FI61705C - FOERFARANDE FOER FRAMSTAELLNING AV POLYVINYLKLORID - Google Patents

Description

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Patents and Registration of Amm and Icl and Other Pub Publications 31.03.82 (32) (33) (31) Pyydetty ttuolkeii -Begird priority 26.02.76 USSR (5U) 2328148 (71) (72) Julia Alexandrovna Zvereva, Prospekt Pobedy, 2, sq. Km. 22, Dzerzhinsk Gorkovskoi oblast, Evgeny Pavlovich Shvarev, Prospekt Chkalova, 158, sq. Km. 1, Dzerzhinsk Gorkovskoi oblast, Mikhail Alexandrovich Karpachev, ulitsa Pirogava, 32, kv. 13, Dzerzhinsk Gorkovskoi oblast, Boris Grigorievich Moiseev, ulitsa Vatutina, 15 »kv. 62, Dzerzhinsk Gorkovskoi oblast, Valery Yakovlevich Kolesnikov, ulitsa Sverdlova, 84a, kv. 52, Dzerzhinsk Gorkovskoi oblast, Jury Pavlovich Fokin, ulitsa Pozharskogo, 8/34, kv. 5, Dzerzhinsk Gorkovskoi oblasti, USSR (SU) (74) Oy Kolster Ab (54) Method for the production of polyvinyl chloride - Förfarande för framställning av polyvinylklorid -aineeksi.

In a prior art method of preparing polyvinyl chloride, vinyl chloride is polymerized in suspension using percarbonate-type active initiators, which are synthesized directly during in situ polymerization in an autoclave reactor which is an autoclave (see U.S. Pat. No. 3,022,281). The initiator used in this process is diethyl peroxydicarbonate, which has the advantages of safety when working with the active polymerization initiator (staff are not directly in contact with the starting igniter) and high efficiency, since the initiator is isolated as a separate step. is not needed.

But the polymerization reaction proceeds more slowly in this process than if the same catalyst were used in the finished form.

2 6 ") 705 The polyvinyl chloride particles obtained by this method are not granular but cult. In addition, the polymer adheres to the inner walls of the polymerization reactor.

The method has been improved from this. It was found that the polymerization could be accelerated by the use of a ready-made initiator, e.g. lauroyl peroxide (DE 2 039 010 of the Federal Republic of Germany).

Subsequently, methods have been proposed in which diisopropyl peroxide carbonate (Bots' patent publication SE 315 404) or diethyl peroxide carbonate (United Kingdom patent publication GB 1 262 706) is synthesized "in eitu" and achieves the same rates of polymerization in vinyl chloride. thighs in the same concentrations. This was achieved by using chloroformate, hydrogen peroxide and an alkaline compound in an equimolar ratio at a pH of not more than 7.0 at the beginning of the polymerization process.

Another method was later proposed in which polyvinyl chloride was obtained in better quality, namely in the form of homogeneous granules (U.S. Pat. No. 3,799,916).

This was achieved by carrying out the polymerization and synthesis of the initiator in an acidic medium (pH below 7 → 0). However, in this process of polymerizing vinyl chloride, the polymer adhered to the inner walls of the reactor ("flaking").

Thus, all the improvements associated with those vinyl chloride polymerization processes. in which the initiator is synthesized "in situ" have been directed at increasing the rate of polymerization and improving the quality of the polyvinyl chloride, but it has not yet been possible to prevent the polymer from adhering to the inner walls of the reactor.

The object of the present invention is to reduce the adhesion of polyvinyl chloride to the reactor walls while maintaining a high polymerization rate and a high quality polymer.

More specifically, it is an object of the present invention to improve the suspension polymerization process used for the preparation of polyvinyl chloride, in which the polymerolytin thinner is synthesized "in situ" so as to reduce the adhesion of polyvinyl chloride during the polymerization process.

Said object is achieved by providing a suspension polymerization process using chloroformate, hydrogen peroxide and alkali for the preparation of polyvinyl chloride, and the process of the invention is characterized in that 2-ethylhexyl chloroformate, cyclohexyl chloroformate or 2-ethylformor the molar ratio is 2: 1: 3-20, and that the pH is not less than 10.

According to the invention, said chloroformate is used in an amount of 0.01 to 0.1 part by weight per 100 parts by weight of vinyl chloride.

Vinyl chloride polymerizes efficiently when the molar ratio of chloroformate, hydrogen peroxide to alkali is 2: 1: 3-3 and the pH is 10-12.

The proposed method virtually eliminates (90-100%) the formation of a polyvinyl chloride layer on the reactor wall during the polymerization process. The rate of polymerization is high, practically the same as when using a finished initiator such as ready-made 2-ethylhexyl peroxydicarbonate, cyclohexyl peroxydicarbonate or 2-butoxyethyl peroxydicarbonate.

The method proposed here is easy to implement. Water, emulsifier, alkali and hydrogen peroxide are charged to the polymerization reactor. A vacuum is drawn into the apparatus and then chloroformate and vinyl chloride are added. The polymerization temperature is 45-65 ° C · The initial igniter is efficiently synthesized while heating the reaction mixture to the desired reaction temperature in 0.3-1.0 hours.

Said result can be obtained only if said process details are strictly followed, i.e. if said chloroformates, hydrogen peroxide and alkali are used in a molar ratio of 2: 1: 3-20 and if the pH1 of the medium1 is not less than 10. If these requirements are not met, said result not achieved. This fact will become clear later from the following examples.

