DE2727863A1 - PIGMENTARY, BRILLIANT KEYFLOWERS YELLOW MONOCLINES WISMUTH VANADAT AND THE PROCESS FOR ITS PRODUCTION - Google Patents

Description

Pigmented, bright cupflower yellow monoclinic Bismuth vanadate and process for its preparation

The present invention relates to pigmented luminous cowslip yellow monoclinic bismuth vanadate and processes for its manufacture.

A pigment is an insoluble, finely divided solid that is is incorporated into paints, plastics and inks to impart color and / or opacity. Ideally, a pigment should have tinting strength, i.e. that when mixed with one * Only a small amount of color pigment used in the manufacture of the ink necessary is; further it should be intensity, i.e. purity of hue or lack of dullness or grayness; Lightfastness, i.e. resistance to color change when a pigmented item is exposed ♦ to sunlight and resistance against bleeding, i.e. little color migration in a pigmented object. Further, it is desirable for many purposes that a pigment have good hiding power, i.e., ability effective opacity of a pigmented object, has "

709881 / J) £ 8 1.

the main intense yellow pigments currently in use are lead chromate, cadmium sulfide, nickel titanate and numerous organic materials, such as certain azo compounds lead *, chromate and cadmium sulfide have good covering power; however, the current trend is from the use of these compounds gone as pigments due to their potential toxicity. Nickel titanate has good opacity, but not the color strength and high Intensity that is desired in a high quality pigment The organic pigments usually show a high color strength, however, poor coverage and often poor resistance to bleeding.

Therefore, there is a need for a non-toxic, strong opaque yellow pigment that continues to have good color strength, high Has intensity and good lightfastness and does not bleed in organic solvents or vehicles.

Bismuth vanadate appears in nature in one, usually as Pucherite designated, orthorhombic shape. Pucherit is a dull yellow-brown mineral unsuitable as a pigment; it is similar in color to limonite, a dull yellow-brown Iron oxide, which has never been produced as a luminous, high-intensity pigment despite repeated attempts.

Various references have described the synthetic preparation of bismuth vanadate, such as I .M. Gottlieb and CR. Rome, "Preparation and Thermal Properties of Bismuth Orthovanadate", Thermal Analysis, Vol. 2, Proceeding Third ICTA Davos (1971), pp. 303-311; RS Roth and 3.W. Waring "Synthesis and Stability of Bismutotantalite, Stibiotantalite and Chemically Similar ABO ₄ Compounds", The American Mineralogist, Vol. 48,

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(Mov./Dec, 1963), pp. 1348-56; H.E. Sivanson et al "Standard X-flay Diffraction Powder Patterns, "National Bureau of Standards Report, No. 7592 (Aug. 1962); Eduard Zintl and Lugwig V an in ο "Process For The Manufacture of Pure Bismuth Vanadate"; and German * Patent 422 947 (1925). As in the case of yellow However, iron oxide, none of the above methods of making Wiainut vanadate as a bright yellow pigment has been successful.

According to the invention, a pigmentary, monoclinic uismuth vanadate is created that has a cowslip yellow tone and is non-toxic and has a high covering power, good color strength, high intensity and good lightfastness and does not bleed in organic solvents or carriers. This pigmentary bright yellow bismuth vanadate has a pure monoclinic crystal structure as determined by X-ray diffraction, shows an increase in reflectance from 450-525 nm of at least 65 units using type I lighting and a green filter reflectance in color of about 60% (preferably 64 %) %), it has a surface area of about 2-22 m / g and such neesonton lightfastness in color that it lasts for 44 hours

@only . ... — ...- W-- Exposure / loses about 11% or less reflectance.

Furthermore, a process for the production of the bismuth vanadate pigment according to the invention is created, which is characterized in that a solution of Bi (NO ^) ₃ .5H.0 in nitric acid with a solution of alkali metal vanadate, preferably Na, V0., In an aqueous base is created the group of sodium and potassium hydroxide mixes, whereby the mixing conditions are controlled, um a hquimolar batch combination of the solutions under

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causing turbulent conditions to obtain a bismuth vanadate gel suspended in a solution containing dissolved alkali nitrate; the molar ratio of Bi ⁺ to VO ^ in this suspension is between β tu / a 0.95: 1.00 to 1.10: 1.00, and the normalities of the acidic and basic solutions are set before mixing so that the pH of the suspension is between about 1.0-8.0, preferably 1.5-2.0; then, if necessary, the pH of the suspension is adjusted to about 1.9-3.6 with an alkali metal hydroxide from the group consisting of sodium or potassium hydroxide or optionally with an acid such as nitric or sulfuric acid, and the gel is turned off the suspension separated, washed with water until it contains about 20% or less of alkali metal nitrate, based on the theoretical Wismutvanadatausbeute, and then calcined about 0.4-3 hours at about 200-500 ⁰ C..

As mentioned, the present invention relates to pigmentary, monoclinic bismuth vanadate and methods for the same Manufacturing. The pigmentary bismuth vanadate is bright cowslip yellow and has high intensity, good color strength and good color Lightfastness.

According to the determination by X-ray diffraction, the pigmentary bismuth vanadate according to the invention lies completely in the monoclinic crystal phase before. The X-ray diffraction measurements were made with a Debye-Scherrer powder camera using Cu., Radiation from a Norelco unit, Type 12045B, at 40 kV / 20mA and one 6 hour exposure.

