JPS6020315A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a recording medium having a magnetic layer in which the dispersibility of magnetic articles is excellent and which is highly strong by using a polyester resin or polyurethane resin with which an alkali metal salt of a compd. having a specific group including P is brought into reaction as a binder for ferromagnetic powder. CONSTITUTION:A resin contg. 0.02-2wt% P formed by bringing the compd. expressed by the formula II (R2 is bivalent or trivalent hydrocarbon group of C1-6, R3 is H, the same group as R1 or alkali metal, M is an alkali metal, n is 1 or 2) having the group expressed by the formula I (R1 is a hydrocarbon group of C1-12 or a hydrocarbon group of C1-12 contg. an ester formable functional group) into reaction with a polyester resin or polyurethane resin is used as a binder. A magnetic layer with ferromagnetic material powder dispersed into such binder is formed on a nonmagnetic base by a coating method. The magnetic recording medium having the magnetic layer which is strong in the adhesion power to the base and has good smoothness and having a high squareness ratio is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a magnetic recording medium with excellent magnetic properties and mechanical q1 properties.

General-purpose magnetic tape is made by dispersing gold 11-shaped magnetic particles with a long axis of 1 μm or less in a binder solution with appropriate additives (dispersant, iN?f') agent, antistatic agent, etc.) to create a magnetic coating. , is made by coating this on polyethylene terephthalate film.

Magnetic recording media are required to have high magnetic recording density and high reproduction output, and for this purpose, it is necessary to highly fill and highly align magnetic particles with high coercive force. In order to achieve high filling and high orientation, the magnetic particles must be dispersed down to the primary particles. The influence of a single binder 11i4 on the dispersion of magnetic particles is large, and no matter how efficient a dispersion machine is used, if the dispersion ability of the binder is low, the magnetic particles will not be dispersed in the paint. In addition, magnetic particles with high coercive force have been developed, but as the coercive force increases, the magnetic particles become more difficult to disperse.

Conventionally, as binders for magnetic paints, vinyl chloride/vinyl acetate JQ combination, vinyl chloride/i! 11. Acid vinyl-vinyl alcohol copolymer, vinyl chloride-vinylidene chloride copolymer, thermo-movable polyurethane resin, thermosetting polyurethane resin, polyester resin, acrylonitrile-butylene J"M<4", nitro Cellulose, cellulose acetabilate, epoxy resin, acrylic resin, etc. have been used, but
Videotave? In particular, it appears that the magnetic properties are not sufficient for applications that require high performance, such as 1J, 1,000Ml'Rf'1 tapes. In order to improve magnetic properties, it is known that an active agent is used as a dispersant, but the presence of a surfactant (low molecular weight in the magnetic phase 11Q) causes a decrease in physical properties over time. 0Magnetic tape does not have excellent magnetic properties, but also has excellent mechanical properties such as wear resistance, soil properties, running properties, flexibility, adhesion to the support, and curvature. No.Polyester fJ IIF+, polyurethane tree 1
[Magnetic tape using i7 as a binder is 1゛,? Publication 44-17947.9″q Publication 44-1822
2, Special Publication No. 45-24900, Special Publication No. 45-231)
OO, % Publication 45-24902, Special Publication 49-481
26, Special Publication No. 48731611, Special Publication No. 4 B-316
10, Special Number [1fl 42-15432, Special Publication 1977-
As shown in 6522, it has mechanical properties and is useful as a magnetic tape binder.

The present inventors have discovered that the dispersibility of magnetic particles can be dramatically improved by introducing gold-14 sulfonic acid salt into polyester resin or polyurethane resin, and have already proposed (
JP-A-54-28603, JP-A-54-1avso3)
. The effect of metal salts of sulfonic acids is due to their hydrophilicity, and similar effects can be expected from gold hh salts of phosphorus compounds of phosphinic acids and phosphones ff2'4. However, metal salts of phosphorous compounds such as phosphinic acid and phosphonic acid (A2e) may cause deactivation of the catalyst during the production of polyester resin, may cause ether bonds to be formed, resulting in a decrease in the physical properties of the resulting polymer, or may have different polarity. Therefore, they may separate without reacting uniformly. Even in polyurethane resins, metal salts of phosphorus compounds such as phosphinic acid and phosphonic acid are highly inorganic, so they may react in a general-purpose solvent or without a solvent, causing them to separate into the resin. , it was impossible to introduce this hydrophilic group.

