BE863075A - VINYL MONOMERES POLYMERIZATION PROCESS - Google Patents

Description

       

  Monomer polymerization process

  
The present invention relates to a process for the polymerization of one or more vinyl monomers and, more particularly, to a new and improved process for the polymerization of one or more vinyl monomers, in the presence of a polymerization initiator, in a polymerization reactor.,

  
 <EMI ID = 1.1>

  
of unwanted polymer on the internal walls of the polymerization vessel and on other surfaces of parts or components of the polymerization reactor., for example

  
 <EMI ID = 2.1>

  
monomers, is greatly reduced.

  
 <EMI ID = 3.1>

  
knows several types of polymerization processes for the polymerization of one or more vinyl monomers, such as suspension polymerization, emulsion polymerization, solution polymerization and bundle polymerization, none of these processes being free of the problem posed by depositing polymer crusts or encrustations on the internal walls of the polymerization reactor and on the surfaces

  
 <EMI ID = 4.1>

  
stirrer.

  
The prior art processes suffer from various disadvantages due to the deposition of polymer crusts or encrustations on the internal walls of the polymerization reactor and on the surfaces of the agitator.

  
and the like coming into contact with the monomer (s), including loss of polymer yield, lowering

  
 <EMI ID = 5.1>

  
merization and undesirable quality of polymer products obtained by the fact that encrustations

  
or polymer crusts detach from the surfaces and possibly enter the products obtained. To these drawbacks, we must also add the length of time

  
and the much too much labor required to remove crusts or polymer encrustations from the surfaces after each polymerization cycle, as well as the health problem that faces workers in the

  
caused by inhalation of volatile monomers, such as vinyl chloride, a problem which was recently considered very serious.

  
A whole series of processes have already been proposed for the prevention of the deposit of encrustations or crusts.

  
of polymer on the internal walls of the polymerization reactor and on the surfaces of the stirrer and the like. For example, a method has already been described according to which

  
the internal walls of the polymerization reactor were coated, prior to polymerization, with a polar organic compound, such as an organic dye, and a polar organic compound exemplified by amino compounds, quinone compounds, aldehyde compounds and the like (see US Patent No. [deg.] 3,669,946).

  
Although it is extremely effective in preventing the deposition of polymer crusts or encrustations, the aforementioned coating process uses polar organic compounds in the form of a solution in an organic solvent and, therefore, cannot be dissociated. disadvantageous safety and toxicity problems which arise during the handling inherent in the use of an organic solvent, while when using

  
water as the solvent instead of the organic solvent, the effectiveness of preventing the deposition of polymer scale or crust is reduced to such an extent that the method is no longer practical.

  
Moreover, the aforementioned method of coating with a polar organic compound is rather inefficient when carrying out an emulsion polymerization or a polymerization involving an emulsifying agent in the polymerization mixture for the preparation. prevention of incrustal deposit

  
 <EMI ID = 6.1>

  
efficiency of this process during the implementation of a suspension polymerization in an aqueous medium for the polymerization of vinyl chloride,

  
 <EMI ID = 7.1>

  
composed of these monomers.

  
Unlike the polymerization of vinyl chloride for which one can usually

  
employ stainless steel polymerization reactors, such stainless steel polymerization reactors cannot be used for emulsion polymerization of styrene and for copolymerization of styrene and butadiene or acrylonitrile, styrene and butadiene or the like, due to the extraordinarily high proportion

  
deposit of encrustations or polymer crusts on

  
the walls of the reactor. In such cases, we use

  
glass-lined polymerization reactors despite certain drawbacks they entail,

  
as poor heat transfer coefficient and shorter service life, such as

  
also the difficulty of manufacturing a reactor with a large volume due to the poor workability of the glass jacket or packing.

  
The process described in the patent application

  
from the United States of America mentioned above is effectively effective for suspension polymerization

  
vinyl chloride, but no effect can be expected of preventing the deposit of crusts or encrustation during the polymerization of these monomers, during the use of the .procédé in question.

  
In order to overcome the aforementioned problems of the prior art, improved methods have been discovered, such as those described in Belgian patents n [deg.] 837,056, 844,215 and 845,168, according to which the internal walls of the polymerization reactor are coated or coated. and other surfaces. coming into contact with the monomer (s), a polar organic compound, for example, an organic dye, or a specific combination of two types of polar organic compounds with an optional mixture based on a metal salt and how to follow this coating or this coating, if it turns out

  
 <EMI ID = 8.1>

  
coated with an oxidizing agent or a reducing agent. The aforementioned methods described in the Belgian patents use, in most cases, the coating or coating liquid in an organic solvent, such as methyl alcohol, ethyl alcohol, toluene, methylene chloride, dimethylformamide and the like and, consequently, the disadvantages associated with the use of organic solvents cannot be avoided, even if the effectiveness of preventing the deposition of polymer crusts or encrustation is satisfactory. When water is used as a solvent instead of organic solvents, the effect of preventing the deposition of polymer crusts or encrustations is clearly more reduced, as demonstrated by the examples of the aforementioned Belgian patents.

  
As emerges from the above, it

  
It is well established that the deposition of polymer crusts or encrustations is reduced to a significant extent by coating or embedding the internal walls of the polymerization reactor with an organic solution of polar organic compounds -, such as organic dyes , while, on the other hand, we

  
hitherto no satisfactory process is known by which the internal walls are coated

  
of the polymerization reactor of an aqueous coating liquid to obtain a prevention of the deposition of polymer crusts or encrustations just as effective as in the case of the use of organic coating liquids. This is probably due to

  
the difficulty of forming water-insoluble coating layers having an effect of preventing the deposition of polymer crusts or encrustations on the internal walls of the polymerization reactor, when the coating liquid consists of a solution aqueous or an aqueous dispersion.

  
The subject of the present invention is therefore a new and improved process for the polymerization of vinyl monomers, according to which the deposition of polymer crusts or encrustation

  
on the surfaces of the polymerization equipment, known as the internal walls of the polymerization reactor, is effectively prevented by coating or coating

  
the surfaces in question of an aqueous coating liquid, instead of employing, for this purpose, coating liquids based on organic solvents, as was the case with the prior art processes.

  
The present invention also relates to

  
a process for the polymerization of vinyl monomers, characterized in that, before proceeding with the polymerization, the internal surfaces of the

  
 <EMI ID = 9.1>

  
equipment for the polymerization of an aqueous coating liquid and then proceeded to drying in a

  
 <EMI ID = 10.1>

  
water on the aforementioned surfaces for the purpose of erasing preventing the deposit of encrustations or crusts

  
of polymer on the surfaces concerned.

  
The present invention also relates to a

  
process for the preparation of polymer products, such as

  
a premium quality polyvinyl chloride resin.

  
The present invention also relates to a process for the polymerization of vinyl monomers, according to which the dep8t of encrustations or polymer crusts is effectively prevented independently.

  
types of polymerization carried out, such as suspension polymerization, emulsion polymerization, bulk polymerization and the like,

  
whether the polymerization is of the homopolymerization type or of the copolymerization type and independently of the

  
type of polymerization initiator and independently of the additives to be added to the polymerization mixture.

  
The objectives of the present invention are satisfactorily achieved by coating or coating, before proceeding with the introduction of the polymerization ingredients into the polymerization reactor, the internal walls and all other surfaces coming into contact with the polymerization reactor (s). mono-mer, an aqueous coating liquid containing

  
at least one of the alkali metal or ammonium salts of anionic dyes of the sulfonic acid forms

  
or carboxylic acid, the pH value being adjusted

  
to about 7 or less than 7, this coating or coating being followed by drying.

