The method of obtaining emulsion powdered rubbers

 

(57) Abstract:

The invention relates to the production of emulsion rubbers in powdered form and can be used in the synthetic rubber industry. Obtaining emulsion powdered rubbers include coagulation of the latex compounds of alkaline earth metals in the presence of antiagglomerants and antioxidants and possibly fillers with the subsequent removal of moisture. As a latex, a mixture of latex carboxylated elastomer and latex decarboxylative elastomer when a weight ratio of 80:20 to 20:80. The method allows to obtain emulsion powdered rubbers, which are good for storage, well-pressed, especially at elevated temperatures. 1 C.p. f-crystals, 1 table.

The invention relates to the production of emulsion rubbers in powdered form and can be used in the synthetic rubber industry.

A method of obtaining a diene rubber in powder form by treatment with aqueous dispersions of crumb rubber gidrofobizirovannym silica gel, followed by drying the obtained powdery product. Additionally within 5-15 min Khujand is likages use trimethylchlorosilane [USSR author's certificate 1808828 from 27.06.91, B. I. 14, 1993].

The main disadvantage of this method is the presence of powdered rubber additional substances that can have a negative effect on the properties of composite materials based on the rubber, in particular, due to the fact that trimethylchlorosilane can either hydrolyzed with the release of hydrogen chloride (hydrochloric acid).

Closest to the claimed is a method of obtaining a powdery rubber latex by adding acid or dispersion of carbon black, which has a pH in the range of 1-6 [U.S. Patent 4065426, op. 27.12.77]. Next, the resulting powder is mixed with latex and a water dispersion of carbon black. The mixture is coagulated, separated from the serum and dried.

The disadvantage of this method is the use of acid and water dispersion of carbon black with a pH of 1-6, which involves the use of expensive corrosion-resistant equipment and limits the scope of application of the powdered rubber.

The present invention is to simplify the technology and the expansion of applications of powdered rubber (by eliminating soot).

This result is achieved by a method of obtaining emulsion powder and antioxidants with the subsequent removal of moisture, whereby as a latex, a mixture of latex carboxylated elastomer (carboxylated latex and latex decarboxylative elastomer (decarboxylates latex) in a weight ratio of from 80:20 to 20:80.

Preferably the coagulation of the latex is carried out in the presence of fillers, the amount of which is kept in a range from 3 to 10% of dry matter.

The latex mixture is served on coagulation in a predetermined ratio. As decarboxylated latexes can be used the best choice (methylstyrene) latex type SCS-ARC, SCMS-10, SCMS-50, on BNR latex SKN-30MS, bn-40, SKN-26, polybutadiene latex ACS, latexes other elastomers that do not contain carboxyl groups. As the carboxyl-containing latexes can be used on BNR carboxylated latexes bn-30K-2, BOC-302, BOC-30/3, SKN-GP, the best choice carboxylate, BS-30K-3, carboxylated polybutadiene SKD-1, BK-5, etc. with content related methacrylic acid, from 1 to 5%.

Coagulation is performed with compounds of alkaline earth metals in the presence of antiagglomerants and antioxidants and possibly fillers. As fillers can be calcium stearate and zinc stearate.

As an antioxidant use darkening or neotemnaya antioxidants, amine-type: naphthas-2, g-130; phenol: Agidol-2 or phosphate: tennispalatsi etc.

In the process formed a small baby (less than 1 mm), which is easily separated from water, undergoes additional centrifuge for dewatering up to 30-40% or moisture is wrung out of the crumbs on the worm drive to its content of 3.5-4%, then the resulting granules rubber size 4x6 mm or crushed dried in the dryer and then easily grinded at room temperature crushers cutting or impact to the size of not more than 1,25 mm Such powdery rubber is stored without clumping.

Coagulation of the latex is carried out at a temperature of from 3 to 90oC. the Optimum temperature of coagulation is 205oC.

The crushing of rubber additionally antiglomerular not served.

The method is illustrated by the following examples.

Example 1

In a glass beaker 500 ml fill in 100 ml of latex bn-30K-2 with rigidity by Defoe 1400 GS with a dry matter content of 38% or 38 g and 39.6 ml latex SCS-ARC with rigidity by Defoe 2000 GS with a dry matter content of 24% or 9.5 g that decarbonate calcium (to 3.0% by weight of the polymer) and 1 g of calcium stearate. After stirring to the mixture also 1,43 g of calcium hydroxide as a 5% aqueous suspension in the water. The resulting mixture was stirred for 20 minutes When this happens coagulation of the latex with the formation of small crumbs of polymer. Crumb out moisture, ground in the mill coffee type and is dried to a moisture content of 1%. The resulting powder has a particle size of 1-1,25 mm and not stick together during storage. The properties of the polymer are shown in table.