The pigmentary bismuth vanadate according to the invention shows a considerable increase in reflectance in the region of the visible spectrum between 450-525 nm, which shows that it is cowslip yellow

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Is color and has high intensity and good color strength. the

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The reflectance used here is a comparison of the reflective / and diffuse reflectance of a known standard with the sample to be tested using Type I lighting. The reflectance is measured on a Cary model 14 spectrophotometer which is provided with an integrating ball, which is painted with Eastman and eiGer reflectance paint no. 6080. The too The sample to be tested is prepared by adding 10% by weight of the Bismuth vanadates with 90 weight percent barium sulfate, the Eastman Reflectance standard No. 6091, until a uniform level is achieved Powder mixes. Then the reflectance of the known standard, namely Eastmen reflectance standard No. 6091, is compared with the compared to the sample. In the range of the visible spectrum from 450-525 nm, one shows the pigmentary bismuth vanadate according to the invention sample containing an increase of at least about units of reflectance on a scale on which the Eastman Reflectance Standard No. 6091 shows a reflectance of 100 units over the entire visible spectrum. Actually show many of the samples show an increase in reflectance of at least about 70 units or more. The higher the change in reflectance within the specified spectral range, the greater the intensity and color strength of the sample.

The intensity and lightfastness of the bismuth vanadate pigment in a color are measured on color strips produced to completely cover them. The paint is made by dispersing the pigment in a binding agent in a weight ratio of 2: 1 pigment to binding agent using a Hoover pickguard. The binder consists of 98.9 parts by weight of clear varnish no.

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from Superior Varnish and Drier Company, Merchanteville, N.3., 1 part (as lead) lead Nuodex dryer (contains 24 % lead) and 0.1 part by weight (as manganese) manganese Nuodex ^ -> dryer (contains 6 % manganese). The strips are placed in a well-ventilated room at 25 ° C for about 72-120 hours. and dried to less than about % moisture.

The intensity is determined by the green filter reflectance of a mass tone tire. It is expressed as the percentage of green filter reflectance measured with a Gardiner multi-corner reflectometer, serial no. 40 (Gardiner Laboratory, Inc., Bethesda, Md.) Using a white reflectance standard at a setting of 86.1 and light from a General Electric CVS projector lamp passed through the green tri-stimulus filter supplied with the Gardiner Ruflektoraeter. The Gardiner multipurpose reflectometer is described in the National Bureau of Standards Research Paper RP 1345, dated Nov. 1940, by RS Hunter and in the National Bureau of Standards Circular C429, dated July 30, 1942, by RS Hunter. The higher the percentage reflectance of the strip, the more intense the color. The intensity of the inventive Wistnutv / anadate is such that it has a green filter reflectance of at least about 60 %, preferably 64 % .

The lightfastness is determined after the dried color strips have been exposed continuously for 44 hours in an Atlas color Fade-O-meter ^ H type FDA-P. A Gardiner multipurpose reflectometer is used to measure green filter reflectance as above used within one hour before and one hour after exposure. The percentage decrease in reflectance after the

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Exposure, based on the initial reflectance, is the percentage fade-ometer ^^ darkening; the lower this percentage, the better the lightfastness of the pigment. The bismuth vanadate according to the invention usually shows a percent fade-o-meter darkening of about 11 % or less, preferably about 7 % or less, after 44 hours of exposure.

The surface area of the bismuth vanada tea is approximately 2-22 m / g. For use in film-forming preparations such as paints and inks, a surface area of about 8-22 m / g is preferred. For use in plastic preparations, a surface area of about 2-4 m / g preferred due to the increased heat resistance. The surface area is measured on a Perkin-Elmer Sorptometer, Shell Model 212C, measured using the manufacturer's recommended method.

The pigmentary bismuth vanodate is prepared by mixing a solution of up to 0.8 M Bi (NOj) ₃ .5H ₂ O in up to about 4, ON nitric acid, preferably about 0.2M Bi (NO ₃ ),. 5H-O in about 1. ON nitric acid, with a solution of alkali vanadate, preferably sodium vanadate, in a concentration up to about 0.32M in up to about 1.6N aqueous base from the group of sodium and potassium hydroxide · The upper concentration limits of the reaction solution are determined by the solubility certainly; However, the control of the equimolar batchwise mixing is easier with more dilute solutions. In a preferred embodiment, a solution of about 0.2M Na ₃ VO. used in about 1.0N aqueous sodium hydroxide · The solutions are preferably ^{mixed at about 20-3O 0} C., but can also be wiped ^{at 10-100 0 C.}

The molar ratio of Bi ³⁺ to VO ^ ³ "can be about 0.95: 1.00 to etu / a 1.10: 1.00, preferably about 0.98: 1.00 to 1.02: 1.00 As mentioned, it has been found that a slight molar excess of Bi ⁺ or VO. ~ can be used.

The normalities of the acidic and basic solutions are before the Mixing adjusted so that the pH of the reaction mixture, is about 1.0-8.0. A pH of about 1.5-2.0 is preferred, because it provides a gel from which a pigmentary monoclinic bismuth vanadate product with optimal intensity and / or can be obtained Can get lightfastness.

The preferred method of mixing the solutions takes place in a flow reactor, which allows a very rapid batch combination Provides conditions of high turbulence. A batch combination means that small, practically etoichiometric amounts in each case to be implemented at a time. That avoids relatively large ones

Gradients and a stoichiometrically unbalanced state,

simultaneous which occurs when / mixing large amounts of reactants. This imbalance leads to undesirable side reactions. The devices used are expediently T-mixers or flow reactors.

