EP1989263A1

EP1989263A1 - Barium sulphate

Info

Publication number: EP1989263A1
Application number: EP07704685A
Authority: EP
Inventors: Sonja Grothe; Jochen Winkler
Original assignee: Sachtleben Chemie GmbH
Current assignee: Venator Germany GmbH
Priority date: 2006-02-21
Filing date: 2007-02-21
Publication date: 2008-11-12
Also published as: US7645334B2; JP5448461B2; CN101400744A; US20080314291A1; JP2009527452A; WO2007096385A1

Abstract

The invention relates to a method for producing barium sulphate having an organically modified surface, barium sulphate produced according to said method and to the use thereof.

Description

barium sulfate

The present invention is a process for the preparation of barium sulfate with an organically modified surface, the barium sulfate prepared by this process and its use.

Barium sulfate is used as an inert filler in many applications. The use of barium sulphate in polymeric materials has a positive effect on the properties of these materials. In contrast to other fillers, such as silicates or oxides, barium sulfate shows no interaction with the polymeric materials. However, the targeted adjustment of the interactions between filler and polymer is one way to adjust the properties of these composites. Therefore, it is desirable to be able to specifically modify the surface of barium sulfate particles in order to be able to adjust these interactions in a targeted manner.

EP-A-0293622, the technical teaching of which is fully incorporated herein by reference, discloses a process for producing barium sulfate having a chemoreactive surface by coprecipitation of barium ions with organic compounds. As organic compounds, for example, alkyl or aryl sulfates are used, which are optionally substituted with functional groups. This process has the disadvantage that the coprecipitation of barium sulfate and organic compounds, the particle size and the

Particle morphology of the precipitated barium sulfate particles are influenced. Moreover, there is no possibility with this method, the barium sulfate subsequently, that is, after the precipitation, to modify organically. Another

Disadvantage is then that the proposed organic compounds often tend to foam, which is a procedural problem. In addition, the concentration of the suspension suspensions produced in this way results in wastewater, which often has a high organic load. The object of the present invention is to overcome the disadvantages of the prior art.

In particular, the object of the present invention is to provide a process for producing barium sulfate with an organically modified surface, by which the particle size and the particle morphology of the precipitated barium sulfate are not influenced.

Another object of the present invention is to provide a process for producing barium sulfate having an organically modified surface, in which the barium sulfate is subsequently organically modified, that is to say after the precipitation.

Another object of the present invention is to provide a process for producing organically modified surface barium sulfate which prevents foaming by the organic compounds used for modification during precipitation.

Another object of the present invention is to provide a process for the production of barium sulfate with an organically modified surface which reduces the high organic load of the effluent from the concentration of precipitation suspensions.

According to the invention, the object is surprisingly achieved by the features of the main claim. Preferred embodiments can be found in the subclaims.

In this case, the objects are achieved by a method that allows to carry out the organic modification of the surface of the barium sulfate only after the precipitation of the barium sulfate. This procedure has the advantage that the particle formation in the precipitation of barium sulfate can be carried out in the usual way. That is, on the one hand, the Particle formation is not adversely affected by coprecipitates, but on the other hand it is easier to control the particle size and morphology of the barium sulfate particles.

The precipitation of the barium sulfate to be used according to the invention can be carried out by all methods known from the prior art. Barium sulfate is preferably used in a precipitation reactor for precipitating nanoscale particles, in particular a reaction cell for the ultrafast mixing of several reactants, for example of aqueous solutions of barium hydroxide and sodium and / or zinc sulfide and / or

Sulfuric acid, was produced. According to the invention, the barium sulfate is present after precipitation in the form of a precipitation suspension.

The barium sulfate used according to the invention is washed and concentrated, so that the wastewater produced is not organically contaminated. The barium sulfate is now in the form of a concentrated barium sulfate suspension. The preparation of the barium sulfate according to the invention can be carried out by processes known per se. According to the invention, the barium sulfate suspension is mixed with a barium component, so that a barium excess is formed. The barium component used may be any water-soluble barium compound, for example barium sulphide, barium chloride and / or barium hydroxide. The barium ions adsorb on the surfaces of the barium sulfate particles.

Then suitable organic compounds are added to this suspension with vigorous stirring and / or during dispersion. The organic compounds should be selected so that they form a sparingly soluble compound with barium ions. By adding the organic compounds to the barium sulfate suspension, the organic compounds precipitate with the excess barium ions on the surface of the barium sulfate.

