Additive, composition comprising it and use thereof.

ADDITIVE, COMPOSITION THAT COMEKENDS HIMSELF AND ITS USE

The present invention relates to an additive, compositions comprising the additive and its uses. More specifically, the invention relates to antifouling additives for use in processes for the polymerization of aqueous suspensions. The invention has particular application for example in the polymerization of vinyl chloride optionally in the presence of other monomers.

The polymerization of aqueous suspensions of monomers such as vinyl chloride (sometimes referred to as VCM) to produce polymers is well known. A problem is that part of the polymer material produced covers the reactor vessel and the internal parts. This results in several disadvantages that include reducing heat transfer through the reactor walls and wasting monomer. In addition, although the polymer is generally firmly attached to the reactor walls, the particles can be dislodged, affecting the quality of the resulting polymer.

It is known to provide anti-fouling compositions. These materials are applied to the reactor walls and resist the formation of a polymer coating on the reactor walls. Examples of these materials include partially hydrolyzed polyvinyl acetates (sometimes referred to hereinafter as

PVA). A problem with these materials is that a re-coating is generally required after each batch of polymerization.

Attempts have been made to provide anti-fouling compositions that do not require coating after each of the polymerization batches. Examples of such materials are described for example in GB 1 439 339, EP 0 052 421, JP 54 107 991 and WO 9708210.

GB 1 439 339 describes an antifouling composition that is obtained by reaction of phenol with formaldehyde. According to JP 54 107 991 this material is not very effective since excessive crosslinking takes place ·

EP 0 052 421 describes anti-fouling compositions obtained by reacting formaldehyde with an effective 1-naphthol. As used in EP 0 052 421, effective naphthol is a naphthol that is capable of copolymerizing with formaldehyde in positions 2 and 4. As such, positions 2 and 4 are not substituted and position 3 is either unsubstituted or It is not substituted with a group of strong electron uptake such as sulfonic acid.

JP 54 107 991 describes anti-fouling compositions from phenol / formaldehyde condensation products of preliminary stage. According to EP document

0 052 421, although better than the anti-fouling material described in GB 1 439 339, this material produces variable results.

WO 97 08 210 describes anti-fouling compositions based on naphthenic molecules substituted with 10 sulfur compounds in at least one position on the aromatic structure.

A problem with these materials normally when

<td></td><td>used in combination with PVA is that</td><td>do not</td><td>S Θ</td><td>stick</td>

<td></td><td>intensely to the walls of the. reactor.</td><td>This</td><td>gives</td><td>place to</td>

<td> 15</td><td>various problems. First, it must</td><td colspan="2">Apply</td><td>material</td>

excessive that is subsequently wasted. Secondly, productivity is reduced because the material that drains from the reactor walls should be collected and removed. Third, the material that does not remain on the reactor walls is mixed with the mixture of reactants and can modify the properties of the resulting polymer.

Therefore, the invention aims to seek improved anti-fouling compositions for use in the polymerization of polymerizable monomers such as VCM and in particular to prepare anti-fouling compositions more adherent to the reactor walls. Surprisingly, it has been found that acrylate polymers such as co (polymers) of poly (acrylate ester) improve the retention properties of the antifouling compositions, especially those comprising condensation products of a phenol olof naphthol and formaldehyde or a 1naphthol having a sulfur-containing substituent. Even more surprisingly, it has been found that, contrary to the considerations of many prior disclosures, PVA may result in less inlay anti-fouling compositions to the reactor walls.

In addition to the binder, an additional component is present that may be selected from

i) a crosslinked product formed by reaction of formaldehyde and a phenol, for example as described in GB 1439339 ii) a phenol / formaldehyde condensate for example as described in document CA1181899 iii) condensation products of 1-naphthol and formaldehyde for example as described in EP0052421 and iv ) Sulfur-substituted naphthenic molecules, for example, as described in W009708210, anti-fouling compositions can also be used alone by components.

i) a

Each set of embedded material is described in more detail:

one. Condensation Product of Formaldehyde and Phenol

Crosslinked

The condensation product is an insoluble crosslinked polymeric material containing polar groups formed from a reaction mixture having an aldehyde, preferably formaldehyde, as one of its components. The other component or at least one of the other components (if there were more than one) of the reaction mixture should have more than two sites of reactivity with it. in order to form a polymer crosslinked with the aldehyde.

By insoluble ”it is understood that the polymeric material does not dissolve or react with the aqueous medium (either acidic, neutral or alkaline) or with the organic medium used in the polymerization.

Suitable crosslinked polymeric materials include materials obtained by condensation of monomeric phenols such as phenol and parahydroxybenzoic acid with an aldehyde and materials obtained by crosslinking monomeric or polymeric materials such as melamine, diaminodiphenyl ether, urea and polyethyleneimine with a aldehyde. It is preferable that the aldehyde used is formaldehyde since crosslinked products are easily obtained with this material. It should be understood that many of the polar groupings of said crosslinked materials may not have taken part in the crosslinking reaction.

In the case of the basic coating material (ie alkaline) it is preferable that the polymerization medium is maintained at a pH greater than 4 by means of the use (when necessary) of Pampons or alkaline substances. Suitable alkaline substances include sodium hydroxides, potassium io, calcium and ammonium hydroxides, carbonates and bicarbonates, and buffers that include mixtures of ortho phosphate monosodium phosphate and disodium (Na2HPO4 and NaH2PO4).

Of course, it should be understood that the pH of the reaction medium may, in itself, remain above 4, in which case the addition of an alkaline buffer or substance may not be necessary.

A preferred coating is obtained by reacting 1.2 parts of polyethylene imine with 5 gels of formaldehyde and heating at 80 ° C for 10 minutes.

Another preferred material is obtained by putting in

<img file="MX368271B_D0001.tif" />

Contact 3 parts of polyethylene imine with 20 parts of formaldehyde at room temperature.

Preparation Example

138 g of p-hydroxybenzoic acid were heated with 100 ml of water and 100 g of 30% aqueous formaldehyde and 15 ml of conc. HCI. at 98-100 ° C for 2 hours. The initial white solid (p-hydroxybenzoic acid) dissolved and after about 1 hour, a white solid precipitated.

After cooling to approximately 60 ° C, aqueous NaOH was added continuously until all the white precipitate had dissolved and the pH of the medium was 9.6-10. This solution was called A.

138 g of p-hydroxybenzoic acid, 100 g of 30% aqueous formaldehyde were mixed and a 40% aqueous NaOH solution was added until the initial solid dissolved and the pü was 9.6-10. This solution was called B.

Solutions A and B were mixed and refluxed for 20 minutes. A thick red syrup formed which, after acidification with dilute HCI, provided a white precipitate. This was filtered, and washed with water. It was partially dried at room temperature by aspiration of air through it using a vacuum pump.

An additional condensation product was prepared by contacting a solution of 3% by weight of diaminophenyl ether in ethyl methyl ketone with aqueous formaldehyde and heating to 70 ° C for 3 minutes.

two. Phenol / formaldehyde condensate

The term "phenol" in the context of phenol / formaldehyde condensate means monohydric phenols such as phenol, cresol and ethylphenol; poly (water alcohols) such as resorcinol and hydroquinone; bisphenols such as bisphenol A; and its nuclear replacement products. The term "aldehyde" means organic compounds that have at least one CHO group such as formaldehyde, acetaldenide and furfural. In a preferred embodiment, the condensation product consists of a phenol and formaldehyde (or paraformaldehyde). The condensate can be prepared by conventional methods. Preferably, the condensation product of phenol and aldehyde should not be, in the form of macromolecules formed by curing but in the form of a primary condensation product of the first stage. In the first stage of the condensation of phenol-formaldehyde, a novolac resin is produced in the presence of a basic catalyst and a resol resin in the presence of a basic catalyst as the main product. Preferably, the condensation product is a resol that can be obtained in the form of an aqueous solution. It can be prepared by adding formaldehyde to an excess of the phenol in the presence of caustic soda, caustic potash, ammonia or amines.

