation treatment, and then calendered to the magnetic layer. Thereafter, a magnetic disk was produced in the same manner as in Example 1.

The characteristics of this magnetic disk are shown in Table III.

[0068]

[Table 4]

[0069]

[Table 5]

[0070]

[Reference Example 1] 7.2 parts by weight of Desmodur N (75% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene) was dissolved in 20 parts by weight of xylene.The average molecular weight was 1800.
16.9 parts by weight of caprolactone polyester (obtained in Production A below) and 10 parts of ethyl cellosolve acetate
parts by weight and homogenized under a protective atmosphere, 0.004 parts by weight of dibutyltin dilaurate were added and the reaction mixture was stirred at 60° C. until complete reaction of the OH groups.

For the crosslinking reaction, the reaction mixture was diluted with 10 parts by weight of xylene and 0.8 parts by weight of 1,12-diaminododecane dissolved in 10 parts by weight of N-methyl-pyrrolidone were immediately added.

When 66% of the NCO groups initially subjected to the reaction had reacted, the reaction mixture was diluted with 13.2 parts by weight of xylene, and N,
1.9 parts by weight of N-diallylmelamine was added.

The reaction mixture was heated to 70° C. and stirred at this temperature for 1 hour.

The final product was a medium viscous, colorless, clear to slightly hazy material.

[Production of caprolactone polyester: Production A] 7.2 parts by weight of n-octanol, 92.8 parts by weight of caprolactone, and 0.0 parts by weight of dibutyltin dilaurate.
0.3 parts by weight were homogenized under a protective atmosphere and the
Heated to 60°C. The addition reaction was terminated as soon as a solids content of 99% was obtained. At this temperature this solids content was achieved in 10-12 hours. A product was obtained which was a colorless solid at room temperature, with a melting point of 50-60°C.

[0076]

[Reference Example 2] Desmodur N (75% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene) under a protective atmosphere
) 10.4 parts by weight was diluted with 10 parts by weight of ethyl cellosolve acetate and dissolved in 20 parts by weight of xylene, with an average molecular weight of 11.
00 caprolactone polyester (obtained in Preparation B below) was added. Dibutyltin dilaurate 0.0
After adding 0.4 parts by weight, the reaction mixture was heated to 60°C.

When 33% of the NCO groups initially subjected to the reaction had reacted, 0.6 parts by weight of trimethylolpropane dissolved in 30 parts by weight of xylene was added.

Immediately after 66% of the NCO groups had reacted, 4 parts by weight of ethyl cellosolve acetate was added.
1.6 parts by weight of -(2-hydroxyethyl)-pyridine were added and the reaction mixture was heated to 70°C and stirred at this temperature for 1 hour. The final product was colorless and of medium viscosity.

[Production of caprolactone polyester: Production B] 11.1 parts by weight of phenylethyl alcohol and 88.9 parts by weight of caprolactone were homogenized at room temperature, and 0.002 parts by weight of dibutyltin dilaurate was added as a catalyst under a nitrogen atmosphere.
Added parts by weight. The reaction mixture was heated to 160° C. within 1 hour and stirred at this temperature. The reaction was terminated as soon as a solids content of 99% was obtained.

Polyester has a melting point of 50 to 60°C.
% product or as a 50% mixture with xylene, for example. The latter was solid at room temperature and had a melting point of 40-50°C.

[0081]

[Reference Example 3] Desmodur N (75% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene) under a protective atmosphere
) 10.3 parts by weight, 20 parts by weight of ethyl cellosolve acetate,
And the average molecular weight dissolved in 15 parts by weight of xylene is 7
After homogenization with 50 commercially available methoxypolyethylene glycol and addition of 0.004 parts by weight of dibutyltin dilaurate, the reaction mixture was heated to 50°C.

After 1/3 of the NCO groups had reacted, 5.4 parts by weight of polyethylene glycol having an average molecular weight of 800 dissolved in 15 parts by weight of xylene was added.

When 66% of the NCO groups had reacted, the reaction mixture was diluted with 12.4 parts by weight of xylene and 1.7 parts by weight of 1-(2-aminoethyl)-piperazine dissolved in 10 parts by weight of ethyl cellosolve acetate. Added parts by weight. The reaction mixture was stirred at 70° C. for 2 hours, yielding a yellow, slightly viscous product.

[0084]

[Reference Example 4] 9.1 parts by weight of Desmodur N (75% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene), 17.7 parts by weight of ethyl cellosolve acetate, 0.003 parts by weight of dibutyltin dilaurate, and 10 parts by weight of xylene 13 parts by weight of caprolactone polyester having an average molecular weight of 1100 (obtained in Preparation B above) dissolved in parts by weight were homogenized under a protective atmosphere and heated to 50°C. After chemical addition of the polyester, ethoxylated oleylamine 3 with an average molecular weight of 630 dissolved in 30 parts by weight of xylene
．． 7 parts by weight were added.