If the solutions of Bi (NO ₃ I _{3 .5H 3} O and alkali vanadate are mixed under the above conditions, a suspension of bismuth vanadate gel in an alkali nitrate solution (sodium and / or potassium nitrate) is formed. The bismuth vanadate gel mentioned here refers to a water-containing one According to Röntgen-Analyae amorphous bismuth vanadium oxide precipitate, which contains trapped water.

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After the gel has formed, the pH of the suspension must be on 1.9-3.6 should be adjusted if it is found to be outside this range Potassium hydroxide can be adjusted upwards; on the other hand, if it is above about 3.6, then it must be treated with an acid such as nitric or Sulfuric acid, to be adjusted down.

The pH of the suspension is preferably adjusted to 3.3-3.5, since in this way a gel is obtained which, after calcination, becomes a pigmentary monoclinic bismuth vanadate provides the desired lightfastness and heat resistance. The early setting the pH of the suspension to the final, above-mentioned ranges is advisable, although the Wisnutvanadatgel under certain Circumstances at room temperature until several hours before pH adjustment is stable.

The gel is then removed from the suspension, preferably by filtration; it is collected and if it contains greater than about 20 % alkali nitrate based on the theoretical yield of bismuth vanadate it must be washed with water until the level is about 20 % or less. It is advisable to leave about 5-7 % alkali nitrate in the gel.

Then, the gel at a temperature of 200-500 ⁰ C, for about 0.4-3 hours, preferably about 1 hour at about 380-460 ⁰ C., is calcined. According to X-ray refraction, the bismuth vanadate pigment is completely in the monoclinic phase.

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Another method of making pigmentary monoclinic bismuth vanadate consists of mixing a solution of up to about 0.8M Bi (NO,) _{.5H 2} O, preferably about 0.2M, in aqueous nitric acid up to A, ON, preferably about 1 , ON, with a solution of alkali vanadate (sodium or potassium vanadate), preferably up to about 0.32M Na, VO., In up to about 1.6N aqueous base from the group of sodium or potassium hydroxide, preferably about 0.2M Well, VO. in approximately 1.0 N sodium hydroxide · The solutions are preferably mixed at 20-30 ⁰ C., but can also be mixed to 10-100 ⁰ C..

The molar ratio of Bi to VO ^ can be about 0.90: 1.00 to 1.10: 1.00, preferably about 0.98: 1.00 to 1.00: 1.05, indicating that either an excess of Bi or VO ^ "can be used. The symbol VO." used herein means one Pentavalent vanadium compound in an aqueous solution, but does not mean a specific pentavalent vanadium compound that is present at a given pH and vanadium concentration.

The normalities of the acidic and basic solutions are before the Mix adjusted so that the pH of the reaction mixture is about 1.0-11.0. A pH of about 1.5-4.0 is preferred because it provides a gel from which a pigmentary monoclinic bismuth vanadate product of optimal intensity and / or Lightfastness can be obtained.

The solutions must be mixed in the manner described for the first method to achieve a squimolar batch combination of the solutions under conditions of high turbulence

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and result in a suspension of bismuth vanadate gel in Alkali nitrate solution.

The gel should preferably not be removed from the suspension until the pH of the suspension stabilizes at about 2.2-6.0 became. If the pH of the suspension is below about 2.2, then it can be adjusted upwards with aqueous sodium or potassium hydroxide; is he greater than about 6.0, then it can be adjusted down with an acid such as nitric or sulfuric acid. The quick setting of the Adjusting the pH of the suspension to the final range listed above is advisable, although the bismuth vanadate gel is below certain May be several hours at room temperature prior to pH adjustment is stable.

The gel is then removed from the suspension, preferably by filtration; it is collected and if it contains greater than about 10 % alkali nitrate based on the theoretical yield of bismuth vanadate it must be washed with water until the level is about 10 % or less.

Then, the gel in water, is preferably heated at least 0.2 hours at about 60-200 ⁰ C for about 1-2 hours at about 90-100 ⁰ C., to convert it in pigmentary monoclinic bismuth vanadate. While the aqueous digestion should the pH of the suspension between 2.2 to 6.0, preferably maintained between 3.0-3.5, by as needed ^ma "adding a suitable acid or BAEE. Suitable acids include nitric , Sulfuric, hydrochloric, hydrobromic or phosphoric acid. Suitable bases include aqueous sodium or potassium hydroxide

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Temperatures above about 10O ⁰ C., of course, the heating must take place under pressure. When using excess vanadium, especially a molar ratio of Bi to VO. "Of 0.90-0.95: MUQ be the pigment is washed after the heating step by 15-30 minutes long suspending in water at 50-100 ⁰ C. 1.00, wherein the pH ässrigen with a u / base from the group of sodium and potassium hydroxide is kept at 6.0-9.5.

After completion of digestion the pigment tdird filtered and b for example at ettua 13O ⁰ C. dried. The product is obviously cowslip yellow bismuth vanadate, which according to Rtintgen refraction is completely in the monoclinic phase.

In any of the above methods, pH adjustment can be done. after the gel has been removed from the suspension. To easily adjust the pH of the gel, however, it should be put in water again be suspended. If the pH of the gel has been correctly adjusted, it is stable under certain circumstances for up to about a week at room temperature.

In any of the above processes, the alkali vanadate solutions can be prepared by adding a pentavalent vanadium compound, such as V ₃ O ₅ , Na ₃ VO ₄ , NA ₄ V ₂ O ₇ , NaVO ₃ or K ₃ VO ₄ , in an aqueous base from the group dissolves from sodium and potassium hydroxide.

After making the bismuth vanadate pigment tea according to one of the above method, its lightfastness can be improved by placing it in a dense amorphous coating on silica encapsulated or treated with aluminum pyrophosphate. The silica coatings can be produced by known processes

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(see e.g. reissue US PS 3 437 502 and US PSS 3 639 133, 3 370 971 and 3 885 366).