When the condensation product is a novolac, the product that can be used is in the form of an alkaline aqueous solution or a solution in such an organic solvent. as methane1.

A modifier can be added. The condensation product is modified by heating after mixing with the modifier. For alkylphenol.es of resolute product or dihydric phenols such as resorcinol, hydroquinone and bisphenol Ά can be used as the modifier. For novolac-type products, aldehydes and hexamethylenetetramine can be used.

If the phenol-formaldehyde condensation product is of the resol type, it should preferably be soluble in a caustic soda solution of 10% by weight. Thus, these two liquids should be mixed to form a liquid that is homogeneous in any mixing proportions. The average molecular weight of the condensation product that is soluble in a caustic soda solution of 10% by weight is within a fairly wide range. However, it is preferable to employ a product in which the molecules have 1 to 20 benzene nuclei, and more desirably 5 to 10 benzene nuclei per molecule.

Preparation Example

94 g of phenol (1 mol), 100 g of 48-weight formalin (1.6 mol of formaldehyde) and 2 g of caustic soda (0.05 mol) were introduced into a three-mouth flask that had a reflux condenser and subsequently heated to 85 ° C for 20 minutes with stirring. The mixture was maintained at 85 ° C for 3.5 hours during the reaction and subsequently concentrated to 75% by weight of the component in solids under reduced pressure at said temperature.

The viscosity of the resol obtained according to ASTM D 2196 was measured using a spindle No. 4 at 60 rpm and 25 ° C. The value of 2,500 centipoises was obtained.

4 g of resorcinol were added to 50 g of the resol and subsequently the mixture was subjected to a temperature rise to 95 ° C for 30 minutes with stirring. The mixture was maintained at 95 ° C for 10 minutes and the condensation product was diluted with a caustic soda solution of 2% by weight up to 5% by weight concentration of solid components.

Preparation Example

1128 g of phenol (12 mol), 1203 g of formalin of 48% by weight (19.2 mol ·) and 60 g of caustic soda solution of 40% by weight (0.6 mol) were introduced into a Three-mouth flask that had a reflux condenser and subsequently underwent a temperature rise to ° C for 20 minutes with stirring. The reaction mixture was maintained for one hour at 85 ° C, and showed a viscosity of 10 centipoise at a temperature of 80 ° C, according to the above-mentioned measurement method, using a spindle No. 60 rpm

This condensation product had a concentration of 74% by weight of solid component, and was named as G2.

Preparation Example

1000 g of condensation product G2 was introduced into a three-mouth flask having a reflux condenser and 100 g of resorcinol was added. The mixture was subjected to a temperature rise to 85 ° C for 20 minutes with

<td>15 agitation</td><td>and the r</td><td>eaction</td><td>of condensation</td><td>continued to</td><td> 8 5</td><td>° C.</td>

<td>During is</td><td>proc</td><td>that is</td><td>they got four</td><td>or samples</td><td>from</td><td>50 g</td>

<td>each,</td><td>that you:</td><td>they had a</td><td>viscosity of 5</td><td> &gt;00, 1.000,</td><td> 2.0</td><td>00 and</td>

5,000 centipoises respectively, measured by the above-mentioned measurement method, using spindles No.

3 and No. 4 at 60 rpm, at 80 ° C. Each contained 76% by weight solids.

Preparation Example

100 g of each G2 condensation product were introduced separately into two three-mouth flasks that had a reflux condenser, then 10 g of hydroquinone was added to one of the flasks while adding 10 g of bisphenol A separately to the other. Each mixture was subjected to a temperature rise to 85 ° C for 20 minutes and the condensation reaction continued at 85 ° C until the viscosity reached 1,000 centipoise at 80 ° C by means of the above-mentioned method, using a spindle No. 3rd 60 rpm. Each contained 76% by weight solids.

Preparation Example

<td> 10</td><td>I know</td><td>poured</td><td> 18,8</td><td>kg ds</td><td>s phenol</td><td> (200</td><td>mol</td><td> ·),</td><td>i kg</td><td>from</td>

<td></td><td>metacresc</td><td>x'l (50 mol)</td><td colspan="2">and 25.0 kg</td><td colspan="2">of formalin</td><td colspan="2">of 48%</td><td colspan="2">in weigh</td>

<td></td><td>(4 00 mol:</td><td>! and 1.25 kg</td><td colspan="2">of dissolution</td><td>: s ion</td><td colspan="2">bear caust</td><td>loa of</td><td>a 4 0</td><td>or Ό</td>

<td></td><td>in weigh</td><td>(12.5 mol</td><td>) in</td><td>the</td><td>inside</td><td>from</td><td>a</td><td>recipi</td><td>entity</td><td>from</td>

<td></td><td>reaction</td><td>that he had</td><td>a c</td><td>: onden</td><td>sador of</td><td>ref]</td><td>Luj o</td><td>and</td><td>I wear</td><td>to</td>

<td> 15</td><td>out the</td><td>reaction to</td><td colspan="2">a tempe:</td><td>catura ch</td><td> ?. 85</td><td>OQ</td><td colspan="2">Remained</td><td>the</td>

Condensation reaction at a temperature of 80 ° C until the viscosity based on the above-mentioned measurement method employs a spindle No. 3 at 60 rpm reached 500 centipoise. The product contained 75% by weight solids.

Preparation Example

<td>Were introduced</td><td> 94</td><td>g</td><td>from</td><td>phenol (1 mol),</td><td>100g</td><td>from</td>

<td>48% formalin (</td><td colspan="2">; n weight</td><td> (1,6</td><td>mole of formaldehyde</td><td>Ldo) and 5</td><td> , 05</td>

<td>g (0.05 mol) of triet</td><td colspan="2">.ilamina</td><td>in</td><td>a flask of three</td><td>mouths</td><td>what</td>

<td>I had a condenser</td><td>from</td><td>ref li</td><td>1 jo</td><td>and subsequently</td><td>it was heated</td><td>noticed</td>

up to a temperature of 85 ° C. The mixture was maintained at a temperature of 85 ° C until the viscosity reached 10 centipoise through the above-mentioned measurement method, using a spindle No. 1 to 60 rpm

3. Condensation Product of Naftol and Formaldehyde

Preferably, the condensation reaction between an effective 1-naphthol and formaldehyde is carried out in a catalyst-based reaction, that is, by means of condensation of effective naphthol and formaldehyde in the presence of a base. Condensation can also (although less preferably

<td>from the</td><td>point of view</td><td colspan="2">practical) to take away</td><td colspan="2">Finish in</td><td>a</td>

<td>reaction</td><td>catalyzed by</td><td>acid,</td><td>that is to say,</td><td>by</td><td>medium</td><td>from</td>

<td>condensation</td><td>Ion in presence!</td><td>of a</td><td>acid. In</td><td>both of them</td><td>CCLSOS</td><td>the</td>

Condensation is carried out appropriately in an aqueous medium (which is alkaline or acidic as the case may be). The structure of the condensates is not known, but it is thought that they are not resoles or novolacs as these terms are applied in a conventional manner to the phenol / formaldehyde condensates prepared respectively by means of a base-catalyzed reaction or a reaction catalyzed by acid. Thus, the spectral analysis by means of nuclear magnetic resonance spectroscopy and infrared. condensate prepared from 1-naphthol and formaldehyde itself under aqueous alkaline conditions, although complex and unable to provide a definitive molecular structure, has indicated that the condensate does not contain free methylol groups as expected if the product were a conventional stage resol preliminary - although the presence of several types of methylene bonds is observed (presumably linked to the naphthalene z and 4 nuclear positions, since methylol groups 2 and 4 are observed preliminary in condensation, although these have disappeared in the final product). In addition, the determination of molecular weight 0 by boilingometry indicates that only relatively small molecules containing up to three or four units from 1-naphthol are present. Additionally, it appears that 1-naphthol and formaldehyde react together in substantially equimolar amounts to form the condensate © (see below). Consequently, the absence of methylol groups, the result of the molecular weight determination, and the apparently equimolar reaction leads to the conclusion that the product in this case is probably a mixture of trimers: 0 cyclic and tetramers in which the units coming of 1naftol are linked by means of bridge methylene groups in nuclear positions 2 and 4. Also, the achievement of an effective product. Very similar using an acid-catalyzed condensation (thought to be the same or very

<img file="MX368271B_D0002.tif" />

similar to the product from the base-catalyzed reaction) further points out that these deposit suppressor products are quite different in terms of the structure of conventional phenol / formaldehyde condensates.

