JPH05230399A - Article coated with magnetic coating compound - Google Patents

Abstract

PURPOSE:To obtain a new magnetic coating compound useful as a high- performance magnetic recording medium having excellent dispersibility magnetic recording powder, surface smoothness, durability, wear resistance, etc., of magnetic recording medium, comprising a specific block copolymer and magnetic powder as essential components. CONSTITUTION:The objective article coated with a magnetic coating compound comprising (A) a block copolymer having a polyurethane segment and a vinyl polymer segment and (B) magnetic powder (e.g. gamma-ferrite) essential components. The component A, for example, is obtained by a method for polymerizing a vinyl monomer in the presence of a polyurethane type polymer polyazo initiator prepared by reacting a compound such as azobiscyanopropanol containing both one diazo bond and two or more hydroxyl groups with a polyisocyanate compound and a polyol compound. A sulfonic group-containing monomer such as p-styrenesulfonic acid is preferably used as the vinyl monomer in terms of improvement in dispersibility, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel and useful magnetic paint-coated article coated with a specific magnetic paint. More specifically, the present invention relates to a magnetic paint-coated article coated with a specific magnetic paint, which comprises a block copolymer having both a polyurethane segment and a vinyl polymer segment, magnetic powder, and polyurethane as essential components.

Such a novel form of the magnetic coating material of the present invention exerts an epoch-making effect especially for magnetic recording media such as magnetic tapes, magnetic cards, prepaid cards and magnetic disks. The magnetic paint-coated article coated with such a magnetic paint is widely used as a high-performance magnetic recording medium for various applications as described above.

[0003]

2. Description of the Related Art In recent years, along with advances in hardware technology such as 8 mm video in audio / visual, DAT or S-VHS, remarkable advances in hardware in computers, and higher recording media density, etc. Performance requirements for audio tapes, home-use VTR tapes, magnetic tapes for computers, and floppy disks are becoming higher.

In particular, there is a demand for high reliability in recording / reproducing, and in particular, in video tapes, in addition to such high reliability, high image quality in recording / reproducing is required. Specifically, in addition to high recording density for reproducing clear images and sounds, it can withstand high-speed long-time running under severe conditions such as high temperature and high humidity, and the magnetic layer It is required that the powder does not fall off.

It is an important function of the binder to maintain the characteristics or physical properties of the magnetic layer, and the excellent dispersibility of the magnetic powder, high sensitivity, high SN ratio and high CN ratio. In view of the above, it is required that excellent electromagnetic characteristics can be obtained and, in addition, that durability such as wear resistance and wet heat resistance is excellent.

[0006] Various binders have been studied so far in order to satisfy such various physical properties, and the magnetic layer is provided with good abrasion resistance to improve the durability of the magnetic recording medium. , As the main binder, vinyl chloride-
A blend of a vinyl acetate copolymer (a vinyl chloride-vinyl acetate copolymer) and a polyurethane resin is used.

However, depending on the degree of compatibility between the vinyl chloride-vinyl acetate copolymer and the polyurethane resin, the dispersibility of the magnetic powder, the surface smoothness of the resulting magnetic recording medium, the durability, etc. may become poor. The fact is that many things that are sufficiently satisfied have not yet been obtained, and it goes without saying that even a magnetic paint-coated article coated with such a magnetic paint will be sufficiently satisfied. The reality is that some have not been obtained.

[0008]

Therefore, the inventors of the present invention stand on the basis of the recognition of the present situation, the drastic solution of various unsolved problems in the prior art, and the urgent demand in the industry. As a result of intensive studies, a block copolymer having a polyurethane segment and a vinyl polymer segment, for example, at least one in one molecule,
General formula

[0009]

[Chemical 7]

(Wherein R ₁ is an alkylene group, a cyclic alkylene group, an alkylene group having an ester group, a benzene ring or an alkylene group containing a benzene ring,
R ₂ and R ₂ 'may each be the same or different, an alkylene group, an alkylene group containing a cyano group, an alkylene group containing an amide bond, or an alkylene group having both an amide bond and a hydroxyl group. Shall represent a group. ) Structural unit, that is, the diazo bond and the general formula

[0011]

[Chemical 8]

(In the formula, R ₃ represents a polyol residue.) In the presence of a compound having a structural unit, ie, a urethane bond, at least 1
A coating containing a block copolymer obtained by polymerizing two kinds of polymerizable unsaturated monomers as an essential component is used for dispersibility of magnetic powder, surface smoothness of magnetic recording medium, durability and abrasion resistance. The present invention has been completed by finding that an excellent magnetic coating material can be obtained, and that a magnetic coating material-coated article coated with such a magnetic coating material can be an excellent magnetic recording medium.

[0013]

Specifically, the present invention comprises a magnetic powder and a block copolymer having a polyurethane segment and a vinyl polymer segment, respectively, as essential components, and a specific powder. It is intended to provide a new and useful magnetic paint-coated article coated with a magnetic paint.

