KR840001844B1 - Process for preparing megnetic metal and alloy - Google Patents

Abstract

Magnetic metal-alloy pigment is prepared by coating 0.2-30 wt.% of ortho-ester silicate(I), its hydrolysis product, or a condensation product on magnetic metal or its alloy. The chemical formula of (I) is (RO)nSi(OR')4-n, where R = oxygen bridge, C1-C20 alkyl, cycloalkyl, alkenyl, aryl or aralkyl gp.; R1 = C1-C4 alkyl gp.; and n = 0-4. Corrosion resistance of the pigment is increased by adding a corrosion inhibitor such as a higher amine, aldehyde, alcohol, ketone, etc.

Description

Manufacturing method of magnetic metal pigment and alloy pigment

The present invention relates to a non-ignitable magnetic metal pigment containing a siliceous ester-based material on its surface and a method for producing the alloy pigment.

As the need for high quality magnetic recording materials increases, magnetic metals and alloy pigments based on iron, cobalt and / or nickel have recently been developed. This differs from conventional iron oxide and chromium dioxide pigments in that it is a significantly larger energy product (B × H-value), and also produces a magnetic recording medium with excellent memory density and at the same time reduces the amount of magnetic active material required. Let's do it.

One of the reasons why the pigment has not been successful in the field of marketing so far is due to its high chemical reactivity. Pigment-sized metal particles spontaneously ignite because they have a high affinity for oxygen and are converted to metal oxides upon sudden exposure to air at room temperature. See Rompps Chemie-Lexikon, 7th Edition, Franckh'sche Verlagshandlung, Stuttgart 1975, page 2852. In other words, these metal particles are flammable and should always be handled, transported and processed under inert conditions.

In the past, many attempts have been made to provide a suitable method for ameliorating the above disadvantages. The flammability of the metal particles can be removed by surface oxidation, but by doing so

Attempts have also been made to protect the metal particles from atmospheric oxidation by treating the metal particles with polymeric organic binders to form a so-called masterbatch. Such a method can prevent the loss of the above-mentioned metal materials, but a large amount of polymer should be used in order to obtain satisfactory stability of the surrounding environment. The higher the polymer content in the master batch, the greater the problem for use in the manufacture of magnetic recording media in which the pigment is significantly filled. Moreover, the polymers used to stabilize may lead to incompatibility if the master batch is subsequently treated with a binder of different chemical properties. Therefore, the pigments protected by this method are limited in use.

Various known protection methods mentioned above include treating the metal powder with a polymer forming compound to form a polymer layer on the metal particles.

It is also known to use silane coupling agents in magnetic pigments. For example, U.S. Patent No. 4,076,890 describes use to enhance the strength of a magnetic layer, and Japanese Patent No. 51-014,594 describes use to enhance the stability and dispersibility of magnetic metal pigments in a binder. Described.

However, pigments treated with silane coupling agents cannot be well incorporated into all binder systems.

It is therefore an object of the present invention to provide non-ignitable magnetic metals and alloy pigments which do not have the disadvantages mentioned above.

Applicants surprisingly present about 0.2 to 30 weight percent, preferably about 1 to 20 weight percent, and most preferably at least one magnetic metal and alloy pigment in at least one ortho silicate ester and / or hydrolyzate and / or condensate thereof. When coated at about 2 to 15% by weight, it has been found that magnetic metals and alloy pigments are protected from atmospheric oxygen and moisture.

The Applicant has also found that the resistance of the pigment is even more increased when the protective surface layer contains a corrosion inhibitor. Metal particles protected by this method disperse extremely easily and do not cause a problem with compatibility with commercially available binders.

Pyrophoric magnetic metal and alloy powders which can be protected from atmospheric oxygen and moisture according to the invention are described in the literature. These consist mainly of alloys formed from iron, cobalt and nickel or a mixture of these ferromagnetic metals. They may contain from about 0.1 to 10% by weight of one or more heteroatoms such as cadmium, lead, calcium, zinc, magnesium, aluminum, chromium, tungsten, phosphorus or boron. Pyrophoric metals and alloy pigments may also contain small amounts of water, oxides or oxide-hydroxides. They reduce the corresponding metal ions from the corresponding salt solution, electrolytically weld on a mercury cathode, decompose the corresponding metal carbonyls, or add the corresponding metal ions from the solution under the addition of dissolved reducing agents such as borates, hypophosphites, or the like. To a gaseous reducing agent (usually hydrogen) at a temperature of at least 250 ° C. from oxides, oxide-hydroxides, oxalates, formates, or the like, or to be prepared by methods other than the usual methods in the literature. Can be. The particles are homogeneous

The silicic acid esters exhibiting a protective action according to the invention are in particular hydrolyzable, partly by reaction with compounds of the general formula (I), their hydrolysates (including partial hydrolysates), optionally monomeric unglyzed silicic esters Condensates obtained from hydrolysates.