The aqueous alkaline solutions (when they can be prepared) of these condensates are highly colored, often dark blue, and it is thought that the dark coloration may be due to the presence of a small

<td>quantity of a product</td><td>from</td><td>oxidation</td><td>not harmful (from</td><td>the</td>

<td colspan="3">10 point of view of suppressing activity of</td><td>deposits).</td><td></td>

<td>Can be produced</td><td>the</td><td>substance</td><td>anti-fouling</td><td>in</td>

<td>first place preparing</td><td>a</td><td>dissolution</td><td>aqueous aj.ca.lina</td><td>of the</td>

effective condensate of 1-na.phthol / formaldehyde (if soluble in an aqueous alkali), which will normally be the direct or diluted solution from the catalyzed reaction based on an aqueous medium, to form the condensate (the . basic catalyst for example aqueous NaOH, aqueous KOH or aqueous NH4OH and separating the alkaline aqueous solution that is formed from condensation, if necessary, from any small amount of precipitate that sometimes tends to occur), which optionally It contains an added surfactant to promote the surface coverage capacity of the condensate, applying this alkaline solution to the internal surfaces of the reactor (for example, by

6 spray, paint or flood media) and allow the formation of a condensate coating. The application of the solution in this way will cause itself (i.e., without adding anything else, such as drying or rinsing - although these steps can be used if desired) the formation of a strongly adherent coating of the condensate on reactor surfaces; optionally, however, the solution applied to the reactor may also contain other useful substances, for example an added protective colloid, such as poly (hydrolyzed vinyl acetate), (incorporated for example by further dilution of the solution with an aqueous solution of the protective colloid) in order to further improve the adhesion of the coating.

When aqueous NaOH or KOH is used as the basic catalyst for base-catalyzed condensation, it is preferable to use 0.7 0 to 0.90 moles of NaOH or KOH per mole of effective 1-naphthol (although of course other propo ries can be used ).

When the condensation has been produced by a reaction catalyzed by an acid (the acid catalyst being, for example, aqueous HCI), an alkaline aqueous solution can be produced first by means of isolating the product, and subsequently by dissolving it.

<img file="MX368271B_D0003.tif" />

in an aqueous alkali such as a solution of aqueous NaOH or aqueous KOH.

When it is possible to do so, it is preferable that the antifouling product is applied to the internal surfaces of the reactor in the form of an alkaline aqueous solution, for example, dissolved in an aqueous alkali such as an aqueous solution of NaOH or KOH as mentioned above. . In fact, this is possible for most antifouling products that are normally soluble in aqueous alkali. However, when the coating product is insoluble in aqueous alkali, other means can be used to carry out the application of the coating product to the internal surfaces of the reactor; for example, the product can be applied as a solution in an organic solvent - although this is not recommended for operation

<td>routine</td><td>to scale</td><td>of plant</td><td>due to</td><td>dangers</td><td>from</td>

<td>security</td><td>that could</td><td>arise.</td><td></td><td></td><td></td>

<td>Should</td><td>be understood</td><td>when</td><td>'the</td><td>product</td><td>from</td>

shaped coating of a solution in aqueous alkali, the

<td>product</td><td>may</td><td>be at least partially</td><td>in</td><td>i shape</td><td>.Na</td>

<td>Salt.</td><td></td><td></td><td></td><td></td><td></td>

<td>By</td><td>a 1-</td><td>- Effective naphthol is understood as:</td><td>one _ Í1 j.</td><td> na 11. or 1 that</td><td>sa</td>

<td>condenses</td><td>with</td><td>formaldehyde to form</td><td>a</td><td>product-</td><td>from</td>

<td colspan="2">coating</td><td>that have an activity</td><td>from</td><td>suppression</td><td>from</td>

deposits, that is, a product that can be used to provide an effective deposit suppressor coating. Many 1-naphthols are condensed with formaldehyde to give rise to products that have deposit suppressor activity, although it has been found that not all 1-naphthols give rise to a product that has such activity. In general, an effective 1-naphthol is a 1-naphthol in which both nuclear positions 2 and 4 are not substituted and in which the nuclear position 3 is not substituted or has a substituent that is not strongly electron capture. As an example of a strongly electron-capturing group, mention may be made in particular -SO2OH. The numbering used herein with respect to the naphthalene nuclear positions is the one recommended as definitive according to the IUPAC rules, that is to say

<img file="MX368271B_D0004.tif" />

Preferably, the effective 1-naphthol is selected from those of formula

<img file="MX368271B_D0005.tif" />

<img file="MX368271B_D0006.tif" />

where n is 0 or 1; m is 0, 1, 2 or 3 (preferably Q, 1 or 2); R1 and R2, which may be the same or different, are selected from halogen (preferably Cl), hydrocarbyl (preferably alkyl of 1-5 carbon atoms), hydroxyl and hydrocarbyloxy (preferably alkoxy of 1-5 carbon atoms).

Examples of effective 1-naphthols include 1-naphthol, 1,3-dihydroxy-naphthalene, 1,5-dihydroxy-naphthalene and 1,7-hydroxynaphthalene.

Most of these condensation products (and in particular their alkaline aqueous solutions) can be stored for long periods without significant deterioration in efficacy, provided that precautions are taken to allow only limited access of oxygen; It is thought that unlimited oxygen access for a prolonged period allows the formation of oxidation products, which is normally manifested by substantial precipitation in the alkaline aqueous solution.

Of the effective 1-naphthols, 1-naphthol itself is the most preferred considering that it is cheap, its easy commercial availability and efficiency.

When condensation of 1-naphthol and formaldehyde occurs to form a coating product for use in the invention, it is thought that effective 1-naphthol and formaldehyde react together in substantially equimolar amounts in order to form the product, of so that any molar excess of 1-naphthol used remains unreacted and any molar excess of formaldehyde used reacts further with the product thereby lowering its yield.

