FI69481C - ORGANIC PIGMENT MED FOERBAETTRAD OPTISK PRESTATIONSFOERMAOGA - Google Patents

Description

1 69481

The present invention relates to inorganic pigments whose optical performance in lacquer binders has been improved by treatment with organic excipients before or during final micronization.

In addition to other properties such as good weather resistance or non-lumpy dispersibility when mixed with lacquer binders, one important requirement for high quality pigments is high optical performance. An important optical performance of the pigment dispersed in the binder is because it determines the adequacy of the coating agent formed.

15 The measure of the optical performance of an inorganic pigment is, among other things, the relative scattering ability, which is the scattering ability of an unknown pigment relative to the reference pigment.

Accordingly, the present invention relates to pigments which, after mixing with a lacquer binder, have a high relative scattering ability.

In this case, the relative scattering capacity is determined in accordance with DIN 53 165, which is also known as the so-called harmaatah-namenetelmänä.

In the prior art, inorganic pigments are treated organically to modify their surface to provide compatibility with organic binder systems. By mixing the pigments with the lacquer binders, it is claimed that their dispersibility is improved in this way and wrinkle-free and high-gloss pin-30 coatings are obtained. Usually, the organic excipient is added to the pigment before or during the final treatment of the production process, in which case the addition takes place during the comminution of the pigment in a rod, ball or pendulum mill. Particularly high quality pigments are obtained by micronizing the so-called in shower-35 mills, e.g., air-jet or steam-jet mills.

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Numerous compounds are known as organic auxiliaries for surface modification. In addition to organosilicon compounds, polyols, alkene oxides, phenols, long chain fatty alcohols and fatty acid esters, alkanolamines have also been proposed for the organic treatment of Pigment-5.

Accordingly, U.S. Patent No. 3,345,187 describes the use of trialkanolamines and German Patent No. 2,442,678 describes the use of diisopropanolamines.

According to the method of DOS 1 792 022, triethanolamine is brought into contact with the pigment surface by the so-called during double steam jet milling. It is also known to use salts of alkanolamines and organic acids such as lactic acid (DE Patent No. 1,271,862) or salts of benzoic acid (U.S. Patent No. 3,172,772).

But the proposed measures are either technically cumbersome and expensive, or the pigments formed, despite the obvious improvements compared to organically untreated inorganic pigments, do not meet the most stringent quality requirements in terms of scattering-20 ability. This is especially true for pigments post-treated with Fungi and Al 2 O 2.

It has now surprisingly been found that inorganic pigments with improved Siron tack can be prepared in a simple manner by treatment with <O-bis-aminoalkylcarbinols before or during final micronization.

Accordingly, the present invention relates to inorganic pigments having improved scattering ability, coated with o (CU-bisaminoalkylcarbinols of the general formula:

P 0H

I / R3

N- (CH 2) -C- (CH 2) -M

35 ^ Ί 2 \ h4

^ B

3 6 S 4 81 wherein m and o can be from one to three, R is hydrogen or a C 1 -C 4 alkyl residue and, R 2 and R 2 are the same or different C 1 -C 4 radicals, wherein R 1 and R 2 are and R 1 and R 2 may also optionally be linked via hydrocarbon chains containing heteroatoms, and a process for their preparation by coating the pigments with the above compounds before or during final micronization, preferably using R 10 O 2 or titanate-based, optionally inorganically post-treated white pigments.

The new pigments are particularly suitable for pigmenting lacquer binders.

The pigments are contacted with 0.1-4%, preferably 0.2-1% organic excipient. Preferred -bisaminoalkylcarbinols for this purpose are 1,3-diamino-2-propanols of the formula:

R1 0H R

\ I ^ 3

N-CH0-CH-CH0-N

20 R ^ \ R

R 2 is R 4 wherein R 1, R 2, R 2 and R 2 are the same or different C 1 -C 4 residues, wherein R 1 and R 2 and R 2 and R 2 and R 2 may also be optionally linked via heteroatom-containing hydrocarbon chains.