(RO) _n Si (OR ') _4-n

In the above formula,

R may be an alkyl, cycloalkyl or alkenyl group having 1 to 20 carbon atoms, which may be inserted one or more times into the oxygen bridge and / or may be branched, or may be an aryl or aralkyl group,

R 'is an alkyl group having 1 to 4 carbon atoms, n is 0 to 4, preferably 1 to 3.

The alkyl or alkenyl group in the R group in the above general formula may be linear, but at least one branched hydrocarbon group is preferred. For example, the following groups are included.

Isopropyl, tert-butyl, 3-methylbutyl, 2-ethylhexyl, octadecyl and oleyl. Examples of cycloalkyl groups are cyclopentyl, cyclohexyl or cycloheptyl. The aryl group may be a phenyl group, but is preferably a phenyl group (aralkyl group) substituted with alkyl, in particular one or more alkyl groups in the ortho position relative to the ester bond. this

The alkyl group R 'may be branched, but shaped straight chain hydrocarbon groups such as methyl or ethyl are preferred.

Silicate esters of the type shown above can be prepared by methods known in the art. [Reference: W. Noll, Chemie und Technologie der Silkone, 2nd Edition, Publishers Verlag Chemic, Weinheim 1968, page554 et seq.] For the purposes of the present invention, esters are completely free of acidic impurities (especially hydrogen halides). It is preferable to use a production method which can be obtained because such impurities can cause corrosion of the metal, as is known.

According to the invention, the surface of the metal particles can be coated with only one ester, its hydrolyzate and / or its condensate, but the surface layer can also be coated with two or more silicic acid esters, their hydrolyzates or co-singers. It may also be formed from degradation products and / or condensates or co-condensates. The silicate esters used according to the invention therefore do not necessarily have to be homogeneous compounds. In contrast, since any reaction mixture obtained from the above formulation can be used directly to stabilize, a difficult and expensive purification process can be omitted.

Instead of monomeric ort silicate esters, these reaction products can be used from the beginning with insufficient amounts of water together with water to coat the metal particles.

Incomplete hydrolysis leads to the production of polysilicate esters of formulas (A) and (B)

Wherein R is an alkyl, cycloalkyl or alkenyl radical having 1 to 20 carbon atoms, or may be an aryl or aralkyl radical, or a hydrogen atom, which may be inserted once or repeatedly into the oxygen bridge and / or may be branched R 'represents an alkyl group having 1 to 4 carbon atoms, or may be the same as R, O and P are 0 to 50, preferably 1 to 35.

The minimum amount of silicic acid ester required to remove the flammability of metal particles depends on the size of the particles, their specific surface area (BET, nitrogen absorption method) and the porosity of the pigment. The degree of reduction of the pigment is also important. Materials containing small amounts of oxides or oxide-hydroxides can be stabilized even with smaller amounts compared to particle size, BET surface and porosity than safely reduced metal powders. The minimum amount can easily be determined by a simple test by one skilled in the art. In most cases, however, this is necessary not only to remove the flammability of the metal particles, but also to protect the magnetic properties of the particles when stored in air for a long time, especially since the protective surface layer does not adversely affect subsequent processes.

Therefore, the magnetic metals and alloy pigments according to the present invention contain from about 0.2 to 30% by weight of at least one or more of the above-mentioned types of ortho silicate esters, hydrolysates thereof and / or condensates thereof on the surface thereof. 1 to 20% by weight, particularly preferably about 2 to 15% by weight. The magnetic metal and alloy pigments of the present invention have significant resistance to the electrochemical corrosion process even if the pigment is finally contained in commercially available binders of the magnetic recording medium, but greater resistance may be required for use for specific purposes.

Applicants have found that this difficulty can be compensated by the inclusion of one or more corrosion inhibitors in addition to the silicic acid ester coating. Metal powders treated in this way show greater safety against atmospheric oxygen with varying relative humidity.