Therefore, as regards training

<td>of the</td><td>product of</td><td colspan="2">condensation, it</td><td>believe that the proportion</td><td>from</td>

<td>the</td><td>quantities</td><td>from 1-naphthol</td><td colspan="2">effective and formaldehyde that</td><td>I know</td>

<td>mix</td><td>isn for</td><td>condensation</td><td>They are</td><td>particularly critical</td><td>already</td>

<td>what</td><td>it was considered</td><td>what do you have</td><td>place</td><td> the equimolar reaction.</td><td>Do not</td>

However, when a significant excess of one or other reactant is used, the coating product may, for the purposes of some polymerization recipes, be associated with an undesired amount of a contaminant (in which case a negative effect may be incurred ), and sometimes (depending on the condensation method used to prepare the coating product) it may be unprofitable or difficult to remove enough contaminant in order to avoid the negative effect. Thus, if one departs from the mixture of substantially equimolar amounts of effective 1-naphthol and formaldehyde for condensation, then the polymerization of vinyl chloride can sometimes be adversely affected, in particular if used a dialkyl peroxydicarbonate as a polymerization initiator. It is found that the polymerizations used by other initiators, for example lauroyl peroxide and azo compounds, are much less sensitive to the 1-naphthol / formaldehyde ratio. Generally speaking in such cases, a mixture for the condensation of effective 1-naphthol and formaldehyde in a molar ratio range of 1.1 / 1.0 to 1.1 / 1.2, in particular 1.05 / 1 , 0 to 1.0 / 1.1 is appropriate. The most preferred molar mixture ratio is substantially 1.0 / 1.0.

Preparation Example 1

The condensation products were prepared for use

<td>in the invention</td><td colspan="3">(at various scales) from</td><td>1-naphthol</td><td>Y</td>

<td>formaldehyde in</td><td>a reaction</td><td>catalyzed</td><td>per base</td><td>using</td><td>the</td>

<td>next recipe</td><td>generalized</td><td></td><td></td><td></td><td></td>

<td>Was introduced</td><td>eron 1-naphthol</td><td>(x or 1) and</td><td>NaOH (ent</td><td>re 0.7 x</td><td>Y</td>

<td>0.85 x mol, sir</td><td>badly 0.80</td><td>x mol) in</td><td>form of</td><td>I dissolved</td><td>ΟΓι</td>

1 molar aqueous in a reaction vessel and heated to 70 ° C. Formaldehyde (and mol, usually and equal to x) was added dropwise in the form of an aqueous solution of 36% by weight / volume with stirring, during which the rate of addition was controlled to allow only the temperature to rise from 70 ° C to 80 ° C. No external heating was required during the addition (exothermic). When all formaldehyde solution had been added, the contents of the reaction vessel were heated to reflux at 90 ^QC and refluxed for 30 minutes. The resulting alkaline solution of the coating product (blue) was used, which had an estimated product concentration of about 20% by weight / volume, either pure or diluted, in the invention. Either in pure or diluted form, alkaline solutions normally had a pH between 11-13.

Preparation Examples 2 and 3

Alkaline condensate solutions were prepared using substantially the recipe of Preparation Example 1, but the following substituted 1-naphthols were used instead of 1-naphthol itself:

Preparation Example 2: 1,3-dihydroxy-naphthalene; 0.025 mol scale; color of the dark red condensate solution.

3

Preparation Example 3: 1,7-dihydroxy-naphthalene;

0.25 mol scale; color of the dark green condensate solution.

Preparation Example 4

Initially, the same procedure was followed

Preparation Example 1 (on a 0.25 mol scale) but 1,5-dihydroxy-naphthalene was used instead of 1-naphthol itself. After a period of reflux a black precipitate formed. It was insoluble in an aqueous solution of NaOH but soluble in 10 organic solvents such as acetone.

Preparation Example 5

A coating product was generated for use in the preparation of. tank suppressor coating according to the invention, using an acid catalyzed reaction as shown. 1-Naphthol (36 g, 0.25 mol) was stirred in 180 ml of an aqueous solution of 1 molar HCI at 70 ° C. Formaldehyde (19.75 molar of an aqueous solution of 38% by weight / volume, 0.25 mol) was added and the stirred mixture was heated to reflux. After a few minutes, a conglomerate of deep brown / red color formed. This material was removed, the acid was washed, dried and crushed to a fine powder.

The powder was dissolved in 180 ml of an aqueous solution of 1 molar NaOH to give rise to a dark blue alkaline solution, very similar to 1.a. of Preparation Example 1, which

4 It had an estimated product concentration of 20% by weight / volume.

Preparation Example 6

The procedure of Preparation Example 1 was substantially followed, for the preparation of a coating product according to the invention (from 1-naphthol and formaldehyde) on a very large scale in which x - 1.11 x

10 &lt;3&gt; ey = 1.12 x 10 &lt;3&gt;.

Four. Naphthenic molecules substituted with sulfur

These materials include a naphthalene depending on the configuration;

<img file="MX368271B_D0007.tif" />

main chain substituted in at least one of positions 1 to 8 with a sulfur-containing radical characterized by the fact that it includes at least one sulfur atom (S) in at least one of these radicals.

In the · anti-fouling material there is one. substantial presence of sulfur and does not represent an impurity; therefore, the sulfur content must be greater than 0.25% by weight, preferably greater than 0.85%, the optimum percentage being 9.3%.

advantageously, the sulfur radical may be attached to oxygen (0). Equally advantageously, the radical is characterized by the presence of SOn where n can be 2 or 3. More preferably, the radical is characterized by the presence of the SOnNa group, where n can be 2 or 3.

Good activity is obtained by the addition to a naphthenic structure, sulphonic or sulphonic radicals that may be in the form of sodium salt such as -CH2SOnNa in the form of an individual radical at positions 2, 3 or 4 of the naphthenic structure or in the formulation - CH (SOnNa) - if you join two of these structures.

Preferred examples include

<img file="MX368271B_D0008.tif" />

where n can vary from 2 to 3.

<img file="MX368271B_D0009.tif" />

where n can vary from 2 to 3.

<img file="MX368271B_D0010.tif" />

CH₂SW_nNa where n can vary from 2 to 3.

0

<img file="MX368271B_D0011.tif" />

<img file="MX368271B_D0012.tif" />

<img file="MX368271B_D0013.tif" />

<img file="MX368271B_D0014.tif" />

where n can vary from 2 to 3.

<img file="MX368271B_D0015.tif" />

<img file="MX368271B_D0016.tif" />

OH where n can vary from 2 to 3.

<img file="MX368271B_D0017.tif" />

<img file="MX368271B_D0018.tif" />

OH where n can vary from 2 to 3.

Formation of the anti-fouling product:

These materials can be obtained by reacting a product having a naphthenic (aromatic) structure, such as, for example, the type of alfanaphthol, with sodium hydroxymethanesulphinate, CAS number 149-44-0 (603547-8 as dihydrate).

Sodium hydroxymethanesulphinate reacts with alfanaftol in a weight ratio of 1 to 1.5, in an aqueous solution of 10 to 50% and heating the solution to a temperature between 40 ° C and 100 ° C under a nitrogen atmosphere and in an alkaline environment (pH 11-13), forming the new product according to the present invention.

The solution of the product obtained in this way is clear and transparent but in the presence of oxygen it oxidizes slightly, adopting a bluish color. If contact with oxygen is interrupted, the product returns to its original clear transparent appearance.

The reason for the reversible color change may be due to the presence of sulfonic or sulfonic functionality:

<img file="MX368271B_D0019.tif" />

BLUE DISSOLUTION □ υ

The product can also be prepared by replacing sodium hydroxymethanesulphinate with sodium hydroxymethylsulphonate CAS No. 870-72-4. Alternatively, formaldehyde can also be reacted with sodium dithionite CAS No. 7775-14-6 and subsequently reacting the resulting product with a material containing a naphtanic main chain such as 1-naphthol.

Preparation Example

In an 8000 liter stainless steel reactor, equipped with an anchor agitator with a speed ranging from 20 to 40 rpm, 1200 kg of water, 180 kg of a 30% NaOH solution, 270 kg of 1- are introduced Naphthol under a vigorous flow of nitrogen.

The temperature is brought to 90 ° C and during the course of 2 hours 900 kg of a solution of sodium hydroxymethanesulphinate of 31.5% by weight / weight are added.

The solution is maintained at 90 ° C for 12 hours and subsequently 190 kg of a 30% NaOH solution are added, which results in a yellow and transparent solution.

