DE1592905A1 - Process for treating pigments - Google Patents

Description

PATINTANWXLTI DR. E. WIEGAND DIPL-ING. W. NIEMANN -j c η y η η r DR. AA. KÖHLER DIPL-ING. C. GERNHARDT I 3 3 4 C? U 0

MONKS HAMIURO

phone: 555 476 8000 MÖNCHEN 15, October 12, 1966

TELEGRAMMEi KARPATENT NUSSIAUMSTRASSE 10

12831/66 Pe

Laporte Titanium Limited
London (England)

Process for treating pigments

The invention relates to the treatment of pigments and, more particularly, to the treatment of a Titanium dioxide pigment to improve its dispersibility in an organic or aqueous medium.

According to the invention there is provided a method of treating a pigment in which the pigment particles with a surfactant which is a monoester or a diester or a mixture of two or more these esters obtained by treating the reaction product of ethylene oxide and an alcohol or alkylphenol with o-phosphoric acid can be obtained, has, brought into contact. Advantageously, the surface-active

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Means a mixture of honoester and a diester of one of these Reaction product with o-phosphoric acid.

The ester is advantageously a compound of Pormel:.

RO ^ (CH ₂ CH ₂ O) _n 0 ■ .... ""-'- ^ P ² ^ · (I)

■ - '■■■. , 0H OH

RO - (CH ₂ CH ₂ O) _n

(II)

.in. which R 'is an alkyl radical having 8 to 20 carbon atoms or an alkylphenyl radical in which the alkyl radical'8 to Contains 20 carbon atoms, and η is the average universal number of the mole of ethylene oxide, which corresponds to one mole of ROIj. the reaction » received: are, represent. Preferably η is a number between 1 'and 50th. .

Pigments "treated" according to the method of the invention ^:

include titanium dioxide, lithopon, barite white (eariun

sulfate), zinc oxide, chrome yellow, phthalocyanine, barium carbonate, sirconium dioxide, aluminum oxide and silicon dioxide. The titanium dioxide to be treated can be anatase, rutile, or a composite pigment or colored pigment containing titanium dioxide. If the pigment is anatase or rutile, there are preferably small numbers of one on the surface of the particles

, or more hydrated oxides, e.g. 3. Hydrogenated aluminum oxide, a hydrogenated oxide of titanium, or hydrated silicon dioxide are present

The particles of the pigment are preferably with a Treatment agent treated in liquid state. The deal. medium, whether solid or liquid, in a suitable solvent, e.g. ethanol, acetone, water or xylene, dissolved be, "or it can be in a dispersion in Porn or, if it is a liquid it can olint. 3feraün:. &;;. ar-turn ^ will.

The treatment cuts are generally sour: however, if he \ rlinsciiu, their acidity can be changed by adding

■ ^ eutralisationsmittel, such as. B. an Alkalilivdrssyd, Ammonia or an amine, before, during or after the su the pigment, are neutralized.

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The method according to the invention can for example -. to the pigment particles which are obtained in the production of titanium dioxide by hydrolysis of a solution of titanium sulfate or another titanium salt and which are used in the calcination of the aqueous precipitated titanium dioxide. A slurry with water is prepared from the calcined particles, the slurry is subjected to re-classification, the hydroclassified slurry is filtered to obtain an aqueous slurry. "To give pulp, ier pulp · .ii- ~ dried and the dried particles are finally ground, for example in a jet mill. The particles in the hydroclassified slurry can. Optionally with one or more hydrated oxides, such as e.g. or a slurry of the pigment (before or after coating the surface) in water or another suitable liquid, e.g., acetone; or on the dried pigment before, during or after the final milling step.

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The method according to the invention can e.g. Find as well .on pigment obtained dur ⁴ ch the vapor phase oxidation of titanium tetrachloride application. The particles thus obtained, which may optionally be coated with one or more of the hydrated oxides indicated above, are preferably present in the form of a suspension in an aqueous medium or an organic liquid when treated according to the method of the invention.

If the treatment agent is in the form of a solution or Dispersion is applied, becomes the solvent or dispersant then removed from the treated particles. The treatment agent is "either as such or in! Torrn a solution or dispersion, preferably a paste, a slurry or a slurry of the pigment in water. • Mixing should be done in order to achieve a.

to achieve uniform treatment of the pigment particles. . It has been found that using a paste mixer3 the treating agent is uniformly distributed in a pigment slurry within up to 15 minutes. That treated Pigment is then, for example, at a temperature of ■ dried at 120 C and then in a hammer mill, or ground in a jet mill.

009887/1612

The pigment particles to be treated must be after. the implementation of any work process (z. B. calcination) which, when carried out after treatment according to the invention, destroy the effect of the treatment agent would be treated according to the method of the invention.

