DE1720343A1 - Process for the preparation of aqueous dispersions of copolymers of vinyl esters of organic acids and isobutene - Google Patents

Description

PATENT Attorneys «ι η <j λ q / O

DR.-ING. BY KREISLER DR.-ING. SCHÖNWALD DR.-ING. TH. MEYER DR. FUES

COLOGNE 1, DEICHMANNHAUS

Cologne, January 15, 1968 Kl / Ax / Hz

BP OHEMICALS (U.K.) LIMITES,

Britannic Hottae, Moor Lane, London, E.0.2 (England).

Process for the_production_ _> of .__ aqueous_dispersions

and isobutene

The invention relates to a method for producing film-forming aqueous dispersions of copolymers of vinyl esters of organic acids and isobutene, which are so produced dispersions and the films and sheets formed from the dispersions. -

According to the invention, aqueous dispersions of copolymers of vinyl esters of organic acids and Iaobutene with a low content of residual monomers after a Process prepared in which a good conversion of the total monomer input to polymer in an industrially acceptable Response times can be achieved?

The process according to the invention for the preparation of aqueous dispersions of copolymers of vinyl esters of organic Acids and isobutene is characterized by the fact that a vinyl ester of a saturated monocarboxylic acid is used and isobutene in an aqueous dispersion in the presence of a free radical forming catalyst and a surface active one Copolymerized by means of and / or a protective skin colloid, up to a proportion of the monomers in the range of up to 95% by weight of the total monomer input in the polymer

209 813/1323

is converted, and then the unpolymerized isobutene is removed from the dispersion and the polymerization of the remaining vinyl ester continues.

After the removal of the iaobutene which has not polymerized Additional catalyst is preferably added from the system.

The acid component of the vinyl ester of saturated chlorocarboxylic acid most conveniently contains 1 to 12 carbon atoms. This component may be eleitet from an aliphatic or aromatic acid from _ö. Examples of such esters are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl esters of tertiary aliphatic carboxylic acids, for example the product with the trade name "Veova 911" (manufacturer Shell Chemical Company), and vinyl benzoate. The invention is particularly directed to the vinyl esters of acetic acid or substituted acetic acid, for example vinyl esters of trimethyl acetic acid. Mixtures of vinyl esters of saturated monocarboxylic acids are just as suitable as mixtures of vinyl esters with other copolymerizable unsaturated monomers, for example acrylic acid, methacrylic acid, fumaric acid or itaconic acid or esters of these acids or vinyl halides. These other monomers contain polymerizable unsaturated CC bonds, for example ethylenic double bonds. During the polymerization, they can be present in amounts which contain copolymers with up to 50% by weight of the monomer residues. Small amounts of monomers which contain more than one polymerizable unsaturated CC bond, for example ethylene glycol diacrylate, butylene glycol dimethyl ylate, vinyl acrylate, triallyl cyanurate or divinyl adipate, can be present. The polymer formed preferably contains no more than 45% by weight of residues of copolymerizable monomers other than the vinyl ester and isobutene. The proportions of the monomers present in the polymerization must be adjusted accordingly.

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Catalysts which form free radicals are generally known. Any of this type of catalyst can be used for the purposes of the invention. The catalyst can consist of a single compound or contain several compounds which are effective in combination as a system and which can be soluble or soluble in oil. Examples include the organic and inorganic peroxides, lersulphates and 7 eroxycarbonates, e.g. ammonium persulphate, and the dialkyl percarbonates, e.g. diisopropyl peroxydicarbonate, azo compounds, e.g. azobisisobutyronitrile, and redox systeines.

Typical activators in Itedox systems are the alkali • Cjte, -dithionates, -thiosulfates and -aldehyde sulfoxylates, secondary and tertiary amines or transition metal salts in their inferior form. Some examples of redox systems are ivalium persulphate / sodium metpbisulphite, cumene hydroperoxide / complex-bound divalent iron, anunonium perbulphate / sodium foreialdehyde sulphoxylate, ITatriuinchlorate / HatrJumsulfit.