The Binder

The binder is an acrylate polymer. It can be a homopolymer of acrylic acid or a copolymer or esters of acrylic acid. Styrene copolymers such as acrylic-styrene acid ester copolymers are preferred. Examples of acrylic-styrene acid ester copolymers are those of CAS number: 25767-47 such as: 2 ~ propenoic acid, butyl ester, polymer with ethenylbenzene, butyl ester of acrylic acid, polymer with styrene (8CI); benzene, ethenyl, polymer with butyl 2-propenoate (9CI); styrene, polymer with butyl acrylate (8CI); 290D; 95J-APR7446; AC 80; ACR 1555; Acronal 230D; Acronal 290D; Acronal 295D; Acronal 296D; Acronal 32QD; Acronal 4D; Acronal 725S; Acronal NX4748X; Acronal NX 4787; Acronal NX 4787X; Acronal PR 8689; Acronal S 305D; Acronal S 430P; Acronal S 559; Acronal S 702; Acronal S 728; Acronal S 760; Acronal S 790; Acronal V 271; AcryGen 4096D, AcryGen 4660; Acribase ZSR 1005; Akroplen 2; Almatex CPR 1000; Axilat DS 910; BB 01; BN 0107; Basoplast PR 8152; copolymer of Behenyl behenyl acrylate butyl styrene; butyl styrene acrylate copolymer; butyl styrene acrylate polymer; CPR 100; CPR 250; CPR 300; CS 40; CS 40 (low profile additive); Cevian A 46701; Craymul 2423; DL 420; DM 60; Dow Latex DL 420; Elotex BN 0107; Ercusol A 5250; FSR 051; FSR 053; Finndisp A 10; Finndisp A

<img file="MX368271B_D0020.tif" />

2

6000; Fulatex PN 3716G; GD 86B; Hexatec H 658-81; Himer SB 101; Himer SB 305; KD 350; KEY 1000; LL 990; Lenteks A 7; MK 9472; MP 1SM631G; Mowilith DM 60; Nikalite X; PA 805; PSB 2700; PSB 2931; Piccotoner 1221; Piccotoner 1278; Pliolite Ultra 100; Pliotone 2102; Pliotone PTR 7767; Poly (butyl styrene acrylate); Polyform IV; Primal EP 4030; RCI 2671; RCS 1-33; RP 70; RP 70 (acrylic polymer); Rhodopas DS 910; Rhodopas GS 125; Rhoplex EP 4030; Rhoximat DS 910; Robond 6114; S 559; S 790; SABU; SB 101; SC 001; SC 008; Sokrat 4924; Sokrat LX 75; styrene-butyl acrylate copolymer; styrene butyl acrylate polymer; n-butyl styrene acrylate copolymer; n-butyl styrene acrylate polymer; TL 3; TL 3 (polymer); TSF 2; TSF 2 (polymer); Texicryl 13-092; Texicryl TD 6213; Ucar 123; Ucar 481; Ucar DL 420G; Uramul SC 70; V 271; Vinnapas LL 512; Vinnapas LL 9400; Vinnapas LL 990; XPA 4165; n-butyl styrene acrylate copolymer; n-butyl styrene acrylate polymer. A particular suitable poly (acrylic ester) polymer is ACRO'NAL 290D which can be obtained from BASE. Other acrylates may include CAS Registration Number: 25686-45-7, 2-propenoic acid, polymer with 2-butyl propenoate and 2-propeneditrile acrylic acid, polymer with acrylonitrile and butyl acrylate (8CI); 2propenonitrile, polymer with butyl 2-propenoate and acid

2-propenoic (9CI); 2-propenoic acid, butyl ester, polymer with 2-propenonitrile and 2-propenoic acid (9C1); acrylic acid butyl ester, polymer with acrylic acid and acrylonitrile (8CI); acrylonitrile, polymer with acrylic acid and butyl acrylate (8CI); Acronal A 378; acrylic acid-acrylonitrile-butyl acrylate copolymer; acrylic acid-acrylonitrile-butyl acrylate polymer; acrylic acid-butyloacrylonitrile acrylate copolymer; BNK 206; BNK 246; BNK 306; BNK 406; butyl acrylonitrile acrylic acid copolymer; HTR 280DR; JSR-PAR 1H; Rikabond ET-L 924-1. Another suitable particular acrylate is Acronal A378. Other copolymers that may be appropriate are hydroxypropyl acrylic acid, hydroxyethyl ester of acrylic acid, acrylate copolymers of CAS number 25133-97-5, acrylate copolymers, / hydroxy ester acrylates, acrylate / VA copolymers of CAS 2560702-1. Mixtures of these materials can also be used. The (co) polymer of poly (acrylic ester) is preferably an aqueous base water dispersion and a (co) film forming polymer.

Normally, the weight ratio of condensation product or sulfur substituted 1-naphthol; to bind such as co (polymer) of poly (acrylate ester) is within the range of 3: 1 to 30: 1, for example 5: 1 to 15: 1 such

4 about 10: 1.

Conveniently, the composition of the invention can be prepared by homogenizing a mixture of anti-fouling composition in water with the binder, for example, a polyacrylate composition in water to give rise to a composition of the invention. Preferably, the composition of the invention has a pH within the range of 9 to 14, preferably 10 to 14, a viscosity within the range of 1-10 mPas, preferably 1 to 5 and the dry solids content is within the range from 1-20% by weight, preferably from 1 to 10.

The viscosity is measured by the following protocol:

one. Equipes

1.1. Haake 7L Plus viscometer equipped with a complete set of spindles.

1.2. Spindle assembly with low viscosity adapter from Haake.

1.3. Thermostatic bath capable of being controlled at 23 ° C ± 1.

1.4. Thermometer, precision 1 ° C.

1.5. Chronometer

1.6. Common Laboratory Glassware

5

2.1. Turn on the viscometer and set it to zero next

two. Procedure instruction shown on the screen.

2.2. Select the following conditions using the instrument control screen:

® Spindle No. LCP «Rotor speed: rpm 60 * Measurement mode: mPa-s

2.3. In a measuring cylinder, pour 20 ml of sample. Pour this sample into a low viscosity tube adapter. Place the tube inside a dish / bath. Allow the sample to reach a temperature of 23 ° C (± 1).

2.4. Place the spindle inside the sample (with caution to remove all air bubbles) and connect it to the viscometer. Use caution when connecting the spindle.

2.5 Check that the spindle is immersed to correct the depth and that the viscosimeter leveling the bubbles is centered: adjust if necessary.

2.6. Start the viscometer motor and the stopwatch at the same time. Wait 20 seconds and then read the viscosity value and the moment directly from the instrument screen.

3. Results

Haake viscosity is expressed in mPa * s. The value is directly available from the instrument screen.

Four. Determination accuracy ± 10%

The dry solids content is measured using the following protocol:

one. Equipment

1.1. Air circulation furnace

1.2. Analytical balance (accuracy: 1 mg).

1.3. Common Laboratory Glassware

two. Process

Each determination is carried out twice.

2.1. Weigh a clean and smooth glass container (approximately 10 cm in diameter) and write down the weight (Pl).

2.2. Weigh 1 to 2 g of sample into the container; Write down the weight (P2).

2.3. Place the container in the oven at 150 'C. Let the solvent evaporate for 30 minutes.

2.4. Remove the container from the oven and let it cool inside the desiccator for 15 minutes.

2. 5. Weigh the container with solid matter (P3).

3. Results

The result is expressed as a% solids content:

(P3-P1) / (P2-P1) x 100% solids in which (P3-P1) = amount of dry matter in g.

(P2-P1) = amount of sample in g.