The corrosion inhibitors used may use known compounds, for example higher amines, aldehydes, alcohols or ketones, amidines, guanidines, nitrogen and / or oxygen and / or sulfur (heteroatoms) -containing heterocyclic compounds [ Examples: urotropin, pyrazole, imidazole, imidazoline, oxazole, isoxazole, thiazole, isothiazole, triazole, triazine, pyridine and the corresponding benzene-condensation systems (e.g. benzimidazole, Benzthiazole, benzotriazole, quinoline or isoquinoline, quinazoline, etc.), sulfur-nitrogen compounds, organic acetylene derivatives, organonitro compounds, phosphonic acids and phosphonocarboxylic acids and their derivatives and salts, nitrogen-containing phosphates Phonic acid or phosphonocarboxylic acid and derivatives and salts thereof, organic and inorganic salts of carboxylic acids such as acetates, benzoates, cinnamates, salicylates and other organic and inorganic phosphates (polyphosphates Bit), and the like phosphate and sulfonate. Of course, suitable mixtures of these compounds can also be used.

The corrosion inhibitor in the silicic acid ester layer is a compound selected from benzotriazole, benzothiazole, benzimidazole, guanidine, amidine and / or metal salts of carboxylic acids, about 0.01 to 5% by weight based on metal weight, preferably about Most preferred are magnetic metals and alloy pigments containing from 0.1 to 4% by weight, particularly preferably from about 0.5 to 3% by weight.

The stabilizing protective layer is treated with a pyrophoric magnetic metal and an alloy pigment by treating the pyrophoric magnetic metal and alloy pigment with a silicate ester which has been finely pulverized by evaporation or spraying in a suitable apparatus (fluid bed reactor, rotary tube, etc.). Can be formed on.

This process can be facilitated by the action of steam and / or catalytically active substances and can also be carried out at temperatures above room temperature if necessary.

However, stabilization may be achieved by treating an untreated pigment in suspension form in an organic and / or aqueous medium with at least one ortho silicate ester and / or polysilicate ester with optional ingredients and at least one corrosion inhibitor, organic and / or It is preferred to carry out in the liquid phase by removing the aqueous phase and drying at about 50 to 250 ° C.

Suitable organic media include lower alcohols such as methanol, ethanol or isopropanol, lower ketones such as acetone or butanone- (2) and lower ethers such as tetrahydrofuran or 1,4-dioxane. . Since magnetic metals and alloy pigments are self-igniting and converted into thermally unstable upon treatment before they are stabilized, this treatment should be carried out in a stable organic / aqueous medium or water.

If necessary, an adjuvant may be added which promotes dispersion of the pigment (dispersant) and / or promotes hydrolysis or condensation of the ester. An example of such a supplement is condensation

Pyrophoric magnetic metals and alloy pigments are suspended in organic and / or aqueous media in conventional manner. Silicic esters and optional preservatives may be added to the liquid phase at any time before or after the preparation of the suspension; When added after preparation of the suspension, it is preferred to add it immediately after the pigment is suspended. The pigment content of the suspension is generally in the range of 5 to 50% by weight.

In most cases, it is desirable to leave the pigment in the suspension for some time before the pigment is separated and dried at 50 to 250 ° C., preferably at about 80 to 150 ° C. During this time (preferably between about 1/2 hour and 5 hours), the suspension is stirred at room temperature or higher, in particular about 20 to 90 ° C.

In particular, the separation of the treated magnetic metal and alloy pigments from the organic and / or aqueous medium and the drying of the pigment by spray drying the suspension are particularly preferably carried out together. The temperature of the drying gas used for this process is about 500 degrees C or less. Spray-dried, coated pigments may be further heat treated at the above-mentioned temperatures and optionally also transferred from an inert gas atmosphere to an oxygen-containing atmosphere.

The process according to the invention is usually carried out in an inert gas atmosphere (including inert gas atmospheres), generally in a nitrogen atmosphere, under complete oxygen exclusion, in order to prevent the oxidation of magnetic metals and alloy pigments. The coated pigment is dried and tempering complete

Despite the use of quantum media, it is surprising that the method described above has been successfully performed without adversely affecting magnetic metals and alloy pigments. Saturation magnetization is reduced to less than or equal to the same percentage by weight of the non-magnetic protective film in the pigment according to the invention. The tremendous decrease in residual magnetization observed in some powder samples is due to the influence of texture and packing, not the residual magnetism of the tape.

Inactivated magnetic metals and alloy pigments according to the invention can be used in the form of dispersions in binders and solvents in conventional manner to produce suitable magnetic recording media. Their dispersion properties, which are dispersed in both organic and aqueous systems, are excellent. There were no incompatibilities. On the contrary, it was not expected that the amount of binder used in preparing the dispersion could be reduced, without any drawbacks, in a proportion corresponding to the weight ratio of the pigmented stabilizing protective layer. This is an advantage especially when high pigment filling is required.