Suitable organic compounds are compounds selected from the group of the alkyl and / or arylsulfonates, alkyl and / or aryl sulfates, alkyl and / or aryl phosphoric acid esters or mixtures of at least two of these compounds, wherein the alkyl or aryl radicals may be substituted by functional groups. Also, the organic compounds may be fatty acids, which may have functional groups. It is also possible to use mixtures of at least two such compounds.

For example, in the method of the invention:

alkyl sulfonic acid,

sodium polyvinyl sulfonate,

Sodium N-alkyl benzene sulfonate,

Sodium polystyrenesulfonate, sodium dodecylbenzenesulfonate,

sodium lauryl sulfate,

sodium cetyl sulfate,

Hydroxylamine,

Triethanolammonium lauryl sulfate, phosphoric acid monoethylmonobenzyl ester,

lithium perfluorooctane,

12-bromo-1-dodecanesulfonic acid,

Natium-10-hydroxy-1-decanesulfonate,

Sodium carrageenan, sodium 10-mercapto-1-cetane sulfonate,

Sodium 16-ceten (1) sulfate,

Oleylcetylalkoholsulfat,

Oleic acid sulphate,

9,10-dihydroxystearic acid, isostearic acid,

stearic acid,

Oleic acid.

The barium sulfate modified according to the invention can either be used directly in the form of the present aqueous paste or dried before use. The drying can be carried out by methods known per se become. The use of convection dryers, spray dryers, grind dryers, freeze dryers and / or pulsation dryers is particularly suitable for drying. However, other dryers are likewise usable according to the invention. Depending on the drying process, subsequent grinding of the dried powders may be necessary. The grinding can be carried out by methods known per se. The barium sulfate preferably has an average particle diameter of d 50 = 1 nm to 100 μm, preferably from d 50 = 1 nm to 1 μm, more preferably from d 50 = 5 nm to 0.5 μm, and is preferably dispersed to primary particle size before the organic modification.

The primary particles have a logarithmic particle size distribution with a median of d = 1 to 5000 nm, preferably d = 1 to 1000 nm, particularly preferably d = 5 to 500 nm with a geometric standard deviation of σ _g <1.5, preferably of σ _g <1, 4.

The inventively modified barium sulfate can be further treated after the orgnanischen modification with functional silane derivatives or functional siloxanes. For example, in the inventive

Method used:

octyltriethoxysilane,

Methyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-isocyanatopropyltriethoxysilane.

The barium sulfate modified according to the invention can be used in the field of composite materials, for example for improving the mechanical properties of plastics, preferably thermoplastics, thermosets and / or elastomers. In addition, the inventively modified barium sulfate can be used in polymeric materials as nucleating agents. Also, the crystallinity of polymeric materials is through the use of the inventively modified barium sulfate increases. In addition, it is used in paints and coatings, while also having a positive effect on mechanical properties and other properties such as glass transition temperature and chemical resistance. Further examples of fields of use of the barium sulfate modified according to the invention are: adhesives, composites in conjunction with metals or ceramic materials, cosmetics, synthetic fibers.

The process according to the invention for producing the surface-modified barium sulfate according to the invention has the following advantages in comparison to the prior art, in particular to the prior art disclosed in EP-A-0293622:

- there is no soluble barium; soluble barium is poisonous and therefore undesirable;

- there is no COD load of the waste water;

- less foaming is observed;

the particle size and morphology of the barium sulfate particles, that is, for example, whether cubic, platelet or spherical particles are formed, in the precipitation is easier to control, since the precipitation is not affected by coprecipitates;

the organic compound preferably precipitates on the barium sulfate surface, since the excess barium ions are deposited on the particle surface;

The subject of the invention is in detail:

A process for producing organically modified surface barium sulfate comprising the steps of: a) adding a concentrated barium sulfate suspension with a barium component and then b) adding organic compounds to the suspension.

a process for the production of barium sulfate with an organically modified surface, which comprises the following steps: a) addition of a concentrated barium sulfate suspension with a barium component, then b) addition of organic compounds to the suspension and c) aftertreatment of the organically modified barium sulfate particles with functional silane derivatives and / or functional siloxanes.

