DE2724163A1 - PROCESS FOR CONTINUOUS MANUFACTURING IN MASS FOR POLYBLENDS - Google Patents

Description

DR. BERG DIPL.-NO. SYAY'sr DIPL-ING. SCHWABE DR. DR. SANDMAIX

PATENT LAWYERS «- -.

8 MÜNCHEN 86, POSTBOX 8602 45 ^ "

Lawyer file 2 8 121 _A «

27th, MAY ii? 7 ⁷

MONSANTO COMPANY
ST.LOUIS / MISSOURI / USA

Process for continuous mass production for polyblends

The invention relates to an improved process for continuous polymerization in bulk from solutions, which contain aromatic monoalkenyl monomers with a diene rubber dissolved therein. In this procedure the solution becomes continuous and progressive in a single reaction zone in stages, by evaporation cooled, stirred linear flow polymerization to a polyblend polymerized, which consists of a matrix polymer phase with predetermined molecular weight and

D / b 08-12

MMN | 9KK272 Ϊ Munich M, MaucrkiivhrrsiraUe 45 banks: Bayerische Vereinsbank Manchen 453100

9 * 7043 telegrams: BERGSTAPFPATENT Munich Hypo-Bank Munich 3 (90002624

913310 TELEX: 0524560 BERG d Posischeck Munich 65343-SOi

predetermined among molecular weight distribution and dispersed Rubber phase in which grafted and entrapped polymer is present. This leads to a good one Rubber quality to strengthen the polyblend.

It is known that polyblends made of rubber with aromatic monoalkenyl polymers have significant advantages because they result in preparations with good impact resistance for many areas of application. For making such Various processes have been proposed and used for polyblends, including emulsion, suspension and bulk polymerization processes, as well as combinations thereof. Graft blends prepared in bulk from an aromatic monoalkenyl monomer and rubber, while having useful properties, this method is relative to the achievable maximum degree of conversion of monomers into the polymer is practically limited, since the viscosities are high are and as a result, a great deal of energy and equipment is required if the reactions via a very low degree of conversion can be continued after the phase inversion has taken place. It was because of that Processes developed in which the initial polymerization in bulk up to a conversion point beyond the Phase inversion is carried out in which the viscosities are still practically controllable; then the obtained Prepolymerization syrup suspended in water or another inert liquid and the polymerization

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of the monomers practically complete.

In U.S. Patent No. 2,862,906, Stein et al. a bulk / suspension polymerization process of styrene in which Diene rubbers are dissolved, the rubber being grafted, inverted and dispersed as rubber particles with stirring will. After the phase inversion, the viscous mixture is suspended in water and the polymerization ceases At the end, creating a polyblend in the form of pearls.

These bulk / suspension processes are used commercially, but have the economic disadvantages of batch processes, where long cycles at relatively low temperatures are necessary to control the heat of polymerization are. Continuous bulk polymerization processes have great economic advantages when they are at higher rates Temperatures and higher speeds and the necessary control of the high heat of polymerization carried out can be. In the case of polyblends, the dispersed rubber phase must be formed and its morphology must be stabilized i.e. it must be retained during the continuous polymerization of the rigid matrix polymer phase, so that the physical properties of the polyblend meet the strict specifications.

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Various processes have been developed for the continuous bulk polymerization of polyblends. In the US PS 3 2U3 481 describe Ruffing et al. a process in which diene rubbers are predominantly converted into aromatic monovinylidene monomers dissolved and polymerized in four reaction zones. Such methods require separate reaction vessels with different ones Reaction conditions for each polymerization stage, including expensive multiple reaction vessels and special equipment.

In U.S. Patent 3,658,946, Bronstert et al. a similar process in which the prepolymerization step is carried out to a solids content of at most 16%, whereby a rubber particle with a certain structure is obtained. After Bronstert ¹ s description are separate for the final polymerization, non-stirred, downflow reaction vessel necessary, each having a particular combination of reaction conditions provides, so that the final properties of the polyblend are ensured.

A process for the continuous bulk polymerization of polyblends is described in US Pat. No. 3,903,202 two reaction vessels are used as a simpler polymerization process for polyblends.

The method of the invention relates to an improved continuous one A method of bulk polymerization of a solution containing an aromatic monoalkenyl monomer in

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in which a diene rubber is dissolved, the improvement being that

a) the solution continuously into the first stage of an isobaric, stirred reaction zone divided into stages is initiated,

b) the conditions in the reaction zone are maintained so that the solution is polymerized in the form of a series of successive, practically linear, flow-through polymerization, each subsequent stage within the zone having a continuous flowing through liquid contact from stage to stage; there is a pressure gradient from the first stage down to a last stage, which creates a practically linear flow; all stages are operated under shear agitation common evaporative cooling in the vapor phase and under isobaric conditions, so that in each stage, a steady-state polymerization at a controlled temperature of 100 ⁰ C to 180 ⁰ C under a pressure of UOOO to 60,000 kg / m ² takes place and each stage operates with a predetermined higher conversion rate of 10% to 90%;

c) a matrix polymer phase is continuously produced which contains an aromatic polymonoalkenyl polymer with a predetermined average molecular weight of 35,000 to 100,000 MWg _t , wherein a diene rubber phase in the form of particles with an average

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Chen diameter of 0.5 μm to 10 ] xm is dispersed and a polymer mixture is formed from polymer, rubber particles and monomer,

d) the polymer mixture is continuously withdrawn from the last stage,

e) the polymer mixture is continuously heated at 180 ⁰ C to 250 ⁰ C, until the rubber particles have up to a predetermined swelling index crosslinked and

f) the monomer is continuously separated from the polymer mixture resulting in a polyblend comprising the aromatic polymonoalkenyl and the diene rubber particles contains.