The amount of the treatment agent, with v / hich the pigment particles are brought into contact is, advantageous hafterwti ·· awischen 0.05 part by weight Ji and 5 _f 0 Gev / .; 1, preferably 0.1 (jw .-? 6 to 1.0 wt. Ji of the untreated pigment.

According to the invention, a pigment is also provided, whose particles with a surface-active agent with ' a mono or a diester or a mixture of two or more of these esters, advantageously one ionoester and a diester formed by the reaction of o-phosphoric acid with ν the reaction product of ethylene oxide and an alcohol or a phenol, advantageously a compound of the formula (i) or (II) can be obtained.

According to the invention is also a paint or? a varnish provided the one. Containing pigment according to the invention. th. Paints which contain a pigment according to the Invention has been treated, have an improved shelf life. Or can stability. '

show little or no change in viscosity and have a reduced tendency to gelation during storage at _4.

The invention is illustrated by the following examples, in which the percentages are based on weight »· explained in more detail.

In the examples of the '! Percentage of gloss "of an air-dried acrylic resin paint containing 37 parts by weight jS a titanium _r dioxydpigmen ^ e was measured as follows · Bas reflectance of a light beam, the black standard to a plate or tile appeared was measured , where is the angle of incidence

power of the ray was 45 and the reflexivity / measured in a plane which had the incident ray and the incidence perpendicular on the point of incidence, and being at a point on the plane so it was measured that the line connecting this point with the 3-point incidence, nit de: incidence perpendicular forms an angle of 45 °. A film of the paint containing the pigment was applied to a Gellophanblatt (registered Viarenzeichen) applied iJid das

one
Reflectivity / ray of light shining on the PiIm

measured as described.

After that, the value for the "Percentage of Glance 3" was des

Painting

Reflectivity of the paint film in _c * Reflectivity of the paint film '"

ß ORIGINAL

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In the examples, the opacity of an air ■;

dried AcrylharE _ans trich containing Titandioxydpigment of 37 wt .- # Lethoae after which that US-G-Allonen in the publication of the American Society for Testing Iaterials I-D 1738-602, issued I960 ,, with the proviso by. British gallons replaces Me, v / o dies zutrci, described isv, definitely. Opacity is therefore the number of square feet over which a UK gallon of paint can be evenly distributed to produce a contrast ratio of 0 = 0.8, the contrast ratio being defined in the ASTM publication.

The dispersibility of each pigment sample in V.'asser mir de by using an "Andreason pipette" v / ie, it follows:

The sample vrarde au eir.er 2 Gev. ^r . -J'igen solution of ammonia in demineralized vrassor to give a pigment dispersion with a concentration of 20 g / l. The dispersion was then left to stand for 30 minutes and transferred to a settling cylinder, after the time required for the particles with a Stoke's diameter of more than 5 minutes to settle bxl ± the bottom of the sampling on.2 (calculated according to Stoke's Law), a known volume of the dispersion was removed from the bottom of the zone and evaporated to dryness. From the weight dec

009887/1612 bad original

Residue can .the concentration of the particles with a diameter of 5 p. or less that remain in the dispersion are calculated and plotted as a percentage of the original concentration. The results indicate the relative dispersibility of the samples in water. ·

The compounds of TomeIn (I) and (II), as used in the examples, are referred to by their trade names “G-afac” with a subsequent reference to the type of ester under consideration. The table below shows the average molecular weight of the / mixture of ϊίοηο and diesters (eaten by the increase in the boiling point of benzene) and the phosphate content (measured as wt .- ^ PpO ₁ -).

Mixture molecular weight> 5 P0O5

RE 610 ·. 1750. 8th

EM 710 335 5.

RS 610 1350 10

RS 710, 2460 7

PE 510 1070 7

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: - ίο -

Example 1 .

A sample of anatase titanium dioxide pigment was surface-coated with 0.75% by weight of hydrating and 2.0% by weight of hydrated aluminum oxide, calculated as SiO ₂ and AlpO, on the content of the untreated pigment. After coating and washing to remove any soluble products from the over-eye process, the resulting slurry was drained to form a slurry containing 50% by weight pigment. The pulp was divided into portions. Various known treating agents were added to some portions of the rope in varying proportions and the agents which were to be used according to the invention were added to the other portions of the rope. r.enge was mixed in a paste mixer for 10 minutes, dried at 120 ° G, and passed through an i-liqueur mill ("Micropulverizer'SHaramermuKi: manufactured by Pulverizing Machinery Ltd.).