> A process for the production of barium sulfate with organically modified surface as described above, wherein

• the barium component in step a) is a water-soluble barium compound, preferably selected from barium sulphide, barium chloride and / or barium hydroxide;

The organic compounds in step b) are those which form compounds sparingly soluble with barium ions,

- The organic compounds are selected from the group of alkyl and / or arylsulfonates, alkyl and / or aryl sulfates, alkyl and / or Arylphosphorsäureester, wherein the alkyl or aryl radicals may be substituted by functional groups, and / or fatty acids which optionally have functional groups, or mixtures of at least two of these compounds;

the organic compounds are selected from: alkylsulfonic acid salts,

sodium polyvinyl sulfonate, Sodium N-alkyl benzene,

sodium polystyrene sulfonate,

sodium dodecyl benzene sulfonate,

Sodium lauryl sulfate, sodium cetyl sulfate,

Hydroxylamine,

Triethanolammoniumlaurylsulfate,

Phosphorsäuremonoethylmonobenzylester,

Lithium perfluorooctane sulfonate, 12-bromo-1-dodecanesulfonic acid,

Natium-10-hydroxy-1-decanesulfonate,

Sodium carrageenan,

Sodium 10-mercapto-1-cetane sulfonate,

Sodium 16-ceten (1) sulfate, oleyl cetyl alcohol sulfate,

Oleic acid sulphate,

9,10-dihydroxystearic acid,

isostearic,

Stearic acid, oleic acid, or mixtures of at least two of these compounds;

- The organic compounds are added with vigorous stirring and / or during dispersion to the suspension;

- The barium sulfate in step a) has an average particle diameter of dso = 1 nm to 100 microns, preferably from dso = 1 nm to 1 micron, more preferably from d ₅ o = 5 nm to 0.5 microns;

- The primary particles of barium sulfate in step a) a logarithmic particle size distribution with a median of d = 1 to 5000 nm, preferably from d = 1 to 1000 nm, particularly preferably d = 5 nm to 500 nm and a logarithmic particle size distribution with a geometric standard deviation of σ _g <1, 5, preferably of σ _g <1, 4;

- The organically modified Bariumsulfatpartikel in step c) are aftertreated with functional silane derivatives and / or functional siloxanes;

the functional silane derivatives and / or functional siloxanes are selected from:

Octyltriethoxysilane, methyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-isocyanatopropyltriethoxysilane, or mixtures of at least two of these compounds;

a barium sulfate obtainable by the process according to the invention for the production of barium sulfate with an organically modified surface;

a barium sulfate having an organically modified surface, wherein the barium sulfate has an average particle diameter of d ₅ o = 1 nm to 100 μm, preferably of d _δ o = 1 nm to 1 μm, particularly preferably of d 50 = 5 nm to 0.5 μm ;

Barium sulfate having an organically modified surface, the primary particles of barium sulfate having a logarithmic particle size distribution with a median of d = 1 to 5000 nm, preferably of d = 1 to 1000 nm, particularly preferably of d = 5 nm to 500 nm and a logarithmic particle size distribution a geometric standard deviation of σ _g <1, 5, preferably of σ _g <1, 4; Barium sulfate having an organically modified surface, the barium sulfate having been aftertreated with functional silane derivatives and / or functional siloxanes, wherein the functional silane derivatives and / or functional siloxanes are preferably selected from: octyltriethoxysilane, methyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ -Aminopropyltriethoxysilane, γ-isocyanatopropyltriethoxysilane, or mixtures of at least two such compounds;

- Use of the barium sulfate according to the invention for use in polymeric materials, preferably in composite materials;

Use of the barium sulfate according to the invention for use in polymeric materials, preferably in thermoplastics, thermosets and / or elastomers;

Use of the barium sulfate according to the invention for use in paints and inks;

Use of the barium sulfate according to the invention in adhesives, composites in connection with metals or ceramic materials, in cosmetics, and / or

Synthetic fibers;

Use of the barium sulfate according to the invention as nucleating agent in polymeric materials.

The invention is explained in more detail by the following exemplary embodiments, without restricting them to them:

Example 1 :

In a stirred tank, 500 g of platelet-shaped barium sulfate in 0.5 L of demineralized water (demineralized water) are suspended at room temperature. With a 0.1 molar barium hydroxide solution, a barium oxide is then adjusted so that a pH of 1 1 is achieved. In the strongly stirred barium sulfate suspension 25 g of sodium lauryl sulfate are added slowly. The suspension is then stirred for a further 30 min. Then the pH is adjusted slowly to 6.0 with 0.1 molar sulfuric acid and stirred for a further 15 min. The resulting product is then dried at 105 ° C. The carbon determination of the product gave a carbon content of 1.7%. The product differs significantly from the platelet-shaped barium sulfate used. The coated platelet-shaped barium sulfate is no longer wetted by wetting agent-free water.