The following examples illustrate the present invention without restricting it. Unless otherwise stated, all parts, percentages and proportions are mixed parts, Cew .- ^ and Cetuicht conditions.

Example 1_ Nine samples were prepared using the following procedure:

A solution of 7.58 g Na ₃ VO. in 200 ecm 1, ON NaOH was converted into a solution of 20 g of Bi (N0 ₃ ) ₃ within 2 minutes while stirring. 5H.0 in 200 ecm 1.0N ENT, cast. The mixture was stirred vigorously and a yellow-orange precipitate formed immediately. The mixture was then adjusted to pH 3.5 with 2.0 N NaOH. The mixture was stirred for half an hour, filtered, distilled with 400 ecm. "Washed water and filtered again There is a remaining on the filter paper Wismutvanadatgel was collected and 1 hour at ⁰ C. AOO to the formation of pigmentary monoclinic BiVO. calcined.

The average green filter reflectance of these nine samples from Wiemut vanadate was 68.0, and their average percent fade-o-meter darkening after 44 hours of exposure was 11.0.

Eight samples were prepared using the following procedure:

The above procedure was repeated, except that the Na ₃ VO. in NaOH and the Bi (NOj) ₃ , 5H ₃ O dissolved in HNO ₅ and using • in ·· T mixer of 1 mm internal diameter at 2.8 kg / cm within about 2 minutes to achieve a turbulent

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a'quimolar mixing was combined

The average green filter reflectance of these 8 samples of Wiemut vanadate pigment was 69.0, its average percent fade-o-meter darkening after 44 hours of exposure at 6.7.

This example shows that the turbulent equimolar mixing improves the lightfastness of the bismuth vanadate pigment. Example 2

Ee a mixture was prepared by combining the following ingredients in a T-mixer of 1 mm internal diameter at 2.8 kg / cm within about 2 minutes: (i) 78.4 g Bi (NO ₃ ) ₃ .5H _{2 O} in 200 ecm 4, ON ENT ₃ , then with 60 ecm

2, ON ENT, and 545 ecm of water diluted; and (ii) 30.3 g Na ₃ VO _{4 dissolved} in 500 ecm 1.6N NaOH, then with water

diluted to 800 ecm.

Sufficient HNO ₃ was added to component (i) or aqueous NaOH to component (ii) so that the pH of the mixture of the two materials was between about 1.5-2.0. _{The mixture was transferred to a 3} l beaker which contained 120 ecm of water which had been adjusted to pH 2.3 with 0.5N HNO 3. The contents of the beaker were stirred for 1 minute, then the pH was adjusted to 3.2 with 0.5N NaOH. This was then adjusted to 3.4 and maintained for 30 minutes. The contents were filtered, washed with 250 ecm of water and then again with the same amount of water. After filtering, a bismuth vanadate gel collected on the filter paper and was divided into 3 equal samples. Each sample was converted to pigment monoclinic using the procedure in Table I and tested for the properties listed.

- V5 - Table I.

Sample Umuiandlunqsvpfffahren LichtechthH **. * Surface area A with 250 ecm of water is 2.1 13.6

wash, then 4 hours heated to boiling

B at 39O ⁰ C. Calcined 1.5 hours 4.7 6.8 C at 45O ⁰ C. 1.5 std calcined 6.9 2.3

** Percentage of fade-ometer darkening = % change in reflectance after 44 hours of fade-ometer exposure

As can be seen, one made by heating in water monoclinic bismuth vanadate pigment has better lightfastness than the samples produced by calcining. Next has a through By heating the bismuth vanadate pigment made in water a higher surface area, which means that it has a greater color strength per unit weight than the calcined samples.

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A mixture was prepared by combining the following ingredients in a T mixer with an internal diameter of 1 mm at 2.8 kg / cm within about 2 minutes: (i) 80.0 g of Bi (NO ₃ ) ₃ .5H _{2 O} , dissolved in 204 ecm 4, ON ENT ₄ , then with

20 ecm 2, ON HNO ₃ and 581 ecm of water diluted; and (ii) 30.3 g Na ₃ WO _{4 dissolved} in 500 ecm 1.6N NaOH, then with water

diluted to 800 ecm.

Sufficient HNO _{3 was added} to ingredient (i) or aqueous NaOH to ingredient (ii) so that the pH of the mixture of the two materials was about 1.5-2.0. The mixture was transferred to a 3-1 beaker containing 1200ccm of water which had been adjusted to pH 2.3 _{with 0.5N HNO 3.} The contents of the beaker were stirred for 1 minute, then the pH was adjusted to 3.2 with 0.5N NaOH. It was then set to 3.4 and 30

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Maintained minutes. After filtering, a bismuth vanadate gel collected on the filter paper and was divided into 4 equal samples. Samples A and B were not washed. Sample C was washed twice on the filter with 250 ecm of water each time. Sample D was suspended twice with 500 ecm of water each time and filtered again each time. Each sample was converted by calcining for 1 hour at 450 ⁰ C. monoclinic bismuth vanadate. (The exact amounts of water and the procedure used to wash the bismuth vanadate gel should be adjusted so that the amounts of NaNO, shown in Table II, remain in the samples.)

