WO1983001780A1

WO1983001780A1 - Post-treated anatase pigment and utilization thereof

Info

Publication number: WO1983001780A1
Application number: PCT/CH1982/000119
Authority: WO
Inventors: Sa Viscosuisse
Original assignee: Lerch, Erwin
Priority date: 1981-11-19
Filing date: 1982-11-15
Publication date: 1983-05-26
Also published as: EP0093733A1

Abstract

The anatase pigment contains a phosphated zirconium compound; said compound is applied by precipitation and has a molar relation of P to Zr ranging from 2:1 to 1:1. The phosphated zirconium compound verifies the general formula (ZrO)xHyP2Oz, wherein 1 <= x <= 2, y >= 2 and z >= 7.

Description

Aftertreated anatase pigment and its use

The invention relates to an aftertreated anatase pigment and its use for matting synthetic fibers, in particular polyamide fibers.

In most cases, synthetic fibers are known to be matted with titanium dioxide pigments. Despite the higher refractive index and the lack of a catalytic effect on photooxidation e.g. of polyamide fibers, rutile pigments are hardly used for matting synthetic fibers, since the thread-guiding elements are damaged too quickly by their pronounced abrasion effect.

For the matting of synthetic fibers almost exclusively rutile-free A natas pigments are used, which are characterized by a considerably lower abrasion effect than rutile pigments, which result in a bluish white due to the stronger remission of the blue-violet light (a property that can be emphasized by the smaller crystal size) and due to the considerably smaller absorption of anatase in the long-wave compared to rutile UV range does not affect the fluorescence excitation of the optical brighteners. These indisputable advantages of untreated anatase pigments are now at least in contrast to the catalytic effect of anatase modification on the photooxidation of, for example, polyamide when used for matting polyamide fibers as a serious disadvantage. When using untreated anatase pigments for matting polyamide fibers, it is therefore usually necessary to add light stabilizers, such as manganese compounds, to the polyamide. By selecting suitable manganese compounds in appropriate concentrations, which are generally adapted to the respective degree of matting, even in the case of deep matt fibers, the matting pigment can no longer impair the light stability of the fibers. Such light stabilizers based on manganese can, however, be partially or completely washed out in wet finishing operations such as washing out, dyeing, etc., as a result of which the light stability of the polyamide fibers suffers considerable losses. On the other hand, an increase in the manganese concentration in matted polyamide fibers can have an unpleasant impact on their whiteness, which sometimes only becomes noticeable after finishing operations such as hot air fixing, alkaline washes, etc.

There has been no shortage of efforts to cover the photocatalytic reactivity of the anatase pigment with an inorganic aftertreatment which is fixed in insoluble form on the pigment surface and thus to ensure better light stability of the polyamide fiber, even at low manganese concentrations. Known embodiments of such post-treatments consist in the striking of suitable aluminum and / or silicon compounds, such as, for example, AlO (OH), aluminum silicates or phosphates on an anatase pigment, manganese compounds (eg phosphates) also possibly being co-precipitated. In the latter case, it is possible to dispense with the addition of manganese in the production of polyamides with pigments treated in this way.

It is also known to treat titanium dioxide pigments with a zirconium phosphate compound. DE-AS 12 02 422 relates to a titanium dioxide pigment with a small amount of an insoluble water-containing zirconium phosphate to improve the chalk resistance of coloring, enamel and lacquer films.

FR Patent 2,206,363 and EP Patent 0 008 101 further relate to a process for producing zirconium-containing titanium dioxide pigments with improved resistance to chalking and gloss retention by striking a zirconium compound and aluminum and / or silicon compounds on the titanium dioxide pigment.

Such anatase pigments which have been post-treated in accordance with the prior art with aluminum and / or silicon compounds, in particular on the basis of aluminum oxide hydroxide, now have a number of disadvantages which, in turn, severely restrict their usability for matting staple fibers. This applies especially to the production of deep matt polyamides. So is the dispersibility in water for anatase pigments with after-treatments of the above Type difficult, and for the production of stable aqueous suspensions of such pigment types very special measures are usually required, such as the use of polyphosphates in a case-optimized concentration, extraordinary pH settings, etc. Use in deep matt polyamide fibers can achieve the same or even higher degrees of raw white than with untreated types of anatase, give manganese and aluminum and / or silicon compounds surface modified anatase pigments with this use in most cases a fiber with poorer degree of raw white or unwanted yellow or red cast. The most serious disadvantage of the anatase pigments aftertreated with aluminum and / or silicon compounds, which also affects the manganese-free types, is the fact that they can lead to the complete failure of anti-yellowing additives, which work perfectly in the presence of untreated anatase types work. Such anti-yellowing formulations are generally additive mixtures which are used in particular for deep matt polyamide fibers and reduce the yellowing of the polyamide when hot-air-fixing textile fabrics and in use. The effect of such yellowing or At least for the hot air fixation of deep matt polyamide 66 fibers, the use of post-treated anatase pigments of the type mentioned can almost completely eliminate oxidation protection systems.