Four. Accuracy gives the determination ± 1% (relative)

When the composition of the invention has properties within these ranges, the storage stability, handling and ease of application, such as to allow spraying of the antifouling agent on the reactor wall, are especially good.

Other materials may be present. For example, one or more of antioxidants, chelating agents, antifoaming agents, surface tension reducing agents, stabilizers and pH regulators. They are discussed in more detail below. It will be appreciated that none can be selected, or one or more of one material from each group can be selected in any compatible combination.

The. anti-fouling composition may be susceptible

<img file="MX368271B_D0021.tif" />

of oxidation Oxidation can impart an unwanted color to the resulting product. In order to reduce oxidation, the composition of the invention can be prepared and stored in low concentrations of molecular oxygen. For example, the composition can be prepared and stored in nitrogen. Oxidation can also be reduced by the addition of an antioxidant. Preferably, the amount of antioxidant is selected such that the final color of the product does not change when exposed to air for at least 10 30 minutes. However, the antioxidant is essential. In the absence of an antioxidant, the composition of the invention tends to be a blue milky emulsion and in the presence of an antioxidant it tends to be a green milky emulsion. Although the composition can be used in the absence of an antioxidant, it may be preferred to use the antioxidant and this may further reduce the appearance of dark colored coating material present in the white PVC polymer when the reactor coating is detached. The improved binding of the antifouling agent to the reactor wall, when used with the polyacrylic binder, also reduces the

<td>appearance of</td><td>detachment</td><td>of the</td><td>cover</td><td>anti-imitation</td>

<td>incrustation</td><td>from the</td><td>wall</td><td>of the</td><td>reactor and the</td>

<td>pollution</td><td>of the polymer of</td><td>Pvc</td><td>White</td><td>with any</td>

<td colspan="2">colored material, shrinking</td><td>of est</td><td>e mode</td><td>the need for</td>

9 antioxidant use

In some embodiments of the invention, chelating agents such as EDTA may be present and these may also serve to improve color stability.

In some embodiments of the invention, anti-foaming agents are present. Those skilled in the art will not have difficulty in selecting the appropriate antifoaming agents. An example of an appropriate antifoaming agent is ethanol. Experts will not have difficulty selecting other appropriate antifoaming agents.

In some embodiments of the invention stabilizers may be present. In addition to the materials that stabilize the composition against oxidation and color change, other stabilizers may be present. By way of non-limiting example, they may include effective storage stabilizers to reduce sedimentation or phase separation or freeze-freeze stabilizers. Examples of stabilizers include xanthan gums, nansa (ie alkylbenzenesulfonic acids and salts), alcohols such as methanol and isopropanol, and partially hydrolyzed EVA polyvinyl acetate. I know

<td>checked that</td><td>the formulations</td><td>prepared</td><td colspan="2">with stretch ©,</td>

<td>polymer with</td><td>butyl acrylate</td><td>) such as</td><td>Acronal</td><td>290D</td>

<td>provided</td><td>formulations</td><td>stable</td><td>front</td><td>to the</td>

Especially good storage along with anti-fouling materials.

This composition may be in a container form in which all the ingredients are mixed together or in the form of a multi-container, for example a two-container form in which the binder is in a first container and the other ingredients are in a second container. The shape of two packages is especially useful for compositions with limited storage stability.

Although PVA, whose term encompasses partially hydrolyzed polyvinyl acetate and polyvinyl acetate, has been used as an antifouling agent and can be used in the composition of the invention, it is not particularly preferred since surprisingly it has been proven to frequently reduce adhesion to reactor walls. In addition, the preparation of a PVA solution requires water heating to dissolve the PVA solid and increases manufacturing time and cost, while the polyacrylate (co) polymer can be used as it is.

When PVA is present, it usually comprises less than a% by weight of the composition, such as less than 5% by weight, for example less than 2% by weight, such as less than 1% by weight, such as less of about 0.5% by weight of PVA, for example 0.4% by weight, such as 0.3%

<img file="MX368271B_D0022.tif" />

by weight or 0.2% by weight. In some embodiments, the anti-fouling composition is substantially free of PVA. However, it is clearly understood that a low or no PVA content is preferred only in the anti-fouling composition. Generally, the polymerization of VCM takes place in the presence of PVA, as both primary and secondary suspending agent, but polymerization takes place. As explained below, the application of the composition of the invention to the surfaces takes place before carrying out the polymerization and before introducing the VCM and the concomitant PVA into the reactor.

In another aspect of the invention, an anti-fouling composition is provided which contains an acrylate polymer such as a copolymer of poly (loop acrylate ester) and al. minus one of (i) a crosslinked product formed by means of a formaldehyde reaction and a phenol, (ii) a phenol / formaldehyde condensate,

<td></td><td>(iii)</td><td colspan="2">a condensation product formed</td><td>through</td><td>from</td>

<td> 20</td><td>reaction of</td><td>1-na</td><td>ftol and formaldehyde, and</td><td></td><td></td>

<td></td><td>(iv)</td><td>a</td><td>molecule based product</td><td>s naphtheni</td><td>cas</td>

<td></td><td>replaced</td><td>with</td><td>sulfur compounds in at least</td><td>&gt; a position</td><td>ion</td>

of the aromatic structure but less than 2.0% by weight, for example less than a

0.1% by weight, such as less than 0.5% by weight of PVA. The composition may be in the form of a container in which all the ingredients are mixed, for example a polymer form of acrylate. Other ingredients selected second container.

The experts will have this method of producing the reeds or in two packages in which the ra in a first container and those between (i) and (iv) are in a: difficult handle to devise the position of the invention. For example, a solution or dispersion of at least one of (i) a crosslinked product formed by reacting formaldehyde and a phenol, (ii) a phenol / formaldehyde condensate, (iii) a condensation product formed by reaction of 1-naphthol and formaldehyde, and (iv) a product based on naphthenic molecules substituted with sulfur compounds is formed in at least one position of the aromatic structure and the (co) polymer of poly (acrylate ester) is added for example in the form of an aqueous solution at the same time that the pH of the mixture is maintained at at least pH 9. In preferred embodiments, an antioxidant is added to the solution before the addition of the poly (acrylate ester) co-polymer.

Other components such as anti-foaming agents can be added before or after the poly (acrylate ester) co-polymer.

In general, the poly (acrylate ester) polymer comprises 0.5-10% by weight of the anti-fouling composition.

The composition of the invention is applied to the reactor surfaces before the polymerization reaction. The precise form of application is not essential to the invention and could, for example, be by spraying, painting or immersion. In some embodiments of the invention, the application is carried out in the presence of steam. In some embodiments of the invention, the composition of the invention is subjected to a drying step but neither steam nor drying are essential. The amount of coating product to be used is not too critical, although the coating should not be too heavy (to avoid any possibility of staining the polymer) or too light so that the effective removal of deposits is not achieved; obviously, such limits will vary considerably according to several factors (for example, the tendency of the polymerization recipe to generate deposits to a greater or lesser extent - in particular in terms of the initiator used, and the quality, of the reactor surfaces) . Generally speaking, it is normal to apply a volume of coating product (for example by spraying, painting or immersion - usually by means of spraying in large-scale operations.) Of appropriate concentration, the volume being sufficient to coat uniformly the internal surfaces of the reactor; Of course, this will vary according to the size of the reactor. It has been found that it is convenient to apply a dispersion of low to moderate concentration to the reactor surfaces and apply it, in the smallest possible way, concomitantly with the acceptable surface coverage 10 and an effective coating weight appropriate to the recipe. of reactor / polymerization used; Of course, the effectiveness of the application equipment (usually a spraying apparatus) determines in some way the minimum amount of dispersion that can be used. (It will also be appreciated that the amount of coating product currently applied may be greater than that finally remaining on the reactor surfaces due to losses incurred, for example, drainage).

