HU187695B - Process for preparing white filler based on aluminium oxide - Google Patents

Abstract

Aluminium oxide based white filler comprising "retour powder" formed in the calcinating oven of the Bayer-type alumina manufacturing process, being either surface-treated or separated from the particles having a grain size above 5 microns, optionally in admixture with known additives, particularly zinc oxide or sulphur and/or a plasticizer, ageing retarder and/or accelerator. According to the invention there is also provided a process for the preparation of aluminium oxide based white filler which comprises (a) subjecting "retour powder" formed in the calcinating oven of the Bayer-type alumina manufacturing process to surface treatment with a solid or liquid agent; or (b) separating the "retour powder" formed in the calcinating oven of the Bayer-type alumina manufacturing process from the particles having a grain size above 5 microns; and, if desired, admixing the product obtained according to process (a) or (b) with known additives, particularly with zinc oxide, sulphur, and ageing retarder and/or an accelerator, and/or plasticizer. The advantage of the present invention is that the fillers obtained are cheap and when incorporated into rubber or plastics mixtures a significant improvement of the properties (e.g., tensile strength, abrasion, specific electric resistance, etc.) takes place.

Description

Fillers are commonly used in the production of natural or synthetic rubber-based rubber products and plastics. An important group of these is the so-called. black fillers

- the most prominent of which is carbon black - are sometimes difficult to use. so e.g. they are used in large volumes due to their low volume weight, which causes significant storage problems. A further disadvantage is that some of the rubber's very important properties, e.g. wear resistance is only marginally or insufficiently improved. In addition, the so-called "wedge" is widely used. white fillers which are essentially aluminum, potassium, sodium, barium, or magnesium-containing materials or silicates. The

No. 071,943 U. S. Patent No. 5,198,195 discloses clay-based fillers in which the alumina: silicic acid ratio is greater than 0.85 and contains 0.2 to 0.6% by weight of thiuram disulfide. The production of alumina-based white fillers, e.g. according to Hungarian Patent Application No. 147,411, it is accomplished by annealing aluminum hydroxide mixed at 300-750 ° C using a vaccine prepared separately from sodium aluminate. The disadvantage of the procedure is that

- as in Issue 147,411. It is apparent from the text of the Hungarian patent specification that only fillers with a particle size of less than 0.2 microns meet the requirements of the rubber industry.

Other known methods employ alumina formed by treating aluminum trichloride with superheated water vapor or aluminum hydroxide gels precipitated from aluminum sulphate with soda or sodium alumina. These materials have a number of serious disadvantages; Thus, they are very expensive, not sufficiently active, and are prepared with high acid and / or acid. they may also contain alkali losses and may contain impurities (such as manganese or copper) which catalyze the aging process of rubber and are therefore very harmful.

No. 157,406. According to Hungarian patent application, alumina powder, in particular alumina, having a particle size of 0.2 to 100 microns, treated with a solid or liquid agent, is used as filler. This has the disadvantage of depriving the precious alumina of aluminum production. It is an object of the present invention to provide fillers that achieve or exceed the properties of previously known materials using readily available and inexpensive materials.

In Bayer's alumina production, aluminum hydroxide is known to be converted into alumina in a calcining furnace. The dust from the furnace is settled in an electrostatic precipitator, where 70-75% of the alumina used for electrolysis and 25-30% of the so-called "retour powder", which is not used for electrolysis, is recovered. This powdered product is recycled to an aluminum hydroxide mixer at an earlier stage of manufacture. The disadvantage of this is that the pulverized material recycled in the process has to be re-dried and calcined, which results in a significant loss of energy, also taking into account circuses.

Surprisingly, it has been found that the above-mentioned "retour powder" trapped in the electrostatic precipitator and recycled into the prior art can be used to provide very favorable properties in the rubber and plastics industry.

The present invention relates to a process for the production of an alumina-based white filler by surface treatment of a "retour powder" formed in the calcination furnace with a solid or liquid agent in the Bayer alumina process, followed by the addition of known additives, preferably zinc. oxide, titanium dioxide, sulfur, accelerator and / or anti-aging agent.

The fillers produced by the process of the present invention are preferably applied after surface treatment. For the purposes of the present invention, it has a glow loss of 1 to 33% by weight, a molecular weight of 110 to 145, a specific weight of 2.5 to 3.0 g / cm ³ , an aluminum content of 36 to 60% and a hardness of 4.5 to 6.5 on the Mohs scale. retourport ". It is very preferable to use a "retour powder" having an annealing loss of 6-16% by weight, i.e. alpha, beta, gamma-alumina hydrate.

The surface treatment is preferably carried out with the solid or liquid agents already present in the rubber or plastic mixture. The surface treatment is preferably with stearic acid, an oil preferably an extraction oil or a spindle oil - organic silanol or silane, diethylene glycol, calcium stearate, dioctyl phthalate, N-phenyl-N'-isopropyl-p-phenyl diamine, diaminocyclohexyl P-naphthylamine, aldol-α-naphthylamine, alkylated phenol, 2-mercaptobenzimidazole or dichlorodifluoromethane or a mixture thereof.

It has been found that a mixture of naphthenic acid and triethanolamine, in which the naphthenic acid is present in an amount of from 10 to 30% by weight, provides a very favorable surface treatment in the amount of 0.1 to 10 parts by weight based on the amount of the surface treatment agent.

The surface treatment can be carried out very advantageously with a mixture of stearic acid, an oil, preferably an extraction oil or a spindle oil, an organic silane or silanol naphthenic acid and triethanolamine. The amount of agent used for the surface treatment is 0.1-8% by weight of the "retour powder".

The surface treatment may be carried out at room temperature or during heating, usually at a temperature of 20-80 ° C. The surface treatment can be carried out in standard homogenizers, but it can also be effected by applying the liquid agent from the nozzles or spray equipment to the surface of the "retour powder",

The "retour powder" processed as described above can be incorporated into the rubber or plastic mixture after mixing with known additives (accelerators, anti-aging agents, zinc oxide, sulfur, titanium dioxide, etc.). This has the advantage that less energy - 25-35% - is required to blend into the rubber.

The filler produced by the process of the present invention may be used alone or in combination with other known fillers.

The filler-21 obtained by the process of the present invention

With the aid of 187,695 materials, the properties of rubber or plastics can be very positively influenced. The best results are obtained with surface-treated "retour powder" based fillers, however, surface-treated "retour powder" released from particles having a particle size of less than 5 microns can be used. In the case of rubber, the tensile strength and hardness are greatly increased and the wear considerably reduced, which is particularly advantageous in the manufacture of shoes and tires. In addition to the natural-based rubber, the filler of the present invention can also be used successfully in mixtures of various synthetic rubbers (e.g., nitrile rubber, butadiene-styrene, etc.). A further advantage of the filler produced by the process of the present invention is that in many cases it reduces the use of expensive accelerators; it has been found that the "retour powder" based filler adsorbs the accelerating agents less than the previously known carbon black or other alumina based white fillers.

The fillers produced by the process of the present invention are incorporated into the PVC mass to reduce the tensile strength to a lesser extent than the known fillers, while at the same time reducing the wear and a very large increase in electrical resistance by several orders of magnitude.

The fillers produced by the process of the present invention can be used in a variety of applications in the rubber and plastics industry, e.g. car tires, car covers, shoe soles, gaskets, floors, covers, plates, molds, tubes, etc. manufacture.

In construction applications, the filler produced in accordance with the present invention incorporated into plastics has an excellent flame retardant effect, in contrast to conventionally used inert fillers (e.g. kaolin, chalk, quartz flour, calcium carbonate). In fact, the bound water content of the filler produced by the process of the present invention produces water vapor at a temperature of about 400 ° C, which suppresses the flame. The process filler of the present invention further improves electrical insulation and creep current.

The following examples further illustrate the invention without limiting it to the examples.

Example 1

8.5 kg of retour powder (loss of ignition 12.05%; specific gravity 2.6 g / cm ³ ; aluminum content 42%; mash hardness 5.0) were mixed with 1 kg of precipitated silicate in a homogenizer and , 2 kg of stearic acid, 0.25 kg of extraction oil, 0.03 kg of triethanolamine, 0.01 kg of naphthenic acid and 0.01 kg of silanol at 72 ° C.

Example 2

9.0 kg retour powder (loss on ignition 15.45%; particle size 88% 1-5 microns; specific gravity 2.8 g / cm ³ ; aluminum content 39%; hardness 4.9 on the Mohs scale) 0.4 kg of precipitated silica are mixed and the mixture is 0.2 kg of stearic acid, 0.32 kg of spindle oil, 0.02 kg of silanol (trade name "Si 69", product of Kalichemie Federal Republic of Germany) 0.02 kg of triethanolamine and 0.007 kg 75 kg of naphthenic acid in a homogenizer.

Example 3

A "retour powder" (9.4 kg) having the characteristics set forth in Example 2, 0.2 kg stearic acid, 0.3 kg extraction oil and 0.1 kg silanol (trade name "Si 69", product of Kalichemie Federal Republic of Germany) The surface was treated with a 72 ° C liquid mixture in a homogenizer.

Example 4

The procedure of Example 3 is accomplished by changing the price using 0.1 kg diethylene glycol, triethanolamine or naphthenic acid instead of silanol.

Example 5

9.5 kg retour powder (loss on ignition: 8.6%; particle size: 1-20 microns; aluminum content: 43%; Mohs-scale hardness: 5.2) in a homogenizer at 0.2 ° C: 0.2 kg surface treated with a mixture of calcium stearate, 0.3 kg dioctyl phthalate and 0.02 kg triethanolamine.

Example 6

The fillers prepared according to the previous examples and the known fillers (carbon black and precipitated silica) are blended with different gums and each characteristic is determined after vulcanization by standard methods.

The results are summarized in the following tables. Table I shows the composition of each rubber mixture (by weight); I.-IV. columns are mixtures of the fillers according to the invention, while columns V and VI. Column 2 gives the composition of the mixtures prepared with reference fillers for comparison. The test results are all. Table.

187,695

Table I

Ingredients: I II. III. ARC. V VI. Natural caoutchouc 10.0 10.0 10.0 10.0 10.0 10.0 Zinc Oxide 0.5 0.5 0.5 0.5 0.5 0.5 stearic 0.15 0.20 0.15 0.20 0.25 0.25 Example 1 extender 6.0 3.0 - - - - Example 3 extender - - 6.0 3.0 - - Type HAF nail - - - 3.0 5.0 - precipitated silica - 3.0 - - 5.0 Extraction oil 0.35 0.42 0.32 0.41 0.5 0.5 Anti-aging 0.10 0.10 0.10 0.10 0.10 0.10 Santoflex IP 0.20 0.20 0.20 0.20 0.20 0.20 MBTS 0.05 0.05 0.05 0.10 0.10 0.10 Vulkacit DPG - - - 0.05 0.05 CBS 0.10 0.10 0.10 0.05 - - Sulfur 0.17 0.17 0.17 0.15 0.15 0.15

III. Spreadsheet

Composition: I II. III. arc. 5 PVC gran. 100 100 100 100 DOP plasticizer 48.8 50 50 50 Stabilizer 2 2 2 2 Naftovin T-3 Example 5 2 2 2 2 10 extender Calcium carbo- 40 - - - soda and kaolin Calcium carbonate and 40 15 silica Untreated "retour powder", Example 2 starting 40 20 material - - - 40

II. Spreadsheet

Test results: I II. III. ARC. V VI. Tensile strength kg / cm ² 200 220 200 240 100 170 % Elongation at break 500 500 550 550 350 400 Shore A ° hardness 52 56 56 60 57 56 Permanent elongation% · 4 6 4 6 7 8 Circuit Breaker Sil. kg / cm ² 30-32 30-32 34-36 44-46 30-32 332-34 Schopper wear mm ³ 200-220 200 180 120 250 240 Young Modulus MPa / cm ² - 8.7 7.6 11.8 15.4 7.3 7.8

The above results demonstrate that the fillers of the present invention can improve tensile strength and hardness and significantly reduce the degree of wear. Comparative studies show that wear is reduced by almost 50%, which is particularly important in the manufacture of shoes and tires.

Example 7

The filler made from surface-treated "retour powder" according to Example 5 is processed into hard and soft PVC blends of various compositions and the properties of the resulting products 50 are compared with those of PVC blends containing known fillers by standard methods. In III. and Tables V and B respectively. and VI. Table 55 shows the measured results.

In III. and IV. for soft PVC, Table V and VI Table 1 refers to hard PVC.

ARC. Spreadsheet

test results: I II. III. ARC. Tensile strength kg / cm ² 146 118 116 125 100% modulus kg / cm ² 89 76 70 80 Wear Schopper mm ³ 325 522 537 430 Electrical specific resistance, Ohm x cm 3,410 ¹⁶ 3,210 ¹³ 6.5 10 ¹² 1 3-10 ¹⁴ Table V. Composition: I. II III. ARC. V VI. PVC softener ratio 91/5 91/5 91/9 91/9 91/9 91/9 Example 5 extender 20 50 - - - Calcium carbonate extender - 20 50 - - Silicon dioxide extender - - - 20 50

187,695

The following composition is prepared:

composition L IL HL LV?

Example 9

L7. Spreadsheet

test results: I II. III. ARC. V VI. Martens 5 shape stability C ° 60 74 52 55 50 54 Impact strength cmkp / cm ² 7.3 7.7 5.7 5.3 6.2 4.9 Tensile Strength cp / cm ² 345 262 222 196 240 170

The above results demonstrate that the fillers of the present invention can be used to produce plastic blends with significantly improved properties. With less reduction in tensile strength and a significant reduction in wear, 15 it is particularly noteworthy that the specific electrical resistance has increased by three or even four orders of magnitude.

Natural "smoked" 100 tires

Zinc oxide 5

Stearic acid 4

Cumar MH 1-0,5 7.5 (rubber grits)

MBT (Accelerator) 1

Sulfur 3

Huber Hi-Sil 233 45 (GILUDRAL - Federal Republic of Germany, A1 ₂ O ₃ 3H ₂ O)

Untreated "retour powder" (Example 3 starting material)

Retour powder treated according to Example 7

100

7.5

100 100

5

4

7.5 6

0.5

2.5 2.0

Example 8

composition I II. III. ARC. Neoprene WM-1 (rubber) 100.0 100.0 100.0 100.0 Zinc Oxide 5.0 5.0 5.0 5.0 Magnesium oxide 4.5 4.5 4.5 4.5 Paraffin 4.35 3.6 2.0 2.0 triethanolamine 1.0 1.0 - - Thiuram TMDT (Accelerator) 0.25 0.25 Vulcanox KSM (vulcanizing) 1.0 1.0 2.0 2.0 Vulcanit MBTS (vulcanizer) 1.0 1.0 0.5 0.5 Rodamine S-62 (dispersant) 1.0 1.0 1.5 1.5 Petrolatum (softener) 2.15 2.15 - - A1 ₂ O ₃ -3H ₂ O (Alumina trihydrate) 40.0 Precipitated Silicate (Filler) 32.0 32.0 32.0 32.0 untreated "Retour powder" (Example 1 starting material) 40.0 Retour powder treated according to Example 2 33.0 Retour powder treated according to Example 3 - - - 33.0

I = Comparative Reference Material (GILUDRAL - product of Guilini of Ludwighafen;

II = untreated "retour powder";

III = surface treated "retour powder";

IV = surface treated "retour powder".

The test results obtained are shown in Table VII. The following table summarizes:

VII. Spreadsheet

Test results I . Π · III. ARC. total weight (weight fraction) 192.25 191.5 180.5 180.5 Specific gravity (g / cm ³ ) 1.52 1.54 1.56 1.53 Vulcanization 200 C Vulcanization (time / minute) 2.0 2.0 1.5 1.5 Tensile strength (kg / cm ² ) 106.0 125.5 144.8 141.8 Tensile strength (mPa) 10.4 12.3 14.2 13.9 Strain% 875 733 688 700 Hardness Shore A 59 67 73 69 Defo flexibility 350/4 380/6 1100/11 900/10 Oxygen index% (above 30% "Flame retardant" product) 40.0 38.2 37.1 37.6

Comparative Reference Materials I and II;

III = untreated "retour powder";

IV = surface treated "retour powder".

The test results obtained are shown in Table VIII. It is summarized in a table.

VIII. Spreadsheet

Test results I II. III. ARC. Vulcanization! temperature 145 ° C Cure time (minutes) 20 15 15 12 Tensile strength (kg / cm ² ) 230 234 240.5 268.5 Elongation% Shore Hardness 600 520 560 670 54 55 55 56

Example 10

9.5 kg of "retour powder" (starting material of Example 5) in the apparatus of Example 5 were surface treated with the following composition:

component Quantity, kg Extraction oil 0.10 stearic 0.15 N-phenyl-N'-isopropyl-p-phenylene diamine 0.03 spindle Oil 0.13 Aldol-a-naphthylamine 0.05 1-mercapto-benzimidazole 0.03 naphthenic 0.01 0.50 kg II. example OSS: : ehasonlító components I II. * III. ** Sulfur (% by weight) 85% 80%, 100%, Extraction oil (% by weight) 4% 20 ° - ^v O Example 2 coated "Retour powder" n% - Total weight: 100% 100%, 100%,

* OT / 20A Surface Treated Sulfur (Katichemie) 65 ** Untreated Sulfur Powder.

-5. 187,695

Test results

Sulfur was tested in a mixture of natural rubber after vulcanization, where various benefits are characterized by an improvement in the physical constants of the test substance.

Composition of test substance:

Natural rubber

Zinc Oxide

Stearin

CBS Accelerator

Sulfur (for 100% active ingredient)

100 parts by weight 5 parts by weight 2 parts by weight

0.5 parts by weight 2.5 parts by weight

IX. Spreadsheet

Test results: I II. III. Ash content% 0.12 0.10 0.20 Acidity% 0.12 0.15 0.18 Specific gravity g / cm ³ 1.12 1.11 1.04 Vulcanization (160 ° C) 15 minutes 15 minutes 15 minutes Tensile strength mPa (Removed after 3 minutes of volc sample) 24.3 23.7 23.5 Tensile strength in the final product 24.1 23.1 22.7 Average standard deviation 0.6 0.8 1.05 300% modulus mPa 15.9 14.4 15.1 Hardness Shore Á 66 62 65

Patent claims

Claims (3)

1. A process for the preparation of aluminum oxide based white filler material _5, characterized in that the alumina manufacturing Bayerféle the calcining furnace formed from 1 to 33% by weight loss on ignition, 110 to 145 molecular weight, 2.5 to 3.0 g / cm ³ density, A "retour powder" having an aluminum content of 36-50% by weight and a hardness of 4.5-6.5 µg according to the Mohs scale, based on the weight of 0.1-8.0% by weight of a solid or liquid agent, preferably naphthenic acid, triethanolamine, stearic acid, extraction oil, spindle oil, organic silanol or silane, diethylene glycol, calcium stearate, dioctylphthalate, N-phenyl-N'-isopropyl-p-phenylene diamine, aldol-α-naphthylamine, or a mixture thereof, and then, if desired, the resulting product 20 _{0 with} known additives, preferably zinc oxide, accelerator and / or anti-aging agent. 2. The method of claim 1, wherein said retour _2g powder has an annealing loss of from 6 to 16% by weight. 3. The process according to claim 1 or 2, wherein the surface treatment comprises an agent containing from 0.1 to 1.0 parts by weight of a mixture of naphthenic acid and triethanolamine. 20 4. Figures 1-3. A process according to any one of claims 1 to 3, wherein the surface treatment comprises using a mixture of stearic acid, extraction oil or spindle oil, organic silanol or a mixture of silane, naphthenic acid and triethanolamine. Without illustration