The monomer used in the invention contains at least one monoalkenyl aromatic monomer of the formula

C = CH ₂
Ar

wherein Ar is selected from the group consisting of phenyl, halophenyl, alkylphenyl, alkylhalophenyl, and mixtures thereof and X is selected from the group consisting of hate substance and an alkyl radical having fewer than 3 carbon atoms consists.

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Examples of the monomers used in the invention Methods that can be used are styrene; monoaromatic o-alkyl monovinylidene compounds, e.g. o-methylstyrene, α-ethyl styrene, α-methyl vinyl toluene, etc .; ring-substituted Alkyl styrenes such as vinyl toluene, o-ethyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, etc .; ring-substituted Halostyrenes, e.g. o-chlorostyrene, p-chlorostyrene, o-bromostyrene, 2,4-dichlorostyrene, etc .; Ring alkyl or ring halogen-substituted styrenes, e.g. 2-chloro-U-methylstyrene, 2,6-dichloro-4-methylstyrene, etc. If desired, mixtures of these aromatic monovinylidene monomers can also be used be used.

The process can also be used for the polymerization of monomer solutions of a diene rubber in which mixed monomers be used together with the aromatic monoalkenyl monomers, especially the alkenyl nitrile monomers, such as acrylonitrile and methacrylonitrile and mixtures thereof. Such monomer solutions should be 60 to 99 wt.% Of the aromatic monoalkenyl monomers, 1 to 39% by weight of an alkenyl nitrile monomer and 1 to 20% by weight of the diene rubber, from which monoalkenyl aromatic copolymer polyblends be formed with the composition of this solution.

In addition to the monomers to be polymerized, the preparation can, if necessary, contain catalysts or other

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components worth seeing such as stabilizers, molecular weight regulators, etc., included.

The polymerization can be initiated by thermal, monomeric free radicals in the process according to the invention however, any free radical generating catalyst can be used including actinic irradiation. Conventional monomer-soluble peroxy and Perazocatalysts can be used. Examples of catalysts are: Di-tert-butyl peroxide, benzoyl peroxide, Lauroy1 peroxide, Oleyl peroxide, toluyl peroxide, di-tert-butyl-diperphthalate, tert-butyl peracetate, tert-butyl perbenzoate, dicumyl peroxide, tert-butyl peroxide isopropyl carbonate, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexene-3 or hexyn-3, tert-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, cyclopentane hydroperoxide, Pinane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, etc., as well as their mixtures.

In general, an amount of catalyst of 0.001 to 3.0% by weight, preferably 0.005 to 1.0% by weight of the polymerizable Material added; this depends essentially on the polymerization temperatures.

As is known, it is often desirable to use molecular weight regulators such as mercaptans, halides and terpenes in relatively small proportions by weight, e.g. 0.001 to 1.0% by weight of the

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polymerizable material to be added. Processing the Monomerzuberei- 2% to 20% diluents such as ethylbenzene, ethyltoluene, Äthylxylol, diethylbenzene or benzene may be added to the viscosities at high conversions to control and exercise some molecular weight regulation. It can also be desirable to add relatively small amounts of antioxidants or stabilizers, such as the customary alkylated phenols. These can optionally be added during or after the polymerization . The preparation can also contain other additives, such as plasticizers, lubricants, dyes and non-reactive preformed polymer materials which are suitable for this or which are dispersible therein.

Are used diene rubbers that are soluble in the monomers described. The preferred diene rubbers are not more than -20 ⁰ C a glass transition temperature not exceeding 0 ⁰ C, preferably, (as determined by ASTM Test D-7H6-52 T) and be under one or more of conjugated 1,3-dienes selected, for example butadiene, isoprene, 2-chloro-l, 3-butadiene, 1-chloro-l, 3-butadiene, Pipery len, etc. These rubbers include copolymers and block copolymers of conjugated 1,3-dienes and, up to an equal weight fraction, one or more copolymerizable, mono-ethylenically unsaturated monomers, such as the aromatic monovinylidene hydrocarbons (e.g. styrene; an aralkylstyrene, such as the o-, m- and

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p-methylstyrenes, 2,4-dimethylstyrene, the arylated ethylstyrenes, p-tert-butylstyrene, etc .; an o-methylstyrene, α-ethylstyrene, α-methyl-p-methylstyrene, etc .; Vinyl naphthalene, etc.); aromatic aryl halo monovinylidene hydrocarbons (e.g. the ο-, m- and p-chlorostyrenes, 2, U-dibromostyrene, 2-methyl-4-chlorostyrene, etc.); Acrylonitrile; Methacrylonitrile; Alkyl acrylates (e.g. methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc.), the corresponding Alkyl methacrylates; Acrylamides (e.g. acrylamide, methacrylamide, N-butyl acrylamide, etc.); unsaturated ketones (e.g. vinyl methyl ketone, Methyl isopropenyl ketone, etc.); o-olefins (e.g. Ethylene, propylene, etc.); Pyridines; Vinyl esters (e.g. vinyl acetate, vinyl stearate, etc.); Vinyl and vinylidene halides (e.g. the vinyl and vinylidene chlorides and bromides, etc.); and similar.