In view of the above-mentioned circumstances, the present invention 43 etc. aims to improve the dispersibility of magnetic particles while maintaining the mechanical properties of polyester 4M resin and polyurethane (resin 43). As a result of (curse 1'l), if we do not use an alkali gold kl salt of a phosphorus compound with a constant of 14゛, the price of polyester wood 11t7s polyurethane persimmon 1 goods > JL
It has been found that the L1: &J structure has the ability (1), and that the target nQ property of the magnetic particles can be improved by 70%.

That is, the present invention provides a magnetic recording material 4 in which a magnetic phase agent in which ferromagnetic powder is dispersed in a binder is coated on a non-magnetic support material 2.
Fl! ? , in the body, the following formula (1
) Alkali gold jJs of a phosphorus compound having a group represented by
jlX reacted with t→polynisder resin and Ql/
I: A magnetic recording medium characterized by using bamboo polyurethane horizontal 1117.

R.

(In the formula, R□ represents a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 12 carbon atoms containing an ester-forming functional group.) By using a polyester resin and/or polyurethane resin reacted with an alkali metal salt of a phosphorus compound having a group as a binder, the dispersibility of magnetic particles is improved, and excellent magnetic q゛, r properties and mechanical properties are achieved. A magnetic recording medium is obtained.

The carboxylic acid component of the polyester resin used in the present invention includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalic acid, p-oxybenzene, yamazoic acid, p-(hydroxy Before aromatic oxycarboxylic acid such as ethoxy) benzoic acid, amber W
', aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacyl dicarboxylic acid, dodecane dicarboxylic acid, tri- and tri-tracarboxylic acids such as rimesic acid and pyromellitic acid can be used. Particularly preferred are terephthalic acid, isophthalic acid, adipic acid, and henanoccinic acid.

The glycol components of the polyester resin include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1195-bentanediol, 1,6-hexanediol, 1-neopentyl glycol, diethylene glycol, dipropylene glycol, 2.2.4-Trimethyl-1,3-bentanediol, 1,4-cyclohexanedimethanol, ethylene oxide and propylene oxide additives of bisphenol A, ice-formed bisphenol A, ethylene oxide and propylene Okizaiduizukamono,
polyethylene glycol, polypropylene glycol,
Examples include polytetramethylene glycol. Also trimethylolethane, trimethylolethane, glycerin,
Tri- and tetofols such as penquerythritol (II) may also be used.

The polyester tttJ resin used in the present invention has a viscosity of 0, 3ttt/9 in order to obtain mechanical properties.
The polyurethane resin used in the present invention is obtained by the reaction of a polyhydroxy compound and a polyisocyanate, and 1 part or all of the polyhydroxy compound is preferably 79 or more. It is a polyester polyol made by reacting an alkali metal salt of a phosphorus compound having a group represented by the formula, and this polyester polyol has a molecular weight of 500 to 10.
．． 000 is preferable. In addition, polyhydroxy compounds that do not contain phosphorus, such as ordinary polyester polyols, polyether polyols, acrylic polyols, castor oil derivatives, tall oil LA river medicinal compounds, and their low hydrous acid group compounds can be used in combination. Good too. In addition, when producing the polyurethane resin of the present invention, negative
As an extender, it is preferable to use one or more known compounds such as glycols, diamines, alcohols, etc. Among them, glycols are particularly preferred. Examples of polyisocyanates include 2.4-) lylene diisocyanate-ig+6-) lylene diisocyanate, p-phenylene diisocyanate, Shifue=v methane diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate 1 tetramethylene diisocyanate, 3.3 '-dimethoxy-4,4'-biphenylene diisocyanate, 2,4-naphthalene diisocyanate, 13.3'-dimethyl-442-biphenylene diisocyanate, 4,4'-"/"phenylene diisocyanate, 4,4'-diisocyanate-diphenyl ether, 1,5-naphthalene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 1,3-diisocyanate methylcyclohexane,
1.4-diisocyanatemethylcyclohexane, 4.
4'-diisocyanate dicyclohexane, 4.4'-
Examples include diisocyanate dicyclohexylmethane, isophorine diisocyanate, etc., but if necessary, lJ2,
4. 4'-triisocyanate diphgonyl, benzene triisocyanate, etc. can also be used in small amounts.

A polyurethane resin can be prepared by reacting a polyhydroxy compound and a polyisocyanate in a solvent or a hot solvent by a known method, but the desirable blending ratio is p;=0.5 to 2/l. The resulting polyurethane ((υ fat has a molecular weight of 8,000 to ioo,
It is desirable that it be ooo.