The relative dispersibility of the samples in .V / ater was wi ;: using the pipette Andreason method measured. In Table I below, samples 1 to 9 contain different amounts of known treatment agents and samples 10 to 21 contain different amounts of the treatment agents according to the invention. The treatment agents of samples 1 to 9, which are solids, were added in the form of a concentrated aqueous solution. The treatment agents according to the invention, the liquids afn </ # »yrdfn a If such added ■ '' ■ '00Μ · 7 / 1β12 " ⁿ "

- li -

Table I. ICr. Addition of dispersibility

1 0.1> liatriuciphosphate 90, -

2 $ 0.5 "92.3

3 liO Ji "92.3

t. 0.1 ?> Iiatriunliexe-E-phosphate 90.8,

5 0.5 Ϊ "93.2

6 1.0 '/ "90.2

7 0.1 i 'tri-natriur.-o-T) phosphate 90, Λ

8 G, £ 5 "92.4

9 1.0 γ. >'SS, 5

10 ■ 0.1 ',' Gafac RH 61C '92.6

11 ^ C, 5 ι '"93.5

12 1.0 · ;: «.33.5

1; 0.1 "üafac Rl ·: 71C 94, Γ

1.1 0.5 \ 1 "34.3

15 1.0 ^ ^lf 95.6

16 0.1 i '. uafac Ri 610 93.6

17 0.5 Γ "? 6.0

18 1.0 Ji "S6.3

19 0.1 Ji Ga-rcLO RS 710 93.5

20 x 0.5 55 ' ^IS 36.4

21 1.0 £ ^{! I} 37.0

Gafac? J2 610 is an i ™ commercially available Misil.u-ij of an I'Ionoester -geni-.ß cornel (I) ur-c. of a diester ^ cnä. /. T'omel (II), in which H. MhnMch is Gafac RI-I 710 a 1-Iischling, in v / which represents an all-lphenol residue with higher liolelculariev.-icht, and - ". S 61G v.:id IS 'represent mixtures, in. Velc.:en K represents an Allianolresr.

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- 12 Example 2

A rutile titanium dioxide pigment was surface-coated with 0.4 hydrated silicon dioxide, 1.75 wt ·, to dos v / aßserlösliche Produlcte Übersucsverfahrens to remove ^ and Eizielung a slurry containing nil et \ / a 60 weight jS dewatered solids. Samples of this pulp were treated in accordance with the invention with a phosphate ester, as indicated in the following table II, by mixing in a paste-maker for 10 minutes. The paste containing the treated pigment was dried for 16 hours at 120.degree. C., the resulting drenched, treated pigment was ground in a jet mill and the products were polished to a shine in an acrylic glass Zedaor; 122X as described above. The Zor-troUe in Sabelle II was treated the same as that of others. Samples subjected except that no treatment agent was added prior to mixing in the paste mixer for 10 minutes.

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Table II '

Opacity (77.42 cm ² / 4.5461 1)

(square ft./brit.gall.) fo gloss

Control \ 407 '- 47

0.25 i BM 710 '436 .61

1.00 fo RS 610 436 ■ '* 64

1.00 fo RS 710 443 63

Example 3

Another sample of rutile titanium dioxide pigment was surface-coated and washed as described in Example 2 "to give a pigment slurry having a solids content of about 60 % by weight. The treating agent Gafac RS 610 and a second sample the same treatment agent to which aqueous ammonia had previously been added in order to achieve a pH value of 7.3, added ^ both samples were added at 1 wt

_ Treatment agent treated on the basis of the weight of the pigment. These samples and a similar sample of untreated pulp were dried, ground and their opacity and gloss / were measured in Bedacryl 122X, as described in Example ^% 2. The results are shown in Table III below.

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Table III

Opacity (77.42 cm ² / 4.5461 1) £ gloss

. · '(Square ft./.brit.gall.)

Control 436 66

1 $> RE 610. 437 72

1 £ RE 610 487 73

(neutralized)

Example 4

This example explains the improved durability in the can (can stability) as paint of the one according to the Invention treated pigment contains.

A rutile titanium dioxide pigment was made with 1.1 parts by weight of hydrated silicon dioxide, 1.5 parts by weight of hydrated titanium dioxide and 1.5 parts by weight of hydrated aluminum oxide (calculated as SiO ₂ , titanium dioxide and Al ₂ O ^ on a weight basis of the untreated pigment) (this pigment is hereinafter referred to as "A") is surface-coated and is with. Surface-active agents according to. Invention as described in Example 2 treated.

With the treated pigment "ein.Anstrich .wurde the following u usa.Tnmensetzung prepared: .... ''.

