CS202782B1 - Vinyl chloride polymerisation and/or copolymerisation method - Google Patents

Description

(54) a method of polymerizing and / or copolymerizing vinyl chloride. \

It is an object of the present invention to provide a process for the polymerization and / or copolymerization of vinyl chloride, wherein the conditions are selected such that they substantially affect the formation of increments on the walls of the polymerization apparatus without affecting the economy of production.

During the present production of polyvinyl chloride, deposits of polyvinyl chloride were formed on the reactor walls. The deposits cause a reduction in yield, impairing heat transfer, which in the end results in a difficult temperature control regime. In addition, the resulting deposits also reach the product, thereby deteriorating its quality. After several polymerization cycles, the reactor needs to be opened and mechanically stripped. This operation is time-consuming and production downtime is reduced.

There are currently several methods known for avoiding the formation of deposits. Oe it for. In particular, the protection of the reactor walls by spraying with low pressure water, the choice of more suitable construction materials, isothermal conduction of the polyreaction with a focus on the wall and polymerization batch temperature, painting the walls with organic compounds, organic dyes, inorganic pigments, polymeric substances and other substances capable of inhibiting polymerization reactor walls.

Generally, the advantage of alkaline polymerization is reported. Sodium bicarbonate, alkali metal hydroxides, alkali metal hydroxides are used for this purpose

202 782

202 782, or the corresponding oxides are applied directly. Additions of oxidizing agents are also known in addition to other systems to provide a comprehensive impact on the ongoing process. Oe to eg. an additive of manganate, manganese acid, chromic acid, dichromic acid or a salt thereof, calcium hypochlorite. Nitric acid, nitrous oxide, nitric oxide, copper nitrate, lead nitrate, silver nitrate, and the like can also be used. All these measures are ineffective, respectively. their use is not suitable for high toxicity and corrosion of equipment materials.

These and other drawbacks of the prior art are overcome by the present invention.

According to the present invention, a process for the polymerization and / or copolymerization of vinyl chloride by 8 other vinyl monomers, at least 8 aliphatic monomers, in the presence of polymerization initiators and other auxiliaries and a surfactant at a temperature of 20 to 80 ° C is carried out. / or hydrazine and / or its alkyl-substituted derivatives, β preferably monoalkilohydrazines, dialkylhydrazines, trialkylhydrazines, wherein the alkyl contains 1 to 10 carbon atoms, and preferably 1 to 4 carbon atoms, optionally containing an aubetltuant selected from the group comprising amino and / or hydroxyl, and / or their inorganic and / or organic acid salts in an amount of 2.5-10 ^-3 to 1.10 ^-1 % by weight, calculated on the amount of water used.

Hydrazine and / or derivatives thereof may be coated on the reactor walls and / or added to the aqueous phase in the natural form or as 5-65 wt. solutions, and preferably 15-50 wt.%, solutions in water, optionally other solvents, and preferably cyanal polar solvents and 1 to 6 carbon atoms during polymerization and / or prior to polymerization, and preferably simultaneously and monomer.

The modification of the polymerization or copolymerization by the process according to the invention does not in any way affect the use of other components in polymerization institutes. For example, commonly used initiation systems, either individually or mixed, as organic peroxides, initiated ready initiators, inorganic peroxides, and can be used in conventional quantities and any type of choice as well as emulsifying or permeable agents, molecular weight regulators, pH adjusters , solvents and other excipients.

It follows that the spdaob of the present invention does not require any alteration of the tachnological process and does not substantially affect the device and is therefore applicable to conventional equipment.

Among the advantages of the process according to the invention are, in particular, the fact that the application of minimal amounts of technically available substances can very positively influence the formation of increments on the polymerization apparatus, thereby greatly increasing the utilization of this apparatus and thereby its production. cleaning the polymerization apparatus and preventing mechanical damage caused by such cleaning agents. In addition to increasing production due to better utilization of the equipment and from the shifting of strenuous washing, predisposition and product contamination, waste water pollution and environmental corrosion will be reduced. All these factors have a further impact on the reduction of the so-called. in the final polymer as well as to display the formation of high polymerization species.

The process according to the invention is illustrated in the following examples.