  
The method according to the present invention,

  
as described above, is so effective that the amount of deposition of polymer scale or crusts is surprisingly reduced on the various surfaces coming into contact with the monomer (s), such as

  
the internal walls of the polymerization reactor, the surfaces of the agitator blades and drive shafts and the like and this process efficiency is not dependent on the influences of the types of polymerization, e.g. suspension polymerization, emulsion polymerization , bulk polymerization and the like, types of the vinyl monomers to be polymerized, the composition of the polymerization mixture, etc. In addition, the efficiency of the process

  
is felt both in stainless steel polymerization reactors and in glass-lined polymerization reactors. Consequently, the implementation of the process according to the present invention makes it possible very advantageously to use a stainless steel polymerization reactor to proceed with the polymerization, the use of such a stainless steel reactor practically not being possible when the implementation of the processes of the prior art, due to the excessively large proportion of deposition of encrustations or polymer crusts on the walls and the equipment of the reactor

  
in question. The process according to the present invention is also advantageous in that it avoids the problems inherent in the use of organic solvents, such as the health problems of workers posed.

  
by the toxicity of the solvents and the possible risks of fire due to the flammability of the organic solvents, given that the process according to the present invention uses an aqueous coating liquid.

  
The mechanism by which the prevention of the deposition of polymer crusts or encrustations is obtained when carrying out the process according to the present invention probably lies in the fact that the adhesion of the films formed by the drying of the coating liquid on the affected surfaces is very strong due to the insolubility or extremely low solubility in water

  
film-forming substances originally present in the coating liquid and that, therefore, the films formed can effectively prevent adsorption, although not fully understood, of all types of dissociated and undissociated compounds from the mixture of polymerization on the surfaces of the reactor and its equipment, whatever the

  
type of polymerization.

  
We will now describe the process according to

  
the present invention in more detail.

  
Anionic dyes are the sulfonic acid or carboxylic acid forms which can be used for carrying out the process according to the present invention in the form of alkali metal or ammonium salts.

  
not exhaustive below:

  
(1) Dyes in the form of sulfonic acid:
C.I. Acid Yellow 38, C.I. Food Yellow 3, CI Reactive Yellow. 3, C.I. direct orange 2, orange

  
direct C.I. 10, acid red C.I. 18, acid red C.I. 52,

  
 <EMI ID = 11.1>

  
mordant violet CI 5, direct blue CI 6, direct blue CI 71, direct blue CI 106, reagent blue CI 2, reagent blue CI 4, reagent blue CI 18, acid blue CI 116, acid blue CI 158, acid black CI 1 , acid black CI 2, direct black CI 38, solubilized tank black; CI 1, fluorescent brightener C.I. 30, fluorescent brightener

  
 <EMI ID = 12.1>

  
C.I. Acid Blue 59, C.I. Acid Blue 113, C.I. Acid Orange 7, C.I. Direct Blue 1, C.I. Direct Blue 86, C.I. Direct Orange 26, C.I. 31 Direct Red, C.I. 19 Direct Black, C.I. 32 Direct Black, C.I. Direct Black
77, C.I. Direct Green 1, C.I. Acid Orange 3, C.I. Acid Black 124, C.I. Acid Black 52, and Acid Red

  
 <EMI ID = 13.1>

  
(2) dyes in the carboxylic acid form and dyes in both the sulfonic acid forms

  
 <EMI ID = 14.1>

  
Direct C.I. yellow 1, C.I. direct red 1,

  
biting black C.I. 5, azo brown C.I. 2, direct brown C.I. 1, direct brown C.I. 101, direct green C.I. 26, acid red C.I. 87, biting yellow C.I. 26, direct brown C.I. 37 and direct orange C.I. 97.

  
The aforementioned anionic dyes will be referred to as components in the remainder of this specification.
(at).

  
The aqueous solution of component (a) in a relatively low concentration of about 0.1 to 1% in. weight has a pH value of about 10. Such an alkaline aqueous solution of component '(a)

  
may not have a satisfactory effect of preventing the deposition of polymer crusts or encrustations when applied to the internal walls of the reactor and followed by drying to produce films coating on the surface of the walls in question. It is essential for the purposes of the present invention to adjust the pH of the aqueous solution of component (a) to

  
a value of about 7 or less than 7 or, more preferably, a value of about 5 or less than 5, by the use of a pH adjusting agent.

  
The pH adjusting agents to be used for adjusting the pH value of the aqueous solution or dispersion of component (a) are illustrated by various types of organic and inorganic acids, such as sulfuric acid, l hydrochloric acid, phosphoric acid, nitric acid, carbonic acid, perchloric acid, molybdic acid, tungstic acid, formic acid, acetic acid, oxalic acid, l 'lactic acid, maleic acid, glycolic acid, thioglycolic acid, phytic acid and the acid salts of these acids, if

  
are available. Among the aforementioned compounds, the most advantageous are sulfuric acid, phosphoric acid, nitric acid, molybdic acid, lactic acid, glycolic acid, thioglycolic acid, phytic acid and theirs. acid salts, if available, from the standpoint of obtaining the best results in preventing the deposition of polymer crusts or encrustations. These pH adjusting agents are conveniently used in the form of an aqueous solution.

  
The aqueous coating liquid to be applied

  
on the internal walls of the reactor is prepared

  
 <EMI ID = 15.1>

  
in water, dissolving or dispersing followed by the addition of the above-mentioned pH adjusting agent to bring the pH value of the aqueous liquid to about 7 or less. The concentration of component (a) i

  
in the coating liquid preferably ranges from about 0.01 to about 5% by weight, taking

  
considering the solubility of component (a)

  
in water, workability during operation

  
coating using the coating liquid and lowering the solubility of component (a) in

  
water when the pH value is lowered to 7

  
or less.

  
The aqueous coating liquid thus prepared having a pH value of 7 or less than 7,

  
is applied to the inner walls of the reactor and

  
on other surfaces of the reactor equipment

  
to be subsequently dried so as to generate a coating film having a preventive effect

  
deposit of polymer crusts or encrustations.

  
It is recommended that the workability of the aqueous coating liquid or the spreading of the coating liquid on the above surfaces be improved.

  
 <EMI ID = 16.1>

  
 <EMI ID = 17.1>

  
valent having 3 to 5 carbon atoms per molecule. Monovalent alcohol suitable for this purpose

  
is illustrated by the following substances: n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, tert-amyl alcohol, isoamyl alcohol, sec-amyl alcohol and the like, of which isobutyl alcohol is preferred because of its less unpleasant odor.

  
The addition of monovalent alcohol to the liquid

  
 <EMI ID = 18.1>

  
improvement of the workability during the coating operation, but also by the fact that it further improves the prevention of the deposition of polymer crusts or encrustations.

  
The use of methyl alcohol or alcohol

  
 <EMI ID = 19.1>

  
expected, while the use of a monovalent alcohol with a molecule containing more than 5 carbon atoms is not suitable due to the low water solubility of the alcohol in question.

  
The efficiency of the process according to the present invention is also improved by the addition of a water-soluble cationic dye having, per molecule, at least one pair of conjugated double bonds and at least one nitrogen atom (compound which will be called in the remainder of this specification component (b)), or a silicate or a silicic acid soluble in water or a water-soluble salt of metals other than alkali metals (referred to in the continuation of the present memory component (c)), in combination with component (a).

  
The addition of component (b) to the coating liquid is effective in that it reduces

  
the amount of coating eL in that it allows the drying temperature to be lowered to generate coating films of sufficient durability with full effectiveness of preventing the deposition of polymer crusts or encrustations.

  
On the other hand, component (c) added to the coating liquid is effective in that it improves

  
the durability of the coating films on the surface of the walls of the reactor and of the components which equip

  
the reactor.