009807/1612

15B290B

litanic oxide 21.8

Calcium carbonate, 16.5

Anti-sham agents 0.1

Cellulose-containing protective colloid 12.5

Sodium Pyrophosphate Dispensing Agent 2.5 *

Pungicid ■ "0.2

Polyvinyl acetate / octyl acrylate synthetic polymer emulsion 31.4

Coalescing Solvent 2.1

Water '12.9

The paint was prepared by stirring the pigment into a mixture of anti-foaming agent, protective colloid and dispersing agent with a little water and subsequent halide in a Cowles art oil for 15 ounces for 20 minutes. The remaining ingredients sov, ie ^r ^ Rorden the remaining water

I '

then admitted.

Table IY below illustrates the. improved Stability (as indicated on the basis of the viscosity) nacli different periods of time, which by the application of surface

».Active means (referred to as PI 510 and RS 610) in accordance with the The invention has been achieved. PE 510 is a commercially available one Mixture of a monoester according to formula (i) and a diester

• _t according to formula (II), in which R represents an alkylphenyl radical .. '·

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Table IV

Type of pigment

A (control) A + 1 f » PE 510 A + 0.75 $ RS 610

N.

Viscosity at a shear extent of 180-200 Seic. "After storage time in days *

0 0 14th 28 56 4, • 7 7.1. 7.7 8, c 5, 4th 3.4 3.1 V 7
>, ' 5, 4.2 3.7 4.7 5, 3.8 3.1 3.3

example 5

I3in paint ^ the gQzSLZ the V / cise described in J3example A- was produced, with a content of treated pigment with different hens from Gafac 113 610 was three ionates at 40 ° C and then four i-ionates at 2.aur .iterr.pc-ratiir and then checked on a portable Perrcnti viscometer at a temperature Λ ^Γ οη 25 ° 0 and in areas of different .shear extents The structure was allowed to develop for a period of 30 minutes for each shear extent before reading the values.

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■ - 17 -

The drawing illustrates the decrease in the initial _{viscosity of paint 4} as the proportion of surfactant treated with pigment A increases, and the resulting labor saving required to keep the viscosity of the paint low enough for use . bring.

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Claims (11)

, ι ■ ■ claims 1. A process for the treatment of pigments, characterized in that pigment particles with a surface-active agent of a monoester or a diester or a 3-enic of two or more such esters obtained by treating the reaction product of ethylene oxide and an alcohol, or one Alkylphenol with orthophosphoric acid are available, brings in contact. 2. The method according to .inprueh 1, characterized in that that the pigment particles with a compound of the general !Formula RO - (CH ₂ CH ₂ O) _n 0. (D OH
or * ι RO - (CH ₂ CH ₂ O) _n 0 '* RO - (CHoCH ^ O) C OH in which R is an alkyl radical having 8 to 20 carbon atoms or an alkyiphenyl radical with 8 to 20 carbon atoms' in the alkyl radical and η is the average number of xols Ethylene oxide, which are reacted with one mole of ROH, inete- - special. a number between 1 and 50, represent, or with the mixture brings into contact. 009887 / t6 12 3. The method according to claim. 1 or 2, thereby identified, draws that the pigment particles with the surface-active Gown treated in liquid state. 4. The method according to any one of claims 1 to 3, characterized characterized that nan the Pignentteilciien with a solution of the surface-active agent, especially in ethanol, acetone, | Water or xylene. 5. * Method according to one of claims 1 to 3, characterized in that , characterized in that the pigment particles with a dispersion of the surfactant is treated in a liquid. 6. A method according to one of the Aneprttche 1 to 5, characterized in that the pigment part dal wan used with acidic einem- ^above: surfactant, obtained by adding. Alkali hydroxyl, Ammonia or arain before or after contact with the pigment is neutralized, treated. 7. The method according to one of the insprüoL-ε 1 to C, dc.au: eh. Characterized _K that the pigment particles are misclit with 'barrels to form a paste, a slurry or a slurry before treatment with the surface-active agent. 8. The method according to any one of claims 1 to 7, characterized s marked that «on-the pigment particles after the coating · by heating, especially at 120 ° C, dries. · .; . ■■ ORIGINAL BATHROOM 009887/1612 • - 20 · -. 9. The method naoh one of claims 1 to .8, characterized in that the pigment parts with an amount of about 0.5 "to 5.0 #, in particular 0.1 to 1.0 $, of surface -active agent, 'based on the weight of the untreated particles, treated. * 10. The method according to any one of claims 1 to 9, characterized in that the treatment of particles of titanium » dioxide or a hydrated ^ Ketall- on the surface * oxide containing titanium dioxide executes. 11. The method according to any one of claims 1 to 9 »thereby • characterized in that the treatment is carried out on particles of lithium, barium sulfate, zinc oxide, chrome yellow, phthalocyanine, barium carbonate, zirconium oxide, aluminum oxide or silicon dioxide . 009887/1612