In other embodiments of the invention, the components are maintained separately. In a first step, a solution or suspension of the poly (acrylate ester) copolymer is applied to the reactor walls, for example, as described hereinbefore. This material is allowed to drain or air dry

Subsequently, a conventional anti-fouling composition can be applied, for example as described in WO97 08 210, GB 1

439 339, JP 54 107 991 or EP 0 052 421, for example as described hereinbefore and allowed to drain or dry.

The invention composition produces a strongly adherent anti-fouling coating on the treated surfaces. In many cases, the coating retains its anti-fouling properties during several VCM polymerization processes, such as 3 or more, 4 or more or 5 or more or 6 or more.

The composition of the invention can also be used for other functionalities such as anti-corrosion agent or as flame retardant. Normally, old reactors 15 may suffer a combination of polymer embedding and corrosion. Preferably, the composition of the invention comprises the combination of the condensate, an antioxidant, metal-chelating agent and acrylate. Without intending to be bound by this theory, it is thought that the condensate limits the rate of corrosion by neutralization of highly oxidizing radicals, the antioxidant can lower the redox state of the active metal centers, the chelating metalagent binds to the metals and makes them less active from the redox point of view and acrylate facilitates the formation of a protective film. In addition, the components have different chemical properties such as pH dependence (pKa) and water solubility. but, surprisingly, it has been found that by closely controlling the pH, the order of addition and reducing the amount of PVA (during the preparation of the antifouling agent) it is possible to form a stable solution.

Preferably, the composition of the invention is used to prevent corrosion or embedding in polymerization reactions but can also be used for a wide range of applications; for example, coatings to protect submerged surfaces of ships.

The polymerization process can be any manufacturing process for the polymerization of a vinyl monomer. Suitable processes may include processes for the manufacture of polychloroprene, polystyrene in suspension and acrylonitrile-butadiene-styrene (ABS), high impact polystyrene, expanded polystyrene (EPS), styrene-acrylonitrile copolymers, methyl-butadiene-styrene methacrylate, nitrile- butadiene rubber, polystyrene, polybutadiene, polyacrylonitrile, methyl polymethacrylate, vinyl acetate ie VAM copolymers and vinyl acetate copolymers, '' vinyl chloride. Processes for the manufacture of polychloroprene, polystyrene are preferred

7 in suspension and acrylonitrile-butadiene-styrene (ABS).

Preferably, the appropriate polymerization reaction conditions are those processes in which the reaction temperature is 40 to 200 ° C. More temperatures of 40 to 100 ° C are more preferred.

Appropriate processes are continuous or batch processes. Batch processes are preferred.

The polymerization pH range can be from pH 2 to

14. The preferred reaction pH is less than 8.

The polymerization is by means of any number of radical polymerization methods for example, block, solution, gel, suspension or emulsion polymerization. The suspension is preferred.

The vinyl monomer (s) may be

1.5 selected (s) from styrene ©, ethylene, propylene, butadiene, isoprene, vinyl acetate, vinyl chloride, vinyl pyrrolidone, vinyl caprolactam, tetrafluoroethylene, vinylidene chloride, vinyl sulfonic acid, acrylonitrile, methacrylonitrile, methyl ether and vinyl , vinyl cyclohexa.no, acrolein, vinyl butyl sulfide, ethyl vinyl ketone, vinyl pyridine, allyl acetate, allyl alcohol, allylamine, maleic acid, maleic anhydride.

Most preferably, the process for the polymerization of a polymerizable monomer is a process for the polymerization of a vinyl chloride. The term "polymerization of vinyl chloride" is the homopolymerization of vinyl chloride, the copolymerization of vinyl chloride with one or more comonomers copolymerizable therewith, or the polymerization of vinyl chloride in the presence of preformed polymers (optionally in the presence of agents of grafted) to form graft-type vinyl chloride polymers. Examples of comonomers (copolymerizable with vinyl chloride) include vinyl esters such as vinyl acetate, acrylic esters, such as methyl acrylate and butyl methacrylate, acrylic nitriles such as acrylonitrile and methacrylonitrile, unsaturated diesters such as maleate. diethyl, allyl esters, alpha-olefins such vinyl ethers and allyl compounds such as acetate such as ethylene and propylene, of styrene. Examples of preformed polymers for the formation of graft-type vinyl chloride polymers include acrylic ester polymers such as poly (n-butyl acrylate) methyl methacrylate homocopolymers, poly (2-ethylhexyl acrylate) and olefin copolymers / vinyl ester such as ethylene / vinyl acetate copolymers. It is preferable to apply the invention to the production of polymers containing at least 50 mol% and more particularly to the

9 minus 80 mol% of units from vinyl chloride.

The process of the invention is particularly useful when applied to the production of vinyl chloride / vinyl acetate copolymers containing 3-20% units of vinyl acetate, since, in any case, it is often extremely difficult · When known deposit suppressors are used to obtain a consistent deposit-free process for the preparation of said copolymers.

Any suitable suspending agent can be used for the aqueous suspension polymerization according to the invention. Referring to the polymerization of vinyl chloride, particularly preferred suspending agents are polyvinyl acetates of various degrees of hydrolysis and water soluble cellulosic esters. These suspending agents can be used together with secondary suspending agents if desired. The amount used can vary widely and is generally between 0.05 and 1.5% by weight, calculated on the vinyl chloride used.

Any suitable free radical polymerization initiator that is soluble in monomer can be used for aqueous suspension polymerization. Referring to the polymerization of vinyl chloride, particular examples include peroxy compounds such as di-tertiary butyl peroxide, lauroyl and acetyl cyclohexyl peroxide, sulfonyl peroxide, azo compounds such as azo-bis-isobutyronitrile and 2.2 ' -azo-bis-2,4-dimethylvaleronitrile. The monomer-soluble free radical polymerization initiators that are particularly suitable for use in the polymerization of vinyl chloride are dialkyl peroxydicarbonates (the term "alkyl" includes cycloalkyl) whose alkyl radicals contain up to 20 carbon atoms, such as diethyl peroxydicarbonate , diisopropyl peoxidicarbonate, Dicethyl peroxydicarbonate and tertiary bis (4-butylcyclohexyl) peroxydicarbonate and azo compound such as 2,2'-azo-bis-2,4-dimethylvaleronitrile and azo-bisisobutyronitrile. These initiators can be used in conventional amounts - in general terms from 0.01 to 1% by weight calculated on vinyl chloride.

The operating conditions for the polymerization according to the present invention may be those commonly used for the relevant polymerization. For example, generally, for the polymerization of vinyl chloride the polymerization temperature is within the range of 40 ° C to 80 ° C and the pressure is generally below 20 kg / cm 2.

As used herein

Vinyl monomer means a monomer that contains one or more polymerizable carbon-carbon double bonds.

Avoiding means both avoiding and inhibiting.

Embedding means unwanted polymerization such that the polymer precipitates on the reactor walls or is embedded in the process equipment, which leads to equipment shutdown and the cleaning requirement to remove polymeric fouling.

Embedding may also include other types of unwanted polymerization such as popcorn formation. In the production of a define, the accidental formation of a polymer called popcorn, of porous three-dimensional structure, takes place not infrequently on the apparatus, due to the polymerization of the olefin in the refining stage and recovery or in the recovery stage of the unchanged monomer after termination of the polymerization. This popcorn polymer appears both in the gas phase and in the liquid phase. The popcorn polymer is arranged to form seeds that can continue to spread. Therefore, the popcorn polymer adheres and stains the heat exchanger, the distillation tower and the pipes installed inside the system for the refining and recovery of the olefin produced and deteriorates the efficiency of the refining operation. Often clogs the device and its pipes. In an extreme case, the mechanical pressure generated during polymer propagation can deform and fracture the apparatus. The reason for the rapid propagation of the popcorn polymer is that, as the polymer grows, new radically active sites are formed within the polymer and the polymer achieves growth from the radically active sites that have just been formed.