As soon as 66% of the NCO groups have reacted, 4-(
1.5 parts by weight of 2-aminoethyl)-pyridine was added, and the reaction mixture was stirred for 1 hour to complete the reaction. After cooling, 0.8 parts by weight of acetic acid was added to perform a neutralization reaction. The product solution had a medium viscosity and was slightly cloudy and brown in color.

[0086]

[Reference Example 5] 7.6 parts by weight of Desmodur N (75% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene), 18.1 parts by weight of xylene, and adipic acid and dodecane dissolved in 10 parts by weight of xylene. Polyester of diol and octanol with an average molecular weight of 1400 (Production C below)
13.3 parts by weight (obtained in ) were homogenized under a protective atmosphere, 0.003 parts by weight of dibutyltin dilaurate were added and the reaction mixture was heated to 40°C. 66% of NCO groups
When the reaction has finished, trimethylolpropane-caprolactone polyester (
4.5 parts by weight (obtained in Production D below) was added.

After addition of the hydroxyl group, 1 part by weight of N,N-dimethyl-1,3-propanediamine dissolved in 15 parts by weight of N-methylpyrrolidone was added, and the reaction mixture was heated to 60° C. and stirred for 1 hour. . The product was highly viscous and colorless.

[Production of polyester: Production C] 38 parts by weight of adipic acid, 52.7 parts by weight of dodecanediol, 9.3 parts by weight of octanol, 0.0 parts by weight of p-toluenesulfonic acid.
1 part by weight and 30 parts by weight of toluene were homogenized and heated. The produced water was azeotropically distilled off within 5-6 hours and the temperature reached 140-150°C. The solvent was then carefully distilled under vacuum. The polyester produced was solid at room temperature and had a melting point of 70-80°C.

[Production of caprolactone polyester: Production D] 6 to 8 hours after adding 0.003 parts by weight of dibutyltin dilaurate using 9.6 parts by weight of trimethylolpropane and 90.4 parts by weight of caprolactone as catalysts.
The reaction was carried out at 170°C until a polyester having an average molecular weight of 1400 was obtained.

[0090]

[Reference Example 6] 12.9 parts by weight of Desmodur L (67% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene) was added to 20 parts by weight of a 1:1 mixed solvent of ethyl cellosolve acetate and xylene under a protective atmosphere. Diluted. 9 parts by weight of commercially available methoxypolyethylene glycol having an average molecular weight of 750 dissolved in 10 parts by weight of xylene and 0.003 parts by weight of dibutyltin dilaurate were added. 33 of NCO group at 50℃
%, 6 parts by weight of caprolactone polyester having an average molecular weight of 1000 dissolved in 20 parts by weight of xylene obtained in Preparation Example E below were added. 66 of NCO group
The reaction was stopped as soon as % had finished reacting. 1.4 parts by weight of 1-(2-hydroxyethyl)-imidazole dissolved in 20.7 parts by weight of xylene were added for the addition of the remaining NCO groups, and the reaction mixture was stirred at 70° C. for 2 hours.

A colorless, transparent and slightly viscous product was obtained.

[Production of polycaprolactone polyester: Production E] 9 parts by weight of 1,4-butanediol, 91 parts by weight of caprolactone, and 0.0 parts by weight of dibutyltin dilaurate.
002 parts by weight were homogenized under a protective atmosphere and heated to 160° C. within 1 hour. The addition reaction was terminated as soon as the solids content was above 99%. The produced polyester diol had an average molecular weight of 1000.

[0093]

[Reference Example 7] 14.3 parts by weight of a polyester of adipic acid, dodecanediol and octanol with an average molecular weight of 1400 (obtained in the above production C) was heated at 50°C with 15 parts by weight of ethyl cellosolve acetate and 10 parts by weight of xylene. under a protective atmosphere. The reaction mixture was cooled to 20° C. and 11.1 parts by weight of Desmodur L (67% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene) and 0.003 parts by weight of dibutyltin dilaurate were added with stirring. The reaction mixture was slowly heated to 50° C. and the progress of the reaction was followed by quantification of NCO groups. N.C.O.
After 1/3 of the groups have reacted, add polyethylene glycol 2 with an average molecular weight of 400 dissolved in 20 parts by weight of xylene.
．． 1 part by weight was added, leaving the remaining 1/3 of the NCO groups for the next reaction. The reaction mixture was then diluted with 11.4 parts by weight of xylene and diluted with N dissolved in 15 parts by weight of N-methylpyrrolidone.
, 1.1 parts by weight of N-dimethyl-1,3-diaminopropane were added. The reaction mixture was stirred at 50° C. for 1 hour, and further 0.75 parts by weight of acetic acid was added. The product was a slightly viscous yellow solution.

[0094]

[Reference Example 8] 8.8 parts by weight of Desmodur L (67% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene) in 15 parts by weight of ethyl cellosolve acetate was homogenized under a protective atmosphere, and nonylphenol ethyl oxylate was (ox
15.5 parts by weight of caprolactone polyester (obtained in Preparation F below), obtained starting from ylate) and dissolved in 12.2 parts by weight of xylene, were added together with 0.002 parts by weight of dibutyltin dilaurate. The reaction mixture was heated to 50° C. and stirred until 30% of the NCO groups had reacted. Next, the reaction solution was diluted with 20 parts by weight of xylene, and commercially available polytetrahydrofuran diol having an average molecular weight of 650 dissolved in 10 parts by weight of xylene was added.