  
Water-soluble cationic dyes which are suitable as component (b) include water-soluble azine dyes, such as

  
C.I. 2 basic red, C.I. 16 basic blue,

  
C.I. 2 basic black and the like; water soluble acridin dyes, such as C.I. 14 basic orange, C.I. 15 basic orange and the like; water soluble triphenylmethane dyes such as C.I. 1 basic blue, C.I. basic violet 3, C.I. basic blue 26, C.I. basic violet 14, C.I. basic blue 5, C.I. basic blue 7 and the like; water-soluble thiazine dyes, such as C.I. 9 basic blue,

  
C.I. Basic Yellow 1, C.I. Basic Blue 24, C.I. Basic Blue 25, C.I. Basic Green 5 and the like; water soluble methine dyes, such as C.I. 12 basic red, C.I. 11 basic yellow and the like; water soluble diphenylmethane dyes, such as C.I. 2 basic yellow and the like; xanthenic dyes

  
 <EMI ID = 20.1>

  
10, C.I. 1 basic red and the like; water-soluble azo dyes, such as C.I. 2 basic orange, C.I. 1 basic brown and the like; and water-soluble oxazine dyes, such as

  
 <EMI ID = 21.1>

  
analogues.

  
Compounds which are suitable as a component
(c) for the purposes of the present invention are illustrated by silicates or silicic acids soluble in water, such as orthosilicic acid, metasilicic acid, meso-disilicic acid, meso-trisilicic acid, meso-tetrasilicic acid, sodium metasilicate, sodium orthosilicate, sodium disilicate, sodium tetrasilicate, potassium metasilicate, hydrogenated potassium disilicate, lithium orthosilicate, orthodisilicate hexalithium, glass

  
soluble, 12-silicotungs &#65533; ic acid, iso-12-silicotungstic acid, 10-silicotungstic acid, potassium 12-silicotungstate, potassium iso-12-silico-tungstate, 10 - potassium silicotungstate, sodium 12-silicotungstate, acid

  
 <EMI ID = 22.1>

  
sodium silicomolybdate and the like; and water soluble salts, such as salts of oxyacids, acetic acid, nitric acid, hydroxides and halides of metals belonging to alkaline earth metals, for example magnesium, calcium, barium and the like; metals of the zinc group, for example zinc and the like; metals from the aluminum group, for example aluminum; of metals

  
from the group of tin, for example titanium, tin

  
and the like; metals of the iron group, for example, iron, nickel and the like; of group metals

  
chromium, for example chromium, molybdenum and the like; metals of the manganese group, for example manganese; metals of the copper group, for example copper, silver and the like; and platinum group metals, for example platinum.

  
When using component (b) or component (c) in combination with component (a),

  
the weight ratio of component (b) or (c) to component (a) preferably varies from 100: 0.1 to
100: 1000 or, more preferably, from 100: 3 to 100: 100, in order to obtain a strong adhesion of the coating films to the internal walls of the polymerization reactor. The total concentration of components (b) and / or (c) and component (a) in the aqueous coating liquid is preferably of the same order

  
of magnitude, that is to say that it varies from 0.01 56

  
at 5% by weight, as in the case of the coating liquid with component (a) alone.

  
In any event, the pH of the aqueous coating liquid should, in accordance with the present invention, be about 7 or less than 7. This is the

  
case because the coating films obtained in the case of using an alkaline coating liquid with a pH greater than 7, for example of

  
10 or of an approximate value, and following the application of drying, may dissolve on contact with an aqueous medium, thus showing

  
less satisfactory polymer crusting or encrusting prevention effect. Furthermore, when the ingredients present in the coating liquid according to the present invention, i.e. components (a) to (c), are used

  
as an organic solution, the resulting coating films are also soluble when they come into contact with an aqueous medium, also leading to less satisfactory effectiveness of the scale deposition prevention effect or

  
polymer crusts.

  
Probably the following is the mechanism by which a coating film with significantly improved polymer scab or scale deposition prevention efficiency by the use of an acidic coating liquid is obtained.

  
The water-soluble anionic dye forming component (a) has at least one group expressed by the formula -S03M or -COOM, where M represents an alkali metal or ammonium ion, which is in an undissociated state in solution. organic but which dissociates in an aqueous solution according to the following equations representing the dissociation equilibrium:

  

 <EMI ID = 23.1>


  
When the pH value of the solution is brought to 7 or less than 7 by the addition of the above mentioned pH adjusting agent to the solution at equilibrium, a new equilibrium is established according to the following equations. :

  

 <EMI ID = 24.1>


  
Due to the very low concentration of component (a) in the coating liquid (i.e. 0.01% to 5% by weight), no precipitate is formed by lowering the pH value during l adding the pH adjusting agent to a value of 7 or less than 7, or more preferably 5 or less than 5.

  
Drying the coating liquid applied to the surfaces removes water from the liquid in question and therefore the balance expressed by equations (3) and (4) slips to the right and results in the formation of insoluble coating films. or very hardly soluble in water, thus exerting an excellent effect of preventing the deposition of polymer crusts or encrustations.

  
During the implementation of the conforming process

  
In the present invention, the internal walls of the polymerization reactor and other surfaces which come into contact with the monomer (s), are first coated or coated with the aqueous coating liquid and are then dried by heating to

  
 <EMI ID = 25.1>

  
aqueous coating liquid on surfaces

  
 <EMI ID = 26.1>

  
In any event, the coated surfaces should be sufficiently dry before they are washed at 1: 1, followed by a subsequent polymerization cycle carried out in a conventional manner. The amount of coating on the reactor walls and other surfaces that are part of the reactor equipment

  
 <EMI ID = 27.1>

  
approximately the same as that used when

  
the use of prior art processes using certain types of coating materials. It is in particular possible to obtain an effect of preventing the deposition of sufficiently powerful polymer crusts or encrustations with a quantity of coating greater than 0.001 g / m, as dried on the walls.

  
reactor and agitator surfaces and the like.

  
The efficiency of the process according to the present invention is not limited to any particular types of polymerization. Therefore, the method according to the present invention is effective when carrying out any types.

  
polymerization, including suspension polymerization, emulsion polymerization and poly-

  
 <EMI ID = 28.1>

  
The prevention of the deposition of polymer crusts or encrustation is also not influenced by the additives conventionally introduced into the polymerization mixture, such as suspending agents, for example, partially saponified polyvinyl alcohol, methylcellulose and analogues; anionic surfactants, for example sodium laurylsulfate, sodium dodecylbenzene sulfonate, sodium dioctylsulfosuccinate and the like; nonionic surfactants, for example sorbitan monolaurate, polyoxyethylene alkyl ethers and the like; fillers, for example calcium carbonate, titanium dioxide and the like; stabilizers, for example, tribasic lead sulfate, calcium stearate, dibutyltin dilaurate, dioctyltin mercaptide and the like;

   lubricants, for example rice wax, stearic acid and the like; plasticizers, for example dioctyl phthalate, dibutyl phthalate and the like; chain transfer agents, for example trichlorethylene, mercaptans and the like; pH adjusting agents; polymerization initiators, for example

  
 <EMI ID = 29.1>

  
2,4-dimethylvaleronitrile, lauroyl peroxide,

  
potassium persulfate, cumene hydroperoxide, p-menthane hydroperoxide and the like.

  
 <EMI ID = 30.1>

  
The process according to the present invention also comprises vinyl halides, such as vinyl chloride, vinyl esters, such as acetate

  
vinyl and vinyl propionate, acrylic acid, methacrylic acid and esters and salts of these compounds, maleic acid, fumaric acid, and

  
their esters and anhydrides, dine monomers, such as butadiene, chloroprene and isoprene,

  
styrene, acrylonitrile, vinylidene halides and vinyl ethers.

  
The process according to the present invention is very particularly suitable for a heterogeneous free-radical polymerization according to which

  
the polymer formed separates from the polymerization mixture as the polymerization reaction proceeds. A typical case of such kind of polymerization is the preparation of homo- or

  
of co-polymers of a vinyl halide, a vinylidene halide or a mixture of a monomer mainly composed of a vinyl halide and a vinylidene halide, by polymerization in

  
 <EMI ID = 31.1>

  
The method according to the present invention

  
is also effective in preventing the deposit of

  
polymer crusts or encrustation on the walls

  
of stainless steel polymerization reactors

  
in which polymerization of styrene, methyl methacrylate, acrylonitrile and the like takes place, in which rubber latexes, such as SBR rubber and NBR rubber, are prepared by emulsion polymerization and in which

  
the preparation of ABS resins takes place.