Common binders known in the manufacture of magnetic recording media are in principle also suitable for use in admixture with the magnetic metals and alloy pigments according to the invention. Examples of this binder include copolymers of vinyl chloride and vinyl acetate (carboxyl, hydroxyl or epoxide groups).

Additives of the type commonly used in the manufacture of magnetic recording media can be added at appropriate stages in the preparation of pigment dispersions. Examples of such additives are dispersants, lubricants, plasticizers, fungicides, aging stabilizers, antistatic agents and non-magnetic fillers or pigments.

Magnetic metals and alloy pigments according to the present invention are all forms of magnetic recording media, such as audio tapes, video tapes, instrument tapes, computer tapes, flexible and rigid magnetic cards, flexible magnetic disks, rigid magnetic plates and drum storage media. It can be used to prepare. Magnetic recording media of this type include recording of images and sound, storage of measurement data,

Magnetic data given in the following examples were measured in a 3.5 KOe field. These examples illustrate the invention in detail, but are not intended to limit the scope of the invention.

Example 1

: 1102Gg^-1cm³, 4π Is/, 1855Gg^-1cm³, Br/4π Is : 0.59) 20g을 혼합용 사이렌 사용하에 증류수 200g에 분산시키고 테트라에틸실리케이트 4g을 가한다. 현탁액을 여과하고 여과케익을 105℃에서 질소 스트림하에 10시간동안 건조시킨다. 냉각후, 샘플을 대기에 노출시켜 분쇄한다. 상기 샘플의 자기 분말데이타는 (A)바로 측정하고, 또한 (B) 25℃와 65% 상대 습도하에 박층(thin layer)내, 공기중에서 10일동안 보관후 측정한다. 그 결과는 다음과 같다.A fine pyrophoric metal pigment composed mainly of iron (I ^H c: 772Oe, Br /

: 1102Gg ^-1 cm ³ , 4π Is / 20 g of 1855 Gg ⁻¹ cm ³ , Br / 4π Is: 0.59) was dispersed in 200 g of distilled water using a mixed siren, and 4 g of tetraethylsilicate was added thereto. The suspension is filtered and the filter cake is dried at 105 ° C. under a stream of nitrogen for 10 hours. After cooling, the sample is ground to exposure to the atmosphere. The magnetic powder data of the sample is measured immediately (A) and (B) after storage for 10 days in air, in a thin layer at 25 ° C. and 65% relative humidity. the results are as follow.

Example 2

: 1233Gg^-1cm³, 4π Is/

: 1950Gg^-1cm³, Br/4πIs : 0.63)를 용해기를 사용하여 분산시킨다. 생성한 현탁액을 65℃에서 75분 동안 교반시킨 다음 용매와 에스테르 가수분해 생성물 및 축합생성물을 30밀리바아의 최종압력과 80℃이하의 회전 증발기로 증발시키고, 과립상물질을 불활성 기체하에 90℃에서 한시간동안 열처리한다.Reaction product ^H obtained after reacting 1 mol of tetraethylsilicate and 1 mol of n-octadecanol and removing the low boiling point (final pressure of 20 millibars, sump temperature of 95 DEG C or lower).

: 1233Gg ^-1 cm ³ , 4π Is /

: 1950Gg ^-1 cm ³ , Br / 4πIs: 0.63) are dispersed using a dissolver. The resulting suspension was stirred at 65 ° C. for 75 minutes and then the solvent, ester hydrolysis product and condensation product were evaporated on a rotary evaporator below 30 ° C. and a rotary evaporator below 80 ° C., and the granular material at 90 ° C. under inert gas. Heat treatment for one hour.

Upon cooling the product sample is ground in air. The magnetic powder data measured immediately after using the sample (A) and (B) for 10 days in air in thin layers at 25 ° C. and 65% relative humidity are as follows.

Example 3

3a)

Dissolve 10.4 g of 2-ethylhexyloxy-triethoxysilane in a mixture of 315 g of ethanol and 135 g of distilled water, adjust the pH to 4.5 by adding acetic acid and then stir the solution at room temperature for one hour:

: 973Gg^-1cm³, 4π Is/

^{-1 3} 50 g of pyrophoric iron pigment (I ^H c: 714Oe Br /

: 973Gg ^-1 cm ³ , 4π Is /

^{-1 3}

3b)

8.6 g of 2-ethylhexyloxy-triethoxysilane is dissolved in a mixture of 160 g of ethanol and 65 g of distilled water, adjusted to pH 4.5 with acetic acid, and the solution is stirred at room temperature for 1 hour. Meanwhile, 50 g of a pyrophoric iron pigment as in Example 3a was suspended in a mixture of 155 g of ethanol and 70 g of distilled water in which 1 g of 1.2-pentamethylenebenzimidazole had already been dissolved to prepare a suspension. This suspension is diluted with silane solution using a high speed stirrer. The subsequent procedure is carried out in the same manner as in Example 3a. Magnetic powder data was measured as described in Example 3a, and the results obtained are as follows.