As soon as 66% of the NCO groups have reacted, 0.9 parts by weight of 4-(aminomethyl)-pyridine dissolved in 15 parts by weight of xylene is added and the reaction mixture is heated to 70°C.
and stirred at this temperature for 1 hour. A colorless and very low viscosity product was obtained.

[Production of caprolactone polyester: Production F] 23.4 parts by weight of alkali-free dehydrated nonylphenol ethoxylate having an average molecular weight of 445 was mixed with 76.6 parts by weight of caprolactone and 0.004 parts by weight of dibutyltin dilaurate under a protective atmosphere. It was homogenized with The reaction mixture was heated to 150°C and stirred at this temperature for 20 hours. A colorless, waxy product with a solids content of 98% was obtained.

[0097]

[Reference Example 9] 12.4 parts by weight of ethyl cellosolve acetate, Desmodur L (1 part of ethyl cellosolve acetate and xylene)
11 parts by weight of 67%) and 2 parts by weight of xylene in a mixed solvent
14.2 parts by weight of a polyester with an average molecular weight of 1400 (obtained in Preparation C above) of adipic acid, dodecanediol and octanol dissolved in 0 parts by weight are homogenized under a protective atmosphere and 0.003 parts by weight of dibutyltin dilaurate are dissolved. added. The polyester was chemically added to Desmodur L by heating the reaction mixture to 50°C.

After this reaction step, 2.2 parts by weight of commercially available coconut diethanolamide dissolved in 30 parts by weight of a 1:1 mixture of ethyl cellosolve acetate and xylene were added. The average molecular weight of coconut oil diethanolamide is 440
Met. As soon as 2/3 of the NCO groups have reacted, 1.3 parts by weight of 1-(3-aminopropyl)-imidazole dissolved in 10 parts by weight of NMP are immediately added, and the reaction mixture is heated to 70°C and maintained at this temperature. The mixture was stirred for 1 hour. A clear to slightly cloudy product with medium viscosity was obtained.

0099

[Reference Example 10] Polyisophorone diisocyanate dissolved in 10 parts by weight of ethyl cellosolve acetate (70% in a 1:1 mixed solvent of ethyl cellosolve acetate and xylene) 7.9
parts by weight, and valerolactone polyester with an average molecular weight of 2000 dissolved in 20 parts by weight of xylene (Production G below)
(15 parts by weight) were homogenized under a protective atmosphere excluding moisture. Dibutyltin dilaurate 0.003
parts by weight were added and the reaction mixture was heated to 50°C. When the OH groups have completely reacted, polypropylene glycol 3 with an average molecular weight of 1000 dissolved in 20 parts by weight of xylene
．． 7 parts by weight were added.

When 66% of the NCO groups have reacted, 7.6 parts by weight of xylene and 15 parts by weight of N-methylpyrrolidone
0.8 parts by weight of 3-mercapto-1,2,4-triazole dissolved in parts by weight were added, and the reaction mixture was stirred at 60°C for 1 hour.

The product solution had a low viscosity and a slightly brown color.

[Production of valerolactone polyester: Production G] 2.1 parts by weight of commercially available heptadecafluorodecanol having an average molecular weight of 445 was added at 60°C under a protective atmosphere.
It was homogenized with 5.9 parts by weight of 2-ethylhexanol and 92 parts by weight of valerolactone. 0.004 parts by weight of dibutyltin dilaurate was added to the reaction mixture and 18
Heated to 0°C. The reaction mixture was stirred until the solids content was 98%.

A colorless to slightly yellowish solid product was obtained at room temperature, with a melting point of 60-70°C.

[0104]

[Reference Example 11] Desmodur HL (6 in butyl acetate)
Caprolactone polyester (0%) with an average molecular weight of 1100 was dissolved in 20 parts by weight of ethyl acetate cellosolve from which moisture had been removed, and 20 parts by weight of xylene.
11.6 parts by weight of the product obtained in Preparation B) and 0.003 parts by weight of dibutyltin dilaurate were added, and the reaction mixture was gently heated to 60°C.

The first step was completed as soon as 30% of the NCO groups had reacted.

Xylene 14. for the coupling reaction.
3.4 parts by weight of commercially available polytetrahydrofuran diol having an average molecular weight of 650 dissolved in 4 parts by weight were added.

As the final step following completion of 60% reaction of NCO groups, 1.5 parts by weight of 3-mercapto-1,2,4-triazole dissolved in 15 parts by weight of N-methylpyrrolidone was added, and the reaction mixture was reduced to 70% by weight. ℃ and stirred at this temperature for 1 hour. The product solution was viscous, slightly yellow and almost clear.

[0108]

Reference Example 12 The reaction was carried out at 50°C under a protective atmosphere. Desmodur HL (60% in butyl acetate) 14.4
part by weight of ethyl cellosolve acetate was dissolved in 15 parts by weight of ethyl cellosolve acetate to obtain caprolactone polyester having an average molecular weight of 1100 obtained starting from phenylethyl alcohol (preparation B above).
9.9 parts by weight of the product obtained in Example 1) were added. The polyester was partially dissolved in 13 parts by weight of xylene.