  
Control tests and examples in accordance with

  
to the present invention which follow serve to illustrate the implementation of the method according to the present invention in more detail. It is obvious that the examples do not limit the invention in any way. In the table relating to each example, the experiment masked with an asterisk relates to the control test and the experiment without an asterisk is in accordance with the present invention.

Example 1

  
To carry out this example, a stainless steel polymerization reactor with a capacity of 100 liters, equipped with a stirrer, was used. An aqueous coating liquid was prepared by dissolving C.I. 2 acid black in a concentration

  
 <EMI ID = 32.1>

  
indicated in Table I by the use of sulfuric acid. The internal walls of the

  
the polymerization reactor and the stirrer surface of the coating liquid prepared as described above, in an amount of 0.1 g / n (in the dried state), the coating being followed by drying in the conditions appearing in Table I and washing with water. 26 kg of vinyl chloride monomer, 52 kg of deionized water, 26 g of partially saponified polyvinyl alcohol and 8 g of a, a'-azobis-2,4-dimethylvaleronitrile were introduced into the polymerization reactor thus treated. and the polymerization was carried out by heating the polymerization mixture at 57 [deg.] C for 3 hours, with stirring.

  
After the completion of each polymerization cycle, the amount of polymer crusts or encrustation deposited on the walls of the reactor was determined so as to obtain the expressed results

  
 <EMI ID = 33.1>

  
 <EMI ID = 34.1>

  
influence of pH adjustment and drying conditions (temperature and time) on the formation of polymer crusts or encrustations. By referring more specifically to experiments 5 and 5 and comparing them to each other, it can be seen that

  
extending the drying time from 10 to 30 minutes reduced the formation of scabs

  
 <EMI ID = 35.1>

  
This can be interpreted as demonstrating that insufficient drying results in the prevention of the deposition of scabs or unsatisfactory polymer encrustation.

TABLE I

  

 <EMI ID = 36.1>


  
Note: r.t. is the ambient temperature.

Example 2

  
The inner walls of a 1000 liter stainless steel polymerization reactor and the surfaces of the stirrer were coated with an aqueous coating liquid in an amount of 0.1 g / m 2 (at dried state), prepared by dissolving an anionic dye (coating compound), as shown in Table II, in a concentration of 1% by weight, with a pH value as shown in

  
 <EMI ID = 37.1>

  
The pH also shown in Table II, the coating in question being followed by heat drying and vigorous washing with water.

  
200 kg of vinyl chloride monomer were introduced into the polymerization reactor thus treated,
400 kg of deionized water, 40 g of peroxy-dicarbonate

  
of diisopropyl, 250 g of partially saponified polyvinyl alcohol and 25 g of hydroxypropylmethyl cellulose and the polymerization reaction was carried out at a temperature of 57 [deg.] C, for
12 hours, with the agitator running. After the completion of the polymerization reaction, the polymerization mixture was taken out from the polymerization reactor and the reactor in question was washed with water and dried in order to determine the amount of crusts or encrustations of the polymer. polymer

  
 <EMI ID = 38.1>

  
appearing in Table II.

TABLE II

  

 <EMI ID = 39.1>
 

  

 <EMI ID = 40.1>
 

Example 3

  
The inner walls of a 1000 liter stainless steel polymerization reactor as well as the surfaces of the stirrer were coated with an aqueous coating liquid, in a concentration of 1% by weight, such as: 'indicated in Table III,

  
in an amount of 0.1 g / m2 (in the dried state).

  
Into the polymerization reactor thus treated, 200 kg of vinyl chloride monomer, 400 kg of deionized water and the other ingredients comprising the polymerization initiator and the dispersing agent as indicated in the table were introduced and were obtained. how the reaction proceeds

  
polymerization at a temperature of 57 [deg.] C, for
10 hours, with stirring. At the end of the aforementioned polymerization period, the mixture was discharged

  
polymerization of the reactor and the amount of polymer crusts or encrustations deposited on the walls of the reactor was determined, so as to obtain the results in g / m <2> appearing in Table III.

TABLE III

  

 <EMI ID = 41.1>


  
 <EMI ID = 42.1>

  
KPS = potassium persulfate

  
APS = ammonium persulfate

  
PPI = diisopropyl peroxy-dicarbonate

  
PVA = partially saponified polyvinyl alcohol

  
 <EMI ID = 43.1>

  
Na-DBS = sodium dodecylbenzene sulfonate

Example 4

  
The internal walls and other surfaces were lined with a combined plant consisting of a stainless steel polymerization reactor with a capacity of 2 liters of the vertical type and a stainless steel polymerization reactor with a capacity < EMI ID = 44.1>

  
 <EMI ID = 45.1>

  
as shown in Table IV in one concentration

  
 <EMI ID = 46.1>

  
 <EMI ID = 47.1>

  
under the conditions indicated in Table IV, washing with water and final drying.

  
800 g of chloride were introduced into the polymerization reactor with a capacity of 2 liters

  
 <EMI ID = 48.1>

  
diisopropyl and the polymerization reaction was carried out by heating at a temperature of 60 [deg.] C for

  
 <EMI ID = 49.1>

  
of 900 rpm. The polymerization mixture was then transferred from this polymerization reactor into the polymerization reactor with a capacity of 4 liters, previously loaded with 800 g of monomeric vinyl chloride and 0.4 g of diisopropyl peroxydicarbonate, then continued the polymerization reaction by heating to a temperature of 57 [deg.] C

  
 <EMI ID = 50.1>

  
speed of 100 rpm. After completion of the polymerization reaction, the polymerization mixture was discharged from the reactor and the amounts of deposited polymer crusts or encrustation were determined.

  
on the internal walls of the two polymerization reactors, the results obtained appearing in Table IV which follows.

TABLE IV

  

 <EMI ID = 51.1>

Example 5

  
The internal walls were lined with a glass-lined polymerization reactor with a capacity of

  
 <EMI ID = 52.1>

  
aqueous coating liquid, as specified in

  
 <EMI ID = 53.1>

  
a quantity of coating of 0.1 g / m <2> (in the dried state), this coating being followed by drying at 90 [deg.] C

  
for 10 minutes and a vigorous wash with water. In the polymerization reactor thus treated, one

  
introduced 20 kg of vinyl chloride monomer,

  
40 kg of deionized water, 13 g of potassium persulfate and 250 g of sodium laurylsulfate and the polymerization reaction was continued at a temperature of 50 [deg.] C, for 12 hours, with stirring. At the end of the aforementioned polymerization period, the

  
the reactor polymerization mixture and the amount of crusts or encrustation was determined

  
of polymer deposited on the walls of the reactor, <EMI ID = 54.1>

  
in Table V below.

TABLE V

  

 <EMI ID = 55.1>

Example 6

  
The walls of a 100 liter stainless steel polymerization reactor and the stirrer installed therein were preheated and a coating liquid as shown in Table VI was applied in one step. concentration

  
 <EMI ID = 56.1>

  
 <EMI ID = 57.1>

  
dried), the coating being followed by washing with water after drying the coating liquid. The polymerization reaction was carried out in the polymerization reactor thus treated under the same conditions as those described in Example 1. After the completion of the polymerization reaction, the amount of polymer crusts or encrustation deposited on the polymerization was determined. walls of the reactor, the results obtained being presented in Table VI below.