3c)

8.6 g 2-ethylhexyloxy-triethyloxysilane and 1 g Preventol CI6 (trade name: ethoxylated 2-mercaptobenzimidazole, Bayer Actiene Gegelshaft) were added to a mixture of 315 g of ethanol and 135 g of distilled water. After dissolving and stirring the solution for 1 hour at room temperature, 50 g of the same pyrophoric iron pigment as in Example 3a was suspended. The subsequent process is carried out in the same manner as in Example 3a. The magnetic powder data measurement results of the stabilized pigment are as follows.

3d)

8.6 g of 2-ethylhexyloxy-triethoxysilane and 1 g of 1-hydroxy benzotriazole were dissolved in a mixture of 315 g of ethanol and 135 g of distilled water, and 50 g of a pyrophoric iron pigment as in Example 3a was used in the solution. Suspend. The subsequent process is carried out in the same manner as in Example 3a, except that the suspension is spray-dried immediately after preparation. The magnetic powder data of the stabilized pigment are as follows:

3e)

The procedure is carried out in the same manner as in Example 3c, except that 1 g of cyclohexylimino-carboxylic acid dimorphoride is used instead of 1 g of Preventol C16 (trade name). The magnetic powder data of the stabilized pigment were measured as follows:

3f)

The procedure was carried out in the same manner as in Example 3b, except that 1 g of isophoronediamine-bis-caprolactam amidine was used instead of 1 g of 1,2-pentamethylenebenz imidazole. The magnetic powder data measurement results of the stabilized pigment are as follows. :

In order to measure the corrosion resistance of the tape, a short tape sample is prepared by the following method using a non-treated pyrophoric iron pigment as a control and a stabilizing pigment. :

175 revolutions in 2.5 cc of a 12 weight% solution of a polyvinyl chloride / polyvinylacetate copolymer in ethyl acetate and butyl acetate in the same portion, containing 1 g of metal pigment additionally 4% by weight (based on pigment) Dispersion is carried out using a Muller disperser under a 6 kp load, and the lacquer samples obtained are applied onto a 30 μ thick polyester foil using a 90 μ film stretching apparatus and then oriented in a magnetic field and dried. More accurate

Example 4

1182Gg^-1cm³, 4π Is/

: 1917Gg^-1cm³, Br/4π Is : 0.62)를 50g의 1,4-디옥산과 30g의 증류수의 혼합물중 1.9g의 도데실옥시 트리에톡시실란 에멀젼에 코토프(kotthoff)교반기를 사용하여 현탁시키고, 이 현탁액을 40℃에서 3시간동안 교반한 다음 여과하고 여과케익을 질소 스트림중, 150℃에서 8시간동안 건조시킨다. 냉각시킨 생성물 샘플을 공기와 접촉시켜 분쇄한다. 이 샘플의 자성 분말데이타는 (A)바로, 또한(B) 25℃와 65% 상대습도 하에 박층내, 공기중에서 10일동안 보관후 측정한다. 그 결과는 다음과 같다.10 g acicular pyrophoric metal pigment composed mainly of iron (I ^H c: 844Oe, Br /

1182Gg ^-1 cm ³ , 4π Is /

: 1917Gg ^-1 cm ³ , Br / 4π Is: 0.62) using a kotopoff stirrer in 1.9 g of dodecyloxy triethoxysilane emulsion in a mixture of 50 g of 1,4-dioxane and 30 g of distilled water The suspension is stirred for 3 hours at 40 ° C., then filtered and the filter cake is dried for 8 hours at 150 ° C. in a nitrogen stream. The cooled product sample is ground in contact with air. Magnetic powder data of this sample is measured immediately after (A) and (B) storage in air for 10 days in thin layer under 25 ° C and 65% relative humidity. the results are as follow.