Suitable surface-active agents are any of the known ion-active or non-ionogenic agents, which can be used alone or as a mixture. Suitable ion-active agents are, for example, the anion-active agents, e.g. the alkali salts of alkyl acrylsulphonic acids (e.g. sodium dodecyldiphenyl ether disulphonate), alkali salts of long-chain fatty acid sulphates (e.g. l ^ atrium lauryl sulphate) and , e.g. -Condensates and IJonoesters von Lang.ketti _ü en Pettsäuren nit a.Lehrvverti ^ en alcohols (s _c B. Sorbitnonooleate). Semicircles of anionic and non-ionic substances are particularly effective.

The use of Sehut ^ colloids in v, ^r ässri _ü en freiradika ■ ** '·. '. ic "polymerization system is well known".

•. ■ ■

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Any protective colloids can be used for the purposes of the invention used, for example polyvinyl alcohols and water-soluble cellulose derivatives (e.g. gelulose ethers, such as methyl or hydroxyethyl cellulose)

The polymerization can be carried out by the reactants i & Waseer to form an emulsion or suspension are dispersed »The ratio of the The weight of water to the total weight of the monomers used is most expediently in the range from 10: 1 to 1: 2, preferably at about 1: 1. The weight ratio of the vinyl ester the isobutene used is expediently in the range from 99s1 to 75s25 »preferably in the range of 90:10 to 80:20. The free radical copolymerization catalyst should be present in an effective amount which triggers the PolymörTelftiön. Appropriately lies the proportion of catalyst in the range from 0.1 to 2.0 wt .- ^, preferably in the range of £ 0.5 Ms 1.5 wt .- ^, based on the weight of the monomer unit. The proportion of dispersion stabilizers, d.k. is a surfactant or the surfactants and optionally used protective hummingbird is preferably 0.5 to 6.0 ^ 5, based on the weight of the monomers »

The process can be carried out in batches, semi-continuously or be carried out continuously. With semi-continuous You can carry out the vinyl ester or isobutene or add both. 'In the preferred embodiment of the In the semicontinuous process, all of the isobutene is given and the vinyl ester is metered in. The catalyst can also be metered in or added in portions. In most technical applications, the proportion of the monomer that is present before the isobutene is removed to form polymer is converted, expediently in the range from 75 to 90 wt .- ^, based on the total weight of the monomer.

813/1323 _o where ^ ^{AL m3? EGTED}

134

..The .precise'print, "at & m & ± ®

is not crucially important ^ ei 'must Jeäoefe. gen _{2 in} order to keep the isobutene in the liquid phase © at least up to the isobutene iso'-butene *. This can be achieved _$ by -preventing. " that ■ Isobutendärapfe escape from the reactor. In general, overprints "up to 14 kg / cm"..'.'-

The unpolymerized® isobutene can expediently be satfersfe by reducing the pressure _s under which the dispersioB. _ΰ is lowered to the pressure _f at which the verbleibena © isobutene escape from the Flüsßigphase kaöHg- by, for example, the dispersion freely Eat- ^outwardly: biases.

Isobutene has a strong inhibitory effect on the polymerization. G-enügend isobutene should be removed to this effect largely repealed and allow the formation γοη Gopolymerdispersionen that low levels of free ^r Vinylester have.

TJm the loss of vinyl esters when the isobutene is blown off To keep the latex temperature as low as possible from the system, the temperature of the latex should be below the boiling point of the vinyl ester Normal pressure are maintained. It is also possible to separate the vinyl ester from the vented gas by condensation. In this phase, further polymerization can be carried out catalyst or activator can be added to the polymerization of the vinyl ester to complete. The reaction is preferred continued until the free monomer content is below about 0.5% by weight based on the weight of the latex, lies.

The polymerization temperature is not critically important. tig. Any temperature at which a sufficiently rapid reaction takes place is suitable. This temperature is expediently in the range of. 40 to 100 ⁰ C. The reaction time

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depends on. such factors "such as the catalyst used, and syatem äem proportion of isobutene in the liquid phase from.

The Pjj value of a dispereion can be regulated and normally are kept in the range from 3.5 to 7.5 in order to largely switch off the hydrolysis of the vinyl ester. A suitable one Buffering agents such as potassium or sodium bicarbonate can be added for this purpose.