To prevent gelation during the urethane reaction, it is preferable to use an acid such as butadiene sulfonic acid, inorganic acid, oxynan, paratoluene sulfonic acid, etc.

Polyester resin and polyurethane resin used in the present invention! t=? The alkali gold h's salt of a specific phosphorus compound that is characterized is one having a group represented by the formula (1) in 1]1, and an example thereof is a compound represented by the following formula (It).

(In the formula, R1 is a hydrocarbon group of carbon atoms K 1 '' l 2 or a carbon atom number of 1 to 12 containing an ester-forming functional group)
hydrocarbon group. R2 is divalent or trivalent having 1 to 6 carbon atoms
valent hydrocarbon group. R3 is a hydrogen atom, having 1 to 12 carbon atoms
a hydrocarbon group, one IA hydrocarbon group having 1 to 12 carbon atoms having an ester-forming functional group, or one alkali gold atom. M is alkali gold! +j J Hayako On indicates a 4% number of 1 or 2. ) Substantially 2-carboxyethylmethylphosphine EI'S, 2-carboxyethylphenylphosphinic acid, 4-carboxyphenylphosphine lf,
2v3-dicarbogibropylmethylphosphine,
and alkali gold 14 salts of these alcohol, phenol or glycol esters.

The 4:4 formula of representative examples of these compounds is shown below.○0 CI (2000CH3 As the alkali Kanagawa atom, in addition to sodium salt, potassium salt and 1 lithium salt are used.

When producing a polyester resin, an alkali metal salt of a phosphorus compound having a group represented by the above formula (1) is added at any stage W? before the completion of polymerization of the polyester. From the operational point of view during production, it is preferable to add the compound at a stage after the ester cross-fertilization reaction or after the esterification reaction.

It is appropriate to use the alkali metal salt of a phosphorus compound having a group represented by the above general formula (1) so that it is contained in the polyester resin or polyurethane resin in an amount of 0.02% to 2% by weight as phosphorus atoms, If it is smaller than the above range, the dispersibility for magnetic particles will decrease, while if it is larger than the above range 11, there will be an increase in hygroscopicity, a decrease in physical properties, a decrease in density X1 properties for polyester films, etc., and the practicality will be reduced. It becomes less.

In the present invention, in addition to polyester resin and polyurethane resin reacted with an alkali metal salt of a phosphorus compound having a group represented by the general formula (+), magnetic tape has excellent flexibility, heat resistance, and cold resistance. It is desirable to add other compatible fats and/or to mix a compound that reacts with the polyurethane resin to crosslink the polyester resin and the polyurethane resin for the purpose of improving wear resistance and abrasion resistance. Examples of resins that are compatible with polyester resins and polyurethane resins used in the invention include vinyl chloride resins, polyester resins, cellulose resins, etc. On the other hand, examples of compounds that crosslink with polyester resins and polyurethane resins include epoxy resins, Examples include isocyanate compounds, melamine resins, urea resins, polyol compounds, etc. Among these, isocyanate compounds are particularly preferred.

The ferromagnetic particles used in the present invention include 1-F
e201, 1-Fe, mixed crystal of o3 and Fe3O4,
Orb, Cobalt ferrite 1 Cobalt adsorbed iron oxide, Fe-Co.

Ferromagnetic alloy powders such as Fe-0o-Ns@ can be arranged.

The magnetic recording medium of the present invention may optionally contain a plasticizer such as dibutyl 7-thalerate, triphenyl phosphate, dioctyl sulfonodium tuccinate, t-butylphenol-polyethylene ether, ethylnaphthalene-
It is also possible to add inhibitors such as sodium sulfonate, dilauryl succinate, stearin r·> jJli ship, soybean oil lecithin, silicone oil.

The present invention will be basically explained below using examples. In the examples, the "Sakae" section refers to the "Shigeshu section" on the left.

For sale, the original adhesive ηop/c Ce1l/9) was prepared by dissolving polyester resin and Boliurethane resin 0.109 in phenol/tetrachloroethane (6/4) 25az,
Measured at 0°C.

Example of production of polyester resin Thermometer, JFf stirrer, 1 l/l autoclave, dimethyl terephthalate (4857 fli), dimethyl isophthalate (175 i5), 409 parts of ethylene glycol, 458 parts of neopentyl glycol, and tetrabutoxy titanate). Prepare 0.68 parts/7.150~
Heating at 230°C for 120 minutes and 114J produces ester 9. Then, 219 parts of adihin resistance and the above phosphorus compound (J
) 3e part was charged and the reaction was further carried out at 220-230°C for 1 hour.Then, the reaction system was heated to 270°C for 30 minutes, the pressure on the thread was gradually reduced, and after 45 minutes, the temperature was 0.1-0.
2 llIm H9, and the reaction was continued under these conditions for an additional 60 minutes. ? iI The resulting polyester resin χ had a tC original viscosity of 0.65 and a phosphatide content of 90 ppm. Polyester resins obtained by the same manufacturing method are shown in Table 1.