Example 2

In a glass beaker 500 ml fill in 100 ml of latex SKN-30MS with rigidity by Defoe 1200 GS with a dry matter content of 38.4%, or 38,4, Then it poured for 54.4 ml latex bn-30K-2 with rigidity by Defoe 1400 GS with a dry matter content of 38% or 20,67 g, which corresponds to the ratio of polymer by weight of 65:35. The mixture is stirred, add to it (0,59 g Naftna-2 (1% by weight of the polymer), of 3.45 g of calcium carbonate (5,8% by weight of the polymer) and 1.38 g of calcium stearate. After stirring the mixture was added 5% aqueous suspension of calcium hydroxide containing 2.1 g of calcium hydroxide, and stirred the mixture for 20-25 minutes. The mixture of the latex coagulates into a fine crumb. After clarification of waste water, the polymer is separated from the water by extraction under pressure of inice. The obtained powder with a size up to 1.25 mm does not stick together during storage. The properties of the polymer are shown in table.

Example 3

In the apparatus with a capacity of 400 l pour 140 liters of water, add 1.6 kg of calcium hydroxide, the mixture is stirred for 15 minutes. In a separate container mix 58 l latex SCS-ARC with rigidity by Defoe 2000 Gauss and 30 l of latex bn-30K-2 with rigidity by Defoe 1400 Gauss or 11.3 kg 11.3 kg each, which makes them the weight ratio 50:50. The resulting mixture is slowly poured into the apparatus with an aqueous suspension of calcium hydroxide. At the same time add in a mixture of antioxidant Agidol-2 number 226, After coagulation of the latex (lightening serum) in the device add 0.45 kg of calcium stearate and continue stirring for another 10 minutes Later a small crumb rubber is fed to the vibrating screen, where the polymer is separated from the water, after which the crumb rubber is routed to the worm-press release, which pushes against moisture to its content in the polymer of 3.5-4% and granulated into granules of 4x6 see the resulting granules are transferred to a dryer of the type "John Dalglish" where are dried to a moisture content of 1.5% and then crushed by crushing machine until the particle size of 1-1,2 mm Obtained powdery rubber does not stick together during storage. Properties of rubber drink Defoe 1400 GS with a dry matter content of 38% or 38, To him poured 48.7 per ml of latex SCS-ARC with rigidity by Defoe 1200 GS with a dry matter content of 19.5%, or 9.5 g, which corresponds to a ratio of 80:20. The mixture is stirred for 5 min, then added to the mixture antioxidant Agidol-2 in the amount of 0.47 g, and continue stirring for another 5 minutes then, to the obtained mixture is added aqueous 5% suspension of calcium hydroxide containing 2,37 g hydroxide, and continue stirring until the lightening mixture. Then, to the suspension of coagulum add to 0.47 g of calcium stearate and mix for another 5 minutes the resulting mixture is separated from the water by the method of spin, grind in a coffee mill and dried in a dryer to a moisture content of not more than 1.5%. The resulting powder does not stick together during storage. Properties of rubber are shown in table.

Example 5

In a glass beaker 500 ml poured 100 ml of latex SKN-30MS with rigidity by Defoe 1200 GS with a dry matter content of 38.4%, or 38,4, Then it poured 68,9 ml carboxylated latex SKD-1C with rigidity by Defoe 2000 GS with a dry matter content of 30% or 20,67 g, which is the ratio of the polymers 65:35 by weight. The mixture is stirred, add to it 0,59 g Agidol-2 (1% by weight of the polymer), 1.4 g of calcium stearate or 2,37% by weight of the polymer and gobena 20 minutes Coagulation takes place a mixture of latexes in a fine crumb. After that, the chips are separated from the serum, wring out the excess moisture, grind in a coffee mill and dried at 60-70oWith in the dryer, stirring occasionally. After 30 minutes the crumb rubber particle size of up to 1.25 mm reaches a moisture content of 1.5%. Crumb is cooled to room temperature. The obtained powdery rubber does not stick together during storage. Properties of rubber are shown in table.

Example 6

In a glass beaker 500 ml poured 130 ml latex SCS-ARC with rigidity by Defoe 1200 GS with a dry matter content of 24% or 31.2 g of the polymer and then a 44.2 ml of latex is the best choice carboxylate BS-30K-3 with rigidity by Defoe 1400 GS with a dry matter content of 38% or 16.8 g, which is the ratio of the polymers 65:35 by weight. To a mixture of latex is added antioxidant Agidol-2 in the amount of 1% by weight of a mixture of polymers or of 0.48 g, antiglomerular calcium stearate 2% or 0.96, the Mixture was stirred. Then to the mixture is poured 28,8 ml of 5% calcium hydroxide or 1.44, the Mixture is stirred for at least 20 minutes to complete coagulation of the mixture of latex and education crumb polymer. The polymer is separated from the water, wring out the excess moisture, rasmol and residual moisture of 1.5%. The resulting rubber is cooled. The properties of the polymer are shown in table.