Here, the above block copolymer having both a polyurethane segment and a vinyl polymer segment is, for example, an anion or a vinyl polymer anion or a vinyl polymer cation obtained by anionic polymerization or cationic polymerization. A method of synthesizing by means of reacting a polyurethane having a functional group capable of forming a bond by reacting with a cation as a terminating agent,

A method using a telechelic vinyl polymer synthesized by using a functional group-containing azo initiator such as a hydroxyl group or a carboxyl group, or a peroxide, for example, hydroxyl groups at both ends It may be synthesized by the reaction of a vinyl polymer containing with polyurethane diisocyanate, or by using various azo compounds or organic peroxides having a hydroxyl group, an amino group, a carboxyl group or an acid chloride group. Various kinds of polymer initiators,
A method of synthesizing by polymerizing a vinyl monomer and the like can be mentioned. Here, if a method of using a high molecular weight azo initiator which is one example of them is described in detail,
At least one general formula in a molecule

[0016]

[Chemical 9]

(Wherein R ₁ is an alkylene group, a cyclic alkylene group, an alkylene group having an ester group, a benzene ring, or an alkylene group containing a benzene ring,
R ₂ and R ₂ 'may each be the same or different, an alkylene group, an alkylene group containing a cyano group, an alkylene group containing an amide bond, or an alkylene group having both an amide bond and a hydroxyl group. Shall be represented. ) And the general formula

[0018]

[Chemical 10]

(In the formula, R ₃ represents a polyol residue.) At least one polymerizable unsaturated monomer is polymerized in the presence of a compound having a structural unit represented by the formula: (EN) Provided is a novel magnetic paint coated article coated with a novel and useful magnetic paint, which comprises a block copolymer having both a polyurethane segment and a vinyl polymer segment. It is what

Here, so-called polymeric azo initiators each having both a urethane bond and a diazo bond in one molecule described above are represented by, for example, the above-mentioned general formulas [I] and [II], Each of them is a compound having a specific structural unit, but if only representative examples of the polyurethane-type polymer polyazo initiator are exemplified, azobiscyanopropanol, azobiscyano-n-butanol, azobisisobutanol, or Various azobisalkanol compounds such as azobiscyanopentanol; or "VA-080, V
A-082 or VA-086 "(product of Wako Pure Chemical Industries, Ltd.), such as various azoamide polyols, and a compound having at least one diazo bond and at least two hydroxyl groups in one molecule. , A polyisocyanate compound, and those obtained by the reaction of a polyol compound, the molecular weight of the polyurethane-type polymer polyazo initiator is not particularly limited, it is preferable from the use as a magnetic coating, Has a number average molecular weight of 1,500 to 50,000.

That is, if only representative examples of such polyurethane-type polymer polyazo initiators are given, isophorone diisocyanate, methylcyclo-hexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate are used. , 4,
Various diisocyanates such as 4′-methylenebis (cyclohexylisocyanate), 1,3-di (isocyanatomethyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylcyclohexane diisocyanate, tolylene diisocyanate or xylene diisocyanate;

Alternatively, each of these diisocyanates and various polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol or dipentaerythritol, or a functional group capable of reacting with an isocyanate group, for example, , Having a number average molecular weight of about 500 to 1,500,
With various polyisocyanate compounds such as adducts with extremely low molecular weight polyester compounds,

Ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
1,4-butanediol, 1,3-butanediol,
1,6-hexanediol, 3-methyl-1,5-pentadiol, neopentyl glycol, cyclohexanedimethanol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3 -Propanediol, 2-ethyl-1,3-hexanediol, 2,
2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropionate, 12-hydroxystearyl alcohol, polyethylene glycol, polypropylene glycol or polyhexamethylene glycol, or trimethylolethane, trimethylolpropane, Various di- or polyols such as glycerin, pentaerythritol or hydrogenated bisphenol A, further bisphenol A, polyester polyol, etc.,

As described above, it can be obtained by addition condensation reaction of a ternary component with a compound having at least one diazo bond and at least two hydroxyl groups in one molecule.

The number average molecular weight of the above di- or polyol compound is not particularly limited, but from the viewpoint of reactivity and the like, preferably 1,
It is preferably up to 500, more preferably up to 1,000.

Further, to exemplify only the typical polyester polyols mentioned above, various di- or polyol compounds as described above, isophthalic acid, terephthalic acid, (anhydrous) phthalic acid,
Such as (anhydrous) tetrahydrophthalic acid, (anhydrous) hexahydrophthalic acid, trimellitic anhydride, pyromellitic acid, fumaric acid, maleic acid, succinic acid or azopic acid,
Various hydroxyl group-containing polyester resins (including oil-modified types) obtained by dehydration condensation with various di- or polycarboxylic acids (anhydrides) and / or various kinds of ε-caprolactone or valerolactone. Various hydroxyl group-containing polyester resins obtained by ring-opening polymerization of a lactone compound, and the like, all of which are obtained by known and commonly used reaction methods.