When the addition reaction of the polyester was completed by quantifying the NCO groups, 4.5 parts by weight of polyethylene glycol having an average molecular weight of 1000 was added. In order to react with the remaining NCO groups, 1-(2-aminoethyl)-
2.3 parts by weight of piperazine were added and the reaction mixture was diluted with xylene to a solids content of 30%. A slightly cloudy viscous solution was added as product.

[0110]

[Reference Example 13] Desmodur HL (6 in butyl acetate)
0%) was diluted with 30 parts by weight of a 1:1 mixture of xylene and ethyl cellosolve acetate under protective gas to give 12.7 parts by weight of polyester with an average molecular weight of 2000 (obtained in Preparation G above). Added a section. After adding 0.003 parts by weight of dibutyltin dilaurate, the addition reaction was carried out at room temperature.

When 25% of the NCO groups had reacted, 4.7 parts by weight of polyethylene glycol having an average molecular weight of 1500 was added as a second step.

When 50% of the NCO groups have reacted, the reaction mixture is diluted with xylene to a final solid product content of 25% and 1.5 parts by weight of 4-(2-aminoethyl)-pyridine is added. added. heating the reaction mixture to 60°C;
Stirred at this temperature for 1 hour. A slightly yellow and viscous product was obtained.

[0113]

Reference Example 14 The reaction was carried out at 50°C under a protective gas. 6.3 parts by weight of Desmodur HL (60% in butyl acetate) was mixed with 15 parts by weight of ethyl cellosolve acetate and 36 parts by weight of xylene.
Diluted with a mixed solution of 0.7 parts by weight of polyethylene glycol with an average molecular weight of 400 and an average molecular weight of 5000.
19.6 parts by weight of caprolactone polyester (obtained in Production H below) were added. 0.002 parts by weight of dibutyltin dilaurate was added to accelerate the reaction.

When all OH groups have reacted, 4-
0.9 parts by weight of (2-hydroxyethyl)-pyridine was added and the solids content of the reaction mixture was adjusted to 25% with xylene. The reaction mixture was stirred at 60° C. for 1 hour until the reaction was complete. A colorless, low viscosity product was obtained.

[Production of caprolactone polyester: Production H] 2.9 parts by weight of isononanol, 9 parts by weight of caprolactone
7.1 parts by weight and 0.00 parts of dibutyltin dilaurate
2 parts by weight were homogenized under a protective atmosphere to give 17% within 1 hour.
Heated to 0°C. The reaction was terminated as soon as a solids content of 99.5% was obtained after 8-10 hours. A product was obtained which was a colorless solid at room temperature, with a melting point of 60-70<0>C.

[0116]

[Reference Example 15] Desmodur HL (6 in butyl acetate)
0%) 10.7 parts by weight of xylene 15 under a protective atmosphere.
．． Obtained starting from 7 parts by weight and heptadecafluorodecanol/2-ethylhexanol, average molecular weight 2000
was homogenized with a solution of 16.2 parts by weight of valerolactone polyester (obtained in Preparation G above). 0.001 part by weight of dibutyltin dilaurate was added, and the polyester addition reaction was carried out at 50°C.

After the reaction was completed, the reaction mixture was diluted with 20 parts by weight of ethyl cellosolve acetate, and 0.3 parts by weight of 1,4-butanediamine dissolved in 20 parts by weight of xylene was added.

As soon as 55% of the NCO groups had reacted, the slightly exothermic reaction was stopped by adding 2.1 parts by weight of 2-amino-6-methoxybenzothiazole dissolved in 15 parts by weight of NMP. The reaction mixture was heated to 70°C and stirred for 1 hour.

A slightly viscous, yellow, and transparent solution was obtained as the product.

[0120]

[Reference Example 16] Desmodur IL (5 in butyl acetate)
1%) and 11 parts by weight of caprolactone polyester with an average molecular weight of 1800 (obtained in Preparation A above) dissolved in 20 parts by weight of xylene were dissolved in 20 parts by weight of ethyl cellosolve acetate/xylene (1:1). Added under a protective atmosphere and 0.0% dibutyltin dilaurate as catalyst.
After adding 0.002 parts by weight, an addition reaction was carried out at room temperature.

When 20% of the NCO groups had reacted, 3.8 parts by weight of polycaprolactone polyester (obtained in Preparation E above) dissolved in 17.1 parts by weight of xylene were added.

After 55% of the NCO groups have reacted, 2.0 parts of 4-(2-aminoethyl)-pyridine dissolved in 10 parts by weight of xylene and 10 parts by weight of isobutyl ketone is added.
Added parts by weight. The reaction mixture was heated to 50°C and stirred for 1 hour. A colorless, slightly yellow and low viscosity product was obtained.

[0123]

[Reference Example 17] Desmodur IL (5 in butyl acetate)
1%) 9 parts by weight of polyester with an average molecular weight of 5000 (
17 parts by weight of the product obtained in Production H) and 25 parts by weight of xylene
The mixed solution with parts by weight was homogenized under a protective atmosphere excluding moisture, and 0.003 parts by weight of dibutyltin dilaurate was added. The reaction was carried out at 60°C. After the polyester addition reaction, 30 parts by weight of xylene with an average molecular weight of 10
2.5 parts by weight of polypropylene glycol No. 00 was added. Dibutyltin dilaurate 0.0 to accelerate the reaction
02 parts by weight were added. When the hydroxyl groups have finished reacting, the reaction mixture is diluted with 5.6 parts by weight of xylene, and the remaining NCO groups are dissolved in 10 parts by weight of N-methylpyrrolidone and 0.9 parts by weight of 3-mercapto-1,2,4-triazole. Added a section. A medium viscous, yellow product was obtained.

[0124]

[Reference Example 18] Desmodur IL (5 in butyl acetate)
1%) 15.5 parts by weight of xylene 15 under a protective atmosphere.
Polyester with an average molecular weight of 1800 dissolved in parts by weight (
The mixture was homogenized with 13.3 parts by weight (obtained in Preparation A), 0.003 parts by weight of dibutyltin dilaurate was added, and the reaction mixture was heated to 50°C. After the addition reaction of the polyester (25% of the NCO groups reacted, which can be seen quantitatively), the reaction mixture was diluted with 20 parts by weight of xylene and 1.
0.7 parts by weight of 12-diaminododecane was added.

After an exothermic reaction, 14 parts by weight of xylene and N-
1.5 parts by weight of N,N-dimethyl-1,3-propanediamine dissolved in 20 parts by weight of methylpyrrolidone was added. Stirring at 70° C. for 1 hour gave a medium viscous and slightly cloudy product.

[0126]

[Reference Example 19] Desmodur IL (5 in butyl acetate)
1%) under a protective atmosphere, 30 parts by weight of xylene/butyl acetate (4:1) and an average molecular weight of 180
0 polyester (obtained in production A above) 26.
It was homogenized to 6 parts by weight. Dibutyltin dilaurate 0.
When 003 parts by weight were added and the reaction mixture was heated to 50°C, 50% of the NCO groups had reacted.

0.3 parts by weight of 1,4-butanediol dissolved in 30 parts by weight of xylene was added. 75% of NCO groups
When the reaction has finished, 0.6 parts of 3-amino-1,2,4-triazole dissolved in 10 parts by weight of N-methylpyrrolidone
parts by weight were added and the solids content was adjusted to 30% with xylene. The medium viscous, yellow product was stirred at 60° C. for 1 hour.

A synthesis example of the sulfonate-containing resin (B) is as follows.

[0129]

[Reference Example 101] A 1000 ml four-necked flask equipped with a stirring device, nitrogen inlet tube, thermometer, and reflux condenser was placed in an oil bath, and 1.2 g of 2-acrylamido-2-methylpropanesulfonic acid was added to the flask. 140.8 g of butyl methacrylate and 200 ml of ethanol are charged and stirred. After setting the bath temperature so that the internal temperature was 60℃ while passing nitrogen gas, 2,2'-azobis-(2,4
Add 20 ml of an ethanol solution in which 0.8 g of -dimethylvaleronitrile) is dissolved. Polymerization starts and the reaction solution gradually becomes viscous after about 1 hour. 20 ml of an ethanol solution in which 0.8 g of 2,2'-azobis-(2,4-dimethylvaleronitrile) was dissolved was added for 4 hours for 2 hours from the start of polymerization.
The mixture was further added at 60° C. and stirred at 60° C. for a total of 8 hours to complete polymerization. After the reaction solution was cooled to 30°C, it was reprecipitated in 5 liters of water, the powder was filtered, and vacuum dried at 40°C for 12 hours to obtain 130.0 g of the desired product. The sulfonic acid content determined by alkaline titration was 1.1 mol%. The intrinsic viscosity [η] measured with methyl ethyl ketone is 0.10
Met.

[0130]

[Reference Example 102] In a 500 ml stainless steel autoclave equipped with an electromagnetic induction stirrer and a pressure gauge, 0.6 g of polyvinyl alcohol was dissolved in 300 ml of nitrogen-substituted distilled water and 0.1 ml of azobisisobutyronitrile.
5g, vinyl acetate 10.0g, 2-acrylamide-2
- After adding 8.0 g of methylpropanesulfonic acid, the lid is closed and the autoclave is cooled to -20°C in a dry ice-methanol bath. Next, after purging with nitrogen gas, 100 g of cooled liquid vinyl chloride was quickly added using a sufficiently cooled funnel, the temperature was raised to 60°C in about 15 minutes, polymerization was carried out with stirring, and the mixture was placed in an autoclave. The polymerization is terminated when the pressure starts to decrease. After cooling to room temperature and removing residual vinyl chloride monomer, the atmosphere was replaced with nitrogen gas, and the resulting white powder polymer was thoroughly washed with water, filtered under suction, and vacuum-dried at 40° C. for 12 hours. The yield was 95.0 g, and the copolymerization ratio (molar ratio) of vinyl chloride, vinyl acetate, and 2-acrylamido-2-methylpropanesulfonic acid was 9 from elemental analysis and alkaline titration.
The ratio was 0.0:7.5:2.5.