Although the rubber has up to about 2% of a crosslinking agent may contain, based on the weight of the rubber-forming monomer (s), can cause problems in crosslinking Solution of the rubber in the monomers for the graft polymerization reaction raise. It can also cause excessive networking lead to a loss of rubber properties.

A particularly preferred group of types of rubber are the stereospecific polybutadiene rubbers, which are produced by polymerization formed by 1,3-butadiene. This chew

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Schuke have an ice isomer content of about 30% to 9 8% and a trans isomer content of 70% to 2% and generally contain at least 85% polybutadiene, which was formed by l, U addition, and not more than 15% Polybutadiene formed by 1,2 addition. The Mooney viscosity of the rubber (ML-U, 100 ⁰ C) may be between 20 and 70, wherein a glass transition temperature of -50 ⁰ C to -105 ⁰ C, according to ASTM Test D-746-52 T.

A monomer solution which contains at least one aromatic monoalkenyl monomer and 1 to 20% by weight of a diene rubber dissolved therein is passed as a monomer rubber solution continuously into the first stages of an isobaric, stirred reaction zone which is divided into stages. A suitable stepped reaction vessel is described in U.S. Patent 3,903,202. The monomer is polymerized in the first stage at temperatures of 110 ^° C. to 115 ^° C., 10 to 50% by weight of the monomer being converted to an aromatic alkenyl polymer with a molecular weight of 10,000 to 100,000 MW «. At least part of the polymerized polymer is grafted onto the diene rubber in the form of polymer molecules as a super strate.

The amount of the polymeric superstrate grafted onto the rubber substrate can be between 10 parts by weight per 100 parts substrate and 250 parts by weight and even more per part substrate vary, the preferred graft mix

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however, polymers generally have one superstrate: Substrate ratio from 20 to 200: 100, preferably from 30 to 150: 100. With graft ratios of 30 to 150: 100 there is generally an extremely desirable improvement in various properties.

The remainder of the polymer formed is dissolved in the monomer solution and forms a monomer-polymer solution. The monomer-polymer solution or phase is incompatible with the monomer rubber solution or phase and due to the known Phase separation is observed due to the Dobry effect. The polymer concentration of the monomer-polymer phase increases and is its volume is slightly larger than that of the monomer-rubber phase, then the monomer-rubber phase disperses in the form of rubber monomer particles. This is supported by the shear movement in the stirred first reaction zone.

The agitation must be vigorous and of sufficient shear to force the rubber particles uniformly through the monomer-polymer phase to disperse and determine their size. The intensity of stirring changes with the size and shape of the Reaction vessel, however, simple experimentation with a given stirred reaction vessel will reveal how strong must be stirred so that the rubber particles are homogeneously dispersed in the monomer-polymer phase. The rubber

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particle size can be varied between an average particle size of 0.5 μm to 10 μm, preferably from 0.5 μm to 5 μm, so that a compromise can be found between impact resistance and high gloss of the rubber-reinforced polyblend. Higher agitation speeds and shear movements can reduce the size of the dispersed rubber particles to decrease; they have to be controlled to such an extent that the particles get the predetermined size and are homogeneous be dispersed.

The continuously fed, 1 to 20% by weight of diene rubber containing monomer preparation dispersed in the first Step in steady state polymerization with stirring almost instantaneously and forms the rubber monomer particles which, after the polymerization is complete, form individual rubber particles. The conversion of monomers to polymers in the first stage is maintained at 10% to 50%. Of the The percentage by weight must be kept in such a way that the polymer content is greater than the rubber content of the monomer preparation, to ensure that the monomer-rubber phase is dispersed into a rubber-monomer particle phase having a predetermined particle size and is uniformly distributed throughout the monomer-polymer phase.

In the first stages, the rubber particle is grafted with a polymer, which promotes dispersion and stabilizes the morphology of the particle. During the dispersion the rubber-monomer-particles will be some monomer-polymer-

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Phase enclosed in the particle. The total of those included Monomer-polymer phase and the grafted polymer, which is contained in the particles, can be 1 to 5 g per Grams of diene rubber.

The dispersed rubber phase increases the strength of the polymeric polyblend; The Izod impact strength is measured here according to ASTM test D-256-56. It has been found that in the range of 1 to 20% by weight of rubber that is dispersed in the polyblend, the impact resistance corresponding to the proportion of rubber by weight increases. The impact strength is also determined by the size of the dispersed rubber particles, the larger particles in the range from 0.5 to 10 μm causing a higher impact strength. It was here mean particle size with a photosedimentometer according to that of Graves, M.J. et al. published procedures "Size Analysis of Subsieve Powders Using a Centrifugal Photosedimentometer", British Chemical Engineering 9: 742-744 (1964) measured. A Model 3000 Particle Size Analyzer from the Martin Sweets Company, 3131 West Market Street, Lousville, Kentucky used.