TABLE VI

  

 <EMI ID = 58.1>

Example 7

  
The internal walls of a reactor were coated

  
of polymerization in stainless steel, with a capacity of 400 liters as well as the surface of the related agitator, of a coating liquid as indicated in Table VII, in a concentration of 1% in

  
weight and in a coating amount of 0.1 g / m

  
(in the dried state), coating followed by drying

  
warm and wash off with water. 200 kg of deionized water, 100 kg of styrene monomer, 1 kg of calcium phosphate, 10 g of sodium dodecyl benzene sulphonate and 100 g of benzoyl peroxide were introduced into the polymerization reactor thus treated, and the

  
 <EMI ID = 59.1>

  
for 11 hours, with stirring. After the completion of the polymerization reaction, the quantity of polymer crusts or encrustations deposited on the walls of the reactor was determined, so as to obtain the results indicated in Table VII below, in g / m2.

TABLE VII

  

 <EMI ID = 60.1>

Example 8

  
 <EMI ID = 61.1>

  
7 as well as the surface of the agitator of a coating liquid as shown in Table VIII, in a concentration of 1% by weight and in an amount

  
 <EMI ID = 62.1>

  
being followed by hot drying and washing with water. Polymerization of styrene was carried out under the same conditions as described in Example 7 and, after completion of the polymerization reaction, the polymerization mixture was discharged from the reactor which was subsequently washed with water. We repeated

  
this cycle of operations and the polymerization cycles were noted during which the amount of crusts

  
 <EMI ID = 63.1>

  
the results obtained being presented in Table VIII.

TABLE VIII

  

 <EMI ID = 64.1>

Example 9

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 400 liters, as well as the surface of the stirrer, were coated with a coating liquid as presented in the

  
 <EMI ID = 65.1>

  
this coating being followed by hot drying and

  
washing with water. 180 kg of deionized water were introduced into the polymerization reactor thus treated,

  
75 kg of 1,3-butadiene monomer, 25 kg of styrene monomer, 4.5 kg of sodium lauryl sulphate, 280 g

  
of tert-dodecylmercaptan and 300 g of potassium persulfate and the polymerization reaction was carried out

  
 <EMI ID = 66.1>

  
restlessness. After the completion of the polymerization reaction, the amount of polymer crusts or encrustations deposited on the walls of the reactor was determined so as to obtain the results in g / m <2> presented in. table 9 below.

  
TABLE 9

  

 <EMI ID = 67.1>

Example 10

  
The internal walls of a reactor were coated

  
 <EMI ID = 68.1>

  
of 400 liters as well as the surface of the agitator of a coating liquid as indicated in Table 10, in a concentration of 1% by weight and in an amount of coating of 0.1 g / m <2> (in dried state), coating followed by heat drying and water washing.

  
180 kg of deionized water, 74 kg of monomeric 1,3butadiene, 26 kg of monomeric acrylonitrile, were introduced into the polymerization reactor thus treated,

  
4 kg of sodium oleate, 1 kg of oleic acid, 500 g

  
of tert-dodecyl mercaptan, 100 g of sodium pyrophosphate and 300 g of sodium persulfate and the polymerization reaction was carried out at a temperature of

  
 <EMI ID = 69.1>

  
completion of the polymerization reaction, the amount of polymer crusts or encrustation deposited on the walls of the reactor was determined by obtaining

  
 <EMI ID = 70.1>

  
TABLE 10

  

 <EMI ID = 71.1>

Example 11

  
The internal walls of a glass-lined polymerization reactor, with a capacity of 400 liters, were coated, as well as the surface of the agitator, with a coating liquid as indicated in the

  
 <EMI ID = 72.1>

  
 <EMI ID = 73.1>

  
this coating being followed by hot drying and washing with water. 180 kg of deionized water, 40 kg of monomeric 1,3-butadiene, 54 kg of monomeric methyl methacrylate, 4 kg of monomeric styrene, 4.5 kg of laurylbenzene sulphonate were introduced into the polymerization reactor thus treated. sodium, 280 g of tertdodecylmercaptan and 300 g of potassium persulfate

  
and the polymerization reaction was carried out at a temperature of 50 [deg.] C for 10 hours, with stirring. After the completion of the polymerization reaction, the amount of polymer crusts or encrustation deposited on the walls of the reactor was determined, so as to obtain the results presented in Table 11, in g / m <2>.

  
TABLE 11

  

 <EMI ID = 74.1>

Example 12

  
 <EMI ID = 75.1>

  
(coating compound) as indicated in the table

  
 <EMI ID = 76.1>

  
with subsequent adjustment of the pH value by the addition of a pH adjusting agent indicated in the table and addition of a monovalent alcohol also indicated in the table, in an amount indicated

  
in parts by weight per 100 parts by weight of the aqueous solution obtained by dissolving the dye in water.

  
The internal walls of a stainless steel polymerization reactor with a capacity of 1000 liters were coated as well as the surface of the agitator.

  
coating liquid thus prepared in a coating amount of 0.1 g / m <2> (in the dried state), the coating being followed by heat drying

  
 <EMI ID = 77.1>

  
200 kg of vinyl chloride monomer, 400 kg of deionized water, 250 g of partially saponified polyvinyl alcohol, 25 g of hydroxypropylmethyl cellulose and 75 g of diisopropyl peroxydicarbonate were introduced into the polymerization reactor thus treated. to the polymerization reaction at a temperature of 57 [deg.] C for 10 hours, with stirring.

  
After the completion of the polymerization reaction, the amount of polymer crusts or encrustations deposited on the walls of the

  
 <EMI ID = 78.1>

  
presented in Table 12. Among others, experiments n [deg.] 87 and n [deg.] 88 show that the use of methanol or ethanol resulted in a formation

  
somewhat higher crusts or encrustation

  
in comparison to other experiments in which other alcohols having a higher quantity of carbon atoms were used. In addition, Experiments Nos. 89 and 90 in which surfactants were used instead of monovalent alcohols reveal that surfactants have a deleterious effect on preventing the deposition of crusts or encrustations. of polymer.

  
TABLE 12

  

 <EMI ID = 79.1>
 

  

 <EMI ID = 80.1>

Example 13

  
Each of the anionic dyes was dissolved
(compound (a)) with its CI designation), cationic dyes (compound (b) with their CI designations) and pH adjusting agents, as listed in Table 13, in water ,

  
in quantities such that a concentration

  
 <EMI ID = 81.1>

  
 <EMI ID = 82.1>

  
indicated in the same table by the addition of the pH adjusting agent. We coated the internal walls

  
a stainless steel polymerization reactor,

  
with a capacity of 100 liters, of the coating liquid prepared above and the suspension polymerization of the vinyl chloride monomer was undertaken under conditions substantially identical to those described in Example 1, except that the amount of coating was

  
 <EMI ID = 83.1>

  
upon completion of the polymerization reaction, the amount of polymer crusts or encrustation deposited on the walls of the reactor was determined, so

  
 <EMI ID = 84.1>

  
in Table 13.

  
TABLE 13
 <EMI ID = 85.1>
 
 <EMI ID = 86.1>
 Note: in the column "pH adjustment agent":

  
 <EMI ID = 87.1>

  
P2 = sodium salt -2 de- phytic acid

  
 <EMI ID = 88.1>

Example 14

  
Each of the anionic dyes was dissolved
(compounds (a) with their CI designation), cationic dyes (compounds (b) with their IC designation) and pH adjusting agents, as given in Table 14, in water, in amounts such that a total concentration of these three compounds of about 0.1% by weight is obtained and the pH of the solution is adjusted to the value indicated in the table

  
concerned by the addition of the pH adjusting agent;

  
The walls of a polymerization reactor made of stainless steel, with a capacity of 120 liters, as well as the surface of the stirrer were coated with liquid.

  
 <EMI ID = 89.1>

  
 <EMI ID = 90.1> heat drying and vigorous washing with water.

  
In the polymerization reactor thus treated, were introduced 50 kg of monomeric styrene, 43.2 kg of water

  
 <EMI ID = 91.1>

  
sodium sulfite, 125 g of benzoyl peroxide and 25 g of tert-butyl perbenzoate and the polymerization reaction was carried out at a temperature of 90 [deg.] C, for

  
7 hours, with stirring. After the completion of the polymerization reaction, the amount of crusts was determined.

  
or polymer encrustations deposited on the walls of the reactor so as to obtain the results indicated in

  
Table 14.