Example 1

-2 3

In a 1.10 m stainless steel polymerization reactor, suspension polymerization of vinyl kiori is carried out. ÁuUkUv ia RiplRi i, i kg deetilovinij water óbóhújífifij

2.Ϊ0 ' ⁴ kg of methylhydrazine to which 4.10 ^-3 kg of Ca (OH) ₂ , 8.10 ^-3 kg of diisopropyl peroxydicarbonate (IPP) and 3.5.10 ^-3 m ^{3 of} vinyl chloride are added. The reaction takes place at 56 ° C and a stirrer speed of 2.5 EREV ^-1. After 6 hours 85% conversion was achieved. After 50 batches of -3-2, there is a deposit of about 2.10 kg m on the wall of the reactor as well as on the stirrer, which can be removed with a stream of water. At the beginning of the polymerization the pH is 1.5, at the end of the reaction the pH is greater than 8.

Example 2 * • 2 3

In a polymerization reactor with a volume of 1.10 m e, the copolymerization of vinyl chloride and vinyl acetate (VAC) is performed. The autoclave is charged with 4.8 kg of distilled water containing 10.4 ^"4 kg 2 - hydroxyethyl hydrazine, which was added to 2,9.10 ^-3 m ³ of vinyl chloride, 5,2, ⁴ m ΐδ ³ VAC, 10.8 kg of PPI ^{-3, -3} 4:10 kg Ca (OH) ₂ . The deposit on the reactor forms a coating visible up to —3–2 batches in an amount of about 2.10 kg m

Example 3 —2 3

In a 1.10 m stainless steel polymerization reactor, polymerization was carried out as in Example 1 except that 0.6 g of 1,1,2-trimethylhydrazine was used in place of methylhydrazine. The reactor coating is only visible after 45 batches in an amount of about 2.10 ^-3 kg m ^-2 .

Example 4 • «2 3

In a polymerization reactor of stainless steel the content of 1.10 m is to perform the polymerization as in Example 1 a except that methylhydrazine is used in place of 3.10 kg of 1,1 dimethylhydrazine ^-4. The reactor coating is visible after 55 batches in an amount of 2.10 ^-3 kg m ^-2 .

Example 5

-2 3

In a 1.10 m stainless steel polymerization reactor, carry out the polymerization as in Example 1, but without the addition of methylhydrazine. After 5 batches, the walls of the autoclave are clogged and prevent uniform heat transfer. The clogging of the inner surface of the 2 autoclave is about 0.2 kg m.

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Example 6

-2 3

In a 1.10 m stainless steel polymerization reactor, the polymerization was carried out as in Example 1b, except that 6.10 ^-3 kg of aqueous solution of hydrodesin hydrate was used instead of methylhydrazine e. Reactor Coating Visible after 35 batches

-3 —2 at 2.10 kg m.

Example 7 «• 2 3

In a 1.10 m stainless steel polymerization reactor, polymerization was carried out as in Example 1b, except that 5.10 kg of 2-aminoethylhydrazinium sulfate was used instead of methylhydrazine. The reactor coating is only visible after 55 batches in an amount of 2.10 ~ ³ kg m ² .

Example 8

e.2 3

In a stainless steel polymerization reactor with a circulation of 1.10 m, polymerization was carried out as in Example 1 by using 2.10 ³ kg instead of methylhydrazine e.

Of 10-hydroxydecylhydrazine in 6.10 ^-3 kg of monoethylene glycol diethyl ether. The reactor coating is detectable up to 30 batches in an amount of 2.10 kg m.

Example 9 • «2 3

In a 1.10 m stainless steel polymerization reactor, polymerization was carried out as in Example 1, except that 2-methyl- ³ -aminodecylhydrazinium acetate (2.10-3 kg) was used in 1.10 kg of a 60% solution in non-methyl methylhydrazine e. methanol in water. The coating of the -2 -2 reactor is visible even after 30 batches in an amount of 2.10 kg m.

Claims (1)

OBJECT OF THE INVENTION Process for polymerizing e / or copolymerizing vinyl chloride with other vinyl chloride. monomers, in particular aliphatic, in the presence of polymerization initiators of β longer surfactants at a temperature of 20 to 80 ° C, characterized in that hydrazine and / or its electrolysubstituted derivatives are applied to and / or added to the polymerization system ea on the reactor walls. , β preferably monoalkylhydrazines, dialkylhydrazines, trialkylhydrazines wherein the alkyl contains 1 to 10 carbon atoms, β preferably 1 to 4 carbon atoms optionally containing a substituent selected from the group consisting of amino and / or hydroxyl, e / or their inorganic and / or salts thereof % of organic acids in an amount of 2.5.10 " ³ to 1.10" ¹ % by weight, β preferably 5.10 " ³ to 5.10 * ² % by weight, calculated on the amount of water used.