Table II

Sample amount of NaNO-. in the sample, or surface area, based on the dry weight of the pigment m / g ; %

1.4 1.4 3.5 4.9

The results of Table II show the effect of residual Sodium nitrate in the gel before calcination. As mentioned above, It has been found that the surface area of the pigmentary bismuth vanadate made from the gel decreases as the amount of sodium nitrate in the gel increases, with a corresponding decrease in color strength per unit. The preferred particle size for thermal stability is 2.4

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free game 4

A. 44 B. 44 C. 10-20 D. AZ ₃

Ee was made a mixture by combining the following ingredients in a T-Mlecher of 1 mm internal diameter at 2.8 kg / cm produced within about 2 minutes:

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(i) 80.0 g Bi (N0 ₃ ) ₃ .5H ₂ 0, dissolved in 204 ecm 4, ON HNO ₃ , then with

20 ecm 2, ON HNO ₃ and 581 ecm water, and (il) 30.3 g Na ₃ VO ₄ , dissolved in 500 ecm 1.6N NaOH, then with

Water diluted to 800 ecm.

_{Sufficient HNO 3 was} added to component (i) or aqueous NaOH to component (Ii) so that the pH of the mixture of the two materials was about 1.5-2.0. The mixture was in inen • 3-1 cup transferred, the 1200 cc water contained that "it 0.5N HNO uiar adjusted to pH 2.3. ₃ The contents of the beaker were stirred for 1 minute , then the pH was adjusted to 3.2 with 0.5N NaOH. The pH was then adjusted to 3.4 and maintained for 30 minutes. The content, a suspension of bismuth vanadate gel, was filtered and washed on the filter twice with 500 ecm of water each time. After filtration, the collected on the filter paper Wismutvanadatgel was performed by 1 hour at 450 ⁰ C. Celcinieren in monoclinic bismuth vanadate. This material is referred to as Sample A.

Sample B was prepared according to the procedure used for Sample A, wherein the gel, however, resuspended after filtration of the suspension in 500 cc of water was filtered and again suspended in 500 cc of water and filtered again.

Sample C was prepared by resuspending 10g of Sample A in 500 cc of water, filtration, resuspending in 500 cc of water, filtering and drying at 14O ⁰ C..

Table III shows the relative heat resistance of the pig- ■ gent in plastic with different sodium nitrate content.

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Table III

Sample NaNO. Amount in sample, relative heat resistance * of the weight of the pigment in relation to the dry pigment in plastic; %

A 6.4 extremely stable

B 0.9 less stable than A, however

more stable than C

C 0 less stable than A or B

D 44 ** the least stable

* The heat resistance tests were carried out separately in polystyrene and in ABS using a Brabender Plastograph, Type PL 4000, with a Banbury head. For polystyrene the BiVO. Rpm for 5 minutes at 40 and 205 ⁰ C. dispersed in polystyrene, heated to 316 ⁰ C. and held rpm for 15 minutes at 100th For ABS, the BiVO ₄ was rpm for 5 minutes at 40 and 205 ⁰ C. dispersed in the ABS, heated to 260 ⁰ C. and held rpm for 10 minutes at 100th The lack of stability was indicated by darkening.

♦♦ The washing step to remove NaNO was used during manufacture this sample not carried out.

The results of Table III show that the absence of sodium nitrate in the gel prior to calcination has an adverse effect on the heat resistance of the wiamut vanadate made by calcining the gel. Taking into account the results of Table II and III it is clear that the control of the sodium nitrate content is essential in the gel before calcination Datée for producing a high-quality pigmentary Wismutvana-, especially if one wishes to heat resistance for use in the pigmentation of plastics.

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example By combining the following ingredients in a T-Miecher

a mixture was made:

(i) 4.872. kg Bi (NOj) ₃ .5H ₂ O, dissolved in 12.78 1 A, ON HNO ₃ and diluted with 51.1 1 of water, and

(ii) 9.3 kg of V ₂ O _{5 dissolved} in 31.94 liters of water containing 3.27 kg of NaOH and dissolved with 51.1 liters of water to a solution of sodium vanadate plus sodium hydroxide.

The mixer had an inner diameter of 0.3 cm-

for the bismuth nitrate opening, 0.488 cm for the sodium vanadate

opening and 0.488 cm for the exit. The bismuth nitrate occurs

("leg ¹¹ ) entered the shaft /. The solutions were in about 15 minutes mixed with a pressure of approximately 1.05 kg / cm applied across the tee. Sufficient HNO ₃ was added to component (i) or aqueous NaOH to component (ii) so that the pH of the mixture of the two materials was about 1.5-2.0. The mixture was transferred to a 170-1 tank containing 26.6 liters of water adjusted to pH 2.2 _{with HNO 3.} The tank contents were stirred for a few minutes, then the pH was adjusted to 3.2 with 2, ON NaOH. The contents were stirred for 15 minutes, filtered, washed with 76 liters of water and filtered again. The bismuth vanadate gel was collected from the filter cloth and stirred into a tank containing 31.8 kg of water, the water being adjusted to pH 3.1 _{with HNO 3.} The tank contents were ^{heated to 95 °} C. in about 40 minutes and kept at this temperature and a pH of 3.1 for 120 minutes. The isolated by filtration pigmentary Wiemutvanadatprodukt was 2 times ■ it each 76 1 of water and dried at 14O ⁰ C..