  
TABLE 14
 <EMI ID = 92.1>
 
 <EMI ID = 93.1>
 Note: In the column "pH adjustment agent":

  
 <EMI ID = 94.1>

  
 <EMI ID = 95.1>

  
 <EMI ID = 96.1>

Example 15

  
Each of the anionic dyes was dissolved
(compounds (a) with their IC designation.), cationic dyes (compounds (b) with their IC designation) and pH adjusting agents, as listed in Table 15, in water , in amounts such that a total concentration of

  
 <EMI ID = 97.1>

  
adjusted the pH of the solution to the value indicated in

  
Table 15 by adding the desired pH adjusting agent. The internal walls of a polymerization reactor in stainless steel, with a capacity of 400 liters, as well as the surfaces of the stirrer were coated,

  
of the coating liquid thus prepared, in an amount

  
coating of 0.01 g / m <2> (in the dried state), this coating being followed by heat drying and washing with water.

  
80 kg of monomeric vinylidene chloride, 20 kg of monomeric vinyl chloride, 200 kg of deionized water, 150 g of benzoyl peroxide, 125 g of alcohol were introduced into the polymerization reactor thus treated.

  
 <EMI ID = 98.1>

  
cellulose and the polymerization reaction was carried out at a temperature of 60 [deg.] C for 12 hours, with stirring. After the completion of the polymerization, the amount of polymer crusts or encrustations deposited on the walls of the reactor was determined so as to obtain the results presented in Table 15.

  
Table 15

  

 <EMI ID = 99.1>


  
Note: In the column "pH adjustment agent"

  
 <EMI ID = 100.1>

  
P2 = sodium-2 salt of phytic acid

Example 16

  
The internal walls were lined with a stainless steel polymerization reactor, with a capacity

  
 <EMI ID = 101.1>

  
a coating liquid as indicated in the table
16, in a concentration of 0.1% by weight and in a

  
 <EMI ID = 102.1>

  
this coating being followed by hot drying and washing with water.

  
50 kg of styrene monomer, 50 kg of water were introduced into the polymerization reactor thus treated.

  
 <EMI ID = 103.1>

  
saponified, 25 g of methylcellulose and 150 g of peroxide

  
of benzoyl and the polymerization reaction was carried out at a temperature of 90 [deg.] C for 7 hours, under

  
 <EMI ID = 104.1>

  
risation, the amount of polymer crusts or encrustations deposited on the walls of the reactor was determined, so as to obtain the results presented in Table 16 below.

  
TABLE- 16

  

 <EMI ID = 105.1>

Example 17

  
The internal walls of a polymerization reactor in stainless steel, with a capacity of 250 liters, were coated, as well as the surface of the stirrer,

  
a coating liquid as indicated in the table
17, in a concentration of 0.1% by weight and in a

  
 <EMI ID = 106.1>

  
this coating being followed by hot drying and vigorous washing with water.

  
60 kg of monomeric styrene, 40 kg of monomeric acrylonitrile, 100 kg of deionized water, 2 kg of hydroxyapatite, 40 g of sodium urylsulphate, 300 g of tert. -dodecylmercaptan and 400 g of lauroyl peroxide. The polymerization reaction was carried out by gradually raising the temperature starting

  
 <EMI ID = 107.1>

  
from 70 [deg.] C to 80 [deg.] C over about 2 hours and finally at 80 [deg.] C for 1 hour, so as to prepare the copolymer of styrene and acrylonitrile. After the completion of the polymerization reaction, the amount was determined.

  
polymer crusts or encrustations deposited on the walls of the reactor, so as to obtain the results presented in Table 17 below.

  
TABLE 17

  

 <EMI ID = 108.1>
 

Example 18

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 1000 liters, as well as the surface of the necessary stirrer were coated with a coating liquid as indicated.

  
 <EMI ID = 109.1>

  
weight and amount of coating 0.01 g / m <2>

  
(in a dried state), this coating being followed by heat drying and vigorous washing with water.

  
200 kg of vinyl chloride were introduced into the polymerization reactor thus treated.

  
 <EMI ID = 110.1>

  
proceeded with the polymerization reaction at a temperature of 57 [deg.] C, for 12 hours, with stirring.

  
After the completion of the polymerization reaction, the reaction mixture was discharged from the reactor which was subsequently washed with water and repeated.

  
the polymerization cycles under the same conditions as those described above so as to note the number of polymerization cycles carried out without exceeding a deposit of polymer crusts or encrustations of

  
1 g / m. The results obtained appear in Table 18 below.

  
TABLE 18

  

 <EMI ID = 111.1>

Example 19

  
The same experimental procedures were repeated as described in Example 13, except that the coating liquids were used in admixture with a monovalent alcohol, as indicated in

  
Table 19, in order to obtain the results

  
deposition of polymer crusts or encrustations also presented in the table. In these experiments, the coated surfaces were dried by heating at 50 ° C. for 10 minutes.

  
The addition of monovalent alcohol to the liquid

  
coating has been found to be effective in improving the spread of the coating liquid on the stainless steel surfaces of the reactor, thereby allowing

  
the implementation of an easy coating operation.

  
TABLE 19

  

 <EMI ID = 112.1>


  
Note: the percentages are all by weight.

Example 20

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 100 liters, as well as the surfaces of the stirrer coming into contact with the monomer, were coated in an amount

  
0.1 g / m2 coating liquid, the coating liquid prepared by dissolving each of the anionic dyes (compounds (a) with their CI designation) and metal salts (components (c)) in water into one weight ratio as shown in Table 20

  
and in a total concentration of 1% by weight, the dissolution being followed by the adjustment of the pH value by the addition of hydrochloric acid and the coating then being dried by heating, a vigorous washing with water thereafter being convenient.

  
26 kg of monomeric vinyl chloride, 52 kg of deionized water, 26 g of alcohol were introduced into the polymerization reactor thus treated.

  
 <EMI ID = 113.1>

  
azobis-2,4-dimethylvaleronitrile and the polymerization reaction was carried out at a temperature of 57 [deg.] C for 8 hours, with stirring.

  
After the completion of the polymerization reaction, the amount of polymer crusts or encrustation deposited on the walls of the reactor was determined, so as to obtain the results shown in Table 20 which follows.

  
TABLE 20

  

 <EMI ID = 114.1>
 

  

 <EMI ID = 115.1>

Example 21

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 1000 liters, as well as the surfaces of the agitator, were coated with a coating liquid as indicated in the

  
 <EMI ID = 116.1>

  
tions shown in the table.

  
Into the polymerization reactor thus treated, 200 kg of vinyl chloride monomer, 400 kg of deionized water and other ingredients as indicated in the table were introduced, and the course of the polymerization reaction was carried out at a temperature. temperature of 57 [deg.] C, for 10 hours, the agitator being

  
Operating. After the completion of the polymerization reaction, the amount of crusts was determined.

  
or polymer encrustation deposited on the walls of the reactor, so as to obtain the results in g / m <2> as presented in the following table.

  
TABLE-21

  

 <EMI ID = 117.1>


  
Note: (**) Potassium stearate, 2.5 + rice wax; 3.0+

  
dioctyl tin mercaptide, 1.75 + polyethylene wax

  
 <EMI ID = 118.1>

  
LPO = laurel_peroxide

  
PPI = diisopropyl peroxy-dicarbonate

  
KPS = potassium persulfate

  
HPMC = hydroxypropylmethyl cellulose

  
SML = sorbitan monolaurate

  
PVA = partially saponified polyvinyl alcohol Na-LS = sodium lauryl sulphate Experiments n [deg.] 223 and 224 make it possible to demonstrate the effectiveness of the process in accordance with the present invention as regards the copolymerization of vinyl chloride and of acetate vinyl. The amount of vinyl chloride used was 200 kg in each experiment, while the amount of vinyl acetate was 10 kg in the experiment.
223 and 37.5 kg in experiment n [deg.] 224.