Intrinsic viscosity measured with methyl ethyl ketone [
η] was 0.21.

[0132]

[Reference Example 103] A pressure-resistant container equipped with a stirrer was purged with nitrogen, and the following items were charged into the container.

Deionized water 13
2.0 parts by weight vinyl chloride
36.1 parts by weight vinyl acetate
23.0 parts by weight Sodium (
1-allylcarboxy-2-dodecylcarboxy)1-
ethyl sulfonate
4.8 parts by weight Ammonium persulfate salt 0.5
Part by weight The reaction was started by raising the temperature of the above mixture to 55° C. while stirring, maintaining an internal pressure of 6.5 kg/cm 2 G, and then continuously pressurizing 36.1 parts by weight of vinyl chloride for reaction. As the addition of vinyl chloride was completed in 8 hours, the internal pressure gradually decreased, and after 12 hours, the pressure decreased to 0 kg/cm2 G, so the aging reaction was carried out for another 1 hour to obtain a uniform emulsion.

When 10 parts by weight of sodium chloride, 10 parts by weight of 5% dilute hydrochloric acid, and 100 parts by weight of hot water were added to 100 parts by weight of the obtained emulsion, the emulsion was broken and turned into a slurry. Filter this slurry with a filter cloth,
The cake was dispersed and washed in 500 parts by weight of water and filtered. The water washing and filtration operation was repeated five times, and the resulting cake-like product was dried to obtain 94 parts by weight of white copolymer powder. The copolymer obtained by the above synthesis method is referred to as Reference Example 103.

[0135]

[Reference Example 104] A pressure-resistant container equipped with a stirrer was purged with nitrogen, and the following items were charged into the container.

Methyl isobutyl ketone 43.0 parts by weight Methyl acetate 1
40.0 parts by weight vinyl chloride
72.0 parts by weight vinyl acetate
24.8 parts by weight Sodium (1-allylcarboxy-2-dodecylcarboxy) 1
-ethyl sulfonate
3.2 parts by weight Diisopropyl peroxydicarbonate (polymerization initiator) 1.0 parts by weight The above mixture was heated to 50°C with stirring to start the reaction, and a solution was prepared in which the ratio of polymerization initiator: methyl isobutyl ketone was 1:10. were continuously press-fitted. At this time, the internal pressure is 1.2 kg/cm2 G
Met. 12 hours after the start of the reaction, the internal pressure was 0.5 kg/cm.
2 G, so it was cooled to 30°C, and the vapor consisting of residual vinyl chloride and some solvent was collected through a -20°C condenser, and then vacuumed to -0.5 kg/cm2 G and collected, and then transferred to the reactor. 250 parts by weight of a copolymer solution having a solid content concentration of 34.5% and a viscosity of 78 cps (25° C.) was obtained from the above. Reference Example 1 The copolymer obtained by the above synthesis method was
04.

[0137]

[Reference Example 105] In an autoclave equipped with a stirring device,
400 parts by weight of methanol, 68 parts by weight of vinyl chloride, 36 parts by weight of vinyl acetate, 16 parts by weight of PEOVA+10 (vinyl persatate, trade name manufactured by Shell Chemical Co., Ltd.), 12 parts by weight of allyldodecyl sulfosuccinate Na salt, di(2- 6 parts by weight of (ethylhexyl) peroxydicarbonate and 2 parts by weight of partially saponified polyvinyl alcohol were charged, the temperature was raised to 50°C with stirring under a nitrogen gas atmosphere to start the reaction, and 68 parts by weight of vinyl chloride was added for 8 hours. In short, continuous pressure injection was carried out to cause a copolymerization reaction.

[0138] The autoclave internal pressure was 0.5 after 12 hours.
kg/cm2G, so release the residual pressure, cool it, and
The copolymer was washed three times with 000 parts by weight of methanol and filtered to obtain a cake-like copolymer. Next, this cake-like copolymer was charged into a saponification apparatus equipped with a stirrer according to the following recipe and saponified.

Cake-like copolymer 3
42 parts by weight (160 parts by weight of copolymer, 18 parts by weight of methanol)
2 parts by weight) methanol
718 parts by weight acetone
100 parts by weight sodium hydroxide
After saponifying 8 parts by weight at 40°C for 6 hours, 10 parts by weight of acetic acid was added, washed three times with 1000 parts by weight of methanol, further washed twice with 1000 parts by weight of deionized water, filtered and dried, 133 parts by weight of copolymer powder (Reference Example 105) was obtained.

[0140]

[Reference Example 106] Polymerization was carried out under the same polymerization conditions as in Reference Example 101 with the following charges.

