DE2224938A1 - PROCESS FOR THE PRODUCTION OF POLYVINYL POLYMERISATES - Google Patents

Description

DR. BERG DIPL.-ING. STAPF

PATENTANWÄLTE 8 MÜNCHEN 8O, MAUERKIRCHERSTR. 45

Dr. Berg Dipl.-Ing. Stapf, 8 Munich 80, MauerkircherstraQe 45 * Your sign Your letter Our sign date "i "'S JkJaI

Attorney file 22 374
Be / Soh

Ethyl Corporation Richmond / USA

"Process for the production of τοη polyvinyl

polymers "

This invention relates to an improved efficient process for the production of polyvinyl bromide "

It is well known that polyvinyl bromide using free Hadikal-initiated polymerization of vinyl bromide can be produced. However, this reaction runs

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β (0811) 48 82 72 <98 82 72) 48 70 43. <98 70 43) 48 33 10 (98 33 10> Telegrams: BERGSTAPFPATENT MOnchen TELEX 05 24 560 BERG d Banki Bayerische Vereinsbank Munich 453100 Postal check: Munich 653

if conventional processes are used to initiate the polymerization, it decreases slowly and technically inadequate low conversions of monomer to polymer are obtained. Attempts have been made to achieve faster polymerization of vinyl bromide and high yields by using relatively large amounts of free radical initiators and by means of long-lasting reactions. However, the polymers obtained in such cases were colored, from which their poor thermal stability can be seen. Üo reports for example Ulinska and Mankowski, Ötudia üoc. at. Torun, beet. B, volume 2, iio. 2 (1960) that the 6-hour polymerization emulsion of vinyl bromide at 50 ⁰ O using 1.5 ^ potassium persulfate as a free radical initiator gives only a 69% yield of yellow polymer. Furthermore, it is reported that one obtains a 88> üige polymer yield with the same initiator concentration after a reaction time of 24 hours and that the product obtained was dark brown after drying ₀ There was always the possibility essentially colorless polymers in very low yields (from 5 to 14 #) can be obtained in short reaction times by solution polymerization, but attempts to improve the yields by increasing the peak time have led to brown products.

The aim of the invention is a method for the production of Polyvinyl bromide with improved thermal stability

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and without color change when drying.

For the purposes of the invention, vinyl bromide monomer is aqueous Emulsion under the influence of free radical polymerization catalysts formed in situ polymerized. A special object of the process is that one controls the formation of free radicals so that the rate is sufficiently high to be practically feasible To maintain the reaction speed and thus a reasonable overall reaction time, but is low enough about the formation of a partially degraded olympusate with low working and thermal stability to be avoided, Furthermore, the supply of free radicals generated at the necessary rate becomes sufficient Maintained for a long time in order to obtain a high conversion of the monomer into the polymer.

It has been found that the appropriate rate or ratio of radical formation is best having regard to a typical pair of free radical generating agents, such as a reducing agent and a peroxide agent, namely sodium sulfite and ammonium persulfate, can be defined. To define the speed the formation of free radicals is included in this description, based on the specified reactants a reaction temperature of 50 ° 0 and in the presence of a Standard amount of a catalytic metal salt, namely

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Copper (II) sulfate, in a concentration of about 7 expressed.

The preferred working range is then obtained by continuously using an aqueous sodium sulfite solution at a rate of at least about 4 1/2 χ 10 "equivalent weights or equivalents of sodium sulfite per hour per 100 parts by weight of monomer to an aqueous emulsion of vinyl bromide at about 50 ° C, which is about 7 ppm copper (II) sulfate (based on the weight of the monomer) and at least about 3 x 10 equivalents of ammonium persulfate contains per 100 parts by weight of monomer, adds. The upper limit of this preferred range is the speed which can be achieved by continuously adding the sodium sulfite solution at a no higher rate as 6 1/2 χ 10 "" ^ equivalents per hour per 100 parts Monomer receives, provided the emulsion does not exceed 5 1/2 χ Contains equivalents of ammonium persulfate per 100 parts by weight of monomer and the other conditions remain the same.