The invention is illustrated by means of examples. In Examples 1, 2, 3, 4, 3 and 6, polyvinyl chloride is prepared by the process of the invention, Example 7 illustrates a process for the preparation of polyvinyl chloride using a finished initiator, and Examples Θ, 9 and 10 for the preparation of polyvinyl chloride under non-compliant conditions.

Example 1

A reactor equipped with a stirrer and an automatic heat exchange system with a capacity of 193 liters is charged with 200 parts by weight of water, 0.06 parts by weight of emulator (Methooel 63 GH-50), 0.0163 parts by weight (3 moles) of NaOH, pH <10 , 6, and 0.0163 parts by weight (1 mole) of 28 36 hydrogen peroxide. A vacuum is drawn into the reactor and then 0.03 parts (2 moles) of 2-ethylhexyl chloroformate and 100 parts by weight of vinyl chloride are added. The reaction mixture is heated to 53 ° C in 40-30 minutes. The result is 4, 61,705, about 0.04 parts by weight of di-2-ethylhexyl peroxydicarbonate. The reaction is continued at this temperature for 6 l / 2 hours. The yield is 90 parts by weight of polymer. No polymer adheres to the reactor walls.

Example 2

The procedure of Example 1 is followed, but 0.042 parts by weight (2 moles) of cyclohexyl chloroformate are added. The reaction is continued for 5 hours 43 minutes. The yield of polyvinyl chloride is 90 parts by weight.

Example 3

The procedure of Example 1 is followed, but 0.047 parts by weight (2 moles) of 2-butoxyethyl chloroformate are used. The reaction is continued for 6 hours 40 minutes. The yield of polyvinyl chloride is 90 parts by weight.

Example 4

The procedure of Example 1 is followed, but using 0.0033 parts by weight (3 moles) of NaOH, pH 10.2, 0.0037 parts by weight (1 mole) of 2% hydrogen peroxide and 0.01 part by weight (2 moles) of 2 -etyyliheksyyliklooriformiaattia. The reaction is continued for 16 hours. The polymer yield is 90 parts by weight.

Example 3

The procedure of Example 1 is followed, but using 0.033 parts by weight (3 moles) of NaOH, pH 11.6, 0.037 parts by weight (1 mole) of 28% hydrogen peroxide and 0.1 part by weight (2 moles) of 2-ethylhexyl chloroformate. The reaction is continued for 3 hours. The polymer yield is 90 parts by weight.

Example 6

The procedure of Example 1 is followed, but 0.11 parts by weight (20 moles) of NaOH, pH 13.8, 0.0185 parts by weight (1 mole) of 28 hydrogen peroxide and 0.05 parts by weight (2 moles) of 2- etyyliheksyyliklooriformiaattia. The reaction is continued for 6 hours 35 minutes. The yield of polyvinyl chloride is 90 parts by weight.

In Examples 2, 3, 4, 5 and 6, polyvinyl chloride does not accumulate in the reactor walls.

Example 7

The reactor described in Example 1 is charged with 200 parts by weight of water, 0.06 parts by weight of emulsifier (Methocel-65 GH-50), the reactor is evacuated and then 0.04 parts by weight of finished di-2-ethylhexyl peroxydicarbonate and 100 parts by weight of parts by weight of vinyl chloride. The contents of the reactor are heated to 53 ° C * in 40-50 minutes. The polymerization reaction is continued at this temperature for 6 hours 25 minutes. The yield of polyvinyl chloride is 90 parts by weight. Polymer accumulates in the reactor walls.

Comparing Examples 1 and 7, it is found that the polymerization rate is practically the same when using di-2-ethylhexyl peroxydicarbonate synthesized "in situ" or prepared di-2-670705 ethylhexyl perokeidicarbonate at the same concentration.

Example Θ (comparison)

The procedure of Example 1 is followed, but using 0.011 parts by weight (2 moles) of NaOH, pH 9.0, 0.0185 parts by weight (1 mole) of 28 l of hydrogen peroxide and 0.05 part by weight (2 moles) of 2-ethylhexyl chloroformate. * The polymerization time is 10 hours. The polymerization temperature is 53 ° C * The polymer yield is less than 15 parts by weight.

Example 9 (comparison)

The procedure of Example 1 is followed, but 0.0165 parts by weight (3 moles) of NaOH, pH 10.6, 0.0185 parts by weight (1 mole) of 28 l of hydrogen peroxide and 0.034 parts by weight (2 moles) of isopropyl chloroformate are used. When the polymerization is continued for 10 hours, the polymer yield is 10 parts by weight.

Example 10 (comparison)

The procedure of Example 1 is followed, but using 0.0165 parts by weight (3 moles) of NaOH, pH 10.6, 0.0185 parts by weight (1 mole) of 28 hydrogen peroxide and 0.0233 parts by weight (2 moles) of ethyl chloroformate. . When the reaction is continued for 10 hours, the polymer yield is 12 parts by weight.

For the sake of clarity, Examples 8, 9 and 10 have been used to illustrate the situation which arises when deviating from the conditions defined in the invention.

In Example 8, the molar ratio of alkali, hydrogen peroxide to chloroformate is exceptional, but the required 2-ethylhexyl chloroformate has been used as the chloroformate. In this case, the polymerization rate is very low and the reaction is practically not completed.

In Examples 9 and 10, different chloroformates are used, but the ingredients are in their molar ratio according to the invention. Again, the polymerization is slow and the reaction is virtually incomplete.

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