In the following, particular embodiments of the invention are discussed by way of non-limiting reference to the Examples.

inmcffiDnoooeioniwiooaoaooooooooooo

a) 33.3 g of 20% by weight alkaline aqueous solution of solids content and pH of 13 antifouling agent (polycondensate) were prepared from the reaction of 1-naphthol and formaldehyde described in the Example of Previous preparation to give a dark green solution.

b) Poly (acrylic ester) copolymer was diluted (Acronal

90D of BASE supplied in the form of an aqueous dispersion of a solids content of 49-51% by weight) with water from a solution of 50% to 2% by weight and 33.3 solution of a solution was added. 2% by weight to 33.3 g of the mixture of step (a). The mixture formed a milky emulsion.

<td>c) dissolved</td><td>PVA powder</td><td>(from</td><td>hydrolysis of a 99</td><td>9- \ θ ¡</td>

<td>in water at 90 ° C</td><td>for 2 ho</td><td>flush</td><td>to provide</td><td>a</td>

<td>dissolution of a 2</td><td>, 7% by weight</td><td>Y</td><td colspan="2">allowed to cool until</td>

<td>room temperature</td><td>. Subsequently</td><td>tea,</td><td>di.sol.uc was added</td><td>ion</td>

<td>of PVA (33.3 g) at</td><td>mix of</td><td colspan="2">stage (b).</td><td></td>

<td>To minimize</td><td>the presence</td><td>from </td><td>oxygen, they took</td><td>the</td>

carry out the reactions under nitrogen.

Composition of Example 1:

Polycondensate 6.6% by weight, Acronal 290D 0.67% by weight, PVA 0.9% by weight.

Example 2

Example 1 was repeated but without the addition of PVA. The. dissolution up to a total of 100 g by means of the addition of extra water.

Composition of Example 2:

Polycondensate 6.6% by weight, Acronal 290D 0.67% by weight.

Example 3 (Comparative)

Example was repeated

Acrona 1.

Composition of the Polycondensed Example 6.6% in

Example 4 (Comparative)

Example 1 was repeated but without the addition of PVA or

3:

weight or but without the addition of Acronal.

The solution was prepared to a total of 100 g by means of the addition of extra water.

Composition of Example 4:

Polycondensate 6.6% by weight, PVA 0.9% by weight.

o ProGscix ^ x @ nx&gt; 0 cte essay χ®η.αχι &amp; χ &amp; π &amp; ο de aati ·

-----— ~ ---........................................ .......................... ~ Λα ~~~~~~~~~~~~ ^ ~~~~~ ™ ~~~ ~~~~ ™ ~ ™ ~~~ ™

The antifouling agents were coated on a stainless steel plate representative of the internal surface of a reactor. A uniform coating 10 was obtained with good adhesion to the surfaces shown by the absence of a material running down in ρ 1 aa »

The plates coated with the antifouling agent were subsequently placed inside the reactor against the reactor wall.

Subsequently, the polymerization of vinyl chloride in an aqueous suspension in the reactor was carried out. After completion of the polymerization, the reactor was purged and the polymer suspension was removed.

Next, the metal plates were removed from the reactor and any PVC polymer deposit formation was inspected and placed back in the reactor (once the reactor had been washed with water). The% coverage with anti-fouling agent and the% of

<td>training coverage</td><td>No deposit</td><td>from</td><td>Pvc</td><td>through</td><td>from</td>

<td>visual evaluation</td><td></td><td></td><td></td><td></td><td></td>

<td>Then,</td><td>started</td><td>a</td><td> 2^to</td><td>reaction</td><td>from</td>

<td>polymerization. Further,</td><td>they took</td><td>cape</td><td>a</td><td>total has</td><td>ta</td>

polymerizations and the following measurement was carried out.

Results

Table 1 Retention of antifouling agent after 5 repeated polymerizations

<td rowspan="2">Ex pio</td><td colspan="5">% coverage of anti-fouling agent</td>

<td>Polymerization ation 1</td><td>Polymerizer ation 2</td><td>Polymerization ation 3</td><td>Polymerization ation 4</td><td>Polymerizer ation 5</td>

<td> 1</td><td> 100</td><td> 60</td><td> 50</td><td>4Q</td><td> 40</td>

<td> 2</td><td> 100</td><td> 90</td><td> 90</td><td></td><td> 90</td>

<td> 3</td><td> 91)</td><td> 40</td><td> 20</td><td> 10</td><td> 5</td>

<td> .4</td><td> 80</td><td> 50</td><td> 40</td><td> 30</td><td> 30</td>

Table 2 PVC tank on the plates after 5 p o1ime ri za ci one s repe ti das

<td></td><td></td><td>% of Cobert</td><td colspan="2">zura, PVC tank</td><td></td>

<td>E j emp</td><td>Polymerize</td><td>Polymerize</td><td>Polymerize</td><td>Polymerize |</td><td>Polymerize</td>

<td>the</td><td>tion 1</td><td>tion 2</td><td>tion 3</td><td>tion 4 |</td><td>tion 5</td>

<td>JL</td><td> 0</td><td> 5</td><td> 5</td><td colspan="2"> 20 | 50</td>

<td>or</td><td> 0</td><td> 0</td><td> 0</td><td> 0 ___1</td><td> 0</td>

<td> 3</td><td> 5</td><td> 10</td><td> 20</td><td> 50</td><td> 55</td>

<td> 4</td><td> 0</td><td> 5</td><td> 10</td><td> 4 5</td><td> 50</td>

It is evident from these results that the composition of the invention is extraordinarily better than the prior art compositions in which the poly (acr.il.ato ester) is absent. In addition, the results demonstrate that the polyacrylate binder works best in the absence of PVA. The difference is commercially desirable since it increases the availability of the reactors, not only for the time it takes to add the antifouling composition to the reactor, but also the time the reactor is allowed to stand to allow drainage of the anti-fouling composition in excess. This can be of the order of a 2-5% reduction in the reactor cycle time for each batch, for example 7-10 minutes of savings for every 360 minutes of the reactor cycle time.

This can also lead to a total increase in productivity. For example, productivity in terms of downtime due to breakdowns when the reactor is not out of operation for antifouling re-coating, anti-fouling drainage and reactor cleaning can be greater than 90% for a series for example of 2, 3, 4, 5, 6, 7, 8, 9, 10 or more consecutive polymerization batches.

In addition, it is verified that PVC obtained using the composition of the invention is whiter in terms of method

7 of yellow index 3 * than the PVC obtained by means of polymerization of VCM in reactors treated with the antifouling compositions of the prior art. The PVC whiteness measured by the yellow B * index method for PVC wet cake is usually reduced by 50% and can also improve the color of the wastewater.

In addition, the inventors have found that the presence of polyacrylate (co) polymer increases stability against the presence of oxygen (ie, a reduced rate of color change to a dark blue solution observed with a condensation of 1- naphthol and formaldehyde). This, in turn, provides an additional contribution to the advantage of a greater whiteness of the dry white PVC polymer and makes the process less sensitive during bottling or packaging of the anti-fouling composition.

Other acrylate polymers have also been tested using the above methods. It has been found that Acronal A378, a copolymer with acrylonitrile and butyl acrylate, also improves retention of the antifouling agent on the reactor wall and reduces PVC deposits.

8

NEW OF ΙΑ INVENTION

Having described the invention as above, it is considered as a novelty and, therefore, is claimed as property contained in the following: