GB2102419A - Dustless metallic soap granules - Google Patents

Abstract

Dustless particulate granules of metallic soaps are prepared by treatment of particles of such soaps in aqueous suspension by the addition thereto of a composition comprising an oleaginous material, such as a mineral oil, silicone oil, oleic acid or a liquid plasticizer. The oil may be added during the preparation of the soap from the corresponding fatty acid, or to the already formed material,

Description

SPECIFICATION Dustless metallic soap granules The dusting of powders has been a problem since the earliest times. Industrial emphasis on the control of dust begin in the early years of the coal and the flour-milling industries where the dust was not only a health hazard, from the point of view of ingestion of the dust by breathing, but an explosion and fire hazard as well. In modern plants, particularly those in which pigments or additives are processed for the paint and plastic industries, and most particularly with respect to those substances that exhibit high dusting tendencies, the dust evolved is a constant source of annoyance and danger in the plant. In recent years the necessity of complying with various governmental regulations in the polluation control area as well as others has made the provision of suitable dust control means a matter of considerable urgency.

Particularly, in the handling of certain metallic stearates such as barium and cadmium stearates, which are highly toxic and at the same time have an intense proclivity to dust, the elimination of dusting is critical to effect safe handling.

Consequently, many attempts have been made to bind the dust in some manner and to control it to some extent. For example, attempts have been made to allay dust by misting water in the air so as to maintain an excess of humidity in the area.

Oils have also been used around coal dust to alleviate the problem. Such methods are inapplicable where metallic stearates and other powders are processed by the very requirement that the pigments be dry.

Thus, where dry particulate dusting powders are routinely processed, vacuum systems are used to suck the dust-laden air out to a collection means, such as an air filter, Cottrell precipitator, or the like. In this regard, it might be owrth noting that a monumental effort has been directed towards compositions suitable for coating air filters and other dust collection means to entrap dust more effectively and to permit the operation of the dust separation means over relatively long periods of time.

The instant invention is directed to a method for preventing the formation of dust in the production of metallic soaps, thus dispensing with the requirements of complicated and increasingly more sophisticated and expensive dust collection apparatus.

The present invention is directed to the preparation of dust-free metallic soap granules which may be handled freely and spread in relatively thin layers without exhibiting dusting.

Summary of the invention The instant invention makes possible conventient handling of the most high-dusting metallic soap material by offering a choice of embodiments of a simple process, easily incorporated in existing processing facilities, any of which embodiments effectively suppresses or essentially negates the normally-high-dusting characteristic of the metallic soap material without appreciably affecting its free-flowing nature or changing its primary particle size.

In accordance with the present invention, dust generating metallic soaps are treated with a composition comprising an oleaginous material.

The oleaginous material can be a mineral oil, silicone soil, oleic acid, or it can be a liquid plasticizer such as dioctyl phthalate or epoxidized soybean oil.

The components can be compounded according to generally known procedures and the treatment of the dust generating materials with the treatment composition carried out by several diverse embodiments, including spraying, pouring on or in situ admixture. Preferably, however, the treatment will be carried out by adding the oil at the conclusion of the reaction in which the metallic soap is formed.

The metallic soap particles treated in accordance with the present invention can be dried employing any of the conventional drying procedures, such as fluidized bed drying.

Detailed description of the invention The present invention relates to a method for treating dust prone metallic soap materials to provide dustless, free-flowing powders. In addition, the present invention results in the highly advantageous effect of providing clean, uniform particles.

The invention is applicable to the various metal soaps of higher fatty acids. Illustratively, zinc, barium, cadmium, and calcium stearates, palmitates, oleates and the other known metal soaps can be treated in accordance with the present invention. However, the present invention is particularly advantageous in the preparation of dustless, free-flowing calcium stearate granules.

The oleaginous material is added in the proportions of up to about 20% by weight of the metal soap. The use of an amount of from about 3% to about 16% is preferred for optimal results.

The treated granular metal soaps can be employed wherever the untreated granules have been employed. Thus, they can be utilized in various applications in the polymer industries.

Illustratively, they are useful as lubricants and stabilizers in vinyl compositions and as mold release agents in various molding procedures.