  
The internal walls and other surfaces of a combined installation consisting of a reactor

  
stainless steel curing unit, with a capacity

  
 <EMI ID = 119.1>

  
merization in stainless steel, with a capacity of

  
4 liters, horizontal type, coming into contact with

  
 <EMI ID = 120.1>

  
as shown in Table 22, in a concentration of 1% by weight and a coating amount of

  
0.1 g / m <2> (in the dried state), this coating being followed by heat drying, washing with water and final drying.

  
Into the vertical type polymerization reactor thus treated, 800 g of vinyl chloride monomer and 0.3 g of diisopropyl dicarbonate peroxide were introduced, and the polymerization reaction was carried out at a temperature of 60 deg. ] C for 2 hours with the stirrer driven at a speed of 900 rpm. The polymerization mixture was then transferred to the horizontal type polymerization reactor, previously loaded with 800 g.

  
of vinyl chloride monomer and 0.4 g of peroxy &#65533;

  
 <EMI ID = 121.1>

  
polymerization reaction at a temperature of 57 [deg.] C for a further 10 hours with the stirrer driven at a speed of 100 rpm. After the completion of the polymerization reaction, the quantities of polymer crusts or encrustation deposited on the internal walls of the two reactors were determined.

  
polymerization, so as to obtain the results in

  
 <EMI ID = 122.1>

  

 <EMI ID = 123.1>
 

Example 23

  
The internal walls were lined with a glass-lined polymerization reactor with a capacity of
100 liters, as well as the surface of the stirrer, of a coating liquid as shown in Table 23, in a concentration of 1% by weight and in an amount

  
 <EMI ID = 124.1>

  
being followed by heat drying and vigorous washing with water "

  
20 kg of vinyl chloride monomer were introduced into the polymerization reactor thus treated,

  
 <EMI ID = 125.1>

  
and 250 g of sodium lauryl sulfate and the polymerization reaction was carried out at a

  
 <EMI ID = 126.1>

  
After the completion of the polymerization reaction,

  
determined the amount of crusts or encrustations

  
of polymer deposited on the walls of the reactor, so as to obtain the results in g / m <2> presented in the following table.

  
TABLE 23

  

 <EMI ID = 127.1>
 

Example 24

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 100 liters, as well as the other parts of the agitator coming into contact with the monomer were previously heated and the surfaces thus heated were coated with a coating liquid as shown in Table 24 in a concentration of 1% by weight and

  
 <EMI ID = 128.1>

  
this coating being followed by direct washing with water. The polymerization of vinyl chloride was carried out under conditions substantially identical to those

  
 <EMI ID = 129.1>

  
polymerization, the amount of polymer crusts or encrustations deposited on the walls of the

  
 <EMI ID = 130.1>

  
presented in the following table.

  
TABLE 24

  

 <EMI ID = 131.1>
 

Example 25

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 400 liters, as well as the surfaces of the agitator coming into contact with the monomer, were coated with a coating liquid as shown in the table 25, in one

  
 <EMI ID = 132.1>

  
 <EMI ID = 133.1>

  
followed by hot drying and washing with water.

  
200 kg of deionized water, 100 kg of monomeric styrene, 1 kg of calcium phosphate, 10 g were introduced into the polymerization reactor thus treated.

  
 <EMI ID = 134.1>

  
benzoyl peroxide and the polymerization reaction was carried out at a temperature of 90 [deg.] C, for 11 hours, with stirring. After the completion of the polymerization reaction, the amount of polymer crusts or encrustations deposited on the walls of the reactor was determined, so as to obtain the results in g / m <2> presented in the following table.

  
TABLE 25

  

 <EMI ID = 135.1>

Example 26

  
 <EMI ID = 136.1>

  
merization than that used for carrying out Example 25 and the surfaces of the stirrer coming into contact with the monomer were coated with a coating liquid as indicated in the table
26 in a concentration of 1% by weight and in a

  
 <EMI ID = 137.1>

  
coating followed by hot drying and washing with water.

  
The polymerization reaction was carried out in the polymerization reactor thus treated under conditions substantially identical to those described in Example 25. After the completion of the polymerization reaction, the polymerization mixture was discharged from the reactor which was then discharged. then washed with water and the polymerization cycles repeated so as to note the number of polymerization cycles

  
 <EMI ID = 138.1>

  
1 g / m polymer inlays. The results thus obtained appear in Table 26.

  
TABLE 26

  

 <EMI ID = 139.1>

Example 27

  
The internal walls of a stainless steel polymerization reactor were coated with; capacity of 400 liters, as well as the surfaces of the agitator coming into contact with the monomer, of a coating liquid as indicated in table 27 in one

  
 <EMI ID = 140.1>

  
 <EMI ID = 141.1>

  
at the water.

  
180 kg of deionized water, 75 kg of monomeric 1,3-butadiene, 25 kg of monomeric styrene, 4.5 kg of sodium lauryl sulfate, 280 g of tertdodecyl mercaptan and 300 were introduced into the polymerization reactor thus treated. g of potassium persulfate and the polymerization reaction was carried out at a temperature of 50 [deg.] C for 12 hours, with stirring.

  
After the completion of the polymerization reaction, the amount of polymer crusts or encrustations deposited on the walls of the reactor was determined, so as to obtain the results in g / m <2> presented in the following table.

  
TABLE 27

  

 <EMI ID = 142.1>

Example 28

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 400 liters, as well as the surfaces of the agitator, were coated with a coating liquid as shown in Table 28, in a mixture. concentration of 1% by weight and <EMI ID = 143.1>

  
being followed by hot drying and

  
washing with water.

  
180 kg of deionized water, 74 kg of monomeric 1,3-butadiene, 26 kg of monomeric acrylonitrile, 4 kg of sodium oleate, 1 kg of oleic acid, were introduced into the polymerization reactor thus treated, 500 g of tert-dodecyl mercaptan, 100 g of sodium pyrophosphate and 300 g of potassium persulfate and the polymerization reaction was carried out at a temperature of 40 [deg.] C for 12 hours, with stirring. After the completion of the polymerization reaction, the amount of polymer crusts or encrustations deposited on the walls of the reactor was determined so as to

  
 <EMI ID = 144.1>

  
table below.

  
TABLE 28

  

 <EMI ID = 145.1>
 

Example 29

  
The internal walls of a glass-lined polymerization reactor, with a capacity of 400 liters, as well as the surfaces of the agitator, were coated with a coating liquid as shown in Table 29, in a batch. concentration of 1% by weight and in an amount of coating of 0.1 g / m (in the dried state), this coating being followed by heat drying and washing with water.

  
In the polymerization reactor as well

  
 <EMI ID = 146.1>

  
of monomeric 1,3-butadiene, 54 kg of monomeric methyl methacrylate, 4 kg of monomeric styrene, 4.5 kg of sodium laurylbenzene sulfonate, 280 g of tertdodecyl mercaptan and 300 g of potassium persulfate and the unwinding was carried out of the polymerization reaction at a temperature of 50 [deg.] C, for 10 hours, with stirring. After the completion of the polymerization reaction, the polymerization mixture was discharged from the reactor which was then washed with water and the amount of polymer crusts or encrustations deposited on the walls of the reactor was determined in such a manner. to obtain the results in g / m <2> presented in the following table.

  
TABLE 29

  

 <EMI ID = 147.1>

Example 30

  
The internal walls of a reactor were coated

  
 <EMI ID = 148.1>

  
of 200 liters, as well as the surfaces of the agitator, of a coating liquid as presented in the

  
 <EMI ID = 149.1>

  
washing with water.