In this case, 1,3-bisdimethylamino-2-propanol is particularly preferred.

The method of adding an excipient to the pigment is known per se.

It does not matter whether the excipient is mixed with the wet filter cakes, pastes or suspensions formed in the pigment production before drying, or whether it is added in a suitable manner, e.g. by spraying or dripping, to the dried feed immediately before the final grinding. When using steam jet milling, the excipient can be added immediately to the jet mill upon feeding.

4 69481

The method is applicable to all inorganic pigments. Particularly advantageous results were obtained with TiCl 2 and titanate-based white pigments. Optionally, the pigments can be post-treated inorganically.

According to the invention, pigments with excellent scattering ability are obtained.

According to the invention, rutile or anatase-shaped TiCl 2 pigments prepared according to both the sulphate process and the TiCl 2 combustion process can be treated.

The following describes in detail the surface treatment of inorganic post-treated TiO 2 pigments with an organic excipient according to the invention.

After several preliminary stages, e.g. oven clinker, which is ground and sorted. The fines 15 are optionally post-treated with e.g. Al (OH) 2, Fungi or TiCl 2. The treatment can take place in suspension according to different process variants. The water is then removed inorganically from the post-treated pigment slurry as a rotary filter and washed at the same time. The filter medium 20 from this first rotary filter can be remixed with water and passed to the second rotary filter. This second rotary filter material is washed once more with water and dried using belt dryers or spray dryers. The pigments are then comminuted by grinding in either compression mills such as a Raymond, ball or hammer mill or a jet mill, e.g. an air jet mill or a steam jet mill. The organic excipient of the invention may be contacted with the pigment at various points before or during micronization. For example, the excipient can be mixed with the material of the second rotary filter after washing and before drying. It can also be added to the dried material immediately before micronization, e.g. by spraying. In another treatment, the compounds used according to the invention are added to the steam or air in connection with the feed to the jet mill. It is also possible to add an excipient to the pigment at different points in the manufacturing process.

The relative scattering ability of the pigments according to the invention was tested in accordance with DIN 53 165, which is also known as the so-called harmaatahnamenetelmänä. All pigments were tested uniformly using a pigment volume concentration (PTK) of 15% by volume. Inorganically post-treated rutile pigment Bayer-Titan R-KB-2 was used as a reference pigment. Test conditions other than this standard were not used.

The following examples illustrate the preparation of the pigments of the invention.

Example 1

The rutile-15 TiO 2 pigment prepared by the sulfate process, hereinafter referred to as pigment A, was inorganically treated with 0.8% SiO 2 and 2.5% Al 2 O 2 and dried after the usual washing and filtration steps. The pigment was sprayed with 0.4% 1,3-bisdimethylamino-2-propanol and micronized in a superheated steam steam mill. Determination of the relative scattering ability for the standard pigment (Bayertita R-KB-2 gave a value of Sr = 108.

Comparative Example A

The starting material of Example 1 was sprayed with 0.4% of a conventional organic excipient which was a reaction support from trimethylolpropane and 3.5 moles of ethylene oxide (see Example 7a DOS 1 467 442) and micronized under the conditions of Example 1. Determination of the relative scattering capacity for Bayertita (S) R-KB-2 ^ gave Sr = 97. It appears that the use of 1,3-bisdimethylamino-2-propanol under the same manufacturing conditions improved the relative scattering capacity by 11 units compared to the conventional organic excipient.

Example 2

The starting material of Example 1 was sprayed with 0.6% 1.3-35 bidimethylamino-2-propanol and micronized according to Example 1 6 69481. The relative scattering ability gave a value of Sr = 108.

Comparative Example B

The starting material of Example 1 was sprayed with 0.6% of the conventional excipient of Comparative Example A and micronized according to Example 1. The relative scattering ability gave a value of Sr = 96.

It can be seen from Example 2 and Comparative Example B that even when changing the amount of excipient, the use of 1,3-bisdimethylamino-2-10 propanol is more preferable.

Example 3

The starting material of Example 1 was sprayed with 0.4% 1,3-bisdimethylamino-2-propanol and micronized less intensively than in Example 1. The relative silencing capacity was Sr = 100.

Comparative Example C

The starting material of Example 1 was sprayed with 0.4% of the conventional excipient of Comparative Example A and micronized according to Example 3. The relative scattering ability was 20 Sr = 84.

Example 3 and Comparative Example C show that under other micronization conditions, it is preferable to coat the pigment 1,3-bisdimethylamino-2-propanol 11a for relative scattering ability.

25 Example 4

A TiCl 2 pigment having a rutile structure prepared according to the sulphate process, hereinafter referred to as pigment B, and which is a different so-called pigment. differs from pigment A due to calcination, was treated inorganically with 0.8% SiO 2 and 2.2% Al 2 O 2 and dried after the usual washing and filtration steps. The pigment was sprayed with 0.5% 1,3-bisdimethylamino-2-propanol and micronized according to Example 1. The relative scattering ability was found to be Sr = 108.

7 6 94 81

Comparative Example D

The starting material of Example 4 was sprayed with 0.5% of the conventional organic excipient of Example 1 instead of 1,3-bis-dimethylamino-2-propanol and micronized according to Example 4. The relative scattering ability was Sr = 101.

Example 4 and Comparative Example D show that the advantages of 1,3-bis-dimethylamino-2-propanol also become apparent when using other starting materials.

Example 5 The pigment B of Example 4 was post-treated as inorganic as in Example 4, with further wet milling as an aqueous suspension during the inorganic post-treatment. At the end of the inorganic work-up, it was washed, filtered and dried in the usual manner. Pig-15 was sprayed with 0.5% 1,3-bisdimethylamino-2-propanol and micronized according to Example 4. The relative scattering ability of the pigment was Sr = 112.

Comparative Example E

The starting material of Example 5 was sprayed with 0.5% of the conventional organic excipient of Example 1 instead of 1,3-bis-20 dimethylamino-2-propanol and micronized according to Example 5. The relative scattering ability of the pigment was Sr = 102. Example 5 and Comparative Example E show that also when using an additional grinding step, the advantages of 1,3-bisdimethylamino-25-2-propanol become apparent compared to a conventional organic excipient.

Claims (7)

1. Inorganic pigments having an improved spreading ability and coated with 0.2-1% by weight, based on the pigment weight, of an oL, tt'-bisaminoalkylcarbinol of the general formula R1 OH / R3 N '(CH 2) »- CH- <CH2) oN \ Wherein m and o may both have the value 1-3, R is a hydrogen atom or a C 1 -C 2 alkyl group, R 2, R 0, R 2 and R 2, which may be the same or different, denotes a C ^-C ^ group or R ^ and R ^ and R R and R R may be joined to each other via carbon chains which optionally contain heteroatoms. 2. Inorganic pigments according to claim 1, characterized in that the pigment is a white pigment based on TiO2 or titanates, which is subjected to an inorganic post-treatment if required. 3. Inorganic pigments according to claim 1 or 2, characterized in that the cL, IU-bis-amino-alkylcarbinol is 1,3-diamino-2-propanol of the formula R 1 OH, R 1 CH-CH 2 -N R 2 R 4 wherein R 2, R 2, R 2 and R 2, which may be the same or different, represent a C 1 -C 2 group or R 2 and R 2 and R 2 and R with each other via hydrocarbon chains, which may contain heteroatoms. 4. Inorganic pigments according to any of claims 1 to 3, characterized in that the OL, Ct-bis bisaminoalkylcarbinol is 1,3-bis-dimethylamino-2-propanol.