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- 20 - The above procedure was used 4 times to achieve a weight of approximately 12.2 kg Pigment repeated. 11.35 kg of the same were in 47.2 kg of water the

/ $ 67 g of 28% Fischer sodium silicate solution (40-42 ° b!), Dispersed by passing it through a caulin submicron homogenization system first at 140 kg / cm and then again at 350 kg / cm. Vuurda then heated the mixture to 9O ⁰ C., maintained at eieser temperature and adjusted with 2, ON NaOH to pH 9.6. A solution of 6.58 kg of 28% Fischer sodium silicate in 28.4 kg of water was added to the mixture over the course of 4 hours. Simultaneously, a dilute sulfuric acid solution (1.04 kg conc. Butefic acid in 32.3 kg water) was added to the mixture at such a rate that the pH of the mixture fell to 9.4 in about 45 minutes. The pH of the mixture was then increased to 9.6 with 2.0N NaOH. This

Procedure for controlling pH was over the 4 hour

} - Silicate addition time continued.

After the 4-hour addition, the pH uiurde with H.SO reduced to 9.0, maintained for 60 minutes and then vermindert.Während the mixture was kept at 9O ⁰ C. to 7.0 uiurde a solution of ¹ »7 kg of Al ₂ (SO ₄ ), 18H ₂ O in 6.8 kg of water

added over 10 minutes, whereupon the pH dropped to 2.0-3.0; it was increased to 6.0 in about 20 minutes with 2.0N NaOH. The product was filtered hot, washed 2MaI each with 115 1 water and dried at 15O ⁰ C.. Chemical analysis and electron micrographs showed that the pigment particles were coated with silica. The intensity and lightfastness measurements of the pigment before and after coating are shown in Table IV.

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- «Μ - table I V before coating after coating

Intensity; Light fastness ** s intensity; Lightfastness % green filter % fade-ometer ^ (as before coating) reflectance dark earth __ «__« _________

67.9 6.0 67.4 2.4

* % Change in reflectance after 44 hours of fade-ometer exposure

This example shows that the encapsulation of pigmentary Wisrnutvanadat in silica, the lightfastness is improved as determined by fade-ometer exposures.

Example 6__

A mixture was prepared by combining the following ingredients in a T-mixer with 1 mm internal diameter at 2.8 kg / cm within about 2 minutes: (i) 40.0 g Bi (NOj) ₃ .5 H ₃ O , dissolved in 200 ecm 2, ON ENT ₃ and with

Water diluted to 405 ecm, and
(ii) 15.16 g Na ₃ VO ^, dissolved in 200 ecm 2, ON NaOH and rinsed with water

diluted to 400 ecm.

Sufficient HNO ₃ was added to component (i) or aqueous NaOH to component (ii) so that the pH of the mixture of the two materials was approximately 1.5-2.0. The mixture was transferred to a 4-1 beaker containing 1200 ecm of water which had been adjusted to pH 3.0 _{with HNO 3.} The contents of the beaker were stirred for 1 minute, then the pH was adjusted to 3.4 with 0.5N NaCH. After stirring the mixture for 15 minutes, it was filtered, washed with 500 ecm of water and filtered again. The bismuth vanadate gel collected on the filter paper was divided into two equal samples A and B.

709881

Sample A was stirred into a beaker containing 800 ecm of water and the pH of the mixture was adjusted to 3.3-3.4 with HBr or NaOH. The mixture was heated to the boil for 90 minutes, the pH being kept at 3.3-3.4. The isolated by filtration Wismutv / anadatpigment was washed with 500 cc water and heated to dryness at 13O ⁰ C..

Sample B was calcined in an open crucible for 90 minutes at 400 ⁰ C..

Sample C was prepared by the procedure used for Sample A, except that 42.0 g instead of 40.0 g Bi (NO.) ,. 5H «0 were used.

Sample D was prepared as sample B, except that 42.0 g instead of 40.0 g of Bi (NOj) ₃ .5H ₂ O were used.

Sample E was prepared by combining the following ingredients in a T-mixer of 1 mm internal diameter at 2.8 kg / cm within about 2 minutes: (iii) 88.0 g NBi (N0 ₃ ) ₃ .5H ₂ 0, in 52 ecm conc. ENT ₃ and 400 ecm

Dissolved water, and then diluted to 800 ecm with water,

and (iv) 15.0 g of V ₂ O ₅ , in 600 ecm of water containing 53.0 g of NaOH, dissolved and then dissolved with water to 800 ecm

Diluted sodium vanadate plus sodium hydroxide.

Sufficient HNO ₃ was added to component (iii) or aqueous NaOH to component (iv) so that the pH of the mixture of the two materials was about 1.5-2.0. The mixture was transferred to a 4-1 beaker containing 1200 ecm of water, the

7 0 9 8 8 Γ /

- 25 -

with HNO, was adjusted to pH 2.2. The contents of the beaker were stirred for 1 minute, then the pH was adjusted to 3.3 with 0.5N NaOH. The mixture was stirred for 15 minutes, filtered, washed with 500 ecm of water and filtered again. The bismuth vanadate gel collected on the filter paper was placed in a beaker containing 500 ecm waeeer. The pH of the mixture was adjusted to 3.3-3.4 with HNO, or NaOH, then turned 90

Heated to the boil for a while, the pH value being constant

3.3-3.4 was held. The bismuth vanadate pigment isolated by filtration was washed with 500 ecm of water and heated to 130 ° C until it was dry.

Sample F was prepared as Sample B, in which 44.0 g instead of AO ₁ O g of Si (NO,) -. 5H-0 were used.

Sample C was produced like sample A, with 46.0 g instead of 40.0 g Bi (NOj), 5Η_0 being used.

Sample H was prepared as sample B, using 46.0 g instead of 40.0 g of Bi (NOj) ₃ .5H ₂ O.