Example 5

-메틸페녹시-트리에톡시실란을 80g의 이소프로판올과 20g의 증류수의 혼합물에 용해시키고 암모니아수로 pH를 9로 조절한다. 이용액에, 주로 철로 구성된 15g의 침상 발화성 금속안료(I^Hc : 1313Oe, Br/

: 1137Gg^-1cm³, 4π Is/

: 1935Gg^-1cm³, Br/4π Is : 0.59)를 혼합용 사이렌을 사용하여 분산시킨다. 이어서 안료 현탁액을 85℃에서 한시간 동안 교반하고, 여과한 다음 여과 케익을 질소 스트림중, 130℃에서 9시간동안 건조시킨다. 냉각후 샘플을 공기중에서 분쇄한다. 상기 샘플의 자성분말 데이타는 (A) 바로, 또한 (B) 25℃와 65% 상대습도하에 박층내, 공기중에서 10일 동안 보관후 측정하며, 그 결과는 다음과 같다.4.4g

Methylphenoxy-triethoxysilane is dissolved in a mixture of 80 g of isopropanol and 20 g of distilled water and the pH is adjusted to 9 with ammonia water. 15 g of acicular pyrophoric metal pigment composed mainly of iron (I ^H c: 1313Oe, Br /

: 1137Gg ^-1 cm ³ , 4π Is /

: 1935Gg ⁻¹ cm ³ , Br / 4π Is: 0.59) is dispersed using a mixing siren. The pigment suspension is then stirred at 85 ° C. for one hour, filtered and the filter cake is dried for 9 hours at 130 ° C. in a nitrogen stream. After cooling the sample is ground in air. The magnetic powder data of the sample was measured after (10) storage for 10 days in air, in a thin layer at 25 ° C. and 65% relative humidity, immediately after (A), and the results are as follows.

Example 6

: 1182Gg^-1cm³, 4π Is/

: 1910Gg^-1cm³, Br/4π Is : 0.62)를 용해기를 사용하여 분산시키고 생성된 현탁액을 45℃에서 2시간동안 교반시킨 다음 질소로 작동시키는 실험실용 분무-건조기(모델 HO IRA mini 분무-건조장치 ; 건조용 기체온도 : 180내지 200℃)에 주입한다. 분무-건조된 안료를 질소 대기하에 110℃에서 2시간동안 조질화 시킨다. 다음의 자성 데이타는 상기 샘플을 (A)바로, 또한 (B)25℃와 65% 상대습도하에 박층내, 공기중에서 10일동안 보관후 측정한 것이다. :28.7 wt% tetraethyl silicate, 43.3 wt% 2-ethylbutyloxy-triethoxysilane, 22.9 wt% bis- (2-ethylbutyloxy) -diethoxysilane, 6.8 wt% tris- (2- 285 g of a mixture of ethylbutyloxy) -ethoxysilane, 0.9% by weight ethanol and 0.4% by weight 2-ethylbutanol was dissolved in a mixture of 6750g ethanol and 2250g distilled water and acetic acid was added to adjust the pH of the solution to 4.2. do. 90 minutes stirring this solution at room temperature ^H

: 1182Gg ^-1 cm ³ , 4π Is /

: 1910Gg ^-1 cm ³ , Br / 4π Is: 0.62) was dispersed using a dissolver and the resulting suspension was stirred at 45 ° C. for 2 hours and then operated with nitrogen, a laboratory spray-dryer (model HO IRA mini spray- Drying device: Drying gas temperature: 180 to 200 ℃). Spray-dried pigments are crude for 2 hours at 110 ° C. under a nitrogen atmosphere. The following magnetic data is measured after (10) storage of the sample immediately in (A) and (B) in a thin layer under air at 25 ° C. and 65% relative humidity for 10 days. :

Manufacture of magnetic tape

a) physical dry binder system:

236 g of stabilized metal pigment was dispersed in a solution of 53 g of polyvinylchloride / polyvinyl acetate copolymer, 4.5 g of silicone oil and 6 g of a dispersant in a solution of 440 g of a mixture of ethyl acetate and butyl acetate in the same portion, followed by a pebblemil; Medium: glass beads 1, 2 and 3 mm in diameter) for 3 hours 30 minutes. The mixture is then filtered and the lacquer applied to a 12μ thick polyester foil to orient the iron pigment dispersed in the lacquer in the magnetic field and then dry the magnetic layer. The thickness of the layer upon drying was about 6μ.