It should be noted that the particular free radical generating agents identified above, namely sodium sulfite and ammonium persulfate, by others functioning similarly Materials can be replaced provided the same dosing criteria are followed. the Determination of the respective quantities for a specific

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This can be done by a specialist. The equivalent weight of a compound is the molecular weight of the compound divided by the change in oxidation number per Molecule in a special oxidation-reduction process that is considered here. For example, is subject to in the reaction between ammonium persulfate and sodium sulfite according to the following reaction sequence

(NR.) _O b _o 0 _a "+ 2 Na ₀ SO _x - * 2 Na ₀ SO ,,. + 2 (NR ₁ ) SO,

Sulfur a change in oxidation number from +7 in persulfate to +6 in sulfate. Because two sulfur atoms subject to this "change in a unit, the equivalent weight of Ammoniurapersulfat is half the molecular weight _o The equivalent weight of sodium sulfite corresponding to the molecular weight. If, therefore, one equivalent of ammonium persulfate and one equivalent of sodium sulfite were used to initiate the polymerization and one now wishes to use a different initiator system, it would only be necessary to use one equivalent of the other peroxide compound and one equivalent of the other reducing agent. The equivalent weights of the other peroxide compound and the reducing agent, and thus the actual weights for each material intended for use, should be determined according to the particular oxidation-reduction reaction which they undergo when they interact with one another.

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Instead of the sodium sulfite mentioned above, numerous other suitable reducing agents are used, for example sulfurous acid, ammonium, sodium or Potassium sulfite, ammonium, sodium or potassium bisulfite, Ammonium, sodium or potassium metabisulphite, ammonium, sodium or potassium hydrosulphite, aldehyde sulphoxylates such as Ammonium, potassium or sodium formaldehyde sulfoxylate, Ammonium, sodium or potassium thiosulfate and the like. Particularly preferred reducing agents are the sulfites, bisulfites, metabisulfites, aldehyde sulfoxylates and thiosulfates of ammonia, sodium and potassium.

Instead of the ammonium persulfate mentioned above, another peroxide compound can be provided. To suitable Peroxide compounds include ammonium, potassium and sodium sulfates, Ammonium, potassium and sodium perborates, hydrogen peroxide, Sodium, potassium or ammonium salts of peracids such as peracetic acid, perbenzoic acid, succinic acid peroxide or tert-butyl peroxymaleic acid. Particularly preferred Peroxide compounds are ammonium persulfate, and Potassium persulfate and hydrogen peroxide.

It is to be pointed out that the desired formation of the free radical development of the olymization catalyst can be achieved by adding a peroxidizing agent to the emulsion system in the appropriate amount to .reducing compounds was previously supplied »

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Thus , for example, ammonium persulfate could be used at an equivalent rate of about 4 1/2 to 6 1/2 (χ 10 "" ^) per hour per 100 parts of monomer, preceded by sodium sulfite in an equivalent amount of about 3 to 3 1/2 (χ 10) per 100 parts of vinyl bromide monomer content.

While the preferred rates of radical formation in view of the continuous addition rates or addition ratios of the reducing agent to the peroxide compound or the peroxide compound to the reducing agent were defined and although the continuous addition one to carry out of the process of the present invention is a desirable embodiment, it is also possible, however, to use the polymers the invention by discontinuous addition of either the sedative or the peroxide compound, however you want, as long as the rate of hadikal formation is as given above Area is held. However, it is not possible to the polymers of this invention by adding the Total amount of the two free radical initiating compounds at the start of the polymerization process, such as this has been described according to the prior art, because it cannot be achieved by means of such a method it is possible to achieve the desirable radical formation

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to maintain a sufficient length of time to obtain high yields in reasonable reaction times. The reaction time is not critical provided that the rate of free radical formation is within the preferred range, but it is necessary to carry out the polymerization at a rate sufficient to obtain high yields in reasonable reaction times. While an upper limit with regard to the rate of radical formation is therefore set by the desire or the need to produce an essentially colorless polymer with improved thermal stability, the lower limit is set by the need to avoid technically impracticable long reaction times.

The emulsion of vinyl bromide is prepared by mixing water and vinyl bromide in a ratio of water blends to vinyl bromide from about 0.5 to about 5. A preferred range is about 0.7 to about 3.0. An emulsifier is also added to the mixture of vinyl bromide and water added to promote emulsification.