The polymerization is expediently carried out with the exclusion of oxygen.

Marketable filrabildende aqueous dispersions of copolymer of s Yinylestern of organic acids and isobutene should not exceed 2 $> _t is preferably less than 1 wt .- # free residual Monomerea included. The invention provides a process for the preparation of such dispersions in technically acceptable reaction times. For example, in many cases response times of the order of 8 hours are possible

Stable aqueous dispersions of copolymers of vinyl ester and isobutene with a solids content of more than than $ 40 can by setting the proportion accordingly of the yinyl ester and isobutene to the existing Water and the polymerization conditions

j will be.

example 1

j In a 4 »5 1 stainless steel reactor after \ flushing with nitrogen, an aqueous phase the following composition was gegebem

', / asaer 700 g

Potassium bicarbomite 4.5 g

Anion active detergent
(Trade name "Abex 18-S") 60 g solids)

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-. 7 -

Nonionic surfactant (Trade name "Empilan IP 30") 27 g.

After further rinsing, 238 ml of vinyl acetate and 6 g of ammonite tetrasulfate in 120 ml of water were added. The reactor was closed, whereupon 128 g of isobutene were blown in with nitrogen from a storage container. The reaction was stirred and heated to 8O ° 0, where a pressure of 6 _S 79 kg / cm was created. A further 593 ml of vinyl acetate were pressed into the reactor over the course of 5 hours. During this time the 2JA fifl * UOK 3 "22 kg / cm ^2" After the pressing, the total solids content showed the latex sales of 82.6% to · The approach we de cooled to 5O ⁰ C, was called off after which the isobutene, until the pressure in the reactor had dropped to normal pressure. The latex was then kept at 80 ^{0 0 for a} further 2 hours. The solid content was 51> 0% by weight, the vinyl acetate content was 0.37 $. The final turnover was 96 »

For comparison, the polymerisation described above was: tion repeated with the difference that not chilled and = was not blown off · The solids content of the latex was 49 | 9 $ »the monomer content 3.3P» · the conversion was

94.2 #. ■.

Example 2

A 4.5 1 stainless steel reactor was filled with nitrogen rinsed, after which an aqueous phase of the following composition was introduced:

Water 700 ml

Potassium bicarbonate 4.5 g

Anion-active detergent "Abex 18-S" 60 g

Nonionic surfactant »Empilan NP 30" 27 g

After further rinsing, 166 ml of vinyl acetate and 120 ml Water, the 6.0 g ammonium persulfate, 1.5 g benzoyl peroxide and containing 1.5 g of sodium metabisulfite was added.

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The reactor was closed, whereupon 128 g of isobutene iiit. Nitrogen were injected from a storage container. The reaction was heated at 5O ⁰ C with a pressure of 4 | 2 kg / cm was established. 664 ml of vinyl acetate were pressed into the reactor over the course of 5 hours. The temperature of the reactor contents was kept at 50 0 for the first 2.5 hours and then increased ^{to 80 0 G for the remainder of the polymerization.} After pressing, the total solids had a conversion of $ 87.0. The isobutene was blown off until the pressure in the reactor had fallen to normal pressure. The reactor contents were held for an additional hour at 80 ⁰ C., The solids content was 50.5 wt .- $, the content of vinyl acetate monomer 0.5 / '° and the sales

Example 3

A 4.5 liter reactor was purged with nitrogen, whereupon an aqueous phase of the following composition has been introduced:

Water 700 g

Potassium bicarbonate 4.5 g

Anion-active detergent "Abex

18-S ¹¹ 60 g

ilichtionogenic surfactant
Medium "Empilan! IP 30" 27 g

After further rinsing, 166 ml of vinyl acetate, 2.7 g of butylene glycol dinethacrylut and 6.0 g of ammonium persulfate in 120 ml of water are added. The reactor was closed, whereupon 128 g of isobutene were injected with nitrogen from a storage container. The reaction was heated at 8O ⁰ C, during which a pressure of 7.7 kg / cm was established. Then 664 ml of vinyl acetate were pumped into the reactor over the course of 5 hours. During this time the pressure fell

to 2.94 kg / cm. After the introduction, the showed Total solids content of the latex a conversion of 79.4 ^.