It has now been found that these disadvantages can be avoided with the product according to the invention, an anatase pigment aftertreated with zirconium phosphates, and that, in addition, unexpected and particularly advantageous properties occur in the synthetic fibers, preferably polyamide fibers, matted with the product according to the invention, ie better whiteness (raw and after hot air fixing), better lightfastness and surprisingly considerably better lightfastness of dyeings.

The invention relates to an aftertreated anatase pigment which contains a precipitated zirconium phosphate compound with a molar ratio P: Zr between 2: 1 and 1: 1. This pigment is particularly suitable for matting synthetic fibers, preferably polyamide fibers.

The composition of the zirconium phosphate compound precipitated on the anatase pigment corresponds to the following general formula (ZrO) _X H _Y P ₂ O _Z , in which l <x <2, y> 2 and z> 7. Particular preference is given to the composition (ZrO) with zirconium phosphate compound H ₂ P ₂ O ₇ post-treated anatase pigments.

The product according to the invention contains 0.5 to 10%, preferably 2 to 6%, of the zirconium phosphate compound, the water content in the product which can be driven off by annealing at 800 ° C. generally making up no more than 10% of the amount of zirconium phosphate contained therein. The TiO ₂ pigment can additionally contain 1000 to 3000 ppm Mn from a manganese compound which has also been precipitated.

The invention further relates to the use of this post-treated anatase pigment for matting synthetic fibers, in particular polyamide fibers. With Anate pigments aftertreated with zirconium phosphates allow the preparation of aqueous suspensions in the exact same and known manner as is the case with untreated types of anatas. A particularly salient property of the products according to the invention is their absolute compatibility with anti-yellowing additives in deep matt polyamide fibers, with an increase in the anti-yellowing effect when hot air being fixed compared to the comparison product with untreated anatase being observed. By using the aftertreated anatase pigments instead of untreated anatase types, a significantly increased light resistance is achieved in polyamide 66 yarns with the same manganese concentration and, surprisingly, the lightfastness of dyeings is also considerably improved. The polymer contains 0.02 to 20% and the finished thread 0.02 to 3% of the post-treated anatase pigment.

It can also be mentioned that, unlike the TiO ₂ pigments aftertreated exclusively with a zirconium phosphate compound, unlike the TiO ₂ pigments aftertreated with aluminum and / or silicon compounds, they have no adverse effect on the yellowing when hot air fixing threads and textile fabrics made of matted polyamides.

The invention is explained below purely by way of example. To produce the product according to the invention, it is of course also possible to start with anatase pigment which has been lattice-stabilized, for example with antimony. Before or during the precipitation of the zirconium phosphates, manganese (II) phosphates can also be deposited on the TiO ₂ pigment in a manner known per se. Example 1 and Comparative Examples

Product production and characterization according to the invention

In the following example, the parts mean parts by mass and, in the case of concentrations, the percentages always mean percentages by mass.

To 2000 parts of an intensely stirred 25% aqueous suspension of a commercially available untreated anatase pigment (99% TiO ₂ ) with an Sb content of less than 0.01% and an average particle size of

The solution of 42.06 parts of tetrasodium diphosphate decahydrate Na ₄ P ₂ O _{7 became} 0.28 μm. 10 H ₂ O in 500 parts of water were added. After stirring for 10 minutes, the intensely stirred batch is given the cold, freshly prepared and possibly concentrated aqueous solution of 30.4 parts of zirconium (IV) oxychloride octohydrate ZrOCl ₂ ^. 8 H ₂ O is quickly incorporated and the mixture is stirred for another hour. The aftertreated anatase pigment is then filtered off, washed with deionized water completely free of chloride and the filter cake is dried at 120-150 ° C. The product is finally milled with a flapping wing mill.