The mean particle size of the rubber particles also affects the gloss, with the smaller particles affecting the finished product The polyblend molded or film product gives a higher gloss, but the larger particles give a lower gloss. In the

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Selection of the optimal rubber particle size must meet the requirements for impact resistance and high gloss against each other be weighed. The range from 0.5 ym to 10 ym can be used for optimum impact resistance and high gloss will; 0.5 to 5 pm is preferred, is best 0.8 to 3 pm.

In the process, in the first stage 1.) the rubber particles must be formed and dispersed and 2.) the rubber particles are grafted and stabilized so that their size and morphology or structure are retained. the The amount of the above-described enclosed monomer-polymer phase is adjusted to a certain range, by steady state polymerization in which the monomer is converted into the polymer; at least one Part of it is grafted onto the rubber and stabilizes the rubber particle. It was found that the The higher the level of stabilization in the rubber particle, the more effective the rubber phase is for strengthening the polyblend Inclusion amount is. The rubber particle acts largely like a pure rubber particle when the inclusions during their stabilization in the initial stages and throughout the polymerization process to that described above Amount to be set. The rubber particle is also externally grafted, which affects its structure the size and its dispersibility in the monomer-polymer phase is stabilized.

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The first stage forms a polymer mixture from a monomer-polymer phase in which the rubber phase described is dispersed. The mixture is made by progressive, multi-stage, practically linear flow polymerization polymerized, with the conversion to the polymer from 10% to 50% in the first stage up to 50% to 90% in the the last stage of a staged, isobaric, stirred reaction zone proceeds. This leads to a gradual progressive increase of polymer in the monomer r-Riy me r phase. This turned out to be important for preservation the morphology or structure of the dispersed rubber monomer particles.

Unexpectedly it was found that in the first stage if the rubber particle is formed, the rubber monomer particle has a monomer content that is equal to the monomer content corresponds to the monomer-polymer phase. The rubber monomer particle stabilizes at this level as the monomer in the rubber particle polymerizes and becomes Graft polymer forms on the outside. The lower the degree of conversion or the amount of polymer in the monomer-polymer phase of the first stage, the higher the amount of monomer found in those rubber monomer particles formed when the rubber cement is introduced and dispersed in the monomer-polymer phase. However, if the conversion is high in the initial stage, the dispersion in the rubber phase particles is less

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Including monomer. As already described, the mixture is polymerized in the linear flow zone divided into stages, and the weight fraction of the polymer formed becomes progressively higher, with each stage having a slightly higher polymer content. The gradual linear Progressive polymerization not only resulted in a controlled polymerization of the monomer to usable polymers, but also unexpectedly preserved the integrity of the rubber particles. Without our fully understanding the process, becomes apparent when the rubber particle is grafted and settled in the entrapped monomer of the rubber particle the monomer-polymer phase does not easily form the monomer through the monomer-polymer phase from the rubber particle deducted as soon as the polymer content in the monomer-polymer phase during the polymerization in the step-like reaction vessel gradually increasing. It is assumed that because of the slow polymerization in the multistage linear reaction zone the polymer both in the rubber particle and in the monomer-polymer phase with about the same Velocity is formed, the total polymer content of the entrapped monomer-polymer phase of the rubber particle is therefore approximately the same size as the polymer content of the monomer-polymer phase, and the monomer is therefore not withdrawn will. As a result, the inclusion weight fraction is stabilized and remains in the first reaction vessel after formation practically constant.

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" % \ ~ 272AT63

It is possible to analyze the amount of the total entrapped polymer phase and the grafted polymers. The finished polymerized polyblend product (1 g) is in a 50:50 consisting of acetone and methyl ethyl ketone solvent (10 ml) dissolved, which the matrix of the polymer Phase dissolves and leaves the rubber phase dispersed. The rubber phase is used as a centrifuge Gel separated from the dispersion, dried in a vacuum oven at 50 ° C. for 12 hours and weighed as a dry gel.

% Dry gel weight of the dry _{gel 1f) n} in polyblend "weight of the polyblend% graft and % dry gel -% rubber _inn

Inclusions im = ^{x 10} °

rubber

Parts by weight

of graft polymer % dry gel -% rubber

and inclusion polymer =

per unit weight
of rubber

% Rubber determined by infrared spectrographic Analysis of the drying gel

According to the invention, about 0.5 to 5 g are included and grafted polymers per gram of diene rubber are preferred.

The swelling index of the grafted rubber particles is determined by leaving the above-described dry gel for 12 hours dispersed in toluene. The gel is centrifuged and

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the excess toluene poured off. The wet gel is weighed, ^{dried in a vacuum oven at 50 °} C. for 12 hours and weighed.

η 11 * λ weight of the wet gel yuexiinaex - _{weight of the} dry gel

As mentioned above, the amount of inclusion and graft polymer present in the rubber particle is in a proportion from 0.5 to 5 parts per part of diene rubber is present. So the percentage of dry gel measured above is the percentage Gel in the polymerize polyblend and represents the dispersed rubber phase with polymeric inclusions and polymeric The percentage of gel varies with the percentage of rubber in the monomer formulation and the total amount of grafted and entrapped polymer in the caustic phase.