Sample I was prepared by combining the following ingredients in a 1 mm ID mixer at 2.8 kg / cm in about 2 minutes: (v) 72.0 g Bi (NOj) ₃ .5H ₂ O, in 56 ecm conc. ENT ₃ and 400 ecm water

eer dissolved, then diluted to 800 ecm with water, and (vi) 19.0 g of V ₂ O ₅ , dissolved in 600 ecm of water containing 53.30 g of NaOH , then diluted with water to 800 ecm of a solution of sodium

vanadate plus sodium hydroxide diluted.

- 23 709881/0851

Sufficient ENT. was added to ingredient (v) or aqueous MaOH to ingredient (vi) so that the pH of the mixture of the two materials was about 1.5-2.0. The mixture was transferred to a 4-liter beaker containing 1200 ecm of water which had been adjusted to pH 2.2 with HNO2. The contents of the beaker were stirred for 1 minute, then the pH was adjusted to 3.3 with 0.3N NaOH. After stirring for 15 minutes, the mixture was filtered. The bismuth vanadate gel collected on the filter paper was stirred into a beaker containing 500 ecm of water and the pH of the mixture was adjusted to 3.1 with HNO or NaOH. The mixture was heated to the boil for 120 minutes, the pH being kept at 3.1. The isolated by filtration Wismutvanadatniederschlag was resuspended in 400 cc of water, the temperature was raised to 5O ⁰ C., the pH is raised to 8.0 and maintained for 10 minutes. The isolated by filtration Wiemutvanadatpigment was washed with 500 cc water and heated to 13O ⁰ C. Trockensein on.

Sample 3 was prepared by combining the following ingredients into one

a 1 mm T-mixer at 2.8 kg / cm for about 2 minutes

manufactured:

(vii) 72.0 g Bi (N0 ₃ ) ₃ .5H ₂ 0, in 56 ecm conc. ENT ₃ and 400 ecm

Dissolved water, then diluted to 800 ecm with water, and (viii) 15.0 g of V ₂ O ₅ , dissolved in 600 ecm of water containing 53.30 g of NaOH, then with water to 800 ecm of a solution of sodium vanadate plus Diluted sodium hydroxide.

Sufficient HNO ₃ was added to component (vii) or aqueous NaOH to component (viii) so that the pH of the mixture was about 1.5-2.0. The mixture was in a 4-1 beaker

transferred, which contained 1200 ecm of water which was adjusted to pH 2.2 with HNO2. The contents of the beaker were stirred for 1 minute, the pH was adjusted to 3.3 with 0.5N NaOH, the mixture was stirred for minutes, filtered, washed with 500 ecm of water and filtered again. The collected on the filter paper Wismutvanadatgel was calcined in an open crucible for 60 minutes at 400 ⁰ C..

The intensity and lightfastness of the above samples are given in the table V compared. table V Sample mole ratio, intensity; Light fastness *;

from Bi to VG. ~ % Green filter % fade ometer dark

be refiekta nz

4.5 6.4 8.0 14.5 4.7

6.4 7.9 10.0 12.5 / 15.1:

♦ + 8.0 ·

The data in Table V show that bismuth vanadate production by using molar ratios outside the limits specified here, the properties of the bismuth vanadate obtained and makes the product non-pigmentary as defined here.

aqueous 1.00 / 1.00 1.00 / 1.00 71.2 A. 1.05 / 1.00 1.05 / 1.00 69.0 C. 1.10 / 1.00 1.10 / 1.00 7 ?; 9 E. 1.15 / 1.00 1.15 / 1.00 74.2 G 0.90 / 1.00 0.90 / 1.00 61.7 I. ceicinated B. 75.0 D. 78.4 F. 78.2 H 76.4 3 54.9

7 0 9 8 8 * 1/0 8 5 * "i

- 76 -

example

The samples prepared in the above examples were also verified by reflectance spectra and differential thermal analysis measurements (DTA = "differential thermal analysis"). The results of these measurements, along with intensity values on colored strips, are shown in Table VI

70988 1/085

Table Vi

Beep. Sample increase in powder intensity; DTA ·} endothermic peaks; ⁰ C.. reflection units. . $ Green filter - from 450-525 nm reflectans

2 A 72 60.5 861 952

AC 71 74.4 944

6 F 75 78.2 936

6 E 80 73.9 867 927 937

* Samples were analyzed on a DuPont 900 thermal analyzer using Pt-Rh (13 %) ο thermal elements and platinum containers for macro samples «The sample size was

O ₀ 20 mg with 20.6 mg Al ₂ O ₃ or 15 mg with 15 mg Al ₂ O ₃ I the Al ₂ O, was supplied by the supplier as a reference. The experimental conditions were: heating rate = 3O ⁰ C./min; Room temperature to 1000 ⁰ C .; Atmosphere = 25 cc / min air.

-2G-

Example 6

By combining the following ingredients in a T-mixer

a mixture was made:

(i) 4.872 kg Bi (N0 ₃ ) ₃ .5H ₂ 0, dissolved in 12.78 g 4, ON HNO ₃ ,

then diluted to 51.1 l with water; and (ii) 9.3 kg of V ₂ ° 5 »dissolved in 31.94 l of water containing 3.27 kg of NaOH, then made into a solution with water to 51.1 l of water

Diluted sodium vanadate plus sodium hydroxide. The T-Miecher had an inner diameter of 0.3 cm for the bismuth nitrate opening, 0.488 cm for the sodium vanadate opening and 0.488 cm for the exit. The bismuth nitrate entered through the shaft. The solutions were mixed in about 15 minutes with a pressure of about 1.05 kg / cm applied across the tee. Sufficient HNO ₃ was added to component (i) or aqueous NaOH to component (ii) so that the pH of the mixture was about 1.5-2.0. The mixture was transferred to a 170-1 tank.