Magnetic measurement results of the tape:

I ^H c: 1020Oe (1002Oe)

Br: 3050G (3150G)

Br / Bs: 0.78 (0.78)

The values in parentheses are the data of the corresponding tapes obtained from the unstabilized pigments. Both tapes have a similar volume packing factor for the magnetically active material.

b) cross-linking binder system

275 grams of stabilized metal pigment was added to 14.4 grams of polyvinylchloride / polyvinylacetate copolymer, 5 grams of acrylonitrile / butadiene copolymer, 19.4 grams of polyester urethane, 92.4 grams of hydroxyl-containing polyacrylate and 8.5 grams of dispersant. Was dispersed in a solution dissolved in a mixture of 231 g of tetrahydrofuran, 115.5 g of methyl isobutyl ketone, and 51.7 g of cyclohexanone, and the mixture was mixed with a pebble mill (grinding medium: glass beads having a diameter of 1,2 and 3 mm). Grind for 3 hours 30 minutes. 19.4 g of polyfunctional aliphatic isocyanate is added 30 minutes before the end of the milling time to crosslink the binder system. The product is then filtered and the lacquer is applied to a 12 μm thick polyester foil to orient the iron pigment dispersed in the lacquer in the magnetic field and then dry the magnetic lacquer. Its thickness was about 6 mu in the dry state.

Magnetic measurement results of the tape:

I ^H c: 1039Oe Br / Bs: 0.76

Br: 27600G

c) aqueous physical dry binder system:

240 g of stabilized metal pigments are suspended in 176 g of distilled water containing 8% by weight (based on pigment) of dispersant and in this suspension a mixture of 200 g of 50% acrylate / styrene copolymer dispersion and 10 g of butyl diglycol acetate. After addition, the whole mixture is ground for 3 hours and 30 minutes with a pebble mill (grinding medium: glassmead having a diameter of 1,2 and 3 mm). The product is then filtered and the lacquer is applied to a 12 μm thick polyester foil to orient the iron pigment dispersed in the lacquer in the magnetic field. Dry the magnetic layer. The thickness of the layer upon drying was about 6μ.

Magnetic measurement results of the tape:

I ^H c: 1050Oe Br / Bs: 0.72

Br: 2600G

Example 7

: 1108Gg^-1cm³, 4π Is/

: 1847Gg^-1cm³, Br/4π Is : 0.60)를 분산시키고, 이 에멀션을 50℃에서 45분동안 교반시킨 다음 불활성 조건하에 약 200℃의 건조용 기체온도에서 분무 건조(모델 HO IRA Mini5.8 g of the reaction product obtained after reacting 1 mole of tetraethyl silicate with 1 mole of 9-9 octadecen-1-ol and removing volatile components (final pressure: 18 mbvar, sum temperature: 175 ° C. or lower) Emulsify in a mixture of 270 g isopropanol and 180 g distilled water and adjust the pH to 6.8 with ammonia. In this emulsion, 50 g of acicular pyrophoric metal pigment composed mainly of iron (I ^H c: 852Oe Br /

: 1108Gg ^-1 cm ³ , 4π Is /

: 1847Gg ^-1 cm ³ , Br / 4π Is: 0.60) and the emulsion was stirred at 50 ° C. for 45 minutes and then spray dried at a drying gas temperature of about 200 ° C. under inert conditions (Model HO IRA Mini).

Example 8

: 1005Gg^-1cm³, 4π Is/

: 1771Gg^-1cm³, Br/4π Is : 0.57)를 상기 에멀션에 분산시킨다. 생성된 현탄액을 실온에서 30분동안 교반시킨 다음 실험실용 분무건조기(모델 HO IRA Mini 분무건조장치 사용 ; 건조용 질소기체온도 : 200내지 220℃에 공급한다. 분무-건조된 안료 샘플을 공기중에 노출시킨다. 다음의 자성 분말데이타는 상기 샘플을(A) 바로, 또한(B) 25℃, 65%상태 습도하에 박층내, 공기중에서 10일동안 보관후 측정한 것이다.13 g of 2-ethoxy ethyloxy-triethoxysilane were emulsified in a mixture of 135 g of ethanol and 315 g of distilled water, and 50 g of needle-ignition iron pigment (I ^H c: 999Oe Br /

: 1005Gg ^-1 cm ³ , 4π Is /

: 1771Gg ⁻¹ cm ³ , Br / 4π Is: 0.57) is dispersed in the emulsion. The resulting suspension was stirred at room temperature for 30 minutes and then supplied to a laboratory spray dryer (using a model HO IRA Mini spray dryer; nitrogen gas temperature for drying: 200 to 220 ° C. Spray-dried pigment samples were placed in air. The following magnetic powder data were measured after (A) storage of the sample immediately in (A) and (B) for 10 days in a thin layer, air at 25 ° C., 65% state humidity.