The emulsifier may suitably be used in an amount of from about 0.5 to about 12 weight percent based on weight Vinyl bromide monomer can be used. A particularly preferred range is from about 1 to about 8 based on the weight of vinyl chloride monomer.

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The emulsifier can be anionic, cationic or nonionic in nature, or mixtures of these types of emulsifiers can be used. Examples of anionic emulsifiers are, without restricting the invention, for example sodium dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate and sodium bis (tridecyl) sulfosuccinate, sodium, potassium or ammonium salts of saturated or unsaturated aliphatic carboxylic acids such as lauric, palmitic, oleic, or kicinoleic acids, sodium salts of sulphated oils such as castor oil, tall oil, diesel oil or alkyl oleates, sodium salts of alkylarylsulphonic acids such as straight or branched dodecylbenzenesulphonic acid or isopropylnaphthalenesulphonic acid, sodium, potassium or ammonium salts of disproportionate, or sodium, rosin acids, or sodium salts - or ammonium salts of sulfated unsaturated acids such as oleic, tall oil acids or Hicinol-, sodium, potassium or ammonium niumalkylsulfate ^s, obtained by sulfation and subsequent neutralization of linear or branched aliphatic XL · ρ -Op ₁ - en hol Aiko receives, such as sodium lauryl sulfate, Sodium tridecyl sulfate or sodium octadecyl sulfate, sodium, potassium or ammonium salts of sulfonic acids, which are obtained by sulfonation and subsequent neutralization of linear or branched ΰ ^ 2 ~ 02ΐ, - ^ 1ν ^ - ^Ά -01θϊ ± ηβη , sodium salts of sulfonated esters, which from Polyols and unsaturated aliphatic carboxylic acids are produced, such as glyceryl trioleate and the like, ßei-

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Examples of cationic emulsifiers are alkyltrimethylammonium halides such as cetyltrimethylammonium chloride or Dodecyltrimethylammonium chloride, acylamidoalkyldimethyl (2-hydroxyethyl) ammonium salts such as ötearamidopropyldimethyl-ß-hydroxyethyammonium nitrate; bis (2-hydroxyethyl) octadecylamine oxide, alkyldimethylbenzylammonium chlorides such as Lauryl dimethyl benzyl ammonium chloride and the like. Examples of non-ionic emulsifiers are alkylphenoxy- polyoxyethylene ethanol, fatty acid ethylene oxide condensates, oxyethylated phenols, lanolin, glycerol esters, athoxylated Lanolin, wool wax alcohols, oorbitan esters, polyoxyethylene sorbitol oleate, Polyoxyethylene fat glycerides, polyoxyethylene palmitate, Glycerides of fats and oils, fatty alcohol derivatives, Fatty acid esters, ethyoxylated fatty alcohols, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, Oleic acid diethanolamide and the like.

As previously stated, it is an accurate concentration a soluble or partially soluble metal salt in the .Reaktion supplied, which serves to the formation of the to accelerate free radicals, which are necessary for the polymerization of the yinyl bromide. As a comparison to define the catalyst system required, as discussed earlier, approximately 7 ppm Copper (II) sulfate is used. However, it can also do this other metal salts can be used, including salts of chromium, manganese, iron, cobalt, nickel or silver. .

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Typical compounds that can be used for this purpose are, for example, ghrom-III-chloride, Manganese chloride, manganese oxalate, iron-III-nitrate, iron-II-sulfide, Iron-III-chloride, cobalt-III-chloride, cobalt-II-cyanide, Kickel acetate, hickel formate, copper (II) chloride, Copper (II) salicylate, copper (II) sulfide, silver carbonate and silver thiosulfate. The usual concentration range such components range from 0.05 to 100 ppm. In certain cases, small amounts of metal ions can be used present in the mixture or through contact of the reaction mixture with the metal of the reaction vessel system to be available.

Other materials useful for the polymerization emulsion may be present in the reaction system. For example, a few drops of antifoam agent can be provided. Antifoam agents include, for example, silicones (for example dimethylsiloxane), tallow oil derivatives, fatty esters, polyglycols, etc. Buffer salt systems can be used, for example approximately 0.05 to 5% (based on the monomer weight) KaH ₂ PO ₄ .H ₂ O with $ 0.05 to $ 5 Na ₀

The temperature which is used to carry out the polymerization is not particularly critical and temperatures from 30 to 60 ^° C. can usually be used.