Water
led, which contained 26.6 l / which was adjusted to pH 2.2 with HNO2. The tank contents were stirred for a few minutes and then adjusted to pH 3.2 with 2.0N NeOH. After stirring for 15 minutes, the contents were filtered, washed with 76 liters of water and filtered again.

Six 100 g samples were suspended in 6 portions of 300 ecm of water each. The pH values of the suspensions were adjusted to the values given in Table VII by adding HNO or NaOH and kept at the stated pH value for about 15 minutes. The suspensions were then filtered, the gel removed and ^{calcined at 400 °} C. for 1 hour. The crystal phase, intensity and lightfastness were measured and are listed in Table VII.

709881/0851

- 28 -

table VtI Sample pH phase

Intensity? Lightfastness% green filter % fade-crossover. Dark reflection

A. 1 , 5 tetra & mono phase θ 2 , 0 monoclinic phase C. 2 , 5 η D. 4th , 0 ti ε 6th , 0 mono and 2. 8th , 0 mono and 2. I. «* So
09
OO ro
VO

53.3 31.9 71.6 8.0 73.0 8.6 7 5, '2 13.4 72.6 17.5 65.7 24.4

CX) CD CO

Claims (1)

Claims e (T) - Pigmented, bright cowslip yellow monoclinic Bismuth vanadate. 2 · - bismuth vanadate according to claim 1, which after uniform mixing with 90% by weight of BariuiBulfate in the visible spectrum of 450-525 nm shows an increase of at least about 65 reflectance units on a scale on which the barium sulfate has reflectance of 100 units across the entire visible spectrum. 3 · - bismuth vanadate according to claim 1 and 2, characterized in that that the increase in powder reflectance is at least about 70 units amounts to. 4.- bismuth vanadate according to claim 1 and 2, characterized in that it has such a light fastness in color that a reflectance drop of less than about 11 % _t, preferably less than about 7 % _f at 44-hour fade-ometer ^v - 'Exposure results. 5 bismuth vanadate according to claim 1 and 2, characterized in that it has such an intensity in color that a green filter reflectance of at least about 60 % _t, preferably at least about 64 % t, results. 6 · - bismuth vanadate according to claims 1 and 2, characterized in that it has such a light fastness in color that there is a reflectance drop of less than about 7 % with 44-hour fade-ohm-meter exposure, and its intensity in color is such that a crf filter reflectance of at least about 60 %, preferably at least about 64 %, results. - 30 - 709881/0851 ORIGINAL INSPECTED - Vi - 7 · - Process for the production of a pigmentary, luminous cowslip yellow, Moroclinic bismuth vanadates, thereby marked that one A. a solution of Bi (NO,),. 5H ₂ O in nitric acid with a solution of alkali vanadate in an aqueous base from the group of sodium and potassium hydroxide to precipitate one in one solution containing dissolved alkali nitrate suspended bismuth 3+ vanadate gels mixes, the molar ratio of Bi being too VO. is between about 0.95: 1.00 to 1.10: 1.00 and the normalities of the acidic and basic solutions prior to mixing are so set ω earth that the pH of the mixture between β tu / a 1.0-8.0; B. adjust the pH of the suspension to about 1.9-3.6; C. removed the gel from the suspension; D. Wash it with water until there is about 20 wt .- ^ or less alkali contains nitrate, based on the theoretical bismuth vanadate yield; and E. the gel cslciniert about 0.4-3 hours at a temperature of about 200-500 ⁰ C.. 8.- The method according to claim 7, characterized in that the molar ratio of Bi ⁺ to VO. "is between about 0.98: 1.00 to 1.02: 1.00. 9.- The method according to claim 7 and 8, characterized in that the pH in stage B is adjusted to about 3.3-3.5. 10.- Method according to claim 7 to 9, characterized in that to get noticed gel is washed with water until about 5-7 wt -% containing alkali metal nitrate.. - yt - 11.- Method according to claim 7 to 10, characterized in that the gel is about 1 hour at 380-460 ⁰ C. etuia calcined. 12 · - Method according to claim 7, characterized in that the molar ratio of Bi ³⁺ to VO ₄ ³ "is about 0.98: 1.00 to 1.02: 1.00, the pH of the mixture is etuia 1.5-2.0, the pH in stage B is adjusted to about 3.3-3.5, the gel with water up to a content of about 5-7% alkali metal nitrate and then washed for about 1 hour is calcined at a temperature of about 380-460 ⁰ C.. 13.- The method according to claim 12, characterized in that the Well, VO. is dissolved in aqueous sodium hydroxide. 14 · - Bismuth vanadate gel for conversion into pigmentary, monoclinic Bismuth vanadate produced by a process in which one A. mixes a solution of Bi (NO,), 5H ₂ O in nitric acid with a solution of Na3UO ₄ in sodium hydroxide to precipitate a bismuth vanadate gel suspended in a reading containing dissolved sodium nitrate, the molar ratio of Bi to VO. is between about 0.95: 1.00 to 1.10: 1.00 and the normalities of the acidic and basic solutions are adjusted prior to mixing so that the pH of the mixture is about 1.0-8.0; B. adjusts the PpH of the suspension to about 1.9-3.6; C. removing the gel from the suspension; and D ₉ this is washed on the theoretical Wismutvanadatausbeute with water to a sodium nitrate content of about 20 wt. ~% Or less based · - 32 - 7098ß1 / 0851 15, - The product, manufactured according to the method of claim 14, characterized in that the water remaining at the end of stage D is removed. The patent attorney * 7098 ^ / 085