BATH ORIGINAL

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It was heated for another hour, after which the Isobutene was blown off until the pressure in the reactor had fallen to normal pressure. After adding 1.0 g of ammonium persulfate was heated for a further hour. The solids content was 53, Q ^ and the content of free monomeric vinyl acetate 0.67 ^. The conversion was 95 »7 $ β

Example 4 "

A 4> 5 1 stainless steel reactor was filled with nitrogen rinsed, whereupon an aqueous phase of the following composition together with 323 g of vinyl acetate in a mixture was introduced with 17 g of 2-ethylhexyl acrylate:

YiTasser 75Og

Anion-active detergent "Abex 18-S" 29 g. (3Qfo pesticides)

Non-ionic surfactant

Medium »Binpilan IP 30» 22 g

Gum arabic (trade name
^r ".Qum .Arabic AAA§ 10 g

After adding 3 g of potassium persulfate as a solution in 75% water which contained 0.1 g of an ethylenediaminetetraacetic acid disodium salt ("Sequestrol 2Na"), the reactor was closed. 150 g of isobutene were pressed into the reactor from a heated storage container. The reactor contents were stirred and heated to 8O ⁰ O, resulting in a pressure of 5 »95 atm * The hired! Eemparatur of Heaktorinhalts was maintained for 1 hour at 80 ⁰ O, whereupon 484.5 g of vinyl acetate in lisohung 25>5'g 2-ethylhexyl aorylate were pumped into the reactor within 4 hours. During this time, equal aliquots lalle solution a "Lb containing 5» 6 g of potassium persulfate and 8 g Natriumdiearbonat g in UP · Water, added in intervals of 15 minutes. After the addition of this solution, the reactor contents 1 further hour at 80 ⁰ was O. After this time, the pressure in the reactor fell to 4.48 atmospheres

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- ίο -

Total latex solids indicated sales of $ 83.7. The reactor contents were cooled to 60 ⁰ C and the isobutene was blown bis.der pressure had dropped in the reactor to atmospheric pressure. After introduction of a solution of 1.4 g of potassium persulfate and 2 g Hatriumbicarbonat in 27 g of water, the reactor contents for a further 2 hours at 80 ⁰ C was maintained. The final contaminant content of the latex was $ 48.1, the free monomer content was $ 0.59 vinyl acetate and $ 0.14 acrylate, and the final sales were $ 92.1.

For comparison, the same polymerization was repeated with the difference that there was no cooling and no venting. The solids content of the latex was 47-8 $ and the monomer content was 3 * 71 $ vinyl acetate and 0.12 $ acrylate. Sales were $ 91.5.

Example 5

A 4 »5 liter stainless steel reactor was purged with nitrogen, followed by an aqueous phase of the following Composition was introduced together with 750 g of vinyl acetate and a solution of 4 »68 g of ammonium persulfate and 3» 34 g of sodium bicarbonate in 155 g of water?

Water 750 g

Anion-active detergent "Abex 18-S ¹¹ 29 g ($ 30! Solids)

Nonionic «surfactant Medium »Bmpilan NP 30» 20 g

Polyvinyl alcohol (trade name "öelvatol 20/90") 10 g

The reactor was closed, whereupon 100 g of vinyl chloride were blown in with nitrogen from a storage container together with 150 g of isobutene from a heated storage container. The contents of the reactor were stirred and ^{heated to 8O 0} O, a pressure of 6.79 atmospheres being established. The reactor was held at this temperature for 4 hours. After this time, a solution containing 1.51 g of ammonium perma-

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sulfate and 1.08 g of sodium bicarbonate in 50 g of water, printed into the reactor within 15 minutes. The temperature of the reactor content was held for an additional 2 hours at 8O ⁰ C. The pressure in the reactor dropped to 5.95 atmospheres and the solids content of the latex indicated a conversion of $ 85.1.