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The following examples illustrate the invention.

example 1

In a 1 liter stainless steel reaction vessel are placed: 0.780 g of ammonium persulfate, 240 ml of water, 4 drops of Anti-foam 60 (a silicone antifoam agent manufactured by General Electric Corp.), 12.0 g of sodium dodecylbenzenesulfonate, 0.50 g of sodium dihydrogen phosphate monohydrate , 0.51 S disodium hydrogen phosphate and 0.108 ml of a 2 # solution of copper sulfate pentahydrate in water. The autoclave is closed, pressure checked and evacuated and flushed three times with nitrogen. Approximately 200 g of vinyl bromide are supplied to the sucked out autoclave, whereafter the autoclave is immersed in a bath which is maintained at 50 ⁰ G and the agitator is set. When the temperature of the reaction mixture has reached 50 ⁰ C, a solution with the content of 0.936 g (0.468 $, based on the monomer) of sodium sulfite and 30 ml of water was added to the autoclave at a rate of 5 ml P ^ c- hour. This corresponds to the rate of radical formation that can be achieved by adding sodium sulfite in a gel. Speed of 6.2 10 equivalents per hour per 100 parts by weight of monomer to an emulsion of vinyl bromide that 3 * 4 χ 10 "" * equivalents ($ 0.39) ammonium persulfate per 100 parts by weight of monomer and 7 parts of copper -II-sulfate contains ppm weight monomer. The autoclave was removed from the bath and drained after 6 hours. That

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The reaction product was a white latex that was approximately 157> 5 g Polyvinyl bromide corresponding to a 78.8% conversion. After the latex has been in dried in an air-circulating oven, the polymer was dry in the color fairly white, from which it can be seen that the polymer has an improved thermal stability has compared to the previously described emulsion polyvinyl bromido

Example II
(Comparative example)

The reaction would be carried out as in Example 1 except that 1200 g of ammonium persulfate and 30 ml of sodium sulfite solution containing 1.44 g ($ 0.72 based on the monomer) sodium sulfite are used. This corresponds to the rate of radical formation obtained by adding sodium sulfite at a rate of 9.5 x 10 "equivalents per hour per 100 parts by weight of monomer to an emulsion of vinyl bromide which is 5» 3 x 10 "** Equivalents ($ 0.60) ammonium persulfate per 100 parts by weight of monomer and 7 ppm of copper sulfate, based on the weight of the monomer, contains »A purple colored latex containing 178.5 g of polyvinyl bromide, corresponding to a yield of $ 89.2, is received. After being dried overnight at 55 ⁰ G in a convection air, the dry polymer was dark brown. From the previous

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It is clear that the strongly discolored latex obtained in this example, which is a polymer with lower thermal properties Stability was the result of the reaction being carried out too quickly, creating an excessively high speed the formation of hadikal was caused. This explains the need for the response in such a To be carried out in a manner that the rate of radical formation can be carefully controlled.

Example 3

The reaction was carried out as in Example 1 except that 225 g of vinyl bromide were used. This corresponds to a rate of radical formation that one by adding sodium sulfite ($ 0.42 based on monomer) at a rate of 5j5 x 10 equivalents per hour per 100 parts by weight of monomer to form an emulsion obtained from vinyl bromide, the 3> 0 χ 10 ^ equivalents ($ 0.34-7 »based on the monomer) Ammonium persulfate per 100 parts by weight of monomer and 7 parts of copper H sulfate ppm Weight contains monomer. The reaction product is a white latex containing 163.9 g of polyvinyl bromide which corresponds to a conversion of 72.8 #. After getting it over Has dried overnight at 55 ° C in an air circulation oven, was the dry PolymerisaVweißlich.