Example 2:

In a precipitation reactor, barium sulfate is precipitated from one liter of 0.5 molar barium chloride solution and one liter of 0.5 molar sodium sulfate solution. The flow rates of the educts are 100 mL / min. The precipitate is filtered and washed to pH 6. The washed filter cake is dispersed in a dissolver at speeds of 1000 min ^-1 for 15 min and adjusted to a solids content of 30% with demineralized water .. During dispersion in the dissolver, a barium excess is adjusted by the addition of 0.1 molar barium hydroxide solution. That is, a pH of 12 is reached, then 23 g of oleic acid sulphonate are added to the suspension and further dispersed for 15 minutes, the suspension is washed to a pH of 9 and then brought to a pH of 0.1 with 0.1 molar sulfuric acid 6. The product is then freeze-dried and the barium sulfate produced is no longer wetted by wetting agent-free water.

Example 3:

In a stirred vessel 1000 g of a nanoscale barium sulfate having a primary particle size of d50 = 40 nm are suspended in 2 L of deionized water. This suspension is dispersed with a batch pearl mill using 1.2 mm glass beads at a temperature of T = 35 ° C. and an energy input of P = 40 W for 30 minutes. 0.3 molar barium hydroxide solution is added to the dispersed barium sulfate suspension with vigorous stirring, so that a pH of 1 1, 5 established. Then, the suspension is mixed with 100 g Oleylcetylalkoholsulfat, Na-SaIz, and stirred for a further 20 min. With 0.4 molar sulfuric acid, the pH of the suspension is then adjusted to 6.5. The product is then spray-dried. The carbon content of the product is 4.4%. After extraction in ethanol, a carbon content of 4.3% is determined.

Example 4:

The barium sulfate powder prepared according to Example 3 is used in an acrylate clearcoat to improve the mechanical properties of the paint. For this purpose, a millbase is prepared with the following composition: Macrynal SM 510 n: 42.3 parts by weight

Xylene / MPA 2: 1: 42.3 parts by weight

Barium sulfate: 55.0 parts by weight.

This millbase is dispersed on Skandex using 2 mm glass beads for 75 min. The dispersing fineness of the thus-dispersed millbase is <5 μm. The millbase was then diluted with hardener and adjuvant solution as follows:

Grinding paste: 39.4 parts by weight

MP: auxiliary solution: 18.8 parts by weight

Desmodur N75: 16.5 parts by weight Macrynal SM 510 n: 25.3 parts by weight.

Lacquered elevators with wet film thicknesses of 50 μm, 100 μm and 150 μm were produced on black glass plates and dried overnight. The remission of the dried lacquer layers are:

Wet film thickness remission 50 μm 0.17

100 μm 0.28

150 μm 0.42 The pendulum hardness of the thus modified clearcoat was increased by 10% compared to the unfilled clearcoat. The glass transition temperature of the clearcoat could be significantly increased by the use of the modified barium sulfate from T = 56 ° C to T = 70 ° C.

Example 5:

When used in a UV-curing parquet lacquer, the abrasion resistance is significantly improved.

Claims

claims

1 . Process for the preparation of barium sulfate with an organically modified surface, which comprises the following steps: a) addition of a concentrated barium sulfate suspension with a barium component and then b) addition of organic compounds to the suspension.

2. The method of claim 1, comprising the steps of: a) adding a concentrated barium sulfate suspension with a

Barium component, then b) addition of organic compounds to the suspension and c) aftertreatment of the organically modified barium sulfate particles with functional silane derivatives and / or functional siloxanes.

3. The method according to claim 1 or 2, characterized in that the barium sulfate in step a) has an average particle diameter of dso = 1 nm to 100 .mu.m, preferably dso = 1 nm to 1 .mu.m, more preferably dso = 5 nm to 0 , 5 microns.

4. The method according to at least one of claims 1 to 3, characterized in that the primary particles of barium sulfate in step a) a logarithmic particle size distribution with a median of d = 1 to 5000 nm, preferably from d = 1 to 1000 nm, more preferably from d = 5 nm to 500 nm and a logarithmic particle size distribution with a geometric standard deviation of σ _g <1, 5, preferably of σ _g <1, 4 have.