The resin composition was analyzed by NMR. No increase in viscosity was observed during polymerization for Polynisder Resin G and Polynisdel Resin G in Table 1. In addition, the polyester (Mf fat H) became granular and completely separated from the resin. Example of producing polyurethane resin: 170 parts of toluene, 170 parts of methyl ethyl ketone, 170 parts of methyl ethyl ketone, 1 has the same composition as polyester resin A, but the molecule is ki g.
, OOo polyester resin A'lo.

1 part, 10 parts of neopentyl glycol, and 0.01 part of p-)luenesulfonic acid as a gelling inhibitor) After dissolving 1 diphenylmethane diisocyanate, 35 parts. '5 parts and 0.05 parts of dibutyl silk dilaurate%7
61F9 jfJ was reacted at 0 to 80"Q to prepare a 1M polyurethane solution with a solid content concentration of 30%.The original viscosity of 77 parts of polyurethane resin 1 from which the solvent was evaporated from the reaction solution was 0.7.
B,! The carbon content was 0.19%.

Polyurethane resins shown in Table 2 were prepared using the same method.
I got ■. However, with polyurethane W resin (1), the sodium salt of the phosphorus compound precipitated, and a uniform resin III could not be obtained.

Examples 1 to 7, Comparative Examples 1 to 5 Magnetic powder (cobalt treated γ-F (1203) ao
Part Polyester Resin A Solution 50 parts (Solid 9 min.A 30%, dissolved ethyl ethyl ketone/toluene - 1/l] IJff ratio) Incyanate compound 2 parts Methyl ethyl ketone 50 parts Toluene 50 parts Methyl Isobutyl ketone 26 parts After mixing the above composition in a ball mill for 24 hours, this magnetic paint was applied onto a 251 t polyethylene terephthalate film to a dry thickness of 61 parts m, and blown for 0.05 seconds. , perform magnetic field orientation treatment in the 1-mist direction of the film using a DC magnetic field of 2,500 Gauss, 10
After drying with hot air for 1 minute at 0°C, calendering was performed. Obtained tape Br/Bm (square ratio) (i
(1 was 0.89. Next, magnetic coating IP'J ir+
After applying cellophane tape of city 11x to +, ('O
When the tape was removed, mosquitoes did not peel off the magnetic coating compared to the polyester film, and the adhesion was good.

Polyester 4iI or polyurethane (fat methylethylton/toluene) shown in Tables 1 and 2
A magnetizable layer was formed on a polyethylene terephthalate film by the same method using a 30% solution of 1/1 weight ratio). The measurement results of each magnetization plane hB B'i are shown in Table 3.

Margin below

Claims (3)

[Claims] (1) In a magnetic recording medium in which a magnetic material in which ferromagnetic powder is dispersed in a binder is coated on a non-magnetic support, 1) a phosphorus compound having a group represented by the following formula (1) as the binder; 1. A magnetic recording medium characterized by using a polynisder resin and/or a polyurethane resin obtained by reacting an alkali metal salt of f. R1 (In the formula, R1 represents a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 12 carbon atoms containing an ester-forming functional group.) (2) The magnetic recording medium according to Patent d Blue Water Scope, Item 1, wherein the alkali metal salt of a phosphorus compound having a group represented by formula (1) is a compound represented by formula (n) below. (In the formula, R1 is a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 12 carbon atoms containing an ester-forming functional group. R2 is a divalent or trivalent hydrocarbon group having 1 to 6 carbon atoms. Hydrocarbon group. R3 is 5 hydrogen atoms and 1 to 2 hydrogen atoms.
12 softening hydrogen groups, a hydrocarbon group having 1 to 12 carbon atoms, or an alkali metal atom having an ester-forming functional group. M is an alkali metal atom. n represents an integer of 1 or 2. ) (3) Reacting an alkali metal salt of a phosphorus compound having a compound represented by the above formula (1) so that the phosphorus content in one polynisder resin or polyurethane resin is 0.02 to double fit%. The magnetic recording medium according to claim 11, characterized in that the magnetic recording medium is made of polyester (11t7) and/or polyurethane resin.