  
In the polymerization reactor as well

  
treated, 30 kg of a polybutadiene latex with a solids content of 50%, 50 kg of monomeric styrene, 20 kg of monomeric acrylonitrile, 100 g of tert-dodecylmercaptan, 500 g of potassium oleate were introduced

  
and 500 g of potassium persulfate and one proceeded

  
during the course of the polymerization reaction

  
 <EMI ID = 150.1>

  
stirring, so as to obtain an ABS resin polymer emulsion. After the completion of the polymerization reaction, the amount of polymer crusts or encrustations deposited on the walls was determined.

  
 <EMI ID = 151.1>

  
presented in the following table.

  
TABLE 30

  

 <EMI ID = 152.1>

Example 31

  
We prepared revote sent liquids

  
aqueous solution by dissolving in each case an anionic dye (compound (a) bearing its designation of

  
CI) and a metal salt (compound (c)), in a total concentration of 0.1% by weight, dissolution followed by adjustment of the pH value with hydrochloric acid and the addition of a monovalent alcohol in an amount of 10 parts by weight based on 100 parts by weight of the aqueous solution

  
dye and metal salt -

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 100 liters, as well as the surfaces of the stirrer coming into contact with the monomer, were coated with the coating liquid thus prepared, in an amount of. coating of 0.1 g / m <2> (in the dried state), this coating being followed by heat drying and washing with water.

  
26 kg of vinyl chloride monomer were introduced into the polymerization reactor thus treated,
52 kg deionized water, 26 g polyvinyl alcohol

  
 <EMI ID = 153.1>

  
hours, with stirring. After the completion of the polymerization reaction, the amount of polymer crusts or encrustations deposited was determined.

  
on the walls of the reactor so as to obtain the results presented in the following table.

  
TABLE'31

  

 <EMI ID = 154.1>


  
 <EMI ID = 155.1>

  
 <EMI ID = 156.1>

  
A2 = sec-butyl alcohol

  
 <EMI ID = 157.1>

Example 32

  
The internal walls of a stainless steel polymerization reactor, with a capacity of 50 liters, as well as the surfaces of the stirrer coming into contact with the monomer, were coated with a coating liquid as shown in the Table 32 below, in a concentration of 1% by weight and in a

  
 <EMI ID = 158.1>

  
 <EMI ID = 159.1>

  
washing with water.

  
In the polymerization reactor as well

  
 <EMI ID = 160.1>

  
of monomeric styrene, 100 g of calcium phosphate,

  
10 g of sodium dodecyl benzene sulfonate and 10 g

  
of benzayl peroxide and the reaction was carried out

  
polymerization at a temperature of 90 [deg.] C, for

  
11 hours, with stirring.

  
After the completion of the polymerization reaction, the polymerization mixture was discharged from the reactor which was then washed with water and the polymerization cycles were repeated under the same conditions as described above in order to '' record the number of polymerization cycles carried out without exceeding a deposit of polymer crusts or encrustation of 1 g / m <2>. The results appear in Table 32 which follows.

  
TABLE 32

  

 <EMI ID = 161.1>
 

CLAIMS

  
1. Process for the polymerization of a vinyl monomer or of a mixture of vinyl monomers,

  
the polymerization being carried out in a polymerization reactor having a surface in contact with

  
said monomer or said mixture of monomers, characterized in that (1) the surface in question is coated, before

  
to polymerize an aqueous coating liquid containing at least one compound selected from

  
the group formed by alkali metal salts and

  
 <EMI ID = 162.1>

  
in water in the form of sulfonic acid or in the

  
carboxylic acid torso and possessing a pH, adjusts

  
by the use of an agent for adjusting the pH, not greater than 7 and (2) the surface thus coated is dried.


    

Claims (1)

<EMI ID = 163.1> characterized in that the aqueous coating liquid also contains a monovalent alcohol having 3 to 5 carbon atoms per molecule, in an amount from 1 to 20% by weight based on the above coating liquid. 3. Method according to any one of claims 1 and 2, characterized in that the concentration <EMI ID = 164.1> Water soluble anionic in the aqueous coating liquid ranges from 0.01 to 5% by weight. 4. Method according to any one of the preceding claims, characterized in that the pH value of the aqueous coating liquid is equal to or less than 5. 5. Method according to any one of the preceding claims, characterized in that one carries out the hot drying step, at a temperature of 40 to 100 [deg.] C. A method according to any one of the preceding claims, characterized in that the amount of the coating on the surface is not less than 0.001 g / m <2> in the dried state. <EMI ID = 165.1> previous dications, characterized in that the pH adjusting agent is selected from the group formed by sulfuric acid, phosphoric acid, nitric acid, molybdic acid, lactic acid, acid glycolic, thioglycolic acid, phytic acid and their acid salts. 8. Process for the polymerization of a vinyl monomer or of a mixture of vinyl monomers, the polymerization being carried out in a polymerization reactor having a surface in contact with said monomer or said mixture of monomers, characterized in that (1) said surface is coated, before proceeding with the polymerization, with an aqueous coating liquid containing at least one compound (a) selected from the group consisting of alkali metal salts and ammonium salts of water-soluble anionic dyes in the sulfonic acid form or in the carboxylic acid form and at least one compound ( b) chosen from the group formed by the water-soluble cationic dyes having at least one pair of conjugated double bonds and at least one nitrogen atom per molecule and having a pH adjusted by the use of a pH adjusting agent to a value not greater than 7 and (2) the surface thus coated is dried. 9. A method according to claim 8, characterized in that the aqueous coating liquid also contains a monovalent alcohol having 3 to 5 carbon atoms per molecule, in an amount of 1 to 20% by weight based on the above coating liquid. 10. A method according to any one of claims 8 and 9, characterized in that the concentration of the alkali metal salt or of the ammonium salt water soluble anionic dye in the liquid <EMI ID = 166.1> 11. A method according to any one of claims 8 to 10, characterized in that the pH value of the aqueous coating liquid is equal to or less. at 5. 12. A method according to any one of claims 8 to 11, characterized in that the hot drying step is carried out at a temperature of 40 to 100 [deg.] C. 13. A method according to any one of claims 8 to 12, characterized in that the amount of the coating on the surface is not less than <EMI ID = 167.1> 14. A method according to any one of claims 8 to 13, characterized in that the ratio of compound (b) to compound (a) varies from 100: 0.1 to 100: 1000 by weight. 15. A method according to any one of claims 8 to 14, characterized in that the <EMI ID = 168.1> formed by phytic acid and its acid addition salts. 16. A process for the polymerization of a vinyl monomer or of a mixture of vinyl monomers, the polymerization being carried out in a polymerization reactor having a surface in contact with said monomer or said mixture of monomers, characterized in that (1) there is coats said surface, before polymerize an aqueous coating liquid containing at least one compound (a) selected from the group formed by alkali metal salts and ammonium salts of water-soluble anionic dyes in the sulfonic acid form or in the carboxylic acid form and at least one selected compound (c) from the group consisting of silicic acid, silicates and water soluble salts of metals other than alkali metals and having a pH adjusted by means of a pH adjusting agent to a value <EMI ID = 169.1> coated. 17. The method of claim 16, characterized in that the aqueous coating liquid also contains a monovalent alcohol having from 3 to 5 carbon atoms per molecule, in an amount. <EMI ID = 170.1> above. 18. Process according to any one of <EMI ID = 171.1> The centration of the alkali metal salt or the ammonium salt of the water-soluble anionic dye in the aqueous coating liquid ranges from 0.01 to 5% by weight. 19. A method according to any one of claims 16 to 18, characterized in that the pH value of the aqueous coating liquid is equal to or less than 5. 20. A method according to any one of claims 16 to 19, characterized in that one carries out the hot drying step, at a temperature of 40 to 100 [deg.] C. <EMI ID = 172.1> claims 16 to 20, characterized in that the amount of the coating on the surface is not <EMI ID = 173.1> 22. Method according to any one of the <EMI ID = 174.1> between compound (b) and compound (a) varies from 100: 0.1 to 100: 1000 by weight. 23. A method according to any one of claims 16 to 22, characterized in that the pH adjusting agent is selected from the group consisting of phytic acid and its acid addition salts.