5. The method according to at least one of claims 1 to 4, characterized in that it is the barium component in step a) is a water-soluble barium compound, preferably selected from

Barium sulfide, barium chloride and / or barium hydroxide.

6. The method according to at least one of claims 1 to 5, characterized in that it is in the organic compounds in step b) are those which form sparingly soluble compounds with barium ions.

7. The method according to at least one of claims 1 to 6, characterized in that the organic compounds are selected from the

Group of alkyl and / or arylsulfonates, alkyl and / or aryl sulfates, alkyl and / or aryl phosphoric acid esters, where the alkyl or aryl radicals may be substituted by functional groups, and / or fatty acids which optionally have functional groups, or mixtures from at least two of these compounds.

8. The method according to at least one of claims 1 to 7, characterized in that a method for organic modification of the surface of barium sulfate particles, wherein the organic compounds are selected from: alkylsulfonic acid salts, sodium polyvinyl sulfonate, sodium N-alkyl-benzenesulfonate, sodium polystyrenesulfonate, sodium dodecylbenzenesulfonate,

Sodium lauryl sulfate, sodium cetylsulfate, hydroxylamine sulfate, triethanolammonium lauryl sulfate, phosphoric acid monoethylmonobenzyl ester, lithium perfluorooctane sulfonate, 12-bromo-1-dodecanesulfonic acid, sodium 10-hydroxy-1-decanesulfonate, sodium carrageenan, sodium 10-mercapto-1-cetane sulfonate, sodium 16-ceten (1) sulfate, oleyl cetyl alcohol sulfate, oleic acid sulfate, 9,10-dihydroxystearic acid,

Isostearic acid, stearic acid, oleic acid or mixtures of at least two of these compounds.

9. The method according to at least one of claims 1 to 8, characterized in that the organic compounds are added with vigorous stirring and / or during dispersion to the suspension.

10. The method according to at least one of claims 2 to 9, characterized in that the organically modified barium sulfate particles in step c) aftertreated with functional silane derivatives and / or functional siloxanes become.

1 1. Method according to at least one of claims 1 to 10, characterized in that the functional silane derivatives and / or functional siloxanes are selected from: octyltriethoxysilanes, methyltriethoxysilanes, γ-methacryloxypropyltrimethoxysilanes, γ-glycidyloxypropyltrimethoxysilanes, γ-aminopropyltriethoxysilanes, γ-isocyanatopropyltriethoxysilanes, or mixtures of at least two such compounds.

12. barium sulfate, obtainable by a process according to any one of claims 1 to 1 1st

13. Barium sulfate with organically modified surface, characterized in that the barium sulfate has an average particle diameter of dso = 1 nm to 100 microns, preferably from dso = 1 nm to 1 .mu.m, more preferably from dso = 5 nm to 0.5 microns.

14. Barium sulfate according to claim 13, characterized in that the primary particles of barium sulfate have a logarithmic particle size distribution with a median of d = 1 to 5000 nm, preferably from d = 1 to 1000 nm, more preferably from d = 5 nm to 500 nm and a logarithmic particle size distribution with a geometric standard deviation of σ _g <1, 5, preferably of σ _g <1, 4 have.

15. barium sulfate according to claim 13 or 14, characterized in that the barium sulfate is post-treated with functional silane derivatives and / or functional siloxanes, wherein the functional silane derivatives and / or functional siloxanes are preferably selected from: octyltriethoxysilanes, methyltriethoxysilanes, γ-methacryloxypropyltrimethoxysilanes, γ- Glycidyloxypropyltrimethoxysilanes, γ-aminopropyltriethoxysilanes, γ-isocyanatopropyltriethoxysilanes, or mixtures of at least two such compounds.

16. Use of a barium sulfate according to at least one of claims 12 to 15 for use in polymeric materials, preferably in composite materials.

17. Use of a barium sulfate according to at least one of claims 12 to 15 for use in polymeric materials, preferably in thermoplastics, thermosets and / or elastomers.

18. Use of a barium sulfate according to at least one of claims 12 to 15 in adhesives, composites in conjunction with metals or ceramic materials, in cosmetics, and / or synthetic fibers.

19. Use of a barium sulfate according to at least one of claims 12 to 15 as nucleating agent in polymeric materials.