The swelling index of the rubber described above is important for the final properties of the polyblend. A lower one Swelling index indicates that the rubber has been crosslinked by the monomer, during this in step e) in the rubber-monomer particle polymerized to a polymer phase. In general, this is followed by conversion of the monomer to the polymer including the rate of conversion of the monomer to the polymer in the monomer-polymer phase as they are is carried out in stages b) and e). In stage e) the temperature of the second mixture is up to 185 ° C

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250 ° C. and the monomer vapors are separated off in stage f) so that a finished polyblend is obtained. The rubber particles are crosslinked by heating the mixture to 185 ^° C. to 250 ^° C.; this heating must continue until the particles have reached a swelling index of 7 to 20, preferably 8 to 16.

The polymer of the matrix phase of the polyblend according to the invention preferably has a dispersion index M / M, where M is the Molecular weight is given as the average weight, while M is the average number of measures of the molecular weight (middle the molecular weight range); the index is between 2 and 4, preferably 2.5 to 3.5. The dispersion index is known to those skilled in the art and represents the molecular weight distribution, with small values corresponding to narrow molecular weight distributions and larger values corresponding to broader molecular weight distributions. The average molecular weights of the polymer of the matrix phase are preferably between 35,000 and 100,000 Staudinger, most preferably between 35,000 and 70,000.

The polymerization is flow-through in a generally horizontal, cylindrical, step-like, isobaric, agitated manner Reaction zone carried out in which the conditions are set so that the first mixture in progressive, multi-stage, practically linear flow-through polymerization is polymerized; in all stages of this reaction zone

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A shear agitation takes place and the cooling takes place by joint evaporative cooling in the vapor phase under isobars Conditions «so that a steady state polymerization in each stage takes place at a controlled temperature. Through the interfacial fluid contact between the stages creates a hydraulic pressure gradient from the first stage down to the last stage, which is practical causes linear flow through the reaction zone. All Stages operate at a predetermined degree of conversion and produce a polymer with a predetermined molecular weight distribution and an average molecular weight such that the structural integrity of the dispersed Rubber particle is retained. The polymer mixture produced in the reaction zone has a total polymer content that by the multistage steady state polymerization and the evaporation of the monomers is determined.

The reaction vessel operates under controlled isobaric conditions. For the temperature range normally of interest for aromatic alkenyl monomers, for example styrene polymerization, the operating pressure is from + 000 to 20,000 kg / m ² . The styrene reaction is exothermic and cooling occurs primarily through evaporation of some of the monomers from the reaction mass. Further cooling can take place via a jacket. Cooling by recycling condensed monomers into the reaction zone is also provided. The mass is boiling and the temperature is determined by the natural relationship between

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Determined vapor pressure and boiling point. This relationship is also dependent on the relative amounts of Riymer, Monomer and other substances (e.g. dissolved rubber, solvents and additives). As during the material flow through the reactor the amount of polymer increases continuously and the amount of monomer decreases accordingly through polymerization, the monomer content is further reduced by evaporation losses, the temperature increases progressively from the input to the output stage to.

In order to have space for the natural swelling of the boiling mass and the developing steam, the reaction vessel becomes usually operated only with a filling of 10% to 90%, preferably U0% to 80% of its volume.

The steam escapes from the reaction vessel into an external condenser, where it is condensed and can also be supercooled. This condensate can then be fed into the input stage of the The reaction vessel is returned, where a fraction of the previously evolved vapors is condensed again heated and mixed with other inflowing free substances.

In a multi-stage reaction vessel, each stage is thoroughly mixed and the reaction mass is practically homogeneous in itself. The separating disks between the stages prevent backflow of material between the individual compartments. Of the

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However, free space between the disk and the jacket allows a certain amount of backflow, but also enables the necessary flow Movement of the material through the steps from the inlet to the outlet of the reaction vessel in a virtually linear manner Flow.

In a subdivided stage reaction vessel, the first stage gives a relatively low degree of conversion because it is a monomer solution is continuously introduced into them. The rate of conversion is due to the high monomer concentration at this stage, however, it is relatively high.

In each subsequent stage, the degree of conversion is higher than in the previous one, which is the rate of conversion drops. However, this effect is offset by the fact that the temperature is higher and monomer from the Mass is evaporated. The total conversion to polymer that one obtained per unit filling of the multistage reaction vessel is: thus higher than in the case of a reaction vessel with one single stage that produces the same final degree of conversion at the same temperature.

The distance between the rotating step cutting disks and the cylinder wall can be 1% to 10% of the jacket radius, the higher values being appropriate for the reactor end where the conversion is high and the viscosity is maximum. the

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The polymer mixture is moved from stage to stage through this opening, as is the steam from the polymer mixture flows here in the opposite direction over the mass surface.

The monomer-polymer solution flows linearly, with a minimum of back-mixing, under a liquid pressure gradient from the first to the last stage of the reaction zone. The temperature in the reaction zone is controlled by pressure. The pressure is controlled so that the polymer solution is boiling due to the heat of polymerization and a Monomerdampfphase is withdrawn at a speed sufficient to the polymer solution at 100 ⁰ C to 180 ⁰ C and under isobaric conditions 4000-20000 kg / m ⁴ " to keep.