The surprising and significant improvements afforded by the practice of the present invention are provided by adding the composition containing the mineral or silicone oil to the metallic soap during the production of the latter or by adding the mineral or silicone oil to the already formed metallic soap material. The products which result from the treatment disclosed herein are free-flowing, dustless materials and are completely clean to the eye and to the touch.

The following Examples are for pusposes of illustration only and are not to be construed as limitative of the present invention.

Example 1 In a mechanical Mixer, 1 500 g of deionized water, 284 g of stearic acid (1 mole) and 37 g of lime (0.5 moles) were introduced and the mixture was heated to 90 C while agitating at 1 800 rpm.

The producf was cooled to room temperature after agitating at 90CC for twenty minutes.

Mineral oil (Exxon 355) 60 g was then added under continued agitation. The agitation was stopped after 30 minutes and the product was filtered and dried in a fluidized bed dryer to a granular dust-free product.

Example 2 Fifteen hundred grams of deionized water were heated to 65-700C in a 4000 cc beaker equipped with a mechanical stirrer. Lime (37 g, 0.5 moles) was then added followed by a gradual addition of stearic acid (284 g, 1 mole) in about 5 minutes. The mixture was agitated at 70--7 5 OC for one and one-half hours. Mimeral oil (50 g) was then added under continued stirring. Agitation was stopped after 1 5 minutes and the granular product was recovered by filtering and drying.

Example 3 Granular non-dusting calcium stearate was produced following the procedure described in Example 1 using 11.75% of mineral oil instead'of 16%.

Example 4 Granular non-dusting calcium stearate was produced by following the procedure described in Example 2 using 11.75% of silicone oil (Dow200) in place of 14.3% of mineral oil.

Example 5 Calcium hydroxide (18.5 g, 0.25 mole) was stirred with 1000 ml of deionized water and the temperature of the mixture was raised to 60 OC in about 15-20 minutes. Oleic acid 141 g, 0.5 mole) was then gradualiy added with continued stirring in about 30 minutes. The reaction temperature was raised to 630C and maintained for 90 minutes. The temperature was then raised to 680C and held for 60 minutes. The product was filtered and dried to obtain analytically pure (IR analysis) granular calcium oleate.

Example 6 Calcium hydroxide (18.5 g, 0.25 mole) was added to 750 ml of deionized water and the mixture was stirred and heated to 65 CC. Palmitic acid (128 g, 0.5 mole) was then added with continued agitation in 30 minutes. The reaction temperature was maintained at 65-66 for 120--150 minutes. Mineral oil (5 g) was added and stirred for 10 minutes. The product was filtered to collect granular calcium palmitate.

Analytical results confirm essentially 100% conversion.

Example 7 Calcium hydroxide (37.0 g, 0.5 mole) and water (1000 ml) were heated to 70-720C under agitation. Stearic acid (276 g, 1 mole based on the acid number) was added in about 30 minutes, under continued agitation and the temperature of the mixture was maintained at 72 OC for 90 minutes. Mineral oil (10 g) was then added and stirring was continued for 10 minutes. The product was collected by filtration and dried to obtain non-dusting granules of calcium stearate.

Analytical results confirm 100% conversion.

Example 8 Barium hydroxide monohydrate (94.7 g, 0.5 mole) was stirred in 1200 ml of deionized water.

To this mixture stearic acid (276.0 g, 1 mole based on the acid number) was added. The mixture was stirred and heated to 750C. After 60 minutes of reaction at 750C, 10.0 gms of mineral oil was added and the agitation was continued for 10-1 5 minutes. The product was filtered and dried to obtain granular barium stearate.

Example 9 Citric acid (0.0005 moles, 0.1 g), Cd(OH)2 (73.3 g, 0.5 mole) and stearic acid (276 g, 1 mole based on the acid number) were added to 1 500 ml of deionized water at room temperature. The temperature of the mixture was raised to 650C under agitation and was maintained at that temperature for 60 minutes. Mineral oil (10.0 g) was added and agitation was continued for another 10-1 5 minutes. The product was filtered and dried to obtain granular cadmium stearate.

Example 10 Formic acid (1.0 g, 0.02 moles), CdO (64.4 g, 0.5 mole) and stearic acid (276.0 g, 1 mole based on the acid number) were added to 1 500 ml of deionized water. The mixture was stirred and the temperature was raised to 800C in about 30 minutes. The color of CdO starts fading as the reaction proceeds and complete colorless cadmium stearate is obtained after 120 minutes of reaction at 800C. Oleic acid (10.0 g) was then added and the stirring was continued for further 10--15 minutes. The granular cadmium stearate obtained was filtered and dried.

Example 11 Citric acid (0.5 g, 0.0026 mole), Mg(OH)2, (29.1 5 g, 0.5 mole) and stearic acid (276 g, 1 mole based on the acid number) were added to 1 200 ml of deionized water at room temperature.

The mixture was agitated and the temperature was raised to 65-660C. The product becomes quite viscous after about 1 5-20 minutes. It was cooled at this point to 56-580C by adding cold water. The temperature was again gradually raised to 790C and held for 60 minutes. Oleic acid (10 g) was added and stirring was continued for another 10-1 5 minutes. The product was filtered and dried to obtain granular magnesium stearate.

Example 12 Citric acid (0.5 mg, 0.0026 mole), ZnO (40.8 g, 0.5 mole) and stearic acid (276 g, 1 mole based on the acid number) were added to 1 500 ml of deionized water at room temperature. The temperature of the mixture was raised to 750C and maintained at that temperature for 90 minutes. Oleic acid (10 g) was added and stirring was continued for another 10-15 minutes. The product was filtered and dried to obtain zinc stearate granules.

Example 13 Ba(OH)2.8H2O (33.3 g, 0.106 mole) and stearic acid (69.0 g, 0.25 moles based on the acid numbet) were added to 600 mi of water of 2000 ml beaker equipped with a mechanical stirrer.

The mixture was stirred and the temperature was raised and held at 750C for 20 minutes. Cold water (600 ml) was added to bring the temperature down to 50-550C. Citric acid (0.1 g, 0.0005 moles), Cd (OH)2 (47 g, 0.32 moles) and stearic acid (165 g, 0.60 moles) were added to the above mixture and the temperature of the mixture was raised to 650C and maintained at that temperature for 60 minutes. Mineral oil (10.0 g) was added and stirring was continued for another 1 5 minutes. The product was filtered and dried to obtain granular barium/cadmium mixed stearates in the molar proportion of 1:3.

Example 14 Zinc oxide (20.4 g, 0.25 mole), citric acid (0.5 g, 0.0026 mole) and stearic acid (138 g, 0.5 mole) were added to 1 500 ml of water in a beaker equipped with a mechanical stirrer. The mixture was stirred and the temperature was raised to 700C. Calcium hydroxide (18.3 g, 0.25 mole) was then added under continued agitation.

Stearic acid (183 g, 0.5 mole) was then added and the temperature of the mixture was maintained at 700C for 60 minutes. Silicone oil (5.0 g) was added and stirred for another 10-1 5 minutes. The product was filtered and dried to obtain granular calcium/zinc mixed stearates in the molar proportion of 1:1.

Claims (9)

Claims

1. A method for the preparation of granular, dust-free metallic soap materials which comprises treating metallic soap material particles in aqueous suspension by the addition of an oleaginous composition to said aqueous suspension.

2. A method according to claim 1 wherein the oleaginous composition is present in the proportions of from 1 to 20% by weight of the metallic soap particles.

3. A method according to claim 1 or 2, wherein the oleaginous composition comprises a mineral oil.

4. A method according to claim 1 or 2, wherein the oleaginous composition comprises a silicone oil.

5. A method according to claim 1 or 2, wherein the oleaginous composition comprises a liquid plasticizer.

6. A method according to claim 6 wherein the oleaginous composition comprises a liquid plasticizer is dioctyl phthalate or epoxidized soybean oil.

7. A method according to any one of the preceding claims, wherein the metallic soap material is calcium stearate, zinc stearate, barium stearate, cadmium stearate or magnesium stearate.

8. A method according to claim 1 substantially as described in any one of the Examples.

9. A method for the preparation of granular, dust-free calcium stearate which comprises treating calcium stearate particles with a composition comprising 3% by weight of mineral oil.