Example 9

: 1150Gg^-1cm³, 4π Is/

: 1916Gg^-1cm³, Br/4π Is : 0.60)를 용해기를 사용하여 264g의 이소프로판올 및 396g의 증류수중 12.8g 사이클로헥실옥시-트리메톡시실란 에멀젼에 현탁시킨다. 이 에멀젼을 암모니아수를 가하여 먼저 pH5로 조절한다. 금속안료 현탁액을 75℃에서 30분동안 교반시킨 다음 질소 대기하에 분무-건조(모델 HO IRA Mini 분무-건조장치 사용 ; 건조온도 : 약 200℃)시킨다. 냉각된 생성물 샘플을 공기중에 노출시킨다. 다음의 자성분말 데이타는 상기 샘플을 (A)바로, 또한 (B)25℃와 65% 상대습도하에 박층내, 공기중에서 10일 동안 보관후 측정한 것이다.75g pyrophoric metallic pigment composed mainly of iron (I ^H c: 845Oe Br /

: 1150Gg ^-1 cm ³ , 4π Is /

: 1916 Gg ⁻¹ cm ³ , Br / 4π Is: 0.60) is suspended in a 12.8 g cyclohexyloxy-trimethoxysilane emulsion in 264 g of isopropanol and 396 g of distilled water using a dissolver. The emulsion is first adjusted to pH5 by adding ammonia water. The metal pigment suspension is stirred at 75 ° C. for 30 minutes and then spray-dried (using a model HO IRA Mini spray-dryer; drying temperature: about 200 ° C.) under a nitrogen atmosphere. The cooled product sample is exposed to air. The following magnetic powder data is measured after (10) storage of the sample immediately in (A) and (B) at 25 ° C. and 65% relative humidity for 10 days in air.

Example 10

: 973Gg^-1cm³, 4π Is/

: 1864Gg^-1cm³, Br/4π Is : 0.52)를 상기 에멀젼에 현탁시킨다. 이 현탁액을 실330 g of 2-ethylbutyloxy-triethoxy silanol, reacted with 18 g of distilled water at 70 ° C. in the presence of immobilized acid with a catalyst and dissolved in 60 g of ethanol. The cooled reaction mixture is filtered and low boiling point components are removed at a final pressure of 30 millibars and a temperature below 70 ° C. 5 g of the obtained product was emulsified in a mixture of 88 g of methanol and 352 g of distilled water, and 50 g of acicular pyrophoric metal pigment mainly composed of iron (I ^H c: 714 Oe Br /

: 973Gg ^-1 cm ³ , 4π Is /

: 1864Gg ⁻¹ cm ³ , Br / 4π Is: 0.52) are suspended in the emulsion. Seal this suspension

Example 11

: 1086Gg^-1cm³, 4π Is/

: 1742Gg^-1cm³, Br/4π Is : 0.62)를 분산시킨다. 이 현탁액을 30밀리바아의 최종압력과 150℃이하 온도에서 회전 증발기로 증발시키고 과립상 물질을 질소대기하에 냉각시킨다. 냉각시킨 생성물 샘플을 마쇄하고 공기중에 노출시킨다. 다음의 자성분말 데이타는 상기 샘플을 (A)바로, 또한 (B) 25℃와 65% 상대습도2.0 wt% tetra ethyl silicate, 53.4 wt% 2-ethylhexyloxy-triethoxysilane, 40.3 wt% bis- (2-ethylhexyloxy) -diethoxysilane, 3.7 wt% Tris- ( 397 g of a mixture consisting of 2-ethylhexyloxy) -ethoxysilane and 0.6 wt% ethanol is reacted with 17 g distilled water at 70 ° C. in the presence of an immobilized acid as a catalyst and dissolved in 80 g ethanol. The reaction product is cooled and then filtered and the low boiling point component is removed at a final pressure of 30 millibars and a temperature below 70 ° C. In an emulsion of 6 g of the obtained product dissolved in 440 g of distilled water, 50 g of pyrophoric metal pigment composed mainly of iron (I ^H c: 1094Oe Br /

: 1086Gg ^-1 cm ³ , 4π Is /

: 1742Gg ^-1 cm ³ , Br / 4π Is: 0.62) are dispersed. The suspension is evaporated on a rotary evaporator at a final pressure of 30 millibars and a temperature below 150 ° C. and the granular material is cooled under nitrogen atmosphere. The cooled product sample is ground and exposed to air. The following magnetic powder data indicates that the sample is (A) and (B) 25 ° C. and 65% relative humidity.

The above specification and examples are not intended to limit the scope of the invention, and any changes may be made without departing from the spirit and scope of the invention.

Claims (1)

Magnetic metal pigments and their alloy pigments, characterized by coating the metal with a coating comprising at least about 0.2 to 30% by weight of ortho-silicate esters thereof, hydrolysates thereof and condensation products thereof, of magnetic metals and alloys thereof. Manufacturing method.