DE2601148A1 - METHOD OF RECOVERING PROTEINS AND POLYMERS FROM LIQUIDS CONTAINING THE SAME - Google Patents

Description

PATENT LAWYERS

K.SIEBERT G. GRÄTTINGER

Dlpl.-Infl. Dipl.-Ing., Dipl.-Wi'rtsch.-Ing.

813 Starnberg near Munich P.O. Box 1649, Almeidaweg 12 Telephone (08151) 1 27 30 and 41 15 Telegr.-Adr .: STARPAT Siarnberg

~ 1

the

Lawyer file: 6614/2

International Basic Economy Corporation 1271 Avenue of the Americas, New York, New York 10020, USA

Process for the recovery of proteins and polymers from liquids containing the same.

The invention relates to an improvement of the German patent application P 25 05 000.4 (method for coagulation of protein).

- 2 -

609883/1086

Postal checking account Munich 2726-804 ■ Kreissparkasse Starnberg 68940 ■ Deutsche Bank Starnberg 59.17570

ORIGINAL INSPECTED

The subject matter of the application mentioned relates to a method for coagulation which is to be improved in this way von'Protein in which a coagulable protein is treated with a coagulant for protein is, the invention of the application mentioned is characterized in that a liquid mixture of the coagulable protein and the protein coagulant are subjected to turbulent flow conditions to allow highly effective coagulation of protein to take place. Examples of coagulable Proteins that can be treated by the method according to the invention are animal blood, soybeans, Cottonseed and coconut extracts, sweet and sour whey from cheese factories, and vegetable juices such as those from alfalfa, algae and water hyacinth plantations.

It has surprisingly been found that the basic method according to the earlier application under the following conditions also for the recovery of polymers from a dispersion or solution of the Polymer can be used by coagulants or desolventizers.

The following detailed consideration is intended to provide a better understanding of the invention disclosed herein.

It is known that many commercially important polymers and copolymers are produced by emulsion polymerization of the original monomer or monomers. The polymers made by this process include polychlorobutadiene (neoprene), styrene butadiene rubber, Polybutadiene, polyethylene, polypropylene,

609883/1 086

- 3 -

2601H8

Butadiene-acrylonitrile copolymer and many others known to the person skilled in the art and given in the literature Polymers. In one method of polymerizing an emulsion, the monomer is first in one aqueous agent emulsified with a suitable reaction catalyst. The emulsifier used creates a stable emulsion of the monomer or monomers in the aqueous phase. Various im Additives dissolved in monomers cause, direct and finally terminate the polymerization process as in known procedures. The end product of the process of polymerizing the emulsion is a stable one Colloidal dispersion of a well-ordered polymer or copolymer in water, called "latex".

With normal storage and handling, there is essentially no coalescence or agglomeration of the polymer particles in a stable latex. A microscopic image of fine typical latex shows many small polymer particles with an average diameter of about 0.1 to 5 or more micrometers. Many latices have particle sizes of about 0.1-0.5 micrometers. The particle size of ¹ various commercial neoprene latexes varies for example between about 0.11 and 0.15 microns. Each individual polymer particle is surrounded by an essentially monomolecular layer of emulsified molecules.

Latex particles have an affinity for water; H. they are hydrophilic and tend to attract water and to keep a firm covering of water around you. The colloidal latex particles also have electrical properties Traits that affect their behavior.

609883/1 086

-A-

2601U

For example, electrical charges on the particle surface create an electrostatic field on, in which largely corresponding to the concentration differences between cations and anions on the Particle surface potential differences exist. The electrical potential at the interface, i.e. H. at the plane representing the proportion of liquid moving with the particle around the particle from the proportion that can move independently of the particle is called the zeta potential.

The stability of the latex depends largely on the equilibrium acting on the colloidal latex particles the different attraction and repulsion forces. The attractive forces are usually Van der Waalsche Called forces. The repulsive forces have their origin in the zeta potential and in the bound liquid, the envelops the colloidal particles.

In many cases it becomes desirable or necessary to agglomerate or concentrate the polymers of the latex To separate and regain form. The prior art knows many physical and chemical processes for concentrating or breaking polymeric latices, such as. B. centrifugation, evaporation, freezing and addition of acids, electrolytes and other latex coagulating agents. The main purpose of most this method consists in reducing the repulsive forces between the latex particles to the extent that the forces of attraction prevail. When this is the case, the latex particles grow together to form larger particles which are commonly called "lump of polymer", "lump of rubber" or "lump" that very much can be more easily separated from the system. The severed ones

60S883 / 1 086

2BÜ1H8

Particles then become a drainage device in the usual manner transported, such as B. screw presses or dewatering screens for final recovery dried or dehydrated polymers.

In general, it is desirable to coagulate latex to a particular particle size that makes it easier to coagulate can be transported in the conveyor system and handled in the dewatering device. When the coagulated Particles are too small, they cannot be conveyed properly. They can also pass through the openings in the drainage sieves flow and / or drain with the waste water from the screw presses. On the other hand, are the coagulated Particles too big can result in various types of conveying and handling problems, for example blockages and insufficient dehydration of the particles. The presence of uncoagulated material is also a serious one Problem with large particles. If a variety of very different particle sizes are also added, will uniform dewatering and particle drying are difficult. These problems can be overcome or minimized when the latex particles are coagulated to a controlled particle size.

Various methods are known for the coagulation of latices. For example, many latices can be added by adding one or more electrolytes are coagulated to a controlled particle size. For example, this is off U.S. Patent Nos. 2,366,460, 2,385,688, 2,386,449, 2,393,208,

2 393 348, 2 408 128, 2 459 748, 2 469 827, 2 476 822,

3 053 824 and 3 498 935 can be seen. It is believed that the Electrolyte by reducing the layer thickness of the bound water on the latex particle and / or by reduction

60 9 883/1086 - ⁶ -

2601H8

of the zeta potential causes the particles to grow together.

Coagulation usually takes place in a batch or continuous coagulator in which Latex and coagulant can be mixed. The recovered polymer lump is then washed to remove the electrolyte residue to remove. The washing process is important as it has a high degree of electrolytic or other waste materials in the lump can cause detrimental processing of the polymer or an unacceptable one Product results.

In many cases, however, the addition of electrolyte to the latex creates large clumps or agglomerates of polymer, which do not have a sufficiently large surface area or porosity to effectively wash out the Effect electrolytes. These lumps can also contain uncoagulated latex and are often difficult to use conveyed or drained. The problem of clumping is, for example, with polychlorobutadiene (neoprene) -Latices especially predominant, made up of relatively small hydrophilic particles with a strong negative Charge. The polychlorobutadiene latex particles are in a violent Brownian motion, the causes a chain reaction during coagulation with the result that undesirably large agglomerates of coagulated polychlorobutadiene. Polychlorobutadiene coagulation is very sensitive and difficult to control.

About the difficulties of uncontrolled coagulation Several methods have been proposed to minimize latex particles into large, relatively non-porous clumps.

609883/10 8 6

2601U8

For example, in the publication Chemical Engineering Progress ("Trans.Section") , in the article "Continuous Isolation of GR-M From Latex", Volume 43, No. 8, pages 391 to 398 (August 1947) a method is described in which a polychlorobutadiene emulsion is dissolved into a layer by freezing the latex. During the subsequent washing process, the frozen water in the layer melts and leaves a porous structure which allows the layer to be effectively washed. A disadvantage of this process is the low level of production compared to conventional coagulation processes. GB-PS 876 indicates the difficulties of coagulating polychlorobutadiene and natural rubber using electrolytes and proposes to solve the problem of using an aqueous solution containing several different types of electrolytes as a coagulant.

Many commercially important polymers and copolymers are also opposed by polymerizing a solution to the above-mentioned method of polymerizing an emulsion. Those made by polymerizing a solution Polymers and copolymers include polyisoprene, polybutadiene, natural balate rubber, styrene-butadiene Rubber and others known to the person skilled in the art and described in the literature. When polymerizing in The solution is the monomer or monomers and the additions that initiate, direct and limit the polymerization, dissolved in a liquid, which liquid is usually an organic liquid in which the polymeric product is soluble. The polymerization takes place in the liquid to create a solution that is about 1 to Contains 50% dissolved polymer. As with the emulsions and latices, it is often necessary to use the polymer or copolymer recover and isolate from the solution.

609 883/108 6

2601U8

Various methods of recovering and isolating the dissolved polymer from such solutions have been disclosed, See, for example, U.S. Patents 2,530,144, 2,561,256, 2,607,763, 2,833,750, 2,844,569, 2,957,855, and 2,957,861 conventional processes, the polymer solution is treated with a desolvent isiermittel, such as steam or hot water, which is essentially immiscible with the solvent and in which the polymer is essentially insoluble is. The desolventizer heats the polymer solution to a point where the solvent evaporates. When the desolventization takes place, the polymer is obtained from the solution in the form of solid particles that are in longer particles agglomerate. The end result is a slurry with polymeric particles and the liquid desolventizer, from which the polymer is recovered.

The desolventization usually takes place in a continuous or staged process in which the polymer Solution and. the desolventant can be mixed at atmospheric pressure or under vacuum. For economic For reasons, the evaporated solvent is usually condensed, recovered and used as a recycled solvent fed back into the polymerization process.

The difficulties addressed above with regard to the recovery and isolation of polymers from latices also apply to the recovery and separation of polymers from solution by desolventization. The formation of excessively large lumps or aggregations of polymers, for example, as indicated above, pose a serious problem. So the purpose is such a desolventization of the polymer solution that one a polymer with a controlled particle size is obtained to facilitate handling, washing and drying of the

609883/108 6

2601H8

Polymer to facilitate. In addition, there is the recovery of polymers from solution or from latex generally disturbed by heat and mass transfer, as in our earlier application in connection with the coagulation of blood has been discussed. The coagulants and desolventants must be used first the polymer particles or solvent reach before effective coagulation or desolventization can take place. Heat transfer is a particular problem in the desolventization of poly- mer solutions where the thermal energy supplied by the desolventizing agent is transferred to the solvent once the desolventant reaches the solvent to prevent evaporation of the solvent trigger. The large amounts of energy required for desolventization are a major disadvantage of these processes. A recovery process for polymers with low residence times and low energy consumption is ~ extremely desirable.

In order to solve the above problems, in accordance with the invention, there is provided a method of recovery of polymers from a dispersion or solution of the polymer by treating the dispersion or solution with in each case created a coagulant or desolventizer, which is characterized in that within of a volume of liquid, a local turbulent zone is formed and a dispersion or solution of the polymer as well as the coagulation or desolventizing agent is introduced into the local turbulent zone, and that upon introduction, an anionic surface treatment agent is further introduced into the turbulent zone of a dispersion, wherein the surface treatment agent regardless of whether any surface treatment agent is in the dispersion is present, is supplied.

60 9 883/1086

- ίο -

The turbulent zone is preferably created at the end of a high shear stir flight.

When the dispersion is a polymer latex, an aqueous electrolyte solution is preferably used as the coagulant used. On the other hand, when treating a solution of polymers, it is used as a desolventant Used steam.

The polymer and the coagulant or desolventant are introduced separately into the system at a point which ensures that a substantial part of it gets into the turbulent zone and before leaving the system flows through this zone. The polymer and the coagulating or desolventizing agent mix in the highly turbulent zone under conditions of a highly effective heat and mass transfer, making a highly effective almost instantly Generation of polymer particles in the zone takes place as a result of coagulation or desolventization. That Polymer is created as a flowable sludge from finely divided particles whose size is changed by changing the speed the impeller can be controlled.

By directing the polymer and the coagulant or desolventant The mixing, heat and mass transfer and coagulation take place in the locally highly turbulent zone or desolventization in a highly beneficial environment instead of. The polymer particles formed in the zone are small and separate. These particles are in the carrier liquid spreads and forms an easily flowable sludge that facilitates the continuity of the process. The procedure can by continuously feeding the polymer and the coagulating or desolventizing agent into the highly turbulent zone and continuously removing a sludge

609883/1086

- ii -

2601H8

be carried out continuously with polymer particles.

Where a polymeric latex has been coagulated it becomes necessary to add the anionic surfactant to the turbulent zone to enter the agglomeration of coagulated polymer particles into larger and larger Minimize particles. The presence of an anionic surfactant during coagulation implies control over the degree of coagulation and agglomeration of the polymeric particles rather than that Result the remaining particles stay small and separate and within the desired range the particle size. It is believed that the anionic surface treating agent by reduction the interfacial tension of the particles stabilizes particle growth.

It has been found that due to the highly effective nature of the process, the polymer containing liquid can be diluted substantially without adversely affecting the coagulation process. An advantage of dilution the liquid is that the resulting sludge becomes even more flowable and therefore at a continuous one Throughput can be handled more easily. As essentially all "polymers and the coagulant or desolventant flow through the highly turbulent zone, a product is obtained which, following the drying or dewatering process, does not contain any moist lumps of uncoagulated material or partially coagulated material, which causes final product scrap or other undesirable results could. The complete and uniform drying, dewatering and washing of the recovered from the process Polymer product is made possible by the ability to control the particle size of the recovered material within

609883/1086

- 12 -

2601H8

the prescribed desired areas facilitated. Complete and even drying or drainage is also facilitated by the non-lumpy nature of the recovered particles. There further the Particles are not lumpy, nor will the particles adhere or stick to the inside walls of the dryer or other devices for the process and is therefore the drying capacity of the dryer and the Functionality of the other devices for the Procedure not worsened.

The inventive method can be used for continuous and effectively recovering a wide variety of dissolved or suspended in a variety of liquids Polymers used by coagulation or desolventization to create a flowable sludge, in which the recovered polymer is in the form of uniformly shaped, non-lumpy particles of high quality is present that is easily separated from the sludge and completely and evenly dried, drained, washed or can be treated in any other way. The small particle size of the recovered particles and those not The lumpy nature of the particles results in a flowable sludge which eliminates the difficulty of clogging solids-induced disruptions in flow overcomes the major problem with many known systems for continuous polymer recovery.

The size of the recovered polymer particles can be as desired without affecting the production volume of the final product to be affected by changing such parameters as the coagulant, the degree of dilution of the dispersion or solution to be treated, the amount of anionic surface treatment agent, the speed

609883/10 86

- 13 -

2601H8

of the stirring blade and the like · can be controlled.

The invention is explained below with reference to drawings. It shows

Fig. 1 is a schematic flow diagram of a

preferred embodiment for polymer coagulation,

Figure 2 is a schematic flow diagram of a preferred embodiment for the polymer desolvents is ation

Ordinary reference numerals may have been used in FIGS. 1 and 2.

First of all, it should be explained that the view of the lower part of the coagulation vessel according to FIGS. 1 and 2 is identical to FIG. of the earlier application, and that the cross section of the lower part is identical to that in Fig. 3 of the earlier application shown cross-section is identical. For this reason, neither the view of the lower part nor its cross-section shown in the accompanying drawing. The stirring blade used in the coagulation kettle of FIGS. 1 and is also identical to the stirring blade shown in Fig. 4 of the earlier application, which is why a detailed one Drawing of the impeller is not included in the accompanying drawing.

Referring to Figure 1, polymeric latex 60 is continuously fed into the coagulation vessel 16 approximately at the level of the high shear impellers 18 supplied by the latex feed pump 62. The coagulation vessel 16 (including overflow 23) and the high shear stirrer blade 18 corresponds essentially to the embodiment used for blood coagulation.

609883/1086

- 14 -

Latex 60 is a stable aqueous emulsion, suspension or dispersion of finely designed polymer particles that typically has a solids component of about 20 to 60 percent by weight. The particle size of the substantially uniformly distributed polymeric particles ranges, for example, from an average about 0.1 to 5 or more micrometers in diameter.

Latex 60 is preferably prepared by polymerizing an emulsion and usually includes small ones Amounts of one or more surface treatment agents known to be present to stabilize the latex are. The importance of the surface treatment agent in a polymeric and by polymerizing an emulsion latex produced is detailed in "Surface Active Agents and Detergents" Edition II, A. M. Schwarz, et al, "Interscience", pages 671-680 (1958). The amount of stabilizing surfactant present in latex is known to vary widely, for example from about 1 to 10 parts by weight per 100 parts of polymer solids and depends on factors such as the type of polymer added, the solids of the Latex and the particular polymerization reaction of the emulsion used. Nature and type of latex surfacing agent can generally be used with the more common stabilizing surface treatment agents for the same reasons, which are known to be normally found in polymeric latices vary widely. There were for example anionic, cationic and nonionic surfactants are used, although many of the more significant commercial ones Latices stabilized by anionic surface treatment agents will.

The chemical nature of the polymer is considered not to be that special

609883/1086 -15-

2601U8

viewed critically insofar as it relates to the present invention. Any of the common polymers Latices can be effectively coagulated by the method according to the invention. This includes latices from natural and synthetic polymers, such as. B. polychlorobutadiene, acrylonitrile-butadiene copolymers, Acrylonitrile-butadiene-styrene, copolymers, silicone rubber, polyethylene, polypropylene, polyurethane, polybutadiene, etc. The invention can be useful with latices made from thermoplastic, curable, elastomeric, or non-elastomeric polymers be used. A preferred latex is an emulsion-polymerized polychlorobutadiene latex which is approximately Contains 30 to 40 weight percent solids and an average polymer particle size between approximately 0.11 and 0.15 micrometers. The polychlorobutadiene latex can be any of those commonly available Types such as B. G, W or WRT types. It presents particular difficulties in the known methods Polychlorobutadiene latices to coagulate because of the difficulty in interrupting the once started Coagulation. In the method for coagulation according to the invention However, the polychlorobutadiene coagulates into separate, substantially uniformly shaped and shaped Particles of controlled size.

The latex coagulant 61 and excess anionic surfactant 62 (see Fig. 1) are added continuously introduced below the stirring blade 18 into the turbulent zone of the coagulation tank, namely preferably via a single inlet 63 by means of a feed pump 17. The coagulant 61 and the anionic However, surface treatment agents 62 can also enter the turbulent zone in two separate flows 40 are introduced within the coagulation container. It is important that the coagulant 61 and the supplied anionic surface treatment agents 62 in the turbulent

809883/1086

• - 16 -

2601H8

Zone 40 with the latex 60 are in intimate contact and mixing.

The coagulant 61 can be any material, the latex breaks up or destabilizes and the individual latex particles coagulate into larger particles 65 (see FIG. 1). The mechanism by which the various latex coagulants coagulate the latex is well known to those skilled in the art as well as the large number of coagulants available for coagulating the various latices are known and need not to be repeated here in detail. Suffice it to say that common latex coagulants are electrolytes and ionizable substances such as inorganic acids, bases and salts. For example Salts of alkali and alkaline earth metals (such as sodium, potassium, lithium, calcium, magnesium, barium), aluminum, Iron, silver, nickel, cobalt, titanium and similar latex coagulants. Halogen and sulfate salts of these metals are heavily used. Salts of polyvalent metallic cations are particularly preferred. The salts ionize in the latex and neutralize the batch of latex emulsifiers. This breaks or destabilizes the emulsion by allowing the individual latex particles to grow together. Depending on factors such as B. the degree of stability of the latex, strong or weak electrolytes can be used will. Other factors, such as the temperature of the latex, can also influence the choice of coagulant influence.

Although only a single coagulant is preferably used, one or more can be used with the latex Coagulant mixed v / ground. Magnesium sulfate, aluminum sulfate, barium chloride or other salts with less electrical conductivity are used as coagulants

609383/1088 - 17 -

2601H8

preferably used, especially in the case of a polychlorobutadiene latex, since polychlorobutadiene is very common is used as an electrical insulating means. As some residual coagulant, for example approximately 10 to 50 ppm normally remain in the polymer end product, have substances such as magnesium sulfate, aluminum sulfate and barium chloride have the advantage of being less conductive than some of the other common coagulants such as sodium chloride.

The amount of coagulant used can depend on a number of factors, the main factor being the temperature of the latexxist. For example, lower latex temperatures generally require lower amounts of coagulant and vice versa, since the surface tension is reduced at the lower temperatures is. Polymeric latices ground at temperatures around 0 C to 100 C, preferably in the range of the ambient temperature of approximately 15.5 ° C to 37.8 C.

The coagulant 61 is preferably in the form of an aqueous solution, usually about 1 to 10 percent by weight and preferably about 4 to 6 weight percent coagulant is introduced into the turbulent zone 40. The coagulant is shown in the coagulation container in an amount of approximately 9.08 g to 227 grams, and preferably about 22.7 grams to 113.5 grams, per 454 grams of solid latex particles on a dry basis. It must sufficient coagulant are supplied to at least initiate coagulation of the latex. Excess coagulant can be used, but usually for economic reasons and to better control coagulation is avoided. For example, have about 36.32 to 81.72 grams of aluminum sulfate or magnesium sulfate per 454 grams

60-9 883/1086 -18-

polymeric solid causes a satisfactory coagulation of polychlorobutadiene latices.

The anionic surface treating agent 62 is a thoughtful addition to the coagulation tank 16 beyond what is normally found in the polymer Latex 60 may be present. This excess anionic surface treatment agent is necessary incorrect agglomeration of the coagulated polymeric particles 65 into lumps, large spheres, or the like prevent clogging of equipment and making washing, drying and handling difficult. It has found that among the numerous surface treatment agents available only the anionic family of surface treatment agents is the one that is satisfactory Particle growth control is conditional.

The excess anionic surfactant is preferably used with the coagulant prior to introduction into the turbulent zone 40 of the coagulation vessel mixed (Fig. 1). The excess surface treating agent could flow as a separate stream into zone 40 or before the latex introduced into the coagulation tank will be fed to the latex 60 provided it is affected not contrary to the stability of the latex.

An anionic surface treating agent as used herein is any compound that is usually at least partially organic in nature and within the same molecule two Contains dissimilar structural groups - a water-soluble or hydrophilic group and a water-insoluble or hypo- phobic group, and whose water-soluble group is a polar group that is negative in aqueous solutions or dispersions is loaded.

609383/1086

- 19 -

2601U8

The particular type of anionic surface treatment used: means is generally of no critical importance. The four major subclasses of the anionic surface treatment family, all of which are useful in the present invention are those in which the polar group Is carboxylate, sulfonate, sulfate or phosphate ester.

The carboxylates have the general formula, (RCOO) ^- M ⁺ , in which R is usually a C "to C_. Alkyl group and M is a metallic or amine ion such as Na ⁺¹ , K ⁺¹ , Mg ⁺² , Ca ⁺² , Ba ⁺² , Fe ⁺² , Al ⁺³ , and preferably a monovalent ion. The carboxylates given include materials such as N-acyl sarcosinates and acylated protein hydrolysates.

The sulfonates generally have the formula RSO-Na, where R is normally a hydrocarbon group such as an alkyl or alkylarylene group in a molecular weight range in the surface treatment agent of, for example, C _g to C-. is. The sulfonates include alkyl benzene sulfonates, petroleum sulfonates, sulfosuccinates, and naphthalene sulfonates. The sodium salt of linear dodecylbenzenesulfonate is a common anionic sulfonatic surfactant.

The sulfates are probably the most widely used anionic surfactants and possess the general formula ROSO-M, where R is an alkyl or alkylarylene group in the molecular weight range of the surface treatment agent and M is an ion as defined above for the carboxylates. The sulfates shown include sulfated natural fats and oils, sulfated oleic acid, sulfated alkanols, amines, sulfated Esters, sulfated polyethylene oxide, alkylphenols and alkyl polyethylene oxide sulfates. Is sodium laurine sulfate a common member of the family and one to use

60S883 / 1086

- 20 -

2601H8

preferred anionic surface treatment agent in the invention.

The phosphate esters include such materials as alkyl orthophosphates, Alkyl polyphosphates and ethoxylated phosphate esters.

Additional anionic surface treatment agents used for Use as surface treatment agents 62 are suitable, can be found in detail in publications such as "Kirk-Othmer Encyclopedia of Chemical Technology ", 2nd Edition, Volume 19, pages 512 to 531, Intersience (1969);" Surface Active Agents ", AT THE. Schwarz, et al., Pages 25 to 148, Intersience (1949) and "Surface Active Agents and Detergents", Volume II, A. M. Schwarz, et al., pp. 25-102, Intersience (1958), publications incorporated herein by reference.

The amount of anionic surfactant can vary very widely and depends on factors such as the type of latex entered and the size and type of desired coagulated particles 65. If too little surface treatment agent is used, the coagulated particles may become excessively large. If too much surface treatment agent is used, the coagulated particles may not only be too small, but may be the surface treatment agent is the coagulated polymer contaminate improperly. As pointed out above, low levels of soiling in the final polymer are common to many Applications are unimportant and therefore normally no more additives than necessary for coagulation are used. Sufficient excess of anionic surfactant 62 and over and above that normally present in latex 60 is introduced into turbulent zone 40 at about 9.08 to 90.8 grams and preferably to provide approximately 18.16 to 45.4 grams per 454 grams of latex solids on a dry basis. The surface treatment agent is preferably used as an aqueous solution

6 0 P S B 3/1 0 8 6

- 21 -

26Ü1U8

about 1 to 5 % and preferably about 1 to 3% surface treatment agent is added.

In the preferred embodiment shown in FIG.
form are the coagulant 61 and excess
anionic surfactant 62 dissolved in water and
the resulting aqueous solution 63, which contains both additives, is then introduced into the turbulent zone 40 of the coagulation container. The solution 63 is the zone 40 under stable working conditions at a volume amount of
about 5 to 12, and preferably about 5 to 10 times that
Amount of entered latex 60 supplied. This secures
the generation of the vortex 24, the effective operation of the coagulation tank on a continuous
Base allowed. If the ratio falls below about 5, the slurry 66 could in some cases become overloaded with coagulated solids, possibly causing problems such as the destruction of the vortex, loss of the high turbulence in zone 40 and overloading of the agitator drive motor 19. If a ratio greater than 12 is used, the process could be performed satisfactorily, but would increase because of the increased amount of material to be processed
tend to be less effective. The various other and "procedural and
Apparatus parameters, such as stirring blade speed, blade end speed, blade diameter, space between stirring blade and walls of the coagulation container, point of introduction of the latex, the coagulant and anionic
Surface treatment agents, hold times, dimensioning and design of zone 40, etc. are essentially the same as described above in connection with blood coagulation.

The greater part of the latex 60 is coagulant 61 and

609883/1086

- 22 -

2601U8

the anionic surface treatment agent 62 is used in the local turbulent zone 40 is introduced at the tip of the stirring blade 18, where it is thoroughly diffusing under Mix mass transfer rates so that coagulation and agglomeration occur essentially immediately of the latex particles takes place and not further during subsequent processing or handling of the latex needs to be driven forward. The size of the coagulated polymer particles 65 in the withdrawn through the overflow 23 Slurry 66 can be controlled by varying the speed of sheet 18 as desired. The particles 65 are in are generally spherical in shape and have an average diameter of about 1.59 to 4.77 mm.

The resulting slurry 66, which has been drawn off from the coagulation container 16, is then used in an ordinary washing and washing machine Sifting process 68 subjected to wash contaminants from the particles 65 and the pulp or sludge and the Wash liquid 69 from the washed polymeric solids 70 to separate. These solids are then passed to a conventional drying device 71 for recovery of the polymeric end products 72 supplied.

The ability to control the particle size of the polymeric particles in the slurry 66 greatly facilitates handling and the transport of the pulp, reduces the contamination in the coagulation container and thus greatly facilitates the Washing process, separation, drying and other process steps after the coagulation tank. The parts of the polymer for example, do not contain undesirable cores of sealed uncoagulated latex and are more easily uniform wash and dry. As is known to those skilled in the art, these are significant advantages, particularly in the Case of the notoriously difficult to handle latices, such as

609883/1086

- 23 -

2601U8

for example polychlorobutadiene latices.

The recovery of the polymer from the solution is described below. As can be seen from Fig. 2, the polymer solution 80 is introduced into the turbulent zone 40 of the coagulation tank below the stirring blade 18. A Desolventant, preferably steam 21, is added in similarly given to zone 40, where an effective heat and mass transfer between the solution 80 and the Steam 21 takes place. This allows the solvent 82 to evaporate which is then vaporized to the kettle is withdrawn. The evaporated solvent withdrawn can be condensed and returned to the process as recycled if desired Solvent for the preparation of the polymer solution 80 are fed back.

The polymer dissolved in the solution 80 is preferably any polymer which is produced by a polymerization process Solution can be prepared, the solvent 82 of the solution being any material in which the monomer or the monomers and the resulting polymer and other components of the reaction mixture are soluble. Under the More common polymer solutions which are treated according to the invention are those of polyethylene, Ethylene-propylene copolymer, polyisoprene, polybutadiene, more natural Balate rubber, styrene butadiene rubber (SBR) and various types of sron C'opolymers. SBR is a preferred one Polymer solution.

The solution 80 can of course be prepared by means other than solution polymerization, for example, by Solution of the polymeric solids in a suitable solvent. However, it is believed that the main application of the invention in the processing of a reaction product

609883/1086 -24-

2601H8

a solution polymerization. Usually the solution 80 is made in accordance with conventional procedures treated to remove the polymerization catalyst and unreacted monomer prior to performing the desolventization process of the invention to remove. The solvents in solution 80 are usually organic liquids, which do not essentially mix with water and, for example, various alkyl hydrocarbons such as hexane, isoctane (isoctane), decane and others containing more than 6 or more carbon atoms as well as various Types of aromatic and other known solvents for polymers, for example, toluene, cyclohexane, and the various Xylenes.

The concentration of the polymer in the solution can vary widely and depends on how the solution was prepared, the type of polymer and the particular solvent used. Solution 80 contains about 1 to 50 %, and preferably about 2 to 20 %, of dissolved polymer.

Although steam is a preferred desolventant, any liquid or gas could be used that in the solution 80 sufficient thermal energy to evaporate the solvent contained in the solution 80 can introduce, provided that in its liquid form there is no solvent for the polymer or otherwise was compatible with the polymer. The preferred desolventant is a gas or vapor that is present in the coagulation tank will condense to form a liquid that is substantially immiscible with the solvent in solution 80 is.

As the desolventant and the polymer solution mix in the turbulent zone 40, there is one there

609883/1 086

- 25 -

2601H8

very good mass and heat transfer between the two streams, v / which allows the solvent to evaporate essentially immediately and the dissolved polymer out of solution in Forms separate particles 86, the size of which is controlled by the speed of rotation of the blade 18. This creates a slurry 88 of polymeric particles 86 which is then withdrawn from the coagulation container and in the same manner how the polymer slurry 66 in FIG. 1 is processed to give a washed and dried final polymer product 90 produce. The slurry 88 is washed and sieved 92 to wash contaminants from the polymeric particles 86 and to separate the slurry and washing liquid 93 from the washed solid polymer particles 94, which then can be added to dryer 95 to produce final polymeric product 90.

The various process and apparatus parameters discussed, such as the stirring blade speed, blade end speeds, Blade diameter, space between the stirring blade and the walls of the coagulation tank, places of input of the polymer solution and the desolventizing agent, holding times, temperatures, dimensions and design of the Zone 40 etc. are essentially as discussed above in connection with the coagulation of blood and polymeric latices.

The polymeric particles 86 are generally of the same configuration and range of particle sizes like the polymeric particles 65 used in latex coagulation (Fig. 1) and anticipate all of the above in connection with the latex coagulation of the present invention discussed advantages.

A principal advantage of desolventization according to the invention is that significantly less steam is required

609883/1086 -26-

2601H8

is to evaporate and remove the solvent 82, since the mass and heat transfer between the Steam 21 and the polymeric solution 80 is so effective. This results in a desolventizing process with reduced Power consumption.

It can be stated that the inventive The process involves continuous and essentially instantaneous coagulation or desolventization of a polymer the conditions of a highly effective mass and heat transfer due to the polymer and the coagulation or Desolventizing agent is carefully directed into a locally highly turbulent zone in which the polymer is in solid form Particle of controlled size grows to create a pumpable, To give a flowable slurry or slurry of finely divided polymer particles, which is then effectively washed, separated and uniform can be dried.

The following examples serve to further illustrate the invention.

Example 1:

In this example, a polychlorobutadiene latex was used in coagulated essentially in accordance with the method shown in FIG. The boiler in which the coagulation was a cylindrical 316 stainless steel tank with an inner diameter of approximately 266.7 mm and was approximately 381 mm in height.

A commercially available polychlorobutadiene latex of the WRT type having a solids content of about 35 % and an average particle size of

- 27 -

609883/1086

2601H8

approximately 0.11 to 0.15 micrometers was continuously injected into two openings in the tank wall that were 6.35 mm in diameter, offset approximately 180 from each other and located approximately 88.9 mm above the bottom of the tank. A solution containing approximately 5 % dissolved magnesium sulfate coagulant and approximately 2.5% dissolved sodium laurine sulfate as excess anionic surfactant was continuously injected into the bottom of the tank through a 3.17 mm diameter opening with the center of the opening approximately 25.4 mm was arranged above the center of the tank bottom. The high shear impeller was a standard 91.6 mm diameter blade (Cowels) formed as a high shear blade with a sawtooth pattern on its edge, mounted on a drive shaft approximately 80.9 mm above the tank bottom. The sheet occupied approximately 38 % of the diameter of the coagulation tank. This blade dimension insured that substantial amounts of the latex, coagulant, and excess anionic surfactant would not short circuit the process by avoiding passage through the high shear turbulence zone at the tip of the stirring blade. The impeller was set to a speed of over 5000 revolutions per minute (top speed of approximately 1598.2 m / min) and generated a vortex in the coagulation tank.

A semicircular opening with a radius of 76.2 mm was formed at the top of the vertical wall of the coagulator, to create an overflow of the coagulation tank during the working process. At this overflow opening This was followed by an inclined channel on which the overflowing pulp was led out of the coagulation container. Of the Slurry was collected at the exit of the chute, sieved and dried. The coagulated latex particles were one size from about 1.59 to 4.77 mm and were spherical in shape.

609883/1086

- 28 -

2601H8

At the beginning of the process, a few liters of the solution, which contained magnesium sulfate and sodium laurine sulfate, placed in the coagulation tank and set the agitator blade to the desired speed. An additional Solution of magnesium sulfate and sodium laurine sulfate was then continuously poured into the coagulation tank in a sufficient amount Amount pumped in to maintain a vortex of the solution in the coagulation tank. Once a A stable state of the vortex was reached, the polychlorobutadiene latex was continuously fed through two openings with one Entered a diameter of 88.9 mm above the bottom of the coagulation container. The latex was in the coagulation area brought, d. i.e., the high shear turbulence zone, at an amount of about 0.946 liters per minute. Once a If a certain liquid level has been built up in the coagulation container, a slurry of the coagulated begins Lumps of latex in the magnesium sulfate-sodium laurine sulfate solution to overflow onto the inclined channel in the coagulation tank. The operation was then carried out under steady state conditions continued. Coagulation was then carried out at essentially ambient temperatures.

Example 2;

In this example, a solution of styrene-butadiene rubber (SBR) in a volatile, essentially with Water-immiscible organic solvent is desolventized in accordance with the method shown in FIG. The kettle in which the desolventization was carried out was the same cylindrical stainless steel tank as in Example 1 which was modified to ventilate and remove the evaporated solvent. The high shear impeller was the same as discussed in the previous example (Cowels) with a diameter of 91.6 mm,

609883/1086

- 29 -

which was 88.9 mm above the tank bottom.

To trigger the procedure, the tank was filled with water and steam was continuously poured into the water, as in example 1, given until the water temperature was approximately 93.5 ° C to 96.0 ° C. At this point the high shear impeller became started and set to a speed of over 5000 revolutions per minute to create a vortex in the tank to produce, which causes the overflow of part of the content into the gutter.

The SBR solution was then continuously fed into the turbulent zone at the tip of the impeller through two openings (Diameter 6.35 mm) inserted into the tank wall, which were offset from each other by an amount of approximately 180 ° and were arranged approximately at the same level as the impeller. Once the desolventization started has, as evidenced by the emergence of suitably large (1.59 to 4.77 mm in diameter) and generally spherical Particles of SBR in the overflowing slurry will indicate the speed of the feed pump for the SBR solution gradually increased until the temperature of the tank contents stabilizes at approximately 93.5 ° C to 96 ° C Has. At this point the stable working condition is reached, in which the SBR particles are continuously withdrawn from the tank will.

- patent claims -

609 883/108 6

Claims (13)

2601H8 Patent claims: .1. Process for the recovery of polymers from a dispersion or solution of the polymer by Treatment of the dispersion or solution with a coagulant or desolventizer, characterized in that a local turbulent zone is formed within a volume of liquid and the dispersion or solution of the polymer and the coagulant or desolventizing agent in the local turbulent zone is introduced, and that when a dispersion is introduced, an anionic zone continues Surface treatment agent is added into the turbulent zone, the surface treatment agent being added regardless of whether some surface treating agent is normally present in the dispersion. 2. The method according to claim 1, characterized in that the local turbulent zone by an agitator blade is generated and the zone is at the tip of the impeller. 3. The method according to claim 1 or 2, characterized in that that the dispersion is polymer latex and that the coagulant is an aqueous electrolyte solution is used. 4. The method according to claim 1 or 2, characterized in that that the solution is a solution of a polymer and that steam is used as a desolventant. 60988371086 - 31 - 2601H8 5. The method according to any one of claims 1, 2 or 4, characterized in that a solution of polyisoprene, Polybutadiene, natural balate rubber or styrene-butadiene rubber in the turbulent zone is introduced. 6. The method according to claim 3, characterized in that the latex is a polychlorobutadiene latex. 7. The method according to claim 3 or 6, characterized in that the coagulant and the anionic surface treatment agent are mixed together prior to introduction into the turbulent zone. 8. The method according to any one of claims 3, 6 or 7, characterized in that the agitator blade with a blade tip speed of at least about 450 m / min. 9. The method according to any one of claims 3, 6 or 7, characterized characterized in that the agitator blade at a blade tip speed of approximately 450 to 2000 m / min is working. 10. The method according to claim 3 or 6, characterized in that the agitator blade at a blade tip speed from about 450 to 2000 m / mih and a first stream of latex and a second separate stream of electrolytic Coagulant for the latex and an anionic surface treatment agent in the turbulent Zone is introduced, causing the flows in the turbulent zone to mix and particles of coagulated Create polymer. - 32 609883/1086 2601H8 11. The method according to any one of claims 2, 4 or 5, characterized in that the solution is a Is a solution of a polymer, and that the impeller at a blade tip speed of at least works about 450 m / min. 12. The method according to any one of claims 2, 4 or 5, characterized in that the solution is a solution of a polymer, and that the impeller is at a tip speed of about 450 to 2000 m / min works. 13. The method according to claim 4 or 5, characterized in that that the impeller operates at a blade tip speed of about 450 to 2000 m / min and a first stream with the solution of the polymer and a second separate stream of steam is introduced into the turbulent zone, whereby the currents mix in the turbulent zone and create particles of the polymer. Starnberg, January 12, 1976/10/62 609883/1086 Blank page