Example 7

In a glass beaker 500 ml poured 234 ml latex SKN-30MS with rigidity by Defoe 1200 GS with a dry matter content of 38.4%, or 90, Then it is poured 28,5 ml carboxylated latex SKD-1C with rigidity by Defoe 2000 GS with a dry matter content of 35.1%, or 10 g, which is the weight of 90:10. The mixture is stirred for 5 minutes Then add to the mixture anioxidant Agidol-2 in the amount of 0.8 g and continue stirring for another 5 minutes the resulting latex mixture is poured into aqueous suspension of calcium hydroxide and calcium carbonate. After coagulation of the latex (lightening serum) in the apparatus serves 1% of dry matter calcium stearate. Stirring is continued for another 5 minutes. The resulting mixture is separated from the water by the method of spin, grind in a coffee mill and dried in a dryer to a moisture content of not more than 1.5%. The obtained rubber-caking during storage. Properties of rubber are shown in table.

Example 8

In a glass beaker 500 ml poured 26 ml latex SKN-30MS with rigidity by Defoe 1200 GS with a dry matter content of 38.4%, or 10, Then it is poured's figure of € 256.4 ml carboxylated latex SKD-1C with the stiffness within 5 minutes Next, to this mixture antioxidant Agidol-2 in the amount of 0.8 g and continue stirring for another 5 minutes the resulting latex mixture is poured into aqueous suspension of calcium hydroxide and calcium carbonate. After coagulation of the latex (lightening serum) in the apparatus serves 1% of dry matter calcium stearate. Stirring is continued for another 5 minutes the resulting mixture is separated from the water by the method of spin, grind in a coffee mill and dried in a dryer to a moisture content of not more than 1.5%. The resulting powder does not cake during storage. Properties of rubber are shown in table.

Example 9

In a glass beaker 500 ml poured 52,1 ml latex SKN-30MS with rigidity by Defoe 1200 GS with a dry matter content of 38.4%, or 20, Then it is poured 228 ml carboxylated latex SKD-1C with rigidity by Defoe 2000 GS with a dry matter content of 35.1%, or 80 g, which corresponds to a ratio of 20:80. The mixture is stirred for 5 minutes Then added to the mixture antioxidant Agidol-2 in the amount of 0.8 g and continue stirring for another 5 minutes the resulting latex mixture is poured into aqueous suspension of magnesium hydroxide and calcium carbonate in an amount of 10% on the polymer). After coagulation of the latex (lightening serum) in the apparatus serves 3% on stima, grind in a coffee mill and dried in a dryer to a moisture content of not more than 1.5%. The resulting powder does not cake during storage. Properties of rubber are shown in table.

Example 10

In a glass beaker 500 ml fill in 100 ml of latex SKN-30-MS with rigidity by Defoe 1200 GS with a dry matter content of 38.4%, or 38,4, Then it poured a 20.2 ml latex bn-30K-2 with rigidity by Defoe 1400 GS with a dry matter content of 38% or of 7.68 g, which corresponds to the ratio of polymer to 80:20. The mixture is stirred. To the mixture is added a filler of 20% aqueous suspension of talc in the amount of 23 ml or 4.6 g, 0.4 g of antioxidant Agidol 2.1 g of calcium stearate or 2,17%, counting on the polymer. The mixture is stirred to achieve a homogeneous mixture. Then to the mixture is added 5% aqueous suspension of calcium hydroxide containing 2.76 g of a hydroxide and stir the mixture for 20 minutes, the latex Mixture is coagulated with the formation of small crumbs. After separation of the polymer from the water it press on the press from excess moisture to its content of 25-30%. The polymer is ground in the mill to a size of no more than 1.25 mm and dried under vacuum to 350 mm RT.article under stirring at a temperature of 60-80oWith to a moisture content of not more than 1.5%. The properties of aucune based latex carboxylated elastomer and latex decarboxylative elastomer when a weight ratio of from 80:20 to 20:80 are good for storage, well-pressed, especially at elevated temperatures, have different Mooney viscosity, which allows you to expand the scope of their application.

1. The method of obtaining emulsion powdered rubbers by coagulation of the latex compounds of alkaline earth metals in the presence of antiagglomerants and antioxidants with the subsequent removal of moisture, characterized in that as a latex, a mixture of latex carboxylated elastomer and latex decarboxylative elastomer when a weight ratio of 80: 20 to 20: 80.

2. The method according to p. 1, characterized in that the coagulation of the latex is carried out in the presence of fillers, the amount of which is kept in the range of 3 - 10% dry matter.

 

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4 tbl, 9 ex

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3 tbl, 11 ex

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2 tbl, 11 ex

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