A way of separating oil-filled styrene-(-methyl)- styrene rubber

 

(57) Abstract:

Use: manufacture of oil-filled styrene-(a-methyl)-styrene rubber. The inventive when receiving oil-filled styrene-(a-methyl)-styrene rubber at the stage of selection exercised by mixing an aqueous solution of coagulant with oil to obtain an oil emulsion. As an aqueous solution of coagulant use 1 - 50 % solution of polydimethyldiallylammonium taken as the dry substance in the amount of 1.5 - 2.0 kg/ton of rubber. Then implement the mixture of rubber latex with oil emulsion was acidified serum and mineral acid. table 2.

The invention relates to the production of oil-filled styrene-(-methyl)-styrene rubbers obtained by the emulsion copolymerization of butadiene with styrene or a-methylstyrene and filled with mineral oils, in particular to methods of making them from latex, and can be used in the petrochemical industry.

Known way to select the best choice and butadiene-a-methylstyrene rubber from latex using as coagulating agents substances protein origin [1]

Main is not the rubbers are the uneven distribution of oil in the rubber, which has a significant influence on the properties of rubber, so as together with the oil in the rubber is injected and a stabilizer (antioxidant). Non-uniform distribution in the polymer creates preconditions to the loss of a number of properties of the resulting rubber. This is because the rubber dehydrating and drying is subjected to thermo-mechanical stress. In addition, for complete coagulation requires low pH values and correspondingly high consumption of sulphuric acid on acidification.

Closest to the claimed technical solution is a way of separating oil-filled rubber from latex, which consists in coagulation of the latex aqueous solution of sodium chloride and a mineral acid, including recycling of serum, the concentration of crumb rubber, washing it with water, followed by extraction and drying [2] the Use of a solution of sodium chloride for coagulation oil-filled rubbers though and provides a good distribution of oil in the rubber, however, has several disadvantages.

The main disadvantages of this method of allocating oil-filled rubbers are high consumption coagulating agent is sodium chloride (200 - 250 kg/ton of rubber), pollution industrial wastewater chloride naet and expensive process. In addition, separation of rubber from latex using sodium chloride is very sensitive to pH and can be effective only in acidic media at pH 3 to 4.

The challenge which seeks the invention is to simplify the technology and the improvement of the properties of oil-filled styrene-(a-methyl)-styrene rubber.

For this task, there is a method of allocating oil-filled styrene-(a-methyl)-styrene rubber, comprising a mixture of rubber latex with oil, coagulation of the mixture by the introduction of a latex of an aqueous solution of coagulant, serum was acidified with sulfuric acid, and mineral acids emitting derived crumb rubber, initially provide an introduction to oil 1 50 aqueous solution of polydimethyldiallylammonium, which is the coagulant used in amounts of 1.5 to 2.0 kg/ton of rubber, with subsequent mixing of the latex with the obtained oil emulsion.

The use of the proposed method of allocating oil-filled styrene-(a-methyl)-styrene rubber from latex allows to simplify the extraction technology, to significantly reduce the amount of used and discharged industrial water and to improve the properties developed">

Below are some examples for allocation of oil-filled styrene-(a-methyl)-styrene rubber from latex.

Examples.

The first stage was carried out by the emulsion preparation of polydimethyldiallylammonium in mineral oil. To this end 1 50 aqueous solution of polydimethyldiallylammonium at a temperature of 70 90 C was mixed with the mineral oil used in the production of oil-filled rubbers containing antioxidant (naphthas-2, VS-1 or DFFD). For a homogeneous system was carried out by intensive stirring for 1 h Mass fraction of mineral oil (MO-6K) depending on the brand of the obtained oil-filled rubber was 14 of 17 for rubber SKS-30 apkm-15 or SKMS-30 (GOST 11138-78) and 26 to 29 for rubber SKS-30 apkm-27 or SKMS-30 apkm-27 (GOST 15628-79). Given that the value entered in the rubber mineral oil is a fixed value and is determined by the requirements of GOST for each grade rubber in the preparation of suspensions of polydimethyldiallylammonium in oil was carried out by changing the concentration and dosage on the rubber polydimethyldiallylammonium.

Butadiene-(o-methyl)-styrene latexes are served at first as a Pro is lilomanilla and stabilizer. The resulting mixture is fed to a coagulation in the unit with mixer where it is mixed with the acidified serum. For acidification is used 4,0 aqueous solution of sulfuric acid. the pH in the apparatus 5 6. Then the mixture is sent to the second apparatus with stirrer, where is acidified to 4.0 with an aqueous solution of sulfuric acid to a pH of 3.5 to 4.5. From doserates received crumb rubber, filled with oil, is directed to the removal of water and moisture during pressing and drying. The consumption of sulfuric acid is 12 to 16 kg/ton of rubber, the ratio of the latex serum 1 (2 3). The temperature of the coagulation 55 60aC.

Completeness of coagulation was determined visually. Serum transparent coagulation full.

The influence of the content of polydimethyldiallylammonium in mineral oil on the degree of coagulation of the latex and the properties of the obtained oil-filled styrene-(o-methyl)-styrene rubbers are shown in table. 1, 2.

Crumb obtained rubber medium-grained, friable, color uniform brown, with a small amount of white inclusions. When small doses of polydimethyldiallylammonium (less than 1.5 kg/ton of rubber) is not achieved full coagulation, and at high dosages (more than 2.5 kg/ton of rubber) observed the formation of small crumbs chocolatememichelle chloride in aqueous solution has no significant effect on the coagulation process. However, when applying a dilute aqueous solutions (less than 4.0) polydimethyldiallylammonium does not provide stability of the resulting system (observed stratification during standing) and therefore when stored requires constant stirring. More concentrated solutions of polydimethyldiallylammonium give a more stable system.

Properties of the obtained oil-filled rubbers are shown in table. 2.

From the above table. 2 data shows that oil-filled rubber isolated from the latex by the proposed method have a higher strength, resistance to aging. In addition, obtained according to the invention, the crumb rubber is more porous, friable, which positively affects the process of drying rubber is accelerated in comparison with the prototype for 15 to 20).

An important factor in the implementation of this allocation method on an industrial scale is no need to purchase additional expensive hardware. The implementation of this process on an industrial scale is carried out on the existing production equipment.

The method of selection of melanephelinites the introduction of an aqueous solution of coagulant, acidified serum, mineral acids emitting derived crumb rubber, characterized in that an aqueous solution of coagulant use 1 50% solution of polydimethyldiallylammonium, taken in an amount calculated on dry substance of 1.5 to 2.0 kg/ton of rubber, and the method is carried out in the following order: aqueous solution of coagulant is injected into the oil receiving oil emulsion with further mixing rubber latex with an oil emulsion, the introduction of acidified serum and mineral acids.

 

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FIELD: rubber industry.

SUBSTANCE: method consists in coagulation of latex with sodium chloride and mineral acid and is characterized by that mineral acid utilized is fiber-acidifying composite obtained by treating fibrous material for 10-60 min with sulfuric acid at 40-80°C, amount of the acid constituting 0.1 to 1.0% on the weight of rubber.

EFFECT: stabilized recovery process, reduced loss of rubber with produced rubber crumb, and weakened environmental pollution with rubber products.

4 tbl, 9 ex

FIELD: rubber industry.

SUBSTANCE: invention discloses a method for recovering synthetic rubbers from latexes stabilized by carboxylic acid soaps, which consists in action of mineral acid and organic amine coagulant on antioxidant-containing rubber latex. Organic amine coagulant is added in amount 0.01 to 1.0% in two steps: first portion constituting 50-90% of total amount of coagulant is added directly to latex and resulting mixture is stirred for at least 0.5 h at 20-70°C, after which second portion of coagulant or its mixture with mineral salt (coagulant/salt weight ratio from 1:0 to 1:15000) is fed into coagulation apparatus jointly with recycling serum at latex-to-serum weight ratio between 1:1 and 1:2. Rubber is thus obtained in the form of homogeneous porous crumb.

EFFECT: improved environmental characteristics of process due to lowered content of carboxylic acid soaps in waste water, which is also prevented to be polluted with leukanol, and accelerated drying of rubber crumb.

2 tbl, 18 ex

FIELD: fluid medium purification, production of emulsified synthetic rubber.

SUBSTANCE: coagulant based on protein component contains as additional ingredients carboxymethyl cellulose, carbamide, α- and β-amylase, fat aminoderivatives, carbamideformaldehyde resin and formalin in the next ratio (mass %): protein component 45.0-46.0; carboxymethyl cellulose 16.0-17.0; carbamide 10.1-10.2; α-amylase 9.4-0.5; β-amylase 9.4-9.5; fat aminoderivatives 8.8-8.9; carbamideformaldehyde resin 0.03-0.04; and formalin 0.02-0.03. 50 % of aminoderivatives may be replaced with alkylbenzyldimethylammonium chlorides. As protein component preferably animal- or plant-origin protein is used. Coagulant is used in 3-8 % aqueous solution form, and consumption thereof in process of fluid medium purification is 0.1-1.0 mass % based on mass of isolating rubber.

EFFECT: stabilized coagulation process; reagent of increased coagulating action; isolated rubber of improved quality.

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