The monomer, e.g. styrene, polymerizes releasing around 69 8 kJ per kilogram of polymer. The heat of vaporization of the Styrene is about 349 kJ per kilogram evaporated, that The reaction vessel therefore releases about 2 kg of monomer from the polymer syrup per kilogram of polystyrene converted This amount of monomer is returned to the first polymerization stage in order to achieve steady state polymerization under controlled temperature and isobaric conditions.

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During operation, the reaction zone can be filled with polymerization solution from 15% to 90% of its volume, the remaining space is taken up by evaporated monomers. A mixture is withdrawn from the last stage of the reaction zone, in which the degree of conversion can be 50% to 90%. The last stage of the reaction zone is generally kept at higher temperatures (130 ^° C.-180 ^° C.) than the first stage. The polymers obtained therein have average molecular weights in the lower range of 30,000 to 70,000 Staudinger. The combined polymers can have molecular weights of 30,000 to 100,000 Staudinger, preferably 35,000 to 70,000 Staudinger. This flexibility makes it possible to produce a wide range of polymers with varying molecular weight distributions and with varying filling of the reaction zone.

For the operation of the reaction zone, it is preferred to use a continuous, isobaric, stirred reaction vessel which is divided into stages and which is evaporated by a vent Monomers is controlled above the liquid level present therein in order to control the temperature in the second reaction zone. The withdrawn stream of vaporized monomers is condensed in a condenser and collected in a container. It can be returned to the first stage of the reaction zone.

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To regulate the reaction zone, the temperature in the last stage of the reaction vessel preferred. The control system measures the temperature in the liquid phase of the final stage of the reaction vessel and uses a signal generated from it to set a temperature controller, which in turn is influenced by a signal from a setpoint generator in which a selected temperature is set. The signal obtained in this way that obtained by measuring the pressure in the vapor phase of the reaction vessel Signal is modified, is used to control a pressure regulator, which in turn is a pressure valve in the ventilation line controlled from the container with recycled condensed monomer. By adjusting the pressure above the condensed monomer in the container is the temperature set very precisely and quickly to a preselected desired value in the final stage of the reaction vessel. In each stage, the temperature quickly reaches an equilibrium value, determined by the container pressure and the polymer Solids content of the polymer solution in each stage.

The method according to the invention comprises a complete manufacturing process for aromatic polyalkenyl polyblends with high impact resistance. The mixture of polymer that is dispersed The liquid phase flowing out of the reaction vessel contains rubber and monomer, called the polymer mixture. This mixture has a polymer solids content of 50 to

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90% by weight. It is carried out with a suitable device, e.g. a gear pump, withdrawn and fed into one or more heating and degassing zones. A degassing zone can be operated at pressures below atmospheric pressure or at a certain vacuum.

In the process according to the invention, however, two or more degassing zones can also be used, if desired will. In the process described, the vaporized aromatic alkenyl monomers as well as their lower oligomers removed from the first degassing zone, condensed and fed into a container. From this the condensed monomers and oligomers can enter the first stage of the reaction vessel be returned. Likewise, those in a second degassing zone, which are generally less Pressure is operated as the first, evaporated monomers and oligomers drawn off, condensed and placed in a container. directs. From here, too, the condensed monomers and oligomers can be fed back into the reaction vessel. In the Oligomers evaporated from the two degassing zones are preferred distilled off from the evaporated monomers and separately returned to the reaction zone, or from the process taken.

In general, in making certain desired polymers, it has been found advantageous to use the polymers produced certain organic conditions with high boiling point

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3 »

to add. The addition is best done during the polymerization. These additives include internal lubricants such as petroleum or other heavy oils, or mold release agents such as fatty acids, fatty acid esters or salts and waxes. These additives can easily be introduced into the reaction zone, preferably in the last stage with the help of multiple dosing pumps.

If the method is carried out as described above, the correct regulation of iteaction vessels of the variable Type of filling bring extremely useful advantages. It is possible to use polymers with specific material properties and to prepare molecular weight distributions with the filling from values as low as 30% down to the high value of 100% of the nominal filling quantity can be varied in the individual production facility. This flexibility Capacity utilization is extremely useful as it allows rapid adjustment to market demand for the Total polymer quantity or the market shares of various polymers produced at the manufacturing facility can, makes possible.

The following examples are intended to explain the invention in more detail; unless otherwise specified, all shares are Parts by weight and all molecular weights are Staudinger values.

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example 1

A monomer preparation of 5,6 Gew.Anteilen sterospezifischem polybutadiene rubber in styrene monomer 94.4 Gew.Anteilen is made by 8 hours stirring the mixture at 40 ⁰ C (Diene 55 rubber is from the Firestone Rubber Co., Acron, Ohio) . 0.1 part of octadecyl 3- (3 ', 5'-di-tert-butyl-4-hydroxyphenyl propionate and 24 parts of recycled styrene monomer are added to this monomer preparation. 38 kg / hour of this mixture are continuously passed into a reaction vessel which has a capacity of about 189 l and works with about 45% filling.

The reaction vessel is 135 cm long. The agitator consists of a horizontal shaft to which a number of two-inch wide blades are alternately attached at right angles to one another. Two circular cutting disks attached to it rotate with the shaft; their radial distance from the mantle is on average 0.95 cm, they rotate at 10 rpm. The disks are arranged so that they divide the reaction vessel into three stages with approximately the same volume. A stream of a weight fraction of white petroleum is introduced into the end compartment of the reaction vessel. The pressure in the reaction vessel is kept at 0.91 kg / cm, the temperature of the first stage is 125 ^° C., that of the final stage 153 ^° C. The reaction syrup emerging from the reaction vessel contains 70% solids. The evaporated in the reaction vessel

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Styrene vapor is condensed and returned to the first stage. The syrup in the final stage is pumped out of the reaction vessel continuously so quickly that one substantially constant reactor filling is maintained; the syrup then becomes the inlet of a jacketed heating pipe pumped. This stage is achieved with the help of a throttle valve on the outlet side of the heater at a pressure of

H, 55 kg / cm held. The syrup emerging from this preheater stage has a temperature of 170 ^° C. After passing the throttle valve, the syrup flows into a two-stage degassing device as described in US Pat. No. 3,928,300, which has proven to be a useful system. The first degassing stage is operated at 220 ^° C. and about 60 torr. After flowing through the degasser intermediate valve, which regulates an approximately constant filling in the first degassing zone, the syrup flows into the degassing chamber of the second stage, which is kept at 15 Torr. US Pat. No. 3,928,300 describes a suitable degassing process.

The vapors leaving the degassing chambers are condensed and returned to the first compartment of the reaction vessel. 0.9 kg of these condensed vapors are withdrawn per hour. The degassed syrup is made from the second Degassing chamber pumped through a mold with the one

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Multiple strands are formed, which are then cut into pellets. The polymer obtained has a molecular weight of 59,000 Staudinger and a dispersion index of 2.2.

Typical properties Izod impact resistance Bars 1.27 χ 1.27 cm (kg / cm ² ) 5.45 Tensile strength (yield point)

(kg / cm ² ) 275

Tensile strength (break)

(kg / cm ² ) 294

Elongation at Break (%) 39 Source index 9

Proportion of grafting and inclusions Proportion / proportion of rubber 1.60

Rubber particle size (ym) 3.8 Example 2 Use of an initiator

The procedure was followed using the apparatus and procedure of Example 1 with the following exceptions:

a) The stirrer in the reaction vessel was turned about UO rpm operated. _ 30 _

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b) The monomer preparation fed also contained 0.006 Parts dicumyl peroxide.

c) The reactor filling was about 40%.

d) The reaction vessel was at a pressure of 0.8 kg / cm

held.

e) The syrup in the reactor compartment of the final stage had about 146 ⁰ C.

f) The syrup emerging from the reaction vessel contained about 65% solids.

Typical properties

Izod impact strength kg / cm ² 6.0

Tensile strength (yield point) kg / cm 301

Tensile strength (break) kg / cm ² 322

Elongation at Break 35

Source index 8

Grafts and inclusions

Parts / parts rubber 1.80

Rubber particle size (ym) 3.3

Molecular weight Staudinger 58,000

Dispersion Index 2.4

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272A1G3

Example 3

Monomer preparation with a lower rubber content The procedure was carried out as in Example 1 with the following exceptions:

a) The stirrer in the reaction vessel was operated at 40 rpm.

b) The monomer preparation fed in contained 3.3 parts of rubber and 96.7 parts of styrene.

c) The reactor filling was about 50%.

d) The syrup emerging from the first preheater stage was 195 ^° C.

Typical properties Izod impact strength kg / cm ² 4.36 Tensile strength (yield point) kg / cm 365 Tensile strength (break) kg / cm ² 359 Elongation at break 20 Source index 9 Proportion of grafting and inclusions / Share of rubber 1.40 Rubber particle size (μη) 3.1 Molecular weight Staudinger 55,000 Dispersion Index 3.1

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example

High rubber content «more compartments in the reaction vessel

The monomer formulation fed is similar to Example 1, but contains 8 parts rubber, 92 parts styrene and 29 parts recycled styrene monomer. The mixture is with 59.1 kg / h. fed into a reaction vessel as in Example 1, but it has 8 circular dividing disks, which divide it into 9 stages with approximately the same volume. The stirrer of the reaction vessel works at 15 rpm, the filling is 59%. The pressure in the reaction vessel is at 1.16 kg / cm held Syruptemperatur the last compartment at 157 ⁰ C. The exiting from the reaction vessel Syrup contains from 6 8% solids; it is degassed, extruded through a die into a plurality of strands that are cooled and pelletized. The vapors from the degasser are condensed and returned to the first stage of the reaction vessel. 1.36 kg / hour this condensate was drained.

Typical properties

Izod impact strength (kg / cm ² ) 12.0

Tensile strength (yield point) kg / cm 345

Tensile strength (break) kg / cm ² 302

Elongation at break 24

Swelling index 13.6

Proportion of grafting and inclusions /

Share of rubber 0.67

Rubber particle size (ym) 1.5

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Example 5

Example 1 was repeated, a solution of 7.2 parts of rubber dissolved in 92.8 parts of a monomer preparation containing 75% by weight of styrene and 25% by weight of acrylonitrile contained, used. The solution was treated as in Example 1, the separated polyblend had the following properties properties:

Izod impact strength Tensile strength (yield point) Tensile strength (break) elongation at break, swelling index

Proportion of grafting and inclusions / proportion of rubber

Rubber particle size

16, U kg / cm 457 kg / cm 359 kg / cm 25th % 12th 1.5 1.2 μΐη

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Claims (18)

Patent claims: Continuous process for polymerisation in Hasse a solution of an aromatic eny! »ono, in of a diene rubber is dissolved »characterized in that one a) the solution continuously in the first stage of an in Feeds in stages divided, isobaric, stirred individual reaction vessels, b) the conditions in this individual reaction vessel are maintained in such a way that the solution is polymerized in the form of a practically linear flow polymerization that follows one another in several stages, each subsequent stage being a continuous, flowing through has liquid contact from stage to stage and a pressure gradient from the first stage downwards to a final stage prevails, which produces a practically linear flow, furthermore all stages with shear stirring and common evaporative cooling in the vapor phase under isobars Conditions are operated so that in each stage a steady state polymerization at a controlled Temperature from 100 C to 180 C under a pressure of «» 000 to 60,000 kg / m ² takes place and each stage works with a predetermined higher degree of conversion of 10% to 90%; c) continuously produces a polymer mixture containing a matrix polymer, rubber particles and monomer, where- 709849/1127 - 37 - 27241G3 at the polymer an aromatic polymonoalkenylpolyeer with contains an average molecular weight of 35,000 to 100,000 HWg, wherein a diene rubber phase in Fon is dispersed by particles having an average diameter of 0.5 to 10 µm; d) the polymer mixture is withdrawn from the final stage of the individual reaction vessel; e) the polymer mixture is heated to temperatures of 180 ° C. to 250 ^° C. until the rubber particles are crosslinked; and f) the monomer and the polyblend from the polymer mixture separates. 2. The method according to claim 1, characterized in that the aromatic monoalkenyl compound Is styrene, o-methylstyrene, chlorostyrene, dichlorostyrene, bromostyrene, dibromostyrene or a mixture thereof. 3. The method according to claim 1, characterized in that the diene rubber is polybutadiene, polyisoprene, poly-2-chlorobutadiene, poly-1-chlorobutadiene, copolymers and block copolymers of butadiene styrene, butadiene chloroprene, chloroprene styrene, chloroprene isoprene, 2-chlorobuta diene-1-chlorobutadiene or a mixture thereof. - 38 - 709849/1127 4. The method according to claim 1, characterized in that the diene rubber is polybutadiene having a cis-isomer content of 30% to 98% and a Tg range of -50 ⁰ C to -105 ⁰ C. 5. The method according to claim 1, characterized in that the aromatic monoalkenyl monomer is styrene. 6. The method according to claim 1, characterized * that the common evaporative cooling in the vapor phase by simultaneous removal of a vapor phase containing the monomer from the stages of the reaction vessel, at speeds at which the solution in each stage at one temperature from 100 ^° C. to 180 ^° C. and under a pressure of 5,000 to 60,000 kg / m ² . 7. The method according to claim 6, characterized in that the removed vapor phase liquefies and is returned to the reaction vessel at a rate at which steady state polymerization is maintained. 8. The method according to claim 7, characterized in that the liquefied vapor phase in the 709849/1121 - ³⁹ - first stage of the reaction vessel is returned. 9. The method according to claim 1, characterized in that the solution in process step a) with is fed in at a rate which is equal to the rate at which the polymer mixture in the process stage d) is deducted. 10. The method according to claim 1, characterized in that the reaction vessel has two to fifteen Has stages. 11. The method according to claim 1, characterized in that the reaction vessel is a single, practically horizontal, continuous, stepped, isobaric, stirred reaction vessel. 12. The method according to claim 1, characterized in that 0.001 to 3 wt.% One in the solution free radical generating catalyst are included. 13. The method according to claim 1, characterized in that the free radical generating catalyst Di-tert-butyl peroxide, tert-butyl peracetate, benzoyl peroxide, Lauroyl peroxide, tert-butyl perbenzoate, dicumyl peroxide, tert-butyl peroxide, isopropyl carbonate or a mixture 709849/1127 mix of it is. 14. The method according to claim I _1, characterized in that the solution contains the rubber in amounts of 1 to 20 wt.% Dissolved. 15. The method according to claim I _1, characterized in that each of the stages operates during the steady state polymerization of the solution with a practically constant gravimetric filling of 15% to 90% of its volume. 16. The method according to claim I _1, characterized in that the first stage is operated at temperatures of 100 ⁰ C to 145 ⁰ C and a degree of conversion of 10% to 50%, the final stage, however, at temperatures of 130 ⁰ C to 180 ⁰ C and a conversion of 50% to 90%. 17. The method according to claim I _1, characterized in that the solution contains 60 to 9 8% by weight of the aromatic monoalkenyl monomer, 1 to 39% by weight of an alkenyl nitrile monomer and 1 to 20% by weight of the diene rubber. 18. The method according to claim I _1, characterized in that the polyblend separated in process stage f) contains rubber particles in which polymer in 709849 / 112t " ^H1 " grafted and entrapped form is present in an amount of 0.5 to 5 parts per part of rubber. 709849/1127