In order to quantitatively analyze the loading of the post-treated pigment with zirconium phosphates and to be able to determine the exact composition of the precipitated zirconium phosphate, the procedure was as follows: The amounts of tetrasodium diphosphate and zirconium oxide chloride listed in the above post-treatment example Precipitation in the absence of TiO _{2 was} carried out in exactly the same way, the precipitated zirconium phosphate was filtered off, washed free of chloride and dried at 120 ° C. to constant weight. Through wet chemical Zr and P determination and independent determination of the

Zr content by means of the X-ray fluorescence spectrum (calibration series with ZrO ₂ ) and determination of the loss on ignition was able to determine the composition of the zirconium phosphate obtained in this way as the formula ZrP ₂ O ₇ . H ₂ O must be ensured accordingly. With ZrP ₂ O ₇ . H ₂ O is of course at least formally equivalent to the formulation as (ZrO) H ₂ P ₂ O ₇ . With the untreated anatase pigment, which had served as the starting material in Example 1, a calibration series was now made by intimately mixing with 1.0, 2.0, 4.0 and 6.0% of the pure ZrP ₂ O ₇ . H ₂ O produced. These samples and the product according to the invention were measured in the X-ray fluorescence spectrometer. In this way, the zirconium diphosphate content in the post-treated anatase pigment was determined to be 3.9%.

The product according to the invention behaves exactly the same as the untreated anatase pigment used as the starting material in the known “4-hour test” and in the production of a 25% aqueous allspice suspension. Table 1 is based on the reflectance measurements on pressed powder samples of the product according to the invention, the untreated starting material and on two commercially available, conventionally aftertreated anatase pigments (both free of manganese).

Example 2 and Comparative Examples

There were three deep matt polyamide 66 types A, B and C in a laboratory autoclave of 30 1 content made of 13.65 kg of hexamethylene diammonium adipate with the addition of 0.7 mol% acetic acid, 228 g (= 1.9% based on that finished deep matt polyamide 66) one of the anatase pigments specified below, 0.98 g manganese oxalate dihydrate (= 0.0081%), corresponding to 25 parts manganese 1 million parts of polyamide and an additive mixture which serves as yellowing protection for the polyamide and consists of sterically hindered phenol antioxidants and an organophosphorus compound. The manganese salt was mixed with the 50% aqueous hexamethylene diammonium adipate solution and the respective matting agent in the form of a 25% aqueous suspension was introduced into the autoclave 30 minutes after the pressure of 18 bar had been reached.

The three polyamides A, B and C differ only in the type of matting agent used. It contained:

Variant A: 1.9% of an inventive, with 4%

Zirconium diphosphate ZrP ₂ O ₇ . H ₂ O-treated anatase pigment according to Example 1

and the comparative polyamides of

Variant B: 1.9% of a commercially available untreated

Anataspigments (it is the same type that was used to manufacture the product according to the invention)

and

Variant C: 1.9% of a commercial manganese-free anatase pigment, not according to the invention and aftertreated with aluminum and silicon compounds, with a TiO ₂ content of approx. 95%. Microscopic examination of 6 µm thick cross sections of the polymer strand showed the most uniform and finest pigment distribution in the case of variant A.

Threads having a titer of 44 dtex and consisting of 13 individual fibrils were produced from the polyamide A produced with the product according to the invention and from the polyamides B and C used for comparison purposes by melt spinning and subsequent stretching. Circular hoses were made from the three types of thread.

The whiteness of the knitted fabrics, expressed as% remission at 440 nm (based on the remission value of freshly smoked magnesium oxide equal to one hundred), was in each case in the original state and after the knitted fabrics had been fixed in air at 210 ° C. for 20 s and 56 s ( = Yellowing test) measured. In addition, the percentage loss of tensile strength of the three thread types after 300 h exposure was determined in the XENOTEST device type 450. Finally, the knitted fabrics of the three types of thread, which had been heat-set, were washed out in air at 210 ° C. for 20 s and dyed in the usual way with 0.3% Lanasyn Pure Red RL. The color-light fastness of the dyed knitted fabrics was determined in accordance with SNV regulation No. 195'809 determined (xenon arc light).

The results are summarized in the following table.

Claims

1. Aftertreated anatase pigment, characterized in that it contains a precipitated zirconium phosphate compound with a molar ratio P: Zr between 2: 1 and 1: 1.

2. Aftertreated anatase pigment according to claim 1, characterized in that it contains a zirconium phosphate compound of the general formula (ZrO) _X H _Y P ₂ O _Z , in which 1 ≤ x> 2, y> 2 and z> 7.

3. Post-treated anatase pigment according to claim 2, characterized in that the zirconium phosphate compound (ZrO) is H ₂ P ₂ O ₇ .

4. Aftertreated anatase pigment according to claim 1, 2 or 3, characterized in that it contains between 0.5 to 10%, preferably 2 to 6% of the zirconium phosphate compound.

5. Aftertreated anatase pigment according to claim 4, characterized in that it contains 1000 to 3000 ppm Mn from a co-precipitated manganese compound.

6. Use of aftertreated anatase pigment according to claims 1 to 5 for matting chemical fibers, in particular polyamide fibers, characterized in that the polymer contains 0.02 to 20% and the finished thread 0.02 to 3% of the aftertreated anatase pigment.