The reactor contents were cooled ^{to 60 0 G.} The isobutene and vinyl chloride were blown off until the pressure in the reactor had reached normal pressure. A solution of 0.81 g of ammonium persulfate and 0.58 g of sodium bicarbonate in 16.5 g of water. was then pumped into the reactor. The reactor contents were then held for a further 2 hours at 80 ⁰ Q. The final solids content of the latex was 49-2 $ and the free monomer content was 0.62ji, expressed as vinyl acetate. The final conversion was 95

The same polymerization was repeated for comparison only with the difference that not cooled and blown off became. The solids content of the latex was 47.4 / the conomer content 4.25 £, calculated as vinyl acetate * The conversion was 91 »6 / ··

Example 6

A 4.5 1 stainless steel reactor was filled with nitrogen rinsed, whereupon an aqueous phase of the following composition susaianen with 260 g of vinyl acetate in a mixture was introduced with 80 g of vinyl propionate:

Water 750 g

Anion-active detergent with the trade name "Satinol" 5g

ITichtionogenic surface-active

Medium "Renex 6QC» 15 g

Hydroxyethyl cellulose colloid.

"Natrosol 250L". 20 g

After adding 3 g of potassium persulfate as a solution in 75 g Water containing 0.1 g of the disodium salt of ethylenediamine ~ tetraacetic acid ("Seuuestrol 2Na") was used

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Closed reactor. 200 g of isobutene were pressed into the reactor from a heated storage container, whereupon the reactor contents were stirred and ^{heated to 80 °} C., a pressure of 7 atmospheres being established. The temperature of the reactor contents was held for 1 hour at 8O ⁰ C, were pressed whereupon 390 g of vinyl acetate in admixture with 120 g of vinyl propionate within 4 hours into the reactor. "Jährend this time, equal aliquots of a solution of 5.6 g of potassium persulfate and 8 g of anhydrous sodium carbonate in 108 g V / ater in Abstünden 15 Llinuten added * iTach taken place addition the reactor contents were held for an additional hour at 80 ⁰ C. After During this time, the pressure in the reactor had fallen to 5-6 atmospheres, and the solids content of the latex indicated a conversion of 68.1 ^. The reactor contents were ^{cooled to 55 °} C., whereupon isobutene was blown off until the pressure in the reactor reached normal pressure had fallen. Kine solution containing 1.4 g of potassium persulfate and 2 g of anhydrous Hatriumcarbonat in 27 g '/ ater contained the final solid was pumped into the reactor, after which the reactor contents for another 2 hours was held at 8O ⁰ C. content TUs latex was 49.2%, the free ionomer content was 1.75%, calculated as vinyl acetate, and the final conversion was 91.4%.

For comparison, the same polymerization was repeated with the only difference that it was not cooled and that it was not cooled was blown off ο The solids content of the latex was 46.6fj, the uromer content 5.9, *, expressed as vinyl acetate, and the Ui.isatz 86.4 ^ ·

BAD QRJGiMA!

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Claims (8)

Claims 1) Process for the preparation of aqueous dispersions of copolymers of vinyl esters of organic acids and isobutene, characterized in that a vinyl ester of a saturated Monocarboxylic acid and isobutene in an aqueous dispersion in the presence of a catalyst which forms free radicals and a surfactant and / or a protective colloid ^ polymerized until a proportion of Monomers in the range from 65 to 95 wt .- # of the total monomer input is polymerized, and then the unpolymerized Isobutene is removed from the dispersion and the polymerization of the remaining vinyl ester continues. 2) Method according to claim 1, characterized in that one in addition to the vinyl ester of saturated monoarboxylic acid and isobutene, one or more other copolymerizable monomers are used. 3) Method according to claim 1 or 2, characterized in that that additional catalyst is added after the unpolymerized isobutene has been removed. 4) Process according to claims 1 to 3 * characterized in that that the entire isobutene is added at the beginning and the vinyl ester is metered in, 5) Process according to Claims 1 to 4, characterized in that the unpolymerized isobutene is removed by the dispersion is allowed to relax to the outside unhindered. 6) Process according to Claims 1 to 5, characterized in that the vinyl ester of saturated monocarboxylic acids is vinyl acetate begins. 209813/1323 7) Aqueous dispersions of copolymers of vinyl esters of organic Acids and isobutene, obtainable according to claims 1 to 6. 8) Films, produced from aqueous dispersions, according to claim 7 209813/1323