A method of obtaining a polystyrene latex

 

(57) Abstract:

Usage : the invention relates to technology of polymers, in particular to methods for polystyrene latex, and can be used in the production of those for various applications,for example in the production of foam, water-based paints, coated paper. The essence of the invention : a method of obtaining a concentrated nizkoemissionnoi polystyrene latex with a particle size of the copolymer 180 - 240 nm by emulsion polymerization of styrene with the introduction of the emulsifier and monomer in the process. The total amount of emulsifier is 0.5 to 1.5 wt.h., in the beginning of the process and impose 0.1 - 0.3 wt.h. emulsifier and 94 - 97 wt.h. monomer is injected during the process with speed, ensuring that the system mass ratio of styrene : polystyrene in the range of 1 :(1.5 to 8.0 in). table 1.

The invention relates to technology of polymers, in particular to methods for polystyrene latex, and can be used in the production of those for various applications (production of foam, water-based paints, coated paper, etc.)

A method of obtaining polystyrene is to, this method does not allow to obtain a concentrated latex, sustainable in the synthesis process.

A method of obtaining polystyrene latex by emulsion polymerization of styrene with the introduction of the emulsifier and monomer during the process with speed, providing the conversion of previously entered monomer and 90 to 98% that is enabled in the system, the ratio of styrene polystyrene within(1 9)-(1 49). In the beginning of the process in the apparatus injected 0.2 wt.h emulsifier (to 0.15 wt. on the water) and 10 wt. h styrene [2] the Method allows to obtain a stable as in the synthesis process, and subsequent mechanical stress latexes with a concentration 43 46% the Disadvantage of this method is to obtain a latex of relatively small particle size (110 to 150 nm). The disadvantages of this method should also include the need to introduce large quantities of emulsifier from 3.6 hours to 5.0 wt. h, which in turn leads to significant foaming ability of the latex. High spumescence latex reduces its technological properties in the manufacture of paints, coated paper and forced to enter a special panagsama supplements.

The present invention is to obtain concentrated the SPE particles reduces their specific surface area and as a result of their adsorption unsaturation, to reduce the amount of added surfactant stabilizer (emulsifier) without loss of stability of the latex.

The problem is solved using the developed method for concentrated polystyrene latex, which consists in initially forming a reduced front growth of latex particles with subsequent controlled polymerization impose 0.1-0.3 wt.h. emulsifier and 3 to 6 wt. including the monomer. The remaining amount of the monomer and emulsifier injected during the process continuously or in portions with speed, ensuring that the system ratio of styrene polystyrene within 1 (1,5 8,0).

The invention is illustrated by the following examples.

Example 1 (the prototype).

Charged to the reactor 105 g (105 wt.h.) water, 0.2 g ( 0.2 wt. including potassium oleate), 0.15 g (0,15 wt. h) of potassium persulfate, 0.1 g (0.1 wt. h) hydrate potassium oxide, 0.05 g)of 0.05 wt. h) trylon B. Raise the temperature of the reaction mass up to 70oC and enter 10 g (10 wt.h.) styrene. Upon reaching concentrations of latex of 8.2% (98% conversion) in the reactor is injected 6.7 g of 15% aqueous solution of potassium oleate (1 wt.h. emulsifier and 5.7 wt.h. water) and 40 g (40 wt.h.)styrene. When reaching a concentration of latex 28% (9 is) and 50 g (50 wt.h.) styrene. Polymerization continues until the exhaustion of styrene. The total curing time is 10 o'clock the Final latex has a concentration of dry matter 43 srednesemennyh the size of the latex particles of 120 nm. The total content introduced during polymerization emulsifier is 3.6 g (3.6 wt.h.).

Example 2.

Charged to the reactor 115 g (115 wt.h.) water, 0.15 g (0,15 wt.h.) lauryl sodium, 0,6 (0,6 wt.h.) the trylon B. Raise the temperature to 60oC and enter 5 g (5 wt.h.) styrene. After one hour begin continuous introduction into the reaction mass 95 g (95 wt.h.) styrene and 5,67 g of 15% aqueous solution of sodium lauryl ( 0.85 wt.h. lauryl sodium and 4,82 wt.h. of water). Supply of reagents carried out with a speed that supports the system the ratio of styrene polystyrene equal to 1 to 1.5. At the end of the feed temperature was raised to 70oC and continuing the polymerization until the exhaustion of styrene. The total polymerization time is 8 o'clock the Final latex has a concentration of 44.1% of the particle size of 226 nm, the content introduced in the polymerization of lauryl sodium is 1.0 g (1.0 wt.h.).

The invention is illustrated by examples 2 to 5.

As anion active emulsifier may also espolitikae parameters of the method are given in the table.

Properties of the obtained latex is presented in the table.

Analysis of the data presented in the table suggests that the introduction of the proposed method in the beginning of the process of 0.1 to 0.3 wt. hours of emulsifier and 3.0 to 6.0 wt. including styrene, followed by the introduction of the rest of emulsifier and monomer with a speed that supports the system, the ratio of styrene polystyrene within 1 (1,5 8,0) allows to obtain a stable nizkotemperaturnye latexes of high concentration.

A method of obtaining a polystyrene latex by emulsion polymerization of styrene with the introduction of the emulsifier and monomer in the process, characterized in that the total amount of emulsifier for polymerization is 0.5 to 1.5 wt.h. in the beginning of the process and impose 0.1 to 0.3 wt.h. emulsifier and 3 to 6 wt.h. monomer, and the remaining amount of emulsifier and 94 97 wt. including the monomer is injected during the process with speed, ensuring maintenance of the system mass ratio of the styrene polystyrene 1 1,5 8,0 respectively.

 

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