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Example 4
(Comparative example)

In a stainless steel autoclave (capacity 45 liters) was added 18.3 liters of water, 91.4 g of ammonium persulfate ($ 0.62 based on the monomer), 914.0 g sodium dodecylbenzenesulfonate, 38.1 g sodium dihydrogen phosphate monohydrate, 38.8 g disodium hydrogen phosphate, 8.2 ml. 2 # copper sulphate solution and approx. 25 g antifoam agent 60 introduced. The autoclave was closed, the stirrer and run at 200 rpm, stirring the mixture for approximately 15 minutes. The kettle was checked for pressure and then pumped down to a pressure of 76 torr and flushed three times with nitrogen before 15 »2 kg (33» 5 lh) vinyl bromide, inhibited with methyl ether of hydroquinone, were admitted. The autoclave was then heated to 50 0 and a solution containing 54.8 g of sodium sulfite ($ 0.36, based on the monomer) in 1 1 solution, was added continuously as follows:

During the first hour - 270 ml of the solution. During the second hour - 322 ml of the solution During the third hour - 348 ml of the solution During the fourth hour - 373 ml of the solution. During the fifth hour - 385 ml of the solution During the last 24 minutes - 142 ml of the solution.

This corresponds to the speed of radical formation, which can be made by adding sodium sulfite to an emulsion

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of vinyl bromide containing 5-3x10 equivalents of ammonium persulfate per 100 parts by weight of monomer at a rate of 9-8-10 equivalents per 100 parts by weight of monomer per hour. The autoclave was cooled and after 5-4 hours drained. The product was a purple colored latex. 100.0 g of this latex were dried for eighteen months at 55 ° in an air-circulating oven. The dry product, 40.90 g, corresponding to a conversion of 91.4 ^, was brown; ⁿ _rel = 1.132.

Example 5

The reaction was carried out as in Example 4, except that 59 ₅ 4 g of araraonium persulfate (0.40> δ, based on the monomer) were fed to the autoclave, the sodium sulfite solution 35.6 S sodium sulfite (0.23 / O ₅ based on the monomer ) contained in 1 1 solution and the addition of the sulfite solution was carried out as follows:

during the first hour - 263 ml of solution during the second hour - 232 ml of solution during the third hour - 225 ml of solution, during the fourth hour - 266 ml of solution during the fifth hour - 249 ml of solution during the sixth hour - 243 ml of solution during the seventh hour - 247 ml of solution during the eighth hour - 257 ml of solution

This corresponds to a speed of radical images

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manure, which can be obtained by adding sodium sulfate to a

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An emulsion of vinyl bromide containing 3 ^ x 10 ^y equivalents of ammonium persulfate per 100 parts by weight of monomer, at a rate of 4.6 χ 10 ~ equivalents per part by weight of monomer per hour. The autoclave was cooled and emptied after 8.0 hours. The product was a white latex. 100.0 g of this latex was dried overnight at 55 ° G in a forced air oven. The dry product, polyvinyl bromide, 38.79 gj corresponding to a conversion of 86.4 #, was off-white.

Example 6

The reaction was carried out as in Example 1 except that 0.900 g of ammonium persulfate was used and the 30 ml of sodium sulfite solution contained 1.08 g ($ 0.54, based on the monomer) of sodium sulfate. This corresponds to a rate of radical formation that is obtained by adding sodium sulfite at a rate of 7.2 χ 10 equivalents per hour per 100 parts by weight of monomer to an emulsion of vinyl bromide that is 3.9 x 10 ^ equivalents ($ 0.45 , based on the monomer) ammonium persulfab per 100 parts by weight of monomer and 7th parts of copper (II) sulfate ppm by weight; Contains monomer. An off-white latex containing 172.5 grams of polyvinyl bromide was obtained, which corresponds to a conversion of $ 86.2. After drying overnight at yj 0 L in an air circulation zone, the dried po ly-

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merisat light brown.

From the examples it can be seen that if a polymerization process is carried out according to the principles described here, one is a superior polyvinyl bromide can produce.

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Claims (1)

Claim: Process for emulsion polymerization of monomeric vinyl bromide with the formation of relatively stable polyvinyl bromide with good Parbe, characterized in that the polymerization is induced by free radicals which are formed by reacting a reducing agent with a peroxidizing agent at the same rate as when adding about 4 V2 10 "^ to 6 ^x / 2 χ 10 Eat riumsulf it equivalent per hour per 100 parts of monomer to about 3 x 10 to 5 ¹ 12 χ 10 ^J aminonium persulfate equivalent per 100 parts of monomer at a temperature of about 50 ⁰ C and in the presence of copper (II) sulfate j]] of the emulsion in proportions of about 7 ppm, based on the monomer. ORJGfNAL 909 881/0599; \:>,. .