Methanol
400 parts by weight vinyl chloride
72 parts by weight Vinyl propionate 28 parts by weight PEOVA+10 (mentioned above) 24 parts by weight Sodium vinyl sulfonate 4
Parts by weight Di(2-ethylhexyl) peroxydicarbonate 6 parts by weight Partially saponified polyvinyl alcohol 2 parts by weight Additional vinyl chloride
72 parts by weight The polymer thus produced was saponified according to the saponification conditions of Reference Example 101 using the following recipe.

Cake-like copolymer 3
50 parts by weight (168 parts by weight of copolymer, 18 parts by weight of methanol)
2 parts by weight) methanol
718 parts by weight acetone
100 parts by weight sodium hydroxide
8 parts by weight Thus, 151.2 parts by weight of saponified copolymer powder (Reference Example 106) was obtained.

[0143]

[Reference Example 107] After replacing nitrogen in an autoclave equipped with a stirring device, 982 g of vinyl chloride, 200 g of vinyl acetate,
Vinyl butyrate 80g, allyl glycidyl ether 5
3 g, 67 g of 30% sodium vinyl sulfonate, 2000 g of deionized water, 23 g of Emar 0 (sodium lauryl sulfate, trade name manufactured by Kao Corporation), Octabol #400 (polyoxyethylene octylphenyl ether, Sanyo Chemical (
Co., Ltd. (trade name)), 24 g of Triclean, 6 g of sodium carbonate, and 24 g of potassium persulfate were respectively charged, and the temperature was raised to 60° C. while stirring to start the reaction, and the copolymerization reaction was carried out over 7 hours. Autoclave internal pressure is 0.5kg/cm
2 G, the residual pressure was released and the emulsion was cooled. 3,500 g of methanol was added to the resulting emulsion, stirred at 60°C for 1 hour to form a slurry, then cooled, the copolymer slurry was taken out, and after filtration, 3,500 g of methanol was added. The copolymer powder was washed three times with deionized water, filtered, and dried to obtain 1116 g of copolymer powder. This product contains 79.2% vinyl chloride and 12% vinyl acetate.
It was a copolymer with an average degree of polymerization of 360, consisting of 8% vinyl butyrate, 4.8% vinyl butyrate, 2.7% allyl glycidyl ether, and 0.5% sodium vinylsulfonate.

[0144] This copolymer 5 was placed in a reactor equipped with a cooling tube.
After adding 00 g of methanol, 700 g of acetone, 300 g of acetone, and 20 g of caustic soda and carrying out a saponification reaction at 50° C. for 5 hours, the mixture was cooled to room temperature, and unreacted caustic soda was neutralized with 25 g of acetic acid. Add 1000g of methanol to
The mixture was washed twice with 1000 g of deionized water, and filtered and dried to obtain 440 g of modified copolymer powder (Polymer 1). This product consists of 84.5% vinyl chloride, 6.9% vinyl alcohol, 0.1% vinyl acetate, 5.1% vinyl butyrate, 2.9% allyl glycidyl ether, and 0.5% sodium vinyl sulfonate. The average degree of polymerization was 350.

[0145]

[Reference Example 108] After replacing nitrogen in an autoclave equipped with a stirrer, 477 g of vinyl chloride, 178 g of vinyl acetate, 221 g of vinyl caprate, 6 g of allyl glycidyl ether
9g, sodium methallylsulfonate 52g, deionized water 2
160g, Emar 0 (mentioned above) 24g, Octaball #
400 (mentioned above), 24 g of trichloride, 6 g of soda carbonate, and 24 g of potassium persulfate were each charged, and the temperature was raised to 60°C with stirring to start the reaction, and 477 g of vinyl chloride was continuously pressurized over 8 hours. A polymerization reaction was carried out.

[0146] Autoclave internal pressure is 0.5 kg/cm2
G, the residual pressure was released and the emulsion was cooled, and the obtained emulsion was subjected to methanol salting out by the same post-treatment procedure as in the previous example, and dried to obtain 1142 g of copolymer powder. This product contains 75.1% vinyl chloride and 10% vinyl acetate.
It was a copolymer with an average degree of polymerization of 320, consisting of 9.7% vinyl caprate, 3.2% allyl glycidyl ether, and 1.1% sodium methallylsulfonate.

[0147] This copolymer 50 was placed in a reactor equipped with a cooling tube.
After adding 0 g of methanol, 700 g of benzene, and 17.5 g of caustic soda and reacting at 50° C. for 5 hours, the mixture was cooled to room temperature, and unreacted caustic soda was neutralized with 30 g of acetic acid. This was washed four times with 1000 g of methanol and twice with 1000 g of deionized water, filtered and dried to obtain 432 g of modified copolymer powder (Polymer 2), which contained 79.3% vinyl chloride, Vinyl alcohol 5.9%, vinyl caprate 10.2%, allyl glycidyl ether 3.4%, sodium methallyl sulfonate 1
．． 2%, and the average degree of polymerization was 320.

[0148]

[Reference Examples 109 to 112] In a four-necked flask equipped with a thermometer, stirrer, dropping funnel, and condenser with drying tube,
100 g of 4'-diphenylmethane diisocyanate, 284 g of cyclohexanone and 28 g of methyl ethyl ketone
4 g was charged, the internal temperature was raised to 80°C, and the mixture was stirred. To this, the polycaprolactone diol (a) obtained in the above (1) 0
．． Commercially available polybutylene adipate (N-400g: manufactured by Nippon Polyurethane) with a weight of 95g and a number average molecular weight of 1000 26
5.7 g was added dropwise. After the dropwise addition was completed, a heating reaction was carried out at 80° C. for 2 hours to synthesize a prepolymer having isocyanate groups at the terminals. This prepolymer was then added dropwise to 12.6 g of 1,4-butanediol. 90 minutes after completion of dripping
A heating reaction was carried out at ℃ for 6 hours to form a polyurethane resin (A).
I got it. The completion of the reaction is indicated by the infrared absorption spectrum.
This was confirmed by the disappearance of the absorption of isocyanate groups at 2250 cm-1. In addition, the content of sodium sulfonate base in the obtained polyurethane resin was 2.5 μeq
/g.

[0149] Using the same method as Reference Example 109, Section IV
Reference Examples 110, 111, and 112 were produced from the raw materials shown in the table [see Table IV].

[0150]

[Table 6]

[0151]

[Reference Examples 113-115] 500 g of ε-caprolactone and 0.35 g of di-2-hydroxyethyl sodium 5-sulfoisophthalate salt were placed in a four-necked flask equipped with a thermometer, stirrer, condenser with drying tube, and nitrogen inlet tube. , 3.06 g of ethylene glycol and 0.10 g of tetrabutyl titanate were added, the internal temperature was maintained at 150°C, and the reaction was carried out for 10 hours to obtain the polyester resin of the present invention (Reference Example 113)
was manufactured. Obtained polyester resin (Reference Example 113
) had a number average molecular weight of 10,000 and a sodium sulfonate base content of 2 μeq/g.

Polyester resins, Reference Examples 113, 114 and 115 shown in Table V were produced using the raw materials and amounts shown in Table V and in the same manner as for the polyester resin (Reference Example 113).

[0153]

[Table 7]

[0154]

[Reference Examples 116-117] Production of polyester polyol In a reaction vessel equipped with a thermometer, a stirrer, and a partial reflux condenser, 582 parts of dimethyl terephthalate, 296 parts of dimethyl 5-sodium sulfoisophthalate, 434 parts of ethylene glycol, and neopentyl were added. Add 28 parts of glycol, 0.66 parts of zinc acetate, and 0.08 parts of sodium acetate to 1
Transesterification reaction was carried out at 40-220°C for 3 hours. Next, 1212 parts of sebacic acid was added and heated to 210-250°C.
After reacting for 2 hours, the reaction system was heated to 20 m
The pressure was reduced to mHg, and the polycondensation reaction was further carried out at 5 to 20 mmHg and 250°C for 50 minutes. The obtained polyester polyol [P] had ηsp/c=0.182 and a hydroxyl value of 38. From NMR analysis and the like, its composition was as follows. Terephthalic acid 30%, 5-sodium sulfoisophthalic acid 10 mol%, sebacic acid 60
mol%, 44 mol% ethylene glycol, 56 mol% neopentyl glycol.

Polyester polyol [Q] was obtained in the same manner. Its ηsp/c=0.130, and the hydroxyl value was 49. Its composition is 80% adipic acid
mol%, 5-sodium sulfoisophthalic acid 20 mol%
, 67 mol% ethylene glycol, 33 mol% 1,5-pentanediol.

Production of polyurethane resin In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 1280 parts of toluene, 850 parts of methyl isobutyl ketone, 1000 parts of polyester polyol [A], 71 parts of diphenylmethane diisocyanate, and 1 part of dibutyltin dilaurylate were added. .2 parts were added and reacted at 70 to 90°C for 8 hours. The sulfonic acid metal base of the obtained polyurethane resin [I] was 378 equivalents/106 g, and the molecular weight was 1800.
It was 0. Polyurethane resin [II] was obtained in the same manner using 50 parts of polyester polyol [P] and 950 parts of polyester polyol [Q]. The content of sulfonic acid metal base was 365 equivalents/106 g, and the molecular weight was 28,000.

The glass transition temperature of polyurethane resin [I
] was 28°C, and polyurethane resin [II] was -13°C.

Polyurethane resin [I
] is referred to as Reference Example 116, and polyurethane resin [II] is referred to as Reference Example 117.

[0159]

Effects of the Invention According to the present invention, the dispersibility and dispersion stability of ferromagnetic powder in a magnetic coating material are improved, the surface smoothness of the magnetic coating film is improved, and excellent magnetic recording properties, especially high-density magnetic recording. A flexible magnetic disk with specific properties can be provided.

Claims (2)

[Claims] 1. A flexible magnetic disk comprising a coating of magnetic paint containing ferromagnetic powder on a non-magnetic support, wherein the magnetic paint contains an average of 2.5 to 6 particles in each molecule. polyisocyanate having an isocyanate group, an addition compound derived from a compound reactive with the isocyanate group (A
) and a resin (B) having a sulfonate. 2. The flexible magnetic disk according to claim 1, wherein the ferromagnetic powder is hexagonal ferrite powder.