In particular, in order to improve the dispersibility of the magnetic recording medium, various carboxyl group-containing diols or carboxyl groups such as dimethylolpropionic acid, sodium dimethylolpropionate or dimethylolpropionic acid-tetramethylammonium salt are used. Acid-base containing diols;

2-sulfonic acid-1,4-butanediol, 1-sulfonic acid-1,4-butanediol, 3-sulfonic acid-2,5-dimethyl-3-hexene-2,5-
Diol, 2-sulfosodium-1,4-butanediol, 1-sulfosodium-1,4-butanediol, 3-sulfosodium-2,5-dimethyl-3-hexene-2,5-diol, 2,5 Various sulphonic acid group-containing diols or sulphonic acid group-containing diols such as disulfopotassium-3,4-hexanediol or 3-sulfopotassium-1,5-pentanediol;

Alternatively, use of various phosphate group-containing diols or phosphate group-containing diols such as 2-phosphate-1,4-butanediol or sodium 2-phosphate-1,4-butanediol. Can be done.

Here, as the method for synthesizing the polymer azo initiator, a method in which the above three components are simultaneously charged and reacted, or an isocyanate group-containing polyurethane intermediate, that is, a so-called urethane is used. There is a method in which a prepolymer is first prepared, and then a compound having at least one diazo bond and at least two hydrous acid in one molecule is reacted with the prepolymer. Is not particularly limited and may be appropriately selected and used.

In the reaction of these di- or polyol compounds with the di- or polyisocyanate compounds, ethylenediamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, bisaminopropylamine are used as chain extenders. Alternatively, various polyamine compounds such as 4-aminomethyl-1,8-diaminooctane may be used,
Of course.

The above-mentioned polymerizable unsaturated monomers are various aromatic vinyl monomers such as styrene, α-methylstyrene, pt-butylstyrene or vinyltoluene; methyl (meth). Acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2- Various hexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, dibromopropyl (meth) acrylate, tribromophenyl (meth) acrylate or alkoxyalkyl (meth) acrylate. (Meta) Acrylate compounds;

Diesters of various unsaturated dicarboxylic acids such as maleic acid, fumaric acid or itaconic acid with monohydric alcohols; vinyl acetate, vinyl benzoate or "Beoba" (vinyl ester manufactured by Shell Co., Netherlands) ) Such as various vinyl esters; "biscoat 8F, 8FM, 17FM, 3F or 3FM" [fluorine-containing acrylic monomer manufactured by Osaka Organic Chemical Co., Ltd.], perfluorocyclohexyl (meth) acrylate, di-
Perfluorocyclohexyl fumarate or N-i-
Propyl perfluorooctane sulfonamide ethyl (meth) acrylate, such as various (per) fluoroalkyl group-containing -vinyl esters, -vinyl ethers,-(meth) acrylates or -unsaturated polycarboxylic acid esters. A fluorine-containing polymerizable compound;

Alternatively, vinyl monomers having no functional group such as olefins such as (meth) acrylonitrile, vinyl chloride, vinylidene chloride, vinyl fluoride or vinylidene fluoride; (meth) acrylamide, dimethyl (meth) acrylamide , Various amide bond-containing vinyl monomers such as N, tert-butyl (meth) acrylamide, N-octyl (meth) acrylamide, diacetone acrylamide, dimethylaminopropyl acrylamide or alkoxylated N-methylol (meth) acrylamides If dialkyl [(meth) acryloyloxyalkyl] phosphates or (meth) acryloyloxyalkyl acid phosphates or dialkyl [(meth) acryloyloxyalkyl] phosphites As initially and (meth) acryloyloxy alkyl acid phosphites,

Various epoxy group-containing vinyl monomers such as the above-mentioned (meth) acryloyloxyalkyl acid phosphates, alkylene oxide adducts of acid phosphites, or glycidyl (meth) acrylate and methylglycidyl (meth) acrylate. And various phosphorous atom-containing vinyl monomers such as ester compounds of phosphoric acid or phosphorous acid or these acid esters, or 3-chloro-2-acidphosphoxypropyl (meth) acrylate; dimethylamino Various dialkylaminoalkyl (meth) acrylates such as ethyl (meth) acrylate or diethylaminoethyl (meth) acrylate;

2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3
-Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di- 2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate, or polypropylene glycol, or
Polyethylene glycol mono (meth) acrylate,
Hydroxyalkyl esters of various α, β-ethylenically unsaturated carboxylic acids or adducts of these with ε-caprolactone, such as “Plaxel FM or FA monomer” [caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.] ;

Various unsaturated mono- or dicarboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid or citraconic acid, and various dicarboxylic acids thereof and monohydric alcohols. And various α, β-ethylenically unsaturated carboxylic acids such as monoesters thereof, or various α, β-ethylenically unsaturated carboxylic acid hydroxyalkyl esters as described above, and maleic acid and succinic acid. , Phthalic acid,
Anhydrous of various polycarboxylic acids such as hexahydrophthalic acid, tetrahydrophthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, "Himimic acid" (product of Hitachi Chemical Co., Ltd.), tetrachlorophthalic acid or dodecynylsuccinic acid. Various unsaturated carboxylic acids such as adducts with substances, "CARDURA E" (glycidyl ester of branched synthetic resin fatty acid manufactured by Shell Co.),
Monoglycidyl esters of various monovalent carboxylic acids such as coconut oil fatty acid glycidyl ester or octyl acid glycidyl ester, or adducts with various monoepoxy compounds such as butyl glycidyl ether, ethylene oxide or propylene oxide, Alternatively, various hydroxyl group-containing monomers such as adducts of these with ε-caprolactone and hydroxy vinyl ethers;

2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3
-Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di- 2-hydroxyethyl fumarate, mono-2-hydroxyethyl-monobutyl fumarate or polyethylene glycol mono (meth)
Various α, β-unsaturated carboxylic acid hydroalkyl esters such as acrylates and maleic acid, succinic acid, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, “hymic acid” , Various carboxyl group-containing monomers, such as adducts of various polycarboxylic acids with anhydrides, such as tetrachlorophthalic acid or dodecynyl succinic acid;

Silicone type such as vinylethoxysilane, α-methacryloxypropyltrimethoxysilane, trimethylsiloxyethyl (meth) acrylate or "KR-215 or X-22-5002" (produced by Shin-Etsu Chemical Co., Ltd.). It refers to monomers and the like.

Here, in order to improve the dispersibility of the magnetic recording medium, various carboxyl group-containing monomers or salts thereof, parastyrene sulfonic acid, 2-acrylamido-2-methylpropane as described above are used. Sulfonic acid, ethyl sulfonate (meth) acrylate or salts thereof, or various phosphoric acid group-containing monomers or salts thereof as described above, such as sulfonic acid group, sulfonate group, carboxyl group, carboxyl group The use of a monomer having at least one group selected from the group consisting of an acid base, a phosphate group, a phosphate group, a phosphite group, a phosphite group, a hypophosphite group and a hypophosphite group, Especially effective.

Further, the salt referred to herein is an alkali metal salt such as potassium or sodium; various monoalkylamines such as trimethylamine, triethylamine, N-methylmorpholine, ammonia, monomethylamine or monobutylamine, and Dialkylamines such as dimethylamine or dibutylamine, various alicyclic amines such as morpholine, amine salts with various aromatic amines such as aniline or toluidine; or tetraalkylammonium It refers to quaternary ammonium salts and the like obtained by reacting a halide or tetraalkylammonium hydroxide.

These base-containing block copolymers are used in the synthesis of the polymer azo initiator by using the base-containing compounds, in the synthesis of the block copolymer by using the base-containing monomer, or in the polymer. It can be obtained by converting the azo initiator or the block copolymer into a base during or after the synthesis, but the method is not particularly limited.

Thus, the polymerization for obtaining the vinyl-based (co) polymer can be carried out by using the above-mentioned respective raw material components by making full use of the well-known and common copolymerization reaction method. Isobutyronitrile (AIBN), benzoyl peroxide (BPO), t-butyl perbenzoate (TBPB), t-butyl hydroperoxide,
It goes without saying that various radical-generating polymerization catalysts such as di-t-butyl peroxide (DTBPO) or cumene hydroperoxide (CHP) may be used alone or in combination of two or more.

Further, in the magnetic coating used in the present invention,
If necessary, the polyurethane that is added and used is
As mentioned above, various diisocyanates or polyisocyanates, and as mentioned above various low-molecular diol compounds or polyester diols, polyester polyols, polyethers such as various oligodiols, oligopolyols, It is obtained by an addition reaction of polymer diols or polymer polyols,

For example, with adipic acid or phthalic acid,
As synthesized from neopentyl glycol etc.,
It is obtained by a reaction of oligopolyesters having a molecular weight of about 600 with tolylene diisocyanate.

The amount used is not particularly limited, but it is usually used in the range of 0 to 500 parts with respect to 100 parts of the block copolymer component. When used, it is particularly preferably 2 from the viewpoint of the balance of physical properties.
Used in the range of 0 to 100 parts.

The magnetic coating material applied to the magnetic coating material-coated article of the present invention can be obtained by using the block copolymer thus obtained, magnetic powder, polyurethane and a coating solvent as essential components. Of course, a curing agent, a dispersant, a lubricant, an abrasive or an antistatic agent may be mixed.

Here, only the representative magnetic powders will be given as examples, and γ-ferrite, cobalt γ-ferrite, barium-ferrite, metallic iron and their alloys (so-called metallic powder), etc. However, if only representative examples of the above coating solvent (coating solvent) are given, various ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone; methanol, ethanol, propanol or butanol Various alcohols such as;

Various esters such as ethyl acetate, butyl acetate or ethylene glycol monoacetate;
Various ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether or dioxane; various aromatic hydrocarbon solvents such as benzene, toluene or xylene; various halogenated hydrocarbons such as methylene chloride, carbon tetrachloride or chloroform , Or dimethylformamide,
Various aprotic polar solvents such as dimethyl sulfoxide, sulfolane, and N-methylpyrrolidone are used, but of course, the solvent used when synthesizing the block copolymer may be used.

The curing agent used if necessary is
Although not particularly limited, polyisocyanate is suitable, and specifically, "Bernock D-750".
Or "Chris Bonn NX" [above, product of Dainippon Ink and Chemicals, Inc.], "Desmodur L" [product of Sumitomo Bayer Co., Ltd.], "Coronate L" [product of Nippon Polyurethane Co., Ltd.], "Takenate D-" 102 "[Takeda Pharmaceutical Co., Ltd. product]," Barnock D-950 "[Dainippon Ink and Chemicals Co., Ltd. product]," Desmodur
R "," Desmodur RF "[above, products of Sumitomo Bayer Co., Ltd.], various polyisocyanate resins (isocyanate prepolymers), and various diisocyanate compounds described above are particularly representative. As.

The ratio of the block copolymer to the polyisocyanate described above is not particularly limited, but preferably 100 parts by weight of the block copolymer is mixed with the polyisocyanate as listed above. It is used in an amount of 0 to 200 parts by weight, and when used, it is particularly preferable to add it in a proportion of 3 to 40 parts by weight and to cure it, so that the mechanical strength of the urethane resin after curing is usually
Abrasion resistance, resistance to moist heat, solvent resistance, and adhesion to a substrate are improved.

Further, only representative representative examples of the dispersant include caprylic acid, capric acid, lauric acid, myristic acid, stearic acid, oleic acid, elaidic acid, linoleic acid or linolenic acid. Such fatty acids having 12 to 18 carbon atoms, metal soaps made of alkali metals or alkaline earth metals of such fatty acids, or lecithin.

Further, silicone oil, carbon black, graphite, or the like is given as a representative of the above lubricants. Furthermore, the abrasive may be one that is commonly used, and specifically, fused alumina, silicon carbide chromium oxide, diamond, artificial diamond, garnet, etc. are particularly representative. As.

Then, only representative examples of the above-mentioned antistatic agents are listed, and various conductive powders such as graphite or carbon black; various natural surfactants such as saponin; Various nonionic surfactants such as alkylene oxide type, glycerin type or glycidol type; various cationic surfactants such as higher alkyl amines, quaternary ammonium salts or sulfoniums; carboxylic acids, sulfonic acids, Various anionic surfactants containing an acidic group such as phosphoric acid, a sulfuric acid ester group or a phosphoric acid ester group; or various amphoteric surfactants such as amino acids, aminosulfonic acids, sulfuric acid or phosphoric acid esters of amino alcohols, etc. Is.

For the block copolymer,
Usually used vinyl chloride vinyl acetate copolymer,
It is also possible to use in combination with commercially available products such as fibrin resin, vinyl chloride polymer, polyvinyl butyral resin, thermoplastic polyester resin, vinyl chloride vinyl propionate copolymer, epoxy resin or phenoxy resin. is there.

The coated article of the present invention is not particularly limited, but polyethylene terephthalate, polyethylene-2,
Various polyesters such as 6-naphthalate; Various polyolefins such as polypropylene; Various cellulose derivatives such as cellulose triacetate or cellulose diacetate; Various such as polycarbonate, polyimide, polyamideimide, polystyrene or acrylic resin, etc. Resins of Cu; Al or Zn
Various kinds of metals, such as glass, porcelain or pottery, various kinds of ceramics, paper, etc.
The form used is not particularly limited, but typically, it is used in the form of tape, sheet, card, disk or drum.

The coating method for the article to be coated is not particularly limited, but may be air doctor coating, bleed coating, air knife coating, squeeze coating,
Impregnation coats, reverse roll coats, transfer roll coats, gravure coats, kiss coats, cast coats or spray coats are particularly representative.

The block copolymer obtained as described above, which is used in the present invention, is particularly excellent in various physical properties such as pigment dispersibility, wet heat resistance, abrasion resistance, fluidity and permanent elongation. Therefore, it can be used for applications other than the binder of the magnetic recording medium.

For example, various printing inks, magnetic rubber,
Various paints, conductive resins, adhesives and the like are mentioned as the most important ones.

[0060]

EXAMPLES Next, the present invention will be described more specifically with reference to Reference Examples, Examples and Comparative Examples. In the following, all parts and percentages are based on weight unless otherwise specified. .

Reference Example 1 (Preparation Example of Polymer Azo Initiator) In a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, 1,500 parts of methyl ethyl ketone, 58 parts of azobiscyanopropanol and di- 0.2 part of n-butyltin dilaurate was charged, and while stirring and cooling with ice, 546 parts of hexamethylene diisocyanate was added to 2 parts.
After dropping over a period of time, the temperature was raised to 20 ° C., the temperature was maintained for 2 hours to continue the reaction, and then ice cooling was performed again.

Then, dipropylene glycol 396
Then, the temperature was raised to 30 ° C., and the temperature was maintained for 10 hours to continue the reaction. The polyurethane polymer azo initiator obtained here is a gel permeation
The number average molecular weight in terms of polystyrene measured by chromatography (GPC) is 20,500 at 25 ° C.
Has a Gardner viscosity of Z ₁ and a nonvolatile content of 4
It was 0%.

To determine other characteristic values for this polymeric azo initiator, 5 parts hydroquinone and 20 parts n-butanol were each added to 20 parts of the initiator at 100 ° C. Heating was continued for 10 hours at to decompose the initiator.

The number average molecular weight of the decomposed product obtained here was 3,200, and it was found that the objective polymer azo initiator had an average of 6.4 diazo bonds in one molecule.

Reference Example 2 (same as above) In a container similar to Reference Example 1, 1,0 of methyl ethyl ketone was added.
After charging 00 parts, 500 parts of n-methylpyrrolidone, 366 parts of dipropylene glycol, 0.1 part of dimethylolpropionic acid and di-n-butyltin dilaurate, after heating to 80 ° C. under stirring, 546 parts of hexamethylene diisocyanate was added dropwise over 2 hours, and the reaction was continued at the same temperature for 5 hours.

The number average molecular weight in terms of polystyrene measured by (GPC) of the isocyanate group-containing polyurethane thus obtained was 3,700. However, after being subjected to a treatment of reacting an isocyanate group with diethylamine, it is provided for measurement by GPC.

Then, 2,442 parts of this isocyanate group-containing polyurethane was charged into a reaction vessel similar to that described above, and 58 parts of azobisisopropanol was added to the polyurethane under ice cooling. 30 ° C
The temperature was raised to 10 ° C. and the reaction was carried out at the same temperature for 10 hours.

The number average molecular weights of the polyurethane polymer azo initiator and the decomposed product thus obtained were 1 and 2, respectively.
It is known to be a polyurethane polymeric azo initiator having an average of 6.0 diazo bonds in one molecule. The target initiator solution had a nonvolatile content of 40% and a Gardner viscosity of YZ at 25 ° C.

Reference Example 3 (Same as above) A reaction vessel equipped with a thermometer, a stirrer and an air condenser was charged with 614 parts of adipic acid, 438 parts of neopentyl glycol and 698 parts of isophthalic acid and heated at 140 ° C. for 1 hour. After reacting for 2 hours, the temperature is gradually raised to 220 ° C. over 2 hours, and the reaction is performed at the same temperature for 6 hours. The acid value is 2, the hydroxyl value is 78, and the number average molecular weight is 1 , 400 polyester resin was obtained.

Next, in a reaction vessel similar to that of Reference Example 1, 797 parts of the above polyester resin, 55 parts of azobiscyanopropanol, and 0. 0 of di-n-butyltin dilaurate were added.
After charging 2 parts and 1,500 parts of methyl ethyl ketone, 14 parts of tolylene diisocyanate was added under ice cooling.
8 parts was added dropwise over 2 hours. 30 ° C even after dropping
When the temperature was raised to, and kept at the same temperature for 10 hours to continue the reaction, the number average molecular weight was 22,000.
Thus, a solution of the target polyurethane polymer azo initiator having a viscosity of W-X and a nonvolatile content of 40% was obtained.

To 20 parts of this polyurethane polymer azo initiator, 5 parts of hydroquinone and 20 parts of n-butanol were added, respectively, and the mixture was heated at 100 ° C. for 10 hours to obtain high When the molecular azo initiator is decomposed, the number average molecular weight of this decomposed product is 3,300, and therefore, this polyurethane polymer azo initiator has an average of 6.7 diazo bonds in one molecule. It has been found.

[0072]

[Table 1]

<< Footnote in Table 1 >> The "amount of diazo groups in one molecule" in the table means the number of the diazo groups.

Reference Examples 4 to 5 (same as above) Under the conditions as shown in Table 1, the solvent, the azoalkanol compound, the polyol compound and the polyisocyanate compound were changed to those shown in Table 1, and the conditions shown in the same table were used. Various target polyurethane polymer azo initiators were obtained in the same manner as in Reference Example 1 except that the reaction was performed.

The values of various properties of each polymer azo initiator are as shown in the same table.

[0076]

[Table 2]

Reference Example 6 A four-necked flask equipped with a thermometer, a stirrer and a reflux condenser was charged with 150 parts of toluene and 5 parts of dimethylformamide.
Charged 0 parts and 500 parts of cyclohexanone to 80
The temperature was raised to 180 ° C., and 180 parts of styrene, 550 parts of methyl methacrylate, 50 parts of 2-hydroxyethyl methacrylate, 20 parts of 2-acrylamido-2-methylpropanesulfonic acid, and Reference Example 1 were added. A mixed solution containing 500 parts of the obtained polyurethane polymer azo initiator,
It was allowed to drip over 4 hours.

After the dropping, the number average molecular weight was 2 when the polymerization reaction was continued by keeping the same temperature for 10 hours.
A solution having a polyurethane-acrylic resin block copolymer of 2,000 with a nonvolatile content of 50% and a Gardner viscosity of Y at 25 ° C. was obtained.

[0079]

[Table 3]

[0080]

[Table 4]

<< Footnote in Table 2 >>"Number average molecular weight" in the table
Means 100 times (× 10 ² ).

Reference Examples 7 to 12 Polymerization solvents as shown in Table 2 (1) and (2),
Various block copolymers and various block copolymers were prepared in the same manner as in Reference Example 1 except that an initiator and a polymerizable unsaturated bond-containing monomer were used and the polymerization conditions were changed as shown in the same table. A random copolymer was obtained.

[0083]

[Table 5]

[0084]

[Table 6]

Reference Example 13 A reaction vessel equipped with a thermometer, a stirrer and an air condenser was charged with 1,218 parts of adipic acid and 720 of 1,4-butylene glycol and reacted at 140 ° C. for 1 hour. It took 2 hours to gradually raise the temperature to 220 ° C., react at the same temperature for 6 hours, and the acid value was 2,
In addition, a polyester resin having a hydroxyl value of 59 was obtained.

Then, 92 of the obtained polyester resin was used.
1 part, 6000 parts of cyclohexanone, 400 parts of dimethylformamide and 79 parts of tolylene diisocyanate were charged, and the reaction was continued at 80 ° C. for 10 hours. The number average molecular weight of the obtained polyurethane resin is 30,000.
Met.

Reference Example 14 In a reaction vessel similar to that of Reference Example 13, 522 adipic acid was added.
Part, 498 parts of isophthalic acid, 664 of terephthalic acid
Part, 186 parts of ethylene glycol, 416 parts of neopentyl glycol and 360 of 1,4-butylene glycol were charged and allowed to react at 140 ° C. for 1 hour, and then gradually heated to 220 ° C. over 2 hours. Then, the reaction was carried out at the same temperature for 6 hours to obtain a polyester resin having an acid value of 3 and a hydroxyl value of 45.

Then, 939 of this polyester resin was used.
Parts, 600 parts of methyl ethyl ketone, 400 parts of dimethylformamide and 61 parts of tolylene diisocyanate.
Parts were charged and the reaction was continued at 80 ° C. for 10 hours. The number average molecular weight of the obtained polyurethane resin was 31,500.

Example 1 100 parts of the block copolymer obtained in Reference Example 6, 738 parts of methyl ethyl ketone, and 2 parts of Fe--Ni alloy magnetic powder.
A mixture of 50 parts, 8.6 parts of carbon black and 3.5 parts of a lubricant was kneaded in a ball mill for 48 hours and then "Bernock D-750" [manufactured by Dainippon Ink and Chemicals, Inc.]. , Low molecular weight polyisocyanate]
4.3 parts was added, and the mixture was kneaded for 1 hour, coated on a polyethylene terephthalate substrate film having a thickness of 10 microns (μm) so that the thickness after drying was 8 μm, and dried, It was calendered and cut into a predetermined width to produce a magnetic recording tape.

Then, the obtained magnetic tape was subjected to the following tests to evaluate its performance.

[Gloss Test of Magnetic Tape] The magnetic surface of each magnetic tape before calendering was measured with a digital variable angle gloss meter at an incident angle of 45 degrees and a reflection angle of 45 degrees.

[Moisture and Heat Resistance Durability Test of Magnetic Tape] Each of the obtained magnetic tapes was tested at 70 ° C. and a relative humidity of 95%.
Under these conditions, the sample was stored for 2 weeks, left at room temperature for 24 hours, and then subjected to a running test with a video tape recorder for evaluation. ○: No problem in repeated running △: Slight uneven running ×: Stopping running due to severe tape adhesion

[Abrasion resistance test of magnetic tape] The magnetic surface of the obtained magnetic tape was measured using a Taber abrasion tester.
The number of times until the magnetic layer came off was measured.

[Surface smoothness of magnetic tape] It was visually determined.

[0095]

[Table 7]

<< Footnotes in Table 3 >>"VAGH" --- Vinyl chloride-vinyl acetate copolymer "Bernock D-750" manufactured by Union Carbide Co., Ltd., manufactured by Dainippon Ink and Chemicals, Inc. Polyisocyanate resin

Examples 2 to 7 and Comparative Examples 1 and 2 Under the compounding conditions shown in Table 3, magnetic tapes were prepared and evaluated in the same manner as in Example 1.

[0098]

[Table 8]

[0099]

[Table 9]

[0100]

As shown in Table 3, the magnetic coating material of the present invention containing the block copolymer and the magnetic powder as essential components has good magnetic powder dispersibility and surface smoothness of the magnetic recording medium. It is possible to greatly improve durability, abrasion resistance and the like, and to provide a magnetic paint coated article having extremely high practicality.

Claims (10)

[Claims] 1. A magnetic paint-coated article coated with a magnetic paint containing, as essential components, a block copolymer having both a polyurethane segment and a vinyl polymer segment, and a magnetic powder. 2. A magnetic paint-coated article coated with a magnetic paint containing, as essential components, a block copolymer having both a polyurethane segment and a vinyl polymer segment, magnetic powder, and polyurethane. 3. A magnetic paint-coated article coated with a magnetic paint containing, as essential components, a block copolymer having both a polyurethane segment and a vinyl polymer segment, magnetic powder, and polyisocyanate. 4. A magnetic paint-coated article coated with a magnetic paint containing, as essential components, a block copolymer having both a polyurethane segment and a vinyl polymer segment, magnetic powder, polyurethane, and polyisocyanate. 5. The above block copolymer is a sulfonate group, a sulfonate group, a carboxyl group, a carboxylate group, a phosphate group, a phosphate group, a phosphite group, a phosphite group or a hypophosphorous acid. A magnetic paint-coated article according to any one of claims 1 to 4, which has at least one group selected from the group consisting of a group and a hypophosphite group. 6. The block copolymer described above is a sulfonate group, a carboxylate group, a phosphate group, a phosphite group or a hypophosphite group, and an alkali metal salt, an amine salt or The magnetic paint-coated article according to any one of claims 1 to 5, which has at least one salt selected from the group consisting of quaternary ammonium salts. 7. The block copolymer having both the polyurethane segment and the vinyl polymer segment described above, having at least one block copolymer in one molecule, having the general formula: (In the formula, R ₁ is an alkylene group, a cyclic alkylene group, an alkylene group having an ester group, a benzene ring, or an alkylene group containing a benzene ring, and R ₂ and R ₂ 'are the same. , Which may be different, represent an alkylene group, an alkylene group containing a cyano group, an alkylene group containing an amide bond, or an alkylene group having both an amide bond and a hydroxyl group.), General formula: (Provided that R ₃ in the formula represents a polyol residue.) Is obtained by polymerizing at least one polymerizable unsaturated monomer in the presence of a compound having a structural unit represented by The magnetic paint-coated article according to any one of claims 1 to 6, which is used. 8. The block copolymer having both the polyurethane segment and the vinyl polymer segment described above, wherein at least one block copolymer is represented by the general formula: embedded image (In the formula, R ₁ is an alkylene group, a cyclic alkylene group, an alkylene group having an ester group, a benzene ring, or an alkylene group containing a benzene ring, and R ₂ and R ₂ 'are the same. , Which may be different, represent an alkylene group, an alkylene group containing a cyano group, an alkylene group containing an amide bond, or an alkylene group having both an amide bond and a hydroxyl group.), General formula (Provided that R ₃ in the formula represents a polyol residue) and has a structural unit of 1,500
~ 2 of compounds having a number average molecular weight of 50,000
7. The composition according to claim 1, which is obtained by polymerizing 98 to 5 parts by weight of at least one polymerizable unsaturated monomer in the presence of 95 parts by weight. Magnetic paint coated articles. 9. At least one molecule in said one molecule,
General formula: (In the formula, R ₁ is an alkylene group, a cyclic alkylene group, an alkylene group having an ester group, a benzene ring, or an alkylene group containing a benzene ring, and R ₂ and R ₂ 'are the same. , Which may be different, represent an alkylene group, an alkylene group containing a cyano group, an alkylene group containing an amide bond, or an alkylene group having both an amide bond and a hydroxyl group.), General formula: (Provided that R ₃ in the formula represents a polyol residue.) Is a compound having a structural unit represented by the following formula: a sulfonate group, a sulfonate group, a carboxyl group, a carboxylate group, a phosphate group, and a phosphorus group. 9. The magnetic material according to claim 7, which has at least one group selected from the group consisting of an acid base, a phosphite group, a phosphite group, a hypophosphite group and a hypophosphite group. Painted articles. 10. The at least one polymerizable unsaturated monomer to be polymerized is a sulfonate group, a sulfonate group, a carboxyl group, a carboxylate group, a phosphate group, a phosphate group, or a phosphorous acid. At least one selected from the group consisting of a group, a phosphite group, a hypophosphite group, and a hypophosphite group.
The magnetic paint-coated article according to claim 7 or 8, which contains a polymerizable unsaturated monomer having a seed group as an essential component.